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1.
J Clin Ultrasound ; 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38813899

RESUMO

We present a case study detailing the occurrence of splenic lymphangioma in a 9-year-old girl. The multimodal imaging revealed a significant mass, a finding subsequently validated through histopathological examination. This case underscores the importance of considering splenic lymphangioma as a rare but notable differential diagnosis for solid masses observed in imaging studies.

3.
Nano Lett ; 23(21): 9683-9689, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37883804

RESUMO

The highly tunable band structure of the zero-energy Landau level (zLL) of bilayer graphene makes it an ideal platform for engineering novel quantum states. However, the zero-energy Landau level at high electric fields has remained largely unexplored. Here we present magnetotransport measurements of bilayer graphene in high transverse electric fields. We observe previously undetected Landau level crossings at filling factors ν = -2, 1, and 3 at high electric fields. These crossings provide constraints for theoretical models of the zero-energy Landau level and show that the orbital, valley, and spin character of the quantum Hall states at high electric fields is very different from low electric fields. At high E, new transitions between states at ν = -2 with different orbital and spin polarization can be controlled by the gate bias, while the transitions between ν = 0 → 1 and ν = 2 → 3 show anomalous behavior.

7.
Nano Lett ; 21(21): 9005-9011, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34694117

RESUMO

Monolayer WTe2 is predicted to be a quantum spin Hall insulator (QSHI), and its quantized edge transport has recently been demonstrated. However, one of the essential properties of a QSHI, spin-momentum locking of the helical edge states, has yet to be experimentally validated. Here, we measure and observe gate-controlled anisotropic magnetoresistance (AMR) in monolayer WTe2 devices. Electrically tuning the Fermi energy into the band gap, a large in-plane AMR is observed and the minimum of the in-plane AMR occurs when the applied magnetic field is perpendicular to the current direction. In line with the experimental observations, the theoretical predictions based on the band structure of monolayer WTe2 demonstrate that the AMR effect originates from spin-momentum locking in the helical edge states of monolayer WTe2. Our findings reveal that the spin quantization axis of the helical edge states in monolayer WTe2 can be precisely determined from AMR measurements.

8.
Med Image Anal ; 69: 101975, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33550007

RESUMO

The outbreak of COVID-19 around the world has caused great pressure to the health care system, and many efforts have been devoted to artificial intelligence (AI)-based analysis of CT and chest X-ray images to help alleviate the shortage of radiologists and improve the diagnosis efficiency. However, only a few works focus on AI-based lung ultrasound (LUS) analysis in spite of its significant role in COVID-19. In this work, we aim to propose a novel method for severity assessment of COVID-19 patients from LUS and clinical information. Great challenges exist regarding the heterogeneous data, multi-modality information, and highly nonlinear mapping. To overcome these challenges, we first propose a dual-level supervised multiple instance learning module (DSA-MIL) to effectively combine the zone-level representations into patient-level representations. Then a novel modality alignment contrastive learning module (MA-CLR) is presented to combine representations of the two modalities, LUS and clinical information, by matching the two spaces while keeping the discriminative features. To train the nonlinear mapping, a staged representation transfer (SRT) strategy is introduced to maximumly leverage the semantic and discriminative information from the training data. We trained the model with LUS data of 233 patients, and validated it with 80 patients. Our method can effectively combine the two modalities and achieve accuracy of 75.0% for 4-level patient severity assessment, and 87.5% for the binary severe/non-severe identification. Besides, our method also provides interpretation of the severity assessment by grading each of the lung zone (with accuracy of 85.28%) and identifying the pathological patterns of each lung zone. Our method has a great potential in real clinical practice for COVID-19 patients, especially for pregnant women and children, in aspects of progress monitoring, prognosis stratification, and patient management.


Assuntos
COVID-19/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Aprendizado de Máquina , Masculino , Pessoa de Meia-Idade , SARS-CoV-2 , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X , Ultrassonografia , Adulto Jovem
9.
Sci Adv ; 5(7): eaaw0409, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31281884

RESUMO

With no requirements for lattice matching, van der Waals (vdW) ferromagnetic materials are rapidly establishing themselves as effective building blocks for next-generation spintronic devices. We report a hitherto rarely seen antisymmetric magnetoresistance (MR) effect in vdW heterostructured Fe3GeTe2 (FGT)/graphite/FGT devices. Unlike conventional giant MR (GMR), which is characterized by two resistance states, the MR in these vdW heterostructures features distinct high-, intermediate-, and low-resistance states. This unique characteristic is suggestive of underlying physical mechanisms that differ from those observed before. After theoretical calculations, the three-resistance behavior was attributed to a spin momentum locking induced spin-polarized current at the graphite/FGT interface. Our work reveals that ferromagnetic heterostructures assembled from vdW materials can exhibit substantially different properties to those exhibited by similar heterostructures grown in vacuum. Hence, it highlights the potential for new physics and new spintronic applications to be discovered using vdW heterostructures.

10.
Sci Adv ; 5(7): eaax5080, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31281902

RESUMO

Coexistence of reversible polar distortions and metallicity leading to a ferroelectric metal, first suggested by Anderson and Blount in 1965, has so far remained elusive. Electrically switchable intrinsic electric polarization, together with the direct observation of ferroelectric domains, has not yet been realized in a bulk crystalline metal, although incomplete screening by mobile conduction charges should, in principle, be possible. Here, we provide evidence that native metallicity and ferroelectricity coexist in bulk crystalline van der Waals WTe2 by means of electrical transport, nanoscale piezoresponse measurements, and first-principles calculations. We show that, despite being a Weyl semimetal, WTe2 has switchable spontaneous polarization and a natural ferroelectric domain structure at room temperature. This new class of materials has tantalizing potential for functional nanoelectronics applications.

11.
Exp Biol Med (Maywood) ; 244(7): 602-611, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30947537
12.
Ultrasound Q ; 35(1): 61-67, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30601439

RESUMO

We developed a method to create customizable phantoms suitable for endocavitary imaging and interventional research, based on the fabrication of an acrylic phantom mold, and development of a phantom matrix composed of gelatin, agar, graphite particles, and propanol. Our phantom was mechanically stable, easily fabricated, and highly adjustable, and its ultrasound (US) and magnetic resonance imaging (MRI) scans showed the qualification for the procedure guidance compared with the human prostate image using the same US system. To test the feasibility of the phantom for the research, the seeds placement guided by MRI/US fusion was performed, and the overall test error (distance from the seed center to the virtual lesion center in olives) was 2.59 ± 0.59 mm. We have created a simple, low-cost, configurable, gelatin-based phantom and tested its feasibility for simulating endorectal interventional US procedures. The design of the phantom mold and matrix is likely to be useful to the broader medical training community, and the preliminary data from the experiment of MRI/US-guided seeds placement showed its potential to test the clinical hypothesis in US research.


Assuntos
Imageamento por Ressonância Magnética/métodos , Imagem Multimodal/métodos , Imagens de Fantasmas , Próstata/diagnóstico por imagem , Ultrassonografia de Intervenção/métodos , Estudos de Viabilidade , Gelatina , Humanos , Masculino , Radiologia Intervencionista/métodos , Ultrassonografia/métodos
13.
Ultrasound Med Biol ; 45(4): 913-920, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30655110

RESUMO

To evaluate the value of pre-stenting and early post-stenting (<1 mo) duplex ultrasound parameters in predicting significant in-stent restenosis (ISR), we matched significant ISR patients 1:1 with controls without ISR in pre-stenting and early post-stenting (<1 mo) periods, respectively, using propensity score matching. Duplex ultrasound parameters, such as renal length difference between non-lesion side and lesion side within patient, trans-lesion peak systolic velocity and renal aortic ratio, were compared between cases and controls, and the area under the receiver operating characteristic curve (AUROC) was charted to predict ISR. After propensity score matching, 28 cases were matched in the pre-stenting period and 16 cases in the early post-stenting time period. Pre-stenting renal length difference, early post-stenting peak systolic velocity and renal aortic ratio showed significant differences in case-control comparisons. Early post-stenting peak systolic velocity (AUROC: 0.826, cutoff: 141 cm/s) and renal aortic ratio (AUROC: 0.770, cutoff: 1.75) performed well in predicting significant ISR and may serve as non-invasive markers in ISR surveillance.


Assuntos
Falha de Prótese , Obstrução da Artéria Renal/diagnóstico por imagem , Stents , Ultrassonografia Doppler Dupla/métodos , Idoso , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Pontuação de Propensão , Recidiva , Artéria Renal/diagnóstico por imagem , Artéria Renal/fisiopatologia , Obstrução da Artéria Renal/fisiopatologia , Reprodutibilidade dos Testes , Estudos Retrospectivos
14.
J Mol Cell Cardiol ; 123: 139-149, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30227118

RESUMO

Disruption of carotid vulnerable atherosclerotic plaque is responsible for acute ischemic stroke (AIS) and the early detection and intervention approach are greatly limited. Undertaking a microarray of microRNAs (miRNAs) in the plasma of AIS patients with carotid vulnerable plaques, miR-23a-5p was markedly elevated and was positively correlated with the plaque progression and vulnerability. Correspondingly, we found that miR-23a-5p expression was significantly increased in both plasma and macrophages from atherosclerosis mice. Bioinformatics analysis and in vitro knockdown experiments identified that ATP-binding cassette transporter A1/G1 as a novel target of miR-23a-5p. Luciferase reporter assays showed that miR-23a-5p repressed the 3' untranslated regions (UTR) activity of ABCA1/G1. Moreover, functional analyses demonstrated that transfection of miR-23a-5p inhibitor enhanced cholesterol efflux and decreased foam cell formation through upregulating ABCA1/G1 expression levels. Furthermore, long term in vivo systemically delivered miR-23a-5p antagomir significantly increased ABCA1/G1 expression in the aorta of ApoE-/- mice. Importantly, the miR-23a-5p antagomir therapy significantly reduced atherosclerosis progression and promoted plaque stability. Our observations indicate that miR-23a-5p promotes macrophage-derived foam cell formation and might be a key regulator contributing to atherosclerotic plaque progression and vulnerability.


Assuntos
Transportador 1 de Cassete de Ligação de ATP/genética , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Macrófagos/metabolismo , MicroRNAs/genética , Placa Aterosclerótica/genética , Placa Aterosclerótica/metabolismo , Regiões 3' não Traduzidas , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Modelos Animais de Doenças , Progressão da Doença , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Knockout , Modelos Biológicos , Placa Aterosclerótica/patologia , Células RAW 264.7 , Interferência de RNA
15.
Ultrasound Med Biol ; 44(11): 2209-2222, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30143339

RESUMO

We evaluated variation in fibrosis staging caused by depth, pre-load force and measurement off-axis distance on different ultrasound shear wave elastography (SWE) systems prospectively in 20 patients with diffuse liver disease. Shear wave speed (SWS) was measured with transient elastography, acoustic radiation force impulse (ARFI) and 2-D shear wave elastography (SWE). ARFI and 2-D-SWE measurements were obtained at different depths (3, 5 and 7 cm), with different pre-load forces (4, 7 and 10N and variable) and at 0, 2 and 4cm off the central axis of the transducer. A single, blinded pathologist staged fibrosis using the METAVIR system (F0-F4). Area under the receiver operating characteristic curve was charted to differentiate significant fibrosis (F ≥ 2). Depth was the only factor found to influence ARFI-derived values; no acquisition factors were found to affect 2-D-SWE SWS values. ARFI and 2-D-SWE for diagnosis of significant fibrosis at a depth of 7cm along the central axis had good diagnostic performance (areas under the receiver operating characteristic curve: 0.92 and 0.82, respectively), comparable to that of transient elastography. Further investigation of this finding will likely be of interest.


Assuntos
Técnicas de Imagem por Elasticidade/instrumentação , Técnicas de Imagem por Elasticidade/métodos , Cirrose Hepática/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Fígado/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Transdutores , Adulto Jovem
16.
ACS Appl Mater Interfaces ; 10(26): 22348-22355, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-29882406

RESUMO

Magnetic materials with large magnetic anisotropy are essential for workaday applications such as permanent magnets and magnetic data storage. There is widespread interest in finding efficient ways of controlling magnetic anisotropy, among which strain control has proven to be a very powerful technique. Here, we demonstrate the strain-mediated magnetic anisotropy in SrCoO3-δ thin film, a perovskite oxide that is metallic and adopts a cubic structure at δ ≤ 0.25. We find that the easy-magnetization axis in SrCoO3-δ can be rotated by 90° upon application of moderate epitaxial strains ranging from -1.2 to +1.8%. The magnetic anisotropy in compressive SrCoO3-δ thin films is huge, as shown by magnetic hysteresis loops rendering an anisotropy energy density of ∼106 erg/cm3. The local variance in magnetic force microscopy upon temperature and magnetic field reveals that the evolution of magnetic domains in the SCO thin film is strongly dependent on magnetic anisotropy.

17.
Urology ; 119: 23-31, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29730256

RESUMO

We map out a typical prostate cancer care pathway through discussion of updates on modern imaging. Multiparametric magnetic resonance imaging is the most sensitive and specific imaging tool for diagnosis and local staging, but transrectal ultrasound remains the most widely used technique for prostate biopsy guidance. Computed tomography and bone scan are useful in initial staging and recurrence detection. Novel imaging techniques in ultrasound elastography and multiparametric magnetic resonance imaging allow for increased lesion detection sensitivity and have the potential to enhance biopsy, while the development of new positron emission tomography radiotracers has great promise for improved detection of local and metastatic disease in patients with biochemical recurrence.


Assuntos
Neoplasias da Próstata/diagnóstico por imagem , Procedimentos Clínicos , Humanos , Biópsia Guiada por Imagem , Masculino , Neoplasias da Próstata/patologia , Neoplasias da Próstata/terapia
18.
Ultrasound Med Biol ; 44(5): 919-929, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29530434

RESUMO

This meta-analysis aimed to compare the diagnostic performance of contrast-enhanced ultrasound (CEUS), conventional ultrasound (US) combined with CEUS (US + CEUS) and US for distinguishing breast lesions. From thorough literature research, studies that compared the diagnostic performance of CEUS versus US or US + CEUS versus US, using pathology results as the gold standard, were included. A total of 10 studies were included, of which 9 compared the diagnostic performance of CEUS and US, and 5 studies compared US + CEUS and US. In those comparing CEUS versus US, the pooled sensitivity was 0.93 (95% CI: 0.91-0.95) versus 0.87 (95% CI: 0.85-0.90) and pooled specificity was 0.86 (95% CI: 0.84-0.88) versus 0.72 (95% CI: 0.69-0.75). In studies comparing US + CEUS versus US, the pooled sensitivity was 0.94 (95% CI: 0.92-0.96) versus 0.87 (95% CI: 0.84-0.90) and pooled specificity was 0.86 (95% CI: 0.82-0.89) versus 0.80 (95% CI: 0.76-0.84). In terms of diagnosing breast malignancy, areas under the curve of the summary receiver operating characteristic (of both CEUS (p = 0.003) and US + CEUS (p = 0.000) were statistically higher than that of US. Both CEUS alone and US + CEUS had better diagnostic performance than US in differentiation of breast lesions, and US + CEUS also had low negative likelihood ratio.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Meios de Contraste , Aumento da Imagem/métodos , Ultrassonografia/métodos , Mama/diagnóstico por imagem , Diagnóstico Diferencial , Feminino , Humanos , Reprodutibilidade dos Testes
19.
J Med Ultrason (2001) ; 45(2): 251-259, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28905143

RESUMO

PURPOSE: This study aimed at evaluating the diagnostic performance of quantitative shear wave elastography (SWE) in differentiating metastatic cervical lymph nodes from benign nodes in patients with thyroid nodules. METHODS: One hundred and forty-one cervical lymph nodes from 39 patients with thyroid nodules that were diagnosed as papillary thyroid cancer had been imaged with SWE. The shear elasticity modulus, which indicates the stiffness of the lymph nodes, was measured in terms of maximum shear elasticity modulus (maxSM), minimum shear elasticity modulus (minSM), mean shear elasticity modulus (meanSM), and standard deviation (SD) of the shear elasticity modulus. RESULTS: All the patients underwent thyroid surgery, 50 of the suspicious lymph nodes were resected, and 91 lymph nodes were followed up for 6 months. The maxSM value, minSM value, meanSM value, and SD value of the metastatic lymph nodes were significantly higher than those of the benign nodes. The area under the curve of the maxSM value, minSM value, meanSM value, and SD value were 0.918, 0.606, 0.865, and 0.915, respectively. CONCLUSIONS: SWE can differentiate metastasis from benign cervical lymph nodes in patients with thyroid nodules, and the maxSM, meanSM, and SD may be valuable quantitative indicators for characterizing cervical lymph nodes.


Assuntos
Carcinoma Papilar/diagnóstico por imagem , Técnicas de Imagem por Elasticidade/métodos , Linfonodos/diagnóstico por imagem , Pescoço/diagnóstico por imagem , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Nódulo da Glândula Tireoide/diagnóstico por imagem , Adolescente , Adulto , Idoso , Carcinoma Papilar/patologia , Módulo de Elasticidade , Feminino , Humanos , Linfonodos/patologia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Pescoço/patologia , Sensibilidade e Especificidade , Câncer Papilífero da Tireoide , Neoplasias da Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/patologia , Adulto Jovem
20.
Medicine (Baltimore) ; 96(44): e8420, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29095277

RESUMO

RATIONALE: Parathyroid carcinoma is a rare endocrine malignancy. Acute pancreatitis as an initial manifestation of parathyroid carcinoma has been rarely reported. PATIENT CONCERNS: A 22-year-old woman was admitted to emergency room with a sudden attack of severe epigastric pain. DIAGNOSES: Acute pancreatitis was diagnosed as elevated levels of serum amylase. During the work-up for acute pancreatitis, patient's abnormally increased serum calcium and bones destruction revealed by abdominal computed tomography (CT) scan raised the suspicion of hyperparathyroidism or malignancy. Elevated serum parathyroid hormone (PTH) levels, parathyroid ultrasound and scintigraphy gave rise to the diagnosis of primary hyperparathyroidism (PHPT) due to a left parathyroid tumor. INTERVENTIONS: The patient was given a complete tumor excision. After the surgery, parathyroid carcinoma with capsular and vascular invasion was confirmed histologically. A second surgery was then performed, including resection of the ipsilateral thyroid lobe and anterior cervical nodes. OUTCOMES: Serum calcium and PTH levels returned to normal postoperatively. LESSONS: Acute pancreatitis accompanied with hypercalcemia should always raise the suspicion of PHPT. The spicule sign, which always suggests the infiltrating pattern growth of tumor, was neglected at first and was observed during a second review of the ultrasound images postoperatively. This specific feature may be predictive for the preoperative diagnosis of parathyroid carcinoma or at least suspicion of malignancy.


Assuntos
Hiperparatireoidismo Primário/etiologia , Pancreatite/etiologia , Neoplasias das Paratireoides/complicações , Doença Aguda , Amilases/sangue , Cálcio/sangue , Feminino , Humanos , Hiperparatireoidismo Primário/sangue , Hiperparatireoidismo Primário/diagnóstico por imagem , Pancreatite/sangue , Pancreatite/diagnóstico por imagem , Glândulas Paratireoides/diagnóstico por imagem , Hormônio Paratireóideo/sangue , Neoplasias das Paratireoides/sangue , Neoplasias das Paratireoides/diagnóstico por imagem , Cintilografia , Ultrassonografia , Adulto Jovem
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