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Sample records for palate helical ct

  1. Helical CT of abdominal trauma.

    PubMed

    Novelline, R A; Rhea, J T; Bell, T

    1999-05-01

    CT has revolutionized the diagnostic work-up of trauma patients with suspected abdominal injuries. A wide range of intraperitoneal and retroperitoneal organ injuries can be quickly and accurately diagnosed with CT. Today, helical CT technology permits even faster examinations, with improved intravenous contrast opacification of parenchymal organs and vascular structures and reduced CT artifacts caused by patient motion, respiration, and arterial pulsation. Severely injured and potentially unstable patients, who might not have been able to tolerate the long CT examinations of the past, may be quickly evaluated today with helical CT. Accurate diagnosis requires high quality CT examinations that are performed with optimum CT protocols. This article reviews the currently recommended helical CT protocols for evaluating patients with suspected abdominal injuries, and the CT findings when injuries are present.

  2. Helical CT in emergency radiology.

    PubMed

    Novelline, R A; Rhea, J T; Rao, P M; Stuk, J L

    1999-11-01

    Today, a wide range of traumatic and nontraumatic emergency conditions are quickly and accurately diagnosed with helical computed tomography (CT). Many traditional emergency imaging procedures have been replaced with newer helical CT techniques that can be performed in less time and with greater accuracy, less patient discomfort, and decreased cost. The speed of helical technology permits CT examination of seriously ill patients in the emergency department, as well as patients who might not have been taken to CT previously because of the length of the examinations of the past. Also, helical technology permits multiple, sequential CT scans to be quickly obtained in the same patient, a great advance for the multiple-trauma patient. Higher quality CT examinations result from decreased respiratory misregistration, enhanced intravenous contrast material opacification of vascular structures and parenchymal organs, greater flexibility in image reconstruction, and improved multiplanar and three-dimensional reformations. This report summarizes the role and recommended protocols for the helical CT diagnosis of thoracic aortic trauma; aortic dissection; pulmonary embolism; acute conditions of the neck soft tissues; abdominal trauma; urinary tract stones; appendicitis; diverticulitis; abdominal aortic aneurysm; fractures of the face, spine, and extremities; and acute stroke.

  3. Helical CT of appendicitis and diverticulitis.

    PubMed

    Rao, P M; Rhea, J T; Novelline, R A

    1999-09-01

    The clinical diagnosis of appendicitis and diverticulitis remains challenging. Clinical diagnosis alone can lead to unnecessary hospitalizations and surgeries, prolonged periods of hospital observation, and delays prior to necessary medical or surgical treatment. Helical CT combined with recently reported techniques for imaging appendicitis and diverticulitis offers rapid and accurate confirmation or exclusion of these entities as well as identification of alternative conditions that can clinically mimic them. More routine use of helical CT holds great promise for improving patient care and lowering hospital resource use in patients with clinically suspected appendicitis and diverticulitis.

  4. Penetrating neck injuries: helical CT angiography for initial evaluation.

    PubMed

    Múnera, Felipe; Soto, Jorge A; Palacio, Diana M; Castañeda, Jorge; Morales, Carlos; Sanabria, Alvaro; Gutiérrez, Juan E; García, Giovanni

    2002-08-01

    To report an experience with helical computed tomographic (CT) angiography as the initial procedure to rule out arterial lesions caused by penetrating neck injuries. During 27 months, 175 patients were referred for helical CT angiography of the neck because of clinical suspicion of arterial injuries. The protocol included a 100-mL bolus of nonionic contrast material injected at 4.5 mL/sec, with 11-second scanning delay, 3-mm collimation, and pitch of 1.3-2.0. CT images were interpreted prospectively by the emergency radiologist, and two radiologists retrospectively interpreted studies with consensus. Outcome was determined with examination of patients and their charts. The sensitivity, specificity, and positive and negative predictive values were calculated. Studies in two patients were considered inadequate for diagnosis; these patients were referred for conventional arteriography and had normal findings. In 27 patients (15.6%), arterial lesions were detected. One patient had two arterial injuries. Lesions demonstrated with helical CT angiography were arterial occlusion (n = 14), pseudoaneurysm (n = 8), pseudoaneurysm and arteriovenous fistulae (n = 4), and partial thrombosis (n = 2). The remaining 146 patients had normal arteries. On the basis of these findings, patients were treated with surgery (n = 21), endovascular intervention (n = 7), and observation alone (n = 146). Results indicate that helical CT angiography can be used as the initial method for evaluation in patients with possible arterial injuries of the neck. Copyright RSNA, 2002

  5. Primary Cardiac Lymphoma: Helical CT Findings and Radiopathologic Correlation

    SciTech Connect

    Marco de Lucas, Enrique Pagola, Miguel Angel; Fernandez, Fidel; Lastra, Pedro; Delgado, M. Luisa Ruiz; Sadaba, Pablo; Pinto, Jesus; Ballesteros, Ma Angeles; Ortiz, Antonio

    2004-03-15

    Primary tumors of the heart are extremely rare.Clinical manifestations are nondiagnostic and the patients are often misdiagnosed. Magnetic resonance imaging and echocardiography are standard in this diagnostic workup. We report a case of a man with acromegaly, dysphagia, chest pain and weight loss. An invasive cardiac mass was diagnosed by helical-CT. Autopsy demonstrated a B-cell aggressive lymphoma.

  6. A rigid motion correction method for helical computed tomography (CT)

    NASA Astrophysics Data System (ADS)

    Kim, J.-H.; Nuyts, J.; Kyme, A.; Kuncic, Z.; Fulton, R.

    2015-03-01

    We propose a method to compensate for six degree-of-freedom rigid motion in helical CT of the head. The method is demonstrated in simulations and in helical scans performed on a 16-slice CT scanner. Scans of a Hoffman brain phantom were acquired while an optical motion tracking system recorded the motion of the bed and the phantom. Motion correction was performed by restoring projection consistency using data from the motion tracking system, and reconstructing with an iterative fully 3D algorithm. Motion correction accuracy was evaluated by comparing reconstructed images with a stationary reference scan. We also investigated the effects on accuracy of tracker sampling rate, measurement jitter, interpolation of tracker measurements, and the synchronization of motion data and CT projections. After optimization of these aspects, motion corrected images corresponded remarkably closely to images of the stationary phantom with correlation and similarity coefficients both above 0.9. We performed a simulation study using volunteer head motion and found similarly that our method is capable of compensating effectively for realistic human head movements. To the best of our knowledge, this is the first practical demonstration of generalized rigid motion correction in helical CT. Its clinical value, which we have yet to explore, may be significant. For example it could reduce the necessity for repeat scans and resource-intensive anesthetic and sedation procedures in patient groups prone to motion, such as young children. It is not only applicable to dedicated CT imaging, but also to hybrid PET/CT and SPECT/CT, where it could also ensure an accurate CT image for lesion localization and attenuation correction of the functional image data.

  7. Videotaped helical CT images for lung cancer screening.

    PubMed

    Iwano, S; Makino, N; Ikeda, M; Itoh, S; Ishihara, S; Tadokoro, M; Ishigaki, T

    2000-01-01

    The goal of this work was to determine a radiologist's ability to detect solitary pulmonary nodules on helical CT using both video (cine) viewing and film-based viewing. Sixty-five chest helical CT studies were reviewed. Six radiologists searched for 40 lung nodules on CT images presented in three formats. Film-based viewing of images at 10 and 5 mm increments was performed with a light box. Video viewing of the same examinations was performed in 5 mm increments at 2 frames/s. The area under the receiver operating characteristic curve (Az) measured the observer's ability to detect nodules. The Az was 0.948 for the video viewing, 0.844 for 5 mm increment film-based viewing, and 0.879 for 10 mm increment film-based viewing. There were no statistically significant differences. Lung nodules can be detected with similar detection rates when viewing conventional film or videotaped helical CT images. Videotaped images incur a lower cost, an important consideration in mass screening for lung cancer.

  8. A one year experience with the multislice helical CT.

    PubMed

    Rigauts, H

    1999-12-01

    New detector morphology and increased computer power have led to a second leap in CT technology. With multislice helical CT, four slices per rotation are reconstructed resulting in a 3 to 6 times reduction of the examination time. During our one-year experience with the multislice CT, we have learnt that the major advantage of the technique is the possibility to cover a large volume with thin slices. Combination of both makes it possible to scan an entire anatomic region during the optimal enhancement phase (after i.v. contrast injection) with a high spatial resolution. New diagnostic possibilities can be explored by CT together with improved and more detailed post-processing tools.

  9. CEnPiT: Helical cardiac CT reconstruction

    SciTech Connect

    Bontus, Claas; Koken, Peter; Koehler, Thomas; Grass, Michael

    2006-08-15

    Computer tomography (CT) scanners with an increasing number of detector rows offer the potential of shorter scanning times. Nevertheless, the reconstruction problem becomes more challenging, since cone beam artifacts are likely to enter. Here, we consider helical cardiac CT. We analyze how a relationship can be established between exact reconstruction algorithms and the demand to perform a cardiac gating. Utilizing the redundancies requires the consideration of all kinds of Radon planes. For the reconstruction algorithm proposed here, we separate the data into two parts. The first part contains contributions of Radon planes, which are measured with a large number of redundancies. The second part contains the remaining contributions. As it turns out, the second part contributes rather to the low-frequency contents of trans-axial slices. Therefore, we propose to perform a gated back-projection only for the first part, while the second part is back-projected in an ungated way. Data from the complete source trajectory are employed in the reconstruction process in contrary to conventional helical cardiac reconstruction methods. Moreover, all different types of Radon planes are taken into account in the reconstruction, though an ECG-dependent cardiac gating is applied. The reconstruction results, which we present for clinical and simulated data, demonstrate the high potential of CEnPiT for helical cardiac CT with large cone angle systems.

  10. Pediatric organ dose measurements in axial and helical multislice CT

    SciTech Connect

    McDermott, Alanna; White, R. Allen; Mc-Nitt-Gray, Mike; Angel, Erin; Cody, Dianna

    2009-05-15

    An anthropomorphic pediatric phantom (5-yr-old equivalent) was used to determine organ doses at specific surface and internal locations resulting from computed tomography (CT) scans. This phantom contains four different tissue-equivalent materials: Soft tissue, bone, brain, and lung. It was imaged on a 64-channel CT scanner with three head protocols (one contiguous axial scan and two helical scans [pitch=0.516 and 0.984]) and four chest protocols (one contiguous axial scan and three helical scans [pitch=0.516, 0.984, and 1.375]). Effective mA s [=(tube currentxrotation time)/pitch] was kept nearly constant at 200 effective mA s for head and 290 effective mA s for chest protocols. Dose measurements were acquired using thermoluminescent dosimeter powder in capsules placed at locations internal to the phantom and on the phantom surface. The organs of interest were the brain, both eyes, thyroid, sternum, both breasts, and both lungs. The organ dose measurements from helical scans were lower than for contiguous axial scans by 0% to 25% even after adjusting for equivalent effective mA s. There was no significant difference (p>0.05) in organ dose values between the 0.516 and 0.984 pitch values for both head and chest scans. The chest organ dose measurements obtained at a pitch of 1.375 were significantly higher than the dose values obtained at the other helical pitches used for chest scans (p<0.05). This difference was attributed to the automatic selection of the large focal spot due to a higher tube current value. These findings suggest that there may be a previously unsuspected radiation dose benefit associated with the use of helical scan mode during computed tomography scanning.

  11. Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination.

    PubMed

    Rao, P M; Rhea, J T; Novelline, R A; McCabe, C J; Lawrason, J N; Berger, D L; Sacknoff, R

    1997-01-01

    To evaluate a focused, helical computed tomographic (CT) technique for imaging the appendix in patients suspected of having appendicitis. One hundred patients prospectively underwent appendix CT examination, with use of oral and colon contrast media and contiguous, thin-collimation, helical CT imaging of the right lower quadrant. Results were correlated with the results of surgery and pathologic examination from 61 patients or from clinical follow-up in 39 patients. CT scans were positive for appendicitis in 59 patients: true-positive in 56 patients on the basis of surgery and pathologic examination, and false-positive in two patients on the basis of clinical follow-up; in the case of the other positive scan, the clinical outcome was indeterminate. CT scans were negative for appendicitis in 41 patients: true-negative in five patients on the basis of surgery and pathologic examination, and true-negative in 36 patients on the basis of clinical follow-up. CT had a sensitivity of 100%, a specificity of 95%, a positive predictive value of 97%, a negative predictive value of 100%, and an accuracy of 98%. The normal appendix was always identified. CT helped establish alternative diagnoses in 33 of the 41 patients (80%) in whom the results of CT were negative for appendicitis. Appendix CT examination can help diagnose or exclude appendicitis and establish an alternative diagnosis.

  12. Helical CT study of cerebral perfusion and related hemodynamic parameters

    NASA Astrophysics Data System (ADS)

    Cenic, Aleksa; Lee, Ting-Yim; Craen, Rosemary A.; Gelb, Adrian W.

    1997-05-01

    A convenient method for assessing cerebral perfusion and related functional parameters has been developed using a third generation slip-ring CT scanner. Dynamic contrast- enhanced scanning at the same level was employed to image the cerebral circulation at the rate of 1 image per second. Using data acquired with this non-helical mode of scanning, we have developed a method for the simultaneous in-vivo determination of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). These measurements are given in the same physiological units as positron emission tomography. In order to obtain accurate measurements of these parameters, methods were also developed to correct for recirculation and partial volume averaging in imaging small blood vessels. We have used 6 New Zealand white rabbits in our studies. For each rabbit, up to 3 CT measurements of CBF, CBV, and MTT were made at normocapnia under isoflurane anesthesia. Coronal sections through the brain were imaged while simultaneously imaging either a brain artery or the ear artery. Images were acquired for 1 minute as Isovue 300 was injected intravenously. In the acquired CT images, regions of interest in brain parenchyma and an artery were drawn. For each region of interest, the mean CT number in pre-contrast images was subtracted from the mean in post-contrast images to calculate the contrast concentration curves for the brain regions Q(t) and the arterial region Ca(t). Using a robust deconvolution method, the MTT was determined. CBV was then determined from the ratio of the areas of Q(t) and Ca(t). Finally, CBF was calculated from the Central Volume Principle. The mean regional CBF, CBV and MTT values were 73.3 +/- 5.1 ml/min/100g, 1.93 +/- 0.12 ml/100g and 1.80 +/- 0.18 s respectively. IN order to validate our CT CBF measurements, we also measured CBF using the well- established technique of microspheres with each CT study. The feasibility of our CT method to measure CBF accurately was

  13. Anti-aliasing weighting functions for multislice helical CT

    NASA Astrophysics Data System (ADS)

    La Riviere, Patrick J.; Pan, Xiaochuan

    2002-05-01

    We develop a new projection weighting function for interpolation and reconstruction of multi-slice helical computed tomography data with the hope of reducing longitudinal aliasing in reconstructed volumes. The weighting function is based on the application of the Papoulis generalized sampling theorem to the interlaced longitudinal samples acquired by the multi-slice scanner. We call the approach 180MAA, for multi-slice anti-aliasing. For pitch 3, the 180MAA approach yields high-quality images of the 3D Shepp-Logan phantom as well as a longitudinal MTF superior to that of the 180MLI approach, which is based on the use of linear interpolation. However, it is not as successful at mitigating aliasing as had been doped due to the presence of a significant and unexpected aliasing component that can be attributed to the small cone angle in multi-slice helical CT. The presence of this effect is interesting and significant in its own right, however.

  14. Helical CT combined with contrast material administered only through the colon for imaging of suspected appendicitis.

    PubMed

    Rao, P M; Rhea, J T; Novelline, R A; Mostafavi, A A; Lawrason, J N; McCabe, C J

    1997-11-01

    Helical CT combined with contrast material administered by mouth and through the colon has been shown to be accurate for appendiceal imaging. This investigation was performed to determine if helical CT combined with contrast material administered only through the colon has comparable accuracy. One hundred patients prospectively underwent appendiceal CT imaging with thin-collimation, helical scanning limited to the lower abdomen and upper pelvis after contrast material was administered only through the colon. CT results were correlated with surgical and pathologic findings at appendectomy (56 patients), other surgery (three patients), or clinical follow-up at least 2 months after the CT scan (41 patients). Fifty-three CT scans were interpreted as positive for appendicitis, including 52 true-positives (with surgical-pathologic correlation) and on false-positive (with clinical follow-up). Forty-seven CT scans were interpreted as negative for appendicitis, including 40 true-negatives with clinical follow-up, three true-negatives with appendectomy and pathologic correlation, three true-negatives with other surgery and pathologic correlation, and one false-negative with appendectomy and pathologic correlation. CT had a 98% sensitivity, 98% specificity, 98% positive predictive value, 98% negative predictive value, and 98% accuracy for diagnosing or excluding appendicitis. In 47 normal appendix cases at CT, the appendix was seen in 44 cases (94%), and an alternative diagnosis was identified in 29 cases (62%). For diagnosing appendicitis, helical CT combined with contrast material administered only through the colon proved to be as accurate (98%) as helical CT combined with contrast material administered by mouth and through the colon. Helical CT with contrast material administered only through the colon also could be performed immediately and without any of the potential patient risks or discomforts of contrast material administered i.v. or by mouth.

  15. Chronic inflammatory appendiceal conditions that mimic acute appendicitis on helical CT.

    PubMed

    Checkoff, Jaime L; Wechsler, Richard J; Nazarian, Levon N

    2002-09-01

    Acute appendicitis is commonly diagnosed on CT, but chronic appendiceal processes can mimic acute appendicitis. The purpose of this study was to identify the frequency of these alternative conditions and their findings on helical CT. Chronic inflammatory conditions other than acute appendicitis were found in 9% of patients who underwent surgery after CT findings were interpreted as suspicious for appendicitis. These inflammatory conditions were indistinguishable from acute appendicitis when we used either primary or secondary CT signs.

  16. Sampling and aliasing consequences of quarter-detector offset use in helical CT.

    PubMed

    La Rivière, Patrick J; Pan, Xiaochuan

    2004-06-01

    In this paper, the sampling and aliasing consequences of employing a quarter-detector-offset (QDO) in helical computed tomography (CT) are analyzed. QDO is often used in conventional CT to reduce in-plane aliasing by eliminating data redundancies to improve radial sampling. In helical CT, these same redundancies are exploited to improve longitudinal sampling and so it might seem ill-advised to employ QDO. The relative merit of the two geometries for helical CT is studied by conducting a multidimensional sampling analysis of projection-space sampling as well as a Fourier crosstalk analysis of crosstalk among the object's Fourier basis components. Both a standard fanbeam helical CT geometry and a hypothetical parallel-beam CT geometry, which helps illuminate the more complicated fanbeam results, are analyzed. Using the sampling analysis, it was found that the use of QDO leads to very different spectral tiling than arise when not using QDO. However, due to the shape of the essential support of the projection data spectra that arises in practice, both configurations lead to very similar or identical amounts of spectral overlap. This perspective also predicts the spatially variant longitudinal aliasing that has been observed in helical CT. The crosstalk results were consistent with those of the multidimensional sampling analysis. Thus, from the standpoint of aliasing and crosstalk, no compelling difference is found between the two geometries.

  17. Helical mode lung 4D-CT reconstruction using Bayesian model.

    PubMed

    He, Tiancheng; Xue, Zhong; Nitsch, Paige L; Teh, Bin S; Wong, Stephen T

    2013-01-01

    4D computed tomography (CT) has been widely used for treatment planning of thoracic and abdominal cancer radiotherapy. Current 4D-CT lung image reconstruction methods rely on respiratory gating to rearrange the large number of axial images into different phases, which may be subject to external surrogate errors due to poor reproducibility of breathing cycles. New image-matching-based reconstruction works better for the cine mode of 4D-CT acquisition than the helical mode because the table position of each axial image is different in helical mode and image matching might suffer from bigger errors. In helical mode, not only the phases but also the un-uniform table positions of images need to be considered. We propose a Bayesian method for automated 4D-CT lung image reconstruction in helical mode 4D scans. Each axial image is assigned to a respiratory phase based on the Bayesian framework that ensures spatial and temporal smoothness of surfaces of anatomical structures. Iterative optimization is used to reconstruct a series of 3D-CT images for subjects undergoing 4D scans. In experiments, we compared visually and quantitatively the results of the proposed Bayesian 4D-CT reconstruction algorithm with the respiratory surrogate and the image matching-based method. The results showed that the proposed algorithm yielded better 4D-CT for helical scans.

  18. Focal arterial injuries of the proximal extremities: helical CT arteriography as the initial method of diagnosis.

    PubMed

    Soto, J A; Múnera, F; Morales, C; Lopera, J E; Holguín, D; Guarín, O; Castrillón, G; Sanabria, A; García, G

    2001-01-01

    To present our experience with helical computed tomographic (CT) arteriography as the initial diagnostic examination in patients suspected to have focal arterial injuries of the proximal extremities. During 19 months, 142 arterial segments in the proximal portions of the extremities of 139 patients with trauma were evaluated with helical CT arteriography. CT arteriograms were interpreted on site by the radiologist in charge of emergency procedures and retrospectively with consensus interpretation between two radiologists. CT study quality and the presence of arterial injuries were noted. CT arteriographic findings were compared with those of surgery, conventional arteriography, and/or clinical follow-up. Five (3.6%) patients had nondiagnostic studies and underwent conventional arteriography. In the remaining 137 arterial segments in 134 patients, helical CT arteriography demonstrated arterial injuries in 61 segments and normal arteries in 76 segments. These segments were treated initially with surgery (55 segments) or endovascular intervention (four segments) or were observed (78 segments); 77 of the 78 observed segments remained stable at 3-18 months (mean follow-up, 5.2 months). There were no differences between the on-site and consensus interpretations (kappa = 1.0). The sensitivity of CT arteriography was 95.1%, and the specificity was 98.7%. Helical CT arteriography can be performed as the initial diagnostic method in most patients suspected to have focal arterial injuries of the proximal portions of the extremities.

  19. New barium paste mixture for helical (slip-ring) CT evaluation of rectal carcinoma.

    PubMed

    Ogawa, Y; Noda, Y; Nishioka, A; Inomata, T; Yoshida, S; Toki, T; Ogoshi, S; Ma, J

    1997-01-01

    We describe a new method for complete opacification of the rectum using helical CT and a newly developed anal contrast agent. Rectal cancers were easily identified in all of the 21 patients examined, and diagnostic accuracy in detecting local invasion was 94%. Our method of rectal CT is easy to perform and well tolerated.

  20. Single-slice reconstruction method for helical cone-beam differential phase-contrast CT.

    PubMed

    Fu, Jian; Chen, Liyuan

    2014-01-01

    X-ray phase-contrast computed tomography (PC-CT) can provide the internal structure information of biomedical specimens with high-quality cross-section images and has become an invaluable analysis tool. Here a simple and fast reconstruction algorithm is reported for helical cone-beam differential PC-CT (DPC-CT), which is called the DPC-CB-SSRB algorithm. It combines the existing CB-SSRB method of helical cone-beam absorption-contrast CT with the differential nature of DPC imaging. The reconstruction can be performed using 2D fan-beam filtered back projection algorithm with the Hilbert imaginary filter. The quality of the results for large helical pitches is surprisingly good. In particular, with this algorithm comparable quality is obtained using helical cone-beam DPC-CT data with a normalized pitch of 10 to that obtained using the traditional inter-row interpolation reconstruction with a normalized pitch of 2. This method will push the future medical helical cone-beam DPC-CT imaging applications.

  1. Helical CT with only colonic contrast material for diagnosing diverticulitis: prospective evaluation of 150 patients.

    PubMed

    Rao, P M; Rhea, J T; Novelline, R A; Dobbins, J M; Lawrason, J N; Sacknoff, R; Stuk, J L

    1998-06-01

    We prospectively evaluated a helical CT technique in which contrast material is administered only through the colon for the imaging of suspected diverticulitis. One hundred fifty consecutive patients who presented to our emergency department with clinically suspected diverticulitis underwent helical abdominal CT after contrast material was administered only through the colon. CT findings of diverticulitis included diverticula, muscular wall hypertrophy, focal colonic wall thickening, and pericolonic fat stranding. CT results were correlated with clinical follow-up (all patients) and with pathologic findings (41 patients). A final clinical diagnosis of diverticulitis was made in 64 patients (43%), of whom 62 (97%) had CT results positive for diverticulitis. Of the 86 patients for whom diverticulitis was clinically excluded, all (100%) had CT results that were negative for diverticulitis. CT interpretations had a sensitivity of 97%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 98%, and an overall accuracy of 99%. Alternative diagnoses were noted on CT in 50 (58%) of 86 patients who did not have diverticulitis and included 50 (78%) of the 64 patients in whom an alternative condition other than nonspecific abdominal pain was established. Helical CT obtained after contrast material administered only through the colon is accurate (99%) for confirming or excluding clinically suspected diverticulitis and for suggesting alternative conditions (78%) when they are present. This CT technique avoids the risks, discomforts, and costs of oral and i.v. contrast material administration and allows immediate scanning.

  2. Cervical spine evaluation in urban trauma centers: lowering institutional costs and complications through helical CT scan.

    PubMed

    Grogan, Eric L; Morris, John A; Dittus, Robert S; Moore, Derek E; Poulose, Benjamin K; Diaz, Jose J; Speroff, Theodore

    2005-02-01

    In the evaluation of the cervical spine (c-spine), helical CT scan has higher sensitivity and specificity than plain radiographs in the moderate- and high-risk trauma population, but is more costly. We hypothesize that institutional costs associated with missed injuries make helical CT scan the least costly approach. A cost-minimization study was performed using decision analysis examining helical CT scan versus radiographic evaluation of the c-spine. Parameter estimates were obtained from the literature for probability of c-spine injury, probability of paralysis after missed injury, plain film sensitivity and specificity, CT scan sensitivity and specificity, and settlement cost of missed injuries resulting in paralysis. Institutional costs of CT scan and plain radiography were used. Sensitivity analyses tested robustness of strategy preference, accounted for parameter variability, and determined threshold values for individual parameters on strategy preference. C-spine evaluation with helical CT scan has an expected cost of US 554 dollars per patient compared with US 2,142 dollars for plain films. CT scan is the least costly alternative if threshold values exceed US 58,180 dollars for institutional settlement costs, 0.9% for probability of c-spine fracture, and 1.7% for probability of paralysis. Plain films are least costly if CT scan costs surpass US 1,918 dollars or plain film sensitivity exceeds 90%. Helical CT scan is the preferred initial screening test for detection of cervical spine fractures among moderate- to high-risk patients seen in urban trauma centers, reducing the incidence of paralysis resulting from false-negative imaging studies and institutional costs, when settlement costs are taken into account.

  3. An iterative reconstruction method for high-pitch helical luggage CT

    NASA Astrophysics Data System (ADS)

    Xue, Hui; Zhang, Li; Chen, Zhiqiang; Jin, Xin

    2012-10-01

    X-ray luggage CT is widely used in airports and railway stations for the purpose of detecting contrabands and dangerous goods that may be potential threaten to public safety, playing an important role in homeland security. An X-ray luggage CT is usually in a helical trajectory with a high pitch for achieving a high passing speed of the luggage. The disadvantage of high pitch is that conventional filtered back-projection (FBP) requires a very large slice thickness, leading to bad axial resolution and helical artifacts. Especially when severe data inconsistencies are present in the z-direction, like the ends of a scanning object, the partial volume effect leads to inaccuracy value and may cause a wrong identification. In this paper, an iterative reconstruction method is developed to improve the image quality and accuracy for a large-spacing multi-detector high-pitch helical luggage CT system. In this method, the slice thickness is set to be much smaller than the pitch. Each slice involves projection data collected in a rather small angular range, being an ill-conditioned limited-angle problem. Firstly a low-resolution reconstruction is employed to obtain images, which are used as prior images in the following process. Then iterative reconstruction is performed to obtain high-resolution images. This method enables a high volume coverage speed and a thin reconstruction slice for the helical luggage CT. We validate this method with data collected in a commercial X-ray luggage CT.

  4. [Prognostic significance of helical CT in patients with destructive pancreatitis].

    PubMed

    Bulanova, T V

    2000-01-01

    Spiral scanning computed tomography (CT) is able not only to image the pancreas and to evaluate its structure, but to interpret the status of the adjacent organs and tissues. CT symptoms of pancreatic necrotic changes and multiorgan failure were studied in the prospective follow-up of 47 patients with prior destructive pancreatitis (158 studies). CT differentially substantiated indications for choosing treatment policy for different forms of pancreatic lesions. The paper gives a quantitative assessment of necrotic pancreatic parencymatous areas and shows its prognostic value.

  5. Acute cholecystitis: quantitative and qualitative evaluation with 64-section helical CT.

    PubMed

    Soyer, Philippe; Hoeffel, Christine; Dohan, Anthony; Gayat, Etienne; Eveno, Clarisse; Malgras, Brice; Pautrat, Karine; Boudiaf, Mourad

    2013-06-01

    Because of an expanded role for CT in the evaluation of patients with acute abdominal pain, it is not rare that acute cholecystitis is depicted by CT. However, the sensitivity and the specificity of a given CT variable for the diagnosis of acute cholecystitis is not known. To quantitatively and qualitatively analyze acute cholecystitis at 64-section helical CT with submilimeter and isotropic voxels using a retrospective case-control study. The 64-section helical CT examinations obtained with submilimeter and isotropic voxels in 40 patients with acute cholecystitis (25 men; mean age, 62.2 years) were quantitatively and qualitatively analyzed and compared to those of 40 control subjects matched for age and gender. Receiver-operating characteristic (ROC) curve analysis was used to determine the most discriminating cut-off values for quantitative variables. Comparisons of qualitative variables were made using univariate analysis. Pericholecystic fat stranding, mural stratification, pericholecystic hypervascularity, spontaneous hyperattenuation of gallbladder wall, short (≥ 32-mm) and long (≥ 74-mm) gallbladder axis enlargement, and gallbladder wall thickening (≥ 3.6-mm) were the most discriminating and independent variables for the diagnosis of acute cholecystitis (P < 0.0001). Using cut-off values found at ROC curve analysis, gallbladder wall thickening, and short and long gallbladder axis enlargement were the most sensitive findings (sensitivity = 92.5%; 95%CI: 79.6%-98.4%) for the diagnosis of acute cholecystitis. Acute cholecystitis is associated with myriad suggestive findings on 64-section helical CT. It can be anticipated that familiarity with these findings would result in more confident diagnosis of acute cholecystitis at 64-section helical CT. © 2013 The Foundation Acta Radiologica.

  6. Computed tomography (CT) of the lungs of the dog using a helical CT scanner, intravenous iodine contrast medium and different CT windows.

    PubMed

    Cardoso, L; Gil, F; Ramírez, G; Teixeira, M A; Agut, A; Rivero, M A; Arencibia, A; Vázquez, J M

    2007-10-01

    The aim of this study was to determine the accuracy of helical computed tomography (CT) for visualizing pulmonary parenchyma and associated formations in normal dogs. CT scan was performed by using intravenous contrast medium and by applying different types of CT windows: soft tissue and lung windows, and high-resolution computed tomography of the lung. This technique allowed, especially with lung window types, a good view of the parenchyma, bronchial tree, vascular structures and pleural cavity. The selected images, with high anatomical quality and tissue contrast, may be a reference for future clinical studies of this organ. Thus, helical CT is a promising non-invasive method of diagnosing a wide variety of pulmonary diseases in dogs.

  7. Sensitivity and specificity of the individual CT signs of appendicitis: experience with 200 helical appendiceal CT examinations.

    PubMed

    Rao, P M; Rhea, J T; Novelline, R A

    1997-01-01

    Our goal was to determine the sensitivity, specificity, and diagnostic value of individual signs at helical appendiceal CT. Two hundred helical appendiceal CT scans (100 appendicitis and 100 normal appendix cases) were interpreted for individual signs of appendicitis. Scan findings were correlated with appendectomy or clinical follow-up results. Individual CT signs identified and their sensitivity and specificity, respectively, included fat stranding (100%, 80%), enlarged (> 6 mm) unopacified appendix (93%, 100%), focal cecal apical thickening (69%, 100%), adenopathy (62%, 66%), appendolith(s) (44%, 100%), arrowhead sign (23%, 100%), paracolic gutter fluid (18%, 86%), abscess (11%, 100%), cecal bar (10%, 100%), extraluminal air (8%, 97%), phlegmon (7%, 99%), ileal (3%, 86%) or sigmoid (3%, 95%) wall thickening, and diffuse cecal wall thickening (0%, 91%). Individual appendiceal CT signs of appendicitis vary in sensitivity, specificity, and thus diagnostic value. An enlarged appendix with periappendiceal fat stranding occurs in 93% of appendicitis CT cases. Less common but specific signs [cecal apical changes, appendolith(s) are usually present in the remaining appendicitis cases. Some signs seen with appendicitis (adenopathy, fat stranding, adjacent bowel wall thickening, fluid) can also be noted with alternative conditions, and in these cases normal appendix identification is the key to excluding appendicitis.

  8. Diagnosis of arterial injuries caused by penetrating trauma to the neck: comparison of helical CT angiography and conventional angiography.

    PubMed

    Múnera, F; Soto, J A; Palacio, D; Velez, S M; Medina, E

    2000-08-01

    To determine the sensitivity and specificity of helical computed tomographic (CT) angiography in the diagnosis of carotid and vertebral arterial injuries caused by penetrating neck trauma. A prospective study was conducted during 24 months in 60 patients with penetrating neck trauma who were referred for conventional angiography owing to clinical suspicion of arterial injury. In the patient population, 146 arteries (77 carotid, 69 vertebral) were studied by means of conventional angiography. In all patients, conventional angiography and helical CT angiography were completed within 6 hours. Two radiologists interpreted helical CT angiographic studies by means of consensus. Conventional angiography was the standard of reference for determining the sensitivity and specificity of helical CT angiography. Conventional angiograms showed arterial injuries in 10 (17%) of 60 patients. Conventional angiographic findings were arterial occlusion (n = 4), arteriovenous fistula (n = 2), pseudoaneurysm (n = 3), pseudoaneurysm with arteriovenous fistula (n = 1), and normal arteries (n = 136). Nine of 10 arterial injuries and all normal arteries were depicted adequately at helical CT angiography. Sensitivity of helical CT angiography was 90%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 98%. The sensitivity and specificity of helical CT angiography are high for detection of major carotid and vertebral arterial injuries resulting from penetrating trauma.

  9. "Ovarian vascular pedicle" sign revealing organ of origin of a pelvic mass lesion on helical CT.

    PubMed

    Lee, Jong Hwa; Jeong, Yoong Ki; Park, Ji Kang; Hwang, Jae Choel

    2003-07-01

    We evaluated the "ovarian vascular pedicle" sign as a way of differentiating ovarian from subserosal uterine lesions on single-detector helical CT. We prospectively evaluated 131 patients who had a pelvic mass suspected of originating in the ovary or subserosal zone of the uterus and had undergone helical CT before surgery. A total of 108 ovarian lesions and 23 subserosal uterine myomas were confirmed. CT images were analyzed prospectively by consensus of two radiologists who thoroughly evaluated the retrograde tracing of the gonadal veins to the ovary or pelvic mass. To assess the value of analyzing the ovarian vascular pedicle sign in identifying the organ of origin of a pelvic mass, we compared statistical proportions for the frequencies of the sign in ovarian tumors and subserosal uterine myomas by performing the chi-square test. The probabilities for the presence of the ovarian vascular pedicle sign as a positive finding for a pelvic mass of ovarian origin were calculated. The presence of the ovarian vascular pedicle sign was identified in 92% (99/108) of ovarian masses and in 13% (3/23) of subserosal uterine myomas. The sign was statistically significant (p < 0.01) for differentiating a mass of ovarian origin from a mass of subserosal uterine origin. When the ovarian vascular pedicle sign on helical CT confirmed the ovarian origin, the sensitivity, specificity, positive predictive value and negative predictive value, and diagnostic accuracy were 92% (99/108), 87% (20/23), 97% (99/102), 69% (20/29), and 91% (119/131), respectively. The presence of the ovarian vascular pedicle sign on helical CT is valuable for confirming the ovarian origin of a pelvic tumor and for differentiating an ovarian tumor from subserosal uterine myoma.

  10. [Ultra-low-dose spiral (helical) CT of the thorax: a filtering technique].

    PubMed

    Nitta, N; Takahashi, M; Murata, K; Mori, M; Shimoyama, K; Mishina, A; Matsuo, H; Morita, R; Sugii, K; Nomura, A

    1996-01-01

    To reduce the radiation dose from spiral (helical) CT, a custom-made aluminium filter was installed in the X-ray tube and a reduction of effective tube current was attempted. A pronounced reduction of effective tube current, namely, 6 and 3 mA, was achieved with 26 and 37 mm thick aluminium filters, respectively. Visualization of normal lung structure was accomplished with both 6 and 3 mA settings. However, images of 3 mA failed to delineate mediastinal structures because of marked beam hardening resulting from the bone structure of the thoracic inlet. Six mA was considered the lowest dose setting of spiral (helical) CT of the thorax that could be used for lung cancer screening.

  11. New barium paste mixture for helical (slip-ring) CT evaluation of the esophagus.

    PubMed

    Noda, Y; Ogawa, Y; Nishioka, A; Inomata, T; Yoshida, S; Toki, T; Ogoshi, S; Ma, J

    1996-01-01

    Successful opacification of the lumen of the esophagus with cancer or paraesophageal diseases has not yet been fully achieved. Therefore, we have recently adopted a new method for complete and continuous opacification of the whole thoracic esophagus using our newly developed oral contrast agent with a helical (slip-ring) CT scanner. The agent consists of 3.6 (wt/vol)% carboxy-methyl cellulose sodium paste containing 2 (wt/vol)% barium sulfate. The results indicate that almost complete and continuous opacification of esophageal lumen was achieved. Our new method of esophageal CT is easy to perform and was well tolerated by patients, being therefore ideal for routine examinations.

  12. Pitfalls in image reconstruction of helical CT angiography: an experimental study.

    PubMed

    Ogata, I; Yamashita, Y; Sumi, S; Nishiharu, T; Mitsuzaki, K; Takahashi, M

    1999-01-01

    This study was undertaken to evaluate the effects of the object related factors: background tissue and the direction of vessels on the morphological reproducibility of helical CT angiography. Cylindrical tubes filled with a diluted contrast medium were prepared to obtain vascular phantoms. The scan was performed within various background tissues. For the evaluation of the direction of the vessels, two types of vascular phantoms were prepared. The phantoms were scanned by varying beam collimations and scan pitches. Reconstructed CT images were markedly affected by the background tissue. The reconstructed images were also affected by the direction of vessels.

  13. Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities.

    PubMed

    Soto, J A; Múnera, F; Cardoso, N; Guarín, O; Medina, S

    1999-01-01

    The purpose of this work was to assess the performance of helical CT angiography (CTA) in the diagnosis of injuries to large arteries of the extremities. We performed helical CTA on 45 consecutive patients referred for conventional angiography for evaluation of suspected arterial injuries after sustaining trauma to the extremities (13 upper, 32 lower). Two radiologists interpreted the helical CTA studies independently. Diagnostic performance parameters evaluated included sensitivity, specificity, receiver operating characteristic (ROC) curves, and interobserver agreement (kappa statistics). Conventional angiography was used as the standard of reference for determination of final diagnoses. Forty-three of 45 patients (96%) had diagnostic helical CTA examinations. Final diagnoses in these 43 patients were arterial occlusion (n = 7), partial obstruction (n = 3), pseudoaneurysm (n = 5), arteriovenous fistula (n = 1), pseudoaneurysm and arteriovenous fistula (n = 3), and normal findings (n = 24). Sensitivity and specificity were 90% [95% confidence interval (CI), 80-99] and 100% (95% CI, 99-100), respectively, for Reader 1 and 100% (95% CI, 99-100) and 100% (95% CI, 99-100), respectively, for Reader 2. ROC curve analysis revealed high diagnostic performance, with areas under the curve of >0.9 for both readers. Interobserver agreement was 0.9. The diagnostic performance of helical CTA for detection of major injuries of large arteries of the extremities is high.

  14. Objective performance evaluation methods adapted to helical and multislice CT scanners

    NASA Astrophysics Data System (ADS)

    Ellerbusch, David C.

    Since its introduction in the early 1970's, Computed Tomography (CT) has evolved into an important imaging tool for a continually increasing variety of clinical applications. This growth is due to dramatic improvements in image quality and acquisition speed over the last sixteen years. These improvements have come from important technical developments that include sub-second gantry rotation times, helical scanning, multislice acquisition, and tube current modulation. The procedures for performing CT scanner evaluations have been in existence since the 1970's, but most are based on single-slice, axial scan geometry. These procedures are not adequate for the evaluation of modern, helical multislice scanners that use fundamentally different acquisition geometries, have many types of acquisition modes available, and are capable of generating huge numbers of images in a short period of time. Properly evaluating the image quality of these scanners is usually too difficult and time-consuming using the more traditional test methods. Computer analysis methods are needed to analyze the large number of images generated during a CT scanner evaluation. Subjecting these images to objective image evaluation methods will provide a much more thorough evaluation of image quality compared to subjective methods, and can do so in a shorter amount of time. This dissertation describes the development of objective analysis methods and improved phantom designs that more accurately and efficiently evaluate the image quality in helical multislice CT scanners. The new tools are appropriate for routine quality assurance, for acceptance testing of new equipment, and for optimizing techniques for novel clinical applications. Furthermore, using these methods we have found deficiencies and errors in the design of specific CT scanner models and also significant problems in the performance of individual scanner.

  15. WE-G-18A-06: Sinogram Restoration in Helical Cone-Beam CT

    SciTech Connect

    Little, K; Riviere, P La

    2014-06-15

    Purpose: To extend CT sinogram restoration, which has been shown in 2D to reduce noise and to correct for geometric effects and other degradations at a low computational cost, from 2D to a 3D helical cone-beam geometry. Methods: A method for calculating sinogram degradation coefficients for a helical cone-beam geometry was proposed. These values were used to perform penalized-likelihood sinogram restoration on simulated data that were generated from the FORBILD thorax phantom. Sinogram restorations were performed using both a quadratic penalty and the edge-preserving Huber penalty. After sinogram restoration, Fourier-based analytical methods were used to obtain reconstructions. Resolution-variance trade-offs were investigated for several locations within the reconstructions for the purpose of comparing sinogram restoration to no restoration. In order to compare potential differences, reconstructions were performed using different groups of neighbors in the penalty, two analytical reconstruction methods (Katsevich and single-slice rebinning), and differing helical pitches. Results: The resolution-variance properties of reconstructions restored using sinogram restoration with a Huber penalty outperformed those of reconstructions with no restoration. However, the use of a quadratic sinogram restoration penalty did not lead to an improvement over performing no restoration at the outer regions of the phantom. Application of the Huber penalty to neighbors both within a view and across views did not perform as well as only applying the penalty to neighbors within a view. General improvements in resolution-variance properties using sinogram restoration with the Huber penalty were not dependent on the reconstruction method used or the magnitude of the helical pitch. Conclusion: Sinogram restoration for noise and degradation effects for helical cone-beam CT is feasible and should be able to be applied to clinical data. When applied with the edge-preserving Huber penalty

  16. Helical CT and three-dimensional CT of facial and orbital injury.

    PubMed

    Rhea, J T; Rao, P M; Novelline, R A

    1999-05-01

    Knowledge of the regions of the face and their buttresses and knowledge of the types of facial injuries frequently encountered simplifies the diagnostic task. The indications for CT include detection of suspected fractures and preoperative planning. The cost of facial CT to the hospital has declined and is little different than the cost of plain films. CT may become the screening modality of choice depending on the cost structure at any given hospital.

  17. Correction for human head motion in helical x-ray CT

    NASA Astrophysics Data System (ADS)

    Kim, J.-H.; Sun, T.; Alcheikh, A. R.; Kuncic, Z.; Nuyts, J.; Fulton, R.

    2016-02-01

    Correction for rigid object motion in helical CT can be achieved by reconstructing from a modified source-detector orbit, determined by the object motion during the scan. This ensures that all projections are consistent, but it does not guarantee that the projections are complete in the sense of being sufficient for exact reconstruction. We have previously shown with phantom measurements that motion-corrected helical CT scans can suffer from data-insufficiency, in particular for severe motions and at high pitch. To study whether such data-insufficiency artefacts could also affect the motion-corrected CT images of patients undergoing head CT scans, we used an optical motion tracking system to record the head movements of 10 healthy volunteers while they executed each of the 4 different types of motion (‘no’, slight, moderate and severe) for 60 s. From these data we simulated 354 motion-affected CT scans of a voxelized human head phantom and reconstructed them with and without motion correction. For each simulation, motion-corrected (MC) images were compared with the motion-free reference, by visual inspection and with quantitative similarity metrics. Motion correction improved similarity metrics in all simulations. Of the 270 simulations performed with moderate or less motion, only 2 resulted in visible residual artefacts in the MC images. The maximum range of motion in these simulations would encompass that encountered in the vast majority of clinical scans. With severe motion, residual artefacts were observed in about 60% of the simulations. We also evaluated a new method of mapping local data sufficiency based on the degree to which Tuy’s condition is locally satisfied, and observed that areas with high Tuy values corresponded to the locations of residual artefacts in the MC images. We conclude that our method can provide accurate and artefact-free MC images with most types of head motion likely to be encountered in CT imaging, provided that the motion can

  18. Hepatocellular nodules in liver cirrhosis: state of the art CT evaluation (perfusion CT/volume helical shuttle scan/dual-energy CT, etc.).

    PubMed

    Okada, Masahiro; Kim, Tonsok; Murakami, Takamichi

    2011-06-01

    The purpose of this article is to explain the role of advanced liver CT imaging, including perfusion CT, dual-energy CT, and volume helical shuttle (VHS) scanning, with regard to its clinical applications. Perfusion CT is a promising method for calculating hepatic blood flow and portal blood flow, including microcirculation, using a color-encoded display of parameters obtained from the liver time-density curve, with iodine contrast agent. Tumor angiogenesis and assessment of the response to antiangiogenesis treatment (e.g., Sorafenib) can be analyzed by perfusion CT of the liver. VHS scan has very high temporal resolution due to the reciprocating movement employed during scanning, enabling the acquisition of 24 scans of the whole liver in the arterial dominant phase during a 40-s breath hold, and a reduction in radiation dose. Dual-energy CT enables differentiation of materials and tissues based on their CT density values, using two different energy spectra. This method includes a low tube voltage CT technique that increases the contrast enhancement of vascular structures while simultaneously reducing radiation dose. Images obtained at the preferred settings of low tube voltage and high tube current, with dose reduction in the hepatic arterial phase, are useful for detecting hypervascular hepatocellular carcinoma.

  19. Helical hydro-CT for diagnosis and staging of gastric carcinoma.

    PubMed

    Düx, M; Richter, G M; Hansmann, J; Kuntz, C; Kauffmann, G W

    1999-01-01

    The purpose of this work was to define the accuracy of helical hydro-CT (HHCT) in the diagnosis and staging of gastric carcinoma. One hundred twelve patients with gastric carcinoma were preoperatively imaged by HHCT. Gastric distension was achieved by ingestion of up to 1,500 ml of water. Bolus tracking was performed, and peristalsis was minimized by intravenously administered spasmolytics. Contrast material was then injected, and helical scanning was performed at the time of peak enhancement of the liver. CT images were analyzed for tumor infiltration of the gastric wall, and TNM staging criteria were applied according to the International Union Against Cancer (UICC) classification. The results were correlated with histopathologic findings. One hundred two of 115 (89%) gastric carcinomas were correctly diagnosed by HHCT. Small malignant ulcers (< or =2 cm) that corresponded to early gastric carcinoma were not visible on CT scans. T and N staging accuracies were 51% each; abdominal M staging was correct in 79% of all cases. The positive and negative predictive values of HHCT to foresee curative resection of gastric carcinoma were 75 and 84%, respectively. Mural thickening as well as marked contrast enhancement of the gastric wall are firmly related to gastric carcinoma. The accuracy of HHCT is acceptable for M staging but inadequate for local staging of gastric carcinoma. Nonetheless, HHCT is a useful guide for choosing between tumor resection and nonoperative treatment of patients. We therefore recommend HHCT as the method of choice for preoperative imaging of gastric carcinoma.

  20. Combined magnetic resonance urography and targeted helical CT in patients with renal colic: a new approach to reduce delivered dose.

    PubMed

    Blandino, Alfredo; Minutoli, Fabio; Scribano, Emanuele; Vinci, Sergio; Magno, Carlo; Pergolizzi, Stefano; Settineri, Nicola; Pandolfo, Ignazio; Gaeta, Michele

    2004-08-01

    To determine whether magnetic resonance urography (MRU), obtained before helical computed tomography (CT) in patients with acute renal colic, can help delimit the obstructed area to be subsequently examined by a targeted CT scan, thus reducing the dose of radiation. Patients (51) with symptoms of acute renal colic underwent MRU and a total urinary tract helical CT. CT images from the 5 cm below the level of ureteral obstruction as demonstrated by MRU were selected out. Combined interpretation of MRU and selected CT images constituted protocol A. Protocol B consisted of the entire unenhanced helical CT of the urinary tract. The two protocols were compared regarding the following points: 1) sensitivity in diagnosing the presence of obstructing urinary stones, and 2) the delivered radiation dose. Protocol A and protocol B had, respectively, 98% and 100% sensitivity in demonstrating ureteral stone as a cause of renal colic. Estimated average dose calculated from phantom study was 0.52 mSv for protocol A and 2.83 mSv for protocol B. Therefore, the effective radiation dose was 5.4 times lower in protocol A compared to protocol B. Combined MRU and short helical CT has a high sensitivity in detecting ureteral calculi with a reduced radiation dose. Copyright 2004 Wiley-Liss, Inc.

  1. Sampling conditions of 3D parallel and fan-beam x-ray CT with application to helical tomography

    NASA Astrophysics Data System (ADS)

    Desbat, Laurent; Roux, Sébastien; Grangeat, Pierre; Koenig, Anne

    2004-06-01

    We give the sampling conditions of the 3D fan-beam x-ray transform (3DFBXRT). The motivation of this work lies in the fact that helical tomography with a single detector line is simply a sampling of this transform under the helical constraint. We give a precise description of the geometry of the essential support of the 3DFBXRT Fourier transform and show how to derive efficient sampling schemes. We then give efficient sampling schemes in parallel helical tomography. We present numerical experiments showing that efficient sampling on hexagonal interlaced schemes yields better reconstructions than the standard schemes in both parallel helical tomography (using QDO) and 3DFBXRT. We discuss the practical drawbacks and advantages of these efficient schemes and the possible extension to fan-beam helical CT.

  2. Sampling conditions of 3D parallel and fan-beam x-ray CT with application to helical tomography.

    PubMed

    Desbat, Laurent; Roux, Sébastien; Grangeat, Pierre; Koenig, Anne

    2004-06-07

    We give the sampling conditions of the 3D fan-beam x-ray transform (3DFBXRT). The motivation of this work lies in the fact that helical tomography with a single detector line is simply a sampling of this transform under the helical constraint. We give a precise description of the geometry of the essential support of the 3DFBXRT Fourier transform and show how to derive efficient sampling schemes. We then give efficient sampling schemes in parallel helical tomography. We present numerical experiments showing that efficient sampling on hexagonal interlaced schemes yields better reconstructions than the standard schemes in both parallel helical tomography (using QDO) and 3DFBXRT. We discuss the practical drawbacks and advantages of these efficient schemes and the possible extension to fan-beam helical CT.

  3. Schedule for CT image guidance in treating prostate cancer with helical tomotherapy

    PubMed Central

    Beldjoudi, G; Yartsev, S; Bauman, G; Battista, J; Van Dyk, J

    2010-01-01

    The aim of this study was to determine the effect of reducing the number of image guidance sessions and patient-specific target margins on the dose distribution in the treatment of prostate cancer with helical tomotherapy. 20 patients with prostate cancer who were treated with helical tomotherapy using daily megavoltage CT (MVCT) imaging before treatment served as the study population. The average geometric shifts applied for set-up corrections, as a result of co-registration of MVCT and planning kilovoltage CT studies over an increasing number of image guidance sessions, were determined. Simulation of the consequences of various imaging scenarios on the dose distribution was performed for two patients with different patterns of interfraction changes in anatomy. Our analysis of the daily set-up correction shifts for 20 prostate cancer patients suggests that the use of four fractions would result in a population average shift that was within 1 mm of the average obtained from the data accumulated over all daily MVCT sessions. Simulation of a scenario in which imaging sessions are performed at a reduced frequency and the planning target volume margin is adapted provided significantly better sparing of organs at risk, with acceptable reproducibility of dose delivery to the clinical target volume. Our results indicate that four MVCT sessions on helical tomotherapy are sufficient to provide information for the creation of personalised target margins and the establishment of the new reference position that accounts for the systematic error. This simplified approach reduces overall treatment session time and decreases the imaging dose to the patient. PMID:19505966

  4. Computer-aided diagnosis workstation and database system for chest diagnosis based on multi-helical CT images

    NASA Astrophysics Data System (ADS)

    Satoh, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru; Sasagawa, Michizou

    2006-03-01

    Multi-helical CT scanner advanced remarkably at the speed at which the chest CT images were acquired for mass screening. Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router and Biometric fingerprint authentication system and Biometric face authentication system for safety of medical information. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system. The results of this study indicate that our computer-aided diagnosis workstation and network system can increase diagnostic speed, diagnostic accuracy and safety of medical information.

  5. Limited-angle reverse helical cone-beam CT for pipeline with low rank decomposition

    NASA Astrophysics Data System (ADS)

    Wu, Dong; Zeng, Li

    2014-10-01

    In this paper, tomographic imaging of pipeline in service by cone-beam computed tomography (CBCT) is studied. With the developed scanning strategy and image model, the quality of reconstructed image is improved. First, a limited-angle reverse helical scanning strategy based on C-arm computed tomography (C-arm CT) is developed for the projection data acquisition of pipeline in service. Then, an image model which considering the resemblance among slices of pipeline is developed. Finally, split Bregman method based algorithm is implemented in solving the model aforementioned. Preliminary results of simulation experiments show that the projection data acquisition strategy and reconstruction method are efficient and feasible, and our method is superior to Feldkamp-Davis-Kress (FDK) algorithm and simultaneous algebraic reconstruction technique (SART).

  6. Objective function to obtain multiple representative waveforms for a novel helical CT scan protocol

    PubMed Central

    Ruan, Dan; Thomas, David; Low, Daniel A.

    2015-01-01

    Purpose: To develop objective functions for selecting multiple representative respiratory waveforms. A specific application considered is to reduce the number of swiping scans in a novel helical CT scan protocol to harvest efficiency and dose reduction benefit. Methods: The authors consider a general class of potential objective functions consisting of weighted norms on pointwise profile differentials. The authors utilize the Lagrangian approach and derive proper conditions on the formulation based on first and second order optimality conditions. The derived objective functions are applied to clinically acquired respiratory trajectories for swipe subset selection to verify the validity and generality of the proposed rationale. An end-to-end 4DCT reconstruction comparison is performed using a swipe subset of data corresponding to 3 out of the full 25 waveforms to assess the consequence in image quality and dose. Results: Their results show that maximizing the proposed objective function with the suggested parameters yields maximal spread of trajectories among the selected subset. 4DCT Reconstruction using the chosen subset of data indicates the potential for further dose reduction by about 5 to 10 folds without significant sacrifice in image quality. Experimental results also support further generalization to include slice prioritization. Conclusions: The authors have derived a formulation that is both simple and general as a metric to quantify the spread of a set of respiratory trajectories, which can be used for subset selection with potential computation and dose reduction benefit when applied to a newly developed helical 4DCT scan protocol. PMID:25735271

  7. Sinogram restoration for ultra-low-dose x-ray multi-slice helical CT by nonparametric regression

    NASA Astrophysics Data System (ADS)

    Jiang, Lu; Siddiqui, Khan; Zhu, Bin; Tao, Yang; Siegel, Eliot

    2007-03-01

    During the last decade, x-ray computed tomography (CT) has been applied to screen large asymptomatic smoking and nonsmoking populations for early lung cancer detection. Because a larger population will be involved in such screening exams, more and more attention has been paid to studying low-dose, even ultra-low-dose x-ray CT. However, reducing CT radiation exposure will increase noise level in the sinogram, thereby degrading the quality of reconstructed CT images as well as causing more streak artifacts near the apices of the lung. Thus, how to reduce the noise levels and streak artifacts in the low-dose CT images is becoming a meaningful topic. Since multi-slice helical CT has replaced conventional stop-and-shoot CT in many clinical applications, this research mainly focused on the noise reduction issue in multi-slice helical CT. The experiment data were provided by Siemens SOMATOM Sensation 16-Slice helical CT. It included both conventional CT data acquired under 120 kvp voltage and 119 mA current and ultra-low-dose CT data acquired under 120 kvp and 10 mA protocols. All other settings are the same as that of conventional CT. In this paper, a nonparametric smoothing method with thin plate smoothing splines and the roughness penalty was proposed to restore the ultra-low-dose CT raw data. Each projection frame was firstly divided into blocks, and then the 2D data in each block was fitted to a thin-plate smoothing splines' surface via minimizing a roughness-penalized least squares objective function. By doing so, the noise in each ultra-low-dose CT projection was reduced by leveraging the information contained not only within each individual projection profile, but also among nearby profiles. Finally the restored ultra-low-dose projection data were fed into standard filtered back projection (FBP) algorithm to reconstruct CT images. The rebuilt results as well as the comparison between proposed approach and traditional method were given in the results and

  8. Pearls and pitfalls in the diagnosis of ureterolithiasis with unenhanced helical CT.

    PubMed

    Dalrymple, N C; Casford, B; Raiken, D P; Elsass, K D; Pagan, R A

    2000-01-01

    Several signs to assist interpretation of unenhanced helical computed tomographic (CT) scans obtained for suspected ureterolithiasis have been described. Because signs such as perinephric stranding are not always readily apparent, a methodical approach to interpretation of CT studies is important in determining the presence or absence of ureterolithiasis. Evaluation of the poles of the kidneys is helpful in detecting subtle stranding of the perinephric fat. Inspection of the intrarenal collecting system within the poles of the kidneys is helpful in identifying subtle collecting system dilatation and can help prevent mistaking an extrarenal pelvis for hydronephrosis. Careful inspection of the ureter throughout its course is the most reliable method of distinguishing between ureteral stones and phleboliths. However, when the ureter cannot be followed antegrade, the pelvic portion can often be identified in a retrograde fashion. When secondary signs of obstruction are present but no stone is present, differential diagnostic considerations include a recently passed stone, pyelonephritis, urinary tract obstruction unrelated to stone disease, and protease inhibitor deposition disease.

  9. A motion-compensated scheme for helical cone-beam reconstruction in cardiac CT angiography

    SciTech Connect

    Stevendaal, U. van; Berg, J. von; Lorenz, C.; Grass, M.

    2008-07-15

    Since coronary heart disease is one of the main causes of death all over the world, cardiac computed tomography (CT) imaging is an application of very high interest in order to verify indications timely. Due to the cardiac motion, electrocardiogram (ECG) gating has to be implemented into the reconstruction of the measured projection data. However, the temporal and spatial resolution is limited due to the mechanical movement of the gantry and due to the fact that a finite angular span of projections has to be acquired for the reconstruction of each voxel. In this article, a motion-compensated reconstruction method for cardiac CT is described, which can be used to increase the signal-to-noise ratio or to suppress motion blurring. Alternatively, it can be translated into an improvement of the temporal and spatial resolution. It can be applied to the entire heart in common and to high contrast objects moving with the heart in particular, such as calcified plaques or devices like stents. The method is based on three subsequent steps: As a first step, the projection data acquired in low pitch helical acquisition mode together with the ECG are reconstructed at multiple phase points. As a second step, the motion-vector field is calculated from the reconstructed images in relation to the image in a reference phase. Finally, a motion-compensated reconstruction is carried out for the reference phase using those projections, which cover the cardiac phases for which the motion-vector field has been determined.

  10. Myocardial ischemia detection with single-phase CT perfusion in symptomatic patients using high-pitch helical image acquisition technique.

    PubMed

    Bischoff, Bernhard; Deseive, Simon; Rampp, Martin; Todica, Andrei; Wermke, Marc; Martinoff, Stefan; Massberg, Steffen; Reiser, Maximilian F; Becker, Hans-Christoph; Hausleiter, Jörg

    2017-04-01

    Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p < 0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone.

  11. Improvement of spatial resolution in the longitudinal direction for isotropic imaging in helical CT

    NASA Astrophysics Data System (ADS)

    Tsukagoshi, Shinsuke; Ota, Takamasa; Fujii, Misako; Kazama, Masahiro; Okumura, Miwa; Johkoh, Takeshi

    2007-02-01

    Experiments were conducted to confirm the isotropic spatial resolution of multislice CT with a 0.5 mm slice thickness. Isotropic spatial resolution means that the spatial resolution in the transaxial plane (X-Y plane) and that in the longitudinal direction (Z direction) are equivalent. To obtain point spread function (PSF) values in the X-Y-Z directions, three-dimensional voxel data were obtained by helical scanning of a bead phantom. The modulation transfer function (MTF) values were then obtained by three-dimensional Fourier transform of the PSF. Evaluation of the spatial resolution in the X-Y-Z directions by the MTF values showed that the spatial resolution in the Z direction does not depend on the reconstruction kernel used. It was also found that the spatial resolution in the Z direction, as compared with that in the X-Y plane, is superior with the standard kernel for the abdomen and is inferior with the high-definition kernel for the ears/bones. By performing sharpening filter processing in the Z direction with a high-definition kernel, comparable spatial resolution could be obtained in the X-Y-Z directions. It was confirmed that adjusting the spatial resolution in the Z direction with the reconstruction kernel used is an effective method for isotropic imaging.

  12. Effect of CT contrast on volumetric arc therapy planning (RapidArc and helical tomotherapy) for head and neck cancer.

    PubMed

    Liu, Alan J; Vora, Nayana; Suh, Steve; Liu, An; Schultheiss, Timothy E; Wong, Jeffrey Y C

    2015-01-01

    The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V45Gy, V30Gy, and V20Gy organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  13. Effect of CT contrast on volumetric arc therapy planning (RapidArc and helical tomotherapy) for head and neck cancer

    SciTech Connect

    Liu, Alan J.; Vora, Nayana; Suh, Steve; Liu, An; Schultheiss, Timothy E.; Wong, Jeffrey Y.C.

    2015-04-01

    The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V{sub 45} {sub Gy}, V{sub 30} {sub Gy}, and V{sub 20} {sub Gy} organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way.

  14. 4D-Imaging of the Lung: Reproducibility of Lesion Size and Displacement on Helical CT, MRI, and Cone Beam CT in a Ventilated Ex Vivo System

    SciTech Connect

    Biederer, Juergen Dinkel, Julien; Remmert, Gregor; Jetter, Siri; Nill, Simeon; Moser, Torsten; Bendl, Rolf; Thierfelder, Carsten; Fabel, Michael; Oelfke, Uwe; Bock, Michael; Plathow, Christian; Bolte, Hendrik; Welzel, Thomas; Hoffmann, Beata; Hartmann, Guenter; Schlegel, Wolfgang; Debus, Juergen; Heller, Martin

    2009-03-01

    Purpose: Four-dimensional (4D) imaging is a key to motion-adapted radiotherapy of lung tumors. We evaluated in a ventilated ex vivo system how size and displacement of artificial pulmonary nodules are reproduced with helical 4D-CT, 4D-MRI, and linac-integrated cone beam CT (CBCT). Methods and Materials: Four porcine lungs with 18 agarose nodules (mean diameters 1.3-1.9 cm), were ventilated inside a chest phantom at 8/min and subject to 4D-CT (collimation 24 x 1.2 mm, pitch 0.1, slice/increment 24x10{sup 2}/1.5/0.8 mm, pitch 0.1, temporal resolution 0.5 s), 4D-MRI (echo-shared dynamic three-dimensional-flash; repetition/echo time 2.13/0.72 ms, voxel size 2.7 x 2.7 x 4.0 mm, temporal resolution 1.4 s) and linac-integrated 4D-CBCT (720 projections, 3-min rotation, temporal resolution {approx}1 s). Static CT without respiration served as control. Three observers recorded lesion size (RECIST-diameters x/y/z) and axial displacement. Interobserver- and interphase-variation coefficients (IO/IP VC) of measurements indicated reproducibility. Results: Mean x/y/z lesion diameters in cm were equal on static and dynamic CT (1.88/1.87; 1.30/1.39; 1.71/1.73; p > 0.05), but appeared larger on MRI and CBCT (2.06/1.95 [p < 0.05 vs. CT]; 1.47/1.28 [MRI vs. CT/CBCT p < 0.05]; 1.86/1.83 [CT vs. CBCT p < 0.05]). Interobserver-VC for lesion sizes were 2.54-4.47% (CT), 2.29-4.48% (4D-CT); 5.44-6.22% (MRI) and 4.86-6.97% (CBCT). Interphase-VC for lesion sizes ranged from 2.28% (4D-CT) to 10.0% (CBCT). Mean displacement in cm decreased from static CT (1.65) to 4D-CT (1.40), CBCT (1.23) and MRI (1.16). Conclusions: Lesion sizes are exactly reproduced with 4D-CT but overestimated on 4D-MRI and CBCT with a larger variability due to limited temporal and spatial resolution. All 4D-modalities underestimate lesion displacement.

  15. 4D-Imaging of the lung: reproducibility of lesion size and displacement on helical CT, MRI, and cone beam CT in a ventilated ex vivo system.

    PubMed

    Biederer, Juergen; Dinkel, Julien; Remmert, Gregor; Jetter, Siri; Nill, Simeon; Moser, Torsten; Bendl, Rolf; Thierfelder, Carsten; Fabel, Michael; Oelfke, Uwe; Bock, Michael; Plathow, Christian; Bolte, Hendrik; Welzel, Thomas; Hoffmann, Beata; Hartmann, Günter; Schlegel, Wolfgang; Debus, Jürgen; Heller, Martin; Kauczor, Hans-Ulrich

    2009-03-01

    Four-dimensional (4D) imaging is a key to motion-adapted radiotherapy of lung tumors. We evaluated in a ventilated ex vivo system how size and displacement of artificial pulmonary nodules are reproduced with helical 4D-CT, 4D-MRI, and linac-integrated cone beam CT (CBCT). Four porcine lungs with 18 agarose nodules (mean diameters 1.3-1.9 cm), were ventilated inside a chest phantom at 8/min and subject to 4D-CT (collimation 24 x 1.2 mm, pitch 0.1, slice/increment 24 x 10(2)/1.5/0.8 mm, pitch 0.1, temporal resolution 0.5 s), 4D-MRI (echo-shared dynamic three-dimensional-flash; repetition/echo time 2.13/0.72 ms, voxel size 2.7 x 2.7 x 4.0 mm, temporal resolution 1.4 s) and linac-integrated 4D-CBCT (720 projections, 3-min rotation, temporal resolution approximately 1 s). Static CT without respiration served as control. Three observers recorded lesion size (RECIST-diameters x/y/z) and axial displacement. Interobserver- and interphase-variation coefficients (IO/IP VC) of measurements indicated reproducibility. Mean x/y/z lesion diameters in cm were equal on static and dynamic CT (1.88/1.87; 1.30/1.39; 1.71/1.73; p > 0.05), but appeared larger on MRI and CBCT (2.06/1.95 [p < 0.05 vs. CT]; 1.47/1.28 [MRI vs. CT/CBCT p < 0.05]; 1.86/1.83 [CT vs. CBCT p < 0.05]). Interobserver-VC for lesion sizes were 2.54-4.47% (CT), 2.29-4.48% (4D-CT); 5.44-6.22% (MRI) and 4.86-6.97% (CBCT). Interphase-VC for lesion sizes ranged from 2.28% (4D-CT) to 10.0% (CBCT). Mean displacement in cm decreased from static CT (1.65) to 4D-CT (1.40), CBCT (1.23) and MRI (1.16). Lesion sizes are exactly reproduced with 4D-CT but overestimated on 4D-MRI and CBCT with a larger variability due to limited temporal and spatial resolution. All 4D-modalities underestimate lesion displacement.

  16. Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

    NASA Astrophysics Data System (ADS)

    Dou, Hsiang-Tai

    The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan

  17. Technical Note: FreeCT_wFBP: A robust, efficient, open-source implementation of weighted filtered backprojection for helical, fan-beam CT

    PubMed Central

    Hoffman, John; Young, Stefano; Noo, Frédéric

    2016-01-01

    Purpose: With growing interest in quantitative imaging, radiomics, and CAD using CT imaging, the need to explore the impacts of acquisition and reconstruction parameters has grown. This usually requires extensive access to the scanner on which the data were acquired and its workflow is not designed for large-scale reconstruction projects. Therefore, the authors have developed a freely available, open-source software package implementing a common reconstruction method, weighted filtered backprojection (wFBP), for helical fan-beam CT applications. Methods: FreeCT_wFBP is a low-dependency, GPU-based reconstruction program utilizing c for the host code and Nvidia CUDA C for GPU code. The software is capable of reconstructing helical scans acquired with arbitrary pitch-values, and sampling techniques such as flying focal spots and a quarter-detector offset. In this work, the software has been described and evaluated for reconstruction speed, image quality, and accuracy. Speed was evaluated based on acquisitions of the ACR CT accreditation phantom under four different flying focal spot configurations. Image quality was assessed using the same phantom by evaluating CT number accuracy, uniformity, and contrast to noise ratio (CNR). Finally, reconstructed mass-attenuation coefficient accuracy was evaluated using a simulated scan of a FORBILD thorax phantom and comparing reconstructed values to the known phantom values. Results: The average reconstruction time evaluated under all flying focal spot configurations was found to be 17.4 ± 1.0 s for a 512 row × 512 column × 32 slice volume. Reconstructions of the ACR phantom were found to meet all CT Accreditation Program criteria including CT number, CNR, and uniformity tests. Finally, reconstructed mass-attenuation coefficient values of water within the FORBILD thorax phantom agreed with original phantom values to within 0.0001 mm2/g (0.01%). Conclusions: FreeCT_wFBP is a fast, highly configurable reconstruction package for

  18. Technical Note: FreeCT_wFBP: A robust, efficient, open-source implementation of weighted filtered backprojection for helical, fan-beam CT.

    PubMed

    Hoffman, John; Young, Stefano; Noo, Frédéric; McNitt-Gray, Michael

    2016-03-01

    With growing interest in quantitative imaging, radiomics, and CAD using CT imaging, the need to explore the impacts of acquisition and reconstruction parameters has grown. This usually requires extensive access to the scanner on which the data were acquired and its workflow is not designed for large-scale reconstruction projects. Therefore, the authors have developed a freely available, open-source software package implementing a common reconstruction method, weighted filtered backprojection (wFBP), for helical fan-beam CT applications. FreeCT_wFBP is a low-dependency, GPU-based reconstruction program utilizing c for the host code and Nvidia CUDA C for GPU code. The software is capable of reconstructing helical scans acquired with arbitrary pitch-values, and sampling techniques such as flying focal spots and a quarter-detector offset. In this work, the software has been described and evaluated for reconstruction speed, image quality, and accuracy. Speed was evaluated based on acquisitions of the ACR CT accreditation phantom under four different flying focal spot configurations. Image quality was assessed using the same phantom by evaluating CT number accuracy, uniformity, and contrast to noise ratio (CNR). Finally, reconstructed mass-attenuation coefficient accuracy was evaluated using a simulated scan of a FORBILD thorax phantom and comparing reconstructed values to the known phantom values. The average reconstruction time evaluated under all flying focal spot configurations was found to be 17.4 ± 1.0 s for a 512 row × 512 column × 32 slice volume. Reconstructions of the ACR phantom were found to meet all CT Accreditation Program criteria including CT number, CNR, and uniformity tests. Finally, reconstructed mass-attenuation coefficient values of water within the FORBILD thorax phantom agreed with original phantom values to within 0.0001 mm(2)/g (0.01%). FreeCT_wFBP is a fast, highly configurable reconstruction package for third-generation CT available under

  19. Extending Three-Dimensional Weighted Cone Beam Filtered Backprojection (CB-FBP) Algorithm for Image Reconstruction in Volumetric CT at Low Helical Pitches

    PubMed Central

    Hsieh, Jiang; Nilsen, Roy A.; McOlash, Scott M.

    2006-01-01

    A three-dimensional (3D) weighted helical cone beam filtered backprojection (CB-FBP) algorithm (namely, original 3D weighted helical CB-FBP algorithm) has already been proposed to reconstruct images from the projection data acquired along a helical trajectory in angular ranges up to [0, 2 π]. However, an overscan is usually employed in the clinic to reconstruct tomographic images with superior noise characteristics at the most challenging anatomic structures, such as head and spine, extremity imaging, and CT angiography as well. To obtain the most achievable noise characteristics or dose efficiency in a helical overscan, we extended the 3D weighted helical CB-FBP algorithm to handle helical pitches that are smaller than 1: 1 (namely extended 3D weighted helical CB-FBP algorithm). By decomposing a helical over scan with an angular range of [0, 2π + Δβ] into a union of full scans corresponding to an angular range of [0, 2π], the extended 3D weighted function is a summation of all 3D weighting functions corresponding to each full scan. An experimental evaluation shows that the extended 3D weighted helical CB-FBP algorithm can improve noise characteristics or dose efficiency of the 3D weighted helical CB-FBP algorithm at a helical pitch smaller than 1: 1, while its reconstruction accuracy and computational efficiency are maintained. It is believed that, such an efficient CB reconstruction algorithm that can provide superior noise characteristics or dose efficiency at low helical pitches may find its extensive applications in CT medical imaging. PMID:23165031

  20. Prospectively ECG gated CT pulmonary angiography versus helical ungated CT pulmonary angiography: impact on cardiac related motion artifacts and patient radiation dose.

    PubMed

    Shuman, William P; Leipsic, Jonathon A; Busey, Janet M; Green, Douglas E; Pipavath, Sudhakar N; Hague, Cameron J; Koprowicz, Kent M

    2012-09-01

    To compare prospectively ECG gated CT pulmonary angiography (CTPA) with routine helical ungated CTPA for cardiac related motion artifacts and patient radiation dose. Twenty patients with signs and symptoms suspicious for pulmonary embolism and who had a heart rate below 85 were scanned with prospectively ECG gated CTPA. These gated exams were matched for several clinical parameters to exams from twenty similar clinical patients scanned with routine ungated helical CTPA. Three blinded independent reviewers subjectively evaluated all exams for overall pulmonary artery enhancement and for several cardiac motion related artifacts, including vessel blurring, intravascular shading, and double line. Reviewers also measured pulmonary artery intravascular density and image noise. Patient radiation dose for each technique was compared. Fourteen clinical prospectively ECG gated CTPA exams from a second institution were evaluated for the same parameters. Prospectively ECG gated CTPA resulted in significantly decreased motion-related image artifact scores in lung segments adjacent to the heart compared to ungated CTPA. Measured image noise was not significantly different between the two types of CTPA exams. Effective dose was 28% less for prospectively ECG gated CTPA (4.9 mSv versus 6.8 mSv, p=0.02). Similar results were found in the prospectively ECG gated exams from the second institution. Compared to routine helical ungated CTPA, prospectively ECG gated CTPA may result in less cardiac related motion artifact in lung segments adjacent to the heart and significantly less patient radiation dose. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  1. Diagnostic performance of reformatted isotropic thin-section helical CT images in the detection of superior semicircular canal dehiscence.

    PubMed

    Sparacia, Gianvincenzo; Iaia, Alberto

    2017-06-01

    Purpose The purpose of this article is to assess the diagnostic performance of computed tomography (CT) reformatted images for detection of superior semicircular canal (SSC) dehiscence. Material and methods Forty-two patients, with sound- and/or pressure-induced vestibular symptoms, and 42 control participants underwent helical CT examination with a highly collimated beam (0.5 mm). Reformatted images of the vestibular labyrinth were obtained in the standard axial and coronal planes (group A images), and in a plane parallel and perpendicular to the SSC (group B images). Diagnostic performance obtained by evaluating the group A images alone and the group B images alone was analyzed by using the area under the receiver operating characteristic curve (AUC). Results The diagnostic performance of group A images was AUC = 0.929 with an overall accuracy of 92.9%. The diagnostic performance of group B images was AUC = 0.988 with an overall accuracy of 98.8%. The evaluation of group B images alone showed an improved diagnostic performance over the group A images alone. Conclusion Thin-section 0.5-mm collimation CT with reformatted images oriented in the plane parallel and perpendicular to the SSC improves diagnostic accuracy in assessing for SSC dehiscence in comparison to CT images with reconstructions limited to traditional axial and coronal planes.

  2. [The effect of the severity of congenital pectus excavatum on the cardiac morphology in children: evaluation with multislice helical CT].

    PubMed

    Lu, Tao; Deng, Kaihong

    2013-12-01

    This paper is aimed to evaluate the CT manifestation of congenital pectus excavatum and its effect on the cardiac morphology. CT features of 34 children with pectus excavatum were retrospectively reviewed. The Haller index (HI), CT depression index (CTDI), cardiac rotation angle (CRA), pulmonary vein angle (PVA), cardiac compression index (CCI) and cardiac asymmetry index (CAI) were measured from the images on the PACS system. The relationships among these indexes were evaluated. The HI was 4.12 +/- 1.48, the CTDI was 2.39+/- 0.70, CRA was (53.52 +/- 7.68) degrees, PVA was (66.51 +/- 11.02) degrees, CCI was 2.43 +/- 0.95, and CAI was 1.55 +/- 0.56. There was statistical significance of CCI and CAI between children with severe or slight pectus excavatum. The HI and CTDI were positively related with CCI and CAI respectively, whereas there was no statistical significance of CRA and PVA between children with severe or slight pectus excavatum. There was no statistical significance of HI, CTDI, CRA, PVA, CCI and CAI among different age groups. The morphological change of the heart compressed in children with pectus excavatum can be accurately evaluated by multislice helical CT.

  3. Using Helical CT to Predict Stone Fragility in Shock Wave Lithotripsy (SWL)

    NASA Astrophysics Data System (ADS)

    Williams, James C.; Zarse, Chad A.; Jackson, Molly E.; Lingeman, James E.; McAteer, James A.

    2007-04-01

    Great variability exists in the response of urinary stones to SWL, and this is true even for stones composed of the same mineral. Efforts have been made to predict stone fragility to shock waves using computed tomography (CT) patient images, but most work to date has focused on the use of stone CT number (i.e., Hounsfield units). This is an easy number to measure on a patient stone, but its value depends on a number of factors, including the relationship of the size of the stone to me resolution (i.e., the slicewidth) of the CT scan. Studies that have shown a relationship between stone CT number and failure in SWL are reviewed, and all are shown to suffer from error due to stone size, which was not accounted for in the use of Hounsfield unit values. Preliminary data are then presented for a study of calcium oxalate monohydrate (COM) stones, in which stone structure—rather than simple CT number values—is shown to correlate with fragility to shock waves. COM stones that were observed to have structure by micro CT (e.g., voids, apatite regions, unusual shapes) broke to completion in about half the number of shock waves required for COM stones that were observed to be homogeneous in structure by CT. This result suggests another direction for the use of CT in predicting success of SWL: the use of CT to view stone structure, rather than simply measuring stone CT number. Viewing stone structure by CT requires the use of different viewing windows than those typically used for examining patient scans, but much research to date indicates that stone structure can be observed in the clinical setting. Future clinical studies will need to be done to verify the relationship between stone structure observed by CT and stone fragility in SWL.

  4. Using Helical CT to Predict Stone Fragility in Shock Wave Lithotripsy (SWL)

    SciTech Connect

    Williams, James C. Jr.; Zarse, Chad A.; Jackson, Molly E.; McAteer, James A.; Lingeman, James E.

    2007-04-05

    Great variability exists in the response of urinary stones to SWL, and this is true even for stones composed of the same mineral. Efforts have been made to predict stone fragility to shock waves using computed tomography (CT) patient images, but most work to date has focused on the use of stone CT number (i.e., Hounsfield units). This is an easy number to measure on a patient stone, but its value depends on a number of factors, including the relationship of the size of the stone to me resolution (i.e., the slicewidth) of the CT scan. Studies that have shown a relationship between stone CT number and failure in SWL are reviewed, and all are shown to suffer from error due to stone size, which was not accounted for in the use of Hounsfield unit values. Preliminary data are then presented for a study of calcium oxalate monohydrate (COM) stones, in which stone structure-rather than simple CT number values-is shown to correlate with fragility to shock waves. COM stones that were observed to have structure by micro CT (e.g., voids, apatite regions, unusual shapes) broke to completion in about half the number of shock waves required for COM stones that were observed to be homogeneous in structure by CT. This result suggests another direction for the use of CT in predicting success of SWL: the use of CT to view stone structure, rather than simply measuring stone CT number. Viewing stone structure by CT requires the use of different viewing windows than those typically used for examining patient scans, but much research to date indicates that stone structure can be observed in the clinical setting. Future clinical studies will need to be done to verify the relationship between stone structure observed by CT and stone fragility in SWL.

  5. Evaluation of suspected appendicitis in children using limited helical CT and colonic contrast material.

    PubMed

    Mullins, M E; Kircher, M F; Ryan, D P; Doody, D; Mullins, T C; Rhea, J T; Novelline, R A

    2001-01-01

    Colonic contrast material evaluation of suspected appendicitis in pediatric patients is technically more challenging than in adults because less intraabdominal fat is present. To determine the accuracy and feasibility of focused CT for pediatric patients, we carried out this retrospective investigation. Between November 1995 and July 1999, 199 pediatric patients (1-18 years old; mean age, 12 years) were examined with focused CT in the emergency division for suspected appendicitis. The findings on CT were compared with the findings at surgery, pathology, and clinical follow-up. There were 64 true-positive CT scans, two false-negative, 128 true-negative, one false-positive, and four indeterminate. Seventy-four patients underwent appendectomy, with a negative appendectomy rate of 9%. One hundred twenty-five patients without appendicitis were treated nonoperatively. The true-positive rate was 32%, true-negative rate was 64%, sensitivity was 97%, specificity was 99%, positive predictive value was 98%, negative predictive value was 98%, and overall accuracy was 96%. Pediatric patients tolerated the procedure well. Colonic contrast material saved time and provided improved identification of the cecum and appendix. In 62 patients without appendicitis, focused CT provided alternative diagnoses. Focused CT appears to be nearly as accurate in pediatric patients as in adults. Focused CT provided alternative diagnoses in 48% of the patients for whom CT findings were negative for appendicitis.

  6. Is there an ideal set of prospective scan acquisition phases for fast-helical based 4D-CT?

    NASA Astrophysics Data System (ADS)

    Thomas, D. H.; Ruan, D.; Williams, P.; Lamb, J.; White, B. M.; Dou, T.; O'Connell, D.; Lee, P.; Low, D. A.

    2016-12-01

    The article aims to determine if a prospective acquisition algorithm can be used to find the ideal set of free-breathing phases for fast-helical model-based 4D-CT. A retrospective five-patient dataset that consisted of 25 repeated free breathing CT scans per patient was used. The sum of the square root amplitude difference between all the breathing phases was defined as an objective function to determine the optimality of sets of breathing phases. The objective function was intended to determine if a specific set of breathing phases would yield a motion model that could accurately predict the motion in all 25 CT scans. Voxel specific motion models were calculated using all combinations of N scans from 25 breathing trajectories, (3  ⩽  N  ⩽  25), and the minimum number of scans required to absolutely characterize the motion model was analyzed. This analysis suggests that the number of scans could potentially be reduced to as few as five scans. When the objective function was large, the resulting motion model provided an excellent approximation to the motion model created using all 25 scans.

  7. A three-dimensional statistical approach to improved image quality for multislice helical CT

    SciTech Connect

    Thibault, Jean-Baptiste; Sauer, Ken D.; Bouman, Charles A.; Hsieh, Jiang

    2007-11-15

    Multislice helical computed tomography scanning offers the advantages of faster acquisition and wide organ coverage for routine clinical diagnostic purposes. However, image reconstruction is faced with the challenges of three-dimensional cone-beam geometry, data completeness issues, and low dosage. Of all available reconstruction methods, statistical iterative reconstruction (IR) techniques appear particularly promising since they provide the flexibility of accurate physical noise modeling and geometric system description. In this paper, we present the application of Bayesian iterative algorithms to real 3D multislice helical data to demonstrate significant image quality improvement over conventional techniques. We also introduce a novel prior distribution designed to provide flexibility in its parameters to fine-tune image quality. Specifically, enhanced image resolution and lower noise have been achieved, concurrently with the reduction of helical cone-beam artifacts, as demonstrated by phantom studies. Clinical results also illustrate the capabilities of the algorithm on real patient data. Although computational load remains a significant challenge for practical development, superior image quality combined with advancements in computing technology make IR techniques a legitimate candidate for future clinical applications.

  8. Diagnosis and staging of pancreatic cancer: comparison of mangafodipir trisodium-enhanced MR imaging and contrast-enhanced helical hydro-CT.

    PubMed

    Schima, Wolfgang; Függer, Reinhold; Schober, Ewald; Oettl, Claudia; Wamser, Peter; Grabenwöger, Florian; Ryan, J Mark; Novacek, Gottfried

    2002-09-01

    The purpose of this study was to compare mangafodipir trisodium-enhanced MR imaging performed with a phased array coil and contrast-enhanced single-detector helical CT for accuracy in the detection and local staging of pancreatic adenocarcinoma and in the differentiation between cancer and focal pancreatitis. Forty-two patients with suspected pancreatic masses underwent contrast-enhanced helical CT and mangafodipir trisodium-enhanced MR imaging at 1.5 T. The images were assessed for the presence or absence of tumors; characterization of masses; and presence of vascular invasion, lymph node metastases, or liver metastases. Imaging findings were correlated with findings at laparotomy, laparoscopy, biopsy, or follow-up. Focal masses were present in 36 patients (cancer, n = 26; focal pancreatitis, n = 7; other, n = 3). The sensitivity for lesion detection of MR imaging was 100% and of CT, 94%. Two small malignant lesions were missed on CT. For the diagnosis of tumor nonresectability, the sensitivity of MR imaging and CT was 90% and 80%, respectively. Liver metastases were missed on MR imaging in one of the eight patients and on CT in four. For differentiation between adenocarcinoma and nonadenocarcinoma, the sensitivity of MR imaging was 100% (positive predictive value, 90%; negative predictive value, 100%), and the sensitivity of CT was 92% (positive predictive value, 80%; negative predictive value, 67%). Receiver operating characteristic analysis revealed that the mean area under the curve for MR imaging was 0.920 and for CT, 0.832 (not significant). Mangafodipir trisodium-enhanced MR imaging is as accurate as contrast-enhanced helical CT for the detection and staging of pancreatic cancer but offers improved detection of small pancreatic metastases and of liver metastases compared with CT.

  9. Evaluation of exposure dose reduction in multislice CT coronary angiography (MS-CTA) with prospective ECG-gated helical scan

    NASA Astrophysics Data System (ADS)

    Ota, Takamasa; Tsuyuki, Masaharu; Okumura, Miwa; Sano, Tomonari; Kondo, Takeshi; Takase, Shinichi

    2008-03-01

    A novel low-dose ECG-gated helical scan method to investigate coronary artery diseases was developed. This method uses a high pitch for scanning (based on the patient's heart rate) and X-rays are generated only during the optimal cardiac phases. The dose reduction was obtained using a two-level approach: 1) To use a 64-slice CT scanner (Aquilion, Toshiba, Otawara, Tochigi, Japan) with a scan speed of 0.35 s/rot. to helically scan the heart at a high pitch based on the patient's heart rate. By changing the pitch from the conventional 0.175 to 0.271 for a heart rate of 60 bpm, the exposure dose was reduced to 65%. 2) To employ tube current gating that predicts the timing of optimal cardiac phases from the previous cardiac cycle and generates X-rays only during the required cardiac phases. The combination of high speed scanning with a high pitch and appropriate X-ray generation only in the cardiac phases from 60% to 90% allows the exposure dose to be reduced to 5.6 mSv for patients with a heart rate lower than 65 bpm. This is a dose reduction of approximately 70% compared to the conventional scanning method recommended by the manufacturer when segmental reconstruction is considered. This low-dose protocol seamlessly allows for wide scan ranges (e.g., aortic dissection) with the benefits of ECG-gated helical scanning: smooth continuity for longitudinal direction and utilization of data from all cardiac cycles.

  10. Patterns of CT lung injury and toxicity after stereotactic radiotherapy delivered with helical tomotherapy in early stage medically inoperable NSCLC

    PubMed Central

    Agolli, L; Portalone, L; Migliorino, M R; Lopergolo, M G; Monaco, A; Dognini, J; Pressello, M C; Bracci, S; Donato, V

    2015-01-01

    Objective: To evaluate toxicity and patterns of radiologic lung injury on CT images after hypofractionated image-guided stereotactic body radiotherapy (SBRT) delivered with helical tomotherapy (HT) in medically early stage inoperable non-small-cell lung cancer (NSCLC). Methods: 28 elderly patients (31 lesions) with compromised pulmonary reserve were deemed inoperable and enrolled to undergo SBRT. Patterns of lung injury based on CT appearance were assessed at baseline and during follow up. Acute (6 months or less) and late (more than 6 months) events were classified as radiation pneumonitis and radiation fibrosis (RF), respectively. Results: After a median follow-up of 12 months (range, 4–20 months), 31 and 25 lesions were examined for acute and late injuries, respectively. Among the former group, 25 (80.6%) patients showed no radiological changes. The CT appearance of RF revealed modified conventional, mass-like and scar-like patterns in three, four and three lesions, respectively. No evidence of late lung injury was demonstrated in 15 lesions. Five patients developed clinical pneumonitis (four patients, grade 2 and one patient, grade 3, respectively), and none of whom had CT findings at 3 months post-treatment. No instance of symptomatic RF was detected. The tumour response rate was 84% (complete response + partial response). Local control was 83% at 1 year. Conclusion: Our findings show that HT-SBRT can be considered an effective treatment with a mild toxicity profile in medically inoperable patients with early stage NSCLC. No specific pattern of lung injury was demonstrated. Advances in knowledge: Our study is among the few showing that HT-SBRT represents a safe and effective option in patients with early stage medically inoperable NSCLC, and that it is not associated with a specific pattern of lung injury. PMID:25645106

  11. Optimized reconstruction algorithm for helical CT with fractional pitch between 1PI and 3PI.

    PubMed

    Katsevich, Alexander; Zamyatin, Alexander A; Silver, Michael D

    2009-07-01

    We propose an approximate approach to use redundant data outside the 1PI window within the exact Katsevich reconstruction framework. The proposed algorithm allows a flexible selection of the helical pitch, which is useful for clinical applications. Our idea is an extension of the one proposed by KOhler, Bontus, and Koken (2006). It is based on optimizing the contribution weights of convolution families used in exact Katsevich 3PI algorithms, so that the total weight of each Radon plane is as close to 1 as possible. Optimization is based on solving a least squares problem subject to linear constrains. Numerical evaluation shows good noise and artifact reduction properties of the proposed algorithm.

  12. SU-E-I-93: Improved Imaging Quality for Multislice Helical CT Via Sparsity Regularized Iterative Image Reconstruction Method Based On Tensor Framelet

    SciTech Connect

    Nam, H; Guo, M; Lee, K; Li, R; Xing, L; Gao, H

    2014-06-01

    Purpose: Inspired by compressive sensing, sparsity regularized iterative reconstruction method has been extensively studied. However, its utility pertinent to multislice helical 4D CT for radiotherapy with respect to imaging quality, dose, and time has not been thoroughly addressed. As the beginning of such an investigation, this work carries out the initial comparison of reconstructed imaging quality between sparsity regularized iterative method and analytic method through static phantom studies using a state-of-art 128-channel multi-slice Siemens helical CT scanner. Methods: In our iterative method, tensor framelet (TF) is chosen as the regularization method for its superior performance from total variation regularization in terms of reduced piecewise-constant artifacts and improved imaging quality that has been demonstrated in our prior work. On the other hand, X-ray transforms and its adjoints are computed on-the-fly through GPU implementation using our previous developed fast parallel algorithms with O(1) complexity per computing thread. For comparison, both FDK (approximate analytic method) and Katsevich algorithm (exact analytic method) are used for multislice helical CT image reconstruction. Results: The phantom experimental data with different imaging doses were acquired using a state-of-art 128-channel multi-slice Siemens helical CT scanner. The reconstructed image quality was compared between TF-based iterative method, FDK and Katsevich algorithm with the quantitative analysis for characterizing signal-to-noise ratio, image contrast, and spatial resolution of high-contrast and low-contrast objects. Conclusion: The experimental results suggest that our tensor framelet regularized iterative reconstruction algorithm improves the helical CT imaging quality from FDK and Katsevich algorithm for static experimental phantom studies that have been performed.

  13. Helical CT Angiography of Abdominal Aortic Aneurysms Treated with Suprarenal Stent Grafting: A Pictorial Essay

    SciTech Connect

    Sun Zhonghua

    2003-06-15

    The endovascular repair of abdominal aorticaneurysm (AAA) with stent grafts is rapidly becoming an important alternative to open repair. Suprarenal stent grafting, recently modified from conventional infrarenal stent grafting, is a technique for the purpose of treating patients with inappropriate aneurysm necks.Unlike open repair, the success of endoluminal repair cannot be ascertained by means of direct examination and thus relies on imaging results. The use of conventional angiography for arterial imaging has become less dominant, while helical computed tomography angiography(CTA) has become the imaging modality of choice for both preoperative assessment and postoperative followup after treatment with stent graft implants. There is an increasing likelihood that radiologists will become more and more involved in the procedure of aortic stent grafting and in giving the radiological report on these patients treated with stent grafts. It is necessary for radiologists to be familiar with the imaging findings, including common and uncommon appearances following aortic stent grafting. The purpose of this pictorial essay is to describe and present normal and abnormal imaging appearances following aortic stent grafting based on helical CTA.

  14. Fuzzy Clustering Applied to ROI Detection in Helical Thoracic CT Scans with a New Proposal and Variants

    PubMed Central

    Castro, Alfonso; Boveda, Carmen; Arcay, Bernardino; Sanjurjo, Pedro

    2016-01-01

    The detection of pulmonary nodules is one of the most studied problems in the field of medical image analysis due to the great difficulty in the early detection of such nodules and their social impact. The traditional approach involves the development of a multistage CAD system capable of informing the radiologist of the presence or absence of nodules. One stage in such systems is the detection of ROI (regions of interest) that may be nodules in order to reduce the space of the problem. This paper evaluates fuzzy clustering algorithms that employ different classification strategies to achieve this goal. After characterising these algorithms, the authors propose a new algorithm and different variations to improve the results obtained initially. Finally it is shown as the most recent developments in fuzzy clustering are able to detect regions that may be nodules in CT studies. The algorithms were evaluated using helical thoracic CT scans obtained from the database of the LIDC (Lung Image Database Consortium). PMID:27517049

  15. TH-C-18A-11: Investigating the Minimum Scan Parameters Required to Generate Free-Breathing Fast-Helical CT Scans Without Motion-Artifacts

    SciTech Connect

    Thomas, D; Neylon, J; Dou, T; Jani, S; Lamb, J; Low, D; Tan, J

    2014-06-15

    Purpose: A recently proposed 4D-CT protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artifacts, which arise when tissue motion is greater than scan speed. This work identifies the minimum scanner parameters required to successfully generate free-breathing fast-helical scans without doubling-artifacts. Methods: 10 patients were imaged under free breathing conditions 25 times in alternating directions with a 64-slice CT scanner using a low dose fast helical protocol. A high temporal resolution (0.1s) 4D-CT was generated using a patient specific motion model and patient breathing waveforms, and used as the input for a scanner simulation. Forward projections were calculated using helical cone-beam geometry (800 projections per rotation) and a GPU accelerated reconstruction algorithm was implemented. Various CT scanner detector widths and rotation times were simulated, and verified using a motion phantom. Doubling-artifacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices. Results: Increasing amounts of doubling-artifacts were observed with increasing rotation times > 0.2s for 16×1mm slice scan geometry. No significant increase in doubling artifacts was observed for 64×1mm slice scan geometry up to 1.0s rotation time although blurring artifacts were observed >0.6s. Using a 16×1mm slice scan geometry, a rotation time of less than 0.3s (53mm/s scan speed) would be required to produce images of similar quality to a 64×1mm slice scan geometry. Conclusion: The current generation of 16 slice CT scanners, which are present in most Radiation Oncology departments, are not capable of generating free-breathing sorting-artifact-free images in the majority of patients. The next generation of CT scanners should be capable of at least 53mm/s scan speed

  16. kVCT, MVCT, and hybrid CT image studies-Treatment planning and dose delivery equivalence on helical tomotherapy.

    PubMed

    Martin, Spencer; Yartsev, Slav

    2010-06-01

    To determine the equivalence of radiation therapy treatment planning and delivery for various imaging options on helical tomotherapy. Seven treatment plans using identical anatomy and planning parameters were created based on the following CT studies: Standard kilovoltage CT (kVCT); 2, 4, and 6 mm spacing megavoltage CT (MVCT); and 2, 4, and 6 mm hybrid MVCT/kVCT studies. In addition, two kVCT based plans were created to explore the effect of the choice of dose calculation grid for optimization. Calculated and measured dose distributions were compared via volumetric and dosimetric analysis at the planning stage, point dose measurements with ion chamber, along with EDR2 film data for gamma function analysis for distance to agreement of 3 mm and dose differences of 3%, 5%, and 7% using both the commercially available "cheese" phantom and the new QUASAR Verification (QVer) phantom. Plans created for each imaging option showed residual error increasing as image slice spacing increased and critical structure size decreased. With the exception of the low dose area in hybrid studies, point dose measurements were within the calculated/measured dose acceptance criteria of 5% on both the QVer and cheese phantoms. Gamma analysis for the original kVCT plan delivery showed an average of 98.5%±0.5% and 98.8%±0.3% of dose pixels passing kVCT study treatment and delivery quality assurance procedures, respectively. The QVer phantom allows for delivery quality assurance with simultaneous use of two films and more convenient gamma function assessment but shows some measurement discrepancy up to 10% compared to the cheese phantom. The kVCT, MVCT, and kVCT/MVCT hybrid studies showed considerable agreement at both planning and delivery stages. The choice of calculation grid is more important when dealing with smaller anatomical structures. © 2010 American Association of Physicists in Medicine.

  17. Distinguishing benign from malignant pulmonary nodules with helical chest CT in children with malignant solid tumors.

    PubMed

    McCarville, M Beth; Lederman, Henrique M; Santana, Victor M; Daw, Najat C; Shochat, Stephen J; Li, Chin-Shang; Kaufman, Robert A

    2006-05-01

    To retrospectively assess whether computed tomographic (CT) findings can indicate the benign or malignant nature of pulmonary nodules in pediatric patients with malignant solid primary tumors. With institutional review board approval, waived parental and patient consent, and HIPAA compliance, the authors determined the incidence of malignancy among 81 pulmonary nodules that were sampled at biopsy within 3 weeks after chest CT (January 1999 to September 2003) in 41 young patients with malignant solid tumors. Three radiologists independently and retrospectively reviewed these scans and the available previously obtained scans, classifying nodules as benign, malignant, or indeterminate on the basis of their number, unilateral versus bilateral distribution, size, margins (indistinct vs distinct), calcification, growth, and associated adenopathy. These classifications were compared with nodule histologic type, and interreviewer agreement was assessed. The median patient age was 14.8 years (mean, 13.7 years; range, 5-21 years). Twenty-four of the 41 patients (58%) had at least one biopsy-proved malignant nodule. Four (10%) patients had both benign and malignant nodules; 17 (42%) had only benign nodules. Reviewer 1 classified 65% (39 of 60) of nodules correctly; reviewer 2, 57% (37 of 65); and reviewer 3, 67% (43 of 64). Interreviewer agreement was slight to moderate (kappa /= .32). The frequency of benign nodules and the inconsistency of predictions based on CT features suggest the need for better predictors of pulmonary nodules being malignant or benign, so as to reduce unnecessary thoracotomy in pediatric patients with solid malignancy. . (c) RSNA, 2006.

  18. Optimization of multiplanar reformations from isotropic data sets acquired with 16-detector row helical CT scanner.

    PubMed

    Jaffe, Tracy A; Nelson, Rendon C; Johnson, G Allan; Lee, Ellie R; Yoshizumi, Terry T; Lowry, Carolyn R; Bullard, Anthony B; DeLong, David M; Paulson, Erik K

    2006-01-01

    Institutional review board approval and waiver of consent were obtained for the patient component of this retrospective HIPAA-compliant study. By using an anthropomorphic phantom and metal oxide semiconductor field effect transistor detectors, radiation dose was determined for one eight-detector row and two 16-detector row computed tomographic (CT) protocols. A custom phantom was scanned by using the three protocols to identify isotropy. Contrast-to-noise ratios (CNRs) were determined for the same protocols by using a third phantom. Seven patients had undergone isotropic 16-detector row CT of the abdomen and pelvis. Anonymized coronal reformations at various thicknesses were ranked qualitatively by three radiologists. Effective dose equivalents were similar for the eight- and 16-detector row protocols. When transverse and coronal reformations of data acquired in the custom phantom were compared, coronal reformations obtained with the 16-detector row and 0.625-mm section thickness protocol were found to be nearly identical to the transverse image for all sets of line pairs. CNRs were consistently highest on 5-mm-thick coronal reformations (CNR range, 1.2-3.3). For qualitative assessment, 2- and 3-mm-thick coronal reformations were consistently preferred.

  19. Noise reduction for low-dose helical CT by 3D penalized weighted least-squares sinogram smoothing

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Li, Tianfang; Lu, Hongbing; Liang, Zhengrong

    2006-03-01

    Helical computed tomography (HCT) has several advantages over conventional step-and-shoot CT for imaging a relatively large object, especially for dynamic studies. However, HCT may increase X-ray exposure significantly to the patient. This work aims to reduce the radiation by lowering the X-ray tube current (mA) and filtering the low-mA (or dose) sinogram noise. Based on the noise properties of HCT sinogram, a three-dimensional (3D) penalized weighted least-squares (PWLS) objective function was constructed and an optimal sinogram was estimated by minimizing the objective function. To consider the difference of signal correlation among different direction of the HCT sinogram, an anisotropic Markov random filed (MRF) Gibbs function was designed as the penalty. The minimization of the objection function was performed by iterative Gauss-Seidel updating strategy. The effectiveness of the 3D-PWLS sinogram smoothing for low-dose HCT was demonstrated by a 3D Shepp-Logan head phantom study. Comparison studies with our previously developed KL domain PWLS sinogram smoothing algorithm indicate that the KL+2D-PWLS algorithm shows better performance on in-plane noise-resolution trade-off while the 3D-PLWS shows better performance on z-axis noise-resolution trade-off. Receiver operating characteristic (ROC) studies by using channelized Hotelling observer (CHO) shows that 3D-PWLS and KL+2DPWLS algorithms have similar performance on detectability in low-contrast environment.

  20. Approximations of noise covariance in multi-slice helical CT scans: impact on lung nodule size estimation.

    PubMed

    Zeng, Rongping; Petrick, Nicholas; Gavrielides, Marios A; Myers, Kyle J

    2011-10-07

    Multi-slice computed tomography (MSCT) scanners have become popular volumetric imaging tools. Deterministic and random properties of the resulting CT scans have been studied in the literature. Due to the large number of voxels in the three-dimensional (3D) volumetric dataset, full characterization of the noise covariance in MSCT scans is difficult to tackle. However, as usage of such datasets for quantitative disease diagnosis grows, so does the importance of understanding the noise properties because of their effect on the accuracy of the clinical outcome. The goal of this work is to study noise covariance in the helical MSCT volumetric dataset. We explore possible approximations to the noise covariance matrix with reduced degrees of freedom, including voxel-based variance, one-dimensional (1D) correlation, two-dimensional (2D) in-plane correlation and the noise power spectrum (NPS). We further examine the effect of various noise covariance models on the accuracy of a prewhitening matched filter nodule size estimation strategy. Our simulation results suggest that the 1D longitudinal, 2D in-plane and NPS prewhitening approaches can improve the performance of nodule size estimation algorithms. When taking into account computational costs in determining noise characterizations, the NPS model may be the most efficient approximation to the MSCT noise covariance matrix.

  1. Helical CT scan with 2D and 3D reconstructions and virtual endoscopy versus conventional endoscopy in the assessment of airway disease in neonates, infants and children.

    PubMed

    Yunus, Mahira

    2012-11-01

    To study the use of helical computed tomography 2-D and 3-D images, and virtual endoscopy in the evaluation of airway disease in neonates, infants and children and its value in lesion detection, characterisation and extension. Conducted at Al-Noor Hospital, Makkah, Saudi Arabia, from January 1 to June 30, 2006, the study comprised of 40 patients with strider, having various causes of airway obstruction. They were examined by helical CT scan with 2-D and 3-D reconstructions and virtual endoscopy. The level and characterisation of lesions were carried out and results were compared with actual endoscopic findings. Conventional endoscopy was chosen as the gold standard, and the evaluation of endoscopy was done in terms of sensitivity and specificity of the procedure. For statistical purposes, SPSS version 10 was used. All CT methods detected airway stenosis or obstruction. Accuracy was 98% (n=40) for virtual endoscopy, 96% (n=48) for 3-D external rendering, 90% (n=45) for multiplanar reconstructions and 86% (n=43) for axial images. Comparing the results of 3-D internal and external volume rendering images with conventional endoscopy for detection and grading of stenosis were closer than with 2-D minimum intensity multiplanar reconstruction and axial CT slices. Even high-grade stenosis could be evaluated with virtual endoscope through which conventional endoscope cannot be passed. A case of 4-year-old patient with tracheomalacia could not be diagnosed by helical CT scan and virtual bronchoscopy which was diagriosed on conventional endoscopy and needed CT scan in inspiration and expiration. Virtual endoscopy [VE] enabled better assessment of stenosis compared to the reading of 3-D external rendering, 2-D multiplanar reconstruction [MPR] or axial slices. It can replace conventional endoscopy in the assessment of airway disease without any additional risk.

  2. Evaluation of the sensitivity of scout radiographs on unenhanced helical CT in identifying ureteric calculi: a large UK tertiary referral centre experience

    PubMed Central

    Yap, W W; Belfield, J C; Bhatnagar, P; Kennish, S; Wah, T M

    2012-01-01

    Objective Unenhanced helical CT for kidney, ureter and bladder (CT KUB) has become the standard investigation for renal colic. This study aims to determine the sensitivity of scout radiographs in detecting ureteric calculi using CT KUB as a standard reference. Methods A retrospective review of consecutive patients who presented with acute flank pain and were investigated using CT KUB. 201 patients with positive ureteric calculi were included. Two radiologists independently reviewed the scout radiographs with access to CT KUB images. Each observer recorded the presence or absence of calculi, location, size and mean Hounsfield units of each calculus. Results 203 ureteric calculi were analysed from 201 patients. The overall sensitivity of scout radiographs for Observer A was 42.3% and for Observer B 52.2%, with an interobserver reliability κ-value of 0.78. The significance of mean Hounsfield units and size between two groups of patients with visible stones and those not visible were tested; the p-value for both variables was <0.0001, which is statistically significant. The study found that calculi in the upper ureter and larger than 4 mm are more likely to be seen on the scout radiograph. Conclusions Usage of CT scout radiography should be encouraged and reported routinely in conjunction with CT KUB as a baseline for treatment follow-up. PMID:22665926

  3. Patient radiation dose in prospectively gated axial CT coronary angiography and retrospectively gated helical technique with a 320-detector row CT scanner

    SciTech Connect

    Seguchi, Shigenobu; Aoyama, Takahiko; Koyama, Shuji; Fujii, Keisuke; Yamauchi-Kawaura, Chiyo

    2010-11-15

    Purpose: The aim of this study was to evaluate radiation dose to patients undergoing computed tomography coronary angiography (CTCA) for prospectively gated axial (PGA) technique and retrospectively gated helical (RGH) technique. Methods: Radiation doses were measured for a 320-detector row CT scanner (Toshiba Aquilion ONE) using small sized silicon-photodiode dosimeters, which were implanted at various tissue and organ positions within an anthropomorphic phantom for a standard Japanese adult male. Output signals from photodiode dosimeters were read out on a personal computer, from which organ and effective doses were computed according to guidelines published in the International Commission on Radiological Protection Publication 103. Results: Organs that received high doses were breast, followed by lung, esophagus, and liver. Breast doses obtained with PGA technique and a phase window width of 16% at a simulated heart rate of 60 beats per minute were 13 mGy compared to 53 mGy with RGH technique using electrocardiographically dependent dose modulation at the same phase window width as that in PGA technique. Effective doses obtained in this case were 4.7 and 20 mSv for the PGA and RGH techniques, respectively. Conversion factors of dose length product to the effective dose in PGA and RGH were 0.022 and 0.025 mSv mGy{sup -1} cm{sup -1} with a scan length of 140 mm. Conclusions: CTCA performed with PGA technique provided a substantial effective dose reduction, i.e., 70%-76%, compared to RGH technique using the dose modulation at the same phase windows as those in PGA technique. Though radiation doses in CTCA with RGH technique were the same level as, or some higher than, those in conventional coronary angiography (CCA), the use of PGA technique reduced organ and effective doses to levels less than CCA except for breast dose.

  4. Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy

    PubMed Central

    Cheng, K-F

    2014-01-01

    Objective: Effective immobilization is crucial for the accurate delivery of radiotherapy. This study aimed to compare the effectiveness of the commonly used immobilization systems for different body regions using megavoltage CT (MVCT). Methods: Daily treatment set-up data from 212 patients treated by helical tomotherapy (Accuray, Sunnyvale, CA) in 6 body regions (52 head and neck, 41 chest, 38 abdomen, 36 pelvis, 18 breast and 27 cranium) were obtained. Based on a verification tool using the pre-treatment MVCT, set-up corrections for each patient were recorded. Mean systematic and random errors of lateral, longitudinal, vertical and roll directions and three-dimensional vectors were compared between immobilization systems of each region. Results: Smaller set-up deviations were observed in the Orfit system (Orfit Industries NV, Wijnegem, Belgium) of the head and neck region, while the performance of immobilization systems for the chest, abdomen and pelvis regions was similar. Larger differences were noted in the breast group, where the prone BodyFIX® system (Medical Intelligence, Medizintechnik GmbH, Schwabmünchen, Germany) was less stable than the supine VacLok® system (CIVCO Medical Solutions, Orange City, IA). Conclusion: Differences were found between the immobilization systems in the head and neck region, in which the Orfit system was relatively more effective, whereas the VacLok and BodyFIX systems performed similarly in the chest, abdomen and pelvis regions. For the breast case, the supine position with VacLok was much more stable than the prone breast technique. The results provided references for the estimation of clinical target volume–planning target volume margins. Advances in knowledge: This is the first article on comprehensive comparisons performed in immobilization systems for main body regions that provides some practical recommendations. PMID:24398111

  5. [First diagnostic choice in patients with high clinical suspicion of pulmonary thromboembolism: helical CT or ventilation/perfusion pulmonary scintigraphy?].

    PubMed

    Ferrán, N; Martín-Comín, J; Bajén, M; Carrera, D; Mora, J; Ricart, Y; Sánchez, F; Mast, R

    2005-01-01

    Comparative analysis about helical CT (ThC) vs ventilation-perfusion pulmonary scintigraphy (V/P Sc) diagnosis effectiveness, as a first diagnosis technique in patients with high clinical suspicion of pulmonary thromboembolism (PT). Prospective study of 30 patients with high clinical suspicion and high Dimer-D levels (> 250 microg/l). The diagnosis was defined as anticoagulant therapeutic prescription and posterior clinical evolution. V/P Sc were performed to each patient within the next 48 h (an average of 14.8 h) after TCh, without anticoagulant treatment. We classified the scintigrams according to the PIOPED criteria and hTC images as positive, negative and indeterminated. In sixteen patients final diagnosis was PT: in 9 both techniques were positive; in 5 scintigraphy was positive with normal hTC and in 1, hTC was normal with negative scintigraphy. The last case was an indeterminated hTC with negative scintigraphy. In fourteen patients, final diagnosis was non-PT: in 6 both techniques were negative; in 7 scintigraphy was negative with positive hTC and in 1, both results were indeterminated. The sensitivity, specificity, positive predictive value, negative predictive value and efficiency were respectively 87.5, 100, 100, 87.5 and 93 % for V/P Sc and 62, 50, 58.8, 53.8 and 53 % for TCh. V/P Sc has better PT diagnosis reliability. It is recommended to do V/P Sc in all patients with high clinical suspicion of PT.

  6. Frequency, sensitivity, and specificity of individual signs of diverticulitis on thin-section helical CT with colonic contrast material: experience with 312 cases.

    PubMed

    Kircher, Moritz F; Rhea, James T; Kihiczak, Danylo; Novelline, Robert A

    2002-06-01

    The aim of our study was to determine the frequency, sensitivity, and specificity of the individual signs of diverticulitis using helical CT with colonic contrast material. Between March 1997 and September 1999, 312 patients with suspected diverticulitis were examined on helical CT using rectally administered colonic contrast material. CT scans that were positive for diverticulitis or indeterminate were rereviewed by two radiologists; CT interpretations were correlated with patients' clinical courses and surgical findings. One hundred fourteen (37%) of the 312 CT scans were interpreted as positive for diverticulitis; 192 scans (61%), as negative; six scans (2%), as indeterminate. Of the 114 scans that were positive for diverticulitis, 109 (96%; sensitivity 96%, specificity 91%) showed bowel wall thickening; 108 (95%; sensitivity 96%, specificity 90%), fat stranding; 104 (91%; sensitivity 91%, specificity 67%), diverticula; 57 (50%; sensitivity 50%, specificity 100%), fascial thickening; 51 (45%; sensitivity 45%, specificity 97%), free fluid; 49 (43%; sensitivity 43%, specificity 100%), inflamed diverticula; 34 (30%; sensitivity 30%, specificity 100%), free air; 18 (16%; sensitivity 16%, specificity 100%), "arrowhead" signs; nine (8%; sensitivity 8%, specificity 99%), abscesses; four (4%; sensitivity 4%, specificity 100%,), phlegmons; five (4%; sensitivity 4%, specificity 99%), intramural air; two (2%; sensitivity 2%, specificity 100%), intramural sinus tracts. Overall CT interpretation had a sensitivity of 99%, a specificity of 99%, a positive predictive value of 99%, a negative predictive value of 99%, and an overall accuracy of 99%. The two most frequent signs of diverticulitis were bowel wall thickening (96%) and fat stranding (95%). Less frequent but highly specific signs were fascial thickening (50%), free fluid (45%), and inflamed diverticula (43%).

  7. Scan time and patient dose for thoracic imaging in neonates and small children using axial volumetric 320-detector row CT compared to helical 64-, 32-, and 16- detector row CT acquisitions.

    PubMed

    Kroft, Lucia J M; Roelofs, Joost J H; Geleijns, Jacob

    2010-03-01

    Recently a 320-detector-row CT (MDCT) scanner has become available that allows axial volumetric scanning of a 16-cm-long range (50 cm field of view) in a single 0.35-s rotation. For imaging neonates and small children, volume scanning is potentially of great advantage as the entire scan range can be acquired in 0.35 s, which can reduce motion artefacts and may reduce the need for sedation in clinical CT imaging. Also, because there is no over-ranging associated with axial volumetric scanning, this may reduce patient radiation dose. To evaluate, by means of a phantom study, scan time and patient dose for thoracic imaging in neonates and small children by using axial cone-beam and helical fan-beam MDCT acquisitions. Paediatric imaging protocols were assessed for a 320-MDCT volumetric scanner (Aquilion ONE, Toshiba, Otawara, Japan). The 320-MDCT scanner allows for cone-beam acquisitions with coverage up to 160 mm, but it also allows for helical fan-beam acquisitions in 64-, 32-, or 16-MDCT modes. The acquisition configurations that were evaluated were 320 x 0.5 mm, 240 x 0.5 mm, and 160 x 0.5 mm for axial volumetric scanning, and 64 x 0.5 mm, 32 x 0.5 mm, and 16 x 0.5 mm for helical scanning. Dose assessment was performed for clinically relevant paediatric angiographic or chest/mediastinum acquisition protocols with tube voltages of 80 or 100 kVp and tube currents between 40 and 80 mA. Scan time was 0.35 s for 320-MDCT acquisitions, scan times varied between 1.9 s and 8.3 s for helical acquisitions. Dose savings varying between 18% and 40% were achieved with axial volumetric scanning as compared to helical scanning (for 320- versus 64-MDCT at 160 mm and 80 kVp, and for 320- versus 16-MDCT at 80 mm and 100 kVp, respectively). Statistically significant reduction in radiation dose was found for axial 320-MDCT volumetric scanning compared to helical 64-, 32-, and 16-MDCT scanning. Axial thoracic CT of neonates and small children with volumetric 320-MDCT can be performed

  8. MTHFR c.677C>T is a risk factor for non-syndromic cleft lip with or without cleft palate in Chile.

    PubMed

    Ramírez-Chau, C; Blanco, R; Colombo, A; Pardo, R; Suazo, J

    2016-10-01

    The functional variant within the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene c.677C>T, producing alterations in folate metabolism, has been associated with the risk of non-syndromic cleft lip with or without cleft palate (NSCL/P). We assessed this association in a Chilean population using a combined analysis of case-control and case-parent trio samples. Samples of 165 cases and 291 controls and 121 case-parent trios (sharing the cases) were genotyped. Odds ratio (OR) was estimated for case-control (allele and genotype frequency differences), and this result was confirmed by allele transmission distortion in trios. Due to that these samples are not independent, a combined OR was also computed. Maternal genotype effect was additionally evaluated based on a log-linear method. Borderline but not significant OR (1.28; CI 0.97-1.69) was observed for risk allele (T) in the case-control sample. However, triad sample showed a significant association (OR 1.56: CI 1.09-2.25) which was confirmed by the combined OR (1.37; CI 1.11-1.71). Maternal genotype has been also associated with the phenotype (P = 0.002). In contrast to previous reports considering Chilean subjects, our results demonstrated that the offspring and maternal genotypes for MTHFR c.677C>T variant are strongly associated with NSCL/P in this Chilean population. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Novel homozygous mutation, c.400C>T (p.Arg134*), in the PVRL1 gene underlies cleft lip/palate-ectodermal dysplasia syndrome in an Asian patient.

    PubMed

    Yoshida, Kazue; Hayashi, Ryota; Fujita, Hideki; Kubota, Masaya; Kondo, Mai; Shimomura, Yutaka; Niizeki, Hironori

    2015-07-01

    Cleft lip/palate-ectodermal dysplasia syndrome is a rare, autosomal recessive disorder caused by homozygous loss-of-function mutations of the poliovirus receptor-like 1 (PVRL1) gene encoding nectin-1. Nectin-1 is a cell-cell adhesion molecule that is important for the initial step in the formation of adherens junctions and tight junctions; it is expressed in keratinocytes, neurons, and the developing face and palate. Clinical manifestations comprise a unique facial appearance with cleft lip/palate, ectodermal dysplasia, cutaneous syndactyly of the fingers and/or toes, and in some cases, mental retardation. We present the first report, to our knowledge, of an Asian individual with cleft lip/palate-ectodermal dysplasia syndrome with a novel PVRL1 mutation. A 7-year-old Japanese boy, the first child of a consanguineous marriage, showed hypohidrotic ectodermal dysplasia with sparse, brittle, fine, dry hair and hypodontia, the unique facial appearance with cleft lip/palate, cutaneous syndactyly of the fingers and mild mental retardation. Scanning electron microscopic examination of the hair demonstrated pili torti and pili trianguli et canaliculi. Mutation analysis of exon 2 of PVRL1 revealed a novel homozygous nonsense mutation, c.400C>T (p.Arg134*). His parents were heterozygous for the mutant alleles. All four PVRL1 mutations identified in cleft lip/palate-ectodermal dysplasia syndrome to date, including this study, resulted in truncated proteins that lack the transmembrane domain and intracellular domain of nectin-1, which is necessary to initiate the cell-cell adhesion process. © 2015 Japanese Dermatological Association.

  10. 11C-choline PET/CT based helical tomotherapy as treatment approach for bone metastases in recurrent prostate cancer patients.

    PubMed

    Incerti, Elena; Gangemi, Vincenzo; Mapelli, Paola; Deantoni, Chiara Lucrezia; Giovacchini, Giampiero; Fallanca, Federico; Fodor, Andrei; Ciarmiello, Andrea; Baldari, Sergio; Gianolli, Luigi; Di Muzio, Nadia; Picchio, Maria

    2017-09-19

    To evaluate the efficacy of 11C-choline PET/CT (CHO-PET/CT) based helical tomotherapy (HTT) as a therapeutic approach for bone metastases in recurrent prostate cancer (PCa) patients. METHODS This retrospective study includes 20 PCa patients (median age: 67; range: 51-80 years) presenting biochemical relapse after primary treatment who underwent CHO-PET/CT based HTT on positive bone metastases from December 2007 to June 2014. The effectiveness of HTT assessed with biochemical response at 3/6/12 months, biochemical relapse free survival (bRFS) and overall survival (OS) at 2 years. Toxicity has been also considered and assessed according to Common Terminology Criteria for Adverse Events (CTCAE). RESULTS All patients presented a relapse at the time of CHO-PET/CT at bone metastases. In addition 15/20 (75%) also at lymph nodes (LNs) level (total lesions= 54). All patients underwent HTT on bone metastases and 19/20 concomitantly on prostatic bed and LNs. The median follow-up from CHO-PET/CT was 2 years (range: 1-7 years). At 3 months, after the beginning of HTT treatment, complete or partial biochemical response occurred in 79% of patients, at 6 months in 82% and at 12 months in 63% of patients. bRFS and OS at 2 years were 50% and 55% of patients, respectively. Patients presented mostly grade 1 or 2 toxicity according to CTCAE. The only grade 3 late toxicity has been observed in one patient. CONCLUSIONS CHO-PET/CT based HTT is a suitable therapeutic approach in patients with recurrent PCa presenting bone metastases with a medium-low toxicity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Role and pitfalls of hepatic helical multi-phase CT scanning in differential diagnosis of small hemangioma and small hepatocellular carcinoma

    PubMed Central

    Yan, Fu-Hua; Zeng, Meng-Su; Zhou, Kang-Rong

    1998-01-01

    AIM: To compare and analyze the contrast enhancement appearance of small hemangioma (SHHE) and small hepatocellular carcinoma (SHCC) with helical multi-phase CT scanning so as to determine their roles and pitfalls in the differential diagnosis of SHHE and SHCC. METHODS: The pre and postcontrast CT scanning of the liver in 73 cases (38 SHHE, 35 SHCC) were carried out. The first phase scan of the entire liver began at 30s after the injection of contrast medium, the second and third phases began at 70s, and 4 min respectively. The contrast enhancement patterns and characteristics of all lesions were observed and compared. RESULTS: In SHHE, 64.29% (27/42) had typical manifestations in two-phase dynamic scanning, such as peripheral dramatic high-density enhancement of the lesions with progressive opacification from the periphery toward the center, 30.95% (13/42) were hyperdense in both phases and 4.76% (2/42) were hypodense in both phases. In the third phase scanning, 96.67% (28/30) of SHHE were hyperdense and isodense. In SHCC 59.52% (25/42) presented typical appearances, such as hyperdense in the first phase and hypodense in the second phase, 23.81% (10/42) were hyperdense in the first phase and isodense in the second phase with 4.76% (2/42) of hypodense in both phases. In the third phase scanning, 85.71% (24/28) of SHCC were hypodense. CONCLUSION: According to the contrast enhancement patterns of SHHE and SHCC in the two-phase or multi-phase scanning by helical CT, diagnosis can be established in the majority of lesions, while some atypical cases needed MRI for further investigation. PMID:11819317

  12. Role and pitfalls of hepatic helical multi-phase CT scanning in differential diagnosis of small hemangioma and small hepatocellular carcinoma.

    PubMed

    Yan, Fu-Hua; Zeng, Meng-Su; Zhou, Kang-Rong

    1998-08-01

    AIM:To compare and analyze the contrast enhancement appearance of small hemangioma (SHHE) and small hepatocellular carcinoma (SHCC) with helical multi-phase CT scanning so as to determine their roles and pitfalls in the differential diagnosis of SHHE and SHCC.METHODS:The pre and postcontrast CT scanning of the liver in 73 cases (38 SHHE, 35 SHCC) were carried out. The first phase scan of the entire liver began at 30s after the injection of contrast medium, the second and third phases began at 70s, and 4min respectively. The contrast enhancement patterns and characteristics of all lesions were observed and compared.RESULTS In SHHE, 64.29% (27/42) had typical manifestations in two-phase dynamic scanning, such as peripheral dramatic high-density enhancement of the lesions with progressive opacification from the periphery toward the center, 30.95% (13/42) were hyperdense in both phases and 4.76% (2/42) were hypodense in both phases. In the third phase scanning, 96.67% (28/30) of SHHE were hyperdense and isodense.In SHCC 59.52% (25/42) presented typical appearances, such as hyperdense in the first phase and hypodense in the second phase, 23.81% (10/42) were hyperdense in the first phase and isodense in the second phase with 4.76% (2/42) of hypodense in both phases. In the third phase scanning, 85.71% (24/28) of SHCC were hypodense.CONCLUSION:According to the contrast enhancement patterns of SHHE and SHCC in the two-phase or multi-phase scanning by helical CT, diagnosis can be established in the majority of lesions, while some atypical cases needed MRI for further investigation.

  13. Palatal myoclonus

    MedlinePlus

    ... hearing Alternative Names Palatal tremor References Jankovic J. Movement disorders. In: Daroff RB, Fenichel GM, Jankovic J, eds. ... Editorial team. Related MedlinePlus Health Topics Mouth Disorders Movement Disorders Multiple Sclerosis Browse the Encyclopedia A.D.A. ...

  14. Computerized lung nodule detection: comparison of performance for low-dose and standard-dose helical CT scans

    NASA Astrophysics Data System (ADS)

    Armato, Samuel G., III; Giger, Maryellen L.; Doi, Kunio; Bick, Ulrich; MacMahon, Heber

    2001-07-01

    The vast amount of image data acquired during a computed tomography (CT) scan makes lung nodule detection a burdensome task. Moreover, the growing acceptance of low-dose CT for lung cancer screening promises to further impact radiologists' workloads. Therefore, we have developed a computerized method to automatically analyze structures within a CT scan and identify those structures that represent lung nodules. Gray-level thresholding is performed to segment the lungs in each section to produce a segmented lung volume, which is then iteratively thresholded. At each iteration, remaining voxels are grouped into contiguous three-dimensional structures. Structures that satisfy a volume criterion then become nodule candidates. The set of nodule candidates is subjected to feature analysis. To distinguish candidates representing nodule and non-nodule structures, a rule-based approach is combined with an automated classifier. This method was applied to 43 standard-dose (diagnostic) CT scans and 13 low-dose CT scans. The method achieved an overall detection sensitivity of 71% with 1.5 false-positive detections per section on the standard-dose database and 71% sensitivity with 1.2 false-positive detections per section on the low-dose database. This automated method demonstrates promising performance in its ability to accurately detect lung nodules in standard-dose and low-dose CT images.

  15. SU-E-I-15: Quantitative Evaluation of Dose Distributions From Axial, Helical and Cone-Beam CT Imaging by Measurement Using a Two-Dimensional Diode-Array Detector

    SciTech Connect

    Chacko, M; Aldoohan, S; Sonnad, J; Ahmad, S; Ali, I

    2015-06-15

    Purpose: To evaluate quantitatively dose distributions from helical, axial and cone-beam CT clinical imaging techniques by measurement using a two-dimensional (2D) diode-array detector. Methods: 2D-dose distributions from selected clinical protocols used for axial, helical and cone-beam CT imaging were measured using a diode-array detector (MapCheck2). The MapCheck2 is composed from solid state diode detectors that are arranged in horizontal and vertical lines with a spacing of 10 mm. A GE-Light-Speed CT-simulator was used to acquire axial and helical CT images and a kV on-board-imager integrated with a Varian TrueBeam-STx machine was used to acquire cone-beam CT (CBCT) images. Results: The dose distributions from axial, helical and cone-beam CT were non-uniform over the region-of-interest with strong spatial and angular dependence. In axial CT, a large dose gradient was measured that decreased from lateral sides to the middle of the phantom due to large superficial dose at the side of the phantom in comparison with larger beam attenuation at the center. The dose decreased at the superior and inferior regions in comparison to the center of the phantom in axial CT. An asymmetry was found between the right-left or superior-inferior sides of the phantom which possibly to angular dependence in the dose distributions. The dose level and distribution varied from one imaging technique into another. For the pelvis technique, axial CT deposited a mean dose of 3.67 cGy, helical CT deposited a mean dose of 1.59 cGy, and CBCT deposited a mean dose of 1.62 cGy. Conclusions: MapCheck2 provides a robust tool to measure directly 2D-dose distributions for CT imaging with high spatial resolution detectors in comparison with ionization chamber that provides a single point measurement or an average dose to the phantom. The dose distributions measured with MapCheck2 consider medium heterogeneity and can represent specific patient dose.

  16. Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

    SciTech Connect

    Yang, Claus; Liu Tianxiao; Jennelle, Richard L.; Ryu, Janice K.; Vijayakumar, Srinivasan; Purdy, James A.; Chen, Allen M.

    2010-07-01

    The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her original kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive

  17. Dose calculation software for helical tomotherapy, utilizing patient CT data to calculate an independent three-dimensional dose cube

    SciTech Connect

    Thomas, Simon J.; Eyre, Katie R.; Tudor, G. Samuel J.; Fairfoul, Jamie

    2012-01-15

    Purpose: Treatment plans for the TomoTherapy unit are produced with a planning system that is integral to the unit. The authors have produced an independent dose calculation system, to enable plans to be recalculated in three dimensions, using the patient's CT data. Methods: Software has been written using MATLAB. The DICOM-RT plan object is used to determine the treatment parameters used, including the treatment sinogram. Each projection of the sinogram is segmented and used to calculate dose at multiple calculation points in a three-dimensional grid using tables of measured beam data. A fast ray-trace algorithm is used to determine effective depth for each projection angle at each calculation point. Calculations were performed on a standard desktop personal computer, with a 2.6 GHz Pentium, running Windows XP. Results: The time to perform a calculation, for 3375 points averaged 1 min 23 s for prostate plans and 3 min 40 s for head and neck plans. The mean dose within the 50% isodose was calculated and compared with the predictions of the TomoTherapy planning system. When the modified CT (which includes the TomoTherapy couch) was used, the mean difference for ten prostate patients, was -0.4% (range -0.9% to +0.3%). With the original CT (which included the CT couch), the mean difference was -1.0% (range -1.7% to 0.0%). The number of points agreeing with a gamma 3%/3 mm averaged 99.2% with the modified CT, 96.3% with the original CT. For ten head and neck patients, for the modified and original CT, respectively, the mean difference was +1.1% (range -0.4% to +3.1%) and 1.1% (range -0.4% to +3.0%) with 94.4% and 95.4% passing a gamma 4%/4 mm. The ability of the program to detect a variety of simulated errors has been tested. Conclusions: By using the patient's CT data, the independent dose calculation performs checks that are not performed by a measurement in a cylindrical phantom. This enables it to be used either as an additional check or to replace phantom

  18. Generation of hybrid sinograms for the recovery of kV-CT images with metal artifacts for helical tomotherapy

    SciTech Connect

    Jeon, Hosang; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Yong Ho; Lee, Ju Hye; Kim, Dongwon; Youn, Hanbean; Nam, Jiho; Lee, Jayoung; Kim, Ho Kyung

    2015-08-15

    Purpose: The overall goal of this study is to restore kilovoltage computed tomography (kV-CT) images which are disfigured by patients’ metal prostheses. By generating a hybrid sinogram that is a combination of kV and megavoltage (MV) projection data, the authors suggest a novel metal artifact-reduction (MAR) method that retains the image quality to match that of kV-CT and simultaneously restores the information of metal prostheses lost due to photon starvation. Methods: CT projection data contain information about attenuation coefficients and the total length of the attenuation. By normalizing raw kV projections with their own total lengths of attenuation, mean attenuation projections were obtained. In the same manner, mean density projections of MV-CT were obtained by the normalization of MV projections resulting from the forward projection of density-calibrated MV-CT images with the geometric parameters of the kV-CT device. To generate the hybrid sinogram, metal-affected signals of the kV sinogram were identified and replaced by the corresponding signals of the MV sinogram following a density calibration step with kV data. Filtered backprojection was implemented to reconstruct the hybrid CT image. To validate the authors’ approach, they simulated four different scenarios for three heads and one pelvis using metallic rod inserts within a cylindrical phantom. Five inserts describing human body elements were also included in the phantom. The authors compared the image qualities among the kV, MV, and hybrid CT images by measuring the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), the densities of all inserts, and the spatial resolution. In addition, the MAR performance was compared among three existing MAR methods and the authors’ hybrid method. Finally, for clinical trials, the authors produced hybrid images of three patients having dental metal prostheses to compare their MAR performances with those of the kV, MV, and three existing MAR

  19. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans.

    PubMed

    Dauer, Lawrence T; Casciotta, Kevin A; Erdi, Yusuf E; Rothenberg, Lawrence N

    2007-03-16

    It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0-15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

  20. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

    PubMed Central

    Dauer, Lawrence T; Casciotta, Kevin A; Erdi, Yusuf E; Rothenberg, Lawrence N

    2007-01-01

    Background It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. Methods The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. Results The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Conclusion Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans. PMID:17367529

  1. Lung cancer screening with low-dose helical CT in Korea: experiences at the Samsung Medical Center.

    PubMed

    Chong, Semin; Lee, Kyung Soo; Chung, Myung Jin; Kim, Tae Sung; Kim, Hojoong; Kwon, O Jung; Choi, Yoon-Ho; Rhee, Chong H

    2005-06-01

    To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with >or=45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (>or=20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.

  2. Cardiac helical CT involving a low-radiation-dose protocol with a 100-kVp setting

    PubMed Central

    Iyama, Yuji; Nakaura, Takeshi; Yokoyama, Koichi; Kidoh, Masafumi; Yamashita, Yasuyuki

    2016-01-01

    Abstract To compare the radiation dose and image quality of retrospective electrocardiogram (ECG)-gated cardiac computed tomography (CT) between a 100-kVp protocol, hybrid iterative reconstruction (HIR), and display preset optimization and the 120-kVp protocol. We prospectively enrolled 100 patients with tachycardia or atrial fibrillation scanned retrospective ECG-gated cardiac CT. We randomly assigned 50 patients to the 120-kVp protocol and 50 patients to the 100-kVp protocol. We compared effective doses (EDs) between the two protocols. The 120-kVp images were post-processed using filtered back projection (FBP). The 100-kVp images were post-processed using FBP (100-kVp protocol) and HIR (i-100-kVp protocol). We compared attenuation of the ascending aorta, signal-to-noise ratio (SNR), and image noise between the 120-kVp, 100-kVp, and i-100-kVp protocols. We performed qualitative image analysis for the 120-kVp and i-100-kVp protocols. ED of the 100-kVp protocol (4.4 ± 0.4 mSv) was 76% lower than that of the 120-kVp protocol (18.4 ± 0.6 mSv). Attenuations of the 100-kVp (549.1 ± 73.8 HU) and i-100-kVp (550.5 ± 73.7 HU) protocols were higher than that of the120-kVp protocol (437.3 ± 55.7 HU). Image noise of the 100-kVp (53.6 ± 18.5 HU) and i-100-kVp (30.9 ± 8.6 HU) protocols were higher than that of the120-kVp protocol (23.8 ± 5.7 HU). There was no significant difference in SNR and the result of qualitative image analysis between the 120-kVp and i-100-kVp protocols. The 100-kVp protocol with HIR reduced the 76% radiation dose while preserving the image quality compared with the conventional 120-kVp protocol on retrospective ECG-gated cardiac CT. PMID:27861400

  3. Cleft palate - resources

    MedlinePlus

    Resources - cleft palate ... The following organizations are good resources for information on cleft palate : Cleft Palate Foundation -- www.cleftline.org March of Dimes -- www.marchofdimes.com/professionals/14332_1210.asp ...

  4. Automatic registration of megavoltage to kilovoltage CT images in helical tomotherapy: An evaluation of the setup verification process for the special case of a rigid head phantom

    SciTech Connect

    Boswell, Sarah; Tome, Wolfgang; Jeraj, Robert; Jaradat, Hazim; Mackie, T. Rock

    2006-11-15

    Precise daily target localization is necessary to achieve highly conformal radiation delivery. In helical tomotherapy, setup verification may be accomplished just prior to delivering each fraction by acquiring a megavoltage CT scan of the patient in the treatment position. This daily image set may be manually or automatically registered to the image set on which the treatment plan was calculated, in order to determine any needed adjustments. The system was tested by acquiring 104 MVCT scans of an anthropomorphic head phantom to which translational displacements had been introduced with respect to the planning image set. Registration results were compared against an independent, optically guided positioning system. The total experimental uncertainty was within approximately 1 mm. Although the registration of phantom images is not fully analogous to the registration of patient images, this study confirms that the system is capable of phantom localization with sub-voxel accuracy. In seven registration problems considered, expert human observers were able to perform manual registrations with comparable or inferior accuracy to automatic registration by mutual information. The time to compute an automatic registration is considerably shorter than the time required for manual registration. However, human evaluation of automatic results is necessary in order to identify occasional outliers, and to ensure that the registration is clinically acceptable, especially in the case of deformable patient anatomy.

  5. Helicity scalings

    NASA Astrophysics Data System (ADS)

    Plunian, F.; Lessinnes, T.; Carati, D.; Stepanov, R.

    2011-12-01

    Using a helical shell model of turbulence, Chen et al. (2003) showed that both helicity and energy dissipate at the Kolmogorov scale, independently from any helicity input. This is in contradiction with a previous paper by Ditlevsen & Giuliani (2001) in which, using a GOY shell model of turbulence, they found that helicity dissipates at a scale larger than the Kolmogorov scale, and does depend on the helicity input. In a recent paper by Lessinnes et al. (2011), we showed that this discrepancy is due to the fact that in the GOY shell model only one helical mode (+ or -) is present at each scale instead of both modes in the helical shell model. Then, using the GOY model, the near cancellation of the helicity flux between the + and - modes cannot occur at small scales, as it should be in true turbulence. We review the main results with a focus on the numerical procedure needed to obtain accurate statistics.

  6. Cleft palate caused by congenital teratoma.

    PubMed

    Veyssière, Alexis; Streit, Libor; Traoré, Hamady; Bénateau, Hervé

    2017-02-01

    A cleft palate results from incomplete fusion of the lateral palatine processes, the median nasal septum and the median palatine process. This case report describes a rare case of congenital teratoma originating from the nasal septum that may have interfered with the fusion of the palatal shelves during embryonic development, resulting in a cleft palate. An infant girl was born at 40 weeks of gestation weighing 3020 g with a complete cleft palate associated with a large central nasopharyngeal tumour. Computed tomography (CT) of the head showed a well defined mass of mixed density. The tumour was attached to the nasal septum in direct contact with the cleft palate. A biopsy confirmed the teratoma. Tumour resection was performed at 5 months, soft palate reconstruction at 7 months and hard palate closure at 14 months. There was no sign of local recurrence 1 year later. Most teratomas are benign and the prognosis is usually good. However, recurrence is not rare if germ cell carcinomatous foci are present within the teratoma. For these reasons, we advocate the use of a two-stage procedure in which closure of the cleft palate is postponed until histological examination confirms complete excision of the teratoma.

  7. A Novel Fast Helical 4D-CT Acquisition Technique to Generate Low-Noise Sorting Artifact–Free Images at User-Selected Breathing Phases

    SciTech Connect

    Thomas, David; Lamb, James; White, Benjamin; Jani, Shyam; Gaudio, Sergio; Lee, Percy; Ruan, Dan; McNitt-Gray, Michael; Low, Daniel

    2014-05-01

    Purpose: To develop a novel 4-dimensional computed tomography (4D-CT) technique that exploits standard fast helical acquisition, a simultaneous breathing surrogate measurement, deformable image registration, and a breathing motion model to remove sorting artifacts. Methods and Materials: Ten patients were imaged under free-breathing conditions 25 successive times in alternating directions with a 64-slice CT scanner using a low-dose fast helical protocol. An abdominal bellows was used as a breathing surrogate. Deformable registration was used to register the first image (defined as the reference image) to the subsequent 24 segmented images. Voxel-specific motion model parameters were determined using a breathing motion model. The tissue locations predicted by the motion model in the 25 images were compared against the deformably registered tissue locations, allowing a model prediction error to be evaluated. A low-noise image was created by averaging the 25 images deformed to the first image geometry, reducing statistical image noise by a factor of 5. The motion model was used to deform the low-noise reference image to any user-selected breathing phase. A voxel-specific correction was applied to correct the Hounsfield units for lung parenchyma density as a function of lung air filling. Results: Images produced using the model at user-selected breathing phases did not suffer from sorting artifacts common to conventional 4D-CT protocols. The mean prediction error across all patients between the breathing motion model predictions and the measured lung tissue positions was determined to be 1.19 ± 0.37 mm. Conclusions: The proposed technique can be used as a clinical 4D-CT technique. It is robust in the presence of irregular breathing and allows the entire imaging dose to contribute to the resulting image quality, providing sorting artifact–free images at a patient dose similar to or less than current 4D-CT techniques.

  8. Detection of liver metastases by pulse inversion harmonic imaging during Levovist late phase: comparison with conventional ultrasound and helical CT in 160 patients.

    PubMed

    Quaia, Emilio; Bertolotto, Michele; Forgács, Balázs; Rimondini, Alessandra; Locatelli, Martina; Mucelli, Roberto Pozzi

    2003-03-01

    The aim of this study was to evaluate capabilities of pulse inversion harmonic imaging (PIHI) with Levovist in detection of liver metastases compared with conventional ultrasound (US) and helical CT (HCT). One hundred sixty consecutive patients with known malignancies were evaluated by conventional US, PIHI 2 min (40 patients) or 4 min (120 patients) after Levovist injection and HCT. Conspicuity and number of the identified metastatic lesions were evaluated and assessed by statistical analysis (significance p<0.05). Mean diameter of the smallest identified metastases was computed for conventional US, PIHI and HCT. In cases where PIHI revealed more lesions suspicious for metastases than HCT, intraopertive US with surgical biopsy or 3-6-month US follow-up were performed to confirm diagnosis. Images were stored on magneto-optical disk and evaluated off-line by a dedicated software. Metastases conspicuity was significantly improved on PIHI if compared with conventional US ( p<0.05). In 49 patients all the employed imaging techniques did not reveal any lesion, whereas in the remaining 111 patients, 28 patients revealed more than five metastatic lesions and 83 patients presented from one to five metastatic lesions. In comparison with conventional US, PIHI revealed more metastases in 39/83 (47%), the same number in 44/83 (53%) and a lower number in 0/83 (0%) patients. In comparison with HCT, PIHI revealed more metastases in 10/83 (12%), the same number in 61/83 (74%) and a lower number in 12/83 (14%) patients. Average number +/- SD (standard deviation) of confirmed metastases for patients was 2.21+/-1.6 for conventional US, 3.1+/-2.44 for PIHI and 3.05+/-2.41 for HCT. The difference between PIHI and conventional US was statistically significant ( p<0.0001), whereas the difference between PIHI and HCT was not significant ( p=0.9). The smallest identified metastases presented 3-mm mean diameter on PIHI, 5-mm on HCT and 7-mm on conventional US. PIHI with Levovist is a

  9. Cleft lip and palate

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/001051.htm Cleft lip and palate To use the sharing features on this page, please enable JavaScript. Cleft lip and palate are birth defects that affect the upper lip ...

  10. Relationship between palate-vomer development and maxillary growth in submucous cleft palate patients.

    PubMed

    Ren, Shuxin; Ma, Lian; Sun, Zhipeng; Qian, Jing

    2014-05-01

    Objective : Experimental and clinical findings suggest that the vomer is involved in facial development and might contribute to the short and retrusive maxilla in cleft patients. The aim of this study was to investigate the relationship between vomer development and maxillary growth in unoperated submucous cleft palate (SMCP) patients. Design : Retrospective cohort study. Participants : Thirty unoperated SMCP patients were included. The criteria for clinical diagnosis were: bifid uvula, a translucent zone in the midline of the soft palate, and a touchable "V" notch on the posterior border of the bony palate. There were 19 female and 11 male patients, with an age range from 3 to 25 years. Interventions : All patients were imaged using spiral computed tomography (CT) while in centric occlusion before the surgeries. Main Outcome Measures : Three-dimensional (3D) reconstruction models were created, and dentoalveolar relationships were rated by three experienced doctors according to the GOSLON score principles. The patients then were divided into three groups: 1 - normal occlusion, 2 - edge-to-edge bite, and 3 - crossbite. The vomer-palate fusion rate was calculated on 3D CT images and represented the vomer development. Results : The sagittal extent of the palatal cleft and the malformation of vomer in SMCP were greatly varied. The vomer-palate fusion rate in the crossbite group (occlusal score = 3) was significantly lower than that in the normal occlusion group (P = .027). Conclusions : Our findings suggest that correlation exists between vomer development and sagittal maxillary growth in unoperated SMCP patients.

  11. Comparison of thoracic radiographs and single breath-hold helical CT for detection of pulmonary nodules in dogs with metastatic neoplasia.

    PubMed

    Nemanic, Sarah; London, Cheryl A; Wisner, Erik R

    2006-01-01

    Imaging studies in people indicate that x-ray computed tomography (CT) is a more sensitive technique than thoracic radiography for the detection of pulmonary metastasic neoplasia. Systematic studies comparing CT and thoracic radiographic techniques in veterinary patients have not been performed. The present retrospective study was designed to directly compare the efficacy of these 2 techniques in detecting pulmonary nodules in dogs. Eighteen dogs with histologically confirmed pulmonary metastatic neoplasia had contemporaneous thoracic radiographs and pulmonary CT scans compared. Quantitative analyses included estimation of pulmonary nodule size, number, and lobar distribution on thoracic radiographs and CT images. Only 9% of CT-detected pulmonary nodules were identified on thoracic radiographs (P < .003). The lower size threshold was approximately 1 mm to detect pulmonary nodules on CT images and 7-9 mm to reliably detect nodules on radiographs (P < .0001). Additionally, pulmonary nodules were detected in a significantly greater number of lung lobes using CT as compared with thoracic radiographs (P < .0001). These data indicate that CT is significantly more sensitive than thoracic radiography for detecting soft-tissue nodules in dogs. As such, thoracic CT should be considered in any patient with neoplasia that has potential for pulmonary metastasis to more reliably stage the disease, particularly when accurate characterization of the extent and distribution of pulmonary metastatic disease affects therapeutic planning.

  12. Helical (spiral) CT in the evaluation of emergent thoracic aortic syndromes. Traumatic aortic rupture, aortic aneurysm, aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer.

    PubMed

    Ledbetter, S; Stuk, J L; Kaufman, J A

    1999-05-01

    For the near future, CT will play the critical and dominant role in the evaluation of patients presenting with emergent aortic syndromes. Its convenience, accuracy, and utility in the rapid evaluation of not just the aorta, but the entire thorax, make it ideally suited for use in emergency settings. Further benefits are likely to be realized in speed and resolution with multislice CT, although it is as yet not widely available.

  13. Detection of hepatocellular carcinoma by Gd-EOB-DTPA-enhanced liver MRI: comparison with triple phase 64 detector row helical CT.

    PubMed

    Akai, Hiroyuki; Kiryu, Shigeru; Matsuda, Izuru; Satou, Jirou; Takao, Hidemasa; Tajima, Taku; Watanabe, Yasushi; Imamura, Hiroshi; Kokudo, Norihiro; Akahane, Masaaki; Ohtomo, Kuni

    2011-11-01

    To compare the diagnostic performance of Gd-EOB-DTPA-enhanced MRI with that of triple phase 64-MDCT in the detection of hepatocellular carcinoma (HCC). Thirty-four patients with 52 surgically proven lesions underwent Gd-EOB-DTPA-enhanced MRI and triple phase 64-MDCT. Two observers independently evaluated MR and CT imaging on a lesion-by-lesion basis. Sensitivity, positive and negative predictive values and reproducibility were evaluated. The diagnostic accuracy of each modality was assessed with alternative-free response receiver operating characteristic (ROC) analysis. Both observers showed higher sensitivity in detecting lesions with MRI compared to CT, however, only the difference between the two imaging techniques for observer 2 was significant (P=0.034). For lesions 1cm or smaller, MRI and CT showed equal sensitivity (both 62.5%) with one observer, and MRI proved superior to CT with the other observer (MRI 75% vs. CT 56.3%), but the latter difference was not significant (P=0.083). The difference in positive and negative predictive value between the two imaging techniques for each observer was not significant (P>0.05). The areas under the ROC curve for each observer were 0.843 and 0.861 for MRI vs. 0.800 and 0.833 for CT and the differences were not significant. Reproducibility was higher using MRI for both observers, but the result was not significant (MRI 32/33 vs. CT 29/33, P=0.083). Gd-EOB-DTPA-enhanced MRI tended to show higher diagnostic accuracy, sensitivity and reproducibility compared to triple phase 64-MDCT in the detection of hepatocellular carcinoma, however statistical significance was not achieved. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Cleft Lip and Palate

    MedlinePlus

    ... and Palate? What Do Doctors Do? en español Labio leporino y paladar hendido When Karly talks to her friends, most of them don't know it took years of hard work for her to develop her speech skills. Karly was born with a condition called cleft lip and palate. As a child, she had several ...

  15. Shifted helical computed tomography to optimize cardiac positron emission tomography-computed tomography coregistration: quantitative improvement and limitations.

    PubMed

    Johnson, Nils P; Pan, Tinsu; Gould, K Lance

    2010-10-01

    Positron emission tomography-computed tomography (PET-CT) uses CT attenuation correction but suffers from misregistration artifacts. However, the quantitative accuracy of helical versus cine CT in the same patient after optimized coregistration by shifting both CT data as needed for each patient is unknown. We studied 293 patients undergoing cardiac perfusion PET-CT using helical CT attenuation correction for comparison to cine CT. Objective, quantitative criteria identified perfusion abnormalities that were associated visually with PET-CT misregistration. Custom software shifted CT data to optimize coregistration with quantitative artifact improvement. The majority (58.1%) of cases with both helical and shifted helical CT data (n  = 93) had artifacts that improved or resolved by software shifting helical CT data. Translation of shifted helical CT was greatest in the x-direction (8.8 ± 3.3 mm) and less in the y- and z-directions (approximately 3.5 mm). The magnitude of differences in quantitative end points was greatest for helical (p  =  .0001, n  =  177 studies), less for shifted helical but significant (p  =  .0001, n  =  93 studies), and least for cine (not significant, n  =  161 studies) CT compared to optimal attenuation correction for each patient. Frequent artifacts owing to attenuation-emission misregistration are substantially corrected by software shifting helical CT scans to achieve proper coregistration that, however, remains on average significantly inferior to cine CT attenuation quantitatively.

  16. Pediatric Palatal Fibroma

    PubMed Central

    Khan, Tayyeb S; Ajaz, Tarannum; Agarwal, Mamta

    2017-01-01

    Fibroma is one of the most common soft tissue benign tumors of the oral cavity. These masses represent hyperplasias instead of true neoplasm, which develop due to irritation to the mucosal tissue resulting in proliferation of the cells. Although so common in the oral cavity, its occurrence on the palate is rare, mainly due to fewer chances of trauma. Here, we report a case of palatal fibroma in a child diagnosed on the basis of clinical, radiological, and histological features. The case represents an extremely rare occurrence as unusual trauma due to thumb sucking seemed to be the only apparent traumatic factor in the palatal region. How to cite this article Mishra R, Khan TS, Ajaz T, Agarwal M. Pediatric Palatal Fibroma. Int J Clin Pediatr Dent 2017; 10(1):96-98. PMID:28377663

  17. Diagnosis of acute flank pain caused by ureteral stones: value of combined direct and indirect signs on IVU and unenhanced helical CT.

    PubMed

    Wang, Li-Jen; Ng, Chip-Jin; Chen, Jih-Chang; Chiu, Te-Fa; Wong, Yon-Cheong

    2004-09-01

    The aim of this study was to assess the usefulness of combined direct and indirect signs on intravenous urography (IVU) and unenhanced helical computed tomography (UHCT) for the diagnosis of ureteral stones in emergency patients with acute flank pain. During an 8-month period, 82 emergency patients with acute flank pain undergoing IVU and UHCT with sufficient clinical follow-up formed the study group. The presence or absence of direct sign (visualization of ureteral stones) and indirect signs on IVU and UHCT was recorded. The diagnostic accuracy of each direct/indirect sign and their combination for the diagnosis of ureteral stones on IVU and UHCT were analyzed and compared. Of the 82 patients, 66 had ureteral stones, four had passed urinary stones prior to imaging and 12 had other diseases. The diagnostic accuracies of direct signs on IVU and UHCT for the diagnosis of ureteral stones were 79.3 and 98.8%, respectively, which was more accurate than that of any single indirect sign on IVU and UHCT. However, the diagnostic accuracy of ureteral stones by IVU increased to 90.2% when using diagnostic criteria requiring the presence of a direct sign or at least three indirect signs, and by UHCT, it increased to 100% when using diagnostic criteria requiring the presence of a direct sign with at least one indirect sign. Therefore, for emergency patients with acute flank pain, the use of the above combinations of direct/indirect signs is useful as the diagnostic criterion for ureteral stones.

  18. Transcatheter Arterial Embolization Therapy for a Hypoplastic Pelvic Kidney with a Single Vaginal Ectopic Ureter to Control Incontinence: The Usefulness of Three-Dimensional CT Angiography Using Multidetector-Row Helical CT

    SciTech Connect

    Kudoh, Kouichi Kadota, Masataka; Nakayama, Yoshiharu; Imuta, Masanori; Yasuda, Tsuyoshi; Yamashita, Yasuyuki; Inadome, Akito; Yoshida, Masaki; Ueda, Shouichi

    2003-09-15

    A girl with continuous urinary incontinence was successfully treated by angiographic embolization of a hypoplastic pelvic kidney with a single unilateral vaginal ectopic opening of the ureter. For this intervention, CT angiography was useful for detecting the corresponding renal artery of the hypoplastic kidney.

  19. Cleft palate cells can regenerate a palatal mucosa in vitro.

    PubMed

    Liu, J; Lamme, E N; Steegers-Theunissen, R P M; Krapels, I P C; Bian, Z; Marres, H; Spauwen, P H M; Kuijpers-Jagtman, A M; Von den Hoff, J W

    2008-08-01

    Cleft palate repair leaves full-thickness mucosal defects on the palate. Healing might be improved by implantation of a mucosal substitute. However, the genetic and phenotypic deviations of cleft palate cells may hamper tissue engineering. The aim of this study was to construct mucosal substitutes from cleft palate cells, and to compare these with substitutes from normal palatal cells, and with native palatal mucosa. Biopsies from the palatal mucosa of eight children with cleft palate and eight age-matched control individuals were taken. Three biopsies of both groups were processed for (immuno)histochemistry; 5 were used to culture mucosal substitutes. Histology showed that the substitutes from cleft-palate and non-cleft-palate cells were comparable, but the number of cell layers was less than in native palatal mucosa. All epithelial layers in native palatal mucosa and mucosal substitutes expressed the cytokeratins 5, 10, and 16, and the proliferation marker Ki67. Heparan sulphate and decorin were present in the basal membrane and the underlying connective tissue, respectively. We conclude that mucosal cells from children with cleft palate can regenerate an oral mucosa in vitro.

  20. Ectopic parathyroid adenoma in the soft palate: a case report.

    PubMed

    Chang, Brent A; Sharma, Anil; Anderson, Donald W

    2016-10-18

    Ectopic parathyroid adenomas can occur in numerous anatomic locations. While ectopic parathyroid adenomas can rarely occur in the pharyngeal region, this has not previously been described in the soft palate. We report the first case of ectopic parathyroid adenoma within the soft palate. A 59 year old woman presented with hyperparathyroidism. She remained persistently hyperparathyroid after initial parathyroidectomy. Repeat exploration for a lesion suspicious on PET-CT for an ectopic parathyroid adenoma in the parapharyngeal region was unsuccessful in treating the hyperparathyroidism. An ectopic adenoma in the soft palate was eventually discovered. Removal through a transoral approach was successful in treating the hyperparathyroidism. Ectopic parathyroid adenomas can occur in various anatomical locations that may be missed even with the use of the various imaging modalities. The soft palate should be added to the list of possible ectopic locations high in the neck.

  1. TGFβ regulates epithelial-mesenchymal interactions through WNT signaling activity to control muscle development in the soft palate

    PubMed Central

    Iwata, Jun-ichi; Suzuki, Akiko; Yokota, Toshiaki; Ho, Thach-Vu; Pelikan, Richard; Urata, Mark; Sanchez-Lara, Pedro A.; Chai, Yang

    2014-01-01

    Clefting of the soft palate occurs as a congenital defect in humans and adversely affects the physiological function of the palate. However, the molecular and cellular mechanism of clefting of the soft palate remains unclear because few animal models exhibit an isolated cleft in the soft palate. Using three-dimensional microCT images and histological reconstruction, we found that loss of TGFβ signaling in the palatal epithelium led to soft palate muscle defects in Tgfbr2fl/fl;K14-Cre mice. Specifically, muscle mass was decreased in the soft palates of Tgfbr2 mutant mice, following defects in cell proliferation and differentiation. Gene expression of Dickkopf (Dkk1 and Dkk4), negative regulators of WNT-β-catenin signaling, is upregulated in the soft palate of Tgfbr2fl/fl;K14-Cre mice, and WNT-β-catenin signaling is disrupted in the palatal mesenchyme. Importantly, blocking the function of DKK1 and DKK4 rescued the cell proliferation and differentiation defects in the soft palate of Tgfbr2fl/fl;K14-Cre mice. Thus, our findings indicate that loss of TGFβ signaling in epithelial cells compromises activation of WNT signaling and proper muscle development in the soft palate through tissue-tissue interactions, resulting in a cleft soft palate. This information has important implications for prevention and non-surgical correction of cleft soft palate. PMID:24496627

  2. [Minimum intensity projection image and curved reformation image of the main pancreatic duct obtained by helical CT in patients with main pancreatic duct dilation].

    PubMed

    Takeshita, K; Furui, S; Yamauchi, T; Harasawa, A; Kohtake, H; Sasaki, Y; Suzuki, S; Tanaka, H; Takeshita, T

    1999-03-01

    Contrast enhanced CT was performed in seven patients with pancreatic disease (chronic pancreatitis, n = 3; pancreatic head cancer, n = 2; mucin-producing pancreatic tumor, n = 2) who showed dilation of the main pancreatic duct (MPD) Minimum intensity projection (Min-IP) images of the pancreas were obtained using multi-projection volume reconstruction (MPVR) software by selecting an oblique slab that contained the entire MPD. Curved reformation (CR) images were obtained using multiplanar reformation (MPR) software by tracing the MPD on the Min-IP image. Both Min-IP images and CR images clearly showed the dilated main pancreatic duct in all seven patients. In three of the seven, obstruction of the MPD in the pancreatic head and the cause of obstruction (tumor mass, n = 2; caliculus, n = 1) were also clearly seen. Min-IP and CR images seem to be useful for the diagnosis of pancreatic diseases.

  3. Cleft Lip and Palate Surgery

    MedlinePlus

    ... The experts in face, mouth and jaw surgery. Cleft Lip / Palate and Craniofacial Surgery This type of surgery is ... the carefully orchestrated, multiple-stage correctional program for cleft lip and palate patients. The goal is to help restore the ...

  4. Helical localized wave solutions of the scalar wave equation.

    PubMed

    Overfelt, P L

    2001-08-01

    A right-handed helical nonorthogonal coordinate system is used to determine helical localized wave solutions of the homogeneous scalar wave equation. Introducing the characteristic variables in the helical system, i.e., u = zeta - ct and v = zeta + ct, where zeta is the coordinate along the helical axis, we can use the bidirectional traveling plane wave representation and obtain sets of elementary bidirectional helical solutions to the wave equation. Not only are these sets bidirectional, i.e., based on a product of plane waves, but they may also be broken up into right-handed and left-handed solutions. The elementary helical solutions may in turn be used to create general superpositions, both Fourier and bidirectional, from which new solutions to the wave equation may be synthesized. These new solutions, based on the helical bidirectional superposition, are members of the class of localized waves. Examples of these new solutions are a helical fundamental Gaussian focus wave mode, a helical Bessel-Gauss pulse, and a helical acoustic directed energy pulse train. Some of these solutions have the interesting feature that their shape and localization properties depend not only on the wave number governing propagation along the longitudinal axis but also on the normalized helical pitch.

  5. Human palatal and tuberosity mucosa as donor sites for ridge augmentation.

    PubMed

    Dellavia, Claudia; Ricci, Giano; Pettinari, Letizia; Allievi, Cristina; Grizzi, Fabio; Gagliano, Nicoletta

    2014-01-01

    Since different clinical outcomes of periodontal bilaminar surgeries using the palate or the maxillary tuberosity as connective tissue (CT) donor sites have been observed, tissues grafted with CT from the palate or the tuberosity 1 year after surgical procedures for ridge augmentation were compared with nongrafted tissues by using morphologic and molecular methods. Collagen content and matrix metalloproteinases 1 and 2 expression were similar in tissues and cultured fibroblasts from the palate and tuberosity, although with interindividual differences. In contrast, differences in collagen cross-linking and maturation in the tuberosity fibroblasts were observed, suggesting a possible role in determining hyperplastic responses in some patients.

  6. Rigid-fixation palatal appliances.

    PubMed

    Staggers, J

    1996-09-01

    Palatal appliances can offer an alternative to the traditional treatment approach of cleft lip and palate. The goal of these appliances is to position the maxillary segments more ideally and then maintain their position while allowing growth to occur. Use of palatal appliances can minimize the iatrogenic growth restriction usually associated with cleft palate repair. This article presents the findings of clinical treatment at the Medical College of Georgia.

  7. Cleft Palate; A Multidiscipline Approach.

    ERIC Educational Resources Information Center

    Stark, Richard B., Ed.

    Nineteen articles present a multidisciplinary approach to the management of facial clefts. The following subjects are discussed: the history of cleft lip and cleft palate surgery; cogenital defects; classification; the operation of a cleft palate clinic; physical examination of newborns with cleft lip and/or palate; nursing care; anesthesia;…

  8. Cleft Lip and Cleft Palate

    MedlinePlus

    ... side. There are three primary types of clefts: • Cleft lip/palate refers to the condition when both the palate ... one in 1,000 babies are born with cleft lip/palate. About 50 percent of all clefts More common ...

  9. Cleft Palate; A Multidiscipline Approach.

    ERIC Educational Resources Information Center

    Stark, Richard B., Ed.

    Nineteen articles present a multidisciplinary approach to the management of facial clefts. The following subjects are discussed: the history of cleft lip and cleft palate surgery; cogenital defects; classification; the operation of a cleft palate clinic; physical examination of newborns with cleft lip and/or palate; nursing care; anesthesia;…

  10. Cleft lip and palate.

    PubMed

    Crockett, David J; Goudy, Steven L

    2014-11-01

    Cleft lip with or without cleft palate is the most common congenital malformation of the head and neck. Orofacial clefting could significantly affect the quality of life of the child and requires multiple steps of care to obtain an optimal outcome. Each patient should be evaluated for congenital anomalies, developmental delay, neurologic disorders, and psychosocial concerns. A multidisciplinary team is necessary to ensure that every aspect of the child's care is appropriately treated and coordination between providers is achieved. This article discusses the assessment and treatment recommendations for children born with cleft lip and/or cleft palate. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Ephrin regulation of palate development

    PubMed Central

    Benson, M. Douglas; Serrano, Maria J.

    2012-01-01

    Studies of palate development are motivated by the all too common incidence of cleft palate, a birth defect that imposes a tremendous health burden and can leave lasting disfigurement. Although, mechanistic studies of palate growth and fusion have focused on growth factors such as Transforming Growth Factor ß-3 (Tgfß3), recent studies have revealed that the ephrin family of membrane bound ligands and their receptors, the Ephs, play central roles in palatal morphogenesis, growth, and fusion. In this mini-review, we will discuss the recent findings by our group and others on the functions of ephrins in palatal development. PMID:23055980

  12. Accommodating Picky Palates

    ERIC Educational Resources Information Center

    Lum, Lydia

    2007-01-01

    Healthy gourmet offerings are fast becoming the norm at college dining halls around the country. At a time when the children of Baby Boomers are hitting higher education in record numbers, college officials have scrambled to accommodate their picky palates and their insistence for healthier meals than were served to past generations. At the same…

  13. Epileptic palatal myoclonus

    SciTech Connect

    Tatum, W.O.; Sperling, M.R.; Jacobstein, J.G. )

    1991-08-01

    Palatal myoclonus (PM) is usually caused by lesions of the brainstem. The authors report a case of PM of focal cortical origin in a patient with epilepsia partialis continua. The PM sometimes occurred in isolation, and at other times was accompanied by unilateral face, neck, and arm twitching. This was documented by both EEG and SPECT.

  14. Cleft Lip and Palate

    MedlinePlus

    ... all the way to the back of your mouth. What's a Cleft Lip or Cleft Palate? The word cleft means a gap or split between two things. A cleft lip is a split in the upper lip. This can happen on one or ... a split in the roof of the mouth. This leaves a hole between the nose and ...

  15. Accommodating Picky Palates

    ERIC Educational Resources Information Center

    Lum, Lydia

    2007-01-01

    Healthy gourmet offerings are fast becoming the norm at college dining halls around the country. At a time when the children of Baby Boomers are hitting higher education in record numbers, college officials have scrambled to accommodate their picky palates and their insistence for healthier meals than were served to past generations. At the same…

  16. Helicity content and tokamak applications of helicity

    SciTech Connect

    Boozer, A.H.

    1986-05-01

    Magnetic helicity is approximately conserved by the turbulence associated with resistive instabilities of plasmas. To generalize the application of the concept of helicity, the helicity content of an arbitrary bounded region of space will be defined. The definition has the virtues that both the helicity content and its time derivative have simple expressions in terms of the poloidal and toroidal magnetic fluxes, the average toroidal loop voltage and the electric potential on the bounding surface, and the volume integral of E-B. The application of the helicity concept to tokamak plasmas is illustrated by a discussion of so-called MHD current drive, an example of a stable tokamak q profile with q less than one in the center, and a discussion of the possibility of a natural steady-state tokamak due to the bootstrap current coupling to tearing instabilities.

  17. Schwannoma of the hard palate

    PubMed Central

    Sahoo, Pradyumna Kumar; Mandal, Palash Kumar; Ghosh, Saradindu

    2014-01-01

    Schwannomas are benign encapsulated perineural tumors. The head and neck region is the most common site. Intraoral origin is seen in only 1% of cases, tongue being the most common site; its location in the palate is rare. We report a case of hard-palate schwannoma with bony erosion which was immunohistochemically confirmed. The tumor was excised completely intraorally. After two months of follow-up, the defect was found to be completely covered with palatal mucosa. PMID:25298716

  18. Pleomorphic adenoma of the palate

    PubMed Central

    Sharma, Yogesh; Maria, Anisha; Chhabria, Amit

    2011-01-01

    Pleomorphic adenoma (PA) is the most common salivary gland tumor, accounting for about 40–70% of all major and minor salivary gland tumors. The commonest sites for intraoral PA are palate, buccal mucosa and lips. Palatal PA presents clinically as a painless, slow-growing mass found on posterior lateral aspect. The aim of this article is to present a case of palatal PA, which was treated successfully by surgical excision. PMID:22639506

  19. Bmpr1a signaling plays critical roles in palatal shelf growth and palatal bone formation

    PubMed Central

    Baek, Jin-A; Lan, Yu; Liu, Han; Maltby, Kathleen M.; Mishina, Yuji; Jiang, Rulang

    2011-01-01

    Cleft palate, including submucous cleft palate, is among the most common birth defects in humans. While overt cleft palate results from defects in growth or fusion of the developing palatal shelves, submucous cleft palate is characterized by defects in palatal bones. In this report, we show that the Bmpr1a gene, encoding a type I receptor for bone morphogenetic proteins (Bmp), is preferentially expressed in the primary palate and anterior secondary palate during palatal outgrowth. Following palatal fusion, Bmpr1a mRNA expression was upregulated in the condensed mesenchyme progenitors of palatal bone. Tissue-specific inactivation of Bmpr1a in the developing palatal mesenchyme in mice caused reduced cell proliferation in the primary and anterior secondary palate, resulting in partial cleft of the anterior palate at birth. Expression of Msx1 and Fgf10 was downregulated in the anterior palate mesenchyme and expression of Shh was downregulated in the anterior palatal epithelium in the Bmpr1a conditional mutant embryos, indicating that Bmp signaling regulates mesenchymal-epithelial interactions during palatal outgrowth. In addition, formation of the palatal processes of the maxilla was blocked while formation of the palatal processes of the palatine was significantly delayed, resulting in submucous cleft of the hard palate in the mutant mice. Our data indicate that Bmp signaling plays critical roles in the regulation of palatal mesenchyme condensation and osteoblast differentiation during palatal bone formation. PMID:21185278

  20. Initial experience in treating lung cancer with helical tomotherapy

    PubMed Central

    Yartsev, S; Dar, AR; Woodford, C; Wong, E; Bauman, G; Van Dyk, J

    2007-01-01

    Helical tomotherapy is a new form of image-guided radiation therapy that combines features of a linear accelerator and a helical computed tomography (CT) scanner. Megavoltage CT (MVCT) data allow the verification and correction of patient setup on the couch by comparison and image registration with the kilovoltage CT multi-slice images used for treatment planning. An 84-year-old male patient with Stage III bulky non-small cell lung cancer was treated on a Hi-ART II tomotherapy unit. Daily MVCT imaging was useful for setup corrections and signaled the need to adapt the delivery plan when the patient’s anatomy changed significantly. PMID:21614260

  1. Congenital Palatal Fistula Associated with Submucous Cleft Palate

    PubMed Central

    Eshete, Mekonen; Camison, Liliana; Abate, Fikre; Hailu, Taye; Demissie, Yohannes; Mohammed, Ibrahim; Butali, Azeez; Losken, H. Wolfgang

    2016-01-01

    Background: Although cleft lip and cleft palate are among the most common congenital malformations, the presence of an isolated congenital palatal fistula along with a submucous cleft is very rare. This appears as an oval-shaped, full-thickness fenestration in the palatal midline that does not fully extend anteriorly or posteriorly, accompanied by the findings of a submucous cleft. Because of the uncommon nature of this entity, there is controversy about its etiology, diagnosis, and management. Methods: Two cases of children with congenital palatal fistulae and a submucous cleft palate are presented who were treated in different settings by different surgeons. Cases are discussed along with a thorough review of the available literature. Results: Patient 1 presented at 4 years of age with “a hole in the palate” since birth and abnormal speech. His palatal fistula and submucous cleft were repaired with a modified von Langenbeck technique in Ethiopia. At a 2-year follow-up, the palate remained closed, but hypernasal speech persisted. Patient 2 was a 1-year-old presenting with failure to thrive and nasal regurgitation, who underwent a Furlow palatoplasty in the United States with good immediate results. She was unfortunately lost to follow-up. Conclusions: A congenital fenestration of the palate is rare. Reports reveal suboptimal speech at follow-up, despite various types of repair, especially when combined with a submucous cleft. Available literature suggests that repair should not focus on fistula closure only but instead on providing adequate palate length to provide good velopharyngeal function, as in any cleft palate repair. PMID:27014542

  2. Shearing wind helicity and thermal wind helicity

    NASA Astrophysics Data System (ADS)

    Han, Y.; Wu, R. S.; Fang, J.

    2006-07-01

    Helicity is defined as H = V . omega, where V and omega are the velocity and vorticity vectors, respectively. Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. However, the direct relationship of the helicity to the evolution of the weather system is not quite clear. In this paper, the concept of helicity is generalized as shearing wind helicity (SWH). Dynamically, it is found that the average SWH is directly related to the increase of the average cyclonic rotation of the weather system. Physically, it is also pointed out that the SWH, as a matter of fact, is the sum of the torsion terms and the divergence term in the vorticity equation. Thermal wind helicity (TWH), as a derivative of SWH, is also discussed here because it links the temperature field and the vertical wind field. These two quantities may be effective for diagnosing a weather system. This paper applies these two quantities in cylindrical coordinates to study the development of Hurricane Andrew to validate their practical use. Through analyzing the hurricane, it is found that TWH can well describe the characteristics of the hurricane such as the strong convection and release of latent heat. SWH is not only a good quantity for diagnosing the weather system, but also an effective one for diagnosing the development of the hurricane.

  3. From shape to cells: mouse models reveal mechanisms altering palate development in Apert syndrome.

    PubMed

    Martínez-Abadías, Neus; Holmes, Greg; Pankratz, Talia; Wang, Yingli; Zhou, Xueyan; Jabs, Ethylin Wang; Richtsmeier, Joan T

    2013-05-01

    Apert syndrome is a congenital disorder characterized by severe skull malformations and caused by one of two missense mutations, S252W and P253R, on fibroblast growth factor receptor 2 (FGFR2). The molecular bases underlying differential Apert syndrome phenotypes are still poorly understood and it is unclear why cleft palate is more frequent in patients carrying the S252W mutation. Taking advantage of Apert syndrome mouse models, we performed a novel combination of morphometric, histological and immunohistochemical analyses to precisely quantify distinct palatal phenotypes in Fgfr2(+/S252W) and Fgfr2(+/P253R) mice. We localized regions of differentially altered FGF signaling and assessed local cell patterns to establish a baseline for understanding the differential effects of these two Fgfr2 mutations. Palatal suture scoring and comparative 3D shape analysis from high resolution μCT images of 120 newborn mouse skulls showed that Fgfr2(+/S252W) mice display relatively more severe palate dysmorphologies, with contracted and more separated palatal shelves, a greater tendency to fuse the maxillary-palatine sutures and aberrant development of the inter-premaxillary suture. These palatal defects are associated with suture-specific patterns of abnormal cellular proliferation, differentiation and apoptosis. The posterior region of the developing palate emerges as a potential target for therapeutic strategies in clinical management of cleft palate in Apert syndrome patients.

  4. From shape to cells: mouse models reveal mechanisms altering palate development in Apert syndrome

    PubMed Central

    Martínez-Abadías, Neus; Holmes, Greg; Pankratz, Talia; Wang, Yingli; Zhou, Xueyan; Jabs, Ethylin Wang; Richtsmeier, Joan T.

    2013-01-01

    SUMMARY Apert syndrome is a congenital disorder characterized by severe skull malformations and caused by one of two missense mutations, S252W and P253R, on fibroblast growth factor receptor 2 (FGFR2). The molecular bases underlying differential Apert syndrome phenotypes are still poorly understood and it is unclear why cleft palate is more frequent in patients carrying the S252W mutation. Taking advantage of Apert syndrome mouse models, we performed a novel combination of morphometric, histological and immunohistochemical analyses to precisely quantify distinct palatal phenotypes in Fgfr2+/S252W and Fgfr2+/P253R mice. We localized regions of differentially altered FGF signaling and assessed local cell patterns to establish a baseline for understanding the differential effects of these two Fgfr2 mutations. Palatal suture scoring and comparative 3D shape analysis from high resolution μCT images of 120 newborn mouse skulls showed that Fgfr2+/S252W mice display relatively more severe palate dysmorphologies, with contracted and more separated palatal shelves, a greater tendency to fuse the maxillary-palatine sutures and aberrant development of the inter-premaxillary suture. These palatal defects are associated with suture-specific patterns of abnormal cellular proliferation, differentiation and apoptosis. The posterior region of the developing palate emerges as a potential target for therapeutic strategies in clinical management of cleft palate in Apert syndrome patients. PMID:23519026

  5. Radiology of Cleft Lip and Palate: Imaging for the Prenatal Period and throughout Life.

    PubMed

    Abramson, Zachary R; Peacock, Zachary S; Cohen, Harris L; Choudhri, Asim F

    2015-01-01

    Recent advances in prenatal imaging have made possible the in utero diagnosis of cleft lip and palate and associated deformities. Postnatal diagnosis of cleft lip is made clinically, but imaging still plays a role in detection of associated abnormalities, surgical treatment planning, and screening for or surveillance of secondary deformities. This article describes the clinical entities of cleft lip with or without cleft palate (CLP) and isolated cleft palate and documents their prenatal and postnatal appearances at radiography, ultrasonography (US), magnetic resonance (MR) imaging, and computed tomography (CT). Imaging protocols and findings for prenatal screening, detection of associated anomalies, and evaluation of secondary deformities throughout life are described and illustrated. CLP and isolated cleft palate are distinct entities with shared radiologic appearances. Prenatal US and MR imaging can depict clefting of the lip or palate and associated anomalies. While two- and three-dimensional US often can depict cleft lip, visualization of cleft palate is more difficult, and repeat US or fetal MR imaging should be performed if cleft palate is suspected. Postnatal imaging can assist in identifying associated abnormalities and dentofacial deformities. Dentofacial sequelae of cleft lip and palate include missing and supernumerary teeth, oronasal fistulas, velopharyngeal insufficiency, hearing loss, maxillary growth restriction, and airway abnormalities. Secondary deformities can often be found incidentally at imaging performed for other purposes, but detection is necessary because they may have considerable implications for the patient.

  6. Palatalization in Romanian: Experimental and Theoretical Approaches

    ERIC Educational Resources Information Center

    Spinu, Laura

    2010-01-01

    Within the larger context of the Romance languages, Romanian stands alone in exhibiting a surface contrast between plain and palatalized consonants (that is, consonants with a secondary palatal articulation). While the properties of secondary palatalization are well known for language families in which the set of palatalized consonants is…

  7. Craniomaxillofacial abnormalities in dogs with congenital palatal defects: computed tomographic findings.

    PubMed

    Nemec, Ana; Daniaux, Lise; Johnson, Eric; Peralta, Santiago; Verstraete, Frank J M

    2015-05-01

    To evaluate craniomaxillofacial abnormalities in dogs with congenital palatal defects. Retrospective computed tomography (CT) study. Dogs with congenital palatal defects (n = 9). Medical records and CT reports (1995-2012) were searched for dogs with a diagnosis of cleft palate that had a CT study. Data retrieved were: breed, age, sex, weight, physical examination, and laboratory findings, number of previous palate surgeries, and oral/dental examination findings with the diagnosis of the cleft for each dog. CT studies of the head were reviewed on a structure-by-structure basis. Tympanic bullae were most commonly found to be abnormal (8 dogs), followed by nasal turbinates (6), nasal septum, vomer, cribriform plate (4), frontal sinuses, and lateral ventricles (3). Other abnormalities were related to occlusion, teeth, incisive bones, maxillary bones, mandibles, hyoid apparatus, cranial bones, and nasopharynx. The soft tissue defect of the cleft was always smaller than the bony defect. Craniomaxillofacial abnormalities in dogs with congenital palatal defects are common and some of these may negatively affect the quality of life. Importantly for surgical planning, the soft tissue component of the cleft may underestimate the extent of the bony defect, especially in failed repairs. © Copyright 2014 by The American College of Veterinary Surgeons.

  8. Cleft palate in Pfeiffer syndrome.

    PubMed

    Stoler, Joan M; Rosen, Heather; Desai, Urmen; Mulliken, John B; Meara, John G; Rogers, Gary F

    2009-09-01

    The frequency of associated cleft palate is known to be high in some fibroblast growth factor receptor 2 (FGFR2)-mediated craniosynostosis syndromes, such as Apert syndrome. However, there is little information on the frequency of palatal clefts in the FGFR2-mediated disorder, that is, Pfeiffer syndrome. The purpose of this study was to determine the frequency of palatal clefts in patients with Pfeiffer syndrome. The records of patients with Pfeiffer syndrome managed in our craniofacial unit were reviewed. Only patients with a confirmed diagnosis of Pfeiffer syndrome were included. Diagnostic criteria were as follows: characteristic mutations in FGFR1 or FGFR2 or, in the absence of genetic testing, clinical findings consistent with Pfeiffer syndrome as determined by a clinical geneticist or our most experienced surgeon (J.B.M.). Only 2 clefts were noted in 25 patients (8%), including 1 with a submucous cleft and 1 with an overt palatal cleft. Many patients (87%) were described as having a high-arched and narrow palate, and 1 had a low, broad palate. Nine patients were noted to have choanal atresia or stenosis. Clefting of the palate does occur in Pfeiffer syndrome but at a low frequency.

  9. Molecular basis of cleft palates in mice

    PubMed Central

    Funato, Noriko; Nakamura, Masataka; Yanagisawa, Hiromi

    2015-01-01

    Cleft palate, including complete or incomplete cleft palates, soft palate clefts, and submucosal cleft palates, is the most frequent congenital craniofacial anomaly in humans. Multifactorial conditions, including genetic and environmental factors, induce the formation of cleft palates. The process of palatogenesis is temporospatially regulated by transcription factors, growth factors, extracellular matrix proteins, and membranous molecules; a single ablation of these molecules can result in a cleft palate in vivo. Studies on knockout mice were reviewed in order to identify genetic errors that lead to cleft palates. In this review, we systematically describe these mutant mice and discuss the molecular mechanisms of palatogenesis. PMID:26322171

  10. Emerging double helical nanostructures

    NASA Astrophysics Data System (ADS)

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-07-01

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on `bottom-up' and `top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  11. A Helical Stairway Project

    ERIC Educational Resources Information Center

    Farmer, Tom

    2008-01-01

    We answer a geometric question that was raised by the carpenter in charge of erecting helical stairs in a 10-story hospital. The explanation involves the equations of lines, planes, and helices in three-dimensional space. A brief version of the question is this: If A and B are points on a cylinder and the line segment AB is projected radially onto…

  12. Emerging double helical nanostructures.

    PubMed

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-08-21

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on 'bottom-up' and 'top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  13. Helical computed tomography in differentiating appendicitis and acute gynecologic conditions.

    PubMed

    Rao, P M; Feltmate, C M; Rhea, J T; Schulick, A H; Novelline, R A

    1999-03-01

    To determine the accuracy and effect of helical computed tomography (CT) in women clinically suspected of having either appendicitis or an acute gynecologic condition. One hundred consecutive nonpregnant women suspected of having appendicitis or an acute gynecologic condition prospectively had helical CT. Interpretations were correlated with surgical and pathologic findings (41 cases) and clinical follow-up for at least 2 months (59 cases). The accuracy for confirming or excluding both appendicitis and acute gynecologic conditions was determined. The effect on patient care was determined by comparing pre-CT plans with actual treatment. Thirty-two women had appendicitis, 15 had acute gynecologic conditions, 27 had other specific diagnoses, and 26 had nonspecific abdominal pain. For diagnosing appendicitis or acute gynecologic conditions, CT had 100% and 87% sensitivity, 97% and 100% specificity, 94% and 100% positive predictive value, 100% and 98% negative predictive value, and 98% and 98% accuracy, respectively. After CT was done, 36 planned hospital admissions, 25 planned hospital observations, and six planned appendectomies were deferred; six women had alternative surgical procedures on the basis of CT results. One patient had an unnecessary appendectomy on the basis of CT findings. Helical CT is an excellent imaging option for differentiating appendicitis from most acute gynecologic conditions.

  14. Cleft Lip and Cleft Palate

    MedlinePlus

    ... and advocacy priorities National Network of Perinatal Quality Collaboratives Launch Prematurity research centers What is team science? ... how the body develops or how the body works. Cleft lip and cleft palate are common birth ...

  15. Cine CT for Attenuation Correction in Cardiac PET/CT

    PubMed Central

    Alessio, Adam M.; Kohlmyer, Steve; Branch, Kelley; Chen, Grace; Caldwell, James; Kinahan, Paul

    2008-01-01

    In dual-modality PET/CT systems, the CT scan provides the attenuation map for PET attenuation correction. The current clinical practice of obtaining a single helical CT scan provides only a snapshot of the respiratory cycle, whereas PET occurs over multiple respiratory cycles. Misalignment of the attenuation map and emission image because of respiratory motion causes errors in the attenuation correction factors and artifacts in the attenuation-corrected PET image. To rectify this problem, we evaluated the use of cine CT, which acquires multiple low-dose CT images during a respiratory cycle. We evaluated the average and the intensity-maximum image of cine CT for cardiac PET attenuation correction. Methods Cine CT data and cardiac PET data were acquired from a cardiac phantom and from multiple patient studies. The conventional helical CT, cine CT, and PET data of an axially translating phantom were evaluated with and without respiratory motion. For the patient studies, we acquired 2 cine CT studies for each PET acquisition in a rest–stress 13N-ammonia protocol. Three readers visually evaluated the alignment of 74 attenuation image sets versus the corresponding emission image and determined whether the alignment provided acceptable or unacceptable attenuation-corrected PET images. Results In the phantom study, the attenuation correction from helical CT caused a major artifactual defect in the lateral wall on the PET image. The attenuation correction from the average and from the intensity-maximum cine CT images reduced the defect by 20% and 60%, respectively. In the patient studies, 77% of the cases using the average of the cine CT images had acceptable alignment and 88% of the cases using the intensity maximum of the cine CT images had acceptable alignment. Conclusion Cine CT offers an alternative to helical CT for compensating for respiratory motion in the attenuation correction of cardiac PET studies. Phantom studies suggest that the average and the intensity

  16. Space Technology for Palate Surgery

    NASA Technical Reports Server (NTRS)

    1980-01-01

    University of Miami utilized NASA's spacecraft viewing technology to develop the optical profilometer provides more accurate measurements of cleft palate casts than has heretofore been possible, enabling better planning of corrective surgery. Lens like instrument electronically scans a palate cast precisely measuring its irregular contours by detecting minute differences in the intensity of a light beam reflected off the cast. Readings are computer processed and delivered to the surgeon by a teleprinter.

  17. Cleft palate repair and variations

    PubMed Central

    Agrawal, Karoon

    2009-01-01

    Cleft palate affects almost every function of the face except vision. Today a child born with cleft palate with or without cleft lip should not be considered as unfortunate, because surgical repair of cleft palate has reached a highly satisfactory level. However for an average cleft surgeon palatoplasty remains an enigma. The surgery differs from centre to centre and surgeon to surgeon. However there is general agreement that palatoplasty (soft palate at least) should be performed between 6-12 months of age. Basically there are three groups of palatoplasty techniques. One is for hard palate repair, second for soft palate repair and the third based on the surgical schedule. Hard palate repair techniques are Veau-Wardill-Kilner V-Y, von Langenbeck, two-flap, Aleveolar extension palatoplasty, vomer flap, raw area free palatoplasty etc. The soft palate techniques are intravelar veloplasty, double opposing Z-plasty, radical muscle dissection, primary pharyngeal flap etc. And the protocol based techniques are Schweckendiek's, Malek's, whole in one, modified schedule with palatoplasty before lip repair etc. One should also know the effect of each technique on maxillofacial growth and speech. The ideal technique of palatoplasty is the one which gives perfect speech without affecting the maxillofacial growth and hearing. The techniques are still evolving because we are yet to design an ideal one. It is always good to know all the techniques and variations so that one can choose whichever gives the best result in one's hands. A large number of techniques are available in literature, and also every surgeon incorporates his own modification to make it a variation. However there are some basic techniques, which are described in details which are used in various centres. Some of the important variations are also described. PMID:19884664

  18. Molecular Anatomy of Palate Development.

    PubMed

    Potter, Andrew S; Potter, S Steven

    2015-01-01

    The NIH FACEBASE consortium was established in part to create a central resource for craniofacial researchers. One purpose is to provide a molecular anatomy of craniofacial development. To this end we have used a combination of laser capture microdissection and RNA-Seq to define the gene expression programs driving development of the murine palate. We focused on the E14.5 palate, soon after medial fusion of the two palatal shelves. The palate was divided into multiple compartments, including both medial and lateral, as well as oral and nasal, for both the anterior and posterior domains. A total of 25 RNA-Seq datasets were generated. The results provide a comprehensive view of the region specific expression of all transcription factors, growth factors and receptors. Paracrine interactions can be inferred from flanking compartment growth factor/receptor expression patterns. The results are validated primarily through very high concordance with extensive previously published gene expression data for the developing palate. In addition selected immunostain validations were carried out. In conclusion, this report provides an RNA-Seq based atlas of gene expression patterns driving palate development at microanatomic resolution. This FACEBASE resource is designed to promote discovery by the craniofacial research community.

  19. Deformation of the palate in preterm infants

    PubMed Central

    Procter, A.; Lether, D.; Oliver, R.; Cartlidge, P. H.

    1998-01-01

    AIM—To investigate the effect of gestation, postmenstrual age, and orotracheal intubation on palate morphology.
METHODS—A prospective study was made of 76 newborn infants of 25 to 41 weeks' gestation. Palate dimensions were measured on plaster models produced from serial palatal impressions. Palate size relative to that of the mouth was assessed using a ratio of palate depth to palate width (Palatal Index).
RESULTS—Palate depth and width were related to postmenstrual age and gestation. Palatal Index ranged from 0.15 to 0.57, indicating a wide variation in palate shape, but gestation and postmenstrual age had no effect. Prolonged intubation had a small effect, equivalent to an increase in palatal depth of less than 2 mm at 32 weeks' postmenstrual age. The effect was transient.
CONCLUSION—Prolonged orotracheal intubation (>10 days) leads to a small and temporary increase in palatal depth. However, this is unlikely to account for palatal grooving, which is probably caused by an overgrowth of the lateral palatine ridges.

 PMID:9536837

  20. Squeezed helical elastica.

    PubMed

    Bouzar, Lila; Müller, Martin Michael; Gosselin, Pierre; Kulić, Igor M; Mohrbach, Hervé

    2016-11-01

    We theoretically study the conformations of a helical semi-flexible filament confined to a flat surface. This squeezed helix exhibits a variety of unexpected shapes resembling circles, waves or spirals depending on the material parameters. We explore the conformation space in detail and show that the shapes can be understood as the mutual elastic interaction of conformational quasi-particles. Our theoretical results are potentially useful to determine the material parameters of such helical filaments in an experimental setting.

  1. Cleft lip and palate repair - discharge

    MedlinePlus

    ... lip and palate Cleft lip and palate repair Review Date 5/9/2016 Updated by: David A. ... and reconstructive plastic surgery, Palm Beach Gardens, FL. Review provided by VeriMed Healthcare Network. Also reviewed by ...

  2. Factors prognostic for phonetic development after cleft palate repair.

    PubMed

    Lee, Joon Seok; Kim, Jae Bong; Lee, Jeong Woo; Yang, Jung Dug; Chung, Ho Yun; Cho, Byung Chae; Choi, Kang Young

    2015-10-01

    Palatoplasty is aimed to achieve normal speech, improve food intake, and ensure successful maxillary growth. However, the velopharyngeal function is harder to control than other functions. Therefore, many studies on the prognostic factor of velopharyngeal insufficiency have been conducted. This study aimed to evaluate the relationships between speech outcomes and multimodality based on intraoral and preoperative three-dimensional computerized tomographic (CT) findings. Among 73 children with cleft palate who underwent palatoplasty between April 2011 and August 2014 at Kyungpook National University Hospital (KNUH), 27 were retrospectively evaluated. The 27 cases were non-syndromic, for which successful speech evaluation was conducted by a single speech-language pathologist (Table 1). Successful speech evaluation was defined as performing the test three times in 6-month intervals. Three intraoral parameters were measured before and immediately after operation (Fig. 1). On axial- and coronal-view preoperative facial CT, 5 and 2 different parameters were analyzed, respectively (Figs. 2 and 3). Regression analysis (SPSS IBM 22.0) was used in the statistical analysis. Two-flap palatoplasty and Furlow's double opposing Z-plasty were performed in 15 and 12 patients, respectively. The operation was performed 11 months after birth on average. Children with a higher palatal arch and wider maxillary tuberosity distance showed hypernasality (p < 0.05; Table 2). The useful prognostic factors of velopharyngeal function after palatoplasty were palate width and height, rather than initial diagnosis, treatment method, or palate length. Therefore, a more active intervention is needed, such as orthopedic appliance, posterior pharyngeal wall augmentation, or early speech training. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  3. Non-axisymmetric Electrostatic Helicity Injection into the HIST Spherical Torus

    NASA Astrophysics Data System (ADS)

    Nagata, M.; Akamatsu, T.; Kagei, Y.; Fukumoto, N.; Uyama, T.

    2000-10-01

    Studies of helicity injection physics including the magnetohydrodynamic (MHD) dynamo and self-organizing phenomena are very important in the spherical torus (ST) and spheromak research. In the HIST experiment, we have found that the intermittent generation of plasma current on ST by coaxial helicity injection (CHI) is responsible for repetitive plasmoid injection from the coaxial gun. We have verified that helicity balance is satisfied during the axisymmetric plasmoid injection process. In order to investigate furthermore the important role of helicity by varying the topology of the system, i.e. symmetry breaking, we perform non-axisymmetric electrostatic helicity injection experiments on FACT and HIST using Compact Torus (CT) injector. CT injector can inject the spheromak with both particle and helicity into the ST plasma from the outboard side. A long-lived spheromak tends to relax to the m=1 helical state in the entrance/drift tube of the CT injector. If we can maintain the m=1 helical configuration there in a steady state, so helicity is continuously transported from the injector toward the outer edge of ST, resulting in current drive through MHD relaxation. In the FACT-ST experiment, we observed that the toroidal current is amplified during spheromak injection, and also investigated the behavoir of the spheromak injected in the ST plasma.

  4. CLEFT PALATE. FOUNDATIONS OF SPEECH PATHOLOGY SERIES.

    ERIC Educational Resources Information Center

    RUTHERFORD, DAVID; WESTLAKE, HAROLD

    DESIGNED TO PROVIDE AN ESSENTIAL CORE OF INFORMATION, THIS BOOK TREATS NORMAL AND ABNORMAL DEVELOPMENT, STRUCTURE, AND FUNCTION OF THE LIPS AND PALATE AND THEIR RELATIONSHIPS TO CLEFT LIP AND CLEFT PALATE SPEECH. PROBLEMS OF PERSONAL AND SOCIAL ADJUSTMENT, HEARING, AND SPEECH IN CLEFT LIP OR CLEFT PALATE INDIVIDUALS ARE DISCUSSED. NASAL RESONANCE…

  5. CLEFT PALATE. FOUNDATIONS OF SPEECH PATHOLOGY SERIES.

    ERIC Educational Resources Information Center

    RUTHERFORD, DAVID; WESTLAKE, HAROLD

    DESIGNED TO PROVIDE AN ESSENTIAL CORE OF INFORMATION, THIS BOOK TREATS NORMAL AND ABNORMAL DEVELOPMENT, STRUCTURE, AND FUNCTION OF THE LIPS AND PALATE AND THEIR RELATIONSHIPS TO CLEFT LIP AND CLEFT PALATE SPEECH. PROBLEMS OF PERSONAL AND SOCIAL ADJUSTMENT, HEARING, AND SPEECH IN CLEFT LIP OR CLEFT PALATE INDIVIDUALS ARE DISCUSSED. NASAL RESONANCE…

  6. Helical plasma thruster

    SciTech Connect

    Beklemishev, A. D.

    2015-10-15

    A new scheme of plasma thruster is proposed. It is based on axial acceleration of rotating magnetized plasmas in magnetic field with helical corrugation. The idea is that the propellant ionization zone can be placed into the local magnetic well, so that initially the ions are trapped. The E × B rotation is provided by an applied radial electric field that makes the setup similar to a magnetron discharge. Then, from the rotating plasma viewpoint, the magnetic wells of the helically corrugated field look like axially moving mirror traps. Specific shaping of the corrugation can allow continuous acceleration of trapped plasma ions along the magnetic field by diamagnetic forces. The accelerated propellant is expelled through the expanding field of magnetic nozzle. By features of the acceleration principle, the helical plasma thruster may operate at high energy densities but requires a rather high axial magnetic field, which places it in the same class as the VASIMR{sup ®} rocket engine.

  7. Helical screw viscometer

    NASA Astrophysics Data System (ADS)

    Aubert, J. H.; Chapman, R. N.; Kraynik, A. M.

    1983-06-01

    A helical screw viscometer for the measurement of the viscosity of Newtonian and nonNewtonian fluids is comprised of an elongated cylindrical container closed by end caps defining a circular cylindrical cavity within the container, a cylindrical rotor member having a helical screw or ribbon flight carried by the other periphery thereof rotatably carried within the cavity. The fluid to be measured is confined in the cavity filling the space between the rotor and the container wall. The rotor member is supported by axle members journaled in the end caps, one axle extending through one end cap and connectable to a drive source. A pair of longitudinally spaced ports are provided through the wall of the container in communication with the cavity and a differential pressure meter is connected between the ports for measuring the pressure drop caused by the rotation of the helical screw rotor acting on the confined fluid for computing viscosity.

  8. Helical plasma thruster

    NASA Astrophysics Data System (ADS)

    Beklemishev, A. D.

    2015-10-01

    A new scheme of plasma thruster is proposed. It is based on axial acceleration of rotating magnetized plasmas in magnetic field with helical corrugation. The idea is that the propellant ionization zone can be placed into the local magnetic well, so that initially the ions are trapped. The E × B rotation is provided by an applied radial electric field that makes the setup similar to a magnetron discharge. Then, from the rotating plasma viewpoint, the magnetic wells of the helically corrugated field look like axially moving mirror traps. Specific shaping of the corrugation can allow continuous acceleration of trapped plasma ions along the magnetic field by diamagnetic forces. The accelerated propellant is expelled through the expanding field of magnetic nozzle. By features of the acceleration principle, the helical plasma thruster may operate at high energy densities but requires a rather high axial magnetic field, which places it in the same class as the VASIMR® rocket engine.

  9. Mathisson's helical motions demystified

    NASA Astrophysics Data System (ADS)

    Costa, L. Filipe; Natário, José; Zilhão, Miguel

    2012-07-01

    The motion of spinning test particles in general relativity is described by Mathisson-Papapetrou-Dixon equations, which are undetermined up to a spin supplementary condition, the latter being today still an open question. The Mathisson-Pirani (MP) condition is known to lead to rather mysterious helical motions which have been deemed unphysical, and for this reason discarded. We show that these assessments are unfounded and originate from a subtle (but crucial) misconception. We discuss the kinematical explanation of the helical motions, and dynamically interpret them through the concept of hidden momentum, which has an electromagnetic analogue. We also show that, contrary to previous claims, the frequency of the helical motions coincides exactly with the zitterbewegung frequency of the Dirac equation for the electron.

  10. Helical screw viscometer

    DOEpatents

    Aubert, J.H.; Chapman, R.N.; Kraynik, A.M.

    1983-06-30

    A helical screw viscometer for the measurement of the viscosity of Newtonian and non-Newtonian fluids comprising an elongated cylindrical container closed by end caps defining a circular cylindrical cavity within the container, a cylindrical rotor member having a helical screw or ribbon flight carried by the outer periphery thereof rotatably carried within the cavity whereby the fluid to be measured is confined in the cavity filling the space between the rotor and the container wall. The rotor member is supported by axle members journaled in the end caps, one axle extending through one end cap and connectable to a drive source. A pair of longitudinally spaced ports are provided through the wall of the container in communication with the cavity and a differential pressure meter is connected between the ports for measuring the pressure drop caused by the rotation of the helical screw rotor acting on the confined fluid for computing viscosity.

  11. Cleft Lip and Cleft Palate

    MedlinePlus

    ... or cleft palate. A cleft lip is a separation of the two sides of the lip. The separation often includes the bones of the upper jaw ... 5 Comments Miracle Flights Puts Care in the Air 11/20/15 , No Comments Connections to be ...

  12. Orthodontic palatal implants: clinical technique.

    PubMed

    Tinsley, D; O'Dwyer, J J; Benson, P E; Doyle, P T; Sandler, J

    2004-03-01

    The aim of this paper is to familiarize the readers with some of the clinical considerations necessary to ensure successful use of mid-palatal implants. Both surgical and technical aspects will be discussed along with a description of impression techniques used.

  13. Helical-D pinch

    SciTech Connect

    Schaffer, M.J.

    1997-08-01

    A stabilized pinch configuration is described, consisting of a D-shaped plasma cross section wrapped tightly around a guiding axis. The {open_quotes}helical-D{close_quotes} geometry produces a very large axial (toroidal) transform of magnetic line direction that reverses the pitch of the magnetic lines without the need of azimuthal (poloidal) plasma current. Thus, there is no need of a {open_quotes}dynamo{close_quotes} process and its associated fluctuations. The resulting configuration has the high magnetic shear and pitch reversal of the reversed field pinch (RFP). (Pitch = P = qR, where R = major radius). A helical-D pinch might demonstrate good confinement at q << 1.

  14. Helical spring holder assembly

    NASA Technical Reports Server (NTRS)

    Newman, Wyatt S. (Inventor)

    1987-01-01

    A helically-threaded spring holder on which a helically wound spring is mounted has a groove formed in one side of the thread at the end where the spring engages the spring holder. The groove relieves the portion of the side in which it is formed from restricting the spring against axial movement during deflection of the spring. The circumferential length of this groove is chosen to establish the number of spring coils which can be deflected without contacting the side of the thread. The end of the thread is also made rigid to prevent flexing thereof during maximal elongation of the spring.

  15. Helicity and celestial magnetism

    NASA Astrophysics Data System (ADS)

    Moffatt, H. K.

    2016-06-01

    This informal article discusses the central role of magnetic and kinetic helicity in relation to the evolution of magnetic fields in geophysical and astrophysical contexts. It is argued that the very existence of magnetic fields of the intensity and scale observed is attributable in large part to the chirality of the background turbulence or random-wave field of flow, the simplest measure of this chirality being non-vanishing helicity. Such flows are responsible for the generation of large-scale magnetic fields which themselves exhibit magnetic helicity. In the geophysical context, the turbulence has a `magnetostrophic' character in which the force balance is primarily that between buoyancy forces, Coriolis forces and Lorentz forces associated with the dynamo-generated magnetic field; the dominant nonlinearity here arises from the convective transport of buoyant elements erupting from the `mushy zone' at the inner core boundary. At the opposite extreme, in a highly conducting low-density plasma, the near-invariance of magnetic field topology (and of associated helicity) presents the challenging problem of `magnetic relaxation under topological constraints', of central importance both in astrophysical contexts and in controlled-fusion plasma dynamics. These problems are reviewed and open issues, particularly concerning saturation mechanisms, are reconsidered.

  16. The Helicity of Vortex Filaments.

    NASA Astrophysics Data System (ADS)

    Petrich, Dean; Tao, Louis

    1996-03-01

    The helicity, defined by H = int dV v \\cdot nabla × v, is a conserved quantity of the three-dimensional Euler equations. Traditionally the helicity has been viewed as a measure of the topology of vortex lines, but it is shown that the helicity measures their geometry as well as their topology (J.D. Bekenstein, Physics Letters B), 282 (1992) 44-49.. The existence of helicity-preserving reconnection events is discussed.

  17. Palate size and shape in schizophrenia.

    PubMed

    Delice, Mehtap; Gurbuz, Ozlem; Oflezer, Ceyhan; Kurt, Erhan; Mandali, Gamze

    2016-10-30

    The palate is considered typical of the structures in which schizophrenia-related minor physical anomalies may occur. In this study, we aimed to compare the dimensions and form of palate in patients with schizophrenia with nonpsychiatric controls in a blinded manner. Dental stone casts of 127 patients with schizophrenia and 127 controls were prepared from impressions of the maxillary dental arch. Palate dimensions were measured on the stone casts using a digital caliper and palatometer. Palate length did not differ significantly between the groups, but there was a significant difference in palate width and depth, which were significantly higher in the schizophrenia group. As a result of using multivariate analysis for assessing independent risk factors affecting patients with schizophrenia, furrowed palate shape, palate width, and ellipsoid maxillary dental arch shape were found to be significant. This study also revealed that patients with schizophrenia demonstrate certain gender-related predilections in the differences of palate parameters compared to same-sex controls. As the palate develops in conjunction with both the face and brain, our study findings can significantly contribute to the assumption that there might be structural abnormalities of the palate that could represent specific markers of embryological dysmorphogenesis underlying schizophrenia.

  18. Indolent palatal swelling: Catch 22

    PubMed Central

    Sharma, Preeti; Wadhwan, Vijay; Kumar, K. V. Arun; Venkatesh, Arvind; Thapa, Timsy

    2016-01-01

    We present an interesting but intriguing case of an indolent palatal swelling. The lesion was asymptomatic causing little discomfort to the patient and thus was an incidental clinical finding. Provisional diagnosis was a benign, minor salivary gland tumor. Clinical differential diagnoses included benign lymphoepithelial lesion or mucus extravasation phenomenon. Nevertheless, we also considered malignancies such as mucoepidermoid carcinoma, lymphoma, and neoplasm of the maxillary sinus. However, the histopathology revealed a rare clinicopathologic entity prompting immediate treatment of the lesion. PMID:28356700

  19. Pleomorphic adenoma of the palate.

    PubMed

    Jiménez, Y

    2005-01-01

    An 82-year-old female with a history of high blood pressure and anorexia. She was referred for a long-evolving, asymptomatic large tumor (3x3 cm) on the right side of the palate (fig 1). The patient was wearing total dentures. Intraoral examination revealed a pediculate tumor of the same color as the adjacent mucosa and presenting a firm consistency. An MRI study (fig 2-3) and biopsy were carried out (fig 4-6).

  20. Primary tuberculosis of the palate

    PubMed Central

    Rosado, Pablo; Fuente, Eduardo; Gallego, Lorena; Calvo, Nicolás

    2014-01-01

    Tuberculosis (TB) is a life-threatening infectious disease with a high world incidence. However, TB with oral expression is considered rare. The importance of recognising this entity lies in its early diagnosis and treatment, as it can be easily confused with neoplastic or traumatic ulcers. We present a case of a primary TB located in the hard palate and gingiva in an 88-year-old woman. PMID:24925532

  1. Primary tuberculosis of the palate.

    PubMed

    Rosado, Pablo; Fuente, Eduardo; Gallego, Lorena; Calvo, Nicolás

    2014-06-12

    Tuberculosis (TB) is a life-threatening infectious disease with a high world incidence. However, TB with oral expression is considered rare. The importance of recognising this entity lies in its early diagnosis and treatment, as it can be easily confused with neoplastic or traumatic ulcers. We present a case of a primary TB located in the hard palate and gingiva in an 88-year-old woman.

  2. Helically Coiled Graphene Nanoribbons.

    PubMed

    Daigle, Maxime; Miao, Dandan; Lucotti, Andrea; Tommasini, Matteo; Morin, Jean-François

    2017-03-07

    Graphene is a zero-gap, semiconducting 2D material that exhibits outstanding charge-transport properties. One way to open a band gap and make graphene useful as a semiconducting material is to confine the electron delocalization in one dimension through the preparation of graphene nanoribbons (GNR). Although several methods have been reported so far, solution-phase, bottom-up synthesis is the most promising in terms of structural precision and large-scale production. Herein, we report the synthesis of a well-defined, helically coiled GNR from a polychlorinated poly(m-phenylene) through a regioselective photochemical cyclodehydrochlorination (CDHC) reaction. The structure of the helical GNR was confirmed by (1) H NMR, FT-IR, XPS, TEM, and Raman spectroscopy. This Riemann surface-like GNR has a band gap of 2.15 eV and is highly emissive in the visible region, both in solution and the solid state.

  3. Analysis of Helical Waveguide.

    DTIC Science & Technology

    1985-12-23

    tube Efficiency Helix structure Backward wave oscillation Gain 19. ABSTRACT (Continue on reverse if necessary and identofy by block number) The...4,vailabilitY CCdes -vai aidIorDist spec a ." iii "- -. .5- S.. . ANALYSIS OF HELICAL WAVEGUIDE I. INTRODUCTION High power (- 10 kW) and broadband ...sys- tems. The frequency range of interest is 60-100 GHz. In this frequency range, the conventional slow wave circuits such as klystrons and TWTs have

  4. 3-D shape analysis of palatal surface in patients with unilateral complete cleft lip and palate.

    PubMed

    Rusková, Hana; Bejdová, Sárka; Peterka, Miroslav; Krajíček, Václav; Velemínská, Jana

    2014-07-01

    Facial development of patients with unilateral complete cleft lip and palate (UCLP) is associated with many problems including deformity of the palate. The aim of this study was to evaluate palatal morphology and variability in patients with UCLP compared with Czech norms using methods of geometric morphometrics. The study was based on virtual dental cast analysis of 29 UCLP patients and 29 control individuals at the age of 15 years. The variability of palatal shape in UCLP patients was greater than that in nonclefted palates. Only 24% of clefted palates fell within the variability of controls. The palatal form of UCLP patients (range from 11.8 to 17.2 years) was not correlated with age. Compared with control palates, palates of UCLP patients were narrower, more anteriorly than posteriorly. Apart from the praemaxilla region, they were also shallower, and the difference increased posteriorly. The UCLP palate was characterised by the asymmetry of its vault. The maximum height of the palatal vault was anterior on the clefted side, whereas it was posterior on the nonclefted side. The slope of the UCLP palate was more inclined compared with the control group. The praemaxilla was therefore situated more inferiorly.

  5. Helically linked mirror arrangement

    SciTech Connect

    Ranjan, P.

    1986-08-01

    A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average ..beta.. and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned.

  6. Cranial strains and malocclusion VIII: palatal expansion.

    PubMed

    James, Gavin; Strokon, Dennis

    2009-01-01

    Current techniques for palatal expansion are reviewed. Pre-treatment asymmetry of the palate and maxillary arch is shown to be almost universal and is not randomly distributed. The use of a symmetrical expansion appliance does not necessarily result in a symmetrical arch. ALF appliances provide a means of achieving orthopedic, symmetrical expansion of the palate by using very light force. This is demonstrated in seven subjects. It is argued that rapid palatal expansion is an inappropriate, potentially iatrogenic procedure which no longer has a place in the orthodontic armamentarium.

  7. Improving Informed Consent for Cleft Palate Repair

    ClinicalTrials.gov

    2017-03-07

    Cleft Palate; Jaw Abnormalities; Maxillofacial Abnormalities; Mouth Abnormalities; Congenital Abnormalities; Jaw Diseases; Musculoskeletal Diseases; Craniofacial Abnormalities; Musculoskeletal Abnormalities; Stomatognathic Diseases; Stomatognathic System Abnormalities

  8. [Proper technics and the reduction of radiation in helical computed tomography].

    PubMed

    Cordoliani, Y S; Hazebroucq, V; Sarrazin, J L; Lévêque, C; Marque, B; Goasdoué, P

    1999-02-01

    Helical computed tomography is the main source of ionizing radiation delivery in diagnostic radiology. For each series, average radiation dose is between 20 and 30 mGy. This dose can potentially be reduced by decreasing intensity or voltage and by increasing pitch. Helical acquisition allows reformating of images with smaller increment or different obliquity, and avoids additional irradiation. Hardware and software devices designed for dose reduction must be systematically used. Users of CT systems should be aware of radiation dose delivered with CT and must carefully assess the need of each additional acquisition. Obsolete habits, as gantry tilting for lumbar CT, which increases patient exposure, must be given up. Rational use of helical CT decreases radiation exposure and gains time, whereas thoughtless use increases radiation exposure without real benefit.

  9. Iterative image reconstruction for limited-angle inverse helical cone-beam computed tomography.

    PubMed

    Yu, Wei; Zeng, Li

    2016-01-01

    Helical trajectory satisfying the condition of exact reconstruction, has been widely utilized in the commercial computed tomography (CT). While limited by the scanning environment in some practical applications, the conventional helical cone-beam CT imaging is hard to complete, thus, developing an imaging system suited for long-object may be valuable. Three-dimensional C-arm CT is an innovative imaging technique which has been greatly concerned. Since there is a high degree of freedom of C-arm, more flexible image acquisition trajectories for 3D imaging can be achieved. In this work, a fast iterative reconstruction algorithm based on total variation minimization is developed for a trajectory of limited-angle inverse helical cone-beam CT, which can be applied to detect long-object without slip-ring technology. The experimental results show that the developed algorithm can yield reconstructed images of low noise level and high image quality.

  10. Sinonasal Angiomatous Polyp: Evaluation With 2-Phase Helical Computed Tomography

    PubMed Central

    Ding, Changwei; Wang, Qiushi; Guo, Qiyong; Wang, Zhenhai; Lu, Xiaomei; Zhang, Jun

    2015-01-01

    Abstract Sinonasal angiomatous polyp (SAP) is a rare benign nontumorous lesion and previously considered lack of characteristic computed tomography (CT) findings. This study aimed to evaluate 2-phase helical CT for characterization of SAP. Twelve patients with pathologically confirmed SAP underwent 2-phase helical CT preoperatively. After injection of 80 mL contrast material at a rate of 3 mL/s, early and delayed phases were obtained with delays of 30 and 120 s, respectively. The degree and pattern of enhancement were visually analyzed. The attenuation changes were also analyzed quantitatively by measuring CT values and compared with those of the internal maxillary artery (IMA). All 12 cases showed vessel-like marked heterogeneous enhancement at both early and delayed phases. An irregular linear, nodular, and patchy enhancement pattern was found at the early phase, and enlarged and fused together, that is, progressive enhancement pattern was found at the delayed phase. There was no significant difference between the CT values of SAP and those of the IMA at the plain, arterial phase, and delayed phase (53 ± 6 Hounsfield units [HU] vs 56 ± 7 HU, 187 ± 56 HU vs 209 ± 71 HU, and 143 ± 22 HU vs 139 ± 19 HU, respectively, P = 0.361, 0.429, and 0.613, respectively). Vessel-like marked heterogeneous enhancement was a characteristic CT feature of SAP, and progressive enhancement on 2-phase helical CT could further convince the diagnosis. PMID:26200632

  11. Magnetic helicity in astrophysical dynamos

    NASA Astrophysics Data System (ADS)

    Candelaresi, Simon

    2012-09-01

    The broad variety of ways in which magnetic helicity affects astrophysical systems, in particular dynamos, is discussed. The so-called alpha effect is responsible for the growth of large-scale magnetic fields. The conservation of magnetic helicity, however, quenches the alpha effect, in particular for high magnetic Reynolds numbers. Predictions from mean-field theories state particular power law behavior of the saturation strength of the mean fields, which we confirm in direct numerical simulations. The loss of magnetic helicity in the form of fluxes can alleviate the quenching effect, which means that large-scale dynamo action is regained. Physically speaking, galactic winds or coronal mass ejections can have fundamental effects on the amplification of galactic and solar magnetic fields. The gauge dependence of magnetic helicity is shown to play no effect in the steady state where the fluxes are represented in form of gauge-independent quantities. This we demonstrate in the Weyl-, resistive- and pseudo Lorentz-gauge. Magnetic helicity transport, however, is strongly affected by the gauge choice. For instance the advecto-resistive gauge is more efficient in transporting magnetic helicity into small scales, which results in a distinct spectrum compared to the resistive gauge. The topological interpretation of helicity as linking of field lines is tested with respect to the realizability condition, which imposes a lower bound for the spectral magnetic energy in presence of magnetic helicity. It turns out that the actual linking does not affect the relaxation process, unlike the magnetic helicity content. Since magnetic helicity is not the only topological variable, I conduct a search for possible others, in particular for non-helical structures. From this search I conclude that helicity is most of the time the dominant restriction in field line relaxation. Nevertheless, not all numerical relaxation experiments can be described by the conservation of magnetic helicity

  12. Impact of helical computed tomography on the outcomes of emergency department patients with suspected appendicitis.

    PubMed

    Torbati, Sam S; Guss, David A

    2003-08-01

    To assess the impact of an emergency department (ED) guideline employing selective use of helical computed tomography (CT) on clinical outcomes of female patients with suspected appendicitis. All patients presenting with suspected appendicitis were prospectively enrolled and managed in accordance with a guideline incorporating selective use of helical CT. Although not the objective of this investigation, male patients were included for purposes of comparison. Patients with clinically evident appendicitis were referred to the surgical service, and patients with equivocal presentations were studied with helical CT. Patients were followed to final surgical or clinical outcomes. Outcome measures included time from ED presentation to laparotomy and rate of appendiceal perforation. These measures were compared with those of a historical cohort of patients preceding the use of helical CT. A total of 310 consecutive patients with suspected appendicitis were enrolled; 92 had appendicitis. Sixty patients were referred to the surgical service without helical CT, and 41 had appendicitis (68%). Helical CT was performed on 250 patients; 51 had appendicitis (20%). For males, the mean interval from ED presentation to laparotomy was 559 minutes (95% CI = 444 to 674 minutes) during guideline use and 480 minutes (95% CI = 405 to 555 minutes) before. This interval for females was 433 minutes (95% CI = 326 to 540 minutes) during guideline use and 710 minutes (95% CI = 558 to 862 minutes) before. Appendiceal perforation rate for males was 0.25 (95% CI = 0.14 to 0.36) during guideline use and 0.38 (95% CI = 0.29 to 0.47) before; perforation rate for females was 0.06 (95% CI = -0.05 to 0.17) during guideline use and 0.23 (95% CI = 0.14 to 0.32) before. Helical CT had 92% sensitivity, 97% specificity, and 96% accuracy in diagnosing appendicitis. Helical CT is highly accurate in detecting appendicitis in patients with equivocal ED presentations. The use of a guideline employing selective

  13. Mesenchymal fibroblast growth factor receptor signaling regulates palatal shelf elevation during secondary palate formation

    PubMed Central

    Yu, Kai; Karuppaiah, Kannan; Ornitz, David M.

    2015-01-01

    Palatal shelf elevation is an essential morphogenetic process during secondary palate closure and failure or delay of palatal shelf elevation is a common cause of cleft palate, one of the most common birth defects in humans. Here, we studied the role of mesenchymal fibroblast growth factor receptor (FGFR) signaling during palate development by conditional inactivation of Fgfrs using a mesenchyme-specific Dermo1-Cre driver. We showed that Fgfr1 is expressed throughout the palatal mesenchyme and Fgfr2 is expressed in the medial aspect of the posterior palatal mesenchyme overlapping with Fgfr1. Mesenchyme-specific disruption of Fgfr1 and Fgfr2 affected palatal shelf elevation and resulted in cleft palate. We further showed that both Fgfr1 and Fgfr2 are expressed in mesenchymal tissues of the mandibular process but display distinct expression patterns. Loss of mesenchymal FGFR signaling reduced mandibular ossification and lower jaw growth resulting in abnormal tongue insertion in the oral-nasal cavity. We propose a model to explain how redundant Fgfr1 and Fgfr2 expression in the palatal and mandibular mesenchyme regulates shelf medial wall protrusion and growth of the mandible to coordinate the craniofacial tissue movements that are required for palatal shelf elevation. PMID:26250517

  14. Mesenchymal fibroblast growth factor receptor signaling regulates palatal shelf elevation during secondary palate formation.

    PubMed

    Yu, Kai; Karuppaiah, Kannan; Ornitz, David M

    2015-11-01

    Palatal shelf elevation is an essential morphogenetic process during secondary palate closure and failure or delay of palatal shelf elevation is a common cause of cleft palate, one of the most common birth defects in humans. Here, we studied the role of mesenchymal fibroblast growth factor receptor (FGFR) signaling during palate development by conditional inactivation of Fgfrs using a mesenchyme-specific Dermo1-Cre driver. We showed that Fgfr1 is expressed throughout the palatal mesenchyme and Fgfr2 is expressed in the medial aspect of the posterior palatal mesenchyme overlapping with Fgfr1. Mesenchyme-specific disruption of Fgfr1 and Fgfr2 affected palatal shelf elevation and resulted in cleft palate. We further showed that both Fgfr1 and Fgfr2 are expressed in mesenchymal tissues of the mandibular process but display distinct expression patterns. Loss of mesenchymal FGFR signaling reduced mandibular ossification and lower jaw growth resulting in abnormal tongue insertion in the oral-nasal cavity. We propose a model to explain how redundant Fgfr1 and Fgfr2 expression in the palatal and mandibular mesenchyme regulates shelf medial wall protrusion and growth of the mandible to coordinate the craniofacial tissue movements that are required for palatal shelf elevation. © 2015 Wiley Periodicals, Inc.

  15. Strategies to Improve Regeneration of the Soft Palate Muscles After Cleft Palate Repair

    PubMed Central

    Carvajal Monroy, Paola L.; Grefte, Sander; Kuijpers-Jagtman, Anne Marie; Wagener, Frank A.D.T.G.

    2012-01-01

    Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. These patients are unable to separate the nasal from the oral cavity leading to air loss during speech. Although surgical repair ameliorates soft palate function by joining the clefted muscles of the soft palate, optimal function is often not achieved. The regeneration of muscles in the soft palate after surgery is hampered because of (1) their low intrinsic regenerative capacity, (2) the muscle properties related to clefting, and (3) the development of fibrosis. Adjuvant strategies based on tissue engineering may improve the outcome after surgery by approaching these specific issues. Therefore, this review will discuss myogenesis in the noncleft and cleft palate, the characteristics of soft palate muscles, and the process of muscle regeneration. Finally, novel therapeutic strategies based on tissue engineering to improve soft palate function after surgical repair are presented. PMID:22697475

  16. Strategies to improve regeneration of the soft palate muscles after cleft palate repair.

    PubMed

    Carvajal Monroy, Paola L; Grefte, Sander; Kuijpers-Jagtman, Anne Marie; Wagener, Frank A D T G; Von den Hoff, Johannes W

    2012-12-01

    Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. These patients are unable to separate the nasal from the oral cavity leading to air loss during speech. Although surgical repair ameliorates soft palate function by joining the clefted muscles of the soft palate, optimal function is often not achieved. The regeneration of muscles in the soft palate after surgery is hampered because of (1) their low intrinsic regenerative capacity, (2) the muscle properties related to clefting, and (3) the development of fibrosis. Adjuvant strategies based on tissue engineering may improve the outcome after surgery by approaching these specific issues. Therefore, this review will discuss myogenesis in the noncleft and cleft palate, the characteristics of soft palate muscles, and the process of muscle regeneration. Finally, novel therapeutic strategies based on tissue engineering to improve soft palate function after surgical repair are presented.

  17. Palatable Meal Anticipation in Mice

    PubMed Central

    Hsu, Cynthia T.; Patton, Danica F.; Mistlberger, Ralph E.; Steele, Andrew D.

    2010-01-01

    The ability to sense time and anticipate events is a critical skill in nature. Most efforts to understand the neural and molecular mechanisms of anticipatory behavior in rodents rely on daily restricted food access, which induces a robust increase of locomotor activity in anticipation of daily meal time. Interestingly, rats also show increased activity in anticipation of a daily palatable meal even when they have an ample food supply, suggesting a role for brain reward systems in anticipatory behavior, and providing an alternate model by which to study the neurobiology of anticipation in species, such as mice, that are less well adapted to “stuff and starve” feeding schedules. To extend this model to mice, and exploit molecular genetic resources available for that species, we tested the ability of wild-type mice to anticipate a daily palatable meal. We observed that mice with free access to regular chow and limited access to highly palatable snacks of chocolate or “Fruit Crunchies” avidly consumed the snack but did not show anticipatory locomotor activity as measured by running wheels or video-based behavioral analysis. However, male mice receiving a snack of high fat chow did show increased food bin entry prior to access time and a modest increase in activity in the two hours preceding the scheduled meal. Interestingly, female mice did not show anticipation of a daily high fat meal but did show increased activity at scheduled mealtime when that meal was withdrawn. These results indicate that anticipation of a scheduled food reward in mice is behavior, diet, and gender specific. PMID:20941366

  18. Palatal Mucormycosis in An Infant.

    PubMed

    Srivastava, Nikhil; Bansal, Vishal; Kantoor, Pallavi

    2015-01-01

    The maxilla rarely undergoes necrosis due to its rich vascularity. Maxillary necrosis can occur due to bacterial infections, viral infections, or fungal infections. Mucormycosis is an opportunistic fulminant fungal infection that mainly infects immunocompromised patients. The fungus invades the arteries, leading to thrombosis that subsequently causes necrosis of hard and soft tissues. The occurrence of mucormycosis is not considered rare in the jaws of adults, but involvement of the maxilla in infants is not usually seen. The purpose of this report is to discuss the diagnosis and management of a rare case of mucormycosis in the palate of a two-month-old boy.

  19. Palatability, Familiarity, and Underage, Immoderate Drinking

    ERIC Educational Resources Information Center

    Lemon, Jim; Stevenson, Richard; Gates, Peter; Copeland, Jan

    2011-01-01

    Data gathered in a study of palatability ("liking") and familiarity ratings of alcoholic and nonalcoholic beverages by 350 subjects from 12 to 30 years of age included the usual number of drinks consumed. Blind ratings of palatability and familiarity for the beverages were tested for association with immoderate drinking (more than four for males,…

  20. Palatability, Familiarity, and Underage, Immoderate Drinking

    ERIC Educational Resources Information Center

    Lemon, Jim; Stevenson, Richard; Gates, Peter; Copeland, Jan

    2011-01-01

    Data gathered in a study of palatability ("liking") and familiarity ratings of alcoholic and nonalcoholic beverages by 350 subjects from 12 to 30 years of age included the usual number of drinks consumed. Blind ratings of palatability and familiarity for the beverages were tested for association with immoderate drinking (more than four for males,…

  1. [Helical computerized tomography of the thorax in the diagnosis of unresolved chronic pulmonary thromboembolism].

    PubMed

    Matheus, M C; Sandoval Zárate, J; Criales Cortés, J L; Martínez-Guerra, M L; Pulido, T; Palomar Lever, A; Gómez González, A; Santos, E; Barragán, R; Fernández, R A; Cardoso Ramón, M

    2000-01-01

    We assessed the diagnostic usefulness of helical CT scan of the thorax in the setting of chronic thromboembolic pulmonary hypertension by prospectively comparing the results of helical CT scan to those of the pulmonary angiogram (gold standard). We studied 40 patients with diagnosis of pulmonary hypertension of diverse etiology (mean age: 40.7 +/- 12 y.o.; mean systolic pulmonary artery pressure: 91 +/- 33 mmHg)). Thirty of these patients fulfilled the diagnostic criteria of chronic thromboembolic pulmonary hypertension and the other ten were used as controls. Diagnosis in control patients included: primary pulmonary hypertension (4); patent ductus arteriosus (2); atrial septal defect (1); rheumatic valve disease (1); ischemic heart disease (1); and acute pulmonary embolism (1). Both helical CT scan and pulmonary angiogram were part of the routine diagnostic work up of these patients, and were, performed and interpreted almost simultaneously (within one week) by a different group of investigators in a blind manner. Only the diagnostic accuracy of the method regarding central (major arteries) vascular lesions was evaluated. Helical CT scan had an overall sensitivity of 100% (29/29), and a specificity of 91% (10/11). Positive predictive and negative predictive values were 96.6% (29/30) and 100% (10/10), respectively. Overall diagnostic accuracy was 97.5% (39/40). We conclude that helical CT scan of the thorax is an excellent alternative approach for the diagnosis of major arteries lesions in the setting of chronic thromboembolic pulmonary hypertension.

  2. Prediction of buried helices in multispan alpha helical membrane proteins.

    PubMed

    Adamian, Larisa; Liang, Jie

    2006-04-01

    Analysis of a database of structures of membrane proteins shows that membrane proteins composed of 10 or more transmembrane (TM) helices often contain buried helices that are inaccessible to phospholipids. We introduce a method for identifying TM helices that are least phospholipid accessible and for prediction of fully buried TM helices in membrane proteins from sequence information alone. Our method is based on the calculation of residue lipophilicity and evolutionary conservation. Given that the number of buried helices in a membrane protein is known, our method achieves an accuracy of 78% and a Matthew's correlation coefficient of 0.68. A server for this tool (RANTS) is available online at http://gila.bioengr.uic.edu/lab/.

  3. Helical phases in superconductors

    NASA Astrophysics Data System (ADS)

    Sandhu, Raminder P. Kaur

    In conventional superconductors, the Cooper pairs are formed from quasiparticles with opposite momentum and spins because of the degeneracy of the quasiparticles under time reversal and inversion. The absence of any of these symmetries will have pronounced effects on superconducting states. Time reversal symmetry can be broken in the presence of magnetic impurities or by the application of a magnetic field. Similarly, the dislocation of crystal ions from their higher symmetric positions can cause broken inversion symmetry. We studied the effects of broken time reversal and inversion symmetries on unconventional superconductors, such as high temperature cuprates, Sr2RuO 4, and CePt3Si. In the cuprates, the superconducting state exists near the antiferromagnetic order. Sr2RuO4 and CePt3Si do not have spatial inversion, and the superconducting states coexist with magnetic order. In cuprates, the broken time reversal symmetry has been reported in the pseudogap phase which will effect the d-wave superconducting state of underdoped regime. On the basis of symmetry analysis we found that a mixture of spin-singlet and -triplet state, d+ip, which is shown to give rise to a helical superconducting phase. Consequences of this d+ip state on Josephson experiments are also discussed. Sr2RuO 4 is known to be another broken time reversal superconductor with spin triplet superconductivity. The widely believed superconducting state, the chiral p wave state, has been extensively studied through Ginzburg Landau theory, but the predictions for this state contradict some experimental observations like anisotropy in the upper critical field, and the existence of a second vortex state. We have formalize quasiclassical theory to find the origin of these contradictions, and also extended the theory to study other possible super-conducting states. Surprisingly, we find that a superconducting state corresponding to freely rotating in-plane d-vector explains the existing experimental results

  4. Tbx1 is Necessary for Palatal Elongation and Elevation

    PubMed Central

    Goudy, Steven; Law, Amy; Sanchez, Gabriela; Baldwin, H. Scott; Brown, Christopher

    2010-01-01

    The transcription factor TBX1 is a key mediator of developmental abnormalities associated with DiGeorge/Velocardiofacial Syndrome. Studies in mice have demonstrated that decreased dosage of Tbx1 results in defects in pharyngeal arch, cardiovascular, and craniofacial development. The role of Tbx1 in cardiac development has been intensely studied; however, its role in palatal development is poorly understood. By studying the Tbx1-/- mice we found defects during the critical points of palate elongation and elevation. The intrinsic palate defects in the Tbx1-/- mice were determined by measuring changes in palate shelf length, proliferation, apoptosis, expression of relevant growth factors, and in palate fusion assays. Tbx1-/- embryos exhibit cleft palate with failed palate elevation in 100% and abnormal palatal-oral fusions in 50%. In the Tbx1-/- mice the palate shelf length was reduced and tongue height was greater, demonstrating a physical impediment to palate elevation and apposition. In vitro palate fusion assays demonstrate that Tbx1-/- palate shelves are capable of fusion but a roller culture assay showed that the null palatal shelves were unable to elongate. Diminished hyaluronic acid production in the Tbx1-/- palate shelves may explain failed palate shelf elevation. In addition, cell proliferation and apoptosis were perturbed in Tbx1-/- palates. A sharp decrease of Fgf8 expression was detected in the Tbx1-/- palate shelves, suggesting that Fgf8 is dependent on Tbx1 in the palate. Fgf10 is also up-regulated in the Tbx1-/- palate shelves and tongue. These data demonstrate that Tbx1 is a critical transcription factor that guides palatal elongation and elevation and that Fgf8 expression in the palate is Tbx1-dependent. PMID:20214979

  5. [Application of multislice helical computed tomography in maxillofacial distraction osteogenesis].

    PubMed

    Niu, Xue-gang; Zhao, Yi-min; Han, Xiao-xian; Hao, Yong; Men, Shen-li

    2008-12-01

    To develop the method and investigate the value of the application of multislice helical computed tomography (CT) in the maxillofacial distraction osteogenesis. Twelve cases of maxillofacial distraction osteogenesis (3 in zygoma, 2 in maxilla, and 7 in mandible) were scanned by the multislice helical CT, then the reconstruction of three dimensional and fault image and the relative measurement were carried out to study the effect of distraction and osteogenesis. The three dimensional image provided clear and high resolution stereoscopic view that the effect of distraction osteogenesis could be evaluated easily and exactly. The fault image could be set up in private computer by Mimics and the measurements, such as distance, thickness and density, could be performed as expected. The effect of 12 cases was satisfied, and the average distracted distance was 16.73 mm. Basing on multislice helical CT scanning, the high resolution image reconstruction and relative measurement data could be obtained which could meet the need of clear and direct observation. Its application in the maxillofacial distraction osteogenesis is expecting and promising.

  6. Helicity in dynamic atmospheric processes

    NASA Astrophysics Data System (ADS)

    Kurgansky, M. V.

    2017-03-01

    An overview on the helicity of the velocity field and the role played by this concept in modern research in the field of geophysical fluid dynamics and dynamic meteorology is given. Different (both previously known in the literature and first presented) formulations of the equation of helicity balance in atmospheric motions (including those with allowance for effects of air compressibility and Earth's rotation) are brought together. Equations and relationships are given which are valid in different approximations accepted in dynamic meteorology: Boussinesq approximation, quasi-static approximation, and quasi-geostrophic approximation. Emphasis is placed on the analysis of helicity budget in large-scale quasi-geostrophic systems of motion; a formula for the helicity flux across the upper boundary of the nonlinear Ekman boundary layer is given, and this flux is shown to be exactly compensated for by the helicity destruction inside the Ekman boundary layer.

  7. Helicity patterns on the Sun

    NASA Astrophysics Data System (ADS)

    Pevtsov, A.

    Solar magnetic fields exhibit hemispheric preference for negative (pos- itive) helicity in northern (southern) hemisphere. The hemispheric he- licity rule, however, is not very strong, - the patterns of opposite sign helicity were observed on different spatial scales in each hemisphere. For instance, many individual sunspots exhibit patches of opposite he- licity inside the single polarity field. There are also helicity patterns on scales larger than the size of typical active region. Such patterns were observed in distribution of active regions with abnormal (for a give hemisphere) helicity, in large-scale photospheric magnetic fields and coronal flux systems. We will review the observations of large-scale pat- terns of helicity in solar atmosphere and their possible relationship with (sub-)photospheric processes. The emphasis will be on large-scale pho- tospheric magnetic field and solar corona.

  8. Coronary CT angiography with low radiation dose.

    PubMed

    Xu, Lei; Zhang, Zhaoqi

    2010-02-01

    With the introduction of 64-slice CT and dual-source CT technology, coronary CT angiography(CCTA) has emerged as a useful diagnostic imaging modality for the noninvasive assessment of coronary heart disease. Recently, the risks associated with ionizing radiation on CT have raised serious concerns.The main concern of exposure to ionizing radiation is the potential risk of cancer. CCTA involves much higher radiation dose with the advances in the spatial and temporal resolution of cardiac CT. Currently,various dose-saving algorithms, such as ECG (electrocardiography)-based dose modulation, reduced tube voltage, and prospective ECG gating, high-pitch helical scanning are available to lower radiation exposure during cardiac CT. Therefore, careful selection of CT scanning protocols is needed to keep the radiation exposure 'as low as reasonably achievable (ALARA)'. In this review we will discuss the radiation dose safety issues, the measurement of radiation dose and current use of dose-saving techniques in CCTA.

  9. Magnetic design constraints of helical solenoids

    SciTech Connect

    Lopes, M. L.; Krave, S. T.; Tompkins, J. C.; Yonehara, K.; Flanagan, G.; Kahn, S. A.; Melconian, K.

    2015-01-30

    Helical solenoids have been proposed as an option for a Helical Cooling Channel for muons in a proposed Muon Collider. Helical solenoids can provide the required three main field components: solenoidal, helical dipole, and a helical gradient. In general terms, the last two are a function of many geometric parameters: coil aperture, coil radial and longitudinal dimensions, helix period and orbit radius. In this paper, we present design studies of a Helical Solenoid, addressing the geometric tunability limits and auxiliary correction system.

  10. The mechanism of TGF-β signaling during palate development

    PubMed Central

    Iwata, J; Parada, C; Chai, Y

    2012-01-01

    Cleft palate, a malformation of the secondary palate development, is one of the most common human congenital birth defects. Palate formation is a complex process resulting in the separation of the oral and nasal cavities that involves multiple events, including palatal growth, elevation, and fusion. Recent findings show that transforming growth factor beta (TGF-β) signaling plays crucial roles in regulating palate development in both the palatal epithelium and mesenchyme. Here, we highlight recent advances in our understanding of TGF-β signaling during palate development. PMID:21395922

  11. The use of helical computed tomographic scan to assess bony physeal bridges.

    PubMed

    Loder, R T; Swinford, A E; Kuhns, L R

    1997-01-01

    Coronal and sagittal reformatted images of the physis obtained with the helical computed tomography (CT) scanner were studied in five children. This technique allows tomographic slices at 1.0-mm thickness and can be performed in approximately 20 s. The distal femora were studied in two children, the distal tibia in two children, and the distal radius in one child. In three children, after physeal mapping, bar resections were performed. In all cases, the location and size of the bar was accurately predicted by the map constructed from the helical CT scan. We recommend the helical CT scan to prepare physeal maps to determine the extent and location of physeal bony bars because of excellent bony detail, radiation doses one half to one quarter those of conventional tomography, and the rapidity of scanning, which bypasses the need for sedation.

  12. Helical Nanofilament Phases

    SciTech Connect

    L Hough; H Jung; D Kruerke; M Heberling; M Nakata; C Jones; D Chen; D Link; N Clark; et al.

    2011-12-31

    In the formation of chiral crystals, the tendency for twist in the orientation of neighboring molecules is incompatible with ordering into a lattice: Twist is expelled from planar layers at the expense of local strain. We report the ordered state of a neat material in which a local chiral structure is expressed as twisted layers, a state made possible by spatial limitation of layering to a periodic array of nanoscale filaments. Although made of achiral molecules, the layers in these filaments are twisted and rigorously homochiral - a broken symmetry. The precise structural definition achieved in filament self-assembly enables collective organization into arrays in which an additional broken symmetry - the appearance of macroscopic coherence of the filament twist-produces a liquid crystal phase of helically precessing layers.

  13. Helical Siberian snakes

    SciTech Connect

    Courant, E.D.

    1988-01-01

    To eliminate spin resonances in circular accelerators ''Siberian Snakes'' may be inserted at one or more azimuths in such a way that the overall spin precession tune ..nu../sub s/ equals 1/2. A snake is a sequence of horizontal and vertical deflection magnets whose overall effect is to rotate the spin by ..pi.. about an axis in the plane of the orbit, either longitudinal or transverse or any angle /var phi/ in between. At the same time the magnets of the snake should be arranged so as to produce zero net deflection and displacement of the particle orbit. We investigate here how the orbit deflections can be made small by using helical deflecting magnets rather than discrete horizontal and vertical deflectors.

  14. Mixing in Helical Pipes

    NASA Astrophysics Data System (ADS)

    Gratton, Michael B.; Bernoff, Andrew J.

    2001-11-01

    We consider advection and diffusion of a passive scalar in a helical pipe. By assuming that the curvature and torsion are small (equivalent to small Dean number) and the Reynolds number is moderate, we can use a closed form approximation, due to Dean (1927) and Germano (1982), for the induced recirculation. We investigate the problem numerically using a split-step particle method for a variety of localized initial conditions. The problem is governed by two parameters: a nondimensional diffusion constant D (typically small), and the scaled ratio of torsion to curvature λ. At small times, the longitudinal width of the particle distribution, σ, is governed by diffusive effects (σ ∝ √Dt). At large times, Taylor diffusion dominates (σ ∝ √t/D). However, at intermediate times, a ballistic region exists where the width spreads linearly, as postulated by Mezic & Wiggins (1994). We also discuss how these various behaviors scale with the parameters D and λ.

  15. The advanced helical generator

    NASA Astrophysics Data System (ADS)

    Reisman, D. B.; Javedani, J. B.; Ellsworth, G. F.; Kuklo, R. M.; Goerz, D. A.; White, A. D.; Tallerico, L. J.; Gidding, D. A.; Murphy, M. J.; Chase, J. B.

    2010-03-01

    A high explosive pulsed power generator called the advanced helical generator (AHG) has been designed, built, and successfully tested. The AHG incorporates design principles of voltage and current management to obtain a high current and energy gain. Its design was facilitated by the use of modern modeling tools as well as high precision manufacture. The result was a first-shot success. The AHG delivered 16 MA of current and 11 MJ of energy to a quasistatic 80 nH inductive load. A current gain of 160 times was obtained with a peak exponential rise time of 20 μs. We will describe in detail the design and testing of the AHG.

  16. The Advanced Helical Generator

    SciTech Connect

    Reisman, D B; Javedani, J B; Ellsworth, G F; Kuklo, R M; Goerz, D A; White, A D; Tallerico, L J; Gidding, D A; Murphy, M J; Chase, J B

    2009-10-26

    A high explosive pulsed power (HEPP) generator called the Advanced Helical Generator (AHG) has been designed, built, and successfully tested. The AHG incorporates design principles of voltage and current management to obtain a high current and energy gain. Its design was facilitated by the use of modern modeling tools as well as high precision manufacture. The result was a first-shot success. The AHG delivered 16 Mega-Amperes of current and 11 Mega-Joules of energy to a quasi-static 80 nH inductive load. A current gain of 154 times was obtained with a peak exponential rise time of 20 {micro}s. We will describe in detail the design and testing of the AHG.

  17. Eosinophilic Granuloma Presenting as Palatal Swelling

    PubMed Central

    Babu, B. Balaji; Nadendla, Lakshmi Kavitha; Madki, Pooja

    2016-01-01

    Swellings involving palate can be challenging to diagnose for the clinician as they have wide range of origin which can result from developmental, inflammatory, reactive or a neoplastic process. The clinical presentation of these swellings is similar and difficult to differentiate from each other. So it is important to take proper history from the patient and subject the patient to appropriate laboratory and radiographic investigations and finally biopsy is mandatory for accurate diagnosis. Thus, this article highlights on various common palatal swellings, their clinical presentation, and differential diagnosis helpful for proper diagnosis of swellings associated with palate. PMID:27891486

  18. Observance of Kassowitz law-late congenital syphilis: Palatal perforation and saddle nose deformity as presenting features.

    PubMed

    Balaji, Govindan; Kalaivani, Subramanian

    2013-01-01

    Late congenital syphilis refers to the people with syphilis from the age of 2 to 30 years. We report a case of late congenital syphilis in a 9 year old girl with perforation of palate and saddle nose deformity. Kassowitz law was also observed (if a woman with untreated syphilis has series of pregnancies, the likelihood of infection of the fetus in later pregnancies becomes less). Venereal Disease Research Laboratory (VDRL) and Treponema pallidum hemagglutination (TPHA) were reactive. Computed tomography (CT) scan of paranasal sinus showed maxillary and nasal polyps. The case reported here is a rare presentation of late congenital syphilis with perforation of palate and saddle nose deformity.

  19. Histology of palate and soft palate tonsil of collared peccary (Tayassu tajacu).

    PubMed

    Teófilo, T S; Morais, M R P T; Dias, G F; Diniz, A N; Chaves, H S A; Fontenele-Neto, J D

    2014-10-01

    Peccaries are characterized by a prominent skin gland, known as scent gland, which is located in the middle of the rump. These animals are able to survive in a great variety of habitats, from humid tropical forests to semi-arid areas. They are omnivorous animals, and their diet includes fibrous material, vegetables, fruits, small vertebrates and insects. Collared peccary hard palate and soft palate tonsils were studied, macroscopic morphometric data were collected and tissue samples were paraffin-embedded. Sections were stained with HE, Gomori's trichrome and von Kossa; the first two were used to study general organization and the latter to detect calcium deposits. The hard palate showed one incisive papilla followed by several rugae united by a distinct raphe. The hard palate is lined by a keratinised squamous epithelium resting on a dense connective, whereas in the soft palate, the epithelium is parakeratinised and showed lymphocyte infiltration. The palate showed several pacinian corpuscles in the propria-submucosa. Two ovoid-shaped tonsils were found in the soft palate, and several crypts were observed on its surface. The epithelium was highly infiltrated by lymphocytes, and within the crypts, tonsilloliths were frequently observed. The study showed that the general organization of collared peccary palate is similar to other species, but in its oropharynx, only the soft palate tonsil was present and the pacinian corpuscles formed small aggregates. © 2013 Blackwell Verlag GmbH.

  20. Plasma driven by helical electrodes

    NASA Astrophysics Data System (ADS)

    Akcay, Cihan; Finn, John; Nebel, Richard; Barnes, Daniel

    2016-10-01

    A novel plasma state, obtained by applying a helical voltage at the wall with a uniform axial magnetic field, is studied by means of zero-pressure resistive MHD simulations in a periodic cylinder. The radial magnetic field at the wall is taken to be zero. For a small helical electrode voltage, the helical perturbation in the plasma is small and localized to the edge. Beyond a critical electrode voltage, there is a bifurcation to the newly discovered state, which is a single-helicity Ohmic equilibrium with the same helicity as the electrodes, i.e., the fields depend only on radius and mθ - nφ , where θ and φ = z / R are the poloidal and toroidal angles. For electrostatic driving with m = 1 , the mean magnetic field (m = n = 0) has field line safety factor q(r) equal to the pitch of the electrodes m / n = 1 / n except near the edge, where it monotonically increases an amount of order unity. The plasma is force-free in the interior. Near the edge, however, the current crosses the field lines to enter and exit through the helical electrodes. A large helical plasma flow related Pfirsch-Schlüter-like currents exist in this edge vicinity. Applications to current drive in tokamaks, as well as to straight plasmas with endcap electrodes are discussed.

  1. Palatal sinus elevation revisited: a technical note.

    PubMed

    Seemann, Rudolf; Wagner, Florian; Ewers, Rolf; Ulm, Christian

    2013-08-01

    The palatal sinus lift is a good choice for patients with scarred buccal soft tissue and those with poor wound healing such as smokers or diabetics or when visual side effects such as swelling must be concealed. We provide a surgical protocol for palatal sinus lifting without a vertical release incision. The incision is started in a slightly palatal aspect, at the distal end of the dental arch, and describes a curve laterally on the alveolar crest while running in a mesial direction. As a marginal incision, it can continue to the central incisor. Submucosal exposure will lift the gum and the greater palatine artery. After insertion of a tongue depressor, the sinus is opened on the palatal side, opposite the zygomaticoalveolar crest, using a rose bur or a piezotome. After sinus augmentation, the incision is easy to close, and the wound will heal smoothly.

  2. Cleft Lip and Palate (For Parents)

    MedlinePlus

    ... or more if they are having hearing problems. Dental Problems Children with a cleft lip and palate ... improve speech and breathing, overbites/underbites, and appearance. Dental and Orthodontic Treatment Maintaining healthy teeth and preventing ...

  3. SPring-8 twin helical undulator.

    PubMed

    Hara, T; Tanaka, T; Tanabe, T; Maréchal, X M; Kumagai, K; Kitamura, H

    1998-05-01

    There are several ways of producing circularly polarized light, such as using asymmetric devices, crossed undulators etc. The SPring-8 helical undulator introduces a simple way of producing both horizontal and vertical fields in one undulator. All the magnet arrays are arranged above and below the plane of the electron orbit, so there is no limitation of access from the sides of the undulator. For the SPring-8 BL25SU, two helical undulators will be installed in tandem, and the helicity of the polarization can be switched at up to 10 Hz using five kicker magnets.

  4. New interpretation of the palate of Pterosaurs.

    PubMed

    Osi, Attila; Prondvai, Edina; Frey, Eberhard; Pohl, Burkhardt

    2010-02-01

    On the basis of a new, three-dimensionally preserved specimen of the Early Jurassic pterosaur Dorygnathus banthensis we present a reinterpretation of the pterosaur palate. The hard palate is formed by the extensive palatal plate of the maxilla and not by the palatine as has been generally reconstructed. This palatal plate of the maxilla emarginates the choana rostrally and rostrolaterally as in other archosaurs and lepidosaurs. The longitudinally elongate and dorsoventrally flat palatine in Dorygnathus is an isolated bone caudal to the palatal plate of the maxilla and morphologically and topographically it resembles that of crocodilians and birds, respectively. The palatine separates the choana laterally from the suborbital fenestra demonstrating the homologous nature of the (primary) choana in all archosaurs and lepidosaurs. Our study indicates that in basal pterosaurs the pterygo-ectopterygoid fenestra existed caudal to the suborbital fenestra, which became confluent with the adductor chamber in pterodactyloids thereby increasing the relative size of the adductor chamber and hence the mass of the jaw adductors. The choana in basal pterosaurs was relatively small compared with the interpterygoid vacuity. With increasing rostroventral inclination of the quadrates in more derived pterosaurs, the interpterygoid vacuity was reduced considerably, whereas the choana increased in size. This exceptional Dorygnathus specimen also shows a hitherto unknown pair of fenestrae situated at the palatal contact of the premaxilla-maxilla and might represent the aperture for the vomeronasal organ.

  5. Palatal asymmetry during development: an anatomical study.

    PubMed

    Moreira, R S; Sgrott, E A; Stuker, H; Alonso, L G; Smith, R L

    2008-07-01

    The purpose of this study was to evaluate hard palate asymmetry during development. The palates of 248 dry skulls were photographed and evaluated digitally. The skulls were divided into seven groups: fetus, newborn, infant, child, adolescent, adult, and aged. Linear measures were obtained from great palatine foramen (GPF) to incisive fossa (INC) and to posterior nasal spine (PNS). Angular measures were obtained from the former landmarks plus the point on sutures intersection between maxillary and palatine bones. Asymmetry was evaluated intra and intergroups. All skulls showed some degree of right-left asymmetry in the hard palate. Regardless of hard palate asymmetry, none of the right-left side differences was statistically significant. For the intergroups assessment, none of the asymmetry index means were statistically different. The posterior part of palate (PNS x GPF) measures was more asymmetric than the anterior part (INC x GPF), showing, respectively, 4.6% and 2.8% of mean asymmetry index. Angular measures showed a more symmetric behavior than the linear ones. Hard palate asymmetry occurs even in the absence of masticatory function, showing that this feature begins early in fetal life and persists through development.

  6. Developmental Epigenetics of the Murine Secondary Palate

    PubMed Central

    Seelan, Ratnam S.; Mukhopadhyay, Partha; Pisano, M. Michele; Greene, Robert M.

    2012-01-01

    Orofacial clefts occur with a frequency of 1 to 2 per 1000 live births. Cleft palate, which accounts for 30% of orofacial clefts, is caused by the failure of the secondary palatal processes—medially directed, oral projections of the paired embryonic maxillary processes—to fuse. Both gene mutations and environmental effects contribute to the complex etiology of this disorder. Although much progress has been made in identifying genes whose mutations are associated with cleft palate, little is known about the mechanisms by which the environment adversely influences gene expression during secondary palate development. An increasing body of evidence, however, implicates epigenetic processes as playing a role in adversely influencing orofacial development. Epigenetics refers to inherited changes in phenotype or gene expression caused by processes other than changes in the underlying DNA sequence. Such processes include, but are not limited to, DNA methylation, microRNA effects, and histone modifications that alter chromatin conformation. In this review, we describe our current understanding of the possible role epigenetics may play during development of the secondary palate. Specifically, we present the salient features of the embryonic palatal methylome and profile the expression of numerous microRNAs that regulate protein-encoding genes crucial to normal orofacial ontogeny. PMID:23744964

  7. Dynamic volume CT: the next revolution in clinical CT

    NASA Astrophysics Data System (ADS)

    Boedeker, Kirsten; Mather, Rich

    2008-08-01

    The need for table motion in multi-detector CT causes image volumes acquired for whole organ motion and perfusion studies to lack temporal uniformity. The next revolution in clinical CT, dynamic volume CT, mitigates this limitation by providing the ability to acquire an entire organ with isotropic resolution in a single gantry rotation with no table movement. The first dynamic volume CT scanner has recently been introduced and comprises 320 detector rows of 0.5mm channel thickness, covering 16cm of anatomy in one rotation of 0.35sec. This scanner offers many advancements in terms of temporal uniformity, reconstruction, and radiation dose. This system significantly reduces motion artifact and eliminates contrast phase differences within the volume. Because this scanner does not require helical acquisition for volumetric imaging, it delivers significantly less dose for applications such as CT coronary angiography exams as well as reduced dose in most other applications. Furthermore, by eliminating table motion, the need for complex interpolation methods that can distort cardiac images is removed. Image quality is not sacrificed compared with standard 64-row CT scanners, as demonstrated via low contrast, resolution, and accuracy measurements presented in this work. By capturing the entire brain in one rotation, brain perfusion, bone subtraction, and quantitative perfusion analysis are now possible with a single low dose exam. Dynamic volume CT offers to change the way medicine approaches stroke patients, myocardial perfusion studies, and imaging of other moving body parts such as the lung and joints.

  8. Tunable Helical Origami

    NASA Astrophysics Data System (ADS)

    Chen, Zi; Dai, Eric; Zheng, Huang

    2014-03-01

    Origami, the Japanese art of paper folding, is traditionally viewed as an amusing pastime and medium of artistic expression. However, in recent years, origami has begun to inspire innovations in science and engineering. For example, K. Miura led the study of a paper folding pattern in regards to deployment of solar panels to outer space, resulting in more efficient packing and unpacking of the solar panels into tightly constrained spaces. In this work, we study the geometric and mechanical properties of a twisting origami pattern. The pattern created by the fold exhibits several interesting properties, including rigid foldibility, and finely tunable helical coiling, with control over pitch, radius, and handedness of the helix. In addition, the pattern closely mimics the twist buckling patterns shown by thin materials, for example, a mobius strip. In our work, we relate the six parameters of the twisting origami pattern to generate a fully tunable graphical model of the fold. In addition, we demonstrate that the morphogenesis of such folding pattern can be modeled through finite element analysis. We hope our research into the diagonal fold brings insight into the potential scientific and engineering applications of origami and spark further research into how the traditional paper art can be applied as a simple, inexpensive model for complex problems.

  9. Twist Helicity in Classical Vortices

    NASA Astrophysics Data System (ADS)

    Scheeler, Martin W.; Kedia, Hridesh; Kleckner, Dustin; Irvine, William T. M.

    2015-11-01

    Recent experimental work has demonstrated that a partial measure of fluid Helicity (the sum of linking and writhing of vortex tubes) is conserved even as those vortices undergo topology changing reconnections. Measuring the total Helicity, however, requires additional information about how the vortex lines are locally twisted inside the vortex core. To bridge this gap, we have developed a novel technique for experimentally measuring twist Helicity. Using this method, we are able to measure the production and eventual decay of twist for a variety of vortex evolutions. Remarkably, we observe twist dynamics capable of conserving total Helicity even in the presence of rapidly changing writhe. This work was supported by the NSF MRSEC shared facilities at the University of Chicago (DMR-0820054) and an NSF CAREER award (DMR-1351506). W.T.M.I. further acknowledges support from the A.P. Sloan Foundation and the Packard Foundation.

  10. Helicity multiplexed broadband metasurface holograms

    PubMed Central

    Wen, Dandan; Yue, Fuyong; Li, Guixin; Zheng, Guoxing; Chan, Kinlong; Chen, Shumei; Chen, Ming; Li, King Fai; Wong, Polis Wing Han; Cheah, Kok Wai; Yue Bun Pun, Edwin; Zhang, Shuang; Chen, Xianzhong

    2015-01-01

    Metasurfaces are engineered interfaces that contain a thin layer of plasmonic or dielectric nanostructures capable of manipulating light in a desirable manner. Advances in metasurfaces have led to various practical applications ranging from lensing to holography. Metasurface holograms that can be switched by the polarization state of incident light have been demonstrated for achieving polarization multiplexed functionalities. However, practical application of these devices has been limited by their capability for achieving high efficiency and high image quality. Here we experimentally demonstrate a helicity multiplexed metasurface hologram with high efficiency and good image fidelity over a broad range of frequencies. The metasurface hologram features the combination of two sets of hologram patterns operating with opposite incident helicities. Two symmetrically distributed off-axis images are interchangeable by controlling the helicity of the input light. The demonstrated helicity multiplexed metasurface hologram with its high performance opens avenues for future applications with functionality switchable optical devices. PMID:26354497

  11. Magnetic Helicity and Planetary Dynamos

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2012-01-01

    A model planetary dynamo based on the Boussinesq approximation along with homogeneous boundary conditions is considered. A statistical theory describing a large-scale MHD dynamo is found, in which magnetic helicity is the critical parameter

  12. Data Correction for Gantry-tilted Local CT.

    PubMed

    Liang, Hongzhu; Zhang, Cishen; Yan, Ming; Zhou, Jiayin

    2005-01-01

    Gantry-tilted helical multi-slice computed tomography (CT) refers to the helical scanning CT system equipped with multi-row detector operating at some gantry tilting angle. Its purpose is to avoid the area which is vulnerable to the X-ray radiation. The local tomography is to reduce the total radiation dose by only scanning the region of interest for image reconstruction. In this paper we consider the scanning scheme, and incorporate the local tomography technique with the gantry-tilted helical multi-slice CT. The image degradation problem caused by gantry tilting is studied, and a new error correction method is proposed to deal with this problem in the local CT. Computer simulation shows that the proposed method can enhance the local imaging performance in terms of image sharpness and artifacts reduction.

  13. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  14. omega-Helices in proteins.

    PubMed

    Enkhbayar, Purevjav; Boldgiv, Bazartseren; Matsushima, Norio

    2010-05-01

    A modification of the alpha-helix, termed the omega-helix, has four residues in one turn of a helix. We searched the omega-helix in proteins by the HELFIT program which determines the helical parameters-pitch, residues per turn, radius, and handedness-and p = rmsd/(N - 1)(1/2) estimating helical regularity, where "rmsd" is the root mean square deviation from the best fit helix and "N" is helix length. A total of 1,496 regular alpha-helices 6-9 residues long with p < or = 0.10 A were identified from 866 protein chains. The statistical analysis provides a strong evidence that the frequency distribution of helices versus n indicates the bimodality of typical alpha-helix and omega-helix. Sixty-two right handed omega-helices identified (7.2% of proteins) show non-planarity of the peptide groups. There is amino acid preference of Asp and Cys. These observations and analyses insist that the omega-helices occur really in proteins.

  15. The next large helical devices

    NASA Astrophysics Data System (ADS)

    Iiyoshi, Atsuo; Yamazaki, Kozo

    1995-06-01

    Helical systems have the strong advantage of inherent steady-state operation for fusion reactors. Two large helical devices with fully superconducting coil systems are presently under design and construction. One is the LHD (Large Helical Device) [Fusion Technol. 17, 169 (1990)] with major radius=3.9 m and magnetic field=3-4 T, that is under construction during 1990-1997 at NIFS (National Institute for Fusion Science), Nagoya/Toki, Japan; it features continuous helical coils and a clean helical divertor focusing on edge configuration optimization. The other one in the W7-X (Wendelstein 7-X) [in Plasma Physics and Controlled Fusion Nuclear Research, 1990, (International Atomic Energy Agency, Vienna, 1991), Vol. 3, p. 525] with major radius=5.5 m and magnetic field=3 T, that is under review at IPP (Max-Planck Institute for Plasma Physics), Garching, Germany; it has adopted a modular coil system after elaborate optimization studies. These two programs are complementary in promoting world helical fusion research and in extending the understanding of toroidal plasmas through comparisons with large tokamaks.

  16. The Korean Prevocalic Palatal Glide: A Comparison with the Russian Glide and Palatalization.

    PubMed

    Suh, Yunju; Hwang, Jiwon

    2016-01-01

    Phonetic studies of the Korean prevocalic glides have often suggested that they are shorter in duration than those of languages like English, and lack a prolonged steady state. In addition, the formant frequencies of the Korean labiovelar glide are reported to be greatly influenced by the following vowel. In this study the Korean prevocalic palatal glide is investigated vis-à-vis the two phonologically similar configurations of another language - the glide /j/ and the secondary palatalization of Russian, with regard to the inherent duration of the glide component, F2 trajectory, vowel-to-glide coarticulation and glide-to-vowel coarticulation. It is revealed that the Korean palatal glide is closer to the Russian palatalization in duration and F2 trajectory, indicating a lack of steady state, and to the Russian segmental glide in the vowel-to-glide coarticulation degree. When the glide-to-vowel coarticulation is considered, the Korean palatal glide is distinguished from both Russian categories. The results suggest that both the Korean palatal glide and the Russian palatalization involve significant articulatory overlap, the former with the vowel and the latter with the consonant. Phonological implications of such a difference in coarticulation pattern are discussed, as well as the comparison between the Korean labiovelar and palatal glides.

  17. Palatogenesis: morphogenetic and molecular mechanisms of secondary palate development

    PubMed Central

    Bush, Jeffrey O.; Jiang, Rulang

    2012-01-01

    Mammalian palatogenesis is a highly regulated morphogenetic process during which the embryonic primary and secondary palatal shelves develop as outgrowths from the medial nasal and maxillary prominences, respectively, remodel and fuse to form the intact roof of the oral cavity. The complexity of control of palatogenesis is reflected by the common occurrence of cleft palate in humans. Although the embryology of the palate has long been studied, the past decade has brought substantial new knowledge of the genetic control of secondary palate development. Here, we review major advances in the understanding of the morphogenetic and molecular mechanisms controlling palatal shelf growth, elevation, adhesion and fusion, and palatal bone formation. PMID:22186724

  18. Palatal changes after lip surgery in different types of cleft lip and palate.

    PubMed

    Kramer, G J; Hoeksma, J B; Prahl-Andersen, B

    1994-09-01

    This study concerns palatal development during 6 months following primary lip closure. The sample consisted of 75 children with different forms of cleft lip and palate and 51 noncleft children. The palate was measured at 3 months of age, just before lip surgery, after surgery at 6 months, and again at 9 months of age. The results showed that lip closure has a strong effect in the anterior alveolar region. This effect was restricted to 3 months after surgery. The changes in complete clefts were more explicit than in incomplete cleft forms. Furthermore, the data showed that arch depth reduction due to lip surgery was compensated for by continued anteroposterior palatal growth. Early orthopedics appeared to prevent major palatal collapse immediately after lip surgery. Finally simultaneous closure of the alveolar cleft at the nasal side resulted in continued reduction of anterior cleft width.

  19. Morphology of the auditory tube and palatal muscles in a case of bilateral cleft palate.

    PubMed

    Arnold, W H; Nohadani, N; Koch, K H H

    2005-03-01

    There is an increased incidence of otitis media in children with cleft palate, which may be related to the pathology of the auditory tube and palatal muscles. In the present study, the head of a human on term born fetus with bilateral palatal cleft was serially sectioned and the anatomy of the auditory tube and palatal muscles were studied by computer-aided three-dimensional reconstruction. The results showed a nearly horizontal course of the auditory tube. The tensor veli palatini muscle had a bony attachment on either side. The levator veli palatini muscle also showed an abnormal course. This abnormal course may result in obstruction of the auditory tube during contraction. These pathological findings may explain the higher frequency of otitis media in children with cleft palate.

  20. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  1. Influence of different palate repair protocols on facial growth in unilateral complete cleft lip and palate.

    PubMed

    Xu, Xue; Kwon, Hyuk-Jae; Shi, Bing; Zheng, Qian; Yin, Heng; Li, Chenghao

    2015-01-01

    To address the question of whether one- or two-stage palatal treatment protocol has fewer detrimental effects on craniofacial growth in patients aged 5 years with unilateral complete cleft lip and palate. Forty patients with non-syndromic unilateral complete cleft lip and palate (UCCLPs) who had received primary cleft lip repair at age 6-12 months and cleft palate repair at age 18-30 months were selected in this study. Eighteen UCCLP patients who received two-stage palate repair were selected as group 1, and 22 UCCLP patients who received one-stage palate repair were selected as group 2. The control group consisted of 20 patients with unilateral incomplete cleft lip (UICL patients) whose age and gender matched with UCCLP patients. A one-sample Kolmogorov-Smirnov test was used to analyze the nature of data distribution. Bonferroni test and Kruskal-Wallis H tests were used for multiple comparisons. Both case groups showed reduced maxillary sagittal length (ANS-PMP, A-PM, p < 0.05) and retrusion of the maxilla (S-Ptm, p < 0.05), A point and ANS point (Ba-N-A, Ba-N-ANS, p < 0.05). Patients treated with two-stage palate repair had a reduced posterior maxillary vertical height (R-PMP, p < 0.05). Our results indicated that maxillary sagittal length and position could be perturbed by both one- and two-stage palate repair. Vomer flap repair inhibited maxilla vertical growth. Delayed hard palate repair showed less detrimental effects on maxillary growth compared to early hard palate repair in UCCLP patients aged 5 years. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  2. Dental materials for cleft palate repair.

    PubMed

    Sharif, Faiza; Ur Rehman, Ihtesham; Muhammad, Nawshad; MacNeil, Sheila

    2016-04-01

    Numerous bone and soft tissue grafting techniques are followed to repair cleft of lip and palate (CLP) defects. In addition to the gold standard surgical interventions involving the use of autogenous grafts, various allogenic and xenogenic graft materials are available for bone regeneration. In an attempt to discover minimally invasive and cost effective treatments for cleft repair, an exceptional growth in synthetic biomedical graft materials have occurred. This study gives an overview of the use of dental materials to repair cleft of lip and palate (CLP). The eligibility criteria for this review were case studies, clinical trials and retrospective studies on the use of various types of dental materials in surgical repair of cleft palate defects. Any data available on the surgical interventions to repair alveolar or palatal cleft, with natural or synthetic graft materials was included in this review. Those datasets with long term clinical follow-up results were referred to as particularly relevant. The results provide encouraging evidence in favor of dental and other related biomedical materials to fill the gaps in clefts of lip and palate. The review presents the various bones and soft tissue replacement strategies currently used, tested or explored for the repair of cleft defects. There was little available data on the use of synthetic materials in cleft repair which was a limitation of this study. In conclusion although clinical trials on the use of synthetic materials are currently underway the uses of autologous implants are the preferred treatment methods to date.

  3. Obstructive sleep apnea: a palatable treatment option?

    PubMed

    Allison, C

    2007-01-01

    (1) The Pillar(R) Palatal Implant System consists of three polyester threads that are permanently implanted in the palate (the roof of the mouth) to reduce airway obstruction in individuals with mild to moderate obstructive sleep apnea (OSA) and snoring. (2) Three small, non-randomized uncontrolled trials reported a moderate reduction in the number of breathing interruptions during sleep, three to six months following palatal implant insertion. Statistically significant improvements in daytime sleepiness and snoring intensity were also reported. (3) The minimally invasive surgical procedure causes mild, transient discomfort. A potential complication is partial extrusion of the implant, requiring removal and replacement. (4) Currently, there is insufficient published evidence to determine whether palatal implants are an effective treatment option for patients with mild to moderate OSA due to palatal obstruction. (5) Larger, randomized controlled studies are needed to determine the long-term safety and efficacy of the implants in a more diverse patient population, including those who are obese or those with comorbid medical conditions. Comparisons with existing treatments for OSA are also needed.

  4. Selective control for helical microswimmers

    NASA Astrophysics Data System (ADS)

    Katsamba, Panayiota; Lauga, Eric

    2015-11-01

    One of the greatest aspirations for artificial microswimmers is their application in non-invasive medicine. For any practical use, adequate mechanisms enabling control of multiple artificial swimmers is of paramount importance. Here we propose a multi-helical, freely-jointed motor as a novel selective control mechanism. We show that the nonlinear step-out behavior of a magnetized helix driven by a rotating magnetic field can be exploited, when used in conjunction with other helices, to obtain a velocity profile that is non-negligible only within a chosen interval of operating frequencies. Specifically, the force balance between the competing opposite-handed helices is tuned to give no net motion at low frequencies while in the middle frequency range, the swimming velocity increases monotonically with the driving frequency if two opposite helices are used, thereby allowing speed adjustment by varying the driving frequency. We illustrate this idea in detail on a two-helix system, and demonstrate how to generalize to N helices, both numerically and theoretically. We finish by explaining how to solve the inverse problem and design an artificial swimmer with an arbitrarily-complex velocity vs. frequency relationship.

  5. Flexible helical-axis stellarator

    DOEpatents

    Harris, Jeffrey H.; Hender, Timothy C.; Carreras, Benjamin A.; Cantrell, Jack L.; Morris, Robert N.

    1988-01-01

    An 1=1 helical winding which spirals about a conventional planar, circular central conductor of a helical-axis stellarator adds a significant degree of flexibility by making it possible to control the rotational transform profile and shear of the magnetic fields confining the plasma in a helical-axis stellarator. The toroidal central conductor links a plurality of toroidal field coils which are separately disposed to follow a helical path around the central conductor in phase with the helical path of the 1=1 winding. This coil configuration produces bean-shaped magnetic flux surfaces which rotate around the central circular conductor in the same manner as the toroidal field generating coils. The additional 1=1 winding provides flexible control of the magnetic field generated by the central conductor to prevent the formation of low-order resonances in the rotational transform profile which can produce break-up of the equilibrium magnetic surfaces. Further, this additional winding can deepen the magnetic well which together with the flexible control provides increased stability.

  6. Dental Care for a Child with Cleft Lip and Palate

    MedlinePlus

    ... to replace missing teeth. Oral appliances called “speech bulbs” or “palatal lifts” may help close the nose ... assure the best possible result. When a speech bulb or palatal lift is developed, the prosthodontist usually ...

  7. Two-stage palate repair with delayed hard palate closure is related to favorable maxillary growth in unilateral cleft lip and palate.

    PubMed

    Liao, Yu-Fang; Yang, I-Ying; Wang, Ruby; Yun, Claudia; Huang, Chiung-Shing

    2010-05-01

    Two-stage palate repair with delayed hard palate closure is generally advocated because it allows the best possible postoperative maxillary growth. Nevertheless, in the literature, it has been questioned whether maxillary growth is better following use of this protocol. The authors therefore aimed to investigate whether stage of palate repair, one-stage versus two-stage, had a significant effect on facial growth in patients with unilateral cleft lip and palate. Seventy-two patients with nonsyndromic complete unilateral cleft lip and palate operated on by two different protocols for palate repair, one-stage versus two-stage with delayed hard palate closure, and their 223 cephalometric radiographs were available in the retrospective longitudinal study. Clinical notes were reviewed to record treatment histories. Cephalometry was used to determine facial morphology and growth rate. Generalized estimating equations analysis was performed to assess the relationship between (1) facial morphology at age 20 and (2) facial growth rate, and the stage of palate repair. Stage of palate repair had a significant effect on the length and protrusion of the maxilla and the anteroposterior jaw relation at age 20, but not on their growth rates. The data suggest that in patients with unilateral cleft lip and palate, two-stage palate repair has a smaller adverse effect than one-stage palate repair on the growth of the maxilla. This stage effect is on the anteroposterior development of the maxilla and is attributable to the development being undisturbed before closure of the hard palate (i.e., hard palate repair timing specific).

  8. Cleft palate only: current concepts

    PubMed Central

    TETTAMANTI, L.; AVANTAGGIATO, A.; NARDONE, M.; SILVESTRE-RANGIL, J.; TAGLIABUE, A.

    2017-01-01

    SUMMARY Cleft palate only (CPO) is one of the most common congenital malformations worldwide. The etiopathogenesis of CPO is not completely understood. Environmental factors, such as smoking, alcohol consumption, intake of drugs during pregnancy, advanced paternal age, have been demonstrated to be a risk of CPO, but conflicting results have also been published. Insufficient intake of folic acid during the pregnancy has been suggested to increase the risk for CPO. The demonstrated risk for siblings and the higher risk for monozygotic twins suggest a genetic etiopathogenesis for CPO. In some cases of CPO a prevalent mode of inheritance has been reported, but oligogenic models with reduced penetrance, and the risk related to environmental factors have also been proved. One of the first manifestations associated with CPO is difficulty with feeding. Aerophagia is a problem in these infants with CPO and requires more frequent burping and slower feeding. The inability to generate intraoral breath pressure due to nasal air emission in CPO children frequently manifests as articulation difficulties, particularly consonant weakness, and unintelligible speech. Hearing disorders are prevalent among individuals with CPO, as a result of chronic otitis media with effusion due to eustachian tube dysfunction. A multidisciplinary team is essential to manage the many aspects of CPO. In treating CPO, the reconstructive surgeon works in cooperation with otolaryngologists, dentists and orthodontists, speech pathologists, audiologists, geneticists, psychiatrists, maxillofacial surgeons, social workers, and prosthodontists. CPO can be considered a genetically complex disease, but new knowledge and new therapeutic approaches have greatly improved the quality of life of these children. Prenatal diagnosis is an important step in the treatment of this disease. PMID:28757935

  9. Cleft palate only: current concepts.

    PubMed

    Tettamanti, L; Avantaggiato, A; Nardone, M; Silvestre-Rangil, J; Tagliabue, A

    2017-01-01

    Cleft palate only (CPO) is one of the most common congenital malformations worldwide. The etiopathogenesis of CPO is not completely understood. Environmental factors, such as smoking, alcohol consumption, intake of drugs during pregnancy, advanced paternal age, have been demonstrated to be a risk of CPO, but conflicting results have also been published. Insufficient intake of folic acid during the pregnancy has been suggested to increase the risk for CPO. The demonstrated risk for siblings and the higher risk for monozygotic twins suggest a genetic etiopathogenesis for CPO. In some cases of CPO a prevalent mode of inheritance has been reported, but oligogenic models with reduced penetrance, and the risk related to environmental factors have also been proved. One of the first manifestations associated with CPO is difficulty with feeding. Aerophagia is a problem in these infants with CPO and requires more frequent burping and slower feeding. The inability to generate intraoral breath pressure due to nasal air emission in CPO children frequently manifests as articulation difficulties, particularly consonant weakness, and unintelligible speech. Hearing disorders are prevalent among individuals with CPO, as a result of chronic otitis media with effusion due to eustachian tube dysfunction. A multidisciplinary team is essential to manage the many aspects of CPO. In treating CPO, the reconstructive surgeon works in cooperation with otolaryngologists, dentists and orthodontists, speech pathologists, audiologists, geneticists, psychiatrists, maxillofacial surgeons, social workers, and prosthodontists. CPO can be considered a genetically complex disease, but new knowledge and new therapeutic approaches have greatly improved the quality of life of these children. Prenatal diagnosis is an important step in the treatment of this disease.

  10. Sagittal maxillary growth pattern in unilateral cleft lip and palate patients with unrepaired cleft palate.

    PubMed

    Chen, Zhen-Qi; Wu, Jun; Chen, Rong-Jing

    2012-03-01

    The objective of the study was to examine the sagittal maxillary growth pattern during the mixed and permanent dentition in unilateral cleft lip and palate (UCLP) patients with unrepaired cleft palate. A total of 30 nonsyndromic UCLP patients with unrepaired cleft palate were included, 15 of whom were in mixed dentition and 15 in permanent dentition.Cephalograms were analyzed and compared in the patients with UCLP who have operatively undergone repair with both the lip and palate as well as normal subjects. The UCLP patients with unrepaired cleft palate in mixed dentition showed decreased anterior-posterior length of the maxilla. The UCLP patients with unrepaired cleft palate in permanent dentition demonstrated an almost normal maxillary growth. The operated-on patients both in mixed and permanent dentitions showed maxillary retrusion as well as decreased maxillary length. There appears that there may be the potential normal maxillary growth in UCLP patients, and early surgical repair of the cleft palate may affect sagittal maxillary growth pattern in patients with cleft.

  11. Use of Postoperative Palatal Obturator After Total Palatal Reconstruction With Radial Forearm Fasciocutaneous Free Flap.

    PubMed

    Jeong, Euicheol C; Jung, Young Ho; Shin, Jin-yong

    2015-07-01

    A 67-year-old-male patient visited our hospital for a mass on the soft palate of approximately 5.0 × 6.0  cm in size. He was diagnosed with adenoid cystic carcinoma and reconstruction after total palate resection was planned. After ablative surgery, a radial forearm free flap procedure was successfully performed to cover the hard and soft palates. However, wound disruption occurred twice during the postoperative period. When a palate defect is reconstructed using a soft tissue free flap, flap drooping by gravitation and the flap itself can generate irregularity in the lower contour of the palate and, in the long-term, insufficiencies of velopharyngeal function, speech, and mastication. To complement such functional and aesthetic problems caused by flap drooping, conventional prosthetics and new operative techniques have been discussed. However, overcoming wound disruption caused by flap drooping in the acute postoperative period has not been discussed. In this case, the temporary use of a palatal obturator during the postoperative period was beneficial after soft tissue reconstruction of the palate.

  12. Lipoma of the Palate: An Uncommon Finding

    PubMed Central

    Volpato, Luiz Evaristo Ricci; Vasconcelos, Artur Cunha; Lambert, Nayane Assis; de Souza Castro, Paulo Henrique; Aburad, Arlindo; Borges, Alvaro Henrique

    2016-01-01

    Background: Lipoma is a benign neoplasm originated from adipose cells circumscribed by connective tissue. This neoplasm represents about 1% to 4.4% of all oral benign tumors and it is rarely located in the palate area. Objective: This case reports the occurrence of an oral lipoma in the hard palate of a 57-year-old woman and discusses its etiology and treatment. Case Report: The treatment consisted in the total resection of the lesion and laser therapy. The patient is being followed up for forty three months with no signs of recurrence. Conclusion: Lipoma in hard palate is a rare entity that may be associated with endocrine factors and local inflammation. PMID:28077968

  13. Generalized helicity and Beltrami fields

    SciTech Connect

    Buniy, Roman V.; Kephart, Thomas W.

    2014-05-15

    We propose covariant and non-abelian generalizations of the magnetic helicity and Beltrami equation. The gauge invariance, variational principle, conserved current, energy–momentum tensor and choice of boundary conditions elucidate the subject. In particular, we prove that any extremal of the Yang–Mills action functional 1/4 ∫{sub Ω}trF{sub μν}F{sup μν}d{sup 4}x subject to the local constraint ε{sup μναβ}trF{sub μν}F{sub αβ}=0 satisfies the covariant non-abelian Beltrami equation. -- Highlights: •We introduce the covariant non-abelian helicity and Beltrami equation. •The Yang–Mills action and instanton term constraint lead to the Beltrami equation. •Solutions of the Beltrami equation conserve helicity.

  14. Contribution of Underlying Connective Tissue Cells to Taste Buds in Mouse Tongue and Soft Palate.

    PubMed

    Boggs, Kristin; Venkatesan, Nandakumar; Mederacke, Ingmar; Komatsu, Yoshihiro; Stice, Steve; Schwabe, Robert F; Mistretta, Charlotte M; Mishina, Yuji; Liu, Hong-Xiang

    2016-01-01

    Taste buds, the sensory organs for taste, have been described as arising solely from the surrounding epithelium, which is in distinction from other sensory receptors that are known to originate from neural precursors, i.e., neural ectoderm that includes neural crest (NC). Our previous study suggested a potential contribution of NC derived cells to early immature fungiform taste buds in late embryonic (E18.5) and young postnatal (P1-10) mice. In the present study we demonstrated the contribution of the underlying connective tissue (CT) to mature taste buds in mouse tongue and soft palate. Three independent mouse models were used for fate mapping of NC and NC derived connective tissue cells: (1) P0-Cre/R26-tdTomato (RFP) to label NC, NC derived Schwann cells and derivatives; (2) Dermo1-Cre/RFP to label mesenchymal cells and derivatives; and (3) Vimentin-CreER/mGFP to label Vimentin-expressing CT cells and derivatives upon tamoxifen treatment. Both P0-Cre/RFP and Dermo1-Cre/RFP labeled cells were abundant in mature taste buds in lingual taste papillae and soft palate, but not in the surrounding epithelial cells. Concurrently, labeled cells were extensively distributed in the underlying CT. RFP signals were seen in the majority of taste buds and all three types (I, II, III) of differentiated taste bud cells, with the neuronal-like type III cells labeled at a greater proportion. Further, Vimentin-CreER labeled cells were found in the taste buds of 3-month-old mice whereas Vimentin immunoreactivity was only seen in the CT. Taken together, our data demonstrate a previously unrecognized origin of taste bud cells from the underlying CT, a conceptually new finding in our knowledge of taste bud cell derivation, i.e., from both the surrounding epithelium and the underlying CT that is primarily derived from NC.

  15. Contribution of Underlying Connective Tissue Cells to Taste Buds in Mouse Tongue and Soft Palate

    PubMed Central

    Mederacke, Ingmar; Komatsu, Yoshihiro; Stice, Steve; Schwabe, Robert F.; Mistretta, Charlotte M.; Mishina, Yuji; Liu, Hong-Xiang

    2016-01-01

    Taste buds, the sensory organs for taste, have been described as arising solely from the surrounding epithelium, which is in distinction from other sensory receptors that are known to originate from neural precursors, i.e., neural ectoderm that includes neural crest (NC). Our previous study suggested a potential contribution of NC derived cells to early immature fungiform taste buds in late embryonic (E18.5) and young postnatal (P1-10) mice. In the present study we demonstrated the contribution of the underlying connective tissue (CT) to mature taste buds in mouse tongue and soft palate. Three independent mouse models were used for fate mapping of NC and NC derived connective tissue cells: (1) P0-Cre/R26-tdTomato (RFP) to label NC, NC derived Schwann cells and derivatives; (2) Dermo1-Cre/RFP to label mesenchymal cells and derivatives; and (3) Vimentin-CreER/mGFP to label Vimentin-expressing CT cells and derivatives upon tamoxifen treatment. Both P0-Cre/RFP and Dermo1-Cre/RFP labeled cells were abundant in mature taste buds in lingual taste papillae and soft palate, but not in the surrounding epithelial cells. Concurrently, labeled cells were extensively distributed in the underlying CT. RFP signals were seen in the majority of taste buds and all three types (I, II, III) of differentiated taste bud cells, with the neuronal-like type III cells labeled at a greater proportion. Further, Vimentin-CreER labeled cells were found in the taste buds of 3-month-old mice whereas Vimentin immunoreactivity was only seen in the CT. Taken together, our data demonstrate a previously unrecognized origin of taste bud cells from the underlying CT, a conceptually new finding in our knowledge of taste bud cell derivation, i.e., from both the surrounding epithelium and the underlying CT that is primarily derived from NC. PMID:26741369

  16. An EPG Study of Palatal Consonants in Two Australian Languages

    ERIC Educational Resources Information Center

    Tabain, Marija; Fletcher, Janet; Butcher, Andrew

    2011-01-01

    This study presents EPG (electro-palatographic) data on (alveo-)palatal consonants from two Australian languages, Arrernte and Warlpiri. (Alveo-)palatal consonants are phonemic for stop, lateral and nasal manners of articulation in both languages, and are laminal articulations. However, in Arrernte, these lamino-(alveo-)palatals contrast with…

  17. L2 Perception of Spanish Palatal Variants across Different Tasks

    ERIC Educational Resources Information Center

    Shea, Christine; Renaud, Jeffrey

    2014-01-01

    While considerable dialectal variation exists, almost all varieties of Spanish exhibit some sort of alternation in terms of the palatal obstruent segments. Typically, the palatal affricate [??] tends to occur in word onset following a pause and in specific linear phonotactic environments. The palatal fricative [?] tends to occur in syllable onset…

  18. Acoustic Analysis on the Palatalized Vowels of Modern Mongolian

    ERIC Educational Resources Information Center

    Bulgantamir, Sangidkhorloo

    2015-01-01

    In Modern Mongolian the palatalized vowels [a?, ??, ?? ] before palatalized consonants are considered as phoneme allophones according to the most scholars. Nevertheless theses palatalized vowels have the distinctive features what could be proved by the minimal pairs and nowadays this question is open and not profoundly studied. The purpose of this…

  19. L2 Perception of Spanish Palatal Variants across Different Tasks

    ERIC Educational Resources Information Center

    Shea, Christine; Renaud, Jeffrey

    2014-01-01

    While considerable dialectal variation exists, almost all varieties of Spanish exhibit some sort of alternation in terms of the palatal obstruent segments. Typically, the palatal affricate [??] tends to occur in word onset following a pause and in specific linear phonotactic environments. The palatal fricative [?] tends to occur in syllable onset…

  20. Cleft palate in a male water buffalo calf.

    PubMed

    Mazaheri, Y; Ranjbar, R; Ghadiri, A R; Afsahr, F Saberi; Nejad, S Goorani; Mahabady, M Khaksary; Afrough, M; Karampoor, R; Tavakoli, A

    2007-12-15

    Congenital palatal defects are common in animals but there is only one report of water buffalo has been recorded in Iran. One died male water buffalo calf was examined after hysterotomy operation. At necropsy findings, brachygnathia, palate cleft and small lungs were diagnosed. It is the second report of water buffalo cleft palate in Iran.

  1. Palatability of twelve species of anuran larvae in eastern Texas

    Treesearch

    Cory K. Adams; Daniel Saenz; Richard N. Conner

    2011-01-01

    We tested the palatability of 12 species of anuran larvae that occur in eastern Texas using four common predators. Palatability was determined by offering larvae to predators and recording the behavior of the predator. We also tested for ontogenetic shifts in palatability in twelve species of anuran larvae. Incilius nebulifer, Anaxyrus woodhousii, Lithobates...

  2. [Cleft lip and palate in Campeche Mayas].

    PubMed

    Weiss, K M; Georges, E; Levy, B; Aguirre, A; Portilla, R J; Gaitán, C L; Leyva, E; Rodríguez, T

    1988-07-01

    It has been suggested that among American Indians, as in some genetically-related Asiatic ethnic groups, incidence of cleft lip and/or cleft palate is higher than among people of Caucasian extraction. Such hypothesis, plus growing demand for services observed at a center for the surgery of cleft lip and cleft palate in Campeche state, led the authors to undertake research among the Maya residents of that region. However, neither careful review of case histories nor field research performed in several Indian communities could confirm the hypothesis of a higher incidence among this ethnic community.

  3. Cleft palate: players, pathways, and pursuits

    PubMed Central

    Murray, Jeffrey C.; Schutte, Brian C.

    2004-01-01

    Cleft lip and palate is a common human birth defect, and its causes are being dissected through studies of human populations and through the use of animal models. Mouse models in particular have made a substantial contribution to our understanding of the gene pathways involved in palate development and the nature of signaling molecules that act in a tissue-specific manner at critical stages of embryogenesis. Related work has provided further support for investigating the role of common environmental triggers as causal covariates. PMID:15199400

  4. Myoepithelial carcinoma of palate: case report.

    PubMed

    Thayumanavan, Balakrishnan; Vani, Nandimandalam Venkata

    2014-01-01

    Myoepithelial carcinoma is an uncommon malignant salivary gland neoplasm with a predilection for parotid gland. However, its occurrence in minor salivary glands is considerably less with only 28 cases being reported in the literature. We report a case of myoepithelial carcinoma of palate in a 50-year-old woman. Computed tomography and magnetic resonance imaging revealed an extensive lesion in the palate. Microscopically, the tumor exhibited a wide spectrum of cytomorphologic features that overlap with other salivary gland tumors. Immunohistochemistry served as an adjunct in the diagnosis of the lesion. Clinical, radiographic, and histopathologic correlation along with immunohistochemical profile enabled to arrive at a diagnosis of myoepithelial carcinoma.

  5. Cleft Lip and Palate Repair: Our Experience.

    PubMed

    Gatti, Gian Luca; Freda, Nicola; Giacomina, Alessandro; Montemagni, Marina; Sisti, Andrea

    2017-09-12

    Cleft lip and palate is the most frequent congenital craniofacial deformity. In this article, the authors describe their experience with cleft lip and palate repair. Data regarding patients presenting with primary diagnosis of cleft lip and/or palate, between 2009 and 2015, were reviewed. Details including demographics, type of cleft, presence of known risk factors, surgical details, and follow-up visits were collected. Documented complications were reported. Caregivers' satisfaction was assessed with a survey. The survey used to assess satisfaction with cleft-related features was based on the cleft evaluation profile (CEP). In addition, 4 assessors used visual analog scale (VAS) to assess the aesthetic satisfaction. Seven hundred fifty-two patients with primary diagnosis of cleft lip and/or palate underwent surgical correction at "S. Chiara" Hospital, 432 (57.45%) male and 320 (42.55%) female. The most common cleft types in our study were incomplete cleft palate (152 patients) and left unilateral complete cleft lip and palate (152 patients). Associated syndromes were found in 46 patients (6.12%). Cleft lip was repaired using a modified Tennison-Randall technique when the defect was unilateral, whereas a modified Mulliken technique was used for bilateral cleft lip. Cleft palate was repaired using the Bardach technique or Von Langenbeck technique at 5 to 6 months of age. Cleft lip and palate was repaired in several surgical steps. In total, complications were reported in 81 of 752 patients (14.16%). Average fathers' satisfaction score assessed using CEP was 4.5 (lip), 4.8 (nose), 4.7 (teeth), 4.8 (bite), 4.2 (breathing), 4.6 (profile). Average mothers' satisfaction score assessed using CEP was 4.3 (lip), 4.6 (nose), 4.4 (teeth), 4.5 (bite), 4.1 (breathing), 4.4 (profile). Average level of aesthetic satisfaction, assessed using VAS, was 8.7 (fathers), 8.1 (mothers), 7.9 (lay person), and 8.0 (senior cleft surgeon). The multidisciplinary management of children with

  6. Speech evaluation for patients with cleft palate.

    PubMed

    Kummer, Ann W

    2014-04-01

    Children with cleft palate are at risk for speech problems, particularly those caused by velopharyngeal insufficiency. There may be an additional risk of speech problems caused by malocclusion. This article describes the speech evaluation for children with cleft palate and how the results of the evaluation are used to make treatment decisions. Instrumental procedures that provide objective data regarding the function of the velopharyngeal valve, and the 2 most common methods of velopharyngeal imaging, are also described. Because many readers are not familiar with phonetic symbols for speech phonemes, Standard English letters are used for clarity.

  7. Acquired and isolated asymmetrical palatal palsy.

    PubMed

    Cuvellier, J C; Cuisset, J M; Nuyts, J P; Vallée, L

    1998-12-01

    Benign acquired and isolated asymmetrical palatal palsy is a rare condition in childhood. We report on three cases. Typical features include: sudden onset, abnormality of the palatal components of speech (rhinolalia), nasal escape of fluids from the ipsilateral nostril. It is supposed to be caused by viral infection, but attempts at viral isolation were unsuccessful. Complete spontaneous recovery is usual, taking a few weeks. Our paper seems to be the first report of magnetic resonance imaging of the brain in this condition. It did not disclose any abnormalities in the 2 cases in which it was performed.

  8. Palatal obturators in patients after maxillectomy

    PubMed Central

    CARDELLI, P.; BIGELLI, E.; VERTUCCI, V.; BALESTRA, F.; MONTANI, M.; DE CARLI, S.; ARCURI, C.

    2014-01-01

    SUMMARY Prosthodontic management of palatal defects is fundamental to improve patient’s life undergoing to a maxillary surgical treatment. A lot of maxillary defects are a direct consequence of surgical treatment of malformations, neoplasms or trauma. The obturators are prosthesis used to close palatal defects after maxillectomy, to restore masticatory function and to improve speech. The primary goals of the obturator prosthesis are to preserve the remaining teeth and tissue and to provide comfort, function, and aesthetics to the patients. Different materials and retention methods are a characteristic of new types of obturators. PMID:25992263

  9. Helical axis stellarator equilibrium model

    SciTech Connect

    Koniges, A.E.; Johnson, J.L.

    1985-02-01

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift.

  10. On steady kinematic helical dynamos

    NASA Astrophysics Data System (ADS)

    Eltayeb, I. A.; Loper, D. E.

    The equations governing steady kinematic helical dynamos are studied, using the formalism of Benton (1979), when the flow has no radial component (in cylindrical coordinates). It is shown that all solutions must decay exponentially to zero at large distances, s, from the axis of the helix. When the flow depends on s only it is shown that a necessary condition for dynamo action is that the flow possesses components along both the primary and secondary helices. It is also found that periodic motion of one mode along the primary helix cannot support dynamo action even if the field is composed of mean and periodic parts.

  11. Brownian motion of helical flagella.

    PubMed

    Hoshikawa, H; Saito, N

    1979-07-01

    We develops a theory of the Brownian motion of a rigid helical object such as bacterial flagella. The statistical properties of the random forces acting on the helical object are discussed and the coefficients of the correlations of the random forces are determined. The averages , and are also calculated where z and theta are the position along and angle around the helix axis respectively. Although the theory is limited to short time interval, direct comparison with experiment is possible by using the recently developed cinematography technique.

  12. 20 percent lower lung cancer mortality with low-dose CT vs chest X-ray

    Cancer.gov

    Scientists have found a 20 percent reduction in deaths from lung cancer among current or former heavy smokers who were screened with low-dose helical computed tomography (CT) versus those screened by chest X-ray.

  13. The Fetal Cleft palate: V. Elucidation of the Mechanism of Palatal Clefting in the Congenital Caprine Model

    USDA-ARS?s Scientific Manuscript database

    Maternal ingestion of Nicotiana glauca from gestation days 32 through 41 results in a high incidence of cleft palate in Spanish goats. This caprine cleft palate model was used to evaluate the temporal sequence of palatal shelf fusion throughout the period of cleft induction with the poisonous plant...

  14. Maxillary Arch Dimensions and Spectral Characteristics of Children with Cleft Lip and Palate Who Produce Middorsum Palatal Stops

    ERIC Educational Resources Information Center

    Zajac, David J.; Cevidanes, Lucia; Shah, Sonam; Haley, Katarina L.

    2012-01-01

    Purpose: The purpose of this study was twofold: (a) to determine maxillary arch dimensions of children with repaired cleft lip and palate (CLP) who produced middorsum palatal stops and (b) to describe some spectral characteristics of middorsum palatal stops. Method: Maxillary arch width, length, and height dimensions and first spectral moments of…

  15. Maxillary Arch Dimensions and Spectral Characteristics of Children with Cleft Lip and Palate Who Produce Middorsum Palatal Stops

    ERIC Educational Resources Information Center

    Zajac, David J.; Cevidanes, Lucia; Shah, Sonam; Haley, Katarina L.

    2012-01-01

    Purpose: The purpose of this study was twofold: (a) to determine maxillary arch dimensions of children with repaired cleft lip and palate (CLP) who produced middorsum palatal stops and (b) to describe some spectral characteristics of middorsum palatal stops. Method: Maxillary arch width, length, and height dimensions and first spectral moments of…

  16. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

  17. Analysis of Fetal Palate to Assist Pre-natal Ultrasound

    PubMed Central

    Ravindranath, Yogitha; Ravindranath, Roopa

    2016-01-01

    Introduction Cleft palate is one of the major facial congenital malformation in newborns. Pre-natal detection of this malformation is limited to detection of clefting of hard palate but isolated soft palate clefting still remains challenge for sonologists. As Indian literature is limited present study was attempted to provide dimensions and position of fetal palate by digitized images. Aim To study dimensions, position and differences in parameters between second and third trimester fetuses. Materials and Methods Median sagittal section of 32 formalin fixed fetuses was selected from the Department of Anatomy, St John’s Medical College, Bangalore, Karnataka, India. Anatomical landmarks-The Nasion (N), Sellaturcica (S), Anterior Nasal Spine (ANS), Posterior Nasal Spine (PNS), tip of Uvula (U) were marked on sections. Length of hard palate (from ANS to PNS), Length of soft palate (from PNS to U), Hard palate/soft palate angle was defined. The anterior position of soft palate and its posterior position in relation to anterior cranial base were marked as N-S-PNS and N-S-U angle, respectively. The measurements were acquired directly from the digitized images using ImageJ software. Statistical analysis was done using SPSS 16. Results The mean values of ANS-PNS and PNS-U were 23.59±3.69mm and 14.39±2.70mm, respectively. The mean values of hard palate/soft palate angle, N-S-PNS and N-S-U angle were 144.720±11.11,51.150±9.09 and 93.370±9.58, respectively. Significant difference was noted between trimesters for length of hard and soft palate but not for palatal angles. Conclusion During Pre-natal assessment of cleft palate, it is important for sonologist to keep in mind that the dimensions of palate proportionately increased in last two trimesters while the position remains constant. PMID:27891327

  18. Better understanding of tubular helical buckling

    SciTech Connect

    Wu, J.

    1996-09-01

    Tubular buckling is a significant problem within the oil industry. Although it has been studied for many years, methods to analyze tubular helical buckling continues to appear in the literature. Several criteria have been derived and presented leading to confusion in understanding and correctly predicting tubular helical buckling. The prediction of tubular helical buckling is complicated by the fact that the tubular is confined within the wellbore. The tubular initially buckles sinusoidally, and then changes into the shape of a helix (helical buckling) as the axial load increases. Different approaches in modeling the helical buckling process and the use of energy methods resulted in those different helical buckling criteria. Helical buckling criteria proposed in the literature, as well as their derivations are discussed in this paper, to help better understand and effectively predict tubular helical buckling in engineering operations.

  19. The transport of relative canonical helicity

    SciTech Connect

    You, S.

    2012-09-15

    The evolution of relative canonical helicity is examined in the two-fluid magnetohydrodynamic formalism. Canonical helicity is defined here as the helicity of the plasma species' canonical momentum. The species' canonical helicity are coupled together and can be converted from one into the other while the total gauge-invariant relative canonical helicity remains globally invariant. The conversion is driven by enthalpy differences at a surface common to ion and electron canonical flux tubes. The model provides an explanation for why the threshold for bifurcation in counter-helicity merging depends on the size parameter. The size parameter determines whether magnetic helicity annihilation channels enthalpy into the magnetic flux tube or into the vorticity flow tube components of the canonical flux tube. The transport of relative canonical helicity constrains the interaction between plasma flows and magnetic fields, and provides a more general framework for driving flows and currents from enthalpy or inductive boundary conditions.

  20. Note: Helical nanobelt force sensors

    SciTech Connect

    Hwang, G.; Hashimoto, H.

    2012-12-15

    We present the fabrication and characterization of helical nanobelt force sensors. These self-sensing force sensors are based on the giant piezoresistivity of helical nanobelts. The three-dimensional helical nanobelts are self-formed from 27 nm-thick n-type InGaAs/GaAs bilayers using rolled-up techniques, and assembled onto electrodes on a micropipette using nanorobotic manipulations. The helical nanobelt force sensors can be calibrated using a calibrated atomic force microscope cantilever system under scanning electron microscope. Thanks to their giant piezoresistance coefficient (515 Multiplication-Sign 10{sup -10} Pa{sup -1}), low stiffness (0.03125 N/m), large-displacement capability ({approx}10 {mu}m), and good fatigue resistance, they are well suited to function as stand-alone, compact ({approx}20 {mu}m without the plug-in support), light ({approx}5 g including the plug-in support), versatile and large range ({approx}{mu}N) and high resolution ({approx}nN) force sensors.

  1. Note: Helical nanobelt force sensors

    NASA Astrophysics Data System (ADS)

    Hwang, G.; Hashimoto, H.

    2012-12-01

    We present the fabrication and characterization of helical nanobelt force sensors. These self-sensing force sensors are based on the giant piezoresistivity of helical nanobelts. The three-dimensional helical nanobelts are self-formed from 27 nm-thick n-type InGaAs/GaAs bilayers using rolled-up techniques, and assembled onto electrodes on a micropipette using nanorobotic manipulations. The helical nanobelt force sensors can be calibrated using a calibrated atomic force microscope cantilever system under scanning electron microscope. Thanks to their giant piezoresistance coefficient (515 × 10-10 Pa-1), low stiffness (0.03125 N/m), large-displacement capability (˜10 μm), and good fatigue resistance, they are well suited to function as stand-alone, compact (˜20 μm without the plug-in support), light (˜5 g including the plug-in support), versatile and large range (˜μN) and high resolution (˜nN) force sensors.

  2. Helical symmetry in linear systems

    SciTech Connect

    Bicak, Jiri; Schmidt, Bernd G.

    2007-11-15

    We investigate properties of solutions of the scalar wave equation and Maxwell's equations on Minkowski space with helical symmetry. Existence of local and global solutions with this symmetry is demonstrated with and without sources. The asymptotic properties of the solutions are analyzed. We show that the Newman-Penrose retarded and advanced scalars exhibit specific symmetries and generalized peeling properties.

  3. Conservation of magnetic helicity during plasma relaxation

    SciTech Connect

    Ji, H.; Prager, S.C.; Sarff, J.S.

    1994-07-01

    Decay of the total magnetic helicity during the sawtooth relaxation in the MST Reversed-Field Pinch is much larger than the MHD prediction. However, the helicity decay (3--4%) is smaller than the magnetic energy decay (7--9%), modestly supportive of the helicity conservation hypothesis in Taylor`s relaxation theory. Enhanced fluctuation-induced helicity transport during the relaxation is observed.

  4. Investigation of Helical Pulse Forming Line

    NASA Astrophysics Data System (ADS)

    Liu, Zhenxiang; Zhang, Jiande

    2006-09-01

    To investigate the feasibility for a helical line to be used as a pulse forming line (PFL), the transmission characteristics of the helical transmission line is studied both theoretically and experimentally. The results indicate that it is feasible to employ a helical line as a long-pulse PFL, and the influence of its dispersion is negligible. Compared with a conventional coaxial PFL, the helical PFL with the same size can produce a longer pulse.

  5. Cleft lip and palate care in Romania.

    PubMed

    Martin, Vanessa

    2011-11-01

    Vanessa Martin travelled with a surgical team to Romania over a period of 12 years to support nurses and improve practice in the treatment of cleft lip and palate. She recounts her experiences and the changes that took place during that time.

  6. Parental Reactions to Cleft Palate Children.

    ERIC Educational Resources Information Center

    Vanpoelvoorde, Leah

    This literature review examines parental reactions following the birth of a cleft lip/palate child, focusing primarily on the mother's reactions. The research studies cited have explored such influences on maternal reactions as her feelings of lack of control over external forces and her feelings of guilt that the deformity was her fault. Delays…

  7. PALATAL DYSMORPHOGENESIS: QUANTITATIVE RT-PCR

    EPA Science Inventory

    ABSTRACT

    Palatal Dysmorphogenesis : Quantitative RT-PCR

    Gary A. Held and Barbara D. Abbott

    Reverse transcription PCR (RT-PCR) is a very sensitive method for detecting mRNA in tissue samples. However, as it is usually performed it is does not yield quantitativ...

  8. PALATAL DYSMORPHOGENESIS: QUANTITATIVE RT-PCR

    EPA Science Inventory

    ABSTRACT

    Palatal Dysmorphogenesis : Quantitative RT-PCR

    Gary A. Held and Barbara D. Abbott

    Reverse transcription PCR (RT-PCR) is a very sensitive method for detecting mRNA in tissue samples. However, as it is usually performed it is does not yield quantitativ...

  9. Parental Reactions to Cleft Palate Children.

    ERIC Educational Resources Information Center

    Vanpoelvoorde, Leah; Shaughnessy, Michael F.

    1991-01-01

    This paper reviews parents' emotional reactions following the birth of a cleft lip/palate child. It examines when parents were told of the deformity and discusses the duties of the speech-language pathologist and the psychologist in counseling the parents and the child. (Author/JDD)

  10. Parental Reactions to Cleft Palate Children.

    ERIC Educational Resources Information Center

    Vanpoelvoorde, Leah; Shaughnessy, Michael F.

    1991-01-01

    This paper reviews parents' emotional reactions following the birth of a cleft lip/palate child. It examines when parents were told of the deformity and discusses the duties of the speech-language pathologist and the psychologist in counseling the parents and the child. (Author/JDD)

  11. Palatability of Forage Chicory Cultivars for Goats

    USDA-ARS?s Scientific Manuscript database

    Sesquiterpene lactones (SL) in forage chicory (Cichorium intybus L.) may have anthelmintic activity against gastrointestinal parasites in sheep and goats, but have been implicated in poor palatability of forage. We used three levels of soil P fertilization to influence SL concentrations in three cu...

  12. [Repair of palatal fistulae in cleft patients].

    PubMed

    Bénateau, H; Traoré, H; Gilliot, B; Taupin, A; Ory, L; Guillou Jamard, M-R; Labbé, D; Compère, J-F

    2011-06-01

    Treatment of oronasal fistulae in cleft patients remains a surgical challenge because of its high failure rate. The authors report the results of an aggressive surgical technique using the total elevation of palatal mucoperiosteum, even for small fistulae. This approach was used on twelve consecutive patients, from five to 33 years of age, presenting with a Pittsburgh classification type IV palatal fistulae. The surgical procedure was total elevation of the hard palate mucoperiosteum starting from the dental sulcus combined with sealed double layer sutures. Clinical and photographical control was made at least 6 months after to detect a possible relapse. The success rate was 100%. No relapsing fistula was observed with follow-up ranging from 6 to 36 months. This technique allows wide exposure and safe closure of the nasal layer. It is simple and leaves no raw bone surface exposed and no additional scar. The authors think it can be used in all type IV fistulae less than 1cm wide. Several other surgical techniques have been described to close palatal fistulae: local turnover flaps, pedicled flaps from adjacent oral tissue, tongue flaps, tissue expansion, and even free flaps. Obturator prostheses have also been used. The technique we report, even if more aggressive, seems to be more reliable with fewer relapse and sequelae. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  13. The middle ear in cleft palate children pre and post palatal closure.

    PubMed Central

    Dhillon, R S

    1988-01-01

    A multicentre prospective trial was commenced in July 1984 to establish the incidence of otitis media with effusion (OME) in children born with a cleft of the palate. Additionally, the data recorded would allow an assessment of the effect of palatal closure on middle ear function. Prior to palatal closure, 97% of ears in a group of 50 patients had otitis media with effusion (OME). The insertion of a long-term ventilation tube provided a means of aeration of one ear with the non-ventilated ear acting as a control. Eighty percent of control ears had persistent OME during a 24-month follow-up period post palatal repair. It would seem that OME is universally present in children with a cleft palate prior to 4 months of age and this incidence is only marginally diminished by palatal surgery. The liaison between plastic surgical and ENT units should be even closer than before in order to manage these patients satisfactorily. PMID:3065499

  14. Hybrid helical snakes and rotators for RHIC

    SciTech Connect

    Courant, E.D.

    1995-06-13

    The spin rotators and Siberian snakes presently envisaged for RHIC utilize helical dipole magnets. The snakes and the rotators each consist of four helices, each with a full twist (360{degrees}) of the field. Here we investigate an alternate layout, namely combinations of helical and pure bending magnet, and show that this may have advantages.

  15. Enantiomeric differentiation by synthetic helical polymers.

    PubMed

    Yashima, Eiji; Iida, Hiroki; Okamoto, Yoshio

    2013-01-01

    Recent advances in the synthesis of helical polymers and their applications as chiral materials, in particular chiral stationary phases (CSPs), for high-performance liquid chromatography (HPLC) are reviewed with an emphasis on the key role of the helical conformations with one-handedness for the prominent chiral recognition of enantiomers. The historical background of artificial optically active helical polymers is also briefly described.

  16. Speech intelligibility after gingivectomy of excess palatal tissue.

    PubMed

    Balasundaram, Aruna; Vinayagavel, Mythreyi; Bandi, Dhathri Priya

    2014-07-01

    To appreciate any enhancement in speech following gingivectomy of enlarged anterior palatal gingiva. Periodontal literature has documented various conditions, pathophysiology, and treatment modalities of gingival enlargement. Relationship between gingival maladies and speech alteration has received scant attention. This case report describes on altered speech pattern enhancement secondary to the gingivectomy procedure. A systemically healthy 24-year- female patient reported with bilateral anterior gingival enlargement who was provisionally diagnosed as "gingival abscess with inflammatory enlargement" in relation to palatal aspect of the right maxillary canine to left maxillary canine. Bilateral gingivectomy procedure was performed by external bevel incision in relation to anterior palatal gingiva and a large wedge of epithelium and connective tissue was removed. Patient and her close acquaintances noticed a great improvement in her pronunciation and enunciation of sounds like "t", "d", "n", "l", "th", following removal of excess gingival palatal tissue and was also appreciated with visual analog scale score. Exploration of linguistic research documented the significance of tongue-palate contact during speech. Any excess gingival tissue in palatal region brings about disruption in speech by altering tongue-palate contact. Periodontal surgery like gingivectomy may improve disrupted phonetics. Excess gingival palatal tissue impedes on tongue-palate contact and interferes speech. Pronunciation of consonants like "t", "d", "n", "l", "th", are altered with anterior enlarged palatal gingiva. Excision of the enlarged palatal tissue results in improvement of speech.

  17. Helicity Within and Among Macromolecules

    NASA Astrophysics Data System (ADS)

    Green, Mark M.

    2004-03-01

    There are several classes of helical polymers and supramolecular arrays in which the left and right helical senses are of equal probability and as well in dynamic equilibrium. One example of this class of materials is a polymer first created at Dupont as a commercial fiber candidate almost fifty years ago but which did not rise to the level necessary for commercial use. The polymer, nylon 1, widely known as a polyisocyanate, did become a focal point of research for polymer physics because of its stiff archetypical wormlike nature. An array of research tools was able to elucidate the conformational characteristics of this polymer and therefore reveal in quantitative detail both the source of its stiffness and the limit to this characteristic. Further effort explored the nature of the expected lyotropic liquid crystal properties with similar success. As part of these studies, chiral experiments, which were introduced to determine how to favor one helical sense, played a key role. Statistical physical analysis of these chiral experiments first by Shneior Lifson for uniform chiral fields and later by Jonathan Selinger for quenched random chiral fields gave insight into the cooperative characteristics by which the chiral information influenced the helical senses in these polymers. These kinds of experiments finding parallels to the behavior of sergeants and soldiers and to majority rule were later applied widely in the literature offering insight into the cooperative nature of helical polymers and arrays in general. Moreover, the interplay between the character of the single chains and the liquid crystals that arise in concentrated solutions from the polyisocyanates yielded new kinds of information about the cholesteric state formed by lyotropic liquid crystals in general and even led to new phenomena connecting liquid crystal behavior to temperature.

  18. Palate Morphogenesis: Current Understanding and Future Directions

    PubMed Central

    Greene, Robert M.; Pisano, M. Michele

    2011-01-01

    In the past, most scientists conducted their inquiries of nature via inductivism, the patient accumulation of “pieces of information” in the pious hope that the sum of the parts would clarify the whole. Increasingly, modern biology employs the tools of bioinformatics and systems biology in attempts to reveal the “big picture.” Most successful laboratories engaged in the pursuit of the secrets of embryonic development, particularly those whose research focus is craniofacial development, pursue a middle road where research efforts embrace, rather than abandon, what some have called the “pedestrian” qualities of inductivism, while increasingly employing modern data mining technologies. The secondary palate has provided an excellent paradigm that has enabled examination of a wide variety of developmental processes. Examination of cellular signal transduction, as it directs embryogenesis, has proven exceptionally revealing with regard to clarification of the “facts” of palatal ontogeny—at least the facts as we currently understand them. Herein, we review the most basic fundamentals of orofacial embryology and discuss how functioning of TGFβ, BMP, Shh, and Wnt signal transduction pathways contributes to palatal morphogenesis. Our current understanding of palate medial edge epithelial differentiation is also examined. We conclude with a discussion of how the rapidly expanding field of epigenetics, particularly regulation of gene expression by miRNAs and DNA methylation, is critical to control of cell and tissue differentiation, and how examination of these epigenetic processes has already begun to provide a better understanding of, and greater appreciation for, the complexities of palatal morphogenesis. PMID:20544696

  19. Contractile Properties of Single Permeabilized Muscle Fibers from Congenital Cleft Palates and Normal Palates of Spanish Goats

    PubMed Central

    Hanes, Michael C.; Weinzweig, Jeffrey; Kuzon, William M.; Panter, Kip E.; Buchman, Steven R.; Faulkner, John A.; Yu, Deborah; Cederna, Paul S.; Larkin, Lisa M.

    2009-01-01

    Background Analysis of the composition of muscle fibers constituent to a cleft palate could provide significant insight into the cause of velopharyngeal inadequacy. The authors hypothesized that levator veli palatini muscle dysfunction inherent to cleft palates could affect the timing and outcome of cleft palate repair. Methods Single, permeabilized muscle fibers from levator veli palatini muscles of three normal (n = 19 fibers) and three chemically induced congenital cleft palates (n = 21 fibers) of 14-month-old goats were isolated, and contractile properties were evaluated. The maximum isometric force and rate constants of tension redevelopment (ktr) were measured, and the specific force and normalized power were calculated for each fiber. Results The ktr measures indicate that cleft fibers are predominantly fast-fatigable; normal fibers are slow fatigue-resistant: after a 10-minute isometric contraction, fibers from cleft palates had a loss of force 16 percent greater than that from normal palates (p = 0.0001). The cross-sectional areas of the fibers from cleft palates (2750 ± 209 μm2) were greater (p = 0.05) than those from normal palates (2226 ± 143 μm2). Specific forces did not differ between the two groups. Maximum normalized power of fibers from cleft palates (11.05 ± 1.82 W/l) was greater (p = 0.0001) than fibers from normal palates (1.60 ± 0.12 W/l). Conclusions There are clear physiologic differences in single muscle fibers from cleft palates and normal palates: cleft palate fibers are physiologically fast, have greater fatigability, and have greater power production. Detection of functional and/or fiber type differences in muscles of cleft palates may provide preoperative identification of a patient's susceptibility to velopharyngeal inadequacy and permit early surgical intervention to correct this clinical condition. PMID:17440342

  20. CT angiography in the abdomen: a pictorial review and update.

    PubMed

    Liu, Peter S; Platt, Joel F

    2014-02-01

    The development of multidetector CT technology and helical scanning techniques has revolutionized the use of CT for primary diagnostic evaluation of the abdominal vasculature, particularly the arterial system. CT angiography has numerous benefits relative to conventional catheter angiography, and has largely replaced catheter-based techniques in many clinical algorithms. This pictorial review and update will cover important technical principles related to modern CT angiography (including contrast delivery and dose considerations), discuss relevant anatomy and variants, and illustrate numerous arterial conditions related to the abdominal aorta and branch vessels.

  1. Magnetic Helicity Injection and Sigmoidal Coronal Loops

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tetsuya T.; Kusano, K.; Maeshiro, T.; Yokoyama, T.; Sakurai, T.

    2005-05-01

    We studied the relationship between magnetic helicity injection and the formation of sigmoidal loops. We analyzed seven active regions: three regions showed coronal loops similar to the potential field, and four regions showed the sigmoidal loops. The magnetic helicity injection rate was evaluated using the method proposed by Kusano et al. In order to compare the helicity of regions of various sizes, we defined the normalized helicity injection rate as the magnetic helicity injection rate divided by the magnetic flux squared. We found that the sigmoidal regions and nonsigmoidal regions have comparable normalized helicity injection rates. Next, we calculated the magnetic helicity content of the sigmoidal loops by using the magnetic flux tube model (Longcope & Welsch) and compared it with the magnetic helicity injected from around the footpoints of three sigmoidal loops. For two sigmoidal loops, it is found that these values are comparable. Another loop showed significant disagreement between helicity injection rate and its magnetic helicity content. Excluding this region on the basis of its complexity (perhaps multiple loops forming a sigmoidal loop), we can conclude that geometric twist of the sigmoidal loops is consistent with the magnetic helicity injected from around the footpoints of the sigmoidal loops.

  2. Predictive supracolloidal helices from patchy particles

    NASA Astrophysics Data System (ADS)

    Guo, Ruohai; Mao, Jian; Xie, Xu-Ming; Yan, Li-Tang

    2014-11-01

    A priori prediction of supracolloidal architectures from nanoparticle and colloidal assembly is a challenging goal in materials chemistry and physics. Despite intense research in this area, much less has been known about the predictive science of supracolloidal helices from designed building blocks. Therefore, developing conceptually new rules to construct supracolloidal architectures with predictive helicity is becoming an important and urgent task of great scientific interest. Here, inspired by biological helices, we show that the rational design of patchy arrangement and interaction can drive patchy particles to self-assemble into biomolecular mimetic supracolloidal helices. We further derive a facile design rule for encoding the target supracolloidal helices, thus opening the doors to the predictive science of these supracolloidal architectures. It is also found that kinetics and reaction pathway during the formation of supracolloidal helices offer a unique way to study supramolecular polymerization, and that well-controlled supracolloidal helices can exhibit tailorable circular dichroism effects at visible wavelengths.

  3. Predictive supracolloidal helices from patchy particles

    PubMed Central

    Guo, Ruohai; Mao, Jian; Xie, Xu-Ming; Yan, Li-Tang

    2014-01-01

    A priori prediction of supracolloidal architectures from nanoparticle and colloidal assembly is a challenging goal in materials chemistry and physics. Despite intense research in this area, much less has been known about the predictive science of supracolloidal helices from designed building blocks. Therefore, developing conceptually new rules to construct supracolloidal architectures with predictive helicity is becoming an important and urgent task of great scientific interest. Here, inspired by biological helices, we show that the rational design of patchy arrangement and interaction can drive patchy particles to self-assemble into biomolecular mimetic supracolloidal helices. We further derive a facile design rule for encoding the target supracolloidal helices, thus opening the doors to the predictive science of these supracolloidal architectures. It is also found that kinetics and reaction pathway during the formation of supracolloidal helices offer a unique way to study supramolecular polymerization, and that well-controlled supracolloidal helices can exhibit tailorable circular dichroism effects at visible wavelengths. PMID:25387544

  4. An experimental superconducting helical undulator

    SciTech Connect

    Caspi, S.; Taylor, C.

    1995-12-31

    Improvements in the technology of superconducting magnets for high energy physics and recent advancements in SC materials with the artificial pinning centers (APC){sup 2}, have made a bifilar helical SC device an attractive candidate for a single-pass free electron laser (FEL){sup 3}. Initial studies have suggested that a 6.5 mm inner diameter helical device, with a 27 mm period, can generate a central field of 2-2.5 Tesla. Additional studies have also suggested that with a stored energy of 300 J/m, such a device can be made self-protecting in the event of a quench. However, since the most critical area associated with high current density SC magnets is connected with quenching and training, a short experimental device will have to be built and tested. In this paper we discuss technical issues relevant to the construction of such a device, including a conceptual design, fields, and forces.

  5. Helical screw expander evaluation project

    NASA Technical Reports Server (NTRS)

    Mckay, R.

    1982-01-01

    A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  6. Adjustable phase planar helical undulator

    NASA Astrophysics Data System (ADS)

    Carr, Roger G.; Lidia, Steve

    1993-11-01

    We present here the design description of a new type of planar helical undulator, which we are constructing for the SPEAR storage ring at the Stanford Synchrotron Radiation Laboratory. It comprises four rows of pure permanent magnet blocks, one row in each quadrant about the axis defined by the electron beam. Rows may be translated longitudinally with respect to each other to change the helicity of the magnetic field they create at the position of the beam. They may also be translated longitudinally to vary the energy of the x-rays emitted, unlike designs where this function is performed by varying the gap between the rows. This work includes numerical calculations of the fields, electron trajectories, and x-ray spectra, including off-axis effects.

  7. Helical screw expander evaluation project

    NASA Astrophysics Data System (ADS)

    McKay, R.

    1982-03-01

    A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  8. A Comprehensive Study of Soft Palate Development in Mice

    PubMed Central

    Grimaldi, Alexandre; Parada, Carolina; Chai, Yang

    2015-01-01

    Cleft palate is one of the most common congenital birth defects. Tremendous efforts have been made over the last decades towards understanding hard palate development. However, little is known about soft palate morphogenesis and myogenesis. Finding an appropriate surgical repair to restore physiological functions of the soft palate in patients with cleft palate is a major challenge for surgeons, and complete restoration is not always achievable. Here, we first analyzed the morphology, orientation and attachments of the four muscles of the murine soft palate and found that they are very similar to their counterparts in humans, validating the use of mus musculus as a model for future studies. Our data suggests that muscle differentiation extends from the lateral region to the midline following palatal fusion. We also detected an epithelial seam in the fusing soft palatal shelves, consistent with the process of fusion of the posterior palatal shelves, followed by degradation of the epithelial remnants. Innervation and vascularization are present mainly in the oral side of the soft palate, complementing the differentiated muscles. Cell lineage tracing using Wnt1-Cre;Zsgreenfl/fl mice indicated that all the tendons and mesenchyme embedding the soft palate muscles are neural crest-derived. We propose that the posterior attachment of the soft palate to the pharyngeal wall is an interface between the neural crest- and mesoderm-derived mesenchyme in the craniofacial region, and thus can serve as a potential model for the study of boundaries during development. Taken together, our study provides a comprehensive view of the development and morphology of the murine soft palate and serves as a reference for further molecular analyses. PMID:26671681

  9. Tbx1 regulates oral epithelial adhesion and palatal development

    PubMed Central

    Funato, Noriko; Nakamura, Masataka; Richardson, James A.; Srivastava, Deepak; Yanagisawa, Hiromi

    2012-01-01

    Cleft palate, the most frequent congenital craniofacial birth defect, is a multifactorial condition induced by the interaction of genetic and environmental factors. In addition to complete cleft palate, a large number of human cases involve soft palate cleft and submucosal cleft palate. However, the etiology of these forms of cleft palate has not been well understood. T-box transcriptional factor (Tbx) family of transcriptional factors has distinct roles in a wide range of embryonic differentiation or response pathways. Here, we show that genetic disruption of Tbx1, a major candidate gene for the human congenital disorder 22q11.2 deletion syndrome (Velo-cardio-facial/DiGeorge syndrome), led to abnormal epithelial adhesion between the palate and mandible in mouse, resulting in various forms of cleft palate similar to human conditions. We found that hyperproliferative epithelium failed to undergo complete differentiation in Tbx1-null mice (Tbx1−/−). Inactivation of Tbx1 specifically in the keratinocyte lineage (Tbx1KCKO) resulted in an incomplete cleft palate confined to the anterior region of the palate. Interestingly, Tbx1 overexpression resulted in decreased cell growth and promoted cell-cycle arrest in MCF7 epithelial cells. These findings suggest that Tbx1 regulates the balance between proliferation and differentiation of keratinocytes and is essential for palatal fusion and oral mucosal differentiation. The impaired adhesion separation of the oral epithelium together with compromised palatal mesenchymal growth is an underlying cause for various forms of cleft palate phenotypes in Tbx1−/− mice. Our present study reveals new pathogenesis of incomplete and submucous cleft palate during mammalian palatogenesis. PMID:22371266

  10. A Comprehensive Study of Soft Palate Development in Mice.

    PubMed

    Grimaldi, Alexandre; Parada, Carolina; Chai, Yang

    2015-01-01

    Cleft palate is one of the most common congenital birth defects. Tremendous efforts have been made over the last decades towards understanding hard palate development. However, little is known about soft palate morphogenesis and myogenesis. Finding an appropriate surgical repair to restore physiological functions of the soft palate in patients with cleft palate is a major challenge for surgeons, and complete restoration is not always achievable. Here, we first analyzed the morphology, orientation and attachments of the four muscles of the murine soft palate and found that they are very similar to their counterparts in humans, validating the use of mus musculus as a model for future studies. Our data suggests that muscle differentiation extends from the lateral region to the midline following palatal fusion. We also detected an epithelial seam in the fusing soft palatal shelves, consistent with the process of fusion of the posterior palatal shelves, followed by degradation of the epithelial remnants. Innervation and vascularization are present mainly in the oral side of the soft palate, complementing the differentiated muscles. Cell lineage tracing using Wnt1-Cre;Zsgreenfl/fl mice indicated that all the tendons and mesenchyme embedding the soft palate muscles are neural crest-derived. We propose that the posterior attachment of the soft palate to the pharyngeal wall is an interface between the neural crest- and mesoderm-derived mesenchyme in the craniofacial region, and thus can serve as a potential model for the study of boundaries during development. Taken together, our study provides a comprehensive view of the development and morphology of the murine soft palate and serves as a reference for further molecular analyses.

  11. Hearing outcomes in patients with cleft lip/palate.

    PubMed

    Skuladottir, Hildur; Sivertsen, Ase; Assmus, Jorg; Remme, Asa Rommetveit; Dahlen, Marianne; Vindenes, Hallvard

    2015-03-01

    Objective : Children with cleft lip and palate or cleft palate only have a high incidence of conductive hearing loss from otitis media with effusion. Studies demonstrating longitudinal results are lacking. This study was undertaken to investigate long-term longitudinal hearing outcomes of children with cleft lip and/or cleft palate and cleft palate only. Design : Retrospective chart review. Setting : Clinical charts of patients born with cleft lip and palate or cleft palate only in 1985 to 1994 who were referred to the cleft team in Bergen, Norway. Study findings include 15 years of follow-up. Participants : The study population consisted of 317 children of whom 159 had nonsyndromic cleft lip and palate and 158 had nonsyndromic cleft palate. Main Outcome Measures : Pure tone average calculated from pure tone audiometry at ages 4, 6, and 15 years. Results : The median pure tone average significantly improved with increasing age. For the cleft lip and palate group, the median pure tone average at ages 4, 6, and 15 years was 16 dB hearing level (HL), 13 dB HL, and 9 dB HL, respectively (P ≤ .001). In the cleft palate group the median pure tone average at ages 4, 6, and 15 years was 15 dB HL, 12 dB HL, and 9 dB HL, respectively (P ≤ .001). There was no significant difference in the hearing levels between the two groups. Patients who had surgical closure of the palate at age 18 months had a significantly better pure tone average outcome at age 15 compared with patients who had surgery at 12 months. Conclusions : Hearing improves significantly from childhood to adolescence in patients with cleft lip and palate and cleft palate only.

  12. Topology of modified helical gears

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Zhang, J.; Handschuh, R. F.; Coy, J. J.

    1989-01-01

    The topology of several types of modified surfaces of helical gears is proposed. The modified surfaces allow absorption of a linear or almost linear function of transmission errors. These errors are caused by gear misalignment and an improvement of the contact of gear tooth surfaces. Principles and corresponding programs for computer aided simulation of meshing and contact of gears have been developed. The results of this investigation are illustrated with numerical examples.

  13. Topology of modified helical gears

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Zhang, J.; Handschuh, R. F.; Coy, J. J.

    1989-01-01

    The topology of several types of modified surfaces of helical gears is proposed. The modified surfaces allow absorption of a linear or almost linear function of transmission errors. These errors are caused by gear misalignment and an improvement of the contact of gear tooth surfaces. Principles and corresponding programs for computer aided simulation of meshing and contact of gears have been developed. The results of this investigation are illustrated with numerical examples.

  14. Emulsification-Induced Homohelicity in Racemic Helical Polymer for Preparing Optically Active Helical Polymer Nanoparticles.

    PubMed

    Zhao, Biao; Deng, Jinrui; Deng, Jianping

    2016-04-01

    Optically active nano- and microparticles have constituted a significant category of advanced functional materials. However, constructing optically active particles derived from synthetic helical polymers still remains as a big challenge. In the present study, it is attempted to induce a racemic helical polymer (containing right- and left-handed helices in equal amount) to prefer one predominant helicity in aqueous media by using emulsifier in the presence of chiral additive (emulsification process). Excitingly, the emulsification process promotes the racemic helical polymer to unify the helicity and directly provides optically active nanoparticles constructed by chirally helical polymer. A possible mechanism is proposed to explain the emulsification-induced homohelicity effect. The present study establishes a novel strategy for preparing chirally helical polymer-derived optically active nanoparticles based on racemic helical polymers.

  15. Helical Antimicrobial Sulfono- {gamma} -AApeptides

    SciTech Connect

    Li, Yaqiong; Wu, Haifan; Teng, Peng; Bai, Ge; Lin, Xiaoyang; Zuo, Xiaobing; Cao, Chuanhai; Cai, Jianfeng

    2015-06-11

    Host-defense peptides (HDPs) such as magainin 2 have emerged as potential therapeutic agents combating antibiotic resistance. Inspired by their structures and mechanism of action, herein we report the fi rst example of antimicrobial helical sulfono- γ - AApeptide foldamers. The lead molecule displays broad-spectrum and potent antimicrobial activity against multi-drug-resistant Gram- positive and Gram-negative bacterial pathogens. Time-kill studies and fl uorescence microscopy suggest that sulfono- γ -AApeptides eradicate bacteria by taking a mode of action analogous to that of HDPs. Clear structure - function relationships exist in the studied sequences. Longer sequences, presumably adopting more-de fi ned helical structures, are more potent than shorter ones. Interestingly, the sequence with less helical propensity in solution could be more selective than the stronger helix-forming sequences. Moreover, this class of antimicrobial agents are resistant to proteolytic degradation. These results may lead to the development of a new class of antimicrobial foldamers combating emerging antibiotic-resistant pathogens.

  16. Helicity comparison among three magnetographs

    NASA Astrophysics Data System (ADS)

    Xu, Haiqing; Gao, Yu; Zhang, Hongqi; Sakurai, T.; Pevtsov, A. A.; Sokoloff, D.

    We compare vector magnetograms of 228 active regions observed by Solar Magnetic Field Telescope (SMFT) at Huairou (HR) Solar Observing Station and the Solar Flare Telescope (SFT) at Mitaka (MTK) of the National Astronomical Observatory of Japan from 1992 to 2005 and 55 active regions observed by SFT and Haleakala Stokes Polarimeter (HSP) at Mees Solar Observatory, University of Hawaii from 1997 to 2000. Two helicity parameters, current helicity density hc and αff coefficient of linear force free field are calculated. From this comparison we conclude: (1) the mean azimuthal angle differences of transverse fields between HR and MTK data are systematic smaller than that between MTK and Mees data; (2) there are 83.8% of hc and 78.1% of αff for 228 active regions observed at HR and MTK agree in sign, and the Pearson linear correlation coefficient between these two data sets is 0.72 for hc and 0.56 for αff. There are 61.8% of hc and 58.2% of αff for 55 active regions observed at MTK and Mees agree in sign, and the Pearson linear correlation coefficient between these two data sets is 0.34 for hc and 0.31 for αff; (3) there is a basic agreement on time variation of helicity parameters in active regions observed at HR, Mees, and MTK.

  17. Helically twisted photonic crystal fibres.

    PubMed

    Russell, P St J; Beravat, R; Wong, G K L

    2017-02-28

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic 'space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of 'numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Authors.

  18. Helically twisted photonic crystal fibres

    PubMed Central

    Beravat, R.; Wong, G. K. L.

    2017-01-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic ‘space’, cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of ‘numerical experiments’ based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069771

  19. Helically twisted photonic crystal fibres

    NASA Astrophysics Data System (ADS)

    Russell, P. St. J.; Beravat, R.; Wong, G. K. L.

    2017-02-01

    Recent theoretical and experimental work on helically twisted photonic crystal fibres (PCFs) is reviewed. Helical Bloch theory is introduced, including a new formalism based on the tight-binding approximation. It is used to explore and explain a variety of unusual effects that appear in a range of different twisted PCFs, including fibres with a single core and fibres with N cores arranged in a ring around the fibre axis. We discuss a new kind of birefringence that causes the propagation constants of left- and right-spinning optical vortices to be non-degenerate for the same order of orbital angular momentum (OAM). Topological effects, arising from the twisted periodic `space', cause light to spiral around the fibre axis, with fascinating consequences, including the appearance of dips in the transmission spectrum and low loss guidance in coreless PCF. Discussing twisted fibres with a single off-axis core, we report that optical activity in a PCF is opposite in sign to that seen in a step-index fibre. Fabrication techniques are briefly described and emerging applications reviewed. The analytical results of helical Bloch theory are verified by an extensive series of `numerical experiments' based on finite-element solutions of Maxwell's equations in a helicoidal frame. This article is part of the themed issue 'Optical orbital angular momentum'.

  20. CT Enterography

    MedlinePlus

    ... during the procedure. Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the ...

  1. Flap Necrosis after Palatoplasty in Patients with Cleft Palate

    PubMed Central

    Rossell-Perry, Percy

    2015-01-01

    Palatal necrosis after palatoplasty in patients with cleft palate is a rare but significant problem encountered by any cleft surgeon. Few studies have addressed this disastrous complication and the prevalence of this problem remains unknown. Failure of a palatal flap may be attributed to different factors like kinking or section of the pedicle, anatomical variations, tension, vascular thrombosis, type of cleft, used surgical technique, surgeon's experience, infection, and malnutrition. Palatal flap necrosis can be prevented through identification of the risk factors and a careful surgical planning should be done before any palatoplasty. Management of severe fistulas observed as a consequence of palatal flap necrosis is a big challenge for any cleft surgeon. Different techniques as facial artery flaps, tongue flaps, and microvascular flaps have been described with this purpose. This review article discusses the current status of this serious complication in patients with cleft palate. PMID:26273624

  2. Nonsyndromic palate Synechia with floor of mouth

    PubMed Central

    Naidoo, Sharan; Bütow, Kurt W.

    2015-01-01

    To discuss the embryological basis, sequela and management of intraoral synechia, and to report on the incidence of this condition at a facial cleft deformity clinic (FCDC), with specific attention to two rare cases of mucosal bands involving the floor of the mouth and palate. Review of the literature and a retrospective analysis of FCDC and case report of two cases. During the period of 30 years (1983–2013), the FCDC - University of Pretoria has managed in excess of 4000 cases. A review of the clinic statistics revealed only six cases in which intraoral synechiae occurred. The rarity of this condition at the FCDC is in keeping with the rare incidence in the international literature. Four syndromic cases were identified. Three cases were cleft palate lateral synechia syndrome, and one was an orofacial digital syndrome. Two nonsyndromic cases were identified, and both cases involved the floor of the mouth and palate. The attending physicians and surgeons should be aware of the most appropriate timing for management of this condition, in order to avoid unwanted sequelae. Supportive care should be provided, and emergency airway protocol should be available for all cases. A differential diagnosis should be considered which includes syndromic conditions. PMID:26389045

  3. 22q11.2 deletion detected by endoscopic observation of pharyngeal pulsations in a child with submucous cleft palate and persistent velopharyngeal insufficiency.

    PubMed

    Ysunza, Antonio; Chaiyasate, Kongkrit; Micale, Mark A; McBrien, M Melissa; Bloom, David A; Gibson, Donald P; Weinhouse, Elliott

    2014-10-01

    22q11.2 microdeletion syndrome (22q11.2DS) is the most common syndrome associated with cleft palate and velopharyngeal insufficiency (VPI). Over 180 clinical features have been described. Most common features include: cardiac malformations, cleft palate, velopharyngeal insufficiency, characteristic facial features, hypotonia, behavioral disorders, and musculoskeletal disorders among several other fenotipical features. A case of 22q11.2DS confirmed by cytogenomic analysis is presented with review of the literature. Main clinical features were a submucous cleft palate (SMCP) with persistent VPI after palatoplasty, an ectopic left internal carotid artery and a prominent aortic root. VPI was corrected with a pharyngeal flap, tailored according to findings of videonasopharyngoscopy, videofluoroscopy and neck CT scan with contrast. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Parental satisfaction in Ugandan children with cleft lip and palate following synchronous lip and palatal repair.

    PubMed

    Luyten, Anke; D'haeseleer, Evelien; Budolfsen, Dorte; Hodges, Andrew; Galiwango, George; Vermeersch, Hubert; Van Lierde, Kristiane

    2013-01-01

    The purpose of the present case control study was to assess parental satisfaction with speech and facial appearance in Ugandan children with complete unilateral or bilateral cleft lip and palate (CLP), who underwent a synchronous lip and palatal closure. The results are compared with an age- and gender-matched control group. The experimental group consisted of the parents or guardians of 44 Ugandan patients (21 males, 23 females) with complete unilateral or bilateral CLP (mean age: 3;1 years). The control group included the foster mothers of 44 orphan children matched by age and gender (mean age: 3;7 years). A survey based on the Cleft Evaluation Profile was used to assess the perceived satisfaction for individual features related to cleft care. Overall high levels of satisfaction were observed in the experimental group for all features (range: 56-100%). No significant differences could be established regarding age, gender, age of lip and palatal closure, cleft type or maternal vs. paternal judgments. In participants who were dissatisfied with the appearance of the lip, the time period between the cleft closure and the survey was significantly larger compared with satisfied participants. Furthermore, significantly lower levels of satisfaction were observed in the cleft group for speech and the appearance of the teeth and the nose compared with the control group. Satisfaction with speech and facial appearance in Ugandan children with cleft lip and/or palate is important since normal esthetics and speech predominantly determine the children's social acceptance in the Ugandan society. As a result of reading this manuscript, the reader will be able to explain the attitudes of parents toward the surgical repair of their children's cleft lip and palate. As a result of reading this manuscript, the reader will be able to identify differences in parental attitudes toward synchronous lip and palate repair. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Psychogenic palatal tremor may be underrecognized: reappraisal of a large series of cases.

    PubMed

    Stamelou, Maria; Saifee, Tabish A; Edwards, Mark J; Bhatia, Kailash P

    2012-08-01

    Palatal tremor is characterized by rhythmic movements of the soft palate and can be essential or symptomatic. Some patients can have palatal movements as a special skill or due to palatal tics. Psychogenic palatal tremor is recognized but rarely reported in the literature. We retrospectively evaluated all patients with palatal tremor seen in our center over a period of 10 years. Of 17 patients with palatal tremor, we identified 10 patients with isolated palatal tremor. In 70% of those the diagnosis of psychogenic palatal tremor could be made. Of the remainder, 2 had palatal tics and 1 essential palatal tremor. We suggest that psychogenic palatal tremor may be underrecognized and propose that targeted clinical examination of positive signs for psychogenic movement disorders in these patients is essential. The correct identification of such patients has important clinical and scientific implications. Copyright © 2012 Movement Disorder Society.

  6. A Glance at Methods for Cleft Palate Repair

    PubMed Central

    Tavakolinejad, Sima; Ebrahimzadeh Bidskan, Alireza; Ashraf, Hami; Hamidi Alamdari, Daryoush

    2014-01-01

    Context: Cleft palate is the second most common birth defect and is considered as a challenge for pediatric plastic surgeons. There is still a general lack of a standard protocol and patients often require multiple surgical interventions during their lifetime along with disappointing results. Evidence Acquisition: PubMed search was undertaken using search terms including 'cleft palate repair', 'palatal cleft closure', 'cleft palate + stem cells', 'cleft palate + plasma rich platelet', 'cleft palate + scaffold', 'palatal tissue engineering', and 'bone tissue engineering'. The found articles were included if they defined a therapeutic strategy and/or assessed a new technique. Results: We reported a summary of the key-points concerning cleft palate development, the genes involving this defect, current therapeutic strategies, recently novel aspects, and future advances in treatments for easy and fast understanding of the concepts, rather than a systematic review. In addition, the results were integrated with our recent experience. Conclusions: Tissue engineering may open a new window in cleft palate reconstruction. Stem cells and growth factors play key roles in this field. PMID:25593724

  7. Shaping helical electrospun filaments: a review.

    PubMed

    Silva, P E S; Vistulo de Abreu, F; Godinho, M H

    2017-10-04

    Nature abounds with helical filaments designed for specific tasks. For instance, some plants use tendrils to coil and attach to the surroundings, while Spiroplasma, a helical bacterium, moves by inverting the helical handedness along the filament axis. Therefore, developing methods to shape filaments on demand to exhibit a diversity of physical properties and shapes could be of interest to many fields, such as the textile industry, biomedicine or nanotechnology. Electrospinning is a simple and versatile technique that allows the production of micro and nanofibres with many different helical shapes. In this work, we review the different electrospinning procedures that can be used to obtain helical shapes similar to those found in natural materials. These techniques also demonstrate that the creation of helical shapes at the micro/nanoscale is not limited by the chirality of the building blocks at the molecular level, a finding which opens new horizons on filament shaping.

  8. A periodicity analysis of transmembrane helices.

    PubMed

    Leonov, Hadas; Arkin, Isaiah T

    2005-06-01

    Transmembrane helices and the helical bundles which they form are the major building blocks of membrane proteins. Since helices are characterized by a given periodicity, it is possible to search for patterns of traits which typify one side of the helix and not the other (e.g. amphipathic helices contain a polar and apolar sides). Using Fourier transformation we have analyzed solved membrane protein structures as well as sequences of membrane proteins from the Swiss-Prot database. The traits searched included aromaticity, volume and ionization. While a number of motifs were already recognized in the literature, many were not. One particular example involved helix VII of lactose permease which contains seven aromatic residues on six helical turns. Similarly six glycine residues in four consecutive helical turns were identified as forming a motif in the chloride channel. A tabulation of all the findings is presented as well as a possible rationalization of the function of the motif.

  9. Helicity fluctuations in incompressible turbulent flows

    NASA Technical Reports Server (NTRS)

    Rogers, Michael M.; Moin, Parviz

    1987-01-01

    Results from direct numerical simulations of several homogeneous flows and fully developed turbulent channel flow indicate that the probability distribution function (pdf) of relative helicity density exhibits at most a 20 percent deviation from a flat distribution. Isotropic flows exhibit a slight helical nature but the presence of mean strain in homogeneous turbulence suppresses helical behavior. All the homogeneous turbulent flows studied show no correlation between relative helicity density and the dissipation of turbulent kinetic energy. The channel flow simulations indicate that, except for low-dissipation regions near the outer edge of the buffer layer, there is no tendency for the flow to be helical. The strong peaks in the relative helicity density pdf and the association of these peaks with regions of low dissipation found in previous simulations by Pelz et al.(1985) are not observed.

  10. Surgically assisted rapid palatal expansion with tent screws and a custom-made palatal expander: a case report.

    PubMed

    Park, Kang-Nam; Lee, Chang Youn; Park, In Young; Kim, Jwa Young; Yang, Byoungeun

    2015-12-01

    Rapid palatal expansion(RPE) with the tooth-born appliance is not sufficient to apply to the patients with periodontal problem or insufficient tooth anchorage, and it leads to tipping of the anchorage teeth and increasing teeth mobility and root resorption. To avoid these disadvantages, we present the case using palatal screws and custommade palatal expander. A 23-year-old patient underwent surgically assisted rapid maxillary expansion with the Hyrax expansion using 4 tent screws. The study models were used to measure the pre-/-post surgical width of the anterior and posterior dental arches with a digital sliding caliper. In the result, the custom-made palatal expander with 4 tent screws is suitable for delivering a force to the mid-palatal suture expansion. And it is low cost, small sized and simply applied. The results indicated that maxillary expansion with the custom-made palatal anchorage device is predictable and stable technique without significant complications in patients.

  11. [Clinical implementation of dose reconstruction and dose-guided intensity modulated radiotherapy for helical tomotherapy].

    PubMed

    Yao, Weirong; Xu, Shouping; Du Lei; Xie, Chuanbin; Ma, Lin

    2012-09-01

    To implement dose reconstruction and dose-guided intensity modulated radiotherapy for helical tomotherapy. Dose reconstruction was implemented on adaptive helical tomotherapy with the online megavoltage CT (MVCT) imaging from a patient with nasopharyngeal cancer. The differences of isodose line between actual and planned deposition were analysis in 3D distribution, on which the hot spot and cold spot were lined. The dose delivered to these areas was modulated in later fractions to keep the planned requirement. The differences between actual and planned isodose line were shown on the image visually. The modulation to the hot spot and cold spot in later fraction corrected the incorrectly delivered dose to achieve the requirement of primary plan. The dose reconstruction and dose-guided intensity modulated radiotherapy can be implemented in adaptive helical tomotherapy.

  12. Diagnosing subtle palatal anomalies: Validation of video-analysis and assessment protocol for diagnosing occult submucous cleft palate.

    PubMed

    Rourke, Ryan; Weinberg, Seth M; Marazita, Mary L; Jabbour, Noel

    2017-09-01

    Submucous cleft palate (SMCP) classically involves bifid uvula, zona pellucida, and notched hard palate. However, patients may present with more subtle anatomic abnormalities. The ability to detect these abnormalities is important for surgeons managing velopharyngeal dysfunction (VPD) or considering adenoidectomy. Validate an assessment protocol for diagnosis of occult submucous cleft palate (OSMCP) and identify physical examination features present in patients with OSMCP in the relaxed and activated palate positions. Study participants included patients referred to a pediatric VPD clinic with concern for hypernasality or SMCP. Using an appropriately encrypted iPod touch, transoral video was obtained for each patient with the palate in the relaxed and activated positions. The videos were reviewed by two otolaryngologists in normal speed and slow-motion, as needed, and a questionnaire was completed by each reviewer pertaining to the anatomy and function of the palate. 47 patients, with an average age of 4.6 years, were included in the study over a one-year period. Four videos were unusable due to incomplete view of the palate. The most common palatal abnormality noted was OSMCP, diagnosed by each reviewer in 26/43 and 30/43 patients respectively. Using the assessment protocol, agreement on palatal diagnosis was 83.7% (kappa = 0.68), indicating substantial agreement, with the most prevalent anatomic features being vaulted palate elevation (96%) and visible notching of hard palate (75%). The diagnosis of subtle palatal anomalies is difficult and can be subjective. Using the proposed video-analysis method and assessment protocol may improve reliability of diagnosis of OSMCP. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Phases in holographic helical superconductor

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Subir; Paul, Chandrima

    2017-05-01

    We study SU(2)×U(1) gauge theory with Chern-Simons term, coupled to scalar field in adjoint, in a probe approximation by ignoring back reaction on metric. Considering a simple ansatz for non-Abelian gauge field with helical structure, we find it admits s-wave and p-wave phases along with their coexistence. We study free energies for different phases along with those for p-wave phases for different values of pitch and frequency dependence of optical conductivities below critical temperature.

  14. Neutrino helicity asymmetries in leptogenesis

    SciTech Connect

    Bento, Luis; Santos, Francisco C.

    2005-05-01

    It is pointed out that the heavy singlet neutrinos characteristic of leptogenesis develop asymmetries in the abundances of the two helicity states as a result of the same mechanism that generates asymmetries in the standard lepton sector. Neutrinos and standard leptons interchange asymmetries in collisions with each other. It is shown that an appropriate quantum number, B-L{sup '}, combining baryon, lepton and neutrino asymmetries, is not violated as fast as the standard B-L. This suppresses the washout effects relevant for the derivation of the final baryon asymmetry. One presents detailed calculations for the period of neutrino thermal production in the framework of the singlet seesaw mechanism.

  15. Magnetic helicity in emerging solar active regions

    SciTech Connect

    Liu, Y.; Hoeksema, J. T.; Bobra, M.; Hayashi, K.; Sun, X.; Schuck, P. W.

    2014-04-10

    Using vector magnetic field data from the Helioseismic and Magnetic Imager instrument aboard the Solar Dynamics Observatory, we study magnetic helicity injection into the corona in emerging active regions (ARs) and examine the hemispheric helicity rule. In every region studied, photospheric shearing motion contributes most of the helicity accumulated in the corona. In a sample of 28 emerging ARs, 17 follow the hemisphere rule (61% ± 18% at a 95% confidence interval). Magnetic helicity and twist in 25 ARs (89% ± 11%) have the same sign. The maximum magnetic twist, which depends on the size of an AR, is inferred in a sample of 23 emerging ARs with a bipolar magnetic field configuration.

  16. Building blocks for subleading helicity operators

    NASA Astrophysics Data System (ADS)

    Kolodrubetz, Daniel W.; Moult, Ian; Stewart, Iain W.

    2016-05-01

    On-shell helicity methods provide powerful tools for determining scattering amplitudes, which have a one-to-one correspondence with leading power helicity operators in the Soft-Collinear Effective Theory (SCET) away from singular regions of phase space. We show that helicity based operators are also useful for enumerating power suppressed SCET operators, which encode subleading amplitude information about singular limits. In particular, we present a complete set of scalar helicity building blocks that are valid for constructing operators at any order in the SCET power expansion. We also describe an interesting angular momentum selection rule that restricts how these building blocks can be assembled.

  17. Magnetic helicity distribution in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Yang, Shangbin; Büchner, Jörg; Zhang, Hongqi

    We have developed a method to derive the relative magnetic helicity in the solar corona based on the magnetic helicity flux at the solar photosphere. We apply the method to the two newly emerging active regions (ARs) with simple and complex magnetic structures respectively. It is found that the helicity change rate in the solar corona is consistent with the helicity flux at the solar photosphere. However, the accumulated magnetic helicity in the solar corona for the simple one reverse sign as time changed. For the complex one, there is a continuous magnetic helicity accumulated just before the occurrence of solar storm, which may reflect the formation of the magnetic flux rope. It is also found that 90% of magnetic helicity is accumulated in less than 1.1 solar radius both for the two ARs After discussing the different sources of magnetic helicity, we suggested that the long term of differential rotations could play an important role to the accumulation of magnetic helicity in the solar corona and the interplanetary space, together with strong magnetic flux emergency at the solar photosphere.

  18. Higher helicity invariants and solar dynamo

    NASA Astrophysics Data System (ADS)

    Sokolov, D. D.; Illarionov, E. A.; Akhmet'ev, P. M.

    2017-01-01

    Modern models of nonlinear dynamo saturation in celestial bodies (specifically, on the Sun) are largely based on the consideration of the balance of magnetic helicity. This physical variable has also a topological meaning: it is associated with the linking coefficient of magnetic tubes. In addition to magnetic helicity, magnetohydrodynamics has a number of topological integrals of motion (the so-called higher helicity moments). We have compared these invariants with magnetic helicity properties and concluded that they can hardly serve as nonlinear constraints on dynamo action.

  19. Building blocks for subleading helicity operators

    SciTech Connect

    Kolodrubetz, Daniel W.; Moult, Ian; Stewart, Iain W.

    2016-05-24

    On-shell helicity methods provide powerful tools for determining scattering amplitudes, which have a one-to-one correspondence with leading power helicity operators in the Soft-Collinear Effective Theory (SCET) away from singular regions of phase space. We show that helicity based operators are also useful for enumerating power suppressed SCET operators, which encode subleading amplitude information about singular limits. In particular, we present a complete set of scalar helicity building blocks that are valid for constructing operators at any order in the SCET power expansion. In conclusion, we also describe an interesting angular momentum selection rule that restricts how these building blocks can be assembled.

  20. RF helicity injection and current drive

    NASA Astrophysics Data System (ADS)

    Hamamatsu, K.; Fukuyama, A.; Itoh, S.-I.; Itoh, K.; Azumi, M.

    1990-07-01

    The relation between (Range of Frequency) RF-driven current and wave helicity is analytically and numerically studied for tokamak plasma. The helicity conversion coefficient from the wave to the plasma is generally obtained and numerically examined for the waves in the range of ion cyclotron frequency. The wave propagation equation is solved as a boundary-value problem with one-dimensional inhomogeneities. It is shown that the wave helicity well satisfies the continuity equation. It was confirmed that the RF-helicity injection is not an identical phenomenon of the reduction of the one turn loop voltage due to the RF-driven current.

  1. Helical axis stellarator with noninterlocking planar coils

    DOEpatents

    Reiman, Allan; Boozer, Allen H.

    1987-01-01

    A helical axis stellarator using only noninterlocking planar, non-circular coils, generates magnetic fields having a magnetic well and large rotational transform with resultant large equilibrium beta.

  2. Effects of variation of the timing of palatal repair on nasality of speech in complete cleft lip and palate children.

    PubMed

    Nandlal, B; Tewari, A; Utreja, A K; Chari, P S; Raghunathan, N

    1999-12-01

    Nasality is related to factors like velopharyngeal closure and acoustic factors pertaining to cavities. The present investigation is a retrospective study aimed at evaluating the effects of variation in the timing of palatal repair on nasality during speech development in complete cleft lip and palate cases. It has been observed that the delay in palatal repair is associated with increase in nasality. Also, from the operated complete cleft lip and palate cases, it has been observed that the early and medium repair groups had almost similar effects on nasality of speech. (if they were operated before 36 months of age).

  3. CT enterography.

    PubMed

    Zamboni, Giulia A; Raptopoulos, Vassilios

    2010-04-01

    Conventional radiologic and endoscopic evaluations of the small bowel are often limited by the length, caliber, and motility of the small bowel loops. The development of new multidetector-row CT scanners, with faster scan times and isotropic spatial resolution, allows high-resolution multiphasic and multiplanar assessment of the bowel, bowel wall, and lumen. CT Enterography (CTE) is a variant of routine abdominal scanning, geared toward more sustained bowel filling with oral contrast material, and the use of multiplanar images, that can enhance gastrointestinal (GI) tract imaging. This article examines the techniques and clinical applications of CTE in comparison with CT enteroclysis, focusing on Crohn disease, obscure GI bleeding, GI tumors, acute abdominal pain, and bowel obstruction. Copyright 2010 Elsevier Inc. All rights reserved.

  4. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    PubMed

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans.

  5. Friction Reduction for Microhole CT Drilling

    SciTech Connect

    Ken Newman; Patrick Kelleher; Edward Smalley

    2007-03-31

    The objective of this 24 month project focused on improving microhole coiled tubing drilling bottom hole assembly (BHA) reliability and performance, while reducing the drilling cost and complexity associated with inclined/horizontal well sections. This was to be accomplished by eliminating the need for a downhole drilling tractor or other downhole coiled tubing (CT) friction mitigation techniques when drilling long (>2,000 ft.) of inclined/horizontal wellbore. The technical solution to be developed and evaluated in this project was based on vibrating the coiled tubing at surface to reduce the friction along the length of the downhole CT drillstring. The Phase 1 objective of this project centered on determining the optimum surface-applied vibration system design for downhole CT friction mitigation. Design of the system would be based on numerical modeling and laboratory testing of the CT friction mitigation achieved with various types of surface-applied vibration. A numerical model was developed to predict how far downhole the surface-applied vibration would travel. A vibration test fixture, simulating microhole CT drilling in a horizontal wellbore, was constructed and used to refine and validate the numerical model. Numerous tests, with varying surface-applied vibration parameters were evaluated in the vibration test fixture. The data indicated that as long as the axial force on the CT was less than the helical buckling load, axial vibration of the CT was effective at mitigating friction. However, surface-applied vibration only provided a small amount of friction mitigation as the helical buckling load on the CT was reached or exceeded. Since it would be impractical to assume that routine field operations be conducted at less than the helical buckling load of the CT, it was determined that this technical approach did not warrant the additional cost and maintenance issues that would be associated with the surface vibration equipment. As such, the project was

  6. Putative functions of extracellular matrix glycoproteins in secondary palate morphogenesis.

    PubMed

    d'Amaro, Rocca; Scheidegger, Rolf; Blumer, Susan; Pazera, Pawel; Katsaros, Christos; Graf, Daniel; Chiquet, Matthias

    2012-01-01

    Cleft palate is a common birth defect in humans. Elevation and fusion of paired palatal shelves are coordinated by growth and transcription factors, and mutations in these can cause malformations. Among the effector genes for growth factor signaling are extracellular matrix (ECM) glycoproteins. These provide substrates for cell adhesion (e.g., fibronectin, tenascins), but also regulate growth factor availability (e.g., fibrillins). Cleft palate in Bmp7 null mouse embryos is caused by a delay in palatal shelf elevation. In contrast, palatal shelves of Tgf-β3 knockout mice elevate normally, but a cleft develops due to their failure to fuse. However, nothing is known about a possible functional interaction between specific ECM proteins and Tgf-β/Bmp family members in palatogenesis. To start addressing this question, we studied the mRNA and protein distribution of relevant ECM components during secondary palate development, and compared it to growth factor expression in wildtypewild type and mutant mice. We found that fibrillin-2 (but not fibrillin-1) mRNA appeared in the mesenchyme of elevated palatal shelves adjacent to the midline epithelial cells, which were positive for Tgf-β3 mRNA. Moreover, midline epithelial cells started expressing fibronectin upon contact of the two palatal shelves. These findings support the hypothesis that fibrillin-2 and fibronectin are involved in regulating the activity of Tgf-β3 at the fusing midline. In addition, we observed that tenascin-W (but not tenascin-C) was misexpressed in palatal shelves of Bmp7-deficient mouse embryos. In contrast to tenascin-C, tenascin-W secretion was strongly induced by Bmp7 in embryonic cranial fibroblasts in vitro. These results are consistent with a putative function for tenascin-W as a target of Bmp7 signaling during palate elevation. Our results indicate that distinct ECM proteins are important for morphogenesis of the secondary palate, both as downstream effectors and as regulators of Tgf

  7. Spheromak Power and Helicity Balance

    SciTech Connect

    Thomassen, K.I.

    2000-05-18

    This note addresses the division of gun power and helicity between the open line volume and the closed flux surface volume in a steady state flux core spheromak. Our assumptions are that fine scale turbulence maintains each region close to a Taylor state, {mu}{sub o}J = {lambda}B. The gun region that feeds these two volumes surrounded by a flux conserver is shown topologically below. (The actual geometry is toroidal). Flux and current from the magnetized gun flow on open lines around the entire closed surface containing the spheromak. The gun current flows down the potential gradient, the potential difference between the two ends of each line being the gun voltage. Here, the gun voltage excludes the sheath drops at each end. When these volumes have different values of {lambda} (ratio of {mu}{sub o}B{sup -2}j {center_dot} B in each region) in the open line volume V{sub 1} and the closed spheromak volume V{sub 2} the efficiency of transferring the gun power to the spheromak to sustain the ohmic loss is the {lambda}-ratio of these regions, in the limit V{sub 1} << V{sub 2}. This result follows immediately from helicity balance in that limit. Here we give an accounting of all the gun power, and do not assume a small edge (open line) region.

  8. Helical coil thermal hydraulic model

    NASA Astrophysics Data System (ADS)

    Caramello, M.; Bertani, C.; De Salve, M.; Panella, B.

    2014-11-01

    A model has been developed in Matlab environment for the thermal hydraulic analysis of helical coil and shell steam generators. The model considers the internal flow inside one helix and its associated control volume of water on the external side, both characterized by their inlet thermodynamic conditions and the characteristic geometry data. The model evaluates the behaviour of the thermal-hydraulic parameters of the two fluids, such as temperature, pressure, heat transfer coefficients, flow quality, void fraction and heat flux. The evaluation of the heat transfer coefficients as well as the pressure drops has been performed by means of the most validated literature correlations. The model has been applied to one of the steam generators of the IRIS modular reactor and a comparison has been performed with the RELAP5/Mod.3.3 code applied to an inclined straight pipe that has the same length and the same elevation change between inlet and outlet of the real helix. The predictions of the developed model and RELAP5/Mod.3.3 code are in fairly good agreement before the dryout region, while the dryout front inside the helical pipes is predicted at a lower distance from inlet by the model.

  9. Timing of palate repair affecting growth in complete unilateral cleft lip and palate.

    PubMed

    Xu, Xue; Zheng, Qian; Lu, Dawei; Huang, Ning; Li, Jingtao; Li, Sheng; Wang, Yan; Shi, Bing

    2012-12-01

    To evaluate the facial morphology characteristics of patients with complete unilateral cleft lip and palate (UCCLPs) who had undergone cleft palate repair at different times. This study included 46 nonsyndromic UCCLPs and 38 age and sex matched non-cleft patients. 35 cephalometric measurements were used to evaluate the facial morphology. Student's t-test, one-way ANOVA and rank sum tests were used for comparison. Significant difference was defined at 95% level. The data showed that UCCLPs who had palatoplasty between 7 and 12 years had greater PMP-A, PMP-ANS, Ba-ANS, Ba-A, Ba-N-ANS than those operated on before 4 years of age, and UCCLPs who had palatoplasty at 4-12 years had smaller Y-axis angle than those operated on before 4 years of age. The maxillary sagittal length increased gradually as von Langenbeck repair was delayed. UCCLPs who underwent palate repair using von Langenbeck technique at 4-12 years had a more protrusive maxilla and less clockwise rotated mandible than those repaired before 4 years. UCCLPs operated using the von Langenbeck technique at 4-12 years had better head-face morphology than those operated on before 4 years. There was no difference in facial morphology among UCCLPs with palate repair at 4-12 years. Copyright © 2012 European Assocation for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  10. Unilateral cleft lip and palate: Simultaneous early repair of the nose, anterior palate and lip

    PubMed Central

    Laberge, Louise Caouette

    2007-01-01

    Unilateral cleft lip and palate is a defect involving the lip, nose and maxilla. These structures are inter-related, and simultaneous early correction of all the aspects of the defect is necessary to obtain a satisfactory result that will be maintained with growth. The surgical technique combining various procedures is presented and compared with previously published reports. PMID:19554125

  11. Weight Gain in Children with Cleft Lip and Palate without Use of Palatal Plates

    PubMed Central

    da Silva Freitas, Renato; Lopes-Grego, Andrey Bernardo; Dietrich, Helena Luiza Douat; Cerchiari, Natacha Regina de Moraes; Nakakogue, Tabatha; Tonocchi, Rita; Gabardo, Juarez; da Silva, Éder David Borges; Forte, Antonio Jorge

    2012-01-01

    Goals/Background. To evaluate children's growth in the first year of life, who have cleft palate and lip, without the use of palatal plates. Materials/Method. Chart review was conducted, retrospectively, in the Center for Integral Assistance of Cleft Lip and Palate (CAIF), in Brazil, between 2008 and 2009. Results for both genders were compared to the data published by the World Health Organization (WHO) regarding average weight gain in children during their first year of life. Results. Patients with syndromic diagnosis and with cleft classified as preforamen were excluded, resulting in a final number of 112 patients: 56 male and 56 female. Similar patterns were seen comparing the two genders. Although it was observed weight gain below the average until the 11th month in male patients and until 9 months in female patients, both genders remained at the 50th percentile (p50) and improved after the 4th month of age for boys and the 9th month of age for girls. Conclusion. Children with cleft palate weigh less than regular children during their first months of life. At the end of the first year, weight gain is similar comparing normal and affected children. However, factors that optimized weight gain included choosing the best treatment for each case, proper guidance, and multiprofessional integrated care. PMID:23304489

  12. Segregation of helicity in inertial wave packets

    NASA Astrophysics Data System (ADS)

    Ranjan, A.

    2017-03-01

    Inertial waves are known to exist in the Earth's rapidly rotating outer core and could be important for the dynamo generation. It is well known that a monochromatic inertial plane wave traveling parallel to the rotation axis (along positive z ) has negative helicity while the wave traveling antiparallel (negative z ) has positive helicity. Such a helicity segregation, north and south of the equator, is necessary for the α2-dynamo model based on inertial waves [Davidson, Geophys. J. Int. 198, 1832 (2014), 10.1093/gji/ggu220] to work. The core is likely to contain a myriad of inertial waves of different wave numbers and frequencies. In this study, we investigate whether this characteristic of helicity segregation also holds for an inertial wave packet comprising waves with the same sign of Cg ,z, the z component of group velocity. We first derive the polarization relations for inertial waves and subsequently derive the resultant helicity in wave packets forming as a result of superposition of two or more waves. We find that the helicity segregation does hold for an inertial wave packet unless the wave numbers of the constituent waves are widely separated. In the latter case, regions of opposite color helicity do appear, but the mean helicity retains the expected sign. An illustration of this observation is provided by (a) calculating the resultant helicity for a wave packet formed by superposition of four upward-propagating inertial waves with different wave vectors and (b) conducting the direct numerical simulation of a Gaussian eddy under rapid rotation. Last, the possible effects of other forces such as the viscous dissipation, the Lorentz force, buoyancy stratification, and nonlinearity on helicity are investigated and discussed. The helical structure of the wave packet is likely to remain unaffected by dissipation or the magnetic field, but can be modified by the presence of linearly stable stratification and nonlinearity.

  13. Differential microRNA expression in cultured palatal fibroblasts from infants with cleft palate and controls.

    PubMed

    Schoen, Christian; Glennon, Jeffrey C; Abghari, Shaghayegh; Bloemen, Marjon; Aschrafi, Armaz; Carels, Carine E L; Von den Hoff, Johannes W

    2017-05-09

    The role of microRNAs (miRNAs) in animal models of palatogenesis has been shown, but only limited research has been carried out in humans. To date, no miRNA expression study on tissues or cells from cleft palate patients has been published. We compared miRNA expression in palatal fibroblasts from cleft palate patients and age-matched controls. Cultured palatal fibroblasts from 10 non-syndromic cleft lip and palate patients (nsCLP; mean age: 18 ± 2 months), 5 non-syndromic cleft palate only patients (nsCPO; mean age: 17 ± 2 months), and 10 controls (mean age: 24 ± 5 months) were analysed with next-generation small RNA sequencing. All subjects are from Western European descent. Sequence reads were bioinformatically processed and the differentially expressed miRNAs were technically validated using quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Using RNA sequencing, three miRNAs (hsa-miR-93-5p, hsa-miR-18a-5p, and hsa-miR-92a-3p) were up-regulated and six (hsa-miR-29c-5p, hsa-miR-549a, hsa-miR-3182, hsa-miR-181a-5p, hsa-miR-451a, and hsa-miR-92b-5p) were down-regulated in nsCPO fibroblasts. One miRNA (hsa-miR-505-3p) was down-regulated in nsCLP fibroblasts. Of these, hsa-miR-505-3p, hsa-miR-92a, hsa-miR-181a, and hsa-miR-451a were also differentially expressed using RT-PCR with a higher fold change than in RNAseq. The small sample size may limit the value of the data. In addition, interpretation of the data is complicated by the fact that biopsy samples are taken after birth, while the origin of the cleft lies in the embryonic period. This, together with possible effects of the culture medium, implies that only cell-autonomous genetic and epigenetic differences might be detected. For the first time, we have shown that several miRNAs appear to be dysregulated in palatal fibroblasts from patients with nsCLP and nsCPO. Furthermore, large-scale genomic and expression studies are needed to validate these findings.

  14. Micro-Computed Tomography Analysis of the Root Canal Morphology of Palatal Roots of Maxillary First Molars.

    PubMed

    Marceliano-Alves, Marília; Alves, Flávio Rodrigues Ferreira; Mendes, Daniel de Melo; Provenzano, José Claudio

    2016-02-01

    A thorough knowledge of root canal anatomy is critical for successful root canal treatments. This study evaluated the internal anatomy of the palatal roots of maxillary first molars with micro-computed tomography (microCT). The palatal roots of extracted maxillary first molars (n = 169) were scanned with microCT to determine several anatomic parameters, including main canal classification, lateral canal occurrence and location, degree of curvature, main foramen position, apical constriction presence, diameters 1 and 2 mm from the apex and 1 mm from the foramen, minor dentin thickness in those regions, canal volume, surface area, and convexity. All canals were classified as Vertucci type I. The cross sections were oval in 61% of the canals. Lateral canals were found in 25% of the samples. The main foramen did not coincide with the root apex in 95% of the cases. Only 8% of the canals were classified as straight. Apical constriction was identified in 38% of the roots. The minor and major canal diameters and minor dentin thickness were decreased near the apex. The minor dentin thickness 1 mm from the foramen was 0.82 mm. The palatal canals exhibited a volume of 6.91 mm(3) and surface area of 55.31 mm(2) and were rod-shaped. The root canals of the palatal roots were classified as type I. However, some factors need to be considered during the treatment of these roots, including the frequent ocurrence of moderate/severe curvatures, oval-shaped cross-sections, and lateral canals, noncoincidence of the apical foramen with the root apex, and absence of apical constriction in most cases. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  15. A theoretically exact reconstruction algorithm for helical cone-beam differential phase-contrast computed tomography.

    PubMed

    Li, Jing; Sun, Yi; Zhu, Peiping

    2013-08-21

    Differential phase-contrast computed tomography (DPC-CT) reconstruction problems are usually solved by using parallel-, fan- or cone-beam algorithms. For rod-shaped objects, the x-ray beams cannot recover all the slices of the sample at the same time. Thus, if a rod-shaped sample is required to be reconstructed by the above algorithms, one should alternately perform translation and rotation on this sample, which leads to lower efficiency. The helical cone-beam CT may significantly improve scanning efficiency for rod-shaped objects over other algorithms. In this paper, we propose a theoretically exact filter-backprojection algorithm for helical cone-beam DPC-CT, which can be applied to reconstruct the refractive index decrement distribution of the samples directly from two-dimensional differential phase-contrast images. Numerical simulations are conducted to verify the proposed algorithm. Our work provides a potential solution for inspecting the rod-shaped samples using DPC-CT, which may be applicable with the evolution of DPC-CT equipments.

  16. Vomer flap for hard palate repair is related to favorable maxillary growth in unilateral cleft lip and palate.

    PubMed

    Liao, Yu-Fang; Lee, Ying-Hsin; Wang, Ruby; Huang, Chiung-Shing; Chen, Philip Kuo-Ting; Lo, Lun-Jou; Chen, Yu-Ray

    2014-05-01

    Vomer flap repair is assumed to improve maxillary growth because of reduced scarring in growth-sensitive areas of the palate. Our aim was to evaluate whether facial growth in patients with unilateral cleft lip and palate was significantly affected by the technique of hard palate repair (vomer flap versus two-flap). For this retrospective longitudinal study, we analyzed 334 cephalometric radiographs from 95 patients with nonsyndromic complete unilateral cleft lip and palate who underwent hard palate repair by two different techniques (vomer flap versus two-flap). Clinical notes were reviewed to record treatment histories. Cephalometry was used to determine facial morphology and growth rate. The associations among facial morphology at age 20, facial growth rate, and technique of hard palate repair were assessed using generalized estimating equation analysis. The hard palate repair technique significantly influenced protrusion of the maxilla (SNA: β = -3.5°, 95 % CI = -5.2-1.7; p = 0.001) and the anteroposterior jaw relation (ANB: β = -4.2°, 95 % CI = -6.4-1.9; p = 0.001; Wits: β = -5.7 mm, 95 % CI = -9.6-1.2; p = 0.01) at age 20, and their growth rates (SNA p = 0.001, ANB p < 0.01, and Wits p = 0.02). The results suggest that in patients with unilateral cleft lip and palate, vomer flap repair has a smaller adverse effect than two-flap on growth of the maxilla. This effect on maxillary growth is on the anteroposterior development of the alveolar maxilla and is progressive with age. We now perform hard palate closure with vomer flap followed by soft palate closure using Furlow palatoplasty. These findings may improve treatment outcome by modifying the treatment protocol for patients with unilateral cleft lip and palate.

  17. Muencke syndrome with cleft lip and palate.

    PubMed

    Anderson, Peter J; Snell, Broughton; Moore, Mark H

    2013-07-01

    Muencke syndrome results from mutations in the FGFR3 gene, and although it is well recognized that the clinical presentation is variable, the important key finding includes coronal synostosis. We present a family where a mother with proven FGFR3 Pro250Arg mutation gave birth to identical twins both of whom had craniosynostosis but had coexisting bilateral cleft lip and palate. We believe that this is the first description of clefting occurring in conjunction with Muencke syndrome and so further extends the range of phenotypic variation that can occur in this syndrome.

  18. Genetics of Cleft Palate and Velopharyngeal Insufficiency

    PubMed Central

    Sweeney, Walter M.; Lanier, Steve T.; Purnell, Chad A.; Gosain, Arun K.

    2015-01-01

    Velopharyngeal insufficiency (VPI) can occur in the setting of an unrepaired or repaired cleft lip and palate. The rate of VPI has been documented as high as 33% in some studies with higher rates of recurrences following surgery associated with genetic syndromes such as 22q11.2 deletions. The primary cause of VPI in these groups is still identified as the anatomic abnormalities of the velum. In this review, the anatomy and physiology of the velum are discussed along with genetic mutations associated with VPI. PMID:27617110

  19. A case of hard palate perforation

    PubMed Central

    Saroch, Atul; Pannu, Ashok Kumar

    2016-01-01

    Tuberculosis (TB) is a major public health problem in developing countries. Lung is most common affected organ, however extra pulmonary tuberculosis (EPTB) is also not uncommon. The clinical manifestations of EPTB may be non-specific that mimics other diseases and is usually misdiagnosed. Therefore, high clinical suspicion of EPTB infection is important, especially in endemic areas. Here, we present a case of hard palate perforation that proved to be tuberculous in origin. The diagnosis was made by histo-pathological examination and positive TB Polymerase chain reaction (PCR). PMID:28349008

  20. Surgical correction of cleft lip and palate.

    PubMed

    Jayaram, Rahul; Huppa, Christoph

    2012-01-01

    Surgical cleft repair aims to restore function of the oro-nasal sphincter and oro-nasal soft tissues and re-establish the complex relationship between perioral and perinasal muscle rings without compromising subsequent mid-facial growth and development. Here we review the surgical anatomy of this region, optimal timing for surgical repair and current thinking on the use of surgical adjuncts. In addition, an overview of current surgical techniques available for the repair of cleft lip, cleft palate and velopharyngeal insufficiency is presented. Finally, we briefly discuss nasal revision surgery and the use of osteotomy, including distraction osteogenesis in the cleft patient.

  1. Interspeaker variability in hard palate morphology and vowel production.

    PubMed

    Lammert, Adam; Proctor, Michael; Narayanan, Shrikanth

    2013-12-01

    Differences in vocal tract morphology have the potential to explain interspeaker variability in speech production. The potential acoustic impact of hard palate shape was examined in simulation, in addition to the interplay among morphology, articulation, and acoustics in real vowel production data. High-front vowel production from 5 speakers of American English was examined using midsagittal real-time magnetic resonance imaging data with synchronized audio. Relationships among hard palate morphology, tongue shaping, and formant frequencies were analyzed. Simulations were performed to determine the acoustical properties of vocal tracts whose area functions are altered according to prominent hard palate variations. Simulations revealed that altering the height and position of the palatal dome alters formant frequencies. Examinations of real speech data showed that palatal morphology is not significantly correlated with any formant frequency but is correlated with major aspects of lingual articulation. Certain differences in hard palate morphology can substantially affect vowel acoustics, but those effects are not noticeable in real speech. Speakers adapt their lingual articulation to accommodate palate shape differences with the potential to substantially affect formant frequencies, while ignoring palate shape differences with relatively little acoustic impact, lending support for acoustic goals of vowel production.

  2. Palatalization and Intrinsic Prosodic Vowel Features in Russian

    ERIC Educational Resources Information Center

    Ordin, Mikhail

    2011-01-01

    The presented study is aimed at investigating the interaction of palatalization and intrinsic prosodic features of the vowel in CVC (consonant+vowel+consonant) syllables in Russian. The universal nature of intrinsic prosodic vowel features was confirmed with the data from the Russian language. It was found that palatalization of the consonants…

  3. Palatalization and Intrinsic Prosodic Vowel Features in Russian

    ERIC Educational Resources Information Center

    Ordin, Mikhail

    2011-01-01

    The presented study is aimed at investigating the interaction of palatalization and intrinsic prosodic features of the vowel in CVC (consonant+vowel+consonant) syllables in Russian. The universal nature of intrinsic prosodic vowel features was confirmed with the data from the Russian language. It was found that palatalization of the consonants…

  4. Enhancement technology improves palatability of normal and callipyge lamb

    USDA-ARS?s Scientific Manuscript database

    This research was to determine if BPI Processing Technology improved palatability of normal (NN) and callipyge (CN) lamb meat and determine the mechanism by which palatability was improved. Ten ewe and 10 wether lambs of each phenotype were harvested and carcass traits were assessed by a trained eva...

  5. Algorithms for the treatment of cleft lip and palate.

    PubMed

    Stal, S; Klebuc, M; Taylor, T D; Spira, M; Edwards, M

    1998-10-01

    Developing standardized outcomes and algorithms of treatment is a constantly evolving task. This article examines four variables in this process: cleft type, operative technique, surgical experience, and timing. Input from international cleft lip and palate programs regarding techniques and treatment modalities provide a dynamic tool for assessment and the development of guidelines in the treatment of the cleft lip and palate patient.

  6. [Cleft palate surgery with ENT-pathology correction].

    PubMed

    Radkevich, A A; Vakhrushev, S G; Gantimurov, A A; Ivanov, V A

    2014-01-01

    The article presents the cases of cleft palate surgical treatment with simultaneous intervention in ENT organs (bypass of the tympanic cavity, segmental or total adenotomy, etc.) with the restoration of vomer anatomy and hard palate reconstruction by means of super-elastic low-profile nickel titanium implant. The article describes the advantages of the method in comparison with the conventional ones.

  7. Early Speech Production of Children with Cleft Palate.

    ERIC Educational Resources Information Center

    Estrem, Theresa; Broen, Patricia A.

    1989-01-01

    The study comparing word-initial target phonemes and phoneme production of five toddlers with cleft palate and five normal toddlers found that the cleft palate children tended to target more words with word-initial nasals, approximants, and vowels and fewer words with word-initial stops, fricatives, and affricates than normal children. (Author/DB)

  8. Single-Word Intelligibility in Speakers with Repaired Cleft Palate

    ERIC Educational Resources Information Center

    Whitehill, Tara; Chau, Cynthia

    2004-01-01

    Many speakers with repaired cleft palate have reduced intelligibility, but there are limitations with current procedures for assessing intelligibility. The aim of this study was to construct a single-word intelligibility test for speakers with cleft palate. The test used a multiple-choice identification format, and was based on phonetic contrasts…

  9. The Soft Palate Friendly Speech Bulb for Velopharyngeal Insufficiency

    PubMed Central

    Kahlon, Monaliza; Gupta, Shilpa; Dhingra, Parvinder Singh

    2016-01-01

    Velopharyngeal insufficiency is an anatomic defect of the soft palate making palatopharyngeal sphincter incomplete. It is an important concern to address in patients with bilateral cleft lip and palate. Speech aid prosthesis or speech bulbs are best choice in cases where surgically repaired soft palate is too short to contact pharyngeal walls during function but these prosthesis have been associated with inadequate marginal closure, ulcerations and patient discomfort. Here is a case report of untreated bilateral cleft lip and palate associated with palatal insufficiency treated by means of palate friendly innovative speech bulb. This modified speech bulb is a combination of hard acrylic and soft lining material. The hard self-curing acrylic resin covers only the hard palate area and a permanent soft silicone lining material covering the soft palate area. A claw-shaped wire component was extended backwards from acrylic and was embedded in soft silicone to aid in retention and approximation of two materials. The advantage of adding the soft lining material in posterior area helped in covering the adequate superior extension and margins for maximal pharyngeal activity. This also improved the hypernasality, speech, comfort and overall patient acceptance. PMID:27790589

  10. Incremental Value of Adenosine-induced Stress Myocardial Perfusion Imaging with Dual-Source CT at Cardiac CT Angiography1

    PubMed Central

    Rocha-Filho, Jose A.; Blankstein, Ron; Shturman, Leonid D.; Bezerra, Hiram G.; Okada, David R.; Rogers, Ian S.; Ghoshhajra, Brian; Hoffmann, Udo; Feuchtner, Gudrun; Mamuya, Wilfred S.; Brady, Thomas J.

    2010-01-01

    Purpose: First, to assess the feasibility of a protocol involving stress-induced perfusion evaluated at computed tomography (CT) combined with cardiac CT angiography in a single examination and second, to assess the incremental value of perfusion imaging over cardiac CT angiography in a dual-source technique for the detection of obstructive coronary artery disease (CAD) in a high-risk population. Materials and Methods: Institutional review board approval and informed patient consent were obtained before patient enrollment in the study. The study was HIPAA compliant. Thirty-five patients at high risk for CAD were prospectively enrolled for evaluation of the feasibility of CT perfusion imaging. All patients underwent retrospectively electrocardiographically gated (helical) adenosine stress CT perfusion imaging followed by prospectively electrocardiographically gated (axial) rest myocardial CT perfusion imaging. Analysis was performed in three steps: (a)Coronary arterial stenoses were scored for severity and reader confidence at cardiac CT angiography, (b)myocardial perfusion defects were identified and scored for severity and reversibility at CT perfusion imaging, and (c)coronary stenosis severity was reclassified according to perfusion findings at combined cardiac CT angiography and CT perfusion imaging. The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of cardiac CT angiography before and after CT perfusion analysis were calculated. Results: With use of a reference standard of greater than 50% stenosis at invasive angiography, all parameters of diagnostic accuracy increased after CT perfusion analysis: Sensitivity increased from 83% to 91%; specificity, from 71% to 91%; PPV, from 66% to 86%; and NPV, from 87% to 93%. The area under the receiver operating characteristic curve increased significantly, from 0.77 to 0.90 (P < .005). Conclusion: A combination protocol involving adenosine perfusion CT imaging and cardiac

  11. The AGS synchrotron with four helical magnets

    SciTech Connect

    Tsoupas N.; Huang, H.; Roser, T.; MacKay, W.W.; Trbojevic, D.

    2012-05-20

    The idea of using two partial helical magnets was applied successfully to the AGS synchrotron to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. The placement of four helical magnets in the AGS ring provides many advantages over the present setup of the AGS which uses two partial helical magnets. First, the symmetric placement of the four helical magnets allows for a better control of the AGS optics with reduced values of the beta functions especially near beam injection, second, the vertical spin direction during beam injection and extraction is closer to vertical, and third, it provides for a larger 'spin tune gap', which allows the vertical and horizontal tunes to be placed, and prevent the horizontal and vertical intrinsic spin resonances of the AGS to occur during the acceleration cycle. Although the same spin gap can be obtained with a single or two partial helices, the required high field strength of a single helix makes its use impractical, and that of the double helix rather difficult. In this paper we will provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and compare these results with the present setup of the AGS that uses two partial helical magnets.

  12. Simplified Fabrication of Helical Copper Antennas

    NASA Technical Reports Server (NTRS)

    Petro, Andrew

    2006-01-01

    A simplified technique has been devised for fabricating helical antennas for use in experiments on radio-frequency generation and acceleration of plasmas. These antennas are typically made of copper (for electrical conductivity) and must have a specific helical shape and precise diameter.

  13. Soft palate preservation after tumor resection with transoral laser microsurgery.

    PubMed

    Luna-Ortiz, Kuauhyama; Gómez-Pedraza, Antonio; Mosqueda-Taylor, Adalberto

    2013-05-01

    Management and preservation of the soft palate is dependent on clinical stage and tumor histology. However, available literature is scarce regarding the palate preservation with the use of laser CO₂. We report the results obtained after management with laser surgery and soft palate preservation in three patients with salivary gland neoplasms. Three patients with minor salivary gland tumors were treated by means of transoral laser microsurgery. All tumors were assessed using magnetic resonance imaging. All tumors were >3 cm. Soft palate function was preserved and reconstruction was performed with primary closure. Patients began oral feeding the same day and were discharged after 24 h. Transoral laser microsurgery is recommended for treatment of soft palate tumors. This treatment can be considered a better option when compared with other modalities such as radio- or chemoradiotherapy which require a longer time of treatment, are more expensive and tend to produce significant toxicity.

  14. Masticatory biomechanics and its relevance to early hominid phylogeny: an examination of palatal thickness using finite-element analysis.

    PubMed

    Strait, David S; Richmond, Brian G; Spencer, Mark A; Ross, Callum F; Dechow, Paul C; Wood, Bernard A

    2007-05-01

    It has been proposed that morphological characters functionally related to mastication may be unreliable indicators of early hominid phylogeny. One hypothesis states that masticatory characters are highly prone to homoplasy. A second hypothesis states that such characters are likely to be morphologically integrated and thus violate the assumption of character independence implicit in all phylogenetic analyses. Evaluation of these hypotheses requires that masticatory features be accurately identified, but, to date, there have been relatively few attempts to test precisely which early hominid features are functionally related to chewing. This paper uses finite-element analysis to evaluate the functional relationships of a character--palatal thickness--that is one of several Paranthropus synapomorphies putatively related to mastication. A finite-element model of 145,680 elements was created from sixty-one 2-mm-thick CT scans of a Macaca fascicularis skull. The model was assigned the elastic properties of facial bone and loaded with muscle forces corresponding to the moment of centric occlusion during mastication. The model was constrained so as to produce a reaction force (corresponding to the bite force) at M(1). With a few exceptions, the strain patterns in the finite-element model compare well with those gathered from published and unpublished bone-strain experiments. The model was then modified to have a thick palate. The model was reloaded using an identical loading regime, and the strain patterns of the original and thick-palate models were compared. Although a thickened palate acts to reduce palatal strain, strains are elevated in other facial regions. This suggests that a thick palate would not have evolved in isolation as an adaptation to withstand masticatory stress. Rather, a thick palate may have evolved in concert with a suite of other facial features that share a stress-resistance function. This appears to be consistent with hypotheses positing that at

  15. Structure and interactions of biological helices

    NASA Astrophysics Data System (ADS)

    Kornyshev, Alexei A.; Lee, Dominic J.; Leikin, Sergey; Wynveen, Aaron

    2007-07-01

    Helices are essential building blocks of living organisms, be they molecular fragments of proteins ( α -helices), macromolecules (DNA and collagen), or multimolecular assemblies (microtubules and viruses). Their interactions are involved in packing of meters of genetic material within cells and phage heads, recognition of homologous genes in recombination and DNA repair, stability of tissues, and many other processes. Helical molecules form a variety of mesophases in vivo and in vitro. Recent structural studies, direct measurements of intermolecular forces, single-molecule manipulations, and other experiments have accumulated a wealth of information and revealed many puzzling physical phenomena. It is becoming increasingly clear that in many cases the physics of biological helices cannot be described by theories that treat them as simple, unstructured polyelectrolytes. The present article focuses on the most important and interesting aspects of the physics of structured macromolecules, highlighting various manifestations of the helical motif in their structure, elasticity, interactions with counterions, aggregation, and poly- and mesomorphic transitions.

  16. Elliptical Muon Helical Cooling Channel Coils

    SciTech Connect

    Kahn, S. A.; Flanagan, G.; Lopes, M. L.; Yonehara, K.

    2013-09-01

    A helical cooling channel (HCC) consisting of a pressurized gas absorber imbedded in a magnetic channel that provides solenoid, helical dipole and helical quadrupole fields has shown considerable promise in providing six-dimensional phase space reduction for muon beams. The most effective approach to implementing the desired magnetic field is a helical solenoid (HS) channel composed of short solenoid coils arranged in a helical pattern. The HS channel along with an external solenoid allows the B$_z$ and B$_{\\phi}$ components along the reference orbit to be set to any desired values. To set dB$_{\\phi}$/dr to the desired value for optimum focusing requires an additional variable to tune. We shall show that using elliptical shaped coils in the HS channel allows the flexibility to achieve the desired dB$_{\\phi}$/dr on the reference orbit without significant change to B$_z$ and B$_{\\phi}$.

  17. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... Z CT Colonography Computed tomography (CT) colonography or virtual colonoscopy uses special x-ray equipment to examine ... and blood vessels. CT colonography, also known as virtual colonoscopy, uses low dose radiation CT scanning to ...

  18. Solubilization and fractionation of paired helical filaments.

    PubMed

    González, P J; Correas, I; Avila, J

    1992-09-01

    Paired helical filaments isolated from brains of two different patients with Alzheimer's disease were extensively treated with the ionic detergent, sodium dodecyl sulphate. Filaments were solubilized at different extents, depending on the brain examined, thus suggesting the existence of two types of paired helical filaments: sodium dodecyl sulphate-soluble and insoluble filaments. In the first case, the number of structures resembling paired helical filaments greatly decreased after the detergent treatment, as observed by electron microscopy. Simultaneously, a decrease in the amount of sedimentable protein was also observed upon centrifugation of the sodium dodecyl sulfate-treated paired helical filaments. A sodium dodecyl sulphate-soluble fraction was isolated as a supernatant after low-speed centrifugation of the sodium dodecyl sulphate-treated paired helical filaments. The addition of the non-ionic detergent Nonidet-P40 to this fraction resulted in the formation of paired helical filament-like structures. When the sodium dodecyl sulphate-soluble fraction was further fractionated by high-speed centrifugation, three subfractions were observed: a supernatant, a pellet and a thin layer between these two subfractions. No paired helical filaments were observed in any of these subfractions, even after addition of Nonidet P-40. However, when they were mixed back together, the treatment with Nonidet P-40 resulted in the visualization of paired helical filament-like structures. These results suggest that at least two different components are needed for the reconstitution of paired helical filaments as determined by electron microscopy. The method described here may allow the study of the components involved in the formation of paired helical filaments and the identification of possible factors capable of blocking this process.

  19. Contractile properties of single permeabilized muscle fibers from congenital cleft palates and normal palates of Spanish goats

    USDA-ARS?s Scientific Manuscript database

    A goat model in which cleft palate is induced by the plant alkaloid, anabasine was used to determine muscle fiber integrity of the levator veli palatine muscle. It was determined that the muscle fibers of the cleft palate-induced goats were primarily of the type 2 (fast fibers) which fatigue easil...

  20. The Effect of Cleft Palate Repair on Contractile Properties of Single Permeabilized Muscle Fibers From Congenitally Cleft Goats Palates

    USDA-ARS?s Scientific Manuscript database

    A cleft palate goat model was used to study the contractile properties of the levator veli palatini (LVP) muscle which is responsible for the movement of the soft palate. In 15-25% of patients that undergo palatoplasty, residual velopharyngeal insufficiency (VPI) remains a problem and often require...

  1. Development of the Object Permanence Concept in Cleft Lip and Palate and Noncleft Lip and Palate Infants.

    ERIC Educational Resources Information Center

    Pecyna, Paula M.; And Others

    1987-01-01

    The development of the concept of object permanence was investigated with eight infants with cleft lip/palate and four nonimpaired infants. Superior performance of the cleft lip/palate group was found, possibly due to increased environmental stimulation provided by parents. (DB)

  2. Rehabilitation of a One-day-Old Neonate with Cleft Lip and Palate using Palatal Obturator: A Case Report

    PubMed Central

    Kumar Pathak, Ashish; Bhatia, Baldev; Gupta, Sailesh; Kumar Gautam, Keshav

    2012-01-01

    ABSTRACT Feeding a neonate with a complete cleft lip and palate is difficult pursuit due to communication between oral cavity and nasal cavity. A multidisciplinary approach is required to manage the complex problems involved in case of such neonates and their families. Present case is of a 1-day-old neonate having complete bilateral cleft lip and palate for which palatal obturator was constructed. A stepwise simple, easy and uncomplicated procedure for making accurate impressions, maxillary cast and fabrication of palatal obturator in infants with cleft lip and palate has been presented. The objective to present this case report is to emphasize the fact that how these palatal obturators /plates help in feeding, speech/language development, presurgical orthopedics and prevent other associated otorhinolaryngeal problems. How to cite this article: Bansal R, Pathak AK, Bhatia B, Gupta S, Gautam KK. Rehabilitation of a One-day Old Neonate with Cleft Lip and Palate using Palatal Obturator: A Case Report. Int J Clin Pediatr Dent 2012;5(2):145-147. PMID:25206156

  3. Development of the Object Permanence Concept in Cleft Lip and Palate and Noncleft Lip and Palate Infants.

    ERIC Educational Resources Information Center

    Pecyna, Paula M.; And Others

    1987-01-01

    The development of the concept of object permanence was investigated with eight infants with cleft lip/palate and four nonimpaired infants. Superior performance of the cleft lip/palate group was found, possibly due to increased environmental stimulation provided by parents. (DB)

  4. Thermal deformation of helical gears

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Fei, Ye-tai; Liu, Shan-lin

    2010-08-01

    The analytical equation for the thermal field of a helical gear under normal working condition in a stable thermal field is established using mathematical physics, and the thermal deformation of the gear can be computed using this equation. The variations of gear geometric parameters, such as radial dimension, tooth depth, spiral angle, pressure angle, flank clearance and etc., are investigated with respect to the temperature change. According to the analytical and computational results obtained using the equation, the thermal deformation of the gear is strongly dependent on the choice of parameters, which is also confirmed using simulation software (COMSOL Multiphysic software). This is significant for the improvement of the rotation precision and working efficiency of screw gears.

  5. Cationic Nitrogen Doped Helical Nanographenes.

    PubMed

    Xu, Kun; Feng, Xinliang; Berger, Reinhard; Popov, Alexey A; Weigand, Jan J; Vincon, Ilka; Machata, Peter; Hennersdorf, Felix; Zhou, Youjia; Fu, Yubin

    2017-09-13

    Herein, we report on the synthesis of a series of novel cationic nitrogen doped nanographenes (CNDN) by rhodium catalyzed annulation reactions. This powerful method allows for the synthesis of cationic nanographenes with non-planar, axial chiral geometries. Single-crystal X-ray analysis reveals helical and cove-edged structures. Compared to their all-carbon analogues, the CNDN exhibit energetically lower lying frontier orbitals with a reduced optical energy gap and an electron accepting behavior. All derivatives show quasi reversible reductions in cyclic voltammetry. Depending on the number of nitrogen dopant, in situ spectroelectrochemistry proves the formation of neutral radicals (one nitrogen dopant) or radical cations (two nitrogen dopants) upon reduction. The developed synthetic protocol paves the way for the design and synthesis of expanded nanographenes or even graphene nanoribbons containing cationic nitrogen doping. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Best packing of identical helices

    NASA Astrophysics Data System (ADS)

    Huh, Youngsik; Hong, Kyungpyo; Kim, Hyoungjun; No, Sungjong; Oh, Seungsang

    2016-10-01

    In this paper we prove the unique existence of a ropelength-minimizing conformation of the θ-spun double helix in a mathematically rigorous way, and find the minimal ropelength {{{Rop}}}* (θ )=-\\tfrac{8π }{t} where t is the unique solution in [-θ ,0] of the equation 2-2\\cos (t+θ )={t}2. Using this result, the pitch angles of the standard, triple and quadruple helices are around 39.3771^\\circ , 42.8354^\\circ and 43.8351^\\circ , respectively, which are almost identical with the approximated pitch angles of the zero-twist structures previously known by Olsen and Bohr. We also find the ropelength of the standard N-helix.

  7. The quantum Hall effect helicity

    SciTech Connect

    Shrivastava, Keshav N.

    2015-04-16

    The quantum Hall effect in semiconductor heterostructures is explained by two signs in the angular momentum j=l±s and g=(2j+1)/(2l+1) along with the Landau factor (n+1/2). These modifications in the existing theories explain all of the fractional charges. The helicity which is the sign of the product of the linear momentum with the spin p.s plays an important role for the understanding of the data at high magnetic fields. In particular it is found that particles with positive sign in the spin move in one direction and those with negative sign move in another direction which explains the up and down stream motion of the particles.

  8. Formation of helical ion chains

    NASA Astrophysics Data System (ADS)

    Nigmatullin, R.; del Campo, A.; De Chiara, G.; Morigi, G.; Plenio, M. B.; Retzker, A.

    2016-01-01

    We study the nonequilibrium dynamics of the linear-to-zigzag structural phase transition exhibited by an ion chain confined in a trap with periodic boundary conditions. The transition is driven by reducing the transverse confinement at a finite quench rate, which can be accurately controlled. This results in the formation of zigzag domains oriented along different transverse planes. The twists between different domains can be stabilized by the topology of the trap, and under laser cooling the system has a chance to relax to a helical chain with nonzero winding number. Molecular dynamics simulations are used to obtain a large sample of possible trajectories for different quench rates. The scaling of the average winding number with different quench rates is compared to the prediction of the Kibble-Zurek theory, and a good quantitative agreement is found.

  9. Progress in the magnetic helicity studies in solar physics

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Fan; Zhang, Hong-Qi

    2005-03-01

    This paper reviews the history of magnetic helicity studies and its concepts introduced into solar physics. With the physical discussions on a new measurable quantity (relative magnetic helicity), some problems in both theory and observations are pointed out. The balance of magnetic helicity attracts much attention during recent helicity research, which is discussed in detail. Both the relationship between magnetic and current helicity, and research progress in helicity's hemispheric chirality are briefly discussed. This paper summarizes the role of helicity in some solar activities, keeping an eye on the restrictive effect of helicity in solar explosive events. Some unresolved problems and highlights are also drawn.

  10. [Use of Cone Beam Computerized Tomography (CBCT) in orthodontic diagnosis and treatment planning in the presence of a palatally-impacted canine].

    PubMed

    Waugh, Robert L

    2014-12-01

    Unerupted permanent canines can present orthodontists with special challenges. Conventional two-dimensional panoramic radiographs identify the presence or absence of unerupted canines and can only help approximate their locations, when used with various classification schemes in attempts to describe their locations and estimate treatment difficulties. This article suggests using three-dimensional cone beam CT imaging as a direct objective method of evaluation and treatment planning, thereby eliminating the need for using a subjective system of classifying palatally-impacted permanent canines.

  11. Helicity Evolution at Small x

    NASA Astrophysics Data System (ADS)

    Sievert, Michael; Kovchegov, Yuri; Pitonyak, Daniel

    2017-01-01

    We construct small- x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the g1 structure function. These evolution equations resum powers of ln2(1 / x) in the polarization-dependent evolution along with the powers of ln(1 / x) in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-Nc and large-Nc &Nf limits. After solving the large-Nc equations numerically we obtain the following small- x asymptotics for the flavor-singlet g1 structure function along with quarks hPDFs and helicity TMDs (in absence of saturation effects): g1S(x ,Q2) ΔqS(x ,Q2) g1L S(x ,kT2) (1/x) > αh (1/x) 2.31√{αsNc/2 π. We also give an estimate of how much of the proton's spin may be at small x and what impact this has on the so-called ``spin crisis.'' Work supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Award Number DE-SC0004286 (YK), the RIKEN BNL Research Center, and TMD Collaboration (DP), and DOE Contract No. DE-SC0012704 (MS).

  12. Helical tomotherapy as a means of delivering accelerated partial breast irradiation.

    PubMed

    Hui, Susanta K; Das, Rupak K; Kapatoes, Jeff; Oliviera, Gustavo; Becker, Stuart; Odau, Heath; Fenwick, John D; Patel, Rakesh; Kuske, Robert; Mehta, Minesh; Paliwal, Bhudatt; Mackie, Thomas R; Fowler, Jack F; Welsh, James S

    2004-12-01

    A novel treatment approach utilizing helical tomotherapy for partial breast irradiation for patients with early-stage breast cancer is described. This technique may serve as an alternative to high dose-rate (HDR) interstitial brachytherapy and standard linac-based approaches. Through helical tomotherapy, highly conformal irradiation of target volumes and avoidance of normal sensitive structures can be achieved. Unlike HDR brachytherapy, it is noninvasive. Unlike other linac-based techniques, it provides image-guided adaptive radiotherapy along with intensity modulation. A treatment planning CT scan was obtained as usual on a post-lumpectomy patient undergoing HDR interstitial breast brachytherapy. The patient underwent catheter placement for HDR treatment and was positioned prone on a specially designed position-supporting mattress during CT. The planning target volume (PTV) was defined as the lumpectomy bed plus a 20 mm margin. The prescription dose was 34 Gy (10 fx of 3.4 Gy) in both the CT based HDR and on the tomotherapy plan. Cumulative dose-volume histograms (DVHs) were generated and analyzed for the target, lung, heart, skin, pectoralis muscle, and chest wall for both HDR brachytherapy and helical tomotherapy. Dosimetric coverage of the target with helical tomotherapy was conformal and homogeneous. "Hot spots" (> or =150% isodose line) were present around implanted dwell positions in brachytherapy plan whereas no isodose lines higher than 109% were present in the helical tomotherapy plan. Similar dose coverage was achieved for lung, pectoralis muscle, heart, chest wall and breast skin with the two methods. We also compared our results to that obtained using conventional linac-based three dimensional (3D) conformal accelerated partial breast irradiation. Dose homogeneity is excellent with 3D conformal irradiation, and lung, heart and chest wall dose is less than for either HDR brachytherapy or helical tomotherapy but skin and pectoral muscle doses were higher

  13. The frequency split method for helical cone-beam reconstruction.

    PubMed

    Shechter, G; Köhler, Th; Altman, A; Proksa, R

    2004-08-01

    A new approximate method for the utilization of redundant data in helical cone-beam CT is presented. It is based on the observation that the original WEDGE method provides excellent image quality if only little more than 180 degrees data are used for back-projection, and that significant low-frequency artifacts appear if a larger amount of redundant data are used. This degradation is compensated by the frequency split method: The low-frequency part of the image is reconstructed using little more than 180 degrees of data, while the high frequency part is reconstructed using all data. The resulting algorithm shows no cone-beam artifacts in a simulation of a 64-row scanner. It is further shown that the frequency split method hardly degrades the signal-to-noise ratio of the reconstructed images and that it behaves robustly in the presence of motion.

  14. Neural crest-specific deletion of Ldb1 leads to cleft secondary palate with impaired palatal shelf elevation

    PubMed Central

    2014-01-01

    Background LIM domain binding protein 1 (LDB1) is a transcriptional co-factor, which interacts with multiple transcription factors and other proteins containing LIM domains. Complete inactivation of Ldb1 in mice resulted in early embryonic lethality with severe patterning defects during gastrulation. Tissue-specific deletions using a conditional knockout allele revealed additional roles of Ldb1 in the development of the central nervous system, hematopoietic system, and limbs. The goal of the current study was to determine the importance of Ldb1 function during craniofacial development in mouse embryos. Results We generated tissue-specific Ldb1 mutants using Wnt1-Cre, which causes deletion of a floxed allele in the neural crest; neural crest-derived cells contribute to most of the mesenchyme of the developing face. All examined Wnt1-Cre;Ldb1 fl/- mutants suffered from cleft secondary palate. Therefore, we performed a series of experiments to investigate how Ldb1 regulated palate development. First, we examined the expression of Ldb1 during normal development, and found that Ldb1 was expressed broadly in the palatal mesenchyme during early stages of palate development. Second, we compared the morphology of the developing palate in control and Ldb1 mutant embryos using sections. We found that the mutant palatal shelves had abnormally blunt appearance, and failed to elevate above the tongue at the posterior domain. An in vitro head culture experiment indicated that the elevation defect was not due to interference by the tongue. Finally, in the Ldb1 mutant palatal shelves, cell proliferation was abnormal in the anterior, and the expression of Wnt5a, Pax9 and Osr2, which regulate palatal shelf elevation, was also altered. Conclusions The function of Ldb1 in the neural crest-derived palatal mesenchyme is essential for normal morphogenesis of the secondary palate. PMID:24433583

  15. Optimization of helical tomotherapy treatment plans for prostate cancer

    NASA Astrophysics Data System (ADS)

    Grigorov, G.; Kron, T.; Wong, E.; Chen, J.; Sollazzo, J.; Rodrigues, G.

    2003-07-01

    Helical tomotherapy (HT) is a novel treatment approach where the ring gantry irradiation geometry of a helical CT scanner is combined with an intensity-modulated megavoltage x-ray fan beam. An inverse treatment planning system (TomoTherapy Inc., Madison) was used to optimize the treatment plans for ten randomly selected prostate patients. Five different sets of margins (2, 5, 7.5 and 10 mm uniform 3D margins and a non-uniform margin of 5 to 10 mm) were employed for the prostate (GTV2) and seminal vesicles (GTV1). The dose distribution was evaluated in targets, rectum, bladder and femoral heads. HT plans are characterized by a rapid dose fall off around the target in all directions resulting in low doses (less than 30% of the dose at ICRU reference point) to the femurs in all cases. Up to a margin of 5 mm for target structures, it was always possible to satisfy the requirements for dose delivery set by RTOG protocol P-0126. Using a 'class solution', HT plans require minimal operator interaction and result in excellent sparing of normal structures in prostate radiotherapy.

  16. Breast CT.

    PubMed

    Glick, Stephen J

    2007-01-01

    Breast cancer is a serious disease that accounts for approximately 40,000 deaths per year in the United States. Unfortunately, there is no known cause of breast cancer, and therefore the best way to prevent mortality is early detection. In the past 15 years, breast cancer mortality has been reduced significantly, which is in part due to screening with film-screen mammography. Nonetheless, conventional mammography lacks sensitivity, especially for certain subgroups of women such as those with dense breast tissue, those under 50 years old, and pre- or perimenopausal women. In addition, mammography has a very poor positive predictive value for biopsy, with 70%-90% of biopsies performed turning out negative. By improving visualization of breast tissue, X-ray computerized tomography (CT) of the breast can potentially provide improvements in diagnostic accuracy over conventional mammography. Owing to recent technological developments in digital detector technology, flat-panel CT imagers dedicated to imaging of the breast are now feasible. A number of academic groups are currently researching dedicated breast CT and prototype systems are currently being evaluated in the clinical setting.

  17. Acoustic and Perceptual Analysis of Speech Adaptation to an Artificial Palate

    ERIC Educational Resources Information Center

    McAuliffe, Megan J.; Robb, Michael P.; Murdoch, Bruce E.

    2007-01-01

    The study investigated adaptation to a standard electropalatographic (EPG) practise palate in a group of eight adults (mean age = 24 years). The participants read the phrase "a CVC" over four sampling conditions: prior to inserting the palate, immediately following insertion of the palate, 45 minutes after palate insertion, and 3 hours after…

  18. Helicity within the vortex filament model.

    PubMed

    Hänninen, R; Hietala, N; Salman, H

    2016-11-24

    Kinetic helicity is one of the invariants of the Euler equations that is associated with the topology of vortex lines within the fluid. In superfluids, the vorticity is concentrated along vortex filaments. In this setting, helicity would be expected to acquire its simplest form. However, the lack of a core structure for vortex filaments appears to result in a helicity that does not retain its key attribute as a quadratic invariant. By defining a spanwise vector to the vortex through the use of a Seifert framing, we are able to introduce twist and henceforth recover the key properties of helicity. We present several examples for calculating internal twist to illustrate why the centreline helicity alone will lead to ambiguous results if a twist contribution is not introduced. Our choice of the spanwise vector can be expressed in terms of the tangential component of velocity along the filament. Since the tangential velocity does not alter the configuration of the vortex at later times, we are able to recover a similar equation for the internal twist angle to that of classical vortex tubes. Our results allow us to explain how a quasi-classical limit of helicity emerges from helicity considerations for individual superfluid vortex filaments.

  19. Magnetic Helicity in a Cyclic Convective Dynamo

    NASA Astrophysics Data System (ADS)

    Miesch, Mark S.; Zhang, Mei; Augustson, Kyle C.

    2016-05-01

    Magnetic helicity is a fundamental agent for magnetic self-organization in magnetohydrodynamic (MHD) dynamos. As a conserved quantity in ideal MHD, it establishes a strict topological coupling between large and small-scale magnetic fields. The generation of magnetic fields on scales larger than the velocity field is linked to an upscale transfer of magnetic helicity, either locally in spectral space as in the inverse cascade of magnetic helicity in MHD turbulence or non-locally, as in the turbulent alpha-effect of mean-field dynamo theory. Thus, understanding the generation, transport, and dissipation of magnetic helicity is an essential prerequisite to understanding manifestations of magnetic self-organization in the solar dynamo, including sunspots, the prominent dipole and quadrupole moments, and the 22-year magnetic activity cycle. We investigate the role of magnetic helicity in a convective dynamo model that exhibits regular magnetic cycles. The cycle is marked by coherent bands of toroidal field that persist within the convection zone and that are antisymmetric about the equator. When these toriodal bands interact across the equator, it initiates a global restructuring of the magnetic topology that contributes to the reversal of the dipole moment. Thus, the polar field reversals are preceeded by a brief reversal of the subsurface magnetic helicity. There is some evidence that the Sun may exhibit a similar magnetic helicity reversal prior to its polar field reversals.

  20. Helicity within the vortex filament model

    NASA Astrophysics Data System (ADS)

    Hänninen, R.; Hietala, N.; Salman, H.

    2016-11-01

    Kinetic helicity is one of the invariants of the Euler equations that is associated with the topology of vortex lines within the fluid. In superfluids, the vorticity is concentrated along vortex filaments. In this setting, helicity would be expected to acquire its simplest form. However, the lack of a core structure for vortex filaments appears to result in a helicity that does not retain its key attribute as a quadratic invariant. By defining a spanwise vector to the vortex through the use of a Seifert framing, we are able to introduce twist and henceforth recover the key properties of helicity. We present several examples for calculating internal twist to illustrate why the centreline helicity alone will lead to ambiguous results if a twist contribution is not introduced. Our choice of the spanwise vector can be expressed in terms of the tangential component of velocity along the filament. Since the tangential velocity does not alter the configuration of the vortex at later times, we are able to recover a similar equation for the internal twist angle to that of classical vortex tubes. Our results allow us to explain how a quasi-classical limit of helicity emerges from helicity considerations for individual superfluid vortex filaments.

  1. Helicity within the vortex filament model

    PubMed Central

    Hänninen, R.; Hietala, N.; Salman, H.

    2016-01-01

    Kinetic helicity is one of the invariants of the Euler equations that is associated with the topology of vortex lines within the fluid. In superfluids, the vorticity is concentrated along vortex filaments. In this setting, helicity would be expected to acquire its simplest form. However, the lack of a core structure for vortex filaments appears to result in a helicity that does not retain its key attribute as a quadratic invariant. By defining a spanwise vector to the vortex through the use of a Seifert framing, we are able to introduce twist and henceforth recover the key properties of helicity. We present several examples for calculating internal twist to illustrate why the centreline helicity alone will lead to ambiguous results if a twist contribution is not introduced. Our choice of the spanwise vector can be expressed in terms of the tangential component of velocity along the filament. Since the tangential velocity does not alter the configuration of the vortex at later times, we are able to recover a similar equation for the internal twist angle to that of classical vortex tubes. Our results allow us to explain how a quasi-classical limit of helicity emerges from helicity considerations for individual superfluid vortex filaments. PMID:27883029

  2. Three-dimensional palatal development between 3 and 6 years.

    PubMed

    Ciusa, Veronica; Dimaggio, Francesca Romana; Sforza, Chiarella; Ferrario, Virgilio Ferruccio

    2007-07-01

    To measure palatal landmarks of healthy nonpatient children aged 3 to 6 years with a normal deciduous dentition and to evaluate palatal shape independent of size. Fifty-eight dental casts of children with a normal and complete deciduous dentition were obtained and digitized with a computerized 3D instrument. At all ages, male and female data did not differ (Student's t-test), so the pooled values were considered. Dimensions were compared between ages by analyses of variance. Palatal slope and height increased significantly as a function of age (P < .001). Palatal length did not change with age (average: 23.1 mm). In the frontal plane, the intermolar width increased slightly with age by about 1.8 mm at the second molars, 1.1 mm at the first molars, and 0.9 mm at the canines. Palatal height in the frontal plane did not change in the posterior part of the palate, but decreased anteriorly. The intercanine distance increased by 0.9 mm with age. However, this change did not reach statistical significance. Between 3 and 6 years of age, palatal shape changed and became proportionally higher in both the frontal and sagittal planes.

  3. Morphology and function of the palatal dentition in Choristodera.

    PubMed

    Matsumoto, Ryoko; Evans, Susan E

    2016-03-01

    Choristoderes are a group of extinct freshwater reptiles that were distributed throughout Laurasia from the Middle Jurassic to the Miocene. They are inferred to have had a lifestyle similar to that of extant gavialid crocodiles, but they differed from crocodiles in retaining an extensive palatal dentition. All choristoderes had teeth on the vomers, palatines and pterygoids, and teeth are rarely present on the parasphenoid. Palatal teeth are conical, as in the marginal dentition, and form longitudinal and transverse rows. Detailed examination of different genera shows that the orientation of the palatal tooth crowns changes with their position on the palate, supporting the view that they are involved in intra-oral food transportation, presumably in combination with a fleshy tongue. Moreover, observed variation in palatal tooth shape and the width of palatal tooth batteries may provide additional clues about diet. The European Simoedosaurus lemoinei has sharper palatal teeth than its North American counterpart, S. dakotensis, suggesting a preference for softer prey - a conclusion consistent with the more gracile teeth and narrower snout.

  4. A modified feeding plate for a newborn with cleft palate.

    PubMed

    Erkan, Mustafa; Karaçay, Seniz; Atay, Arzu; Günay, Yumuşhan

    2013-01-01

    Objectives : Cleft palate is a common congenital maxillofacial defect. We wish to present the fabrication of a modified feeding plate that will adapt to the changing palatal and velopharyngeal morphology during function. Case Report : A neonate with unilateral cleft lip and palate was referred to our clinic for the fabrication of a feeding plate. Intraoral examination revealed a cleft involving the uvula and the soft palate, with an alveolar defect on the left side. An impression was taken and a dental cast was obtained. A 1-mm Bioplast clear soft plate was pressed on the model. After trimming the edges of the plate, several retentive holes were made for its attachment to the hard plate. With the Bioplast soft plate replaced on the cast, plaster was used to cover parts of the soft plate that were not to come in contact with the hard plate. Biocryl resin was put on the retentive holes and 2-mm Biocryl C Rosa-transparent plate was pressed. The edges of the plate were cut, trimmed, and polished. Conclusion : This modified feeding plate effectively obstructed the soft palate defect. The adaptation of the flexible bulb of the appliance with the soft palate was excellent. Evaluation with nasoendoscopy revealed the synchronized movement of the bulb of the appliance with the soft palate during swallowing. Soft extension of the feeding plate eliminated the risk of irritation, and the baby accepted the appliance easily.

  5. Anterior pillarplasty: a modification in cleft palate repair.

    PubMed

    Çelebiler, Özhan; Ersoy, Burak; Numanoğlu, Ayhan

    2011-07-01

    After the primary repair of cleft palate, surgeons are frequently confronted with a short soft palate and a wide velopharyngeal space, both of which are known to diminish the quality of speech. We introduce a new modification of the primary repair of cleft palate that lengthens the soft palate and helps to reduce the volume of the velopharyngeal space. Ten patients younger than 12 months with nonsyndromic cleft palate were operated on with this technique. The incision at the cleft margin extended behind the uvula as a modification to the classic design of mucoperiosteal flaps. The sagittally divided mucosal layers of each anterior tonsillar pillar are sutured at the midline 1 cm posterior to the new uvula. The rate of postoperative fistula formation and other complications were evaluated postoperatively. One patient had a uvular and partly pillar detachment at the postoperative period. All other clefts healed without complication. The primary repair of the cleft palate with the anterior pillarplasty technique is a safe and easy-to-perform procedure. This modification can effectively reduce the transverse diameter of the velopharyngeal space and increase the anteroposterior length of the palate.

  6. Presurgical orthopedic premaxillary alignment in cleft lip and palate reconstruction.

    PubMed

    Papay, F A; Morales, L; Motoki, D S; Yamashiro, D K

    1994-11-01

    Premaxillary malposition is a difficult problem in cleft lip and palate repair. Orthopedic palatal devices are excellent in positioning the premaxilla, though they are somewhat cumbersome and require complex techniques in adjusting precisely the position of the premaxilla prior to repair. A new technique has been developed for premaxillary repositioning in conjunction with palatal shelf expansion and obturation. The procedure implements microplate fixation anterior to the premaxillary segment and linked to a palatal splint by adjustable elastics. The microplate is inserted through a nasal floor incision and secured by a tight submucosal tunnel through minimal dissection between the prolabium and premaxilla. The last hole of each microplate protrudes through the mucosa and is attached to a pin-retained palatal splint by an elastic chain. Differential tension is applied to the chains to allow gradual repositioning of the protruding maxilla while the splint expands and maintains positioning of the lateral palatal segments. These elastic retractors can be adjusted by staff in the outpatient office. During the past 2 years, this technique has been used successfully in 21 consecutive patients with unilateral or bilateral cleft lip and palate. Its technical ease and design allows simple adjustments to control premaxillary positioning and growth before definitive surgical closure.

  7. Hydrodynamic interaction between two helical swimmers

    NASA Astrophysics Data System (ADS)

    Ruiz Esparza, Alejandro; Godinez, Francisco; Lauga, Eric; Zenit, Roberto

    2016-11-01

    Many motile bacteria, such as E. coli, possess several helical flagellar filaments that bundle together to form a coherent helical element for propulsion. In order to understand the process of bundling, we study the interaction between two identical helical magnetic swimmers that self propel in a highly viscous Newtonian fluid due to the rotation of an external magnetic field. Our experiments reveal that hydrodynamic interactions lead to nontrivial collective and relative effects, both in translation and rotation. We will present our experimental results and discuss the physical mechanisms responsible for our observations.

  8. Helical, dissipative, magnetohydrodynamic states with flow

    NASA Technical Reports Server (NTRS)

    Montgomery, David; Phillips, Lee; Theobald, Michael L.

    1989-01-01

    It is shown that for an axially periodic column of magnetofluid driven by an applied axial electric field, the total rate of energy dissipation (Ohmic plus viscous) can be lowered by permitting a helical component with vortical flow in the solution. The principle of minimum energy-dissipation rate suggests that this partially helical state will be preferred to the axisymmetric one that exists for the same parameters. The result is consistent with the repeated appearance of such partially-helical states in several fully three-dimensional numerical computations and is not inconsistent with the data from some confinement experiments.

  9. Polymorphic transformation of helical flagella of bacteria

    NASA Astrophysics Data System (ADS)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  10. Helicity oscillations of Dirac and Majorana neutrinos

    NASA Astrophysics Data System (ADS)

    Dobrynina, Alexandra; Kartavtsev, Alexander; Raffelt, Georg

    2016-06-01

    The helicity of a Dirac neutrino with mass m evolves under the influence of a B field because it has a magnetic dipole moment proportional to m . Moreover, it was recently shown that a polarized or anisotropic medium engenders the same effect for both Dirac and Majorana neutrinos. Because a B field polarizes a background medium, it instigates helicity oscillations even for Majorana neutrinos unless the medium is symmetric between matter and antimatter. Motivated by these observations, we review the impact of a B field and of an anisotropic or polarized medium on helicity oscillations for Dirac and Majorana neutrinos from the common perspective of in-medium dispersion.

  11. Does Hooke's law work in helical nanosprings?

    PubMed

    Ben, Sudong; Zhao, Junhua; Rabczuk, Timon

    2015-08-28

    Hooke's law is a principle of physics that states that the force needed to extend a spring by some distance is proportional to that distance. The law is always valid for an initial portion of the elastic range for nearly all helical macrosprings. Here we report the sharp nonlinear force-displacement relation of tightly wound helical carbon nanotubes at even small displacement via a molecular mechanics model. We demonstrate that the van der Waals (vdW) interaction between the intertube walls dominates the nonlinear relation based on our analytical expressions. This study provides physical insights into the origin of huge nonlinearity of the helical nanosprings.

  12. Thermally activated helicity reversals of skyrmions

    NASA Astrophysics Data System (ADS)

    Yu, X. Z.; Shibata, K.; Koshibae, W.; Tokunaga, Y.; Kaneko, Y.; Nagai, T.; Kimoto, K.; Taguchi, Y.; Nagaosa, N.; Tokura, Y.

    2016-04-01

    Magnetic bubbles with winding number S =1 are topologically equivalent to skyrmions. Here we report the discovery of helicity (in-plane magnetization-swirling direction) reversal of skyrmions, while keeping their hexagonal lattice form, at above room temperature in a thin hexaferrite magnet. We have observed that the frequency of helicity reversals dramatically increases with temperature in a thermally activated manner, revealing that the generation energy of a kink-soliton pair for switching helicity on a skyrmion rapidly decreases towards the magnetic transition temperature.

  13. Receptor-dependent mechanisms of glucocorticoid and dioxin-induced cleft palate.

    PubMed Central

    Pratt, R M

    1985-01-01

    Glucocorticoids (triamcinolone) and dioxins (TCDD) are highly specific teratogens in the mouse, in that cleft palate is the major malformation observed. Glucocorticoids and TCDD both readily cross the yolk sac and placenta and appear in the developing secondary palate. Structure-activity relationships for glucocorticoid- and TCDD-induced cleft palate suggest a receptor involvement. Receptors for glucocorticoids and TCDD are present in the palate and their levels in various mouse strains are highly correlated with their sensitivity to cleft palate induction. Receptors for glucocorticoids appear to be more prevalent in the palatal mesenchymal cells whereas those for TCDD are probably located in the palatal epithelial cells. Glucocorticoids exert their teratogenic effect on the palate by inhibiting the growth of the palatal mesenchymal cells whereas TCDD alters the terminal cell differentiation of the medial palatal epithelial cells. PMID:2998748

  14. Receptor-dependent mechanisms of glucocorticoid and dioxin-induced cleft palate

    SciTech Connect

    Pratt, R.M.

    1985-09-01

    Glucocorticoids (triamcinolone) and dioxins (TCDD) are highly specific teratogens in the mouse, in that cleft palate is the major malformation observed. Glucocorticoids and TCDD both readily cross the yolk sac and placenta and appear in the developing secondary palate. Structure-activity relationships for glucocorticoid- and TCDD-induced cleft palate suggest a receptor involvement. Receptors for glucocorticoids and TCDD are present in the palate and their levels in various mouse strains are highly correlated with their sensitivity to cleft palate induction. Receptors for glucocorticoids appear to be more prevalent in the palatal mesenchymal cells whereas those for TCDD are probably located in the palatal epithelial cells. Glucocorticoids exert their teratogenic effect on the palate by inhibiting the growth of the palatal mesenchymal cells whereas TCDD alters the terminal cell differentiation of the media palatal epithelial cells. 71 references.

  15. Prenatal diagnosis of Kniest dysplasia with three-dimensional helical computed tomography.

    PubMed

    Wada, Ryu; Sawai, Hideaki; Nishimura, Gen; Isono, Kazutomo; Minagawa, Kyoko; Takenobu, Takashi; Harada, Kayoko; Tanaka, Hiroyuki; Ishikura, Reiichi; Komori, Shinji

    2011-09-01

    Fetal three-dimensional helical computed tomography (3D-CT) has attracted attention in the diagnosis of fetal skeletal dysplasias because of limited diagnostic capabilities of standard ultrasonography to delineate the skeleton. Here we report the first instance of diagnosing Kniest dysplasia with 3D-CT. Fetal 3D-CT was performed for a fetus at 28 weeks' gestation after ultrasonography at 24 weeks had shown moderate shortening of the limbs, mild narrow thorax, and polyhydramnios. The imaging parameters were set so as to reduce estimated fetal irradiation dose to 12.39 mGy of the CT dose index volume and 442 of the dose length product. Fetal 3D-CT revealed dumbbell-shaped femora and platyspondyly with coronal cleft of the lumbar vertebral body. This warranted a diagnosis of Kniest dysplasia and corresponded well with postnatal radiographic findings. In retrospect, however, spinal deformation was somewhat underestimated due to image smoothing associated with image processing in 3D-CT. Genetic testing for COL2A1 confirmed Kniest dysplasia; i.e., a de novo mutation of A-C transversion at the splice acceptor site of the 3' end of intron 16. The combined use of 3D-CT with ultrasonography is a power tool for the prenatal diagnosis of congenital skeletal dysplasias.

  16. Use of buccal myomucosal flap for palatal lengthening in cleft palate patient: Experience of 20 cases

    PubMed Central

    Varghese, Don; Datta, Shubharanjan; Varghese, Annie

    2015-01-01

    Background: The purpose of this review was to assess the effectiveness of the buccal myomucosal flap in secondary repairs of cleft palate in 20 patients. Patients and Methods: Totally, 20 patients, who underwent secondary palatoplasty between 5 years and 8 years in which a buccal myomucosal flap was used, were reviewed retrospectively. All patients had undergone at least one previous attempted repair at other institutions. Indications for the secondary repair included velopharyngeal incompetence and/or oronasal fistula. Patients were evaluated preoperatively for oronasal fistula status, velopharyngeal competence, nasal resonance, speech quality, and nasal escape. Results: The buccal myomucosal flap was used in all 20 patients, and there was marked increase in the quality of speech as well as nasal regurgitation decreased. In patients with levator dysfunction due to poor primary surgery and glottal speech the results were inconclusive Conclusion: Palate re-repair combined with a buccal myomucosal flap, occasionally in conjunction with other techniques, is an effective method for correcting failed cleft palate repairs. Minimum donor site morbidity and complication makes the buccal flap a useful armamentarium of a cleft surgeon. PMID:25821372

  17. Helical and rod-shaped bacteria swim in helical trajectories with little additional propulsion from helical shape

    PubMed Central

    Constantino, Maira A.; Jabbarzadeh, Mehdi; Fu, Henry C.; Bansil, Rama

    2016-01-01

    It has frequently been hypothesized that the helical body shapes of flagellated bacteria may yield some advantage in swimming ability. In particular, the helical-shaped pathogen Helicobacter pylori is often claimed to swim like a corkscrew through its harsh gastric habitat, but there has been no direct confirmation or quantification of such claims. Using fast time-resolution and high-magnification two-dimensional (2D) phase-contrast microscopy to simultaneously image and track individual bacteria in bacterial broth as well as mucin solutions, we show that both helical and rod-shaped H. pylori rotated as they swam, producing a helical trajectory. Cell shape analysis enabled us to determine shape as well as the rotational and translational speed for both forward and reverse motions, thereby inferring flagellar kinematics. Using the method of regularized Stokeslets, we directly compare observed speeds and trajectories to numerical calculations for both helical and rod-shaped bacteria in mucin and broth to validate the numerical model. Although experimental observations are limited to select cases, the model allows quantification of the effects of body helicity, length, and diameter. We find that due to relatively slow body rotation rates, the helical shape makes at most a 15% contribution to propulsive thrust. The effect of body shape on swimming speeds is instead dominated by variations in translational drag required to move the cell body. Because helical cells are one of the strongest candidates for propulsion arising from the cell body, our results imply that quite generally, swimming speeds of flagellated bacteria can only be increased a little by body propulsion. PMID:28138539

  18. Helical and rod-shaped bacteria swim in helical trajectories with little additional propulsion from helical shape.

    PubMed

    Constantino, Maira A; Jabbarzadeh, Mehdi; Fu, Henry C; Bansil, Rama

    2016-11-01

    It has frequently been hypothesized that the helical body shapes of flagellated bacteria may yield some advantage in swimming ability. In particular, the helical-shaped pathogen Helicobacter pylori is often claimed to swim like a corkscrew through its harsh gastric habitat, but there has been no direct confirmation or quantification of such claims. Using fast time-resolution and high-magnification two-dimensional (2D) phase-contrast microscopy to simultaneously image and track individual bacteria in bacterial broth as well as mucin solutions, we show that both helical and rod-shaped H. pylori rotated as they swam, producing a helical trajectory. Cell shape analysis enabled us to determine shape as well as the rotational and translational speed for both forward and reverse motions, thereby inferring flagellar kinematics. Using the method of regularized Stokeslets, we directly compare observed speeds and trajectories to numerical calculations for both helical and rod-shaped bacteria in mucin and broth to validate the numerical model. Although experimental observations are limited to select cases, the model allows quantification of the effects of body helicity, length, and diameter. We find that due to relatively slow body rotation rates, the helical shape makes at most a 15% contribution to propulsive thrust. The effect of body shape on swimming speeds is instead dominated by variations in translational drag required to move the cell body. Because helical cells are one of the strongest candidates for propulsion arising from the cell body, our results imply that quite generally, swimming speeds of flagellated bacteria can only be increased a little by body propulsion.

  19. Otologic Concerns for Cleft Lip and Palate Patient.

    PubMed

    Berryhill, Wayne

    2016-05-01

    Understanding eustachian tube physiology and anticipating probable eustachian tube dysfunction is an important component of cleft palate management. This article provides a brief summary of the otologic physiology and issues that may be of concern to cleft palate management. It is of critical importance not only to provide primary closure of the cleft palate, but also to recognize that along with speech, hearing has a critical component to the educational and social success of all individuals. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Speech evaluation and treatment for patients with cleft palate.

    PubMed

    Kuehn, David P; Henne, Lisa J

    2003-02-01

    This compendium has been written in conjunction with a cleft lip and palate surgical mission that took place in Villahermosa, Mexico, February 4-9, 2001. Fifty children, 10 per day, received lip or palate surgery. This report, available in both English and Spanish, is intended as a practical and concise guide to basic aspects of evaluation and treatment of speech disorders associated with cleft palate. More detailed and comprehensive sources dealing with this topic are available and have been reviewed by D. P. Kuehn and K. T. Moller (2000).

  1. Simplified feeding appliance for an infant with cleft palate.

    PubMed

    Masih, Shaila; Chacko, Reena Annie; Thomas, Abi M; Singh, Namita; Thomas, Rodny; Abraham, Deena

    2014-01-01

    A child born with cleft palate may experience difficulties while feeding. Early surgical treatment may need to be postponed until certain age and weight gain of the infant. The case presented here is of a 1-month-old neonate born with cleft palate, assisted with a new feeding appliance made with ethylene vinyl acetate using pressure molding technique to aid in proper feeding. The patient's weight and health significantly improved after the insertion of obturator. The advantages of this material included being lightweight, moldability, good palatal fit and decreased soft tissue injury.

  2. Dynamic helical computed tomography of the pituitary gland in healthy dogs.

    PubMed

    Van der Vlugt-Meijer, Roselinda H; Meij, Björn P; Voorhout, George

    2007-01-01

    Dynamic helical computed tomography (CT) of the pituitary gland can be used to image the three-dimensional shape and dimensions of abnormalities within the pituitary gland. The aim of this study was to develop a protocol for dynamic helical CT of the pituitary gland in healthy dogs as a future reference study for patients with pituitary disease. Dynamic helical series of nine scans of the pituitary gland during and following contrast medium injection were performed in six healthy dogs using the following protocols: a series with 1 mm collimation and a table feed per X-ray tube rotation of 2 mm (pitch of 2) in six dogs, a series with 2 mm collimation and pitch of 2 in three dogs, and a series with 1 mm collimation and pitch of 1 in three other dogs. Multiplanar reconstructions of the images were made using a reconstruction index of 0.5. Images of all series were assessed visually for enhancement of the arteries, the neurohypophysis, and the adenohypophysis. The enhancement pattern of the neurohypophysis was distinguished adequately from that of the adenohypophysis in five dogs that were scanned with 1 mm collimation and pitch of 2, but the difference was less discernable when the other protocols were used. The carotid artery, its trifurcation, and the arterial cerebral circle were best visualized in dorsal reconstructions. Dynamic helical CT of the pituitary gland in healthy dogs can be performed with 1 mm collimation and pitch of 2, and a scan length that includes the entire pituitary region. Using this protocol, with the specific scanner used, the neurohypophysis, the adenohypophysis, and the surrounding vascular structures are adequately visualized.

  3. The anatomy of the dog soft palate. III. Histological evaluation of the caudal soft palate in brachycephalic neonates.

    PubMed

    Pichetto, Michela; Arrighi, Silvana; Gobbetti, Matteo; Romussi, Stefano

    2015-03-01

    A thickened and abnormally long soft palate is mostly involved in the pathogenesis of both nasopharyngeal and oropharyngeal narrowing, affecting the respiratory activity in virtually all of the brachycephalic dogs suffering from Brachycephalic Airway Obstructive Syndrome (BAOS). The morphology of the soft palate in adult mesaticephalic and brachycephalic dogs has been previously described. In this article specimens from brachycephalic dog neonates (N=10) dead from one to 3 hr after birth of unrelated conditions were collected and histologically evaluated at three transverse levels to describe the microscopic aspect of the caudal part of the soft palate. The soft palate of neonate brachycephalic dogs was histologically characterized by a musculo-connective axis containing salivary glands and coated by a mucosal layer on both the nasopharyngeal and the oral side. Quali-quantitative features, such as thickened superficial epithelium, broad oedema of the lamina propria, mucous gland hyperplasia and diverse muscular modifications described in adult brachycephalic dogs, were not observed in the soft palate of brachycephalic neonate dogs. The lack of tissue lesions in the soft palate of newborn brachycephalic dogs further supports the hypothesis that inspiratory depression during the inspiratory phase causes chronic vibration and microtrauma, which lead to soft palate alterations in adult brachycephalic dogs starting from the earliest grade of the respiratory syndrome. Overall, this study provides baseline information for the comprehension of the pathogenesis of BAOS. © 2014 Wiley Periodicals, Inc.

  4. Obturator prostheses following palatal resection: clinical cases.

    PubMed

    Tirelli, G; Rizzo, R; Biasotto, M; Di Lenarda, R; Argenti, B; Gatto, A; Bullo, F

    2010-02-01

    Malignant tumours of the upper gum and hard palate account for 1-5% of malignant neoplasms of the oral cavity; two thirds of the lesions which involve these areas are squamous cell carcinomas. Most of these carcinomas are diagnosed late, when they invade the underlying bone. The procedures of choice for removal are: alveolectomy, palatectomy, maxillectomy, which may be total or partial. Surgical reconstruction of the defect may be carried out using a wide range of microvascularized flaps: osteomuscolocutaneous of the internal iliac crest, an osteocutaneous flap of the fibula or scapula, fascia, or osteocutaneous radial flap, or a pedicled flap of temporal muscle. These flaps are supported by single or multiple obturator prostheses. Rehabilitation via palatal obturators is preferred in patients with a poor prognosis or in weak condition. Rehabilitation aims to: restore the separation between the oral and nasal cavities, enable the patient to swallow, maintain or provide mastication, sufficient occlusion and mandibular support, support the soft facial tissues, re-establish speech and restore an aesthetically pleasing smile. Hence, it is crucial to work in close cooperation with the staff who makes the prosthesis and who evaluates the case when the surgery is planned and obtains the necessary gnatological, anatomical and functional information. Thereafter, during the surgical stage, for the immediate obturators, or in the successive days, for the temporary obturators, work is devoted to making the prostheses. In this regard, the Odonto-prostheses Service of the Stomatological Clinic does not follow a rigid protocol but materials and techniques are selected on a personal basis, according to the features of each individual clinical case. Mobile rehabilitative systems are the systems of choice, both of which related to the traditional concepts of retention and stability and systems of self-stabilizing prostheses according to J. Dichamp, albeit modified in materials

  5. Obturator prostheses following palatal resection: clinical cases

    PubMed Central

    Tirelli, G; Rizzo, R; Biasotto, M; Di Lenarda, R; Argenti, B; Gatto, A; Bullo, F

    2010-01-01

    Summary Malignant tumours of the upper gum and hard palate account for 1-5% of malignant neoplasms of the oral cavity; two thirds of the lesions which involve these areas are squamous cell carcinomas. Most of these carcinomas are diagnosed late, when they invade the underlying bone. The procedures of choice for removal are: alveolectomy, palatectomy, maxillectomy, which may be total or partial. Surgical reconstruction of the defect may be carried out using a wide range of microvascularized flaps: osteomuscolocutaneous of the internal iliac crest, an osteocutaneous flap of the fibula or scapula, fascia, or osteocutaneous radial flap, or a pedicled flap of temporal muscle. These flaps are supported by single or multiple obturator prostheses. Rehabilitation via palatal obturators is preferred in patients with a poor prognosis or in weak condition. Rehabilitation aims to: restore the separation between the oral and nasal cavities, enable the patient to swallow, maintain or provide mastication, sufficient occlusion and mandibular support, support the soft facial tissues, re-establish speech and restore an aesthetically pleasing smile. Hence, it is crucial to work in close cooperation with the staff who makes the prosthesis and who evaluates the case when the surgery is planned and obtains the necessary gnatological, anatomical and functional information. Thereafter, during the surgical stage, for the immediate obturators, or in the successive days, for the temporary obturators, work is devoted to making the prostheses. In this regard, the Odonto-prostheses Service of the Stomatological Clinic does not follow a rigid protocol but materials and techniques are selected on a personal basis, according to the features of each individual clinical case. Mobile rehabilitative systems are the systems of choice, both of which related to the traditional concepts of retention and stability and systems of self-stabilizing prostheses according to J. Dichamp, albeit modified in

  6. Early hard palate closure using a vomer flap in unilateral cleft lip and palate: effects on cleft width.

    PubMed

    de Jong, Johanna P; Breugem, Corstiaan C

    2014-05-01

    Although no universal consensus exists on treatment of cleft palates, early hard palate closure is commonly performed. The aim of the present study was to determine the influence of a vomer flap for early hard palate closure on residual palatal cleft width in patients with a unilateral complete cleft lip and palate (UCLP). Forty-seven UCLP patients were retrospectively divided into two groups. Group A consisted of 25 patients who underwent early lip closure and simultaneous hard palate closure using a vomer flap. Group B included 22 patients who had lip closure only at first surgery. Palatal cleft widths of both groups were measured at two time points and were compared using the Mann-Whitney U test to examine the influence of vomerplasty in this very early stage. No significant difference of baseline characteristics between the groups was found, and comparison of age at the time of surgeries was not significantly different. Mean age at the time of vomerplasty was 4.0 months. After the first surgery, a significantly greater total cleft width reduction of 5.0 mm average was found in group A compared to only 1.5 mm reduction in group B. This reduction took place after an average of 7.1 and 7.0 months, respectively. Lip closure accompanied by early hard palate closure using a vomer flap is associated with a significant postoperative reduction of the residual cleft when compared to lip closure only. This study shows another great advantage of performing early hard palate closure using a vomer flap.

  7. Novel FGFR1 and KISS1R Mutations in Chinese Kallmann Syndrome Males with Cleft Lip/Palate.

    PubMed

    Xu, Hao; Niu, Yonghua; Wang, Tao; Liu, Simin; Xu, Hua; Wang, Shaogang; Liu, Jihong; Ye, Zhangqun

    2015-01-01

    Kallmann syndrome (KS) is characterized by isolated hypogonadotropic hypogonadism (IHH) with anosmia and is sometimes associated with cleft lip/palate (CLP). In order to describe the clinical features, genetic etiology, and treatment outcome of KS males with CLP, we performed genetic screening for 15 known causal IHH genes (KAL1, FGFR1, NELF, FGF8, CHD7, WDR11, SEMA3A, KISS1R, KISS1, PROKR2, PROK2, TAC3, TACR3, GNRH1, and GNRHR) in four KS with CLP patients and six IHH patients without CLP. Two novel heterozygous missense mutations in FGFR1, (NM_001174066): c.776G>A (p.G259E) and (NM_001174066): c.358C>T (p.R120C), were identified in a 23-year-old KS male with cleft lip and an 18-year-old KS patient with cleft lip and palate, dental agenesis, and high arched palate, respectively. These two mutations were not presented in their healthy parents and 200 normal controls. One novel heterozygous missense mutation in KISS1R, (NM_032551): c.587C>A (p.P196H), was identified in an 18-year-old KS male with cleft lip and dental agenesis who developed sperm after being treated with gonadotropin. This mutation was also presented in his healthy father and grandfather. These results have implications for the diagnosis, genetic counseling, and treatment of KS and CLP males with mutations in FGFR1 gene.

  8. Shielding requirements in helical tomotherapy

    NASA Astrophysics Data System (ADS)

    Baechler, S.; Bochud, F. O.; Verellen, D.; Moeckli, R.

    2007-08-01

    Helical tomotherapy is a relatively new intensity-modulated radiation therapy (IMRT) treatment for which room shielding has to be reassessed for the following reasons. The beam-on-time needed to deliver a given target dose is increased and leads to a weekly workload of typically one order of magnitude higher than that for conventional radiation therapy. The special configuration of tomotherapy units does not allow the use of standard shielding calculation methods. A conventional linear accelerator must be shielded for primary, leakage and scatter photon radiations. For tomotherapy, primary radiation is no longer the main shielding issue since a beam stop is mounted on the gantry directly opposite the source. On the other hand, due to the longer irradiation time, the accelerator head leakage becomes a major concern. An analytical model based on geometric considerations has been developed to determine leakage radiation levels throughout the room for continuous gantry rotation. Compared to leakage radiation, scatter radiation is a minor contribution. Since tomotherapy units operate at a nominal energy of 6 MV, neutron production is negligible. This work proposes a synthetic and conservative model for calculating shielding requirements for the Hi-Art II TomoTherapy unit. Finally, the required concrete shielding thickness is given for different positions of interest.

  9. Shielding requirements in helical tomotherapy.

    PubMed

    Baechler, S; Bochud, F O; Verellen, D; Moeckli, R

    2007-08-21

    Helical tomotherapy is a relatively new intensity-modulated radiation therapy (IMRT) treatment for which room shielding has to be reassessed for the following reasons. The beam-on-time needed to deliver a given target dose is increased and leads to a weekly workload of typically one order of magnitude higher than that for conventional radiation therapy. The special configuration of tomotherapy units does not allow the use of standard shielding calculation methods. A conventional linear accelerator must be shielded for primary, leakage and scatter photon radiations. For tomotherapy, primary radiation is no longer the main shielding issue since a beam stop is mounted on the gantry directly opposite the source. On the other hand, due to the longer irradiation time, the accelerator head leakage becomes a major concern. An analytical model based on geometric considerations has been developed to determine leakage radiation levels throughout the room for continuous gantry rotation. Compared to leakage radiation, scatter radiation is a minor contribution. Since tomotherapy units operate at a nominal energy of 6 MV, neutron production is negligible. This work proposes a synthetic and conservative model for calculating shielding requirements for the Hi-Art II TomoTherapy unit. Finally, the required concrete shielding thickness is given for different positions of interest.

  10. Motion of multiple helical vortices

    NASA Astrophysics Data System (ADS)

    Velasco Fuentes, Oscar

    2015-11-01

    In 1912 Joukowsky deduced that in an unbounded ideal fluid a set of helical vortices--when these are equal, coaxial and symmetrically arranged--would translate and rotate steadily while the vortices preserve their form and relative position. Each vortex is an infinite tube whose cross-section is circular (with radius a) and whose centerline is a helix of pitch L and radius R. The motion is thus determined by three non-dimensional parameters only: the number of vortices N, the vortex radius α = a / R and the vortex pitch τ = L / 2 πR . Here, we express the linear and angular velocities of the vortices as the sum of the mutually induced velocities found by Okulov (2004) and the self-induced velocities found by Velasco Fuentes (2015). We verified that our results are accurate over the whole range of values of the vortices' pitch and radius by numerically computing the vortex motion with two smoothed versions of the Biot-Savart law. It was found that the translation velocity U grows with the number of vortices (N) but decreases as the vortices' radius and pitch (a and τ, respectively) increase; in contrast, the rotation velocity Ω grows with N and a but has a local minimum around τ = 1 for fixed values of N and a.

  11. The motion of helical vortices

    NASA Astrophysics Data System (ADS)

    Velasco Fuentes, Oscar

    2014-11-01

    We study the motion of a helical vortex in an inviscid, incompressible fluid of infinite extent. The vortex is a thin tube, of circular cross section and uniform vorticity, whose centerline is a helix of uniform pitch. Ever since Joukowsky (1912) deduced that this vortex is a steady solution of the Euler equations, numerous attempts have been made to compute its self-induced velocity. Here we use Hardin's (1982) solution for the velocity field in order to compute, for any pitch value, the linear and angular velocities of the vortex. Our formulas were verified by direct numerical integration of both the Biot-Savart and Helmholtz equations, and were also found to compare favourably with previous theoretical results. In terms of the vortex capacity to transport fluid, we identified three regimes: a helix of large pitch moves slowly, carrying a large mass of fluid; a thin helix of small pitch moves fast, carrying a small mass of fluid; and a fat helix of small pitch is a moderate carrier itself but it pushes fluid forward along its axis.

  12. Helical modes in boundary layer transition

    NASA Astrophysics Data System (ADS)

    Bose, Rikhi; Durbin, Paul A.

    2016-11-01

    Observations are presented to show that in an adverse pressure gradient boundary layer, beneath free-stream turbulence, the interaction between Klebanoff streaks and naturally arising instability waves leads to helical disturbances which break down to form turbulent spots. This occurs under low to moderate levels, 1%-2%, of free-stream turbulence. At high levels of free-stream turbulence, conventional bypass mechanisms are seen. The helical structures are clearly identifiable in visualizations of isosurfaces of streamwise perturbation velocity. A direct numerical simulation also was performed in zero pressure gradient, with a time-periodic Tollmien-Schlichting wave eigenfunction at the inlet. Again, under a moderate level of free-stream turbulence, helices were observed, and found to trigger transition. Their wave speed is on the order of 1/2 U∞ , so helical breakdown can be viewed as a type of inner mode, secondary instability.

  13. The anisotropy of kinetic and current helicity

    NASA Astrophysics Data System (ADS)

    Reshetnyak, M. Yu.

    2017-09-01

    A three-dimensional model for thermal convection with a dynamo in a rotating planar layer heated from below is used to investigate the behavior of the mean kinetic and current helicities. In spite of the presence of gravity and rotation, which introduce anisotropy into the system, the components of the helicity determined from the field components in the directions tangent and normal to the boundary have similar values. The existence of a separation by scale, when the current helicity has different signs on different spatial scales, is demonstrated. The number of regions where the sign of the helicity does not coincide with the sign of its mean value in that region is estimated (˜43-45% of the total number of regions). The estimates presented are relevant for interpretations of observations of solar activity and analysis of the properties of rotating magnetohydrodynamical turbulence.

  14. Microfluidic Lithography of Bioinspired Helical Micromotors.

    PubMed

    Yu, Yunru; Shang, Luoran; Gao, Wei; Zhao, Ze; Wang, Huan; Zhao, Yuanjin

    2017-07-29

    Considerable efforts have been devoted to developing artificial micro/nanomotors that can convert energy into movement. A flow lithography integrated microfluidic spinning and spiraling system is developed for the continuous generation of bioinspired helical micromotors. Because the generation processes could be precisely tuned by adjusting the flow rates and the illuminating frequency, the length, diameter, and pitch of the helical micromotors were highly controllable. Benefiting from the fast online gelation and polymerization, the resultant helical micromotors could be imparted with Janus, triplex, and core-shell cross-sectional structures that have never been achieved by other methods. Owing to the spatially controlled encapsulation of functional nanoparticles in the microstructures, the helical micromotors can perform locomotion not only by magnetically actuated rotation or corkscrew motion but also through chemically powered catalytic reaction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Helical Microfilaments with Alternating Imprinted Intrinsic Curvatures.

    PubMed

    Silva, Pedro Emanuel Santos; Godinho, Maria Helena

    2017-03-01

    There has been an intense research for developing techniques that can produce filaments with helical shapes, given the widespread of potential applications. In this work, how helices with different curvatures can be precisely imprinted in microfilaments is shown. It is also shown that using this technique, it is possible to produce, in a single fiber, helices with different curvatures. This striking and innovative behavior is observed when one side of the stretched filaments is irradiated with UV light, modifying the mechanical properties at surface. Upon release, the regions with higher curvature start to curl first, while regions with lower intrinsic curvature remain stretched until start to curl later. The results presented here can be important to understand why structures adopt a helical shape in general, which can be of interest in nanotechnology, biomolecular science, or even to understand why plant filaments curl. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Helical vortices: viscous dynamics and instability

    NASA Astrophysics Data System (ADS)

    Rossi, Maurice; Selcuk, Can; Delbende, Ivan; Ijlra-Upmc Team; Limsi-Cnrs Team

    2014-11-01

    Understanding the dynamical properties of helical vortices is of great importance for numerous applications such as wind turbines, helicopter rotors, ship propellers. Locally these flows often display a helical symmetry: fields are invariant through combined axial translation of distance Δz and rotation of angle θ = Δz / L around the same z-axis, where 2 πL denotes the helix pitch. A DNS code with built-in helical symmetry has been developed in order to compute viscous quasi-steady basic states with one or multiple vortices. These states will be characterized (core structure, ellipticity, ...) as a function of the pitch, without or with an axial flow component. The instability modes growing in the above base flows and their growth rates are investigated by a linearized version of the DNS code coupled to an Arnoldi procedure. This analysis is complemented by a helical thin-cored vortex filaments model. ANR HELIX.

  17. Scaling laws in decaying helical hydromagnetic turbulence

    NASA Astrophysics Data System (ADS)

    Christensson, M.; Hindmarsh, M.; Brandenburg }%, A.

    2005-07-01

    We study the evolution of growth and decay laws for the magnetic field coherence length ξ, energy E_M and magnetic helicity H in freely decaying 3D MHD turbulence. We show that with certain assumptions, self-similarity of the magnetic power spectrum alone implies that ξ σm t1/2. This in turn implies that magnetic helicity decays as Hσm t-2s, where s=(ξ_diff/ξH)2, in terms of ξ_diff, the diffusion length scale, and ξ_H, a length scale defined from the helicity power spectrum. The relative magnetic helicity remains constant, implying that the magnetic energy decays as E_M σm t-1/2-2s. The parameter s is inversely proportional to the magnetic Reynolds number Re_M, which is constant in the self-similar regime.

  18. Emergence of helicity in rotating stratified turbulence

    NASA Astrophysics Data System (ADS)

    Marino, Raffaele; Mininni, Pablo D.; Rosenberg, Duane; Pouquet, Annick

    2013-03-01

    We perform numerical simulations of decaying rotating stratified turbulence and show, in the Boussinesq framework, that helicity (velocity-vorticity correlation), as observed in supercell storms and hurricanes, is spontaneously created due to an interplay between buoyancy and rotation common to large-scale atmospheric and oceanic flows. Helicity emerges from the joint action of eddies and of inertia-gravity waves (with inertia and gravity with respective associated frequencies f and N), and it occurs when the waves are sufficiently strong. For N/f<3 the amount of helicity produced is correctly predicted by a quasilinear balance equation. Outside this regime, and up to the highest Reynolds number obtained in this study, namely Re≈10000, helicity production is found to be persistent for N/f as large as ≈17, and for ReFr2 and ReRo2, respectively, as large as ≈100 and ≈24000.

  19. Building blocks for subleading helicity operators

    DOE PAGES

    Kolodrubetz, Daniel W.; Moult, Ian; Stewart, Iain W.

    2016-05-24

    On-shell helicity methods provide powerful tools for determining scattering amplitudes, which have a one-to-one correspondence with leading power helicity operators in the Soft-Collinear Effective Theory (SCET) away from singular regions of phase space. We show that helicity based operators are also useful for enumerating power suppressed SCET operators, which encode subleading amplitude information about singular limits. In particular, we present a complete set of scalar helicity building blocks that are valid for constructing operators at any order in the SCET power expansion. In conclusion, we also describe an interesting angular momentum selection rule that restricts how these building blocks canmore » be assembled.« less

  20. Dissecting π-helices: sequence, structure and function.

    PubMed

    Kumar, Prasun; Bansal, Manju

    2015-11-01

    A new procedure for the identification of regular secondary structures using a C(α) trace has identified 659 π-helices in 3582 protein chains, solved at high resolution. Taking advantage of this significantly expanded database of π-helices, we have analysed the functional and structural roles of π-helices and determined the position-wise amino acid propensity within and around them. These helices range from 5 to 18 residues in length with the average twist and rise being 85.2 ± 7.2° and 1.28 ± 0.31 Å, respectively. A total of 546 (~ 83%) out of 659 π-helices occur in conjunction with α-helices, with 101 π-helices being interspersed between two α-helices. The majority of interspersed π-helices were found to be conserved across a large number of structures within a protein family and produce a significant bend in the overall helical segment as well as local distortions in the neighbouring α-helices. The presence of a π-helical fragment leads to appropriate orientation of the constituent residues, so as to facilitate favourable interactions and also help in proper folding of the protein chain. In addition to intra helical 6→1 N-H···O hydrogen bonds, π-helices are also stabilized by several other non-bonded interactions. π-Helices show distinct positional residue preferences, which are different from those of α-helices.

  1. The Palatal and Oral Manifestations of Muenke Syndrome (FGFR3 related craniosynostosis)

    PubMed Central

    Agochukwu, Nneamaka B.; Solomon, Benjamin D.; Doherty, Emily S.; Muenke, Maximilian

    2012-01-01

    Palatal anomalies including cleft palate and higharched palate have been reported in the most common craniosynostosis syndromes, including Pfeiffer syndrome (associated with mutations in FGFR1, FGFR2), Apert syndrome (FGFR2), Muenke syndrome (FGFR3) and Crouzon syndrome (FGFR2). Although Muenke syndrome is the most common syndromic form of craniosynostosis, the frequency of oral and palatal anomalies including high arched palate, cleft lip with or without cleft palate has not been documented in a patient series of Muenke syndrome to date. Further, to our knowledge, cleft lip and palate has not been reported yet in a patient with Muenke syndrome (a previous patient with isolated cleft palate has been reported). This study sought to evaluate the frequency of palatal anomalies in patients with Muenke syndrome through both a retrospective investigation and literature review. A total of 21 patients who met criteria for this study were included in the retrospective review. 15 patients (71%) had a structural anomaly of the palate. Cleft lip and palate was present in one patient (5%). Other palatal findings included: high arched hard palate in 14 patients (67%). Individuals with Muenke syndrome have the lowest incidence of cleft palate among the most common craniosynostosis syndromes. However, high arched palate in Muenke syndrome is common and may warrant clinical attention, as these individuals are more susceptible to recurrent chronic otitis media with effusion, dental malocclusion and hearing loss. PMID:22565872

  2. Sprouty2 controls proliferation of palate mesenchymal cells via fibroblast growth factor signaling

    SciTech Connect

    Matsumura, Kaori; Taketomi, Takaharu; Yoshizaki, Keigo; Arai, Shinsaku; Sanui, Terukazu; Yoshiga, Daigo; Yoshimura, Akihiko; Nakamura, Seiji

    2011-01-28

    Research highlights: {yields} Sprouty2-deficient mice exhibit cleft palate as a result of failure of palatal shelf elevation. {yields} We examined palate cell proliferation in Sprouty2-deficient mice. {yields} Palate mesenchymal cell proliferation was increased in Sprouty2 KO mice. {yields} Sprouty2 plays roles in murine palatogenesis by regulating cell proliferation. -- Abstract: Cleft palate is one of the most common craniofacial deformities. The fibroblast growth factor (FGF) plays a central role in reciprocal interactions between adjacent tissues during palatal development, and the FGF signaling pathway has been shown to be inhibited by members of the Sprouty protein family. In this study, we report the incidence of cleft palate, possibly caused by failure of palatal shelf elevation, in Sprouty2-deficient (KO) mice. Sprouty2-deficient palates fused completely in palatal organ culture. However, palate mesenchymal cell proliferation estimated by Ki-67 staining was increased in Sprouty2 KO mice compared with WT mice. Sprouty2-null palates expressed higher levels of FGF target genes, such as Msx1, Etv5, and Ptx1 than WT controls. Furthermore, proliferation and the extracellular signal-regulated kinase (Erk) activation in response to FGF was enhanced in palate mesenchymal cells transfected with Sprouty2 small interfering RNA. These results suggest that Sprouty2 regulates palate mesenchymal cell proliferation via FGF signaling and is involved in palatal shelf elevation.

  3. CURRENT HELICITY OF ACTIVE REGIONS AS A TRACER OF LARGE-SCALE SOLAR MAGNETIC HELICITY

    SciTech Connect

    Zhang, H.; Gao, Y.; Xu, H.; Moss, D.; Kleeorin, N.; Rogachevskii, I.; Kuzanyan, K.; Sokoloff, D.

    2012-05-20

    We demonstrate that the current helicity observed in solar active regions traces the magnetic helicity of the large-scale dynamo generated field. We use an advanced two-dimensional mean-field dynamo model with dynamo saturation based on the evolution of the magnetic helicity and algebraic quenching. For comparison, we also studied a more basic two-dimensional mean-field dynamo model with simple algebraic alpha-quenching only. Using these numerical models we obtained butterfly diagrams both for the small-scale current helicity and also for the large-scale magnetic helicity, and compared them with the butterfly diagram for the current helicity in active regions obtained from observations. This comparison shows that the current helicity of active regions, as estimated by -A {center_dot} B evaluated at the depth from which the active region arises, resembles the observational data much better than the small-scale current helicity calculated directly from the helicity evolution equation. Here B and A are, respectively, the dynamo generated mean magnetic field and its vector potential. A theoretical interpretation of these results is given.

  4. Impact of new technologies on dose reduction in CT.

    PubMed

    Lee, Ting-Yim; Chhem, Rethy K

    2010-10-01

    The introduction of slip ring technology enables helical CT scanning in the late 1980's and has rejuvenated CT's role in diagnostic imaging. Helical CT scanning has made possible whole body scanning in a single breath hold and computed tomography angiography (CTA) which has replaced invasive catheter based angiography in many cases because of its easy of operation and lesser risk to patients. However, a series of recent articles and accidents have heightened the concern of radiation risk from CT scanning. Undoubtedly, the radiation dose from CT studies, in particular, CCTA studies, are among the highest dose studies in diagnostic imaging. Nevertheless, CT has remained the workhorse of diagnostic imaging in emergent and non-emergent situations because of their ubiquitous presence in medical facilities from large academic to small regional hospitals and their round the clock accessibility due to their ease of use for both staff and patients as compared to MR scanners. The legitimate concern of radiation dose has sparked discussions on the risk vs benefit of CT scanning. It is recognized that newer CT applications, like CCTA and perfusion, will be severely curtailed unless radiation dose is reduced. This paper discusses the various hardware and software techniques developed to reduce radiation dose to patients in CT scanning. The current average effective dose of a CT study is ∼10 mSv, with the implementation of dose reduction techniques discussed herein; it is realistic to expect that the average effective dose may be decreased by 2-3 fold. Copyright © 2010. Published by Elsevier Ireland Ltd.

  5. Effects of variation in the timing of palatal repair on sagittal craniofacial morphology in complete cleft lip and palate children.

    PubMed

    Nandlal; Utreja, A; Tewari, A; Chari, P S

    2000-12-01

    The complete cleft lip and palate children, ranging from 6-14 years of age were studied to evaluate the effect of variation in the timing of palatal repair on craniofacial morphology and compared to the noncleft children. It was observed that all the groups early (8 to < or = 24 months), medium (> 24 to < or = 36 months) and late repair (> 36 to < or = 78 months) had significantly larger cranial base, retruded maxillomandibular relations, skeletodental and incisal relationships compared to the noncleft children. However, intercomparison among the cleft groups showed insignificant difference amongst them suggesting that the timing of palatal repairs does not effect the anterioposterior (sagittal) relationship.

  6. Decay of helical and nonhelical magnetic knots

    NASA Astrophysics Data System (ADS)

    Candelaresi, Simon; Brandenburg, Axel

    2011-07-01

    We present calculations of the relaxation of magnetic field structures that have the shape of particular knots and links. A set of helical magnetic flux configurations is considered, which we call n-foil knots of which the trefoil knot is the most primitive member. We also consider two nonhelical knots; namely, the Borromean rings as well as a single interlocked flux rope that also serves as the logo of the Inter-University Centre for Astronomy and Astrophysics in Pune, India. The field decay characteristics of both configurations is investigated and compared with previous calculations of helical and nonhelical triple-ring configurations. Unlike earlier nonhelical configurations, the present ones cannot trivially be reduced via flux annihilation to a single ring. For the n-foil knots the decay is described by power laws that range form t-2/3 to t-1/3, which can be as slow as the t-1/3 behavior for helical triple-ring structures that were seen in earlier work. The two nonhelical configurations decay like t-1, which is somewhat slower than the previously obtained t-3/2 behavior in the decay of interlocked rings with zero magnetic helicity. We attribute the difference to the creation of local structures that contain magnetic helicity which inhibits the field decay due to the existence of a lower bound imposed by the realizability condition. We show that net magnetic helicity can be produced resistively as a result of a slight imbalance between mutually canceling helical pieces as they are being driven apart. We speculate that higher order topological invariants beyond magnetic helicity may also be responsible for slowing down the decay of the two more complicated nonhelical structures mentioned above.

  7. Helical rotary screw expander power system

    NASA Technical Reports Server (NTRS)

    Mckay, R. A.; Sprankle, R. S.

    1974-01-01

    An energy converter for the development of wet steam geothermal fields is described. A project to evaluate and characterize a helical rotary screw expander for geothermal applications is discussed. The helical screw expander is a positive displacement machine which can accept untreated corrosive mineralized water of any quality from a geothermal well. The subjects of corrosion, mineral deposition, the expansion process, and experience with prototype devices are reported.

  8. RF Pulse Compression Using Helically Corrugated Waveguides

    NASA Astrophysics Data System (ADS)

    MacInnes, P.; Ronald, K.; Burt, G.; Cross, A. W.; Young, A. R.; Phelps, A. D. R.; Konoplev, I. V.; He, W.; Samsonov, S. V.; Bratman, V. L.; Denisov, G. G.

    2006-01-01

    This paper describes the use of a helically corrugated waveguide as a dispersive medium for microwave pulse compression. The helically corrugated waveguide has a large variation of group velocity with frequency, but in a region where the group velocity remains large. Therefore this compressor does not suffer from reflections associated with cut-off scenarios at frequencies close to its operating regime and may be used in conjunction with high power wideband tunable microwave sources and amplifiers.

  9. On the stability of multiple helical vortices

    NASA Astrophysics Data System (ADS)

    Okulov, V. L.

    2004-12-01

    The classical problem of linear stability of a regular N-gon of point vortices to infinitesimal space displacements from an equilibrium of the vortex configuration is generalized to the one for N helical vortices (couple, triplet, etc., N {>} 1) for the first time. As a consequence of this consideration, the analytical form for the stability boundaries has been obtained. This solution allows an efficient analysis to be made of the existence of stable helical vortex arrays, which were repeatedly observed in practice.

  10. Influence of initial mean helicity on homogeneous turbulent shear flow.

    PubMed

    Jacobitz, Frank G; Schneider, Kai; Bos, Wouter J T; Farge, Marie

    2011-11-01

    Helicity statistics are studied in homogeneous turbulent shear flow. Initial mean helicity is imposed on an isotropic turbulence field using a decomposition of the flow into complex-valued helical waves. The initial decay of the turbulent kinetic energy is weakened in the presence of strong mean helicity, consistent with an analytic analysis of the spectral tensor of velocity correlations. While exponential growth of the mean turbulent kinetic energy is obtained, the mean helicity decays. Probability distribution functions (PDFs) of helicity are skewed and show that the imposed mean helicity prevails throughout the simulations. A wavelet-based scale-dependent analysis shows a trend to two dimensionalization for large scales of motion and a preference for helical motion at small scales. The magnitude of the skewness of the PDFs decreases for smaller scales. Joint PDFs indicate a strong correlation of the signs of both, helicity and superhelicity, for all cases. This correlation supports the conjecture that superhelicity dissipates helicity.

  11. Complete measurement of helicity and its dynamics in vortex tubes

    NASA Astrophysics Data System (ADS)

    Scheeler, Martin W.; van Rees, Wim M.; Kedia, Hridesh; Kleckner, Dustin; Irvine, William T. M.

    2017-08-01

    Helicity, a topological measure of the intertwining of vortices in a fluid flow, is a conserved quantity in inviscid fluids but can be dissipated by viscosity in real flows. Despite its relevance across a range of flows, helicity in real fluids remains poorly understood because the entire quantity is challenging to measure. We measured the total helicity of thin-core vortex tubes in water. For helical vortices that are stretched or compressed by a second vortex, we found conservation of total helicity. For an isolated helical vortex, we observed evolution toward and maintenance of a constant helicity state after the dissipation of twist helicity by viscosity. Our results show that helicity can remain constant even in a viscous fluid and provide an improved basis for understanding and manipulating helicity in real flows.

  12. Liquid crystal helical ribbons as isometric textures

    NASA Astrophysics Data System (ADS)

    Achard, M.-F.; Kleman, M.; Nastishin, Yu. A.; Nguyen, H.-T.

    2005-01-01

    Deformations that conserve the parallelism and the distances between layers, in smectic phases; between columns, in columnar phases are commonplace in liquid crystals. The resulting isometric deformed textures display specific geometric features. The corresponding order parameter singularities extend over rather large, macroscopic, distances, e.g., cofocal conics in smectics. This well-known picture is modified when, superimposed to the 1D or 2D periodicities, the structure is helical. However isometry can be preserved. This paper discusses the case of a medium whose structure is made of 1D modulated layers (a lamello-columnar phase), assuming that the modulations rotate helically from one layer to the next. The price to pay is that any isometric texture is necessarily frustrated; it consists of layers folded into a set of parallel helicoids, in the manner of a screw dislocation (of macroscopic Burgers vector), the modulations being along the helices, i.e. double-twisted. The singularity set is made of two helical disclination lines. We complete this geometric analysis by a crude calculation of the energy of a helical ribbon. It is suggested that the helical ribbons observed in the B7 phase of banana-like molecules are such isometric textures. As a side result, let us mention that the description of double-twist, traditionally made in terms of a partition of the director field into nested cylinders, could more than often be profitably tested against a partition into nested helicoids.

  13. Filament Channel Formation Via Magnetic Helicity Condensation

    NASA Astrophysics Data System (ADS)

    Knizhnik, Kalman Joshua; Antiochos, Spiro K.; DeVore, C. Richard

    2015-04-01

    A major unexplained feature of the solar atmosphere is the accumulation of magnetic shear, in the form of filament channels, at photospheric polarity inversion lines (PILs). In addition to free energy, this shear also represents magnetic helicity, which is conserved under reconnection. In this work, we address the problem of filament channel formation and show how they acquire their shear and magnetic helicity. The results of 3D simulations using the Adaptively Refined Magnetohydrodynamics Solver (ARMS) are presented that support the model of filament channel formation by magnetic helicity condensation developed by Antiochos (2013). We consider the convective twisting of a quasi-potential flux system that is bounded by a PIL and contains a coronal hole (CH). The magnetic helicity injected by the small-scale photospheric motions is shown to inverse-cascade up to the largest allowable scales that defined the closed flux system: the PIL and the CH. This process produces field lines that are both sheared and smooth, and are sheared in opposite senses at the PIL and the CH. The accumulated helicity and shear flux are shown to be in excellent quantitative agreement with the helicity-condensation model. We present a detailed analysis of the simulations, including comparisons of our analytical and numerical results, and discuss their implications for observations. Our research was supported by NASA's Earth and Space Science Fellowship (K.J.K.) and Heliophysics Supporting Research (S.K.A. and C.R.D.) programs.

  14. Filament Channel Formation via Magnetic Helicity Condensation

    NASA Astrophysics Data System (ADS)

    Knizhnik, K. J.; Antiochos, S. K.; DeVore, C. R.

    2015-08-01

    A major unexplained feature of the solar atmosphere is the accumulation of magnetic shear in the form of filament channels at photospheric polarity inversion lines (PILs). In addition to free energy, this shear represents magnetic helicity, which is conserved under reconnection. In this paper we address the problem of filament channel formation and show how filaments acquire their shear and magnetic helicity. The results of three-dimensional (3D) simulations using the Adaptively Refined Magnetohydrodynamics Solver are presented. Our findings support the model of filament channel formation by magnetic helicity condensation that was developed by Antiochos. We consider the small-scale photospheric twisting of a quasi-potential flux system that is bounded by a PIL and contains a coronal hole (CH). The magnetic helicity injected by the small-scale photospheric motions is shown to inverse cascade up to the largest allowable scales that define the closed flux system: the PIL and the CH. This process produces field lines that are both sheared and smooth, and are sheared in opposite senses at the PIL and the CH. The accumulated helicity and shear flux are shown to be in excellent quantitative agreement with the helicity condensation model. We present a detailed analysis of the simulations, including comparisons of our analytical and numerical results, and discuss their implications for observations.

  15. The AGS with four helical magnets

    SciTech Connect

    Tsoupas, N.; Huang, H.; MacKay, W.W.; Roser, T.; Trbojevic, D.

    2010-02-25

    The idea of using multiple partial helical magnets was applied successfully to the AGS synchrotron, to preserve the proton beam polarization. In this paper we explore in details the idea of using four helical magnets placed symmetrically in the AGS ring. This modification provides many advantages over the present setup of the AGS that uses two partial helical magnets. First, it provides a larger 'spin tune gap' for the placement of the vertical betatron tune of the AGS during acceleration, second, the vertical spin direction during the beam injection and extraction is closer to vertical, third, the symmetric placement of the snakes allows for a better control of the AGS optics, and for reduced values of the beta and eta functions, especially near injection, fourth, the optical properties of the helical magnets also favor the placement of the horizontal betatron tune in the 'spin tune gap', thus eliminating the horizontal spin resonances. In this paper we provide results on the spin tune and on the optics of the AGS with four partial helical magnets, and we compare these results with the present setup of the AGS that uses two partial helical magnets.

  16. MHD Gauge Fields: Helicities and Casimirs

    NASA Astrophysics Data System (ADS)

    Hu, Q.; Webb, G. M.; Zank, G. P.; Anco, S.

    2016-12-01

    Clebsch potential gauge field theory for magnetohydrodynamics is developed based in part on the theory of Calkin (1963). It is shown how the polarization vector P in Calkin's approach, naturally arises from the Lagrange multiplier constraint equation for Faraday's equation for the magnetic induction B, or alternatively from the magnetic vector potential form of Faraday's equation. Gauss's equation, (divergence of Bis zero), is incorporated in the variational principle by means of a Lagrange multiplier constraint. Noether's theorem, and gauge symmetries are used to derive the conservation laws for (a) magnetic helicity (b) cross helicity, (c) fluid helicity for non-magnetized fluids, and (d) a class of conservation laws associated with curl and divergence equations, which applies to Faraday's equation and Gauss's equation. The magnetic helicity conservation law is due to a gauge symmetry in MHD and not due to a fluid relabelling symmetry. The analysis is carried out for a non-barotropic gas. The cross helicity and fluid helicity conservation are nonlocal conservation laws, that reduce to local conservation laws for the case of a barotropic gas. The connections between gauge symmetries, Clebsch potentials and Casimirs are developed. It is shown that the gauge symmetry functionals in the work of Henyey (1982) satisfy the Casimir equations.

  17. Helicity Annihilation in Trefoil Reconnection: Simulations

    NASA Astrophysics Data System (ADS)

    Kerr, Robert M.

    2015-11-01

    The simulated evolution and self-reconnection of a perturbed trefoil vortex knot is compared to the experiment. To have a single initial reconnection, as in the experiments, the trefoil is perturbed by 4 weak vortex rings. Visualizations show that the simulations and experiments undergo similar topological changes. Quantitative comparisons using the helicity and global topological number show that both are preserved for a long period before reconnection begins, as in the experiments. Unlike the experiments, once reconnection begins, a significant fraction of the helicity is dissipated and the global topological number changes by a discrete amount in a fixed time. Helicity spectra and physical space correlations show that the change in helicity is associated with the appearance of negative helicity at lower wavenumbers and in the outer regions of the trefoil. Furthermore, using a range of Reynolds numbers, with the highest comparable to the experiments, it is demonstrated that a Reynolds number independent fraction of the initial helicity is dissipated in a finite time. This observation does not violate any current mathematics restricting the strong growth of Navier-Stokes norms as the viscosity goes to zero due to the structure of the trefoil.

  18. On the helicity of open magnetic fields

    SciTech Connect

    Prior, C.; Yeates, A. R.

    2014-06-01

    We reconsider the topological interpretation of magnetic helicity for magnetic fields in open domains, and relate this to the relative helicity. Specifically, our domains stretch between two parallel planes, and each of these ends may be magnetically open. It is demonstrated that, while the magnetic helicity is gauge-dependent, its value in any gauge may be physically interpreted as the average winding number among all pairs of field lines with respect to some orthonormal frame field. In fact, the choice of gauge is equivalent to the choice of reference field in the relative helicity, meaning that the magnetic helicity is no less physically meaningful. We prove that a particular gauge always measures the winding with respect to a fixed frame, and propose that this is normally the best choice. For periodic fields, this choice is equivalent to measuring relative helicity with respect to a potential reference field. However, for aperiodic fields, we show that the potential field can be twisted. We prove by construction that there always exists a possible untwisted reference field.

  19. Bioinspired helical microswimmers based on vascular plants.

    PubMed

    Gao, Wei; Feng, Xiaomiao; Pei, Allen; Kane, Christopher R; Tam, Ryan; Hennessy, Camille; Wang, Joseph

    2014-01-08

    Plant-based bioinspired magnetically propelled helical microswimmers are described. The helical microstructures are derived from spiral water-conducting vessels of different plants, harnessing the intrinsic biological structures of nature. Geometric variables of the spiral vessels, such as the helix diameter and pitch, can be controlled by mechanical stretching for the precise fabrication and consistent performance of helical microswimmers. Xylem vessels of a wide variety of different plants have been evaluated for the consistency and reproducibility of their helical parameters. Sequential deposition of thin Ti and Ni layers directly on the spiral vessels, followed by dicing, leads to an extremely simple and cost-efficient mass-production of functional helical microswimmers. The resulting plant-based magnetic microswimmers display efficient propulsion, with a speed of over 250 μm/s, as well as powerful locomotion in biological media such as human serum. The influence of actuation frequencies on the swimming velocity is investigated. Such use of plant vessels results in significant savings in the processing costs and provides an extremely simple, cost-effective fabrication route for the large-scale production of helical magnetic swimmers.

  20. FILAMENT CHANNEL FORMATION VIA MAGNETIC HELICITY CONDENSATION

    SciTech Connect

    Knizhnik, K. J.; Antiochos, S. K.; DeVore, C. R.

    2015-08-20

    A major unexplained feature of the solar atmosphere is the accumulation of magnetic shear in the form of filament channels at photospheric polarity inversion lines (PILs). In addition to free energy, this shear represents magnetic helicity, which is conserved under reconnection. In this paper we address the problem of filament channel formation and show how filaments acquire their shear and magnetic helicity. The results of three-dimensional (3D) simulations using the Adaptively Refined Magnetohydrodynamics Solver are presented. Our findings support the model of filament channel formation by magnetic helicity condensation that was developed by Antiochos. We consider the small-scale photospheric twisting of a quasi-potential flux system that is bounded by a PIL and contains a coronal hole (CH). The magnetic helicity injected by the small-scale photospheric motions is shown to inverse cascade up to the largest allowable scales that define the closed flux system: the PIL and the CH. This process produces field lines that are both sheared and smooth, and are sheared in opposite senses at the PIL and the CH. The accumulated helicity and shear flux are shown to be in excellent quantitative agreement with the helicity condensation model. We present a detailed analysis of the simulations, including comparisons of our analytical and numerical results, and discuss their implications for observations.

  1. Computational Embryology and Predictive Toxicology of Cleft Palate

    EPA Science Inventory

    Capacity to model and simulate key events in developmental toxicity using computational systems biology and biological knowledge steps closer to hazard identification across the vast landscape of untested environmental chemicals. In this context, we chose cleft palate as a model ...

  2. Computational Embryology and Predictive Toxicology of Cleft Palate

    EPA Science Inventory

    Capacity to model and simulate key events in developmental toxicity using computational systems biology and biological knowledge steps closer to hazard identification across the vast landscape of untested environmental chemicals. In this context, we chose cleft palate as a model ...

  3. Putative functions of extracellular matrix glycoproteins in secondary palate morphogenesis

    PubMed Central

    d'Amaro, Rocca; Scheidegger, Rolf; Blumer, Susan; Pazera, Pawel; Katsaros, Christos; Graf, Daniel; Chiquet, Matthias

    2012-01-01

    Cleft palate is a common birth defect in humans. Elevation and fusion of paired palatal shelves are coordinated by growth and transcription factors, and mutations in these can cause malformations. Among the effector genes for growth factor signaling are extracellular matrix (ECM) glycoproteins. These provide substrates for cell adhesion (e.g., fibronectin, tenascins), but also regulate growth factor availability (e.g., fibrillins). Cleft palate in Bmp7 null mouse embryos is caused by a delay in palatal shelf elevation. In contrast, palatal shelves of Tgf-β3 knockout mice elevate normally, but a cleft develops due to their failure to fuse. However, nothing is known about a possible functional interaction between specific ECM proteins and Tgf-β/Bmp family members in palatogenesis. To start addressing this question, we studied the mRNA and protein distribution of relevant ECM components during secondary palate development, and compared it to growth factor expression in wildtypewild type and mutant mice. We found that fibrillin-2 (but not fibrillin-1) mRNA appeared in the mesenchyme of elevated palatal shelves adjacent to the midline epithelial cells, which were positive for Tgf-β3 mRNA. Moreover, midline epithelial cells started expressing fibronectin upon contact of the two palatal shelves. These findings support the hypothesis that fibrillin-2 and fibronectin are involved in regulating the activity of Tgf-β3 at the fusing midline. In addition, we observed that tenascin-W (but not tenascin-C) was misexpressed in palatal shelves of Bmp7-deficient mouse embryos. In contrast to tenascin-C, tenascin-W secretion was strongly induced by Bmp7 in embryonic cranial fibroblasts in vitro. These results are consistent with a putative function for tenascin-W as a target of Bmp7 signaling during palate elevation. Our results indicate that distinct ECM proteins are important for morphogenesis of the secondary palate, both as downstream effectors and as regulators of Tgf

  4. Alternative Methods for Field Corrections in Helical Solenoids

    SciTech Connect

    Lopes, M. L.; Krave, S. T.; Tompkins, J. C.; Yonehara, K.; Flanagan, G.; Kahn, S. A.; Melconian, K.

    2015-05-01

    Helical cooling channels have been proposed for highly efficient 6D muon cooling. Helical solenoids produce solenoidal, helical dipole, and helical gradient field components. Previous studies explored the geometric tunability limits on these main field components. In this paper we present two alternative correction schemes, tilting the solenoids and the addition of helical lines, to reduce the required strength of the anti-solenoid and add an additional tuning knob.

  5. [Cleft lip and palate--problematic cleft speech].

    PubMed

    Hortis-Dzierzbicka, M A

    1999-01-01

    The early restoration of facial and palatal morphology in patients with cleft of lip and/or palate provides the anatomical base for good speech outcome. The author gives the up todate overview of the main problems concerning cleft speech, such as velopalatal insufficiency and typical articulation errors. The article describes the modern methods for the evaluation of VPI and current trends in treatment modalities for VPI.

  6. Dislocated Tongue Muscle Attachment and Cleft Palate Formation.

    PubMed

    Kouskoura, T; El Fersioui, Y; Angelini, M; Graf, D; Katsaros, C; Chiquet, M

    2016-04-01

    In Pierre Robin sequence, a retracted tongue due to micrognathia is thought to physically obstruct palatal shelf elevation and thereby cause cleft palate. However, micrognathia is not always associated with palatal clefting. Here, by using the Bmp7-null mouse model presenting with cleft palate and severe micrognathia, we provide the first causative mechanism linking the two. In wild-type embryos, the genioglossus muscle, which mediates tongue protrusion, originates from the rostral process of Meckel's cartilage and later from the mandibular symphysis, with 2 tendons positive for Scleraxis messenger RNA. In E13.5 Bmp7-null embryos, a rostral process failed to form, and a mandibular symphysis was absent at E17.5. Consequently, the genioglossus muscle fibers were diverted toward the lingual surface of Meckel's cartilage and mandibles, where they attached in an aponeurosis that ectopically expressed Scleraxis. The deflection of genioglossus fibers from the anterior-posterior toward the medial-lateral axis alters their direction of contraction and necessarily compromises tongue protrusion. Since this muscle abnormality precedes palatal shelf elevation, it is likely to contribute to clefting. In contrast, embryos with a cranial mesenchyme-specific deletion of Bmp7 (Bmp7:Wnt1-Cre) exhibited some degree of micrognathia but no cleft palate. In these embryos, a rostral process was present, indicating that mesenchyme-derived Bmp7 is dispensable for its formation. Moreover, the genioglossus appeared normal in Bmp7:Wnt1-Cre embryos, further supporting a role of aberrant tongue muscle attachment in palatal clefting. We thus propose that in Pierre Robin sequence, palatal shelf elevation is not impaired simply by physical obstruction by the tongue but by a specific developmental defect that leads to functional changes in tongue movements. © International & American Associations for Dental Research 2015.

  7. Orthognathic surgery in the cleft lip and palate patient.

    PubMed

    Herber, S C; Lehman, J A

    1993-10-01

    Orthognathic surgery for the cleft lip and palate patient should be designed to achieve good facial aesthetics and a stable, functional occlusion. Maxillary and mandibular osteotomies, which benefit cleft lip and palate patients with associated dentofacial deformities, should be modified to meet the needs of the individual patient. Soft-tissue correction of the upper lip and nose adds to the overall aesthetic result, but should be performed as a separate procedure.

  8. Postsurgical use of prosthetic palatal appliances. Two case reports.

    PubMed

    Artopoulou, Ioli-Ioanna; Higuera, Stephen; Martin, Jack W; Stal, Samuel; Chambers, Mark S

    2005-01-01

    Patients with cleft lip or palate encounter a myriad of difficulties in their early years of life, some of which begin at birth. The defect often impairs suckling and deglutition in the neonate. It can hinder appropriate speech development and may impose undue social and psychological stresses. Surgical and orthodontic interventions are essential and prosthetic palatal appliances play an important role not only throughout the patient's treatment course, but also in the treatment of unfavorable surgical sequelae.

  9. Treatment of a Maxillary First Molar with Two Palatal Roots

    PubMed Central

    Asghari, Vahideh; Rahimi, Saeed; Ghasemi, Negin; Talebzadeh, Bita; Norlouoni, Ahmad

    2015-01-01

    Thorough knowledge of the morphology and internal anatomy of the root canal system is essential, because it determines the successful outcome of endodontic treatment. The main goal of endodontic treatment is to prevent apical periodontitis and/or to promote the healing of periapical lesion. Presence of two canals or roots on the palatal side of the first maxillary molar has rarely been reported. This case report presents a maxillary first molar with two separate palatal roots. PMID:26523146

  10. A Rat Model for Muscle Regeneration in the Soft Palate

    PubMed Central

    Carvajal Monroy, Paola L.; Grefte, Sander; Kuijpers-Jagtman, Anne M.; Helmich, Maria P. A. C.; Ulrich, Dietmar J. O.; Von den Hoff, Johannes W.; Wagener, Frank A. D. T. G.

    2013-01-01

    Background Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. Despite successful surgical repositioning of the muscles, optimal function is often not achieved. Scar formation and defective regeneration may hamper the functional recovery of the muscles after cleft palate repair. Therefore, the aim of this study is to investigate the anatomy and histology of the soft palate in rats, and to establish an in vivo model for muscle regeneration after surgical injury. Methods Fourteen adult male Sprague Dawley rats were divided into four groups. Groups 1 (n = 4) and 2 (n = 2) were used to investigate the anatomy and histology of the soft palate, respectively. Group 3 (n = 6) was used for surgical wounding of the soft palate, and group 4 (n = 2) was used as unwounded control group. The wounds (1 mm) were evaluated by (immuno)histochemistry (AZAN staining, Pax7, MyoD, MyoG, MyHC, and ASMA) after 7 days. Results The present study shows that the anatomy and histology of the soft palate muscles of the rat is largely comparable with that in humans. All wounds showed clinical evidence of healing after 7 days. AZAN staining demonstrated extensive collagen deposition in the wound area, and initial regeneration of muscle fibers and salivary glands. Proliferating and differentiating satellite cells were identified in the wound area by antibody staining. Conclusions This model is the first, suitable for studying muscle regeneration in the rat soft palate, and allows the development of novel adjuvant strategies to promote muscle regeneration after cleft palate surgery. PMID:23554995

  11. Examination of the depth of the equine hard palate.

    PubMed

    Evans, Rebecca Gay; Lowder, Michael

    2012-01-01

    Equine behavioral problems and loss of optimum performance have been associated with musculoskeletal injury and, more recently, dental disease. Injuries to a horse's tongue and bars of the mandible due to bitting have been documented. However, another point of contact of the bit, the hard palate, has thus far been virtually ignored. The objective of the study was to determine if there was a significant range associated with the depth of the equine hard palate and if this range was associated with a certain breed, age, or sex of the horse. Oral examinations were performed on 52 horses and a measurement of the hard palate was taken. The study group was comprised of 27 mares, 24 geldings and 1 stallion. They were further divided into the age groups: 3-5 years (3), > 5-10 years (18), > 10-15 years (19), and > 15 years (12). Lastly, the groups were divided into the following breed categories: Quarter Horse, Thoroughbred, and Other. Analyses revealed that palate depth has a broad range that is not associated with any breed, age, or sex. Normal reference ranges were established for the data and suggests that the hard palate should be considered and measured when choosing a bit. Further research is necessary to determine which bits are best suited for each palate depth.

  12. Hard palate perforation due to mucormycosis: report of four cases.

    PubMed

    Barrak, H A

    2007-11-01

    Mucormycosis is an opportunistic, fulminating fungal infection of the sino-nasal region. It tends to affect people with immune suppression. The hard palate is a rare site of the disease and few cases have been reported in the literature. This report discusses the nature of hard palate mucormycosis, with the aim of outlining possible explanations and reviewing associated characteristics. This was a prospective analysis of four cases of hard palate mucormycosis. The patients were referred from the medical department, with uncontrolled diabetes mellitus. An aggressive treatment protocol was used, i.e. an intensive course of antifungal drugs and frequent debridement of dead tissue. A painful, dusky red swelling was noticed at the early stages of the hemi-palate lesion. It was eventually followed by deep ulceration and even big perforation. Orbit and intracranial extension was the preceding sign in all instances. The progression of the perforation was not controlled by a full course of treatment. There were two deaths during the treatment course. Mucormycosis of the hard palate is an ominous sign. Although rare, the lesion is progressive in nature and barely controlled by treatment. Clinicians should maintain a high degree of clinical suspicion in the management of patients with palatal ulcer and debilitating illness.

  13. A unified convention for biological assemblies with helical symmetry

    SciTech Connect

    Tsai, Chung-Jung; Nussinov, Ruth

    2011-08-01

    A new representation of helical structure by four parameters, [n{sub 1}, n{sub 2}, twist, rise], is able to generate an entire helical construct from asymmetric units, including cases of helical assembly with a seam. Assemblies with helical symmetry can be conveniently formulated in many distinct ways. Here, a new convention is presented which unifies the two most commonly used helical systems for generating helical assemblies from asymmetric units determined by X-ray fibre diffraction and EM imaging. A helical assembly is viewed as being composed of identical repetitive units in a one- or two-dimensional lattice, named 1-D and 2-D helical systems, respectively. The unification suggests that a new helical description with only four parameters [n{sub 1}, n{sub 2}, twist, rise], which is called the augmented 1-D helical system, can generate the complete set of helical arrangements, including coverage of helical discontinuities (seams). A unified four-parameter characterization implies similar parameters for similar assemblies, can eliminate errors in reproducing structures of helical assemblies and facilitates the generation of polymorphic ensembles from helical atomic models or EM density maps. Further, guidelines are provided for such a unique description that reflects the structural signature of an assembly, as well as rules for manipulating the helical symmetry presentation.

  14. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  15. Helicity in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Kurgansky, Michael; Koprov, Boris; Koprov, Victor; Chkhetiani, Otto

    2017-04-01

    An overview is presented of recent direct field measurements at the Tsimlyansk Scientific Station of A.M. Obukhov Institute of Atmospheric Physics in Moscow of turbulent helicity (and potential vorticity) using four acoustic anemometers positioned, within the atmospheric surface-adjacent boundary layer, in the vertices of a rectangular tetrahedron, with an approximate 5 m distance between the anemometers and a 5.5 m elevation of the tetrahedron base above the ground surface (Koprov, Koprov, Kurgansky and Chkhetiani. Izvestiya, Atmospheric and Oceanic Physics, 2015, Vol.51, 565-575). The same ideology was applied in a later field experiment in Tsimlyansk with the tetrahedron's size of 0.7 m and variable elevation over the ground from 3.5 to 25 m. It is illustrated with examples of the statistical distribution of instantaneous (both positive and negative) turbulent helicity values. A theory is proposed that explains the measured mean turbulent helicity sign, including the sign of contribution to helicity from the horizontal and vertical velocity & vorticity components, respectively, and the sign of helicity buoyant production term. By considering a superposition of the classic Ekman spiral solution and a jet-like wind profile that mimics a shallow breeze circulation over a non-uniformly heated Earth surface, a possible explanation is provided, why the measured mean turbulent helicity sign is negative. The pronounced breeze circulation over the Tsimlyansk polygon which is located nearby the Tsimlyansk Reservoir was, indeed, observed during the measurements period. Whereas, essentially positive helicity is injected into the boundary layer from the free atmosphere in the Northern Hemisphere.

  16. Helical buckling of pipes in extended reach and horizontal wells -- Part 1: Preventing helical buckling

    SciTech Connect

    Wu, J.; Juvkam-Wold, H.C.; Lu, R. . Petroleum Engineering Dept.)

    1993-09-01

    This paper studies the helical buckling of pipes (drillstring and tubing) in extended reach and horizontal wells, theoretically and experimentally, resulting in new equations to correctly predict and effectively prevent the helical buckling of pipes in such wells. The theoretically study shows that the so-called helical buckling load that appears in the current literature is only the average axial load in the helical buckling development process. The laboratory experiments confirm the theoretical analysis. The new helical buckling load equations are formulated by combining the theoretical analysis and the experimental results, thereby resolving the existing assumption-and-result inconsistency in the current literature. The new equation predicts the true helical buckling load to be about 1.3 times the so-called helical buckling load in the current literature, and about 1.8 times the critical buckling load that predicts the onset of sinusoidal buckling. Consequently, larger bit weights or packer setting loads can be applied to increase the drilling rate or to ensure a proper seal, before the helical buckling of the pipes can occur.

  17. The influence of helical background fields on current helicity and electromotive force of magnetoconvection

    NASA Astrophysics Data System (ADS)

    Rüdiger, G.; Küker, M.

    2016-07-01

    Motivated by the empirical finding that the known hemispheric rules for the current helicity at the solar surface are not strict, we demonstrate the excitation of small-scale current helicity by the influence of large-scale helical magnetic background fields on nonrotating magnetoconvection. This is shown within a quasilinear analytic theory of driven turbulence and by nonlinear simulations of magnetoconvection that the resulting small-scale current helicity has the same sign as the large-scale current helicity, while the ratio of both pseudoscalars is of the order of the magnetic Reynolds number of the convection. The same models do not provide finite values of the small-scale kinetic helicity. On the other hand, a turbulence-induced electromotive force is produced including the diamagnetic pumping term, as well as the eddy diffusivity but, however, no α effect. It has thus been argued that the relations for the simultaneous existence of small-scale current helicity and α effect do not hold for the model of nonrotating magnetoconvection under consideration. Calculations for various values of the magnetic Prandtl number demonstrate that, for the considered diffusivities, the current helicity increases for growing magnetic Reynolds number, which is not true for the velocity of the diamagnetic pumping, which is in agreement with the results of the quasilinear analytical approximation.

  18. Ultrasonography in the evaluation of the mid-palatal suture in rapid palatal expansion

    PubMed Central

    Gumussoy, I; Bayrakdar, I S; Dagistan, S; Caglayan, F

    2014-01-01

    Objectives: Orthodontists usually evaluate the mid-palatal sutural opening with occlusal radiography. The purpose of this article is to evaluate the sutural opening with ultrasonography (USG) in a series of patients undergoing rapid palatal expansion (RPE). Methods: The study included 87 USG images and 87 occlusal radiographs from 29 healthy patients (mean age, 13.9 years; range, 11–20 years; boys, 12; girls, 17) who required RPE treatment. The sutural opening was assessed with USG, and the amount of sutural expansion as mesiodistal length was measured immediately after appliance practice (T0), 10 turns (T1) and 20 turns (T2) during the expansion period. Sutural expansion evaluated by occlusal radiographs was scored at every stage. Measurements obtained by USG and scores observed in the occlusal radiographs were compared by non-parametric Kendall's tau test. Results: Both USG and radiographic images revealed normal anatomical structure during pre-expansion (stage T0). On USG, sutural expansion was seen in 19 patients at stage T1. There was no expansion at this stage in ten patients. At stage T2, on USG and radiography, an increase in the amount of expansion was observed in 19 patients with sutural expansion at stage T1 and sutural expansion was observed in 5 patients without sutural expansion at stage T1. No expansion was observed at both stages T1 and T2 in five patients. USG measurements and occlusal scores in both T1 and T2 turns showed statistically significant correlation (p < 0.001). Conclusions: The results indicate that USG might be a useful method to assess mid-palatal sutural opening in patients undergoing RPE. PMID:25168810

  19. A Comparative Study of Oral Microbiota in Infants with Complete Cleft Lip and Palate or Cleft Soft Palate

    PubMed Central

    Tanasiewicz, Marta

    2017-01-01

    Few reports have been published on the early microbiota in infants with various types of cleft palate. We assessed the formation of the oral microbiota in infants with complete cleft lip and palate (CLP n = 30) or cleft soft palate (CSP n = 25) in the neonatal period (T1 time) and again in the gum pad stage (T2 time). Culture swabs from the tongue, palate, and/or cleft margin at T1 and T2 were taken. We analysed the prevalence of the given bacterial species (the percentage) and the proportions in which the palate and tongue were colonised by each microorganism. At T1, Streptococcus mitis (S. mitis) were the most frequently detected in subjects with CLP or CSP (63% and 60%, resp.). A significantly higher frequency of methicillin-sensitive Staphylococcus aureus (S. aureus MSSA) was observed in CLP compared to the CSP group. At T2, significantly higher percentages of S. mitis, S. aureus MSSA, Staphylococcus epidermidis, and members of the Enterobacteriaceae family were noted in CLP infants compared to the CSP. S. mitis and Streptococcus sanguinis appeared with the greatest frequency on the tongue, whereas Streptococcus salivarius was predominant on the palate. The development of the microbiota in CLP subjects was characterised by a significant increase in the prevalence of pathogenic bacteria. PMID:28393073

  20. The anatomy of the dog soft palate. I. Histological evaluation of the caudal soft palate in mesaticephalic breeds.

    PubMed

    Arrighi, Silvana; Pichetto, Michela; Roccabianca, Paola; Romussi, Stefano

    2011-07-01

    The gross anatomy and overall structure of the soft palate has been described in the average dog's head, however, no descriptive microanatomical studies of the dog soft palate are available, despite their possible utility in view of the manifold and important repercussions of this organ physiology. This is the first of two companion papers, dealing with the caudal part of the soft palate in the canine species, in mesaticephalic and brachycephalic dogs. Specimens from mesaticephalic healthy dogs (N = 8) were collected after euthanasia, processed for histology and sectioned at six transversal levels. Morphological stainings were used for a microscopic evaluation of the tissue layers composing the distal part of the soft palate in adult mesaticephalic dogs, and histochemical reactions were applied to assess mucin types within glandular tissue and to investigate the connective tissues. The organ was characteristically organized into a major deep musculo-connective axis mixed with salivary glands and covered by the mucosal lining on either the nasopharyngeal or the oral sides. The results of this investigation add to the general knowledge of the anatomy of soft palate in the canine species and establish baseline information for the parallel study on the long and thickened soft palate, which is typical of adult brachycephalic dogs. Copyright © 2011 Wiley-Liss, Inc.

  1. A Comparative Study of Oral Microbiota in Infants with Complete Cleft Lip and Palate or Cleft Soft Palate.

    PubMed

    Machorowska-Pieniążek, Agnieszka; Mertas, Anna; Skucha-Nowak, Małgorzata; Tanasiewicz, Marta; Morawiec, Tadeusz

    2017-01-01

    Few reports have been published on the early microbiota in infants with various types of cleft palate. We assessed the formation of the oral microbiota in infants with complete cleft lip and palate (CLP n = 30) or cleft soft palate (CSP n = 25) in the neonatal period (T1 time) and again in the gum pad stage (T2 time). Culture swabs from the tongue, palate, and/or cleft margin at T1 and T2 were taken. We analysed the prevalence of the given bacterial species (the percentage) and the proportions in which the palate and tongue were colonised by each microorganism. At T1, Streptococcus mitis (S. mitis) were the most frequently detected in subjects with CLP or CSP (63% and 60%, resp.). A significantly higher frequency of methicillin-sensitive Staphylococcus aureus (S. aureus MSSA) was observed in CLP compared to the CSP group. At T2, significantly higher percentages of S. mitis, S. aureus MSSA, Staphylococcus epidermidis, and members of the Enterobacteriaceae family were noted in CLP infants compared to the CSP. S. mitis and Streptococcus sanguinis appeared with the greatest frequency on the tongue, whereas Streptococcus salivarius was predominant on the palate. The development of the microbiota in CLP subjects was characterised by a significant increase in the prevalence of pathogenic bacteria.

  2. Histopathologic and immunohistochemical features of soft palate muscles and nerves in dogs with an elongated soft palate.

    PubMed

    Arai, Kiyotaka; Kobayashi, Masanori; Harada, Yasuji; Hara, Yasushi; Michishita, Masaki; Ohkusu-Tsukada, Kozo; Takahashi, Kimimasa

    2016-01-01

    To histologically evaluate and compare features of myofibers within the elongated soft palate (ESP) of brachycephalic and mesocephalic dogs with those in the soft palate of healthy dogs and to assess whether denervation or muscular dystrophy is associated with soft palate elongation. Soft palate specimens from 24 dogs with ESPs (obtained during surgical intervention) and from 14 healthy Beagles (control group). All the soft palate specimens underwent histologic examination to assess myofiber atrophy, hypertrophy, hyalinization, and regeneration. The degrees of atrophy and hypertrophy were quantified on the basis of the coefficient of variation and the number of myofibers with hyalinization and regeneration. The specimens also underwent immunohistochemical analysis with anti-neurofilament or anti-dystrophin antibody to confirm the distribution of peripheral nerve branches innervating the palatine myofibers and myofiber dystrophin expression, respectively. Myofiber atrophy, hypertrophy, hyalinization, and regeneration were identified in almost all the ESP specimens. Degrees of atrophy and hypertrophy were significantly greater in the ESP specimens, compared with the control specimens. There were fewer palatine peripheral nerve branches in the ESP specimens than in the control specimens. Almost all the myofibers in the ESP and control specimens were dystrophin positive. These results suggested that palatine myopathy in dogs may be caused, at least in part, by denervation of the palatine muscles and not by Duchenne- or Becker-type muscular dystrophy. These soft palate changes may contribute to upper airway collapse and the progression of brachycephalic airway obstructive syndrome.

  3. Hydrogels of Superlong Helices to Synthesize Hybrid Ag-Helical Nanomaterials.

    PubMed

    Li, Guihua; Wang, Yitong; Wang, Ling; Song, Aixin; Hao, Jingcheng

    2016-11-22

    The gelation behavior of mixtures of sodium deoxycholate (NaDC) and glutathione (GSH) in water is investigated. The system exhibits a structural transition of self-assembled hydrogels from nanofibers to nanohelix structures, and then to helical ribbons with increasing GSH concentration. Superlong helical nanofibers with left- and right-handed orientations are produced by tuning the concentration of GSH at a fixed concentration of NaDC. Random coil and β-sheet structures are significant for the formation of the helical structures, and are indicated by circular dichroism (CD) and Fourier transform infrared (FT-IR) spectra. The mechanical strength of the "weak" hydrogels is enhanced by the introduction of appropriate suitable amount of AgNO3. Furthermore, the controlled growth of Ag nanoparticles at spatially arranged locations along the nanohelices (hybrid Ag-helical nanomaterial) is readily achieved by UV reduction of Ag (I) ions on the supramolecular helical templates.

  4. Progressive ataxia and palatal tremor (PAPT): clinical and MRI assessment with review of palatal tremors.

    PubMed

    Samuel, Michael; Torun, Nurhan; Tuite, Paul J; Sharpe, James A; Lang, Anthony E

    2004-06-01

    Palatal tremor has been subdivided into essential (EPT) and symptomatic palatal tremor (SPT). A subgroup of the SPT form has a syndrome of progressive ataxia and palatal tremor (PAPT). Published details of cases of PAPT are sparse and the disorder appears heterogeneous. We present clinical and MRI features of six patients with sporadic PAPT who attended The University Health Network between 1991 and 2002. Eye movements were recorded using a magnetic search coil technique. We review previously reported cases of PAPT from the English language literature and relate this disorder to EPT and SPT. PAPT may be divided into sporadic and familial forms. We identified 22 other prior reported cases of sporadic PAPT. Sporadic PAPT is a subtype of SPT in which progressive cerebellar degeneration is the most symptomatic feature. A combination of vertical nystagmus and palatal tremor was found in one of our cases. Internuclear ophthalmoplegia, a new finding, was present in two of our patients and indicated additional brainstem dysfunction. Inferior olivary high signal abnormalities were present on MRI in all of our cases. The cause of sporadic PAPT remains uncertain. In some previous reports of sporadic PAPT, the combination of brainstem or pontine atrophy, parkinsonism, autonomic dysfunction or corticospinal tract abnormalities suggests a diagnosis of multiple system atrophy, although pathological verification is lacking. Familial PAPT is associated with marked brainstem and cervical cord atrophy with corticospinal tract findings, but the typical olivary MRI abnormalities have not been reported. A substitution in the glial fibrillary acidic protein (GFAP) gene has been described in a family with PAPT, raising the possibility of Alexander's disease. One other familial syndrome of PAPT, termed 'dark dentate disease', has also been reported. PAPT is a subgroup of SPT in which ataxia progresses and is not usually the result of a monophasic illness. Eye movement abnormalities suggest

  5. Role of neurotransmitters in palate development and teratologic implications.

    PubMed

    Zimmerman, E F

    1985-01-01

    It is hypothesized that neuropharmacologic agents are more teratogenic to humans. Since many neuropharmacologic agents function through neurotransmitter mechanisms, then neurotransmitters should function to regulate embryonic development. Evidence has been obtained that neurotransmitters do indeed function as biological signals in palate development. It has been shown that palate reorientation is modulated by neurotransmitters with a wide range of diversity, similar to the CNS. Thus serotonin and acetylcholine stimulate and GABA inhibits the reorientation process. Spatial diversity is also observed: serotonin functions at the anterior and acetylcholine at the posterior end, and GABA functions more efficiently at either end in different inbred strains. Many criteria for functioning neurotransmitters have been obtained. Both serotonin and GABA have been measured in the palate and developmental changes observed. Physiologic responses to serotonin have been monitored. Serotonin has been shown to stimulate palate cell motility as well as protein carboxyl methylation and cyclic GMP. The serotonin effects on protein carboxyl methylation and cyclic GMP could function to stimulate palate reorientation by modulating cell contractility and protein secretion. Further support for the hypothesis that neuropharmacologic agents could be teratogenic by perturbation of neurotransmitter mechanisms comes from studying GABA and diazepam. Evidence has been obtained that diazepam induces cleft palate by mimicking GABA in a functional GABAergic system in palate development. A significant finding is that genetic differences in both diazepam teratogenesis and in a GABAergic system have been observed. Comparing the SWV and AJ strains, the SWV mouse showed (1) a greater sensitivity to diazepam-induced cleft palate, (2) a greater sensitivity to GABA and diazepam inhibition of palate reorientation in embryo culture, (3) a greater concentration of palatal GABA and (4) a more efficient GABA

  6. DNS of helicity-induced stratified turbulent flow

    NASA Astrophysics Data System (ADS)

    Chandy, Abhilash J.; Rahimi, Abbas

    2013-11-01

    Helical flows undergoing density stratification have wide applications in meteorological phenomena such as dust devils, tornadoes, and hurricanes due to the complexity and disasters caused by them. Direct numerical simulations (DNS) of transition to turbulence in a stably stratified Boussinesq fluid are presented for different rotation and stratification intensities. In order to understand the effect of velocity on the energy cascade, comparisons are made between helicity initiated and non-helical flows. Results show that stratification decelerates the helicity decay and causes velocity and vorticity to align with each other. With respect to the helical and non-helical flow comparisons, the total energy in the presence of stratification decays faster with helicity. In addition, the behavior of length scales were examined by comparing temporal variations of the vertical shearing of velocities. Results showed a growing asymmetry with time in the case of helical flow, while non-helical flow stayed close to begin symmetric.

  7. Evaluation of helicity generation in the tropical storm Gonu

    NASA Astrophysics Data System (ADS)

    Farahani, Majid M.; Khansalari, Sakineh; Azadi, Majid

    2017-06-01

    Helicity is a valuable dynamical concept for the study of rotating flows. Consequently helicity flux, indicative of the source or sink of helicity, owns comparable importance. In this study, while reviewing the existing methods, a mathematical relation between helicity and helicity-flux is introduced, discussed and examined. The computed values of helicity and helicity fluxes in an actual case, using the classical and this proposed method are compared. The down-stream helicity flux including sources and sinks of helicity is considered for the tropical storm Gonu that occurred over the coasts of Oman and Iran on June 2-7, 2007. Results show that the buoyancy, through the upper troposphere down to a height within boundary layer, is the main source in producing helicity, and surface friction from earth surface up to a height within boundary layer, is the main dissipating element of helicity. The dominance of buoyancy forcing over the dissipative friction forcing results in generation of vortex or enhancement of it after bouncing the land. Furthermore, the increase (decrease) of helicity results in an increase (decrease) in the height of the level in which maximum helicity flux occurs. It is suggested that the maximum helicity flux occurs at the top of the turbulent boundary layer, so that the height of boundary layer could be obtained.

  8. Fabrication and experimentation of FRP helical spring

    NASA Astrophysics Data System (ADS)

    Ekanthappa, J.; Shiva Shankar, G. S.; Amith, B. M.; Gagan, M.

    2016-09-01

    In present scenario, the automobile industry sector is showing increased interest in reducing the unsprung weight of the automobile & hence increasing the fuel Efficiency. One of the feasible sub systems of a vehicle where weight reduction may be attempted is vehicle- suspension system. Usage of composite material is a proven way to lower the component weight without any compromise in strength. The composite materials are having high specific strength, more elastic strain energy storage capacity in comparison with those of steel. Therefore, helical coil spring made of steel is replaceable by composite cylindrical helical coil spring. This research aims at preparing a re-usable mandrel (mould) of Mild steel, developing a setup for fabrication, fabrication of FRP helical spring using continuous glass fibers and Epoxy Resin (Polymer). Experimentation has been conducted on fabricated FRP helical spring to determine its strength parameters & for failure analysis. It is found that spring stiffness (K) of Glass/Epoxy helical-spring is greater than steel-coil spring with reduced weight.

  9. TURBULENT DYNAMOS WITH SHEAR AND FRACTIONAL HELICITY

    SciTech Connect

    Kaepylae, Petri J.; Brandenburg, Axel

    2009-07-10

    Dynamo action owing to helically forced turbulence and large-scale shear is studied using direct numerical simulations. The resulting magnetic field displays propagating wave-like behavior. This behavior can be modeled in terms of an {alpha}{omega} dynamo. In most cases super-equipartition fields are generated. By varying the fraction of helicity of the turbulence the regeneration of poloidal fields via the helicity effect (corresponding to the {alpha}-effect) is regulated. The saturation level of the magnetic field in the numerical models is consistent with a linear dependence on the ratio of the fractional helicities of the small and large-scale fields, as predicted by a simple nonlinear mean-field model. As the magnetic Reynolds number (Re{sub M}) based on the wavenumber of the energy-carrying eddies is increased from 1 to 180, the cycle frequency of the large-scale field is found to decrease by a factor of about 6 in cases where the turbulence is fully helical. This is interpreted in terms of the turbulent magnetic diffusivity, which is found to be only weakly dependent on the Re{sub M}.

  10. Aerodynamic studies of cleft-palate speech.

    PubMed

    Dickson, S; Barron, S; McGlone, R E

    1978-05-01

    The aerodynamic oral-nasal factors related to the speech of two groups of cleft-palate children were evaluated. One group presented hypernasality and the other group presented normal nasal resonance. The aerodynamic parameters evaluated were oral pressure, nasal flow, and flow-pressure ratio (nasal flow/oral pressure). Oral temperature readings were also obtained. These parameters were evaluated under three conditions (1) blowing, (2) vocalizing the vowel /i/, and (3) reading eight sentences representing two different rhythm patterns, two types of consonant loadings, and two conditions of syllable stress. The findings revealed significant differences between the hypernasal and normal resonance groups in flow-pressure ratio, oral pressure, and nasal flow while subjects were reading sentences. However, only a small proportion of the variability in these aerodynamic measurements could be accounted for based on the classification of hypernasality or normal nasal resonance. Oral-nasal aerodynamic studies done during speaking activity are more useful clinically than blowing activity or saying vowel sounds. No aerodynamic differences were noted between the two groups for the different rhythm and stress patterns and phonemic loadings within the sentences used.

  11. PREVALENCE OF CLEFT LIP AND PALATE IN GEORGIA.

    PubMed

    Chincharadze, S; Vadachkoria, Z; Mchedlishvili, I

    2017-01-01

    Cleft lip and palate take significant place in congenital malformations. We aimed to study epidemiological peculiarities of these pathologies in Georgia for 2006-2015. We compared magnitude of its distribution with the data from 1981-1990. Prevalence of cleft lip and palate in Georgia in 2006-2015 was 0.95±0.04 per 1000 live births, while in 1981-1990- it was 1.05, i.e. in contrast to 1980's frequency of these pathological conditions decreased to some extent. Distribution of cleft lip and palate varies across the country regions. The most intensive spread has been observed in Mtskheta-Mtianeti region, where prevalence composed 2.28/1000. In the rest of the regions frequency of these pathologies is significantly lower. For instance, in Kakheti the rate is equal to 1,87/1000, in Kvemo Kartli - 1.56/1000, in Shida Kartli - 1.55/1000. In the rest of the regions prevalence rate is lower than the country average. It should be noted that in Tbilisi the rate is as low as 0.80/1000. The lowest level has been reported in Guria - 0.56/1000. Currently cleft lip with palate is the most frequently occurring anomaly in Georgia accounting for 39.8% of all congenital malformations. Cleft lip alone ranks the second - 36.1%, followed by cleft palate (24.1%). These pathologies are more frequent in boys than in girls. 60.3% of the cases are reported in males, in contrast to girls - 39.7% (p<0.01). Usually, cleft palate is the most common among girls, but in our case, it had higher prevalence among boys, 53.6% vs. 46,4%. Thus cleft lip and palate distribution in Georgia is characterized by epidemiological peculiarities, which should be considered in implementation of preventive measures.

  12. Effects of dexamethasone on palate mesenchymal cell phospholipase activity

    SciTech Connect

    Bulleit, R.F.; Zimmerman, E.F.

    1984-09-15

    Corticosteroids will induce cleft palate in mice. One suggested mechanism for this effect is through inhibition of phospholipase activity. This hypothesis was tested by measuring the effects of dexamethasone, a synthetic corticosteroid, on phospholipase activity in cultures of palate mesenchymal cells. Palate mesenchymal cells were prelabeled with (3H)arachidonic acid. The cells were subsequently treated with various concentrations of dexamethasone. Concurrently, cultures of M-MSV-transformed 3T3 cells were prepared identically. After treatment, phospholipase activity was stimulated by the addition of serum or epidermal growth factor (EGF), and radioactivity released into the medium was taken as a measure of phospholipase activity. Dexamethasone (1 X 10(-5) or 1 X 10(-4) M) could inhibit serum-stimulated phospholipase activity in transformed 3T3 cells after 1 to 24 hr of treatment. However, no inhibition of activity was measured in palate mesenchymal cells following this period of treatment. Not until 120 hr of treatment with dexamethasone (1 X 10(-4) M) was any significant inhibition of serum-stimulated phospholipase activity observed in palate mesenchymal cells. When EGF was used to stimulate phospholipase activity, dexamethasone (1 X 10(-5) M) caused an increase in phospholipase activity in palate mesenchymal cells. These observations suggested that phospholipase in transformed 3T3 cells was sensitive to inhibition by dexamethasone. However, palate mesenchymal cell phospholipase is only minimally sensitive to dexamethasone, and in certain instances can be enhanced. These results cannot support the hypothesis that corticosteroids mediate their teratogenic effect via inhibition of phospholipase activity.

  13. Association of achondroplasia with Down syndrome: difficulty in prenatal diagnosis by sonographic and 3-D helical computed tomographic analyses.

    PubMed

    Kaga, Akimune; Murotsuki, Jun; Kamimura, Miki; Kimura, Masato; Saito-Hakoda, Akiko; Kanno, Junko; Hoshi, Kazuhiko; Kure, Shigeo; Fujiwara, Ikuma

    2015-05-01

    Achondroplasia and Down syndrome are relatively common conditions individually. But co-occurrence of both conditions in the same patient is rare and there have been no reports of fetal analysis of this condition by prenatal sonographic and three-dimensional (3-D) helical computed tomography (CT). Prenatal sonographic findings seen in persons with Down syndrome, such as a thickened nuchal fold, cardiac defects, and echogenic bowel were not found in the patient. A prenatal 3-D helical CT revealed a large head with frontal bossing, metaphyseal flaring of the long bones, and small iliac wings, which suggested achondroplasia. In a case with combination of achondroplasia and Down syndrome, it may be difficult to diagnose the co-occurrence prenatally without typical markers of Down syndrome.

  14. Helical X-ray phase-contrast computed tomography without phase stepping

    NASA Astrophysics Data System (ADS)

    Marschner, M.; Willner, M.; Potdevin, G.; Fehringer, A.; Noël, P. B.; Pfeiffer, F.; Herzen, J.

    2016-04-01

    X-ray phase-contrast computed tomography (PCCT) using grating interferometry provides enhanced soft-tissue contrast. The possibility to use standard polychromatic laboratory sources enables an implementation into a clinical setting. Thus, PCCT has gained significant attention in recent years. However, phase-contrast CT scans still require significantly increased measurement times in comparison to conventional attenuation-based CT imaging. This is mainly due to a time-consuming stepping of a grating, which is necessary for an accurate retrieval of the phase information. In this paper, we demonstrate a novel scan technique, which directly allows the determination of the phase signal without a phase-stepping procedure. The presented work is based on moiré fringe scanning, which allows fast data acquisition in radiographic applications such as mammography or in-line product analysis. Here, we demonstrate its extension to tomography enabling a continuous helical sample rotation as routinely performed in clinical CT systems. Compared to standard phase-stepping techniques, the proposed helical fringe-scanning procedure enables faster measurements, an extended field of view and relaxes the stability requirements of the system, since the gratings remain stationary. Finally, our approach exceeds previously introduced methods by not relying on spatial interpolation to acquire the phase-contrast signal.

  15. Working member of a helical downhole motor for drilling wells

    SciTech Connect

    Kochnev, A.M.; Vshivkov, A.N.; Goldobin, V.B.

    1993-06-22

    A working member of a helical downhole motor is described for drilling wells comprising: separate tubular sections having helical teeth arranged in succession and interconnected by connecting elements, each connecting element having the form of a ring, rigidly secured at the tubular sections and having helical teeth of a pitch and a direction equal to a pitch and a direction, respectively, of the helical teeth of the tubular sections, whereas a profile of the helical teeth of the ring is equidistant to a profile of the helical teeth of the sections.

  16. Oxytocin gene deletion mice overconsume palatable sucrose solution but not palatable lipid emulsions.

    PubMed

    Miedlar, J A; Rinaman, L; Vollmer, R R; Amico, J A

    2007-09-01

    We previously reported that oxytocin knockout (OT KO) mice display markedly enhanced intake of sweet and nonsweet carbohydrate solutions compared with intake by wild-type (WT) mice of the same background strain. The present study was conducted to determine whether OT KO mice demonstrate enhanced intake of Intralipid, a palatable lipid emulsion. Male or female mice of both genotypes that were naive to the test solution were given continuous two-bottle access to Intralipid and water with food available ad libitum for 3 days. Throughout the experiment, mice of both genotypes showed a marked preference for Intralipid over water. On the 1st day, OT KO mice displayed twofold greater preference and consumed nearly twice as much Intralipid compared with WT cohorts. However, on subsequent days of exposure, Intralipid preference and intake did not differ between genotypes over a range of lipid concentrations presented in descending or ascending order. Daily and hourly measures of lipid vs. sucrose intake confirmed that OT KO mice consumed more sucrose solution, but not lipid emulsion, than WT mice. During ad libitum access to Intralipid, both genotypes consumed significantly more calories from the emulsion as concentration increased. Both genotypes maintained consistent total daily caloric intake (lipid plus chow) and compensated by decreasing chow intake over the course of the study. These findings, coupled with prior reports from our laboratory, support the view that OT signaling pathways participate in limiting intake of palatable carbohydrate-containing solutions, but do not appear to play a role in limiting intake of Intralipid.

  17. A helically distorted MHD flux rope model

    NASA Technical Reports Server (NTRS)

    Theobald, Michael L.; Montgomery, David

    1990-01-01

    A flux rope model is proposed which has a variable degree of helical distortion from axisymmetry. The basis for this suggestion is a series of numerical and analytical investigations of magnetohydrodynamic states which result when an axial electric current is directed down on dc magnetic field. The helically distorted states involve a flow velocity and seem to be favored because of their lower rate of energy dissipation. Emphasis is on the magnetometer and particle energy analyzer traces that might be characteristic of such flux ropes. It is shown that even a fractionally small helical distortion may considerably alter the traces in minimum-variance coordinates. In short, what may be fairly common MHD processes can render a flux rope almost unrecognizable under standard diagnostics, even if the departures from axisymmetry are not great.

  18. Structural Transition from Helices to Hemihelices

    PubMed Central

    Su, Tianxiang; Bertoldi, Katia; Clarke, David R.

    2014-01-01

    Helices are amongst the most common structures in nature and in some cases, such as tethered plant tendrils, a more complex but related shape, the hemihelix forms. In its simplest form it consists of two helices of opposite chirality joined by a perversion. A recent, simple experiment using elastomer strips reveals that hemihelices with multiple reversals of chirality can also occur, a richness not anticipated by existing analyses. Here, we show through analysis and experiments that the transition from a helical to a hemihelical shape, as well as the number of perversions, depends on the height to width ratio of the strip's cross-section. Our findings provides the basis for the deterministic manufacture of a variety of complex three-dimensional shapes from flat strips. PMID:24759785

  19. Generation of acoustic helical wavefronts using metasurfaces

    NASA Astrophysics Data System (ADS)

    Esfahlani, Hussein; Lissek, Herve; Mosig, Juan R.

    2017-01-01

    It has been shown that acoustic waves with helical wavefronts can carry angular momentum, which can be transmitted towards a propagating medium. Such a wave field can be achieved by using a planar array of electroacoustic transducers, forming a given spatial distribution of phased sound sources which produce the desired helical wavefronts. Here, we introduce a technique to generate acoustic vortices, based on the passive acoustic metasurface concept. The proposed metasurface is composed of space-coiled cylindrical unit cells transmitting sound pressure with a controllable phase shift, which are arranged in a discretized circular configuration, and thus passively transforming an incident plane wavefront into the desired helical wavefront. This method presents the advantage of overcoming the restrictions on using many acoustic sources, and it is implemented with a transmitting metasurface which can be easily three-dimensionally printed. The proposed straightforward design principle can be adopted for easy production of acoustic angular momentum with minimum complexity and using a single source.

  20. Unusually Stable Helical Coil Allotrope of Phosphorus.

    PubMed

    Liu, Dan; Guan, Jie; Jiang, Jingwei; Tománek, David

    2016-12-14

    We have identified an unusually stable helical coil allotrope of phosphorus. Our ab initio density functional theory calculations indicate that the uncoiled, isolated straight one-dimensional chain is equally stable as a monolayer of black phosphorus dubbed phosphorene. The coiling tendency and the attraction between adjacent coil segments add an extra stabilization energy of ∼12 meV/atom to the coil allotrope, similar in value to the ∼16 meV/atom interlayer attraction in bulk black phosphorus. Thus, the helical coil structure is essentially as stable as black phosphorus, the most stable phosphorus allotrope known to date. With an optimum radius of 2.4 nm, the helical coil of phosphorus may fit well and even form inside wide carbon nanotubes.