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Sample records for cervicothoracic junction case

  1. Migrated Disc at Cervicothoracic Junction Presenting as Acute Paraplegia

    PubMed Central

    Mahore, Amit; Agarwal, Monit; Tikeykar, Vishakha

    2015-01-01

    Herein, we report on an inferior migration of an intervertebral disc C6-7 to the cervicothoracic junction manifesting as acute paraplegia. The patient showed a remarkable recovery after the surgery. The diagnostic dilemma and management difficulties of such an entity are briefly discussed. PMID:26097662

  2. Migrated Disc at Cervicothoracic Junction Presenting as Acute Paraplegia.

    PubMed

    Mahore, Amit; Agarwal, Monit; Ramdasi, Raghvendra; Tikeykar, Vishakha

    2015-06-01

    Herein, we report on an inferior migration of an intervertebral disc C6-7 to the cervicothoracic junction manifesting as acute paraplegia. The patient showed a remarkable recovery after the surgery. The diagnostic dilemma and management difficulties of such an entity are briefly discussed. PMID:26097662

  3. Cervicothoracic junction thrust manipulation in the multimodal management of a patient with temporomandibular disorder.

    PubMed

    Jayaseelan, Dhinu J; Tow, Nancy S

    2016-05-01

    Temporomandibular disorder (TMD) is a common condition that can be difficult to manage in physical therapy. A number of interventions, such as manual therapy, therapeutic exercise, and patient education have typically been used in some combination. However, the evidence regarding thrust manipulation of not only the local but also adjacent segments is sparse. Specifically, the use of cervicothoracic (CT) junction thrust manipulation has not previously been described in the management of individuals with TMD. In this case report, CT junction thrust manipulation, in addition to locally directed manual therapy, exercise, and postural education, was associated with immediate improvements in neck and jaw symptoms and function in a complex patient with TMD. The patient was seen for seven visits over the course of 2 months and demonstrated clinically significant changes in the neck disability index (NDI), the numeric rating of pain scale (NPRS), and the global rating of change (GROC) scale. The purpose of this report is to describe the successful physical therapy management of a patient with TMD utilizing manual therapy, including CT junction thrust manipulation, education, and exercise. PMID:27559278

  4. Cervicothoracic Arachnoid Cyst Causing Cervical Myelopathy: A Case Report

    PubMed Central

    Kizilay, Zahir; Yilmaz, Ali; Ozkul, Ayca; Ismailoglu, Ozgur

    2015-01-01

    Several types of intraspinal cyst develop within the spinal canal from the craniovertebral junction to the sacrum. These lesions occur in both children and adults. Arachnoid cysts are one of them and are more frequent in the paediatric population, being a relatively uncommon lesion in adults. The arachnoid cyst may be located intradurally or extradurally. The intradural type may be congenital or from spinal trauma, infection or spondylosis. Although intradural arachnoid cysts are often asymptomatic, they may give early symptoms when they exist with synchronous pathologies constricting the spinal canal gradually as in cervical spondylosis. In this report, a 60-year-old man with an arachnoid cyst of the cervicothoracic spine is presented. His cyst remained undiagnosed because of the nonspecific nature of the symptoms. It was only when he developed right hemiparesis that a posterior fluid collection compressing the spinal cord was found in Magnetic resonance imaginig. An intradural extramedullary cyst was removed with successful surgery and cord compression and symptoms were reversed. We discuss radiological diagnosis and surgical treatment of an arachnoid cyst in this report. PMID:27275210

  5. Compressive Cervicothoracic Adhesive Arachnoiditis following Aneurysmal Subarachnoid Hemorrhage: A Case Report and Literature Review.

    PubMed

    Rahmathulla, Gazanfar; Kamian, Kambiz

    2014-08-01

    We present the case of a 55-year-old woman with diffuse adhesive arachnoiditis in the posterior fossa and cervicothoracic spine following posterior inferior cerebellar artery aneurysmal subarachnoid hemorrhage (SAH). She underwent aneurysm clipping with subsequent gradual neurologic decline associated with sensory disturbances, gait ataxia, and spastic paraparesis. Magnetic resonance imaging revealed diffuse adhesive arachnoiditis in the posterior fossa and cervicothoracic spine, syringobulbia, and multiple arachnoid cysts in the cervicothoracic spine along with syringohydromyelia. Early surgical intervention with microlysis of the adhesions and duraplasty at the clinically relevant levels resulted in clinical improvement. Although adhesive arachnoiditis, secondary arachnoid cysts, and cerebrospinal fluid flow abnormalities resulting in syrinx are rare following aneurysmal SAH, early recognition and appropriate intervention lead to good clinical outcomes. PMID:25083391

  6. Giant cell tumor of cervicothoracic region treated by triple corpectomy from posterior only approach: A case report with review of literature

    PubMed Central

    Mahajan, Rajat; Chhabra, Harvinder Singh; Tandon, Vikas; Venkatesh, Raghavendra

    2015-01-01

    Giant cell tumor (GCT) is a benign aggressive tumor, which affects axial as well as a peripheral skeleton. It affects epiphysis of long bones and can result in pathological fractures. GCT affects cervical spine rarely and has been known to affect almost all vertebra in the human body. It has a predilection for fixed spine, that is, sacrum though it can affect mobile spine as well. GCT of cervicothoracic region poses a challenge for the surgeon because of the difficulty in approaching this region anteriorly. This situation is further compounded when GCT involves multiple contiguous vertebral bodies in this region and has already spread beyond the confines of its capsule. We report a case of GCT involving three vertebral bodies C7, D1, and D2 at cervicothoracic region who presented to us and was treated with triple corpectomy from the posterior only approach. This is the first ever case report of triple corpectomy and anterior reconstruction by a posterior only approach for GCT at the cervicothoracic junction to the best of author's knowledge. PMID:26692702

  7. Large cervicothoracic myxoinflammatory fibroblastic sarcoma with brachial plexus invasion: A case report and literature review

    PubMed Central

    Jia, Xiaotian; Yang, Jianyun; Chen, Lin; Yu, Cong

    2016-01-01

    Myxoinflammatory fibroblastic sarcoma is a rare sarcoma that develops in patients of all ages, which usually presents as a slow-growing painless mass in the distal extremities. To date, myxoinflammatory fibroblastic sarcoma with invasion of the brachial plexus has rarely been reported in the literature. In this study, a case of large cervicothoracic sarcoma, which invaded the brachial plexus, is presented. The patient reported no sensory disturbance or dyskinesia. The tumor was completely resected without injury of the brachial plexus. The postoperative histological diagnosis was myxoinflammatory fibroblastic sarcoma. Follow-up examination performed 24 months after surgery revealed no tumor recurrence and no sensory disturbance or dyskinesia was reported. This study presents a rare case of large myxoinflammatory fibroblastic sarcoma with brachial plexus invasion that was successfully managed by surgery. PMID:27588121

  8. Traumatic spondyloptosis at the cervico-thoracic junction without neurological deficits

    PubMed Central

    Nguyen, Ha Son; Doan, Ninh; Lozen, Andrew; Gelsomino, Michael; Shabani, Saman; Kurpad, Shekar

    2016-01-01

    Background: There have been rare cases of traumatic cervical spondyloptosis without neurological compromise. We report another case and provide a review of the literature, with a focus on appropriate management. Case Description: A 60-year-old male rode his bicycle into a stationary semi-truck. He reported initial bilateral upper extremity paresthesias that resolved. Imaging demonstrated C7 on T1 spondyloptosis. Traction did not achieve reduction and a halo was applied. Subsequently, he underwent posterior decompression C6-T1, reduction via bilateral complete facetectomies at C7, and fixation from C4 to T2 fixation. Afterward, an anterior C7-T1 fixation occurred, where exposure was performed through a midline sternotomy. Postoperatively, he woke up with baseline motor and sensory examination in his extremities. He did exhibit voice hoarseness due to paralysis of the left vocal cords. He was discharged home 3 days after surgery. At 6 months follow-up, there was a progressive improvement of the left vocal cords to slight paresis; dynamic X-rays demonstrated no instability with good fusion progression. Conclusion: Traumatic cervical spondyloptosis without neurological compromise is a rare and challenging scenario. There is a concern for neurologic compromise with preoperative traction, but if specific posterior elements are fractured, the spinal canal may be wide enough where the concern for disc migration is minimal. For patients who have not been reduced preoperatively, a posterior approach with initial decompression to widen the canal, before reduction, appears safe. This scheme may avoid an initial anterior approach for decompression, necessitating a 3-stage procedure if circumferential stabilization is pursued. PMID:27274411

  9. Cervicothoracic cystic dysraphism.

    PubMed

    Valeur, Natalie S; Iyer, Ramesh S; Ishak, Gisele E

    2016-09-01

    Cystic dysraphism of the cervical and upper thoracic spine is very rare. It differs from the much more common lumbosacral dysraphism in appearance and structure, and usually portends a better prognosis due to lack of functional neurological tissue in the dysraphic sac and absent or less severe intracranial anomalies. There is ambiguity in the literature regarding terminology because of the paucity of cases. We present cases of the most common type of cervicothoracic cystic dysraphism and emphasize differences from lumbosacral myelomeningocele. Patient outcome depends on the presence of associated anomalies and whether complete surgical resection is performed. Imaging plays a critical role in surgical planning, screening the central nervous system for additional anomalies, and in the postoperative setting for evaluation of retethering. PMID:27147079

  10. Anaesthesia management of a case of Jervell and Lange-Nielsen syndrome for minimally invasive bilateral thoracoscopic cervicothoracic sympathectomy

    PubMed Central

    Roy, Preety Mittal; Khanna, Sangeeta; Mehta, Yatin; Khan, Ali Z

    2016-01-01

    Long QT syndrome (LQTS) is an arrhythmogenic cardiac disorder resulting from the malfunction of cardiac ion channels. Patient with LQTS may present with syncope, seizures or sudden cardiac death secondary to polymorphic ventricular tachycardia (VT) or torsades de pointes. Patient may be asymptomatic in the pre-operative period but may develop VT for the first time in operation theatre. We are reporting anaesthetic management of a child with LQTS planned for bilateral thoracoscopic cervicothoracic sympathectomy. PMID:27330206

  11. Anaesthesia management of a case of Jervell and Lange-Nielsen syndrome for minimally invasive bilateral thoracoscopic cervicothoracic sympathectomy.

    PubMed

    Roy, Preety Mittal; Khanna, Sangeeta; Mehta, Yatin; Khan, Ali Z

    2016-06-01

    Long QT syndrome (LQTS) is an arrhythmogenic cardiac disorder resulting from the malfunction of cardiac ion channels. Patient with LQTS may present with syncope, seizures or sudden cardiac death secondary to polymorphic ventricular tachycardia (VT) or torsades de pointes. Patient may be asymptomatic in the pre-operative period but may develop VT for the first time in operation theatre. We are reporting anaesthetic management of a child with LQTS planned for bilateral thoracoscopic cervicothoracic sympathectomy. PMID:27330206

  12. ECG-synchronized DSA exposure control: improved cervicothoracic image quality

    SciTech Connect

    Kelly, W.M.; Gould, R.; Norman, D.; Brant-Zawadzki, M.; Cox, L.

    1984-10-01

    An electrocardiogram (ECG)-synchronized x-ray exposure sequence was used to acquire digital subtraction angiographic (DSA) images during 13 arterial injection studies of the aortic arch or carotid bifurcations. These gated images were compared with matched ungated DSA images acquired using the same technical factors, contrast material volume, and patient positioning. Subjective assessments by five experienced observers of edge definition, vessel conspicuousness, and overall diagnostic quality showed overall preference for one of the two acquisition methods in 69% of cases studied. Of these, the ECG-synchronized exposure series were rated superior in 76%. These results, as well as the relatively simple and inexpensive modifications required, suggest that routine use of ECG exposure control can facilitate improved arterial DSA evaluations of suspected cervicothoracic vascular disease.

  13. Junction-to-Case Thermal Resistance of a Silicon Carbide Bipolar Junction Transistor Measured

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2006-01-01

    Junction temperature of a prototype SiC-based bipolar junction transistor (BJT) was estimated by using the base-emitter voltage (V(sub BE)) characteristic for thermometry. The V(sub BE) was measured as a function of the base current (I(sub B)) at selected temperatures (T), all at a fixed collector current (I(sub C)) and under very low duty cycle pulse conditions. Under such conditions, the average temperature of the chip was taken to be the same as that of the temperature-controlled case. At increased duty cycle such as to substantially heat the chip, but same I(sub C) pulse height, the chip temperature was identified by matching the V(sub BE) to the thermometry curves. From the measured average power, the chip-to-case thermal resistance could be estimated, giving a reasonable value. A tentative explanation for an observed bunching with increasing temperature of the calibration curves may relate to an increasing dopant atom ionization. A first-cut analysis, however, does not support this.

  14. Dorsolumbar junction spinal tuberculosis in an infant: case report.

    PubMed

    Tufan, Kadir; Dogulu, Fikret; Kardes, Ozgur; Oztanir, Namik; Baykaner, M Kemali

    2005-05-01

    The treatment of spinal tuberculosis is a challenging and controversial problem. The authors present the rare case of an 8-month-old infant with dorsolumbar junction tuberculosis. The child did not sit or stand and a hump was noted on his back. Radiological evaluations demonstrated destruction by a tuberculous abscess of the T-12 and L-1 vertebral bodies, extending into the psoas muscles and spinal canal. In addition to medical therapy, radical debridement and grafting were performed via an anterolateral approach. The follow-up period was 2 years. The difficulties in the management of spinal tuberculosis in infants are discussed. PMID:15926398

  15. A twelve-year survey of cervicothoracic vascular injuries.

    PubMed

    Bladergroen, M; Brockman, R; Luna, G; Kohler, T; Johansen, K

    1989-05-01

    This study of a large series of victims of trauma to the cervicothoracic great vessels confirms the lethal potential of these injuries: more than half of victims of such injuries died. The optimal management of patients potentially harboring such vascular damage appears to include skilled prehospital resuscitation and rapid transport to a trauma center, a high index of diagnostic suspicion, a low threshold for the performance of contrast arteriography, aggressive surveillance for associated neurologic and aerodigestive tract injuries, and timely technical repair, including liberal indications for sternotomy or thoracotomy to assure vascular control. PMID:2712204

  16. Huge cervico-thoracic thymic cyst.

    PubMed

    Sameh, Ibrahim Sersar; Ismaeil, Mohammed Fouad; Nasser, Mohammed Abdelhameed Fouda; Awadalla, Mohammed Mounir el-Saeid

    2003-09-01

    We present a case of a 6 year-old boy who presented with a huge mass in the right side of the neck and changes its size with respiration and with straining. Computed tomography of the chest and neck showed a huge mass that was thought to be cystic hygroma. It was excised by both median sternotomy and a right cervical incision. Pathology revealed a thymic cyst. PMID:17670062

  17. Utility of a 3-dimensional full-scale NaCl model for rib strut grafting for anterior fusion for cervicothoracic kyphosis

    PubMed Central

    Kobayashi, Kazuyoshi; Imagama, Shiro; Muramoto, Akio; Ito, Zenya; Ando, Kei; Yagi, Hideki; Hida, Tetsuro; Ito, Kenyu; Ishikawa, Yoshimoto; Tsushima, Mikito; Ishiguro, Naoki

    2015-01-01

    ABSTRACT In severe spinal deformity, pain and neurological disorder may be caused by spinal cord compression. Surgery for spinal reconstruction is desirable, but may be difficult in a case with severe deformity. Here, we show the utility of a 3D NaCl (salt) model in preoperative planning of anterior reconstruction using a rib strut in a 49-year-old male patient with cervicothoracic degenerative spondylosis. We performed surgery in two stages: a posterior approach with decompression and posterior instrumentation with a pedicle screw; followed by a second operation using an anterior approach, for which we created a 3D NaCl model including the cervicothoracic lesion, spinal deformity, and ribs for anterior reconstruction. The 3D NaCl model was easily scraped compared with a conventional plaster model and was useful for planning of resection and identification of a suitable rib for grafting in a preoperative simulation. Surgery was performed successfully with reference to the 3D NaCl model. We conclude that preoperative simulation with a 3D NaCl model contributes to performance of anterior reconstruction using a rib strut in a case of cervicothoracic deformity. PMID:26412901

  18. [Computed tomography imaging in ureteropelvic junction obstruction--case report].

    PubMed

    Pilch, Katarzyna; Jaźwiec, Przemysław; Truszkiewicz, Krystian; Gać, Paweł

    2016-01-01

    Ureteropelvic junction obstruction (UPJO) is defined as an impedance in the normal flow of urine from the renal pelvis into the proximal ureter. This leads to an increase urine pressure in the pelvicalyceal system and as a consequence cause hydronephrosis and damage of renal parenchyma. Presence of anomalous vessels crossing the ureter (crossing vessels) is one of the many reasons of UPJ obstruction. We report a case of 32-year-old female patient with chronic abdominal pain and recurrent episodes of pyelonephritis in the past. Contrast enhanced URO-CT was performed in order to determine the cause of complaints. This examination revealed right pelvicalyceal system dilatation and ipsilateral UPJ obstruction. After urological consultation patient was qualified for surgery, which aimed to decompress right pelvicalyceal system by changing anatomical conditions between the ureter and presumably crossing vessels. We demonstrate in the described case the value of contrast enhanced computed tomography URO-CT) in the diagnostic process of UPJ pathology. A multitude of information that we obtain from URO-CT examination allows the surgeon to reveal the cause of abnormal urine flow and choose the optimal operating method to minimize the risk of adverse events (such as intraoperative bleeding from mutilated crossing vessels). PMID:27120949

  19. MURCS (Müllerian duct aplasia–renal agenesis–cervicothoracic somite dysplasia): a rare cause of primary amenorrhoea

    PubMed Central

    Kumar, Sunil; Sharma, Shruti

    2016-01-01

    The agenesis of the Müllerian duct is the second most common cause of primary amenorrhoea after Turner syndrome. The abnormal development of Müllerian duct often associates with the urinary tract and skeletal abnormalities. MURCS (Müllerian duct aplasia–renal agenesis–cervicothoracic somite dysplasia) association is a unique and rare developmental disorder with four common features of uterine hypoplasia or aplasia, renal agenesis or ectopy, vertebral anomalies and short stature. We report a case of young female with primary amenorrhoea. She had well-developed secondary sexual characteristics along with multiple congenital developmental abnormalities such as the absence of uterus, ectopic kidney, cervical vertebral fusion, hemivertebrae, scoliosis, cervical rib, facial asymmetry and growth retardation. Our case highlights the rarity and clinical importance of this syndrome. For the evaluation of primary amenorrhoea in a female with well-developed secondary sexual characteristics, congenital anomalies should be ruled out before hormone and karyotype analyses. PMID:27099773

  20. MURCS (Müllerian duct aplasia-renal agenesis-cervicothoracic somite dysplasia): a rare cause of primary amenorrhoea.

    PubMed

    Kumar, Sunil; Sharma, Shruti

    2016-04-01

    The agenesis of the Müllerian duct is the second most common cause of primary amenorrhoea after Turner syndrome. The abnormal development of Müllerian duct often associates with the urinary tract and skeletal abnormalities. MURCS (Müllerian duct aplasia-renal agenesis-cervicothoracic somite dysplasia) association is a unique and rare developmental disorder with four common features of uterine hypoplasia or aplasia, renal agenesis or ectopy, vertebral anomalies and short stature. We report a case of young female with primary amenorrhoea. She had well-developed secondary sexual characteristics along with multiple congenital developmental abnormalities such as the absence of uterus, ectopic kidney, cervical vertebral fusion, hemivertebrae, scoliosis, cervical rib, facial asymmetry and growth retardation. Our case highlights the rarity and clinical importance of this syndrome. For the evaluation of primary amenorrhoea in a female with well-developed secondary sexual characteristics, congenital anomalies should be ruled out before hormone and karyotype analyses. PMID:27099773

  1. Distal ureteral atresia with ureteropelvic junction obstruction in a female child: a rare case

    PubMed Central

    Wu, Shuiqing; Xu, Ran; Zhu, Xuan; Zhao, Xiaokun

    2015-01-01

    This case report describes a distal ureteral atresia along with ureteropelvic junction obstruction which occurred in a 19-month-old female child. It is easily to be misdiagnosed as mere ureteropelvic junction obstruction and omitted the combined diagnosis of distal ureteral atresia. Dismembered pyeloplasty was done in local hospital after admission, however with the result of recurrent fever when clamp the left nephrostomy tube and Antegrade urography demonstrated distal ureteral atresia. After two months, boari flap reconstruction was performed for the patient in the Second Xiangya Hospital of Central South University, and the child had good rehabilitation in the end. To our knowledge, this is the first case report on distal ureteral atresia associated with ureteropelvic junction obstruction. PMID:25785157

  2. [A case of mixed adenoneuroendocrine carcinoma of the esophagogastric junction treated with neoadjuvant chemotherapy].

    PubMed

    Nakai, Makoto; Kawasaki, Hitoshi; Wajima, Naoki; Kimura, Akitoshi; Nakayama, Yoshihito; Muroya, Takahiro; Yonaiyama, Shinnosuke; Okano, Kensuke; Nagase, Hayato; Hakamada, Kenichi

    2013-11-01

    We present a case of a 63-year-old man who was admitted to another hospital because of abdominal distension and body weight loss. Gastric endoscopy revealed a type III tumor at the posterior wall of the upper gastric body. The tumor had invaded into the esophagogastric junction. On the basis of the pathology of the biopsy specimen, the tumor was diagnosed as neuroendocrine carcinoma of the esophagogastric junction. Computed tomography (CT) scans showed regional lymph node swelling. Cisplatin( CDDP) +irinotecan( CPT-11) therapy was selected and administered to the patient. After 2 courses, the patient received S-1+CDDP. He was considered to have stable disease. We performed partial resection of the lower esophagus, total gastrectomy, splenectomy, and cholecystectomy. On pathology, the tumor was immunohistochemically positive for chromogranin A, AE1/AE3, neural cell adhesion molecule (NCAM), neuron-specific enolase (NSE), and p53. The Ki-67 index was 80%. The tumor was diagnosed as a mixed adenoneuroendocrine carcinoma (MANEC) of the esophagogastric junction. The patient was treated with S-1 and CDDP. Neuroendocrine cell carcinoma of the esophagogastric junction is rare and usually has a very poor prognosis. We herein report a case of mixed adenoneuroendocrine carcinoma of the esophagogastric junction that was curatively resected and resulted in patient survival without recurrence. PMID:24394092

  3. [Pyelo-ureteral junction syndrome in horse-shoe kidney. Report of 13 cases].

    PubMed

    Sarf, I; Dahami, Z; Meziane, A; Dakir, M; Aboutaieb, R; el Moussaoui, A; Meziane, F

    2003-10-01

    The pelviureteral junction upon a horse shoe kidney remains a frequent congenital malformation. The authors report 13 cases collected during a period of 16 years and treated surgically. The review of literature permits to discuss the different therapeutic means. PMID:14606309

  4. Congenital anterior urethrocutaneous fistula at the penoscrotal junction with proximal penile megalourethra: A case report

    PubMed Central

    Cheng, Shih-Yao; Chen, Shyh-Jye; Lai, Hong-Shiee

    2016-01-01

    Congenital anterior urethrocutaneous fistula and megalourethra are both rare anomalies. These anomalies are commonly associated with other anorectal or genitourinary anomalies and evaluated with voiding cystourethrography. We examined a 34-month-old boy who presented with a fistula at the penoscrotal junction. A voiding cystourethrogram showed a jet of urine coming through the fistula and proximal saccular dilatation of the penile urethra. We present the imaging findings of the first case of an association between a congenital anterior urethrocutaneous fistula at the penoscrotal junction and a proximal penile megalourethra. We also discuss the etiology, management, and differential diagnosis of this entity, and review the literature. PMID:27200160

  5. Basilar artery aneurysm at a persistent trigeminal artery junction. A case report and literature review.

    PubMed

    Aguiar, G B; Conti, M L M; Veiga, J C E; Jory, M; Souza, R B

    2011-09-01

    The trigeminal artery is an anastomosis between the embryonic precursors of the vertebrobasilar and carotid systems, and may persist into adult life. The association of the persistent primitive trigeminal artery (PTA) with cerebral aneurysm is well documented in the literature and, in general, aneurysms are located in the anterior circulation. We describe a patient who presented with a panencephalic Fisher III subarachnoid hemorrhage due to rupture of an intracranial aneurysm. Digital arteriography showed a saccular aneurysm in the middle third of the basilar artery, adjacent to the junction with a persistent trigeminal artery. She was submitted to endovascular treatment with embolization of the basilar artery aneurysm with coils. Aneurysms at the PTA junction with the basilar artery are rare. This paper describes a case of PTA associated with an aneurysm in the basilar artery at PTA junction and briefly reviews the literature. PMID:22005697

  6. Clinical Features of Herniated Disc at Cervicothoracic Junction Level Treated by Anterior Approach

    PubMed Central

    Lee, Jun Gue; Kim, Hyeun Sung; Ju, Chang Il

    2016-01-01

    Objective The anterior approach for C7-T1 disc herniation may be challenging because of obstruction by the manubrium and the narrow operative field. This study aimed to investigate the clinical and neurological outcomes of anterior approach for C7-T1 disc herniation. Methods We retrospectively evaluated 13 patients who underwent the anterior approach for C7-T1 disc herniation by a single surgeon within a period of 11 years (2003-2014). The minimum follow-up duration was 6 months. We describe the clinical presentation, radiographic findings, neurological outcome, and related complications. Results Of 372 patients with single-level anterior discectomy and fusion or artificial disc replacement for cervical disc herniation, 13 (3.5%) had C7-T1 disc herniation. The main clinical presentation was unilateral motor weakness in intrinsic hand muscles (11 patients), along with numbness, pain, and tingling sensation that radiate down the arm to the little finger. Most of the patients improved after surgery via the anterior approach. Ten patients underwent successful anterior discectomy and fusion by the standard supramanubrial Smith-Robinson approach, but 2 needed additional manubriotomy and sternotomy. In 1 patient, we performed surgery at a wrong level because the correct level was difficult to identify intraoperatively. Two patients had transient vocal dysfunction, but none had major complications related to injuries of the great vessels such as the thoracic duct or esophagus. Conclusion For patients who require direct anterior decompression for C7-T1 disc herniation, the anterior approach is relatively feasible. However, care should be taken to overcome physical constraints by the manubrium and slope. PMID:27437013

  7. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    NASA Astrophysics Data System (ADS)

    Buzhynskyy, Nikolay; Sens, Pierre; Behar-Cohen, Francine; Scheuring, Simon

    2011-08-01

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  8. Upper cervicothoracic sympathetic block increases blood supply of unipedicled TRAM flap.

    PubMed

    Tsoutsos, Dimosthenis; Kakagia, Despoina; Gravvanis, Andreas; Iconomou, Thomais; Tsagkarakis, Myron; Zogogiannis, Ioannis; Dimitriou, Vassilios

    2008-09-01

    A prospective clinical study was conducted to evaluate the impact of upper cervicothoracic sympathetic block (CTGB) on blood supply of the unipedicled transverse rectus abdominis musculocutaneous (TRAM) flap. The use of the technique is first reported herein, as a manipulation improving arterial blood flow within the flap in high-risk patients, thus reducing postoperative morbidity. From March 2003 to September 2006, 28 heavy smokers, who underwent delayed breast reconstruction with unipedicled TRAM flap, were included in the study. Intraoperative upper cervicothoracic block (ganglia C5,6,7 and T1,2) was performed in 16 patients (group A), while 12 patients, who did not consent to have the blockade (group B), were the control. Clinical evaluation and thermographic monitoring of skin temperature, using the Thermacam A40 (FLIR systems, Wilsonville, OR), was used in all patients and determined the blood flow within the flap. All patients were monitored for early and late complications. In all group A patients, CTGB resulted in TRAM flap temperature increase within 9.5 to 16 min. Flap temperature elevation was found to be significantly higher (P < 0.001) and hospital stay was significantly shorter (P = 0.004) in group A patients. No CTGB or TRAM flap complications were recorded in group A patients. However, in group B, major fat necrosis occurred in 2 patients and partial (1/3) flap necrosis in 1 patient. Upper cervicothoracic sympathetic block is a reliable, safe, and useful technique for increasing blood flow within TRAM flaps in high-risk patients, like heavy smokers, and it minimizes postoperative morbidity. PMID:18724121

  9. Vertebral artery anomalies at the craniovertebral junction: a case report and review of the literature.

    PubMed

    Abtahi, Amir M; Brodke, Darrel S; Lawrence, Brandon D

    2014-10-01

    Study Design Case report. Objective The objective of this study was to report a case of an unstable C1 burst fracture in the setting of a vertebral artery anomaly at the craniovertebral junction. Methods A 55-year-old man was admitted to the hospital with severe neck pain after falling approximately 15 feet and landing on his head. Computed tomography scan of the cervical spine revealed an unstable fracture of the C1 ring with magnetic resonance imaging evidence of a transverse ligament rupture as well as a congenital synchondrosis of the posterior arch of C1. He was neurologically intact. CT angiography (CTA) of the neck revealed an anomalous course of the right vertebral artery at the C1-C2 level. Results Surgical intervention consisted of occiput-C3 fusion, thus avoiding the placement of C1 lateral mass screws and risking vertebral artery injury. Conclusion We present a case of an unstable C1 burst fracture with an anomalous course of the right vertebral artery demonstrated by CTA. The presence of vertebral artery anomalies at the craniovertebral junction may prevent safe placement of C1 lateral mass screws and therefore influence the treatment options for upper cervical spine pathologies. To minimize the risk of vertebral artery injury, we elected to perform an occiput to C3 fusion. Thorough assessment of the vascular anatomy is recommended before operative intervention in the upper cervical spine to minimize the risk of complications. PMID:25364325

  10. Cervicothoracic Subcutaneous Emphysema and Pneumomediastinum After Third Molar Extraction.

    PubMed

    Picard, Maxime; Pham Dang, Nathalie; Mondie, Jean Michel; Barthelemy, Isabelle

    2015-12-01

    Third molar extraction is one of the most common interventions in dental and maxillofacial surgery. Complications are frequent and well documented, with swelling, pain, bleeding, infection, and lingual or alveolar nerve injury being the most common. This report describes a case of subcutaneous extensive emphysema and pneumomediastinum that occurred 4 days after extraction of an impacted right mandibular third molar. The management and etiology of this case and those reported in the literature are discussed. PMID:26341684

  11. Craniovertebral junction instability as an extension of cocaine-induced midline destructive lesions: case report.

    PubMed

    Brembilla, Carlo; Lanterna, Luigi Andrea; Risso, Andrea; Bombana, Enrico; Gritti, Paolo; Trezzi, Rosangela; Bonaldi, Giuseppe; Biroli, Francesco

    2015-08-01

    With the increasingly widespread illicit use of cocaine, a broad spectrum of clinical pathologies related to this form of drug abuse is emerging. The most frequently used method of administration of powdered cocaine is intranasal inhalation, or "snorting." Consequently, adverse effects of cocaine on the nasal tract are common. Habitual nasal insufflations of cocaine can cause mucosal lesions. If cocaine use becomes chronic and compulsive, progressive damage of the mucosa and perichondrium leads to ischemic necrosis of the septal cartilage and perforation of the nasal septum. Occasionally, cocaine-induced lesions cause extensive destruction of the osteocartilaginous structures of the nose, sinuses, and palate and can mimic other diseases such as tumors, infections, and immunological diseases. In the literature currently available, involvement of the craniovertebral junction in the cocaine-induced midline destructive lesions (CIMDLs) has never been reported. The present case concerns a 44-year-old man who presented with long-standing symptoms including nasal obstruction, epistaxis, dysphagia, nasal reflux, and severe neck pain. A diagnosis of CIMDL was made in light of the patient's history and the findings on physical and endoscopic examinations, imaging studies, and laboratory testing. Involvement of the craniovertebral junction in the destructive process was evident. For neurosurgical treatment, the authors considered the high grade of atlantoaxial instability, the poorly understood cocaine-induced lesions of the spine and their potential evolution overtime, as well as cocaine abusers' poor compliance. The patient underwent posterior craniovertebral fixation. Understanding, classifying, and treating cocaine-induced lesions involving the craniovertebral junction are a challenge. PMID:25955800

  12. Spontaneous epidural hematoma due to cervico-thoracic angiolipoma.

    PubMed

    Eap, C; Bannwarth, M; Jazeron, J-F; Kleber, J-C; Theret, É; Duntze, J; Litre, C-F

    2015-12-01

    Epidural angiolipomas are uncommon benign tumors of the spine. Their clinical presentation is usually a progressive spinal cord compression. We report the case of a 22-year-old patient who presented with an acute paraparesis and a spontaneous epidural hematoma, which revealed a epidural angiolipoma which extended from C7 to T3. The patient underwent a C7-T3 laminectomy, in emergency, with evacuation of the hematoma and extradural complete resection of a fibrous epidural tumor bleeding. The postoperative course was favorable with regression of neurological symptoms. Epidural angiolipomas can be revealed by spontaneous intratumoral hemorrhage without traumatism. The standard treatment is total removal by surgery. PMID:26597606

  13. True Cervicothoracic Meningocele: A Rare and Benign Condition

    PubMed Central

    Pessoa, Bruno L.; Lima, Yara

    2015-01-01

    Cervical meningoceles are rare spinal dysraphism, accounting for approximately 7% of all cystic spinal dysraphism. In spite of the rarity, the clinical course is most of the times benign. The surgical treatment includes resection of the lesion and untethering, when presented. We present a 14-day-old female child with true meningoceles who underwent to surgical excision and dura-mater repair. Retrospect analysis of the literature concerning true cervical meningocele is performed. By reporting this illustrative case, we focus on its classification and its differentiation from other types of cervical spinal dysraphism, such as myelocystocele and myelomeningocele. Although its course is benign, it is mandatory a continuum follow up with periodic magnetic resonance imaging of spinal cord, since late neurological deterioration has been described. PMID:26788266

  14. Singular layers for transmission problems in thin shallow shell theory: Elastic junction case

    NASA Astrophysics Data System (ADS)

    Merabet, Ismail; Chacha, D. A.; Nicaise, Serge

    2010-05-01

    In this Note we study two-dimensional transmission problems for the linear Koiter's model of an elastic multi-structure composed of two thin shallow shells with the same thickness ɛ≪1, in the elastic junction case. We suppose that the loading is singular, that the elastic coefficients are of different order on each part ( O(ɛ) and O(1) respectively) and that the elastic stiffness coefficient of the hinge is k=O(ɛ). The formal limit problem fails to give a solution satisfying all boundary and transmission conditions; it gives only the outer solution. We derive the inner limit problem which allows us to describe the transmission layer.

  15. [Surgical treatment for ureteropelvic junction syndrome in infants and children (report of 73 cases)].

    PubMed

    Michel, A; Monod, P; Descotes, J L; Rambeaud, J J; Bourdat, G; Faure, G

    1991-12-01

    between 1982 and 1990, 73 children were operated for pyeloureteric junction syndrome (76 pyeloplasties). The authors distinguish between a group of 45 infants operated before the age of 2 years and a group of 35 children operated after the age of 2 years. 40% of these cases had been detected antenatally, which modified the management and treatment of these infants, operated at about the age of 6 months (mean: 6.6 months). Treatment was conservative (one nephrectomy out of the 41 infants operated: 2.4%). Pyeloplasty was performed according to the Anderson-Hynes-Küss resection-anastomosis technique under an operating magnifying glass. Early surgery offers the best chance of recovery. Urinary tract drainage was not systematic in these infants (50% of cases) and did not affect the long term results. Early complications and surgical revisions (3.9%) were not more frequent in the infants operated earlier. The definitive results were good in 88.5% of cases, while 7.2% of cases required further surveillance. Renal parenchymal lesions (4.3%) were related more to pyelonephritis than to failure of surgery. Overall, a conservative surgical approach is recommended, except in minor syndromes which require rigorous surveillance. PMID:1844746

  16. Solitons in Josephson junctions

    NASA Astrophysics Data System (ADS)

    Ustinov, A. V.

    1998-11-01

    Magnetic flux quanta in Josephson junctions, often called fluxons, in many cases behave as solitons. A review of recent experiments and modelling of fluxon dynamics in Josephson circuits is presented. Classic quasi-one-dimensional junctions, stacked junctions (Josephson superlattices), and discrete Josephson transmission lines (JTLs) are discussed. Applications of fluxon devices as high-frequency oscillators and digital circuits are also addressed.

  17. Traumatic Tear of the Latissimus Dorsi Myotendinous Junction: Case Report of a CrossFit-Related Injury.

    PubMed

    Friedman, Michael V; Stensby, J Derek; Hillen, Travis J; Demertzis, Jennifer L; Keener, Jay D

    2015-01-01

    A case of a latissimus dorsi myotendinous junction strain in an avid CrossFit athlete is presented. The patient developed acute onset right axillary burning and swelling and subsequent palpable pop with weakness while performing a "muscle up." Magnetic resonance imaging examination demonstrated a high-grade tear of the right latissimus dorsi myotendinous junction approximately 9 cm proximal to its intact humeral insertion. There were no other injuries to the adjacent shoulder girdle structures. Isolated strain of the latissimus dorsi myotendinous junction is a very rare injury with a scarcity of information available regarding its imaging appearance and preferred treatment. This patient was treated conservatively and was able to resume active CrossFit training within 3 months. At 6 months postinjury, he had only a mild residual functional deficit compared with his preinjury level. PMID:26502450

  18. Tumor Biology: Is It Time to Redefine Unresectability? An Extraordinary Case of Gastroesophageal Junctional Adenocarcinoma

    PubMed Central

    Giakoustidis, Alex; Winslet, Mark; Mudan, Satvinder

    2015-01-01

    Background: Disease assessment based on measurements of size and anatomic involvement have historically been central to surgical strategy. We propose this to be an outdated concept, which should be replaced by a deeper understanding of tumor biology and careful treatment planning. Report of case: A 34-year-old male was diagnosed with a Siewert Type 3 locally advanced cancer of the gastroesophageal junction, involving the coeliac axis and the superior mesenteric artery (SMA). He was treated with neoadjuvant chemotherapy, followed by chemoradiation, and then proceeded to surgery, at which time the tumor was judged unresectable. After extensive planning, a further surgery was attempted - an extended gastrectomy with distal esophagectomy, left hepatectomy, and splenectomy were performed. Additionally, the coeliac axis and the SMA were excised, followed by reconstruction of the hepatic artery and the SMA with grafts. Adjuvant chemotherapy was administered, and the patient is recurrence-free after five years follow-up. Conclusion: This case highlights the importance of the distinction between resectability and operability, and that patient treatment should be tailored and individualised based on the response to treatment, comorbidities, and underlying tumor biology. PMID:26835191

  19. Double Trouble: A Rare Case of Bilateral Upper Pole Ureteropelvic Junction Obstruction☆

    PubMed Central

    Peters, Craig A.; Pathak, Nirmal

    2014-01-01

    A 16-year-old girl presented with bilateral back pain caused by bilateral upper pole ureteropelvic junction obstructions; an extremely rare phenomenon. Bilateral robotically assisted upper pole pyeloplasties were preformed at the same setting with an excellent clinical response. Although rare, upper pole ureteropelvic junction obstruction is a defined entity that urologists should be aware of. PMID:26958473

  20. Technical considerations in transforaminal endoscopic spine surgery at the thoracolumbar junction: report of 3 cases.

    PubMed

    Telfeian, Albert E; Jasper, Gabriele P; Oyelese, Adetokunbo A; Gokaslan, Ziya L

    2016-02-01

    OBJECTIVE In this study the authors describe the technical considerations and feasibility of transforaminal discectomy and foraminoplasty for the treatment of lumbar radiculopathy in patients who have herniated discs at the thoracolumbar junction. METHODS After institutional review board approval, charts from 3 consecutive patients with lumbar radiculopathy and T12-L1 herniated discs who underwent endoscopic procedures between 2006 and 2014 were reviewed. RESULTS Consecutive cases (n = 1316) were reviewed to determine the incidence and success of surgery performed at the T12-L1 level. Only 3 patients (0.23%) treated with endoscopic surgery for their herniated discs had T12-L1 herniated discs; the rest were lumbar or lumbosacral herniations. For patients with T12-L1 disc herniations, the average preoperative visual analog scale score was 8.3 (indicated in the questionnaire as describing severe and constant pain). The average 1-year postoperative visual analog scale score was 1.7 (indicated in the questionnaire as mild and intermittent pain). CONCLUSIONS Transforaminal endoscopic discectomy and foraminotomy can be used as a safe yet minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a thoracolumbar disc herniation. PMID:26828890

  1. Role of laparoscopy in ureteropelvic junction obstruction with concomitant pathology: a case series study

    PubMed Central

    El-Fayoumi, Abdel-Rahman; Gakis, Georgios; Amend, Bastian; Khairul-Asri, Mohd Ghani; Stenzl, Arnulf; Schwentner, Christian

    2015-01-01

    Introduction Laparoscopic pyeloplasty is considered a standard treatment for ureteropelvic junction obstruction (UPJO). However, the presence of another pathology makes it a more challenging operation and guides the surgeon towards open conversion. In this study, we present our experience in difficult pyeloplasty cases managed by laparoscopy. Material and methods Six patients (4 females and 2 males) with an average age of 44 and a range of 27 to 60 years old, were diagnosed for UPJO. Three were on the left side and 3 on the right side. In addition to UPJO, 2 patients had renal stones, one patient had both renal ptosis and an umbilical hernia, 3 patients had a para-pelvic cyst, hepatomegaly and malrotated kidney, respectively. All patients had a preoperative ultrasound, CT or IVU, and a renal isotope scan. Laparoscopic pyeloplasty was performed according to the dismembered Anderson-Hynes technique with auxiliary maneuver, according to the pathology. Results All patients were treated successfully for UPJO and the concomitant pathologies, except hepatomegaly and malrotation. Mean operative time was 125 minutes and estimated blood loss was <50 ml. Conclusions Laparoscopic pyeloplasty can be performed in difficult situations provided that the surgeon has enough experience with laparoscopy. PMID:26855804

  2. Complex sarcolemmal invaginations mimicking myotendinous junctions in a case of Laing early-onset distal myopathy.

    PubMed

    Reis, Gerald F; de la Motte, Grant; Gooding, Rebecca; Laing, Nigel G; Margeta, Marta

    2015-12-01

    Distal myopathies are a group of clinically and pathologically overlapping muscle diseases that are genetically complex and can represent a diagnostic challenge. Laing early-onset distal myopathy (MPD1) is a form of distal myopathy caused by mutations in the MYH7 gene, which encodes the beta myosin heavy chain protein expressed in type 1 skeletal muscle fibers and cardiac myocytes. Here, we present a case of genetically confirmed MPD1 with a typical clinical presentation but distinctive light microscopic and ultrastructural findings on muscle biopsy. A 39-year-old professional male cellist presented with a bilateral foot drop that developed by age 8; analysis of the family pedigree showed an autosomal dominant pattern of inheritance. The physical exam demonstrated bilateral weakness of ankle dorsiflexors, toe extensors and finger extensors; creatine kinase level was normal. Biopsy of the quadriceps femoris muscle showed predominance and hypotrophy of type 1 fibers, hybrid fibers with co-expression of slow and fast myosin proteins (both in highly atrophic and normal size range), moth-eaten fibers and mini-cores, lack of rimmed vacuoles and rare desmin-positive eosinophilic sarcoplasmic inclusions. In addition to these abnormalities often observed in MPD1, the biopsy demonstrated frequent clefted fibers with complex sarcolemmal invaginations; on ultrastructural examination, these structures closely mimicked myotendinous junctions but were present away from the tendon and were almost exclusively found in type 1 fibers. Sequencing analysis of the MYH7 gene in the index patient and other affected family members demonstrated a previously described heterozygous c.4522_4524delGAG (p.Glu1508del) mutation. This case widens the pathologic spectrum of MPD1 and highlights the pathologic and clinical variability that can accompany the same genetic mutation, suggesting a significant role for modifier genes in MPD1 pathogenesis. PMID:26094647

  3. Technology Solutions Case Study: New Insights for Improving the Designs of Flexible Duct Junction Boxes

    SciTech Connect

    2014-01-01

    In this project, IBACOS explored the relationships between pressure and physical configurations of flexible duct junction boxes by using computational fluid dynamics simulations to predict individual box parameters and total system pressure, thereby ensuring improved HVAC performance.

  4. The posterior pleural junction line in pneumoconiosis. A report of 3 cases with thickening.

    PubMed

    Thomas, R G; Sluis-Cremer, G K; Solomon, A

    1987-06-20

    Disease may change the position or cause thickening or distortion of the posterior pleural junction line. Pleural changes associated with silica or asbestos exposure may also result in radiologically recognisable thickening of the line. Three examples are presented. PMID:3603276

  5. Occult Congenital Ureteropelvic Junction Obstruction in Two Adults Presenting with Collecting System Rupture After Blunt Renal Trauma: A Case Report Series

    PubMed Central

    Hoffner, Haley E.; Dagrosa, Lawrence M.; Pais, Vernon M.

    2015-01-01

    Abstract We report two adult cases of congenital ureteropelvic junction obstruction detected incidentally in the setting of blunt abdominal trauma. CT images are provided to describe the presentation, while review of the literature and management of renal trauma are discussed.

  6. Giant hydronephrosis due to ureteropelvic junction obstruction: A rare case report, and a review of the literature

    PubMed Central

    WANG, QI-FEI; ZENG, GUANG; ZHONG, LIN; LI, QUAN-LIN; CHE, XIANG-YU; JIANG, TAO; ZHANG, ZHI-WEI; ZHENG, WEI; TANG, QI-ZHEN; CHEN, FENG; WANG, KE-NAN

    2016-01-01

    The hydronephrotic kidney, resulting from a ureteropelvic junction obstruction (UPJO), presents commonly as a clinical condition, with the presence of usually no more than 1–2 liters in the collecting system, but a very small number of cases of giant hydronephroses (GHs) has been reported in adults. A GH is defined as the adult renal pelvis containing >1 liter of urine, or at least 1.5% of the body weight. In the majority of cases, the range of the hydronephrotic kidney remains restricted to the renal area. However, the patient described in the present case report had a range for the hydronephrotic kidney which occupied almost the entire abdominal cavity (~24 l), and cases such as these are rarely presented; therefore the aim of the present case study was to document a clear case of GH resulting from UPJO, also accompanied by a review of the current literature. PMID:27330757

  7. Josephson Current in a Gapped Graphene Superconductor/Barrier/Superconductor Junction: Case of Massive Electrons

    NASA Astrophysics Data System (ADS)

    Suwannasit, Tatnatchai; Tang, I.-Ming; Hoonsawat, Rassmidara; Soodchomshom, Bumned

    2011-10-01

    The Josephson effect in a gapped graphene-based superconductor/barrier/superconductor junction is studied. The superconductivity in gapped graphene may be achieved by depositing conventional superconductor on the top of the gapped graphene such as graphene grown on SiC substrate. In gapped graphene system, the carriers exhibit massive Dirac fermions. We focus on the effect of pseudo-Dirac-like mass on the supercurrent. In contrast to that in the gapless graphene superconductor/barrier/superconductor junction, we find that the supercurrent exhibits dependency of the Fermi energy. Also, the massive supercurrent anomalously oscillates as a function of the gate potential. This novel behavior is due to the effect of electrons acquiring mass in gapped graphene.

  8. A Rare Case of Concomitant Intramedullary Gangliocytoma at the Cervicomedullary Junction in Patient with Neuroendocrine Tumor of Lung

    PubMed Central

    Cekinmez, Melih; Kardes, Ozgur; Kayaselcuk, Fazilet

    2016-01-01

    Ganglion cell tumors (GCT) are divided into two subtypes : gangliocytoma and ganglioglioma. Intramedullary gangliocytomas are extremely rare. A 20-year-old male patient with pain of neck, who also had a previously known neuroendocrine tumor of lung, was operated for mass found in the cervicomedullary junction with a presumptive diagnosis of metastases. Only partial resection could be performed. Pathological diagnosis had been reported as gangliocytoma. Only ten cases of intramedullary gangliocytoma have been reported in the literature. Although association with scoliosis and Von Recklinghausen's disease were previously reported in the literature, no gangliocytoma case concomitant with endocrine tumor of lung have been published. Pathological study is the most important diagnostic method for gangliocytomas. Surgical excision is the primary treatment, but difficulty in total surgical tumor resection is the most important problem. PMID:26962423

  9. Cervicothoracic Manual Therapy Plus Exercise Therapy Versus Exercise Therapy Alone in the Management of Individuals With Shoulder Pain: A Multicenter Randomized Controlled Trial.

    PubMed

    Mintken, Paul E; McDevitt, Amy W; Cleland, Joshua A; Boyles, Robert E; Beardslee, Amber R; Burns, Scott A; Haberl, Matthew D; Hinrichs, Lauren A; Michener, Lori A

    2016-08-01

    Study Design Multicenter randomized controlled trial. Background Cervicothoracic manual therapy has been shown to improve pain and disability in individuals with shoulder pain, but the incremental effects of manual therapy in addition to exercise therapy have not been investigated in a randomized controlled trial. Objectives To compare the effects of cervicothoracic manual therapy and exercise therapy to those of exercise therapy alone in individuals with shoulder pain. Methods Individuals (n = 140) with shoulder pain were randomly assigned to receive 2 sessions of cervicothoracic range-of-motion exercises plus 6 sessions of exercise therapy, or 2 sessions of high-dose cervicothoracic manual therapy and range-of-motion exercises plus 6 sessions of exercise therapy (manual therapy plus exercise). Pain and disability were assessed at baseline, 1 week, 4 weeks, and 6 months. The primary aim (treatment group by time) was examined using linear mixed-model analyses and the repeated measure of time for the Shoulder Pain and Disability Index (SPADI), the numeric pain-rating scale, and the shortened version of the Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH). Patient-perceived success was assessed and analyzed using the global rating of change (GROC) and the Patient Acceptable Symptom State (PASS), using chi-square tests of independence. Results There were no significant 2-way interactions of group by time or main effects by group for pain or disability. Both groups improved significantly on the SPADI, numeric pain-rating scale, and QuickDASH. Secondary outcomes of success on the GROC and PASS significantly favored the manual therapy-plus-exercise group at 4 weeks (P = .03 and P<.01, respectively) and on the GROC at 6 months (P = .04). Conclusion Adding 2 sessions of high-dose cervicothoracic manual therapy to an exercise program did not improve pain or disability in patients with shoulder pain, but did improve patient-perceived success at 4 weeks

  10. Spontaneous retrograde migration of ureterovesical junction stone to the kidney; first ever reported case in the English literature in human.

    PubMed

    Khan, Ziauddin; Yaqoob, Alaeddin A; Bhatty, Tanweer A

    2016-01-01

    We present a case of spontaneous retrograde migration of ureterovesical junction stone to the kidney. A 26-year-old Bahraini male, diagnosed with left lower ureteric stone 7 months before this presentation. On his recent presentation, the stone has migrated down but not passed, confirmed on imaging. Operative removal was planned. X-ray kidney ureter bladder (KUB) in the morning of surgery did not reveal stone in the ureter, but the same shadow was seen in the kidney. An urgent computerized tomography-KUB was done, and this confirms the stone has migrated to the kidney. Surgery was canceled, and the stone was dealt with extracorporeal shockwave lithotripsy and was fragmented in the first session. This retrograde migration of lower ureteric stone to the kidney is not reported in the English literature in human before. PMID:27141199

  11. Spontaneous retrograde migration of ureterovesical junction stone to the kidney; first ever reported case in the English literature in human

    PubMed Central

    Khan, Ziauddin; Yaqoob, Alaeddin A.; Bhatty, Tanweer A.

    2016-01-01

    We present a case of spontaneous retrograde migration of ureterovesical junction stone to the kidney. A 26-year-old Bahraini male, diagnosed with left lower ureteric stone 7 months before this presentation. On his recent presentation, the stone has migrated down but not passed, confirmed on imaging. Operative removal was planned. X-ray kidney ureter bladder (KUB) in the morning of surgery did not reveal stone in the ureter, but the same shadow was seen in the kidney. An urgent computerized tomography-KUB was done, and this confirms the stone has migrated to the kidney. Surgery was canceled, and the stone was dealt with extracorporeal shockwave lithotripsy and was fragmented in the first session. This retrograde migration of lower ureteric stone to the kidney is not reported in the English literature in human before. PMID:27141199

  12. Laser etching causing fatigue fracture at the neck–shoulder junction of an uncemented femoral stem: A case report

    PubMed Central

    Jang, Bob; Kanawati, Andrew; Brazil, Declan; Bruce, Warwick

    2013-01-01

    Fatigue fracture of a femoral component in total hip arthroplasty is a rare occurrence but well documented in the literature. It is understood that proximal loosing of a femoral stem with a well fixed stem distally will result in cantilever bending and eventual fatigue fracture of the stem. Other factors which may potentiate a fatigue fracture are material design, implant positioning, and patient characteristics. More recently, laser etching on the femoral neck of an implant has resulted in fatigue fracture. We report a case of a fatigue fracture at the neck–shoulder junction in a well fixed, uncemented, femoral component due to laser etching in the region of high tensile stress. PMID:24403758

  13. Nanotube junctions

    DOEpatents

    Crespi, Vincent Henry; Cohen, Marvin Lou; Louie, Steven Gwon; Zettl, Alexander Karlwalte

    2004-12-28

    The present invention comprises a new nanoscale metal-semiconductor, semiconductor-semiconductor, or metal-metal junction, designed by introducing topological or chemical defects in the atomic structure of the nanotube. Nanotubes comprising adjacent sections having differing electrical properties are described. These nanotubes can be constructed from combinations of carbon, boron, nitrogen and other elements. The nanotube can be designed having different indices on either side of a junction point in a continuous tube so that the electrical properties on either side of the junction vary in a useful fashion. For example, the inventive nanotube may be electrically conducting on one side of a junction and semiconducting on the other side. An example of a semiconductor-metal junction is a Schottky barrier. Alternatively, the nanotube may exhibit different semiconductor properties on either side of the junction. Nanotubes containing heterojunctions, Schottky barriers, and metal-metal junctions are useful for microcircuitry.

  14. Nanotube junctions

    DOEpatents

    Crespi, Vincent Henry; Cohen, Marvin Lou; Louie, Steven Gwon Sheng; Zettl, Alexander Karlwalter

    2003-01-01

    The present invention comprises a new nanoscale metal-semiconductor, semiconductor-semiconductor, or metal-metal junction, designed by introducing topological or chemical defects in the atomic structure of the nanotube. Nanotubes comprising adjacent sections having differing electrical properties are described. These nanotubes can be constructed from combinations of carbon, boron, nitrogen and other elements. The nanotube can be designed having different indices on either side of a junction point in a continuous tube so that the electrical properties on either side of the junction vary in a useful fashion. For example, the inventive nanotube may be electrically conducting on one side of a junction and semiconducting on the other side. An example of a semiconductor-metal junction is a Schottky barrier. Alternatively, the nanotube may exhibit different semiconductor properties on either side of the junction. Nanotubes containing heterojunctions, Schottky barriers, and metal-metal junctions are useful for microcircuitry.

  15. Giant prolactinoma causing cranio-cervical junction instability: a case report.

    PubMed

    Zaben, Malik J A; Harrisson, Stuart E; Mathad, N V

    2011-12-01

    Prolactinomas are common secretory pituitary tumours, usually managed with dopamine agonists. There have previously been case reports of rarer giant prolactinomas causing invasion of surrounding structures. We describe a case report of an exceptionally aggressive giant prolactinoma that eroded the occipital condyles causing cranio-cervical joint instability mandating surgical fixation. PMID:21344972

  16. Spontaneous large renal pelvis hematoma in ureteropelvic junction obstruction presenting as an acute abdomen: Rare case report.

    PubMed

    Sawant, Ajit; Kasat, Gaurav; Pawar, Prakash; Tamhankar, Ashwin

    2016-01-01

    Patients with ureteropelvic junction (UPJ) obstruction can present with flank pain or hematuria. We present 20-year-old male presenting with acute pain in lumbar and right fossa with tenderness and guarding, this case was clinically mimicking general surgical emergency. On computed tomography with urography and angiography, there was 15 cm × 11 cm × 10 cm size non-enhancing hyperdense lesion (average Hounsfield units - +64) in right renal pelvis suggestive of hematoma. Patient's diethylenetriaminepentaacetic acid diuretic renography was suggestive of right kidney glomerular function rate of 48.4 ml/min with the relative function of 43%, Peak to half peak was not achieved. The patient was managed by retrograde ureteropyelography and double J stenting. After 1 month, clot size decreased to 4 cm × 3 cm × 2 cm. The patient had undergone open reduction Anderson hynes dismembered pyeloplasty with the removal of pelvis clot after 6 weeks. We report the first case of UPJ obstruction presenting as an acute abdomen and spontaneous hematuria with large pelvis clot without rupture of the renal pelvis. PMID:27141202

  17. Josephson junction

    DOEpatents

    Wendt, Joel R.; Plut, Thomas A.; Martens, Jon S.

    1995-01-01

    A novel method for fabricating nanometer geometry electronic devices is described. Such Josephson junctions can be accurately and reproducibly manufactured employing photolithographic and direct write electron beam lithography techniques in combination with aqueous etchants. In particular, a method is described for manufacturing planar Josephson junctions from high temperature superconducting material.

  18. Josephson junction

    DOEpatents

    Wendt, J.R.; Plut, T.A.; Martens, J.S.

    1995-05-02

    A novel method for fabricating nanometer geometry electronic devices is described. Such Josephson junctions can be accurately and reproducibly manufactured employing photolithographic and direct write electron beam lithography techniques in combination with aqueous etchants. In particular, a method is described for manufacturing planar Josephson junctions from high temperature superconducting material. 10 figs.

  19. Bimetallic junctions

    NASA Technical Reports Server (NTRS)

    Arcella, F. G.; Lessmann, G. G.; Lindberg, R. A. (Inventor)

    1977-01-01

    The formation of voids through interdiffusion in bimetallic welded structures exposed to high operating temperatures is inhibited by utilizing an alloy of the parent materials in the junction of the parent materials or by preannealing the junction at an ultrahigh temperature. These methods are also used to reduce the concentration gradient of a hardening agent.

  20. Neuroarthropathy of the Wrist in Paraplegia: A Case Report

    PubMed Central

    Shem, Kazuko L

    2006-01-01

    Background/Objective: Neuroarthropathy, also known as Charcot joint, is most commonly seen in the spine and other weight-bearing joints in individuals with spinal cord injury (SCI). It is rarely seen in the joints of the upper extremities because the pathophysiology of the neuroarthropathy is thought to be significant repetitive trauma such as with weight bearing in an insensate joint. Methods: Case report of neuroarthropathy in the wrist of a 46-year-old man with a 30-year history of T4 paraplegia caused by ependymoma. Results: The patient recently developed a nonpainful swelling in the left wrist, which had decreased sensation since the time of his initial SCI. Radiological evaluation showed marked degenerative changes consistent with neuroarthropathy. A magnetic resonance image of the spine showed spinal cord atrophy at the cervicothoracic junction. Conclusions: This case shows an unusual presentation of a neuroarthropathy in a wrist in an individual with functional paraplegia. Because the treatment options for neuroarthropathy in the upper extremity in individuals with SCI are limited, early diagnosis is crucial to implement conservative management before significant destruction of the joint occurs. PMID:17044396

  1. Gap Junctions

    PubMed Central

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2013-01-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

  2. Singular layers for transmission problems in thin shallow shell theory: Rigid junction case

    NASA Astrophysics Data System (ADS)

    Merabet, Ismail; Chacha, D. A.; Nicaise, S.

    2010-02-01

    In this Note we study two-dimensional transmission problems for the linear Koiter's model of an elastic multi-structure composed of two thin shallow shells. This work enters in the framework of singular perturbation of problems depending on a small parameter ɛ. The formal limit problem fails to give a solution satisfying all boundary and transmission conditions; it gives only the outer solution. Both in the case of regular or singular loadings, we derive a limit problem which allows us to determine the inner solution explicitly.

  3. Video-assisted treatment of thoracolumbar junction fractures using a specific distractor for reduction: prospective study of 50 cases.

    PubMed

    Le Huec, Jean-Charles; Tournier, C; Aunoble, S; Madi, K; Leijssen, Ph

    2010-03-01

    Posterior instrumentation allows good osteosynthesis for thoracolumbar junction fractures. However, in approximately 20% of cases, anterior bone defects may persist, leading to pseudoarthrosis and loss of reduction. Anterior approaches can circumvent this drawback, but they are considered aggressive with a high rate of complications. The advent of the endoscopic mini-invasive techniques has led to a reduction in the number of complications while maintaining the same consolidation rate. Nevertheless, poor restitution of anatomic curves is a reproach for this technique. This prospective study reports clinical and radiological result of 50 patients (19 women and 31 men) operated between April 2000 and March 2006 with a video-assisted anterior approach using an endodistractor for reduction and consequent insertion of the implant. There were A3 (n = 44), A2 (n = 2), A1 (n = 3) and C1 (n = 1) fractures (Magerl classification). The specific system for fracture reduction was used in the last 39 cases of this series. A Pyramesh cage (Medtronic, Memphis, USA) was used in 15 patients, a peek cage (Creaspine, Bordeaux, France) in 30 patients and a tricortical graft in 5 patients. Standard X-rays and CT scan were performed pre-operatively. Kyphosis, and angulations were measured pre-, per- and post-operatively. Mean immediate postoperative gain in localized kyphosis was 12.18 degrees and mean gain at last follow-up was 11.71 degrees. Mean immediate postoperative gain in RA was 13.24 degrees and remained identical at last follow-up. Five patients had a transient pulmonary atelectasia and there was one pulmonary infection. No neurological complication occurred. Fracture reduction is comparable to the best thoracotomy series while limiting approach-related complications. PMID:19701654

  4. Video-assisted treatment of thoracolumbar junction fractures using a specific distractor for reduction: prospective study of 50 cases

    PubMed Central

    Tournier, C.; Aunoble, S.; Madi, K.; Leijssen, Ph.

    2009-01-01

    Posterior instrumentation allows good osteosynthesis for thoracolumbar junction fractures. However, in approximately 20% of cases, anterior bone defects may persist, leading to pseudoarthrosis and loss of reduction. Anterior approaches can circumvent this drawback, but they are considered aggressive with a high rate of complications. The advent of the endoscopic mini-invasive techniques has led to a reduction in the number of complications while maintaining the same consolidation rate. Nevertheless, poor restitution of anatomic curves is a reproach for this technique. This prospective study reports clinical and radiological result of 50 patients (19 women and 31 men) operated between April 2000 and March 2006 with a video-assisted anterior approach using an endodistractor for reduction and consequent insertion of the implant. There were A3 (n = 44), A2 (n = 2), A1 (n = 3) and C1 (n = 1) fractures (Magerl classification). The specific system for fracture reduction was used in the last 39 cases of this series. A Pyramesh cage (Medtronic, Memphis, USA) was used in 15 patients, a peek cage (Creaspine, Bordeaux, France) in 30 patients and a tricortical graft in 5 patients. Standard X-rays and CT scan were performed pre-operatively. Kyphosis, and angulations were measured pre-, per- and post-operatively. Mean immediate postoperative gain in localized kyphosis was 12.18° and mean gain at last follow-up was 11.71°. Mean immediate postoperative gain in RA was 13.24° and remained identical at last follow-up. Five patients had a transient pulmonary atelectasia and there was one pulmonary infection. No neurological complication occurred. Fracture reduction is comparable to the best thoracotomy series while limiting approach-related complications. PMID:19701654

  5. [Two cases of lateral approach for thoraco-lumbar junctional lesions: experiment of Kaneda's device].

    PubMed

    Nishida, K; Ueda, S; Matsumoto, K; Okada, M

    1992-01-01

    Case 1: a 32-year-old woman was admitted to our hospital with major complaints of gait disturbance and urinary incontinence. The tendon reflex was markedly increased in the bilateral lower extremities, and both Babinski's reflex and clonus were strongly positive. Myelography revealed complete block in the 10th thoracic vertebral level. On April 15, 1989, a tumor in the vertebral region was exposed and excised via a right posterolateral approach. Kaneda's device was used for internal fixation. The tumor was diagnosed as myeloma histologically. The postoperative course was uneventful. Postoperatively, the patient became capable of walking by herself. Case 2: an 18-year-old woman was admitted because of burst fractures of the 1st and 2nd lumbar vertebrae due to a traffic accident in January of 1989. The fractured bones had been manually repositioned and fixed with plaster. However, the patient still had gait disturbance (intermittent claudication). Myelography revealed a complete block in the 2nd lumbar vertebral region. On May 7, the vertebral foramen was opened via a left anterolateral approach, and internal fixation was performed using Kaneda's device. Postoperatively, the patient recovered full ability to walk, and returned to normal social activity. From our experience, it is thought to be useful to employ a right posterolateral approach to the thoracic vertebrae, and a left anterolateral approach to the lumbar vertebrae. We used Kaneda's device for internal fixation, successfully. However, this device has the following disadvantages; (1) there are few plates designed for females, whose vertebrae are small, (2) it is difficult to preserve the arteries of Adamkiewicz and (3) postoperative MRI becomes impossible. PMID:1738429

  6. Correlations between molecular structure and single-junction conductance: a case study with oligo(phenylene-ethynylene)-type wires.

    PubMed

    Kaliginedi, Veerabhadrarao; Moreno-García, Pavel; Valkenier, Hennie; Hong, Wenjing; García-Suárez, Víctor M; Buiter, Petra; Otten, Jelmer L H; Hummelen, Jan C; Lambert, Colin J; Wandlowski, Thomas

    2012-03-21

    The charge transport characteristics of 11 tailor-made dithiol-terminated oligo(phenylene-ethynylene) (OPE)-type molecules attached to two gold electrodes were studied at a solid/liquid interface in a combined approach using an STM break junction (STM-BJ) and a mechanically controlled break junction (MCBJ) setup. We designed and characterized 11 structurally distinct dithiol-terminated OPE-type molecules with varied length and HOMO/LUMO energy. Increase of the molecular length and/or of the HOMO-LUMO gap leads to a decrease of the single-junction conductance of the linearly conjugate acenes. The experimental data and simulations suggest a nonresonant tunneling mechanism involving hole transport through the molecular HOMO, with a decay constant β = 3.4 ± 0.1 nm(-1) and a contact resistance R(c) = 40 kΩ per Au-S bond. The introduction of a cross-conjugated anthraquinone or a dihydroanthracene central unit results in lower conductance values, which are attributed to a destructive quantum interference phenomenon for the former and a broken π-conjugation for the latter. The statistical analysis of conductance-distance and current-voltage traces revealed details of evolution and breaking of molecular junctions. In particular, we explored the effect of stretching rate and junction stability. We compare our experimental results with DFT calculations using the ab initio code SMEAGOL and discuss how the structure of the molecular wires affects the conductance values. PMID:22352944

  7. Carbon nanotube intramolecular junctions

    NASA Astrophysics Data System (ADS)

    Yao, Zhen; Postma, Henk W. Ch.; Balents, Leon; Dekker, Cees

    1999-11-01

    The ultimate device miniaturization would be to use individual molecules as functional devices. Single-wall carbon nanotubes (SWNTs) are promising candidates for achieving this: depending on their diameter and chirality, they are either one-dimensional metals or semiconductors. Single-electron transistors employing metallic nanotubes and field-effect transistors employing semiconducting nanotubes have been demonstrated. Intramolecular devices have also been proposed which should display a range of other device functions. For example, by introducing a pentagon and a heptagon into the hexagonal carbon lattice, two tube segments with different atomic and electronic structures can be seamlessly fused together to create intramolecular metal-metal, metal-semiconductor, or semiconductor-semiconductor junctions. Here we report electrical transport measurements on SWNTs with intramolecular junctions. We find that a metal-semiconductor junction behaves like a rectifying diode with nonlinear transport characteristics that are strongly asymmetric with respect to bias polarity. In the case of a metal-metal junction, the conductance appears to be strongly suppressed and it displays a power-law dependence on temperatures and applied voltage, consistent with tunnelling between the ends of two Luttinger liquids. Our results emphasize the need to consider screening and electron interactions when designing and modelling molecular devices. Realization of carbon-based molecular electronics will require future efforts in the controlled production of these intramolecular nanotube junctions.

  8. The behavior of series resistance of a p-n junction: the diode and the solar cell cases

    NASA Astrophysics Data System (ADS)

    Bueno, Poliana H.; Costa, Diogo F.; Eick, Alexander; Carvalho, André; Monteiro, Davies W. L.

    2016-03-01

    This paper presents a comparison of the impact of the internal parasitic series resistance of a p-n junction, as seen from the microelectronics and photovoltaic communities. The elusive thermal behavior of the aforementioned resistance gave this work its origin. Each community uses a different approach to interpret the operational current-voltage behavior of a p-n junction, which might lead to confusion, since scientists and engineers of these two realms seldom interact. An improvement in the understanding of the different approaches will help one to better model the performance of devices based on p-n junctions and therefore it will favor the performance predictions of photovoltaic cells. For diodes, series resistance is usually determined from a specific forward-bias region of the I-V curve on a semi-logarithmic scale. However, in Photovoltaics this region is not commonly reported and therefore other methods to determine Rs are employed. We mathematically modeled an experimentally obtained I-V curve with various pairs of the ideality factor and Rs and found that more than one pair accurately synthesizes the measured curve. We can conclude that the reported series resistance not only depends on physical parameters, e.g. temperature or irradiance, but also on fitting parameters, i.e. the ideality factor. Generally the behavior of a p-n junction depends on its operating conditions and electrical modeling.

  9. Preventing proximal junctional failure in long segmental instrumented cases of adult degenerative scoliosis using a multilevel stabilization screw technique

    PubMed Central

    Sandquist, Lee; Carr, Daniel; Tong, Doris; Gonda, Roger; Soo, Teck M.

    2015-01-01

    Background: The authors sought to demonstrate the safety and effectiveness of the multilevel stabilization screw (MLSS) technique in decreasing the incidence of proximal junctional failure in long segmental instrumented fusions for adult degenerative scoliosis. Methods: Institutional review board approval was obtained and all patients with adult spinal deformity who underwent the MLSS technique were analyzed. A neuro-radiologist and spine-focused neurosurgeon not involved with the surgical treatment performed radiographic analysis. Proximal junctional angle was defined as the caudal endplate of the upper instrumented vertebra (UIV) to the cephalad endplate of two supradjacent vertebrae above the UIV. The UIV is defined as the most cephalad vertebra completed captured by the instrumentation. Abnormal proximal junctional kyphosis (PJK) was defined as proximal junctional sagittal Cobb angle >10 degrees and proximal junction sagittal Cobb angle at least 10 degrees greater than the preoperative measurement. The presence of both is criteria necessary to be considered abnormal. Results: Twenty patients with degenerative scoliosis underwent the MLSS technique with the upper-instrumented vertebrae in the proximal thoracic spine. Fifteen patients met inclusion criteria with greater than 12 months radiographic and clinical follow up. Three patients were excluded due to lack of follow up imaging and two patients were excluded due to the inability to measure the UIV. Age range was 44–84 years with a mean of 66. Eleven of the 15 patients were over the age of 60 at the time of surgery. The male-to-female ratio was 4:11. Body mass index (BMI) range was 24–44 with a mean of 31.5 units. The follow up period ranged from 14 to 58 months with an average follow up of 30 months. The mean change in Cobb angle at the proximal junction was 4.00 degrees with a range from -0.92 to 9.13 degrees. There were no fractures or instrumentation failures at or near the proximal junction. There was

  10. [Concurrent association of reirradiation therapy with everolimus for lymph node metastasis of gastroesophageal junction cancer: a case report].

    PubMed

    Pernin, V; Beuzeboc, P; Peurien, D; Louvet, C; Kirova, Y

    2014-11-01

    Advanced gastric cancer or gastro-oesophageal junction cancer after a failure of first line chemotherapy have poor outcome. Hereby, we present the first patient treated by radiotherapy with concurrent everolimus, a mTor inhibitor, for a reirradiation of metastasis invading left axillary, infraclavicular and supraclavicular lymph nodes in progression despite several lines of chemotherapy. After 6 months of follow-up, this association provided a satisfactory anti-tumor efficiency and tolerance. Nevertheless, clinical trials are needed in order to confirm this strategy for the treatment of gastric cancer metastasis. PMID:24981410

  11. [A Case of HER2-Positive Esophagogastric Junction Cancer with Perforation Curatively Resected after Neoadjuvant Chemotherapy plus Trastuzumab].

    PubMed

    Toshima, Hirokazu; Hisamatsu, Atsushi; Shimada, Ken; Saito, Mitsuo; Suzuki, Michitaka; Matsukawa, Masaaki; Inoue, Haruhiro

    2016-06-01

    A 60-year-old man was diagnosed with adenocarcinoma of the esophagogastric junction with lymph node metastasis along the left gastric artery. The clinical stage was determined to be T4b, N1, M0, Stage IIIB, and a neoadjuvant chemotherapy (NAC)regimen of capecitabine/CDDP plus trastuzumab was selected for treatment. Before 3 courses of chemotherapy, the patient developed perforated gastric cancer. With conservative therapy, we were able to obtain closure of the perforation without affecting the curability of the cancer. We changed the chemotherapy regimen to S-1/CDDP plus trastuzumab, and the patient underwent curative resection. PMID:27306816

  12. Spontaneous intracranial hypotension following epidural anesthesia: a case report.

    PubMed

    An, X; Wu, S; He, F; Li, C; Fang, X

    2016-05-01

    We report a case of refractory spontaneous intracranial hypotension (SIH) following epidural anesthesia. In this case, typical clinical symptoms and concomitant use of regional anesthesia led to the misdiagnosis of SIH as post-dural puncture headache (PDPH). A 56-year-old man received a successful appendectomy under epidural anesthesia performed at a T11-T12 intravertebral space. About 20 h later, the patient started complaining about orthostatic headache when getting up from his lying position, then a PDPH was diagnosed. However, the patient did not respond well to conservative treatment. Three months later, the first epidural blood patch was performed at the L3-L4 level, however, the patient still had an orthostatic headache. Five days later, spine magnetic resonance imaging showed multiple meningeal diverticulum in the cervicothoracic junction, and computerized tomography myelography demonstrated a C5-C6 spinal dural tear suggesting cerebrospinal fluid leaks. Finally, the patient was diagnosed as SIH and received a second epidural blood patch at the T2-T3 level and responded with improvements in symptomatology. The patient was then discharged, and at a 2-year follow-up, he had fully recovered except for some remaining neck stiffness. This case illustrates that SIH was misdiagnosed as PDPH because of the common clinical symptoms and potentially confounding events (epidural/spinal anesthesia and assumption that it was a case of PDPH). It is important to carefully observe patients in such conditions and promptly conduct suitable diagnostic tests. For a successful treatment of SIH, a timely epidural blood patch should be considered as soon as the diagnosis is established. PMID:26939569

  13. Intraoperative somatosensory evoked potential recovery following opening of the fourth ventricle during posterior fossa decompression in Chiari malformation: case report.

    PubMed

    Grossauer, Stefan; Koeck, Katharina; Vince, Giles H

    2015-03-01

    The most appropriate surgical technique for posterior fossa decompression in Chiari malformation (CM) remains a matter of debate. Intraoperative electrophysiological studies during posterior fossa decompression of Type I CM (CM-I) aim to shed light on the entity's pathomechanism as well as on the ideal extent of decompression. The existing reports on this issue state that significant improvement in conduction occurs after craniotomy in all cases, but additional durotomy contributes a further improvement in only a minority of cases. This implies that craniotomy alone might suffice for clinical improvement without the need of duraplasty or even subarachnoid manipulation at the level of the craniocervical junction. In contrast to published data, the authors describe the case of a 32-year-old woman who underwent surgery for CM associated with extensive cervicothoracic syringomyelia and whose intraoperative somatosensory evoked potentials (SSEPs) did not notably improve after craniotomy or following durotomy; rather, they only improved after opening of the fourth ventricle and restoration of CSF flow through the foramen of Magendie. Postoperatively, the patient recovered completely from her preoperative neurological deficits. To the authors' knowledge, this is the first report of significant SSEP recovery after opening the fourth ventricle in the decompression of a CM-I. The electrophysiological and operative techniques are described in detail and the findings are discussed in the light of available literature. The authors conclude that there might be a subset of CM-I patients who require subarachnoid dissection at the level of the craniocervical junction to benefit clinically. Prospective studies with detailed electrophysiological analyses seem warranted to answer the question regarding the best surgical approach in CM-I decompression. PMID:25526275

  14. The. Thoma Ionescu - Victor Gomoiu Procedure: Cervicothoracic Sympathectomy for Angina Pectoris. The First Surgical Attempt to Treat the Coronary Heart Disease.

    PubMed

    Vasilescu, Cătălin; Salmen, Monica; Bobocea, Andrei

    2016-01-01

    Cervicothoracic Sympathectomy is a common indication in the treatment of Raynaud Syndrome, Palmer Hyperhidrosis or Acute Ischemia of the superior limb. Nonetheless, almost a century ago it represented one of the first innovative attempts in curing coronary heart disease. Nowadays, this indication is no more than a footnote in a volume on the History of Medicine, and a trivia fact for medical history enthusiasts. The operation's history is rather conflicting. A young Romaninan surgeon, Victor Gomoiu seems to have come up with the idea, in the early 20th century. However, his contribution remains unknown, after his successful collaboration with the famous surgeon and anatomist, Thoma Ionescu unfortunately turns into a dispute. This procedure was once thought cutting-edge. Furthermore it is the starting point for cardiovascular surgery. Whoever sparked the idea, gains an important place in the hall of fame of international surgery, that is why it is important to know its creator. PMID:27544937

  15. Confocal Annular Josephson Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Monaco, Roberto

    2016-04-01

    The physics of Josephson tunnel junctions drastically depends on their geometrical configurations and here we show that also tiny geometrical details play a determinant role. More specifically, we develop the theory of short and long annular Josephson tunnel junctions delimited by two confocal ellipses. The behavior of a circular annular Josephson tunnel junction is then seen to be simply a special case of the above result. For junctions having a normalized perimeter less than one, the threshold curves in the presence of an in-plane magnetic field of arbitrary orientations are derived and computed even in the case with trapped Josephson vortices. For longer junctions, a numerical analysis is carried out after the derivation of the appropriate motion equation for the Josephson phase. We found that the system is modeled by a modified and perturbed sine-Gordon equation with a space-dependent effective Josephson penetration length inversely proportional to the local junction width. Both the fluxon statics and dynamics are deeply affected by the non-uniform annulus width. Static zero-field multiple-fluxon solutions exist even in the presence of a large bias current. The tangential velocity of a traveling fluxon is not determined by the balance between the driving and drag forces due to the dissipative losses. Furthermore, the fluxon motion is characterized by a strong radial inward acceleration which causes electromagnetic radiation concentrated at the ellipse equatorial points.

  16. Confocal Annular Josephson Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Monaco, Roberto

    2016-09-01

    The physics of Josephson tunnel junctions drastically depends on their geometrical configurations and here we show that also tiny geometrical details play a determinant role. More specifically, we develop the theory of short and long annular Josephson tunnel junctions delimited by two confocal ellipses. The behavior of a circular annular Josephson tunnel junction is then seen to be simply a special case of the above result. For junctions having a normalized perimeter less than one, the threshold curves in the presence of an in-plane magnetic field of arbitrary orientations are derived and computed even in the case with trapped Josephson vortices. For longer junctions, a numerical analysis is carried out after the derivation of the appropriate motion equation for the Josephson phase. We found that the system is modeled by a modified and perturbed sine-Gordon equation with a space-dependent effective Josephson penetration length inversely proportional to the local junction width. Both the fluxon statics and dynamics are deeply affected by the non-uniform annulus width. Static zero-field multiple-fluxon solutions exist even in the presence of a large bias current. The tangential velocity of a traveling fluxon is not determined by the balance between the driving and drag forces due to the dissipative losses. Furthermore, the fluxon motion is characterized by a strong radial inward acceleration which causes electromagnetic radiation concentrated at the ellipse equatorial points.

  17. Fractional order junctions

    NASA Astrophysics Data System (ADS)

    Machado, J. Tenreiro

    2015-01-01

    Gottfried Leibniz generalized the derivation and integration, extending the operators from integer up to real, or even complex, orders. It is presently recognized that the resulting models capture long term memory effects difficult to describe by classical tools. Leon Chua generalized the set of lumped electrical elements that provide the building blocks in mathematical models. His proposal of the memristor and of higher order elements broadened the scope of variables and relationships embedded in the development of models. This paper follows the two directions and proposes a new logical step, by generalizing the concept of junction. Classical junctions interconnect system elements using simple algebraic restrictions. Nevertheless, this simplistic approach may be misleading in the presence of unexpected dynamical phenomena and requires including additional "parasitic" elements. The novel γ -junction includes, as special cases, the standard series and parallel connections and allows a new degree of freedom when building models. The proposal motivates the search for experimental and real world manifestations of the abstract conjectures.

  18. Cervical Synovial Cyst Causing Cervical Radiculomyelopathy: Case Report and Review of the Literature.

    PubMed

    Corredor, José A; Quan, Gerald

    2015-08-01

    Study Design Case report. Objective Synovial cysts in the subaxial cervical spine are rare and are most commonly reported at the cervicothoracic junction. Only six cases of symptomatic C5-C6 synovial cysts have been reported in the literature; the condition is usually treated with decompressive laminectomy. We present a patient with a synovial cyst arising from the C5-C6 facet joint, associated with spondylolisthesis, and causing radiculomyelopathy. The patient was treated with a posterior excision of the cyst, decompressive laminectomy, and fusion. Methods A 67-year-old man had vertebral canal stenosis at C5-C6 secondary to a synovial cyst and spondylolisthesis with symptoms and signs of radiculopathy and myelopathy. Surgical management involved C5-C6 posterior decompressive laminectomy and excision of the cyst and C4-C6 instrumented fusion with lateral mass screws and rods. A literature review of symptomatic cervical synovial cysts is presented. Results The imaging studies identified grade I spondylolisthesis and a 3.3 × 4.3-mm extradural lentiform-like mass associated with focal compression of the spinal cord and exiting the C6 nerve root. After the surgery, the patient had an immediate full recovery and was asymptomatic by the 6-month examination. No operative complications were reported. The histologic report confirmed the presence of a synovial cyst. Conclusions C5-C6 is an unusual localization for symptomatic synovial cysts. Similar cases reported in the literature achieved excellent results after cyst excision and decompressive laminectomy. Because spondylolisthesis plus laminectomy are risk factors for segmental instability in the cervical spine, we report a case of a C5-C6 facet synovial cyst successfully treated with posterior laminectomy and C4-C6 fusion. PMID:26225291

  19. Cervical Synovial Cyst Causing Cervical Radiculomyelopathy: Case Report and Review of the Literature

    PubMed Central

    Corredor, José A.; Quan, Gerald

    2014-01-01

    Study Design Case report. Objective Synovial cysts in the subaxial cervical spine are rare and are most commonly reported at the cervicothoracic junction. Only six cases of symptomatic C5–C6 synovial cysts have been reported in the literature; the condition is usually treated with decompressive laminectomy. We present a patient with a synovial cyst arising from the C5–C6 facet joint, associated with spondylolisthesis, and causing radiculomyelopathy. The patient was treated with a posterior excision of the cyst, decompressive laminectomy, and fusion. Methods A 67-year-old man had vertebral canal stenosis at C5–C6 secondary to a synovial cyst and spondylolisthesis with symptoms and signs of radiculopathy and myelopathy. Surgical management involved C5–C6 posterior decompressive laminectomy and excision of the cyst and C4–C6 instrumented fusion with lateral mass screws and rods. A literature review of symptomatic cervical synovial cysts is presented. Results The imaging studies identified grade I spondylolisthesis and a 3.3 × 4.3-mm extradural lentiform-like mass associated with focal compression of the spinal cord and exiting the C6 nerve root. After the surgery, the patient had an immediate full recovery and was asymptomatic by the 6-month examination. No operative complications were reported. The histologic report confirmed the presence of a synovial cyst. Conclusions C5–C6 is an unusual localization for symptomatic synovial cysts. Similar cases reported in the literature achieved excellent results after cyst excision and decompressive laminectomy. Because spondylolisthesis plus laminectomy are risk factors for segmental instability in the cervical spine, we report a case of a C5–C6 facet synovial cyst successfully treated with posterior laminectomy and C4–C6 fusion. PMID:26225291

  20. A power balance model for converging and diverging flow junctions

    SciTech Connect

    Guffey, S.E. ); Fraser, D.A. )

    1989-01-01

    The authors propose that pressures across a junction of flows are best described by potential, kinetic, and dissipated (lost) power. It is demonstrated that differences in Bernoulli constants up- and downstream of junctions are not proportional to energy losses even in the trivial case of zero junction losses.

  1. Disordered graphene Josephson junctions

    NASA Astrophysics Data System (ADS)

    Muñoz, W. A.; Covaci, L.; Peeters, F. M.

    2015-02-01

    A tight-binding approach based on the Chebyshev-Bogoliubov-de Gennes method is used to describe disordered single-layer graphene Josephson junctions. Scattering by vacancies, ripples, or charged impurities is included. We compute the Josephson current and investigate the nature of multiple Andreev reflections, which induce bound states appearing as peaks in the density of states for energies below the superconducting gap. In the presence of single-atom vacancies, we observe a strong suppression of the supercurrent, which is a consequence of strong intervalley scattering. Although lattice deformations should not induce intervalley scattering, we find that the supercurrent is still suppressed, which is due to the presence of pseudomagnetic barriers. For charged impurities, we consider two cases depending on whether the average doping is zero, i.e., existence of electron-hole puddles, or finite. In both cases, short-range impurities strongly affect the supercurrent, similar to the vacancies scenario.

  2. Ballistic bipolar junctions in chemically gated graphene ribbons

    PubMed Central

    Baringhaus, Jens; Stöhr, Alexander; Forti, Stiven; Starke, Ulrich; Tegenkamp, Christoph

    2015-01-01

    The realization of ballistic graphene pn-junctions is an essential task in order to study Klein tunneling phenomena. Here we show that intercalation of Ge under the buffer layer of pre-structured SiC-samples succeeds to make truly nano-scaled pn-junctions. By means of local tunneling spectroscopy the junction width is found to be as narrow as 5 nm which is a hundred times smaller compared to electrically gated structures. The ballistic transmission across the junction is directly proven by systematic transport measurements with a 4-tip STM. Various npn- and pnp-junctions are studied with respect to the barrier length. The pn-junctions are shown to act as polarizer and analyzer with the second junction becoming transparent in case of a fully ballistic barrier. This can be attributed to the almost full suppression of electron transmission through the junction away from normal incidence. PMID:25898259

  3. Adeno-carcinoma of the pharyngo-oesophageal junction and cervical oesophagus in a patient with an oesophagus lined entirely by columnar epithelium report of a case treated by photodynamic therapy (PDT).

    PubMed

    Moghissi, K; Dixon, Kate; Campbell, Anne

    2008-09-01

    A case of adenocarcinoma in the pharyngo oesophageal junction extending to the upper cervical oesophagus is described. In this case the neo-plastic changes had occurred from columnar epithelium of gastric and intestinal type: Barrett's oesophagus. The Barrett's mucosa involved the whole length of the oesophagus. Because of the general condition of the patient and advanced stage of the tumour surgical treatment was considered inappropriate. Endoscopic Photofrin Photodynamic Therapy was used with good palliation of dysphagia. The patient survived for 9 months, dying form carcinomatosis and oesophago-airway fistula. As far as can be documented only one such case has been previously reported in the literature. PMID:19356659

  4. Osteopathia striata with cranial sclerosis (OSCS): review of the literature and case report demonstrating challenges of spinal fusion after trauma.

    PubMed

    Katsevman, Gennadiy A; Turner, Ryan C; Lucke-Wold, Brandon P; Sedney, Cara L; Bhatia, Sanjay

    2016-06-01

    Osteopathia striata with cranial sclerosis (OSCS) is a rare but well-described pathology characterized by abnormalities in bone deposition in the axial and cranial skeleton as well as other abnormalities and associated deficits. These skeletal abnormalities can lead to significant intra-operative challenges for the surgeon and influence outcomes for the patient. In this report, we present a case of a patient with OSCS who was involved in a traumatic motor vehicle crash and underwent posterior cervico-thoracic fusion for a T4 chance fracture. Bony abnormalities in the cervico-thoracic spine presented a significant operative challenge due to alterations in bony anatomy and bone architecture. This case serves as an example of the challenges that the spine surgeon faces when dealing with OSCS, and highlights the differences between OSCS and commoner skeletal hyperplasias such as osteopetrosis. PMID:27068044

  5. Extended generation profile - E.B.I.C model application in the case of a PN junction

    NASA Astrophysics Data System (ADS)

    Guermazi, S.; Toureille, A.; Grill, C.; El Jani, B.

    2000-01-01

    We have developed a model for the calculation of the induced current due to an electron beam with an extended generation profile. Added to the absorbed and diffuse electrons in the depth distribution, the generation profile takes into account the lateral diffusion. The analytical expression of the electron beam induced current (EBIC) is obtained by solving the continuity equation in permanent regime by the Green function method. The induced current profile, obtained in the case of a ternary component (Ga{0.7}Al{0.3}As:N^+/Ga{0.7}Al{0.3}As:P) sulfur doped and prepared by organometallic compounds phase vapor epitaxy method, is compared to the theoretical profiles whose analytical expressions are given by Van Roosbroeck and Bresse. The experimental current profile, measured by S.E.M provided us to calculate the diffusion length of the minority carriers: L_p=1 μm in the N region and L_n=1.80 μm in the P region of the ternaire component. The theoretical curve obtained from the proposed model is in good agreement with the experimental one for a surface recombination velocity of 10^6 cm s^{-1}. Our results are found to be consistent compared to those obtained by other experimental techniques using the same samples. Nous avons développé un modèle de calcul du courant induit par un faisceau d'électrons avec un profil de génération élargi. Le profil de génération prend en compte la répartition spatiale de la diffusion et de l'absorption des électrons. L'expression analytique du courant induit (E.B.I.C) est déterminée par résolution de l'équation de continuité en régime permanent par la méthode des fonctions de Green. Le profil de courant induit obtenu dans le cas d'une jonction PN (Ga{0,7}Al{0,3}As:N^+/Ga{0,7}Al{0,3}As:P) dopée par le soufre et préparée par épitaxie à phase vapeur organo-métallique, est comparé au profil de courant théorique dont l'expression analytique est explicitée par Van Roosbroeck et Bresse. Le profil expérimental de

  6. New Phenomena in Josephson SINIS Junctions

    NASA Astrophysics Data System (ADS)

    Volkov, A. F.

    1995-06-01

    We analyze the dc and ac Josephson effects in SaINISb junctions in which an additional bias current flows in the N layer. The case of low temperatures and voltages \\(eV, T<<Δ\\) is considered in the dirty limit. We show that the critical Josephson current may change sign, and the considered SINIS junction may become a π junction if the voltage drop across the N/Sa interface exceeds a certain value \\(eVN>Δ/2\\). The ac Josephson effect may arise even if the current flows only through the N/Sa interface, whereas the current through the Sb/N interface is absent.

  7. Neuromuscular junctional disorders.

    PubMed

    Girija, A S; Ashraf, V V

    2008-07-01

    Neuromuscular junctional disorders (NMJ) in children are distinct entity. They may be acquired or hereditary. They pose problem in diagnosis because of the higher occurrence of sero negative Myasthenia Gravis (MG) cases in children. The identity of MusK antibody positivity in a good percentage of sero negative cases further adds to problems in diagnosis. The Congenital Myasthenic Syndrome (CMS) which are rare disorders of hereditary neuromuscular transmission (NMT) has to be differentiated because immunotherapy has no benefit in this group. Molecular genetic studies of these diseases helps to identify specific type of CMS which is important as other drugs like Fluoxetine, Quinidine are found to be effective in some. In infancy, all can manifest as floppy infant syndrome. The important key to diagnosis is by detailed electrophysiological studies including repetitive nerve stimulation at slow and high rates and its response to anticholinesterases and estimation of Acetyl choline receptor antibodies. Other causes of neuromuscular transmission defects viz. snake venom poisoning and that due to drugs are discussed. PMID:18716738

  8. Constraints on string networks with junctions

    NASA Astrophysics Data System (ADS)

    Copeland, E. J.; Kibble, T. W. B.; Steer, D. A.

    2007-03-01

    We consider the constraints on string networks with junctions in which the strings may all be different, as may be found, for example, in a network of (p,q) cosmic superstrings. We concentrate on three aspects of junction dynamics. First we consider the propagation of small-amplitude waves across a static three-string junction. Then, generalizing our earlier work, we determine the kinematic constraints on two colliding strings with different tensions. As before, the important conclusion is that strings do not always reconnect with a third string; they can pass straight through one another (or in the case of non-Abelian strings become stuck in an X configuration), the constraint depending on the angle at which the strings meet, on their relative velocity, and on the ratios of the string tensions. For example, if the two colliding strings have equal tensions, then for ultrarelativistic initial velocities they pass through one another. However, if their tensions are sufficiently different they can reconnect. Finally, we consider the global properties of junctions and strings in a network. Assuming that, in a network, the incoming waves at a junction are independently randomly distributed, we determine the root-mean-square (r.m.s.) velocities of strings and calculate the average speed at which a junction moves along each of the three strings from which it is formed. Our findings suggest that junction dynamics may be such as to preferentially remove the heavy strings from the network leaving a network of predominantly light strings. Furthermore the r.m.s. velocity of strings in a network with junctions is smaller than 1/2, the result for conventional Nambu-Goto strings without junctions in Minkowski space-time.

  9. Constraints on string networks with junctions

    SciTech Connect

    Copeland, E. J.; Kibble, T. W. B.; Steer, D. A.

    2007-03-15

    We consider the constraints on string networks with junctions in which the strings may all be different, as may be found, for example, in a network of (p,q) cosmic superstrings. We concentrate on three aspects of junction dynamics. First we consider the propagation of small-amplitude waves across a static three-string junction. Then, generalizing our earlier work, we determine the kinematic constraints on two colliding strings with different tensions. As before, the important conclusion is that strings do not always reconnect with a third string; they can pass straight through one another (or in the case of non-Abelian strings become stuck in an X configuration), the constraint depending on the angle at which the strings meet, on their relative velocity, and on the ratios of the string tensions. For example, if the two colliding strings have equal tensions, then for ultrarelativistic initial velocities they pass through one another. However, if their tensions are sufficiently different they can reconnect. Finally, we consider the global properties of junctions and strings in a network. Assuming that, in a network, the incoming waves at a junction are independently randomly distributed, we determine the root-mean-square (r.m.s.) velocities of strings and calculate the average speed at which a junction moves along each of the three strings from which it is formed. Our findings suggest that junction dynamics may be such as to preferentially remove the heavy strings from the network leaving a network of predominantly light strings. Furthermore the r.m.s. velocity of strings in a network with junctions is smaller than 1/{radical}(2), the result for conventional Nambu-Goto strings without junctions in Minkowski space-time.

  10. Ureteropelvic junction disease: diagnostic imaging.

    PubMed

    Maresca, Giulia; Maggi, Fabio; Valentini, Viola

    2002-01-01

    Ureteropelvic junction disease is very frequent in pediatric age. Diagnosis is usually established on sonography; in most cases it is prenatal and confirmed at birth. On sonography, hydronephrosis and the site of obstruction is identified with morphofunctional information on renal parenchyma. In the past, urography was the reference examination for ureteropelvic junction disease, but its use is limited in pediatrics especially in prenatal study for radioprotection as well as for the limited glomerular filtration of neonatal kidney. CT and MRI as second level examinations do not find many indications, while angioscintigraphy is largely used to acquire functional data and, in combination with sonography, is basic for diagnosis as well as in follow-up of operated patients. PMID:12696256

  11. Three-junction solar cell

    DOEpatents

    Ludowise, Michael J.

    1986-01-01

    A photovoltaic solar cell is formed in a monolithic semiconductor. The cell contains three junctions. In sequence from the light-entering face, the junctions have a high, a medium, and a low energy gap. The lower junctions are connected in series by one or more metallic members connecting the top of the lower junction through apertures to the bottom of the middle junction. The upper junction is connected in voltage opposition to the lower and middle junctions by second metallic electrodes deposited in holes 60 through the upper junction. The second electrodes are connected to an external terminal.

  12. [A case of dural arteriovenous fistula at the craniocervical junction, which spinal MRI findings reveals increased intensity signal in Th3-medullary cone].

    PubMed

    Ueda, Masamichi; Ueda, Miki; Takeuchi, Yuko; Ochiai, Jun; Mabuchi, Chiyuki; Hattori, Shinnosuke

    2016-01-01

    A 60-year-old woman had transient weakness of the legs and urinary retention for six weeks. She presented with a gait disorder and was admitted to the hospital. She showed symptoms of paraplegia, tingling in the lower extremities, dysuria. She underwent an MRI, and T2-weighted images showed an enlargement of the thoracolumbar spinal cord and high intensity signal from Th3 to the medullary cone, and a contrast-enhanced T1-weighted image showed abnormal vessels anterior to the spine cord. Cervical and spinal angiography documented a dural arteriovenous fistula at the craniocervical junction that was fed by the right vertebral artery and the right ascending pharyngeal arteries and drained into the perimedullary veins. Surgical therapy improved her symptoms and MRI images. Craniocervical junction DAVF with thoracic-medullary cones lesion is rare. PMID:26616488

  13. Notalgia paresthetica associated with cervical spinal stenosis and cervicothoracic disk disease at C4 through C7.

    PubMed

    Alai, Nili N; Skinner, Harry B; Nabili, Siamak T; Jeffes, Edward; Shahrokni, Seyed; Saemi, Arash M

    2010-02-01

    Notalgia paresthetica (NP) is a common refractory, sensory, neuropathic syndrome with the hallmark symptom of localized pruritus of the unilateral infrascapular back. It generally is a chronic noncurable condition with periodic remissions and exacerbations. While the dermatologic syndrome may be multifactorial in etiology, a possible association with underlying cervical spine disease should be evaluated for proper treatment. Collaborative multispecialty evaluation by dermatology, radiology, orthopedic surgery, and neurology may be indicated for primary management of this condition. First-line therapy for NP with associated cervical disease may include nondermatologic noninvasive treatments such as spinal manipulation, physical therapy, massage, cervical traction, cervical muscle strengthening, and oral nonsteroidal anti-inflammatory drugs and muscle relaxants. Notalgia paresthetica may in fact be a cutaneous sign of an underlying degenerative cervical spine disease. We report a case of a patient with cervical spinal stenosis that corresponded directly with the clinical findings of NP. PMID:20349681

  14. The 'depletion layer' of amorphous p-n junctions

    NASA Technical Reports Server (NTRS)

    Von Roos, O.

    1981-01-01

    It is shown that within reasonable approximations for the density of state distribution within the mobility gap of a:Si, a one-to-one correspondence exists between the electric field distribution in the transition region of an amorphous p-n junction and that in the depletion layer of a crystalline p-n junction. Thus it is inferred that the depletion layer approximation which leads to a parabolic potential distribution within the depletion layer of crystalline junctions also constitutes a fair approximation in the case of amorphous junctions. This fact greatly simplifies an analysis of solid-state electronic devices based on amorphous material (i.e., solar cells).

  15. Doped semiconductor nanocrystal junctions

    NASA Astrophysics Data System (ADS)

    Borowik, Ł.; Nguyen-Tran, T.; Roca i Cabarrocas, P.; Mélin, T.

    2013-11-01

    Semiconductor junctions are the basis of electronic and photovoltaic devices. Here, we investigate junctions formed from highly doped (ND≈1020-1021cm-3) silicon nanocrystals (NCs) in the 2-50 nm size range, using Kelvin probe force microscopy experiments with single charge sensitivity. We show that the charge transfer from doped NCs towards a two-dimensional layer experimentally follows a simple phenomenological law, corresponding to formation of an interface dipole linearly increasing with the NC diameter. This feature leads to analytically predictable junction properties down to quantum size regimes: NC depletion width independent of the NC size and varying as ND-1/3, and depleted charge linearly increasing with the NC diameter and varying as ND1/3. We thus establish a "nanocrystal counterpart" of conventional semiconductor planar junctions, here however valid in regimes of strong electrostatic and quantum confinements.

  16. Diencephalic-Mesencephalic Junction Dysplasia: A Novel Recessive Brain Malformation

    ERIC Educational Resources Information Center

    Zaki, Maha S.; Saleem, Sahar N.; Dobyns, William B.; Barkovich, A. James; Bartsch, Hauke; Dale, Anders M.; Ashtari, Manzar; Akizu, Naiara; Gleeson, Joseph G.; Grijalvo-Perez, Ana Maria

    2012-01-01

    We describe six cases from three unrelated consanguineous Egyptian families with a novel characteristic brain malformation at the level of the diencephalic-mesencephalic junction. Brain magnetic resonance imaging demonstrated a dysplasia of the diencephalic-mesencephalic junction with a characteristic "butterfly"-like contour of the midbrain on…

  17. Quantum junction solar cells.

    PubMed

    Tang, Jiang; Liu, Huan; Zhitomirsky, David; Hoogland, Sjoerd; Wang, Xihua; Furukawa, Melissa; Levina, Larissa; Sargent, Edward H

    2012-09-12

    Colloidal quantum dot solids combine convenient solution-processing with quantum size effect tuning, offering avenues to high-efficiency multijunction cells based on a single materials synthesis and processing platform. The highest-performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO(2)); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising the benefits of facile quantum tuning. Here we report rectifying junctions constructed entirely using inherently band-aligned quantum-tuned materials. Realizing these quantum junction diodes relied upon the creation of an n-type quantum dot solid having a clean bandgap. We combine stable, chemically compatible, high-performance n-type and p-type materials to create the first quantum junction solar cells. We present a family of photovoltaic devices having widely tuned bandgaps of 0.6-1.6 eV that excel where conventional quantum-to-bulk devices fail to perform. Devices having optimal single-junction bandgaps exhibit certified AM1.5 solar power conversion efficiencies of 5.4%. Control over doping in quantum solids, and the successful integration of these materials to form stable quantum junctions, offers a powerful new degree of freedom to colloidal quantum dot optoelectronics. PMID:22881834

  18. Iniencephaly: Case Report

    PubMed Central

    Alvis-Miranda, Hernando R.; Bula-Anichiarico, Doris A.; Calderón-Miranda, Willem G.; Moscote-Salazar, Luis R.

    2015-01-01

    The iniencephaly involves a variable defect in the occipital bone, resulting in a large foramen magnum, partial or total absence of the cervical and thoracic vertebrae, accompanied by incomplete closure of arcs and/or vertebral bodies, significant shortening of the spinal column and hyperextension of the malformed cervicothoracic spine; the individual's face is deviated upward, the mandibular skin is directly continuous with anterior thorax due to the absence of neck. Its incidence is about 1:1000–1:2000 births, so this is a pretty rare neural tube defect. We present a case of iniencephaly in association with cardiovascular, spinal cord, and intracranial malformations that ended demonstrating the low survival of patients affected with this condition. PMID:26167231

  19. Electrostatic model of radial pn junction nanowires

    NASA Astrophysics Data System (ADS)

    Chia, A. C. E.; LaPierre, R. R.

    2013-08-01

    Poisson's equation is solved for a radial pn junction nanowire (NW) with surface depletion. This resulted in a model capable of giving radial energy band and electric field profiles for any arbitrary core/shell doping density, core/shell dimensions, and surface state density. Specific cases were analyzed to extract pertinent underlying physics, while the relationship between NW specifications and the depletion of the NW were examined to optimize the built-in potential across the junction. Additionally, the model results were compared with experimental results in literature to good agreement. Finally, an optimum device design is proposed to satisfy material, optical, and electrostatic constraints in high efficiency NW solar cells.

  20. Josephson junctions with alternating critical current density

    SciTech Connect

    Mints, R.G.; Kogan, V.G.

    1997-04-01

    The magnetic-field dependence of the critical current I{sub c}(H) is considered for a short Josephson junction with the critical current density j{sub c} alternating along the tunnel contact. Two model cases, periodic and randomly alternating j{sub c}, are treated in detail. Recent experimental data on I{sub c}(H) for grain-boundary Josephson junctions in YBa{sub 2}Cu{sub 3}O{sub x} are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  1. Four-junction superconducting circuit

    NASA Astrophysics Data System (ADS)

    Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J. Q.

    2016-06-01

    We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit.

  2. Four-junction superconducting circuit.

    PubMed

    Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J Q

    2016-01-01

    We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit. PMID:27356619

  3. Four-junction superconducting circuit

    PubMed Central

    Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J. Q.

    2016-01-01

    We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit. PMID:27356619

  4. T-Junction Benchmark

    SciTech Connect

    2010-01-01

    Part 1: Two different volume renderings of fluid temperatures in a turbulent T-junction mixing problem at Reynolds number Re=40,000. Part 2: Volume rendering of fluid temperatures in a turbulent T-junction mixing problem at Reynolds number Re=40,000, simulated using Nek5000 at three different resolutions. Part 3: Temperature distribution for a turbulent T-junction mixing problem at Reynolds number Re=40,000, simulated using Nek5000 with 89056 spectral elements of order N=9 (65 million grid points). Credits: Science: Aleks Obabko and Paul Fisher, Argonne National Laboratory
 Visualization: Hank Childs, Lawrence Berkeley National Laboratory

 This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract DE-AC02-06CH11357

  5. Proximal Junctional Kyphosis: Diagnosis, Pathogenesis, and Treatment

    PubMed Central

    Lee, Jaewon

    2016-01-01

    Proximal junctional kyphosis (PJK) is a common radiographic finding after long spinal fusion. A number of studies on the causes, risk factors, prevention, and treatment of PJK have been conducted. However, no clear definition of PJK has been established. In this paper, we aimed to clarify the diagnosis, prevention, and treatment of PJK by reviewing relevant papers that have been published to date. A literature search was conducted on PubMed using "proximal junctional", "proximal junctional kyphosis", and "proximal junctional failure" as search keywords. Only studies that were published in English were included in this study. The incidence of PJK ranges from 5% to 46%, and it has been reported that 66% of cases occur 3 months after surgery and approximately 80% occur within 18 months. A number of studies have reported that there is no significantly different clinical outcome between PJK patients and non-PJK patients. One study showed that PJK patients expressed more pain than non-PJK patients. However, recent studies focused on proximal junctional failure (PJF), which is accepted as a severe form of PJK. PJF showed significant adverse impact in clinical aspect such as pain, neurologic deficit, ambulatory difficulties, and social isolation. Numerous previous studies have identified various risk factors and reported on the treatment and prevention of PJK. Based on these studies, we determined the clinical significance and impact of PJK. In addition, it is important to find a strategic approach to the proper treatment of PJK. PMID:27340542

  6. Steady-state currents in p-n junction filaments or grains in case of large surface recombination velocities at lateral surfaces

    NASA Technical Reports Server (NTRS)

    Von Roos, O.; Lindholm, F. A.

    1985-01-01

    Recently it has been pointed out that the saturation current of a semiconductor filament which constitutes part of a p-n junction diverges when the surface recombination velocity at the faces become infinitely large. Here it is pointed out that this is to be expected on physical grounds since, whenever the carrier concentration is kept off equilibrium by an outside agent, and at the same time recombination lifetimes in the bulk or in surface layers tend to zero, concentration gradients tend to infinity. As also previously noted, the situation can be remedied by using realistic (finite) surface recombination velocities in model calculations. However, this procedure leads to mathematical complexities which have been circumvented recently by the introduction of a heuristic approach. It is the aim of this paper to assess the validity of the heuristic approach by means of detailed and exact calculations.

  7. A fluid flow in the pipe junction with 6,25 cross-section area ratio. the influence of the adjacent branch angle on the pipe junction characteristics

    NASA Astrophysics Data System (ADS)

    Štigler, J.; Šperka, O.; Klas, R.

    2012-11-01

    This article deals with a fluid flow in the pipe junction. The comparison of the pipe junction characteristics obtained from the experiment with the pipe junction characteristics obtained from the numerical modelling using the CFD software will be discussed in this article. All measurements are done for the case of 50 mm diameter of the straight pipe and 20 mm diameter of the adjacent branch with five different angles. There are six possible flow configurations for this pipe junction. Three of them are cases of the flow combination and three of them are cases of the flow division. Only results for the flow combination are presented in this paper.

  8. Squeezable electron tunneling junctions

    NASA Astrophysics Data System (ADS)

    Moreland, J.; Alexander, S.; Cox, M.; Sonnenfeld, R.; Hansma, P. K.

    1983-09-01

    We report a versatile new technique for constructing electron tunneling junctions with mechanically-adjusted artificial barriers. I-V curves are presented for tunneling between Ag electrodes with vacuum, gas, liquid or solid in the barrier. An energy gap is apparent in the measured I-V curve when tunneling occurs between superconducting Pb electrodes.

  9. Doped semiconductor nanocrystal junctions

    SciTech Connect

    Borowik, Ł.; Mélin, T.; Nguyen-Tran, T.; Roca i Cabarrocas, P.

    2013-11-28

    Semiconductor junctions are the basis of electronic and photovoltaic devices. Here, we investigate junctions formed from highly doped (N{sub D}≈10{sup 20}−10{sup 21}cm{sup −3}) silicon nanocrystals (NCs) in the 2–50 nm size range, using Kelvin probe force microscopy experiments with single charge sensitivity. We show that the charge transfer from doped NCs towards a two-dimensional layer experimentally follows a simple phenomenological law, corresponding to formation of an interface dipole linearly increasing with the NC diameter. This feature leads to analytically predictable junction properties down to quantum size regimes: NC depletion width independent of the NC size and varying as N{sub D}{sup −1/3}, and depleted charge linearly increasing with the NC diameter and varying as N{sub D}{sup 1/3}. We thus establish a “nanocrystal counterpart” of conventional semiconductor planar junctions, here however valid in regimes of strong electrostatic and quantum confinements.

  10. Victory Junction Gang Camp

    ERIC Educational Resources Information Center

    Shell, Ryan

    2007-01-01

    This article describes the Victory Junction Gang Camp, a not-for-profit, NASCAR-themed camp for children with chronic medical conditions that serves 24 different disease groups. The mission of the camp is to give children life-changing camping experiences that are exciting, fun, and empowering in a safe and medically sound environment. While doing…

  11. Josephson junction mixing.

    NASA Technical Reports Server (NTRS)

    Thompson, E. D.

    1973-01-01

    A theory is presented which, though too simple to explain quantitative details in the Josephson junction mixing response, is sufficient for explaining qualitatively the results observed. Crucial to the theory presented, and that which differentiates it from earlier ones, is the inclusion of harmonic voltages across the ideal Josephson element.

  12. Brain barriers: Crosstalk between complex tight junctions and adherens junctions

    PubMed Central

    Tietz, Silvia

    2015-01-01

    Unique intercellular junctional complexes between the central nervous system (CNS) microvascular endothelial cells and the choroid plexus epithelial cells form the endothelial blood–brain barrier (BBB) and the epithelial blood–cerebrospinal fluid barrier (BCSFB), respectively. These barriers inhibit paracellular diffusion, thereby protecting the CNS from fluctuations in the blood. Studies of brain barrier integrity during development, normal physiology, and disease have focused on BBB and BCSFB tight junctions but not the corresponding endothelial and epithelial adherens junctions. The crosstalk between adherens junctions and tight junctions in maintaining barrier integrity is an understudied area that may represent a promising target for influencing brain barrier function. PMID:26008742

  13. Magic-T Junction using Microstrip/Slotline Transitions

    NASA Technical Reports Server (NTRS)

    U-yen, Kongpop; Wollack, Edward J.; Doiron, Terence

    2008-01-01

    An improved broadband planar magic-T junction that incorporates microstrip/slotline transitions has been developed. In comparison with a prior broadband magic-T junction incorporating microstrip/slotline transitions, this junction offers superior broadband performance. In addition, because this junction is geometrically simpler and its performance is less affected by fabrication tolerances, the benefits of the improved design can be realized at lower fabrication cost. There are potential uses for junctions like this one in commercial microwave communication receivers, radar and polarimeter systems, and industrial microwave instrumentation. A magic-T junction is a four-port waveguide junction consisting of a combination of an H-type and an E-type junction. An E-type junction is so named because it includes a junction arm that extends from a main waveguide in the same direction as that of the electric (E) field in the waveguide. An H-type junction is so named because it includes a junction arm parallel to the magnetic (H) field in a main waveguide. A magic-T junction includes two input ports (here labeled 1 and 2, respectively) and two output ports (here labeled E and H, respectively). In an ideal case, (1) a magic-T junction is lossless, (2) the input signals add (that is, they combine in phase with each other) at port H, and (3) the input signals subtract (that is, they combine in opposite phase) at port E. The prior junction over which the present junction is an improvement affords in-phase-combining characterized by a broadband frequency response, and features a small slotline area to minimize in-band loss. However, with respect to isolation between ports 1 and 2 and return loss at port E, it exhibits narrowband frequency responses. In addition, its performance is sensitive to misalignment of microstrip and slotline components: this sensitivity is attributable to a limited number of quarter-wavelength (lambda/4) transmission-line sections for matching impedances

  14. Simultaneous percutaneous nephrolithotomy and early endoscopic ureteric realignment for iatrogenic ureteropelvic junction avulsion during ureteroscopy

    PubMed Central

    Tayeb, Marawan El; Mellon, Matthew J.; Lingeman, James E.

    2015-01-01

    We present a case report of successful management of ureteropelvice junction avulsion during ureteroscopy successfully managed with simultaneous percutaneous nephrolithotomy and early endoscopic ureteral realignment. PMID:26834898

  15. Precordial junctional ST-segment depression with tall symmetric T-waves signifying proximal LAD occlusion, case reports of STEMI equivalence.

    PubMed

    de Winter, Ruben W; Adams, Rob; Verouden, Niels J W; de Winter, Robbert J

    2016-01-01

    Timely reperfusion therapy by means of primary percutaneous coronary intervention (PCI) is the preferred treatment for patients with ST-segment elevation myocardial infarction. A significant number of patients with large acute myocardial infarction, caused by occlusion of an epicardial coronary artery, do not show ST-elevation on the electrocardiogram. Other ECG abnormalities may be present, the so called STEMI-equivalents. One such STEMI equivalent, junctional ST-segment depression followed by tall symmetrical T-waves in the precordial leads, often in combination with slight ST-elevation in lead AVR, has been associated with proximal occlusion of the left anterior descending coronary artery. Recognition of this ECG pattern by ambulance staff, emergency physicians and interventional cardiologists envolved in STEMI networks, is important to ensure timely reperfusion therapy in these patients. In this paper we present three patients with typical symptoms of acute myocardial infarction and the ECG pattern with slight J-point depression combined with tall, symmetrical T-waves. PMID:26560436

  16. Holliday Junction Resolvases

    PubMed Central

    Wyatt, Haley D.M.; West, Stephen C.

    2014-01-01

    Four-way DNA intermediates, called Holliday junctions (HJs), can form during meiotic and mitotic recombination, and their removal is crucial for chromosome segregation. A group of ubiquitous and highly specialized structure-selective endonucleases catalyze the cleavage of HJs into two disconnected DNA duplexes in a reaction called HJ resolution. These enzymes, called HJ resolvases, have been identified in bacteria and their bacteriophages, archaea, and eukaryotes. In this review, we discuss fundamental aspects of the HJ structure and their interaction with junction-resolving enzymes. This is followed by a brief discussion of the eubacterial RuvABC enzymes, which provide the paradigm for HJ resolvases in other organisms. Finally, we review the biochemical and structural properties of some well-characterized resolvases from archaea, bacteriophage, and eukaryotes. PMID:25183833

  17. Wireless Josephson Junction Arrays

    NASA Astrophysics Data System (ADS)

    Adams, Laura

    2015-03-01

    We report low temperature, microwave transmission measurements on a wireless two- dimensional network of Josephson junction arrays composed of superconductor-insulator -superconductor tunnel junctions. Unlike their biased counterparts, by removing all electrical contacts to the arrays and superfluous microwave components and interconnects in the transmission line, we observe new collective behavior in the transmission spectra. In particular we will show emergent behavior that systematically responds to changes in microwave power at fixed temperature. Likewise we will show the dynamic and collective response of the arrays while tuning the temperature at fixed microwave power. We discuss these spectra in terms of the Berezinskii-Kosterlitz-Thouless phase transition and Shapiro steps. We gratefully acknowledge the support Prof. Steven Anlage at the University of Maryland and Prof. Allen Goldman at the University of Minnesota. Physics and School of Engineering and Applied Sciences.

  18. Antireflection Coating Design for Series Interconnected Multi-Junction Solar Cells

    SciTech Connect

    AIKEN,DANIEL J.

    1999-11-29

    AR coating design for multi-junction solar cells can be more challenging than in the single junction case. Reasons for this are discussed. Analytical expressions used to optimize AR coatings for single junction solar cells are extended for use in monolithic, series interconnected multi-junction solar cell AR coating design. The result is an analytical expression which relates the solar cell performance (through J{sub SC}) directly to the AR coating design through the device reflectance. It is also illustrated how AR coating design can be used to provide an additional degree of freedom for current matching multi-junction devices.

  19. Thermoelectricity in molecular junctions.

    PubMed

    Reddy, Pramod; Jang, Sung-Yeon; Segalman, Rachel A; Majumdar, Arun

    2007-03-16

    By trapping molecules between two gold electrodes with a temperature difference across them, the junction Seebeck coefficients of 1,4-benzenedithiol (BDT), 4,4'-dibenzenedithiol, and 4,4''-tribenzenedithiol in contact with gold were measured at room temperature to be +8.7 +/- 2.1 microvolts per kelvin (muV/K), +12.9 +/- 2.2 muV/K, and +14.2 +/- 3.2 muV/K, respectively (where the error is the full width half maximum of the statistical distributions). The positive sign unambiguously indicates p-type (hole) conduction in these heterojunctions, whereas the Au Fermi level position for Au-BDT-Au junctions was identified to be 1.2 eV above the highest occupied molecular orbital level of BDT. The ability to study thermoelectricity in molecular junctions provides the opportunity to address these fundamental unanswered questions about their electronic structure and to begin exploring molecular thermoelectric energy conversion. PMID:17303718

  20. Nonlinear microwave absorption in weak-link Josephson junctions

    SciTech Connect

    Xie, L.M.; Wosik, J.; Wolfe, J.C.

    1996-12-01

    A model, based on the resistively shunted junction theory, is developed and used to study microwave absorption in weak-link Josephson junctions in high-{ital T}{sub {ital c}} superconductors. Both linear and nonlinear cases of microwave absorption in Josephson junctions are analyzed. A comparison of the model with microwave absorption loop theory is presented along with a general condition for the applicability of both models. The nonlinear case was solved numerically and the threshold points of sharp microwave absorption are presented. At these points, a 2{pi} phase quantization takes place within each microwave cycle, leading to an onset of a sharp rise of absorption. Existence of the 2{pi} dynamic quantization is the key to the interpretation of nonlinear microwave absorption data. The nonlinear microwave absorption model is extended to the study of nonuniformly coupled junctions, and a general statement for the applicability of such a model is presented. {copyright} {ital 1996 The American Physical Society.}

  1. Suppression of Andreev conductance in a topological insulator-superconductor nanostep junction

    NASA Astrophysics Data System (ADS)

    Yi-Jie, Zheng; Jun-Tao, Song; Yu-Xian, Li

    2016-03-01

    When two three-dimensional topological insulators (TIs) are brought close to each other with their surfaces aligned, the surfaces form a line junction. Similarly, three TI surfaces, not lying in a single plane, can form an atomic-scale nanostep junction. In this paper, Andreev reflection in a TI-TI-superconductor nanostep junction is investigated theoretically. Because of the existence of edge states along each line junction, the conductance for a nanostep junction is suppressed. When the incident energy (ɛ) of an electron is larger than the superconductor gap (Δ), the Andreev conductance in a step junction is less than unity while for a plane junction it is unity. The Andreev conductance is found to depend on the height of the step junction. The Andreev conductance exhibits oscillatory behavior as a function of the junction height with the amplitude of the oscillations remaining unchanged when ɛ = 0, but decreasing for ɛ = Δ, which is different from the case of the plane junction. The height of the step is therefore an important parameter for Andreev reflection in nanostep junctions, and plays a role similar to that of the delta potential barrier in normal metal-superconductor plane junctions. Project supported by the National Natural Science Foundation of China (Grant Nos. 11204065 and 11474085) and the Natural Science Foundation of Hebei Province, China (Grant Nos. A2013205168 and A2014205005).

  2. Successful treatment of a ruptured aneurysm at the vertebral artery-posterior inferior cerebellar artery junction and simultaneous treatment of the stenotic vertebral artery with a single flow-diverting stent: a case report

    PubMed Central

    2014-01-01

    Introduction This is the first report on the simultaneous successful treatment of a large ruptured saccular aneurysm and stenotic parent artery with a single flow-diverting stent. Case presentation We report the case of a 68-year-old Caucasian man with occlusion of the right vertebral artery and a ruptured aneurysm at the junction of the left posterior inferior cerebellar artery-left vertebral artery that was successfully treated by the deployment of a single flow-diverting stent in the stenotic left vertebral artery. Stent deployment was complicated by thrombotic occlusion of the basilar artery, which was successfully reopened. The patient recovered completely, and follow-up angiography at 4 months and 1 year showed patent vertebral artery with gradual shrinkage of the aneurysm. Conclusions This report contributes to the literature on treatment of large ruptured aneurysms localized in stenotic arteries and in areas of the endocranium where a mass of embolic material in the aneurysm (coils) might compromise the circulation in the parent blood vessel or compress vital brain structures. PMID:24886040

  3. An unusual cause of chronic abdominal pain after laparoscopic Roux en Y gastric bypass: Case report of a penetrating fish bone causing adhesions at the biliary-digestive junction resulting in partial obstruction and chronic symptoms

    PubMed Central

    Ochieng, Vincent; Hendrickx, Leo; Valk, Jody

    2016-01-01

    Background The management of chronic abdominal pain after laparoscopic Roux-en-Y gastric bypass (LRYGP) is complex and challenging. Foreign body intestinal perforation including that caused by fish bones has previously been reported in the literature and if clinically unrecognized, can cause significant morbidity and mortality. Fish bone perforation as a cause of chronic abdominal pain after LRYGP has rarely been reported. Summary The unusual case of a 54 year old female presenting with recurrent episodes of postprandial pain 2 years after LRYGP is reported. Previous radiological and endoscopic investigations did not reveal any abnormality and after the most recent clinical presentation, a laparoscopic exploration was performed. A protruding fish bone at the biliary-digestive junction was discovered intra-operatively and successfully extracted. Dense adhesions between the involved intestinal loops were lysed in an attempt to improve intestinal transit and subsequently relieve post-prandial pain. Conclusion This case highlights the possibility of a missed fish bone perforation causing chronic postprandial abdominal pain and discomfort in a patient with a Roux-en-Y gastric bypass anatomy. Foreign body perforation is a rare cause of abdominal pain after gastric bypass that should be considered when evaluating chronic abdominal pain symptoms after LRYGP. PMID:27107305

  4. A rare presentation of lipoma on mandibular mucogingival junction

    PubMed Central

    Sharma, Gaurav; Jain, Kanu; Nagpal, Archna; Baiju, Chandrababu Sudha

    2016-01-01

    Lipoma is the most common tumor of mesenchymal tissues of body, but its occurrence in oral cavity is infrequent. Buccal mucosa is the most common intraoral site of lipoma followed by tongue, floor of the mouth, and buccal vestibule. The involvement of mucogingival junction is rare. We present a unique case report of oral lipoma occurring on mandibular mucogingival junction with review of literature which has emphasis on differential diagnosis. PMID:27143835

  5. Quantum statistical theory of semiconductor junctions in thermal equilibrium

    NASA Technical Reports Server (NTRS)

    Von Roos, O.

    1977-01-01

    Free carrier and electric field distributions of one-dimensional semiconductor junctions are evaluated using a quantum mechanical phase-space distribution and its corresponding Boltzmann equation. Attention is given to quantum and exchange corrections in cases of high doping concentrations when carrier densities become degenerate. Quantitative differences between degenerate and classical junction characteristics, e.g., maximum electric field and built-in voltage and carrier concentration within the transition region, are evaluated numerically.

  6. A rare presentation of lipoma on mandibular mucogingival junction.

    PubMed

    Sharma, Gaurav; Jain, Kanu; Nagpal, Archna; Baiju, Chandrababu Sudha

    2016-01-01

    Lipoma is the most common tumor of mesenchymal tissues of body, but its occurrence in oral cavity is infrequent. Buccal mucosa is the most common intraoral site of lipoma followed by tongue, floor of the mouth, and buccal vestibule. The involvement of mucogingival junction is rare. We present a unique case report of oral lipoma occurring on mandibular mucogingival junction with review of literature which has emphasis on differential diagnosis. PMID:27143835

  7. Gravitational radiation by cosmic strings in a junction

    SciTech Connect

    Brandenberger, R.; Karouby, J.; Firouzjahi, H.; Khosravi, S.

    2009-01-15

    The formalism for computing the gravitational power radiation from excitations on cosmic strings forming a junction is presented and applied to the simple case of co-planar strings at a junction when the excitations are generated along one string leg. The effects of polarization of the excitations and of the back-reaction of the gravitational radiation on the small scale structure of the strings are studied.

  8. Signatures of topological Josephson junctions

    NASA Astrophysics Data System (ADS)

    Peng, Yang; Pientka, Falko; Berg, Erez; Oreg, Yuval; von Oppen, Felix

    2016-08-01

    Quasiparticle poisoning and diabatic transitions may significantly narrow the window for the experimental observation of the 4 π -periodic dc Josephson effect predicted for topological Josephson junctions. Here, we show that switching-current measurements provide accessible and robust signatures for topological superconductivity which persist in the presence of quasiparticle poisoning processes. Such measurements provide access to the phase-dependent subgap spectrum and Josephson currents of the topological junction when incorporating it into an asymmetric SQUID together with a conventional Josephson junction with large critical current. We also argue that pump-probe experiments with multiple current pulses can be used to measure the quasiparticle poisoning rates of the topological junction. The proposed signatures are particularly robust, even in the presence of Zeeman fields and spin-orbit coupling, when focusing on short Josephson junctions. Finally, we also consider microwave excitations of short topological Josephson junctions which may complement switching-current measurements.

  9. [Gap junction and diabetic foot].

    PubMed

    Zou, Xiao-rong; Tao, Jian; Wang, Yun-kai

    2015-11-01

    Gap junctions play a critical role in electrical synchronization and exchange of small molecules between neighboring cells; connexins are a family of structurally related transmembrane proteins that assemble to form vertebrate gap junctions. Hyperglycemia changes the structure gap junction proteins and their expression, resulting in obstruction of neural regeneration, vascular function and wound healing, and also promoting vascular atherosclerosis. These pathogenic factors would cause diabetic foot ulcers. This article reviews the involvement of connexins in pathogenesis of diabetic foot. PMID:26822053

  10. Josephson junction simulation of neurons

    NASA Astrophysics Data System (ADS)

    Crotty, Patrick; Schult, Dan; Segall, Ken

    2010-07-01

    With the goal of understanding the intricate behavior and dynamics of collections of neurons, we present superconducting circuits containing Josephson junctions that model biologically realistic neurons. These “Josephson junction neurons” reproduce many characteristic behaviors of biological neurons such as action potentials, refractory periods, and firing thresholds. They can be coupled together in ways that mimic electrical and chemical synapses. Using existing fabrication technologies, large interconnected networks of Josephson junction neurons would operate fully in parallel. They would be orders of magnitude faster than both traditional computer simulations and biological neural networks. Josephson junction neurons provide a new tool for exploring long-term large-scale dynamics for networks of neurons.

  11. An induced junction photovoltaic cell

    NASA Technical Reports Server (NTRS)

    Call, R. L.

    1974-01-01

    Silicon solar cells operating with induced junctions rather than diffused junctions have been fabricated and tested. Induced junctions were created by forming an inversion layer near the surface of the silicon by supplying a sheet of positive charge above the surface. Measurements of the response of the inversion layer cell to light of different wavelengths indicated it to be more sensitive to the shorter wavelengths of the sun's spectrum than conventional cells. The greater sensitivity occurs because of the shallow junction and the strong electric field at the surface.

  12. Hormonal regulation of hepatocyte tight junctional permeability

    SciTech Connect

    Lowe, P.J.; Miyai, K.; Steinbach, J.H.; Hardison, W.G.M. Univ. of California, San Diego )

    1988-10-01

    The authors have investigated the effects of hormones on the permeability of the hepatocyte tight junction to two probes, ({sup 14}C)sucrose and horseradish peroxidase, using one-pass perfused rat livers. Using a single injection of horseradish peroxidase the authors have demonstrated that this probe can enter bile by two pathways that are kinetically distinct, a fast pathway, which corresponds to the passage of the probe through the hepatocyte tight junctions, and a slow pathway, which corresponds to the transcytotic entry into bile. The passage of horseradish peroxidase through the hepatocyte tight junctions was confirmed by electron microscopic histochemistry. Vasopressin, epinephrine, and angiotensin II, hormones that act in the hepatocyte through the intracellular mediators calcium, the inositol polyphosphates, and diacylglycerol, increased the bile-to-perfusion fluid ratio of ({sup 14}C)sucrose and the rapid entry of horseradish peroxidase into bile, indicating that the permeability of the tight junctions to these probes was increased. The effect of these hormones was dose dependent and in the cases of angiotensin II and epinephrine was inhibited by the specific inhibitors (Sar{sup 1},Thr{sup 8})angiotensin II and prazosin, respectively. Dibutyryl adenosine 3{prime},5{prime}-cyclic monophosphate did not affect the ({sup 14}C)sucrose bile-to-perfusion fluid ratio or the fast entry of horseradish peroxidase into bile. These results suggest that the hepatocyte tight junction can no longer be considered a static system of pores separating blood from bile. It is rather a dynamic barrier potentially capable of influencing the composition of the bile.

  13. GUARD RING SEMICONDUCTOR JUNCTION

    DOEpatents

    Goulding, F.S.; Hansen, W.L.

    1963-12-01

    A semiconductor diode having a very low noise characteristic when used under reverse bias is described. Surface leakage currents, which in conventional diodes greatly contribute to noise, are prevented from mixing with the desired signal currents. A p-n junction is formed with a thin layer of heavily doped semiconductor material disposed on a lightly doped, physically thick base material. An annular groove cuts through the thin layer and into the base for a short distance, dividing the thin layer into a peripheral guard ring that encircles the central region. Noise signal currents are shunted through the guard ring, leaving the central region free from such currents. (AEC)

  14. Tight Junctions Go Viral!

    PubMed Central

    Torres-Flores, Jesús M.; Arias, Carlos F.

    2015-01-01

    Tight junctions (TJs) are highly specialized membrane domains involved in many important cellular processes such as the regulation of the passage of ions and macromolecules across the paracellular space and the establishment of cell polarity in epithelial cells. Over the past few years there has been increasing evidence that different components of the TJs can be hijacked by viruses in order to complete their infectious cycle. Viruses from at least nine different families of DNA and RNA viruses have been reported to use TJ proteins in their benefit. For example, TJ proteins such as JAM-A or some members of the claudin family of proteins are used by members of the Reoviridae family and hepatitis C virus as receptors or co-receptors during their entry into their host cells. Reovirus, in addition, takes advantage of the TJ protein Junction Adhesion Molecule-A (JAM-A) to achieve its hematogenous dissemination. Some other viruses are capable of regulating the expression or the localization of TJ proteins to induce cell transformation or to improve the efficiency of their exit process. This review encompasses the importance of TJs for viral entry, replication, dissemination, and egress, and makes a clear statement of the importance of studying these proteins to gain a better understanding of the replication strategies used by viruses that infect epithelial and/or endothelial cells. PMID:26404354

  15. Neuromuscular junction disorders.

    PubMed

    Verschuuren, Jan; Strijbos, Ellen; Vincent, Angela

    2016-01-01

    Diseases of the neuromuscular junction comprise a wide range of disorders. Antibodies, genetic mutations, specific drugs or toxins interfere with the number or function of one of the essential proteins that control signaling between the presynaptic nerve ending and the postsynaptic muscle membrane. Acquired autoimmune disorders of the neuromuscular junction are the most common and are described here. In myasthenia gravis, antibodies to acetylcholine receptors or to proteins involved in receptor clustering, particularly muscle-specific kinase, cause direct loss of acetylcholine receptors or interfere with the agrin-induced acetylcholine receptor clustering necessary for efficient neurotransmission. In the Lambert-Eaton myasthenic syndrome (LEMS), loss of the presynaptic voltage-gated calcium channels results in reduced release of the acetylcholine transmitter. The conditions are generally recognizable clinically and the diagnosis confirmed by serologic testing and electromyography. Screening for thymomas in myasthenia or small cell cancer in LEMS is important. Fortunately, a wide range of symptomatic treatments, immunosuppressive drugs, or other immunomodulating therapies is available. Future research is directed to understanding the pathogenesis, discovering new antigens, and trying to develop disease-specific treatments. PMID:27112691

  16. The influence of the instabilities in modelling arteriovenous junction haemodynamics.

    PubMed

    Broderick, Stephen P; Houston, J Graeme; Walsh, Michael T

    2015-10-15

    The arteriovenous junction is characterised by high flow rates, large pressure difference and typically a palpable thrill or audible bruit, associated with turbulent flow. However, the arteriovenous junction is frequently studied with the assumption of streamline flow. This assumption is based on the Reynolds number calculation, although other factors can contribute to turbulent generation. In this study, the presence of instabilities is examined and the influencing factors discussed. This was performed using a pseudo-realistic geometry with adapted graft angles, vein diameter, outflow split ratio and graft inlet velocity values. Correlation was performed between steady and unsteady averaged simulation cases with correlation performance ranked. Overall the arteriovenous junction is capable of possessing highly disturbed flows, in which strict modelling requirements are necessary to capture such instabilities and avoid erroneous conclusions. Vein diameter and flow split ratio contribute to turbulent generation, thus Reynolds number cannot be used as a sole turbulent criterion in the arteriovenous junction. PMID:26315920

  17. Effects of the environment on the switching current in graphene-based Josephson Junctions

    NASA Astrophysics Data System (ADS)

    Borzenets, Ivan; Ke, Chung-Ting; Amet, Francois; Tso Wei, Ming; Yamamoto, Michihisa; Bomze, Yuriy; Tarucha, Seigo; Finkelstein, Gleb

    The nature of the switching current and hysteresis (difference between switching and retrapping currents) in graphene-based Josephson junctions depends greatly on the interaction with the environment. Conventional devices result in underdamped Josephson junctions making the true critical current inaccessible. On the other hand, heavily isolating the Josephson junctions places them in the microscopic quantum tunneling regime even at high temperatures, also masking the critical current. We study the critical current, and the switching statistics in graphene Josephson junctions while varying the effects of the environment. Proper isolation of graphene Josephson junctions is necessary to measure the true critical current, especially so for the cases of small currents around the Dirac point. This is true for the case of conventional diffusive as well as the novel ballistic Josephson junctions.

  18. Triple junctions and multi-directional extension of the lithosphere

    NASA Astrophysics Data System (ADS)

    Gerya, Taras; Burov, Evgenii

    2016-04-01

    new oceanic crust and lithosphere accretion. We document initial formation and destabilization of quadruple R-R-R-R junctions as initial plate rifting structures under bi-directional extension. In most cases, quadruple plate rifting junctions rapidly (typically within 1-2 Myr) evolve towards formation of two diverging triple oceanic spreading junctions connected by a linear spreading center lengthening with time. Asymmetric stretching results in various configurations, for example formation of "T-junctions" with trans-extensional components and combination of fast and slow spreading ridges. Numerical experiments also suggest that several existing oceanic spreading junctions form as the result of plate motions rearrangements after which only one of two plates spreading along the ridge becomes subjected to bi-directional spreading. Combined with plume impingement, this scenario evolves in realistic patterns closely resembling observed plate dynamics. In particular, opening of the Red Sea and of the Afar rift system find a logical explanation within a single model. We also demonstrate that the development of triple junctions should be an intrinsic feature of subduction and plate tectonics initiation triggered by plume-lithosphere interactions.

  19. Herlitz junctional epidermolysis bullosa.

    PubMed

    Laimer, Martin; Lanschuetzer, Christoph M; Diem, Anja; Bauer, Johann W

    2010-01-01

    Junctional epidermolysis bullosa type Herlitz (JEB-H) is the autosomal recessively inherited, more severe variant of "lucidolytic" JEB. Characterized by generalized, extensive mucocutaneous blistering at birth and early lethality, this devastating condition is most often caused by homozygous null mutations in the genes LAMA3, LAMB3, or LAMC2, each encoding for 1 of the 3 chains of the heterotrimer laminin-332. The JEB-H subtype usually presents as a severe and clinically diverse variant of the EB group of mechanobullous genodermatoses. This article outlines the epidemiology, presentation, and diagnosis of JEB-H. Morbidity and mortality are high, necessitating optimized protocols for early (including prenatal) diagnosis and palliative care. Gene therapy remains the most promising perspective. PMID:19945616

  20. Ion bipolar junction transistors.

    PubMed

    Tybrandt, Klas; Larsson, Karin C; Richter-Dahlfors, Agneta; Berggren, Magnus

    2010-06-01

    Dynamic control of chemical microenvironments is essential for continued development in numerous fields of life sciences. Such control could be achieved with active chemical circuits for delivery of ions and biomolecules. As the basis for such circuitry, we report a solid-state ion bipolar junction transistor (IBJT) based on conducting polymers and thin films of anion- and cation-selective membranes. The IBJT is the ionic analogue to the conventional semiconductor BJT and is manufactured using standard microfabrication techniques. Transistor characteristics along with a model describing the principle of operation, in which an anionic base current amplifies a cationic collector current, are presented. By employing the IBJT as a bioelectronic circuit element for delivery of the neurotransmitter acetylcholine, its efficacy in modulating neuronal cell signaling is demonstrated. PMID:20479274

  1. Ion bipolar junction transistors

    PubMed Central

    Tybrandt, Klas; Larsson, Karin C.; Richter-Dahlfors, Agneta; Berggren, Magnus

    2010-01-01

    Dynamic control of chemical microenvironments is essential for continued development in numerous fields of life sciences. Such control could be achieved with active chemical circuits for delivery of ions and biomolecules. As the basis for such circuitry, we report a solid-state ion bipolar junction transistor (IBJT) based on conducting polymers and thin films of anion- and cation-selective membranes. The IBJT is the ionic analogue to the conventional semiconductor BJT and is manufactured using standard microfabrication techniques. Transistor characteristics along with a model describing the principle of operation, in which an anionic base current amplifies a cationic collector current, are presented. By employing the IBJT as a bioelectronic circuit element for delivery of the neurotransmitter acetylcholine, its efficacy in modulating neuronal cell signaling is demonstrated. PMID:20479274

  2. ASSEMBLY AND CHARACTERIZATION OF 8-ARM AND 12-ARM DNA BRANCHED JUNCTIONS

    PubMed Central

    Wang, Xing

    2012-01-01

    Branched DNA molecules can be assembled into objects and networks directed by sticky-ended cohesion. The connectivity of these species is limited by the number of arms flanking the branch point. To date, the only branched junctions constructed contain six or fewer arms. We report the construction of DNA branched junctions that contain either 8 or 12 double helical arms surrounding a branch point. The design of the 8-arm junction expoits the limits of a previous approach to thwart branch migration, but the design of the 12-arm junction uses a new to principle achieve this end. The 8-arm junction is stable with 16 nucleotide pairs per arm, but the 12-arm junction has been stabilized by 24 nucleotide pairs per arm. Ferguson analysis of these junctions in combination with three, four, five, and six-arm junctions indicates a linear increase in friction constant as the number of arms increases; the four-arm junction migrates anomalously at 4°C., suggesting stacking of its domains. All strands in both the 8-arm and 12-arm junctions show similar responses to hydroxyl radical autofootprinting analysis, indicating that they lack any dominant stacking structures. The stability of the 12-arm junction demonstrates that the number of arms in a junction is not limited to the case of having adjacent identical base pairs flanking the junction. The ability to construct eight-arm and twelve-arm junctions increases the number of objects, graphs and networks that can be built from branched DNA components. In principle, the stick structure corresponding to cubic close packing is now a possible target for assembly by DNA nanotechnology. PMID:17564446

  3. Functional analysis of tight junction organization.

    PubMed

    DiBona, D R

    1985-01-01

    The functional basis of tight junction design has been examined from the point of view that this rate-limiting barrier to paracellular transport is a multicompartment system. Review of the osmotic sensitivity of these structures points to the need for this sort of analysis for meaningful correlation of structure and function under a range of conditions. A similar conclusion is drawn with respect to results from voltage-clamping protocols where reversal of spontaneous transmural potential difference elicits parallel changes in both structure and function in much the same way as does reversal of naturally occurring osmotic gradients. In each case, it becomes necessary to regard the junction as a functionally polarized structure to account for observations of its rectifying properties. Lastly, the details of experimentally-induced junction deformation are examined in light of current theories of its organization; arguments are presented in favor of the view that the primary components of intramembranous organization (as viewed with freeze-fracture techniques) are lipidic rather than proteinaceous. PMID:4088839

  4. Josephson junction in a thin film

    SciTech Connect

    Kogan, V. G.; Dobrovitski, V. V.; Clem, J. R.; Mawatari, Yasunori; Mints, R. G.

    2001-04-01

    The phase difference {phi}(y) for a vortex at a line Josephson junction in a thin film attenuates at large distances as a power law, unlike the case of a bulk junction where it approaches exponentially the constant values at infinities. The field of a Josephson vortex is a superposition of fields of standard Pearl vortices distributed along the junction with the line density {phi}'(y)/2{pi}. We study the integral equation for {phi}(y) and show that the phase is sensitive to the ratio l/{Lambda}, where l={lambda}{sub J}{sup 2}/{lambda}{sub L}, {Lambda}=2{lambda}{sub L}{sup 2}/d, {lambda}{sub L}, and {lambda}{sub J} are the London and Josephson penetration depths, and d is the film thickness. For l<<{Lambda}, the vortex ''core'' of the size l is nearly temperature independent, while the phase ''tail'' scales as l{Lambda}/y{sup 2}={lambda}{sub J}2{lambda}{sub L}/d/y{sup 2}; i.e., it diverges as T{yields}T{sub c}. For l>>{Lambda}, both the core and the tail have nearly the same characteristic length l{Lambda}.

  5. Fermi edge singularity in a tunnel junction

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Sherkunov, Yury; D'Ambrumenil, Nicholas; Muzykantskii, Boris

    2010-03-01

    We present results on the non-equilibrium Fermi edge singularity (FES) problem in tunnel junctions. The FES, which is present in a Fermi gas subject to any sudden change of potential, manifests itself in the final state many body interaction between the electrons in the leads [1]. We establish a connection between the FES problem in a tunnel junction and the Full Counting Statistics (FCS) for the device [2]. We find that the exact profile of the changing potential (or the profile for the barrier opening and closing in the tunnel junction case) strongly affects the overlap between the initial and final state of the Fermi gas. We factorize the contribution to the FES into two approximately independent terms: one is connected with the short time opening process while the other is concerned with the long time asymptotic effect, namely the Anderson orthogonality catastrophe. We consider applications to a localized level coupled through a tunnel barrier to a 1D lead driven out of equilibrium [3]. References: [1] G. Mahan, Phys. Rev. 163, 1612 (1967); P. Nozieres and C. T. De Dominicis, Phys. Rev. 178, 1079 (1969); P. Anderson, Phys. Rev. Lett. 18, 1049 (1967) [2] J. Zhang, Y. Sherkunov, N. d'Ambrumenil, and B. Muzykantskii, ArXiv:0909.3427 [3] D. Abanin and L. Levitov, Phys. Rev. Lett. 94, 186803 (2005)

  6. Thermopower measurements in molecular junctions.

    PubMed

    Rincón-García, Laura; Evangeli, Charalambos; Rubio-Bollinger, Gabino; Agraït, Nicolás

    2016-08-01

    The measurement of thermopower in molecular junctions offers complementary information to conductance measurements and is becoming essential for the understanding of transport processes at the nanoscale. In this review, we discuss the recent advances in the study of the thermoelectric properties of molecular junctions. After presenting the theoretical background for thermoelectricity at the nanoscale, we review the experimental techniques for measuring the thermopower in these systems and discuss the main results. Finally, we consider the challenges in the application of molecular junctions in viable thermoelectric devices. PMID:27277330

  7. Electronic properties of nanotube junctions

    NASA Astrophysics Data System (ADS)

    Lambin, Ph.; Meunier, V.

    1998-08-01

    The possibility of realizing junctions between two different nanotubes has recently attracted a great interest, even though much remains to be done for putting this idea in concrete form. Pentagon-heptagon pair defects in the otherwise perfect graphitic network make such connections possible, with virtually infinite varieties. In this paper, the literature devoted to nanotube junctions is briefly reviewed. A special emphasize is put on the electronic properties of C nanotube junctions, together with an indication on how their current-voltage characteristics may look like.

  8. Thermal conductance of superlattice junctions

    SciTech Connect

    Lu, Simon; McGaughey, Alan J. H.

    2015-05-15

    We use molecular dynamics simulations and the lattice-based scattering boundary method to compute the thermal conductance of finite-length Lennard-Jones superlattice junctions confined by bulk crystalline leads. The superlattice junction thermal conductance depends on the properties of the leads. For junctions with a superlattice period of four atomic monolayers at temperatures between 5 and 20 K, those with mass-mismatched leads have a greater thermal conductance than those with mass-matched leads. We attribute this lead effect to interference between and the ballistic transport of emergent junction vibrational modes. The lead effect diminishes when the temperature is increased, when the superlattice period is increased, and when interfacial disorder is introduced, but is reversed in the harmonic limit.

  9. Josephson junction Q-spoiler

    DOEpatents

    Clarke, John; Hilbert, Claude; Hahn, Erwin L.; Sleator, Tycho

    1988-01-01

    An automatic Q-spoiler comprising at least one Josephson tunnel junction connected in an LC circuit for flow of resonant current therethrough. When in use in a system for detecting the magnetic resonance of a gyromagnetic particle system, a high energy pulse of high frequency energy irradiating the particle system will cause the critical current through the Josephson tunnel junctions to be exceeded, causing the tunnel junctions to act as resistors and thereby damp the ringing of the high-Q detection circuit after the pulse. When the current has damped to below the critical current, the Josephson tunnel junctions revert to their zero-resistance state, restoring the Q of the detection circuit and enabling the low energy magnetic resonance signals to be detected.

  10. Josephson junction Q-spoiler

    DOEpatents

    Clarke, J.; Hilbert, C.; Hahn, E.L.; Sleator, T.

    1986-03-25

    An automatic Q-spoiler comprising at least one Josephson tunnel junction connected in an LC circuit for flow of resonant current therethrough. When in use in a system for detecting the magnetic resonance of a gyromagnetic particle system, a high energy pulse of high frequency energy irradiating the particle system will cause the critical current through the Josephson tunnel junctions to be exceeded, causing the tunnel junctions to act as resistors and thereby damp the ringing of the high-Q detection circuit after the pulse. When the current has damped to below the critical current, the Josephson tunnel junctions revert to their zero-resistance state, restoring the Q of the detection circuit and enabling the low energy magnetic resonance signals to be detected.

  11. Electronic thermometry in tunable tunnel junction

    DOEpatents

    Maksymovych, Petro

    2016-03-15

    A tunable tunnel junction thermometry circuit includes a variable width tunnel junction between a test object and a probe. The junction width is varied and a change in thermovoltage across the junction with respect to the change in distance across the junction is determined. Also, a change in biased current with respect to a change in distance across the junction is determined. A temperature gradient across the junction is determined based on a mathematical relationship between the temperature gradient, the change in thermovoltage with respect to distance and the change in biased current with respect to distance. Thermovoltage may be measured by nullifying a thermoelectric tunneling current with an applied voltage supply level. A piezoelectric actuator may modulate the probe, and thus the junction width, to vary thermovoltage and biased current across the junction. Lock-in amplifiers measure the derivatives of the thermovoltage and biased current modulated by varying junction width.

  12. Efficacy of landiolol for the treatment of junctional ectopic tachycardia resulting from sepsis.

    PubMed

    Oka, Hideharu; Sugimoto, Masaya; Azuma, Hiroshi

    2016-01-01

    Junctional ectopic tachycardia, after surgery for CHD, is a serious arrhythmia that can cause increased morbidity and mortality. We report a case of junctional ectopic tachycardia, preceded by sepsis, in a 4-year-old girl, 31 months after open-heart surgery. She was successfully treated using low-dose landiolol hydrochloride. PMID:25785611

  13. Diencephalic-mesencephalic junction dysplasia: a novel recessive brain malformation.

    PubMed

    Zaki, Maha S; Saleem, Sahar N; Dobyns, William B; Barkovich, A James; Bartsch, Hauke; Dale, Anders M; Ashtari, Manzar; Akizu, Naiara; Gleeson, Joseph G; Grijalvo-Perez, Ana Maria

    2012-08-01

    We describe six cases from three unrelated consanguineous Egyptian families with a novel characteristic brain malformation at the level of the diencephalic-mesencephalic junction. Brain magnetic resonance imaging demonstrated a dysplasia of the diencephalic-mesencephalic junction with a characteristic 'butterfly'-like contour of the midbrain on axial sections. Additional imaging features included variable degrees of supratentorial ventricular dilatation and hypoplasia to complete agenesis of the corpus callosum. Diffusion tensor imaging showed diffuse hypomyelination and lack of an identifiable corticospinal tract. All patients displayed severe cognitive impairment, post-natal progressive microcephaly, axial hypotonia, spastic quadriparesis and seizures. Autistic features were noted in older cases. Talipes equinovarus, non-obstructive cardiomyopathy and persistent hyperplastic primary vitreous were additional findings in two families. One of the patients required shunting for hydrocephalus; however, this yielded no change in ventricular size suggestive of dysplasia rather than obstruction. We propose the term 'diencephalic-mesencephalic junction dysplasia' to characterize this autosomal recessive malformation. PMID:22822038

  14. Octagonal Defects at Carbon Nanotube Junctions

    PubMed Central

    Jaskólski, W.; Pelc, M.; Chico, Leonor; Ayuela, A.

    2013-01-01

    We investigate knee-shaped junctions of semiconductor zigzag carbon nanotubes. Two dissimilar octagons appear at such junctions; one of them can reconstruct into a pair of pentagons. The junction with two octagons presents two degenerate localized states at Fermi energy (EF). The reconstructed junction has only one state near EF, indicating that these localized states are related to the octagonal defects. The inclusion of Coulomb interaction splits the localized states in the junction with two octagons, yielding an antiferromagnetic system. PMID:24089604

  15. Properties of planar Nb/{alpha}-Si/Nb Josephson junctions with various degrees of doping of the {alpha}-Si layer

    SciTech Connect

    Gudkov, A. L.; Kupriyanov, M. Yu.; Samus', A. N.

    2012-05-15

    The properties of Nb/{alpha}-Si/Nb planar Josephson junctions with various degrees of doping of the amorphous silicon layer are experimentally studied. Tungsten is used as a doping impurity. The properties of the Josephson junctions are shown to change substantially when the degree of doping of the {alpha}-Si layer changes: a current transport mechanism and the shape of the current-voltage characteristic of the junctions change. Josephson junctions with SNS-type conduction are formed in the case of a fully degenerate {alpha}-Si layer. The properties of such junctions are described by a classical resistive model. Josephson junctions with a resonance mechanism of current transport through impurity centers are formed at a lower degree of doping of the {alpha}-Si layer. The high-frequency properties of such junctions are shown to change. The experimental results demonstrate that these junctions are close to SINIS-type Josephson junctions.

  16. Joint measurement of current-phase relations and transport properties of hybrid junctions using a three junctions superconducting quantum interference device

    SciTech Connect

    Basset, J.; Delagrange, R.; Weil, R.; Kasumov, A.; Bouchiat, H.; Deblock, R.

    2014-07-14

    We propose a scheme to measure both the current-phase relation and differential conductance dI/dV of a superconducting junction, in the normal and the superconducting states. This is done using a dc Superconducting Quantum Interference Device with two Josephson junctions in parallel with the device under investigation and three contacts. As a demonstration, we measure the current-phase relation and dI/dV of a small Josephson junction and a carbon nanotube junction. In this latter case, in a regime where the nanotube is well conducting, we show that the non-sinusoidal current phase relation we find is consistent with the theory for a weak link, using the transmission extracted from the differential conductance in the normal state. This method holds great promise for future investigations of the current-phase relation of more exotic junctions.

  17. Computer-aided design of stripline ferrite junction circulators

    NASA Technical Reports Server (NTRS)

    Uzdy, Z.

    1980-01-01

    A general design procedure is presented for stripline Y-junction circulators employing solid dielectric between ground planes. The resonator design and impedance matching are derived in a form suitable for computer evaluation. The procedure is applicable to cases where either the circulator bandwidth or the ground plane spacing is specified. An experimental S-band switching circulator design illustrates the technique.

  18. Junction problems for thin inclusions in elastic bodies

    NASA Astrophysics Data System (ADS)

    Khludnev, A. M.

    2016-06-01

    Equilibrium problems for a 2D elastic bodies with thin Euler-Bernoulli and Timoshenko elastic inclusions are considered. It is assumed that inclusions have a joint point, and a junction problem for these inclusions is analyzed. Existence of solutions is proved, and different equivalent formulations of problems are discussed. In particular, junction conditions at the joint point are found. A delamination of the elastic inclusions is also assumed. In this case, inequality type boundary conditions are imposed at the crack faces to prevent a mutual penetration between crack faces. A convergence to infinity of a rigidity parameter of the elastic inclusions is investigated. Limit problems are analyzed.

  19. Quantum phases in intrinsic Josephson junctions: Quantum magnetism analogy

    NASA Astrophysics Data System (ADS)

    Machida, Masahiko; Kobayashi, Keita; Koyama, Tomio

    2013-08-01

    We explore quantum phases in intrinsic Josephson junction (IJJ) stacks, whose in-plane area is so small that the capacitive coupling has a dominant role in the superconducting phase dynamics. In such cases, the effective Hamiltonian for the superconducting phase can be mapped onto that of one-dimensional ferromagnetically-interacting spin model, whose spin length S depends on the magnitude of the on-site Coulomb repulsion. The ferromagnetic model for IJJ’s prefers synchronized quantum features in contrast to the antiferromagnetically-interacting model in the conventional Josephson junction arrays.

  20. Single intrinsic Josephson junction with double-sided fabrication technique

    NASA Astrophysics Data System (ADS)

    You, L. X.; Torstensson, M.; Yurgens, A.; Winkler, D.; Lin, C. T.; Liang, B.

    2006-05-01

    We make stacks of intrinsic Josephson junctions (IJJs) embedded in the bulk of very thin (d⩽100nm) Bi2Sr2CaCu2O8+x single crystals. By precisely controlling the etching depth during the double-sided fabrication process, the stacks can be reproducibly tailor-made to be of any microscopic height (0-9nmcase of a single junction. We discuss reproducible gaplike features in the current-voltage characteristics of the samples at high bias.

  1. Vortex depinning in Josephson-junction arrays

    NASA Astrophysics Data System (ADS)

    Dang, E. K. F.; Györffy, B. L.

    1993-02-01

    On the basis of a simple model we study the supercurrent-carrying capacity of a planar array of Josephson junctions. In particular we investigate the zero-temperature vortex-depinning current iBc, which is the largest supercurrent in an array containing one extra vortex on top of the ground-state vortex superlattice induced by an external magnetic field f. In the zero-field, f=0, case our results support the tilted-sinusoidal vortex-potential description of previous workers. However, in the fully frustrated, f=1/2 case, a more careful interpretation is required. We find that on the application of a transport current, the resulting vortex motion is not that of the extra vortex moving over a rigid field-induced vortex background. Rather, a vortex belonging to the checkerboard ground-state pattern first crosses over a junction into a neighboring ``empty'' plaquette. Then, the ``extra'' vortex moves to take its place. Our interpretation is based on a linear stability analysis, with the onset of vortex motion being associated with the vanishing of one eigenvalue of the stability matrix. Further applications of the method are suggested.

  2. Dynamics of domain wall networks with junctions

    SciTech Connect

    Avelino, P. P.; Oliveira, J. C. R. E.; Martins, C. J. A. P.; Menezes, J.; Menezes, R.

    2008-11-15

    We use a combination of analytic tools and an extensive set of the largest and most accurate three-dimensional field theory numerical simulations to study the dynamics of domain wall networks with junctions. We build upon our previous work and consider a class of models which, in the limit of large number N of coupled scalar fields, approaches the so-called ''ideal'' model (in terms of its potential to lead to network frustration). We consider values of N between N=2 and N=20, and a range of cosmological epochs, and we also compare this class of models with other toy models used in the past. In all cases we find compelling evidence for a gradual approach to scaling, strongly supporting our no-frustration conjecture. We also discuss the various possible types of junctions (including cases where there is a hierarchy of them) and their roles in the dynamics of the network. Finally, we provide a cosmological Zel'dovich-type bound on the energy scale of this kind of defect network: it must be lower than 10 keV.

  3. Transport in Carbon Nanotube Junctions

    NASA Astrophysics Data System (ADS)

    Khoo, K. H.; Chelikowsky, James R.

    2008-03-01

    There is growing interest in the use of carbon nanotube thin films as transparent electrical conductors and thin-film transistors owing to their high optical transmittance, low sheet resistivity, and ease of fabrication. [1,2] A major contribution to the sheet resistivity originates at nanotube junctions, as electrical contact is typically poor between adjacent nanotubes. It is thus important to characterize carbon nanotube junctions in order to understand the conduction properties of nanotube thin films. To this end, we have performed ab initio density functional theory calculations to investigate the structural, electronic and transport properties of carbon nanotube junctions as a function of nanotube chirality and contact geometry [1] Z. Wu et al., Science 305, 1273 (2004) [2] E. S. Snow, J. P. Novak, P. M. Campbell, and D. Park, Appl. Phys. Lett. 82, 2145 (2003).

  4. Basilar Artery Aneurysm at a Persistent Trigeminal Artery Junction

    PubMed Central

    Aguiar, G.B.; Conti, M.L.M.; Veiga, J.C.E.; Jory, M.; Souza, R.B.

    2011-01-01

    Summary The trigeminal artery is an anastomosis between the embryonic precursors of the vertebrobasilar and carotid systems, and may persist into adult life. The association of the persistent primitive trigeminal artery (PTA) with cerebral aneurysm is well documented in the literature and, in general, aneurysms are located in the anterior circulation. We describe a patient who presented with a panencephalic Fisher III subarachnoid hemorrhage due to rupture of an intracranial aneurysm. Digital arteriography showed a saccular aneurysm in the middle third of the basilar artery, adjacent to the junction with a persistent trigeminal artery. She was submitted to endovascular treatment with embolization of the basilar artery aneurysm with coils. Aneurysms at the PTA junction with the basilar artery are rare. This paper describes a case of PTA associated with an aneurysm in the basilar artery at PTA junction and briefly reviews the literature. PMID:22005697

  5. Detection of noise-corrupted sinusoidal signals with Josephson junctions

    NASA Astrophysics Data System (ADS)

    Filatrella, Giovanni; Pierro, Vincenzo

    2010-10-01

    We investigate the possibility of exploiting the speed and low noise features of Josephson junctions for detecting sinusoidal signals masked by Gaussian noise. We show that the escape time from the static locked state of a Josephson junction is very sensitive to a small periodic signal embedded in the noise, and therefore the analysis of the escape times can be employed to reveal the presence of the sinusoidal component. We propose and characterize two detection strategies: in the first, the initial phase is supposedly unknown (incoherent strategy), while in the second, the signal phase remains unknown but is fixed (coherent strategy). Our proposals are both suboptimal, with the linear filter being the optimal detection strategy, but they present some remarkable features, such as resonant activation, that make detection through Josephson junctions appealing in some special cases.

  6. Length and energy gap dependences of thermoelectricity in nanostructured junctions.

    PubMed

    Asai, Yoshihiro

    2013-04-17

    The possibilities of an enhanced thermoelectric figure of merit value, ZT, in a nanostructured junction are examined for a wide range of parameter values in a theoretical model. Our research shows that the figure of merit can take a very large maximum, which depends both on the length and the energy gap values. The maximum of ZT is achieved when the Fermi level of the electrodes is aligned to the edge of the electronic transmission function of the junction, where both the conductance and the Seebeck constant are significantly enhanced. On the basis of our results, we conclude that nanowires and molecular junctions form a special class of systems where a large ZT can be expected in some cases. PMID:23528878

  7. Craniocervical junction tuberculosis: Usual pathology at an unusual site

    PubMed Central

    Nayak, Biswaranjan; Patnaik, Sanjeev; Sahoo, Prafulla Kumar; Biswal, Debabrata

    2015-01-01

    Background: Tuberculosis (TB) of the craniocervical junction is rare even where the condition is endemic. It poses problems in both diagnosis and management if not managed in time it may cause life-threatening complications. Case Description: An 18-year-old male patient presented with pain in the nape of the neck since 12 months duration which was not improving with medication. After magnetic resonance imaging of cervical spine, he was diagnosed as craniocervical junction TB. We did a transoral decompression of abscess with biopsy along with posterior decompression of cord and occipitocervical fusion. Biopsy of pathological material came as TB. He was advised for anti-tubercular therapy for 18 months. Conclusion: Although craniocervical junction TB is a rare disease, the outcome of treatment is good. Antituberculous drug therapy remains the mainstay of treatment after confirming the diagnosis. The surgical management options include transoral decompression with or without posterior fusion, depending upon the presence and persistence of atlantoaxial instability. PMID:26229730

  8. Theoretical exploration of Josephson Plasma Emission in Intrinsic Josephson Junctions

    SciTech Connect

    Tachiki, M.; Machida, M.

    2000-07-18

    In this paper, the authors theoretically predict the best efficient way for electromagnetic wave emission by Josephson plasma excitation in intrinsic Josephson junctions. First, they briefly derive basic equations describing dynamics of phase differences inside junction sites in intrinsic Josephson junctions, and review the nature of Josephson plasma excitation modes based on the equations. Especially, they make an attention to that Josephson plasma modes have much different dispersion relations depending on the propagating directions and their different modes can be recognized as N standing waves propagating along ah-plane in cases of finite stacked systems composed of N junctions. Second, they consider how to excite their modes and point out that excitations of in-phase mode with the highest propagation velocity among their N modes are the most efficient way for electromagnetic wave emissions. Finally, they clarify that in-phase excitations over all junctions are possible by using Josephson vortex flow states. They show simulation results of Josephson vortex flow states resonating with some Josephson plasma modes and predict that superradiance of electromagnetic field may occur in rectangular vortex flow state in which spatiotemporal oscillations of electromagnetic fields are perfectly in-phase.

  9. Lattice-pseudospin and spin-valley polarizations in dual ferromagnetic-gated silicene junction

    NASA Astrophysics Data System (ADS)

    Chantngarm, Peerasak; Yamada, Kou; Soodchomshom, Bumned

    2016-06-01

    We study spin-valley and lattice-pseudospin currents in a dual ferromagnetic-gated silicene-based junction. Silicene has buckled atomic structure which allows us to take sublattice-dependent ferromagnetism into account in the investigation. One of the study results show that transmission at the junctions exhibits anisotropic property only in anti-parallel cases. Interestingly, the studied junctions can be switched from a pure spin-polarizer to a pure valley-polarizer by reversing directions of exchange fields in the parallel junctions. The perfect control of spin-valley currents can be done only in the parallel cases and its resolution can be enhanced by increasing gate potential between the ferromagnetic barriers. The asymmetric barriers of anti-parallel junction is found to destroy both spin and valley filtering effects and yield a novel result, pure sub-lattice pseudospin polarization. The current in the anti-parallel junctions can be controlled to flow solely in either A or B sub-lattice, saying that the controllable lattice current in silicene is created in double ferromagnetic-gated junction. Our work reveals the potential of dual ferromagnetic-gated silicene junction which may be possible for applications in spin-valleytronics and lattice-pseudospintronics.

  10. Conducting polyaniline nanowire electrode junction

    NASA Astrophysics Data System (ADS)

    Gaikwad, Sumedh; Bodkhe, Gajanan; Deshmukh, Megha; Patil, Harshada; Rushi, Arti; Shirsat, Mahendra D.; Koinkar, Pankaj; Kim, Yun-Hae; Mulchandani, Ashok

    2015-03-01

    In this paper, a synthesis of conducting polyaniline nanowires electrode junction (CPNEJ) has been reported. Conducting polyaniline nanowires electrode junction on Si/SiO2 substrate (having 3 μm gap between two gold microelectrodes) is prepared. Polyaniline nanowires with diameter (ca. 140 nm to 160 nm) were synthesized by one step electrochemical polymerization using galvanostatic (constant current) technique to bridge this gap. The surface morphology of CPNEJ was studied by scanning electron microscope (SEM). The synthesized CPNEJ is an excellent platform for biosensor applications.

  11. Work fluctuations in bosonic Josephson junctions

    NASA Astrophysics Data System (ADS)

    Lena, R. G.; Palma, G. M.; De Chiara, G.

    2016-05-01

    We calculate the first two moments and full probability distribution of the work performed on a system of bosonic particles in a two-mode Bose-Hubbard Hamiltonian when the self-interaction term is varied instantaneously or with a finite-time ramp. In the instantaneous case, we show how the irreversible work scales differently depending on whether the system is driven to the Josephson or Fock regime of the bosonic Josephson junction. In the finite-time case, we use optimal control techniques to substantially decrease the irreversible work to negligible values. Our analysis can be implemented in present-day experiments with ultracold atoms and we show how to relate the work statistics to that of the population imbalance of the two modes.

  12. Extended cervico-thoracic metastasectomy for testicular non-seminomatous germ cell tumour masses through an inverse T and combined collar incision.

    PubMed

    Schweiger, Thomas; Hoetzenecker, Konrad; Taghavi, Shahrokh; Klepetko, Walter

    2015-05-01

    Non-seminomatous germ cell tumours (NSGCT) are the most common malignancy from testicular origin in young males. They are characterized by early formation of metastases along retroperitoneal and subsequent mediastinal lymph node stations. Following cisplatin-based induction chemotherapy, residual tumour masses should be removed surgically, although this implies the need for extended procedures. Such an approach can result in cure rates of over 70%. Herein, we report 2 cases of maximally extended surgery for metastatic malignant germ cell tumour of the testis. In both patients, diagnostic work-up revealed a NSGCT with retroperitoneal, mediastinal and cervical lymph node metastases. Multimodal protocols including induction chemotherapy and surgical removal of all primary and secondary tumour masses with curative intent were applied. An 'inverse T' incision in combination with a collar incision was chosen to approach the excessive supra-diaphragmatic tumour spread. This large-scaled surgical access offered an excellent exposure and allowed complete resection of all cervical and thoracic metastases in both patients. Abdominal tumour masses were resected through a standard median laparotomy. These 2 cases illustrate that complete tumour resection is feasible even in stages of NSGCT with generalized lymphatic spread. Metastasectomy should be offered to NSGCT patients despite the necessity of extended surgical approaches. PMID:24925077

  13. Simple Electronic Analog of a Josephson Junction.

    ERIC Educational Resources Information Center

    Henry, R. W.; And Others

    1981-01-01

    Demonstrates that an electronic Josephson junction analog constructed from three integrated circuits plus an external reference oscillator can exhibit many of the circuit phenomena of a real Josephson junction. Includes computer and other applications of the analog. (Author/SK)

  14. GLIAL ANKYRINS FACILITATE PARANODAL AXOGLIAL JUNCTION ASSEMBLY

    PubMed Central

    Chang, Kae-Jiun; Zollinger, Daniel R.; Susuki, Keiichiro; Sherman, Diane L.; Makara, Michael A.; Brophy, Peter J.; Cooper, Edward C.; Bennett, Vann; Mohler, Peter J.; Rasband, Matthew N.

    2014-01-01

    Neuron-glia interactions establish functional membrane domains along myelinated axons. These include nodes of Ranvier, paranodal axoglial junctions, and juxtaparanodes. Paranodal junctions are the largest vertebrate junctional adhesion complex, are essential for rapid saltatory conduction, and contribute to assembly and maintenance of nodes. However, the molecular mechanisms underlying paranodal junction assembly are poorly understood. Ankyrins are cytoskeletal scaffolds traditionally associated with Na+ channel clustering in neurons and important for membrane domain establishment and maintenance in many cell types. Here, we show that ankyrinB, expressed by Schwann cells, and ankyrinG, expressed by oligodendrocytes, are highly enriched at the glial side of paranodal junctions where they interact with the essential glial junctional component neurofascin 155. Conditional knockout of ankyrins in oligodendrocytes disrupts paranodal junction assembly and delays nerve conduction during early development in mice. Thus, glial ankyrins function as major scaffolds that facilitate early and efficient paranodal junction assembly in the developing central nervous system. PMID:25362471

  15. Glial ankyrins facilitate paranodal axoglial junction assembly.

    PubMed

    Chang, Kae-Jiun; Zollinger, Daniel R; Susuki, Keiichiro; Sherman, Diane L; Makara, Michael A; Brophy, Peter J; Cooper, Edward C; Bennett, Vann; Mohler, Peter J; Rasband, Matthew N

    2014-12-01

    Neuron-glia interactions establish functional membrane domains along myelinated axons. These include nodes of Ranvier, paranodal axoglial junctions and juxtaparanodes. Paranodal junctions are the largest vertebrate junctional adhesion complex, and they are essential for rapid saltatory conduction and contribute to assembly and maintenance of nodes. However, the molecular mechanisms underlying paranodal junction assembly are poorly understood. Ankyrins are cytoskeletal scaffolds traditionally associated with Na(+) channel clustering in neurons and are important for membrane domain establishment and maintenance in many cell types. Here we show that ankyrin-B, expressed by Schwann cells, and ankyrin-G, expressed by oligodendrocytes, are highly enriched at the glial side of paranodal junctions where they interact with the essential glial junctional component neurofascin 155. Conditional knockout of ankyrins in oligodendrocytes disrupts paranodal junction assembly and delays nerve conduction during early development in mice. Thus, glial ankyrins function as major scaffolds that facilitate early and efficient paranodal junction assembly in the developing CNS. PMID:25362471

  16. Measurement of tunnel junction resistance during formation

    SciTech Connect

    Barber, W.C.; Johnson, R.T.; Lee, J.S.; Laws, K.E.; Bland, R.W. )

    1993-11-01

    The authors have measured the characteristics of aluminum tunnel junctions during and immediately after the formation of the junction. This has permitted us to observe changes in the oxide barrier, in vacuum and in air. By observing the barrier resistance during sputtering, they were able to diagnose and correct problems due to plasma discharges which were damaging the junctions. They report preliminary results from junctions passivated with a silicon nitride cap layer.

  17. Layer Engineering of 2D Semiconductor Junctions.

    PubMed

    He, Yongmin; Sobhani, Ali; Lei, Sidong; Zhang, Zhuhua; Gong, Yongji; Jin, Zehua; Zhou, Wu; Yang, Yingchao; Zhang, Yuan; Wang, Xifan; Yakobson, Boris; Vajtai, Robert; Halas, Naomi J; Li, Bo; Xie, Erqing; Ajayan, Pulickel

    2016-07-01

    A new concept for junction fabrication by connecting multiple regions with varying layer thicknesses, based on the thickness dependence, is demonstrated. This type of junction is only possible in super-thin-layered 2D materials, and exhibits similar characteristics as p-n junctions. Rectification and photovoltaic effects are observed in chemically homogeneous MoSe2 junctions between domains of different thicknesses. PMID:27136275

  18. The Yolla Bolly junction revisited

    SciTech Connect

    Blake, M.C.; Jayko, A.S. ); Jones, D.L. . Dept. of Geology and Geophysics); Engebretson, D.C. . Dept. of Geology)

    1993-04-01

    West of Red Bluff, California, rocks of the northern Coast Ranges, Klamath-Sierra Nevada, and Great Valley provinces come together at what has been called the Yolla Bolly junction. Mapping of the Red Bluff and Willows 1:100,000 quadrangles has greatly clarified the enigmatic features of this complex area. Terranes of the Klamath Mountains and their Cretaceous sedimentary cover have been thrust northwestward over the Elder Creek terrane and Franciscan rocks, north of the left-lateral Cold Fork fault zone. The Condrey Mountain window (Franciscan Pickett Peak terrane) provides a measure of the magnitude of this thrusting (ca 90 km). South of the Cold Fork fault zone, the Franciscan and Elder Creek terranes were driven southeastward as tectonic wedges onto Sierran-Klamath basement. Timing of this scissor-tectonics is not constrained near the junction, but further north in southwest Oregon, Lower Eocene strata were deformed by overthrusting of the Klamath block whereas Upper Eocene strata overlap the thrust, indicating that thrusting occurred between about 52 and 60 Ma. Plate reconstructions for this time interval indicate the close proximity of the Kula-Farallon-North America triple junction and that old (ca 100 m.y.) Farallon lithosphere was being subducted north of the junction whereas to the south, very young (ca 10 m.y.) Kula plate was presumably obducted onto North America.

  19. GAP JUNCTION FUNCTION AND CANCER

    EPA Science Inventory

    Gap Junctions (GJs) provide cell-to-cell communication (GJIC) of essential metabolites and ions. Js allow tissues to average responses, clear waste products, and minimize the effects of xenobiotics by dilution and allowing steady-state catabolism. any chemicals can adversely affe...

  20. Improved Solar-Cell Tunnel Junction

    NASA Technical Reports Server (NTRS)

    Daud, T.; Kachare, A.

    1986-01-01

    Efficiency of multiple-junction silicon solar cells increased by inclusion of p+/n+ tunnel junctions of highly doped GaP between component cells. Relatively low recombination velocity at GaP junction principal reason for recommending this material. Relatively wide band gap also helps increase efficiency by reducing optical losses.

  1. 27 CFR 9.164 - River Junction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false River Junction. 9.164... River Junction. (a) Name. The name of the viticultural area described in this section is “River Junction.” (b) Approved maps. The appropriate maps for determining the boundaries of the River...

  2. 27 CFR 9.164 - River Junction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false River Junction. 9.164... River Junction. (a) Name. The name of the viticultural area described in this section is “River Junction.” (b) Approved maps. The appropriate maps for determining the boundaries of the River...

  3. Metallic Electrode: Semiconducting Nanotube Junction Model

    NASA Technical Reports Server (NTRS)

    Yamada, Toshishige; Biegel, Bryon (Technical Monitor)

    2001-01-01

    A model is proposed for two observed current-voltage (I-V) patterns in an experiment with a scanning tunneling microscope tip and a carbon nanotube [Collins et al., Science 278, 100 ('97)]. We claim that there are two contact modes for a tip (metal) -nanotube semi conductor) junction depending whether the alignment of the metal and semiconductor band structure is (1) variable (vacuum-gap) or (2) fixed (touching) with V. With the tip grounded, the tunneling case in (1) would produce large dI/dV with V > 0, small dI/dV with V < 0, and I = 0 near V = 0 for an either n- or p-nanotube. However, the Schottky mechanism in (2) would result in forward current with V < 0 for an n-nanotube, while with V > 0 for an p-nanotube. The two observed I-V patterns are thus entirely explained by a tip-nanotube contact of the two types, where the nanotube must be n-type. We apply this picture to the source-drain I-V characteristics in a long nanotube-channel field-effect-transistor (Zhou et al., Appl. Phys. Lett. 76, 1597 ('00)], and show that two independent metal-semiconductor junctions connected in series are responsible for the observed behavior.

  4. Nonlocal supercurrent in mesoscopic multiterminal SNS Josephson junction in the low-temperature limit

    NASA Astrophysics Data System (ADS)

    Golikova, T. E.; Wolf, M. J.; Beckmann, D.; Batov, I. E.; Bobkova, I. V.; Bobkov, A. M.; Ryazanov, V. V.

    2014-03-01

    A nonlocal supercurrent was observed in mesoscopic planar SNS Josephson junctions with additional normal-metal electrodes, where nonequilibrium quasiparticles were injected from a normal-metal electrode into one of the superconducting banks of the Josephson junction in the absence of a net transport current through the junction. We claim that the observed effect is due to a supercurrent counterflow, appearing to compensate for the quasiparticle flow in the SNS weak link. We have measured the responses of SNS junctions for different distances between the quasiparticle injector and the SNS junction at temperatures far below the superconducting transition temperature. The charge-imbalance relaxation length was estimated by using a modified Kadin, Smith, and Skocpol scheme in the case of a planar geometry. The model developed allows us to describe the interplay of charge imbalance and Josephson effects in the nanoscale proximity system in detail.

  5. Interplay of Bias-Driven Charging and the Vibrational Stark Effect in Molecular Junctions.

    PubMed

    Li, Yajing; Zolotavin, Pavlo; Doak, Peter; Kronik, Leeor; Neaton, Jeffrey B; Natelson, Douglas

    2016-02-10

    We observe large, reversible, bias driven changes in the vibrational energies of PCBM based on simultaneous transport and surface-enhanced Raman spectroscopy (SERS) measurements on PCBM-gold junctions. A combination of linear and quadratic shifts in vibrational energies with voltage is analyzed and compared with similar measurements involving C60-gold junctions. A theoretical model based on density functional theory (DFT) calculations suggests that both a vibrational Stark effect and bias-induced charging of the junction contribute to the shifts in vibrational energies. In the PCBM case, a linear vibrational Stark effect is observed due to the permanent electric dipole moment of PCBM. The vibrational Stark shifts shown here for PCBM junctions are comparable to or larger than the charging effects that dominate in C60 junctions. PMID:26814562

  6. Dirac supercurrent in an asymmetric graphene-based SG 1/F B/SG 2 junction

    NASA Astrophysics Data System (ADS)

    Soodchomshom, Bumned; Tang, I.-Ming; Hoonsawat, Rassmidara

    2009-02-01

    The Josephson current in an asymmetric graphene-based SG 1/F B/SG 2 junction where SG 1,2 are graphene layers which have been induced into two superconducting states having order parameters Δ1 and Δ2 ( Δ1 ≠ Δ2) on the left and right sides of a ferromagnetic barrier F B of thickness d, respectively is studied. The presence of the exchange energy Eex and the gate potential VG in the barrier F B are taken into account. For the case of k///0, we find that the Josephson current depends on the exchange energy but is independent of the gate voltage. We find that increasing Δ2 can induce the junction to become a π-junction. This does not occur in the case of similar junctions having conventional superconductors in them. The critical current at zero temperature for Δ2 → ∞ has the form I(Δ2→∞)=2eΔ1/ℏ=2I(Δ2=Δ1). This behavior of the Josephson current in a graphene junction is quite different from that of the supercurrent in conventional asymmetric junctions. For those junctions, it is predicted that I∝Δ1Δ2, leading to IC → ∞ as Δ2 → ∞. A transition from a 0-junction to a π-junction is observed as χex ( χ∼2Ed/ℏv) is increased. In a 0-junction, the spin supercurrents arising from the spin dependent Andreev energy levels do not vanish. This leads to IS = I↑ + I↓ = 0 but with I↑ = - I↓ ≠ 0.

  7. Area-dependence of spin-triplet supercurrent in ferromagnetic Josephson junctions

    NASA Astrophysics Data System (ADS)

    Wang, Yixing; Pratt, William P., Jr.; Birge, Norman O.

    2012-02-01

    Spin-triplet supercurrents in strong ferromagnetic Josephson junctions were reported by several groups in 2010. At the same time, the 0-π current-phase relationship of the spin-triplet supercurrent was predicted to be controllable by the magnetization orientations of different ferromagnetic layers. Our junctions contain a series of ferromagnetic layers consisting of a synthetic antiferromagnet Co/Ru/Co sandwiched between two thin magnetic layers such as PdNi or Ni [1]. When looking along the direction of current flow, one should obtain 0 junctions if the rotation direction of magnetizations is the same from one to the next, and π junctions when the opposite rotation direction is the case. Since our magnetic layers have multiple domains in the virgin state, we should expect 0 and π phases to alternate randomly in different locations in the junctions. The critical current in the virgin state should scale with the square-root of the junction area. After aligning the outer ferromagnetic layers in the same direction with an external field, the current-phase relation should be uniform across the whole junction area and the critical current should be proportional to the junction area. We will present data confirming this expectation for the magnetized state, whereas the situation for the virgin state is presently unclear. [4pt] [1] T.S. Khaire, M.A. Khasawneh, W.P. Pratt Jr and N.O. Birge, Phys. Rev. Lett. 104 137002 (2010).

  8. Molecular series-tunneling junctions.

    PubMed

    Liao, Kung-Ching; Hsu, Liang-Yan; Bowers, Carleen M; Rabitz, Herschel; Whitesides, George M

    2015-05-13

    Charge transport through junctions consisting of insulating molecular units is a quantum phenomenon that cannot be described adequately by classical circuit laws. This paper explores tunneling current densities in self-assembled monolayer (SAM)-based junctions with the structure Ag(TS)/O2C-R1-R2-H//Ga2O3/EGaIn, where Ag(TS) is template-stripped silver and EGaIn is the eutectic alloy of gallium and indium; R1 and R2 refer to two classes of insulating molecular units-(CH2)n and (C6H4)m-that are connected in series and have different tunneling decay constants in the Simmons equation. These junctions can be analyzed as a form of series-tunneling junctions based on the observation that permuting the order of R1 and R2 in the junction does not alter the overall rate of charge transport. By using the Ag/O2C interface, this system decouples the highest occupied molecular orbital (HOMO, which is localized on the carboxylate group) from strong interactions with the R1 and R2 units. The differences in rates of tunneling are thus determined by the electronic structure of the groups R1 and R2; these differences are not influenced by the order of R1 and R2 in the SAM. In an electrical potential model that rationalizes this observation, R1 and R2 contribute independently to the height of the barrier. This model explicitly assumes that contributions to rates of tunneling from the Ag(TS)/O2C and H//Ga2O3 interfaces are constant across the series examined. The current density of these series-tunneling junctions can be described by J(V) = J0(V) exp(-β1d1 - β2d2), where J(V) is the current density (A/cm(2)) at applied voltage V and βi and di are the parameters describing the attenuation of the tunneling current through a rectangular tunneling barrier, with width d and a height related to the attenuation factor β. PMID:25871745

  9. Tight Junction Proteins in Human Schwann Cell Autotypic Junctions

    PubMed Central

    Alanne, Maria H.; Pummi, Kati; Heape, Anthony M.; Grènman, Reidar; Peltonen, Juha; Peltonen, Sirkku

    2009-01-01

    Tight junctions (TJs) form physical barriers in various tissues and regulate paracellular transport of ions, water, and molecules. Myelinating Schwann cells form highly organized structures, including compact myelin, nodes of Ranvier, paranodal regions, Schmidt-Lanterman incisures, periaxonal cytoplasmic collars, and mesaxons. Autotypic TJs are formed in non-compacted myelin compartments between adjacent membrane lamellae of the same Schwann cell. Using indirect immunofluorescence and RT-PCR, we analyzed the expression of adherens junction (E-cadherin) and TJ [claudins, zonula occludens (ZO)-1, occludin] components in human peripheral nerve endoneurium, showing clear differences with published rodent profiles. Adult nerve paranodal regions contained E-cadherin, claudin-1, claudin-2, and ZO-1. Schmidt-Lanterman incisures contained E-cadherin, claudin-1, claudin-2, claudin-3, claudin-5, ZO-1, and occludin. Mesaxons contained E-cadherin, claudin-1, claudin-2, claudin-3, ZO-1, and occludin. None of the proteins studied were associated with nodal inter-Schwann cell junctions. Fetal nerve expression of claudin-1, claudin-3, ZO-1, and occludin was predominantly punctate, with a mesaxonal labeling pattern, but paranodal (ZO-1, claudin-3) and Schmidt-Lanterman incisure (claudins-1 and -3) expression profiles typical of compact myelin were visible by gestational week 37. The clear differences observed between human and published rodent nerve profiles emphasize the importance of human studies when translating the results of animal models to human diseases. (J Histochem Cytochem 57:523–529, 2009) PMID:19153196

  10. Josephson junctions and dark energy

    NASA Astrophysics Data System (ADS)

    Jetzer, Philippe; Straumann, Norbert

    2006-08-01

    In a recent paper Beck and Mackey [C. Beck, M.C. Mackey, astro-ph/0603397] argue that the argument we gave in our paper [Ph. Jetzer, N. Straumann, Phys. Lett. B 606 (2005) 77, astro-ph/0411034] to disprove their claim that dark energy can be discovered in the Lab through noise measurements of Josephson junctions is incorrect. In particular, they emphasize that the measured noise spectrum in Josephson junctions is a consequence of the fluctuation dissipation theorem, while our argument was based on equilibrium statistical mechanics. In this note we show that the fluctuation dissipation relation does not depend upon any shift of vacuum (zero-point) energies, and therefore, as already concluded in our previous paper, dark energy has nothing to do with the proposed measurements.

  11. Seebeck effect in molecular junctions.

    PubMed

    Zimbovskaya, Natalya A

    2016-05-11

    Advances in the fabrication and characterization of nanoscale systems presently allow for a better understanding of their thermoelectric properties. As is known, the building blocks of thermoelectricity are the Peltier and Seebeck effects. In the present work we review results of theoretical studies of the Seebeck effect in single-molecule junctions and similar systems. The behavior of thermovoltage and thermopower in these systems is controlled by several factors including the geometry of molecular bridges, the characteristics of contacts between the bridge and the electrodes, the strength of the Coulomb interactions between electrons on the bridge, and of electron-phonon interactions. We describe the impact of these factors on the thermopower. Also, we discuss a nonlinear Seebeck effect in molecular junctions. PMID:27073108

  12. Seebeck effect in molecular junctions

    NASA Astrophysics Data System (ADS)

    Zimbovskaya, Natalya A.

    2016-05-01

    Advances in the fabrication and characterization of nanoscale systems presently allow for a better understanding of their thermoelectric properties. As is known, the building blocks of thermoelectricity are the Peltier and Seebeck effects. In the present work we review results of theoretical studies of the Seebeck effect in single-molecule junctions and similar systems. The behavior of thermovoltage and thermopower in these systems is controlled by several factors including the geometry of molecular bridges, the characteristics of contacts between the bridge and the electrodes, the strength of the Coulomb interactions between electrons on the bridge, and of electron–phonon interactions. We describe the impact of these factors on the thermopower. Also, we discuss a nonlinear Seebeck effect in molecular junctions.

  13. Gap junctions as electrical synapses.

    PubMed

    Bennett, M V

    1997-06-01

    Gap junctions are the morphological substrate of one class of electrical synapse. The history of the debate on electrical vs. chemical transmission is instructive. One lesson is that Occam's razor sometimes cuts too deep; the nervous system does its operations in a number of different ways and a unitarian approach can lead one astray. Electrical synapses can do many things that chemical synapses can do, and do them just as slowly. More intriguing are the modulatory actions that chemical synapses can have on electrical synapses. Voltage dependence provides an important window on structure function relations of the connexins, even where the dependence may have no physiological role. The new molecular approaches will greatly advance our knowledge of where gap junctions occur and permit experimental manipulation with high specificity. PMID:9278865

  14. Thermoelectric efficiency of molecular junctions

    NASA Astrophysics Data System (ADS)

    Perroni, C. A.; Ninno, D.; Cataudella, V.

    2016-09-01

    Focus of the review is on experimental set-ups and theoretical proposals aimed to enhance thermoelectric performances of molecular junctions. In addition to charge conductance, the thermoelectric parameter commonly measured in these systems is the thermopower, which is typically rather low. We review recent experimental outcomes relative to several junction configurations used to optimize the thermopower. On the other hand, theoretical calculations provide estimations of all the thermoelectric parameters in the linear and non-linear regime, in particular of the thermoelectric figure of merit and efficiency, completing our knowledge of molecular thermoelectricity. For this reason, the review will mainly focus on theoretical studies analyzing the role of not only electronic, but also of the vibrational degrees of freedom. Theoretical results about thermoelectric phenomena in the coherent regime are reviewed focusing on interference effects which play a significant role in enhancing the figure of merit. Moreover, we review theoretical studies including the effects of molecular many-body interactions, such as electron–vibration couplings, which typically tend to reduce the efficiency. Since a fine tuning of many parameters and coupling strengths is required to optimize the thermoelectric conversion in molecular junctions, new theoretically proposed set-ups are discussed in the conclusions.

  15. Thermoelectric efficiency of molecular junctions.

    PubMed

    Perroni, C A; Ninno, D; Cataudella, V

    2016-09-21

    Focus of the review is on experimental set-ups and theoretical proposals aimed to enhance thermoelectric performances of molecular junctions. In addition to charge conductance, the thermoelectric parameter commonly measured in these systems is the thermopower, which is typically rather low. We review recent experimental outcomes relative to several junction configurations used to optimize the thermopower. On the other hand, theoretical calculations provide estimations of all the thermoelectric parameters in the linear and non-linear regime, in particular of the thermoelectric figure of merit and efficiency, completing our knowledge of molecular thermoelectricity. For this reason, the review will mainly focus on theoretical studies analyzing the role of not only electronic, but also of the vibrational degrees of freedom. Theoretical results about thermoelectric phenomena in the coherent regime are reviewed focusing on interference effects which play a significant role in enhancing the figure of merit. Moreover, we review theoretical studies including the effects of molecular many-body interactions, such as electron-vibration couplings, which typically tend to reduce the efficiency. Since a fine tuning of many parameters and coupling strengths is required to optimize the thermoelectric conversion in molecular junctions, new theoretically proposed set-ups are discussed in the conclusions. PMID:27420149

  16. Modeling of Intrinsic Josephson Junctions in High Temperature Superconductors under External Radiation in the Breakpoint Region

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu. M.; Rahmonov, I. R.; Plecenik, A.; Streltsova, O. I.; Zuev, M. I.; Ososkov, G. A.

    2016-02-01

    The current-voltage (IV) characteristics of the intrinsic Josephson junctions in high temperature superconductors under external electromagnetic radiation are calculated numerically in the parametric resonance region. We discuss a numerical method for calculation of the Shapiro step width on the amplitude of radiation. In order to accelerate computations we used parallelization by task parameter via Simple Linux Utility for Resource Management (SLURM) arrays and tested it in the case of a single junction. An analysis of the junction transitions between rotating and oscillating states in the branching region of IV-characteristics is presented.

  17. Fabrication and Tunneling Properties of Niobium/lead Josephson Junctions

    NASA Astrophysics Data System (ADS)

    Celaschi, Sergio

    High quality Josephson tunneling junctions have been fabricated by the process of electron beam evaporation of the Nb base electrode. Thermal oxidation of Nb coated and uncoated surfaces was used in order to grow the oxide barrier at room temperature. Lead was used to complete the sandwich-type structure. The tunneling properties were profoundly sensitive to the surface properties of the Nb films. We found markedly improved Josephson tunneling characteristics by depositing much higher residual resistance ratio (>100) films which in this case seemed to be single crystal. One of the main deterrents for the practical use of high quality Nb/Nb:O(,X)/Pb Josephson junctions has been the high value of the specific capacitance of the native oxides which is drastically reduced by using single crystal Nb thin films. Some of the important parameters of the junctions can be modified by coating the Nb surface. We have demonstrated that Zr, Ti, and Al can be employed as oxidized barriers on single-crystal Nb films to produce high quality Josephson junctions which preserve the low values of the dielectric constant.

  18. Logical Gates Implemented by Solitons at the Junctions Between One-Dimensional Lattices

    NASA Astrophysics Data System (ADS)

    Siccardi, Stefano; Adamatzky, Andrew

    2016-06-01

    We study propagation of solitons on one-dimensional lattices of nodes with Morse interaction between the neighboring nodes. In numerical integration, we demonstrate that solitons colliding at junctions of two lattices can implement AND, OR and NOT Boolean logic gates. The gates are determined by the geometry of the junctions and phase difference of the colliding solitons. We evaluate the feasibility of casing gates in the design of NOR gate.

  19. Formation and stability of ridge-ridge-ridge triple junctions in rheologically realistic lithosphere model

    NASA Astrophysics Data System (ADS)

    Gerya, Taras; Burov, Evgueni

    2015-04-01

    Triple junctions are probably the most remarkable features of plate boundaries since their presence constitutes one of the major demonstrations of plate tectonics theory. Divergent (R-R-R) triple junctions (at 120° and T junctions) are particular ones since their stability depends on the exact values of the relative velocities of plate divergence and hence is strongly affected by plate rheology and processes of crustal accretion. The mechanisms of their formation and long-term steadiness are not well understood even though it is commonly accepted, generally based on common sense, that the geometry and stability of triple junctions should be related to the intuitively acceptable geometric considerations that 3-branch configurations should be "stable" over the time on a 3D Earth surface. That said, most plate boundaries are in fact 2D in terms that they involve only two plates, while junctions with 3 and more branches, if even mechanically not excluded, are generally short-lived and hence rarely observed at tectonic scale. Indeed, it has been long-time suggested that triple junctions result from evolution of short-lived quadruple junctions, yet, without providing a consistent mechanical explanation or experimental demonstration of this process, due to the rheological complexity of the lithosphere and that of strain localization and crustal accretion processes. For example, it is supposed that R-R-R junctions form as result of axisymmetric mantle upwellings. However, impingement of buoyant fluid on a non-pre-stressed lithosphere should result in multiple radial cracks, as is well known from previous analog and numerical experiments. In case of uni-directionally pre-stressed lithosphere, it has also shown that linear 2D rift structures should be formed. Therefore, a complete 3D thermos-mechanically consistent approach is needed to understand the processes of formation of multi-branch junctions. With this goal we here reproduce and study the processes of multi

  20. String junction as a baryonic constituent

    NASA Astrophysics Data System (ADS)

    Kalashnikova, Yu. S.; Nefediev, A. V.

    1996-02-01

    We extend the model for QCD string with quarks to consider the Mercedes Benz string configuration describing the three-quark baryon. Under the assumption of adiabatic separation of quark and string junction motion we formulate and solve the classical equation of motion for the junction. We dare to quantize the motion of the junction, and discuss the impact of these modes on the baryon spectra.

  1. String junctions and holographic interfaces

    SciTech Connect

    Chiodaroli, Marco; Gutperle, Michael; Hung, Ling-Yan; Krym, Darya

    2011-01-15

    In this paper we study half-BPS type IIB supergravity solutions with multiple AdS{sub 3}xS{sup 3}xM{sub 4} asymptotic regions, where M{sub 4} is either T{sup 4} or K{sub 3}. These solutions were first constructed in [M. Chiodaroli, M. Gutperle, and D. Krym, J. High Energy Phys. 02 (2010) 066.] and have geometries given by the warped product of AdS{sub 2}xS{sup 2}xM{sub 4} over {Sigma}, where {Sigma} is a Riemann surface. We show that the holographic boundary has the structure of a star graph, i.e. n half-lines joined at a point. The attractor mechanism and the relation of the solutions to junctions of self-dual strings in six-dimensional supergravity are discussed. The solutions of [M. Chiodaroli, M. Gutperle, and D. Krym, J. High Energy Phys. 02 (2010) 066.] are constructed introducing two meromorphic and two harmonic functions defined on {Sigma}. We focus our analysis on solutions corresponding to junctions of three different conformal field theories and show that the conditions for having a solution charged only under Ramond-Ramond three-form fields reduce to relations involving the positions of the poles and the residues of the relevant harmonic and meromorphic functions. The degeneration limit in which some of the poles collide is analyzed in detail. Finally, we calculate the holographic boundary entropy for a junction of three CFTs and obtain a simple expression in terms of poles and residues.

  2. Role of the septate junction in the regulation of paracellular transepithelial flow.

    PubMed

    Lord, B A; DiBona, D R

    1976-12-01

    A comparison of the distribution of septate junctions in invertebrate epithelia and tight junctions in vertebrate systems suggests that these structures may be functionally analogous. This proposition is supported by the internal design of each junction which constitutes a serial arrangement of structures crossing the intercellular space between cells to effectively provide resistance to the paracellular flow of water and small molecules. We have tested the validity of such an analogy by examining whether the osmotic sensitivity of the septate junctions of planarian epidermis follow the rather striking pattern observed for the junctions of very tight vertebrate epithelia (e.g. toad urinary bladder). It has been found that the septate junctions in this system respond in similar fashion to their vertebrate counterparts, blistering with accumulated fluid when the medium outside the epidermis is made hypertonic with small, water-soluble molecules. We conclude that the two types of junction probably are functionally analogous and that, in each case, this rectified structural response to transepithelial osmotic gradients may be indicative of the role of such structures in the transport function of epithelia. PMID:993276

  3. Method for shallow junction formation

    DOEpatents

    Weiner, Kurt H.

    1996-01-01

    A doping sequence that reduces the cost and complexity of forming source/drain regions in complementary metal oxide silicon (CMOS) integrated circuit technologies. The process combines the use of patterned excimer laser annealing, dopant-saturated spin-on glass, silicide contact structures and interference effects creates by thin dielectric layers to produce source and drain junctions that are ultrashallow in depth but exhibit low sheet and contact resistance. The process utilizes no photolithography and can be achieved without the use of expensive vacuum equipment. The process margins are wide, and yield loss due to contact of the ultrashallow dopants is eliminated.

  4. Method for shallow junction formation

    DOEpatents

    Weiner, K.H.

    1996-10-29

    A doping sequence is disclosed that reduces the cost and complexity of forming source/drain regions in complementary metal oxide silicon (CMOS) integrated circuit technologies. The process combines the use of patterned excimer laser annealing, dopant-saturated spin-on glass, silicide contact structures and interference effects creates by thin dielectric layers to produce source and drain junctions that are ultrashallow in depth but exhibit low sheet and contact resistance. The process utilizes no photolithography and can be achieved without the use of expensive vacuum equipment. The process margins are wide, and yield loss due to contact of the ultrashallow dopants is eliminated. 8 figs.

  5. Thermoelectric effects in nanoscale junctions.

    PubMed

    Dubi, Yonatan; Di Ventra, Massimiliano

    2009-01-01

    Despite its intrinsic nonequilibrium origin, thermoelectricity in nanoscale systems is usually described within a static scattering approach which disregards the dynamical interaction with the thermal baths that maintain energy flow. Using the theory of open quantum systems, we show instead that unexpected properties, such as a resonant structure and large sign sensitivity, emerge if the nonequilibrium nature of this problem is considered. Our approach also allows us to define and study a local temperature, which shows hot spots and oscillations along the system according to the coupling of the latter to the electrodes. This demonstrates that Fourier's lawa paradigm of statistical mechanicsis generally violated in nanoscale junctions. PMID:19072125

  6. An improved junction capacitance model for junction field-effect transistors

    NASA Astrophysics Data System (ADS)

    Ding, Hao; Liou, Juin J.; Cirba, Claude R.; Green, Keith

    2006-07-01

    A new junction capacitance model for the four-terminal junction field-effect transistor (JFET) is presented. With a single expression, the model, which is valid for different temperatures and a wide range of bias conditions, describes correctly the JFET junction capacitance behavior and capacitance drop-off phenomenon. The model has been verified using experimental data measured at Texas Instruments.

  7. Bilaterally obstructed ureteropelvic junction of the upper moieties in a complete duplex collecting system.

    PubMed

    Latayan, Michael Jonathan R; Dator, Jose Dante P; Torres, Carlos Ramon N

    2008-02-01

    Maternal ultrasound is a routine examination in prenatal evaluation. The number of fetal abnormalities detected has been increasing, and includes fetal hydronephrosis which is secondary to ureteropelvic junction obstruction in 80% of cases. We report a case of a 1-year-old female infant with hydronephrosis prenatally detected by ultrasound. After close postnatal follow-up and diagnosis, she eventually underwent a definitive reconstructive procedure. This is the first reported case of a bilateral ureteropelvic junction obstruction of the upper moieties of a duplex collecting system. PMID:18631901

  8. Magnetoresistance in Boron Carbide junctions

    NASA Astrophysics Data System (ADS)

    Day, Ellen; Sokolov, A.; Baruth, A.; Robertson, B. W.; Adenwalla, S.

    2007-03-01

    The properties of thin insulator layers are crucial to the performance of magnetic tunnel junctions. Commercial requirements are a device with a high tunnel magnetoresistance (TMR) with low cost and high stability. At present the vast majority of barriers are made from amorphous Al2O3 and crystalline MgO. The TMR value depends not only on the spin-dependent electronic structure of the electrodes, but on the metal-insulator interface. Oxide-type barriers may suffer from local vacancies and other type of defects, resulting in oxygen diffusion, making the TMR value unstable with time. We present TMR results obtained on a non-oxide barrier, boron carbide (B10C2) for applications in magnetic tunnel junctions. This low Z inorganic material can be grown by plasma enhanced chemical vapor deposition (PECVD) without pinholes in the ultra thin film regime. PECVD grown boron carbide is an excellent dielectric with resistivities in the range of 10^7 ohm-cm, with a band gap that can be adjusted from 0.7 eV to 1.9 eV by altering the boron to carbon ratio and to band gap values well above 2.7 eV by adding phosphorus. This creates a unique opportunity for experimental study of a broad spectrum of phenomena, related to the dielectric properties of the barrier.

  9. The Sinai triple junction revisited

    NASA Astrophysics Data System (ADS)

    Courtillot, Vincent; Armijo, Rolando; Tapponnier, Paul

    1987-09-01

    This paper is a summary of a more detailed analysis of the kinematics of the Sinai triple junction (Courtillot et al., 1987). Accurate kinematic data are lacking along the Red Sea and they can be supplemented by bathymetric, topographic and geological data pertaining to the three arms of the entirely continental Sinai triple junction. Motions across the northern Red Sea and along the Gulf of Elat are an order of magnitude larger than across the Gulf of Suez. The direction of motion there remains a major uncertainty. A possible kinematic model is highlighted, in which right-lateral strike-slip motion and small pull-apart basins occur along the Gulf of Suez, in agreement with recent field observations in Egypt. Early Miocene is marked by major geodynamical changes all along the northern boundaries of the African and Indian plates. We suggest that rifting in the Arabian Sea, Gulf of Aden, Red Sea and Gulf of Suez was initiated at the end of the first phase of continental extrusion of Indochina, when the Tibetan plateau began to rise and spreading in the South China Sea came to a halt.

  10. Electron transport through molecular junctions

    NASA Astrophysics Data System (ADS)

    Zimbovskaya, Natalya A.; Pederson, Mark R.

    2011-12-01

    At present, metal-molecular tunnel junctions are recognized as important active elements in molecular electronics. This gives a strong motivation to explore physical mechanisms controlling electron transport through molecules. In the last two decades, an unceasing progress in both experimental and theoretical studies of molecular conductance has been demonstrated. In the present work we give an overview of theoretical methods used to analyze the transport properties of metal-molecular junctions as well as some relevant experiments and applications. After a brief general description of the electron transport through molecules we introduce a Hamiltonian which can be used to analyze electron-electron, electron-phonon and spin-orbit interactions. Then we turn to description of the commonly used transport theory formalisms including the nonequilibrium Green’s functions based approach and the approach based on the “master” equations. We discuss the most important effects which could be manifested through molecules in electron transport phenomena such as Coulomb, spin and Frank-Condon blockades, Kondo peak in the molecular conductance, negative differential resistance and some others. Bearing in mind that first principles electronic structure calculations are recognized as the indispensable basis of the theory of electron transport through molecules, we briefly discuss the main equations and some relevant applications of the density functional theory which presently is often used to analyze important characteristics of molecules and molecular clusters. Finally, we discuss some kinds of nanoelectronic devices built using molecules and similar systems such as carbon nanotubes, various nanowires and quantum dots.

  11. Dermal eosinophilic infiltrate in junctional epidermolysis bullosa.

    PubMed

    Saraiya, Ami; Yang, Catherine S; Kim, Jinah; Bercovitch, Lionel; Robinson-Bostom, Leslie; Telang, Gladys

    2015-08-01

    Junctional epidermolysis bullosa (JEB) is a rare genodermatosis characterized by a split in the lamina lucida usually because of mutations in LAMA3, LAMB3 and LAMC2 resulting in absence or reduction of laminin-332. Rare subtypes of JEB have mutations in COL17A1, ITGB4, ITGA6 and ITGA3 leading to reduction or dysfunction of collagen XVII, integrin α6β4 and integrin α3. The classic finding under light microscopy is a paucicellular, subepidermal split. We describe the unusual presence of an eosinophilic infiltrate in the bullae and subjacent dermis in a neonate with JEB, generalized intermediate (formerly known as non-Herlitz-type JEB), discuss the histologic differential diagnosis for a subepidermal blister in a neonate, review the literature regarding cases of epidermolysis bullosa (EB) presenting with inflammatory infiltrates, and discuss mechanisms to explain these findings. This case highlights that eosinophils can rarely be seen in EB and should not mislead the dermatopathologist into diagnosing an autoimmune blistering disorder. PMID:25950805

  12. Diencephalic–mesencephalic junction dysplasia: a novel recessive brain malformation

    PubMed Central

    Saleem, Sahar N.; Dobyns, William B.; Barkovich, A. James; Bartsch, Hauke; Dale, Anders M.; Ashtari, Manzar; Akizu, Naiara; Gleeson, Joseph G.; Grijalvo-Perez, Ana Maria

    2012-01-01

    We describe six cases from three unrelated consanguineous Egyptian families with a novel characteristic brain malformation at the level of the diencephalic–mesencephalic junction. Brain magnetic resonance imaging demonstrated a dysplasia of the diencephalic–mesencephalic junction with a characteristic ‘butterfly’-like contour of the midbrain on axial sections. Additional imaging features included variable degrees of supratentorial ventricular dilatation and hypoplasia to complete agenesis of the corpus callosum. Diffusion tensor imaging showed diffuse hypomyelination and lack of an identifiable corticospinal tract. All patients displayed severe cognitive impairment, post-natal progressive microcephaly, axial hypotonia, spastic quadriparesis and seizures. Autistic features were noted in older cases. Talipes equinovarus, non-obstructive cardiomyopathy and persistent hyperplastic primary vitreous were additional findings in two families. One of the patients required shunting for hydrocephalus; however, this yielded no change in ventricular size suggestive of dysplasia rather than obstruction. We propose the term ‘diencephalic–mesencephalic junction dysplasia’ to characterize this autosomal recessive malformation. PMID:22822038

  13. Determination of the dissipation in superconducting Josephson junctions

    SciTech Connect

    Mugnai, D. Ranfagni, A.; Cacciari, I.

    2015-02-07

    The results relative to macroscopic quantum tunneling rate, out of the metastable state of Josephson junctions, are examined in view of determining the effect of dissipation. We adopt a simple criterion in accordance to which the effect of dissipation can be evaluated by analyzing the shortening of the semiclassical traversal time of the barrier. In almost all the considered cases, especially those with relatively large capacitance values, the relative time shortening turns out to be about 20% and with a corresponding quality factor Q ≃ 5.5. However, beyond the specific cases here considered, still in the regime of moderate dissipation, the method is applicable also to different situations with different values of the quality factor. The method allows, within the error limits, for a reliable determination of the load resistance R{sub L}, the less accessible quantity in the framework of the resistively and capacitively shunted junction model, provided that the characteristics of the junction (intrinsic capacitance, critical current, and the ratio of the bias current to the critical one) are known with sufficient accuracy.

  14. Low-high junction theory applied to solar cells

    NASA Technical Reports Server (NTRS)

    Godlewski, M. P.; Baraona, C. R.; Brandhorst, H. W., Jr.

    1973-01-01

    Recent use of alloying techniques for rear contact formation has yielded a new kind of silicon solar cell, the back surface field (BSF) cell, with abnormally high open circuit voltage and improved radiation resistance. Several analytical models for open circuit voltage based on the reverse saturation current are formulated to explain these observations. The zero SRV case of the conventional cell model, the drift field model, and the low-high junction (LHJ) model can predict the experimental trends. The LHJ model applies the theory of the low-high junction and is considered to reflect a more realistic view of cell fabrication. This model can predict the experimental trends observed for BSF cells. Detailed descriptions and derivations for the models are included. The correspondences between them are discussed. This modeling suggests that the meaning of minority carrier diffusion length measured in BSF cells be reexamined.

  15. Low-high junction theory applied to solar cells

    NASA Technical Reports Server (NTRS)

    Godlewski, M. P.; Baraona, C. R.; Brandhorst, H. W., Jr.

    1974-01-01

    Recent use of alloying techniques for rear contact formation has yielded a new kind of silicon solar cell, the back surface field (BSF) cell, with abnormally high open-circuit voltage and improved radiation resistance. Several analytical models for open-circuit voltage based on the reverse saturation current are formulated to explain these observations. The zero surface recombination velocity (SRV) case of the conventional cell model, the drift field model, and the low-high junction (LHJ) model can predict the experimental trends. The LHJ model applies the theory of the low-high junction and is considered to reflect a more realistic view of cell fabrication. This model can predict the experimental trends observed for BSF cells.

  16. Josephson junctions with tunable current-phase relation

    NASA Astrophysics Data System (ADS)

    Lipman, A.; Mints, R. G.; Kleiner, R.; Koelle, D.; Goldobin, E.

    2014-11-01

    We consider 0-π Josephson junctions consisting of 0 and π regions of lengths L0 and Lπ with critical current densities jc 0 and jc π, respectively. The dependence of the Josephson current on the phase-shift averaged along the junction is derived. We show that these systems exhibit the main features of φ Josephson junctions—the ground state is doubly degenerate and the current-phase relation can be tuned in situ by applying magnetic field. In the limit of short and long 0 and π regions, the current phase relation is derived analytically. In the case of intermediate lengths of 0 and π regions, the current-phase relation is calculated numerically.

  17. First-principles study of interface doping in ferroelectric junctions

    PubMed Central

    Wang, Pin-Zhi; Cai, Tian-Yi; Ju, Sheng; Wu, Yin-Zhong

    2016-01-01

    Effect of atomic monolayer insertion on the performance of ferroelectric tunneling junction is investigated in SrRuO3/BaTiO3/SrRuO3 heterostrucutures. Based on first-principles calculations, the atomic displacement, orbital occupancy, and ferroelectric polarization are studied. It is found that the ferroelectricity is enhanced when a (AlO2)− monolayer is inserted between the electrode SRO and the barrier BTO, where the relatively high mobility of doped holes effectively screen ferroelectric polarization. On the other hand, for the case of (LaO)+ inserted layer, the doped electrons resides at the both sides of middle ferroelectric barrier, making the ferroelectricity unfavorable. Our findings provide an alternative avenue to improve the performance of ferroelectric tunneling junctions. PMID:27063704

  18. Surface and implantation effects on p-n junctions

    NASA Technical Reports Server (NTRS)

    Schacham, Samuel E.; Finkman, Eliezer

    1990-01-01

    The contribution of the graded region of implanted p-n junctions is analyzed using an exponential profile. Though previously neglected, it was recently shown that this contribution to the saturation current of HgCdTe diodes is significant. Assuming a dominant Auger recombination, an analytical solution to the continuity equation is obtained. An expression for the current generation by the graded region is presented for both ohmic and reflecting boundary conditions. A revised condition for a wide region is derived. When the region is narrow, the current differs drastically from that of the zero-gradient case. The effects of the junction depth and the substrate and surface concentrations on the current are investigated. It is shown that the reverse current does not saturate.

  19. Discovery of a photoresponse amplification mechanism in compensated PN junctions

    SciTech Connect

    Zhou, Yuchun; Rahman, Samia N.; Hall, David; Lo, Yu-Hwa; Liu, Yu-Hsin; Sham, L. J.

    2015-01-19

    We report the experimental evidence of uncovering a photoresponse amplification mechanism in heavily doped, partially compensated silicon p-n junctions under very low bias voltage. We show that the observed photocurrent gain occurs at a bias that is more than an order of magnitude below the threshold voltage for conventional impact ionization. Moreover, contrary to the case of avalanche detectors and p-i-n diodes, the amplified photoresponse is enhanced rather than suppressed with increasing temperature. These distinctive characteristics lead us to hypothesize that the inelastic scattering between energetic electrons (holes) and the ionized impurities in the depletion and charge neutral regions of the p-n junction in a cyclic manner plays a significant role in the amplification process. Such an internal signal amplification mechanism, which occurs at much lower bias than impact ionization and favors room temperature over cryogenic temperature, makes it promising for practical device applications.

  20. Robotic surgery for rectosigmoid junction tumor with ovarian metastases

    PubMed Central

    Bedirli, Abdulkadir; Salman, Bulent

    2015-01-01

    Isolated ovarian metastases from colorectal cancer (CRC) are rare disease presenting in approximately 3% of all patients undergoing colorectal resection. Most reports describe an open approach to the disease, but we report a case isolated ovarian metastases from CRC managed completely by robotic technique. A 54-year-old female, with a family history of CRC, was admitted for rectosigmoid junction cancer. Computed tomography scan demonstrated in rectosigmoid tumor and pelvic mass, presumed as teratoma. Robotic surgery discovered a 10-cm encapsulated tumor, attached to the left ovary, with no macroscopic peritoneal involvement. The pathologic diagnosis of the resected pelvic mass, ovarian metastases from CRC. Robotic anterior resection was performed. Operative time was lasted 165 min, considering 25 min for robotic system set up. This is the first report to describe robot-assisted anterior resection and oophorectomy in patient with isolated ovarian metastases from rectosigmoid junction cancer. PMID:25598608

  1. Endoscopic surgery on the thoracolumbar junction of the spine

    PubMed Central

    2009-01-01

    The thoracolumbar junction is the section of the truncal spine most often affected by injuries. Acute instability with structural damage to the anterior load bearing spinal column and post-traumatic deformity represent the most frequent indications for surgery. In the past few years, endoscopic techniques for these indications have partially superseded the open procedures, which are associated with high access morbidity. The particular position of this section of the spine, which lies in the border area between the thoracic and abdominal cavities, makes it necessary in most cases to partially detach the diaphragm endoscopically in order to expose the operation site, and this also provides access to the retroperitoneal section of the thoracolumbar junction. A now standardised operating technique and instruments and implants specially developed for the endoscopic procedure, from angle stable plate and screw implants to endoscopically implantable vertebral body replacements, have gradually opened up the entire spectrum of anterior spine surgery to endoscopic techniques. PMID:19693549

  2. Living kidney donation following nephrectomy due to pelviureteric junction obstruction.

    PubMed

    Soukup, Benjamin; Vaidya, Anil; Cranston, David

    2015-01-01

    A 49-year-old man presented with a 15-year history of problematic pelviureteric junction obstruction of his left kidney. Surgical management had failed to sufficiently control his symptoms and he was keen to have the kidney removed. Following preoperative discussion, the patient consented to his kidney being used for transplant. Following a total nephrectomy, the kidney was successfully transplanted into a 61-year-old woman, with a cold ischaemic time of 3 h and 22 min. There was primary function in the transplanted kidney and creatinine at 6 weeks was 60. This case highlights the potential for using organs with pelviureteric junction obstruction for living donor transplant and thereby expanding the donor pool. PMID:26002670

  3. Inhibiting Klein Tunneling in a Graphene p -n Junction without an External Magnetic Field

    NASA Astrophysics Data System (ADS)

    Oh, Hyungju; Coh, Sinisa; Son, Young-Woo; Cohen, Marvin L.

    2016-07-01

    We study by first-principles calculations a densely packed island of organic molecules (F4TCNQ ) adsorbed on graphene. We find that with electron doping the island naturally forms a p -n junction in the graphene sheet. For example, a doping level of ˜3 ×1013 electrons per cm2 results in a p -n junction with an 800 meV electrostatic potential barrier. Unlike in a conventional p -n junction in graphene, in the case of the junction formed by an adsorbed organic molecular island we expect that the Klein tunneling is inhibited, even without an applied external magnetic field. Here Klein tunneling is inhibited by the ferromagnetic order that spontaneously occurs in the molecular island upon doping. We estimate that the magnetic barrier in the graphene sheet is around 10 mT.

  4. Inhibiting Klein Tunneling in a Graphene p-n Junction without an External Magnetic Field.

    PubMed

    Oh, Hyungju; Coh, Sinisa; Son, Young-Woo; Cohen, Marvin L

    2016-07-01

    We study by first-principles calculations a densely packed island of organic molecules (F_{4}TCNQ) adsorbed on graphene. We find that with electron doping the island naturally forms a p-n junction in the graphene sheet. For example, a doping level of ∼3×10^{13}  electrons per cm^{2} results in a p-n junction with an 800 meV electrostatic potential barrier. Unlike in a conventional p-n junction in graphene, in the case of the junction formed by an adsorbed organic molecular island we expect that the Klein tunneling is inhibited, even without an applied external magnetic field. Here Klein tunneling is inhibited by the ferromagnetic order that spontaneously occurs in the molecular island upon doping. We estimate that the magnetic barrier in the graphene sheet is around 10 mT. PMID:27419583

  5. Edge mixing dynamics in graphene p-n junctions in the quantum Hall regime

    NASA Astrophysics Data System (ADS)

    Matsuo, Sadashige; Takeshita, Shunpei; Tanaka, Takahiro; Nakaharai, Shu; Tsukagoshi, Kazuhito; Moriyama, Takahiro; Ono, Teruo; Kobayashi, Kensuke

    2015-09-01

    Massless Dirac electron systems such as graphene exhibit a distinct half-integer quantum Hall effect, and in the bipolar transport regime co-propagating edge states along the p-n junction are realized. Additionally, these edge states are uniformly mixed at the junction, which makes it a unique structure to partition electrons in these edge states. Although many experimental works have addressed this issue, the microscopic dynamics of electron partition in this peculiar structure remains unclear. Here we performed shot-noise measurements on the junction in the quantum Hall regime as well as at zero magnetic field. We found that, in sharp contrast with the zero-field case, the shot noise in the quantum Hall regime is finite in the bipolar regime, but is strongly suppressed in the unipolar regime. Our observation is consistent with the theoretical prediction and gives microscopic evidence that the edge states are uniquely mixed along the p-n junction.

  6. Edge mixing dynamics in graphene p–n junctions in the quantum Hall regime

    PubMed Central

    Matsuo, Sadashige; Takeshita, Shunpei; Tanaka, Takahiro; Nakaharai, Shu; Tsukagoshi, Kazuhito; Moriyama, Takahiro; Ono, Teruo; Kobayashi, Kensuke

    2015-01-01

    Massless Dirac electron systems such as graphene exhibit a distinct half-integer quantum Hall effect, and in the bipolar transport regime co-propagating edge states along the p–n junction are realized. Additionally, these edge states are uniformly mixed at the junction, which makes it a unique structure to partition electrons in these edge states. Although many experimental works have addressed this issue, the microscopic dynamics of electron partition in this peculiar structure remains unclear. Here we performed shot-noise measurements on the junction in the quantum Hall regime as well as at zero magnetic field. We found that, in sharp contrast with the zero-field case, the shot noise in the quantum Hall regime is finite in the bipolar regime, but is strongly suppressed in the unipolar regime. Our observation is consistent with the theoretical prediction and gives microscopic evidence that the edge states are uniquely mixed along the p–n junction. PMID:26337445

  7. The tight junction: a multifunctional complex.

    PubMed

    Schneeberger, Eveline E; Lynch, Robert D

    2004-06-01

    Multicellular organisms are separated from the external environment by a layer of epithelial cells whose integrity is maintained by intercellular junctional complexes composed of tight junctions, adherens junctions, and desmosomes, whereas gap junctions provide for intercellular communication. The aim of this review is to present an updated overview of recent developments in the area of tight junction biology. In a relatively short time, our knowledge of the tight junction has evolved from a relatively simple view of it being a permeability barrier in the paracellular space and a fence in the plane of the plasma membrane to one of it acting as a multicomponent, multifunctional complex that is involved in regulating numerous and diverse cell functions. A group of integral membrane proteins-occludin, claudins, and junction adhesion molecules-interact with an increasingly complex array of tight junction plaque proteins not only to regulate paracellular solute and water flux but also to integrate such diverse processes as gene transcription, tumor suppression, cell proliferation, and cell polarity. PMID:15151915

  8. Solar Cells With Multiple Small Junctions

    NASA Technical Reports Server (NTRS)

    Daud, T.; Koliwad, K. M.

    1985-01-01

    Concept for improving efficiency of photovoltaic solar cells based on decreasing p/n junction area in relation to total surface area of cell. Because of reduced junction area, surface leakage drops and saturation current density decreases. Surface passivation helps to ensure short-circuit current remains at high value and response of cells to blue light increases.

  9. Bilateral multicystic renal dysplasia with potter sequence. A case with penile agenesis.

    PubMed

    Dursun, Ahmet; Ermis, Bahri; Numanoglu, Varim; Bahadir, Burak; Seckiner, Ilker

    2006-11-01

    Hereditary renal adysplasia (HRA) is a rare autosomal dominant condition. Patients have several other anomalies including Potter facies, thoracic, cardiac, and extremity deformities. The case present dysmorphic facial features such as hypertelorism, prominent epicanthic folds, a flat and broad nose, choanal stenosis, low-set ears, and a receding chin. He had femoral bowing, hypoplastic right tibia and agenesis of the right foot. He had rich and thick skin. He had also a dysplastic empty scrotum, penile agenesis, and anal atresia. The autopsy revealed pulmonary hypoplasia, ventricular septal defect, bilateral multicystic renal dysplasia, agenesis of both ureter and bladder, intraabdominal testicles, and a single umbilical artery. The penile agenesis was first reported, and including the consanguinity in the parents might further delineate the bilateral multicystic HRA. Vater/caudal regression anomalies, Mullerian duct/aplasia, unilateral renal agenesis, and cervicothoracic somite anomalies association, and Coloboma, heart anomaly, choanal atresia, retardation, genital and ear anomalies syndrome has been considered in differential diagnosis. PMID:17106555

  10. Zipper and freeway shear zone junctions

    NASA Astrophysics Data System (ADS)

    Passchier, Cees; Platt, John

    2016-04-01

    Ductile shear zones are usually presented as isolated planar high-strain domains in a less deformed wall rock, characterised by shear sense indicators such as characteristic deflected foliation traces. Many shear zones, however, form branched systems and if movement on such branches is contemporaneous, the resulting geometry can be complicated and lead to unusual fabric geometries in the wall rock. For Y-shaped shear zone junctions with three simultaneously operating branches, and with slip directions at a high angle to the branch line, eight basic types of shear zone triple junctions are possible, divided into three groups. The simplest type, called freeway junctions, have similar shear sense on all three branches. If shear sense is different on the three branches, this can lead to space problems. Some of these junctions have shear zone branches that join to form a single branch, named zipper junctions, or a single shear zone which splits to form two, known as wedge junctions. Closing zipper junctions are most unusual, since they form a non-active high-strain zone with opposite deflection of foliations. Shear zipper and shear wedge junctions have two shear zones with similar shear sense, and one with the opposite sense. All categories of shear zone junctions show characteristic flow patterns in the shear zone and its wall rock. Shear zone junctions with slip directions normal to the branch line can easily be studied, since ideal sections of shear sense indicators lie in the plane normal to the shear zone branches and the branch line. Expanding the model to allow slip oblique and parallel to the branch line in a full 3D setting gives rise to a large number of geometries in three main groups. Slip directions can be parallel on all branches but oblique to the branch line: two slip directions can be parallel and a third oblique, or all three branches can have slip in different directions. Such more complex shear zone junctions cannot be studied to advantage in a

  11. Ureteropelvic junction obstruction and renal cell carcinoma in a patient with solitary functioning kidney

    PubMed Central

    Jeong, Young Beom; Ko, Oh Seok; Park, Hyung Sub; Cha, Jai Seong; Park, Seung Chol; Kim, Hyung Jin; Park, Jong Kwan; Shin, Yu Seob

    2016-01-01

    We present a case of ureteropelvic junction obstruction (UPJO) and renal cell carcinoma (RCC) in a solitary functioning kidney (SFK), managed by robot-assisted dismembered pyeloplasty with partial nephrectomy in a single stage. To our best knowledge, we report the first case of UPJO with RCC in a congenital SFK. PMID:27330578

  12. Design of immobile nucleic acid junctions.

    PubMed Central

    Seeman, N C; Kallenbach, N R

    1983-01-01

    Nucleic acids that interact to generate structures in which three or more double helices emanate from a single point are said to form a junction. Such structures arise naturally as intermediates in DNA replication and recombination. It has been proposed that stable junctions can be created by synthesizing sets of oligonucleotides of defined sequence that can associate by maximizing Watson-Crick complementarity (Seeman N. C., 1981, Biomolecular Stereodynamics. Adenine Press, New York. 1: 269-278; Seeman, N. C., 1982, J. Theor. Biol. 99:237-247.) To make it possible to design molecules that will form junctions of specific architecture, we present here an efficient algorithm for generating nucleic acid sequences that optimize two fundamental properties: fidelity and stability. Fidelity refers to the relative probability of forming the junction complex relative to all alternative paired structures. Calculations are described that permit approximate prediction of the melting curves for junction complexes. PMID:6197102

  13. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    SciTech Connect

    Cleland, A.N.

    1991-04-01

    Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q {approx} 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement.

  14. Electric field breakdown in single molecule junctions.

    PubMed

    Li, Haixing; Su, Timothy A; Zhang, Vivian; Steigerwald, Michael L; Nuckolls, Colin; Venkataraman, Latha

    2015-04-22

    Here we study the stability and rupture of molecular junctions under high voltage bias at the single molecule/single bond level using the scanning tunneling microscope-based break-junction technique. We synthesize carbon-, silicon-, and germanium-based molecular wires terminated by aurophilic linker groups and study how the molecular backbone and linker group affect the probability of voltage-induced junction rupture. First, we find that junctions formed with covalent S-Au bonds are robust under high voltage and their rupture does not demonstrate bias dependence within our bias range. In contrast, junctions formed through donor-acceptor bonds rupture more frequently, and their rupture probability demonstrates a strong bias dependence. Moreover, we find that the junction rupture probability increases significantly above ∼1 V in junctions formed from methylthiol-terminated disilanes and digermanes, indicating a voltage-induced rupture of individual Si-Si and Ge-Ge bonds. Finally, we compare the rupture probabilities of the thiol-terminated silane derivatives containing Si-Si, Si-C, and Si-O bonds and find that Si-C backbones have higher probabilities of sustaining the highest voltage. These results establish a new method for studying electric field breakdown phenomena at the single molecule level. PMID:25675085

  15. Electrostatic control of thermoelectricity in molecular junctions.

    PubMed

    Kim, Youngsang; Jeong, Wonho; Kim, Kyeongtae; Lee, Woochul; Reddy, Pramod

    2014-11-01

    Molecular junctions hold significant promise for efficient and high-power-output thermoelectric energy conversion. Recent experiments have probed the thermoelectric properties of molecular junctions. However, electrostatic control of thermoelectric properties via a gate electrode has not been possible due to technical challenges in creating temperature differentials in three-terminal devices. Here, we show that extremely large temperature gradients (exceeding 1 × 10(9) K m(-1)) can be established in nanoscale gaps bridged by molecules, while simultaneously controlling their electronic structure via a gate electrode. Using this platform, we study prototypical Au-biphenyl-4,4'-dithiol-Au and Au-fullerene-Au junctions to demonstrate that the Seebeck coefficient and the electrical conductance of molecular junctions can be simultaneously increased by electrostatic control. Moreover, from our studies of fullerene junctions, we show that thermoelectric properties can be significantly enhanced when the dominant transport orbital is located close to the chemical potential (Fermi level) of the electrodes. These results illustrate the intimate relationship between the thermoelectric properties and charge transmission characteristics of molecular junctions and should enable systematic exploration of the recent computational predictions that promise extremely efficient thermoelectric energy conversion in molecular junctions. PMID:25282046

  16. Invariant submanifold for series arrays of Josephson junctions

    NASA Astrophysics Data System (ADS)

    Marvel, Seth A.; Strogatz, Steven H.

    2009-03-01

    We study the nonlinear dynamics of series arrays of Josephson junctions in the large-N limit, where N is the number of junctions in the array. The junctions are assumed to be identical, overdamped, driven by a constant bias current, and globally coupled through a common load. Previous simulations of such arrays revealed that their dynamics are remarkably simple, hinting at the presence of some hidden symmetry or other structure. These observations were later explained by the discovery of N -3 constants of motion, the choice of which confines the resulting flow in phase space to a low-dimensional invariant manifold. Here we show that the dimensionality can be reduced further by restricting attention to a special family of states recently identified by Ott and Antonsen. In geometric terms, the Ott-Antonsen ansatz corresponds to an invariant submanifold of dimension one less than that found earlier. We derive and analyze the flow on this submanifold for two special cases: an array with purely resistive loading and another with resistive-inductive-capacitive loading. Our results recover (and in some instances improve) earlier findings based on linearization arguments.

  17. Coherently driven, ultrafast electron-phonon dynamics in transport junctions

    SciTech Connect

    Szekely, Joshua E.; Seideman, Tamar

    2014-07-28

    Although the vast majority of studies of transport via molecular-scale heterojunctions have been conducted in the (static) energy domain, experiments are currently beginning to apply time domain approaches to the nanoscale transport problem, combining spatial with temporal resolution. It is thus an opportune time for theory to develop models to explore both new phenomena in, and new potential applications of, time-domain, coherently driven molecular electronics. In this work, we study the interaction of a molecular phonon with an electronic wavepacket transmitted via a conductance junction within a time-domain model that treats the electron and phonon on equal footing and spans the weak to strong electron-phonon coupling strengths. We explore interference between two coherent energy pathways in the electronic subspace, thus complementing previous studies of coherent phenomena in conduction junctions, where the stationary framework was used to study interference between spatial pathways. Our model provides new insights into phase decoherence and population relaxation within the electronic subspace, which have been conventionally treated by density matrix approaches that often rely on phenomenological parameters. Although the specific case of a transport junction is explored, our results are general, applying also to other instances of coupled electron-phonon systems.

  18. Plasticity of single-atom Pb junctions

    NASA Astrophysics Data System (ADS)

    Müller, M.; Salgado, C.; Néel, N.; Palacios, J. J.; Kröger, J.

    2016-06-01

    A low-temperature scanning tunneling microscope was used to fabricate atomic contacts on Pb(111). Conductance characteristics of the junctions were simultaneously recorded with forming and subsequent breaking of the contacts. A pronounced hysteresis effect in conductance traces was observed from junctions comprising the clean Pb(111) surface. The hysteretic behavior was less profound in contacts to single Pb atoms adsorbed to Pb(111). Density-functional calculations reproduced the experimental results by performing a full ab initio modeling of plastic junction deformations. A comprehensive description of the experimental findings was achieved by considering different atomic tip apex geometries.

  19. Graded junction termination extensions for electronic devices

    NASA Technical Reports Server (NTRS)

    Merrett, J. Neil (Inventor); Isaacs-Smith, Tamara (Inventor); Sheridan, David C. (Inventor); Williams, John R. (Inventor)

    2007-01-01

    A graded junction termination extension in a silicon carbide (SiC) semiconductor device and method of its fabrication using ion implementation techniques is provided for high power devices. The properties of silicon carbide (SiC) make this wide band gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc. These devices require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power handling capabilities. The graded junction termination extension disclosed is effective, self-aligned, and simplifies the implementation process.

  20. The myoendothelial junction: breaking through the matrix?

    PubMed Central

    Heberlein, Katherine; Straub, Adam; Isakson, Brant E

    2009-01-01

    Within the vasculature, specialized cellular extensions from endothelium (and sometimes smooth muscle) protrude through the extracellular matrix where they interact with the opposing cell type. These structures, termed myoendothelial junctions, have been cited as a possible key element in the control of several vascular physiologies and pathologies. This review will discuss observations that have led to a focus on the myoendothelial junction as a cellular integration point in the vasculature for both homeostatic and pathological conditions and as a possible independent signaling entity. We will also highlight the need for novel approaches to studying the myoendothelial junction in order to comprehend the cellular biology associated with this structure. PMID:19330678

  1. Temperature dependence of thermopower in molecular junctions

    NASA Astrophysics Data System (ADS)

    Kim, Youngsang; Lenert, Andrej; Meyhofer, Edgar; Reddy, Pramod

    2016-07-01

    The thermoelectric properties of molecular junctions are of considerable interest due to their promise for efficient energy conversion. While the dependence of thermoelectric properties of junctions on molecular structure has been recently studied, their temperature dependence remains unexplored. Using a custom built variable temperature scanning tunneling microscope, we measured the thermopower and electrical conductance of individual benzenedithiol junctions over a range of temperatures (100 K-300 K). We find that while the electrical conductance is independent of temperature, the thermopower increases linearly with temperature, confirming the predictions of the Landauer theory.

  2. Palladium electrodes for molecular tunnel junctions.

    PubMed

    Chang, Shuai; Sen, Suman; Zhang, Peiming; Gyarfas, Brett; Ashcroft, Brian; Lefkowitz, Steven; Peng, Hongbo; Lindsay, Stuart

    2012-10-26

    Gold has been the metal of choice for research on molecular tunneling junctions, but it is incompatible with complementary metal-oxide-semiconductor fabrication because it forms deep level traps in silicon. Palladium electrodes do not contaminate silicon, and also give higher tunnel current signals in the molecular tunnel junctions that we have studied. The result is cleaner signals in a recognition-tunneling junction that recognizes the four natural DNA bases as well as 5-methyl cytosine, with no spurious background signals. More than 75% of all the recorded signal peaks indicate the base correctly. PMID:23037952

  3. Graded junction termination extensions for electronic devices

    NASA Technical Reports Server (NTRS)

    Merrett, J. Neil (Inventor); Isaacs-Smith, Tamara (Inventor); Sheridan, David C. (Inventor); Williams, John R. (Inventor)

    2006-01-01

    A graded junction termination extension in a silicon carbide (SiC) semiconductor device and method of its fabrication using ion implementation techniques is provided for high power devices. The properties of silicon carbide (SiC) make this wide band gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc. These devices require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power handling capabilities. The graded junction termination extension disclosed is effective, self-aligned, and simplifies the implementation process.

  4. Differences in expression of junctional adhesion molecule-A and beta-catenin in multiple sclerosis brain tissue: increasing evidence for the role of tight junction pathology.

    PubMed

    Padden, Maureen; Leech, Susie; Craig, Beverly; Kirk, John; Brankin, Brenda; McQuaid, Stephen

    2007-02-01

    Previously we have employed antibodies to the tight junction (TJ)-associated proteins ZO-1 and occludin to describe endothelial tight junction abnormalities, in lesional and normal appearing white matter, in primary and secondary progressive multiple sclerosis (MS). This work is extended here by use of antibodies to the independent TJ-specific proteins and junctional adhesion molecule A & B (JAM-A, JAM-B). We have also assessed the expression in MS of beta-catenin, a protein specific to the TJ-associated adherens junction. Immunocytochemistry and semiquantitative confocal microscopy for JAM-A and beta-catenin was performed on snap-frozen sections from MS cases (n=11) and controls (n=6). Data on 1,443 blood vessels was acquired from active lesions (n=13), inactive lesions (n=13), NAWM (n=20) and control white matter (n=13). In MS abnormal JAM-A expression was found in active (46%) and inactive lesions (21%), comparable to previous data using ZO-1. However, a lower level of TJ abnormality was found in MS NAWM using JAM-A (3%) compared to ZO-1 (13%). JAM-B was strongly expressed on a small number of large blood vessels in control and MS tissues but at too low a level for quantitative analysis. By comparison with the high levels of abnormality observed with the TJ proteins, the adherens junction protein beta-catenin was normally expressed in all MS and control tissue categories. These results confirm, by use of the independent marker JAM-A, that TJ abnormalities are most frequent in active white matter lesions. Altered expression of JAM-A, in addition to affecting junctional tightness may also both reflect and affect leukocyte trafficking, with implications for immune status within the diseased CNS. Conversely, the adherens junction component of the TJ, as indicated by beta-catenin expression is normally expressed in all MS and control tissue categories. PMID:17024496

  5. Single Molecule Junctions: A Laboratory for Chemistry, Mechanics and Bond Rupture

    SciTech Connect

    Hybertsen M. S.

    2013-07-08

    Simultaneous measurement [1] of junction conductance and sustained force in single molecule junctions bridging metal electrodes provides a powerful tool in the quantitative study of the character of molecule-metal bonds. In this talk I will discuss three topics. First, I will describe chemical trends in link bond strength based on experiments and Density Functional Theory based calculations. Second, I will focus on the specific case of pyridine-linked junctions. Bond rupture from the high conductance junction structure shows a requires a force that exceeds the rupture force of gold point contacts and clearly indicates the role of additional forces, beyond the specific N-Au donor acceptor bond. DFT-D2 calculations with empirical addition of dispersion interactions illustrates the interplay between the donor-acceptor bonding and the non-specific van der Waals interactions between the pyridine rings and Au asperities. Third, I will describe recent efforts to characterize the diversity of junction structures realized in break-junction experiments with suitable models for the potential surfaces that are observed. [1] Venkataraman Group, Columbia University.

  6. Effects of order parameter self-consistency in a s±-s junction

    NASA Astrophysics Data System (ADS)

    Rodríguez-Mota, Rosa; Berg, Erez; Pereg-Barnea, T.

    2016-06-01

    The properties of Josephson tunneling between a single-band s -wave superconductor and a two-band s± superconductor are studied, in relation to recent experiments involving iron-based superconductors. We study both a single junction and a loop consisting of two junctions. In both cases, the relative phase between the order parameters of the two superconductors is tuned and the energy of the system is calculated. In a single junction, we find four types of behaviors characterized by the location of minima in the energy/phase relations. These phases include a newly found double minimum junction, which appears only when the order parameters are treated self-consistently. We analyze the loop geometry setup in light of our results for a single junction, where the phase difference in the junctions is controlled by a threaded flux. We find four types of energy/flux relations. These include states for which the energy is minimized when the threaded flux is an integer or half-integer number of flux quanta, a time reversal broken state and a metastable state.

  7. Effective medium theory of the space-charge region electrostatics of arrays of nanoscale junctions

    NASA Astrophysics Data System (ADS)

    Gurugubelli, Vijaya Kumar; Karmalkar, Shreepad

    2016-01-01

    We develop an Effective Medium Theory for the electrostatics of the Space-Charge Region (SCR) of Schottky and p-n junctions in arrays of nanofilms (NFs), nanowires (NWs), and nanotubes (NTs) in a dielectric ambient. The theory captures the effects of electric fields in both the semiconductor, i.e., NF/NW/NT, and the dielectric media of the array. It shows that the depletion width and the screening length characterizing the SCR tail in the array correspond to those in a bulk junction with an effective semiconductor medium, whose permittivity and doping are their weighted averages over the cross-sectional areas of the semiconductor and dielectric; the shapes of the cross-sections are immaterial. Further, the reverse bias 1 /C2 -V behavior of junctions in NF/NW/NT arrays is linear, as in bulk junctions, and is useful to extract from measurements the built-in potential, effective doping including the semiconductor-dielectric interface charge, and NF/NW/NT length. The theory is validated with numerical simulations, is useful for the experimentalist, and yields simple formulas for nano-device design which predict the following. In the limiting case of a single sheet-like NF, the junction depletion width variation with potential drop is linear rather than square-root (as in a bulk junction). In arrays of symmetric silicon p-n junctions in oxide dielectric where NF/NW thickness and separation are 5% and 100% of the bulk depletion width, respectively, the junction depletion width and the screening length are scaled up from their bulk values by the same factor of ˜2 for NF and ˜10 for NW array.

  8. A Model for the Behavior of Magnetic Tunnel Junctions

    SciTech Connect

    Bryan John Baker

    2003-08-05

    of states function, and has developed an exact analytic solution for the case of an electron band of finite width. The approach taken in this thesis easily allows extension to cases where the band structure is different on either side of the barrier (known as heterojunctions) which are of greater interest in real magnetic tunnel junction devices rather than the simple, identical band structure devices.

  9. Tunnel junction multiple wavelength light-emitting diodes

    DOEpatents

    Olson, J.M.; Kurtz, S.R.

    1992-11-24

    A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect. 5 figs.

  10. Tunnel junction multiple wavelength light-emitting diodes

    DOEpatents

    Olson, Jerry M.; Kurtz, Sarah R.

    1992-01-01

    A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect.