Bobble-head doll syndrome associated with Dandy-Walker syndrome. Case report.

PubMed

de Brito Henriques, José Gilberto; Henriques, Karina Santos Wandeck; Filho, Geraldo Pianetti; Fonseca, Luiz Fernando; Cardoso, Francisco; Da Silva, Márcia Cristina

2007-09-01

Bobble-head doll syndrome (BHDS) presents in childhood and is usually associated with lesions of the third ventricle. This disorder is characterized by stereotypical head movements of the type "yes-yes" (up and down) at a frequency of 2 to 3 Hz. Rarely, movements of the type "no-no" (side-to-side) are described. There are a few hypotheses to explain the mechanism responsible for BHDS, but its real pathophysiological characteristics are still unknown. The authors describe the case of a child born with hydrocephalus and Dandy-Walker syndrome. A ventriculoperitoneal shunt was implanted in the child because of progressive head enlargement. One year after shunt placement, she began making frequent horizontal head movements of the type "no-no". There were no other signs or symptoms. Imaging studies demonstrated small ventricles and a posterior fossa cyst with no signs of hypertension. The child's growth, development, and head circumference (within the 5th percentile) remained satisfactory. Three aspects of this case were of interest: the association of BHDS with Dandy-Walker syndrome, the rare occurrence of BHDS of the "no-no" type, and the absence of third ventricle dilation. The authors' findings support the hypothesis that cerebellar malformations themselves can

[Dandy-Walker variant: Case report].

PubMed

Cueva-Núñez, José E; Lozano-Bustillo, Alejandra; Irias-Álvarez, Merlyn S; Vásquez-Montes, Raúl F; Varela-González, Douglas M

Dandy Walker variant is defined by a variable hypoplasia of the cerebellar vermix with or without posterior fossa increase and without tentorium elevation. describe the case of a rare disease and emphasise the need to clarify the aetiology of prenatal malformations, as well as its multidisciplinary management. A male patient, 8 years of age, with a history of Infantile Cerebral Palsy and epilepsy, who was admitted with a history of tonic-clonic seizures. He was admitted due to psycho-motor developmental delay. During his hospitalisation, he had multiple seizure episodes, controlled with anticonvulsants. A computerized tomography was performed, in which communication was observed between the cisterna magna and fourth ventricle (the latter increased in size). In addition, the cerebellar vermix showed a partial hypoplasia. All these findings were compatible with a variant of the Dandy Walker syndrome. Dandy Walker variant may be asymptomatic and the images found may not indicate them as the cause of developmental disorders, due to its association with multiple syndromes and chromosomal abnormalities. Clinical presentation and prognosis depends on the related disorders, and a multidisciplinary approach is important, because the treatment depends on the symptoms presented. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Dandy-Walker variant associated with bipolar affective disorder

PubMed Central

Lingeswaran, Anand; Barathi, Deepak; Sharma, Gyaneswahr

2009-01-01

The Dandy-Walker malformation is a congenital brain malformation, typically involving the fourth ventricle and the cerebellum. To date, the Dandy-Walker syndrome has not been described in association with bipolar disorder type I mania, and therefore we briefly report the case of a Dandy-Walker variant associated with acute mania. A 10-year-old boy was brought by his mother to the outpatient clinic of the Department of Psychiatry of a tertiary care hospital, with symptoms of mania. The MRI brain of the patient showed a posterior fossa cystic lesion, a giant cisterna magna communicating with the fourth ventricle and mild hypoplasia of the cerebellar vermis, with the rest of the structures being normal and no signs of hydrocephalus. These findings showed that the patient had a Dandy-Walker variant. He responded partially to valproate and olanzepine, which controlled the acute manic symptoms in the ward. PMID:21887198

Dandy-Walker syndrome studied by computed tomography and pneumoencephalography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masdeu, J.C.; Dobben, G.D.; Azar-Kia, B.

1983-04-01

Based on air studies, some authors have disputed the ability of computed tomography (CT) to diagnose posterior fossa cysts. The authors correlated the pneumoencephalographic, CT, and pathological findings in 4 patients with classic Dandy-Walker syndrome. Three cases had been misdiagnosed as retrocerebellar arachnoid cysts because the fourth ventricle was incorrectly considered normal on brow-up or erect air studies, reflecting the inability of such studies to evaluate an agenetic vermis and deficient posterior medullary velum which are characteristic of Dandy-Walker malformation. Careful correlation with autopsy findings showed that even with complete agenesis of the inferior vermis, if the slit between themore » cerebellar hemispheres is narrow, the fourth ventricle could be misinterpreted as normal on pneumoencephalography and sagittal CT. Radionuclide studies, a small amount of air, or metrizamide may be needed to determine whether the cyst communicates with the subarachnoid space.« less

Dandy-Walker Variant with Schizophrenia: Comorbidity or Cerebellar Cognitive Affective Syndrome?

PubMed

Sinha, Pallavi; Tarwani, Jatin; Kumar, Pankaj; Garg, Amit

2017-01-01

Dandy-Walker complex (DWC) is a series of neurodevelopmental anomalies involving the posterior cranial fossa. The cerebellum has long been considered to be involved in motor coordination and balance. However, it has now been noted to play an important role in higher order cognitive, emotional, and behavioral functions. The concept of cerebellar cognitive affective syndrome, describing a coherent spectrum of cognitive and behavioral disturbances in adults following cerebellar damage has long been proposed. There have been reported cases of co-occurring psychiatric symptoms and DWC in literature, but the conclusive evidence for an association between the same remains lacking. Herein, we report a case of schizophrenia presenting along with Dandy-Walker Variant.

[Aicardi syndrome with Dandy-Walker type malformation].

PubMed

Laguado-Herrera, Yuly V; Manrique-Hernández, Edgar F; Peñaloza-Mantilla, Camilo A; Quintero-Gómez, David A; Contreras-García, Gustavo A; Sandoval-Martínez, Diana K

2015-07-16

Aicardi syndrome (OMIM 304050) was first described in 1965. Its classic triad consists of infantile spasms, partial or total agenesis of the corpus callosum and ocular disorders, such as chorioretinal lacunae. It has been posited that it is due to a mechanism involving X-linked dominant inheritance. We report the case of a full-term female, with no pathological familial history or parental consanguinity, with a prenatal diagnosis of Dandy-Walker type malformation, who presented convulsions, coloboma of the optic nerve, thoracic vertebral block with presence of scoliosis, transfontanellar ultrasound imaging showing agenesis of the corpus callosum and karyotype 46,XX. She was diagnosed with Aicardi syndrome and died at the age of one and a half months. The autopsy revealed supratentorial hydrocephalus with the presence of choroid plexus papilloma, a cyst in the posterior fossa (fourth ventricle), hypoplasia of the cerebellar vermis, agenesis of the left hemisphere of the corpus callosum and cerebellum, characteristic facial features of the syndrome, ogival palate, pectus excavatum, scoliosis, paraovarian cyst and hepatomegaly. Few cases of an association between the pathology and the presence of Dandy-Walker malformation have been described. We report a new case of the association, bearing in mind that the related disorders, mainly agenesis or hypoplasia of the corpus callosum, suggest the existence of an underlying genetic component. A study of the search for the aetiology must be focused on evaluating those genes that are related with neurodevelopment and its activation in the organogenesis stage. The definitive diagnosis establishes the prognosis, management and genetic counselling of the family.

Ocular findings in a case of trisomy 18 with variant of Dandy-Walker syndrome.

PubMed

Lim, Fong-Fong; Ng, Yan-Yan; Hu, Jui-Ming; Chen, Suh-Jen; Su, Pen-Hua; Chen, Jia-Yuh

2010-10-01

Trisomy 18 is the second most common chromosomal syndrome and has multiple dysmorphic features. However, ocular findings in trisomy 18 are rarely reported. Retinal folds are the most common ocular finding described to date, although retinal hypopigmentation, dysplasia, and areas of hemorrhage and gliosis are also found in trisomy 18. Dandy-Walker syndrome is a brain malformation that has been reported in association with numerous chromosomal abnormalities, although it has rarely been reported in association with trisomy 18. Here, we present a case of trisomy 18 with ocular pathology and variant of Dandy-Walker syndrome, a combination that has not previously been reported. Copyright © 2010 Taiwan Pediatric Association. Published by Elsevier B.V. All rights reserved.

Dandy-Walker syndrome: a review of fifteen cases evaluated by prenatal sonography.

PubMed

Russ, P D; Pretorius, D H; Johnson, M J

1989-08-01

Fifteen cases of the Dandy-Walker syndrome evaluated by prenatal sonography were reviewed retrospectively. A posterior fossa cyst communicating with the fourth ventricle was a feature in each case. Hydrocephalus was present in 53% of fetuses. Extracranial congenital malformations were documented in 60% of cases. Cardiac, genitourinary, gastrointestinal, and skeletal anomalies were noted. Of 12 available karyotypes, 4 (33%) were abnormal, including two cases of trisomy 18. Excluding terminated pregnancies, there was an overall mortality of 55%. Associated congenital defects contributed to 83% of the postnatal deaths. The Dandy-Walker syndrome can be accurately diagnosed in utero by sonographic demonstration of characteristic morphologic changes in the fetal posterior fossa. The prenatal examination should include an evaluation of associated supratentorial and extracranial defects. Coexisting structural and chromosomal anomalies occur frequently and adversely affect survival.

Moebius syndrome with Dandy-Walker variant and agenesis of corpus callosum.

PubMed

John, Jomol Sara; Vanitha, R

2013-09-01

Moebius syndrome is a rare congenital neurological disorder. The most frequent mode of presentation is facial diplegia with bilateral lateral rectus palsy, but there are variations. Here, we report a rare case of Moebius syndrome in a 15-month-old child with unilateral facial palsy, bilateral abducens nerve palsy with Dandy Walker variant, and complete agenesis of corpus callosum.

Dandy-Walker Malformation: is the 'tail sign' the key sign?

PubMed

Bernardo, Silvia; Vinci, Valeria; Saldari, Matteo; Servadei, Francesca; Silvestri, Evelina; Giancotti, Antonella; Aliberti, Camilla; Porpora, Maria Grazia; Triulzi, Fabio; Rizzo, Giuseppe; Catalano, Carlo; Manganaro, Lucia

2015-12-01

The study aims to demonstrate the value of the 'tail sign' in the assessment of Dandy-Walker malformation. A total of 31 fetal magnetic resonance imaging (MRI), performed before 24 weeks of gestation after second-line ultrasound examination between May 2013 and September 2014, were examined retrospectively. All MRI examinations were performed using a 1.5 Tesla magnet without maternal sedation. Magnetic resonance imaging diagnosed 15/31 cases of Dandy-Walker malformation, 6/31 of vermian partial caudal agenesis, 2/31 of vermian hypoplasia, 4/31 of vermian malrotation, 2/31 of Walker-Warburg syndrome, 1/31 of Blake pouch cyst and 1/31 of rhombencephalosynapsis. All data were compared with fetopsy results, fetal MRI after the 30th week or postnatal MRI; the follow-up depended on the maternal decision to terminate or continue pregnancy. In our review study, we found the presence of the 'tail sign'; this sign was visible only in Dandy-Walker malformation and Walker-Warburg syndrome. The 'tail sign' could be helpful in the difficult differential diagnosis between Dandy-Walker, vermian malrotation, vermian hypoplasia and vermian partial agenesis. © 2015 John Wiley & Sons, Ltd.

Moebius syndrome with Dandy-Walker variant and agenesis of corpus callosum

PubMed Central

John, Jomol Sara; Vanitha, R.

2013-01-01

Moebius syndrome is a rare congenital neurological disorder. The most frequent mode of presentation is facial diplegia with bilateral lateral rectus palsy, but there are variations. Here, we report a rare case of Moebius syndrome in a 15-month-old child with unilateral facial palsy, bilateral abducens nerve palsy with Dandy Walker variant, and complete agenesis of corpus callosum. PMID:24470815

Magnetic Resonance Imaging of An Adult with the Dandy-Walker Syndrome

PubMed Central

Stovall, Joyce M.; Venkatesh, Ramachandran

1988-01-01

A 30-year-old retired veteran was asymptomatic for two decades; he had carried out normal everyday living activities and was self-supporting. It was not until he was struck by an automobile, which resulted in head trauma, that the Dandy-Walker syndrome was incidentally discovered by computed tomography. Most patients with the Dandy-Walker syndrome or malformation are infants and seldom live into adulthood. Therefore, this patient is one of the very few patients with this malformation who remained in a state of cerebrospinal fluid compensation and lived to adulthood. The head trauma he received in the accident is believed to have activated neurological deficits, visual impairment, and diplopia. Although magnetic resonance imaging revealed severe hydrocephalus and lobar holoprosencephaly, the patient had no symptoms of increased intracranial pressure and no craniofacial deformities except for macrocephaly, and was capable of performing everyday living activities adequately. ImagesFigure 1Figure 2Figure 3 PMID:3249328

De Novo 3q22.3q24 Microdeletion in a Patient With Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome, Dandy-Walker Malformation, and Wisconsin Syndrome.

PubMed

Ramineni, Anand; Coman, David

2016-01-01

Interstitial deletions affecting the long arm of chromosome 3 have been associated with a broad phenotype. This has included the features of blepharophimosis-ptosis-epicanthus inversus syndrome, Dandy-Walker malformation, and the rare Wisconsin syndrome. The authors report a young female patient presenting with features consistent with all 3 of these syndromes. This has occurred in the context of a de novo 3q22.3q24 microdeletion including FOXL2 , ZIC1 , and ZIC4 . This patient provides further evidence for the role of ZIC1 and ZIC4 in Dandy-Walker malformation and is the third reported case of Dandy-Walker malformation to have associated corpus callosum thinning. This patient is also only the seventh to be reported with the rare Wisconsin syndrome phenotype.

Dandy-Walker malformation with postaxial polydactly: a new case of Pierquin syndrome.

PubMed

Passalacqua, Cristóbal A; Villegas, Victor P; Aracena, Mariana I; Mellado, Cecilia X

2013-04-01

The combination of Dandy-Walker malformation, other central nervous system anomalies, and postaxial polydactyly has been reported previously in two pairs of siblings. We propose the name 'Pierquin syndrome' for this combination and we report a new patient with this disorder.

[Prenatal diagnosis of the Dandy-Walker syndrome using sonography and computed tomography].

PubMed

Tölly, E; Ebner, F; Oberbauer, R W

1984-07-01

A case of Dandy-Walker-syndrome is presented, comparing the value of sonography and CT in intrauterine diagnosis. Together with a review of the literature of the subject, pathogenesis, morphology and prognosis in regard to the psychomotoric development are discussed.

Dandy-Walker malformation: analysis of 19 cases.

PubMed

Alexiou, George A; Sfakianos, George; Prodromou, Neofytos

2010-02-01

Dandy-Walker malformation is a congenital disorder that involves the cerebellum and fourth ventricle. Regarding treatment, there is still controversy over the optimum surgical management. In the current study, we present 19 consecutive cases of Dandy-Walker malformation diagnosed between January 1992 and January 2008 that were treated in our institute. All patients presented with hydrocephalus at the time of diagnosis and were treated surgically. Combined drainage of the ventricular system and posterior fossa cyst, using a 3-way connector was performed in 5 patients. Posterior fossa cyst drainage alone was performed in 10 patients and the remaining 4 patients were treated by ventricular drainage alone. All patients improved after treatment. Dandy-Walker malformation is a developmental abnormality of the central nervous system associated with various brain and extracranial abnormalities. Surgical treatment remains controversial, whereas prognosis varies greatly according to the severity of syndrome and associated comorbidities.

De Novo 3q22.3q24 Microdeletion in a Patient With Blepharophimosis–Ptosis–Epicanthus Inversus Syndrome, Dandy-Walker Malformation, and Wisconsin Syndrome

PubMed Central

Ramineni, Anand

2016-01-01

Interstitial deletions affecting the long arm of chromosome 3 have been associated with a broad phenotype. This has included the features of blepharophimosis–ptosis–epicanthus inversus syndrome, Dandy-Walker malformation, and the rare Wisconsin syndrome. The authors report a young female patient presenting with features consistent with all 3 of these syndromes. This has occurred in the context of a de novo 3q22.3q24 microdeletion including FOXL2, ZIC1, and ZIC4. This patient provides further evidence for the role of ZIC1 and ZIC4 in Dandy-Walker malformation and is the third reported case of Dandy-Walker malformation to have associated corpus callosum thinning. This patient is also only the seventh to be reported with the rare Wisconsin syndrome phenotype. PMID:28503614

Psychosis in a Case of Dandy-Walker Syndrome: A Case Report.

PubMed

Dawra, Ripu Daman; Karia, Sagar; Shah, Nilesh; Desousa, Avinash

2017-05-01

Dandy Walker Syndrome (DWS) is a congenital malformation with brain abnormalities, intellectual disabilities, epilepsy and visible structural changes in particular brain structures. We present here a case of psychosis in an 18-year-old male with DWS, epilepsy and intellectual disability. The purpose of this paper is to discuss the clinically relevant issues, psychopharmacological issues, neuropsychiatric manifestations and consultation liaison issues involved.

Dandy-Walker syndrome with severe velopharyngeal dysfunction: a contraindication for Le Fort I surgery?

PubMed

Nelke, Kamil H; Pawlak, Wojciech; Gerber, Hanna

2015-01-01

Dandy-Walker syndrome is a rare congenital brain deformation. Most symptoms are related with fourth ventricle and skull base malformations. Quite often, symptoms develop from infancy or progress rapidly. Cerebellar dysfunction, lack of muscle coordination, and skull deformities involving eye movement might be present. There are several Dandy-Walker syndrome complex types. We present a 23-year-old patient who had a severe dentofacial deformity with mandibular prognathism and extremely undeveloped maxillary bone resulting in palatopharyngeal and velopharyngeal dysfunction with complete lack of soft palate function resulting in increased speech tone and volume. Performing Le Fort I osteotomy in this case is greatly controversial and might result in even greater loss of function or even its total lack. Velopharyngeal complex is very important, and every surgeon should consider its value while planning Le Fort I osteotomies.

[The case of completed pregnancy of the patient with Dandy-Walker malformation].

PubMed

Beliaeva, E V; Lapshina, L V; Shaposhnikova, E V; Molgachev, A A

2018-01-01

Dandy-Walker malformation is a rare disease of the central nervous system pathology (congenital malformations of the fossa cranii posterior). The key features of this syndrome are an enlargement of the fourth ventricle; complete absence of the cerebellar vermis, the posterior midline area of cerebellar cortex responsible for coordination of the axial musculature; and cyst formation near the internal base of the skull. Pregnant patients with Dandy-Walker malformation are at high risk and are managed by multidisciplinary teams including neurologists and obstetricians. We present a case report of full-term pregnancy and uncomplicated delivery in a women with Dandy-Walker malformation.

Psychosis in a Case of Dandy-Walker Syndrome: A Case Report

PubMed Central

Dawra, Ripu Daman; Karia, Sagar; Shah, Nilesh

2017-01-01

Dandy Walker Syndrome (DWS) is a congenital malformation with brain abnormalities, intellectual disabilities, epilepsy and visible structural changes in particular brain structures. We present here a case of psychosis in an 18-year-old male with DWS, epilepsy and intellectual disability. The purpose of this paper is to discuss the clinically relevant issues, psychopharmacological issues, neuropsychiatric manifestations and consultation liaison issues involved. PMID:28658885

Scoliosis in Dandy-Walker syndrome: a case report and review of literature.

PubMed

Menon, Venugopal K; Sorur, Tamer M M; Al Ghafri, Khalifa A; Shahin, Marwan M H E

2017-12-01

This submission presents a case of scoliosis in a patient with established Dandy-Walker anomaly of the brain. A retrospective review of the patient's case notes was undertaken and the limited literature on this subject reviewed. The 13-year-old girl presented with a stiff right thoracic scoliosis typical of adolescent idiopathic scoliosis. The scoliotic segment also presented with significant lordosis. She had facial and truncal dysmorphism characteristic of Dandy-Walker complex and her brain images confirmed the diagnosis. She underwent scoliosis surgery by the posterior approach uneventfully. In conclusion scoliosis is hitherto unreported in the Dandy-Walker complex. The results of intervention appear satisfactory.

Scoliosis in Dandy-Walker syndrome: a case report and review of literature

PubMed Central

Sorur, Tamer M. M.; Al Ghafri, Khalifa A.; Shahin, Marwan M. H. E.

2017-01-01

This submission presents a case of scoliosis in a patient with established Dandy-Walker anomaly of the brain. A retrospective review of the patient’s case notes was undertaken and the limited literature on this subject reviewed. The 13-year-old girl presented with a stiff right thoracic scoliosis typical of adolescent idiopathic scoliosis. The scoliotic segment also presented with significant lordosis. She had facial and truncal dysmorphism characteristic of Dandy-Walker complex and her brain images confirmed the diagnosis. She underwent scoliosis surgery by the posterior approach uneventfully. In conclusion scoliosis is hitherto unreported in the Dandy-Walker complex. The results of intervention appear satisfactory. PMID:29354751

Familial renal-hepatic-pancreatic dysplasia and Dandy-Walker cyst: a distinct syndrome?

PubMed

Hunter, A G; Jimenez, C; Tawagi, F G

1991-11-01

Ivemark et al. first described sibs with renal-hepatic-pancreatic dysplasia (RHPD) (Ivemark BI, Oldfelt V, Zetterström R (1959): Acta Pediatr Scand 48: 1-11). Subsequent reports of affected individuals have described additional malformations and syndromes associated with RHPD. In this paper we describe 2 sibs with RHPD in association with Dandy-Walker cyst (DW). Through an examination of the pattern of associated malformations seen in RHPD we argue that RHPD-DW is a distinct monogenetic syndrome, and not an association.

PET/CT in a Patient Diagnosed With Dandy-Walker Syndrome.

PubMed

Infante, Jose R; Garcia, Lucia; Rayo, Juan I; Serrano, Justo; Dominguez, Maria L; Moreno, Manuel

2016-01-01

The Dandy-Walker syndrome (DWS) is a rare congenital posterior fossa malformation characterized by aplasia or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. We present a 52-year-old Caucasian man diagnosed with gastrointestinal stromal tumor and submitted to 18F-FDG PET/CT as a staging procedure. The patient was previously diagnosed with DWS in brain CT scan. PET/CT images revealed an ametabolic large cyst in the posterior fossa and hypoplasia of cerebellar vermis. The case is presented with the aim to show the appearance of this syndrome on PET/CT study.

The Most Common Comorbidities in Dandy-Walker Syndrome Patients: A Systematic Review of Case Reports.

PubMed

Stambolliu, Emelina; Ioakeim-Ioannidou, Myrsini; Kontokostas, Kimonas; Dakoutrou, Maria; Kousoulis, Antonis A

2017-09-01

Dandy-Walker syndrome (DWS) is a rare neurologic multi-entity malformation. This review aimed at reporting its main nonneurologic comorbidities. Following PRISMA guidelines, search in Medline was conducted (2000-2014, keyword: dandy-walker). Age, sex, country, DWS type, consanguinity or siblings with DWS, and recorded coexistent conditions (by ICD10 category) were extracted for 187 patients (46.5% male, 43% from Asia) from 168 case reports. Diagnosis was most often set in <1 year old (40.6%) or >12 years old (27.8%). One-third of cases had a chromosomal abnormality or syndrome (n = 8 PHACE), 27% had a cardiovascular condition (n = 7 Patent Ductus Arteriosus), 24% had a disease of eye and ear (n = 9 cataract); most common malignancy was nephroblastoma (n = 8, all Asian). Almost one-fifth had a mental illness diagnosis; only 6.4% had mild or severe intellectual disability. The spread of comorbidities calls for early diagnosis and multidisciplinary research and practice, especially as many cases remain clinically asymptomatic for years.

Chronic cerebral herniation in shunted Dandy-Walker malformation.

PubMed

Naidich, T P; Radkowski, M A; McLone, D G; Leestma, J

1986-02-01

A review of serial computed tomography (CT) scans of 25 patients with the Dandy-Walker malformation revealed six patients with chronic downward transincisural herniation of the cerebrum after shunt decompression of the posterior fossa cyst or malfunction of a lateral ventricular drainage catheter, or both. Chronic cerebral herniation was detected postmortem in a seventh patient with the Dandy-Walker malformation. The CT findings and autopsy appearance of this previously undescribed feature of shunted Dandy-Walker malformation are illustrated.

Dandy-Walker malformation: a rare association with hypoparathyroidism.

PubMed

Coban, Dilek; Akin, Mustafa Ali; Kurtoglu, Selim; Oktem, Suat; Yikilmaz, Ali

2010-12-01

Dandy-Walker malformation is characterized by cystic dilatation of the fourth ventricle and an enlarged posterior cranial fossa with upward displacement of the tentorium, lateral sinuses, and torcular, with agenesis or hypoplasia of the cerebellar vermis. Dandy-Walker malformation occurs in approximately the 4th week of gestation and is associated with various abnormalities involving the cardiac, skeletal, genitourinary, and gastrointestinal systems. The parathyroid gland also forms in the 3rd and 4th gestational weeks. Reported here is the case of a male infant with Dandy-Walker malformation with ventricular and atrial septal defect, unilateral renal agenesis, and hypoparathyroidism. To our knowledge, this rare association with neural crest events during the development of Dandy-Walker malformation has not been reported previously. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

[Fragile X syndrome with Dandy-Walker variant: a clinical study of oral and written communicative manifestations].

PubMed

Lamônica, Dionísia Aparecida Cusin; Ferraz, Plínio Marcos Duarte Pinto; Ferreira, Amanda Tragueta; Prado, Lívia Maria do; Abramides, Dagma Venturini Marquez; Gejão, Mariana Germano

2011-01-01

The Fragile X syndrome is the most frequent cause of inherited intellectual disability. The Dandy-Walker variant is a specific constellation of neuroradiological findings. The present study reports oral and written communication findings in a 15-year-old boy with clinical and molecular diagnosis of Fragile X syndrome and neuroimaging findings consistent with Dandy-Walker variant. The speech-language pathology and audiology evaluation was carried out using the Communicative Behavior Observation, the Phonology assessment of the ABFW - Child Language Test, the Phonological Abilities Profile, the Test of School Performance, and the Illinois Test of Psycholinguistic Abilities. Stomatognathic system and hearing assessments were also performed. It was observed: phonological, semantic, pragmatic and morphosyntactic deficits in oral language; deficits in psycholinguistic abilities (auditory reception, verbal expression, combination of sounds, auditory and visual sequential memory, auditory closure, auditory and visual association); and morphological and functional alterations in the stomatognathic system. Difficulties in decoding the graphical symbols were observed in reading. In writing, the subject presented omissions, agglutinations and multiple representations with the predominant use of vowels, besides difficulties in visuo-spatial organization. In mathematics, in spite of the numeric recognition, the participant didn't accomplish arithmetic operations. No alterations were observed in the peripheral hearing evaluation. The constellation of behavioral, cognitive, linguistic and perceptual symptoms described for Fragile X syndrome, in addition to the structural central nervous alterations observed in the Dandy-Walker variant, caused outstanding interferences in the development of communicative abilities, in reading and writing learning, and in the individual's social integration.

Dandy-Walker Malformation Presenting with Affective Symptoms.

PubMed

Batmaz, Mert; Balçik, Zeynep Ezgi; Özer, Ürün; Hamurişçi Yalçin, Burcu; Özen, Şakir

2017-09-01

Dandy-Walker malformation is defined by enlarged posterior fossa, cystic dilatation of the fourth ventricle, and cerebellar hypoplasia. Although developmental delay and mental retardation are common in Dandy-Walker malformation cases, other comorbid psychiatric conditions have been rarely reported. There are limited numbers of case reports about comorbidity of bipolar disorder with Dandy-Walker malformation in the literature. Herein, a Dandy-Walker malformation case presenting affective symptoms is reported, and psychiatric symptoms which might be seen in this rare malformation are discussed along with diagnosis, treatment, and follow-up processes. A 27-year-old male patient, hospitalized for compulsory treatment, had been diagnosed with Dandy-Walker malformation in childhood. First complaints were attention deficiency, behavioral problems, learning difficulties; and manic and depressive episodes have occurred during follow-ups. He recently complained of decreased need for sleep, irritability, and increased speed of thought, and psychiatric examination was consistent with manic episode. Cranial computed tomography (CT) revealed bilateral ventriculomegaly, enlarged third and fourth ventricles with posterior fossa cyst, and cerebellar hypoplasia. His treatment included 30 mg/day aripiprazole, 1000 mg/day valproic acid, 200 mg/day quetiapine, 4 mg/day biperiden, and 100 mg/month paliperidone palmitate. Beside its traditional role in the regulation of coordination and motor functions, cerebellum is increasingly emphasized for its involvement in the mood regulation. Thus, as seen in Dandy-Walker malformation, cerebellar anomalies are suggested to play a role in the pathophysiology of mood disorders. Further studies are needed to better understand the relationship between mood disorders and cerebellum. Moreover, treatment options should be considered carefully in terms of resistance to treatment and potential side effects, for psychiatric disorders occurring in these

Hydrocephalus in Dandy-Walker malformation.

PubMed

Spennato, Pietro; Mirone, Giuseppe; Nastro, Anna; Buonocore, Maria Consiglio; Ruggiero, Claudio; Trischitta, Vincenzo; Aliberti, Ferdinando; Cinalli, Giuseppe

2011-10-01

Even if the first description of Dandy-Walker dates back 1887, difficulty in the establishment of correct diagnosis, especially concerning differential diagnosis with other types of posterior fossa CSF collection, still persists. Further confusion is added by the inclusion, in some classification, of different malformations with different prognosis and therapeutic strategy under the same label of "Dandy-Walker". An extensive literature review concerning embryologic, etiologic, pathogenetic, clinical and neuroradiological aspects has been performed. Therapeutic options, prognosis and intellectual outcome are also reviewed. The correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a "real" Dandy-Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

[Genetic analysis of two cases with Dandy-Walker deformed fetus].

PubMed

Yao, Juan; Fang, Rong; Shen, Xueping; Shen, Guosong; Zhang, Su

2017-10-10

To explore the genetic etiology of two fetuses with Dandy-Walker malformation using single nucleotide polymorphism microarray (SNP-array). The fetuses and their parents were subjected to G banding karyotype analysis. The fetuses were also subjected to SNP-array analysis. The parents of both fetuses showed a normal karyotype. One fetus has a 46,X,?i(X)(q10), while for another conventional cell culture has failed. SNP-array showed that one fetus carried a 6p25.3p25.2 microdeletion, and another carried a Xp22.33p22.2 deletion and a Yq11.221q11 duplication. The abnormal fragments have involved FOXC1, SHOX and STS genes, which are associated with Dandy-Walker malformation. Alteration of 6p25.3p25.2, Xp22.33p22.2 copy numbers probably underlies the Dandy-Walker syndrome in the fetuses. The disorder may be attributed to abnormal expression of FOXC1, SHOX, and STS genes. SNP-array can provide an important supplement for prenatal diagnosis.

Dandy-Walker Malformation Presenting with Affective Symptoms

PubMed Central

BATMAZ, Mert; BALÇIK, Zeynep Ezgi; ÖZER, Ürün; HAMURİŞÇİ YALÇIN, Burcu; ÖZEN, Şakir

2017-01-01

Dandy-Walker malformation is defined by enlarged posterior fossa, cystic dilatation of the fourth ventricle, and cerebellar hypoplasia. Although developmental delay and mental retardation are common in Dandy-Walker malformation cases, other comorbid psychiatric conditions have been rarely reported. There are limited numbers of case reports about comorbidity of bipolar disorder with Dandy-Walker malformation in the literature. Herein, a Dandy-Walker malformation case presenting affective symptoms is reported, and psychiatric symptoms which might be seen in this rare malformation are discussed along with diagnosis, treatment, and follow-up processes. A 27-year-old male patient, hospitalized for compulsory treatment, had been diagnosed with Dandy-Walker malformation in childhood. First complaints were attention deficiency, behavioral problems, learning difficulties; and manic and depressive episodes have occurred during follow-ups. He recently complained of decreased need for sleep, irritability, and increased speed of thought, and psychiatric examination was consistent with manic episode. Cranial computed tomography (CT) revealed bilateral ventriculomegaly, enlarged third and fourth ventricles with posterior fossa cyst, and cerebellar hypoplasia. His treatment included 30 mg/day aripiprazole, 1000 mg/day valproic acid, 200 mg/day quetiapine, 4 mg/day biperiden, and 100 mg/month paliperidone palmitate. Beside its traditional role in the regulation of coordination and motor functions, cerebellum is increasingly emphasized for its involvement in the mood regulation. Thus, as seen in Dandy-Walker malformation, cerebellar anomalies are suggested to play a role in the pathophysiology of mood disorders. Further studies are needed to better understand the relationship between mood disorders and cerebellum. Moreover, treatment options should be considered carefully in terms of resistance to treatment and potential side effects, for psychiatric disorders occurring in these

Oral-facial-digital syndrome type 1 with hypothalamic hamartoma and Dandy-Walker malformation.

PubMed

Azukizawa, Takayuki; Yamamoto, Masahito; Narumiya, Seirou; Takano, Tomoyuki

2013-04-01

We report a 1-year-old girl with oral-facial-digital syndrome type 1 with multiple malformations of the oral cavity, face, digits, and central nervous system, including agenesis of the corpus callosum, the presence of intracerebral cysts, and agenesis of the cerebellar vermis, which is associated with the subarachnoid space separating the medial sides of the cerebellar hemispheres. This child also had a hypothalamic hamartoma and a Dandy-Walker malformation, which have not been reported previously. The clinical features, including cerebral malformations, in several types of oral-facial-digital syndrome, overlap with each other. Further accumulation of new case reports and identification of new genetic mutations in oral-facial-digital syndrome may provide novel and important insights into the genetic mechanisms of this syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

Nasopharyngeal teratoma, congenital diaphragmatic hernia and Dandy-Walker malformation - a yet uncharacterized syndrome.

PubMed

Gupta, N; Shastri, S; Singh, P K; Jana, M; Mridha, A; Verma, G; Kabra, M

2016-11-01

An association of congenital diaphragmatic hernia, dandy walker malformation and nasopharyngeal teratoma is very rare. Here, we report a fourth case with this association where chromosomal microarray and whole exome sequencing (WES) was performed to understand the underlying genetic basis. Findings of few variants especially a novel variation in HIRA provided some insights. An association of congenital diaphragmatic hernia, dandy walker malformation and nasopharyngeal teratoma is very rare. Here, we report a fourth case with this association where chromosomal microarray and whole exome sequencing (WES) was performed to understand the underlying genetic basis. Findings of few variants especially a novel variation in HIRA provided some insights. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dandy-Walker complex and syringomyelia in an adult: case report and discussion.

PubMed

Hammond, Christopher J; Chitnavis, Bhupal; Penny, Christopher C; Strong, Anthony J

2002-01-01

Syringomyelia in association with the Dandy-Walker complex is rare and only 17 cases have been reported, mostly as autopsy findings or incidental reports in series for other conditions. We present a further case report and discuss the possible pathogenetic mechanisms of syrinx formation in the presence of the Dandy-Walker complex. We emphasize the role of foramen magnum obstruction and alteration in cerebrospinal fluid flow dynamics in syrinx formation. The therapeutic importance of disimpaction of the foramen magnum is stressed. A 39-year-old man presented with headache. As a child, he had had cystoperitoneal and ventriculoperitoneal shunts inserted for hydrocephalus in association with the Dandy-Walker complex. On examination, the patient had limited upgaze but was otherwise normal. Magnetic resonance imaging revealed a large cervicothoracic syrinx and a Dandy-Walker cyst obstructing the foramen magnum. The cystoperitoneal shunt was revised. The patient's headaches resolved, and follow-up imaging demonstrated resolution of the syrinx and disimpaction of the foramen magnum. Disimpaction of the foramen magnum can resolve syringomyelia in patients with the Dandy-Walker complex. This can be achieved by a shunt procedure or by formal foramen magnum decompression. The rarity of the association between the Dandy-Walker complex and syringomyelia prevents firm conclusions from being made regarding the best management strategy for this condition.

Retinal vascular nonperfusion in siblings with Dandy-Walker variant.

PubMed

Rusu, Irene; Gupta, Mrinali Patel; Patel, Samir N; Oltra, Erica; Chan, R V Paul

2016-04-01

We report the case of a 2-month-old girl with Dandy-Walker variant who presented with strabismus, pathologic myopia measuring -16.00 D in each eye, diffuse chorioretinal atrophy and pigment mottling in the macula of both eyes, and areas of retinal capillary nonperfusion in both eyes. The patient's brother also has Dandy-Walker variant and was found to have bilateral severe myopia, myopic fundi, tilted optic disks with peripapillary atrophy, extensive areas of white without pressure, areas of lattice degeneration, and several chronic-appearing atrophic retinal holes surrounded by pigmentation. We hypothesize that children with Dandy-Walker variant may present with refractive errors such as pathologic myopia and with diverse retinal findings, including retinal ischemia. A lower threshold for ophthalmologic examination may be considered in this population. Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Dandy Walker Variant and Bipolar I Disorder with Graphomania

PubMed Central

Karakaş Uğurlu, Görkem; Çakmak, Selcen

2014-01-01

Cerebellum is known to play an important role in coordination and motor functions. In some resent studies it is also considered to be involved in modulation of mood, cognition and psychiatric disorders. Dandy Walker Malformation is a congenital malformation that is characterized by hypoplasia or aplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle and enlargement of the posterior fossa. When the volume of posterior fossa is normal, the malformation is called Dandy Walker Variant. Case is a 32 year old male with a 12 year history of Bipolar I Disorder presented with manic and depresive symptoms, including dysphoric and depressive affect, anhedonia, suicidal thoughts and behaviours, thoughts of fear about future, overtalkativeness and graphomania, increased energy, irregular sleep, loss of appetite, increased immersion in projects, irritability, agressive behavior, impulsivity. Cranial Magnetic Resonance Imaging was compatible to the morphological features of Dandy Walker Variant. PMID:25110509

Central diabetes insipidus, central hypothyroidism, renal tubular acidosis and dandy-walker syndrome: new associations.

PubMed

Alafif, M M; Aljaid, S S; Al-Agha, A E

2015-01-01

Dandy-Walker syndrome (DWS) is a rare brain malformation involving the cerebellum, and the fluid filled spaces around it, usually detected during the antenatal period or the early infancy. Clinically, it is characterized by mental retardation, developmental delay as well as cerebellar ataxia. It has been frequently associated with other conditions such as congenital heart diseases, primary hypothyroidism, and other disorders of the central nervous, gastrointestinal, genitourinary, and orthopedic systems. In this report, we describe a 3-month-old Saudi boy with the rare association of DWS with central diabetes insipidus, congenital central hypothyroidism, and type-2 renal tubular acidosis.

Central Diabetes Insipidus, Central Hypothyroidism, Renal Tubular Acidosis and Dandy-Walker Syndrome: New Associations

PubMed Central

Alafif, MM; Aljaid, SS; Al-Agha, AE

2015-01-01

Dandy-Walker syndrome (DWS) is a rare brain malformation involving the cerebellum, and the fluid filled spaces around it, usually detected during the antenatal period or the early infancy. Clinically, it is characterized by mental retardation, developmental delay as well as cerebellar ataxia. It has been frequently associated with other conditions such as congenital heart diseases, primary hypothyroidism, and other disorders of the central nervous, gastrointestinal, genitourinary, and orthopedic systems. In this report, we describe a 3-month-old Saudi boy with the rare association of DWS with central diabetes insipidus, congenital central hypothyroidism, and type-2 renal tubular acidosis. PMID:25861538

X-derived marker chromosome in patient with mosaic Turner syndrome and Dandy-Walker syndrome: a case report.

PubMed

Telepova, Alena S; Romanenko, Svetlana A; Lemskaya, Natalya A; Maksimova, Yulia V; Shorina, Asia R; Yudkin, Dmitry V

2017-01-01

Small supernumerary marker chromosomes can be derived from autosomes and sex chromosomes and can accompany chromosome pathologies, such as Turner syndrome. Here, we present a case report of a patient with mosaic Turner syndrome and Dandy-Walker syndrome carrying a marker chromosome. We showed the presence of the marker chromosome in 33.8% of blood cells. FISH of the probe derived from the marker chromosome by microdissection revealed that it originated from the centromeric region of chromosome X. Additionally, we showed no telomeric sequences and no XIST sequence in the marker chromosome. This is the first report of these two syndromes accompanied by the presence of a marker chromosome. Marker chromosome was X-derived and originated from centromeric region. Patient has mild symptoms but there is no XIST gene in marker chromosome. CPG137. Registered 03 March 2017.

[Congenital generalized lipodystrophy in a patient with Dandy Walker anomaly].

PubMed

Luna, Cecilia Inés; Fernández Cordero, Marisa; Escruela, Romina; Sierra, Valeria; Córdoba, Antonela; Goñi, Ignacio María; Berridi, Ricardo

2014-10-01

The objective of this study is to describe the unexpected association between the congenital generalized lipodystrophy (CGL) and Dandy Walker anomaly. We report the case of a 1-year-old infant who was hospitalized at her fourth month of life with Dandy Walker anomaly diagnosis and an increased social risk. During her hospitalization, she developed progressively: acromegaloid aspect, triangular fascia, hirsutism, lipoatrophy, muscle hypertrophy, clitoromegaly, abdominal distention, progressive hepatomegaly, and hypertriglyceridemia. This led to the clinical diagnosis of congenital generalized lipodystrophy. Importance should be given to the examination of clinical aspects as well as the interdisciplinary follow-up for proper detection of insulin resistance and diabetes, early puberty, cardiomyopathy, among others. In case of Dandy Walker anomaly, it should be checked the evolution to search intracranial hypertension signs. Due to its autosomal recessive nature, it is important to provide genetic counseling to the parents.

Endoscopic, single-catheter treatment of Dandy-Walker syndrome hydrocephalus: technical case report and review of treatment options.

PubMed

Sikorski, Christian W; Curry, Daniel J

2005-01-01

Optimal treatment for hydrocephalus related to Dandy-Walker syndrome (DWS) remains elusive. Patients with DWS-related hydrocephalus often require combinations of shunting systems to effectively drain both the supratentorial ventricles and posterior fossa cyst. We describe an endoscopic technique, whereby a frontally placed, single-catheter shunting system effectively drained the supratentorial and infratentorial compartments. This reduces the complexity and potential risk associated with the combined shunting systems required by so many with DWS-related hydrocephalus. Copyright 2005 S. Karger AG, Basel.

Dandy Walker Syndrome with Tessier 7 Cleft-a Rare Case Report and a Surgical Note on the Use of Vermilion Flap and Lazy W-Plasty.

PubMed

Dhupar, Vikas; Kumar, Praveen; Akkara, Francis; Kumar, Ananth

2012-09-01

The Dandy-Walker syndrome is a malformation of the brain that involves the mal-development of the cerebellum, associated with a cystic enlargement of this area, and frequently hydrocephalus. This malformation occurs in ~1 in 30,000 babies. It is seen mostly in females. Developmental anomalies like cleft lip, cleft palate, and cardiac malformation, orthopaedic and urinary structural abnormalities may also occur in 30% of the individuals. We report a case of Dandy Walker syndrome with Tessier 7 facial cleft with paramedian cleft palate in a 6 month old child. Surgical methods used to correct this anomaly include commissuroplasty, myoplasty of the orbicularis oris, and closure of the cleft cheek. Authors report a vermilion square flap technique that combines a lower lip mucocutaneous vermilion border flap with a lazy W-plasty to ensure a natural commissure and skin closure.

Neuroimaging of Dandy-Walker malformation: new concepts.

PubMed

Correa, Gustavo Gumz; Amaral, Lázaro Faria; Vedolin, Leonardo Modesti

2011-12-01

Dandy-Walker malformation (DWM) is the most common human cerebellar malformation, characterized by hypoplasia of the cerebellar vermis, cystic dilation of the fourth ventricle, and an enlarged posterior fossa with upward displacement of the lateral sinuses, tentorium, and torcular. Although its pathogenesis is not completely understood, there are several genetic loci related to DWM as well as syndromic malformations and congenital infections. Dandy-Walker malformation is associated with other central nervous system abnormalities, including dysgenesis of corpus callosum, ectopic brain tissue, holoprosencephaly, and neural tube defects. Hydrocephalus plays an important role in the development of symptoms and neurological outcome in patients with DWM, and the aim of surgical treatment is usually the control of hydrocephalus and the posterior fossa cyst. Imaging modalities, especially magnetic resonance imaging, are crucial for the diagnosis of DWM and distinguishing this disorder from other cystic posterior fossa lesions. Persistent Blake's cyst is seen as a retrocerebellar fluid collection with cerebrospinal fluid signal intensity and a median line communication with the fourth ventricle, commonly associated with hydrocephalus. Mega cisterna magna presents as an extraaxial fluid collection posteroinferior to an intact cerebellum. Retrocerebellar arachnoid cysts frequently compress the cerebellar hemispheres and the fourth ventricle. Patients with DWM show an enlarged posterior fossa filled with a cystic structure that communicates freely with the fourth ventricle and hypoplastic vermis. Comprehension of hindbrain embryology is of utmost importance for understanding the cerebellar malformations, including DWM, and other related entities.

Dandy-Walker malformation, genitourinary abnormalities, and intellectual disability in two families.

PubMed

Zaki, Maha S; Masri, Amira; Gregor, Anne; Gleeson, Joseph G; Rosti, Rasim Ozgur

2015-11-01

We report on two families, each with documented consanguinity and two affected with overlapping features of Dandy-Walker malformation, genitourinary abnormalities, intellectual disability, and hearing deficit. This phenotype shares similar findings with many well-known syndromes. However, the clinical findings of this syndrome categorize this as a new syndrome as compared with the phenotype of already established syndromes. Due to parental consanguinity, occurrence in siblings of both genders and the absence of manifestations in obligate carrier parents, an autosomal recessive pattern of inheritance is more likely. The authors believe that these families suggest a novel autosomal recessive cerebello-genital syndrome. Array CGH analyses of an affected did not show pathological deletions or duplications. © 2015 Wiley Periodicals, Inc.

Morphological manifestations of the Dandy-Walker syndrom in female members of a family.

PubMed

Titlić, Marina; Alfirević, Stanko; Kolić, Krešimir; Soldo, Anamarija; Tripalol, Ana Batoš

2015-03-01

The Dandy-Walker syndrome (DWS) is a hereditary disorder, appearing somewhat more frequently in women. The most important characteristics of the DWS are the lack of the cerebellar vermis, varying from a partial lack to a complete agenesis, and enlargement of the cerebrospinal spaces, especially in the fourth ventricle. The above mentioned morphological changes clinically manifest in ataxia, increased intracranial pressure and hydrocephalus. Here is presented a family with DWS, where the disease is contracted only by female members, in two generations, whereas no signs of DWS have been noticed in male family members. DWS is clinically manifested from early childhood to middle age, with the morphological changes varying from hypoplastic cerebellar vermis to widening of the brain ventricles and hydrocephalus and arachnoid cyst in the occipital part.

Psychiatric misdiagnoses in Dandy-Walker variant.

PubMed

Blaettner, C; Pfaffenberger, N M; Cartes-Zumelzu, F; Hofer, A

2015-01-01

Cases of intellectual impairment and aberrant behavior in patients with cerebellar diseases have been described since the early nineteenth century. Here, we report on a patient suffering from Dandy-Walker variant who presented with symptoms of obsessive compulsive disorder and delusional disorder. The current findings emphasize the potential relevance of focal cerebellar lesions as organic correlates of these disorders.

Extensive intracranial calcification of pseudo-TORCH syndrome with features of Dandy-Walker malformation.

PubMed

Patnaik, Ashis; Mishra, Sudhansu Sekhar; Das, Srikanta

2017-01-01

Pseudo-TORCH syndrome or congenital infection-like syndrome is a group of conditions which resemble congenital infections such as those caused by toxoplasmosis, rubella, cytomegalovirus (CMV), herpes (TORCH) group of organisms, clinico-radiologically, but serological tests are negative for the organisms. One of the variety shows features such as microcephaly, extensive intracranial calcification showing gross resemblance to congenital CMV infection, making its other name as microcephaly intracranial calcification syndrome (MICS). Dandy-Walker malformation (DWM), in addition to posterior fossa large cyst, cerebellar vermis hypoplasia, and hydrocephalus is often associated with agenesis of the corpus callosum and callosal lipomas, dysplasia of the brainstem, and cerebellar hypoplasia or dysgenesis. But radiological features of DWM with microcephaly and intracranial calcification are very unusual and have been rarely reported in the literature.[1] We report a case of infant showing clinical features suggestive of congenital CMV infection with negative serology and radiological imaging suggestive of DWM with extensive intracranial calcification. Pseudo-TORCH syndrome with radiological features of DWM is a congenital developmental abnormality. Inspite of hydrocephalus, it does not require cerebrospinal fluid (CSF) diversionary procedure due to lack of increased intracranial pressure. Conservative management for seizure disorder is the optimal therapy.

Coexistance of cerebral sinovenous thrombosis and Dandy Walker malformation in newborn.

PubMed

Gverić-Ahmetasević, Snjezana; Colić, Ana; Gverić, Tugomir; Gasparović, Vesna Elvedi; Pavlisa, Goran; Ozretić, David

2011-01-01

Cerebral sinovenous thrombosis in neonatal period may cause neurological impairment, epilepsy, and lead to stroke. It is caused primarily by coagulopathy of numerous reasons, occasionally perinatal asphyxia, traumatic delivery and hyperhomocysteinemia. Dandy-Walker malformation is characterized by agenesis or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. Dandy-Walker malformation, variant, and mega cisterna magna represent a spectrum of developmental anomalies. Insults to developing cerebellar hemispheres and the fourth ventricle are believed to be the cause of malformation. Our patient was born from noncomplicated pregnancy, noncomplicated nontraumatic vaginal delivery at term, excellent Apgar scores, without peculiarities in clinical status. She was brest-fed by the 42nd hour of life when she had rightsided seizures during sleep that repeated for five times in next 24 hours. Brain Ultrasound (US) revealed clot in left lateral ventricle, slight dilatation of left ventricle, both sided periventricular echodensity, ischemia, slight enlargement of forth ventricle and a bit smaller cerebellum. There was no visible flow through left transverse, superior sagittal and straight sinus. Magnetic Resonance (MRI) confirmed the finding and showed thrombosis of left and right transverse venous sinuses and confluence of sinuses. Electroencephalogram (EEG) showed leftsided focal changes. The newborn was treated with phenobarbiton for 8 days and had no convulsions during that period. All coagulation parameters, homocistein, lipoproteins (a) and D-dimers were normal. There were no mutations on FV R506Q, PT 20210A, MTHFR 677C/T. No antiphospholipides were found. Heart US showed no structural anomalies. No other patology or risk factors were present at the time. Before discharge, US showed hydrocephalus. Flow in affected sinuses was visible with color Doppler. MRI showed recanalization of affected sinuses, also

Oral-facial-digital syndrome type IX in a patient with Dandy-Walker malformation.

PubMed Central

Nagai, K; Nagao, M; Nagao, M; Yanai, S; Minagawa, K; Takahashi, Y; Takekoshi, Y; Ishizaka, A; Matsuzono, Y; Kobayashi, O; Itagaki, T

1998-01-01

We report a girl with oral, facial, and digital anomalies including multiple alveolar frenula, lobulated tongue with nodules, a posterior cleft palate, hypertelorism, a prominent forehead with a large anterior fontanelle, and postaxial polydactyly in both hands and the right foot, features compatible with the oral-facial-digital syndrome (OFDS). In addition, she had bilateral microphthalmia, optic disc coloboma, and retinal degeneration with partial detachment, thus establishing a diagnosis of OFDS type IX. Dandy-Walker malformation and retrobulbar cysts were observed on MRI. These additional malformations have not been reported in OFDS type IX. The frequent apnoeic spells which occurred immediately after birth were relieved after cystoperitoneal shunt implantation for hydrocephalus. Considering our case and previous reports of OFDS type IX, including two male sibs, a boy born to consanguineous parents, and three females, inheritance is probably autosomal recessive. Images PMID:9598735

A late presentation of Dandy-Walker malformation and aortic coarctation.

PubMed

Venturini, Elio; Magni, Lucia; Pucci, Giovanna; Mazzinghi, Fabio

2017-05-01

The Dandy-Walker malformation is a rare anomaly of the posterior cranial fossa. Concomitant brain or systemic malformations are frequent and can influence the outcome. Associated cardiac congenital defects usually induce a poor prognosis. We report a case of a 58-yearold man with hydrocephalus, in whom Dandy-Walker malformation was diagnosed, for the first time, after the demonstration of aortic coarctation. This association is very rare and only a few cases have been described; moreover, to our knowledge, this is the first description of this incidence in a middle-aged patient. The characteristic of diseases and physiopathologic features are discussed, focusing attention on the rare and late clinical manifestations.

Giant occipital meningocele in an 8-year-old child with Dandy-Walker malformation.

PubMed

Talamonti, Giuseppe; Picano, Marco; Debernardi, Alberto; Bolzon, Moreno; Teruzzi, Mario; D'Aliberti, Giuseppe

2011-01-01

The possibility of an association between Dandy-Walker malformation and occipital meningocele is well-known. However, just an overall number of about 40 cases have been previously reported. Giant occipital meningocele has been described only in three newborns. Incidence, pathology, clinical presentation, and proper management of this association are still poorly defined. An 8-year-old boy with Dandy-Walker malformation and giant (25 cm in diameter) occipital meningocele is presented. This boy was born without any apparent occipital mass and harbored no other significant malformations including hydrocephalus. On admission, he was neurologically intact and the giant occipital mass presented partially calcified cyst walls. Treatment consisted of the excision of the occipital malformation, cranioplasty, and cysto-peritoneal shunt. Outcome was excellent. To the best of our knowledge, among the few reported patients with Dandy-Walker malformation associated to occipital meningocele, this is the oldest one and the one with the largest occipital meningocele; he is unique with calcified walls of the occipital meningocele and the only one who survived the repair of the giant malformation. In Dandy-Walker malformation, occipital meningocele may develop and grow regardless of hydrocephalus. Giant size may be reached and the cyst may become calcified. Surgical repair may warrant favorable outcome.

New-onset psychosis associated with dandy-walker variant in an adolescent female patient.

PubMed

Ryan, Molly; Grenier, Ernesto; Castro, Anthony; Nemeroff, Charles B

2012-01-01

The relationship between psychotic disorders, in particular, schizophrenia, and neurodevelopmental abnormalities has been conceptualized in the latest literature. Dandy-Walker variant, defined by cystic dilatation of the fourth ventricle and hypoplasia of the inferior portion of the vermis without enlargement of the posterior fossa, is a distinctive entity believed to represent a mild subtype of Dandy-Walker complex. The authors hypothesize a correlation between new onset of psychosis and cerebellar abnormalities in an adolescent patient.

Schizophrenia-Like Psychosis and Dandy-Walker Variant Comorbidity: Case Report

PubMed Central

Kıvılcım, Yiğit; İzci, Filiz; Semiz, Umit Basar

2014-01-01

Dandy-Walker variant is a developmental malformation consisting of cerebellar hypoplasia and cystic dilatation of the fourth ventricle. Previous research has proposed a possible role for the cerebellum in cognition and in schizophrenia. In this paper we report a schizophrenia-like psychotic disorder in a 30 year-old woman with Dandy-Walker variant. The patient was treated with risperidone 6 mg/day, biperiden 4 mg/day and risperidone depot 50 mg injections fortnightly, and most of the symptoms were ameliorated within 2 months. The similar cognitive profile to populations with cerebellar pathology and rarity of the condition strongly suggests that there may be direct relationship between cerebellar pathology and appearence of psychotic symptoms. PMID:24605131

Neuropsychological and Behavioural Phenotype of Dandy-Walker Variant Presenting in Chromosome 22 Trisomy: A Case Study

ERIC Educational Resources Information Center

Searson, Ruth; Hare, Dougal Julian; Sridharan, Sridhar

2013-01-01

In this study, a case of Dandy-Walker variant syndrome associated with trisomy 22 in a 17-year-old man is described. This is the first account of this combination in a person surviving into adulthood, and the neuropsychological and behavioural presentation is described in detail and a clinical formulation is presented for the benefit of…

Neuropsychological and behavioural phenotype of Dandy-Walker variant presenting in chromosome 22 trisomy: a case study.

PubMed

Searson, Ruth; Hare, Dougal Julian; Sridharan, Sridhar

2013-06-01

In this study, a case of Dandy-Walker variant syndrome associated with trisomy 22 in a 17-year-old man is described. This is the first account of this combination in a person surviving into adulthood, and the neuropsychological and behavioural presentation is described in detail and a clinical formulation is presented for the benefit of researchers and clinicians.

Magnetic Resonance Imaging Diagnosis of Dandy-Walker-Like Syndrome in a Wire-Haired Miniature Dachshund

PubMed Central

KOBATAKE, Yui; MIYABAYASHI, Takayoshi; YADA, Naoko; KACHI, Shingo; OHTA, George; SAKAI, Hiroki; MAEDA, Sadatoshi; KAMISHINA, Hiroaki

2013-01-01

ABSTRACT A 12-week-old female Wire-haired miniature dachshund presented with non-progressive ataxia and hypermetria. Due to the animal’s clinical history and symptoms, cerebellar malformations were suspected. Computed tomography (CT) and magnetic resonance imaging (MRI) detected bilateral ventriculomegaly, dorsal displacement of the cerebellar tentorium, a defect in the cerebellar tentorium and a large fluid-filled cystic structure that occupied the regions where the cerebellar vermis and occipital lobes are normally located. The abovementioned cystic structure and the defect in the cerebellar tentorium were comparable to those seen in humans with Dandy-Walker syndrome. However, the presence of the cystic structure in the occipital lobe region was unique to the present case. During necropsy, the MRI findings were confirmed, but the etiology of the condition was not determined. PMID:23719692

Magnetic resonance imaging diagnosis of Dandy-Walker-like syndrome in a wire-haired miniature dachshund.

PubMed

Kobatake, Yui; Miyabayashi, Takayoshi; Yada, Naoko; Kachi, Shingo; Ohta, George; Sakai, Hiroki; Maeda, Sadatoshi; Kamishina, Hiroaki

2013-10-01

A 12-week-old female Wire-haired miniature dachshund presented with non-progressive ataxia and hypermetria. Due to the animal's clinical history and symptoms, cerebellar malformations were suspected. Computed tomography (CT) and magnetic resonance imaging (MRI) detected bilateral ventriculomegaly, dorsal displacement of the cerebellar tentorium, a defect in the cerebellar tentorium and a large fluid-filled cystic structure that occupied the regions where the cerebellar vermis and occipital lobes are normally located. The abovementioned cystic structure and the defect in the cerebellar tentorium were comparable to those seen in humans with Dandy-Walker syndrome. However, the presence of the cystic structure in the occipital lobe region was unique to the present case. During necropsy, the MRI findings were confirmed, but the etiology of the condition was not determined.

Dandy-Walker malformation: a review of 78 cases diagnosed by prenatal sonography.

PubMed

Has, Recep; Ermiş, Hayri; Yüksel, Atil; Ibrahimoğlu, Lem'i; Yildirim, Alkan; Sezer, Hande Delier; Başaran, Seher

2004-01-01

The purpose of this study was to determine the associated abnormalities and clinical outcomes of fetuses with Dandy-Walker malformations. Sonograms and medical reports of 78 cases were reviewed and information regarding each outcome was collected from autopsy records, hospital charts and specialists caring for the surviving infants. We identified 64 fetuses with classic Dandy-Walker malformation (DW) and 14 fetuses with Dandy-Walker variant (DWV). A high proportion (44.8%) of the parents were consanguineous. The spectrum and proportion of central nervous system (67.1 vs. 71.4%; p = 1.0) and other malformations (43.7 vs. 64.2%; p = 0.57) associated with DW and DWV were similar. Chromosome abnormalities were found in 9 of the 51 (17.6%) fetuses that underwent karyotype analysis. Only 4 of 64 (6.2%) DW and 3 of 14 (21.4%) DWV infants survived (p 0.14), and all surviving infants with DW or DWV had neurological disorders. DW and DWV cases show so many similarities that a clear-cut distinction is difficult. There was no significant difference in the spectrum of associated anomalies and postnatal prognosis between DW and DWV cases. Copyright 2004 S. Karger AG, Basel

Anomalous optic discs in a patient with a Dandy-Walker cyst.

PubMed

Orcutt, J C; Bunt, A H

1982-03-01

A 19-month-old female infant with a Dandy-Walker cyst had anomalous optic discs, each of which appeared to divide to form an accessory optic nerve. The discs probably lie within the spectrum of anomalous discs including optic nerve aplasia and hypoplasia, megallopapillae, morning glory disc, optic disc dysplasia, and optic nerve colobomas. The association of anomalous optic discs with a Dandy-Walker cyst has not been previously recognized. The ocular and brain malformations in this patient likely occurred during the fourth to eighth week of gestation, when the retinal ganglion cell axons were penetrating the optic nerve, and the rhombic lips were enlarging in early cerebellar development. The etiology of these anomalies is not known; however, teratogens, sporadic events, and genetic disorders should be considered.

Prenatal diagnosis and molecular characterization of a novel locus for Dandy-Walker malformation on chromosome 7p21.3.

PubMed

Liao, Can; Fu, Fang; Li, Ru; Yang, Xin; Xu, Qing; Li, Dong-Zhi

2012-01-01

We present three foetuses with Dandy-Walker malformation, intra-uterine growth restriction and multiple congenital abnormalities, who were studied by array-based comparative genomic hybridization and revealed a novel locus on chromosome 7p21.3. The association of pure chromosome 7p aberrations with Dandy-Walker malformation has rarely been reported. The present study suggests that the critical region associated with Dandy-Walker malformation is restricted to 7p21.3, including the cerebellar disease associated genes NDUFA4 and PHF14. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Dandy-Walker Malformation and Down Syndrome Association: Good Developmental Outcome and Successful Endoscopic Treatment of Hydrocephalus

PubMed Central

Nigri, Flavio; Cabral, Isaias Fiuza; da Silva, Raquel Tavares Boy; Pereira, Heloisa Viscaíno; Ribeiro, Carlos Roberto Telles

2014-01-01

The association of Down syndrome (DS) with Dandy Walker malformation (DWM) is extremely rare, with only 3 cases reported to date. All cases reported have shown a bad life expectancy and a bad developmental outcome. The present case reveals the possibility of a good prognosis. A 19-month-old male patient had successful endoscopic hydrocephalus treatment and a good developmental outcome. He probably had a better outcome because of good DS and DWM prognostic parameters. Our patient suffered from a DWM with vermis identification of 2 fissures and 3 lobes and a DS with a well-preserved tonus, which was not associated with other congenital systemic defects. We may conclude that the prognosis of DS-DWM association may separately depend on the degree of clinical and neurological involvement of each malformation. PMID:24932176

Dandy-walker malformation and down syndrome association: good developmental outcome and successful endoscopic treatment of hydrocephalus.

PubMed

Nigri, Flavio; Cabral, Isaias Fiuza; da Silva, Raquel Tavares Boy; Pereira, Heloisa Viscaíno; Ribeiro, Carlos Roberto Telles

2014-05-01

The association of Down syndrome (DS) with Dandy Walker malformation (DWM) is extremely rare, with only 3 cases reported to date. All cases reported have shown a bad life expectancy and a bad developmental outcome. The present case reveals the possibility of a good prognosis. A 19-month-old male patient had successful endoscopic hydrocephalus treatment and a good developmental outcome. He probably had a better outcome because of good DS and DWM prognostic parameters. Our patient suffered from a DWM with vermis identification of 2 fissures and 3 lobes and a DS with a well-preserved tonus, which was not associated with other congenital systemic defects. We may conclude that the prognosis of DS-DWM association may separately depend on the degree of clinical and neurological involvement of each malformation.

Prenatal diagnosis of herniated Dandy-Walker cysts.

PubMed

Lee, Wesley; Vettraino, Ivana M; Comstock, Christine H; Lal, Nirish; Kazmierczak, Chris; Shetty, Anil; Raff, Gil; Zakalik, Karol; Romero, Roberto

2005-06-01

The purpose of this series is to describe the prenatal diagnosis and pregnancy outcome of fetuses affected with Dandy-Walker malformation in which a posterior cyst herniated through a bony defect of the occipital skull, foramen magnum, or both. Two- and 3-dimensional sonography were used to examine 2 fetuses with poorly delineated cerebellar structures and a large posterior cystic neck mass. Fetal magnetic resonance imaging (MRI) was added to this evaluation as a complementary diagnostic modality. Three-dimensional sonography helped characterize the precise site of cyst herniation through the occipital skull or foramen magnum. Fetal MRI confirmed the sonographic findings. Neonatal MRI studies identified heterotopic gray matter as evidence of a neuronal migration disorder in both fetuses. The second fetus also had agenesis of the corpus callosum. Retrospective review of the fetal MRI (25.9 weeks' menstrual age) and 3-dimensional sonographic (18.7 weeks' menstrual age) studies confirmed ventricular wall nodularity involving the occipital horns of the second fetus. The antenatal detection of a large posterior cystic neck mass and a poorly defined or nonvisualized cerebellar vermis suggest Dandy-Walker malformation with a herniated cyst. Three-dimensional sonography and fetal MRI are important adjunctive methods that can be used to evaluate the herniation site and a possible neuronal migrational disorder.

The dysraphic state of the posterior fossa. Clinical review of the Dandy-Walker syndrome and the so-called arachnoid cysts.

PubMed

Carteri, A; Gerosa, M; Gaini, S M; Villani, R

1979-01-01

The Authors report their case material concerning some basic items of the dysraphic pathology of the Posterior Fossa: 22 cases of Dandy Walker syndromes (DWS) and "Arachnoid Cysts" (PFC). The mean clinical findings (predominant involvement of the vestibular structures of the brain stem in the DWS, frequent epileptic seizures and some cases of hypothalamic disturbances in the PFC) are discussed in the light of current embryological theories on Weed's "area membranacea". Finally the results of differential surgical treatments are examined: good or satisfactory results were obtained with shunts, while still debatable seems to be the direct surgical approach.

Long-term follow-up of successful treatment for dandy-walker syndrome (DWS).

PubMed

Lin, Jun; Liang, Guobiao; Liang, Yong; Kou, Yun

2015-01-01

Various managements of Dandy-Walker syndrome (DWS) from open excision of the cysts to CSF diversion have been reported. However, optimal treatment for DWS remains elusive. Cyst fenestration was employed firstly, but failed 15 days after the surgery. Then a ventriculoperitoneal (VP) shunt was inserted and the patient discharged from hospital 13 days after the second surgery. During the 12-year follow-up, CT scanning, MRI, and X-radiation were performed. CT scanning showed that the size of ventricular system gradually returned to normal. MRI revealed similar changes of the ventricular system, and further revealed the development of supratentorial brain. The results of X-radiation during the follow-up years showed that the peritoneal end of the shunt might be already out of the abdominal cavity. Slow refilling of the shunt valve may suggest that the shunt could be probably not functional. The treatment of the patient was successfully, and the abnormal cerebral ventricle system gradually recovered during the 12-year follow-up. Because the patient might be probably independent on the shunt, further choice of the shunt removal should be thinking thoroughly, considering both safety and quality of life for the patient.

Long-term follow-up of successful treatment for dandy-walker syndrome (DWS)

PubMed Central

Lin, Jun; Liang, Guobiao; Liang, Yong; Kou, Yun

2015-01-01

Background: Various managements of Dandy-Walker syndrome (DWS) from open excision of the cysts to CSF diversion have been reported. However, optimal treatment for DWS remains elusive. Methods: Cyst fenestration was employed firstly, but failed 15 days after the surgery. Then a ventriculoperitoneal (VP) shunt was inserted and the patient discharged from hospital 13 days after the second surgery. During the 12-year follow-up, CT scanning, MRI, and X-radiation were performed. Results: CT scanning showed that the size of ventricular system gradually returned to normal. MRI revealed similar changes of the ventricular system, and further revealed the development of supratentorial brain. The results of X-radiation during the follow-up years showed that the peritoneal end of the shunt might be already out of the abdominal cavity. Slow refilling of the shunt valve may suggest that the shunt could be probably not functional. Conclusion: The treatment of the patient was successfully, and the abnormal cerebral ventricle system gradually recovered during the 12-year follow-up. Because the patient might be probably independent on the shunt, further choice of the shunt removal should be thinking thoroughly, considering both safety and quality of life for the patient. PMID:26770421

Neurocutaneous melanosis associated with Dandy-Walker malformation. case report and review of the literature.

PubMed

Berker, M; Oruckaptan, H H; Oge, H K; Benli, K

2000-11-01

Neurocutaneous melanosis is a rare dysmorphogenesis associated with single or multiple giant pigmented cutaneous nevi and diffuse involvement of the leptomeninges anywhere in the central nervous system (CNS). It is interesting that almost 8-10% of patients had associated Dandy-Walker malformation in the literature, suggesting a common origin of the developmental abnormalities. In this article, we present a 2-year-old patient with neurocutaneous melanosis associated with Dandy-Walker malformation. We reviewed the literature and discuss the pathogenesis based on the preferred hypotheses so far. Copyright 2001 S. Karger AG, Basel.

Oral findings and dental treatment in a patient with Dandy-Walker syndrome: a case report.

PubMed

Kusumoto, Yasuka; Shinozuka, Osamu

2014-01-01

Dandy-Walker syndrome (DWS) is congenital disease characterized by hypoplasia of the cerebellum, the formation of cysts that communicate with the fourth ventricle of the posterior cranial fossa, and hydrocephalus. In addition to various other complications, cleft lip/palate, facial retrognathia, a high-arched palate, and maldentition occur at an increased frequency in patients with DWS. However, few studies have reported the dental manifestations of DWS. Herein, we report the clinical manifestations, oral findings, and dental management of a DWS patient who was treated under general anesthesia. Poor oral hygiene, gingivitis, and several congenital dental abnormalities (e.g., generalized microdontia, conical tooth, transposition, and congenitally missing teeth) were observed. This report is the first to describe the oral findings and dental treatment of DWS. Our findings emphasize the importance of a multidisciplinary approach in the diagnosis and treatment of DWS. © 2013 Special Care Dentistry Association and Wiley Periodicals, Inc.

Severe myopia with unusual retinal anomalies and Dandy-Walker sequence in two sibs. A distinct new neuro-ocular disorder.

PubMed

de Crecchio, Giuseppe; Cennamo, Gilda; de Leeuw, Nicole; Ventruto, Maria Luisa; Lonardo, Maria Concetta; Friso, Patrizia; Ventruto, Valerio

2013-12-01

We have observed a male and a female, sibs of non-consanguineous parents, affected by severe myopia with characteristic retinal defects and Dandy-Walker variant. The peculiarity of the retinopathy consists of pathological myopia with anomalous vitreal fenestrated membranes in the retinal periphery. We suppose that these associations may configure a new genetic syndrome.

[Asphyxiating thoracic dysplasia associated with hepatic ductal hypoplasia, agenesis of the corpus callosum and Dandy-Walker syndrome].

PubMed

Trabelsi, M; Hammou-Jeddi, A; Kammoun, A; Bennaceur, B; Gharbi, H A

1990-01-01

The authors report on a case of a newborn with asphyxiating thoracic dysplasia who died 36 h after birth. This chondrodysplasia was associated with hepatic ductular hypoplasia, agenesis of the corpus callosum and Dandy-Walker malformation. To our knowledge, such an association has not previously been reported in the literature.

Dandy-Walker syndrome with duplex kidney abnormalities in trisomy 18 - A rare case report.

PubMed

Wang, Tun-Jun; Li, Yi-Ying; Wu, Wan-Ju; Lin, Chi-Kang; Wang, Chun-Kai; Wang, Chen-Yu; Hwang, Kwei-Shuai; Su, Her-Young

2017-10-01

Trisomy 18 is one of the major numerical chromosomal disorders. The incidence of trisomy 18 is approximately one in 6000 live births. Dandy-Walker malformation (DWM) is the most common congenital malformation of the cerebellum, with an incidence of about one in 5000 live births. The incidence of trisomy 18 associated with DWM is rare and long-term survival rate is very low. A case involving a 39-year-old pregnant female with a case of trisomy 18 associated with DWM. The incidence of trisomy 18 associated with DWM is rare, and our report presents an unusual case that supplements our knowledge of this condition. We report a case involving a 39-year-old pregnant female with a case of trisomy 18 associated with Dandy-Walker malformation (DWM). Fetal ultrasonography showed hypoplasia of the cerebellar vermis and dilatation of the fourth ventricle and was characterized by an enlarged posterior fossa. Fetal magnetic resonance imaging showed inferior vermian hypoplasia and a large posterior fossa cyst communicating with the fourth ventricle causing high insertion of the torcular herophili, which was compatible with DWM. Furthermore, the karyotyping report revealed trisomy 18. The incidence of trisomy 18 associated with DWM is rare, and our report presents an unusual case that supplements our knowledge of this condition. Copyright © 2017. Published by Elsevier B.V.

A rare case of giant occipital meningocele with Dandy Walker Syndrome: Can it grow bigger than this?

PubMed

Mankotia, Dipanker Singh; Satyarthee, Guru Dutta; Singh, Bhoopendra; Sharma, Bhawani Shankar

2016-01-01

Association of Dandy-Walker syndrome with occipital meningocele (OMC) is extremely rare and about thirty cases are reported till date in the Western literature. However, OMC is classified by Talamonti et al . into small, large, and giant categories with respective diameters were upto 5 cm in small, large with 5-9 cm, and giant with >9 cm. Usually the size of OMC progressively increases as raised intracranial pressure leads to compensatory cerebrospinal fluid escape into sac with the growth of children. Authors report an interesting case of an 18-month-old female child with extra-gigantic OMC, whose size was almost same since birth, representing the first case of its kind, who underwent successful surgical repair. Clinical presentation, radiological features, and surgical management options in literature are reviewed briefly for this rare disease association.

Impulsive behavior and recurrent major depression associated with dandy-walker variant.

PubMed

Kim, Ji Hyun; Kim, Tae Ho; Choi, Young Chil; Chung, Soon-Cheol; Moon, Seok Woo

2013-09-01

Reported herein is a case of recurrent major depression with impulse control difficulty in a 33-year-old man with Dandy-Walker variant. He was diagnosed as having major depressive disorder a year before he presented himself to the authors' hospital, and had a history of three-time admission to a psychiatric unit in the previous 12 months. He was readmitted and treated with sodium valporate 1,500 mg/day, mirtazapine 45 mg/day, and quetiapine 800 mg/day during the three months that he was confined in the authors' hospital, and the symptoms were reduced within three months but remained thereafter. This is the only case so far reporting recurrent depression with impulse control difficulty associated with Dandy-Walker variant. This case implies that any cerebellar lesion may cause the appearance of recurrent depression with impulse control difficulty in major depressive disorder.

Diagnosis of a case of Dandy-Walker malformation aided by measurement of the brainstem-vermis angle at 14 weeks gestation.

PubMed

Ichizuka, Kiyotake; Mishina, Miyuki; Hasegawa, Junichi; Matsuoka, Ryu; Sekizawa, Akihiko; Pooh, Ritsuko K

2015-05-01

Reported is a fetal Dandy-Walker malformation that was strongly suspected in the first trimester through measurement of the brainstem-vermis (B-V) angle, which was found to be 119° on transvaginal ultrasound examination at 14 weeks and 2 days gestation. Definitive diagnosis of the Dandy-Walker malformation was made by magnetic resonance imaging following stillbirth. Ultrasound measurement of the B-V angle may be a useful index for prenatal diagnosis of Dandy-Walker anomalies during early pregnancy. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

The Dandy-Walker malformation. A review of 40 cases.

PubMed

Hirsch, J F; Pierre-Kahn, A; Renier, D; Sainte-Rose, C; Hoppe-Hirsch, E

1984-09-01

Forty cases of Dandy-Walker malformation referred to the Hôpital Necker Enfants-Malades between 1969 and 1982 have been reviewed. The incidence of the malformation in hydrocephalus was 2.4%. There was a slight, statistically insignificant, female prevalence. Hydrocephalus should not be included in the definition of the syndrome. In 80% of the cases, it was actually a post-natal complication of the malformation and most often developed within 3 months after birth. In 80% of the cases, a communication, although insufficient, was found between the dilated 4th ventricle and the subarachnoid space. Since this communication is probably established through the foramina of Luschka, the definition of the Dandy-Walker malformation should only include atresia of the foramen of Magendie. Associated brain and systemic malformations were numerous. Among facial anomalies, facial angiomas were found in 10% of our cases. The association of facial and cardiovascular anomalies favors the hypothesis that the onset of the malformation occurs between the formation and the migration of the cells of the neural crest (that is, between the 3rd and the 4th post-ovulatory week, earlier than previously thought). Except in selected patients, membrane excision has a high rate of failure and should be abandoned. Cyst-peritoneal shunting avoids the risk of an entrapped fourth ventricle and is presently the best surgical procedure. The overall mortality in this series was 12.5%. Intelligence quotients were over 80 in 60% of the patients. Other studies will be necessary to understand why the communication between the fourth ventricle and the subarachnoid spaces, sufficient in utero, usually becomes insufficient for a normal cerebrospinal fluid (CSF) circulation in the first months following birth. Two hypotheses are discussed: a change in CSF circulation, or bleeding in the dilated fourth ventricle during delivery.

Impulsive Behavior and Recurrent Major Depression Associated with Dandy-Walker Variant

PubMed Central

Kim, Ji Hyun; Kim, Tae Ho; Choi, Young Chil; Chung, Soon-Cheol

2013-01-01

Reported herein is a case of recurrent major depression with impulse control difficulty in a 33-year-old man with Dandy-Walker variant. He was diagnosed as having major depressive disorder a year before he presented himself to the authors' hospital, and had a history of three-time admission to a psychiatric unit in the previous 12 months. He was readmitted and treated with sodium valporate 1,500 mg/day, mirtazapine 45 mg/day, and quetiapine 800 mg/day during the three months that he was confined in the authors' hospital, and the symptoms were reduced within three months but remained thereafter. This is the only case so far reporting recurrent depression with impulse control difficulty associated with Dandy-Walker variant. This case implies that any cerebellar lesion may cause the appearance of recurrent depression with impulse control difficulty in major depressive disorder. PMID:24302956

Syndrome of microcephaly, Dandy-Walker malformation, and Wilms tumor caused by mosaic variegated aneuploidy with premature centromere division (PCD): report of a new case and review of the literature.

PubMed

Kawame, H; Sugio, Y; Fuyama, Y; Hayashi, Y; Suzuki, H; Kurosawa, K; Maekawa, K

1999-01-01

We report a male infant with multiple congenital anomalies and mosaic variegated aneuploidy; a rare cytogenetic abnormality characterized by mosaicism for several different aneuploidies involving many different chromosomes. He had prenatal-onset growth retardation, microcephaly, dysmorphic face, seizures, hypotonia, feeding difficulty, and developmental delay. In addition, he developed bilateral Wilms tumors. Neuroradiological examination revealed Dandy-Walker malformation and hypoplasia of the cerebral hemisphere and pons. Cytogenetic analysis revealed various multiple numerical aneuploidies in blood lymphocytes, fibroblasts, and bone marrow cells, together with premature centromere division (PCD). Peripheral blood chromosome analysis from his parents also showed PCD, but no aneuploid cells. The clinical phenotype and multiple aneuploidies of the patient may be a consequence of the homozygous PCD trait inherited from his parents. Comparison with previously reported cases of multiple aneuploidy suggests that mosaic variegated aneuploidy with PCD may be a clinically recognizable syndrome with major phenotypes being mental retardation, microcephaly, structural brain anomalies (including Dandy-Walker malformation), and possible cancer predisposition.

Neurocutaneous melanosis in association with the Dandy-Walker complex, complicated by melanoma: report of a case and literature review.

PubMed

Mena-Cedillos, Carlos Alfredo; Valencia-Herrera, Adriana M; Arroyo-Pineda, Alma Iris; Salgado-Jiménez, M Angeles; Espinoza-Montero, Rubén; Martínez-Avalos, Armando Bernardo; Perales-Arroyo, Antonio

2002-01-01

Neurocutaneous melanosis is a rare congenital neurocutaneous syndrome in which benign and malignant melanocytic tumors of the leptomeninges with large or numerous congenital melanocytic nevi develop. The Dandy-Walker malformation occurs as a broad posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilation of the fourth ventricle communicating with the posterior fossa. Association of these entities is very unusual and only 10 previous reports were found in the literature. Our patient had multiple, medium-size to small melanocytic nevi present since birth. At 5 years of age the patient has intracranial pressure secondary to hydrocephalus. A diagnosis of Dandy-Walker malformation and suspected neurocutaneous melanosis was established after a skull computed tomography (CT) scan. Three months later the patient developed a right frontal tumor shown on the CT scan. The histologic finding was nevomelanocytic infiltration with strong pleomorphism. The tumor grew rapidly, producing neurogenic shock and death. The postmortem report indicated malignant melanoma.

Atypical psychotic symptoms and Dandy-Walker variant.

PubMed

Williams, Aislinn J; Wang, Zhenni; Taylor, Stephan F

2016-10-01

New-onset psychotic symptoms often respond well to antipsychotic treatment; however, symptoms may be difficult to treat when an underlying brain malformation is present. Here, we present a case of atypical psychotic symptoms in the context of a congenital cerebellar malformation (Dandy-Walker variant). The patient ultimately improved with paliperidone palmitate after multiple antipsychotic medication trials (both oral and one long-acting injectable) were ineffective. Neuroimaging may provide valuable diagnostic and prognostic information in cases of new-onset psychosis with atypical features and treatment resistance, even in the absence of neurologic signs and symptoms.

Congenital Dandy Walker malformation associated with first trimester warfarin: a case report and literature review.

PubMed

Kaplan, L C

1985-12-01

While the warfarin embryopathy is well defined, central nervous system abnormalities associated with gestational warfarin exposure require further definition. Based on the timing of warfarin exposure in humans, it has been proposed that second- and third-trimester exposure predisposes to CNS abnormalities while first-trimester exposure more typically is associated with the warfarin embryopathy. A case is presented of a liveborn male with Dandy Walker malformation, agenesis of the corpus callosum, and Peter anomaly of the right eye who was exposed to warfarin between the 8th and 12th weeks of gestation who had none of the stigmata of the warfarin embryopathy. His is the first known case of exposure confined to the first trimester, and the fifth case of Dandy Walker malformation among a total of 15 CNS cases associated with this drug. This case offers evidence that Dandy Walker malformation may represent a distinct complication of in utero first-trimester exposure, and consideration of these particular abnormalities with exposure limited to a period prior to the known appearance of vitamin K-dependent clotting factors suggests that warfarin has a direct teratogenic effect on central nervous system morphogenesis.

Dandy-Walker malformation: etiologic heterogeneity and empiric recurrence risks.

PubMed

Murray, J C; Johnson, J A; Bird, T D

1985-10-01

The Dandy-Walker malformation (DWM) includes hydrocephalus, incomplete cerebellar vermis and a posterior fossa cyst. Genetic influences and recurrence risks for DWM have not been well characterized. We report a retrospective study of 21 autopsy-proven cases of DWM and review the literature regarding an additional 92 subjects. DWM represents marked genetic and etiologic heterogeneity. Recurrence risk for siblings may be high when DWM is associated with a single gene disorder such as the autosomal recessive Warburg and Meckel-Gruber syndromes. DWM may also result from chromosomal anomalies or environmental factors. When the evidence suggests that DWM has not occurred as part of a Mendelian or chromosomal disorder then the recurrence risk is relatively low (on the order of 1 to 5%). There appears to be an increased frequency of the association of DWM with congenital heart disease, cleft lip/palate and neural tube defects. Based on our study we provide guidelines for the genetic counseling of families having a child with DWM.

Racial disparities in mortality among infants with Dandy-Walker syndrome.

PubMed

Salihu, Hamisu M; Kornosky, Jennifer L; Alio, Amina P; Druschel, Charlotte M

2009-05-01

Congenital malformations are the major cause of infant mortality in the United States, but their contribution to overall racial disparity--a major public health concern--is poorly understood. We sought to estimate the contribution of a congenitally acquired central nervous system lesion, Dandy-Walker Syndrome (DWS), to black-white disparity in infant mortality. Data were obtained from the New York State Congenital Malformations Registry, an ongoing population-based validated surveillance system. We compared black to white infants with respect to infant, neonatal, and postneonatal mortality using Cox proportional hazards regression models. A total of 196 live-born neonates were diagnosed with DWS in the state from 1992 to 2005 inclusive. Of these, 53 were non-Hispanic black and 76 were non-Hispanic white. Neonatal mortality was similar for non-Hispanic blacks and non-Hispanic whites (adjusted hazards ratio [AHR], 1.42; 95% CI, 0.52-3.82), but non-Hispanic blacks had an 8-fold increased risk for postneonatal mortality (AHR, 8.26; 95% CI, 2.08-32.72). Adjustment for fetal growth and other maternal and infant characteristics resulted in a 10-fold increased risk of mortality for non-Hispanic black infants as compared to non-Hispanic whites. By contrast, adjustment for preterm birth attenuated the risk, but non-Hispanic black infants were still more than 6 times as likely to die during the postneonatal period than non-Hispanic whites (AHR, 6.36, 95% CI, 1.52-26.60). DWS has one of the largest black-white disparities in postneonatal survival. This underscores the importance of evaluating racial disparities in infant mortality by specific conditions in order to formulate targeted interventions to reduce disparities.

Severe intellectual disability, West syndrome, Dandy-Walker malformation, and syndactyly in a patient with partial tetrasomy 17q25.3.

PubMed

Hackmann, Karl; Stadler, Anja; Schallner, Jens; Franke, Kathlen; Gerlach, Eva-Maria; Schrock, Evelin; Rump, Andreas; Fauth, Christine; Tinschert, Sigrid; Oexle, Konrad

2013-12-01

We report on a de novo 0.5 Mb triplication (partial tetrasomy) of chromosome 17q25.3 in a 10-year-old girl with severe intellectual disability, infantile seizures (West syndrome), moderate hearing loss, Dandy-Walker malformation, microcephaly, craniofacial dysmorphism, striking cutaneous syndactyly (hands 3-4, feet 2-3), joint laxity, and short stature. The triplication resulted from the unusual combination of a terminal duplication at 17qter and a cryptic translocation of an extra copy of the same segment onto chromosome 10qter. The breakpoint at 17q25.3 was located within the FOXK2 gene. SNP chip analysis suggested that the rearrangement occurred during paternal meiosis involving both paternal chromosomes 17. © 2013 Wiley Periodicals, Inc.

Is Dandy-Walker malformation associated with "distal 13q deletion syndrome"? Findings in a fetus supporting previous observations.

PubMed

Alanay, Yasemin; Aktaş, Dilek; Utine, Eda; Talim, Beril; Onderoğlu, Lütfü; Cağlar, Melda; Tunçbilek, Ergül

2005-07-30

We report on a fetus with a large deletion of the distal part of the long arm of chromosome 13, (del(13)(q14 --> qter)) congenital anomalies of the urinary system, lungs and extremities, and Dandy-Walker malformation (DWM). Although DWM has been associated with many chromosomal abnormalities and genetic syndromes, its relation to the distal 13q has been demonstrated recently. In 2002, McCormack et al., described two patients with deletions of the long arm of chromosome 13 who had multiple congenital abnormalities along with holoprosencephaly (HPE) and DWM. The phenotypic features and autopsy findings of a fetus with "distal 13q deletion syndrome" at 22 weeks gestation are discussed and comparison with the previous two cases is made. The findings support the previous hypothesis suggesting that haploinsufficiency at a locus within 13q22-33 due to microdeletions may be responsible for isolated DWM in some of the patients. Detailed examination of 13q (13q22-33) by means of conventional and molecular cytogenetic methods is necessary in cases with DWM. Copyright 2005 Wiley-Liss, Inc.

Optic nerve coloboma, Dandy-Walker malformation, microglossia, tongue hamartomata, cleft palate and apneic spells: an existing oral-facial-digital syndrome or a new variant?

PubMed

Toriello, Helga V; Lemire, Edmond G

2002-01-01

We report on a female infant with postaxial polydactyly of the hands, preaxial polydactyly of the right foot, cleft palate, microglossia and tongue hamartomata consistent with an oral-facial-digital syndrome (OFDS). The patient also had optic nerve colobomata, a Dandy-Walker malformation, micrognathia and apneic spells. This combination of clinical features has not been previously reported. This patient either expands the clinical features of one of the existing OFDS or represents a new variant. A review of the literature highlights the difficulties in making a specific diagnosis because of the different classification systems that exist in the literature.

Trans-sphenoidal encephalocele in association with Dandy-Walker complex and cardiovascular anomalies.

PubMed

Joy, H M; Barker, C S; Small, J H; Armitage, M

2001-01-01

We present a case of trans-sphenoidal encephalomeningocele in association with a posterior cranial fossa malformation which fulfils the criteria for the Dandy-Walker complex [1]. Congenital cardiovascular defects were also present. An abnormality of neural crest development may be responsible for the combined occurrence of these anomalies.

Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles

PubMed Central

Darbro, Benjamin W.; Mahajan, Vinit B.; Gakhar, Lokesh; Skeie, Jessica M.; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J.; Dobyns, William B.; Kessler, John A.; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J. Robert; Aldinger, Kimerbly A.; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M.; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J.; Bassuk, Alexander G.

2013-01-01

We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles (ADDWOC) and detected a mutation in the extracellular matrix protein encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1 binding partner. Structural modeling the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the extracellular matrix in the pathogenesis of Dandy-Walker spectrum disorders. PMID:23674478

Dandy-Walker malformation and neurocutaneous melanosis in a three-month-old infant

PubMed Central

Mahgoub, Shaza Mohamed; Yassin, Rehab Omer; Osman, Atika Mohamed

2013-01-01

Dandy-Walker Malformation (DWM) is a rare congenital malformation of the brain. It is characterized by cystic enlargement of the fourth ventricle which is communicating with an enlarged posterior fossa, cerebellar dysgenesis, high tentorial insertion and hydrocephalus. Neurocutaneous Melanosis (NCM) is a congenital neurocutaneous syndrome characterized by large or multiple melanocytic nevi and benign or malignant melanocytic tumors of the leptomeninges. We report three months old boy who presented with projectile vomiting associated with a noticeable increase in head size. Several congenital nevi were seen all over his body with evident signs of hydrocephalus. The association of DWM and NCM is a rare complex, and to our knowledge, this is the eleventh case to be reported in the literature. In this article, we discuss the proposed pathogenesis, classification and management of the condition. PMID:27493376

Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles.

PubMed

Darbro, Benjamin W; Mahajan, Vinit B; Gakhar, Lokesh; Skeie, Jessica M; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J; Dobyns, William B; Kessler, John A; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J Robert; Aldinger, Kimerbly A; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J; Bassuk, Alexander G

2013-08-01

We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles and detected a mutation in the extracellular matrix (ECM) protein-encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1-binding partner. Structural modeling of the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the ECM in the pathogenesis of Dandy-Walker spectrum disorders. © 2013 WILEY PERIODICALS, INC.

Neuropsychological Function in a Case of Dandy-Walker Variant in a 68-Year-Old Veteran.

PubMed

Gross, Patricia L; Kays, Jill L; Shura, Robert D

2016-01-01

Dandy-Walker syndrome (DWS) is a congenital brain malformation that is characterized by partial or complete agenesis of the cerebellar vermis and cystic dilatation of the 4th ventricle that shifts ventrolaterally to displace the cerebellar hemispheres. This case is a 68-year-old male veteran with complaints of new-onset cognitive disorder who was found to have previously unsuspected DWS on head computed tomography. This is one of the first case studies to present complete neuropsychological test results in a veteran with DWS. Despite the level of abnormality on imaging, the veteran functioned well until onset of mild cognitive impairments in late adulthood.

[Intravenous Sedation and Repeated "the Same Day General Anesthesia" for a School-age Boy with Dandy-Walker Syndrome and Dentinogenesis].

PubMed

Hitosugi, Takashi; Tsukamoto, Masanori; Fujiwara, Shigeki; Yokoyama, Takeshi

2016-03-01

Dandy-Walker syndrome (DWS) is characterized by perfect or partial defect of the cerebellum vermis and cystic dilatation of the posterior fossa communicating with the fourth ventricle. Common clinical signs are mental retardation, cerebellar ataxia, and those of increased intracranial pressure (ICP). Associated congenital anomalies are craniofacial, cardiac, renal, and skeletal abnormalities. We experienced a case of intravenous sedation and six times of "the same day" general anesthesia for a school-aged boy (10-13 years old) with DWS and hypodentinogenesis. The patient underwent an examination and dental treatments. We had to pay attention to airway management tracheal tube selection and control of ICP. In addition, we should prevent tooth injuries through mishaps during tracheal intubations, since all-tooth-hypoplasia with fragile dental crowns was strongly suggested in this case. Detailed postoperative care is also required for general anesthesia afflicted with DWS.

A case series of 12 patients with incidental asymptomatic Dandy-Walker syndrome and management.

PubMed

Jha, Vikas Chandra; Kumar, Raj; Srivastav, Arun Kumar; Mehrotra, Anant; Sahu, Rabi Narayan

2012-06-01

Incidentally detected asymptomatic Dandy-Walker syndrome (DWS) is sparsely reported in literature at extremes of age (from 1 to 75 years) in association with different diseases. Precipitating factors causing DWS in these cases to manifest in late adulthood are still unidentified. We tried to hypothesize the aetiology and the natural course of disease based on review of literature Twelve cases of asymptomatic DWS were selected retrospectively in this study while being treated for some unrelated disease over a period of 15 years. All the cases had vermian hypoplasia with sizeable fourth ventricular cyst (more than 3 cm), large posterior fossa and with no or borderline ventriculomegaly on CT/MRI. The age ranged from 1 to 65 years. Five cases presented with head injury and four cases presented with enlarged head size with suboccipital protuberance (noticed in children more than 5 years). Remaining cases presented with either occipital encephalocele or right trigeminal neuralgia or fixed atlantoaxial dislocation. They were asymptomatic for DWS following treatment of the presenting complaints on follow-up of average duration of 4.5 years. Presentation at extremes of age signifies that slow degenerative changes in communicating channels between fourth ventricular cyst and surrounding basal cisterns may cause asymptomatic DWS to manifest, but cases having good communication between these structures can remain asymptomatic throughout their life.

A newborn with neurocutaneous melanocytosis and Dandy-Walker malformation.

PubMed

De Cock, Jens; Snauwaert, Julie; Van Rompaey, Walter; Morren, Marie-Anne; Demaerel, Philippe

2014-03-01

Neurocutaneous melanocytosis is a rare congenital dysplasia of the neuroectodermal melanocyte precursor cells that leads to proliferation of melanin-producing cells in the skin and leptomeninges. We describe a newborn with a giant congenital melanocytic nevus on his back, buttocks, and thighs. His brain magnetic resonance imaging study revealed bilateral T1 hyperintense lesions in the cerebellum and in the amygdala, hydrocephalus, and a Blake's pouch cyst, consistent with neurocutaneous melanocytosis and Dandy-Walker malformation. Neurocutaneous melanocytosis has a wide clinical spectrum that includes hydrocephalus, epilepsy, cranial nerve palsy, increased intracranial pressure, and sensorimotor deficits. Copyright © 2014. Published by Elsevier Inc.

Novel SIL1 nonstop mutation in a Chinese consanguineous family with Marinesco-Sjögren syndrome and Dandy-Walker syndrome.

PubMed

Gai, Nan; Jiang, Chen; Zou, Yong-Yi; Zheng, Yu; Liang, De-Sheng; Wu, Ling-Qian

2016-07-01

Marinesco-Sjögren syndrome (MSS) is a rare autosomal recessive disorder, which is characterized by congenital cataracts, cerebellar ataxia, progressive muscle weakness, and delayed psychomotor development. SIL1, which is located at 5q31.2, is the only gene known to cause MSS. Dandy-Walker syndrome (DWS) is defined by hypoplasia, upward rotation of the cerebellar vermis, and cystic dilation of the fourth ventricle; however, its genetic pathogeny remains unclear. Here, we report a Chinese consanguineous family with MSS and DWS. Whole exome sequencing identified a novel nonstop mutation in SIL1. Sanger sequencing revealed that the mutation was segregated in this family according to a recessive mode of inheritance. We found that the mutation changed a stop codon (TGA) to an arginine codon (CGA), and no in-frame termination codon in the 3' untranslated region (UTR) of SIL1 could be found. The mRNA levels of SIL1 were decreased by 56.6% and 37.5% in immortalized lymphoblasts of the patients respectively; the protein levels of SIL1 were substantially decreased. This case study is the first report on Chinese MSS patients, MSS complicated by DWS, and a nonstop mutation in SIL1. Our findings imply the pathogenetic association between DWS and MSS. Copyright © 2016 Elsevier B.V. All rights reserved.

A New Anatomic Variation: Coexistence of Both Dandy-Walker Variant and Ophthalmic Artery Originating From Contralateral Internal Carotid Artery.

PubMed

Ogul, Hayri; Havan, Nuri; Gedikli, Yusuf; Pirimoglu, Berhan; Kantarci, Mecit

2016-06-01

The authors report on 1 patient of variant origin of right ophthalmic artery (OA) from ophthalmic segment of the left internal carotid artery. A 41-year-old man was performed magnetic resonance (MR) imaging and MR angiography. Cerebral MR imaging revealed a Dandy-Walker variant. In MR angiography the authors observed this unusual variant of origin of OA and a complete occlusion of right internal carotid artery. To the authors' knowledge, this is the first patient who has coincidence of both Dandy-Walker variant and origin of OA from contralateral internal carotid artery. Careful observation of MR angiography images with maximum intensity projection is very important for detecting rare vascular variations.

[Focus on Dandy-Walker malformation].

PubMed

Klein, O; Pierre-Kahn, A

2006-09-01

The aim of this review is to summarize our knowledge about Dandy-Walker malformation (DWM) and introduce recent notions about its prognosis. DWM is a malformation associating hypoplasia of the vermis, pseudocystic fourth ventricle, upward displacement of the tentorium, torcular and lateral sinuses and anterio-posterior enlargement of the posterior fossa. It is frequently associated with genetic anomalies, brain malformations (anomalies of gyration, grey matter heterotopias, meningoceles, corpus callosum agenesis...) or systemic malformations (heart, orthopedic, intestinal, urogenital and facial anomalies). It is also part of many syndromes. Its rarity, the difficulty of its diagnosis, the fact that the malformation is mainly known through hospitalized patients, mainly from neurosurgical departments, have made its definition variable and prevents us from having an accurate knowledge of its natural history and prognosis. Hydrocephalus, so frequent in neurosurgical series that some have included it in the definition, is actually rare as has been seen in prenatal series. Treatment, when necessary, is still controversial, the main options remaining cyst fenestration, ventriculo- and/or cystoperitoneal shunts and more recently endoscopic third ventriculostomy. The prognosis, commonly said to be unpredictable, is actually foreseeable after scrutinous observation of the brain anatomy, and mainly of the vermis. A cerebellar vermis with three groups of lobes and two main fissures, as identified on MRI T2 sagittal views, not only has the greatest chance to not be associated with other malformation but also to have a favorable neurocognitive outcome. On the contrary, a deeply dysgenetic vermis with only two or one recognizable lobes is not only constantly associated with other brain malformation but also with poor prognosis. This is a recent advance that may be important for those involved in prenatal counselling.

Neurocutaneous Melanosis in Association with Dandy-Walker Complex with Extensive Intracerebral and Spinal Cord Involvement

PubMed Central

Sung, Kyoung-Su

2014-01-01

Neurocutaneous melanosis (NCM) is a rare congenital syndrome consisting of benign or malignant melanotic tumors of the central nervous system with large or numerous cutaneous melanocytic nevi. The Dandy-Walker complex (DWC) is characterized by an enlarged posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilatation of the fourth ventricle. These each two conditions are rare, but NCM associated with DWC is even more rare. Most patients of NCM with DWC present neurological symptoms early in life such as intracranial hemorrhage, hydrocephalus, and malignant transformation of the melanocytes. We report a 14-year-old male patient who was finally diagnosed as NCM in association with DWC with extensive intracerebral and spinal cord involvement. PMID:25289129

Neonatal carnitine palmitoyltransferase II deficiency associated with Dandy-Walker syndrome and sudden death.

PubMed

Yahyaoui, Raquel; Espinosa, María Gracia; Gómez, Celia; Dayaldasani, Anita; Rueda, Inmaculada; Roldán, Ana; Ugarte, Magdalena; Lastra, Gonzalo; Pérez, Vidal

2011-11-01

Neonatal onset of carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive, often lethal disorder of the mitochondrial beta-oxidation of long-chain fatty acids. It is a rare multiorgan disease which includes hypoketotic hypoglycemia, severe hepatomuscular symptoms, cardiac abnormalities, seizures and lethargy, as well as dysmorphic features. Until now, only 22 affected families have been described in the literature. An increasing number of mutations are being identified in the CPT2 gene, with a distinct genotype-phenotype correlation in most cases. Herein we report a new case of neonatal CPT II deficiency associated with Dandy-Walker syndrome and sudden death at 13 days of life. CPT II deficiency was suggested by acylcarnitine analysis of dried-blood on filter paper in the expanded newborn screening. Genetic analysis of the CPT2 gene identified the presence of a previously described mutation in homozygosity (c.534_558del25bpinsT). All lethal neonatal CPT II deficiency patients previously described presented severe symptoms during the first week of life, although this was not the case in our patient, who remained stable and without apparent vital risk during the first 11 days of life. The introduction of tandem mass spectrometry to newborn screening has substantially improved our ability to detect metabolic diseases in the newborn period. This case illustrates the value of expanded newborn screening in a neonate with an unusual clinical presentation, combining hydrocephalus and sudden death, that might not commonly lead to the suspicion of an inborn error of metabolism. Copyright © 2011 Elsevier Inc. All rights reserved.

Endoscopic transaqueductal placement of a single-catheter cyst-ventriculoperitoneal shunt in a neonate with Dandy-Walker malformation-associated hydrocephalus: case report.

PubMed

Morigaki, Ryoma; Pooh, Kyong-Hon; Nakagawa, Yoshinobu

2011-01-01

A neonate with hydrocephalus associated with Dandy-Walker malformation was successfully treated with an endoscopic placement of a transaqueductal ventricular single catheter. The modified catheter was provided with additional fenestration on its proximal side to allow simultaneous drainage from both the supra- and infratentorial compartments. This technique is well known for isolated fourth ventricles, but has not been applied to hydrocephalus associated with Dandy-Walker malformation. The cyst-ventriculoperitoneal shunt effectively drained both compartments. The patient was doing well 18 months after the surgical procedure. Endoscopic transaqueductal shunt placement can be considered, especially in patients with aqueductal patency.

De novo interstitial deletion of 3q22.3-q25.2 encompassing FOXL2, ATR, ZIC1, and ZIC4 in a patient with blepharophimosis/ptosis/epicanthus inversus syndrome, Dandy-Walker malformation, and global developmental delay.

PubMed

Lim, Byung Chan; Park, Woong Yang; Seo, Eul-Ju; Kim, Ki Joong; Hwang, Yong Seung; Chae, Jong Hee

2011-05-01

We report a case carrying a de novo interstitial deletion of chromosome 3q22-q25. The clinical phenotype of this case included blepharophimosis/ptosis/epicanthus inversus syndrome, Dandy-Walker malformation, and global developmental delay. Contiguous heterozygous deletion of FOXL2, ATR, ZIC1, and ZIC4 was postulated as the causative mechanism of the clinical phenotype. The association of blepharophimosis, ptosis, and epicanthus inversus syndrome with developmental delay or mental retardation may be an indication for the use of brain imaging and chromosomal analysis capable of detecting chromosomal rearrangements encompassing several candidate genes.

Dandy-Walker malformation: analysis of 38 cases.

PubMed

Pascual-Castroviejo, I; Velez, A; Pascual-Pascual, S I; Roche, M C; Villarejo, F

1991-04-01

Thirty-eight cases of Dandy-Walker malformation (DWM) are presented. A female predominance of 3:1 was found. Thirty-two cases (84%) were diagnosed within the 1st year of life. Of these, 17 cases (44.7%) were diagnosed at birth. Ten (26%) were delivered by cesarean section. Thirteen infants (34%) had a birth weight below 3000 g. Several associated malformations were observed, the most frequent being capillary angioma (6 cases); cardiac malformations, ophthalmic anomalies, agenesis of the corpus callosum, malformed limbs, and occipital meningocele were also seen. These observations indicate that DWM represents a disorder of the midline central nervous system indicative of marked genetic and etiologic heterogeneity with the possibility of showing clinical and pathological alterations intra- and extracranially. Macrocephaly was the most frequent physical finding, appearing in 31 cases (82%). Seventeen (44.7%) patients died, 11 before 6 months of age, 3 between 6 and 12 months, and 3 after 1 year. Postmortem studies were performed in 13 patients. Three cases have been lost to follow-up. Mental retardation (IQ below 70) was found in 11 cases (58% of survivors), low intellect (IQ between 70 and 85) in 4, and only 2 patients showed normal intellectual development (IQ more than 85). The high incidence of malformations having several genetic and environmental origins, as well as the high early mortality of patients with DWM, indicate the complexity of this syndrome, which involves the midline developmental field structures. It is not an isolated malformation of the posterior fossa in most cases.

Management of Dandy-Walker complex-associated infant hydrocephalus by combined endoscopic third ventriculostomy and choroid plexus cauterization.

PubMed

Warf, Benjamin C; Dewan, Michael; Mugamba, John

2011-10-01

Dandy-Walker complex (DWC) is a continuum of congenital anomalies comprising Dandy-Walker malformation (DWM), Dandy-Walker variant (DWV), Blake pouch cyst, and mega cisterna magna (MCM). Hydrocephalus is variably associated with each of these, and DWC-associated hydrocephalus has mostly been treated by shunting, often with 2-compartment shunting. There are few reports of management by endoscopic third ventriculostomy (ETV). This study is the largest series of DWC or DWM-associated hydrocephalus treated by ETV, and the first report of treatment by combined ETV and choroid plexus cauterization (ETV/CPC) in young infants with this association. A retrospective review of the CURE Children's Hospital of Uganda clinical database between 2004 and 2010 identified 45 patients with DWC confirmed by CT scanning (25 with DWM, 17 with DWV, and 3 with MCM) who were treated for hydrocephalus by ETV/CPC. Three were excluded because of other potential causes of hydrocephalus (2 postinfectious and 1 posthemorrhagic). The median age at treatment was 5 months (88% of patients were younger than 12 months). There was a 2.4:1 male predominance among patients with DWV. An ETV/CPC (ETV only in one) was successful with no further operations in 74% (mean and median follow-up 24.2 and 20 months, respectively [range 6-65 months]). The rate of success was 74% for DWM, 73% for DWV, and 100% for MCM; 95% had an open aqueduct, and none required posterior fossa shunting. Endoscopic treatment of DWC-associated hydrocephalus should be strongly considered as the primary management in place of the historical standard of creating shunt dependence.

Parenchymal Neurocutaneous Melanosis in Association with Intraventricular Dermoid and Dandy-Walker Variant: A Case Report

PubMed Central

Won, Yoo Dong; Kim, Ki Tae; Chang, Eun Deok; Huh, Pil Woo

2006-01-01

Neurocutaneous melanosis (NCM) is a rare congenital disease that is characterized by the presence of large or multiple congenital melanocytic nevi and melanotic lesions of the central nervous system. We report here on the CT and MR imaging findings of an unusual case of NCM that was associated with intraventricular dermoid and Dandy-Walker malformation. PMID:16799276

Sonographic findings in a case of tetrasomy 9p associated with increased nuchal translucency and Dandy-Walker malformation.

PubMed

Nakamura-Pereira, Marcos; Cima, Luciana Carneiro do; Llerena, Juan Clinton; Guerra, Fernando Antonio Ramos; Peixoto-Filho, Fernando Maia

2009-10-01

We report a case of a 23-year-old pregnant woman, who underwent amniocentesis after ultrasound (US) examination in the first trimester which revealed a nuchal translucency thickness of 2.9 mm. Cytogenetic analysis revealed complete tetrasomy of the short arm of chromosome 9. Further US evaluation in the second trimester revealed Dandy-Walker malformation, ventriculomegaly, bilateral clubfoot, lip and palate clefts, arthrogryposis and hyperechoic kidneys with bilateral pelvic dilatation. At 30 weeks of gestation, a placental abruption was noted and a Cesarean section was performed. The infant died shortly after birth. A review of previous cases of tetrasomy 9p shows that the remarkable sonographic findings are ventriculomegaly, intrauterine growth restriction, genitourinary anomaly, Dandy-Walker malformation, cleft lip/palate and limb malformation, but the association of tetrasomy 9p and increased nuchal translucency had not been reported.

Neurocutaneous melanosis and the Dandy-Walker complex: an uncommon but not so insignificant association.

PubMed

Marnet, Dominique; Vinchon, Matthieu; Mostofi, Keyvan; Catteau, Benoit; Kerdraon, Olivier; Dhellemmes, Patrick

2009-12-01

Neurocutaneous melanosis represents a rare congenital but nonheritable phakomatosis defined as the association of giant or multiple congenital nonmalignant melanocytic nevi with leptomeningeal melanosis or melanoma of the central nervous system. We describe the case of an adolescent with a giant congenital bathing trunk melanocytic nevus who developed progressive intracranial hypertension due to leptomeningeal melanosis confirmed by surgical biopsy. Brain and spine magnetic resonance images showed posterior fossa malformation compatible with the Dandy-Walker complex, hydrocephalus, and extensive enhancement of posterior fossa then spine. Shunt placement, corticotherapy, and chemotherapy were attempted leading to transient relief but the boy died 12 months after the onset of primary neurological symptoms. We discuss diagnosis, pathogenesis, management, and prognosis in the light of data from the recent literature. Neurocutaneous melanosis is considered to follow from neurulation disorders which could account for associated developmental malformations as the so-called Dandy-Walker complex. Cutaneous lesions are usually recognized at birth whereas neurological manifestations develop later. Numerous neurological symptoms have been reported according to extent of leptomeningeal and parenchymal infiltration. Whether magnetic resonance imaging of the neuroaxis represents the choice radiological exam, definite diagnosis relies upon the histological data obtained by mean of biopsy. Once symptomatic, surgical and medical measures remain palliative since death occurs within 3 years.

Interstitial deletion of 8q21-->22 associated with minor anomalies, congenital heart defect, and Dandy-Walker variant.

PubMed

Donahue, M L; Ryan, R M

1995-03-13

We describe an infant with a deletion of 8q21-->22 who had distinct clinical manifestations including minor facial anomalies, a congenital heart defect, a Dandy-Walker variant, and mild to moderate developmental delay. Her facial characteristics included small, wide-spaced eyes, asymmetric bilateral epicanthal folds, a broad nasal bridge, a "carp-shaped" mouth, micrognathia, and prominent, apparently low-set ears. Three other reports describe children with larger proximal deletions of 8q that include 8q21 and q22. These four children all have similar facial appearance. Of the others reported, one had a congenital heart defect and one had craniosynostosis. This case, in addition to the previously noted three cases, helps in delineating a recognizable syndrome.

Ascending transaqueductal cystoventriculoperitoneal shunting in Dandy-Walker malformation: technical note.

PubMed

Unal, Omer Faruk; Aras, Yavuz; Aydoseli, Aydin; Akcakaya, Mehmet Osman

2012-01-01

The optimal treatment for Dandy-Walker malformation is still controversial. Ventriculoperitoneal shunting, cystoperitoneal shunting or combinations are the most common surgical options in the management of this clinical entity. Endoscopic procedures like ventriculocystostomy, 3rd ventriculostomy or endoscopy-assisted shunt surgeries have become the focus of recent publications. We describe a new transcystic endoscopic technique, with the usage of a single ascending transaqueductal shunt catheter with additional holes, whereby both the posterior fossa cyst and supratentorial ventricular compartments are drained effectively. By using this new technique complications associated with combined shunting can be avoided. In addition, by equalizing the pressure within the supra- and infratentorial compartments, the upward or downward herniations associated with single-catheter shunting can be prevented. Copyright © 2013 S. Karger AG, Basel.

Familial Dandy-Walker malformation associated with macrocephaly, facial anomalies, developmental delay, and brain stem dysgenesis: prenatal diagnosis and postnatal outcome in brothers. A new syndrome?

PubMed

Chitayat, D; Moore, L; Del Bigio, M R; MacGregor, D; Ben-Zeev, B; Hodgkinson, K; Deck, J; Stothers, T; Ritchie, S; Toi, A

1994-10-01

Brothers are reported with an apparently new constellation of manifestations including Dandy-Walker complex (DWC), migrational brain disorder, macrocephaly, and facial anomalies. The first brother presented at birth, the second was detected prenatally with DWC and the pregnancy terminated. Fetal brain histopathology showed DWC associated with brainstem dysgenesis. Inheritance is likely autosomal or X-linked recessive. An extensive review of the differential diagnosis of DWC is provided.

AP1S2 is mutated in X-linked Dandy-Walker malformation with intellectual disability, basal ganglia disease and seizures (Pettigrew syndrome).

PubMed

Cacciagli, Pierre; Desvignes, Jean-Pierre; Girard, Nadine; Delepine, Marc; Zelenika, Diana; Lathrop, Mark; Lévy, Nicolas; Ledbetter, David H; Dobyns, William B; Villard, Laurent

2014-03-01

MRXS5 or Pettigrew syndrome was described 20 years ago in a four generation family including nine affected individuals presenting with facial dysmorphism, intellectual disability, Dandy-Walker malformation and inconstant choreoathetosis. Four individuals had iron deposition in the basal ganglia seen on MRI or at autopsy. The mutation causing Pettigrew has remained elusive since the initial description of the condition. We report the identification of a mutation in the X-linked AP1S2 gene in the original Pettigrew syndrome family using X-chromosome exome sequencing. We report additional phenotype details for several of the affected individuals, allowing us to further refine the phenotype corresponding to this X-linked intellectual disability syndrome. The AP1S2 c.426+1 G>T mutation segregates with the disease in the Pettigrew syndrome family and results in loss of 46 amino acids in the clathrin adaptor complex small chain domain that spans most of the AP1S2 protein sequence. The mutation reported here in AP1S2 is the first mutation that is not predicted to cause a premature termination of the coding sequence or absence of the AP1S2 protein. Although most of the families affected by a mutation in AP1S2 were initially described as having different disorders assigned to at least three different OMIM numbers (MIM 300629, 300630 and 304340), our analysis of the phenotype shows that they are all the same syndrome with recognition complicated by highly variable expressivity that is seen within as well as between families and is probably not explained by differences in mutation severity.

The natural history of Dandy-Walker syndrome in the United States: A population-based analysis.

PubMed

McClelland, Shearwood; Ukwuoma, Onyinyechi I; Lunos, Scott; Okuyemi, Kolawole S

2015-01-01

Dandy-Walker syndrome (DWS) is a congenital disorder typically manifesting with hydrocephalus. The classic anatomic hallmarks of DWS are hypoplasia of the cerebellar vermis, anterior-posterior enlargement of the posterior fossa, upward displacement of the torcula and transverse sinuses, and cystic dilatation of the fourth ventricle. Although optimal treatment of DWS typically requires neurosurgical intervention to prevent intracranial pressure increases incompatible with life, the natural history of this disorder has yet to be evaluated on a nationwide level. The Kids' Inpatient Database covering 1997-2003 was used for analysis. Children younger than age 18 admitted for DWS (ICD-9-CM = 742.3) were analyzed with a matched control group. The primary procedure codes for operative CSF drainage were coded into the analysis. The incidence of DWS was 0.136%; 14,599 DWS patients were included. Multiple logistic regression models were used. Odds ratios (OR) were reported with 95% confidence intervals. Mortality (OR = 10.02; P < 0.0001) and adverse discharge disposition (OR = 4.59; P < 0.0001) were significantly greater in DWS patients compared with controls. 20.4% of DWS patients received operative cerebrospinal fluid (CSF) drainage, 81-times more than controls (P < 0.0001). CSF drainage reduced mortality by 44% among DWS patients (P < 0.0001). Although DWS is associated with a 10-fold increase in mortality, operative CSF drainage nearly halves the mortality rate. Based on these findings (Class IIB evidence), it is likely that the increased mortality associated with DWS is directly attributable to the nearly 80% of DWS patients who did not receive operative CSF drainage for hydrocephalus. Consequently, increased access to neurosurgical intervention could reduce the mortality rate of DWS towards that of the general population.

The natural history of Dandy-Walker syndrome in the United States: A population-based analysis

PubMed Central

McClelland, Shearwood; Ukwuoma, Onyinyechi I.; Lunos, Scott; Okuyemi, Kolawole S.

2015-01-01

Background: Dandy-Walker syndrome (DWS) is a congenital disorder typically manifesting with hydrocephalus. The classic anatomic hallmarks of DWS are hypoplasia of the cerebellar vermis, anterior-posterior enlargement of the posterior fossa, upward displacement of the torcula and transverse sinuses, and cystic dilatation of the fourth ventricle. Aims: Although optimal treatment of DWS typically requires neurosurgical intervention to prevent intracranial pressure increases incompatible with life, the natural history of this disorder has yet to be evaluated on a nationwide level. Settings and Design/Materials and Methods: The Kids’ Inpatient Database covering 1997-2003 was used for analysis. Children younger than age 18 admitted for DWS (ICD-9-CM = 742.3) were analyzed with a matched control group. The primary procedure codes for operative CSF drainage were coded into the analysis. The incidence of DWS was 0.136%; 14,599 DWS patients were included. Statistical Analysis Used: Multiple logistic regression models were used. Odds ratios (OR) were reported with 95% confidence intervals. Results and Conclusions: Mortality (OR = 10.02; P < 0.0001) and adverse discharge disposition (OR = 4.59; P < 0.0001) were significantly greater in DWS patients compared with controls. 20.4% of DWS patients received operative cerebrospinal fluid (CSF) drainage, 81-times more than controls (P < 0.0001). CSF drainage reduced mortality by 44% among DWS patients (P < 0.0001). Although DWS is associated with a 10-fold increase in mortality, operative CSF drainage nearly halves the mortality rate. Based on these findings (Class IIB evidence), it is likely that the increased mortality associated with DWS is directly attributable to the nearly 80% of DWS patients who did not receive operative CSF drainage for hydrocephalus. Consequently, increased access to neurosurgical intervention could reduce the mortality rate of DWS towards that of the general population. PMID:25552847

Dandy-Walker malformation and Wisconsin syndrome: novel cases add further insight into the genotype-phenotype correlations of 3q23q25 deletions.

PubMed

Ferraris, Alessandro; Bernardini, Laura; Sabolic Avramovska, Vesna; Zanni, Ginevra; Loddo, Sara; Sukarova-Angelovska, Elena; Parisi, Valentina; Capalbo, Anna; Tumini, Stefano; Travaglini, Lorena; Mancini, Francesca; Duma, Filip; Barresi, Sabina; Novelli, Antonio; Mercuri, Eugenio; Tarani, Luigi; Bertini, Enrico; Dallapiccola, Bruno; Valente, Enza Maria

2013-05-16

The Dandy-Walker malformation (DWM) is one of the commonest congenital cerebellar defects, and can be associated with multiple congenital anomalies and chromosomal syndromes. The occurrence of overlapping 3q deletions including the ZIC1 and ZIC4 genes in few patients, along with data from mouse models, have implicated both genes in the pathogenesis of DWM. Using a SNP-array approach, we recently identified three novel patients carrying heterozygous 3q deletions encompassing ZIC1 and ZIC4. Magnetic resonance imaging showed that only two had a typical DWM, while the third did not present any defect of the DWM spectrum. SNP-array analysis in further eleven children diagnosed with DWM failed to identify deletions of ZIC1-ZIC4. The clinical phenotype of the three 3q deleted patients included multiple congenital anomalies and peculiar facial appearance, related to the localization and extension of each deletion. In particular, phenotypes resulted from the variable combination of three recognizable patterns: DWM (with incomplete penetrance); blepharophimosis, ptosis, and epicanthus inversus syndrome; and Wisconsin syndrome (WS), recently mapped to 3q. Our data indicate that the 3q deletion is a rare defect associated with DWM, and suggest that the hemizygosity of ZIC1-ZIC4 genes is neither necessary nor sufficient per se to cause this condition. Furthermore, based on a detailed comparison of clinical features and molecular data from 3q deleted patients, we propose clinical diagnostic criteria and refine the critical region for WS.

Complete trisomy 9 with unusual phenotypic associations: Dandy-Walker malformation, cleft lip and cleft palate, cardiovascular abnormalities.

PubMed

Tonni, Gabriele; Lituania, Mario; Chitayat, David; Bonasoni, Maria Paola; Keating, Sarah; Thompson, Megan; Shannon, Patrick

2014-12-01

Trisomy 9 is a rare chromosomal abnormality usually associated with first-trimester miscarriage; few fetuses survive until the second trimester. We report two new cases of complete trisomy 9 that both present unusual phenotypic associations, and we analyze the genetic pathway involved in this chromosomal abnormality. The first fetus investigated showed Dandy-Walker malformation, cleft lip, and cleft palate) at the second trimester scan. Cardiovascular abnormalities were characterized by a right-sided, U-shaped aortic arch associated with a ventricular septal defect (VSD). Symmetrical intrauterine growth restriction and multicystic dysplastic kidney disease were associated findings. The second fetus showed a dysmorphic face, bilateral cleft lip, hypoplastic corpus callosum, and a Dandy-Walker malformation. Postmortem examination revealed cardiovascular abnormalities such as persistent left superior vena cava draining into the coronary sinus, membranous ventricular septal defect, overriding aorta, pulmonary valve with two cusps and three sinuses, and the origin of the left subclavian artery distal to the junction of ductus arteriosus and aortic arch. Complete trisomy 9 may result in a wide spectrum of congenital abnormalities, and the presented case series contributes further details on the phenotype of this rare aneuploidy. Copyright © 2014. Published by Elsevier B.V.

Congenital cutis laxa with ligamentous laxity and delayed development, Dandy-Walker malformation and minor heart and osseous defects.

PubMed

Biver, A; De Rijcke, S; Toppet, V; Ledoux-Corbusier, M; Van Maldergem, L

1994-06-01

We present a female infant exhibiting congenital cutis laxa with retardation of growth and motor development, ligamentous laxity and congenital dislocation of the hips. This connective tissue disorder was associated with Dandy-Walker malformation, atrial and ventricular defect and minor bone abnormalities including multiple wormian bones, abnormal tubulation of long bones and absent twelfth pair of ribs. This association is believed to be unique.

Interstitial deletion of 8q21{yields}22 associated with minor anomalies, congenital heart defect, and Dandy-Walker variant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donahue, M.L.; Ryan, R.M.

1995-03-13

We describe an infant with a deletion of 8q21{yields}22 who had distinct clinical manifestations including minor facial anomalies, a congenital heart defect, a Dandy-Walker variant, and mild to moderate developmental delay. Her facial characteristics included small, wide-spaced eyes, asymmetric bilateral epicanthal folds, a broad nasal bridge, a {open_quotes}carp-shaped{close_quotes} mouth, micrognathia, and prominent, apparently low-set ears. Three other reports describe children with larger proximal deletions of 8q that include 8q21 and q22. These four children all have similar facial appearance. Of the others reported, one had a congenital heart defect and one had craniosynostosis. This case, in addition to the previouslymore » noted three cases, helps in delineating a recognizable syndrome. 12 refs., 3 figs., 1 tab.« less

Mortality of Dandy-Walker syndrome in the United States: Analysis by race, gender, and insurance status.

PubMed

McClelland, Shearwood; Ukwuoma, Onyinyechi I; Lunos, Scott; Okuyemi, Kolawole S

2015-01-01

Dandy-Walker syndrome (DWS) is a congenital disorder often diagnosed in early childhood. Typically manifesting with signs/symptoms of increased intracranial pressure, DWS is catastrophic unless timely neurosurgical care can be administered via cerebrospinal fluid (CSF) drainage. The rates of mortality, adverse discharge disposition (ADD), and CSF drainage in DWS may not be uniform regardless of race, gender or insurance status; such differences could reflect disparities in access to neurosurgical care. This study examines these issues on a nationwide level. The Kids' Inpatient Database spanning 1997-2003 was used for analysis. Only patients admitted for DWS (ICD-9-CM = 742.3) were included. Multivariate analysis was adjusted for several variables, including patient age, race, sex, admission type, primary payer, income, and hospital volume. More than 14,000 DWS patients were included. Increasing age predicted reduced mortality (OR = 0.87; P < 0.05), ADD (OR = 0.96; P < 0.05), and decreased likelihood of receiving CSF drainage (OR = 0.86; P < 0.0001). Elective admission type predicted reduced mortality (OR = 0.29; P = 0.0008), ADD (OR = 0.68; P < 0.05), and increased CSF drainage (OR = 2.02; P < 0.0001). African-American race (OR = 1.20; P < 0.05) and private insurance (OR = 1.18; P < 0.05) each predicted increased likelihood of receiving CSF drainage, but were not predictors of mortality or ADD. Gender, income, and hospital volume were not significant predictors of DWS outcome. Increasing age and elective admissions each decrease mortality and ADD associated with DWS. African-American race and private insurance status increase access to CSF drainage. These findings contradict previous literature citing African-American race as a risk factor for mortality in DWS, and emphasize the role of private insurance in obtaining access to potentially lifesaving operative care.

Mortality of Dandy-Walker syndrome in the United States: Analysis by race, gender, and insurance status

PubMed Central

McClelland, Shearwood; Ukwuoma, Onyinyechi I.; Lunos, Scott; Okuyemi, Kolawole S.

2015-01-01

Background: Dandy-Walker syndrome (DWS) is a congenital disorder often diagnosed in early childhood. Typically manifesting with signs/symptoms of increased intracranial pressure, DWS is catastrophic unless timely neurosurgical care can be administered via cerebrospinal fluid (CSF) drainage. The rates of mortality, adverse discharge disposition (ADD), and CSF drainage in DWS may not be uniform regardless of race, gender or insurance status; such differences could reflect disparities in access to neurosurgical care. This study examines these issues on a nationwide level. Materials and Methods: The Kids’ Inpatient Database spanning 1997-2003 was used for analysis. Only patients admitted for DWS (ICD-9-CM = 742.3) were included. Multivariate analysis was adjusted for several variables, including patient age, race, sex, admission type, primary payer, income, and hospital volume. Results: More than 14,000 DWS patients were included. Increasing age predicted reduced mortality (OR = 0.87; P < 0.05), ADD (OR = 0.96; P < 0.05), and decreased likelihood of receiving CSF drainage (OR = 0.86; P < 0.0001). Elective admission type predicted reduced mortality (OR = 0.29; P = 0.0008), ADD (OR = 0.68; P < 0.05), and increased CSF drainage (OR = 2.02; P < 0.0001). African-American race (OR = 1.20; P < 0.05) and private insurance (OR = 1.18; P < 0.05) each predicted increased likelihood of receiving CSF drainage, but were not predictors of mortality or ADD. Gender, income, and hospital volume were not significant predictors of DWS outcome. Conclusion: Increasing age and elective admissions each decrease mortality and ADD associated with DWS. African-American race and private insurance status increase access to CSF drainage. These findings contradict previous literature citing African-American race as a risk factor for mortality in DWS, and emphasize the role of private insurance in obtaining access to potentially lifesaving operative care. PMID:25883477

Dandy-Walker malformation and Wisconsin syndrome: novel cases add further insight into the genotype-phenotype correlations of 3q23q25 deletions

PubMed Central

2013-01-01

Background The Dandy-Walker malformation (DWM) is one of the commonest congenital cerebellar defects, and can be associated with multiple congenital anomalies and chromosomal syndromes. The occurrence of overlapping 3q deletions including the ZIC1 and ZIC4 genes in few patients, along with data from mouse models, have implicated both genes in the pathogenesis of DWM. Methods and results Using a SNP-array approach, we recently identified three novel patients carrying heterozygous 3q deletions encompassing ZIC1 and ZIC4. Magnetic resonance imaging showed that only two had a typical DWM, while the third did not present any defect of the DWM spectrum. SNP-array analysis in further eleven children diagnosed with DWM failed to identify deletions of ZIC1-ZIC4. The clinical phenotype of the three 3q deleted patients included multiple congenital anomalies and peculiar facial appearance, related to the localization and extension of each deletion. In particular, phenotypes resulted from the variable combination of three recognizable patterns: DWM (with incomplete penetrance); blepharophimosis, ptosis, and epicanthus inversus syndrome; and Wisconsin syndrome (WS), recently mapped to 3q. Conclusions Our data indicate that the 3q deletion is a rare defect associated with DWM, and suggest that the hemizygosity of ZIC1-ZIC4 genes is neither necessary nor sufficient per se to cause this condition. Furthermore, based on a detailed comparison of clinical features and molecular data from 3q deleted patients, we propose clinical diagnostic criteria and refine the critical region for WS. PMID:23679990

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity

PubMed Central

Jalali, Ali; Aldinger, Kimberly A.; Chary, Ajit; Mclone, David G.; Bowman, Robin M.; Le, Luan Cong; Jardine, Phillip; Newbury-Ecob, Ruth; Mallick, Andrew; Jafari, Nadereh; Russell, Eric J.; Curran, John; Nguyen, Pam; Ouahchi, Karim; Lee, Charles; Dobyns, William B.; Millen, Kathleen J.; Pina-Neto, Joao M.; Kessler, John A.; Bassuk, Alexander G.

2010-01-01

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnamese-American family identified the ADDWOC causative locus on chromosome 2q36.1 with a multipoint parametric LOD score of 3.3, while haplotype analysis refined the locus to 1.1 Mb. Sequencing of the five known genes in this locus did not identify any protein-altering mutations. However, a terminal deletion of chromosome 2 in a patient with an isolated case of Dandy-Walker malformation also encompassed the 2q36.1 chromosomal region. The Brazilian pedigree did not show linkage to this 2q36.1 region. Taken together, these results demonstrate a locus for ADDWOC on 2q36.1 and also suggest locus heterogeneity for ADDWOC. PMID:18204864

New Lethal Skeletal Dysplasia with Dandy-Walker Malformation, Congenital Heart Defects, Abnormal Thumbs, Hypoplastic Genitalia, and Distinctive Facies

PubMed Central

Stevens, Cathy A.; Lachman, Ralph S.

2011-01-01

We report on two sibs with a lethal form of bone dysplasia with distinctive skeletal findings including rhizomelic and mesomelic limb shortening, hooked clavicles, dumbbell femurs, and absence of talus and calcaneus ossification. Other clinical features include Dandy-Walker malformation, congenital heart defects, joint contractures, genital hypoplasia, and distinctive facial features. These sibs appear to have a previously undescribed skeletal dysplasia, which is most likely inherited in an autosomal recessive fashion. PMID:20602491

MODY3, renal cysts, and Dandy-Walker variants with a microdeletion spanning the HNF1A gene.

PubMed

Matsukura, Hiro; Nagamori, Mariko; Miya, Kazushi; Yorifuji, Tohru

2017-09-01

Heterozygous hepatocyte nuclear factor-1-α gene (HNF1A) mutations are the most common cause of maturity-onset diabetes of the young (MODY), but they rarely involve extrahepatic manifestations. Renal cysts and diabetes syndrome can be caused by HNF1B mutations. No association between MODY3 and Dandy-Walker variants (DWV) has been reported. HNF1A mutations might be responsible for renal malformations. In a Japanese girl with glycosuria, developmental delay, mental retardation, renal cysts, and DWV, the HNF1B gene had no mutations. Array comparative genomic hybridization analysis identified a de-novo interstitial 12q24.22-q24.31 deletion of 5.6 Mb encompassing the HNF1A gene, which is compatible with a diagnosis of MODY3. The variety of phenotypes suggests a novel microdeletion syndrome spanning the HNF1A gene. Because HNF1B functions as an HNF1A/HNF1B heterodimer, haploinsufficient HNF1A interacts with a certain HNF1B haplotype. The resulting truncated heterodimer might engender renal cysts. More patients with well-defined deletion within 12q.24.31 must be evaluated to produce a detailed genotype-phenotype correlation and to elucidate this emerging microdeletion syndrome.
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First-trimester sonographic findings associated with a Dandy-Walker malformation and inferior vermian hypoplasia.

PubMed

Bornstein, Eran; Goncalves Rodríguez, José Luis; Álvarez Pavón, Erika Carolina; Quiroga, Héctor; Or, Drorit; Divon, Michael Y

2013-10-01

We report 2 cases in which first-trimester measurements of the intracranial translucency and the brain stem-to-occipital bone diameter were markedly enlarged. This finding was thought to represent an abnormal fourth ventricle-cisterna magna complex. Subsequently, the diagnoses of a Dandy-Walker malformation with partial vermian agenesis in 1 case and inferior vermian hypoplasia in the other were established and confirmed by either postmortem autopsy or postnatal magnetic resonance imaging. These cases suggest that evaluation of the fourth ventricle-cisterna magna complex, by measuring the intracranial translucency or brain stem-to-occipital bone diameter may identify some cases with structural malformations of the cerebellum as early as the first trimester.

Holoprosencephaly with Dandy-Walker cyst. Rare coexistence of two major malformations.

PubMed

Kurokawa, Y; Tsuchita, H; Sohma, T; Kitami, K; Takeda, T; Hattori, S

1990-01-01

A case of holoprosencephaly associated with Dandy-Walker cyst is reported. The patient was a male baby whose mother had normal serum titers for toxoplasma, syphilis, rubella and hepatitis B. She had no history of diabetes mellitus, administration of drugs or irradiation during the pregnancy. At the 8th month of gestation, fetal hydrocephalus was diagnosed by ultrasonic imaging. He was delivered by caesarean section at 34 weeks and 4 days, weighing 2,644 g. His head circumference was 42 cm; the anterior fontanel was not distended and its tension was normal. The chromosomal karyotype was a normal 46 XY. X-ray CT showed a large dorsal sac cyst in the supratentorial space and a hypoplastic cerebellum with a large cyst in the posterior fossa. He received a cyst-peritoneal shunt 24 days after birth. After this procedure, his head enlargement was arrested. We discuss the etiology of this rare coexistence of two major malformations.

Treatment options for Dandy-Walker malformation.

PubMed

Mohanty, Aaron; Biswas, Arundhati; Satish, Satyanarayana; Praharaj, Shanti Shankar; Sastry, Kolluri V R

2006-11-01

The aim of this study was to assess the efficacy of various treatment options available for children with Dandy-Walker malformation (DWM) and to evaluate the role of endoscopic procedures in the treatment of this disorder. The authors conducted a retrospective review of 72 children who underwent surgical treatment for DWM during a 16-year period. All patients underwent computed tomography scanning, and 26 underwent magnetic resonance (MR) imaging. The initial surgical treatment included ventriculoperitoneal (VP) shunt placement in 21 patients, cystoperitoneal (CP) shunt placement in 24, and combined VP and CP shunt insertion in three. Twenty-one patients underwent endoscopic procedures (endoscopic third ventriculostomy [ETV] alone in 16 patients, ETV with aqueductal stent placement in three, and ETV with fenestration of the occluding membrane in two). Three patients underwent membrane excision via a posterior fossa craniectomy. In the 26 patients who had undergone preoperative MR imaging, aqueductal patency was noted in 23 and aqueductal obstruction in three. These three patients underwent placement of a stent from the third ventricle to the posterior fossa cyst in addition to the ETV procedure. During the follow-up period, 12 patients with a CP shunt and four with a VP shunt experienced shunt malfunctions that required revision. Four patients with a CP shunt also required placement of a VP shunt. In addition, five of the 21 ETVs failed, requiring VP shunt insertion. A reduction in ventricle size noted on postoperative images occurred more frequently in patients with a VP shunt, whereas a reduction in cyst size was more appreciable in patients with a CP shunt. Successful ETV resulted in a slight decrease in ventricle size and varying degrees of reduction in cyst size. Endoscopic procedures may be considered an acceptable alternative in children with DWM. The authors propose a treatment protocol based on preoperative MR imaging findings of associated aqueductal

Successful treatment of Dandy-Walker syndrome by endoscopic third ventriculostomy in a 6-month-old girl with progressive hydrocephalus: a case report and literature review.

PubMed

Hu, Chih-Fen; Fan, Hueng-Chuen; Chang, Cheng-Fu; Wang, Chih-Chien; Chen, Shyi-Jou

2011-02-01

Dandy-Walker syndrome (DWS) is a congenital brain malformation involving the cerebellum and fourth ventricle. We report a 6-month-old girl with DWS presenting an initially normal ventricular system and mild cyst-like lesion over the posterior fossa as assessed by postnatal brain sonography. However, symptoms and signs of increased intracranial cerebral pressure in terms of frequent vomiting and tense anterior fontanel developed, and these were associated with mild hypotonia and poor neck support, and upward-gaze palsy at the age of 6 months. Magnetic resonance imaging revealed a huge cystic lesion of the fourth ventricle, which filled the posterior fossa and ventricular dilatation. The tentorium was progressively displaced upward by the cyst. A nearly complete agenesis of the cerebellar vermis was also confirmed. After a successful endoscopic third ventriculostomy, a series of brain magnetic resonance imaging scans, taken during a follow-up survey, showed normal lateral and third ventricles. Consequently, symptoms of intracranial cerebral pressure resolved, and a developmental milestone was achieved. In conclusion, DWS can be confirmed postpartum, and endoscopic third ventriculostomy was found to be a preferential operative procedure for DWS with hydrocephalus. It may be effective for patients younger than 1 year. Copyright © 2011. Published by Elsevier B.V.

Neurocutaneous melanosis in association with Dandy-Walker malformation: case report and literature review.

PubMed

Schreml, S; Gruendobler, B; Schreml, J; Bayer, M; Ladoyanni, E; Prantl, L; Eichelberg, G

2008-08-01

Neurocutaneous melanosis (NCM) is a rare congenital noninheritable phacomatosis characterized by large and/or numerous cutaneous congenital melanocytic naevi (CMN) in combination with melanocytic leptomeningeal tumours. Dandy-Walker malformation (DWM) consists of a cystic dilatation of the fourth ventricle communicating with the posterior fossa, and a high insertion of the tentorium and hypoplasia/aplasia of the cerebellar vermis (partially caused by Zic1(+/-)Zic 4(+/-) on 3q2). An association of NCM and DWM is very rare, with only 15 previously reported cases to our knowledge. We present an 8-year-old girl with multiple CMN and DWM. A ventriculoperitoneal shunt operation was performed when she was 1 day old. Her neurological symptoms to date comprise headaches, nausea and vomiting as a result of ventriculoperitoneal shunt dislocation at the age of 4 years. The diagnosis is provisional asymptomatic multiple CMN-type NCM in association with DWM.

Adult diagnosed Dandy Walker malformation presenting as an acute brainstem event--a case report and review of the literature.

PubMed

Warwick, C Tanya; Reyes, Bernardo J; Ayoob, M Rose; Subit, Michael

2008-01-01

The Dandy Walker Malformation (DWM) is an infrequent condition seen in pediatric patients. Adult presentation of DWM is extremely rare. This condition usually presents in childhood with hydrocephalus and cerebellar signs and symptoms. This case describes a woman with an undiagnosed DWM who was asymptomatic until the age of 56 when she developed the acute onset of headache, nausea, vomiting, and diplopia. Her history and physical exam were consistent with an acute brainstem infarct. MRI revealed the underlying malformation. The clinical and radiological findings are discussed as well as their implications and possible etiologies.

Dandy-Walker malformations in a case of partial trisomy 9p (p12.1→pter) due to maternal translocation t(9;12)(p12.1;p13.3)

PubMed Central

Vundinti, Babu Rao; Kerketta, Lily; Korgaonkar, Seema; Ghosh, Kanjaksha

2007-01-01

We describe a five-year-old proband presented with Dandy-Walker malformations, right microopthalmia, hamstring contractures, undescended testis with absence of testis in right scrotum in addition to typical trisomy 9p clinical features. Routine cytogenetic studies with GTG - banding showed 46,XY,der(12)t(9;12) (p12;q13.3),mat karyotype (trisomy 9p). Chromosomal analysis of the father was normal and phenotypically normal mother had 46,XX,t(9;12)(p12;q13) karyotype. Fluorescence in situ hybridization analysis with single copy probes bA5OIA2 (9p11.2), bA562M8 (12p12.1) and centromere probes (9) showed break point at 9p12.1 region. The gene dosage effect of Chromosome 9p along with environmental factors might be associated with Dandy- Walker malformations in the patient. PMID:21957340

Phase-based treatment of a complex severely mentally ill case involving complex posttraumatic stress disorder and psychosis related to Dandy Walker syndrome.

PubMed

Mauritz, Maria W; van de Sande, Roland; Goossens, Peter J J; van Achterberg, Theo; Draijer, Nel

2014-01-01

For patients with comorbid complex posttraumatic stress disorder (PTSD) and psychotic disorder, trauma-focused therapy may be difficult to endure. Phase-based treatment including (a) stabilization, (b) trauma-focused therapy, and (c) integration of personality with recovery of connection appears to be the treatment of choice. The objective of this article is to describe and evaluate the therapeutic process of a single case from a holistic perspective. We present a case report of a 47-year-old woman treated for severe complex PTSD resulting from repeated sexual and physical abuse in early childhood and moderate psychotic symptoms stemming from Dandy Walker Syndrome with hydrocephalus. The patient was treated with quetiapine (600-1,000 mg) and citalopram (40 mg). Stabilization consisted of intensive psychiatric nursing care in the home and stabilizing group treatment for complex PTSD. After stabilization, the following symptom domains showed improvement: self-regulation, self-esteem, assertiveness, avoidance of social activities, and negative cognitions. However, intrusions and arousal persisted and were therefore subsequently treated with prolonged imaginary exposure that also included narrative writing assignments and a final closing ritual. This intensive multidisciplinary, phase-based approach proved effective: All symptoms of complex PTSD were in full remission. Social integration and recovery were promoted with the reduction of polypharmacy and the provision of social skills training and lifestyle training. The present case shows a phase-based treatment approach with multidisciplinary collaborative care to be effective for the treatment of a case of complex PTSD with comorbid psychotic disorder stemming from severe neurological impairment. Replication of this promising approach is therefore called for.

Dandy–Walker Malformation, Genitourinary Abnormalities, and Intellectual Disability in Two Families

PubMed Central

Gregor, Anne; Gleeson, Joseph G.; Rosti, Rasim Ozgur

2016-01-01

We report on two families, each with documented consanguinity and two affected with overlapping features of Dandy-Walker malformation, genitourinary abnormalities, intellectual disability, and hearing deficit. This phenotype shares similar findings with many well-known syndromes. However, the clinical findings of this syndrome categorize this as a new syndrome as compared with the phenotype of already established syndromes. Due to parental consanguinity, occurrence in siblings of both genders and the absence of manifestations in obligate carrier parents, an autosomal recessive pattern of inheritance is more likely. The authors believe that these families suggest a novel autosomal recessive cerebello–genital syndrome. Array CGH analyses of an affected did not show pathological deletions or duplications. PMID:26109232

FOXC1 is required for normal cerebellar development and is a major contributor to chromosome 6p25.3 Dandy-Walker malformation

PubMed Central

Aldinger, Kimberly A; Lehmann, Ordan J; Hudgins, Louanne; Chizhikov, Victor V; Bassuk, Alexander G; Ades, Lesley C; Krantz, Ian D; Dobyns, William B; Millen, Kathleen J

2010-01-01

Dandy-Walker malformation (DWM), the most common human cerebellar malformation, has only one characterized associated locus1,2. Here we characterize a second DWM-linked locus on 6p25.3, showing that deletions or duplications encompassing FOXC1 are associated with cerebellar and posterior fossa malformations including cerebellar vermis hypoplasia (CVH), mega-cisterna magna (MCM) and DWM. Foxc1-null mice have embryonic abnormalities of the rhombic lip due to loss of mesenchyme-secreted signaling molecules with subsequent loss of Atoh1 expression in vermis. Foxc1 homozygous hypomorphs have CVH with medial fusion and foliation defects. Human FOXC1 heterozygous mutations are known to affect eye development, causing a spectrum of glaucoma-associated anomalies (Axenfeld-Rieger syndrome, ARS; MIM no. 601631). We report the first brain imaging data from humans with FOXC1 mutations and show that these individuals also have CVH. We conclude that alteration of FOXC1 function alone causes CVH and contributes to MCM and DWM. Our results highlight a previously unrecognized role for mesenchyme-neuroepithelium interactions in the mid-hindbrain during early embryogenesis. PMID:19668217

"Acquired" Dandy-Walker malformation and cerebellar hemorrhage: Usefulness of serial MRI.

PubMed

Pichiecchio, Anna; Decio, Alice; Di Perri, Carol; Parazzini, Cecilia; Rossi, Andrea; Signorini, Sabrina

2016-01-01

Neuroimaging plays a fundamental role in the diagnosis of Dandy Walker malformation (DWM), a posterior fossa anomaly that is usually associated with genetic abnormalities, but may rarely be ascribed to acquired causes. Here, we report the clinical history and neuroimaging studies of a child with a complex cardiac malformation, developmental delay, and oculomotor anomalies whose neuroimaging findings were consistent with an acquired form of DWM. Fetal MRI at gestational weeks 27 and 31 showed cerebellar and vermis hypoplasia and fourth ventricle enlargement, together with hemosiderin deposits on the cerebellar hemispheric surface, but without significant vermian rotation. Postnatal MRIs at 5 days and 13 months revealed progressive counter-clockwise rotation of the hypoplastic cerebellar vermis with cystic dilation of the fourth ventricle, eventually leading to a full-blown DWM. This case strengthens the opinion that DWM is a heterogeneous condition, and may support the hypothesis that acquired meningeal abnormalities in the form of cortico-pial hemosiderosis may play a role in the development of DWM. This case also demonstrates that serial neuroimaging plays a key role in the correct diagnosis of posterior fossa malformations, whose prognosis is difficult to establish on second trimester fetal MRI and requires longer clinical follow-up. Copyright © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Dandy-Walker Malformation: A Clinical and Surgical Outcome Analysis.

PubMed

Bokhari, Iram; Rehman, Lal; Hassan, Sher; Hashim, M Sattar

2015-06-01

To determine the clinical presentations, complications and mortality in patients with Dandy-Walker Malformation (DWM) after surgery i.e., shunt with y-connector. Case series. Neurosurgery Ward, JPMC, Karachi, from January 2009 to December 2013. Cases of DWM, with associated hydrocephalus, further confirmed on CT scan of brain, were admitted through OPD. Those who were previously operated, those with other associated co-morbid or anomalies were excluded from this study. Combined drainage of the ventricular system and posterior fossa cyst, via dual shunt i.e. cystoperitoneal and ventriculoperitoneal shunt with y-connector was performed in all patients. Complications and mortality after surgical intervention in these patients were noted upto one month after surgery. The data analysis for descriptive statistics was done on SPSS version 20. In this study of 70 patients, majority of the patients were female aged between 1 - 2 years. Hydrocephalus was the predominant symptom as being present in all patients, followed by cerebellar signs in 60 (86%), and other in 5 (7.14%) patients. Complications of surgery were infection and shunt fracture dislocation in 7 (10%) each, malpositioning and shunt blockage in 6 (8.5%) each within one month of surgery, intracranial haemorrhage in 5 (7.14%) patients. Only one patient (1.42%) expired after surgical intervention. In DWM, the commonest presentation is that of hydrocephalus. Shunt malfunction and infection are the commonest complication after shunting. Dual shunt with y-connector has the lowest mortality when compared with other methods for treatment of shunt with y-connector.

Hydrocephalus, agenesis of the corpus callosum, and cleft lip/palate represent frequent associations in fetuses with Peters' plus syndrome and B3GALTL mutations. Fetal PPS phenotypes, expanded by Dandy Walker cyst and encephalocele.

PubMed

Schoner, Katharina; Kohlhase, Juergen; Müller, Annette M; Schramm, Thomas; Plassmann, Margit; Schmitz, Ralf; Neesen, Juergen; Wieacker, Peter; Rehder, Helga

2013-01-01

Fetal pathology aims to recognize syndromal patterns of anomalies for goal-directed mutation analyses, genetic counseling, and early prenatal diagnosis in consecutive pregnancies. Here, we report on five fetuses with Peters' plus syndrome (PPS) from two distinct families aborted after prenatal ultrasound diagnosis of hydrocephaly. We performed fetal autopsies and molecular analyses. Among 44 fetuses with prenatally diagnosed hydrocephaly, four fetuses of 16 to 21 gestational weeks presented with additional cleft lip/palate and/or agenesis of the corpus callosum. Other features were growth retardation, hypertelorism, anomalies of the eyes, in part consistent with Peters' anterior chamber anomalies, mild brachymelia, brachydactyly, and also internal anomalies. Suspected PPS was confirmed by detection of B3GALTL mutation in these four fetuses and in one additional sib fetus, revealing homozygosity for the common c.660 + 1G > A donor splice site mutation in intron 8. Autosomal-recessive PPS has not yet been diagnosed prenatally. We want to alert ultrasonographers to the diagnosis of this disorder in growth-retarded fetuses with (recurrent) hydrocephaly, agenesis of the corpus callosum, and cleft lip/palate and stress the more severe fetal manifestation, describing a first such case with additional Dandy-Walker cyst and occult meningoencephalocele. © 2012 John Wiley & Sons, Ltd.

Risk factors for Dandy-Walker malformation: a population-based assessment.

PubMed

Reeder, Matthew R; Botto, Lorenzo D; Keppler-Noreuil, Kim M; Carey, John C; Byrne, Janice L B; Feldkamp, Marcia L

2015-09-01

Dandy-Walker malformation (DWM) is the most common congenital malformation of the cerebellum, but its causes are largely unknown. An increasing number of genes associated with congenital cerebellar malformations have been identified; however, few studies have examined the potential role of non-genetic, potentially modifiable risk factors. From the National Birth Defects Prevention Study, we examined maternal, paternal, and infant characteristics and maternal conditions and periconceptional exposures (from 1 month before to 3 months after conception) among infants with DWM (n = 160) and unaffected controls (n = 10,200), delivered between 1997 and 2009. Odds ratios, crude (cOR) and adjusted (aOR) were computed using logistic regression. Maternal factors associated with DWM included non-Hispanic black race/ethnicity (aOR = 2.0, 95%CI: 1.3-3.2). Among maternal conditions, a history of infertility increased the risk for DWM (all: aOR = 2.4, 95%CI: 1.3-4.6; multiple: aOR = 3.9, 95%CI: 1.7-8.9). The lack of association with many maternal exposures supports the hypothesis of a major contribution of genetic factors to the risk for DWM; however, the observed associations with maternal non-Hispanic black race/ethnicity and maternal history of infertility indicate that further research into factors underlying these characteristics may uncover potentially modifiable risk factors, acting alone or as a component of gene-environment interactions. © 2015 Wiley Periodicals, Inc.

Chromosome 6p25 deletion syndrome: report of a case with optic disc coloboma and review of published ophthalmic findings.

PubMed

Beby, Francis; Des Portes, Vincent; Till, Marianne; Mottolese, Carmine; Denis, Philippe

2012-12-01

The 6p25 deletion syndrome is a rare disorder characterized by Dandy-Walker malformation, congenital heart defects, developmental delay, dysmorphic facial features, and malformations of the anterior segment of the eye with a risk for glaucoma. Here we report a child harboring a cryptic de novo 6p25 deletion, bilateral optic disc coloboma and characteristic anterior segment anomalies. We review reported ophthalmic findings in patients with this syndrome. Retrospective case review of a 4-day-old male with Dandy-Walker malformation and cardiac defects who was referred with a suspected diagnosis of iris coloboma. The ophthalmic examination showed bilateral corectopia associated with posterior embryotoxon. Fundus examination revealed bilateral optic disc excavation, which was diagnosed as colobomatous because of its configuration and stability over time. Because of the association of posterior embryotoxon with Dandy-Walker malformation, a terminal 6p deletion syndrome was clinically suspected. Array comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) studies revealed a 3.2 Mb deletion at 6p25.2p25.3 including the FOXC1 gene. Neither unaffected parent carried this deletion. Optic disc colobomas may be found in patients carrying a 6p25 deletion. This has the potential to confound assessment of affected children for glaucoma and intracranial hypertension.

Ultrasound diagnosis of central nervous system anomalies (bifid choroid plexus, ventriculomegaly, Dandy-Walker malformation) associated with multicystic dysplastic kidney disease in a trisomy 9 fetus: case report with literature review.

PubMed

Tonni, Gabriele; Grisolia, Giampaolo

2013-09-01

Trisomy 9 is a lethal chromosomal abnormality that rarely progresses beyond the second trimester of pregnancy. Multiple central nervous system anomalies, including bifid choroid plexus, ventriculomegaly, and Dandy-Walker malformation, associated with multicystic dysplastic kidney disease in a trisomy 9 fetus are reported. The prenatal ultrasound diagnosis has been aided by novel three-dimensional ultrasound software. Copyright © 2012 Wiley Periodicals, Inc.

Kabuki syndrome: a Chinese case series and systematic review of the spectrum of mutations.

PubMed

Liu, Shuang; Hong, Xiafei; Shen, Cheng; Shi, Quan; Wang, Jian; Xiong, Feng; Qiu, Zhengqing

2015-04-21

Kabuki syndrome is a rare hereditary disease affecting multiple organs. The causative genes identified to date are KMT2D and KDMA6. The aim of this study is to evaluate the clinical manifestations and the spectrum of mutations of KMT2D. We retrospectively retrieved a series of eight patients from two hospitals in China and conducted Sanger sequencing for all of the patients and their parents if available. We also reviewed the literature and plotted the mutation spectrum of KMT2D. The patients generally presented with typical clinical manifestations as previously reported in other countries. Uncommon symptoms included spinal bifida and Dandy-Walker malformation. With respect to the mutations, five mutations were found in five patients, including two frameshift indels, one nonsense mutation and two missense mutations. This is the first case series on Kabuki syndrome in Mainland China. Unusual symptoms, such as spinal bifida and Dandy-Walker syndrome, suggested that neurological developmental defects may accompany Kabuki syndrome. This case series helps broaden the mutation spectrum of Kabuki syndrome and adds information regarding the manifestations of Kabuki syndrome.

Phenotypic outcomes in Mouse and Human Foxc1 dependent Dandy-Walker cerebellar malformation suggest shared mechanisms.

PubMed

Haldipur, Parthiv; Dang, Derek; Aldinger, Kimberly A; Janson, Olivia K; Guimiot, Fabien; Adle-Biasette, Homa; Dobyns, William B; Siebert, Joseph R; Russo, Rosa; Millen, Kathleen J

2017-01-16

FOXC1 loss contributes to Dandy-Walker malformation (DWM), a common human cerebellar malformation. Previously, we found that complete Foxc1 loss leads to aberrations in proliferation, neuronal differentiation and migration in the embryonic mouse cerebellum (Haldipur et al., 2014). We now demonstrate that hypomorphic Foxc1 mutant mice have granule and Purkinje cell abnormalities causing subsequent disruptions in postnatal cerebellar foliation and lamination. Particularly striking is the presence of a partially formed posterior lobule which echoes the posterior vermis DW 'tail sign' observed in human imaging studies. Lineage tracing experiments in Foxc1 mutant mouse cerebella indicate that aberrant migration of granule cell progenitors destined to form the posterior-most lobule causes this unique phenotype. Analyses of rare human del chr 6p25 fetal cerebella demonstrate extensive phenotypic overlap with our Foxc1 mutant mouse models, validating our DWM models and demonstrating that many key mechanisms controlling cerebellar development are likely conserved between mouse and human.

Endoscopic third ventriculostomy with/without choroid plexus cauterization for hydrocephalus due to hemorrhage, infection, Dandy-Walker malformation, and neural tube defect: a meta-analysis.

PubMed

Zandian, Anthony; Haffner, Matthew; Johnson, James; Rozzelle, Curtis J; Tubbs, R Shane; Loukas, Marios

2014-04-01

Endoscopic third ventriculostomy (ETV) is a viable alternative to CSF shunting in hydrocephalic patients and is used with varying degrees of success dependent on age and etiology. The purpose of this meta-analysis is to analyze data on ETV and ETV/CPC (choroid plexus cauterization) outcomes in hopes of providing a clear understanding of their limitations in patients with hydrocephalus due to hemorrhage, infection, Dandy-Walker malformation, or neural tube disorders. An extensive PubMed search dating back 11 years was performed on primary ETV or ETV/CPC procedures for hydrocephalus due to infection, hemorrhage, neural tube defects, and Dandy-Walker malformation. ETV success was defined as no intraoperative or post-operative complications and no need for revision surgery at follow-up. Ten studies were identified for analysis. The data represent 534 patients undergoing primary ETV and 167 patients undergoing primary ETV/CPC. The ETV group reached a 55 % success rate, while the ETV/CPC group reached a 67 % success rate. Success rates of ETV alone for hydrocephalus due to infection, neural tube defects, and intraventricular hemorrhage reached 54, 55, and 57 %, respectively. 84 % success was found in patients older than 2 years of age and 52 % success in patients less than 2 years of age. ETV is a valid treatment for hydrocephalus of any etiology. There exists a small difference in success rates between infection, hemorrhage, and neural tube disorders, though not enough to discount ETV for these etiologies. Initial data utilizing ETV/CPC are promising, and additional studies will need to be done to verify such results.

Phenotypic outcomes in Mouse and Human Foxc1 dependent Dandy-Walker cerebellar malformation suggest shared mechanisms

PubMed Central

Haldipur, Parthiv; Dang, Derek; Aldinger, Kimberly A; Janson, Olivia K; Guimiot, Fabien; Adle-Biasette, Homa; Dobyns, William B; Siebert, Joseph R; Russo, Rosa; Millen, Kathleen J

2017-01-01

FOXC1 loss contributes to Dandy-Walker malformation (DWM), a common human cerebellar malformation. Previously, we found that complete Foxc1 loss leads to aberrations in proliferation, neuronal differentiation and migration in the embryonic mouse cerebellum (Haldipur et al., 2014). We now demonstrate that hypomorphic Foxc1 mutant mice have granule and Purkinje cell abnormalities causing subsequent disruptions in postnatal cerebellar foliation and lamination. Particularly striking is the presence of a partially formed posterior lobule which echoes the posterior vermis DW 'tail sign' observed in human imaging studies. Lineage tracing experiments in Foxc1 mutant mouse cerebella indicate that aberrant migration of granule cell progenitors destined to form the posterior-most lobule causes this unique phenotype. Analyses of rare human del chr 6p25 fetal cerebella demonstrate extensive phenotypic overlap with our Foxc1 mutant mouse models, validating our DWM models and demonstrating that many key mechanisms controlling cerebellar development are likely conserved between mouse and human. DOI: http://dx.doi.org/10.7554/eLife.20898.001 PMID:28092268

Dandy-Walker Syndrome

MedlinePlus

... Strategy Current Research Research Funded by NINDS Basic Neuroscience Clinical Research Translational Research Research at NINDS Focus ... Diversity Resources Jobs at NINDS Director, Division of Neuroscience Director, NIH BRAIN Initiative® Health Scientist Administrator Channels ...

Syringomyelia caused by an arachnoid web in a patient with shunted Dandy-Walker malformation.

PubMed

Lee, Hee Chang; Choi, Jung Won; Lee, Ji Yeoun; Phi, Ji Hoon; Kim, Seung-Ki; Cho, Byung-Kyu; Wang, Kyu-Chang

2017-04-01

Dandy-Walker malformation (DWM) is a congenital brain anomaly characterized by dysgenesis of the cerebellar vermis and the presence of a posterior fossa cyst. The association of syringomyelia with DWM is extremely rare. A 10-year-old patient who was diagnosed with DWM in infancy presented with progressive scoliosis and fecal incontinence. He had been treated with cystoventriculoperitoneal shunting with a Y-connection during infancy, which was followed by a revision 6 years later. During the revision surgery, intraventricular bleeding occurred and was managed conservatively. Imaging studies for the current visit revealed syringomyelia along the cervicothoracic spinal cord and a membranous structure around the cervicomedullary junction. Phase-contrast cine magnetic resonance imaging (MRI) revealed disturbed cerebrospinal fluid (CSF) flow across the membrane. We excised the arachnoid web that was tethering the brainstem and blocking CSF flow. Postoperatively, the patient experienced symptom relief, and the follow-up imaging study demonstrated a dramatic decrease in the size of the syringomyelia. We suggest that syrinx formation in this patient was possibly caused by disturbed CSF flow and tethering of the brainstem. We experienced an unusual case of DWM with syringomyelia which was caused by an arachnoid web blocking CSF flow and tethering the brainstem. The arachnoid web seems to be formed by previous bleeding which occurred at the time of shunt revision. After excision of the arachnoid web, the patient showed good outcome.

A rare case of giant occipital meningocele with Dandy Walker Syndrome: Can it grow bigger than this?

PubMed Central

Mankotia, Dipanker Singh; Satyarthee, Guru Dutta; Singh, Bhoopendra; Sharma, Bhawani Shankar

2016-01-01

Association of Dandy–Walker syndrome with occipital meningocele (OMC) is extremely rare and about thirty cases are reported till date in the Western literature. However, OMC is classified by Talamonti et al. into small, large, and giant categories with respective diameters were upto 5 cm in small, large with 5–9 cm, and giant with >9 cm. Usually the size of OMC progressively increases as raised intracranial pressure leads to compensatory cerebrospinal fluid escape into sac with the growth of children. Authors report an interesting case of an 18-month-old female child with extra-gigantic OMC, whose size was almost same since birth, representing the first case of its kind, who underwent successful surgical repair. Clinical presentation, radiological features, and surgical management options in literature are reviewed briefly for this rare disease association. PMID:28217162

Genetics Home Reference: Walker-Warburg syndrome

MedlinePlus

... also involved in development of this condition. The proteins produced from the genes listed above and others involved in Walker-Warburg syndrome modify a protein called alpha (α)-dystroglycan; this modification, called glycosylation, ...

Prenatal diagnosis of Joubert syndrome

PubMed Central

Zhu, Lingling; Xie, Limei

2017-01-01

Abstract Introduction: Joubert syndrome (JS) is a rare autosomal recessive inherited disease belonging to ciliopathy with the causative mutation of genes. Except for X-linked inheritance, the high recurrence rate of a family is about 25%. After birth, it may cause a series of neurological symptoms, even with retina, kidney, liver, and other organ abnormalities, which is defined as Joubert syndrome and related disorders (JSRD). Molecular genetics research contributes to disease prediction and genetic counseling. Prenatal diagnosis is rare. Magnetic resonance imaging (MRI) is usually the first-choice diagnostic modality with typical brain images characterized by the molar tooth sign. We describe a case of JS prenatally and Dandy-Walker malformation for the differential diagnosis based on ultrasonograms. We also review the etiology, imaging features, clinical symptoms, and diagnosis of JSRD. Case presentation: A 22-year-old woman was pregnant at 27 1/7 weeks’ gestation with fetal cerebellar vermis hypoplasia. Fetal ultrasonography and MRI confirmed a diagnosis of JS at our center. The couple finally opted to terminate the fetus, which had a normal appearance and growth parameters. The couple also had an AHI1 gene mutation on chromosome 6. Conclusions: Currently, a diagnosis of JS is commonly made after birth. Fewer cases of prenatal diagnosis by ultrasonography have been made, and they are more liable to be misdirected because of some nonspecial features that also manifest in Dandy-Walker malformation, cranio-cerebello-cardiac syndrome, and so on. PMID:29390414

Goldston syndrome in a fetus: case report and literature review.

PubMed

Avcu, Serhat; Akdeniz, Hüseyin; Unal, Ozkan; Kurdoğlu, Mertihan

2010-01-01

We present a case of the Goldston syndrome which is the association of polycystic kidneys with Dandy-Walker malformation. The diagnosis was made by ultrasound in twenty second week of gestation. Obstetric ultrasound and fetal MRI studies showed hydrocephalus, agenesis of the cerebellar hemispheres, vermian hypoplasia, cystic dilatation of the 4(th) ventricle, enlargement of the posterior fossa, abdominal distension, and oligohydramnios.. The kidneys were symmetrically enlarged and multicystic. To our knowledge this is the third reported case of Goldston syndrome which was diagnosed during intrauterine life.

PHACE syndrome: new views on diagnostic criteria.

PubMed

Poetke, M; Frommeld, T; Berlien, H P

2002-12-01

The association of large facial hemangiomas with posterior fossa malformations and vascular anomalies has been termed the PHACE syndrome. It is characterized by the association of posterior fossa malformations, hemangiomas, arterial anomalies, coarctation of the aorta and other cardiac defects, and eye abnormalities. Since most articles focus on isolated case reports, an extended retrospective literature review of all reports of large hemangiomas with associated abnormalities of the central nervous system and other malformations was performed to examine the clinical features, and other not as yet reported associated anomalies. Reports were found on 59 patients with PHACE syndrome, to which we added ten cases of our own. The Dandy-Walker syndrome is the most common CNS abnormality reported in association with PHACE syndrome and was seen in 48 (81 %) patients. Arterial malformations were found in 13 (22 %) cases; only 11 patients (19 %) had structural arterial abnormalities without associated Dandy-Walker complex. As published, about one third of patients (31 %) had further ophthalmologic abnormalities, and cardiac anomalies, including coarctation of the aorta. Subglottic hemangiomas were seen in 4 (7 %) patients and ventral developmental defects also in 3 cases. In seven of 59 patients (12 %) with PHACE syndrome, intracranial hemangiomas were present. This study demonstrates that among other CNS abnormalities, special attention should be given to intracranial hemangiomas which seems to be a peculiar phenotype of PHACE syndrome. We therefore suggest that a sixth criterion should be added to the five minimal inclusion criteria for PHACE syndrome. The inclusion criteria would then be: arterial abnormalities or/and intracranial hemangiomas. On the basis of our experience with our patients and with those previously reported, we stress the importance of using contrast-enhanced imaging to detect intracranial lesions.

PHACES syndrome associated with carcinoid endobronchial tumor.

PubMed

Mama, Nadia; H'mida, Dorra; Lahmar, Imen; Yacoubi, Mohamed Tahar; Tlili-Graiess, Kalthoum

2014-05-01

PHACES syndrome consists of the constellation of manifestations including posterior fossa anomalies of the brain (most commonly Dandy-Walker malformations), hemangiomas of the face and scalp, arterial abnormalities, cardiac defects, eye anomalies and sternal defects. We present a case with a possible PHACES syndrome including sternal cleft and supraumbilical raphé, precordial skin tag, persistent left superior vena cava and subtle narrowing of the aorta with an endobronchial carcinoid tumor. All these anomalies were discovered on chest multi-detector CT. This is a unique case of PHACES syndrome associated with carcinoid tumor. Review of the literature revealed 3 cases of PHACES syndrome with glial tumor. The authors tried to find the relationship between PHACES syndrome and carcinoid tumors or gliomas, which all derive from the neural crest cells.

Perioperative management of a patient with Dandy Walker malformation with tetralogy of Fallot undergoing total correction and fresh homologous pericardial pulmonary valve conduit implantation: Report of a rare case.

PubMed

Datt, Vishnu; Tempe, D K; Lalwani, Parin; Aggarwal, Saket; Kumar, Pradeep; Diwakar, Anitha; Tomar, A S

2015-01-01

Perioperative management of a patient with Dandy-Walker malformation (DWM) with tetralogy of Fallot (TOF), patent ductus arteriosus, and pulmonary artery stenosis is a great challenge to the anesthesiologist. Anesthetic management in such patients can trigger tet spells that might rapidly increase intracranial pressure (ICP), conning and even death. The increase in ICP can precipitate tet spells and further brain hypoxia. To avoid an increase in ICP during TOF corrective surgery ventriculo-peritoneal (VP) shunt should be performed before cardiac surgery. We present the first case report of a 11-month-old male baby afflicted with DWM and TOF who underwent successful TOF total corrective surgery and fresh autologous pericardial pulmonary valve conduit implantation under cardiopulmonary bypass after 1 week of VP shunt insertion.

Sutures - separated

MedlinePlus

The problem may be caused by: Arnold-Chiari malformation Battered child syndrome Bleeding inside the brain (intraventricular hemorrhage) Brain tumor Certain vitamin deficiencies Dandy-Walker malformation Down syndrome Hydrocephalus Infections that are ...

DOORS syndrome: phenotype, genotype and comparison with Coffin-Siris syndrome.

PubMed

Campeau, Philippe M; Hennekam, Raoul C

2014-09-01

DOORS syndrome (Deafness, Onychodystrophy, Osteodystrophy, mental Retardation, Seizures) is characterized mainly by sensorineural deafness, shortened terminal phalanges with small nails of hands and feet, intellectual deficiency, and seizures. Half of the patients with all clinical features have mutations in TBC1D24. We review here the manifestations of patients clinically diagnosed with DOORS syndrome. In this cohort of 32 families (36 patients) we detected 13 individuals from 10 families with TBC1D24 mutations. Subsequent whole exome sequencing in the cohort showed the same de novoSMARCB1 mutation (c.1130G>A), known to cause Coffin-Siris syndrome, in two patients. Distinguishing features include retinal anomalies, Dandy-Walker malformation, scoliosis, rocker bottom feet, respiratory difficulties and absence of seizures, and 2-oxoglutaric aciduria in the patients with the SMARCB1 mutation. We briefly discuss the heterogeneity of the DOORS syndrome phenotype and the differential diagnosis of this condition. © 2014 Wiley Periodicals, Inc.

Prenatal diagnosis of Joubert syndrome: A case report and literature review.

PubMed

Zhu, Lingling; Xie, Limei

2017-12-01

Joubert syndrome (JS) is a rare autosomal recessive inherited disease belonging to ciliopathy with the causative mutation of genes. Except for X-linked inheritance, the high recurrence rate of a family is about 25%. After birth, it may cause a series of neurological symptoms, even with retina, kidney, liver, and other organ abnormalities, which is defined as Joubert syndrome and related disorders (JSRD). Molecular genetics research contributes to disease prediction and genetic counseling. Prenatal diagnosis is rare. Magnetic resonance imaging (MRI) is usually the first-choice diagnostic modality with typical brain images characterized by the molar tooth sign. We describe a case of JS prenatally and Dandy-Walker malformation for the differential diagnosis based on ultrasonograms. We also review the etiology, imaging features, clinical symptoms, and diagnosis of JSRD. A 22-year-old woman was pregnant at 27 1/7 weeks' gestation with fetal cerebellar vermis hypoplasia. Fetal ultrasonography and MRI confirmed a diagnosis of JS at our center. The couple finally opted to terminate the fetus, which had a normal appearance and growth parameters. The couple also had an AHI1 gene mutation on chromosome 6. Currently, a diagnosis of JS is commonly made after birth. Fewer cases of prenatal diagnosis by ultrasonography have been made, and they are more liable to be misdirected because of some nonspecial features that also manifest in Dandy-Walker malformation, cranio-cerebello-cardiac syndrome, and so on. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Cystic kidneys in fetal Walker-Warburg syndrome with POMT2 mutation: Intrafamilial phenotypic variability in four siblings and review of literature.

PubMed

Nabhan, Marwa M; ElKhateeb, Nour; Braun, Daniela A; Eun, Sungho; Saleem, Sahar N; YungGee, Heon; Hildebrandt, Friedhelm; Soliman, Neveen A

2017-10-01

Walker-Warburg syndrome (WWS) is a severe form of congenital muscular dystrophy secondary to α-dystroglycanopathy with muscle, brain, and eye abnormalities often leading to death in the first weeks of life. It is transmitted in an autosomal recessive pattern, and has been linked to at least 15 different genes; including protein O-mannosyltransferase 1 (POMT1), protein O-mannosyltransferase 2 (POMT2), protein O-mannose beta-1,2-N acetylglucosaminyltransferase (POMGNT1), fukutin (FKTN), isoprenoid synthase domain-containing protein (ISPD), and other genes. We report on a consanguineous family with four consecutive siblings affected by this condition with lethal outcome in three (still birth), and termination of the fourth pregnancy based on antenatal MRI identification of brain and kidney anomalies that heralded proper and deep clinical phenotyping. The diagnosis of WWS was suggested based on the unique collective phenotype comprising brain anomalies in the form of lissencephaly, subcortical/subependymal heterotopia, and cerebellar hypoplasia shared by all four siblings; microphthalmia in one sibling; and large cystic kidneys in the fetus and another sibling. Other unshared neurological abnormalities included hydrocephalus and Dandy-Walker malformation. Whole exome sequencing of the fetus revealed a highly conserved missense mutation in POMT2 that is known to cause WWS with brain and eye anomalies.In conclusion, the heterogeneous clinical presentation in the four affected conceptions with POMT2 mutation expands the current clinical spectrum of POMT2-associated WWS to include large cystic kidneys; and confirms intra-familial variability in terms of brain, kidney, and eye anomalies. © 2017 Wiley Periodicals, Inc.

Subtelomeric deletions of chromosome 6p: molecular and cytogenetic characterization of three new cases with phenotypic overlap with Ritscher-Schinzel (3C) syndrome.

PubMed

Descipio, Cheryl; Schneider, Lori; Young, Terri L; Wasserman, Nora; Yaeger, Dinah; Lu, Fengmin; Wheeler, Patricia G; Williams, Marc S; Bason, Lynn; Jukofsky, Lori; Menon, Ammini; Geschwindt, Ryan; Chudley, Albert E; Saraiva, Jorge; Schinzel, Albert A G L; Guichet, Agnes; Dobyns, William E; Toutain, Annick; Spinner, Nancy B; Krantz, Ian D

2005-04-01

We have identified six children in three families with subtelomeric deletions of 6p25 and a recognizable phenotype consisting of ptosis, posterior embryotoxon, optic nerve abnormalities, mild glaucoma, Dandy-Walker malformation, hydrocephalus, atrial septal defect, patent ductus arteriosus, and mild mental retardation. There is considerable clinical overlap between these children and individuals with the Ritscher-Schinzel (or cranio-cerebello-cardiac (3C)) syndrome (OMIM #220210). Clinical features of 3C syndrome include craniofacial anomalies (macrocephaly, prominent forehead and occiput, foramina parietalia, hypertelorism, down-slanting palpebral fissures, ocular colobomas, depressed nasal bridge, narrow or cleft palate, and low-set ears), cerebellar malformations (variable manifestations of a Dandy-Walker malformation with moderate mental retardation), and cardiac defects (primarily septal defects). Since the original report, over 25 patients with 3C syndrome have been reported. Recessive inheritance has been postulated based on recurrence in siblings born to unaffected parents and parental consanguinity in two familial cases. Molecular and cytogenetic mapping of the 6p deletions in these three families with subtelomeric deletions of chromosome 6p have defined a 1.3 Mb minimally deleted critical region. To determine if 6p deletions are common in 3C syndrome, we analyzed seven unrelated individuals with 3C syndrome for deletions of this region. Three forkhead genes (FOXF1 and FOXQ1 from within the critical region, and FOXC1 proximal to this region) were evaluated as potential candidate disease genes for this disorder. No deletions or disease-causing mutations were identified.

Cancer Management in Kabuki Syndrome: The First Case of Wilms Tumor and a Literature Review.

PubMed

Teranishi, Hideto; Koga, Yuhki; Nakashima, Kentaro; Morihana, Eiji; Ishii, Kanako; Sakai, Yasunari; Taguchi, Tomoaki; Oda, Yoshinao; Miyake, Noriko; Matsumoto, Naomichi; Ohga, Shouichi

2018-02-27

A 3-year-old Japanese girl treated for hypoplastic left heart syndrome and Dandy-Walker syndrome was diagnosed with Kabuki syndrome (KS) with a mutation of KMT2D; c.13285C>T:p.Q4429*. Concurrently, macrohematuria portended the diagnosis of Wilms tumor. Postoperative chemotherapy has achieved complete remission despite a prolonged and reduced regimen due to liver dysfunction and convulsions. Cancer predisposition has been suggested for KS due to oncogenic mutations in KMT2D or KDM6A. The first case of nephroblastoma exemplified the treatability of malignancies in KS patients, as shown in the 9 cases reviewed. Active screening and intervention are recommended for the cure of malignancy in KS children.

A deletion in the VLDLR gene in Eurasier dogs with cerebellar hypoplasia resembling a Dandy-Walker-like malformation (DWLM).

PubMed

Gerber, Martina; Fischer, Andrea; Jagannathan, Vidhya; Drögemüller, Michaela; Drögemüller, Cord; Schmidt, Martin J; Bernardino, Filipa; Manz, Eberhard; Matiasek, Kaspar; Rentmeister, Kai; Leeb, Tosso

2015-01-01

Dandy-Walker-like malformation (DWLM) is the result of aberrant brain development and mainly characterized by cerebellar hypoplasia. DWLM affected dogs display a non-progressive cerebellar ataxia. Several DWLM cases were recently observed in the Eurasier dog breed, which strongly suggested a monogenic autosomal recessive inheritance in this breed. We performed a genome-wide association study (GWAS) with 9 cases and 11 controls and found the best association of DWLM with markers on chromosome 1. Subsequent homozygosity mapping confirmed that all 9 cases were homozygous for a shared haplotype in this region, which delineated a critical interval of 3.35 Mb. We sequenced the genome of an affected Eurasier and compared it with the Boxer reference genome and 47 control genomes of dogs from other breeds. This analysis revealed 4 private non-synonymous variants in the critical interval of the affected Eurasier. We genotyped these variants in additional dogs and found perfect association for only one of these variants, a single base deletion in the VLDLR gene encoding the very low density lipoprotein receptor. This variant, VLDLR:c.1713delC is predicted to cause a frameshift and premature stop codon (p.W572Gfs*10). Variants in the VLDLR gene have been shown to cause congenital cerebellar ataxia and mental retardation in human patients and Vldlr knockout mice also display an ataxia phenotype. Our combined genetic data together with the functional knowledge on the VLDLR gene from other species thus strongly suggest that VLDLR:c.1713delC is indeed causing DWLM in Eurasier dogs.

Hydromyelia

MedlinePlus

... children with hydrocephalus or birth defects such as Chiari Malformation II and Dandy-Walker syndrome. Syringomyelia, however, features ... primarily in adults, the majority of whom have Chiari Malformation type 1 or have experienced spinal cord trauma. ...

Diagnosis of Van den Ende-Gupta syndrome: Approach to the Marden-Walker-like spectrum of disorders.

PubMed

Niederhoffer, Karen Y; Fahiminiya, Somayyeh; Eydoux, Patrice; Mawson, John; Nishimura, Gen; Jerome-Majewska, Loydie A; Patel, Millan S

2016-09-01

Marden-Walker syndrome is challenging to diagnose, as there is significant overlap with other multi-system congenital contracture syndromes including Beals congenital contractural arachnodactyly, D4ST1-Deficient Ehlers-Danlos syndrome (adducted thumb-clubfoot syndrome), Schwartz-Jampel syndrome, Freeman-Sheldon syndrome, Cerebro-oculo-facio-skeletal syndrome, and Van den Ende-Gupta syndrome. We discuss this differential diagnosis in the context of a boy from a consanguineous union with Van den Ende-Gupta syndrome, a diagnosis initially confused by the atypical presence of intellectual disability. SNP microarray and whole exome sequencing identified a homozygous frameshift mutation (p.L870V) in SCARF2 and predicted damaging mutations in several genes, most notably DGCR2 (p.P75L) and NCAM2 (p.S147G), both possible candidates for this child's intellectual disability. We review distinguishing features for each Marden-Walker-like syndrome and propose a clinical algorithm for diagnosis among this spectrum of disorders. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Syndromes, disorders and maternal risk factors associated with neural tube defects (VII).

PubMed

Chen, Chih-Ping

2008-09-01

Neural tube defects (NTDs) may be associated with syndromes, disorders and maternal risk factors. This article provides a comprehensive review of the syndromes, disorders and maternal risk factors associated with NTDs, including DK phocomelia syndrome (von Voss-Cherstvoy syndrome), Siegel-Bartlet syndrome, fetal warfarin syndrome, craniotelencephalic dysplasia, Czeizel-Losonci syndrome, maternal cocaine abuse, Weissenbacher- Zweymller syndrome, parietal foramina (cranium bifidum), Apert syndrome, craniomicromelic syndrome, XXagonadism with multiple dysraphic lesions including omphalocele and NTDs, Fryns microphthalmia syndrome, Gershoni-Baruch syndrome, PHAVER syndrome, periconceptional vitamin B6 deficiency, and autosomal dominant Dandy-Walker malformation with occipital cephalocele. NTDs associated with these syndromes, disorders and maternal risk factors are a rare but important cause of NTDs. The recurrence risk and the preventive effect of maternal folic acid intake in NTDs associated with syndromes, disorders and maternal risk factors may be different from those of nonsyndromic multifactorial NTDs. Perinatal diagnosis of NTDs should alert doctors to the syndromes, disorders and maternal risk factors associated with NTDs, and prompt thorough etiologic investigation and genetic counseling.

Appearance of fetal posterior fossa at 11-14 weeks in fetuses with Dandy-Walker malformation or chromosomal anomalies.

PubMed

Volpe, P; Contro, E; Fanelli, T; Muto, B; Pilu, G; Gentile, M

2016-06-01

To describe the sonographic appearance of fetal posterior fossa anatomy at 11-14 weeks of pregnancy and to assess the outcome of fetuses with increased intracranial translucency (IT) and/or brainstem-to-occipital bone (BSOB) diameter. Reference ranges for brainstem (BS), IT and cisterna magna (CM) measurements, BSOB diameter and the BS : BSOB ratio were obtained from the first-trimester ultrasound examination of 233 fetuses with normal postnatal outcome (control group). The intraobserver and interobserver variability of measurements were investigated using 73 stored ultrasound images. In addition, a study group of 17 fetuses with increased IT and/or BSOB diameter was selected to assess outcome. No significant intraobserver or interobserver variability was found for any measurement in the control group. In the study group, IT was increased in all cases and BSOB diameter was above the 95(th) centile of the calculated normal range in all but two (88%) cases. In 13/17 study cases, only two of the three posterior brain spaces were recognized on ultrasound. These 13 fetuses had a larger BSOB diameter than did the four cases that showed all three posterior brain spaces, and had severe associated anomalies including Dandy-Walker malformation (DWM) and/or chromosomal anomalies. Visualization of the fetal posterior fossa anatomy at 11-14 weeks' gestation is feasible. Increased fluid in the posterior brain at 11-14 weeks, particularly in the case of non-visibility of the septation that divides the future fourth ventricle from the CM, is an important risk factor for cystic posterior fossa malformations, in particular DWM, and/or chromosomal aberrations. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Ritscher-Schinzel cranio-cerebello-cardiac (3C) syndrome: report of four new cases and review.

PubMed

Leonardi, M L; Pai, G S; Wilkes, B; Lebel, R R

2001-08-15

Ritscher-Schinzel syndrome, also known as the 3C syndrome, is a rare, autosomal recessive syndrome characterized by craniofacial, cerebellar, and cardiac anomalies. Cardiac manifestations include ventricular septal defect, atrial septal defect, tetralogy of Fallot, double outlet right ventricle, hypoplastic left heart, aortic stenosis, pulmonic stenosis and other valvular anomalies. Central nervous system anomalies include Dandy-Walker malformation, cerebellar vermis hypoplasia and enlargement of the cisterna magna. Craniofacial abnormalities seen are cleft palate, ocular coloboma, prominent occiput, low-set ears, hypertelorism, down-slanting palpebral fissures, depressed nasal bridge and micrognathia. Dandy-Walker malformation, posterior fossa cyst, hydrocephalus and congenital heart defect are common malformations that may occur in isolation or as a part of many syndromes. Accurate genetic diagnosis and counseling require detailed analysis of the external as well as the internal anatomy and knowledge of the relative frequencies of various malformations in syndromes that may have overlapping clinical signs. We have had the opportunity recently to study four cases of the Ritscher-Schinzel syndrome. A review of all reported cases is presented and an attempt made to define the minimum diagnostic criteria for the Ritscher-Schinzel syndrome. Of the nine craniofacial anomalies commonly reported as a part of the Ritscher-Schinzel syndrome, we consider two i.e., cleft palate and ocular coloboma, to be readily and objectively ascertainable. The other seven craniofacial traits, however, are somewhat subjective, require expert interpretation and are sometimes difficult to ascertain in a newborn or stillborn fetus. These are prominent forehead, prominent occiput, hypertelorism, down-slanting palpebral fissures, low-set ears, depressed nasal bridge and micrognathia. At least four of these were present in all cases that had a secure diagnosis of the Ritscher-Schinzel syndrome

Dandy–Walker Variant with Schizophrenia: Comorbidity or Cerebellar Cognitive Affective Syndrome?

PubMed Central

Sinha, Pallavi; Tarwani, Jatin; Kumar, Pankaj; Garg, Amit

2017-01-01

Dandy–Walker complex (DWC) is a series of neurodevelopmental anomalies involving the posterior cranial fossa. The cerebellum has long been considered to be involved in motor coordination and balance. However, it has now been noted to play an important role in higher order cognitive, emotional, and behavioral functions. The concept of cerebellar cognitive affective syndrome, describing a coherent spectrum of cognitive and behavioral disturbances in adults following cerebellar damage has long been proposed. There have been reported cases of co-occurring psychiatric symptoms and DWC in literature, but the conclusive evidence for an association between the same remains lacking. Herein, we report a case of schizophrenia presenting along with Dandy–Walker Variant. PMID:28515557

Inferior Cerebellar Hypoplasia Resembling a Dandy-Walker-Like Malformation in Purebred Eurasier Dogs with Familial Non-Progressive Ataxia: A Retrospective and Prospective Clinical Cohort Study

PubMed Central

Bernardino, Filipa; Rentmeister, Kai; Schmidt, Martin J.; Bruehschwein, Andreas; Matiasek, Kaspar; Matiasek, Lara A.; Lauda, Alexander; Schoon, Heinz A.; Fischer, Andrea

2015-01-01

Cerebellar malformations can be inherited or caused by insults during cerebellar development. To date, only sporadic cases of cerebellar malformations have been reported in dogs, and the genetic background has remained obscure. Therefore, this study`s objective was to describe the clinical characteristics, imaging features and pedigree data of a familial cerebellar hypoplasia in purebred Eurasier dogs. A uniform cerebellar malformation characterized by consistent absence of the caudal portions of the cerebellar vermis and, to a lesser degree, the caudal portions of the cerebellar hemispheres in association with large retrocerebellar fluid accumulations was recognized in 14 closely related Eurasier dogs. Hydrocephalus was an additional feature in some dogs. All dogs displayed non-progressive ataxia, which had already been noted when the dogs were 5 – 6 weeks old. The severity of the ataxia varied between dogs, from mild truncal sway, subtle dysmetric gait, dysequilibrium and pelvic limb ataxia to severe cerebellar ataxia in puppies and episodic falling or rolling. Follow-up examinations in adult dogs showed improvement of the cerebellar ataxia and a still absent menace response. Epileptic seizures occurred in some dogs. The association of partial vermis agenesis with an enlarged fourth ventricle and an enlarged caudal (posterior) fossa resembled a Dandy-Walker-like malformation in some dogs. Pedigree analyses were consistent with autosomal recessive inheritance. PMID:25668516

Multiple developmental programs are altered by loss of Zic1 and Zic4 to cause Dandy-Walker malformation cerebellar pathogenesis

PubMed Central

Blank, Marissa C.; Grinberg, Inessa; Aryee, Emmanuel; Laliberte, Christine; Chizhikov, Victor V.; Henkelman, R. Mark; Millen, Kathleen J.

2011-01-01

Heterozygous deletions encompassing the ZIC1;ZIC4 locus have been identified in a subset of individuals with the common cerebellar birth defect Dandy-Walker malformation (DWM). Deletion of Zic1 and Zic4 in mice produces both cerebellar size and foliation defects similar to human DWM, confirming a requirement for these genes in cerebellar development and providing a model to delineate the developmental basis of this clinically important congenital malformation. Here, we show that reduced cerebellar size in Zic1 and Zic4 mutants results from decreased postnatal granule cell progenitor proliferation. Through genetic and molecular analyses, we show that Zic1 and Zic4 have Shh-dependent function promoting proliferation of granule cell progenitors. Expression of the Shh-downstream genes Ptch1, Gli1 and Mycn was downregulated in Zic1/4 mutants, although Shh production and Purkinje cell gene expression were normal. Reduction of Shh dose on the Zic1+/−;Zic4+/− background also resulted in cerebellar size reductions and gene expression changes comparable with those observed in Zic1−/−;Zic4−/− mice. Zic1 and Zic4 are additionally required to pattern anterior vermis foliation. Zic mutant folial patterning abnormalities correlated with disrupted cerebellar anlage gene expression and Purkinje cell topography during late embryonic stages; however, this phenotype was Shh independent. In Zic1+/−;Zic4+/−;Shh+/−, we observed normal cerebellar anlage patterning and foliation. Furthermore, cerebellar patterning was normal in both Gli2-cko and Smo-cko mutant mice, where all Shh function was removed from the developing cerebellum. Thus, our data demonstrate that Zic1 and Zic4 have both Shh-dependent and -independent roles during cerebellar development and that multiple developmental disruptions underlie Zic1/4-related DWM. PMID:21307096

The Battle for Richard Lapointe's Life.

ERIC Educational Resources Information Center

Perske, Robert

1996-01-01

This narrative describes the case of Richard Lapointe, a man with Dandy-Walker syndrome (a congenital brain malformation resulting in a build-up of cerebrospinal fluid in the skull), who was accused of homicide. The questionable practices of the police in acquiring a confession are recounted. The narrative discusses the court appeals process and…

The Typology and Function of Private Speech in a Young Man with Intellectual Disabilities: An Empirical Case Study

ERIC Educational Resources Information Center

Lechler, Suzanne; Hare, Dougal Julian

2015-01-01

A naturalistic observational single case study was carried out to investigate the form and function of private speech (PS) in a young man with Dandy-Walker variant syndrome and trisomy 22. Video recordings were observed, transcribed and coded to identify all combinations of type and form of PS. Through comparison between theories of PS and the…

[Fetal malformations and chromosome abnormalities diagnosed at the Center of Prenatal Diagnosis of the University of Aquila in the 1995-1998 triennium].

PubMed

Carta, G; Iovenitti, P; D'Alfonso, A; Mascaretti, G; Moscarini, M

1999-10-01

Over the past few years numerous techniques have been developed, allowing an evaluation of fetal physiopathology that was unthinkable until recently. The authors describe 20 cases of fetal malformations and chromosomal abnormalities diagnosed by scan and amniocentesis at the Centre for Diagnosis and Obstetric Prophylaxis at L'Aquila University. Between January 1995 and April 1998 a total of 1180 amniocentesis and 4000 obstetric scans were performed in a group of 1650 pregnant women. Of the patients examined using ultrasound scan, 8 presented manifest fetal pathologies, of which 5 were associated with chromosome abnormalities: 1) left ventricular hypoplasia, common atrium, tricuspid dysplasia; 2) omphalocele; 3) Morgagni-Stewart-Morel syndrome; 4) plurilobate cystic hygroma; 5) duodenal atresia; 6) Dandy-Walker syndrome; 7) cystic hygroma and hydrops; 8) cystic hygroma, hydrops, cardiopathy and Dandy-Walker syndrome. Among the pregnant women undergoing amniocentesis without a prior diagnosis of fetal malformation, 12 presented pathological fetal karyotypes: 2 cases of Turner's syndrome; 2 cases of Edward's syndrome; 2 cases of Klinefelter's syndrome, of deletion of a stretch of chromosome 8; 1 case of Down's syndrome; 2 cases of supernumerary marker chromosome; 1 twin pregnancy with Klinefelter's syndrome in one twin and paracentric inversion of chromosome 13 in the other; 1 twin pregnancy with a small supernumerary marker chromosome in both twins. Ultrasonography often enables the diagnosis of congenital abnormalities not associated with chromosome pathologies. However, karyotype studies play an essential role in pregnancies with a high genetic risk.

[A phenotypic description of 26 patients with Ritscher-Schinzel syndrome (cranio-cerebello-cardiac dysplasia or 3C syndrome)].

PubMed

Pira-Paredes, S M; Montoya-Villada, J H; Franco-Restrepo, J L; Moncada-Velez, M; Cornejo, J W

2017-06-01

Ritscher-Schinzel syndrome (also known as cranio-cerebello-cardiac dysplasia or 3C syndrome) is a rare genetic syndrome that is mainly characterised by the association of cardiac and craniofacial anomalies together with others affecting the posterior fossa. We report on 26 patients with Ritscher-Schinzel syndrome at a hospital in Medellin, in the Department of Antioquia, Colombia. Males account for 69% of this cohort. The mean age of the cohort was 30 months, and 42% were under the age of one year at the time of diagnosis. All of them presented ocular disorders, and megalocornea was the most frequent ocular manifestation (69%), whereas low-set ears (80.7%) and septal heart defects (68.7%) were the most common facial and cardiac malformations, respectively. The most frequent malformations of the posterior fossa were megacisterna magna (31.8%) and Dandy-Walker malformation (27%). 84% of the cases had delayed neurodevelopment or intellectual disability. Skeletal manifestations were frequent: the group consisting of camptodactyly, single palmar crease, overlapping fingers, vertical talus and nail hypoplasia were found in hands and feet in 96% of the cases. Ritscher-Schinzel syndrome is a heterogeneous syndrome from the genetic and clinical point of view. These results suggest that the skeletal and ocular abnormalities that were observed can facilitate the phenotypic diagnosis. However, it is necessary to conduct further studies that allow us to gain a deeper knowledge of its prevalence and help identify other genes involved in this syndrome.

Extensive intracranial calcification of pseudo-TORCH syndrome with features of Dandy–Walker malformation

PubMed Central

Patnaik, Ashis; Mishra, Sudhansu Sekhar; Das, Srikanta

2017-01-01

Pseudo-TORCH syndrome or congenital infection-like syndrome is a group of conditions which resemble congenital infections such as those caused by toxoplasmosis, rubella, cytomegalovirus (CMV), herpes (TORCH) group of organisms, clinico-radiologically, but serological tests are negative for the organisms. One of the variety shows features such as microcephaly, extensive intracranial calcification showing gross resemblance to congenital CMV infection, making its other name as microcephaly intracranial calcification syndrome (MICS). Dandy–Walker malformation (DWM), in addition to posterior fossa large cyst, cerebellar vermis hypoplasia, and hydrocephalus is often associated with agenesis of the corpus callosum and callosal lipomas, dysplasia of the brainstem, and cerebellar hypoplasia or dysgenesis. But radiological features of DWM with microcephaly and intracranial calcification are very unusual and have been rarely reported in the literature.[1] We report a case of infant showing clinical features suggestive of congenital CMV infection with negative serology and radiological imaging suggestive of DWM with extensive intracranial calcification. Pseudo-TORCH syndrome with radiological features of DWM is a congenital developmental abnormality. Inspite of hydrocephalus, it does not require cerebrospinal fluid (CSF) diversionary procedure due to lack of increased intracranial pressure. Conservative management for seizure disorder is the optimal therapy. PMID:28761539

Slit ventricle syndrome and early-onset secondary craniosynostosis in an infant

PubMed Central

Ryoo, Hyun Gee; Kim, Seung-Ki; Cheon, Jung-Eun; Lee, Ji Yeoun; Wang, Kyu-Chang; Phi, Ji Hoon

2014-01-01

Patient: Female, 14 months Final Diagnosis: Slit ventricle syndrome Symptoms: Hydrocephalus • lethargy and seizure • vomiting Medication: — Clinical Procedure: — Specialty: Pediatrics and Neonatology Objective: Challenging differential diagnosis Background: Shunt surgery is a common solution for hydrocephalus in infancy. Slit ventricle syndrome and secondary craniosynostosis are late-onset complications after shunt placement; these 2 conditions occasionally occur together. Case Report: We report a case of early-onset secondary craniosynostosis with slit ventricle syndrome after shunt surgery in an infant, which led to a catastrophic increase in intracranial pressure (ICP). A 4-month-old girl with a Dandy-Walker malformation underwent a ventriculoperitoneal shunt procedure. Her head circumference (HC) gradually decreased to approximately the 5th percentile for her age group after shunt surgery. Seven months later, she developed increased ICP symptoms and underwent a shunt revision with a diagnosis of shunt malfunction. Her symptoms were temporarily relieved, but she repeatedly visited the emergency room (ER) for the same symptoms and finally collapsed, with an abrupt increase in ICP, 3 months later. Further evaluation revealed the emergence of sagittal synostosis at 7 months after initial shunt surgery. After reviewing all clinical data, slit ventricle syndrome combined with secondary craniosynostosis was diagnosed. Emergent cranial expansion surgery with shunt revision was performed, and the increased ICP signs subsided in the following days. Conclusions: Clinical suspicion and long-term HC monitoring are important in the diagnosis of slit ventricle syndrome and secondary craniosynostosis after shunt surgery, even in infants and young children. PMID:24944727

Agile Walker.

PubMed

Katz, Reuven

2015-01-01

The goal of the Agile Walker is to improve the outdoor mobility of healthy elderly people with some mobility limitations. It is a newly developed, all-terrain walker, equipped with an electric drive system and speed control that can assists elderly people to walk outdoors or to hike. The walker has a unique product design with an attractive look that will appeal to "active-agers" population. This paper describes product design requirements and the development process of the Agile Walker, its features and some preliminary testing results.

Walker's Eleodes (Coleoptera: Tenebrionidae)

USDA-ARS?s Scientific Manuscript database

The type specimens of five species of Eleodes described by Francis Walker were studied in order to establish their true identity. The synonymy of Eleodes convexicollis Walker and Eleodes conjunctus Walker with E. obscurus (Say); that of Eleodes latiusculus Walker with E. humeralis LeConte; and that ...

Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families†

PubMed Central

Chang, Wendy; Winder, Thomas L.; LeDuc, Charles A.; Simpson, Lynn L.; Millar, William S.; Dungan, Jeffrey; Ginsberg, Norman; Plaga, Stacey; Moore, Steven A.; Chung, Wendy K.

2009-01-01

Objective Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of α-dystroglycan (α-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS. Method We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis. Results We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults. Conclusion These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population. PMID:19266496

Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families.

PubMed

Chang, Wendy; Winder, Thomas L; LeDuc, Charles A; Simpson, Lynn L; Millar, William S; Dungan, Jeffrey; Ginsberg, Norman; Plaga, Stacey; Moore, Steven A; Chung, Wendy K

2009-06-01

Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of alpha-dystroglycan (alpha-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS. We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis. We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults. These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population. Copyright (c) 2009 John Wiley & Sons, Ltd.

The role of Harvey Cushing and Walter Dandy in the evolution of modern neurosurgery in the Netherlands, illustrated by their correspondence.

PubMed

Groen, Rob J M; Koehler, Peter J; Kloet, Alfred

2013-03-01

The development of modern neurosurgery in the Netherlands, which took place in the 1920s, was highly influenced by the personal involvement of both Harvey Cushing and Walter Dandy, each in his own way. For the present article, the authors consulted the correspondence (kept at the Cushing/Whitney Medical Library in New Haven and the Alan Mason Chesney Medical Archives in Baltimore) of Cushing and Dandy with their Dutch disciples. The correspondence provides a unique inside view into the minds of both neurosurgical giants. After the neurologist Bernard Brouwer had paved the way for sending the Dutch surgeon Ignaz Oljenick overseas, Cushing personally took the responsibility to train him (1927-1929). On his return to Amsterdam, Oljenick and Brouwer established the first neurosurgical department in the country. Encouraged by Oljenick's favorable results, a number of Dutch general surgeons started asking Cushing for support. Cushing strategically managed and deflected these requests, probably aiming to increase the advantage of Oljenick and Brouwer. However, the University Hospital in Groningen persisted in the plans to establish its own neurosurgical unit and sent Ferdinand Verbeek to the US in 1932. Although staying at Cushing's department initially, Verbeek ultimately applied to Walter Dandy for a position of visiting voluntary assistant, staying until the end of 1934. Verbeek and Dandy became lifelong friends. On his return to Groningen, Verbeek started practicing neurosurgery, isolated in the northern part of the country. He relied on the support of Dandy, with whom he kept up a regular correspondence, discussing cases and seeking advice. Dandy, on his part, used Verbeek as the ambassador in Europe for his operative innovations. At the beginning of World War II, Oljenick had to flee the country, which concluded the direct line with the Cushing school in the Netherlands. After Dandy's death (1946), Verbeek continued practicing neurosurgery following his style and

Cancer-prone syndrome of mosaic variegated aneuploidy and total premature chromatid separation: report of five infants.

PubMed

Kajii, T; Ikeuchi, T; Yang, Z Q; Nakamura, Y; Tsuji, Y; Yokomori, K; Kawamura, M; Fukuda, S; Horita, S; Asamoto, A

2001-11-15

Five infants (two girls and three boys) from four families all had severe pre- and postnatal growth retardation, profound developmental delay, microcephaly, hypoplasia of the brain with Dandy-Walker complex or other posterior fossa malformations, and developed uncontrollable clonic seizures. Four infants developed Wilms tumors, and one showed cystic lesions in bilateral kidneys. All five infants showed variegated mosaic aneuploidy in cultured lymphocytes. In two infants whose chromosomes were prepared by us, 48.5%-83.2% lymphocytes showed total premature chromatid separation (PCS). Their parents had 3.5%-41.7% of their lymphocytes in total PCS. The remaining three infants and their parents, whose chromosomes were prepared at outside laboratories, tended to show lower frequencies of total PCS. Another five infants reported with the disorder were reviewed together with the five infants we described. Together, their clinical and cytogenetic manifestations were similar enough to suggest a syndrome. Seven of the 10 infants developed proven or probable Wilms tumors. The age at diagnosis of the tumors was younger than usual at 2-16 months. The tumors were bilateral in four infants and unilateral in three infants, and cystic changes were present in six infants. Two infants developed botryoid rhabdomyosarcoma. The carriers of the syndrome are thus liable to tumorigenesis. The possible role of mitotic checkpoint defects, proven in two infants with the syndrome (Matsuura et al. [2000: Am J Hum Genet 69:483-486]), was discussed in connection with tumor development and progression. Copyright 2001 Wiley-Liss, Inc.

The neurosurgeon as baseball fan and inventor: Walter Dandy and the batter's helmet.

PubMed

Brewster, Ryan; Bi, Wenya Linda; Smith, Timothy R; Gormley, William B; Dunn, Ian F; Laws, Edward R

2015-07-01

Baseball maintains one of the highest impact injury rates in all athletics. A principal causative factor is the "beanball," referring to a pitch thrown directly at a batter's head. Frequent morbidities elicited demand for the development of protective gear development in the 20th century. In this setting, Dr. Walter Dandy was commissioned to design a "protective cap" in 1941. His invention became widely adopted by professional baseball and inspired subsequent generations of batting helmets. As a baseball aficionado since his youth, Walter Dandy identified a natural partnership between baseball and medical practice for the reduction of beaning-related brain injuries. This history further supports the unique position of neurosurgeons to leverage clinical insights, inform innovation, and expand service to society.

Walter E. Dandy: his contributions to pituitary surgery in the context of the overall Johns Hopkins Hospital experience

PubMed Central

Corsello, Andrea; Di Dalmazi, Giulia; Pani, Fabiana; Chalan, Paulina; Salvatori, Roberto

2017-01-01

Background Walter E. Dandy (1886–1946) was an outstanding neurosurgeon who spent his entire career at the Johns Hopkins Hospital. After graduating from medical school in 1910, he completed a research fellowship in the Hunterian laboratory with Harvey Cushing and then joined the Department of Surgery as resident, rising to the rank professor in 1931. Dandy made several contributions that helped building the neurosurgical specialty, most famously the introduction of pneumo-ventriculography to image brain lesions for which he received a Nobel prize nomination. He also performed many pituitary surgeries, although his role in this area is less known and overshadowed by that of Cushing’s. Purpose This retrospective cohort study was designed to unveil Dandy’s pituitary work and place it in the context of the overall pituitary surgeries performed at the Johns Hopkins Hospital. Methods Pituitary surgery data were obtained by screening the paper and electronic surgical pathology records of the Department of Pathology, as well as the general operating room log books of the Johns Hopkins Hospital housed in the Chesney Medical Archives. Results A total of 3211 pituitary surgeries associated with a pathological specimen were performed between February 1902 and July 2017 in 2847 patients. Most of the surgeries (2875 of 3211 89%) were done by 21 neurosurgeons. Dandy ranks 4th as number of surgeries, with 287 pituitary operations in 35 years of activity. He averaged 8 pituitary surgeries per year, a rate that positions him 6th among all Hopkins neurosurgeons. With the exception of his first operation done in July 1912 while Cushing was still at Hopkins, Dandy approached the pituitary gland transcranially, rather than transphenoidally. The majority of Dandy’s pituitary patients had a pathological diagnosis of pituitary adenomas, followed by craniopharyngiomas and sellar cysts. In the decades Dandy operated, pituitary surgeries represented 0.56% of the total Johns Hopkins

Injuries associated with infant walkers.

PubMed

2001-09-01

In 1999, an estimated 8800 children younger than 15 months were treated in hospital emergency departments in the United States for injuries associated with infant walkers. Thirty-four infant walker-related deaths were reported from 1973 through 1998. The vast majority of injuries occur from falls down stairs, and head injuries are common. Walkers do not help a child learn to walk; indeed, they can delay normal motor and mental development. The use of warning labels, public education, adult supervision during walker use, and stair gates have all been demonstrated to be insufficient strategies to prevent injuries associated with infant walkers. To comply with the revised voluntary standard (ASTM F977-96), walkers manufactured after June 30, 1997, must be wider than a 36-in doorway or must have a braking mechanism designed to stop the walker if 1 or more wheels drop off the riding surface, such as at the top of a stairway. Because data indicate a considerable risk of major and minor injury and even death from the use of infant walkers, and because there is no clear benefit from their use, the American Academy of Pediatrics recommends a ban on the manufacture and sale of mobile infant walkers. If a parent insists on using a mobile infant walker, it is vital that they choose a walker that meets the performance standards of ASTM F977-96 to prevent falls down stairs. Stationary activity centers should be promoted as a safer alternative to mobile infant walkers.

Magnetic Resonance Imaging of Malformations of Midbrain-Hindbrain.

PubMed

Abdel Razek, Ahmed Abdel Khalek; Castillo, Mauricio

2016-01-01

We aim to review the magnetic resonance imaging appearance of malformations of midbrain and hindbrain. These can be classified as predominantly cerebellar malformations, combined cerebellar and brain stem malformations, and predominantly brain stem malformations. The diagnostic criteria for the majority of these morphological malformations are based on neuroimaging findings. The predominantly cerebellar malformations include predominantly vermian hypoplasia seen in Dandy-Walker malformation and rhombencephalosynapsis, global cerebellar hypoplasia reported in lissencephaly and microlissencephaly, and unilateral cerebellar hypoplasia seen in PHACES, vanishing cerebellum, and cerebellar cleft. Cerebellar dysplasias are seen in Chudley-McCullough syndrome, associated with LAMA1 mutations and GPR56 mutations; Lhermitte-Duclos disease; and focal cerebellar dysplasias. Cerebellar hyperplasias are seen in megalencephaly-related syndromes and hemimegalencephaly with ipsilateral cerebellomegaly. Cerebellar and brain stem malformations include tubulinopathies, Joubert syndrome, cobblestone malformations, pontocerebellar hypoplasias, and congenital disorders of glycosylation type Ia. Predominantly brain stem malformations include congenital innervation dysgenesis syndrome, pontine tegmental cap dysplasia, diencephalic-mesencephalic junction dysplasia, disconnection syndrome, and pontine clefts.

Water Budgets of the Walker River Basin and Walker Lake, California and Nevada

USGS Publications Warehouse

Lopes, Thomas J.; Allander, Kip K.

2009-01-01

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. The only outflow from Walker Lake is evaporation from the lake surface. Between 1882 and 2008, upstream agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-feet. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes streamflow in the Walker River basin and an updated water budget of Walker Lake with emphasis on the lower Walker River basin downstream from Wabuska, Nevada. Water budgets are based on average annual flows for a 30-year period (1971-2000). Total surface-water inflow to the upper Walker River basin upstream from Wabuska was estimated to be 387,000 acre-feet per year (acre-ft/yr). About 223,000 acre-ft/yr (58 percent) is from the West Fork of the Walker River; 145,000 acre-ft/yr (37 percent) is from the East Fork of the Walker River; 17,000 acre-ft/yr (4 percent) is from the Sweetwater Range; and 2,000 acre-ft/yr (less than 1 percent) is from the Bodie Mountains, Pine Grove Hills, and western Wassuk Range. Outflow from the upper Walker River basin is 138,000 acre-ft/yr at Wabuska. About 249,000 acre-ft/yr (64 percent) of inflow is diverted for irrigation, transpired by riparian vegetation, evaporates from lakes and reservoirs, and recharges alluvial aquifers. Stream losses in Antelope, Smith, and Bridgeport Valleys are due to evaporation from reservoirs and agricultural diversions with negligible stream infiltration or riparian evapotranspiration. Diversion rates in Antelope and Smith Valleys were estimated to be 3.0 feet per year (ft/yr) in each valley. Irrigated fields receive an additional 0.8 ft of precipitation, groundwater pumpage, or both for a total applied-water rate

Distribution of elements in the Salt Wash member of the Morrison Formation in the Jo Dandy area, Montrose County, Colorado

USGS Publications Warehouse

Newman, William L.; Elston, Donald P.

1957-01-01

A study of the distribution of elements in the Salt Wash member of the Morrison formation of Jurassic age from samples taken in the Jo Dandy area, Montrose County, Colo., was made to determine average chemical composition of mudstone and sandstone and to determine the magnitude of variations in concentrations of elements within similar rock types. Analytical data were obtained by semiquantitative spectrographic and radiometric methods. Results of the study show that variations in concentrations of about 20 elements commonly detected by semiquantititive spectrographic analyses of sedimentary rocks are small for a specific rock type; therefore, considerable confidence may be placed upon the average chemical appears to be no significant relation between chemical composition of mudstone or sandstone and distance from known uranium-vanadium ore or mineralization rock. Mudstone generally contains greater concentrations of the elements studied than sandstone. The chemical composition of red mudstone is similar to the chemical composition of green mudstone except that red mudstone was found to contain almost twice as much calcium as green mudstone in the Jo Dandy area. Samples of the unoxidized sandstone from the Jo Dandy area contain about twice as much calcium, three times as much strontium, but only about one-half as much as zirconium as oxidized sandstone; except for these elements the chemical compositions of both categories of sandstone are similar. Samples of sandstone of the Salt Wash member in the Jo Dandy area contain more potassium, magnesium, vanadium, and nickel than “average sandstone” of the Salt Wash member. The distribution of bismuth in rocks of the Jo Dandy area suggests that bismuth and perhaps part of the potassium and magnesium found in rocks of the Salk Wash member were either derived from solutions which ascended from the underlying salt- and gypsum-bearing Paradox member that was incorporated with rocks of the Salt Wash during sedimentation.

Genetics Home Reference: Dandy-Walker malformation

MedlinePlus

... KA, Lehmann OJ, Hudgins L, Chizhikov VV, Bassuk AG, Ades LC, Krantz ID, Dobyns WB, Millen KJ. ... qualified healthcare professional . About Selection Criteria for Links Data Files & API Site Map Subscribe Customer Support USA. ...

Clinical and genetic heterogeneity in patients with mosaic variegated aneuploidy: delineation of clinical subtypes.

PubMed

García-Castillo, Herbert; Vásquez-Velásquez, Ana Isabel; Rivera, Horacio; Barros-Núñez, Patricio

2008-07-01

Mosaic variegated aneuploidy (MVA) is a rare autosomal recessive syndrome related to BUB1B gene mutations and characterized by multiple mosaic aneuploidies, cancer predisposition, and a distinct phenotype. We report on two mildly affected sibs with MVA syndrome but without BUB1B mutation. Both patients exhibited growth retardation, frontal bossing, triangular face and micrognathia but not microcephaly or cancer. Aneuploidies were assessed both in G-banded metaphases from lymphocyte cultures and in interphase nuclei from buccal cells by FISH. Screening of 23 exons and intron-exon boundaries of BUB1B was also carried out. These patients were then compared with other 19 MVA patients screened for BUB1B mutations. Around one half of the cultured lymphocytes from our patients had aneuploidies ranging from nullisomies to heptasomies; the most frequent abnormalities were trisomies (42%) and monosomies (28%). FISH results demonstrated more chromosomal losses than gains. Screening of BUB1B in our two patients failed to identify any mutation. A review of the 21/35 patients screened for BUB1B demonstrated three clinical pictures. Patients with monoallelic BUB1B mutations were severely affected with Dandy-Walker complex (7/8), cataracts (6/6), and Wilms' tumor (7/8); premature chromatid separation (PCS) was observed in 8/8 propositi and 7/7 carrier parents. Patients without BUB1B mutations were mildly affected with no evidence of cancer, Dandy-Walker malformation or cataract, and rarely (1/7) showed PCS. Finally, patients with biallelic BUB1B mutations showed a moderate phenotype. The distinct MVA clinical groups delineated here point to involvement of at least another mitotic spindle checkpoint gene in addition to the BUB1B gene. (c) 2008 Wiley-Liss, Inc.

Intelligently Controllable Walker with Magnetorheological Fluid Brake

NASA Astrophysics Data System (ADS)

Kikuchi, Takehito; Tanida, Sosuke; Tanaka, Toshimasa; Kobayashi, Keigo; Mitobe, Kazuhisa

Caster walkers are supporting frames with casters and wheels. These tools are regularly utilized as life support tools or walking rehabilitation tools in hospitals, nursing homes and individual residences. Users of the walkers can easily move it thanks to its wheels and casters. However falling accidents often happen when it moves without users. The falling accident is very serious problem and one of leading causes of secondary injuries. In the other case, it is hard to move to desired directions if users have imbalance in their motor functions or sensory functions, e.g., hemiplegic patients. To improve safeness and operability of the walkers, we installed compact MR fluid brakes on the wheels and controlled walking speed and direction of the walker. We named this intelligently controllable walker, “i-Walker” and discussed on the control methods and experimental results in this paper. Preliminary trials for direction control of the first-generation of the i-Walker (i-Walker1) are presented. On the basis of the results, we improved the control method and hardware of the i-Walker1, and developed the second-generation (i-Walker2). System description and experimental results of the i-Walker2 are also described. The i-Walker2 has better operability and lower energy consumption than that of the i-Walker1. The line-tracing controller of the i-Walker2 well controls human motions during walking experiments on the target straight line.

Foldable Walker

NASA Technical Reports Server (NTRS)

1979-01-01

Paraplegics, who number about 100,000 in the United States, depend on crutches for their mobility on level ground. But crutches are ineffective on stairways; for climbing or descending, the paraplegic needs a stable pair of rails to push against. Aluminum metal walkers are designed for use on level surfaces, hence they have little utility on stairs; and, although lightweight, they are too heavy to be carried by the paraplegic while walking on crutches. There exists a need for a walker specifically designed for stair use and made of material much lighter than aluminum.

Three friendly walkers

NASA Astrophysics Data System (ADS)

Jensen, Iwan

2017-01-01

More than 15 years ago Guttmann and Vöge (2002 J. Stat. Plan. Inference 101 107), introduced a model of friendly walkers. Since then it has remained unsolved. In this paper we provide the exact solution to a closely allied model which essentially only differs in the boundary conditions. The exact solution is expressed in terms of the reciprocal of the generating function for vicious walkers which is a D-finite function. However, ratios of D-finite functions are inherently not D-finite and in this case we prove that the friendly walkers generating function is the solution to a non-linear differential equation with polynomial coefficients, it is in other words D-algebraic. We find using numerically exact calculations a conjectured expression for the generating function of the original model as a ratio of a D-finite function and the generating function for vicious walkers. We obtain an expression for this D-finite function in terms of a {{}2}{{F}1} hypergeometric function with a rational pullback and its first and second derivatives. Dedicated to Tony Guttmann on the occasion of his 70th birthday.

Baby walkers--health visitors' current practice, attitudes and knowledge.

PubMed

Kendrick, Denise; Illingworth, Rachel; Hapgood, Rhydian; Woods, Amanda J; Collier, Jacqueline

2003-09-01

Baby walkers are a commonly used item of nursery equipment. Between 12% and 50% of parents whose infant uses a walker report that their child has suffered a walker-related injury. Health visitors' knowledge, attitudes and practice with regard to walkers and related health education has not been explored so far. The aim of the study was to describe health visitors' knowledge of walkers and walker-related injuries, their attitudes towards walkers and current practice with regard to walker health education, and to examine the relationship between knowledge and attitudes and knowledge and practice. A survey was carried out with 64 health visitors prior to participation in a randomized controlled trial assessing the effectiveness of an educational package in reducing baby walker use. The response rate was 95%. Half of the health visitors always discussed walkers postnatally, most frequently at the 6-9 month check. Most did not usually discuss the frequency of walker-related injuries. Most had negative attitudes towards walkers, but believed that parents hold positive attitudes to them and that it is hard to persuade parents not to use them. Health visitors had a limited knowledge of walker use and walker-related injuries. Those giving advice on walkers most often had higher knowledge scores than those giving advice less often (P = 0.03). Those with higher knowledge scores held more negative attitudes towards walkers (rs = 0.29, P = 0.023) and believed parents to have more positive attitudes towards walkers (rs = -0.49, P < 0.001). Few health visitors had resources to discuss walkers. Health visitor advice regarding walkers needs to be given earlier in the postnatal period than is currently common practice, and they need more knowledge about walker use and related injuries. Education about baby walkers needs to be incorporated into undergraduate and in-service education, which may need to include the development of skills in exploring reasons why parents use walkers and

Why is walker-assisted gait metabolically expensive?

PubMed

Priebe, Jonathon R; Kram, Rodger

2011-06-01

Walker-assisted gait is reported to be ∼200% more metabolically expensive than normal bipedal walking. However, previous studies compared different walking speeds. Here, we compared the metabolic power consumption and basic stride temporal-spatial parameters for 10 young, healthy adults walking without assistance and using 2-wheeled (2W), 4-wheeled (4W) and 4-footed (4F) walker devices, all at the same speed, 0.30m/s. We also measured the metabolic power demand for walking without any assistive device using a step-to gait at 0.30m/s, walking normally at 1.25m/s, and for repeated lifting of the 4F walker mimicking the lifting pattern used during 4F walker-assisted gait. Similar to previous studies, we found that the cost per distance walked was 217% greater with a 4F walker at 0.30m/s compared to unassisted, bipedal walking at 1.25m/s. Compared at the same speed, 0.30m/s, using a 4F walker was still 82%, 74%, and 55% energetically more expensive than walking unassisted, with a 4W walker and a 2W walker respectively. The sum of the metabolic cost of step-to walking plus the cost of lifting itself was equivalent to the cost of walking with a 4F walker. Thus, we deduce that the high cost of 4F walker assisted gait is due to three factors: the slow walking speed, the step-to gait pattern and the repeated lifting of the walker. Copyright © 2011 Elsevier B.V. All rights reserved.

A walker with a device of partial suspension for patients with gait disturbance: body weight supported walker.

PubMed

Ochi, Mitsuhiro; Makino, Kenichiro; Wada, Futoshi; Saeki, Satoru; Hachisuka, Kenji

2009-09-01

We developed a walker, the Body Weight Supported (BWS) Walker, with a device of partial suspension for patients with gait disturbance. It consists of a light frame with casters, a harness, and a winch system. One therapist alone can perform gait training safely with the BWS Walker without any additional physical load, even if a patient has severe gait disturbance, and the therapist can concentrate on evaluating and improving the patient' s standing balance and gait pattern. Because the BWS Walker is less expensive, simpler, and easier to operate than other BWS systems, we believe the BWS Walker can be widely applicable in training for patients with severe and moderate gait disturbance.

A walking prescription for statically-stable walkers based on walker/terrain interaction

NASA Technical Reports Server (NTRS)

Nagy, Peter V.; Whittaker, William L.; Desa, Subhas

1992-01-01

The walker/terrain interaction phenomena for the control of a statically stable walking machine are described. The algorithms, measures, and knowledge of walker/terrain interaction phenomena are then combined to form a prescription for how to walk on general terrain. This prescription consists of two parts: nominal control and reactive control. The function of nominal control is the evaluation and execution of planned motions, based on predicted foot force redistributions, to achieve reliable locomotion. The function of reactive control is the monitoring of walker/terrain interaction in real-time to detect anomalous conditions and then respond with the appropriate reflexive actions. Simulations and experiments have been used to test and verify various aspects of the walking prescription.

Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment

PubMed Central

Costa, Vania; Tu, Hong Anh; Wells, David; Weir, Mark; Holubowich, Corinne; Walter, Melissa

2017-01-01

Background Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers. Methods We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices. Results We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00–0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01–0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval −0.11–0.14]). The economic analysis showed that total contact casting and irremovable

Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment.

PubMed

2017-01-01

Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers. We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices. We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00-0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01-0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval -0.11-0.14]). The economic analysis showed that total contact casting and irremovable cast walkers were less expensive and

Recent progress on DNA based walkers.

PubMed

Pan, Jing; Li, Feiran; Cha, Tae-Gon; Chen, Haorong; Choi, Jong Hyun

2015-08-01

DNA based synthetic molecular walkers are reminiscent of biological protein motors. They are powered by hybridization with fuel strands, environment induced conformational transitions, and covalent chemistry of oligonucleotides. Recent developments in experimental techniques enable direct observation of individual walkers with high temporal and spatial resolution. The functionalities of state-of-the-art DNA walker systems can thus be analyzed for various applications. Herein we review recent progress on DNA walker principles and characterization methods, and evaluate various aspects of their functions for future applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

Aging in mortal superdiffusive Lévy walkers.

PubMed

Stage, Helena

2017-12-01

A growing body of literature examines the effects of superdiffusive subballistic movement premeasurement (aging or time lag) on observations arising from single-particle tracking. A neglected aspect is the finite lifetime of these Lévy walkers, be they proteins, cells, or larger structures. We examine the effects of aging on the motility of mortal walkers, and discuss the means by which permanent stopping of walkers may be categorized as arising from "natural" death or experimental artifacts such as low photostability or radiation damage. This is done by comparison of the walkers' mean squared displacement (MSD) with the front velocity of propagation of a group of walkers, which is found to be invariant under time lags. For any running time distribution of a mortal random walker, the MSD is tempered by the stopping rate θ. This provides a physical interpretation for truncated heavy-tailed diffusion processes and serves as a tool by which to better classify the underlying running time distributions of random walkers. Tempering of aged MSDs raises the issue of misinterpreting superdiffusive motion which appears Brownian or subdiffusive over certain time scales.

Aging in mortal superdiffusive Lévy walkers

NASA Astrophysics Data System (ADS)

Stage, Helena

2017-12-01

A growing body of literature examines the effects of superdiffusive subballistic movement premeasurement (aging or time lag) on observations arising from single-particle tracking. A neglected aspect is the finite lifetime of these Lévy walkers, be they proteins, cells, or larger structures. We examine the effects of aging on the motility of mortal walkers, and discuss the means by which permanent stopping of walkers may be categorized as arising from "natural" death or experimental artifacts such as low photostability or radiation damage. This is done by comparison of the walkers' mean squared displacement (MSD) with the front velocity of propagation of a group of walkers, which is found to be invariant under time lags. For any running time distribution of a mortal random walker, the MSD is tempered by the stopping rate θ . This provides a physical interpretation for truncated heavy-tailed diffusion processes and serves as a tool by which to better classify the underlying running time distributions of random walkers. Tempering of aged MSDs raises the issue of misinterpreting superdiffusive motion which appears Brownian or subdiffusive over certain time scales.

Two females with mutations in USP9X highlight the variable expressivity of the intellectual disability syndrome.

PubMed

Au, P Y B; Huang, L; Broley, S; Gallagher, L; Creede, E; Lahey, D; Ordorica, S; Mina, K; Boycott, K M; Baynam, G; Dyment, D A

2017-07-01

The genetic causes of intellectual disability (ID) are heterogeneous and include both chromosomal and monogenic etiologies. The X-chromosome is known to contain many ID-related genes and males show a marked predominance for intellectual disability. Here we report two females with syndromic intellectual disability. The first individual was relatively mild in her presentation with mild-moderate intellectual disability, hydronephrosis and altered pigmentation along the lines of Blaschko without additional congenital anomalies. A second female presented shortly after birth with dysmorphic facial features, post-axial polydactyly and, on follow-up assessment, demonstrated moderate intellectual disability. Chromosomal studies for Individual 1 identified an X-chromosome deletion due to a de novo pericentric inversion; the inversion breakpoint was associated with deletion of the 5'UTR of the USP9X, a gene which has been implicated in a syndromic intellectual disability affecting females. The second individual had a de novo frameshift mutation detected by whole-exome sequencing that was predicted to be deleterious, NM_001039590.2 (USP9X): c.4104_4105del (p.(Arg1368Serfs*2)). Haploinsufficiency of USP9X in females has been associated with ID and congenital malformations that include heart defects, scoliosis, dental abnormalities, anal atresia, polydactyly, Dandy Walker malformation and hypoplastic corpus callosum. The extent of the congenital malformations observed in Individual 1 was less striking than Individual 2 and other individuals previously reported in the literature, and suggests that USP9X mutations in females can have a wider spectrum of presentation than previously appreciated. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Fall prevention walker during rehabilitation

NASA Astrophysics Data System (ADS)

Tee, Kian Sek; E, Chun Zhi; Saim, Hashim; Zakaria, Wan Nurshazwani Wan; Khialdin, Safinaz Binti Mohd; Isa, Hazlita; Awad, M. I.; Soon, Chin Fhong

2017-09-01

This paper proposes on the design of a walker for the prevention of falling among elderlies or patients during rehabilitation whenever they use a walker to assist them. Fall happens due to impaired balance or gait problem. The assistive device is designed by applying stability concept and an accelerometric fall detection system is included. The accelerometric fall detection system acts as an alerting device that acquires body accelerometric data and detect fall. Recorded accelerometric data could be useful for further assessment. Structural strength of the walker was verified via iterations of simulation using finite element analysis, before being fabricated. Experiments were conducted to identify the fall patterns using accelerometric data. The design process and detection of fall pattern demonstrates the design of a walker that could support the user without fail and alerts the helper, thus salvaging the users from injuries due to fall and unattended situation.

Neutral signature Walker-CSI metrics

NASA Astrophysics Data System (ADS)

Coley, A.; Musoke, N.

2015-03-01

We will construct explicit examples of four-dimensional neutral signature Einstein Walker spaces for which all of the polynomial scalar curvature invariants are constant. We show that these Einstein Walker spaces are Kundt. We then investigate the mathematical properties of the spaces, including holonomy and universality.

Quincke random walkers

NASA Astrophysics Data System (ADS)

Pradillo, Gerardo; Heintz, Aneesh; Vlahovska, Petia

2017-11-01

The spontaneous rotation of a sphere in an applied uniform DC electric field (Quincke effect) has been utilized to engineer self-propelled particles: if the sphere is initially resting on a surface, it rolls. The Quincke rollers have been widely used as a model system to study collective behavior in ``active'' suspensions. If the applied field is DC, an isolated Quincke roller follows a straight line trajectory. In this talk, we discuss the design of a Quincke roller that executes a random-walk-like behavior. We utilize AC field - upon reversal of the field direction a fluctuation in the axis of rotation (which is degenerate in the plane perpendicular to the field and parallel to the surface) introduces randomness in the direction of motion. The MSD of an isolated Quincke walker depends on frequency, amplitude, and waveform of the electric field. Experiment and theory are compared. We also investigate the collective behavior of Quincke walkers,the transport of inert particles in a bath of Quincke walkers, and the spontaneous motion of a drop containing Quincke active particle. supported by NSF Grant CBET 1437545.

Effects of modified short-leg walkers on ground reaction force characteristics.

PubMed

Keefer, Maria; King, Jon; Powell, Douglas; Krusenklaus, John H; Zhang, Songning

2008-11-01

Although short-leg walkers are often used in the treatment of lower extremity injuries (ankle and foot fractures and severe ankle sprains), little is known about the effect the short-leg walker on gait characteristics. The purpose was to examine how heel height modifications in different short-leg walkers and shoe side may affect ground reaction forces in walking. Force platforms were used to collect ground reaction force data on 10 healthy participants. Five trials were performed in each of six conditions: lab shoes, gait walker, gait walker with heel insert on shoe side, gait walker modified with insert on walker side, equalizer walker, and equalizer walker with heel insert on shoe side. Conditions were randomized and walking speed was standardized between conditions. A 2x6 (sidexcondition) repeated analysis of variance was used on selected ground reaction force variables (P<0.05). The application of a walker created peak vertical and anteroposterior ground reaction forces prior to the normal peaks associated with the loading response. Wearing a walker introduced an elevated minimum vertical ground reaction force in all conditions except the equalizer walker when compared to shoe on the shoe side. Peak propulsive anteroposterior ground reaction forces were smaller in all walker conditions compared to shoe on walker side. The application of heel insert in gait walker with heel insert (on shoe side) and gait walker modified (on walker side) does not diminish the minimum vertical ground reaction force as hypothesized. Wearing a walker decreases the peak propulsive anteroposterior ground reaction force on the walker side and induces asymmetrical loading.

AP1S2 is mutated in X-linked Dandy–Walker malformation with intellectual disability, basal ganglia disease and seizures (Pettigrew syndrome)

PubMed Central

Cacciagli, Pierre; Desvignes, Jean-Pierre; Girard, Nadine; Delepine, Marc; Zelenika, Diana; Lathrop, Mark; Lévy, Nicolas; Ledbetter, David H; Dobyns, William B; Villard, Laurent

2014-01-01

MRXS5 or Pettigrew syndrome was described 20 years ago in a four generation family including nine affected individuals presenting with facial dysmorphism, intellectual disability, Dandy–Walker malformation and inconstant choreoathetosis. Four individuals had iron deposition in the basal ganglia seen on MRI or at autopsy. The mutation causing Pettigrew has remained elusive since the initial description of the condition. We report the identification of a mutation in the X-linked AP1S2 gene in the original Pettigrew syndrome family using X-chromosome exome sequencing. We report additional phenotype details for several of the affected individuals, allowing us to further refine the phenotype corresponding to this X-linked intellectual disability syndrome. The AP1S2 c.426+1 G>T mutation segregates with the disease in the Pettigrew syndrome family and results in loss of 46 amino acids in the clathrin adaptor complex small chain domain that spans most of the AP1S2 protein sequence. The mutation reported here in AP1S2 is the first mutation that is not predicted to cause a premature termination of the coding sequence or absence of the AP1S2 protein. Although most of the families affected by a mutation in AP1S2 were initially described as having different disorders assigned to at least three different OMIM numbers (MIM 300629, 300630 and 304340), our analysis of the phenotype shows that they are all the same syndrome with recognition complicated by highly variable expressivity that is seen within as well as between families and is probably not explained by differences in mutation severity. PMID:23756445

The use of baby walkers in Iranian infants.

PubMed

Shiva, F; Ghotbi, F; Yavari, S F

2010-08-01

A study was conducted to define the pattern of baby walker usage and the rate of walker-related injuries in infants, as well as to determine the effects of baby walkers on the start of independent walking among infants. Families of infants aged six months to two years who presented at health facility clinics in 2007 and 2008 were enrolled in the study. The study team interviewed the primary caregiver and documented the relevant data on a pre-designed questionnaire. The data of users of baby walkers was compared with that of non-users. Walkers were used by 54.5 percent of 414 infants. Their use was significantly higher in one-child families (p-value is 0.009) and in those with higher parental education levels (p-value is less than 0.001). 78.6 percent of users and 85 percent of non-users were walking by 12 months of age (p-value is 0.283); no significant difference was observed between the two groups in terms of the age at which the infants starting walking (p-value is 0.401). 76.8 percent of parents of users versus 8.2 percent of parents of non-users believed that walkers promote early walking (p-value is less than 0.001). 44.7 percent of parents of users knew that walkers can be hazardous, as compared to 22.3 percent of parents of non-users. No serious injury was reported, but 14.1 percent of infants sustained trivial walker-associated injuries. Baby walkers do not hasten independent walking and may be associated with injuries. However, it was noted that knowledge of the associated hazards has not deterred parents from using baby walkers for their infants.

The chaotic interaction of two walkers

NASA Astrophysics Data System (ADS)

Tadrist, Loic; Samara, Naresh; Schlagheck, Peter; Gilet, Tristan

2016-11-01

A droplet bouncing on a vertically vibrated bath may be propelled horizontally by the Faraday waves that it generates at each rebound. This association of a wave and a particle is called a walker. Ten years ago, Yves Couder and co-workers noted that the dynamical encounter of two walkers may lead to either scattered trajectories or orbital motion. In this work, we investigate the interaction of two walkers more systematically. The walkers are launched towards each other with finely controlled initial conditions. Output trajectories are classified in four types: scattering, orbiting, wandering and complex. The interaction appears stochastic: the same set of initial parameters (to the measurement accuracy) can produce different outputs. Our analysis of the underlying chaos provides new insights on the stochastic nature of this experiment. This work is supported by the ARC Quandrops of the Wallonia-Brussels Federation.

Bathymetry of Walker Lake, West-Central Nevada

USGS Publications Warehouse

Lopes, Thomas J.; Smith, J. LaRue

2007-01-01

Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near

A review of the functionalities of smart walkers.

PubMed

Martins, Maria; Santos, Cristina; Frizera, Anselmo; Ceres, Ramón

2015-10-01

There is a need to conceptualize and improve the investigation and developments in assistive devices, focusing on the design and effectiveness of walkers in the user's rehabilitation process and functional compensation. This review surveys the importance of smart walkers in maintaining mobility and discusses their potential in rehabilitation and their demands as assistive devices. It also presents related research in addressing and quantifying the smart walker's efficiency and influence on gait. Besides, it discusses smart walkers focusing on studies related to the concept of autonomous and shared-control and manual guidance, the use of smart walkers as personal helpers to sit-to-stand and diagnostic tools for patients' rehabilitation through the evaluation of their gait. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Do orthotic walkers affect knee and hip function during gait?

PubMed

Richards, Jim; Payne, Katherine; Myatt, Darren; Chohan, Ambreen

2016-02-01

Much previous research on orthotic walkers has focussed on their ability to offload structures in the foot and ankle; however, little is known about their effects on lower limb mechanics. This study aimed to determine effects of two orthotic walkers on the biomechanics of the knee and hip joints compared to standardised footwear. A total of 10 healthy participants walked under three conditions: Walker A (Össur, Iceland), Walker B (DJO Global, USA) and standardised footwear (Hotter, UK). Kinematic and kinetic data were collected using a Qualisys motion analysis system (Qualisys Medical AB, Sweden) and force plates (AMTI, Boston, MA, USA). Significant differences were seen in hip kinematics and knee moments between walkers and standardised footwear and in knee kinematics between Walker A and standardised footwear. Both walkers show significant kinematic and kinetic differences compared with standardised footwear; however, Walker A appeared to produce greater deviation, including potentially damaging greater hyperextension moments at the knee. Further research is needed into the effects of orthotic walkers on knee and hip joint mechanics, which should help to inform future designs of walker, with greater focus on obtaining a more normal gait pattern. © The International Society for Prosthetics and Orthotics 2014.

Pediatricians' attitude about the use of infant walkers.

PubMed

Kara, Semra; Yilmaz, Ayşe Esra; Gümüş Dogan, Derya; Bilici, Meki; Turkay, Sadi; Akca, Halise; Catal, Ferhat

2013-12-01

Infant walkers are still very popular even though their use might cause injuries. A survey was carried out to obtain information about attitudes and pediatricians' approach regarding the use of infant walkers. Two hundred and forty seven pediatricians who attended the 44th Turkish Congress of Pediatrics and Europediatrics (2008) were invited to reply to a questionnaire prepared by the authors. Two hundred and twenty six questionnaires replied in full were included. The median age of participants (119 women) was 39 years old (range: 29-58 years old). Out of the total, 4% recommended the use of a walker; 32.2% left the decision to parents' judgment, and 63.7% did not recommend its use. A hundred and five had previously treated an infant who had an injury associated to the use of the walker; out of them, 73.3% did not recommend its use and 57.1% stated that there should be a ban on the sale and manufacture of walkers. Out of the total number of surveyed pediatricians, 4% recommend the use of infant walkers and over 30% leave this decision to parents. Those pediatricians who took care of babies who had an injury associated to the use of a walker were less prone to recommending it.

Using walker during walking: a pilot study for health elder.

PubMed

Po-Chan, Yeh; Cherng-Yee, Leung

2012-01-01

Walker operation completely relies on the walker handle, however most marketed walkers possess two horizontal handles. Several researchers have suggested that horizontal handles might lead to wrist injury. Therefore, the purpose of this study is to assess the relevant design aspects of walker for elderly people. 28 elders participated in this study; when the experiment was started, subject walked on the tile for 3 meter distance twice by using walker. Data for analysis were selected at the corresponding wrist deviation and vertical force. The results showed that during walker using, the mean wrist deviation was greater than zero. The largest vertical force is significantly larger than the smallest one, and different wrist deviation occurred at three phases, the largest wrist deviation while raising walker is larger than the smallest one, however, no significant different was found between the largest and smallest wrist deviation while pressing walker. No significant correlation occurred between weight and wrist deviation. The correlation between weight and vertical force was significantly positive. With wrist deviation walker use may cause injury to upper-limb, however wrists remain in a neutral position during hand movement to prevent damage. The findings of this study should improve the design of walker handles to reduce the wrist deviations of users.

21 CFR 890.3825 - Mechanical walker.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Mechanical walker. 890.3825 Section 890.3825 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a...

21 CFR 890.3825 - Mechanical walker.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Mechanical walker. 890.3825 Section 890.3825 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a...

21 CFR 890.3825 - Mechanical walker.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Mechanical walker. 890.3825 Section 890.3825 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a...

21 CFR 890.3825 - Mechanical walker.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Mechanical walker. 890.3825 Section 890.3825 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a...

21 CFR 890.3825 - Mechanical walker.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mechanical walker. 890.3825 Section 890.3825 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a...

Wheeled and standard walkers in Parkinson's disease patients with gait freezing.

PubMed

Cubo, Esther; Moore, Charity G; Leurgans, Sue; Goetz, Christopher G

2003-10-01

Compare the efficacy of two walking assistance devices (wheeled walker and standard walker) to unassisted walking for patients with PD and gait freezing. Although numerous walking devices are used clinically, their relative effects on freezing and walking speed have never been systematically tested. Nineteen PD patients (14 non-demented) walked under three conditions in randomized order: unassisted walking, standard walker, and wheeled walker. Patients walked up to three times in each condition through a standard course that included rising from a chair, walking through a doorway, straightway walking, pivoting, and return. Total walking time, freezing time and number of freezes were compared for the three conditions using mixed models (walking time) and Friedman's test (freezing). The wheeled walker was further studied by comparing the effect of an attached laser that projected a bar of light on the floor as a visual walking cue. Use of either type of device significantly slowed walking compared to unassisted walking. Neither walker reduced any index of freezing, nor the laser attachment offered any advantage to the wheeled walker. The standard walker increased freezing, and the wheeled walker had no effect on freezing. Among the non-demented subjects (n=14), the same patterns occurred, although the walking speed was less impaired by the wheeled walker than the standard walker in this group. Though walkers may stabilize patients and increase confidence, PD patients walk more slowly when using them, without reducing freezing. Because the wheeled walker was intermediate for walking time and does not aggravate freezing, if walkers are used for these subjects, this type of walker should be favored.

STS-30 Commander Walker on forward flight deck

NASA Technical Reports Server (NTRS)

1989-01-01

On Atlantis', Orbiter Vehicle (OV) 104's, forward flight deck between commanders and pilots seats, STS-30 Commander David M. Walker smiles while having his picture taken. Walker, wearing a mission polo shirt and light blue flight coverall pants, holds onto the commanders seat back. Forward flight control panels are visible above Walker's head and behind him.

Walker circulation in a transient climate

NASA Astrophysics Data System (ADS)

Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

2016-04-01

The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

Biomimetic Molecular Signaling using DNA Walkers on Microparticles.

PubMed

Damase, Tulsi Ram; Spencer, Adam; Samuel, Bamidele; Allen, Peter B

2017-06-22

We report the release of catalytic DNA walkers from hydrogel microparticles and the detection of those walkers by substrate-coated microparticles. This might be considered a synthetic biology analog of molecular signal release and reception. One type of particles was coated with components of a DNA one-step strand displacement (OSD) reaction to release the walker. A second type of particle was coated with substrate (or "track") for the molecular walker. We distinguish these particle types using fluorescence barcoding: we synthesized and distinguished multiple particle types with multicolor fluorescence microscopy and automated image analysis software. This represents a step toward amplified, multiplex, and microscopically localized detection based on DNA nanotechnology.

75 FR 51178 - Safety Standard for Infant Walkers; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... provision concerning warning statements on walkers with parking brakes. DATES: Effective on December 21... the last sentence. Another provision, at Sec. 1216.2(b)(21)(i), concerning a warning statement for walkers with parking brakes omitted a phrase indicating that the warning is only required for walkers that...

Classification of walking ability of household walkers versus community walkers based on K-BBS, gait velocity and upright motor control.

PubMed

Joa, K L; Kwon, S Y; Choi, J W; Hong, S E; Kim, C H; Jung, H Y

2015-10-01

Few guidelines are available to assist clinicians with assessment of whether a patient is a household or community walker. To assess the Korean Berg balance scale (K-BBS) and gait velocity cut-off points of a household walker versus a community walker and evaluate which combinations of the three scales (K-BBS, upright motor control test (UMCT), and gait velocity) best assessed walking ability. Cross-sectional study. Outpatient. A total of 124 stroke patients with walking difficulty. Participants were classified into one of six walking classifications (three household walkers and three community walkers) and K-BBS, UMCT, and gait velocity were evaluated. The optimal cut-off scores for walking classification were determined based on received operator characteristic (ROC) analyses. The cut-off value of K-BBS for dividing the household walker versus the community walker was 42 points. The cut-off value of gait velocity was 48 m/s for the community walker. The area under the ROC curve of the combined K-BBS and gait velocity values was larger than that of each individual scale and those of the other combined scales. The results suggest that K-BBS, gait velocity, and UMCT are useful instruments for classifying household ambulation and community ambulation. The authors recommend K-BBS as single scale and K-BBS and gait velocity as combined scales for evaluating community ambulation in stroke patients In this report, we have some clinical implication. We recommend 3 outcome measures to assess walking ability about home or community; K-BBS (>42 points), gait speed (>48 m/min), UMCT (strong grade in either knee flexion of extension). Suggesting cut-off points of Korean Berg balance scale, gait velocity, and level of upright motor control test for community ambulation could be used as outcome measures to evaluate patient's actual performance level. It is also important to combine several scales for determining walking classification. We suggest to evaluate walking ability by

The role of walkers' needs and expectations in supporting maintenance of attendance at walking groups: a longitudinal multi-perspective study of walkers and walk group leaders.

PubMed

Kassavou, Aikaterini; Turner, Andrew; French, David P

2015-01-01

There is good evidence that when people's needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers' needs and walk leaders' actions to address them. The present study was aimed at addressing both of these gaps in the research. Two preliminary thematic analyses were conducted on face-to-face interviews with (a) eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b) eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders. Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers' personalities. Walk leaders reported a lack of efficacy to effectively address walkers' needs. Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers' maintenance at walking groups. This should result in greater retention of walkers in walking groups, thereby

Intelligent control of a smart walker and its performance evaluation.

PubMed

Grondin, Simon L; Li, Qingguo

2013-06-01

Recent technological advances have allowed the development of force-dependent, intelligently controlled smart walkers that are able to provide users with enhanced mobility, support and gait assistance. The purpose of this study was to develop an intelligent rule-based controller for a smart walker to achieve a smooth interaction between the user and the walker. This study developed a rule-based mapping between the interaction force, measured by a load cell attached to the walker handle, and the acceleration of the walker. Ten young, healthy subjects were used to evaluate the performance of the proposed controller compared to a well-known admittance-based control system. There were no significant differences between the two control systems concerning their user experience, velocity profiles or average cost of transportation. However, the admittance-based control system required a 1.2N lower average interaction force to maintain the 1m/s target speed (p = 0.002). Metabolic data also indicated that smart walker-assisted gait could considerably reduce the metabolic demand of walking with a four-legged walker.

AmeriFlux US-WBW Walker Branch Watershed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyers, Tilden

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-WBW Walker Branch Watershed. Site Description - The stand is over 50 years old, having regenerated from agricultural land.This site is located near Oak Ridge, Tennessee near the Walker Branch Watershed.

Exploration and Trapping of Mortal Random Walkers

NASA Astrophysics Data System (ADS)

Yuste, S. B.; Abad, E.; Lindenberg, Katja

2013-05-01

Exploration and trapping properties of random walkers that may evanesce at any time as they walk have seen very little treatment in the literature, and yet a finite lifetime is a frequent occurrence, and its effects on a number of random walk properties may be profound. For instance, whereas the average number of distinct sites visited by an immortal walker grows with time without bound, that of a mortal walker may, depending on dimensionality and rate of evanescence, remain finite or keep growing with the passage of time. This number can in turn be used to calculate other classic quantities such as the survival probability of a target surrounded by diffusing traps. If the traps are immortal, the survival probability will vanish with increasing time. However, if the traps are evanescent, the target may be spared a certain death. We analytically calculate a number of basic and broadly used quantities for evanescent random walkers.

Modern lacustrine stromatolites, Walker Lake, Nevada

NASA Astrophysics Data System (ADS)

Osborne, Robert H.; Licari, Gerald R.; Link, Martin H.

1982-05-01

The Walker River drainage basin occupies about 10,000 km 2 in western Nevada and parts of California and is essentially a closed hydrologic system which drains from the crest of the Sierra Nevada in California and terminates in Walker Lake, Nevada. Walker Lake trends north and is about 27.4 km long and 8 km wide with water depths exceeding 30.5 m. The lake is situated in an asymmetric basin with steep alluvial fans flanking the western shoreline (Wassuk Range) and more gentle but areally more extensive alluvial fans flanking the eastern shoreline (Gillis Range). Exposed lake terraces and the present shoreline of Walker Lake record a sequence of Pleistocene and Holocene stromatolitic and tufaceous carbonate deposits. Small generalized and columnar stromatolites, frequently encrusted on exposed coarse-grained clasts or bedrock, are present along parts of the nearshore margin of Walker Lake and at elevated lake stands. Columnar stromatolites as much as 4 cm high are subcylindrical to club shaped discrete, and laterally linked at the base with local branching. These digitate stromatolites start as wavy, generalized stromatolites which are vertically transitional to small, laterally linked cabbage heads with laminae which thicken over the crests. Although algal structures are not well preserved in the older stromatolites, recent precipitation of low magnesium calcite occurs as smooth encrustations and as tiny mounds which are consistently associated with a diverse, seasonally variable, green and blue-green algal community including Cladophora glomerata, Ulothrix (cf. aequalis), Gongrosira, Schizothrix, Amphithrix janthina, Calothrix, Homeothrix, Spirulina, Anabaena, Lyngbya, and Entophysalis. Cladophora glomerata and a species of Ulothrix, which are the two most abundant algae within the Walker Lake stromatolite community, are known to condition semi-alkaline lake water by the removal of CO 2 from bicarbonate during photosynthesis. Such conditioning results in the

Hydrogel Walkers with Electro-Driven Motility for Cargo Transport.

PubMed

Yang, Chao; Wang, Wei; Yao, Chen; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

2015-08-28

In this study, soft hydrogel walkers with electro-driven motility for cargo transport have been developed via a facile mould-assisted strategy. The hydrogel walkers consisting of polyanionic poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylamide) exhibit an arc looper-like shape with two "legs" for walking. The hydrogel walkers can reversibly bend and stretch via repeated "on/off" electro-triggers in electrolyte solution. Based on such bending/stretching behaviors, the hydrogel walkers can move their two "legs" to achieve one-directional walking motion on a rough surface via repeated "on/off" electro-triggering cycles. Moreover, the hydrogel walkers loaded with very heavy cargo also exhibit excellent walking motion for cargo transport. Such hydrogel systems create new opportunities for developing electro-controlled soft systems with simple design/fabrication strategies in the soft robotic field for remote manipulation and transportation.

A new species of Ormocerus Walker (Hymenoptera: Pteromalidae) from North America and a range expansion for Ormocerus latus Walker

USDA-ARS?s Scientific Manuscript database

Ormocerus dirigoius, n. sp. is described and compared to the North American O. americanus Dzhanokmen and Grissell and European species O. latus Walker and O. vernalis Walker. A range expansion into the Nearctic is reported for O. latus, previously only known from the Palearctic. Specimens were colle...

Joseph (Joe) A. Walker

NASA Technical Reports Server (NTRS)

1956-01-01

In March 1945 Joseph A. Walker joined the National Advisory Committee for Aeronautics' Aircraft Engine Research Laboratory, Cleveland, Ohio, (later NASA's Lewis Research Center, now the Glenn Research Center) as a physicist. He transferred to the NACA High-Speed Flight Research Station, Edwards, California in 1951, as a research pilot. For the next fifteen years Walker served as a pilot at the Edwards flight research facility (today known as NASA's Dryden Flight Research Center) on such projects as the Bell X-1#2 (2 flights, first on August 27, 1951), Bell X-1A (1 flight on July 20, 1955), X-1E (21 flights, first on December 12, 1955), Douglas D-558-I #3 Skystreak (14 flights, first on June 29, 1951), Douglas D-558-II #2 Skyrocket (3 flights, first on April 29, 1955), Douglas D-558-II #3 Skyrocket (2 flights, first on May 7, 1954). On the Douglas X-3, Joe was project pilot and made all 20 flights, the first on August 1, 1954. Joe considered this aircraft the 'worst' plane he ever flew. He flew the Northrup X-4 (2 flights, first on October 18, 1951), Bell X-5 (78 flights, first on January 9, 1952). He also flew programs involving the F-100, F-101, F-102, F-104 and the B-47. Walker made the first NASA flight on the North American X-15 on March 25, 1960. His 25th and final X-15 flight on August 22, 1963, reached 354,200 feet, an unofficial record altitude of almost 67 miles. On October 30, 1964, Walker took the first Bell Lunar Landing Research Vehicle (LLRV) on its maiden flight, reaching a peak altitude of 10 feet and a free flight time of just under one minute. Two LLRV's and three Lunar Landing Training Vehicles developed from them were used to develop piloting and operational techniques for lunar landings. In November, he left the program after 35 flights on the first LLRV. Walker flew chase flights as well as research flights. On June 8, 1966 he was flying chase in NASA's F-104N for the Air Force's experimental bomber, North American XB-70A, when he was fatally

Brain magnetic resonance imaging findings in Smith-Lemli-Opitz syndrome.

PubMed

Lee, Ryan W Y; Conley, Sandra K; Gropman, Andrea; Porter, Forbes D; Baker, Eva H

2013-10-01

Smith-Lemli-Opitz syndrome (SLOS) is a neurodevelopmental disorder caused by inborn errors of cholesterol metabolism resulting from mutations in 7-dehydrocholesterol reductase (DHCR7). There are only a few studies describing the brain imaging findings in SLOS. This study examines the prevalence of magnetic resonance imaging (MRI) abnormalities in the largest cohort of patients with SLOS to date. Fifty-five individuals with SLOS (27 M, 28 F) between age 0.17 years and 25.4 years (mean = 6.2, SD = 5.8) received a total of 173 brain MRI scans (mean = 3.1 per subject) on a 1.5T GE scanner between September 1998 and December 2003, or on a 3T Philips scanner between October 2010 and September 2012; all exams were performed at the Clinical Center of the National Institutes of Health. We performed a retrospective review of these imaging studies for both major and minor brain anomalies. Aberrant MRI findings were observed in 53 of 55 (96%) SLOS patients, with abnormalities of the septum pellucidum the most frequent (42/55, 76%) finding. Abnormalities of the corpus callosum were found in 38 of 55 (69%) patients. Other findings included cerebral atrophy, cerebellar atrophy, colpocephaly, white matter lesions, arachnoid cysts, Dandy-Walker variant, and type I Chiari malformation. Significant correlations were observed when comparing MRI findings with sterol levels and somatic malformations. Individuals with SLOS commonly have anomalies involving the midline and para-midline structures of the brain. Further studies are required to examine the relationship between structural brain abnormalities and neurodevelopmental disability in SLOS. © 2013 The Authors. American Journal of Medical Genetics Part A Published by U.S. Government Work.

78 FR 48301 - Establishment of Class E Airspace; Walker, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-08

...-0266; Airspace Docket No. 13-AGL-11] Establishment of Class E Airspace; Walker, MN AGENCY: Federal... at Walker, MN. Controlled airspace is necessary to accommodate new Area Navigation (RNAV) Standard Instrument Approach Procedures at Walker Municipal Airport. The FAA is taking this action to enhance the...

Compliant Walker

NASA Technical Reports Server (NTRS)

Kerley, James J.; Eklund, Wayne; Crane, Alan

1992-01-01

Walker supports person with limited use of legs and back. Enables person to stand upright, move with minimum load, and rest at will taking weight off legs. Consists of wheeled frame with body harness connected compliantly to side structures. Harness supports wearer upright when wearer relaxes and takes weight off lower extremities. Assumes partial to full body weight at user's discretion.

Effective dynamics of a random walker on a heterogeneous ring: Exact results

NASA Astrophysics Data System (ADS)

Masharian, S. R.

2018-07-01

In this paper, by considering a biased random walker hopping on a one-dimensional lattice with a ring geometry, we investigate the fluctuations of the speed of the random walker. We assume that the lattice is heterogeneous i.e. the hopping rate of the random walker between the first and the last lattice sites is different from the hopping rate of the random walker between the other links of the lattice. Assuming that the average speed of the random walker in the steady-state is v∗, we have been able to find the unconditional effective dynamics of the random walker where the absolute value of the average speed of the random walker is -v∗. Using a perturbative method in the large system-size limit, we have also been able to show that the effective hopping rates of the random walker near the defective link are highly site-dependent.

A walker used as a lifting device.

PubMed

Glimskär, Bo; Hjalmarson, Jenny; Lundberg, Stefan; Larsson, Tore

2014-05-01

To develop assistive technology that would help an older person to arise from a kneeling position to a standing one. Developing a prototype, based on an inclusive design and then testing the prototype to verify the approach. The prototype was subsequently tested by a panel of 20 elderly users. These tests were observed and filmed. Participants' experiences of being lifted with the elevation seat were registered with the VIDAR ergonomic assessment system. None of the 20 participants used a walker at that time. In response to a question of whether, assuming they might have to use a walker in the future, they thought that a walker with an elevating seat would be helpful, 18 said that it would. Two of the participants did not believe that they would ever have to use a walker. A simple assistive technology such as a walker equipped with an elevating seat would in many of these cases simplify matters and reduce the distress of people who fall often. In addition, such a device can allow people who fall often to live in their homes longer. For caregivers dealing frequently with people who fall, this assistive device can contribute to decreasing occupational injuries. Development of a lifting device that can help people raise themselves up entirely on their own, or with minimal assistance, would be a revolutionary step for the individual. Lifting devices in use today requires much more extensive assistance from home helpers or others and due to the risk of injuries it is a great value for the helpers that easy to use devices develops. A walker equipped with an elevating seat could even provide a potential for people to stay in their homes longer.

Impact of strut height on offloading capacity of removable cast walkers.

PubMed

Crews, Ryan T; Sayeed, Fraaz; Najafi, Bijan

2012-08-01

Reducing weight-bearing stress to diabetic foot ulcers is critical to healing and commonly called offloading. Removable cast walkers are frequently used for offloading; however, patient compliance is often poor. Walkers commonly extend to the knee. Patients complain about walkers' weight and diminished balance with their use. This study compared the offloading capacity of walkers that varied by height. Heights included: knee, ankle, and shoe levels. To ensure a fair comparison the outsole and insole were standardized across the devices. Eleven diabetic subjects with moderate to high risk of ulceration were recruited. Subjects completed four 20 m walking trials. Subjects performed one trial with each walker and one trial with an athletic shoe. Primary outcomes focused on plantar loading and were measured by pressure insoles. Secondary outcomes were associated with gait kinematics as collected by body worn sensors. Significant differences were found for the peak pressure and pressure time integrals of the different footwear. All walkers performed better than the athletic shoe. The ankle and knee-high devices performed best. Center of mass rotation data showed a trend of the ankle walker yielding a smaller range of motion (18% medial/lateral and 22% anterior/posterior) than the knee level. The ankle-high walker was able to provide similar offloading capacities as the knee-high walker. The diminished weight, along with potentially improved stability, may result in improved compliance with ankle-high walkers. A study comparing the use of the two devices for treating ulcers is now suggested. Copyright © 2012 Elsevier Ltd. All rights reserved.

Do baby walkers delay onset of walking in young children?

PubMed

Burrows, Patricia; Griffiths, Peter

2002-11-01

Baby walkers have been a source of considerable controversy. Some people suggest developmental benefit from their use while others focus on the potential harm that stems from accidents and even suggest developmental delay. This mini-review aimed to determine if use of a baby walker delays affects the onset of walking. The Cochrane library, Embase, CINAHL and Medline were searched for randomized controlled trials (RCTs) and cohort studies, which compared the onset of walking in infants who used baby walkers with a group who did not. Two RCTs and two cohort studies were identified and available for consideration. All of the studies examined the effect of infant walkers on the onset of walking. The results of the two RCTs did not demonstrate a significant effect on the onset of walking. The cohort studies suggest that the use of infant walkers delayed the onset of walking in young children and a pooled analysis of the four studies suggested a delay of between 11 and 26 days. Although the quality of the studies was relatively poor these studies lend no support to the argument that walkers aid the development of walking. The significance of a delay of this magnitude is however unclear. Further work is required to determine whether walkers are an independent causal factor in accidents.

Visible/near-infrared subdiffraction imaging reveals the stochastic nature of DNA walkers.

PubMed

Pan, Jing; Cha, Tae-Gon; Li, Feiran; Chen, Haorong; Bragg, Nina A; Choi, Jong Hyun

2017-01-01

DNA walkers are designed with the structural specificity and functional diversity of oligonucleotides to actively convert chemical energy into mechanical translocation. Compared to natural protein motors, DNA walkers' small translocation distance (mostly <100 nm) and slow reaction rate (<0.1 nm s -1 ) make single-molecule characterization of their kinetics elusive. An important indication of single-walker kinetics is the rate-limiting reactions that a particular walker design bears. We introduce an integrated super-resolved fluorescence microscopy approach that is capable of long-term imaging to investigate the stochastic behavior of DNA walkers. Subdiffraction tracking and imaging in the visible and second near-infrared spectra resolve walker structure and reaction rates. The distributions of walker kinetics are analyzed using a stochastic model to reveal reaction randomness and the rate-limiting biochemical reaction steps.

Antioxidant effects of açaí seed ( Euterpe oleracea ) in anorexia-cachexia syndrome induced by Walker-256 tumor.

PubMed

Nascimento, Vitor Hugo Nunes do; Lima, Carla Dos Santos; Paixão, Jorge Tadeu Campos; Freitas, Jofre Jacob da Silva; Kietzer, Katia Simone

2016-09-01

To assess antioxidant effects of açaí seed extract on anorexia-cachexia induced by Walker-256 tumor. A population of 20 lab rats were distributed into four groups (n=5): Control Group (CG), which only received tumor inoculation. Experimental Group-100 (EG-100), with animals submitted to tumor inoculation and treated with seed extract in a 100 mg / ml concentration through gavage. Experimental Group-200 (EG-200), with animals submitted to tumor inoculation and treated with seed extract in a 200 mg / ml concentration. Placebo Group (GP), which received tumor inoculation and ethanol-water solution. We analyzed proteolysis, lipid peroxidation, tumor diameter and weight. Lipid peroxidation was representative only in the cerebral cortex, where there was more oxidative stress in rats treated with the extract (p = 0.0276). For proteolysis, there was less muscle damage in untreated rats (p = 0.0312). Only tumor diameter in treated rats was significantly lower (p = 0.0200) compared to untreated ones. The açaí seed extract showed no beneficial effect on the general framework of the cachectic syndrome in lab rats. However, some anticarcinogenic effects were observed in the tumor diameter and weight.

Mechanical-Kinetic Modeling of a Molecular Walker from a Modular Design Principle

NASA Astrophysics Data System (ADS)

Hou, Ruizheng; Loh, Iong Ying; Li, Hongrong; Wang, Zhisong

2017-02-01

Artificial molecular walkers beyond burnt-bridge designs are complex nanomachines that potentially replicate biological walkers in mechanisms and functionalities. Improving the man-made walkers up to performance for widespread applications remains difficult, largely because their biomimetic design principles involve entangled kinetic and mechanical effects to complicate the link between a walker's construction and ultimate performance. Here, a synergic mechanical-kinetic model is developed for a recently reported DNA bipedal walker, which is based on a modular design principle, potentially enabling many directional walkers driven by a length-switching engine. The model reproduces the experimental data of the walker, and identifies its performance-limiting factors. The model also captures features common to the underlying design principle, including counterintuitive performance-construction relations that are explained by detailed balance, entropy production, and bias cancellation. While indicating a low directional fidelity for the present walker, the model suggests the possibility of improving the fidelity above 90% by a more powerful engine, which may be an improved version of the present engine or an entirely new engine motif, thanks to the flexible design principle. The model is readily adaptable to aid these experimental developments towards high-performance molecular walkers.

Q&A with Andy Walker: The Ins and Outs of Renewable Energy Optimization |

Science.gov Websites

Optimization April 30, 2018 Profile image of researcher Andy Walker Andy Walker is a research fellow at NREL and the creator of Renewable Energy Optimization. Profile image of researcher Andy Walker Andy Walker is a research fellow at NREL and the creator of Renewable Energy Optimization. Andy Walker is a

Walker in the JPM

NASA Image and Video Library

2010-10-21

ISS025-E-008414 (21 Oct. 2010) --- NASA astronaut Shannon Walker, Expedition 25 flight engineer, works at the Cell Biology Experiment Facility (CBEF) in the Kibo laboratory of the International Space Station.

Temporal triangular alopecia and a review of 52 past cases.

PubMed

Yamazaki, Masashi; Irisawa, Ryokichi; Tsuboi, Ryoji

2010-04-01

Temporal triangular alopecia (TTA) is a circumscribed, non-cicatricial form of alopecia confined to the frontotemporal region. The patient, a 15-year-old boy, was noticed at birth to have an alopecial area, sized 1.5 cm x 2.5 cm, in the right temporal region. Microscopic examination revealed miniaturized hair follicles accompanied by differentiated sebaceous glands. We have provided a synopsis of the past 52 cases. Of the 53 cases of TTA including our case, more than half (55.8%) were detected in childhood between the ages of 2 and 9 years, while 36.5% were detected at birth and only 3.8% (only two cases) in adulthood. There were three familial cases. Several congenital diseases were associated with the condition, for example, phakomatosis pigmentovascularis, Down syndrome and Dandy-Walker malformation. This information suggests that TTA can be recognized as a hamartomatous mosaic disease.

Nonconvergence of the Wang-Landau algorithms with multiple random walkers.

PubMed

Belardinelli, R E; Pereyra, V D

2016-05-01

This paper discusses some convergence properties in the entropic sampling Monte Carlo methods with multiple random walkers, particularly in the Wang-Landau (WL) and 1/t algorithms. The classical algorithms are modified by the use of m-independent random walkers in the energy landscape to calculate the density of states (DOS). The Ising model is used to show the convergence properties in the calculation of the DOS, as well as the critical temperature, while the calculation of the number π by multiple dimensional integration is used in the continuum approximation. In each case, the error is obtained separately for each walker at a fixed time, t; then, the average over m walkers is performed. It is observed that the error goes as 1/sqrt[m]. However, if the number of walkers increases above a certain critical value m>m_{x}, the error reaches a constant value (i.e., it saturates). This occurs for both algorithms; however, it is shown that for a given system, the 1/t algorithm is more efficient and accurate than the similar version of the WL algorithm. It follows that it makes no sense to increase the number of walkers above a critical value m_{x}, since it does not reduce the error in the calculation. Therefore, the number of walkers does not guarantee convergence.

Obituary: Robert Mowbray Walker, 1929-2004

NASA Astrophysics Data System (ADS)

Schoenherr, Neil T.

2004-12-01

Robert M. Walker, PhD, Professor of Physics in Arts & Sciences and a faculty fellow of the McDonnell Center for the Space Sciences, died of stomach cancer Thursday, 12 February 2004, in Brussels, Belgium. He was 75. Walker worked on the frontiers of space research for more than four decades. Robert Walker was born in Philadelphia on 6 February 1929. His mother was Dorothy Potter and he considered Roger Potter his father though he was not his biological father. His early years were spent in New York City and in upstate New York. He attended the Bronx High School of Science, earned his BS in physics from Union College and in 1954, he received his PhD in particle physics from Yale University. He subsequently joined the General Electric Laboratory in Schenectady, New York where he studied the radiation effects in solids. His work on defects in irradiated copper is still regarded as the definitive work on the topic. In the early 1960s, Walker's discovery of fossil nuclear particle tracks in minerals was instrumental to new developments in geo-chronology and cosmic ray physics. In particular, his discovery of tracks from nuclei heavier than iron opened a new frontier of cosmic ray physics. He subsequently pioneered the use of plastics to detect and count such nuclei in cosmic ray balloon flights. Beginning in 1966, when he moved to Washington University and became the first McDonnell Professor of Physics, his research interests turned more toward space physics. He was the inaugural director of the McDonnell Center, which was established in 1975 by a gift from aerospace pioneer James S. McDonnell. Walker was a member of the NASA committee that allocated samples of the first returned lunar materials, and his laboratory led the way in deciphering their record of lunar, solar system and galactic evolution. Together with Ghislaine Crozaz and other colleagues, Walker made path breaking laboratory studies of the first moon rocks revealing the history of solar radiation and

Designing instrumented walker to measure upper-extremity's efforts: A case study.

PubMed

Khodadadi, Mohammad; Baniasad, Mina Arab; Arazpour, Mokhtar; Farahmand, Farzam; Zohoor, Hassan

2018-02-26

The high prevalence of shoulder pain in using walkers in patients who have spinal cord injury (SCI). Also, the limited options available to economically measure grip forces in walkers, which drove the need to create one. This article describes a method to obtain upper-extremities' forces and moments in a person with SCI by designing an appropriate instrumented walker. First, since the commercial multidirectional loadcells are too expensive, custom loadcells are fabricated. Ultimately, a complete gait analysis by means of VICON motion analysis and using inverse dynamic method has been held to measure upper-extremities' efforts. The results for a person with SCI using a two-wheel walker in low and high heights and a basic walker show that there are higher shoulder and elbow flexion-extension moments and also higher shoulder forces in superior-inferior direction and higher elbow and wrist forces in anterior-posterior directions. The results are not much different in using two different types of walker. By using the proposed method, upper-extremities' forces and moments were obtained and the results were compared to each other in using two different walkers.

Walker in the JPM

NASA Image and Video Library

2010-10-21

ISS025-E-008416 (21 Oct. 2010) --- NASA astronaut Shannon Walker, Expedition 25 flight engineer, uses a computer while working at the Cell Biology Experiment Facility (CBEF) in the Kibo laboratory of the International Space Station.

Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA

USGS Publications Warehouse

Yuan, F.; Linsley, B.K.; Howe, S.S.; Lund, S.P.; McGeehin, J.P.

2006-01-01

Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700??years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (> 2400??years B.P.), a lake-filling period (??? 2400 to ??? 1000??years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (??? 1000 to ??? 600??years B.P.), a relatively wet period (??? 600 to ??? 100??years B.P.), and the anthropogenically induced lake-level lowering period (< 100??years B.P.). The most pronounced lowstand of Walker Lake occurred at ??? 2400??years B.P., as indicated by the relatively high values of ??18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400??years B.P. ?? 2006 Elsevier B.V. All rights reserved.

Visible/near-infrared subdiffraction imaging reveals the stochastic nature of DNA walkers

PubMed Central

Pan, Jing; Cha, Tae-Gon; Li, Feiran; Chen, Haorong; Bragg, Nina A.; Choi, Jong Hyun

2017-01-01

DNA walkers are designed with the structural specificity and functional diversity of oligonucleotides to actively convert chemical energy into mechanical translocation. Compared to natural protein motors, DNA walkers’ small translocation distance (mostly <100 nm) and slow reaction rate (<0.1 nm s−1) make single-molecule characterization of their kinetics elusive. An important indication of single-walker kinetics is the rate-limiting reactions that a particular walker design bears. We introduce an integrated super-resolved fluorescence microscopy approach that is capable of long-term imaging to investigate the stochastic behavior of DNA walkers. Subdiffraction tracking and imaging in the visible and second near-infrared spectra resolve walker structure and reaction rates. The distributions of walker kinetics are analyzed using a stochastic model to reveal reaction randomness and the rate-limiting biochemical reaction steps. PMID:28116353

Older homebound women: negotiating reliance on a cane or walker.

PubMed

Porter, Eileen J; Benson, Jacquelyn J; Matsuda, Sandy

2011-04-01

Canes and walkers are commonly characterized as assistive devices that serve the same purpose: as walking aides. These general views were reappraised and tempered in this descriptive phenomenological study with 40 older women (aged 85 to 98 years) who were unable to leave their homes without help. The purpose was to describe the phenomena of negotiating reliance on canes and walkers as walking devices and the lifeworld context underlying each phenomenon. Relative to lifeworld, there were differences between coming to terms with using a cane and coming to terms with using a walker. Data revealed similarities and distinctions between the basic intentions of relying on canes and walkers and the associated purposes served by canes and walkers. Participants did not view either device as consistently assistive. Findings evoke opportunities for dialogue among older persons, scholars, practitioners, and designers of these devices about coming to terms with such devices and relying on them.

Older Homebound Women: Negotiating Reliance on a Cane or Walker

PubMed Central

Porter, Eileen J.; Benson, Jacquelyn J.; Matsuda, Sandy

2012-01-01

Canes and walkers are commonly characterized as assistive devices and as devices that serve the same purpose, as walking aides. These general views were reappraised and tempered in this descriptive phenomenological study with 40 older women (aged 85-98) who were unable to leave their homes without help. The purpose was to describe the phenomena of negotiating reliance on canes and walkers as walking devices and the lifeworld context underlying each phenomenon. Relative to lifeworld, there were differences between coming to terms with using a cane and coming to terms with using a walker. Data revealed similarities and distinctions between the basic intentions of relying on canes and on walkers and the associated purposes served by canes and walkers. Participants did not view either device as consistently assistive. Findings evoke opportunities for dialogue among older persons, scholars, practitioners, and designers of these devices about coming to terms with such devices and relying on them. PMID:21041520

Anthropometric characteristics of top-class Olympic race walkers.

PubMed

Gomez-Ezeiza, Josu; Tam, Nicholas; Torres-Unda, Jon; Granados, Cristina; Santos-Concejero, Jordan

2018-04-20

Typical training programmes in elite race walkers involve high training volumes at low and moderate intensities, which have been reported to induce functional and structural adaptations at an anthropometric level. Since anthropometrical variables are closely related to movement efficiency and performance in endurance events, the aim of this study was to describe the anthropometric profile of world-class race walkers. Twenty-nine world-class race walkers (21 men & 8 women) participated in this study. Anthropometric characteristics, including height, body mass, eight skinfolds, five girths and four bone breadths were measured. Body composition, somatotype, somatotype dispersion mean, somatotype attitudinal mean and height to weight ratio, as well as skinfolds extremity to trunk ratio were also calculated. Mean height, body mass and body mass index were 177.1 ± 7.1 cm, 66.4 ± 5.8 kg, and21.2±1.3kg·m2 formenand165.6±4.5cm,53.6±3.7kg,and19.6±1.6kg·m2for women, respectively. Women presented greater body fat content (6.7 ± 0.6 vs. 12.2 ± 0.8%; very large effect), less muscle mass (65.6 ± 4.6 vs. 61.6 ± 2.6 kg; large effect), and were more endomorphic (large effect) than men. Men specialists in 20-km showed greater muscle mass (66.7 ± 4.9 vs. 64.4 ± 4.3 kg; moderate effect), and slightly higher skinfolds, girths, body fat content and were more mesomorphic than 50-km specialists (moderate effect). The present study expands the limited knowledge on the anthropometric characteristics and somatotype elements of elite top-class race walkers. The characterisation of the morphology of elite race walkers provides coaches a reference values to control the training development of the race walker, as well as providing reference values to improve talent identification.

Four-wheeled walker related injuries in older adults in the Netherlands.

PubMed

van Riel, K M M; Hartholt, K A; Panneman, M J M; Patka, P; van Beeck, E F; van der Cammen, T J M

2014-02-01

With ageing populations worldwide, mobility devices are used more than ever. In the current literature there is no consensus whether the available mobility devices safely improve the mobility of their users. Also, evidence is lacking concerning the risks and types of injuries sustained while using a four-wheeled walker. To assess injury risks and injury patterns in older adults (≥65 years) who presented at Emergency Departments (ED) in the Netherlands with an injury due to using a four-wheeled walker. In this study, the Dutch Injury Surveillance System was used to obtain a national representative sample of annual ED visits in the Netherlands in the adult population (≥65 years) sustaining an injury while using a four-wheeled walker. The numbers of four-wheeled walker users in the Netherlands were obtained from the national insurance board. The numbers of ED visits were divided by the numbers of four-wheeled walker users to calculate age- and sex-specific injury risks. Annually 1869 older adults visited an ED after sustaining an injury while using a four-wheeled walker. Falls were the main cause of injury (96%). The injury risk was 3.1 per 100 users of four-wheeled walkers. Women (3.5 per 100 users) had a higher risk than men (2.0 per 100 users). Injury risk was the highest in women aged 85 years and older (6.2 per 100 users). The majority of injuries were fractures (60%) with hip fracture (25%) being the most common injury. Nearly half of all four-wheeled walker related injuries required hospitalisation, mostly due to hip fractures. Healthcare costs per injury were approximately €12 000. This study presents evidence that older adults experiencing a fall while using a four-wheeled walker are at high risk to suffer severe injuries.

B3GALNT2-Related Dystroglycanopathy: Expansion of the Phenotype with Novel Mutation Associated with Muscle-Eye-Brain Disease, Walker-Warburg Syndrome, Epileptic Encephalopathy-West Syndrome, and Sensorineural Hearing Loss.

PubMed

Al Dhaibani, Muna A; El-Hattab, Ayman W; Ismayl, Omar; Suleiman, Jehan

2018-05-23

Mutations in B3GALNT2 , encoding a glycosyltransferase enzyme involved in α-dystroglycan glycosylation, have been recently associated with dystroglycanopathy, a well-recognized subtype of congenital muscular dystrophy (CMD). Only a few cases have been reported with B3GALNT2 -related dystroglycanopathy with variable severity ranging from mild CMD to severe muscle-eye-brain disease. Here, we describe a child with a novel homozygous nonsense mutation in B3GALNT2 . The affected child has severe neurological disease since birth, including muscle disease manifested as hypotonia, muscle weakness, and wasting with elevated creatine kinase, eye disease including microphthalmia and blindness, brain disease with extensive brain malformations including massive hydrocephalus, diffuse cobblestone-lissencephaly, deformed craniocervical junction, and pontocerebellar hypoplasia. The clinical and radiologic findings are compatible with a diagnosis of severe muscle-eye-brain disease and more specifically Walker-Warburg syndrome. A more distinct aspect of the clinical phenotype in this child is the presence of refractory epilepsy in the form of epileptic spasms, epileptic encephalopathy, and West syndrome, as well as sensorineural hearing loss. These findings could expand the phenotype of B3GALNT2 -related dystroglycanopathy. In this report, we also provide a detailed review of previously reported cases with B3GALNT2 -related dystroglycanopathy and compare them to our reported child. In addition, we study the genotype-phenotype correlation in these cases. Georg Thieme Verlag KG Stuttgart · New York.

A Novel Rasopathy Caused by Recurrent De Novo Missense Mutations In PPP1CB Closely Resembles Noonan Syndrome with Loose Anagen Hair

PubMed Central

Gripp, Karen W.; Aldinger, Kimberly A.; Bennett, James T.; Baker, Laura; Tusi, Jessica; Powell-Hamilton, Nina; Stabley, Deborah; Sol-Church, Katia; Timms, Andrew E.; Dobyns, William B.

2016-01-01

Noonan syndrome is a rasopathy caused by mutations in multiple genes encoding components of the RAS/MAPK pathway. Despite its variable phenotype, limited genotype-phenotype correlations exist. Noonan syndrome with loose anagen hair (NS-LAH) is characterized by its distinctive hair anomalies, developmental differences and structural brain abnormalities and is caused by a single recurrent missense SHOC2 mutation. SHOC2 forms a complex with protein phosphatase 1 (PP1C). Protein phosphatases counterbalance kinases and control activation of signaling proteins, such as the mitogen activated protein kinases of the RAS/MAPK pathway. Here we report four patients with de novo missense mutations in protein phosphatase 1 catalytic subunit beta (PPP1CB), sharing a recognizable phenotype. Three individuals had the recurrent PPP1CB c.146G>C, p.Pro49Arg mutation, the fourth had a c.166G>C, p.Ala56Pro change. All had relative or absolute macrocephaly, low-set and posteriorly angulated ears and developmental delay. Slow growing and/or sparse hair and/or an unruly hair texture was present in all. Three individuals had feeding difficulties requiring feeding tubes. One of two males had cryptorchidism, another had pectus excavatum. Short stature was present in three. A female with the recurrent mutation had a Dandy-Walker malformation and optic nerve hypoplasia. Mild ventriculomegaly occurred in all, cerebellar tonsillar ectopia was seen in two and progressed to Chiari 1 malformation in one individual. Based on the combination of phenotypic findings and PPP1CB’s effect on RAF dephosphorylation within the RAS/MAPK pathway, this novel condition can be considered a rasopathy, most similar to NS-LAH. Collectively, these mutations meet the standardized criteria for pathogenicity. PMID:27264673

A novel rasopathy caused by recurrent de novo missense mutations in PPP1CB closely resembles Noonan syndrome with loose anagen hair.

PubMed

Gripp, Karen W; Aldinger, Kimberly A; Bennett, James T; Baker, Laura; Tusi, Jessica; Powell-Hamilton, Nina; Stabley, Deborah; Sol-Church, Katia; Timms, Andrew E; Dobyns, William B

2016-09-01

Noonan syndrome is a rasopathy caused by mutations in multiple genes encoding components of the RAS/MAPK pathway. Despite its variable phenotype, limited genotype-phenotype correlations exist. Noonan syndrome with loose anagen hair (NS-LAH) is characterized by its distinctive hair anomalies, developmental differences, and structural brain abnormalities and is caused by a single recurrent missense SHOC2 mutation. SHOC2 forms a complex with protein phosphatase 1 (PP1C). Protein phosphatases counterbalance kinases and control activation of signaling proteins, such as the mitogen-activated protein kinases of the RAS/MAPK pathway. Here we report four patients with de novo missense mutations in protein phosphatase one catalytic subunit beta (PPP1CB), sharing a recognizable phenotype. Three individuals had the recurrent PPP1CB c.146G>C, p.Pro49Arg mutation, the fourth had a c.166G>C, p.Ala56Pro change. All had relative or absolute macrocephaly, low-set and posteriorly angulated ears, and developmental delay. Slow growing and/or sparse hair and/or an unruly hair texture was present in all. Three individuals had feeding difficulties requiring feeding tubes. One of two males had cryptorchidism, another had pectus excavatum. Short stature was present in three. A female with the recurrent mutation had a Dandy-Walker malformation and optic nerve hypoplasia. Mild ventriculomegaly occurred in all, cerebellar tonsillar ectopia was seen in two and progressed to Chiari 1 malformation in one individual. Based on the combination of phenotypic findings and PPP1CB's effect on RAF dephosphorylation within the RAS/MAPK pathway, this novel condition can be considered a rasopathy, most similar to NS-LAH. Collectively, these mutations meet the standardized criteria for pathogenicity. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Interaction of two walkers: wave-mediated energy and force.

PubMed

Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

2014-12-01

A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.

Effects of walker gender and observer gender on biological motion walking direction discrimination.

PubMed

Yang, Xiaoying; Cai, Peng; Jiang, Yi

2014-09-01

The ability to recognize the movements of other biological entities, such as whether a person is walking toward you, is essential for survival and social interaction. Previous studies have shown that the visual system is particularly sensitive to approaching biological motion. In this study, we examined whether the gender of walkers and observers influenced the walking direction discrimination of approaching point-light walkers in fine granularity. The observers were presented a walker who walked in different directions and were asked to quickly judge the walking direction (left or right). The results showed that the observers demonstrated worse direction discrimination when the walker was depicted as male than when the walker was depicted as female, probably because the observers tended to perceive the male walkers as walking straight ahead. Intriguingly, male observers performed better than female observers at judging the walking directions of female walkers but not those of male walkers, a result indicating perceptual advantage with evolutionary significance. These findings provide strong evidence that the gender of walkers and observers modulates biological motion perception and that an adaptive perceptual mechanism exists in the visual system to facilitate the survival of social organisms. © 2014 The Institute of Psychology, Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Posterior fossa anomalies diagnosed with fetal MRI: associated anomalies and neurodevelopmental outcomes.

PubMed

Patek, Kyla J; Kline-Fath, Beth M; Hopkin, Robert J; Pilipenko, Valentina V; Crombleholme, Timothy M; Spaeth, Christine G

2012-01-01

The purpose of this study was to describe the relationship between intracranial and extracranial anomalies and neurodevelopmental outcome for fetuses diagnosed with a posterior fossa anomaly (PFA) on fetal MRI. Cases of Dandy-Walker malformation, vermian hypogenesis/hypoplasia, and mega cisterna magna (MCM) were identified through the Fetal Care Center of Cincinnati between January 2004 and December 2010. Parental interview and retrospective chart review were used to assess neurodevelopmental outcome. Posterior fossa anomalies were identified in 59 fetuses; 9 with Dandy-Walker malformation, 36 with vermian hypogenesis/hypoplasia, and 14 with MCM. Cases with isolated PFAs (14/59) had better outcomes than those with additional anomalies (p = 0.00016), with isolated cases of MCM all being neurodevelopmentally normal. Cases with additional intracranial anomalies had a worse outcome than those without intracranial anomalies (p = 0.00017). The presence of extracranial anomalies increased the likelihood of having a poor outcome (p = 0.00014) as did the identification of an abnormal brainstem (p = 0.00018). Intracranial and extracranial anomalies were good predictors of neurodevelopmental outcome in this study. The prognosis was poor for individuals with an abnormal brainstem, whereas those with isolated MCM had normal neurodevelopmental outcome. © 2012 John Wiley & Sons, Ltd.

[Active and safe with wheeled walkers : Pilot study on feasibility of mobility exercises for wheeled walker users].

PubMed

Pflaum, Marina; Lang, Frieder R; Freiberger, Ellen

2016-07-01

The number of older people with mobility impairments using wheeled walkers is increasing; however, the handling of these walking aids is often ineffective. Moreover, age-associated functional loss, environmental demands and fear of falling may additionally challenge mobility. The new training program "Active and safe with wheeled walkers" aims to enhance skills and to improve mobility. The present pilot study was carried out to assess the feasibility of the training as well as to identify training effects and methodological insights for further research. The study was carried out with 28 wheeled walker users (age 68-91 years) in assisted living facilities using a pre-post design. Of the participants 13 persons were trained for 10 weeks (90 min, twice a week) and 15 persons served as a control group. Data were collected on functional mobility, hand strength, leg strength, balance, walker handling and fear of falling. The drop-out rate for the training was 38 % due to health concerns (n = 2), lack of time (n = 1) and changes in health status independent of training (n = 3). Medium to large effects were detected. Data regarding the recruitment strategy and the acceptance of individual exercises are available. The results indicate a good feasibility and effectiveness of the training. The simple accessibility of the training was conducive for the regular participation. The everyday relevance of the results and the lack of comparable interventions suggest that further research efforts be carried out. Recruitment strategies, training requirements and data collection methods need to be optimized.

A stochastic DNA walker that traverses a microparticle surface

NASA Astrophysics Data System (ADS)

Jung, C.; Allen, P. B.; Ellington, A. D.

2016-02-01

Molecular machines have previously been designed that are propelled by DNAzymes, protein enzymes and strand displacement. These engineered machines typically move along precisely defined one- and two-dimensional tracks. Here, we report a DNA walker that uses hybridization to drive walking on DNA-coated microparticle surfaces. Through purely DNA:DNA hybridization reactions, the nanoscale movements of the walker can lead to the generation of a single-stranded product and the subsequent immobilization of fluorescent labels on the microparticle surface. This suggests that the system could be of use in analytical and diagnostic applications, similar to how strand exchange reactions in solution have been used for transducing and quantifying signals from isothermal molecular amplification assays. The walking behaviour is robust and the walker can take more than 30 continuous steps. The traversal of an unprogrammed, inhomogeneous surface is also due entirely to autonomous decisions made by the walker, behaviour analogous to amorphous chemical reaction network computations, which have been shown to lead to pattern formation.

Spacetime emergence of the robertson-walker universe from a matrix model.

PubMed

Erdmenger, Johanna; Meyer, René; Park, Jeong-Hyuck

2007-06-29

Using a novel, string theory-inspired formalism based on a Hamiltonian constraint, we obtain a conformal mechanical system for the spatially flat four-dimensional Robertson-Walker Universe. Depending on parameter choices, this system describes either a relativistic particle in the Robertson-Walker background or metric fluctuations of the Robertson-Walker geometry. Moreover, we derive a tree-level M theory matrix model in this time-dependent background. Imposing the Hamiltonian constraint forces the spacetime geometry to be fuzzy near the big bang, while the classical Robertson-Walker geometry emerges as the Universe expands. From our approach, we also derive the temperature of the Universe interpolating between the radiation and matter dominated eras.

Payload Specialist Charles Walker with handheld protein growth experiment

NASA Image and Video Library

1985-11-26

61B-02-014 (26 Nov-3 Dec 1985) --- Payload Specialist Charles D. Walker works with the handheld protein growth experiment -- one of a series of tests being flown to study the possibility of crystallizing biological materials. Walker rests the experiment against the larger continuous flow electrophoresis systems experiment.

Evapotranspiration from the Lower Walker River Basin, West-Central Nevada, Water Years 2005-07

USGS Publications Warehouse

Allander, Kip K.; Smith, J. LaRue; Johnson, Michael J.

2009-01-01

Evapotranspiration is the ultimate path of outflow of nearly all water from the Lower Walker River basin. Walker Lake is the terminus of the topographically closed Walker River basin, and the lake level has been declining at an average rate of about 1.6 feet per year (ft/yr) since 1917. As a result of the declining lake level, dissolved-solids concentrations are increasingly threatening the fishery and ecosystem health of the lake. Uncertainties in the water budget components of the Lower Walker River basin led the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to undertake an investigation to refine estimates of the water budget. Evapotranspiration from the Lower Walker River basin represents a major component of this water budget. The specific objectives of this report are to provide estimates of total and net evapotranspiration for water years 2005-07 for areas in the Lower Walker River basin in which annual evapotranspiration exceeds annual precipitation, and to summarize these results for areas of similar vegetation and soil characteristics, hydrographic subareas, and Walker Lake and Weber Reservoir. The three hydrographic subareas include the area along Walker River north of Walker Lake, the area of and adjacent to Walker Lake, and the area south of Walker Lake. Areas of annual evapotranspiration exceeding annual precipitation were identified and mapped in the field and were further delineated using remote-sensing analysis. These areas were classified into 10 evapotranspiration units. A network of 11 evapotranspiration stations was operated in natural and agricultural vegetation and on Walker Lake. Measured evapotranspiration rates ranged from 0.5 ft/yr at a sparsely vegetated desert shrub site to 5.0 ft/yr from Walker Lake. The greatest evapotranspiration rate on land was 4.1 ft/yr at an irrigated alfalfa field, and the greatest rate for natural vegetation was 3.9 ft/yr in a riparian community along Walker River. At an

22.5 MB DELETION OF 13q31.1-q34 ASSOCIATED WITH HPE, DWM, AND HSCR: A CASE REPORT AND REDEFINING THE SMALLEST DELETED REGIONS.

PubMed

Alp, M Y; Çebi, A H; Seyhan, S; Cansu, A; Aydin, H; Ikbal, M

2016-01-01

Partial deletion of the long arm of the chromosome 13, 13q deletion syndrome is a rare chromosomal disorder characterized by severe growth and mental retardation, microcephaly, facial dysmorphism, brain malformations (holoprosencephaly, Dandy-Walker malformation), distal limb defects, eye anomalies, genitourinary and gastrointestinal tract malformations (Hirschsprung's disease). Approximately 1.2 Mb region in 13q32 was suggested as minimal critical region which is responsible for severe mental and growth retardation and brain anomalies. Here we described a male patient with de novo interstitial deletion of 13q31.1-q34 associated with short stature, microcephaly, facial dysmorphism, clinodactyly, cryptorchidism, micropenis, epilepsy, HPE, DWM, and HSCR. According to the literature review, present case indicated that smallest deleted region associated with DWM and HPE might be located at the 13q32.3, limb defects 13q34, anogenital malformations 13q33.3-34, and HSCR 13q31.1-32.1.

Supplementation with L-glutamine prevents tumor growth and cancer-induced cachexia as well as restores cell proliferation of intestinal mucosa of Walker-256 tumor-bearing rats.

PubMed

Martins, Heber Amilcar; Sehaber, Camila Caviquioli; Hermes-Uliana, Catchia; Mariani, Fernando Augusto; Guarnier, Flavia Alessandra; Vicentini, Geraldo Emílio; Bossolani, Gleison Daion Piovezana; Jussani, Laraine Almeida; Lima, Mariana Machado; Bazotte, Roberto Barbosa; Zanoni, Jacqueline Nelisis

2016-12-01

This study aimed to evaluate the intestinal mucosa of the duodenum and jejunum of Walker-256 tumor-bearing rats supplemented with L-glutamine. Thirty-two male 50-day-old Wistar rats (Rattus norvegicus) were randomly divided into four groups: control (C), control supplemented with 2 % L-glutamine (GC), Walker-256 tumor (WT), and Walker-256 tumor supplemented with 2 % L-glutamine (TWG). Walker-256 tumor was induced by inoculation viable tumor cells in the right rear flank. After 10 days, celiotomy was performed and duodenal and jejunal tissues were removed and processed. We evaluated the cachexia index, proliferation index, villus height, crypt depth, total height of the intestinal wall, and number of goblet cells by the technique of periodic acid-Schiff (PAS). Induction of Walker-256 tumor promoted a reduction of metaphase index in the TW group animals, which was accompanied by a reduction in the villous height and crypt depths, resulting in atrophy of the intestinal wall as well as increased PAS-positive goblet cells. Supplementation with L-glutamine reduced the tumor growth and inhibited the development of the cachectic syndrome in animals of the TWG group. Furthermore, amino acid supplementation promoted beneficial effects on the intestinal mucosa in the TWG animals through restoration of the number of PAS-positive goblet cells. Therefore, supplementation with 2 % L-glutamine exhibited a promising role in the prevention of tumor growth and cancer-associated cachexia as well as restoring the intestinal mucosa in the duodenum and jejunum of Walker-256 tumor-bearing rats.

Effects of aging on identifying emotions conveyed by point-light walkers.

PubMed

Spencer, Justine M Y; Sekuler, Allison B; Bennett, Patrick J; Giese, Martin A; Pilz, Karin S

2016-02-01

The visual system is able to recognize human motion simply from point lights attached to the major joints of an actor. Moreover, it has been shown that younger adults are able to recognize emotions from such dynamic point-light displays. Previous research has suggested that the ability to perceive emotional stimuli changes with age. For example, it has been shown that older adults are impaired in recognizing emotional expressions from static faces. In addition, it has been shown that older adults have difficulties perceiving visual motion, which might be helpful to recognize emotions from point-light displays. In the current study, 4 experiments were completed in which older and younger adults were asked to identify 3 emotions (happy, sad, and angry) displayed by 4 types of point-light walkers: upright and inverted normal walkers, which contained both local motion and global form information; upright scrambled walkers, which contained only local motion information; and upright random-position walkers, which contained only global form information. Overall, emotion discrimination accuracy was lower in older participants compared with younger participants, specifically when identifying sad and angry point-light walkers. In addition, observers in both age groups were able to recognize emotions from all types of point-light walkers, suggesting that both older and younger adults are able to recognize emotions from point-light walkers on the basis of local motion or global form. (c) 2016 APA, all rights reserved).

Fostering locomotor behavior of children with developmental disabilities: An overview of studies using treadmills and walkers with microswitches.

PubMed

Lancioni, Giulio E; Singh, Nirbhay N; O'Reilly, Mark F; Sigafoos, Jeff; Didden, Robert; Manfredi, Francesco; Putignano, Pietro; Stasolla, Fabrizio; Basili, Gabriella

2009-01-01

This paper provides an overview of studies using programs with treadmills or walkers with microswitches and contingent stimulation to foster locomotor behavior of children with developmental disabilities. Twenty-six studies were identified in the period 2000-2008 (i.e., the period in which research in this area has actually taken shape). Twenty-one of the studies involved the use of treadmills (i.e., 13 were aimed at children with cerebral palsy, 6 at children with Down syndrome, and 2 at children with Rett syndome or cerebellar ataxia). The remaining five studies concerned the use of walkers with microswitches and contingent stimulation with children with multiple disabilities. The outcomes of the studies tended to be positive but occasional failures also occurred. The outcomes were analyzed considering the characteristics of the approaches employed, the implications of the approaches for the participants' overall functioning situation (development), as well as methodological and practical aspects related to those approaches. Issues for future research were also examined.

Optimizing DNA nanotechnology through coarse-grained modeling: a two-footed DNA walker.

PubMed

Ouldridge, Thomas E; Hoare, Rollo L; Louis, Ard A; Doye, Jonathan P K; Bath, Jonathan; Turberfield, Andrew J

2013-03-26

DNA has enormous potential as a programmable material for creating artificial nanoscale structures and devices. For more complex systems, however, rational design and optimization can become difficult. We have recently proposed a coarse-grained model of DNA that captures the basic thermodynamic, structural, and mechanical changes associated with the fundamental process in much of DNA nanotechnology, the formation of duplexes from single strands. In this article, we demonstrate that the model can provide powerful insight into the operation of complex nanotechnological systems through a detailed investigation of a two-footed DNA walker that is designed to step along a reusable track, thereby offering the possibility of optimizing the design of such systems. We find that applying moderate tension to the track can have a large influence on the operation of the walker, providing a bias for stepping forward and helping the walker to recover from undesirable overstepped states. Further, we show that the process by which spent fuel detaches from the walker can have a significant impact on the rebinding of the walker to the track, strongly influencing walker efficiency and speed. Finally, using the results of the simulations, we propose a number of modifications to the walker to improve its operation.

Development of the SORRI-BAURU Posterior Walker.

PubMed

Nicholl, Anthony R J; Busnardo, Renato G; da Silva, Luciana M; Rodrigues, Ana Cláudia T; Luz, Fernanda R C; Bentim, Claudia C G; Medola, Fausto O; Paschoarelli, Luis C

2015-01-01

This study aimed to report on the design and development of a low cost Reverse Walker through a participative development cycle with people undergoing rehabilitation. The creation and fundamentals of the concept are described, as well as the development of prototypes and their provision to subjects with mobility problems. The Reverse Walker benefits the user by promoting a more upright posture and favoring the development of postural balance. Enhancing the mobility of people with disabilities may benefit their independence, social participation and quality of life.

The infant walker: an unappreciated household hazard.

PubMed

Marcella, S; McDonald, B

1990-03-01

The potential for infant walkers to cause injury to infants was demonstrated by the results of a survey of the practicing pediatricians in the state of Connecticut. There was a significant number of severe injuries reported. In addition, seven cases of infants hospitalized at Bridgeport Hospital because of injuries sustained while using an infant walker are included. The survey indicated adequate knowledge of the apparent danger by the practicing physicians, including discussion during anticipatory guidance. Despite this knowledge and guidance, significant morbidity continues to occur.

Design Principles of DNA Enzyme-Based Walkers: Translocation Kinetics and Photoregulation.

PubMed

Cha, Tae-Gon; Pan, Jing; Chen, Haorong; Robinson, Heather N; Li, Xiang; Mao, Chengde; Choi, Jong Hyun

2015-07-29

Dynamic DNA enzyme-based walkers complete their stepwise movements along the prescribed track through a series of reactions, including hybridization, enzymatic cleavage, and strand displacement; however, their overall translocation kinetics is not well understood. Here, we perform mechanistic studies to elucidate several key parameters that govern the kinetics and processivity of DNA enzyme-based walkers. These parameters include DNA enzyme core type and structure, upper and lower recognition arm lengths, and divalent metal cation species and concentration. A theoretical model is developed within the framework of single-molecule kinetics to describe overall translocation kinetics as well as each reaction step. A better understanding of kinetics and design parameters enables us to demonstrate a walker movement near 5 μm at an average speed of ∼1 nm s(-1). We also show that the translocation kinetics of DNA walkers can be effectively controlled by external light stimuli using photoisomerizable azobenzene moieties. A 2-fold increase in the cleavage reaction is observed when the hairpin stems of enzyme catalytic cores are open under UV irradiation. This study provides general design guidelines to construct highly processive, autonomous DNA walker systems and to regulate their translocation kinetics, which would facilitate the development of functional DNA walkers.

Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Central Nevada

USGS Publications Warehouse

Lopes, Thomas J.; Allander, Kip K.

2009-01-01

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes the hydrologic setting of the Walker River basin and a conceptual hydrologic model of the relations among streams, groundwater, and Walker Lake with emphasis on the lower Walker River basin from Wabuska to Hawthorne, Nevada. The Walker River basin is about 3,950 square miles and straddles the California-Nevada border. Most streamflow originates as snowmelt in the Sierra Nevada. Spring runoff from the Sierra Nevada typically reaches its peak during late May to early June with as much as 2,800 cubic feet per second in the Walker River near Wabuska. Typically, 3 to 4 consecutive years of below average streamflow are followed by 1 or 2 years of average or above average streamflow. Mountain ranges are comprised of consolidated rocks with low hydraulic conductivities, but consolidated rocks transmit water where fractured. Unconsolidated sediments include fluvial deposits along the active channel of the Walker River, valley floors, alluvial slopes, and a playa. Sand and gravel deposited by the Walker River likely are discontinuous strata throughout the valley floor. Thick clay strata likely were deposited in Pleistocene Lake Lahontan and are horizontally continuous, except where strata have been eroded by the Walker River. At Walker Lake, sediments mostly are clay interbedded with alluvial slope, fluvial, and deltaic deposits along the lake margins. Coarse sediments form a multilayered, confined-aquifer system that could extend several miles from the shoreline

Can use of walkers or canes impede lateral compensatory stepping movements?

PubMed

Bateni, Hamid; Heung, Evelyn; Zettel, John; McLlroy, William E; Maki, Brian E

2004-08-01

Although assistive devices, such as walkers and canes are often prescribed to aid in balance control, recent studies have suggested that such devices may actually increase risk of falling. In this study, we investigated one possible mechanism: the potential for walkers or canes to interfere with, or constrain, lateral movement of the feet and thereby impede execution of compensatory stepping reactions during lateral loss of balance. Lateral stepping reactions were evoked, in 10 healthy young adults (ages 22-27 years), by means of sudden unpredictable medio-lateral support surface translation. Subjects were tested while holding and loading a standard pickup walker or single-tip cane or while using no assistive device (hands free or holding an object). Results supported the hypothesis that using a walker or cane can interfere with compensatory stepping. Collisions between the swing-foot and mobility aid were remarkably frequent when using the walker (60% of stepping reactions) and also occurred in cane trials (11% of stepping reactions). Furthermore, such collisions were associated with a significant reduction (26-37%) in lateral step length. It appeared that subjects were sometimes able to avoid collision by increasing the forward or backward displacement of the swing-foot or by moving the cane; however, attempts to lift the walker out of the way occurred rarely and were usually impeded due to collision between the contralateral walker post and stance foot. The fact that compensatory stepping behavior was altered significantly in such a healthy cohort clearly demonstrates some of the safety limitations inherent to these assistive devices, as currently designed. Copyright 2003 Elsevier B.V.

DNA Walkers as Transport Vehicles of Nanoparticles Along a Carbon Nanotube Track.

PubMed

Pan, Jing; Cha, Tae-Gon; Chen, Haorong; Li, Feiran; Choi, Jong Hyun

2017-01-01

DNA-based molecular motors are synthetic analogs of naturally occurring protein motors. Typical DNA walkers are constructed from synthetic short DNA strands and are powered by various free energy changes during hybridization reactions. Due to the constraints set by their small physical dimension and slow kinetics, most DNA walkers are characterized by ensemble measurements that result in averaged kinetics data. Here we present a synthetic DNA walker system that exploits the extraordinary physicochemical properties of nanomaterials and the functionalities of DNA molecules, which enables real-time control and monitoring of single-DNA walkers over an extended period.

Fraction of uninfected walkers in the one-dimensional Potts model

NASA Astrophysics Data System (ADS)

O'Donoghue, S. J.; Bray, A. J.

2002-05-01

The dynamics of the one-dimensional q-state Potts model, in the zero-temperature limit, can be formulated through the motion of random walkers which either annihilate (A+A-->∅) or coalesce (A+A-->A) with a q-dependent probability. We consider all of the walkers in this model to be mutually infectious. Whenever two walkers meet, they experience mutual contamination. Walkers which avoid an encounter with another random walker up to time t remain uninfected. The fraction of uninfected walkers is known to obey a power-law decay U(t)~t-φ(q), with a nontrivial exponent φ(q) [C. Monthus, Phys. Rev. E 54, 4844 (1996); S. N. Majumdar and S. J. Cornell, ibid. 57, 3757 (1998)]. We probe the numerical values of φ(q) to a higher degree of accuracy than previous simulations and relate the exponent φ(q) to the persistence exponent θ(q) [B. Derrida, V. Hakim, and V. Pasquier, Phys. Rev. Lett. 75, 751 (1995)], through the relation φ(q)=γ(q)θ(q) where γ is an exponent introduced in [S. J. O'Donoghue and A. J. Bray, preceding paper, Phys. Rev. E 65, XXXX (2002)]. Our study is extended to include the coupled diffusion-limited reaction A+A-->B, B+B-->A in one dimension with equal initial densities of A and B particles. We find that the density of walkers decays in this model as ρ(t)~t-1/2. The fraction of sites unvisited by either an A or a B particle is found to obey a power law, P(t)~t-θ with θ~=1.33. We discuss these exponents within the context of the q-state Potts model and present numerical evidence that the fraction of walkers which remain uninfected decays as U(t)~t-φ, where φ~=1.13 when infection occurs between like particles only, and φ~=1.93 when we also include cross-species contamination. We find that the relation between φ and θ in this model can also be characterized by an exponent γ, where similarly, φ=γθ.

[Cutaneous hemangiomas and vascular malformations and associated pathology (Pascual-Castroviejo type II syndrome). Study of 41 patients].

PubMed

Pascual-Castroviejo, I; Pascual-Pascual, S I; Velázquez-Fragua, R; García, L; López-Gutiérrez, J C; Viaño-López, J; Martínez, V; Palencia, R

To describe the clinical, diagnostic and therapeutic features of this angiomatous neurocutaneous syndrome, which is the most frequent one, and to report a personal series of 41 patients. Forty one patients--31 females and 10 males--were studied during childhood and then, several patients were followed during many years, which allowed us to learn about the evolution of the abnormalities. The cutaneous lesions were classified as hemangiomas in 30 patients (73%) and as vascular malformations in 11 patients (27%). A cerebellar anomaly (unilateral hemispheric hypoplasia and Dandy-Walker malformation) was seen in 13 patients (31.5%) cerebral cortical dysplasia in 4 patients (10%), aortic arch coarctation in 6 patients (15%), and congenital cardiopathy in 5 patients (12%). The most frequent abnormalities were intracranial and/or extracranial vascular malformations. Persistence of the trigeminal artery was observed in 7 patients (17%), absence or severe hypoplasia of an internal carotid artery in 13 patients (32%), absence of a vertebral artery in 7 patients (17%), hypoplasia of intracranial arteries in 6 patients (15%) and aneurysmal enlargement of carotid or vertebral arteries in 5 patients (12%). Also were observed 4 patients (10%) with intracranial hemangioma, 2 (5%) with hemangioma in mediastinum, and 3 (7.5%) with intestinal hemangioma, all of which disappeared during the first years of life. Aneurysmal enlargement of the carotid and vertebral arteries and intracranial branches also disappeared after a process of progressive narrowing of the arterial lumen that caused complete obstruction of these arteries. At the same time the cutaneous hemangioma regressed. During this process, collateral vascularization through branches of the external carotid artery and of the non-affected branches of the contralateral intracranial arteries developed. This neurocutaneous syndrome is the most frequent one and it is associated with several types of vascular and non

Petri-net-based 2D design of DNA walker circuits.

PubMed

Gilbert, David; Heiner, Monika; Rohr, Christian

2018-01-01

We consider localised DNA computation, where a DNA strand walks along a binary decision graph to compute a binary function. One of the challenges for the design of reliable walker circuits consists in leakage transitions, which occur when a walker jumps into another branch of the decision graph. We automatically identify leakage transitions, which allows for a detailed qualitative and quantitative assessment of circuit designs, design comparison, and design optimisation. The ability to identify leakage transitions is an important step in the process of optimising DNA circuit layouts where the aim is to minimise the computational error inherent in a circuit while minimising the area of the circuit. Our 2D modelling approach of DNA walker circuits relies on coloured stochastic Petri nets which enable functionality, topology and dimensionality all to be integrated in one two-dimensional model. Our modelling and analysis approach can be easily extended to 3-dimensional walker systems.

33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone: Walkers Point, Kennebunkport ME. 165.102 Section 165.102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Zone: Walkers Point, Kennebunkport ME. (a) Location. The following area is a security zone: From point...

33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone: Walkers Point, Kennebunkport ME. 165.102 Section 165.102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Zone: Walkers Point, Kennebunkport ME. (a) Location. The following area is a security zone: From point...

33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone: Walkers Point, Kennebunkport ME. 165.102 Section 165.102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Zone: Walkers Point, Kennebunkport ME. (a) Location. The following area is a security zone: From point...

33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone: Walkers Point, Kennebunkport ME. 165.102 Section 165.102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Zone: Walkers Point, Kennebunkport ME. (a) Location. The following area is a security zone: From point...

Vertical force and wrist deviation angle in a sample of elderly people using walkers.

PubMed

Leung, Cherng-Yee; Yeh, Po-Chan

2013-02-01

Walkers are frequently used by elderly people with weak lower limbs and limited balance, but the ergonomic relationship between the use of a walker and stress on the upper limbs is relatively unstudied. The current study assessed wrist deviation and vertical force among elderly individuals using a walker for assistance in walking. 60 elderly volunteers (M age = 81.0 yr., SD = 8.8) participated, 30 of whom frequently used a walker, and 30 who had no such prior experience. Data were obtained from four load cells and a twin-axis wrist goniometer during assisted ambulation using the walker. No significant group difference was found in gait cycle. Significant wrist deviation occurred, with ulnar deviation/dorsiflexion of the right hand, which was greater than that of the left. Non-experienced participants had larger dorsiflexion than experienced participants. Experienced participants produced larger vertical force than non-experienced participants. The greaterthe wrist deviation, the greater was the vertical force. The horizontal handles of most marketed walkers cause wrist deviations. This is a concern for users, clinicians, and related industries. Improvements in walker design should be considered.

Promoting child safety in primary care: a cluster randomised controlled trial to reduce baby walker use.

PubMed

Kendrick, Denise; Illingworth, Rachel; Woods, Amanda; Watts, Kim; Collier, Jacqueline; Dewey, Michael; Hapgood, Rhydian; Chen, Chih-Mei

2005-08-01

Baby walkers are commonly used items of nursery equipment, but cause more than 3000 injuries each year in the UK. There is currently little evidence regarding the effectiveness of interventions in primary care to reduce walker use. To evaluate the effectiveness of an educational package provided by midwives and health visitors to reduce baby walker possession and use. Cluster randomised controlled trial. Sixty-four general practices in Nottingham and North Nottinghamshire, UK. An educational package aimed at discouraging mothers-to-be from obtaining and using a walker was delivered by midwives and health visitors to 1174 mothers-to-be of at least 28 weeks gestation. The control arm received usual care. Primary outcome measures were the possession and use of a walker. Secondary outcome measures included the frequency and duration of walker use, knowledge and attitudes towards walkers, plans to use a walker with future children, recommending a walker to a friend, and use of stair gates and fire guards. Intervention arm participants were significantly less likely to own (odds ratio [OR] = 0.63, 95% confidence interval [CI] = 0.43 to 0.93) or to use a walker (OR = 0.26, 95% CI = 0.08 to 0.84). They were significantly less likely to plan to use a walker with their next child (OR = 0.52, 95% CI = 0.31 to 0.86) or to agree that walkers keep children safe (OR = 0.35, 95% CI = 0.16 to 0.78). There was some evidence that they were less likely to recommend a walker to a friend (OR = 0.51, 95% CI = 0.28 to 0.91) or to agree that they help children to walk more quickly (OR = 0.53, 95% CI = 0.29 to 0.95). An educational package delivered by midwives and health visitors was effective in reducing baby walker possession and use. Providers of primary healthcare services should include baby walker education in their injury prevention strategy and child health promotion programme.

STS-69 Mission Commander David M. Walker suits up

NASA Technical Reports Server (NTRS)

1995-01-01

STS-69 Mission Commander David M. Walker signals he's ready to fly as he finishes donning his launch/entry suit in the Operations and Checkout Building. Walker, who is embarking on his fourth trip into space, will depart shortly for Launch Pad 39A along with four fellow crew members. Awaiting the crew and liftoff at 11:09 a.m. EDT is the Space Shuttle Endeavour.

75 FR 35265 - Safety Standard for Infant Walkers: Final Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-21

... application, the maximum allowable displacement (i.e., movement) of the walker is 1.97 inches. The commenter... advocated increasing the maximum allowable displacement to 6 inches in accordance with ASTM F 2012. Response... playing with toys. The parking brake performance test should set limits on the displacement of the walker...

Sex difference in attractiveness perceptions of strong and weak male walkers.

PubMed

Fink, Bernhard; André, Selina; Mines, Johanna S; Weege, Bettina; Shackelford, Todd K; Butovskaya, Marina L

2016-11-01

Men and women accurately assess male physical strength from facial and body morphology cues. Women's assessments of male facial attractiveness, masculinity, and dominance correlate positively with male physical strength. A positive relationship also has been reported between physical strength and attractiveness of men's dance movements. Here, we investigate men's and women's attractiveness, dominance, and strength assessments from brief samples of male gait. Handgrip strength (HGS) was measured in 70 heterosexual men and their gait was motion-captured. Men and women judged 20 precategorized strong (high HGS) and weak (low HGS) walkers on attractiveness, dominance, and strength, and provided a measure of their own HGS. Both men and women judged strong walkers higher on dominance and strength than weak walkers. Women but not men judged strong walkers more attractive than weak walkers. These effects were independent of observers' physical strength. Male physical strength is conveyed not only through facial and body morphology, but also through body movements. We discuss our findings with reference to studies suggesting that physical strength provides information about male quality in contexts of inter- and intrasexual selection. Am. J. Hum. Biol. 28:913-917, 2016. © 2016Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A new walker with upper trunk suspension system for severely disabled patients.

PubMed

Scoppetta, C; Scoppetta, M

2013-10-01

We have recently designed a new type of walker for those severely disabled patients who cannot walk with commonly used medical walkers. A drawing and the description of this new walker is reported in order to permit the worldwide companies as well as artisans to develop and produce it for the people affected from severe motor problems. This walker supposes the patient wearing either a modified climbing harness or equipped clothes and being suspended to the walking frame. It consists in two series of bands suspending the patient from the frame; the upper one suspends him for the upper part of his trunk, the lower one by his pelvis. This walker is suggested for patients belonging to three principal groups: (1) Persons who have no trunk control (e.g.: patients affected by severe stroke or ataxias). (2) Persons whose walk is allowed only if they achieve a significant reduction (up to 30-40%) of the their body weight charging on trunk, spine, and lower limbs. (3) Persons who need a differentiated reduction of the body weight either among anterior and posterior side or among their right and left part of the body (hemiparesis, Parkinson disease, scoliosis, kyphosis). Creating this walker is easy; producing costs are low; there are no maintenance costs.

Ordering statistics of four random walkers on a line

NASA Astrophysics Data System (ADS)

Helenbrook, Brian; ben-Avraham, Daniel

2018-05-01

We study the ordering statistics of four random walkers on the line, obtaining a much improved estimate for the long-time decay exponent of the probability that a particle leads to time t , Plead(t ) ˜t-0.91287850 , and that a particle lags to time t (never assumes the lead), Plag(t ) ˜t-0.30763604 . Exponents of several other ordering statistics for N =4 walkers are obtained to eight-digit accuracy as well. The subtle correlations between n walkers that lag jointly, out of a field of N , are discussed: for N =3 there are no correlations and Plead(t ) ˜Plag(t) 2 . In contrast, our results rule out the possibility that Plead(t ) ˜Plag(t) 3 for N =4 , although the correlations in this borderline case are tiny.

Development and evaluation of low-cost walker with trunk support for senior citizen.

PubMed

Poier, Paloma Hohmann; Godke, Francisco; Foggiatto, José Aguiomar; Ulbricht, Leandra

2017-10-09

Develop and evaluate a low-cost walker with trunk support for senior citizens. Two-stage descriptive study: development of a walker with trunk support and evaluation with fourth age senior citizens. Twenty-three fourth age senior citizens were selected. The evaluated criteria were the immediate influence of the walker on the static stabilometry with baropodometer and the evaluation of gait with accelerometers monitoring time and amplitude of the hip movement. There was a significant decrease in the body oscillation of senior citizens with the use of the developed walker, and there were changes in the joint amplitudes of the hip, but they were not significant. Using low-cost materials, it was possible to develop and equipment that met resistance and effectiveness requirements. The walker interfered in the balance of the senior citizens, reducing significantly the static body oscillation.

Auditory perception of a human walker.

PubMed

Cottrell, David; Campbell, Megan E J

2014-01-01

When one hears footsteps in the hall, one is able to instantly recognise it as a person: this is an everyday example of auditory biological motion perception. Despite the familiarity of this experience, research into this phenomenon is in its infancy compared with visual biological motion perception. Here, two experiments explored sensitivity to, and recognition of, auditory stimuli of biological and nonbiological origin. We hypothesised that the cadence of a walker gives rise to a temporal pattern of impact sounds that facilitates the recognition of human motion from auditory stimuli alone. First a series of detection tasks compared sensitivity with three carefully matched impact sounds: footsteps, a ball bouncing, and drumbeats. Unexpectedly, participants were no more sensitive to footsteps than to impact sounds of nonbiological origin. In the second experiment participants made discriminations between pairs of the same stimuli, in a series of recognition tasks in which the temporal pattern of impact sounds was manipulated to be either that of a walker or the pattern more typical of the source event (a ball bouncing or a drumbeat). Under these conditions, there was evidence that both temporal and nontemporal cues were important in recognising theses stimuli. It is proposed that the interval between footsteps, which reflects a walker's cadence, is a cue for the recognition of the sounds of a human walking.

Asymptotic shape of the region visited by an Eulerian walker.

PubMed

Kapri, Rajeev; Dhar, Deepak

2009-11-01

We study an Eulerian walker on a square lattice, starting from an initial randomly oriented background using Monte Carlo simulations. We present evidence that, for a large number of steps N , the asymptotic shape of the set of sites visited by the walker is a perfect circle. The radius of the circle increases as N1/3, for large N , and the width of the boundary region grows as Nalpha/3, with alpha=0.40+/-0.06 . If we introduce stochasticity in the evolution rules, the mean-square displacement of the walker, approximately approximately N2nu, shows a crossover from the Eulerian (nu=1/3) to a simple random-walk (nu=1/2) behavior.

LCP method for a planar passive dynamic walker based on an event-driven scheme

NASA Astrophysics Data System (ADS)

Zheng, Xu-Dong; Wang, Qi

2018-06-01

The main purpose of this paper is to present a linear complementarity problem (LCP) method for a planar passive dynamic walker with round feet based on an event-driven scheme. The passive dynamic walker is treated as a planar multi-rigid-body system. The dynamic equations of the passive dynamic walker are obtained by using Lagrange's equations of the second kind. The normal forces and frictional forces acting on the feet of the passive walker are described based on a modified Hertz contact model and Coulomb's law of dry friction. The state transition problem of stick-slip between feet and floor is formulated as an LCP, which is solved with an event-driven scheme. Finally, to validate the methodology, four gaits of the walker are simulated: the stance leg neither slips nor bounces; the stance leg slips without bouncing; the stance leg bounces without slipping; the walker stands after walking several steps.

LCP method for a planar passive dynamic walker based on an event-driven scheme

NASA Astrophysics Data System (ADS)

Zheng, Xu-Dong; Wang, Qi

2018-02-01

The main purpose of this paper is to present a linear complementarity problem (LCP) method for a planar passive dynamic walker with round feet based on an event-driven scheme. The passive dynamic walker is treated as a planar multi-rigid-body system. The dynamic equations of the passive dynamic walker are obtained by using Lagrange's equations of the second kind. The normal forces and frictional forces acting on the feet of the passive walker are described based on a modified Hertz contact model and Coulomb's law of dry friction. The state transition problem of stick-slip between feet and floor is formulated as an LCP, which is solved with an event-driven scheme. Finally, to validate the methodology, four gaits of the walker are simulated: the stance leg neither slips nor bounces; the stance leg slips without bouncing; the stance leg bounces without slipping; the walker stands after walking several steps.

Helen M. Walker: Influential in 1929 and Still Cited Today.

ERIC Educational Resources Information Center

Rice, Marti H.; Stallings, William M.

Helen M. Walker contributed to the field of educational research and statistics during a 55-year career. Born in Iowa in 1891, Walker earned a bachelor's degree from Iowa Wesleyan College and taught high school mathematics for nine years. She then taught at the University of Kansas while doing graduate work. One source noted that she was the first…

Joe Walker in pressure suit with X-1E

NASA Technical Reports Server (NTRS)

1958-01-01

Joe Walker in a pressure suit beside the X-1E at the NASA High-Speed Flight Station, Edwards,California. The dice and 'Little Joe' are prominently displayed under the cockpit area. (Little Joe is a dice players slang term for two deuces.) Walker is shown in the photo wearing an early Air Force partial pressure suit. This protected the pilot if cockpit pressure was lost above 50,000 feet. Similar suits were used in such aircraft as B-47s, B-52s, F-104s, U-2s, and the X-2 and D-558-II research aircraft. Five years later, Walker reached 354,200 feet in the X-15. Similar artwork - reading 'Little Joe the II' - was applied for the record flight. These cases are two of the few times that research aircraft carried such nose art.

Joe Walker in pressure suit with X-1E

NASA Image and Video Library

1958-01-27

Joe Walker in a pressure suit beside the X-1E at the NASA High-Speed Flight Station, Edwards,California. The dice and "Little Joe" are prominently displayed under the cockpit area. (Little Joe is a dice players slang term for two deuces.) Walker is shown in the photo wearing an early Air Force partial pressure suit. This protected the pilot if cockpit pressure was lost above 50,000 feet. Similar suits were used in such aircraft as B-47s, B-52s, F-104s, U-2s, and the X-2 and D-558-II research aircraft. Five years later, Walker reached 354,200 feet in the X-15. Similar artwork - reading "Little Joe the II" - was applied for the record flight. These cases are two of the few times that research aircraft carried such nose art.

Assistive devices alter gait patterns in Parkinson disease: advantages of the four-wheeled walker.

PubMed

Kegelmeyer, Deb A; Parthasarathy, Sowmya; Kostyk, Sandra K; White, Susan E; Kloos, Anne D

2013-05-01

Gait abnormalities are a hallmark of Parkinson's disease (PD) and contribute to fall risk. Therapy and exercise are often encouraged to increase mobility and decrease falls. As disease symptoms progress, assistive devices are often prescribed. There are no guidelines for choosing appropriate ambulatory devices. This unique study systematically examined the impact of a broad range of assistive devices on gait measures during walking in both a straight path and around obstacles in individuals with PD. Quantitative gait measures, including velocity, stride length, percent swing and double support time, and coefficients of variation were assessed in 27 individuals with PD with or without one of six different devices including canes, standard and wheeled walkers (two, four or U-Step). Data were collected using the GAITRite and on a figure-of-eight course. All devices, with the exception of four-wheeled and U-Step walkers significantly decreased gait velocity. The four-wheeled walker resulted in less variability in gait measures and had less impact on spontaneous unassisted gait patterns. The U-Step walker exhibited the highest variability across all parameters followed by the two-wheeled and standard walkers. Higher variability has been correlated with increased falls. Though subjects performed better on a figure-of-eight course using either the four-wheeled or the U-Step walker, the four-wheeled walker resulted in the most consistent improvement in overall gait variables. Laser light use on a U-Step walker did not improve gait measures or safety in figure-of-eight compared to other devices. Of the devices tested, the four-wheeled-walker offered the most consistent advantages for improving mobility and safety. Copyright © 2012 Elsevier B.V. All rights reserved.

Simulation of the Lower Walker River Basin hydrologic system, west-central Nevada, using PRMS and MODFLOW models

USGS Publications Warehouse

Allander, Kip K.; Niswonger, Richard G.; Jeton, Anne E.

2014-01-01

The effects of fallowing of Walker River Indian Irrigation Project fields from 2007 to 2010 on Walker Lake inflow, level, and dissolved solids were evaluated. Fallowing resulted in a near doubling of Walker River inflow to Walker Lake during this period, an increase in Walker Lake level of about 1.4 feet, and a decrease in dissolved-solids concentration of about 540 mg/L.

Comparison of upper extremity kinematics in children with spastic diplegic cerebral palsy using anterior and posterior walkers.

PubMed

Strifling, Kelly M B; Lu, Na; Wang, Mei; Cao, Kevin; Ackman, Jeffrey D; Klein, John P; Schwab, Jeffrey P; Harris, Gerald F

2008-10-01

This prospective study analyzes the upper extremity kinematics of 10 children with spastic diplegic cerebral palsy using anterior and posterior walkers. Although both types of walkers are commonly prescribed by clinicians, no quantitative data comparing the two in regards to upper extremity motion has been published. The study methodology included testing of each subject with both types of walkers in a motion analysis laboratory after an acclimation period of at least 1 month. Overall results showed that statistically, both walkers are relatively similar. With both anterior and posterior walkers, the shoulders were extended, elbows flexed, and wrists extended. Energy expenditure, walking speed and stride length was also similar with both walker types. Several differences were also noted although not statistically significant. Anterior torso tilt was reduced with the posterior walker and shoulder extension and elbow flexion were increased. Outcomes analysis indicated that differences in upper extremity torso and joint motion were not dependent on spasticity or hand dominance. These findings may help to build an understanding of upper extremity motion in walker-assisted gait and potentially to improve walker prescription.

Terrain interaction with the quarter scale beam walker

NASA Technical Reports Server (NTRS)

Chun, Wendell H.; Price, S.; Spiessbach, A.

1990-01-01

Frame walkers are a class of mobile robots that are robust and capable mobility platforms. Variations of the frame walker robot are in commercial use today. Komatsu Ltd. of Japan developed the Remotely Controlled Underwater Surveyor (ReCUS) and Normed Shipyards of France developed the Marine Robot (RM3). Both applications of the frame walker concept satisfied robotic mobility requirements that could not be met by a wheeled or tracked design. One vehicle design concept that falls within this class of mobile robots is the walking beam. A one-quarter scale prototype of the walking beam was built by Martin Marietta to evaluate the potential merits of utilizing the vehicle as a planetary rover. The initial phase of prototype rover testing was structured to evaluate the mobility performance aspects of the vehicle. Performance parameters such as vehicle power, speed, and attitude control were evaluated as a function of the environment in which the prototype vehicle was tested. Subsequent testing phases will address the integrated performance of the vehicle and a local navigation system.

Terrain Interaction With The Quarter Scale Beam Walker

NASA Astrophysics Data System (ADS)

Chun, Wendell H.; Price, R. S.; Spiessbach, Andrew J.

1990-03-01

Frame walkers are a class of mobile robots that are robust and capable mobility platforms. Variations of the frame walker robot are in commercial use today. Komatsu Ltd. of Japan developed the Remotely Controlled Underwater Surveyor (ReCUS) and Normed Shipyards of France developed the Marine Robot (RM3). Both applications of the frame walker concept satisfied robotic mobility requirements that could not be met by a wheeled or tracked design. One vehicle design concept that falls within this class of mobile robots is the walking beam. A one-quarter scale prototype of the walking beam was built by Martin Marietta to evaluate the potential merits of utilizing the vehicle as a planetary rover. The initial phase of prototype rover testing was structured to evaluate the mobility performance aspects of the vehicle. Performance parameters such as vehicle power, speed, and attitude control were evaluated as a function of the environment in which the prototype vehicle was tested. Subsequent testing phases will address the integrated performance of the vehicle and a local navigation system.

[Effect of abducens orthosis combined with walker on developmental dysplasia of the hip].

PubMed

Hu, Zhiyong; Xu, Yongqiang; Liang, Jieyu; Li, Kanghua; Liao, Qiande

2009-07-01

To evaluate the effect of abducens orthosis combined with walker on developmental dysplasia of the hip (DDH). A total of 126 patients (224 hips) with DDH aged 6-36 months in Xiangya Hospital was randomly divided into 2 groups: an orthosis combined with walker group and an improved hip frog cast fixation group. Seventy patients (130 hips) were treated by the orthosis combined with walker and 56 patients (94 hips) were treated by the improved hip frog cast fixation. We compared the effect and complications of the 2 groups. The fineness rates of the orthosis combined with walker group and the improved hip frog cast fixation group were 89.2% and 90.4%, respectively, with no significant difference (P>0.05). The rate of femoral head osteonecrosis in the orthosis combined with walker group was significantly lower than that in the improved hip frog cast fixation group (1.5% vs. 5.3%,P<0.05), but the re-dislocation rate in the former was significantly higher than that in the latter (6.9% vs. 1.1 %, P<0.05). Both methods are effective for DDH. Orthosis combined with walker has a lower proportion of femoral head osteonecrosis, but a higher proportion of re-dislocation.

CommWalker: correctly evaluating modules in molecular networks in light of annotation bias.

PubMed

Luecken, M D; Page, M J T; Crosby, A J; Mason, S; Reinert, G; Deane, C M

2018-03-15

Detecting novel functional modules in molecular networks is an important step in biological research. In the absence of gold standard functional modules, functional annotations are often used to verify whether detected modules/communities have biological meaning. However, as we show, the uneven distribution of functional annotations means that such evaluation methods favor communities of well-studied proteins. We propose a novel framework for the evaluation of communities as functional modules. Our proposed framework, CommWalker, takes communities as inputs and evaluates them in their local network environment by performing short random walks. We test CommWalker's ability to overcome annotation bias using input communities from four community detection methods on two protein interaction networks. We find that modules accepted by CommWalker are similarly co-expressed as those accepted by current methods. Crucially, CommWalker performs well not only in well-annotated regions, but also in regions otherwise obscured by poor annotation. CommWalker community prioritization both faithfully captures well-validated communities and identifies functional modules that may correspond to more novel biology. The CommWalker algorithm is freely available at opig.stats.ox.ac.uk/resources or as a docker image on the Docker Hub at hub.docker.com/r/lueckenmd/commwalker/. deane@stats.ox.ac.uk. Supplementary data are available at Bioinformatics online.

Vertical force and wrist deviation angle when using a walker to stand up and sit down.

PubMed

Leung, Cherng-Yee; Yeh, Po-Chan

2011-08-01

Research investigating walkers suggests that safety and assistance for the elderly with weak lower limbs were important. However, the relationship between the use of a walker and the upper limbs has received little investigation. Standing up and sitting down are important daily activities. Therefore, the aim of this study was to explore wrist deviation and vertical force among elderly individuals using a walker for assistance to stand up and sit down. In total, 64 elderly volunteers (M age = 80.22, SD = 9.36) were enrolled. Data were obtained from four load cells and a twin-axis wrist goniometer. Wrist deviation and vertical force were examined when participants used a walker with horizontal handles to assist in standing up and sitting down. Significant wrist angle deviation occurred with the use of a walker, with dorsiflexion of the right hand greater than that of the left. Males exerted significantly greater vertical force. In the sitting position, greater ulnar deviation was seen among experienced walker users, whereas during standing, experienced users exhibited greater dorsiflexion. The horizontal handles of most marketed walkers may cause user wrist deviations, suggesting researchers should pursue improvements in walker design.

STS-69 Mission Commander David M. Walker arrives at SLF

NASA Technical Reports Server (NTRS)

1995-01-01

STS-69 Mission Commander David M. Walker arrives at KSC's Shuttle Landing Facility. Walker and four fellow crew members flew in from Johnson Space Center, Houston in the T-38 jet aircraft traditionally used by the astronaut corps. Later today, the countdown will begin as final preparations continue toward liftoff of the Space Shuttle Endeavour at 11:04 a.m. EDT, August 31 on STS-69.

Comparison of upper extremity glenohumeral joint forces in children with cerebral palsy using anterior and posterior walkers - biomed 2009.

PubMed

Strifling, Kelly M B; Konop, Katherine A; Wang, Mei; Harris, Gerald F

2009-01-01

Walkers are prescribed with the notion that one type of walker will be better for a child than another. One underlying justification for this practice is the theory that one walker may produce less stress on the upper extremities as the patient uses the walker. Nevertheless, upper extremity joint loading is not typically analyzed during walker assisted gait in children with spastic diplegic cerebral palsy. It has been difficult to evaluate the theory of walker prescription based on upper extremity stresses because loading on the upper extremities however has not been quantified until recently. In this study, weight bearing on the glenohumeral joints was analyzed in five children with spastic diplegic cerebral palsy using both anterior and posterior walkers fitted with 6-axis handle transducers. Though walkers' effects on the upper extremities proved to be similar between walker types, the differences between the walkers may have some clinical significance in the long run. In general, posterior walker use created larger glenohumeral joint forces. Though these differences are not statistically significant, over time and with repetitive loading they may be clinically significant.

Dataset reporting the perceiver identification rates of basic emotions expressed by male, female and ambiguous gendered walkers in full-light, point-light and synthetically modelled point-light walkers.

PubMed

Halovic, Shaun; Kroos, Christian

2017-12-01

This data set describes the experimental data collected and reported in the research article "Walking my way? Walker gender and display format confounds the perception of specific emotions" (Halovic and Kroos, in press) [1]. The data set represent perceiver identification rates for different emotions (happiness, sadness, anger, fear and neutral), as displayed by full-light, point-light and synthetic point-light walkers. The perceiver identification scores have been transformed into H t rates, which represent proportions/percentages of correct identifications above what would be expected by chance. This data set also provides H t rates separately for male, female and ambiguously gendered walkers.

Mean first-passage times of non-Markovian random walkers in confinement.

PubMed

Guérin, T; Levernier, N; Bénichou, O; Voituriez, R

2016-06-16

The first-passage time, defined as the time a random walker takes to reach a target point in a confining domain, is a key quantity in the theory of stochastic processes. Its importance comes from its crucial role in quantifying the efficiency of processes as varied as diffusion-limited reactions, target search processes or the spread of diseases. Most methods of determining the properties of first-passage time in confined domains have been limited to Markovian (memoryless) processes. However, as soon as the random walker interacts with its environment, memory effects cannot be neglected: that is, the future motion of the random walker does not depend only on its current position, but also on its past trajectory. Examples of non-Markovian dynamics include single-file diffusion in narrow channels, or the motion of a tracer particle either attached to a polymeric chain or diffusing in simple or complex fluids such as nematics, dense soft colloids or viscoelastic solutions. Here we introduce an analytical approach to calculate, in the limit of a large confining volume, the mean first-passage time of a Gaussian non-Markovian random walker to a target. The non-Markovian features of the dynamics are encompassed by determining the statistical properties of the fictitious trajectory that the random walker would follow after the first-passage event takes place, which are shown to govern the first-passage time kinetics. This analysis is applicable to a broad range of stochastic processes, which may be correlated at long times. Our theoretical predictions are confirmed by numerical simulations for several examples of non-Markovian processes, including the case of fractional Brownian motion in one and higher dimensions. These results reveal, on the basis of Gaussian processes, the importance of memory effects in first-passage statistics of non-Markovian random walkers in confinement.

Mean first-passage times of non-Markovian random walkers in confinement

NASA Astrophysics Data System (ADS)

Guérin, T.; Levernier, N.; Bénichou, O.; Voituriez, R.

2016-06-01

The first-passage time, defined as the time a random walker takes to reach a target point in a confining domain, is a key quantity in the theory of stochastic processes. Its importance comes from its crucial role in quantifying the efficiency of processes as varied as diffusion-limited reactions, target search processes or the spread of diseases. Most methods of determining the properties of first-passage time in confined domains have been limited to Markovian (memoryless) processes. However, as soon as the random walker interacts with its environment, memory effects cannot be neglected: that is, the future motion of the random walker does not depend only on its current position, but also on its past trajectory. Examples of non-Markovian dynamics include single-file diffusion in narrow channels, or the motion of a tracer particle either attached to a polymeric chain or diffusing in simple or complex fluids such as nematics, dense soft colloids or viscoelastic solutions. Here we introduce an analytical approach to calculate, in the limit of a large confining volume, the mean first-passage time of a Gaussian non-Markovian random walker to a target. The non-Markovian features of the dynamics are encompassed by determining the statistical properties of the fictitious trajectory that the random walker would follow after the first-passage event takes place, which are shown to govern the first-passage time kinetics. This analysis is applicable to a broad range of stochastic processes, which may be correlated at long times. Our theoretical predictions are confirmed by numerical simulations for several examples of non-Markovian processes, including the case of fractional Brownian motion in one and higher dimensions. These results reveal, on the basis of Gaussian processes, the importance of memory effects in first-passage statistics of non-Markovian random walkers in confinement.

Walking my way? Walker gender and display format Confounds the perception of specific emotions.

PubMed

Halovic, Shaun; Kroos, Christian

2018-02-01

Previous evidence has shown that males and females display different gait kinematics which may influence the perception of emotions displayed through the same walking gait. We therefore investigated the influence of walker gender on the perception of happiness, sadness, anger and fear displayed through walking movements. Full-light (FL), point-light (PL) and synthetically modelled point-light walkers (SW) of both genders were shown to perceivers over three experiments. Additionally, gender ambiguous synthetic walkers were shown to control for the influence of form, gender stereotypes and idiosyncratic gait movements on emotional gait perception. Each emotion was identified above chance level for both walker genders and in all display conditions though significantly less in PL and SW than in FL. The gender of the walker did not influence the pattern of identifications in FL walkers (Fear > Sad > Happy > Anger > Neutral), but did influence the identification patterns in PL (Female: [Happy = Sad = Fear = Anger] > Neutral; Male: Fear = Sad = [Happy > Anger] > Neutral) and SWs (Female: Happy = Sad = Anger = Fear = Neutral; Male: [Happy = Sad = Anger] > [Fear = Neutral]; Ambiguous: [[Happy = Sad = Anger] > Fear] = Neutral). The gender of the walker and format in which they are displayed influenced the perception of different basic emotions. The constructed SW stimuli also displayed happiness, sadness and anger with equivalent intensity in female, male and gender ambiguous walkers thus untangling the perception-expression entanglement that has plagued previous emotion perception research. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Factors Associated with Women's Antenatal Plans to Use a Baby Walker: A Cross Sectional Study

ERIC Educational Resources Information Center

Illingworth, Rachel; Kendrick, Denise; Collier, Jacqueline; Woods, Amanda; Wattse, Kim; Dewey, Michael; Chen, Chih-Mei

2006-01-01

Objective: The objective of these analyses was to explore maternal antenatal decisions about baby walker use, factors associated with these decisions and the relationship between antenatal plans to use a walker and postnatal walker use. Design: Cross sectional study. Setting: Mothers-to-be (n = 1174) participating in a cluster randomised…

Perioperative management of a patient with Dandy Walker malformation with tetralogy of Fallot undergoing total correction and fresh homologous pericardial pulmonary valve conduit implantation: Report of a rare case

PubMed Central

Datt, Vishnu; Tempe, D. K.; Lalwani, Parin; Aggarwal, Saket; Kumar, Pradeep; Diwakar, Anitha; Tomar, A. S.

2015-01-01

Perioperative management of a patient with Dandy–Walker malformation (DWM) with tetralogy of Fallot (TOF), patent ductus arteriosus, and pulmonary artery stenosis is a great challenge to the anesthesiologist. Anesthetic management in such patients can trigger tet spells that might rapidly increase intracranial pressure (ICP), conning and even death. The increase in ICP can precipitate tet spells and further brain hypoxia. To avoid an increase in ICP during TOF corrective surgery ventriculo-peritoneal (VP) shunt should be performed before cardiac surgery. We present the first case report of a 11-month-old male baby afflicted with DWM and TOF who underwent successful TOF total corrective surgery and fresh autologous pericardial pulmonary valve conduit implantation under cardiopulmonary bypass after 1 week of VP shunt insertion. PMID:26139758

Recent intensification of the Walker Circulation and the role of natural sea surface temperature variability

NASA Astrophysics Data System (ADS)

Zhao, X.; Allen, R.

2017-12-01

In a warming world, the tropical atmospheric overturning circulation-including the Walker Circulation-is expected to weaken due to thermodynamic constraints. Tropical precipitation increases at a slower rate than water vapor-which increases according to Clausius Clapeyron scaling, assuming constant relative humidity-so the tropical overturning circulation slows down. This is supported by both observations and model simulations, which show a slowdown of the Walker Circulation over the 20th century. Model projections suggest a further weakening of the Walker Circulation in the 21st century. However, over the last several decades (1979-2014), multiple observations reveal a robust strengthening of the Walker Circulation. Although coupled CMIP5 simulations are unable to reproduce this strengthening, AMIP simulations-which feature the observed evolution of SSTs-are generally able to reproduce it. Assuming the ensemble mean sea surface temperatures (SSTs) from historical CMIP5 simulations accurately represent the externally forced SST response, the observed SSTs can be decomposed into a forced and an unforced component. CAM5 AMIP-type simulations driven by the unforced component of observed SSTs reproduce the observed strengthening of the Walker Circulation. Corresponding simulations driven by the forced component of observed SSTs yield a weaker Walker Circulation. These results are consistent with the zonal tropical SST gradient and the Bjerknes feedback. The unforced component of SSTs yield an increased SST gradient over tropical Pacific (a La Nina like pattern) and strengthening of the tropical trade winds, which constitute the lower branch of the Walker Circulation. The forced component of SSTs yields a zonally uniform tropical Pacific SST warming and a marginal weakening of the Walker Circulation. Our results suggest significant modulation of the tropical Walker Circulation by natural SST variability over the last several decades.

Anterior or posterior walkers for children with cerebral palsy? A systematic review.

PubMed

Poole, Marilyn; Simkiss, Doug; Rose, Alice; Li, François-Xavier

2018-05-01

To review the literature comparing use of anterior and posterior walkers (PW's) by children with cerebral palsy (CP) to determine which walker type is preferable. Electronic databases were searched using pre-defined terms by two independent reviewers. Reference lists of included studies were hand searched. Studies published between 1985 and 2016 comparing use of anterior and PW's by children with CP were included. All study designs and outcomes were accepted. Risk of bias was assessed using the "Quality assessment standard for a cross-over study". Quality of evidence was evaluated using GRADE. Six studies were analysed. All studies had small sample sizes. A total of 4/6 studies were randomized. A total of 4/6 had high risk of bias. Outcomes included velocity, pelvic tilt, hip flexion, knee flexion, step length, stride length, cadence, double stance time, oxygen cost and participant/parental preference. Velocity, trunk flexion/pelvic tilt, and stability may be improved by using a PW, however, GRADE quality was very low for all outcomes and there was heterogeneity between studies. The majority of participants and parents preferred the PW. Heterogeneity and low quality of existing evidence prevented recommendation of one walker type. Well-designed studies with adequate power are needed to inform clinical recommendations. Implications for rehabilitation Clinical recommendations cannot be made for whether anterior or posterior walkers are preferable for children with cerebral palsy based on the existing evidence. Velocity, trunk flexion/pelvic tilt, and stability may be improved by using a posterior walker. The majority of walking aid users and their parents preferred posterior walkers. Adequately powered studies designed to minimize bias are needed.

Change in the size of Walker Lake during the past 5000 years

USGS Publications Warehouse

Benson, L.V.; Meyers, P.A.; Spencer, R.J.

1991-01-01

In 1984, a 12-m sediment core (WLC84-8) was taken from the deepest part of Walker Lake. Samples of the core were analysed for diatoms, pollen, carbonate mineralogy, magnesium content, ??18O and ??13C values of the total inorganic fractin, ??18O and ??13C values of Limnocythere ceriotuberosa, ??13C values of the total organic fraction, grain size, and magnetic susceptibility. The data indicate that Walker Lake became shallow and probably desiccated between ???5300-4800 and 2700-2100 yr B.P.. Each of the organic and inorganic proxy indicators of lake size discussed in this paper was useful in determining the presence of the shallow-lake intervals. However, none of the indicators was useful in determining the cause of the shallow-lake intervals. Instead, the types of fish living in Walker Lake prior to 1940 were used to demonstrate that shallow-lake intervals resulted from diversion of the Walker River and not from climatic aridity. Major changes in mineralogy and magnesium content of carbonates and major changes in diatom populations with time were found to be a function of the chemical evolution of Walker Lake combined with changing lake size. The stable isotopes of oxygen and carbon were found to be good indicators of lake volume changes. A lake-level record for Walker Lake constructed from stable-isotope data was found to be similar to a lake-level record constructed using tufa and tree-stump data. Both records indicate relatively high lake levels between 4800-2700 yr B.P., at 1250 yr B.P., and within the last 300 yr. Substantial declines in lake level occurred ???2000 and ???1000 yr B.P. ?? 1991.

The fire-walker's high: affect and physiological responses in an extreme collective ritual.

PubMed

Fischer, Ronald; Xygalatas, Dimitris; Mitkidis, Panagiotis; Reddish, Paul; Tok, Penny; Konvalinka, Ivana; Bulbulia, Joseph

2014-01-01

How do people feel during extreme collective rituals? Despite longstanding speculation, few studies have attempted to quantify ritual experiences. Using a novel pre/post design, we quantified physiological fluctuations (heart rates) and self-reported affective states from a collective fire-walking ritual in a Mauritian Hindu community. Specifically, we compared changes in levels of happiness, fatigue, and heart rate reactivity among high-ordeal participants (fire-walkers), low-ordeal participants (non-fire-walking participants with familial bonds to fire-walkers) and spectators (unrelated/unknown to the fire-walkers). We observed that fire-walkers experienced the highest increase in heart rate and reported greater happiness post-ritual compared to low-ordeal participants and spectators. Low-ordeal participants reported increased fatigue after the ritual compared to both fire-walkers and spectators, suggesting empathetic identification effects. Thus, witnessing the ritualistic suffering of loved ones may be more exhausting than experiencing suffering oneself. The findings demonstrate that the level of ritual involvement is important for shaping affective responses to collective rituals. Enduring a ritual ordeal is associated with greater happiness, whereas observing a loved-one endure a ritual ordeal is associated with greater fatigue post-ritual.

Compliant walker

NASA Technical Reports Server (NTRS)

Kerley, James J. (Inventor); Eklund, Wayne D. (Inventor); Crane, J. Allen (Inventor)

1992-01-01

A compliant walker is provided for humans having limited use of their legs and lower back. It includes an upright wheel frame which at least partially surrounds an upright user wearing a partial body harness. It is attached to the frame by means of cable compliant apparatus consisting of sets of cable segments and angle bracket members connected between opposite side members of the frame and adjacent side portions of the harness. Novelty is believed to exist in the combination of a wheeled frame including a side support structure, a body harness, and compliance means connecting the body harness to the side support structure for flexibility holding and supporting a person in a substantially upright position when the user sags in the frame when taking weight off the lower extremities.

HitWalker2: visual analytics for precision medicine and beyond.

PubMed

Bottomly, Daniel; McWeeney, Shannon K; Wilmot, Beth

2016-04-15

The lack of visualization frameworks to guide interpretation and facilitate discovery is a potential bottleneck for precision medicine, systems genetics and other studies. To address this we have developed an interactive, reproducible, web-based prioritization approach that builds on our earlier work. HitWalker2 is highly flexible and can utilize many data types and prioritization methods based upon available data and desired questions, allowing it to be utilized in a diverse range of studies such as cancer, infectious disease and psychiatric disorders. Source code is freely available at https://github.com/biodev/HitWalker2 and implemented using Python/Django, Neo4j and Javascript (D3.js and jQuery). We support major open source browsers (e.g. Firefox and Chromium/Chrome). wilmotb@ohsu.edu Supplementary data are available at Bioinformatics online. Additional information/instructions are available at https://github.com/biodev/HitWalker2/wiki. © The Author 2015. Published by Oxford University Press.

[Upper extremity kinetics and energy expenditure during walker-assisted gait in children with cerebral palsy].

PubMed

Konop, Katherine A; Strifling, Kelly M B; Wang, Mei; Cao, Kevin; Eastwood, Daniel; Jackson, Scott; Ackman, Jeffrey; Altiok, Haluk; Schwab, Jeffrey; Harris, Gerald F

2009-01-01

We evaluated the relationships between upper extremity (UE) kinetics and the energy expenditure index during anterior and posterior walker-assisted gait in children with spastic diplegic cerebral palsy (CP). Ten children (3 boys, 7 girls; mean age 12.1 years; range 8 to 18 years) with spastic diplegic CP, who ambulated with a walker underwent gait analyses that included UE kinematics and kinetics. Upper extremity kinetics were obtained using instrumented walker handles. Energy expenditure index was obtained using the heart rate method (EEIHR) by subtracting resting heart rate from walking heart rate, and dividing by the walking speed. Correlations were sought between the kinetic variables and the EEIHR and temporal and stride parameters. In general, anterior walker use was associated with a higher EEIHR. Several kinetic variables correlated well with temporal and stride parameters, as well as the EEIHR. All of the significant correlations (r>0.80; p<0.005) occurred during anterior walker use and involved joint reaction forces (JRF) rather than moments. Some variables showed multiple strong correlations during anterior walker use, including the medial JRF in the wrist, the posterior JRF in the elbow, and the inferior and superior JRFs in the shoulder. The observed correlations may indicate a relationship between the force used to advance the body forward within the walker frame and an increased EEIHR. More work is needed to refine the correlations, and to explore relationships with other variables, including the joint kinematics.

[Needs, uses, cons-pros, good practices and opportunities about walker in elderly with loss of autonomy].

PubMed

Mézière, Anthony; Schonheit, Claire; Moreau, Caroline; Baudry, Elodie; Monié, Marguerite; Piette, François; Curtis, Valentine; Pasqui, Viviane

2015-01-01

Non-use of the walker may be secondary to an initial inappropriate prescribing, a lack of adequate training, a lack of monitoring and side effects of using. Improving both stability and mobility in users is due to several biomechanical mechanisms. The benefits of walker are: general physiological effects, more confidence, better social life and decrease in the burden of care. The disadvantages of walker are: technical or practical aspects criticized by users, musculoskeletal disorders, delayed reaction time, fall risk and stigma. Few scientific data evaluating the interest of the walker concerning mobility exist, thus recommendations are low grade and are often taken from professional clinical experiences. The choice of technical walking assistance depends on the pathology and biomechanical mechanism. The walker robots are few distributed. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Effect of uphill and downhill walking on walking performance in geriatric patients using a wheeled walker.

PubMed

Lindemann, Ulrich; Schwenk, Michael; Schmitt, Syn; Weyrich, Michael; Schlicht, Wolfgang; Becker, Clemens

2017-08-01

Wheeled walkers are recommended to improve walking performance in older persons and to encourage and assist participation in daily life. Nevertheless, using a wheeled walker can cause serious problems in the natural environment. This study aimed to compare uphill and downhill walking with walking level in geriatric patients using a wheeled walker. Furthermore, we investigated the effect of using a wheeled walker with respect to dual tasking when walking level. A total of 20 geriatric patients (median age 84.5 years) walked 10 m at their habitual pace along a level surface, uphill and downhill, with and without a standard wheeled walker. Gait speed, stride length and cadence were assessed by wearable sensors and the walk ratio was calculated. When using a wheeled walker while walking level the walk ratio improved (0.58 m/[steps/min] versus 0.57 m/[steps/min], p = 0.023) but gait speed decreased (1.07 m/s versus 1.12 m/s, p = 0.020) when compared to not using a wheeled walker. With respect to the walk ratio, uphill and downhill walking with a wheeled walker decreased walking performance when compared to level walking (0.54 m/[steps/min] versus 0.58 m/[steps/min], p = 0.023 and 0.55 m/[steps/min] versus 0.58 m/[steps/min], p = 0.001, respectively). At the same time, gait speed decreased (0.079 m/s versus 1.07 m/s, p < 0.0001) or was unaffected. The use of a wheeled walker improved the quality of level walking but the performance of uphill and downhill walking was worse compared to walking level when using a wheeled walker.

STS-53 Commander Walker adjusts LES prior to JSC emergency egress training

NASA Technical Reports Server (NTRS)

1992-01-01

STS-53 Discovery, Orbiter Vehicle (OV) 103, Commander David M. Walker pulls at launch and entry suit (LES) neck ring and neck dam in an attempt to adjust it and/or loosen it. Walker appears uncomfortable and makes the adjustments in preparation for launch emergency egress bailout procedures in JSC's Mockup and Integration Laboratory (MAIL) Bldg 9NE.

Active transtensional intracontinental basins: Walker Lane in the western Great Basin

USGS Publications Warehouse

Jayko, Angela S.; Bursik, Marcus

2012-01-01

The geometry and dimensions of sedimentary basins within the Walker Lane are a result of Plio-Pleistocene transtensive deformation and partial detachment of the Sierra Nevada crustal block from the North American plate. Distinct morpho-tectonic domains lie within this active transtensive zone. The northeast end of the Walker Lane is partly buried by active volcanism of the southern Cascades, and adjacent basins are filled or poorly developed. To the south, the basin sizes are moderate, 25–45km × 15–10 km, with narrow 8-12km wide mountain ranges mainly oriented N-S to NNE. These basins form subparallel arrays in discrete zones trending about 300° and have documented clockwise rotation. This is succeeded to the south by a releasing stepover domain ∼85-100km wide, where the basins are elongated E-W to ENE, small (∼15-30km long, 5-15km wide), and locally occupied by active volcanic centers. The southernmost part of the Walker Lane is structurally integrated, with high to extreme relief. Adjacent basins are elongate, 50-200km long and ∼5 -20km wide. Variations in transtensive basin orientations in the Walker Lane are largely attributable to variations in strain partitioning. Large basins in the Walker Lane have 2-6km displacement across basin bounding faults with up to 3 km of clastic accumulation based on gravity and drill hole data. The sedimentary deposits of the basins may include interbedded volcanic deposits with bimodal basaltic and rhyolitic associations. The basins may include lacustrine deposits that record a wide range of water chemistry from cold fresh water conditions to saline-evaporative

Influence of an infant walker on onset and quality of walking pattern of locomotion:an electromyographic investigation.

PubMed

Kauffman, I B; Ridenour, M

1977-12-01

Acquisition of bipedal locomotor skill in human infants was studied electromyographically with regard to the deprivation or enrichment behavior resulting from the frequent and regular use of an infant walker. Subjects were six sets of male, fraternal twins. One randomly selected sibling from each set underwent a training program, commencing at the age of 300 days, spending a total of 2 hr. per day in a walker. Siblings not included in this group were subjected to no special training. EMG recordings were taken of all subjects at specified intervals in order to establish a model of the typical motor pattern at various stages of skill development. These data were then contrasted with EMG data similarly obtained from the walker-trained subjects. Use of an infant walker modified the mechanics of the infant's locomotion in a number of important ways. It was shown that use of the walker enables an infant to commit substantial mechanical errors yet succeed in bipedal locomotion. Inasmuch as the mechanics of walker-assisted and non-assisted bipedal locomotion are dissimilar in so many important ways, positive transfer from walker-training appears questionable.

Directional transport of colloids inside a bath of self-propelling walkers.

PubMed

Merlitz, Holger; Wu, Chenxu; Sommer, Jens-Uwe

2017-05-24

We present a setup in which passive colloids inside a solvent are moved to the boundaries of the container. The directional transport is facilitated by self-propelling microparticles ("walkers") with an activity gradient, which reduces their propulsion in the vicinity of bounding walls. An attractive interaction leads to the adsorption of walkers onto the colloid-surfaces in regions of low walker activity. It is shown that the activity gradient generates a free energy gradient which in turn acts as a driving force on the passive colloids. We carry out molecular dynamics simulations and present approaches to a theoretical description of the involved processes. Although the simulation data are not reproduced on a fully quantitative level, their qualitative features are covered by the model. The effect described here may be applied to facilitate a directional transport of drugs or to eliminate pollutants.

76 FR 13665 - Arcelor Mittal, Formerly Known as Mittal Steel Walker Wire, a Subsidiary of Arcelor Mittal...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-14

... Known as Mittal Steel Walker Wire, a Subsidiary of Arcelor Mittal--Montreal, Including On-Site Leased... Steel Walker Wire, a subsidiary of Arcelor Mittal-- Montreal, including on-site leased workers from... Walker Wire, Inc., Ferndale, Michigan, separated from employment on or after July 23, 2006 through August...

A modified Fermi-Walker derivative for inextensible flows of binormal spherical image

NASA Astrophysics Data System (ADS)

Suroğlu, Gülden Altay

2018-03-01

Fermi-Walker derivative and biharmonic particle play an important role in skillful applications. We obtain a new characterization on binormal spherical indicatrix by using the Fermi-Walker derivative and parallelism in space. We suggest that an inextensible flow is the necessary and sufficient condition for this particle. Finally, we give some characterizations for a non-rotating frame of this binormal spherical indicatrix.

10. Photocopy of photograph showing the three Walker sisters ginning ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Photocopy of photograph showing the three Walker sisters ginning cotton. Misses Hettie, Martha and Louisa are from left to right. The original photograph was taken on May 21, 1936 by Edouard E. Exline and is one of five photographs in the album, 'A Sketch of Mountain Life: Great Smoky Mountains National Park', compiled by Edouard E. Exline and C.S. Grossman. The album is on file at the Great Smoky Mountains National Park; the photograph number is III-A-HSE-9642. - Walker Family Farm (General views), Gatlinburg, Sevier County, TN

Gender Recognition from Point-Light Walkers

ERIC Educational Resources Information Center

Pollick, Frank E.; Kay, Jim W.; Heim, Katrin; Stringer, Rebecca

2005-01-01

Point-light displays of human gait provide information sufficient to recognize the gender of a walker and are taken as evidence of the exquisite tuning of the visual system to biological motion. The authors revisit this topic with the goals of quantifying human efficiency at gender recognition. To achieve this, the authors first derive an ideal…

Joseph A. Walker after X-15 flight #2-14-28

NASA Image and Video Library

1961-03-30

Joseph A. Walker was a Chief Research Pilot at the NASA Dryden Flight Research Center during the mid-1960s. He joined the NACA in March 1945, and served as project pilot at the Edwards flight research facility on such pioneering research projects as the D-558-1, D-558-2, X-1, X-3, X-4, X-5, and the X-15. He also flew programs involving the F-100, F-101, F-102, F-104, and the B-47. Walker made the first NASA X-15 flight on March 25, 1960. He flew the research aircraft 24 times and achieved its fastest speed and highest altitude. He attained a speed of 4,104 mph (Mach 5.92) during a flight on June 27, 1962, and reached an altitude of 354,300 feet on August 22, 1963 (his last X-15 flight). He was the first man to pilot the Lunar Landing Research Vehicle (LLRV) that was used to develop piloting and operational techniques for lunar landings. Walker was born February 20, 1921, in Washington, Pa. He lived there until graduating from Washington and Jefferson College in 1942, with a B.A. degree in Physics. During World War II he flew P-38 fighters for the Air Force, earning the Distinguished Flying Cross and the Air Medal with Seven Oak Clusters. Walker was the recipient of many awards during his 21 years as a research pilot. These include the 1961 Robert J. Collier Trophy, 1961 Harmon International Trophy for Aviators, the 1961 Kincheloe Award and 1961 Octave Chanute Award. He received an honorary Doctor of Aeronautical Sciences degree from his alma mater in June of 1962. Walker was named Pilot of the Year in 1963 by the National Pilots Association. He was a charter member of the Society of Experimental Test Pilots, and one of the first to be designated a Fellow. He was fatally injured on June 8, 1966, in a mid-air collision between an F-104 he was piloting and the XB-70.

Measuring cortical motor hemodynamics during assisted stepping - An fNIRS feasibility study of using a walker.

PubMed

de Lima-Pardini, Andrea Cristina; Zimeo Morais, Guilherme A; Balardin, Joana Bisol; Coelho, Daniel Boari; Azzi, Nametala Maia; Teixeira, Luis Augusto; Sato, João Ricardo

2017-07-01

Walkers are commonly prescribed worldwide to individuals unable to walk independently. Walker usage leads to improved postural control and voluntary movement during step. In the present study, we aimed to provide a concept-proof on the feasibility of an event-related protocol integrating the analyses of biomechanical variables of step initiation and functional near-infrared spectroscopy (fNIRS) to measure activation of the supplementary motor area (SMA) while using a walker. Healthy young participants were tested while stepping with versus without the use of the walker. Behavioral analysis showed that anticipatory postural adjustments (APA) decreased when supporting the body weight on the walker. Delta (without-with) of activation magnitude of the muscle tibialis anterior was positively correlated to the delta of deoxyhemoglobin concentration changes in the SMA. The novelty of this study is the development of a protocol to assess brain function together with biomechanical analysis during the use of a walker. The method sheds light to the potential utility of combining fNIRS and biomechanical assessment during assistive step initiation, which can represent a new opportunity to study populations with mobility deficits. Copyright © 2017 Elsevier B.V. All rights reserved.

A New Controller for a Smart Walker Based on Human-Robot Formation

PubMed Central

Valadão, Carlos; Caldeira, Eliete; Bastos-Filho, Teodiano; Frizera-Neto, Anselmo; Carelli, Ricardo

2016-01-01

This paper presents the development of a smart walker that uses a formation controller in its displacements. Encoders, a laser range finder and ultrasound are the sensors used in the walker. The control actions are based on the user (human) location, who is the actual formation leader. There is neither a sensor attached to the user’s body nor force sensors attached to the arm supports of the walker, and thus, the control algorithm projects the measurements taken from the laser sensor into the user reference and, then, calculates the linear and angular walker’s velocity to keep the formation (distance and angle) in relation to the user. An algorithm was developed to detect the user’s legs, whose distances from the laser sensor provide the information necessary to the controller. The controller was theoretically analyzed regarding its stability, simulated and validated with real users, showing accurate performance in all experiments. In addition, safety rules are used to check both the user and the device conditions, in order to guarantee that the user will not have any risks when using the smart walker. The applicability of this device is for helping people with lower limb mobility impairments. PMID:27447634

Quantum Tunneling and Chaos in Classical Scale Walkers

NASA Astrophysics Data System (ADS)

Su, Jenny; Dijksman, Joshua; Ward, Jeremy; Behringer, Robert

2014-03-01

We study the behavior of `walkers' small droplets bouncing on a fluid layer vibrated at amplitudes just below the onset of Faraday instability. It was shown recently that despite their macroscopic size, the droplet dynamics are stochastic in nature and reminiscent of the dual particle-wave dynamics in the realm of quantum mechanics (Couder PRL 2006). We use these walkers to study how chaos, which is macroscopically unpredictable, will manifest in a quantum setting. Pecora showed in 2011 that tunneling for particles that have a chaotic ground state is different from tunneling for particles with a regular ground state (PRE 2011). In the experiment we gather data that illustrates the particle trajectory and tunneling behavior as particles transition across the barrier in the double well system with both integrable and chaotic shapes.

Coarctation of the aorta associated with Dandy–Walker variant

PubMed Central

Zhou, Li; Lui, George K.; Shenoy, Rajesh; Taub, Cynthia C.

2013-01-01

This article reports a rare case of coarctation of the aorta associated with Dandy–Walker variant in a 17-year-old girl. Differential diagnoses of coarctation of the aorta and Dandy–Walker variant are extensively discussed. In addition, standard surgical treatment of coarctation as well as new approaches such as endovascular stenting are described in detail to provide therapeutic insights into her management. Although surgical or endovascular repair of coarctation results in significant improvement of systemic hypertension and is associated with better survival, cardiovascular complications are still very common. Thus, long-term follow-up after repair is required, and high-quality imaging studies such as echocardiography, CT and MRI are warranted. PMID:24396258

Walker River Paiutes: A Tribal History.

ERIC Educational Resources Information Center

Johnson, Edward C.

The Northern Paiute people of Nevada's Walker Lake area were known as the Agai Diccutta (Trout Eaters); they called themselves the Numa, or the People. For as long as anyone could recall, they had lived in the area, catching the huge trout from the lake and harvesting the pinon nuts and other foods from the surrounding desert. In the 1820's the…

Binding-induced DNA walker for signal amplification in highly selective electrochemical detection of protein.

PubMed

Ji, Yuhang; Zhang, Lei; Zhu, Longyi; Lei, Jianping; Wu, Jie; Ju, Huangxian

2017-10-15

A binding-induced DNA walker-assisted signal amplification was developed for highly selective electrochemical detection of protein. Firstly, the track of DNA walker was constructed by self-assembly of the high density ferrocene (Fc)-labeled anchor DNA and aptamer 1 on the gold electrode surface. Sequentially, a long swing-arm chain containing aptamer 2 and walking strand DNA was introduced onto gold electrode through aptamers-target specific recognition, and thus initiated walker strand sequences to hybridize with anchor DNA. Then, the DNA walker was activated by the stepwise cleavage of the hybridized anchor DNA by nicking endonuclease to release multiple Fc molecules for signal amplification. Taking thrombin as the model target, the Fc-generated electrochemical signal decreased linearly with logarithm value of thrombin concentration ranging from 10pM to 100nM with a detection limit of 2.5pM under the optimal conditions. By integrating the specific recognition of aptamers to target with the enzymatic cleavage of nicking endonuclease, the aptasensor showed the high selectivity. The binding-induced DNA walker provides a promising strategy for signal amplification in electrochemical biosensor, and has the extensive applications in sensitive and selective detection of the various targets. Copyright © 2017 Elsevier B.V. All rights reserved.

A biomechanical analysis of upper extremity kinetics in children with cerebral palsy using anterior and posterior walkers.

PubMed

Konop, Katherine A; Strifling, Kelly M B; Wang, Mei; Cao, Kevin; Schwab, Jeffrey P; Eastwood, Daniel; Jackson, Scott; Ackman, Jeffrey D; Harris, Gerald F

2009-10-01

Upper extremity (UE) joint kinetics during aided ambulation is an area of research that is not well characterized in the current literature. Biped UE joints are not anatomically designed to be weight bearing, therefore it is important to quantify UE kinetics during assisted gait. This will help to better understand the biomechanical implications of UE weight bearing, and enable physicians to prescribe more effective methods for treatment and therapy, perhaps minimizing excessive loads and torques. To address this challenge, an UE model that incorporates both kinematics and kinetics has been developed for use with walkers instrumented with load cells. In this study, the UE joint kinetics are calculated for 10 children with cerebral palsy using both anterior and posterior walkers. Three-dimensional joint reaction forces and moments are fully characterized for the wrist, elbow, and shoulder (glenohumeral) joints for both walker types. Statistical analysis methods are used to quantify the differences in forces or moments between the two walker types. Comparisons showed no significant differences in kinetic joint parameters between walker types. Results from a power analysis of the current data are provided which may be useful for planning longer term clinical studies. If risk factors for UE joint pathology can be identified early, perhaps a change in gait training routine, walker prescription, or walker design could prevent further harm.

Hydrologic data for the Walker River Basin, Nevada and California, water years 2010–14

USGS Publications Warehouse

Pavelko, Michael T.; Orozco, Erin L.

2015-12-10

Walker Lake is a threatened and federally protected desert terminal lake in western Nevada. To help protect the desert terminal lake and the surrounding watershed, the Bureau of Reclamation and U.S. Geological Survey have been studying the hydrology of the Walker River Basin in Nevada and California since 2004. Hydrologic data collected for this study during water years 2010 through 2014 included groundwater levels, surface-water discharge, water chemistry, and meteorological data. Groundwater levels were measured in wells, and surface-water discharge was measured in streams, canals, and ditches. Water samples for chemical analyses were collected from wells, streams, springs, and Walker Lake. Chemical analyses included determining physical properties; the concentrations of major ions, nutrients, trace metals, dissolved gases, and radionuclides; and ratios of the stable isotopes of hydrogen and oxygen. Walker Lake water properties and meteorological parameters were monitored from a floating platform on the lake. Data collection methods followed established U.S. Geological Survey guidelines, and all data are stored in the National Water Information System database. All of the data are presented in this report and accessible on the internet, except multiple-depth Walker Lake water-chemistry data, which are available only in this report.

Changes of neurotransmitters in the brainstem of patients with respiratory-pattern disorders during childhood.

PubMed

Saito, Y; Ito, M; Ozawa, Y; Obonai, T; Kobayashi, Y; Washizawa, K; Ohsone, Y; Takami, T; Oku, K; Takashima, S

1999-06-01

We examined neuropathologically and immunohistochemically the respiratory centers in the brainstem of two patients with Joubert syndrome (JS), three patients with congenital central hypoventilation syndrome (CCHS) and a patient with apneustic breathing (prolonged inspiratory pause) due to unknown etiology. Immunoreactivity (IR) of tryptophan hydroxylase (TPH) was decreased in the dorsal raphe nuclei of two patients with JS compared with age-matched controls, as well as in two patients with Dandy-Walker malformation. The two JS patients showed vermian defect and elongated cerebellar peduncles, and peculiar vascularities in the midline of the whole brainstem were also noted in one of these patients. These findings, as a whole, confirm that the midline structures of brainstem are disordered both structurally and functionally in JS, conceivably resulting in respiratory patterns and psychomotor deficits. IR of serotonin 1A receptor showed no significant changes in the medulla oblongata of these patients, however. In the parabrachial complex, IR of substance P was increased in two patients with CCHS, and one with apneustic breathing. IR of tyrosine hydroxylase was also increased in the latter. The brainstem of these patients showed reactive astrogliosis. These findings suggest preceding hypoxic episodes as well as an increased activity in the parabrachial complex which plays an important role in conducting the driving force to the medullary respiratory neurons from ascending sensory pathways.

Test pilots 1962 - Armstrong, Walker, Dana, Peterson, McKay, Thompson, Butchart

NASA Technical Reports Server (NTRS)

1962-01-01

The research pilots at what in 1962 was called the Flight Research Center standing in front of the X-1E. They are (left to right) Neil Armstrong, Joe Walker, Bill Dana, Bruce Peterson, Jack McKay, Milt Thompson, and Stan Butchart. of the group, Armstrong, Walker, Dana, McKay and Thompson all flew the X-15. Bruce Peterson flew the M2-F2 and HL-10 lifting bodies, while Stan Butchart was the B-29 drop plane pilot for many of the D-558-II and X-1 series research aircraft.

Walker and Wheelock in MRM-1

NASA Image and Video Library

2010-11-19

ISS025-E-017111 (22 Nov. 2010)--- NASA astronauts Shannon Walker, Expedition 25 flight engineer, and Doug Wheelock, Expedition 25 commander; have donned their Sokol (Russian word for 'Falcon') pressure suits and are pictured in the Russian MRM-1 module aboard the Earth-orbiting International Space Station. They, along with Russian cosmonaut Fyodor Yurchikhin, flight engineer, ingressed the docked Soyuz capsule to conduct pressurization and leak checks on their suits.

Race walking gait and its influence on race walking economy in world-class race walkers.

PubMed

Gomez-Ezeiza, Josu; Torres-Unda, Jon; Tam, Nicholas; Irazusta, Jon; Granados, Cristina; Santos-Concejero, Jordan

2018-03-06

The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers. Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km·h -1 , where race walking economy (ml·kg -1 ·km -1 ) and spatiotemporal gait variables were analysed at different speeds. 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p < 0.001). Longer ground contact times, shorter flight times, longer midstance sub-phase and shorter propulsive sub-phase during stance were related to a better race walking economy (moderate effect, p < 0.05). According to the results of this study, the fastest race walkers were more economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification.

Cerebellar Development and Disease

PubMed Central

Gleeson, Joseph G.

2008-01-01

Recent Advances The molecular control of cell type specification within the developing cerebellum as well as the genetic causes of the most common human developmental cerebellar disorders have long remained mysterious. Recent genetic lineage and loss-of-function data from mice have revealed unique and non-overlapping anatomical origins for GABAergic neurons from ventricular zone precursors and glutamatergic cell from rhombic lip precursors, mirroring distinct origins for these neurotransmitter-specific cell types in the cerebral cortex. Mouse studies elucidating the role of Ptf1a as a cerebellar ventricular zone GABerigic fate switch were actually preceded by the recognition that PTF1A mutations in humans cause cerebellar agenesis, a birth defect of the human cerebellum. Indeed, several genes for congenital human cerebellar malformations have recently been identified, including genes causing Joubert syndrome, Dandy-Walker malformation and Ponto-cerebellar hypoplasia. These studies have pointed to surprisingly complex roles for transcriptional regulation, mitochondrial function and neuronal cilia in patterning, homeostasis and cell proliferation during cerebellar development. Together mouse and human studies are synergistically advancing our understanding of the developmental mechanisms that generate the uniquely complex mature cerebellum. PMID:18513948

Ring chromosome 10: report on two patients and review of the literature.

PubMed

Guilherme, Roberta Santos; Kim, Chong Ae; Alonso, Luis Garcia; Honjo, Rachel S; Meloni, Vera Ayres; Christofolini, Denise Maria; Kulikowski, Leslie Domenici; Melaragno, Maria Isabel

2013-02-01

Ring chromosome 10--r(10)--is a rare disorder, with 14 cases reported in the literature, but only two with breakpoint determination by high-resolution techniques. We report here on two patients presenting a ring chromosome 10, studied by G-banding, fluorescent in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA) and SNP-array techniques, in order to investigate ring instability and determine breakpoints. Patient 1 showed a r(10)(p15.3q26.2) with a 7.9 Mb deletion in 10q26.2-q26.2, while patient 2 showed a r(10)(p15.3q26.13) with a 1.0 Mb deletion in 10p15.3 and a 8.8 Mb deletion in 10q26.13-q26.3, both unstable. While patient 1 presented with clinical features usually found in patients with r(10) and terminal 10q deletion, patient 2 presented characteristics so far not described in other patients with r(10), such as Dandy-Walker variant, osteopenia, semi-flexed legs, and dermal pigmentation regions. Our data and the data from literature show that there are no specific clinical findings to define a r(10) syndrome.

A unique case of a discontinuous duplication 3q26.1-3q28 resulting from a segregation error of a maternal complex chromosomal rearrangement involving an insertion and an inversion.

PubMed

Rodríguez, Laura; Bhatt, Samarth S; García-Castro, Mónica; Plasencia, Ana; Fernández-Toral, Joaquín; Abarca, Elena; de Bello Cioffi, Marcelo; Liehr, Thomas

2014-02-10

Until now, few cases of partial trisomy of 3q due to segregation error of parental balanced translocation and segregation of a duplicated deficient product resulting from parental pericentric inversion have been reported so far. Only five cases of chromosomal insertion malsegregation involving 3q region are available yet, thus making it relatively rare. In this case report, we are presenting a unique case of discontinuous partial trisomy of 3q26.1-q28 region which resulted from a segregation error of two insertions involving 3q26.1 to 3q27.3 and 3q28 regions with ~21Mb and ~2Mb sizes, respectively. The maternally inherited insertion was cytogenetically characterized as der(8)(8pter→8p22::3q26→3q27.3::3q28→3q28::8p22→8qter) and the patient's major clinical features involved Dandy Walker malformation, sub-aortic ventricular septal defect, upslanting palpebral fissures, clinodactyly, hirsutism, and prominent forehead. Besides, a review of the literature involving cases with similar chromosomal imbalances and cases with "3q-duplication syndrome" is also provided. Copyright © 2013 Elsevier B.V. All rights reserved.

Pole walking down-under: profile of pole walking leaders, walkers and programs in Australia and factors relating to participation.

PubMed

Fritschi, Juliette O; van Uffelen, Jannique G Z; Brown, Wendy J

2014-12-01

Although pole walking (PW) has the potential to be a useful health-enhancing physical activity (PA), little is known about by whom or how it is being practised. The aims of this study were to describe (1) the characteristics of PW leaders, pole walkers and PW programs in Australia, and (2) participants' perceptions of PW and their reasons for participation. In 2012, PW leaders (n=31) and walkers (n=107) completed self-administered surveys that included questions about participants' sociodemographic and health characteristics, PW programs and perceptions of PW. Data were analysed using SPSS. Leaders and walkers were generally born in Australia (leaders, 71%; walkers, 83%), older (leaders, 55 years [s.d. 11.5]; walkers, 65 years [s.d. 10.6]) and female (leaders, 77%; walkers, 79%). Most walkers (82%) walked regularly in groups, approximately once per week for about an hour, at light to moderate intensity. The program's aims most strongly endorsed by PW leaders were to increase participant enjoyment (90%), increase PA levels (81%), provide a positive social experience (77%) and increase PA confidence (71%). The most strongly endorsed motivations for PW among walkers were to remain physically active (63%), improve fitness (62%) and personal and social enjoyment (60%). In Australia, PW is being practised by a health conscious, older population. It is perceived as an enjoyable and health-enhancing outdoor activity. SO WHAT?: Health and exercise practitioners may find that PW is a beneficial form of PA for older Australians.

Extraction of user's navigation commands from upper body force interaction in walker assisted gait.

PubMed

Frizera Neto, Anselmo; Gallego, Juan A; Rocon, Eduardo; Pons, José L; Ceres, Ramón

2010-08-05

The advances in technology make possible the incorporation of sensors and actuators in rollators, building safer robots and extending the use of walkers to a more diverse population. This paper presents a new method for the extraction of navigation related components from upper-body force interaction data in walker assisted gait. A filtering architecture is designed to cancel: (i) the high-frequency noise caused by vibrations on the walker's structure due to irregularities on the terrain or walker's wheels and (ii) the cadence related force components caused by user's trunk oscillations during gait. As a result, a third component related to user's navigation commands is distinguished. For the cancelation of high-frequency noise, a Benedict-Bordner g-h filter was designed presenting very low values for Kinematic Tracking Error ((2.035 +/- 0.358).10(-2) kgf) and delay ((1.897 +/- 0.3697).10(1)ms). A Fourier Linear Combiner filtering architecture was implemented for the adaptive attenuation of about 80% of the cadence related components' energy from force data. This was done without compromising the information contained in the frequencies close to such notch filters. The presented methodology offers an effective cancelation of the undesired components from force data, allowing the system to extract in real-time voluntary user's navigation commands. Based on this real-time identification of voluntary user's commands, a classical approach to the control architecture of the robotic walker is being developed, in order to obtain stable and safe user assisted locomotion.

Public provision of four-wheeled walkers: contingent valuation study of economic benefit.

PubMed

Haines, Terry; Brown, Cassandra; Morrison, Jan

2008-09-01

To quantify the economic value of publicly provided four-wheeled walkers as judged by recipients in Queensland, Australia. Contingent valuation study using willingness-to-pay approach. A sample of 49 Australian older adults who received a publicly funded four-wheeled walker in the past 3 months completed the survey via telephone. A discrete choice bidding response format with a randomly selected starting bid was employed to glean valuations. This approach yielded only one non-response, and one zero dollar response. The mean (standard deviation) valuation provided was $ A 290 ($ A 167), which was $ A 84 in excess of the price paid by the public provider agency to purchase the equipment. Starting bid was significantly associated with values provided. The current public provision program of four-wheeled walkers is likely to generate net societal benefit. These findings coupled with arguments based on equity build a moderate case for the continuation of this program.

Larval description of Copitarsia incommoda (Walker) (Lepidoptera: Noctuidae)

USDA-ARS?s Scientific Manuscript database

The last-instar larva of Copitarsia incommoda (Walker) is described for the first time. Specimens in this study were reared from quinoa (Chenopodium quinoa Willd., Chenopodiaceae), Bolivia, La Paz, 4 km S Viacha, Quipaquipani, 3880 m. The larva of Copitarsia incommoda is compared with larvae of Copi...

Quantum centipedes: collective dynamics of interacting quantum walkers

NASA Astrophysics Data System (ADS)

Krapivsky, P. L.; Luck, J. M.; Mallick, K.

2016-08-01

We consider the quantum centipede made of N fermionic quantum walkers on the one-dimensional lattice interacting by means of the simplest of all hard-bound constraints: the distance between two consecutive fermions is either one or two lattice spacings. This composite quantum walker spreads ballistically, just as the simple quantum walk. However, because of the interactions between the internal degrees of freedom, the distribution of its center-of-mass velocity displays numerous ballistic fronts in the long-time limit, corresponding to singularities in the empirical velocity distribution. The spectrum of the centipede and the corresponding group velocities are analyzed by direct means for the first few values of N. Some analytical results are obtained for arbitrary N by exploiting an exact mapping of the problem onto a free-fermion system. We thus derive the maximal velocity describing the ballistic spreading of the two extremal fronts of the centipede wavefunction, including its non-trivial value in the large-N limit.

Novel method to form adaptive internal impedance profiles in walkers.

PubMed

Escudero Morland, Maximilano F; Althoefer, Kaspar; Nanayakkara, Thrishantha

2015-01-01

This paper proposes a novel approach to improve walking in prosthetics, orthotics and robotics without closed loop controllers. The approach requires impedance profiles to be formed in a walker and uses state feedback to update the profiles in real-time via a simple policy. This approach is open loop and inherently copes with the challenge of uncertain environment. In application it could be used either online for a walker to adjust its impedance profiles in real-time to compensate for environmental changes, or offline to learn suitable profiles for specific environments. So far we have conducted simulations and experiments to investigate the transient and steady state gaits obtained using two simple update policies to form damping profiles in a passive dynamic walker known as the rimless wheel (RW). The damping profiles are formed in the motor that moves the RW vertically along a rail, analogous to a knee joint, and the two update equations were designed to a) control the angular velocity profile and b) minimise peak collision forces. Simulation results show that the velocity update equation works within limits and can cope with varying ground conditions. Experiment results show the angular velocity average reaching the target as well as the peak force update equation reducing peak collision forces in real-time.

Uranium transport in the Walker River Basin, California and Nevada

USGS Publications Warehouse

Benson, L.V.; Leach, D.L.

1979-01-01

During the summer of 1976 waters from tributaries, rivers, springs and wells were sampled in the Walker River Basin. Snow and sediments from selected sites were also sampled. All samples were analyzed for uranium and other elements. The resulting data provide an understanding of the transport of uranium within a closed hydrologic basin as well as providing a basis for the design of geochemical reconnaissance studies for the Basin and Range Province of the Western United States. Spring and tributary data are useful in locating areas containing anomalous concentrations of uranium. However, agricultural practices obscure the presence of known uranium deposits and render impossible the detection of other known deposits. Uranium is extremely mobile in stream waters and does not appear to sorb or precipitate. Uranium has a long residence time (2500 years) in the open waters of Walker Lake; however, once it crosses the sediment-water interface, it is reduced to the U(IV) state and is lost from solution. Over the past two million years the amount of uranium transported to the terminal point of the Walker River system may have been on the order of 4 ?? 108 kg. This suggests that closed basin termini are sites for significant uranium accumulations and are, therefore, potential sites of uranium ore deposits. ?? 1979.

Galilean generalized Robertson-Walker spacetimes: A new family of Galilean geometrical models

NASA Astrophysics Data System (ADS)

de la Fuente, Daniel; Rubio, Rafael M.

2018-02-01

We introduce a new family of Galilean spacetimes, the Galilean generalized Robertson-Walker spacetimes. This new family is relevant in the context of a generalized Newton-Cartan theory. We study its geometrical structure and analyse the completeness of its inextensible free falling observers. This sort of spacetimes constitutes the local geometric model of a much wider family of spacetimes admitting certain conformal symmetry. Moreover, we find some sufficient geometric conditions which guarantee a global splitting of a Galilean spacetime as a Galilean generalized Robertson-Walker spacetime.

Walker use, but not falls, is associated with lower physical functioning and health of residents in an assisted-living environment.

PubMed

Andersen, Daniel A; Roos, Bernard A; Stanziano, Damian C; Gonzalez, Natasha M; Signorile, Joseph F

2007-01-01

The relationship between perceived health and walker use has seldom been addressed. Concerns over falls and falls risk are precursors to walker use. We compared the SF-36 scores of 26 women and 14 men, mean age 86.8 +/- 6.0 years based on walker use and faller status. An analysis of covariance (ANCOVA) with age as the covariate, compared groups for the SF-36 constructs and totals score. Significant differences were noted between walker users and nonusers in physical functioning, role limitations due to physical problems, general health, and the total SF-36 score. Pairwise comparisons favored nonusers, while no differences were seen due to faller status. Walker use is associated with lower self-perceptions of physical functioning, role limitations due to physical problems, and general health in assisted-living residents. Faller status is not associated with self-perceived health status. Although walker use aids mobility and lowers the probability of falls, further research is needed to determine if the prescription of assistive devices has a more negative impact on self-perceived health than does falling. This possibility could be explained, in part, by the greater activity levels of those individuals who do not depend on walkers.

Two American Entrepreneurs: Madame C. J. Walker and J. C. Penney. Teaching with Historic Places.

ERIC Educational Resources Information Center

Koman, Rita

2000-01-01

This lesson is based on the National Historic Landmark files, "Madame C. J. Walker Building" and "J. C. Penney Historic District," as well as other relevant sources. The lesson first discusses the Indianapolis (Indiana) site of Madame Walker's cosmetics business. The building is a 4-story brick structure completed in 1927.…

Variability in energy cost and walking gait during race walking in competitive race walkers.

PubMed

Brisswalter, J; Fougeron, B; Legros, P

1998-09-01

The aim of this study was to examine the variability of energy cost (Cw) and race walking gait after a 3-h walk at the competition pace in race walkers of the same performance level. Nine competitive race walkers were studied. In the same week, after a first test of VO2max determination, each subject completed two submaximal treadmill walks (6 min length, 0% grade, 12 km X h(-1) speed) before and after a 3-h overground test completed at the individual competition speed of the race walker. During the two submaximal tests, subjects were filmed between the 2nd and the 4th min, and physiological parameters were recorded between the 4th and the 6th min. Results showed two trends. On the one hand, we observed a significant and systematic increase in energy cost of walking (mean deltaCw = 8.4%), whereas no variation in the gait kinematics prescribed by the rules of race walking was recorded. On the other hand, this increase in metabolic energy demand was accompanied by variations of different magnitude and direction of stride length, of the excursion of the heel and of the maximal ankle flexion at toe-off among the race walkers. These results indicated that competitive race walkers are able to maintain their walking gait with exercise duration apart from a systematic increase in energy cost. Moreover, in this form of locomotion the effect of fatigue on the gait variability seems to be an individual function of the race walk constraints and the constraints of the performer.

Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers.

PubMed

Zhang, Songning; Clowers, Kurt G; Powell, Douglas

2006-12-01

Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.

Dandy–Walker malformation: An incidental finding

PubMed Central

Tadakamadla, Jyothi; Kumar, Santhosh; Mamatha, G. P.

2010-01-01

Dandy–Walker malformation (DWM) is a rare intracranial congenital abnormality that affects the cerebellum and some of its components; particularly cerebellar vermis, fourth ventricle and is characterized by an enlarged posterior fossa. Although there is an extensive list of signs attributed to DWM, final diagnosis is solely dependent on imaging techniques as there are no signs that are characteristic of DWM. This article reports a case with DWM who was diagnosed by magnetic resonance imaging. PMID:20838490

Where Are They Now: Nathalie Walker Moves from Science to Activism and Art Communications | Poster

Cancer.gov

Whether it’s in a flowerbed or an art gallery, former Werner H. Kirsten (WHK) student intern Nathalie Walker can’t help but to cause a buzz. Since completing her WHK internship in the summer of 2015, Walker has been attending Loyola University Maryland, where she is striving to make a positive impact on campus.

[Stress parameters and behaviour of horses in walkers with and without the use of electricity].

PubMed

Giese, C; Gerber, V; Howald, M; Bachmann, I; Burger, D

2014-04-01

In order to investigate stress responses of horses in walkers with and without electricity, 12 horses were trained during 3 weeks in a horse walker with and without the use of electricity (3.7 kV). To evaluate the stress response, cortisol levels in the blood were measured, the heart rate was monitored using the Polar® system and the behaviour was evaluated. Neither the cortisol levels nor the heart rates showed any relevant statistically significant difference between horses moved in the horse walker with or without the use of electricity. The highest cortisol levels and heart rates were recorded during the first week (habituation period). A significant difference could be observed regarding spontaneous compartment changes: while this happened mainly during the first week and before the first use of electricity, no horses changed compartments in the periods when electricity was used and thereafter. The results of this study indicate that the use of electricity in the horse walker does not seem to cause significant detectable stress in the horses.

Exact solution of two interacting run-and-tumble random walkers with finite tumble duration

NASA Astrophysics Data System (ADS)

Slowman, A. B.; Evans, M. R.; Blythe, R. A.

2017-09-01

We study a model of interacting run-and-tumble random walkers operating under mutual hardcore exclusion on a one-dimensional lattice with periodic boundary conditions. We incorporate a finite, poisson-distributed, tumble duration so that a particle remains stationary whilst tumbling, thus generalising the persistent random walker model. We present the exact solution for the nonequilibrium stationary state of this system in the case of two random walkers. We find this to be characterised by two lengthscales, one arising from the jamming of approaching particles, and the other from one particle moving when the other is tumbling. The first of these lengthscales vanishes in a scaling limit where the continuous-space dynamics is recovered whilst the second remains finite. Thus the nonequilibrium stationary state reveals a rich structure of attractive, jammed and extended pieces.

A wrist-walker exhibiting no "Uner Tan Syndrome": a theory for possible mechanisms of human devolution toward the atavistic walking patterns.

PubMed

Tan, Uner

2007-01-01

After discovering two families with handicapped children exhibiting the "Uner Tan syndrome," the author discovered a man exhibiting only wrist-walking with no primitive mental abilities including language. According to his mother, he had an infectious disease with high fever as a three months old baby; as a result, the left leg had been paralyzed after a penicilline injection. This paralysis most probably resulted from a viral disease, possibly poliomyelitis. He is now (2006) 36 years old; the left leg is flaccid and atrophic, with no tendon reflexes; however, sensation is normal. The boy never stood up on his feet while maturing. The father forced him to walk upright using physical devices and making due exercises, but the child always rejected standing upright and walking in erect posture; he always preferred wrist-walking; he expresses that wrist-walking is much more comfortable for him than upright-walking. He is very strong now, making daily body building exercises, and walking quite fast using a "three legs," although he cannot stand upright. Mental status, including the language and conscious experience, is quite normal. There was no intra-familiar marriage as in the two families mentioned earlier, and there is no wrist-walking in his family and relatives. There were no cerebellar signs and symptoms upon neurological examination. The brain-MRI was normal; there was no atrophy in cerebellum and vermis. It was concluded that there may be sporadic wrist-walkers exhibiting no "Uner Tan Syndrome." The results suggest that the cerebellum has nothing to do with human wrist-walking, which may rather be an atavistic trait appearing from time to time in normal individuals, indicating a live model for human reverse evolution. It was concluded that pure quadrupeds may sporadically appear due to random fluctuations in genotypes and/or environmental factors (hormonal or nutritional); the human development following the human evolution may be stopped in the stage of

Ophthalmic profile and systemic features of pediatric facial nerve palsy.

PubMed

Patil-Chhablani, Preeti; Murthy, Sowmya; Swaminathan, Meenakshi

2015-12-01

Facial nerve palsy (FNP) occurs less frequently in children as compared to adults but most cases are secondary to an identifiable cause. These children may have a variety of ocular and systemic features associated with the palsy and need detailed ophthalmic and systemic evaluation. This was a retrospective chart review of all the cases of FNP below the age of 16 years, presenting to a tertiary ophthalmic hospital over the period of 9 years, from January 2000 to December 2008. A total of 22 patients were included in the study. The average age at presentation was 6.08 years (range, 4 months to 16 years). Only one patient (4.54%) had bilateral FNP and 21 cases (95.45%) had unilateral FNP. Seventeen patients (77.27%) had congenital palsy and of these, five patients had a syndromic association, three had birth trauma and nine patients had idiopathic palsy. Five patients (22.72%) had an acquired palsy, of these, two had a traumatic cause and one patient each had neoplastic origin of the palsy, iatrogenic palsy after surgery for hemangioma and idiopathic palsy. Three patients had ipsilateral sixth nerve palsy, two children were diagnosed to have Moebius syndrome, one child had an ipsilateral Duane's syndrome with ipsilateral hearing loss. Corneal involvement was seen in eight patients (36.36%). Amblyopia was seen in ten patients (45.45%). Neuroimaging studies showed evidence of trauma, posterior fossa cysts, pontine gliosis and neoplasms such as a chloroma. Systemic associations included hemifacial macrosomia, oculovertebral malformations, Dandy Walker syndrome, Moebius syndrome and cerebral palsy FNP in children can have a number of underlying causes, some of which may be life threatening. It can also result in serious ocular complications including corneal perforation and severe amblyopia. These children require a multifaceted approach to their care.

16 CFR 1216.2 - Requirements for infant walkers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... coefficient of friction = 0.05 NCAMI = Normal force (for CAMI dummy scenario) = weight of CAMI dummy and... occupant seating area and arms placed on the walker tray. (ii) [Reserved] (8) Instead of complying with... horizontally (0 ± 0.5° with respect to the table surface). (ii) [Reserved] (9) Instead of complying with...

Reliability of the Walker Cranial Nonmetric Method and Implications for Sex Estimation.

PubMed

Lewis, Cheyenne J; Garvin, Heather M

2016-05-01

The cranial trait scoring method presented in Buikstra and Ubelaker (Standards for data collection from human skeletal remains. Fayetteville, AR: Arkansas Archeological Survey Research Series No. 44, 1994) and Walker (Am J Phys Anthropol, 136, 2008 and 39) is the most common nonmetric cranial sex estimation method utilized by physical and forensic anthropologists. As such, the reliability and accuracy of the method is vital to ensure its validity in forensic applications. In this study, inter- and intra-observer error rates for the Walker scoring method were calculated using a sample of U.S. White and Black individuals (n = 135). Cohen's weighted kappas, intraclass correlation coefficients, and percentage agreements indicate good agreement between trials and observers for all traits except the mental eminence. Slight disagreement in scoring, however, was found to impact sex classifications, leading to lower accuracy rates than those published by Walker. Furthermore, experience does appear to impact trait scoring and sex classification. The use of revised population-specific equations that avoid the mental eminence is highly recommended to minimize the potential for misclassifications. © 2016 American Academy of Forensic Sciences.

Differences in the Limits of Stability Between Older Rolling Walker Users and Older Single-Tip-Cane Users - A Preliminary Study.

PubMed

Liu, Hao Howe; Quiben, Myles; Holmes, Clayton; Connors, Michael; Salem, Yasser

To identify the differences in the limits of stability (LOS) between older rolling walker and single-tip-cane users. This was a matched paired t-test design with repeated measure. Eighteen older subjects were matched based on age, gender, and functional level. The subjects were assessed using the multidirectional reach test initially and 5-month later in four directions: forward, backward, leftward, and rightward. Initially, there were no differences between cane users and rolling walker users in the LOS in all directions. However, 5-month later, the cane users who held their canes in their right hand had significantly better stability in forward and rightward reach than the walker users (p < .05). Further, the walker users demonstrated significantly decreased functional reach in forward reach (p < .05). Cane users might have better stability than walker users in the forward direction and in the direction toward the side holding the cane. This study may provide guide for clinicians including nurses for selecting appropriate rehabilitative interventions for older adults using walkers and canes.

Unintentional fall injuries associated with walkers and canes in older adults treated in U.S. emergency departments.

PubMed

Stevens, Judy A; Thomas, Karen; Teh, Leesia; Greenspan, Arlene I

2009-08-01

To characterize nonfatal, unintentional, fall-related injuries associated with walkers and canes in older adults. Surveillance data of injuries treated in hospital emergency departments (EDs), January 1, 2001, to December 31, 2006. The National Electronic Injury Surveillance System All Injury Program, which collects data from a nationally representative stratified probability sample of 66 U.S. hospital EDs. People aged 65 and older treated in EDs for 3,932 nonfatal unintentional fall injuries and whose records indicated that a cane or a walker was involved in the fall. Sex, age, whether the fall involved a cane or walker, primary diagnosis, part of the body injured, disposition, and location and circumstances of the fall. An estimated 47,312 older adult fall injuries associated with walking aids were treated annually in U.S. EDs: 87.3% with walkers, 12.3% with canes, and 0.4% with both. Walkers were associated with seven times as many injuries as canes. Women's injury rates exceeded those for men (rate ratios=2.6 for walkers, 1.4 for canes.) The most prevalent injuries were fractures and contusions or abrasions. Approximately one-third of subjects were hospitalized for their injuries. Injuries and hospital admissions for falls associated with walking aids were frequent in this highly vulnerable population. The results suggest that more research is needed to improve the design of walking aids. More information also is needed about the circumstances preceding falls, both to better understand the contributing fall risk factors and to develop specific and effective fall prevention strategies.

Finding the Right Formula: Edwin H. Walker Jr

ERIC Educational Resources Information Center

Keels, Crystal L.

2005-01-01

Edwin H. Walker Jr earned his doctorate in chemistry at age 27 and has barely looked back. With 13 publications under his belt before coming out of graduate school, he has also given more than 20 poster presentations in national venues, most recently at the American Chemical Society. He can also include securing a half-million-dollar National…

Two-walker discrete-time quantum walks on the line with percolation

NASA Astrophysics Data System (ADS)

Rigovacca, L.; di Franco, C.

2016-02-01

One goal in the quantum-walk research is the exploitation of the intrinsic quantum nature of multiple walkers, in order to achieve the full computational power of the model. Here we study the behaviour of two non-interacting particles performing a quantum walk on the line when the possibility of lattice imperfections, in the form of missing links, is considered. We investigate two regimes, statical and dynamical percolation, that correspond to different time scales for the imperfections evolution with respect to the quantum-walk one. By studying the qualitative behaviour of three two-particle quantities for different probabilities of having missing bonds, we argue that the chosen symmetry under particle-exchange of the input state strongly affects the output of the walk, even in noisy and highly non-ideal regimes. We provide evidence against the possibility of gathering information about the walkers indistinguishability from the observation of bunching phenomena in the output distribution, in all those situations that require a comparison between averaged quantities. Although the spread of the walk is not substantially changed by the addition of a second particle, we show that the presence of multiple walkers can be beneficial for a procedure to estimate the probability of having a broken link.

77 FR 67811 - Porter-Walker LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-14

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-327-000] Porter-Walker LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding of Porter-Walker...

Comparison of spatiotemporal and energy cost of the use of 3 different walkers and unassisted walking in older adults.

PubMed

Protas, Elizabeth J; Raines, Mary Lynn; Tissier, Sandrine

2007-06-01

To compare temporal, spatial, and oxygen costs of gait while elderly subjects walked without an assistive device, with a new assistive device, and with 2 other commercially available assistive devices. Descriptive, repeated measures. University-based research laboratory. Thirteen healthy older subjects who could walk without an assistive device. Not applicable. Gait speed, normalized gait speed, cadence, stride lengths, 5-minute walk distance and gait speed, oxygen consumption (Vo2) per meter walked, respiratory exchange ratio (RER) per meter walked, and minute ventilation per meter walked. Gait speed, normalized gait speed, and stride lengths decreased when the Merry Walker device was used, compared with walking without an assistive device. Outcome measures when walking with either the wheeled walker or the WalkAbout did not differ significantly from walking without a device except for a faster cadence with the WalkAbout. The distance walked and gait speed were decreased and the RER and minute ventilation were increased during the 5-minute walk with the Merry Walker compared with normal walking. The Vo2 was higher with the wheeled walker and Merry Walker than when walking without an assistive device, but there was no difference when the WalkAbout was used. Older adults walked in the new assistive device, the WalkAbout, with parameters that did not differ significantly from their gait without a device. The oxygen demands of walking were similar to unassisted walking for the WalkAbout, but were higher for the wheeled walker and Merry Walker. These results may help guide the prescription of assistive devices for older adults.

Uniparental disomy and prenatal phenotype: Two case reports and review.

PubMed

Li, Xiaofei; Liu, Yan; Yue, Song; Wang, Li; Zhang, Tiejuan; Guo, Cuixia; Hu, Wenjie; Kagan, Karl-Oliver; Wu, Qingqing

2017-11-01

Uniparental disomy (UPD) gives a description of the inheritance of both homologues of a chromosome pair from the same parent. The consequences of UPD depend on the specific chromosome/segment involved and its parental origin. We report prenatal phenotypes of 2 rare cases of UPD. The prenatal phenotype of case 1 included sonographic markers such as enlarged nuchal translucency (NT), absent nasal bone, short femur and humerus length, and several structural malformations involving Dandy-Walker malformation and congenital heart defects. The prenatal phenotype of Case 2 are sonographic markers, including enlarged NT, thickened nuchal fold, ascites, and polyhydramnios without apparent structural malformations. Conventional G-band karyotype appears normal in case 1, while it shows normal chromosomes with a small supernumerary marker chromosome (sSMC) in case 2. Genetic etiology was left unknown until single-nucleotide polymorphism-based array (SNP-array) was performed, and segmental paternal UPD 22 was identified in case 1 and segmental paternal UPD 14 was found in case 2. The parents of case 1 chose termination of pregnancy. The neonate of case 2 was born prematurely with a bellshaped small thorax and died within a day. UPD cases are rare and the phenotypes are different, which depend on the origin and affected chromosomal part. If a fetus shows multiple anomalies that cannot be attributed to a common aneuploidy or a genetic syndrome, or manifests some features possibly related to an UPD syndrome, such as detection of sSMC, SNP-array should be considered.

Walker,Wheelock and Yurchikhin in MRM-1

NASA Image and Video Library

2010-11-19

ISS025-E-017118 (22 Nov. 2010)--- From left, NASA astronaut Shannon Walker, Expedition 25 flight engineer; NASA astronaut Doug Wheelock, Expedition 25 commander; and Russian cosmonaut Fyodor Yurchikhin, flight engineer, are all suited up in their Sokol (Russian word for 'Falcon') pressure suits in the Russian MRM-1 module aboard the Earth-orbiting International Space Station. They ingressed the docked Soyuz capsule to conduct pressurization and leak checks on their suits.

Hidden marker position estimation during sit-to-stand with walker.

PubMed

Yoon, Sang Ho; Jun, Hong Gul; Dan, Byung Ju; Jo, Byeong Rim; Min, Byung Hoon

2012-01-01

Motion capture analysis of sit-to-stand task with assistive device is hard to achieve due to obstruction on reflective makers. Previously developed robotic system, Smart Mobile Walker, is used as an assistive device to perform motion capture analysis in sit-to-stand task. All lower limb markers except hip markers are invisible through whole session. The link-segment and regression method is applied to estimate the marker position during sit-to-stand. Applying a new method, the lost marker positions are restored and the biomechanical evaluation of the sit-to-stand movement with a Smart Mobile Walker could be carried out. The accuracy of the marker position estimation is verified with normal sit-to-stand data from more than 30 clinical trials. Moreover, further research on improving the link segment and regression method is addressed.

l-Glutamine supplementation promotes an improved energetic balance in Walker-256 tumor-bearing rats.

PubMed

Martins, Heber Amilcar; Bazotte, Roberto Barbosa; Vicentini, Geraldo Emilio; Lima, Mariana Machado; Guarnier, Flavia Alessandra; Hermes-Uliana, Catchia; Frez, Flavia Cristina Vieira; Bossolani, Gleison Daion Piovezana; Fracaro, Luciane; Fávaro, Larissa Dos Santos; Manzano, Mariana Inocêncio; Zanoni, Jacqueline Nelisis

2017-03-01

We evaluated the effects of supplementation with oral l-glutamine in Walker-256 tumor-bearing rats. A total of 32 male Wistar rats aged 54 days were randomly divided into four groups: rats without Walker-256 tumor, that is, control rats (C group); control rats supplemented with l-glutamine (CG group); Walker-256 tumor rats without l-glutamine supplementation (WT group); and WT rats supplemented with l-glutamine (WTG group). l-Glutamine was incorporated into standard food at a proportion of 2 g/100 g (2%). After 10 days of the experimental period, the jejunum and duodenum were removed and processed. Protein expression levels of key enzymes of gluconeogenesis, that is, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, were analyzed by western blot and immunohistochemical techniques. In addition, plasma corticosterone, glucose, insulin, and urea levels were evaluated. The WTG group showed significantly increased plasma glucose and insulin levels ( p < 0.05); however, plasma corticosterone and urea remained unchanged. Moreover, the WTG group showed increased immunoreactive staining for jejunal phosphoenolpyruvate carboxykinase and increased expression of duodenal glucose-6-phosphatase. Furthermore, the WTG group presented with less intense cancer cachexia and slower tumor growth. These results could be attributed, at least partly, to increased intestinal gluconeogenesis and insulinemia, and better glycemia maintenance during fasting in Walker-256 tumor rats on a diet supplemented with l-glutamine.

Walker Ranch 3D seismic images

DOE Data Explorer

Robert J. Mellors

2016-03-01

Amplitude images (both vertical and depth slices) extracted from 3D seismic reflection survey over area of Walker Ranch area (adjacent to Raft River). Crossline spacing of 660 feet and inline of 165 feet using a Vibroseis source. Processing included depth migration. Micro-earthquake hypocenters on images. Stratigraphic information and nearby well tracks added to images. Images are embedded in a Microsoft Word document with additional information. Exact location and depth restricted for proprietary reasons. Data collection and processing funded by Agua Caliente. Original data remains property of Agua Caliente.

Comparative Study of Assisted Ambulation and Perceived Exertion With the Wheeled Knee Walker and Axillary Crutches in Healthy Subjects.

PubMed

Kocher, Benjamin K; Chalupa, Robyn L; Lopez, Donna M; Kirk, Kevin L

2016-11-01

Functional limitations after lower extremity surgery often require the use of an assistive device for ambulation during rehabilitation and recovery. There are no known objective data evaluating the wheeled knee walker as an assistive device for protected ambulation. The purpose of this study was to compare assisted ambulation and perceived exertion with the wheeled knee walker and the axillary crutches in healthy participants. A prospective, randomized crossover study was performed using 24 healthy volunteers. Each participant performed a 6-minute walk test (6MWT) using each assistive device in a crossover manner. Preactivity and postactivity heart rates were recorded. The self-selected walking velocity (SSWV) was calculated and the participant's rating of perceived exertion was recorded using the OMNI Rating of Perceived Exertion (OMNI-RPE). Participant's preference for assistive device was identified. The 6MWT, SSWV, and the Omni-RPE were evaluated using paired t tests and determined to be statistically significant for the wheeled knee walker compared with axillary crutches. Evaluation of the preactivity and postactivity heart rates demonstrated a statistically significant difference for the wheeled knee walker compared with axillary crutches. The wheeled knee walker was preferred by 88% of participants. The wheeled knee walker provided increased assisted ambulation and had a lower rating of perceived exertion than axillary crutches on level surfaces in healthy participants. Level III, comparative study. © The Author(s) 2016.

Dynamic optimization of walker-assisted FES-activated paraplegic walking: simulation and experimental studies.

PubMed

Nekoukar, Vahab; Erfanian, Abbas

2013-11-01

In this paper, we propose a musculoskeletal model of walker-assisted FES-activated paraplegic walking for the generation of muscle stimulation patterns and characterization of the causal relationships between muscle excitations, multi-joint movement, and handle reaction force (HRF). The model consists of the lower extremities, trunk, hands, and a walker. The simulation of walking is performed using particle swarm optimization to minimize the tracking errors from the desired trajectories for the lower extremity joints, to reduce the stimulations of the muscle groups acting around the hip, knee, and ankle joints, and to minimize the HRF. The results of the simulation studies using data recorded from healthy subjects performing walker-assisted walking indicate that the model-generated muscle stimulation patterns are in agreement with the EMG patterns that have been reported in the literature. The experimental results on two paraplegic subjects demonstrate that the proposed methodology can improve walking performance, reduce HRF, and increase walking speed when compared to the conventional FES-activated paraplegic walking. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

STS-69 Mission Commander David M. Walker in white room

NASA Technical Reports Server (NTRS)

1995-01-01

STS-69 Mission Commander David M. Walker chats with white room closeout crew members Bob Saulnier (left), Regulo Villalobos and closeout crew leader Travis Thompson prior to entering the flight deck of the Space Shuttle Endeavour at Launch Pad 39A.

Walker photographs BCAT-5 (Binary Colloidal Alloy Test-5) payload

NASA Image and Video Library

2010-10-19

ISS025-E-008239 (19 Oct. 2010) --- NASA astronaut Shannon Walker, Expedition 25 flight engineer, uses a digital still camera to photograph Binary Colloidal Alloy Test-5 (BCAT-5) experiment samples in the Kibo laboratory of the International Space Station.

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index.

PubMed

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D K; Leong, John C Y

2009-12-01

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index

NASA Astrophysics Data System (ADS)

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D. K.; Leong, John C. Y.

2009-12-01

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

Test pilots 1962 - Thompson, McKay, Dana, Armstrong, Peterson, Butchart, Walker

NASA Technical Reports Server (NTRS)

1962-01-01

A group photo of NASA research pilots at the front door of the Flight Research Center headquarters building. In the front row are (left to right) Milt Thompson, Jack McKay, and Bill Dana. All three flew the X-15, and Thompson and Dana were also involved in the lifting body flights. McKay was injured in a crash landing in X-15 #2. Although he recovered, the injuries eventually forced him to retire from research flying. In the back row (left to right) are Neil Armstrong, Bruce Peterson, Stanley Butchart, and Joe Walker. Armstrong and Walker also both flew the X-15. Soon after this photo was taken, Armstrong was selected as an astronaut, and seven years later became the first man to walk on the Moon. Walker made the highest flight in the X-15, reaching 354,200 feet. He then went on to fly the Lunar Landing Research Vehicle, and was killed on June 8, 1966 when his F-104N collided with the XB-70. Peterson made the first flight in the HL-10 lifting body, and was later badly injured in the crash of the M2-F2 lifting body. Butchart flew a wide range of research missions in the 1950s, and was the B-29 drop plane pilot for a number of rocket flight.

Walking on the edge: meanings of living in an ageing body and using a walker in everyday life - a phenomenological hermeneutic study.

PubMed

Brännström, Helene; Bäckman, Margit; Santamäki Fischer, Regina

2013-05-01

In order to maintain one's state of health whilst growing older, the ability to walk is essential. The aim of this study was to illuminate the meanings of the lived experience of living in an ageing body and using a walker in daily life. Narrative interviews were performed with seven older persons aged 79-95 years. The transcribed text was analysed using a phenomenological hermeneutic method. The key finding of the study was that the lived experience of living in an ageing body and using a walker in daily life was interpreted as 'walking on the edge' based on the themes 'Being vulnerable and dependent' and 'Being confident and independent'. The results highlight the importance of reflecting on this phenomenon as a health care professional while meeting the care needs of older persons who use walkers. Nurses need to consider the walker as a personal and valued possession of the individual and handle the walker in agreement with the older person, placing the walker close at hand with the brakes locked to give secure support. © 2012 Blackwell Publishing Ltd.

The oophorectomy effect on Walker 256 tumor inoculated into the vagina and uterine cervix of female rats.

PubMed

Brito, Nara Macedo Botelho; Carvalho, Rita de Kássia Vidigal; Matos, Lia Tavares de Moura Brasil; Lobato, Rodolfo Costa; Brito, Rosângela Baía

2009-01-01

Verify the effect of oophorectomy on the evolution of the Walker 256 tumor inoculated into the vagina and cervix of female rats. Ten Wistar, female rats were used, distributed into two groups with 05 animals each: Tumor group (TG): Rats inoculated with Walker 256 tumor; Oophorectomy group (OG): oophorectomized rats inoculated with Walker 256 tumor. The day before the tumor vaginal inoculation, acetic acid was inoculated into the vaginas of both groups of rats; the following day, the vaginal walls were scarified with an endocervix brush, and then Walker 256 tumor was inoculated. After 12 days, the tumor was removed together with the vagina and uterine horns for macro and microscopic analyses. The data were submitted to statistical analyses. There was no statistical difference between the two groups; however it was observed that the behavior of tumor growth on the OG group presented greater invasion, compromising the uterine horns. The results of the study on the GO group presented a macroscopic behavior different from the TG group, however, both of them presented similar development in terms of tumor mass.

Anisotropic evolution of 5D Friedmann-Robertson-Walker spacetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Middleton, Chad A.; Stanley, Ethan

2011-10-15

We examine the time evolution of the five-dimensional Einstein field equations subjected to a flat, anisotropic Robertson-Walker metric, where the 3D and higher-dimensional scale factors are allowed to dynamically evolve at different rates. By adopting equations of state relating the 3D and higher-dimensional pressures to the density, we obtain an exact expression relating the higher-dimensional scale factor to a function of the 3D scale factor. This relation allows us to write the Friedmann-Robertson-Walker field equations exclusively in terms of the 3D scale factor, thus yielding a set of 4D effective Friedmann-Robertson-Walker field equations. We examine the effective field equations inmore » the general case and obtain an exact expression relating a function of the 3D scale factor to the time. This expression involves a hypergeometric function and cannot, in general, be inverted to yield an analytical expression for the 3D scale factor as a function of time. When the hypergeometric function is expanded for small and large arguments, we obtain a generalized treatment of the dynamical compactification scenario of Mohammedi [Phys. Rev. D 65, 104018 (2002)] and the 5D vacuum solution of Chodos and Detweiler [Phys. Rev. D 21, 2167 (1980)], respectively. By expanding the hypergeometric function near a branch point, we obtain the perturbative solution for the 3D scale factor in the small time regime. This solution exhibits accelerated expansion, which, remarkably, is independent of the value of the 4D equation of state parameter w. This early-time epoch of accelerated expansion arises naturally out of the anisotropic evolution of 5D spacetime when the pressure in the extra dimension is negative and offers a possible alternative to scalar field inflationary theory.« less

11. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects October 28, 1904 BLUEPRINT OF ORIGINAL DRAWING OF NORTH ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

Infantile osteopetrosis and juvenile xanthogranuloma presenting together in a newborn: a case report and literature review.

PubMed

Almarzooqi, Saeeda; Reed, Suzanne; Fung, Bonita; Boué, Daniel R; Prasad, Vinay; Pietryga, Daniel

2011-01-01

Osteopetrosis (OP) is a clinically and genetically heterogeneous disorder characterized by increased bone density. Associations between OP and other clinical entities are rare but include muscular degeneration, Dandy-Walker syndrome, craniosynostosis, and poikiloderma. Infantile OP has also been diagnosed in a group of infants with neuronal storage disease. An association between OP and juvenile xanthogranuloma (JXG) has never been previously reported. Herein we present a case of an intermediate form of OP in a newborn who presented with hepatosplenomegaly and pancytopenia. Histologic evaluation of a bone marrow biopsy demonstrated abnormally thickened bony trabeculae. A liver biopsy demonstrated prominent expansion of portal areas by a histiocytic infiltrate expressing CD45, CD14, CD68, CD163, factor XIIIa, and fascin, while the biopsy was negative for S100 and CD1a. These findings were those associated with JXG. Genetic testing demonstrated a mutation involving the Pleckstrin homology domain-containing family M member 1 ( PLEKHM1 ) gene. A different mutation in this gene has been previously reported in one other patient with OP. Our case is the 2nd reported case with PLEKHM1 mutation in a patient with a mild form of OP. It also demonstrates the 1st reported occurrence of OP concomitantly with JXG.

Experimental Studies of Wheelchair and Walker Users Passing Through Doors with Different Opening Force.

PubMed

Nersveen, Jonny

2016-01-01

Users of walkers and users of different categories of wheelchairs tested doors with different opening force, aiming to reveal the limit that these groups of people could manage on an everyday basis. 94.7% of the wheelchair users reported that a door opening force of 30 N was acceptable, while as 92.1% of this group described 40 N as acceptable. Similarly, 100% of the walker users reported that a door opening force of 30 N was acceptable, while as 87,5% of this group described 40 N as acceptable.

75 FR 49517 - Notice of Intent To Prepare an Environmental Impact Statement for the Walker Ridge Wind Project...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

... system. The proposed action would include up to 42 wind turbine generators, an underground electrical...] Notice of Intent To Prepare an Environmental Impact Statement for the Walker Ridge Wind Project, Lake and...: You may submit comments related to the Walker Ridge Wind Project by any of the following methods: Web...

Mercury in the Walker River Basin, Nevada and California--sources, distribution, and potential effects on the ecosystem

USGS Publications Warehouse

Seiler, Ralph L.; Lico, Michael S.; Wiemeyer Evers, David C.

2004-01-01

Mercury is one of the most serious contaminants of water, sediment, and biota in Nevada because of its use during 19th century mining activities to recover gold and silver from ores. In 1998, mercury problems were discovered in the Walker River Basin of California and Nevada when blood drawn from three common loons from Walker Lake was analyzed and found to have severely elevated mercury levels. From 1999 to 2001, the U.S. Geological Survey and the U.S. Fish and Wildlife Service collected water, sediment, and biological samples to determine mercury sources, distribution, and potential effects on the Walker River Basin ecosystem. Total-mercury concentrations ranged from 0.62 to 57.11 ng/L in streams from the Walker River system and ranged from 1.02 to 26.8 ng/L in lakes and reservoirs. Total-mercury concentrations in streambed sediment ranged from 1 to 13,600 ng/g, and methylmercury concentrations ranged from 0.07 to 32.1 ng/g. The sediment-effects threshold for mercury for fresh-water invertebrates is 200 ng/g, which was exceeded at nine stream sites in the Walker River Basin. The highest mercury concentrations were in streams with historic mines and milling operations in the watershed. The highest mercury concentration in sediment, 13,600 ng/g, was found in Bodie Creek near Bodie, Calif., a site of extensive gold mining and milling activities during the 19th century. Sediment cores taken from Walker Lake show total-mercury concentrations exceeding 1,000 ng/g at depths greater than 15 cm below lake bottom. The presence of 137Cs above 8 cm in one core indicates that the upper 8 cm was deposited sometime after 1963. The mercury peak at 46 cm in that core, 2,660 ng/g, likely represents the peak of mining and gold extraction in the Bodie and Aurora mining districts between 1870 and 1880. Mercury concentrations in aquatic invertebrates at all sites downstream from mining activities in the Rough Creek watershed, which drains the Bodie and Aurora mining districts, were

Multi-pedal DNA walker biosensors based on catalyzed hairpin assembly and isothermal strand-displacement polymerase reaction for the chemiluminescent detection of proteins.

PubMed

Li, Ningxing; Du, Mingyuan; Liu, Yucheng; Ji, Xinghu; He, Zhike

2018-06-25

Two kinds of sensitive biosensors based on multi-pedal DNA walker along a 3-D DNA functional magnet particles track for the chemiluminescent detection of streptavidin are constructed and compared in this study. In the presence of SA, multi-pedal DNA walker has been constructed by biotin-modified catalyst as a result of the terminal protection for avoiding the digestion by exonuclease I. Then a toehold of CHA-H1 conjugated with magnetic microparticles (MMPs) could interact with a 'leg' of multi-pedal DNA walker to open the hairpin via toehold-mediated strand exchange catalysis. A newly exposed DNA segment in CHA-H1 would be hybridized with a toehold of biotin-labeled H2. Via the strand displacement process, H2 displaces one 'leg' of multi-pedal DNA walker, and the other 'leg' could still hybridize with neighboring H1 to initiate the next cycle. In order to solve the high background caused by the hybridization between CHA-H1 and H2 without CHA-catalyst, the other model has been designed. The principle of the other model (ISDPR DNA walker) is similar to the above one. After the terminal protection of SA, a 'leg' of multi-pedal DNA walker triggers the opening of the hairpin of ISDPR-H1 conjugated with MMPs. Then the biotin-modified primer could hybridize with the open stem, triggering the polymerization reaction in the presence of dNTPs/polymerase. As the extension of the primer, the 'leg' of multi-pedal DNA walker is displaced so that the other 'leg' could trigger proximal H1 to go on the next cycle. Due to its lower background and stronger signal, multi-pedal DNA walker based on ISDPR has a lower limit of detection for SA. The limit of detection (LOD) for SA is 6.5 pM. What's more, these DNA walker methods have been applied in complex samples successfully.

9. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects September 21, 1904 (Revised October 21, 1904) BLUEPRINT OF ORIGINAL DRAWING OF SOUTH ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

12. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects September 23, 1904 (Revised October 28, 1904) BLUEPRINT OF ORIGINAL DRAWING OF EAST ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

10. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Historic American Buildings Survey Mr. Walker, Draftsman of Hebbard and Gill, Architects September 21, 1904 (Revised October 28, 1904) BLUEPRINT OF ORIGINAL DRAWING OF WEST ELEVATION From the Collection of the San Diego Historical Society - George W. Marston House, 3525 Seventh Avenue, San Diego, San Diego County, CA

Monocoque structure for the SKITTER three-legged walker

NASA Astrophysics Data System (ADS)

Bansek, Robert N.; Booth, Andrew J.; Daneman, Steven A.; Dresser, James A.; Haney, Todd G.; Johnson, Gregory R.; Lindzen, Eric C.; Montgomery, Robert C.; Warren, Andrew L.

1988-06-01

The SKITTER 2 design is a monocoque version of the proposed lunar three-legged walker. By the definition of monocoque, the body and legs are a shell with no internal ribbing or supports added for absorbing stresses. The purpose of the monocoque is to encase the elements used for power transmission, power supply, and control of the motion. The material for the structure is a vinyl ester resin, Derakane 8084. This material is easily formable and locally obtainable. The body consists of a hexagonally shaped cylinder with truncated hexagonal pyramids on the top and botton. The legs are eight inch diameter cylinders. The legs are comprised of a tibia section and a femur section. The SKITTER 2 is powered by six actuators which provide linear forces that are transformed into rotary torques by a series of chains and sprockets. The joints connect the femur to the body and the tibia to the femur. Surrounding the joints are flexible rubber hoses that fully encase the chains and sprockets. The SKITTER 2 is capable of walking upside down, righting itself after being overturned, and has the ability to perform in many environments. Applications for this walker include lunar transport or drilling, undersea exploration, and operation in severe surroundings such as arctic temperatures or high radiation.

Monocoque structure for the SKITTER three-legged walker

NASA Technical Reports Server (NTRS)

Bansek, Robert N.; Booth, Andrew J.; Daneman, Steven A.; Dresser, James A.; Haney, Todd G.; Johnson, Gregory R.; Lindzen, Eric C.; Montgomery, Robert C.; Warren, Andrew L.

1988-01-01

The SKITTER 2 design is a monocoque version of the proposed lunar three-legged walker. By the definition of monocoque, the body and legs are a shell with no internal ribbing or supports added for absorbing stresses. The purpose of the monocoque is to encase the elements used for power transmission, power supply, and control of the motion. The material for the structure is a vinyl ester resin, Derakane 8084. This material is easily formable and locally obtainable. The body consists of a hexagonally shaped cylinder with truncated hexagonal pyramids on the top and botton. The legs are eight inch diameter cylinders. The legs are comprised of a tibia section and a femur section. The SKITTER 2 is powered by six actuators which provide linear forces that are transformed into rotary torques by a series of chains and sprockets. The joints connect the femur to the body and the tibia to the femur. Surrounding the joints are flexible rubber hoses that fully encase the chains and sprockets. The SKITTER 2 is capable of walking upside down, righting itself after being overturned, and has the ability to perform in many environments. Applications for this walker include lunar transport or drilling, undersea exploration, and operation in severe surroundings such as arctic temperatures or high radiation.

FE Walker refills the ITCS with the FSS in the US Lab

NASA Image and Video Library

2010-08-31

ISS024-E-012969 (31 Aug. 2010) --- NASA astronaut Shannon Walker, Expedition 24 flight engineer, works with the Fluid Servicing System (FSS) in the Destiny laboratory of the International Space Station.

Accommodation of missing shear strain in the Central Walker Lane, western North America: Constraints from dense GPS measurements

NASA Astrophysics Data System (ADS)

Bormann, Jayne M.; Hammond, William C.; Kreemer, Corné; Blewitt, Geoffrey

2016-04-01

We present 264 new interseismic GPS velocities from the Mobile Array of GPS for Nevada Transtension (MAGNET) and continuous GPS networks that measure Pacific-North American plate boundary deformation in the Central Walker Lane. Relative to a North America-fixed reference frame, northwestward velocities increase smoothly from ∼4 mm/yr in the Basin and Range province to 12.2 mm/yr in the central Sierra Nevada resulting in a Central Walker Lane deformation budget of ∼8 mm/yr. We use an elastic block model to estimate fault slip and block rotation rates and patterns of deformation from the GPS velocities. Right-lateral shear is distributed throughout the Central Walker Lane with strike-slip rates generally <1.5 mm/yr predicted by the block model, but extension rates are highest near north-striking normal faults found along the Sierra Nevada frontal fault system and in a left-stepping, en-echelon series of asymmetric basins that extend from Walker Lake to Lake Tahoe. Neotectonic studies in the western Central Walker Lane find little evidence of strike-slip or oblique faulting in the asymmetric basins, prompting the suggestion that dextral deformation in this region is accommodated through clockwise block rotations. We test this hypothesis and show that a model relying solely on the combination of clockwise block rotations and normal faulting to accommodate dextral transtensional strain accumulation systematically misfits the GPS data in comparison with our preferred model. This suggests that some component of oblique or partitioned right-lateral fault slip is needed to accommodate shear in the asymmetric basins of the western Central Walker Lane. Present-day clockwise vertical axis rotation rates in the Bodie Hills, Carson Domain, and Mina Deflection are between 1-4°/Myr, lower than published paleomagnetic rotation rates, suggesting that block rotation rates have decreased since the Late to Middle Miocene.

Spruce aphid (Elatobium abietinum Walker) (Hemiptera: Aphididae) [Chapter XXIV

Treesearch

Ann M. Lynch

2014-01-01

Elatobium abietinum Walker is a spruce-feeding aphid that in Europe is referred to as the green spruce aphid (Day et al., 1998a) (Fig. 1). However, in North America E. abietinum is known simply as the spruce aphid, while the common name "green spruce aphid" refers to a different species, Cinara fornacula Hottes (Hemiptera: Aphididae) (http://www.entsoc.org/...

New Walkers with Down Syndrome Use Cautious but Effective Strategies for Crossing Obstacles

ERIC Educational Resources Information Center

Mulvey, Genna M.; Kubo, Masayoshi; Chang, Chia-Lin; Ulrich, Beverly D.

2011-01-01

Perception of affordances research in children with developmental disabilities has only examined well practiced skills. Ten toddlers with Down syndrome and 10 with typical development walked across a GAITRite mat, with and without an obstacle. We coded the toddlers' behaviors after 1 and 3 months of walking experience when they encountered the…

Genetic, chromosomal, and syndromic causes of neural tube defects.

PubMed

Seidahmed, Mohammed Z; Abdelbasit, Omer B; Shaheed, Meeralebbae M; Alhussein, Khalid A; Miqdad, Abeer M; Samadi, Abdulmohsen S; Khalil, Mohammed I; Al-Mardawi, Elham; Salih, Mustafa A

2014-12-01

To ascertain the incidence, and describe the various forms of neural tube defects (NTDs) due to genetic, chromosomal, and syndromic causes. We carried out a retrospective analysis of data retrieved from the medical records of newborn infants admitted to the Neonatal Intensive Care Unit with NTDs and their mothers spanning 14 years (1996-2009) at the Security Forces Hospital, Riyadh, Saudi Arabia. The cases were ascertained by a perinatologist, neonatologist, geneticist, radiologist, and neurologist. The literature was reviewed via a MEDLINE search. Only liveborn babies were included. Permission from the Educational Committee at the Security Forces Hospital was obtained prior to the collection of data. Out of 103 infants with NTDs admitted during this period, 20 (19.4%) were found to have an underlying genetic syndromic, chromosomal and/or other anomalies. There were 5 cases of Meckel-Gruber syndrome, 2 Joubert syndrome, one Waardenburg syndrome, one Walker-Warburg syndrome, 2 chromosomal disorders, 2 caudal regression, one amniotic band disruption sequence, one associated with omphalocele, one with diaphragmatic hernia, and 4 with multiple congenital anomalies. There is a high rate of underlying genetic syndromic and/or chromosomal causes of NTDs in the Saudi Arabian population due to the high consanguinity rate. Identification of such association can lead to more accurate provisions of genetic counseling to the family including preimplantation genetic diagnosis or early termination of pregnancies associated with lethal conditions.

Aerobic Exercise Training Attenuates Tumor Growth and Reduces Insulin Secretion in Walker 256 Tumor-Bearing Rats

PubMed Central

Moreira, Veridiana Mota; da Silva Franco, Claudinéia Conationi; Prates, Kelly Valério; Gomes, Rodrigo Mello; de Moraes, Ana Maria Praxedes; Ribeiro, Tatiane Aparecida; Martins, Isabela Peixoto; Previate, Carina; Pavanello, Audrei; Matiusso, Camila Cristina Ianoni; Almeida, Douglas Lopes; Francisco, Flávio Andrade; Malta, Ananda; Tófolo, Laize Peron; da Silva Silveira, Sandra; Saavedra, Lucas Paulo Jacinto; Machado, Katia; da Silva, Paulo Henrique Olivieri; Fabrício, Gabriel S.; Palma-Rigo, Kesia; de Souza, Helenir Medri; de Fátima Silva, Flaviane; Biazi, Giuliana Regina; Pereira, Taís Susane; Vieira, Elaine; Miranda, Rosiane Aparecida; de Oliveira, Júlio Cezar; da Costa Lima, Luiz Delmar; Rinaldi, Wilson; Ravanelli, Maria Ida; de Freitas Mathias, Paulo Cezar

2018-01-01

Aerobic exercise training can improve insulin sensitivity in many tissues; however, the relationship among exercise, insulin, and cancer cell growth is unclear. We tested the hypothesis that aerobic exercise training begun during adolescence can attenuate Walker 256 tumor growth in adult rats and alter insulin secretion. Thirty-day-old male Wistar rats engaged in treadmill running for 8 weeks, 3 days/week, 44 min/day, at 55–65% VO2max until they were 90 days old (TC, Trained Control). An equivalently aged group was kept inactive during the same period (SC, Sedentary Control). Then, half the animals of the SC and TC groups were reserved as the control condition and the other half were inoculated with Walker 256 cancer cells, yielding two additional groups (Sedentary Walker and Trained Walker). Zero mortalities were observed in tumor-bearing rats. Body weight (BW), food intake, plasma glucose, insulin levels, and peripheral insulin sensitivity were analyzed before and after tumor cell inoculation. We also evaluated tumor growth, metastasis and cachexia. Isolated pancreatic islets secretory activity was analyzed. In addition, we evaluated mechanic sensibility. Our results showed improved physical performance according to the final workload and VO2max and reduced BW in trained rats at the end of the running protocol. Chronic adaptation to the aerobic exercise training decreased tumor weight, cachexia and metastasis and were associated with low glucose and insulin levels and high insulin sensitivity before and after tumor cell inoculation. Aerobic exercise started at young age also reduced pancreatic islet insulin content and insulin secretion in response to a glucose stimulus, without impairing islet morphology in trained rats. Walker 256 tumor-bearing sedentary rats also presented reduced pancreatic islet insulin content, without changing insulin secretion through isolated pancreatic islets. The mechanical sensitivity test indicated that aerobic exercise training

Aerobic Exercise Training Attenuates Tumor Growth and Reduces Insulin Secretion in Walker 256 Tumor-Bearing Rats.

PubMed

Moreira, Veridiana Mota; da Silva Franco, Claudinéia Conationi; Prates, Kelly Valério; Gomes, Rodrigo Mello; de Moraes, Ana Maria Praxedes; Ribeiro, Tatiane Aparecida; Martins, Isabela Peixoto; Previate, Carina; Pavanello, Audrei; Matiusso, Camila Cristina Ianoni; Almeida, Douglas Lopes; Francisco, Flávio Andrade; Malta, Ananda; Tófolo, Laize Peron; da Silva Silveira, Sandra; Saavedra, Lucas Paulo Jacinto; Machado, Katia; da Silva, Paulo Henrique Olivieri; Fabrício, Gabriel S; Palma-Rigo, Kesia; de Souza, Helenir Medri; de Fátima Silva, Flaviane; Biazi, Giuliana Regina; Pereira, Taís Susane; Vieira, Elaine; Miranda, Rosiane Aparecida; de Oliveira, Júlio Cezar; da Costa Lima, Luiz Delmar; Rinaldi, Wilson; Ravanelli, Maria Ida; de Freitas Mathias, Paulo Cezar

2018-01-01

Aerobic exercise training can improve insulin sensitivity in many tissues; however, the relationship among exercise, insulin, and cancer cell growth is unclear. We tested the hypothesis that aerobic exercise training begun during adolescence can attenuate Walker 256 tumor growth in adult rats and alter insulin secretion. Thirty-day-old male Wistar rats engaged in treadmill running for 8 weeks, 3 days/week, 44 min/day, at 55-65% VO 2max until they were 90 days old (TC, Trained Control). An equivalently aged group was kept inactive during the same period (SC, Sedentary Control). Then, half the animals of the SC and TC groups were reserved as the control condition and the other half were inoculated with Walker 256 cancer cells, yielding two additional groups (Sedentary Walker and Trained Walker). Zero mortalities were observed in tumor-bearing rats. Body weight (BW), food intake, plasma glucose, insulin levels, and peripheral insulin sensitivity were analyzed before and after tumor cell inoculation. We also evaluated tumor growth, metastasis and cachexia. Isolated pancreatic islets secretory activity was analyzed. In addition, we evaluated mechanic sensibility. Our results showed improved physical performance according to the final workload and VO 2max and reduced BW in trained rats at the end of the running protocol. Chronic adaptation to the aerobic exercise training decreased tumor weight, cachexia and metastasis and were associated with low glucose and insulin levels and high insulin sensitivity before and after tumor cell inoculation. Aerobic exercise started at young age also reduced pancreatic islet insulin content and insulin secretion in response to a glucose stimulus, without impairing islet morphology in trained rats. Walker 256 tumor-bearing sedentary rats also presented reduced pancreatic islet insulin content, without changing insulin secretion through isolated pancreatic islets. The mechanical sensitivity test indicated that aerobic exercise training

VarWalker: Personalized Mutation Network Analysis of Putative Cancer Genes from Next-Generation Sequencing Data

PubMed Central

Jia, Peilin; Zhao, Zhongming

2014-01-01

A major challenge in interpreting the large volume of mutation data identified by next-generation sequencing (NGS) is to distinguish driver mutations from neutral passenger mutations to facilitate the identification of targetable genes and new drugs. Current approaches are primarily based on mutation frequencies of single-genes, which lack the power to detect infrequently mutated driver genes and ignore functional interconnection and regulation among cancer genes. We propose a novel mutation network method, VarWalker, to prioritize driver genes in large scale cancer mutation data. VarWalker fits generalized additive models for each sample based on sample-specific mutation profiles and builds on the joint frequency of both mutation genes and their close interactors. These interactors are selected and optimized using the Random Walk with Restart algorithm in a protein-protein interaction network. We applied the method in >300 tumor genomes in two large-scale NGS benchmark datasets: 183 lung adenocarcinoma samples and 121 melanoma samples. In each cancer, we derived a consensus mutation subnetwork containing significantly enriched consensus cancer genes and cancer-related functional pathways. These cancer-specific mutation networks were then validated using independent datasets for each cancer. Importantly, VarWalker prioritizes well-known, infrequently mutated genes, which are shown to interact with highly recurrently mutated genes yet have been ignored by conventional single-gene-based approaches. Utilizing VarWalker, we demonstrated that network-assisted approaches can be effectively adapted to facilitate the detection of cancer driver genes in NGS data. PMID:24516372

VarWalker: personalized mutation network analysis of putative cancer genes from next-generation sequencing data.

PubMed

Jia, Peilin; Zhao, Zhongming

2014-02-01

A major challenge in interpreting the large volume of mutation data identified by next-generation sequencing (NGS) is to distinguish driver mutations from neutral passenger mutations to facilitate the identification of targetable genes and new drugs. Current approaches are primarily based on mutation frequencies of single-genes, which lack the power to detect infrequently mutated driver genes and ignore functional interconnection and regulation among cancer genes. We propose a novel mutation network method, VarWalker, to prioritize driver genes in large scale cancer mutation data. VarWalker fits generalized additive models for each sample based on sample-specific mutation profiles and builds on the joint frequency of both mutation genes and their close interactors. These interactors are selected and optimized using the Random Walk with Restart algorithm in a protein-protein interaction network. We applied the method in >300 tumor genomes in two large-scale NGS benchmark datasets: 183 lung adenocarcinoma samples and 121 melanoma samples. In each cancer, we derived a consensus mutation subnetwork containing significantly enriched consensus cancer genes and cancer-related functional pathways. These cancer-specific mutation networks were then validated using independent datasets for each cancer. Importantly, VarWalker prioritizes well-known, infrequently mutated genes, which are shown to interact with highly recurrently mutated genes yet have been ignored by conventional single-gene-based approaches. Utilizing VarWalker, we demonstrated that network-assisted approaches can be effectively adapted to facilitate the detection of cancer driver genes in NGS data.

STS-69 Mission Commander David M. Walker returns to KSC

NASA Technical Reports Server (NTRS)

1995-01-01

STS-69 Mission Commander David M. Walker and four fellow crew members return to KSC for a second launch try. The Space Shuttle Endeavour is scheduled for liftoff on Sept. 7 at 11:09 a.m. EDT, just about a week after the first try was scrubbed due to a faulty fuel cell.

A new species of Culcua Walker (Diptera: Stratiomyidae) from Vietnam

USDA-ARS?s Scientific Manuscript database

A new species of Culcua Walker (Diptera: Stratiomyidae), C. lingafelteri Woodley, new species, is described from northern Vietnam. It is diagnosed relative to other species using the recent revision of the genus by Rozkošný and Kozánek (2007). This is the first species of Culcua reported from Viet...

GeoFrame Walker Lane: Overview, Rationale, and Objectives

NASA Astrophysics Data System (ADS)

Stockli, D. F.

2006-12-01

GeoFrame is an integrative geologic initiative that takes a multi-dimensional view of the building and modification of the North American continent by systematic integration of geologic and geochronometric investigations and the results from unprecedented geophysical imaging as part of the Earthscope Program. The GeoFrame effort envisions these focus site investigations to entail map-scale arrays of passive source seismic receivers and associated active source seismic studies and complementary geophysics in conjunction with geologic-based synthesis and targeted studies. One of these focus sites is the Walker Lane region in eastern California and western Nevada, situated between the Basin and Range province and the unextended Sierra Nevada block. This GeoFrame focus site workshop is particularly timely given the deployment schedule of the USArray "BigFoot" array. The Walker Lane intraplate deformation zone accommodates nearly ~25% of present-day relative motion between the Pacific and North American plates and might represent an incipient plate boundary. It provides a world-class example of the present modification of continental lithosphere by the process of transcurrent faulting and rifting and offers the opportunity to seamlessly integrate surface geology, structural geology, petrology, geo- and thermochronology, and the history of the continental lithosphere with ongoing processes in the Earth's mantle. It affords opportunities to address a number of questions posed within Earthscope such as: mechanisms of strain transfer, the role of lithospheric rheology in strain localization and seismic response, the nature and timescales of transient fault behavior, and the role of magmas and fluids in deforming lithosphere. Implicit in the design and implementation of Earthscope is the recognition that progress on issues such as these requires an integrative geophysical and geological investigation of the Walker Lane. As such, it will open new avenues of collaboration and

Effects of aquatic walking exercise using a walker in a chronic stroke patient.

PubMed

Matsuda, Tadashi; Akezaki, Yoshiteru

2017-07-01

[Purpose] The aim of this study was to examine the usefulness of aquatic walking exercise using a walker for chronic stroke patients. We also examined the psychological effects on the study subject and the primary caregiver before and after aquatic walking exercise. [Subject and Methods] The subject was a 60-year-old male with bilateral paralysis after a cerebrovascular accident. The Fugl-Meyer Assessment (FMA) total score was 116 on the right and 115 on the left. The intervention combined aquatic and land walking exercise. A U-shaped walker was used for both water and land exercise. Continuous walking distance was the measure used to evaluate land walking ability. The psychological effects on the study subject and the primary caregiver were examined with the questionnaire. [Results] In aquatic walking, the mean time to walk 5 m showed an increase from the intervention after two months. After the aquatic walking and land walking combination, continuous walking distance also showed a prolonged trend. In the survey given to the main caregivers, improvements were observed. [Conclusion] Aquatic walking practice using a walker improved motivation in a chronic stroke patient, leading to improved walking ability, with a positive psychological influence on the participant and family caregiver.

Effects of aquatic walking exercise using a walker in a chronic stroke patient

PubMed Central

Matsuda, Tadashi; Akezaki, Yoshiteru

2017-01-01

[Purpose] The aim of this study was to examine the usefulness of aquatic walking exercise using a walker for chronic stroke patients. We also examined the psychological effects on the study subject and the primary caregiver before and after aquatic walking exercise. [Subject and Methods] The subject was a 60-year-old male with bilateral paralysis after a cerebrovascular accident. The Fugl-Meyer Assessment (FMA) total score was 116 on the right and 115 on the left. The intervention combined aquatic and land walking exercise. A U-shaped walker was used for both water and land exercise. Continuous walking distance was the measure used to evaluate land walking ability. The psychological effects on the study subject and the primary caregiver were examined with the questionnaire. [Results] In aquatic walking, the mean time to walk 5 m showed an increase from the intervention after two months. After the aquatic walking and land walking combination, continuous walking distance also showed a prolonged trend. In the survey given to the main caregivers, improvements were observed. [Conclusion] Aquatic walking practice using a walker improved motivation in a chronic stroke patient, leading to improved walking ability, with a positive psychological influence on the participant and family caregiver. PMID:28744062

Simple autonomous Mars walker

NASA Technical Reports Server (NTRS)

Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

1989-01-01

Under a contract with NASA's Jet Propulsion Laboratory, Martin Marietta has developed several alternative rover concepts for unmanned exploration of the planet Mars. One of those concepts, the 'Walking Beam', is the subject of this paper. This concept was developed with the goal of achieving many of the capabilities of more sophisticated articulated-leg walkers with a much simpler, more robust, less computationally demanding and more power efficient design. It consists of two large-base tripods nested one within the other which alternately translate with respect to each other along a 5-meter beam to propel the vehicle. The semiautonomous navigation system relies on terrain geometry sensors and tacticle feedback from each foot to autonomously select a path which avoids hazards along a route designated from earth. Both mobility and navigation features of this concept are discussed including a top-level description of the vehicle's physical characteristics, deployment strategy, mobility elements, sensor suite, theory of operation, navigation and control processes, and estimated performance.

Women in History--Madame C. J. Walker 1867-1919

ERIC Educational Resources Information Center

Huber, Germaine W.

2009-01-01

This article profiles Madame C. J. Walker. Sarah Breedlove was born on December 23, 1867, the fifth of six children of Owen and Minerva Breedlove. Sarah was the first of the Breedlove children to be born after the end of slavery. Her parents died when she was six or seven years of age. At age fourteen she married Moses McWilliams, who also died in…

Upper-Ocean Heat Balance Processes and the Walker Circulation in CMIP5 Model Projections

NASA Technical Reports Server (NTRS)

Robertson, F. R.; Roberts, J. B.; Funk, C.; Lyon, B.; Ricciardulli, L.

2012-01-01

Considerable uncertainty remains as to the importance of mechanisms governing decadal and longer variability of the Walker Circulation, its connection to the tropical climate system, and prospects for tropical climate change in the face of anthropogenic forcing. Most contemporary climate models suggest that in response to elevated CO2 and a warmer but more stratified atmosphere, the required upward mass flux in tropical convection will diminish along with the Walker component of the tropical mean circulation as well. Alternatively, there is also evidence to suggest that the shoaling and increased vertical stratification of the thermocline in the eastern Pacific will enable a muted SST increase there-- preserving or even enhancing some of the dynamical forcing for the Walker cell flow. Over the past decade there have been observational indications of an acceleration in near-surface easterlies, a strengthened Pacific zonal SST gradient, and globally-teleconnected dislocations in precipitation. But is this evidence in support of an ocean dynamical thermostat process posited to accompany anthropogenic forcing, or just residual decadal fluctuations associated with variations in warm and cold ENSO events and other stochastic forcing? From a modeling perspective we try to make headway on this question by examining zonal variations in surface energy fluxes and dynamics governing tropical upper ocean heat content evolution in the WCRP CMIP5 model projections. There is some diversity among model simulations; for example, the CCSM4 indicates net ocean warming over the IndoPacific region while the CSIRO model concentrates separate warming responses over the central Pacific and Indian Ocean regions. The models, as with observations, demonstrate strong local coupling between variations in column water vapor, downward surface longwave radiation and SST; but the spatial patterns of changes in the sign of this relationship differ among models and, for models as a whole, with

78 FR 37706 - Safety Standards for Infant Walkers and Infant Swings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-24

... Danny Keysar Child Product Safety Notification Act, if ASTM revises the underlying voluntary standard... CONSUMER PRODUCT SAFETY COMMISSION 16 CFR Parts 1216 and 1223 Safety Standards for Infant Walkers... the Danny Keysar Child Product Safety Notification Act, the U.S. Consumer Product Safety Commission...

Lightweight Biometric Sensing for Walker Classification Using Narrowband RF Links

PubMed Central

Liang, Zhuo-qian

2017-01-01

This article proposes a lightweight biometric sensing system using ubiquitous narrowband radio frequency (RF) links for path-dependent walker classification. The fluctuated received signal strength (RSS) sequence generated by human motion is used for feature representation. To capture the most discriminative characteristics of individuals, a three-layer RF sensing network is organized for building multiple sampling links at the most common heights of upper limbs, thighs, and lower legs. The optimal parameters of sensing configuration, such as the height of link location and number of fused links, are investigated to improve sensory data distinctions among subjects, and the experimental results suggest that the synergistic sensing by using multiple links can contribute a better performance. This is the new consideration of using RF links in building a biometric sensing system. In addition, two types of classification methods involving vector quantization (VQ) and hidden Markov models (HMMs) are developed and compared for closed-set walker recognition and verification. Experimental studies in indoor line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios are conducted to validate the proposed method. PMID:29206188

Lightweight Biometric Sensing for Walker Classification Using Narrowband RF Links.

PubMed

Liu, Tong; Liang, Zhuo-Qian

2017-12-05

This article proposes a lightweight biometric sensing system using ubiquitous narrowband radio frequency (RF) links for path-dependent walker classification. The fluctuated received signal strength (RSS) sequence generated by human motion is used for feature representation. To capture the most discriminative characteristics of individuals, a three-layer RF sensing network is organized for building multiple sampling links at the most common heights of upper limbs, thighs, and lower legs. The optimal parameters of sensing configuration, such as the height of link location and number of fused links, are investigated to improve sensory data distinctions among subjects, and the experimental results suggest that the synergistic sensing by using multiple links can contribute a better performance. This is the new consideration of using RF links in building a biometric sensing system. In addition, two types of classification methods involving vector quantization (VQ) and hidden Markov models (HMMs) are developed and compared for closed-set walker recognition and verification. Experimental studies in indoor line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios are conducted to validate the proposed method.

78 FR 25234 - Proposed Establishment of Class E Airspace; Walker, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-30

... accommodate new Standard Instrument Approach Procedures (SIAP) at Walker Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs... on this proposal to the U.S. Department of Transportation, Docket Operations, 1200 New Jersey Avenue...

Walker Branch Watershed: Temperature Response of Organic-Matter Decomposition in Headwater Stream

DOE Data Explorer

Griffiths, Natalie A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Tiegs, Scott D. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2016-01-01

This data set reports the results of a field study investigating the effect of temperature on organic-matter decomposition in the West Fork of Walker Branch (Figure 1), a headwater stream on the Oak Ridge Reservation in east Tennessee.

Epiphanic Awakenings in Raymond Carver's "Cathedral" and Alice Walker's "Everyday Use"

ERIC Educational Resources Information Center

Sadeq, Ala Eddin; Al-Badawi, Mohammed

2016-01-01

This paper explores how two short stories from very different backgrounds conclude in a significant epiphany for the characters. Raymond Carver's short story "Cathedral" and Alice Walker's "Everyday Use" are studied to see how the husband in Carver's work is blinder than his visually-impaired overnight guest, and the…

Intelligent walkers for the elderly: performance and safety testing of VA-PAMAID robotic walker.

PubMed

Rentschler, Andrew J; Cooper, Rory A; Blasch, Bruce; Boninger, Michael L

2003-01-01

A walker that could help navigate and avoid collisions with obstacles could help reduce health costs and increase the quality of care and independence of thousands of people. This study evaluated the safety and performance of the Veterans Affairs Personal Adaptive Mobility Aid (VA-PAMAID). We performed engineering tests on the VA-PAMAID to determine safety factors, including stability, energy consumption, fatigue life, and sensor and control malfunctions. The VA-PAMAID traveled 10.9 km on a full charge and avoided obstacles while traveling at a speed of up to 1.2 m/s. No failures occurred during static stability, climatic, or fatigue testing. Some problems were encountered during obstacle climbing and sensor and control testing. The VA-PAMAID has good range, has adequate reaction time, and is structurally sound. Clinical trials are planned to compare the device to other low-technical adaptive mobility devices.

Comparison of geologically-averaged paleomagnetic and "instantaneous" GPS rotation data in the West-Central Walker Lane

NASA Astrophysics Data System (ADS)

Farner, M. J.; Pluhar, C. J.; Carlson, C. W.

2011-12-01

The Walker Lane belt is a highly tectonically active region of dextral shear in western North America. Situated between the margins of the Sierra Nevada microplate and the Basin and Range extension, it extends northward from the Garlock Fault into portions of Southern Oregon. The Walker Lane is characterized by dextral shear accommodated by strike slip faults and left-stepping normal faults (Unruh et al, 2003). Faulting in the Walker Lane accounts for approximately 25% of the relative motion between the North American and Pacific Plates (Reheis and Dixon 1996). The study spans a region where the Sierra Nevada microplate has shed fault-bounded blocks from its eastern margin into the central Walker Lane during the Neogene. These blocks have behaved somewhat independently of one another and the Sierra Nevada as evidenced by spatially-variable magnitudes of vertical-axis rotation. This blurs the boundary of definition between microplate and fault block. One of the key questions regarding Walker Lane deformation is what is the role of rotation with respect to fault blocks and at what rate(s) does rotation occur. The software package SSPX (Cardozo and Allmendinger 2009) is used to examine previously published geodetic data to derive rotation rates in the west-central Walker Lane. A rate of 1.70° ± 0.24°/Ma is determined for Bridgeport Valley, CA based upon strain inversion of the locally-sparse GPS station data in SSPX. This rate is consistent with paleomagnetically-determined rotation rates for ~9.4 Ma members of the Stanislaus Group around Bridgeport Valley, adjacent to the Mina Deflection (e.g. King et al, 2007 and our data). However there are several shortcomings to using currently available GPS data for this purpose. GPS station spacing in many places does not provide spatial resolution of rotation comparable to the paleomagnetic dataset, which in turn limits our ability to examine small lithospheric fault blocks geodetically. The paleomagnetic data shows

The Dirac equation and the normalization of its solutions in a closed Friedmann- Robertson-Walker universe

NASA Astrophysics Data System (ADS)

Finster, Felix; Reintjes, Moritz

2009-05-01

We set up the Dirac equation in a Friedmann-Robertson-Walker geometry and separate the spatial and time variables. In the case of a closed universe, the spatial dependence is solved explicitly, giving rise to a discrete set of solutions. We compute the probability integral and analyze a spacetime normalization integral. This analysis allows us to introduce the fermionic projector in a closed Friedmann-Robertson-Walker geometry and to specify its global normalization as well as its local form. First author supported in part by the Deutsche Forschungsgemeinschaft.

Genetic, chromosomal, and syndromic causes of neural tube defects

PubMed Central

Seidahmed, Mohammed Z.; Abdelbasit, Omer B.; Shaheed, Meeralebbae M.; Alhussein, Khalid A.; Miqdad, Abeer M.; Samadi, Abdulmohsen S.; Khalil, Mohammed I.; Al-Mardawi, Elham; Salih, Mustafa A.

2014-01-01

Objective: To ascertain the incidence, and describe the various forms of neural tube defects (NTDs) due to genetic, chromosomal, and syndromic causes. Methods: We carried out a retrospective analysis of data retrieved from the medical records of newborn infants admitted to the Neonatal Intensive Care Unit with NTDs and their mothers spanning 14 years (1996-2009) at the Security Forces Hospital, Riyadh, Saudi Arabia. The cases were ascertained by a perinatologist, neonatologist, geneticist, radiologist, and neurologist. The literature was reviewed via a MEDLINE search. Only liveborn babies were included. Permission from the Educational Committee at the Security Forces Hospital was obtained prior to the collection of data. Results: Out of 103 infants with NTDs admitted during this period, 20 (19.4%) were found to have an underlying genetic syndromic, chromosomal and/or other anomalies. There were 5 cases of Meckel-Gruber syndrome, 2 Joubert syndrome, one Waardenburg syndrome, one Walker-Warburg syndrome, 2 chromosomal disorders, 2 caudal regression, one amniotic band disruption sequence, one associated with omphalocele, one with diaphragmatic hernia, and 4 with multiple congenital anomalies. Conclusions: There is a high rate of underlying genetic syndromic and/or chromosomal causes of NTDs in the Saudi Arabian population due to the high consanguinity rate. Identification of such association can lead to more accurate provisions of genetic counseling to the family including preimplantation genetic diagnosis or early termination of pregnancies associated with lethal conditions. PMID:25551112

21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cane, crutch, and walker tips and pads. 890.3790 Section 890.3790 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane...

21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cane, crutch, and walker tips and pads. 890.3790 Section 890.3790 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane...

21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cane, crutch, and walker tips and pads. 890.3790 Section 890.3790 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane...

21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cane, crutch, and walker tips and pads. 890.3790 Section 890.3790 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane...

21 CFR 890.3790 - Cane, crutch, and walker tips and pads.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cane, crutch, and walker tips and pads. 890.3790 Section 890.3790 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3790 Cane...

X-15 #2 with test pilot Joe Walker

NASA Technical Reports Server (NTRS)

1961-01-01

Joe Walker is seen here after a flight in front of the X-15 #2 (56-6671) rocket-powered research aircraft. Joseph A. Walker was a Chief Research Pilot at the NASA Dryden Flight Research Center during the mid-1960s. He joined NACA in March 1945, and served as project pilot at the Edwards flight research facility on such pioneering research projects as the D-558-1, D-558-2, X-1, X-3, X-4, X-5, and the X-15. He also flew programs involving the F-100, F-101, F-102, F-104, and the B-47. Walker made the first NASA X-15 flight on March 25, 1960. He flew the research aircraft 24 times and achieved its highest altitude. He attained a speed of 4,104 mph (Mach 5.92) during a flight on June 27, 1962, and reached an altitude of 354,200 feet (67.08 miles) on August 22, 1963 (his last X-15 flight). This was one of three flights by Walker that achieved altitudes over 50 miles. Walker was killed on June 8, 1966, when his F-104 collided with the XB-70. The X-15 was a rocket-powered aircraft 50 ft long with a wingspan of 22 ft. It was a missile-shaped vehicle with an unusual wedge-shaped vertical tail, thin stubby wings, and unique fairings that extended along the side of the fuselage. The X-15 weighed about 14,000 lb empty and approximately 34,000 lb at launch. The XLR-99 rocket engine, manufactured by Thiokol Chemical Corp., was pilot controlled and was capable of developing 57,000 lb of rated thrust (actual thrust reportedly climbed to 60,000 lb). North American Aviation built three X-15 aircraft for the program. The X-15 research aircraft was developed to provide in-flight information and data on aerodynamics, structures, flight controls, and the physiological aspects of high-speed, high-altitude flight. A follow-on program used the aircraft as a testbed to carry various scientific experiments beyond the Earth's atmosphere on a repeated basis. For flight in the dense air of the usable atmosphere, the X-15 used conventional aerodynamic controls such as rudder surfaces on the

ARG-walker: inference of individual specific strengths of meiotic recombination hotspots by population genomics analysis.

PubMed

Chen, Hao; Yang, Peng; Guo, Jing; Kwoh, Chee Keong; Przytycka, Teresa M; Zheng, Jie

2015-01-01

Meiotic recombination hotspots play important roles in various aspects of genomics, but the underlying mechanisms for regulating the locations and strengths of recombination hotspots are not yet fully revealed. Most existing algorithms for estimating recombination rates from sequence polymorphism data can only output average recombination rates of a population, although there is evidence for the heterogeneity in recombination rates among individuals. For genome-wide association studies (GWAS) of recombination hotspots, an efficient algorithm that estimates the individualized strengths of recombination hotspots is highly desirable. In this work, we propose a novel graph mining algorithm named ARG-walker, based on random walks on ancestral recombination graphs (ARG), to estimate individual-specific recombination hotspot strengths. Extensive simulations demonstrate that ARG-walker is able to distinguish the hot allele of a recombination hotspot from the cold allele. Integrated with output of ARG-walker, we performed GWAS on the phased haplotype data of the 22 autosome chromosomes of the HapMap Asian population samples of Chinese and Japanese (JPT+CHB). Significant cis-regulatory signals have been detected, which is corroborated by the enrichment of the well-known 13-mer motif CCNCCNTNNCCNC of PRDM9 protein. Moreover, two new DNA motifs have been identified in the flanking regions of the significantly associated SNPs (single nucleotide polymorphisms), which are likely to be new cis-regulatory elements of meiotic recombination hotspots of the human genome. Our results on both simulated and real data suggest that ARG-walker is a promising new method for estimating the individual recombination variations. In the future, it could be used to uncover the mechanisms of recombination regulation and human diseases related with recombination hotspots.

Draft Title V Operating Permit: Andeavor Field Services, LLC - Walker Hollow Compressor Station

EPA Pesticide Factsheets

Draft Title V Operating Permit, statement of basis, public notice bulletin, and the administrative permit docket (application and other supporting documents) for the Draft Part 71 Permit for Andeavor Field Services, LLC - Walker Hollow CS.

Optimal recruitment strategies for groups of interacting walkers with leaders

NASA Astrophysics Data System (ADS)

Martínez-García, Ricardo; López, Cristóbal; Vazquez, Federico

2015-02-01

We introduce a model of interacting random walkers on a finite one-dimensional chain with absorbing boundaries or targets at the ends. Walkers are of two types: informed particles that move ballistically towards a given target and diffusing uninformed particles that are biased towards close informed individuals. This model mimics the dynamics of hierarchical groups of animals, where an informed individual tries to persuade and lead the movement of its conspecifics. We characterize the success of this persuasion by the first-passage probability of the uninformed particle to the target, and we interpret the speed of the informed particle as a strategic parameter that the particle can tune to maximize its success. We find that the success probability is nonmonotonic, reaching its maximum at an intermediate speed whose value increases with the diffusing rate of the uninformed particle. When two different groups of informed leaders traveling in opposite directions compete, usually the largest group is the most successful. However, the minority can reverse this situation and become the most probable winner by following two different strategies: increasing its attraction strength or adjusting its speed to an optimal value relative to the majority's speed.

The key role of ozone depleting substances in weakening the Walker Circulation over the second half of the 20th Century

NASA Astrophysics Data System (ADS)

Bellomo, K.; Polvani, L. M.

2017-12-01

It is widely believed that the Walker Circulation will weaken in response to increasing greenhouse gases (GHG) by the end of the 21st century. But over the 20th century, the existence of a statistical significant weakening trends in the observations remains unclear. We here present new modelling evidence showing that Ozone Depleting Substances (ODS) may have significantly contributed to the weakening of the Walker Circulation over the years 1955-2005. While the primary impact of increasing ODS has been the formation of the ozone hole, it is perhaps not as widely appreciated that ODS are also powerful greenhouse gases. Using an ensemble of integrations with the the Whole Atmosphere Chemistry Climate Model, we show that the surface warming caused by increasing ODS over the second half of the 20th century causes a statistically significant weakening of the Walker Circulation in the model. In fact, we find that the increase of the other well-mixed GHG alone leads to a strengthening, not a weakening of the Walker Circulation, over that period in our model. When ODS concentrations are held fixed at 1950's levels, the effect of the other GHG is not sufficient, and a warming delay in the eastern tropical Pacific SST leads to an increase in the east-west SST gradient which is accompanied by a strengthening of the Walker Circulation. But, when the forcing from ODS is added in, the additional radiative forcing causes the eastern Pacific to warm faster, and the trend in the Walker Circulation reverses sign and becomes negative over the second half of the 20th century.

Analog Landau-He-McKellar-Wilkens quantization due to noninertial effects of the Fermi-Walker reference frame

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakke, Knut

2010-05-15

We will show that when a neutral particle with permanent electric dipole moment interacts with a specific field configuration when the local reference frames of the observers are Fermi-Walker transported, the Landau quantization analog to the He-McKellar-Wilkens setup arises in the nonrelativistic quantum dynamics of the neutral particle due the noninertial effects of the Fermi-Walker reference frame. We show that the noninertial effects do not break the infinity degeneracy of the energy levels, but in this case, the cyclotron frequency depends on the angular velocity.

1. EXTERIOR VIEW OF ELM CITY PLANT (A. FRANCIS WALKER, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. EXTERIOR VIEW OF ELM CITY PLANT (A. FRANCIS WALKER, 1905-07) FROM SECOND AVENUE ON OPPOSITE SIDE OF ENTRANCE. THIS STRUCTURE WAS ORIGINALLY BUILT AS THE ELM CITY COTTON MILL OF CALLAWAY MILLS. NOTE RESERVOIR IN FOREGROUND. THIS PHOTOGRAPH IS THE LEFT SIDE OF A PANORAMA VIEW THAT INCLUDES HAER Nos. GA-128-2 AND GA-128-3. - Elm City Cotton Mill, 1000 Elm Street, La Grange, Troup County, GA

Do Canes or Walkers Make Any Difference? NonUse and Fall Injuries.

PubMed

Luz, Clare; Bush, Tamara; Shen, Xiaoxi

2017-04-01

Examine patterns of cane and walker use as related to falls and fall injuries. Among people who fall at home, most do not have an assistive device with them when they fall. Nonusers who fall sustain more severe injuries. This was a cross-sectional study using a self-administered written survey completed by 262 people aged 60 and older who were community dwelling, cognitively intact, and current cane/walker users with a history of falls. They were recruited through clinical practice sites, churches, and senior housing in central Michigan. Outcomes of interest included patterns of device use, reasons for nonuse, device use at time of fall, and fall-related injuries. Seventy-five percent of respondents who fell were not using their device at the time of fall despite stating that canes help prevent falls. Reasons for nonuse included believing it was not needed, forgetfulness, the device made them feel old, and inaccessibility. Perceived risk was not high enough to engage in self-protective behavior. However, nonuse led to a significantly higher proportion of falls resulting in surgery than among device users. Among respondents requiring surgery, 100% were nonusers. Most respondents never received a home safety evaluation (68%) and only 50% received training on proper device use. Providers must place increased emphasis on the importance of cane/walker use for injury prevention through patient education to promote personal relevance, proper fitting, and training. New strategies are needed to improve device acceptability and accessibility. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A 'water walkers' exercise program for the elderly.

PubMed

Heyneman, C A; Premo, D E

1992-01-01

Recent studies have shown that older people, stereotyped as weak, frail, and inactive, demonstrate an equal capacity to reap the physical and psychological benefits of recreational exercise. A low cost aquatic exercise program is proposed that is geared towards those persons who, because of their physical limitations, are unable to participate in the more traditional walking or low-impact aerobics programs currently available for seniors. A water-based program would allow these people to gain all the advantages of land-based exercise with out stress or strain on arthritic joints. In addition, the use of water walkers (a buoyancy device which attaches easily around the waist) would allow total freedom of movement without fear of deep water. Those with various levels of disability could, therefore, participate at their own pace. Two programs, including transportation, would be provided twice a week for 8 weeks each. An individual 45-minute session would consist of a warm-up period with gentle stretching, a cardiovascular segment, a cool-down period, strength-training, and a final stretching time. All exercises would be conducted with participants wearing the water walkers, allowing total immersion to the shoulder. Free to move about the pool, they would be encouraged to interact socially with one another. The results of the program would be determined by measuring range of motion, cardiovascular endurance, and strength before and after each 8-week session. Participants' level of self confidence and life satisfaction will be estimated and any psychological improvement will be documented.

High Performance Sustainable School Design: Roy Lee Walker Elementary, McKinney, Texas.

ERIC Educational Resources Information Center

SHW Group, Inc., Dallas, TX.

This document describes the sustainable features of the Roy Lee Walker Elementary School (Texas), a prototype "Eco Education" school that blends the physical environment with the student learning process while protecting the site. The document also presents the process of integrating sustainability criteria in all phases of the school's…

How do walkers behave when crossing the way of a mobile robot that replicates human interaction rules?

PubMed

Vassallo, Christian; Olivier, Anne-Hélène; Souères, Philippe; Crétual, Armel; Stasse, Olivier; Pettré, Julien

2018-02-01

Previous studies showed the existence of implicit interaction rules shared by human walkers when crossing each other. Especially, each walker contributes to the collision avoidance task and the crossing order, as set at the beginning, is preserved along the interaction. This order determines the adaptation strategy: the first arrived increases his/her advance by slightly accelerating and changing his/her heading, whereas the second one slows down and moves in the opposite direction. In this study, we analyzed the behavior of human walkers crossing the trajectory of a mobile robot that was programmed to reproduce this human avoidance strategy. In contrast with a previous study, which showed that humans mostly prefer to give the way to a non-reactive robot, we observed similar behaviors between human-human avoidance and human-robot avoidance when the robot replicates the human interaction rules. We discuss this result in relation with the importance of controlling robots in a human-like way in order to ease their cohabitation with humans. Copyright © 2017 Elsevier B.V. All rights reserved.

STS-30 Commander David M. Walker during preflight press conference at JSC

NASA Technical Reports Server (NTRS)

1989-01-01

During preflight press conference, STS-30 Commander David M. Walker monitors a question from a news media representative. The event was held in the JSC Auditorium and Public Affairs Facility Bldg 2 briefing room. STS-30 mission will fly onboard Atlantis, Orbiter Vehicle (OV) 104, and is scheduled for an April 28 liftoff.

Collateral Damage: Veterans and Domestic Violence in Mari Sandoz's "The Tom-Walker"

ERIC Educational Resources Information Center

Bahr, Kathy

2010-01-01

"The Tom-Walker" combines the best of Sandoz's realism with her worst attempts at moralizing. Unable to divine exactly what political configuration right-wing post-World War II sentiments might take, Sandoz nevertheless feared a fascist uprising in this country. Perhaps because these concerns dominated her thoughts at the time, she allowed her…

Behaviorial and Toxicological Studies of the Drywood Termite, Cryptotermes brevis (Walker) (Kalotermitidae: Isoptera).

DTIC Science & Technology

the insecticides dieldrin, silica aerogel , dichlorovos and sulfuryl fluoride in control of drywood termite Cryptotermes brevis (Walker). Preference...concentrations were as low as 0.25%. Effective control concentrations should be at least or above 1%. Silica aerogel acts as an effective barrier against C. brevis

Optimal search strategies of space-time coupled random walkers with finite lifetimes

NASA Astrophysics Data System (ADS)

Campos, D.; Abad, E.; Méndez, V.; Yuste, S. B.; Lindenberg, K.

2015-05-01

We present a simple paradigm for detection of an immobile target by a space-time coupled random walker with a finite lifetime. The motion of the walker is characterized by linear displacements at a fixed speed and exponentially distributed duration, interrupted by random changes in the direction of motion and resumption of motion in the new direction with the same speed. We call these walkers "mortal creepers." A mortal creeper may die at any time during its motion according to an exponential decay law characterized by a finite mean death rate ωm. While still alive, the creeper has a finite mean frequency ω of change of the direction of motion. In particular, we consider the efficiency of the target search process, characterized by the probability that the creeper will eventually detect the target. Analytic results confirmed by numerical results show that there is an ωm-dependent optimal frequency ω =ωopt that maximizes the probability of eventual target detection. We work primarily in one-dimensional (d =1 ) domains and examine the role of initial conditions and of finite domain sizes. Numerical results in d =2 domains confirm the existence of an optimal frequency of change of direction, thereby suggesting that the observed effects are robust to changes in dimensionality. In the d =1 case, explicit expressions for the probability of target detection in the long time limit are given. In the case of an infinite domain, we compute the detection probability for arbitrary times and study its early- and late-time behavior. We further consider the survival probability of the target in the presence of many independent creepers beginning their motion at the same location and at the same time. We also consider a version of the standard "target problem" in which many creepers start at random locations at the same time.

Nonmidline yolk sac tumour of the head and neck region in an infant with Dandy Walker syndrome--case report and review of literature.

PubMed

Upadhyaya, M; Oak, S N; Kulkarni, B K; Kalgutkar, A

1997-12-01

Germ cell neoplasms are among the most commonly observed tumors in the pediatric age group. However, yolk sac tumors, which form a common subtype occur rarely in the head and neck region. In this paper we share our experience of one such rare case and review the literature about this condition.

FreeWalker: a smart insole for longitudinal gait analysis.

PubMed

Wang, Baitong; Rajput, Kuldeep Singh; Tam, Wing-Kin; Tung, Anthony K H; Yang, Zhi

2015-08-01

Gait analysis is an important diagnostic measure to investigate the pattern of walking. Traditional gait analysis is generally carried out in a gait lab, with equipped force and body tracking sensors, which needs a trained medical professional to interpret the results. This procedure is tedious, expensive, and unreliable and makes it difficult to track the progress across multiple visits. In this paper, we present a smart insole called FreeWalker, which provides quantitative gait analysis outside the confinement of traditional lab, at low- cost. The insole consists of eight pressure sensors and two motion tracking sensors, i.e. 3-axis accelerometer and 3-axis gyroscope. This enables measurement of under-foot pressure distribution and motion sequences in real-time. The insole is enabled with onboard SD card as well as wireless data transmission, which help in continuous gait-cycle analysis. The data is then sent to a gateway, for analysis and interpretation of data, using a user interface where gait features are graphically displayed. We also present validation result of a subject's left foot, who was asked to perform a specific task. Experiment results show that we could achieve a data-sampling rate of over 1 KHz, transmitting data up to a distance of 20 meter and maintain a battery life of around 24 hours. Taking advantage of these features, FreeWalker can be used in various applications, like medical diagnosis, rehabilitation, sports and entertainment.

METALLOPROTEINS DURING DEVELOPMENT OF WALKER-256 CARCINOSARCOMA RESISTANT PHENOTYPE.

PubMed

Chekhun, V F; Lozovska, Yu V; Burlaka, A P; Ganusevich, I I; Shvets, Yu V; Lukianova, N Yu; Todor, I M; Demash, D V; Pavlova, A A; Naleskina, L A

2015-01-01

The study was focused on the detection of changes in serum and tumor metal-containing proteins in animals during development ofdoxorubicin-resistant phenotype in malignant cells after 12 courses of chemotherapy. We found that on every stage of resistance development there was a significant increase in content of ferritin and transferrin proteins (which take part in iron traffick and storage) in Walker-256 carc'inosarcoma tissue. We observed decreased serumferritin levels at the beginning stage of the resistance development and significant elevation of this protein levels in the cases withfully developed resistance phenotype. Transferrin content showed changes opposite to that offerritin. During the development of resistance phenotype the tumor tissue also exhibited increased 'free iron' concentration that putatively correlate with elevation of ROS generation and levels of MMP-2 and MMP-9 active forms. The tumor non-protein thiol content increases gradually as well. The serum of animals with early stages of resistance phenotype development showed high ceruloplasmin activity and its significant reduction after loss of tumor sensitivity to doxorubicin. Therefore, the development of resistance phenotype in Walker-256 carcinosarcoma is accompanied by both the deregulation of metal-containing proteins in serum and tumor tissue and by the changes in activity of antioxidant defense system. Thus, the results of this study allow us to determine the spectrum of metal-containing proteins that are involved in the development of resistant tumor phenotype and that may be targeted for methods for doxorubicin sensitivity correction therapy.

Sex differences in moral reasoning: response to Walker's (1984) conclusion that there are none.

PubMed

Baumrind, D

1986-04-01

Data from the Family Socialization and Developmental Competence Project are used to probe Walker's conclusion that there are no sex differences in moral reasoning. Ordinal and nominal nonparametric statistics result in a complex but theoretically meaningful network of relationships among sex, educational level, and Kohlberg stage score level, with the presence and direction of sex differences in stage score level dependent on educational level. The effects on stage score level of educational level and working status are also shown to differ for men and women. Reasons are considered for not accepting Walker's dismissal of studies that use (a) a pre-1983 scoring manual, or (b) fail to control for education. The problems presented to Kohlberg's theory by the significant relationship between educational and stage score levels in the general population are discussed, particularly as these apply to the postconventional level of moral reasoning.

Optimal handgrip height of four-wheeled walker on various road conditions to reduce muscular load for elderly users with steady walking.

PubMed

Takanokura, Masato

2010-03-22

A four-wheeled walker is a valuable tool for assisting elderly persons with walking. The handgrip height is one of the most important factor determining the usefulness of the walker. However, the optimal handgrip height for elderly users has not been considered from a biomechanical viewpoint. In this study, the handgrip height was optimized by a two-dimensional mechanical model to reduce muscular loads in the lower body as well as in the upper body with various road conditions during steady walking. A critical height of the handgrip existed at 48% of the body height for the user regardless of gender and body dimension. A lower handgrip relieved muscular load for stooping users with a lower standing height. The stooping user pushed the handgrip strongly in the perpendicular direction by leaning the upper body on the walker. However, upright users with a higher standing height should use a four-wheeled walker with a higher handgrip for maintaining his or her upright posture. For downhill movement, the optimal handgrip height depended on the slope angle and the friction coefficient between the road and the wheels of the walker. On a low-friction downhill such as asphalt with a steeper slope angle, the user was required to maintain an erect trunk with a higher handgrip and to press on the handgrip strongly in the perpendicular direction. Movement on a low-friction road was easier for users on a flat road and an uphill road, but it compelled distinct effort from users when moving downhill. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

An asymptotic solution to a passive biped walker model

NASA Astrophysics Data System (ADS)

Yudaev, Sergey A.; Rachinskii, Dmitrii; Sobolev, Vladimir A.

2017-02-01

We consider a simple model of a passive dynamic biped robot walker with point feet and legs without knee. The model is a switched system, which includes an inverted double pendulum. Robot’s gait and its stability depend on parameters such as the slope of the ramp, the length of robot’s legs, and the mass distribution along the legs. We present an asymptotic solution of the model. The first correction to the zero order approximation is shown to agree with the numerical solution for a limited parameter range.

New Analytical Solution of the Equilibrium Ampere's Law Using the Walker's Method: a Didactic Example

NASA Astrophysics Data System (ADS)

Sousa, A. N. Laurindo; Ojeda-González, A.; Prestes, A.; Klausner, V.; Caritá, L. A.

2018-02-01

This work aims to demonstrate the analytical solution of the Grad-Shafranov (GS) equation or generalized Ampere's law, which is important in the studies of self-consistent 2.5-D solution for current sheet structures. A detailed mathematical development is presented to obtain the generating function as shown by Walker (RSPSA 91, 410, 1915). Therefore, we study the general solution of the GS equation in terms of the Walker's generating function in details without omitting any step. The Walker's generating function g( ζ) is written in a new way as the tangent of an unspecified function K( ζ). In this trend, the general solution of the GS equation is expressed as exp(- 2Ψ) = 4| K '( ζ)|2/cos2[ K( ζ) - K( ζ ∗)]. In order to investigate whether our proposal would simplify the mathematical effort to find new generating functions, we use Harris's solution as a test, in this case K( ζ) = arctan(exp( i ζ)). In summary, one of the article purposes is to present a review of the Harris's solution. In an attempt to find a simplified solution, we propose a new way to write the GS solution using g( ζ) = tan( K( ζ)). We also present a new analytical solution to the equilibrium Ampere's law using g( ζ) = cosh( b ζ), which includes a generalization of the Harris model and presents isolated magnetic islands.

New Analytical Solution of the Equilibrium Ampere's Law Using the Walker's Method: a Didactic Example

NASA Astrophysics Data System (ADS)

Sousa, A. N. Laurindo; Ojeda-González, A.; Prestes, A.; Klausner, V.; Caritá, L. A.

2017-12-01

This work aims to demonstrate the analytical solution of the Grad-Shafranov (GS) equation or generalized Ampere's law, which is important in the studies of self-consistent 2.5-D solution for current sheet structures. A detailed mathematical development is presented to obtain the generating function as shown by Walker (RSPSA 91, 410, 1915). Therefore, we study the general solution of the GS equation in terms of the Walker's generating function in details without omitting any step. The Walker's generating function g(ζ) is written in a new way as the tangent of an unspecified function K(ζ). In this trend, the general solution of the GS equation is expressed as exp(- 2Ψ) = 4|K '(ζ)|2/cos2[K(ζ) - K(ζ ∗)]. In order to investigate whether our proposal would simplify the mathematical effort to find new generating functions, we use Harris's solution as a test, in this case K(ζ) = arctan(exp(i ζ)). In summary, one of the article purposes is to present a review of the Harris's solution. In an attempt to find a simplified solution, we propose a new way to write the GS solution using g(ζ) = tan(K(ζ)). We also present a new analytical solution to the equilibrium Ampere's law using g(ζ) = cosh(b ζ), which includes a generalization of the Harris model and presents isolated magnetic islands.

Monitoring Walker Assistive Devices: A Novel Approach Based on Load Cells and Optical Distance Measurements †

PubMed Central

Viegas, Vítor; Dias Pereira, J. M.; Postolache, Octavian; Girão, Pedro Silva

2018-01-01

This paper presents a measurement system intended to monitor the usage of walker assistive devices. The goal is to guide the user in the correct use of the device in order to prevent risky situations and maximize comfort. Two risk indicators are defined: one related to force unbalance and the other related to motor incoordination. Force unbalance is measured by load cells attached to the walker legs, while motor incoordination is estimated by synchronizing force measurements with distance data provided by an optical sensor. The measurement system is equipped with a Bluetooth link that enables local supervision on a computer or tablet. Calibration and experimental results are included in the paper. PMID:29439428

Modeling walker synchronization on the Millennium Bridge.

PubMed

Eckhardt, Bruno; Ott, Edward; Strogatz, Steven H; Abrams, Daniel M; McRobie, Allan

2007-02-01

On its opening day the London Millennium footbridge experienced unexpected large amplitude wobbling subsequent to the migration of pedestrians onto the bridge. Modeling the stepping of the pedestrians on the bridge as phase oscillators, we obtain a model for the combined dynamics of people and the bridge that is analytically tractable. It provides predictions for the phase dynamics of individual walkers and for the critical number of people for the onset of oscillations. Numerical simulations and analytical estimates reproduce the linear relation between pedestrian force and bridge velocity as observed in experiments. They allow prediction of the amplitude of bridge motion, the rate of relaxation to the synchronized state and the magnitude of the fluctuations due to a finite number of people.

STS-30 Commander Walker and Pilot Grabe during JSC preflight press conference

NASA Technical Reports Server (NTRS)

1989-01-01

During preflight press conference, STS-30 Commander David M. Walker (right) and Pilot Ronald J. Grabe ponder questions from the news media. The event was held in the JSC Auditorium and Public Affairs Facility Bldg 2 briefing room. STS-30 mission will fly onboard Atlantis, Orbiter Vehicle (OV) 104, and is scheduled for an April 28 liftoff.

A Linguistic Analysis of Rhetorical Strategies in Selected Narratives of Alice Walker

ERIC Educational Resources Information Center

Matunda, Robert Stephen Mokaya

2009-01-01

The objective of this investigation was to analyze rhetorical strategies of Alice Walker in four narratives, namely, "The Color Purple, In Search of Our Mother's Gardens, Possessing the Secret of Joy, and Now Is the Time To Open Your Heart". As such, this study helps to expand the body of investigation relating linguistics to literature and medium…

Parental Dermatoglyphics in Down's Syndrome. A Ten-year Study

PubMed Central

Priest, J. H.; Verhulst, C.; Sirkin, S.

1973-01-01

Fathers and mothers of Down's syndrome cases show dermal microsymptoms when a large series of parents are compared to the general population. A Walker dermal index score in the overlap range (-2·99 to +3·00) is more likely to occur in fathers of age-dependent Down's syndrome cases (mean paternal age 40, range 25 to 54 years) and in Down's syndrome mothers than in the general population. The relative risk for these fathers to have a dermal index in the overlap range is two times the risk for male controls; the corresponding risk for mothers of Down's syndrome cases is 1·6 times that for female controls. Thus a score in the overlap range may be used to indicate a group of parents at higher risk for recurrence and occurrence of trisomy 21 offspring. This higher risk parent group can be offered cytogenetic studies, including amniocentesis and chromosome analysis on peripheral blood and skin, as dictated by clinical circumstances. From a comparison of dermal indexes in these studies, the contribution of maternal mosaicism to all cases of Down's syndrome is estimated to be about 11% and the contribution of paternal mosaicism about 8%. The contribution from mosaicism in the father but not in the mother appears to increase with parental age. To confirm these estimates, more parents with trisomy 21 mosaicism and trisomy 21 offspring must be diagnosed and studied quantitatively for dermal microsymptoms. PMID:4272738

Screening optimal substrates from Erhai lakeside for Ottelia acuminata (Gagnep.) Dandy, an endangered submerged macrophyte in China.

PubMed

Chen, Shuqin; Chu, Zhaosheng; Zhou, Yunqiao; Li, Qifeng; Wang, Tieyu

2018-05-08

Because of the unstable hydrodynamic conditions in the wild, the endangered aquatic plant should be cultivated first in constructed wetlands for the protection and expansion of germplasm resources. Ottelia acuminata (Gagnep.) Dandy has become extinct in Erhai Lake, Yunnan province, China. In order to optimize substrates for this species to artificial cultivation, the native substrate (sandy soils) and the other three representative ones (red paddy soils, alluvial paddy soils, and purple paddy soils) collected from Erhai lakeside were applied to cultivate O. acuminata for 50 days. Multi indicators, such as antioxidant enzymes activity, malondialdehyde and chlorophyll-α concentration, and relative growth rate of O. acuminata, were discussed and statistically analyzed to classify the substrates. The results suggested that even disregarding the physiology significance of these indicators, hierarchical clustering analysis had high efficiency on optimizing substrates. Although various single indexes suggested different optimal substrates for macrophyte growth, red paddy soil was never excluded out the optimal substrate classes. Further study is needed to assess the substrates optimization functionalities of these indicators. This study offers amounts of physiology data and an effective method to optimize substrates of O. acuminata. It is helpful for environmental scientists and ecological engineers to conduct the similar study on endangered species.

Development rate, consumption, and host fidelity of Neostauropus alternus (Walker, 1855) Lepidoptera: Notodontidae

USDA-ARS?s Scientific Manuscript database

The Asian shrub Rhodomyrtus tomentosa is an invasive weed in Florida and Hawaii, USA. Surveys for natural enemies of this exotic shrub in Hong Kong, China resulted in the development of a laboratory colony and host range testing of Neostauropus alternus (Walker 1855) as a potential biological contro...

On the initial value problem for the wave equation in Friedmann-Robertson-Walker space-times.

PubMed

Abbasi, Bilal; Craig, Walter

2014-09-08

The propagator W ( t 0 , t 1 )( g , h ) for the wave equation in a given space-time takes initial data ( g ( x ), h ( x )) on a Cauchy surface {( t , x ) :  t = t 0 } and evaluates the solution ( u ( t 1 , x ),∂ t u ( t 1 , x )) at other times t 1 . The Friedmann-Robertson-Walker space-times are defined for t 0 , t 1 >0, whereas for t 0 →0, there is a metric singularity. There is a spherical means representation for the general solution of the wave equation with the Friedmann-Robertson-Walker background metric in the three spatial dimensional cases of curvature K =0 and K =-1 given by S. Klainerman and P. Sarnak. We derive from the expression of their representation three results about the wave propagator for the Cauchy problem in these space-times. First, we give an elementary proof of the sharp rate of time decay of solutions with compactly supported data. Second, we observe that the sharp Huygens principle is not satisfied by solutions, unlike in the case of three-dimensional Minkowski space-time (the usual Huygens principle of finite propagation speed is satisfied, of course). Third, we show that for 0< t 0 < t the limit, [Formula: see text] exists, it is independent of h ( x ), and for all reasonable initial data g ( x ), it gives rise to a well-defined solution for all t >0 emanating from the space-time singularity at t =0. Under reflection t →- t , the Friedmann-Robertson-Walker metric gives a space-time metric for t <0 with a singular future at t =0, and the same solution formulae hold. We thus have constructed solutions u ( t , x ) of the wave equation in Friedmann-Robertson-Walker space-times which exist for all [Formula: see text] and [Formula: see text], where in conformally regularized coordinates, these solutions are continuous through the singularity t =0 of space-time, taking on specified data u (0,⋅)= g (⋅) at the singular time.

Hybridization between multi-objective genetic algorithm and support vector machine for feature selection in walker-assisted gait.

PubMed

Martins, Maria; Costa, Lino; Frizera, Anselmo; Ceres, Ramón; Santos, Cristina

2014-03-01

Walker devices are often prescribed incorrectly to patients, leading to the increase of dissatisfaction and occurrence of several problems, such as, discomfort and pain. Thus, it is necessary to objectively evaluate the effects that assisted gait can have on the gait patterns of walker users, comparatively to a non-assisted gait. A gait analysis, focusing on spatiotemporal and kinematics parameters, will be issued for this purpose. However, gait analysis yields redundant information that often is difficult to interpret. This study addresses the problem of selecting the most relevant gait features required to differentiate between assisted and non-assisted gait. For that purpose, it is presented an efficient approach that combines evolutionary techniques, based on genetic algorithms, and support vector machine algorithms, to discriminate differences between assisted and non-assisted gait with a walker with forearm supports. For comparison purposes, other classification algorithms are verified. Results with healthy subjects show that the main differences are characterized by balance and joints excursion in the sagittal plane. These results, confirmed by clinical evidence, allow concluding that this technique is an efficient feature selection approach. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Dermatoglyphic peculiarities in Down's syndrome detection of mosaicism and balanced translocation carriers.

PubMed

Rodewald, A; Zang, K D; Zankl, H; Zankl, M

1981-01-01

The combination of dermatoglyphic patterns and the number and intensity of traits characteristic for Down's syndrome can be statistically expressed by the "Walker" index and the "general" index. More than 96% of a Down's syndrome series and a control series could clearly be separated by the general index. Cytogenetic and dermatoglyphic features were studied in 17 patients with mosaic trisomy 21 and their parents. In the 17 cytogenetically diagnosed patients with mosaic Down's syndrome, a highly significant correlation was observed between the percentage of trisomic cells and the presence of traits characteristic for this syndrome in the dermatoglyphic patterns. The diagnostic problems and the value of dermatoglyphic examination in cases of mosaicism, where the trisomic cell line seems to have disappeared, is discussed. The results of our study also indicate an elevated incidence of a specific dermatoglyphic pattern combination with general index values similar to Down's syndrome in one parent in nearly 20% of Down's syndrome children. The possibility of hidden mosaicism in these parents of Down's syndrome children is discussed. Furthermore, the dermatoglyphic patterns in a large kindred with an inherited 15/21 translocation (21/41 carriers of the balanced translocation; 14/41 chromosomally normal; 6/41 mongoloid members) was analyzed. The data obtained from this translocation family and especially the values obtained in the general index indicate that some dermatoglyphic stigmata are directly associated with the D/21 translocation carrier state and can therefore be used for predicting this state.

Soils of Walker Branch Watershed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lietzke, D.A.

1994-03-01

The soil survey of Walker Branch Watershed (WBW) utilized the most up-to-date knowledge of soils, geology, and geohydrology in building the soils data base needed to reinterpret past research and to begin new research in the watershed. The soils of WBW were also compared with soils mapped elsewhere along Chestnut Ridge on the Oak Ridge Reservation to (1) establish whether knowledge obtained elsewhere could be used within the watershed, (2) determine whether there were any soils restricted to the watershed, and (3) evaluate geologic formation lateral variability. Soils, surficial geology, and geomorphology were mapped at a scale of 1:1,200 usingmore » a paper base map having 2-ft contour intervals. Most of the contours seemed to reasonably represent actual landform configurations, except for dense wooded areas. For example, the very large dolines or sinkholes were shown on the contour base map, but numerous smaller ones were not. In addition, small drainageways and gullies were often not shown. These often small but important features were located approximately as soil mapping progressed.« less

Sex Differences in Moral Reasoning: Response to Walker's (1984) Conclusion That There Are None.

ERIC Educational Resources Information Center

Baumrind, Diana

1986-01-01

Takes issue with Lawrence Walker's literature review on developmental and individual differences in moral reasoning which found no consistent evidence for sex differences in moral development. Argues instead that the source and specific nature of these differences have yet to be established. (HOD)

Walker occupancy has an impact on changing airborne bacterial communities in an underground pedestrian space, as small-dust particles increased with raising both temperature and humidity.

PubMed

Okubo, Torahiko; Osaki, Takako; Nozaki, Eriko; Uemura, Akira; Sakai, Kouhei; Matushita, Mizue; Matsuo, Junji; Nakamura, Shinji; Kamiya, Shigeru; Yamaguchi, Hiroyuki

2017-01-01

Although human occupancy is a source of airborne bacteria, the role of walkers on bacterial communities in built environments is poorly understood. Therefore, we visualized the impact of walker occupancy combined with other factors (temperature, humidity, atmospheric pressure, dust particles) on airborne bacterial features in the Sapporo underground pedestrian space in Sapporo, Japan. Air samples (n = 18; 4,800L/each sample) were collected at 8:00 h to 20:00 h on 3 days (regular sampling) and at early morning / late night (5:50 h to 7:50 h / 22:15 h to 24:45 h) on a day (baseline sampling), and the number of CFUs (colony forming units) OTUs (operational taxonomic units) and other factors were determined. The results revealed that temperature, humidity, and atmospheric pressure changed with weather. The number of walkers increased greatly in the morning and evening on each regular sampling day, although total walker numbers did not differ significantly among regular sampling days. A slight increase in small dust particles (0.3-0.5μm) was observed on the days with higher temperature regardless of regular or baseline sampling. At the period on regular sampling, CFU levels varied irregularly among days, and the OTUs of 22-phylum types were observed, with the majority being from Firmicutes or Proteobacteria (γ-), including Staphylococcus sp. derived from human individuals. The data obtained from regular samplings reveled that although no direct interaction of walker occupancy and airborne CFU and OTU features was observed upon Pearson's correlation analysis, cluster analysis indicated an obvious lineage consisting of walker occupancy, CFU numbers, OTU types, small dust particles, and seasonal factors (including temperature and humidity). Meanwhile, at the period on baseline sampling both walker and CFU numbers were similarly minimal. Taken together, the results revealed a positive correlation of walker occupancy with airborne bacteria that increased with increases in

Walker occupancy has an impact on changing airborne bacterial communities in an underground pedestrian space, as small-dust particles increased with raising both temperature and humidity

PubMed Central

Okubo, Torahiko; Osaki, Takako; Nozaki, Eriko; Uemura, Akira; Sakai, Kouhei; Matushita, Mizue; Matsuo, Junji; Nakamura, Shinji; Kamiya, Shigeru

2017-01-01

Although human occupancy is a source of airborne bacteria, the role of walkers on bacterial communities in built environments is poorly understood. Therefore, we visualized the impact of walker occupancy combined with other factors (temperature, humidity, atmospheric pressure, dust particles) on airborne bacterial features in the Sapporo underground pedestrian space in Sapporo, Japan. Air samples (n = 18; 4,800L/each sample) were collected at 8:00 h to 20:00 h on 3 days (regular sampling) and at early morning / late night (5:50 h to 7:50 h / 22:15 h to 24:45 h) on a day (baseline sampling), and the number of CFUs (colony forming units) OTUs (operational taxonomic units) and other factors were determined. The results revealed that temperature, humidity, and atmospheric pressure changed with weather. The number of walkers increased greatly in the morning and evening on each regular sampling day, although total walker numbers did not differ significantly among regular sampling days. A slight increase in small dust particles (0.3–0.5μm) was observed on the days with higher temperature regardless of regular or baseline sampling. At the period on regular sampling, CFU levels varied irregularly among days, and the OTUs of 22-phylum types were observed, with the majority being from Firmicutes or Proteobacteria (γ-), including Staphylococcus sp. derived from human individuals. The data obtained from regular samplings reveled that although no direct interaction of walker occupancy and airborne CFU and OTU features was observed upon Pearson's correlation analysis, cluster analysis indicated an obvious lineage consisting of walker occupancy, CFU numbers, OTU types, small dust particles, and seasonal factors (including temperature and humidity). Meanwhile, at the period on baseline sampling both walker and CFU numbers were similarly minimal. Taken together, the results revealed a positive correlation of walker occupancy with airborne bacteria that increased with increases

Animal models of the cancer anorexia-cachexia syndrome.

PubMed

Bennani-Baiti, Nabila; Walsh, Declan

2011-09-01

Cancer cachexia, a complex wasting syndrome, is common in palliative medicine. Animal models expand our understanding of its mechanisms. A review of cancer cachexia and anorexia animal models will help investigators make an informed choice of the study model. Cancer-anorexia cachexia animal models are numerous. No one is ideal. The choice should depend on the research question. To investigate cancer-anorexia cachexia independent of pro-inflammatory cytokine effects, the MAC16 ADK and XK1 are useful. MAC16 ADK helps study the host's tumor metabolic effects, independent of any anorexia or inflammation. XK1 is both anorectic and cachectic, but data about it is limited. All other models induce a host inflammatory response. The Walker 256 ADK and MCG 101 are best avoided due to excessive tumor growth. Since individual models do not address all aspects of the syndrome, use of a combination seems wise. Suggested combinations: MAC16-ADK (non-inflammatory and non-anorectic) with YAH-130 (inflammatory, anorectic, and cachectic), Lewis lung carcinoma (slow onset anorexia) or prostate adenocarcinoma (inflammatory, anorectic but not cachectic) with YAH-130.

Low-level wind maxima in the 1969 San Mateo and Walker Fires

Treesearch

Bill C. Ryan; George R. Ellis; Donald V. Lust

1971-01-01

The strong band of low-level winds that affected the severity of the San Mateo and Walker Fires in southern California on August 1969 was analyzed and studied. Mechanisms that could have caused or contributed to these winds and similar wind situations were evaluated and are discussed. Results show that the winds in this case were probably a product of several...

Writing a Rationale for a Controversial Common Reading Book: Alice Walker's "The Color Purple."

ERIC Educational Resources Information Center

Worthington, Pepper

1985-01-01

Offers a rationale that can be used to defend the assignment of Alice Walker's controversial novel for class reading. Indicates four issues that might evoke calls for censorship: (1) subject matter, (2) vocabulary, (3) grammar, and (4) the epistolary form of the work. (RBW)

Interinstrument Consistency of the Yamax Digi-Walker Pedometer in Elementary School-Aged Children

ERIC Educational Resources Information Center

Barfield, J. P.; Rowe, David A.; Michael, Timothy J.

2004-01-01

A pedometer is a practical, inexpensive tool used to measure physical activity. Bassett et al. (1996) found that interinstrument consistency of the Yamax Digi-Walker was higher than four other pedometers when measuring distance walked in adults. The purpose of this study was to investigate the interinstrument consistency of the Yamax pedometer in…

Inverse curvature flows in asymptotically Robertson Walker spaces

NASA Astrophysics Data System (ADS)

Kröner, Heiko

2018-04-01

In this paper we consider inverse curvature flows in a Lorentzian manifold N which is the topological product of the real numbers with a closed Riemannian manifold and equipped with a Lorentzian metric having a future singularity so that N is asymptotically Robertson Walker. The flow speeds are future directed and given by 1 / F where F is a homogeneous degree one curvature function of class (K*) of the principal curvatures, i.e. the n-th root of the Gauss curvature. We prove longtime existence of these flows and that the flow hypersurfaces converge to smooth functions when they are rescaled with a proper factor which results from the asymptotics of the metric.

Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in and near Walker River Indian Reservation, Nevada 1994-95

USGS Publications Warehouse

Thodal, Carl E.; Tuttle, Peter L.

1996-01-01

A study was begun in 1994 to determine whether the quality of irrigation drainage from the Walker River Indian Reservation, Nevada, has caused or has potential to cause harmful effects on human health or on fish and wildlife, or may adversely affect the suitability of the Walker River for other beneficial uses. Samples of water, bottom sediment, and biota were collected during June-August 1994 (during a drought year) from sites upstream from and on the Walker River Indian Reservation for analyses of trace elements. Other analyses included physical characteristics, major dissolved constituents, selected species of water-soluble nitrogen and phosphorus, and selected pesticides in bottom sediment. Water samples were collected again from four sites on the Reservation in August 1995 (during a wetterthan- average year) to provide data for comparing extreme climatic conditions. Water samples collected from the Walker River Indian Reservation in 1994 equaled or exceeded the Nevada water-quality standard or level of concern for at least one of the following: water temperature, pH, dissolved solids, unionized ammonia, phosphate, arsenic, boron, chromium, lead, and molybdenum; in 1995, only a single sample from one site exceeded a Nevada water-quality standard for molybdenum. Levels of concern for trace elements in bottom sediment collected in 1994 were equaled or exceeded for arsenic, iron, manganese, and zinc. Concentrations of organochiorine pesticide residues in bottom sediment were below analytical reporting limits. Levels of concern for trace-elements in samples of biota were equaled or exceeded for arsenic, boron, copper, and mercury. Results of toxicity testing indicate that only water samples from Walker Lake caused a toxic response in test bacteria. Arsenic and boron concentrations in water, bottom sediment, and biological tissue exceeded levels of concern throughout the Walker River Basin, but most commonly in the lower Walker River Basin. Mercury also was elevated

The world species of Balcha Walker (Hymenoptera: Chalcidoidea: Eupelmidae), parasitoids of wood-boring beetles

Treesearch

Gary A. P. Gibson

2005-01-01

The world species of Balcha Walker (Hymenoptera: Eupelmidae) are revised, keyed and illustrated. Sixteen species are recognized, including two that are newly classified in the genus, B. reticulata (Nikol?skaya) n. comb. and B. splendida (Girault) n. comb., and eight that are described as new, B. \\i>...

The Legal Dimension of RTI--Confusion Confirmed: A Response to Walker and Daves

ERIC Educational Resources Information Center

Zirkel, Perry A.

2012-01-01

In this issue of "Learning Disability Quarterly" (LDQ), Professors Daves and Walker reply to my earlier LDQ article on confusion in the cases and commentary about the legal dimension of RTI. In this brief rejoinder, I show that their reply confirms rather than resolves the confusion in their original commentary in 2010. This persistent…

Ground reaction forces of Olympic and World Championship race walkers.

PubMed

Hanley, Brian; Bissas, Athanassios

2016-01-01

Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p < .001), resulting in a flattened profile. Athletes with narrower stride widths experienced reduced peak braking forces (r = .49, p = .046), peak propulsive forces (r = .54, p = .027), peak medial forces (r = .63, p = .007) and peak vertical push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency.

Origin of the Pinenuts and Other Stories from the Walker River Paiute Reservation.

ERIC Educational Resources Information Center

George, Wuzzie; And Others

The four stories gathered from Paiute Tribal Elders through the Ethnic Heritage Studies Program have been changed from the original telling insofar as it was necessary to make them suitable to the elementary level. The short stories, meant to be spoken orally, relate how the Walker Lake Paiutes got pinenuts away from the Owyhee area ("Origin…

STS-134 crew and Expedition 24/25 crew member Shannon Walker

NASA Image and Video Library