Postpartum two- and three-dimensional ultrasound evaluation of anal sphincter complex in women with obstetric anal sphincter injury.

Science.gov (United States)

Ros, C; Martínez-Franco, E; Wozniak, M M; Cassado, J; Santoro, G A; Elías, N; López, M; Palacio, M; Wieczorek, A P; Espuña-Pons, M

2017-04-01

To compare the sensitivity and specificity of two- (2D) and three- (3D) dimensional transperineal ultrasound (TPUS) and 3D endovaginal ultrasound (EVUS) with the gold standard 3D endoanal ultrasound (EAUS) in detecting residual defects after primary repair of obstetric anal sphincter injuries (OASIS). External (EAS) and internal (IAS) anal sphincters were evaluated by the four ultrasound modalities in women with repaired OASIS. 2D-TPUS was evaluated in real-time, whereas 3D-TPUS, 3D-EVUS and 3D-EAUS volumes were evaluated offline by six blinded readers. The presence/absence of any tear in EAS or IAS was recorded and defects were scored according to the Starck system. Sensitivity, specificity and predictive values were calculated, using 3D-EAUS as reference standard. Inter- and intraobserver analyses were performed for all 3D imaging modalities. Association between patients' symptoms (Wexner score) and ultrasound findings (Starck score) was calculated. Images from 55 patients were analyzed. Compared with findings on 3D-EAUS, the agreement for EAS evaluation was poor for 3D-EVUS (κ = 0.01), fair for 2D-TPUS (κ = 0.30) and good for 3D-TPUS (κ = 0.73). The agreement for IAS evaluation was moderate for both 3D-EVUS (κ = 0.41) and 2D-TPUS (κ = 0.52) and good for 3D-TPUS (κ = 0.66). Good intraobserver (3D-EAUS, κ = 0.73; 3D-TPUS, κ = 0.78) and interobserver (3D-EAUS, κ = 0.68; 3D-TPUS, κ = 0.60) agreement was reported. Significant association between Starck and Wexner scores was found only for 3D-EAUS (Spearman's rho = 0.277, P = 0.04). 2D-TPUS and 3D-EVUS are not accurate modalities for the assessment of anal sphincters after repair of OASIS. 3D-TPUS shows good agreement with the gold standard 3D-EAUS and a high sensitivity in detecting residual defects. It, thus, has potential as a screening tool after primary repair of OASIS. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG

Three-dimensional ultrasound strain imaging of skeletal muscles

NARCIS (Netherlands)

Gijsbertse, Kaj; Sprengers, Andre M.; Nillesen, Maartje; Hansen, Hendrik H.G.; Verdonschot, Nico; De Korte, Chris L.

2015-01-01

Muscle contraction is characterized by large deformation and translation, which requires a multi-dimensional imaging modality to reveal its behavior. Previous work on ultrasound strain imaging of the muscle contraction was limited to 2D and bi-plane techniques. In this study, a three-dimensional

[Two- and three-dimensional power Doppler ultrasound in the follow-up of placenta accreta treated conservatively].

Science.gov (United States)

Roulot, A; Barranger, E; Morel, O; Soyer, P; Héquet, D

2015-02-01

To determinate the potential of 2D and 3D-ultrasound in the follow-up of patients with placenta accreta treated conservatively. Seven patients with placenta accreta treated conservatively during June 2007 and September 2009 were included. The follow-up consisted in clinical examination and 2D/3D-ultrasound once a month. Criteria studied included clinical outcome, echogenicity at 2D-ultrasound, vascularisation at colour Doppler, Mean Grey at 3D-ultrasound and vascularisation, flow and perfusion index. Seven women with invasive placenta (3 placentas accreta and 2 percreta) were studied. The mean follow-up was 228 days [75-369]. Mean delay for complete elimination of residual placenta was 280 days [120-365]. The two main results were: presence of an increased anechogenicpart in residual placenta before complete resorption for all patients; a systematic and concomitant stop of genital haemorrhage and vascularisation at colour Doppler. High degrees of variability in parameters measured at 3D-ultrasound were observed between patients so that correlations with clinical outcome were found. Long and regular follow-up is essential after conservative management but the role of 3D-ultrasound compared to 2D-ultrasound was not demonstrated in this study. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Two-Dimensional (2D Slices Encryption-Based Security Solution for Three-Dimensional (3D Printing Industry

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Giao N. Pham

2018-05-01

Full Text Available Nowadays, three-dimensional (3D printing technology is applied to many areas of life and changes the world based on the creation of complex structures and shapes that were not feasible in the past. But, the data of 3D printing is often attacked in the storage and transmission processes. Therefore, 3D printing must be ensured security in the manufacturing process, especially the data of 3D printing to prevent attacks from hackers. This paper presents a security solution for 3D printing based on two-dimensional (2D slices encryption. The 2D slices of 3D printing data is encrypted in the frequency domain or in the spatial domain by the secret key to generate the encrypted data of 3D printing. We implemented the proposed solution in both the frequency domain based on the Discrete Cosine Transform and the spatial domain based on geometric transform. The entire 2D slices of 3D printing data is altered and secured after the encryption process. The proposed solution is responsive to the security requirements for the secured storage and transmission. Experimental results also verified that the proposed solution is effective to 3D printing data and is independent on the format of 3D printing models. When compared to the conventional works, the security and performance of the proposed solution is also better.

Quantitative measurement of total cerebral blood flow using 2D phase-contrast MRI and doppler ultrasound

Energy Technology Data Exchange (ETDEWEB)

Seo, Keum Soo; Choi, Sun Seob; Lee, Young Il [Dong-A Univ., College of Medicine, Busan (Korea, Republic of)

2001-12-01

To compare of quantitative measurement of the total cerebral blood flow using two-dimensional phase-contrast MR imaging and Doppler ultrasound. In 16 volunteers (mean age, 26 years; mean body weight, 66 kg) without abnormal medical histories, two-dimensional phase-contrast MR imaging was performed at the level of the C2-3 inter vertebral disc for flow measurement of the internal carotid arteries and the vertebral arteries. Volume flow measurements using Doppler ultrasound were also performed at the internal carotid arteries 2cm above the carotid bifurcation, and at the vertebral arteries at the level of the upper pole of the thyroid gland. Flows in the four vessels measured by the two methods were compared using Wilcoxon's correlation analysis and the median score. Total cerebral blood flows were calculated by summing these four vessel flows, and mean values for the 16 volunteers were calculated. Cerebral blood flows measured by 2-D phase-contrast MR imaging and Doppler ultrasounds were 233 and 239 ml/min in the right internal carotid artery, 250 and 248 ml/min in the left internal carotid artery, 62 and 56 ml/min in the right vertebral artery, and 83 and 68 ml/min in the left vertebral artery. Correlation coefficients of the blood flows determined by the two methods were 0.48, 0.54, 0.49, and 0.62 in each vessel, while total cerebral blood flows were 628{+-}68 (range, 517 to 779) ml/min and 612{+-}79 (range, 482 to 804)ml/min, respectively. Total cerebral blood flow was easily measured using 2-D phase-contrast MR imaging and Doppler ultrasound, and the two noninvasive methods can therefore be used clinically for the measurement of total cerebral blood flow.

Ovarian morphology in polycystic ovary syndrome: estimates from 2D and 3D ultrasound and magnetic resonance imaging and their correlation to anti-Müllerian hormone.

Science.gov (United States)

Nylander, Malin; Frøssing, Signe; Bjerre, Anne H; Chabanova, Elizaveta; Clausen, Helle V; Faber, Jens; Skouby, Sven O

2017-08-01

Background Due to improved ultrasound scanners, new three-dimensional (3D) modalities, and novel Anti-Müllerian hormone (AMH)-assays, the ultrasound criteria for polycystic ovarian morphology are under debate and the appropriate thresholds are often requested. Purpose To quantify the differences in estimates of ovarian volume and antral follicle count (AFC) from two-dimensional (2D) and 3D transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI). Material and Methods A cross-sectional study on 66 overweight women with polycystic ovary syndrome (PCOS) according to Rotterdam criteria. Ovarian volume and AFC were estimated from MRI, 2D TVUS, and 3D TVUS, and serum AMH levels were assessed. Bland-Altman statistics were used for comparison. Results Participants had a median age of 29 years (age range, 19-44 years) with a mean BMI of 32.7 kg/m 2 (SD 4.5). Ovarian volume from 2D TVUS was 1.48 mL (95% confidence interval [CI], 0.94-2.03; P ovarian volume and AFC as compared with 3D TVUS and MRI. Serum AMH correlated best with AFC from 3D TVUS, followed by MRI and 2D TVUS. The advantage of 3D TVUS might be of minor clinical importance when diagnosing PCOS, but useful when the actual AFC are of interest, e.g. in fertility counseling and research.

Antenatal diagnosis of anophthalmia by three-dimensional ultrasound: a novel application of the reverse face view.

Science.gov (United States)

Wong, H S; Parker, S; Tait, J; Pringle, K C

2008-07-01

The prenatal diagnosis of anophthalmia can be made on the demonstration of absent eye globe and lens on the affected side(s) on two-dimensional ultrasound examination, but when the fetal head position is unfavorable three-dimensional (3D) ultrasound may reveal additional diagnostic sonographic features, including sunken eyelids and small or hypoplastic orbit on the affected side(s). We present two cases of isolated anophthalmia diagnosed on prenatal ultrasound examination in which 3D ultrasound provided additional diagnostic information. The reverse face view provides valuable information about the orbits and the eyeballs for prenatal diagnosis and assessment of anophthalmia.

Three dimensional (3d) transverse oscillation vector velocity ultrasound imaging

DEFF Research Database (Denmark)

2013-01-01

as to traverse a field of view, and receive circuitry (306) configured to receive a two dimensional set of echoes produced in response to the ultrasound signal traversing structure in the field of view, wherein the structure includes flowing structures such as flowing blood cells, organ cells etc. A beamformer...

Two-dimensional power Doppler-three-dimensional ultrasound imaging of a cesarean section dehiscence with utero-peritoneal fistula: a case report

Directory of Open Access Journals (Sweden)

Royo Pedro

2009-01-01

Full Text Available Abstract Introduction An imaging diagnosis after an iterative cesarean delivery is reviewed demonstrating a fine ultrasound-pathologic correlation. Case presentation A 33-year-old woman (G3, P3 presented referring intense dysmenorrhea and intermenstrual spotting since her third cesarean delivery, 1 year before. A cesarean section dehiscence with utero-peritoneal fistula was diagnosed by transvaginal ultrasound. Conclusion We can conclude that transvaginal two-dimensional power Doppler and three-dimensional ultrasound are highly accurate in detecting cesarean section dehiscence and uterine fistula.

2D/3D/4D ULTRASOUND IN INFERTILITY MANAGEMENT

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Uršula Reš-Muravec

2018-02-01

Ultrasound in infertility diagnostics: Ultrasound is used for examination of uterus, tubes, ovaries and peritoneal cause of infertility. It can be used in different menstrual phases: proliferative, periovulatory and secretory phase. Examination of uterus: A 2D scan can measure the size of the uterus (length, width and depth and a 2D flow (colour and power doppler. With 3D technology we can measure the whole volume with VOCAL (virtual organ computer-aided analysis and 3D circulation with the index (VI – vascular index, FI – flow index and VFI – vascular flow index in the uterus. A 2D scan can help us define uterine malformations, fibroids and adenomyosis to a certain extent. However, a 3D scan offers more accurate diagnosis of these malformations. Endometrium is examined separately. With 2D the width is measured and morphology and focal lesions (polyp, fibroids, adhesions are examined. With 3D the real sagital plane for the width measurement can be defined . We can measure the volume of endometrium and subendometrium and 3D circulation in endometrium and subendometrium. The FIS (f luid instlation sonography is very useful when examining the endometrium; saline or gel can be used for uterine instalation. We can measure and define the position of the structures in the endometrium more accurately when they are surrouned by saline or gel. We can view these structures with a surface view, similar to the one used for hysteroscopy. With this information we can explain the pathology to the patient and easily plan the surgical procedures. Examination of the tubes: With 2D US we can see the tubes in the pelvis only if there are dilatations, but sometimes it is difficult to distinguish them from the neighbouring forma- tions. With a 3D ultrasound we can define the shape and continuity of the tube and we can view the tube from different angles (inversion mode. Different contrast media are used for determining tubal patency. Tubal patency can be diagnosed with 2D Hy

Nucleation front instability in two-dimensional (2D) nanosheet gadolinium-doped cerium oxide (CGO) formation

DEFF Research Database (Denmark)

Marani, Debora; Moraes, Leticia Poras Reis; Gualandris, Fabrizio

2018-01-01

Herein we report for the first time the synthesis of ceramic–organic three-dimensional (3D) layered gadolinium-doped cerium oxide (Ce1−XGdXO2−δ, CGO) and its exfoliation into two-dimensional (2D) nanosheets. We adopt a water-based synthetic route via a homogenous precipitation approach at low...... temperatures (10–80 °C). The reaction conditions are tuned to investigate the effects of thermal energy on the final morphology. A low temperature (40 °C) morphological transition from nanoparticles (1D) to two-dimensional (2D) nanosheets is observed and associated with a low thermal energy transition of ca. 2.......6 kJ mol−1. For the 3D-layered material, exfoliation experiments are conducted in water/ethanol solutions. Systems at volume fractions ranging from 0.15 to 0.35 are demonstrated to promote under ultrasonic treatment the delamination into 2D nanosheets....

Preoperative prediction of lymph node metastasis and deep stromal invasion in women with invasive cervical cancer: prospective multicenter study using 2D and 3D ultrasound.

Science.gov (United States)

Pálsdóttir, K; Fischerova, D; Franchi, D; Testa, A; Di Legge, A; Epstein, E

2015-04-01

To determine how various objective two-dimensional (2D) and three-dimensional (3D) ultrasound parameters allow prediction of deep stromal tumor invasion and lymph node involvement, in comparison to subjective ultrasound assessment, in women scheduled for surgery for cervical cancer. This was a prospective multicenter trial including 104 women with cervical cancer at FIGO Stages IA2-IIB, verified histologically. Patients scheduled for surgery underwent a preoperative ultrasound examination. The value of various 2D (size, color score) and 3D (volume, vascular indices) ultrasound parameters was compared to that of subjective assessment in the prediction of deep stromal tumor invasion and lymph node involvement. Histology obtained from radical hysterectomy or trachelectomy and pelvic lymphadenectomy was considered as the gold standard for assessment. All women underwent pelvic lymphadenectomy, with 99 (95%) undergoing subsequent radical surgery; five underwent only pelvic lymphadenectomy because of the presence of a positive sentinel lymph node. Women with deep stromal invasion or lymph node involvement had significantly larger tumors (diameter and volume) but there was no correlation with vascular indices measured on 3D ultrasound. Subjective evaluation was superior (AUC, 0.93; sensitivity, 90.5%; specificity, 97.2%) in the prediction of deep stromal invasion when compared to any objective measurement technique, with maximal tumor diameter at 20.5-mm cut-off (AUC, 0.83; sensitivity, 90.5%; specificity, 61.1%) and 3D tumor volume at 9.1-mm(3) cut-off (AUC, 0.85; sensitivity, 79.4%; specificity, 83.3%) providing the best performance among the objective parameters. Both subjective assessment and objective measurements were poorly predictive of lymph node involvement. In women with cervical cancer, subjective ultrasound evaluation allowed better prediction of deep stromal invasion than did objective measurements; however, neither subjective evaluation nor objective

Monitoring Prostate Tumor Growth in an Orthotopic Mouse Model Using Three-Dimensional Ultrasound Imaging Technique

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Jie Ni

2016-02-01

Full Text Available Prostate cancer (CaP is the most commonly diagnosed and the second leading cause of death from cancer in males in USA. Prostate orthotopic mouse model has been widely used to study human CaP in preclinical settings. Measurement of changes in tumor size obtained from noninvasive diagnostic images is a standard method for monitoring responses to anticancer modalities. This article reports for the first time the usage of a three-dimensional (3D ultrasound system equipped with photoacoustic (PA imaging in monitoring longitudinal prostate tumor growth in a PC-3 orthotopic NODSCID mouse model (n = 8. Two-dimensional and 3D modes of ultrasound show great ability in accurately depicting the size and shape of prostate tumors. PA function on two-dimensional and 3D images showed average oxygen saturation and average hemoglobin concentration of the tumor. Results showed a good fit in representative exponential tumor growth curves (n = 3; r2 = 0.948, 0.955, and 0.953, respectively and a good correlation of tumor volume measurements performed in vivo with autopsy (n = 8, r = 0.95, P < .001. The application of 3D ultrasound imaging proved to be a useful imaging modality in monitoring tumor growth in an orthotopic mouse model, with advantages such as high contrast, uncomplicated protocols, economical equipment, and nonharmfulness to animals. PA mode also enabled display of blood oxygenation surrounding the tumor and tumor vasculature and angiogenesis, making 3D ultrasound imaging an ideal tool for preclinical cancer research.

Two-dimensional and three-dimensional ultrasonography for pregnancy diagnosis and antenatal fetal development in Beetal goats

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Kailash Kumar

2015-07-01

Full Text Available Aim: The objective of this study was to compare two-dimensional (2D and three-dimensional (3D study of the pregnant uterus and antenatal development of the fetus. Materials and Methods: 2D and 3D ultrasound were performed from day 20 to 120 of gestation, twice in week from day 20 to 60 and once in week from day 60 to 120 of gestation on six goats. The ultrasonographic images were obtained using Toshiba, Nemio-XG (Japan 3D ultrasound machine. Results: On the 20th day of gestation, earliest diagnosis of pregnancy was done. First 3D ultrasonographic image of the conceptus, through transabdominal approach, was obtained on day 24. On 39th day, clear pictures of conceptus, amniotic membrane, and umbilicus were seen. On 76th day of gestation, internal organs of fetus viz heart, kidney, liver, urinary bladder, and stomach were seen both in 2D and 3D images. 3D imaging showed better details of uterine structures and internal organs of the fetus. Conclusions: Comparing 3D images with 2D images, it is concluded that 2D was better in visualizing fluid while 3D images were better to view details of attachment of fetus with endometrium.

Principal Component Analysis Based Two-Dimensional (PCA-2D) Correlation Spectroscopy: PCA Denoising for 2D Correlation Spectroscopy

International Nuclear Information System (INIS)

Jung, Young Mee

2003-01-01

Principal component analysis based two-dimensional (PCA-2D) correlation analysis is applied to FTIR spectra of polystyrene/methyl ethyl ketone/toluene solution mixture during the solvent evaporation. Substantial amount of artificial noise were added to the experimental data to demonstrate the practical noise-suppressing benefit of PCA-2D technique. 2D correlation analysis of the reconstructed data matrix from PCA loading vectors and scores successfully extracted only the most important features of synchronicity and asynchronicity without interference from noise or insignificant minor components. 2D correlation spectra constructed with only one principal component yield strictly synchronous response with no discernible a asynchronous features, while those involving at least two or more principal components generated meaningful asynchronous 2D correlation spectra. Deliberate manipulation of the rank of the reconstructed data matrix, by choosing the appropriate number and type of PCs, yields potentially more refined 2D correlation spectra

Status for the two-dimensional Navier-Stokes solver EllipSys2D

DEFF Research Database (Denmark)

Bertagnolio, F.; Sørensen, Niels N.; Johansen, J.

2001-01-01

This report sets up an evaluation of the two-dimensional Navier-Stokes solver EllipSys2D in its present state. This code is used for blade aerodynamics simulations in the Aeroelastic Design group at Risø. Two airfoils are investigated by computing theflow at several angles of attack ranging from...

Inter-rater reliability in the classification of supraspinatus tendon tears using 3D ultrasound – a question of experience?

Directory of Open Access Journals (Sweden)

Giorgio Tamborrini

2016-09-01

Full Text Available Background: Three-dimensional (3D ultrasound of the shoulder is characterized by a comparable accuracy to two-dimensional (2D ultrasound. No studies investigating 2D versus 3D inter-rater reliability in the detection of supraspinatus tendon tears taking into account the level of experience of the raters have been carried out so far. Objectives: The aim of this study was to determine the inter-rater reliability in the analysis of 3D ultrasound image sets of the supraspinatus tendon between sonographer with different levels of experience. Patients and methods: Non-interventional, prospective, observational pilot study of 2309 images of 127 adult patients suffering from unilateral shoulder pain. 3D ultrasound image sets were scored by three raters independently. The intra-and interrater reliabilities were calculated. Results: There was an excellent intra-rater reliability of rater A in the overall classification of supraspinatus tendon tears (2D vs 3D κ = 0.892, pairwise reliability 93.81%, 3D scoring round 1 vs 3D scoring round 2 κ = 0.875, pairwise reliability 92.857%. The inter-rater reliability was only moderate compared to rater B on 3D (κ = 0.497, pairwise reliability 70.95% and fair compared to rater C (κ = 0.238, pairwise reliability 42.38%. Conclusions: The reliability of 3D ultrasound of the supraspinatus tendon depends on the level of experience of the sonographer. Experience in 2D ultrasound does not seem to be sufficient for the analysis of 3D ultrasound imaging sets. Therefore, for a 3D ultrasound analysis new diagnostic criteria have to be established and taught even to experienced 2D sonographers to improve reproducibility.

Three-dimensional Ultrasound in the Management of Abdominal Aortic Aneurysms

DEFF Research Database (Denmark)

Lowe, C B; Ghulam, Q; Bredahl, K

2016-01-01

Three-dimensional (3D) ultrasound is an evolving modality that may have numerous applications in the management of abdominal aortic aneurysms. Many vascular specialists will not be familiar with the different ways in which 3D vascular ultrasound data can be acquired nor how potential applications...

First trimester diagnosis of sirenomelia by 2D and 3D ultrasound.

Science.gov (United States)

Contu, Rossana; Zoppi, Maria A; Axiana, Carolina; Ibba, Rosa M; Monni, Giovanni

2009-01-01

A case of sirenomelia in a 27-year-old woman detected at 11 weeks 5 days of gestation is presented. It was suspected by two-dimensional sonography and color Doppler imaging. Three-dimensional ultrasound confirmed the final diagnosis. With detailed evaluation of the acquired volumes, valuable information was obtained about the anatomical as well as pathological features of the fetus. 2009 S. Karger AG, Basel.

Three-dimensional ultrasound. Early personal experience with a dedicated unit and literature review

International Nuclear Information System (INIS)

Cesarani, F.; Isolato, G.; Capello, S.; Bianchi, S.D.

1999-01-01

The authors report our preliminary clinical experience with three-dimensional ultrasound (3D US) in abdominal and small parts imaging, comparing the yield of 3D versus 2D US and the through a literature review [it

Two-dimensional Dirac fermions in thin films of C d3A s2

Science.gov (United States)

Galletti, Luca; Schumann, Timo; Shoron, Omor F.; Goyal, Manik; Kealhofer, David A.; Kim, Honggyu; Stemmer, Susanne

2018-03-01

Two-dimensional states in confined thin films of the three-dimensional Dirac semimetal C d3A s2 are probed by transport and capacitance measurements under applied magnetic and electric fields. The results establish the two-dimensional Dirac electronic spectrum of these states. We observe signatures of p -type conduction in the two-dimensional states as the Fermi level is tuned across their charge neutrality point and the presence of a zero-energy Landau level, all of which indicate topologically nontrivial states. The resistance at the charge neutrality point is approximately h /e2 and increases rapidly under the application of a magnetic field. The results open many possibilities for gate-tunable topological devices and for the exploration of novel physics in the zero-energy Landau level.

A Standardized Method for 4D Ultrasound-Guided Peripheral Nerve Blockade and Catheter Placement

Directory of Open Access Journals (Sweden)

N. J. Clendenen

2014-01-01

Full Text Available We present a standardized method for using four-dimensional ultrasound (4D US guidance for peripheral nerve blocks. 4D US allows for needle tracking in multiple planes simultaneously and accurate measurement of the local anesthetic volume surrounding the nerve following injection. Additionally, the morphology and proximity of local anesthetic spread around the target nerve is clearly seen with the described technique. This method provides additional spatial information in real time compared to standard two-dimensional ultrasound.

The Correlation Between the GFR and the Renal Dimensions in Glomerulopathy Patients: Comparison of 2D and 3D Ultrasound

International Nuclear Information System (INIS)

Kim, Gyoung Min; Lee, Hak Jong; Hwang, Sung Il; Chin, Ho Jun

2011-01-01

We wanted to determine the correlation between the renal length as measured on two dimensional (2D) ultrasonography (US) and the renal parenchymal volume as measured with a new three-dimensional (3D) volume probe ultrasound system. We also wanted to determine the correlation between the renal length or renal parenchymal volume and the glomerular filtration rate (GFR) in patients with glomerulopathy. From July 2007 to December 2007, 26 patients who were pathologically confirmed to have glomerulopathy by biopsy were enrolled. Renal length was measured with 2D US and the renal parenchymal volume was measured with 3D US just prior to biopsy. The GFR was obtained from the electronic medical records. Pearson's correlation coefficients were used to analyze the correlation between the renal length and the renal parenchymal volume, the correlation between the renal length and the GFR and the correlation between the renal parenchymal volume and the GFR. The renal length and the renal parenchymal volume showed strong positive correlation (r = 0.850, p = 0.0001). The correlation coefficient between the renal length and the GFR was 0.623 (p = 0.0007) and the correlation coefficient between the renal volume and the GFR was 0.590 (p = 0.0015). Both the renal length and renal parenchymal volume showed apparently positive correlations with the GFR in glomerulopathy patients. The renal length showed strong positive correlations with the renal parenchymal volume. Both the renal length and the renal parenchymal volume showed apparently positive correlations with the GFR in glomerulopathy patients. In glomerulopathy patients, the renal dimensions measured by ultrasound can reflect the status of the GFR, and the measurement of the 2D renal length could be sufficient for follow up. Further studies are needed to evaluate the role of 3D US for assessing patients with renal disease

Three dimensional ultrasound and hdlive technology as possible tools in teaching embryology.

Science.gov (United States)

Popovici, Razvan; Pristavu, Anda; Sava, Anca

2017-10-01

Embryology is an important subject in order to gain an understanding of medicine and surgery; however, sometimes students find the subject difficult to grasp and apply to clinical practice. Modern imaging techniques can be useful aids in teaching and understanding embryology. Imaging techniques have very rapidly evolved over the last few years, advancing from two- to three-dimensional (3D) ultrasound. HDlive is an innovative ultrasound technique that generates near-realistic images of the human fetus. In order to evince the capabilities of 3D ultrasound and HDlive technology in teaching embryology, we evaluated using this technique the normal evolution of the embryo and fetus from the fifth to eleventh week of amenorrhea. Our conclusion is that by yielding clear and impressive images, 3D ultrasound and HDlive could be useful tools in teaching embryology to medical students. Clin. Anat. 30:953-957, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Three-dimensional ultrasound in the diagnosis of Müllerian duct anomalies and concordance with magnetic resonance imaging.

Science.gov (United States)

Bermejo, C; Martínez Ten, P; Cantarero, R; Diaz, D; Pérez Pedregosa, J; Barrón, E; Labrador, E; Ruiz López, L

2010-05-01

To demonstrate the value of three-dimensional (3D) ultrasound in the diagnosis of uterine malformations and its concordance with magnetic resonance imaging (MRI). This study included 286 women diagnosed with uterine malformation by 3D ultrasound, having been referred to our clinics on suspicion of uterine malformation following clinical and/or conventional two-dimensional ultrasound examination. With the exception of three with intact hymen, patients underwent both bimanual examination and speculoscopy before and/or after sonography. MRI was performed in 65 cases. We analyzed the diagnostic concordance between the techniques in the study of uterine malformations. Using 3D ultrasound we diagnosed: one case with uterine agenesis; 10 with unicornuate uterus, four of which also underwent MRI; six with didelphic uterus, one of which had MRI; 45 with bicornuate uterus, 12 of which had MRI; 125 with septate uterus (18 with two cervices), 42 of which had MRI (six with two cervices); 96 with arcuate uterus, three of which had MRI; and three with diethylstilbestrol (DES) iatrogenic uterine malformations, all of which had MRI. Among the 65 which underwent MRI, the diagnosis was: four cases with unicornuate uterus, 10 with bicornuate uterus (two with two cervices), 45 with septate uterus (five with two cervices), three with arcuate uterus and three with DES-related uterine malformations. The concordance between 3D ultrasound and MRI was very good (kappa index, 0.880 (95% CI, 0.769-0.993)). Discrepancies in diagnosis between the two techniques occurred in four cases. There was very good concordance in the diagnosis of associated findings (kappa index, 0.878 (95% CI, 0.775-0.980)), this analysis identifying differences in two cases. There is a high degree of concordance between 3D ultrasound and MRI in the diagnosis of uterine malformations, the relationship between cavity and fundus being visualized equally well with both techniques. 3D ultrasound should be complemented by

MLESAC Based Localization of Needle Insertion Using 2D Ultrasound Images

Science.gov (United States)

Xu, Fei; Gao, Dedong; Wang, Shan; Zhanwen, A.

2018-04-01

In the 2D ultrasound image of ultrasound-guided percutaneous needle insertions, it is difficult to determine the positions of needle axis and tip because of the existence of artifacts and other noises. In this work the speckle is regarded as the noise of an ultrasound image, and a novel algorithm is presented to detect the needle in a 2D ultrasound image. Firstly, the wavelet soft thresholding technique based on BayesShrink rule is used to denoise the speckle of ultrasound image. Secondly, we add Otsu’s thresholding method and morphologic operations to pre-process the ultrasound image. Finally, the localization of the needle is identified and positioned in the 2D ultrasound image based on the maximum likelihood estimation sample consensus (MLESAC) algorithm. The experimental results show that it is valid for estimating the position of needle axis and tip in the ultrasound images with the proposed algorithm. The research work is hopeful to be used in the path planning and robot-assisted needle insertion procedures.

Spatial-temporal three-dimensional ultrasound plane-by-plane active cavitation mapping for high-intensity focused ultrasound in free field and pulsatile flow.

Science.gov (United States)

Ding, Ting; Hu, Hong; Bai, Chen; Guo, Shifang; Yang, Miao; Wang, Supin; Wan, Mingxi

2016-07-01

Cavitation plays important roles in almost all high-intensity focused ultrasound (HIFU) applications. However, current two-dimensional (2D) cavitation mapping could only provide cavitation activity in one plane. This study proposed a three-dimensional (3D) ultrasound plane-by-plane active cavitation mapping (3D-UPACM) for HIFU in free field and pulsatile flow. The acquisition of channel-domain raw radio-frequency (RF) data in 3D space was performed by sequential plane-by-plane 2D ultrafast active cavitation mapping. Between two adjacent unit locations, there was a waiting time to make cavitation nuclei distribution of the liquid back to the original state. The 3D cavitation map equivalent to the one detected at one time and over the entire volume could be reconstructed by Marching Cube algorithm. Minimum variance (MV) adaptive beamforming was combined with coherence factor (CF) weighting (MVCF) or compressive sensing (CS) method (MVCS) to process the raw RF data for improved beamforming or more rapid data processing. The feasibility of 3D-UPACM was demonstrated in tap-water and a phantom vessel with pulsatile flow. The time interval between temporal evolutions of cavitation bubble cloud could be several microseconds. MVCF beamformer had a signal-to-noise ratio (SNR) at 14.17dB higher, lateral and axial resolution at 2.88times and 1.88times, respectively, which were compared with those of B-mode active cavitation mapping. MVCS beamformer had only 14.94% time penalty of that of MVCF beamformer. This 3D-UPACM technique employs the linear array of a current ultrasound diagnosis system rather than a 2D array transducer to decrease the cost of the instrument. Moreover, although the application is limited by the requirement for a gassy fluid medium or a constant supply of new cavitation nuclei that allows replenishment of nuclei between HIFU exposures, this technique may exhibit a useful tool in 3D cavitation mapping for HIFU with high speed, precision and resolution

Three-dimensional vs. two-dimensional shear-wave elastography of the testes - preliminary study on a healthy collective.

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Marcon, J; Trottmann, M; Rübenthaler, J; D'Anastasi, M; Stief, C G; Reiser, M F; Clevert, D A

2016-01-01

Shear wave elastography (SWE) and its derivative Supersonic Shear Imaging (SSI) are newer techniques for the determination of tissue elasticity by measuring the velocity of generated shear waves (SWV), which correlates positively with tissue stiffness.The techniques are integrated into many modern ultrasound systems and have been examined in the evaluation of viscoelastic properties of different organ systems. Two-dimensional shear wave elastography (2D SWE) of the testes has been found to be a useful tool in recent studies which included the determination of standard values in healthy volunteers. Three-dimensional shear wave elastography (3D SWE) is the latest development in elastography and is made possible by generation of a multiplanar three-dimensional map via volumetric acquisition with a special ultrasound transducer. This technique allows the assessment of tissue elasticity in a three-dimensional, fully accessible organ map.The aim of this preliminary study was to both evaluate the feasibility of 3D SWE and to compare 2D and 3D SWE standard values in the testes of healthy subjects. We examined the testes of healthy male volunteers (n = 32) with a mean age of 51.06±17.75 years (range 25-77 years) by B-mode ultrasound, 2D and 3D SWE techniques in September of 2016. Volunteers with a history of testicular pathologies were excluded. For all imaging procedures the SL15-4 linear transducer (bandwidth 4-15 MHz) as well as the SLV16-4 volumetric probe (bandwidth 4-16 MHz) of the Aixplorer® ultrasound device (SuperSonic Imagine, Aix-en-Provence, France) were used. Seven regions of interest (ROI, Q-Box®) within the testes were evaluated for SWV using both procedures. SWV values were described in m/s. Results were statistically evaluated using univariateanalysis. Mean SWV values were 1.05 m/s for the 2D SWE and 1.12 m/s for the 3D SWE.Comparisons of local areas delivered no statistically significant differences (p = 0.11 to p = 0.66), except for

Two-trace two-dimensional (2T2D) correlation spectroscopy - A method for extracting useful information from a pair of spectra

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Noda, Isao

2018-05-01

Two-trace two-dimensional (2T2D) correlation spectroscopy, where a pair of spectra are compared as 2D maps by a form of cross correlation analysis, is introduced. In 2T2D, spectral intensity changes of bands arising from the same origin, which cannot change independently of each other, are synchronized. Meanwhile, those arising from different sources may and often do change asynchronously. By taking advantage of this property, one can distinguish and classify a number of contributing bands present in the original pair of spectra in a systematic manner. Highly overlapped neighboring bands originating from different sources can also be identified by the presence of asynchronous cross peaks, thus enhancing the apparent spectral resolution. Computational procedure to obtain 2T2D correlation spectra and their interpretation method, as well as an illustrative description of the basic concept in the vector phase space, are provided. 2T2D spectra may also be viewed as individual building blocks of the generalized 2D correlation spectra derived from a series of more than two spectral data. Some promising application potentials of 2T2D correlation and integration with established advanced 2D correlation techniques are discussed.

The Interobserver Variability and Diagnostic Performance of 3-Dimensional Breast Ultrasound

International Nuclear Information System (INIS)

Lyou, Chae Yeon; Kim, Sun Mi; Jang, Mi Jung; Kim, Sung Won; Kang, Eun Young; Park, So Yeon; Moon, Woo Kyung

2011-01-01

We wanted to evaluate the interobserver variability and diagnostic performance of 3-dimensional (3D) breast ultrasound (US) as compared with that of 2- dimensional (2D) US. We included 150 patients who received US-guided core biopsy and 3D US between June 2009 and April 2010. Three breast imaging radiologists analyzed the 2D and 3D US images using the Breast Imaging Reporting and Data System (BI-RADS) lexicon. The intra-observer agreement and inter-observer agreement were calculated. The sensitivity and specificity of 2D and 3D US were evaluated. The intra-observer agreement between 2D and 3D US was mostly slight or fair agreement. However, in terms of the final category, there was substantial agreement for all three radiologists. The inter-observer agreement of 3D US was similar to that of 2D US (moderate agreement for shape, orientation, circumscribed margin and boundary: fair agreement for indistinct margin, angular margin, microlobulated margin, echo pattern and final category). The sensitivity of 3D US for breast cancer was higher than that of 2D US for two radiologists (2D vs. 3D for reader 2: 55.8% vs. 61.5%, 2D vs. 3D for reader 3: 59.6% vs. 63.5%), and the specificity of 3D US was lower than that of 2D US for all the readers (2D vs. 3D for reader 1: 90.8% vs. 86.7%, 2D vs. 3D for reader 2: 90.8% vs. 87.8%, 2D vs. 3D for reader 3: 94.9% vs. 90.8%), but the difference was not significant (p ≥ 0.05). The interobserver variability and diagnostic performance of 3D breast US were similar to those of 2D US

Automated 3D ultrasound measurement of the angle of progression in labor.

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Montaguti, Elisa; Rizzo, Nicola; Pilu, Gianluigi; Youssef, Aly

2018-01-01

To assess the feasibility and reliability of an automated technique for the assessment of the angle of progression (AoP) in labor by using three-dimensional (3D) ultrasound. AoP was assessed by using 3D transperineal ultrasound by two operators in 52 women in active labor to evaluate intra- and interobserver reproducibility. Furthermore, intermethod agreement between automated and manual techniques on 3D images, and between automated technique on 3D vs 2D images were evaluated. Automated measurements were feasible in all cases. Automated measurements were considered acceptable in 141 (90.4%) out of the 156 on the first assessments and in all 156 after repeating measurements for unacceptable evaluations. The automated technique on 3D images demonstrated good intra- and interobserver reproducibility. The 3D-automated technique showed a very good agreement with the 3D manual technique. Notably, AoP calculated with the 3D automated technique were significantly wider in comparison with those measured manually on 3D images (133 ± 17° vs 118 ± 21°, p = 0.013). The assessment of the angle of progression through 3D ultrasound is highly reproducible. However, automated software leads to a systematic overestimation of AoP in comparison with the standard manual technique thus hindering its use in clinical practice in its present form.

Status for the two-dimensional Navier-Stokes solver EllipSys2D

Energy Technology Data Exchange (ETDEWEB)

Bertagnolio, F.; Soerensen, N.; Johansen, J.

2001-08-01

This report sets up an evaluation of two-dimensional Navier-Stokes solver EllipSys2D in its present state. This code is used for blade aerodynamics simulations in the Aeroelastic Design group at Risoe. Two airfoils are investigated by computing the flow at several angles of attack ranging from the linear to the stalled region. The computational data are compared to experimental data and numerical results from other computational codes. Several numerical aspects are studied, as mesh dependency, convective scheme, steady state versus unsteady computations, transition modelling. Some general conclusions intended to help in using this code for numerical simulations are given. (au)

Induction of Chirality in Two-Dimensional Nanomaterials: Chiral 2D MoS2 Nanostructures.

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Purcell-Milton, Finn; McKenna, Robert; Brennan, Lorcan J; Cullen, Conor P; Guillemeney, Lilian; Tepliakov, Nikita V; Baimuratov, Anvar S; Rukhlenko, Ivan D; Perova, Tatiana S; Duesberg, Georg S; Baranov, Alexander V; Fedorov, Anatoly V; Gun'ko, Yurii K

2018-02-27

Two-dimensional (2D) nanomaterials have been intensively investigated due to their interesting properties and range of potential applications. Although most research has focused on graphene, atomic layered transition metal dichalcogenides (TMDs) and particularly MoS 2 have gathered much deserved attention recently. Here, we report the induction of chirality into 2D chiral nanomaterials by carrying out liquid exfoliation of MoS 2 in the presence of chiral ligands (cysteine and penicillamine) in water. This processing resulted in exfoliated chiral 2D MoS 2 nanosheets showing strong circular dichroism signals, which were far past the onset of the original chiral ligand signals. Using theoretical modeling, we demonstrated that the chiral nature of MoS 2 nanosheets is related to the presence of chiral ligands causing preferential folding of the MoS 2 sheets. There was an excellent match between the theoretically calculated and experimental spectra. We believe that, due to their high aspect ratio planar morphology, chiral 2D nanomaterials could offer great opportunities for the development of chiroptical sensors, materials, and devices for valleytronics and other potential applications. In addition, chirality plays a key role in many chemical and biological systems, with chiral molecules and materials critical for the further development of biopharmaceuticals and fine chemicals, and this research therefore should have a strong impact on relevant areas of science and technology such as nanobiotechnology, nanomedicine, and nanotoxicology.

Five-dimensional ultrasound system for soft tissue visualization.

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Deshmukh, Nishikant P; Caban, Jesus J; Taylor, Russell H; Hager, Gregory D; Boctor, Emad M

2015-12-01

A five-dimensional ultrasound (US) system is proposed as a real-time pipeline involving fusion of 3D B-mode data with the 3D ultrasound elastography (USE) data as well as visualization of these fused data and a real-time update capability over time for each consecutive scan. 3D B-mode data assist in visualizing the anatomy of the target organ, and 3D elastography data adds strain information. We investigate the feasibility of such a system and show that an end-to-end real-time system, from acquisition to visualization, can be developed. We present a system that consists of (a) a real-time 3D elastography algorithm based on a normalized cross-correlation (NCC) computation on a GPU; (b) real-time 3D B-mode acquisition and network transfer; (c) scan conversion of 3D elastography and B-mode volumes (if acquired by 4D wobbler probe); and (d) visualization software that fuses, visualizes, and updates 3D B-mode and 3D elastography data in real time. We achieved a speed improvement of 4.45-fold for the threaded version of the NCC-based 3D USE versus the non-threaded version. The maximum speed was 79 volumes/s for 3D scan conversion. In a phantom, we validated the dimensions of a 2.2-cm-diameter sphere scan-converted to B-mode volume. Also, we validated the 5D US system visualization transfer function and detected 1- and 2-cm spherical objects (phantom lesion). Finally, we applied the system to a phantom consisting of three lesions to delineate the lesions from the surrounding background regions of the phantom. A 5D US system is achievable with real-time performance. We can distinguish between hard and soft areas in a phantom using the transfer functions.

Two-dimensional multifractal cross-correlation analysis

International Nuclear Information System (INIS)

Xi, Caiping; Zhang, Shuning; Xiong, Gang; Zhao, Huichang; Yang, Yonghong

2017-01-01

Highlights: • We study the mathematical models of 2D-MFXPF, 2D-MFXDFA and 2D-MFXDMA. • Present the definition of the two-dimensional N 2 -partitioned multiplicative cascading process. • Do the comparative analysis of 2D-MC by 2D-MFXPF, 2D-MFXDFA and 2D-MFXDMA. • Provide a reference on the choice and parameter settings of these methods in practice. - Abstract: There are a number of situations in which several signals are simultaneously recorded in complex systems, which exhibit long-term power-law cross-correlations. This paper presents two-dimensional multifractal cross-correlation analysis based on the partition function (2D-MFXPF), two-dimensional multifractal cross-correlation analysis based on the detrended fluctuation analysis (2D-MFXDFA) and two-dimensional multifractal cross-correlation analysis based on the detrended moving average analysis (2D-MFXDMA). We apply these methods to pairs of two-dimensional multiplicative cascades (2D-MC) to do a comparative study. Then, we apply the two-dimensional multifractal cross-correlation analysis based on the detrended fluctuation analysis (2D-MFXDFA) to real images and unveil intriguing multifractality in the cross correlations of the material structures. At last, we give the main conclusions and provide a valuable reference on how to choose the multifractal algorithms in the potential applications in the field of SAR image classification and detection.

Real-time 3-dimensional contrast-enhanced ultrasound in detecting hemorrhage of blunt renal trauma.

Science.gov (United States)

Xu, Rui-Xue; Li, Ye-Kuo; Li, Ting; Wang, Sha-Sha; Yuan, Gui-Zhong; Zhou, Qun-Fang; Zheng, Hai-Rong; Yan, Fei

2013-10-01

The objective of this study is to evaluate the diagnostic value of real-time 3-dimensional contrast-enhanced ultrasound in the hemorrhage of blunt renal trauma. Eighteen healthy New Zealand white rabbits were randomly divided into 3 groups. Blunt renal trauma was performed on each group by using minitype striker. Ultrasonography, color Doppler flow imaging, and contrast-enhanced 2-dimensional and real-time 3-dimensional ultrasound were applied before and after the strike. The time to shock and blood pressure were subjected to statistical analysis. Then, a comparative study of ultrasound and pathology was carried out. All the struck kidneys were traumatic. In the ultrasonography, free fluid was found under the renal capsule. In the color Doppler flow imaging, active hemorrhage was not identified. In 2-dimensional contrast-enhanced ultrasound, active hemorrhage of the damaged kidney was characterized. Real-time 3-dimensional contrast-enhanced ultrasound showed a real-time and stereoscopic ongoing bleeding of the injured kidney. The wider the hemorrhage area in 4-dimensional contrast-enhanced ultrasound was, the faster the blood pressure decreased. Real-time 3-dimensional contrast-enhanced ultrasound is a promising noninvasive tool for stereoscopically and vividly detecting ongoing hemorrhage of blunt renal trauma in real time. © 2013.

Advantages and disadvantages of 3D ultrasound of thyroid nodules including thin slice volume rendering

Directory of Open Access Journals (Sweden)

Slapa Rafal

2011-01-01

Full Text Available Abstract Background The purpose of this study was to assess the advantages and disadvantages of 3D gray-scale and power Doppler ultrasound, including thin slice volume rendering (TSVR, applied for evaluation of thyroid nodules. Methods The retrospective evaluation by two observers of volumes of 71 thyroid nodules (55 benign, 16 cancers was performed using a new TSVR technique. Dedicated 4D ultrasound scanner with an automatic 6-12 MHz 4D probe was used. Statistical analysis was performed with Stata v. 8.2. Results Multiple logistic regression analysis demonstrated that independent risk factors of thyroid cancers identified by 3D ultrasound include: (a ill-defined borders of the nodule on MPR presentation, (b a lobulated shape of the nodule in the c-plane and (c a density of central vessels in the nodule within the minimal or maximal ranges. Combination of features provided sensitivity 100% and specificity 60-69% for thyroid cancer. Calcification/microcalcification-like echogenic foci on 3D ultrasound proved not to be a risk factor of thyroid cancer. Storage of the 3D data of the whole nodules enabled subsequent evaluation of new parameters and with new rendering algorithms. Conclusions Our results indicate that 3D ultrasound is a practical and reproducible method for the evaluation of thyroid nodules. 3D ultrasound stores volumes comprising the whole lesion or organ. Future detailed evaluations of the data are possible, looking for features that were not fully appreciated at the time of collection or applying new algorithms for volume rendering in order to gain important information. Three-dimensional ultrasound data could be included in thyroid cancer databases. Further multicenter large scale studies are warranted.

Effects on the Thermo-Mechanical and Crystallinity Properties of Nylon 6,6 Electrospun Fibres Reinforced with One Dimensional (1D and Two Dimensional (2D Carbon

Directory of Open Access Journals (Sweden)

Francisco Medellín-Rodríguez

2013-08-01

Full Text Available Electrospun one dimensional (1D and two dimensional (2D carbon based polymer nanocomposites are studied in order to determine the effect provided by the two differently structured nanofillers on crystallinity and thermo-mechanical properties of the nanofibres. The nanomaterials studied are pristine carbon nanotubes, oxidised carbon nanotubes, reduced graphene oxide and graphene oxide. Functional groups associated with the order structure of the polymers are analysed by infrared and Raman spectroscopies; the morphology is studied by scanning electron microscopy and the crystallinity properties are investigated by differential scanning calorimetry and X-ray diffraction. Differences in crystallisation behaviour between 1D and 2D carbon based nanofibres are shown by their crystallinity degree and their crystal sizes. The nanocomposite crystal sizes perpendicular to the plane (100 decrease with nanofiller content in all cases. The crystallinity trend and crystal sizes are in accordance with storage modulus response. The results also suggest that functionalisation favours interfacial bonding and dispersion of the nanomaterials within the polymer matrix. As a consequence the number of nucleating sites increases which in turn decreases the crystal size in the nanocomposites. These features explain the improved thermo-mechanical properties in the nanocomposites.

Prognostic value of three-dimensional ultrasound for fetal hydronephrosis

Science.gov (United States)

WANG, JUNMEI; YING, WEIWEN; TANG, DAXING; YANG, LIMING; LIU, DONGSHENG; LIU, YUANHUI; PAN, JIAOE; XIE, XING

2015-01-01

The present study evaluated the prognostic value of three-dimensional ultrasound for fetal hydronephrosis. Pregnant females with fetal hydronephrosis were enrolled and a novel three-dimensional ultrasound indicator, renal parenchymal volume/kidney volume, was introduced to predict the postnatal prognosis of fetal hydronephrosis in comparison with commonly used ultrasound indicators. All ultrasound indicators of fetal hydronephrosis could predict whether postnatal surgery was required for fetal hydronephrosis; however, the predictive performance of renal parenchymal volume/kidney volume measurements as an individual indicator was the highest. In conclusion, ultrasound is important in predicting whether postnatal surgery is required for fetal hydronephrosis, and the three-dimensional ultrasound indicator renal parenchymal volume/kidney volume has a high predictive performance. Furthermore, the majority of cases of fetal hydronephrosis spontaneously regress subsequent to birth, and the regression time is closely associated with ultrasound indicators. PMID:25667626

Power Doppler flow mapping and four-dimensional ultrasound for evaluating tubal patency compared with laparoscopy.

Science.gov (United States)

Soliman, Amr A; Shaalan, Waleed; Abdel-Dayem, Tamer; Awad, Elsayed Elbadawy; Elkassar, Yasser; Lüdders, Dörte; Malik, Eduard; Sallam, Hassan N

2015-12-01

To study the accuracy of four-dimensional (4D) ultrasound and power Doppler flow mapping in detecting tubal patency in women with sub-/infertility, and compare it with laparoscopy and chromopertubation. A prospective study. The study was performed in the outpatient clinic and infertility unit of a university hospital. The sonographic team and laparoscopic team were blinded to the results of each other. Women aged younger than 43 years seeking medical advice due to primary or secondary infertility and who planned to have a diagnostic laparoscopy performed, were recruited to the study after signing an informed consent. All of the recruited patients had power Doppler flow mapping and 4D hysterosalpingo-sonography by injecting sterile saline into the fallopian tubes 1 day before surgery. Registering Doppler signals, while using power Doppler, both at the tubal ostia and fimbrial end and the ability to demonstrate the course of the tube especially the isthmus and fimbrial end, while using 4D mode, was considered a patent tube. Out of 50 recruited patients, 33 women had bilateral patent tubes and five had unilateral patent tubes as shown by chromopertubation during diagnostic laparoscopy. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for two-dimensional power Doppler hysterosalpingography were 94.4%, 100%, 100%, 89.2%, and 96.2%, respectively and for 4D ultrasound were 70.4%, 100%, 100%, 70.4%, and 82.6%, respectively. Four-dimensional saline hysterosalpingography has acceptable accuracy in detecting tubal patency, but is surpassed by power Doppler saline hysterosalpingography. Power Doppler saline hysterosalpingography could be incorporated into the routine sub-/infertility workup. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Picture perfect: benefits and risk of fetal 3D ultrasound.

Science.gov (United States)

Wiseman, Claudia S; Kiehl, Ermalynn M

2007-01-01

The purpose of this literature review was to survey available information and research related to routine three-dimensional (3D) ultrasound technology in obstetrics, with an emphasis on current medical uses, safety, and availability issues. Several data bases, including Cochrane, WHO, NIH, CINALH, Blackwell Synergy, ERIC, PubMed, and Medline, were used along with information from Internet search engines. Although fetal 3D ultrasound is used in both medical and commercial settings, recent studies focus on its possible uses rather than the more difficult issues of safety and commercial applications. Professional organizations associated with ultrasound technology support limiting ultrasounds in pregnancy to medically necessary events, whereas commercial venues use "direct to consumer" marketing to promote this technology as a way to "see" the baby before it is born. How safe is routine or frequent use of 3D ultrasound? Further research is needed to address these important questions.

Learning process for performing and analyzing 3D/4D transperineal ultrasound imaging and interobserver reliability study.

Science.gov (United States)

Siafarikas, F; Staer-Jensen, J; Braekken, I H; Bø, K; Engh, M Ellström

2013-03-01

To evaluate the learning process for acquiring three- and four-dimensional (3D/4D) transperineal ultrasound volumes of the levator hiatus (LH) dimensions at rest, during pelvic floor muscle (PFM) contraction and on Valsalva maneuver, and for analyzing the ultrasound volumes, as well as to perform an interobserver reliability study between two independent ultrasound examiners. This was a prospective study including 22 women. We monitored the learning process of an inexperienced examiner (IE) performing 3D/4D transperineal ultrasonography and analyzing the volumes. The examination included acquiring volumes during three PFM contractions and three Valsalva maneuvers. LH dimensions were determined in the axial plane. The learning process was documented by estimating agreement between the IE and an experienced examiner (E) using the intraclass correlation coefficient. Agreement was calculated in blocks of 10 ultrasound examinations and analyzed volumes. After the learning process was complete the interobserver reliability for the technique was calculated between these two independent examiners. For offline analysis of the first 10 ultrasound volumes obtained by E, good to very good agreement between E and IE was achieved for all LH measurements except for the left and right levator-urethra gap and pubic arc. For the next 10 analyzed volumes, agreement improved for all LH measurements. Volumes that had been obtained by IE and E were then re-evaluated by IE, and good to very good agreement was found for all LH measurements indicating consistency in volume acquisition. The interobserver reliability study showed excellent ICC values (ICC, 0.81-0.97) for all LH measurements except the pubic arc (ICC = 0.67). 3D/4D transperineal ultrasound is a reliable technique that can be learned in a short period of time. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Two-dimensional fluorescence lifetime correlation spectroscopy. 2. Application.

Science.gov (United States)

Ishii, Kunihiko; Tahara, Tahei

2013-10-03

In the preceding article, we introduced the theoretical framework of two-dimensional fluorescence lifetime correlation spectroscopy (2D FLCS). In this article, we report the experimental implementation of 2D FLCS. In this method, two-dimensional emission-delay correlation maps are constructed from the photon data obtained with the time-correlated single photon counting (TCSPC), and then they are converted to 2D lifetime correlation maps by the inverse Laplace transform. We develop a numerical method to realize reliable transformation, employing the maximum entropy method (MEM). We apply the developed actual 2D FLCS to two real systems, a dye mixture and a DNA hairpin. For the dye mixture, we show that 2D FLCS is experimentally feasible and that it can identify different species in an inhomogeneous sample without any prior knowledge. The application to the DNA hairpin demonstrates that 2D FLCS can disclose microsecond spontaneous dynamics of biological molecules in a visually comprehensible manner, through identifying species as unique lifetime distributions. A FRET pair is attached to the both ends of the DNA hairpin, and the different structures of the DNA hairpin are distinguished as different fluorescence lifetimes in 2D FLCS. By constructing the 2D correlation maps of the fluorescence lifetime of the FRET donor, the equilibrium dynamics between the open and the closed forms of the DNA hairpin is clearly observed as the appearance of the cross peaks between the corresponding fluorescence lifetimes. This equilibrium dynamics of the DNA hairpin is clearly separated from the acceptor-missing DNA that appears as an isolated diagonal peak in the 2D maps. The present study clearly shows that newly developed 2D FLCS can disclose spontaneous structural dynamics of biological molecules with microsecond time resolution.

Two Dimensional X-Ray Diffraction (2D-XRD) studies on Olivine of U.S.A

International Nuclear Information System (INIS)

Jabeen, S.; Raza, S.M.; Ahmed, M.A.; Zai, M.Y.; Elacher, K.

2011-01-01

The Olivine (Mg, Fe) 2SiO/sub 4/ of USA has been studied with two dimensional X-ray diffractometer (D8 discover with GADDS). The two distinct phases of orthorhombic structure, one with Mg/sub 8/[Fe/sub 2/SiO/sub 4/] and the other with Mg/sub 2/SiO/sub 4/ is observed. We also observed phase transitions due to presence of iron and Silicon preferably the structural change of Mg/sub 8/[Fe/sub 2/SiO/sub 4/] from orthorhombic to spinel like (spinel chord) structure. Magnesium ions in Mg/sub 8/[Fe/sub 2/SiO/sub 4/] shuffle, arrange at the five vertices of a pentagon and the remaining three at the central but with displaced position from the plane of the pentagon, Thus resulting into a three dimensional spinel chord like structure. We evidenced the same from diverse orientations of phase peaks and indeed from Kossel lines. (author)

Prenatal diagnosis of bilateral anophthalmia by 3D "reverse face" view ultrasound and magnetic resonance imaging.

Science.gov (United States)

Araujo Júnior, Edward; Kawanami, Tatiana Emy; Nardozza, Luciano Marcondes Machado; Milani, Hérbene José Figuinha; Oliveira, Patrícia Soares; Moron, Antonio Fernandes

2012-12-01

Primary anophthalmia is a rare congenital malformation that affects 0.6/10,000 liveborn infants. It is usually associated with central nervous system malformations, aneuploidies, cytomegalovirus infection and mental retardation and it can also be part of genetic conditions such as Fraser, Goltz, Goldenhar, Waardenburg and Lenz syndromes. Neonatal prognosis depends on whether anophthalmia is an isolated malformation, or it is associated with other defects or part of a syndrome. A healthy 43-year-old woman, G4 P3 with three previous healthy children, was referred to our clinic for a routine obstetric ultrasound at 28 weeks' gestation. The fetal eye globes and lenses could not be seen on two-dimensional (2D) ultrasound, which led to the diagnosis of bilateral congenital anophthalmia. No other fetal malformations were detected. At 30 weeks' gestation, a three-dimensional (3D) ultrasound was performed using the rendering mode and "reverse face" view. Using this technique, the absence of both eye globes could be clearly seen through a "slit". 3D-ultrasound allowed the parents to better understand their child's problem and possible postnatal implications. Fetal magnetic resonance imaging (MRI) was also performed, to study the fetal cortex in more detail. This exam revealed right cerebral hemisphere sulci and gyri hypoplasia. At 41 1/7 weeks, she went into spontaneous labor and delivered vaginally a 3525 g male infant with Apgar scores of 9 and 10. Postnatal exams confirmed bilateral congenital anophthalmia. This is the first case report in the literature of prenatal diagnosis of bilateral anophthalmia using 3D "reverse face" view ultrasound and MRI. Copyright © 2012. Published by Elsevier B.V.

Fetal cardiac stroke volume determination by four-dimensional ultrasound with spatio-temporal image correlation compared with two-dimensional and Doppler ultrasonography.

Science.gov (United States)

Rizzo, Giuseppe; Capponi, Alessandra; Cavicchioni, Ottavia; Vendola, Marianne; Arduini, Domenico

2007-12-01

To assess the agreement of stroke volume (SV) measured with two-dimensional (2D) ultrasonography with Doppler capability (vs) four-dimensional (4D) with spatiotemporal image correlation (STIC) in normal and growth restricted fetuses. 2D Doppler and 4D STIC were used to measure SV of 40 normal fetuses at 20 to 22 and 28 to 32 weeks, and 16 growth-restricted fetuses at 26 to 34 weeks of gestation. Intraclass correlation was used to evaluate the agreement between left and right SV obtained by the two techniques, and proportionate Bland-Altman plots constructed. The time necessary to obtain SV was analyzed. The intraclass correlation coefficient between 2D Doppler and 4D STIC measurements for the left ventricle were 0.977 and 0.980 for the right ventricle. The proportionate limits of agreement between the two methods were 18.7 to 23.9% for the left ventricle and - 20.9 to 21.7% for the right ventricle. The time necessary to measure SV was significantly shorter with 4D STIC (3.1 (vs) 7.9 min p < 0.0001) than with 2D Doppler. There is a good agreement between SV measured either by 2D Doppler or by 4D STIC. The 4D STIC represents a simple and rapid technique to estimate fetal SV and promises to become the method of choice. Copyright (c) 2007 John Wiley & Sons, Ltd.

A 3D Polymer Based Printed Two-Dimensional Laser Scanner

International Nuclear Information System (INIS)

Oyman, H A; Yalcinkaya, A D; Gokdel, Y D; Ferhanoglu, O

2016-01-01

A two-dimensional (2D) polymer based scanning mirror with magnetic actuation is developed for imaging applications. Proposed device consists of a circular suspension holding a rectangular mirror and can generate a 2D scan pattern. Three dimensional (3D) printing technology which is used for implementation of the device, offers added flexibility in controlling the cross-sectional profile as well as the stress distribution compared to the traditional planar process technologies. The mirror device is developed to meet a portable, miniaturized confocal microscope application in mind, delivering 4.5 and 4.8 degrees of optical scan angles at 111 and 267 Hz, respectively. As a result of this mechanical performance, the resulting microscope incorporating the mirror is estimated to accomplish a field of view (FOV) of 350 µm × 350 µm. (paper)

Screened Raman response in two-dimensional d(x2-y2)-wave superconductors: Relative intensities in different symmetry channels

DEFF Research Database (Denmark)

Wenger, F.; Käll, M.

1997-01-01

We analyze the Raman-scattering response in a two-dimensional d(x2-y2)-wave superconductor and point out a strong suppression of relative intensity in the screened A(1g) channel compared to the B-1g channel for a generic tight-binding model. This is in contrast with the observed behavior in high...

FireStem2D — A two-dimensional heat transfer model for simulating tree stem injury in fires

Science.gov (United States)

Efthalia K. Chatziefstratiou; Gil Bohrer; Anthony S. Bova; Ravishankar Subramanian; Renato P.M. Frasson; Amy Scherzer; Bret W. Butler; Matthew B. Dickinson

2013-01-01

FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem) and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by...

Three- and four-dimensional ultrasound in fetal echocardiography: an up-to-date overview

NARCIS (Netherlands)

Adriaanse, B.M.; Vugt, J.M.G. van; Haak, M.C.

2016-01-01

Congenital heart diseases (CHD) are the most commonly overlooked lesions in prenatal screening programs. Real-time two-dimensional ultrasound (2DUS) is the conventionally used tool for fetal echocardiography. Although continuous improvements in the hardware and post-processing software have resulted

An integrated circuit with transmit beamforming flip-chip bonded to a 2-D CMUT array for 3-D ultrasound imaging.

Science.gov (United States)

Wygant, Ira O; Jamal, Nafis S; Lee, Hyunjoo J; Nikoozadeh, Amin; Oralkan, Omer; Karaman, Mustafa; Khuri-Yakub, Butrus T

2009-10-01

State-of-the-art 3-D medical ultrasound imaging requires transmitting and receiving ultrasound using a 2-D array of ultrasound transducers with hundreds or thousands of elements. A tight combination of the transducer array with integrated circuitry eliminates bulky cables connecting the elements of the transducer array to a separate system of electronics. Furthermore, preamplifiers located close to the array can lead to improved receive sensitivity. A combined IC and transducer array can lead to a portable, high-performance, and inexpensive 3-D ultrasound imaging system. This paper presents an IC flip-chip bonded to a 16 x 16-element capacitive micromachined ultrasonic transducer (CMUT) array for 3-D ultrasound imaging. The IC includes a transmit beamformer that generates 25-V unipolar pulses with programmable focusing delays to 224 of the 256 transducer elements. One-shot circuits allow adjustment of the pulse widths for different ultrasound transducer center frequencies. For receiving reflected ultrasound signals, the IC uses the 32-elements along the array diagonals. The IC provides each receiving element with a low-noise 25-MHz-bandwidth transimpedance amplifier. Using a field-programmable gate array (FPGA) clocked at 100 MHz to operate the IC, the IC generated properly timed transmit pulses with 5-ns accuracy. With the IC flip-chip bonded to a CMUT array, we show that the IC can produce steered and focused ultrasound beams. We present 2-D and 3-D images of a wire phantom and 2-D orthogonal cross-sectional images (Bscans) of a latex heart phantom.

Two-dimensional numerical experiments with DRIX-2D on two-phase-water-flows referring to the HDR-blowdown-experiments

International Nuclear Information System (INIS)

Moesinger, H.

1979-08-01

The computer program DRIX-2D has been developed from SOLA-DF. The essential elements of the program structure are described. In order to verify DRIX-2D an Edwards-Blowdown-Experiment is calculated and other numerical results are compared with steady state experiments and models. Numerical experiments on transient two-phase flow, occurring in the broken pipe of a PWR in the case of a hypothetic LOCA, are performed. The essential results of the two-dimensional calculations are: 1. The appearance of a radial profile of void-fraction, velocity, sound speed and mass flow-rate inside the blowdown nozzle. The reason for this is the flow contraction at the nozzle inlet leading to more vapour production in the vicinity of the pipe wall. 2. A comparison between modelling in axisymmetric and Cartesian coordinates and calculations with and without the core barrel show the following: a) The three-dimensional flow pattern at the nozzle inlet is poorly described using Cartesian coordinates. In consequence a considerable difference in pressure history results. b) The core barrel alters the reflection behaviour of the pressure waves oscillating in the blowdown-nozzle. Therefore, the core barrel should be modelled as a wall normal to the nozzle axis. (orig./HP) [de

MARG2D code. 1. Eigenvalue problem for two dimensional Newcomb equation

Energy Technology Data Exchange (ETDEWEB)

Tokuda, Shinji [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Watanabe, Tomoko

1997-10-01

A new method and a code MARG2D have been developed to solve the 2-dimensional Newcomb equation which plays an important role in the magnetohydrodynamic (MHD) stability analysis in an axisymmetric toroidal plasma such as a tokamak. In the present formulation, an eigenvalue problem is posed for the 2-D Newcomb equation, where the weight function (the kinetic energy integral) and the boundary conditions at rational surfaces are chosen so that an eigenfunction correctly behaves as the linear combination of the small solution and the analytical solutions around each of the rational surfaces. Thus, the difficulty on solving the 2-D Newcomb equation has been resolved. By using the MARG2D code, the ideal MHD marginally stable state can be identified for a 2-D toroidal plasma. The code is indispensable on computing the outer-region matching data necessary for the resistive MHD stability analysis. Benchmark with ERATOJ, an ideal MHD stability code, has been carried out and the MARG2D code demonstrates that it indeed identifies both stable and marginally stable states against ideal MHD motion. (author)

Development of 2-D/1-D fusion method for three-dimensional whole-core heterogeneous neutron transport calculations

International Nuclear Information System (INIS)

Lee, Gil Soo

2006-02-01

To describe power distribution and multiplication factor of a reactor core accurately, it is necessary to perform calculations based on neutron transport equation considering heterogeneous geometry and scattering angles. These calculations require very heavy calculations and were nearly impossible with computers of old days. From the limitation of computing power, traditional approach of reactor core design consists of heterogeneous transport calculation in fuel assembly level and whole core diffusion nodal calculation with assembly homogenized properties, resulting from fuel assembly transport calculation. This approach may be effective in computation time, but it gives less accurate results for highly heterogeneous problems. As potential for whole core heterogeneous transport calculation became more feasible owing to rapid development of computing power during last several years, the interests in two and three dimensional whole core heterogeneous transport calculations by deterministic method are increased. For two dimensional calculation, there were several successful approaches using even parity transport equation with triangular meshes, S N method with refined rectangular meshes, the method of characteristics (MOC) with unstructured meshes, and so on. The work in this thesis originally started from the two dimensional whole core heterogeneous transport calculation by using MOC. After successful achievement in two dimensional calculation, there were efforts in three-dimensional whole-core heterogeneous transport calculation using MOC. Since direct extension to three dimensional calculation of MOC requires too much computing power, indirect approach to three dimensional calculation was considered.Thus, 2D/1D fusion method for three dimensional heterogeneous transport calculation was developed and successfully implemented in a computer code. The 2D/1D fusion method is synergistic combination of the MOC for radial 2-D calculation and S N -like methods for axial 1

Neuronavigation for arteriovenous malformation surgery by intraoperative three-dimensional ultrasound angiography.

Science.gov (United States)

Mathiesen, Tiit; Peredo, Inti; Edner, Göran; Kihlström, Lars; Svensson, Mikael; Ulfarsson, Elfar; Andersson, Tommy

2007-04-01

Neuronavigational devices have traditionally used preoperative imaging with limited possibilities for adjustment to brain shift and intraoperative manipulation of the surgical lesions. We have used an intraoperative imaging and navigation system that uses navigation on intraoperatively acquired three-dimensional ultrasound data, as well as preoperatively acquired magnetic resonance imaging scans and magnetic resonance angiograms. The usefulness of this system for arteriovenous malformation (AVM) surgery was evaluated prospectively. Nine consecutive patients with Spetzler Grade 1 (n = 3), 2 (n = 3), 3(n = 2) or 4 (n = 1) AVMs underwent operation using this intraoperative imaging and navigation system. The system provides real-time rendering of three-dimensional angiographic data and can visualize such projections in a stereoscopic (virtual reality) manner using special glasses. The experiences with this technology were analyzed and the outcomes assessed. Angiographic reconstructions of three-dimensional images were obtained before and after resection. Conventional navigation on the basis of preoperative magnetic resonance angiography was helpful to secure positioning of the bone flap; stereoscopic visualization of the same data represented a powerful means to construct a mental three-dimensional picture of the extent of the AVM and the feeder anatomy even before skin incision. Intraoperative ultrasound corresponded well to the intraoperative findings and allowed confirmation of feeding vessels in surrounding gyri and rapid identification of the perinidal dissection planes, regardless of brain shift. The latter feature was particularly helpful because the intraoperative navigational identification of surgical planes leads to minimal exploration into the nidus or dissection at a greater distance from the malformation. Application of the system was thought to increase surgical confidence. In two patients, postresection ultrasound prompted additional nidus removal

Advanced 3-D Ultrasound Imaging: 3-D Synthetic Aperture Imaging using Fully Addressed and Row-Column Addressed 2-D Transducer Arrays

DEFF Research Database (Denmark)

Bouzari, Hamed

the important diagnostic information in a noninvasive manner. Diagnostic and therapeutic decisions often require accurate estimates of e.g., organ, cyst, or tumor volumes. 3-D ultrasound imaging can provide these measurements without relying on the geometrical assumptions and operator-dependent skills involved...... is one of the factors for the widespread use of ultrasound imaging. The high price tag on the high quality 3-D scanners is limiting their market share. Row-column addressing of 2-D transducer arrays is a low cost alternative to fully addressed 2-D arrays, for 3-D ultrasound imaging. Using row....... Based on a set of acoustical measurements the center frequency, bandwidth, surface pressure, sensitivity, and acoustical cross-talks were evaluated and discussed. The imaging quality assessments were carried out based on Field II simulations as well as phantom measurements. Moreover, an analysis...

2D sparse array transducer optimization for 3D ultrasound imaging

International Nuclear Information System (INIS)

Choi, Jae Hoon; Park, Kwan Kyu

2014-01-01

A 3D ultrasound image is desired in many medical examinations. However, the implementation of a 2D array, which is needed for a 3D image, is challenging with respect to fabrication, interconnection and cabling. A 2D sparse array, which needs fewer elements than a dense array, is a realistic way to achieve 3D images. Because the number of ways the elements can be placed in an array is extremely large, a method for optimizing the array configuration is needed. Previous research placed the target point far from the transducer array, making it impossible to optimize the array in the operating range. In our study, we focused on optimizing a 2D sparse array transducer for 3D imaging by using a simulated annealing method. We compared the far-field optimization method with the near-field optimization method by analyzing a point-spread function (PSF). The resolution of the optimized sparse array is comparable to that of the dense array.

Actuator-Assisted Calibration of Freehand 3D Ultrasound System.

Science.gov (United States)

Koo, Terry K; Silvia, Nathaniel

2018-01-01

Freehand three-dimensional (3D) ultrasound has been used independently of other technologies to analyze complex geometries or registered with other imaging modalities to aid surgical and radiotherapy planning. A fundamental requirement for all freehand 3D ultrasound systems is probe calibration. The purpose of this study was to develop an actuator-assisted approach to facilitate freehand 3D ultrasound calibration using point-based phantoms. We modified the mathematical formulation of the calibration problem to eliminate the need of imaging the point targets at different viewing angles and developed an actuator-assisted approach/setup to facilitate quick and consistent collection of point targets spanning the entire image field of view. The actuator-assisted approach was applied to a commonly used cross wire phantom as well as two custom-made point-based phantoms (original and modified), each containing 7 collinear point targets, and compared the results with the traditional freehand cross wire phantom calibration in terms of calibration reproducibility, point reconstruction precision, point reconstruction accuracy, distance reconstruction accuracy, and data acquisition time. Results demonstrated that the actuator-assisted single cross wire phantom calibration significantly improved the calibration reproducibility and offered similar point reconstruction precision, point reconstruction accuracy, distance reconstruction accuracy, and data acquisition time with respect to the freehand cross wire phantom calibration. On the other hand, the actuator-assisted modified "collinear point target" phantom calibration offered similar precision and accuracy when compared to the freehand cross wire phantom calibration, but it reduced the data acquisition time by 57%. It appears that both actuator-assisted cross wire phantom and modified collinear point target phantom calibration approaches are viable options for freehand 3D ultrasound calibration.

The role of three-dimensional ultrasound in the differential diagnosis of

Directory of Open Access Journals (Sweden)

Mustafa Ersöz

2011-03-01

Full Text Available Gastroschisis and omphalocele are the two of the mostcommon malformations of the anterior abdominal wallthat both of them associated with high morbidity andmortality. Sometimes the diagnosis and the realization ofthe situations by physicians and the parents are difficult.Herein, one omphalocele and one gastroschisis caseswere presented with the two-dimensional and threedimensionalultrasonographic diagnostic features. Thetwo entities and the role of three-dimensionalultrasound in diagnosis and the clinical management ofthe situations are discussed in the view of medicalliterature. The three-dimensional ultrasound helps in thediagnosis and detection of the severity of theomphalocele and the gastroschisis. J Clin Exp Invest2011; 2(1: 106-109

(d -2 ) -Dimensional Edge States of Rotation Symmetry Protected Topological States

Science.gov (United States)

Song, Zhida; Fang, Zhong; Fang, Chen

2017-12-01

We study fourfold rotation-invariant gapped topological systems with time-reversal symmetry in two and three dimensions (d =2 , 3). We show that in both cases nontrivial topology is manifested by the presence of the (d -2 )-dimensional edge states, existing at a point in 2D or along a line in 3D. For fermion systems without interaction, the bulk topological invariants are given in terms of the Wannier centers of filled bands and can be readily calculated using a Fu-Kane-like formula when inversion symmetry is also present. The theory is extended to strongly interacting systems through the explicit construction of microscopic models having robust (d -2 )-dimensional edge states.

Two-dimensional grayscale ultrasound and spectral Doppler waveform evaluation of dogs with chronic enteropathies.

Science.gov (United States)

Gaschen, Lorrie; Kircher, Patrick

2007-08-01

Sonography is an important diagnostic tool to examine the gastrointestinal tract of dogs with chronic diarrhea. Two-dimensional grayscale ultrasound parameters to assess for various enteropathies primarily focus on wall thickness and layering. Mild, generalized thickening of the intestinal wall with maintenance of the wall layering is common in inflammatory bowel disease. Quantitative and semi-quantitative spectral Doppler arterial waveform analysis can be utilized for various enteropathies, including inflammatory bowel disease and food allergies. Dogs with inflammatory bowel disease have inadequate hemodynamic responses during digestion of food. Dogs with food allergies have prolonged vasodilation and lower resistive and pulsatility indices after eating allergen-inducing foods.

A new method for three-dimensional laparoscopic ultrasound model reconstruction

DEFF Research Database (Denmark)

Fristrup, C W; Pless, T; Durup, J

2004-01-01

BACKGROUND: Laparoscopic ultrasound is an important modality in the staging of gastrointestinal tumors. Correct staging depends on good spatial understanding of the regional tumor infiltration. Three-dimensional (3D) models may facilitate the evaluation of tumor infiltration. The aim of the study...... accuracy of the new method was tested ex vivo, and the clinical feasibility was tested on a small series of patients. RESULTS: Both electromagnetic tracked reconstructions and the new 3D method gave good volumetric information with no significant difference. Clinical use of the new 3D method showed...

Ultrasound -- Pelvis

Medline Plus

Full Text Available ... investigation of the uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries ... abnormal uterine bleeding Some physicians also use 3-D ultrasound or sonohysterography for patients with infertility. In ...

Radiological evaluation of the fetal face using three-dimensional ultrasound imaging

Directory of Open Access Journals (Sweden)

Bäumler M

2012-12-01

Full Text Available Marcel Bäumler,1–3 Michèle Bigorre,1,4 Jean-Michel Faure1,51CHU Montpellier, Centre de Compétence des Fentes Faciales, Hôpital Lapeyronie, Montpellier, 2Clinique du Parc, Imagerie de la Femme, Castelnau-le-Lez, 3Cabinet de Radiologie du Trident, Lunel, 4CHU Service de Chirurgie Plastique Pédiatrique, Hôpital Lapeyronie, Montpellier, 5CHU Montpellier, Service de Gynécologie-Obstétrique, Hôpital Arnaud de Villeneuve, Montpellier, FranceAbstract: This paper reviews screening and three-dimensional diagnostic ultrasound imaging of the fetal face. The different techniques available for analyzing biometric and morphological items of the profile, eyes, ears, lips, and hard and soft palate are commented on and briefly compared with the respective bi-dimensional techniques. The available literature supports the use of three-dimensional ultrasound in difficult prenatal diagnostic conditions because of its diagnostic accuracy, enabling improved safety of perinatal care. Globally, a marked increase has been observed in the accuracy of three-dimensional ultrasound in comparison with the bi-dimensional approach. Because there is no consensus about the performance of the different three-dimensional techniques, future studies are needed in order to compare them and to find the best technique for analysis of each of the respective facial elements. Universal prenatal standards may integrate these potential new findings in the future. At this time, the existing guidelines for prenatal facial screening should not be changed.Keywords: prenatal three-dimensional ultrasound, prenatal screening, prenatal diagnosis, cleft lip and palate, fetal profile, retrognathism

A quantitative analysis of two-dimensional manually segmented transrectal ultrasound axial images in planning high dose rate brachytherapy for prostate cancer

Directory of Open Access Journals (Sweden)

Dabić-Stanković Kata

2017-01-01

Full Text Available Background/Aim. Prostate delineation, pre-planning and catheter implantation procedures, in high-dose rate brachytherapy (HDR-BT, are commonly based on the prostate manually segmented transrectal ultrasound (TRUS images. The aim of this study was to quantitatively analyze the consistency of prostate capsule delineation, done by a single therapist, prior to each HDR-BT fraction and the changes in the shape of the prostate capsule during HDR-BT, using two dimensional (2D TRUS axial image. Methods. A group of 16 patients were treated at the Medical System Belgrade Brachytherapy Department with definitive HDRBT. The total applied median dose of 52 Gy was divided into four individual fractions, each fraction being delivered 2– 3 weeks apart. Real time prostate axial visualization and the manual segmentation prior to each fraction were performed using B-K Medical ultrasound. Quantitative analyses, analysis of an area and shape were applied on 2D-TRUS axial images of the prostate. Area analyses were used to calculate the average value of the cross-sectional area of the prostate image. The parameters of the prostate shape, the fractal dimension and the circularity ratio of the prostate capsule contour were estimated at the maximum axial cross section of the prostate image. Results. The sample group consisted of four phases, each phase being performed prior to the first, second, third and fourth HDR-BT fraction, respectively. Statistical analysis showed that during HDR-BT fractions there were no significant differences in the average value of area, as well as in the maximum shape of prostate capsule. Conclusions. Quantitative analysis of TRUS axial prostate segmented images shows a successful capsule delineation in the series of manually segmented TRUS images, and the prostate maximum shape remaining unchanged during HDR-BT fractions.

4D ultrasound and 3D MRI registration of beating heart

International Nuclear Information System (INIS)

Herlambang, N.; Matsumiya, K.; Masamune, K.; Dohi, T.; Liao, H.; Tsukihara, H.; Takamoto, S.

2007-01-01

To realize intra-cardiac surgery without cardio-pulmonary bypass, a medical imaging technique with both high image quality and data acquisition rate that is fast enough to follow heart beat movements is required. In this research, we proposed a method that utilized the image quality of MRI and the speed of ultrasound. We developed a 4D image reconstruction method using image registration of 3D MRI and 4D ultrasound images. The registration method consists of rigid registration between 3D MRI and 3D ultrasound with the same heart beat phase, and non-rigid registration between 3D ultrasound images from different heart beat phases. Non-rigid registration was performed with B-spline based registration using variable spring model. In phantom experiment using balloon phantom, registration accuracy was less than 2 mm for total heart volume variation range of 10%. We applied our registration method on 3D MRI and 4D ultrasound images of a volunteer's beating heart data and confirmed through visual observation that heart beat pattern was well reproduced. (orig.)

Advanced 3-D Ultrasound Imaging

DEFF Research Database (Denmark)

Rasmussen, Morten Fischer

The main purpose of the PhD project was to develop methods that increase the 3-D ultrasound imaging quality available for the medical personnel in the clinic. Acquiring a 3-D volume gives the medical doctor the freedom to investigate the measured anatomy in any slice desirable after the scan has...... been completed. This allows for precise measurements of organs dimensions and makes the scan more operator independent. Real-time 3-D ultrasound imaging is still not as widespread in use in the clinics as 2-D imaging. A limiting factor has traditionally been the low image quality achievable using...... a channel limited 2-D transducer array and the conventional 3-D beamforming technique, Parallel Beamforming. The first part of the scientific contributions demonstrate that 3-D synthetic aperture imaging achieves a better image quality than the Parallel Beamforming technique. Data were obtained using both...

2D shear-wave ultrasound elastography (SWE) evaluation of ablation zone following radiofrequency ablation of liver lesions: is it more accurate?

Science.gov (United States)

Bo, Xiao W; Li, Xiao L; Guo, Le H; Li, Dan D; Liu, Bo J; Wang, Dan; He, Ya P; Xu, Xiao H

2016-01-01

Objective: To evaluate the usefulness of two-dimensional quantitative ultrasound shear-wave elastography (2D-SWE) [i.e. virtual touch imaging quantification (VTIQ)] in assessing the ablation zone after radiofrequency ablation (RFA) for ex vivo swine livers. Methods: RFA was performed in 10 pieces of fresh ex vivo swine livers with a T20 electrode needle and 20-W output power. Conventional ultrasound, conventional strain elastography (SE) and VTIQ were performed to depict the ablation zone 0 min, 10 min, 30 min and 60 min after ablation. On VTIQ, the ablation zones were evaluated qualitatively by evaluating the shear-wave velocity (SWV) map and quantitatively by measuring the SWV. The ultrasound, SE and VTIQ results were compared against gross pathological and histopathological specimens. Results: VTIQ SWV maps gave more details about the ablation zone, the central necrotic zone appeared as red, lateral necrotic zone as green and transitional zone as light green, from inner to exterior, while the peripheral unablated liver appeared as blue. Conventional ultrasound and SE, however, only marginally depicted the whole ablation zone. The volumes of the whole ablation zone (central necrotic zone + lateral necrotic zone + transitional zone) and necrotic zone (central necrotic zone + lateral necrotic zone) measured by VTIQ showed excellent correlation (r = 0.915, p  0.05). Conclusion: The quantitative 2D-SWE of VTIQ is useful for the depiction of the ablation zone after RFA and it facilitates discrimination of different areas in the ablation zone qualitatively and quantitatively. This elastography technique might be useful for the therapeutic response evaluation instantly after RFA. Advances in knowledge: A new quantitative 2D-SWE (i.e. VTIQ) for evaluation treatment response after RFA is demonstrated. It facilitates discrimination of the different areas in the ablation zone qualitatively and quantitatively and may be useful for the therapeutic

Analysis of contact stiffness in ultrasound atomic force microscopy: three-dimensional time-dependent ultrasound modeling

International Nuclear Information System (INIS)

Piras, Daniele; Sadeghian, Hamed

2017-01-01

Ultrasound atomic force microscopy (US-AFM) has been used for subsurface imaging of nanostructures. The contact stiffness variations have been suggested as the origin of the image contrast. Therefore, to analyze the image contrast, the local changes in the contact stiffness due to the presence of subsurface features should be calculated. So far, only static simulations have been conducted to analyze the local changes in the contact stiffness and, consequently, the contrast in US-AFM. Such a static approach does not fully represent the real US-AFM experiment, where an ultrasound wave is launched either into the sample or at the tip, which modulates the contact stiffness. This is a time-dependent nonlinear dynamic problem rather than a static and stationary one. This paper presents dynamic 3D ultrasound analysis of contact stiffness in US-AFM (in contrast to static analysis) to realistically predict the changes in contact stiffness and thus the changes in the subsurface image contrast. The modulation frequency also influences the contact stiffness variations and, thus, the image contrast. The three-dimensional time-dependent ultrasound analysis will greatly aid in the contrast optimization of subsurface nano imaging with US-AFM. (paper)

Reproducibility of three-dimensional ultrasound for the measurement of a niche in a caesarean scar and assessment of its shape

NARCIS (Netherlands)

Bij de Vaate, A.J.M.; Linskens, I.H.; van der Voet, L.F.; Twisk, J.W.R.; Brölmann, H.A.M.; Huirne, J.A.F.

2015-01-01

Abstract Objective To evaluate the inter- and intraobserver agreement for measurement of the size and volume of a niche and assessment of the shape, with the use of three-dimensional (3D) ultrasound. Study design In this reproducibility study, 20 3D ultrasound volumes of uteri with a niche were

A 3D freehand ultrasound system for multi-view reconstructions from sparse 2D scanning planes.

Science.gov (United States)

Yu, Honggang; Pattichis, Marios S; Agurto, Carla; Beth Goens, M

2011-01-20

A significant limitation of existing 3D ultrasound systems comes from the fact that the majority of them work with fixed acquisition geometries. As a result, the users have very limited control over the geometry of the 2D scanning planes. We present a low-cost and flexible ultrasound imaging system that integrates several image processing components to allow for 3D reconstructions from limited numbers of 2D image planes and multiple acoustic views. Our approach is based on a 3D freehand ultrasound system that allows users to control the 2D acquisition imaging using conventional 2D probes.For reliable performance, we develop new methods for image segmentation and robust multi-view registration. We first present a new hybrid geometric level-set approach that provides reliable segmentation performance with relatively simple initializations and minimum edge leakage. Optimization of the segmentation model parameters and its effect on performance is carefully discussed. Second, using the segmented images, a new coarse to fine automatic multi-view registration method is introduced. The approach uses a 3D Hotelling transform to initialize an optimization search. Then, the fine scale feature-based registration is performed using a robust, non-linear least squares algorithm. The robustness of the multi-view registration system allows for accurate 3D reconstructions from sparse 2D image planes. Volume measurements from multi-view 3D reconstructions are found to be consistently and significantly more accurate than measurements from single view reconstructions. The volume error of multi-view reconstruction is measured to be less than 5% of the true volume. We show that volume reconstruction accuracy is a function of the total number of 2D image planes and the number of views for calibrated phantom. In clinical in-vivo cardiac experiments, we show that volume estimates of the left ventricle from multi-view reconstructions are found to be in better agreement with clinical

Three-dimensional isotropic T2-weighted cervical MRI at 3 T: Comparison with two-dimensional T2-weighted sequences

International Nuclear Information System (INIS)

Kwon, J.W.; Yoon, Y.C.; Choi, S.-H.

2012-01-01

Aim: To compare three-dimensional (3D) isotropic T2-weighted magnetic resonance imaging (MRI) sequences and reformation with two-dimensional (2D) T2-weighted sequences regarding image quality of the cervical spine at 3 T. Materials and methods: A phantom study was performed using a water-filled cylinder. The signal-to-noise and image homogeneity were evaluated. Fourteen (n = 14) volunteers were examined at 3 T using 3D isotropic T2-weighted sagittal and conventional 2D T2-weighted sagittal, axial, and oblique sagittal MRI. Multiplanar reformation (MPR) of the 3D T2-weighted sagittal dataset was performed simultaneously with image evaluation. In addition to artefact assessment, the visibility of anatomical structures in the 3D and 2D sequences was qualitatively assessed by two radiologists independently. Cohen’s kappa and Wilcoxon signed rank test were used for the statistical analysis. Result: The 3D isotropic T2-weighted sequence resulted in the highest signal-to-noise ratio (SNR) and lowest non-uniformity (NU) among the sequences in the phantom study. Quantitative evaluation revealed lower NU values of the cerebrospinal fluid (CSF) and muscles in 2D T2-weighted sagittal sequences compared to the 3D volume isotropic turbo spin-echo acquisition (VISTA) sequence. The other NU values revealed no statistically significant difference between the 2D turbo spin-echo (TSE) and 3D VISTA sequences (0.059 < p < 0.959). 3D VISTA images showed significantly fewer CSF flow artefacts (p < 0.001) and better delineated intradural nerve rootlets (p = 0.001) and neural foramina (p = 0.016) compared to 2D sequences. Conclusion: A 3D T2 weighted sequence is superior to conventional 2D sequences for the delineation of intradural nerve rootlets and neural foramina and is less affected by CSF flow artefacts.

First trimester diagnosis of parapagus diprosopus dibrachius dipus twins with cranirachischisis totalis by three-dimensional ultrasound.

Science.gov (United States)

Ülker, Kahraman; Akyer, Şahika P; Temur, İsmail; Tan, Temel; Karaca, Mehmet; Adıgüzel, Esat; Gül, Abdülaziz

2012-02-01

Parapagus (laterally fused), diprosopus (two faces), dibrachius (two upper extremities), dipus (two lower extremities) conjoined twinning is extremely rare. The coexistence of anencephaly with a contiguous spinal defect (craniorachischisis totalis) makes the present case one of the rarest of the published cases. In our case, it was difficult to make the final diagnosis by two-dimensional abdominal and vaginal ultrasound. Three-dimensional ultrasound was helpful for final diagnosis and post-abortal examination confirmed the prenatal ultrasound diagnosis. The heart, diaphragm, liver and perineum were all united. Fine dissection of the heart showed four vessels arising from the ventricles and a membranous type ventricular septal defect. © 2011 The Authors. Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology.

Novel target design algorithm for two-dimensional optical storage (TwoDOS)

NARCIS (Netherlands)

Huang, Li; Chong, T.C.; Vijaya Kumar, B.V.K.; Kobori, H.

2004-01-01

In this paper we introduce the Hankel transform based channel model of Two-Dimensional Optical Storage (TwoDOS) system. Based on this model, the two-dimensional (2D) minimum mean-square error (MMSE) equalizer has been derived and applied to some simple but common cases. The performance of the 2D

The simulation of a two-dimensional (2D) transport problem in a rectangular region with Lattice Boltzmann method with two-relaxation-time

Science.gov (United States)

Sugiyanto, S.; Hardyanto, W.; Marwoto, P.

2018-03-01

Transport phenomena are found in many problems in many engineering and industrial sectors. We analyzed a Lattice Boltzmann method with Two-Relaxation Time (LTRT) collision operators for simulation of pollutant moving through the medium as a two-dimensional (2D) transport problem in a rectangular region model. This model consists of a 2D rectangular region with 54 length (x), 27 width (y), and it has isotropic homogeneous medium. Initially, the concentration is zero and is distributed evenly throughout the region of interest. A concentration of 1 is maintained at 9 < y < 18, whereas the concentration of zero is maintained at 0 < y < 9 and 18 < y < 27. A specific discharge (Darcy velocity) of 1.006 is assumed. A diffusion coefficient of 0.8333 is distributed uniformly with a uniform porosity of 0.35. A computer program is written in MATLAB to compute the concentration of pollutant at any specified place and time. The program shows that LTRT solution with quadratic equilibrium distribution functions (EDFs) and relaxation time τa=1.0 are in good agreement result with other numerical solutions methods such as 3DLEWASTE (Hybrid Three-dimensional Lagrangian-Eulerian Finite Element Model of Waste Transport Through Saturated-Unsaturated Media) obtained by Yeh and 3DFEMWATER-LHS (Three-dimensional Finite Element Model of Water Flow Through Saturated-Unsaturated Media with Latin Hypercube Sampling) obtained by Hardyanto.

The Application of Ultrasound in 3D Bio-Printing.

Science.gov (United States)

Zhou, Yufeng

2016-05-05

Three-dimensional (3D) bioprinting is an emerging and promising technology in tissue engineering to construct tissues and organs for implantation. Alignment of self-assembly cell spheroids that are used as bioink could be very accurate after droplet ejection from bioprinter. Complex and heterogeneous tissue structures could be built using rapid additive manufacture technology and multiple cell lines. Effective vascularization in the engineered tissue samples is critical in any clinical application. In this review paper, the current technologies and processing steps (such as printing, preparation of bioink, cross-linking, tissue fusion and maturation) in 3D bio-printing are introduced, and their specifications are compared with each other. In addition, the application of ultrasound in this novel field is also introduced. Cells experience acoustic radiation force in ultrasound standing wave field (USWF) and then accumulate at the pressure node at low acoustic pressure. Formation of cell spheroids by this method is within minutes with uniform size and homogeneous cell distribution. Neovessel formation from USWF-induced endothelial cell spheroids is significant. Low-intensity ultrasound could enhance the proliferation and differentiation of stem cells. Its use is at low cost and compatible with current bioreactor. In summary, ultrasound application in 3D bio-printing may solve some challenges and enhance the outcomes.

The Application of Ultrasound in 3D Bio-Printing

Directory of Open Access Journals (Sweden)

Yufeng Zhou

2016-05-01

Full Text Available Three-dimensional (3D bioprinting is an emerging and promising technology in tissue engineering to construct tissues and organs for implantation. Alignment of self-assembly cell spheroids that are used as bioink could be very accurate after droplet ejection from bioprinter. Complex and heterogeneous tissue structures could be built using rapid additive manufacture technology and multiple cell lines. Effective vascularization in the engineered tissue samples is critical in any clinical application. In this review paper, the current technologies and processing steps (such as printing, preparation of bioink, cross-linking, tissue fusion and maturation in 3D bio-printing are introduced, and their specifications are compared with each other. In addition, the application of ultrasound in this novel field is also introduced. Cells experience acoustic radiation force in ultrasound standing wave field (USWF and then accumulate at the pressure node at low acoustic pressure. Formation of cell spheroids by this method is within minutes with uniform size and homogeneous cell distribution. Neovessel formation from USWF-induced endothelial cell spheroids is significant. Low-intensity ultrasound could enhance the proliferation and differentiation of stem cells. Its use is at low cost and compatible with current bioreactor. In summary, ultrasound application in 3D bio-printing may solve some challenges and enhance the outcomes.

Feasibility of Ultrasound-Based Computational Fluid Dynamics as a Mitral Valve Regurgitation Quantification Technique: Comparison with 2-D and 3-D Proximal Isovelocity Surface Area-Based Methods.

Science.gov (United States)

Jamil, Muhammad; Ahmad, Omar; Poh, Kian Keong; Yap, Choon Hwai

2017-07-01

Current Doppler echocardiography quantification of mitral regurgitation (MR) severity has shortcomings. Proximal isovelocity surface area (PISA)-based methods, for example, are unable to account for the fact that ultrasound Doppler can measure only one velocity component: toward or away from the transducer. In the present study, we used ultrasound-based computational fluid dynamics (Ub-CFD) to quantify mitral regurgitation and study its advantages and disadvantages compared with 2-D and 3-D PISA methods. For Ub-CFD, patient-specific mitral valve geometry and velocity data were obtained from clinical ultrasound followed by 3-D CFD simulations at an assumed flow rate. We then obtained the average ratio of the ultrasound Doppler velocities to CFD velocities in the flow convergence region, and scaled CFD flow rate with this ratio as the final measured flow rate. We evaluated Ub-CFD, 2-D PISA and 3-D PISA with an in vitro flow loop, which featured regurgitation flow through (i) a simplified flat plate with round orifice and (ii) a 3-D printed realistic mitral valve and regurgitation orifice. The Ub-CFD and 3-D PISA methods had higher precision than the 2-D PISA method. Ub-CFD had consistent accuracy under all conditions tested, whereas 2-D PISA had the lowest overall accuracy. In vitro investigations indicated that the accuracy of 2-D and 3-D PISA depended significantly on the choice of aliasing velocity. Evaluation of these techniques was also performed for two clinical cases, and the dependency of PISA on aliasing velocity was similarly observed. Ub-CFD was robustly accurate and precise and has promise for future translation to clinical practice. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

SUPRA: open-source software-defined ultrasound processing for real-time applications : A 2D and 3D pipeline from beamforming to B-mode.

Science.gov (United States)

Göbl, Rüdiger; Navab, Nassir; Hennersperger, Christoph

2018-06-01

Research in ultrasound imaging is limited in reproducibility by two factors: First, many existing ultrasound pipelines are protected by intellectual property, rendering exchange of code difficult. Second, most pipelines are implemented in special hardware, resulting in limited flexibility of implemented processing steps on such platforms. With SUPRA, we propose an open-source pipeline for fully software-defined ultrasound processing for real-time applications to alleviate these problems. Covering all steps from beamforming to output of B-mode images, SUPRA can help improve the reproducibility of results and make modifications to the image acquisition mode accessible to the research community. We evaluate the pipeline qualitatively, quantitatively, and regarding its run time. The pipeline shows image quality comparable to a clinical system and backed by point spread function measurements a comparable resolution. Including all processing stages of a usual ultrasound pipeline, the run-time analysis shows that it can be executed in 2D and 3D on consumer GPUs in real time. Our software ultrasound pipeline opens up the research in image acquisition. Given access to ultrasound data from early stages (raw channel data, radiofrequency data), it simplifies the development in imaging. Furthermore, it tackles the reproducibility of research results, as code can be shared easily and even be executed without dedicated ultrasound hardware.

Ultrasound directed self-assembly of three-dimensional user-specified patterns of particles in a fluid medium

Science.gov (United States)

Prisbrey, M.; Greenhall, J.; Guevara Vasquez, F.; Raeymaekers, B.

2017-01-01

We use ultrasound directed self-assembly to organize particles dispersed in a fluid medium into a three-dimensional (3D) user-specified pattern. The technique employs ultrasound transducers that line the boundary of a fluid reservoir to create a standing ultrasound wave field. The acoustic radiation force associated with the wave field drives particles dispersed in the fluid medium into organized patterns, assuming that the particles are much smaller than the wavelength and do not interact with each other. We have theoretically derived a direct solution method to calculate the ultrasound transducer operating parameters that are required to assemble a user-specified 3D pattern of particles in a fluid reservoir of arbitrary geometry. We formulate the direct solution method as a constrained optimization problem that reduces to eigendecomposition. We experimentally validate the solution method by assembling 3D patterns of carbon nanoparticles in a water reservoir and observe good quantitative agreement between theory and experiment. Additionally, we demonstrate the versatility of the solution method by simulating ultrasound directed self-assembly of complex 3D patterns of particles. The method works for any 3D simple, closed fluid reservoir geometry in combination with any arrangement of ultrasound transducers and enables employing ultrasound directed self-assembly in a myriad of engineering applications, including biomedical and materials fabrication processes.

Enhanced job control language procedures for the SIMSYS2D two-dimensional water-quality simulation system

Science.gov (United States)

Karavitis, G.A.

1984-01-01

The SIMSYS2D two-dimensional water-quality simulation system is a large-scale digital modeling software system used to simulate flow and transport of solutes in freshwater and estuarine environments. Due to the size, processing requirements, and complexity of the system, there is a need to easily move the system and its associated files between computer sites when required. A series of job control language (JCL) procedures was written to allow transferability between IBM and IBM-compatible computers. (USGS)

General Ultrasound Imaging

Medline Plus

Full Text Available ... medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ...

4D ultrasound imaging - ethically justifiable in India?

Science.gov (United States)

Indiran, Venkatraman

2017-01-01

Four-dimensional (4D) ultrasound (real-time volume sonography), which has been used in the West since the last decade for the determination of gender as well as for bonding and entertainment of the parents, has become widely available in India in this decade. Here, I would like to discuss the ethical issues associated with 4D ultrasonography in India. These are self-referral, the use of the technology for non-medical indications, a higher possibility of the disclosure of the foetus' gender and safety concerns.

Clinical utility of three-dimensional contrast-enhanced ultrasound in the differentiation between noninvasive and invasive neoplasms of urinary bladder.

Science.gov (United States)

Li, Qiu-yang; Tang, Jie; He, En-hui; Li, Yan-mi; Zhou, Yun; Zhang, Xu; Chen, Guangfu

2012-11-01

The purpose of this study was to evaluate the effectiveness of three-dimensional contrast-enhanced ultrasound in differentiating invasive and noninvasive neoplasms of urinary bladder. A total of 60 lesions in 60 consecutive patients with bladder tumors received three dimensional ultrasonography, low acoustic power contrast enhanced ultrasonography and low acoustic power three-dimensional contrast-enhanced ultrasound examination. The IU22 ultrasound scanner and a volume transducer were used and the ultrasound contrast agent was SonoVue. The contrast-specific sonographic imaging modes were PI (pulse inversion) and PM (power modulation). The three dimensional ultrasonography, contrast enhanced ultrasonography, and three-dimensional contrast-enhanced ultrasound images were independently reviewed by two readers who were not in the images acquisition. Images were analyzed off-site. A level of confidence in the diagnosis of tumor invasion of the muscle layer was assigned on a 5° scale. Receiver operating characteristic analysis was used to assess overall confidence in the diagnosis of muscle invasion by tumor. Kappa values were used to assess inter-readers agreement. Histologic diagnosis was obtained for all patients. Final pathologic staging revealed 44 noninvasive tumors and 16 invasive tumors. Three-dimensional contrast-enhanced ultrasound depicted all 16 muscle-invasive tumors. The diagnostic performance of three-dimensional contrast-enhanced ultrasound was better than those of three dimensional ultrasonography and contrast enhanced ultrasonography. The receiver operating characteristic curves were 0.976 and 0.967 for three-dimensional contrast-enhanced ultrasound, those for three dimensional ultrasonography were 0.881 and 0.869, those for contrast enhanced ultrasonography were 0.927 and 0.929. The kappa values in the three dimensional ultrasonography, contrast enhanced ultrasonography and three-dimensional contrast-enhanced ultrasound for inter-reader agreements

Clinical utility of three-dimensional contrast-enhanced ultrasound in the differentiation between noninvasive and invasive neoplasms of urinary bladder

International Nuclear Information System (INIS)

Li, Qiu-yang; Tang, Jie; He, En-hui; Li, Yan-mi; Zhou, Yun; Zhang, Xu; Chen, Guangfu

2012-01-01

Objectives: The purpose of this study was to evaluate the effectiveness of three-dimensional contrast-enhanced ultrasound in differentiating invasive and noninvasive neoplasms of urinary bladder. Methods: A total of 60 lesions in 60 consecutive patients with bladder tumors received three dimensional ultrasonography, low acoustic power contrast enhanced ultrasonography and low acoustic power three-dimensional contrast-enhanced ultrasound examination. The IU22 ultrasound scanner and a volume transducer were used and the ultrasound contrast agent was SonoVue. The contrast-specific sonographic imaging modes were PI (pulse inversion) and PM (power modulation). The three dimensional ultrasonography, contrast enhanced ultrasonography, and three-dimensional contrast-enhanced ultrasound images were independently reviewed by two readers who were not in the images acquisition. Images were analyzed off-site. A level of confidence in the diagnosis of tumor invasion of the muscle layer was assigned on a 5° scale. Receiver operating characteristic analysis was used to assess overall confidence in the diagnosis of muscle invasion by tumor. Kappa values were used to assess inter-readers agreement. Histologic diagnosis was obtained for all patients. Results: Final pathologic staging revealed 44 noninvasive tumors and 16 invasive tumors. Three-dimensional contrast-enhanced ultrasound depicted all 16 muscle-invasive tumors. The diagnostic performance of three-dimensional contrast-enhanced ultrasound was better than those of three dimensional ultrasonography and contrast enhanced ultrasonography. The receiver operating characteristic curves were 0.976 and 0.967 for three-dimensional contrast-enhanced ultrasound, those for three dimensional ultrasonography were 0.881 and 0.869, those for contrast enhanced ultrasonography were 0.927 and 0.929. The kappa values in the three dimensional ultrasonography, contrast enhanced ultrasonography and three-dimensional contrast-enhanced ultrasound

Multiple-canister flow and transport code in 2-dimensional space. MCFT2D: user's manual

International Nuclear Information System (INIS)

Lim, Doo-Hyun

2006-03-01

A two-dimensional numerical code, MCFT2D (Multiple-Canister Flow and Transport code in 2-Dimensional space), has been developed for groundwater flow and radionuclide transport analyses in a water-saturated high-level radioactive waste (HLW) repository with multiple canisters. A multiple-canister configuration and a non-uniform flow field of the host rock are incorporated in the MCFT2D code. Effects of heterogeneous flow field of the host rock on migration of nuclides can be investigated using MCFT2D. The MCFT2D enables to take into account the various degrees of the dependency of canister configuration for nuclide migration in a water-saturated HLW repository, while the dependency was assumed to be either independent or perfectly dependent in previous studies. This report presents features of the MCFT2D code, numerical simulation using MCFT2D code, and graphical representation of the numerical results. (author)

Two-Stage Regularized Linear Discriminant Analysis for 2-D Data.

Science.gov (United States)

Zhao, Jianhua; Shi, Lei; Zhu, Ji

2015-08-01

Fisher linear discriminant analysis (LDA) involves within-class and between-class covariance matrices. For 2-D data such as images, regularized LDA (RLDA) can improve LDA due to the regularized eigenvalues of the estimated within-class matrix. However, it fails to consider the eigenvectors and the estimated between-class matrix. To improve these two matrices simultaneously, we propose in this paper a new two-stage method for 2-D data, namely a bidirectional LDA (BLDA) in the first stage and the RLDA in the second stage, where both BLDA and RLDA are based on the Fisher criterion that tackles correlation. BLDA performs the LDA under special separable covariance constraints that incorporate the row and column correlations inherent in 2-D data. The main novelty is that we propose a simple but effective statistical test to determine the subspace dimensionality in the first stage. As a result, the first stage reduces the dimensionality substantially while keeping the significant discriminant information in the data. This enables the second stage to perform RLDA in a much lower dimensional subspace, and thus improves the two estimated matrices simultaneously. Experiments on a number of 2-D synthetic and real-world data sets show that BLDA+RLDA outperforms several closely related competitors.

Crouzon syndrome associated with acanthosis nigricans: prenatal 2D and 3D ultrasound findings and postnatal 3D CT findings

DEFF Research Database (Denmark)

Nørgaard, P.; Hagen, CP; Hove, H.

2012-01-01

Crouzon syndrome with acanthosis nigricans (CAN) is a very rare condition with an approximate prevalence of 1 per 1 million newborns. We add the first report on prenatal 2D and 3D ultrasound findings in CAN. In addition we present the postnatal 3D CT findings. The diagnosis was confirmed...

Two-dimensional sum-frequency generation (2D SFG) reveals structure and dynamics of a surface-bound peptide

Science.gov (United States)

Laaser, Jennifer E.; Skoff, David R.; Ho, Jia-Jung; Joo, Yongho; Serrano, Arnaldo L.; Steinkruger, Jay D.; Gopalan, Padma; Gellman, Samuel H.; Zanni, Martin T.

2014-01-01

Surface-bound polypeptides and proteins are increasingly used to functionalize inorganic interfaces such as electrodes, but their structural characterization is exceedingly difficult with standard technologies. In this paper, we report the first two-dimensional sum-frequency generation (2D SFG) spectra of a peptide monolayer, which is collected by adding a mid-IR pulse shaper to a standard femtosecond SFG spectrometer. On a gold surface, standard FTIR spectroscopy is inconclusive about the peptide structure because of solvation-induced frequency shifts, but the 2D lineshapes, anharmonic shifts, and lifetimes obtained from 2D SFG reveal that the peptide is largely α-helical and upright. Random coil residues are also observed, which do not themselves appear in SFG spectra due to their isotropic structural distribution, but which still absorb infrared light and so can be detected by cross-peaks in 2D SFG spectra. We discuss these results in the context of peptide design. Because of the similar way in which the spectra are collected, these 2D SFG spectra can be directly compared to 2D IR spectra, thereby enabling structural interpretations of surface-bound peptides and biomolecules based on the well-studied structure/2D IR spectra relationships established from soluble proteins. PMID:24372101

Online 4D ultrasound guidance for real-time motion compensation by MLC tracking.

Science.gov (United States)

Ipsen, Svenja; Bruder, Ralf; O'Brien, Rick; Keall, Paul J; Schweikard, Achim; Poulsen, Per R

2016-10-01

With the trend in radiotherapy moving toward dose escalation and hypofractionation, the need for highly accurate targeting increases. While MLC tracking is already being successfully used for motion compensation of moving targets in the prostate, current real-time target localization methods rely on repeated x-ray imaging and implanted fiducial markers or electromagnetic transponders rather than direct target visualization. In contrast, ultrasound imaging can yield volumetric data in real-time (3D + time = 4D) without ionizing radiation. The authors report the first results of combining these promising techniques-online 4D ultrasound guidance and MLC tracking-in a phantom. A software framework for real-time target localization was installed directly on a 4D ultrasound station and used to detect a 2 mm spherical lead marker inside a water tank. The lead marker was rigidly attached to a motion stage programmed to reproduce nine characteristic tumor trajectories chosen from large databases (five prostate, four lung). The 3D marker position detected by ultrasound was transferred to a computer program for MLC tracking at a rate of 21.3 Hz and used for real-time MLC aperture adaption on a conventional linear accelerator. The tracking system latency was measured using sinusoidal trajectories and compensated for by applying a kernel density prediction algorithm for the lung traces. To measure geometric accuracy, static anterior and lateral conformal fields as well as a 358° arc with a 10 cm circular aperture were delivered for each trajectory. The two-dimensional (2D) geometric tracking error was measured as the difference between marker position and MLC aperture center in continuously acquired portal images. For dosimetric evaluation, VMAT treatment plans with high and low modulation were delivered to a biplanar diode array dosimeter using the same trajectories. Dose measurements with and without MLC tracking were compared to a static reference dose using 3%/3 mm and 2%/2

A needle guidance system for biopsy and therapy using two-dimensional ultrasound

International Nuclear Information System (INIS)

Bluvol, Nathan; Sheikh, Allison; Kornecki, Anat; Del Rey Fernandez, David; Downey, Donal; Fenster, Aaron

2008-01-01

Image-guided needle biopsies are currently used to provide a definitive diagnosis of breast cancer; however, difficulties in tumor targeting exist as the ultrasound (United States) scan plane and biopsy needle must remain coplanar throughout the procedure to display the actual needle tip position. The additional time associated with aligning and maintaining this coplanar relationship results in increased patient discomfort. Biopsy procedural efficiency is further hindered since needle pathway interpretation is often difficult, especially for needle insertions at large depths that usually require multiple reinsertions. The authors developed a system that would increase the speed and accuracy of current breast biopsy procedures using readily available two-dimensional (2D) US technology. This system is composed of a passive articulated mechanical arm that attaches to a 2D US transducer. The arm is connected to a computer through custom electronics and software, which were developed as an interface for tracking the positioning of the mechanical components in real time. The arm couples to the biopsy needle and provides visual guidance for the physician performing the procedure in the form of a real-time projected needle pathway overlay on an US image of the breast. An agar test phantom, with stainless steel targets interspersed randomly throughout, was used to validate needle trajectory positioning accuracy. The biopsy needle was guided by both the software and hardware components to the targets. The phantom, with the needle inserted and device decoupled, was placed in an x-ray stereotactic mammography (SM) machine. The needle trajectory and bead target locations were determined in three dimensions from the SM images. Results indicated a mean needle trajectory accuracy error of 0.75±0.42 mm. This is adequate to sample lesions that are <2 mm in diameter. Chicken tissue test phantoms were used to compare core needle biopsy procedure times between experienced radiologists

Two-dimensional orbital ordering in d{sup 1} Mott insulator Sr{sub 2}VO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Viennois, R; Giannini, E; Teyssier, J; Elia, J; Van der Marel, D [DPMC, Universite de Geneve, 24 quai Ernest Ansermet, CH-1211 Geneve (Switzerland); Deisenhofer, J, E-mail: Romain.Viennois@unige.c [Institute of Physics, University of Augsburg, Augsburg (Germany)

2010-01-15

The Mott insulator Sr{sub 2}VO{sub 4} is a unique d{sup 1} two-dimensional compound exhibiting an orbital ordering transition. In addition to the orbital ordering transition at about 100 K, we discovered a ferromagnetic transition below 10 K, thus confirming the predictions of recent band structure calculations. The magnetic properties proved to be strongly sensitive to the material purity, the actual oxygen stoichiometry and the crystallographic parameters. An additional transition is observed at 125 K, which is believed to be due to structural modifications.

Three-Dimensional Simulation of Ultrasound-Induced Microalgal Cell Disruption.

Science.gov (United States)

Wang, M; Yuan, W; Hale, Andy

2016-03-01

The three-dimensional distribution (x, y, and z) of ultrasound-induced microalgal cell disruption in a sonochemical reactor was predicted by solving the Helmholtz equation using a three-dimensional acoustic module in the COMSOL Multiphysics software. The simulated local ultrasound pressure at any given location (x, y, and z) was found to correlate with cell disruption of a freshwater alga, Scenedesmus dimorphus, represented by the change of algal cell particle/debris concentration, chlorophyll-a fluorescence density (CAFD), and Nile red stained lipid fluorescence density (LFD), which was also validated by the model reaction of potassium iodide oxidation (the Weissler reaction). Furthermore, the effect of ultrasound power intensity and processing duration on algal cell disruption was examined to address the limitation of the model.

Three-dimensional ultrasound image-guided robotic system for accurate microwave coagulation of malignant liver tumours.

Science.gov (United States)

Xu, Jing; Jia, Zhen-zhong; Song, Zhang-jun; Yang, Xiang-dong; Chen, Ken; Liang, Ping

2010-09-01

The further application of conventional ultrasound (US) image-guided microwave (MW) ablation of liver cancer is often limited by two-dimensional (2D) imaging, inaccurate needle placement and the resulting skill requirement. The three-dimensional (3D) image-guided robotic-assisted system provides an appealing alternative option, enabling the physician to perform consistent, accurate therapy with improved treatment effectiveness. Our robotic system is constructed by integrating an imaging module, a needle-driven robot, a MW thermal field simulation module, and surgical navigation software in a practical and user-friendly manner. The robot executes precise needle placement based on the 3D model reconstructed from freehand-tracked 2D B-scans. A qualitative slice guidance method for fine registration is introduced to reduce the placement error caused by target motion. By incorporating the 3D MW specific absorption rate (SAR) model into the heat transfer equation, the MW thermal field simulation module determines the MW power level and the coagulation time for improved ablation therapy. Two types of wrists are developed for the robot: a 'remote centre of motion' (RCM) wrist and a non-RCM wrist, which is preferred in real applications. The needle placement accuracies were robot with the RCM wrist was improved to 1.6 +/- 1.0 mm when real-time 2D US feedback was used in the artificial-tissue phantom experiment. By using the slice guidance method, the robot with the non-RCM wrist achieved accuracy of 1.8 +/- 0.9 mm in the ex vivo experiment; even target motion was introduced. In the thermal field experiment, a 5.6% relative mean error was observed between the experimental coagulated neurosis volume and the simulation result. The proposed robotic system holds promise to enhance the clinical performance of percutaneous MW ablation of malignant liver tumours. Copyright 2010 John Wiley & Sons, Ltd.

Follow-up on Small Abdominal Aortic Aneurysms Using Three Dimensional Ultrasound

DEFF Research Database (Denmark)

Ghulam, Q. M.; Bredahl, K. K.; Lönn, L.

2017-01-01

Objectives Rupture risk in abdominal aortic aneurysms (AAAs) is assessed using AAA diameter; yet 10% of ruptures occur in a small aneurysm. This underlines the inadequacy of diameter as a standalone parameter. In this prospective follow-up study, ultrasound determined aneurysm diameter was compared...... with aneurysm volume determined by three dimensional ultrasound (3D-US) in a group of 179 AAAs. Design This was a prospective cohort study with repeated diameter and volume measurements by 3D-US. Material and methods In total, 179 patients with small infrarenal AAAs (diameter 30–55 mm) were enrolled......L) were recorded. In post-hoc analysis, it was found that more AAAs with a stable diameter and a growing volume than AAAs with a stable diameter and volume were undergoing aortic repair during follow-up, based on the maximum diameter. Conclusion In this cohort of small AAAs, 40% of patients with a stable...

Comparison of different reconstruction algorithms for three-dimensional ultrasound imaging in a neurosurgical setting.

Science.gov (United States)

Miller, D; Lippert, C; Vollmer, F; Bozinov, O; Benes, L; Schulte, D M; Sure, U

2012-09-01

Freehand three-dimensional ultrasound imaging (3D-US) is increasingly used in image-guided surgery. During image acquisition, a set of B-scans is acquired that is distributed in a non-parallel manner over the area of interest. Reconstructing these images into a regular array allows 3D visualization. However, the reconstruction process may introduce artefacts and may therefore reduce image quality. The aim of the study is to compare different algorithms with respect to image quality and diagnostic value for image guidance in neurosurgery. 3D-US data sets were acquired during surgery of various intracerebral lesions using an integrated ultrasound-navigation device. They were stored for post-hoc evaluation. Five different reconstruction algorithms, a standard multiplanar reconstruction with interpolation (MPR), a pixel nearest neighbour method (PNN), a voxel nearest neighbour method (VNN) and two voxel based distance-weighted algorithms (VNN2 and DW) were tested with respect to image quality and artefact formation. The capability of the algorithm to fill gaps within the sample volume was investigated and a clinical evaluation with respect to the diagnostic value of the reconstructed images was performed. MPR was significantly worse than the other algorithms in filling gaps. In an image subtraction test, VNN2 and DW reliably reconstructed images even if large amounts of data were missing. However, the quality of the reconstruction improved, if data acquisition was performed in a structured manner. When evaluating the diagnostic value of reconstructed axial, sagittal and coronal views, VNN2 and DW were judged to be significantly better than MPR and VNN. VNN2 and DW could be identified as robust algorithms that generate reconstructed US images with a high diagnostic value. These algorithms improve the utility and reliability of 3D-US imaging during intraoperative navigation. Copyright © 2012 John Wiley & Sons, Ltd.

3D Tendon Strain Estimation Using High-frequency Volumetric Ultrasound Images: A Feasibility Study.

Science.gov (United States)

Carvalho, Catarina; Slagmolen, Pieter; Bogaerts, Stijn; Scheys, Lennart; D'hooge, Jan; Peers, Koen; Maes, Frederik; Suetens, Paul

2018-03-01

Estimation of strain in tendons for tendinopathy assessment is a hot topic within the sports medicine community. It is believed that, if accurately estimated, existing treatment and rehabilitation protocols can be improved and presymptomatic abnormalities can be detected earlier. State-of-the-art studies present inaccurate and highly variable strain estimates, leaving this problem without solution. Out-of-plane motion, present when acquiring two-dimensional (2D) ultrasound (US) images, is a known problem and may be responsible for such errors. This work investigates the benefit of high-frequency, three-dimensional (3D) US imaging to reduce errors in tendon strain estimation. Volumetric US images were acquired in silico, in vitro, and ex vivo using an innovative acquisition approach that combines the acquisition of 2D high-frequency US images with a mechanical guided system. An affine image registration method was used to estimate global strain. 3D strain estimates were then compared with ground-truth values and with 2D strain estimates. The obtained results for in silico data showed a mean absolute error (MAE) of 0.07%, 0.05%, and 0.27% for 3D estimates along axial, lateral direction, and elevation direction and a respective MAE of 0.21% and 0.29% for 2D strain estimates. Although 3D could outperform 2D, this does not occur in in vitro and ex vivo settings, likely due to 3D acquisition artifacts. Comparison against the state-of-the-art methods showed competitive results. The proposed work shows that 3D strain estimates are more accurate than 2D estimates but acquisition of appropriate 3D US images remains a challenge.

Preliminary assessment of one-dimensional MR elastography for use in monitoring focused ultrasound therapy

International Nuclear Information System (INIS)

Yuan Le; Glaser, Kevin J; Rouviere, Olivier; Gorny, Krzysztof R; Chen, Shigao; Manduca, Armando; Ehman, Richard L; Felmlee, Joel P

2007-01-01

The purpose of this work is to assess a fast technique that measures tissue stiffness and temperature during focused ultrasound thermal therapy (FUS). A one-dimensional (1D) MR elastography (MRE) pulse sequence was evaluated for the purpose of obtaining rapid measurements of thermally induced changes in tissue stiffness and temperature for monitoring FUS treatments. The accuracy of the 1D measurement was studied by comparing tissue displacements measured by 1D MRE with those measured by the well-established 2D MRE pulse sequence. The reproducibility of the 1D MRE measurement was assessed, in gel phantoms and ex vivo porcine tissue, for varied FUS intensity levels (31.5-199.9 W cm -2 ) and over a range of displacements at the focus (0.1-1 μm). Temperature elevations in agarose gel phantoms were measured using 1D MRE and calibrated using fiberoptic-thermometer-based measurements. The 1D MRE displacement measurements are highly correlated with those obtained with the 2D technique (R 2 = 0.88-0.93), indicating that 1D MRE can successfully measure tissue displacement. Ten repeated trials at each FUS power level yielded a minimum detectable displacement change of 0.2 μm in phantoms and 0.4 μm in tissue (at 95% confidence level). The 1D MRE temperature measurements correlated well with temperature changes measured simultaneously with fiberoptic thermometers (R 2 = 0.97). The 1D MRE technique is capable of detecting tissue displacements as low as 0.4 μm, which is an order of magnitude smaller than 5 μm displacements expected during FUS therapy (Le et al 2005 AIP Conf. Proc.: Ther. Ultrasound 829 186-90). Additionally, 1D MRE was shown to provide adequate measurements of temperature elevations in tissue. These findings indicate that 1D MRE may be an effective tool for monitoring FUS treatments

Mesh three-dimensional arm orthosis with built-in ultrasound physiotherapy system

Science.gov (United States)

Kashapova, R. M.; Kashapov, R. N.; Kashapova, R. S.

2017-09-01

The possibility of using the built-in ultrasound physiotherapy system of the hand orthosis is explored in the work. The individual mesh orthosis from nylon 12 was manufactured by the 3D prototyping method on the installation of selective laser sintering SLS SPro 60HD. The applied technology of three-dimensional scanning made it possible to obtain a model of the patient’s hand and on the basis of it to build a virtual model of the mesh frame. In the course of the research, the developed system of ultrasound exposure was installed on the orthosis and its tests were carried out. As a result, the acceleration of the healing process and the reduction in the time of wearing orthosis were found.

Two-dimensional effects in nonlinear Kronig-Penney models

DEFF Research Database (Denmark)

Gaididei, Yuri Borisovich; Christiansen, Peter Leth; Rasmussen, Kim

1997-01-01

An analysis of two-dimensional (2D) effects in the nonlinear Kronig-Penney model is presented. We establish an effective one-dimensional description of the 2D effects, resulting in a set of pseudodifferential equations. The stationary states of the 2D system and their stability is studied...

3D ultrasound imaging : Fast and cost-effective morphometry of musculoskeletal tissue

NARCIS (Netherlands)

Weide, Guido; Van Der Zwaard, Stephan; Huijing, Peter A.; Jaspers, Richard T.; Harlaar, Jaap

2017-01-01

The developmental goal of 3D ultrasound imaging (3DUS) is to engineer a modality to perform 3D morphological ultrasound analysis of human muscles. 3DUS images are constructed from calibrated freehand 2D B-mode ultrasound images, which are positioned into a voxel array. Ultrasound (US) imaging allows

Piezoelectricity in Two-Dimensional Materials

KAUST Repository

Wu, Tao

2015-02-25

Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity - the conversion of mechanical stress into electricity - in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards embedding low-dimensional materials into future disruptive technologies. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Strain measurement of abdominal aortic aneurysm with real-time 3D ultrasound speckle tracking.

Science.gov (United States)

Bihari, P; Shelke, A; Nwe, T H; Mularczyk, M; Nelson, K; Schmandra, T; Knez, P; Schmitz-Rixen, T

2013-04-01

Abdominal aortic aneurysm rupture is caused by mechanical vascular tissue failure. Although mechanical properties within the aneurysm vary, currently available ultrasound methods assess only one cross-sectional segment of the aorta. This study aims to establish real-time 3-dimensional (3D) speckle tracking ultrasound to explore local displacement and strain parameters of the whole abdominal aortic aneurysm. Validation was performed on a silicone aneurysm model, perfused in a pulsatile artificial circulatory system. Wall motion of the silicone model was measured simultaneously with a commercial real-time 3D speckle tracking ultrasound system and either with laser-scan micrometry or with video photogrammetry. After validation, 3D ultrasound data were collected from abdominal aortic aneurysms of five patients and displacement and strain parameters were analysed. Displacement parameters measured in vitro by 3D ultrasound and laser scan micrometer or video analysis were significantly correlated at pulse pressures between 40 and 80 mmHg. Strong local differences in displacement and strain were identified within the aortic aneurysms of patients. Local wall strain of the whole abdominal aortic aneurysm can be analysed in vivo with real-time 3D ultrasound speckle tracking imaging, offering the prospect of individual non-invasive rupture risk analysis of abdominal aortic aneurysms. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Novel two-dimensional uranyl-organic assemblages in the citrate and D(-)-citramalate families

International Nuclear Information System (INIS)

Thuery, P.

2008-01-01

Uranyl nitrate reacts with D(-)-citramalic acid (H(3)citml) under mild hydrothermal conditions to give the two-dimensional polymer [UO 2 (Hcitml)] 1, in which each ligand chelates one metal atom through its hydroxyl and alpha- carboxylate groups and binds to three others in monodentate fashion. The resulting neutral layers display isolated uranyl pentagonal bipyramidal polyhedra. Whereas citric acid (H(4)cit) has been shown previously to give various three- and mono-dimensional uranyl organic assemblages, complexation under hydrothermal conditions in the presence of either NaOH/NEt 4 Cl or pyridine yields the complexes [NEt 4 ] 2 [(UO 2 ) 3 (cit) 2 (H 2 O) 2 ]· 2H 2 O 2 and [Hpy] 2 )[(UO 2 ) 3 (cit)(Hcit)(OH)] 3, respectively, which both crystallize as two- dimensional frameworks. The layers are either planar and separated by the counter ions in 2 or corrugated and hydrogen bonded to one another in 3. In both 2 and 3, [UO 2 (cit)] 2 4- dimeric subunits with edge-sharing pentagonal bipyramidal uranium coordination polyhedra are present but, in both cases and in contrast with previous structures containing [UO 2 (Hcit)] 2 2- dimers, the carboxylate group not involved in the dimer formation is coordinated to another uranyl unit, which is part of either a centrosymmetric hexagonal bipyramidal bis-aquated group or a different, [(UO 2 ) 2 (Hcit)(OH)] dimer. These examples of two- dimensional assemblages further illustrate the variety of architectures which can be obtained with citric and related acids and the important structure-directing effects of the counter ions. (author)

General Ultrasound Imaging

Medline Plus

Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... legs, neck and/or brain (in infants and children) or within various body organs such as the ...

General Ultrasound Imaging

Medline Plus

Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... color picture. It can also convert blood flow information into a distinctive sound that can be heard ...

General Ultrasound Imaging

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Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... care physician, or to the physician or other healthcare provider who requested the exam. Usually, the referring ...

General Ultrasound Imaging

Medline Plus

Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... possible charges you will incur. Web page review process: This Web page is reviewed regularly by a ...

General Ultrasound Imaging

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Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... sonography is performed using the same transducer. Rarely, young children may need to be sedated in order ...

General Ultrasound Imaging

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Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... American College of Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise ...

General Ultrasound Imaging

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Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 ...

Prenatal 3D Ultrasound Diagnostics in Cleidocranial Dysplasia

DEFF Research Database (Denmark)

Hermann, NV; Hove, HD; Jørgensen, C

2009-01-01

A 34-year-old Caucasian woman with cleidocranial dysplasia (CCD) and a known family history of CCD was referred for an ultrasound examination in the first trimester of her second pregnancy. Molecular genetic analysis of the RUNX2 gene was non-informative. A routine 2D ultrasound examination carried...

Ultrasound

Science.gov (United States)

Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's ...

Thermoelastic expansion vs. piezoelectricity for high-frequency, 2-D arrays.

Science.gov (United States)

Buma, Takashi; Spisar, Monica; O'Donnell, Matthew

2003-08-01

Optical generation using the thermoelastic effect has traditionally suffered from low conversion efficiency. We previously demonstrated increased efficiency of nearly 20 dB with an optical absorbing layer consisting of a mixture of polydimethylsiloxane (PDMS) and carbon black spin coated onto a glass microscope slide. In this paper we show that the radiated power from a black PDMS film is comparable to a 20 MHz piezoelectric two-dimensional (2-D) array element. Furthermore, we predict that a thermoelastic array element can produce similar acoustic power levels compared to ideal piezoelectric 2-D array elements at frequencies in the 100 MHz regime. We believe these results show that thermoelastic generation of ultrasound is a promising alternative to piezoelectricity for high-frequency, 2-D arrays.

Simulation Study of Real Time 3-D Synthetic Aperture Sequential Beamforming for Ultrasound Imaging

DEFF Research Database (Denmark)

Hemmsen, Martin Christian; Rasmussen, Morten Fischer; Stuart, Matthias Bo

2014-01-01

in the main system. The real-time imaging capability is achieved using a synthetic aperture beamforming technique, utilizing the transmit events to generate a set of virtual elements that in combination can generate an image. The two core capabilities in combination is named Synthetic Aperture Sequential......This paper presents a new beamforming method for real-time three-dimensional (3-D) ultrasound imaging using a 2-D matrix transducer. To obtain images with sufficient resolution and contrast, several thousand elements are needed. The proposed method reduces the required channel count from...... Beamforming (SASB). Simulations are performed to evaluate the image quality of the presented method in comparison to Parallel beamforming utilizing 16 receive beamformers. As indicators for image quality the detail resolution and Cystic resolution are determined for a set of scatterers at a depth of 90mm...

Ultrasound assessment of fascial connectivity in the lower limb during maximal cervical flexion: technical aspects and practical application of automatic tracking

OpenAIRE

Cruz-Montecinos, Carlos; Cerda, Mauricio; Sanzana-Cuche, Rodolfo; Mart?n-Mart?n, Jaime; Cuesta-Vargas, Antonio

2016-01-01

Background The fascia provides and transmits forces for connective tissues, thereby regulating human posture and movement. One way to assess the myofascial interaction is a fascia ultrasound recording. Ultrasound can follow fascial displacement either manually or automatically through two-dimensional (2D) method. One possible method is the iterated Lucas-Kanade Pyramid (LKP) algorithm, which is based on automatic pixel tracking during passive movements in 2D fascial displacement assessments. ...

2D array transducers for real-time 3D ultrasound guidance of interventional devices

Science.gov (United States)

Light, Edward D.; Smith, Stephen W.

2009-02-01

We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Associates, Inc. micro-miniature ribbon cables. We have recently constructed a new transducer using a braided wiring technology from Precision Interconnect. This transducer consists of 54 elements at 4.8 MHz with pitch of 0.20 mm and typical -6 dB bandwidth of 22%. In all cases, the transducer and wiring assembly were integrated with an 11 French catheter of a Cook Medical deployment device for vena cava filters. Preliminary in vivo and in vitro testing is ongoing including simultaneous 3D ultrasound and x-ray fluoroscopy.

Functionalization of liquid-exfoliated two-dimensional 2H-MoS2.

Science.gov (United States)

Backes, Claudia; Berner, Nina C; Chen, Xin; Lafargue, Paul; LaPlace, Pierre; Freeley, Mark; Duesberg, Georg S; Coleman, Jonathan N; McDonald, Aidan R

2015-02-23

Layered two-dimensional (2D) inorganic transition-metal dichalchogenides (TMDs) have attracted great interest as a result of their potential application in optoelectronics, catalysis, and medicine. However, methods to functionalize and process such 2D TMDs remain scarce. We have established a facile route towards functionalized layered MoS2 . We found that the reaction of liquid-exfoliated 2D MoS2 , with M(OAc)2 salts (M=Ni, Cu, Zn; OAc=acetate) yielded functionalized MoS2 -M(OAc)2 materials. Importantly, this method furnished the 2H-polytype of MoS2 which is a semiconductor. X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT-IR), and thermogravimetric analysis (TGA) provide strong evidence for the coordination of MoS2 surface sulfur atoms to the M(OAc)2 salt. Interestingly, functionalization of 2H-MoS2 allows for its dispersion/processing in more conventional laboratory solvents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Real-Time 3-Dimensional Ultrasound-Assisted Infraclavicular Brachial Plexus Catheter Placement: Implications of a New Technology

Directory of Open Access Journals (Sweden)

Steven R. Clendenen

2010-01-01

Full Text Available Background. There are a variety of techniques for targeting placement of an infraclavicular blockade; these include eliciting paresthesias, nerve stimulation, and 2-dimensional (2D ultrasound (US guidance. Current 2D US allows direct visualization of a “flat” image of the advancing needle and neurovascular structures but without the ability to extensively analyze multidimensional data and allow for real-time manipulation. Three-dimensional (3D ultrasonography has gained popularity and usefulness in many clinical specialties such as obstetrics and cardiology. We describe some of the potential clinical applications of 3D US in regional anesthesia. Methods. This case represents an infraclavicular catheter placement facilitated by 3D US, which demonstrates 360-degree spatial relationships of the entire anatomic region. Results. The block needle, peripheral nerve catheter, and local anesthetic diffusion were observed in multiple planes of view without manipulation of the US probe. Conclusion. Advantages of 3D US may include the ability to confirm correct needle and catheter placement prior to the injection of local anesthetic. The spread of local anesthetic along the length of the nerve can be easily observed while manipulating the 3D images in real-time by simply rotating the trackball on the US machine to provide additional information that cannot be identified with 2D US alone.

3D power Doppler ultrasound in early diagnosis of preeclampsia.

Science.gov (United States)

Neto, R Moreira; Ramos, J G L

2016-01-01

Preeclampsia is a known cause of maternal, fetal and neonatal morbidity and mortality. Thus, evaluation of the predicting value of comparing 3D power Doppler indices (3DPD) of uteroplacental circulation (UPC) in the first and second trimester in patients who developed preeclampsia (PE) and those who did not and testing the hypothesis that the parameters of vascularization and placenta flow intensity, as determined by three-dimensional ultrasound (3D), are different in normal pregnancies compared with preeclampsia, could be a suitable screening method. A prospective observational study using 3D power Doppler were performed to evaluate the placental perfusion in 96 pregnant women who came to do the ultrasound routine between 11 and 14 weeks. The placental vascular index (VI), flow index (FI), blood vessels and blood flow index (VFI) by three-dimensional Doppler histogram were calculated. All patients repeated the exam between 16 and 20 weeks. The outcome was scored as normal or preeclamptic. Placental vascular indices including VI, FI and VFI were significantly lower in preeclamptic placentas compared with controls in the study performed in the second trimester (ppower Doppler assessment of placental vascular indices in the second trimester has the potential to detect women at risk for subsequent development of PE. Copyright © 2015 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.

Three Dimensional Sheaf of Ultrasound Planes Reconstruction (SOUPR) of Ablated Volumes

Science.gov (United States)

Ingle, Atul; Varghese, Tomy

2014-01-01

This paper presents an algorithm for three dimensional reconstruction of tumor ablations using ultrasound shear wave imaging with electrode vibration elastography. Radiofrequency ultrasound data frames are acquired over imaging planes that form a subset of a sheaf of planes sharing a common axis of intersection. Shear wave velocity is estimated separately on each imaging plane using a piecewise linear function fitting technique with a fast optimization routine. An interpolation algorithm then computes velocity maps on a fine grid over a set of C-planes that are perpendicular to the axis of the sheaf. A full three dimensional rendering of the ablation can then be created from this stack of C-planes; hence the name “Sheaf Of Ultrasound Planes Reconstruction” or SOUPR. The algorithm is evaluated through numerical simulations and also using data acquired from a tissue mimicking phantom. Reconstruction quality is gauged using contrast and contrast-to-noise ratio measurements and changes in quality from using increasing number of planes in the sheaf are quantified. The highest contrast of 5 dB is seen between the stiffest and softest regions of the phantom. Under certain idealizing assumptions on the true shape of the ablation, good reconstruction quality while maintaining fast processing rate can be obtained with as few as 6 imaging planes suggesting that the method is suited for parsimonious data acquisitions with very few sparsely chosen imaging planes. PMID:24808405

Two dimensional solid state NMR

International Nuclear Information System (INIS)

Kentgens, A.P.M.

1987-01-01

This thesis illustrates, by discussing some existing and newly developed 2D solid state experiments, that two-dimensional NMR of solids is a useful and important extension of NMR techniques. Chapter 1 gives an overview of spin interactions and averaging techniques important in solid state NMR. As 2D NMR is already an established technique in solutions, only the basics of two dimensional NMR are presented in chapter 2, with an emphasis on the aspects important for solid spectra. The following chapters discuss the theoretical background and applications of specific 2D solid state experiments. An application of 2D-J resolved NMR, analogous to J-resolved spectroscopy in solutions, to natural rubber is given in chapter 3. In chapter 4 the anisotropic chemical shift is mapped out against the heteronuclear dipolar interaction to obtain information about the orientation of the shielding tensor in poly-(oxymethylene). Chapter 5 concentrates on the study of super-slow molecular motions in polymers using a variant of the 2D exchange experiment developed by us. Finally chapter 6 discusses a new experiment, 2D nutation NMR, which makes it possible to study the quadrupole interaction of half-integer spins. 230 refs.; 48 figs.; 8 tabs

Piezoelectricity in Two-Dimensional Materials

KAUST Repository

Wu, Tao; Zhang, Hua

2015-01-01

Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity - the conversion of mechanical stress into electricity - in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards

Method of solving conformal models in D-dimensional space 2: A family of exactly solvable models in D > 2

International Nuclear Information System (INIS)

Fradkin, E.S.; Palchik, M.Ya.

1996-02-01

We study a family of exactly solvable models of conformally-invariant quantum field theory in D-dimensional space. We demonstrate the existence of D-dimensional analogs of primary and secondary fields. Under the action of energy-momentum tensor and conserved currents, the primary fields creates an infinite set of (tensor) secondary fields of different generations. The commutators of secondary fields with zero components of current and energy-momentum tensor include anomalous operator terms. We show that the Hilbert space of conformal theory has a special sector which structure is solely defined by the Ward identities independently on the choice of dynamical model. The states of this sector are constructed from secondary fields. Definite self-consistent conditions on the states of the latter sector fix the choice of the field model uniquely. In particular, Lagrangian models do belong to this class of models. The above self-consistent conditions are formulated as follows. Special superpositions Q s , s = 1,2,... of secondary fields are constructed. Each superposition is determined by the requirement that the form of its commutators with energy-momentum tensor and current (i.e. transformation properties) should be identical to that of a primary field. Each equation Q s (x) = 0 is consistent, and defines an exactly solvable model for D ≥ 3. The structure of these models are analogous to that of well-known two dimensional conformal models. The states Q s (x) modul 0> are analogous to the null-vectors of two dimensional theory. In each of these models one can obtain a closed set of differential equations for all the higher Green functions, as well as algebraic equations relating the scale dimension of fundamental field to the D-dimensional analog of a central charge. As an example, we present a detailed discussion of a pair of exactly solvable models in even-dimensional space D ≥ 4. (author). 28 refs

Real-time registration of 3D to 2D ultrasound images for image-guided prostate biopsy.

Science.gov (United States)

Gillies, Derek J; Gardi, Lori; De Silva, Tharindu; Zhao, Shuang-Ren; Fenster, Aaron

2017-09-01

During image-guided prostate biopsy, needles are targeted at tissues that are suspicious of cancer to obtain specimen for histological examination. Unfortunately, patient motion causes targeting errors when using an MR-transrectal ultrasound (TRUS) fusion approach to augment the conventional biopsy procedure. This study aims to develop an automatic motion correction algorithm approaching the frame rate of an ultrasound system to be used in fusion-based prostate biopsy systems. Two modes of operation have been investigated for the clinical implementation of the algorithm: motion compensation using a single user initiated correction performed prior to biopsy, and real-time continuous motion compensation performed automatically as a background process. Retrospective 2D and 3D TRUS patient images acquired prior to biopsy gun firing were registered using an intensity-based algorithm utilizing normalized cross-correlation and Powell's method for optimization. 2D and 3D images were downsampled and cropped to estimate the optimal amount of image information that would perform registrations quickly and accurately. The optimal search order during optimization was also analyzed to avoid local optima in the search space. Error in the algorithm was computed using target registration errors (TREs) from manually identified homologous fiducials in a clinical patient dataset. The algorithm was evaluated for real-time performance using the two different modes of clinical implementations by way of user initiated and continuous motion compensation methods on a tissue mimicking prostate phantom. After implementation in a TRUS-guided system with an image downsampling factor of 4, the proposed approach resulted in a mean ± std TRE and computation time of 1.6 ± 0.6 mm and 57 ± 20 ms respectively. The user initiated mode performed registrations with in-plane, out-of-plane, and roll motions computation times of 108 ± 38 ms, 60 ± 23 ms, and 89 ± 27 ms, respectively, and corresponding

Ultrasound assessment of the Essure contraceptive devices: is three-dimensional ultrasound really needed?

Science.gov (United States)

Paladini, Dario; Di Spiezio Sardo, Attilio; Coppola, Carmela; Zizolfi, Brunella; Pastore, Gaetano; Nappi, Carmine

2015-01-01

To evaluate the feasibility of 3-dimensional ultrasound (3DUS) for sonographic localization of Essure microinserts, comparing it with 2-dimensional ultrasound (2DUS) insofar as time to visualize the inserts and accuracy in determining their localization. Prospective study (Canadian Task Force classification II-2). University clinic. Twenty-seven consecutive women undergoing hysteroscopic Essure device placement. Essure microinserts were inserted in the outpatient hysteroscopy clinic following the manufacturer's recommendations, leaving from 3 to 8 loops of the inserts in the uterine cavity. In all patients, 2DUS and 3DUS were performed 3 months after the procedure. 2DUS was performed first; the device(s) were located, and their position was recorded. Then 3DUS scans were acquired, trying when possible to have both devices at least at a 45-degree angle with the insonation beam for optimal rendering on 3DUS. The OmniView method with volume contrast imaging was used to show the relationships of the microinserts within the uterine cavity when possible. To define the position of the Essure device in relation to the uterus and the salpinges, we used the classification developed by Legendre and colleagues. After sonographic evaluation all women underwent hysterosalpingography to assess the success of sterilization. Hysteroscopic insertion was successful in all patients, with 2 Essure devices placed in 25 patients and 1 device in 2 patients (due to previous salpingectomy performed because of ectopic pregnancy), for a total of 52 devices. One spontaneous late (within 3 months) expulsion of the device occurred; the device had migrated almost completely into the uterine cavity. At 3-month follow-up, all 51 correctly placed devices were easily observed at 2DUS (mean [SD] duration of the procedure, 2.25 [0.8] minutes). At 3DUS in 51 cases, the device was in perfect position (1+2+3) in 21 (41.2%), in position 2+3 in 14 (27.4%), and in position +3 in 16 (31.4%). Both microinserts

A high-frequency transimpedance amplifier for CMOS integrated 2D CMUT array towards 3D ultrasound imaging.

Science.gov (United States)

Huang, Xiwei; Cheong, Jia Hao; Cha, Hyouk-Kyu; Yu, Hongbin; Je, Minkyu; Yu, Hao

2013-01-01

One transimpedance amplifier based CMOS analog front-end (AFE) receiver is integrated with capacitive micromachined ultrasound transducers (CMUTs) towards high frequency 3D ultrasound imaging. Considering device specifications from CMUTs, the TIA is designed to amplify received signals from 17.5MHz to 52.5MHz with center frequency at 35MHz; and is fabricated in Global Foundry 0.18-µm 30-V high-voltage (HV) Bipolar/CMOS/DMOS (BCD) process. The measurement results show that the TIA with power-supply 6V can reach transimpedance gain of 61dBΩ and operating frequency from 17.5MHz to 100MHz. The measured input referred noise is 27.5pA/√Hz. Acoustic pulse-echo testing is conducted to demonstrate the receiving functionality of the designed 3D ultrasound imaging system.

Two-and three-dimensional CT reconstruction

International Nuclear Information System (INIS)

Fishman, E.K.; Ney, D.R.; Magid, D.

1990-01-01

This paper determines the optimal imaging sequence for creating two- and three-dimensional (2D/3D) skeletal reconstructions from CT data. A cadaver femur, a bone phantom, and a surgically created fracture were scanned with varying protocols to determine the optimal protocol for creating 2D/3D images. The scanning protocols used varying section thickness (2, 4, and 8 mm) as well as scan spacing (2, 3, 4 and 8 mm). All images were reconstructed into 2D data sets with a bicubic interpolation and 3D datasets with volumetric rendering. The results were reviewed by two reviewers to determine the quality of images reconstruction

Experimental study of sector and linear array ultrasound accuracy and the influence of navigated 3D-reconstruction as compared to MRI in a brain tumor model.

Science.gov (United States)

Siekmann, Max; Lothes, Thomas; König, Ralph; Wirtz, Christian Rainer; Coburger, Jan

2018-03-01

Currently, intraoperative ultrasound in brain tumor surgery is a rapidly propagating option in imaging technology. We examined the accuracy and resolution limits of different ultrasound probes and the influence of 3D-reconstruction in a phantom and compared these results to MRI in an intraoperative setting (iMRI). An agarose gel phantom with predefined gel targets was examined with iMRI, a sector (SUS) and a linear (LUS) array probe with two-dimensional images. Additionally, 3D-reconstructed sweeps in perpendicular directions were made of every target with both probes, resulting in 392 measurements. Statistical calculations were performed, and comparative boxplots were generated. Every measurement of iMRI and LUS was more precise than SUS, while there was no apparent difference in height of iMRI and 3D-reconstructed LUS. Measurements with 3D-reconstructed LUS were always more accurate than in 2D-LUS, while 3D-reconstruction of SUS showed nearly no differences to 2D-SUS in some measurements. We found correlations of 3D-reconstructed SUS and LUS length and width measurements with 2D results in the same image orientation. LUS provides an accuracy and resolution comparable to iMRI, while SUS is less exact than LUS and iMRI. 3D-reconstruction showed the potential to distinctly improve accuracy and resolution of ultrasound images, although there is a strong correlation with the sweep direction during data acquisition.

Real-time interpolation for true 3-dimensional ultrasound image volumes.

Science.gov (United States)

Ji, Songbai; Roberts, David W; Hartov, Alex; Paulsen, Keith D

2011-02-01

We compared trilinear interpolation to voxel nearest neighbor and distance-weighted algorithms for fast and accurate processing of true 3-dimensional ultrasound (3DUS) image volumes. In this study, the computational efficiency and interpolation accuracy of the 3 methods were compared on the basis of a simulated 3DUS image volume, 34 clinical 3DUS image volumes from 5 patients, and 2 experimental phantom image volumes. We show that trilinear interpolation improves interpolation accuracy over both the voxel nearest neighbor and distance-weighted algorithms yet achieves real-time computational performance that is comparable to the voxel nearest neighbor algrorithm (1-2 orders of magnitude faster than the distance-weighted algorithm) as well as the fastest pixel-based algorithms for processing tracked 2-dimensional ultrasound images (0.035 seconds per 2-dimesional cross-sectional image [76,800 pixels interpolated, or 0.46 ms/1000 pixels] and 1.05 seconds per full volume with a 1-mm(3) voxel size [4.6 million voxels interpolated, or 0.23 ms/1000 voxels]). On the basis of these results, trilinear interpolation is recommended as a fast and accurate interpolation method for rectilinear sampling of 3DUS image acquisitions, which is required to facilitate subsequent processing and display during operating room procedures such as image-guided neurosurgery.

An experimental study: quantitatively evaluating the change of the content of collagen fibres in penis with two-dimensional ShearWave™ Elastography.

Science.gov (United States)

Qiao, X-H; Zhang, J-J; Gao, F; Li, F; Bai, M; Du, L-F; Xing, J-F

2017-06-01

The purpose of this study was to explore the value of two-dimensional ShearWave ™ Elastography (2D-SWE) on quantitatively evaluating the change of the content of collagen fibres in penis. Twenty male Sprague Dawley rats were divided into the pre-sexual maturity group (Group 1) and the sexual decline group (Group 2) according to age. The ultrafast ultrasound device Aixplorer ® (SuperSonic Imagine, Aix-en-Provence, France) was used for 2D-SWE imaging of penis, and the measurement index was shear wave stiffness (SWS). The immunohistochemistry was used to analyse the content of collagen fibres in penis, and the measurement index was positive area percentage (PAP). The differences of SWS between the two groups and PAP between the two groups were analysed. SWS of Group 1 and Group 2 was 10.18 ± 1.09 and 8.02 ± 1.34 kPa, and SWS of Group 2 was significantly lower than Group 1 (p penis measured with 2D-SWE would change significantly as well. Two-dimensional SWE can be used to quantitatively evaluate the change of the content of collagen fibres in penis. © 2016 Blackwell Verlag GmbH.

Design of a rotational three-dimensional nonimaging device by a compensated two-dimensional design process.

Science.gov (United States)

Yang, Yi; Qian, Ke-Yuan; Luo, Yi

2006-07-20

A compensation process has been developed to design rotational three-dimensional (3D) nonimaging devices. By compensating the desired light distribution during a two-dimensional (2D) design process for an extended Lambertian source using a compensation coefficient, the meridian plane of a 3D device with good performance can be obtained. This method is suitable in many cases with fast calculation speed. Solutions to two kinds of optical design problems have been proposed, and the limitation of this compensated 2D design method is discussed.

3D ultrasound Nakagami imaging for radiation-induced vaginal fibrosis

Science.gov (United States)

Yang, Xiaofeng; Rossi, Peter; Shelton, Joseph; Bruner, Debrorah; Tridandapani, Srini; Liu, Tian

2014-03-01

Radiation-induced vaginal fibrosis is a debilitating side-effect affecting up to 80% of women receiving radiotherapy for their gynecological (GYN) malignancies. Despite the significant incidence and severity, little research has been conducted to identify the pathophysiologic changes of vaginal toxicity. In a previous study, we have demonstrated that ultrasound Nakagami shape and PDF parameters can be used to quantify radiation-induced vaginal toxicity. These Nakagami parameters are derived from the statistics of ultrasound backscattered signals to capture the physical properties (e.g., arrangement and distribution) of the biological tissues. In this paper, we propose to expand this Nakagami imaging concept from 2D to 3D to fully characterize radiation-induced changes to the vaginal wall within the radiation treatment field. A pilot study with 5 post-radiotherapy GYN patients was conducted using a clinical ultrasound scanner (6 MHz) with a mechanical stepper. A serial of 2D ultrasound images, with radio-frequency (RF) signals, were acquired at 1 mm step size. The 2D Nakagami shape and PDF parameters were calculated from the RF signal envelope with a sliding window, and then 3D Nakagami parameter images were generated from the parallel 2D images. This imaging method may be useful as we try to monitor radiation-induced vaginal injury, and address vaginal toxicities and sexual dysfunction in women after radiotherapy for GYN malignancies.

Velocity Estimation in Medical Ultrasound [Life Sciences

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt; Villagómez Hoyos, Carlos Armando; Holbek, Simon

2017-01-01

This article describes the application of signal processing in medical ultrasound velocity estimation. Special emphasis is on the relation among acquisition methods, signal processing, and estimators employed. The description spans from current clinical systems for one-and two-dimensional (1-D an...

Evaluation of a three-dimensional ultrasound localisation system incorporating probe pressure correction for use in partial breast irradiation.

Science.gov (United States)

Harris, E J; Symonds-Taylor, R; Treece, G M; Gee, A H; Prager, R W; Brabants, P; Evans, P M

2009-10-01

This work evaluates a three-dimensional (3D) freehand ultrasound-based localisation system with new probe pressure correction for use in partial breast irradiation. Accuracy and precision of absolute position measurement was measured as a function of imaging depth (ID), object depth, scanning direction and time using a water phantom containing crossed wires. To quantify the improvement in accuracy due to pressure correction, 3D scans of a breast phantom containing ball bearings were obtained with and without pressure. Ball bearing displacements were then measured with and without pressure correction. Using a single scan direction (for all imaging depths), the mean error was <1.3 mm, with the exception of the wires at 68.5 mm imaged with an ID of 85 mm, which gave a mean error of -2.3 mm. Precision was greater than 1 mm for any single scan direction. For multiple scan directions, precision was within 1.7 mm. Probe pressure corrections of between 0 mm and 2.2 mm have been observed for pressure displacements of 1.1 mm to 4.2 mm. Overall, anteroposterior position measurement accuracy increased from 2.2 mm to 1.6 mm and to 1.4 mm for the two opposing scanning directions. Precision is comparable to that reported for other commercially available ultrasound localisation systems, provided that 3D image acquisition is performed in the same scan direction. The existing temporal calibration is imperfect and a "per installation" calibration would further improve the accuracy and precision. Probe pressure correction was shown to improve the accuracy and will be useful for the localisation of the excision cavity in partial breast radiotherapy.

Dynamic three-dimensional display of common congenital cardiac defects from reconstruction of two-dimensional echocardiographic images.

Science.gov (United States)

Hsieh, K S; Lin, C C; Liu, W S; Chen, F L

1996-01-01

Two-dimensional echocardiography had long been a standard diagnostic modality for congenital heart disease. Further attempts of three-dimensional reconstruction using two-dimensional echocardiographic images to visualize stereotypic structure of cardiac lesions have been successful only recently. So far only very few studies have been done to display three-dimensional anatomy of the heart through two-dimensional image acquisition because such complex procedures were involved. This study introduced a recently developed image acquisition and processing system for dynamic three-dimensional visualization of various congenital cardiac lesions. From December 1994 to April 1995, 35 cases were selected in the Echo Laboratory here from about 3000 Echo examinations completed. Each image was acquired on-line with specially designed high resolution image grazmber with EKG and respiratory gating technique. Off-line image processing using a window-architectured interactive software package includes construction of 2-D ehcocardiographic pixel to 3-D "voxel" with conversion of orthogonal to rotatory axial system, interpolation, extraction of region of interest, segmentation, shading and, finally, 3D rendering. Three-dimensional anatomy of various congenital cardiac defects was shown, including four cases with ventricular septal defects, two cases with atrial septal defects, and two cases with aortic stenosis. Dynamic reconstruction of a "beating heart" is recorded as vedio tape with video interface. The potential application of 3D display of the reconstruction from 2D echocardiographic images for the diagnosis of various congenital heart defects has been shown. The 3D display was able to improve the diagnostic ability of echocardiography, and clear-cut display of the various congenital cardiac defects and vavular stenosis could be demonstrated. Reinforcement of current techniques will expand future application of 3D display of conventional 2D images.

Two-dimensional x-ray diffraction

CERN Document Server

He, Bob B

2009-01-01

Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

Two-dimensional MoS2: A promising building block for biosensors.

Science.gov (United States)

Gan, Xiaorong; Zhao, Huimin; Quan, Xie

2017-03-15

Recently, two-dimensional (2D) layered nanomaterials have trigged intensive interest due to the intriguing physicochemical properties that stem from a quantum size effect connected with their ultra-thin structure. In particular, 2D molybdenum disulfide (MoS 2 ), as an emerging class of stable inorganic graphene analogs with intrinsic finite bandgap, would possibly complement or even surpass graphene in electronics and optoelectronics fields. In this review, we first discuss the historical development of ultrathin 2D nanomaterials. Then, we are concerned with 2D MoS 2 including its structure-property relationships, synthesis methods, characterization for the layer thickness, and biosensor applications over the past five years. Thereinto, we are highlighting recent advances in 2D MoS 2 -based biosensors, especially emphasize the preparation of sensing elements, roles of 2D MoS 2 , and assay strategies. Finally, on the basis of the current achievements on 2D MoS 2 and other ultrathin layered nanomaterials, perspectives on the challenges and opportunities for the exploration of 2D MoS 2 -based biosensors are put forward. Copyright © 2016 Elsevier B.V. All rights reserved.

Relationship between Plasma D-Dimer Concentration and Three-Dimensional Ultrasound Placental Volume in Women at Risk for Placental Vascular Diseases: A Monocentric Prospective Study.

Directory of Open Access Journals (Sweden)

Cécile Fanget

Full Text Available The aim of this study was to correlate placental volumes deduced from three-dimensional ultrasound and virtual organ computer-aided analysis (VOCAL software with systemic concentrations of D-dimer and soluble endothelial protein C receptor (sEPCR.This was a monocentric experimental prospective study conducted from October 2008 to July 2009. Forty consecutive patients at risk of placental vascular pathology (PVP recurrence or occurrence were included. Placental volumes were systematically measured three times (11-14, 16-18 and 20-22 weeks of gestation (WG by two independent sonographers. D-dimers and sEPCR plasma concentrations were measured using ELISA kits (Enzyme Linked ImmunoSorbent Assay.Eleven patients had a PVP. The plasma D-dimer level was positively correlated with placental volume (r = 0.45, p < 0.001. A smaller placental volume and placental quotient was evidenced in women who developed a PVP at the three gestational ages, and the difference was more pronounced during the third exam (20 WG. No obvious correlation could be demonstrated between the development of a PVP and the levels of D-dimer and sEPCR. There was no significant difference in the values of placental volumes measured by the two sonographers.The placenta growth could be a major determinant of the elevation of D-dimer during pregnancy. Consideration of placental volume could allow for modulation of the D-dimer concentrations for restoring their clinical interest.

Peak clustering in two-dimensional gas chromatography with mass spectrometric detection based on theoretical calculation of two-dimensional peak shapes: the 2DAid approach.

Science.gov (United States)

van Stee, Leo L P; Brinkman, Udo A Th

2011-10-28

A method is presented to facilitate the non-target analysis of data obtained in temperature-programmed comprehensive two-dimensional (2D) gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-ToF-MS). One main difficulty of GC×GC data analysis is that each peak is usually modulated several times and therefore appears as a series of peaks (or peaklets) in the one-dimensionally recorded data. The proposed method, 2DAid, uses basic chromatographic laws to calculate the theoretical shape of a 2D peak (a cluster of peaklets originating from the same analyte) in order to define the area in which the peaklets of each individual compound can be expected to show up. Based on analyte-identity information obtained by means of mass spectral library searching, the individual peaklets are then combined into a single 2D peak. The method is applied, amongst others, to a complex mixture containing 362 analytes. It is demonstrated that the 2D peak shapes can be accurately predicted and that clustering and further processing can reduce the final peak list to a manageable size. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultrasound-based guidance of intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Fung, Albert Y.C.; Ayyangar, Komanduri M.; Djajaputra, David; Nehru, Ramasamy M.; Enke, Charles A.

2006-01-01

In ultrasound-guided intensity-modulated radiation therapy (IMRT) of prostate cancer, ultrasound imaging ascertains the anatomical position of patients during x-ray therapy delivery. The ultrasound transducers are made of piezoelectric ceramics. The same crystal is used for both ultrasound production and reception. Three-dimensional (3D) ultrasound devices capture and correlate series of 2-dimensional (2D) B-mode images. The transducers are often arranged in a convex array for focusing. Lower frequency reaches greater depth, but results in low resolution. For clear image, some gel is usually applied between the probe and the skin contact surface. For prostate positioning, axial and sagittal scans are performed, and the volume contours from computed tomography (CT) planning are superimposed on the ultrasound images obtained before radiation delivery at the linear accelerator. The planning volumes are then overlaid on the ultrasound images and adjusted until they match. The computer automatically deduces the offset necessary to move the patient so that the treatment area is in the correct location. The couch is translated as needed. The currently available commercial equipment can attain a positional accuracy of 1-2 mm. Commercial manufacturer designs differ in the detection of probe coordinates relative to the isocenter. Some use a position-sensing robotic arm, while others have infrared light-emitting diodes or pattern-recognition software with charge-couple-device cameras. Commissioning includes testing of image quality and positional accuracy. Ultrasound is mainly used in prostate positioning. Data for 7825 daily fractions of 234 prostate patients indicated average 3D inter-fractional displacement of about 7.8 mm. There was no perceivable trend of shift over time. Scatter plots showed slight prevalence toward superior-posterior directions. Uncertainties of ultrasound guidance included tissue inhomogeneities, speckle noise, probe pressure, and inter

Three-dimensional ultrasonography in the diagnosis of deep endometriosis.

Science.gov (United States)

Guerriero, Stefano; Saba, Luca; Ajossa, Silvia; Peddes, Cristina; Angiolucci, Marco; Perniciano, Maura; Melis, Gian Benedetto; Alcázar, Juan Luis

2014-06-01

In the use of 'tenderness-guided' transvaginal ultrasound, is the diagnostic accuracy of three-dimensional (3D) ultrasonography better than two-dimensional (2D) ultrasonography in the identification of deep endometriosis? Three-dimensional ultrasonography has a significantly higher diagnostic accuracy in the diagnosis of posterior locations of deep endometriosis without intestinal involvement, such as the uterosacral ligaments, vaginal and rectovaginal endometriosis. The only previous study of the diagnosis of posterior compartment endometriosis reported an poor sensitivity of 3D ultrasonography for uterosacral and sigmoid colon involvement. This diagnostic test study included 202 patients scheduled for surgery because of clinical suspicion of deep pelvic endometriosis and was carried out between January 2009 and September 2012. Modified transvaginal ultrasonography was performed on all of the women by a single examiner. Two locations of deep endometriosis were considered: intestinal involvement and other posterior lesions (including vaginal location, rectovaginal septum and uterosacral ligaments). Once the 2D ultrasonography had been performed, the 3D acquisition was performed and the obtained volume was stored. To avoid the risk of recall bias, the same operator evaluated the 3D volumes 6 months after the last examination using virtual navigation to provide a presumptive diagnosis of the presence and localization of deep endometriosis. In addition, to evaluate the reproducibility of 3D, two operators with different levels of expertise performed a retrospective review of 3D volumes from a random sample of 35 patients, twice, 1 week apart to also assess intraobserver agreement. The diagnostic performance of both tests was expressed as area under the receiver-operating characteristics curve (AUC), sensitivity, specificity, positive and negative predictive values, positive (LR+) and negative (LR-) likelihood ratios, with their respective 95% confidence interval (CI

Multi-dimensional spectrum analysis for 2-D vector velocity estimation

DEFF Research Database (Denmark)

Oddershede, Niels; Løvstakken, Lasse; Torp, Hans

2007-01-01

Fourier space, which is found through the 3-D Fourier transform of the data matrix, and that the plane is tilted according to the axial and lateral velocity components. Two estimators are derived for finding the plane in the 3-D Fourier space, where the integrated power spectrum is largest. The first uses...... the 3-D Fourier transform to find the power spectrum, while the second uses a minimum variance approach. Based on this plane, the axial and lateral velocity components are estimated. A number of phantom How measurements, for flow-to-beam angles of 60, 75, and 90 degrees, were performed to test...... the estimator. The data were collected using our RASMUS experimental ultrasound scanner and a 128 element commercial linear array transducer. The receive apodization function was manipulated, creating an oscillation in the lateral direction, and multiple parallel lines were beamformed simultaneously. The two...

Realistic Vendor-Specific Synthetic Ultrasound Data for Quality Assurance of 2-D Speckle Tracking Echocardiography: Simulation Pipeline and Open Access Database.

Science.gov (United States)

Alessandrini, Martino; Chakraborty, Bidisha; Heyde, Brecht; Bernard, Olivier; De Craene, Mathieu; Sermesant, Maxime; D'Hooge, Jan

2018-03-01

Two-dimensional (2-D) echocardiography is the modality of choice in the clinic for the diagnosis of cardiac disease. Hereto, speckle tracking (ST) packages complement visual assessment by the cardiologist by providing quantitative diagnostic markers of global and regional cardiac function (e.g., displacement, strain, and strain-rate). Yet, the reported high vendor-dependence between the outputs of different ST packages raises clinical concern and hampers the widespread dissemination of the ST technology. In part, this is due to the lack of a solid commonly accepted quality assurance pipeline for ST packages. Recently, we have developed a framework to benchmark ST algorithms for 3-D echocardiography by using realistic simulated volumetric echocardiographic recordings. Yet, 3-D echocardiography remains an emerging technology, whereas the compelling clinical concern is, so far, directed to the standardization of 2-D ST only. Therefore, by building upon our previous work, we present in this paper a pipeline to generate realistic synthetic sequences for 2-D ST algorithms. Hereto, the synthetic cardiac motion is obtained from a complex electromechanical heart model, whereas realistic vendor-specific texture is obtained by sampling a real clinical ultrasound recording. By modifying the parameters in our pipeline, we generated an open-access library of 105 synthetic sequences encompassing: 1) healthy and ischemic motion patterns; 2) the most common apical probe orientations; and 3) vendor-specific image quality from seven different systems. Ground truth deformation is also provided to allow performance analysis. The application of the provided data set is also demonstrated in the benchmarking of a recent academic ST algorithm.

Intra- and interobserver variability of thyroid volume measurements in healthy adults by 2D versus 3D ultrasound

International Nuclear Information System (INIS)

Andermann, P.; Schloegl, S.; Maeder, U.; Luster, M.; Lassmann, M.; Reiners, C.

2007-01-01

Thyroid volume measurement by ultrasonography (US) is essential in numerous clinical diagnostic and therapeutic fields. While known to be limited, the accuracy and precision of two-dimensional (2D) US thyroid volume measurement have not been thoroughly characterized. Objective: We sought to assess the intra- and interobserver variability, accuracy and precision of thyroid volume determination by conventional 2D US in healthy adults using reference volumes determined by three-dimensional (3D) US. Design, methods: In a prospective blinded trial, thyroid volumes of ten volunteers were determined repeatedly by nine experienced sonographers using conventional 2D US (ellipsoid model). The values obtained were statistically compared to the so-called true volumes determined by 3D US (multiplanar approximation), the so-called gold standard, to estimate systematic errors and relative deviations of individual observers. Results: The standard error of measurement (SEM) for one observer and successive measurements (intraobserver variability), was 14%, and for different observers and repeated measurements (interobserver variability), 17%. The minimum relative thyroid volume change significantly different at the 95% level was 39% for the same observer and 46% for different observers. Regarding accuracy, the mean value of the differences showed a significant thyroid volume overestimation (17%, p <0.01) by 2D relative to 3D US. Conclusion: 2D US is appropriate for routine thyroid volumetry. Nevertheless, the so-called human factor (random error) should be kept in mind and correction is needed for methodical bias (systematic error). Further efforts are required to improve the accuracy and precision of 2D US thyroid volumetry by optimizing the underlying geometrical modeling or by the application of 3D US. (orig.)

Learning 2-Dimensional and 3-Dimensional Geometry with Geogebra: Which Would Students Do Better?

Directory of Open Access Journals (Sweden)

Zaleha Ismail

2017-08-01

Full Text Available The purpose of this study is to examine the geometric thinking of young children who worked with GeoGebra to learn two-dimensional (2-D and three-dimensional (3-D geometry. GeoGebra is an open sourced dynamic mathematics software which is applicable for learning mathematics from primary school to secondary school and to higher education. Thirty pupils studying in second grade (Year 2 at a school located in Pontian, a district in one of the Malaysian state participated in the study. They attended GeoGebra sessions to construct and analyze dynamics of two-dimensional and three-dimensional geometry after learning these topics in the conventional setting. Pretest and posttest on two-dimensional and three-dimensional spatial ability based on Van Hiele level of geometric thinking were administered to the pupils. The comparison between pretest and posttest results demonstrate significant enhancement in visualization and informal deduction for both 2-D and 3-D geometry. Moreover from the intervention, the students benefit most in analyzing 3-D and visualizing 2-D geometry. Interestingly, skills and knowledge acquired through activities using GeoGebra in student-centered learning environment could be successfully transferred to paper and pencil test.

Impurity states in two - and three-dimensional disordered systems

International Nuclear Information System (INIS)

Silva, A.F. da; Fabbri, M.

1984-01-01

We investigate the microscopic structure of the impurity states in two-and three-dimensional (2D and 3d) disordered systems. A cluster model is outlined for the donor impurity density of states (DIDS) of doped semiconductors. It is shown that the impurity states are very sensitive to a change in the dimensionality of the system, i.e from 3D to 2D system. It is found that all eigenstates become localized in 2D disordered system for a large range of concentration. (Author) [pt

Impurity states in two-and three-dimensional disordered systems

International Nuclear Information System (INIS)

Silva, A.F. da; Fabbri, M.

1984-04-01

The microscopic structure of the impurity states in two-and three-dimensional (2D and 3D) disordered systems is investigated. A cluster model is outlined for the donor impurity density of states (DIDS) of doped semiconductors. It is shown that the impurity states are very sensitive to a change in the dimensionality of the system, i.e., from 3D to 2D system. It is found that all eigenstates become localized in 2D disordered system for a large range of concentration. (Author) [pt

Solution of the two-dimensional spectral factorization problem

Science.gov (United States)

Lawton, W. M.

1985-01-01

An approximation theorem is proven which solves a classic problem in two-dimensional (2-D) filter theory. The theorem shows that any continuous two-dimensional spectrum can be uniformly approximated by the squared modulus of a recursively stable finite trigonometric polynomial supported on a nonsymmetric half-plane.

Surface Reconstruction-Induced Coincidence Lattice Formation Between Two-Dimensionally Bonded Materials and a Three-Dimensionally Bonded Substrate

NARCIS (Netherlands)

Boschker, Jos E.; Momand, Jamo; Bragaglia, Valeria; Wang, Ruining; Perumal, Karthick; Giussani, Alessandro; Kooi, Bart J.; Riechert, Henning; Calarco, Raffaella

Sb2Te3 films are used for studying the epitaxial registry between two-dimensionally bonded (2D) materials and three-dimensional bonded (3D) substrates. In contrast to the growth of 3D materials, it is found that the formation of coincidence lattices between Sb2Te3 and Si(111) depends on the geometry

THREE-DIMENSIONAL ULTRASOUND AND STENOSIS OF INTERNAL CAROTID ARTERY

Directory of Open Access Journals (Sweden)

Vojko Flis

2003-12-01

Full Text Available Background. Elucidation of the ultrasound structure of the atherosclerotic plaque in stenosis of internal carotid artery may have important implications for carotid surgery. This study compares the ability of computer derived 3D ultrasound gray scale volumetric measurements to diferentiate between ultrasonic structure of symptomatic and asymptomatic carotid plaque causing more than 70% stenosis.Methods. Eightysix internal carotid artery stenoses (70–99%, 45 symptomatic, 41 asymptomatic were imaged with 3D ultrasound to obtain the whole volume of the atherosclerotic plaque. Digitalized sonograms were computerized and normalized to the gray scale median (GSM of blood (0 and vessel adventitia (200. Plaque GSM was obtained for the whole volume by computing the volume ratio between echolucent and echogenic areas. The plaque heterogeneity was obtained by computing the density of echogenic areas per volume unit. Parametric t test was used for statistic analysis.Results. Minimum volume GSM ratio (determining echolucency was higher for asymptomatic plaque (0.6 – CI 0.48– 0.91 versus 0.3 – CI 0.21–0.75: p = 0.002. Greater GSM heterogeneity was present in symptomatic plaque (6.8 – CI 2.5– 18.3 versus 0.41 – CI 0.2–3.4;.p = 0.0001.Conclusions. Volume ultrasound imaging that enables objective assessment of whole ultrasonic plaque structure is more sensitive that single longitudinal view sonography for differentiating between ultrasonic structure of symptomatic and asymptomatic plaque.

Two-Dimensional Echocardiography Estimates of Fetal Ventricular Mass throughout Gestation.

Science.gov (United States)

Aye, Christina Y L; Lewandowski, Adam James; Ohuma, Eric O; Upton, Ross; Packham, Alice; Kenworthy, Yvonne; Roseman, Fenella; Norris, Tess; Molloholli, Malid; Wanyonyi, Sikolia; Papageorghiou, Aris T; Leeson, Paul

2017-08-12

Two-dimensional (2D) ultrasound quality has improved in recent years. Quantification of cardiac dimensions is important to screen and monitor certain fetal conditions. We assessed the feasibility and reproducibility of fetal ventricular measures using 2D echocardiography, reported normal ranges in our cohort, and compared estimates to other modalities. Mass and end-diastolic volume were estimated by manual contouring in the four-chamber view using TomTec Image Arena 4.6 in end diastole. Nomograms were created from smoothed centiles of measures, constructed using fractional polynomials after log transformation. The results were compared to those of previous studies using other modalities. A total of 294 scans from 146 fetuses from 15+0 to 41+6 weeks of gestation were included. Seven percent of scans were unanalysable and intraobserver variability was good (intraclass correlation coefficients for left and right ventricular mass 0.97 [0.87-0.99] and 0.99 [0.95-1.0], respectively). Mass and volume increased exponentially, showing good agreement with 3D mass estimates up to 28 weeks of gestation, after which our measurements were in better agreement with neonatal cardiac magnetic resonance imaging. There was good agreement with 4D volume estimates for the left ventricle. Current state-of-the-art 2D echocardiography platforms provide accurate, feasible, and reproducible fetal ventricular measures across gestation, and in certain circumstances may be the modality of choice. © 2017 S. Karger AG, Basel.

Diagnostic utility of three-dimensional power Doppler ultrasound for postmenopausal bleeding.

Science.gov (United States)

Kim, Ari; Lee, Ji Young; Chun, Sungwook; Kim, Heung Yeol

2015-06-01

We evaluated the role of three-dimensional power Doppler ultrasound (3D PD-US) to detect endometrial lesions in women with postmenopausal endometrial bleeding. In this prospective observational study, from January 2009 to November 2012, we recruited 225 postmenopausal women with postmenopausal uterine bleeding who met the study criteria. Women who had hematologic disease, chronic medical diseases, or nonuterine pelvic diseases were excluded. Prior to endometrial biopsy, the patients underwent a baseline transvaginal ultrasound screening. The vascular indices and endometrial volumes were calculated with 3D PD-US and compared with the endometrial histopathology. Among the endometrial histopathologic findings of 174 women, atrophic endometrium was the most common finding (30.5%). Endometrial malignancy was confirmed in 28 cases (16.1%), and endometrial hyperplasia was diagnosed in 17 cases (9.8%). The prevalence of endometrial cancer was high in patients who had endometrial thickness >9.5 mm (p < 0.001) and volume greater than 4.05 mL (p < 0.001). For the endometrial carcinoma only, the cutoff values of vascular index, flow index, and vascular flow index for predicting malignancy were 13.070, 12.610, and 3.764, respectively. For endometrial hyperplasia, endometrial thickness and vascular flow index were significant findings. Endometrial vasculature and volume can be obtained using 3D PD-US. The diagnostic usefulness of 3D PD-US for endometrial diseases is promising in women with postmenopausal endometrial bleeding. Copyright © 2015. Published by Elsevier B.V.

Assessment of RELAP5-3D copyright using data from two-dimensional RPI flow tests

International Nuclear Information System (INIS)

Davis, C.B.

1998-01-01

The capability of the RELAP5-3D copyright computer code to perform multi-dimensional thermal-hydraulic analysis was assessed using data from steady-state flow tests conducted at Rensselaer Polytechnic Institute (RPI). The RPI data were taken in a two-dimensional test section in a low-pressure air/water loop. The test section consisted of a thin vertical channel that simulated a two-dimensional slice through the core of a pressurized water reactor. Single-phase and two-phase flows were supplied to the test section in an asymmetric manner to generate a two-dimensional flow field. A traversing gamma densitometer was used to measure void fraction at many locations in the test section. High speed photographs provided information on the flow patterns and flow regimes. The RPI test section was modeled using the multi-dimensional component in RELAP5-3D Version BF06. Calculations of three RPI experiments were performed. The flow regimes predicted by the base code were in poor agreement with those observed in the tests. The two-phase regions were observed to be in the bubbly and slug flow regimes in the test. However, nearly all of the junctions in the horizontal direction were calculated to be in the stratified flow regime because of the relatively low velocities in that direction. As a result, the void fraction predictions were also in poor agreement with the measured values. Significantly improved results were obtained in sensitivity calculations with a modified version of the code that prevented the horizontal junctions from entering the stratified flow regime. These results indicate that the code's logic in the determination of flow regimes in a multi-dimensional component must be improved. The results of the sensitivity calculations also indicate that RELAP5-3D will provide a significant multi-dimensional hydraulic analysis capability once the flow regime prediction is improved

Satisfactory rate of post-processing visualization of fetal cerebral axial, sagittal, and coronal planes from three-dimensional volumes acquired in routine second trimester ultrasound practice by sonographers of peripheral centers.

Science.gov (United States)

Rizzo, Giuseppe; Pietrolucci, Maria Elena; Capece, Giuseppe; Cimmino, Ernesto; Colosi, Enrico; Ferrentino, Salvatore; Sica, Carmine; Di Meglio, Aniello; Arduini, Domenico

2011-08-01

The aim of this study was to evaluate the feasibility to visualize central nervous system (CNS) diagnostic planes from three-dimensional (3D) brain volumes obtained in ultrasound facilities with no specific experience in fetal neurosonography. Five sonographers prospectively recorded transabdominal 3D CNS volumes starting from an axial approach on 500 consecutive pregnancies at 19-24 weeks of gestation undergoing routine ultrasound examination. Volumes were sent to the referral center (Department of Obstetrics and Gynecology, Università Roma Tor Vergata, Italy) and two independent reviewers with experience in 3D ultrasound assessed their quality in the display of axial, coronal, and sagittal planes. CNS volumes were acquired in 491/500 pregnancies (98.2%). The two reviewers acknowledged the presence of satisfactory images with a visualization rate ranging respectively between 95.1% and 97.14% for axial planes, 73.72% and 87.16% for coronal planes, and 78.41% and 94.29% for sagittal planes. The agreement rate between the two reviewers as expressed by Cohen's kappa coefficient was >0.87 for axial planes, >0.89 for coronal planes, and >0.94 for sagittal planes. The presence of a maternal body mass index >30 alters the probability of achieving satisfactory CNS views, while existence of previous maternal lower abdomen surgery does not affect the quality of the reconstructed planes. CNS volumes acquired by 3D ultrasonography in peripheral centers showed a quality high enough to allow a detailed fetal neurosonogram.

Accuracy of volume measurement using 3D ultrasound and development of CT-3D US image fusion algorithm for prostate cancer radiotherapy

International Nuclear Information System (INIS)

Baek, Jihye; Huh, Jangyoung; Hyun An, So; Oh, Yoonjin; Kim, Myungsoo; Kim, DongYoung; Chung, Kwangzoo; Cho, Sungho; Lee, Rena

2013-01-01

Purpose: To evaluate the accuracy of measuring volumes using three-dimensional ultrasound (3D US), and to verify the feasibility of the replacement of CT-MR fusion images with CT-3D US in radiotherapy treatment planning. Methods: Phantoms, consisting of water, contrast agent, and agarose, were manufactured. The volume was measured using 3D US, CT, and MR devices. A CT-3D US and MR-3D US image fusion software was developed using the Insight Toolkit library in order to acquire three-dimensional fusion images. The quality of the image fusion was evaluated using metric value and fusion images. Results: Volume measurement, using 3D US, shows a 2.8 ± 1.5% error, 4.4 ± 3.0% error for CT, and 3.1 ± 2.0% error for MR. The results imply that volume measurement using the 3D US devices has a similar accuracy level to that of CT and MR. Three-dimensional image fusion of CT-3D US and MR-3D US was successfully performed using phantom images. Moreover, MR-3D US image fusion was performed using human bladder images. Conclusions: 3D US could be used in the volume measurement of human bladders and prostates. CT-3D US image fusion could be used in monitoring the target position in each fraction of external beam radiation therapy. Moreover, the feasibility of replacing the CT-MR image fusion to the CT-3D US in radiotherapy treatment planning was verified.

Chest wall segmentation in automated 3D breast ultrasound scans.

Science.gov (United States)

Tan, Tao; Platel, Bram; Mann, Ritse M; Huisman, Henkjan; Karssemeijer, Nico

2013-12-01

In this paper, we present an automatic method to segment the chest wall in automated 3D breast ultrasound images. Determining the location of the chest wall in automated 3D breast ultrasound images is necessary in computer-aided detection systems to remove automatically detected cancer candidates beyond the chest wall and it can be of great help for inter- and intra-modal image registration. We show that the visible part of the chest wall in an automated 3D breast ultrasound image can be accurately modeled by a cylinder. We fit the surface of our cylinder model to a set of automatically detected rib-surface points. The detection of the rib-surface points is done by a classifier using features representing local image intensity patterns and presence of rib shadows. Due to attenuation of the ultrasound signal, a clear shadow is visible behind the ribs. Evaluation of our segmentation method is done by computing the distance of manually annotated rib points to the surface of the automatically detected chest wall. We examined the performance on images obtained with the two most common 3D breast ultrasound devices in the market. In a dataset of 142 images, the average mean distance of the annotated points to the segmented chest wall was 5.59 ± 3.08 mm. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of an automated breast 3D-ultrasound system by comparing it with hand-held ultrasound (HHUS) and mammography.

Science.gov (United States)

Golatta, Michael; Baggs, Christina; Schweitzer-Martin, Mirjam; Domschke, Christoph; Schott, Sarah; Harcos, Aba; Scharf, Alexander; Junkermann, Hans; Rauch, Geraldine; Rom, Joachim; Sohn, Christof; Heil, Joerg

2015-04-01

Automated three-dimensional (3D) breast ultrasound (US) systems are meant to overcome the shortcomings of hand-held ultrasound (HHUS). The aim of this study is to analyze and compare clinical performance of an automated 3D-US system by comparing it with HHUS, mammography and the clinical gold standard (defined as the combination of HHUS, mammography and-if indicated-histology). Nine hundred and eighty three patients (=1,966 breasts) were enrolled in this monocentric, explorative and prospective cohort study. All examinations were analyzed blinded to the patients´ history and to the results of the routine imaging. The agreement of automated 3D-US with HHUS, mammography and the gold standard was assessed with kappa statistics. Sensitivity, specificity and positive and negative predictive value were calculated to assess the test performance. Blinded to the results of the gold standard the agreement between automated 3D-US and HHUS or mammography was fair, given by a Kappa coefficient of 0.31 (95% CI [0.26;0.36], p automated 3D-US the sensitivity improved to 84% (NPV = 99%, specificity = 85%). The results of this study let us suggest, that automated 3D-US might be a helpful new tool in breast imaging, especially in screening.

3D Flow reconstruction using ultrasound PIV

Science.gov (United States)

Poelma, C.; Mari, J. M.; Foin, N.; Tang, M.-X.; Krams, R.; Caro, C. G.; Weinberg, P. D.; Westerweel, J.

2011-04-01

Ultrasound particle image velocimetry (PIV) can be used to obtain velocity fields in non-transparent geometries and/or fluids. In the current study, we use this technique to document the flow in a curved tube, using ultrasound contrast bubbles as flow tracer particles. The performance of the technique is first tested in a straight tube, with both steady laminar and pulsatile flows. Both experiments confirm that the technique is capable of reliable measurements. A number of adaptations are introduced that improve the accuracy and applicability of ultrasound PIV. Firstly, due to the method of ultrasound image acquisition, a correction is required for the estimation of velocities from tracer displacements. This correction accounts for the fact that columns in the image are recorded at slightly different instances. The second improvement uses a slice-by-slice scanning approach to obtain three-dimensional velocity data. This approach is here demonstrated in a strongly curved tube. The resulting flow profiles and wall shear stress distribution shows a distinct asymmetry. To meaningfully interpret these three-dimensional results, knowledge of the measurement thickness is required. Our third contribution is a method to determine this quantity, using the correlation peak heights. The latter method can also provide the third (out-of-plane) component if the measurement thickness is known, so that all three velocity components are available using a single probe.

Method for coupling two-dimensional to three-dimensional discrete ordinates calculations

International Nuclear Information System (INIS)

Thompson, J.L.; Emmett, M.B.; Rhoades, W.A.; Dodds, H.L. Jr.

1985-01-01

A three-dimensional (3-D) discrete ordinates transport code, TORT, has been developed at the Oak Ridge National Laboratory for radiation penetration studies. It is not feasible to solve some 3-D penetration problems with TORT, such as a building located a large distance from a point source, because (a) the discretized 3-D problem is simply too big to fit on the computer or (b) the computing time (and corresponding cost) is prohibitive. Fortunately, such problems can be solved with a hybrid approach by coupling a two-dimensional (2-D) description of the point source, which is assumed to be azimuthally symmetric, to a 3-D description of the building, the region of interest. The purpose of this paper is to describe this hybrid methodology along with its implementation and evaluation in the DOTTOR (Discrete Ordinates to Three-dimensional Oak Ridge Transport) code

Variability of global left ventricular deformation analysis using vendor dependent and independent two-dimensional speckle-tracking software in adults

DEFF Research Database (Denmark)

Risum, Niels; Ali, Sophia; Olsen, Niels T

2012-01-01

Evaluation of myocardial deformation by two-dimensional speckle-tracking is useful for clinical and research purposes. However, differences may exist among different ultrasound machines, software packages, frame rates, and observers.......Evaluation of myocardial deformation by two-dimensional speckle-tracking is useful for clinical and research purposes. However, differences may exist among different ultrasound machines, software packages, frame rates, and observers....

Two-dimensional membranes in motion

NARCIS (Netherlands)

Davidovikj, D.

2018-01-01

This thesis revolves around nanomechanical membranes made of suspended two - dimensional materials. Chapters 1-3 give an introduction to the field of 2D-based nanomechanical devices together with an overview of the underlying physics and the measurementtools used in subsequent chapters. The research

Non-invasive Estimation of Pressure Changes using 2-D Vector Velocity Ultrasound: An Experimental Study with In-Vivo Examples

DEFF Research Database (Denmark)

Olesen, Jacob Bjerring; Villagómez Hoyos, Carlos Armando; Møller, Niclas Dechau

2018-01-01

and at the aortic valve of two healthy volunteers. Ultrasound measurements were performed using the experimental scanner SARUS, in combination with an 8MHz linear array transducer for experimental scans and a carotid scan, whereas a 3.5MHz phased array probe was employed for a scan of an aortic valve. Measured 2-D......A non-invasive method for estimating intravascular pressure changes using 2-D vector velocity is presented. The method was first validated on computational fluid dynamics (CFD) data, and with catheter measurements on phantoms. Hereafter, the method was tested in-vivo at the carotid bifurcation...

Interfacial nondegenerate doping of MoS2 and other two-dimensional semiconductors.

Science.gov (United States)

Behura, Sanjay; Berry, Vikas

2015-03-24

Controlled nondegenerate doping of two-dimensional semiconductors (2DSs) with their ultraconfined carriers, high quantum capacitance, and surface-sensitive electronics can enable tuning their Fermi levels for rational device design. However, doping techniques for three-dimensional semiconductors, such as ion implantation, cannot be directly applied to 2DSs because they inflict high defect density. In this issue of ACS Nano, Park et al. demonstrate that interfacing 2DSs with substrates having dopants can controllably inject carriers to achieve nondegenerate doping, thus significantly broadening 2DSs' functionality and applications. Futuristically, this can enable complex spatial patterning/contouring of energy levels in 2DSs to form p-n junctions, integrated logic, and opto/electronic devices. The process is also extendable to biocellular-interfaced devices, band-continuum structures, and intricate 2D circuitry.

Ultrasound -- Pelvis

Medline Plus

Full Text Available ... uterus). Sonohysterography allows for a more in-depth investigation of the uterine cavity . Three-dimensional (3-D) ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

Ultrasound -- Pelvis

Medline Plus

Full Text Available ... uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries in planes that ... a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ...

[Ultrasound findings in rhabdomyolysis].

Science.gov (United States)

Carrillo-Esper, Raúl; Galván-Talamantes, Yazmin; Meza-Ayala, Cynthia Margarita; Cruz-Santana, Julio Alberto; Bonilla-Reséndiz, Luis Ignacio

Rhabdomyolysis is defined as skeletal muscle necrosis. Ultrasound assessment has recently become a useful tool for the diagnosis and monitoring of muscle diseases, including rhabdomyolysis. A case is presented on the ultrasound findings in a patient with rhabdomyolysis. To highlight the importance of ultrasound as an essential part in the diagnosis in rhabdomyolysis, to describe the ultrasound findings, and review the literature. A 30 year-old with post-traumatic rhabdomyolysis of both thighs. Ultrasound was performed using a Philips Sparq model with a high-frequency linear transducer (5-10MHz), in low-dimensional scanning mode (2D), in longitudinal and transverse sections at the level of both thighs. The images obtained showed disorganisation of the orientation of the muscle fibres, ground glass image, thickening of the muscular fascia, and the presence of anechoic areas. Ultrasound is a useful tool in the evaluation of rhabdomyolysis. Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Parameters of two-dimensional perineal ultrasonography for evaluation of urinary incontinence after Radical Prostatectomy.

Science.gov (United States)

Costa Cruz, Danilo Souza Lima da; D'Ancona, Carlos Arturo Levi; Baracat, Jamal; Alves, Marco Antonio Dionisio; Cartapatti, Marcelo; Damião, Ronaldo

2014-01-01

Urinary incontinence remains a major concern for patients undergoing radical prostatectomy. Its prevalence can reach 20% in the late postoperative period. This clinical study investigated the differences of a dynamic evaluation of the urethra and pelvic floor contraction using perineal ultrasound in men without prostate surgery and in men submitted to radical prostatectomy with and without stress urinary incontinence. Ninety two male patients were included, which 70% of them underwent radical prostatectomy (RP) for more than one year. Thirty one men with clinically post prostatectomy incontinence were compared by two-dimensional (2D) perineal ultrasound to 34 patients without post prostatectomy incontinence and to 27 men without surgery in two centers in Brazil. Our results showed that the continent group presented the urethral angle at rest significantly lower than the prostate group (p = 0.0002). We also observed that the incontinent group showed the displacement of the anterior bladder neck during contraction significantly lower than the continent group (p = 0.008). We found that the continent group presented the urethral angle at rest significantly lower than the prostate group. The incontinent group also showed the anterior bladder neck displacement during contraction significantly lower than the continent group. It was more evident when the severe incontinent group and the continent group were compared.

Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound.

Science.gov (United States)

Mercado, Karla P; Helguera, María; Hocking, Denise C; Dalecki, Diane

2015-07-01

Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13-47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices.

Are 3D ultrasound and office hysteroscopy useful for the assessment of uterine cavity after late foetal loss?

Science.gov (United States)

Thellier, E; Levaillant, J-M; Pourcelot, A-G; Houllier, M; Fernandez, H; Capmas, P

2018-05-01

To assess the efficacy of office hysteroscopy and 3D ultrasound for the diagnostic of uterine anomalies after late foetal loss. This retrospective observational study took place in the gynaecologic unit of a teaching hospital from 2009 to 2014. Women with late foetal loss (<22 weeks of gestation) had an office hysteroscopy and 3D ultrasound within three months after delivery. The results of the ultrasound and hysteroscopy were recorded and compared. Eighty women were included with a mean age of 29.8 years (28.2-31.4). Forty-seven women had both hysteroscopy and 3D ultrasound, and a uterine cavity's anomaly (bicornuate uterus, T-Shape uterus and septate uterus) was found in ten women (21%) at 3D sonography and in 13 women (28%) at office hysteroscopy. Concordance between the two exams was very good with a kappa at 0.83. In three cases, a uterine cavity's anomaly was found at hysteroscopy whereas sonography was normal. Anomalies at ultrasound (uterine cavity's anomaly, myometrium anomaly or ovarian anomaly) were found in 27.6% of cases. Both 3D ultrasound and office hysteroscopy are useful for assessment of the uterine cavity after late foetal loss. The application of these two exams is important, as hysteroscopy is generally used for assessment of the uterine cavity and endometrium, while 3D ultrasound is generally used to identify the precise type of uterine malformation and for the examination of the myometrium and annexes. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

FLUST-2D - A computer code for the calculation of the two-dimensional flow of a compressible medium in coupled retangular areas

International Nuclear Information System (INIS)

Enderle, G.

1979-01-01

The computer-code FLUST-2D is able to calculate the two-dimensional flow of a compressible fluid in arbitrary coupled rectangular areas. In a finite-difference scheme the program computes pressure, density, internal energy and velocity. Starting with a basic set of equations, the difference equations in a rectangular grid are developed. The computational cycle for coupled fluid areas is described. Results of test calculations are compared to analytical solutions and the influence of time step and mesh size are investigated. The program was used to precalculate the blowdown experiments of the HDR experimental program. Downcomer, plena, internal vessel region, blowdown pipe and a containment area have been modelled two-dimensionally. The major results of the precalculations are presented. This report also contains a description of the code structure and user information. (orig.) [de

Two-Dimensional Halide Perovskites for Emerging New- Generation Photodetectors

DEFF Research Database (Denmark)

Tang, Yingying; Cao, Xianyi; Chi, Qijin

2018-01-01

Compared to their conventional three-dimensional (3D) counterparts, two-dimensional (2D) halide perovskites have attracted more interests recently in a variety of areas related to optoelectronics because of their unique structural characteristics and enhanced performances. In general, there are two...... distinct types of 2D halide perovskites. One represents those perovskites with an intrinsic layered crystal structure (i.e. MX6 layers, M = metal and X = Cl, Br, I), the other defines the perovskites with a 2D nanostructured morphology such as nanoplatelets and nanosheets. Recent studies have shown that 2D...... halide perovskites hold promising potential for the development of new-generation photodetectors, mainly arising from their highly efficient photoluminescence and absorbance, color tunability in the visible-light range and relatively high stability. In this chapter, we present the summary and highlights...

GPU-accelerated Kernel Regression Reconstruction for Freehand 3D Ultrasound Imaging.

Science.gov (United States)

Wen, Tiexiang; Li, Ling; Zhu, Qingsong; Qin, Wenjian; Gu, Jia; Yang, Feng; Xie, Yaoqin

2017-07-01

Volume reconstruction method plays an important role in improving reconstructed volumetric image quality for freehand three-dimensional (3D) ultrasound imaging. By utilizing the capability of programmable graphics processing unit (GPU), we can achieve a real-time incremental volume reconstruction at a speed of 25-50 frames per second (fps). After incremental reconstruction and visualization, hole-filling is performed on GPU to fill remaining empty voxels. However, traditional pixel nearest neighbor-based hole-filling fails to reconstruct volume with high image quality. On the contrary, the kernel regression provides an accurate volume reconstruction method for 3D ultrasound imaging but with the cost of heavy computational complexity. In this paper, a GPU-based fast kernel regression method is proposed for high-quality volume after the incremental reconstruction of freehand ultrasound. The experimental results show that improved image quality for speckle reduction and details preservation can be obtained with the parameter setting of kernel window size of [Formula: see text] and kernel bandwidth of 1.0. The computational performance of the proposed GPU-based method can be over 200 times faster than that on central processing unit (CPU), and the volume with size of 50 million voxels in our experiment can be reconstructed within 10 seconds.

Application of 3D and 2D quantitative shear wave elastography (SWE) to differentiate between benign and malignant breast masses.

Science.gov (United States)

Tian, Jie; Liu, Qianqi; Wang, Xi; Xing, Ping; Yang, Zhuowen; Wu, Changjun

2017-01-20

As breast cancer tissues are stiffer than normal tissues, shear wave elastography (SWE) can locally quantify tissue stiffness and provide histological information. Moreover, tissue stiffness can be observed on three-dimensional (3D) colour-coded elasticity maps. Our objective was to evaluate the diagnostic performances of quantitative features in differentiating breast masses by two-dimensional (2D) and 3D SWE. Two hundred ten consecutive women with 210 breast masses were examined with B-mode ultrasound (US) and SWE. Quantitative features of 3D and 2D SWE were assessed, including elastic modulus standard deviation (E SD E ) measured on SWE mode images and E SD U measured on B-mode images, as well as maximum elasticity (E max ). Adding quantitative features to B-mode US improved the diagnostic performance (p < 0.05) and reduced false-positive biopsies (p < 0.0001). The area under the receiver operating characteristic curve (AUC) of 3D SWE was similar to that of 2D SWE for E SD E (p = 0.026) and E SD U (p = 0.159) but inferior to that of 2D SWE for E max (p = 0.002). Compared with E SD U , E SD E showed a higher AUC on 2D (p = 0.0038) and 3D SWE (p = 0.0057). Our study indicates that quantitative features of 3D and 2D SWE can significantly improve the diagnostic performance of B-mode US, especially 3D SWE E SD E , which shows considerable clinical value.

Two-dimensional Cu2Si sheet: a promising electrode material for nanoscale electronics

Science.gov (United States)

Meng Yam, Kah; Guo, Na; Zhang, Chun

2018-06-01

Building electronic devices on top of two-dimensional (2D) materials has recently become one of most interesting topics in nanoelectronics. Finding high-performance 2D electrode materials is one central issue in 2D nanoelectronics. In the current study, based on first-principles calculations, we compare the electronic and transport properties of two nanoscale devices. One device consists of two single-atom-thick planar Cu2Si electrodes, and a nickel phthalocyanine (NiPc) molecule in the middle. The other device is made of often-used graphene electrodes and a NiPc molecule. Planer Cu2Si is a new type of 2D material that was recently predicted to exist and be stable under room temperature [11]. We found that at low bias voltages, the electric current through the Cu2Si–NiPc–Cu2Si junction is about three orders higher than that through graphene–NiPc–graphene. Detailed analysis shows that the surprisingly high conductivity of Cu2Si–NiPc–Cu2Si originates from the mixing of the Cu2Si state near Fermi energy and the highest occupied molecular orbital of NiPc. These results suggest that 2D Cu2Si may be an excellent candidate for electrode materials for future nanoscale devices.

Equatorial spread F studies using SAMI3 with two-dimensional and three-dimensional electrostatics

Directory of Open Access Journals (Sweden)

H. C. Aveiro

2013-12-01

Full Text Available This letter presents a study of equatorial F region irregularities using the NRL SAMI3/ESF model, comparing results using a two-dimensional (2-D and a three-dimensional (3-D electrostatic potential solution. For the 3-D potential solution, two cases are considered for parallel plasma transport: (1 transport based on the parallel ambipolar field, and (2 transport based on the parallel electric field. The results show that the growth rate of the generalized Rayleigh–Taylor instability is not affected by the choice of the potential solution. However, differences are observed in the structures of the irregularities between the 2-D and 3-D solutions. Additionally, the plasma velocity along the geomagnetic field computed using the full 3-D solution shows complex structures that are not captured by the simplified model. This points out that only the full 3-D model is able to fully capture the complex physics of the equatorial F region.

Binding energy of two-dimensional biexcitons

DEFF Research Database (Denmark)

Singh, Jai; Birkedal, Dan; Vadim, Lyssenko

1996-01-01

Using a model structure for a two-dimensional (2D) biexciton confined in a quantum well, it is shown that the form of the Hamiltonian of the 2D biexciton reduces into that of an exciton. The binding energies and Bohr radii of a 2D biexciton in its various internal energy states are derived...... analytically using the fractional dimension approach. The ratio of the binding energy of a 2D biexciton to that of a 2D exciton is found to be 0.228, which agrees very well with the recent experimental value. The results of our approach are compared with those of earlier theories....

Iterative Two- and One-Dimensional Methods for Three-Dimensional Neutron Diffusion Calculations

International Nuclear Information System (INIS)

Lee, Hyun Chul; Lee, Deokjung; Downar, Thomas J.

2005-01-01

Two methods are proposed for solving the three-dimensional neutron diffusion equation by iterating between solutions of the two-dimensional (2-D) radial and one-dimensional (1-D) axial solutions. In the first method, the 2-D/1-D equations are coupled using a current correction factor (CCF) with the average fluxes of the lower and upper planes and the axial net currents at the plane interfaces. In the second method, an analytic expression for the axial net currents at the interface of the planes is used for planar coupling. A comparison of the new methods is made with two previously proposed methods, which use interface net currents and partial currents for planar coupling. A Fourier convergence analysis of the four methods was performed, and results indicate that the two new methods have at least three advantages over the previous methods. First, the new methods are unconditionally stable, whereas the net current method diverges for small axial mesh size. Second, the new methods provide better convergence performance than the other methods in the range of practical mesh sizes. Third, the spectral radii of the new methods asymptotically approach zero as the mesh size increases, while the spectral radius of the partial current method approaches a nonzero value as the mesh size increases. Of the two new methods proposed here, the analytic method provides a smaller spectral radius than the CCF method, but the CCF method has several advantages over the analytic method in practical applications

Two- and three-dimensional transvaginal ultrasound with power Doppler angiography and gel infusion sonography for diagnosis of endometrial malignancy.

Science.gov (United States)

Dueholm, M; Christensen, J W; Rydbjerg, S; Hansen, E S; Ørtoft, G

2015-06-01

To evaluate the diagnostic efficiency of two-dimensional (2D) and three-dimensional (3D) transvaginal ultrasonography, power Doppler angiography (PDA) and gel infusion sonography (GIS) at offline analysis for recognition of malignant endometrium compared with real-time evaluation during scanning, and to determine optimal image parameters at 3D analysis. One hundred and sixty-nine consecutive women with postmenopausal bleeding and endometrial thickness ≥ 5 mm underwent systematic evaluation of endometrial pattern on 2D imaging, and 2D videoclips and 3D volumes were later analyzed offline. Histopathological findings at hysteroscopy or hysterectomy were used as the reference standard. The efficiency of the different techniques for diagnosis of malignancy was calculated and compared. 3D image parameters, endometrial volume and 3D vascular indices were assessed. Optimal 3D image parameters were transformed by logistic regression into a risk of endometrial cancer (REC) score, including scores for body mass index, endometrial thickness and endometrial morphology at gray-scale and PDA and GIS. Offline 2D and 3D analysis were equivalent, but had lower diagnostic performance compared with real-time evaluation during scanning. Their diagnostic performance was not markedly improved by the addition of PDA or GIS, but their efficiency was comparable with that of real-time 2D-GIS in offline examinations of good image quality. On logistic regression, the 3D parameters from the REC-score system had the highest diagnostic efficiency. The area under the curve of the REC-score system at 3D-GIS (0.89) was not improved by inclusion of vascular indices or endometrial volume calculations. Real-time evaluation during scanning is most efficient, but offline 2D and 3D analysis is useful for prediction of endometrial cancer when good image quality can be obtained. The diagnostic efficiency at 3D analysis may be improved by use of REC-scoring systems, without the need for calculation of

Ultrasound-mediated microbubble enhancement of radiation therapy studied using three-dimensional high-frequency power Doppler ultrasound.

Science.gov (United States)

Kwok, Sheldon J J; El Kaffas, Ahmed; Lai, Priscilla; Al Mahrouki, Azza; Lee, Justin; Iradji, Sara; Tran, William Tyler; Giles, Anoja; Czarnota, Gregory J

2013-11-01

Tumor responses to high-dose (>8 Gy) radiation therapy are tightly connected to endothelial cell death. In the study described here, we investigated whether ultrasound-activated microbubbles can locally enhance tumor response to radiation treatments of 2 and 8 Gy by mechanically perturbing the endothelial lining of tumors. We evaluated vascular changes resulting from combined microbubble and radiation treatments using high-frequency 3-D power Doppler ultrasound in a breast cancer xenograft model. We compared treatment effects and monitored vasculature damage 3 hours, 24 hours and 7 days after treatment delivery. Mice treated with 2 Gy radiation and ultrasound-activated microbubbles exhibited a decrease in vascular index to 48 ± 10% at 24 hours, whereas vascular indices of mice treated with 2 Gy radiation alone or microbubbles alone were relatively unchanged at 95 ± 14% and 78 ± 14%, respectively. These results suggest that ultrasound-activated microbubbles enhance the effects of 2 Gy radiation through a synergistic mechanism, resulting in alterations of tumor blood flow. This novel therapy may potentiate lower radiation doses to preferentially target endothelial cells, thus reducing effects on neighboring normal tissue and increasing the efficacy of cancer treatments. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

D-brane propagation in two-dimensional black hole geometries

International Nuclear Information System (INIS)

Nakayama, Yu; Rey, Soo-Jong; Sugawara, Yuji

2005-01-01

We study propagation of D0-brane in two-dimensional lorentzian black hole backgrounds by the method of boundary conformal field theory of SL(2,R)/U(1) supercoset at level k. Typically, such backgrounds arise as near-horizon geometries of k coincident non-extremal NS5-branes, where 1/k measures curvature of the backgrounds in string unit and hence size of string worldsheet effects. At classical level, string worldsheet effects are suppressed and D0-brane propagation in the lorentzian black hole geometry is simply given by the Wick rotation of D1-brane contour in the euclidean black hole geometry. Taking account of string worldsheet effects, boundary state of the lorentzian D0-brane is formally constructible via Wick rotation from that of the euclidean D1-brane. However, the construction is subject to ambiguities in boundary conditions. We propose exact boundary states describing the D0-brane, and clarify physical interpretations of various boundary states constructed from different boundary conditions. As it falls into the black hole, the D0-brane radiates off to the horizon and to the infinity. From the boundary states constructed, we compute physical observables of such radiative process. We find that part of the radiation to infinity is in effective thermal distribution at the Hawking temperature. We also find that part of the radiation to horizon is in the Hagedorn distribution, dominated by massive, highly non-relativistic closed string states, much like the tachyon matter. Remarkably, such distribution emerges only after string worldsheet effects are taken exactly into account. From these results, we observe that nature of the radiation distribution changes dramatically across the conifold geometry k = 1 (k = 3 for the bosonic case), exposing the 'string - black hole transition' therein

Strain-engineered growth of two-dimensional materials.

Science.gov (United States)

Ahn, Geun Ho; Amani, Matin; Rasool, Haider; Lien, Der-Hsien; Mastandrea, James P; Ager Iii, Joel W; Dubey, Madan; Chrzan, Daryl C; Minor, Andrew M; Javey, Ali

2017-09-20

The application of strain to semiconductors allows for controlled modification of their band structure. This principle is employed for the manufacturing of devices ranging from high-performance transistors to solid-state lasers. Traditionally, strain is typically achieved via growth on lattice-mismatched substrates. For two-dimensional (2D) semiconductors, this is not feasible as they typically do not interact epitaxially with the substrate. Here, we demonstrate controlled strain engineering of 2D semiconductors during synthesis by utilizing the thermal coefficient of expansion mismatch between the substrate and semiconductor. Using WSe 2 as a model system, we demonstrate stable built-in strains ranging from 1% tensile to 0.2% compressive on substrates with different thermal coefficient of expansion. Consequently, we observe a dramatic modulation of the band structure, manifested by a strain-driven indirect-to-direct bandgap transition and brightening of the dark exciton in bilayer and monolayer WSe 2 , respectively. The growth method developed here should enable flexibility in design of more sophisticated devices based on 2D materials.Strain engineering is an essential tool for modifying local electronic properties in silicon-based electronics. Here, Ahn et al. demonstrate control of biaxial strain in two-dimensional materials based on the growth substrate, enabling more complex low-dimensional electronics.

Diagnosis of an Omphalocele with 3 Dimension Ultrasound

Directory of Open Access Journals (Sweden)

Vural Dagli

2006-12-01

Full Text Available Fetal omphalocele is a congenital defect of the abdominal wall that allows some of the abdominal organs to protrude through it. It might be associated with chromosomal abnormalities and fetal anomalies.Two dimension (2D ultrasound is the main diagnosis\tmethod. 3D ultrasound can make the diagnosis easier. In this case report we present an omphalocele diagnosed with ultrasound prenatally. We discuss the role of 2D and 3D ultrasound while diagnosing omphalocele prenatally.

Edge Epitaxy of Two-dimensional MoSe2 and MoS2 Nanosheets on One-dimensional Nanowires

KAUST Repository

Chen, Junze; Wu, Xue-Jun; Gong, Yue; Zhu, Yihan; Yang, Zhenzhong; Li, Bing; Lu, Qipeng; Yu, Yifu; Han, Shikui; Zhang, Zhicheng; Zong, Yun; Han, Yu; Gu, Lin; Zhang, Hua

2017-01-01

the longitudinal direction of one-dimensional (1D) Cu2-xS nanowires (NWs) in an epitaxial manner. The obtained Cu2-xS-TMD heterostructures with tunable loading amount and lateral size of TMD NSs are achieved by the consecutive growth of TMD NSs on Cu2-xS NWs

Polytypism and unexpected strong interlayer coupling in two-dimensional layered ReS2

Science.gov (United States)

Qiao, Xiao-Fen; Wu, Jiang-Bin; Zhou, Linwei; Qiao, Jingsi; Shi, Wei; Chen, Tao; Zhang, Xin; Zhang, Jun; Ji, Wei; Tan, Ping-Heng

2016-04-01

Anisotropic two-dimensional (2D) van der Waals (vdW) layered materials, with both scientific interest and application potential, offer one more dimension than isotropic 2D materials to tune their physical properties. Various physical properties of 2D multi-layer materials are modulated by varying their stacking orders owing to significant interlayer vdW coupling. Multilayer rhenium disulfide (ReS2), a representative anisotropic 2D material, was expected to be randomly stacked and lack interlayer coupling. Here, we demonstrate two stable stacking orders, namely isotropic-like (IS) and anisotropic-like (AI) N layer (NL, N > 1) ReS2 are revealed by ultralow- and high-frequency Raman spectroscopy, photoluminescence and first-principles density functional theory calculation. Two interlayer shear modes are observed in AI-NL-ReS2 while only one shear mode appears in IS-NL-ReS2, suggesting anisotropic- and isotropic-like stacking orders in IS- and AI-NL-ReS2, respectively. This explicit difference in the observed frequencies identifies an unexpected strong interlayer coupling in IS- and AI-NL-ReS2. Quantitatively, the force constants of them are found to be around 55-90% of those of multilayer MoS2. The revealed strong interlayer coupling and polytypism in multi-layer ReS2 may stimulate future studies on engineering physical properties of other anisotropic 2D materials by stacking orders.Anisotropic two-dimensional (2D) van der Waals (vdW) layered materials, with both scientific interest and application potential, offer one more dimension than isotropic 2D materials to tune their physical properties. Various physical properties of 2D multi-layer materials are modulated by varying their stacking orders owing to significant interlayer vdW coupling. Multilayer rhenium disulfide (ReS2), a representative anisotropic 2D material, was expected to be randomly stacked and lack interlayer coupling. Here, we demonstrate two stable stacking orders, namely isotropic-like (IS) and

The Use of 3D Power Doppler Ultrasound in the Quantification of Blood Vessels in Uterine Fibroids: Feasibility and Reproducibility

NARCIS (Netherlands)

Nieuwenhuis, L.L.; Betjes, H.E.; Hehenkamp, W.J.K.; Heymans, M.W.; Brölmann, H.A.M.; Huirne, J.A.F.

2015-01-01

Background: To evaluate the interobserver agreement and discriminating value of three-dimensional power Doppler ultrasound (3D PDUS) in patients with fibroids. Methods: An observational prospective cohort study in 19 patients with fibroids. 3D PDUS was performed by one examiner and evaluated by

Towards 3D ultrasound image based soft tissue tracking: a transrectal ultrasound prostate image alignment system.

Science.gov (United States)

Baumann, Michael; Mozer, Pierre; Daanen, Vincent; Troccaz, Jocelyne

2007-01-01

The emergence of real-time 3D ultrasound (US) makes it possible to consider image-based tracking of subcutaneous soft tissue targets for computer guided diagnosis and therapy. We propose a 3D transrectal US based tracking system for precise prostate biopsy sample localisation. The aim is to improve sample distribution, to enable targeting of unsampled regions for repeated biopsies, and to make post-interventional quality controls possible. Since the patient is not immobilized, since the prostate is mobile and due to the fact that probe movements are only constrained by the rectum during biopsy acquisition, the tracking system must be able to estimate rigid transformations that are beyond the capture range of common image similarity measures. We propose a fast and robust multi-resolution attribute-vector registration approach that combines global and local optimization methods to solve this problem. Global optimization is performed on a probe movement model that reduces the dimensionality of the search space and thus renders optimization efficient. The method was tested on 237 prostate volumes acquired from 14 different patients for 3D to 3D and 3D to orthogonal 2D slices registration. The 3D-3D version of the algorithm converged correctly in 96.7% of all cases in 6.5s with an accuracy of 1.41mm (r.m.s.) and 3.84mm (max). The 3D to slices method yielded a success rate of 88.9% in 2.3s with an accuracy of 1.37mm (r.m.s.) and 4.3mm (max).

Efficient two-dimensional compressive sensing in MIMO radar

Science.gov (United States)

Shahbazi, Nafiseh; Abbasfar, Aliazam; Jabbarian-Jahromi, Mohammad

2017-12-01

Compressive sensing (CS) has been a way to lower sampling rate leading to data reduction for processing in multiple-input multiple-output (MIMO) radar systems. In this paper, we further reduce the computational complexity of a pulse-Doppler collocated MIMO radar by introducing a two-dimensional (2D) compressive sensing. To do so, we first introduce a new 2D formulation for the compressed received signals and then we propose a new measurement matrix design for our 2D compressive sensing model that is based on minimizing the coherence of sensing matrix using gradient descent algorithm. The simulation results show that our proposed 2D measurement matrix design using gradient decent algorithm (2D-MMDGD) has much lower computational complexity compared to one-dimensional (1D) methods while having better performance in comparison with conventional methods such as Gaussian random measurement matrix.

Two-dimensional Kagome photonic bandgap waveguide

DEFF Research Database (Denmark)

Nielsen, Jens Bo; Søndergaard, Thomas; Libori, Stig E. Barkou

2000-01-01

The transverse-magnetic photonic-bandgap-guidance properties are investigated for a planar two-dimensional (2-D) Kagome waveguide configuration using a full-vectorial plane-wave-expansion method. Single-moded well-localized low-index guided modes are found. The localization of the optical modes...... is investigated with respect to the width of the 2-D Kagome waveguide, and the number of modes existing for specific frequencies and waveguide widths is mapped out....

Efficient construction of two-dimensional cluster states with probabilistic quantum gates

International Nuclear Information System (INIS)

Chen Qing; Cheng Jianhua; Wang Kelin; Du Jiangfeng

2006-01-01

We propose an efficient scheme for constructing arbitrary two-dimensional (2D) cluster states using probabilistic entangling quantum gates. In our scheme, the 2D cluster state is constructed with starlike basic units generated from 1D cluster chains. By applying parallel operations, the process of generating 2D (or higher-dimensional) cluster states is significantly accelerated, which provides an efficient way to implement realistic one-way quantum computers

Two-dimensional multiferroics in monolayer group IV monochalcogenides

Science.gov (United States)

Wang, Hua; Qian, Xiaofeng

2017-03-01

Low-dimensional multiferroic materials hold great promises in miniaturized device applications such as nanoscale transducers, actuators, sensors, photovoltaics, and nonvolatile memories. Here, using first-principles theory we predict that two-dimensional (2D) monolayer group IV monochalcogenides including GeS, GeSe, SnS, and SnSe are a class of 2D semiconducting multiferroics with giant strongly-coupled in-plane spontaneous ferroelectric polarization and spontaneous ferroelastic lattice strain that are thermodynamically stable at room temperature and beyond, and can be effectively modulated by elastic strain engineering. Their optical absorption spectra exhibit strong in-plane anisotropy with visible-spectrum excitonic gaps and sizable exciton binding energies, rendering the unique characteristics of low-dimensional semiconductors. More importantly, the predicted low domain wall energy and small migration barrier together with the coupled multiferroic order and anisotropic electronic structures suggest their great potentials for tunable multiferroic functional devices by manipulating external electrical, mechanical, and optical field to control the internal responses, and enable the development of four device concepts including 2D ferroelectric memory, 2D ferroelastic memory, and 2D ferroelastoelectric nonvolatile photonic memory as well as 2D ferroelectric excitonic photovoltaics.

Extended Polymorphism of Two-Dimensional Material

NARCIS (Netherlands)

Yoshida, Masaro; Ye, Jianting; Zhang, Yijin; Imai, Yasuhiko; Kimura, Shigeru; Fujiwara, Akihiko; Nishizaki, Terukazu; Kobayashi, Norio; Nakano, Masaki; Iwasa, Yoshihiro

When controlling electronic properties of bulk materials, we usually assume that the basic crystal structure is fixed. However, in two-dimensional (2D) materials, atomic structure or to functionalize their properties. Various polymorphs can exist in transition metal dichalcogenides (TMDCs) from

Two-dimensional profiling of Xanthomonas campestris pv. viticola ...

African Journals Online (AJOL)

However, the analysis of the 2D-PAGE gel images revealed a larger number of spots in the lysis method when compared to the others. Taking ... Keywords: Bacterial canker, Vitis vinifera, proteomics, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2D-PAGE).

[Assessment of left ventricular twist in type 2 diabetes mellitus by using two-dimensional ultrasound speckle tracking imaging].

Science.gov (United States)

Zhu, Pei-hua; Huang, Jing-yuan; Ye, Meng; Zheng, Zhe-lan

2014-09-01

To evaluate the left ventricular twist characteristics in patients with type 2 diabetes by using two-dimensional speckle tracking imaging (STI). Ninety-three patients with type 2 diabetes admitted in Zhejiang Hospital from May 2012 to September 2013 were enrolled. According to left ventricular ejection fraction (LVEF), patients were divided into two groups: normal left ventricular systolic function group (group A, LVEF≥0.50, n=46) and abnormal left ventricular systolic function group (group B, LVEF Consistency check for STI was conducted to assess its stability and reliability. The Peaktw, AVCtw, and MVOtw in group A were significantly elevated than those in normal controls (Pconsistency limit=-2.8-2.7; within measurer: R=0.964, bias=-0.2, 95% consistency limits=-2.7-2.2). STI can be used for early recognition of abnormal changes of cardiac function in type 2 diabetic mellitus patients, with high stability and reliability.

Clinical value of real time 3D sonohysterography and 2D sonohysterography in comparison to hysteroscopy with subsequent histopathological examination in perimenopausal women with abnormal uterine bleeding.

Science.gov (United States)

Kowalczyk, Dariusz; Guzikowski, Wojciech; Więcek, Jacek; Sioma-Markowska, Urszula

2012-01-01

In many publications the transvaginal ultrasound is regarded as the first step to diagnose the cause of uterine bleeding in perimenopausal women. In order to improve the sensitivity and specificity of the conventional ultrasound physiological saline solution was administered to the uterine cavity and after expansion of its walls the interior uterine cavity was examined. And this procedure is called 2D sonohysterography (SIS 2D). By the ultrasound scanners which enable to get 3D real time image a spatial evaluation of the uterine cavity is possible. Clinical value of the real time 3D sonohysterography and 2D sonohysterography compared to hysteroscopy with histopathological examination in perimenopausal women. The study concerned a group of 97 perimenopausal women with abnormal uterine bleeding. In all of them after a standard transvaginal ultrasonography a catheter was inserted into the uterine cavity. After expansion of the uterine walls by administering about 10 ml of 0,9% saline solution the uterine cavity was examined by conventional sonohysterography. Then a 3D imaging mode was activated and the uterine interior was examined by real time 3D ultrasonography. The ultrasound results were verified by hysteroscopy, the endometrial lesions were removed and underwent a histopathological examination. In two cases the SIS examination was impossible because of uterine cervix atresion. In the rest of examined group the SIS 2D sensitivity and specificity came up to 72 and 96% respectively. In the group of SIS 3D the sensitivity and specificity reached 83 and 99% respectively. Adding SIS 3D, a minimally invasive method, to conventional sonohysterography improves the precision of diagnosis of endometrial pathology, allows to get three-dimensional image of the uterine cavity and enables examination of endometrial lesions. The diagnostic precision of this procedure is similar to the results achieved by hysteroscopy.

Half-metallic ferromagnetism prediction in MoS2-based two-dimensional superlattice from first-principles

Science.gov (United States)

Wen, Yan-Ni; Gao, Peng-Fei; Xia, Ming-Gang; Zhang, Sheng-Li

2018-03-01

Half-metallic ferromagnetism (HMFM) has great potential application in spin filter. However, it is extremely rare, especially in two-dimensional (2D) materials. At present, 2D materials have drawn international interest in spintronic devices. Here, we use ab initio density functional theory (DFT) calculations to study the structural stability and electrical and magnetic properties of the MoS2-based 2D superlattice formed by inserting graphene hexagonal ring in 6 × 6 × 1 MoS2 supercell. Two kinds of structures with hexagonal carbon ring were predicted with structural stability and were shown HMFM. The two structures combine the spin transport capacity of graphene with the magnetism of the defective 2D MoS2. And they have strong covalent bonding between the C and S or Mo atoms near the interface. This work is very useful to help us to design reasonable MoS2-based spin filter.

Confined catalysis under two-dimensional materials

OpenAIRE

Li, Haobo; Xiao, Jianping; Fu, Qiang; Bao, Xinhe

2017-01-01

Small spaces in nanoreactors may have big implications in chemistry, because the chemical nature of molecules and reactions within the nanospaces can be changed significantly due to the nanoconfinement effect. Two-dimensional (2D) nanoreactor formed under 2D materials can provide a well-defined model system to explore the confined catalysis. We demonstrate a general tendency for weakened surface adsorption under the confinement of graphene overlayer, illustrating the feasible modulation of su...

Three-dimensional geometrical changes of the human tibialis anterior muscle and its central aponeurosis measured with three-dimensional ultrasound during isometric contractions

Directory of Open Access Journals (Sweden)

Brent J. Raiteri

2016-07-01

Full Text Available Background. Muscles not only shorten during contraction to perform mechanical work, but they also bulge radially because of the isovolumetric constraint on muscle fibres. Muscle bulging may have important implications for muscle performance, however quantifying three-dimensional (3D muscle shape changes in human muscle is problematic because of difficulties with sustaining contractions for the duration of an in vivo scan. Although two-dimensional ultrasound imaging is useful for measuring local muscle deformations, assumptions must be made about global muscle shape changes, which could lead to errors in fully understanding the mechanical behaviour of muscle and its surrounding connective tissues, such as aponeurosis. Therefore, the aims of this investigation were (a to determine the intra-session reliability of a novel 3D ultrasound (3DUS imaging method for measuring in vivo human muscle and aponeurosis deformations and (b to examine how contraction intensity influences in vivo human muscle and aponeurosis strains during isometric contractions. Methods. Participants (n = 12 were seated in a reclined position with their left knee extended and ankle at 90° and performed isometric dorsiflexion contractions up to 50% of maximal voluntary contraction. 3DUS scans of the tibialis anterior (TA muscle belly were performed during the contractions and at rest to assess muscle volume, muscle length, muscle cross-sectional area, muscle thickness and width, fascicle length and pennation angle, and central aponeurosis width and length. The 3DUS scan involved synchronous B-mode ultrasound imaging and 3D motion capture of the position and orientation of the ultrasound transducer, while successive cross-sectional slices were captured by sweeping the transducer along the muscle. Results. 3DUS was shown to be highly reliable across measures of muscle volume, muscle length, fascicle length and central aponeurosis length (ICC ≥ 0.98, CV < 1%. The TA remained

Bethe ansatz for two-magnon scattering states in 2D and 3D Heisenberg–Ising ferromagnets

Science.gov (United States)

Bibikov, P. N.

2018-04-01

Two different versions of Bethe ansatz are suggested for evaluation of scattering two-magnon states in 2D and 3D Heisenberg–Ising ferromagnets on square and simple cubic lattices. It is shown that the two-magnon sector is subdivided on two subsectors related to non-interacting and scattering magnons. The former subsector possess an integrable regular dynamics and may be described by a natural modification of the usual Bethe Ansatz. The latter one is characterized by a non-integrable chaotic dynamics and may be treated only within discrete degenerative version of Bethe Ansatz previously suggested by the author. Some of these results are generalized for multi-magnon states of the Heisenberg–Ising ferromagnet on a D dimensional hyper cubic lattice. Dedicated to the memory of L D Faddeev.

Two-dimensional characterization of atmospheric profile retrievals from limb sounding observations

International Nuclear Information System (INIS)

Worden, J.R.; Bowman, K.W.; Jones, D.B.

2004-01-01

Limb sounders measure atmospheric radiation that is dependent on atmospheric temperature and constituents that have a radial and angular distribution in Earth-centered coordinates. In order to evaluate the sensitivity of a limb retrieval to radial and angular distributions of trace gas concentrations, we perform and characterize one-dimensional (vertical) and two-dimensional (radial and angular) atmospheric profile retrievals. Our simulated atmosphere for these retrievals is a distribution of carbon monoxide (CO), which represents a plume off the coast of south-east Asia. Both the one-dimensional (1D) and two-dimensional (2D) limb retrievals are characterized by evaluating their averaging kernels and error covariances on a radial and angular grid that spans the plume. We apply this 2D characterization of a limb retrieval to a comparison of the 2D retrieval with the 1D (vertical) retrieval. By characterizing a limb retrieval in two dimensions the location of the air mass where the retrievals are most sensitive can be determined. For this test case the retrievals are most sensitive to the CO concentrations about 2 deg.latitude in front of the tangent point locations. We find the information content for the 2D retrieval is an order of magnitude larger and the degrees of freedom is about a factor of two larger than that of the 1D retrieval primarily because the 2D retrieval can estimate angular distributions of CO concentrations. This 2D characterization allows the radial and angular resolution as well as the degrees of freedom and information content to be computed for these limb retrievals. We also use the 2D averaging kernel to develop a strategy for validation of a limb retrieval with an in situ measurement

Medical ultrasound imaging

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt

2007-01-01

The paper gives an introduction to current medical ultrasound imaging systems. The basics of anatomic and blood flow imaging are described. The properties of medical ultrasound and its focusing are described, and the various methods for two- and three-dimensional imaging of the human anatomy...

Usefulness limitation of 3D-ultrasound diagnosis of breast masses

Energy Technology Data Exchange (ETDEWEB)

Cheon, Yong Seok; Chung, Soo Young; Yang, Ik; Lee, Kyung Won; Kim, Hong Dae; Shin, Sang Joon; Chung, Bong Wha [College of Medicine, Hallym Univ., Seoul (Korea, Republic of)

2001-09-01

To compare 3D ultrasound (3D-US) with 2D ultrasound (2D-US) in terms of their usefulness and limitations in the diagnosis of breast masses. We obtained 2D and 3D US images of 37 breast lesions present in 20 cases of fibroadenoma, nine of cancer, and eight of fibrocystic disease proven in a total of 26 cases [ fibroadenoma (n=13), breast cancer (n=9), fibrocystic disease (n=4)] by histologic examination, and by clinical evaluation and clinical evaluation with sonographic imaging in eleven. When comparing 3D and 2D-US images we had no prior information regarding detection rate according to the size of lesions, whether or not internal and boundary echo patterns could be interpreted, accurate differentiation between tumorous and non-tumorous lesions, or the accuracy with which benign and malignant tumors could be differentiated. For lesions of 1 cm or less in diameter the detection rate of 3D-US was lower than that of 2D-US, but for lesions over 1 cm there was no difference between the two modalities. In fibroadenoma and breast cancer, 3D-US was more useful than 2D-US for the evaluation of both internal and boundary echo, but with fibrocystic disease and in the diagnosis of tumor/non-tumor, there was no significant difference. In breast cancer, however, 3D-US more accurately determined malignancy, and in fibroadenoma, because of the pseudospicule revealed by 3D-US, this modality was less exact in determining benignancy. In the evaluation of internal and boundary echo in breast mass diagnosis, 3D-US was more useful than its 2D counterpart. For lesions of 1 cm or less in diameter, however, the detection rate of 3D-US was more useful than its 2D counterpart. For lesions of 1 cm or less in diameter, however, the detection rate of 3D-US was low, and since in some benign cases a pseudospicule was apparent, the possibility of confusion with malignancy arose. For these reasons, the usefulness of 3D-US was limited.

Usefulness limitation of 3D-ultrasound diagnosis of breast masses

International Nuclear Information System (INIS)

Cheon, Yong Seok; Chung, Soo Young; Yang, Ik; Lee, Kyung Won; Kim, Hong Dae; Shin, Sang Joon; Chung, Bong Wha

2001-01-01

To compare 3D ultrasound (3D-US) with 2D ultrasound (2D-US) in terms of their usefulness and limitations in the diagnosis of breast masses. We obtained 2D and 3D US images of 37 breast lesions present in 20 cases of fibroadenoma, nine of cancer, and eight of fibrocystic disease proven in a total of 26 cases [ fibroadenoma (n=13), breast cancer (n=9), fibrocystic disease (n=4)] by histologic examination, and by clinical evaluation and clinical evaluation with sonographic imaging in eleven. When comparing 3D and 2D-US images we had no prior information regarding detection rate according to the size of lesions, whether or not internal and boundary echo patterns could be interpreted, accurate differentiation between tumorous and non-tumorous lesions, or the accuracy with which benign and malignant tumors could be differentiated. For lesions of 1 cm or less in diameter the detection rate of 3D-US was lower than that of 2D-US, but for lesions over 1 cm there was no difference between the two modalities. In fibroadenoma and breast cancer, 3D-US was more useful than 2D-US for the evaluation of both internal and boundary echo, but with fibrocystic disease and in the diagnosis of tumor/non-tumor, there was no significant difference. In breast cancer, however, 3D-US more accurately determined malignancy, and in fibroadenoma, because of the pseudospicule revealed by 3D-US, this modality was less exact in determining benignancy. In the evaluation of internal and boundary echo in breast mass diagnosis, 3D-US was more useful than its 2D counterpart. For lesions of 1 cm or less in diameter, however, the detection rate of 3D-US was more useful than its 2D counterpart. For lesions of 1 cm or less in diameter, however, the detection rate of 3D-US was low, and since in some benign cases a pseudospicule was apparent, the possibility of confusion with malignancy arose. For these reasons, the usefulness of 3D-US was limited

Violating Bell inequalities maximally for two d-dimensional systems

International Nuclear Information System (INIS)

Chen Jingling; Wu Chunfeng; Oh, C. H.; Kwek, L. C.; Ge Molin

2006-01-01

We show the maximal violation of Bell inequalities for two d-dimensional systems by using the method of the Bell operator. The maximal violation corresponds to the maximal eigenvalue of the Bell operator matrix. The eigenvectors corresponding to these eigenvalues are described by asymmetric entangled states. We estimate the maximum value of the eigenvalue for large dimension. A family of elegant entangled states |Ψ> app that violate Bell inequality more strongly than the maximally entangled state but are somewhat close to these eigenvectors is presented. These approximate states can potentially be useful for quantum cryptography as well as many other important fields of quantum information

The Make 2D-DB II package: conversion of federated two-dimensional gel electrophoresis databases into a relational format and interconnection of distributed databases.

Science.gov (United States)

Mostaguir, Khaled; Hoogland, Christine; Binz, Pierre-Alain; Appel, Ron D

2003-08-01

The Make 2D-DB tool has been previously developed to help build federated two-dimensional gel electrophoresis (2-DE) databases on one's own web site. The purpose of our work is to extend the strength of the first package and to build a more efficient environment. Such an environment should be able to fulfill the different needs and requirements arising from both the growing use of 2-DE techniques and the increasing amount of distributed experimental data.

Decoherence in two-dimensional quantum walks

International Nuclear Information System (INIS)

Oliveira, A. C.; Portugal, R.; Donangelo, R.

2006-01-01

We analyze the decoherence in quantum walks in two-dimensional lattices generated by broken-link-type noise. In this type of decoherence, the links of the lattice are randomly broken with some given constant probability. We obtain the evolution equation for a quantum walker moving on two-dimensional (2D) lattices subject to this noise, and we point out how to generalize for lattices in more dimensions. In the nonsymmetric case, when the probability of breaking links in one direction is different from the probability in the perpendicular direction, we have obtained a nontrivial result. If one fixes the link-breaking probability in one direction, and gradually increases the probability in the other direction from 0 to 1, the decoherence initially increases until it reaches a maximum value, and then it decreases. This means that, in some cases, one can increase the noise level and still obtain more coherence. Physically, this can be explained as a transition from a decoherent 2D walk to a coherent 1D walk

Two-Dimensional Homogeneous Fermi Gases

Science.gov (United States)

Hueck, Klaus; Luick, Niclas; Sobirey, Lennart; Siegl, Jonas; Lompe, Thomas; Moritz, Henning

2018-02-01

We report on the experimental realization of homogeneous two-dimensional (2D) Fermi gases trapped in a box potential. In contrast to harmonically trapped gases, these homogeneous 2D systems are ideally suited to probe local as well as nonlocal properties of strongly interacting many-body systems. As a first benchmark experiment, we use a local probe to measure the density of a noninteracting 2D Fermi gas as a function of the chemical potential and find excellent agreement with the corresponding equation of state. We then perform matter wave focusing to extract the momentum distribution of the system and directly observe Pauli blocking in a near unity occupation of momentum states. Finally, we measure the momentum distribution of an interacting homogeneous 2D gas in the crossover between attractively interacting fermions and bosonic dimers.

[Simultaneous determination of vitamins A, D3 and E in infant formula and adult nutritions by online two-dimensional liquid chromatography].

Science.gov (United States)

Zhang, Yanhai; Qibule, Hasi; Jin, Yan; Wang, Jia; Ma, Wenli

2015-03-01

A rapid method for the simultaneous determination of vitamins A, D3 and E in infant formula and adult nutritions has been developed using online two-dimensional liquid chromatography (2D-LC). First of all, C8 and polar embedded C18 columns were chosen as the first and second dimensional column respectively according to hydrophobic-subtraction model, which constituted excellent orthogonal separation system. The detection wavelengths were set at 263 nm for vitamin D3, 296 nm for vitamin E and 325 nm for vitamin A. The purification of vitamin D3 and quantifications of vitamins A and E were completed simultaneously in the first dimensional separation using the left pump of Dual Gradient LC (DGLC) with methanol, acetonitrile and water as mobile phases. The heart-cutting time window of vitamin D3 was confirmed according to the retention time of vitamin D3 in the first dimensional separation. The elute from the first dimensional column (1-D column) which contained vitamin D3 was collected by a 500 µL sample loop and then taken into the second dimensional column (2-D column) by the right pump of DGLC with methanol, acetonitrile and water as mobile phases. The quantification of vitamin D3 was performed in the second dimensional separation with vitamin D2 as internal standard. At last, this method was applied for the analysis of the three vitamins in milk powder, cheese and yogurt. The injected sample solution with no further purification was pre-treated by hot-saponification using 1. 25 kg/L KOH solution and extracted by petroleum ether solvent. The recoveries of vitamin D3 spiked in all samples were 75.50%-85.00%. There was no statistically significant difference for the results between this method and standard method through t-test. The results indicate that vitamins A, D3 and E in infant formula and adult fortified dairy can be determined rapidly and accurately with this method.

Initial Experience of Tomosynthesis-Guided Vacuum-Assisted Biopsies of Tomosynthesis-Detected (2D Mammography and Ultrasound Occult) Architectural Distortions.

Science.gov (United States)

Patel, Bhavika K; Covington, Matthew; Pizzitola, Victor J; Lorans, Roxanne; Giurescu, Marina; Eversman, William; Lewin, John

2018-03-23

As experience and aptitude in digital breast tomosynthesis (DBT) have increased, radiologists are seeing more areas of architectural distortion (AD) on DBT images compared with standard 2D mammograms. The purpose of this study is to report our experience using tomosynthesis-guided vacuum-assisted biopsies (VABs) for ADs that were occult at 2D mammography and ultrasound and to analyze the positive predictive value for malignancy. We performed a retrospective review of 34 DBT-detected ADs that were occult at mammography and ultrasound. We found a positive predictive value of 26% (nine malignancies in 34 lesions). Eight of the malignancies were invasive and one was ductal carcinoma in situ. The invasive cancers were grade 1 (4/8; 50%), grade 2 (2/8; 25%), or grade 3 (1/8; 13%); information about one invasive cancer was not available. The mean size of the invasive cancers at pathologic examination was 7.5 mm (range, 6-30 mm). Tomosynthesis-guided VAB is a feasible method to sample ADs that are occult at 2D mammography and ultrasound. Tomosynthesis-guided VAB is a minimally invasive method that detected a significant number of carcinomas, most of which were grade 1 cancers. Further studies are needed.

On final states of two-dimensional decaying turbulence

NARCIS (Netherlands)

Yin, Z.

2004-01-01

Numerical and analytical studies of final states of two-dimensional (2D) decaying turbulence are carried out. The first part of this work is trying to give a definition for final states of 2D decaying turbulence. The functional relation of ¿-¿, which is frequently adopted as the characterization of

Sci-Thur AM: YIS – 03: Combining sagittally-reconstructed 3D and live-2D ultrasound for high-dose-rate prostate brachytherapy needle segmentation

Energy Technology Data Exchange (ETDEWEB)

Hrinivich, Thomas; Hoover, Douglas; Surry, Kathleen; Edirisinghe, Chandima; D’Souza, David; Fenster, Aaron; Wong, Eugene [University of Western Ontario, London Regional Cancer Program/LHSC, London Regional Cancer Program/LHSC, Robarts Research Institute, London Regional Cancer Program/LHSC, Robarts Research Institute, University of Western Ontario (Canada)

2016-08-15

Ultrasound-guided high-dose-rate prostate brachytherapy (HDR-BT) needle segmentation is performed clinically using live-2D sagittal images. Organ segmentation is then performed using axial images, introducing a source of geometric uncertainty. Sagittally-reconstructed 3D (SR3D) ultrasound enables both needle and organ segmentation, but suffers from shadow artifacts. We present a needle segmentation technique augmenting SR3D with live-2D sagittal images using mechanical probe tracking to mitigate image artifacts and compare it to the clinical standard. Seven prostate cancer patients underwent TRUS-guided HDR-BT during which the clinical and proposed segmentation techniques were completed in parallel using dual ultrasound video outputs. Calibrated needle end-length measurements were used to calculate insertion depth errors (IDEs), and the dosimetric impact of IDEs was evaluated by perturbing clinical treatment plan source positions. The proposed technique provided smaller IDEs than the clinical approach, with mean±SD of −0.3±2.2 mm and −0.5±3.7mm respectively. The proposed and clinical techniques resulted in 84% and 43% of needles with IDEs within ±3mm, and IDE ranges across all needles of [−7.7mm, 5.9mm] and [−9.3mm, 7.7mm] respectively. The proposed and clinical IDEs lead to mean±SD changes in the volume of the prostate receiving the prescription dose of −0.6±0.9% and −2.0±5.3% respectively. The proposed technique provides improved HDR-BT needle segmentation accuracy over the clinical technique leading to decreased dosimetric uncertainty by eliminating the axial-to-sagittal registration, and mitigates the effect of shadow artifacts by incorporating mechanically registered live-2D sagittal images.

Syntheses, crystal structures and luminescent properties of two new 1D d 1 coordination polymers constructed from 2,2'-bibenzimidazole and 1,4-benzenedicarboxylate

International Nuclear Information System (INIS)

Wen Lili; Li Yizhi; Dang Dongbin; Tian Zhengfang; Ni Zhaoping; Meng Qingjin

2005-01-01

Two novel interesting d 1 metal coordination polymers, [Zn(H 2 bibzim)(BDC)] n (1) and [Cd(H 2 bibzim)(BDC)] n (2) [H 2 bibzim=2,2'-bibenzimidazole, BDC=1,4-benzenedicarboxylate] have been synthesized under solvothermal conditions and structurally characterized. Both 1 and 2 are constructed from infinite neutral zigzag-like one-dimensional (1D) chains. The π-π interactions and interchain hydrogen-bonding interactions further extend the 1D arrangement to generate a 3D supramolecular architecture for 1 and 2. Both complexes have high thermal stability and display strong blue fluorescent emissions in the solid state upon photo-excitation at 365 nm at room temperature. They are the first two examples that 2,2'-bibenzimidazole has been introduced into the d 1 coordination polymeric framework

Parameters of two-dimensional perineal ultrasonography for evaluation of urinary incontinence after Radical Prostatectomy

Directory of Open Access Journals (Sweden)

Danilo Souza Lima da Costa Cruz

2014-10-01

Full Text Available Introduction Urinary incontinence remains a major concern for patients undergoing radical prostatectomy. Its prevalence can reach 20% in the late postoperative period. Materials and Methods This clinical study investigated the differences of a dynamic evaluation of the urethra and pelvic floor contraction using perineal ultrasound in men without prostate surgery and in men submitted to radical prostatectomy with and without stress urinary incontinence. Ninety two male patients were included, which 70% of them underwent radical prostatectomy (RP for more than one year. Thirty one men with clinically post prostatectomy incontinence were compared by two-dimensional (2D perineal ultrasound to 34 patients without post prostatectomy incontinence and to 27 men without surgery in two centers in Brazil. Results Our results showed that the continent group presented the urethral angle at rest significantly lower than the prostate group (p = 0.0002. We also observed that the incontinent group showed the displacement of the anterior bladder neck during contraction significantly lower than the continent group (p = 0.008. Conclusions We found that the continent group presented the urethral angle at rest significantly lower than the prostate group. The incontinent group also showed the anterior bladder neck displacement during contraction significantly lower than the continent group. It was more evident when the severe incontinent group and the continent group were compared.

Two-dimensional magnetism in the triangular antiferromagnet NiGa2S4

International Nuclear Information System (INIS)

Nambu, Yusuke

2013-01-01

At sufficiently low temperatures, electron spins in normal magnets generally order into some fashion, for instance, ferromagnetic and antiferromagnetic. Geometrical frustration and/or reduced dimensionality can suppress such conventional orders, and occasionally induce unknown states of matter. This is the case for the two-dimensional (2D) triangular antiferromagnet Ni(Ga 2 S 4 , in which S=1 nickel spins do not order, instead show an exotic magnetism. We found (1) a resonant critical slowing down toward T*=8.5 K followed by a viscous spin liquid behavior, and (2) a spin-size dependent ground state. To elucidate (1), spin dynamics ranging from 10 -13 to 10 0 seconds were quantitatively explored through the experimental techniques such as inelastic neutron scattering, backscattering, neutron spin echo, ac and nonlinear susceptibilities. The finding of (2) is evidenced by impurity effects. Integer spins substituted systems such as zinc and iron ions retain a quadratic temperature dependence of the magnetic specific heat as for the parent compound. However, substitutions of half-odd integer spins, cobalt and manganese ions, eventually induce a distinct behavior, indicating an importance of integer size of spins to stabilize the 2D magnetism realized in NiGa 2 S 4 . The article gives our experimental findings and as well as some relevant theoretical scenarios. (author)

3D thoracoscopic ultrasound volume measurement validation in an ex vivo and in vivo porcine model of lung tumours

International Nuclear Information System (INIS)

Hornblower, V D M; Yu, E; Fenster, A; Battista, J J; Malthaner, R A

2007-01-01

The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial 'tumours' were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the 'tumours' were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the ultrasound images and a manual-radial segmentation technique and these were compared with the known volumes of the agar. In vitro measurements had average accuracy and precision of 4.76% and 1.77%, respectively; in vivo measurements had average accuracy and precision of 8.18% and 1.75%, respectively. The 3D thoracoscopic ultrasound can be used to accurately and reproducibly measure 'tumour' volumes both in vivo and ex vivo

3D thoracoscopic ultrasound volume measurement validation in an ex vivo and in vivo porcine model of lung tumours

Energy Technology Data Exchange (ETDEWEB)

Hornblower, V D M [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Yu, E [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Fenster, A [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Battista, J J [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Malthaner, R A [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada)

2007-01-07

The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial 'tumours' were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the 'tumours' were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the ultrasound images and a manual-radial segmentation technique and these were compared with the known volumes of the agar. In vitro measurements had average accuracy and precision of 4.76% and 1.77%, respectively; in vivo measurements had average accuracy and precision of 8.18% and 1.75%, respectively. The 3D thoracoscopic ultrasound can be used to accurately and reproducibly measure 'tumour' volumes both in vivo and ex vivo.

Two-Dimensional SiO2/VO2 Photonic Crystals with Statically Visible and Dynamically Infrared Modulated for Smart Window Deployment.

Science.gov (United States)

Ke, Yujie; Balin, Igal; Wang, Ning; Lu, Qi; Tok, Alfred Iing Yoong; White, Timothy J; Magdassi, Shlomo; Abdulhalim, Ibrahim; Long, Yi

2016-12-07

Two-dimensional (2D) photonic structures, widely used for generating photonic band gaps (PBG) in a variety of materials, are for the first time integrated with the temperature-dependent phase change of vanadium dioxide (VO 2 ). VO 2 possesses thermochromic properties, whose potential remains unrealized due to an undesirable yellow-brown color. Here, a SiO 2 /VO 2 core/shell 2D photonic crystal is demonstrated to exhibit static visible light tunability and dynamic near-infrared (NIR) modulation. Three-dimensional (3D) finite difference time domain (FDTD) simulations predict that the transmittance can be tuned across the visible spectrum, while maintaining good solar regulation efficiency (ΔT sol = 11.0%) and high solar transmittance (T lum = 49.6%). Experiments show that the color changes of VO 2 films are accompanied by NIR modulation. This work presents a novel way to manipulate VO 2 photonic structures to modulate light transmission as a function of wavelength at different temperatures.

Topology as fluid geometry two-dimensional spaces, volume 2

CERN Document Server

Cannon, James W

2017-01-01

This is the second of a three volume collection devoted to the geometry, topology, and curvature of 2-dimensional spaces. The collection provides a guided tour through a wide range of topics by one of the twentieth century's masters of geometric topology. The books are accessible to college and graduate students and provide perspective and insight to mathematicians at all levels who are interested in geometry and topology. The second volume deals with the topology of 2-dimensional spaces. The attempts encountered in Volume 1 to understand length and area in the plane lead to examples most easily described by the methods of topology (fluid geometry): finite curves of infinite length, 1-dimensional curves of positive area, space-filling curves (Peano curves), 0-dimensional subsets of the plane through which no straight path can pass (Cantor sets), etc. Volume 2 describes such sets. All of the standard topological results about 2-dimensional spaces are then proved, such as the Fundamental Theorem of Algebra (two...

JAC2D: A two-dimensional finite element computer program for the nonlinear quasi-static response of solids with the conjugate gradient method

International Nuclear Information System (INIS)

Biffle, J.H.; Blanford, M.L.

1994-05-01

JAC2D is a two-dimensional finite element program designed to solve quasi-static nonlinear mechanics problems. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. A nonlinear conjugate gradient method is used to solve the equations. The method is implemented in a two-dimensional setting with various methods for accelerating convergence. Sliding interface logic is also implemented. A four-node Lagrangian uniform strain element is used with hourglass stiffness to control the zero-energy modes. This report documents the elastic and isothermal elastic/plastic material model. Other material models, documented elsewhere, are also available. The program is vectorized for efficient performance on Cray computers. Sample problems described are the bending of a thin beam, the rotation of a unit cube, and the pressurization and thermal loading of a hollow sphere

GPU-Based Block-Wise Nonlocal Means Denoising for 3D Ultrasound Images

Directory of Open Access Journals (Sweden)

Liu Li

2013-01-01

Full Text Available Speckle suppression plays an important role in improving ultrasound (US image quality. While lots of algorithms have been proposed for 2D US image denoising with remarkable filtering quality, there is relatively less work done on 3D ultrasound speckle suppression, where the whole volume data rather than just one frame needs to be considered. Then, the most crucial problem with 3D US denoising is that the computational complexity increases tremendously. The nonlocal means (NLM provides an effective method for speckle suppression in US images. In this paper, a programmable graphic-processor-unit- (GPU- based fast NLM filter is proposed for 3D ultrasound speckle reduction. A Gamma distribution noise model, which is able to reliably capture image statistics for Log-compressed ultrasound images, was used for the 3D block-wise NLM filter on basis of Bayesian framework. The most significant aspect of our method was the adopting of powerful data-parallel computing capability of GPU to improve the overall efficiency. Experimental results demonstrate that the proposed method can enormously accelerate the algorithm.

Preoperative 4D CT Localization of Nonlocalizing Parathyroid Adenomas by Ultrasound and SPECT-CT.

Science.gov (United States)

Hinson, Andrew M; Lee, David R; Hobbs, Bradley A; Fitzgerald, Ryan T; Bodenner, Donald L; Stack, Brendan C

2015-11-01

To evaluate 4-dimensional (4D) computed tomography (CT) for the localization of parathyroid adenomas previously considered nonlocalizing on ultrasound and single-photon emission CT with CT scanning (SPECT-CT). To measure radiation exposure associated with 4D-CT and compared it with SPECT-CT. Case series with chart review. University tertiary hospital. Nineteen adults with primary hyperparathyroidism who underwent preoperative 4D CT from November 2013 through July 2014 after nonlocalizing preoperative ultrasound and technetium-99m SPECT-CT scans. Sensitivity, specificity, predictive values, and accuracy of 4D CT were evaluated. Nineteen patients (16 women and 3 men) were included with a mean age of 66 years (range, 39-80 years). Mean preoperative parathyroid hormone level was 108.5 pg/mL (range, 59.3-220.9 pg/mL), and mean weight of the excised gland was 350 mg (range, 83-797 mg). 4D CT sensitivity and specificity for localization to the patient's correct side of the neck were 84.2% and 81.8%, respectively; accuracy was 82.9%. The sensitivity for localizing adenomas to the correct quadrant was 76.5% and 91.5%, respectively; accuracy was 88.2%. 4D CT radiation exposure was significantly less than the radiation associated with SPECT-CT (13.8 vs 18.4 mSv, P = 0.04). 4D CT localizes parathyroid adenomas with relatively high sensitivity and specificity and allows for the localization of some adenomas not observed on other sestamibi-based scans. 4D CT was also associated with less radiation exposure when compared with SPECT-CT based on our study protocol. 4D CT may be considered as first- or second-line imaging for localizing parathyroid adenomas in the setting of primary hyperparathyroidism. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Image Making in Two Dimensional Art; Experiences with Straw and ...

African Journals Online (AJOL)

Image making in art is professionally referred to as bust in Sculpture andPortraiture in Painting. It is an art form executed in three dimensional (3D)and two dimensional (2D) formats respectively. Uncountable materials havebeen used to achieve these forms of art; like clay cement, marble, stone,different metals and, fibre ...

Spin-Dependent Scattering Effects and Dimensional Crossover in a Quasi-Two-Dimensional Disordered Electron System

Institute of Scientific and Technical Information of China (English)

YANG YongHong; WANG YongGang; LIU Mei; WANG Jin

2002-01-01

Two kinds of spin-depcndcnt scattering effects (magnetic-iinpurity and spin-orbit scatterings) axe investi-gated theoretically in a quasi-two-dimensional (quasi-2D) disordered electron system. By making use of the diagrammatictechniques in perturbation theory, we have calculated the dc conductivity and magnetoresistance due to weak-localizationeffects, the analytical expressions of them are obtained as functions of the interlayer hopping energy and the charac-teristic times: elastic, inelastic, magnetic and spin-orbit scattering times. The relevant dimensional crossover behaviorfrom 3D to 2D with decreasing the interlayer coupling is discussed, and the condition for the crossover is shown to bedependent on the aforementioned scattering times. At low temperature there exists a spin-dcpendent-scattering-induccddimensional crossover in this system.

Three-dimensional power Doppler ultrasound in the early assessment of response to concurrent chemo-radiotherapy for advanced cervical cancer.

Science.gov (United States)

Xu, Yan; Zhu, Lijing; Ru, Tong; Wang, Huanhuan; He, Jian; Zhou, Zhengyang; Yang, Xiaofeng

2017-09-01

Background Three-dimensional power Doppler ultrasound (3D-PDU) imaging has been widely applied to the differentiation of benign and malignant cervical lesions; however, its potential value for predicting response to chemo-radiotherapy has not been fully explored. Purpose To investigate the feasibility of 3D-PDU imaging in predicting treatment response in patients receiving concurrent chemo-radiotherapy (CCRT) for advanced cervical cancer. Material and Methods Fifty-two patients with advanced cervical cancer who received CCRT underwent 3D-PDU examinations at four timepoints: pre-therapy (baseline), 1 week and 2 weeks during, as well as immediately post CCRT. Final tumor response was determined by change in tumor size using magnetic resonance imaging (MRI). Cervical tumor volumes and vascular indices were calculated and compared with the clinical outcome. Results Of the 52 patients, 32 patients who completed all four examinations were included in the analyses: 21 were classified as complete response (CR) and 11 as partial response (PR). During the treatment, the CR group showed that 3D vascular indices (VI and VFI) significantly increased at 1 week ( P = 0.028, P = 0.017, respectively) then decreased at 2 weeks and obviously decreased at therapy completion (both P  0.05). Conclusion Prospective longitudinal 3D-PDU imaging may have potentials in monitoring early therapeutic response to CCRT in patients with cervical cancer.

Waterlike anomalies in a two-dimensional core-softened potential

Science.gov (United States)

Bordin, José Rafael; Barbosa, Marcia C.

2018-02-01

We investigate the structural, thermodynamic, and dynamic behavior of a two-dimensional (2D) core-corona system using Langevin dynamics simulations. The particles are modeled by employing a core-softened potential which exhibits waterlike anomalies in three dimensions. In previous studies in a quasi-2D system a new region in the pressure versus temperature phase diagram of structural anomalies was observed. Here we show that for the two-dimensional case two regions in the pressure versus temperature phase diagram with structural, density, and diffusion anomalies are observed. Our findings indicate that, while the anomalous region at lower densities is due the competition between the two length scales in the potential at higher densities, the anomalous region is related to the reentrance of the melting line.

Geometrical aspects of solvable two dimensional models

International Nuclear Information System (INIS)

Tanaka, K.

1989-01-01

It was noted that there is a connection between the non-linear two-dimensional (2D) models and the scalar curvature r, i.e., when r = -2 the equations of motion of the Liouville and sine-Gordon models were obtained. Further, solutions of various classical nonlinear 2D models can be obtained from the condition that the appropriate curvature two form Ω = 0, which suggests that these models are closely related. This relation is explored further in the classical version by obtaining the equations of motion from the evolution equations, the infinite number of conserved quantities, and the common central charge. The Poisson brackets of the solvable 2D models are specified by the Virasoro algebra. 21 refs

Three-dimensional versus two-dimensional vision in laparoscopy

DEFF Research Database (Denmark)

Sørensen, Stine D; Savran, Mona Meral; Konge, Lars

2016-01-01

were cohort size and characteristics, skill trained or operation performed, instrument used, outcome measures, and conclusions. Two independent authors performed the search and data extraction. RESULTS: Three hundred and forty articles were screened for eligibility, and 31 RCTs were included...... through a two-dimensional (2D) projection on a monitor, which results in loss of depth perception. To counter this problem, 3D imaging for laparoscopy was developed. A systematic review of the literature was performed to assess the effect of 3D laparoscopy. METHODS: A systematic search of the literature...... in the review. Three trials were carried out in a clinical setting, and 28 trials used a simulated setting. Time was used as an outcome measure in all of the trials, and number of errors was used in 19 out of 31 trials. Twenty-two out of 31 trials (71 %) showed a reduction in performance time, and 12 out of 19...

Graphene and Two-Dimensional Materials for Optoelectronic Applications

Directory of Open Access Journals (Sweden)

Andreas Bablich

2016-03-01

Full Text Available This article reviews optoelectronic devices based on graphene and related two-dimensional (2D materials. The review includes basic considerations of process technology, including demonstrations of 2D heterostructure growth, and comments on the scalability and manufacturability of the growth methods. We then assess the potential of graphene-based transparent conducting electrodes. A major part of the review describes photodetectors based on lateral graphene p-n junctions and Schottky diodes. Finally, the progress in vertical devices made from 2D/3D heterojunctions, as well as all-2D heterostructures is discussed.

Computer vision elastography: speckle adaptive motion estimation for elastography using ultrasound sequences.

Science.gov (United States)

Revell, James; Mirmehdi, Majid; McNally, Donal

2005-06-01

We present the development and validation of an image based speckle tracking methodology, for determining temporal two-dimensional (2-D) axial and lateral displacement and strain fields from ultrasound video streams. We refine a multiple scale region matching approach incorporating novel solutions to known speckle tracking problems. Key contributions include automatic similarity measure selection to adapt to varying speckle density, quantifying trajectory fields, and spatiotemporal elastograms. Results are validated using tissue mimicking phantoms and in vitro data, before applying them to in vivo musculoskeletal ultrasound sequences. The method presented has the potential to improve clinical knowledge of tendon pathology from carpel tunnel syndrome, inflammation from implants, sport injuries, and many others.

SU-F-J-176: Development of a Patient-Specific 3D Couplant Pad for Ultrasound IGRT

Energy Technology Data Exchange (ETDEWEB)

Kim, H; Chang, A [Soonchunhyang University Hospital, Seoul (Korea, Republic of); Ye, S [Seoul National University, Seoul (Korea, Republic of)

2016-06-15

Purpose: to overcome the several issues of ultrasound image-guided radiation therapy (US IGRT) such as probe pressure and optical tracking disability by using a patient-specific three-dimensional couplant pad (CP) fabricated by a patient’s skin mold using a 3D printing technique. Methods: A CP was then fabricated by pouring gelatin solution into a fixed-shape container accommodating the patient skin mold fabricated by a 3D printer. A breast phantom was fabricated with the compound of gelatin and agarose and a phantom study was carried out. From four patients who underwent US IGRT, total 486 ultrasound images with and without a CP were acquired before treatment. Effectiveness of the use of the CP was evaluated. Results: The positioning accuracies in the phantom study were 0.9 ± 0.3 mm and 1.3 ± 0.4 mm with and without the CP in 3D vector amplitude, respectively. In the patient study, the use of CP reduced the mean target shift from 4.7 mm to 3.7 mm in 3D vector amplitude and the one standard deviation from 2.2 mm to 1.7 mm. It also improved the image contrast around the treatment target by 10 %. The centroid offset of the target volume affected from the US scanning coverage and the target deformation due to the excessive probe pressure was decreased from 4.4 mm to 2.9 mm due to the use of CP. Its difference among three different users was statistically significant (p=0.020) without the use of CP but not significantly different (p=0.133) with the use of CP. Conclusion: Our patient-specific 3D CP using a mold by 3D printing technique is a promising strategy for improving tracking accuracy, image quality, and inter-observer variation for ultrasound-based image guided radiotherapy. In addition to its conventional advantage of non-invasiveness, US can be more facilitated in radiotherapy by the developed CP.

SU-F-J-176: Development of a Patient-Specific 3D Couplant Pad for Ultrasound IGRT

International Nuclear Information System (INIS)

Kim, H; Chang, A; Ye, S

2016-01-01

Purpose: to overcome the several issues of ultrasound image-guided radiation therapy (US IGRT) such as probe pressure and optical tracking disability by using a patient-specific three-dimensional couplant pad (CP) fabricated by a patient’s skin mold using a 3D printing technique. Methods: A CP was then fabricated by pouring gelatin solution into a fixed-shape container accommodating the patient skin mold fabricated by a 3D printer. A breast phantom was fabricated with the compound of gelatin and agarose and a phantom study was carried out. From four patients who underwent US IGRT, total 486 ultrasound images with and without a CP were acquired before treatment. Effectiveness of the use of the CP was evaluated. Results: The positioning accuracies in the phantom study were 0.9 ± 0.3 mm and 1.3 ± 0.4 mm with and without the CP in 3D vector amplitude, respectively. In the patient study, the use of CP reduced the mean target shift from 4.7 mm to 3.7 mm in 3D vector amplitude and the one standard deviation from 2.2 mm to 1.7 mm. It also improved the image contrast around the treatment target by 10 %. The centroid offset of the target volume affected from the US scanning coverage and the target deformation due to the excessive probe pressure was decreased from 4.4 mm to 2.9 mm due to the use of CP. Its difference among three different users was statistically significant (p=0.020) without the use of CP but not significantly different (p=0.133) with the use of CP. Conclusion: Our patient-specific 3D CP using a mold by 3D printing technique is a promising strategy for improving tracking accuracy, image quality, and inter-observer variation for ultrasound-based image guided radiotherapy. In addition to its conventional advantage of non-invasiveness, US can be more facilitated in radiotherapy by the developed CP.

Exciton Migration and Amplified Quenching on Two-Dimensional Metal–Organic Layers

Energy Technology Data Exchange (ETDEWEB)

Cao, Lingyun; Lin, Zekai; Shi, Wenjie; Wang, Zi; Zhang, Cankun; Hu, Xuefu; Wang, Cheng; Lin, Wenbin (UC); (Xiamen)

2017-05-10

The dimensionality dependency of resonance energy transfer is of great interest due to its importance in understanding energy transfer on cell membranes and in low-dimension nanostructures. Light harvesting two-dimensional metal–organic layers (2D-MOLs) and three-dimensional metal–organic frameworks (3D-MOFs) provide comparative models to study such dimensionality dependence with molecular accuracy. Here we report the construction of 2D-MOLs and 3D-MOFs from a donor ligand 4,4',4''-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tribenzoate (BTE) and a doped acceptor ligand 3,3',3''-nitro-4,4',4''-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tribenzoate (BTE-NO2). These 2D-MOLs and 3D-MOFs are connected by similar hafnium clusters, with key differences in the topology and dimensionality of the metal–ligand connection. Energy transfer from donors to acceptors through the 2D-MOL or 3D-MOF skeletons is revealed by measuring and modeling the fluorescence quenching of the donors. We found that energy transfer in 3D-MOFs is more efficient than that in 2D-MOLs, but excitons on 2D-MOLs are more accessible to external quenchers as compared with those in 3D-MOFs. These results not only provide support to theoretical analysis of energy transfer in low dimensions, but also present opportunities to use efficient exciton migration in 2D materials for light-harvesting and fluorescence sensing.

Value of Quantitative Three-dimensional Doppler Ultrasound in the Differentiation of Benign and Malignant Thyroid Nodules.

Science.gov (United States)

Li, Wen-Bo; Zhang, Bo; Jiang, Yu-Xin; Zhu, Qing-Li; Zhang, Qing; Sun, Jian

2015-06-01

To investigate the role of quantitative three-dimensional (3D) power Doppler ultrasound in differentiating malignant and benign thyroid nodule. A total of 92 lesions in 86 patients were preoperatively examined using 3D power Doppler ultrasound. The Virtual Organ Computer-aided Analysis(VOCAL)-imaging program was used to analyze the stored volume ultrasound. The differences in the mean gray value (MG), vascularization index (VI), flow index(FI), and vascularization flow index (VFI) were compared between benign and malignant lesions. The MG of the malignant thyroid nodules was significantly lower than that of the benign ones (28.27±7.21 vs. 32.89±8.73,P=0.007). The benign nodules had significantly higher VI,FI,and VFI than the malignant nodules [VI:(40.43±26.55)% vs. (26.87±23.06)%,P=0.011;FI:41.03±7.19 vs. 37.51±7.17,P=0.022;VFI:18.23±14.60 vs. 11.47±12.47, P=0.009]. Also,76.5% (39/51) of the malignant nodules and 92.7% (38/41) of the benign nodules had higher VIs in the shell of the lesion than that of the whole lesion,and 80.4%(41/51) of the malignant nodules and 95.1% (39/41) of the benign nodules had higher FIs in the shell of the lesion than that of the whole lesion. Quantitative 3D power Doppler ultrasound provides a useful tool in distinguishing benign and malignant thyroid nodules. The malignant thyroid nodules have lower echoes than the benign nodules, wherese the benign nodules have larger blood flow than the malignant nodules.

Femtosecond X-ray diffraction from two-dimensional protein crystals

Directory of Open Access Journals (Sweden)

Matthias Frank

2014-03-01

Full Text Available X-ray diffraction patterns from two-dimensional (2-D protein crystals obtained using femtosecond X-ray pulses from an X-ray free-electron laser (XFEL are presented. To date, it has not been possible to acquire transmission X-ray diffraction patterns from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permit a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy approach at the Linac Coherent Light Source, Bragg diffraction was acquired to better than 8.5 Å resolution for two different 2-D protein crystal samples each less than 10 nm thick and maintained at room temperature. These proof-of-principle results show promise for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals.

Sub-Nanometer Channels Embedded in Two-Dimensional Materials

KAUST Repository

Han, Yimo; Li, Ming-yang; Jung, Gang-Seob; Marsalis, Mark A.; Qin, Zhao; Buehler, Markus J.; Li, Lain-Jong; Muller, David A.

2017-01-01

Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically-thin p-n junctions2

Driving performance of a two-dimensional homopolar linear DC motor

Energy Technology Data Exchange (ETDEWEB)

Wang, Y.; Yamaguchi, M.; Kano, Y. [Tokyo University of Agriculture and Technology, Tokyo (Japan)

1998-05-01

This paper presents a novel two-dimensional homopolar linear de motor (LDM) which can realize two-dimensional (2-D) motion. For position control purposes, two kinds of position detecting methods are proposed. The position in one position is detected by means of a capacitive sensor which makes the output of the sensor partially immune to the variation of the gap between electrodes. The position in the other direction is achieved by exploiting the position dependent property of the driving coil inductance, instead of using an independent sensor. The position control is implemented on the motor and 2-D tracking performance is analyzed. Experiments show that the motor demonstrates satisfactory driving performance, 2-D tracking error being within 5.5% when the angular frequency of reference signal is 3.14 rad./s. 7 refs., 17 figs., 2 tabs.

Sub-nanometre channels embedded in two-dimensional materials

KAUST Repository

Han, Yimo

2017-12-04

Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically thin p–n junctions2,3,4,5,6,7,8, metal–semiconductor contacts9,10,11, and metal–insulator barriers12,13,14 have been demonstrated. Although 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions is also necessary. Here, we report the direct synthesis of sub-nanometre-wide one-dimensional (1D) MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalysed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Using molecular dynamics simulations, we have identified other combinations of 2D materials where 1D channels can also be formed. The electronic band structure of these 1D channels offers the promise of carrier confinement in a direct-gap material and the charge separation needed to access the ultimate length scales necessary for future electronic applications.

Quantitative analysis of valsartan by two-dimensional liquid chromatography (2D-HPLC) and its application in a bioequivalence study in Chinese volunteers
.

Science.gov (United States)

Zhang, Min; Deng, Yang; Cai, Hua-Lin; Fang, Ping-Fei; Yan, Miao; Zhang, Bi-Kui; Wu, Yan-Qin

2017-04-01

To develop a sensitive, two-dimensional liquid chromatography (2D-LC) method for determination of valsartan, applied to investigate bioequivalence of two valsartan tablets in Chinese volunteers under fasting condition. A full automatic 2D-HPLC system was used to quantify valsartan in human plasma. The analytes were extracted by protein precipitation, using telmisartan as internal standard. The analytical method was applied in a randomized, crossover bioequivalence study of valsartan tablets; the study enrolled 18 Chinese volunteers (12 were men and 6 were women). The subjects received a single 160-mg dose of test or reference preparation with 7-days of washout under fasting state. Plasma samples were collected, pharmacokinetic parameters were obtained and the bioequivalence was evaluated. The calibration range was 9.2 - 4213.8 ng×mL-1. Inter- and intraprecision was less than 7.0%, and accuracies ranged from 99.5 to 103.8%. The extraction recovery for valsartan varied between 89.3 and 97.8%, and the stability in all conditions was excellent. The 90% CI of AUC0→36h and Cmax were 96.5 - 109.4% and 94.2 - 108.6%, respectively. The relative bioavailability was 103.9 ± 15.7%. No gender difference was observed in pharmacokinetic parameters. A sensitive 2D-HPLC method was established for the estimation of valsartan in human plasma and successfully applied in a bioequivalence study of valsartan, which suggests that these two formulations can be assumed to be bioequivalent.
.

Two-dimensional versus three-dimensional treatment planning of tangential breast irradiation

International Nuclear Information System (INIS)

Damen, E.M.F.; Bruinvis, I.A.D.; Mijnheer, B.J.

1995-01-01

Purpose: Full three-dimensional (3-D) treatment planning requires 3-D patient contours and density information, derived either from CT scanning or from other 3-D contouring methods. These contouring techniques are time consuming, and are often not available or cannot be used. Two-dimensional (2-D) treatment planning can be performed using only a few patient contours, made with much simpler techniques, in combination with simulator images for estimating the lung position. In order to investigate the need for full 3-D planning, we compared the performance of both a 2-D and a 3-D planning system in calculating absolute dose values and relative dose distributions in tangential breast irradiation. Methods: Two breast-shaped phantoms were used in this study. The first phantom consists of a polyethylene mould, filled with water and cork to mimic the lung. An ionization chamber can be inserted in the phantom at fixed positions. The second phantom is made of 25 transverse slices of polystyrene and cork, made with a computerized milling machine from CT information. In this phantom, films can be inserted in three sagittal planes. Both phantoms have been irradiated with two tangential 8 MV photon beams. The measured dose distribution has been compared with the dose distribution predicted by the two planning systems. Results: In the central plane, the 3-D planning system predicts the absolute dose with an accuracy of 0.5 - 4%. The dose at the isocentre of the beams agrees within 0.5% with the measured dose. The 2-D system predicts the dose with an accuracy of 0.9 - 3%. The dose calculated at the isocentre is 2.6% higher than the measured dose, because missing lateral scatter is not taken into account in this planning system. In off-axis planes, the calculated absolute dose agrees with the measured dose within 4% for the 2-D system and within 6% for the 3-D system. However, the relative dose distribution is predicted better by the 3-D planning system. Conclusions: This study

Hydrothermal synthesis of zinc(II)-phosphonate coordination polymers with different dimensionality (0D, 2D, 3D) and dimensionality change in the solid phase (0D→3D) induced by temperature

Energy Technology Data Exchange (ETDEWEB)

Fernández-Zapico, Eva; Montejo-Bernardo, Jose; Fernández-González, Alfonso; García, José R., E-mail: jrgm@uniovi.es; García-Granda, Santiago

2015-05-15

Three new zinc(II) coordination polymers, [Zn(HO{sub 3}PCH{sub 2}CH{sub 2}COO)(C{sub 12}H{sub 8}N{sub 2})(H{sub 2}O)] (1), [Zn{sub 3}(O{sub 3}PCH{sub 2}CH{sub 2}COO){sub 2}(C{sub 12}H{sub 8}N{sub 2})](H{sub 2}O){sub 3.40} (2) and [Zn{sub 5}(HO{sub 3}PCH{sub 2}CH{sub 2}COO){sub 2}(O{sub 3}PCH{sub 2}CH{sub 2}COO){sub 2}(C{sub 12}H{sub 8}N{sub 2}){sub 4}](H{sub 2}O){sub 0.32} (3), with different structural dimensionality (0D, 2D and 3D, respectively) have been prepared by hydrothermal synthesis, and their structures were determined by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system (P2{sub 1}/c) forming discrete dimeric units bonded through H-bonds, while compounds 2 and 3 crystallize in the triclinic (P−1) and the monoclinic (C2/c) systems, respectively. Compound 3, showing three different coordination numbers (4, 5 and 6) for the zinc atoms, has also been obtained by thermal treatment of 1 (probed by high-temperature XRPD experiments). The crystalline features of these compounds, related to the coordination environments for the zinc atoms in each structure, provoke the increase of the relative fluorescence for 2 and 3, compared to the free phenanthroline. Thermal analysis (TG and DSC) and XPS studies have been also carried out for all compounds. - Graphical abstract: Three new coordination compounds of zinc with 2-carboxyethylphosphonic acid (H{sub 2}PPA) and phenanthroline have been obtained by hydrothermal synthesis. The crystalline structure depends on the different coordination environments of the zinc atoms (see two comparative Zn{sub 6}-moieties). The influence of the different coordination modes of H{sub 2}PPA with the central atom in all structures have been studied, being found new coordination modes for this ligand. Several compounds show a significant increase in relative fluorescence with respect to the free phenanthroline. - Highlights: • Compounds have been obtained modifying the reaction time and the rate of

The sequence d(CGGCGGCCGC) self-assembles into a two dimensional rhombic DNA lattice

International Nuclear Information System (INIS)

Venkadesh, S.; Mandal, P.K.; Gautham, N.

2011-01-01

Highlights: → This is the first crystal structure of a four-way junction with sticky ends. → Four junction structures bind to each other and form a rhombic cavity. → Each rhombus binds to others to form 'infinite' 2D tiles. → This is an example of bottom-up fabrication of a DNA nano-lattice. -- Abstract: We report here the crystal structure of the partially self-complementary decameric sequence d(CGGCGGCCGC), which self assembles to form a four-way junction with sticky ends. Each junction binds to four others through Watson-Crick base pairing at the sticky ends to form a rhombic structure. The rhombuses bind to each other and form two dimensional tiles. The tiles stack to form the crystal. The crystal diffracted in the space group P1 to a resolution of 2.5 A. The junction has the anti-parallel stacked-X conformation like other junction structures, though the formation of the rhombic net noticeably alters the details of the junction geometry.

Matched-pair analyses of resting and dynamic morphology between Monarc and TVT-O procedures by ultrasound.

Science.gov (United States)

Yang, Jenn-Ming; Yang, Shwu-Huey; Huang, Wen-Chen; Tzeng, Chii-Ruey

2013-07-01

To determine morphologic differences between Monarc and TVT-O procedures in axial and coronal planes by three- and four-dimensional (3D and 4D) ultrasound. Retrospective chart audits and ultrasound analyses were conducted on 128 women who had undergone either Monarc or TVT-O procedures for urodynamic stress incontinence. Thirty matched pairs of the two successful procedures were randomly selected and compared. Matched variables were age, parity, body mass index, cesarean status, menopausal status, and primary surgeries. Six-month postoperative 3D and 4D ultrasound results obtained at rest, on straining, and during coughing in these 60 women were analyzed. Assessed ultrasound parameters included the axial tape urethral distance (aTUD), axial central urethral echolucent area (aUCEA), axial tape angle (aTA), and coronal tape angle (cTA), all of which were measured at three equidistant points along the tapes. Paired t-tests were used to compare differences in ultrasound parameters between women after the two procedures and a P value TVT-O procedures. There were no significant differences in other resting ultrasound parameters between these two procedures. Additionally, after both procedures women had comparable straining and coughing ultrasound manifestations as well as respective dynamic changes. Despite flatter resting tape angulations in women following Monarc procedures, both Monarc and TVT-O tapes had equivalent dynamic patterns and changes assessed by 4D ultrasound. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

How 3D immersive visualization is changing medical diagnostics

Science.gov (United States)

Koning, Anton H. J.

2011-03-01

Originally the only way to look inside the human body without opening it up was by means of two dimensional (2D) images obtained using X-ray equipment. The fact that human anatomy is inherently three dimensional leads to ambiguities in interpretation and problems of occlusion. Three dimensional (3D) imaging modalities such as CT, MRI and 3D ultrasound remove these drawbacks and are now part of routine medical care. While most hospitals 'have gone digital', meaning that the images are no longer printed on film, they are still being viewed on 2D screens. However, this way valuable depth information is lost, and some interactions become unnecessarily complex or even unfeasible. Using a virtual reality (VR) system to present volumetric data means that depth information is presented to the viewer and 3D interaction is made possible. At the Erasmus MC we have developed V-Scope, an immersive volume visualization system for visualizing a variety of (bio-)medical volumetric datasets, ranging from 3D ultrasound, via CT and MRI, to confocal microscopy, OPT and 3D electron-microscopy data. In this talk we will address the advantages of such a system for both medical diagnostics as well as for (bio)medical research.

Optical Studies of Excitonic Effects at Two-Dimensional Nanostructure Interfaces

Science.gov (United States)

Ajayi, Obafunso Ademilolu

Atomically thin two-dimensional nanomaterials such as graphene and transition metal dichalcogenides (TMDCs) have seen a rapid growth of exploration since the isolation of monolayer graphene. These materials provide a rich field of study for physics and optoelectronics applications. Many applications seek to combine a two dimensional (2D) material with another nanomaterial, either another two dimensional material or a zero (0D) or one dimensional (1D) material. The work in this thesis explores the consequences of these interactions from 0D to 2D. We begin in Chapter 2 with a study of energy transfer at 0D-2D interfaces with quantum dots and graphene. In our work we seek to maximize the rate of energy transfer by reducing the distance between the materials. We observe an interplay with the distance-dependence and surface effects from our halogen terminated quantum dots that affect our observed energy transfer. In Chapter 3 we study supercapacitance in composite graphene oxide-carbon nanotube electrodes. At this 2D-1D interface we observe a compounding effect between graphene oxide and carbon nanotubes. Carbon nanotubes increase the accessible surface area of the supercapacitors and improve conductivity by forming a conductive pathway through electrodes. In Chapter 4 we investigate effective means of improving sample quality in TMDCs and discover the importance of the monolayer interface. We observe a drastic improvement in photoluminescence when encapsulating our TMDCs with Boron Nitride. We measure spectral linewidths approaching the intrinsic limit due to this 2D-2D interface. We also effectively reduce excess charge and thus the trion-exciton ratio in our samples through substrate surface passivation. In Chapter 5 we briefly discuss our investigations on chemical doping, heterostructures and interlayer decoupling in ReS2. We observe an increase in intensity for p-doped MoS2 samples. We investigated the charge transfer exciton previously identified in

Localization of liver tumors in freehand 3D laparoscopic ultrasound

Science.gov (United States)

Shahin, O.; Martens, V.; Besirevic, A.; Kleemann, M.; Schlaefer, A.

2012-02-01

The aim of minimally invasive laparoscopic liver interventions is to completely resect or ablate tumors while minimizing the trauma caused by the operation. However, restrictions such as limited field of view and reduced depth perception can hinder the surgeon's capabilities to precisely localize the tumor. Typically, preoperative data is acquired to find the tumor(s) and plan the surgery. Nevertheless, determining the precise position of the tumor is required, not only before but also during the operation. The standard use of ultrasound in hepatic surgery is to explore the liver and identify tumors. Meanwhile, the surgeon mentally builds a 3D context to localize tumors. This work aims to upgrade the use of ultrasound in laparoscopic liver surgery. We propose an approach to segment and localize tumors intra-operatively in 3D ultrasound. We reconstruct a 3D laparoscopic ultrasound volume containing a tumor. The 3D image is then preprocessed and semi-automatically segmented using a level set algorithm. During the surgery, for each subsequent reconstructed volume, a fast update of the tumor position is accomplished via registration using the previously segmented and localized tumor as a prior knowledge. The approach was tested on a liver phantom with artificial tumors. The tumors were localized in approximately two seconds with a mean error of less than 0.5 mm. The strengths of this technique are that it can be performed intra-operatively, it helps the surgeon to accurately determine the location, shape and volume of the tumor, and it is repeatable throughout the operation.

Linkage analysis by two-dimensional DNA typing

NARCIS (Netherlands)

te Meerman, G J; Mullaart, E; Meulen ,van der Martin; den Daas, J H; Morolli, B; Uitterlinden, A G; Vijg, J

1993-01-01

In two-dimensional (2-D) DNA typing, genomic DNA fragments are separated, first according to size by electrophoresis in a neutral polyacrylamide gel and second according to sequence by denaturing gradient gel electrophoresis, followed by hybridization analysis using micro- and minisatellite core

Sub-Nanometer Channels Embedded in Two-Dimensional Materials

KAUST Repository

Han, Yimo

2017-07-31

Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically-thin p-n junctions2-7, metal-semiconductor contacts8-10, and metal-insulator barriers11-13 have been demonstrated. While 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions are also necessary. Although external one-dimensional (1D) carbon nanotubes14 can be used to locally gate 2D materials, this adds a non-trivial third dimension, complicating device integration and flexibility. Here, we report the direct synthesis of sub-nanometer 1D MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalyzed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Molecular dynamics (MD) simulations have identified other combinations of 2D materials that could form 1D channels. Density function theory (DFT) calculation predicts these 1D channels display type II band alignment needed for carrier confinement and charge separation to access the ultimate length scales necessary for future electronic applications.

Twelve inequivalent Dirac cones in two-dimensional ${\mathrm{ZrB}}_{\mathrm{<span\; class="hlt">2</span>}}$

Energy Technology Data Exchange (ETDEWEB)

Lopez-Bezanilla, Alejandro

2018-01-01

Theoretical evidence of the existence of 12 inequivalent Dirac cones at the vicinity of the Fermi energy in monolayered ZrB2 is presented. Two-dimensional ZrB2 is a mechanically stable d- and p-orbital compound exhibiting a unique electronic structure with two Dirac cones out of high-symmetry points in the irreducible Brillouin zone with a small electron-pocket compensation. First-principles calculations demonstrate that while one of the cones is insensitive to lattice expansion, the second cone vanishes for small perturbation of the vertical Zr position. Internal symmetry breaking with external physical stimuli, along with the relativistic effect of spin-orbit coupling, is able to remove selectively the Dirac cones. A rational explanation in terms of d- and p-orbital mixing is provided to elucidate the origin of the infrequent Dirac cones in a flat structure. The versatility of transition-metal d orbitals combined with the honeycomb lattice provided by the B atoms yields particular features in a two-dimensional material.

Two-dimensional grating guided-mode resonance tunable filter.

Science.gov (United States)

Kuo, Wen-Kai; Hsu, Che-Jung

2017-11-27

A two-dimensional (2D) grating guided-mode resonance (GMR) tunable filter is experimentally demonstrated using a low-cost two-step nanoimprinting technology with a one-dimensional (1D) grating polydimethylsiloxane mold. For the first nanoimprinting, we precisely control the UV LED irradiation dosage and demold the device when the UV glue is partially cured and the 1D grating mold is then rotated by three different angles, 30°, 60°, and 90°, for the second nanoimprinting to obtain 2D grating structures with different crossing angles. A high-refractive-index film ZnO is then coated on the surface of the grating structure to form the GMR filter devices. The simulation and experimental results demonstrate that the passband central wavelength of the filter can be tuned by rotating the device to change azimuth angle of the incident light. We compare these three 2D GMR filters with differential crossing angles and find that the filter device with a crossing angle of 60° exhibits the best performance. The tunable range of its central wavelength is 668-742 nm when the azimuth angle varies from 30° to 90°.

Two-dimensional electronic spectroscopy with birefringent wedges

Energy Technology Data Exchange (ETDEWEB)

Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

2014-12-15

We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

Effect of malaria on placental volume measured using three-dimensional ultrasound: a pilot study

Directory of Open Access Journals (Sweden)

Rijken Marcus J

2012-01-01

Full Text Available Abstract Background The presence of malaria parasites and histopathological changes in the placenta are associated with a reduction in birth weight, principally due to intrauterine growth restriction. The aim of this study was to examine the feasibility of studying early pregnancy placental volumes using three-dimensional (3D ultrasound in a malaria endemic area, as a small volume in the second trimester may be an indicator of intra-uterine growth restriction and placental insufficiency. Methods Placenta volumes were acquired using a portable ultrasound machine and a 3D ultrasound transducer and estimated using the Virtual Organ Computer-aided AnaLysis (VOCAL image analysis software package. Intra-observer reliability and limits of agreement of the placenta volume measurements were calculated. Polynomial regression models for the mean and standard deviation as a function of gestational age for the placental volumes of uninfected women were created and tested. Based on these equations each measurement was converted into a z -score. The z-scores of the placental volumes of malaria infected and uninfected women were then compared. Results Eighty-four women (uninfected = 65; infected = 19 with a posterior placenta delivered congenitally normal, live born, single babies. The mean placental volumes in the uninfected women were modeled to fit 5th, 10th, 50th, 90th and 95th centiles for 14-24 weeks' gestation. Most placenta volumes in the infected women were below the 50th centile for gestational age; most of those with Plasmodium falciparum were below the 10th centile. The 95% intra-observer limits of agreement for first and second measurements were ± 37.0 mL and ± 25.4 mL at 30 degrees and 15 degrees rotation respectively. Conclusion The new technique of 3D ultrasound volumetry of the placenta may be useful to improve our understanding of the pathophysiological constraints on foetal growth caused by malaria infection in early pregnancy.

Correspondence optimization in 2D standardized carotid wall thickness map by description length minimization: A tool for increasing reproducibility of 3D ultrasound-based measurements.

Science.gov (United States)

Chen, Yimin; Chiu, Bernard

2016-12-01

The previously described 2D standardized vessel-wall-plus-plaque thickness (VWT) maps constructed from 3D ultrasound vessel wall measurements using an arc-length (AL) scaling approach adjusted the geometric variability of carotid arteries and has allowed for the comparisons of VWT distributions in longitudinal and cross-sectional studies. However, this mapping technique did not optimize point correspondence of the carotid arteries investigated. The potential misalignment may lead to errors in point-wise VWT comparisons. In this paper, we developed and validated an algorithm based on steepest description length (DL) descent to optimize the point correspondence implied by the 2D VWT maps. The previously described AL approach was applied to obtain initial 2D maps for a group of carotid arteries. The 2D maps were reparameterized based on an iterative steepest DL descent approach, which consists of the following two steps. First, landmarks established by resampling the 2D maps were aligned using the Procrustes algorithm. Then, the gradient of the DL with respect to horizontal and vertical reparameterizations of each landmark on the 2D maps was computed, and the 2D maps were subsequently deformed in the direction of the steepest descent of DL. These two steps were repeated until convergence. The quality of the correspondence was evaluated in a phantom study and an in vivo study involving ten carotid arteries enrolled in a 3D ultrasound interscan variability study. The correspondence quality was evaluated in terms of the compactness and generalization ability of the statistical shape model built based on the established point correspondence in both studies. In the in vivo study, the effect of the proposed algorithm on interscan variability of VWT measurements was evaluated by comparing the percentage of landmarks with statistically significant VWT-change before and after point correspondence optimization. The statistical shape model constructed with optimized

Dynamics of vortex interactions in two-dimensional flows

DEFF Research Database (Denmark)

Juul Rasmussen, J.; Nielsen, A.H.; Naulin, V.

2002-01-01

The dynamics and interaction of like-signed vortex structures in two dimensional flows are investigated by means of direct numerical solutions of the two-dimensional Navier-Stokes equations. Two vortices with distributed vorticity merge when their distance relative to their radius, d/R-0l. is below...... a critical value, a(c). Using the Weiss-field, a(c) is estimated for vortex patches. Introducing an effective radius for vortices with distributed vorticity, we find that 3.3 ... is effectively producing small scale structures and the relation to the enstrophy "cascade" in developed 2D turbulence is discussed. The influence of finite viscosity on the merging is also investigated. Additionally, we examine vortex interactions on a finite domain, and discuss the results in connection...

MULTI2D - a computer code for two-dimensional radiation hydrodynamics

Science.gov (United States)

Ramis, R.; Meyer-ter-Vehn, J.; Ramírez, J.

2009-06-01

Simulation of radiation hydrodynamics in two spatial dimensions is developed, having in mind, in particular, target design for indirectly driven inertial confinement energy (IFE) and the interpretation of related experiments. Intense radiation pulses by laser or particle beams heat high-Z target configurations of different geometries and lead to a regime which is optically thick in some regions and optically thin in others. A diffusion description is inadequate in this situation. A new numerical code has been developed which describes hydrodynamics in two spatial dimensions (cylindrical R-Z geometry) and radiation transport along rays in three dimensions with the 4 π solid angle discretized in direction. Matter moves on a non-structured mesh composed of trilateral and quadrilateral elements. Radiation flux of a given direction enters on two (one) sides of a triangle and leaves on the opposite side(s) in proportion to the viewing angles depending on the geometry. This scheme allows to propagate sharply edged beams without ray tracing, though at the price of some lateral diffusion. The algorithm treats correctly both the optically thin and optically thick regimes. A symmetric semi-implicit (SSI) method is used to guarantee numerical stability. Program summaryProgram title: MULTI2D Catalogue identifier: AECV_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECV_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 151 098 No. of bytes in distributed program, including test data, etc.: 889 622 Distribution format: tar.gz Programming language: C Computer: PC (32 bits architecture) Operating system: Linux/Unix RAM: 2 Mbytes Word size: 32 bits Classification: 19.7 External routines: X-window standard library (libX11.so) and corresponding heading files (X11/*.h) are

Novel Au- and Ge-based two-dimensional materials formed through topotactic transitions of AlB2-like structures

Science.gov (United States)

Tsetseris, Leonidas

2016-07-01

The topotactic reaction of a layered compound, for example CaGe2, with HCl solution is a common and facile method to produce two-dimensional (2D) materials. In this work we demonstrate with first-principles calculations that this technique can potentially lead to a whole new family of 2D materials starting from three-dimensional crystals with AlB2-like structures. As representative cases, we show here that the de-intercalation of Sc and Ca atoms from ScAuGe and Ca2AuGe3 crystals is strongly exothermic and produces the stable 2D monolayers AuGeH and AuGe3H3, respectively. Remarkably, both metals (AuGeH) and semiconductors (AuGe3H3) can be prepared by this method. Based on the broad availability of AlB2-like structures with varying stoichiometries, there are several possibilities to prepare novel functional 2D materials with suitable topotactic transitions.

Novel solution conformation of DNA observed in d(GAATTCGAATTC) by two-dimensional NMR spectroscopy

International Nuclear Information System (INIS)

Chary, K.V.R.; Hosur, R.V.; Govil, G.; Zu-kun, T.; Miles, H.T.

1987-01-01

Resonance assignments of nonexchangeable base and sugar protons of the self-complementary dodecanucleotide d(GAATTCGAATTC) have been obtained by using the two-dimensional Fourier transform NMR methods correlated spectroscopy and nuclear Overhauser effect spectroscopy. Conformational details about the sugar pucker, the glycosidic dihedral angle, and the overall secondary structure of the molecule has been derived from the relative intensities of cross peaks in the two-dimensional NMR spectra in aqueous solution. It is observed that d(GAATTCGAATTC) assumes a novel double-helical structure. The solution conformations of the two complementary strands are identical, unlike those observed in a related sequence in the solid state. Most of the five-membered sugar rings adopt an unusual O1'-endo geometry. All the glycosidic dihedral angles are in the anti domain. The AATT segments A2-T5 and A8-T11 show better stacking compared to the rest of the molecule. These features fit into a right-handed DNA model for the above two segments, with the sugar geometries different from the conventional ones. There are important structural variations in the central TCG portion, which is known to show preferences for DNase I activity, and between G1-A2 and G7-A8, which are cleavage points in the EcoRI recognition sequence. The sugar puckers for G1 and G7 are significantly different from the rest of the molecule. Further, in the three segments mentioned above, the sugar phosphate geometry is such that the distances between protons on adjacent nucleotides are much larger than those expected for a right-handed DNA. The authors suggest that such crevices in the DNA structure may act as hot points in initiation of protein recognition

On the presence of lower dimensional confinement mechanisms in 4d SU2 lattice gauge theory

International Nuclear Information System (INIS)

Hari Dass, N.D.

1983-11-01

The presence of an essentially two-dimensional confinement mechanism in 4d SU 2 gauge theory has been conjectured. The authors present an explicit realization of this conjecture valid up to β = 1.8 based on variational investigations of lattice gauge theories. (Auth.)

A novel educational tool for teaching ocular ultrasound

Directory of Open Access Journals (Sweden)

Mustafa MS

2011-06-01

Full Text Available MS Mustafa1, J Montgomery2, HR Atta11Department of Ophthalmology, Aberdeen Royal Infirmary, UK; 2Medi-CAL, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, Aberdeen, UKAbstract: Ocular ultrasound is now in increasing demand in routine ophthalmic clinical practice not only because it is noninvasive but also because of ever-advancing technology providing higher resolution imaging. It is however a difficult branch of ophthalmic investigations to grasp, as it requires a high skill level to interface with the technology and provide accurate interpretation of images for ophthalmic diagnosis and management. It is even more labor intensive to teach ocular ultrasound to another fellow clinician. One of the fundamental skills that proved difficult to learn and teach is the need for the examiner to “mentally convert” 2-dimensional B-scan images into 3-dimensional (3D interpretations. An additional challenge is the requirement to carry out this task in real time. We have developed a novel approach to teach ocular ultrasound by using a novel 3D ocular model. A 3D virtual model is built using widely available, open source, software. The model is then used to generate movie clips simulating different movements and orientations of the scanner head. Using Blender, Quicktime motion clips are choreographed and collated into interactive quizzes and other pertinent pedagogical media. The process involves scripting motion vectors, rotation, and tracking of both the virtual stereo camera and the model. The resulting sequence is then rendered for twinned right- and left-eye views. Finally, the twinned views are synchronized and combined in a format compatible with the stereo projection apparatus. This new model will help the student with spatial awareness and allow for assimilation of this awareness into clinical practice. It will also help with grasping the nomenclature used in ocular ultrasound as well as helping with localization of

FLOWPLOT2, 2-D, 3-D Fluid Dynamic Plots

International Nuclear Information System (INIS)

Cobb, C.K.; Tunstall, J.N.

1989-01-01

1 - Description of program or function: FLOWPLOT2 is a plotting program used with numerical or analytical fluid dynamics codes to create velocity vector plots, contour plots of up to three fluid parameters (e.g. pressure, density, and temperature), two-dimensional profile plots, three-dimensional curve plots, and/or three-dimensional surface plots for either the u or v velocity components. If the fluid dynamics code computes a transient or simulated time related solution, FLOWPLOT2 can also be used to generate these plots for any specified time interval. Multiple cases generating different plots for different time intervals may be run in one execution of the program. In addition, plots can be created for selected two- dimensional planes of three-dimensional steady-state problems. The user has the option of producing plots on CalComp or Versatec plotters or microfiche and of creating a compressed dataset before plotting. 2 - Method of solution: FLOWPLOT2 reads a dataset written by the fluid dynamics code. This dataset must be written in a specified format and must contain parametric data at the nodal points of a uniform or non-uniform rectangular grid formed by the intersection of the grid lines of the model. 3 - Restrictions on the complexity of the problem - Maxima of: 2500 nodes, 40 y-values for 2-D profile plots and 3-D curve plots, 20 contour values, 3 fluid parameters

Two dimensional nanomaterials for flexible supercapacitors.

Science.gov (United States)

Peng, Xu; Peng, Lele; Wu, Changzheng; Xie, Yi

2014-05-21

Flexible supercapacitors, as one of most promising emerging energy storage devices, are of great interest owing to their high power density with great mechanical compliance, making them very suitable as power back-ups for future stretchable electronics. Two-dimensional (2D) nanomaterials, including the quasi-2D graphene and inorganic graphene-like materials (IGMs), have been greatly explored to providing huge potential for the development of flexible supercapacitors with higher electrochemical performance. This review article is devoted to recent progresses in engineering 2D nanomaterials for flexible supercapacitors, which survey the evolution of electrode materials, recent developments in 2D nanomaterials and their hybrid nanostructures with regulated electrical properties, and the new planar configurations of flexible supercapacitors. Furthermore, a brief discussion on future directions, challenges and opportunities in this fascinating area is also provided.

Mechanical stretching for tissue engineering: two-dimensional and three-dimensional constructs.

Science.gov (United States)

Riehl, Brandon D; Park, Jae-Hong; Kwon, Il Keun; Lim, Jung Yul

2012-08-01

Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.

Comparison of two-dimensional fast spin echo T2 weighted sequences and three-dimensional volume isotropic T2 weighted fast spin echo (VISTA) MRI in the evaluation of triangular fibrocartilage of the wrist.

Science.gov (United States)

Park, Hee Jin; Lee, So Yeon; Kang, Kyung A; Kim, Eun Young; Shin, Hun Kyu; Park, Se Jin; Park, Jai Hyung; Kim, Eugene

2018-04-01

To compare image quality of three-dimensional volume isotropic T 2 weighted fast spin echo (3D VISTA) and two-dimensional (2D) T 2 weighted images (T2WI) for evaluation of triangular fibrocartilage (TFC) and to investigate whether 3D VISTA can replace 2D T 2 WI in evaluating TFC injury. This retrospective study included 69 patients who received wrist MRIs using both 2D T 2 WI and 3D VISTA techniques for assessment of wrist pathology, including TFC injury. Two radiologists measured the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) of the two sequences. The anatomical identification score and diagnostic performance were independently assessed by two interpreters. The diagnostic abilities of 3D VISTA and 2D T 2 WI were analysed by sensitivity, specificity and accuracy for diagnosing TFC injury using surgically or clinically confirmed diagnostic reference standards. 17 cases (25%) were classified as having TFC injury. 2 cases (12%) were diagnosed surgically, and 15 cases (88%) were diagnosed by physical examination. 52 cases (75%) were diagnosed as having intact TFC. 8 of these cases (15%) were surgically confirmed, while the others were diagnosed by physical examination and clinical findings. The 3D VISTA images had significantly higher SNR and CNR values for the TFC than 2D T 2 WI images. The scores of 3D VISTA's total length, full width and sharpness were similar to those of 2D T 2 WI. We were unable to find a significant difference between 3D VISTA and 2D T 2 WI in the ability to diagnose TFC injury. 3D VISTA image quality is similar to that of 2D T 2 WI for TFC evaluation and is also excellent for tissue contrast. 3D VISTA can replace 2D images in TFC injury assessment. Advances in knowledge: 3D VISTA image quality is similar to that of 2D T 2 WI for TFC evaluation and is also excellent for tissue contrast. 3D VISTA can replace 2D images in TFC injury assessment.

Evaluating mental workload of two-dimensional and three-dimensional visualization for anatomical structure localization.

Science.gov (United States)

Foo, Jung-Leng; Martinez-Escobar, Marisol; Juhnke, Bethany; Cassidy, Keely; Hisley, Kenneth; Lobe, Thom; Winer, Eliot

2013-01-01

Visualization of medical data in three-dimensional (3D) or two-dimensional (2D) views is a complex area of research. In many fields 3D views are used to understand the shape of an object, and 2D views are used to understand spatial relationships. It is unclear how 2D/3D views play a role in the medical field. Using 3D views can potentially decrease the learning curve experienced with traditional 2D views by providing a whole representation of the patient's anatomy. However, there are challenges with 3D views compared with 2D. This current study expands on a previous study to evaluate the mental workload associated with both 2D and 3D views. Twenty-five first-year medical students were asked to localize three anatomical structures--gallbladder, celiac trunk, and superior mesenteric artery--in either 2D or 3D environments. Accuracy and time were taken as the objective measures for mental workload. The NASA Task Load Index (NASA-TLX) was used as a subjective measure for mental workload. Results showed that participants viewing in 3D had higher localization accuracy and a lower subjective measure of mental workload, specifically, the mental demand component of the NASA-TLX. Results from this study may prove useful for designing curricula in anatomy education and improving training procedures for surgeons.

Electronic Transport in Two-Dimensional Materials

Science.gov (United States)

Sangwan, Vinod K.; Hersam, Mark C.

2018-04-01

Two-dimensional (2D) materials have captured the attention of the scientific community due to the wide range of unique properties at nanometer-scale thicknesses. While significant exploratory research in 2D materials has been achieved, the understanding of 2D electronic transport and carrier dynamics remains in a nascent stage. Furthermore, because prior review articles have provided general overviews of 2D materials or specifically focused on charge transport in graphene, here we instead highlight charge transport mechanisms in post-graphene 2D materials, with particular emphasis on transition metal dichalcogenides and black phosphorus. For these systems, we delineate the intricacies of electronic transport, including band structure control with thickness and external fields, valley polarization, scattering mechanisms, electrical contacts, and doping. In addition, electronic interactions between 2D materials are considered in the form of van der Waals heterojunctions and composite films. This review concludes with a perspective on the most promising future directions in this fast-evolving field.

Two-dimensional heterostructures for energy storage

Energy Technology Data Exchange (ETDEWEB)

Gogotsi, Yury G. [Drexel Univ., Philadelphia, PA (United States); Pomerantseva, Ekaterina [Drexel Univ., Philadelphia, PA (United States)

2017-06-12

Two-dimensional (2D) materials provide slit-shaped ion diffusion channels that enable fast movement of lithium and other ions. However, electronic conductivity, the number of intercalation sites, and stability during extended cycling are also crucial for building high-performance energy storage devices. While individual 2D materials, such as graphene, show some of the required properties, none of them can offer all properties needed to maximize energy density, power density, and cycle life. Here we argue that stacking different 2D materials into heterostructured architectures opens an opportunity to construct electrodes that would combine the advantages of the individual building blocks while eliminating the associated shortcomings. We discuss characteristics of common 2D materials and provide examples of 2D heterostructured electrodes that showed new phenomena leading to superior electrochemical performance. As a result, we also consider electrode fabrication approaches and finally outline future steps to create 2D heterostructured electrodes that could greatly expand current energy storage technologies.

Reliability of pelvic floor measurements on three- and four-dimensional ultrasound during and after first pregnancy: implications for training.

Science.gov (United States)

van Veelen, G A; Schweitzer, K J; van der Vaart, C H

2013-11-01

To evaluate the reliability of measurements of the levator hiatus and levator-urethra gap (LUG) using three/four-dimensional (3D/4D) transperineal ultrasound in women during their first pregnancy and 6 months postpartum, and to assess the learning process for these measurements. An inexperienced observer was taught to perform measurements of the levator hiatus and LUG by an experienced observer. After training, 3D/4D ultrasound volume datasets of 40 women in the first trimester were analyzed by these two observers. Another training session then took place and both observers repeated the analyses of the same volume datasets. Finally, analyses of 40 volume datasets of the women 6 months postpartum were performed by both observers. Intra- and interobserver reliability were determined by intraclass correlation coefficients (ICC) with 95% CIs. For levator hiatal measurements, in the women during their first pregnancy the interobserver reliability was substantial to almost perfect after both the first and second training session (ICC, 0.62-0.83 and 0.71-0.89, respectively, for anteroposterior diameter, transverse diameter and area at rest, on contraction and on Valsalva) and the intraobserver reliability was substantial to almost perfect for both observers. For these measurements performed once the women had delivered, interobserver reliability was moderate to almost perfect. For LUG measurements performed during pregnancy, interobserver reliability was slight to moderate after the first training session (ICC, 0.14-0.54), but improved after the second training session (ICC, 0.38-0.71), and intraobserver reliability was moderate to substantial for the experienced observer and slight to moderate for the inexperienced observer. For these measurements performed when the women had delivered, interobserver reliability was fair to moderate. The levator hiatus and LUG can be measured reliably using 3D/4D ultrasound in primigravid and primiparous women. The technique to measure

User's manual for DYNA2D: an explicit two-dimensional hydrodynamic finite-element code with interactive rezoning

Energy Technology Data Exchange (ETDEWEB)

Hallquist, J.O.

1982-02-01

This revised report provides an updated user's manual for DYNA2D, an explicit two-dimensional axisymmetric and plane strain finite element code for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. A contact-impact algorithm permits gaps and sliding along material interfaces. By a specialization of this algorithm, such interfaces can be rigidly tied to admit variable zoning without the need of transition regions. Spatial discretization is achieved by the use of 4-node solid elements, and the equations-of motion are integrated by the central difference method. An interactive rezoner eliminates the need to terminate the calculation when the mesh becomes too distorted. Rather, the mesh can be rezoned and the calculation continued. The command structure for the rezoner is described and illustrated by an example.

Two-dimensional N = 2 Super-Yang-Mills Theory

Science.gov (United States)

August, Daniel; Wellegehausen, Björn; Wipf, Andreas

2018-03-01

Supersymmetry is one of the possible scenarios for physics beyond the standard model. The building blocks of this scenario are supersymmetric gauge theories. In our work we study the N = 1 Super-Yang-Mills (SYM) theory with gauge group SU(2) dimensionally reduced to two-dimensional N = 2 SYM theory. In our lattice formulation we break supersymmetry and chiral symmetry explicitly while preserving R symmetry. By fine tuning the bar-mass of the fermions in the Lagrangian we construct a supersymmetric continuum theory. To this aim we carefully investigate mass spectra and Ward identities, which both show a clear signal of supersymmetry restoration in the continuum limit.

Standardization of the first-trimester fetal cardiac examination using spatiotemporal image correlation with tomographic ultrasound and color Doppler imaging.

Science.gov (United States)

Turan, S; Turan, O M; Ty-Torredes, K; Harman, C R; Baschat, A A

2009-06-01

The challenges of the first-trimester examination of the fetal heart may in part be overcome by technical advances in three-dimensional (3D) ultrasound techniques. Our aim was to standardize the first-trimester 3D imaging approach to the cardiac examination to provide the most consistent and accurate display of anatomy. Low-risk women with normal findings on first-trimester screening at 11 to 13 + 6 weeks had cardiac ultrasound using the following sequence: (1) identification of the four-chamber view; (2) four-dimensional (4D) volume acquisition with spatiotemporal image correlation (STIC) and color Doppler imaging (angle = 20 degrees, sweep 10 s); (3) offline, tomographic ultrasound imaging (TUI) analysis with standardized starting plane (four-chamber view), slice number and thickness; (4) assessment of fetal cardiac anatomy (four-chamber view, cardiac axis, size and symmetry, atrioventricular valves, great arteries and descending aorta) with and without color Doppler. 107 consecutive women (age, 16-42 years, body mass index 17.2-50.2 kg/m(2)) were studied. A minimum of three 3D volumes were obtained for each patient, transabdominally in 91.6%. Fetal motion artifact required acquisition of more than three volumes in 20%. The median time for TUI offline analysis was 100 (range, 60-240) s. Individual anatomic landmarks were identified in 89.7-99.1%. Visualization of all structures in one panel was observed in 91 patients (85%). Starting from a simple two-dimensional cardiac landmark-the four-chamber view-the standardized STIC-TUI technique enables detailed segmental cardiac evaluation of the normal fetal heart in the first trimester. (c) 2009 ISUOG.

Solution-Based Processing and Applications of Two-Dimensional Heterostructures

Science.gov (United States)

Hersam, Mark

Two-dimensional materials have emerged as promising candidates for next-generation electronics and optoelectronics, but advances in scalable nanomanufacturing are required to exploit this potential in real-world technology. This talk will explore methods for improving the uniformity of solution-processed two-dimensional materials with an eye toward realizing dispersions and inks that can be deposited into large-area thin-films. In particular, density gradient ultracentrifugation allows the solution-based isolation of graphene, boron nitride, montmorillonite, and transition metal dichalcogenides (e.g., MoS2, WS2, ReS2, MoSe2, WSe2) with homogeneous thickness down to the atomically thin limit. Similarly, two-dimensional black phosphorus is isolated in organic solvents or deoxygenated aqueous surfactant solutions with the resulting phosphorene nanosheets showing field-effect transistor mobilities and on/off ratios that are comparable to micromechanically exfoliated flakes. By adding cellulosic polymer stabilizers to these dispersions, the rheological properties can be tuned by orders of magnitude, thereby enabling two-dimensional material inks that are compatible with a range of additive manufacturing methods including inkjet, gravure, screen, and 3D printing. The resulting solution-processed two-dimensional heterostructures show promise in several device applications including photodiodes, anti-ambipolar transistors, gate-tunable memristors, and heterojunction photovoltaics.

Nonlinear dynamic characterization of two-dimensional materials

NARCIS (Netherlands)

Davidovikj, D.; Alijani, F.; Cartamil Bueno, S.J.; van der Zant, H.S.J.; Amabili, M.; Steeneken, P.G.

2017-01-01

Owing to their atomic-scale thickness, the resonances of two-dimensional (2D) material membranes show signatures of nonlinearities at forces of only a few picoNewtons. Although the linear dynamics of membranes is well understood, the exact relation between the nonlinear response and the resonator's

Band Alignment Determination of Two-Dimensional Heterojunctions and Their Electronic Applications

KAUST Repository

Chiu, Ming-Hui

2018-01-01

Two-dimensional (2D) layered materials such as MoS2 have been recognized as high on-off ratio semiconductors which are promising candidates for electronic and optoelectronic devices. In addition to the use of individual 2D materials, the accelerated

A new method for information retrieval in two-dimensional grating-based X-ray phase contrast imaging

International Nuclear Information System (INIS)

Wang Zhi-Li; Gao Kun; Chen Jian; Ge Xin; Tian Yang-Chao; Wu Zi-Yu; Zhu Pei-Ping

2012-01-01

Grating-based X-ray phase contrast imaging has been demonstrated to be an extremely powerful phase-sensitive imaging technique. By using two-dimensional (2D) gratings, the observable contrast is extended to two refraction directions. Recently, we have developed a novel reverse-projection (RP) method, which is capable of retrieving the object information efficiently with one-dimensional (1D) grating-based phase contrast imaging. In this contribution, we present its extension to the 2D grating-based X-ray phase contrast imaging, named the two-dimensional reverse-projection (2D-RP) method, for information retrieval. The method takes into account the nonlinear contributions of two refraction directions and allows the retrieval of the absorption, the horizontal and the vertical refraction images. The obtained information can be used for the reconstruction of the three-dimensional phase gradient field, and for an improved phase map retrieval and reconstruction. Numerical experiments are carried out, and the results confirm the validity of the 2D-RP method

Therapeutic response assessment using 3D ultrasound for hepatic metastasis from colorectal cancer: Application of a personalized, 3D-printed tumor model using CT images.

Directory of Open Access Journals (Sweden)

Ye Ra Choi

Full Text Available To evaluate accuracy and reliability of three-dimensional ultrasound (3D US for response evaluation of hepatic metastasis from colorectal cancer (CRC using a personalized 3D-printed tumor model.Twenty patients with liver metastasis from CRC who underwent baseline and after chemotherapy CT, were retrospectively included. Personalized 3D-printed tumor models using CT were fabricated. Two radiologists measured volume of each 3D printing model using 3D US. With CT as a reference, we compared difference between CT and US tumor volume. The response evaluation was based on Response Evaluation Criteria in Solid Tumors (RECIST criteria.3D US tumor volume showed no significant difference from CT volume (7.18 ± 5.44 mL, 8.31 ± 6.32 mL vs 7.42 ± 5.76 mL in CT, p>0.05. 3D US provided a high correlation coefficient with CT (r = 0.953, r = 0.97 as well as a high inter-observer intraclass correlation (0.978; 0.958-0.988. Regarding response, 3D US was in agreement with CT in 17 and 18 out of 20 patients for observer 1 and 2 with excellent agreement (κ = 0.961.3D US tumor volume using a personalized 3D-printed model is an accurate and reliable method for the response evaluation in comparison with CT tumor volume.

Two-dimensional fourier transform spectrometer

Science.gov (United States)

DeFlores, Lauren; Tokmakoff, Andrei

2013-09-03

The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

Dynamical observations on the crack tip zone and stress corrosion of two-dimensional MoS2

KAUST Repository

Ly, Thuc Hue

2017-01-18

Whether and how fracture mechanics needs to be modified for small length scales and in systems of reduced dimensionality remains an open debate. Here, employing in situ transmission electron microscopy, atomic structures and dislocation dynamics in the crack tip zone of a propagating crack in two-dimensional (2D) monolayer MoS2 membrane are observed, and atom-to-atom displacement mapping is obtained. The electron beam is used to initiate the crack; during in situ observation of crack propagation the electron beam effect is minimized. The observed high-frequency emission of dislocations is beyond previous understanding of the fracture of brittle MoS2. Strain analysis reveals dislocation emission to be closely associated with the crack propagation path in nanoscale. The critical crack tip plastic zone size of nearly perfect 2D MoS2 is between 2 and 5 nm, although it can grow to 10 nm under corrosive conditions such as ultraviolet light exposure, showing enhanced dislocation activity via defect generation.

Ultrasound-assisted lipase-catalyzed synthesis of D-isoascorbyl palmitate: process optimization and Kinetic evaluation.

Science.gov (United States)

Cui, Feng-Jie; Zhao, Hong-Xia; Sun, Wen-Jing; Wei, Zhuan; Yu, Si-Lian; Zhou, Qiang; Dong, Ying

2013-12-09

D-isoascorbic acid is a food antioxidant additive and used in accordance with Good Manufacturing Practice (GMP). High solubility in water (about 150 g/L at 25°C) reduces its effectiveness in stabilizing fats and oils. Our research group had successfully synthesized D-isoascorbyl palmitate using immobilized lipase Novozym 435 as a biocatalyst. Low production efficiency of D-isoascorbyl palmitate is still a problem for industrial production due to the long reaction time of over 24 h. In the present work, ultrasonic treatment was applied for accelerating the reaction process. The operation parameters were optimized to obtain the maximum D-isoascorbyl palmitate conversion rate by using a 5-level-4-factor Central Composite Design (CCD) and Response Surface Methdology (RSM). The reaction apparent kinetic parameters under the ultrasound treatment and mechanical shaking conditions were also determined and compared. Results showed that ultrasound treatment decreased the reaction time by over 50%. D-isoascorbyl palmitate yielded to 94.32 ± 0.17% and the productivity reached to 8.67 g L-1 h-1 under the optimized conditions as: 9% of enzyme load (w/w), 61°C of reaction temperature, 1:5 of D- isoascorbic-to-palmitic acid molar ratio, and 137 W of the ultrasound power. The immobilized lipase Novozym 435 could be reused for 7 times with 65% of the remained D-isoascorbyl palmitate conversion rate. The reaction kinetics showed that the maximum apparent reaction rate (vmax) of the ultrasound-assisted reaction was 2.85 times higher than that of the mechanical shaking, which proved that ultrasound treatment significantly enhanced the reaction efficiency. A systematic study on ultrasound-assisted enzymatic esterification for D-isoascorbyl palmitate production is reported. The results show a promising perspective of the ultrasound technique to reduce the reaction time and improve the production efficiency. The commercial D-isoascorbyl palmitate synthesis will be potentially

Tunneling between parallel two-dimensional electron liquids

Czech Academy of Sciences Publication Activity Database

Jungwirth, Tomáš; MacDonald, A. H.

361/362, - (1996), s. 167-170 ISSN 0039-6028. [International Conference on the Electronic Properties of Two Dimensional Systems /11./. Nottingham, 07.08.1995-11.08.1995] R&D Projects: GA ČR GA202/94/1278 Grant - others:INT(XX) 9106888 Impact factor: 2.783, year: 1996

Sonocubic fine: new three-dimensional ultrasound software to the screening of congenital heart diseases

Directory of Open Access Journals (Sweden)

Edward Araujo Júnior

2014-09-01

Full Text Available Congenital heart disease is the most common fetal congenital malformations; however, the prenatal rate detection still is low. The two-dimensional echocardiography is the "gold standard" exam to screening and diagnosis of congenital heart disease during the prenatal; however, this exam is operator-depending and it is realized only in high risk pregnancies. Spatio-temporal image correlation is a three-dimensional ultrasound software that analyses the fetal heart and your connections in the multiplanar and rendering modes; however, spatio-temporal image correlation too is operator-depending and time-consuming. We presenting a new three-dimensional software named Sonocubic fine to the screening of congenital heart disease. This software applies intelligent navigation technology to spatio-temporal image correlation volume datasets to automatically generate nine fetal echocardiography standard views. Thus, this new software tends to be less operator-depending and time-consuming.

Two-dimensional inverse opal hydrogel for pH sensing.

Science.gov (United States)

Xue, Fei; Meng, Zihui; Qi, Fenglian; Xue, Min; Wang, Fengyan; Chen, Wei; Yan, Zequn

2014-12-07

A novel hydrogel film with a highly ordered macropore monolayer on its surface was prepared by templated photo-polymerization of hydrogel monomers on a two-dimensional (2D) polystyrene colloidal array. The 2D inverse opal hydrogel has prominent advantages over traditional three-dimensional (3D) inverse opal hydrogels. First, the formation of the 2D array template through a self-assembly method is considerably faster and simpler. Second, the stable ordering structure of the 2D array template makes it easier to introduce the polymerization solution into the template. Third, a simple measurement, a Debye diffraction ring, is utilized to characterize the neighboring pore spacing of the 2D inverse opal hydrogel. Acrylic acid was copolymerized into the hydrogel; thus, the hydrogel responded to pH through volume change, which resulted from the formation of the Donnan potential. The 2D inverse opal hydrogel showed that the neighboring pore spacing increased by about 150 nm and diffracted color red-shifted from blue to red as the pH increased from pH 2 to 7. In addition, the pH response kinetics and ionic strength effect of this 2D mesoporous polymer film were also investigated.

Use of translabial three-dimensional power Doppler ultrasound for cervical assessment before labor induction.

Science.gov (United States)

Esin, Sertac; Yirci, Bulent; Yalvac, Serdar; Kandemir, Omer

2017-07-26

To compare translabial three-dimensional (3D) power Doppler ultrasound with Bishop score and transvaginal ultrasound measurements for cervical assessment before induction of labor with dinoprostone or cervical ripening balloon. Translabial cervical volume and length, vascularization indices and transvaginal cervical length were measured. Results were compared among women who had vaginal delivery at 24 h or less and more than 24 h after the insertion of the dinoprostone vaginal insert or cervical ripening balloon and among women who had vaginal delivery and cesarean delivery for failure to go into labor or failure to progress. There was no correlation between the time to delivery after a ripening agent was applied and translabial cervical volume, translabial cervical length, vascularization index (VI), flow index (FI), vascularization flow index (VFI), transvaginal cervical length and Bishop scores. The ultrasonographic measurements were no different among women who had vaginal delivery at 24 h or less and more than 24 h and among women who had vaginal delivery and cesarean delivery for failure to go into labor or failure to progress. In this study, we failed to demonstrate the superiority of translabial 3D ultrasonography over Bishop score and transvaginal ultrasonography for predicting the success of induction of labor.

TWO-DIMENSIONAL CORE-COLLAPSE SUPERNOVA MODELS WITH MULTI-DIMENSIONAL TRANSPORT

International Nuclear Information System (INIS)

Dolence, Joshua C.; Burrows, Adam; Zhang, Weiqun

2015-01-01

We present new two-dimensional (2D) axisymmetric neutrino radiation/hydrodynamic models of core-collapse supernova (CCSN) cores. We use the CASTRO code, which incorporates truly multi-dimensional, multi-group, flux-limited diffusion (MGFLD) neutrino transport, including all relevant O(v/c) terms. Our main motivation for carrying out this study is to compare with recent 2D models produced by other groups who have obtained explosions for some progenitor stars and with recent 2D VULCAN results that did not incorporate O(v/c) terms. We follow the evolution of 12, 15, 20, and 25 solar-mass progenitors to approximately 600 ms after bounce and do not obtain an explosion in any of these models. Though the reason for the qualitative disagreement among the groups engaged in CCSN modeling remains unclear, we speculate that the simplifying ''ray-by-ray'' approach employed by all other groups may be compromising their results. We show that ''ray-by-ray'' calculations greatly exaggerate the angular and temporal variations of the neutrino fluxes, which we argue are better captured by our multi-dimensional MGFLD approach. On the other hand, our 2D models also make approximations, making it difficult to draw definitive conclusions concerning the root of the differences between groups. We discuss some of the diagnostics often employed in the analyses of CCSN simulations and highlight the intimate relationship between the various explosion conditions that have been proposed. Finally, we explore the ingredients that may be missing in current calculations that may be important in reproducing the properties of the average CCSNe, should the delayed neutrino-heating mechanism be the correct mechanism of explosion

3D ultrasound imaging for prosthesis fabrication and diagnostic imaging

Energy Technology Data Exchange (ETDEWEB)

Morimoto, A.K.; Bow, W.J.; Strong, D.S. [and others

1995-06-01

The fabrication of a prosthetic socket for a below-the-knee amputee requires knowledge of the underlying bone structure in order to provide pressure relief for sensitive areas and support for load bearing areas. The goal is to enable the residual limb to bear pressure with greater ease and utility. Conventional methods of prosthesis fabrication are based on limited knowledge about the patient`s underlying bone structure. A 3D ultrasound imaging system was developed at Sandia National Laboratories. The imaging system provides information about the location of the bones in the residual limb along with the shape of the skin surface. Computer assisted design (CAD) software can use this data to design prosthetic sockets for amputees. Ultrasound was selected as the imaging modality. A computer model was developed to analyze the effect of the various scanning parameters and to assist in the design of the overall system. The 3D ultrasound imaging system combines off-the-shelf technology for image capturing, custom hardware, and control and image processing software to generate two types of image data -- volumetric and planar. Both volumetric and planar images reveal definition of skin and bone geometry with planar images providing details on muscle fascial planes, muscle/fat interfaces, and blood vessel definition. The 3D ultrasound imaging system was tested on 9 unilateral below-the- knee amputees. Image data was acquired from both the sound limb and the residual limb. The imaging system was operated in both volumetric and planar formats. An x-ray CT (Computed Tomography) scan was performed on each amputee for comparison. Results of the test indicate beneficial use of ultrasound to generate databases for fabrication of prostheses at a lower cost and with better initial fit as compared to manually fabricated prostheses.

Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

International Nuclear Information System (INIS)

Meckel, Stephan; Leitner, Lorenz; Schubert, Tilman; Bonati, Leo H.; Lyrer, Philippe; Santini, Francesco; Stalder, Aurelien F.; Markl, Michael; Wetzel, Stephan G.

2013-01-01

4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

Airy beams on two dimensional materials

Science.gov (United States)

Imran, Muhammad; Li, Rujiang; Jiang, Yuyu; Lin, Xiao; Zheng, Bin; Dehdashti, Shahram; Xu, Zhiwei; Wang, Huaping

2018-05-01

We propose that quasi-transverse-magnetic (quasi-TM) Airy beams can be supported on two dimensional (2D) materials. By taking graphene as a typical example, the solution of quasi-TM Airy beams is studied under the paraxial approximation. The analytical field intensity in a bilayer graphene-based planar plasmonic waveguide is confirmed by the simulation results. Due to the tunability of the chemical potential of graphene, the self-accelerating behavior of the quasi-TM Airy beam can be steered effectively. 2D materials thus provide a good platform to investigate the propagation of Airy beams.

Two-dimensional materials for ultrafast lasers

International Nuclear Information System (INIS)

Wang Fengqiu

2017-01-01

As the fundamental optical properties and novel photophysics of graphene and related two-dimensional (2D) crystals are being extensively investigated and revealed, a range of potential applications in optical and optoelectronic devices have been proposed and demonstrated. Of the many possibilities, the use of 2D materials as broadband, cost-effective and versatile ultrafast optical switches (or saturable absorbers) for short-pulsed lasers constitutes a rapidly developing field with not only a good number of publications, but also a promising prospect for commercial exploitation. This review primarily focuses on the recent development of pulsed lasers based on several representative 2D materials. The comparative advantages of these materials are discussed, and challenges to practical exploitation, which represent good future directions of research, are laid out. (paper)

Two-dimensional NMR spectrometry

International Nuclear Information System (INIS)

Farrar, T.C.

1987-01-01

This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t 0 ; an evolution period, t 1 ; and a detection period, t 2

Insight into Resolution Enhancement in Generalized Two-Dimensional Correlation Spectroscopy

OpenAIRE

Ma, Lu; Sikirzhytski, Vitali; Hong, Zhenmin; Lednev, Igor K.; Asher, Sanford A.

2013-01-01

Generalized two-dimensional correlation spectroscopy (2D COS) can be used to enhance spectral resolution in order to help differentiate highly overlapped spectral bands. Despite the numerous extensive 2D COS investigations, the origin of the 2D spectral resolution enhancement mechanism(s) are not completely understood. In the work here we studied the 2D COS of simulated spectra in order to develop new insights into the dependence of the 2D COS spectral features on the overlapping band separat...

Three-dimensional liver motion tracking using real-time two-dimensional MRI.

Science.gov (United States)

Brix, Lau; Ringgaard, Steffen; Sørensen, Thomas Sangild; Poulsen, Per Rugaard

2014-04-01

Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Axial, sagittal, and coronal 2D MRI series

Three-dimensional liver motion tracking using real-time two-dimensional MRI

Energy Technology Data Exchange (ETDEWEB)

Brix, Lau, E-mail: lau.brix@stab.rm.dk [Department of Procurement and Clinical Engineering, Region Midt, Olof Palmes Allé 15, 8200 Aarhus N, Denmark and MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Ringgaard, Steffen [MR Research Centre, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Sørensen, Thomas Sangild [Department of Computer Science, Aarhus University, Aabogade 34, 8200 Aarhus N, Denmark and Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Poulsen, Per Rugaard [Department of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N, Denmark and Department of Oncology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C (Denmark)

2014-04-15

Purpose: Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. Methods: The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Results: Axial, sagittal

Three-dimensional liver motion tracking using real-time two-dimensional MRI

International Nuclear Information System (INIS)

Brix, Lau; Ringgaard, Steffen; Sørensen, Thomas Sangild; Poulsen, Per Rugaard

2014-01-01

Purpose: Combined magnetic resonance imaging (MRI) systems and linear accelerators for radiotherapy (MR-Linacs) are currently under development. MRI is noninvasive and nonionizing and can produce images with high soft tissue contrast. However, new tracking methods are required to obtain fast real-time spatial target localization. This study develops and evaluates a method for tracking three-dimensional (3D) respiratory liver motion in two-dimensional (2D) real-time MRI image series with high temporal and spatial resolution. Methods: The proposed method for 3D tracking in 2D real-time MRI series has three steps: (1) Recording of a 3D MRI scan and selection of a blood vessel (or tumor) structure to be tracked in subsequent 2D MRI series. (2) Generation of a library of 2D image templates oriented parallel to the 2D MRI image series by reslicing and resampling the 3D MRI scan. (3) 3D tracking of the selected structure in each real-time 2D image by finding the template and template position that yield the highest normalized cross correlation coefficient with the image. Since the tracked structure has a known 3D position relative to each template, the selection and 2D localization of a specific template translates into quantification of both the through-plane and in-plane position of the structure. As a proof of principle, 3D tracking of liver blood vessel structures was performed in five healthy volunteers in two 5.4 Hz axial, sagittal, and coronal real-time 2D MRI series of 30 s duration. In each 2D MRI series, the 3D localization was carried out twice, using nonoverlapping template libraries, which resulted in a total of 12 estimated 3D trajectories per volunteer. Validation tests carried out to support the tracking algorithm included quantification of the breathing induced 3D liver motion and liver motion directionality for the volunteers, and comparison of 2D MRI estimated positions of a structure in a watermelon with the actual positions. Results: Axial, sagittal

A new two dimensional spectral/spatial multi-diagonal code for noncoherent optical code division multiple access (OCDMA) systems

Science.gov (United States)

Kadhim, Rasim Azeez; Fadhil, Hilal Adnan; Aljunid, S. A.; Razalli, Mohamad Shahrazel

2014-10-01

A new two dimensional codes family, namely two dimensional multi-diagonal (2D-MD) codes, is proposed for spectral/spatial non-coherent OCDMA systems based on the one dimensional MD code. Since the MD code has the property of zero cross correlation, the proposed 2D-MD code also has this property. So that, the multi-access interference (MAI) is fully eliminated and the phase induced intensity noise (PIIN) is suppressed with the proposed code. Code performance is analyzed in terms of bit error rate (BER) while considering the effect of shot noise, PIIN, and thermal noise. The performance of the proposed code is compared with the related MD, modified quadratic congruence (MQC), two dimensional perfect difference (2D-PD) and two dimensional diluted perfect difference (2D-DPD) codes. The analytical and the simulation results reveal that the proposed 2D-MD code outperforms the other codes. Moreover, a large number of simultaneous users can be accommodated at low BER and high data rate.

Two dimensional topological insulator in quantizing magnetic fields

Science.gov (United States)

Olshanetsky, E. B.; Kvon, Z. D.; Gusev, G. M.; Mikhailov, N. N.; Dvoretsky, S. A.

2018-05-01

The effect of quantizing magnetic field on the electron transport is investigated in a two dimensional topological insulator (2D TI) based on a 8 nm (013) HgTe quantum well (QW). The local resistance behavior is indicative of a metal-insulator transition at B ≈ 6 T. On the whole the experimental data agrees with the theory according to which the helical edge states transport in a 2D TI persists from zero up to a critical magnetic field Bc after which a gap opens up in the 2D TI spectrum.

Development of new two-dimensional spectral/spatial code based on dynamic cyclic shift code for OCDMA system

Science.gov (United States)

Jellali, Nabiha; Najjar, Monia; Ferchichi, Moez; Rezig, Houria

2017-07-01

In this paper, a new two-dimensional spectral/spatial codes family, named two dimensional dynamic cyclic shift codes (2D-DCS) is introduced. The 2D-DCS codes are derived from the dynamic cyclic shift code for the spectral and spatial coding. The proposed system can fully eliminate the multiple access interference (MAI) by using the MAI cancellation property. The effect of shot noise, phase-induced intensity noise and thermal noise are used to analyze the code performance. In comparison with existing two dimensional (2D) codes, such as 2D perfect difference (2D-PD), 2D Extended Enhanced Double Weight (2D-Extended-EDW) and 2D hybrid (2D-FCC/MDW) codes, the numerical results show that our proposed codes have the best performance. By keeping the same code length and increasing the spatial code, the performance of our 2D-DCS system is enhanced: it provides higher data rates while using lower transmitted power and a smaller spectral width.

Orbital order and effective mass enhancement in t2 g two-dimensional electron gases