Evaluation of MR cisternography of the cerebellopontine angle using a balanced fast-field-echo sequence: preliminary findings

Energy Technology Data Exchange (ETDEWEB)

Tsuchiya, Kazuhiro; Aoki, Chinatsu; Hachiya, Junichi [Department of Radiology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, 181-8611, Tokyo (Japan)

2004-02-01

We evaluated the feasibility of MR cisternography by the balanced fast-field-echo (bFFE) sequence, comparing with that by a turbo-spin-echo (TSE) sequence, for cerebellopontine angle lesions on a 1.5-T imager (Gyroscan Intera, Philips, Best, The Netherlands). The bFFE MR cisternograms depicted target cranial nerves with less cerebrospinal fluid pulsation artifacts than TSE cisternograms and visualized an acoustic schwannoma in 6 of 44 patients with suspicion and a causative vessel of hemifacial spasm in all of 3 patients in a short scanning time (1 min 53 s). The bFFE sequence can be promising for MR cisternography in the diagnosis of cerebellopontine angle lesions. (orig.)

[Endoscopic assistance in surgery of cerebellopontine angle tumors].

Science.gov (United States)

Poshataev, V K; Shimansky, V N; Tanyashin, S V; Karnaukhov, V V

2014-01-01

During the period of 2010-2012, 33 patients with cerebellopontine angle tumors were operated on at the Burdenko Neurosurgical Institute (Moscow, Russia) using different types of endoscopic assistance. All patients were operated on via the retrosigmoid suboccipital approach in semi-sitting and prone positions. 30° and 70° endoscopes were used during the surgery. Endoscopic assistance allowed us to increase the completeness of tumor removal and to reduce the risk of postoperative complications by retaining the anatomic integrity of cranial nerves and vascular structures in the base of the posterior cranial fossa. These benefits made it possible to maintain and improve quality of life in patients with CPA tumors in the postoperative period.

A rare case of malignant triton tumor in the cerebellopontine angle

Directory of Open Access Journals (Sweden)

Gong Li

2012-04-01

Full Text Available Abstract Malignant triton tumor (MTT is defined as malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation. Intracranial MTT is extremely rare, and only four cases have been reported in the literature. Here, we report a case of MTT occurring in the cerebellopontine angle, and describe its histopathological characteristics, immunohistochemical features, and prognosis. Virtual slides The virtual slide(s for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1336227313684480

Glioneuronal Heterotopia Presenting As a Cerebellopontine angle Tumor of the cranial Nerve VIII, Case Report.

Science.gov (United States)

Peris-Celda, M; Giannini, C; Diehn, F E; Eckel, L J; Neff, B A; Van Gompel, J J

2018-04-03

Vestibular schwannomas and meningiomas account for the great majority of lesions arising in the cerebellopontine angle (CPA). In this report, we present a case of glioneuronal heterotopia, also known as glioneuronal hamartoma, arising from the VIII cranial nerve, which is an extremely uncommon lesion. Important radiologic and surgical aspects are reviewed, which may help in early recognition and intraoperative decision making when these lesions are encountered. A healthy 29-year-old female presented with intermittent right facial numbness. Magnetic resonance imaging (MRI) showed an incidental minimally enhancing cerebellopontine angle lesion on the right VII-VIII cranial nerve complex. The patient declined serial observation and opted for operative intervention for resection. Intraoperatively, the lesion resembled neural tissue and was continuous with the VIII cranial nerve. Pathological analysis demonstrated mature glioneuronal tissue consistent with hamartomatous brain tissue. The patient maintained normal hearing and facial nerve function after surgery. Radiologic, surgical and pathological characteristics are described. Ectopic glioneuronal tissue of the VIII cranial nerve is a rare non-neoplastic lesion, and should be considered in the differential diagnosis of unusual appearing intracanalicular and cerebellopontine angle lesions. The congenital and benign nature of this entity makes observation a valid option for these cases, although they are so infrequent that they are often presumptively managed as vestibular schwannomas. Attempts to radically resect these lesions may result in higher rates of hearing loss or facial palsy due to their continuity with the cranial nerves. Copyright © 2018 Elsevier Inc. All rights reserved.

Contrast-enhanced CISS imaging of cerebellopontine angle tumors

Energy Technology Data Exchange (ETDEWEB)

Tozaki, Mitsuhiro; Toyoda, Keiko; Hata, Yuichi; Fukuda, Yasushi; Fukuda, Kunihiko [Jikei Univ., Tokyo (Japan). School of Medicine; Katano, Shuichi

1999-10-01

Our purpose of this study was to evaluate the clinical usefulness of contrast-enhanced CISS-3DFT MR imaging for the diagnosis of CP angle tumors. CISS-3DFT MR imaging is expected for screening procedure of acoustic schwannoma because of excellent spatial resolution. Recently, we discovered contrast enhancement effect on CISS sequence in spite of heavily T{sub 2}-weighted images. Fourteen patients with CP angle tumors were performed on a 1.0 T MR unit. Transaxial CISS-3DFT MRI was obtained both before and after intravenous injections of Gd-DTPA. Multiplanar reconstructions (MPRs) were performed in all cases. Contrast enhancement effect of CP angle tumors, and the relationship between tumors and the adjacent cranial nerves were evaluated. Contrast enhancement effect of the tumors was present in all cases in spite of heavily T{sub 2}-weighted images of CISS sequences. In the internal auditory canal, relationship between the tumors and the cranial nerves was demonstrated in 6 cases (6/9). In the cerebellopontine cistern, all cases were demonstrated (11/11). Contrast-enhanced CISS-3DFT MR imaging with a good contrast resolution and an excellent spatial resolution is useful for the diagnosis of CP angle tumors. (author)

Cellular solitary fibrous tumor (hemangiopericytoma) with anaplasia at cerebellopontine angle--a case report.

Science.gov (United States)

Zeng, Jianying; Ogera, Patricia; Benardete, Ethan A; Nicastri, Anthony D; Rao, Chandrakant

2012-08-15

Cellular solitary fibrous tumor is currently considered a synonym for hemangiopericytoma, as it became increasingly clear that the morphological and immunohistochemical features that separate these two entities have become tenuous, and evidence for a unifying concept has emerged. Furthermore, as no evidence of pericytic differentiation is given in most cases of hemangiopericytoma, this diagnostic term is waning in popularity. We present here a case of cellular solitary fibrous tumor in a 22-year-old man. Neuroimaging revealed a right cerebellopontine angle tumor. Most of the tumor was cellular although some less cellular areas were seen. Sinusoidally dilated large vessels, including staghorn type, were seen. Nuclear pleomorphism and increased mitotic activity (5 mitosis/10 high power field) were regarded as evidence of anaplasia. Diffuse CD34 immunoreactivity and focal positivity for Factor XIIIa were seen in the tumor, which was negative for EMA and S100. The tumor also displayed rich reticulin network. Solitary fibrous tumor at cerebellopontine angle is rare, and 20 such cases (five reported as hemangiopericytoma) have been reported in the English literature. Copyright © 2012 Elsevier GmbH. All rights reserved.

Inflammatory lesions of the brainstem and the cerebellopontine angle; Entzuendungen des Hirnstamms und des Kleinhirnbrueckenwinkels

Energy Technology Data Exchange (ETDEWEB)

Lutz, J.; Jaeger, L. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen (Germany). Institut fuer Klinische Radiologie

2006-03-15

Inflammatory lesions of the brainstem and the cerebellopontine angle are often critical for the patient, because crucial neuronal and vascular structures are found in this region. The patient's prognosis mainly depends on rapid identification of the inflammation site and the radiological evaluation of the inflammation pathogenesis to develop therapeutic strategies. Therefore, cross-sectional imaging is complementary to laboratory and CSF analysis as well as biopsies. This article gives a survey of inflammatory lesions of the brainstem and the cerebellopontine angle. (orig.) [German] Entzuendliche Erkrankungen des Hirnstamms und Kleinhirnbrueckenwinkels stellen nicht selten eine kritische Situation fuer den Patienten dar, da in diesen Regionen wichtige neuronale Strukturen und Gefaesse verlaufen. Die Prognose und das weitere therapeutische Vorgehen haengen entscheidend von einer schnellen Diagnose der Entzuendungslokalisation sowie einer bildmorphologischen Einordnung der Entzuendungspathogenese ab. Folglich ergaenzt die Schnittbildgebung entscheidend die Liquoranalyse, die Biopsie und die Laboruntersuchungen. In diesem Artikel soll eine Uebersicht ueber die verschiedenen entzuendlichen Veraenderungen des Hirnstamms und Kleinhirnbrueckenwinkels gegeben werden. (orig.)

Nonvestibular schwannoma tumors in the cerebellopontine angle: A structured approach and management guidelines

DEFF Research Database (Denmark)

Springborg, J.B.; Poulsgaard, L.; Thomsen, Jens Christian

2008-01-01

The most common cerebellopontine angle (CPA) tumor is a vestibular schwannoma, but one in five CPA tumors are not vestibular schwannomas. These tumors may require different management strategies. Compared with vestibular schwannomas, symptoms and signs from cranial nerve VIII are less frequent......: other cranial nerve and cerebellar symptoms and signs predominate in patients with these less common CPA tumors. Computed tomography and magnetic resonance imaging often show features leading to the correct diagnosis. Treatment most often includes surgery, but a policy of observation or subtotal...

Vascular anomalies of the cerebellopontine angle; Vaskulaere Erkrankungen des Kleinhirnbrueckenwinkels

Energy Technology Data Exchange (ETDEWEB)

Papanagiotou, P.; Grunwald, I.Q.; Politi, M.; Struffert, T.; Ahlhelm, F.; Reith, W. [Universitaetsklinikum des Saarlandes, Homburg/Saar (Germany). Klinik fuer Diagnostische und Interventionelle Neuroradiologie

2006-03-15

Vascular anomalies of the cerebellopontine angle are rare compared to tumors in this area. Irritation of the trigeminal, facial, or vestibulocochlear nerve may cause trigeminal neuralgia, hemifacial spasm and vertigo, or tinnitus accordingly. Vessel loops in the cerebellopontine cisterns may cause compression at the root entry or exit zone of the cranial nerves V, VII, and VIII, a phenomenon which is called ''vascular loop syndrome.'' Megadolichobasilar artery and aneurysms of the vertebrobasilar system can also lead to dislocation and compression of the cranial nerves and brain stem. Three-dimensional CISS MR imaging and MR angiography are useful in the detection of neurovascular compression. Microvascular decompression is an effective surgical procedure in the management of compression syndromes of the cranial nerves V, VII, and VIII. (orig.) [German] Gegenueber den Raumforderungen stellen vaskulaere Veraenderungen des Kleinhirnbrueckenwinkels eher eine Ausnahme dar. Trigeminusneuralgie, hemifazialer Spasmus und Schwindel oder Tinnitus koennen bei Irritationen des Nervus trigeminus, facialis und vestibulocochlearis auftreten. Schlingenbildungen der Gefaesse in den Kleinhirnzisternen koennen eine Kompression der Eintritts- oder Austrittszonen der Hirnnerven V, VII und VIII am Hirnstamm hervorrufen, was als ''Vascular-loop-Syndrom'' bezeichnet wird. Zu Verlagerungen und Kompressionen von Hirnnerven und Hirnstamm koennen, wenn auch seltener, die Megadolichobasilaris und Aneurysmen des vertebrobasilaeren Systems fuehren. Bezueglich der Bildgebung ist die Magnetresonanztomographie (MRT) die Methode der Wahl. Die 3D-CISS-Sequenz und die MR-Angiographie sind hilfreich zur Darstellung der neurovaskulaeren Kompression. Die Methode der mikrovaskulaeren Dekompression ist eine wirkungsvolle Methode zur Beseitigung gefaessbedingter Kompressionen der Hirnnerven V, VII und VIII. (orig.)

Vascular anomalies of the cerebellopontine angle; Vaskulaere Erkrankungen des Kleinhirnbrueckenwinkels

Energy Technology Data Exchange (ETDEWEB)

Papanagiotou, P; Grunwald, I Q; Politi, M; Struffert, T; Ahlhelm, F; Reith, W [Universitaetsklinikum des Saarlandes, Homburg/Saar (Germany). Klinik fuer Diagnostische und Interventionelle Neuroradiologie

2006-03-15

Vascular anomalies of the cerebellopontine angle are rare compared to tumors in this area. Irritation of the trigeminal, facial, or vestibulocochlear nerve may cause trigeminal neuralgia, hemifacial spasm and vertigo, or tinnitus accordingly. Vessel loops in the cerebellopontine cisterns may cause compression at the root entry or exit zone of the cranial nerves V, VII, and VIII, a phenomenon which is called ''vascular loop syndrome.'' Megadolichobasilar artery and aneurysms of the vertebrobasilar system can also lead to dislocation and compression of the cranial nerves and brain stem. Three-dimensional CISS MR imaging and MR angiography are useful in the detection of neurovascular compression. Microvascular decompression is an effective surgical procedure in the management of compression syndromes of the cranial nerves V, VII, and VIII. (orig.) [German] Gegenueber den Raumforderungen stellen vaskulaere Veraenderungen des Kleinhirnbrueckenwinkels eher eine Ausnahme dar. Trigeminusneuralgie, hemifazialer Spasmus und Schwindel oder Tinnitus koennen bei Irritationen des Nervus trigeminus, facialis und vestibulocochlearis auftreten. Schlingenbildungen der Gefaesse in den Kleinhirnzisternen koennen eine Kompression der Eintritts- oder Austrittszonen der Hirnnerven V, VII und VIII am Hirnstamm hervorrufen, was als ''Vascular-loop-Syndrom'' bezeichnet wird. Zu Verlagerungen und Kompressionen von Hirnnerven und Hirnstamm koennen, wenn auch seltener, die Megadolichobasilaris und Aneurysmen des vertebrobasilaeren Systems fuehren. Bezueglich der Bildgebung ist die Magnetresonanztomographie (MRT) die Methode der Wahl. Die 3D-CISS-Sequenz und die MR-Angiographie sind hilfreich zur Darstellung der neurovaskulaeren Kompression. Die Methode der mikrovaskulaeren Dekompression ist eine wirkungsvolle Methode zur Beseitigung gefaessbedingter Kompressionen der Hirnnerven V, VII und VIII. (orig.)

Lipoma do ângulo pontocerebelar: relato de caso Lipoma of the cerebellopontine angle: case report

Directory of Open Access Journals (Sweden)

WALTER JOSÉ FAGUNDES-PEREYRA

2000-09-01

Full Text Available Os lipomas do ângulo pontocerebelar são tumores muito raros. Em geral são assintomáticos, achados fortuitos em autópsia, tomografia computadorizada (TC de crânio ou ressonância nuclear magnética do encéfalo. Os autores apresentam o caso de paciente, feminina, branca, 14 anos, há três anos com diminuição da audição à esquerda e há um ano com cefaléia, tipo hemicrânia à esquerda. A TC de crânio evidenciou lesão hipodensa, sem captação de contraste, no ângulo pontocerebelar esquerdo. A paciente foi submetida a cirurgia por via retrossigmóidea para abordagem da lesão, que se apresentou de coloração amarelada, característica de tecido adiposo. Tendo em vista o envolvimento de estruturas nervosas (VII e VIII nervos cranianos, optou-se pela exérese parcial da lesão. A paciente evoluiu com melhora da cefaléia, sem piora do déficit auditivo. Após três anos de seguimento, mantém o quadro estável. Conclui-se que os lipomas do ângulo pontocerebelar, quando assintomáticos, podem ser tratados conservadoramente. Entretanto aqueles associados a sintomatologia persistente e progressiva devem ser operados. A exérese total ou parcial vai depender do envolvimento ou não das estruturas neurovasculares adjacentes.Lipoma of the cerebellopontine angle is a very rare tumor. We report the case of a 14-years-old female, with left side deafness during three years, associated with headache. CT scan showed an hypodense mass, without enhancement at the cerebellopontine angle. The patient was treated surgically by left retrosigmoid approach. The lesion involved the eighth and seventh cranial nerves and only a partial removal was performed. The postoperative course was uneventful. She had no more headache; the deafness of the left side remained unchanged. Asymptomatic lipoma of the cerebellopontine angle can be treated conservatively, although those with progressive symptoms should be treated surgically, with total or partial remove

Cerebellopontine angle lipomas: magnetic resonance imaging findings in two cases

Energy Technology Data Exchange (ETDEWEB)

Borges, Rafael S. [Clinica de Diagnostico por Imagem Multi-Imagem, Rio de Janeiro, RJ (Brazil); Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Radiologia; Brito, Cecilia Castelo Branco [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Fac. de Medicina; Carvalho, Gustavo A. [Clinica Bambina, Rio de Janeiro, RJ (Brazil). Dept. de Neurocirurgia; Hospital Silvestre, Rio de Janeiro, RJ (Brazil); Domingues, Romeu C. [Clinicas CDPI e Multi-Imagem, Rio de Janeiro RJ (Brazil); Gasparetto, Emerson L. [Clinicas CDPI e Multi-Imagem, Rio de Janeiro RJ (Brazil)

2009-07-01

Vestibular schwannomas and meningiomas are the most common lesions of the cerebellopontine angle (CPA), accounting for approximately 85-90% of the tumors seen in this location. Lipomas are rare at this topography, representing about 0.15% of the CPA lesions. These tumors are mal developmental masses that arise from abnormal differentiation of the meninx primitive. Clinically, CPA lipomas can cause slowly progressive neurological symptoms and signs affecting cranial nerves or brain stem. Because these lesions usually are strongly attached to the surrounding structures, any surgical attempts of complete resection can result in neural or vascular damage, reinforcing the importance of the pre-operative imaging diagnosis. Although the CT findings of CPA lipomas can be typical, the magnetic resonance (MR) imaging, especially the fat suppression sequences, had improved the identification of these lesions. We aimed to report two patients with a CPA lipoma, emphasizing the MR imaging findings. (author)

Cerebellopontine angle lipomas: magnetic resonance imaging findings in two cases

International Nuclear Information System (INIS)

Borges, Rafael S.; Domingues, Romeu C.; Gasparetto, Emerson L.

2009-01-01

Vestibular schwannomas and meningiomas are the most common lesions of the cerebellopontine angle (CPA), accounting for approximately 85-90% of the tumors seen in this location. Lipomas are rare at this topography, representing about 0.15% of the CPA lesions. These tumors are mal developmental masses that arise from abnormal differentiation of the meninx primitive. Clinically, CPA lipomas can cause slowly progressive neurological symptoms and signs affecting cranial nerves or brain stem. Because these lesions usually are strongly attached to the surrounding structures, any surgical attempts of complete resection can result in neural or vascular damage, reinforcing the importance of the pre-operative imaging diagnosis. Although the CT findings of CPA lipomas can be typical, the magnetic resonance (MR) imaging, especially the fat suppression sequences, had improved the identification of these lesions. We aimed to report two patients with a CPA lipoma, emphasizing the MR imaging findings. (author)

Cerebellopontine angle and internal auditory canal: neurovascular anatomy on gas CT cisternograms

International Nuclear Information System (INIS)

Bird, C.R.; Hasso, A.N.; Drayer, B.P.; Hinshaw, D.B. Jr.; Thompson, J.R.

1985-01-01

The authors reviewed 103 normal gas CT cisternograms to delineate the appearance of normal neurovascular structures in the cerebellopontine angle (CPA) and internal auditory canal (IAC). Cranial nerves VII and VIII were identified in the CPA in 97% of cases, either separately (53%) or as a bundle (44%). Intracanalicular branches of the VIIIth cranial nerve were identified in 20% of cases, and cranial nerve V was visualized in the CPA in 14%. The characteristic vascular loop, usually the anterior inferior cerebellar artery, was visible in 35% of cases, and, in 22% of visualized cases, was in an intracanalicular location. In 10% of cases, greater than 66% of the IAC was occupied by the neurovascular bundle. Familiarity with the normal anatomy and variations seen on gas CT cisternograms is necessary to prevent false-positive interpretations

Effective preoperative irradiation of highly vascular cerebellopontine angle neurinomas

International Nuclear Information System (INIS)

Ikeda, K.; Ito, H.; Kashihara, K.; Fujisawa, H.; Yamamoto, S.

1988-01-01

Three cases of large cerebellopontine angle neurinoma with marked vascularity and tumor staining on the angiogram were treated with effective preoperative irradiation. The radiotherapy was given before the second operation in two cases and before the first operation in the other case. Irradiation doses administered with a linear accelerator were 2.34 to 3.0 Gy for 3 to 3.5 weeks, and radical operations were done 1.5 to 2 months after irradiation. After the irradiation, vertebral angiography showed moderate to marked decrease of the hypervascular capsular stain and disappearance of the early draining vein. Computed tomographic scan showed enlargement of the central necrotic area within the heterogeneously enhanced tumor, which was unchanged in size. Radical operations, which had been impossible because of uncontrollable massive bleeding, were successful without any intraoperative bleeding after radiotherapy. Postirradiation radiological findings corresponded well with those of histopathological examination, which showed decrease in cellularity and in vascularity and diffuse coagulation necrosis around the collapsed tumoral vessels as radiation effects. Preoperative irradiation of the hypervascular neurinoma was though to facilitate radical surgery by abolishing or diminishing the risk of intraoperative bleeding

Visualization of cerebellopontine angle lesions by nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

Ochiai, Chikayuki; Takakura, Kintomo; Machida, Tohru; Araki, Tsutomu; Iio, Masahiro; Basugi, Norihiko.

1983-01-01

The preliminary results from the clinical use a prototype whole body nuclear magnetic resonance (NMR) machine constructed by Toshiba Inc. are presented. Cranial NMR scans were performed on more than 30 cases with broad spectrum of neurologic diseases using saturation-recovery and inversion-recovery sequences with a field strength of 1500 Gauss. Selective excitation sequence was used for the slice selection and filtered backprojection was used to reconstruct the images. They were displayed on a 256 x 256 matrix as 12 mm thick sections. Data aquisition time varied between 3 and 12 minutes. Our initial experiences with six cases harboring cerebellopontine angle lesions discolsed advantages and disadvantages of NMR imaging in comparison with X-ray CT. The advantages were the absence of linear artifacts from the surrounding bone, the marked gray-white matter differentiation, and the variety of tomographic planes available. The disadvantages included the lack of bone detail, the lack of visualization of the major intracranial vessels, and the long time required for scanning (several minutes per slice). Although much continued evaluation is necessary, NMR seems to have vast potential as a diagnostic tool. (author)

Teflon granulomas mimicking cerebellopontine angle tumors following microvascular decompression.

Science.gov (United States)

Deep, Nicholas L; Graffeo, Christopher S; Copeland, William R; Link, Michael J; Atkinson, John L; Neff, Brian A; Raghunathan, Aditya; Carlson, Matthew L

2017-03-01

To report two patients with a history of microvascular decompression (MVD) for hemifacial spasm who presented with Teflon granulomas (TG) mimicking cerebellopontine angle (CPA) tumors and to perform a systematic review of the English-language literature. Case series at a single tertiary academic referral center and systematic review. Retrospective chart review with analysis of clinical, radiological, and histopathological findings. Systematic review using PubMed, Embase, MEDLINE, and Web of Science databases. Two patients with large skull base TGs mimicking CPA tumors clinically and radiographically were managed at the authors' institution. The first presented 4 years after MVD with asymmetrical sensorineural hearing loss, multiple progressive cranial neuropathies, and brainstem edema due to a growing TG. Reoperation with resection of the granuloma confirmed a foreign-body reaction consisting of multinucleated giant cells containing intracytoplasmic Teflon particles. The second patient presented 11 years after MVD with asymmetrical sensorineural hearing loss and recurrent hemifacial spasm. No growth was noted over 2 years, and the patient has been managed expectantly. Only one prior case of TG after MVD for hemifacial spasm has been reported in the English literature. TG is a rare complication of MVD for hemifacial spasm. The diagnosis should be suspected in patients presenting with a new-onset enhancing mass of the CPA after MVD, even when performed decades earlier. A thorough clinical and surgical history is critical toward establishing an accurate diagnosis to guide management and prevent unnecessary morbidity. Surgical intervention is not required unless progressive neurologic complications ensue. 4 Laryngoscope, 127:715-719, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Cerebellopontine angle medulloblastoma with extensive nodularity in a child: case report and review of the literature.

Science.gov (United States)

Noiphithak, Raywat; Yindeedej, Vich; Thamwongskul, Chatchai

2017-05-01

Cerebellar medulloblastomas (MBs) are one of the most common posterior fossa tumors in children but rarely occur in the cerebellopontine angle (CPA). Only 39 cases of CPA MBs were reported in the literature, and most of them were classic and desmoplastic MBs. A 22-month-old girl presented with progressive cerebellar ataxia. Magnetic resonance imaging showed a large tumor in the right CPA and obstructive hydrocephalus. Surgical resection was performed and achieved total tumor removal. Microscopic examination and immunohistochemical staining revealed the diagnosis of MB with extensive nodularity. The patient recovered from her symptoms during follow-up and was transferred for adjuvant chemotherapy. MB should be considered as a differential diagnosis of a lesion in the CPA. The treatment and outcome of CPA MBs are similar to cerebellar MBs.

Diffuse arachnoid ossification and multiple arachnoid cysts presenting with progressive thoracic myelopathy

Energy Technology Data Exchange (ETDEWEB)

Sakai, Toshinori; Sairyo, Koichi; Kashima, Masahiro; Kosaka, Hirofumi; Katoh, Shinsuke; Yasui, Natsuo [The University of Tokushima Graduate School, Department of Orthopedics, Institute of Health Biosciences, Tokushima (Japan)

2010-03-15

An ossified arachnoid membrane combined with cystic formation is rarely reported as a cause of spinal cord compression. We report the case of a 60-year-old man who presented with diffuse ossification of the arachnoid membrane (arachnoid ossification) and multiple cystic changes (arachnoid cyst) at the thoracic and lumbar spine. The lesions were surgically removed and progressive deterioration was prevented, although no marked improvement of neurological symptoms was attained. (orig.)

Epidermoid cyst causing hemifacial spasm epidermoid cyst in cerebellopontine angle presenting with hemifacial spasm

Directory of Open Access Journals (Sweden)

Murat Alemdar

2012-01-01

Full Text Available Hemifacial Spasm (HS occurs idiopathically or secondary to the lesions compressing the root exit zone of the facial nerve symptomatically. Symptomatic HS is generally due to vascular compression. We report on a 23-year-old male with right sided HS for a month. Magnetic resonance imaging (MRI of the brain revealed a well-demarcated epidermoid cyst in the right cerebellopontine cistern. It was hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging without contrast enhancement, hyperintense on DWI, and slightly hypointense on ADC relative to the brain. Although it caused shifting of the pons and medulla to the left side and compression of the right cerebellar peduncles and fourth ventricle, the sole symptom of the patient was HS. Clinicians are advised to request MRI/scan for brainstem lesions from the patients with HS. Epidermoid cysts in cerebellopontine cistern may present with HS as the sole symptom.

Reappraisal of cerebellopontine angle medulloblastomas: Report of a fatal case and lessons learned

Directory of Open Access Journals (Sweden)

Sachin Ranganatha Goudihalli, M.Ch. Neurosurgery

2018-06-01

Full Text Available CPA Medulloblastomas are rare in adults. We describe a case of medulloblastoma in the right CPA in a middle aged male patient who presented with short history and was preoperatively diagnosed as vestibular schwannoma. Intra-operatively it turned out to be a highly vascular and malignant lesion. Histopathology demonstrated medulloblastoma with high ki67 index. Patient was re-explored for hematoma evacuation and remained vegetative postoperatively. This is a unique case considering the older age at presentation, short duration of symptoms with atypical presentation of only 7th, 8th and lower cranial nerve involvement. MRI showed a lobulated heterogeneous extra axial right CPA mass lesion extending in the right acoustic meatus and causing mass effect and effacement of the fourth ventricle with heterogeneous enhancement post-gadolinium, suggestive of vestibular schwannoma. The aggressive behaviour of this tumor with short history has to prompt one to keep less common lesions like medulloblastomas as differential diagnosis in the CPA region. Though medulloblastomas are rare lesions in the CPA they have to be considered in the differential diagnosis based on atypical clinical behaviour, a suspicion of such diagnosis preoperatively can alter the treatment strategy, focusing on tumor embolization, safe surgical excision and adjuvant chemoradiation, aiming towards a better quality of life, in the post-operative period. Keywords: Medulloblastoma, Cerebellopontine angle, Desmoplastic

[Arachnoid cysts: Embriology and pathology].

Science.gov (United States)

García-Conde, Mario; Martín-Viota, Lucia

2015-01-01

There is still great controversy surrounding the origin of the arachnoid cyst. The most accepted theory in the case of congenital cysts explains how they are formed from an anomalous development of the arachnoid membrane, which is unfolded allowing the accumulation of cerebrospinal fluid inside and creating a cyst. This theory seems to explain the origin of convexity and sylvian cistern arachnoid cysts, whereas those in other locations might be due to other mechanisms. In the anatomopathological analysis, the arachnoid cyst wall can be seen as having few differences from normal, although thickened due to an increase quantity of collagenous material. A description of the embryological development of the arachnoid layer and cyst formation is presented, describing the main anatomopathological findings. Copyright © 2015 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

CT and MRI characteristica of tumours of the temporal bone and the cerebello-pontine angle

International Nuclear Information System (INIS)

Imhof, H.; Henk, C.B.; Dirisamer, A.; Czerny, C.; Gstoettner, W.

2003-01-01

Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare.This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristica of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fatsuppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spinecho sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spinecho sequences in high resolution technique with fatsuppression after the intravenous application of contrast material will be performed in the coronal plane. HRCT and MRI are both used to depict the most exact tumorous borders. HRCT excellently depicts the osseous changes for example exostosis of the external auditory canal, while also with HRCT osseous changes maybe characterized into more benign or malignant types. MRI has a very high soft tissue contrast and may therefore either characterize vascular space-occupying lesions for example glomus jugulare tumours or may differentiate between more benign or malignant lesions. In conclusion HRCT and MRI of the temporal bone are excellent methods to depict and mostly characterize tumour lesions and can help to differentiate between benign and malignant lesion. These imaging methods shall be used complementary and may have a great impact for the therapeutic planning. (orig.) [de

Spontaneous hygroma in intracranial arachnoid cyst

Energy Technology Data Exchange (ETDEWEB)

Agnoli, A L

1984-06-01

Anamnesis and treatment of two cases of arachnoid cysts extending into the subarachnoid space are described. No traumatic incident was discovered in the previous history of these two patients. The causal genesis of neurological signs of deficiency in patients with arachnoid and acquired cysts is discussed. However, the cause of the development of a subdural hygroma in arachnoid cysts remains unclarified. CT findings of arachnoid cysts with a hypodense zone between brain surface and the vault of the cranium always require an investigation into the possibility of a spontaneous emptying of the cyst or of a congenital and not only localised extension of the cyst itself.

Population study of Pyxis arachnoides brygooi (Vuillemin ...

African Journals Online (AJOL)

The Madagascar spider tortoise (Pyxis arachnoides spp.) is faced with the threat of habitat destruction as well as the international pet trade. Habitat requirements and population structure of this species are largely unknown. Detailed studies have so far concentrated on the subspecies Pyxis arachnoides arachnoides.

[Rare location of arachnoid cysts. Extratemporal cysts].

Science.gov (United States)

Martinez-Perez, Rafael; Hinojosa, José; Pascual, Beatriz; Panaderos, Teresa; Welter, Diego; Muñoz, María J

2016-01-01

The therapeutic management of arachnoid cysts depends largely on its location. Almost 50% of arachnoid cysts are located in the temporal fossa-Sylvian fissure, whereas the other half is distributed in different locations, sometimes exceptional. Under the name of infrequent location arachnoid cysts, a description is presented of those composed of 2 sheets of arachnoid membrane, which are not located in the temporal fossa, and are primary or congenital. Copyright © 2015 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

Spinal extradural arachnoid cysts

Directory of Open Access Journals (Sweden)

Abolfazl Rahimizadeh

2013-01-01

Full Text Available OBJECTIVE: Extradural arachnoid cysts (EACs are rare causes of spinal cord compression and cauda equina. These benign lesions appear in the literature mainly as single case reports. In this article, we present the largest series found in literature, with four new cases of spinal extradural arachnoid cysts. The characteristic imaging features, details of surgical steps and strategies to prevent postoperative kyphosis in this cystic pathology will be discussed.

Sensorineural hearing loss among cerebellopontine-angle tumor patients examined with pure tone audiometry and brainstem-evoked response audiometry

Science.gov (United States)

Rinindra, A. M.; Zizlavsky, S.; Bashiruddin, J.; Aman, R. A.; Wulani, V.; Bardosono, S.

2017-08-01

Tumor in the cerebellopontine angle (CPA) accurs for approximately 5-10% of all intracranial tumors, where unilateral hearing loss and tinnitus are the most frequent symptoms. This study aimed to collect data on sensorineural hearing loss in CPA tumor patients in Dr. Cipto Mangunkusumo Hospital (CMH) using pure tone audiometry and brainstem-evoked response audiometry (BERA). It also aimed to obtaine data on CPA-tumor imaging through magnetic resonance imaging (MRI). This was a descriptive, analytic, and cross-sectional study. The subjects of this study were gathered using a total sampling method from secondary data between July 2012 and November 2016. From 104 patients, 30 matched the inclusion criteria. The CPA-tumor patients in the ENT CMH outpatient clinic were mostly female, middle-aged patients (41-60 years) whose clinical presentation was mostly tinnitus and severe, asymmetric sensorineural hearing loss in 10 subjects. From 30 subjects, 29 showed ipsilaterally impaired BERA results, and 17 subjects showed contralaterally impaired BERA results. There were 24 subjects who with large-sized tumors and 19 subjects who had intracanal tumors that had spread until they were extracanal in 19 subjects.

Preoperative evaluation of neurovascular relationships for microvascular decompression in the cerebellopontine angle in a virtual reality environment.

Science.gov (United States)

Du, Zhuo-Ying; Gao, Xiang; Zhang, Xiao-Luo; Wang, Zhi-Qiu; Tang, Wei-Jun

2010-09-01

In this paper the authors' goal was to evaluate the feasibility and efficacy of a virtual reality (VR) system in preoperative planning for microvascular decompression (MVD) procedures treating idiopathic trigeminal neuralgia and hemifacial spasm. The system's role in surgical simulation and training was also assessed. Between May 2008 and April 2009, the authors used the Dextroscope system to visualize the neurovascular complex and simulate MVD in the cerebellopontine angle in a VR environment in 16 patients (6 patients had trigeminal neuralgia and 10 had hemifacial spasm). Reconstructions were carried out 2-3 days before MVD. Images were printed in a red-blue stereoscopic format for teaching and discussion and were brought into the operating room to be compared with real-time intraoperative findings. The VR environment was a powerful aid for spatial understanding of the neurovascular relationship in MVD for operating surgeons and trainees. Through an initial series of comparison/confirmation experiences, the senior neurosurgeon became accustomed to the system. He could predict intraoperative problems and simulate surgical maneuvering, which increased his confidence in performing the procedure. The Dextroscope system is an easy and rapid method to create a stereoscopic neurovascular model for MVD that is highly concordant with intraoperative findings. It effectively shortens the learning curve and adds to the surgeon's confidence.

Metastatic Extrapulmonary Small Cell Carcinoma to the Cerebellopontine Angle: A Case Report and Review of the Literature

Directory of Open Access Journals (Sweden)

Debebe Theodros

2015-01-01

Full Text Available Extrapulmonary small cell carcinomas (EPSCC are rare malignancies with poor patient prognoses. We present the case of a 63-year-old male who underwent surgical resection of a poorly differentiated small cell carcinoma, likely from a small intestinal primary tumor that metastasized to the cerebellopontine angle (CPA. A 63-year-old male presented with mild left facial paralysis, hearing loss, and balance instability. MRI revealed a 15 mm mass in the left CPA involving the internal auditory canal consistent with a vestibular schwannoma. Preoperative MRI eight weeks later demonstrated marked enlargement to 35 mm. The patient underwent a suboccipital craniectomy and the mass was grossly different visually and in consistency from a standard vestibular schwannoma. The final pathology revealed a poorly differentiated small cell carcinoma. Postoperative PET scan identified avid uptake in the small intestine suggestive of either a small intestinal primary tumor or additional metastatic disease. The patient underwent whole brain radiation therapy and chemotherapy and at last follow-up demonstrated improvement in his symptoms. Surgical resection and radiotherapy are potential treatment options to improve survival in patients diagnosed with NET brain metastases. We present the first documented case of skull base metastasis of a poorly differentiated small cell carcinoma involving the CPA.

Supratentorial arachnoid cyst and associated subdural hematoma: neuroradiologic studies

Energy Technology Data Exchange (ETDEWEB)

Ochi, M. [Dept. of Radiology, Nagasaki Univ. School of Medicine, (Japan); Morikawa, M. [Dept. of Radiology, Nagasaki Univ. School of Medicine, (Japan)]|[Dept. of Radiology, National Nagasaki Chuo Hospital, Ohmura (Japan); Ogino, A. [Dept. of Radiology, Nagasaki Univ. School of Medicine, (Japan); Nagaoki, K. [Dept. of Radiology, Nagasaki Univ. School of Medicine, (Japan)]|[Dept. of Radiology, Isahaya General Hospital (Japan); Hayashi, K. [Dept. of Radiology, Nagasaki Univ. School of Medicine, (Japan)

1996-10-01

CT and MR images of 8 patients with supratentorial arachnoid cyst complicated by subdural hematoma were studied and compared with those of 8 patients who developed nontraumatic subdural hematoma without arachnoid cyst. Ot the 8 patients with supratentorial arachnoid cyst, CT and MR disclosed temporal bulging and/or thinning of the temporal squama in all 6 patients with middle fossa arachnoid cysts, and the thinning of the calvaria was evident in another patient with a convexity cyst. Calvarial thinning at the site corresponding to interhemispheric arachnoid cyst was clearly depicted on coronal MR images. In contrast, none of the 8 young patients with nontraumatic subdural hematoma without arachnoid cyst had abnormal calvaria. Temporal bulging and thinning of the overlying calvaria were identified as diagnostic CT and MR features of arachnoid cyst with complicating intracystic and subdural hermorrhage. Radiologists should be aware of this association and should evaluate the bony structure carefully. (orig.)

Prenatal diagnosis of arachnoid cyst

Directory of Open Access Journals (Sweden)

Korkut Daglar

2016-12-01

Full Text Available Arachnoid cysts are rare, usually benign, space-occupying central nervous system lesion. They are the results of an accumulation of cerebrospinal-like fluid between the cerebral meninges and diagnosed prenatally as a unilocular, simple, echolucent area within the fetal head. They may be primary (congenital (maldevelopment of the meninges or secondary (acquired (result of infection trauma, or hemorrhage. The primary ones typically dont communicate with the subarachnoid space whereas acquired forms usually communicate. In recent years, with the development of radiological techniques, the clinical detectability of arachnoid cysts seems to have increased. We report a case of primary arachnoid cyst that were diagnosed prenatally by using ultrasonography and magnetic resonance imaging . [Cukurova Med J 2016; 41(4.000: 792-795

arachnoiditis

African Journals Online (AJOL)

2005-09-02

Sep 2, 2005 ... Society U K. 1978; 98(4): 490-3. 12. McFadzean RM, Hardly DM, McIlwaine GG. Optochiasmal arachnoiditis following muslin wrapping of ruptured anterior communicating artery aneurysms. J Neurosurg. 1991 Sep; 75 (3):. 393-6. 13. Repka MX, Miller NR, Penix JO, Trant JH 3rd. Optic neuropathy from the.

Arachnoid granulation affected by subarachnoid hemorrhage

Directory of Open Access Journals (Sweden)

R.P. Chopard

1993-11-01

Full Text Available The purpose of this study was to investigate using light microscopy the fibro-cellular components of arachnoid granulations affected by mild and severe subarachnoid hemorrage. The erythrocytes were in the channels delimitated by collagenous and elastic bundles and arachnoid cells, showing their tortuous and intercommunicating row from the pedicle to the fibrous capsule. The core portion of the pedicle and the center represented a principal route to the bulk outflow of cerebrospinal fluid and erythrocytes. In the severe hemorrhage, the fibrocellular components are desorganized, increasing the extracellular channels. We could see arachnoid granulations without erythrocytes, which cells showed big round nucleous suggesting their transformation into phagocytic cells.

Pathology of the vestibulocochlear nerve

Energy Technology Data Exchange (ETDEWEB)

De Foer, Bert [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: bert.defoer@GZA.be; Kenis, Christoph [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: christophkenis@hotmail.com; Van Melkebeke, Deborah [Department of Neurology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Deborah.vanmelkebeke@Ugent.be; Vercruysse, Jean-Philippe [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: jphver@yahoo.com; Somers, Thomas [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Thomas.somers@GZA.be; Pouillon, Marc [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: marc.pouillon@GZA.be; Offeciers, Erwin [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Erwin.offeciers@GZA.be; Casselman, Jan W. [Department of Radiology, AZ Sint-Jan AV Hospital, Ruddershove 10, Bruges (Belgium); Consultant Radiologist, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium); Academic Consultent, University of Ghent (Belgium)], E-mail: jan.casselman@azbrugge.be

2010-05-15

There is a large scala of pathology affecting the vestibulocochlear nerve. Magnetic resonance imaging is the method of choice for the investigation of pathology of the vestibulocochlear nerve. Congenital pathology mainly consists of agenesis or hypoplasia of the vestibulocochlear nerve. Tumoral pathology affecting the vestibulocochlear nerve is most frequently located in the internal auditory canal or cerebellopontine angle. Schwannoma of the vestibulocochlear nerve is the most frequently found tumoral lesion followed by meningeoma, arachnoid cyst and epidermoid cyst. The most frequently encountered pathologies as well as some more rare entities are discussed in this chapter.

Pathology of the vestibulocochlear nerve

International Nuclear Information System (INIS)

De Foer, Bert; Kenis, Christoph; Van Melkebeke, Deborah; Vercruysse, Jean-Philippe; Somers, Thomas; Pouillon, Marc; Offeciers, Erwin; Casselman, Jan W.

2010-01-01

There is a large scala of pathology affecting the vestibulocochlear nerve. Magnetic resonance imaging is the method of choice for the investigation of pathology of the vestibulocochlear nerve. Congenital pathology mainly consists of agenesis or hypoplasia of the vestibulocochlear nerve. Tumoral pathology affecting the vestibulocochlear nerve is most frequently located in the internal auditory canal or cerebellopontine angle. Schwannoma of the vestibulocochlear nerve is the most frequently found tumoral lesion followed by meningeoma, arachnoid cyst and epidermoid cyst. The most frequently encountered pathologies as well as some more rare entities are discussed in this chapter.

Arachnoid cyst in cavernous sinus: case report

International Nuclear Information System (INIS)

Lim, Hyoung Gun; Yoo, Won Jong; Jung, So Lyung; Lee, Hae Gui; Lim, Hyun Wook; Im, Soo Ah

2002-01-01

Arachnoid cyst of the cavernous sinus is very rare. When present, its anatomic location frequently gives rise to cranial nerve palsy. We report a case of arachnoid cyst of the cavernous sinus in a 38-year-old man with impaired eyeball movement and diplopia

Arachnoid cyst in cavernous sinus: case report

International Nuclear Information System (INIS)

Lim, Hyoung Gun; Yoo, Won Jong; Jung, So Lyung; Lee, Hae Giu; Lim, Hyun Wook; Im, Soo Ah

2002-01-01

Arachnoid cyst of the cavernous sinus is very rare. When present, its anatomic location frequently gives rise to cranial nerve palsy. We report a case of arachnoid cyst of the cavernous sinus in a 38-year-old man with impeder eyeball movement and diplopia

Arachnoid cyst in cavernous sinus: case report

Energy Technology Data Exchange (ETDEWEB)

Lim, Hyoung Gun; Yoo, Won Jong; Jung, So Lyung; Lee, Hae Giu; Lim, Hyun Wook; Im, Soo Ah [The Catholic University of Kore College of Medicine, Puchun (Korea, Republic of)

2002-12-01

Arachnoid cyst of the cavernous sinus is very rare. When present, its anatomic location frequently gives rise to cranial nerve palsy. We report a case of arachnoid cyst of the cavernous sinus in a 38-year-old man with impeder eyeball movement and diplopia.

An interesting case of primary spinal arachnoiditis.

LENUS (Irish Health Repository)

Vaughan, Denis

2012-02-27

Spinal arachnoiditis describes inflammation of the meninges, subarachnoid space and, in most cases, also involve the pial layer. The vast majority of cases described are secondary and are preceded by a known event, for example,. trauma, infections or irritative substances. Here, we present the case of primary spinal arachnoiditis. A 35-year-old lady was referred to the neurosurgical services in Dublin, Ireland with a 15-month history of progressive, right lower limb weakness. Magnetic resonance imaging revealed cystic distortion of the lumbar spinal canal extending up to the conus. Initially, an L2-L4 laminectomy was performed revealing thickened and adherent arachnoid with a large cyst in the spinal canal. Four months after initial operation, the patient represented with bilateral lower limb weakness and loss of detrusor function. Repeat magnetic resonance imaging was performed, which showed the development of a syrinx in the patient\\'s thoracic spine. We then performed a T9-T10 laminectomy, midline myelotomy and insertion of a syringe-arachnoid shunt. Post-operative imaging showed resolution of the syrinx and a vast improvement in lower limb power. The patient also regained bladder control. In conclusion, spinal arachnoiditis is a clearly defined pathological and radiological entity with a highly variable clinical presentation. It is exceedingly difficult to treat as there is no recognised treatment currently, with most interventions aimed at symptomatic relief.

Giant non traumatic intradiploic arachnoid cyst in a young male

Energy Technology Data Exchange (ETDEWEB)

Sharma, Rajesh [Department of Radiodiagnosis and Imaging, ASCOMS Hospital, Sidhra, Jammu (India); Gupta, Puneet; Mahajan, Manik, E-mail: puneetgupta619@yahoo.com [Department of Radiodiagnosis and Imaging, Lady Hardinge Medical College, New Delhi (India); Sharma, Poonam [Department of Pathology, GMC, Jammu (India); Gupta, Anchal; Khurana, Arti [Department of Radiodiagnosis and Imaging, GMC, Jammu (J and K) (India)

2016-09-15

Intradiploic arachnoid cysts have scarcely been reported in the literature, most reported cases being secondary to trauma. Non traumatic arachnoid cysts are quite rare and have been reported mostly in adults. Here, we report the case of a 16-year-old male presenting with a slowly growing mass in the occipital region and intermittent headaches. On the basis of the findings of X-rays, computed tomography scans, and magnetic resonance imaging scans of the head, the mass was diagnosed as a giant intradiploic arachnoid cyst. Keywords: Arachnoid cysts; Cerebrospinal fluid; Headache/diagnosis. (author)

Radiological indeterminate vestibular schwannoma and meningioma in cerebellopontine angle area: differentiating using whole-tumor histogram analysis of apparent diffusion coefficient.

Science.gov (United States)

Xu, Xiao-Quan; Li, Yan; Hong, Xun-Ning; Wu, Fei-Yun; Shi, Hai-Bin

2017-02-01

To assess the role of whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating radiological indeterminate vestibular schwannoma (VS) from meningioma in cerebellopontine angle (CPA). Diffusion-weighted (DW) images (b = 0 and 1000 s/mm 2 ) of pathologically confirmed and radiological indeterminate CPA meningioma (CPAM) (n = 27) and VS (n = 12) were retrospectively collected and processed with mono-exponential model. Whole-tumor regions of interest were drawn on all slices of the ADC maps to obtain histogram parameters, including the mean ADC (ADC mean ), median ADC (ADC median ), 10th/25th/75th/90th percentile ADC (ADC 10 , ADC 25 , ADC 75 and ADC 90 ), skewness and kurtosis. The differences of ADC histogram parameters between CPAM and VS were compared using unpaired t-test. Multiple receiver operating characteristic (ROC) curves analysis was used to determine and compare the diagnostic value of each significant parameter. Significant differences were found on the ADC mean , ADC median , ADC 10 , ADC 25 , ADC 75 and ADC 90 between CPAM and VS (all p values Histogram analysis of ADC maps based on whole tumor can be a useful tool for differentiating radiological indeterminate CPAM from VS. The ADC 90 value was the most promising parameter for differentiating these two entities.

THE DIAGNOSIS AND TREATMENT OF INTRACRANIAL ARACHNOID CYSTS

NARCIS (Netherlands)

GO, KG

Intracranial arachnoid cysts have been found in 0.3% of computed tomography (CT) scans and in 0.1% of brain autopsy specimens, more often in children than in adults. Intracranial arachnoid cysts occur prevalently in males, on the left side, and in the temporal fossa. Their occasional association

Epidermoid cyst in the cerebellopontine angle cistern presenting as trigeminal neuralgia. Diagnostic values of the orbicularis oculi reflex and metrizamide CT cisternography - case report -

Energy Technology Data Exchange (ETDEWEB)

Ueda, Takashi; Goya, Tomokazu; Kinoshita, Kazuo (Miyazaki Medical College, Miyazaki (Japan)); Fukui, Masashi

1983-05-01

This 29-year-old male had been suffering from left trigeminal neuralgia one year prior to admission. Admission was prompted by the development of pain in the third division of the left trigeminal nerve. Physical and neurological examinations were not remarkable except for the facial pain. The orbicularis oculi reflex showed delayed latency of R/sub 1/ on the affected side. CT scans performed pre- and post-contrast enhancement revealed a low density area in the left cerebellopontine angle cistern. Metrizamide CT cisternography clearly revealed the margin of the lesion as the contrast media did not enter into the low density area. A left suboccipital craniectomy was performed. The trigeminal nerve was surrounded by a thin-capsulated mass and cholesteatoma materials. Histological diagnosis was epidermoid cyst. Since this surgical procedure, the trigeminal neuralgia has not recurred for one year. Without objective neurological deficits, it is difficult to distinguish symptomatic trigeminal from idiopathic neuralgia. Therefore, minor change of the orbicularis oculi reflex should help in objectively detecting dysfunction of the trigeminal nerve. Metrizamide CT cisternography is also useful in diagnosis of cystic lesions.

Tuberculous radiculomyelitis (arachnoiditis): myelographic (and CT myelographic) appearances

International Nuclear Information System (INIS)

Phadke, R.V.; Kohli, A.; Jain, V.K.; Gupta, R.K.; Gujral, R.B.

1994-01-01

Tuberculous radiculomyelitis (arachnoiditis) remains one of the important causes of paraplegia in India. The diagnosis usually rests on clinical history and examination, and on laboratory findings in the cerebro-spinal fluid (CSF). Few descriptive reports are available of the myelographic appearance, with water-soluble contrast media, in tuberculous radiculomyelitis (arachnoiditis). A retrospective review of 21 myelograms and 10 computed tomographic (CT) myelograms, in 14 patients with tuberculous radiculomyelitis, was carried out, with a view to describing, in detail, the radiographic features. An attempt was made to assess the use of the radiologic procedures in diagnosis and follow up in these patients. Conventional myelographic findings included block (8/14), irregular sub-arachnoid space (9/14), filling defects (8/14), sluggish contrast flow (2/14), root thickening (3/14) and atrophic cord (2/14). Computed tomographic myelography showed reduced contrast density in portions of the opacified CSF ring around the cord in affected region (6/7) and, in addition, demonstrated septa and adhesions. Intravenous contrast CT was not found to be useful (2/2). Follow-up studies showed partial resolution (3/6), deterioration (1/6) and status quo of radiological findings (2/6). Although these changes can be seen in chronic radiculomyelitis (arachnoiditis) from other causes, such as leukaemic infiltration/lymphoma, other chronic central nervous system infections and iatrogenic causes, including repeated intrathecal injections, conventional myelography appeared to be useful for diagnosis and follow up in tuberculous radiculomyelitis (arachnoiditis). 12 refs., 1 tabs., 10 figs

Spontaneous disappearance of two asymptomatic arachnoid cysts in two different locations.

Science.gov (United States)

Cokluk, C; Senel, A; Celik, F; Ergür, H

2003-04-01

We report two children with asymptomatic arachnoid cysts which resolved spontaneously without any surgical intervention and history of major head and body trauma. The first child was a 10-year-old boy with an arachnoid cyst in the right sylvian fissure. The second child was a 1-year-old girl with a right cerebral convexity arachnoid cyst. Both of them were asymptomatic. Arachnoid cysts spontaneously disappeared within 2 years following initial diagnosing. There was no major head and body trauma except usual home, school and sports activity. We speculated that the cysts ruptured into cerebrospinal fluid circulation by the mechanical effects of some forced activities to the brain tissue and cyst, such as excessive breathing, coughing and sport activities. These factors may change the balance between intracystic and pericystic pressure and facilitate the rupturing of the cyst into subdural, subarachnoid and intraventricular spaces. These cases demonstrate that neurosurgical intervention of asymptomatic arachnoid cysts is not absolutely indicated in the paediatric age group. Close follow up with computerized tomography (CT) and magnetic resonance imaging (MRI) is a treatment option in the patient with arachnoid cysts located in the middle cranial fossa and cerebral convexity.

Intracranial aneurysm and arachnoid cyst: just a coincidence? A case report.

Science.gov (United States)

Aguiar, Guilherme Brasileiro de; Santos, Rafael Gomes Dos; Paiva, Aline Lariessy Campos; Silva, João Miguel de Almeida; Silva, Rafael Carlos da; Veiga, José Carlos Esteves

2017-12-18

Presence of an arachnoid cyst and a non-ruptured intracystic brain aneurysm is extremely rare. The aim of this paper was to describe a case of a patient with an arachnoid cyst and a non-ruptured aneurysm inside it. Clinical, surgical and radiological data were analyzed and the literature was reviewed. A patient complained of chronic headache. She was diagnosed as having a temporal arachnoid cyst and a non-ruptured middle cerebral artery aneurysm inside it. Surgery was performed to clip the aneurysm and fenestrate the cyst. This report raises awareness about the importance of intracranial vascular investigation in patients with arachnoid cysts and brain hemorrhage.

Giant arachnoid granulation in a patient with benign intracranial hypertension

Energy Technology Data Exchange (ETDEWEB)

Kiroglu, Yilmaz; Yaqci, Baki; Cirak, Bayram; Karabulut, Nevzat [Pamukkale University, Department of Radiology, School of Medicine, Denizli (Turkey)

2008-10-15

We report magnetic resonance (MR), computed tomography (CT) and angiographic imaging of an unusual giant arachnoid granulation in the superior sagittal sinus in a man with headache and vertigo. Intrasinus pressure measurements revealed a significant pressure gradient across the lesion. MR imaging is useful to identify giant arachnoid granulation and dural sinus thrombosis, whereas dural sinus pressure measurement in certain cases of giant arachnoid granulations can be used to evaluate the lesion as the cause of the patient's symptoms. (orig.)

Giant arachnoid granulation in a patient with benign intracranial hypertension

International Nuclear Information System (INIS)

Kiroglu, Yilmaz; Yaqci, Baki; Cirak, Bayram; Karabulut, Nevzat

2008-01-01

We report magnetic resonance (MR), computed tomography (CT) and angiographic imaging of an unusual giant arachnoid granulation in the superior sagittal sinus in a man with headache and vertigo. Intrasinus pressure measurements revealed a significant pressure gradient across the lesion. MR imaging is useful to identify giant arachnoid granulation and dural sinus thrombosis, whereas dural sinus pressure measurement in certain cases of giant arachnoid granulations can be used to evaluate the lesion as the cause of the patient's symptoms. (orig.)

Lumbosacral arachnoid cyst with tethered cord: A rare case report

Directory of Open Access Journals (Sweden)

S K Jain

2012-01-01

Full Text Available Arachnoid cysts are cerebrospinal fluid collections in the spine that can present with neurological symptoms or be discovered accidentally. Intradural location of such cysts especially in the lumbosacral region is relatively rare. The association of such cysts with other congenital anomalies such as tethered cord lends evidence to the developmental origin of arachnoid cysts. We report a case of lumbosacral arachnoid cyst with tethered cord in a 6-year-old male child and discuss the etiopathogenesis and management options.

MR imaging of syringomyelia secondary to arachnoid adhesions

International Nuclear Information System (INIS)

Mark, A.S.; Andrews, B.; Sanches, J.; Manelfe, C.; Norman, D.; Newton, T.H.

1987-01-01

Arachnoid adhesions have been recognized as a cause of syringomyelia. Ten patients with surgically proven syringomyelia secondary to arachnoid adhesions (seven postraumatic, two postinfectious, one post-Pantopaque) were examined by MR imaging using sagittal and axial T1-weighted and sagittal T2-weighted sequences. A syrinx with loss of the sharp edge between the cord and the subarachnoid space as compared with the sharp interface seen in syringomyelia associated with Chiari I, was demonstrated on T1-weighted sequences in all patients. Intradural arachnoid cysts were found in nine patients. After surgical fenestration of the cyst, four patients improved and five remained unchanged. In one patient the syrinx decreased after fenestration of the cyst. Early detection and fesestration of these cavities may improve the patients' outcome

A Rare Case of Radiologically Not Distinguishable Coexistent Meningioma and Vestibular Schwannoma in the Cerebellopontine Angle – Case Report and Literature Review

Directory of Open Access Journals (Sweden)

Juergen Grauvogel

2010-08-01

Full Text Available Background: The simultaneous occurrence of cerebellopontine angle (CPA meningioma and vestibular schwannoma (VS in the absence of neurofibromatosis type 2 or history of irradiation is very rare. We report a case with coexistent CPA meningioma and VS, which were radiologically not distinguishable in preoperative imaging. Case Description: A 46-year-old female presented with acute hearing loss, tinnitus and gait ataxia. Otorhinolaryngological diagnostic workup and imaging studies showed an intra- and extrameatal homogenous contrast enhancing lesion. The neuroradiological diagnosis was VS. The patient was operated via the retrosigmoid approach. Intraoperatively two distinct tumors were found: a small, mainly intrameatally located VS and a larger meningioma originating from the dura of the petrous bone. Both tumors were completely microsurgically removed. The patient experienced no new neurological deficit after surgery; particularly facial nerve function was completely preserved. Histopathological examination revealed a fibromatous meningioma and a VS, respectively. Conclusions: The coincidental occurrence of CPA meningioma and VS is very rare. Careful interpretation of imaging studies before surgery is crucial. Even such rare cases should be kept in mind when discussing the therapeutic options with the patient. More studies are needed for a better understanding of mechanisms leading to multiple tumor growth.

Does the location of a vascular loop in the cerebellopontine angle explain pulsatile and non-pulsatile tinnitus?

International Nuclear Information System (INIS)

Nowe, V.; Wang, X.L.; Gielen, J.; Goethem, J.Van; Oezsarlak, Oe.; De Schepper, A.M.; Parizel, P.M.; Ridder, D. De; Heyning, P.H.Van de

2004-01-01

The purpose was to investigate patients with unexplained pulsatile and non-pulsatile tinnitus by means of MR imaging of the cerebellopontine angle (CPA) and to correlate the clinical subtype of tinnitus with the location of a blood vessel (in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve). Clinical presentation of tinnitus and perceptive hearing loss were correlated. In 47 patients with unexplained tinnitus, an MR examination of the CPA was performed. Virtual endoscopy reconstructions were obtained using a 3D axial thin-section high-resolution heavily T2-weighted gradient echo constructive interference in steady state (CISS) data-set. High-resolution T2-weighted CISS images showed a significantly higher number of vascular loops in the internal auditory canal in patients with arterial pulsatile tinnitus compared to patients with non-pulsatile tinnitus (P<0.00001). Virtual endoscopy images were used to investigate vascular contacts at the cisternal part of the VIIIth cranial nerve in patients with low pitch and high pitch non-pulsatile tinnitus. A significantly different distribution of the vascular contacts (P=0.0320) was found. Furthermore, a correlation between the clinical presentation of non-pulsatile tinnitus (high pitch and low pitch) and the perceptive hearing loss was found (P=0.0235). High-resolution heavily T2-weighted CISS images and virtual endoscopy of the CPA can be used to evaluate whether a vascular contact is present in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve and whether the location of the vascular contact correlates with the clinical subtype of tinnitus. Our findings suggest that there is a tonotopical structure of the cisternal part of the VIIIth cranial nerve. A correlation between the clinical presentation of tinnitus and hearing loss was found. (orig.)

Does the location of a vascular loop in the cerebellopontine angle explain pulsatile and non-pulsatile tinnitus?

Energy Technology Data Exchange (ETDEWEB)

Nowe, V; Wang, X L; Gielen, J; Goethem, J Van; Oezsarlak, Oe; De Schepper, A M; Parizel, P M [University of Antwerp, Department of Radiology, Edegem (Belgium); Ridder, D De [University of Antwerp, Department of Neurosurgery, Edegem (Belgium); Heyning, P.H.Van de [University of Antwerp, Department of Otorhinolaryngology, Edegem (Belgium)

2004-12-01

The purpose was to investigate patients with unexplained pulsatile and non-pulsatile tinnitus by means of MR imaging of the cerebellopontine angle (CPA) and to correlate the clinical subtype of tinnitus with the location of a blood vessel (in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve). Clinical presentation of tinnitus and perceptive hearing loss were correlated. In 47 patients with unexplained tinnitus, an MR examination of the CPA was performed. Virtual endoscopy reconstructions were obtained using a 3D axial thin-section high-resolution heavily T2-weighted gradient echo constructive interference in steady state (CISS) data-set. High-resolution T2-weighted CISS images showed a significantly higher number of vascular loops in the internal auditory canal in patients with arterial pulsatile tinnitus compared to patients with non-pulsatile tinnitus (P<0.00001). Virtual endoscopy images were used to investigate vascular contacts at the cisternal part of the VIIIth cranial nerve in patients with low pitch and high pitch non-pulsatile tinnitus. A significantly different distribution of the vascular contacts (P=0.0320) was found. Furthermore, a correlation between the clinical presentation of non-pulsatile tinnitus (high pitch and low pitch) and the perceptive hearing loss was found (P=0.0235). High-resolution heavily T2-weighted CISS images and virtual endoscopy of the CPA can be used to evaluate whether a vascular contact is present in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve and whether the location of the vascular contact correlates with the clinical subtype of tinnitus. Our findings suggest that there is a tonotopical structure of the cisternal part of the VIIIth cranial nerve. A correlation between the clinical presentation of tinnitus and hearing loss was found. (orig.)

Magnetic resonance cisternography for preoperative evaluation of arachnoid cysts

Energy Technology Data Exchange (ETDEWEB)

Awaji, M. [Niigata University, Department of Radiology, Faculty of Medicine, Niigata (Japan); Okamoto, K. [Niigata University, Center for Integrated Human Brain Science, Brain Research Institute, Niigata (Japan); Nishiyama, K. [Niigata University, Department of Neurosurgery, Brain Research Institute, Niigata (Japan)

2007-09-15

With a high likelihood of clinical improvement and low rates of complications, minimally invasive neuroendoscopic surgery is becoming the treatment of choice for symptomatic or growing arachnoid cysts. In neuroendoscopic surgery, visualization of anatomical landmarks is essential in achieving successful fenestration without complications. Because of the restricted visual field in neuroendoscopic surgery, preoperative anatomical assessment is very helpful. Magnetic resonance cisternography (MRC) with high spatial resolution and contrast, using for example 3-D Fourier transformation constructive interference in steady state (CISS) or fast imaging employing steady-state acquisition (FIESTA) sequences, is able to detect the arachnoid cyst wall and neighboring anatomical structures as the anatomical landmarks. We retrospectively reviewed T2-weighted (T2-W) fast spin-echo images, and the MRC and intraoperative findings. Axial and coronal T2-W images (6 and 3 mm thickness, respectively) and axial and coronal 0.8 mm thick MRC images with CISS or FIESTA were obtained from four patients with arachnoid cysts treated by neuroendoscopic surgery. Intraoperative findings were reviewed on videotape recorded during the procedures. At the brain surface, the arachnoid cyst wall could be detected clearly in any of the four patients on MRC images, and was only partly seen in the fourth patient T2-W images. Adjacent important anatomical structures including vessels and cranial nerves, and an enough space for cystocisternostomy were identified on MRC images, and the findings were consistent with the findings during neuroendoscopic surgery. Preoperative identification of the arachnoid cyst wall and surrounding anatomical structures by MRC may help avoid complications and allow safer neuroendoscopic surgery. (orig.)

Large intradural craniospinal arachnoid cyst: A case report and review of literature

Directory of Open Access Journals (Sweden)

Souvagya Panigrahi

2012-01-01

Full Text Available Presence of an arachnoid cyst at craniospinal junction is not very common. This is a very rare anatomic site, with only seven other cases reported in the literature. We report a case of large intradural craniospinal arachnoid cyst presenting with obstructive hydrocephalus and cranial nerve palsy. A 39-year-old male presented with 8-month history of neck pain, headache, vomiting, visual disturbances, diminished taste sensation, and numbness of face. He had bilateral papilledema on ophthalmoscopy. Magnetic resonance imaging (MRI revealed a posterior fossa arachnoid cyst extending down to the lower border of C5 vertebra. Posterior decompression was done through C5 laminectomy. He made a full recovery and was asymptomatic at 6-month follow-up examination. The clinical features, diagnosis, and management of these rare craniospinal arachnoid cysts are discussed.

Strategic Management of Cerebral Arachnoid Cysts in Children in the Era of Globalisation

Directory of Open Access Journals (Sweden)

Eva-Maria COJOCARU

2017-06-01

Full Text Available Introduction: Arachnoid cysts in children are incidental or symptomatic findings which can have associated neurological pathologies in children. Epileptic seizures and headache are by far the most common symptoms associated to arachnoid cysts but they can also associate cerebral palsy or facial dwarfism. Objectives: In the era of globalisation we want to highlight the importance of modern diagnostic procedures and long term strategic management of children with arachnoid cysts in order to rise their social competence and have a better quality of life. Material and methods: We searched the most important theories in the literature and the new methods in the management of the arachnoid cysts. Results: Even if surgical is necessary just in few cases, medication is needed for epileptic seizures. Many children receive neuroprotective agents while other receive antiepileptic drugs for the concomitant or associated epilepsy. For speech difficulties and movement disorders speech therapy, physical therapy and other further support is needed. Discussions and conclusions: The EEG patterns are not mandatory identic to the site of the cyst. Facial dwarfism and other genetic hallmarks need to be further investigated for rare syndromes associated to cerebral arachnoid cysts. The arachnoid cyst could be a hallmark that children brain can be more sensitive to seizures.

Chronic subdural hematoma associated with arachnoid cyst. Two case histories with pathological observations.

Science.gov (United States)

Takayasu, Takeshi; Harada, Kunyu; Nishimura, Shigeru; Onda, Jun; Nishi, Tohru; Takagaki, Hisashi

2012-01-01

Arachnoid cysts are well known to induce chronic subdural hematoma (CSDH) after head injury. However, histological observations of the arachnoid cyst and hematoma membrane have only been rarely described. An 8-year-old boy and a 3-year-old boy presented with CSDH associated with arachnoid cyst. Surgical removal of the hematoma and biopsy of the hematoma membrane and cyst wall were performed. Clinical courses were good and without recurrence more than 1.5 years after surgery. Histological examination suggested that the cysts did not contribute to hematoma development. Pediatric hematoma membranes, similar to adult hematoma membranes, are key in the growth of CSDH. Therefore, simple hematoma evacuation is adequate as a first operation for CSDH associated with arachnoid cyst.

Giant arachnoid granulation: differential diagnosis of acute headache

International Nuclear Information System (INIS)

Peters, S.A.; Heyer, C.M.; Frombach, E.

2007-01-01

Full text: We present a case of intense, rapidly evolving headache clinically mimicking meningitis, subarachnoid haemorrhage or venous sinus thrombosis. Clinical examination, standard blood work and central nervous system studies were non-contributory and effectively ruled out these diagnoses. Cranial multidetector CT studies before and after application of intravenous contrast medium performed prior to lumbar tap disclosed a non-enhancing ovoid mass filling the superior sagittal sinus. This lesion posed a differential to venous sinus thrombosis, but ultimately fulfilled the criteria of a giant arachnoid granulation. The imaging characteristics and differential diagnosis of giant arachnoid granulations are discussed

Role of MR imaging in the diagnosis of complicated arachnoid cyst

Energy Technology Data Exchange (ETDEWEB)

Ibarra, R.; Kesava, P.P. [Dept. of Radiology, University of Texas, San Antonio, TX (United States)

2000-05-01

Background. Arachnoid cysts are intra-arachnoidal cerebrospinal fluid collections that are usually asymptomatic, however, they may become acutely symptomatic due to enlargement of the cyst or the presence of hemorrhage. Materials and methods. We report a case of a child presenting with a 3-week history of headaches, nausea, and vision problems. There was no history of trauma. MRI clearly demonstrated a left middle cranial fossa arachnoid cyst with associated subacute intracystic and subdural hematoma that was causing mass effect and required surgery. Results. This lesion was isodense to the brain on CT. Conclusion. We focus on the importance of MR imaging in the differentiation of these subacute/early chronic hemorrhagic collections that may be overlooked with CT. (orig.)

Role of MR imaging in the diagnosis of complicated arachnoid cyst

International Nuclear Information System (INIS)

Ibarra, R.; Kesava, P.P.

2000-01-01

Background. Arachnoid cysts are intra-arachnoidal cerebrospinal fluid collections that are usually asymptomatic, however, they may become acutely symptomatic due to enlargement of the cyst or the presence of hemorrhage. Materials and methods. We report a case of a child presenting with a 3-week history of headaches, nausea, and vision problems. There was no history of trauma. MRI clearly demonstrated a left middle cranial fossa arachnoid cyst with associated subacute intracystic and subdural hematoma that was causing mass effect and required surgery. Results. This lesion was isodense to the brain on CT. Conclusion. We focus on the importance of MR imaging in the differentiation of these subacute/early chronic hemorrhagic collections that may be overlooked with CT. (orig.)

Brown-Séquard syndrome following intracranial subarachnoid hemorrhage-induced spinal arachnoid cyst

Directory of Open Access Journals (Sweden)

Yew-Weng Fong

2017-12-01

Full Text Available Objective: Arachnoid cyst associated with spinal arachnoiditis following subarachnoid hemorrhage (SAH is a rare complication. Correctly diagnosing this condition and providing an effective treatment are extremely important. Case report: A 60-year-old women had a history of SAH due to an intradural vertebral artery dissecting aneurysm post-coil embolization, without neurologic deficits on discharge from our institution. She experienced left hemiparesis with muscle power graded at 4/5 eight months later due to a right middle cerebral artery territory infarct. Nine months after stroke rehabilitation, there was a progression of left-side weakness and right-side numbness down below the nipple level. On neurological examination, there were right sensory deficits below T6, and left hemiparesis with muscle power of the left upper extremity graded at 4/5 and that of the left lower extremity graded at 3/5. Deep tendon reflex was symmetrically increased at the bilateral lower extremities. Spinal magnetic resonance imaging (MRI revealed a cervicothoracic multiseptated arachnoid cyst with a major compression effect at T6. Eight months after T5–6 hemilaminectomy and fenestration of the cyst wall, the neurologic deficits had not improved. The patient then underwent a cysto-peritoneal shunt. A follow-up MRI documented a complete resolution of the arachnoid cyst. The patient's Brown-Séquard syndrome showed clinical improvement. Conclusion: Prompt investigation revealed a spinal arachnoid cyst in a patient with a history of intracranial SAH presenting with unexplained progressive Brown-Séquard syndrome. For cases of multiseptated and long arachnoid cyst, as in our patient, a shunting procedure is a better choice than fenestration alone.

Dual lumbar bronchogenic and arachnoid cyst presenting with sciatica and left foot drop.

Science.gov (United States)

Candy, Nicholas; Young, Adam; Devadass, Abel; Dean, Andrew; McMillen, Jason; Trivedi, Rikin

2017-10-01

Spinal bronchogenic cysts are rare findings, with only four cases of lumbar bronchogenic cysts reported in the literature. All of these bronchogenic cysts involved the conus medullaris. We present the first case of a lumbar bronchogenic cyst and arachnoid cyst arising from the cauda equina in a 68-year-old male. Uniquely, this bronchogenic cyst also contained components of an arachnoid cyst. Magnetic resonance imaging (MRI) demonstrated a compressive cystic lesion at the level of the L3 vertebra splaying the cauda equina. An L3/L4 laminectomy was performed with marsupialisation of the cyst. Histological examination revealed pseudostratified ciliated columnar epithelium confirming the diagnosis of a bronchogenic cyst, as well as a pleated fibrovascular tissue lined by sparsely spaced small monomorphic arachnoidal cells, indicating an arachnoid cyst. We demonstrate that bronchogenic cysts can be successfully treated with marsupialisation.

Intracranial neurenteric cyst traversing the brainstem

Directory of Open Access Journals (Sweden)

Jasmit Singh

2015-01-01

Full Text Available Neurenteric cysts (NECs, also called enterogenous cysts, are rare benign endodermal lesions of the central nervous system that probably result from separation failure of the notochord and upper gastrointestinal tract. Most frequently they are found in the lower cervical spine or the upper thoracic spine. Intracranial occurrence is rare and mostly confined to infratentorial compartment, in prepontine region [51%]. Other common locations are fourth ventricle and cerebellopontine angle. There are few reports of NEC in medulla or the cerebellum. Because of the rarity of the disease and common radiological findings, they are misinterpreted as arachnoid or simple cysts until the histopathological confirmation, unless suspected preoperatively. We herein report a rare yet interesting case of intracranial NEC traversing across the brainstem.

Supratentorial arachnoid cyst management by cystoperitoneal shunt in a 1-year-old European cat

Directory of Open Access Journals (Sweden)

Mathieu Taroni

2015-07-01

Full Text Available Arachnoid cysts are defined as an accumulation of fluid within the arachnoid membrane. Feline intracranial arachnoid cysts are seldom reported, with only three cases in the veterinary literature. A 1-year-old male neutered European cat with a 24 h history of seizures was presented to the small animal neurology department at Vetagro Sup, Lyon. Magnetic resonance imaging (MRI revealed a large intracranial arachnoid cyst ventral to the brain in the left temporal area. Cystoperitoneal shunt placement resulted in complete resolution of the cyst without recurrence (follow-up MRIs 3 weeks and 21 months after surgery. Anticonvulsant treatment (phenobarbital 2.5 mg/kg q12h was initiated at presentation and gradually stopped after 17 months. Seizures recurred 4 months after ending treatment, and seizure therapy was therefore restarted at the initial dose. We report a case of an intracranial arachnoid cyst in an unusual location not previously described. A cystoperitoneal shunt resolved the cyst without complications. Maintenance anticonvulsant treatment was required to control symptomatic epilepsy.

The superiority of 3D-CISS sequence in displaying the cisternal segment of facial, vestibulocochlear nerves and their abnormal changes

Energy Technology Data Exchange (ETDEWEB)

Liang Changhu, E-mail: tigerlch@163.co [Shandong University, Shandong Medical Imaging Research Institute, CT Room, 324, Jingwu Road, Jinan, Shandong (China); Zhang Bin, E-mail: liangchangbo.student@sina.co [Liao Cheng City People' s Hospital, Dongchang Road, Liaocheng, Shandong (China); Wu Lebin, E-mail: Lebinwu518@163.co [Shandong University, Shandong Medical Imaging Research Institute, CT Room, 324, Jingwu Road, Jinan, Shandong (China); Du Yinglin, E-mail: duyinglinzhuo@sohu.co [Shandong Provincial Center for Disease Control and Prevention, Public Health Institute, 72, Jingshi Road, Jinan, Shandong (China); Wang Ximing, E-mail: wxminmg369@163.co [Shandong University, Shandong Medical Imaging Research Institute, CT Room, 324, Jingwu Road, Jinan, Shandong (China); Liu Cheng, E-mail: cacab2a@126.co [Shandong University, Shandong Medical Imaging Research Institute, CT Room, 324, Jingwu Road, Jinan, Shandong (China); Yu Fuhua, E-mail: changhu1970@163.co [Weifang Medical College, 7166, West Road Baotong Weifang, Shandong (China)

2010-06-15

Objective: To select the best imaging method for clinical otologic patients through evaluating 3D constructive interference of steady state (CISS) image quality in visualizing the facial, vestibulocochlear nerves (CN:VII-VIII) and their abnormal changes. Methods: The CN:VII-VIII as well as inner ear structures in 48 volunteers were examined using 3D-CISS and 3D turbo spin echo (TSE) sequences respectively, and displayed to the full at the reformatted and maximum intensity projection (MIP) images. The nerve identification and image quality were graded for the CN:VII-VIII as well as inner ear structures. Statistical analysis was performed using the Wilcoxin test, p < 0.05 was considered significant. In addition, 8 patients with abnormality in facial or vestibulocochlear nerves were also examined using 3D-CISS sequence. Results: The identification rates for the cisternal segment of facial, vestibulocochlear nerves and corresponding membranous labyrinth were 100%. Abnormal changes of the facial or vestibulocochlear nerves were clearly shown in 8 patients, among them 1 was caused by bilateral acoustic neurinoma, 1 by cholesteatoma at cerebellopontine angle, 1 by arachnoid cyst, 1 by neurovascular adhesion, 4 by neurovascular compression. Conclusion: With 3D-CISS sequence the fine structure of the CN:VII-VIII and corresponding membranous labyrinth can be clearly demonstrated; lesions at the site of cerebellopontine angle can also be found easily.

Cerebral Arachnoid Cysts

Directory of Open Access Journals (Sweden)

Ersin Haciyakupoglu

2016-09-01

Full Text Available Arachnoid cysts can occur through inflammatory, traumatic, chemical irritation, skin tumor and postoperative processes. It is diagnosed and differentiated by magnetic resonance imaging and computerized tomography from other lesions. Its differential diagnosis includes colloid cyst , craniopharyngioma, prosencephaly, holoprosencephaly , epidermoid cyst, hydatid cyst, low grade glial tumors, infarcts and subdural hygroma. Most of them are asymptomatic and diagnosed incidentally. Treatment methods such as simple cyst aspiration , total excision of the cyst, basal cysternostomy, ventricular fenestration, cysto or ventriculoperitoneal shunt can be performed by various endoscopic surgery and craniotomy. [Archives Medical Review Journal 2016; 25(3.000: 259-268

Spinal Extradural Arachnoid Cyst

OpenAIRE

Choi, Seung Won; Seong, Han Yu; Roh, Sung Woo

2013-01-01

Spinal extradural arachnoid cyst (SEAC) is a rare disease and uncommon cause of compressive myelopathy. The etiology remains still unclear. We experienced 2 cases of SEACs and reviewed the cases and previous literatures. A 59-year-old man complained of both leg radiating pain and paresthesia for 4 years. His MRI showed an extradural cyst from T12 to L3 and we performed cyst fenestration and repaired the dural defect with tailored laminectomy. Another 51-year-old female patient visited our cli...

Arachnoid cysts with spontaneous intracystic hemorrhage and associated subdural hematoma: Report of management and follow-up of 2 cases

Directory of Open Access Journals (Sweden)

Mehmet Emin Adin, MD

2018-04-01

Full Text Available Arachnoid cysts are one of the most frequently encountered intracranial space-occupying lesions in daily neurosurgery and neuroradiology practice. Majority of arachnoid cysts, particularly those of smaller sizes, have a benign uneventful lifetime course. Certain symptoms may indicate serious complications related to underlying arachnoid cysts. Hemorrhage is one of the most fearsome complications of arachnoid cysts and almost all reported cases in the literature have undergone surgical correction. In this study, we aimed to present clinical and radiologic follow-up findings in two adult cases of intracranial arachnoid cyst with spontaneous intracystic hemorrhage and associated subdural hematoma, one of which was successfully treated conservatively. In addition, we broadly summarized and discussed pertinent studies in the English literature. Keywords: Arachnoid cyst, Subdural hematoma, Intracystic hemorrhage, Headache

Non-communicating extradural arachnoid cyst: a rare case report with review of literature

Directory of Open Access Journals (Sweden)

Gupta Asheesh Kumar

2018-03-01

Full Text Available Extradural arachnoid cysts in the spine are uncommon causes of spinal cord compression in the paediatric population that are thought to arise from congenital defects in the duramater. In most literatures it is describe that such cysts communicating with the intrathecal subarachnoid space through a small defect in the dura. In this case report we describe a case of a child who presented with spinal cord compression caused by a large spinal extradural arachnoid cyst that did not communicate with the intradural subarachnoid space. An 9 year-old girl presented with progressive lower-extremity weakness, myelopathy, and severe gait ataxia. Magnetic resonance imaging of the spine demonstrated a large extradural arachnoid cyst extending from T4 to T9. The patient underwent a thoracic laminectomy for en bloc resection of the spinal extradural arachnoid cyst. Intra-operatively, the dura was intact and there was no evidence of communication into the intradural subarachnoid space. Postoperatively, the patient’s motor strength and ambulation improved immediately, and no subsequent cerebrospinal fluid leak occurred.

Chronic Subdural Hematoma Associated with Arachnoid Cyst in Young Adults: A Case Report

Directory of Open Access Journals (Sweden)

Jun-Yeen Chan

2008-01-01

Full Text Available Inrracranial arachnoid cysts are believed to be congenital; they can become symptomatic in pediarric patients. Chronic subdural hematomas tend to occur in elderly patients with a history of mild head injury a few months prior to the onset of symptoms. However, these two distinct clinical entities sporadically occur together in relatively young patients. We report a 29-year-old man who presented with headache and dizziness of 2 months' duration. Brain computed tomography revealed a huge chronic subdural hematoma over the left frontoparietal lobe, with an incidental finding of an arachnoid cyst over the left sylvian fissure. In light of a literature review, we discuss arachnoid cysts as a possible risk factor for subdural hematoma, especially in young adults.

Temporo-sylvian arachnoidal cyst and an extreme pneumatization of the cranial sinuses: a case report.

Science.gov (United States)

Zara, Gabriella; Ponza, Isabella; Citton, Valentina; Manara, Renzo

2010-11-01

We present a patient who showed MRI evidence of a giant temporo-sylvian arachnoidal cyst of the left hemisphere and an extreme pneumatization of the sphenoid and frontal sinuses. No sign of mass effect or cerebral atrophy was detected. This patient presented a deficit of memory and control functions, but quality of life was not affected. Surgery was not performed. Arachnoidal cyst and anatomic variants of the sinus region have not a common etiology. This is the first report that describes a giant temporo-sylvian arachnoidal cyst with anatomic variants of the paranasal sinuses. Copyright © 2010 Elsevier B.V. All rights reserved.

An arachnoid cyst presenting as an intramedullary tumour

NARCIS (Netherlands)

Willems, P. W.; van den Bergh, W. M.; Vandertop, W. P.

2000-01-01

A case of thoracic intradural extramedullary arachnoid cyst is presented in which an intramedullary low grade glioma was suspected preoperatively. The cyst was widely fenestrated and postoperatively, the patient experienced considerable improvement in her symptoms. As postoperative MRI studies also

Focal adhesive arachnoiditis of the spinal cord: Imaging diagnosis and surgical resolution

Directory of Open Access Journals (Sweden)

Hiroki Morisako

2010-01-01

Full Text Available Background: Although adhesive arachnoiditis of the spinal cord can cause progressive symptoms associated with syringomyelia or myelomalacia, its surgical resolution based on the imaging diagnosis is not well characterized. This study aims to describe the use of imaging for the diagnosis of focal adhesive arachnoiditis of the spinal cord and its surgical resolution using microsurgical arachnoidolysis. Materials and Methods: Four consecutive patients with symptomatic syringomyelia or myelomalacia caused by focal adhesive arachnoiditis underwent microsurgical arachnoidolysis. Comprehensive imaging evaluation using constructive interference in steady-state (CISS magnetic resonance imaging (MRI or myelographic MR imaging using true fast imaging with steady-state precession (TrueFISP sequences was included before surgery to determine the surgical indication. Results: In all four patients a focal adhesion was identified at the cervical or thoracic level of the spinal cord, a consequence of infection or trauma. Three patients showed modest or minor improvement in neurological function, and one patient was unchanged after surgery. The syringomyelia or myelomalacia resolved after surgery and no recurrence was noted within the follow-up period, which ranged from 5 months to 30 months. Conclusions: MRI diagnosis of focal adhesive arachnoiditis is critical to determine the surgical indication. Microsurgical arachnoidolysis appears to be a straightforward method for stabilizing the progressive symptoms, though the procedure is technically demanding.

Anatomic relationship between arachnoid granulations in the transverse sinus and the termination of the vein of Labbe: an angiographic study

International Nuclear Information System (INIS)

Gailloud, P.; Muster, M.; Khaw, N.; Martin, J.B.; Murphy, K.J.; Ruefenacht, D.A.; Fasel, J.H.D.

2001-01-01

We studied the anatomic relationship between arachnoid granulations in the transverse sinus and the termination of the vein of Labbe in 57 consecutive angiograms. Patients with pathology in intracranial venous structures or with inadequate image quality of the venous system were excluded. Arachnoid granulations were found in 12 of the 57 patients (21.1 %), always at the junction of the vein of Labbe and the transverse sinus; the vein of Labbe was present in 55 patients (96.5 %), most often without associated arachnoid granulations; the latter, however, were not observed in the absence of a vein of Labbe. This study confirms the close, constant anatomic relationship between arachnoid granulations in the transverse sinus and the termination of the vein of Labbe. This observation may help to differentiate arachnoid granulations from pathologic conditions involving the transverse sinus such as dural sinus thrombosis. The constant character of this relationship suggests a developmental role of afferent veins in the formation of arachnoid granulations. (orig.)

[Constitutional syndrome as a presentation of a cerebellopontine meningioma].

Science.gov (United States)

Ruiz-Serrato, A; Mata-Palma, A; Olmedo-Llanes, J; García-Ordóñez, M A

2014-03-01

Meningiomas are basically benign tumours arising in the meninges and account for 15-25% of intracranial tumours in adults. It is clinically signs are due to compression of the neighbouring structures, with the main symptoms being migraine, behavioural changes, and neurological deficits. We present a case where constitutional syndrome was the first and principal manifestation of an intracranial cerebellopontine meningioma. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

Imaging of thoracic and lumbar spinal extradural arachnoid cysts: report of two cases

International Nuclear Information System (INIS)

Rimmelin, A.; Clouet, P.L.; Salatino, S.; Kehrli, P.; Maitrot, D.; Stephan, M.; Dietemann, J.L.

1997-01-01

Extradural arachnoid cysts are uncommon expanding lesions in the spinal canal which may communicate with the subarachnoid space. Usually in the lower thoracic spine, they may cause symptoms by compressing the spinal cord or nerve roots. We report cases of thoracic and lumbar arachnoid cysts studied by cystography, myelography, CT and MRI. These techniques showed extradural cystic lesions containing cerebrospinal fluid, with variable communication with the subarachnoid space, causing anterior displacement and flattening of the spinal cord. (orig.)

A New Classification for Pathologies of Spinal Meninges-Part 2: Primary and Secondary Intradural Arachnoid Cysts.

Science.gov (United States)

Klekamp, Jörg

2017-08-01

Spinal intradural arachnoid cysts are rare causes of radiculopathy or myelopathy. Treatment options include resection, fenestration, or cyst drainage. To classify intradural spinal arachnoid cysts and present results of their treatment. Among 1519 patients with spinal space occupying lesions, 130 patients demonstrated intradural arachnoid cysts. Neuroradiological and surgical features were reviewed and clinical data analyzed. Twenty-one patients presented arachnoid cysts as a result of an inflammatory leptomeningeal reaction related to meningitis, subarachnoid hemorrhage, intrathecal injections, intradural surgery, or trauma, ie, secondary cysts. For the remaining 109 patients, no such history could be elucidated, ie, primary cysts. Forty-six percent of primary and 86% of secondary cysts were associated with syringomyelia. Patients presented after an average history of 53 ± 88 months. There were 122 thoracic and 7 lumbar cysts plus 1 cervical cyst. Fifty-nine patients with primary and 15 patients with secondary cysts underwent laminotomies with complete or partial cyst resection and duraplasty. Mean follow-up was 57 ± 52 months. In the first postoperative year, profound improvements for primary cysts were noted, in contrast to marginal changes for secondary cysts. Progression-free survival for 10 years following surgery was determined as 83% for primary compared to 15% for secondary cysts. Despite differences in clinical presentation, progression-free survival was almost identical for patients with or without syringomyelia. Complete or partial resection leads to favorable short- and long-term results for primary arachnoid cysts. For secondary cysts, surgery can only provide clinical stabilization for a limited time due to the often extensive arachnoiditis. Copyright © 2017 by the Congress of Neurological Surgeons

Contrast-enhanced MRI of intrasellar arachnoid cysts: relationship between the pituitary gland and cyst

International Nuclear Information System (INIS)

Nomura, M.; Kanazawa Univ. School of Medicine; Tachibana, O.; Hasegawa, M.; Kohda, Y.; Nakada, M.; Yamashima, T.; Yamashita, J.; Suzuki, M.

1996-01-01

We recently encountered two large intrasellar arachnoid cysts extending to the suprasellar region. The intensity of the cyst contents was identical to that of the cerebrospinal fluid on both T1- and T2-weighted MRI. On contrast-enhanced MRI, the pituitary gland was compressed posteroinferiorly and flattened in the sella turcica. In this report of rare intrasellar arachnoid cysts the discussion is focused on dislocation of the pituitary gland. (orig.)

Post-traumatic arachnoiditis: an unusual cause of Brown-Sequard syndrome

International Nuclear Information System (INIS)

Ramli, N.; Merican, A.M.; Lim, A.; Kumar, G.

2001-01-01

Brown-Sequard syndrome (BSS) is a unilateral cord injury characterised by an ipsilateral motor deficit with contralateral pain and temperature hypoaesthesia. Although there are a variety of causes, the majority of cases are generally of neoplastic origin or are traumatic in origin. We describe a rare cause of Brown-Sequard syndrome as a result of post-traumatic arachnoiditis. Magnetic resonance imaging with the use of thin-slice high-resolution constructive interference in steady state (CISS) and T2-weighted spin-echo sequence were used to demonstrate the cause and appearance of the lesion in the spinal canal and was useful in the assessment and management of the patient. This case illustrates the usefulness of the CISS sequence in MRI for elucidating arachnoiditis. (orig.)

A patient with myasthenia gravis and a large arachnoid cyst - report of a case.

Science.gov (United States)

Bucuk, Mira; Gasparovic, Iva; Sonnenschein, Ivan; Perkovic, Olivio

2017-05-01

Myasthenia gravis is a chronic autoimmune disease characterized by weakening of voluntary muscles during the day and a marked restitution of function during the night and after rest. The symptoms may worsen over days or weeks, sometimes even in a few hours, and are usually well controlled by appropriate therapy. Arachnoid cysts are congenital or acquired deformities of the arachnoid membrane and are usually too small to cause distinct clinical symptomatology. We describe a case of a 76-year-old myasthenia gravis patient with an arachnoid cyst. To the best of our knowledge this is the first reported case of these two comorbidities together.

Treatment and diagnosis of middle fossa arachnoid cyst. Ventriculofiberscopy and cine-MRI

Energy Technology Data Exchange (ETDEWEB)

Kamikawa, Shuji; Kuwamura, Keiichi [Hyogo Prefectural Awaji Hospital, Sumoto (Japan); Tamaki, Norihiko

1998-07-01

The treatment of intracranial arachnoid cysts is controversial regarding its surgical indication and operative procedures. Conventional surgical approaches such as fenestration, membranectomy, and shunting operation are invasive. Also CT cisternography and/or RI cisternography are invasive, when it has been performed to evaluate the possible CSF communications between the arachnoid cyst and subarachnoid space. Between July 1994 and February 1997, 10 patients with intracranial middle fossa arachnoid cysts were treated with a newly developed ventriculofiberscope which is characterized by splendid mechanical flexibility and high resolution. The cine-MRI, which is a non-invasive diagnostic tool, is used to evaluate the CSF circulation around the cyst fenestration. The patients` ages ranged from 4 months to 10 years, with a mean of 4.46 years. The cyst locations were left middle fossa (9), and right (1). Eight patients presented with macrocrania, 4 with developmental delay, three with seizure, two with headache, and one with subdural hematoma. The patients were preoperatively evaluated by means of MRI and cine-MR images. In all patients ventriculofiberscopic procedures including cyst fenestration, membranous dissection, cyst puncture and shriveling were successfully performed. Postoperative MR and cine-MR studies have shown reduction of the cyst size and appropriate CSF circulation. Neuroendoscopic procedures seem to be the first choice for children with arachnoid cysts and the ventriculofiberscope proved to be very useful not only for cyst fenestration but also for cyst dissection. In addition, the non-invasive cine-MR studies are useful for long follow-up at OPD. (author)

Fruit diet of Alouatta guariba and Brachyteles arachnoides in Southeastern Brazil: comparison of fruit type, color, and seed size.

Science.gov (United States)

Martins, Milene Moura

2008-01-01

Fruit is an important food resource for neotropical primates. In this study I compare the fruit diet of sympatric brown howlers (Alouatta guariba) and southern muriquis (Brachyteles arachnoides). Feeding behavior was studied over 12 months and fruit species consumed were identified and assigned to the categories fruit type, fruit color, and seed size. Observed-fruit feeding records were compared with expected records determined from local availability of the fruit of the tree species. I also determined dietary overlap. Fruit consumption occupied 8 and 12% of the feeding time of A. guariba and B. arachnoides, respectively. Fruit from eight tree species were consumed by the former and fruit from twenty-two species by the latter. Patterns of fruit selection of A. guariba and B. arachnoides varied widely. Although howlers and muriquis converge behaviorally by selecting fruit with common attributes (fleshy/unprotected, violet and brown/black-colored), unlike A. guariba, B. arachnoides fed on immature seeds of fleshy/protected and dry fruit. Large seeds were ingested, and defecated intact, by B. arachnoides only. There was little overlap of fruit diet even within categories that had been selected by both, suggesting that dietary divergence is occurring at the interspecific level. Different resource exploitation probably mediates the coexistence of A. guariba and B. arachnoides in low diversity, semideciduous forests, where the environment imposes narrow limits on primate food choices.

CT and MRI findings of a spinal arachnoid cyst

International Nuclear Information System (INIS)

Takahashi, Ryosuke; Kusaka, Hirofumi; Sadashima, Hiromichi

1986-01-01

A 39-year-old woman developed progressive difficulty in walking and urination over one year and 9 months. Her past history included a hystero-oophorectomy because of ''infection;'' the operation had been done under lumbar anesthesia. At the time of admission to our hospital, her legs were markedly spastic, with increased knee and ankle jerks as well as bilateral Babinski signs. Sensation to pain was slightly decreased bilaterally at and below Th4. Myelography through a suboccipital tap and CT myelography demonstrated a block of the CSF space at Th6. The spinal cord was displaced and became thin at and below Th1, secondary to an enlarged CSF space. Horizontal MRI demonstrated similar findings; however, sagittal MRI showed that the cord had been displaced and had collapsed; in addition, an abnormally enlarged CSF space indicated a subdural arachnoid cyst. MRI has thus been shown to be a very useful tool in the diagnosis of a spinal arachnoid cyst as well as other spinal-cord diseases. (author)

Cauda equina syndrome after spinal anaesthesia in a patient with asymptomatic tubercular arachnoiditis

Directory of Open Access Journals (Sweden)

Divya Sethi

2011-01-01

Full Text Available A 14-year-old boy underwent emergency debridement surgery of right foot under spinal anaesthesia. Four hours after the surgery, the patient developed symptoms of cauda equina syndrome (CES. Postoperative magnetic resonance imaging of the patient′s spine suggested underlying tubercular arachnoiditis. The boy was started on intravenous methylprednisolone and antitubercular therapy. He responded to the therapy and recovered completely in 2 weeks without any residual neurological deficits. We suggest that underlying pathological changes in the subarachnoid space due to tubercular arachnoiditis contributed to maldistribution of the local anaesthetic drug leading to CES.

Computer tomographic detection of an intraspinal arachnoidal cyst

Energy Technology Data Exchange (ETDEWEB)

Kuckein, D; Walter, K; Paal, G

1981-03-01

A 46 year old female patient who after 3-4 weeks of influenza suffered from strong headaches, vomiting and rotatory vertigo was subjected to a myelograph and then to a computerized tomographic investigation due to suspect cerebrospinal fluid. The computerized tomography is better than the myelography in diagnosing intraspinal arachnoidal cysts, however this should be preceded by most accurate possible segment location.

Characterization of cytoskeletal and junctional proteins expressed by cells cultured from human arachnoid granulation tissue

Directory of Open Access Journals (Sweden)

Mehta Bhavya C

2005-10-01

Full Text Available Abstract Background The arachnoid granulations (AGs are projections of the arachnoid membrane into the dural venous sinuses. They function, along with the extracranial lymphatics, to circulate the cerebrospinal fluid (CSF to the systemic venous circulation. Disruption of normal CSF dynamics may result in increased intracranial pressures causing many problems including headaches and visual loss, as in idiopathic intracranial hypertension and hydrocephalus. To study the role of AGs in CSF egress, we have grown cells from human AG tissue in vitro and have characterized their expression of those cytoskeletal and junctional proteins that may function in the regulation of CSF outflow. Methods Human AG tissue was obtained at autopsy, and explanted to cell culture dishes coated with fibronectin. Typically, cells migrated from the explanted tissue after 7–10 days in vitro. Second or third passage cells were seeded onto fibronectin-coated coverslips at confluent densities and grown to confluency for 7–10 days. Arachnoidal cells were tested using immunocytochemical methods for the expression of several common cytoskeletal and junctional proteins. Second and third passage cultures were also labeled with the common endothelial markers CD-31 or VE-cadherin (CD144 and their expression was quantified using flow cytometry analysis. Results Confluent cultures of arachnoidal cells expressed the intermediate filament protein vimentin. Cytokeratin intermediate filaments were expressed variably in a subpopulation of cells. The cultures also expressed the junctional proteins connexin43, desmoplakin 1 and 2, E-cadherin, and zonula occludens-1. Flow cytometry analysis indicated that second and third passage cultures failed to express the endothelial cell markers CD31 or VE-cadherin in significant quantities, thereby showing that these cultures did not consist of endothelial cells from the venous sinus wall. Conclusion To our knowledge, this is the first report of

Microsurgery Simulator of Cerebral Aneurysm Clipping with Interactive Cerebral Deformation Featuring a Virtual Arachnoid.

Science.gov (United States)

Shono, Naoyuki; Kin, Taichi; Nomura, Seiji; Miyawaki, Satoru; Saito, Toki; Imai, Hideaki; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito

2018-05-01

A virtual reality simulator for aneurysmal clipping surgery is an attractive research target for neurosurgeons. Brain deformation is one of the most important functionalities necessary for an accurate clipping simulator and is vastly affected by the status of the supporting tissue, such as the arachnoid membrane. However, no virtual reality simulator implementing the supporting tissue of the brain has yet been developed. To develop a virtual reality clipping simulator possessing interactive brain deforming capability closely dependent on arachnoid dissection and apply it to clinical cases. Three-dimensional computer graphics models of cerebral tissue and surrounding structures were extracted from medical images. We developed a new method for modifiable cerebral tissue complex deformation by incorporating a nonmedical image-derived virtual arachnoid/trabecula in a process called multitissue integrated interactive deformation (MTIID). MTIID made it possible for cerebral tissue complexes to selectively deform at the site of dissection. Simulations for 8 cases of actual clipping surgery were performed before surgery and evaluated for their usefulness in surgical approach planning. Preoperatively, each operative field was precisely reproduced and visualized with the virtual brain retraction defined by users. The clear visualization of the optimal approach to treating the aneurysm via an appropriate arachnoid incision was possible with MTIID. A virtual clipping simulator mainly focusing on supporting tissues and less on physical properties seemed to be useful in the surgical simulation of cerebral aneurysm clipping. To our knowledge, this article is the first to report brain deformation based on supporting tissues.

Computer tomographic detection of an intraspinal arachnoidal cyst

International Nuclear Information System (INIS)

Kuckein, D.; Walter, K.; Paal, G.; Staedtisches Krankenhaus Harlaching, Muenchen

1981-01-01

A 46 year old female patient who after 3-4 weeks of influenza suffered from strong headaches, vomiting and rotatory vertigo was subjected to a myelograph and then to a computerized tomographic investigation due to suspect cerebrospinal fluid. The computerized tomography is better than the myelography in diagnosing intraspinal arachnoidal cysts, however this should be preceded by most accurate possible segment location. (MG) [de

Study of the clinical features and radiological findings for thoracic communicating arachnoid cysts

International Nuclear Information System (INIS)

Oda, Masashi; Hanakita, Junya; Suwa, Hideyuki

2001-01-01

We analyzed retrospectively, the usefulness of the radiological examinations for 15 cases of communicating arachnoid cysts in thoracic lesions experienced by our department over the last 12 years. Severn men and eight women (age range 32-71 years, mean age 53.8 years) were analyzed. Their symptoms on admission were sensory disturbance of the legs (13 cases), leg weakness (4 cases), back pain (4 cases), and truncal abnormal sensations (2 cases), etc. We performed myelography in 12 patients, and an additional 5 patients were diagnosed by this examination. CT-myelography showed deformity of the spinal cord, deviation of the spinal cord and enlargement of the subarachnoid space in all 12 patients. The axial view in 1.0 T weighted MRI showed the same findings as CT-myelography. However, the cine 1.0 T weighted MRI seemed to be insufficient to detect any spinal arachnoid cysts. As the results of their operations, 13 patients improved, 2 patients remained unchanged, and no cases become worse. The clinical and radiological diagnosis for communicating arachnoid cysts is not easy. Neurological examinations and radiological examinations with detailed readings are essential to obtain a correct diagnosis, when considering the possibility of the disease. (author)

Thoracic intradural arachnoid cyst: Possible pitfalls with myelo-CT and MR

International Nuclear Information System (INIS)

Dietemann, J.L.; Filippi de la Palavesa, M.M.; Kastler, B.; Warter, J.M.; Buchheit, F.

1991-01-01

A thoracic intradural arachnoid cyst presenting as an intradural extramedullary mass highly suggestive of psammoma on myelogram and myelo-CT is reported in a 34-year-old female. High densities of the cyst were related to collection of contrast media within the cyst. However MR examination of the thoracic spinal cord including sagittal T1 (without and with contrast) and T2 studies failed to demonstrate the mass. Lack of MR changes were related on one hand to the small size of the cyst and to the absence of mass effect on the spinal cord, and on the other hand to a CSF-like signal of the contents of the cyst. Only combination of myelography, myelo-CT and MR allows precise diagnosis of small intradual arachnoid cysts; however MR is the method of choice for evaluation of large intradural subarachnoid cysts. (orig.)

Lianas as a food resource for brown howlers (Alouatta guariba and southern muriquis (Brachyteles arachnoides in a forest fragment

Directory of Open Access Journals (Sweden)

M. M. Martins

2009-01-01

Full Text Available Lianas as a food resource for brown howlers (Alouatta guariba and southern muriquis (Brachyteles arachnoides in a forest fragment.— Lianas, woody vines, are abundant and diverse in tropical forests, but their relative contribution as a source of food for herbivores has been neglected. I compared feeding rates on lianas and trees of two sympatric primates, A. guariba and B. arachnoides, in Southeastern Brazil. Availability of liana foods was gathered in parallel with primate behavioral data collection. Liana represented 33.9% and 27.3% of food sources for A. guariba and B. arachnoides, respectively. Foods coming from trees, rather than from lianas, were significantly more consumed by B. arachnoides. However, both species took advantage of the continuously renewable and ephemeral food resources provided by liana. Availability of liana flowers correlated positively with A. guariba feeding proportions. The nutritional supply provided by lianas is apparently beneficial, or at least unharmful, but experiments comparing primate choices in forests with different liana abundances will help to shed light on their possible negative effect on communities.

Benign occipital unicameral bone cyst causing lower cranial nerve palsies complicated by iophendylate arachnoiditis

Science.gov (United States)

Bradley, W. G.; Kalbag, R. M.; Ramani, P. S.; Tomlinson, B. E.

1974-01-01

A 20 year old girl presented with a history of neck and occipital pain for six weeks, which was found to be due to a unicameral bone cyst of the left occipital condylar region. The differential diagnosis of bone cysts in the skull is discussed. Six months after the operation, the patient again presented with backache due to adhesive arachnoiditis. The latter was believed to have arisen as a result of a combination of spinal infective meningitis and intrathecal ethyl iodophenyl undecylate (iophendylate, Myodil, Pantopaque). The nature of meningeal reactions to iophendylate and the part played by intrathecal corticosteroids in relieving the arachnoiditis in the present case are discussed. Images

Aneurysm, arachnoiditis and intrathecal Au (gold)

International Nuclear Information System (INIS)

Pence, D.M.; Kim, T.H.; Levitt, S.H.

1990-01-01

This report is a 20-year follow-up of 14 patients treated with external beam craniospinal irradiation and intrathecal gold (10-45 mCi) for medulloblastoma. Six of the patients died within 2 years of treatment from persistent disease. No patients are alive without complications. Six of eight surviving patients developed arachnoiditis and cauda equina syndrome within 5 to 10 years of treatment. Seven of eight survivors developed aneurysms and/or cerebrovascular accidents 9 to 20 years after treatment. Four of the cerebrovascular events were fatal. Intrathecal gold pools in the basal cisterns and cauda equina delivering an extremely inhomogeneous dose throughout the neuroaxis. Its use is discouraged

Supraorbital Keyhole Microsurgical Fenestration of Symptomatic Temporal Arachnoid Cysts in Children: Advantages and Limitations.

Science.gov (United States)

Elkheshin, Sherif; Soliman, Ahmed

2017-01-01

To investigate the impact of endoscope-assisted microsurgical fenestration on temporal arachnoid cysts, and to determine the advantages and limitations of the technique. Twenty-five children with symptomatic temporal arachnoid cysts were operated via eyebrow supraorbital keyhole microsurgical fenestration targeting the medial cyst wall. Preoperative magnetic resonance imaging (MRI) of the brain was done for all patients. Preoperative clinical presentation of the patients included headache (80%), nausea & vomiting (64%), drug resistant epilepsy (52%), macrocephaly (12%) papilledema (28%), motor weakness in the form of right-sided hemiparesis (12%) and cranial nerve palsy. Postoperative complete subsidence of headache was noted in 50%, while 20% remained unchanged. Drug resistant epilepsy improved in 69% of the patients. Postoperative MRI showed initial decrease in cyst volume as early as 3 months, only in a range of 5-12% volume reduction, and the late follow-up done at 6 and 18 months continued to show further reduction reported to be significant (p CSF) collection was the most common complication (20%). Only 1 patient experienced CSF leak mandating cysto-peritoneal shunting. Conclusıon: Eyebrow supraorbital keyhole microsurgical fenestration for temporal arachnoid cysts can be performed with a fairly low risk of complications and yields a favorable improvement in clinical and neuroimaging outcomes.

De Novo Intraneural Arachnoid Cyst Presenting with Complete Third Nerve Palsy: Case Report and Literature Review.

Science.gov (United States)

Brewington, Danielle; Petrov, Dmitriy; Whitmore, Robert; Liu, Grant; Wolf, Ronald; Zager, Eric L

2017-02-01

Intraneural arachnoid cyst is an extremely rare etiology of isolated cranial nerve palsy. Although seldom encountered in clinical practice, this pathology is amenable to surgical intervention. Correct identification and treatment of the cyst are required to prevent permanent nerve damage and potentially reverse the deficits. We describe a rare case of isolated third nerve palsy caused by an intraneural arachnoid cyst. A 49-year-old woman with a recent history of headaches experienced acute onset of painless left-sided third nerve palsy. According to hospital records ptosis, mydriasis, absence of adduction, elevation, and intorsion were noted in the left eye. Computed tomography and magnetic resonance imaging studies showed an extra-axial, 1-cm lesion along the left paraclinoid region, causing mild indentation on the uncus. There was dense fluid layering dependently concerning for hemorrhage, but no evidence of aneurysms. A pterional craniotomy was performed, revealing a completely intraneural arachnoid cyst in the third nerve. The cyst was successfully fenestrated. At 7-month follow-up, the left eye had recovered intact intorsion and some adduction, but the left pupil remained dilated and nonreactive. There was still no elevation and no afferent pupillary defect. Double vision persisted with partial improvement in the ptosis, opening up to more than 75% early in the day. To our knowledge, this is the first report of an intraneural arachnoid cyst causing isolated third nerve palsy. This rare pathology proves to be both a diagnostic and therapeutic challenge. Copyright © 2016 Elsevier Inc. All rights reserved.

Anatomic Dissection of Arachnoid Membranes Encircling the Pituitary Stalk on Fresh, Non-Formalin-Fixed Specimens: Anatomoradiologic Correlations and Clinical Applications in Craniopharyngioma Surgery.

Science.gov (United States)

Ciappetta, Pasqualino; Pescatori, Lorenzo

2017-12-01

The anatomy of the arachnoid membranes and cisternal spaces around the pituitary stalk has not been yet exhaustively described and understood. In this study, we performed a detailed anatomic study on fresh, non-formalin-fixed cadavers of the arachnoid membranes encircling the pituitary stalk and correlate our anatomic findings with magnetic resonance imaging (MRI). Ten fresh, non-formalin-fixed, non-silicon-injected adult cadaveric heads were analyzed in this study. The membrane and cisterns that were studied for our study were as follows: 1) the diaphragma sellae and its dural components; 2) the basal arachnoid membrane; 3) the Liliequist membrane with its diencephalic and mesencephalic portion; 4) the medial carotid membrane; 5) the chiasmatic cistern; and 6) the pituitary stalk. MRI examinations of the sellar region were performed in 15 healthy volunteers (9 men, mean age 40 years; and 6 women mean age, 37 years) to visualize the arachnoid membrane encircling the pituitary stalk. MRI examinations were performed with a 3-T unit. A 3-dimensional constructive interference in steady state pulse magnetic resonance sequence was used. All the membranes examined were visualized clearly in all the dissections performed. Their 3-dimensional organization around the pituitary stalk was clarified and confirmed by MRI. Our study gives a detailed description of the pituitary stalk arachnoid sheets on fresh, non-formalin-fixed cadavers. This technique allowed us to clearly identify a funnel-shaped arachnoid collar encircling the pituitary stalk and delimiting a distinct cisternal space belonging to the stalk itself. Copyright © 2017 Elsevier Inc. All rights reserved.

Tridimensional architecture of the collagen element in the arachnoid granulations in humans: a study on scanning electron microscopy

Directory of Open Access Journals (Sweden)

Conegero Celso Ivan

2003-01-01

Full Text Available The arachnoid granulations of adult individual of both sexes were studied through scanning electron microscopy. The dura mater and arachnoid meninges of individuals were collected at the Service of Death Verification of São Paulo - USP and fixed in Karnovsky solution. After this period the material was prepared for analysis in electron microscope. Our results demonstrated that the arachnoid granulations are formed by a pedicle, body and apex, being surrounded by a capsule of connective tissue, which in turn is composed of, basically, bundles of collagen fibers that line pores of different shapes and sizes. The smaller pores are lined by tiny bundles and are located at the apical region of the granulation and the larger are lined by thicker bundles and are located at the lateral regions. In the body we verified that the bundles of collagen fibers compose a fibrous meshwork and in some regions these bundles have circular orientation, forming pores similar to those found at the region of the capsule.

Spinal Arachnoiditis as a Complication of Cryptococcal Meningoencephalitis in Non-HIV Previously Healthy Adults

Science.gov (United States)

Komori, Mika; Kosa, Peter; Khan, Omar; Hammoud, Dima A.; Rosen, Lindsey B.; Browne, Sarah K.; Lin, Yen-Chih; Romm, Elena; Ramaprasad, Charu; Fries, Bettina C.; Bennett, John E.; Bielekova, Bibiana; Williamson, Peter R.

2017-01-01

Background. Cryptococcus can cause meningoencephalitis (CM) among previously healthy non-HIV adults. Spinal arachnoiditis is under-recognized, since diagnosis is difficult with concomitant central nervous system (CNS) pathology. Methods. We describe 6 cases of spinal arachnoiditis among 26 consecutively recruited CM patients with normal CD4 counts who achieved microbiologic control. We performed detailed neurological exams, cerebrospinal fluid (CSF) immunophenotyping and biomarker analysis before and after adjunctive immunomodulatory intervention with high dose pulse corticosteroids, affording causal inference into pathophysiology. Results. All 6 exhibited severe lower motor neuron involvement in addition to cognitive changes and gait disturbances from meningoencephalitis. Spinal involvement was associated with asymmetric weakness and urinary retention. Diagnostic specificity was improved by MRI imaging which demonstrated lumbar spinal nerve root enhancement and clumping or lesions. Despite negative fungal cultures, CSF inflammatory biomarkers, sCD27 and sCD21, as well as the neuronal damage biomarker, neurofilament light chain (NFL), were elevated compared to healthy donor (HD) controls. Elevations in these biomarkers were associated with clinical symptoms and showed improvement with adjunctive high dose pulse corticosteroids. Conclusions. These data suggest that a post-infectious spinal arachnoiditis is an important complication of CM in previously healthy individuals, requiring heightened clinician awareness. Despite microbiological control, this syndrome causes significant pathology likely due to increased inflammation and may be amenable to suppressive therapeutics. PMID:28011613

Ventriculoscopic surgery for arachnoid cysts in the lateral ventricle: a comparative study of 21 consecutive cases

Science.gov (United States)

Shou, Xuefei; Zhao, Yao; Li, Shiqi; Wang, Yongfei

2015-01-01

Objective: To evaluate neuronavigation-guided ventriculoscopic technique in the treatment of arachnoid cysts in the lateral ventricle. Methods: Between January 2008 to November 2011, twenty-one neuronavigationguided ventriculoscopic surgery were performed for the treatment of symptomatic arachnoid cysts in 21 patients (14 male and 7 female patients, mean age 24.1 years [ranged 1.5-61 years]) Clinical presentations varied from headache, vomiting, hemiparesis and seizure. The trajectory of ventriculoscopy was dynamically monitored and guided in real time by neuronavigation system. Cysts fenestrations were performed in fourteen cases, and cysts resection in seven cases, respectively. All patients were prospectively had a regular follow-up. Results: After operation, all patients achieved symptom resolution without surgical mortality and morbidity. Aseptic meningitis was noted in four cases with cyst resection, and all recovered quickly without advanced treatments. However, a later ependymal adhesion, occurred in one case during follow-up period. Conclusion: The combination of ventriculoscopy and neuronavigation is an accurate, effective and safe approach for the treatment of the patients with arachnoid cysts in the lateral ventricle, especially, for overcoming the topographic variation caused by intraventricular pathologies. Cystoventriculostomy is the best choice. PMID:26885002

Lianas as a food resource for brown howlers (Alouatta guariba) and southern muriquis (Brachyteles arachnoides) in a forest fragment

OpenAIRE

M. M. Martins

2009-01-01

Lianas as a food resource for brown howlers (Alouatta guariba) and southern muriquis (Brachyteles arachnoides) in a forest fragment.— Lianas, woody vines, are abundant and diverse in tropical forests, but their relative contribution as a source of food for herbivores has been neglected. I compared feeding rates on lianas and trees of two sympatric primates, A. guariba and B. arachnoides, in Southeastern Brazil. Availability of liana foods was gathered in parallel with primate behavioral data ...

Malformação da transição crânio-vertebral como causa de síndrome do ângulo ponto-cerebelar: relato de dois casos Cerebello-pontine angle syndrome associated with cranio-vertebral malformation: report of two cases

Directory of Open Access Journals (Sweden)

Amauri Batista da Silva

1972-03-01

Full Text Available Os autores relatam dois casos de síndrome do ângulo ponto-cerebelar nos quais não havia neoplasia nessa região. Ambos os pacientes apresentavam uma associação de impressão basilar com síndrome de Arnold-Chiari. Após cirurgia descompressiva de fossa posterior os casos evoluiram favoravelmente com a diminuição progressiva dos sintomas neurológicos, restando apenas, no segundo paciente, certo grau de paralisia e de espasmo facial, à direita. São feitas considerações em tôrno das causas mais freqüentes da síndrome do ângulo ponto-cerebelar, bem como acêrca dos quadros clínicos mais usualmente encontrados em doentes que apresentam malformações da transição crânio-vertebral. Finalmente, os autores tecem breves considerações a respeito do possível mecanismo lesionai do VIII, do V e do VII nervos cranianos nos dois casos relatados.Two cases of cerebelo-pontine angle syndrome associated with basilar impression and Arnold-Chiari malformation are reported. In both cases neuroradiological studies and surgical exploration failled to demonstrate any space occupying lesion. After surgery the patients progressively recovered disapearing the neurological symptoms except for a slaight hemifacial spasm that remained in case 2. Clinical signs present in cerebello-pontine angle lesions and the occipito-cervical malformations are discussed. A possible mechanism to explain the association of both conditions is discussed.

Pile driving into the skull and suspending the bridging veins? An undescribed role of arachnoid granulations.

Science.gov (United States)

Tsutsumi, Satoshi; Ono, Hideo; Yasumoto, Yukimasa

2017-05-01

Arachnoid granulations (AGs) occasionally appear to protrude into the calvarial convexity, lying close to the bridging veins (BVs). This study aims to characterize such AGs and BVs using magnetic resonance imaging (MRI). Ninety-five patients were enrolled in this study. Initially, stepwise frontal craniotomy was performed in an injected cadaver head. Next, examinations with contrast MRI were performed involving the whole cranial vault. In cadaveric dissection, the AGs located in the parasagittal regions appeared as outward protrusions through the dura mater and in contact with the diploic veins. Forming tent-shaped sleeves, these AGs and the continuous arachnoid membranes suspended the BVs coursing just below. A total of 237 AGs were identified on contrast MRI that protruded into the skull, lying close to the BVs. Among them, 78 % were located in parasagittal regions as AG-BV pairs. These pairs were most frequently found in the middle third of the calvarial hemisphere, followed by the anterior and posterior thirds. In 34 %, the BV segments were lodged in the AGs. Some AGs located in the parasagittal regions and cerebral convexity pass through the dura mater and pile drive into the skull, which contribute to forming hanging-type arachnoid sleeves suspending the BVs. These structures may underpin the predisposition of BVs to injury following mechanical impacts.

Language localization in cases of left temporal lobe arachnoid cyst : Evidence against interhemispheric reorganization

NARCIS (Netherlands)

Stowe, LA; Go, KG; Pruim, J; den Dunnen, W; Meiners, LC; Paans, AMJ

2000-01-01

We investigated whether left-hemisphere arachnoid cysts lead to reorganization of the language function using PET. A group analysis demonstrated that patients showed no more right-hemisphere activation than a matched control group. Several patients had clear language localizations in the left

The rising root sign: the magnetic resonance appearances of post-operative spinal subdural extra-arachnoid collections

Energy Technology Data Exchange (ETDEWEB)

Bharath, A.; Uhiara, O.; Botchu, Rajesh; Davies, A.M.; James, S.L. [The Royal Orthopedic Hospital, Department of Musculoskeletal Radiology, Birmingham (United Kingdom)

2017-09-15

We present a case series of symptomatic post-operative spinal subdural extra-arachnoid collections that displace the cauda equina roots anteriorly. This is described as the ''rising root sign''. (orig.)

Evaluation of the Communication Between Arachnoid Cysts and Neighboring Cerebrospinal Fluid Spaces by T2W 3D-SPACE With Variant Flip-Angle Technique at 3 T.

Science.gov (United States)

Algin, Oktay

2018-05-21

Phase-contrast cine magnetic resonance imaging (PC-MRI) is a widely used technique for determination of possible communication of arachnoid cysts (ACs). Three-dimensional (3D) sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) technique is a relatively new method for 3D isotropic scanning of the entire cranium within a short time. In this research, the usage of the 3D-SPACE technique in differentiation of communicating or noncommunicating type ACs was evaluated. Thirty-five ACs in 34 patients were retrospectively examined. The 3D-SPACE, PC-MRI, and contrast material-enhanced cisternography (if present) images of the patients were analyzed. Each cyst was described according to cyst size/location, third ventricle diameter, Evans index, and presence of hydrocephalus. Communication was defined as absent (score 0), suspected (score 1), or present (score 2) on each sequence. Results of PC-MRI or cisternography (if available) examinations were used as criterion standard techniques to categorize all cysts as communicating or noncommunicating type. The results of 3D-SPACE were compared with criterion standard techniques. The comparisons between groups were performed using Mann-Whitney and Fisher exact tests. For demonstration of communication status of the cysts, criterion standard test results and 3D-SPACE findings were almost in perfect harmony (κ[95% confidence interval: 0.94]; P SPACE findings correlated with other final results at a rate of 97%. There is a positive correlation with third ventricular diameters and Evans index for all patients (r = 0.77, P SPACE technique is an easy, useful, and noninvasive alternative for the evaluation of morphology, topographical relationships, and communication status of ACs.

Clinical Application of 3D-CISS MRI Sequences for Diagnosis and Surgical Planning of Spinal Arachnoid Diverticula and Adhesions in Dogs.

Science.gov (United States)

Tauro, Anna; Jovanovik, Jelena; Driver, Colin John; Rusbridge, Clare

2018-02-01

 Abnormalities within the spinal arachnoid space are often treated surgically, but they can be challenging to detect with conventional magnetic resonance imaging (MRI) sequences. 3D-CISS sequences are considered superior in evaluating structures surrounded by cerebrospinal fluid (CSF) due to the high signal-to-noise ratio, high contrast-to-noise ratio and intrinsic insensitivity to motion with minimal signal loss due to CSF pulsations. Our objective was to describe findings and advantages in adding 3D-CISS sequences to routine MRI in patients affected by spinal arachnoid diverticula (SAD) or arachnoid adhesions.  This article is a retrospective review of medical records of 19 dogs admitted at Fitzpatrick Referrals between 2013 and 2017 that were diagnosed with SAD and confirmed surgically. Inclusion criterions were the presence of clinical signs compatible with compressive myelopathy and an MRI diagnosis, which included the 3D-CISS sequence. Our database was searched for additional 19 dogs diagnosed with other spinal lesions other than SAD that had the same MR sequences. All MR images were anonymized and evaluated by two assessors.  3D-CISS sequence appears to improve confidence in diagnosing and surgical planning (Mann-Whitney U -test: p  CSF hydrodynamics and providing more anatomical details than conventional MRI sequences. The clinical data in combination with imaging findings would limit over interpretation, when concurrent pathology within the arachnoid space is present. Schattauer GmbH Stuttgart.

Vocal sequential exchanges and intragroup spacing in the Northern Muriqui Brachyteles arachnoides hypoxanthus

OpenAIRE

Mendes,Francisco D.C.; Ades,César

2004-01-01

Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyteles arachnoides hypoxanthus were recorded at the Biological Station of Caratinga, Minas Gerais State, Brazil. Staccatos and neighs containing larger proportion of short elements were preferentially produced during short-range exchanges; neighs, produced by a larger number of participants, were typical of long-range exchanges. Staccatos emitted by animals feeding in a dispersed manner contained a ...

Symptomatic Thoracic Nerve Root Herniation into an Extradural Arachnoid Cyst : Case Report and Review of the Literature

NARCIS (Netherlands)

Shanbhag, Nagesh C.; Duyff, Ruurd F.; Groen, Rob J. M.

2017-01-01

BACKGROUND: Spinal extradural arachnoid cysts (SEACs) are relatively rare and usually asymptomatic. They preferentially are situated in the thoracic extradural space and almost always dorsal. SEACs may present with back pain and/or cord compression symptoms. Needle aspiration, needle fenestration,

Sports participation with arachnoid cysts.

Science.gov (United States)

Strahle, Jennifer; Selzer, Béla J; Geh, Ndi; Srinivasan, Dushyanth; Strahle, MaryKathryn; Martinez-Sosa, Meleine; Muraszko, Karin M; Garton, Hugh J L; Maher, Cormac O

2016-04-01

OBJECT There is currently no consensus on the safety of sports participation for patients with an intracranial arachnoid cyst (AC). The authors' goal was to define the risk of sports participation for children with this imaging finding. METHODS A survey was prospectively administered to 185 patients with ACs during a 46-month period at a single institution. Cyst size and location, treatment, sports participation, and any injuries were recorded. Eighty patients completed at least 1 subsequent survey following their initial entry into the registry, and these patients were included in a prospective registry with a mean prospective follow-up interval of 15.9 ± 8.8 months. RESULTS A total 112 patients with ACs participated in 261 sports for a cumulative duration of 4410 months or 1470 seasons. Of these, 94 patients participated in 190 contact sports for a cumulative duration of 2818 months or 939 seasons. There were no serious or catastrophic neurological injuries. Two patients presented with symptomatic subdural hygromas following minor sports injuries. In the prospective cohort, there were no neurological injuries CONCLUSIONS Permanent or catastrophic neurological injuries are very unusual in AC patients who participate in athletic activities. In most cases, sports participation by these patients is safe.

Development of intracranial hypertension after surgical management of intracranial arachnoid cyst: report of three cases and review of the literature.

LENUS (Irish Health Repository)

Kaliaperumal, Chandrasekaran

2013-11-12

To describe three cases of delayed development of intracranial hypertension (IH) after surgical treatment of intracranial arachnoid cyst, including the pathogenesis of IH and a review of the literature.

Straightening the trigeminal nerve axis by complete dissection of arachnoidal adhesion and its neuroendoscopic confirmation for trigeminal neuralgia without neurovascular compression

Directory of Open Access Journals (Sweden)

Mami Ishikawa, MD, PhD

2017-12-01

Conclusions: Straightening the trigeminal nerve axis by complete dissection of the arachnoidal adhesion around the trigeminal nerve was effective for typical trigeminal neuralgia without neurovascular compression.

DYSPHONIA AS AN UNCOMMON PRESENTATION OF PONTOCEREBELLAR CHOROID PLEXUS PAPILLOMA.

Science.gov (United States)

Rotim, Krešimir; Sajko, Tomislav; Zmajević, Marina; Šumonja, Ilijana; Grgić, Marko

2015-06-01

A case is presented of a patient with dysphonia, hearing loss and ataxia due to vestibulocochlear and vagal nerve compression by choroid plexus papilloma in the cerebellopontine angle. Choroid plexus papillomas are rare tumors usually arising in the lateral and fourth ventricle, and rarely found in the cerebellopontine angle, making the neuroimaging characteristics usually not sufficient for diagnosis. Patients usually present with headache and hydrocephalus but tumors in the cerebellopontine angle can cause vestibulocochlear dysfunction and cerebellar symptoms. Dysphonia along with hearing loss was a dominant symptom in the case presented. After complete surgical removal of the tumor, deterioration of dysphonia was noticed; it could be explained as peripheral vagal nerve neuropathy due to tumor compression and intraoperative manipulation. In this case report, we describe dysphonia as an uncommon presentation of a rare posterior fossa tumor. To our knowledge, a case of choroid plexus papilloma presenting with dysphonia has not been described before. Our case extends the differential diagnosis of dysphonia from the otorhinolaryngological to the neurosurgical field.

Motor Speech Apraxia in a 70-Year-Old Man with Left Dorsolateral Frontal Arachnoid Cyst: A [18F]FDG PET-CT Study

Directory of Open Access Journals (Sweden)

Nicolaas I. Bohnen

2016-01-01

Full Text Available Motor speech apraxia is a speech disorder of impaired syllable sequencing which, when seen with advancing age, is suggestive of a neurodegenerative process affecting cortical structures in the left frontal lobe. Arachnoid cysts can be associated with neurologic symptoms due to compression of underlying brain structures though indications for surgical intervention are unclear. We present the case of a 70-year-old man who presented with a two-year history of speech changes along with decreased initiation and talkativeness, shorter utterances, and dysnomia. [18F]Fluorodeoxyglucose (FDG Positron Emission and Computed Tomography (PET-CT and magnetic resonance imaging (MRI showed very focal left frontal cortical hypometabolism immediately adjacent to an arachnoid cyst but no specific evidence of a neurodegenerative process.

The Significance of Arachnoid Granulation in Patients With Idiopathic Intracranial Hypertension.

Science.gov (United States)

Watane, Gaurav Vishwasrao; Patel, Bhumi; Brown, Derek; Taheri, M Reza

The aim of this article was to study the significance of arachnoid granulations (AGs) in patients with idiopathic intracranial hypertension (IIH). In an institutional review board-approved retrospective chart review study, 79 patients with clinical diagnosis of idiopathic increased intracranial pressure were compared with 63 patients with a diagnosis of multiple sclerosis. Inclusion criteria also included available magnetic resonance imaging (MRI) of the brain, older than 18 years, and female sex. Patients with elevated intracranial pressure due to other causes were excluded. The electronic medical records were mined for presence of the following: body mass index, age, headache, vision changes, tinnitus, and vertigo. The MRI of the brain was reviewed for the presence of the following features: empty sella, prominent cerebrospinal fluid space in the optic sheaths, tortuosity of the optic nerves and enlarged Meckel cave. In addition, the number, size, and location of AGs associated with major venous drainage sinuses were documented in all patients. Using statistical analysis, association between various imaging and clinical signs were evaluated. The association between AG and various imaging and clinical signs were evaluated. The percentage of patients with AG were significantly higher in patients with IIH. Patients with IIH tended to have 0 to 3 AG. The most common imaging findings observed in MRI of the brain of patients with IIH were empty sella and prominent cerebrospinal fluid space in the optic sheaths. The prevalence of these MRI findings in patients with IIH was inversely proportional to the number of AG. A similar inverse trend was also noted with the opening pressure of patients with IIH and number of AG. The study establishes that there is a relationship between presence of AG and IIH. Arachnoid granulation seems to act in a compensatory mechanism in patients with IIH.

Middle fossa arachnoid cyst with temporal lobe agenesis accompanying isodense subdural hematoma -a case report-

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Soo; Choi, Hyung Sik; Kim, Myung Joon; Yang, Seoung Oh; Kim, Chang Jin [Capital Armed Forces General Hospital, Seongnam (Korea, Republic of)

1987-12-15

Cysts overlying the temporal lobes have been well described in literature. These are often associated with agenesis of the temporal lobes, and of major neurosurgical interest due to their frequent association with subdural hematoma, a combination that is rarely seen with cysts in other regions. Full features of plain, angiographic, and CT findings of arachnoid cyst with temporal lobe agenesis accompanying isodense subdural hematoma are presented, being very rare in radiologic literature.

Giant posterior fossa arachnoid cyst causing tonsillar herniation and cervical syringomyelia

Directory of Open Access Journals (Sweden)

Vijay P Joshi

2013-01-01

Full Text Available Acquired cerebellar tonsillar herniation and syringomyelia associated with posterior fossa mass lesions is an exception rather than the rule. In the present article, we describe the neuroimaging findings in a case of 28-year-old female patient presented with a history of paraesthesia involving right upper limb of 8-month duration. Magnetic resonance imaging showed a giant retrocerebellar arachnoid causing tonsillar herniation with cervical syringomyelia. The findings in the present case supports that the one of the primary mechanism for the development of syringomyelia may be the obstruction to the flow of cerebrospinal fluid causing alterations in the passage of extracellular fluid in the spinal cord and leading to syringomyelia.

Arachnoid Pit and Extensive Sinus Pnematization as the Cause of Spontaneous Lateral Intrasphenoidal Encephalocele

Directory of Open Access Journals (Sweden)

Ali AlMontasheri

2012-01-01

Full Text Available Lateral sphenoid encephalocele, especially within the lateral aspect of the sphenoid sinus, when the sphenoid sinus has pneumatized extensively into the pterygoid recess, are considered exceedingly rare. We report a rare case of lateral intrasphenoidal encephalocele with spontaneous cerebral spinal fluid (CSF rhinorrhea. Computed tomography demonstrated bilateral arachnoid pit, extensive sphenoid sinus pneumatization, and a defect in the superior wall of the left lateral recess of the sphenoid sinus. Magnetic resonance imaging demonstrated anteromedial temporal lobe herniating through the bony defect.

Science.gov (United States)

Presutti, L.; Bonali, M.; Marchioni, D.; Pavesi, G.; Feletti, A.; Alicandri-Ciufelli, M.

2017-01-01

SUMMARY The aim of this paper is to describe and evaluate the feasibility of an expanded endoscopic transcanal transpromotorial approach (ExpTTA) to the internal auditory canal and the cerebellopontine angle. To this end, we performed a cadaveric dissection study in September 2015. In total, 2 heads (4 sides) were dissected focusing on anatomical landmarks and surgical feasibility. Data from dissections were reviewed and analysed for further consideration. In all 4 sides of the cadavers the procedure was feasible. In all cadavers, it was necessary to extensively drill the temporo-mandibular joint and to calibrate the external ear canal to allow adequate room to manoeuver the instruments and optics and to comfortably access the cerebellopontine angle. In addition, thorough skeletonisation of the carotid artery and the jugular bulb were necessary for the same purpose. In conclusion, ExpTTA appeared to be successful to access the internal auditory canal and cerebellopontine angle region. Potential extensive and routine application of this type of approach in lateral skull base surgery will depend on the development of technology and surgical refinements and on the diffusion of skull base endoscopic skills among otolaryngologists and neurosurgical community. PMID:28516966

Patologia comparada de Brachyteles arachnoides e Brachyteles hypoxantus (E. Geoffroy, 1806, Atelidae - Primates)

OpenAIRE

Stéfanie Vanessa Santos

2011-01-01

O gênero Brachyteles, endêmico do Brasil, é constituído por duas espécies, B. arachnoides e B. hypoxantus, e estudos recentes demonstraram que suas populações selvagens podem estar seriamente reduzidas. Na tentativa de reverter a situação atual, esforços têm sito realizados visando a conservação dos muriquis, no entanto, dados relativos à condição sanitária de Brachyteles são extremamente escassos. Sabe-se, que o estabelecimento de protocolos adequados de manejo é condição necessária para a m...

Vocal sequential exchanges and intragroup spacing in the Northern Muriqui Brachyteles arachnoides hypoxanthus.

Science.gov (United States)

Mendes, Francisco D C; Ades, César

2004-06-01

Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyteles arachnoides hypoxanthus were recorded at the Biological Station of Caratinga, Minas Gerais State, Brazil. Staccatos and neighs containing larger proportion of short elements were preferentially produced during short-range exchanges; neighs, produced by a larger number of participants, were typical of long-range exchanges. Staccatos emitted by animals feeding in a dispersed manner contained a larger proportion of tonal elements than those emitted by muriquis feeding in a cohesive manner. Sequential exchanges seem thus to be constituted by two inter-related subsystems of calls that aid muriquis to coordinate intragroup spacing, despite the poor visibility of the habitat.

Diet of a muriqui group (Brachyteles arachnoides) in continuous primary forest.

Science.gov (United States)

de Carvalho, Oswaldo; Ferrari, Stephen F; Strier, Karen B

2004-07-01

The feeding behaviour of a group of free-ranging muriquis (Brachyteles arachnoides) was monitored in the 380 km(2) Carlos Botelho State Park (PECB), between February 1992 and November 1993. Scan sample data indicated that 59.1% of feeding time was devoted to fruit, 33.2% to leaves, 4.1% to flowers, and 3.6% to other items (twigs, stem and bark). Little seasonal variation was recorded. These results contrast with those of all previous studies of Brachyteles, in which the consumption of leaves was generally double that of fruit. One key difference in comparison with previous studies is that the PECB is part of the largest remaining continuous area of primary Atlantic forest, in the Serra do Mar coastal range. Such intraspecific differences in ecology may have important implications for the conservation of the species.

Effects of patch size on feeding associations in muriquis (Brachyteles arachnoides).

Science.gov (United States)

Strier, K B

1989-01-01

Data were collected on one group of muriquis, or woolly spider monkeys (Brachyteles arachnoides) during a 14-month study at Fazenda Montes Claros, Minas Gerais, Brazil to examine the effects of food patch size on muriqui feeding associations. Muriqui food patches were larger than expected from the availability of patch sizes in the forest; fruit patches were significantly larger than leaf patches. Feeding aggregate size, the maximum number of simultaneous occupants, and patch occupancy time were positively related to the size of fruit patches. However, a greater number of individuals fed at leaf sources than expected from the size of these patches. Adult females tended to feed alone in patches more often than males, whereas males tended to feed in single-sexed groups more often than females. Yet in neither case were these differences statistically significant.

Vocal sequential exchanges and intragroup spacing in the Northern Muriqui Brachyteles arachnoides hypoxanthus

Directory of Open Access Journals (Sweden)

Mendes Francisco D.C.

2004-01-01

Full Text Available Sequential exchanges of vocalizations (staccatos and neighs emitted by Northern Muriquis Brachyteles arachnoides hypoxanthus were recorded at the Biological Station of Caratinga, Minas Gerais State, Brazil. Staccatos and neighs containing larger proportion of short elements were preferentially produced during short-range exchanges; neighs, produced by a larger number of participants, were typical of long-range exchanges. Staccatos emitted by animals feeding in a dispersed manner contained a larger proportion of tonal elements than those emitted by muriquis feeding in a cohesive manner. Sequential exchanges seem thus to be constituted by two inter-related subsystems of calls that aid muriquis to coordinate intragroup spacing, despite the poor visibility of the habitat.

Detection of Toxoplasma gondii in two southern Wooly spider monkeys (Brachyteles arachnoides-Geoffroy, 1806) from the Rio de Janeiro primate center, Brazil.

Science.gov (United States)

Santos, S V; Strefezzi, R F; Pissinatti, A; Kanamura, C T; Takakura, C F H; Duarte, M I S; Catão-Dias, J L

2014-04-01

Toxoplasmosis led to the death of two Brachyteles arachnoides, an endangered atelid. The diagnosis was established by necropsy, histopathological, immunohistochemical and ultrastructural changes. The analysis confirms the presence of Toxoplasma gondii. This report contributes to the development of protocols for health surveillance on maintenance and conservation of southern muriquis.

CT examination of expanding processes in cerebellopontine angle

International Nuclear Information System (INIS)

Bauer, J.; Kvicala, V.; Faltynova, E.

1988-01-01

A contribution is evaluated of computerized tomography to the diagnosis of expanding processes localized in the pontocerebellar corner of posterior cranial fossa, particularly neurinomas of n. statoacousticus. In cases of expanding processes in this region, especially in minor expansions, CT examination must be performed in a specially selected way, always after the intravenous administration of a contrast agent. The diagnosis of small neurinomas of n. statoacousticus, localized mostly in intracanalicullar portion, in the external auditory duct proved to be particularly difficult. In these cases, computerized pneumomeatography proved to be of a particular value; CT examination of the internal auditory duct and its neighbourhood was performed after previous filling of this region with air which, in most cases, well differentiated expansions into adjacent structures. It is confirmed in agreement with reports in the literature, that in cases of serious clinical suspicion and negative or controversial finding by classical CT examination, computerized pneumomeatography is the method of choice in the diagnosis of small isodense neurinomas of nervus statoacousticus. (author). 10 refs

Área de vida e padroes de deslocamento de Brachyteles arachnoides (E.Geoffroy, 1806) (Primates:Atelinae) em um fragmento florestal no Município de Castro, Estado do Paraná, Brasil

OpenAIRE

Pereira, Luiz Cezar Machado

2013-01-01

O presente estudo foi realizado na Fazenda Lagoa Alegre, Castro, Estado do Paraná, onde um grupo de Brachyteles arachnoides (E. Geoffroy, 1806), (mono-carvoeiro) composto por 24 indivíduos foi acompanhado entre janeiro de 2002 a outubro de 2005. O uso do habitat por Brachyteles arachnoides foi estudado numa área fragmentada de 370 hectares de Floresta Ombrófila Densa ecótono com a Floresta Ombrófila Mista (área de tensão ecológica). Ao estudo da área de vida, também foi efetivado uma breve de...

Malignant transformation of clival chordoma after gamma knife surgery. Case report

International Nuclear Information System (INIS)

Tsuboi, Yoshifumi; Hayashi, Nakamasa; Kurimoto, Masanori; Nagai, Shoichi; Sasahara, Masakiyo; Endo, Shunro

2007-01-01

A 54-year-old woman presented a midline clival tumor manifesting as right abducens palsy in May 1997. Magnetic resonance (MR) imaging revealed a midline clival tumor. She underwent surgery twice with the transsphenoidal approach and gamma knife surgery for residual tumor. The histological diagnosis was chordoma. MR imaging revealed that the tumor had extended to the right cerebellopontine angle, with spinal seeding in February 2002. She underwent partial removal of the right cerebellopontine angle tumor. The histological diagnosis was chordoma with slight nuclear atypism. She died 5 years and 5 months after the first gamma knife surgery. Autopsy revealed multiple areas of spinal seeding. Histological examination confirmed malignant transformation with unique epithelial characteristics, possibly caused by gamma knife surgery. (author)

Fatal toxoplasmosis in a southern muriqui (Brachyteles arachnoides) from São Paulo state, Brazil: Pathological, immunohistochemical, and molecular characterization.

Science.gov (United States)

Santos, Stéfanie Vanessa; Pena, Hilda F J; Talebi, Mauricio G; Teixeira, Rodrigo H F; Kanamura, Cristina T; Diaz-Delgado, Josué; Gennari, Solange M; Catão-Dias, José Luiz

2018-04-01

We report the pathological, immunohistochemical, and molecular features of fatal acute systemic toxoplasmosis in an adult, female, free-living southern muriqui (Brachyteles arachnoides) from São Paulo state, Brazil. PCR-RFLP genotyping analysis identified the #21 genotype of Toxoplasma gondii. This represents the first report of acute toxoplasmosis involving this genotype in humans and animals. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Solitary Metastasis to the Facial/Vestibulocochlear Nerve Complex: Case Report and Review of the Literature.

Science.gov (United States)

Ariai, M Shafie; Eggers, Scott D; Giannini, Caterina; Driscoll, Colin L W; Link, Michael J

2015-10-01

Distant metastasis of mucinous adenocarcinoma from the gastrointestinal tract, ovaries, pancreas, lungs, breast, or urogenital system is a well-described entity. Mucinous adenocarcinomas from different primary sites are histologically identical with gland cells producing a copious amount of mucin. This report describes a very rare solitary metastasis of a mucinous adenocarcinoma of unknown origin to the facial/vestibulocochlear nerve complex in the cerebellopontine angle. A 71-year-old woman presented with several month history of progressive neurological decline and a negative extensive workup performed elsewhere. She presented to our institution with complete left facial weakness, left-sided deafness, gait unsteadiness, headache and anorexia. A repeat magnetic resonance imaging scan of the head revealed a cystic, enhancing abnormality involving the left cerebellopontine angle and internal auditory canal. A left retrosigmoid craniotomy was performed and the lesion was completely resected. The final pathology was a mucinous adenocarcinoma of indeterminate origin. Postoperatively, the patient continued with her preoperative deficits and subsequently died of her systemic disease 6 weeks after discharge. The facial/vestibulocochlear nerve complex is an unusual location for metastatic disease in the central nervous system. Clinicians should consider metastatic tumor as the possible etiology of an unusual appearing mass in this location causing profound neurological deficits. The prognosis after metastatic mucinous adenocarcinoma to the cranial nerves in the cerebellopontine angle may be poor. Copyright © 2015 Elsevier Inc. All rights reserved.

Phylogenetic inferences of Atelinae (Platyrrhini) based on multi-directional chromosome painting in Brachyteles arachnoides, Ateles paniscus paniscus and Ateles b. marginatus

OpenAIRE

de Oliveira, EHC; Neusser, M.; Pieczarka, J. C.; Nagamachi, C.; Sbalqueiro, I. J.; Müller, Stefan

2005-01-01

We performed multi-directional chromosome painting in a comparative cytogenetic study of the three Atelinae species Brachyteles arachnoides, Ateles paniscus paniscus and Ateles belzebuth marginatus, in order to reconstruct phylogenetic relationships within this Platyrrhini subfamily. Comparative chromosome maps between these species were established by multi-color fluorescence in situ hybridization ( FISH) employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes....

Microvascular anatomy of the cerebellar parafloccular perforating space.

Science.gov (United States)

Sosa, Pablo; Dujovny, Manuel; Onyekachi, Ibe; Sockwell, Noressia; Cremaschi, Fabián; Savastano, Luis E

2016-02-01

The cerebellopontine angle is a common site for tumor growth and vascular pathologies requiring surgical manipulations that jeopardize cranial nerve integrity and cerebellar and brainstem perfusion. To date, a detailed study of vessels perforating the cisternal surface of the middle cerebellar peduncle-namely, the paraflocculus or parafloccular perforating space-has yet to be published. In this report, the perforating vessels of the anterior inferior cerebellar artery (AICA) in the parafloccular space, or on the cisternal surface of the middle cerebellar peduncle, are described to elucidate their relevance pertaining to microsurgery and the different pathologies that occur at the cerebellopontine angle. Fourteen cadaveric cerebellopontine cisterns (CPCs) were studied. Anatomical dissections and analysis of the perforating arteries of the AICA and posterior inferior cerebellar artery at the parafloccular space were recorded using direct visualization by surgical microscope, optical histology, and scanning electron microscope. A comprehensive review of the English-language and Spanish-language literature was also performed, and findings related to anatomy, histology, physiology, neurology, neuroradiology, microsurgery, and endovascular surgery pertaining to the cerebellar flocculus or parafloccular spaces are summarized. A total of 298 perforating arteries were found in the dissected specimens, with a minimum of 15 to a maximum of 26 vessels per parafloccular perforating space. The average outer diameter of the cisternal portion of the perforating arteries was 0.11 ± 0.042 mm (mean ± SD) and the average length was 2.84 ± 1.2 mm. Detailed schematics and the surgical anatomy of the perforating vessels at the CPC and their clinical relevance are reported. The parafloccular space is a key entry point for many perforating vessels toward the middle cerebellar peduncle and lateral brainstem, and it must be respected and protected during surgical approaches to the

Aneurysmal sub-arachnoid haemorrhage in patients with Noonan syndrome: a report of two cases and review of neurovascular presentations in this syndrome

International Nuclear Information System (INIS)

Dineen, R.A.; Lenthall, R.K.

2004-01-01

To date, intracranial aneurysms have been reported in two patients with Noonan syndrome. We report two unrelated patients with Noonan syndrome who presented with sub-arachnoid haemorrhage secondary to intracranial aneurysms. These cases are discussed and other cerebrovascular abnormalities that have been described in association with Noonan syndrome are reviewed. Ultrastructural and genetic factors contributing to these associations are considered. (orig.)

Aneurysmal sub-arachnoid haemorrhage in patients with Noonan syndrome: a report of two cases and review of neurovascular presentations in this syndrome

Energy Technology Data Exchange (ETDEWEB)

Dineen, R.A.; Lenthall, R.K. [Department of Radiology, University Hospital, Queen' s Medical Centre, NG7 2UH, Nottingham (United Kingdom)

2004-04-01

To date, intracranial aneurysms have been reported in two patients with Noonan syndrome. We report two unrelated patients with Noonan syndrome who presented with sub-arachnoid haemorrhage secondary to intracranial aneurysms. These cases are discussed and other cerebrovascular abnormalities that have been described in association with Noonan syndrome are reviewed. Ultrastructural and genetic factors contributing to these associations are considered. (orig.)

Multiple meningiomas CASE SERIES

African Journals Online (AJOL)

masses in the right parietal and parasagittal region (Figs 1a and b). Case 2: A ... scan showed hyperdense parasagittal and left cerebellopontine angle meningiomas (Figs ... Meningiomas are the most common primary non-glial brain tumours.

Posterior fossa meningioma (surgical experiences) | Moussa ...

African Journals Online (AJOL)

Symptoms included headache (75%), cerebellar manifestations (60%), cranial nerve affection (40%) and hearing disturbances (15%). Most of the cases (50%) were cerebellopontine angle meningioma while the least (5%) were foramen magnum meningioma. Surgical approaches used included retrosigmoid approach ...

Espasmo hemifacial: resultados do tratamento cirúrgico em 14 casos Hemifacial spasm: report of 14 cases submitted to surgical treatment

Directory of Open Access Journals (Sweden)

Rui R. D. Carvalho

1973-06-01

Full Text Available Quatorze pacientes com espasmo hemifacial foram submetidos a exploração cirúrgica e neurolise do 7º par craniano no ângulo ponto-cerebelar. Em 7 pacientes havia indubitável compressão do nervo facial por alça anômala da artéria cerebelar anterior e inferior sendo que um paciente também apresentava malformação de Arnold-Chiari. Em um paciente havia aracnoidite envolvendo o nervo. Em 6 outros, o nervo achava-se aparentemente livre. Houve alívio imediato e duradouro do espasmo em 10 pacientes, 2 permaneceram inalterados e um apresentou recidiva após 10 meses. Houve um óbito no pós-operatório imediato, conseqüente a traumatismo craniano por queda do paciente.Fourteen patients with hemifacial spasm were submitted to surgical exposure and neurolysis of the seventh nerve at the cerebellopontine angle. Seven patients had an anomalous anterior inferior cerebellar artery pulsating on the nerve, being present in one patient also Arnold-Chiari malformation. Another patient had chronic arachnoiditis involving the facial nerve. In 6 patients no abnormalities were found in the posterior fossa. There was complete relief of the spasm in 10 patients, 2 were unchanged, 1 had recurrence 10 months later and 1 died in the post-operative period due to head injury sustained during a fall.

Radioisotopic studies of the sub-arachnoid space in cerebral cysticercosis; correlation of scintigraphic with pneumoencephalographic findings

International Nuclear Information System (INIS)

Oswaldo Loayza, A.

1976-01-01

Cerabral cysticercosis is a grave public health problem in Ecuador and is caused by a tapeworm, which is parasite of man. The larvae of this tapeworm lodge in various tissues, notably in the brain, causing blockage of the sub-arachnoid space and leading to epileptic seizures and to mental deterioration. The present investigation on 115 patients has compared clinical and radiological findings with those from radionuclide cisternography, performed with a gamma camera after injection of 15-200μCi 131 I-albumin into the cerebro-spinal fluid. The results from 86 patients have been selected for detailed analysis. Radiological techniques such as pneumoencephalography were in general found to be more precise in determining the site of obstruction than cisternography

Metrizamide cisternography in the diagnosis of acoustic neurinomas

Energy Technology Data Exchange (ETDEWEB)

Servo, A.; Porras, M.; Jaeaeskinen, J.

1981-02-01

Seventy-three cisternographies with metrizamide were performed on 69 patients, mainly for diagnosis of an acoustic neurinoma. Of the 31 patients with pathological findings on cisternography 26 underwent surgery for 23 acoustic neurinomas, one neurinoma of the facial nerve, and two meningiomas. For diagnosing small tumours of the cerebellopontine cistern, cisternography is superior to all other neuroradiological methods. Tomography of the porus acusticus internus and CT scanning are the initial radiological methods in patients with signs of cerebellopontine angle lesions; if no lesion is disclosed by these two methods cisternography with metrizamide should be performed to exclude a small tumor, particularly a small acoustic neurinoma.

Anterior Inferior Cerebellar Arteries Juxtaposed with the Internal Acoustic Meatus and Their Relationship to the Cranial Nerve VII/VIII Complex.

Science.gov (United States)

Alonso, Fernando; Kassem, Mohammad W; Iwanaga, Joe; Oskouian, Rod J; Loukas, Marios; Demerdash, Amin; Tubbs, R Shane

2017-08-16

Vascular loops in the cerebellopontine angle (CPA) and their relationship to cranial nerves have been used to explain neurological symptoms. The anterior inferior cerebellar artery (AICA) has variable branches producing vascular loops that can compress the facial cranial nerve (CN) VII and vestibulocochlear (CN VIII) nerves. AICA compression of the facial-vestibulocochlear nerve complex can lead to various clinical presentations, including hemifacial spasm (HFS), tinnitus, and hemiataxia. The formation of arterial loops inside or outside of the internal auditory meatus (IAM) can cause abutment or compression of CN VII and CN VIII. Twenty-five (50 sides) fresh adult cadavers underwent dissection of the cerebellopontine angle in the supine position. In regard to relationships between the AICA and the nerves of the facial/vestibulocochlear complex, 33 arteries (66%) traveled in a plane between the facial/nervus intermedius nerves and the cochlear and vestibular nerves. Five arteries (10%) traveled below the CN VII/VIII complex, six (12%) traveled posterior to the nerve complex, four (8%) formed a semi-circle around the upper half of the nerve complex, and two (4%) traveled between and partially separated the nervus intermedius and facial nerve proper. Our study found that the majority of AICA will travel in a plane between the facial/nervus intermedius nerves and the cochlear and vestibular nerves. Although the relationship between the AICA and porus acusticus and AICA and the nerves of the CN VII/VIII complex are variable, based on our findings, some themes exist. Surgeons should consider these with approaches to the cerebellopontine angle.

A new population of the endangered Brachyteles arachnoides (É. Geoffroy, 1806) (Primates: Atelidae) in the state of Paraná, southern Brazil

OpenAIRE

Ingberman, Bianca; Kaminski, Nicholas; Fusco-Costa, Roberto; Monteiro-Filho, Emygdio

2016-01-01

The endangered southern muriqui or mono [Brachyteles arachnoides (É. Geoffroy, 1806)], is a primate endemic to the Atlantic Forest of Brazil. One known extant population is found at the southern limit of its distribution, in the state of Paraná, where it is regionally classified as Critically Endangered. Here, we report on a new population in southern Brazil. Additionally, we express our concern about the conservation status of this species in Paraná, because both populations are in small, is...

Malignant Transformation Six Months after Removal of Intracranial Epidermoid Cyst: A Case Report

Directory of Open Access Journals (Sweden)

Fayçal Lakhdar

2011-01-01

Full Text Available Intracranial epidermoid cysts are uncommon benign tumors of developmental origin; malignant transformation of benign epidermoid cysts is rare, and their prognosis remains poor. We report a case of squamous cell carcinoma arising in the cerebellopontine angle. A 52-year-old man presented with left facial paralysis and cerebellar ataxia. He had undergone total removal of a benign epidermoid cyst six months previously. Postoperative magnetic resonance imaging of the brain revealed a heterogeneous and cystic lesion in the left cerebellopontine angle with hydrocephalus. The cyst wall was enhanced by gadolinium. He underwent ventricle-peritoneal shunt and removal again; the histopathological examination revealed a squamous cell carcinoma possibly arising from an underlying epidermoid cyst. This entity is being reported for its rarity. The presence of contrast enhancement at the site of an epidermoid cyst combined with an acute, progressive neurological deficit should alert the neurosurgeon to the possibility of a malignant transformation.

''Dural tail'' adjacent to acoustic neuroma on MRI: a case report

International Nuclear Information System (INIS)

Lunardi, P.; Mastronardi, L.; Nardacci, B.; Acqui, M.; Fortuna, A.

1993-01-01

A 'dural tail' on Gd-DTPA-enhanced MRI has been often observed adjacent to meningiomas and considered to be useful in distinguishing meningioma of the cerebellopontine angle from acoustic neuroma. However, demonstration of a dural tail adjacent to an acoustic neuroma indicates that this sign is not specific. (orig.)

Case report

African Journals Online (AJOL)

abp

2014-07-27

Jul 27, 2014 ... It was a pearly tumor. The histological examination confirms the epidermoid cyst. Discussion. The Epidermoid cyst is a rare and slow growing brain tumor. It represents approximately 1% of all intracranial tumors. This lesion is known to be often located in the Cerebellopontine angle whereas dermoid cyst ...

神经内镜下桥小脑角区手术入路的解剖学研究%Anatomical study of surgical approach to cerebellopontine angle under neuroendoscope

Institute of Scientific and Technical Information of China (English)

宋英; 师蔚; 马向科

2011-01-01

Objective To evaluate the application of three kinds of approach to the cerebellopontine angle under neuroendoscope. Methods Suboccipital retrosigmoid extracerebellar keyhole approach, suboccipital retrosigmoid infratentorial-supracerebellar keyhole approach and suboccipital retrosigmoid inferior floccular process keyhole approach were simulated under neuroendoscope respectively, and the surgical routes and anatomical landmarks to the root exit/entry zoon (REZ) of the V , Ⅳ, K cranial nerves were defined. Results The REZ of the cranial nerves V, VII and IX were observed through the suboccipital retrosigmoid extracerebellar keyhole approach, and the landmarks covered Meckel cave, internal auditory foramen, jugular foramen and cranial nerves V, Ⅳ, Ⅷ, K. The structure from the REZ of cranial nerve V to Meckel cave were explored through suboccipital retrosigmoid infratentorial-supracerebellar keyhole approach, and the landmarks covered the petrosal vein, cranial nerve V and Meckel cave. The REZ of the cranial nerves K and VD were explored via suboccipital retrosigmoid infrafloccular process keyhole approach, and the landmarks covered the choroid plexus of the fourth ventricle and floccular process. Conclusions Infratentorial-supracerebellar keyhole approach is superior to extracerebellar keyhole approach for microvascular decompression of the cranial nerve V, while infrafloccular process keyhole approach is superior to extracerebellar keyhole approach for microvascular decompression of the cranial nerve VD or IX.%目的 探讨神经内镜下桥小脑角区3种手术入路的应用价值.方法 在神经内镜下分别模拟枕下乙状窦后小脑外侧锁孔入路、枕下乙状窦后幕下小脑上锁孔入路、枕下乙状窦后绒球下锁孔入路,确定到三叉神经出入脑干区(REZ)、面神经REZ及舌咽神经REZ的手术路径及解剖定位标志.结果 �

Cine-magnetic resonance imaging evaluation of communication between middle cranial fossa arachnoid cysts and cisterns

International Nuclear Information System (INIS)

Eguchi, Takahiko; Nikaido, Yuji; Shiomi, Kazuaki; Fujimoto, Takatoshi; Otsuka, Hiroyuki; Takeuchi, Hiroshi; Taoka, Toshiaki.

1996-01-01

Cine-magnetic resonance (MR) imaging examinations were performed in 10 patients with middle cranial fossa arachnoid cysts to evaluate communication between the cysts and the normal cerebrospinal fluid (CSF) space. Eight of 10 patients were evaluated by time of flight cine-MR imaging, and two by phase contrast cine-MR imaging. Two patients underwent membranectomy of the cysts, and were evaluated both pre-and postoperatively. Computed tomography cisternography was used to confirm communication between the cysts and the surrounding cisterns. Pulsatile fluid motion within the cysts was present in all patients. However, marked fluid motion and jet flow between the cysts and the surrounding cisterns were only observed in communicating cysts. In the two patients who underwent membranectomy, postoperative examination found greater fluid motion and jet flow not previously present. Cine-MR imaging demonstration of marked pulsatile fluid motion accompanied by jet flow suggests that a cyst communicates with the normal CSF space. (author)

Haemorrhagic acoustic neuroma with features of a vascular malformation. A case report

Energy Technology Data Exchange (ETDEWEB)

Benhaiem-Sigaux, N. [Dept. of Pathology, Hopital Henri Mondor, Creteil (France); Ricolfi, F. [Dept. of Neuroradiology, Henri Mondor Hospital, Creteil (France); Torres-Diaz, A.; Keravel, Y. [Dept. of Neurosurgery, Henri Mondo Hospital, Creteil (France); Poirier, J. [Dept. of Histology, Pitie-Salpetriere Hospital, Paris (France)

1999-10-01

A 55-year-old man with hearing loss presented with vertigo and vomiting. CT tomography and MRI demonstrated a cerebellopontine angle mass with foci of haemorrhage. An angiomatous tumour, with large abnormal veins adhering to the capsule, was completely removed. Histologically, the tumour was an acoustic neuroma with abnormal vascularisation and limited intratumoral haemorrhage. (orig.)

Intracranial route of a cervical neuroblastoma through skull base foramina

International Nuclear Information System (INIS)

Goldberg, R.M.; Keller, I.A.; Schonfeld, S.M.; Mezrich, R.S.; Rosenfeld, D.L.

1996-01-01

A case of primary cervical neuroblastoma gaining access to the cerebellopontine angle via direct perineural spread is described. MRI effectively delineated soft tissues, while CT demonstrated tumor calcifications and the integrity of adjacent bones. Both imaging modalities were beneficial in predicting the unique histology and pattern of disease confirmed at surgery. (orig.). With 1 fig

Haemorrhagic acoustic neuroma with features of a vascular malformation. A case report

International Nuclear Information System (INIS)

Benhaiem-Sigaux, N.; Ricolfi, F.; Torres-Diaz, A.; Keravel, Y.; Poirier, J.

1999-01-01

A 55-year-old man with hearing loss presented with vertigo and vomiting. CT tomography and MRI demonstrated a cerebellopontine angle mass with foci of haemorrhage. An angiomatous tumour, with large abnormal veins adhering to the capsule, was completely removed. Histologically, the tumour was an acoustic neuroma with abnormal vascularisation and limited intratumoral haemorrhage. (orig.)

Atypical Manifestation of Vestibular Schwannoma

Directory of Open Access Journals (Sweden)

Webster, Guilherme

2013-09-01

Full Text Available Introduction: Vestibular schwannoma (also known as acoustic neuroma is a benign tumor whose cells are derived from Schwann sheaths, which commonly occurs from the vestibular portion of the eighth cranial nerve. Furthermore, vestibular schwannomas account for ∼8% of intracranial tumors in adults and 80 to 90% of tumors of the cerebellopontine angle. Its symptoms are varied, but what stands out most is a unilateral sensorineural hearing loss, with a low index of speech recognition. Objective: Describe an atypical manifestation of vestibular schwannoma. Case Report: The 46-year-old woman had vertigo and binaural hearing loss and fullness, with ear, nose, and throat examination suggestive of cochlear injury. After 6 months, the patient developed worsening of symptoms and onset of right unilateral tinnitus. In further exams the signs of cochlear damage remained, except for the vestibular test (hyporeflexia. Magnetic resonance imaging showed an expansive lesion in the right cerebellopontine angle. Discussion: This report warns about the atypical manifestations of vestibular schwannoma, which must always be remembered in investigating and diagnosing hearing loss.

Relevance and therapy of intracranial arachnoidal cysts; Relevanz und Therapie intrakranieller Arachnoidalzysten

Energy Technology Data Exchange (ETDEWEB)

Eymann, R. [Universitaetsklinikum des Saarlandes, Klinik fuer Neurochirurgie, Homburg/Saar (Germany); Kiefer, M. [Universitaet des Saarlandes, Homburg/Saar (Germany)

2018-02-15

Intracranial arachnoidal cysts (AC) are relevant due to their space-demanding character. The pathophysiological sequelae are dependent on the size and location of the cyst and the patient's age. Direct pressure on surrounding tissue causes headaches (meninges) or rarely seizures (brain tissue). Cerebrospinal fluid (CSF) circulation disturbances resulting from brain mass displacement with occlusion of, for example, the foramen monroi or the aqueduct cause occlusive hydrocephalus, which can lead to an increase in intracranial pressure. Depending on age, the typical primary clinical symptoms or findings differ. In adults and older children, headaches are usually the first clinical symptom. Children, in whom skull growth is not yet complete, present with a head circumference above the 97th percentile. An abnormal one-sided deflection of the calotte in the region of the underlying AC may also be present. Cranial magnetic resonance imaging (cMRI), the first-line diagnostic tool of choice to demonstrate size and location of the cysts and the surrounding intracranial structures, is of utmost importance for therapy planning. In addition, further malformations can be detected. Moreover, cMRI may also be useful for a rough assessment of increased intracranial pressure (ICP). In most symptomatic AC, surgical treatment is unavoidable. The primarily goal is to establish communication between the CSF and the cysts' content in order to effect pressure equalization. If the CSF reabsorption capacity is insufficient, it may also be necessary to implant a CSF shunt. Asymptomatic arachnoidal cysts should be strictly followed clinically and by cMRI over time. The reasonable frequency for follow-up depends on the size and location of the cyst. (orig.) [German] Die Relevanz intrakranieller Arachnoidalzysten (AC) ergibt sich aus ihrem raumfordernden Charakter. Die pathophysiologischen Folgen ergeben sich aus der Groesse und Lage der Zyste sowie dem Alter des Patienten. Durch den

Primary ectopic frontotemporal extradural craniopharyngioma

Directory of Open Access Journals (Sweden)

Reza Pourkhalili

2016-01-01

Full Text Available We present a case of primary ectopic frontotemporal extradural craniopharyngioma. Primary ectopic craniopharyngiomas are very rare and have been reported involving the fourth ventricle, infrasellar region, lateral ventricle, temporal area, cerebellopontine angle, clivus, corpus callosum, and prepontine cistern. There was just 1 case of craniopharyngioma previously presented in the literature, with nearly same location as the presenting case.

Bells against palsy.

Science.gov (United States)

Williams, J D; Lehman, R

1988-01-01

A technique is described in which "jingle bells" are sutured in three positions on the face at the points of maximum excursion of the facial musculature when stimulated by a Hilger nerve stimulator set at 2 mA. The procedure is used to monitor movement of the facial nerve while the surgeon dissects the nerve in the cerebellopontine angle and internal auditory canal.

Microvascular decompression for trigeminal neuralgia

International Nuclear Information System (INIS)

Khan, S.A.; Khan, B.; Khan, A.A.; Afridi, E.A.A.; Mehmood, S.; Muhammad, G.; Hussain, I.; Zadran, K.K.; Bhatti, S.N.

2015-01-01

Background: Trigeminal Neuralgia (TGN) is the most frequently diagnosed type of facial pain. In idiopathic type of TGN it is caused by the neuro-vascular conflict involving trigeminal nerve. Microvascular decompression (MVD) aims at addressing this basic pathology in the idiopathic type of TGN. This study was conducted to determine the outcome and complications of patients with idiopathic TGN undergoing MVD. Method: In a descriptive case series patients with idiopathic TGN undergoing MVD were included in consecutive manner. Patients were diagnosed on the basis of detailed history and clinical examination. Retromastoid approach with craniectomy was used to access cerebellopontine angle (CP-angle) and microsurgical decompression was done. Patients were followed up for 6 months. Results: A total of 53 patients underwent MVD with mean age of 51.6±4.2 years and male predominance. In majority of cases (58.4 percentage) both Maxillary and Mandibular divisions were involved. Per-operatively superior cerebellar artery (SCA) was causing the neuro-vascular conflict in 33 (62.2 percentage) of the cases, anterior inferior cerebellar artery (AICA) in 6 (11.3 percentage) cases, both CSA and AICA in 3 (5.6 percentage) cases, venous compressions in only 1 (1.8percentage) patient and thick arachnoid adhesions were seen in 10 (18.9 percentage) patients. Postoperatively, 33 (68 percentage) patients were pain free, in 14 (26.45 percentage) patients pain was significantly improved whereas in 3 (5.6 percentage) patients there was mild improvement in symptoms. Three (5.6 percentage) patients did not improve after the primary surgery. Cerebrospinal fluid (CSF) leak was encountered in 7 (13.2 percentage) patients post-operatively, 4 (7.5 percentage) patients developed wound infection and 1 (1.8 percentage) patient developed aseptic meningitis. Three (5.6 percentage) patients had transient VII nerve palsy while one patient developed permanent VII nerve palsy. Conclusion: MVD is a safe and

Analysis of MRI in chronic alcoholics with brain atrophy

International Nuclear Information System (INIS)

Park, Jin Sook; Kim, Myung Soon; Whang, Kum

1997-01-01

To quantitatively evaluate by MRI brain atrophy and abnormal parenchymal signal intensity on T2-weighted spin echo image in alcoholics. MRI of 24 alcoholic patients were retrospectively evaluated to measure brain atrophy (cerebral sulcal width, bifrontal horn distance, third ventricular width, fourth ventricular width, ambient cistern width, cerebellopontine angle cistern width, number of cerebellar sulci, and number of vermian sulci) and abnormal high signal lesions of brain parenchyma on T2-weighted spin echo image, and were compared with age matched controls (n=29). The alcoholics and controls were divided into two age groups, younger (30-49 years) and older (50-72 years), and statistical analysis was then performed. Axial and sagittal T1- and T2-weighted spin echo images were obtained using a 0.5 Tesla superconductive system. Statistical significant parameters in the supratentorial region were cerebral sulcal width, distance between lateral ends of frontal horns of both lateral ventricles, and third ventricular width (p < 0.05), and in the infratentorial region were fourth ventricular width, ambient cistern width, cerebellopontine angle cistern width, number of cerebellar sulci, and number of vermian sulci (p < 0.05). In the younger age group, statistical significant parameters were cerebral sulcal width, third ventricular width, ambient cistern width, cerebellopontine angle cistern width, number of cerebellar sulci, and number of vermian sulci (p < 0.05) and in the older group were cerebral sulcal width, bifrontal horn distance, third ventricular width, fourth ventricular width, number of cerebellar sulci, and number of vermian sulci (p < 0.05). Abnormal high signal intensity on T2-weighted spin echo images were seen in 46% of alcoholics (11/24) and in 13% of controls (3/29). High signal lesions in the older group were statistically significant (p < 0.05). Atrophic brain changes and periventricular high signal foci on T2-weighted spin echo image are

Sport-related structural brain injury associated with arachnoid cysts: a systematic review and quantitative analysis.

Science.gov (United States)

Zuckerman, Scott L; Prather, Colin T; Yengo-Kahn, Aaron M; Solomon, Gary S; Sills, Allen K; Bonfield, Christopher M

2016-04-01

OBJECTIVE Arachnoid cysts (ACs) are congenital lesions bordered by an arachnoid membrane. Researchers have postulated that individuals with an AC demonstrate a higher rate of structural brain injury after trauma. Given the potential neurological consequences of a structural brain injury requiring neurosurgical intervention, the authors sought to perform a systematic review of sport-related structural-brain injury associated with ACs with a corresponding quantitative analysis. METHODS Titles and abstracts were searched systematically across the following databases: PubMed, Embase, CINAHL, and PsycINFO. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Peer-reviewed case reports, case series, or observational studies that reported a structural brain injury due to a sport or recreational activity (hereafter referred to as sport-related) with an associated AC were included. Patients were excluded if they did not have an AC, suffered a concussion without structural brain injury, or sustained the injury during a non-sport-related activity (e.g., fall, motor vehicle collision). Descriptive statistical analysis and time to presentation data were summarized. Univariate logistic regression models to assess predictors of neurological deficit, open craniotomy, and cystoperitoneal shunt were completed. RESULTS After an initial search of 994 original articles, 52 studies were found that reported 65 cases of sport-related structural brain injury associated with an AC. The median age at presentation was 16 years (range 4-75 years). Headache was the most common presenting symptom (98%), followed by nausea and vomiting in 49%. Thirteen patients (21%) presented with a neurological deficit, most commonly hemiparesis. Open craniotomy was the most common form of treatment (49%). Bur holes and cyst fenestration were performed in 29 (45%) and 31 (48%) patients, respectively. Seven patients (11%) received

Phylogenetic inferences of Atelinae (Platyrrhini) based on multi-directional chromosome painting in Brachyteles arachnoides, Ateles paniscus paniscus and Ateles b. marginatus.

Science.gov (United States)

de Oliveira, E H C; Neusser, M; Pieczarka, J C; Nagamachi, C; Sbalqueiro, I J; Müller, S

2005-01-01

We performed multi-directional chromosome painting in a comparative cytogenetic study of the three Atelinae species Brachyteles arachnoides, Ateles paniscus paniscus and Ateles belzebuth marginatus, in order to reconstruct phylogenetic relationships within this Platyrrhini subfamily. Comparative chromosome maps between these species were established by multi-color fluorescence in situ hybridization (FISH) employing human, Saguinus oedipus and Lagothrix lagothricha chromosome-specific probes. The three species included in this study and four previously analyzed species from all four Atelinae genera were subjected to a phylogenetic analysis on the basis of a data matrix comprised of 82 discrete chromosome characters. The results confirmed that Atelinae represent a monophyletic clade with a putative ancestral karyotype of 2n = 62 chromosomes. Phylogenetic analysis revealed an evolutionary branching sequence [Alouatta [Brachyteles [Lagothrix and Ateles

Trigemino-cardiac reflex: occurrence of asystole during trans-sphenoidal adenomectomy: a case report

OpenAIRE

Jeon, Dae Geun; Kang, Bong Jin; Hur, Tae Won

2014-01-01

The trigemino-cardiac reflex has been reported to occur during various craniofacial surgeries or procedures including manipulation of the trigeminal ganglion, tumor resection in the cerebellopontine angle, various facial reconstructions and trans-sphenoidal adenomectomy. Regarding risk factors during trans-sphenoidal adenomectomy, invasiveness closely related to the size of tumor and the degree of manipulation of cavernous sinus wall have been reported. We report the case of a 40-year-old fem...

Steroid excretion during the ovarian cycle in captive and wild muriquis, Brachyteles arachnoides.

Science.gov (United States)

Ziegler, T E; Santos, C V; Pissinatti, A; Strier, K B

1997-01-01

Urine, feces, and copulation frequency were collected from two captive muriqui females, Brachyteles arachnoides, at the Centro de Primatologia do Rio de Janeiro following the resumption of postpartum ovarian cycles. Fecal steroid profiles from seven wild muriqui females at the Estação Biologica de Caratinga, Minas Gerais, Brazil, were compared to the captive females to determine the approximate patterns of steroid excretion relative to the urinary LH peak. Hormonal profiles from one of the captive female muriquis revealed a discrete urinary LH peak. For this female, fecal progesterone increased on the same day as the urinary LH peak, while fecal estradiol increased 6 days later and urinary steroids increased 5 days later. For both captive females, the onset of fecal progesterone increase was preceded by the onset of copulations, which occurred during at least a 5-day period. The complete fecal hormonal profiles of the one captive female for which continuos data were available were similar to those found in wild muriqui monkeys, with the onset of an increase in sustained progesterone levels occurring several days prior to the onset of sustained estradiol increase. These patterns suggest that fecal progesterone may be excreted rapidly in this species. The onset of sustained increase in fecal progesterone levels, together with the consistent delay in the onset of the sustained increase in estradiol, may provide the best indicators of the periovulatory period for muriqui females.

Behavioral and endocrine characteristics of the reproductive cycle in wild muriqui monkeys, Brachyteles arachnoides.

Science.gov (United States)

Strier, K B; Ziegler, T E

1997-01-01

The analysis of fecal ovarian steroids provides a powerful noninvasive method to obtain insights into ovulatory cycles, gestation length, and the timing of sexual interactions relative to the periovulatory period in wild primates. Techniques developed to collect and assay feces from free-ranging muriqui monkeys (Brachyteles arachnoides) for estradiol and progesterone yield the first explicit reproductive data on this species, and provide the first opportunity to evaluate the timing of observed copulations with muriqui ovarian cycles. Hormonal profiles from seven females indicate average cycle lengths of 21.0 +/- 5.4 days (n = 20). Females conceived after 3-6 ovulatory cycles. Gestation length averaged 216.4 +/- 1.5 days for the five females for which conception cycles were sampled. Discrete copulation periods spanned an average of 2.1 +/- 1.2 days (n = 29), with intervals between these concentrated periods of copulations averaging 15.6 +/- 6.7 days (n = 20). There were no significant differences among females in cycle lengths, copulation period lengths, or copulation interval lengths. Ejaculation was visible following 71.8 +/- 26.7% of copulations during the females preovulatory periods. All females copulated outside the periovulatory period. The proportion of copulation days outside the periovulatory period was slightly greater (p = 0.08) for primiparous females (64.8 +/- 28.3%) than for multiparous females (28.7 +/- 19.7%).

Human arachnoid granulations Part I: a technique for quantifying area and distribution on the superior surface of the cerebral cortex

Directory of Open Access Journals (Sweden)

Holman David W

2007-07-01

Full Text Available Abstract Background The arachnoid granulations (AGs are herniations of the arachnoid membrane into the dural venous sinuses on the surface of the brain. Previous morphological studies of AGs have been limited in scope and only one has mentioned surface area measurements. The purpose of this study was to investigate the topographic distribution of AGs on the superior surface of the cerebral cortex. Methods En face images were taken of the superior surface of 35 formalin-fixed human brains. AGs were manually identified using Adobe Photoshop, with a pixel location containing an AG defined as 'positive'. A set of 25 standard fiducial points was marked on each hemisphere for a total of 50 points on each image. The points were connected on each hemisphere to create a segmented image. A standard template was created for each hemisphere by calculating the average position of the 25 fiducial points from all brains. Each segmented image was mapped to the standard template using a linear transformation. A topographic distribution map was produced by calculating the proportion of AG positive images at each pixel in the standard template. The AG surface area was calculated for each hemisphere and for the total brain superior surface. To adjust for different brain sizes, the proportional involvement of AGs was calculated by dividing the AG area by the total area. Results The total brain average surface area of AGs was 78.53 ± 13.13 mm2 (n = 35 and average AG proportional involvement was 57.71 × 10-4 ± 7.65 × 10-4. Regression analysis confirmed the reproducibility of AG identification between independent researchers with r2 = 0.97. The surface AGs were localized in the parasagittal planes that coincide with the region of the lateral lacunae. Conclusion The data obtained on the spatial distribution and en face surface area of AGs will be used in an in vitro model of CSF outflow. With an increase in the number of samples, this analysis technique can be used

Age at first reproduction in philopatric female muriquis ( Brachyteles arachnoides hypoxanthus).

Science.gov (United States)

Martins, Waldney P; Strier, Karen B

2004-01-01

Female northern muriquis ( Brachyteles arachnoides hypoxanthus or B. hypoxanthus) at the Estação Biológica de Caratinga/RPPN-FMA, Minas Gerais, Brazil typically disperse from their natal groups at an average age of 6.1+/-0.6 years (median =6.0 years, range =5.3-7.8 years, n =22), prior to the onset of puberty and sexual activity. Immigrants do not conceive until at least their second mating season, and the minimum interval from immigration to first reproduction has been 2.0 years. Age at first reproduction in dispersing females, previously estimated at 8.9 years, has now been documented at 9.0 and 9.25 years for two females whose birth dates are known. This is older than the 7.5 years at which the only female previously known to have reproduced in her natal group gave birth. Here, we present new data from a second female that reproduced in her natal group. This female (BA) was first observed to copulate at 5.5 years, and gave birth to her first infant at 7.25 years of age. Her 1.75-year cycling-to-first conception delay was only slightly shorter than the minimum recorded for immigrant females, and thus was not responsible for her young age at first reproduction compared to dispersing females. Although our sample size is small, our findings suggest that early puberty may permit females to reproduce in their natal group, implying a possible link between life history trade-offs and dispersal patterns. Because the only two females that have reproduced in their natal group were maternal sisters, it is also possible that maternal effects on age at puberty can impact dispersal patterns, particularly in small populations of primates.

New radiological examination for tumor in the internal auditory canal by combination of air CT cisternography and target imaging

Energy Technology Data Exchange (ETDEWEB)

Yagishita, A.; Shiga, I.; Kanzaki, H. (Keio Univ., Tokyo (Japan). School of Medicine)

1982-07-01

A 56-year-old man was admitted to the hospital because of progressive right hearing disturbance and tinnitus. An x-ray film of the skull demonstrated dilatation of the right internal auditory canal. Intravcnously enhanced CT didn't reveal any tumor in the right cerebellopontine angle. An intracanalicular tumor was demonstrated by air CT cisternography with target imaging, and confirmed by surgery. This method is useful for the radiological evaluation of the intracanalicular tumors.

A new radiological examination for tumor in the internal auditory canal by combination of air CT cisternography and target imaging

International Nuclear Information System (INIS)

Yagishita, Akira; Shiga, Itsuo; Kanzaki, Hitoshi

1982-01-01

A 56-year-old man was admitted to the hospital because of progressive right hearing disturbance and tinnitus. An x-ray film of the skull demonstrated dilatation of the right internal auditory canal. Intravcnously enhanced CT didn't reveal any tumor in the right cerebellopontine angle. An intracanalicular tumor was demonstrated by air CT cisternography with target imaging, and confirmed by surgery. This method is useful for the radiological evaluation of the intracanalicular tumors. (author)

New radiological examination for tumor in the internal auditory canal by combination of air CT cisternography and target imaging

Energy Technology Data Exchange (ETDEWEB)

Yagishita, A; Shiga, I; Kanzaki, H [Keio Univ., Tokyo (Japan). School of Medicine

1982-07-01

A 56-year-old man was admitted to the hospital because of progressive right hearing disturbance and tinnitus. An x-ray film of the skull demonstrated dilatation of the right internal auditory canal. Intravcnously enhanced CT didn't reveal any tumor in the right cerebellopontine angle. An intracanalicular tumor was demonstrated by air CT cisternography with target imaging, and confirmed by surgery. This method is useful for the radiological evaluation of the intracanalicular tumors.

Intra-community coalitionary lethal attack of an adult male southern muriqui (Brachyteles arachnoides).

Science.gov (United States)

Talebi, M G; Beltrão-Mendes, R; Lee, P C

2009-10-01

We report on the first evidence of intra-community coalitionary lethal aggression in muriquis (Brachyteles). The event occurred in southern muriquis (Brachyteles arachnoides) during a long-term study (>15 years) of two social groups inhabiting mostly pristine Atlantic forest habitat in the Parque Estadual Carlos Botelho, southern São Paulo State, Brazil. The attack took place deep in the core area of the Group Caetê home range. Tense agonistic behaviors and vocalizations preceded the lethal coalitionary attack, and the tension increased over a 36-48 hr period. One adult female and two unidentified individuals also took part in a coalition led by six adult males. The members of the coalition collectively approached, embraced, immobilized and repeatedly bit the entire body of an adult male, resulting in severe bleeding injuries and the victim's death in less than 1 hr after the attack commenced. Combined ecological, behavioral and spatial data related to the event indicate that this was an intra-community attack and suggest social tensions related to mating competition as the proximate trigger of the coalitionary killing. The attack resembled those reported for chimpanzees, with clear numeric superiority and a low risk of injury to aggressors, resulting in the death of a lone conspecific victim. This observation (n=1) is suggestive of a capacity for escalated aggression in muriquis and reinforces arguments for the potential adaptive significance of intra-community aggression in male philopatric societies, as reported for spider monkeys and chimpanzees. These characteristics challenge the view of the muriquis as a peaceful primate and support the general hypothesis that imbalances of power contribute to intra-specific killing in primates, such as chimpanzees and humans.

Hormonal changes during the mating and conception seasons of wild northern muriquis (Brachyteles arachnoides hypoxanthus).

Science.gov (United States)

Strier, Karen B; Lynch, Jessica W; Ziegler, Toni E

2003-10-01

We investigated hormonal and behavioral changes in wild male and female northern muriquis (Brachyteles arachnoides hypoxanthus) at the Estação Biológica de Caratinga, Minas Gerais, Brazil, during a 6-mo period that encompassed the onset of the 1998-1999 mating and conception seasons. Individual females resumed mating with the resumption of ovarian cycling, which was not synchronized among them or related to their cortisol levels. Females experienced two to seven cycles prior to conceiving, and the first conception occurred 2 mo after the onset of the group's mating season. There were no differences in female cortisol levels across their premating, mating, and conception conditions. Cortisol levels were significantly higher in females than in males prior to the conception season, consistent with the prediction that energy reserves may be associated with breeding readiness in females, but not males, in this species. The sustained elevation in male cortisol occurred after the peak in their sexual activity, which resulted in the first conception of the year. Male cortisol levels were positively correlated between years that were similar in rainfall, but differed in the timing of sexual and reproductive events. The timing of cortisol elevations in males appears to be generally regulated by environmental cues, but is responsive to fine-tuning by social and behavioral cues related to the unpredictable timing of reproductive opportunities within their extended mating season. Copyright 2003 Wiley-Liss, Inc.

Seasonal and social correlates of fecal testosterone and cortisol levels in wild male muriquis (Brachyteles arachnoides).

Science.gov (United States)

Strier, K B; Ziegler, T E; Wittwer, D J

1999-04-01

Fecal testosterone and cortisol levels were analyzed from six wild male muriquis (Brachyteles arachnoides) over a 19-month period at the Estação Biológica de Caratinga in Minas Gerais, Brazil, to investigate the hormonal correlates of seasonal sexual behavior and environmental conditions. Group mean testosterone levels based on weekly samples from the six males did not differ between copulatory and noncopulatory periods or between rainy and dry seasons. Cortisol levels did change with copulatory periods, and were significantly higher during the second dry season, when mating continued following an exceptionally heavy rainy season, than during the first dry season, when mating ceased. Males exhibited individual variation in the timing of their hormone shifts relative to their sexual activity, but neither hormone levels nor sexual activity were related to male age. Despite individual differences in the timing of testosterone fluctuations around the onset and offset of the copulatory season, all males exhibited elevated cortisol concentrations following a slight increase in testosterone at the beginning of the copulatory season. Both the lack of significant changes in testosterone levels with the onset of the rainy and copulatory season and the lack of prebreeding increases in cortisol may be related to the low levels of overt aggression displayed by male muriquis over access to mates. Copyright 1999 Academic Press.

A clinicopathological analysis of papillary endolymphatic sac tumor in inner ear

Directory of Open Access Journals (Sweden)

LIN Yu-jing

2013-05-01

Full Text Available Background Endolymphatic sac tumor (ELST is a rare tumor originating fromendolymphatic epithelium of inner ear. This tumor exhibits low-grade malignancy with benign histopathological appearance and clinically destructive behavior which occurs in the skull base and frequently invades the posterior petrous bone, the mastoid, semicircular canal, cerebellopontine angle structures and cranial nerve. The presence of intracranial ELST always makes the diagnosis challenge for clinicians and pathologists. Herein we describe a case of ELST in skull base. The clinicopathology of this tumor and its differential diagnosis are discussed. Methods The clinical manifestation of a patient with primary ELST occurring in right cerebellopontine angle was presented retrospectively. Resected mass was routinely paraffin-embedded and stained with hematoxylin and eosin. Dako EnVision immunohistochemical staining system was used to detect the tumor antigen expressions, including cytokeratin (CK, vimentin (Vim, epithelial membrane antigen (EMA, carcinoembryonic antigen (CEA, synaptophysin (Syn, chromogranin A (CgA, S-100 protein (S-100, glial fibrillary acidic protein (GFAP, thyroglobulin (TG, thyroid transcription factor-1 (TTF-1 and Ki-67. Results A 32-year-old male patient presented with 20-year history of progressive hearing loss. MRI scan revealed an expansile lytic lesion of the mastoid process of the right petrous bone, measuring 4.20 cm × 3.30 cm × 2.00 cm, occupied the right cerebellopontine angle with infiltration of surrounding dura mater. But the lesion did not break the dura mater and invade the brain parenchyma. Craniotomy was performed and the tumor was removed totally. Histological examination revealed a papillary, cystic or glandular architecture in mass. The papillary and glandular structures were lined by a single layer of flattened cuboidal-to-columnar cells. The stroma of the papillary fronds was richly vascularized and chronically inflamed. There

Equilibrium contact angle or the most-stable contact angle?

Science.gov (United States)

Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

2014-04-01

It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation. © 2013 Elsevier B.V. All rights reserved.

Drug Clearance from Cerebrospinal Fluid Mediated by Organic Anion Transporters 1 (Slc22a6) and 3 (Slc22a8) at Arachnoid Membrane of Rats.

Science.gov (United States)

Zhang, Zhengyu; Tachikawa, Masanori; Uchida, Yasuo; Terasaki, Tetsuya

2018-03-05

Although arachnoid mater epithelial cells form the blood-arachnoid barrier (BAB), acting as a blood-CSF interface, it has been generally considered that the BAB is impermeable to water-soluble substances and plays a largely passive role. Here, we aimed to clarify the function of transporters at the BAB in regulating CSF clearance of water-soluble organic anion drugs based on quantitative targeted absolute proteomics (QTAP) and in vivo analyses. Protein expression levels of 61 molecules, including 19 ATP-binding-cassette (ABC) transporters and 32 solute-carrier (SLC) transporters, were measured in plasma membrane fraction of rat leptomeninges using QTAP. Thirty-three proteins were detected; others were under the quantification limits. Expression levels of multidrug resistance protein 1 (Mdr1a/P-gp/Abcb1a) and breast cancer resistance protein (Bcrp/Abcg2) were 16.6 and 3.27 fmol/μg protein (51.9- and 9.82-fold greater than in choroid plexus, respectively). Among those organic anion transporters detected only at leptomeninges, not choroid plexus, organic anion transporter 1 (oat1/Slc22a6) showed the greatest expression (2.73 fmol/μg protein). On the other hand, the protein expression level of oat3 at leptomeninges was 6.65 fmol/μg protein, and the difference from choroid plexus was within two-fold. To investigate oat1's role, we injected para-aminohippuric acid (PAH) with or without oat1 inhibitors into cisterna magna (to minimize the contribution of choroid plexus function) of rats. A bulk flow marker, FITC-inulin, was not taken up from CSF up to 15 min, whereas uptake clearance of PAH was 26.5 μL/min. PAH uptake was completely blocked by 3 mM cephalothin (inhibits both oat1 and oat3), while 17% of PAH uptake was inhibited by 0.2 mM cephalothin (selectively inhibits oat3). These results indicate that oat1 and oat3 at the BAB provide a distinct clearance pathway of organic anion drugs from CSF independently of choroid plexus.

Longitudinal changes of angle configuration in primary angle-closure suspects: the Zhongshan Angle-Closure Prevention Trial.

Science.gov (United States)

Jiang, Yuzhen; Chang, Dolly S; Zhu, Haogang; Khawaja, Anthony P; Aung, Tin; Huang, Shengsong; Chen, Qianyun; Munoz, Beatriz; Grossi, Carlota M; He, Mingguang; Friedman, David S; Foster, Paul J

2014-09-01

To determine longitudinal changes in angle configuration in the eyes of primary angle-closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes. Longitudinal cohort study. Primary angle-closure suspects aged 50 to 70 years were enrolled in a randomized, controlled clinical trial. Each participant was treated by LPI in 1 randomly selected eye, with the fellow eye serving as a control. Angle width was assessed in a masked fashion using gonioscopy and anterior segment optical coherence tomography (AS-OCT) before and at 2 weeks, 6 months, and 18 months after LPI. Angle width in degrees was calculated from Shaffer grades assessed under static gonioscopy. Angle configuration was also evaluated using angle opening distance (AOD250, AOD500, AOD750), trabecular-iris space area (TISA500, TISA750), and angle recess area (ARA) measured in AS-OCT images. No significant difference was found in baseline measures of angle configuration between treated and untreated eyes. At 2 weeks after LPI, the drainage angle on gonioscopy widened from a mean of 13.5° at baseline to a mean of 25.7° in treated eyes, which was also confirmed by significant increases in all AS-OCT angle width measures (Pgonioscopy (P = 0.18), AOD250 (P = 0.167) and ARA (P = 0.83). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared with treated eyes (P values for all variables ≤0.003). The annual rate of change in angle width was equivalent to 1.2°/year (95% confidence interval [CI], 0.8-1.6) in treated eyes and 1.6°/year (95% CI, 1.3-2.0) in untreated eyes (P<0.001). Angle width of treated eyes increased markedly after LPI, remained stable for 6 months, and then decreased significantly by 18 months after LPI. Untreated eyes experienced a more consistent and rapid decrease in angle width over the same time period. Copyright © 2014 American Academy of Ophthalmology. Published by

The influence of flip angle on the magic angle effect

International Nuclear Information System (INIS)

Zurlo, J.V.; Blacksin, M.F.; Karimi, S.

2000-01-01

Objective. To assess the impact of flip angle with gradient sequences on the ''magic angle effect''. We characterized the magic angle effect in various gradient echo sequences and compared the signal- to-noise ratios present on these sequences with the signal-to-noise ratios of spin echo sequences.Design. Ten normal healthy volunteers were positioned such that the flexor hallucis longus tendon remained at approximately at 55 to the main magnetic field (the magic angle). The tendon was imaged by a conventional spin echo T1- and T2-weighted techniques and by a series of gradient techniques. Gradient sequences were altered by both TE and flip angle. Signal-to-noise measurements were obtained at segments of the flexor hallucis longus tendon demonstrating the magic angle effect to quantify the artifact. Signal-to-noise measurements were compared and statistical analysis performed. Similar measurements were taken of the anterior tibialis tendon as an internal control.Results and conclusions. We demonstrated the magic angle effect on all the gradient sequences. The intensity of the artifact was affected by both the TE and flip angle. Low TE values and a high flip angle demonstrated the greatest magic angle effect. At TE values less than 30 ms, a high flip angle will markedly increase the magic angle effect. (orig.)

Predictors and outcomes of shunt-dependent hydrocephalus in patients with aneurysmal sub-arachnoid hemorrhage

Science.gov (United States)

2012-01-01

Background Hydrocephalus following spontaneous aneurysmal sub-arachnoid hemorrhage (SAH) is often associated with unfavorable outcome. This study aimed to determine the potential risk factors and outcomes of shunt-dependent hydrocephalus in aneurysmal SAH patients but without hydrocephalus upon arrival at the hospital. Methods One hundred and sixty-eight aneurysmal SAH patients were evaluated. Using functional scores, those without hydrocephalus upon arrival at the hospital were compared to those already with hydrocephalus on admission, those who developed it during hospitalization, and those who did not develop it throughout their hospital stay. The Glasgow Coma Score, modified Fisher SAH grade, and World Federation of Neurosurgical Societies grade were determined at the emergency room. Therapeutic outcomes immediately after discharge and 18 months after were assessed using the Glasgow Outcome Score. Results Hydrocephalus accounted for 61.9% (104/168) of all episodes, including 82 with initial hydrocephalus on admission and 22 with subsequent hydrocephalus. Both the presence of intra-ventricular hemorrhage on admission and post-operative intra-cerebral hemorrhage were independently associated with shunt-dependent hydrocephalus in patients without hydrocephalus on admission. After a minimum 1.5 years of follow-up, the mean Glasgow outcome score was 3.33 ± 1.40 for patients with shunt-dependent hydrocephalus and 4.21 ± 1.19 for those without. Conclusions The presence of intra-ventricular hemorrhage, lower mean Glasgow Coma Scale score, and higher mean scores of the modified Fisher SAH and World Federation of Neurosurgical grading on admission imply risk of shunt-dependent hydrocephalus in patients without initial hydrocephalus. These patients have worse short- and long-term outcomes and longer hospitalization. PMID:22765765

[Megadolichobasilar anomaly causing acute deafness with vertigo].

Science.gov (United States)

Unkelbach, M H; Radeloff, A; Bink, A; Gstöttner, W; Ziemann, U

2008-01-01

Megadolichobasilar anomaly, a dilatant arteriopathy of the basilar artery attributable to chronic arterial hypertension, can cause cranial nerve compression syndromes of the cerebellopontine angle or infarcts of the vertebrobasilar circulation. In this paper, we report on a patient with known megadolichobasilar anomaly and a partially thrombosed fusiform aneurysm of the basilar artery, who presented with acute-onset vertigo and subsequent deafness due to thromboembolic occlusion of the labyrinthine artery. Because of the vascular origin of the patient's symptoms, his vertigo disappeared over time while the deafness persisted.

Gas canalography

International Nuclear Information System (INIS)

Portela, L.A.P.

1984-01-01

The advantages and limitations of the cisternography of the cerebello-pontine angle and internal auditory canal, obtained after intrathecal injection of small amount of air (4ml), and the computed tomography, as a simple, sensitive and highly diagnostic procedure, are discussed. The diagnosis of two intracanalicular and cisternal neuromas of less than 10mm in two patients and the safe exclusion of a neuroma in 6 ears of 4 patients are presented. A brief review of the literature is made. (M.A.C.) [pt

The Top 50 Most-Cited Articles on Acoustic Neuroma.

Science.gov (United States)

Alfaifi, Abrar; AlMutairi, Othman; Allhaidan, Maha; Alsaleh, Saad; Ajlan, Abdulrazag

2018-03-01

Acoustic neuroma is the most common extra-axial primary cerebellopontine angle tumor in adults. A plethora of studies have been published on acoustic neuroma, but none of the previous works have highlighted the most influential articles. Our objective was to perform a bibliometric analysis of the 50 most-cited articles on acoustic neuroma. We performed a title-specific search on the Scopus database using the following search terms: "acoustic neuroma," "vestibular schwannoma," and "cerebellopontine angle." We recorded the 50 most-cited articles and reviewed them. The 50 most-cited articles had an average of 175 citations per article. All articles were published between 1980 and 2006, with 1997 the most prolific year, when 7 articles were published. The journals Neurosurgery and Laryngoscope published 10 and 8 of these articles, respectively. The most common study categories were nonsurgical management (17/50) and surgical management (13/50). Studies were predominantly published by otolaryngologists (22/50) and neurosurgeons (14/50). Douglas Kondziolka was the author with the highest number of contributions, with 7 publications. The majority of the articles were produced in the United States (64%). Identifying articles on acoustic neuroma with the most impact provides an important overview of the historical development of treatment methods and publication trends related to this condition. A finalized, comprehensive list of the most important works represents an excellent tool that can serve as a guide for evidence-based clinical practice. Copyright © 2017 Elsevier Inc. All rights reserved.

Longitudinal Changes of Angle Configuration in Primary Angle-Closure Suspects

Science.gov (United States)

Jiang, Yuzhen; Chang, Dolly S.; Zhu, Haogang; Khawaja, Anthony P.; Aung, Tin; Huang, Shengsong; Chen, Qianyun; Munoz, Beatriz; Grossi, Carlota M.

2015-01-01

Objective To determine longitudinal changes in angle configuration in the eyes of primary angle-closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes. Design Longitudinal cohort study. Participants Primary angle-closure suspects aged 50 to 70 years were enrolled in a randomized, controlled clinical trial. Methods Each participant was treated by LPI in 1 randomly selected eye, with the fellow eye serving as a control. Angle width was assessed in a masked fashion using gonioscopy and anterior segment optical coherence tomography (AS-OCT) before and at 2 weeks, 6 months, and 18 months after LPI. Main Outcome Measures Angle width in degrees was calculated from Shaffer grades assessed under static gonioscopy. Angle configuration was also evaluated using angle opening distance (AOD250, AOD500, AOD750), trabecular-iris space area (TISA500, TISA750), and angle recess area (ARA) measured in AS-OCT images. Results No significant difference was found in baseline measures of angle configuration between treated and untreated eyes. At 2 weeks after LPI, the drainage angle on gonioscopy widened from a mean of 13.5° at baseline to a mean of 25.7° in treated eyes, which was also confirmed by significant increases in all AS-OCT angle width measures (Pgonioscopy (P = 0.18), AOD250 (P = 0.167) and ARA (P = 0.83). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared with treated eyes (P values for all variables ≤0.003). The annual rate of change in angle width was equivalent to 1.2°/year (95% confidence interval [CI], 0.8–1.6) in treated eyes and 1.6°/year (95% CI, 1.3–2.0) in untreated eyes (P<0.001). Conclusions Angle width of treated eyes increased markedly after LPI, remained stable for 6 months, and then decreased significantly by 18 months after LPI. Untreated eyes experienced a more consistent and rapid decrease in angle width over the

The paediatric Bohler's angle and crucial angle of Gissane: a case series

Directory of Open Access Journals (Sweden)

Crawford Haemish A

2011-01-01

Full Text Available Abstract Background Bohler's angle and the crucial angle of Gissane can be used to assess calcaneal fractures. While the normal adult values of these angles are widely known, the normal paediatric values have not yet been established. Our aim is to investigate Bohler's angle and the crucial angle of Gissane in a paediatric population and establish normal paediatric reference values. Method We measured Bohler's angle and the crucial angle of Gissane using normal plain ankle radiographs of 763 patients from birth to 14 years of age completed over a five year period from July 2003 to June 2008. Results In our paediatric study group, the mean Bohler's angle was 35.2 degrees and the mean crucial angle of Gissane was 111.3 degrees. In an adult comparison group, the mean Bohler's angle was 39.2 degrees and the mean crucial angle of Gissane was 113.8 degrees. The differences in Bohler's angle and the crucial angle of Gissane between these two groups were statistically significant. Conclusion We have presented the normal values of Bohler's angle and the crucial angle of Gissane in a paediatric population. These values may provide a useful comparison to assist with the management of the paediatric calcaneal fracture.

Creation of the {pi} angle standard for the flat angle measurements

Energy Technology Data Exchange (ETDEWEB)

Giniotis, V; Rybokas, M, E-mail: gi@ap.vtu.l, E-mail: MRybokas@gama.l [Department of Information Technologies, Vilnius Gediminas Technical University, Sauletekio al. 11, 10223 Vilnius-40 (Lithuania)

2010-07-01

Angle measurements are based mainly on multiangle prisms - polygons with autocollimators, rotary encoders for high accuracy and circular scales as the standards of the flat angle. Traceability of angle measurements is based on the standard of the plane angle - prism (polygon) calibrated at an appropriate accuracy. Some metrological institutions have established their special test benches (comparators) equipped with circular scales or rotary encoders of high accuracy and polygons with autocollimators for angle calibration purposes. Nevertheless, the standard (etalon) of plane angle - polygon has many restrictions for the transfer of angle unit - radian (rad) and other units of angle. It depends on the number of angles formed by the flat sides of the polygon that is restricted by technological and metrological difficulties related to the production and accuracy determination of the polygon. A possibility to create the standard of the angle equal to {pi} rad or half the circle or the full angle is proposed. It can be created by the circular scale with the rotation axis of very high accuracy and two precision reading instruments, usually, photoelectric microscopes (PM), placed on the opposite sides of the circular scale using the special alignment steps. A great variety of angle units and values can be measured and its traceability ensured by applying the third PM on the scale. Calibration of the circular scale itself and other scale or rotary encoder as well is possible using the proposed method with an implementation of {pi} rad as the primary standard angle. The method proposed enables to assure a traceability of angle measurements at every laboratory having appropriate environment and reading instruments of appropriate accuracy together with a rotary table with the rotation axis of high accuracy - rotation trajectory (runout) being in the range of 0.05 {mu}m. Short information about the multipurpose angle measurement test bench developed is presented.

Meningitis due to Xanthomonas maltophilia.

Directory of Open Access Journals (Sweden)

Girijaratnakumari T

1993-07-01

Full Text Available During 1st week of post-operative period, a 28 year old female patient operated for left cerebellopontine angle tumor, continued to get fever. Lumbar puncture did not reveal any organisms. She responded to ciprofloxacin. Two months later, she was readmitted with signs and symptoms of meningitis. The CSF tapped on lumbar puncture grew Xanthomonas maltophilia, Gram negative bacilli, sensitive to various antibiotics, ciprofloxacin being one of them. The patient was given ciprofloxacin for 3 weeks. On follow up, a year later she was found to be asymptomatic.

Remote Supratentorial Hemorrhage After Posterior Fossa Surgery: A Brief Case Report

Directory of Open Access Journals (Sweden)

Moscote-Salazar Luis Rafael

2014-10-01

Full Text Available The supratentorial hemorrhage after posterior fossa surgery is an unusual but delicate complication that carries high mortality and morbidity. A 50 year old woman presented vertigo 6 months of evolution, which worsened in the last 2 months accompanied by ataxia. She showed left cerebellar signs, had no focal motor or sensory deficits. A brain MRI identified cerebellopontine angle lesion with mass effect. The patient was treated on suboccipital craniectomy and resection of right posterior fossa tumor, the histopathological diagnosis was consistent with typical meningioma. (WHO Class I.

Glaucoma, Open-Angle

Science.gov (United States)

... Home » Statistics and Data » Glaucoma, Open-angle Listen Glaucoma, Open-angle Open-angle Glaucoma Defined In open-angle glaucoma, the fluid passes ... 2010 2010 U.S. Age-Specific Prevalence Rates for Glaucoma by Age and Race/Ethnicity The prevalence of ...

Introduction: surgical management of skull base meningiomas.

Science.gov (United States)

Zada, Gabriel; Başkaya, Mustafa K; Shah, Mitesh V

2017-10-01

Meningiomas represent the most common primary intracranial neoplasm treated by neurosurgeons. Although multimodal treatment of meningiomas includes surgery, radiation-based treatments, and occasionally medical therapy, surgery remains the mainstay of treatment for most symptomatic meningiomas. Because of the intricate relationship of the dura mater and arachnoid mater with the central nervous system and cranial nerves, meningiomas can arise anywhere along the skull base or convexities, and occasionally even within the ventricular system, thereby mandating a catalog of surgical approaches that neurosurgeons may employ to individualize treatment for patients. Skull base meningiomas represent some of the most challenging pathology encountered by neurosurgeons, on account of their depth, invasion, vascularity, texture/consistency, and their relationship to bony anatomy, cranial nerves, and blood vessels. Resection of complex skull base meningiomas often mandates adequate bony removal to achieve sufficient exposure of the tumor and surrounding region, in order to minimize brain retraction and optimally identify, protect, control, and manipulate sensitive neurovascular structures. A variety of traditional skull base approaches has evolved to address complex skull base tumors, of which meningiomas are considered the paragon in terms of both complexity and frequency. In this supplemental video issue of Neurosurgical Focus, contributing authors from around the world provide instructional narratives demonstrating resection of a variety of skull base meningiomas arising from traditionally challenging origins, including the clinoid processes, tuberculum sellae, dorsum sellae, petroclival region, falco-tentorial region, cerebellopontine angle, and foramen magnum. In addition, two cases of extended endoscopic endonasal approaches for tuberculum sellae and dorsum sellae meningiomas are presented, representing the latest evolution in accessing the skull base for selected tumors

Timing of births in sympatric brown howler monkeys (Alouatta fusca clamitans) and northern muriquis (Brachyteles arachnoides hypoxanthus).

Science.gov (United States)

Strier, K B; Mendes, S L; Santos, R R

2001-10-01

We monitored the birth patterns of sympatric brown howler monkeys (Alouatta fusca clamitans) and northern muriquis (Brachyteles arachnoides hypoxanthus) during a 4-yr period from October 1996 to August 2000 at the Estação Biológica de Caratinga, Minas Gerais, Brazil. Brown howler monkey births (n = 34) occurred throughout the year, and birth frequencies did not differ between rainy and dry season months. The aseasonal birth patterns of the howler monkeys differed significantly from the dry season concentration and dry month peak in muriqui births (n = 23). We found no effects of infant sex or the number of females on interbirth intervals (IBIs) in our 10 howler monkey study troops. IBIs of brown howler monkeys averaged 21.2 +/- 2.5 mo (n = 8, median = 21.0 mo), and were significantly shorter following dry season births than rainy season births. Their IBIs and yearling survivorship (74%) were similar to those reported for other species of howler monkeys, but yearling survivorship was much lower than that of muriquis (94%), whose IBIs were more than 12 mo longer than those of the howler monkeys. Our study extends comparative knowledge of birth patterns in Alouatta to a poorly known species, and provides insights into the different ways in which diet and life history may affect the timing of births in large-bodied platyrrhines under the same seasonal ecological conditions. Copyright 2001 Wiley-Liss, Inc.

Apparent contact angle and contact angle hysteresis on liquid infused surfaces.

Science.gov (United States)

Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

2016-12-21

We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as 'weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

Estimates of md-mu and left-angle bar dd right-angle -left-angle bar uu right-angle from QCD sum rules for D and D* isospin mass differences

International Nuclear Information System (INIS)

Eletsky, V.L.; Ioffe, B.L.

1993-01-01

The recent experimental data on D +- D0 and D *+- D*0 mass differences are used as inputs in the QCD sum rules to obtain new estimates on the mass difference of light quarks and on the difference of their condensates: m d -m u =3±1 MeV, left-angle bar dd right-angle -left-angle bar uu right-angle=-(2.5±1)x10 -3 left-angle bar uu right-angle (at a standard normalization point, μ=0.5 GeV)

Scoliosis angle

International Nuclear Information System (INIS)

Marklund, T.

1978-01-01

The most commonly used methods of assessing the scoliotic deviation measure angles that are not clearly defined in relation to the anatomy of the patient. In order to give an anatomic basis for such measurements it is proposed to define the scoliotic deviation as the deviation the vertebral column makes with the sagittal plane. Both the Cobb and the Ferguson angles may be based on this definition. The present methods of measurement are then attempts to measure these angles. If the plane of these angles is parallel to the film, the measurement will be correct. Errors in the measurements may be incurred by the projection. A hypothetical projection, called a 'rectified orthogonal projection', is presented, which correctly represents all scoliotic angles in accordance with these principles. It can be constructed in practice with the aid of a computer and by performing measurements on two projections of the vertebral column; a scoliotic curve can be represented independent of the kyphosis and lordosis. (Auth.)

Automated analysis of angle closure from anterior chamber angle images.

Science.gov (United States)

Baskaran, Mani; Cheng, Jun; Perera, Shamira A; Tun, Tin A; Liu, Jiang; Aung, Tin

2014-10-21

To evaluate a novel software capable of automatically grading angle closure on EyeCam angle images in comparison with manual grading of images, with gonioscopy as the reference standard. In this hospital-based, prospective study, subjects underwent gonioscopy by a single observer, and EyeCam imaging by a different operator. The anterior chamber angle in a quadrant was classified as closed if the posterior trabecular meshwork could not be seen. An eye was classified as having angle closure if there were two or more quadrants of closure. Automated grading of the angle images was performed using customized software. Agreement between the methods was ascertained by κ statistic and comparison of area under receiver operating characteristic curves (AUC). One hundred forty subjects (140 eyes) were included, most of whom were Chinese (102/140, 72.9%) and women (72/140, 51.5%). Angle closure was detected in 61 eyes (43.6%) with gonioscopy in comparison with 59 eyes (42.1%, P = 0.73) using manual grading, and 67 eyes (47.9%, P = 0.24) with automated grading of EyeCam images. The agreement for angle closure diagnosis between gonioscopy and both manual (κ = 0.88; 95% confidence interval [CI), 0.81-0.96) and automated grading of EyeCam images was good (κ = 0.74; 95% CI, 0.63-0.85). The AUC for detecting eyes with gonioscopic angle closure was comparable for manual and automated grading (AUC 0.974 vs. 0.954, P = 0.31) of EyeCam images. Customized software for automated grading of EyeCam angle images was found to have good agreement with gonioscopy. Human observation of the EyeCam images may still be needed to avoid gross misclassification, especially in eyes with extensive angle closure. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

部分肌松下多组颅神经监护在小脑桥脑角区肿瘤切除术患者中的应用%Intraoperative cranial nerves monitoring under partial neuromuscular relaxation during cerebellopontine angle tumor resection

Institute of Scientific and Technical Information of China (English)

张军; 杨程; 顾华华; 梁伟民

2008-01-01

Objective To evaluate the efficacy of multiple cranial nerves monitoring under partial neuromuscular relaxation during cerebellopontine angle(CPA)tumor resection.Methods Seventy elective patients undergoing CPA tumor resection via microneurosurgery were randomly allocated to 2 equal groups: Group FN receiving intraoperative facial nerve(NF)monitoring and Group MN receiving monitoring of multiple nerves:trigeminal nerve,glossopharyngeal nerve,accessory nerve or hypoglossal nerve other than the FN which were considered at risk by the neurosurgeon preoperatively.The manipulation procedure were modified according to cranial nerves monitoring and neuromuscular relaxation was maintained at train of four stimulation(TOF)=3 by continuous vencronium infusion during the acoustic neuroma resection.The function of the cranial nerves monitored were evaluated preoperatively and 8 days postoperativelv.Results Discernable and legible images of electromyographic wave complex were obtained during cranial nerve mapping and monitoring under intraoperative partial neuromuscular relaxation form all the patients.The facial nerve function of 4 patients exacerbated(from H-B grade Ⅰ-Ⅱ to gradeⅢ-Ⅳ)in both groups,and one new glossopharyngeal nerve function deficiency was found in Group FN,and one new hypoglossal nerve function deficiency was found in Group MN postoperatively.Conclusion Intraoperative cranial nenves monitoring under partial neuromuscular relaxation is feasible.Multiple cranial nerves combined with facial nerve monitoring seems unable to increase the short-term protective effects of nerve function after CPA tumor resection.%目的 评价全身麻醉下小脑桥脑角区肿瘤切除术患者中,在部分肌松条件下多组颅神经监护的效率.方法 70例择期行小脑桥脑角区肿瘤显微手术患者,随机分为两组,一组术中只进行面神经监护(FN组,n=35),�

Multimodal Image-Based Virtual Reality Presurgical Simulation and Evaluation for Trigeminal Neuralgia and Hemifacial Spasm.

Science.gov (United States)

Yao, Shujing; Zhang, Jiashu; Zhao, Yining; Hou, Yuanzheng; Xu, Xinghua; Zhang, Zhizhong; Kikinis, Ron; Chen, Xiaolei

2018-05-01

To address the feasibility and predictive value of multimodal image-based virtual reality in detecting and assessing features of neurovascular confliction (NVC), particularly regarding the detection of offending vessels, degree of compression exerted on the nerve root, in patients who underwent microvascular decompression for nonlesional trigeminal neuralgia and hemifacial spasm (HFS). This prospective study includes 42 consecutive patients who underwent microvascular decompression for classic primary trigeminal neuralgia or HFS. All patients underwent preoperative 1.5-T magnetic resonance imaging (MRI) with T2-weighted three-dimensional (3D) sampling perfection with application-optimized contrasts by using different flip angle evolutions, 3D time-of-flight magnetic resonance angiography, and 3D T1-weighted gadolinium-enhanced sequences in combination, whereas 2 patients underwent extra experimental preoperative 7.0-T MRI scans with the same imaging protocol. Multimodal MRIs were then coregistered with open-source software 3D Slicer, followed by 3D image reconstruction to generate virtual reality (VR) images for detection of possible NVC in the cerebellopontine angle. Evaluations were performed by 2 reviewers and compared with the intraoperative findings. For detection of NVC, multimodal image-based VR sensitivity was 97.6% (40/41) and specificity was 100% (1/1). Compared with the intraoperative findings, the κ coefficients for predicting the offending vessel and the degree of compression were >0.75 (P < 0.001). The 7.0-T scans have a clearer view of vessels in the cerebellopontine angle, which may have significant impact on detection of small-caliber offending vessels with relatively slow flow speed in cases of HFS. Multimodal image-based VR using 3D sampling perfection with application-optimized contrasts by using different flip angle evolutions in combination with 3D time-of-flight magnetic resonance angiography sequences proved to be reliable in detecting NVC

Herniation of the cerebellar tonsils after suprasellar arachnoid cyst shunt: case report Herniação das tonsilas cerebelares após shunt de cisto aracnóide supra-selar: relato de caso

Directory of Open Access Journals (Sweden)

Rodrigo Mendonça

2006-06-01

Full Text Available It is known that the caudal dislocation of the cerebellar tonsils may occur associated with clinical conditions such as an intracranial mass lesion or Chiari I and II malformation. It may also be acquired after repeated lumbar punctures or lumboperitoneostomy. The occurrence of cerebellar herniation after derivation of intracranial arachnoid cyst is extremely rare, and there are only three cases reported in the medical literature. We present the case of a 9-year-old boy with precocious puberty and suprasellar arachnoid cyst who developed a symptomatic herniation of the cerebellar tonsils three years after a cystoperitoneostomy. The patient underwent a suboccipital craniectomy with duraplasty and partial tonsilectomy, showing afterwards, remission of the symptoms. We discussed the pathogenesis suggested in the literature.Sabe-se que o deslocamento caudal das tonsilas cerebelares pode ocorrer em associação com condições clínicas tais como: lesão expansiva intracraniana ou malformação de Chiari I e II. Pode ainda ser adquirido após repetidas punções lombares ou lomboperitoniostomia. A ocorrência de herniação cerebelar após derivação de cisto aracnóide intracraniano é evento extremamente raro, existindo apenas três casos relatados na literatura médica. O caso de menino de 9 anos de idade, com puberdade precoce e cisto aracnóide supra-selar, que desenvolveu herniação sintomática das tonsilas cerebelares três anos após cistoperitoniostomia. O paciente foi submetido a craniectomia suboccipital com plástica dural e tonsilectomia parcial, apresentando remissão dos sintomas. Discutimos a patogênese sugerida na literatura.

Optimal reconstruction angles

International Nuclear Information System (INIS)

Cook, G.O. Jr.; Knight, L.

1979-07-01

The question of optimal projection angles has recently become of interest in the field of reconstruction from projections. Here, studies are concentrated on the n x n pixel space, where literative algorithms such as ART and direct matrix techniques due to Katz are considered. The best angles are determined in a Gauss--Markov statistical sense as well as with respect to a function-theoretical error bound. The possibility of making photon intensity a function of angle is also examined. Finally, the best angles to use in an ART-like algorithm are studied. A certain set of unequally spaced angles was found to be preferred in several contexts. 15 figures, 6 tables

Microsurgical and Endoscopic Anatomy for Intradural Temporal Bone Drilling and Applications of the Electromagnetic Navigation System: Various Extensions of the Retrosigmoid Approach.

Science.gov (United States)

Matsushima, Ken; Komune, Noritaka; Matsuo, Satoshi; Kohno, Michihiro

2017-07-01

The use of the retrosigmoid approach has recently been expanded by several modifications, including the suprameatal, transmeatal, suprajugular, and inframeatal extensions. Intradural temporal bone drilling without damaging vital structures inside or beside the bone, such as the internal carotid artery and jugular bulb, is a key step for these extensions. This study aimed to examine the microsurgical and endoscopic anatomy of the extensions of the retrosigmoid approach and to evaluate the clinical feasibility of an electromagnetic navigation system during intradural temporal bone drilling. Five temporal bones and 8 cadaveric cerebellopontine angles were examined to clarify the anatomy of retrosigmoid intradural temporal bone drilling. Twenty additional cerebellopontine angles were dissected in a clinical setting with an electromagnetic navigation system while measuring the target registration errors at 8 surgical landmarks on and inside the temporal bone. Retrosigmoid intradural temporal bone drilling expanded the surgical exposure to allow access to the petroclival and parasellar regions (suprameatal), internal acoustic meatus (transmeatal), upper jugular foramen (suprajugular), and petrous apex (inframeatal). The electromagnetic navigation continuously guided the drilling without line of sight limitation, and its small devices were easily manipulated in the deep and narrow surgical field in the posterior fossa. Mean target registration error was less than 0.50 mm during these procedures. The combination of endoscopic and microsurgical techniques aids in achieving optimal exposure for retrosigmoid intradural temporal bone drilling. The electromagnetic navigation system had clear advantages with acceptable accuracy including the usability of small devices without line of sight limitation. Copyright © 2017 Elsevier Inc. All rights reserved.

Cerebellar clear cell ependymoma in a 10 year old girl

Energy Technology Data Exchange (ETDEWEB)

Thinzar Aye Nyein; Moon, Ah Rim; Hwang, Sun Chul; Hong, Hyun Sook; Lee, A Leum; Chang, Kee Hyun; Kim, Hee Kyung; Chin, Su Sie [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of); Park, Ji Sang [Soonchunhyang University Gumi Hospital, Gumi (Korea, Republic of)

2016-01-15

Clear cell ependymoma (CCE) is a histological rare variant (1–5%) of ependymoma, which is distinguished from other histological subtypes by the presence of fusiform cells arrayed radially around small blood vessels. These alleged perivascular pseudorosettes are significant characteristic features of ependymomas. About 95% of infratentorial ependymomas are found in the fourth ventricle and the remainder occurs as cerebellopontine angle lesions. In previous reports, the cerebellum is found to be a rare location for ependymoma. In this study we report one case of CCE originating from the cerebellar hemisphere, showing unusual morphology on 3T MRI.

Apparent Contact Angle and Contact Angle Hysteresis on Liquid Infused Surfaces

OpenAIRE

Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

2016-01-01

We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small b...

Undetected angle closure in patients with a diagnosis of open-angle glaucoma.

Science.gov (United States)

Varma, Devesh K; Simpson, Sarah M; Rai, Amandeep S; Ahmed, Iqbal Ike K

2017-08-01

The aim of this study was to identify the proportion of patients referred to a tertiary glaucoma centre with a diagnosis of open-angle glaucoma (OAG) who were found to have angle closure glaucoma. Retrospective chart review. Consecutive new patients referred for glaucoma management to a tertiary centre between July 2010 and December 2011 were reviewed. Patients whose referrals for glaucoma assessment specified angle status as "open" were included. The data collected included glaucoma specialist's angle assessment, diagnosis, and glaucoma severity. The status of those with 180 degrees or more Shaffer angle grading of 0 was classified as "closed." From 1234 glaucoma referrals, 179 cases were specified to have a diagnosis of OAG or when angles were known to be open. Of these, 16 (8.9%) were found on examination by the glaucoma specialist to have angle closure. Pseudoexfoliation was present in 4 of 16 patients (25%) in the missed angle-closure glaucoma (ACG) group and 22 of 108 patients (13.5%) in the remaining OAG group. There was no difference found in demographic or ocular biometric parameters between those with confirmed OAG versus those with missed ACG. Almost 1 in 11 patients referred by ophthalmologists to a tertiary glaucoma centre with a diagnosis of OAG were in fact found to have angle closure. Given the different treatment approaches for ACG versus OAG, this study suggests a need to strengthen angle evaluations. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Evaluation of blotchy pigments in the anterior chamber angle as a sign of angle closure

Directory of Open Access Journals (Sweden)

Harsha L Rao

2012-01-01

Full Text Available Background: Blotchy pigments in the anterior chamber (AC angle are considered diagnostic of primary angle closure (PAC. But there are no reports either on the prevalence of blotchy pigments in AC angles or the validity of this sign. Aims: To determine the prevalence of blotchy pigments in AC angles and to evaluate their relationship with glaucomatous optic neuropathy (GON in eyes with occludable angles. Setting and Design: Cross-sectional, comparative study. Materials and Methods: Gonioscopy was performed in 1001 eyes of 526 subjects (245 eyes of 148 consecutive, occludable angle subjects and 756 eyes of 378 non-consecutive, open angle subjects, above 35 years of age. Quadrant-wise location of blotchy pigments was documented. Statistical Analysis: Odds of blotchy pigments in occludable angles against that in open angles were evaluated. Relationship of GON with blotchy pigments in occludable angle eyes was evaluated using a multivariate model. Results: Prevalence of blotchy pigments in occludable angles was 28.6% (95% CI, 22.9-34.3 and in open angles was 4.7% (95% CI, 3.2-6.3. Blotchy pigments were more frequently seen in inferior (16% and superior quadrants (15% of occludable angles, and inferior quadrant of open angles (4%. Odds of superior quadrant blotchy pigments in occludable angles were 33 times that in open angles. GON was seen in 107 occludable angle eyes. Blotchy pigments were not significantly associated with GON (odds ratio = 0.5; P = 0.1. Conclusions: Blotchy pigments were seen in 28.6% of occludable angle eyes and 4.7% of open angles eyes. Presence of blotchy pigments in the superior quadrant is more common in occludable angles. Presence of GON in occludable angle eyes was not associated with blotchy pigments.

Evaluation of blotchy pigments in the anterior chamber angle as a sign of angle closure

Science.gov (United States)

Rao, Harsha L; Mungale, Sachin C; Kumbar, Tukaram; Parikh, Rajul S; Garudadri, Chandra S

2012-01-01

Background: Blotchy pigments in the anterior chamber (AC) angle are considered diagnostic of primary angle closure (PAC). But there are no reports either on the prevalence of blotchy pigments in AC angles or the validity of this sign. Aims: To determine the prevalence of blotchy pigments in AC angles and to evaluate their relationship with glaucomatous optic neuropathy (GON) in eyes with occludable angles. Setting and Design: Cross-sectional, comparative study. Materials and Methods: Gonioscopy was performed in 1001 eyes of 526 subjects (245 eyes of 148 consecutive, occludable angle subjects and 756 eyes of 378 non-consecutive, open angle subjects), above 35 years of age. Quadrant-wise location of blotchy pigments was documented. Statistical Analysis: Odds of blotchy pigments in occludable angles against that in open angles were evaluated. Relationship of GON with blotchy pigments in occludable angle eyes was evaluated using a multivariate model. Results: Prevalence of blotchy pigments in occludable angles was 28.6% (95% CI, 22.9-34.3) and in open angles was 4.7% (95% CI, 3.2-6.3). Blotchy pigments were more frequently seen in inferior (16%) and superior quadrants (15%) of occludable angles, and inferior quadrant of open angles (4%). Odds of superior quadrant blotchy pigments in occludable angles were 33 times that in open angles. GON was seen in 107 occludable angle eyes. Blotchy pigments were not significantly associated with GON (odds ratio = 0.5; P = 0.1). Conclusions: Blotchy pigments were seen in 28.6% of occludable angle eyes and 4.7% of open angles eyes. Presence of blotchy pigments in the superior quadrant is more common in occludable angles. Presence of GON in occludable angle eyes was not associated with blotchy pigments. PMID:23202393

Low-Cost Interactive Image-Based Virtual Endoscopy for the Diagnosis and Surgical Planning of Suprasellar Arachnoid Cysts.

Science.gov (United States)

Li, Ye; Zhao, Yining; Zhang, Jiashu; Zhang, Zhizhong; Dong, Guojun; Wang, Qun; Liu, Lei; Yu, Xinguang; Xu, Bainan; Chen, Xiaolei

2016-04-01

To investigate the feasibility and reliability of virtual endoscopy (VE) as a rapid, low-cost, and interactive tool for the diagnosis and surgical planning of suprasellar arachnoid cysts (SACs). Eighteen patients with SACs treated with endoscopic ventriculocystostomy were recruited, and 18 endoscopic patients treated with third ventriculostomy were randomly selected as a VE reconstruction control group. After loading their DICOM data into free 3D Slicer software, VE reconstruction was independently performed by 3 blinded clinicians and the time required for each reconstruction was recorded. Another 3 blinded senior neurosurgeons interactively graded the visibility of VE by watching video recordings of the endoscopic procedures. Based on the visibility scores, receiver operating characteristic curve analysis was used to investigate the reliability of VE to diagnose SACs, and Bland-Altman plots were used to assess the reliability of VE for surgical planning. In addition, the intraclass correlation coefficient was calculated to estimate the consistency among the results of 3 reconstruction performers. All 3 independent reconstructing performers successfully completed VE simulation for all cases, and the average reconstruction time was 10.2 ± 9.7 minutes. The area under the receiver operating characteristic curve of the cyst visibility score was 0.96, implying its diagnostic value for SACs. The Bland-Altman plot indicated good agreement between VE and intraoperative viewings, suggesting the anatomic accuracy of the VE for surgical planning. In addition, the intraclass correlation coefficient was 0.81, which revealed excellent interperformer consistency of our simulation method. This study substantiated the feasibility and reliability of VE as a rapid, low-cost, and interactive modality for diagnosis and surgical planning of SACs. Copyright © 2016 Elsevier Inc. All rights reserved.

The Q-angle and sport

DEFF Research Database (Denmark)

Hahn, Thomas; Foldspang, Anders

1997-01-01

Quadriceps muscle contraction tends to straighten the Q angle. We expected that sports comprising a high amount of quadriceps training could be associated with low Q angles. The aim of the present study was to estimate the Q angle in athletes and to investigate its potential associations with par......Quadriceps muscle contraction tends to straighten the Q angle. We expected that sports comprising a high amount of quadriceps training could be associated with low Q angles. The aim of the present study was to estimate the Q angle in athletes and to investigate its potential associations...... with participation in sport. Three hundred and thirty-nine athletes had their Q angle measured. The mean of right-side Q angles was higher than left side, and the mean Q angle was higher in women than in men. The Q angle was positively associated with years of jogging, and negatively with years of soccer, swimming...... and sports participation at all. It is concluded that the use of Q angle measurements is questionable....

Contact Angle Goniometer

Data.gov (United States)

Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

left-angle 100 right-angle Burgers vector in single phase γ' material verified by image simulation

International Nuclear Information System (INIS)

Link, T.; Knobloch, C.; Glatzel, U.

1998-01-01

The deformation mechanisms of Ni 3 Al, an ordered L1 2 or γ' phase, is under intense research since Westbrook showed the increase of its hardness with temperature in 1957. The super dislocations of this ordered phase normally have Burgers vectors rvec b = a left-angle 110 right-angle, disassociated in either two a/2 left-angle 110 right-angle or two rvec b = a/3 left-angle 112 right-angle, depending on deformation temperature and rate. Recent observations in [111] oriented γ' specimens suggest that additional dislocations with the shorter Burgers vector rvec b = a left-angle 100 right-angle might be active. Dislocations with rvec b = a left-angle 110 right-angle on cube glide planes have a Schmidt factor of 0.47 and on octahedral planes of 0.27. Dislocations with rvec b = a left-angle 100 right-angle have a Schmidt factor of 0.47 for {110} glide planes and 0.33 for cube glide planes. The a left-angle 100 right-angle Burgers vector is the shortest of all complete dislocations of the L1 2 structure and creates no planar fault like antiphase boundaries or stacking faults. Due to the [111] oriented stress axis, which is used in this contribution, plastic deformation by a left-angle 100 right-angle dislocations as well as cube glide planes for left-angle 110 right-angle dislocations is encouraged. These dislocations could be reaction products, but will soon after contribute to deformation

Outcomes of Direct Facial-to-Hypoglossal Neurorrhaphy with Parotid Release.

Science.gov (United States)

Jacobson, Joel; Rihani, Jordan; Lin, Karen; Miller, Phillip J; Roland, J Thomas

2011-01-01

Lesions of the temporal bone and cerebellopontine angle and their management can result in facial nerve paralysis. When the nerve deficit is not amenable to primary end-to-end repair or interpositional grafting, nerve transposition can be used to accomplish the goals of restoring facial tone, symmetry, and voluntary movement. The most widely used nerve transposition is the hypoglossal-facial nerve anastamosis, of which there are several technical variations. Previously we described a technique of single end-to-side anastamosis using intratemporal facial nerve mobilization and parotid release. This study further characterizes the results of this technique with a larger patient cohort and longer-term follow-up. The design of this study is a retrospective chart review and the setting is an academic tertiary care referral center. Twenty-one patients with facial nerve paralysis from proximal nerve injury at the cerebellopontine angle underwent facial-hypoglossal neurorraphy with parotid release. Outcomes were assessed using the Repaired Facial Nerve Recovery Scale, questionnaires, and patient photographs. Of the 21 patients, 18 were successfully reinnervated to a score of a B or C on the recovery scale, which equates to good oral and ocular sphincter closure with minimal mass movement. The mean duration of paralysis between injury and repair was 12.1 months (range 0 to 36 months) with a mean follow-up of 55 months. There were no cases of hemiglossal atrophy, paralysis, or subjective dysfunction. Direct facial-hypoglossal neurorrhaphy with parotid release achieved a functional reinnervation and good clinical outcome in the majority of patients, with minimal lingual morbidity. This technique is a viable option for facial reanimation and should be strongly considered as a surgical option for the paralyzed face.

Angle Performance on Optima XE

International Nuclear Information System (INIS)

David, Jonathan; Satoh, Shu

2011-01-01

Angle control on high energy implanters is important due to shrinking device dimensions, and sensitivity to channeling at high beam energies. On Optima XE, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through a series of narrow slits, and any angle adjustment is made by steering the beam with the corrector magnet. In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen during implant.Using a sensitive channeling condition, we were able to quantify the angle repeatability of Optima XE. By quantifying the sheet resistance sensitivity to both horizontal and vertical angle variation, the total angle variation was calculated as 0.04 deg. (1σ). Implants were run over a five week period, with all of the wafers selected from a single boule, in order to control for any crystal cut variation.

The Management of Refractory Dry Eye With Semi-Scleral Contact Lens.

Science.gov (United States)

Yuksel, Erdem; Bilgihan, Kamil; Novruzlu, Şahin; Yuksel, Nilay; Koksal, Murat

2016-05-19

We presented a case of refractory dry eye management with semi-scleral contact lens. Dry eye was associated with facial nerve (cranial nerve VII) palsy as a result of cerebellopontine angle tumor surgery. She was treated with several topical treatments and punctal plug. Despite the treatments, her symptoms still persisted. Her ophthalmic examination revealed scleral exposure because of lagophthalmos, conjunctival hyperemia, corneal debris, scar, and diffuse punctate epitheliopathy on her right eye. Lissamine green staining showed diffuse conjunctival and corneal staining. Therapeutic semi-scleral lenses were fitted. The corneal findings were resolved and the quality of patient life was improved with the aid of semi-scleral lens after 3 months.

Small angle neutron scattering and small angle X-ray scattering ...

Indian Academy of Sciences (India)

Abstract. The morphology of carbon nanofoam samples comprising platinum nanopar- ticles dispersed in the matrix was characterized by small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) techniques. Results show that the structure of pores of carbon matrix exhibits a mass (pore) fractal nature ...

Sharper angle, higher risk? The effect of cutting angle on knee mechanics in invasion sport athletes.

Science.gov (United States)

Schreurs, Mervin J; Benjaminse, Anne; Lemmink, Koen A P M

2017-10-03

Cutting is an important skill in team-sports, but unfortunately is also related to non-contact ACL injuries. The purpose was to examine knee kinetics and kinematics at different cutting angles. 13 males and 16 females performed cuts at different angles (45°, 90°, 135° and 180°) at maximum speed. 3D kinematics and kinetics were collected. To determine differences across cutting angles (45°, 90°, 135° and 180°) and sex (female, male), a 4×2 repeated measures ANOVA was conducted followed by post hoc comparisons (Bonferroni) with alpha level set at α≤0.05a priori. At all cutting angles, males showed greater knee flexion angles than females (pcutting angles with no differences in the amount of knee flexion -42.53°±8.95°, females decreased their knee flexion angle from -40.6°±7.2° when cutting at 45° to -36.81°±9.10° when cutting at 90°, 135° and 180° (pcutting towards sharper angles (pcutting angles and then stabilized compared to the 45° cutting angle (pcutting to sharper angles (pcutting angles demand different knee kinematics and kinetics. Sharper cutting angles place the knee more at risk. However, females and males handle this differently, which has implications for injury prevention. Copyright © 2017 Elsevier Ltd. All rights reserved.

Survival and Growth of Cottonwood Clones After Angle Planting and Base Angle Treatments

Science.gov (United States)

W.K. Randall; Harvey E. Kennedy

1976-01-01

Presently, commercial cottonwood plantations in the lower Mississippi Valley are established using vertically planted, unrooted cuttings with a flat (90°) base. Neither survival nor first-year growth of a group of six Stoneville clones was improved by angle planting or cutting base angles diagonally. For one clone, survival was significantly better when base angle was...

The double Brewster angle effect

Science.gov (United States)

Thirion-Lefevre, Laetitia; Guinvarc'h, Régis

2018-01-01

The Double Brewster angle effect (DBE) is an extension of the Brewster angle to double reflection on two orthogonal dielectric surfaces. It results from the combination of two pseudo-Brewster angles occurring in complementary incidence angles domains. It can be observed for a large range of incidence angles provided that double bounces mechanism is present. As a consequence of this effect, we show that the reflection coefficient at VV polarization can be at least 10 dB lower than the reflection coefficient at HH polarization over a wide range of incidence angle - typically from 20 to 70∘. It is experimentally demonstrated using a Synthetic Aperture Radar (SAR) image that this effect can be seen on buildings and forests. For large buildings, the difference can reach more than 20 dB. xml:lang="fr"

Prospective case series on trabecular-iris angle status after an acute episode of phacomorphic angle closure

Directory of Open Access Journals (Sweden)

Jacky Lee

2013-02-01

Full Text Available AIM:To investigate the trabecular-iris angle with ultrasound biomicroscopy (UBM post cataract extraction after an acute attack of phacomorphic angle closure.METHODS: This prospective study involved 10 cases of phacomorphic angle closure that underwent cataract extraction and intraocular lens insertion after intraocular pressure (IOP lowering. Apart from visual acuity and IOP, the trabecular-iris angle was measured by gonioscopy and UBM at 3 months post attack.RESULTS: In 10 consecutive cases of acute phacomorphic angle closure from December 2009 to December 2010, gonioscopic findings showed peripheral anterior synechiae (PAS ≤ 90° in 30% of phacomorphic patients and a mean Shaffer grading of (3.1±1.0. UBM showed a mean angle of (37.1°±4.5° in the phacomorphic eye with the temporal quadrant being the most opened and (37.1°±8.0° in the contralateral uninvolved eye. The mean time from consultation to cataract extraction was (1.4±0.7 days and the mean total duration of phacomorphic angle closure was (3.6±2.8 days but there was no correlation to the degree of angle closure on UBM (Spearman correlation P=0.7. The presenting mean IOP was (50.5±7.4 mmHg and the mean IOP at 3 months was (10.5±3.4 mmHg but there were no correlations with the degree of angle closure (Spearman correlations P=0.9.CONCLUSION:An open trabecular-iris angle and normal IOP can be achieved after an acute attack of phacomorphic angle closure if cataract extraction is performed within 1 day - 2 days after IOP control. Gonioscopic findings were in agreement with UBM, which provided a more specific and object angle measurement. The superior angle is relatively more narrowed compared to the other quadrants. All contralateral eyes in this series had open angles.

Phacoemulsification with intraocular lens implantation in primary angle-closure suspect, primary angle-closure and primary angle-closure glaucoma with cataract

Directory of Open Access Journals (Sweden)

Kun Zeng

2013-08-01

Full Text Available AIM: To evaluate the features and clinical outcomes of cataract extraction by phacoemulsification with intraocular lens implantation in primary angle-closure suspect(PACS, primary angle-closure(PACand primary angle-closure glaucoma(PACGwith cataract.METHODS:Phacoemulsification with intraocular lens implantation was performed on 86 cases(86 eyesdiagnosed as PACS, PAC and PACG co-existing cataract from January to December 2012. All cases were followed up for 3 months to 1 year. Pre-operative and post-operative visual acuity, intraocular pressure(IOP, gonioscopy, ultrasound biomicroscopy(UBM, visual field and usage of anti-glaucomaous eye drops were recorded.RESULTS:Zonular dialysis existed in 19 eyes(22%. The post-operative visual acuity improved in 84 eyes(98%. The post-operative visual acuity was CONCLUSION: PACS, PAC and PACG co-existing zonular dialysis is common. Phacoemulsification with IOL implantation can reduce IOP, deepen anterior chamber and open angle.

Histological-subtypes and anatomical location correlated in meningeal brain tumors (meningiomas

Directory of Open Access Journals (Sweden)

Abdul Rashid Bhat

2014-01-01

Full Text Available Context: Not enough literature is available to suggest a link between the histological subtypes of intracranial meningeal brain tumors, called ′meningiomas′ and their location of origin. Aim: The evidence of correlation between the anatomical location of the intracranial meningiomas and the histopathological grades will facilitate specific diagnosis and accurate treatment. Materials and Methods: The retrospective study was conducted in a single high-patient-inflow Neurosurgical Center, under a standard and uniform medical protocol, over a period of 30 years from December 1982 to December 2012. The records of all the operated 729 meningiomas were analyzed from the patient files in the Medical Records Department. The biodata, x-rays, angiography, computed tomography (CT scans, imaging, histopathological reports, and mortality were evaluated and results drawn. Results: The uncommon histopathological types of meningiomas (16.88% had common locations of origin in the sphenoid ridge, posterior parafalcine, jugular foramen, peritorcular and intraventricular regions, cerebellopontine angle, and tentorial and petroclival areas. The histopathological World Health Organization (WHO Grade I (Benign Type meningiomas were noted in 89.30%, WHO Grade II (Atypical Type in 5.90%, and WHO Grade III (Malignant Type in 4.80% of all meningiomas. Meningiomas of 64.60% were found in females, 47.32% were in the age group of 41-50 years, and 3.43% meningiomas were found in children. An overall mortality of 6.04% was noted. WHO Grade III (malignant meningiomas carried a high mortality (25.71% and the most common sites of meningiomas with high mortality were: The cerebellopontine angles, intraventricular region, sphenoid ridge, tuberculum sellae, and the posterior parafalcine areas. Conclusion: The correlation between the histological subtypes and the anatomical location of intracranial meningeal brain tumors, called meningiomas, is evident, but further research is

CISS MR imaging findings of epidermoid tumor : comparison with spin-echo images

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Woo; Kim, Hak Jin; Choi, Sang Yoel; Heo, Jin Sam; Jung, Hoon Sik; Lee, Suck Hong; Kim, Byung Soo [Pusan National Univ. College of Medicine, Pusan (Korea, Republic of); Lee, Jong Wha [Ulsan Univ. Hospital, Ulsan (Korea, Republic of)

1999-03-01

To evaluate CISS MR imaging findings of epidermoid tumor in comparison with conventional spin-echo images. We studied 6 cases of epidermoid tumor in the subarachnoid space. We used a 1.5T MR unit to obtain CISS images(TR/TE/FA ; 12.3msec/5.9 msec/700) and T1- and T2- weighted spin-echo images. CISS MR imaging findings were evaluated with respect to tumor's signal intensity , contour, and relation with adjacent structures. Conspicuity of the tumor was compared between CISS and spin-echo images. A quantitative analysis was performed by measuring tumor to CSF contrast. In qualitative analysis, three radiologists independently compared CISS image and conventional spin-echo images for visibility of the tumor and graded them into three categories( poor, good, and excellent). Epidermoid tumors were located in the cerebellopontine angle in 4 cases, the prepontine cisstern in 1 case, and the cerebellopontine angle-prepontine cistern in 1 case. The tumors were hyperintense relative to brain parenchyma and hypointense relative to CSF on CISS images, were lobulated, encased adjacent cranial nerve and vessels, and invaginated into brain parenchyma. In qualitative analysis, CISS images showed clear demarcation between tumor and CSF, exact tumor extension, and tumor's relation with cranial nerves and vessels better than conventional spin-echo images. In quantitative analysis, the mean contrast values of tumor to CSF on T1-, T2-weighted images, and CISS images were 0.12, 0.06, and 0.52, respectively. The contrast value for CISS images was significantly higher than that for T1-and T2-weighted images(p<0.05). Epidermoid tumors in the subarachnoid space are better demonstrated on CISS images than on conventional spin-echo images. This special MR sequence can be added as a routine protocol in the diagnosis of subarachnoid epidermoid tumor.

Small angle spectrometers: Summary

International Nuclear Information System (INIS)

Courant, E.; Foley, K.J.; Schlein, P.E.

1986-01-01

Aspects of experiments at small angles at the Superconducting Super Collider are considered. Topics summarized include a small angle spectrometer, a high contingency spectrometer, dipole and toroid spectrometers, and magnet choices

Demonstration of angle widening using EyeCam after laser peripheral iridotomy in eyes with angle closure.

Science.gov (United States)

Perera, Shamira A; Quek, Desmond T; Baskaran, Mani; Tun, Tin A; Kumar, Rajesh S; Friedman, David S; Aung, Tin

2010-06-01

To evaluate EyeCam in detecting changes in angle configuration after laser peripheral iridotomy (LPI) in comparison to gonioscopy, the reference standard. Prospective comparative study. Twenty-four subjects (24 eyes) with primary angle-closure glaucoma (PACG) were recruited. Gonioscopy and EyeCam (Clarity Medical Systems) imaging of all 4 angle quadrants were performed, before and 2 weeks after LPI. Images were graded according to angle structures visible by an observer masked to clinical data or the status of LPI, and were performed in a random order. Angle closure in a quadrant was defined as the inability to visualize the posterior trabecular meshwork. We determined the number of quadrants with closed angles and the mean number of clock hours of angle closure before and after LPI in comparison to gonioscopy. Using EyeCam, all 24 eyes showed at least 1 quadrant of angle widening after LPI. The mean number of clock hours of angle closure decreased significantly, from 8.15 +/- 3.47 clock hours before LPI to 1.75 +/- 2.27 clock hours after LPI (P gonioscopy showed 1.0 +/- 1.41 (95% CI, 0.43-1.57) quadrants opening from closed to open after LPI compared to 2.0 +/- 1.28 (95% CI, 1.49-2.51, P = .009) quadrants with EyeCam. Intra-observer reproducibility of grading the extent of angle closure in clock hours in EyeCam images was moderate to good (intraclass correlation coefficient 0.831). EyeCam may be used to document changes in angle configuration after LPI in eyes with PACG. Copyright 2010 Elsevier Inc. All rights reserved.

Behavior of Tilted Angle Shear Connectors

Science.gov (United States)

Khorramian, Koosha; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N. H.

2015-01-01

According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type. PMID:26642193

Behavior of Tilted Angle Shear Connectors.

Directory of Open Access Journals (Sweden)

Koosha Khorramian

Full Text Available According to recent researches, angle shear connectors are appropriate to transfer longitudinal shear forces across the steel-concrete interface. Angle steel profile has been used in different positions as L-shaped or C-shaped shear connectors. The application of angle shear connectors in tilted positions is of interest in this study. This study investigates the behaviour of tilted-shaped angle shear connectors under monotonic loading using experimental push out tests. Eight push-out specimens are tested to investigate the effects of different angle parameters on the ultimate load capacity of connectors. Two different tilted angles of 112.5 and 135 degrees between the angle leg and steel beam are considered. In addition, angle sizes and lengths are varied. Two different failure modes were observed consisting of concrete crushing-splitting and connector fracture. By increasing the size of connector, the maximum load increased for most cases. In general, the 135 degrees tilted angle shear connectors have a higher strength and stiffness than the 112.5 degrees type.

[Pneumocephalus as a cause of a decrease in the bispectral index].

Science.gov (United States)

Herreras Gutiérrez, J L; Gilsanz Rodríguez, F

2014-01-01

A sharp decrease in the values of the bispectral index (BIS), along with an increase in suppression rate, was observed in a patient after the removal of an epidermoid tumor in the cerebellopontine angle by right retrosigmoid access under general anesthesia. This was probably related to a frontal pneumocephalus. No accompanying neurological signs were observed. The patient was extubated in the Recovery Room with no further incidents, as the BIS increased again. The neurosurgeons chose conservative treatment, relying on the reabsorption and redistribution of the air. Copyright © 2012 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Exophytic pilocytic astrocytoma of the brain stem in an adult with encasement of the caudal cranial nerve complex (IX-XII): presurgical anatomical neuroimaging using MRI

Energy Technology Data Exchange (ETDEWEB)

Yousry, Indra; Yousry, Tarek A. [Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilians University, Marchioninistr. 15, 81377, Munich (Germany); Muacevic, Alexander; Olteanu-Nerbe, Vlad [Department of Neurosurgery, Klinikum Grosshadern, Ludwig-Maximilians University, Munich (Germany); Naidich, Thomas P. [Department of Radiology, Section of Neuroradiology, Mount Sinai Hospital, New York (United States)

2004-07-01

We describe a rare case of adult pilocytic astrocytoma in which exophytic growth from the brain stem presented as a right cerebellopontine angle mass. An initial MRI examination using T2- and T1-weighted images without and with contrast suggested the diagnosis of schwannoma. Subsequent use of 3D CISS (three-dimensional constructive interference in steady state) and T1-weighted contrast-enhanced 3D MP-RAGE (three-dimensional magnetization prepared rapid acquisition gradient echo) sequences led to the diagnosis of an exophytic brain stem tumor, documented the precise relationships of the tumor to cranial nerve VIII, revealed encasement of cranial nerves IX-XII (later confirmed intraoperatively), and provided the proper basis for planning surgical management. (orig.)

Trigeminal neuralgia: report of 3 cases

International Nuclear Information System (INIS)

Park, Geum Mee; Ki, Joo Yeon; Cho, Bong Hae; Nah, Kyung Soo

2002-01-01

Orofacial pain can be caused by intracranial disorders or can be musculoskeletal, vascular, internal derangemental, and neurologic in origin. The neurologic pain is derived from structural and functional disorders of nerve, and the trigeminal neuralgia is the typical manifestation. Trigeminal neuralgia is known from centuries ago, and is one of the most common pains in human. We present our experience with three patients who have trigeminal neuralgia. The first case is a 50-year-old female who had no specific evidence radiographically. Second is a 50-year-old male with microvascular compression on right trigeminal nerve. The third case is a 60-year-old female who had a neoplasm in cerebellopontine angle with associated mass effect.

Trigeminal neuralgia: report of 3 cases

Energy Technology Data Exchange (ETDEWEB)

Park, Geum Mee; Ki, Joo Yeon; Cho, Bong Hae; Nah, Kyung Soo [College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

2002-03-15

Orofacial pain can be caused by intracranial disorders or can be musculoskeletal, vascular, internal derangemental, and neurologic in origin. The neurologic pain is derived from structural and functional disorders of nerve, and the trigeminal neuralgia is the typical manifestation. Trigeminal neuralgia is known from centuries ago, and is one of the most common pains in human. We present our experience with three patients who have trigeminal neuralgia. The first case is a 50-year-old female who had no specific evidence radiographically. Second is a 50-year-old male with microvascular compression on right trigeminal nerve. The third case is a 60-year-old female who had a neoplasm in cerebellopontine angle with associated mass effect.

Exophytic pilocytic astrocytoma of the brain stem in an adult with encasement of the caudal cranial nerve complex (IX-XII): presurgical anatomical neuroimaging using MRI

International Nuclear Information System (INIS)

Yousry, Indra; Yousry, Tarek A.; Muacevic, Alexander; Olteanu-Nerbe, Vlad; Naidich, Thomas P.

2004-01-01

We describe a rare case of adult pilocytic astrocytoma in which exophytic growth from the brain stem presented as a right cerebellopontine angle mass. An initial MRI examination using T2- and T1-weighted images without and with contrast suggested the diagnosis of schwannoma. Subsequent use of 3D CISS (three-dimensional constructive interference in steady state) and T1-weighted contrast-enhanced 3D MP-RAGE (three-dimensional magnetization prepared rapid acquisition gradient echo) sequences led to the diagnosis of an exophytic brain stem tumor, documented the precise relationships of the tumor to cranial nerve VIII, revealed encasement of cranial nerves IX-XII (later confirmed intraoperatively), and provided the proper basis for planning surgical management. (orig.)

Computed tomographic findings of cerebral arterial ectasia

International Nuclear Information System (INIS)

Choi, Woo Suk; Ko, Young Ho; Lim, Jae Hoon

1987-01-01

The computed tomographic findings of cerebral arterial ectasia in 8 patients, of which 5 cases were angiographically documented, are reported. The ecstatic arteries, located predominantly in the suprasellar and interpeduncular cisterns, appeared as serpignous, tubular structures on the unenhanced scan. The enhanced CT scan demonstrated dense, sharply defined, homogeneous intraluminal enhancement. Until recently, the diagnosis of cerebral arterial ectasia was usually established by angiography. With introduction of CT it has become possible to noninvasively identify and characterize this vascular disorder and its associated intracranial complications. The vertebrobasilar dolichoectasia may be diagnosed by CT as an extra-axial lesion in the cerebellopontine angle. It enhances in a tubular fashion after intravenous injection of contrast.

Facial neuroma masquerading as acoustic neuroma.

Science.gov (United States)

Sayegh, Eli T; Kaur, Gurvinder; Ivan, Michael E; Bloch, Orin; Cheung, Steven W; Parsa, Andrew T

2014-10-01

Facial nerve neuromas are rare benign tumors that may be initially misdiagnosed as acoustic neuromas when situated near the auditory apparatus. We describe a patient with a large cystic tumor with associated trigeminal, facial, audiovestibular, and brainstem dysfunction, which was suspicious for acoustic neuroma on preoperative neuroimaging. Intraoperative investigation revealed a facial nerve neuroma located in the cerebellopontine angle and internal acoustic canal. Gross total resection of the tumor via retrosigmoid craniotomy was curative. Transection of the facial nerve necessitated facial reanimation 4 months later via hypoglossal-facial cross-anastomosis. Clinicians should recognize the natural history, diagnostic approach, and management of this unusual and mimetic lesion. Copyright © 2014 Elsevier Ltd. All rights reserved.

The impact of inlet angle and outlet angle of guide vane on pump in reversal based hydraulic turbine performance

International Nuclear Information System (INIS)

Shi, F X; Yang, J H; Wang, X H; Zhang, R H; Li, C E

2012-01-01

In this paper, in order to research the impact of inlet angle and outlet angle of guide vane on hydraulic turbine performance, a centrifugal pump in reversal is adopted as turbine. A numerical simulation method is adopted for researching outer performance and flow field of turbine. The results show: inlet angle has a crucial role to turbine, to the same flow, there is a noticeable decline for the efficiency and head of turbine with the inlet angle increases. At the best efficiency point(EFP),to a same inlet angle, when the inlet angle greater than inlet angle, velocity circulation in guide vane outlet decreases, which lead the efficiency of turbine to reduce, Contrarily, the efficiency rises. With the increase of inlet angle and outlet angle, the EFP moves to the big flow area and the uniformity of pressure distribution becomes worse. The paper indicates that the inlet angle and outlet angle have great impact on the turbine performance, and the best combination exists for the inlet angle and outlet angle of the guide vane.

Genetic and Functional Heterogeneity of Tumors in Neurofibromatosis 2

Science.gov (United States)

2016-07-01

see Table 2). Table 2 – Isogenic human arachnoidal cell (AC) clones with NF2 (exon 8) inactivating mutations generated by CRISPR / Cas genome editing...Generation and analysis of RNAseq data from isogenic arachnoidal cells with or without inactivation of NF2, generated using CRISPR / Cas genome editing...potential target for therapeutic intervention. Use of CRISPR / Cas -edited arachnoidal cells to compare complete merlin inactivation with the

Exfoliation of GaAs caused by MeV 1H and 4He ion implantation at left angle 100 right angle , left angle 110 right angle axial and random orientations

International Nuclear Information System (INIS)

Rauhala, E.; Raeisaenen, J.

1994-01-01

The exfoliation procedure of the ion range determination of gaseous implants in single crystal GaAs is investigated. The correlation of the observed crater depth with the ion range is studied for random, left angle 100 right angle and left angle 110 right angle axial orientation high dose implantations of 1.5-2.5 MeV 1 H and 4 He ions. Depending on the experimental conditions, the crater depths corresponded to range values between the modal range and the range maximum. The observed crater depths could be related to the actual He concentration depth distributions by determining the profiles of the 4 He implants by 2.7 MeV proton backscattering. The implantation parameters affecting the exfoliation process, and especially the increase rate of the sample temperature, are investigated. The range distribution parameters for the 1.5 MeV 4 He implants are presented. ((orig.))

Wafer scale oblique angle plasma etching

Science.gov (United States)

Burckel, David Bruce; Jarecki, Jr., Robert L.; Finnegan, Patrick Sean

2017-05-23

Wafer scale oblique angle etching of a semiconductor substrate is performed in a conventional plasma etch chamber by using a fixture that supports a multiple number of separate Faraday cages. Each cage is formed to include an angled grid surface and is positioned such that it will be positioned over a separate one of the die locations on the wafer surface when the fixture is placed over the wafer. The presence of the Faraday cages influences the local electric field surrounding each wafer die, re-shaping the local field to be disposed in alignment with the angled grid surface. The re-shaped plasma causes the reactive ions to follow a linear trajectory through the plasma sheath and angled grid surface, ultimately impinging the wafer surface at an angle. The selected geometry of the Faraday cage angled grid surface thus determines the angle at with the reactive ions will impinge the wafer.

Angles in hyperbolic lattices

DEFF Research Database (Denmark)

Risager, Morten S.; Södergren, Carl Anders

2017-01-01

It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior of the den......It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior...... of the density function in both the small and large variable limits. This extends earlier results by Boca, Pasol, Popa and Zaharescu and Kelmer and Kontorovich in dimension 2 to general dimension n . Our proofs use the decay of matrix coefficients together with a number of careful estimates, and lead...

Optimum Tilt Angle at Tropical Region

Directory of Open Access Journals (Sweden)

S Soulayman

2015-02-01

Full Text Available : One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector Equator facing position is the best, is valid for tropical region? Thus, it is required to determine the optimum tilt as for Equator facing and for Pole oriented collectors. In addition, the question that may arise: how many times is reasonable for adjusting collector tilt angle for a definite value of surface azimuth angle? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle for the solar collector at any latitude. This model was applied for determining optimum tilt angle and orientation in the tropical zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 11% to 18% more than the case of a solar collector fixed on a horizontal surface.

Laser peripheral iridoplasty for angle-closure.

Science.gov (United States)

Ng, Wai Siene; Ang, Ghee Soon; Azuara-Blanco, Augusto

2012-02-15

Angle-closure glaucoma is a leading cause of irreversible blindness in the world. Treatment is aimed at opening the anterior chamber angle and lowering the IOP with medical and/or surgical treatment (e.g. trabeculectomy, lens extraction). Laser iridotomy works by eliminating pupillary block and widens the anterior chamber angle in the majority of patients. When laser iridotomy fails to open the anterior chamber angle, laser iridoplasty may be recommended as one of the options in current standard treatment for angle-closure. Laser peripheral iridoplasty works by shrinking and pulling the peripheral iris tissue away from the trabecular meshwork. Laser peripheral iridoplasty can be used for crisis of acute angle-closure and also in non-acute situations.   To assess the effectiveness of laser peripheral iridoplasty in the treatment of narrow angles (i.e. primary angle-closure suspect), primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) in non-acute situations when compared with any other intervention. In this review, angle-closure will refer to patients with narrow angles (PACs), PAC and PACG. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 12), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 5 January 2012. We included only randomised controlled trials (RCTs) in this review. Patients with narrow angles, PAC or PACG were eligible. We excluded studies that included only patients with acute presentations

Angle parameter changes of phacoemulsification and combined phacotrabeculectomy for acute primary angle closure

Directory of Open Access Journals (Sweden)

Shi-Wei Li

2015-08-01

Full Text Available AIM: To evaluate the difference in angle parameters and clinical outcome following phacoemulsification and combined phacotrabeculectomy in patients with acute primary angle closure (APAC using ultrasound biomicroscopy (UBM.METHODS: Patients (n=23, 31 eyes were randomized to receive phacoemulsification or combined phacotrabeculectomy (n=24, 31 eyes. Best-corrected visual acuity (BCVA, intraocular pressure (IOP, the main complications following surgery, and indentation gonioscopy and angle parameters measured using UBM were documented preoperatively and postoperatively.RESULTS:The improvement in BCVA in the phacoemulsification group was significantly greater than in the combined group (P<0.05. IOP in the phacoemulsification group was slightly higher than in the combined group following 1wk of follow-up (P<0.05, whereas there was no significant difference between the two groups at the latter follow-up (P>0.05. Phacoemulsification alone resulted in a slight increase in the trabecular ciliary processes distance compared with the combined surgery (P<0.05, whereas the other angle parameters showed no significant difference between the groups. Complications in combined group were greater than phacoemulsification only group.CONCLUSION:Both surgeries effectively opened the drainage angle and deepened the anterior chamber, and IOP was well controlled postoperatively. However, phacoemulsification showed better efficacy in improving visual function and showed reduced complications following surgery.

Uncertainty in T1 mapping using the variable flip angle method with two flip angles

International Nuclear Information System (INIS)

Schabel, Matthias C; Morrell, Glen R

2009-01-01

Propagation of errors, in conjunction with the theoretical signal equation for spoiled gradient echo pulse sequences, is used to derive a theoretical expression for uncertainty in quantitative variable flip angle T 1 mapping using two flip angles. This expression is then minimized to derive a rigorous expression for optimal flip angles that elucidates a commonly used empirical result. The theoretical expressions for uncertainty and optimal flip angles are combined to derive a lower bound on the achievable uncertainty for a given set of pulse sequence parameters and signal-to-noise ratio (SNR). These results provide a means of quantitatively determining the effect of changing acquisition parameters on T 1 uncertainty. (note)

Implant Angle Monitor System of MC3-II

International Nuclear Information System (INIS)

Sato, Fumiaki; Sano, Makoto; Nakaoka, Hiroaki; Fujii, Yoshito; Kudo, Tetuya; Nakanishi, Makoto; Koike, Masazumi; Fujino, Yasushi

2008-01-01

Precise implant angle control is required for the latest generation of ion implanters to meet further shrink semiconductor device requirements. Especially, the highest angle accuracy is required for Halo implant process of Logic devices. The Halo implant angle affects the device performance, because slight differences of beam divergence change the overlap profile towards the extension. Additionally, twist angle accuracy is demanded in case of channeling angle implant. Therefore monitoring beam angles and wafer twist angles is important. A new monitoring system for the MC3-II, SEN Corp.'s single wafer type medium current implanter has been developed. This paper describes the angle control performance and monitoring system of the MC3-II. For the twist angle control, we developed a wafer notch angle monitor. The system monitors the wafer notch image on the platen. And the notch angle variation is calculated by using image processing method. It is also able to adjust the notch angle according to the angle error. For the tilt angle control, we developed a vertical beam profile monitor. The monitor system can detect beam profile of vertical directions with horizontally scanning beam. It also measures beam angles of a tilt direction to a wafer. The system configuration and sample beam data are presented.

Experimental study of crossing angle collision

International Nuclear Information System (INIS)

Chen, T.; Rice, D.; Rubin, D.; Sagan, D.; Tigner, M.

1993-01-01

The non-linear coupling due to the beam-beam interaction with crossing angle has been studied. The major effect of a small (∼12mrad) crossing angle is to excite 5Q x ±Q s =integer coupling resonance family on large amplitude particles, which results in bad lifetime. On the CESR, a small crossing angle (∼2.4mr) was created at the IP and a reasonable beam-beam tune-shift was achieved. The decay rate of the beam is measured as a function of horizontal tune with and without crossing angle. The theoretical analysis, simulation and experimental measurements have a good agreement. The resonance strength as a function of crossing angle is also measured

Multi-angle compound imaging

DEFF Research Database (Denmark)

Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Sillesen, Henrik

1998-01-01

This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared to conve......This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared...... to conventional B-mode imaging MACI offers better defined tissue boundaries and lower variance of the speckle pattern, resulting in an image with reduced random variations. Design and implementation of a compound imaging system is described, images of rubber tubes and porcine aorta are shown and effects...... on visualization are discussed. The speckle reduction is analyzed numerically and the results are found to be in excellent agreement with existing theory. An investigation of detectability of low-contrast lesions shows significant improvements compared to conventional imaging. Finally, possibilities for improving...

Early trigeminal nerve involvement in Listeria monocytogenes rhombencephalitis

DEFF Research Database (Denmark)

Karlsson, William K; Harboe, Zitta Barrella; Roed, Casper

2017-01-01

dysfunction on that side. In addition, we identified another 120 cases of Listeria rhombencephalitis following a systematic review. Cranial nerves VII, V, IX, and X, respectively, medulla oblongata, cerebellum and pons, were the most frequently involved brain structures. The present clinical and radiological...... findings corroborate earlier data from animal experiments, indicating that L. monocytogenes may be capable of retrograde intra-axonal migration along the cranial nerves. We suggest that in a subset of patients with rhombencephalitis L. monocytogenes enters the cerebellopontine angle through the trigeminal......Listeria monocytogenes is associated with rhombencephalitis. However, the exact mechanisms of brainstem invasion remains poorly understood. Here, we demonstrate clinical and radiological data suggesting that Listeria may invade the brainstem via the trigeminal nerve. Three females (41, 64 and 70...

Trigemino-cardiac reflex: occurrence of asystole during trans-sphenoidal adenomectomy: a case report.

Science.gov (United States)

Jeon, Dae Geun; Kang, Bong Jin; Hur, Tae Won

2014-09-01

The trigemino-cardiac reflex has been reported to occur during various craniofacial surgeries or procedures including manipulation of the trigeminal ganglion, tumor resection in the cerebellopontine angle, various facial reconstructions and trans-sphenoidal adenomectomy. Regarding risk factors during trans-sphenoidal adenomectomy, invasiveness closely related to the size of tumor and the degree of manipulation of cavernous sinus wall have been reported. We report the case of a 40-year-old female patient who had a relatively small-sized (trans-sphenoidal operation of the wall of the cavernous sinus, which strongly suggests the importance of careful manipulation of the cavernous sinus wall. In addition to reporting this rare complication of trans-sphenoidal adenomectomy, we reviewed its clinical management by performing a literature search.

A lattice determination of gA and left angle x right angle from overlap fermions

International Nuclear Information System (INIS)

Guertler, M.; Schiller, A.; Streuer, T.; Freie Univ. Berlin

2004-10-01

We present results for the nucleon's axial charge g A and the first moment left angle x right angle of the unpolarized parton distribution function from a simulation of quenched overlap fermions. (orig.)

Does the Angle of the Nail Matter for Pertrochanteric Fracture Reduction? Matching Nail Angle and Native Neck-Shaft Angle.

Science.gov (United States)

Parry, Joshua A; Barrett, Ian; Schoch, Bradley; Yuan, Brandon; Cass, Joseph; Cross, William

2018-04-01

To determine whether fixation of pertrochanteric hip fractures with cephalomedullary nails (CMNs) with a neck-shaft angle (NSA) less than the native NSA affects reduction and lag screw cutout. Retrospective comparative study. Level I trauma center. Patients treated with a CMN for unstable pertrochanteric femur fractures (OTA/AO 31-A2.2 and 31-A2.3) between 2005 and 2014. CMN fixation. NSA reduction and lag screw cutout. Patients fixed with a nail angle less than their native NSA were less likely to have good reductions [17% vs. 60%, 95% confidence interval (CI), -63% to -18%; P = 0.0005], secondary to more varus reductions (41% vs. 10%, 95% CI, 9%-46%; P = 0.01) and more fractures with ≥4 mm of displacement (63% vs. 35%, 95% CI, 3%-49%; P = 0.03). The cutout was not associated with the use of a nail angle less than the native NSA (60% vs. 76%, 95% CI, -56% to 18%; P = 0.5), varus reductions (60% vs. 32%, 95% CI, -13% to 62%; P = 0.3), or poor reductions (20% vs. 17%, 95% CI, -24% to 44%; P = 1.0). The fixation of unstable pertrochanteric hip fractures with a nail angle less than the native NSA was associated with more varus reductions and fracture displacement but did not affect the lag screw cutout. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ten helical twist angles of B-DNA

Energy Technology Data Exchange (ETDEWEB)

Kabsch, W; Sander, C; Trifonov, E N

1982-01-01

On the assumption that the twist angles between adjacent base-pairs in the DNA molecule are additive a linear system of 40 equations was derived from experimental measurements of the total twist angles for different pieces of DNA of known sequences. This system of equations is found to be statistically consistent providing a solution for all ten possible twist angles of B-DNA by a least squares fitting procedure. Four of the calculated twist angles were not known before. The other six twist angles calculated are very close to the experimentally measured ones. The data used were obtained by the electrophoretic band-shift method, crystallography and nuclease digestion of DNA adsorbed to mica or Ca-phosphate surface. The validity of the principle of additivity of the twist angles implies that the angle between any particular two base-pairs is a function of only these base-pairs, independent of nearest neighbors.

Anterior Segment Imaging Predicts Incident Gonioscopic Angle Closure.

Science.gov (United States)

Baskaran, Mani; Iyer, Jayant V; Narayanaswamy, Arun K; He, Yingke; Sakata, Lisandro M; Wu, Renyi; Liu, Dianna; Nongpiur, Monisha E; Friedman, David S; Aung, Tin

2015-12-01

To investigate the incidence of gonioscopic angle closure after 4 years in subjects with gonioscopically open angles but varying degrees of angle closure detected on anterior segment optical coherence tomography (AS OCT; Visante; Carl Zeiss Meditec, Dublin, CA) at baseline. Prospective, observational study. Three hundred forty-two subjects, mostly Chinese, 50 years of age or older, were recruited, of whom 65 were controls with open angles on gonioscopy and AS OCT at baseline, and 277 were cases with baseline open angles on gonioscopy but closed angles (1-4 quadrants) on AS OCT scans. All subjects underwent gonioscopy and AS OCT at baseline (horizontal and vertical single scans) and after 4 years. The examiner performing gonioscopy was masked to the baseline and AS OCT data. Angle closure in a quadrant was defined as nonvisibility of the posterior trabecular meshwork by gonioscopy and visible iridotrabecular contact beyond the scleral spur in AS OCT scans. Gonioscopic angle closure in 2 or 3 quadrants after 4 years. There were no statistically significant differences in age, ethnicity, or gender between cases and controls. None of the control subjects demonstrated gonioscopic angle closure after 4 years. Forty-eight of the 277 subjects (17.3%; 95% confidence interval [CI], 12.8-23; P < 0.0001) with at least 1 quadrant of angle closure on AS OCT at baseline demonstrated gonioscopic angle closure in 2 or more quadrants, whereas 28 subjects (10.1%; 95% CI, 6.7-14.6; P < 0.004) demonstrated gonioscopic angle closure in 3 or more quadrants after 4 years. Individuals with more quadrants of angle closure on baseline AS OCT scans had a greater likelihood of gonioscopic angle closure developing after 4 years (P < 0.0001, chi-square test for trend for both definitions of angle closure). Anterior segment OCT imaging at baseline predicts incident gonioscopic angle closure after 4 years among subjects who have gonioscopically open angles and iridotrabecular contact on AS OCT at

Influence of Contact Angle, Growth Angle and Melt Surface Tension on Detached Solidification of InSb

Science.gov (United States)

Wang, Yazhen; Regel, Liya L.; Wilcox, William R.

2000-01-01

We extended the previous analysis of detached solidification of InSb based on the moving meniscus model. We found that for steady detached solidification to occur in a sealed ampoule in zero gravity, it is necessary for the growth angle to exceed a critical value, the contact angle for the melt on the ampoule wall to exceed a critical value, and the melt-gas surface tension to be below a critical value. These critical values would depend on the material properties and the growth parameters. For the conditions examined here, the sum of the growth angle and the contact angle must exceed approximately 130, which is significantly less than required if both ends of the ampoule are open.

The resection angle in apical surgery

DEFF Research Database (Denmark)

von Arx, Thomas; Janner, Simone F M; Jensen, Simon S

2016-01-01

OBJECTIVES: The primary objective of the present radiographic study was to analyse the resection angle in apical surgery and its correlation with treatment outcome, type of treated tooth, surgical depth and level of root-end filling. MATERIALS AND METHODS: In the context of a prospective clinical...... study, cone beam computed tomography (CBCT) scans were taken before and 1 year after apical surgery to measure the angle of the resection plane relative to the longitudinal axis of the root. Further, the surgical depth (distance from the buccal cortex to the most lingual/palatal point of the resection...... or with the retrofilling length. CONCLUSIONS: Statistically significant differences were observed comparing resection angles of different tooth groups. However, the angle had no significant effect on treatment outcome. CLINICAL RELEVANCE: Contrary to common belief, the resection angle in maxillary anterior teeth...

Modified Angle's Classification for Primary Dentition.

Science.gov (United States)

Chandranee, Kaushik Narendra; Chandranee, Narendra Jayantilal; Nagpal, Devendra; Lamba, Gagandeep; Choudhari, Purva; Hotwani, Kavita

2017-01-01

This study aims to propose a modification of Angle's classification for primary dentition and to assess its applicability in children from Central India, Nagpur. Modification in Angle's classification has been proposed for application in primary dentition. Small roman numbers i/ii/iii are used for primary dentition notation to represent Angle's Class I/II/III molar relationships as in permanent dentition, respectively. To assess applicability of modified Angle's classification a cross-sectional preschool 2000 children population from central India; 3-6 years of age residing in Nagpur metropolitan city of Maharashtra state were selected randomly as per the inclusion and exclusion criteria. Majority 93.35% children were found to have bilateral Class i followed by 2.5% bilateral Class ii and 0.2% bilateral half cusp Class iii molar relationships as per the modified Angle's classification for primary dentition. About 3.75% children had various combinations of Class ii relationships and 0.2% children were having Class iii subdivision relationship. Modification of Angle's classification for application in primary dentition has been proposed. A cross-sectional investigation using new classification revealed various 6.25% Class ii and 0.4% Class iii molar relationships cases in preschool children population in a metropolitan city of Nagpur. Application of the modified Angle's classification to other population groups is warranted to validate its routine application in clinical pediatric dentistry.

Nucleation of small angle boundaries

CSIR Research Space (South Africa)

Nabarro, FRN

1996-12-01

Full Text Available The internal stresses induced by the strain gradients in an array of lattice cells delineated by low-angle dislocation boundaries are partially relieved by the creation of new low-angle boundaries. This is shown to be a first-order transition...

Hong's grading for evaluating anterior chamber angle width.

Science.gov (United States)

Kim, Seok Hwan; Kang, Ja Heon; Park, Ki Ho; Hong, Chul

2012-11-01

To compare Hong's grading method with anterior segment optical coherence tomography (AS-OCT), gonioscopy, and the dark-room prone-position test (DRPT) for evaluating anterior chamber width. The anterior chamber angle was graded using Hong's grading method, and Hong's angle width was calculated from the arctangent of Hong's grades. The correlation between Hong's angle width and AS-OCT parameters was analyzed. The area under the receiver operating characteristic curve (AUC) for Hong's grading method when discriminating between narrow and open angles as determined by gonioscopy was calculated. Correlation analysis was performed between Hong's angle width and intraocular pressure (IOP) changes determined by DRPT. A total of 60 subjects were enrolled. Of these subjects, 53.5 % had a narrow angle. Hong's angle width correlated significantly with the AS-OCT parameters (r = 0.562-0.719, P < 0.01). A Bland-Altman plot showed relatively good agreement between Hong's angle width and the angle width obtained by AS-OCT. The ability of Hong's grading method to discriminate between open and narrow angles was good (AUC = 0.868, 95 % CI 0.756-0.942). A significant linear correlation was found between Hong's angle width and IOP change determined by DRPT (r = -0.761, P < 0.01). Hong's grading method is useful for detecting narrow angles. Hong's grading correlated well with AS-OCT parameters and DRPT.

Contact angle hysteresis on superhydrophobic stripes.

Science.gov (United States)

Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I

2014-08-21

We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.

Comparison of axial lengths in occludable angle and angle-closure glaucoma-The Bhaktapur Glaucoma Study

NARCIS (Netherlands)

Thapa, S.S.; Paudyal, I.; Khanal, S.; Paudel, N.; van Rens, G.H.M.B.

2011-01-01

Purpose. To compare the anterior chamber depth (ACD) and axial length of eyes in a population-based sample among normal, occludable angle, and primary angle-closure glaucoma (PACG) groups. Methods. Totally, 3979 subjects from a population-based glaucoma prevalence study underwent complete ocular

Modified angle's classification for primary dentition

Directory of Open Access Journals (Sweden)

Kaushik Narendra Chandranee

2017-01-01

Full Text Available Aim: This study aims to propose a modification of Angle's classification for primary dentition and to assess its applicability in children from Central India, Nagpur. Methods: Modification in Angle's classification has been proposed for application in primary dentition. Small roman numbers i/ii/iii are used for primary dentition notation to represent Angle's Class I/II/III molar relationships as in permanent dentition, respectively. To assess applicability of modified Angle's classification a cross-sectional preschool 2000 children population from central India; 3–6 years of age residing in Nagpur metropolitan city of Maharashtra state were selected randomly as per the inclusion and exclusion criteria. Results: Majority 93.35% children were found to have bilateral Class i followed by 2.5% bilateral Class ii and 0.2% bilateral half cusp Class iii molar relationships as per the modified Angle's classification for primary dentition. About 3.75% children had various combinations of Class ii relationships and 0.2% children were having Class iii subdivision relationship. Conclusions: Modification of Angle's classification for application in primary dentition has been proposed. A cross-sectional investigation using new classification revealed various 6.25% Class ii and 0.4% Class iii molar relationships cases in preschool children population in a metropolitan city of Nagpur. Application of the modified Angle's classification to other population groups is warranted to validate its routine application in clinical pediatric dentistry.

Two Comments on Bond Angles

Science.gov (United States)

Glaister, P.

1997-09-01

Tetrahedral Bond Angle from Elementary Trigonometry The alternative approach of using the scalar (or dot) product of vectors enables the determination of the bond angle in a tetrahedral molecule in a simple way. There is, of course, an even more straightforward derivation suitable for students who are unfamiliar with vectors, or products thereof, but who do know some elementary trigonometry. The starting point is the figure showing triangle OAB. The point O is the center of a cube, and A and B are at opposite corners of a face of that cube in which fits a regular tetrahedron. The required bond angle alpha = AÔB; and using Pythagoras' theorem, AB = 2(square root 2) is the diagonal of a face of the cube. Hence from right-angled triangle OEB, tan(alpha/2) = (square root 2) and therefore alpha = 2tan-1(square root 2) is approx. 109° 28' (see Fig. 1).

Effect of laser peripheral iridotomy on anterior chamber angle anatomy in primary angle closure spectrum eyes

Science.gov (United States)

Kansara, Seema; Blieden, Lauren S.; Chuang, Alice Z.; Baker, Laura A.; Bell, Nicholas P.; Mankiewicz, Kimberly A.; Feldman, Robert M.

2015-01-01

Purpose To evaluate the change in trabecular-iris circumference volume (TICV) after laser peripheral iridotomy (LPI) in primary angle closure (PAC) spectrum eyes Patients and Methods Forty-two chronic PAC spectrum eyes from 24 patients were enrolled. Eyes with anterior chamber abnormalities affecting angle measurement were excluded. Intraocular pressure, slit lamp exam, and gonioscopy were recorded at each visit. Anterior segment optical coherence tomography (ASOCT) with 3D mode angle analysis scans were taken with the CASIA SS-1000 (Tomey Corp., Nagoya, Japan) before and after LPI. Forty-two pre-LPI ASOCT scans and 34 post-LPI ASOCT scans were analyzed using the Anterior Chamber Analysis and Interpretation (ACAI, Houston, TX) software. A mixed-effect model analysis was used to compare the trabecular-iris space area (TISA) changes among 4 quadrants, as well as to identify potential factors affecting TICV. Results There was a significant increase in all average angle parameters after LPI (TISA500, TISA750, TICV500, and TICV750). The magnitude of change in TISA500 in the superior angle was significantly less than the other angles. The changes in TICV500 and TICV750 were not associated with any demographic or ocular characteristics. Conclusion TICV is a useful parameter to quantitatively measure the effectiveness of LPI in the treatment of eyes with PAC spectrum disease. PMID:26066504

Using Digital Technology to See Angles from Different Angles. Part 2: Openings and Turns

Science.gov (United States)

Host, Erin; Baynham, Emily; McMaster, Heather

2015-01-01

Ever wondered how to use technology to teach angles? This article follows on from an earlier article published last year, providing a range of ideas for integrating technology and concrete materials with the teaching of angle concepts. The authors also provide a comprehensive list of free online games and learning objects that can be used to teach…

The analysis of the pathophysiology of syringomyelia by means of magnetic resonance imaging

International Nuclear Information System (INIS)

Abe, Toshiaki

1992-01-01

The pathophysiology of syringomyelia was examined with magnetic resonance imaging (MRI) in 70 patients. According to complications, syringomyelia was classified as being associated with (1) Chiari malformation, (2) both Chiari malformation and basal arachnoiditis, (3) basal arachnoiditis, (4) an obstruction of the foramen Magendie, and (5) spinal arachnoiditis. MRI features in Type 1 included: wedge-shaped herniated tonsils with the cisterna magna, pencil-shaped rostral end of the intraspinal syrinx, and obliterated caudal part of the fourth ventricle. These findings suggested that the herniated tonsils might result in the disturbance of cerebro-spinal fluid (CSF) circulation. In Type 2, the tip of the herniated tonsils was round; a triangular space was noted between the herniated tonsils and the upper spinal cord; the rostral end of the intraspinal syrinx was round; and the caudal part of the fourth ventricle was well visualized. These findings revealed that the brain stem and spinal cord were less pressed, suggesting that CSF circulatory disturbance resulted from basal arachnoiditis around the foramen magnum. In Type 3, the cisterna magna was narrowed by a thickened arachnoid membrane. In type 4, the intraspinal syrinx was directly connected with the fourth ventricle via the patent central canal associated with hydrocephalus. The position of the cerebellar tonsils and the size of the cisterna magna were both normal. In Type 5, a partial adhesion of the arachnoid membrane around the spinal cord was shown, and the syrinx was found extended toward the rostral as well as the caudal direction of the arachnoid adhesion. The rostral end of the syrinx was sometimes changed in size during MRI examinatin. This phenomenon sustained William's theory of 'suck and slosh mechanism' of intraspinal syrinx extension. (N.K.)

Variable angle asymmetric cut monochromator

International Nuclear Information System (INIS)

Smither, R.K.; Fernandez, P.B.

1993-09-01

A variable incident angle, asymmetric cut, double crystal monochromator was tested for use on beamlines at the Advanced Photon Source (APS). For both undulator and wiggler beams the monochromator can expand area of footprint of beam on surface of the crystals to 50 times the area of incident beam; this will reduce the slope errors by a factor of 2500. The asymmetric cut allows one to increase the acceptance angle for incident radiation and obtain a better match to the opening angle of the incident beam. This can increase intensity of the diffracted beam by a factor of 2 to 5 and can make the beam more monochromatic, as well. The monochromator consists of two matched, asymmetric cut (18 degrees), silicon crystals mounted so that they can be rotated about three independent axes. Rotation around the first axis controls the Bragg angle. The second rotation axis is perpendicular to the diffraction planes and controls the increase of the area of the footprint of the beam on the crystal surface. Rotation around the third axis controls the angle between the surface of the crystal and the wider, horizontal axis for the beam and can make the footprint a rectangle with a minimum. length for this area. The asymmetric cut is 18 degrees for the matched pair of crystals, which allows one to expand the footprint area by a factor of 50 for Bragg angles up to 19.15 degrees (6 keV for Si[111] planes). This monochromator, with proper cooling, will be useful for analyzing the high intensity x-ray beams produced by both undulators and wigglers at the APS

Angle measurement with laser feedback instrument.

Science.gov (United States)

Chen, Wenxue; Zhang, Shulian; Long, Xingwu

2013-04-08

An instrument for angle measurement based on laser feedback has been designed. The measurement technique is based on the principle that when a wave plate placed into a feedback cavity rotates, its phase retardation varies. Phase retardation is a function of the rotating angle of the wave plate. Hence, the angle can be converted to phase retardation. The phase retardation is measured at certain characteristic points identified in the laser outputting curve that are then modulated by laser feedback. The angle of a rotating object can be measured if it is connected to the wave plate. The main advantages of this instrument are: high resolution, compact, flexible, low cost, effective power, and fast response.

Gonioscopy in primary angle closure glaucoma.

Science.gov (United States)

Bruno, Christina A; Alward, Wallace L M

2002-06-01

Primary angle closure is a condition characterized by obstruction to aqueous humor outflow by the peripheral iris, and results in changes in the iridocorneal angle that are visible through gonioscopic examination. Gonioscopy in these eyes, however, can be difficult. This chapter discusses techniques that might help in the examination. These include beginning the examination with the inferior angle, methods to help in looking over the iris, cycloplegia, locating the corneal wedge, indentation, van Herick estimation, examining the other eye, and topical glycerin. Finally, there is a discussion about the pathology associated with the closed angle, with emphasis on the appearance of iris bombé, plateau iris, and the distinction between iris processes and peripheral anterior synechiae.

Contact angle distribution of particles at fluid interfaces.

Science.gov (United States)

Snoeyink, Craig; Barman, Sourav; Christopher, Gordon F

2015-01-27

Recent measurements have implied a distribution of interfacially adsorbed particles' contact angles; however, it has been impossible to measure statistically significant numbers for these contact angles noninvasively in situ. Using a new microscopy method that allows nanometer-scale resolution of particle's 3D positions on an interface, we have measured the contact angles for thousands of latex particles at an oil/water interface. Furthermore, these measurements are dynamic, allowing the observation of the particle contact angle with high temporal resolution, resulting in hundreds of thousands of individual contact angle measurements. The contact angle has been found to fit a normal distribution with a standard deviation of 19.3°, which is much larger than previously recorded. Furthermore, the technique used allows the effect of measurement error, constrained interfacial diffusion, and particle property variation on the contact angle distribution to be individually evaluated. Because of the ability to measure the contact angle noninvasively, the results provide previously unobtainable, unique data on the dynamics and distribution of the adsorbed particles' contact angle.

Ring magnet firing angle control

International Nuclear Information System (INIS)

Knott, M.J.; Lewis, L.G.; Rabe, H.H.

1975-01-01

A device is provided for controlling the firing angles of thyratrons (rectifiers) in a ring magnet power supply. A phase lock loop develops a smooth ac signal of frequency equal to and in phase with the frequency of the voltage wave developed by the main generator of the power supply. A counter that counts from zero to a particular number each cycle of the main generator voltage wave is synchronized with the smooth AC signal of the phase lock loop. Gates compare the number in the counter with predetermined desired firing angles for each thyratron and with coincidence the proper thyratron is fired at the predetermined firing angle

Variable-flip-angle spin-echo imaging (VFSE)

International Nuclear Information System (INIS)

Kasai, Toshifumi; Sugimura, Kazuro; Kawamitsu, Hideaki; Yasui, Kiyoshi; Ishida, Tetsuya; Tsukamoto, Tetsuji.

1990-01-01

T 2 weighted imaging provides images with high object contrast for pathologic conditions in which the water content of tissues is increased. The authors predicted theoretical analysis of the effects of changing flip angle, and analyzed the effects in MR imaging of both phantoms and humans. Variable flip angle spin echo MR imaging (VFSE) with a 1,000/80 (repetition time msec/echo time msec) can obtain T 2 weighted image when flip angle is smaller than 80 degrees. VFSE with 40 to 60 degrees flip angle have higher contrast than other flip angle images. Signal to noise ratio (S/N) of VFSE are 55% at a 30 degree, 76% at a 45 degree, 92% at a 60 degree respectively as compared with conventional spin echo image (2000/80, flip angle 90 degree). VFSE is applicable to obtain T 2 weighted image reduced imaging time. (author)

A thermodynamic model of contact angle hysteresis.

Science.gov (United States)

Makkonen, Lasse

2017-08-14

When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.

Solar cell angle of incidence corrections

Science.gov (United States)

Burger, Dale R.; Mueller, Robert L.

1995-01-01

Literature on solar array angle of incidence corrections was found to be sparse and contained no tabular data for support. This lack along with recent data on 27 GaAs/Ge 4 cm by 4 cm cells initiated the analysis presented in this paper. The literature cites seven possible contributors to angle of incidence effects: cosine, optical front surface, edge, shadowing, UV degradation, particulate soiling, and background color. Only the first three are covered in this paper due to lack of sufficient data. The cosine correction is commonly used but is not sufficient when the incident angle is large. Fresnel reflection calculations require knowledge of the index of refraction of the coverglass front surface. The absolute index of refraction for the coverglass front surface was not known nor was it measured due to lack of funds. However, a value for the index of refraction was obtained by examining how the prediction errors varied with different assumed indices and selecting the best fit to the set of measured values. Corrections using front surface Fresnel reflection along with the cosine correction give very good predictive results when compared to measured data, except there is a definite trend away from predicted values at the larger incident angles. This trend could be related to edge effects and is illustrated by a use of a box plot of the errors and by plotting the deviation of the mean against incidence angle. The trend is for larger deviations at larger incidence angles and there may be a fourth order effect involved in the trend. A chi-squared test was used to determine if the measurement errors were normally distributed. At 10 degrees the chi-squared test failed, probably due to the very small numbers involved or a bias from the measurement procedure. All other angles showed a good fit to the normal distribution with increasing goodness-of-fit as the angles increased which reinforces the very small numbers hypothesis. The contributed data only went to 65 degrees

The Influence of Face Angle and Club Path on the Resultant Launch Angle of a Golf Ball

Directory of Open Access Journals (Sweden)

Paul Wood

2018-02-01

Full Text Available A two-part experimental study was conducted in order to better understand how the delivered face angle and club path of a golf club influences the initial launch direction of a golf ball for various club types. A robust understanding of how these parameters influence the ball direction has implications for both coaches and club designers. The first study used a large sample of golfers hitting shots with different clubs. Initial ball direction was measured with a Foresight Sports camera system, while club delivery parameters were recorded with a Vicon motion capture system. The second study used a golf robot and Vision Research camera to measure club and ball parameters. Results from these experiments show that the launch direction fell closer to face angle than club path. The percent toward the face angle ranged from 61% to 83%, where 100% designates a launch angle entirely toward the face angle.

A gallery approach for off-angle iris recognition

Science.gov (United States)

Karakaya, Mahmut; Yoldash, Rashiduddin; Boehnen, Christopher

2015-05-01

It has been proven that hamming distance score between frontal and off-angle iris images of same eye differs in iris recognition system. The distinction of hamming distance score is caused by many factors such as image acquisition angle, occlusion, pupil dilation, and limbus effect. In this paper, we first study the effect of the angle variations between iris plane and the image acquisition systems. We present how hamming distance changes for different off-angle iris images even if they are coming from the same iris. We observe that increment in acquisition angle of compared iris images causes the increment in hamming distance. Second, we propose a new technique in off-angle iris recognition system that includes creating a gallery of different off-angle iris images (such as, 0, 10, 20, 30, 40, and 50 degrees) and comparing each probe image with these gallery images. We will show the accuracy of the gallery approach for off-angle iris recognition.

An Angle Criterion for Riesz Bases

DEFF Research Database (Denmark)

Lindner, Alexander M; Bittner, B.

1999-01-01

We present a characterization of Riesz bases in terms ofthe angles between certain finite dimensional subspaces. Correlationsbetween the bounds of the Riesz basis and the size of the angles arederived....

Goniodysgenesis in familial primary open-angle glaucoma

NARCIS (Netherlands)

Verbraak, F. D.; vd Berg, W.; Delleman, J. W.; Greve, E. L.

1994-01-01

Results of a pilot study to evaluate goniodysgenesis as a cause of familial open-angle glaucoma are reported. Patients with a familial high tension open-angle glaucoma and a goniodysgenetic chamber angle (n = 11), a number of their relatives with glaucoma (n = 12), and their relatives without

Research on recognition of ramp angle based on transducer

Directory of Open Access Journals (Sweden)

Wenhao GU

2015-12-01

Full Text Available Focusing on the recognition of ramp angle, the relationship between the signal of vehicle transducer and real ramp angle is studied. The force change of vehicle on the ramp, and the relationship between the body tilt angle and front and rear suspension scale is discussed. According to the suspension and tire deformation, error angle of the ramp angle is deduced. A mathematical model is established with Matlab/Simulink and used for simulation to generate error curve of ramp angle. The results show that the error angle increases with the increasing of the ramp angle, and the limit value can reach 6.5%, while the identification method can effectively eliminate this error, and enhance the accuracy of ramp angle recognition.

Anterior chamber angle assessment using gonioscopy and ultrasound biomicroscopy.

Science.gov (United States)

Narayanaswamy, Arun; Vijaya, Lingam; Shantha, B; Baskaran, Mani; Sathidevi, A V; Baluswamy, Sukumar

2004-01-01

Comparison of anterior chamber angle measurements using ultrasound biomicroscopy (UBM) and gonioscopy. Five hundred subjects were evaluated for grading of angle width by the Shaffer method. UBM was done in the same group to document angle width, angle opening distance (AOD 500), and anterior chamber depth. Biometric parameters were documented in all subjects. UBM and gonioscopic findings were compared. A study was conducted in 282 men and 218 women with a mean age of 57.32 +/- 12.48 years. Gonioscopic grading was used to segregate occludable (slit-like, grades 1 and 2) from nonoccludable (grades 3 and 4) angles. Subjective assessment by gonioscopy resulted in an overestimation of angle width within the occludable group when compared with values obtained by UBM. This did not affect the segregation of occludable versus nonoccludable angles by gonioscopy. Biometric parameters in eyes with occludable angles were significantly lower in comparison with eyes with nonoccludable angles, except for lens thickness. AOD 500 correlated well with angle width. We concluded that clinical segregation into occludable and nonoccludable angles by an experienced observer using gonioscopy is fairly accurate. However, UBM is required for objective quantification of angles, and AOD 500 can be a reliable and standard parameter to grade angle width.

Frequency scaling for angle gathers

KAUST Repository

Zuberi, M. A H; Alkhalifah, Tariq Ali

2014-01-01

Angle gathers provide an extra dimension to analyze the velocity after migration. Space-shift and time shift-imaging conditions are two methods used to obtain angle gathers, but both are reasonably expensive. By scaling the time-lag axis of the time-shifted images, the computational cost of the time shift imaging condition can be considerably reduced. In imaging and more so Full waveform inversion, frequencydomain Helmholtz solvers are used more often to solve for the wavefields than conventional time domain extrapolators. In such cases, we do not need to extend the image, instead we scale the frequency axis of the frequency domain image to obtain the angle gathers more efficiently. Application on synthetic data demonstrate such features.

Angle imaging: Advances and challenges

Science.gov (United States)

Quek, Desmond T L; Nongpiur, Monisha E; Perera, Shamira A; Aung, Tin

2011-01-01

Primary angle closure glaucoma (PACG) is a major form of glaucoma in large populous countries in East and South Asia. The high visual morbidity from PACG is related to the destructive nature of the asymptomatic form of the disease. Early detection of anatomically narrow angles is important and the subsequent prevention of visual loss from PACG depends on an accurate assessment of the anterior chamber angle (ACA). This review paper discusses the advantages and limitations of newer ACA imaging technologies, namely ultrasound biomicroscopy, Scheimpflug photography, anterior segment optical coherence tomography and EyeCam, highlighting the current clinical evidence comparing these devices with each other and with clinical dynamic indentation gonioscopy, the current reference standard. PMID:21150037

Understanding Angle and Angle Measure: A Design-Based Research Study Using Context Aware Ubiquitous Learning

Science.gov (United States)

Crompton, Helen

2015-01-01

Mobile technologies are quickly becoming tools found in the educational environment. The researchers in this study use a form of mobile learning to support students in learning about angle concepts. Design-based research is used in this study to develop an empirically-substantiated local instruction theory about students' develop of angle and…

Relationship between the Angle of Repose and Angle of Internal ...

African Journals Online (AJOL)

). The angle of internal friction ... compression chambers. Lorenzen, 1957 (quoted by Mohsenin,. 1986), reported that the design of deep ... tiongiven for lateral pressure in deep bins as presented by Mohsenin. (1986). The presence of moisture ...

The qualitative criterion of transient angle stability

DEFF Research Database (Denmark)

Lyu, R.; Xue, Y.; Xue, F.

2015-01-01

In almost all the literatures, the qualitative assessment of transient angle stability extracts the angle information of generators based on the swing curve. As the angle (or angle difference) of concern and the threshold value rely strongly on the engineering experience, the validity and robust...... of these criterions are weak. Based on the stability mechanism from the extended equal area criterion (EEAC) theory and combining with abundant simulations of real system, this paper analyzes the criterions in most literatures and finds that the results could be too conservative or too optimistic. It is concluded...

Medicinal plants in the diet of woolly spider monkeys (Brachyteles arachnoides, E. Geoffroy, 1806 – a bio-rational for the search of new medicines for human use?

Directory of Open Access Journals (Sweden)

Liége M. Petroni

Full Text Available ABSTRACT The present study aimed to compare the plant food diet of woolly spider monkeys (Brachyteles arachnoides inhabiting Intervales State Park in São Paulo, Brazil, with medicinal plant species used by humans in the surrounding areas of the park. The diet of a group of woolly spider monkeys living in an Atlantic forest area was recorded during 43 months of fieldwork. Fifty-three species (87 food items were recorded. Plant specimens were collected and identified at the University of São Paulo and the Botanical Institute of São Paulo State. Using semi-structured interviews, ethnomedicinal data were also collected from four preselected respondents regarding the human therapeutic value of these plants. The study showed that 24.5% (13/53 of these species are used by residents around the park for medicinal purposes. Of these thirteen, seven species also have validated pharmacological properties, and three are utilized by local residents for similar medicinal purposes. Overlap in the plant food/medicinal diet of woolly spider monkey populations elsewhere were also noted, suggesting potential overlap in their medicinal value for humans and primates. The similarities between the ingestion of plants by primates and their medicinal use by humans provide a bio-rational for the search of bioactive plants in the primate diet. Further detailed investigation of their pharmacological and phytochemical value is warranted.

Angle closure glaucoma in congenital ectropion uvea

Directory of Open Access Journals (Sweden)

Grace M. Wang

2018-06-01

Full Text Available Purpose: Congenital ectropion uvea is a rare anomaly, which is associated with open, but dysplastic iridocorneal angles that cause childhood glaucoma. Herein, we present 3 cases of angle-closure glaucoma in children with congenital ectropion uvea. Observations: Three children were initially diagnosed with unilateral glaucoma secondary to congenital ectropion uvea at 7, 8 and 13 years of age. The three cases showed 360° of ectropion uvea and iris stromal atrophy in the affected eye. In one case, we have photographic documentation of progression to complete angle closure, which necessitated placement of a glaucoma drainage device 3 years after combined trabeculotomy and trabeculectomy. The 2 other cases, which presented as complete angle closure, also underwent glaucoma drainage device implantation. All three cases had early glaucoma drainage device encapsulation (within 4 months and required additional surgery (cycloablation or trabeculectomy. Conclusions and importance: Congenital ectropion uvea can be associated with angle-closure glaucoma, and placement of glaucoma drainage devices in all 3 of our cases showed early failure due to plate encapsulation. Glaucoma in congenital ectropion uvea requires attention to angle configuration and often requires multiple surgeries to obtain intraocular pressure control. Keywords: Congenital ectropion uvea, Juvenile glaucoma, Angle-closure glaucoma, Glaucoma drainage device

Spondylolysis and the sacro-horizontal angle in athletes

International Nuclear Information System (INIS)

Swaerd, L.; Hellstroem, M.; Jacobsson, B.; Peterson, L.; Sahlgrenska Sjukhuset, Goeteborg; King Faisal Specialist Hospital and Research Centre, Riyadh

1989-01-01

The frequency of spondylolysis and the relationship between spondylolysis and the sacro-horizontal angle in 143 athletes and 30 non-athletes is reported. Athletes had a larger sacro-horizontal angle than non-athletes. The sacro-horizontal angle was larger in athletes with spondylolysis as compared with those without. An increased incidence of spondylolysis with an increased angle was demonstrated. It is suggested that an increased sacro-horizontal angle may predispose to spondylolysis, especially in combination with the high mechanical loads sustained in certain sports. (orig.)

Spondylolysis and the sacro-horizontal angle in athletes

Energy Technology Data Exchange (ETDEWEB)

Swaerd, L.; Hellstroem, M.; Jacobsson, B.; Peterson, L. (Oestra Sjukhuset, Goeteborg (Sweden). Dept. of Orthopaedics; Sahlgrenska Sjukhuset, Goeteborg (Sweden). Dept. of Diagnostic Radiology; King Faisal Specialist Hospital and Research Centre, Riyadh (Saudi Arabia). Dept. of Radiology)

The frequency of spondylolysis and the relationship between spondylolysis and the sacro-horizontal angle in 143 athletes and 30 non-athletes is reported. Athletes had a larger sacro-horizontal angle than non-athletes. The sacro-horizontal angle was larger in athletes with spondylolysis as compared with those without. An increased incidence of spondylolysis with an increased angle was demonstrated. It is suggested that an increased sacro-horizontal angle may predispose to spondylolysis, especially in combination with the high mechanical loads sustained in certain sports. (orig.).

Adult medulloblastoma: review of 13 cases with emphasis on MRI

International Nuclear Information System (INIS)

Becker, R.L.

1995-01-01

Medulloblastomas are generally associated with childhood, but 14-30% occur in adults, accounting for 1% of adult central nervous system tumors. While approximately one third of adult medulloblastomas present as vermian tumors similar to those seen in childhood, the majority differ substantially from the childhood variety. In this series of 13 patients, 5 had lateral, seemingly extra-axial masses in the cerebellopontine angle or at the tentorium, simulating meningiomas or acoustic neuromas, but angiographic hypovascularity in 2 of the latter suggested a diagnosis other than meningioma. Of 4 paramedian tumors, 3 diffusely infiltrated the cerebellar white matter, showed little or no gadolinium enhancement and were not associated with hydrocephalus. Hydrocephalus was present in less than half of our patients; in childhood the reported incidence is 85-100 %. A possible association with pregnancy was noted. (orig.)

Lipoma of the midbrain: post-mortem finding in a patient with breast cancer

Directory of Open Access Journals (Sweden)

Verônica Maia Gouvea

1989-09-01

Full Text Available Intracranial lipomas are rare, usually do not have clinical expression and are located mare frequently in the corpus callosum. Other locations include the spinal cord, midbrain tectum, superior vermis, tuber cinereum, infundibulum and more rarely cerebellopontine angle, hypothalamus, superior medullary velum and insula. We report the case of a lipoma of the left inferior colliculus which was a post-mortem finding in a woman who died of breast cancer. Although there are reports of intracranial lipomas in patients with malignant tumors there is no explanation for the co-existence of the two tumors. The present tumor also includes a segment of a nerve which is not uncommon, but a less common finding was the presence of nests of Schwann cells within it, shown by immunohistochemistry.

Distinct spontaneous shrinkage of a sporadic vestibular schwannoma

DEFF Research Database (Denmark)

Huang, Xiaowen; Cayé-Thomasen, Per; Stangerup, Sven-Eric

2013-01-01

on "shrinkage" or "negative growth" or "regression" or "involution" of the tumor were selected, and the contents on the rate, extent and mechanism of spontaneous tumor shrinkage were extracted and reviewed. The reported rate of spontaneous shrinkage of vestibular schwannoma is 5-10% of patients managed......We present a case with outspoken spontaneous vestibular schwannoma shrinkage and review the related literature. The patient was initially diagnosed with a left-sided, intrameatal vestibular schwannoma, which subsequently grew into the cerebello-pontine angle (CPA), followed by total shrinkage...... of the CPA component without any intervention over a 12-year observation period. The literature on spontaneous tumor shrinkage was retrieved by searching the subject terms "vestibular schwannoma, conservative management" in PubMed/MEDLINE database, without a time limit. Of the published data, the articles...

Ocular Biometrics of Myopic Eyes With Narrow Angles.

Science.gov (United States)

Chong, Gabriel T; Wen, Joanne C; Su, Daniel Hsien-Wen; Stinnett, Sandra; Asrani, Sanjay

2016-02-01

The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles. Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster. A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15). Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

Mapping of low flip angles in magnetic resonance

International Nuclear Information System (INIS)

Balezeau, Fabien; Saint-Jalmes, Herve; Eliat, Pierre-Antoine; Cayamo, Alejandro Bordelois

2011-01-01

Errors in the flip angle have to be corrected in many magnetic resonance imaging applications, especially for T1 quantification. However, the existing methods of B1 mapping fail to measure lower values of the flip angle despite the fact that these are extensively used in dynamic acquisition and 3D imaging. In this study, the nonlinearity of the radiofrequency (RF) transmit chain, especially for very low flip angles, is investigated and a simple method is proposed to accurately determine both the gain of the RF transmitter and the B1 field map for low flip angles. The method makes use of the spoiled gradient echo sequence with long repetition time (TR), such as applied in the double-angle method. It uses an image acquired with a flip angle of 90 0 as a reference image that is robust to B1 inhomogeneity. The ratio of the image at flip angle alpha to the image at a flip angle of 90 0 enables us to calculate the actual value of alpha. This study was carried out at 1.5 and 4.7 T, showing that the linearity of the RF supply system is highly dependent on the hardware. The method proposed here allows us to measure the flip angle from 1 0 to 60 0 with a maximal uncertainty of 10% and to correct T1 maps based on the variable flip angle method.

Investigations of time resolved x-ray wide-angle scattering and x-ray small-angle scattering at DESY

International Nuclear Information System (INIS)

Zachmann, H.G.; Gehrke, R.; Prieske, W.; Riekel, C.

1985-01-01

Instrumentation is described for the simultaneous wide-angle and small-angle x-ray scattering. The method was applied to the study of the isothermal crystallization of polyethylene terephthalates. In agreement with the classical theories of crystallization, the data showed that the density difference between the crystals and the non-crystalline regions does not change with time. The mechanisms of melting, recrystallization, and crystal thickening were investigated by small-angle x-ray scattering with stepwise changes and continuous changes of temperature using polyethylene terephthalate

Measurement of the angle gamma

International Nuclear Information System (INIS)

Aleksan, R.; Sphicas, P.; Massachusetts Inst. of Tech., Cambridge, MA

1993-12-01

The angle γ as defined in the Wolfenstein approximation is not completely out of reach of current or proposed dedicated B experiments. This work represents but a first step in the direction of extracting the third angle of the unitarity triangle by study the feasibility of using new decay modes in a hadronic machine. (A.B.). 11 refs., 1 fig., 7 tabs

Angle-averaged Compton cross sections

International Nuclear Information System (INIS)

Nickel, G.H.

1983-01-01

The scattering of a photon by an individual free electron is characterized by six quantities: α = initial photon energy in units of m 0 c 2 ; α/sub s/ = scattered photon energy in units of m 0 c 2 ; β = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV

Angle-averaged Compton cross sections

Energy Technology Data Exchange (ETDEWEB)

Nickel, G.H.

1983-01-01

The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.

Angle Kappa and its importance in refractive surgery

Directory of Open Access Journals (Sweden)

Majid Moshirfar

2013-01-01

Full Text Available Angle kappa is the difference between the pupillary and visual axis. This measurement is of paramount consideration in refractive surgery, as proper centration is required for optimal results. Angle kappa may contribute to MFIOL decentration and its resultant photic phenomena. Adjusting placement of MFIOLs for angle kappa is not supported by the literature but is likely to help reduce glare and haloes. Centering LASIK in angle kappa patients over the corneal light reflex is safe, efficacious, and recommended. Centering in-between the corneal reflex and the entrance pupil is also safe and efficacious. The literature regarding PRK in patients with an angle kappa is sparse but centering on the corneal reflex is assumed to be similar to centering LASIK on the corneal reflex. Thus, centration of MFIOLs, LASIK, and PRK should be focused on the corneal reflex for patients with a large angle kappa. More research is needed to guide surgeons′ approach to angle kappa.

Angles of total shifts and angles of maxumum crop during development of faces diagonal to seam strike directions

Directory of Open Access Journals (Sweden)

Н. А. Колесник

2017-06-01

Full Text Available When predicting deformations and determining measures to protect underworked objects, angular parameters are used: the boundary angles, the angles of total shift, the angle of maximum crop. The values of these angular parameters are given in the normative documents, but only for sections across and along the strike of the formation. However, at present, longwall face mining is mainly being carried out along a diagonal direction to the strike of the formation. In connection with this, the determination of the values of the angular parameters for such conditions is a topical task.The method of determination and the analytical dependences of the angles of total shifts and angles of maximum crop in sections of the longitudinal and transverse axes of coal-mining faces developed along diagonal directions to the strike of the formation are proposed. These angular parameters are used for prognosis of deformations of the earth's surface and for determining the characteristic zones of influence of mine workings on the local places.

Preferred nasolabial angle in Middle Eastern population.

Science.gov (United States)

Alharethy, Sami

2017-05-01

To define the preferred nasolabial angle measurement in Middle Eastern population. An observational study was conducted from January 2012 to January 2016 at the Department of Otolaryngology, Head and Neck Surgery, King Abdulaziz University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia. A total of 1027 raters, 506 males, and 521 females were asked to choose the most ideal nasolabial angle for 5 males and 5 females lateral photographs whose nasolabial angle were modified with Photoshop into the following angles (85°, 90°, 95°, 100°, 105°, and 110°). Male raters preferred the angle of 89.5° ± 3.5° (mean ± SD) for males and 90.8° ± 5.6° for females. While female raters preferred the angle of 89.3° ± 3.8° for males and 90.5° ± 4.8° for females. ANOVA test compare means among groups: p: 0.342, and there is no statistically significant difference between groups. The results of our study showed an even more acute angles than degrees found in the literature. It shows that what young generation in our region prefers and clearly reflects that what could be explained as under rotation of the nasal tip in other cultures is just the ideal for some Middle Eastern population.

ASSESSMENT OF LENS THICKNESS IN ANGLE CLOSURE DISEASE

Directory of Open Access Journals (Sweden)

Nishat Sultana Khayoom

2016-08-01

Full Text Available BACKGROUND Anterior chamber depth and lens thickness have been considered as important biometric determinants in primary angle-closure glaucoma. Patients with primary narrow angle may be classified as a primary angle closure suspect (PACS, or as having primary angle closure (PAC or primary angle closure glaucoma (PACG. 23.9% of patients with primary angle closure disease are in India, which highlights the importance of understanding the disease, its natural history, and its underlying pathophysiology, so that we may try to establish effective methods of treatment and preventative measures to delay, or even arrest, disease progression, thereby reducing visual morbidity. AIM To determine the lens thickness using A-scan biometry and its significance in various stages of angle closure disease. MATERIALS AND METHODS Patients attending outpatient department at Minto Ophthalmic Hospital between October 2013 to May 2015 were screened for angle closure disease and subsequently evaluated at glaucoma department. In our study, lens thickness showed a direct correlation with shallowing of the anterior chamber by determining the LT/ ACD ratio. A decrease in anterior chamber depth is proportional to the narrowing of the angle which contributes to the progression of the angle closure disease from just apposition to occlusion enhancing the risk for optic nerve damage and visual field loss. Hence, if the lens thickness values are assessed earlier in the disease process, appropriate intervention can be planned. CONCLUSION Determination of lens changes along with anterior chamber depth and axial length morphometrically can aid in early detection of angle closure. The role of lens extraction for PACG is a subject of increased interest. Lens extraction promotes the benefits of anatomical opening of the angle, IOP reduction and improved vision. This potential intervention may be one among the armamentarium of approaches for PACG. Among the current treatment modalities

Scattering angle-based filtering via extension in velocity

KAUST Repository

Kazei, Vladimir; Tessmer, Ekkehart; Alkhalifah, Tariq

2016-01-01

The scattering angle between the source and receiver wavefields can be utilized in full-waveform inversion (FWI) and in reverse-time migration (RTM) for regularization and quality control or to remove low frequency artifacts. The access to the scattering angle information is costly as the relation between local image features and scattering angles has non-stationary nature. For the purpose of a more efficient scattering angle information extraction, we develop techniques that utilize the simplicity of the scattering angle based filters for constantvelocity background models. We split the background velocity model into several domains with different velocity ranges, generating an

Scattering angle-based filtering via extension in velocity

KAUST Repository

Kazei, Vladimir

2016-09-06

The scattering angle between the source and receiver wavefields can be utilized in full-waveform inversion (FWI) and in reverse-time migration (RTM) for regularization and quality control or to remove low frequency artifacts. The access to the scattering angle information is costly as the relation between local image features and scattering angles has non-stationary nature. For the purpose of a more efficient scattering angle information extraction, we develop techniques that utilize the simplicity of the scattering angle based filters for constantvelocity background models. We split the background velocity model into several domains with different velocity ranges, generating an

Sharper angle, higher risk? The effect of cutting angle on knee mechanics in invasion sport athletes

NARCIS (Netherlands)

Schreurs, Mervin J.; Benjaminse, Anne; Lemmink, Koen A. P. M.

2017-01-01

Introduction: Cutting is an important skill in team-sports, but unfortunately is also related to non-contact ACL injuries. The purpose was to examine knee kinetics and kinematics at different cutting angles. Material and methods: 13 males and 16 females performed cuts at different angles (45°, 90°,

Angle closure glaucoma in congenital ectropion uvea.

Science.gov (United States)

Wang, Grace M; Thuente, Daniel; Bohnsack, Brenda L

2018-06-01

Congenital ectropion uvea is a rare anomaly, which is associated with open, but dysplastic iridocorneal angles that cause childhood glaucoma. Herein, we present 3 cases of angle-closure glaucoma in children with congenital ectropion uvea. Three children were initially diagnosed with unilateral glaucoma secondary to congenital ectropion uvea at 7, 8 and 13 years of age. The three cases showed 360° of ectropion uvea and iris stromal atrophy in the affected eye. In one case, we have photographic documentation of progression to complete angle closure, which necessitated placement of a glaucoma drainage device 3 years after combined trabeculotomy and trabeculectomy. The 2 other cases, which presented as complete angle closure, also underwent glaucoma drainage device implantation. All three cases had early glaucoma drainage device encapsulation (within 4 months) and required additional surgery (cycloablation or trabeculectomy). Congenital ectropion uvea can be associated with angle-closure glaucoma, and placement of glaucoma drainage devices in all 3 of our cases showed early failure due to plate encapsulation. Glaucoma in congenital ectropion uvea requires attention to angle configuration and often requires multiple surgeries to obtain intraocular pressure control.

Neutron spin echo scattering angle measurement (SESAME)

International Nuclear Information System (INIS)

Pynn, R.; Fitzsimmons, M.R.; Fritzsche, H.; Gierlings, M.; Major, J.; Jason, A.

2005-01-01

We describe experiments in which the neutron spin echo technique is used to measure neutron scattering angles. We have implemented the technique, dubbed spin echo scattering angle measurement (SESAME), using thin films of Permalloy electrodeposited on silicon wafers as sources of the magnetic fields within which neutron spins precess. With 30-μm-thick films we resolve neutron scattering angles to about 0.02 deg. with neutrons of 4.66 A wavelength. This allows us to probe correlation lengths up to 200 nm in an application to small angle neutron scattering. We also demonstrate that SESAME can be used to separate specular and diffuse neutron reflection from surfaces at grazing incidence. In both of these cases, SESAME can make measurements at higher neutron intensity than is available with conventional methods because the angular resolution achieved is independent of the divergence of the neutron beam. Finally, we discuss the conditions under which SESAME might be used to probe in-plane structure in thin films and show that the method has advantages for incident neutron angles close to the critical angle because multiple scattering is automatically accounted for

The Effect of Suture Anchor Insertion Angle on Calcaneus Pullout Strength: Challenging the Deadman's Angle.

Science.gov (United States)

Weiss, William M; Saucedo, Ramon P; Robinson, John D; Lo, Chung-Chieh Jason; Morris, Randal P; Panchbhavi, Vinod K

2017-10-01

Refractory cases of Achilles tendinopathy amenable to surgery may include reattachment of the tendon using suture anchors. However, there is paucity of information describing the optimal insertion angle to maximize the tendon footprint and anchor stability in the calcaneus. The purpose of this investigation is to compare the fixation strength of suture anchors inserted at 90° and 45° (the Deadman's angle) relative to the primary compressive trabeculae of the calcaneus. A total of 12 matched pairs of adult cadaveric calcanei were excised and potted to approximate their alignment in vivo. Each pair was implanted with 5.5-mm bioabsorbable suture anchors placed either perpendicular (90°) or oblique (45°) to the primary compressive trabeculae. A tensile load was applied until failure of anchor fixation. Differences in failure load and stiffness between anchor fixation angles were determined by paired t-tests. No significant differences were detected between perpendicular and oblique suture anchor insertion relative to primary compressive trabeculae in terms of load to failure or stiffness. This investigation suggests that the fixation strength of suture anchors inserted perpendicular to the primary compression trabeculae and at the Deadman's angle are possibly comparable. Biomechanical comparison study.

Dynamic angle selection in X-ray computed tomography

Energy Technology Data Exchange (ETDEWEB)

Dabravolski, Andrei, E-mail: andrei.dabravolski@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Batenburg, Kees Joost, E-mail: joost.batenburg@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Centrum Wiskunde and Informatica (CWI), Science Park 123, 1098 XG Amsterdam (Netherlands); Sijbers, Jan, E-mail: jan.sijbers@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium)

2014-04-01

Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes.

Dynamic angle selection in X-ray computed tomography

International Nuclear Information System (INIS)

Dabravolski, Andrei; Batenburg, Kees Joost; Sijbers, Jan

2014-01-01

Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes

Luminosity Anti-leveling with Crossing Angle (MD 1669)

CERN Document Server

Gorzawski, Arkadiusz; Ponce, Laurette; Salvachua Ferrando, Belen Maria; Wenninger, Jorg; CERN. Geneva. ATS Department

2016-01-01

A significant fraction of the LHC luminosity ($\\sim$30\\% in 2016) is lost due to the presence (and necessity) of the crossing angles at the IPs. At the LHC the crossing angle is typically set to a value that provides sufficient separation of the beams at the start of fills for the peak bunch intensities. As the bunch intensity decays during a fill, it is possible to reduce the crossing angle and recover some luminosity. A smooth crossing angle reduction procedure must be developed to take advantage of this option during stable beam operation. During this MD a smooth procedure for luminosity leveling with crossing angle was tested. It was demonstrated that the orbit was well controlled, beam losses were low and the offset leveled experiments ALICE and LHCb were not affected by crossing angle leveling in ATLAS and CMS.

Graphene spin valve: An angle sensor

Energy Technology Data Exchange (ETDEWEB)

Iqbal, Muhammad Zahir, E-mail: zahir.upc@gmail.com [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Hussain, Ghulam [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Siddique, Salma [Department of Bioscience & Biotechnology, Sejong University, Seoul 143-747 (Korea, Republic of); Iqbal, Muhammad Waqas [Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, Lahore (Pakistan)

2017-06-15

Graphene spin valves can be optimized for various spintronic applications by tuning the associated experimental parameters. In this work, we report the angle dependent magnetoresistance (MR) in graphene spin valve for different orientations of applied magnetic field (B). The switching points of spin valve signals show a clear shift towards higher B for each increasing angle of the applied field, thus sensing the response for respective orientation of the magnetic field. The angular variation of B shifts the switching points from ±95 G to ±925 G as the angle is varied from 0° to 90° at 300 K. The observed shifts in switching points become more pronounced (±165 G to ±1450 G) at 4.2 K for similar orientation. A monotonic increase in MR ratio is observed as the angle of magnetic field is varied in the vertical direction at 300 K and 4.2 K temperatures. This variation of B (from 0° to 90°) increases the magnitude of MR ratio from ∼0.08% to ∼0.14% at 300 K, while at 4.2 K it progresses to ∼0.39% from ∼0.14%. The sensitivity related to angular variation of such spin valve structure can be employed for angle sensing applications.

Apparatus and method for variable angle slant hole collimator

Science.gov (United States)

Lee, Seung Joon; Kross, Brian J.; McKisson, John E.

2017-07-18

A variable angle slant hole (VASH) collimator for providing collimation of high energy photons such as gamma rays during radiological imaging of humans. The VASH collimator includes a stack of multiple collimator leaves and a means of quickly aligning each leaf to provide various projection angles. Rather than rotate the detector around the subject, the VASH collimator enables the detector to remain stationary while the projection angle of the collimator is varied for tomographic acquisition. High collimator efficiency is achieved by maintaining the leaves in accurate alignment through the various projection angles. Individual leaves include unique angled cuts to maintain a precise target collimation angle. Matching wedge blocks driven by two actuators with twin-lead screws accurately position each leaf in the stack resulting in the precise target collimation angle. A computer interface with the actuators enables precise control of the projection angle of the collimator.

EFFECT OF SWEEP ANGLE ON THE VORTICAL FLOW OVER DELTA WINGS AT AN ANGLE OF ATTACK OF 10°

Directory of Open Access Journals (Sweden)

JAMES BRETT

2014-12-01

Full Text Available CFD simulations have been used to analyse the vortical flows over sharp edged delta wings with differing sweep angles under subsonic conditions at an angle of attack of 10°. RANS simulations were validated against experimental data for a 65° sweep wing, with a flat cross-section, and the steadiness of the flow field was assessed by comparing the results against unsteady URANS and DES simulations. To assess the effect of sweep angle on the flow field, a range of sweep angles from 65° to 43° were simulated. For moderate sweep wings the primary vortex was observed to detach from the leading edge, undergoing vortex breakdown, and a weaker, replacement, "shadow" vortex was formed. The shadow vortex was observed for sweep angles of 50° and less, and resulted in reduced lift production near the wing tips loss of the stronger primary vortex.

Trabecular Meshwork Height in Primary Open-Angle Glaucoma Versus Primary Angle-Closure Glaucoma.

Science.gov (United States)

Masis, Marisse; Chen, Rebecca; Porco, Travis; Lin, Shan C

2017-11-01

To determine if trabecular meshwork (TM) height differs between primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) eyes. Prospective, cross-sectional clinical study. Adult patients were consecutively recruited from glaucoma clinics at the University of California, San Francisco, from January 2012 to July 2015. Images were obtained from spectral-domain optical coherence tomography (Cirrus OCT; Carl Zeiss Meditec, Inc, Dublin, California, USA). Univariate and multivariate linear mixed models comparing TM height and glaucoma type were performed to assess the relationship between TM height and glaucoma subtype. Mixed-effects regression was used to adjust for the use of both eyes in some subjects. The study included 260 eyes from 161 subjects, composed of 61 men and 100 women. Mean age was 70 years (SD 11.77). There were 199 eyes (123 patients) in the POAG group and 61 eyes (38 patients) in the PACG group. Mean TM heights in the POAG and PACG groups were 812 ± 13 μm and 732 ± 27 μm, respectively, and the difference was significant in univariate analysis (P = .004) and in multivariate analysis (β = -88.7 [24.05-153.5]; P = .008). In this clinic-based population, trabecular meshwork height is shorter in PACG patients compared to POAG patients. This finding may provide insight into the pathophysiology of angle closure and provide assistance in future diagnosis, prevention, and management of the angle-closure spectrum of disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

Dosimetric Comparison of Manual and Beam Angle Optimization of Gantry Angles in IMRT

International Nuclear Information System (INIS)

Srivastava, Shiv P.; Das, Indra J.; Kumar, Arvind; Johnstone, Peter A.S.

2011-01-01

Dosimetric comparison of manual beam angle selection (MBS) and beam angle optimization (BAO) for IMRT plans is investigated retrospectively for 15 head and neck and prostate patients. The head and neck and prostate had planning target volumes (PTVs) ranging between 96.0 and 319.9 cm 3 and 153.6 and 321.3 cm 3 , whereas OAR ranged between 8.3 and 47.8 cm 3 and 68.3 and 469.2 cm 3 , respectively. In MBS, a standard coplanar 7-9 fields equally spaced gantry angles were used. In BAO, the selection of gantry angle was optimized by the algorithm for the same number of beams. The optimization and dose-volume constraints were kept the same for both techniques. Treatment planning was performed on the Eclipse treatment planning system. Our results showed that the dose-volume histogram for PTV are nearly identical in both techniques but BAO provided superior sparing of the organs at risk compared with the MBS. Also, MBS produced statistically significant higher monitor units (MU) and segments than the BAO; 13.1 ± 6.6% (p = 0.012) and 10.4 ± 13.6% (p = 0.140), and 14.6 ± 5.6% (p = 1.003E-5) and 12.6 ± 7.4% (p = 0.76E-3) for head and neck and prostate cases, respectively. The reduction in MU translates into the reduction in total body and integral dose. It is concluded that BAO provides advantage over MBS for most intenisty-modulated radiation therapy cases.

Scoliosis angle. Conceptual basis and proposed definition

Energy Technology Data Exchange (ETDEWEB)

Marklund, T [Linkoepings Hoegskola (Sweden)

1978-01-01

The most commonly used methods of assessing the scoliotic deviation measure angles that are not clearly defined in relation to the anatomy of the patient. In order to give an anatomic basis for such measurements it is proposed to define the scoliotic deviation as the deviation the vertebral column makes with the sagittal plane. Both the Cobb and the Ferguson angles may be based on this definition. The present methods of measurement are then attempts to measure these angles. If the plane of these angles is parallel to the film, the measurement will be correct. Errors in the measurements may be incurred by the projection. A hypothetical projection, called a 'rectified orthogonal projection', is presented, which correctly represents all scoliotic angles in accordance with these principles. It can be constructed in practice with the aid of a computer and by performing measurements on two projections of the vertebral column; a scoliotic curve can be represented independent of the kyphosis and lordosis.

Deep learning methods for protein torsion angle prediction.

Science.gov (United States)

Li, Haiou; Hou, Jie; Adhikari, Badri; Lyu, Qiang; Cheng, Jianlin

2017-09-18

Deep learning is one of the most powerful machine learning methods that has achieved the state-of-the-art performance in many domains. Since deep learning was introduced to the field of bioinformatics in 2012, it has achieved success in a number of areas such as protein residue-residue contact prediction, secondary structure prediction, and fold recognition. In this work, we developed deep learning methods to improve the prediction of torsion (dihedral) angles of proteins. We design four different deep learning architectures to predict protein torsion angles. The architectures including deep neural network (DNN) and deep restricted Boltzmann machine (DRBN), deep recurrent neural network (DRNN) and deep recurrent restricted Boltzmann machine (DReRBM) since the protein torsion angle prediction is a sequence related problem. In addition to existing protein features, two new features (predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments) are used as input to each of the four deep learning architectures to predict phi and psi angles of protein backbone. The mean absolute error (MAE) of phi and psi angles predicted by DRNN, DReRBM, DRBM and DNN is about 20-21° and 29-30° on an independent dataset. The MAE of phi angle is comparable to the existing methods, but the MAE of psi angle is 29°, 2° lower than the existing methods. On the latest CASP12 targets, our methods also achieved the performance better than or comparable to a state-of-the art method. Our experiment demonstrates that deep learning is a valuable method for predicting protein torsion angles. The deep recurrent network architecture performs slightly better than deep feed-forward architecture, and the predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments are useful features for improving prediction accuracy.

Small-angle neutron-scattering experiments

International Nuclear Information System (INIS)

Hardy, A.D.; Thomas, M.W.; Rouse, K.D.

1981-04-01

A brief introduction to the technique of small-angle neutron scattering is given. The layout and operation of the small-angle scattering spectrometer, mounted on the AERE PLUTO reactor, is also described. Results obtained using the spectrometer are presented for three materials (doped uranium dioxide, Magnox cladding and nitrided steel) of interest to Springfields Nuclear Power Development Laboratories. The results obtained are discussed in relation to other known data for these materials. (author)

Thumb rule of visual angle: a new confirmation.

Science.gov (United States)

Groot, C; Ortega, F; Beltran, F S

1994-02-01

The classical thumb rule of visual angle was reexamined. Hence, the visual angle was measured as a function of a thumb's width and the distance between eye and thumb. The measurement of a thumb's width when held at arm's length was taken on 67 second-year students of psychology. The visual angle was about 2 degrees as R. P. O'Shea confirmed in 1991. Also, we confirmed a linear relationship between the size of a thumb's width at arm's length and the visual angle.

Complications and Reoperations in Mandibular Angle Fractures.

Science.gov (United States)

Chen, Collin L; Zenga, Joseph; Patel, Ruchin; Branham, Gregory

2018-05-01

Mandible angle fractures can be repaired in a variety of ways, with no consensus on the outcomes of complications and reoperation rates. To analyze patient, injury, and surgical factors, including approach to the angle and plating technique, associated with postoperative complications, as well as the rate of reoperation with regard to mandible angle fractures. Retrospective cohort study analyzing the surgical outcomes of patients with mandible angle fractures between January 1, 2000, and December 31, 2015, who underwent open reduction and internal fixation. Patients were eligible if they were aged 18 years or older, had 3 or less mandible fractures with 1 involving the mandibular angle, and had adequate follow-up data. Patients with comminuted angle fractures, bilateral angle fractures, and multiple surgical approaches were excluded. A total of 135 patients were included in the study. All procedures were conducted at a single, large academic hospital located in an urban setting. Major complications and reoperation rates. Major complications included in this study were nonunion, malunion, severe malocclusion, severe infection, and exposed hardware. Of 135 patients 113 (83.7%) were men; median age was 29 years (range, 18-82 years). Eighty-seven patients (64.4%) underwent the transcervical approach and 48 patients (35.6%) received the transoral approach. Fifteen (17.2%) patients in the transcervical group and 9 (18.8%) patients in the transoral group experienced major complications (difference, 1%; 95% CI, -8% to 10%). Thirteen (14.9%) patients in the transcervical group and 8 (16.7%) patients in the transoral group underwent reoperations (difference, 2%; 95% CI, -13% to 17%). Active smoking had a significant effect on the rate of major complications (odds ratio, 4.04; 95% CI, 1.07 to 15.34; P = .04). During repair of noncomminuted mandibular angle fractures, both of the commonly used approaches-transcervical and transoral-can be used during treatment with equal

Angle Stability Analysis for Voltage-Controlled Converters

DEFF Research Database (Denmark)

Lin, Hengwei; Jia, Chenxi; Guerrero, Josep M.

2017-01-01

a criterion to analyze the quasi-steady angle stability and the direct current (DC) side stability for VSCs. The operating limit and the angle instability mechanism are revealed, which is generally applicable to the voltage-controlled converters. During the analysis, the influence of the parameters on angle...... stability is studied. Further, the difference on instability mechanism between power electronic converters and synchronous generators are explained in detail. Finally, experiment results with corrective actions verify the analysis....

Page 1 '---------------------------- Presenting features ofprimary angle ...

African Journals Online (AJOL)

coma were assessed. The diagnosis of primary angle-closure glaucoma was made on presentation if the intra-ocular pressure was > 21 mmHg, or if a glaucomatous visual field was found, in the presence of a partially or totally closed angle or peripheral anterior synechiae. Provocation tests were not performed. Patients ...

Beam-beam collisions and crossing angles in RHIC

International Nuclear Information System (INIS)

Peggs, S.

1999-01-01

This paper evaluates the strength of head on and parasitic beam-beam collisions in RHIC when the crossing angle is zero. A non-zero crossing angle is not required in normal operation with 120 bunches, thanks to the early separation of the two beams. The RHIC lattice is shown to easily accommodate even conservatively large crossing angles, for example in beam dynamics studies, or in future operational upgrades to as many as 360 bunches per ring. A modest loss in luminosity is incurred when gold ions collide at an angle after 10 hours of storage

Bounded-Angle Iterative Decoding of LDPC Codes

Science.gov (United States)

Dolinar, Samuel; Andrews, Kenneth; Pollara, Fabrizio; Divsalar, Dariush

2009-01-01

Bounded-angle iterative decoding is a modified version of conventional iterative decoding, conceived as a means of reducing undetected-error rates for short low-density parity-check (LDPC) codes. For a given code, bounded-angle iterative decoding can be implemented by means of a simple modification of the decoder algorithm, without redesigning the code. Bounded-angle iterative decoding is based on a representation of received words and code words as vectors in an n-dimensional Euclidean space (where n is an integer).

Effectiveness of Variable-Gain Kalman Filter Based on Angle Error Calculated from Acceleration Signals in Lower Limb Angle Measurement with Inertial Sensors

Science.gov (United States)

Watanabe, Takashi

2013-01-01

The wearable sensor system developed by our group, which measured lower limb angles using Kalman-filtering-based method, was suggested to be useful in evaluation of gait function for rehabilitation support. However, it was expected to reduce variations of measurement errors. In this paper, a variable-Kalman-gain method based on angle error that was calculated from acceleration signals was proposed to improve measurement accuracy. The proposed method was tested comparing to fixed-gain Kalman filter and a variable-Kalman-gain method that was based on acceleration magnitude used in previous studies. First, in angle measurement in treadmill walking, the proposed method measured lower limb angles with the highest measurement accuracy and improved significantly foot inclination angle measurement, while it improved slightly shank and thigh inclination angles. The variable-gain method based on acceleration magnitude was not effective for our Kalman filter system. Then, in angle measurement of a rigid body model, it was shown that the proposed method had measurement accuracy similar to or higher than results seen in other studies that used markers of camera-based motion measurement system fixing on a rigid plate together with a sensor or on the sensor directly. The proposed method was found to be effective in angle measurement with inertial sensors. PMID:24282442

Cosmic ray zenith angle distribution at low geomagnetic latitude

Energy Technology Data Exchange (ETDEWEB)

Aragon, G [Instituto de Astronomia y Fisica del Espacio, Buenos Aires, Argentina; Gagliardini, A; Ghielmetti, H S

1977-12-01

The intensity of secondary charged cosmic rays at different zenith angles was measured by narrow angle Geiger-Mueller telescopes up to an atmospheric depth of 2 g cm/sup -2/. The angular distribution observed at high altitudes is nearly flat at small angles around the vertical and suggests that the particle intensity peaks at large zenith angles, close to the horizon.

Light Scattering at Various Angles

Science.gov (United States)

Latimer, Paul; Pyle, B. E.

1972-01-01

The Mie theory of scattering is used to provide new information on how changes in particle volume, with no change in dry weight, should influence light scattering for various scattering angles and particle sizes. Many biological cells (e.g., algal cells, erythrocytes) and large subcellular structures (e.g., chloroplasts, mitochondria) in suspension undergo this type of reversible volume change, a change which is related to changes in the rates of cellular processes. A previous study examined the effects of such volume changes on total scattering. In this paper scattering at 10° is found to follow total scattering closely, but scattering at 45°, 90°, 135°, and 170° behaves differently. Small volume changes can cause very large observable changes in large angle scattering if the sample particles are uniform in size; however, the natural particle size heterogeneity of most samples would mask this effect. For heterogeneous samples of most particle size ranges, particle shrink-age is found to increase large angle scattering. PMID:4556610

The Dual-Angle Method for Fast, Sensitive T1 Measurement in Vivo with Low-Angle Adiabatic Pulses

Science.gov (United States)

Bottomley, P. A.; Ouwerkerk, R.

A new method for measuring T1 based on a measurement of the ratio, R, of the steady-state partially saturated NMR signals acquired at two fixed low flip angles (hip-angle and excitation-field ( B1) inhomogeneity result in roughly proportionate errors in the apparent T1. The method is best implemented with adiabatic low-angle pulses such as B1-independent rotation (BIR-4) or BIR-4 phase-cycled (BIRP) pulses, which permit measurements with surface coils. Experimental validation was obtained at 2 T by comparison of unlocalized inversion-recovery and dual-angle proton ( 1H) and phosphorus ( 31P) measurements from vials containing doped water with 0.04 ≤ T1 ≤ 2.8 s and from the metabolites in the calf muscles of eight human volunteers. Calf muscle values of 6 ± 0.5 s for phosphocreatine and around 3.7 ± 0.8 s for the adenosine triphosphates (ATP) were in good agreement with inversion-recovery T1 values and values from the literature. Use of the dual-angle method accelerated T1 measurement time by about fivefold over inversion recovery. The dual-angle method was implemented in a one-dimensional localized surface-coil 31P spectroscopy sequence, producing consistent T1 measurements from phantoms, the calf muscle, and the human liver. 31P T1 values of ATP in the livers of six volunteers were about 0.5 ± 0.1 to 0.6 ± 0.2 s: the total exam times were about 35 minutes per subject. The method is ideally suited to low-sensitivity and/or low-concentration moieties, such as in 31P NMR in vivo, where study-time limitations are critical, and for rapid 1H T1 imaging.

Postoperative pulmonary complication after neurosurgery: A case of unilateral lung collapse.

Science.gov (United States)

Misra, Shilpi

2016-01-01

Pulmonary complications, especially postoperative pulmonary complications, are an important cause of morbidity and mortality in neurosurgical patients. Hypoxemia due to mucus plug causing lung collapse is a rare event. We report a case of a 40-year-old female with right cerebellopontine angle space occupying lesion, scheduled for elective craniotomy and tumor excision. The patient underwent surgery uneventfully and was shifted to Intensive Care Unit (ICU) for monitoring. Eight hours after extubation, she developed hypoxemia due to mucus plug resulting in left lung collapse. She was intubated, and mucus plug was aspirated through sterile endobronchial tube suction which resulted in reexpansion of the collapsed lung. The patient was managed with postural drainage, chest physiotherapy, and antibiotics and extubated after 24 h. This type of pulmonary complication may have a catastrophic course, especially in neurosurgical patients, if not diagnosed and managed in time.

[An improved case of bedridden mental impairment with normal pressure hydrocephalus associated with acoustic neurinoma after tumor resection].

Science.gov (United States)

Sugimoto, Seiichiro; Sugimoto, Akiko; Saita, Kazuko; Kishi, Masahiko; Shioya, Keiichi; Higa, Toshinobu

2008-08-01

A 67-year-old woman developed gait disturbance, dysarthria, cognitive impairment and incontinence at age 65, and became bedridden. She showed mutism, stupor and lower limb spasticity. Cranial CT and MRI revealed marked ventricular enlargement and a cerebellopontine angle tumor. CSF study showed normal pressure (125 mmH2O) and elevated protein (143 mg/dl). Radionuclide cisternography showed redistribution of radionuclide to the ventricles and intraventricular residual radionuclide after 72 hours, which allowed a diagnosis of normal pressure hydrocephalus. After removal of the tumor, ventricle size and CSF protein decreased, and the symptoms of cognitive impairment and motor dysfunction resolved. Histological examination showed acoustic neurinoma. Over the half of hydrocephalus following acoustic neurinoma shows a tendency to improve by surgical resection of the tumor. Neurologists who see cognitively impaired spastic bedridden patients should not overlook this pathology.

Angle independent velocity spectrum determination

DEFF Research Database (Denmark)

2014-01-01

An ultrasound imaging system (100) includes a transducer array (102) that emits an ultrasound beam and produces at least one transverse pulse-echo field that oscillates in a direction transverse to the emitted ultrasound beam and that receive echoes produced in response thereto and a spectral vel...... velocity estimator (110) that determines a velocity spectrum for flowing structure, which flows at an angle of 90 degrees and flows at angles less than 90 degrees with respect to the emitted ultrasound beam, based on the received echoes....

Temperature dependence of Brewster's angle.

Science.gov (United States)

Guo, Wei

2018-01-01

In this work, a dielectric at a finite temperature is modeled as an ensemble of identical atoms moving randomly around where they are trapped. Light reflection from the dielectric is then discussed in terms of atomic radiation. Specific calculation demonstrates that because of the atoms' thermal motion, Brewster's angle is, in principle, temperature-dependent, and the dependence is weak in the low-temperature limit. What is also found is that the Brewster's angle is nothing but a result of destructive superposition of electromagnetic radiation from the atoms.

Non-contact measurement of rotation angle with solo camera

Science.gov (United States)

Gan, Xiaochuan; Sun, Anbin; Ye, Xin; Ma, Liqun

2015-02-01

For the purpose to measure a rotation angle around the axis of an object, a non-contact rotation angle measurement method based on solo camera was promoted. The intrinsic parameters of camera were calibrated using chessboard on principle of plane calibration theory. The translation matrix and rotation matrix between the object coordinate and the camera coordinate were calculated according to the relationship between the corners' position on object and their coordinates on image. Then the rotation angle between the measured object and the camera could be resolved from the rotation matrix. A precise angle dividing table (PADT) was chosen as the reference to verify the angle measurement error of this method. Test results indicated that the rotation angle measurement error of this method did not exceed +/- 0.01 degree.

Contact angle of unset elastomeric impression materials.

Science.gov (United States)

Menees, Timothy S; Radhakrishnan, Rashmi; Ramp, Lance C; Burgess, John O; Lawson, Nathaniel C

2015-10-01

Some elastomeric impression materials are hydrophobic, and it is often necessary to take definitive impressions of teeth coated with some saliva. New hydrophilic materials have been developed. The purpose of this in vitro study was to compare contact angles of water and saliva on 7 unset elastomeric impression materials at 5 time points from the start of mixing. Two traditional polyvinyl siloxane (PVS) (Aquasil, Take 1), 2 modified PVS (Imprint 4, Panasil), a polyether (Impregum), and 2 hybrid (Identium, EXA'lence) materials were compared. Each material was flattened to 2 mm and a 5 μL drop of distilled water or saliva was dropped on the surface at 25 seconds (t0) after the start of mix. Contact angle measurements were made with a digital microscope at initial contact (t0), t1=2 seconds, t2=5 seconds, t3=50% working time, and t4=95% working time. Data were analyzed with a generalized linear mixed model analysis, and individual 1-way ANOVA and Tukey HSD post hoc tests (α=.05). For water, materials grouped into 3 categories at all time-points: the modified PVS and one hybrid material (Identium) produced the lowest contact angles, the polyether material was intermediate, and the traditional PVS materials and the other hybrid (EXA'lence) produced the highest contact angles. For saliva, Identium, Impregum, and Imprint 4 were in the group with the lowest contact angle at most time points. Modified PVS materials and one of the hybrid materials are more hydrophilic than traditional PVS materials when measured with water. Saliva behaves differently than water in contact angle measurement on unset impression material and produces a lower contact angle on polyether based materials. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The ideal male jaw angle--An Internet survey.

Science.gov (United States)

Mommaerts, Maurice Y

2016-04-01

The ideal male jaw angle has not been established. With the advent of additive manufacturing, precise customized shaping is a reality. This study aimed to define the ideal masculine mandibular angle as an aid for 3-dimensional (3D) design. An Internet survey was conducted using black/white photographs of celebrities and non-celebrities. Preferences regarding gonial angle (profile and frontal views), intergonial width and vertical jaw angle position (face frontal view), and angle curvature and definition in oblique views were obtained using simplified, unbalanced Likert scales. Constructs were defined for planning 3D implant designs. The preferred jaw angle had these characteristics: 130° in face profile view, intergonial width similar to facial width, vertical position in frontal view at the oral commissure or at least not below the lower lip, jawline slope in the face frontal view nearly parallel to (with a maximum 15° downward deviation from) a line extending from the lateral canthus to the alare, ascending ramus slope 65°-75° to the Frankfort horizontal, and curvature in the oblique view visible from earlobe to chin and not pointy. Photogrammetric analysis of panel preferences lead to constructs with values useful for the design of 3D printed jaw angles. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

A Viewpoint on the Quantity "Plane Angle"

Science.gov (United States)

Eder, W. E.

1982-01-01

Properties of the quantity "plane angle" are explored under the hypothesis that it is a dimensional quantity. The exploration proceeds especially with respect to the physical concept, its mathematical treatment, vector concepts, measurement theory, units of related quantities, engineering pragmatism, and SI. An attempt is made to bring these different relations into a rational, logical and consistent framework, and thus to justify the hypothesis. Various types of vectorial quantities are recognized, and their properties described with an outline of the necessary algebraic manipulations. The concept of plane angle is amplified, and its interdependence with the circular arc is explored. The resulting units of plane angle form a class of similar scales of measurement. Consequences of the confirmed hypothesis are developed for mathematical expressions involving trigonometric functions, rotational volumes and areas, mathematical limits, differentiation and series expansion. Consequences for mechanical rotational quantities are developed, with proposals for revisions to a number of expressions for derived units within SI. A revised definition for the quantity "plane angle" is stated to take account of the developed insights. There is a clear need to reconsider the status of plane angle and some other quantities within the international framework of SI.

Optical fibre angle sensor used in MEMS

International Nuclear Information System (INIS)

Golebiowski, J; Milcarz, Sz; Rybak, M

2014-01-01

There is a need for displacement and angle measurements in many movable MEMS structures. The use of fibre optical sensors helps to measure micrometre displacements and small rotation angles. Advantages of this type of transducers are their simple design, high precision of processing, low costs and ability of a non-contact measurement. The study shows an analysis of a fibre-optic intensity sensor used for MEMS movable structure rotation angle measurement. An intensity of the light in the photodetector is basically dependent on a distance between a reflecting surface and a head surface of the fibre transmitting arm, and the deflection angle. Experimental tests were made for PMMA 980/1000 plastic fibres, Θ NA =33°. The study shows both analytical and practical results. It proves that calculated and experimental characteristics for the analysed transducers are similar.

Estimating Elevation Angles From SAR Crosstalk

Science.gov (United States)

Freeman, Anthony

1994-01-01

Scheme for processing polarimetric synthetic-aperture-radar (SAR) image data yields estimates of elevation angles along radar beam to target resolution cells. By use of estimated elevation angles, measured distances along radar beam to targets (slant ranges), and measured altitude of aircraft carrying SAR equipment, one can estimate height of target terrain in each resolution cell. Monopulselike scheme yields low-resolution topographical data.

Gaugings at angles from orientifold reductions

International Nuclear Information System (INIS)

Roest, Diederik

2009-01-01

We consider orientifold reductions to N= 4 gauged supergravity in four dimensions. A special feature of this theory is that different factors of the gauge group can have relative angles with respect to the electro-magnetic SL(2) symmetry. These are crucial for moduli stabilization and de Sitter vacua. We show how such gaugings at angles generically arise in orientifold reductions.

Practical evaluation of action-angle variables

International Nuclear Information System (INIS)

Boozer, A.H.

1984-02-01

A practical method is described for establishing action-angle variables for a Hamiltonian system. That is, a given nearly integrable Hamiltonian is divided into an exactly integrable system plus a perturbation in action-angle form. The transformation of variables, which is carried out using a few short trajectory integrations, permits a rapid determination of trajectory properties throughout a phase space volume

Glancing angle x-ray studies of oxide films

International Nuclear Information System (INIS)

Davenport, A.J.; Isaacs, H.S.

1989-01-01

High brightness synchrotron radiation incident at glancing angles has been used to study inhibiting species present in low concentrations in oxide films on aluminum. Glancing incident angle fluorescence measurements give surface-sensitive information on the valence state of elements from the shape of the x-ray absorption edge. Angle-resolved measurements show the depth distribution of the species present. 15 refs., 4 figs

Metasurface-based angle-selective multichannel acoustic refractor

Science.gov (United States)

Liu, Bingyi; Jiang, Yongyuan

2018-05-01

We theoretically study the angle-selective refractions of an impedance-matched acoustic gradient-index metasurface, which is integrated with a rigid bar array of a deep subwavelength period. An interesting refraction order appears under the all-angle incidence despite the existence of a critical angle, and notably, the odevity of the phase-discretization level apparently selects the transmitted diffraction orders. We utilize the strategy of multilayered media design to realize a three-channel acoustic refractor, which shows good promise for constructing multifunctional diffractive acoustic elements for acoustic communication.

Evaluation of the Anterior Segment Angle-to-Angle Scan of Cirrus High-Definition Optical Coherence Tomography and Comparison With Gonioscopy and With the Visante OCT.

Science.gov (United States)

Tun, Tin A; Baskaran, Mani; Tan, Shayne S; Perera, Shamira A; Aung, Tin; Husain, Rahat

2017-01-01

To evaluate the diagnostic performance of the anterior segment angle-to-angle scan of the Cirrus high-definition optical coherence tomography (HD-OCT) in detecting eyes with closed angles. All subjects underwent dark-room gonioscopy by an ophthalmologist. A technician performed anterior segment imaging with Cirrus (n = 202) and Visante OCT (n = 85) under dark-room conditions. All eyes were categorized by two masked graders as per number of closed quadrants. Each quadrant of anterior chamber angle was categorized as a closed angle if posterior trabecular meshwork could not be seen on gonioscopy or if there was any irido-corneal contact anterior to scleral spur in Cirrus and Visante images. An eye was graded as having a closed angle if two or more quadrants were closed. Agreement and area under the curve (AUC) were performed. There were 50 (24.8%) eyes with closed angles. The agreements of closed-angle diagnosis (by eye) between Cirrus HD-OCT and gonioscopy (k = 0.59; 95% confidence interval (CI) 0.45-0.72; AC1 = 0.76) and between Cirrus and Visante OCT (k = 0.65; 95% CI 0.48-0.82, AC1 = 0.77) were moderate. The AUC for diagnosing the eye with gonioscopic closed angle by Cirrus HD-OCT was good (AUC = 0.86; sensitivity = 83.33; specificity = 77.78). The diagnostic performance of Cirrus HD-OCT in detecting the eyes with closed angles was similar to that of Visante (AUC 0.87 vs. 0.9, respectively; P = 0.51). The anterior segment angle-to-angle scans of Cirrus HD-OCT demonstrated similar diagnostic performance as Visante in detecting gonioscopic closed angles. The agreement between Cirrus and gonioscopy for detecting eyes with closed angles was moderate.

Automatic Cobb Angle Determination From Radiographic Images

NARCIS (Netherlands)

Sardjono, Tri Arief; Wilkinson, Michael H. F.; Veldhuizen, Albert G.; van Ooijen, Peter M. A.; Purnama, Ketut E.; Verkerke, Gijsbertus J.

2013-01-01

Study Design. Automatic measurement of Cobb angle in patients with scoliosis. Objective. To test the accuracy of an automatic Cobb angle determination method from frontal radiographical images. Summary of Background Data. Thirty-six frontal radiographical images of patients with scoliosis. Methods.

[Anatomy of fractures of the inferior scapular angle].

Science.gov (United States)

Bartoníček, J; Tuček, M; Malík, J

2018-01-01

The aim of this study is to describe the anatomy of fractures of the inferior angle and the adjacent part of the scapular body, based on 3D CT reconstructions. In a series of 375 scapular fractures, we identified a total of 20 fractures of the inferior angle of the scapular body (13 men, 7 women), with a mean patient age of 50 years (range 3373). In all fractures, 3D CT reconstructions were obtained, allowing an objective evaluation of the fracture pattern with a focus on the size and shape of the inferior angle fragment, propagation of the fracture line to the lateral and medial borders of the infraspinous part of the scapular body, fragment displacement and any additional fracture of the ipsilateral scapula and the shoulder girdle. We identified a total of 5 types of fracture involving the distal half of the infraspinous part of the scapular body. The first type, recorded in 5 cases, affected only the apex of the inferior angle, with a small part of the adjacent medial border. The second type, occurring in 4 cases, involved fractures separating the entire inferior angle. The third type, represented by 4 cases, was characterized by a fracture line starting medially close above the inferior angle and passing proximolaterally. The separated fragment had a shape of a big drop, carrying also the distal half of the lateral pillar in addition to the inferior angle. In the fourth type identified in 5 fractures, the separated fragment was formed both by the inferior angle and a variable part of the medial border. The fifth type, being by its nature a transition to the fracture of the infraspinous part of the body, was recorded in 2 cases, with the same V-shaped fragment. Fractures of the inferior angle and the adjacent part of the scapular body are groups of fractures differing from other infraspinous fractures of the scapular body. Although these fractures are highly variable in terms of shape, they have the same course of fracture line and the manner of displacement

Sun-view angle effects on reflectance factors of corn canopies

Science.gov (United States)

Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.; Bauer, M. E.

1985-01-01

The effects of sun and view angles on reflectance factors of corn (Zea mays L.) canopies ranging from the six leaf stage to harvest maturity were studied on the Purdue University Agronomy Farm by a multiband radiometer. The two methods of acquiring spectral data, the truck system and the tower systrem, are described. The analysis of the spectral data is presented in three parts: solar angle effects on reflectance factors viewed at nadir; solar angle effects on reflectance factors viewed at a fixed sun angle; and both sun and view angles effect on reflectance factors. The analysis revealed that for nadir-viewed reflectance factors there is a strong solar angle dependence in all spectral bands for canopies with low leaf area index. Reflectance factors observed from the sun angle at different view azimuth angles showed that the position of the sensor relative to the sun is important in determining angular reflectance characteristics. For both sun and view angles, reflectance factors are maximized when the sensor view direction is towards the sun.

Effect of Angle of Attack on Slope Climbing Performance

Science.gov (United States)

Creager, Colin M.; Jones, Lucas; Smith, Lauren M.

2017-01-01

Ascending steep slopes is often a very difficult challenge for off-road vehicles, whether on Earth or on extraterrestrial bodies. This challenge is even greater if the surface consists of loose granular soil that does not provide much shear strength. This study investigated how the path at which a vehicle traverses a slope, specifically the angle that it is commanded to drive relative to the base of the hill (the angle of attack), can affect its performance. A vehicle was driven in loose sand at slope angles up to 15 degrees and angles of attack ranging from 10 to 90 degrees. A novel photogrammetry technique was implemented to both track vehicle motion and create a three-dimensional profile of the terrain. This allowed for true wheel sinkage measurements. The study showed that though low angles of attack result in lower wheel slip and sinkage, the efficiency of the vehicles uphill motion increased at higher angles of attack. For slopes up to 15 degrees, a 90 degree angle of attack provided the greatest likelihood of successful ascent.

Contact angle measurement with a smartphone.

Science.gov (United States)

Chen, H; Muros-Cobos, Jesus L; Amirfazli, A

2018-03-01

In this study, a smartphone-based contact angle measurement instrument was developed. Compared with the traditional measurement instruments, this instrument has the advantage of simplicity, compact size, and portability. An automatic contact point detection algorithm was developed to allow the instrument to correctly detect the drop contact points. Two different contact angle calculation methods, Young-Laplace and polynomial fitting methods, were implemented in this instrument. The performance of this instrument was tested first with ideal synthetic drop profiles. It was shown that the accuracy of the new system with ideal synthetic drop profiles can reach 0.01% with both Young-Laplace and polynomial fitting methods. Conducting experiments to measure both static and dynamic (advancing and receding) contact angles with the developed instrument, we found that the smartphone-based instrument can provide accurate and practical measurement results as the traditional commercial instruments. The successful demonstration of use of a smartphone (mobile phone) to conduct contact angle measurement is a significant advancement in the field as it breaks the dominate mold of use of a computer and a bench bound setup for such systems since their appearance in 1980s.

Contact angle measurement with a smartphone

Science.gov (United States)

Chen, H.; Muros-Cobos, Jesus L.; Amirfazli, A.

2018-03-01

In this study, a smartphone-based contact angle measurement instrument was developed. Compared with the traditional measurement instruments, this instrument has the advantage of simplicity, compact size, and portability. An automatic contact point detection algorithm was developed to allow the instrument to correctly detect the drop contact points. Two different contact angle calculation methods, Young-Laplace and polynomial fitting methods, were implemented in this instrument. The performance of this instrument was tested first with ideal synthetic drop profiles. It was shown that the accuracy of the new system with ideal synthetic drop profiles can reach 0.01% with both Young-Laplace and polynomial fitting methods. Conducting experiments to measure both static and dynamic (advancing and receding) contact angles with the developed instrument, we found that the smartphone-based instrument can provide accurate and practical measurement results as the traditional commercial instruments. The successful demonstration of use of a smartphone (mobile phone) to conduct contact angle measurement is a significant advancement in the field as it breaks the dominate mold of use of a computer and a bench bound setup for such systems since their appearance in 1980s.

Perturbative estimates of lepton mixing angles in unified models

International Nuclear Information System (INIS)

Antusch, Stefan; King, Stephen F.; Malinsky, Michal

2009-01-01

Many unified models predict two large neutrino mixing angles, with the charged lepton mixing angles being small and quark-like, and the neutrino masses being hierarchical. Assuming this, we present simple approximate analytic formulae giving the lepton mixing angles in terms of the underlying high energy neutrino mixing angles together with small perturbations due to both charged lepton corrections and renormalisation group (RG) effects, including also the effects of third family canonical normalization (CN). We apply the perturbative formulae to the ubiquitous case of tri-bimaximal neutrino mixing at the unification scale, in order to predict the theoretical corrections to mixing angle predictions and sum rule relations, and give a general discussion of all limiting cases. We also discuss the implications for the sum rule relations of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

Steering Angle Function Algorithm of Morphing of Residential Area

Directory of Open Access Journals (Sweden)

XIE Tian

2015-07-01

Full Text Available A residential area feature morphing method based on steering angle function is presented. To residential area with the same representation under two different scales,transforming the representation of the residential area polygon from vector coordinates to steering angle function,then using the steering angle function to match,and finding out the similarity and the differences between the residential areas under different scale to get the steering angle function of the the residential areas under any middle scale,the final,transforming the middle scale steering angle function to vector coordinates form,and get the middle shape interpolation of the the residential area polygon.Experimental results show:the residential area morphing method by using steering angle function presented can realize the continuous multi-scale representation under the premise of keeping in shape for the residential area with the rectangular boundary features.

Angle-selective all-dielectric Huygens’ metasurfaces

Science.gov (United States)

Arslan, D.; Chong, K. E.; Miroshnichenko, A. E.; Choi, D.-Y.; Neshev, D. N.; Pertsch, T.; Kivshar, Y. S.; Staude, I.

2017-11-01

We experimentally and numerically study the angularly resolved transmission properties of dielectric metasurfaces consisting of silicon nanodisks which support electric and magnetic dipolar Mie-type resonances in the near-infrared spectral range. First, we concentrate on Huygens’ metasurfaces which are characterised by a spectral overlap of the fundamental electric and magnetic dipole resonances of the silicon nanodisks at normal incidence. Huygens’ metasurfaces exhibit a high transmitted intensity over the spectral width of the resonances due to impedance matching, while the transmitted phase shows a variation of 2π as the wavelength is swept across the width of the resonances. We observe that the transmittance of the Huygens’ metasurfaces depends on the incidence angle and is sensitive to polarisation for non-normal incidence. As the incidence angle is increased starting from normal incidence, the two dipole resonances are shifted out of the spectral overlap and the resonant features appear as pronounced transmittance minima. Next, we consider a metasurface with an increased nanodisk radius as compared to the Huygens’ metasurface, which supports spectrally separate electric and magnetic dipole resonances at normal incidence. We show that for TM polarisation, we can shift the resonances of this metasurface into spectral overlap and regain the high resonant transmittance characteristic of Huygens’ metasurfaces at a particular incidence angle. Furthermore, both metasurfaces are demonstrated to reject all TM polarised light incident under angles other than the design overlap angle at their respective operation frequency. Our experimental observations are in good qualitative agreement with numerical calculations.

Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography.

Science.gov (United States)

Yeo, Joon Hyung; Moon, Nam Ju; Lee, Jeong Kyu

2017-06-01

To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device. © 2017 The Korean Ophthalmological Society

Dilemma of gonial angle measurement: Panoramic radiograph or lateral cephalogram

Energy Technology Data Exchange (ETDEWEB)

Radhakrishnan, Pillai Devu; Varma, Nilambur Kovilakam Sapna; Ajith, Vallikat Velath [Dept. of Orthodontics, Amrita School of Dentistry, Kochi (India)

2017-06-15

The purpose of this study was to evaluate the accuracy of panoramic imaging in measuring the right and left gonial angles by comparing the measured angles with the angles determined using a lateral cephalogram of adult patients with class I malocclusion. The gonial angles of 50 class I malocclusion patients (25 males and 25 females; mean age: 23 years) were measured using both a lateral cephalogram and a panoramic radiograph. In the lateral cephalograms, the gonial angle was measured at the point of intersection of the ramus plane and the mandibular plane. In the panoramic radiographs, the gonial angle was measured by drawing a line tangent to the lower border of the mandible and another line tangent to the distal border of the ascending ramus and the condyle on both sides. The data obtained from both radiographs were statistically compared. No statistically significant difference was observed between the gonial angle measured using the lateral cephalograms and that determined using the panoramic radiographs. Further, there was no statistically significant difference in the measured gonial angle with respect to gender. The results also showed a statistically insignificant difference in the mean of the right and the left gonial angles measured using the panoramic radiographs. As the gonial angle measurements using panoramic radiographs and lateral cephalograms showed no statistically significant difference, panoramic radiography can be considered in orthodontics for measuring the gonial angle without any interference due to superimposed images.

Flocking and invariance of velocity angles.

Science.gov (United States)

Liu, Le; Huang, Lihong; Wu, Jianhong

2016-04-01

Motsch and Tadmor considered an extended Cucker-Smale model to investigate the flocking behavior of self-organized systems of interacting species. In this extended model, a cone of the vision was introduced so that outside the cone the influence of one agent on the other is lost and hence the corresponding influence function takes the value zero. This creates a problem to apply the Motsch-Tadmor and Cucker-Smale method to prove the flocking property of the system. Here, we examine the variation of the velocity angles between two arbitrary agents, and obtain a monotonicity property for the maximum cone of velocity angles. This monotonicity permits us to utilize existing arguments to show the flocking property of the system under consideration, when the initial velocity angles satisfy some minor technical constraints.

Exclusive Backward-Angle Omega Meson Electroproduction

Energy Technology Data Exchange (ETDEWEB)

Wenliang, Li [Univ. of Regina, Regina, SK (Canada)

2017-10-01

Exclusive meson electroproduction at different squared four-momenta of the exchanged virtual photon, Q² , and at different four-momentum transfers, t and u, can be used to probe QCD's transition from hadronic degrees of freedom at the long distance scale to quark-gluon degrees of freedom at the short distance scale. Backward-angle meson electroproduction was previously ignored, but is anticipated to offer complimentary information to conventional forward-angle meson electroproduction studies on nucleon structure. This work is a pioneering study of backward-angle ω cross sections through the exclusive ¹H(e, e'p)ω reaction using the missing mass reconstruction technique. The extracted cross sections are separated into the transverse (T), longitudinal (L), and LT, TT interference terms. The analyzed data were part of experiment E01-004 (Fπ-2), which used 2.6-5.2 GeV electron beams and HMS+SOS spectrometers in Jefferson Lab Hall C. The primary objective was to detect coincidence π in the forward-angle, where the backward-angle omega events were fortuitously detected. The experiment has central Q² values of 1.60 and 2.45 GeV² , at W = 2.21 GeV. There was significant coverage in phi and epsilon, which allowed separation of σ_T,L,LT,TT . The data set has a unique u coverage of -u ~ 0, which corresponds to -t > 4 GeV² . The separated σ_T result suggest a flat ~ 1/Q^1.33±1.21 dependence, whereas sigma_L seems to hold a stronger 1/Q^9.43±6.28 dependence. The σL/σ_T ratio indicate σ_T dominance at Q² = 2.45 GeV² at the ~90% confidence level. After translating the results into the -t space of the published CLAS data, our data show evidence of a backward-angle omega electroproduction peak at both Q² settings. Previously, this phenomenon showing both forward and backward-angle peaks was only observed in the meson

Experimental Validation of the Invariance of Electrowetting Contact Angle Saturation

NARCIS (Netherlands)

Chevalliot, S.; Dhindsa, M.; Kuiper, S.; Heikenfeld, J.

2011-01-01

Basic electrowetting theory predicts that a continued increase in applied voltage will allow contact angle modulation to zero degrees. In practice, the effect of contact angle saturation has always been observed to limit the contact angle modulation, often only down to a contact angle of 60 to 70°.

LHC Report: playing with angles

CERN Multimedia

Mike Lamont for the LHC team

2016-01-01

Ready (after a machine development period), steady (running), go (for a special run)!   The crossing angles are an essential feature of the machine set-up. They have to be big enough to reduce the long-range beam-beam effect. The LHC has recently enjoyed a period of steady running and managed to set a new record for “Maximum Stable Luminosity Delivered in 7 days” of 3.29 fb-1 between 29 August and 4 September. The number of bunches per beam remains pegged at 2220 because of the limitations imposed by the SPS beam dump. The bunch population is also somewhat reduced due to outgassing near one of the injection kickers at point 8. Both limitations will be addressed during the year-end technical stop, opening the way for increased performance in 2017. On 10 and 11 September, a two day machine development (MD) period took place. The MD programme included a look at the possibility of reducing the crossing angle at the high-luminosity interaction points. The crossing angles are an ess...

Computing angle of arrival of radio signals

Science.gov (United States)

Borchardt, John J.; Steele, David K.

2017-11-07

Various technologies pertaining to computing angle of arrival of radio signals are described. A system that is configured for computing the angle of arrival of a radio signal includes a cylindrical sheath wrapped around a cylindrical object, where the cylindrical sheath acts as a ground plane. The system further includes a plurality of antennas that are positioned about an exterior surface of the cylindrical sheath, and receivers respectively coupled to the antennas. The receivers output measurements pertaining to the radio signal. A processing circuit receives the measurements and computes the angle of arrival of the radio signal based upon the measurements.

The quadriceps angle

DEFF Research Database (Denmark)

Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona

2012-01-01

: Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...

At Right Angles

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 9. At Right Angles. Shailesh A Shirali. Information and Announcements Volume 17 Issue 9 September 2012 pp 920-920. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/017/09/0920-0920 ...

Effect of MLC leaf position, collimator rotation angle, and gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma

Energy Technology Data Exchange (ETDEWEB)

Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Wei, Yuquan, E-mail: yuquawei@vip.sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)

2013-07-01

The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.

Use of EyeCam for imaging the anterior chamber angle.

Science.gov (United States)

Perera, Shamira A; Baskaran, Mani; Friedman, David S; Tun, Tin A; Htoon, Hla M; Kumar, Rajesh S; Aung, Tin

2010-06-01

To compare EyeCam (Clarity Medical Systems, Pleasanton, CA) imaging with gonioscopy for detecting angle closure. In this prospective, hospital-based study, subjects underwent gonioscopy by a single observer and EyeCam imaging by a different operator. EyeCam images were graded by two masked observers. The anterior chamber angle in a quadrant was classified as closed if the trabecular meshwork could not be seen. The eye was classified as having angle closure if two or more quadrants were closed. One hundred fifty-two subjects were studied. The mean age was 57.4 years (SD 12.9) and there were 82 (54%) men. Of the 152 eyes, 21 (13.8%) had angle closure. The EyeCam provided clear images of the angles in 98.8% of subjects. The agreement between the EyeCam and gonioscopy for detecting angle closure in the superior, inferior, nasal, and temporal quadrants based on agreement coefficient (AC1) statistics was 0.73, 0.75, 0.76, and 0.72, respectively. EyeCam detected more closed angles than did gonioscopy in all quadrants (P gonioscopy, 21/152 (13.8%) eyes were diagnosed as angle closure compared to 41 (27.0%) of 152 with EyeCam (P gonioscopy for detecting angle closure. However, it detected more closed angles than did gonioscopy in all quadrants.

Association of lens vault with narrow angles among different ethnic groups.

Science.gov (United States)

Lee, Roland Y; Huang, Guofu; Cui, Qi N; He, Mingguang; Porco, Travis C; Lin, Shan C

2012-06-01

To compare lens vault between open-angle and narrow-angle eyes in African-, Caucasian-, Hispanic-, Chinese- and Filipino-Americans. In this prospective study, 436 patients with open angle and narrow angle based on the Shaffer gonioscopic grading classification underwent anterior-segment optical coherence tomography. The Zhongshan Angle Assessment Program was used to calculate lens vault. The narrow-angle group included 32 Chinese-Americans, 22 Filipino-Americans, 26 African-Americans, 24 Hispanic-Americans and 73 Caucasian-Americans. The open-angle group included 56 Chinese-Americans, 29 Filipino-Americans, 45 African-Americans, 27 Hispanic-Americans and 102 Caucasian-Americans. Linear mixed effect regression models, accounting for the use of both eyes and adjusting for age, sex, pupil diameter and spherical equivalent, were used to test for the ethnicity and angle coefficients. Tukey's multiple comparison test was used for pairwise comparisons among the open-angle racial groups. Significant difference in lens vault was found among the open-angle racial groups (P = 0.022). For the open-angle patients, mean values for the lens vault measurements were 265 ± 288 µm for Chinese-Americans, 431 ± 248 µm for Caucasian-Americans, 302 ± 213 µm for Filipino-Americans, 304 ± 263 µm for Hispanic-Americans and 200 ± 237 µm for African-Americans. Using Tukey's multiple comparison for pairwise comparisons among the open-angle racial groups, a significant difference was found between African-American and Caucasian-Americans groups (P values for the rest of the pairwise comparisons were not statistically significant. No significant difference was found among the narrow-angle racial groups (P = 0.14). Comparison between the open angle and narrow angle within each racial group revealed significant difference for all racial groups (P < 0.05). Among all the ethnicities included in this study, narrow-angle eyes have greater lens vault compared to open-angle

The influence of erupting lateral teeth on maxillary anterior crowding in two Angle Class I maloclussion cases with high and low angles

Directory of Open Access Journals (Sweden)

Hiroshi Ueda

2016-01-01

Full Text Available Two cases of anterior crowding, both Skeletal Class I and Angle Class I maloclussion, one being low angle and the other high angle respectively, respectively, were treated and evaluated to ascertain whether or not there is a relationship among disproportionate mesial axial angulation of the maxillary lateral teeth and the Frankfurt Horizontal-Functional Occlusal plane, therefore generating maxillary anterior crowding. Both cases were Japanese boys, the first one aged 9 years 10 months with chief complaint being anterior crowding and the second case aged 7 years and 8 months complaining of inadequate space for satisfying canine eruption. During and after the second stage of orthodontic treatment on both cases, several radiographic analysis were performed to assess treatment progress and retention; from these radiographs, it was noticed among other findings that in the high-angle case, the axial angulations of the maxillary lateral incisors were markedly smaller than in the low-angle case, thus indicating mesial tipping in the upper dental arch. This decreased mesial axial angulation of the lateral teeth observed at high angles may potentially cause maxillary space deficiency.

Contact angle and local wetting at contact line.

Science.gov (United States)

Li, Ri; Shan, Yanguang

2012-11-06

This theoretical study was motivated by recent experiments and theoretical work that had suggested the dependence of the static contact angle on the local wetting at the triple-phase contact line. We revisit this topic because the static contact angle as a local wetting parameter is still not widely understood and clearly known. To further clarify the relationship of the static contact angle with wetting, two approaches are applied to derive a general equation for the static contact angle of a droplet on a composite surface composed of heterogeneous components. A global approach based on the free surface energy of a thermodynamic system containing the droplet and solid surface shows the static contact angle as a function of local surface chemistry and local wetting state at the contact line. A local approach, in which only local forces acting on the contact line are considered, results in the same equation. The fact that the local approach agrees with the global approach further demonstrates the static contact angle as a local wetting parameter. Additionally, the study also suggests that the wetting described by the Wenzel and Cassie equations is also the local wetting of the contact line rather than the global wetting of the droplet.

Polarized Line Formation in Arbitrary Strength Magnetic Fields Angle-averaged and Angle-dependent Partial Frequency Redistribution

Energy Technology Data Exchange (ETDEWEB)

Sampoorna, M.; Nagendra, K. N. [Indian Institute of Astrophysics, Koramangala, Bengaluru 560 034 (India); Stenflo, J. O., E-mail: sampoorna@iiap.res.in, E-mail: knn@iiap.res.in, E-mail: stenflo@astro.phys.ethz.ch [Institute of Astronomy, ETH Zurich, CH-8093 Zurich (Switzerland)

2017-08-01

Magnetic fields in the solar atmosphere leave their fingerprints in the polarized spectrum of the Sun via the Hanle and Zeeman effects. While the Hanle and Zeeman effects dominate, respectively, in the weak and strong field regimes, both these effects jointly operate in the intermediate field strength regime. Therefore, it is necessary to solve the polarized line transfer equation, including the combined influence of Hanle and Zeeman effects. Furthermore, it is required to take into account the effects of partial frequency redistribution (PRD) in scattering when dealing with strong chromospheric lines with broad damping wings. In this paper, we present a numerical method to solve the problem of polarized PRD line formation in magnetic fields of arbitrary strength and orientation. This numerical method is based on the concept of operator perturbation. For our studies, we consider a two-level atom model without hyperfine structure and lower-level polarization. We compare the PRD idealization of angle-averaged Hanle–Zeeman redistribution matrices with the full treatment of angle-dependent PRD, to indicate when the idealized treatment is inadequate and what kind of polarization effects are specific to angle-dependent PRD. Because the angle-dependent treatment is presently computationally prohibitive when applied to realistic model atmospheres, we present the computed emergent Stokes profiles for a range of magnetic fields, with the assumption of an isothermal one-dimensional medium.

Optimal tilt-angles for solar collectors used in China

International Nuclear Information System (INIS)

Tang Runsheng; Wu Tong

2004-01-01

A reasonable estimation of the optimal tilt angle of a fixed collector for maximizing its energy collection must be done based on the monthly global and diffuse radiation on a horizontal surface. However, the monthly diffuse radiation is not always available in many places. In this paper, a simple mathematical procedure for the estimation of the optimal tilt angle of a collector is presented based on the monthly horizontal radiation. A comparison of the optimal tilt angles of collectors obtained from expected monthly diffuse radiation and that from the actual monthly diffuse radiation showed that this method gives a good estimation of the optimal tilt angle, except for places with a considerably lower clearness index. A contour map of the optimal tilt angle of the south-facing collectors used for the entire year in China is also outlined, based on monthly horizontal radiation of 152 places around the country, combing the optimal tilt angle of another 30 cities based on the actual monthly diffuse radiation

Calcaneal Fractures and Böhler’s Angle

Directory of Open Access Journals (Sweden)

Lindsey Spiegelman

2017-01-01

Full Text Available History of present illness: 40-year-old male presents to the emergency department after falling off a ladder. He was repairing a window when he fell, landing on the ground 12 feet below. The patient landed onto his feet bilaterally and then fell backwards onto his buttocks. On arrival, the patient had bilateral foot pain. He denied any back pain, headache, or loss of consciousness. Significant findings: The right ankle lateral radiograph shows a comminuted, non-displaced fracture of the posterior calcaneus (red arrow in addition to fracture fragments along the heel pad margin (blue arrow. The left ankle lateral radiograph shows a displaced, comminuted fracture of the mid to posterior calcaneus with extension into the subtalar joint posteriorly (purple arrow. There is subcutaneous air seen anteriorly to the tibiotalar joint space (green arrow in addition to a joint effusion. Of note, the Böhler’s angle in the left x-ray is 16 degrees which is consistent with a fracture (see red annotation showing Böhler’s angle. Discussion: Calcaneal fractures occur typically in adults who have undergone significant axial load on their feet secondary to a fall from high height.2,3 There are two broad types of calcaneal fractures: intraarticular and extraarticular.2 The intraarticular fractures are colloquially referred to as a “Lover’s Fracture” as they have been known to occur in those jumping out of a tall window to escape the wrath of a lover’s spouse.1 Calcaneal fractures are best diagnosed with a CT scan or with lateral x-ray by measuring Böhler’s angle.2,3 This is the angle formed by the intersection of two lines demonstrated on a normal lateral ankle radiograph. The first line is drawn between the superior aspect of the anterior process of the calcaneus (point A and the superior edge of the posterior articular facet (point B. The second line is drawn between the superior aspect of the posterior calcaneal tuberosity (point C and point B.2

Rotating Shaft Tilt Angle Measurement Using an Inclinometer

OpenAIRE

Luo Jun; Wang Zhiqian; Shen Chengwu; Wen Zhuoman; Liu Shaojin; Cai Sheng; Li Jianrong

2015-01-01

This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendic...

Predictors of Intraocular Pressure After Phacoemulsification in Primary Open-Angle Glaucoma Eyes with Wide Versus Narrower Angles (An American Ophthalmological Society Thesis).

Science.gov (United States)

Lin, Shan C; Masis, Marisse; Porco, Travis C; Pasquale, Louis R

2017-08-01

To assess if narrower-angle status and anterior segment optical coherence tomography (AS-OCT) parameters can predict intraocular pressure (IOP) drop in primary open-angle glaucoma (POAG) patients after cataract surgery. This was a prospective case series of consecutive cataract surgery patients with POAG and no peripheral anterior synechiae (PAS) using a standardized postoperative management protocol. Preoperatively, patients underwent gonioscopy and AS-OCT. The same glaucoma medication regimen was resumed by 1 month. Potential predictors of IOP reduction included narrower-angle status by gonioscopy and angle-opening distance (AOD500) as well as other AS-OCT parameters. Mixed-effects regression adjusted for use of both eyes and other potential confounders. We enrolled 66 eyes of 40 glaucoma patients. The IOP reduction at 1 year was 4.2±3 mm Hg (26%, P gonioscopy. By AOD500 classification, the narrower-angle group had 3.4±3 mm Hg (21%, P <.001) reduction vs 2.5±3 mm Hg (16%, P <.001) in the wide-angle group ( P =.031 for difference). When the entire cohort was assessed, iris thickness, iris area, and lens vault were correlated with increasing IOP reduction at 1 year ( P <.05 for all). In POAG eyes, cataract surgery lowered IOP to a greater degree in the narrower-angle group than in the wide-angle group, and parameters relating to iris thickness and area, as well as lens vault, were correlated with IOP reduction. These findings can guide ophthalmologists in their selection of cataract surgery as a potential management option.

Analyzing the installation angle error of a SAW torque sensor

International Nuclear Information System (INIS)

Fan, Yanping; Ji, Xiaojun; Cai, Ping

2014-01-01

When a torque is applied to a shaft, normal strain oriented at ±45° direction to the shaft axis is at its maximum, which requires two one-port SAW resonators to be bonded to the shaft at ±45° to the shaft axis. In order to make the SAW torque sensitivity high enough, the installation angle error of two SAW resonators must be confined within ±5° according to our design requirement. However, there are few studies devoted to the installation angle analysis of a SAW torque sensor presently and the angle error was usually obtained by a manual method. Hence, we propose an approximation method to analyze the angle error. First, according to the sensitive mechanism of the SAW device to torque, the SAW torque sensitivity is deduced based on the linear piezoelectric constitutive equation and the perturbation theory. Then, when a torque is applied to the tested shaft, the stress condition of two SAW resonators mounted with an angle deviating from ±45° to the shaft axis, is analyzed. The angle error is obtained by means of the torque sensitivities of two orthogonal SAW resonators. Finally, the torque measurement system is constructed and the loading and unloading experiments are performed twice. The torque sensitivities of two SAW resonators are obtained by applying average and least square method to the experimental results. Based on the derived angle error estimation function, the angle error is estimated about 3.447°, which is close to the actual angle error 2.915°. The difference between the estimated angle and the actual angle is discussed. The validity of the proposed angle error analysis method is testified to by the experimental results. (technical design note)

Patient-specific rhytidectomy: finding the angle of maximal rejuvenation.

Science.gov (United States)

Jacono, Andrew A; Ransom, Evan R

2012-09-01

Rhytidectomy is fundamentally an operation of tissue release and resuspension, although the manner and direction of suspension are subject to perpetual debate. The authors describe a method for identifying the angle of maximal rejuvenation during rhytidectomy and quantify the resulting angle and its relationship to patient age. Patients were prospectively enrolled; demographic data, history, and operative details were recorded. Rhytidectomies were performed by the senior author (AAJ). After complete elevation, the face-lift flap was rotated in a medially-based arc (0-90°) while attention was given to the submental area, jawline, and midface. The angle of maximal rejuvenation for each hemiface was identified as described, and the flap was resuspended. During redraping, measurements of vertical and horizontal skin excess were recorded in situ. The resulting angle of lift was then calculated for each hemiface using trigonometry. Symmetry between sides was determined, and the effect of patient age on this angle was assessed. Three hundred hemifaces were operated (147 women; 3 men). Mean age was 60 years (range, 37-80 years). Mean resulting angle for the cohort was 60° from horizontal (range, 46-77°). This was inversely correlated with patient age (r = -.3). Younger patients (<50 years, 64°) had a significantly more vertical angle than older patients (≥70 years, 56°; P < .0002). No significant intersubject difference was found between hemifaces (P = .53). The authors present a method for identifying the angle of maximal rejuvenation during rhytidectomy. This angle was more superior than posterior in all cases and is intimately related to patient age. Lasting results demand a detailed anatomical understanding and strict attention to the direction and degree of laxity.

High prevalence of narrow angles among Filipino-American patients.

Science.gov (United States)

Seider, Michael I; Sáles, Christopher S; Lee, Roland Y; Agadzi, Anthony K; Porco, Travis C; Weinreb, Robert N; Lin, Shan C

2011-03-01

To determine the prevalence of gonioscopically narrow anterior chamber angles in a Filipino-American clinic population. The records of 122 consecutive, new, self-declared Filipino-American patients examined in a comprehensive ophthalmology clinic in Vallejo, California were reviewed retrospectively. After exclusion, 222 eyes from 112 patients remained for analysis. Data were collected for anterior chamber angle grade as determined by gonioscopy (Shaffer system), age, sex, manifest refraction (spherical equivalent), intraocular pressure, and cup-to-disk ratio. Data from both eyes of patients were included and modeled using standard linear mixed-effects regression. As a comparison, data were also collected from a group of 30 consecutive White patients from the same clinic. After exclusion, 50 eyes from 25 White patients remained for comparison. At least 1 eye of 24% of Filipino-American patients had a narrow anterior chamber angle (Shaffer grade ≤ 2). Filipino-American angle grade significantly decreased with increasingly hyperopic refraction (P=0.007) and larger cup-to-disk ratio (P=0.038). Filipino-American women had significantly decreased angle grades compared with men (P=0.028), but angle grade did not vary by intraocular pressure or age (all, P≥ 0.059). Narrow anterior chamber angles are highly prevalent in Filipino-American patients in our clinic population.

Local beam angle optimization with linear programming and gradient search

International Nuclear Information System (INIS)

Craft, David

2007-01-01

The optimization of beam angles in IMRT planning is still an open problem, with literature focusing on heuristic strategies and exhaustive searches on discrete angle grids. We show how a beam angle set can be locally refined in a continuous manner using gradient-based optimization in the beam angle space. The gradient is derived using linear programming duality theory. Applying this local search to 100 random initial angle sets of a phantom pancreatic case demonstrates the method, and highlights the many-local-minima aspect of the BAO problem. Due to this function structure, we recommend a search strategy of a thorough global search followed by local refinement at promising beam angle sets. Extensions to nonlinear IMRT formulations are discussed. (note)

Effect of stifle angle on the magnitude of the tibial plateau angle measurement in dogs with intact and transected cranial cruciate ligament. A cadaveric study.

Science.gov (United States)

Aulakh, K S; Harper, T A M; Lanz, O I; Daniel, G B; Werre, S R

2011-01-01

To determine the effect of stifle angle on the magnitude of the radiographic tibial plateau angle (TPA) in normal and cranial cruciate ligament (CCL) -deficient stifles. Three pairs of canine cadaver hindlimbs from three skeletally mature dogs were positioned in a custom-made positioning device. A lateral radiograph of each specimen was obtained before and after transection of the CCL at four stifle angles (90°, 110°, 135° and 140-150° [i.e. maximum extension]), based on goniometric measurements. Four observers determined the radiographic TPA twice for each radiograph with a minimum of two days between each measurement. The radiographic TPA measurements in all specimens at different stifle angles with intact CCL and transected CCL were compared with mixed-model ANOVA. The effect of stifle angle, CCL transection, and interaction between the two on observer TPA measurement variability was also determined using the coefficient of variation. Tibial plateau angle was not statistically different in the stifle angles for either the intact or transected CCL. There was also no statistical difference for TPA between intact and transected CCL groups at each of the stifle angles. Stifle angle, CCL transection and interaction between the two did not have any significant effect for intra-observer and inter-observer variation. The angle of the stifle during radiography does not influence the magnitude of the TPA measurement as determined on true lateral radiographs of the stifle and tibia in cadaveric canine limbs.

Angle assessment by EyeCam, goniophotography, and gonioscopy.

Science.gov (United States)

Baskaran, Mani; Perera, Shamira A; Nongpiur, Monisha E; Tun, Tin A; Park, Judy; Kumar, Rajesh S; Friedman, David S; Aung, Tin

2012-09-01

To compare EyeCam (Clarity Medical Systems, Pleasanton, CA) and goniophotography in detecting angle closure, using gonioscopy as the reference standard. In this hospital-based, prospective, cross-sectional study, participants underwent gonioscopy by a single observer, and EyeCam imaging and goniophotography by different operators. The anterior chamber angle in a quadrant was classified as closed if the posterior trabecular meshwork could not be seen. A masked observer categorized the eyes as per the number of closed quadrants, and an eye was classified as having angle closure if there were 2 or more quadrants of closure. Agreement between the methods was analyzed by κ statistic and comparison of area under receiver operating characteristic curves (AUC). Eighty-five participants (85 eyes) were included, the majority of whom were Chinese. Angle closure was detected in 38 eyes (45%) with gonioscopy, 40 eyes (47%) using EyeCam, and 40 eyes (47%) with goniophotography (P=0.69 in both comparisons, McNemar test). The agreement for angle closure diagnosis (by eye) between gonioscopy and the 2 imaging modalities was high (κ=0.86; 95% Confidence Interval (CI), 0.75-0.97), whereas the agreement between EyeCam and goniophotography was not as good (κ=0.72; 95% CI, 0.57-0.87); largely due to lack of agreement in the nasal and temporal quadrants (κ=0.55 to 0.67). The AUC for detecting eyes with gonioscopic angle closure was similar for goniophotography and EyeCam (AUC 0.93, sensitivity=94.7%, specificity=91.5%; P>0.95). EyeCam and goniophotography have similarly high sensitivity and specificity for the detection of gonioscopic angle closure.

Optimum tilt angle and orientation for solar collectors in Syria

International Nuclear Information System (INIS)

Skeiker, Kamal

2009-01-01

One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle) for the solar collector in the main Syrian zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of approximately 30% more than the case of a solar collector fixed on a horizontal surface.

Influence of Different Diffuser Angle on Sedan's Aerodynamic Characteristics

Science.gov (United States)

Hu, Xingjun; Zhang, Rui; Ye, Jian; Yan, Xu; Zhao, Zhiming

The aerodynamic characteristics have a great influence on the fuel economics and the steering stability of a high speed vehicle. The underbody rear diffuser is one of important aerodynamic add-on devices. The parameters of the diffuser, including the diffuser angle, the number and the shape of separators, the shape of the end plate and etc, will affect the underbody flow and the wake. Here, just the influence of the diffuser angle was investigated without separator and the end plate. The method of Computational Fluid Dynamics was adopted to study the aerodynamic characteristics of a simplified sedan with a different diffuser angle respectively. The diffuser angle was set to 0°, 3°, 6°, 9.8° and 12° respectively. The diffuser angle of the original model is 9.8°. The conclusions were drawn that when the diffuser angle increases, the underbody flow and especially the wake change greatly and the pressure change correspondingly; as a result, the total aerodynamic drag coefficients of car first decrease and then increases, while the total aerodynamic lift coefficients decrease.

Expressions for the Total Yaw Angle

Science.gov (United States)

2016-09-01

1. Introduction 1 2. Mathematical Notation 1 3. Total Yaw Expression Derivations 2 3.1 First Derivation 2 3.2 Second Derivation 4 3.3 Other...4 iv Approved for public release; distribution is unlimited. 1. Introduction The total yaw angle, γt , of a ballistic projectile is... elevation angles from spherical coordinates.∗ We again place point A at the end point of V. Now imagine a plane parallel to the y-z plane that includes

Angle-specific transparent conducting electrodes with metallic gratings

Energy Technology Data Exchange (ETDEWEB)

Rivolta, N. X. A., E-mail: nicolas.rivolta@umons.ac.be; Maes, B. [Micro- and Nanophotonic Materials Group, Faculty of Science, University of Mons, Avenue Maistriau 19, B-7000 Mons (Belgium)

2014-08-07

Transparent conducting electrodes, which are not made from indium tin oxide, and which display a strong angular dependence are useful for various technologies. Here, we introduce a tilted silver grating that combines a large conductance with a strong and angle-specific transmittance. When the light incidence angle matches the tilt angle of the grating, transmittance is close to the maximum along a very broadband range. We explain the behavior through simulations that show in detail the plasmonic and interference effects at play.

Asymmetric-cut variable-incident-angle monochromator.

Science.gov (United States)

Smither, R K; Graber, T J; Fernandez, P B; Mills, D M

2012-03-01

A novel asymmetric-cut variable-incident-angle monochromator was constructed and tested in 1997 at the Advanced Photon Source of Argonne National Laboratory. The monochromator was originally designed as a high heat load monochromator capable of handling 5-10 kW beams from a wiggler source. This was accomplished by spreading the x-ray beam out on the surface an asymmetric-cut crystal and by using liquid metal cooling of the first crystal. The monochromator turned out to be a highly versatile monochromator that could perform many different types of experiments. The monochromator consisted of two 18° asymmetrically cut Si crystals that could be rotated about 3 independent axes. The first stage (Φ) rotates the crystal around an axis perpendicular to the diffraction plane. This rotation changes the angle of the incident beam with the surface of the crystal without changing the Bragg angle. The second rotation (Ψ) is perpendicular to the first and is used to control the shape of the beam footprint on the crystal. The third rotation (Θ) controls the Bragg angle. Besides the high heat load application, the use of asymmetrically cut crystals allows one to increase or decrease the acceptance angle for crystal diffraction of a monochromatic x-ray beam and allows one to increase or decrease the wavelength bandwidth of the diffraction of a continuum source like a bending-magnet beam or a normal x-ray-tube source. When the monochromator is used in the doubly expanding mode, it is possible to expand the vertical size of the double-diffracted beam by a factor of 10-15. When this was combined with a bending magnet source, it was possible to generate an 8 keV area beam, 16 mm wide by 26 mm high with a uniform intensity and parallel to 1.2 arc sec that could be applied in imaging experiments.

Preferred viewing distance and screen angle of electronic paper displays.

Science.gov (United States)

Shieh, Kong-King; Lee, Der-Song

2007-09-01

This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and screen angle were 495 mm and 123.7 degrees. The mean viewing distances for Kolin Chlorestic Liquid Crystal display was 500 mm, significantly longer than Sony electronic ink display, 491 mm. Screen angle for Kolin was 127.4 degrees, significantly greater than that of Sony, 120.0 degrees. Various light sources revealed no significant effect on viewing distances; nevertheless, they showed significant effect on screen angles. The screen angle for sunlight lamp (D65) was similar to that of fluorescent lamp (TL84), but greater than that of tungsten lamp (F). Ambient illumination and E-paper type had significant effects on viewing distance and screen angle. The higher the ambient illumination was, the longer the viewing distance and the lesser the screen angle. Character size had significant effect on viewing distances: the larger the character size, the longer the viewing distance. The results of this study indicated that the viewing distance for E-Paper was similar to that of visual display terminal (VDT) at around 500 mm, but greater than normal paper at about 360 mm. The mean screen angle was around 123.7 degrees, which in terms of viewing angle is 29.5 degrees below horizontal eye level. This result is similar to the general suggested viewing angle between 20 degrees and 50 degrees below the horizontal line of sight.

Tibial and fibular angles in homozygous sickle cell disease

International Nuclear Information System (INIS)

Akamaguna, A.I.; Odita, J.C.; Ugbodaga, C.I.; Okafor, L.A.

1986-01-01

Measurements of the tibial and fibular angles made on ankle radiographs of 34 patients with sickle cell disease were compared with those of 36 normal Nigerians. Widening of the fibular angle, which is an indication of tibiotalar slant, was demonstrated in about 79% of sickle cell disease patients. By using fibular angle measurements as an objective method of assessing subtle tibiotalar slant, it is concluded that the incidence of this deformity is much higher among sickle cell disease patients than previously reported. The mean values of tibial and fibular angles in normal Nigerians are higher than has been reported amongst Caucasians. (orig.)

Primary angle closure glaucoma in a myopic kinship.

Science.gov (United States)

Hagan, J C; Lederer, C M

1985-03-01

Three related myopic individuals with primary angle closure glaucoma are reported. They had true myopia and not pseudomyopia secondary to increased lenticular index of refraction. We believe one of these individuals (-8.62 spherical equivalent) to have the most myopic case of primary angle closure glaucoma reported in the literature. Although myopia is associated with anatomical factors that offer considerable protection from primary angle closure glaucoma, its presence does not eliminate the possibility of this disease. Laser iridectomy was effective in the treatment of these patients.

Preoperative Navigated Transcranial Magnetic Stimulation and Tractography to Guide Endoscopic Cystoventriculostomy: A Technical Note and Case Report.

Science.gov (United States)

Hendrix, Philipp; Senger, Sebastian; Griessenauer, Christoph J; Simgen, Andreas; Linsler, Stefan; Oertel, Joachim

2018-01-01

To report a technique for endoscopic cystoventriculostomy guided by preoperative navigated transcranial magnetic stimulation (nTMS) and tractography in a patient with a large speech eloquent arachnoid cyst. A 74-year old woman presented with a seizure and subsequent persistent anomic aphasia from a progressive left-sided parietal arachnoid cyst. An endoscopic cystoventriculostomy and endoscope-assisted ventricle catheter placement were performed. Surgery was guided by preoperative nTMS and tractography to avoid eloquent language, motor, and visual pathways. Preoperative nTMS motor and language mapping were used to guide tractography of motor and language white matter tracts. The ideal locations of entry point and cystoventriculostomy as well as trajectory for stent-placement were determined preoperatively with a pseudo-3-dimensional model visualizing eloquent language, motor, and visual cortical and subcortical information. The early postoperative course was uneventful. At her 3-month follow-up visit, her language impairments had completely recovered. Additionally, magnetic resonance imaging demonstrated complete collapse of the arachnoid cyst. The combination of nTMS and tractography supports the identification of a safe trajectory for cystoventriculostomy in eloquent arachnoid cysts. Copyright © 2017 Elsevier Inc. All rights reserved.

Imaging and outcome in severe complications of lumbar epidural anaesthesia: report of 16 cases

Energy Technology Data Exchange (ETDEWEB)

Chiapparini, L.; Savoiardo, M. [Department of Neuroradiology, Istituto Nazionale Neurologico, Milano (Italy); Sghirlanzoni, A.; Pareyson, D. [Department of Neurology, Istituto Nazionale Neurologico, Milano (Italy)

2000-08-01

We reviewed the clinical and neuroradiological features in 16 patients with serious neurological complications of lumbar epidural anaesthesia. We observed acute, transient or permanent and delayed complications. Four patients had symptoms immediately after the procedure. One patient developed a subacute flaccid paraparesis. Two other patients had infectious spondylodiscitis at lumbar puncture level. Eight patients had a delayed progressive spastic paraparesis and were found to have subarachnoid cysts and irregularities of the surface of the spinal cord consistent with arachnoiditis; six of them had an extensive, complex syrinx within the cord. One patient had a severe lumbar polyradiculopathy, and MRI showed adhesive arachnoiditis involving the cauda equina. Although epidural anaesthesia is generally considered safe, rare but severe complications, such as radiculopathy, infectious disease, myelopathy from ischemia and arachnoiditis with a syrinx may occur. The patients with arachnoiditis had a relentless progression of the disease and a poor outcome: five are confined to a wheelchair, one is bedridden. Complications of epidural anaesthesia are easily recognised when they develop immediately; their relationship to the anaesthesia may be ignored or underestimated when they appear after a delay. Awareness of the possibility of delayed complications is important. (orig.)

Imaging and outcome in severe complications of lumbar epidural anaesthesia: report of 16 cases

International Nuclear Information System (INIS)

Chiapparini, L.; Savoiardo, M.; Sghirlanzoni, A.; Pareyson, D.

2000-01-01

We reviewed the clinical and neuroradiological features in 16 patients with serious neurological complications of lumbar epidural anaesthesia. We observed acute, transient or permanent and delayed complications. Four patients had symptoms immediately after the procedure. One patient developed a subacute flaccid paraparesis. Two other patients had infectious spondylodiscitis at lumbar puncture level. Eight patients had a delayed progressive spastic paraparesis and were found to have subarachnoid cysts and irregularities of the surface of the spinal cord consistent with arachnoiditis; six of them had an extensive, complex syrinx within the cord. One patient had a severe lumbar polyradiculopathy, and MRI showed adhesive arachnoiditis involving the cauda equina. Although epidural anaesthesia is generally considered safe, rare but severe complications, such as radiculopathy, infectious disease, myelopathy from ischemia and arachnoiditis with a syrinx may occur. The patients with arachnoiditis had a relentless progression of the disease and a poor outcome: five are confined to a wheelchair, one is bedridden. Complications of epidural anaesthesia are easily recognised when they develop immediately; their relationship to the anaesthesia may be ignored or underestimated when they appear after a delay. Awareness of the possibility of delayed complications is important. (orig.)

Evaluation of anterior chamber angle under dark and light conditions in angle closure glaucoma: An anterior segment OCT study.

Science.gov (United States)

Masoodi, Habibeh; Jafarzadehpur, Ebrahim; Esmaeili, Alireza; Abolbashari, Fereshteh; Ahmadi Hosseini, Seyed Mahdi

2014-08-01

To evaluate changes of nasal and temporal anterior chamber angle (ACA) in subjects with angle closure glaucoma using Spectralis AS-OCT (SAS-OCT) under dark and light conditions. Based on dark-room gonioscopy, 24 subjects with open angles and 86 with narrow angles participated in this study. The nasal and temporal angle opening distance at 500 μm anterior to the scleral spur (AOD500), nasal and temporal ACA were measured using SAS-OCT in light and dark conditions. In 2 groups, ACA and AOD500 in nasal and temporal quadrants were significantly greater in light compared to dark (all with p=0.000). The AOD500 and ACA were significantly higher in nasal than temporal in measured conditions for 2 groups except the ACA and AOD500 of normal group measured in light. The difference between nasal and temporal in dark (29.07 ± 65.71 μm for AOD500 and 5.7 ± 4.07° for ACA) was greater than light (24.86 ± 79.85 μm for AOD500 and 2.09 ± 7.21° for ACA) condition. But the difference was only significant for ACA (p=0.000). The correlation analysis showed a negative correlation between AOD500 and pupil diameter in temporal and nasal quadrants (both with p=0.000). While temporal AOD500 difference correlated with spherical equivalent, temporal and asal gonioscopy, nasal AOD correlated with IOP, temporal and nasal gonioscopy. Clinically important changes in ACA structure could be detected with SAS-OCT in nasal and temporal quadrants under different illumination intensity. The results could help in improvement of examination condition for better and more accurate assessment of individuals with angle closure glaucoma. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Acute necrosis after Gamma Knife surgery in vestibular schwannoma leading to multiple cranial nerve palsies.

Science.gov (United States)

Kapitza, Sandra; Pangalu, Athina; Horstmann, Gerhard A; van Eck, Albert T; Regli, Luca; Tarnutzer, Alexander A

2016-08-01

We discuss a rare acute complication after Gamma Knife therapy (Elekta AB, Stockholm, Sweden) in a single patient. A 52-year-old woman presented with vertigo, facial weakness and hearing loss emerging 48hours following Gamma Knife radiosurgery for a right-sided vestibular schwannoma. Neurological examination 6days after symptom onset showed right-sided facial palsy, spontaneous left-beating nystagmus and pathologic head-impulse testing to the right. Pure-tone audiogram revealed right-sided sensorineural hearing loss. A diagnosis of acute vestibulocochlear and facial neuropathy was made. Brain MRI demonstrated focal contrast sparing within the schwannoma, likely related to acute radiation necrosis. Acute multiple cranial neuropathies of the cerebellopontine angle after Gamma Knife treatment should raise suspicion of acute tissue damage within the schwannoma and should result in urgent MRI. Treatment with steroids may be considered based on accompanying swelling and edema. Copyright © 2016 Elsevier Ltd. All rights reserved.

MRI-based diagnostic imaging of the intratemporal facial nerve

International Nuclear Information System (INIS)

Kress, B.; Baehren, W.

2001-01-01

Detailed imaging of the five sections of the full intratemporal course of the facial nerve can be achieved by MRI and using thin tomographic section techniques and surface coils. Contrast media are required for tomographic imaging of pathological processes. Established methods are available for diagnostic evaluation of cerebellopontine angle tumors and chronic Bell's palsy, as well as hemifacial spasms. A method still under discussion is MRI for diagnostic evaluation of Bell's palsy in the presence of fractures of the petrous bone, when blood volumes in the petrous bone make evaluation even more difficult. MRI-based diagnostic evaluation of the idiopatic facial paralysis currently is subject to change. Its usual application cannot be recommended for routine evaluation at present. However, a quantitative analysis of contrast medium uptake of the nerve may be an approach to improve the prognostic value of MRI in acute phases of Bell's palsy. (orig./CB) [de

An Eustachian Tube Neuroendocrine Carcinoma: A Previously Undescribed Entity and Review of the Literature

Directory of Open Access Journals (Sweden)

Gavin J. le Nobel

2016-01-01

Full Text Available Primary sinonasal and middle ear neuroendocrine carcinomas are rare malignancies of the head and neck. Owing to the rarity of these tumors, the clinical behavior and optimal management of these tumors are not well defined. We present a case of an incidentally discovered sinonasal neuroendocrine carcinoma that was found to originate from the Eustachian tube, which has not previously been described in the literature. This patient was treated with primary surgical resection using a combination of transnasal and transaural approaches and achieved an incomplete resection. Follow-up imaging demonstrated continued tumor growth in the Eustachian tube as well as a new growth in the ipsilateral cerebellopontine angle and findings suspicious of perineural invasion. However, the tumor exhibited a benign growth pattern and despite continued growth the patient did not receive additional treatment and he remains asymptomatic 35 months following his original surgery.

A case of early recurred tentorial meningioma after subtotal removal and postoperative radiation

International Nuclear Information System (INIS)

Kim, Han Sik; Kim, Young Baeg; Kim, Mi Kyung; Hwang, Sung Nam; Suk, Jong Sik; Choi, Duck Young

1995-01-01

Postoperative radiation has been given to prevent or delay recurrence of subtotally resected meningioma in recent years. However, the authors experienced early recurred tentorial meningioma 10 months after subtotal resection and postoperative radiation. This 70-year-old man was found to have a large stradling mass on the left petrous pyramid, extending to the middle fossa and cerebellopontine angle(CPA). A subtotal resection was performed at initial surgery, remaining some residual tumor along the lateral tentorium and he received 5580 Gy of radiation over the following 5 weeks. He did well until 10 months after the irradiation, when he presented with left mastoid pain, facial palsy, and left hearing loss. MRI confirmed recurrence of tumor and gross total tumor resection was performed via presigmoid retrolabyrinthine approach. The histology of the recurrent tumor was basically identical with that of the primary lesion, except for the slightly increased celluarity and mild pleomorphism

Partially thrombosed giant aneurysm arising from a distal anterior inferior cerebellar artery–posterior inferior cerebellar artery variant: A case report

Directory of Open Access Journals (Sweden)

Hidetoshi Ooigawa

2015-09-01

Full Text Available Anterior inferior cerebellar artery (AICA–posterior inferior cerebellar artery (PICA is a well-known variant in cerebral arteries. However, aneurysms located on the variant are rare and a giant one has not been reported. We report a case of a partially thrombosed giant aneurysm arising from an AICA–PICA variant. The patient was a 42-year-old man who presented with right hearing loss and facial numbness associated with left hemidysesthesia. Magnetic resonance imaging revealed an approximately 3.0-cm mass lesion at the right cerebello-pontine angle (CPA. Angiography showed a partially thrombosed aneurysm arising from the right AICA–PICA. The aneurysm was treated with endovascular trapping and surgical thrombectomy. Although cerebral aneurysm is known to occur at this site, this case provides awareness, that manifestations of aneurysms in the CPA include progressive multiple cranial nerve palsies and sensory disturbance caused by brainstem compression.

Protein profiling reveals inter-individual protein homogeneity of arachnoid cyst fluid and high qualitative similarity to cerebrospinal fluid

Directory of Open Access Journals (Sweden)

Berle Magnus

2011-05-01

Full Text Available Abstract Background The mechanisms behind formation and filling of intracranial arachnoid cysts (AC are poorly understood. The aim of this study was to evaluate AC fluid by proteomics to gain further knowledge about ACs. Two goals were set: 1 Comparison of AC fluid from individual patients to determine whether or not temporal AC is a homogenous condition; and 2 Evaluate the protein content of a pool of AC fluid from several patients and qualitatively compare this with published protein lists of cerebrospinal fluid (CSF and plasma. Methods AC fluid from 15 patients with temporal AC was included in this study. In the AC protein comparison experiment, AC fluid from 14 patients was digested, analyzed by LC-MS/MS using a semi-quantitative label-free approach and the data were compared by principal component analysis (PCA to gain knowledge of protein homogeneity of AC. In the AC proteome evaluation experiment, AC fluid from 11 patients was pooled, digested, and fractionated by SCX chromatography prior to analysis by LC-MS/MS. Proteins identified were compared to published databases of proteins identified from CSF and plasma. AC fluid proteins not found in these two databases were experimentally searched for in lumbar CSF taken from neurologically-normal patients, by a targeted protein identification approach called MIDAS (Multiple Reaction Monitoring (MRM initiated detection and sequence analysis. Results We did not identify systematic trends or grouping of data in the AC protein comparison experiment, implying low variability between individual proteomic profiles of AC. In the AC proteome evaluation experiment, we identified 199 proteins. When compared to previously published lists of proteins identified from CSF and plasma, 15 of the AC proteins had not been reported in either of these datasets. By a targeted protein identification approach, we identified 11 of these 15 proteins in pooled CSF from neurologically-normal patients, demonstrating that

Control of Pan-tilt Mechanism Angle using Position Matrix Method

Directory of Open Access Journals (Sweden)

Hendri Maja Saputra

2013-12-01

Full Text Available Control of a Pan-Tilt Mechanism (PTM angle for the bomb disposal robot Morolipi-V2 using inertial sensor measurement unit, x-IMU, has been done. The PTM has to be able to be actively controlled both manually and automatically in order to correct the orientation of the moving Morolipi-V2 platform. The x-IMU detects the platform orientation and sends the result in order to automatically control the PTM. The orientation is calculated using the quaternion combined with Madwick and Mahony filter methods. The orientation data that consists of angles of roll (α, pitch (β, and yaw (γ from the x-IMU are then being sent to the camera for controlling the PTM motion (pan & tilt angles after calculating the reverse angle using position matrix method. Experiment results using Madwick and Mahony methods show that the x-IMU can be used to find the robot platform orientation. Acceleration data from accelerometer and flux from magnetometer produce noise with standard deviation of 0.015 g and 0.006 G, respectively. Maximum absolute errors caused by Madgwick and Mahony method with respect to Xaxis are 48.45º and 33.91º, respectively. The x-IMU implementation as inertia sensor to control the Pan-Tilt Mechanism shows a good result, which the probability of pan angle tends to be the same with yaw and tilt angle equal to the pitch angle, except a very small angle shift due to the influence of roll angle..

Comparison and evaluation of datasets for off-angle iris recognition

Science.gov (United States)

Kurtuncu, Osman M.; Cerme, Gamze N.; Karakaya, Mahmut

2016-05-01

In this paper, we investigated the publicly available iris recognition datasets and their data capture procedures in order to determine if they are suitable for the stand-off iris recognition research. Majority of the iris recognition datasets include only frontal iris images. Even if a few datasets include off-angle iris images, the frontal and off-angle iris images are not captured at the same time. The comparison of the frontal and off-angle iris images shows not only differences in the gaze angle but also change in pupil dilation and accommodation as well. In order to isolate the effect of the gaze angle from other challenging issues including dilation and accommodation, the frontal and off-angle iris images are supposed to be captured at the same time by using two different cameras. Therefore, we developed an iris image acquisition platform by using two cameras in this work where one camera captures frontal iris image and the other one captures iris images from off-angle. Based on the comparison of Hamming distance between frontal and off-angle iris images captured with the two-camera- setup and one-camera-setup, we observed that Hamming distance in two-camera-setup is less than one-camera-setup ranging from 0.05 to 0.001. These results show that in order to have accurate results in the off-angle iris recognition research, two-camera-setup is necessary in order to distinguish the challenging issues from each other.

Complete 360° circumferential SSOCT gonioscopy of the iridocorneal angle

Science.gov (United States)

McNabb, Ryan P.; Kuo, Anthony N.; Izatt, Joseph A.

2014-02-01

The ocular iridocorneal angle is generally an optically inaccessible area when viewed directly through the cornea due to the high angle of incidence required and the large index of refraction difference between air and cornea (nair = 1.000 and ncornea = 1.376) resulting in total internal reflection. Gonioscopy allows for viewing of the angle by removing the aircornea interface through the use of a special contact lens on the eye. Gonioscopy is used clinically to visualize the angle directly but only en face. Optical coherence tomography (OCT) has been used to image the angle and deeper structures via an external approach. Typically, this imaging technique is performed by utilizing a conventional anterior segment OCT scanning system. However, instead of imaging the apex of the cornea, either the scanner or the subject is tilted such that the corneoscleral limbus is orthogonal to the optical axis of the scanner requiring multiple volumes to obtain complete circumferential coverage of the ocular angle. We developed a novel gonioscopic OCT (GOCT) system that images the entire ocular angle within a single volume via an "internal" approach through the use of a custom radially symmetric gonioscopic contact lens. We present, to our knowledge, the first complete 360° circumferential volumes of the iridocorneal angle from a direct, internal approach.

Viewing angle switching of patterned vertical alignment liquid crystal display

International Nuclear Information System (INIS)

Lim, Young Jin; Jeong, Eun; Chin, Mi Hyung; Lee, Seung Hee; Ji, Seunghoon; Lee, Gi-Dong

2008-01-01

Viewing angle control of a patterned vertical alignment (PVA) liquid crystal display using only one panel is investigated. In conventional PVA modes, a vertically aligned liquid crystal (LC) director tilts down in four directions making 45 deg. with respect to crossed polarizers to exhibit a wide viewing angle. In the viewing angle control device, one pixel was divided into two sub-pixels such that the LC director in the main pixel is controlled to be tilted down in multiple directions making an angle with the polarizer, playing the role of main display with the wide viewing angle, while the LC director in the sub-pixel is controlled to be tilted down to the polarizer axis, playing the role of sub-pixel to the viewing angle control for the narrow viewing angle. Using sub-pixel control, light leakage or any type of information such as characters and image can be generated in oblique viewing directions without distorting the image quality in the normal direction, which will prevent others from peeping at the displayed image by overlapping the displayed image with the made image

Optimum Antenna Downtilt Angles for Macrocellular WCDMA Network

Directory of Open Access Journals (Sweden)

Niemelä Jarno

2005-01-01

Full Text Available The impact of antenna downtilt on the performance of cellular WCDMA network has been studied by using a radio network planning tool. An optimum downtilt angle has been evaluated for numerous practical macrocellular site and antenna configurations for electrical and mechanical antenna downtilt concepts. The aim of this massive simulation campaign was expected to provide an answer to two questions: firstly, how to select the downtilt angle of a macrocellular base station antenna? Secondly, what is the impact of antenna downtilt on system capacity and network coverage? Optimum downtilt angles were observed to vary between – depending on the network configuration. Moreover, the corresponding downlink capacity gains varied between – . Antenna vertical beamwidth affects clearly the required optimum downtilt angle the most. On the other hand, with wider antenna vertical beamwidth, the impact of downtilt on system performance is not such imposing. In addition, antenna height together with the size of the dominance area affect the required downtilt angle. Finally, the simulation results revealed how the importance of the antenna downtilt becomes more significant in dense networks, where the capacity requirements are typically also higher.

Rotating Shaft Tilt Angle Measurement Using an Inclinometer

Science.gov (United States)

Luo, Jun; Wang, Zhiqian; Shen, Chengwu; Wen, Zhuoman; Liu, Shaojin; Cai, Sheng; Li, Jianrong

2015-10-01

This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

Rotating Shaft Tilt Angle Measurement Using an Inclinometer

Directory of Open Access Journals (Sweden)

Luo Jun

2015-10-01

Full Text Available This paper describes a novel measurement method to accurately measure the rotating shaft tilt angle of rotating machine for alignment or compensation using a dual-axis inclinometer. A model of the rotating shaft tilt angle measurement is established using a dual-axis inclinometer based on the designed mechanical structure, and the calculation equation between the rotating shaft tilt angle and the inclinometer axes outputs is derived under the condition that the inclinometer axes are perpendicular to the rotating shaft. The reversal measurement method is applied to decrease the effect of inclinometer drifts caused by temperature, to eliminate inclinometer and rotating shaft mechanical error and inclinometer systematic error to attain high measurement accuracy. The uncertainty estimation shows that the accuracy of rotating shaft tilt angle measurement depends mainly on the inclinometer uncertainty and its uncertainty is almost the same as the inclinometer uncertainty in the simulation. The experimental results indicate that measurement time is 4 seconds; the range of rotating shaft tilt angle is 0.002° and its standard deviation is 0.0006° using NS-5/P2 inclinometer, whose precision and resolution are ±0.01° and 0.0005°, respectively.

Small Angle X-Ray Scattering Detector

Energy Technology Data Exchange (ETDEWEB)

Hessler, Jan P.

2004-06-15

A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.

Angle sensitive single photon avalanche diode

Energy Technology Data Exchange (ETDEWEB)

Lee, Changhyuk, E-mail: cl678@cornell.edu; Johnson, Ben, E-mail: bcj25@cornell.edu; Molnar, Alyosha, E-mail: am699@cornell.edu [Electrical and Computer Engineering, Cornell University, Ithaca, New York 14850 (United States)

2015-06-08

An ideal light sensor would provide exact information on intensity, timing, location, and angle of incoming photons. Single photon avalanche diodes (SPADs) provide such desired high (single photon) sensitivity with precise time information and can be implemented at a pixel-scale to form an array to extract spatial information. Furthermore, recent work has demonstrated photodiode-based structures (combined with micro-lenses or diffraction gratings) that are capable of encoding both spatial and angular information of incident light. In this letter, we describe the implementation of such a grating structure on SPADs to realize a pixel-scale angle-sensitive single photon avalanche diode (A-SPAD) built in a standard CMOS process. While the underlying SPAD structure provides high sensitivity, the time information of the two layers of diffraction gratings above offers angle-sensitivity. Such a unique combination of SPAD and diffraction gratings expands the sensing dimensions to pave a path towards lens-less 3-D imaging and light-field time-of-flight imaging.

Multi-Angle Snowflake Camera Instrument Handbook

Energy Technology Data Exchange (ETDEWEB)

Stuefer, Martin [Univ. of Alaska, Fairbanks, AK (United States); Bailey, J. [Univ. of Alaska, Fairbanks, AK (United States)

2016-07-01

The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASC cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.

A Study of Radiation Incidence Angle in Anteroposterior Cervical Vertebra Examination

International Nuclear Information System (INIS)

Jeung, Seung Woon; Lim, Cheong Hwan; Jung, Hong Ryang; Joo, Yeong Cheol; Park, Mi Ja; Han, Beon Hee

2012-01-01

In anteroposterior projection for cervical vertebra, it is general that the incidence angle of X-ray is 15 degrees to 20 degrees to head in order to prevent overlap of mandible and occipital bone and to observe array of cervical interbody and shapes of joints. However, the angle is appropriate for foreigners that was determined by foreign literature review long ago, and there have been few researches of incidence angle for Koreans' body type. The purpose of in this study are to identify the incidence angle appropriate for Koreans and to present methodology. In order to measure the incidence angle, 1,044 patients who visited S Hospital located in Seosan were selected and measured of average length of cervical vertebra, OID, axis angle, and FID. The incidence angle was calculated from the applied formula by measuring average values per age groups and sex (see Formula 1 and 2). The average length of cervical vertebra was 6cm: the length was increased from teenagers to twenties but was decreased since thirties. The difference between males and females was around 1cm (p<.01). The OID was almost the same regardless of age groups and sex. As for axis angle, the slope was increased in teenagers and twenties, but was decreased since thirties. The difference between males and females was around 2 degrees (p<.01). The FID measurements were almost the same regardless of age groups and sex, and when the incidence angle was measured from these values, the teenagers were 15.9 degrees, the twenties were 16.9 degrees, the thirties were 16.6 degrees, the forties were 16.2 degrees, the fifties were 15.9 degrees, and the sixties were 14.5 degrees, indicating that the angle was increased from teenagers to the twenties but decreased since the thirties. While the angles of males and females were measured to be the same in the teenagers, the angle was different between males and females by 2 degrees. When the incidence angle statistically analyzed with measurement of average length of

A Study of Radiation Incidence Angle in Anteroposterior Cervical Vertebra Examination

Energy Technology Data Exchange (ETDEWEB)

Jeung, Seung Woon; Lim, Cheong Hwan; Jung, Hong Ryang; Joo, Yeong Cheol; Park, Mi Ja [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of); Han, Beon Hee [Dept. of Radiological Science, Seonam University, Namwon (Korea, Republic of)

2012-06-15

In anteroposterior projection for cervical vertebra, it is general that the incidence angle of X-ray is 15 degrees to 20 degrees to head in order to prevent overlap of mandible and occipital bone and to observe array of cervical interbody and shapes of joints. However, the angle is appropriate for foreigners that was determined by foreign literature review long ago, and there have been few researches of incidence angle for Koreans' body type. The purpose of in this study are to identify the incidence angle appropriate for Koreans and to present methodology. In order to measure the incidence angle, 1,044 patients who visited S Hospital located in Seosan were selected and measured of average length of cervical vertebra, OID, axis angle, and FID. The incidence angle was calculated from the applied formula by measuring average values per age groups and sex (see Formula 1 and 2). The average length of cervical vertebra was 6cm: the length was increased from teenagers to twenties but was decreased since thirties. The difference between males and females was around 1cm (p<.01). The OID was almost the same regardless of age groups and sex. As for axis angle, the slope was increased in teenagers and twenties, but was decreased since thirties. The difference between males and females was around 2 degrees (p<.01). The FID measurements were almost the same regardless of age groups and sex, and when the incidence angle was measured from these values, the teenagers were 15.9 degrees, the twenties were 16.9 degrees, the thirties were 16.6 degrees, the forties were 16.2 degrees, the fifties were 15.9 degrees, and the sixties were 14.5 degrees, indicating that the angle was increased from teenagers to the twenties but decreased since the thirties. While the angles of males and females were measured to be the same in the teenagers, the angle was different between males and females by 2 degrees. When the incidence angle statistically analyzed with measurement of average length

New magic angle bumps and magic translation bumps

International Nuclear Information System (INIS)

Seeman, J.

1983-01-01

SLC beams of opposite charge can be transversely deflected in the same direction by RF fields in the accelerating cavities caused by girder tilts, coupler-asymmetries, or manufacturing errors. A symmetric deflection can be corrected by a magic angle bump if the deflection is located adjacent to one of the linac quadrupoles. However, if the deflection is located between quadrupoles, two magic angle bumps or a magic angle bump and a magic translation bump are needed for the correction. Several examples of translation bumps are included. A new magic angle bump is also presented which is longitudinally compressed and has significantly reduced particle excursions. Finally, if new correctors are added midway along the girders so that the number of correctors are doubled, then the longitudinal extent and the maximum particle excursion of these new magic bumps can be further reduced

Comparison of different passive knee extension torque-angle assessments

International Nuclear Information System (INIS)

Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro

2013-01-01

Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m −2 ; tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome. (paper)

Two angle dependent reactive infinite order sudden approximation

International Nuclear Information System (INIS)

Jellinek, J.; Kouri, D.J.

1984-01-01

The reactive infinite order sudden approximation is redeveloped in a manner in which the initial and final arrangement internal angles γ/sub lambda/ amd γ/sub ν/ enter as independent quantities. The analysis follows parallel to that due to Khare, Kouri, and Baer except that matching of the wave function from different arrangements is done in a manner such that no single γ/sub ν/ angle is associated with a particular γ/sub lambda/ angle. As a consequence, the matching surface parameter B/sub lambdanu/ does not occur

Broadband and wide-angle distributed Bragg reflectors based on amorphous germanium films by glancing angle deposition.

Science.gov (United States)

Leem, Jung Woo; Yu, Jae Su

2012-08-27

We fabricated the distributed Bragg reflectors (DBRs) with amorphous germanium (a-Ge) films consisted of the same materials at a center wavelength (λc) of 1.33 μm by the glancing angle deposition. Their optical reflectance properties were investigated in the infrared wavelength region of 1-1.9 μm at incident light angles (θ inc) of 8-70°, together with the theoretical analysis using a rigorous coupled-wave analysis simulation. The two alternating a-Ge films at the incident vapor flux angles of 0 and 75° were formed as the high and low refractive index materials, respectively. The a-Ge DBR with only 5 periods exhibited a normalized stop bandwidth (∆λ/λ c) of ~24.1%, maintaining high reflectance (R) values of > 99%. Even at a high θ inc of 70°, the ∆λ/λ c was ~21.9%, maintaining R values of > 85%. The a-Ge DBR with good uniformity was obtained over the area of a 2 inch Si wafer. The calculated reflectance results showed a similar tendency to the measured data.

Portable mini-chamber for temperature dependent studies using small angle and wide angle x-ray scattering

Science.gov (United States)

Dev, Arun Singh; Kumar, Dileep; Potdar, Satish; Pandit, Pallavi; Roth, Stephan V.; Gupta, Ajay

2018-04-01

The present work describes the design and performance of a vacuum compatible portable mini chamber for temperature dependent GISAXS and GIWAXS studies of thin films and multilayer structures. The water cooled body of the chamber allows sample annealing up to 900 K using ultra high vacuum compatible (UHV) pyrolytic boron nitride heater, thus making it possible to study the temperature dependent evolution of structure and morphology of two-dimensional nanostructured materials. Due to its light weight and small size, the chamber is portable and can be accommodated at synchrotron facilities worldwide. A systematic illustration of the versatility of the chamber has been demonstrated at beamline P03, PETRA-III, DESY, Hamburg, Germany. Temperature dependent grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) measurements were performed on oblique angle deposited Co/Ag multilayer structure, which jointly revealed that the surface diffusion in Co columns in Co/Ag multilayer enhances by increasing temperature from RT to ˜573 K. This results in a morphology change from columnar tilted structure to densely packed morphological isotropic multilayer.

[Comparison of anterior chamber angle examination by UBM, SL-OCT and gonioscopy].

Science.gov (United States)

Liu, Rui-jue; Wang, Men; Xia, Wen-tao; Yu, Xiao-ying; Chen, Jie-min; Zhou, Shu; Peng, Shu-ya; Liu, Dong-mei

2014-08-01

To compare the agreement of anterior chamber angle examination by ultrasound biomicroscope (UBM), slit lamp optical coherence tomography (SL-OCT), and gonioscopy in angle recession and angle closure. The anterior chamber angle was measured with UBM, SL-OCT and gonioscopy in turns for temporal, nasal, superior and inferior quadrant in the same dark room. The results were compared with the agreement of the three methods in angle recession and angle closure by χ2 test and Kappa test. There were no statistically significant differences of the three methods in testing angle closure and angle recession (P>0.05). The consistency of UBM and gonioscopy was better (Kappa value of 0.882) than that of SL-OCT and gonioscopy (Kappa value of 0.624). When testing angle recession, UBM is better than SL-OCT with gonioscopy as the standard. When testing angle closure, UBM, SL-OCT and gonioscopy have good agreement.

Contact angles on stretched solids

Science.gov (United States)

Mensink, Liz; Snoeijer, Jacco

2017-11-01

The surface energy of solid interfaces plays a central role in wetting, as they dictate the liquid contact angle. Yet, it has been challenging to measure the solid surface energies independently, without making use of Young's law. Here we present Molecular Dynamics (MD) simulations by which we measure the surface properties for all interfaces, including the solids. We observe change in contact angles upon stretching the solid substrates, showing that the surface energy is actually strain dependent. This is clear evidence of the so-called Shuttleworth effect, making it necessary to distinguish surface energy from surface tension. We discuss how this effect gives rise to a new class of elasto-capillary phenomena. ERC Consolidator Grant No. 616918.

Azimuth and angle gathers from wave equation imaging in VTI media

KAUST Repository

Alkhalifah, Tariq Ali

2009-01-01

Angles in common-image angle domain gathers refer to the scattering angle at the reflector and provide a natural access to analyzing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-space-frequency planes into angle-space planes simultaneously with applying the imaging condition in a transversely isotropic (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case anisotropic media differs from its isotropic counterpart, difference depending mainly on the strength of anisotropy.

Within tree variation of lignin, extractives, and microfibril angle coupled with the theoretical and near infrared modeling of microfibril angle

Science.gov (United States)

Brian K. Via; chi L. So; Leslie H. Groom; Todd F. Shupe; michael Stine; Jan. Wikaira

2007-01-01

A theoretical model was built predicting the relationship between microfibril angle and lignin content at the Angstrom (A) level. Both theoretical and statistical examination of experimental data supports a square root transformation of lignin to predict microfibril angle. The experimental material used came from 10 longleaf pine (Pinus palustris)...

Pre and post operative facial angles in patients submitted to rhinoplasty

Directory of Open Access Journals (Sweden)

Soccol, Andréa T

2008-09-01

Full Text Available Introduction: Parameters used in facial aesthetic surgeries are currently based on POWELL and HUMPHREYS (1. These authors have formulated suitable relations between the face and the nose, and defined the face angles. Objective: To compare pre and pos-operative nasolabial, nasofrontal, nasomental and nasofacial angles in patients submitted to rhinoseptoplasty. Method: Prospective analysis of 37 patients submitted to rhinoplasty, with an average of 30±11 years of age, being 13 (36% men and 24 (64% women. The nasolabial, nasofrontal, nasomental and nasofacial angles were measured and compared, before and after the surgery, in profile pictures. Results: An average increase of 8.6o in the nasolabial angle was observed, of 8.5o in the nasofrontal and reduction of 2.3o in the nasofacial angle, and all the measures presented a statistically significant difference between the pre and pos-operative period. The nasomental angle increased, on average, 1.6o, a difference without statistical importance. Conclusions: The nasolabial and nasofrontal angles increase significantly after rhinoseptoplasty, while the nasofacial angle diminishes. There was no significant alteration in the nasomental angle with the accomplishment of the surgery.

Neuromuscular adaptations associated with knee joint angle-specific force change.

Science.gov (United States)

Noorkõiv, Marika; Nosaka, Kazunori; Blazevich, Anthony J

2014-08-01

Neuromuscular adaptations to joint angle-specific force increases after isometric training have not yet been fully elucidated. This study examined angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL, joint angle 38.1° ± 3.7°) versus long (LL, 87.5° ± 6.0°) muscle lengths. Sixteen men trained three times a week for 6 wk either at SL (n = 8) or LL (n = 8). Voluntary maximal isometric knee extensor (MVC) force, doublet twitch force, EMG amplitudes (EMG/Mmax), and voluntary activation during MVC force (VA%) were measured at eight knee joint angles (30°-100°) at weeks 0, 3, and 6. Muscle volume and cross-sectional area (CSA) were measured from magnetic resonance imaging scans, and fascicle length (Lf) was assessed using ultrasonography before and after training. Clear joint angle specificity of force increase was seen in SL but not in LL. The 13.4% ± 9.7% (P = 0.01) force increase around the training angle in SL was related to changes in vastus lateralis and vastus medialis EMG/Mmax around the training angle (r = 0.84-0.88, P < 0.05), without changes in the doublet twitch force-angle relation or muscle size. In LL, muscle volume and CSA increased and the changes in CSA at specific muscle regions were correlated with changes in MVC force. A 5.4% ± 4.9% (P = 0.001) increase in Lf found in both groups was not associated with angle-specific force changes. There were no angle-specific changes in VA%. The EMG/Mmax, although not VA%, results suggest that neural adaptations underpinned training-related changes at short quadriceps lengths, but hypertrophic changes predominated after training at long lengths. The findings of this study should contribute to the development of more effective and evidence-based rehabilitation and strength training protocols.

Angle comparison using an autocollimator

Science.gov (United States)

Geckeler, Ralf D.; Just, Andreas; Vasilev, Valentin; Prieto, Emilio; Dvorácek, František; Zelenika, Slobodan; Przybylska, Joanna; Duta, Alexandru; Victorov, Ilya; Pisani, Marco; Saraiva, Fernanda; Salgado, Jose-Antonio; Gao, Sitian; Anusorn, Tonmueanwai; Leng Tan, Siew; Cox, Peter; Watanabe, Tsukasa; Lewis, Andrew; Chaudhary, K. P.; Thalmann, Ruedi; Banreti, Edit; Nurul, Alfiyati; Fira, Roman; Yandayan, Tanfer; Chekirda, Konstantin; Bergmans, Rob; Lassila, Antti

2018-01-01

Autocollimators are versatile optical devices for the contactless measurement of the tilt angles of reflecting surfaces. An international key comparison (KC) on autocollimator calibration, EURAMET.L-K3.2009, was initiated by the European Association of National Metrology Institutes (EURAMET) to provide information on the capabilities in this field. The Physikalisch-Technische Bundesanstalt (PTB) acted as the pilot laboratory, with a total of 25 international participants from EURAMET and from the Asia Pacific Metrology Programme (APMP) providing measurements. This KC was the first one to utilise a high-resolution electronic autocollimator as a standard. In contrast to KCs in angle metrology which usually involve the full plane angle, it focused on relatively small angular ranges (+/-10 arcsec and +/-1000 arcsec) and step sizes (10 arcsec and 0.1 arcsec, respectively). This document represents the approved final report on the results of the KC. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Ray-tracing studies for a whole-viewing-angle retroreflector

International Nuclear Information System (INIS)

Yang, B.; Friedsam, H.

2000-01-01

The APS Survey and Alignment team uses LEICA laser trackers for the majority of their alignment tasks. These instruments utilize several different retroreflectors for tracking the path of the laser interferometer. Currently in use are open-air corner cubes with an acceptance angle of ±20 degree, corner cube prisms with an acceptance angle of ±50degree, and a Cat's eye with an acceptance angle of ±60degree. Best measurement results can be achieved by using an open-air corner cube that eliminates the need for the laser beam to travel through a different medium before it returns to the instrument detector. However, the trade off is a small acceptance angle. In order to overcome the limitations of the small acceptance angles, Takatsuji et al. has proposed the creation of a full-viewing-angle retroreflector. Based on the notion that the radius R 1 of a common Cat's eye is proportional to R 2 , one can write: R 1 = (n minus 1)R 2 . In the case that n, the refractive index of glass, equals 2, the radii R 1 and R 2 are identical, and one can create a solid sphere Cat's eye. This design has the advantages that no adhesives are used to bond the two hemispheres together, misalignments between the hemispheres are not an issue, and most importantly, larger acceptance angles are possible. This paper shows the results of their ray tracing calculations characterizing the geometrical optics

Using Digital Technology to See Angles from Different Angles. Part 1: Corners

Science.gov (United States)

Host, Erin; Baynham, Emily; McMaster, Heather

2014-01-01

In Part 1 of their article, Erin Host, Emily Baynham and Heather McMaster use a combination of digital technology and concrete materials to explore the concept of "corners". They provide a practical, easy to follow sequence of activities that builds on students' understandings. [For "Using Digital Technology to See Angles from…

Associations between Narrow Angle and Adult Anthropometry: The Liwan Eye Study

Science.gov (United States)

Jiang, Yuzhen; He, Mingguang; Friedman, David S.; Khawaja, Anthony P.; Lee, Pak Sang; Nolan, Winifred P.; Yin, Qiuxia; Foster, Paul J.

2015-01-01

Purpose To assess the associations between narrow angle and adult anthropometry. Methods Chinese adults aged 50 years and older were recruited from a population-based survey in the Liwan District of Guangzhou, China. Narrow angle was defined as the posterior trabecular meshwork not visible under static gonioscopy in at least three quadrants (i.e. a circumference of at least 270°). Logistic regression models were used to examine the associations between narrow angle and anthropomorphic measures (height, weight and body mass index, BMI). Results Among the 912 participants, lower weight, shorter height, and lower BMI were significantly associated with narrower angle width (tests for trend: mean angle width in degrees vs weight p<0.001; vs height p<0.001; vs BMI p = 0.012). In univariate analyses, shorter height, lower weight and lower BMI were all significantly associated with greater odds of narrow angle. The crude association between height and narrow angle was largely attributable to a stronger association with age and sex. Lower BMI and weight remained significantly associated with narrow angle after adjustment for height, age, sex, axial ocular biometric measures and education. In analyses stratified by sex, the association between BMI and narrow angle was only observed in women. Conclusion Lower BMI and weight were associated with significantly greater odds of narrow angle after adjusting for age, education, axial ocular biometric measures and height. The odds of narrow angle increased 7% per 1 unit decrease in BMI. This association was most evident in women. PMID:24707840

Contact angle adjustment in equation-of-state-based pseudopotential model.

Science.gov (United States)

Hu, Anjie; Li, Longjian; Uddin, Rizwan; Liu, Dong

2016-05-01

The single component pseudopotential lattice Boltzmann model has been widely applied in multiphase simulation due to its simplicity and stability. In many studies, it has been claimed that this model can be stable for density ratios larger than 1000. However, the application of the model is still limited to small density ratios when the contact angle is considered. The reason is that the original contact angle adjustment method influences the stability of the model. Moreover, simulation results in the present work show that, by applying the original contact angle adjustment method, the density distribution near the wall is artificially changed, and the contact angle is dependent on the surface tension. Hence, it is very inconvenient to apply this method with a fixed contact angle, and the accuracy of the model cannot be guaranteed. To solve these problems, a contact angle adjustment method based on the geometry analysis is proposed and numerically compared with the original method. Simulation results show that, with our contact angle adjustment method, the stability of the model is highly improved when the density ratio is relatively large, and it is independent of the surface tension.

Angle gathers in wave-equation imaging for transversely isotropic media

KAUST Repository

Alkhalifah, Tariq Ali; Fomel, Sergey B.

2010-01-01

In recent years, wave-equation imaged data are often presented in common-image angle-domain gathers as a decomposition in the scattering angle at the reflector, which provide a natural access to analysing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-frequency planes into angle-frequency planes simultaneously with applying the imaging condition in a transversely isotropic with a vertical symmetry axis (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case of anisotropic media differs from its isotropic counterpart, with the difference depending mainly on the strength of anisotropy. Synthetic examples demonstrate the importance of including anisotropy in the angle gather generation as mapping of the energy is negatively altered otherwise. In the case of a titled axis of symmetry (TTI), the same VTI formulation is applicable but requires a rotation of the wavenumbers. © 2010 European Association of Geoscientists & Engineers.

Angle gathers in wave-equation imaging for transversely isotropic media

KAUST Repository

Alkhalifah, Tariq Ali

2010-11-12

In recent years, wave-equation imaged data are often presented in common-image angle-domain gathers as a decomposition in the scattering angle at the reflector, which provide a natural access to analysing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-frequency planes into angle-frequency planes simultaneously with applying the imaging condition in a transversely isotropic with a vertical symmetry axis (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case of anisotropic media differs from its isotropic counterpart, with the difference depending mainly on the strength of anisotropy. Synthetic examples demonstrate the importance of including anisotropy in the angle gather generation as mapping of the energy is negatively altered otherwise. In the case of a titled axis of symmetry (TTI), the same VTI formulation is applicable but requires a rotation of the wavenumbers. © 2010 European Association of Geoscientists & Engineers.

Axial vector mass spectrum and mixing angles

International Nuclear Information System (INIS)

Caffarelli, R.V.; Kang, K.

1976-01-01

Spectral sum rules of the axial-vector current and axial-vector current-pseudoscalar field are used to study the axial-vector mass spectrum and mixing angles, as well as the decay constants and mixing angles of the pseudoscalar mesons. In general, the result is quite persuasive for the existence of the Jsup(PC) = 1 ++ multiplet in which one has a canonical D-E mixing. (Auth.)

Lateral displacement in small angle multiple scattering

Energy Technology Data Exchange (ETDEWEB)

Bichsel, H.; Hanson, K.M.; Schillaci, K.M. (Los Alamos National Lab., NM (USA))

1982-07-01

Values have been calculated for the average lateral displacement in small angle multiple scattering of protons with energies of several hundred MeV. The calculations incorporate the Moliere distribution which does not make the gaussian approximations of the distribution in projected angle and lateral deflections. Compared to other published data, such approximations can lead to errors in the lateral displacement of up to 10% in water.

Escape angles in bulk chi((2)) soliton interactions

DEFF Research Database (Denmark)

Johansen, Steffen Kjær; Bang, Ole; Sørensen, Mads Peter

2002-01-01

We develop a theory for nonplanar interaction between two identical type I spatial solitons propagating at opposite, but arbitrary transverse angles in quadratic nonlinear (or so-called chi((2))) bulk, media. We predict quantitatively the outwards escape angle, below which the solitons turn around...

Automatic anterior chamber angle assessment for HD-OCT images.

Science.gov (United States)

Tian, Jing; Marziliano, Pina; Baskaran, Mani; Wong, Hong-Tym; Aung, Tin

2011-11-01

Angle-closure glaucoma is a major blinding eye disease and could be detected by measuring the anterior chamber angle in the human eyes. High-definition OCT (Cirrus HD-OCT) is an emerging noninvasive, high-speed, and high-resolution imaging modality for the anterior segment of the eye. Here, we propose a novel algorithm which automatically detects a new landmark, Schwalbe's line, and measures the anterior chamber angle in the HD-OCT images. The distortion caused by refraction is corrected by dewarping the HD-OCT images, and three biometric measurements are defined to quantitatively assess the anterior chamber angle. The proposed algorithm was tested on 40 HD-OCT images of the eye and provided accurate measurements in about 1 second.

Geometry and evolution of low-angle normal faults (LANF) within a Cenozoic high-angle rift system, Thailand: Implications for sedimentology and the mechanisms of LANF development

Science.gov (United States)

Morley, Chris K.

2009-10-01

At least eight examples of large (5-35 km heave), low-angle normal faults (LANFs, 20°-30° dip) occur in the Cenozoic rift basins of Thailand and laterally pass into high-angle extensional fault systems. Three large-displacement LANFs are found in late Oligocene-Miocene onshore rift basins (Suphan Buri, Phitsanulok, and Chiang Mai basins), they have (1) developed contemporaneous with, or after the onset of, high-angle extension, (2) acted as paths for magma and associated fluids, and (3) impacted sedimentation patterns. Displacement on low-angle faults appears to be episodic, marked by onset of lacustrine conditions followed by axial progradation of deltaic systems that infilled the lakes during periods of low or no displacement. The Chiang Mai LANF is a low-angle (15°-25°), high-displacement (15-35 km heave), ESE dipping LANF immediately east of the late early Miocene Doi Inthanon and Doi Suthep metamorphic core complexes. Early Cenozoic transpressional crustal thickening followed by the northward motion of India coupled with Burma relative to east Burma and Thailand (˜40-30 Ma) caused migmatization and gneiss dome uplift in the late Oligocene of the core complex region, followed by LANF activity. LANF displacement lasted 4-6 Ma during the early Miocene and possibly transported a late Oligocene-early Miocene high-angle rift system 35 km east. Other LANFs in Thailand have lower displacements and no associated metamorphic core complexes. The three LANFs were initiated as low-angle faults, not by isostatic rotation of high-angle faults. The low-angle dips appear to follow preexisting low-angle fabrics (thrusts, shear zones, and other low-angle ductile foliations) predominantly developed during Late Paleozoic and early Paleogene episodes of thrusting and folding.

Transperineal ultrasonography in stress urinary incontinence: The significance of urethral rotation angles.

Science.gov (United States)

Al-Saadi, Wasan Ismail

2016-03-01

To assess, using transperineal ultrasonography (TPUS), the numerical value of the rotation of the bladder neck [represented by the difference in the anterior (α angle) and posterior urethral angles (β angle)] at rest and straining, in continent women and women with stress urinary incontinence (SUI), to ascertain if there are significant differences in the angles of rotation (Rα and Rβ) between the groups. In all, 30 women with SUI (SUI group) and 30 continent women (control group) were included. TPUS was performed at rest and straining (Valsalva manoeuver), and the threshold value for the urethral angles (α and β angles) for each group were estimated. The degree of rotation for each angle was calculated and was considered as the angle of rotation. Both the α and β angles were significantly different between the groups at rest and straining, and there was a significant difference in the mean increment in the value of each angle. Higher values of increment (higher rotation angles) were reported in the SUI group for both the α and β angles compared with those of the control group [mean (SD) Rα SUI group 19.43 (12.76) vs controls 10.53 (2.98) °; Rβ SUI group 28.30 (12.96) vs controls 16.33 (10.8) °; P < 0.001]. Urethral rotation angles may assist in the assessment and diagnosis of patients with SUI, which may in turn reduce the need for more sophisticated urodynamic studies.

Optimal angle reduction - a behavioral approach to linear system appromixation

NARCIS (Netherlands)

Roorda, B.; Weiland, S.

2001-01-01

We investigate the problem of optimal state reduction under minimization of the angle between system behaviors. The angle is defined in a worst-case sense, as the largest angle that can occur between a system trajectory and its optimal approximation in the reduced-order model. This problem is

Design of Virtual Crank Angle Sensor based on Torque Estimation

OpenAIRE

Roswall, Tobias

2016-01-01

The topic of thesis is estimation of the crank angle based on pulse signals from an induction sensor placed on the flywheel. The engine management system performs many calculations in the crank angle domain which means that a good accuracy is needed for this measurement. To estimate the crank angle degree the torque balance on the crankshaft based on Newtons 2nd law is used. The resulting acceleration is integrated to give engine speed and crank angle. This approach is made for two crankshaft ...

Fat fraction bias correction using T1 estimates and flip angle mapping.

Science.gov (United States)

Yang, Issac Y; Cui, Yifan; Wiens, Curtis N; Wade, Trevor P; Friesen-Waldner, Lanette J; McKenzie, Charles A

2014-01-01

To develop a new method of reducing T1 bias in proton density fat fraction (PDFF) measured with iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL). PDFF maps reconstructed from high flip angle IDEAL measurements were simulated and acquired from phantoms and volunteer L4 vertebrae. T1 bias was corrected using a priori T1 values for water and fat, both with and without flip angle correction. Signal-to-noise ratio (SNR) maps were used to measure precision of the reconstructed PDFF maps. PDFF measurements acquired using small flip angles were then compared to both sets of corrected large flip angle measurements for accuracy and precision. Simulations show similar results in PDFF error between small flip angle measurements and corrected large flip angle measurements as long as T1 estimates were within one standard deviation from the true value. Compared to low flip angle measurements, phantom and in vivo measurements demonstrate better precision and accuracy in PDFF measurements if images were acquired at a high flip angle, with T1 bias corrected using T1 estimates and flip angle mapping. T1 bias correction of large flip angle acquisitions using estimated T1 values with flip angle mapping yields fat fraction measurements of similar accuracy and superior precision compared to low flip angle acquisitions. Copyright © 2013 Wiley Periodicals, Inc.

The Nasolabial Angle Among Patients with Total Cleft Lip and Palate.

Science.gov (United States)

Paradowska-Stolarz, Anna M; Kawala, Beata

2015-01-01

Nasolabial angle is the angle that is measured between points columella, subnasale and labiale superius. The reference values vary from 90 to 120 degrees (the mean value is 109.8 degrees). In some disorders, nasolabial angle might change. This influences the facial profile. One of such deformities are clefts. The nasolabial angle might be decreased in cleft patients due to deformation of the nose and upper lip that might be caused by the reconstructive surgical procedures performed. The aim of the study was to compare the nasolabial angle between the groups of patients with total clefts of the lip, alveolar bone and palate and healthy individuals. The cephalometric X-rays of 118 patients with clefts (73 boys and 45 girls) and 101 healthy individuals (32 boys and 69 girls) were taken into account to measure nasolabial angle and compared. In patients with cleft deformities, the nasolabial angle values were smaller than in healthy individuals. Among the patients with clefts, the ones with a bilateral type of deformity are characterized by the highest mean values of nasolabial angle. The angle is smaller in groups of girls when compared to boys. Nasolabial angle in patients with total clefts of lip, alveolar bone and palate is statistically smaller than in healthy individuals. This might be a result of either the deformation of the upper lip or (more probably) the nose. The orthodontic treatment should be individualized.

Angle-dependent bandgap engineering in gated graphene superlattices

Energy Technology Data Exchange (ETDEWEB)

García-Cervantes, H.; Sotolongo-Costa, O. [Centro de Investigación en Ciencias, IICBA, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209 Cuernavaca, Morelos, México (Mexico); Gaggero-Sager, L. M. [CIICAp, IICBA, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209 Cuernavaca, Morelos, México (Mexico); Naumis, G. G. [Instituto Física, Depto. de Física-Química, Universidad Nacional Autónoma de México (UNAM). Apdo. Postal 20-364, 01000, México D.F., México (Mexico); Rodríguez-Vargas, I., E-mail: isaac@fisica.uaz.edu.mx [Centro de Investigación en Ciencias, IICBA, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209 Cuernavaca, Morelos, México (Mexico); Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac., México (Mexico)

2016-03-15

Graphene Superlattices (GSs) have attracted a lot of attention due to its peculiar properties as well as its possible technological implications. Among these characteristics we can mention: the extra Dirac points in the dispersion relation and the highly anisotropic propagation of the charge carriers. However, despite the intense research that is carried out in GSs, so far there is no report about the angular dependence of the Transmission Gap (TG) in GSs. Here, we report the dependence of TG as a function of the angle of the incident Dirac electrons in a rather simple Electrostatic GS (EGS). Our results show that the angular dependence of the TG is intricate, since for moderated angles the dependence is parabolic, while for large angles an exponential dependence is registered. We also find that the TG can be modulated from meV to eV, by changing the structural parameters of the GS. These characteristics open the possibility for an angle-dependent bandgap engineering in graphene.

Angle-dependent bandgap engineering in gated graphene superlattices

International Nuclear Information System (INIS)

García-Cervantes, H.; Sotolongo-Costa, O.; Gaggero-Sager, L. M.; Naumis, G. G.; Rodríguez-Vargas, I.

2016-01-01

Graphene Superlattices (GSs) have attracted a lot of attention due to its peculiar properties as well as its possible technological implications. Among these characteristics we can mention: the extra Dirac points in the dispersion relation and the highly anisotropic propagation of the charge carriers. However, despite the intense research that is carried out in GSs, so far there is no report about the angular dependence of the Transmission Gap (TG) in GSs. Here, we report the dependence of TG as a function of the angle of the incident Dirac electrons in a rather simple Electrostatic GS (EGS). Our results show that the angular dependence of the TG is intricate, since for moderated angles the dependence is parabolic, while for large angles an exponential dependence is registered. We also find that the TG can be modulated from meV to eV, by changing the structural parameters of the GS. These characteristics open the possibility for an angle-dependent bandgap engineering in graphene.

Effect of impact angle on vaporization

Science.gov (United States)

Schultz, Peter H.

1996-09-01

Impacts into easily vaporized targets such as dry ice and carbonates generate a rapidly expanding vapor cloud. Laboratory experiments performed in a tenuous atmosphere allow deriving the internal energy of this cloud through well-established and tested theoretical descriptions. A second set of experiments under near-vacuum conditions provides a second measure of energy as the internal energy converts to kinetic energy of expansion. The resulting data allow deriving the vaporized mass as a function of impact angle and velocity. Although peak shock pressures decrease with decreasing impact angle (referenced to horizontal), the amount of impact-generated vapor is found to increase and is derived from the upper surface. Moreover, the temperature of the vapor cloud appears to decrease with decreasing angle. These unexpected results are proposed to reflect the increasing roles of shear heating and downrange hypervelocity ricochet impacts created during oblique impacts. The shallow provenance, low temperature, and trajectory of such vapor have implications for larger-scale events, including enhancement of atmospheric and biospheric stress by oblique terrestrial impacts and impact recycling of the early atmosphere of Mars.

Broken symmetries and the Cabibbo angle

International Nuclear Information System (INIS)

Lanik, J.

1975-04-01

Under the assumption that the SU(3) symmetry is broken down by the strong and electromagnetic interactions, a phenomenological theory of the Cabibbo angle theta is proposed. In this theory the angle theta is fixed, linking together the Cabibbo rotation in the SU(3) space and complete SU(3) breaking consisting of both the SU(3) Hamiltonian and vacuum non-invariances. Assuming that the value of theta is zero in the soft-pion limit and that, in this limit, the only forces responsible for the isotopic symmetry breaking are the usual photonic forces it is shown that the usual electromagnetic interactions can contribute for the value of theta only through the non-vanishing vacuum expectation value of a certain scalar field. Within the framework of the (3,average3)+(3,average3) chiral symmetry-breaking model and through the use of the experimental value of the ratio GAMMA (K→μν)/GAMMA(π→μν), the presented Cabibbo angle theory predicts the value sintheta=0.25 which is in good agreement with experiment. (Lanik, J.)

Internal Friction Angle of Metal Powders

Directory of Open Access Journals (Sweden)

Jiri Zegzulka

2018-04-01

Full Text Available Metal powders are components with multidisciplinary usage as their application is very broad. Their consistent characterization across all disciplines is important for ensuring repeatable and trouble-free processes. Ten metal powders were tested in the study. In all cases, the particle size distribution and morphology (scanning electron microscope—SEM photos were determined. The aim of this work was to inspect the flow behavior of metal powders through another measured characteristic, namely the angle of internal friction. The measured values of the effective internal friction angle in the range 28.6–32.9°, together with the spherical particle shape and the particle size distribution, revealed the likely dominant mode of the metal particle transfer mechanism for stainless steel 316L, zinc and aluminum powder. This third piston flow mechanism is described and illustrated in detail. The angle of internal friction is mentioned as another suitable parameter for the characterization of metal powders, not only for the relative simplicity of the determination but also for gaining insight into the method of the movement of individual particles during the flow.

Anomalous polymer collapse winding angle distributions

Science.gov (United States)

Narros, A.; Owczarek, A. L.; Prellberg, T.

2018-03-01

In two dimensions polymer collapse has been shown to be complex with multiple low temperature states and multi-critical points. Recently, strong numerical evidence has been provided for a long-standing prediction of universal scaling of winding angle distributions, where simulations of interacting self-avoiding walks show that the winding angle distribution for N-step walks is compatible with the theoretical prediction of a Gaussian with a variance growing asymptotically as Clog N . Here we extend this work by considering interacting self-avoiding trails which are believed to be a model representative of some of the more complex behaviour. We provide robust evidence that, while the high temperature swollen state of this model has a winding angle distribution that is also Gaussian, this breaks down at the polymer collapse point and at low temperatures. Moreover, we provide some evidence that the distributions are well modelled by stretched/compressed exponentials, in contradistinction to the behaviour found in interacting self-avoiding walks. Dedicated to Professor Stu Whittington on the occasion of his 75th birthday.

Studies in small angle scattering techniques

International Nuclear Information System (INIS)

Moellenbach, K.

1980-03-01

Small angle scattering of neutrons, X-rays and γ-rays are found among the spectroscopic methods developed in the recent years. Although these techniques differ from each other in many respects, e.g. radiation sources and technical equipment needed, their power to resolve physical phenomena and areas of application can be discussed in a general scheme. Selected examples are given illustrating the use of specific technical methods. Jahn-Teller driven structural phase transitions in Rare Earth zircons were studied with neutron scattering as well as small angle γ-ray diffraction. The study of neutron scattering from formations of magnetic domains in the Ising ferromagnet LiTbF 4 is a second example. Both these examples represent more than experimental test cases since the theoretical interpretations of the data obtained are discussed as well. As a last example the use of small angle scattering methods for the study of molecular biological samples is discussed. In particular the experimental procedures used in connection with scattering from aqueous solutions of proteins and protein complexes are given. (Auth.)

Numerical simulation of the effects of variation of angle of attack and sweep angle on vortex breakdown over delta wings

Science.gov (United States)

Ekaterinaris, J. A.; Schiff, Lewis B.

1990-01-01

In the present investigation of the vortical flowfield structure over delta wings at high angles of attack, three-dimensional Navier-Stokes numerical simulations were conducted to predict the complex leeward flowfield characteristics; these encompass leading-edge separation, secondary separation, and vortex breakdown. Attention is given to the effect on solution accuracy of circumferential grid-resolution variations in the vicinity of the wing leading edge, and well as to the effect of turbulence modeling on the solutions. When a critical angle-of-attack was reached, bubble-type vortex breakdown was found. With further angle-of-attack increase, a change from bubble-type to spiral-type vortex breakdown was predicted by the numerical solution.

Physiological response to angling of Africa's premier freshwater ...

African Journals Online (AJOL)

Blood plasma was analysed for glucose, cortisol and lactate concentrations to assess the effects of angling duration, fish size and fish condition. Larger fish were angled for a longer duration. Plasma glucose concentrations decreased with greater lactate concentrations, an indication of the aerobic and anaerobic work done ...

A study of images of Projective Angles of pulmonary veins

Energy Technology Data Exchange (ETDEWEB)

Wang Jue [Beijing Anzhen Hospital, Beijing (China); Zhaoqi, Zhang [Beijing Anzhen Hospital, Beijing (China)], E-mail: zhaoqi5000@vip.sohu.com; Yu Wei; Miao Cuilian; Yan Zixu; Zhao Yike [Beijing Anzhen Hospital, Beijing (China)

2009-09-15

Aims: In images of magnetic resonance and computed tomography (CT) there are visible angles between pulmonary veins and the coronary, transversal or sagittal section of body. In this study these angles are measured and defined as Projective Angles of pulmonary veins. Several possible influential factors and characters of distribution are studied and analyzed for a better understanding of this imaging anatomic character of pulmonary veins. And it could be the anatomic base of adjusting correctly the angle of the central X-ray of the angiography of pulmonary veins undergoing the catheter ablation of atrial fibrillation (AF). Method: Images of contrast enhanced magnetic resonance angiography (CEMRA) and contrast enhanced computer tomography (CECT) of the left atrium and pulmonary veins of 137 health objects and patients with atrial fibrillation (AF) are processed with the technique of post-processing, and Projective Angles to the coronary and transversal sections are measured and analyzed statistically. Result: Project Angles of pulmonary veins are one of real and steady imaging anatomic characteristics of pulmonary veins. The statistical distribution of variables is relatively concentrated, with a fairly good representation of average value. It is possible to improve the angle of the central X-ray according to the average value in the selective angiography of pulmonary veins undergoing the catheter ablation of AF.

Objectifying the adjacent and opposite angles: a cultural historical analysis

Science.gov (United States)

Daher, Wajeeh; Musallam, Nadera

2018-02-01

The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles' concepts. We videoed the learning of a group of three high-achieving students who used technology, specifically GeoGebra, to explore geometric relations related to the adjacent and opposite angles' concepts. To analyze students' objectification of these concepts, we used the categories of objectification of knowledge (attention and awareness) and the categories of generalization (factual, contextual and symbolic), developed by Radford. The research results indicate that teacher's and students' verbal and visual signs, together with the software dynamic tools, mediated the students' objectification of the adjacent and opposite angles' concepts. Specifically, eye and gestures perceiving were part of the semiosis cycles in which the participating students were engaged and which related to the mathematical signs that signified the adjacent and the opposite angles. Moreover, the teacher's suggestions/requests/questions included/suggested semiotic signs/tools, including verbal signs that helped the students pay attention, be aware of and objectify the adjacent and opposite angles' concepts.

Heterodyne Angle Deviation Interferometry in Vibration and Bubble Measurements

OpenAIRE

Ming-Hung Chiu; Jia-Ze Shen; Jian-Ming Huang

2016-01-01

We proposed heterodyne angle deviation interferometry (HADI) for angle deviation measurements. The phase shift of an angular sensor (which can be a metal film or a surface plasmon resonance (SPR) prism) is proportional to the deviation angle of the test beam. The method has been demonstrated in bubble and speaker’s vibration measurements in this paper. In the speaker’s vibration measurement, the voltage from the phase channel of a lock-in amplifier includes the vibration level and frequency. ...

Camber Angle Inspection for Vehicle Wheel Alignments.

Science.gov (United States)

Young, Jieh-Shian; Hsu, Hong-Yi; Chuang, Chih-Yuan

2017-02-03

This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU)-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x -axis or z -axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ± 0.015 ∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi.

Camber Angle Inspection for Vehicle Wheel Alignments

Directory of Open Access Journals (Sweden)

Jieh-Shian Young

2017-02-01

Full Text Available This paper introduces an alternative approach to the camber angle measurement for vehicle wheel alignment. Instead of current commercial approaches that apply computation vision techniques, this study aims at realizing a micro-control-unit (MCU-based camber inspection system with a 3-axis accelerometer. We analyze the precision of the inspection system for the axis misalignments of the accelerometer. The results show that the axes of the accelerometer can be aligned to the axes of the camber inspection system imperfectly. The calibrations that can amend these axis misalignments between the camber inspection system and the accelerometer are also originally proposed since misalignments will usually happen in fabrications of the inspection systems. During camber angle measurements, the x-axis or z-axis of the camber inspection system and the wheel need not be perfectly aligned in the proposed approach. We accomplished two typical authentic camber angle measurements. The results show that the proposed approach is applicable with a precision of ± 0.015 ∘ and therefore facilitates the camber measurement process without downgrading the precision by employing an appropriate 3-axis accelerometer. In addition, the measured results of camber angles can be transmitted via the medium such as RS232, Bluetooth, and Wi-Fi.

Lateral angle: a method for sexing using the petrous bone

DEFF Research Database (Denmark)

Norén, Anna; Lynnerup, Niels; Czarnetzki, Alfred

2005-01-01

skeletal remains or cremated bones, where the petrous bone may still be readily recognizable. The method was tested using a forensic sample of 113 petrous bones with known sex. Intra- and interobserver testing was also performed. We found a statistically significant difference in angle size between males...... and females (mean angle size of males, 39.3 degrees ; mean angle size of females, 48.2 degrees ; P tested the lateral angle method against an archaeological skeletal...... of the proximal part of the internal acoustic canal and determining the angle at which the canal opens up to the surface of the petrous bone. The method has the great advantage of utilizing one of the sturdiest bone elements of the human skeleton, and may thus be especially suited for analyses of very fragmented...

Determination of intrinsic spin Hall angle in Pt

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 (Singapore)

2014-10-13

The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.

Determination of intrinsic spin Hall angle in Pt

International Nuclear Information System (INIS)

Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo

2014-01-01

The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.

High Pressure Angle Gears: Comparison to Typical Gear Designs

Science.gov (United States)

Handschuh, Robert F.; Zabrajsek, Andrew J.

2010-01-01

A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).

An empirical investigation of German tourist anglers’ preferences for angling in Denmark

DEFF Research Database (Denmark)

Bonnichsen, Ole; Jensen, Carsten Lynge; Olsen, Søren Bøye

The quality of angling sites is important for attracting tourists who enjoy recreational angling. In this paper, we conduct an empirical analysis investigating which attributes of angling sites are particularly important for attracting tourist anglers from abroad. We conduct an online survey of 968...... at the site. To attract tourist anglers an angling site manager may use this information to target marketing efforts towards segments of tourist that prefer the type and quality of angling characteristics of the angling site in the managers possession. Additionally, he may seek to adjust and improve...

Precision measurements of the CKM angle gamma

CERN Multimedia

CERN. Geneva

2016-01-01

The level of CP-violation permitted within the Standard Model cannot account for the matter dominated universe in which we live. Within the Standard Model the CKM matrix, which describes the quark couplings, is expected to be unitary. By making precise measurements of the CKM matrix parameters new physics models can be constrained, or with sufficient precision the effects of physics beyond the standard model might become apparent. The CKM angle gamma is the least well known angle of the unitarity triangle. It is the only angle easily accessible at tree-level, and furthermore has almost no theoretical uncertainties. Therefore it provides an invaluable Standard Model benchmark against which other new physics sensitive tests of the CP-violation can be made. I will discuss recent measurements of gamma using the the Run 1 LHCb dataset, which improve our knowledge of this key parameter.

Bilateral Acute Angle-closure after Intraocular Surgery.

Science.gov (United States)

Hoskens, Kirsten; Pinto, Luis Abegão; Vandewalle, Evelien; Verdonk, Nancy; Stalmans, Ingeborg

2014-01-01

We report the case of a 75-year-old woman who developed an acute bilateral angle-closure associated with choroidal effusion a day after an uneventful cataract surgery. The same patient had undergone a similarly uneventful cataract surgery two weeks before, under the same protocol, with no postoperative complication in the other eye. Medical treatment, including the use of oral sulfamide-related drugs (acetazolamide), topical beta-blockers and steroids led to a gradual decrease in intraocular pressure (IOP) and choroidal effusion. Despite initial reports suggesting a link between sulfamide-exposure and these rare forms of angle-closure, our report would suggest a more complex pathophysiology behind this intriguing phenomenon. How to cite this article: Hoskens K, Pinto LA, Vandewalle E, Verdonk N, Stalmans I. Bilateral Acute Angle-closure after Intraocular Surgery. J Curr Glaucoma Pract 2014;8(3):113-114.

Drop rebound after impact: the role of the receding contact angle.

Science.gov (United States)

Antonini, C; Villa, F; Bernagozzi, I; Amirfazli, A; Marengo, M

2013-12-31

Data from the literature suggest that the rebound of a drop from a surface can be achieved when the wettability is low, i.e., when contact angles, measured at the triple line (solid-liquid-air), are high. However, no clear criterion exists to predict when a drop will rebound from a surface and which is the key wetting parameter to govern drop rebound (e.g., the "equilibrium" contact angle, θeq, the advancing and the receding contact angles, θA and θR, respectively, the contact angle hysteresis, Δθ, or any combination of these parameters). To clarify the conditions for drop rebound, we conducted experimental tests on different dry solid surfaces with variable wettability, from hydrophobic to superhydrophobic surfaces, with advancing contact angles 108° contact angles 89° contact angle is the key wetting parameter that influences drop rebound, along with surface hydrophobicity: for the investigated impact conditions (drop diameter 2.4 contact angles higher than 100°. Also, the drop rebound time decreased by increasing the receding contact angle. It was also shown that in general care must be taken when using statically defined wetting parameters (such as advancing and receding contact angles) to predict the dynamic behavior of a liquid on a solid surface because the dynamics of the phenomenon may affect surface wetting close to the impact point (e.g., as a result of the transition from the Cassie-Baxter to Wenzel state in the case of the so-called superhydrophobic surfaces) and thus affect the drop rebound.

Kinematics of reflections in subsurface offset and angle-domain image gathers

Science.gov (United States)

Dafni, Raanan; Symes, William W.

2018-05-01

Seismic migration in the angle-domain generates multiple images of the earth's interior in which reflection takes place at different scattering-angles. Mechanically, the angle-dependent reflection is restricted to happen instantaneously and at a fixed point in space: Incident wave hits a discontinuity in the subsurface media and instantly generates a scattered wave at the same common point of interaction. Alternatively, the angle-domain image may be associated with space-shift (regarded as subsurface offset) extended migration that artificially splits the reflection geometry. Meaning that, incident and scattered waves interact at some offset distance. The geometric differences between the two approaches amount to a contradictory angle-domain behaviour, and unlike kinematic description. We present a phase space depiction of migration methods extended by the peculiar subsurface offset split and stress its profound dissimilarity. In spite of being in radical contradiction with the general physics, the subsurface offset reveals a link to some valuable angle-domain quantities, via post-migration transformations. The angle quantities are indicated by the direction normal to the subsurface offset extended image. They specifically define the local dip and scattering angles if the velocity at the split reflection coordinates is the same for incident and scattered wave pairs. Otherwise, the reflector normal is not a bisector of the opening angle, but of the corresponding slowness vectors. This evidence, together with the distinguished geometry configuration, fundamentally differentiates the angle-domain decomposition based on the subsurface offset split from the conventional decomposition at a common reflection point. An asymptotic simulation of angle-domain moveout curves in layered media exposes the notion of split versus common reflection point geometry. Traveltime inversion methods that involve the subsurface offset extended migration must accommodate the split geometry

CONTACT ANGLE OF YUCCA MOUNTAIN WELDED TUFF WITH WATER AND BRINES

International Nuclear Information System (INIS)

H. Kalia

2006-01-01

A number of tests were performed to acquire contact angles between Yucca Mountain welded tuff from Topopah Springs Lower Lithophysal geologic unit and various brine solutions. The tests were performed on core disks received from Sample Management Facility (SMF), oven dried to a constant weight and the core disks vacuum saturated in: distilled water, J-13 water, calcium chloride brine and sodium chloride brine to constant weight. The contact angles were acquired from eight points on the surface of the core disks, four on rough surface, and four on polished surface. The contact angle was measured by placing a droplet of the test fluid, distilled water, J-13 water, calcium chloride brine and sodium chloride brine on the core disks. The objective of this test was to acquire contact angles as a potential input to estimating capillary forces in accumulated dust on the waste packages and drip shields slated for the proposed High-Level Radioactive Waste Repository at Yucca Mountain, Nevada. It was noted that once the droplet contacts the test surface, it continues to spread hence the contact angle continues to decrease with elapsed time. The maximum observed angle was at time 0 or when the drop contacted the rock surface. The measured contact angle, in all cases has significant scatter. In general, the time zero contact angles for core disks saturated in sodium chloride brine were smaller than those saturated in calcium chloride brine, distilled water, and J-13 water. The contact angles for samples saturated in distilled water, J-13 water and calcium chloride brine at time zero were similar. There was slight difference between the observed contact angles for smooth and rough surface of the test samples. The contact angles for smooth surfaces were smaller than for the rough surfaces

Low angle X-ray scattering

International Nuclear Information System (INIS)

Torrianni, I.L.

1983-01-01

The theoretical and experimental problems appearing in diffraction experiments at very low angles by several kinds of materials are discussed. The importance of synchrotron radiation in such problems is shown. (L.C.) [pt

Determination of the Basic Friction Angle of Rock Surfaces by Tilt Tests

Science.gov (United States)

Jang, Hyun-Sic; Zhang, Qing-Zhao; Kang, Seong-Seung; Jang, Bo-An

2018-04-01

Samples of Hwangdeung granite from Korea and Berea sandstone from USA, both containing sliding planes, were prepared by saw-cutting or polishing using either #100 or #600 grinding powders. Their basic friction angles were measured by direct shear testing, triaxial compression testing, and tilt testing. The direct shear tests and triaxial compression tests on the saw-cut, #100, and #600 surfaces indicated that the most reliable results were obtained from the #100 surface: basic friction angle of 29.4° for granite and 34.1° for sandstone. To examine the effect of surface conditions on the friction angle in tilt tests, the sliding angles were measured 50 times with two surface conditions (surfaces cleaned and not cleaned after each measurement). The initial sliding angles were high regardless of rock type and surface conditions and decreased exponentially as measurements continued. The characteristics of the sliding angles, differences between tilt tests, and dispersion between measurements in each test indicated that #100 surface produced the most reliable basic friction angle measurement. Without cleaning the surfaces, the average angles for granite (32 measurements) and sandstone (23 measurements) were similar to the basic friction angle. When 20-50 measurements without cleaning were averaged, the basic friction angle was within ± 2° for granite and ± 3° for sandstone. Sliding angles using five different tilting speeds were measured but the average was similar, indicating that tilting speed (between 0.2° and 1.6°/s) has little effect on the sliding angle. Sliding angles using four different sample sizes were measured with the best results obtained for samples larger than 8 × 8 cm.

Discriminating electromagnetic radiation based on angle of incidence

Science.gov (United States)

Hamam, Rafif E.; Bermel, Peter; Celanovic, Ivan; Soljacic, Marin; Yeng, Adrian Y. X.; Ghebrebrhan, Michael; Joannopoulos, John D.

2015-06-16

The present invention provides systems, articles, and methods for discriminating electromagnetic radiation based upon the angle of incidence of the electromagnetic radiation. In some cases, the materials and systems described herein can be capable of inhibiting reflection of electromagnetic radiation (e.g., the materials and systems can be capable of transmitting and/or absorbing electromagnetic radiation) within a given range of angles of incidence at a first incident surface, while substantially reflecting electromagnetic radiation outside the range of angles of incidence at a second incident surface (which can be the same as or different from the first incident surface). A photonic material comprising a plurality of periodically occurring separate domains can be used, in some cases, to selectively transmit and/or selectively absorb one portion of incoming electromagnetic radiation while reflecting another portion of incoming electromagnetic radiation, based upon the angle of incidence. In some embodiments, one domain of the photonic material can include an isotropic dielectric function, while another domain of the photonic material can include an anisotropic dielectric function. In some instances, one domain of the photonic material can include an isotropic magnetic permeability, while another domain of the photonic material can include an anisotropic magnetic permeability. In some embodiments, non-photonic materials (e.g., materials with relatively large scale features) can be used to selectively absorb incoming electromagnetic radiation based on angle of incidence.

Level Specific CE-Chirp® BAEP's: A new faster technique in neuromonitoring cochlear nerve during cerebello-pontine angle tumor surgery

Directory of Open Access Journals (Sweden)

Ettore Di Scipio, MD

2018-03-01

Conclusions: We herein confirm that LS CE-Chirp® BAEP's provide a fast feedback to surgeons regarding acoustic pathways function, helping them during skull base tumor removal in the attempt to hearing preservation when it is socially useful in the preoperative evaluation.

NORMAL AXIAL ANGLES OF THE KNEE JOINT IN ADULT ...

African Journals Online (AJOL)

hi-tech

2003-08-01

Aug 1, 2003 ... Conclusion: Our study has demonstrated comparative variations in means and ranges of normal axial angles .... population was significantly different from the mean ... case, however, the angle also exhibits racial variations.

Angle-domain inverse scattering migration/inversion in isotropic media

Science.gov (United States)

Li, Wuqun; Mao, Weijian; Li, Xuelei; Ouyang, Wei; Liang, Quan

2018-07-01

The classical seismic asymptotic inversion can be transformed into a problem of inversion of generalized Radon transform (GRT). In such methods, the combined parameters are linearly attached to the scattered wave-field by Born approximation and recovered by applying an inverse GRT operator to the scattered wave-field data. Typical GRT-style true-amplitude inversion procedure contains an amplitude compensation process after the weighted migration via dividing an illumination associated matrix whose elements are integrals of scattering angles. It is intuitional to some extent that performs the generalized linear inversion and the inversion of GRT together by this process for direct inversion. However, it is imprecise to carry out such operation when the illumination at the image point is limited, which easily leads to the inaccuracy and instability of the matrix. This paper formulates the GRT true-amplitude inversion framework in an angle-domain version, which naturally degrades the external integral term related to the illumination in the conventional case. We solve the linearized integral equation for combined parameters of different fixed scattering angle values. With this step, we obtain high-quality angle-domain common-image gathers (CIGs) in the migration loop which provide correct amplitude-versus-angle (AVA) behavior and reasonable illumination range for subsurface image points. Then we deal with the over-determined problem to solve each parameter in the combination by a standard optimization operation. The angle-domain GRT inversion method keeps away from calculating the inaccurate and unstable illumination matrix. Compared with the conventional method, the angle-domain method can obtain more accurate amplitude information and wider amplitude-preserved range. Several model tests demonstrate the effectiveness and practicability.

Association of iris crypts with acute primary angle closure.

Science.gov (United States)

Koh, Victor; Chua, Jacqueline; Shi, Yuan; Thakku, Sri Gowtham; Lee, Ryan; Nongpiur, Monisha E; Baskaran, Mani; Kumar, Rajesh S; Perera, Shamira; Aung, Tin; Cheng, Ching-Yu

2017-10-01

To determine the relationship between iris surface features and acute primary angle closure (APAC) in eyes with angle closure. Case-control study involving Asian patients diagnosed with previous APAC, primary angle closure suspect (PACS), primary angle closure (PAC) and primary angle closure glaucoma (PACG) at an eye centre in Singapore between August 2012 and January 2015. Participants underwent ophthalmic examination and digital slit-lamp iris photography. Iris surface features were graded based on crypts, furrows and colour. Fellow eyes of APAC were compared with PACS and PAC/PACG eyes with regard to their iris surface features. Occurrence of APAC. A total of 309 patients (71 APAC, 139 PACS, 47 PAC and 52 PACG) were included (mean age: 67.7±7.2 years and 36.6% male). Compared with PACS, higher crypt grade was significantly associated with lower odds of APAC (OR=0.58 for one grade higher in crypt grade; p=0.027, adjusted for age, gender, ethnicity and pupil diameter). The results remained similar when compared with PAC/PACG group (OR=0.58 for one grade higher in crypt grade; p=0.043). We did not observe any significant associations between iris furrows or colour with presence of APAC. Our study comprising Asian eyes with angle closure suggests that the presence of a higher crypt grading may be protective for APAC. As such, assessing iris surface architecture for crypts could be a new measure for risk stratification of developing APAC in eyes with angle closure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Objectifying the Adjacent and Opposite Angles: A Cultural Historical Analysis

Science.gov (United States)

Daher, Wajeeh; Musallam, Nadera

2018-01-01

The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles'…

open angle glaucoma (poag)?

African Journals Online (AJOL)

there is a build up of pressure due to poor outflow of aqueous humor. The outflow obstruction could occur at the trabecular meshwork of the anterior chamber angle or subsequently in the episcleral vein due to raised venous pressure. Such build up of pressure results in glaucoma . Elevated intraocular pressure remains the ...

INS as a probe of inter-monomer angles in polymers

CERN Document Server

Eijck, L V; Grozema, F C; Schepper, I M D; Kearley, G J

2002-01-01

The angle between monomers in conjugated polymers plays an important role in their conductivity. The vibrational spectrum is sensitive to this angle and can be used to probe the distribution of angles in poorly crystalline systems. We show that the INS spectrum is correctly calculated for bithiophene and shows the molecule to be planar in the solid - in agreement with crystallographic measurements. Poor agreement between observed and calculated spectra in the 700-cm sup - sup 1 region may be due to dynamic coupling, but this does not detract from the angle-sensitivity of the spectra. (orig.)

Increasing efficacy of graminicides with a forward angled spray

DEFF Research Database (Denmark)

Jensen, Peter Kryger

2012-01-01

Control of annual grass species with vertically oriented leaves in agricultural crops by application of foliar acting herbicides with conventional hydraulic sprayers can be increased using forward angled nozzles. Changing the spray angle from the normally predominantly vertical spray towards...... an angled spray increases the potential target size of vertically oriented targets. This theory was tested in field experiments from 2005 to 2009 investigating control of three different grass species and a dicotyledonous weed species at early growth stages using foliar acting herbicides. Lolium perenne...... efficacy on L. perenne at early growth stages using nozzles with different spray quality, at different driving speeds and in different wind conditions. Similarly graminicide efficacy was increased when nozzles were angled 60° forward controlling A. myosuroides. Experiments investigating control of the two...

Roentgenographic evaluation of the actual CCD and AT angle. Pt. 2

International Nuclear Information System (INIS)

Brueckl, R.; Grunert, S.; Rosemeyer, B.

1986-01-01

The method developed by Rippstein and Mueller allows a mathematically exact determination of the femoral neck-shaft angle (CCD) and the angle of torsion (AT); already at a deviation of 5-10 0 from the prescribed position of the patient considerable errors (up to more than 15 0 ) may occur. For this reason two alternative methods are cited and described in detail: a) the cinematographic determination of the CCD- and AT-angle according to Schwetlick, and b) the combination of the determination of the AT-angle in exterior rotation according to Rogers and an anteroposterior roentgenogram of the pelvis and hips in interior rotation of the size of the AT-angle. Both methods are also mathematically exact, however, in addition almost independent from minor deviations in the position of the patient. It is advisable to apply one of the cited methods in cases of high AT-angle values (>>30 0 ), in cases where the placing of the patient is difficult and where the determination of the angles would require a major therapeutic measurement. (orig.) [de

A stereological approach for measuring the groove angles of intergranular corrosion

International Nuclear Information System (INIS)

Gwinner, B.; Borgard, J.-M.; Dumonteil, E.; Zoia, A.

2017-01-01

Highlights: • The ICG morphology has been characterized in 3D by X-ray μ-tomography. • The measurement of the angles of the IGC groove on 2D cross sections induces a bias. • A methodology is proposed to estimate the true value of the IGC groove angles in 3D. - Abstract: Non-sensitized austenitic stainless steels can be prone to intergranular corrosion when they are in contact with an oxidizing medium like nitric acid. Intergranular corrosion is characterized by the formation of grooves along the grain boundaries. The angle of these grooves is a key parameter, which directly informs of the intergranular corrosion kinetics. Most of the time, the angles of the grooves are experimentally measured on 2-dimensional cross sections of the corroded samples. This study discusses the relationship between the groove angle measured on 2-dimensional sections and the true groove angle in 3-dimensional space. This approach could also be easily extended to the study of crack angle in the domains of corrosion-fatigue, stress corrosion cracking or mechanical fracture.