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Sample records for tethered cord syndrome

  1. Tethered Spinal Cord Syndrome

    Science.gov (United States)

    ... SEARCH Definition Treatment Prognosis Clinical Trials Organizations Publications Definition Tethered spinal cord syndrome is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the ...

  2. A Child with Tethered Cord Syndrome

    Directory of Open Access Journals (Sweden)

    Bekti Safarini

    2012-06-01

    Full Text Available Tethered Cord Syndome (TCS refers to a group of neurological disorders related to malformations of the spinal cord, pulling of the spinal cord at the base of spinal canal. Tethered cord syndrome can be seen at any age but most often during childhood. A few children complain of diffuse pain in lower extremitiesor urological symptoms, 20% - 30 % of the patients will have a neurogenic bladder. A 9 years old girl, complained to have a flank pain and eneuresis. A mass is palpable at right flank. Ultrasound revealed duplex hydronephrosis and hydroureter with trabeculated bladder. Voiding Cystouretrography showed grade V vesicoureteral reflux (VUR and neurogenic bladder appearance. Lumbosacral MRI demonstrated tethered cord with adjacent lipoma and spina bifida (Sains Medika, 4(1:89-96.

  3. Tethered Cord Syndrome with Syrinx in A Nigerian Adult Female: A ...

    African Journals Online (AJOL)

    Alasia Datonye

    modern imaging tools like MRI, the diagnosis of TCS is no more as rare as it is ... Keywords: Tethered cord; Syringomyelia; MRI; Adult;. Nigeria. ... DISCUSSION. Tethered cord syndrome (TCS) is a pull-induced functional disease of the spinal cord with its caudal part anchored by an. 3 inelastic structure . Garcean first ...

  4. Tethered cord syndrome with spina bifida aperta in cats: two case reports of different types

    Science.gov (United States)

    Tamura, Masahiro; Oji, Takashi; Une, Satoshi; Mukaino, Makiko; Bekki, Tatsuro; Tado, Masaki; Koyama, Hiromi; Kagawa, Yumiko; Kawata, Mutsumi

    2017-01-01

    Case summary Two castrated male cats, aged 8 months old (case 1) and 10 months old (case 2), showed a history of progressive paraparesis, an over-reaching pelvic limb gait, urinary incontinence and a palpable dermoid fistula. In case 1, the fistula was connected to the dural sac on the conus medullaris, and the tethered spinal cord was retracted caudally. In case 2, the tubular structure was connected to the dural sac on the thoracic spinal cord, and the tethered spinal cord was retracted dorsally. Tethered cord syndrome secondary to spina bifida aperta was suspected in both cats. Excision of the fistula and release of the tethered spinal cord was performed. A histopathological examination confirmed the diagnosis of a meningomyelocele in case 1 and a meningocele in case 2. Paraparesis improved postoperatively in both cats. However, urinary incontinence in case 1 remained partially unresolved. Relevance and novel information This is the first report to describe the imaging characteristics, surgical treatments and outcomes of two different types of tethered cord syndrome with spina bifida aperta in cats. Tethered cord syndrome with spina bifida aperta needs to be included in the differential diagnosis of slowly progressive paraparesis in younger cats with or without vesicorectal failure and a palpable dermoid fistula. PMID:28546867

  5. Tethered cord syndrome with spina bifida aperta in cats: two case reports of different types

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    Masahiro Tamura

    2017-05-01

    Full Text Available Case summary Two castrated male cats, aged 8 months old (case 1 and 10 months old (case 2, showed a history of progressive paraparesis, an over-reaching pelvic limb gait, urinary incontinence and a palpable dermoid fistula. In case 1, the fistula was connected to the dural sac on the conus medullaris, and the tethered spinal cord was retracted caudally. In case 2, the tubular structure was connected to the dural sac on the thoracic spinal cord, and the tethered spinal cord was retracted dorsally. Tethered cord syndrome secondary to spina bifida aperta was suspected in both cats. Excision of the fistula and release of the tethered spinal cord was performed. A histopathological examination confirmed the diagnosis of a meningomyelocele in case 1 and a meningocele in case 2. Paraparesis improved postoperatively in both cats. However, urinary incontinence in case 1 remained partially unresolved. Relevance and novel information This is the first report to describe the imaging characteristics, surgical treatments and outcomes of two different types of tethered cord syndrome with spina bifida aperta in cats. Tethered cord syndrome with spina bifida aperta needs to be included in the differential diagnosis of slowly progressive paraparesis in younger cats with or without vesicorectal failure and a palpable dermoid fistula.

  6. Reduction of caudal traction force using dural sac opening rather than spinal cord detethering for tethered cord syndrome caused by lipomyelomeningocele: a case report.

    Science.gov (United States)

    Murata, Yasuaki; Kanaya, Kohichi; Wada, Hiroyoshi; Wada, Keiji; Shiba, Masahiro; Kato, Yoshiharu

    2014-10-01

    A few reports have addressed tethered cord syndrome. Detethering surgery has been performed in these cases because abnormal tension on the spinal cord causes neurologic and urologic symptoms. To discuss the surgical treatment of tethered cord syndrome with the belief that the tension on the cord can be decreased by shifting tethered cord to the dorsal side. A patient with tethered cord syndrome was surgically treated by shifting the tethered cord to the dorsal side by harnessing the lumbar lordosis instead of detethering. We performed surgery to shift the tethered cord to the dorsal side by harnessing the lumbar lordosis to decrease the tension on the spinal cord. The tethered cord that was pressed to the ventral side because of a lipoma was shifted dorsally by laminectomy and opening of the dural sac. Pain and numbness were alleviated immediately after surgery. The method used in the present case, that is, shifting the tethered cord and lipoma to the dorsal side by harnessing the lumbar lordosis instead of detethering, is a viable treatment option for tethered cord syndrome. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Diagnosis and surgical treatment of terminal syringomyelia within spinal cord combined with tethered cord syndrome

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    Jing-cheng XIE

    2016-04-01

    Full Text Available Objective To summarize the clinical manifestations, imaging characteristics and experience of surgical treatment of spinal cord terminal syringomyelia with tethered cord syndrome (TCS.  Methods and Results Clinical data of 10 patients with spinal cord syringomyelia combined with TCS surgically treated under microscope from January 1999 to March 2014 in our hospital were retrospectively analyzed. There were 3 males and 7 females with average age of 15.06 years old (ranged from 2 to 35 years old. The course of disease ranged from 3 months to 20 years (average 42.17 months. Among those patients, one patient presented hydromyelia, 8 patients suffered from meningeal cyst within the sacral canal, and one patient were concurrent with sacral dermal sinus. The weakness of lower extremities, especially distal limbs, was the main clinical manifestation. Five patients were accompanied with bowel and bladder dysfunction and 5 patients with sensory disturbance below the level of syringomyelia, especially hypesthesia. Preoperative MRI showed conus medullaris disappeared at the end of spinal cord, and there was fluid signal in the lower spinal cord with hypo-intensity signal in T1WI and hyper-intensity signal in T2WI without enhancement. All patients underwent surgical procedures. Under microscope, filum terminale was cut off, drainage was performed, meningeal cyst within the sacral canal was removed, and tethered cord was released. The success rate of operations was 100%. The duration of surgery ranged from 1.52 to 3.07 h (average 2.15 h, with average intraoperative blood loss 220 ml (ranged from 100 to 410 ml. The tethering filum had been totally resected and histological examination showed typical filum tissue in all cases. No operative complication was found. Visual Analogue Scale (VAS score was decreased, and the lower limbs weakness as well as bowel and bladder dysfunction was gradually relieved after operation. The period of follow-up was ranged from 6

  8. Tethered Cord Syndrome with Syrinx in A Nigerian Adult Female: A ...

    African Journals Online (AJOL)

    Alasia Datonye

    system did not show scoliosis. The respiratory and gastrointestinal systems were all normal. There were no cutaneous stigmata (hypertrichosis). Laboratory investigations showed normal haematogical indices. Urinalysis was also normal. An impression of transverse myelitis was made to exclude tethered cord syndrome.

  9. Management of concomitant scoliosis and tethered cord syndrome in non-spina bifida pediatric population.

    Science.gov (United States)

    Yaltırık, Kaan; El Tecle, Najib E; Pierson, Matthew J; Puryear, Aki; Atalay, Basar; Elbabaa, Samer K

    2017-11-01

    The management of concomitant scoliosis and tethered cord syndrome in the non-spina bifida pediatric population is challenging. In the present study, we evaluate the efficacy of different treatment modalities and propose a treatment plan for the management of affected patients. A systematic literature review was conducted by querying the MEDLINE, PubMed, Cochrane, EMBASE, Scopus, and Web of Science databases for papers published between January 1996 and June 2016 and reporting on concomitant scoliosis and tethered cord. We excluded animal studies, non-English papers as well as papers reporting on patients with multiple concomitant intraspinal anomalies such as spina bifida. Out of 1993 articles, only 13 met our inclusion criteria. These 13 articles described six main management approaches: Observation, cord untethering only, cord untethering followed by deformity correction, simultaneous cord untethering and deformity correction, and deformity correction without untethering. Selection of the best approach is a function of the patient's symptomatology and Cobb angle. We propose treatment plan for the management of patients with concomitant tethered cord syndrome and spinal deformity. Asymptomatic patients can be followed conservatively and managed as scoliosis patients with no need for untethering. Surgical management in a staged fashion seems appropriate in symptomatic patients with a Cobb angle less than 35°. In these patients, deformity can improve following untethering, thus sparing the patient the risks of surgical correction of scoliosis. Staged or non-staged cord untethering and curve correction seem to be adequate in symptomatic patients with Cobb angle >35° as these patients are likely to require both untethering and deformity correction.

  10. Association between chromosomal aberration of COX8C and tethered spinal cord syndrome: array-based comparative genomic hybridization analysis

    Directory of Open Access Journals (Sweden)

    Qiu-jiong Zhao

    2016-01-01

    Full Text Available Copy number variations have been found in patients with neural tube abnormalities. In this study, we performed genome-wide screening using high-resolution array-based comparative genomic hybridization in three children with tethered spinal cord syndrome and two healthy parents. Of eight copy number variations, four were non-polymorphic. These non-polymorphic copy number variations were associated with Angelman and Prader-Willi syndromes, and microcephaly. Gene function enrichment analysis revealed that COX8C, a gene associated with metabolic disorders of the nervous system, was located in the copy number variation region of Patient 1. Our results indicate that array-based comparative genomic hybridization can be used to diagnose tethered spinal cord syndrome. Our results may help determine the pathogenesis of tethered spinal cord syndrome and prevent occurrence of this disease.

  11. Tethered Cord Syndrome with Syrinx in A Nigerian Adult Female: A ...

    African Journals Online (AJOL)

    There were no cutaneous stigmata (hypertrichosis). Laboratory investigations showed normal hematological indices. Urinalysis was also normal. An impression of acute transverse myelitis was made. Magnetic resonance imaging showed tethered cord and syrinx in the lumbar region. Conclusion: Tethered cord association ...

  12. [Simultaneous diagnosis of pseudomeningocele, tethered cord syndrome and cerebrospinal fluid fistula: Report of a case].

    Science.gov (United States)

    Quillo-Olvera, Javier; Zambrano-Velarde, Luis E; Velázquez-Santana, Héctor; Gutiérrez-Partida, Carlos F; Velázquez-García, Francisco; Alcántara-Gómez, Leopoldo A

    2016-01-01

    The clinical case is presented on a patient with an extensive sacral dysraphism, a history of myelomeningocele surgical repair in her childhood, as well as tethered cord syndrome. The patient was also diagnosed with pseudomeningocele and a cerebrospinal fluid cutaneous fístula. A surgical approach was used, with encouraging results being obtained in the clinical outcome of the patient. A review of the literature was performed to support the surgical decision in this case. Copyright © 2015 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  13. An Unusual Presentation of Adult Tethered Cord Syndrome Associated with Severe Chest and Upper Back Pain

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    Shotaro Kanda

    2015-01-01

    Full Text Available Adult tethered cord syndrome (ATCS is a rare entity that usually presents with multiple neurological symptoms, including lower extremity pain, backache, lower extremity muscle weakness, and bowel/bladder disturbances. Prompt surgical treatment is often necessary to avoid permanent sequelae. We report a 63-year-old man with sudden-onset severe right chest and upper back pain, followed by urinary retention. His initial workup included computed tomography of the abdomen and pelvis, which showed a presacral mass. His symptom-driven neurological workup focused on the cervical and thoracic spine, the results of which were normal. Pelvic radiographs and magnetic resonance imaging of the lumbosacral spine showed spina bifida occulta, meningocele, and presacral masses consistent with a teratomatous tumor. His symptoms, except for urinary retention, improved dramatically with surgical treatment. The excised specimen contained a teratomatous lesion plus an organized hematoma. Hematoma formation was suspected as the trigger of his sudden-onset right chest and upper back pain.

  14. Currarino syndrome with intramedullary spinal cord abscess related communication between the tethered cord and a presacral mass: A case report

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    Takahiro Jimbo

    2015-10-01

    Full Text Available We herein report the case of a 21-day-old boy in which the detection of an intramedullary spinal cord abscess led to the diagnosis of Currarino syndrome (CS. He had a complete phenotype of CS, including sacral agenesis, an anorectal malformation, a presacral mass, and spinal cord malformations. In addition, he had an intramedullary spinal cord abscess. Intramedullary spinal cord abscess is rare in CS and is thought to require immediate intervention. Therefore, we additionally reviewed the available literature and discussed the therapeutic approach for CS with an intramedullary cord abscess.

  15. Dynamic Lumbosacral Magnetic Resonance Imaging in a Dog with Tethered Cord Syndrome with a Tight Filum Terminale

    Science.gov (United States)

    De Decker, Steven; Watts, Vicky; Neilson, David M.

    2017-01-01

    A 1-year and 11-month- old English Cocker Spaniel was evaluated for clinical signs of progressive right pelvic limb lameness and urinary incontinence. Neurological examination was suggestive of a lesion localized to the L4–S3 spinal cord segments. No abnormalities were seen on magnetic resonance imaging (MRI) performed in the dog in dorsal recumbency and the hips in a neutral position and the conus medullaris ended halfway the vertebral body of L7. An MRI of the hips in extended and flexed positions demonstrated minimal displacement of the conus medullaris in the cranial and caudal directions, respectively. Similar to the images in neutral position, the conus medullaris ended halfway the vertebral body of L7 in both the extended and flexed positions. In comparison, an MRI of the hips in neutral, extended, and flexed positions performed in another English Cocker Spaniel revealed obvious cranial displacement of the conus medullaris with the hips in extension and caudal displacement with hips in flexion. A standard dorsal lumbosacral laminectomy was performed. Visual inspection of the vertebral canal revealed excessive caudal traction on the conus medullaris. After sectioning the distal aspect of the filum terminale, the conus medullaris regained a more cranial position. A neurological examination 4 weeks after surgery revealed clinical improvement. Neurological examinations at 2, 4, 7, and 12 months after surgery did not reveal any abnormalities, and the dog was considered to be clinically normal. Tethered cord syndrome with a tight filum terminale is a very rare congenital anomaly and is characterized by an abnormally short and inelastic filum terminale. Therefore, this disorder is associated with abnormal caudal traction on the spinal cord and decreased physiological craniocaudal movements of the neural structures within the vertebral canal. Although further studies are necessary to evaluate and quantify physiological craniocaudal movement of the spinal cord

  16. Dynamic Lumbosacral Magnetic Resonance Imaging in a Dog with Tethered Cord Syndrome with a Tight Filum Terminale

    Directory of Open Access Journals (Sweden)

    Steven De Decker

    2017-08-01

    Full Text Available A 1-year and 11-month- old English Cocker Spaniel was evaluated for clinical signs of progressive right pelvic limb lameness and urinary incontinence. Neurological examination was suggestive of a lesion localized to the L4–S3 spinal cord segments. No abnormalities were seen on magnetic resonance imaging (MRI performed in the dog in dorsal recumbency and the hips in a neutral position and the conus medullaris ended halfway the vertebral body of L7. An MRI of the hips in extended and flexed positions demonstrated minimal displacement of the conus medullaris in the cranial and caudal directions, respectively. Similar to the images in neutral position, the conus medullaris ended halfway the vertebral body of L7 in both the extended and flexed positions. In comparison, an MRI of the hips in neutral, extended, and flexed positions performed in another English Cocker Spaniel revealed obvious cranial displacement of the conus medullaris with the hips in extension and caudal displacement with hips in flexion. A standard dorsal lumbosacral laminectomy was performed. Visual inspection of the vertebral canal revealed excessive caudal traction on the conus medullaris. After sectioning the distal aspect of the filum terminale, the conus medullaris regained a more cranial position. A neurological examination 4 weeks after surgery revealed clinical improvement. Neurological examinations at 2, 4, 7, and 12 months after surgery did not reveal any abnormalities, and the dog was considered to be clinically normal. Tethered cord syndrome with a tight filum terminale is a very rare congenital anomaly and is characterized by an abnormally short and inelastic filum terminale. Therefore, this disorder is associated with abnormal caudal traction on the spinal cord and decreased physiological craniocaudal movements of the neural structures within the vertebral canal. Although further studies are necessary to evaluate and quantify physiological craniocaudal movement

  17. Tethered spinal cord syndrome with lumbar segmental stenosis treated with XLIF

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    Ettore Carpineta, MD

    2017-09-01

    Conclusion: Literature review of adults TCS associated with lumbar spinal degenerative disease as lumbar canal stenosis or disc herniation, is reported. Moderate entity of traction of spinal cord may remain asymptomatic in childhood and may result in delayed neurological deficits in adult life. The stretching of conus medullaris and spinal nerves of cauda equina, reduces regional blood flow and causes neural death and fibrous tissue replacement. Sudden or progressive onset of paraparesis with spastic gait, bladder dysfunction and acute low back pain in patient with history of spinal dysraphism must be considered as possible lumbar spinal cord compression caused by low lying cord related to TCS. Surgical decompression should be performed as early as possible to ensure neurological recovery. XLIF approach seems to be safe and fast and represent an excellent surgical option to obtain spinal cord indirect decompression and lumbar interbody fusion.

  18. Back to Future Health Blueprint: The Effects of a Brief Bioenergy Economy Program on a Patient with Tethered Cord Syndrome

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    Farzad Goli

    2016-12-01

    Full Text Available Background: The spinal cord congenital abnormalities may prevent normal cephalad movement of the conusmedullaris such as tethered cord. A child or even an adult with these abnormalities may develop progressiveneurological dysfunction due to traction on the cord or nerve roots. As the most problematic technicalconsideration in surgery for the release of the tethered cord is how to preserve functions of neural elementsand rebuild the dural sac to maintain normal cerebrospinal fluid (CSF circulation; the priority is to treat thecondition through less invasive methods. Bioenergy economy (BEE is an integrative healing model which triesto abstract healing modalities and integrate them into a psychosomatic health system. In contrast toreductionistic and pathology-based approach of biomedical treatment, bioenergy healing is a salutogenic,holistic and metadiagnostic approach which creates healing responses from a blueprint of healthy body.Case Report: We report the process of a bioenergy economy intervention in a 10-year-old boy withclinical signs of drop foot, urinary incontinence, urinary reflux, and low back pain who was candidate forsurgeries by neurosurgical and urological criteria. The clinical results indicated that after about two yearsof 12 healing sessions in a brief bioenergy economy package of biofield scanning, biofield attunement,and hand-on self-healing, the patient’s clinical signs remarkably improved to the extent that he returned tonormal activities of his age and followed an athletic lifestyle.Conclusion: From a biosemiotic viewpoint, it can be discussed that bioenergy economy, by focusing onenhancing the pathways of salutogenesis was effective to evoke healing response in the patient’s body.The effect of the bioenergy economy practice may be due to the healing images and intentions flowedthrough patient’s body and healer-healee biofields’ coupling and interactions.

  19. Co-existing spinal intradural ependymal cyst and sacral Tarlov cyst in adult-onset tethered cord syndrome with syringomyelia: Case report and literature review.

    Science.gov (United States)

    Rai, Hamid H; Khan, Muhammad F; Enam, Syed Ather; Hashmi, Imtiaz

    2016-01-01

    Synchronous spinal intradural ependymal cysts and sacral Tarlov cysts in adult onset tethered cord syndrome are extremely rare. A 23-year-old male presented with back pain radiating into both lower extremities, accompanied by acute onset of gait difficulty and sphincter dysfunction. Magnetic resonance imaging identified a low lying conus medullaris, syringomyelia with septations extending from T12 to S1, a tethered cord, and a thickened filum terminale with a sacral Tarlov cyst. The patient underwent a L3-4 laminectomy for decompression of syringomyelia and excision/biopsy of a space occupying lesion along with S1-2 laminectomy for cord untethering and Tarlov cyst fenestration. Postoperative histopathology confirmed that the lesion was an ependymal cyst. Clinically, patient showed marked improvement in the neurological status. Simultaneous decompressive laminectomy of L3-4 and S1-2 effectively decompressed the syringomyelia while allowing for excision/biopsy of a space occupying lesion at the former and untethering and Tarlov cyst fenestration at the latter levels.

  20. Central Cord Syndrome

    Science.gov (United States)

    ... You are here Home » Disorders » All Disorders Central Cord Syndrome Information Page Central Cord Syndrome Information Page What research is being done? Our understanding of central cord syndrome has increased greatly in recent decades as ...

  1. Medullary cone movement in subjects with a normal spinal cord and in patients with a tethered spinal cord

    NARCIS (Netherlands)

    Witkamp, T. D.; Vandertop, W. P.; Beek, F. J.; Notermans, N. C.; Gooskens, R. H.; van Waes, P. F.

    2001-01-01

    To compare movement of the normal medullary cone when the patient has changed from a supine to prone position with that in patients with known or suspected tethered spinal cord syndrome. Fifty-six individuals divided into three groups were examined with lumbar spine magnetic resonance (MR) imaging

  2. Minimally invasive tethered cord release in children: A technical note

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    S. Kağan Başarslan

    2014-03-01

    Full Text Available Tethered cord release is commonly performed in pediatric neurosurgery. Nowadays, minimally invasive procedures are created growing interest due to its highly tolerable nature for surgery. It has been main purpose a minimal damaging on access route and maximum protection of normal structures in surgery. We present a surgical treatment of tethered cord syndrome, by which is provided the cord releasing unlike the many methods being applied with tissue removal. The main advantage of performing this surgery through 2 cm hole is to avoid removing ligamentum flavum and bony structure like lamina in addition to reduce the length of the incision and the related scar tissue. J Clin Exp Invest 2014; 5 (1: 115-117 Technical note: the patient was taken on the operating table in the sitting-prone position, and L5-S1 distance was determined by fluoroscopy. The skin and subcutaneous tissues was passed via a 2 cm vertical incision settled in 0.5 cm laterally from midline. L5-S1 distance and its covering ligamentum flavum are displayed by the guidance of L5 lamina. Williams’s retractor was placed in the distance after fetching microscope. The foregoing procedures are the same with microdiscectomic surgery. By a vertical incision made on the flavum, its both layer was lifted up and hanged with simple suture on the back tissue for a comfortable exposure of the Dura. Thecal sac was opened by 0.5 cm long vertical incision on the Dura after obtaining secure CSF drainage with the help of yellow-tipped syringe needle. With finding by a nerve hook, the phylum was burned and released securely. Then the Dura was sutured primarily for the closure by means of microsurgery instruments, and flavum was laid on it again.

  3. The International Tethered Cord Partnership: Beginnings, process, and status

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    Mulholland, Celene B.; Aranda, Guzmán; Arredondo, Luis Angel; Calgua, Erwin; Contreras, Fernando; Espinoza, Dulce Maria; Gonzalez, Juan Bosco; Hoil, Jose A.; Komolafe, Edward; Lazareff, Jorge A.; Liu, Yunhui; Soto-Mancilla, Juan Luis; Mannucci, Graciela; Nan, Bao; Portillo, Santiago; Zhao, Hongyu

    2011-01-01

    Background: Spina bifida presents a significant cause of childhood morbidity in lower- and middle-income nations. Unfortunately, there is a paucity of literature examining outcomes among children with spina bifida in these countries. The goal of the International Tethered Cord Parternship is twofold: (1) to establish an international surveillance database to examine the correlation between time of repair and clinical outcomes in children with spina bifida and tethered cord; and (2) to foster collaboration among international institutions around pediatric neurosurgical concerns. Methods: Twelve institutions in 7 countries committed to participating in the International Tethered Cord Partnership. A neurosurgeon at each institution will evaluate all children presenting with spina bifida and/or tethered cord using the survey instrument after appropriate consent is obtained. The instrument was developed collaboratively and based on previous measures of motor and sensory function, ambulation, and continence. All institutions who have begun collecting data received appropriate Institutional Review Board approval. All data will be entered into a Health Insurance Portability and Accountability Act (HIPAA) compliant database. In addition, a participant restricted internet forum was created to foster communication and includes non–project-specific communications, such as case and journal article discussion. Results: From October 2010 to December 2010, 82 patients were entered from the various study sites. Conclusion: To our knowledge this is the first international pediatric neurosurgical database focused on clinical outcomes and predictors of disease progression. The collaborative nature of the project will not only increase knowledge of spina bifida and tethered cord, but also foster discussion and further collaboration between neurosurgeons internationally. PMID:21541204

  4. The International Tethered Cord Partnership: Beginnings, process, and status.

    Science.gov (United States)

    Mulholland, Celene B; Aranda, Guzmán; Arredondo, Luis Angel; Calgua, Erwin; Contreras, Fernando; Espinoza, Dulce Maria; Gonzalez, Juan Bosco; Hoil, Jose A; Komolafe, Edward; Lazareff, Jorge A; Liu, Yunhui; Soto-Mancilla, Juan Luis; Mannucci, Graciela; Nan, Bao; Portillo, Santiago; Zhao, Hongyu

    2011-03-23

    Spina bifida presents a significant cause of childhood morbidity in lower- and middle-income nations. Unfortunately, there is a paucity of literature examining outcomes among children with spina bifida in these countries. The goal of the International Tethered Cord Parternship is twofold: (1) to establish an international surveillance database to examine the correlation between time of repair and clinical outcomes in children with spina bifida and tethered cord; and (2) to foster collaboration among international institutions around pediatric neurosurgical concerns. Twelve institutions in 7 countries committed to participating in the International Tethered Cord Partnership. A neurosurgeon at each institution will evaluate all children presenting with spina bifida and/or tethered cord using the survey instrument after appropriate consent is obtained. The instrument was developed collaboratively and based on previous measures of motor and sensory function, ambulation, and continence. All institutions who have begun collecting data received appropriate Institutional Review Board approval. All data will be entered into a Health Insurance Portability and Accountability Act (HIPAA) compliant database. In addition, a participant restricted internet forum was created to foster communication and includes non-project-specific communications, such as case and journal article discussion. From October 2010 to December 2010, 82 patients were entered from the various study sites. To our knowledge this is the first international pediatric neurosurgical database focused on clinical outcomes and predictors of disease progression. The collaborative nature of the project will not only increase knowledge of spina bifida and tethered cord, but also foster discussion and further collaboration between neurosurgeons internationally.

  5. Dorsal Cervical Spinal Cord Herniation Precipitated by Kyphosis Deformity Correction for Spinal Cord Tethering.

    Science.gov (United States)

    Heller, Robert S; Hwang, Steven W; Riesenburger, Ron I

    2017-04-01

    Cervical spinal cord herniation is a rare clinical entity. Reported after previous intradural surgery or surgery complicated by durotomy, patients return several months to years later with symptoms of worsening myelopathy. Herein is presented a case of a 51-year-old female patient with spinal cord herniation in the cervical spine after kyphosis deformity correction. A 51-year old female patient presented to the neurosurgery clinic with worsening cervical myelopathy due to cervical spinal cord tethering and adhesions from previous intradural surgery for Chiari malformation. Conservative treatment initially was recommended but ultimately unsuccessful, as her neurologic function continued to deteriorate. Follow-up imaging demonstrated progressive cervical kyphotic deformity with stability of the tethered spinal cord. The patient underwent cervical deformity correction to reduce tension on the spinal cord, after which her neurologic symptoms stabilized and began to improve with physical therapy. Four months after surgery, she returned to clinic with recurrence of cervical myelopathy. Repeat imaging demonstrated herniation of the cervical spinal cord through a dorsal defect, and the patient was treated successfully with a wide cervical duraplasty to recreate an intact thecal sac. The inability of the spinal cord to compensate for changes in spinal alignment in cases of tethering makes it susceptible to increased pressure and tension at the point of tethering. Caution is urged when attempting deformity correction in the presence of spinal cord tethering, which may limit the capacity of the spinal cord and surrounding tissue to compensate for alterations in spinal alignment. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Magnetic resonance imaging in the prone position and the diagnosis of tethered spinal cord.

    Science.gov (United States)

    Stamates, Melissa M; Frim, David M; Yang, Carina W; Katzman, Gregory L; Ali, Saad

    2018-01-01

    OBJECTIVE Tethered cord syndrome (TCS) is a neurosurgical disorder with varied clinical manifestations believed to result from vascular compromise due to stretch forces on the spinal cord. Conventional supine MRI findings may include a low-lying conus medullaris, thickened or fat-infiltrated filum terminale, or lipoma; however, imaging sensitivity and specificity for tethered cord can be low. The purpose of this study was to evaluate the utility of prone MRI in the diagnosis of tethered and retethered spinal cord. METHODS Medical records were reviewed in 41 patients who underwent surgical release of tethered cord and in whom preoperative prone MRI sequences were available. Patients were divided into Group 1 (new TCS diagnosis) and Group 2 (recurrent TCS after previous untethering). Absolute conus ventral motion and motion as a percentage of canal width between supine and prone positions was measured in these 2 groups via sagittal T2-weighted sequences; these groups were compared with 30 consecutive patients (Group 3) who were classified as the normal control group. RESULTS The mean ventral motion was as follows: Group 1 (absolute: 0.5 ± 0.5 mm [range 0-2.4 mm]; canal percentage: 3.7% ± 3.9% [range 0%-16.3%]); Group 2 (absolute: 0.4 ± 0.7 mm [range 0-2.6 mm]; canal percentage: 2.2% ± 3.7% [range 0%-14.0%]); and Group 3 (absolute: 3.4 ± 1.3 mm [range 1.4-5.6 mm]; canal percentage: 22.0% ± 7.2% [range 10.5%-36.1%]). Whereas 38/41 surgically treated patients with TCS had diminished ( 10% canal width motion. Sensitivity and specificity were thereby calculated as 92.7% and 100%, respectively. CONCLUSIONS In the present series, prone imaging is found to be a sensitive and specific tool, and the authors believe it may have a role as supportive evidence in the diagnosis of tethered and retethered spinal cord.

  7. Long-term evaluation of intraoperative neurophysiological monitoring-assisted tethered cord surgery

    NARCIS (Netherlands)

    Dulfer, S E; Drost, G; Lange, F; Journee, H L; Wapstra, F H; Hoving, E W

    2017-01-01

    PURPOSE: Patients with tethered spinal cord have been investigated for short-term effects after tethered spinal cord surgery in the past. However, little is known about the long-term effects in this patient group. In this retrospective, longitudinal, observational study, a patient sample of a

  8. Recurrent Abortion and Tethered Cord Syndrome Caused by Anterior Sacral Meningocele: A Report of a Rare Case with a Review of the Literature.

    Science.gov (United States)

    Gupta, Shruti; Chunnilal, Jayesh; Mehrotra, Manasi; Mehrotra, Anant; Srivastava, Arun K; Das, Kuntal K

    2017-05-01

    Anterior sacral meningocele is a rare congenital anomaly. This rare anomaly is described in a young woman who presented with recurrent abortion and later with a huge palpable mass of pelvic origin, measuring 14 × 12 cm. The various radiologic features, associations such as presacral dermoid as a part of incomplete Currarino syndrome, and the management options available are also discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Tensile radial stress in the spinal cord related to arachnoiditis or tethering: a numerical model.

    Science.gov (United States)

    Bertram, C D; Bilston, L E; Stoodley, M A

    2008-07-01

    Spinal arachnoiditis comprises fibrous scarring of the subarachnoid space, following spinal trauma or inflammation, and is often associated with syringomyelia. We hypothesised that cord-to-dura attachments could cause transient tensile cord radial stress, as pressure waves propagate. This was tested in a fluid-structure interaction model, simulating three types of cord tethering, with 'arachnoiditis' confined to a short mid-section of the cord. The annular system was excited abdominally with a short transient, and the resulting Young and Lamb waves and reflections were analysed. Radial mid-section tethering was less significant than axial tethering, which gave rise to tensile radial stress locally when the cord was not fixed cranially. Simulated as inextensible string connections to the dura, arachnoiditis caused both localised tensile radial stress and localised low pressure in the cord as the transient passed. The extent of these effects was sensitive to the relative stiffness of the dura and cord. Tensile radial stress may create a syrinx in previously normal cord tissue, and transiently lowered pressure may draw in interstitial fluid, causing the syrinx to enlarge if fluid exit is inhibited. The suggested mechanism could also explain the juxtaposition of syrinxes to regions of arachnoiditis.

  10. Holocord syringomyelia secondary to tethered spinal cord associated with anterior sacral meningocele and tailgut cyst: case report and review of literature.

    Science.gov (United States)

    Kemp, Joanna; Guzman, Miguel A; Fitzpatrick, Colleen M; Elbabaa, Samer K

    2014-06-01

    Anterior sacral meningoceles are lesions that are uncommonly reported and can be associated with other pathology including presacral masses, tethered spinal cord, and syringomyelia. Tethered spinal cord and syringomyelia can result in neurologic deficits, while large meningoceles and presacral masses can have gastroenterologic, urologic, reproductive, and oncologic consequences. The authors report a case of a 14-year-old girl with an anterior sacral meningocele, tailgut cyst, and tethered cord with holocord syringomyelia who presented with a tethered cord syndrome, manifested by constipation, urinary retention, bilateral lower extremity weakness, and sensory deficits. After extensive radiographic and urodynamic workups were performed, the patient was treated by the neurosurgery and pediatric surgery teams with a posterior sagittal approach for cord detethering, resection of an intradural cystic mass, resection of the anterior sacral meningocele, and resection of the adjacent presacral mass. After surgical treatment, motor weakness and sensory deficits were resolved, though urinary symptoms persisted. The syrinx resolved after detethering alone. Pathology of the intradural cystic mass and the presacral mass inferior to the anterior sacral meningocele were consistent with tailgut cyst. The patient's clinical and surgical management are discussed, and a literature review related to anterior sacral meningoceles and their related pathologies is presented. An interdisciplinary approach is required for the best treatment of this constellation of findings.

  11. Surgical Treatment of Congenital Scoliosis Associated With Tethered Cord by Thoracic Spine-shortening Osteotomy Without Cord Detethering.

    Science.gov (United States)

    Huang, Jing-Hui; Yang, Wei-Zhou; Shen, Chao; Chang, Michael S; Li, Huan; Luo, Zhuo-Jing; Tao, Hui-Ren

    2015-10-15

    Retrospective case series. To investigate the safety and efficacy of spine-shortening osteotomy for congenital scoliosis with tethered cord. Conventional surgery for congenital scoliosis associated with tethered cord risks the complications of detethering. Spine-shortening osteotomy holds the potential to correct scoliosis and decrease spinal cord tension simultaneously without an extra detethering procedure, but no data on this issue is available. 21 patients (14 females and 7 males, average age 15.4 yr) underwent spine-shortening osteotomy without detethering. All of the patients had tethered cord. Patients with main curve more than 90° underwent vertebral column resection (VCR), whereas the others had pedicle subtraction osteotomy (PSO) performed. The average postoperative follow-up period was 45.2 months. The mean operation time was 544.5 min with average blood loss of 2769.1 ml. The deformity correction was 61.3% in the coronal plane and 43.9° in the sagittal plane. 10 patients had neurological deficits preoperatively. At the final follow-up, the deficits in 8 (80%) patients were significantly improved, whereas 2 (20%) remained unchanged. At final follow-up, 71.4% (5/7) patients reported improvement in motor function, 100% (3/3) had improved pain scores, and 75% (3/4) reported better sensory function after the spine-shortening osteotomy. Urinary dysfunction and bowel incontinence present preoperatively in 3 patients all recovered by final follow-up. 5 (23.8%) patients incurred complications including temporary neurological deterioration in 1 patient, urinary tract infection in 2 patients, cerebrospinal fluid leakage in 1 patient, and blood loss more than 5000 ml in 1 patient. Spine-shortening osteotomy is a safe and effective procedure for congenital scoliosis associated with tethered cord. Spine-shortening osteotomy at the thoracic apical vertebrae level not only corrects the spine deformity but also simultaneously releases the tension of the tethered cord

  12. The value of intraoperative neurophysiological monitoring in tethered cord surgery

    NARCIS (Netherlands)

    Hoving, Eelco W.; Haitsma, Esther; Ophuis, Charlotte M. C. Oude; Journee, Henricus L.

    The value of intraoperative neurophysiological monitoring (IONM) with surgical detethering in dysraphic patients has been questioned. A retrospective analysis of our series of 65 patients is presented with special focus on technical set-up and outcome. All patients were diagnosed with a tethered

  13. Twiddler's syndrome in spinal cord stimulation.

    Science.gov (United States)

    Al-Mahfoudh, Rafid; Chan, Yuen; Chong, Hsu Pheen; Farah, Jibril Osman

    2016-01-01

    The aims are to present a case series of Twiddler's syndrome in spinal cord stimulators with analysis of the possible mechanism of this syndrome and discuss how this phenomenon can be prevented. Data were collected retrospectively between 2007 and 2013 for all patients presenting with failure of spinal cord stimulators. The diagnostic criterion for Twiddler's syndrome is radiological evidence of twisting of wires in the presence of failure of spinal cord stimulation. Our unit implants on average 110 spinal cord stimulators a year. Over the 5-year study period, all consecutive cases of spinal cord stimulation failure were studied. Three patients with Twiddler's syndrome were identified. Presentation ranged from 4 to 228 weeks after implantation. Imaging revealed repeated rotations and twisting of the wires of the spinal cord stimulators leading to hardware failure. To the best of our knowledge this is the first reported series of Twiddler's syndrome with implantable pulse generators (IPGs) for spinal cord stimulation. Hardware failure is not uncommon in spinal cord stimulation. Awareness and identification of Twiddler's syndrome may help prevent its occurrence and further revisions. This may be achieved by implanting the IPG in the lumbar region subcutaneously above the belt line. Psychological intervention may have a preventative role for those who are deemed at high risk of Twiddler's syndrome from initial psychological screening.

  14. Dexmedetomidine for an awake fiber-optic intubation of a parturient with Klippel-Feil syndrome, Type I Arnold Chiari malformation and status post released tethered spinal cord presenting for repeat cesarean section

    Directory of Open Access Journals (Sweden)

    Tanmay H. Shah

    2011-08-01

    Full Text Available Patients with Klippel-Feil Syndrome (KFS have congenital fusion of their cervical vertebrae due to a failure in the normal segmentation of the cervical vertebrae during the early weeks of gestation and also have myriad of other associated anomalies. Because of limited neck mobility, airway management in these patients can be a challenge for the anesthesiologist. We describe a unique case in which a dexmedetomidine infusion was used as sedation for an awake fiber-optic intubation in a parturient with Klippel-Feil Syndrome, who presented for elective cesarean delivery. A 36-yearold female, G2P1A0 with KFS (fusion of cervical vertebrae who had prior cesarean section for breech presentation with difficult airway management was scheduled for repeat cesarean delivery. After obtaining an informed consent, patient was taken in the operating room and non-invasive monitors were applied. Dexmedetomidine infusion was started and after adequate sedation, an awake fiberoptic intubation was performed. General anesthetic was administered after intubation and dexmedetomidine infusion was continued on maintenance dose until extubation. Klippel-Feil Syndrome (KFS is a rare congenital disorder for which the true incidence is unknown, which makes it even rare to see a parturient with this disease. Patients with KFS usually have other congenital abnormalities as well, sometimes including the whole thoraco-lumbar spine (Type III precluding the use of neuraxial anesthesia for these patients. Obstetric patients with KFS can present unique challenges in administering anesthesia and analgesia, primarily as it relates to the airway and dexmedetomidine infusion has shown promising result to manage the airway through awake fiberoptic intubation without any adverse effects on mother and fetus.

  15. Response of Scoliosis in Children with Myelomeningocele to Surgical Release of Tethered Spinal Cord.

    Science.gov (United States)

    Altiok, Haluk; Riordan, Anne; Graf, Adam; Krzak, Joe; Hassani, Sahar

    2016-01-01

    Objective: To examine the effect of surgical tethered cord release (TCR) on scoliosis in children with myelomeningocele. Methods: A retrospective review of 65 pediatric patients with myelomeningocele and TCR. The final sample consisted of 20 patients with scoliosis who were managed conservatively after TCR. Results: Average age at TCR was 6.2 years with average follow-up of 3.8 years. Scoliosis of 1 (5%) patient improved, 7 (35%) were stable, and 12 (60%) worsened (≥10°). Fifty percent of patients ultimately required definitive spinal surgery. TCR release delayed definitive spine surgery for an average of 3.2 years. Sixty-four percent of patients with curves less than or equal to 45° had progression of their curves compared to 50% with curves greater than 45°. For patients with curves less than or equal to 45°, curves progressed in 80% of those younger than 10 years as compared to 25% of those older than 10 years. For patients with curves less than or equal to 45°, 43% required definitive spine surgery as opposed to 83% with curves greater than 45°. Level of neurological involvement (ie, lumbar versus thoracic) and age at untethering emerged as factors influencing the effects of TCR for patients with curves less than or equal to 45°. Lumbar curves had more favorable results. Conclusion: Pediatric patients with myelomeningocele and scoliosis should be closely assessed and monitored. A selective approach for youth with lumbosacral level myelomeningocele and progressive curves less than or equal to 45° may result in scoliosis stabilization and avoidance of definitive surgery.

  16. Anorgasmia in anterior spinal cord syndrome.

    Science.gov (United States)

    Berić, A; Light, J K

    1993-05-01

    Three male and two female patients with anorgasmia and dissociated sensory loss due to an anterior spinal cord syndrome are described. Clinical, neurophysiological and quantitative sensory evaluation revealed preservation of the large fibre dorsal column functions from the lumbosacral segments with concomitant severe dysfunction or absence of the small fibre neospinothalamic mediated functions. These findings indicate a role for the spinothalamic system in orgasm.

  17. Anorgasmia in anterior spinal cord syndrome.

    OpenAIRE

    Berić, A; Light, J K

    1993-01-01

    Three male and two female patients with anorgasmia and dissociated sensory loss due to an anterior spinal cord syndrome are described. Clinical, neurophysiological and quantitative sensory evaluation revealed preservation of the large fibre dorsal column functions from the lumbosacral segments with concomitant severe dysfunction or absence of the small fibre neospinothalamic mediated functions. These findings indicate a role for the spinothalamic system in orgasm.

  18. Anorgasmia in anterior spinal cord syndrome.

    Science.gov (United States)

    Berić, A; Light, J K

    1993-01-01

    Three male and two female patients with anorgasmia and dissociated sensory loss due to an anterior spinal cord syndrome are described. Clinical, neurophysiological and quantitative sensory evaluation revealed preservation of the large fibre dorsal column functions from the lumbosacral segments with concomitant severe dysfunction or absence of the small fibre neospinothalamic mediated functions. These findings indicate a role for the spinothalamic system in orgasm. PMID:8505649

  19. Upper cervical myelopathy due to arachnoiditis and spinal cord tethering from adjacent C-2 osteomyelitis. Case report and review of the literature.

    Science.gov (United States)

    Rajpal, Sharad; Chanbusarakum, Krisada; Deshmukh, Praveen R

    2007-01-01

    Myelopathy caused by a spinal cord infection is typically related to an adjacent compressive lesion such as an epidural abscess. The authors report a case of progressive high cervical myelopathy from spinal cord tethering caused by arachnoiditis related to an adjacent C-2 osteomyelitis. This 70-year-old woman initially presented with a methicillin-sensitive Staphylococcus aureus osteomyelitis involving the C-2 odontoid process. She was treated with appropriate antibiotic therapy but, over the course of 4 weeks, she developed progressive quadriparesis. A magnetic resonance image revealed near-complete resolution of the C-2 osteomyelitis, but new ventral tethering of the cord was observed at the level of the odontoid tip. She subsequently underwent open surgical decompression and cord detethering. Postoperatively she experienced improvement in her symptoms and deficits, which continued to improve 1 year after her surgery. To the authors' knowledge, this is the first reported case of progressive upper cervical myelopathy due to arachnoiditis and cord tethering from an adjacent methicillin-sensitive S. aureus C-2 osteomyelitis.

  20. More preoperative flexibility implies adequate neural pliability for curve correction without prophylactic untethering in scoliosis patients with asymptomatic tethered spinal cord, a retrospective study.

    Science.gov (United States)

    Zhou, Zhenhai; Zhang, Hongqi; Guo, Chaofeng; Yu, Honggui; Wang, Longjie; Guo, Qiang

    2017-06-15

    Tethered spinal cord is frequently associated with scoliosis. It is still controversial whether a prophylactic untethering is necessary before correction procedure in scoliosis patients with tethered spinal cord. In this study we determined the clinical outcome of a one-stage posterior scoliosis correction without a prophylactic untethering for treating scoliosis with an asymptomatic tethered spinal cord. Seventeen (5 males and 12 females) scoliosis patients with tethered spinal cords were retrospectively reviewed. All patients underwent a one-stage posterior scoliosis correction without preventive untethering. Parameters of radiograph were used to assess correction result. The Scoliosis Research Society (SRS)-22 questionnaire was analyzed pre- and post-operatively to evaluate the clinical outcomes. The modified Japanese Orthopaedic Association (mJOA) score was used to assess the pre- and post-operative spinal cord function. The post-operative coronal Cobb angle was significantly decreased compared with preoperative. (23.8 ± 6.4° vs. 58.4 ± 12.6°, P < 0.01). The coronal Cobb angle was 22.4 ± 6.8° at the final follow-up evaluation. The apical vertebral translation (AVT) was also decreased significantly. (27.5 mm vs. 60.9 mm, P < 0.01). The SRS-22 total score was improved at the 1-year follow-up evaluation compared with the pre-operative SRS-22 total score (87 ± 4 vs. 70 ± 5, p < 0.05). The functional activities, pain, self-image, mental health, and surgery satisfactory scores at the final follow-up evaluation were all improved compared with the corresponding pre-operative scores, especially the self-image and mental health scores (p < 0.05). The spinal cord function was stable and there was no new neurological symptoms after scoliosis correction. No difference existed between the pre- and post-operative total mJOA score (26 ± 2 vs. 27 ± 2, p = 0.39), which including subjective symptom (p = 0.07), clinical symptom (p = 0

  1. Metastatic spinal cord syndromes: imaging appearances and treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Abdi, S. [Department of Radiology, Nottingham City Hospital, Nottingham (United Kingdom)]. E-mail: shahramabdi@hotmail.com; Adams, C.I. [Centre for Spinal Studies and Surgery, Queen' s Medical Centre, University Hospital, Nottingham (United Kingdom); Foweraker, K.L. [Department of Oncology, Nottingham City Hospital, Nottingham (United Kingdom); O' Connor, A. [Department of Radiology, Nottingham City Hospital, Nottingham (United Kingdom)

    2005-06-01

    Metastatic spinal cord syndromes usually result from neural compression by adjacent vertebral disease but are occasionally caused by intradural or intramedullary disease. MRI is the most accurate method for evaluation of such syndromes. Knowledge of the relevant imaging appearances and therapeutic options enables the radiologist to make an accurate assessment of the extent of disease and contribute information relevant to treatment planning.

  2. Multiple neural tube defects: a rare combination of limited dorsal myeloschisis, diplomyelia with dorsal bony spur, sacral meningocoele, syringohydromyelia, and tethered cord.

    Science.gov (United States)

    Shashank R, Ramdurg; Shubhi, Dubey; Vishal, Kadeli

    2017-04-01

    Multiple neural tube defects are relatively rare. They account for less than 1% reported neural tube defects. Cases of limited dorsal myeloschisis (LDM) and diplomyelia (two cords in single sac without intervening bony or fibrous septae) with dorsal bony spur are also a rare event. Here, the authors report a rare case of neonate with thoracic LDM, diplomyelia with dorsal bony spur, sacral meningocoele with syringohydromyelia, and low-lying tethered cord. The child also had a ventricular septal defect (VSD) and bilateral rocker bottom feet. Various environmental factors and genetic mutations in transmembrane proteins have been studied in animal models explaining the origin of neural tube defects. To the best of author's knowledge, this is the first case of varied multiple neural tube defects with diplomyelia reported in world literature.

  3. Vocal cord paralysis associated with Ramsay Hunt syndrome

    DEFF Research Database (Denmark)

    Rasmussen, Eva Rye; Mey, Kristianna

    2014-01-01

    and dysphagia. We present a case of Ramsay Hunt syndrome combined with unilateral hearing loss and left vocal cord paralysis. The patient underwent MRI, CT and a lumbar puncture causing anxiety in the patient and delaying the initiation of antiviral and anti-inflammatory treatment, which is only efficient when...

  4. Spinal cord stimulation in chronic pain syndromes

    NARCIS (Netherlands)

    ten Vaarwerk, IAM; Staal, MJ

    1998-01-01

    Spinal cord stimulation (SCS) has been used for more than 30 years now, and although it has shown to be effective under certain well-described conditions of chronic pain, conclusive evidence on its effectiveness is still sparse. There is a need for more prospective and methodological good studies,

  5. Paraplegia como manifestação inicial de medula presa: relato de caso Paraplegia as initial manifestation of tethered spinal cord: case report

    Directory of Open Access Journals (Sweden)

    ANA GUARDIOLA

    1999-03-01

    Full Text Available A medula presa (MP é entidade pouco frequente que ocorre quando há restrição da migração normal do cone medular por cistos, lipomas ou disrafismos espinhais. Esta patologia pode levar a paraplegia, distúrbios sensoriais e esficterianos. Relatamos o caso de uma menina de 22 meses que consultou com quadro de paraplegia. O diagnóstico de medula presa foi confirmado pela mielotomografia e a paciente foi submetida à cirurgia para liberação do filo terminal.Tethered spinal cord (TSC is a rare disorder; it occurs when the conus medularis is anchored to the base of the vertebral canal by thickened filum terminale cysts, lipoma and spinal dysraphia. This disorder may cause paraplegia, sensory and sphincter disturbance. We report a twenty-two months-old girl presenting with paraplegia. TSC diagnostic was confirmed by myelotomography. The patient was submitted to surgical relief of tethered filum terminale.

  6. Spinal cord ischemia: aetiology, clinical syndromes and imaging features

    Energy Technology Data Exchange (ETDEWEB)

    Weidauer, Stefan [Frankfurt Univ., Sankt Katharinen Hospital Teaching Hospital, Frankfurt am Main (Germany). Dept. of Neurology; Hattingen, Elke; Berkefeld, Joachim [Frankfurt Univ., Frankfurt am Main (Germany). Inst. of Neuroradiology; Nichtweiss, Michael

    2015-03-01

    The purpose of this study was to analyse MR imaging features and lesion patterns as defined by compromised vascular territories, correlating them to different clinical syndromes and aetiological aspects. In a 19.8-year period, clinical records and magnetic resonance imaging (MRI) features of 55 consecutive patients suffering from spinal cord ischemia were evaluated. Aetiologies of infarcts were arteriosclerosis of the aorta and vertebral arteries (23.6 %), aortic surgery or interventional aneurysm repair (11 %) and aortic and vertebral artery dissection (11 %), and in 23.6 %, aetiology remained unclear. Infarcts occurred in 38.2 % at the cervical and thoracic level, respectively, and 49 % of patients suffered from centromedullar syndrome caused by anterior spinal artery ischemia. MRI disclosed hyperintense pencil-like lesion pattern on T2WI in 98.2 %, cord swelling in 40 %, enhancement on post-contrast T1WI in 42.9 % and always hyperintense signal on diffusion-weighted imaging (DWI) when acquired. The most common clinical feature in spinal cord ischemia is a centromedullar syndrome, and in contrast to anterior spinal artery ischemia, infarcts in the posterior spinal artery territory are rare. The exclusively cervical location of the spinal sulcal artery syndrome seems to be a likely consequence of anterior spinal artery duplication which is observed preferentially here. (orig.)

  7. Intrapleural migration of a spinal catheter in a patient with arachnoiditis and extensive epidural scarring after tethered cord release: a case report and review of literature.

    Science.gov (United States)

    Anitescu, Magdalena; DaSilva, Arnaldo Neves; Frim, David M

    2012-01-01

    The objective of this study was to report a case of new onset refractory pain from intrapleural migration of a spinal catheter five months after the implantation of an intrathecal drug delivery system (IDDS). A 57-year-old man had intractable pain because of multiple intradural spinal explorations for tethered cord release. His pain was effectively treated with intrathecal morphine via an IDDS. Five months after the implantation, the patient developed return of the original pain more than two weeks after intrapleural migration of the intrathecal catheter. The migration was documented by computed tomography, and repositioning of the catheter rendered the patient comfortable. The gradual onset of pain may have been due to decreasing delivery of drug to the cerebrospinal fluid as the catheter tip migrated further away from the dura. To our knowledge, this complication has not been reported in the literature. Physicians and nursing staff that place and manage an IDDS should be aware of this complication. © 2012 International Neuromodulation Society.

  8. Posterior reversible encephalopathy syndrome with spinal cord involvement (PRES-SCI: A case report

    Directory of Open Access Journals (Sweden)

    Harsh Vardhan Khokhar

    2016-01-01

    Full Text Available Posterior reversible encephalopathy syndrome with spinal cord involvement (PRES-SCI is a recently described entity with a handful of cases reported in literature. We describe a case of PRES in setting of Henoch-Schönlein purpura (HSP with involvement of brain stem and spinal cord.

  9. Intramedullary spinal cord metastasis from colonic carcinoma presenting as Brown-Sequard syndrome: a case report

    LENUS (Irish Health Repository)

    Kaballo, Mohammed A

    2011-08-02

    Abstract Introduction Intramedullary spinal cord metastasis is very rare. The majority are discovered incidentally during autopsy. Most symptomatic patients present with rapidly progressive neurological deficits and require immediate examination. Few patients demonstrate features of Brown-Séquard syndrome. Radiotherapy is the gold-standard of therapy for Intramedullary spinal cord metastasis. The overall prognosis is poor and the mortality rate is very high. We present what is, to the best of our knowledge, the first case of Intramedullary spinal cord metastasis of colorectal carcinoma presenting as Brown-Séquard syndrome. Case presentation We present the case of a 71-year-old Caucasian man with colonic adenocarcinoma who developed Intramedullary spinal cord metastasis and showed features of Brown-Séquard syndrome, which is an uncommon presentation of Intramedullary spinal cord metastasis. Conclusion This patient had an Intramedullary spinal cord metastasis, a rare form of metastatic disease, secondary to colonic carcinoma. The metastasis manifested clinically as Brown-Séquard syndrome, itself a very uncommon condition. This syndrome is rarely caused by intramedullary tumors. This unique case has particular interest in medicine, especially for the specialties of medical, surgical and radiation oncology. We hope that it will add more information to the literature about these entities.

  10. Evidence-based management of central cord syndrome.

    Science.gov (United States)

    Dahdaleh, Nader S; Lawton, Cort D; El Ahmadieh, Tarek Y; Nixon, Alexander T; El Tecle, Najib E; Oh, Sanders; Fessler, Richard G; Smith, Zachary A

    2013-07-01

    Evidence-based medicine is used to examine the current treatment options, timing of surgical intervention, and prognostic factors in the management of patients with traumatic central cord syndrome (TCCS). A computerized literature search of the National Library of Medicine database, Cochrane database, and Google Scholar was performed for published material between January 1966 and February 2013 using key words and Medical Subject Headings. Abstracts were reviewed and selected, with the articles segregated into 3 main categories: surgical versus conservative management, timing of surgery, and prognostic factors. Evidentiary tables were then assembled, summarizing data and quality of evidence (Classes I-III) for papers included in this review. The authors compiled 3 evidentiary tables summarizing 16 studies, all of which were retrospective in design. Regarding surgical intervention versus conservative management, there was Class III evidence to support the superiority of surgery for patients presenting with TCCS. In regards to timing of surgery, most Class III evidence demonstrated no difference in early versus late surgical management. Most Class III studies agreed that older age, especially age greater than 60-70 years, correlated with worse outcomes. No Class I or Class II evidence was available to determine the efficacy of surgery, timing of surgical intervention, or prognostic factors in patients managed for TCCS. Hence, there is a need to perform well-controlled prospective studies and randomized controlled clinical trials to further investigate the optimal management (surgical vs conservative) and timing of surgical intervention in patients suffering from TCCS.

  11. A case of Moebius syndrome presenting with congenital bilateral vocal cord paralysis.

    Science.gov (United States)

    Kanemoto, Nobuko; Kanemoto, Katsuyoshi; Kamoda, Tomohiro; Hasegawa, Makoto; Arinami, Tadao

    2007-08-01

    We describe a female infant with bilateral facial paralysis and abducens palsy. To the best of our knowledge, this is the first report of Moebius syndrome presenting with congenital bilateral vocal cord paralysis (CBVCP). Although CBVCP can be part of a recognizable syndrome, i.e. Down syndrome, 22q deletion syndrome, Robinow's syndrome and cerebro-oculo-facio-skeletal syndrome, no reports of Moebius syndrome with CBVCP were found in the literature. CBVCP is often associated with central nervous system abnormalities. However, our patient had no detectable brain abnormalities. The etiology of Moebius syndrome remains unknown. It is interesting that the clinical manifestations of Moebius syndrome can include CBVCP. However, the pathophysiology of CBVCP is unknown and further investigations into the etiology of Moebius syndrome are required.

  12. MRI of anterior spinal artery syndrome of the cervical spinal cord

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, S. (Dept. of Radiology, Tohoku Univ. School of Medicine, Sendai (Japan)); Yamada, T. (Dept. of Radiology, Tohoku Univ. School of Medicine, Sendai (Japan)); Ishii, K. (Dept. of Radiology, Tohoku Univ. School of Medicine, Sendai (Japan)); Saito, H. (Dept. of Neurology, Tohoku Univ. School of Medicine, Sendai (Japan)); Tanji, H. (Dept. of Neurology, Tohoku Univ. School of Medicine, Sendai (Japan)); Kobayashi, T. (Inst. of Rehabilitation Medicine, Tohoku Univ. School of Medicine, Miyagi (Japan)); Soma, Y. (Div. of Neurology, Takeda Hospital, Aizuwakamatsu (Japan)); Sakamoto, K. (Dept. of Radiology, Tohoku Univ. School of Medicine, Sendai (Japan))

    1992-12-01

    Cervical spinal cord lesions in the anterior spinal artery syndrome were delineated on magnetic resonance images (MRI) in four patients. The lesion was always seen anteriorly in the cervical cord. On T2-weighted images, the lesions appeared hyperintense relative to the normal spinal cord, while on T1-weighted images, two chronic lesions appeared hypointense, with local atrophy of the cord. In one case, repeated T1-weighted images showed no signal abnormality 4 days after the ictus, but the lesion became hypointense 18 days later, when contrast enhancement was also recognized after injection of Gd-DTPA; this sequence of intensity changes was similar to that of cerebral infarction. The extent of the lesion seen MRI correlated closely with neurological findings in all cases. Although the findings may not be specific, MRI is now the modality of choice for confirming the diagnosis in patients suspected of having an anterior spinal artery syndrome. (orig.)

  13. Acute traumatic central cord syndrome: analysis of clinical and radiological correlations.

    Science.gov (United States)

    Miranda, P; Gomez, P; Alday, R

    2008-12-01

    In patients with traumatic spinal cord injury, several studies correlate neurological impairment and radiological findings. However, little information is available about this correspondence in the particular group of acute traumatic central cord syndrome. The object of the present work was to describe the clinical and radiological features of a series of patients presenting with acute traumatic central cord syndrome and to analyze clinical and radiological correlations on admission and at last follow-up. Retrospective review of 15 patients diagnosed of acute traumatic central cord syndrome between 1995 and 2005. Global motor score and motor score in upper extremities were determined on admission and at last follow-up (6 months-4 years, mean 16 months). Plain films, cervical computed tomography and magnetic resonance (MR) were performed in every patient and retrieved for the study. In seven patients, serial MR studies were performed during follow-up. Clinical and radiological correlations were statistically analyzed with non-parametric tests. Cervical spondylosis appeared associated with older age, falls, and absence of fracture. Spinal cord edema was the most common finding in MR studies but hemorrhage was also observed. The length of spinal cord edema significantly correlated with initial motor score. The decrease in T2-weighted hyperintensity in serial MR studies correlated with the gain of motor power in upper limbs at last follow-up. Elderly patients with more degenerated cervical spines commonly develop acute traumatic central cord syndrome after incidental falls. Length of spinal cord edema correlates with neurological impairment on admission and may provide significant prognostic information.

  14. Transitory spinal cord swelling in a 6-year-old boy with Guillain-Barre syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Delhaas, T. [Section of Child Neurology, Wilhelmina Children`s Hospital, University Hospital for Children and Youth, Utrecht (Netherlands)]|[Department of Pediatrics, University Hospital Maastricht, P0 Box 5800, 6202 AZ Maastricht (Netherlands); Kamphuis, D.J. [Section of Child Neurology, Wilhelmina Children`s Hospital, University Hospital for Children and Youth, Utrecht (Netherlands); Witkamp, T.D. [Department of Radiology, University Hospital Utrecht, Utrecht (Netherlands)

    1998-07-01

    A 6-year-old boy developed progressive motor weakness and areflexia. The clinical picture, combined with electrophysiological findings, indicated a diagnosis of Guillain-Barre syndrome (GBS). MRI on admission revealed spinal cord swelling and increased signal intensity within the cord. It is concluded that, since a degree of central nervous system involvement can occasionally be part of the spectrum of GBS, swelling of the spinal cord without contrast enhancement does not exclude a diagnosis of GBS. (orig.) With 2 figs., 8 refs.

  15. Reversible Hypertensive Myelopathy-The Spinal Cord Variant of Posterior Reversible Encephalopathy Syndrome.

    Science.gov (United States)

    Gocmen, Rahsan; Ardicli, Didem; Erarslan, Yasin; Duzova, Ali; Anlar, Banu

    2017-04-01

    The posterior reversible encephalopathy syndrome (PRES) is a well-known clinical and radiologic entity mainly affecting the territory of the posterior cerebral circulation. Spinal cord involvement is extremely rare, and as of yet, only a few cases have been reported in the literature. The present case describes a reversible, longitudinal spinal cord lesion in a patient with high blood pressure. We discuss the differential diagnosis of longitudinal myelopathy and focus on the clinical presentation, diagnosis, and management of the "spinal cord variant of PRES." Georg Thieme Verlag KG Stuttgart · New York.

  16. Floating-Harbor syndrome and intramedullary spinal cord ganglioglioma: case report and observations from the literature.

    Science.gov (United States)

    Nelson, Rachel A; McNamara, Michelle; Ellis, William; Stein-Wexler, Rebecca; Moghaddam, Billur; Zwerdling, Theodore

    2009-10-01

    We report on a 5-year-old male with expressive language delay, developmental delay, short stature, and facial anomalies consistent with Floating-Harbor syndrome (FHS). In addition, he developed an intramedullary ganglioglioma. This is the first reported case of a tumor associated with FHS, and may represent an as yet undefined genetic link between spinal cord tumors and FHS, adding this syndrome to the growing list of disorders with a predisposition for tumor development.

  17. Tethered Lubricants

    Energy Technology Data Exchange (ETDEWEB)

    Archer, Lynden

    2010-09-15

    We have performed extensive experimental and theoretical studies of interfacial friction, relaxation dynamics, and thermodynamics of polymer chains tethered to points, planes, and particles. A key result from our tribology studies using lateral force microscopy (LFM) measurements of polydisperse brushes of linear and branched chains densely grafted to planar substrates is that there are exceedingly low friction coefficients for these systems. Specific project achievements include: (1) Synthesis of three-tiered lubricant films containing controlled amounts of free and pendent PDMS chains, and investigated the effect of their molecular weight and volume fraction on interfacial friction. (2.) Detailed studies of a family of hairy particles termed nanoscale organic hybrid materials (NOHMs) and demonstration of their use as lubricants.

  18. Diagnostic criteria of traumatic central cord syndrome. Part 2: a questionnaire survey among spine specialists.

    NARCIS (Netherlands)

    Middendorp, J.J. van; Pouw, M.H.; Hayes, K.C.; Williams, R.; Chhabra, H.S.; Putz, C.; Veth, R.P.H.; Geurts, A.C.H.; Aito, S.; Kriz, J.; McKinley, W.; Asbeck, F.W. van; Curt, A.; Fehlings, M.G.; Meent, H. van de; Hosman, A.J.F.

    2010-01-01

    STUDY DESIGN: A questionnaire survey. OBJECTIVES: To evaluate the need for the introduction of quantitative diagnostic criteria for the traumatic central cord syndrome (TCCS). SETTING: An online questionnaire survey with participants from all over the world. METHODS: An invitation to participate in

  19. Postpartum spinal cord injury in a woman with HELLP syndrome.

    NARCIS (Netherlands)

    Groothuis, J.T.; Kuppevelt, DH van

    2008-01-01

    OBJECTIVE: To report a rare cause of spinal cord injury. STUDY DESIGN: Case report. CASE REPORT: A 36-year-old woman presented with acute onset of paresis of the upper and lower extremity (level C5, ASIA B) the day after delivering a healthy daughter (39 weeks' gestation). Prior to giving birth, she

  20. Relative shortening and functional tethering of spinal cord in adolescent scoliosis – Result of asynchronous neuro-osseous growth, summary of an electronic focus group debate of the IBSE

    Directory of Open Access Journals (Sweden)

    Burwell R Geoffrey

    2008-06-01

    Full Text Available Abstract There is no generally accepted scientific theory for the causes of adolescent idiopathic scoliosis (AIS. As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE introduced the electronic focus group (EFG as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The Statement for this debate was written by Dr WCW Chu and colleagues who examine the spinal cord to vertebral growth interaction during adolescence in scoliosis. Using the multi-planar reconstruction technique of magnetic resonance imaging they investigated the relative length of spinal cord to vertebral column including ratios in 28 girls with AIS (mainly thoracic or double major curves and 14 age-matched normal girls. Also evaluated were cerebellar tonsillar position, somatosensory evoked potentials (SSEPs, and clinical neurological examination. In severe AIS compared with normal controls, the vertebral column is significantly longer without detectable spinal cord lengthening. They speculate that anterior spinal column overgrowth relative to a normal length spinal cord exerts a stretching tethering force between the two ends, cranially and caudally leading to the initiation and progression of thoracic AIS. They support and develop the Roth-Porter concept of uncoupled neuro-osseous growth in the pathogenesis of AIS which now they prefer to term 'asynchronous neuro-osseous growth'. Morphological evidence about the curve apex suggests that the spinal cord is also affected, and a 'double pathology' is suggested. AIS is viewed as a disorder with a wide spectrum and a common neuroanatomical abnormality namely, a spinal cord of normal length but short relative to an abnormally lengthened anterior vertebral column. Neuroanatomical changes and/or abnormal neural function may be expressed only in severe cases. This asynchronous neuro-osseous growth

  1. Sertoli cell tumors associated with feminizing syndrome and spermatic cord torsion in two cryptorchid dogs

    Science.gov (United States)

    Quartuccio, Marco; Garufi, Giuseppe; Cristarella, Santo; Zanghì, Antonina

    2012-01-01

    The association of cryptorchidism, functional Sertoli cell tumors, and spermatic cord torsion has been rarely reported in the literature. Two dogs were admitted for bilateral skin alopecia and weight loss. Both animals were cryptorchid and displayed a pendulous preputial sheath, prostate hypertrophy, and increased levels of circulating oestrogen. Transabdominal palpation and ultrasonography revealed the presence of neoplastic retained gonads. During surgery, spermatic cord torsion was also detected in the enlarged neoplastic testes of both dogs. Histologic examination confirmed the presence of Sertoli cell tumors that were primarily responsible for the feminizing syndrome. Complete remission of all symptoms occurred within 3 months after orchiectomy. PMID:22705745

  2. Toxoplasmosis of spinal cord in acquired immunodeficiency syndrome patient presenting as paraparesis: A rare entity

    Directory of Open Access Journals (Sweden)

    Sachin R Agrawal

    2014-01-01

    Full Text Available Although brain has been the most common site for toxoplasma infection in acquired immunodeficiency syndrome patients, involvement of spinal cord by toxoplasma has been rarely found. Spinal cord toxoplasmosis can present as acute onset weakness in both lower limbs associated with sensory and bladder dysfunction. A presumptive diagnosis can be made in patients with CD4 count <100/mm 3 based on a positive serum Toxoplasma gondii IgG antibodies, no recent prophylaxis against toxoplasmosis, intramedullary ring enhancing lesion in spinal cord supported by similar lesions in brain parenchyma. Institutions of antitoxoplasma treatment in such patients result in prompt clinical response and therefore avoiding the need of unnecessary invasive diagnostic tests. Here, we report a case of toxoplasmic myelitis in immunocompromised patient presenting as myelopathy who showed significant clinical improvement after starting antitoxoplasma treatment. Hence toxoplasmic myelitis should be considered in toxoplasma seropositive immunocompromised patients presenting as myelopathy and imaging studies showing ring enhancing intramedullary lesion.

  3. Evaluation of pain syndromes in war veterans with spinal cord injury

    Directory of Open Access Journals (Sweden)

    Ahmad Zeinali

    2016-07-01

    Full Text Available Chronic pain is one of the most important problems in patients with spinal cord injury. The pain may occur for unknown reasons, but in most cases it is due to damage to the nerves due to spinal cord injury or musculoskeletal problems. The aim of this study was to investigate the epidemiology of pain syndromes in veterans of war and relationship between age, gender and severity of spinal cord injury with treatment response in such people. This was is a descriptive study on spinal cord injury victims in Yazd and Isfahan from May to November 2015. First, a questionnaire was prepared in which information such as age, duration of disease, pain, level of injury and the type of drug were included. The patients were examined individually to determine the level of damage properly. Finally, by statistical analysis of data obtained, their relationship was examined. In this study, 50 people with injured spinal cord in the provinces of Yazd and Isfahan (18 out of Yazd Province and 32 from the province were evaluated, of which 13 complexities were in the cervical level (neck, 27 in the thoracic region and 10 in the lumbar region. The lowest age was 39 years and oldest age was 50 years. Statistical analysis of the relationship between pain and level of spinal cord injury showed that no significant relationship between severity of pain and level of spinal cord injury. Statistical analysis of the relationship between severity of pain and age suggested that older patients had complained of less pain than patients with lower ages. It seems that due to the problems facing patients with spinal defects, especially disabled veterans, comprehensive program must be carried out by relevant institutions to facilitate the treatment of these people and increase the quality of their life.

  4. Bilateral complex regional pain syndrome following spinal cord injury and bilateral calcaneus fracture

    Directory of Open Access Journals (Sweden)

    Ahmet Boyacı

    2013-09-01

    Full Text Available Complex regional pain syndrome (CRPS is a disease affectingone or more extremities, characterized by spontaneouspain, allodynia, hyperpathia and hyperalgesia.CRPS is separated into Type 1 and Type 2. CRPS whichdevelops after a nociceptive event is labeled as Type 1and when it develops following peripheral nerve damage,Type 2. Although the pathogenesis is not fully understood,peripheral and central sensitivity are held responsible.Bilateral lower extremity involvement is extremely rare.However, it should be borne in mind that it can develop intraumatic injuries which occur in more than one area anddiagnosis and commencement of a rehabilitation programshould be made in the early period. The case is presentedhere of bilateral Type 1 CRPS developing after incompletespinal cord injury and bilateral calcaneus fracture. JClin Exp Invest 2013; 4 (3: 360-363Key words: complex regional pain syndrome, calcaneusfracture, spinal cord injury

  5. SPINAL CORD STIMULATION IN TREATMENT OF THE NEUROPATHIC PAIN SYNDROMES: INITIAL EXPERIENCE

    Directory of Open Access Journals (Sweden)

    D. A. Rzaev

    2010-01-01

    Full Text Available In the article initial experience of spinal cord stimulation for chronic pain syndromes is described. The trial was done for 62 patients, in 52 cases trial was successful and subcutaneous pulse generator were implanated. Maximal follow-up is 26 months. The level of pain evaluates at VAS. Permanent pain-relieve results were achieved in 46 patients (74,2%. These results correspond to literature data.

  6. Factor analysis of the metabolic syndrome in spinal cord-injured men.

    Science.gov (United States)

    Jones, Lynnette M; Legge, Michael; Goulding, Ailsa

    2004-10-01

    Disturbances of carbohydrate and lipid metabolism in men with spinal cord injury are common, but poorly defined. Clustering of recognized risk factors for obesity and disorders of carbohydrate and lipid metabolism are characteristic of the metabolic syndrome. The purpose of this study was to investigate the presence of metabolic syndrome using modifications of the World Health Organization (WHO) definition and including total physical activity levels (minutes/week), in a group of active males with spinal cord injury who were carefully matched for age, height, and weight with active able-bodied males. Factor analysis is used widely to explore factors of the metabolic syndrome. This technique was used in this study of 20 spinal cord-injured (SCI) men and 20 able-bodied controls, matched for age, height, and weight. Three-factor models, each reflecting a different aspect of the metabolic syndrome, were identified for both study groups. The average communality score for the SCI group was 0.8 and 0.7 for the control group. For the SCI group, factor 1 reflected an interaction between adiposity measures, physical activity, and postload insulin and glucose, factor 2 was reflective of dyslipidemia, while factor 3 revealed an interaction between fasting levels of insulin and glucose. In the control group, factor 1 reflected an association between the adiposity measures and physical activity, factor 2 was reflective of postload glycemic control, with factor 3 reflecting an interaction between fasting insulin and dyslipidemia. By summation of the total variance of each factor, the 3-factor models explained 80% and 69% of the variance in the original 9 variables examined in the SCI and control groups, respectively. In summary, while the WHO definition for the metabolic syndrome appears suitable for use in identifying the incidence of this syndrome in SCI men, some modification of anthropometric and lipid measures may be required.

  7. Tethering a new technology

    Science.gov (United States)

    Stone, Nobie H.; Candidi, Maurizio

    1993-01-01

    In a tethered-satellite system, two satellites travelling in different orbits are forced to circle the earth in the same time period. The lower satellite is dragged by the tether to a higher orbital speed, while the upper one tends to move higher. This generates a tension which maintains the system in a stable configuration; the tether is aligned with a radius projecting outward from the earth's center. Such a system has been demonstrated by the TSS-1 tethered satellite carried by the Space Shuttle's STS-46 mission. The dynamic and the electrodynamic behavior of the system at long tether lengths were not, however, evaluated due to system malfunctions.

  8. Electroencephalographic evoked pain response is suppressed by spinal cord stimulation in complex regional pain syndrome: a case report.

    Science.gov (United States)

    Hylands-White, Nicholas; Duarte, Rui V; Beeson, Paul; Mayhew, Stephen D; Raphael, Jon H

    2016-12-01

    Pain is a subjective response that limits assessment. The purpose of this case report was to explore how the objectivity of the electroencephalographic response to thermal stimuli would be affected by concurrent spinal cord stimulation. A patient had been implanted with a spinal cord stimulator for the management of complex regional pain syndrome of both hands for 8 years. Following ethical approval and written informed consent we induced thermal stimuli using the Medoc PATHWAY Pain & Sensory Evaluation System on the right hand of the patient with the spinal cord stimulator switched off and with the spinal cord stimulator switched on. The patient reported a clinically significant reduction in thermal induced pain using the numerical rating scale (71.4 % reduction) with spinal cord stimulator switched on. Analysis of electroencephalogram recordings indicated the occurrence of contact heat evoked potentials (N2-P2) with spinal cord stimulator off, but not with spinal cord stimulator on. This case report suggests that thermal pain can be reduced in complex regional pain syndrome patients with the use of spinal cord stimulation and offers objective validation of the reported outcomes with this treatment.

  9. Two cases of Brown-Séquard syndrome in penetrating spinal cord injuries.

    Science.gov (United States)

    Amendola, L; Corghi, A; Cappuccio, M; De Iure, F

    2014-01-01

    Brown-Séquard syndrome due to a stab injuries is uncommon and results from a lesion in one half of the spinal cord. The role of surgery in the treatment of penetrating spinal injury often remain controversial. To discuss the current diagnostic and therapeutic approach for these types of injuries. The Authors describe two rare cases of Brown-Séquard syndrome due to civilian stab injuries differently treated. Mechanism of damage, clinical features and neurological outcome are reported. The recovery of neurological function in the first case indicates that the spinal tracts were injured by a contusion, rather than by a direct injury as in the second case. Moreover, surgery was required in the second patient to remove the weapon and to stabilize the spine, presenting bony and ligamentous instability. The diagnostic and therapeutic management are debated. An overview on clinical research in sperimental medical treatment of spinal cord injury was considered to evaluate future possible approaches to these injuries. As the neurologic improvement depends on the type and severity of the spinal cord damage, the indications for acute surgical management are limited and conservative management should be preferred.

  10. Testicular cancer in Down syndrome with spinal cord metastases

    Directory of Open Access Journals (Sweden)

    Turky Almouhissen

    2016-01-01

    Full Text Available A 22-year-old male patient with Down syndrome was referred to our hospital with a vast left testicular mass. He underwent a left radical inguinal orchiectomy, and a histopathological examination of the mass showed a yolk sac tumor invading the epididymis. The patient was discharged in a satisfactory condition. Sixteen days later, the patient presented again complaining of lower limb weakness. Magnetic resonance imaging of the spine showed metastatic lesions compressing the dorsal spine, and he underwent emergency surgical decompression. The histopathology of the metastatic lesions revealed a yolk sac subtype which was identical to his primary testicular tumor.

  11. Testicular cancer in Down syndrome with spinal cord metastases

    Science.gov (United States)

    Almouhissen, Turky; Badr, Hattan; AlMatrafi, Bassam; Alessa, Noor; Nassir, Anmar

    2016-01-01

    A 22-year-old male patient with Down syndrome was referred to our hospital with a vast left testicular mass. He underwent a left radical inguinal orchiectomy, and a histopathological examination of the mass showed a yolk sac tumor invading the epididymis. The patient was discharged in a satisfactory condition. Sixteen days later, the patient presented again complaining of lower limb weakness. Magnetic resonance imaging of the spine showed metastatic lesions compressing the dorsal spine, and he underwent emergency surgical decompression. The histopathology of the metastatic lesions revealed a yolk sac subtype which was identical to his primary testicular tumor. PMID:28058004

  12. Spinal cord stimulation to abort painful spasms of atypical stiff limb syndrome.

    Science.gov (United States)

    Ughratdar, I; Sivakumar, G; Basu, S

    2010-01-01

    Stiff limb syndrome (SLS) is a rare chronic condition which can result in significant debility. We report the case of a 44-year-old man suffering from severe painful spasms in his right leg with a diagnosis of SLS. He had been initially treated for his pain with a spinal cord stimulator but presented with exacerbation of pain secondary to a lead fracture for which he underwent revision of the stimulator. Postoperative programming unexpectedly resulted in not only control of his pain but also an ability to abort his spasmodic episodes related to SLS. To our knowledge, spinal cord stimulation has not been previously used for SLS and our report opens up another avenue for this rare condition. We provide a brief overview of SLS and propose an underlying mechanism for the observed phenomenon.

  13. Spinal cord toxoplasmosis in human immunodeficiency virus infection/acquired immunodeficiency syndrome.

    Science.gov (United States)

    García-García, Concepción; Castillo-Álvarez, Federico; Azcona-Gutiérrez, José M; Herraiz, María J; Ibarra, Valvanera; Oteo, José A

    2015-05-01

    Neurological complications in patients with human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS) are still common, even in the era of highly active antiretroviral therapy. Opportunistic infections, immune reconstitution, the virus itself, antiretroviral drugs and neurocognitive disorders have to be considered when establishing the differential diagnosis. Toxoplasmic encephalitis remains the major cause of space-occupying lesions in the brain of patients with HIV/AIDS; however, spinal cord involvement has been reported infrequently. Here, we review spinal cord toxoplasmosis in HIV infection and illustrate the condition with a recent case from our hospital. We suggest that most patients with HIV/AIDS and myelitis with enhanced spine lesions, multiple brain lesions and positive serology for Toxoplasma gondii should receive immediate empirical treatment for toxoplasmosis, and a biopsy should be performed in those cases without clinical improvement or with deterioration.

  14. Pathology of roots, spinal cord and brainstem in syringomyelia-like syndrome of Tangier disease.

    Science.gov (United States)

    Antoine, J C; Tommasi, M; Boucheron, S; Convers, P; Laurent, B; Michel, D

    1991-12-01

    We report here a post-mortem examination of a 46-year-old patient who died after a 23-year-long syringomyelia-like syndrome of Tangier disease. The L5 dorsal root and the superficial peroneal nerve showed fiber loss and lipid vacuole accumulation in Schwann cell cytoplasm. The L5 ventral root had moderate fiber loss without lipid vacuoles. In the cervical roots, fiber loss was intense and there were no foamy Schwann cells. Motor neuron loss was severe in the cervical spinal cord and the facial nerve nucleus and slight at the lumbar level. Under electron microscopy, some neurons of the lower spinal cord showed atypical inclusions. These data suggest that an unknown metabolic defect is responsible for a primary neuronopathy. Lipid accumulation in Schwann cells, resulting from fiber degeneration is probably transient, accounting for the absence of foamy cells in regions with longstanding involvement.

  15. Klippel-Feil syndrome – the risk of cervical spinal cord injury: A case report

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    Singh Gurpreet

    2002-04-01

    Full Text Available Abstract Background Klippel-Feil syndrome is defined as congenital fusion of two or more cervical vertebrae and is believed to result from faulty segmentation along the embryo's developing axis during weeks 3–8 of gestation. Persons with Klippel-Feil syndrome and cervical stenosis may be at increased risk for spinal cord injury after minor trauma as a result of hypermobility of the various cervical segments. Persons with Klippel-Feil Syndrome often have congenital anomalies of the urinary tract as well. Case presentation A 51-year male developed incomplete tetraplegia in 1997 when he slipped and fell backwards hitting his head on the floor. X-rays of cervical spine showed fusion at two levels: C2 and C3 vertebrae, and C4 and C5 vertebrae. Intravenous urography (IVU revealed no kidneys in the renal fossa on both sides, but the presence of crossed, fused renal ectopia in the left ilio-lumbar region. This patient had a similar cervical spinal cord injury about 15 years ago, when he developed transient numbness and paresis of the lower limbs following a fall. Discussion and Conclusion 1 Persons with Klippel-Feil syndrome should be made aware of the increased risk of sustaining transient neurologic deterioration after minor trauma if there is associated radiographic evidence of spinal stenosis. 2 Patients with Klippel-Feil syndrome often have congenital anomalies of the urinary tract. Our patient had crossed, fused, ectopia of kidney. 3 When patients with Klippel-Feil syndrome sustain tetraplegia they have increased chances of developing urinary tract calculi. Treatment of kidney stones may pose a challenge because of associated renal anomalies. 4 Health professionals caring for cervical spinal cord injury patients with Klippel-Feil syndrome and renal anomalies should place emphasis on prevention of kidney stones. A large fluid intake is recommended for these patients, as a high intake of fluids is still the most powerful and certainly the most

  16. Posterior Cord Syndrome and Trace Elements Deficiency as an Uncommon Presentation of Common Variable Immunodeficiency

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    Yuri Silva Macedo

    2017-01-01

    Full Text Available Diarrhea is one of the most common symptoms in common variable immunodeficiency, but neurologic manifestations are rare. We presented a 50-year-old woman with recurrent diarrhea and severe weight loss that developed a posterior cord syndrome. Endoscopy found a duodenal villous blunting, intraepithelial lymphocytosis, and lack of plasma cells and magnetic resonance imaging of the spine was normal. Laboratory assays confirmed common variable immunodeficiency syndrome and showed low levels of trace elements (copper and zinc. Treatment was initiated with parenteral replacement of trace elements and intravenous human immunoglobulin and the patient improved clinically. In conclusion, physicians must be aware that gastrointestinal and neurologic disorders may be related to each other and remember to request trace elements laboratory assessment.

  17. A risk factor analysis of outcomes after unrelated cord blood transplantation for children with Wiskott-Aldrich syndrome

    Science.gov (United States)

    Shekhovtsova, Zhanna; Bonfim, Carmem; Ruggeri, Annalisa; Nichele, Samantha; Page, Kristin; AlSeraihy, Amal; Barriga, Francisco; de Toledo Codina, José Sánchez; Veys, Paul; Boelens, Jaap Jan; Mellgren, Karin; Bittencourt, Henrique; O’Brien, Tracey; Shaw, Peter J.; Chybicka, Alicja; Volt, Fernanda; Giannotti, Federica; Gluckman, Eliane; Kurtzberg, Joanne; Gennery, Andrew R.; Rocha, Vanderson

    2017-01-01

    Wiskott-Aldrich syndrome is a severe X-linked recessive immune deficiency disorder. A scoring system of Wiskott-Aldrich syndrome severity (0.5–5) distinguishes two phenotypes: X-linked thrombocytopenia and classic Wiskott-Aldrich syndrome. Hematopoietic cell transplantation is curative for Wiskott-Aldrich syndrome; however, the use of unrelated umbilical cord blood transplantation has seldom been described. We analyzed umbilical cord blood transplantation outcomes for 90 patients. The median age at umbilical cord blood transplantation was 1.5 years. Patients were classified according to clinical scores [2 (23%), 3 (30%), 4 (23%) and 5 (19%)]. Most patients underwent HLA-mismatched umbilical cord blood transplantation and myeloablative conditioning with anti-thymocyte globulin. The cumulative incidence of neutrophil recovery at day 60 was 89% and that of grade II–IV acute graft-versus-host disease at day 100 was 38%. The use of methotrexate for graft-versus-host disease prophylaxis delayed engraftment (P=0.02), but decreased acute graft-versus-host disease (P=0.03). At 5 years, overall survival and event-free survival rates were 75% and 70%, respectively. The estimated 5-year event-free survival rates were 83%, 73% and 55% for patients with a clinical score of 2, 4–5 and 3, respectively. In multivariate analysis, age <2 years at the time of the umbilical cord blood transplant and a clinical phenotype of X-linked thrombocytopenia were associated with improved event-free survival. Overall survival tended to be better in patients transplanted after 2007 (P=0.09). In conclusion, umbilical cord blood transplantation is a good alternative option for young children with Wiskott-Aldrich syndrome lacking an HLA identical stem cell donor. PMID:28255019

  18. Metabolic syndrome in people with a long-standing spinal cord injury : associations with physical activity and capacity

    NARCIS (Netherlands)

    de Groot, Sonja; Adriaansen, Jacinthe J.; Tepper, Marga; Snoek, Govert J.; van der Woude, Lucas H. V.; Post, Marcel W. M.

    2016-01-01

    This study investigated (i) the prevalence of the metabolic syndrome (MetS) in people with a long-standing spinal cord injury (SCI); (ii) whether personal or lesion characteristics are determinants of the MetS; and (iii) the association with physical activity or peak aerobic capacity on the MetS. In

  19. Serum thyroglobulin levels in preterm infants with and without the respiratory distress syndrome. I. Cord blood study

    NARCIS (Netherlands)

    Kok, J. H.; Tegelaers, W. H.; de Vijlder, J. J.

    1986-01-01

    Cord serum levels of thyroglobulin (Tg) and thyroid stimulating hormone (TSH) in 147 term and preterm infants were related to gestation age, birth weight, respiratory distress syndrome (RDS), and several perinatal factors by means of multiple linear regression analysis. None of the perinatal factors

  20. GRASP : A Multitasking Tether

    OpenAIRE

    Catherine eRabouille; Adam eLinstedt

    2016-01-01

    Originally identified as Golgi stacking factors in vitro, the Golgi reassembly stacking protein (GRASP) family has been shown to act as membrane tethers with multiple cellular roles. As an update to previous comprehensive reviews of the GRASP family (Giuliani et al., 2011; Vinke et al., 2011; Jarvela and Linstedt, 2012), we outline here the latest findings concerning their diverse roles. New insights into the mechanics of GRASP-mediated tethering come from recent crystal structures. The model...

  1. Continuous Thoracic Sympathetic Ganglion Block in Complex Regional Pain Syndrome Patients with Spinal Cord Stimulation Implantation

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    EungDon Kim

    2016-01-01

    Full Text Available The sympathetic block is widely used for treating neuropathic pain such as complex regional pain syndrome (CRPS. However, single sympathetic block often provides only short-term effect. Moreover, frequent procedures for sympathetic block may increase the risk of complications. The use of epidural route may be limited by concern of infection in case of previous implantation of the spinal cord stimulation (SCS. In contrast, a continuous sympathetic block can be administered without such concerns. The continuous thoracic sympathetic block (TSGB has been used to treat the ischemic disease and other neuropathic conditions such as postherpetic neuralgia. We administered continuous thoracic sympathetic block using catheter in CRPS patients who underwent SCS implantations and achieved desirable outcomes. We believe a continuous sympathetic block is a considerable option before performing neurolysis or radiofrequency rhizotomy and even after SCS implantation.

  2. Guillain-Barre syndrome: A possibility in a spinal cord injured patient

    Directory of Open Access Journals (Sweden)

    Jagatsinh Yogendrasinh

    2007-01-01

    Full Text Available A 28-year-old male had paraplegia as a result of fracture dislocation of T12/L1 six years ago. He was functioning independently until four weeks ago, when he started complaining of trunkal paraesthesia which later progressed to include the upper extremities. The initial diagnosis was that of posttraumatic syringomyelia (PTS. While awaiting the MRI scan he developed weakness of upper limbs. The weakness restricted his self-care activities including transfers. The MRI did not show any evidence of syringomyelia. Neurological consultation and assessment yielded provisional diagnosis of Guillain-Barre syndrome (GBS. The patient was treated with immunoglobulins and regained 90% of his previous neurological status. This case is reported to raise awareness among clinicians to include the possibility of the GBS in the differential diagnosis of progressive neurological loss on top of existing neurological deficiency in spinal cord injured patients.

  3. Umbilical cord blood and neonatal endothelin-1 levels in preterm newborns with and without respiratory distress syndrome

    Directory of Open Access Journals (Sweden)

    A.C.W. Benjamin

    2005-09-01

    Full Text Available Increased pulmonary vascular resistance in preterm newborn infants with respiratory distress syndrome is suggested, and endothelin-1 plays an important role in pulmonary vascular reactivity in newborns. We determined umbilical cord blood and neonatal (second sample levels of endothelin-1 in 18 preterm newborns with respiratory distress syndrome who had no clinical or echocardiographic diagnosis of pulmonary hypertension and 22 without respiratory distress syndrome (gestational ages: 31.4 ± 1.6 and 29.3 ± 2.3 weeks, respectively. Umbilical cord blood and a second blood sample taken 18 to 40 h after birth were used for endothelin-1 determination by enzyme immunoassay. Median umbilical cord blood endothelin-1 levels were similar in both groups (control: 10.9 and respiratory distress syndrome: 11.4 pg/mL and were significantly higher than in the second sample (control: 1.7 pg/mL and respiratory distress syndrome: 3.5 pg/mL, P < 0.001 for both groups. Median endothelin-1 levels in the second sample were significantly higher in children with respiratory distress syndrome than in control infants (P < 0.001. There were significant positive correlations between second sample endothelin-1 and Score for Neonatal Acute Physiology and Perinatal Extension II (r = 0.36, P = 0.02, and duration of mechanical ventilation (r = 0.64, P = 0.02. A slower decline of endothelin-1 from birth to 40 h of life was observed in newborns with respiratory distress syndrome when compared to controls. A significant correlation between neonatal endothelin-1 levels and some illness-severity signs suggests that endothelin-1 plays a role in the natural course of respiratory distress syndrome in preterm newborns.

  4. Comparative biomechanical analysis of gait in patients with central cord and Brown-Séquard syndrome.

    Science.gov (United States)

    Gil-Agudo, Angel; Pérez-Nombela, Soraya; Pérez-Rizo, Enrique; del Ama-Espinosa, Antonio; Crespo-Ruiz, Beatriz; Pons, José L

    2013-01-01

    This is a pilot study with the aim to highlight the use of kinematic and kinetic analyses as an adjunct to the assessment of individual patients with central cord syndrome (CCS) and hemisection or Brown-Séquard syndrome (BSS) and to discuss their possible consequences for clinical management. The sample studied consisted of 17 patients with CCS, 13 with BSS and 20 control subjects (control group (CG)). Data were obtained using a three-dimensional motion analysis system and two force plates. Gait differences were compared between CCS, BSS walking at a self-selected speed and CG at both a self-selected and a similar speed to that of the patient groups. The most relevant findings involved the knee and ankle, especially in the sagittal plane. In patients with CCS, knee flexion at initial contact was increased with respect to those in the BSS group (p gait biomechanical analysis to detect underlying impairments can help the physician to set a specific rehabilitation program in each CCS and BSS walking patient. In this group of patients, rehabilitation treatment should aim to improve gait control and optimise ankle positioning at initial contact. Implications for Rehabilitation In this study, gait differences between patients with CSS and BSS were evaluated with biomechanical equipment. The most remarkable differences were found in the knee and ankle sagittal plane due to ankle position at initial contact. In this group of patients, rehabilitation treatment should aim to improve gait control and to get a better ankle positioning at initial contact.

  5. GRASP: A multitasking tether

    Directory of Open Access Journals (Sweden)

    Catherine eRabouille

    2016-01-01

    Full Text Available Originally identified as Golgi stacking factors in vitro, the Golgi reassembly stacking protein (GRASP family has been shown to act as membrane tethers with multiple cellular roles. As an update to previous comprehensive reviews of the GRASP family (Vinke et al., 2011 (Giuliani et al., 2011;Jarvela and Linstedt, 2012, we outline here the latest findings concerning their diverse roles. New insights into the mechanics of GRASP-mediated tethering come from recent crystal structures. The models of how GRASP65 and GRASP55 tether membranes relate directly to their role in Golgi ribbon formation in mammalian cells and the unlinking of the ribbon at the onset of mitosis. However, it is also clear that GRASPs act outside the Golgi with roles at the ER and ER exit sites (ERES. Furthermore, the proteins of this family display other roles upon cellular stress, especially in mediating unconventional secretion of both transmembrane proteins (Golgi bypass and cytoplasmic proteins (through secretory autophagosomes.

  6. GRASP: A Multitasking Tether.

    Science.gov (United States)

    Rabouille, Catherine; Linstedt, Adam D

    2016-01-01

    Originally identified as Golgi stacking factors in vitro, the Golgi reassembly stacking protein (GRASP) family has been shown to act as membrane tethers with multiple cellular roles. As an update to previous comprehensive reviews of the GRASP family (Giuliani et al., 2011; Vinke et al., 2011; Jarvela and Linstedt, 2012), we outline here the latest findings concerning their diverse roles. New insights into the mechanics of GRASP-mediated tethering come from recent crystal structures. The models of how GRASP65 and GRASP55 tether membranes relate directly to their role in Golgi ribbon formation in mammalian cells and the unlinking of the ribbon at the onset of mitosis. However, it is also clear that GRASPs act outside the Golgi with roles at the ER and ER exit sites (ERES). Furthermore, the proteins of this family display other roles upon cellular stress, especially in mediating unconventional secretion of both transmembrane proteins (Golgi bypass) and cytoplasmic proteins (through secretory autophagosomes).

  7. Modelling Tethered Enzymatic Reactions

    Science.gov (United States)

    Solis Salas, Citlali; Goyette, Jesse; Coker-Gordon, Nicola; Bridge, Marcus; Isaacson, Samuel; Allard, Jun; Maini, Philip; Dushek, Omer

    Enzymatic reactions are key to cell functioning, and whilst much work has been done in protein interaction in cases where diffusion is possible, interactions of tethered proteins are poorly understood. Yet, because of the large role cell membranes play in enzymatic reactions, several reactions may take place where one of the proteins is bound to a fixed point in space. We develop a model to characterize tethered signalling between the phosphatase SHP-1 interacting with a tethered, phosphorylated protein. We compare our model to experimental data obtained using surface plasmon resonance (SPR). We show that a single SPR experiment recovers 5 independent biophysical/biochemical constants. We also compare the results between a three dimensional model and a two dimensional model. The work gives the opportunity to use known techniques to learn more about signalling processes, and new insights into how enzyme tethering alters cellular signalling. With support from the Mexican Council for Science and Technology (CONACyT), the Public Education Secretariat (SEP), and the Mexican National Autonomous University's Foundation (Fundacion UNAM).

  8. GRASP : A Multitasking Tether

    NARCIS (Netherlands)

    Rabouille, Catherine; Linstedt, Adam D

    2016-01-01

    Originally identified as Golgi stacking factors in vitro, the Golgi reassembly stacking protein (GRASP) family has been shown to act as membrane tethers with multiple cellular roles. As an update to previous comprehensive reviews of the GRASP family (Giuliani et al., 2011; Vinke et al., 2011;

  9. Electrodynamic Tethers for Spacecraft Propulsion

    Science.gov (United States)

    Johnson, Les

    2009-01-01

    Electrodynamic (Drag) Tether Thrust Principles: a) Uses both solar energy and consumes no propellant. b) Tether's orbital velocity v (approx. 7500 m/s) through North-pointing geomagnetic field B(sub north) (0.18 - 0.32 Gauss) induces voltage (35 - 160 V/km) in tether. c) Return current is through surrounding plasma. d) Current I produces a drag thrust force F on the tether. e) Magnetic force F from current I through insulated tether of length l: F = lI x B(sub north).

  10. A Clinical Practice Guideline for the Management of Patients With Acute Spinal Cord Injury and Central Cord Syndrome: Recommendations on the Timing (≤24 Hours Versus >24 Hours) of Decompressive Surgery

    Science.gov (United States)

    Tetreault, Lindsay A.; Wilson, Jefferson R.; Aarabi, Bizhan; Anderson, Paul; Arnold, Paul M.; Brodke, Darrel S.; Burns, Anthony S.; Chiba, Kazuhiro; Dettori, Joseph R.; Furlan, Julio C.; Hawryluk, Gregory; Holly, Langston T.; Howley, Susan; Jeji, Tara; Kalsi-Ryan, Sukhvinder; Kotter, Mark; Kurpad, Shekar; Marino, Ralph J.; Martin, Allan R.; Massicotte, Eric; Merli, Geno; Middleton, James W.; Nakashima, Hiroaki; Nagoshi, Narihito; Palmieri, Katherine; Singh, Anoushka; Skelly, Andrea C.; Tsai, Eve C.; Vaccaro, Alexander; Yee, Albert; Harrop, James S.

    2017-01-01

    Objective: To develop recommendations on the timing of surgical decompression in patients with traumatic spinal cord injury (SCI) and central cord syndrome. Methods: A systematic review of the literature was conducted to address key relevant questions. A multidisciplinary guideline development group used this information, along with their clinical expertise, to develop recommendations for the timing of surgical decompression in patients with SCI and central cord syndrome. Based on GRADE, a strong recommendation is worded as “we recommend,” whereas a weak recommendation is presented as “we suggest.” Results: Conclusions from the systematic review included (1) isolated studies reported statistically significant and clinically important improvements following early decompression at 6 months and following discharge from inpatient rehabilitation; (2) in one study on acute central cord syndrome without instability, a marginally significant improvement in total motor scores was reported at 6 and 12 months in patients managed with early versus late surgery; and (3) there were no significant differences in length of acute care/rehabilitation stay or in rates of complications between treatment groups. Our recommendations were: “We suggest that early surgery be considered as a treatment option in adult patients with traumatic central cord syndrome” and “We suggest that early surgery be offered as an option for adult acute SCI patients regardless of level.” Quality of evidence for both recommendations was considered low. Conclusions: These guidelines should be implemented into clinical practice to improve outcomes in patients with acute SCI and central cord syndrome by promoting standardization of care, decreasing the heterogeneity of management strategies, and encouraging clinicians to make evidence-informed decisions. PMID:29164024

  11. Spinal cord stimulation in adolescents with complex regional pain syndrome type I (CRPS-I).

    Science.gov (United States)

    Olsson, Gunnar L; Meyerson, Björn A; Linderoth, Bengt

    2008-01-01

    Complex regional pain syndrome type I (CRPS-I) is not uncommon in children, particularly in adolescent girls. Most often, the condition involves a foot and is characterized by spontaneous pain, tactile allodynia and dysautonomic signs. There is usually a history of a minor, local trauma but sometimes no reasonable cause can be identified, and there are no signs of persistent tissue injury giving rise to ongoing nociception. Common analgesics are generally of no benefit, and the standard treatment includes sociopsychological support, physiotherapy, tricyclic antidepressants and antiepileptic drugs, sympathetic blocks (SB), and cognitive-behavioural therapy. For a minority of patients who prove to be resistant to such therapies, spinal cord stimulation (SCS) may be tried. The present study comprises seven girls, 11-14 years of age, presenting with severe, incapacitating and therapy-resistant CRPS-I, who were subjected to SCS. In two of them, percutaneous electrode implantation had to be performed in general anaesthesia. Trial stimulation was performed in all, but one. In two cases, it was not possible to produce paraesthesias that entirely covered the pain area. A pain relieving effect of SCS was usually not reported until after 1-2 weeks of trial stimulation. After another 2-6 weeks, pain alleviation was complete in five of the seven patients, one to eight years after the intervention. In one case, a local infection necessitated the removal of the electrode; nevertheless a few days of trial stimulation produced substantial pain relief that still persists. In four patients, the SCS use was gradually diminished and eventually the device could be removed. The favourable outcome in all seven cases with no or minor remaining symptoms and without severe recurrences illustrates that SCS may also be an efficient treatment in paediatric cases with exceptionally therapy resistant forms of CRPS I.

  12. Establishing Minimal Clinically Important Difference of Spinal Cord Stimulation Therapy in Post-Laminectomy Syndrome.

    Science.gov (United States)

    Paul, Alexandra R; Kumar, Vignessh; Roth, Steven; Gooch, M Reid; Pilitsis, Julie G

    2017-12-01

    The concept of minimum clinically important difference (MCID) has been shown to be effective in spine surgery to differentiate between clinically insignificant and significant improvements as determined by the patient. The MCID for spinal cord stimulation (SCS) to date has not been established. We sought to determine the MCID for SCS therapy for failed laminectomy syndromes. Preoperative and 6-mo outcomes were assessed prospectively, including the Oswestry Disability Index (ODI), Beck Depression Inventory (BDI), and McGill and Visual Analog Survey questionnaires. Patients were asked: (1) are you satisfied with SCS therapy and (2) would you have the surgery again. Four methods of calculating the MCID were utilized. Forty-eight patients who underwent placement of an SCS between 2012 and 2014 were reviewed. The 4 calculation methods yielded a range of outcome scores (ODI 8.2-13.3, BDI 3.2-7, McGill 0.3-1.3, and Visual Analog Scale [VAS] 1.2-3.7). The maximum area under the curve was observed for the ODI, BDI, and VAS (0.73, 0.81, and 0.89, respectively), which signifies acceptable accuracy in distinguishing responders from nonresponders with the receiver operating characteristic method and suggests that VAS may be the most sensitive in determining meaningful change for the patient. The MCID for SCS placement was calculated using 4 different methods. The results are similar to calculations for the MCID for many lumbar and cervical procedures done for pain. Our results suggest that an improvement of 1.2 to 3.7 points on the VAS scale and 8.2 to 13.3 points on the ODI is clinically meaningful to the patient. Further defining the MCID for SCS therapy will remain of utmost importance in order to justify the cost of the procedure.

  13. Electrodynamic Tethers for Spacecraft Propulsion

    Science.gov (United States)

    Johnson, Les; Estes, Robert D.; Lorenzini, Enrico; Martinez-Sanchez, Manuel; Sanmartin, Juan; Vas, Irwin

    1998-01-01

    Relatively short electrodynamic tethers can use solar power to 'push' against a planetary magnetic field to achieve propulsion without the expenditure of propellant. The groundwork has been laid for this type of propulsion. NASA began developing tether technology for space applications in the 1960's. Important recent milestones include retrieval of a tether in space (TSS-1, 1992), successful deployment of a 20-km-long tether in space (SEDS-1, 1993), and operation of an electrodynamic tether with tether current driven in both directions-power and thrust modes (PMG, 1993). The planned Propulsive Small Expendable Deployer System (ProSEDS) experiment will demonstrate electrodynamic tether thrust during its flight in early 2000. ProSEDS will use the flight-proven Small Expendable Deployer System (SEDS) to deploy a 5 km bare copper tether from a Delta II upper stage to achieve approximately 0.4 N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of the endmass collector and insulated tether approach used on previous missions. Theory and ground-based plasma chamber testing indicate that the bare tether is a highly-efficient current collector. The flight experiment is a precursor to utilization of the technology on the International Space Station for reboost application and the more ambitious electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes - all using electrodynamic thrust. In addition, the use of this type of propulsion may be attractive for future missions at Jupiter and any other planetary body with a magnetosphere.

  14. Small for Gestational Age and Magnesium in Cord Blood Platelets: Intrauterine Magnesium Deficiency May Induce Metabolic Syndrome in Later Life

    Directory of Open Access Journals (Sweden)

    Junji Takaya

    2011-01-01

    Full Text Available Magnesium deficiency in pregnancy frequently occurs because of inadequate or low intake of magnesium. Magnesium deficiency during pregnancy can induce not only maternal and fetal nutritional problems, but also consequences that might last in offspring throughout life. Many epidemiological studies have disclosed that small for gestational age (SGA is associated with an increased risk of insulin resistance in adult life. We reported that intracellular magnesium of cord blood platelets is lower in SGA groups than that in appropriate for gestational age groups, suggesting that intrauterine magnesium deficiency may result in SGA. Taken together, intrauterine magnesium deficiency in the fetus may lead to or at least program insulin resistance after birth. In this review, we propose that intrauterine magnesium deficiency may induce metabolic syndrome in later life. We discuss the potential contribution of aberrant magnesium regulation to SGA and to the pathogenesis of metabolic syndrome.

  15. Sertoli cell tumors associated with feminizing syndrome and spermatic cord torsion in two cryptorchid dogs

    OpenAIRE

    QUARTUCCIO, Marco; MARINO*, Gabriele; Garufi, Giuseppe; Cristarella, Santo; Zanghì, Antonina

    2012-01-01

    The association of cryptorchidism, functional Sertoli cell tumors, and spermatic cord torsion has been rarely reported in the literature. Two dogs were admitted for bilateral skin alopecia and weight loss. Both animals were cryptorchid and displayed a pendulous preputial sheath, prostate hypertrophy, and increased levels of circulating oestrogen. Transabdominal palpation and ultrasonography revealed the presence of neoplastic retained gonads. During surgery, spermatic cord torsion was also de...

  16. Successful management of aortic thrombi resulting in spinal cord infarction in a patient with antiphospholipid antibody syndrome and acute cholecystitis

    Directory of Open Access Journals (Sweden)

    Izumi M

    2011-12-01

    Full Text Available Manabu Izumi, Shoko Teraoka, Keisuke Yamashita, Kenji Matsumoto, Tomohiro Muronoi, Yoshimitsu Izawa, Chikara Yonekawa, Masaki Ano, Masayuki SuzukawaDepartment of Emergency and Critical Care Medicine, Jichi Medical University, Tochigi, JapanAbstract: A 74-year-old man with coronary artery disease was suffering from acute nonobstructive cholecystitis and was admitted to a nearby hospital. Dual antiplatelet (aspirin and ticlopidine therapy was discontinued before preparation for surgical resection of the gall bladder. During his time in hospital he was aware of lumbar pain and weakness in both legs. He was transferred to our hospital for further evaluation and therapy. Diffuse intra-aortic thrombi were revealed by computed tomography with contrast media, and magnetic resonance imaging showed spinal cord infarction. However, computed tomography scans of the descending aorta obtained 4 months before admission exhibited no signs of atherosclerotic plaques or intra-aortic thrombi. Laboratory data suggest that antiphospholipid antibody syndrome might have caused these acute multiple intra-arterial thrombi. By restarting dual antiplatelet therapy and increasing the dose of heparin (from 10,000 IU/day to 15,000 IU/day we successfully managed the patient's clinical condition and symptoms. It is important to understand that stopping antiplatelet therapy may rapidly grow thrombi in patients with a hypercoagulative state.Keywords: intra-aortic thrombus, antiphospholipid antibody syndrome, spinal cord infarction

  17. Space Station tethered elevator system

    Science.gov (United States)

    Haddock, Michael H.; Anderson, Loren A.; Hosterman, K.; Decresie, E.; Miranda, P.; Hamilton, R.

    1989-01-01

    The optimized conceptual engineering design of a space station tethered elevator is presented. The tethered elevator is an unmanned, mobile structure which operates on a ten-kilometer tether spanning the distance between Space Station Freedom and a platform. Its capabilities include providing access to residual gravity levels, remote servicing, and transportation to any point along a tether. The report discusses the potential uses, parameters, and evolution of the spacecraft design. Emphasis is placed on the elevator's structural configuration and three major subsystem designs. First, the design of elevator robotics used to aid in elevator operations and tethered experimentation is presented. Second, the design of drive mechanisms used to propel the vehicle is discussed. Third, the design of an onboard self-sufficient power generation and transmission system is addressed.

  18. Modeling and Control of a Tethered Rotorcraft

    Science.gov (United States)

    2010-07-30

    compared to the tether sway and surge . This report models the tether using a chain of N bodies connected by spherical joints rather than using stiff...tether drag coefficient CS = tether damping coefficient Cv = viscous damping coefficient d = diameter of the tether En = n x n identity matrix FA...viscous damper with damping coefficient Cv. Visco-elastic line force is written in terms of components Δx, Δy, and Δz, of the difference vector formed

  19. A Comprehensive Outcome-Specific Review of the Use of Spinal Cord Stimulation for Complex Regional Pain Syndrome.

    Science.gov (United States)

    Visnjevac, Ognjen; Costandi, Shrif; Patel, Bimal A; Azer, Girgis; Agarwal, Priya; Bolash, Robert; Mekhail, Nagy A

    2017-04-01

    Complex regional pain syndrome (CRPS) is a painful, debilitating affliction that is often difficult to treat. It has become common international practice to use spinal cord stimulation (SCS) for the treatment of CRPS as other therapies fail to provide adequate relief, quality of life, or improvement in function. This comprehensive outcome-specific systematic review of the use of SCS for CRPS was performed to elucidate the available evidence with focus on clinically relevant patient-specific outcomes. A systematic review of the literature was conducted to evaluate the effects of SCS on patients with CRPS for the following outcomes and provide summary levels of evidence in regard to each outcome: perceived pain relief, pain score, resolution of CRPS signs, functional status, quality of life, psychological impact, sleep hygiene, analgesic medication utilization, and patient satisfaction with SCS therapy. Search terms included "complex regional pain syndrome," "spinal cord stimulation," and "reflex sympathetic dystrophy," without restriction of language, date, or type of publication, albeit only original data were included in analyses. Of 30 studies selected, seven systematic reviews were excluded, as were four studies reporting combination therapy that included SCS and other therapies (ie, concurrent peripheral nerve stimulation, intrathecal therapy) without clear delineation to the effect of SCS alone on outcomes. A total of 19 manuscripts were evaluated. Perceived pain relief, pain score improvement, quality of life, and satisfaction with SCS were all rated 1B+, reflecting positive high-level (randomized controlled trial) evidence favoring SCS use for the treatment of CRPS. Evidence for functional status improvements and psychological effects of SCS was inconclusive, albeit emanating from a randomized controlled trial (evidence level 2B±), and outcomes evidence for both sleep hygiene and resolution of CRPS signs was either nonexistent or of too low quality from

  20. Experiments and simulation of a net closing mechanism for tether-net capture of space debris

    Science.gov (United States)

    Sharf, Inna; Thomsen, Benjamin; Botta, Eleonora M.; Misra, Arun K.

    2017-10-01

    This research addresses the design and testing of a debris containment system for use in a tether-net approach to space debris removal. The tether-net active debris removal involves the ejection of a net from a spacecraft by applying impulses to masses on the net, subsequent expansion of the net, the envelopment and capture of the debris target, and the de-orbiting of the debris via a tether to the chaser spacecraft. To ensure a debris removal mission's success, it is important that the debris be successfully captured and then, secured within the net. To this end, we present a concept for a net closing mechanism, which we believe will permit consistently successful debris capture via a simple and unobtrusive design. This net closing system functions by extending the main tether connecting the chaser spacecraft and the net vertex to the perimeter and around the perimeter of the net, allowing the tether to actuate closure of the net in a manner similar to a cinch cord. A particular embodiment of the design in a laboratory test-bed is described: the test-bed itself is comprised of a scaled-down tether-net, a supporting frame and a mock-up debris. Experiments conducted with the facility demonstrate the practicality of the net closing system. A model of the net closure concept has been integrated into the previously developed dynamics simulator of the chaser/tether-net/debris system. Simulations under tether tensioning conditions demonstrate the effectiveness of the closure concept for debris containment, in the gravity-free environment of space, for a realistic debris target. The on-ground experimental test-bed is also used to showcase its utility for validating the dynamics simulation of the net deployment, and a full-scale automated setup would make possible a range of validation studies of other aspects of a tether-net debris capture mission.

  1. Anchoring a Leviathan: How the Nuclear Membrane Tethers the Genome

    Directory of Open Access Journals (Sweden)

    Rafal eCzapiewski

    2016-05-01

    Full Text Available It is well established that the nuclear envelope has many distinct direct connections to chromatin that contribute to genome organization. The functional consequences of genome organization on gene regulation are less clear. Even less understood is how interactions of lamins and nuclear envelope transmembrane proteins (NETs with chromatin can produce anchoring tethers that can withstand the physical forces of and on the genome. Chromosomes are the largest molecules in the cell, making megadalton protein structures like the nuclear pore complexes and ribosomes seem small by comparison. Thus to withstand strong forces from chromosome dynamics an anchoring tether is likely to be much more complex than a single protein-protein or protein-DNA interaction. Here we will briefly review known NE-genome interactions that likely contribute to spatial genome organization, postulate in the context of experimental data how these anchoring tethers contribute to gene regulation, and posit several hypotheses for the physical nature of these tethers that need to be investigated experimentally. Significantly, disruption of these anchoring tethers and the subsequent consequences for gene regulation could explain how mutations in nuclear envelope proteins cause diseases ranging from muscular dystrophy to lipodystrophy to premature ageing progeroid syndromes. The two favored hypotheses for nuclear envelope protein involvement in disease are 1 weakening nuclear and cellular mechanical stability, and 2 disrupting genome organization and gene regulation. Considerable experimental support has been obtained for both. The integration of both mechanical and gene expression defects in the disruption of anchoring tethers could provide a unifying hypothesis consistent with both.

  2. Enabling Tethered Exploration on Mars Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Strong science motivations exist for exploring hard to reach terrain on Mars and the leading systems proposed to do so require tethers. While tethers are used...

  3. Vocal cord collapse during phrenic nerve-paced respiration in congenital central hypoventilation syndrome [v1; ref status: indexed, http://f1000r.es/Sh1pwj

    Directory of Open Access Journals (Sweden)

    Mark C Domanski

    2012-11-01

    Full Text Available Objective: Phrenic nerve pacing can be used to treat congenital central hypoventilation syndrome (CCHS. We report how the lack of normal vocal cord tone during phrenic paced respiration can result in passive vocal cord collapse and produce obstructive symptoms. Methods: We describe a case of passive vocal cord collapse during phrenic nerve paced respiration in a patient with CCHS. As far as we know, this is the first report of this etiology of airway obstruction. The patient, a 7-year-old with CCHS and normal waking vocal cord movement, continued to require nightly continuous positive airway pressure (CPAP despite successful utilization of phrenic nerve pacers. On direct laryngoscopy, the patient’s larynx was observed while the diaphragmatic pacers were sequentially engaged. Results: No abnormal vocal cord stimulation was witnessed during engaging of either phrenic nerve stimulator. However, the lack of normal inspiratory vocal cord abduction during phrenic nerve-paced respiration resulted in vocal cord collapse and partial obstruction due to passive adduction of the vocal cords through the Bernoulli effect. Bilateral phrenic nerve stimulation resulted in more vocal cord collapse than unilateral stimulation. Conclusions: The lack of vocal cord abduction on inspiration presents a limit to phrenic nerve pacers.

  4. Spinal cord stimulation for complex regional pain syndrome type 1 with dystonia: a case report and discussion of the literature

    Science.gov (United States)

    Voet, Caroline; le Polain de Waroux, Bernard; Forget, Patrice; Deumens, Ronald; Masquelier, Etienne

    2014-01-01

    Background: Complex Regional Pain Syndrome type 1 (CRPS-1) is a debilitating chronic pain disorder, the physiopathology of which can lead to dystonia associated with changes in the autonomic, central and peripheral nervous system. An interdisciplinary approach (pharmacological, interventional and psychological therapies in conjunction with a rehabilitation pathway) is central to progress towards pain reduction and restoration of function. Aim: This case report aims to stimulate reflection and development of mechanism-based therapeutic strategies concerning CRPS associated with dystonia. Case description: A 31 year old female CRPS-1 patient presented with dystonia of the right foot following ligamentoplasty for chronic ankle instability. She did not have a satisfactory response to the usual therapies. Multiple anesthetic blocks (popliteal, epidural and intrathecal) were not associated with significant anesthesia and analgesia. Mobilization of the foot by a physiotherapist was not possible. A multidisciplinary approach with psychological support, physiotherapy and spinal cord stimulation (SCS) brought pain relief, rehabilitation and improvement in the quality of life. Conclusion: The present case report demonstrates the occurrence of multilevel (peripheral and central) pathological modifications in the nervous system of a CRPS-1 patient with dystonia. This conclusion is based on the patient’s pain being resistant to anesthetic blocks at different levels and the favourable, at least initially, response to SCS. The importance of the bio-psycho-social model is also suggested, permitting behavioural change. PMID:25254100

  5. Spinal Cord Stimulation in Failed Back Surgery Syndrome: Effects on Posture and Gait—A Preliminary 3D Biomechanical Study

    Directory of Open Access Journals (Sweden)

    L. Brugliera

    2017-01-01

    Full Text Available We studied 8 patients with spinal cord stimulation (SCS devices which had been previously implanted to treat neuropathic chronic pain secondary to Failed Back Surgery Syndrome. The aim of our study was to investigate the effects of SCS on posture and gait by means of clinical scales (Short Form Health Survey-36, Visual Analogue Scale for pain, and Hamilton Depression Rating Scale and instrumented evaluation with 3D Gait Analysis using a stereophotogrammetric system. The latter was performed with the SCS device turned both OFF and ON. We recorded gait and posture using the Davis protocol and also trunk movement during flexion-extension on the sagittal plane, lateral bending on the frontal plane, and rotation on the transversal plane. During and 30 minutes after the stimulation, not only the clinical scales but also spatial-temporal gait parameters and trunk movements improved significantly. Improvement was not shown under stimulation-OFF conditions. Our preliminary data suggest that SCS has the potential to improve posture and gait and to provide a window of pain-free opportunity to optimize rehabilitation interventions.

  6. Spinal Cord Stimulation in Failed Back Surgery Syndrome: Effects on Posture and Gait—A Preliminary 3D Biomechanical Study

    Science.gov (United States)

    Brugliera, L.; De Luca, A.; Corna, S.; Bertolotto, M.; Checchia, G. A.; Cioni, M.; Lentino, C.

    2017-01-01

    We studied 8 patients with spinal cord stimulation (SCS) devices which had been previously implanted to treat neuropathic chronic pain secondary to Failed Back Surgery Syndrome. The aim of our study was to investigate the effects of SCS on posture and gait by means of clinical scales (Short Form Health Survey-36, Visual Analogue Scale for pain, and Hamilton Depression Rating Scale) and instrumented evaluation with 3D Gait Analysis using a stereophotogrammetric system. The latter was performed with the SCS device turned both OFF and ON. We recorded gait and posture using the Davis protocol and also trunk movement during flexion-extension on the sagittal plane, lateral bending on the frontal plane, and rotation on the transversal plane. During and 30 minutes after the stimulation, not only the clinical scales but also spatial-temporal gait parameters and trunk movements improved significantly. Improvement was not shown under stimulation-OFF conditions. Our preliminary data suggest that SCS has the potential to improve posture and gait and to provide a window of pain-free opportunity to optimize rehabilitation interventions. PMID:29147083

  7. Multigenerational pedigree with STAR syndrome: A novel FAM58A variant and expansion of the phenotype.

    Science.gov (United States)

    Boczek, Nicole J; Kruisselbrink, Teresa; Cousin, Margot A; Blackburn, Patrick R; Klee, Eric W; Gavrilova, Ralitza H; Lanpher, Brendan C

    2017-05-01

    STAR syndrome is a rare X-linked dominant disorder characterized by toe Syndactyly, Telecanthus, Anogenital malformations, and Renal malformations, and is caused by loss-of-function variants in FAM58A. Our proband presented with the hallmark features of STAR syndrome, as well as some additional less typical features including tethered cord and hearing loss. The proband's mother and maternal half-sister had similar clinical histories, but had variability in phenotypic severity. Clinical whole exome sequencing revealed a novel pathogenic nonsense variant, c.651G>A (p.Trp217X; NM_152274), in FAM58A in the proband, mother, and maternal half-sister. This pedigree represents the 11-13th patients described with STAR syndrome and the third instance of familial inheritance. To our knowledge, this is the first occurrence of a nonsense variant in FAM58A described in individuals with STAR syndrome and the phenotype in this pedigree suggests that tethered cord and hearing loss are features of STAR syndrome. © 2017 Wiley Periodicals, Inc.

  8. Central cord injury: pathophysiology, management, and outcomes.

    Science.gov (United States)

    Harrop, James S; Sharan, Ashwini; Ratliff, Jonathon

    2006-01-01

    Cervical spinal trauma can result in a heterogeneous collection of spinal cord injury syndromes. Acute traumatic central cord syndrome is a common category of which no uniform consensus on the etiology, pathophysiology, and treatment exists. To evaluate and review potential pathophysiology, current treatment options, and management of central cord injuries. Comprehensive literature review and clinical experience. A systematic review of Medline for articles related to central cord and spinal cord injury was conducted up to and including journal articles published in September 2005. Central cord injuries is a clinical definition which is composed of a heterogeneous population for which medical management and surgical decompression and stabilization provide improved neurologic recovery.

  9. Comparison of the metabolic parameters and androgen level of umbilical cord blood in newborns of mothers with polycystic ovary syndrome and controls

    Directory of Open Access Journals (Sweden)

    Ferdous Mehrabian

    2012-01-01

    Full Text Available Background: This study aimed to assess the metabolic parameters and androgen concentration in the cord blood of newborns of mothers with polycystic ovary syndrome (PCOS in comparison with controls. Materials and Methods: This cross-sectional study was conducted in 2010-2011 in Isfahan, Iran. Biochemical tests were conducted on 40 infants, born from singleton pregnancies in women with PCOS and an equal number of controls. Results: The mean weight gain during pregnancy was higher in women with PCOS than in controls (16.02 ± 4.39 vs. 9.10 ± 2.20 kg, respectively, P < 0.0001. The mean birth weight was lower in newborns of mothers with PCOS than in controls (2905.25 ± 415.59 vs. 3223.25 ± 425.02 vs. grams, respectively, P = 0.001. The mean testosterone was higher in cord blood of newborns of PCOS women than in controls (5.58 ± 3.20 vs. 2.28 ± 0.62 pg/ml, P < 0.0001. Triglycerides and LDL-C were lower in cord blood of newborns, born from PCOS women than in controls (P = 0.001. The birth weight of the newborns of PCOS mothers was negatively correlated to free testosterone of cord blood (R = -0. 26, P = 0.04. Conclusion: The metabolic aberration in PCOS might influence fetal birth weight and cord blood lipid profile. These disorders may be caused by an exposure to elevated testosterone level during fetal life. The offspring of PCOS women may be at higher risk for chronic diseases in later life. The clinical impact of our findings should be confirmed in future longitudinal studies.

  10. Spinal cord stimulation for failed back surgery syndrome: a decision-analytic model and cost-effectiveness analysis.

    Science.gov (United States)

    Taylor, Rebecca J; Taylor, Rod S

    2005-01-01

    The aim of this study was to develop a decision-analytic model to assess the cost-effectiveness of spinal cord stimulation (SCS), relative to nonsurgical conventional medical management (CMM), for patients with failed back surgery syndrome (FBSS). A decision tree and Markov model were developed to synthesize evidence on both health-care costs and outcomes for patients with FBSS. Outcome data of SCS and CMM were sourced from 2-year follow-up data of two randomized controlled trials (RCTs). Treatment effects were measured as levels of pain relief. Short- and long-term health-care costs were obtained from a detailed Canadian costing study in FBSS patients. Results are presented as incremental cost per quality adjusted life year (QALY) and expressed in 2003 Euros. Costs were discounted at 6 percent and outcomes at 1.5 percent. Over the lifetime of the patient, SCS was dominant (i.e., SCS is cost-saving and gives more health gain relative to CMM); a finding that was robust across sensitivity analyses. At a 2-year time horizon, SCS gave more health gain but at an increased cost relative to CMM. Given the uncertainty in effectiveness and cost parameters, the 2-year cost-effectiveness of SCS ranged from 30,370 Euros in the base case to 63,511 Euros in the worst-case scenario. SCS was found to be both more effective and less costly than CMM, over the lifetime of a patient. In the short-term, although SCS is potentially cost-effective, the model results are highly sensitive to the choice of input parameters. Further empirical data are required to improve the precision in the estimation of short-term cost-effectiveness.

  11. Unilateral Vocal Cord Paralysis following Insertion of a Supreme Laryngeal Mask in a Patient with Sjögren’s Syndrome

    Directory of Open Access Journals (Sweden)

    T. O. J. Masarwa

    2016-01-01

    Full Text Available Since its introduction in 1988 by Dr. Archie Brain, the laryngeal mask airway (LMA is being used with increasing frequency. Its ease of use has made it a very popular device in airway management and compared to endotracheal intubation it is less invasive. The use of LMA was on the rise, so has been the incidence of its related complications. We report severe unilateral vocal cord paralysis following the use of the supreme laryngeal mask (sLMA in a patient with Sjögren’s syndrome. In addition, we propose possible mechanisms of injury, review the existing case reports, and discuss our findings.

  12. Spinal Cord Stimulation

    DEFF Research Database (Denmark)

    Meier, Kaare

    2014-01-01

    Spinal cord stimulation (SCS) is a surgical treatment for chronic neuropathic pain that is refractory to other treatment. Originally described by Shealy et al. in 1967(1), it is used to treat a range of conditions such as complex regional pain syndrome (CRPS I)(2), angina pectoris(3), radicular...... pain after failed back surgery syndrome (FBSS)(4), pain due to peripheral nerve injury, stump pain(5), peripheral vascular disease(6) and diabetic neuropathy(7,8); whereas phantom pain(9), postherpetic neuralgia(10), chronic visceral pain(11), and pain after partial spinal cord injury(12) remain more...

  13. Microstructure of the Midbrain and Cervical Spinal Cord in Idiopathic Restless Legs Syndrome: A Diffusion Tensor Imaging Study.

    Science.gov (United States)

    Lindemann, Klaas; Müller, Hans-Peter; Ludolph, Albert C; Hornyak, Magdolna; Kassubek, Jan

    2016-02-01

    Diffusion tensor imaging (DTI) allows the study of white matter microstructure in the central nervous system. The aim of this study was to examine the DTI metrics of the cervical spinal cord and the brainstem up to the midbrain in patients with idiopathic restless legs (RLS) compared to matched healthy controls. DTI analysis of the cervical spinal cord and the brainstem up into the midbrain was performed in 25 patients with idiopathic RLS and 25 matched healthy controls. Data analysis in the brain was performed by voxelwise comparison of fractional anisotropy (FA) maps at group level. Cervical spinal cord data analysis was performed by slicewise analysis of averaged FA values in axial slices along the spinal cord. Voxelwise comparison of FA maps in the brainstem showed significant microstructural alterations in two clusters in the midbrain bilaterally. Slicewise comparison of the FA maps in the cervical spinal cord showed a trend for lower FA values at the level of the second and third vertebra area in the patient sample. The imaging data suggest that significant alterations in the midbrain in RLS can be visualized by DTI and might correlate to a macroscopically subtle process with changes of the tissue microstructure in the corresponding tracts. An additional area of interest is regionally clustered in the upper cervical spinal cord with a tendency toward altered diffusion metrics. These results might be addressed by further studies, e.g., at higher magnetic field strengths. © 2016 Associated Professional Sleep Societies, LLC.

  14. Tether dynamics and control results for tethered satellite system's initial flight

    Science.gov (United States)

    Chapel, Jim D.; Flanders, Howard

    The recent Tethered Satellite System-1 (TSS-1) mission has provided a wealth of data concerning the dynamics of tethered systems in space and has demonstrated the effectiveness of operational techniques designed to control these dynamics. In this paper, we review control techniques developed for managing tether dynamics, and discuss the results of using these techniques for the Tethered Satellite System's maiden flight on STS-46. In particular, the flight results of controlling libration dynamics, string dynamics, and slack tether are presented. These results show that tether dynamics can be safely managed. The overall stability of the system was found to be surprisingly good even at relatively short tether lengths. In fact, the system operated in passive mode at a tether length of 256 meters for over 9 hours. Only monitoring of the system was required during this time. Although flight anomalies prevented the planned deployment to 20 km, the extended operations at shorter tether lengths have proven the viability of using tethers in space. These results should prove invaluable in preparing for future missions with tethered objects in space.

  15. Hypervelocity impact experiments on tether materials

    Science.gov (United States)

    Sabath, D.; Paul, K. G.

    Tethered systems are new and exciting means for various applications, such as the re-entry of small payloads from the space station. Due to payload mass constraints of the launch vehicle, the mass of the tethered system should be minimised. Therefore, fibres are the choice for tether materials. The probability of a severe impact into the tether is very high due its large surface area despite its small diameter. Hence, the risk of an impact of a micrometeoroid or a space debris particle cutting the tether should be investigated prior to flight. This work reports first observations of hypervelocity impact experiments on three different braided materials used for tether applications. The tether samples -- Dyneema, Kevlar and Spectra -- were tested using the plasma drag accelerator (PDA) facility of the Fachgebiet Raumfahrttechnik (LRT), Technische Universität München (TUM). An overview of the morphology of such impacts is presented. The extent of damage is compared to other materials commonly found on spacecraft. A risk assessment of an impact cutting the tether with current meteoroid and debris models and data from LDEF, Eureca and HST solar arrays, is also given.

  16. Modeling and position control of tethered octocopters

    Directory of Open Access Journals (Sweden)

    de Castro Davi Ferreira

    2016-01-01

    Full Text Available This work presents the modeling and control of a multirotor aerial vehicle with tethered configuration. It is considered an octocopter with a saturated proportional-plus-derivative position control. A viscoelastic model is considered for the tether, which has a tension control. Numerical simulations are carried out to compare the performance of the tethred configuration with the vehicle in free flight.

  17. Mobile tethering: Overview, perspectives and challengess

    NARCIS (Netherlands)

    Constantinescu, M.; Onur, E.; Durmus, Y.; Nikou, S.; Reuver, M. de; Bouwman, H.; Djurica, M.; Glatz, P.M.

    2014-01-01

    Purpose: The purpose of this paper is to analyze mobile tethering from technological and social perspectives. Mobile tethering allows us to share cellular data connection with others over WiFi, Bluetooth or USB. Although the technology is ready and has promising outcomes, service providers and the

  18. Intrauterine Reprogramming of the Polycystic Ovary Syndrome: Evidence from a Pilot Study of Cord Blood Global Methylation Analysis

    Directory of Open Access Journals (Sweden)

    Luca Lambertini

    2017-12-01

    Full Text Available Polycystic ovary syndrome (PCOS affects 5–15% of women. PCOS is a heterogeneous disorder displaying endocrine, metabolic, and reproductive dysfunction and cardiovascular risk manifestations. Evidence of heritability exists, but only a portion of the genetic transmission has been identified by genome-wide association studies and linkage studies, suggesting epigenetic phenomena may play a role. Evidence implicates intrauterine influences in the genesis of PCOS. This was a pilot study that aimed at identifying an epigenetic PCOS reprogramming signature by profiling the methylation of the DNA extracted from umbilical cord blood (UCB from 12 subjects undergoing in vitro fertilization. Six subjects were anovulatory PCOS women diagnosed by Rotterdam criteria and six ovulatory non-PCOS women matched for age and body mass index. UCB was collected at delivery of the placenta; the DNA was extracted and submitted to methylation analysis. A differential methylation picture of prevalent hypomethylation affecting 918 genes was detected. Of these, 595 genes (64.8% carried single or multiple hypomethylated CpG dinucleotides and 323 genes (35.2% single or multiple hypermethylated CpG dinucleotides. The Ingenuity Pathway Analysis (IPA online platform enlisted 908 of the 918 input genes and clustered 794 of them into 21 gene networks. Key features of the primary networks scored by IPA included carbohydrate and lipid metabolism, neurotransmitter signaling, cardiovascular system development and function, glycosaminoglycan signaling regulation and control of amino acid biosynthesis. Central to the network activities were genes controlling hormonal regulation (ESR1, mitochondrial activity (APP, PARK2, and glucose metabolism (INS. Regulatory pathways such as G-protein coupled receptor signaling, inositol metabolism, and inflammatory response were also highlighted. These data suggested the existence of a putative “PCOS epigenomic superpathway” with three main

  19. Systemic inflammatory response syndrome in patients with spinal cord injury: does its presence at admission affect patient outcomes? Clinical article.

    Science.gov (United States)

    Kesani, Anil K; Urquhart, Jennifer C; Bedard, Nathan; Leelapattana, Pittavat; Siddiqi, Fawaz; Gurr, Kevin R; Bailey, Christopher S

    2014-08-01

    The object in this study was to determine whether the presence of systemic inflammatory response syndrome (SIRS) in patients with traumatic spinal cord injury (SCI) on admission is related to subsequent clinical outcome in terms of length of stay (LOS), complications, and mortality. The authors retrospectively reviewed the charts of 193 patients with acute traumatic SCI who had been hospitalized at their institution between 2006 and 2012. Patients were excluded from analysis if they had insufficient SIRS data, a cauda equina injury, a previous SCI, a preexisting neurological condition, or a condition on admission that prevented appropriate neurological assessment. Complications were counted only once per patient and were considered minor if they were severe enough to warrant treatment and major if they were life threatening. Demographics, injury characteristics, and outcomes were compared between individuals who had 2 or more SIRS criteria (SIRS+) and those who had 0 or 1 SIRS criterion (SIRS-) at admission. Multivariate logistic regression (enter method) was used to determine the relative contribution of SIRS+ at admission in predicting the outcomes of mortality, LOS in the intensive care unit (ICU), hospital LOS, and at least one major complication during the acute hospitalization. The American Spinal Injury Association Impairment Scale grade and patient age were included as covariates. Ninety-three patients were eligible for analysis. At admission 47.3% of patients had 2 or more SIRS criteria. The SIRS+ patients had higher Injury Severity Scores (24.3 ±10.6 vs. 30.2 ±11.3) and a higher frequency of both at least one major complication during acute hospitalization (26.5% vs. 50.0%) and a fracture-dislocation pattern of injury (26.5% vs. 59.1%) than the SIRS- patients (p admission predicted an ICU LOS > 10 days, hospital LOS > 25 days, and at least one complication during the acute hospitalization. A protocol to identify SCI patients with SIRS at admission may

  20. [A case of anti-AQP4 antibody-positive recurrent myelitis overlapped with autoimmune disorders including incomplete CREST syndrome revealed multiple discontinuous cord lesions].

    Science.gov (United States)

    Takahashi, Makio; Nagata, Rie; Ozaki, Akihiko; Kaneko, Satoshi; Saiki, Hidemoto; Matsumoto, Sadayuki

    2009-01-01

    A 65-year-old woman presenting with multiple autoimmune disorders including incomplete CREST overlapping with aquaporin 4 (AQP4) antibody-positive recurrent myelitis was reported. She also clinically suffered from Sjogren syndrome and primary biliary cirrhosis (PBC). She had dysesthesia below C4 level, mild motor weakness and hyperreflexia without pathological reflexes on bilateral lower extremities. A T2-weighted MRI indicated multiple discontinuous spinal cord lesions at C1-5 and T7/8. A visual evoked potential study disclosed bilateral prolonged latency of P100. She clinically manifested not only incomplete CREST syndrome (facial teleangiectasia, sclerodactyly in bilateral fingers, and Raynaud's phenomenon), but also Sjögren (sicca syndrome) and PBC (jaundice). Immunoserological study showed that she was positive for anti-nuclear, anti-centromere, and anti-AQP4 (= NMO-IgG) antibodies. A combination therapy with corticosteroid and plasmapheresis was effective for all clinical symptoms. Therefore, this case stresses on the relevance of anti-AQP 4 antibody to the other overlapping autoimmune disorders, such as CREST syndrome, when recurrent myelitis is clinically diagnosed.

  1. Electrodynamic tethers for energy conversion

    Science.gov (United States)

    Nobles, W.

    1986-01-01

    Conductive tethers have been proposed as a new method for converting orbital mechanical energy into electrical power for use on-board a satellite (generator mode) or conversely (motor mode) as a method of providing electric propulsion using electrical energy from the satellite. The operating characteristics of such systems are functionally dependent on orbit altitude and inclination. Effects of these relationships are examined to determine acceptable regions of application. To identify system design considerations, a specific set of system performance goals and requirements are selected. The case selected is for a 25 kW auxiliary power system for use on Space Station. Appropriate system design considerations are developed, and the resulting system is described.

  2. Golgi GRASPs: moonlighting membrane tethers

    Directory of Open Access Journals (Sweden)

    Jarvela T

    2012-05-01

    Full Text Available Timothy Jarvela, Adam D LinstedtDepartment of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USAAbstract: The identification of mammalian Golgi reassembly stacking proteins (GRASPs 15 years ago was followed by experiments implicating them in diverse functions, including two differing structural roles in Golgi biogenesis and at least two distinct roles in the secretion of proteins. GRASP55 and GRASP65 are localized to cis and medial/trans Golgi cisternae, respectively. They are both required for stacking of Golgi membranes in a Golgi reassembly assay. Depletion of either GRASP from cultured cells prevents the linking of Golgi membranes into their normal ribbon-like network. While GRASPs are not required for transport of secretory cargo per se, they are required for ER-to-Golgi transport of certain specific cargo, such as those containing a C-terminal valine motif. Surprisingly, GRASPs also promote secretion of cargo by the so-called unconventional secretory pathway, which bypasses the Golgi apparatus where the GRASPs reside. Furthermore, regulation of GRASP activity is now recognized for its connections to cell cycle control, development, and disease. Underlying these diverse activities is the structurally conserved N-terminal GRASP domain whose crystal structure was recently determined. It consists of a tandem array of atypical PSD95–DlgA–Zo–1 (PDZ domains, which are well-known protein–protein interaction motifs. The GRASP PDZ domains are used to localize the proteins to the Golgi as well as GRASP-mediated membrane tethering and cargo interactions. These activities are regulated, in part, by phosphorylation of the large unstructured C-terminal domain.Keywords: GRASP, review, membrane, tether, PDZ domain, secretory chaperone, unconventional secretion

  3. The space station tethered elevator system

    Science.gov (United States)

    Anderson, Loren A.

    1989-01-01

    The optimized conceptual engineering design of a space station tethered elevator is presented. The elevator is an unmanned mobile structure which operates on a ten kilometer tether spanning the distance between the Space Station and a tethered platform. Elevator capabilities include providing access to residual gravity levels, remote servicing, and transportation to any point along a tether. The potential uses, parameters, and evolution of the spacecraft design are discussed. Engineering development of the tethered elevator is the result of work conducted in the following areas: structural configurations; robotics, drive mechanisms; and power generation and transmission systems. The structural configuration of the elevator is presented. The structure supports, houses, and protects all systems on board the elevator. The implementation of robotics on board the elevator is discussed. Elevator robotics allow for the deployment, retrieval, and manipulation of tethered objects. Robotic manipulators also aid in hooking the elevator on a tether. Critical to the operation of the tethered elevator is the design of its drive mechanisms, which are discussed. Two drivers, located internal to the elevator, propel the vehicle along a tether. These modular components consist of endless toothed belts, shunt-wound motors, regenerative power braking, and computer controlled linear actuators. The designs of self-sufficient power generation and transmission systems are reviewed. Thorough research indicates all components of the elevator will operate under power provided by fuel cells. The fuel cell systems will power the vehicle at seven kilowatts continuously and twelve kilowatts maximally. A set of secondary fuel cells provides redundancy in the unlikely event of a primary system failure. Power storage exists in the form of Nickel-Hydrogen batteries capable of powering the elevator under maximum loads.

  4. A risk factor analysis of outcomes after unrelated cord blood transplantation for children with Wiskott-Aldrich syndrome

    NARCIS (Netherlands)

    Shekhovtsova, Zhanna; Bonfim, Carmem M.; Ruggeri, Annalisa; Nichele, Samantha; Page, Kristin M.; Alseraihy, Amal; Barriga, Francisco; de Toledo Codina, José Sánchez; Veys, Paul; Boelens, Jaap Jan; Mellgren, Karin; Bittencourt, Henrique; O’Brien, Tracey; Shaw, Peter J.; Chybicka, Alicja; Volt, Fernanda; Giannotti, Federica; Gluckman, Eliane; Kurtzberg, Joanne; Gennery, Andrew R.; Rocha, Vanderson; Eurocord, Cord Blood Committee of Cellular Therapy and Immunobiology Working Party of the EBMT, Federal University of Parana, Duke University Medical Center and Inborn Errors Working Party of the EBMT

    2017-01-01

    Wiskott-Aldrich syndrome is a severe X-linked recessive immune deficiency disorder. A scoring system of Wiskott-Aldrich syndrome severity (0.5-5) distinguishes two phenotypes: X-linked thrombocytopenia and classic Wiskott-Aldrich syndrome. Hematopoietic cell transplantation is curative for

  5. Tethered satellite thermal design and test

    Science.gov (United States)

    Chapter, John J.

    1991-01-01

    The Tethered Satellite System (TSS) is the first Shuttle Orbiter mission that investigates electrodynamic phenomenon of a 20 km conductive tether, in space. The TSS Mission is planned for January 1992. The 'Deployer' that provides the mechanisms that control a tethered satellite is mounted on a Spacelab Pallet. The Deployer thermal design uses Multilayer Insulation (MLI), heaters, and the Spacelab payload freon loop. The pallet and Deployer are isolated from the space thermal environment with MLI that forms an enclosure that is a unique part of the thermal design. This paper describes the TSS thermal design, presents the analysis approach, and details the Deployer thermal balance test.

  6. Sudden proximal spinal dislocation with complete spinal cord injury 1 week after spinal fusion in a child with Prader-Willi syndrome: a case report.

    Science.gov (United States)

    de Baat, Paul; van Tankeren, Esther; de Lind van Wijngaarden, Roderick F A; de Klerk, Luuk W L

    2011-12-15

    Case report. To describe a sudden spinal cord injury in a girl with Prader-Willi syndrome (PWS) 1 week after posterior T2-L3 fusion. PWS is a genetic disorder characterized by several features including growth deficiency, hypotonia, obesity, and spinal deformities. In PWS patients the prevalence of scoliosis and of kyphosis is reported to be 15% to 86% and 8% to 40%, respectively. Operative treatment carries specific and serious risks in these patients. A 13-year-old girl with PWS underwent a ventral release and a posterior spinal fusion for a scoliosis with hyperkyphosis of the thoracic spine. Preoperatively, she had no osteopenia or obesity. Posterior instrumentation consisted of fixation with pedicle screws, proximally assisted by a bilateral transverse hook to prevent junctional hyperkyphosis. Postoperative recovery was initially uneventful; however, 1 week after operation the patient suddenly suffered a complete spinal cord lesion at level T4. This was due to myelum compression with a spinal dislocation cranial to the fusion level, and subsequent proximal hook failure. The patient underwent immediate removal of the transverse hooks, an extension of the fusion to T1, and a laminectomy at T2. Eighteen months after the event she was still paraplegic. This report describes a sudden and complete spinal cord lesion 1 week after spinal fusion in a child with PWS. Although such an event is often attributed to osteopenia, this was not proven in this case. To our knowledge, this is the first report to describe this event developing so soon and so suddenly after primary surgery. This case report confirms that spinal surgery in patients with PWS carries an increased risk of junctional hyperkyphosis and pullout of hardware.

  7. Dorsal Root Ganglion Stimulation for Complex Regional Pain Syndrome (CRPS) Recurrence after Amputation for CRPS, and Failure of Conventional Spinal Cord Stimulation.

    Science.gov (United States)

    Goebel, Andreas; Lewis, Sarah; Phillip, Rhodri; Sharma, Manohar

    2017-04-18

    Limb amputation is sometimes being performed in long-standing complex regional pain syndrome (CRPS), although little evidence is available guiding management decisions, including how CRPS recurrence should be managed. This report details the management of a young soldier with CRPS recurrence 2 years after midtibial amputation for CRPS. Conventional spinal cord stimulation did not achieve paraesthetic coverage, or pain relief in the stump, whereas L4 dorsal root ganglion stimulation achieved both coverage and initially modest pain relief, and over time, substantial pain relief. Current evidence does not support the use of amputation to improve either pain or function in CRPS. Before a decision is made, in exceptional cases, about referral for amputation, dorsal root ganglion stimulation should be considered as a potentially effective treatment, even where conventional spinal cord stimulator treatment has failed to achieve reliable paraesthetic cover. Furthermore, this treatment may provide pain relief in those patients with CRPS recurrence in the stump after amputation. © 2017 World Institute of Pain.

  8. Immediate Return to Ambulation and Improved Functional Capacity for Rehabilitation in Complex Regional Pain Syndrome following Early Implantation of a Spinal Cord Stimulation System

    Directory of Open Access Journals (Sweden)

    Brandon Jesse Goff

    2014-01-01

    Full Text Available Complex regional pain syndrome (CRPS is a neuropathic pain condition that is characterized by vasomotor, sensory, sudomotor, and motor symptoms. Spinal cord stimulation (SCS has been successfully utilized for the treatment of pain refractory to conventional therapies. We present a case of a previously highly functioning 54-year-old female who developed a rarely reported case of idiopathic CRPS of the right ankle which spontaneously occurred four months after an uncomplicated anterior cervical disc fusion. This condition resulted in severe pain and functional impairment that was unresponsive to pharmacological management. The patient’s rehabilitation was severely stymied by her excruciating pain. However, with the initiation of spinal cord stimulation, her pain was adequately controlled allowing for progression to full unassisted ambulation, advancing functional capacity, and improving quality of life. This case report supports the concept that rapid progression to neuromodulation, rather than delays that occur due to attempts at serial sympathetic blocks, may better control symptoms leading allowing for a more meaningful recovery.

  9. Dynamics analysis of electrodynamic satellite tethers. Equations of motion and numerical solution algorithms for the tether

    Science.gov (United States)

    Nacozy, P. E.

    1984-01-01

    The equations of motion are developed for a perfectly flexible, inelastic tether with a satellite at its extremity. The tether is attached to a space vehicle in orbit. The tether is allowed to possess electrical conductivity. A numerical solution algorithm to provide the motion of the tether and satellite system is presented. The resulting differential equations can be solved by various existing standard numerical integration computer programs. The resulting differential equations allow the introduction of approximations that can lead to analytical, approximate general solutions. The differential equations allow more dynamical insight of the motion.

  10. [Spinal cord stimulation (SCS) as a treatment for the spread phenomenon related to complex regional pain syndrome type- I (CRPS-I )].

    Science.gov (United States)

    Goto, Shinichi; Taira, Takaomi; Hori, Tomokatsu

    2009-09-01

    The authors describe an experience of spinal cord stimulation (SCS) in a 30-year-old woman who developed complex regional pain syndrome type-I (CRPS-I) with spread phenomenon. She had received lumbar SCS under a diagnosis of CRPS-I in her left leg for 8 years. She had refractory pain in her right arm for the recent two years. There was no new lesion explaining her refractory pain on physical or radiological examination. Thus, the pain in her right upper arm was considered as spread phenomenon of CRPS-I. Test stimulation with cervical epidural spinal electrode showed good results and the pulse generator was implanted. It is suggested that the symptom of CRPS-I involving spread phenomenon was possibly due to a cortical reorganization. But a certain effect of SCS may be contributing to the favorable results of test stimulation for the treatment of CRPS-I with spread phenomenon in this case.

  11. Numerical modelling of elastic space tethers

    DEFF Research Database (Denmark)

    Kristiansen, Kristian Uldall; Palmer, P. L.; Roberts, R. M.

    2012-01-01

    In this paper the importance of the ill-posedness of the classical, non-dissipative massive tether model on an orbiting tether system is studied numerically. The computations document that via the regularisation of bending resistance a more reliable numerical integrator can be produced. Furthermore......, the numerical experiments of an orbiting tether system show that bending may introduce significant forces in some regions of phase space. Finally, numerical evidence for the existence of an almost invariant slow manifold of the singularly perturbed, regularised, non-dissipative massive tether model is provided....... It is also shown that on the slow manifold the dynamics of the satellites are well-approximated by the finite dimensional slack-spring model....

  12. Tether as a dynamic transmission line

    Science.gov (United States)

    Gullahorn, Gordon E.; Hohlfeld, Robert G.

    1988-01-01

    The effect of longitudinal impulses on a satellite when a continuum tether from the Shuttle or Space Station is included is investigated. It is demonstrated that, taking the continuum nature of the tether into account, the sharp onset of a forcing impulse at the Shuttle end is perceived on board the satellite. The magnitude of the satellite response is diminished from that of the forcing impulse, and the response exhibits a broadened exponential tailoff. These are due primarily to the coupling between the tether and the satellite and its influence on an impinging impulsive wave, and not on the whole system as in the spring-mass model. The full impulse response function can be quite complex, showing repeated impulses as the tether wave bounces back and forth between the satellite and Shuttle, and having a different shape at each impingement on the satellite.

  13. FCAPD Protective Coating for Space Tethers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Alameda Applied Sciences Corporation (AASC) proposes to demonstrate extended service lifetime of space tethers in the Low Earth Orbit (LEO) environment by using...

  14. Reduced-Intensity Allogeneic Transplant for Acute Myeloid Leukemia and Myelodysplastic Syndrome Using Combined CD34-Selected Haploidentical Graft and a Single Umbilical Cord Unit Compared with Matched Unrelated Donor Stem Cells in Older Adults.

    Science.gov (United States)

    Tsai, Stephanie B; Rhodes, Joanna; Liu, Hongtao; Shore, Tsiporah; Bishop, Michael; Cushing, Melissa M; Gergis, Usama; Godley, Lucy; Kline, Justin; Larson, Richard A; Mayer, Sebastian; Odenike, Olatoyosi; Stock, Wendy; Wickrema, Amittha; van Besien, Koen; Artz, Andrew S

    2017-12-27

    Haplo/cord transplantation combines an umbilical cord blood (UCB) graft with CD34-selected haploidentical cells and results in rapid hematopoietic recovery followed by durable UCB engraftment. We compared outcomes of transplants in older patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndromes (MDS) who received either HLA-matched unrelated donor (MUD) cells or haplo/cord grafts. Between 2007 and 2013, 109 adults ages 50 and older underwent similar reduced-intensity conditioning with fludarabine and melphalan and antibody-mediated T cell depletion for AML (n = 83) or high-risk MDS (n = 26) followed by either a MUD (n = 68) or haplo/cord (n = 41) graft. Patient characteristics were similar for each graft source except for some patients receiving a haplo/cord transplant (P = .01). One half of the AML patients were not in remission. Two-year progression-free survival (PFS), overall survival (OS), and graft-versus-host disease-free relapse-free survival were 38%, 48%, and 32.1% for MUD and 33%, 48%, and 33.8% for haplo/cord transplants (P = .62 for PFS; P = .97 for OS; P= .84), respectively. Acute grades II to IV and chronic graft-versus-host-disease rates did not differ at 19.5% and 4.9% in haplo/cord compared with 25% and 7.4% after MUD (P = .53 and P = .62, respectively). Multivariate analysis confirmed no significant differences in transplant outcomes by donor type. Haplo/cord reduced-intensity transplantation achieves similar outcomes relative to MUD in older AML and MDS patients, making this a promising option for those without matched donors. Copyright © 2018. Published by Elsevier Inc.

  15. A Case Report of a Patient with Leukocyte Adhesion Deficiency Type I Syndrome and Normal Time of Umbilical Cord Detachment

    Directory of Open Access Journals (Sweden)

    M. Safari

    2016-04-01

    Full Text Available Introduction: Leukocyte adhesion deficiency type 1 is a rare disorder of function of neutrophils which presents with recurrent bacterial and fungal infections. The patients usually have a history of delayed umbilical cord detachment. Case Report: The patient was a fourteen-month-old boy with recurrent bronchopneumonia, skin abscess and oral candidiasis. There was a history of abscess formation in site of vaccine injection in two and four months of age. The umbilical cord detachment was occurred in the 6th day of birth. Laboratory studies showed marked leukocytosis and neutrophilia .Flowcytometry showed low amount of CD18. These were all compatible with a diagnosis of leukocyte adhesion deficiency type I (LADs1. Conclusions: The patients die in the event of a delay in diagnosis because of recurrent severe infections. Early diagnosis and treatment of these diseases by stem cell transplantation improve the survival of the patient. (Sci J Hamadan Univ Med Sci 2016; 23 (1:88-92

  16. Development of the flight tether for ProSEDS

    Science.gov (United States)

    Curtis, Leslie; Vaughn, Jason; Welzyn, Ken; Carroll, Joe

    2002-01-01

    The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system to generate thrust in space by decreasing the orbital altitude of a Delta II Expendable Launch Vehicle second stage. ProSEDS will use the flight-proven Small Expendable Deployer System to deploy a newly designed and developed tether which will provide tether generated drag thrust of ~0.4 N. The development and production of very long tethers with specific properties for performance and survivability will be required to enable future tether missions. The ProSEDS tether design and the development process may provide some lessons learned for these future missions. The ProSEDS system requirements drove the design of the tether to have three different sections of tether each serving a specialized purpose. The tether is a total of 15 kilometers long: 10 kilometers of a non-conductive Dyneema lead tether; 5 km of CCOR conductive coated wire; and 220 meters of insulated wire with a protective Kevlar overbraid. Production and joining of long tether lengths involved many development efforts. Extensive testing of tether materials including ground deployment of the full-length ProSEDS tether was conducted to validate the tether design and performance before flight. .

  17. Cord Blood

    Directory of Open Access Journals (Sweden)

    Saeed Abroun

    2014-05-01

    Full Text Available   Stem cells are naïve or master cells. This means they can transform into special 200 cell types as needed by body, and each of these cells has just one function. Stem cells are found in many parts of the human body, although some sources have richer concentrations than others. Some excellent sources of stem cells, such as bone marrow, peripheral blood, cord blood, other tissue stem cells and human embryos, which last one are controversial and their use can be illegal in some countries. Cord blood is a sample of blood taken from a newborn baby's umbilical cord. It is a rich source of stem cells, umbilical cord blood and tissue are collected from material that normally has no use following a child’s birth. Umbilical cord blood and tissue cells are rich sources of stem cells, which have been used in the treatment of over 80 diseases including leukemia, lymphoma and anemia as bone marrow stem cell potency.  The most common disease category has been leukemia. The next largest group is inherited diseases. Patients with lymphoma, myelodysplasia and severe aplastic anemia have also been successfully transplanted with cord blood. Cord blood is obtained by syringing out the placenta through the umbilical cord at the time of childbirth, after the cord has been detached from the newborn. Collecting stem cells from umbilical blood and tissue is ethical, pain-free, safe and simple. When they are needed to treat your child later in life, there will be no rejection or incompatibility issues, as the procedure will be using their own cells. In contrast, stem cells from donors do have these potential problems. By consider about cord blood potency, cord blood banks (familial or public were established. In IRAN, four cord blood banks has activity, Shariati BMT center cord blood bank, Royan familial cord blood banks, Royan public cord blood banks and Iranian Blood Transfusion Organ cord blood banks. Despite 50,000 sample which storage in these banks, but the

  18. Laser-induced tether & spouts

    Science.gov (United States)

    Delville, Jean-Pierre

    2004-03-01

    Since the seminal work of Ashkin and Dziedzic on the deformation of transparent free-surfaces induced by laser waves, the optical radiation pressure has been recognized as very appealing to locally manipulate liquid interfaces. While the first developments essentially exploited the interface bending for optical applications in adaptive lensing, radiation pressure effects have recently received renewed interest in connection with nano/bio-technologies, as a non-intrusive tool to probe microscopic surface properties of soft materials including cell stretching, or membrane and interface visco-elasticity. However, as the optical bending of a fluid interface is generally weak, these experiments were essentially limited to the linear regime in deformation. Non-linear behaviors can nevertheless be investigated using very soft transparent liquid interfaces to enhance light effects. At large optical excitation, either a large stable tether is formed, or else a break-up of the interface occurs, depending on the direction of the beam propagation. Physically, the reason for this asymmetry can be traced to whether total reflection of light at deformed interface occurs or not. Laser-induced interface instability leads to the formation of a stationary beam-centered liquid micro-jet emitting droplets, which anticipates the bases for new applications in micro-fluidics and liquid micro-spraying. On the other hand, the method can be extended to form microscopic liquid bridges of very large aspect ratio, because optical forces are able to overcome the fundamental Rayleigh-Plateau limitation. As laser-induced micro-jets, laser-sustained liquid columns are tunable in aspect ratio and adjustable in direction. Consequently, the applications range of "opto-hydrodynamic" interface instability is wide, going from micro-optics (i.e. liquid columns also behave as soft optical fibers) to micro-fluidics, as fluid transfer can be optically monitored and directed in three dimensions.

  19. Spinal Cord Disorders.

    Science.gov (United States)

    Tettenborn, Barbara; Hägele-Link, Stefan

    2015-01-01

    The spinal cord is the main pathway for information, connecting the brain and the peripheral nervous system. Any disorder that results in spinal cord dysfunction will have a dramatic impact on the patient's quality of life. This review focusses on myelopathy, specifically, on the acute and subacute clinical presentations and the inflammatory and vascular etiology of this widespread disorder. Myelopathy following spinal cord injury is a generic term referring to a lesion that affects the spinal cord following traumatic injury, or autoimmune, infectious, neoplastic, vascular and hereditary degenerative diseases. Depending on the patient's medical history, the underlying clinical syndrome and the temporal course of the manifestation, the clinician must account for a wide range of possible differential diagnoses. Spinal cord disorders pose a tremendous challenge for the clinician, as they show great variability in clinical presentation but can have potentially devastating sequelae. The acute and sometimes urgent nature of therapeutic management is highly dependent on the underlying disorder, often necessitating a combination of approaches including surgical or conservative therapies (including immunomodulatory therapy) and an interdisciplinary approach to achieve the best outcomes. © 2015 S. Karger AG, Basel.

  20. First Case of Autonomic Dysreflexia Following Elective Lower Thoracic Spinal Cord Transection in a Spina Bifida Adult.

    Science.gov (United States)

    Garces, Juanita; Mathkour, Mansour; Scullen, Tyler; Kahn, Lora; Biro, Erin; Pham, Alex; Sulaiman, Olawale A R; Smith, Roger; Bui, Cuong J

    2017-12-01

    Spinal cord transection is a radical but effective treatment for highly selective cases of symptomatic spinal retethering in paraplegic spina bifida patients. Autonomic dysreflexia (AD) is a potentially life-threatening syndrome involving a dysregulated sympathetic discharge reflex commonly seen following cervical and high thoracic spinal cord injury, leading to a disconnect between autonomic pathways above and below the lesion that can lead to severe complications including uncontrolled hypertension, bradycardia, stroke, and potentially death. Herein we present a case in which a paraplegic spina bifida patient presenting with symptomatic spinal retethering experienced autonomic dysreflexia following an elective spinal cord transection. A 51-year-old male with a history of complex spina bifida presented with an active cerebrospinal fluid leak. Physical examination revealed a thin covering of abnormal epidermis over the large placode. Magnetic resonance imaging revealed a large myelomeningocele defect with posterior element defects spanning from L2 to the sacrum with evidence of tethering. The patient underwent an intradural transection of the spinal cord with a "blind-pouch" closure of the dura at the level of T12/L1. Postoperatively, the patient developed intermittent episodes of hypertension, bradycardia, headaches, altered mental status, severe perspiration, and red flushing of the upper torso, face, and arms. The diagnosis of AD was made clinically and managed with a positive response to a combination of beta- and alpha-blockade along with patient education on avoidance of common AD triggers. At 5-year follow-up the patient has continued to do well on medication. This case highlights a potential major side effect from elective transection of the spinal cord. If unrecognized and untreated, AD can cause significant distress and morbidity. We hope this first case report serves to supplement existing data and aid in future surgical and medical decision

  1. Metastatic ovarian sex-cord stromal tumor with annular tubules in a patient without Peutz-Jeghers syndrome.

    Science.gov (United States)

    Dart, Kimi; Schwartzenfeld, Ted; Brandes, Warren; D'Errico, Anthony; Stender, Michael

    2014-06-01

    Sex-cord stromal tumors (SCSTs) with annular tubules (SCTATs) are a small class of ovarian lesions that possess histologic features of both Sertoli and granulosa cells. Approximately one-third of patients with SCTAT also have Peutz-Jaghers syndreome, which makes these cases especially rare. Patients with non-PJS-associated SCTAT make up the remaining two-thirds; 20% of these cases have a metastatic presentation. Metastasis of these tumors to the head and neck region has only been reported in a few instances. In this article we report a case of a 25-year-old woman who presented with "a lump in her throat" and was ultimately diagnosed with SCTAT. We also discuss the current protocols in the diagnosis and treatment of this entity.

  2. Tethers in Space : A propellantless propulsion in-orbit demonstration

    NARCIS (Netherlands)

    Kruijff, M.

    2011-01-01

    Space tethers are cables that connect satellites or other endmasses in orbit. The emptiness of space and the near-weightlessness there make it possible to deploy very long and thin tethers. By exploiting basic principles of physics, tethers can provide propellantless propulsion and enable unique

  3. Dynamics and offset control of tethered space-tug system

    Science.gov (United States)

    Zhang, Jingrui; Yang, Keying; Qi, Rui

    2018-01-01

    Tethered space-tug system is regarded as one of the most promising active debris removal technologies to effectively decrease the steep increasing population of space debris. In order to suppress the spin of space debris, single-tethered space-tug system is employed by regulating the tether. Unfortunately, this system is underactuated as tether length is the only input, and there are two control objectives: the spinning debris and the vibration of tether. Thus, it may suffer great oscillations and result in failure in space debris removal. This paper presents the study of attitude stabilization of the single-tethered space-tug system using not only tether length but also the offset of tether attachment point to suppress the spin of debris, so as to accomplish the space debris removal mission. Firstly, a precise 3D mathematical model in which the debris and tug are both treated as rigid bodies is developed to study the dynamical evolution of the tethered space-tug system. The relative motion equation of the system is described using Lagrange method. Secondly, the dynamic characteristic of the system is analyzed and an offset control law is designed to stabilize the spin of debris by exploiting the variation of tether offset and the regulation of tether length. Besides, an estimation formula is proposed to evaluate the capability of tether for suppressing spinning debris. Finally, the effectiveness of attitude stabilization by the utilization of the proposed scheme is demonstrated via numerical case studies.

  4. Retained medullary cord extending to a sacral subcutaneous meningocele.

    Science.gov (United States)

    Murakami, Nobuya; Morioka, Takato; Shimogawa, Takafumi; Hashiguchi, Kimiaki; Mukae, Nobutaka; Uchihashi, Kazuyoshi; Suzuki, Satoshi O; Iihara, Koji

    2017-11-03

    A retained medullary cord (RMC) is a rare closed spinal dysraphism with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac. One case extending down to the base of a subcutaneous meningocele at the sacral level has been reported. We report on three cases of closed spinal dysraphism, in which a spinal cord-like tethering structure extended out from the dural cul-de-sac and terminated at a skin-covered meningocele sac in the sacrococcygeal region, which was well delineated in curvilinear coronal reconstructed images of 3D-heavily T2-weighted images (3D-hT2WI). Intraoperative neurophysiology revealed the spinal cord-like tethering structure was nonfunctional, and histopathology showed that it consisted of central nervous system tissue, consistent with RMC. The tethering structure histologically contained a glioneuronal core with an ependymal-like lumen and smooth muscle, which may indicate developmental failure during secondary neurulation. When the RMC extending to a meningocele is demonstrated with the detailed magnet resonance imaging including 3D-hT2WI, decision to cut the cord-like structure for untethering of the nervous tissue should be made under careful intraoperative neurophysiological monitoring.

  5. MID1 and MID2 homo- and heterodimerise to tether the rapamycin-sensitive PP2A regulatory subunit, Alpha 4, to microtubules: implications for the clinical variability of X-linked Opitz GBBB syndrome and other developmental disorders

    Directory of Open Access Journals (Sweden)

    Cox Timothy C

    2002-01-01

    Full Text Available Abstract Background Patients with Opitz GBBB syndrome present with a variable array of developmental defects including craniofacial, cardiac, and genital anomalies. Mutations in the X-linked MID1 gene, which encodes a microtubule-binding protein, have been found in ~50% of Opitz GBBB syndrome patients consistent with the genetically heterogeneous nature of the disorder. A protein highly related to MID1, called MID2, has also been described that similarly associates with microtubules. Results To identify protein partners of MID1 and MID2 we undertook two separate yeast two-hybrid screens. Using this system we identified Alpha 4, a regulatory subunit of PP2-type phosphatases and a key component of the rapamycin-sensitive signaling pathway, as a strong interactor of both proteins. Analysis of domain-specific deletions has shown that the B-boxes of both MID1 and MID2 mediate the interaction with Alpha 4, the first demonstration in an RBCC protein of a specific role for the B-box region. In addition, we show that the MID1/2 coiled-coil motifs mediate both homo- and hetero-dimerisation, and that dimerisation is a prerequisite for association of the MID-Alpha 4 complex with microtubules. Conclusions Our findings not only implicate Alpha 4 in the pathogenesis of Opitz GBBB syndrome but also support our earlier hypothesis that MID2 is a modifier of the X-linked phenotype. Of further note is the observation that Alpha 4 maps to Xq13 within the region showing linkage to FG (Opitz-Kaveggia syndrome. Overlap in the clinical features of FG and Opitz GBBB syndromes warrants investigation of Alpha 4 as a candidate for causing FG syndrome.

  6. Dravet Syndrome

    Science.gov (United States)

    ... NINDS Focus on Research Alzheimer's & Related Dementias Bioengineering Epilepsy Health Disparities Neural Interfaces Parkinson's Disease Spinal Cord ... basic and clinical research on all types of epilepsy, including Dravet syndrome. Study of the genetic defects ...

  7. Tethered spacecraft in asteroid gravitational environment

    Science.gov (United States)

    Burov, Alexander A.; Guerman, Anna D.; Kosenko, Ivan I.; Nikonov, Vasily I.

    2018-02-01

    Relative equilibria of a pendulum attached to the surface of a uniformly rotating celestial body are considered. The locations of the tether anchor that correspond to a given spacecraft position are defined. The domains, where the spacecraft can be held with the help of such a pendulum, are also described. Stability of the found relative equilibria is studied.

  8. Ionic-Liquid-Tethered Nanoparticles: Hybrid Electrolytes

    KAUST Repository

    Moganty, Surya S.

    2010-10-22

    A new class of solventless electrolytes was created by tethering ionic liquids to hard inorganic ZrO2 nanostructures (see picture; NIM=nanoscale ionic material). These hybrid fluids exhibit exceptional redox stability windows, excellent thermal stability, good lithium transference numbers, long-term interfacial stability in the presence of a lithium anode and, when doped with lithium salt, reasonable ionic conductivities.

  9. Tethered "kiteplane" design for the Laddermill project

    NARCIS (Netherlands)

    Breukels, J.; Ockels, W.

    2005-01-01

    The Laddermill is an innovative concept for generating energy from wind using large kite-like wings on a tether. The wings are able to fly in both the regime of airplanes and kites. We therefore call these structures "kiteplanes". By providing a recurring motion with a large lift during ascending

  10. Nanomechanics of HaloTag tethers.

    Science.gov (United States)

    Popa, Ionel; Berkovich, Ronen; Alegre-Cebollada, Jorge; Badilla, Carmen L; Rivas-Pardo, Jaime Andrés; Taniguchi, Yukinori; Kawakami, Masaru; Fernandez, Julio M

    2013-08-28

    The active site of the Haloalkane Dehydrogenase (HaloTag) enzyme can be covalently attached to a chloroalkane ligand providing a mechanically strong tether, resistant to large pulling forces. Here we demonstrate the covalent tethering of protein L and I27 polyproteins between an atomic force microscopy (AFM) cantilever and a glass surface using HaloTag anchoring at one end and thiol chemistry at the other end. Covalent tethering is unambiguously confirmed by the observation of full length polyprotein unfolding, combined with high detachment forces that range up to ∼2000 pN. We use these covalently anchored polyproteins to study the remarkable mechanical properties of HaloTag proteins. We show that the force that triggers unfolding of the HaloTag protein exhibits a 4-fold increase, from 131 to 491 pN, when the direction of the applied force is changed from the C-terminus to the N-terminus. Force-clamp experiments reveal that unfolding of the HaloTag protein is twice as sensitive to pulling force compared to protein L and refolds at a slower rate. We show how these properties allow for the long-term observation of protein folding-unfolding cycles at high forces, without interference from the HaloTag tether.

  11. Yielding elastic tethers stabilize robust cell adhesion.

    Directory of Open Access Journals (Sweden)

    Matt J Whitfield

    2014-12-01

    Full Text Available Many bacteria and eukaryotic cells express adhesive proteins at the end of tethers that elongate reversibly at constant or near constant force, which we refer to as yielding elasticity. Here we address the function of yielding elastic adhesive tethers with Escherichia coli bacteria as a model for cell adhesion, using a combination of experiments and simulations. The adhesive bond kinetics and tether elasticity was modeled in the simulations with realistic biophysical models that were fit to new and previously published single molecule force spectroscopy data. The simulations were validated by comparison to experiments measuring the adhesive behavior of E. coli in flowing fluid. Analysis of the simulations demonstrated that yielding elasticity is required for the bacteria to remain bound in high and variable flow conditions, because it allows the force to be distributed evenly between multiple bonds. In contrast, strain-hardening and linear elastic tethers concentrate force on the most vulnerable bonds, which leads to failure of the entire adhesive contact. Load distribution is especially important to noncovalent receptor-ligand bonds, because they become exponentially shorter lived at higher force above a critical force, even if they form catch bonds. The advantage of yielding is likely to extend to any blood cells or pathogens adhering in flow, or to any situation where bonds are stretched unequally due to surface roughness, unequal native bond lengths, or conditions that act to unzip the bonds.

  12. Yielding Elastic Tethers Stabilize Robust Cell Adhesion

    Science.gov (United States)

    Whitfield, Matt J.; Luo, Jonathon P.; Thomas, Wendy E.

    2014-01-01

    Many bacteria and eukaryotic cells express adhesive proteins at the end of tethers that elongate reversibly at constant or near constant force, which we refer to as yielding elasticity. Here we address the function of yielding elastic adhesive tethers with Escherichia coli bacteria as a model for cell adhesion, using a combination of experiments and simulations. The adhesive bond kinetics and tether elasticity was modeled in the simulations with realistic biophysical models that were fit to new and previously published single molecule force spectroscopy data. The simulations were validated by comparison to experiments measuring the adhesive behavior of E. coli in flowing fluid. Analysis of the simulations demonstrated that yielding elasticity is required for the bacteria to remain bound in high and variable flow conditions, because it allows the force to be distributed evenly between multiple bonds. In contrast, strain-hardening and linear elastic tethers concentrate force on the most vulnerable bonds, which leads to failure of the entire adhesive contact. Load distribution is especially important to noncovalent receptor-ligand bonds, because they become exponentially shorter lived at higher force above a critical force, even if they form catch bonds. The advantage of yielding is likely to extend to any blood cells or pathogens adhering in flow, or to any situation where bonds are stretched unequally due to surface roughness, unequal native bond lengths, or conditions that act to unzip the bonds. PMID:25473833

  13. Tethered Aerostat Effects on Nearby Seismometers

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    This report assesses seismic interference generated by a tethered aerostat. The study was motivated by a planned aerostat deployment within the footprint of the Dry Alluvium Geology seismic network. No evidence was found for seismic interference generated by the aerostat, and thus the e ects on the Dry Alluvium Geology sensors will be negligible.

  14. Toward a Broader View of Ube3a in a Mouse Model of Angelman Syndrome: Expression in Brain, Spinal Cord, Sciatic Nerve and Glial Cells.

    Directory of Open Access Journals (Sweden)

    Mark D Grier

    Full Text Available Angelman Syndrome (AS is a devastating neurodevelopmental disorder characterized by developmental delay, speech impairment, movement disorder, sleep disorders and refractory epilepsy. AS is caused by loss of the Ube3a protein encoded for by the imprinted Ube3a gene. Ube3a is expressed nearly exclusively from the maternal chromosome in mature neurons. While imprinting in neurons of the brain has been well described, the imprinting and expression of Ube3a in other neural tissues remains relatively unexplored. Moreover, given the overwhelming deficits in brain function in AS patients, the possibility of disrupted Ube3a expression in the infratentorial nervous system and its consequent disability have been largely ignored. We evaluated the imprinting status of Ube3a in the spinal cord and sciatic nerve and show that it is also imprinted in these neural tissues. Furthermore, a growing body of clinical and radiological evidence has suggested that myelin dysfunction may contribute to morbidity in many neurodevelopmental syndromes. However, findings regarding Ube3a expression in non-neuronal cells of the brain have varied. Utilizing enriched primary cultures of oligodendrocytes and astrocytes, we show that Ube3a is expressed, but not imprinted in these cell types. Unlike many other neurodevelopmental disorders, AS symptoms do not become apparent until roughly 6 to 12 months of age. To determine the temporal expression pattern and silencing, we analyzed Ube3a expression in AS mice at several time points. We confirm relaxed imprinting of Ube3a in neurons of the postnatal developing cortex, but not in structures in which neurogenesis and migration are more complete. This furthers the hypothesis that the apparently normal window of development in AS patients is supported by an incompletely silenced paternal allele in developing neurons, resulting in a relative preservation of Ube3a expression during this crucial epoch of early development.

  15. A prospective study evaluating sleep quality in Failed Back Surgery Syndrome patients treated by multicolumn spinal cord stimulation: study design protocol and presentation of the study population.

    Science.gov (United States)

    Monlezun, O; Lode-Kolz, K; Roulaud, M; Paquereau, J; Ingrand, P; Veyrieras, C; Brandet, C; Guetarni, F; Prévost, A; Bataille, B; Rigoard, P

    2015-03-01

    One of the main consequences of chronic pain syndrome is major impairment of the quality of sleep. Chronic pain and insomnia are independently linked to significant reductions in quality of life and psychiatric morbidity. Recent studies have suggested the efficacy of spinal cord stimulation (SCS) for the treatment of the back pain component in failed back surgery syndrome (FBSS) patients using a multicolumn lead. The main aim of this pilot study is to assess the influence and potential benefits of SCS on sleep quality in refractory FBSS patients implanted with multicolumn SCS and enrolled in the French multicentre ESTIMET study. This is a single-centre, comparative, exploratory, pilot study. Sixteen FBSS patients enrolled in the ESTIMET study and implanted with multicolumn SCS will be monitored for 6months after implantation. Sleep parameters will be recorded by polysomnography, Psychomotor Vigilance Test and Osler tests, actigraphy, sleepiness scales, and sleep quality testing. Sleep will be evaluated before (at the inclusion visit) and after SCS implantation (at the 6-month visit). Secondary objectives will also assess the impact of SCS lead programming (mono vs. multicolumn SCS) and the influence of position-adaptive stimulation at night on sleep quality. The first patient of this ancillary study was enrolled on 21 May, 2012 and recruitment has now been achieved. Primary endpoint findings are expected to be available in 2015. By providing an analysis of the quality of sleep in chronic pain patients who are candidates for implanted neurostimulation, this new approach focuses on an important aspect of quality of life often overlooked in these poly-medication patients. It could show a real clinical benefit and underestimation of these analgesic innovative expensive techniques, where medico-economic analysis, would or would not promote access. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  16. Epidermoid cyst inside anterior sacral meningocele in an adult patient of Currarino syndrome manifesting with meningitis.

    Science.gov (United States)

    Kansal, Ritesh; Mahore, Amit; Dange, Nitin; Kukreja, Sanjay

    2012-01-01

    The Currarino triad, also known as the "Currarino Syndrome", is a rare complex of congenital caudal anomalies including three main features; a sacral bony deformity, anorectal malformations, and a presacral mass. We present an extremely uncommon case of Currarino syndrome in adulthood presenting with repeated episodes of meningitis. Magnetic resonance imaging of spine was suggestive of caudal regression. Cord was low lying, conus ending at L3 level with evidence of tethering at that level. A large cyst was noted in the sacral canal extending forwards in the pelvis through the widened sacral foramina on right side. She was operated through a posterior approach, via sacral laminectomy. Dura was opened in the midline, large silvery white epidermoid tumor was found completely occupying the anterior sacral meningocele. The case and relevant literature is discussed.

  17. Coordinated coupling control of tethered space robot using releasing characteristics of space tether

    Science.gov (United States)

    Huang, Panfeng; Zhang, Fan; Xu, Xiudong; Meng, Zhongjie; Liu, Zhengxiong; Hu, Yongxin

    2016-04-01

    Tethered space robot (TSR) is a new concept of space robot, which is released from the platform satellite, and retrieved via connected tether after space debris capture. In this paper, we propose a new coordinate control scheme for optimal trajectory and attitude tracking, and use releasing motor torque to instead the tension force, since it is difficult to track in practical. Firstly, the 6-DOF dynamics model of TSR is derived, in which the dynamics of tether releasing system is taken into account. Then, we propose and design the coordinated coupled controller, which is composed of a 6-DOF sliding mode controller and a PD controller tether's releasing. Thrust is treated as control input of the 6-DOF sliding mode controller to control the in-plane and out-of-plane angle of the tether and attitude angles of the TSR. The torque of releasing motor is used as input of PD controller, which controls the length rate of space tether. After the verification of the control scheme, finally, the simulation experiment is presented in order to validate the effectiveness of this control method. The results show that TSR can track the optimal approaching trajectory accurately. Simultaneously, the attitude angles can be changed to the desired attitude angles in control period, and the terminal accuracy is ±0.3°.

  18. Theory and Modeling in Support of Tether

    Science.gov (United States)

    Chang, C. L.; Bergeron, G.; Drobot, A. D.; Papadopoulos, K.; Riyopoulos, S.; Szuszczewicz, E.

    1999-01-01

    This final report summarizes the work performed by SAIC's Applied Physics Operation on the modeling and support of Tethered Satellite System missions (TSS-1 and TSS-1R). The SAIC team, known to be Theory and Modeling in Support of Tether (TMST) investigation, was one of the original twelve teams selected in July, 1985 for the first TSS mission. The accomplishments described in this report cover the period December 19, 1985 to September 31, 1999 and are the result of a continuous effort aimed at supporting the TSS missions in the following major areas. During the contract period, the SAIC's TMST investigation acted to: Participate in the planning and the execution on both of the TSS missions; Provide scientific understanding on the issues involved in the electrodynamic tether system operation prior to the TSS missions; Predict ionospheric conditions encountered during the re-flight mission (TSS-lR) based on realtime global ionosounde data; Perform post mission analyses to enhance our understanding on the TSS results. Specifically, we have 1) constructed and improved current collection models and enhanced our understanding on the current-voltage data; 2) investigated the effects of neutral gas in the current collection processes; 3) conducted laboratory experiments to study the discharge phenomena during and after tether-break; and 4) perform numerical simulations to understand data collected by plasma instruments SPES onboard the TSS satellite; Design and produce multi-media CD that highlights TSS mission achievements and convey the knowledge of the tether technology to the general public. Along with discussions of this work, a list of publications and presentations derived from the TMST investigation spanning the reporting period is compiled.

  19. Optimal control of electrodynamic tether satellites

    Science.gov (United States)

    Stevens, Robert E.

    Low thrust propulsion systems offer a fuel-efficient means to maneuver satellites to new orbits, however they can only perform such maneuvers when they are continuously operated for a long time. Such long-term maneuvers occur over many orbital revolutions often rendering short time scale trajectory optimization methods ineffective. An approach to multirevolution, long time scale optimal control of an electrodynamic tether is investigated for a tethered satellite system in Low Earth Orbit with atmospheric drag. Control is assumed to be periodic over several orbits since under the assumptions of a nearly circular orbit, periodic control yields the only solution that significantly contributes to secular changes in the orbital parameters. The optimal control problem is constructed in such a way as to maneuver the satellite to a new orbit while minimizing a cost function subject to the constraints of the time-averaged equations of motion by controlling current in the tether. To accurately capture the tether orbital dynamics, libration is modeled and controlled over long time scales in a similar manner to the orbital states. Libration is addressed in two parts; equilibrium and stability analysis, and control. Libration equations of motion are derived and analyzed to provide equilibrium and stability criteria that define the constraints of the design. A new libration mean square state is introduced and constrained to maintain libration within an acceptable envelope throughout a given maneuver. Optimal control solutions are achieved using a pseudospectral method that maneuver an electrodynamic tether to new orbits over long time scales while managing librational motion using only current in a wire.

  20. Vocal cord paralysis.

    Science.gov (United States)

    Grundfast, K M; Harley, E

    1989-06-01

    The information presented in this article demonstrates that unilateral or bilateral vocal cord paresis or paralysis in infants and children is difficult to diagnose and difficult to manage. In an attempt to provide the otolaryngologist with a concise set of relevant guidelines, the following rules for management are presented here. 1. Suspect bilateral abductor vocal cord paralysis (BAVP) when a neonate or infant presents with high-pitched inspiratory stridor and evidence of airway compromise. Factors that should increase the suspicion of BAVP include associated Arnold-Chiari malformation; congenital anatomic abnormality involving the mediastinum (for example, tracheoesophageal fistula, vascular ring, other vascular anomalies); dysmorphic syndromes, especially those involving brainstem dysfunction; and manifest findings indicative of neuromuscular disorder. The neonate or infant with Arnold-Chiari malformation and inspiratory stridor has bilateral abductor vocal cord paralysis until proven otherwise. 2. Suspect unilateral vocal cord paresis or paralysis in an infant or child with hoarse voice, low-pitched cry, or breathy cry or voice. The infant who develops mild stridor and hoarse cry following surgical repair of a patent ductus arteriosus or tracheoesophageal fistula has a unilateral vocal cord paralysis until proven otherwise. 3. Direct laryngoscopy with the flexible fiberoptic nasopharyngolaryngoscope and photodocumentation using a videocassette recorder offers the best method for diagnosis of vocal cord paresis or paralysis. Additional diagnostic studies that may be helpful include radiographic studies, CT scan, MRI scan, electromyography of the larynx, and, in older children, stroboscopy. 4. In using a flexible direct laryngoscope be careful not to interpret all motions of the vocal cords or arytenoids as evidence to preclude the diagnosis of vocal cord paralysis or paresis and be careful not to mistake the anterior intraluminal portion of a normal cricoid

  1. Spinal Cauda Equina Stimulation for Alternative Location of Spinal Cord Stimulation in Intractable Phantom Limb Pain Syndrome: A Case Report.

    Science.gov (United States)

    Lee, Pil Moo; So, Yun; Park, Jung Min; Park, Chul Min; Kim, Hae Kyoung; Kim, Jae Hun

    2016-04-01

    Phantom limb pain is a phenomenon in which patients experience pain in a part of the body that no longer exists. In several treatment modalities, spinal cord stimulation (SCS) has been introduced for the management of intractable post-amputation pain. A 46-year-old male patient complained of severe ankle and foot pain, following above-the-knee amputation surgery on the right side amputation surgery three years earlier. Despite undergoing treatment with multiple modalities for pain management involving numerous oral and intravenous medications, nerve blocks, and pulsed radiofrequency (RF) treatment, the effect duration was temporary and the decreases in the patient's pain score were not acceptable. Even the use of SCS did not provide completely satisfactory pain management. However, the trial lead positioning in the cauda equina was able to stimulate the site of the severe pain, and the patient's pain score was dramatically decreased. We report a case of successful pain management with spinal cauda equina stimulation following the failure of SCS in the treatment of intractable phantom limb pain.

  2. Spinal Cauda Equina Stimulation for Alternative Location of Spinal Cord Stimulation in Intractable Phantom Limb Pain Syndrome: A Case Report

    Science.gov (United States)

    Lee, Pil Moo; So, Yun; Park, Jung Min; Park, Chul Min; Kim, Hae Kyoung

    2016-01-01

    Phantom limb pain is a phenomenon in which patients experience pain in a part of the body that no longer exists. In several treatment modalities, spinal cord stimulation (SCS) has been introduced for the management of intractable post-amputation pain. A 46-year-old male patient complained of severe ankle and foot pain, following above-the-knee amputation surgery on the right side amputation surgery three years earlier. Despite undergoing treatment with multiple modalities for pain management involving numerous oral and intravenous medications, nerve blocks, and pulsed radiofrequency (RF) treatment, the effect duration was temporary and the decreases in the patient's pain score were not acceptable. Even the use of SCS did not provide completely satisfactory pain management. However, the trial lead positioning in the cauda equina was able to stimulate the site of the severe pain, and the patient's pain score was dramatically decreased. We report a case of successful pain management with spinal cauda equina stimulation following the failure of SCS in the treatment of intractable phantom limb pain. PMID:27103968

  3. Spinal Cord Vascular Disease

    Directory of Open Access Journals (Sweden)

    Abdoreza Ghoreishi

    2017-02-01

    Full Text Available The spinal cord is subject to many of the same vascular diseases that involve the brain, but its anatomy and embryology render it susceptible to some syndromes that do not have intracranial counterparts.The embryonic arterial supply to the spinal cord derives from intradural vessels that enter at each spinal level and divide to follow the dorsal and ventral roots. SPINAL CORD ISCHEMIA: The midthoracic levels of the spinal cord are traditionally considered to be the most vulnerable to compromise from hypoperfusion, but more recent evidence suggests that the lower thoracic cord is at greater risk . The actual prevalence of spinal cord infarction is unknown, but is generally cited as representing 1% to 2% of all central neurovascular events and 5% to 8% of all acute myelopathies. Weakness (100%, sensory loss (89%, back pain at onset (82%, and urinary complaints requiring catheterization (75% were the most common symptoms of cord ischemia at the time of presentation . Weakness most commonly affects both legs. Examination typically reveals flaccid paresis accompanied by diminished superficial and tendon reflexes below the level of the lesion. Preservation of strength and reflexes suggests the rare syndrome of posterior spinal artery territory infarction. Weakness most commonly affects both legs. Examination typically reveals flaccid paresis accompanied by diminished superficial and tendon reflexes below the level of the lesion. Preservation of strength and reflexes suggests the rare syndrome of posterior spinal artery territory infarction.   Aortic pathologies with regional hemodynamic compromise are the most common cause of spinal cord infarction, accounting for 30% to 40% of cases.                                                                                 The medical management of spinal cord ischemia is generally supportive and focused on reducing risk for

  4. Spinal Cord Injury 101

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    Full Text Available ... and What They Mean Animated Spinal Cord Injury Chart Spinal Cord Injury Facts and Figures Care and ... and What They Mean Animated Spinal Cord Injury Chart Spinal Cord Injury Facts and Figures Care and ...

  5. Spinal Cord Injury 101

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    Full Text Available ... Spinal Cord Injury Facts and Figures Care and Treatment After SCI Spinal Cord Injury Rehabilitation Pediatric Spinal ... Spinal Cord Injury Facts and Figures Care and Treatment After SCI Spinal Cord Injury Rehabilitation Pediatric Spinal ...

  6. Spinal Cord Injury 101

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    Full Text Available ... Injury Chart Spinal Cord Injury Facts and Figures Care and Treatment After SCI Spinal Cord Injury Rehabilitation ... Injury Chart Spinal Cord Injury Facts and Figures Care and Treatment After SCI Spinal Cord Injury Rehabilitation ...

  7. Spinal Cord Injury 101

    Medline Plus

    Full Text Available menu Understanding Spinal Cord Injury What is a Spinal Cord Injury Levels of Injury and What They Mean Animated Spinal Cord Injury Chart Spinal Cord Injury Facts and Figures Care and ...

  8. Spinal Cord Injury 101

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    Full Text Available ... Cord Injury Rehabilitation Pediatric Spinal Cord Injuries Video Library SCI Medical Experts People Living with SCI Personal ... Cord Injury Rehabilitation Pediatric Spinal Cord Injuries Video Library SCI Medical Experts People Living with SCI Personal ...

  9. Vocal Cord Paralysis

    Science.gov (United States)

    ... therapy can sometimes be an option. Symptoms Vocal cords open and closed Vocal cords open and closed Your vocal cords are two ... Cardiovascular and Thoracic Research. 2014;6:47. Vocal cord paralysis Symptoms & causes Diagnosis & treatment Doctors & departments Advertisement ...

  10. Precision tethered satellite attitude control. Ph.D. Thesis

    Science.gov (United States)

    Kline-Schoder, Robert J.

    1990-01-01

    Tethered spacecraft possess unique dynamic characteristics which make them advantageous for certain classes of experiments. One use for which tethers are particularly well suited is to provide an isolated platform for spaceborne observatories. The advantages of tethering a pointing platform 1 or 2 km from a space shuttle or space station are that, compared to placing the observatory on the parent spacecraft, vibrational disturbances are attenuated and contamination is eliminated. In practice, all satellites have some requirement on the attitude control of the spacecraft, and tethered satellites are no exception. It has previously been shown that conventional means of performing attitude control for tethered satellites are insufficient for any mission with pointing requirements more stringent than about 1 deg. This is due mainly to the relatively large force applied by the tether to the spacecraft. A particularly effective method of implementing attitude control for tethered satellites is to use this tether tension force to generate control torques by moving the tether attach point relative to the subsatellite center of mass. A demonstration of this attitude control technique on an astrophysical pointing platform has been proposed for a space shuttle flight test project and is referred to as the Kinetic Isolation Tether Experiment (KITE).

  11. Cost-Effectiveness and Cost-Utility Analysis of Spinal Cord Stimulation in Patients With Failed Back Surgery Syndrome: Results From the PRECISE Study.

    Science.gov (United States)

    Zucco, Furio; Ciampichini, Roberta; Lavano, Angelo; Costantini, Amedeo; De Rose, Marisa; Poli, Paolo; Fortini, Gianpaolo; Demartini, Laura; De Simone, Enrico; Menardo, Valentino; Cisotto, Piero; Meglio, Mario; Scalone, Luciana; Mantovani, Lorenzo G

    2015-06-01

    To assess the cost-effectiveness and cost-utility of Spinal Cord Stimulation (SCS) in patients with failed back surgery syndrome (FBSS) refractory to conventional medical management (CMM). We conducted an observational, multicenter, longitudinal ambispective study, where patients with predominant leg pain refractory to CMM expecting to receive SCS+CMM were recruited in 9 Italian centers and followed up to 24 months after SCS. We collected data on clinical status (pain intensity, disability), Health-Related Quality-of-Life (HRQoL) and on direct and indirect costs before (pre-SCS) and after (post-SCS) the SCS intervention. Costs were quantified in € 2009, adopting the National Health Service's (NHS), patient and societal perspectives. Benefits and costs pre-SCS versus post-SCS were compared to estimate the incremental cost-effectiveness and cost utility ratios. 80 patients (40% male, mean age 58 years) were recruited. Between baseline and 24 months post-SCS, clinical outcomes and HRQoL significantly improved. The EQ-5D utility index increased from 0.421 to 0.630 (p costs increased from €6600 (pre-SCS) to €13,200 (post-SCS) per patient per year. Accordingly, the cost-utility acceptability curve suggested that if decision makers' willingness to pay per Quality-Adjusted-Life-Years (QALYs) was €60,000, SCS implantation would be cost-effective in 80% and 85% of cases, according to the NHS's and societal point of views, respectively. Our results suggest that in clinical practice, SCS+CMM treatment of FBSS patients refractory to CMM provides good value for money. Further research is encouraged in the form of larger, long-term studies. © 2015 International Neuromodulation Society.

  12. Tethered constellation, their utilization as microgravity platforms and relevant features

    Science.gov (United States)

    Napolitano, L. G.; Bevilacqua, F.

    1984-10-01

    The gravitational, thermal, and dynamic docking effects on tethered platforms were studied. The near-earth environment has gravitational effects such as g-jitters and intermittencies, g-noise, and frequency and amplitude features which may influence life science, materials processing, and fluid processes research and commercial activities. Artificial gravity is produced by minute accelerations imparted by tethers. The magnitudes of gravitational forces produced by tethers 100 and 100,000 m long at various altitudes from 463-35,786 km are calculated. Thermal analyses were performed for stainless steel and Kevlar tethers, showing the steel tether could vary 300 m in length and the polyamide 25 m during one orbit. Finally, consideration given to docking with a tethered platform revealed that the center of mass could change, which would produce, however, negligible changes in orbit and therefore gravity.

  13. Orbital oscillations of an elastic vertically-tethered satellite

    Science.gov (United States)

    Aslanov, V. S.

    2011-10-01

    The motion of a satellite in a circular orbit with respect to its center of mass is considered. The satellite bears an elastic tether system unrolled along the local vertical. The load at the end of the tether oscillates harmonically. The satellite motion under the action of the gravitational moment and the moment due to the tether tension force is studied. The bifurcation diagram is constructed and the hetero- and homoclinic separatrix trajectories are determined. Mel'nikov's method is used to study the satellite chaotic behavior near separatrices under the action of the periodic tether tension force. The results of the present paper can be used to analyze tether systems of gravitational stabilization and to study the orbital behavior of a satellite with an unrolled tether system with respect to the satellite center of mass.

  14. Cord Blood

    OpenAIRE

    Saeed Abroun

    2014-01-01

      Stem cells are naïve or master cells. This means they can transform into special 200 cell types as needed by body, and each of these cells has just one function. Stem cells are found in many parts of the human body, although some sources have richer concentrations than others. Some excellent sources of stem cells, such as bone marrow, peripheral blood, cord blood, other tissue stem cells and human embryos, which last one are controversial and their use can be illegal in some countries. Cord...

  15. Donor Umbilical Cord Blood Transplant With or Without Ex-vivo Expanded Cord Blood Progenitor Cells in Treating Patients With Acute Myeloid Leukemia, Acute Lymphoblastic Leukemia, Chronic Myelogenous Leukemia, or Myelodysplastic Syndromes

    Science.gov (United States)

    2017-10-24

    Acute Biphenotypic Leukemia; Acute Erythroid Leukemia; Acute Lymphoblastic Leukemia in Remission; Acute Megakaryoblastic Leukemia; Acute Myeloid Leukemia Arising From Previous Myelodysplastic Syndrome; Acute Myeloid Leukemia in Remission; Blasts Under 10 Percent of Bone Marrow Nucleated Cells; Chronic Myelogenous Leukemia, BCR-ABL1 Positive; Mixed Phenotype Acute Leukemia; Myelodysplastic Syndrome; Myelodysplastic Syndrome With Excess Blasts; Pancytopenia; Refractory Anemia; Secondary Acute Myeloid Leukemia

  16. Mazabraud's Syndrome Coexisting with a Uterine Tumor Resembling an Ovarian Sex Cord Tumor (UTROSCT): a Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Calisir, Cuneyt; Inan, Ulukan; Yavas, Ulas Savas; Isiksoy, Serap; Kaya, Tamer [Eskisehir Osmangazi University, Eskiseh (Korea, Republic of)

    2007-10-15

    Intramuscular myxoma is a relatively uncommon benign soft tissue tumor. Its association with fibrous dysplasia of bone represents a rare syndrome described by Mazabraud and Girard in 1957. The relationship between fibrous dysplasia and myxoma remains unclear. A common histogenesis has been proposed for both lesions. Wirth et al. has suggested a basic metabolic error of both tissues during the initial growth period, restricted to the region of bone involvement. Myxomas may appear at any age, but have a predilection for older individuals, occurring most commonly during the sixth and seventh decades of life. They are often located in the large muscles of the thigh, shoulder and buttocks. The majority of intramuscular myxomas are solitary. Cross-sectional techniques are essential in the preoperative planning of excision of soft tissue tumors. The ability to evaluate soft tissue myxomas is best accomplished with MR imaging. Myxomas typically demonstrate the following MR features: very sharply defined contour and homogeneous signal intensity. In particular, the lesions are significantly low in signal intensity on T1-weighted images and high in signal intensity on T2-weighted images. In the patient of this case, the MR appearance was in agreement with previously reported cases.

  17. Nano-mechanics of HaloTag Tethers

    OpenAIRE

    Popa, Ionel; Berkovich, Ronen; Alegre-Cebollada, Jorge; Badilla, Carmen L.; Rivas-Pardo, Jaime Andres; Taniguchi, Yukinori; Kawakami, Masaru; Fernandez, Julio M.

    2013-01-01

    The active site of the Haloalkane Dehydrogenase (HaloTag) enzyme can be covalently attached to a chloroalkane ligand providing a mechanically strong tether, resistant to large pulling forces. Here we demonstrate the covalent tethering of protein L and I27 polyproteins between an AFM cantilever and a glass surface using HaloTag anchoring at one end, and thiol chemistry at the other end. Covalent tethering is unambiguously confirmed by the observation of full length polyprotein unfolding, combi...

  18. Chaotic motions of a tethered satellite system in circular orbit

    Science.gov (United States)

    Jin, D. P.; PANG, Z. J.; Wen, H.; Yu, B. S.

    2016-09-01

    This paper studies the chaotic motions of a tethered satellite system by utilizing a ground-based experimental system. Based on dynamics similarity principle, a dynamical equivalent model between the on-orbit tethered satellite and its ground physical model is obtained. As a result, the space dynamics environment of the tethered satellite can be simulated via the thrust forces and the torque of a momentum wheel on the satellite simulator. The numerical results of the on-orbit tethered satellite show the chaotic motions of the attitude motion of mother satellite. The experiment shows that the torque of momentum wheel as a negative damping is able to suppress the chaotic motion.

  19. Electrodynamic Tether Propulsion for Spacecraft and Upper Stages

    Science.gov (United States)

    Johnson, Les; Gilchrist, Brian; Estes, Robert D.; Lorenzini, Rnrico; Martinez-Sanchez, Manuel; Sanmartin, Juan

    1998-01-01

    Relatively short electrodynamic tethers can use solar power to 'push' against a planetary magnetic field to achieve propulsion without the expenditure of propellant. The groundwork has been laid for this type of propulsion. Important recent milestones include retrieval of a tether in space (TSS-1, 1992), successful deployment of a 20-km-long tether in space (SEDS-1, 1993), and operation of an electrodynamic tether with tether current driven in both directions (PMG, 1993). The planned Propulsive Small Expendable Deployer System (ProSEDS) experiment will use the flight-proven Small Expendable Deployer System (SEDS) to deploy a 5 km bare copper tether from a Delta II upper stage to achieve approximately 0.4 N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of the endmass collector and insulated tether approach used on previous missions. The flight experiment is a precursor to utilization of the technology on the International Space Station for reboost and the electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes, all using electrodynamic thrust. In addition, the use of this type of propulsion may be attractive for future missions at Jupiter.

  20. Lyapunov Orbits in the Jupiter System Using Electrodynamic Tethers

    Science.gov (United States)

    Bokelmann, Kevin; Russell, Ryan P.; Lantoine, Gregory

    2013-01-01

    Various researchers have proposed the use of electrodynamic tethers for power generation and capture from interplanetary transfers. The effect of tether forces on periodic orbits in Jupiter-satellite systems are investigated. A perturbation force is added to the restricted three-body problem model and a series of simplifications allows development of a conservative system that retains the Jacobi integral. Expressions are developed to find modified locations of equilibrium positions. Modified families of Lyapunov orbits are generated as functions of tether size and Jacobi integral. Zero velocity curves and stability analyses are used to evaluate the dynamical properties of tether-modified orbits.

  1. Joint ASI/NASA efforts on tether flight demonstrations

    Science.gov (United States)

    Loria, Alberto; Harrison, James K.

    1989-01-01

    Technological and organizational aspects of joint efforts by NASA and the Italian space agency ASI to develop tethered spacecraft systems are briefly discussed. The members of the ASI/NASA Task Group for Tether Flight Demonstrations are listed; the history of Task Group activities since 1986 is reviewed; and the current status of the main projects is indicated in a series of charts. Particular attention is given to the Tether Initiated Space Recovery System, a 450-lb spacecraft with a 20-km tether scheduled for Space Shuttle or Delta II launch to a 250-km 27.5-deg circular orbit in 1992.

  2. Dynamic control of the space tethered system

    Science.gov (United States)

    Malashin, A. A.; Smirnov, N. N.; Bryukvina, O. Yu.; Dyakov, P. A.

    2017-02-01

    We discuss the problem of simultaneous dynamical stabilization and suppression of transverse and longitudinal vibrations of the space tethered system deployed along a certain trajectory. The dynamics of the system is described by a system of nonlinear partial differential equations for the longitudinal and transverse waves and we consider a non-classical version of the problem with one moving boundary. We formulate a mathematical model and perform the analytic and numerical analysis of the boundary control problem based on the Lyapunov method. A scheme of the deployment mechanism is suggested. It includes a control torque and transverse displacement of the boundary and ensures stable deployment of the whole system.

  3. LUMBAR syndrome: A case manifesting as cutaneous infantile hemangiomas of the lower extremity, perineum and gluteal region, and a review of published work.

    Science.gov (United States)

    Yu, Xia; Zhang, Jia; Wu, Zhouwei; Liu, Ming; Chen, Ruhong; Gu, Yan; Li, Ming; Yao, Zhirong

    2017-07-01

    We herein report a rare case of LUMBAR syndrome. A 1-month-old female infant presented with extensive segmental hemangiomas on the left lower extremity, left perineum and gluteal region with ulceration. Bilateral labia minoras were asymmetrical. Both legs were asymmetrical with left leg atrophy, and the intergluteal cleft was deviated. A dark red pustule and a sacrococcygeal dimple could be seen in the lumbosacral region. Lipomyelomeningocele, tethered cord and sacrum dysplasia were noted by magnetic resonance imaging. The patient was found to have an absent left kidney at 32 weeks of pregnancy. Eventually, we draw the diagnosis of LUMBAR syndrome. In addition, we discuss the clinical manifestation, diagnosis, treatment and pathogenesis by a review of published work. © 2017 Japanese Dermatological Association.

  4. Dorsal Root Ganglion Stimulation as a Salvage Treatment for Complex Regional Pain Syndrome Refractory to Dorsal Column Spinal Cord Stimulation: A Case Series.

    Science.gov (United States)

    Yang, Ajax; Hunter, Corey W

    2017-10-01

    The efficacy of traditional spinal cord stimulation (t-SCS) tends to decay over time in patients with complex regional pain syndrome (CRPS). While it has been shown that dorsal root ganglion (DRG) stimulation is extremely effective in t-SCS-naïve patients with CRPS, its efficacy in patients who had previously failed t-SCS is unknown. Given that DRG-SCS and t-SCS target different spinal pathways, a failure with t-SCS should not automatically preclude a patient from attempting DRG-SCS. Two patients with lower extremity CRPS, previously implanted with t-SCS systems, experienced relapses in the pain despite exhaustive reprogramming. Both patients were offered DRG stimulation as a means to salvage treatment. Patient 1 reported 90% pain reduction with significant gait improvement during the DRG stimulation trial. The patient subsequently proceeded to implant and have the t-SCS implantable pulse generator explanted. Patient 2 was unable to undergo a trial with DRG-SCS because of health insurance constraints, so she elected to undergo a surgical revision of her existing system whereby a DRG-SCS system was added to the existing t-SCS to create a hybrid system with two implantable pulse generators. The patient reported an immediate improvement in pain because of the introduction of the DRG-SCS. Additionally, she was instructed to document her pain scores with each system on individually, as well as with both on-her pain scores were at the lowest with the DRG-SCS on by itself. At eight-month follow-up, both patients reported sustained pain improvement and retained their functional gains. Our case series demonstrates that a failure of t-SCS is not necessarily a failure of neurostimulation as a whole. The efficacy of DRG-SCS is independent of prior t-SCS therapy outcomes in these two patients and a history of t-SCS failure serves no predictive value in these two patients for future DRG stimulation success. Therefore, DRG-SCS can be considered as a reasonable next-step to

  5. Multicolumn spinal cord stimulation for significant low back pain in failed back surgery syndrome: design of a national, multicentre, randomized, controlled health economics trial (ESTIMET Study).

    Science.gov (United States)

    Roulaud, M; Durand-Zaleski, I; Ingrand, P; Serrie, A; Diallo, B; Peruzzi, P; Hieu, P D; Voirin, J; Raoul, S; Page, P; Fontaine, D; Lantéri-Minet, M; Blond, S; Buisset, N; Cuny, E; Cadenne, M; Caire, F; Ranoux, D; Mertens, P; Naous, H; Simon, E; Emery, E; Gadan, B; Regis, J; Sol, J-C; Béraud, G; Debiais, F; Durand, G; Guetarni Ging, F; Prévost, A; Brandet, C; Monlezun, O; Delmotte, A; d'Houtaud, S; Bataille, B; Rigoard, P

    2015-03-01

    Many studies have demonstrated the efficacy of spinal cord stimulation (SCS) for chronic neuropathic radicular pain over recent decades, but despite global favourable outcomes in failed back surgery syndrome (FBSS) with leg pain, the back pain component remains poorly controlled by neurostimulation. Technological and scientific progress has led to the development of new SCS leads, comprising a multicolumn design and a greater number of contacts. The efficacy of multicolumn SCS lead configurations for the treatment of the back pain component of FBSS has recently been suggested by pilot studies. However, a randomized controlled trial must be conducted to confirm the efficacy of new generation multicolumn SCS. Évaluation médico-économique de la STImulation MEdullaire mulTi-colonnes (ESTIMET) is a multicentre, randomized study designed to compare the clinical efficacy and health economics aspects of mono- vs. multicolumn SCS lead programming in FBSS patients with radicular pain and significant back pain. FBSS patients with a radicular pain VAS score≥50mm, associated with a significant back pain component were recruited in 14 centres in France and implanted with multicolumn SCS. Before the lead implantation procedure, they were 1:1 randomized to monocolumn SCS (group 1) or multicolumn SCS (group 2). Programming was performed using only one column for group 1 and full use of the 3 columns for group 2. Outcome assessment was performed at baseline (pre-implantation), and 1, 3, 6 and 12months post-implantation. The primary outcome measure was a reduction of the severity of low back pain (bVAS reduction≥50%) at the 6-month visit. Additional outcome measures were changes in global pain, leg pain, paraesthesia coverage mapping, functional capacities, quality of life, neuropsychological aspects, patient satisfaction and healthcare resource consumption. Trial recruitment started in May 2012. As of September 2013, all 14 study centres have been initiated and 112

  6. Tether enabled spacecraft systems for ultra long wavelength radio astronomy

    Science.gov (United States)

    Gemmer, Thomas; Yoder, Christopher D.; Reedy, Jacob; Mazzoleni, Andre P.

    2017-09-01

    This paper describes a proposed CubeSat mission to perform unique experiments involving interferometry and tether dynamics. A 3U CubeSat is to be placed in orbit where it will separate into three 1U CubeSats connected by a total of 100 m of tether. The separation between the three units will allow for the demonstration of high resolution radio interferometry. The increased resolution will provide access to the Ultra-Long Wavelength (ULW) scale of the electromagnetic spectrum, which is largely unexplored. During and after completion of the primary experiment, the CubeSat will be able to gather data on tethered dynamics of a space vehicle. Maneuvers to be performed and studied include direct testing of tether deployment and tethered formation flying. Tether deployment is a vital area where more data is needed as this is the phase where many tethered missions have experienced complications and failures. There are a large number of complex dynamical responses predicted by the theory associated with the deployment of an orbiting tethered system. Therefore, it is imperative to conduct an experiment that provides data on what dynamic responses actually occur.

  7. Climber Motion Optimization for the Tethered Space Elevator

    NARCIS (Netherlands)

    Williams, P.; Ockels, W.J.

    The tethered space elevator could provide a revolutionary means for enabling cheap transportation to geostationary altitude and beyond. Assuming that such a system can be built, one of the dynamic design problems is determining a means of moving the elevator along the tether so as to minimize the

  8. Effects tethering feeding management system on carcass, organ ...

    African Journals Online (AJOL)

    Sixteen (16) growing West African dwarf goats comprising eight bucks and eight does aged between 8 – 12 months were used in this study to monitor the effect of periodic tethering ... The tethered goats in treatment group T 1 showed higher weight values of the liver (0.95 + 0.1 kg) and kidneys weight of (0.42 + 0.17 kg).

  9. Tethered Contactless Mobile Nuclear Environment Monitoring Robot

    Energy Technology Data Exchange (ETDEWEB)

    Choi, S. Y.; Lee, E. S.; Lee, Kun J.; Kim, Su H.; Rim, C. T. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2013-05-15

    In fact, the nuclear environment monitoring is significantly crucial for early detection of NPP accident, radiological emergency, the estimation of radiation exposure to nearby residents as well as the long term radioactivity. In the UAE, the nuclear environment monitoring is, however, quite challenging because sampling locations are far from NPPs and the outdoor temperature and humidity are very high for NPP workers to collect soil, air, and water samples. Therefore, nuclear environment monitoring robots (Nubos) are strongly needed for the NPPs in the UAE. The Nubos can be remotely controlled to collect samples in extreme environment instead of NPP workers. Moreover, the Nubos can be unmanned ground vehicles (UGVs), unmanned aerial vehicles (UAVs) and unmanned marine vehicles (UMVs) to collect soil, air, and water samples, respectively. In this paper, the prototype development of UGV type Nubos using power cable for a long distance power delivery, called Tethered contactless mobile Nubo is introduced and validated by experiments. In this paper, the prototype development of Tethered Contactless Mobile (TeCoM) Nubo, which can be powered continuously within several km distance and avoid tangled cable, and the indoor test are finished. As further works, outdoor demonstration and a grand scale R and D proposal of practical Nubo will be proceeded.

  10. A space tethered towing method using tension and platform thrusts

    Science.gov (United States)

    Meng, Zhongjie; Wang, Bingheng; Huang, Panfeng

    2017-01-01

    Orbit maneuver via tether is a promising countermeasure for space debris removal and satellite orbit transfer. A space tethered towing method is explored that utilizes thrust to fulfill transfer and bounded tension to stabilize tether heading. For this purpose, a time-energy optimal orbit is designed by Gauss pseudospectral method. The theoretical attitude commands are obtained by equilibria analysis. An effective attitude control strategy is presented where the commands are optimized first and then feedback controller is designed. To deal with the underactuated problem with tension constraint, hierarchical sliding mode theory is employed and an adaptive anti-windup module is added to mitigate the actuator saturation. Simulation results show that the target is towed effectively by the thrusts, and a smooth tracking for the commands of tether length and in-plane tether heading is guaranteed by the bounded tension. In addition, the designed controller also presents appreciable robustness to model error and determination error.

  11. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Cord Injury Diane M. Rowles, MS, NP How Family Life Changes After Spinal Cord Injury Nancy Rosenberg, ... Children with Spinal Cord Injury Patricia Mucia, RN Family Life After Pediatric Spinal Injury Dawn Sheaffer, MSW ...

  12. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Life After Pediatric Spinal Injury Dawn Sheaffer, MSW Rehabilitation Psychological Realities after Spinal Cord Injury Toby Huston, ... Rose, PhD The Basics of Spinal Cord Injury Rehabilitation Kristine Cichowski, MS Occupational Therapy after Spinal Cord ...

  13. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... spinal cord injury? play_arrow What kind of surgery is common after a spinal cord injury? play_ ... How soon after a spinal cord injury should surgery be performed? play_arrow Is it common to ...

  14. Spinal Cord Injury 101

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    Full Text Available ... L Sarah Harrison, OT Anne Bryden, OT The Role of the Social Worker after Spinal Cord Injury ... a spinal cord injury important? play_arrow What role does “compression” play in a spinal cord injury? ...

  15. Spinal Cord Injury 101

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    Full Text Available ... Counseling Blog About Media Donate Spinal Cord Injury Medical Expert Videos Topics menu Topics Spinal Cord Injury ... Jennifer Piatt, PhD David Chen, MD Read Bio Medical Director, Spinal Cord Injury Rehabilitation Program, Rehabilitation Institute ...

  16. Spinal Cord Injury 101

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    Full Text Available ... Spinal Cord Injury Diane M. Rowles, MS, NP How Family Life Changes After Spinal Cord Injury Nancy ... Abuse and Spinal Cord Injury Allen Heinemann, PhD How Peer Counseling Works Julie Gassaway, MS, RN Pediatric ...

  17. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Cord Injury Rehabilitation Pediatric Spinal Cord Injuries Video Library SCI Medical Experts People Living with SCI Personal Experiences by Topic Resources Peer Counseling Blog About Media Donate close search Understanding Spinal Cord Injury What ...

  18. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... About Media Donate Spinal Cord Injury Medical Expert Videos Topics menu Topics Spinal Cord Injury 101 Adult ... LLC Understanding Spinal Cord Injury About Us Expert Videos Contact Us Personal Experience Videos Blog Videos By ...

  19. Spinal Cord Diseases

    Science.gov (United States)

    Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back and ... the spine, this can also injure the spinal cord. Other spinal cord problems include Tumors Infections such ...

  20. Proposed Mechanisms of Tethered Antimicrobial Peptide Chrysophsin-1 as a Function of Tether Length Using QCM-D.

    Science.gov (United States)

    Lozeau, Lindsay D; Alexander, Todd E; Camesano, Terri A

    2015-10-15

    Rising antibiotic resistance has led to a call for the development of alternative antibiotics. Antimicrobial peptides (AMPs) are promising, but their potential has not been fully explored because of toxicity and lack of stability in vivo. Multiple recent studies have focused on surface immobilization of AMPs to maximize antimicrobial activity and stability while mitigating toxicity. We covalently tethered cysteine-modified chrysophsin-1 (C-CHY1) via PEG of three molecular weights, 866, 2000, and 7500. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize thickness and grafting density of tethered C-CHY1, which were related to its activity against Staphylococcus aureus and Escherichia coli and found to be important in determining mechanisms leading to activity. The PEG 866 tether promoted an antimicrobial mechanism that caused displacement of positive cations from bacterial membranes. The PEG 7500 tether maintained C-CHY1's ability to effectively form membrane pores, promoting the highest activity. When AMP was tethered with PEG 2000, antimicrobial activity was limited, apparently because neither mechanism of AMP activity was able to occur with this tether. Using QCM-D, we calculated thickness and density of PEG-tethered C-CHY1 and correlated it with antimicrobial effectiveness to determine the mechanisms by which tethered C-CHY1 acts against bacteria.

  1. Spinal cord contusion

    OpenAIRE

    Ju, Gong; Wang, Jian; Wang, Yazhou; Zhao, Xianghui

    2014-01-01

    Spinal cord injury is a major cause of disability with devastating neurological outcomes and limited therapeutic opportunities, even though there are thousands of publications on spinal cord injury annually. There are two major types of spinal cord injury, transaction of the spinal cord and spinal cord contusion. Both can theoretically be treated, but there is no well documented treatment in human being. As for spinal cord contusion, we have developed an operation with fabulous result.

  2. Changes in Polymeric Tether Properties Due to Atomic Oxygen

    Science.gov (United States)

    Finckenor, Miria M.; Vaughn, Jason A.; Watts, Edward W.

    2003-01-01

    The Propulsive Small Expendable Deployer System (ProSEDS) mission is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta II unmanned expendable booster. A 5-km conductive tether is attached to the Delta II second stage and collects current fiom the low Earth orbit (LEO) plasma to facilitate de-orbit of the spent stage. The conductive tether is attached to a 10-km non-conductive tether, which is then attached to an endmass containing several scientific instruments. Atomic oxygen (AO) erodes most organic materials. As the orbit of the Delta II second stage decas, the AO flux (atoms/sq cm sec) increases. A nominal AO fluence of 1 x l0(exp 21) atoms/sq cm was agreed upon by the investigators as an adequate level for evaluating the performance of the tether materials. A test series was performed to determine the effect of atomic oxygen (AO) on the mechanical integrity and possible strength loss of ProSEDS tether materials. The tether materials in this study were Dyneema, an ultra-high molecular weight polyethylene material used as the non-conducting portion of the ProSEDS tether, and the Kevlar core strength fiber used in the conductive tether. Samples of Dyneema and Kevlar were exposed to various levels of atomic oxygen up to 1.07 x 10(exp 21) atoms/sq cm in the Marshall Space Flight Center Atomic Oxygen Beam Facility (AOBF). Changes in mass were noted after AO exposure. The tethers were then tensile-tested until failure. AO affected both the Dyneema and Kevlar tether material strength. Dyneema exposed to 1.07 x 10(exp 21) atoms/sq cm of atomic oxygen failed due to normal handling when removed fiom the AOBF and was not tensile-tested. Another test series was performed to determine the effect of AO on the electrical properties of the ProSEDS conductive tether. The conductive tether consists of seven individually coated strands of 28 AWG 1350

  3. Assessing Tether Anchor Labeling and Usability in Pickup Trucks.

    Science.gov (United States)

    Klinich, Kathleen D; Manary, Miriam A; Malik, Laura A; Flannagan, Carol A; Jermakian, Jessica S

    2017-10-30

    Investigate vehicle factors associated with child restraint tether use and misuse in pickup trucks and evaluate four labeling interventions designed to educate consumers on proper tether use. Volunteer testing was performed with 24 subjects and four different pickup trucks. Each subject performed eight child restraint installations among the four pickups using two forward-facing restraints: a Britax Marathon G4.1 and an Evenflo Triumph. Vehicles were selected to represent four different implementations of tether anchors among pickups: plastic loop routers (Chevrolet Silverado), webbing routers (Ram), back wall anchors (Nissan Frontier), and webbing routers plus metal anchors (Toyota Tundra). Interventions included a diagram label, QR Code linked to video instruction, coordinating text label, and contrasting text tag. Subjects used the child restraint tether in 93 percent of trials. However, tether use was completely correct in only 9 percent of trials. An installation was considered functional if the subject attached the tether to a tether anchor and had a tight installation (ignoring routing and head restraint position); 28 percent of subjects achieved a functional installation. The most common installation error was attaching the tether hook to the anchor/router; directly behind the child restraint (near the top of the seatback) rather than placing the tether through the router and attaching it to the anchor in the adjacent seating position. The Nissan Frontier, with the anchor located on the back wall of the cab, had the highest rate of correct installations but also had the highest rate of attaching the tether to components other than the tether anchor (seat adjustor, child restraint storage hook, around head restraint). None of the labeling interventions had a significant effect on correct installation; not a single subject scanned the QR Code to access the video instruction. Subjects with the most successful installations spent extensive time reviewing the

  4. Project 'VOLCANO': Electronics of tethered satellite system

    Science.gov (United States)

    Savich, N. A.

    The main goal of the 'VOLCANO' project developed jointly by the Institute of Radio Engineering and Electronics and space concern 'ENERGIA' is experimental investigation of the current-voltage characteristics of the 'Collector-Boom-Emitter' system simulating the long Tethered Satellite System (TSS) in the real space flight conditions on the transport ship 'PROGRESS'. These measurements will allow scientists to determine the attainable current values for different combinations of collectors and emitters (passive metallic sphere, thermocathode, hollow cathodes and show up some prospects of active TSS. The report is concerned with the concept, purpose and tasks of the project, the planned set up of the measurement equipment on the 'PROGRESS' ship and in the container extended on the deployable 100 m long boom end.

  5. Interaction of the Space Shuttle on-orbit autopilot with tether dynamics

    Science.gov (United States)

    Bergmann, Edward V.

    1988-01-01

    The effect of Orbiter flight control on tether dynamics is studied by simulation. Open-loop effects of Orbiter jet firing on tether dynamics are shown, and the potential for closed-loop interaction between tether dynamics and Orbiter flight control is determined. The significance of these effects on Orbiter flight control and tether control is assessed.

  6. Passivity-Based Control of a Rigid Electrodynamic Tether

    DEFF Research Database (Denmark)

    Larsen, Martin Birkelund; Blanke, Mogens

    2011-01-01

    parts, a feedback connection, which stabilizes the open-loop equilibrium, and a bias term, which is able to drive the system trajectory away from this equilibrium, a feature necessary to obtain orbit adjustment capabilities of the electrodynamic tether. It is then shown how the periodic solutions......Electrodynamic tethers provide actuation for performing orbit correction of spacecrafts. When an electrodynamic tether system is orbiting the Earth in an inclined orbit, periodic changes in the magnetic field result in a family of unstable periodic solutions in the attitude motion. This paper shows...

  7. Neuropraxia of the cervical spinal cord following cervical spinal cord trauma: a report of five patients.

    Science.gov (United States)

    Bernsen, H J; Koetsveld, A; Frenken, C W; van Norel, G J

    2000-06-01

    Neuropraxia of the cervical spinal cord is a rare condition which is almost exclusively reported in American football players following cervical hyperextension or hyperflexion trauma. In this entity-neurological symptoms of both arms and legs for a period of up to 15 minutes are observed with complete recovery. We report the characteristics of five patients not involved in contact sport activities with a neuropraxia of the spinal cord following cervical trauma. In four of the five patients, this syndrome was associated with a cervical canal stenosis. Surgical decompression was performed in two patients with progressive neurological symptoms after an initial period of recovery. The cases illustrates that although neuropraxia of the spinal cord is usually seen in athletes, also other persons may be at risk for developing this condition, especially when a preexisting spinal stenosis is present. Patients who experienced neuropraxia of the spinal cord should thus be evaluated carefully for the presence of cervical spinal cord abnormalities.

  8. Braided multi-electrode probes: mechanical compliance characteristics and recordings from spinal cords

    Science.gov (United States)

    Kim, Taegyo; Branner, Almut; Gulati, Tanuj; Giszter, Simon F.

    2013-08-01

    Objective. To test a novel braided multi-electrode probe design with compliance exceeding that of a 50 µm microwire, thus reducing micromotion- and macromotion-induced tissue stress. Approach. We use up to 24 ultra-fine wires interwoven into a tubular braid to obtain a highly flexible multi-electrode probe. The tether-portion wires are simply non-braided extensions of the braid structure, allowing the microprobe to follow gross neural tissue movements. Mechanical calculation and direct measurements evaluated bending stiffness and axial compression forces in the probe and tether system. These were compared to 50 µm nichrome microwire standards. Recording tests were performed in decerebrate animals. Main results. Mechanical bending tests on braids comprising 9.6 or 12.7 µm nichrome wires showed that implants (braided portions) had 4 to 21 times better mechanical compliance than a single 50 µm wire and non-braided tethers were 6 to 96 times better. Braided microprobes yielded robust neural recordings from animals' spinal cords throughout cord motions. Significance. Microwire electrode arrays that can record and withstand tissue micro- and macromotion of spinal cord tissues are demonstrated. This technology may provide a stable chronic neural interface into spinal cords of freely moving animals, is extensible to various applications, and may reduce mechanical tissue stress.

  9. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Facts and Figures Care and Treatment After SCI Spinal Cord Injury Rehabilitation Pediatric Spinal Cord Injuries Video Library SCI Medical ... Facts and Figures Care and Treatment After SCI Spinal Cord Injury Rehabilitation Pediatric Spinal Cord Injuries Video Library SCI Medical ...

  10. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... is a spinal cord injury? play_arrow How does the spinal cord work? play_arrow Why is ... spinal cord injury important? play_arrow What role does “compression” play in a spinal cord injury? play_ ...

  11. Symptomatic epidural lipomatosis of the spinal cord in a child: MR demonstration of spinal cord injury

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Alberto [Department of Radiology, Section of Neuroradiology, 505 Parnassus Av, L-371, University of California-San Francisco, CA 94143-0628 (United States); Servicio de Radiodiagnostico, Seccion de Neurorradiologia, Hospital Universitario ' ' 12 de Octubre' ' , 28040 Madrid (Spain); Barkovich, James A. [Department of Radiology, Section of Neuroradiology, 505 Parnassus Av, L-371, University of California-San Francisco, CA 94143-0628 (United States); Mateos, Fernando; Simon, Rogelio [Seccion de Neurpediatria, Servicio de Neurologia, Hospital Universitario ' ' 12 de Octubre' ' , 28041 Madrid (Spain)

    2002-12-01

    We report a case of symptomatic epidural lipomatosis in an 8-year-old girl with Cushing's syndrome secondary to longstanding high-dose steroid therapy for Crohn's disease. MR imaging of the spine revealed massive diffuse epidural fat compressing the entire spinal cord with T2 prolongation in the central gray matter of the cord suggesting ischemic myelopathy. This finding has not been previously demonstrated on imaging. A proposed mechanism underlying these findings is discussed. (orig.)

  12. Infantile Hemophagocytic Lymphohistiocytosis in a Case of Chediak-Higashi Syndrome Caused by a Mutation in the LYST/CHS1 Gene Presenting With Delayed Umbilical Cord Detachment and Diarrhea

    DEFF Research Database (Denmark)

    Nielsen, Christian; Agergaard, Charlotte N; Jakobsen, Marianne A

    2015-01-01

    perforin content in CD8 T cells seems to correlate to the immune activation state of the patient with 82% and 8% perforin-containing CD8 T cells at active and nonactive hemophagocytic lymphohistiocytosis (HLH) disease, respectively. HLH was confirmed by hemophagocytosis in bone marrow and absent natural...... killer cell activity. The patient carried a homozygous G>A mutation in the 3' splice site of intron 24 of the LYST/CHS1 gene, leading to the use of an alternative YAG splice site located in exon 25, introducing a premature STOP codon (L2355fsX2370; NP_000072.2). The early-onset accelerated phase...... in this severe phenotype of Chediak-Higashi syndrome was probably induced by rotaviral infection. Interestingly, the intracellular perforin content in CD8 T cells seems to correlate to the immune activation state of the patient. Late separation of the umbilical cord in concordance with clinical symptoms should...

  13. Fiber Optic Shape Sensing for Tethered Marsupial Rovers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Building upon the successful proof of concept work in Phase I, Luna Innovations Incorporated is proposing to design, build, and test a sensing tether for marsupial...

  14. An updated review of nanotechnologies for the space elevator tether

    OpenAIRE

    Brambilla, G.

    2010-01-01

    The space elevator tether requires an extraordinary specific ultimate strength (ratio between ultimate strength and density) and carbon nanotubes (CNTs) have been identified as the ideal candidate because of their astonishing strength. This paper reviews CNT manufacture and measured strengths.

  15. Fiber Optic Shape Sensing for Tethered Marsupial Rovers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna Innovations Incorporated is proposing to design, build, and test a shape, length, and tension sensing tether for robotic exploration and sample-gathering...

  16. Stationary Tether Device for Buoy Apparatus and System for Using

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A rigid, neutrally buoyant hydrodynamicaly-faired tether and associated fastening hardware that loosely holds a bathymetric float at a predetermined distance from a...

  17. Reconstitution of Cholesterol-Dependent Vaginolysin into Tethered Phospholipid Bilayers

    DEFF Research Database (Denmark)

    Budvytyte, Rima; Pleckaityte, M.; Zvirbliene, A.

    2013-01-01

    Functional reconstitution of the cholesterol-dependent cytolysin vaginolysin (VLY) from Gardnerella vaginalis into artificial tethered bilayer membranes (tBLMs) has been accomplished. The reconstitution of VLY was followed in real-time by electrochemical impedance spectroscopy (EIS). Changes...

  18. Development of a Tethered Formation Flight Testbed for ISS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of a testbed for the development and demonstration of technologies needed by tethered formation flying satellites is proposed. Such a testbed would...

  19. Precession and circularization of elliptical space-tether motion

    Science.gov (United States)

    Chapel, Jim D.; Grosserode, Patrick

    1993-01-01

    In this paper, we present a simplified analytic model for predicting motion of long space tethers. The perturbation model developed here addresses skip rope motion, where each end of the tether is held in place and the middle of the tether swings with a motion similar to that of a child's skip rope. If the motion of the tether midpoint is elliptical rather than circular, precession of the ellipse complicates the procedures required to damp this motion. The simplified analytic model developed in this paper parametrically predicts the precession of elliptical skip rope motion. Furthermore, the model shows that elliptic skip rope motion will circularize when damping is present in the longitudinal direction. Compared with high-fidelity simulation results, this simplified model provides excellent predictions of these phenomena.

  20. Tethered catalysts for the hydration of carbon dioxide

    Science.gov (United States)

    Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

    2014-11-04

    A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

  1. The effects of tether placement on antibody stability on surfaces

    Science.gov (United States)

    Grawe, Rebecca W.; Knotts, Thomas A.

    2017-06-01

    Despite their potential benefits, antibody microarrays have fallen short of performing reliably and have not found widespread use outside of the research setting. Experimental techniques have been unable to determine what is occurring on the surface of an atomic level, so molecular simulation has emerged as the primary method of investigating protein/surface interactions. Simulations of small proteins have indicated that the stability of the protein is a function of the residue on the protein where a tether is placed. The purpose of this research is to see whether these findings also apply to antibodies, with their greater size and complexity. To determine this, 24 tethering locations were selected on the antibody Protein Data Bank (PDB) ID: 1IGT. Replica exchange simulations were run on two different surfaces, one hydrophobic and one hydrophilic, to determine the degree to which these tethering sites stabilize or destabilize the antibody. Results showed that antibodies tethered to hydrophobic surfaces were in general less stable than antibodies tethered to hydrophilic surfaces. Moreover, the stability of the antibody was a function of the tether location on hydrophobic surfaces but not hydrophilic surfaces.

  2. Rate limit of protein elastic response is tether dependent

    Science.gov (United States)

    Berkovich, Ronen; Hermans, Rodolfo I.; Popa, Ionel; Stirnemann, Guillaume; Garcia-Manyes, Sergi; Berne, Bruce J.; Fernandez, Julio M.

    2012-01-01

    The elastic restoring force of tissues must be able to operate over the very wide range of loading rates experienced by living organisms. It is surprising that even the fastest events involving animal muscle tissues do not surpass a few hundred hertz. We propose that this limit is set in part by the elastic dynamics of tethered proteins extending and relaxing under a changing load. Here we study the elastic dynamics of tethered proteins using a fast force spectrometer with sub-millisecond time resolution, combined with Brownian and Molecular Dynamics simulations. We show that the act of tethering a polypeptide to an object, an inseparable part of protein elasticity in vivo and in experimental setups, greatly reduces the attempt frequency with which the protein samples its free energy. Indeed, our data shows that a tethered polypeptide can traverse its free-energy landscape with a surprisingly low effective diffusion coefficient Deff ∼ 1,200 nm2/s. By contrast, our Molecular Dynamics simulations show that diffusion of an isolated protein under force occurs at Deff ∼ 108 nm2/s. This discrepancy is attributed to the drag force caused by the tethering object. From the physiological time scales of tissue elasticity, we calculate that tethered elastic proteins equilibrate in vivo with Deff ∼ 104–106 nm2/s which is two to four orders magnitude smaller than the values measured for untethered proteins in bulk. PMID:22895787

  3. Dynamics of the Space Tug System with a Short Tether

    Directory of Open Access Journals (Sweden)

    Jiafu Liu

    2015-01-01

    Full Text Available The dynamics of the space tug system with a short tether similar to the ROGER system during deorbiting is presented. The kinematical characteristic of this system is significantly different from the traditional tethered system as the tether is tensional and tensionless alternately during the deorbiting process. The dynamics obtained based on the methods for the traditional tethered system is not suitable for the space tug system. Therefore, a novel method for deriving dynamics for the deorbiting system similar to the ROGER system is proposed by adopting the orbital coordinates of the two spacecraft and the Euler angles of ROGER spacecraft as the generalized coordinates instead of in- and out-plane librations and the length of the tether and so forth. Then, the librations of the system are equivalently obtained using the orbital positions of the two spacecraft. At last, the geostationary orbit (GEO and the orbit whose apogee is 300 km above GEO are chosen as the initial and target orbits, respectively, to perform the numerical simulations. The simulation results indicate that the dynamics can describe the characteristic of the tether-net system conveniently and accurately, and the deorbiting results are deeply affected by the initial conditions and parameters.

  4. Treating Chronic Pain after Spinal Cord Injury

    Science.gov (United States)

    2016-09-01

    maintained under isoflurane anesthesia while the head was immobilized in a stereotaxic frame and an incision approximately 1 cm in length was made along the...12):818-823. [56] Xu XJ, Hao JX, Aldskogius H, Seiger A, Wiesenfeld-Hallin Z. Chronic pain-related syndrome in rats after ischemic spinal cord

  5. Computerized video analysis of tethered bacteria

    Science.gov (United States)

    Berg, Howard C.; Block, Steven M.; Conley, M. Patricia; Nathan, Andrew R.; Power, John N.; Wolfe, Alan J.

    1987-03-01

    When a flagellar filament of a bacterial cell such as Escherichia coli is fixed to a glass surface, the cell body spins alternately clockwise and counterclockwise at speeds of up to 15 Hz. In cells wild type for chemotaxis, reversals occur about once per second. A typical experiment on bacterial behavior involves data collected from as many as 30 such cells over periods of about an hour. A system is described that makes practical detailed analysis of such a large body of data. Microscopic fields, each containing many tethered cells, were recorded on VHS cassettes with a shuttered multiframe video camera. The tapes were played back through hardware that encoded information from successive images of a given cell and passed that information on to a minicomputer. This computer, following instructions provided in an editing session, identified intervals during which the cell was rotating clockwise, rotating counterclockwise, or remained stationary. Output files were generated listing the times at which transitions between these states occurred and the speeds of the cell averaged over successive time periods. This output was then combined with that from other cells and/or processed by various applications programs.

  6. Miller Fisher Syndrome

    Science.gov (United States)

    ... org Supported by an educational grant from Talecris Biotherapeutics, Center for Science and Education. What Is Miller ... or spinal cord are usually normal. Spinal fluid protein is often elevated. Pure Fisher syndrome is uncommon, ...

  7. Is repair of the protruded meninges sufficient for treatment of meningocele?

    OpenAIRE

    Yun-Hai, Song; Nan, Bao; Ping-Ping, Gao; Bo, Yang; Cheng, Chen

    2015-01-01

    Purpose The present study aimed to investigate the relationship between meningocele and tethered cord syndrome, diagnosis of meningocele associated with tethered cord syndrome, and when to perform surgery and the best surgical procedure. Methods Sixty-nine children with meningocele who were admitted to Shanghai Children?s Medical Center were analyzed. The relationship between meningocele and other lesions causing tethered cord syndrome was studied by combining magnetic resonance imaging (MRI)...

  8. Factors affecting tether use and correct use in child restraint installations.

    Science.gov (United States)

    Jermakian, Jessica S; Klinich, Kathleen D; Orton, Nichole R; Flannagan, Carol A C; Manary, Miriam A; Malik, Laura A; Narayanaswamy, Prabha

    2014-12-01

    Field studies show that top tethers go unused in half of forward-facing child restraint installations. In this study, parent volunteers were asked to use the Lower Anchors and Tethers for Children (LATCH) to install child restraints in several vehicles to identify tether anchor characteristics that are associated with tether use. Thirty-seven volunteers were assigned to four groups. Each group tested two forward-facing child restraints in four of 16 vehicle models. Logistic regression models were used to identify predictors of tether use and correct use. Subjects used the tether in 89% of the 294 forward-facing child restraint installations and attached the tether correctly in 57% of the installations. Tethers were more likely to be used when the anchor was located on the rear deck as typically found in sedans compared with the seatback, floor, or roof. Tethers were less likely to be attached correctly when there was potentially confusing hardware present. No vehicle tether hardware characteristics or vehicle manual directions were associated specifically with correct tether routing and head restraint position. This study provides laboratory evidence that specific vehicle features are associated with tether use and correct use. Modifications to vehicles that make tether anchors easier to find and identify likely will result in increases in tether use and correct use. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Adult idiopathic scoliosis: the tethered spine.

    Science.gov (United States)

    Whyte Ferguson, Lucy

    2014-01-01

    This article reports on an observational and treatment study using three case histories to describe common patterns of muscle and fascial asymmetry in adults with idiopathic scoliosis (IS) who have significant scoliotic curvatures that were not surgically corrected and who have chronic pain. Rather than being located in the paraspinal muscles, the myofascial trigger points (TrPs) apparently responsible for the pain were located at some distance from the spine, yet referred pain to locations throughout the thoracolumbar spine. Asymmetries in these muscles appear to tether the spine in such a way that they contribute to scoliotic curvatures. Evaluation also showed that each of these individuals had major ligamentous laxity and this may also have contributed to development of scoliotic curvatures. Treatment focused on release of TrPs found to refer pain into the spine, release of related fascia, and correction of related joint dysfunction. Treatment resulted in substantial relief of longstanding chronic pain. Treatment thus validated the diagnostic hypothesis that myofascial and fascial asymmetries were to some extent responsible for pain in adults with significant scoliotic curvatures. Treatment of these patterns of TrPs and muscle and fascial asymmetries and related joint dysfunction was also effective in relieving pain in each of these individuals after they were injured in auto accidents. Treatment of myofascial TrPs and asymmetrical fascial tension along with treatment of accompanying joint dysfunction is proposed as an effective approach to treating both chronic and acute pain in adults with scoliosis that has not been surgically corrected. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... of spinal cord injuries? play_arrow What does stem-cell research on animals tell us? play_arrow When can we expect stem-cell treatments to become available for spinal cord injuries? ...

  11. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... play_arrow What are the chances of regaining feeling and mobility after a spinal cord injury? play_arrow How long does it usually take for feeling and movement to return after a spinal cord ...

  12. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Injury Chart Spinal Cord Injury Facts and Figures Care and Treatment After SCI Spinal Cord Injury ... Pressure Sores Mary Zeigler, MS Transition from Hospital to Home Kim Eberhardt Muir, MS Coping with a New ...

  13. Spinal cord stimulation

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007560.htm Spinal cord stimulation To use the sharing features on this page, please enable JavaScript. Spinal cord stimulation is a treatment for pain that uses a ...

  14. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC Understanding Spinal Cord Injury About Us Expert Videos Contact Us Personal Experience Videos Blog Videos By Topic Media Resources Donate to support families facing spinal cord ...

  15. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Gravity Forms. FacingDisability.com is an informational and support website for families facing spinal cord injuries. The ... Blog Videos By Topic Media Resources Donate to support families facing spinal cord injuries Peer Counseling 312- ...

  16. Spinal Cord Dysfunction (SCD)

    Data.gov (United States)

    Department of Veterans Affairs — The Spinal Cord Dysfunction (SCD) module supports the maintenance of local and national registries for the tracking of patients with spinal cord injury and disease...

  17. Cord blood testing

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003403.htm Cord blood testing To use the sharing features on this page, ... the baby to the mother's womb. Cord blood testing can be done to evaluate a newborn's health. ...

  18. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... long does it usually take for feeling and movement to return after a spinal cord injury? play_ ... LLC Understanding Spinal Cord Injury About Us Expert Videos Contact Us Personal Experience Videos Blog Videos By ...

  19. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Experiences by Topic Resources Peer Counseling Blog About Media Donate close search Understanding Spinal Cord Injury What ... Experiences by Topic Resources Peer Counseling Blog About Media Donate Spinal Cord Injury Medical Expert Videos Topics ...

  20. Tethered Pyrotechnic Apparatus for Acquiring a Ground Sample

    Science.gov (United States)

    Jones, Jack; Zimmerman, Wayne; Wu, Jiunn Jenq; Badescu, Mircea; Sherrit, Stewart

    2009-01-01

    A proposed alternative design for the balloon-borne ground-sampling system described in the immediately preceding article would not rely on free fall to drive a harpoonlike sample-collecting device into the ground. Instead, the harpoon-like sample-collecting device would be a pyrotechnically driven, tethered projectile. The apparatus would include a tripod that would be tethered to the gondola. A gun for shooting the projectile into the ground would be mounted at the apex of the tripod. The gun would include an electronic trigger circuit, a chamber at the breech end containing a pyrotechnic charge, and a barrel. A sabot would be placed in the barrel just below the pyrotechnic charge, and the tethered projectile would be placed in the barrel just below the sabot. The tripod feet would be equipped with contact sensors connected to the trigger circuit. In operation, the tripod would be lowered to the ground on its tether. Once contact with the ground was detected by the sensors on all three tripod feet, the trigger circuit would fire the pyrotechnic charge to drive the projectile into the ground. (Requiring contact among all three tripod feet and the ground would ensure that the projectile would be fired into the ground, rather than up toward the gondola or the balloon.) The tethered projectile would then be reeled back up to the gondola for analysis of the sample.

  1. Tethered Nanoparticle–Polymer Composites: Phase Stability and Curvature

    KAUST Repository

    Srivastava, Samanvaya

    2012-04-17

    Phase behavior of poly(ethylene glycol) (PEG) tethered silica nanoparticles dispersed in PEG hosts is investigated using small-angle X-ray scattering. Phase separation in dispersions of densely grafted nanoparticles is found to display strikingly different small-angle X-ray scattering signatures in comparison to phase-separated composites comprised of bare or sparsely grafted nanoparticles. A general diagram for the dispersion state and phase stability of polymer tethered nanoparticle-polymer composites incorporating results from this as well as various other contemporary studies is presented. We show that in the range of moderate to high grafting densities the dispersion state of nanoparticles in composites is largely insensitive to the grafting density of the tethered chains and chemistry of the polymer host. Instead, the ratio of the particle diameter to the size of the tethered chain and the ratio of the molecular weights of the host and tethered polymer chains (P/N) are shown to play a dominant role. Additionally, we find that well-functionalized nanoparticles form stable dispersions in their polymer host beyond the P/N limit that demarcates the wetting/dewetting transition in polymer brushes on flat substrates interacting with polymer melts. A general strategy for achieving uniform nanoparticle dispersion in polymers is proposed. © 2012 American Chemical Society.

  2. Numerical Simulation of Tethered Underwater Kites for Power Generation

    Science.gov (United States)

    Ghasemi, Amirmahdi; Olinger, David; Tryggvason, Gretar

    2015-11-01

    An emerging renewable energy technology, tethered undersea kites (TUSK), which is used to extract hydrokinetic energy from ocean and tidal currents, is studied. TUSK systems consist of a rigid-winged ``kite,'' or glider, moving in an ocean current which is connected by tethers to a floating buoy on the ocean surface. The TUSK kite is a current speed enhancement device since the kite can move in high-speed, cross-current motion at 4-6 times the current velocity, thus producing more power than conventional marine turbines. A computational simulation is developed to simulate the dynamic motion of an underwater kite and extendable tether. A two-step projection method within a finite volume formulation, along with an Open MP acceleration method, is employed to solve the Navier-Stokes equations. An immersed boundary method is incorporated to model the fluid-structure interaction of the rigid kite (with NACA 0012 airfoil shape in 2D and NACA 0021 airfoil shape in 3D simulations) and the fluid flow. PID control methods are used to adjust the kite angle of attack during power (tether reel-out) and retraction (reel-in) phases. Two baseline simulations (for kite motions in two and three dimensions) are studied, and system power output, flow field vorticity, tether tension, and hydrodynamic coefficients (lift and drag) for the kite are determined. The simulated power output shows good agreement with established theoretical results for a kite moving in two-dimensions.

  3. Neuroimaging features of Cornelia de Lange syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, Matthew T. [Department of Radiology, Washington, DC (United States); Nagaraj, Usha D. [Department of Radiology, Washington, DC (United States); Cincinnati Children' s Hospital, Department of Radiology, Cincinnati, OH (United States); Pearl, Phillip L. [Department of Radiology, Washington, DC (United States); Boston Children' s Hospital, Department of Neurology, Boston, MA (United States)

    2015-08-15

    Cornelia de Lange syndrome is a rare genetic disease characterized by distinctive facial dysmorphia and dwarfism. Multiple organ system involvement is typical. Various central nervous system (CNS) aberrations have been described in the pathology literature; however, the spectrum of neuroimaging manifestations is less well documented. To present neuroimaging findings from a series of eight patients with Cornelia de Lange syndrome. The CT/MR database at a single academic children's hospital was searched for the terms ''Cornelia'', ''Brachmann'' and ''de Lange.'' The search yielded 18 exams from 16 patients. Two non-CNS and six exams without available images were excluded. Ten exams from eight patients were evaluated by a board-certified neuroradiologist. All patients had skull base dysplasia, most with an unusual coronal basioccipital cleft (7/8). All brain MR exams showed microcephaly, volume loss and gyral simplification (5/5). Six patients had an absent massa intermedia. Four patients had small globe anterior segments; three had optic pathway hypoplasia. Basilar artery fenestration was present in two patients; vertebrobasilar hypoplasia was present in one patient. The inner ear vestibules were dysplastic in two patients. One patient had pachymeningeal thickening. Spinal anomalies included scoliosis, segmentation anomalies, endplate irregularities, basilar invagination, foramen magnum stenosis and tethered spinal cord. Typical imaging manifestations of Cornelia de Lange syndrome include skull base dysplasia with coronal clival cleft, cerebral and brainstem volume loss, and gyral simplification. Membranous labyrinth dysplasia, anterior segment and optic pathway hypoplasia, basilar artery fenestration, absent massa intermedia and spinal anomalies may also be present. (orig.)

  4. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Cord Injury Allen Heinemann, PhD How Peer Counseling Works Julie Gassaway, MS, RN Pediatric Injuries Pediatric Spinal Cord Injury 101 Lawrence Vogel, MD The Basics of Pediatric SCI Rehabilitation Sara Klaas, MSW Transitions for Children with Spinal Cord Injury Patricia Mucia, RN Family ...

  5. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Lokomat T. George Hornby, PhD, PT Empowering the Patient After Spinal Cord Injury Guy W. Fried, MD Substance Abuse and Spinal Cord Injury Allen Heinemann, PhD How Peer Counseling Works Julie Gassaway, MS, RN Pediatric Injuries Pediatric Spinal Cord Injury 101 Lawrence Vogel, ...

  6. Spinal Cord Injuries

    Science.gov (United States)

    ... forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures or ... down on the nerve parts that carry signals. Spinal cord injuries can be complete or incomplete. With a complete ...

  7. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Cord Injury Diane M. Rowles, MS, NP How Family Life Changes After Spinal Cord Injury Nancy Rosenberg, PsyD ... Children with Spinal Cord Injury Patricia Mucia, RN Family Life After Pediatric Spinal Injury Dawn Sheaffer, MSW Rehabilitation ...

  8. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... cord injuries? play_arrow What are the latest developments in the use of electrical stimulation for spinal cord injuries? play_arrow What is “Braingate” research? play_arrow How would stem-cell therapies work in the treatment of spinal cord injuries? play_ ...

  9. Modeling of tethered satellite formations using graph theory

    DEFF Research Database (Denmark)

    Larsen, Martin Birkelund; Smith, Roy S; Blanke, Mogens

    2011-01-01

    Tethered satellite formations have recently gained increasing attention due to future mission proposals. Several different formations have been investigated for their dynamic properties and control schemes have been suggested. Formulating the equations of motion and investigation which geometries...... satellite formation and proposes a method to deduce the equations of motion for the attitude dynamics of the formation in a compact form. The use of graph theory and Lagrange mechanics together allows a broad class of formations to be described using the same framework. A method is stated for finding...... could form stable formations in space are cumbersome when done at a case to case basis, and a common framework providing a basic model of the dynamics of tethered satellite formations can therefore be advantageous. This paper suggests the use of graph theoretical quantities to describe a tethered...

  10. Reliability of tethered swimming evaluation in age group swimmers.

    Science.gov (United States)

    Amaro, Nuno; Marinho, Daniel A; Batalha, Nuno; Marques, Mário C; Morouço, Pedro

    2014-06-28

    The aim of the present study was to examine the reliability of tethered swimming in the evaluation of age group swimmers. The sample was composed of 8 male national level swimmers with at least 4 years of experience in competitive swimming. Each swimmer performed two 30 second maximal intensity tethered swimming tests, on separate days. Individual force-time curves were registered to assess maximum force, mean force and the mean impulse of force. Both consistency and reliability were very strong, with Cronbach's Alpha values ranging from 0.970 to 0.995. All the applied metrics presented a very high agreement between tests, with the mean impulse of force presenting the highest. These results indicate that tethered swimming can be used to evaluate age group swimmers. Furthermore, better comprehension of the swimmers ability to effectively exert force in the water can be obtained using the impulse of force.

  11. Reliability of Tethered Swimming Evaluation in Age Group Swimmers

    Directory of Open Access Journals (Sweden)

    Amaro Nuno

    2014-07-01

    Full Text Available The aim of the present study was to examine the reliability of tethered swimming in the evaluation of age group swimmers. The sample was composed of 8 male national level swimmers with at least 4 years of experience in competitive swimming. Each swimmer performed two 30 second maximal intensity tethered swimming tests, on separate days. Individual force-time curves were registered to assess maximum force, mean force and the mean impulse of force. Both consistency and reliability were very strong, with Cronbach's Alpha values ranging from 0.970 to 0.995. All the applied metrics presented a very high agreement between tests, with the mean impulse of force presenting the highest. These results indicate that tethered swimming can be used to evaluate age group swimmers. Furthermore, better comprehension of the swimmers ability to effectively exert force in the water can be obtained using the impulse of force.

  12. Progressive coxa vara by eccentric growth tethering in immature pigs.

    Science.gov (United States)

    Chang, Chia-Hsieh; Chi, Chau-Hwa; Lee, Zhon-Liau

    2006-07-01

    The present study tested progressive coxa vara by eccentric growth tethering that might be used to correct coxa valga in cerebral palsy. Eight young pigs received screw fixation at inferior portion of right femoral head at age 4 months and were killed at age 7.25 months for bilateral femurs for comparison. The neck-shaft angle at the tethered side was significantly less than that at the control side (129.8 vs. 138.3 degrees , P<0.05). Histological study showed bony bar formation. Eccentric growth tethering by one screw resulted in a reduction of neck-shaft angle by 8.5 degrees and shortening of femoral length by 4%.

  13. Behavior During Tethered Kicking in Infants With Periventricular Brain Injury.

    Science.gov (United States)

    Campbell, Suzann K; Cole, Whitney; Boynewicz, Kara; Zawacki, Laura A; Clark, April; Gaebler-Spira, Deborah; deRegnier, Raye-Ann; Kuroda, Maxine M; Kale, Dipti; Bulanda, Michele; Madhavan, Sangeetha

    2015-01-01

    To describe behavior of children with periventricular brain injury (PBI) in a tethered-kicking intervention. Sixteen infants with PBI were randomly assigned to exercise or no-training in a longitudinal pilot study. Frequencies of leg movements and interlimb coordination were described from videos at 2 and 4 months' corrected age (CA). Eight of the 13 children (62%) with longitudinal data increased the frequency of leg movements while tethered to a mobile between 2 and 4 months' CA. Movement frequency was correlated with scores on the Test of Infant Motor Performance, but no differences between experimental groups were found. Children with typical development at 12 months' CA increased the proportion of leg movements that were synchronous between 2 and 4 months, as did a child with cerebral palsy in the experimental group. The tethered-kicking intervention facilitates movement in infants with PBI, but effects on development remain to be demonstrated.

  14. An experimental study of tether reel system: A laboratory model

    OpenAIRE

    Yoshimura, Shoichi; Okamoto, Osamu; 吉村 庄市; 岡本 修

    1992-01-01

    A laboratory prototype model of a reel system has been made as the first step of an in-house hardware study of the tether system in space. The model is consisted of two main parts, i. e., a Reel Drum Driving (RDD) unit (25 kg weight) and a Power Supply/Signal Processing (PSSP) unit (32 kg weight). The tether (0.8 mm in diameter and 300 m long) consists of a Kevlar fiber core and a nylon fiber jacket. Following the preliminary functional test, a computer-controlled functional test has been car...

  15. Membrane tethers formed from blood cells with available area and determination of their adhesion energy.

    OpenAIRE

    Hochmuth, Robert M; Marcus, Warren D.

    2002-01-01

    Fundamental to all mammalian cells is the adherence of the lipid bilayer membrane to the underlying membrane associated cytoskeleton. To investigate this adhesion, we physically detach the lipid membrane from the cell by mechanically forming membrane tethers. For the most part these have been tethers formed from either neutrophils or red cells. Here we do a simple thermodynamic analysis of the tether formation process using the entire cell, including tether, as the control volume. For a neutr...

  16. Optimal Trajectories for Tethered Kite Mounted on a Vertical Axis Generator

    NARCIS (Netherlands)

    Williams, P.; Lansdorp, B.; Ockels, W.

    2007-01-01

    Tethered kite technology promises the enable the efficient extraction of energy from high altitude winds. One possible concept for converting the wind energy into electricity is to generate useful work at the ground by using a tether. The tether is able to drive a generator in one of two ways:

  17. Nonlinear Control of Electrodynamic Tether in Equatorial or Somewhat Inclined Orbits

    DEFF Research Database (Denmark)

    Larsen, Martin Birkelund; Blanke, Mogens

    2007-01-01

    This paper applies different control design methods to a tethered satellite system (TSS) to investigate essential control properties of this under-actuated and nonlinear system. When the tether position in the orbit plane is controlled by the tether current, out of orbit plane motions occur...

  18. 75 FR 47316 - Centennial Challenges 2010 Strong Tether Challenge

    Science.gov (United States)

    2010-08-05

    ... Challenge will be conducted at the 2010 Space Elevator Conference held at the Microsoft Conference Center... SPACE ADMINISTRATION Centennial Challenges 2010 Strong Tether Challenge AGENCY: National Aeronautics and Space Administration (NASA). ACTION: Notice. SUMMARY: This notice is issued in accordance with 42 U.S.C...

  19. 76 FR 41526 - Centennial Challenges 2011 Strong Tether Challenge

    Science.gov (United States)

    2011-07-14

    ... Challenge will be conducted at the 2011 Space Elevator Conference held at the Microsoft Conference Center... SPACE ADMINISTRATION Centennial Challenges 2011 Strong Tether Challenge AGENCY: National Aeronautics and Space Administration (NASA). ACTION: Notice. SUMMARY: This notice is issued in accordance with 42 U.S.C...

  20. Three dimensional dynamics of a flexible Motorised Momentum Exchange Tether

    Science.gov (United States)

    Ismail, N. A.; Cartmell, M. P.

    2016-03-01

    This paper presents a new flexural model for the three dimensional dynamics of the Motorised Momentum Exchange Tether (MMET) concept. This study has uncovered the relationships between planar and nonplanar motions, and the effect of the coupling between these two parameters on pragmatic circular and elliptical orbits. The tether sub-spans are modelled as stiffened strings governed by partial differential equations of motion, with specific boundary conditions. The tether sub-spans are flexible and elastic, thereby allowing three dimensional displacements. The boundary conditions lead to a specific frequency equation and the eigenvalues from this provide the natural frequencies of the orbiting flexible motorised tether when static, accelerating in monotonic spin, and at terminal angular velocity. A rotation transformation matrix has been utilised to get the position vectors of the system's components in an assumed inertial frame. Spatio-temporal coordinates are transformed to modal coordinates before applying Lagrange's equations, and pre-selected linear modes are included to generate the equations of motion. The equations of motion contain inertial nonlinearities which are essentially of cubic order, and these show the potential for intricate intermodal coupling effects. A simulation of planar and non-planar motions has been undertaken and the differences in the modal responses, for both motions, and between the rigid body and flexible models are highlighted and discussed.

  1. Tethered Nanoparticle -Polymer Composites: Phase behavior and rheology

    Science.gov (United States)

    Mangal, Rahul; Archer, Lynden A.

    2014-03-01

    Polymer nanocomposites with particle radius (a) approaching the radius of gyration (Rg) of entangled host polymer have been reported to exhibit an unusual negative reinforcement effect, which leads to an anomalous reduction in relative an anomalous reduction in relative viscosity at low particle loadings (φ) . This so-called Non-Einsteinian flow behavior is understood to be sensitive to the dispersion state of particles in host polymer. We studied suspensions of SiO2 nanoparticles tethered with polethylene glycol (PEG) in polymethylmethacralate (PMMA) with molecular weights (Mw) from 17 KDa to 280 KDa. Due to strong enthalpic interactions between PEG and PMMA (χ = -0.65), nanoparticles are expected to be well-dispersed, independent of Mw of PMMA. Using small angle x-ray scattering measurements we show that the phase stability of suspensions depends on Mw of the tethered PEG, host PMMA, and φ. Particles functionalized with low molecular weight PEG aggregate at low φ, but disperse at high φ. In contrast, nanoparticles functionalized with higher molecular weight PEG are well dispersed for host chain lengths (P) to tethered chain length (N), (P/N), is as high as 160. The stability boundary of these suspensions extends well beyond expectations for nanocomposites based on tethered PEG chains suspended in PEG. Through in-depth analysis of rheology and x-ray photon correlation spectra we explore the fundamental origins of non-Einsteinian flow behavior. King Abdullah University of Science and Technology (KAUST), Advanced Photon Source (APS).

  2. Power and charge dissipation from an electrodynamic tether

    Science.gov (United States)

    Hite, Gerald E.

    1987-01-01

    The Plasma Motor-Generator project utilizes the influence of the geomagnetic field on a conductive tether attached to a LEO spacecraft to provide a reversible conversion of orbital energy into electrical energy. The behavior of the current into the ionospheric plasma under the influence of the geomagnetic field is of significant experimental and theoretical interest. Theoretical calculations are reviewed which start from Maxwell's equations and treat the ionospheric plasma as a linear dielectric medium. These calculations show a charge emitting tether moving in a magnetic field will generate electromagnetic waves in the plasma which carry the charge in the direction of the magnetic field. The ratio of the tether's speed to the ion cyclotron frequency which is about 25 m for a LEO is a characteristic length for the phenomena. Whereas for the dimensions of the contact plasma much larger than this value the waves are the conventional Alfven waves, when the dimensions are comparable or smaller, diffraction effects occur similar to those associated with Fresnel diffraction in optics. The power required to excite these waves for a given tether current is used to estimate the impedance associated with this mode of charge dissipation.

  3. Metal-ligand cooperation at tethered pi-ligands

    NARCIS (Netherlands)

    Verhoeven, Dide G. A.; Moret, Marc-Etienne

    2016-01-01

    Metal–ligand cooperativity in homogeneous catalysis is emerging as a powerful tool for the design of efficient transition-metal catalysts. This perspective highlights recent advances in the use of neutral π-coordinating ligands, tethered to a transition-metal center by other donor ligands, as

  4. Hierarchical Structure in Semicrystalline Polymers Tethered to Nanospheres

    KAUST Repository

    Kim, Sung A

    2014-01-28

    We report on structural and dynamic transitions of polymers tethered to nanoparticles. In particular, we use X-ray diffraction, vibrational spectroscopy, and thermal measurements to investigate multiscale structure and dynamic transitions of poly(ethylene glycol) (PEG) chains densely grafted to SiO2 nanoparticles. The approach used for synthesizing these hybrid particles leads to homogeneous SiO2-PEG composites with polymer grafting densities as high as 1.5 chains/nm2, which allows the hybrid materials to exist as self-suspended suspensions with distinct hierarchical structure and thermal properties. On angstrom and nanometer length scales, the tethered PEG chains exhibit more dominant TTG conformations and helix unit cell structure, in comparison to the untethered polymer. The nanoparticle tethered PEG chains are also reported to form extended crystallites on tens of nanometers length scales and to exhibit more stable crystalline structure on small dimensions. On length scales comparable to the size of each hybrid SiO 2-PEG unit, the materials are amorphous presumably as a result of the difficulty fitting the nanoparticle anchors into the PEG crystal lattice. This structural change produces large effects on the thermal transitions of PEG molecules tethered to nanoparticles. © 2014 American Chemical Society.

  5. Nano-mechanics of HaloTag Tethers

    Science.gov (United States)

    Popa, Ionel; Berkovich, Ronen; Alegre-Cebollada, Jorge; Badilla, Carmen L.; Rivas-Pardo, Jaime Andres; Taniguchi, Yukinori; Kawakami, Masaru; Fernandez, Julio M.

    2013-01-01

    The active site of the Haloalkane Dehydrogenase (HaloTag) enzyme can be covalently attached to a chloroalkane ligand providing a mechanically strong tether, resistant to large pulling forces. Here we demonstrate the covalent tethering of protein L and I27 polyproteins between an AFM cantilever and a glass surface using HaloTag anchoring at one end, and thiol chemistry at the other end. Covalent tethering is unambiguously confirmed by the observation of full length polyprotein unfolding, combined with high detachment forces that range up to ~2000 pN. We use these covalently anchored polyproteins to study the remarkable mechanical properties of HaloTag proteins. We show that the force that triggers unfolding of the HaloTag protein exhibits a four-fold increase, from 131 pN to 491 pN, when the direction of the applied force is changed from the C-terminus to the N-terminus. Force-clamp experiments reveal that unfolding of the HaloTag protein is twice more sensitive to pulling force compared to protein L, and refolds at a slower rate. We show how these properties allow for the long-term observation of protein folding-unfolding cycles at high forces, without interference from the HaloTag tether. PMID:23909704

  6. Fortissimo: A Japanese Space Test Of Bare Wire Anode Tethers

    Science.gov (United States)

    Johnson, Les; Fujii, H. A.; Sanmartin, J. R.

    2008-01-01

    A Japanese led international team is developing a suborbital test of orbital-motion-limited (OML) bare wire anode current collection for application to electrodynamic tether (EDT) propulsion. The tether is a tape with a width of 25 mm, thickness of 0.05 mm, and is 300 m in length. This will be the first space test of OML theory. The mission will launch in the summer of 2009 using an S520 Sounding Rocket. During ascent, and above approx. 100 km in attitude, the tape tether will be deployed at a rate of approx. 8 m/s. Once deployed, the tape tether will serve as an anode, collecting ionospheric electrons. The electrons will be expelled into space by a hollow cathode device, thereby completing the circuit and allowing current to flow. The total amount of current collected will be used to assess the validity of OML theory. This paper will describe the objectives of the proposed mission, the technologies to be employed, and the application of the results to future space missions using EDTs for propulsion or power generation.

  7. Flight control and stability of a multiple kites tethered system

    NARCIS (Netherlands)

    Podgaets, A.R.; Ockels, W.J.

    2006-01-01

    One of novel concepts to use the energy of high altitude winds is by launching a series of kite on a long rope and let them pull the rope thus driving the generator. A mathematical model of tethered kites system has been developed consisting of models of kites and of the cable that links them

  8. Position Control of an X4-Flyer Using a Tether

    Directory of Open Access Journals (Sweden)

    , Keigo Watanabe

    2014-10-01

    Full Text Available In Japan, aging of infrastructures, such as roads, bridges, and water and sewer services, etc. poses a problem, and it is required to extend the life-span of such infrastructures by maintenance. Among infrastructures, especially bridges are periodically inspected by short range visual observations, which check the damage and deterioration of the surface. However, since there are some cases where the short range visual observation is difficult, an alternative method is required so as to replace the short range visual observation with it. So, "X4-Flyer" is very attractive because of realizing a movement at high altitude easily. The objective of this study is to develop a tethered X4- Flyer, so that the conventional short range visual observation of bridges is replaced by it. In this paper, a method for the measurement and control of the position is described by using a tether for controlling the position of the X4-Flyer. In addition, it is checked whether the tethered X4-Flyer can control the position using the proposed method or not, letting it fly in a state in which a tether is being attached.

  9. Spinal cord stimulation for complex regional pain syndrome type 1 with dystonia: a case report and discussion of the literature [v1; ref status: indexed, http://f1000r.es/348

    Directory of Open Access Journals (Sweden)

    Caroline Voet

    2014-04-01

    Full Text Available Background: Complex Regional Pain Syndrome type 1 (CRPS-1 is a debilitating chronic pain disorder, the physiopathology of which can lead to dystonia associated with changes in the autonomic, central and peripheral nervous system. An interdisciplinary approach (pharmacological, interventional and psychological therapies in conjunction with a rehabilitation pathway is central to progress towards pain reduction and restoration of function. Aim: This case report aims to stimulate reflection and development of mechanism-based therapeutic strategies concerning CRPS associated with dystonia. Case description: A 31 year old female CRPS-1 patient presented with dystonia of the right foot following ligamentoplasty for chronic ankle instability. She did not have a satisfactory response to the usual therapies. Multiple anesthetic blocks (popliteal, epidural and intrathecal were not associated with significant anesthesia and analgesia. Mobilization of the foot by a physiotherapist was not possible. A multidisciplinary approach with psychological support, physiotherapy and spinal cord stimulation (SCS brought pain relief, rehabilitation and improvement in the quality of life. Conclusion: The present case report demonstrates the occurrence of multilevel (peripheral and central pathological modifications in the nervous system of a CRPS-1 patient with dystonia. This conclusion is based on the patient’s pain being resistant to anesthetic blocks at different levels and the favourable, at least initially, response to SCS. The importance of the bio-psycho-social model is also suggested, permitting behavioural change.

  10. T-Rex: A Japanese Space Tether Experiment

    Science.gov (United States)

    Johnson, Les

    2009-01-01

    Electrodynamic tether (EDT) thrusters work by virtue of the force a magnetic field exerts on a wire carrying an electrical current. The force, which acts on any charged particle moving through a magnetic field (including the electrons moving in a current-carrying wire), were concisely expressed by Lorentz in 1895 in an equation that now bears his name. The force acts in a direction perpendicular to both the direction of current flow and the magnetic field vector. Electric motors make use of this force: a wire loop in a magnetic field is made to rotate by the torque the Lorentz Force exerts on it due to an alternating current in the loop times so as to keep the torque acting in the same sense. The motion of the loop is transmitted to a shaft, thus providing work. Although the working principle of EDT thrusters is not new, its application to space transportation may be significant. In essence, an EDT thruster is just a clever way of getting an electrical current to flow in a long orbiting wire (the tether) so that the Earth s magnetic field will accelerate the wire and, consequently the payload attached to the wire. The direction of current flow in the tether, either toward or away from the Earth along the local vertical, determines whether the magnetic force will raise or lower the orbit. The bias voltage of a vertically deployed metal tether, which results just from its orbital motion (assumed eastward) through Earth s magnetic field, is positive with respect to the ambient plasma at the top and negative at the bottom. This polarization is due to the action of the Lorentz force on the electrons in the tether. Thus, the natural current flow is the result of negative electrons being attracted to the upper end and then returned to the plasma at the lower end. The magnetic force in this case has a component opposite to the direction of motion, and thus leads to a lowering of the orbit and eventually to re-entry. In this generator mode of operation the Lorentz Force

  11. Autonomous Vision-Based Tethered-Assisted Rover Docking

    Science.gov (United States)

    Tsai, Dorian; Nesnas, Issa A.D.; Zarzhitsky, Dimitri

    2013-01-01

    Many intriguing science discoveries on planetary surfaces, such as the seasonal flows on crater walls and skylight entrances to lava tubes, are at sites that are currently inaccessible to state-of-the-art rovers. The in situ exploration of such sites is likely to require a tethered platform both for mechanical support and for providing power and communication. Mother/daughter architectures have been investigated where a mother deploys a tethered daughter into extreme terrains. Deploying and retracting a tethered daughter requires undocking and re-docking of the daughter to the mother, with the latter being the challenging part. In this paper, we describe a vision-based tether-assisted algorithm for the autonomous re-docking of a daughter to its mother following an extreme terrain excursion. The algorithm uses fiducials mounted on the mother to improve the reliability and accuracy of estimating the pose of the mother relative to the daughter. The tether that is anchored by the mother helps the docking process and increases the system's tolerance to pose uncertainties by mechanically aligning the mating parts in the final docking phase. A preliminary version of the algorithm was developed and field-tested on the Axel rover in the JPL Mars Yard. The algorithm achieved an 80% success rate in 40 experiments in both firm and loose soils and starting from up to 6 m away at up to 40 deg radial angle and 20 deg relative heading. The algorithm does not rely on an initial estimate of the relative pose. The preliminary results are promising and help retire the risk associated with the autonomous docking process enabling consideration in future martian and lunar missions.

  12. Relaxation Dynamics of Nanoparticle-Tethered Polymer Chains

    KAUST Repository

    Kim, Sung A

    2015-09-08

    © 2015 American Chemical Society. Relaxation dynamics of nanoparticle-tethered cis-1,4-polyisoprene (PI) are investigated using dielectric spectroscopy and rheometry. A model system composed of polymer chains densely grafted to spherical SiO2 nanoparticles to form self-suspended suspensions facilitates detailed studies of slow global chain and fast segmental mode dynamics under surface and geometrical confinement-from experiments performed in bulk materials. We report that unentangled polymer molecules tethered to nanoparticles relax far more slowly than their tethered entangled counterparts. Specifically, at fixed grafting density we find, counterintuitively, that increasing the tethered polymer molecular weight up to values close to the entanglement molecular weight speeds up chain relaxation dynamics. Decreasing the polymer grafting density for a fixed molecular weight has the opposite effect: it dramatically slows down chain relaxation, increases interchain coupling, and leads to a transition in rheological response from simple fluid behavior to viscoelastic fluid behavior for tethered PI chains that are unentangled by conventional measures. Increasing the measurement temperature produces an even stronger elastic response and speeds up molecular relaxation at a rate that decreases with grafting density and molecular weight. These observations are discussed in terms of chain confinement driven by crowding between particles and by the existence of an entropic attractive force produced by the space-filling constraint on individual chains in a self-suspended material. Our results indicate that the entropic force between densely grafted polymer molecules couples motions of individual chains in an analogous manner to reversible cross-links in associating polymers.

  13. Modelling a tethered mammalian sperm cell undergoing hyperactivation

    KAUST Repository

    Curtis, M.P.

    2012-09-01

    The beat patterns of mammalian sperm flagella can be categorised into two different types. The first involves symmetric waves propagating down the flagellum with a net linear propulsion of the sperm cell. The second, hyperactive, waveform is classified by vigorous asymmetric waves of higher amplitude, lower wavenumber and frequency propagating down the flagellum resulting in highly curved trajectories. The latter beat pattern is part of the capacitation process whereby sperm prepare for the prospective penetration of the zona pellucida and fusion with the egg. Hyperactivation is often observed to initiate as sperm escape from epithelial and ciliary bindings formed within the isthmic regions of the female oviducts, leading to a conjecture in the literature that this waveform is mechanically important for sperm escape. Hence, we explore the mechanical effects of hyperactivation on a tethered sperm, focussing on a Newtonian fluid. Using a resistive force theory model we demonstrate that hyperactivation can indeed generate forces that pull the sperm away from a tethering point and consequently a hyperactivated sperm cell bound to an epithelial surface need not always be pushed by its flagellum. More generally, directions of the forces generated by tethered flagella are insensitive to reductions in beat frequency and the detailed flagellar responses depend on the nature of the binding at the tethering point. Furthermore, waveform asymmetry and amplitude increases enhance the tendency for a tethered flagellum to start tugging on its binding. The same is generally predicted to be true for reductions in the wavenumber of the flagellum beat, but not universally so, emphasising the dynamical complexity of flagellar force generation. Finally, qualitative observations drawn from experimental data of human sperm bound to excised female reproductive tract are also presented and are found to be consistent with the theoretical predictions. © 2012 Elsevier Ltd.

  14. In vitro immunomodulatory effects of microencapsulated umbilical cord Wharton jelly-derived mesenchymal stem cells in primary Sjögren's syndrome.

    Science.gov (United States)

    Alunno, Alessia; Montanucci, Pia; Bistoni, Onelia; Basta, Giuseppe; Caterbi, Sara; Pescara, Teresa; Pennoni, Ilaria; Bini, Vittorio; Bartoloni, Elena; Gerli, Roberto; Calafiore, Riccardo

    2015-01-01

    Human umbilical cord Wharton jelly-derived mesenchymal stem cells (hUCMS) are easy to retrieve in bulk. They may interact with immune cells by either cell contact or soluble factors. Little evidence is currently available on potential therapeutic application of hUCMS to systemic autoimmune disorders such as primary SS (pSS). We have recently developed an endotoxin-free alginate gel that can be used to microencapsulate different cell types for graft into non-immunosuppressed hosts. We aimed to assess the in vitro effects of IFN-γ-pretreated microencapsulated (CpS)-hUCMS on T cells of pSS. Ten pSS patients and 10 healthy donors were selected. Peripheral blood mononuclear cells (PBMCs) were obtained from venous blood to establish co-cultures with CpS-hUCMS. Lymphocyte proliferation and phenotypic analysis was performed by flow cytometry and real-time PCR on IFN-γ-pretreated hUCMS was performed before PBMCs co-culture. We found that CpS-hUCMS suppress pSS T cell proliferation and restore the Treg/Th17 ratio, thereby possibly positively impacting the pSS disease process. We have developed a new biohybrid drug delivery system that now waits for clinical application in autoimmune diseases, including pSS. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Pediatric SCI Rehabilitation Sara Klaas, MSW Transitions for Children with Spinal Cord Injury Patricia Mucia, RN Family Life After Pediatric Spinal Injury Dawn Sheaffer, MSW ...

  16. Double-level Incomplete Spinal Cord Injuries: A case report

    Directory of Open Access Journals (Sweden)

    Saeed Bin Ayaz

    2014-04-01

    Full Text Available Brown-Séquard Syndrome is a type of Incomplete Spinal Cord Injury characterized by a relatively greater ipsilateral loss of proprioception and motor function, with contralateral loss of pain and temperature sensations. The residual deficits in balance produced by such injury may render a person liable to fall that may result in vertebral fracture and another injury to the spinal cord. We present here a case who initially had Brown-Séquard Syndrome due to penetrating knife injury to the neck and later on developed Cauda Equina Syndrome (another Incomplete Spinal Cord Injury due to fractured LV1 following a fall. The fracture was fixed through Pedicle Screws and the patient underwent effective rehabilitation to gain maximum achievable independence in functional activities. [Cukurova Med J 2014; 39(2.000: 392-398

  17. An algorithmic programming approach for back pain symptoms in failed back surgery syndrome using spinal cord stimulation with a multicolumn surgically implanted epidural lead: a multicenter international prospective study.

    Science.gov (United States)

    Rigoard, Philippe; Jacques, Line; Delmotte, Alexandre; Poon, Katherine; Munson, Russell; Monlezun, Olivier; Roulaud, Manuel; Prevost, Audrey; Guetarni, Farid; Bataille, Benoit; Kumar, Krishna

    2015-03-01

    Many studies have demonstrated the efficacy and the medical/economic value of epidural spinal cord stimulation for the treatment of "failed back surgery syndrome" (FBSS). However, the back pain component of FBSS has been recalcitrant. Recent clinical trials have suggested that multicolumn surgically implanted leads combined with enhanced programming capabilities in the newer implantable pulse generators demonstrate the ability to treat the back pain component of FBSS. The objective of our present international multicentre study is to prospectively evaluate these findings in a larger population. We conducted a prospective, nonrandomized, observational study on 76 patients with refractory FBSS, consecutively implanted with multicolumn spinal cord stimulation (SCS) between 2008 and 2011 in three neurosurgical pain management centers (Poitiers, France; Montréal, Canada; and Regina, Canada). The primary objective of this study was to prospectively analyze the effect of multicolumn lead programming on paresthesia coverage for the back pain region in these patients. The secondary objective was to assess the analgesic efficacy of this technique on the global and back pain components. Paresthesia could be induced in the lower extremities in the majority of patients with at least one of the configurations tested. Bilateral low back paresthesia was induced in 53.5% of patients, while unilateral low back paresthesia was induced in 78.9% of patients. Multicolumn configurations were statistically more effective than monocolumn configurations for all anatomic regions studied. At 6 months, 75.4% of patients receiving multicolumn stimulation (n = 57) obtained at least a 30% improvement of the back pain VAS score, while 42.1% of patients obtained at least a 50% improvement of the back pain VAS score. This study confirms the hypothesis that multicolumn SCS should be considered as an important tool in the treatment of radicular and axial pain in FBSS patients. The efficacy of this

  18. Tether-mission design for multiple flybys of moon Europa

    Science.gov (United States)

    Sanmartin, J. R. S.; Charro, M. C.; Sanchez-Arriaga, G. S. A.; Sanchez-Torres, A. S. T.

    2015-10-01

    A tether mission to carry out multiple flybys of Jovian moon Europa is here presented. There is general agreement on elliptic-orbit flybys of Europa resulting in cost to attain given scientific goals lower than if actually orbiting the moon, tethers being naturally fit to fly-by rather than orbit moons1. The present mission is similar in this respect to the Clipper mission considered by NASA, the basic difference lying in location of periapsis, due to different emphasis on mission-challenge metrics. Clipper minimizes damaging radiation-dose by avoiding the Jupiter neighborhood and its very harsh environment; periapsis would be at Europa, apoapsis as far as moon Callisto. As in all past outer-planet missions, Clipper faces, however, critical power and propulsion needs. On the other hand, tethers can provide both propulsion and power, but must reach near the planet to find high plasma density and magnetic field values, leading to high induced tether current, and Lorentz drag and power. The bottom line is a strong radiation dose under the very intense Radiation Belts of Jupiter. Mission design focuses on limiting dose. Perijove would be near Jupiter, at about 1.2-1.3 Jovian radius, apojove about moon Ganymede, corresponding to 1:1 resonance with Europa, so as to keep dose down: setting apojove at Europa, for convenient parallel flybys, would require two perijove passes per flyby (the Ganymede apojove, resulting in high eccentricity, about 0.86, is also less requiring on tether operations). Mission is designed to attain reductions in eccentricity per perijove pass as high as Δe ≈ - 0.04. Due the low gravity-gradient, tether spinning is necessary to keep it straight, plasma contactors placed at both ends taking active turns at being cathodic. Efficiency of capture of the incoming S/C by the tether is gauged by the ratio of S/C mass to tether mass; efficiency is higher for higher tape-tether length and lower thickness and perijove. Low tether bowing due to the Lorentz

  19. Spinal Cord Injury without Radiological Abnormality in an 8 Months Old Female Child: A Case Report

    OpenAIRE

    Bansal, Kunal R.; Chandanwale, Ajay S

    2016-01-01

    Introduction: Spinal cord injury in children frequently occurs without fracture or dislocation. SCIWORA is a syndrome occurring when the spinal cord sustains neural damage during a traumatic event without positive radiographic findings. The incidence of SCIWORA was found to be 8% to 32% in various studies with very few cases documented in children below the age of 1 year. We report such a case of spinal cord injury without radiological abnormality in an 8 months old female child. Case Report:...

  20. Tether pointing platform and space elevator mechanisms analysis of the key concepts for SATP and scaled SATP

    Science.gov (United States)

    Turci, E.

    1986-01-01

    The key concepts for a scaled and full model Science and Applications Tethered Platform (SATP) are analysized. This includes a tether pointing platform and a space elevator. The mechanism concepts and technological solutions are given. The idea of the tether pointing platform mechanism is to control and stabilize the attitude of a platform by means of a movable tether. The idea of the space elevator mechanism for a scaled SATP is to drag the tether gripping it between two rotating wheels.

  1. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Spinal Cord Injury 101 Lawrence Vogel, MD The Basics of Pediatric SCI Rehabilitation Sara Klaas, MSW Transitions ... PhD Michelle Meade, PhD Jonathon Rose, PhD The Basics of Spinal Cord Injury Rehabilitation Kristine Cichowski, MS ...

  2. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... in a Wheelchair Lisa Rosen, MS Spasticity, Physical Therapy-Lokomat T. George Hornby, PhD, PT Empowering the Patient After Spinal Cord Injury Guy W. Fried, MD Substance Abuse and Spinal Cord Injury Allen Heinemann, PhD How ...

  3. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Read Bio Medical Director, Spinal Cord Injury Rehabilitation Program, Rehabilitation Institute of Chicago play_arrow What is ... What is the “Spinal Cord Injury Model Systems” program? play_arrow What are the most promising new ...

  4. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Blog Videos By Topic Media Resources Donate to support families facing spinal cord injuries Peer Counseling 312-284- ... of Use FacingDisability.com is an informational and support website for families facing spinal cord injuries. The website does not ...

  5. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... MS Spasticity, Physical Therapy-Lokomat T. George Hornby, PhD, PT Empowering the Patient After Spinal Cord Injury ... Substance Abuse and Spinal Cord Injury Allen Heinemann, PhD How Peer Counseling Works Julie Gassaway, MS, RN ...

  6. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... play_arrow What is the “Spinal Cord Injury Model Systems” program? play_arrow What are the most promising new treatments for spinal cord injuries? play_arrow What are the latest developments in the use of electrical stimulation for spinal ...

  7. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Life in a Wheelchair Lisa Rosen, MS Spasticity, Physical Therapy-Lokomat T. George Hornby, PhD, PT Empowering the Patient After Spinal Cord Injury Guy W. Fried, MD Substance Abuse and Spinal Cord Injury Allen Heinemann, PhD How ...

  8. Tethered elevator: A unique opportunity for space processing

    Science.gov (United States)

    Monti, R.

    1986-01-01

    The latest fluid dynamic and material science experiments in the microgravity environment have emphasized the importance of the residual gravity level and of the g-jitter on fluid physics phenomena. The tethered elevator presents the possibility of providing variable g-levels (both steady and g-jitter) around a very low steady g-level (that can be realized when the elevator is near the center of mass of the space station-tether complex). When positioning a variable periodic oscillation to the payload a clean g-jitter disturbance can be obtained that would not be otherwise obtainable by other systems. These two possibilities make the elevator a facility to help resolve a number of still open questions that are preventing wider utilization of the space environment in the microgravity area.

  9. Tethered naphthalene diimide intercalators enhance DNA triplex stability.

    Science.gov (United States)

    Gianolio, D A; McLaughlin, L W

    2001-09-01

    Naphthalene diimides function as effective intercalators and when tethered to the 5'-terminus of a pyrimidine-rich oligonucleotide can contribute significantly to the overall stabilization of DNA triplexes. This stabilization can be further enhanced by alterations to the linker tethering the DNA sequence and the intercalator. Less flexible linkers, and particularly one with a phenyl ring present, appear to permit the stabilization afforded by the bound intercalator to be transferred more effectively to the three-stranded complex. The conjugate containing the phenyl linker exhibits a T(M) value that is increased by 28 degrees C relative to the unconjugated triplex. That the linker itself contributes to the observed stabilization is clear since introduction of the phenyl linker increases the observed T(M) by 11 degrees C relative to a simple flexible linker.

  10. Synthesis and insertion chemistry of mixed tether uranium metallocene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Siladke, Nathan A.; LeDuc, Jennifer; Ziller, Joseph W.; Evans, William J. [Department of Chemistry, University of California, Irvine, CA (United States)

    2012-11-12

    The synthesis of mixed tethered alkyl uranium metallocenes has been investigated by examining the reactivity of the bis(tethered alkyl) metallocene [(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}CH{sub 2}-κC){sub 2}U] (1) with substrates that react with only one of the U-C linkages. The effect of these mixed tether coordination environments on the reactivity of the remaining U-C bond has been studied by using CO insertion chemistry. One equivalent of azidoadamantane (AdN{sub 3}) reacts with 1 to yield the mixed tethered alkyl triazenido complex [(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}CH{sub 2}-κC)U(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}-CH{sub 2}NNN-Ad-κ{sup 2}N{sup 1,3})]. Similarly, a single equivalent of CS{sub 2} reacts with 1 to form the mixed tethered alkyl dithiocarboxylate complex [(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}CH{sub 2}-κC)U(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}- CH{sub 2}C(S){sub 2}-κ{sup 2}S,S{sup '})], a reaction that constitutes the first example of CS{sub 2} insertion into a U{sup 4+}-C bond. Complex 1 reacts with one equivalent of pyridine N-oxide by C-H bond activation of the pyridine ring to form a mixed tethered alkyl cyclometalated pyridine N-oxide complex [(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}CH{sub 2}-κC)(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 3})U(C{sub 6}H{sub 4}NO-κ{sup 2} C,O)]. The remaining (η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}CH{sub 2}-κC){sup 2-} ligand in each of these mixed tethered species show reactivity towards CO and tethered enolate ligands form by insertion. Subsequent rearrangement have been identified in [(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 3})U(C{sub 5}H{sub 4}NO-κ{sup 2}C,O)(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}C(=CH{sub 2})O- κO)] and [(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}CH{sub 2}NNN-Ad-κ{sup 2}N{sup 1,3})U(η{sup 5}-C{sub 5}Me{sub 4}SiMe{sub 2}C(=CH{sub 2})O-κO)]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. The tethered satellite system for low density aerothermodynamics studies

    Science.gov (United States)

    Carlomagno, Giovanni M.; De Luca, Luigi; Siemers, P. M., III; Wood, George M., Jr.

    1986-01-01

    The feasibility of the operation of the Tethered Satellite System (TSS) as a continuous open wind tunnel for low-density aerothermodynamic studies (applicable to the design of hypersonic space vehicles including STARFAC, AOTV, and ERV) is considered. The Shuttle Continuous Open Wind Tunnel (SCOWT) program, for the study of the energy and momentum transfer between the tethered satellite and its environmental medium during the TSS/2 mission, is described. Instrumentation and TSS design requirements to meet SCOWT objectives are also considered. SCOWT will provide information on the gasdynamic processes occurring downstream of the bow wave standing in front of the TS, the chemistry and physics of the upper atmosphere related to satellite aerothermodynamics, and TSS's overall experimental envelope of operation.

  12. Asteroid rotation control via a tethered solar sail

    Science.gov (United States)

    Gao, Youtao; Wu, Jingyun

    2016-12-01

    The rotation of asteroids causes difficulties in the exploration of asteroids or prevention of asteroids impact on the Earth. We propose to use a solar sail to control, i.e., slow down or stop the rotational motion of an asteroid. First, the dynamic model of a tethered solar sail in the rotating gravitational field of an asteroid is presented. An optimal control method is employed to determine the control law of the tethered solar sail. The optimal control problem is converted into a nonlinear programming problem with the Gauss pseudospectral method. Simulation results show that this method can effectively slow down or even stop the rotation of an asteroid. A solar sail of 105 m2 can stop the rotation of the asteroid Apophis in 1000 days.

  13. Split Cord Malformations

    Directory of Open Access Journals (Sweden)

    Yurdal Gezercan

    2015-06-01

    Full Text Available Split cord malformations are rare form of occult spinal dysraphism in children. Split cord malformations are characterized by septum that cleaves the spinal canal in sagittal plane within the single or duplicated thecal sac. Although their precise incidence is unknown, split cord malformations are exceedingly rare and represent %3.8-5 of all congenital spinal anomalies. Characteristic neurological, urological, orthopedic clinical manifestations are variable and asymptomatic course is possible. Earlier diagnosis and surgical intervention for split cord malformations is associated with better long-term fuctional outcome. For this reason, diagnostic imaging is indicated for children with associated cutaneous and orthopedic signs. Additional congenital anomalies usually to accompany the split cord malformations. Earlier diagnosis, meticuolus surgical therapy and interdisciplinary careful evaluation and follow-up should be made for good prognosis. [Cukurova Med J 2015; 40(2.000: 199-207

  14. Currents between tethered electrodes in a magnetized laboratory plasma

    Science.gov (United States)

    Stenzel, R. L.; Urrutia, J. M.

    1989-01-01

    Laboratory experiments on important plasma physics issues of electrodynamic tethers were performed. These included current propagation, formation of wave wings, limits of current collection, nonlinear effects and instabilities, charging phenomena, and characteristics of transmission lines in plasmas. The experiments were conducted in a large afterglow plasma. The current system was established with a small electron-emitting hot cathode tethered to an electron-collecting anode, both movable across the magnetic field and energized by potential difference up to V approx.=100 T(sub e). The total current density in space and time was obtained from complete measurements of the perturbed magnetic field. The fast spacecraft motion was reproduced in the laboratory by moving the tethered electrodes in small increments, applying delayed current pulses, and reconstructing the net field by a linear superposition of locally emitted wavelets. With this technique, the small-amplitude dc current pattern is shown to form whistler wings at each electrode instead of the generally accepted Alfven wings. For the beam electrode, the whistler wing separates from the field-aligned beam which carries no net current. Large amplitude return currents to a stationary anode generate current-driven microinstabilities, parallel electric fields, ion depletions, current disruptions and time-varying electrode charging. At appropriately high potentials and neutral densities, excess neutrals are ionized near the anode. The anode sheath emits high-frequency electron transit-time oscillations at the sheath-plasma resonance. The beam generates Langmuir turbulence, ion sound turbulence, electron heating, space charge fields, and Hall currents. An insulated, perfectly conducting transmission line embedded in the plasma becomes lossy due to excitation of whistler waves and magnetic field diffusion effects. The implications of the laboratory observations on electrodynamic tethers in space are discussed.

  15. Crowded, Confined, and Frustrated: Dynamics of Molecules Tethered to Nanoparticles

    KAUST Repository

    Agarwal, Praveen

    2012-12-01

    Above a critical chemistry-dependent molecular weight, all polymer molecules entangle and, as a result, exhibit slow dynamics, enhanced viscosity, and elasticity. Herein we report on the dynamics of low molecular weight polymers tethered to nanoparticles and find that even conventionally unentangled chains manifest dynamical features similar to entangled, long-chain molecules. Our findings are shown to imply that crowding and confinement of polymers on particles produce topological constraints analogous to those in entangled systems. © 2012 American Physical Society.

  16. Deorbit efficiency assessment through numerical simulation of electromagnetic tether devices

    Directory of Open Access Journals (Sweden)

    Alexandru IONEL

    2016-03-01

    Full Text Available This paper examines the deorbit efficiency of an electromagnetic tether deorbit device when used to deorbit an upper stage at end of mission from low Earth orbit. This is done via a numerical simulation in Matlab R2013a, using ode45, taking into account perturbations on the upper stage’s trajectory. The perturbations taken into account are the atmospheric drag, the 3rd body (Sun and Moon, and Earth’s gravitational potential expanded into spherical harmonics.

  17. Looking at the end of the ROV tether

    Energy Technology Data Exchange (ETDEWEB)

    Grange, P.

    1983-06-01

    It is expected that eventually the remotely operated vehicle (ROV) will discard its clumsy, expensive, and restrictive umbilical, but for the moment virtually all these vehicles remain tethered to their mother service vessels. Lack of power has been the persistent problem with these vehicles but this could be effectively overcome with the development of closed loop internal combustion engines. The development of these engines for integration into ROV's is discussed.

  18. Cracking pressure control of parylene checkvalve using slanted tensile tethers

    OpenAIRE

    Lin, Jeffrey Chun-Hui; Yu, Feiqiao; Tai, Yu-Chong

    2010-01-01

    MEMS check valves with fixed cracking pressures are important in micro-fluidic applications where the pressure, flow directions and flow rates all need to be carefully controlled. This work presents a new surface-micromachined parylene check valve that uses residual thermal stress in the parylene to control its cracking pressure. The new check valve uses slanted tethers to allow the parylene tensile stress to apply a net downward force on the valving seat against the orifice. The angle of the...

  19. Shuttle Tethered Aerothermodynamics Research Facilty (STARFAC) instrumentation requirements

    Science.gov (United States)

    Wood, G. M.; Siemers, P. M.; Carlomagno, G. M.; Hoffman, J.

    1986-01-01

    The instrumentation requirements for the Shuttle Tethered Aerothermodynamic Research Facility (STARFAC) are presented. The typical physical properties of the terrestrial atmosphere are given along with representative atmospheric daytime ion concentrations and the equilibrium and nonequilibrium gas property comparison from a point away from a wall. STARFAC science and engineering measurements are given as are the TSS free stream gas analysis. The potential nonintrusive measurement techniques for hypersonic boundary layer research are outlined along with the quantitative physical measurement methods for aerothermodynamic studies.

  20. Downward-deployed tethered platforms for high enthalpy aerothermodynamic research

    Science.gov (United States)

    Wood, George M.; Siemers, Paul M.; Squires, R. Kenneth; Wolf, Henry; Carlomagno, Giovanni M.

    1988-01-01

    The data on aerothermodynamic and aerodynamic interactions at altitudes above 50 km is extremely limited because of the relative inaccessibility of the region to research vehicles of any sort. This paper addresses the practicability of using downward deployed satellites tethered to an orbiting host vehicle in order to obtain steady-state data in the upper reaches of the region above 80 or 90 km.

  1. Current challenges in spinal cord stimulation.

    Science.gov (United States)

    Kumar, Krishna; Caraway, David L; Rizvi, Syed; Bishop, Sharon

    2014-06-01

    This study aims to review the current state of spinal cord stimulation for the treatment of chronic pain associated with failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) and to describe intraspinal targets and stimulation parameters, patient selection, therapy cost-effectiveness, and strategies to improve outcomes. We drew on professional literature spanning four decades, our work with national and international professional societies, and our own extensive clinical experience to summarize contemporary knowledge of the safety, efficacy, cost-efficiency, and challenges associated with spinal cord stimulation in treating chronic pain. The safety, efficacy, and cost-efficiency of spinal cord stimulation in treating chronic pain associated with FBSS and CRPS are well established through randomized controlled trials and long-term observational studies. Challenges include reducing wait-times before implant, which are associated with lower success rates; increasing awareness of this therapy among referring physicians, patients, and payers; decreasing device-related complications by incorporating advanced technology, improved operative and trialing techniques, and appropriate patient selection; and capturing functional and quality-of-life outcomes. Spinal cord stimulation must be part of an overall treatment plan to manage chronic pain, and must engage physicians, patients, their families, pharmacists, nursing staff, and mental health experts in supporting a return to employment, if possible, and to a full domestic and social life. Innovation in spinal cord stimulation therapy has intensified with numerous new technical capabilities, safety advances, and novel stimulation targets. This progress holds hope for the many sufferers of chronic pain. © 2014 International Neuromodulation Society.

  2. Evaluation of the Effectiveness of Percutaneous Octapolar Leads in Pain Treatment with Spinal Cord Stimulation of Patients with Failed Back Surgery Syndrome During a 1-Year Follow-Up: A Prospective Multicenter International Study.

    Science.gov (United States)

    Gatzinsky, Kliment; Baardsen, Roald; Buschman, Hendrik P

    2017-04-01

    To evaluate the effectiveness and safety of percutaneous octapolar (8-contact) leads in spinal cord stimulation (SCS) treatment of failed back surgery syndrome (FBSS) patients who have not reached their therapy goals with other treatment interventions. Our prospective, multicenter, open-label, nonrandomized study included 93 patients ≥ 18 years of age suffering from chronic (≥ 6 months), intractable pain predominantly in the legs. Patients implanted with octapolar lead(s) and a neurostimulator after a successful test trial were followed for 12 months. Patients provided self-reported data on change in visual analog scale (VAS) score for leg pain (primary outcome) and low back pain, quality of life (EuroQol 5 dimensions [EQ-5D] index), sleep, medication use, and paresthesia coverage (secondary outcomes). Adverse events and preferred stimulation settings were documented. Eighty-one (87%) patients had a successful SCS trial. Patients reported significantly improved leg pain relief; average VAS score was 72 ± 17 prior to SCS treatment and 32 ± 24 at 12 months (P patients were responders (≥ 50% pain reduction) on leg and back pain, respectively, after 12 months. A decrease in medication use was seen for antidepressants and anticonvulsants. Eighty-eight percent of the patients managed with 1 or 2 programs for optimal effect and paresthesia coverage. Twenty-five SCS-related adverse events were registered in 22 patients (24%). Surgical revision due to lead displacement or dysfunction was needed in 6 (6%) of the patients. Use of percutaneous octapolar SCS leads gives significant long-term pain relief and improvement in quality of life and sleep in FBSS patients. The outcomes are better than reported on 4-contact leads and indicate that the progress in SCS technology that has taken place during the past decade correlates with therapy improvements. © 2016 World Institute of Pain.

  3. Review of the ProSEDS Electrodynamic Tether Mission Development

    Science.gov (United States)

    Vaughn, Jason A.; Curtis, Leslie; Gilchrist, Brian E.; Bilen, Sven; Lorenzini, Enrico

    2004-01-01

    The Propulsive Small Expendable Deployer System (ProSEDS) space experiment was ready to fly as a secondary payload on a Delta-II expendable launch vehicle in late March 2003. Concerns raised in February 2003 by the International Space Station resulted in the delay of the launch of ProSEDS. Issues associated with the delayed launch date and a change in starting altitude resulted in the cancellation of the mission. ProSEDS was intended to deploy a tether (5 km bare wire plus 10 km non-conducting Dyneema) from a Delta I1 second stage to achieve adequate drag thrust that would lower the orbit of the system over days as opposed to months due to atmospheric drag. It was also designed to utilize the tether-generated current to provide limited spacecraft power. Considerable effort and testing went in to developing the ProSEDS system by a dedicated team. Through this effort, important technological issues were identified and addressed and this presentation will discuss some of the important technical issues and hurdles that had to be addressed to successfully prepare for flight. It is intended that this information will be of use for future tether mission and experiment designers.

  4. A Tether-Based Variable-Gravity Research Facility Concept

    Science.gov (United States)

    Sorensen, Kirk

    2006-01-01

    The recent announcement of a return to the Moon and a mission to Mars has made the question of human response to lower levels of gravity more important. Recent advances in tether technology spurred by NASA s research in MXER tethers has led to a re-examination of the concept of a variable-gravity research facility (xGRF) for human research in low Earth orbit. Breakthroughs in simplified inertial tracking have made it possible to consider eliminating the despun section of previous designs. This, in turn, improves the prospect of a facility based entirely around a tether, with the human module on one end and a countermass on the other. With such a configuration, propellantless spinup and spindown is also possible based on the conservation of angular momentum from a gravity-gradient configuration to a spinning configuration. This not only saves large amounts of propellant but vastly simplifies crew and consumable resupply operations, since these can now be done in a microgravity configuration. The importance of the science to be obtained and the performance improvements in this new design argue strongly for further investigation.

  5. Position Control of an X4-Flyer Using a Tether

    Directory of Open Access Journals (Sweden)

    Yusuke Ouchi

    2016-05-01

    Full Text Available In Japan, aging of infrastructures, such as roads,bridges, and water and sewer services, etc. poses a problem, andit is required to extend the life-span of such infrastructures bymaintenance. Among infrastructures, especially bridges areperiodically inspected by short range visual observations, whichcheck the damage and deterioration of the surface. However,since there are some cases where the short range visualobservation is difficult, an alternative method is required so as toreplace the short range visual observation with it. So, "X4-Flyer"is very attractive because of realizing a movement at high altitudeeasily. The objective of this study is to develop a tethered X4-Flyer, so that the conventional short range visual observation ofbridges is replaced by it. In this paper, a method for themeasurement and control of the position is described by using atether for controlling the position of the X4-Flyer. In addition, itis checked whether the tethered X4-Flyer can control the positionusing the proposed method or not, letting it fly in a state in whicha tether is being attached

  6. Artificial auroral effects from a bare conducting tether

    Science.gov (United States)

    Martínez-Sanchez, M.; Sanmartín, J. R.

    1997-12-01

    An electrically floating metallic bare tether in a low Earth orbit would be highly negative with respect to the ambient plasma over most of its length, and would be bombarded by ambient ions. This would liberate secondary electrons, which, after acceleration through the same voltage, would form a magnetically guided two-sided planar e beam, and result in auroral effects (ionization and light emission) upon impact on the atmospheric E layer, at about 120-140 km altitude. This paper examines in a preliminary way the feasibility of using this effect as an upper atmospheric probe. Ionization rates can reach up to 105cm-3s-1 if a tape, instead of a wire, is used as tether. Contrary to standard e beams, the beam from the tether is free of spacecraft charging and plasma interaction problems, and its energy flux varies across the cross section, which is quite large; this would make possible continuous observation from the satellite, with high resolution, both spectral and vertical, of the induced optical emissions. Ground observation might be possible at latitudes around 40°, for night, magnetically quiet conditions.

  7. Investigation of force approximations in tethered cells simulations

    CERN Document Server

    Zakrisson, Johan; Axner, Ove; Andersson, Magnus

    2015-01-01

    Simulations of tethered cells in viscous sub-layers are frequently performed using the Stokes drag force, but without taking into account contributions from surface corrections, lift forces, buoyancy, the Basset force, the cells finite inertia, or added mass. In this work, we investigate to which extent such contributions influence, under a variety of hydrodynamic conditions, the force at the anchor point of a tethered cell and the survival probability of a bacterium that is attached to a host by either a slip or a catch bond via a tether with a few different biomechanical properties. We show that a consequence of not including some of these contributions is that the force to which a bond is exposed can be significantly underestimated; in general by ~32-46 %, where the influence of the surface corrections dominate (the parallel and normal correction coefficients contribute with ~5-8 or 23-26 %, respectively). The Basset force is a major contributor, up to 20 %, for larger cells and shear rates. The lift force...

  8. A Method to Predict the Orbital Lifetimes of Free Tethers and Tether-Trailing Satellites using Artificial Neural Networks

    Science.gov (United States)

    1992-08-28

    done by Freud .’ Prior to his psychoanalysis investigations, Freud attempted to ".... represent psychical processes as quantitatively determinate states...parent vehicle for (1) tether initiated reentry or orbit transfer of a subsatellite, and/or (2) local area operations requiring return to the space...performing flow analyses routinely use empirically- derived expressions to calculate convection heat transfer coefficients.ś Another example occurs in

  9. Modeling spinal cord biomechanics

    Science.gov (United States)

    Luna, Carlos; Shah, Sameer; Cohen, Avis; Aranda-Espinoza, Helim

    2012-02-01

    Regeneration after spinal cord injury is a serious health issue and there is no treatment for ailing patients. To understand regeneration of the spinal cord we used a system where regeneration occurs naturally, such as the lamprey. In this work, we analyzed the stress response of the spinal cord to tensile loading and obtained the mechanical properties of the cord both in vitro and in vivo. Physiological measurements showed that the spinal cord is pre-stressed to a strain of 10%, and during sinusoidal swimming, there is a local strain of 5% concentrated evenly at the mid-body and caudal sections. We found that the mechanical properties are homogeneous along the body and independent of the meninges. The mechanical behavior of the spinal cord can be characterized by a non-linear viscoelastic model, described by a modulus of 20 KPa for strains up to 15% and a modulus of 0.5 MPa for strains above 15%, in agreement with experimental data. However, this model does not offer a full understanding of the behavior of the spinal cord fibers. Using polymer physics we developed a model that relates the stress response as a function of the number of fibers.

  10. Dynamic analysis of the tether transportation system using absolute nodal coordinate formulation

    Science.gov (United States)

    Sun, Xin; Xu, Ming; Zhong, Rui

    2017-10-01

    Long space tethers are becoming a rising concern as an alternate way for transportation in space. It benefits from fuel economizing. This paper focuses on the dynamics of the tether transportation system, which consists of two end satellites connected by a flexible tether, and a movable vehicle driven by the actuator carried by itself. The Absolute Nodal Coordinate Formulation is applied to the establishment of the equation of motion, so that the influence caused by the distributed mass and elasticity of the tether is introduced. Moreover, an approximated method for accelerating the calculation of the generalized gravitational forces on the tether is proposed by substituting the volume integral every step into summation of finite terms. Afterwards, dynamic evolutions of such a system in different configurations are illustrated using numerical simulations. The deflection of the tether and the trajectory of the crawler during the transportation is investigated. Finally, the effect on the orbit of the system due to the crawler is revealed.

  11. Trauma: Spinal Cord Injury.

    Science.gov (United States)

    Eckert, Matthew J; Martin, Matthew J

    2017-10-01

    Injuries to the spinal column and spinal cord frequently occur after high-energy mechanisms of injury, or with lower-energy mechanisms, in select patient populations like the elderly. A focused yet complete neurologic examination during the initial evaluation will guide subsequent diagnostic procedures and early supportive measures to help prevent further injury. For patients with injury to bone and/or ligaments, the initial focus should be spinal immobilization and prevention of inducing injury to the spinal cord. Spinal cord injury is associated with numerous life-threatening complications during the acute and long-term phases of care that all acute care surgeons must recognize. Published by Elsevier Inc.

  12. New surgical approach for late complications from spinal cord injury

    Directory of Open Access Journals (Sweden)

    Reis Antonio J

    2006-10-01

    Full Text Available Abstract Background The most frequent late complications in spinal cord injury result from arachnoiditis and consequent alterations in dynamics of cerebrospinal fluid flow. A surgical procedure carried out on patients with these alterations, resolved the various pathologies more efficiently in all cases. Methods From October 2000 to March 2006, 23 patients were selected for surgery: three showed signs of syringomyelia, three presented with microcystic lesions, three presented with arachnoid cysts in different locations but always confluent to the scar area, and 14 showed evidence of tethered cords. The surgery consisted of laminectomy at four levels, followed by dural opening in order to remove all the arachnoiditis at the level of the scar and to remove the altered arachnoid and its cysts, at least at two levels above and below the lesion. The dentate ligaments were cut at all exposed levels. Results The patients had no postoperative problems and not only retained all neurological functions but also showed neurological recovery. According to the motor and sensory scale of the American Spinal Injury Association, the recoveries were motor 20.6% (P Conclusion This alternative surgery resolved the pathologies provoking neurological deterioration by releasing the complete spinal cord at the level of the scar and the levels above and below it. It thus avoids myelotomies and the use of shunts and stents, which have a high long-term failure rate and consequent relapses. Nevertheless, this surgical procedure allows patients the chance to opt for any further treatment that may evolve in the future.

  13. Vocal cord palsy: An uncommon presenting feature of myasthenia gravis

    Directory of Open Access Journals (Sweden)

    Sethi Prahlad

    2011-01-01

    Full Text Available Vocal cord palsy can have myriad causes. Unilateral vocal cord palsy is common and frequently asymptomatic. Trauma, head, neck and mediastinal tumors as well as cerebrovascular accidents have been implicated in causing unilateral vocal cord palsy. Viral neuronitis accounts for most idiopathic cases. Bilateral vocal cord palsy, on the other hand, is much less common and is a potentially life-threatening condition. Myasthenia gravis, an autoimmune disorder caused by antibodies targeting the post-synaptic acetylcholine receptor, has been infrequently implicated in its causation. We report here a case of bilateral vocal cord palsy developing in a 68-year-old man with no prior history of myasthenia gravis 2 months after he was operated on for diverticulitis of the large intestine. Delay in considering the diagnosis led to endotracheal intubation and prolonged mechanical ventilation with attendant complications. Our case adds to the existing literature implicating myasthenia gravis as an infrequent cause of bilateral vocal cord palsy. Our case is unusual as, in our patient, acute-onset respiratory distress and stridor due to bilateral vocal cord palsy was the first manifestation of a myasthenic syndrome.

  14. Spinal cord compression in {beta}-thalassemia: follow-up after radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Silvana Fahel da; Figueiredo, Maria Stella; Cancado, Rodolfo Delfini; Nakadakare, Fernando; Segreto, Roberto; Kerbauy, Jose [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina

    1998-12-01

    Spinal cord compression due to extramedullary hematopoiesis is a well-described bu rare syndrome encountered in several hematologic disorders, including {beta}-thalassemia. We report a case of a patient with intermediate {beta}-thalassemia and crural paraparesis due to spinal cord compression by a paravertebral extramedullary mass. She was successfully treated with low-dose radiotherapy and transfusions. After splenectomy, she was regularly followed up for over four years without transfusion or recurrence of spinal cord compression. Extramedullary hematopoiesis should be investigated in patients with hematologic disorders and spinal cord symptoms. The rapid recognition and treatment with radiotherapy can dramatically alleviate symptoms. (author)

  15. Tethered elevator and platforms as space station facilities: Systems studies and demonstrative experiments

    Science.gov (United States)

    1986-01-01

    Several key concepts of the science and applications tethered platforms were studied. Some conclusions reached are herein listed. Tether elevator and platform could improve the space station scientific and applicative capabilities. The space elevator presents unique characteristics as microgravity facility and as a tethered platform servicing vehicle. Pointing platforms could represent a new kind of observation facility for large class of payloads. The dynamical, control and technological complexity of these concepts advised demonstrative experiments. The on-going tethered satellite system offers the opportunity to perform such experiments. And feasibility studies are in progress.

  16. Novel Roaming and Stationary Tethered Aerial Robots for Continuous Mobile Missions in Nuclear Power Plants

    Directory of Open Access Journals (Sweden)

    Beom W. Gu

    2016-08-01

    Full Text Available In this paper, new tethered aerial robots including roaming tethered aerial robots (RTARs for radioactive material sampling and stationary tethered aerial robots (STARs for environment monitoring are proposed to meet extremely-long-endurance missions of nuclear power plants. The flight of the proposed tethered aerial robots may last for a few days or even a few months as long as the tethered cable provides continuous power. A high voltage AC or DC power system was newly adopted to reduce the mass of the tethered cable. The RTAR uses a tethered cable spooled from the aerial robot and an aerial tension control system. The aerial tension control system provides the appropriate tension to the tethered cable, which is accordingly laid down on the ground as the RTAR roams. The STAR includes a tethered cable spooled from the ground and a ground tension control system, which enables the STAR to reach high altitudes. Prototypes of the RTAR and STAR were designed and successfully demonstrated in outdoor environments, where the load power, power type, operating frequency, and flight attitude of the RTAR and STAR were: 180 W, AC 100 kHz, and 20 m; and 300 W, AC or DC 100 kHz, and 80 m, respectively.

  17. Configuration maintaining control of three-body ring tethered system based on thrust compensation

    Science.gov (United States)

    Huang, Panfeng; Liu, Binbin; Zhang, Fan

    2016-06-01

    Space multi-tethered systems have shown broad prospects in remote observation missions. This paper mainly focuses on the dynamics and configuration maintaining control of space spinning three-body ring tethered system for such mission. Firstly, we establish the spinning dynamic model of the three-body ring tethered system considering the elasticity of the tether using Newton-Euler method, and then validate the suitability of this model by numerical simulation. Subsequently, LP (Likins-Pringle) initial equilibrium conditions for the tethered system are derived based on rigid body's equilibrium theory. Simulation results show that tether slack, snapping and interaction between the tethers exist in the three-body ring system, and its' configuration can not be maintained without control. Finally, a control strategy based on thrust compensation, namely thrust to simulate tether compression under LP initial equilibrium conditions is designed to solve the configuration maintaining control problem. Control effects are verified by numerical simulation compared with uncontrolled situation. Simulation results show that the configuration of the three-body ring tethered system could maintain under this active control strategy.

  18. Three-dimensional characterization of tethered microspheres by total internal reflection fluorescence microscopy

    Science.gov (United States)

    Blumberg, Seth; Gajraj, Arivalagan; Pennington, Matthew W.; Meiners, Jens-Christian

    2005-01-01

    Tethered particle microscopy is a powerful tool to study the dynamics of DNA molecules and DNA-protein complexes in single-molecule experiments. We demonstrate that stroboscopic total internal reflection microscopy can be used to characterize the three-dimensional spatiotemporal motion of DNA-tethered particles. By calculating characteristic measures such as symmetry and time constants of the motion, well-formed tethers can be distinguished from defective ones for which the motion is dominated by aberrant surface effects. This improves the reliability of measurements on tether dynamics. For instance, in observations of protein-mediated DNA looping, loop formation is distinguished from adsorption and other nonspecific events.

  19. Novel roaming and stationary tethered aerial robots for continuous mobile missions in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Beom W.; Choi, Su Y.; Rim, Chun T. [Dept. of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of); Choi, Young Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cai, Guowei; Seneviratne, Lakmal [Dept. of Aerospace Engineering, Khalifa University, Abu Dhabi (United Arab Emirates)

    2016-08-15

    In this paper, new tethered aerial robots including roaming tethered aerial robots (RTARs) for radioactive material sampling and stationary tethered aerial robots (STARs) for environment monitoring are proposed to meet extremely-long-endurance missions of nuclear power plants. The flight of the proposed tethered aerial robots may last for a few days or even a few months as long as the tethered cable provides continuous power. A high voltage AC or DC power system was newly adopted to reduce the mass of the tethered cable. The RTAR uses a tethered cable spooled from the aerial robot and an aerial tension control system. The aerial tension control system provides the appropriate tension to the tethered cable, which is accordingly laid down on the ground as the RTAR roams. The STAR includes a tethered cable spooled from the ground and a ground tension control system, which enables the STAR to reach high altitudes. Prototypes of the RTAR and STAR were designed and successfully demonstrated in outdoor environments, where the load power, power type, operating frequency, and flight attitude of the RTAR and STAR were: 180 W, AC 100 kHz, and 20 m; and 300 W, AC or DC 100 kHz, and 80 m, respectively.

  20. Spinal Cord Injury 101

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    Full Text Available ... with SCI Personal Experiences by Topic Resources Peer Counseling Blog About Media Donate close search Understanding Spinal ... with SCI Personal Experiences by Topic Resources Peer Counseling Blog About Media Donate Spinal Cord Injury Medical ...

  1. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Diane M. Rowles, MS, NP How Family Life Changes After Spinal Cord Injury Nancy Rosenberg, PsyD Understanding SCI Rehabilitation Donald Peck Leslie, MD Adjusting to Social Life in a Wheelchair Lisa Rosen, MS Spasticity, ...

  2. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... After Pediatric Spinal Injury Dawn Sheaffer, MSW Rehabilitation Psychological Realities after Spinal Cord Injury Toby Huston, PhD ... not provide medical advice, recommend or endorse health care products or services, or control the information found ...

  3. Spinal Cord Injury 101

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    Full Text Available ... With Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC Understanding Spinal Cord Injury About Us ... With Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC close close

  4. Spinal Cord Injury 101

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    Full Text Available ... Preventing Pressure Sores Mary Zeigler, MS Transition from Hospital to Home Kim Eberhardt Muir, MS Coping with ... Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC Understanding Spinal Cord Injury About Us Expert ...

  5. Spinal Cord Injury 101

    Science.gov (United States)

    ... Preventing Pressure Sores Mary Zeigler, MS Transition from Hospital to Home Kim Eberhardt Muir, MS Coping with ... Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC Understanding Spinal Cord Injury About Us Expert ...

  6. Spinal Cord Injury 101

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    Full Text Available ... to experience neuropathic pain after a spinal cord injury? play_arrow What is a “physiatrist”? play_arrow What factors are important in choosing a rehabilitation facility after ...

  7. Spinal Cord Injury 101

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    Full Text Available ... Living with SCI Personal Experiences by Topic Resources Peer ... Adult Injuries Spinal Cord Injury 101 David Chen, MD Preventing Pressure Sores Mary Zeigler, MS Transition from Hospital to ...

  8. Spinal Cord Injury 101

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    Full Text Available ... com is an informational and support website for families facing spinal cord injuries. The website does not provide medical advice, recommend or endorse health care products or services, or control the information ...

  9. Spinal Cord Injury 101

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    Full Text Available ... OT Anne Bryden, OT The Role of the Social Worker after Spinal Cord Injury Patti Rogers, SW Marguerite ... play_arrow What are the latest developments in the use of electrical stimulation for spinal ...

  10. Cord-Blood Banking

    Science.gov (United States)

    ... cord blood mainly because of the promise that stem cell research holds for the future. Most of us would have little use for stem cells now, but research into using them to treat diseases is ongoing — ...

  11. Spinal Cord Injury 101

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    Full Text Available ... arrow What is the “Spinal Cord Injury Model Systems” program? play_arrow What are the most promising ... health care products or services, or control the information found on external websites. The Hill Foundation is ...

  12. Spinal Cord Injury 101

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    Full Text Available ... Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC Understanding Spinal Cord Injury About Us Expert ... Disabilities Photography by Rona Talcott Website by Mobile Marketing LLC close close

  13. Spinal Cord Injury 101

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    Full Text Available ... cord injuries? play_arrow What are the latest developments in the use of electrical stimulation for spinal ... health care products or services, or control the information found on external websites. The Hill Foundation is ...

  14. Spinal Cord Tumor

    Science.gov (United States)

    ... that may be more likely to affect the spine include breast, lung, prostate and multiple myeloma. Complications Both noncancerous and cancerous spinal tumors can compress the spinal cord and nerves, leading ...

  15. Spinal Cord Infarction

    Science.gov (United States)

    ... Information from the National Library of Medicine’s MedlinePlus Spinal Cord Injuries Show More Show Less Search Disorders Search NINDS SEARCH SEARCH Definition Treatment Prognosis Clinical Trials Organizations Publications Definition Spinal ...

  16. Spinal Cord Injury 101

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    Full Text Available ... Experiences By Topic Resources Blog Peer ... cord injuries. The website does not provide medical advice, recommend or endorse health care products or services, or control the information ...

  17. Spinal Cord Injury 101

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    Full Text Available ... How Peer Counseling Works Julie Gassaway, MS, RN Pediatric Injuries Pediatric Spinal Cord Injury 101 Lawrence Vogel, MD The Basics of Pediatric SCI Rehabilitation Sara Klaas, MSW Transitions for Children ...

  18. Spinal Cord Injury

    Science.gov (United States)

    ... hips, legs, and feet. If you have a spinal injury you may need surgery, physical therapy , and other ... your health on a daily basis. Living with spinal cord injury — your questions answered top What are pediatric ...

  19. Spinal Cord Injury 101

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    Full Text Available ... arrow What is the “Spinal Cord Injury Model Systems” program? play_arrow ... recommend or endorse health care products or services, or control the information found on external websites. The Hill Foundation is ...

  20. Spinal Cord Injury 101

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    Full Text Available ... Living with SCI Personal Experiences by Topic Resources Peer Counseling Blog About Media Donate close search Understanding ... Living with SCI Personal Experiences by Topic Resources Peer Counseling Blog About Media Donate Spinal Cord Injury ...

  1. Spinal Cord Injury 101

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    Full Text Available ... Life in a Wheelchair Lisa Rosen, MS Spasticity, Physical Therapy-Lokomat T. George Hornby, PhD, PT Empowering ... Rogers, SW Marguerite David, MSW Kathy Hulse, MSW Physical Therapy after Spinal Cord Injury Laura Wehrli, PT ...

  2. Spinal Cord Injury 101

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    Full Text Available ... SCI Rehabilitation Donald Peck Leslie, MD Adjusting to Social Life in a Wheelchair Lisa Rosen, MS Spasticity, ... OT Anne Bryden, OT The Role of the Social Worker after Spinal Cord Injury Patti Rogers, SW ...

  3. Spinal Cord Injury 101

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    Full Text Available ... Injury Diane M. Rowles, MS, NP How Family Life Changes After Spinal Cord Injury Nancy Rosenberg, PsyD ... Rehabilitation Donald Peck Leslie, MD Adjusting to Social Life in a Wheelchair Lisa Rosen, MS Spasticity, Physical ...

  4. Spinal Cord Injury 101

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    Full Text Available ... OT Anne Bryden, OT The Role of the Social Worker after Spinal Cord Injury Patti Rogers, ... not provide medical advice, recommend or endorse health care products or services, or control the information found on external websites. ...

  5. Spinal cord trauma

    Science.gov (United States)

    ... cord Fragments of metal (such as from a traffic accident or gunshot) Sideway pulling or pressing or ... depending on the location of the injury. SCI causes weakness and loss of feeling at, and below ...

  6. Spinal Cord Injury 101

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    Full Text Available ... play_arrow What does stem-cell research on animals tell us? play_arrow When can we expect ... com is an informational and support website for families facing spinal cord injuries. The website does not ...

  7. Spinal Cord Injury 101

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    Full Text Available ... Forms. FacingDisability.com is an informational and support website for families facing spinal cord injuries. The website does not provide medical advice, recommend or endorse ...

  8. Laryngeal Electromyography is Helpful for Cardiovocal Syndrome.

    Science.gov (United States)

    Akbulut, Sevtap; Inan, Rahsan; Demir, Mehmet Gökhan; Cakan, Dogan

    2016-01-01

    Laryngeal electromyography is used in the evaluation of vocal cord paralysis to confirm the diagnosis, to guide the diagnostic work-up for etiology, to provide prognostic information and to help choose the correct treatment for the patient. Cardiovocal syndrome is characterised by vocal cord paralysis due to a cardiovascular disease. A wide spectrum of conditions can result in this syndrome. Here we present a case of cardiovocal syndrome in association with primary pulmonary hypertension. Laryngeal electromyography was used to guide the work-up of differential diagnosis and also for further intervention with respect to vocal cord paralysis in this patient.

  9. Tethered Transition Metals Promoted Photocatalytic System for Efficient Hydrogen Evolutions

    KAUST Repository

    Takanabe, Kazuhiro

    2015-03-05

    The present invention is directed, at least in part, to a process for improving the efficiency of a photocatalyst (a semiconductor photocatalyst) by tethering (depositing) a metal (e.g., metal ions of a late transition metal, such as nickel) to the semiconductor (photocatalyst) surface through the use of an organic ligand. More specifically, 1,2-ethanedithiol (EDT) functions as an excellent molecular linker (organic ligand) to attach a transition metal complex (e.g., nickel (Ni.sup.2+ ions)) to the semiconductor surface, which can be in the form of a cadmium sulfide surface. The photocatalyst has particular utility in generating hydrogen from H.sub.2S.

  10. Flight control and stability of a multiple kites tethered system

    OpenAIRE

    Podgaets, A.R.; Ockels, W.J.

    2006-01-01

    One of novel concepts to use the energy of high altitude winds is by launching a series of kite on a long rope and let them pull the rope thus driving the generator. A mathematical model of tethered kites system has been developed consisting of models of kites and of the cable that links them together and to the generator on the ground energy station. The model described is then investigated for stability in various wind conditions including random wind gusts which require stochastic stabilit...

  11. Tethered bimolecular lipid membranes - A novel model membrane platform

    Energy Technology Data Exchange (ETDEWEB)

    Knoll, Wolfgang; Koeper, Ingo; Naumann, Renate; Sinner, Eva-Kathrin [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany)

    2008-10-01

    This contribution summarizes some of our efforts in designing, synthesizing, assembling, and characterizing functional tethered bimolecular lipid membranes (tBLMs) as a novel platform for biophysical studies of and with artificial membranes or for sensor development employing, e.g., membrane integral receptor proteins. Chemical coupling schemes based on thiol groups for Au substrates or silanes used in the case of oxide surfaces allow for the covalent and, hence, chemically and mechanically robust attachment of anchor lipids to the solid support, stabilizing the proximal layer of a tethered membrane on the transducer surface. Surface plasmon optics, the quartz crystal microbalance, fluorescence- and IR spectroscopies, and electrochemical techniques are used to characterize the build-up of these complex supramolecular interfacial architectures. We demonstrate, in particular, that bilayers with a specific electrical resistance of better than 10 M{omega} cm{sup 2} can be achieved routinely with this approach. The functionalization of the lipid membranes by the incorporation of peptides is demonstrated for the carrier valinomycin which shows in our tBLMs the expected discrimination by four orders of magnitude between the translocation of K{sup +}- and Na{sup +}-ions across the hydrophobic barrier. For the synthetic channel-forming peptide M2 the high electrical resistance of the bilayer with the correspondingly low background current allows for the recording of even single channel current fluctuations. From the many membrane proteins that we reconstituted so far we describe results obtained with the redox-protein cytochrome c oxidase. Here, we also use a genetically modified mutant with a His-tag at either the C- or the N-terminus for the oriented attachment of the protein via the NTA/Ni{sup 2+} approach. With this strategy, we not only can control the density of the immobilized functional units, we introduce a completely new and alternative concept for the

  12. Is "Delayed Umbilical Cord Clamping" Beneficial for Premature Newborns?

    Directory of Open Access Journals (Sweden)

    Amir-Mohammad Armanian

    2017-05-01

    Full Text Available Background: The appropriate moment for clamping the umbilical cord is controversial. Immediate cord clamping (ICC is an item of active management of the third stage of labor (AMTSL. Unclamped umbilical cord may cause inconvenience in preterm neonates because they commonly need some levels of emergent services. Some studies revealed delayed cord clamping (DCC of preterm neonates results in better health conditions like lower rates of respiratory distress syndrome (RDS, less morbidities in labor room and lower risk of postpartum hemorrhage. The aim of the present study was to determine the effect of delayed umbilical cord clamping on premature neonatal outcomes. Materials and Methods: In this single‑center randomized control trial study, sixty premature neonates (gestational age ≤ 34 weeks were randomly assigned to ICC (cord clamped at 5–10 seconds or DCC (30–45 seconds groups and followed up in neonatal intensive care unit (NICU. Primary outcomes were 1st and 5th minute Apgar score, average of level of hematocrit after birth, intra ventricle hemorrhage and need some levels of resuscitation. Results: Differences in demographic characteristics were not statistically significant. After birth, neonates who had delayed clamping had significantly higher mean hematocrit after at 4-hour of birth (49.58+5.15gr/dl vs. 46.58+5.40gr/dlin DCC vs. ICC groups, respectively (P=0.031. Delayed cord clamping reduced the duration of need to nasal continues positive airway pressure (NCPAP (86.7% and 60.0% in ICC and DCC groups, respectively, P= 0.039. Attractively, the results showed lower incidence of clinical sepsis in delayed cord clamping neonates (53.3% vs. 23.3% in ICC and DCC groups, respectively, P=0.033. Conclusion: Prematurity complications might decrease by delay umbilical cord clamping which improve the hematocrit, duration of need to NCPAP and incidence of clinical sepsis. Furthermore, DCC may have no negative impact on neonatal resuscitation.

  13. THE COMPLEX TREATMENT OF THE PATIENT WITH MULTIPLE SPINE AND SPINAL CORD MALFORMATIONS

    Directory of Open Access Journals (Sweden)

    S. V. Vissarionov

    2011-01-01

    Full Text Available Clinical case of the patient with the congenital deformation of thoracic and lumbar parts of the spine due to multiple congenital anomalies of vertebrae (disturbance of formation, fusion and segmentation, a terminale filum lipoma at the level of L5, tethered cord, rightside lower leg monoparesis. Multistage surgical treatment was performed: removing of intracanal deformity, correction and stabilization of the deformity at the thoracic and lumbar part of the spine. Patient was followed up during 2,5 years after the last step of the surgical operation. No evidence of recurrence or neurological deterioration were observed.

  14. Emerging insights into the roles of membrane tethers from analysis of whole organisms: The tip of an iceberg?

    Directory of Open Access Journals (Sweden)

    Wei Hong eToh

    2016-02-01

    Full Text Available Membrane tethers have been identified throughout different compartments of the endomembrane system. It is now well established that a number of membrane tethers mediate docking of membrane carriers in anterograde and retrograde transport and in regulating the organization of membrane compartments. Much of our information on membrane tethers have been obtained from the analysis of individual membrane tethers in cultured cells. In the future it will be important to better appreciate the network of interactions mediated by tethers and the potential co-ordination of their collective functions in vivo. There are now a number of studies which have analyzed membrane tethers in tissues and organisms which are providing new insights into the role of this class of membrane protein at the physiological level. Here we review recent advances in the understanding of the function of membrane tethers from knock outs (or knock downs in whole organisms and from mutations in tethers associated with disease.

  15. Dynamic modeling and Super-Twisting Sliding Mode Control for Tethered Space Robot

    Science.gov (United States)

    Zhao, Yakun; Huang, Panfeng; Zhang, Fan

    2018-02-01

    Recent years, tethered space capturing systems have been considered as one of the most promising solutions for active space debris removal due to the increasing threat of space debris to spacecraft and astronauts. In this paper, one of the tethered space capturing systems, Tethered Space Robot (TSR), is investigated. TSR includes a space platform, a space tether, and a gripper as the terminal device. Based on the assumptions that the platform and the gripper are point masses and the tether is rigid, inextensible and remaining straight, the dynamic model of TSR is presented, in which the disturbances from space environment is considered. According to the previous study, the in-plane and out-of-plane angles of the tether oscillate periodically although the tether is released to the desired length. A super-twisting adaptive sliding mode control scheme is designed for TSR to eliminate the vibration of the tether to assure a successful capture in station-keeping phase. Both uncontrolled and controlled situations are simulated. The simulation results show that the proposed controller is effective. Additionally, after comparing with normal sliding mode control algorithm, it is verified that the proposed control scheme can avoid the chattering of normal sliding mode control and is robust for unknown boundary perturbations.

  16. Label-free measurements of membrane tether thickness using optical tweezers combined with SLIM

    Science.gov (United States)

    Sarshar, Mohammad; Wong, Winson T.; Anvari, Bahman

    2015-03-01

    Various cellular activities such as motility, division, and endocytosis involve a change in the cell shape. The mechanical interactions between the cell membrane and cytoskeleton play an important role in regulating changes in the cell shape. Tether formation from cell membranes provides a technique to characterize the mechanical properties of cell membranes and membrane-cytoskeleton interactions. Accurate measurement of the nano-scale tether diameter is relevant to quantification of membrane tension, bending modulus, and adhesion energy of the membrane-cytoskeleton structure. We have integrated optical tweezers with quantitative phase imaging, based on spatial light interference microscopy (SLIM), to simultaneously form tethers from HEK-293 cells and measure their diameters. Tether thickness along the illumination axis was measured using the quantitative phase map of the sample, and the refractive index (RI) mismatch between the sample and the surrounding media. The RI of the tethers ranged from 1.354 to 1.368 (cell culture medium RI=1.337). Our SLIM imaging system provided a 38 nm resolution in tether thickness measurements. Tether diameter fluctuations of <100 nm were resolved on tethers that ranged between 600-900 nm in diameter. Our integrated platform also provides the ability to simultaneously manipulate and image cell organelles in a non-contact and marker-free manner at nanometer spatial resolution.

  17. The development and significance of abnormal stereotyped behaviours in tethered sows

    NARCIS (Netherlands)

    Cronin, G.M.

    1985-01-01

    The development and performance of abnormal stereotyped behaviours (stereotypies) by tethered sows were studied in order to investigate the consequences of the behaviours for animal welfare and sow productivity.

    In Chapter 2, the behaviour of 36 tethered sows in a commercial herd

  18. Acquisition of Ice-Tethered Profilers with Velocity (ITP-V) Instruments for Future Arctic Studies

    Science.gov (United States)

    2016-11-15

    San Diego, CA, IEEE Xplore . Toole, J. M., R. A. Krishfield, M.-L. Timmennans, and A. Proshutinsky, 2011: The Ice-Tethered Profiler: Argo ofthe Arctic, Oceanogr., 24, 126-135. 4 ...observations from Ice-Tethered Profilers, MTS/ IEEE Oceans’ 2015, Washington DC, 1-10. Krishfield, R., J. Toole, A. Proshutinsky, and M.-L. Timmennans, 2008

  19. Rolling neutrophils form tethers and slings under physiologic conditions in vivo.

    Science.gov (United States)

    Marki, Alex; Buscher, Konrad; Mikulski, Zbigniew; Pries, Axel; Ley, Klaus

    2017-08-18

    Human and mouse neutrophils are known to form tethers when rolling on selectins in vitro. Tethers are ∼0.2 μm thin, ∼5-10 μm-long structures behind rolling cells that can swing around to form slings that serve as self-adhesive substrates. Here, we developed a mouse intravital imaging method, where the neutrophil surface is labeled by injecting fluorescently labeled mAb to Ly-6G. Venules in the cremaster muscle of live mice were imaged at a high frame rate using a confocal microscope equipped with a fast resonant scanner. We observed 270 tethers (median length 3.5 μm) and 31 slings (median length 6.9 µm) on 186 neutrophils of 15 mice. Out of 199 tether break events, 123 were followed by immediate acceleration of the rolling cell, which shows that tethers are load-bearing structures in vivo. In venules with a high wall shear stress (WSS; > 12 dyn/cm2), median rolling velocity was higher (19 μm/s), and 43% of rolling neutrophils had visible tethers. In venules with WSS < 12 dyn/cm2, only 26% of rolling neutrophils had visible tethers. We conclude that neutrophil tethers are commonly present and stabilize rolling in vivo. © Society for Leukocyte Biology.

  20. Flexible Tethered Kite with Moveable Attachment Points, Part I: Dynamics and Control

    NARCIS (Netherlands)

    Williams, P.; Lansdorp, B.; Ockels, W.

    2007-01-01

    Tethered kite technology is one potential means of harnessing energy available in high altitude winds. In an efficient and practical system, the kite is required to fly in cyclic patterns that maximize net power produced per cycle. At the same time, the tether length must be controlled to ensure the

  1. In-plane adaptive retrieval control for a noncooperative target by tethered space robots

    Directory of Open Access Journals (Sweden)

    Zhongjie Meng

    2016-09-01

    Full Text Available Using tether to replace rigid arms, the tethered space robot has more flexibility and security than the traditional space robot, which gives it a wide application prospect in the satellite retrieval. After a noncooperative satellite is captured by the tethered space robot, the tethered space robot and the satellite compose a combination with uncertain mass, inertia, and tether junction position. The tether length, tether deflection, and combination attitude are coupled seriously and control inputs are strictly limited, which make the retrieval of tethered space robot very difficult. First, a retrieval dynamic model of in-plane motion is derived using Lagrangian method. Then, in order to solve the uncertainty problems of dynamics parameters, an adaptive controller and its parameter updating law are proposed using the dynamic inversion theory. Moreover, an anti-windup strategy with auxiliary variables is derived to compensate the limited control inputs. Simulation results validate the feasibility of the proposed adaptive anti-windup control method. The noncooperative satellite is retrieved along the desired trajectory effectively.

  2. Yolk granule tethering: a role in cell resealing and identification of several protein components.

    Science.gov (United States)

    McNeil, Anna; McNeil, Paul L

    2005-10-15

    Homotypic fusion among echinoderm egg yolk granules has previously been reconstituted in vitro, and shown to be a rapid, Ca2+-triggered reaction that can produce extremely large (>10 microm diameter) fusion products. We here show that, prior to Ca2+-triggered fusion, yolk granules in vitro, if isolated in an appropriate buffer, became tethered to one another, forming large aggregates of more than 100 granules. Granule washing with mildly chaotropic salt abolished this tethering reaction, and prevented Ca2+-triggered formation of the large fusion products characteristic of tethered granules. Protein factors present in the wash restored tethering activity and these factors could be substantially enriched by anion exchange chromatography. The enriched fraction behaved under native conditions as a high molecular weight (approximately 670 kDa), multisubunit complex of at least seven proteins. Monoclonal antibodies directed against this complex of proteins were capable of immunodepleting tethering activity, confirming the role of the complex in granule tethering. These antibodies selectively stained the surface of yolk granules in the intact egg. We therefore propose a new role for tethering: it can promote the formation of large vesicular fusion products, such as those required for successful resealing. We have, moreover, identified several proteins that may be critical to this tethering mechanism.

  3. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    Science.gov (United States)

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases.

  4. Piperidinium tethered nanoparticle-hybrid electrolyte for lithium metal batteries

    KAUST Repository

    Korf, Kevin S.

    2014-06-23

    We report on the synthesis of novel piperidinium-based ionic liquid tethered nanoparticle hybrid electrolytes and investigate their physical and electrochemical properties. Hybrid electrolytes based on the ionic liquid 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfone) imide covalently tethered to silica nanoparticles (SiO2-PP-TFSI) were blended with propylene carbonate-1 M lithium bis(trifluoromethanesulfone) imide (LiTFSI). We employed NMR analysis to confirm the successful creation of the hybrid material. Dielectric and rheological measurements show that these electrolytes exhibit exceptional room-temperature DC ionic conductivity (10-2 to 10 -3 S cm-1) as well as high shear mechanical moduli (105 to 106 Pa). Lithium transference numbers were found to increase with particle loading and to reach values as high as 0.22 at high particle loadings where the particle jam to form a soft glassy elastic medium. Analysis of lithium electrodeposits obtained in the hybrid electrolytes using SEM and EDX spectra show that the SiO2-PP-TFSI nanoparticles are able to smooth lithium deposition and inhibit lithium dendrite proliferation in Li metal batteries. LTOSiO2-PP-TFSI/PC in 1 M LiTFSILi half-cells based on the SiO2-PP-TFSI hybrid electrolytes exhibit attractive voltage profiles and trouble-free extended cycling behavior over more than 1000 cycles of charge and discharge. This journal is © the Partner Organisations 2014.

  5. Dynamics of tethered versus free-swimming animals: A wake structure comparison in jellyfish

    Science.gov (United States)

    Katija, Kakani; Dabiri, John O.

    2006-11-01

    Previous research has shown that jellyfish utilize the formation and shedding of vortices to help feed and move the animal. Laboratory experiments often require restricting the motion of an animal by tethering/fluming to allow for repeatable results. However, past research has not addressed the differences that arise when the motion of an animal is restricted/confined. This presentation will attend to this issue by comparing the wake structure of a tethered and free-swimming Aurelia aurita. Digital Particle Image Velocimetry is used to collect measurements of the velocity field surrounding an animal that is either tethered or swimming freely. Dynamical systems methods are used to compute Lagrangian coherent structures (LCS), which is used to identify the geometries of structures in the wake of the animal. Using LCS, a comparison between the wake of a tethered and free-swimming animal can be made. This research provides a quantitative measure of the differences between a tethered and freely moving jellyfish.

  6. Transport vesicle tethering at the trans Golgi network: coiled coil proteins in action

    Directory of Open Access Journals (Sweden)

    Pak-yan Patricia Cheung

    2016-03-01

    Full Text Available The Golgi complex is decorated with so-called Golgin proteins that share a common feature: a large proportion of their amino acid sequences are predicted to form coiled-coil structures. The possible presence of extensive coiled coils implies that these proteins are highly elongated molecules that can extend a significant distance from the Golgi surface. This property would help them to capture or trap inbound transport vesicles and to tether Golgi mini-stacks together. This review will summarize our current understanding of coiled coil tethers that are needed for the receipt of transport vesicles at the trans Golgi network. How do long tethering proteins actually catch vesicles? Golgi-associated, coiled coil tethers contain numerous binding sites for small GTPases, SNARE proteins, and vesicle coat proteins. How are these interactions coordinated and are any or all of them important for the tethering process? Progress towards understanding these questions and remaining, unresolved mysteries will be discussed.

  7. Interplay of matrix stiffness and protein tethering in stem cell differentiation.

    Science.gov (United States)

    Wen, Jessica H; Vincent, Ludovic G; Fuhrmann, Alexander; Choi, Yu Suk; Hribar, Kolin C; Taylor-Weiner, Hermes; Chen, Shaochen; Engler, Adam J

    2014-10-01

    Stem cells regulate their fate by binding to, and contracting against, the extracellular matrix. Recently, it has been proposed that in addition to matrix stiffness and ligand type, the degree of coupling of fibrous protein to the surface of the underlying substrate, that is, tethering and matrix porosity, also regulates stem cell differentiation. By modulating substrate porosity without altering stiffness in polyacrylamide gels, we show that varying substrate porosity did not significantly change protein tethering, substrate deformations, or the osteogenic and adipogenic differentiation of human adipose-derived stromal cells and marrow-derived mesenchymal stromal cells. Varying protein-substrate linker density up to 50-fold changed tethering, but did not affect osteogenesis, adipogenesis, surface-protein unfolding or underlying substrate deformations. Differentiation was also unaffected by the absence of protein tethering. Our findings imply that the stiffness of planar matrices regulates stem cell differentiation independently of protein tethering and porosity.

  8. The development of optimal control laws for orbiting tethered platform systems

    Science.gov (United States)

    Bainum, P. M.

    1986-01-01

    A mathematical model of the open and closed loop in orbit plane dynamics of a space platform-tethered-subsatellite system is developed. The system consists of a rigid platform from which an (assumed massless) tether is deploying (retrieving) a subsatellite from an attachment point which is, in general, offset from the platform's mass center. A Langrangian formulation yields equations describing platform pitch, subsatellite tetherline swing, and varying tether length motions. These equations are linearized about the nominal station keeping motion. Control can be provided by both modulation of the tether tension level and by a momentum type platform-mounted device; system controllability depends on the presence of both control inputs. Stability criteria are developed in terms of the control law gains, the platform inertia ratio, and tether offset parameter. Control law gains are obtained based on linear quadratic regulator techniques. Typical transient responses of both the state and required control effort are presented.

  9. Diffusive transport of molecular cargo tethered to a DNA origami platform.

    Science.gov (United States)

    Kopperger, Enzo; Pirzer, Tobias; Simmel, Friedrich C

    2015-04-08

    Fast and efficient transport of molecular cargoes along tracks or on supramolecular platforms is an important prerequisite for the development of future nanorobotic systems and assembly lines. Here, we study the diffusive transport of DNA cargo strands bound to a supramolecular DNA origami structure via an extended tether arm. For short distances (on the order of a few nanometers), transport from a start to a target site is found to be less efficient than for direct transfer without tether. For distances on the scale of the origami platform itself, however, cargo transfer mediated by a rigid tether arm occurs very fast and robust, whereas a more flexible, hinged tether is found to be considerably less efficient. Our results suggest diffusive motion on a molecular tether as a highly efficient mechanism for fast transfer of cargoes over long distances.

  10. Shortest Path Planning for a Tethered Robot or an Anchored Cable

    Energy Technology Data Exchange (ETDEWEB)

    Xavier, P.G.

    1999-02-22

    We consider the problem of planning shortest paths for a tethered robot with a finite length tether in a 2D environment with polygonal obstacles. We present an algorithm that runs in time O((k{sub 1} + 1){sup 2}n{sup 4}) and finds the shortest path or correctly determines that none exists that obeys the constraints; here n is the number obstacle vertices, and k{sub 1} is the number loops in the initial configuration of the tether. The robot may cross its tether but nothing can cross obstacles, which cause the tether to bend. The algorithm applies as well for planning a shortest path for the free end of an anchored cable.

  11. Canine spinal cord glioma.

    Science.gov (United States)

    Rissi, Daniel R; Barber, Renee; Burnum, Annabelle; Miller, Andrew D

    2017-01-01

    Spinal cord glioma is uncommonly reported in dogs. We describe the clinicopathologic and diagnostic features of 7 cases of canine spinal cord glioma and briefly review the veterinary literature on this topic. The median age at presentation was 7.2 y. Six females and 1 male were affected and 4 dogs were brachycephalic. The clinical course lasted from 3 d to 12 wk, and clinical signs were progressive and associated with multiple suspected neuroanatomic locations in the spinal cord. Magnetic resonance imaging of 6 cases revealed T2-weighted hyperintense lesions with variable contrast enhancement in the spinal cord. All dogs had a presumptive clinical diagnosis of intraparenchymal neoplasia or myelitis based on history, advanced imaging, and cerebrospinal fluid analysis. Euthanasia was elected in all cases because of poor outcome despite anti-inflammatory or immunosuppressive treatment or because of poor prognosis at the time of diagnosis. Tumor location during autopsy ranged from C1 to L6, with no clear predilection for a specific spinal cord segment. The diagnosis was based on histopathology and the immunohistochemistry expression of glial fibrillary acidic protein, oligodendrocyte lineage transcription factor 2, 2',3'-cyclic-nucleotide 3'-phosphodiesterase, neuron-specific enolase, synaptophysin, and Ki-67. Diagnoses consisted of 4 cases of oligodendroglioma, 2 cases of gliomatosis cerebri, and 1 astrocytoma. This case series further defines the clinicopathologic features of canine spinal glioma and highlights the need for comprehensive immunohistochemistry in addition to routine histopathology to confirm the diagnosis of these tumors.

  12. Geometrical variations in white and gray matter affect the biomechanics of spinal cord injuries more than the arachnoid space

    Directory of Open Access Journals (Sweden)

    Léo Fradet

    2016-08-01

    Full Text Available Traumatic spinal cord contusions lead to loss of quality of life, but their pathomechanisms are not fully understood. Previous studies have underlined the contribution of the cerebrospinal fluid in spinal cord protection. However, it remains unclear how important the contribution of the cerebrospinal fluid is relative to other factors such as the white/gray matter ratio. A finite element model of the spinal cord and surrounding morphologic features was used to investigate the spinal cord contusion mechanisms, considering subarachnoid space and white/gray matter ratio. Two vertebral segments (T6 and L1 were impacted transversely at 4.5 m s−1, which demonstrated three major results: While the presence of cerebrospinal fluid plays a significant contributory role in spinal cord protection (compression percentage decreased by up to 19%, the arachnoid space variation along the spine appears to have a limited (3% compression decrease impact. Differences in the white and gray matter geometries from lumbar to thoracic spine levels decrease spinal cord compression by up to 14% at the thoracic level. Stress distribution in the sagittal spinal cord section was consistent with central cord syndrome, and local stress concentration on the anterior part of the spinal cord being highly reduced by the presence of cerebrospinal fluid. The use of a refined spinal cord finite element method showed that all the geometrical parameters are involved in the spinal cord contusion mechanisms. Hence, spinal cord injury criteria must be considered at each vertebral level.

  13. Neurological and spinal manifestations of the Ehlers-Danlos syndromes.

    Science.gov (United States)

    Henderson, Fraser C; Austin, Claudiu; Benzel, Edward; Bolognese, Paolo; Ellenbogen, Richard; Francomano, Clair A; Ireton, Candace; Klinge, Petra; Koby, Myles; Long, Donlin; Patel, Sunil; Singman, Eric L; Voermans, Nicol C

    2017-03-01

    The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable connective tissue disorders characterized by joint hypermobility, skin extensibility, and tissue fragility. This communication briefly reports upon the neurological manifestations that arise including the weakness of the ligaments of the craniocervical junction and spine, early disc degeneration, and the weakness of the epineurium and perineurium surrounding peripheral nerves. Entrapment, deformation, and biophysical deformative stresses exerted upon the nervous system may alter gene expression, neuronal function and phenotypic expression. This report also discusses increased prevalence of migraine, idiopathic intracranial hypertension, Tarlov cysts, tethered cord syndrome, and dystonia, where associations with EDS have been anecdotally reported, but where epidemiological evidence is not yet available. Chiari Malformation Type I (CMI) has been reported to be a comorbid condition to EDS, and may be complicated by craniocervical instability or basilar invagination. Motor delay, headache, and quadriparesis have been attributed to ligamentous laxity and instability at the atlanto-occipital and atlantoaxial joints, which may complicate all forms of EDS. Discopathy and early degenerative spondylotic disease manifest by spinal segmental instability and kyphosis, rendering EDS patients prone to mechanical pain, and myelopathy. Musculoskeletal pain starts early, is chronic and debilitating, and the neuromuscular disease of EDS manifests symptomatically with weakness, myalgia, easy fatigability, limited walking, reduction of vibration sense, and mild impairment of mobility and daily activities. Consensus criteria and clinical practice guidelines, based upon stronger epidemiological and pathophysiological evidence, are needed to refine diagnosis and treatment of the various neurological and spinal manifestations of EDS. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Depression and Spinal Cord Injury

    Science.gov (United States)

    ... Urinary Tract Infections: Indwelling (Foley) Catheter Depression and Spinal Cord Injury [ Download this pamphlet: “Depression and Spinal Cord Injury” (PDF - 477KB)] Depression is a common illness that ...

  15. Umbilical cord care in newborns

    Science.gov (United States)

    ... Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Umbilical cord care in newborns URL of this page: //medlineplus.gov/ency/article/001926.htm Umbilical cord care in newborns To ...

  16. Spinal cord swelling and candidiasis

    Energy Technology Data Exchange (ETDEWEB)

    Ho, K.; Gronseth, G.; Aldrich, M.; Williams, A.

    1982-11-01

    Fusiform swelling of the spinal cord was noted myelographically in a patient with Hodgkin's disease. Autopsy revealed that the swelling was caused by Candida infection of the spinal cord. It is suggested that fungal infection be included in the differential diagnosis of spinal cord swelling in the immunosuppressed cancer patient.

  17. Structural and functional plasticity of subcellular tethering, targeting and processing of RPGRIP1 by RPGR isoforms

    Directory of Open Access Journals (Sweden)

    Hemangi Patil

    2012-02-01

    Mutations affecting the retinitis pigmentosa GTPase regulator-interacting protein 1 (RPGRIP1 interactome cause syndromic retinal dystrophies. RPGRIP1 interacts with the retinitis pigmentosa GTPase regulator (RPGR through a domain homologous to RCC1 (RHD, a nucleotide exchange factor of Ran GTPase. However, functional relationships between RPGR and RPGRIP1 and their subcellular roles are lacking. We show by molecular modeling and analyses of RPGR disease-mutations that the RPGR-interacting domain (RID of RPGRIP1 embraces multivalently the shared RHD of RPGR1–19 and RPGRORF15 isoforms and the mutations are non-overlapping with the interface found between RCC1 and Ran GTPase. RPGR disease-mutations grouped into six classes based on their structural locations and differential impairment with RPGRIP1 interaction. RPGRIP1α1 expression alone causes its profuse self-aggregation, an effect suppressed by co-expression of either RPGR isoform before and after RPGRIP1α1 self-aggregation ensue. RPGR1–19 localizes to the endoplasmic reticulum, whereas RPGRORF15 presents cytosolic distribution and they determine uniquely the subcellular co-localization of RPGRIP1α1. Disease mutations in RPGR1–19, RPGRORF15, or RID of RPGRIP1α1, singly or in combination, exert distinct effects on the subcellular targeting, co-localization or tethering of RPGRIP1α1 with RPGR1–19 or RPGRORF15 in kidney, photoreceptor and hepatocyte cell lines. Additionally, RPGRORF15, but not RPGR1–19, protects the RID of RPGRIP1α1 from limited proteolysis. These studies define RPGR- and cell-type-dependent targeting pathways with structural and functional plasticity modulating the expression of mutations in RPGR and RPGRIP1. Further, RPGR isoforms distinctively determine the subcellular targeting of RPGRIP1α1, with deficits in RPGRORF15-dependent intracellular localization of RPGRIP1α1 contributing to pathomechanisms shared by etiologically distinct syndromic retinal dystrophies.

  18. Delayed cord clamping and cord gas analysis at birth.

    Science.gov (United States)

    Xodo, Serena; Xodo, Luigi; Berghella, Vincenzo

    2018-01-01

    Delayed cord clamping for at least 60 s in both term and preterm babies is a major recent change in clinical care. Delayed cord clamping has several effects on other possible interventions. One of these is the effect of delayed cord clamping on umbilical artery gas analysis. When indicated, umbilical artery gas analysis can safely be done either with early cord clamping or, probably most of the times it is necessary, during delayed cord clamping with the cord still unclamped. Paired blood samples (one from the umbilical artery and one from the umbilical vein) can be taken from the pulsating and unclamped cord, immediately after birth, during delayed cord clamping, without any effect on either the accuracy of umbilical artery gas analysis or the transfusion of blood through delayed cord clamping. Umbilical artery gas analysis should instead not be done after delayed cord clamping, since delayed cord clamping alters several acid-based parameters and lactate values. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

  19. Recognition and tethering of transport vesicles at the Golgi apparatus.

    Science.gov (United States)

    Witkos, Tomasz M; Lowe, Martin

    2017-08-01

    The Golgi apparatus occupies a central position within the secretory pathway where it is a hub for vesicle trafficking. Distinct classes of transport vesicles traffic diverse cargoes into and out of this organelle, as well as between the different Golgi subcompartments. A key feature of Golgi trafficking is the specific recognition of transport vesicles at the different regions of the Golgi apparatus, required for the correct cargo delivery. Specificity is ensured by coiled-coil golgins and multi-subunit tethering complexes (MTCs), which act together to capture vesicles and promote their subsequent fusion with the Golgi membrane. In this review we discuss our current understanding of how golgins and MTCs function together to mediate the specific recognition of vesicles at the Golgi apparatus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Metal-ligand cooperation at tethered π-ligands.

    Science.gov (United States)

    Verhoeven, Dide G A; Moret, Marc-Etienne

    2016-10-12

    Metal-ligand cooperativity in homogeneous catalysis is emerging as a powerful tool for the design of efficient transition-metal catalysts. This perspective highlights recent advances in the use of neutral π-coordinating ligands, tethered to a transition-metal center by other donor ligands, as cooperative reaction centers. The state-of-the-art organometallic complexes, including π-coordinating ligands originating from C[double bond, length as m-dash]C, C[double bond, length as m-dash]E (E = O, N) and boron containing moieties, are described here, with special attention on their specific reactivity. Geometric and electronic aspects of ligand design and their influence on the coordination mode and reactivity of the π-system are discussed.

  1. Physisorbed Polymer-Tethered Lipid Bilayer with Lipopolymer Gradient

    Directory of Open Access Journals (Sweden)

    Christoph A. Naumann

    2012-11-01

    Full Text Available Physisorbed polymer-tethered lipid bilayers consisting of phospholipids and lipopolymers represent an attractive planar model membrane platform, in which bilayer fluidity and membrane elastic properties can be regulated through lipopolymer molar concentration. Herein we report a method for the fabrication of such a planar model membrane system with a lateral gradient of lipopolymer density. In addition, a procedure is described, which leads to a sharp boundary between regions of low and high lipopolymer molar concentrations. Resulting gradients and sharp boundaries are visualized on the basis of membrane buckling structures at elevated lipopolymer concentrations using epifluorescence microscopy and atomic force microscopy. Furthermore, results from spot photobleaching experiments are presented, which provide insight into the lipid lateral fluidity in these model membrane architectures. The presented experimental data highlight a planar, solid-supported membrane characterized by fascinating length scale-dependent dynamics and elastic properties with remarkable parallels to those observed in cellular membranes.

  2. DOE Geothermal Data Repository - Tethering Data to Information: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Weers, J.; Anderson, A.

    2014-02-01

    Data are not inherently information. Without context, data are just numbers, figures, names, or points on a line. By assigning context to data, we can validate ideas, form opinions, and generate knowledge. This is an important distinction to information scientists, as we recognize that the context in which we keep our data plays a big part in generating its value. The mechanisms used to assign this context often include their own data, supplemental to the data being described and defining semantic relationships, commonly referred to as metadata. This paper provides the status of the DOE Geothermal Data Repository (DOE GDR), including recent efforts to tether data submissions to information, discusses the important distinction between data and information, outlines a path to generate useful knowledge from raw data, and details the steps taken in order to become a node on the National Geothermal Data System (NGDS).

  3. Circular Orbit Target Capture Using Space Tether-Net System

    Directory of Open Access Journals (Sweden)

    Guang Zhai

    2013-01-01

    Full Text Available The space tether-net system for on-orbit capture is proposed in this paper. In order to research the dynamic behaviors during system deployment, both free and nonfree deployment dynamics in circular orbit are developed; the system motion with respect to Local Vertical and Local Horizontal frame is also researched with analysis and simulation. The results show that in the case of free deployment, the capture net follows curve trajectories due to the relative orbit dynamic perturbation, and the initial deployment velocities are planned by state transformation equations for static and floating target captures; in the case of non-free deployment, the system undergoes an altitude libration along the Local Vertical, and the analytical solutions that describe the attitude libration are obtained by using variable separation and integration. Finally, the dynamics of postdeployment system is also proved marginally stable if the critical initial conditions are satisfied.

  4. Tethered and Polymer Supported Bilayer Lipid Membranes: Structure and Function

    Directory of Open Access Journals (Sweden)

    Jakob Andersson

    2016-05-01

    Full Text Available Solid supported bilayer lipid membranes are model systems to mimic natural cell membranes in order to understand structural and functional properties of such systems. The use of a model system allows for the use of a wide variety of analytical tools including atomic force microscopy, impedance spectroscopy, neutron reflectometry, and surface plasmon resonance spectroscopy. Among the large number of different types of model membranes polymer-supported and tethered lipid bilayers have been shown to be versatile and useful systems. Both systems consist of a lipid bilayer, which is de-coupled from an underlying support by a spacer cushion. Both systems will be reviewed, with an emphasis on the effect that the spacer moiety has on the bilayer properties.

  5. The Effect of Tethers on Artificial Cell Membranes: A Coarse-Grained Molecular Dynamics Study.

    Directory of Open Access Journals (Sweden)

    William Hoiles

    Full Text Available Tethered bilayer lipid membranes (tBLMs provide a stable platform for modeling the dynamics and order of biological membranes where the tethers mimic the cytoskeletal supports present in biological cell membranes. In this paper coarse-grained molecular dynamics (CGMD is applied to study the effects of tethers on lipid membrane properties. Using results from the CGMD model and the overdamped Fokker-Planck equation, we show that the diffusion tensor and particle density of water in the tBLM is spatially dependent. Further, it is shown that the membrane thickness, lipid diffusion, defect density, free energy of lipid flip-flop, and membrane dielectric permittivity are all dependent on the tether density. The numerically computed results from the CGMD model are in agreement with the experimentally measured results from tBLMs containing different tether densities and lipids derived from Archaebacteria. Additionally, using experimental measurements from Escherichia coli bacteria and Saccharomyces Cerevisiae yeast tethered membranes, we illustrate how previous molecular dynamics results can be combined with the proposed model to estimate the dielectric permittivity and defect density of these membranes as a function of tether density.

  6. Probing tethered targets of a single biomolecular complex with atomic force microscopy.

    Science.gov (United States)

    Wu, Na; Wang, Qi; Zhou, Xingfei; Jia, Si Si; Fan, Youjie; Hu, Jun; Li, Bin

    2013-12-01

    DNA origami shows tremendous promise as templates for the assembly of nano-components and detection of molecular recognition events. So far, the method of choice for evaluating these structures has been atomic force microscopy (AFM), a powerful tool for imaging nanoscale objects. In most cases, tethered targets on DNA origami have proven to be highly effective samples for investigation. Still, while maximal assembly of the nanostructures might benefit from the greatest flexibility in the tether, AFM imaging requires a sufficient stability of the adsorbed components. The balance between the tether flexibility and sample stability is a major, poorly understood, concern in such studies. Here, we investigated the dependence of the tethering length on molecular capture events monitored by AFM. In our experiments, single biotin molecules were attached to DNA origami templates with various linker lengths of thymidine nucleotides, and their interaction with streptavidin was observed with AFM. Our results show that the streptavidin-biotin complexes are easily detected with short tethered lengths, and that their morphological features clearly change with the tethering length. We identify the functionally useful tether lengths for these investigations, which are also expected to prove useful in the construction and further application of DNA origami in bio-nanotechnology studies. Copyright © 2013 John Wiley & Sons, Ltd.

  7. Viewpoint animation with a dynamic tether for supporting navigation in a virtual environment.

    Science.gov (United States)

    Wang, Wenbi; Milgram, Paul

    2009-06-01

    This study examined the concept of dynamic viewpoint tethering for enhancing performance in 3-D avatar control tasks. Dynamic viewpoint tethering refers to a viewpoint animation technique that couples a display viewpoint to a controlled avatar through a virtual tether. A dynamic tether, modeled as a mass spring damper system, can potentially generate desirable viewpoint behavior because of its ability to produce frequency-separated viewpoint responses. This study investigated the impact of a tether's rigidity and damping properties on users' navigational performance. Twelve participants took part in a simulated 3-D aerial navigational task. Performance was evaluated with respect to local guidance and global awareness. Root mean square error scores revealed a decrease in local guidance performance when (a) the tether was either severely underdamped or overdamped and (b) the tether's rigidity approached either zero or infinity. In addition, (c) global performance was better for higher-frequency forcing functions. Critical damping and medium rigidity can be optimized during design for enhancing users' navigational efficiency. Guidelines generated from this study support future viewpoint design in interactive virtual reality applications.

  8. Heterobifunctional crosslinkers for tethering single ligand molecules to scanning probes

    Energy Technology Data Exchange (ETDEWEB)

    Riener, Christian K.; Kienberger, Ferry; Hahn, Christoph D.; Buchinger, Gerhard M.; Egwim, Innocent O.C.; Haselgruebler, Thomas; Ebner, Andreas; Romanin, Christoph; Klampfl, Christian; Lackner, Bernd; Prinz, Heino; Blaas, Dieter; Hinterdorfer, Peter; Gruber, Hermann J

    2003-11-14

    Single molecule recognition force microscopy (SMRFM) is a versatile atomic force microscopy (AFM) method to probe specific interactions of cognitive molecules on the single molecule level. It allows insights to be gained into interaction potentials and kinetic barriers and is capable of mapping interaction sites with nm positional accuracy. These applications require a ligand to be attached to the AFM tip, preferably by a distensible poly(ethylene glycol) (PEG) chain between the measuring tip and the ligand molecule. The PEG chain greatly facilitates specific binding of the ligand to immobile receptor sites on the sample surface. The present study contributes to tip-PEG-ligand tethering in three ways: (i) a convenient synthetic route was found to prepare NH{sub 2}-PEG-COOH which is the key intermediate for long heterobifunctional crosslinkers; (ii) a variety of heterobifunctional PEG derivatives for tip-PEG-ligand linking were prepared from NH{sub 2}-PEG-COOH; (iii) in particular, a new PEG crosslinker with one thiol-reactive end and one terminal nitrilotriacetic acid (NTA) group was synthesized and successfully used to tether His{sub 6}-tagged protein molecules to AFM tips via noncovalent NTA-Ni{sup 2+}-His{sub 6} bridges. The new crosslinker was applied to link a recombinant His{sub 6}-tagged fragment of the very-low density lipoprotein receptor to the AFM tip whereupon specific docking to the capsid of human rhinovirus particles was observed by force microscopy. In a parallel study, the specific interaction of the small GTPase Ran with the nuclear import receptor importin {beta}1 was studied in detail by SMRFM, using the new crosslinker to link His{sub 6}-tagged Ran to the measuring tip [Nat. Struct. Biol. (2003), 10, 553-557].

  9. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... play_arrow What is the “Spinal Cord Injury Model Systems” program? play_arrow What are the most ... Experiences By Topic Resources Blog Peer Counseling About Media Donate Contact Us Terms of Use Site Map ...

  10. Spinal Cord Injury 101

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    Full Text Available ... Life in a Wheelchair Lisa Rosen, MS Spasticity, Physical Therapy-Lokomat T. George Hornby, PhD, PT Empowering the ... Rogers, SW Marguerite David, MSW Kathy Hulse, MSW Physical Therapy after Spinal Cord Injury Laura Wehrli, PT Isa ...

  11. Spinal Cord Injury 101

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    Full Text Available ... Braingate” research? play_arrow How would stem-cell therapies work in the treatment of spinal cord injuries? play_arrow What does stem-cell research on animals tell us? play_arrow When can we expect ...

  12. Spinal Cord Injury 101

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    Full Text Available ... play_arrow What is the “Spinal Cord Injury Model Systems” program? play_arrow What are the most ... 2011 – 2017 Hill Foundation for Families Living With Disabilities Photography by Rona Talcott Website by Mobile Marketing ...

  13. Spinal Cord Injury 101

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    Full Text Available ... is “Braingate” research? play_arrow How would stem-cell therapies work in the treatment of spinal cord injuries? play_arrow What does stem-cell research on animals tell us? play_arrow When ...

  14. Spinal Cord Injury

    Science.gov (United States)

    ... stimulation to produce actions. They're often called functional electrical stimulation (FES) systems, and they use electrical stimulators to control arm and leg muscles to allow people with a spinal cord injury to stand, walk, reach and grip. Robotic gait ...

  15. Spinal Cord Injury 101

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    Full Text Available ... What is “Braingate” research? play_arrow How would stem-cell therapies work in the treatment of spinal cord injuries? play_arrow What does stem-cell research on animals tell us? play_arrow ...

  16. Spinal Cord Injury 101

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    Full Text Available ... Use Site Map Privacy Statement 312-284-2525 info@facingdisability.com SIGN UP FOR OUR NEWSLETTER Your ... spinal cord injuries Peer Counseling 312-284-2525 info@facingdisability.com SIGN UP FOR OUR NEWSLETTER Your ...

  17. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... What is “Braingate” research? play_arrow How would stem-cell therapies work in the treatment of spinal cord injuries? play_arrow What does stem-cell research on animals tell us? play_arrow When ...

  18. Spinal Cord Injury 101

    Medline Plus

    Full Text Available ... Blog Videos By Topic Media Resources Donate to support families facing spinal cord injuries Peer Counseling 312-284-2525 info@facingdisability.com SIGN UP FOR OUR NEWSLETTER Your email address * This iframe contains the logic required to ...

  19. Electrodynamic Tether Operations beyond the Ionosphere in the Low-Density Magnetosphere

    Science.gov (United States)

    Stone, Nobie H.

    2007-01-01

    In the classical concept for the operation of electrodynamic tethers in space, a voltage is generated across the tether, either by the tether's orbital motion through the earth's planetary magnetic field or by a power supply; electrons are then collected from the ionospheric plasma at the positive pole; actively emitted back into space at the negative pole; and the circuit is closed by currents driven through the ambient conducting ionosphere. This concept has been proven to work in space by the Tethered Satellite System TSS-1 and TSS-1R Space Shuttle missions; and the Plasma Motor-Generator (PMG) tether flight experiment. However, it limits electrodynamic tether operations to the F-region of the ionosphere where the plasma density is sufficient to conduct the required currents--in other words, between altitudes of approximately 200 to 1000 km in sunlight. In the earth's shadow, the ionospheric density drops precipitously and tether operations, using the above approach, are not effective--even within this altitude range. There are numerous missions that require in-space propulsion in the Earth's shadow and/or outside of the above altitude range. This paper will, therefore, present the fundamentals of a concept that would allow electrodynamic tethers to operate almost anywhere within the magnetosphere, the region of space containing the earth's planetary magnetic field. In other words, because operations would be virtually independent of any ambient plasma, the range of electrodynamic operations would be extended into the earth's shadow and out to synchronous orbit--forty times the present operational range. The key to this concept is the active generation of plasma at each pole of the tether so that current generation ,does not depend on the conductivity of the ambient ionosphere. Arguments will be presented, based on ,existing flight data, which shed light on the behavior of charge emissions in space and show the plausibility of the concept.

  20. Untethering an unusual cause of kidney injury in a teenager with Down syndrome.

    Science.gov (United States)

    Yen, Elizabeth; Miele, Niel F; Barone, Joseph G; Tyagi, Rachana; Weiss, Lynne S

    2014-11-01

    Acute kidney injury (AKI) is characterized by the acute nature and the inability of kidneys to maintain fluid homeostasis as well as adequate electrolyte and acid-base balance, resulting in an accumulation of nitrogenous waste and elevation of serum blood urea nitrogen and creatinine values. Acute kidney injury may be a single isolated event, yet oftentimes, it results from an acute chronic kidney disease. It is critical to seek out the etiology of AKI and to promptly manage the underlying chronic kidney disease to prevent comorbidities and mortality that may ensue. We described a case of a 16-year-old adolescent girl with Down syndrome who presented with AKI and electrolyte aberrance.Abdominal and renal ultrasounds demonstrated a significantly dilated bladder as well as frank hydronephrosis and hydroureter bilaterally. Foley catheter was successful in relieving the obstruction and improving her renal function. However, a magnetic resonance imaging was pursued in light of her chronic constipation and back pain, and it revealed a structural defect (tethered cord) that underlies a chronic process that was highly likely contributory to her AKI. She was managed accordingly with a guarded result and required long-term and close monitoring.

  1. Subcutaneous Stimulation as an Additional Therapy to Spinal Cord Stimulation for the Treatment of Low Back Pain and Leg Pain in Failed Back Surgery Syndrome: Four-Year Follow-Up.

    Science.gov (United States)

    Hamm-Faber, Tanja E; Aukes, Hans; van Gorp, Eric-Jan; Gültuna, Ismail

    2015-10-01

    The objective of this study is to investigate the efficacy of long-term follow-up of subcutaneous stimulation (SubQ) as an additional therapy for patients with failed back surgery syndrome (FBSS) with chronic refractory pain, for whom spinal cord stimulation (SCS) alone was unsuccessful in treating low back pain. Prospective case series. FBSS patients with leg and/or low back pain whose conventional therapies had failed, received a combination of SCS (8-contact Octad lead, 3877-45 cm, Medtronic, Minneapolis, MN, USA) and/or SubQ (4-contact Quad Plus lead (s), 2888-28 cm, Medtronic). Initially, an Octad lead was placed in the epidural space for SCS for a trial stimulation to assess the suppression of leg and/or low back pain. Where SCS alone was insufficient in treating low back pain, lead(s) were placed superficially in the subcutaneous tissue of the lower back, exactly in the middle of the pain area. A pulse generator (Prime Advanced, 37702, Medtronic) was implanted if the patient reported more than 50% pain relief during the trial period. We investigated the long-term effect of neuromodulation on pain with the visual analog scale (VAS), and disability using the Quebec Pain Disability Scale. The results after 46 months are presented. Eleven patients, five men and six women (age 51 ± 8 years, mean ± SD) were included in the pilot study. In nine cases, SCS was used in combination with SubQ leads. Two patients received only SubQ leads. In one patient, the SCS + SubQ system was removed after nine months and these results were not taken into account for the analysis. Baseline scores for leg (N = 8) and low back pain (N = 10) were VASbl: 59 ± 15 and VASbl: 63 ± 14, respectively. The long-term follow-up period was 46 ± 4 months. SCS significantly reduced leg pain after 12 months (VAS12: 20 ± 11, p12 = 0.001) and 46 months (VAS46: 37 ± 17, p46 = 0.027). Similarly, SubQ significantly reduced back pain after 12 months(VAS12: 33 ± 16, p12 = 0.001) and 46 months

  2. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    Science.gov (United States)

    Angelici, Robert J.; Gao, Hanrong

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical.

  3. Magnetic Resonance Imaging Analysis of Caudal Regression Syndrome and Concomitant Anomalies in Pediatric Patients

    Directory of Open Access Journals (Sweden)

    Deb K Boruah

    2016-01-01

    Full Text Available Objective: The aim of this study was to evaluate the magnetic resonance imaging (MRI findings of caudal regression syndrome (CRS and concomitant anomalies in pediatric patients. Materials and Methods: A hospital-based cross-sectional retrospective study was conducted. The study group comprised 21 pediatric patients presenting to the Departments of Radiodiagnosis and Pediatric Surgery in a tertiary care hospital from May 2011 to April 2016. All patients were initially evaluated clinically followed by MRI. Results: In our study, 21 pediatric patients were diagnosed with sacral agenesis/dysgenesis related to CRS. According to the Pang′s classification, 2 (9.5% patients were Type I, 5 (23.8% patients were Type III, 7 (33.3% patients were Type IV, and 7 (33.3% patients were of Type V CRS. Clinically, 17 (81% patients presented with urinary incontinence, 6 (28.6% with fecal incontinence, 9 patients (42.9% had poor gluteal musculatures and shallow intergluteal cleft, 7 (33.3% patients had associated subcutaneous mass over spine, and 6 (28.6% patients presented with distal leg muscle atrophy. MRI showed wedge-shaped conus termination in 5 (23.8% patients and bulbous conus termination in 3 (14.3% patients above the L1 vertebral level falling into Group 1 CRS while 7 (33.3% patients had tethered cord and 6 (28.6% patients had stretched conus falling into Group 2 CRS. Conclusion: MRI is the ideal modality for detailed evaluation of the status of the vertebra, spinal cord, intra- and extra-dural lesions and helps in early diagnosis, detailed preoperative MRI evaluation and assessing concomitant anomalies and guiding further management with early institution of treatment to maximize recovery.

  4. Tethered gravity laboratories study - The center-of-gravity management concept

    Science.gov (United States)

    Bevilacqua, Franco; Merlina, Pietro; Lorenzini, Enrico Carlo; Cosmo, Mario; Bergamaschi, Silvio

    A tether system deployed from the Space Station (SS) can provide a facility for controlling the vertical position of the system center of mass at low frequencies or in the dc mode. A review of the force field on board the SS is presented, and a classification is given of the sources of external perturbations modifying the g-field at the microgravity laboratory. This provides a set of constraints to be taken into account. A complete analysis of possible configurations (single tether system, double tether system) is performed, including design criteria, SS impacts, and configuration tradeoff. Basic results are presented from an analysis aimed at identifying the acceleration noise level transmitted to the SS when a tethered system is acted upon by environmental perturbations. Possible benefits achievable by implementing the center-of-graivty management concept are assessed on the basis of development risks and expected hardware complexity.

  5. UV-Curable Hybrid Nanocomposite Coating to Protect Tether Polymer Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA need for coatings to protect and strengthen tether materials for Momentum-exchange Electrodynamic Reboost (MXER) technology, Luminit, LLC,...

  6. Computational study of small molecule binding for both tethered and free conditions.

    Science.gov (United States)

    Ytreberg, F Marty

    2010-04-29

    Using a calix[4]arene-benzene complex as a test system, we compare the potential of mean force for when the calix[4]arene is tethered versus free. When the complex is in vacuum, our results show that the difference between tethered and free is primarily due to the entropic contribution to the potential of mean force resulting in a significant binding free energy difference of 6.6 kJ/mol. By contrast, when the complex is in water, our results suggest that there is no appreciable difference between tethered and free. This study elucidates the roles of entropy and enthalpy for this small molecule system and emphasizes the point that tethering the receptor has the potential to dramatically impact the binding properties. These findings should be taken into consideration when using calixarene molecules in nanosensor design.

  7. Materials for Advancement of MXER Tether Design (1000-549) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There exist a need to develop, identify, and classify various materials that can be used in the fabrication of electrodynamic tethers for various applications. These...

  8. Materials for advancement of MXER tether design (1000-371) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There exist a need to develop, identify, and classify various materials that can be used in the fabrication of electrodynamic tethers for various applications. These...

  9. The use of the Tethered Satellite System to perform low density aerothermodynamics studies

    Science.gov (United States)

    Carlomagno, Giovanni M.; De Luca, Luigi; Siemers, Paul M.; Wood, George M., Jr.

    1988-01-01

    The Tethered Satellite System (TSS) is a cooperative space system development activity being carried out by USA and Italy. Within TSS, the Shuttle Tethered Aerothermodynamic Research Facility (STARFAC) concept has the potential to provide access to vast portions of the upper atmosphere for the purpose of atmospheric and aerothermodynamic research. The implementation of this capability will push Tether System (TS) state of the art to its limits; the primary problems being tether/satellite drag, heating, tension control, deployment/retrieval control. In this paper parametric studies are accomplished to assess some of these problems and to delineate the tradeoffs available to missions design to meet the engineering constraints. The utilization of aerodynamic rather than spherical shapes - (TSS) - as well as elementary satellite thrusting and lift are included in the present study.

  10. Advanced Particle-in-Cell (PIC) Tools for Simulation of Electrodynamic Tether Plasma Interactions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrodynamic tethers are optimally suited for use in Low-Earth-Orbit (LEO) to generate thrust or drag maneuver satellites. LEO region is polluted with space debris...

  11. International Spinal Cord Injury

    DEFF Research Database (Denmark)

    Dvorak, M F; Itshayek, E; Fehlings, M G

    2015-01-01

    STUDY DESIGN: Survey of expert opinion, feedback and final consensus. OBJECTIVE: To describe the development and the variables included in the International Spinal Cord Injury (SCI) Spinal Interventions and Surgical Procedures Basic Data set. SETTING: International working group. METHODS......: A committee of experts was established to select and define data elements. The data set was then disseminated to the appropriate committees and organizations for comments. All suggested revisions were considered and both the International Spinal Cord Society and the American Spinal Injury Association endorsed...... the final version. RESULTS: The data set consists of nine variables: (1) Intervention/Procedure Date and start time (2) Non-surgical bed rest and external immobilization, (3) Spinal intervention-closed manipulation and/or reduction of spinal elements, (4) Surgical procedure-approach, (5) Date and time...

  12. Is early cord clamping, delayed cord clamping or cord milking best?

    Science.gov (United States)

    Vatansever, Binay; Demirel, Gamze; Ciler Eren, Elif; Erel, Ozcan; Neselioglu, Salim; Karavar, Hande Nur; Gundogdu, Semra; Ulfer, Gozde; Bahadir, Selcen; Tastekin, Ayhan

    2018-04-01

    To compare the antioxidant status of three cord clamping procedures (early clamping, delayed clamping and milking) by analyzing the thiol-disulfide balance. This randomized controlled study enrolled 189 term infants who were divided into three groups according to the cord clamping procedure: early clamping, delayed clamping and milking. Blood samples were collected from the umbilical arteries immediately after clamping, and the thiol/disulfide homeostasis was analyzed. The native and total thiol levels were significantly (p cord clamping group compared with the other two groups. The disulfide/total thiol ratio was significantly (p = .026) lower in the delayed cord clamping and milking groups compared with the early clamping groups. Early cord clamping causes the production of more disulfide bonds and lower thiol levels, indicating that oxidation reactions are increased in the early cord clamping procedure compared with the delayed cord clamping and milking procedures. The oxidant capacity is greater with early cord clamping than with delayed clamping or cord milking. Delayed cord clamping or milking are beneficial in neonatal care, and we suggest that they be performed routinely in all deliveries.

  13. The evaluation of brake mechanisms in the deployment of Electrodynamic Tether for space debris removal

    Science.gov (United States)

    2016-03-30

    increase of space debris is becoming a serious problem and active removal of large debris is required. The Japan Aerospace Exploration Agency (JAXA...mechanism, Deployment friction, Electrodynamic tether system, Space debris , Tether. Introduction The increase of space debris , which are defunct or...to exponentially increase [1] [2]. Consequently, the active removal of large space debris from crowded economically useful orbits (800-1500km alt

  14. Control by damping Injection of Electrodynamic Tether System in an Inclined Orbit

    DEFF Research Database (Denmark)

    Larsen, Martin Birkelund; Blanke, Mogens

    2009-01-01

    Control of a satellite system with an electrodynamic tether as actuator is a time-periodic and underactuated control problem. This paper considers the tethered satellite in a Hamiltonian framework and determines a port-controlled Hamiltonian formulation that adequately describes the nonlinear...... of the closed loop system is treated using Floquet theory, investigating the closed loop properties for their dependency of the controller gain and orbit inclination....

  15. Simulation of a tethered microgravity robot pair and validation on a planar air bearing

    Science.gov (United States)

    Mantellato, R.; Lorenzini, E. C.; Sternberg, D.; Roascio, D.; Saenz-Otero, A.; Zachrau, H. J.

    2017-09-01

    A software model has been developed to simulate the on-orbit dynamics of a dual-mass tethered system where one or both of the tethered spacecraft are able to produce propulsive thrust. The software simulates translations and rotations of both spacecraft, with the visco-elastic tether being simulated as a lumped-mass model. Thanks to this last feature, tether longitudinal and lateral modes of vibration and tether tension can be accurately assessed. Also, the way the spacecraft motion responds to sudden tether tension spikes can be studied in detail. The code enables the simulation of different scenarios, including space tug missions for deorbit maneuvers in a debris mitigation context and general-purpose tethered formation flight missions. This study aims to validate the software through a representative test campaign performed with the MIT Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) planar air bearing system. Results obtained with the numerical simulator are compared with data from direct measurements in different testing setups. The studied cases take into account different initial conditions of the spacecraft velocities and relative attitudes, and thrust forces. Data analysis is presented comparing the results of the simulations with direct measurements of acceleration and Azimuth rate of the two bodies in the planar air bearing test facility using a Nylon tether. Plans for conducting a microgravity test campaign using the SPHERES satellites aboard the International Space Station are also being scheduled in the near future in order to further validate the simulation using data from the relevant operational environment of extended microgravity with full six degree of freedom (per body) motion.

  16. Magnetically Tuning Tether Mobility of Integrin Ligand Regulates Adhesion, Spreading, and Differentiation of Stem Cells.

    Science.gov (United States)

    Wong, Dexter S H; Li, Jinming; Yan, Xiaohui; Wang, Ben; Li, Rui; Zhang, Li; Bian, Liming

    2017-03-08

    Cells sense and respond to the surrounding microenvironment through binding of membranous integrin to ligands such as the Arg-Gly-Asp (RGD) peptide. Previous studies show that the RGD tether properties on substrate influence cell adhesion and spreading, but few studies have reported strategies to control the tether mobility of RGD on substrate via a physical and noncontact approach. Herein, we demonstrate a novel strategy to tune the tether mobility of RGD on substrate via magnetic force. We conjugate a monolayer of RGD-bearing magnetic nanoparticles (MNPs) on a glass substrate via the flexible and coiled poly(ethylene glycol) linker of large molecular weight (PEG, average MW: 2000), and this increases the RGD tether mobility, which can be significantly reduced by applying magnetic attraction on MNPs. Our data show that high RGD tether mobility delays the early adhesion and spreading of human mesenchymal stem cells (hMSCs), leading to compromised osteogenic differentiation at later stage. In contrast, hMSCs cultured on substrate with restricted RGD tether mobility, achieved either via a shorter PEG linker (MW: 200) or magnetic force, show significantly better adhesion, spreading, and osteogenic differentiation. The control utilizing RGD-bearing nonmagnetic nanoparticles shows no such enhancing effect of magnetic field on cellular events, further supporting our conjecture of magnetic tuning of RGD tether mobility. We hypothesize that high tether mobility of RGD entails additional time and effort by the cells to fully develop traction force and mechanical feedback, thereby delaying the maturation of FAs and activation of subsequent mechanotransduction signaling. Our staining results of vinculin, a critical component of FAs, and Yes-associated protein (YAP), an important mechanosensitive transcriptional factor, support our hypothesis. We believe that our work not only sheds light on the impact of dynamic presentation of cell adhesive ligands on cellular behaviors

  17. Data Tethers: Preventing Information Leakage by Enforcing Environmental Data Access Policies

    OpenAIRE

    Fleming, Charles

    2013-01-01

    Protecting data from accidental loss or theft is crucial in today's world ofmobile computing. Data Tethers provides environmental policy control of information at the data level, rather than the file level. Data Tethers uses dynamic recompilation to add label tracking instructions to existing applications in the OpenSolaris operating system, allowing fine-grain data flow tracking in legacy applications without the need to recompile from source. We demonstrate the system's feasibility with mi...

  18. Angiomyxoma of the Umbilical Cord

    OpenAIRE

    Cheng, Hung-Pin; Hsu, Chin-Yuan; Chen, Chih-Ping; Su, Tsung-Hsien

    2006-01-01

    Objective: Angiomyxoma is a rare tumor of the umbilical cord and is associated with increased perinatal morbidity and mortality. However, the management of these pregnancies in the third trimester is not clearly defined. We present a case of an angiomyxoma of the umbilical cord diagnosed in the second trimester, and highlight the contribution of color Doppler imaging to the early diagnosis of cord anomalies. Case Report: A 29 year-old, gravida 3, para 1, woman had elevated maternal serum a...

  19. Biomimicry enhances sequential reactions of tethered glycolytic enzymes, TPI and GAPDHS.

    Science.gov (United States)

    Mukai, Chinatsu; Gao, Lizeng; Bergkvist, Magnus; Nelson, Jacquelyn L; Hinchman, Meleana M; Travis, Alexander J

    2013-01-01

    Maintaining activity of enzymes tethered to solid interfaces remains a major challenge in developing hybrid organic-inorganic devices. In nature, mammalian spermatozoa have overcome this design challenge by having glycolytic enzymes with specialized targeting domains that enable them to function while tethered to a cytoskeletal element. As a step toward designing a hybrid organic-inorganic ATP-generating system, we implemented a biomimetic site-specific immobilization strategy to tether two glycolytic enzymes representing different functional enzyme families: triose phosphoisomerase (TPI; an isomerase) and glyceraldehyde 3-phosphate dehydrogenase (GAPDHS; an oxidoreductase). We then evaluated the activities of these enzymes in comparison to when they were tethered via classical carboxyl-amine crosslinking. Both enzymes show similar surface binding regardless of immobilization method. Remarkably, specific activities for both enzymes were significantly higher when tethered using the biomimetic, site-specific immobilization approach. Using this biomimetic approach, we tethered both enzymes to a single surface and demonstrated their function in series in both forward and reverse directions. Again, the activities in series were significantly higher in both directions when the enzymes were coupled using this biomimetic approach versus carboxyl-amine binding. Our results suggest that biomimetic, site-specific immobilization can provide important functional advantages over chemically specific, but non-oriented attachment, an important strategic insight given the growing interest in recapitulating entire biological pathways on hybrid organic-inorganic devices.

  20. Biomimicry enhances sequential reactions of tethered glycolytic enzymes, TPI and GAPDHS.

    Directory of Open Access Journals (Sweden)

    Chinatsu Mukai

    Full Text Available Maintaining activity of enzymes tethered to solid interfaces remains a major challenge in developing hybrid organic-inorganic devices. In nature, mammalian spermatozoa have overcome this design challenge by having glycolytic enzymes with specialized targeting domains that enable them to function while tethered to a cytoskeletal element. As a step toward designing a hybrid organic-inorganic ATP-generating system, we implemented a biomimetic site-specific immobilization strategy to tether two glycolytic enzymes representing different functional enzyme families: triose phosphoisomerase (TPI; an isomerase and glyceraldehyde 3-phosphate dehydrogenase (GAPDHS; an oxidoreductase. We then evaluated the activities of these enzymes in comparison to when they were tethered via classical carboxyl-amine crosslinking. Both enzymes show similar surface binding regardless of immobilization method. Remarkably, specific activities for both enzymes were significantly higher when tethered using the biomimetic, site-specific immobilization approach. Using this biomimetic approach, we tethered both enzymes to a single surface and demonstrated their function in series in both forward and reverse directions. Again, the activities in series were significantly higher in both directions when the enzymes were coupled using this biomimetic approach versus carboxyl-amine binding. Our results suggest that biomimetic, site-specific immobilization can provide important functional advantages over chemically specific, but non-oriented attachment, an important strategic insight given the growing interest in recapitulating entire biological pathways on hybrid organic-inorganic devices.

  1. Study of dynamical stability of tethered systems during space tug maneuvers

    Science.gov (United States)

    Mantellato, R.; Olivieri, L.; Lorenzini, E. C.

    2017-09-01

    The dynamics of a space tether system composed of one active spacecraft, an uncontrolled large debris (e.g., a defunct satellite), and a visco-elastic tether connecting the two bodies are investigated in this paper. The active spacecraft is assumed to be equipped with a propulsive system for carrying out a tug maneuver that forces the orbital decay of the debris. The dynamical stability and the eigenfrequencies of the tethered system under the action of the thrust are investigated with both numerical and analytical models. A more complex numerical lumped-masses model provides the reference to validate the results hailing from the simplified models. Simplified models of orbital decay, tether, and debris attitude motions were derived using the Clohessy-Wiltshire equations. The results obtained with the simplified models fit very well with those from the lumped-masses model for a wide range of initial conditions. Thanks to the analytical models two resonance conditions were found, both of them affecting the attitude dynamics of the debris, that could represent a serious issue for the safety of the tug maneuver. Also, an instability mechanism that could induce the dual mass system to rotate around its center of mass under certain conditions was identified. These findings make it possible to pinpoint the set of initial conditions of the tethered system at the beginning of the thrust event that provides a dynamically stable tug maneuver for different configurations of the system (e.g., low/high thrust, stiff/elastic tethers).

  2. Tethered motion of uniflagellated bacteria at the liquid-solid surface

    Science.gov (United States)

    Bell, Jordan; Tang, Jay

    Direct evidence of the bacterial flagellar motor's rotation was first noted when multiflagellated bacterial cells were observed (under the optical microscope) to rotate when tethered to glass by a single flagellum. The tethered cell assay has continued to play a significant role throughout the subsequent studies of motor characteristics and behavior. Such studies have expanded to include uniflagellated bacteria, such as Vibrio alginolyticus, Pseudomonas aeruginosa, and Caulobacter crescentus. Here we show that such cells are not necessarily tethered by their flagellum, but rather elsewhere on the cell body. The observed cell body rotation is actually due to the flagellum either ``rolling'' against the glass surface, or pushing the cell body at the flagellar base. These motions are directly observed for Vibrio alginolyticus with darkfield microscopy. Additionally, our recently measured distributions of intervals between motor switches for tethered Caulobacter crescentus also confirm this more complicated mode of tethering. Therefore, the rotational speed of tethered uniflagellated bacteria may not equate to that of the motor itself, as is commonly assumed.

  3. Tethered Swimming for the Evaluation and Prescription of Resistance Training in Young Swimmers.

    Science.gov (United States)

    Papoti, Marcelo; da Silva, Adelino S R; Kalva-Filho, Carlos Augusto; Araujo, Gustavo Gomes; Santiago, Vanessa; Martins, LuizEduardo Barreto; Cunha, Sérgio Augusto; Gobatto, Claudio Alexandre

    2017-02-01

    The aims of the present study were 1) to evaluate the effects of 11 weeks of a typical free-swimming training program on aerobic and stroke parameters determined in tethered swimming (Study 1; n=13) and 2) to investigate the responses of tethered swimming efforts, in addition to free-swimming sessions, through 7 weeks of training (Study 2; n=21). In both studies, subjects performed a graded exercise test in tethered swimming (GET) to determine anaerobic threshold (AnT), stroke rate at AnT (SRAnT), peak force at GET (PFGET) and peak blood lactate ([La-]GET). Participants also swam 100-, 200- and 400-m lengths to evaluate performance. In Study 2, swimmers were divided into control (i. e., only free-swimming; GC [n=11]) and tethered swimming group (i. e., 50% of the main session; GTS [n=10]). The results of Study 1 demonstrate that AnT, PFGET, [La(-)]GET and 200-m performance were improved with free-swimming training. The SRAnT decreased with training. In Study 2, free-swimming performance and most of the graded exercise test parameters were not altered in either group. However, [La-]GET improved only for GTS. These results demonstrate that aerobic parameters obtained in tethered swimming can be used to evaluate free-swimming training responses, and the addition of tethered efforts during training routine improves the lactate production capacity of swimmers. © Georg Thieme Verlag KG Stuttgart · New York.

  4. AFM/TIRF force clamp measurements of neurosecretory vesicle tethers reveal characteristic unfolding steps.

    Directory of Open Access Journals (Sweden)

    Mark C Harris

    Full Text Available Although several proteins have been implicated in secretory vesicle tethering, the identity and mechanical properties of the components forming the physical vesicle-plasma membrane link remain unknown. Here we present the first experimental measurements of nanomechanical properties of secretory vesicle-plasma membrane tethers using combined AFM force clamp and TIRF microscopy on membrane sheets from PC12 cells expressing the vesicle marker ANF-eGFP. Application of pulling forces generated tether extensions composed of multiple steps with variable length. The frequency of short (<10 nm tether extension events was markedly higher when a fluorescent vesicle was present at the cantilever tip and increased in the presence of GTPγS, indicating that these events reflect specifically the properties of vesicle-plasma membrane tethers. The magnitude of the short tether extension events is consistent with extension lengths expected from progressive unfolding of individual helices of the exocyst complex, supporting its direct role in forming the physical vesicle-plasma membrane link.

  5. AFM/TIRF force clamp measurements of neurosecretory vesicle tethers reveal characteristic unfolding steps.

    Science.gov (United States)

    Harris, Mark C; Cislo, Dillon; Lenz, Joan S; Umbach, Christopher; Lindau, Manfred

    2017-01-01

    Although several proteins have been implicated in secretory vesicle tethering, the identity and mechanical properties of the components forming the physical vesicle-plasma membrane link remain unknown. Here we present the first experimental measurements of nanomechanical properties of secretory vesicle-plasma membrane tethers using combined AFM force clamp and TIRF microscopy on membrane sheets from PC12 cells expressing the vesicle marker ANF-eGFP. Application of pulling forces generated tether extensions composed of multiple steps with variable length. The frequency of short (<10 nm) tether extension events was markedly higher when a fluorescent vesicle was present at the cantilever tip and increased in the presence of GTPγS, indicating that these events reflect specifically the properties of vesicle-plasma membrane tethers. The magnitude of the short tether extension events is consistent with extension lengths expected from progressive unfolding of individual helices of the exocyst complex, supporting its direct role in forming the physical vesicle-plasma membrane link.

  6. Vocal Cord Nodules, Polyps, and Cysts

    Science.gov (United States)

    ... in three forms; nodules, polyps, and cysts. Vocal Cord Nodules (also called Singer's Nodes, Screamer's Nodes) Vocal ... when overuse of the area is stopped. Vocal Cord Polyp A vocal cord polyp typically occurs only ...

  7. Lipoproteins tethered dendrimeric nanoconstructs for effective targeting to cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Anupriya; Jain, Keerti, E-mail: keertijain02@gmail.com; Mehra, Neelesh Kumar, E-mail: neelesh81mph@gmail.com; Jain, N. K., E-mail: dr.jnarendr@gmail.com [Dr. H. S. Gour University, Pharmaceutics Research Laboratory, Department of Pharmaceutical Sciences (India)

    2013-10-15

    In the present investigation, poly (propylene imine) dendrimers up to fifth generation (PPI G5.0) were synthesized using ethylene diamine and acrylonitrile. Lipoproteins (high-density lipoprotein; HDL and low-density lipoprotein; LDL) were isolated from human plasma by discontinuous density gradient ultracentrifugation, characterized and tethered to G5.0 PPI dendrimers to construct LDL- and HDL-conjugated dendrimeric nanoconstructs for tumor-specific delivery of docetaxel. Developed formulations showed sustained release characteristics in in vitro drug release and in vivo pharmacokinetic studies. The cancer targeting potential of lipoprotein coupled dendrimers was investigated by ex vivo cytotoxicity and cell uptake studies using human hepatocellular carcinoma cell lines (HepG2 cells) and biodistribution studies in albino rats of Sprague-Dawley strain. Lipoprotein anchored dendrimeric nanoconstructs showed significant uptake by cancer cells as well as higher biodistribution of docetaxel to liver and spleen. It is concluded that these precisely synthesized engineered dendrimeric nanoconstructs could serve as promising drug carrier for fighting with the fatal disease, i.e., cancer, attributed to their defined targeting and therapeutic potential.

  8. Lipoproteins tethered dendrimeric nanoconstructs for effective targeting to cancer cells

    Science.gov (United States)

    Jain, Anupriya; Jain, Keerti; Mehra, Neelesh Kumar; Jain, N. K.

    2013-10-01

    In the present investigation, poly (propylene imine) dendrimers up to fifth generation (PPI G5.0) were synthesized using ethylene diamine and acrylonitrile. Lipoproteins (high-density lipoprotein; HDL and low-density lipoprotein; LDL) were isolated from human plasma by discontinuous density gradient ultracentrifugation, characterized and tethered to G5.0 PPI dendrimers to construct LDL- and HDL-conjugated dendrimeric nanoconstructs for tumor-specific delivery of docetaxel. Developed formulations showed sustained release characteristics in in vitro drug release and in vivo pharmacokinetic studies. The cancer targeting potential of lipoprotein coupled dendrimers was investigated by ex vivo cytotoxicity and cell uptake studies using human hepatocellular carcinoma cell lines (HepG2 cells) and biodistribution studies in albino rats of Sprague-Dawley strain. Lipoprotein anchored dendrimeric nanoconstructs showed significant uptake by cancer cells as well as higher biodistribution of docetaxel to liver and spleen. It is concluded that these precisely synthesized engineered dendrimeric nanoconstructs could serve as promising drug carrier for fighting with the fatal disease, i.e., cancer, attributed to their defined targeting and therapeutic potential.

  9. Tethered naphthalene diimide-based intercalators for DNA triplex stabilization

    Science.gov (United States)

    Gianolio, Diego A.; Segismundo, Joanna M.; McLaughlin, Larry W.

    2000-01-01

    The synthesis and triplex stabilizing properties of oligodeoxyribonucleotides functionalized at the 5′- and/or 3′-termini with a naphthalene diimide-based (NDI) intercalator is described. The NDI intercalator was prepared in a single step from the corresponding dianhydride and was attached to the 5′-terminus of an oligodeoxyribonucleotide following a reverse coupling procedure. The DMT protecting group was removed and the sequence phosphitylated to generate the phosphoramidite derivative on the 5′-terminus of the support-bound oligodeoxyribonucleotide. The NDI intercalator with a free hydroxyl was then added in the presence of tetrazole. Attachment of the NDI to the 3′-terminus relied upon a tethered amino group that could be functionalized first with the naphthalene dianhydride, which was subsequently converted to the diimide. Using both procedures, an oligonucleotide conjugate was prepared having the NDI intercalator at both the 5′- and 3′-termini. Thermal denaturation studies were used to determine the remarkable gain in stability for triplexes formed when the NDI-conjugated oligonucleotide was present as the third strand in the complex. PMID:10773082

  10. Critical adsorption of copolymer tethered on selective surfaces

    Science.gov (United States)

    Li, Hong; Qian, Chang-Ji; Luo, Meng-Bo

    2016-04-01

    Critical adsorption behaviors of flexible copolymer chains tethered to a flat homogeneous surface are studied by using Monte Carlo simulations. We have compared the critical adsorption temperature Tc, estimated by a finite-size scaling method, for different AB copolymer sequences with A the attractive monomer and B the inert monomer. We find that Tc increases with an increase in the fraction of monomers A, fA, in copolymers, and it increases with an increase in the length of block A for the same fA. In particular, Tc of copolymer (AnBn)r can be expressed as a function of the block length, n, and Tc of copolymer (AnB)r and (ABm)r can be expressed as a linear function of fA. Tc of random copolymer chains also can be expressed as a linear function of fA and it can be estimated by using weight-average of Tc of different diblocks in the random copolymer. However, the crossover exponent is roughly independent of AB sequence distributions either for block copolymers or for random copolymers.

  11. Flow structures around a beetle in a tethered flight

    Science.gov (United States)

    Lee, Boogeon; Oh, Sehyeong; Park, Hyungmin; Choi, Haecheon

    2017-11-01

    In the present study, through a wind-tunnel experiment, we visualize the flow in a tethered flight of a rhinoceros beetle using a smoke-wire visualization technique. Measurements are done at five side planes along the wind span while varying the body angle (angle between the horizontal and the body axis) to investigate the influence of the stroke plane angle that was observed to change depending on the flight mode such as hovering, forward and takeoff flights so on. Observing that a large attached leading-edge vortex is only found on the hindwing, it is inferred that most of the aerodynamic forces would be generated by hindwings (flexible inner wings) compared to the elytra (hard outer wings). In addition, it is observed to use unsteady lift-generating mechanisms such as clap-and-fling, wing-wing interaction and wake capture. Finally, we discuss the relation between the advance ratio and Strouhal number by adjusting free-stream velocity and the body angle (i.e., angle of wake-induced flow). Supported by a Grant to Bio-Mimetic Robot Research Center Funded by Defense Acquisition Program Administration, and by ADD, Korea (UD130070ID).

  12. Axillary web syndrome: nature and localization.

    Science.gov (United States)

    Leduc, O; Sichere, M; Moreau, A; Rigolet, J; Tinlot, A; Darc, S; Wilputte, F; Strapart, J; Parijs, T; Clément, A; Snoeck, T; Pastouret, F; Leduc, A

    2009-12-01

    Axillary Web Syndrome (AWS) is a complication that can arise in patients following treatment for breast cancer. It is also known variously as syndrome of the axillary cords, syndrome of the axillary adhesion, and cording lymphedema. The exact origin, presentation, course, and treatment of AWS is still largely undefined. Because so little is known about AWS, we undertook a case series study consisting of 15 women who had undergone breast cancer surgery and presented with AWS. All subjects received a clinical examination which included body size determination and detailed measurements of the size and location of the cords. The cords were found to originate from the axilla, continue on the medial aspect of the arm up to the epitrochlea region, then to the anteromedian aspect of the forearm, and finally reaching the base of the thumb. The cords averaged approximately 44% of the limb length. Correlation of the cord location with anatomical studies shows that in fact this path follows the specific course taken by the antero-radial pedicle which arises at the anterior aspect of the elbow from the brachial medial pedicule to anastomose in the axilla at the level of the lateral thoracic chain nodes. Although our series is small, the correspondence between the physical findings and the anatomical studies strongly supports the notion that the cords are lymphatic in origin.

  13. A case of duplication of 13q32-->qter and deletion of 18p11.32-->pter with mild phenotype: Patau syndrome and duplications of 13q revisited.

    Science.gov (United States)

    Helali, N; Iafolla, A K; Kahler, S G; Qumsiyeh, M B

    1996-07-01

    A mild clinical phenotype is described in a patient with duplication of 13q32-->qter and a small deletion of 18p11.32-->pter. The 8 year old white male presented with psychomotor retardation, tethered cord, soft, fleshy ears, and normal facial features except for thin lips. The karyotype was found to be 46, XY, der(18)t(13;18) (q32;p11.32) pat confirmed by fluorescence in situ hybridisation (FISH). A review of earlier studies showed that features of trisomy 13 are found in cases of duplication of bands 13q14 to qter. None of the cardinal features of trisomy 13 was seen in this patient. The absence of polydactyly, hernias, urogenital abnormalities, and haemangiomas contrast this condition with both trisomy 13 and duplication of 13q14-22-->qter. Possible explanations for lack of Patau syndrome in this patient could include restriction of the critical region for Patau syndrome to duplication 13q14-->13q32 with variable expression, gene interactions, or interchromosomal effects.

  14. Structural and functional plasticity of subcellular tethering, targeting and processing of RPGRIP1 by RPGR isoforms.

    Science.gov (United States)

    Patil, Hemangi; Guruju, Mallikarjuna R; Cho, Kyoung-In; Yi, Haiqing; Orry, Andrew; Kim, Hyesung; Ferreira, Paulo A

    2012-02-15

    Mutations affecting the retinitis pigmentosa GTPase regulator-interacting protein 1 (RPGRIP1) interactome cause syndromic retinal dystrophies. RPGRIP1 interacts with the retinitis pigmentosa GTPase regulator (RPGR) through a domain homologous to RCC1 (RHD), a nucleotide exchange factor of Ran GTPase. However, functional relationships between RPGR and RPGRIP1 and their subcellular roles are lacking. We show by molecular modeling and analyses of RPGR disease-mutations that the RPGR-interacting domain (RID) of RPGRIP1 embraces multivalently the shared RHD of RPGR(1-19) and RPGR(ORF15) isoforms and the mutations are non-overlapping with the interface found between RCC1 and Ran GTPase. RPGR disease-mutations grouped into six classes based on their structural locations and differential impairment with RPGRIP1 interaction. RPGRIP1α(1) expression alone causes its profuse self-aggregation, an effect suppressed by co-expression of either RPGR isoform before and after RPGRIP1α(1) self-aggregation ensue. RPGR(1-19) localizes to the endoplasmic reticulum, whereas RPGR(ORF15) presents cytosolic distribution and they determine uniquely the subcellular co-localization of RPGRIP1α(1). Disease mutations in RPGR(1) (-19), RPGR(ORF15), or RID of RPGRIP1α(1), singly or in combination, exert distinct effects on the subcellular targeting, co-localization or tethering of RPGRIP1α(1) with RPGR(1-19) or RPGR(ORF15) in kidney, photoreceptor and hepatocyte cell lines. Additionally, RPGR(ORF15), but not RPGR(1-19), protects the RID of RPGRIP1α(1) from limited proteolysis. These studies define RPGR- and cell-type-dependent targeting pathways with structural and functional plasticity modulating the expression of mutations in RPGR and RPGRIP1. Further, RPGR isoforms distinctively determine the subcellular targeting of RPGRIP1α(1,) with deficits in RPGR(ORF15)-dependent intracellular localization of RPGRIP1α(1) contributing to pathomechanisms shared by etiologically distinct syndromic

  15. Human Rab small GTPase- and class V myosin-mediated membrane tethering in a chemically defined reconstitution system.

    Science.gov (United States)

    Inoshita, Motoki; Mima, Joji

    2017-11-10

    Membrane tethering is a fundamental process essential for the compartmental specificity of intracellular membrane trafficking in eukaryotic cells. Rab-family small GTPases and specific sets of Rab-interacting effector proteins, including coiled-coil tethering proteins and multisubunit tethering complexes, are reported to be responsible for membrane tethering. However, whether and how these key components directly and specifically tether subcellular membranes remains enigmatic. Using chemically defined proteoliposomal systems reconstituted with purified human Rab proteins and synthetic liposomal membranes to study the molecular basis of membrane tethering, we established here that Rab-family GTPases have a highly conserved function to directly mediate membrane tethering, even in the absence of any types of Rab effectors such as the so-called tethering proteins. Moreover, we demonstrate that membrane tethering mediated by endosomal Rab11a is drastically and selectively stimulated by its cognate Rab effectors, class V myosins (Myo5A and Myo5B), in a GTP-dependent manner. Of note, Myo5A and Myo5B exclusively recognized and cooperated with the membrane-anchored form of their cognate Rab11a to support membrane tethering mediated by trans-Rab assemblies on opposing membranes. Our findings support the novel concept that Rab-family proteins provide a bona fide membrane tether to physically and specifically link two distinct lipid bilayers of subcellular membranes. They further indicate that Rab-interacting effector proteins, including class V myosins, can regulate these Rab-mediated membrane-tethering reactions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. The association between urinary continence and quality of life in paediatric patients with spina bifida and tethered cord

    Science.gov (United States)

    Olesen, Jamie D; Kiddoo, Darcie A; Metcalfe, Peter D

    2013-01-01

    OBJECTIVE: To determine the association between urinary continence and quality of life (QoL) in a paediatric spina bifida population. METHODS: After appropriate ethics approval, a prospective study was initiated using multiple validated QoL instruments that were distributed to patients as they presented for their annual appointment at the Northern Alberta Spina Bifida Clinic (Edmonton, Alberta). General demographic information was collected and validated questionnaires were used. The survey package included two instruments to assess overall QoL: Global Pediatric QoL (PedsQL 4.0) and Health Specific QoL-Spina Bifida (HRQoL-SB). Two instruments were also included to quantify urinary symptoms and assess urinary specific QoL: the Urinary Incontinence Severity Index – Pediatric (ISI-P) and Urinary Specific QoL (PinQ). RESULTS: A total of 71 patients were enrolled in the study. The general QoL (PedsQL 4.0) and health-specific QoL (HRQoL-SB) scores for the population indicated an overall QoL of 66% (n=69) and 83% (n=67), respectively. Approximately 46% (33 of 71) reported >1 episode of urinary incontinence per week. Urinary continence was associated with a significantly higher urinary-specific QoL (PinQ; Pspina bifida is related to urinary continence. This effect appears to be independent of the type and level of the spinal dysraphism and the presence or absence of a shunt. PMID:24421717

  17. Pregnancy Complications: Umbilical Cord Abnormalities

    Science.gov (United States)

    ... The baby is in a breech (foot-first) position. The woman is in preterm labor . The umbilical cord is too long. There ... The baby is in a breech (foot-first) position. The woman is in preterm labor . The umbilical cord is too long. There ...

  18. Cutting the Cord-2

    Science.gov (United States)

    2004-01-01

    This animation shows the view from the rear hazard avoidance cameras on the Mars Exploration Rover Spirit as the rover turns 45 degrees clockwise. This maneuver is the first step in a 3-point turn that will rotate the rover 115 degrees to face west. The rover must make this turn before rolling off the lander because airbags are blocking it from exiting from the front lander petal. Before this crucial turn took place, engineers instructed the rover to cut the final cord linking it to the lander. The turn took around 30 minutes to complete.

  19. Cutting the Cord

    Science.gov (United States)

    2004-01-01

    This animation shows the view from the front hazard avoidance cameras on the Mars Exploration Rover Spirit as the rover turns 45 degrees clockwise. This maneuver is the first step in a 3-point turn that will rotate the rover 115 degrees to face west. The rover must make this turn before rolling off the lander because airbags are blocking it from exiting off the front lander petal. Before this crucial turn could take place, engineers instructed the rover to cut the final cord linking it to the lander. The turn took around 30 minutes to complete.

  20. Spinal Cord Injury

    Science.gov (United States)

    ... Page Diabetic Neuropathy Information Page Dysgraphia Information Page Dyslexia Information Page Dystonias Information Page Empty Sella Syndrome ... Spotlight Find NINDS Clinical Trials Patient & Caregiver Education Fact Sheets Hope Through Research Know Your Brain Preventing ...

  1. Retraining the injured spinal cord

    Science.gov (United States)

    Edgerton, V. R.; Leon, R. D.; Harkema, S. J.; Hodgson, J. A.; London, N.; Reinkensmeyer, D. J.; Roy, R. R.; Talmadge, R. J.; Tillakaratne, N. J.; Timoszyk, W.; hide

    2001-01-01

    The present review presents a series of concepts that may be useful in developing rehabilitative strategies to enhance recovery of posture and locomotion following spinal cord injury. First, the loss of supraspinal input results in a marked change in the functional efficacy of the remaining synapses and neurons of intraspinal and peripheral afferent (dorsal root ganglion) origin. Second, following a complete transection the lumbrosacral spinal cord can recover greater levels of motor performance if it has been exposed to the afferent and intraspinal activation patterns that are associated with standing and stepping. Third, the spinal cord can more readily reacquire the ability to stand and step following spinal cord transection with repetitive exposure to standing and stepping. Fourth, robotic assistive devices can be used to guide the kinematics of the limbs and thus expose the spinal cord to the new normal activity patterns associated with a particular motor task following spinal cord injury. In addition, such robotic assistive devices can provide immediate quantification of the limb kinematics. Fifth, the behavioural and physiological effects of spinal cord transection are reflected in adaptations in most, if not all, neurotransmitter systems in the lumbosacral spinal cord. Evidence is presented that both the GABAergic and glycinergic inhibitory systems are up-regulated following complete spinal cord transection and that step training results in some aspects of these transmitter systems being down-regulated towards control levels. These concepts and observations demonstrate that (a) the spinal cord can interpret complex afferent information and generate the appropriate motor task; and (b) motor ability can be defined to a large degree by training.

  2. Neurogenic bladder in Hunter's syndrome.

    Science.gov (United States)

    Koyama, K; Moda, Y; Sone, A; Tanaka, H; Hino, Y

    1994-01-01

    We encountered a rare patient with Hunter's syndrome who exhibited urinary retention as a result of a neurogenic bladder, uninhibited detrusor contractions, and detrusor-sphincter dyssynergia. Neurological findings were consistent with cervical myelopathy and cervical MR imaging showed very narrow segments at the cord level C2-4. We speculate that this Hunter's syndrome patient has cervical myelopathy and that this neurological dysfunction causes the neurogenic bladder. PMID:8014981

  3. Thrust Control During Towing of Space Debris using an Elastic Tether

    Directory of Open Access Journals (Sweden)

    A. D. Ledkov

    2014-01-01

    Full Text Available The paper considers a maneuver for deorbiting the large space debris using an active spacecraft connected with the debris by an elastic tether. Tether slacking during the maneuver can lead to the tether rupture, kinking, and winding on the descending object. Therefore it is important to prevent slacking. The objective of this work is to find the law of thrust force control of the active spacecraft to ensure a continuously strained tether during the maneuver.Using Lagrange formalism a mathematical model to describe the system plane motion is developed. This model considers the active spacecraft as a mass point, the space debris as a rigid body, and the tether as a weightless elastic rod. A thrust force is directed along the local horizon of the spacecraft. Linearization of nonlinear differential equation describing longitudinal oscillations of the tether length is performed. Its phase portrait is analyzed. An approximate expression describing the position of the center on the phase portrait is obtained. A time-optimal control with full feedback to ensure that the tether is in the strained state is found by solving the Bellman equation. To use the obtained optimal law it is necessary to set the measuring equipment on the spacecraft, which is capable of accurate measuring a distance to the space debris and its relative velocity. An alternative control law, which is simpler in terms of the practical implementation, is proposed. As an example, the descent from an orbit of nonfunctioning Soviet satellite Meteor-2 is considered. It is shown that both proposed laws provide continuous strain of the tether during deorbiting of the satellite. Moreover, slack does not occur even at the first period of oscillation of the tether length. It is shown that the use of the proposed control laws leads to slight increase of deorbiting time as compared to the case of using the constant thrust.The results can be used to develop the control systems of small spacecrafts

  4. The shear flow processing of controlled DNA tethering and stretching for organic molecular electronics.

    Science.gov (United States)

    Yu, Guihua; Kushwaha, Amit; Lee, Jungkyu K; Shaqfeh, Eric S G; Bao, Zhenan

    2011-01-25

    DNA has been recently explored as a powerful tool for developing molecular scaffolds for making reproducible and reliable metal contacts to single organic semiconducting molecules. A critical step in the process of exploiting DNA-organic molecule-DNA (DOD) array structures is the controlled tethering and stretching of DNA molecules. Here we report the development of reproducible surface chemistry for tethering DNA molecules at tunable density and demonstrate shear flow processing as a rationally controlled approach for stretching/aligning DNA molecules of various lengths. Through enzymatic cleavage of λ-phage DNA to yield a series of DNA chains of various lengths from 17.3 μm down to 4.2 μm, we have investigated the flow/extension behavior of these tethered DNA molecules under different flow strengths in the flow-gradient plane. We compared Brownian dynamic simulations for the flow dynamics of tethered λ-DNA in shear, and found our flow-gradient plane experimental results matched well with our bead-spring simulations. The shear flow processing demonstrated in our studies represents a controllable approach for tethering and stretching DNA molecules of various lengths. Together with further metallization of DNA chains within DOD structures, this bottom-up approach can potentially enable efficient and reliable fabrication of large-scale nanoelectronic devices based on single organic molecules, therefore opening opportunities in both fundamental understanding of charge transport at the single molecular level and many exciting applications for ever-shrinking molecular circuits.

  5. Shuttle tethered operations: The effect on orbital trajectory and inertial navigation

    Science.gov (United States)

    Lardas, Mark N.

    1989-01-01

    The first full scale test of a large tethered satellite system is planned. The Orbiter will be linked to a 500 kg payload by a 20 km tether, an action with a profound effect on the trajectory of the Orbiter. For the first time in the history of the Shuttle program, the vehicle will conduct prolonged operations with the center of mass of the orbiting system a significant distance from the center of mass of the Space Shuttle Orbiter, a violation of the fundamental assumption made in both the Orbiter ground-based and onboard navigation software. Inertial navigation of tethered operations with the Shuttle is further complicated by the presence of non-conservative forces in the system: Reaction Control System (RCS) translational effects, atmospheric drag, and electro-magnetic dynamics. These can couple with the conservative tether dynamics effects, and degrade the navigation software performance. The primary effects are examined on the Orbiter's trajectory, coupling by conservative forces during tethered operations, and the impact of both on the ability to meet inertial navigation constraints. The impact of electrodynamics, different RCS control modes, commanded attitudes, and attitude deadbands are presented. Operational guidelines which optimize successful mission navigation, and necessary navigation constraints are discussed.

  6. Determination of a quantitative parameter to evaluate swimming technique based on the maximal tethered swimming test.

    Science.gov (United States)

    Soncin, Rafael; Mezêncio, Bruno; Ferreira, Jacielle Carolina; Rodrigues, Sara Andrade; Huebner, Rudolf; Serrão, Julio Cerca; Szmuchrowski, Leszek

    2017-06-01

    The aim of this study was to propose a new force parameter, associated with swimmers' technique and performance. Twelve swimmers performed five repetitions of 25 m sprint crawl and a tethered swimming test with maximal effort. The parameters calculated were: the mean swimming velocity for crawl sprint, the mean propulsive force of the tethered swimming test as well as an oscillation parameter calculated from force fluctuation. The oscillation parameter evaluates the force variation around the mean force during the tethered test as a measure of swimming technique. Two parameters showed significant correlations with swimming velocity: the mean force during the tethered swimming (r = 0.85) and the product of the mean force square root and the oscillation (r = 0.86). However, the intercept coefficient was significantly different from zero only for the mean force, suggesting that although the correlation coefficient of the parameters was similar, part of the mean velocity magnitude that was not associated with the mean force was associated with the product of the mean force square root and the oscillation. Thus, force fluctuation during tethered swimming can be used as a quantitative index of swimmers' technique.

  7. Optimal Trajectory Planning and Coordinated Tracking Control Method of Tethered Space Robot Based on Velocity Impulse

    Directory of Open Access Journals (Sweden)

    Panfeng Huang

    2014-09-01

    Full Text Available The tethered space robot (TSR is a new concept of space robot which consists of a robot platform, space tether and operation robot. This paper presents a multi-objective optimal trajectory planning and a coordinated tracking control scheme for TSR based on velocity impulse in the approaching phase. Both total velocity impulse and flight time are included in this optimization. The non-dominated sorting genetic algorithm is employed to obtain the optimal trajectory Pareto solution using the TSR dynamic model and optimal trajectory planning model. The coordinated tracking control scheme utilizes optimal velocity impulse. Furthermore, the PID controller is designed in order to compensate for the distance measurement errors. The PID control force is optimized and distributed to thrusters and the space tether using a simulated annealing algorithm. The attitude interferential torque of the space tether is compensated a using time-delay algorithm through reaction wheels. The simulation results show that the multi-objective optimal trajectory planning method can reveal the relationships among flight time, fuel consumption, planar view angle and velocity impulse number. This method can provide a series of optimal trajectory according to a number of special tasks. The coordinated control scheme can significantly save thruster fuel for tracking the optimal trajectory, restrain the attitude interferential torque produced by space tether and maintain the relative attitude stability of the operation robot.

  8. Myo1c binding to submembrane actin mediates insulin-induced tethering of GLUT4 vesicles

    Science.gov (United States)

    Boguslavsky, Shlomit; Chiu, Tim; Foley, Kevin P.; Osorio-Fuentealba, Cesar; Antonescu, Costin N.; Bayer, K. Ulrich; Bilan, Philip J.; Klip, Amira

    2012-01-01

    GLUT4-containing vesicles cycle between the plasma membrane and intracellular compartments. Insulin promotes GLUT4 exocytosis by regulating GLUT4 vesicle arrival at the cell periphery and its subsequent tethering, docking, and fusion with the plasma membrane. The molecular machinery involved in GLUT4 vesicle tethering is unknown. We show here that Myo1c, an actin-based motor protein that associates with membranes and actin filaments, is required for insulin-induced vesicle tethering in muscle cells. Myo1c was found to associate with both mobile and tethered GLUT4 vesicles and to be required for vesicle capture in the total internal reflection fluorescence (TIRF) zone beneath the plasma membrane. Myo1c knockdown or overexpression of an actin binding–deficient Myo1c mutant abolished insulin-induced vesicle immobilization, increased GLUT4 vesicle velocity in the TIRF zone, and prevented their externalization. Conversely, Myo1c overexpression immobilized GLUT4 vesicles in the TIRF zone and promoted insulin-induced GLUT4 exposure to the extracellular milieu. Myo1c also contributed to insulin-dependent actin filament remodeling. Thus we propose that interaction of vesicular Myo1c with cortical actin filaments is required for insulin-mediated tethering of GLUT4 vesicles and for efficient GLUT4 surface delivery in muscle cells. PMID:22918957

  9. Attitudes Towards Individuals with Spinal Cord Injuries

    Science.gov (United States)

    Conway, Cassandra Sligh D.; Gooden, Randy; Nowell, Jennifer; Wilson, Navodda

    2010-01-01

    This paper will shed light on the lives of persons with spinal cord injuries by revealing the literature on spinal cord injuries that focuses on research that can shed light on attitudes towards persons with spinal cord injuries. The background literature related to incidences, the definition of spinal cord injury, and vocational opportunities are…

  10. Back pain: a real target for spinal cord stimulation?

    Science.gov (United States)

    Rigoard, Philippe; Delmotte, Alexandre; D'Houtaud, Samuel; Misbert, Lorraine; Diallo, Bakari; Roy-Moreau, Aline; Durand, Sylvain; Royoux, Solène; Giot, Jean-Philippe; Bataille, Benoit

    2012-03-01

    Failed back surgery syndrome represents one of the most frequent etiologies of chronic back pain and is a major public health issue. Neurostimulation has currently not been validated in the treatment of back pain because of technological limitations in implantable spinal cord stimulation (SCS) systems. New-generation leads using several columns of stimulation can generate longitudinal and/or transverse stimulation fields into the spinal cord. To investigate, through extensive stimulation testing, the capacity of multicolumn tripolar leads to achieve back territory paresthesia coverage in refractory failed back surgery syndrome patients. Eleven patients implanted with a 16-contact spinal cord stimulation lead (Specify 5-6-5, Medtronic Inc) were assessed with a systematic exploration of 43 selected stimulation configurations to generate bilateral back paresthesia in addition to leg territory coverage. The tripolar lead successfully generated paresthesia in both bilateral back and leg territories in 9 patients (81.8%). Success rates of multicolumn stimulation patterns were significantly higher than for longitudinal configurations for lombodorsal paresthesia coverage. Six months after implantation, significant pain relief was obtained compared with preoperative evaluation for global pain (Visual Analog Scale, 2.25 vs 8.2 preoperatively; P < .05), leg pain (Visual Analog Scale, 0.5 vs 7.6 preoperatively; P < .05), and back pain (Visual Analog Scale, 1.5 vs 7.8 preoperatively; P < .05). These results suggest that multicolumn leads can reliably generate back pain coverage and favor pain relief outcomes. This may lead physicians to reconsider new indications for spinal cord stimulation. Expanding neurostimulation perspectives to intractable back pain syndromes could become realistic in the near future.

  11. The HOPS/class C Vps complex tethers membranes by binding to one Rab GTPase in each apposed membrane.

    Science.gov (United States)

    Ho, Ruoya; Stroupe, Christopher

    2015-07-15

    Many Rab GTPase effectors are membrane-tethering factors, that is, they physically link two apposed membranes before intracellular membrane fusion. In this study, we investigate the distinct binding factors needed on apposed membranes for Rab effector-dependent tethering. We show that the homotypic fusion and protein-sorting/class C vacuole protein-sorting (HOPS/class C Vps) complex can tether low-curvature membranes, that is, liposomes with a diameter of ∼100 nm, only when the yeast vacuolar Rab GTPase Ypt7p is present in both tethered membranes. When HOPS is phosphorylated by the vacuolar casein kinase I, Yck3p, tethering only takes place when GTP-bound Ypt7p is present in both tethered membranes. When HOPS is not phosphorylated, however, its tethering activity shows little specificity for the nucleotide-binding state of Ypt7p. These results suggest a model for HOPS-mediated tethering in which HOPS tethers membranes by binding to Ypt7p in each of the two tethered membranes. Moreover, because vacuole-associated HOPS is presumably phosphorylated by Yck3p, our results suggest that nucleotide exchange of Ypt7p on multivesicular bodies (MVBs)/late endosomes must take place before HOPS can mediate tethering at vacuoles. © 2015 Ho and Stroupe. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  12. A Brain–Spinal Interface Alleviating Gait Deficits after Spinal Cord Injury in Primates

    Science.gov (United States)

    Capogrosso, Marco; Milekovic, Tomislav; Borton, David; Wagner, Fabien; Moraud, Eduardo Martin; Mignardot, Jean-Baptiste; Buse, Nicolas; Gandar, Jerome; Barraud, Quentin; Xing, David; Rey, Elodie; Duis, Simone; Jianzhong, Yang; Ko, Wai Kin D.; Li, Qin; Detemple, Peter; Denison, Tim; Micera, Silvestro; Bezard, Erwan; Bloch, Jocelyne; Courtine, Grégoire

    2016-01-01

    Spinal cord injury disrupts the communication between the brain and the spinal circuits that orchestrate movement. To bypass the lesion, brain–computer interfaces1–3 have directly linked cortical activity to electrical stimulation of muscles, which have restored grasping abilities after hand paralysis1,4. Theoretically, this strategy could also restore control over leg muscle activity for walking5. However, replicating the complex sequence of individual muscle activation patterns underlying natural and adaptive locomotor movements poses formidable conceptual and technological challenges6,7. Recently, we showed in rats that epidural electrical stimulation of the lumbar spinal cord can reproduce the natural activation of synergistic muscle groups producing locomotion8–10. Here, we interfaced leg motor cortex activity with epidural electrical stimulation protocols to establish a brain–spinal interface that alleviated gait deficits after a spinal cord injury in nonhuman primates. Rhesus monkeys were implanted with an intracortical microelectrode array into the leg area of motor cortex; and a spinal cord stimulation system composed of a spatially selective epidural implant and a pulse generator with real-time triggering capabilities. We designed and implemented wireless control systems that linked online neural decoding of extension and flexion motor states with stimulation protocols promoting these movements. These systems allowed the monkeys to behave freely without any restrictions or constraining tethered electronics. After validation of the brain–spinal interface in intact monkeys, we performed a unilateral corticospinal tract lesion at the thoracic level. As early as six days post-injury and without prior training of the monkeys, the brain–spinal interface restored weight-bearing locomotion of the paralyzed leg on a treadmill and overground. The implantable components integrated in the brain–spinal interface have all been approved for investigational

  13. Is repair of the protruded meninges sufficient for treatment of meningocele?

    Science.gov (United States)

    Yun-Hai, Song; Nan, Bao; Ping-Ping, Gao; Bo, Yang; Cheng, Chen

    2015-11-01

    The present study aimed to investigate the relationship between meningocele and tethered cord syndrome, diagnosis of meningocele associated with tethered cord syndrome, and when to perform surgery and the best surgical procedure. Sixty-nine children with meningocele who were admitted to Shanghai Children's Medical Center were analyzed. The relationship between meningocele and other lesions causing tethered cord syndrome was studied by combining magnetic resonance imaging (MRI) and intraoperative findings. The MRI results and intraoperative findings showed that 67 children (97%) had associated lesions such as tight filum terminale, fibrous band tethering, spinal cord or cauda equina adhesion, diastematomyelia, arachnoid cyst, and epidermoid cyst. The protruded meninges were repaired, and the intraspinal lesions were treated at the same time. Also, the tethered spinal cord was released. No neurological injuries were observed after surgery. The rate of meningocele associated with tethered cord syndrome is very high. MRI is necessary for the diagnosis of meningocele. Active surgical treatment is recommended immediately after definite diagnosis. During surgery, the surgeon should not only repair the protruded meninges but also explore the spinal canal and release the tethered cord.

  14. Diamond surface functionalization with biomimicry – Amine surface tether and thiol moiety for electrochemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sund, James B., E-mail: jim@jamessund.com [Department of Electrical and Computer Engineering, Duke University, Durham, NC (United States); Causey, Corey P. [Departments of Chemistry and Biochemistry, Duke University, Durham, NC (United States); Wolter, Scott D. [Department of Physics, Elon University, Elon, NC 27244 (United States); Parker, Charles B., E-mail: charles.parker@duke.edu [Department of Electrical and Computer Engineering, Duke University, Durham, NC (United States); Stoner, Brian R. [Department of Electrical and Computer Engineering, Duke University, Durham, NC (United States); Research Triangle Institute (RTI) International, Research Triangle Park, NC (United States); Toone, Eric J. [Departments of Chemistry and Biochemistry, Duke University, Durham, NC (United States); Glass, Jeffrey T. [Department of Electrical and Computer Engineering, Duke University, Durham, NC (United States)

    2014-05-01

    Highlights: • Diamond surfaces were functionalized with organic molecules using a novel approach. • Used biomimicry to select a molecule to bind NO, similar to the human body. • Molecular orbital theory predicted the molecule-analyte oxidation behavior. • A thiol moiety was attached to an amine surface tether on the diamond surface. • XPS analysis verified each surface functionalization step. - Abstract: The surface of conducting diamond was functionalized with a terminal thiol group that is capable of binding and detecting nitrogen–oxygen species. The functionalization process employed multiple steps starting with doped diamond films grown by plasma enhanced chemical vapor deposition followed by hydrogen termination and photochemical attachment of a chemically protected amine alkene. The surface tether was deprotected to reveal the amine functionality, which enabled the tether to be extended with surface chemistry to add a terminal thiol moiety for electrochemical sensing applications. Each step of the process was validated using X-ray photoelectron spectroscopy analysis.

  15. Modeling and Control of Electrodynamic Tethers - an Energy and Topology Approach

    DEFF Research Database (Denmark)

    Larsen, Martin Birkelund

    , and separate derivations of the dynamical equations can be cumbersome. It can therefore be advantageous to be able to model a formation independent of its topology, i.e. the way tethers and satellites are interconnected. The thesis treats a class of formations in a generic framework, using graph theory......-flying spacecrafts, since a predetermined geometry of spacecrafts is easily maintained. This thesis investigates the use of electrodynamic tethers for such tethered satellite formaii tions with focus on the modeling and control aspects. One can think of many different structures for solving tasks in space...... to describe the topology of the formations. The framework can be used both to deduce the equations of motion for the attitude motion of the formation and for control design regarding the same motion. The main part of the thesis consists of five scientific papers which have been submitted for international...

  16. Low density aerothermodynamics studies performed by means of the tethered satellite system

    Science.gov (United States)

    Carlomagno, Giovanni M.; De Luca, Luigi; Siemers, Paul M.; Wood, George M., Jr.

    1986-01-01

    Low density gas flow modeling and current ground wind-tunnel technologies are not presently able to produce fully reliable data concerning low density flow regimes. In order to answer some of these issues, the Shuttle Continuous Open Wind Tunnel (SCOWT) program has been proposed, which makes use of the tethered satellite system (TSS). SCOWT's objective is to investigate the energy and momentum transfer between the tethered satellite and its environmental medium within the range of the thermofluid-dynamic conditions experienced by TSS during its atmospheric flights. The feasibility and capability of SCOWT to perform low density aerothermodynamics studies are investigated. Some of the results, obtained by means of a tether simulation program, and the instrumentation and TSS design main requirements to meet SCOWT objectives are described.

  17. Self-Assembled Array of Tethered Manganese Oxide Nanoparticles for the Next Generation of Energy Storage

    Science.gov (United States)

    Stevens, Tyler E.; Pearce, Charles J.; Whitten, Caleah N.; Grant, Richard P.; Monson, Todd C.

    2017-03-01

    Many challenges must be overcome in order to create reliable electrochemical energy storage devices with not only high energy but also high power densities. Gaps exist in both battery and supercapacitor technologies, with neither one satisfying the need for both large power and energy densities in a single device. To begin addressing these challenges (and others), we report a process to create a self-assembled array of electrochemically active nanoparticles bound directly to a current collector using extremely short (2 nm or less) conductive tethers. The tethered array of nanoparticles, MnO in this case, bound directly to a gold current collector via short conducting linkages eliminates the need for fillers, resulting in a material which achieves 99.9% active material by mass (excluding the current collector). This strategy is expected to be both scalable as well as effective for alternative tethers and metal oxide nanoparticles.

  18. Spinal cord toxoplasmosis in AIDS; Toxoplasmose medullaire et sida

    Energy Technology Data Exchange (ETDEWEB)

    Carteret, M.; Petit, E.; Granat, O.; Marichez, M.; Gilquin, J. [Hopital Saint-Joseph, 69 - Lyon (France)

    1995-07-01

    Toxoplasmosis is the most common brain parasitic infection in acquired immunodeficiency syndrome (AIDS). Spinal cord localizations are still rare (2 cases with cerebral involvement, 2 cases without). A case of both spinal cord and cerebral involvement is reported. Magnetic resonance imaging (MR imaging) was performed because of sensory level (L 1). A focal conus medullaris enlargement was seen, iso intense on T 1 weighted images. This lesion was hyperintense on T 2 weighted sequence, and was homogeneously enhanced after Gadolinium on T 1 weighted images. A medullary oedema was noted. A toxoplasmosis treatment was initiated, without cortico therapy. MR imaging performed one month later (D 30), while important clinical improvements were seen, pointed out normal thickness of conus medullaris, without enhancement after Gadolinium. Disease lesions in AIDS with focal spinal cord processes are reviewed, and diagnostic work-up is discussed. Spinal cord single lesion, associated or not with brain involvements should be treated as a toxoplasmic infection, with MR imaging follow up. This work up should avoid medullary biopsy, still required in case of treatment failure. Cerebral involvements, with multiples lesions can mask medullary localization. (authors). 8 refs., 2 figs.

  19. Unilateral pedicle screws asymmetric tethering: an innovative method to create idiopathic deformity

    Directory of Open Access Journals (Sweden)

    Zhang Xuesong

    2007-10-01

    Full Text Available Abstract Objective To evaluate the feasibility of the method that unilateral pedicle screws asymmetric tethering in concave side in combination with convex rib resection for creating idiopathic deformity. Summary of background data Various methods are performed to create idiopathic deformity. Among these methods, posterior asmmetric tethering of the spine shows satisfying result, but some drawbacks related to the current posterior asymmetric tether were still evident. Materials and methods Unilateral pedicle screws asymmetric tethering was performed to 14 female goats (age: 5–8 week-old, weight: 6–8 kg in concave side in combination with convex rib resection. Dorsoventral and lateral plain radiographs were taken of each thoracic spine in the frontal and sagittal planes right after the surgery and later every 4 weeks. Results All animals ambulated freely after surgery. For technical reasons, 2 goats were excluded (one animal died for anesthetic during the surgery, and one animal was lost for instrumental fail due to postoperative infection. Radiography showed that 11 goats exhibited scoliosis with convex toward to the right side, and as the curve increased with time, only 1 goat showed nonprogressive. The initial scoliosis generated in the progressors after the procedures measured 29.0° on average (range 23.0°–38.5° and increased to 43.0° on average (range 36.0°–58.0° over 8 to 10 weeks. The average progression of 14.0° was measured. The curvature immediately after tethering surgery (the initial Cobb angle did have a highly significant correlation with the final curvature (p Conclusion Unilateral pedicle screws asymmetric tethering is a practical method to create experimental scoliosis, especially for those who would like to study the correction of this deformity.

  20. Differential regulation of synaptic vesicle tethering and docking by UNC-18 and TOM-1

    Directory of Open Access Journals (Sweden)

    Elena O Gracheva

    2010-10-01

    Full Text Available The assembly of SNARE complexes between syntaxin, SNAP-25 and synaptobrevin is required to prime synaptic vesicles for fusion. Since Munc18 and tomosyn compete for syntaxin interactions, the interplay between these proteins is predicted to be important in regulating synaptic transmission. We explored this possibility, by examining genetic interactions between C. elegans unc-18(Munc18, unc-64(syntaxin and tom-1(tomosyn. We have previously demonstrated that unc-18 mutants have reduced synaptic transmission, whereas tom-1 mutants exhibit enhanced release. Here we show that the unc-18 mutant release defect is associated with loss of two morphologically distinct vesicle pools; those tethered within 25nm of the plasma membrane and those docked with the plasma membrane. In contrast, priming defective unc-13 mutants accumulate tethered vesicles, while docked vesicles are greatly reduced, indicating tethering is UNC-18-dependent and occurs in the absence of priming. C. elegans unc-64 mutants phenocopy unc-18 mutants, losing both tethered and docked vesicles, whereas overexpression of open syntaxin preferentially increases vesicle docking, suggesting UNC-18/closed syntaxin interactions are responsible for vesicle tethering. Given the competition between vertebrate tomosyn and Munc18, for syntaxin binding, we hypothesized that C. elegans TOM-1 may inhibit both UNC-18-dependent vesicle targeting steps. Consistent with this hypothesis, tom-1 mutants exhibit enhanced UNC-18 plasma membrane localization and a concomitant increase in both tethered and docked synaptic vesicles. Furthermore, in tom-1;unc-18 double mutants the docked, primed vesicle pool is preferentially rescued relative to unc-18 single mutants. Together these data provide evidence for the differential regulation of two vesicle targeting steps by UNC-18 and TOM-1 through competitive interactions with syntaxin

  1. The Disulfide Bonds within BST-2 Enhance Tensile Strength during Viral Tethering.

    Science.gov (United States)

    Du Pont, Kelly E; McKenzie, Aidan M; Kokhan, Oleksandr; Sumner, Isaiah; Berndsen, Christopher E

    2016-02-16

    Human BST-2/tetherin is a host factor that inhibits the release of enveloped viruses, including HIV-1, HIV-2, and SIV, from the cell surface by tethering viruses to the host cell membrane. BST-2 has an α-helical ectodomain that forms disulfide-linked dimers between two monomers forming a coiled coil. The ectodomain contains three cysteine residues that can participate in disulfide bond formation and are critical for viral tethering. The role of the disulfides in viral tethering is unknown but proposed to be for maintaining the dimer. We explored the role of the disulfides in the structure of BST-2 using experimental, biophysical methods. To understand the role of the disulfides in viral tethering, we used a new approach in viral tethering, steered molecular dynamics. We find that the disulfides coordinate the unfolding of the BST-2 monomers, which adds tensile strength to the coiled coil. Structural differences between oxidized and reduced BST-2 are apparent during unfolding, showing the monomers slide past each other in the absence of the disulfides. We found no evidence to support dissociation of the dimer upon reduction of the disulfide bonds. Moreover, the structure of BST-2 in the absence of the disulfides is similar to that of the oxidized form of BST-2, supporting previous X-ray crystallography and cellular work that showed the disulfides are not required for expression of BST-2. These data provide new insights into viral tethering by using novel techniques in the analysis of BST-2 to give amino acid level insight into functions of BST-2.

  2. Conserved TCP domain of Sas-4/CPAP is essential for pericentriolar material tethering during centrosome biogenesis

    Science.gov (United States)

    Zheng, Xiangdong; Gooi, Li Ming; Wason, Arpit; Gabriel, Elke; Mehrjardi, Narges Zare; Yang, Qian; Zhang, Xingrun; Debec, Alain; Basiri, Marcus L.; Avidor-Reiss, Tomer; Pozniakovsky, Andrei; Poser, Ina; Šarić, Tomo; Hyman, Anthony A.; Li, Haitao; Gopalakrishnan, Jay

    2014-01-01

    Pericentriolar material (PCM) recruitment to centrioles forms a key step in centrosome biogenesis. Deregulation of this process leads to centrosome aberrations causing disorders, one of which is autosomal recessive primary microcephaly (MCPH), a neurodevelopmental disorder where brain size is reduced. During PCM recruitment, the conserved centrosomal protein Sas-4/CPAP/MCPH6, known to play a role in centriole formation, acts as a scaffold for cytoplasmic PCM complexes to bind and then tethers them to centrioles to form functional centrosomes. To understand Sas-4’s tethering role, we determined the crystal structure of its T complex protein 10 (TCP) domain displaying a solvent-exposed single-layer of β-sheets fold. This unique feature of the TCP domain suggests that it could provide an “extended surface-like” platform to tether the Sas-4–PCM scaffold to a centriole. Functional studies in Drosophila, human cells, and human induced pluripotent stem cell-derived neural progenitor cells were used to test this hypothesis, where point mutations within the 9–10th β-strands (β9–10 mutants including a MCPH-associated mutation) perturbed PCM tethering while allowing Sas-4/CPAP to scaffold cytoplasmic PCM complexes. Specifically, the Sas-4 β9–10 mutants displayed perturbed interactions with Ana2, a centrosome duplication factor, and Bld-10, a centriole microtubule-binding protein, suggesting a role for the β9–10 surface in mediating protein–protein interactions for efficient Sas-4–PCM scaffold centriole tethering. Hence, we provide possible insights into how centrosomal protein defects result in human MCPH and how Sas-4 proteins act as a vehicle to tether PCM complexes to centrioles independent of its well-known role in centriole duplication. PMID:24385583

  3. Comparison of unrelated cord blood and peripheral blood stem cell transplantation in adults with myelodysplastic syndrome after reduced-intensity conditioning regimen: a collaborative study from Eurocord (Cord blood Committee of Cellular Therapy & Immunobiology Working Party of EBMT) and Chronic Malignancies Working Party

    NARCIS (Netherlands)

    Robin, M.; Ruggeri, A.; Labopin, M.; Niederwieser, D.; Tabrizi, R.; Sanz, G.; Bourhis, J.H.; Biezen, A. van; Koenecke, C.; Blaise, D.; Tischer, J.; Craddock, C.; Maillard, N.; Mohty, M.; Russel, N.; Schetelig, J.; Finke, J.; Gluckman, E.; Witte, T.J. de; Rocha, V.; Kroger, N.

    2015-01-01

    Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment in patients with higher risk myelodysplastic syndrome (MDS), but the choice of the optimal alternative stem cell source is still a subject of debate in patients lacking an HLA-matched sibling donor. Here, we report on

  4. Carpal tunnel syndrome in spinal patients

    OpenAIRE

    Zmeškalová, Petra

    2007-01-01

    The aim of this work is confirming of incidence carpal tunnel syndrom in patients with spinal cord lesion. This ailment stem from repetitive loading of hands on propulsion of mechanical wheelchair. Work contains the causes of biginning, risk factors for patients, prevention, conservative and operation therapy. Thesis involves characteristic of patient after spinal cord injury, seat and wheelchair propulsion. The practice task contains case report of patient and suggestion of therapy for her. ...

  5. Analysis of the effect of attachment point bias during large space debris removal using a tethered space tug

    Science.gov (United States)

    Chu, Zhongyi; Di, Jingnan; Cui, Jing

    2017-10-01

    Space debris occupies a valuable orbital resource and is an inevitable and urgent problem, especially for large space debris because of its high risk and the possible crippling effects of a collision. Space debris has attracted much attention in recent years. A tethered system used in an active debris removal scenario is a promising method to de-orbit large debris in a safe manner. In a tethered system, the flexibility of the tether used in debris removal can possibly induce tangling, which is dangerous and should be avoided. In particular, attachment point bias due to capture error can significantly affect the motion of debris relative to the tether and increase the tangling risk. Hence, in this paper, the effect of attachment point bias on the tethered system is studied based on a dynamic model established based on a Newtonian approach. Next, a safety metric of avoiding a tangle when a tether is tensioned with attachment point bias is designed to analyse the tangling risk of the tethered system. Finally, several numerical cases are established and simulated to validate the effects of attachment point bias on a space tethered system.

  6. Spinal Cord Stimulation: An Alternative Concept of Rehabilitation?

    Science.gov (United States)

    Giugno, Antonella; Gulì, Carlo; Basile, Luigi; Graziano, Francesca; Maugeri, Rosario; Visocchi, Massimiliano; Iacopino, Domenico Gerardo

    2017-01-01

    Chronic low back and leg pain is a disabling condition, affecting, in most cases, older patients with congenital or acquired spinal stenosis or patients with failed back surgery syndrome. Spinal cord stimulation has been introduced as an effective therapeutic option for those patients who have previously been operated without significant clinical benefits, or for all those patients who are ineligible for traditional surgery. We report our experience with ten patients treated with spinal cord stimulation plus medication and physical therapy between November 2014 and September 2015. Inclusion criteria were: previous surgical treatments for lumbar stenosis and metameric instability and persistent or ingravescent disabling low back and leg pain, with a mean duration of symptoms of at least 18 months. A visual analog scale (VAS) was employed for back and leg pain, and the Oswestry Disability Index (ODI) score was determined, and findings were analyzed after 6 months. No intra- or postoperative complication was recorded. The mean VAS score for back pain decreased from 7.5 to 2.9, while leg VAS decreased from 8.2 to 3.0. Analysis of ODI values showed evident improvement in daily life activities, ranging from a median value of 75.7% to 32.7 % after the stimulation. Spinal cord stimulation has a recognized impact on the pain and on the quality of life of patients with failed back surgery syndrome.

  7. Wall effect on fluid–structure interactions of a tethered bluff body

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Sumant; Raghav, Vrishank, E-mail: vrishank@gatech.edu; Komerath, Narayanan, E-mail: komerath@gatech.edu; Smith, Marilyn

    2013-11-01

    Wind tunnel experiments have shown an unexplained amplification of the free motion of a tethered bluff body in a small wind tunnel relative to that in a large wind tunnel. The influence of wall proximity on fluid–structure interaction is explored using a compound pendulum motion in the plane orthogonal to a steady freestream with a doublet model for aerodynamic forces. Wall proximity amplifies a purely symmetric single degree of freedom oscillation with the addition of an out-of-phase force. The success of this simple level of simulation enables progress to develop metrics for unsteady wall interference in dynamic testing of tethered bluff bodies.

  8. Diamond surface functionalization with biomimicry - Amine surface tether and thiol moiety for electrochemical sensors

    Science.gov (United States)

    Sund, James B.; Causey, Corey P.; Wolter, Scott D.; Parker, Charles B.; Stoner, Brian R.; Toone, Eric J.; Glass, Jeffrey T.

    2014-05-01

    The surface of conducting diamond was functionalized with a terminal thiol group that is capable of binding and detecting nitrogen-oxygen species. The functionalization process employed multiple steps starting with doped diamond films grown by plasma enhanced chemical vapor deposition followed by hydrogen termination and photochemical attachment of a chemically protected amine alkene. The surface tether was deprotected to reveal the amine functionality, which enabled the tether to be extended with surface chemistry to add a terminal thiol moiety for electrochemical sensing applications. Each step of the process was validated using X-ray photoelectron spectroscopy analysis.

  9. Tethered satellite system dynamics and control review panel and related activities, phase 3

    Science.gov (United States)

    1991-01-01

    Two major tests of the Tethered Satellite System (TSS) engineering and flight units were conducted to demonstrate the functionality of the hardware and software. Deficiencies in the hardware/software integration tests (HSIT) led to a recommendation for more testing to be performed. Selected problem areas of tether dynamics were analyzed, including verification of the severity of skip rope oscillations, verification or comparison runs to explore dynamic phenomena observed in other simulations, and data generation runs to explore the performance of the time domain and frequency domain skip rope observers.

  10. Stabilization of periodic solutions in a tethered satellite system by damping injection

    DEFF Research Database (Denmark)

    Larsen, Martin Birkelund; Blanke, Mogens

    2009-01-01

    A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper...... to affect the orbit parameters. An approximation of the periodic solutions of the closed loop system is found as a series expansion in the parameter plane spanned by the controller gain and the bias term. The stability of the solutions is investigated using linear Floquet analysis of the variational...

  11. Electron Emitter for small-size Electrodynamic Space Tether using MEMS Technology

    DEFF Research Database (Denmark)

    Fleron, René A. W.; Blanke, Mogens

    2004-01-01

    Adjustment of the orbit of a spacecraft using the forces created by an electro-dynamic space-tether has been shown as a theoretic possibility in recent literature. Practical implementation is being pursued for larger scale missions where a hot filament device controls electron emission and the cu......Adjustment of the orbit of a spacecraft using the forces created by an electro-dynamic space-tether has been shown as a theoretic possibility in recent literature. Practical implementation is being pursued for larger scale missions where a hot filament device controls electron emission...... and other orbit parameters can be controlled for small sized missions, without on-board propulsion....

  12. Elasticity, adhesion and tether extrusion on breast cancer cells provide a signature of their invasive potential.

    Science.gov (United States)

    Smolyakov, Georges; Thiebot, Bénédicte; Campillo, Clément C; Labdi, Sid; Séverac, Childérick; Pelta, Juan; Dague, Etienne

    2016-10-05

    We use single cell force spectroscopy to compare elasticity, adhesion and tether extrusion on four breast cancer cell lines with an increasing invasive potential. We perform cell attachment/detachment experiments either on fibronectin or on another cell using an Atomic Force Microscope. Our study on the membrane tether formation from cancer cells show that they are easier to extrude from aggressive invasive cells. Measured elastic modulus values confirm that more invasive cells are softer. Moreover, the adhesion force increases with the invasive potential. Our results provide a mechanical signature of breast cancer cells that correlates with their invasivity.

  13. Exercise-Dependent Modulation of Neurourological Health Following Spinal Cord Injury

    Science.gov (United States)

    2014-11-01

    Dekaban, V. Omana, L. C. Weaver, CD11d integrin blockade reduces the systemic inflammatory response syndrome after spinal cord injury. Experimental...to weight support and control their trunk on their own. While studies aimed at limiting movements (hindlimb immobilization ) have a negative impact on... syndrome : thalamic hy- perexcitability after spinothalamic tract lesions. J. Neurosci. 28, 11959–11969. 92. Zhao, P., Waxman, S.G., and Hains, B.C. (2007

  14. Integrated test rig for tether hardware, real-time simulator and control algorithms: Robust momentum transfer validated

    Science.gov (United States)

    Kruijff, Michiel; van der Heide, Erik Jan

    2001-02-01

    In preparation of the ESA demonstration mission for a tethered sample return capability from ISS, a breadboard test has been performed to validate the robust StarTrack tether dynamics control algorithms in conjunction with the constructed hardware. The proposed mission will use hardware inherited from the YES mission (Kruijff, 1999). A tether spool is holding a 7 kg, 35 km Dyneema tether. A 45 kg re-entry capsule will be ejected by springs and then deployed by gravity gradient. The dynamics are solely controlled by a barberpole type friction brake, similar to the SEDS hardware. This hardware is integrated in a test rig, based on the TMM&M stand, that has been upgraded to accommodate both a Space Part (abruptly applied initial tether deployment speed, fine tensiometer, real-time space tether simulator using the tensiometer measurements as input, take-up roller deploying the tether at a simulator-controlled speed) and a Satellite Part (infra-red beams inside the tether canister, control computer estimating deployed length and required extra braking from the IRED interrupts, `barberpole' friction brake). So the set-up allows for a tether deployment with closed loop control, all governed by a real-time comprehensive tether dynamics simulation. The tether deployment is based on the two-stage StarTrack deployment. This scheme stabilizes the tether at an intermediate vertical stage (with 3 km deployed). When the orbit and landing site have synchronized, a high-speed deployment follows to a large angle. When the fully deployed 35-km tether swings to the vertical at approximately 40 m/s, it is cut at a prefixed time optimized for landing site accuracy. The paper discusses the tests performed to characterize the designed hardware, maturing of the developed algorithms with respect to the hardware noise levels and the difficulties and limitations of the test rig. It is found that the set-up can be applied to a variety of tether pre-mission tests. It is shown that the performed

  15. Restriction of the Patau syndrome to duplication of 13q22{yields}q.32 and possible role of interphase nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Helali, A.N.; Jafolla, A.K.; Oumsiych, M.B. [Duke Univ. Medical Center, Durham, NC (United States)

    1994-09-01

    A 10-year-old white male presented with mild microcephaly, slight growth and psychomotor retardation, soft fleshy ears, and normal facial features except for thin lips. No other significant anomalies were reported except for tethered cord discovered at age 8 years. The karyotype was found to be 46,XY,der(18)t(13;18)(q32;p11.32)pat. The mild phenotype appears to be primarily due to the duplication of 13q32{yields}qter. None of the cardinal features of trisomy 13 are found in cases of duplication of bands 13q22 to qter. This case shows that Patau syndrome phenotype does not originate by duplication of 13q32{yields}qter and may thus be restricted to 13q22 to 13q32. The variability in phenotypes points to an alternative explanation to the classical one of additive and interactive gene effects. This model involves effects of changes in chromosome position in the interphase nucleus on gene expression.

  16. What Is Spinal Cord Injury?

    Science.gov (United States)

    ... degrees of incomplete injury. 1 The closer the spinal injury is to the skull, the more extensive is ... 3 National Institute of Neurological Disorders and Stroke. Spinal cord injury: Hope through research. Retrieved June 19 , 2013 , from ...

  17. Intramedullary Cervical Spinal Cord Abscess.

    Science.gov (United States)

    Bakhsheshian, Joshua; Kim, Paul E; Attenello, Frank J

    2017-10-01

    Intramedullary spinal cord abscesses are rarely encountered in modern neurosurgical practice. Select patients are at high risk for developing an intramedullary spinal cord abscess, which can result in acute neurologic deficits. Patients with failed conservative management may benefit from early surgical intervention; however, the evidence is limited by level 3 studies. In this case presentation, the patient failed conservative management for a cervical intramedullary spinal cord abscess and developed acute neurologic deficits. The decision was made to perform an urgent cervical laminectomy and drainage to avoid any further decline that may have occurred with continued conservative management. Increased awareness of intramedullary spinal cord abscess is warranted for its clinical suspicion and emergent treatment in select circumstances. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Currarino syndrome: variability of imaging findings in 22 moleculargenetically identified (HLXB9 mutation) patients from five families; Currarino-Syndrom: Variabilitaet der bildgebenden Befunde bei 22 molekulargenetisch identifizierten (HLXB9-Mutation) Patienten aus fuenf Familien

    Energy Technology Data Exchange (ETDEWEB)

    Riebel, T.; Scheer, I. [Abt. Paediatrische Radiologie d. Klinik fuer Strahlenheilkunde, Charite - Universitaetsmedizin Berlin (Germany); Koechling, J. [Klinik fuer Paediatrie mit Schwerpunkt Onkologie u. Haematologie, Charite - Universitaetsmedizin Berlin (Germany); Oellinger, J. [Klinik fuer Strahlenheilkunde, Charite - Universitaetsmedizin Berlin (Germany); Reis, A. [Inst. fuer Humangenetik, Charite - Universitaetsmedizin Berlin u. Friedrich-Alexander-Univ., Erlangen-Nuernberg (Germany)

    2004-04-01

    Purpose: The imaging documents, obtained in connection with a primarily molecular genetic study on Currarino syndrome, should be evaluated with special respect to the constancy resp. the variability of findings in patients with proven HLBX9 mutations. Methods: In five female non-related index patients with clinicoradiologically diagnosed Currarino syndrome and further 53 members of their families, changes of the homeobox gene HLXB9 had been analysed. Variable mutations of this gene were found in a total of 23 individuals including the five index patients. In 22 of them the preexisting radiological documents could be collected as well as further imaging (plain sacrococcygeal radiography and/or lumbosacral MRI at least) initiated. This was followed by a detailed evaluation of pathological findings in the os sacrum/coccyx as well as in the presacral, the intraspinal, the anorectal, and the urogenital region, finally. Results: Imaging investigations revealed concomitant phenotypic abnormalities in all and even nine clinically asymptomatic individuals with proven HLXB9 mutations. A sacrococcygeal defect of varying intensity was depicted in every case. Complete Currarino triad (i.e. sacrococcygeal defect, presacral mass=anterior meningocele and/or tumor, anorectalmalformation) was only found in the five index patients and three further relatives. In all other cases, one or more of the following anomalies were detected with variable combination and with decreasing frequency: anterior meningocele (12) presacral tumor (11), tethered cord (10), intraspinal lipoma (8), anorectal stenosis/atresia (8), syringocele (5), rectal fistula (3), urogenital (2). (orig.) [German] Ziel: Die im Rahmen einer primaer molekulargenetischen Studie angefertigten ergaenzenden radiologischen Dokumente sollten im Hinblick auf die Konstanz bzw. Variabilitaet der bildgebenden Befunde bei gesichertem Currarino-Syndrom retrospektiv analysiert werden. Methode: Insgesamt 58 Mitglieder aus den Familien

  19. Complement activity in the cord blood of term neonates with the ...

    African Journals Online (AJOL)

    Cord blood samples from 11 term neonates whose placentas showed histological changes typical of the amniotic fluid infection syndrome were analysed in order to determine haemolytic activity of the classic and alternative complement pathways and serum levels of complement proteins and immunoglobulins. Although the ...

  20. Present and potential use of spinal cord stimulation to control chronic pain.

    Science.gov (United States)

    Song, Jason J; Popescu, Adrian; Bell, Russell L

    2014-01-01

    Spinal cord stimulation is an intervention that has become increasingly popular due to the growing body of literature showing its effectiveness in treating pain and the reversible nature of the treatment with implant removal. It is currently approved by the FDA for chronic pain of the trunk and limbs, intractable low back pain, leg pain, and pain from failed back surgery syndrome. In Europe, it has additional approval for refractory angina pectoris and peripheral limb ischemia. This narrative review presents the current evidence supporting the use of spinal cord stimulation for the approved indications and also discusses some emerging neuromodulation technologies that may potentially address pain conditions that traditional spinal cord stimulation has difficulty addressing. Narrative review. Spinal cord stimulation has been reported to be superior to conservative medical management and reoperation when dealing with pain from failed back surgery syndrome. It has also demonstrated clinical benefit in complex regional pain syndrome, critical limb ischemia, and refractory angina pectoris. Furthermore, several cost analysis studies have demonstrated that spinal cord stimulation is cost effective for these approved conditions. Despite the lack of a comprehensive mechanism, the technology and the complexity in which spinal cord stimulation is being utilized is growing. Newer devices are targeting axial low back pain and foot pain, areas that have been reported to be more difficult to treat with traditional spinal cord stimulation. Percutaneous hybrid paddle leads, peripheral nerve field stimulation, nerve root stimulation, dorsal root ganglion, and high frequency stimulation are actively being refined to address axial low back pain and foot pain. High frequency stimulation is unique in that it provides paresthesia free analgesia by stimulating beyond the physiologic frequency range. The preliminary results have been mixed and a large randomized control trial is underway

  1. Tethering a laminin peptide to a crosslinked collagen scaffold for biofunctionality.

    Science.gov (United States)

    Damodaran, Gopinath; Collighan, Russell; Griffin, Martin; Pandit, Abhay

    2009-06-15

    Cell adhesion peptide regulates various cellular functions like proliferation, attachment, and spreading. The cellular response to laminin peptide (PPFLMLLKGSTR), a motif of laminin-5 alpha3 chain, tethered to type I collagen, crosslinked using microbial transglutaminase (mTGase) was investigated. mTGase is an enzyme that initiates crosslinking by reacting with the glutamine and lysine residues on the collagen fibers stabilizing the molecular structure. In this study that tethering of the laminin peptide in a mTGase crosslinked collagen scaffold enhanced cell proliferation and attachment. Laminin peptide tethered crosslinked scaffold showed unaltered cell morphology of 3T3 fibroblasts when compared with collagen and crosslinked scaffold. The triple helical structure of collagen remained unaltered by the addition of laminin peptide. In addition a dose-dependent affinity of the laminin peptide towards collagen was seen. The degree of crosslinking was measured by amino acid analysis, differential scanning calorimeter and fourier transform infrared spectroscopy. Increased crosslinking was observed in mTGase crosslinked group. mTGase crosslinking showed higher shrinkage temperature. There was alteration in the fibrillar architecture due to the crosslinking activity of mTGase. Hence, the use of enzyme-mediated linking shows promise in tethering cell adhesive peptides through biodegradable scaffolds. Copyright 2008 Wiley Periodicals, Inc.

  2. Analysis and design of a friction brake for momentum exchange propulsion tethers

    Science.gov (United States)

    Lennert, Simone; Cartmell, Matthew P.

    2006-10-01

    The purpose of this paper is to present an engineering assessment of a proposal for a deployment brake for a momentum exchange tether. Tethers have attracted considerable interest amongst the propulsion community for many years for orbit raising, energy conversion, de-orbiting, and injection into interplanetary transfers, and the motivation for the work described in the paper is directly mission-oriented. The YES2 SpaceMail mission has been planned as a low-cost international effort to provide a facility for the return of small samples from the ISS back to Earth, based on an inflatable re-entry capsule and a mechanical tether system. The system will be lofted into orbit as part of a payload on a Foton/Bion rocket launcher. The brake design concept is based on the use of friction between the deploying tether and a short pole onto which several turns are wound, and the paper summarises the modelling work that has been done, and then discusses an experiment in which the premise was tested in the laboratory. The paper concludes with certain practical proposals for implementation.

  3. A kinetic Monte Carlo analysis for the production of singularly tethered carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Hilmer, Andrew J; Strano, Michael S [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Nair, Nitish, E-mail: strano@mit.edu [Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309 (United States)

    2010-12-10

    Nanoparticles that possess a single covalent tether to either another particle or a surface play an increasingly important role in nanotechnology, serving as a foundation for aggregation-based plasmonic sensors, chemically assembled framework structures, and scanning probe tips. Using a theoretical approach, we explore the reaction conditions necessary to maximize singular tethering for several cases of homogeneously dispersed nanoparticles, with a particular focus on single-walled carbon nanotubes. In the limit of particles of monodisperse size and equal site reactivity, the number of tethers versus the reaction conversion is statistically described by the well-known binomial distribution, with a variance that is minimal for the single tether case. However, solutions of nanoparticles often deviate from this ideal, and reaction events can introduce steric hindrance to neighboring sites or alter particle electronic properties, both of which can influence local reactivity. In order to study these cases we use the electron transfer reactions of single-walled carbon nanotubes. We find that the distribution in the number of monofunctional tubes, as a function of conversion, is largely dependent on the distribution of nanotube rate constants, and therefore tube chiralities, in the initial solution. As a contemporary example, we examine the implications of this result on the metallic-semiconductor separation of carbon nanotubes using electron transfer chemistry.

  4. APTEC: aptamer-tethered enzyme capture as a novel rapid diagnostic test for malaria.

    Science.gov (United States)

    Dirkzwager, Roderick M; Kinghorn, Andrew B; Richards, Jack S; Tanner, Julian A

    2015-03-18

    We report the rapid diagnosis of malaria by aptamer-tethered enzyme capture (APTEC) whereby an aptamer captures biomarker Plasmodium falciparum lactate dehydrogenase (PfLDH) then activity is measured colorimetrically. The robust test was sensitive (limit of detection = 4.9 ng mL(-1)) and could reliably diagnose malaria in clinical blood samples.

  5. Delivery of bFGF for Tissue Engineering by Tethering to the ECM

    Directory of Open Access Journals (Sweden)

    Chawapun Suttinont

    2015-01-01

    Full Text Available Delivery of growth factors to target cells is an important subject in tissue engineering. Towards that end, we have developed a growth factor-tethered extracellular matrix (ECM. Here, basic fibroblast growth factor (bFGF was tethered to extracellular matrix noncovalently. The designed ECM was comprised of 12 repeats of the APGVGV peptide motif derived from elastin as a stable structural unit and included the well-known cell adhesive RGD peptide as an active functional unit. To bind bFGF to the ECM, an acidic amino acid-rich sequence was introduced at the C-terminus of the ECM protein. It consisted of 5 repeats of 4 aspartic acids and a serine, DDDDS. bFGF has a highly basic amino acid domain. Therefore, bFGF was tethered to the ECM protein by electrostatic interaction. Cells cultured on bFGF-tethered ECM were well attached to the ECM and induced proliferation without addition of soluble bFGF.

  6. Optimal Cross-Wind Towing and Power Generation with Tethered Kites

    NARCIS (Netherlands)

    Williams, P.; Lansdorp, B.; Ockels, W.

    2007-01-01

    Non-powered flight vehicles such as kites can provide a means of transmitting wind energy from higher altitudes to the ground via tethers. Although there have been many proposals for systems to extract wind energy from higher altitudes, this paper focuses on the use of a light lifting body at the

  7. Titanium-tethered vancomycin prevents resistance to rifampicin in Staphylococcus aureus in vitro.

    Directory of Open Access Journals (Sweden)

    Martin Rottman

    Full Text Available Rifampicin is currently recognized as the most potent drug against Gram positive implant related infections. The use of rifampicin is limited by the emergence of bacterial resistance, which is often managed by coadministration of a second antibiotic. The purpose of this study was to determine the effectiveness of soluble rifampicin in combination with vancomycin tethered to titanium metal as a means to control bacterial growth and resistance in vitro. Bacterial growth was inhibited when the vancomycin-tethered titanium discs were treated with Staphylococcus aureus inocula of ≤2×10⁶ CFU, however inocula greater than 2×10⁶ CFU/disc adhered and survived. The combination of surface-tethered vancomycin with soluble rifampicin enhanced the inhibitory effect of rifampicin for an inoculum of 10⁶ CFU/cm² by one dilution (combination MIC of 0.008 mg/L versus 0.015 mg/L for rifampicin alone. Moreover, surface tethered vancomycin prevented the emergence of a rifampicin resistant population in an inoculum of 2×10⁸ CFU.

  8. Technical and economical assessment on tethered wind-energy systems (TWES)

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, O.; Maekawa, S.

    1982-06-01

    The objective of the work reported was to establish the potential of tethered wind energy systems for energy conversion in the upper atmosphere. Of the concepts investigated, the Vertical Takeoff and Landing (VTOL) lift generation concept had the highest potential as compared to balloon, wind and hybrid concepts.

  9. Folding of multidomain proteins: biophysical consequences of tethering even in apparently independent folding.

    Science.gov (United States)

    Arviv, Oshrit; Levy, Yaakov

    2012-12-01

    Most eukaryotic and a substantial fraction of prokaryotic proteins are composed of more than one domain. The tethering of these evolutionary, structural, and functional units raises, among others, questions regarding the folding process of conjugated domains. Studying the folding of multidomain proteins in silico enables one to identify and isolate the tethering-induced biophysical determinants that govern crosstalks generated between neighboring domains. For this purpose, we carried out coarse-grained and atomistic molecular dynamics simulations of two two-domain constructs from the immunoglobulin-like β-sandwich fold. Each of these was experimentally shown to behave as the "sum of its parts," that is, the thermodynamic and kinetic folding behavior of the constituent domains of these constructs seems to occur independently, with the folding of each domain uncoupled from the folding of its partner in the two-domain construct. We show that the properties of the individual domains can be significantly affected by conjugation to another domain. The tethering may be accompanied by stabilizing as well as destabilizing factors whose magnitude depends on the size of the interface, the length, and the flexibility of the linker, and the relative stability of the domains. Accordingly, the folding of a multidomain protein should not be viewed as the sum of the folding patterns of each of its parts, but rather, it involves abrogating several effects that lead to this outcome. An imbalance between these effects may result in either stabilization or destabilization owing to the tethering. Copyright © 2012 Wiley Periodicals, Inc.

  10. LBR and lamin A/C sequentially tether peripheral heterochromatin and inversely regulate differentiation.

    Science.gov (United States)

    Solovei, Irina; Wang, Audrey S; Thanisch, Katharina; Schmidt, Christine S; Krebs, Stefan; Zwerger, Monika; Cohen, Tatiana V; Devys, Didier; Foisner, Roland; Peichl, Leo; Herrmann, Harald; Blum, Helmut; Engelkamp, Dieter; Stewart, Colin L; Leonhardt, Heinrich; Joffe, Boris

    2013-01-31

    Eukaryotic cells have a layer of heterochromatin at the nuclear periphery. To investigate mechanisms regulating chromatin distribution, we analyzed heterochromatin organization in different tissues and species, including mice with mutations in the lamin B receptor (Lbr) and lamin A (Lmna) genes that encode nuclear envelope (NE) proteins. We identified LBR- and lamin-A/C-dependent mechanisms tethering heterochromatin to the NE. The two tethers are sequentially used during cellular differentiation and development: first the LBR- and then the lamin-A/C-dependent tether. The absence of both LBR and lamin A/C leads to loss of peripheral heterochromatin and an inverted architecture with heterochromatin localizing to the nuclear interior. Myoblast transcriptome analyses indicated that selective disruption of the LBR- or lamin-A-dependent heterochromatin tethers have opposite effects on muscle gene expression, either increasing or decreasing, respectively. These results show how changes in NE composition contribute to regulating heterochromatin positioning, gene expression, and cellular differentiation during development. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Titanium-tethered vancomycin prevents resistance to rifampicin in Staphylococcus aureus in vitro.

    Science.gov (United States)

    Rottman, Martin; Goldberg, Joel; Hacking, S Adam

    2012-01-01

    Rifampicin is currently recognized as the most potent drug against Gram positive implant related infections. The use of rifampicin is limited by the emergence of bacterial resistance, which is often managed by coadministration of a second antibiotic. The purpose of this study was to determine the effectiveness of soluble rifampicin in combination with vancomycin tethered to titanium metal as a means to control bacterial growth and resistance in vitro. Bacterial growth was inhibited when the vancomycin-tethered titanium discs were treated with Staphylococcus aureus inocula of ≤2×10⁶ CFU, however inocula greater than 2×10⁶ CFU/disc adhered and survived. The combination of surface-tethered vancomycin with soluble rifampicin enhanced the inhibitory effect of rifampicin for an inoculum of 10⁶ CFU/cm² by one dilution (combination MIC of 0.008 mg/L versus 0.015 mg/L for rifampicin alone). Moreover, surface tethered vancomycin prevented the emergence of a rifampicin resistant population in an inoculum of 2×10⁸ CFU.

  12. Defined subunit arrangement and rab interactions are required for functionality of the HOPS tethering complex.

    Science.gov (United States)

    Ostrowicz, Clemens W; Bröcker, Cornelia; Ahnert, Franziska; Nordmann, Mirjana; Lachmann, Jens; Peplowska, Karolina; Perz, Angela; Auffarth, Kathrin; Engelbrecht-Vandré, Siegfried; Ungermann, Christian

    2010-10-01

    Within the endomembrane system of eukaryotic cells, multisubunit tethering complexes together with their corresponding Rab-GTPases coordinate vesicle tethering and fusion. Here, we present evidence that two homologous hexameric tethering complexes, the endosomal CORVET (Class C core vacuole/endosome transport) and the vacuolar HOPS (homotypic vacuole fusion and protein sorting) complex, have similar subunit topologies. Both complexes contain two Rab-binding proteins at one end, and the Sec1/Munc18-like Vps33 at the opposite side, suggesting a model on membrane bridging via Rab-GTP and SNARE binding. In agreement, HOPS activity can be reconstituted using purified subcomplexes containing the Rab and Vps33 module, but requires all six subunits for activity. At the center of HOPS and CORVET, the class C proteins Vps11 and Vps18 connect the two parts, and Vps11 binds both HOPS Vps39 and CORVET Vps3 via the same binding site. As HOPS Vps39 is also found at endosomes, our data thus suggest that these tethering complexes follow defined but distinct assembly pathways, and may undergo transition by simple subunit interchange. © 2010 John Wiley & Sons A/S.

  13. Umbilical cord blood gas analysis.

    Science.gov (United States)

    Thorp, J A; Rushing, R S

    1999-12-01

    Umbilical cord blood gas and pH values should always be obtained in the high-risk delivery and whenever newborn depression occurs. This practice is important because umbilical cord blood gas analysis may assist with clinical management and excludes the diagnosis of birth asphyxia in approximately 80% of depressed newborns at term. The most useful umbilical cord blood parameter is arterial pH. Sampling umbilical venous blood alone is not recommended because arterial blood is more representative of the fetal metabolic condition and because arterial acidemia may occur with a normal venous pH. A complete blood gas analysis may provide important information regarding the type and cause of acidemia and sampling the artery and vein may provide a more clear assessment. The sampling technique is simple and easily mastered by any treatment person in the delivery room. Preheparinized syringes ensure a consistent dose and amount of heparin. Depending on how normality is defined and on the population studied, normal ranges for umbilical cord blood gas values vary (see Table 1). In general, the lower range for normal arterial pH extends to at least 7.10 and that for venous pH to at least 7.20. Many different factors during pregnancy, labor, and delivery can affect cord blood gases. Umbilical blood sampling for acid-base status at all deliveries cannot be universally recommended because many facilities do not have the capabilities to support such a practice and in doing so may impose an excessive financial burden. Considering the costs, the accumulated published data, and the nonspecificity of electronic fetal monitoring in the evaluation of fetal oxygenation, it may be more rational to implement universal cord blood gas analysis. Care providers and institutions with the logistical capabilities in place should consider the cost efficacy of routine cord blood gas analysis because it is the gold standard assessment of uteroplacental function and fetal oxygenation/acid-base status

  14. Nonfouling poly(ethylene oxide) layers end-tethered to polydopamine.

    Science.gov (United States)

    Pop-Georgievski, Ognen; Verreault, Dominique; Diesner, Mark-Oliver; Proks, Vladimír; Heissler, Stefan; Rypáček, František; Koelsch, Patrick

    2012-10-09

    Nonfouling surfaces capable of reducing protein adsorption are highly desirable in a wide range of applications. Coating of surfaces with poly(ethylene oxide) (PEO), a water-soluble, nontoxic, and nonimmunogenic polymer, is most frequently used to reduce nonspecific protein adsorption. Here we show how to prepare dense PEO brushes on virtually any substrate by tethering PEO to polydopamine (PDA)-modified surfaces. The chain lengths of hetero-bifunctional PEOs were varied in the range of 45-500 oxyethylene units (M(n) = 2000-20,000). End-tethering of PEO chains was performed through amine and thiol headgroups from reactive polymer melts to minimize excluded volume effects. Surface plasmon resonance (SPR) was applied to investigate the adsorption of model protein solutions and complex biologic medium (human blood plasma) to the densely packed PEO brushes. The level of protein adsorption of human serum albumin and fibrinogen solutions was below the detection limit of the SPR measurements for all PEO chains end-tethered to PDA, thus exceeding the protein resistance of PEO layers tethered directly on gold. It was found that the surface resistance to adsorption of lysozyme and human blood plasma increased with increasing length and brush character of the PEO chains end-tethered to PDA with a similar or better resistance in comparison to PEO layers on gold. Furthermore, the chain density, thickness, swelling, and conformation of PEO layers were determined using spectroscopic ellipsometry (SE), dynamic water contact angle (DCA) measurements, infrared reflection-absorption spectroscopy (IRRAS), and vibrational sum-frequency-generation (VSFG) spectroscopy, the latter in air and water.

  15. Methadone, Cocaine, Opiates and Metabolite Disposition in Umbilical Cord and Correlations to Maternal Methadone Dose and Neonatal Outcomes

    Science.gov (United States)

    de Castro, Ana; Jones, Hendreé E.; Johnson, Rolley E.; Gray, Teresa R; Shakleya, Diaa M; Huestis, Marilyn A

    2011-01-01

    Objectives To explore methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) umbilical cord disposition, correlate with maternal methadone dose and neonatal outcomes, and evaluate the window of drug detection in umbilical cord of in utero illicit drug exposure. Methods Subjects, 19 opioid-dependent pregnant women from two clinical studies, one comparing methadone and buprenorphine pharmacotherapy for opioid-dependence treatment, and the second examining monetary reinforcement schedules to maintain drug abstinence. Correlations were calculated for methadone and EDDP umbilical cord concentrations and maternal methadone dose, and neonatal outcomes. Cocaine- and opiate-positive umbilical cord concentrations were compared to those in placenta and meconium, and urine specimens collected throughout gestation. Results Significant positive correlations were found for umbilical cord methadone concentrations and methadone mean daily dose, mean dose during the 3rd trimester and methadone cumulative daily dose. Umbilical cord EDDP concentrations and EDDP/methadone concentration ratios were positively correlated to newborn length, peak neonatal abstinence syndrome (NAS) score and time-to-peak NAS score. Methadone concentrations and EDDP/methadone ratios in umbilical cord and placenta were positively correlated. Meconium identified many more cocaine and opiate positive specimens than umbilical cord. Conclusion Umbilical cord methadone concentrations were correlated to methadone doses. Also, our results indicate that methadone and EDDP concentrations might help to predict NAS severity. Meconium proved to be more suitable than umbilical cord to detect in utero exposure to cocaine and opiates; however, umbilical cord could be useful when meconium is unavailable due to in utero or delayed expulsion. PMID:21743375

  16. Bancos de cordón umbilical Umbilical cord banks

    OpenAIRE

    L. Madero

    2009-01-01

    La utilización de sangre de cordón como fuente de precursores hematológicos se remonta a 1983 cuando Boyse apuntó el potencial en progenitores existente en la sangre de cordón, realizándose un año más tarde las primeras experiencias sobre modelos murinos. Tuvieron que pasar más de cinco años para que Gluckman realizara la primera experiencia en humanos. Un niño afecto de anemia de Fanconi fue trasplantado con progenitores de sangre de cordón umbilical de su hermana HLA idéntica, realizándose ...

  17. Suicide in a spinal cord injured population

    DEFF Research Database (Denmark)

    Hartkopp, A; Brønnum-Hansen, Henrik; Seidenschnur, A M

    1998-01-01

    To determine the relation between functional status and risk of suicide among individuals with spinal cord injury (SCI).......To determine the relation between functional status and risk of suicide among individuals with spinal cord injury (SCI)....

  18. Disabled Vocal Cords: An Occupational Hazard.

    Science.gov (United States)

    Kahn, Norma B.

    1987-01-01

    A teacher points out the occupational hazard that can result from the misuse of the voice and ensuing vocal cord damage. Presents discussion of ways to avoid misusing the voice and prevent vocal cord damage. (MD)

  19. FAQs about Spinal Cord Injury (SCI)

    Science.gov (United States)

    ... What is paralysis? What is paraplegia? What is tetraplegia? What is a “complete” spinal cord injury? What ... What is paralysis? What is paraplegia? What is tetraplegia? What is a “complete” spinal cord injury? What ...

  20. Pericytes Make Spinal Cord Breathless after Injury.

    Science.gov (United States)

    Almeida, Viviani M; Paiva, Ana E; Sena, Isadora F G; Mintz, Akiva; Magno, Luiz Alexandre V; Birbrair, Alexander

    2017-09-01

    Traumatic spinal cord injury is a devastating condition that leads to significant neurological deficits and reduced quality of life. Therapeutic interventions after spinal cord lesions are designed to address multiple aspects of the secondary damage. However, the lack of detailed knowledge about the cellular and molecular changes that occur after spinal cord injury restricts the design of effective treatments. Li and colleagues using a rat model of spinal cord injury and in vivo microscopy reveal that pericytes play a key role in the regulation of capillary tone and blood flow in the spinal cord below the site of the lesion. Strikingly, inhibition of specific proteins expressed by pericytes after spinal cord injury diminished hypoxia and improved motor function and locomotion of the injured rats. This work highlights a novel central cellular population that might be pharmacologically targeted in patients with spinal cord trauma. The emerging knowledge from this research may provide new approaches for the treatment of spinal cord injury.