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1.
Phys Rev Lett ; 123(20): 208002, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31809118

RESUMO

Active particles such as swimming bacteria or self-propelled colloids spontaneously self-organize into large-scale dynamic structures. The emergence of these collective states from the motility pattern of the individual particles, typically a random walk, is yet to be probed in a well-defined synthetic system. Here, we report the experimental realization of tunable colloidal motion that reproduces run-and-tumble and Lévy trajectories. We utilize the Quincke effect to achieve controlled sequences of repeated particle runs and random reorientations. We find that a population of these random walkers exhibit behaviors reminiscent of bacterial suspensions such as dynamic clusters and mesoscale turbulentlike flows.


Assuntos
Coloides/química , Modelos Teóricos , Análise por Conglomerados , Movimento (Física)
2.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 75(12): 1383-1393, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31866636

RESUMO

This study aimed to evaluate the influence of change in respiratory motion on matchline (ML) and reduction of the effect by increasing ML levels of field matching technique in passive scattering proton therapy for esophageal cancer. To evaluate the influence of respiratory motion in terms of stability, we measured relative dose around ML using a respiratory motion phantom. The relative error was -0.5% when the respiratory motion phantom worked stable, whereas there was obvious change that the relative error was -25.5% when the difference of amplitude between upper field and lower field was one side 3 mm on each cranially and caudally direction. In clinical case of the seven esophageal cancer patients simulated by the treatment planning system, assuming the difference of amplitude was 3 mm, the relative error of maximum (minimum) dose in clinical target volume around ML against the original treatment plan were 5.8±1.2% (-6.0±2.7%), 3.3±0.9% (-3.8±1.0%), and 2.4±0.5% (2.6±0.8%) on average (±SD) when ML levels were 2, 4, and 6, respectively. Increasing ML levels can reduce the influence of respiratory motion.


Assuntos
Neoplasias Esofágicas , Movimento (Física) , Terapia com Prótons , Neoplasias Esofágicas/radioterapia , Humanos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador
3.
Zhonghua Yi Xue Za Zhi ; 99(47): 3725-3731, 2019 Dec 17.
Artigo em Chinês | MEDLINE | ID: mdl-31874498

RESUMO

Objective: To investigate the clinical value of magnetic resonance (MR) intravoxel incoherent motion (IVIM) diffusion imaging and 3D pseudo continuous arterial spin labeling (3D-pcASL) perfusion imaging in the evaluation of acute cerebral infarction. Methods: MR images of 49 patients with unilateral acute cerebral infarction diagnosed and treated in Affiliated Yancheng Hospital of Southeast University Medical College from October 2015 to February 2019 were retrospectively analyzed. High signal infarction area (S(D)) on diffusion image slice with the biggest lesion level and abnormal perfusion area (S(CBF)) on the corresponding level were measured. The presence of ischemic penumbra (IP) was represented by S(CBF)> S(D), and patients were divided into group IP and group non-IP. Regions of interest were set on the infarction core, brain tissue near the edge of the lesion (BNL) and their corresponding contralateral regions. The values of apparent diffusion coefficient (ADC), true diffusion coefficient (D), perfusion related diffusion coefficient (D(*)), perfusion fraction (f) and cerebral blood flow (CBF) of each region of interest were recorded and relative values of infarction lesion to its contralateral region (rADC, rD, rD(*), rf, rCBF) were calculated. Differences of each parameter value between infarction core, BNL and their corresponding contralateral regions and of each relative parameter value between infarction core and BNL, and between the two groups were compared.The differential diagnostic efficacy of relative parameter value with differences between groups was analyzed by receiver operating characteristics (ROC) curve. The correlations of each relative parameter value of 3D-pcASL and IVIM sequences were analyzed. Results: The ADC, D, f and CBF values of infarction core were significantly lower than those of contralateral regions in both groups (all P<0.01). Among all parameters of BNL in both groups, only the CBF value of group IP was significantly lower than that of contralateral region ((27.58±3.53) vs (41.20±5.66) ml·100 g(-1)·min(-1), P<0.01). The rADC, rD, rf and rCBF of infarction core were significantly lower than those of BNL in both groups (all P<0.01). The rCBF of BNL in group IP was significantly lower than that in group non-IP (0.68±0.12 vs 0.97±0.15, P<0.01), and the area under the curve was 0.949, the optimal threshold was 0.823, and the youden index was 0.855 for identifying the two groups. Other relative parameters values of infarction core and BNL had no statistical difference between the two groups. There were positive correlations between rCBF and rADC, rD, rf (r=0.428,0.335,0.565) of infarction core, rADC and rD, rf (r=0.853,0.602) of infarction core, also rADC and rD (r=0.336) of BNL (all P<0.05). Conclusions: IVIM can effectively evaluate the difusion and perfusion information of acute cerebral infarction lesions. However, its perfusion related parameters are not as good as 3D-pcASL in IP evaluation, which should be flexibly selected according to the actual needs of patients' condition evaluation.


Assuntos
Isquemia Encefálica , Isquemia Encefálica/diagnóstico por imagem , Infarto Cerebral , Imagem de Difusão por Ressonância Magnética , Humanos , Movimento (Física) , Imagem de Perfusão , Estudos Retrospectivos , Marcadores de Spin
4.
Phys Rev Lett ; 123(13): 138003, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31697550

RESUMO

We study the orientation statistics of spheroidal, axisymmetric microswimmers, with shapes ranging from disks to rods, swimming in chaotic, moderately turbulent flows. Numerical simulations show that rodlike active particles preferentially align with the flow velocity. To explain the underlying mechanism, we solve a statistical model via the perturbation theory. We show that such an alignment is caused by correlations of fluid velocity and its gradients along particle paths combined with fore-aft symmetry breaking due to both swimming and particle nonsphericity. Remarkably, the discovered alignment is found to be a robust kinematical effect, independent of the underlying flow evolution. We discuss its possible relevance for aquatic ecology.


Assuntos
Modelos Teóricos , Fenômenos Fisiológicos Bacterianos , Fenômenos Biomecânicos , Hidrodinâmica , Modelos Biológicos , Movimento (Física) , Natação
5.
Nat Commun ; 10(1): 4744, 2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31628338

RESUMO

Coexistence of order and fluidity in soft matter often mimics that in biology, allowing for complex dynamics and applications-like displays. In active soft matter, emergent order can arise because of such dynamics. Powered by local energy conversion, this behavior resembles motions in living systems, like schooling of fish. Similar dynamics at cellular levels drive biological processes and generate macroscopic work. Inanimate particles capable of such emergent behavior could power nanomachines, but most active systems have biological origins. Here we show that thousands-to-millions of topological solitons, dubbed "skyrmions", while each converting macroscopically-supplied electric energy, exhibit collective motions along spontaneously-chosen directions uncorrelated with the direction of electric field. Within these "schools" of skyrmions, we uncover polar ordering, reconfigurable multi-skyrmion clustering and large-scale cohesion mediated by out-of-equilibrium elastic interactions. Remarkably, this behavior arises under conditions similar to those in liquid crystal displays and may enable dynamic materials with strong emergent electro-optic responses.


Assuntos
Coloides/química , Elasticidade , Eletricidade , Modelos Teóricos , Termodinâmica , Cristais Líquidos/química , Movimento (Física) , Tamanho da Partícula
6.
Medicine (Baltimore) ; 98(42): e17075, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31626080

RESUMO

Motion-induced artifacts have been a major drawback in bladder cancer imaging. This study is to evaluate the clinical utility of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) acquisition in improving motion-induced artifacts in T2-weighted (T2W) magnetic resonance imaging (MRI) of bladder cancer at 3T.Sixteen patient MRI exams were included. Using a Likert scale, 2 radiologists independently scored T2W data without and with PROPELLER in terms of artifact severity and tumor visualization. Statistical analysis was done to assess the image quality improvement by PROPELLER and inter-observer variability.Without PROPELLER, the median scores of artifact severity and tumor visualization were 1.5 and 1.5 for reviewer 1, and 2.0 and 2.0 for reviewer 2. With PROPELLER, the scores increased to 3 and 3.5 for reviewer 1, and 3.5 and 3.5 for reviewer 2. Despite the inter-observer variability (κ scores < 0.2), both reviewers found significant improvement in artifacts and visualization (all P < .001).PROPELLER acquisition significantly improved the image quality of T2W-MRI. These initial findings indicate that this technique should be utilized in clinical MRI of the bladder.


Assuntos
Artefatos , Carcinoma de Células de Transição/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Neoplasias da Bexiga Urinária/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador/métodos , Movimento (Física) , Variações Dependentes do Observador , Estudos Prospectivos , Melhoria de Qualidade , Neoplasias da Bexiga Urinária/patologia
7.
Top Magn Reson Imaging ; 28(5): 235-244, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31592990

RESUMO

Magnetic resonance imaging (MRI) is an appealing technology for fetal cardiovascular assessment. It can be used to visualize fetal cardiac and vascular anatomy, to quantify fetal blood flow, and to quantify fetal blood oxygen saturation and hematocrit. However, there are practical limitations to the use of conventional MRI for fetal cardiovascular assessment, including the small size and high heart rate of the human fetus, the lack of conventional cardiac gating methods to synchronize data acquisition, and the potential corruption of MRI data due to maternal respiration and unpredictable fetal movements. In this review, we discuss recent technical advances in accelerated imaging, image reconstruction, cardiac gating, and motion compensation that have enabled dynamic MRI of the fetal heart.


Assuntos
Coração Fetal/diagnóstico por imagem , Cardiopatias Congênitas/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Diagnóstico Pré-Natal/métodos , Feminino , Coração Fetal/embriologia , Humanos , Movimento (Física)
8.
Sensors (Basel) ; 19(18)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505727

RESUMO

With the development of wearable devices, strain sensors have attracted large interest for the detection of human motion, movement, and breathing. Various strain sensors consisting of stretchable conductive materials have been investigated based on resistance and capacitance differences according to the strain. However, this method requires multiple electrodes for multipoint detection. We propose a strain sensor capable of multipoint detection with a single electrode, based on the ultrasound pulse-echo method. It consists of several transmitters of carbon nanotubes (CNTs) and a single polyvinylidene fluoride receiver. The strain sensor was fabricated using CNTs embedded in stretchable polydimethylsiloxane. The received data are characterized by the different times of transmission from the CNTs of each point depending on the strain, i.e., the sensor can detect the positions of the CNTs. This study demonstrates the application of the multipoint strain sensor with a single electrode for measurements up to a strain of 30% (interval of 1%). We considered the optical and acoustic energy losses in the sensor design. In addition, to evaluate the utility of the sensor, finger bending with three-point CNTs and flexible phantom bending with six-point CNTs for the identification of an S-curve having mixed expansion and compression components were carried out.


Assuntos
Técnicas Biossensoriais , Entorses e Distensões/diagnóstico , Dispositivos Eletrônicos Vestíveis , Capacitância Elétrica , Humanos , Movimento (Física) , Movimento/fisiologia , Respiração , Entorses e Distensões/fisiopatologia
9.
J Phys Chem Lett ; 10(19): 5917-5922, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31509419

RESUMO

Nuclear magnetic relaxation provides invaluable quantitative site-specific information on the dynamics of complex systems. Determining dynamics on nanosecond time scales requires relaxation measurements at low magnetic fields incompatible with high-resolution NMR. Here, we use a two-field NMR spectrometer to measure carbon-13 transverse and longitudinal relaxation rates at a field as low as 0.33 T (proton Larmor frequency 14 MHz) in specifically labeled side chains of the protein ubiquitin. The use of radiofrequency pulses enhances the accuracy of measurements as compared to high-resolution relaxometry approaches, where the sample is moved in the stray field of the superconducting magnet. Importantly, we demonstrate that accurate measurements at a single low magnetic field provide enough information to characterize complex motions on low nanosecond time scales, which opens a new window for the determination of site-specific nanosecond motions in complex systems such as proteins.


Assuntos
Ressonância Magnética Nuclear Biomolecular/métodos , Proteínas/química , Isótopos de Carbono , Cinética , Campos Magnéticos , Movimento (Física) , Prótons , Ubiquitina/química
10.
Opt Express ; 27(17): 24082-24092, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31510302

RESUMO

This paper investigates the performance of the neural network (NN) assisted motion detection (MD) over an indoor optical camera communication (OCC) link. The proposed study is based on the performance evaluation of various NN training algorithms, which provide efficient and reliable MD functionality along with vision, illumination, data communications and sensing in indoor OCC. To evaluate the proposed scheme, we have carried out an experimental investigation of a static indoor downlink OCC link employing a mobile phone front camera as the receiver and an 8 × 8 red, green and blue light-emitting diodes array as the transmitter. In addition to data transmission, MD is achieved using a camera to observe user's finger movement in the form of centroids via the OCC link. The captured motion is applied to the NN and is evaluated for a number of MD schemes. The results show that, resilient backpropagation based NN offers the fastest convergence with a minimum error of 10-5 within the processing time window of 0.67 s and a success probability of 100 % for MD compared to other algorithms. We demonstrate that, the proposed system with motion offers a bit error rate which is below the forward error correction limit of 3.8 × 10-3, over a transmission distance of 1.17 m.


Assuntos
Redes de Comunicação de Computadores , Movimento (Física) , Fenômenos Ópticos , Fotografação , Algoritmos
11.
Eur J Radiol ; 120: 108672, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31550637

RESUMO

PURPOSE: To determine the diagnostic potential of Intravoxel Incoherent Motion (IVIM) MRI for differentiating malignant spinal tumours from acute vertebral compression fractures and tuberculous spondylitis, and to compare IVIM with diffusion-weighted imaging (DWI) and chemical shift imaging (CSI). METHODS: The Institutional Review Board approved this prospective study, and informed consent was obtained. IVIM MRI, DWI, and CSI at 1.5 T were performed in 25 patients with 12 acute compression fractures, 14 tuberculous spondylitis, and 18 malignant spinal tumours. The parameters of these techniques were assessed using the Kruskal-Wallis test. The diagnostic performance of the parameters was evaluated using receiver operating characteristic (ROC) analysis. RESULTS: ADC, SIR, Dslow, Dfast, and f values of malignant tumours were significantly different from those of acute compression fracture (for all, p < 0.05). The mean Dslow and Dfast values of malignant spinal tumours had significant differences compared with those of tuberculous spondylitis (for all, p < 0.05). However, no significant differences were observed in any quantitative parameters between the acute compression fracture and the tuberculous spondylitis (p > 0.05). Dslow•f showed the highest AUC value of 0.980 (95%CI: 0.942-1.000) in differentiating acute compression fracture and malignant spinal tumours. Dslow showed the highest AUC value of 0.877 (95%CI: 0.713-0.966) in differentiating tuberculous spondylitis and malignant spinal tumours. CONCLUSIONS: IVIM MR imaging may be helpful for differentiating malignant spinal tumours from acute vertebral compression fractures and tuberculous spondylitis.


Assuntos
Fraturas por Compressão/diagnóstico , Fraturas da Coluna Vertebral/diagnóstico , Neoplasias da Coluna Vertebral/diagnóstico , Espondilite Anquilosante/diagnóstico , Tuberculose da Coluna Vertebral/diagnóstico , Adulto , Idoso , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Projetos Piloto , Estudos Prospectivos , Curva ROC , Sensibilidade e Especificidade
12.
NeuroRehabilitation ; 45(2): 229-237, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31498140

RESUMO

BACKGROUND: Normative data for the equivalent of gait speed via the Wheelchair Propulsion Test (WPT) do not exist for wheelchair users. OBJECTIVE: The purposes of the current study were to: 1) determine the reliability of the WPT, 2) propose and compare normative values for the WPT for young adult males and females utilizing three different propulsion techniques, and 3) compare how different wheelchair types affect performance on the WPT. METHODS: 50 young adults (25 of each sex) performed the WPT using three different propulsion techniques in three different types of wheelchairs. Participants were asked to propel a wheelchair over 10 m at a comfortable speed. Time and number of pushes were recorded for three trials for each propulsion technique in each type of wheelchair. RESULTS: All of the ICC(2,2) values were >0.83 for speed and number of pushes. Normative values for speed, number of pushes, push frequency and effectiveness categorized by propulsion technique, sex and wheelchair type were developed. CONCLUSIONS: Preliminary normative values have been established for young adults performing the WPT. This study highlights the need to maintain consistency of the wheelchair type and propulsion technique between trials in order for the WPT to be reliable.


Assuntos
Cadeiras de Rodas/normas , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Movimento (Física) , Movimento , Padrões de Referência , Reprodutibilidade dos Testes , Cadeiras de Rodas/efeitos adversos , Cadeiras de Rodas/classificação , Adulto Jovem
13.
Hum Mov Sci ; 67: 102512, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31493622

RESUMO

Due to the redundant degrees of freedom (DOF) and nonlinearity of reactional kinetic elements within the human motor apparatus, controlling the complex dynamics of the human musculoskeletal system presents considerable difficulties. Based on this challenge, Bernstein (1967) viewed skill development as the process whereby the central nervous system (CNS) gains mastery of kinematic DOF and kinetic reactional elements (passive forces, moments etc.), with the highest level of skill characterised by optimal exploitation of reactional elements in the achievement of movement goals. A previous kinematic investigation into coordination differences in a complex multidirectional dance sequence demonstrated that general unfreezing of kinematic DOF occurred as dance skill progressed (Chang et al., submitted for publication). To gain insight into the role of angular reactional elements in skill, the present kinetic study investigated angular momentum and associated variables across three skill levels (beginners, intermediates, experts) within this same complex dance sequence. The results showed that the angular momenta of segments and accompanying angular reactional elements generally increased with skill level. More specifically, the findings suggested that while improvements in movement economy from cancellation of angular momentum between body segments occur early in skill progression, later in skill progression, experts utilise increased whole-body angular momentum. Although this is energetically expensive, it may enhance the aesthetic value of dance movements, and/or have mechanical advantages. Overall, the findings here provide support for Bernstein's (1967) model of skill development. Future research should quantify the relations between energy expenditure, key biomechanical variables that reflect skill and dance aesthetics as perceived by audiences.


Assuntos
Dança/fisiologia , Destreza Motora/fisiologia , Adolescente , Adulto , Fenômenos Biomecânicos/fisiologia , Feminino , Humanos , Cinética , Masculino , Movimento (Física) , Movimento/fisiologia , Adulto Jovem
14.
Transplant Proc ; 51(7): 2391-2396, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31474296

RESUMO

OBJECTIVE: To evaluate the diagnostic accuracy of Intravoxel Incoherent Motion (IVIM) parameters for assessment of tumor response after locoregional treatment (LRT) of hepatocellular carcinoma (HCC). METHODS: Fifteen patients with HCC who had undergone LRTs (11 transarterial radioembolization, 4 transarterial chemoembolization) were included. In addition to routine upper abdominal magnetic resonance imaging sequences, IVIM with 16 different b values and conventional diffusion weighted imaging with 3 different b factors were obtained immediately before and 8 weeks after LRTs. Magnetic resonance imaging response was evaluated according to modified Response Evaluation Criteria in Solid Tumors (mRECIST) and HCCs were categorized into 2 subgroups, responders and nonresponders. Quantitatively, the number of diffusion-changes were calculated with apparent diffusion coefficient (ADC) and IVIM parameters, including mean D (true diffusion coefficient), pseudo-diffusion coefficient associated with blood flow, and f (perfusion fraction) values. Subsequently, the pre- and post-treatment parameters were compared using the Mann-Whitney U test. RESULTS: Considering all HCCs, a significant decrease was observed according to mRECIST criteria (-38.43 ± 16.49). The ADC and D values after LRTs were significantly higher than those of the preceding ones. The f values after LRTs were significantly lower than those of pre-treatment. In the responders group, ADC and D values were significantly increased and f values were significantly decreased after LRTs. No difference of statistical significance was achieved in the nonresponders group. CONCLUSIONS: ADC values and IVIM parameters appear to reflect the response of LRTs as effectively as those of mRECIST. This promises new horizons in the management of pretransplant patients, especially in renal insufficiency clinical settings, owing to the elimination of contrast media administration.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Transplante de Fígado , Imagem por Ressonância Magnética/estatística & dados numéricos , Cuidados Pré-Operatórios/métodos , Adulto , Idoso , Braquiterapia/estatística & dados numéricos , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Quimioembolização Terapêutica/estatística & dados numéricos , Meios de Contraste , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Feminino , Humanos , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Período Pré-Operatório , Resultado do Tratamento
15.
Transplant Proc ; 51(6): 1861-1866, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31399170

RESUMO

BACKGROUND: To evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) parameters in estimation of hepatocellular carcinoma (HCC) grading. MATERIALS AND METHODS: Twenty-nine patients with histopathologically diagnosed as 42 HCC at explant were included in this retrospective study. All patients were examined by 1.5T magnetic resonance imaging with the use of 4-channel phased array body coil. In addition to routine pre- and postcontrast sequences, IVIM (16 different b factors varying from 0 to 1300 s/mm2) and conventional diffusion-weighted imaging (3 different b factors of 50, 400, 800 s/mm2) were obtained with single-shot echo planar spin echo sequence. Apparent diffusion coefficient (ADC) and IVIM parameters including mean D (true diffusion coefficient), D* (pseudo-diffusion coefficient associated with blood flow), and f (perfusion fraction) values were calculated. Histopathologically, HCC was classified as low (grade 1, 2) and high (grade 3, 4) grade in accordance with the Edmondson-Steiner score. Quantitatively, ADC, D, D*, and f values were compared between the low- and high-grade groups by Student t test. The relationship between the parameters and histologic grade was analyzed using the Spearman's correlation test. To evaluate the diagnostic performance of the parameters, receiver operating characteristic analysis was performed. RESULTS: High-grade HCCs had significantly lower ADC and D values than low grade groups (P = .005 and P = .026, retrospectively); ADC and D values were inversely correlated with tumor grade (r = -0.519, P = .011, r = -0.510, P = .026, respectively). High-grade HCCs had significantly higher f values when compared with the low-grade group (P = .005). The f values were positively correlated with tumor grade (r = 0.548, P = .007). The best discriminative parameter was f value. Cut-off value of 32% of f values showed sensitivity of 75.6% and a specificity of 73.5%. CONCLUSION: ADC values and IVIM parameters such as f values appear to reflect the grade of HCCs.


Assuntos
Carcinoma Hepatocelular/patologia , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Interpretação de Imagem Assistida por Computador/estatística & dados numéricos , Neoplasias Hepáticas/patologia , Gradação de Tumores/estatística & dados numéricos , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Gradação de Tumores/métodos , Curva ROC , Valores de Referência , Estudos Retrospectivos , Sensibilidade e Especificidade , Estatísticas não Paramétricas
16.
Med Sci Monit ; 25: 5920-5928, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31393860

RESUMO

BACKGROUND The effect of foot orthoses in terms of kinematics and kinetics during walking could be affected on different geometrical designs. Therefore, the purpose of this study was to compare the biomechanical and clinical effects of 3 different insoles on rearfoot motion (RFM) and ankle joint moment parameters. MATERIAL AND METHODS Twenty eight university students with flexible flatfoot were recruited for this study, and each participant was asked to wear 3 different insoles: normal insole without arch support function, type A insole with only arch support function, and type B insole with both arch support and cushion pads for shock absorbing functions. Three-dimensional motion analysis was performed to compute the ranges and peak orientation angles of RFM and ankle joint moment parameters. RESULTS The type A and type B insoles exhibited significantly smaller peak everted position and evertor moment than the normal insole. Also, the type A insole showed significantly smaller range of rearfoot motion in the longitudinal axis and the length of MA (moment arm) in the mediolateral axis than the normal insole. CONCLUSIONS The use of the type A insole using arch support function was induced to promote a cautious gait pattern associated with a relatively lower potential risk compared to the normal insole. The type A and type B insoles could be important to positively reduce the possibility of injury. Also, the smaller length of MA in the type A insole might have a contribution to the decrease of ankle joint evertor moment.


Assuntos
Pé Chato/terapia , Caminhada/fisiologia , Articulação do Tornozelo/fisiopatologia , Fenômenos Biomecânicos/fisiologia , Feminino , Pé Chato/fisiopatologia , , Órtoses do Pé , Marcha , Humanos , Cinética , Articulação do Joelho/fisiopatologia , Masculino , Movimento (Física) , Movimento/fisiologia , Sapatos , Adulto Jovem
17.
Sensors (Basel) ; 19(16)2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31434320

RESUMO

Lower back pain is one of the most prevalent diseases in Western societies. A large percentage of European and American populations suffer from back pain at some point in their lives. One successful approach to address lower back pain is postural training, which can be supported by wearable devices, providing real-time feedback about the user's posture. In this work, we analyze the changes in posture induced by postural training. To this end, we compare snapshots before and after training, as measured by the Gokhale SpineTracker™. Considering pairs of before and after snapshots in different positions (standing, sitting, and bending), we introduce a feature space, that allows for unsupervised clustering. We show that resulting clusters represent certain groups of postural changes, which are meaningful to professional posture trainers.


Assuntos
Dor Lombar/reabilitação , Monitorização Fisiológica , Postura/fisiologia , Dispositivos Eletrônicos Vestíveis , Feminino , Humanos , Dor Lombar/fisiopatologia , Masculino , Movimento (Física) , Coluna Vertebral/fisiologia
18.
Phys Chem Chem Phys ; 21(34): 18699-18705, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31423504

RESUMO

Fully hydrated bilayers of monounsaturated palmitoyloleoylphosphatidylcholine (POPC) and diunsaturated dioleoylphosphatidylcholine (DOPC) lipids have low main phase transition temperatures (271 K for POPC and 253 K for DOPC). Two-pulse echo detected spectra, combined with continuous wave electron paramagnetic resonance spectroscopy, are employed to study the low-temperature lamellar phases of the POPC and DOPC unsaturated bilayers that are usually studied in the fluid state. Phosphatidylcholine spin-labeled at C-5 and C-16 carbon atom positions along the acyl chain were used and the temperature varied over the range 77-270 K. Segmental chain librational oscillations of small amplitude and with correlation time in the subnanosecond to nanosecond range are found in both membranes. The mean-square angular amplitude, α2, of librations increases with temperature, is larger close to the bilayer midplane than close to the first acyl chain segments, and is larger in diunsaturated than in monounsaturated bilayers. In the inner hydrocarbon region of both lipid matrices, α2 increases first slowly and linearly with temperature and then more rapidly, and a dynamical transition is detected in the range 190-210 K. Compared to dipalmitoylphosphatidylcholine bilayers of fully saturated symmetric chain lipids, the presence of double bonds in the acyl chain enhances the intensity of librational motion which is characterized by larger angular variations at the terminal methyl ends. These findings highlight biophysical properties of unsaturated bilayers in the frozen state, including a detailed characterization of segmental chain dynamics and the evidence of a dynamical transition that appears to be a generic feature in hydrated macromolecular systems. These results can also be relevant in regulating membrane physical properties and function at higher physiological temperatures.


Assuntos
Bicamadas Lipídicas/química , 1,2-Dipalmitoilfosfatidilcolina/química , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Cinética , Conformação Molecular , Movimento (Física) , Transição de Fase , Fosfatidilcolinas/química , Marcadores de Spin , Temperatura Ambiente , Termodinâmica
19.
Biosens Bioelectron ; 143: 111597, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442755

RESUMO

Marine pollution and monitoring have received more and more concern in recent years. Herein, a fully automatic whole-algae biosensor was designed for low-cost and fast detection of toxic contaminants in seawater. It consists of a digital microfluidic (DMF) diluter chip, an actuation element, a detector element, and a microalgae bioreporter. A feedback-control protocol based on charging-time compensation was introduced. It ensures precise actuation of the droplet with diverse salty concentrations and contents in the marine environment. The two-mixer cross-split dilution engine increases the accuracy of droplet dispensing and concentration diluting. By selecting motility of P. subcordiformis as the sensor signal, the developed biosensor showed good sensitivity and robustness for a wide range of salinity (10-37‰), temperature (0-25 °C), light levels (0-325 µmol photons m-2 s-1), and cell density factor (1.0-4.0). The biosensor responses were examined in the presence of copper, lead, phenol, and nonylphenol (NP). In all cases, toxic responses (i.e. dose-related inhibition of algal motion) were detected with the detection limits of 0.65  µmol.L-1, 1.90  µmol.L-1, 2.85 mmol.L-1, and 5.22  µmol.L-1 respectively. These results were obtained in a much shorter time (2 h for our biosensor vs. 24 h-10 d for growth inhibition test) and the data are consistent with previous classical studies. We thus developed a simple, rapid, and adaptable system for marine routine monitoring and early-warning detection for lab and on-site applications.


Assuntos
Técnicas Biossensoriais , Monitoramento Ambiental , Poluentes Ambientais/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Cobre/química , Cobre/isolamento & purificação , Poluentes Ambientais/química , Poluição Ambiental , Limite de Detecção , Microalgas/química , Microfluídica , Movimento (Física) , Água do Mar/química , Poluentes Químicos da Água/química
20.
Eur J Radiol ; 119: 108640, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31442928

RESUMO

PURPOSE: To investigate the relationships between imaging parameters derived from intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and HPV status in oropharyngeal squamous cell carcinoma (OPSCC). MATERIALS AND METHODS: 73 patients with a new diagnosis of OPSCC were enrolled in the present study. MRI including IVIM-DWI with nine b value (range 0-800 s/mm2) was acquired in all patients. Primary tumor (PT) and the largest metastatic lymph node (LN), if present, were volumetrically contoured and the tissue diffusion coefficient Dt, perfusion fraction f and perfusion-related diffusion coefficient D* were estimated by a bi-exponential fit. The apparent diffusion coefficient (ADC) was also estimated by a mono-exponential fit. The predictive power of the most relevant patient/tumor characteristics and image-based features in determining the HPV status was assessed. RESULTS: 67 PTs and 67 metastatic LNs were analyzed. Significant differences in ADC and Dt values among HPV-positive and HPV-negative patients were found for PTs (p = 0.003 and p < 0.001, respectively), while a trend toward significance in Dt was reported for LNs (p = 0.066). The perfusion-related parameters, f, D* and D*× f, were not related to HPV status. The best predictive model for HPV positivity was obtained combining alcohol intake and smoke habits with Dt values of PTs (accuracy = 80.8%, sensitivity = 85.7%, specificity = 64.7%). CONCLUSION: Significant correlations were found between IVIM-DWI and HPV status in OPSCCs. The perfusion-free diffusion coefficient, Dt, may better reflect the HPV-related tumor differences compared to ADC, whereas the perfusion-related parameters were not able to reliably discriminate HPV-positive from HPV-negative OPSCC.


Assuntos
Neoplasias Orofaríngeas/patologia , Infecções por Papillomavirus/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Idoso , Imagem de Difusão por Ressonância Magnética/métodos , Feminino , Humanos , Linfonodos/patologia , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Neoplasias Orofaríngeas/virologia , Papillomaviridae , Estudos Prospectivos , Sensibilidade e Especificidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/virologia
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