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Sample records for isolated optic neuritis

  1. Optic neuritis

    MedlinePlus

    ... optic neuritis is unknown. The optic nerve carries visual information from your eye to the brain. The ... brain , including special images of the optic nerve Visual acuity testing Visual field testing Examination of the ...

  2. Isolated optic neuritis associated with Mycoplasma pneumoniae infection: report of two cases and literature review.

    PubMed

    Choi, Seo-Young; Choi, You-Jin; Choi, Jae-Hwan; Choi, Kwang-Dong

    2017-03-20

    Mycoplasma pneumonia is a major pathogen of primary atypical pneumonia and has been known to cause various kinds of extrapulmonary manifestations involving almost all organs of the human body. Optic neuritis associated with M. pneumoniae infection has rarely been described and mostly, it combined other neurological complications including meningitis, meningoencephalitis, myelitis, and peripheral neuropathy. We report two patients who presented with isolated optic neuritis due to M. pneumoniae infection, and reviewed the literatures on five additional patients. All patients are child or young adults, and optic neuritis was unilateral (n = 3) or bilateral (n = 4). Remarkably, four patients did not have preceding history of respiratory M. pneumonia infection, and ocular pain or headache was accompanied in only three. Although initial visual acuities were severely reduced in most cases, visual outcome was excellent after systemic steroid and/or antibiotics treatment. M. pneumonia infection should be considered in the differential diagnosis of isolated optic neuritis, especially when occurring in a child or young adults, even though there was no preceding pneumonia, accompanying ocular pain, or headache. Various mechanisms including direct local inflammation, vascular occlusion, or indirect immune modulation due to M. pneumonia infection can lead to isolated neurological manifestations without pneumonia.

  3. Optic Neuritis: Another Dickensian Diagnosis.

    PubMed

    Petzold, Axel

    2013-01-01

    The clinical diagnosis and natural history of optic neuritis was established in the late 1880s by the ophthalmologists von Graefe and Nettleship. The earlier, accurate and insightful description of transient, bilateral visual loss of Esther, the main character in the Charles Dickens novel Bleak House (1852--1853), suggests optic neuritis as a Dickensian diagnosis. Remarkably, Dickens' observations, also preceding the earliest clinical description of multiple sclerosis by Charcot in 1868, described many clinical features such as a prodromal phase; a nadir; gradual recovery over weeks; glare disability; reduced contrast sensitivity; possibly Uhthoff's phenomenon; and visual fading. All this with an accuracy that, to quote Russell Brain, "would credit a trained physician."

  4. Longitudinal Changes in Retinal Nerve Fibre Layer Thickness after an Isolated Unilateral Retrobulbar Optic Neuritis: 1-Year Results

    PubMed Central

    Yau, Gordon S. K.; Lee, Jacky W. Y.; Lau, Patrick P. K.; Tam, Victor T. Y.; Wong, Winnie W. Y.; Yuen, Can Y. F.

    2015-01-01

    Abstract The objective of this study was to investigate the longitudinal changes in retinal nerve fibre layer (RNFL) thickness 1 year after an episode of unilateral acute optic neuritis. This prospective cohort study recruited consecutive patients with a first episode of isolated, unilateral acute optic neuritis from October 2010 to June 2013. RNFL thickness of the attack and normal fellow eyes was measured by optical coherence tomography on presentation and 3, 6, and 12 months post attack in both the treatment and non-treatment groups. The treatment group consisted of subjects that opted for systemic steroids to hasten recovery time. In 20 subjects, 11 received systemic steroids and 9 were treated conservatively. The baseline RNFL thickness was similar in the attack and fellow eyes (p ≥ 0.4). Progressive RNFL thinning was seen in the attack eye over the 12-month period, with significant differences for baseline versus 3 months; baseline versus 12 months; and 3 versus 12 months (all p < 0.0001). At 12 months, the attack eye had a thinner average RNFL than the fellow eye (100.9 ± 6.1 versus 107.3 ± 5.5 µm; p = 0.002). The 12-month RNFL was similar between the treatment and non-treatment groups (p ≥ 0.6). A single episode of optic neuritis triggered an accelerated, progressive RNFL thinning up to 6 months post attack. Initial treatment with systemic steroids did not seem to alter the degree of RNFL loss at 12 months. PMID:27928326

  5. Optic neuritis in neuromyelitis optica.

    PubMed

    Levin, Marc H; Bennett, Jeffrey L; Verkman, A S

    2013-09-01

    Neuromyelitis optica (NMO) is an autoimmune demyelinating disease associated with recurrent episodes of optic neuritis and transverse myelitis, often resulting in permanent blindness and/or paralysis. The discovery of autoantibodies (AQP4-IgG) that target aquaporin-4 (AQP4) has accelerated our understanding of the cellular mechanisms driving NMO pathogenesis. AQP4 is a bidirectional water channel expressed on the plasma membranes of astrocytes, retinal Müller cells, skeletal muscle, and some epithelial cells in kidney, lung and the gastrointestinal tract. AQP4 tetramers form regular supramolecular assemblies at the cell plasma membrane called orthogonal arrays of particles. The pathological features of NMO include perivascular deposition of immunoglobulin and activated complement, loss of astrocytic AQP4, inflammatory infiltration with granulocyte and macrophage accumulation, and demyelination with axon loss. Current evidence supports a causative role of AQP4-IgG in NMO, in which binding of AQP4-IgG to AQP4 orthogonal arrays on astrocytes initiates complement-dependent and antibody-dependent cell-mediated cytotoxicity and inflammation. Immunosuppression and plasma exchange are the mainstays of therapy for NMO optic neuritis. Novel therapeutics targeting specific steps in NMO pathogenesis are entering the development pipeline, including blockers of AQP4-IgG binding to AQP4 and inhibitors of granulocyte function. However, much work remains in understanding the unique susceptibility of the optic nerves in NMO, in developing animal models of NMO optic neuritis, and in improving therapies to preserve vision.

  6. OPTIC NEURITIS IN NEUROMYELITIS OPTICA

    PubMed Central

    Levin, Marc H.; Bennett, Jeffrey L.; Verkman, A.S.

    2013-01-01

    Neuromyelitis optica (NMO) is an autoimmune demyelinating disease associated with recurrent episodes of optic neuritis and transverse myelitis, often resulting in permanent blindness and/or paralysis. The discovery of autoantibodies (AQP4-IgG) that target aquaporin-4 (AQP4) has accelerated our understanding of the cellular mechanisms driving NMO pathogenesis. AQP4 is a bidirectional water channel expressed on the plasma membranes of astrocytes, retinal Müller cells, skeletal muscle, and some epithelial cells in kidney, lung and the gastrointestinal tract. AQP4 tetramers form regular supramolecular assemblies at the cell plasma membrane called orthogonal arrays of particles. The pathological features of NMO include perivascular deposition of immunoglobulin and activated complement, loss of astrocytic AQP4, inflammatory infiltration with granulocyte and macrophage accumulation, and demyelination with axon loss. Current evidence supports a causative role of AQP4-IgG in NMO, in which binding of AQP4-IgG to AQP4 orthogonal arrays on astrocytes initiates complement-dependent and antibody-dependent cell-mediated cytotoxicity and inflammation. Immunosuppression and plasma exchange are the mainstays of therapy for NMO optic neuritis. Novel therapeutics targeting specific steps in NMO pathogenesis are entering the development pipeline, including blockers of AQP4-IgG binding to AQP4 and inhibitors of granulocyte function. However, much work remains in understanding the unique susceptibility of the optic nerves in NMO, in developing animal models of NMO optic neuritis, and in improving therapies to preserve vision. PMID:23545439

  7. Optic Neuritis: Another Dickensian Diagnosis

    PubMed Central

    Petzold, Axel

    2013-01-01

    Abstract The clinical diagnosis and natural history of optic neuritis was established in the late 1880s by the ophthalmologists von Graefe and Nettleship. The earlier, accurate and insightful description of transient, bilateral visual loss of Esther, the main character in the Charles Dickens novel Bleak House (1852--1853), suggests optic neuritis as a Dickensian diagnosis. Remarkably, Dickens’ observations, also preceding the earliest clinical description of multiple sclerosis by Charcot in 1868, described many clinical features such as a prodromal phase; a nadir; gradual recovery over weeks; glare disability; reduced contrast sensitivity; possibly Uhthoff’s phenomenon; and visual fading. All this with an accuracy that, to quote Russell Brain, “would credit a trained physician.” PMID:28167994

  8. Corticosteroids for treating optic neuritis

    PubMed Central

    Vedula, Satyanarayana S; Folse, Suzanne Brodney; Gal, Robin L; Beck, Roy

    2014-01-01

    Background Optic neuritis is an inflammatory disease of the optic nerve. It occurs more commonly in women than in men. Usually presenting with an abrupt loss of vision, recovery of vision is almost never complete. Closely linked in pathogenesis to multiple sclerosis, it may be the initial manifestation for this condition. In certain patients, no underlying cause can be found. Objectives To assess the effects of corticosteroids on visual recovery of patients with acute optic neuritis. Search strategy We searched the Cochrane Controlled Trials Register (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (issue 4, 2005), MEDLINE (1966 to December 2005), EMBASE (1980 to January 2006), NNR (issue 4, 2006), LILACS and reference lists of identified trial reports. Selection criteria We included randomized trials that evaluated corticosteroids, in any form, dose or route of administration, in people with acute optic neuritis. Data collection and analysis Two authors independently extracted the data on methodological quality and outcomes for analysis. Main results We included five randomized trials which included a total of 729 participants. Two trials evaluated low dose oral corticosteroids and two trials evaluated a higher dose of intravenous corticosteroids. One three-arm trial evaluated low-dose oral corticosteroids and high-dose intravenous corticosteroids against placebo. Trials evaluating oral corticosteroids compared varying doses of corticosteroids with placebo. Hence, we did not conduct a meta-analysis of such trials. In a meta-analysis of trials evaluating corticosteroids with total dose greater than 3000 mg administered intravenously, the relative risk of normal visual acuity with intravenous corticosteroids compared with placebo was 1.06 (95% CI 0.89 to 1.27) at six months and 1.06 (95% CI 0.92 to 1.22) at one year. The risk ratio of normal contrast sensitivity for the same comparison was 1.10 (95% CI 0.92 to 1.32) at six months follow

  9. Corticosteroids for treating optic neuritis

    PubMed Central

    Gal, Robin L; Vedula, Satyanarayana S; Beck, Roy

    2014-01-01

    Background Optic neuritis is an inflammatory disease of the optic nerve. It occurs more commonly in women than in men. Usually presenting with an abrupt loss of vision, recovery of vision is almost never complete. Closely linked in pathogenesis to multiple sclerosis, it may be the initial manifestation for this condition. In certain patients, no underlying cause can be found. Objectives To assess the effects of corticosteroids on visual recovery of patients with acute optic neuritis. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 1), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to February 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 21 February 2012. We also searched reference lists of identified trial reports to find additional trials. Selection criteria We included randomized trials that evaluated corticosteroids, in any form, dose or route of administration, in people with acute optic neuritis. Data collection and analysis Two authors independently extracted the data on methodological quality and outcomes for analysis. Main results We included six randomized trials which included a total of 750 participants. Two trials evaluated low dose oral corticosteroids while one trial evaluated low dose intravenous corticosteroids across two treatment arms and two trials evaluated a higher dose of intravenous corticosteroids. One three-arm trial evaluated low-dose oral corticosteroids and high-dose intravenous corticosteroids against placebo. Trials evaluating oral

  10. Corticosteroids for treating optic neuritis

    PubMed Central

    Gal, Robin L; Vedula, Satyanarayana S; Beck, Roy

    2016-01-01

    Background Optic neuritis is an inflammatory disease of the optic nerve. It usually presents with an abrupt loss of vision and recovery of vision is almost never complete. It occurs more commonly in women than in men. Closely linked in pathogenesis, optic neuritis may be the initial manifestation for multiple sclerosis. In some people, no underlying cause can be found. Objectives The objective of this review was to assess the effects of corticosteroids on visual recovery in eyes with acute optic neuritis. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2015, Issue 4), MEDLINE (January 1950 to April 2015), EMBASE (January 1980 to April 2015), Latin American and Caribbean Health Sciences Literature (LILACS) (January 1982 to April 2015), PubMed (January 1946 to April 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The metaRegister of Controlled Trials (mRCT) was last searched on 6 March 2014. The electronic databases were last searched on 7 April 2015. We also searched reference lists of identified trial reports for additional trials. Selection criteria We included randomized controlled trials (RCTs) that evaluated systemic corticosteroids, in any form, dose or route of administration, in people with acute optic neuritis. Data collection and analysis We used standard methodological procedures expected by Cochrane. Main results We included six RCTs with a total of 750 participants. Each trial was conducted in a different country: Denmark, Germany, India, Japan, UK, and United States. Additionally, we identified two ongoing trials not due to be completed until 2016. Among the six trials included in this review

  11. Longitudinally extensive optic neuritis in pediatric patients.

    PubMed

    Graves, Jennifer; Kraus, Verena; Soares, Bruno P; Hess, Christopher P; Waubant, Emmanuelle

    2015-01-01

    Extensive optic nerve demyelinating lesions on magnetic resonance imaging (MRI) in adults could indicate a diagnosis other than multiple sclerosis with worse prognosis such as neuromyelitis optica. We report the frequency of longitudinally extensive lesions in children with first events of optic neuritis. Subjects had brain or orbit MRI within 3 months of onset and were evaluated at the University of California, San Francisco, Pediatric Multiple Sclerosis Center. Lesion length, determined by T2 hyperintensity or contrast enhancement, was blindly graded as absent, focal or longitudinally extensive (at least 2 contiguous segments of optic nerve). Of 25 subjects, 9 (36%) had longitudinally extensive optic neuritis. Extensive lesions were not associated with non-multiple sclerosis versus multiple sclerosis diagnosis (P = 1.00). No association between age and lesion extent was observed (P = .26). Prospective studies are needed to determine if longitudinally extensive optic neuritis can predict visual outcome.

  12. Isolated new onset 'atypical' optic neuritis in the NMO clinic: serum antibodies, prognoses and diagnoses at follow-up.

    PubMed

    Piccolo, L; Woodhall, M; Tackley, G; Juryńczyk, M; Kong, Y; Domingos, J; Gore, R; Vincent, A; Waters, P; Leite, M I; Palace, J

    2016-02-01

    Severe, recurrent or bilateral optic neuritis (ON) often falls within the neuromyelitis optica spectrum disorders (NMOSD), but the diagnosis can be particularly challenging and has important treatment implications. We report the features, course and outcomes of patients presenting with atypical ON when isolated at onset. We retrospectively analyzed 69 sequential patients referred to a single UK NMO center with isolated ON at onset. Aquaporin-4 antibody (AQP4-Ab) assessment was performed in all patients and IgG1 myelin-oligodenrocyte glycoprotein (MOG-Ab) in AQP4-Ab(neg) patients. 37 AQP4-Ab positive (AQP4-Ab(pos)) and 32 AQP4-Ab negative (AQP4-Ab(neg)) patients (8 with MOG-Ab) were identified. The AQP4-Ab(neg) group included heterogeneous diagnoses: multiple sclerosis (MS), NMO, relapsing isolated ON (RION), monophasic isolated ON and relapsing acute disseminated encephalomyelitis (ADEM)-like syndromes. Compared to AQP4-Ab(neg) patients, AQP4-Ab(pos) patients had a worse residual visual outcome from first attack (median VFSS 4 vs. 0, p = 0.010) and at last assessment (median VFSS 5 versus 2, p = 0.005). However, AQP4-Ab(neg) patients with RION also had poor visual outcome. Up to 35% of AQP4-Ab(neg) patients developed a LETM and two developed low positivity for AQP4-Ab over time. Eight AQP4-Ab(neg) patients (25%) were MOG-Ab positive, covering a range of phenotypes excluding MS; the first ON attack was often bilateral and most had relapsing disease with a poor final visual outcome [VFSS 4, range (0-6)]. In conlcusion, AQP4-Ab positivity is confirmed as a predictor of poor visual outcome but AQP4-Ab(neg) RION also had a poor visual outcome. Of those without AQP4-Ab, 25% had MOG-Ab and another 25% developed MS; thus, MOG-Ab is associated with AQP4-Ab(neg) non-MS ON.

  13. [Recurrent inflammatory optic neuritis and neuromyelitis optica].

    PubMed

    de Sèze, J; Arndt, C

    2010-12-01

    Inflammatory optic neuritis (ON) represents a frequent clinical situation in neurology and ophthalmology. When MRI and CSF analysis are normal, ON is considered idiopathic with a suspected viral etiology. However, in several cases either a recurrence or a myelitis may occur. In the first case, it is relapsing inflammatory optic neuritis (RION) and in the second case it is neuromyelitis optica (NMO). Nevertheless, predictive criteria of a recurrence or an extension of the disease to spinal cord remains unknown, excepted for anti-NMO IgG antibodies which are probably highly specific for a future evolution to NMO. In the present paper, the authors successively present the two clinical situations (RION and NMO) and attempt to summarize diagnostic and prognostic criteria.

  14. Optic Nerve Sheath Meningioma Masquerading as Optic Neuritis

    PubMed Central

    Alroughani, R.; Behbehani, R.

    2016-01-01

    Optic neuritis is a common presentation of demyelinating disorders such as multiple sclerosis. It typically presents with acute painful monocular vision loss, whereas chronic optic neuropathy can be caused by compressive lesions along the anterior visual pathway, genetic, toxic, or nutritional causes. We report an unusual presentation mimicking optic neuritis, which was subsequently diagnosed as optic nerve sheath meningioma (ONSM). Misinterpretation of white matter lesions on MRI of brain and the failure to image the optic nerves at the time of acute loss of vision led to the misdiagnosis of optic neuritis in this case. A comprehensive accurate history and ordering the appropriate imaging modality remain paramount in diagnosing progressive visual deterioration. PMID:26904329

  15. Inflammatory Optic Neuritis: From Multiple Sclerosis to Neuromyelitis Optica.

    PubMed

    de Seze, Jérôme

    2013-01-01

    Inflammatory optic neuritis represents a frequent clinical situation in neurology and ophthalmology. In those parts of the world where multiple sclerosis is common, it is the condition most discussed as the cause of optic neuritis. However, the risk for conversion from optic neuritis to multiple sclerosis is evaluated at only around 50% after 15 years of follow-up. The risk is higher in cases in whom abnormalities typical of multiple sclerosis are found on magnetic resonance imaging of the brain and oligoclonal bands found on cerebrospinal fluid protein electrophoresis with no corresponding bands in serum. When these investigations are normal, optic neuritis is usually considered as "idiopathic" with a suspected viral aetiology, but in some cases, a systemic disease such as sarcoidosis, systemic lupus erythematosis, or Sjögren syndrome may be diagnosed. In rare cases, either recurrent optic neuritis or myelitis may occur without any evidence for multiple sclerosis. In the first case, it corresponds to a recently characterised disorder referred to as chronic relapsing inflammatory optic neuropathy and in the second case to a recently better identified entity, neuromyelitis optica. In the present paper, the differential diagnosis of inflammatory optic neuritis is presented from multiple sclerosis to infectious optic neuritis, systemic disease, and neuromyelitis optica.

  16. Optic Neuritis Caused by Rathke's Cleft Cyst in Young Adult

    PubMed Central

    Kobayashi, Namie; Oshitari, Toshiyuki; Kobayashi, Kentaro; Onoda, Takatsugu; Ikeda, Hidetoshi; Adachi-Usami, Emiko

    2014-01-01

    We report a case of right optic neuritis caused by Rathke's cleft cyst (RCC) in a young adult. A 15-year-old boy presented with reduced visual acuity in the right eye. He was diagnosed with optic neuritis in the right eye 4 years earlier at other clinics before he was referred to our department. During our one-year examinations, the cause of the reduced vision in his right eye could not be determined conclusively. At the age of 17 years, a RCC was detected by a neurosurgeon who specialized in hypophyseal diseases. He underwent microscopic transsphenoidal resection of the cyst, and his vision recovered to 1.2 and he has had no recurrence for at least 9 months. We suggest that repeated rupturing of the RCC was the cause of the optic neuritis, and a RCC can be successfully treated by surgery even after 3 years of optic neuritis. PMID:25045561

  17. Acute Optic Neuritis: Prognosis for the Development of Multiple Sclerosis.

    DTIC Science & Technology

    1979-12-01

    The literature was reviewed in regard to acute optic neuritis: prognosis for the development of multiple sclerosis , with specific reference to our...series, was preselected and not prospective, causing a higher incidence of later multiple sclerosis . The second factor was the definition of multiple ...development of multiple sclerosis in patients affected with acute optic neuritis. This finding leads us to conclude that an incidence of 13% to 17

  18. A case of retrobulbar optic neuritis caused by duloxetine.

    PubMed

    Bicer, Tolga; Kosker, Mustafa; Celikay, Osman; Gurdal, Canan

    2016-09-01

    Psychotropic medications may cause many ocular adverse effects including toxic optic neuropathy. We present a unique case of a 44-year-old woman using duloxetine who presented with unilateral visual loss due to retrobulbar neuritis. Physicians and patients should be alerted to this potential side effect. To the best of our knowledge, this is the first case of developing retrobulbar neuritis related to duloxetine usage.

  19. Recurrent optic neuritis associated with Chlamydia pneumoniae infection of the central nervous system.

    PubMed

    Pohl, Daniela; Rostasy, Kevin; Gieffers, Jens; Maass, Matthias; Hanefeld, Folker

    2006-09-01

    It has been suggested that Chlamydia pneumoniae (C. pneumoniae) is involved in the pathogenesis of diverse diseases of the central nervous system (CNS), including multiple sclerosis. We report the case of a 12-year-old male with isolated recurrent optic neuritis and an associated CNS infection with C. pneumoniae. The patient presented with three attacks of optic neuritis within 5 months. A positive polymerase chain reaction for C. pneumoniae in the cerebrospinal fluid led to the diagnosis of a CNS infection with C. pneumoniae. After treatment with the antibiotic rifampicin, he experienced no further attacks during the follow-up period of 6 years. These findings suggest the possibility of a C. pneumoniae infection as a contributing factor or even causative event for the development of optic neuritis.

  20. [Optic neuritis in juvenile idiopathic arthritis patient].

    PubMed

    Lourenço, Daniela M R; Buscatti, Izabel M; Lourenço, Benito; Monti, Fernanda C; Paz, José Albino; Silva, Clovis A

    2014-01-01

    Optic neuritis (ON) was rarely reported in juvenile idiopathic arthritis (JIA) patients, particularly in those under anti-tumor necrosis factor alpha blockage. However, to our knowledge, the prevalence of ON in JIA population has not been studied. Therefore, 5,793 patients were followed up at our University Hospital and 630 (11%) had JIA. One patient (0.15%) had ON and was reported herein. A 6-year-old male was diagnosed with extended oligoarticular JIA, and received naproxen and methotrexate subsequently replaced by leflunomide. At 11 years old, he was diagnosed with aseptic meningitis, followed by a partial motor seizure with secondary generalization. Brain magnetic resonance imaging (MRI) and electroencephalogram showed diffuse disorganization of the brain electric activity and leflunomide was suspended. Seven days later, the patient presented acute ocular pain, loss of acuity for color, blurred vision, photophobia, redness and short progressive visual loss in the right eye. A fundoscopic exam detected unilateral papilledema without retinal exudates. Orbital MRI suggested right ON. The anti-aquaporin 4 (anti-AQP4) antibody was negative. Pulse therapy with methylprednisolone was administered for five days, and subsequently with prednisone, he had clinical and laboratory improvement. In conclusion, a low prevalence of ON was observed in our JIA population. The absence of anti-AQP4 antibody and the normal brain MRI do not exclude the possibility of demyelinating disease associated with chronic arthritis. Therefore, rigorous follow up is required.

  1. Antibodies to Aquaporin 4, Myelin-Oligodendrocyte Glycoprotein, and the Glycine Receptor α1 Subunit in Patients With Isolated Optic Neuritis

    PubMed Central

    Martinez-Hernandez, Eugenia; Sepulveda, Maria; Rostásy, Kevin; Höftberger, Romana; Graus, Francesc; Harvey, Robert J.; Saiz, Albert; Dalmau, Josep

    2016-01-01

    IMPORTANCE In patients with isolated optic neuritis (ON), the presence of antibodies to aquaporin 4 (AQP4) has diagnostic and prognostic value. In the same clinical setting, the significance of antibodies to myelin-oligodendrocyte glycoprotein (MOG) or the glycine receptor α1 subunit (GlyR) is unclear. OBJECTIVES To investigate the frequency of antibodies to AQP4, MOG, and GlyR in patients with unilateral or bilateral, severe, or recurrent isolated ON and to determine their clinical and prognostic correlates. DESIGN, SETTING, AND PARTICIPANTS Retrospective case-control study from November 1, 2005, through May 30, 2014 with the detection of autoantibodies in a neuroimmunology referral center. We included 51 patients with ON but without clinical and magnetic resonance imaging findings outside the optic nerves and 142 controls (30 healthy individuals, 48 patients with neuromyelitis optica, and 64 patients with multiple sclerosis). MAIN OUTCOMES AND MEASURES Clinicoimmunologic analysis. We determined the presence of antibodies to AQP4, MOG, and GlyR using cell-based assays. RESULTS The median age of the patients at the onset of ON symptoms was 28 (range, 5–65) years; 36 patients (71%) were female. Antibodies were identified in 23 patients (45%), including MOG in 10 patients, AQP4 in 6 patients, and GlyR in 7 patients (concurrent with MOG in 3 and concurrent with AQP4 in 1). Patients with AQP4 antibodies (median visual score, 3.5 [range, 1–9]) had a worse visual outcome than patients with MOG antibodies alone (median visual score, 0 [range, 0–5]; P = .007), patients with seronegative findings (n = 28) (median visual score, 1.0 [range, 0–14]; P = .08), and patients with GlyR antibodies alone (n = 3) (median visual score, 0 [range, 0–2]; P = .10). The median age of the 7 patients with GlyR antibodies was 27 (range, 11–38) years; 5 (71%) of these were female. Among the 3 patients with GlyR antibodies alone, 1 patient had monophasic ON, 1 had recurrent isolated

  2. Ivermectin and onchocercal optic neuritis: short-term effects.

    PubMed

    Murdoch, I; Abiose, A; Babalola, O; Bird, A; Cousens, S; Evans, J; Jones, B

    1994-01-01

    In 1982 the macrocyclic lactone, ivermectin, was first tested in human patients with onchocerciasis. It has since undergone phase I to IV trials and is now being widely distributed in onchocercal areas. The previous microfilaricide, diethylcarbamazine citrate (DEC), is known to precipitate or exacerbate active optic neuritis in some onchocercal patients, as part of a wider inflammatory response (the Mazzotti reaction). Ivermectin may also cause a mild reaction, especially in people with high microfilarial loads. Few data are available concerning the effect of ivermectin on active optic neuritis. A large, randomised, double-masked, phase IV trial is reported. Individuals were screened for evidence of optic nerve disease (OND), and those identified as possible cases of OND underwent detailed ophthalmic examination, including fluorescein angiography, before being dosed with ivermectin or placebo. A total of 6831 persons were screened of whom 856 (13%) underwent angiography prior to dosing. At 7-14 days after dosing an attempt was made to re-examine 50% of adults over the age of 20 years, including all those with OND. Six hundred and eighty-eight repeat or new angiograms were performed. During this period, 5 new cases of active optic neuritis and one case of exacerbation of existing optic neuritis were identified. Five of these individuals had received placebo and one ivermectin. Two individuals with optic neuritis before dosing had improved after 7-14 days. One had received placebo, the other ivermectin. Ivermectin does not appear to precipitate or exacerbate optic neuritis at a period of 7-14 days.

  3. Serial Magnetization Transfer Imaging in Acute Optic Neuritis

    ERIC Educational Resources Information Center

    Hickman, S. J.; Toosy, A. T.; Jones, S. J.; Altmann, D. R.; Miszkiel, K. A.; MacManus, D. G.; Barker, G. J.; Plant, G. T.; Thompson, A. J.; Miller, D.H.

    2004-01-01

    In serial studies of multiple sclerosis lesions, reductions in magnetization transfer ratio (MTR) are thought to be due to demyelination and axonal loss, with later rises due to remyelination. This study followed serial changes in MTR in acute optic neuritis in combination with clinical and electrophysiological measurements to determine if the MTR…

  4. Oligoclonal bands predict multiple sclerosis in children with optic neuritis.

    PubMed

    Heussinger, Nicole; Kontopantelis, Evangelos; Gburek-Augustat, Janina; Jenke, Andreas; Vollrath, Gesa; Korinthenberg, Rudolf; Hofstetter, Peter; Meyer, Sascha; Brecht, Isabel; Kornek, Barbara; Herkenrath, Peter; Schimmel, Mareike; Wenner, Kirsten; Häusler, Martin; Lutz, Soeren; Karenfort, Michael; Blaschek, Astrid; Smitka, Martin; Karch, Stephanie; Piepkorn, Martin; Rostasy, Kevin; Lücke, Thomas; Weber, Peter; Trollmann, Regina; Klepper, Jörg; Häussler, Martin; Hofmann, Regina; Weissert, Robert; Merkenschlager, Andreas; Buttmann, Mathias

    2015-06-01

    We retrospectively evaluated predictors of conversion to multiple sclerosis (MS) in 357 children with isolated optic neuritis (ON) as a first demyelinating event who had a median follow-up of 4.0 years. Multiple Cox proportional-hazards regressions revealed abnormal cranial magnet resonance imaging (cMRI; hazard ratio [HR] = 5.94, 95% confidence interval [CI] = 3.39-10.39, p < 0.001), presence of cerebrospinal fluid immunoglobulin G oligoclonal bands (OCB; HR = 3.69, 95% CI = 2.32-5.86, p < 0.001), and age (HR = 1.08 per year of age, 95% CI = 1.02-1.13, p = 0.003) as independent predictors of conversion, whereas sex and laterality (unilateral vs bilateral) had no influence. Combined cMRI and OCB positivity indicated a 26.84-fold higher HR for developing MS compared to double negativity (95% CI = 12.26-58.74, p < 0.001). Accordingly, cerebrospinal fluid analysis may supplement cMRI to determine the risk of MS in children with isolated ON.

  5. Targeting Oxidative Stress for Treatment of Glaucoma and Optic Neuritis

    PubMed Central

    Kimura, Atsuko; Namekata, Kazuhiko; Guo, Xiaoli; Noro, Takahiko; Harada, Chikako

    2017-01-01

    Glaucoma is a neurodegenerative disease of the eye and it is one of the leading causes of blindness. Glaucoma is characterized by progressive degeneration of retinal ganglion cells (RGCs) and their axons, namely, the optic nerve, usually associated with elevated intraocular pressure (IOP). Current glaucoma therapies target reduction of IOP, but since RGC death is the cause of irreversible vision loss, neuroprotection may be an effective strategy for glaucoma treatment. One of the risk factors for glaucoma is increased oxidative stress, and drugs with antioxidative properties including valproic acid and spermidine, as well as inhibition of apoptosis signal-regulating kinase 1, an enzyme that is involved in oxidative stress, have been reported to prevent glaucomatous retinal degeneration in mouse models of glaucoma. Optic neuritis is a demyelinating inflammation of the optic nerve that presents with visual impairment and it is commonly associated with multiple sclerosis, a chronic demyelinating disease of the central nervous system. Although steroids are commonly used for treatment of optic neuritis, reduction of oxidative stress by approaches such as gene therapy is effective in ameliorating optic nerve demyelination in preclinical studies. In this review, we discuss oxidative stress as a therapeutic target for glaucoma and optic neuritis. PMID:28270908

  6. Optical coherence tomography segmentation reveals ganglion cell layer pathology after optic neuritis.

    PubMed

    Syc, Stephanie B; Saidha, Shiv; Newsome, Scott D; Ratchford, John N; Levy, Michael; Ford, E'tona; Crainiceanu, Ciprian M; Durbin, Mary K; Oakley, Jonathan D; Meyer, Scott A; Frohman, Elliot M; Calabresi, Peter A

    2012-02-01

    Post-mortem ganglion cell dropout has been observed in multiple sclerosis; however, longitudinal in vivo assessment of retinal neuronal layers following acute optic neuritis remains largely unexplored. Peripapillary retinal nerve fibre layer thickness, measured by optical coherence tomography, has been proposed as an outcome measure in studies of neuroprotective agents in multiple sclerosis, yet potential swelling during the acute stages of optic neuritis may confound baseline measurements. The objective of this study was to ascertain whether patients with multiple sclerosis or neuromyelitis optica develop retinal neuronal layer pathology following acute optic neuritis, and to systematically characterize such changes in vivo over time. Spectral domain optical coherence tomography imaging, including automated retinal layer segmentation, was performed serially in 20 participants during the acute phase of optic neuritis, and again 3 and 6 months later. Imaging was performed cross-sectionally in 98 multiple sclerosis participants, 22 neuromyelitis optica participants and 72 healthy controls. Neuronal thinning was observed in the ganglion cell layer of eyes affected by acute optic neuritis 3 and 6 months after onset (P < 0.001). Baseline ganglion cell layer thicknesses did not demonstrate swelling when compared with contralateral unaffected eyes, whereas peripapillary retinal nerve fibre layer oedema was observed in affected eyes (P = 0.008) and subsequently thinned over the course of this study. Ganglion cell layer thickness was lower in both participants with multiple sclerosis and participants with neuromyelitis optica, with and without a history of optic neuritis, when compared with healthy controls (P < 0.001) and correlated with visual function. Of all patient groups investigated, those with neuromyelitis optica and a history of optic neuritis exhibited the greatest reduction in ganglion cell layer thickness. Results from our in vivo longitudinal study

  7. [A case of Charles Bonnet syndrome following syphilitic optic neuritis].

    PubMed

    Ogata, Hidenori; Shigeto, Hiroshi; Torii, Takako; Kawamura, Nobutoshi; Ohyagi, Yasumasa; Kira, Jun-ichi

    2011-08-01

    Charles Bonnet syndrome refers to visual hallucinations in patients with visual acuity loss or visual field loss without dementia. We report a case of Charles Bonnet syndrome following syphilitic optic neuritis. A 62-year-old man was admitted to our hospital suffering acute bilateral visual loss in a few months. On admission, he was almost blind and his optic discs were found to be atrophic on fundoscopy. In addition to increased cell counts and protein concentration in cerebrospinal fluid (CSF), serum and CSF rapid plasma reagin tests were positive. A diagnosis of syphilitic optic neuritis was made and he was treated with intravenous penicillin G (24 million units per day for 14 days) without any recovery. After treatment finished, he began to experience complex, vivid, elaborate and colored visual hallucinations. He recognized these visions as unreal and felt distressed by them. No cognitive impairment was observed on several neuropsychological tests. We diagnosed the patient as suffering from Charles Bonnet syndrome. Brain MRI revealed diffuse mild atrophy of the cerebral cortex and multiple T2 high signal intensity lesions in the deep cerebral white matter. Single photon emission computed tomography revealed decreased regional cerebral blood flow in bilateral medial occipital lobes. Administration of olanzapine resulted in a partial remission of visual hallucinations. Charles Bonnet syndrome following syphilitic optic neuritis is rare. In the present case, visual loss and dysfunction of bilateral medial occipital lobes may have triggered the visual hallucinations, which were alleviated by olanzapine.

  8. Acute disseminated encephalomyelitis without optic neuritis followed by optic neuritis in a child due to the sudden cessation of steroid therapy.

    PubMed

    Ryu, Won Yeol; Sohn, Eun Jung; Kwon, Yoon Hyung; Jeung, Woo Jin; Ahn, Hee Bae; Park, Woo Chan; Rho, Sae Heun

    2014-01-01

    Acute disseminated encephalitis (ADEM) is an autoimmune demyelinating disorder of the central nervous system that usually occurs in children after viral infection or vaccination. It is not uncommon for ADEM to be accompanied by optic neuritis. However, ADEM followed by optic neuritis is a rare. We report the case of a 6-year-old girl who initially presented with ADEM (without optic neuritis) due to a live measles, mumps, and rubella vaccine and was treated with intravenous high-dose corticosteroids. After steroid therapy, she recovered neurologically and was not prescribed any medication, including an oral steroid taper, for use after discharge. Three weeks later, she developed unilateral optic neuritis and was again treated with steroid therapy. This is a rare case of ADEM without optic neuritis in a child, followed by optic neuritis due to the sudden cessation of steroid therapy. Further studies and follow-ups are needed to determine whether ADEM followed by optic neuritis can be considered a specific clinical form of this disorder.

  9. Optic Neuritis: From Magnocellular to Cognitive Residual Dysfunction

    PubMed Central

    Viret, Anne-Claire; Cavézian, Céline; Coubard, Olivier; Vasseur, Vivien; Raz, Noa; Levin, Netta; Vignal, Catherine; Gout, Olivier; Chokron, Sylvie

    2013-01-01

    Optic Neuritis (ON) has been associated to both parvocellular dysfunction and to an alteration of the magnocellular pathway. After objective visual field and acuity recovery, ON patients may complain about their vision suggesting a residual subclinical deficit. To better characterize visual abnormalities, 8 patients recovering from a first ON episode as well as 16 healthy controls performed a simple detection task and a more complex categorization task of images presented in low spatial frequencies (to target the magnocellular system) or in high spatial frequencies (to target the parvocellular system) or of non-filtered images. When completing the tasks with their (previously) pathologic eye, optic neuritis patients showed lower accuracy compared to controls or to their healthy eye for low spatial frequency images only. Conjointly, the longest reaction times were observed with the previously pathologic eye regardless the type of images and to a greater extent in the categorization task than in the detection task. Such data suggest two distinct, although associated, types of residual dysfunction in ON: a magnocellular pathway alteration and a more general (magno and parvocellular) visual dysfunction that could implicate the cognitive levels of visual processing. PMID:23619084

  10. Transient visually evoked potentials to sinusoidal gratings in optic neuritis.

    PubMed Central

    Plant, G T

    1983-01-01

    Transient visually evoked potentials (VEPs) to sinusoidal gratings over a range of spatial frequencies have been recorded in cases of optic neuritis. The use of the response to pattern onset in addition to the response to pattern reversal extended the range to higher spatial frequencies by up to two octaves. There was an increase in VEP delay and a greater degree of discrimination from a control group at higher spatial frequencies. This finding is discussed in the light of previous reports of luminance and checkerboard VEPs in demyelinating optic nerve disease. An attempt is made to relate amplitude changes in various VEP components to contrast sensitivity measurements in this group of patients. PMID:6663312

  11. Familial Mediterranean fever associated with optic neuritis, successfully treated with anti-interleukin 1 agents.

    PubMed

    Başaran, Özge; Kavuncu, Sevim; Güven, Alev; Uncu, Nermin; Acar-Çelikel, Banu; Çakar, Nilgün

    2016-01-01

    Familial Mediterranean fever (FMF) is an inherited periodic auto-inflammatory disease characterized by recurrent attacks of fever, synovitis and serositis. Ophthalmological manifestations of FMF are extremely rare. Here we described a boy who has been followed-up for FMF and attended with a loss of vision during the course of the disease. He was diagnosed with optic neuritis. As the other etiologies were excluded his optic neuritis was attributed to the underlying auto inflammatory process. After pulse steroid therapy, his symptoms improved and a complete remission occurred. Afterwards he had two more optic neuritis attacks. Thereafter anti-interleukin 1 (IL-1) drugs were introduced and he did not develop further attacks of both optic neuritis and FMF. This case presentation highlights the possible association between FMF and optic nerve involvement.

  12. Neuromyelitis optica-IgG (aquaporin-4) autoantibodies in immune mediated optic neuritis.

    PubMed

    Petzold, A; Pittock, S; Lennon, V; Maggiore, C; Weinshenker, B G; Plant, G T

    2010-01-01

    The clinical course of immune mediated optic neuritis (ON) will depend on the specific underlying inflammatory disease. These disorders have traditionally been classified according to clinical and MRI findings. Aquaporin-4 (AQP4) autoantibodies (neuromyelitis optica-IgG (NMO-IgG)) may have diagnostic and prognostic value in patients who present with isolated ON. In this prospective study, NMO-IgG was evaluated in 114 patients with ON in the following contexts: neuromyelitis optica (NMO), multiple sclerosis (MSON), chronic relapsing inflammatory ON (CRION), relapsing isolated ON (RION) and single isolated ON (SION). The proportion seropositive was 56% for NMO (n = 9), 0% for MSON (n = 28) and 5% for the remaining diagnostic categories (CRION (n = 19), RION (n = 17) and SION (n = 41)). Testing for NMO-IgG in patients with recurrent or severe ON who lack convincing evidence of MS may identify patients who would benefit from immunosuppression rather than MS directed immunomodulatory therapies.

  13. Optic neuritis heralding varicella zoster virus retinitis in a patient with acquired immunodeficiency syndrome.

    PubMed

    Meenken, C; van den Horn, G J; de Smet, M D; van der Meer, J T

    1998-04-01

    We report on a 29-year-old severely compromised acquired immunodeficiency syndrome patient who developed retrobulbar optic neuritis 5 weeks after an episode of cutaneous herpes zoster infection. During the optic neuritis, varicella zoster virus could be demonstrated in the cerebrospinal fluid. The neuritis responded well to treatment with foscarnet, but, 3 weeks into therapy, varicella zoster retinitis developed. Additional treatment with intravenous acyclovir stopped progression of the retinitis and resulted in healing of the retinal lesions. This case suggests that retrobulbar optic neuritis can be regarded as a prodrome of imminent acute retinal necrosis. Early recognition and prompt therapy with combined antivirals may prevent the development of this devastating ocular complication of varicella zoster infection.

  14. Optic neuritis in pediatric population: a review in current tendencies of diagnosis and management.

    PubMed

    Pérez-Cambrodí, Rafael José; Gómez-Hurtado Cubillana, Aránzazu; Merino-Suárez, María L; Piñero-Llorens, David P; Laria-Ochaita, Carlos

    2014-01-01

    Optic neuritis is an inflammation of the optic nerve and may be related to different systemic conditions. The clinical presentation of this pathology usually includes sudden loss of visual acuity (VA) which may be unilateral or bilateral, visual field restriction, pain with eye movements, dyschromatopsia, a relative afferent pupillary defect and optic disk swelling. Optic neuritis in children has specific clinical features and a better prognosis than in adulthood. Although usually appears an underlying viral disease, the main concern for practitioners is the relationship of optic neuritis with multiple sclerosis. In addition to the classical techniques as magnetic resonance imaging (MRI), current tendencies of diagnosis for eye practitioners include new imaging devices as optical coherence tomography (OCT), useful to show a thinning of the retinal fibers layer (RFL) after the inflammatory episode. Regarding the management of these patients, short-term intravenous steroid dosages seem to be the best option to treat acute attacks characterized by a very poor bilateral VA.

  15. Neuroprotective effect of melatonin in experimental optic neuritis in rats.

    PubMed

    Aranda, Marcos L; González Fleitas, María F; De Laurentiis, Andrea; Keller Sarmiento, María I; Chianelli, Mónica; Sande, Pablo H; Dorfman, Damián; Rosenstein, Ruth E

    2016-04-01

    Optic neuritis (ON) is an inflammatory, demyelinating, and neurodegenerative condition of the optic nerve, which might induce permanent vision loss. Currently, there are no effective therapies for this disorder. We have developed an experimental model of primary ON in rats through a single microinjection of 4.5 μg of bacterial lipopolysaccharide (LPS) into the optic nerve. Since melatonin acts as a pleiotropic therapeutic agent in various neurodegenerative diseases, we analyzed the effect of melatonin on LPS-induced ON. For this purpose, LPS or vehicle were injected into the optic nerve from adult male Wistar rats. One group of animals received a subcutaneous pellet of 20 mg melatonin at 24 hr before vehicle or LPS injection, and another group was submitted to a sham procedure. Melatonin completely prevented the decrease in visual evoked potentials (VEPs), and pupil light reflex (PLR), and preserved anterograde transport of cholera toxin β-subunit from the retina to the superior colliculus. Moreover, melatonin prevented microglial reactivity (ED1-immunoreactivity, P < 0.01), astrocytosis (glial fibrillary acid protein-immunostaining, P < 0.05), demyelination (luxol fast blue staining, P < 0.01), and axon (toluidine blue staining, P < 0.01) and retinal ganglion cell (Brn3a-immunoreactivity, P < 0.01) loss, induced by LPS. Melatonin completely prevented the increase in nitric oxide synthase 2, cyclooxygenase-2 levels (Western blot) and TNFα levels, and partly prevented lipid peroxidation induced by experimental ON. When the pellet of melatonin was implanted at 4 days postinjection of LPS, it completely reversed the decrease in VEPs and PLR. These data suggest that melatonin could be a promising candidate for ON treatment.

  16. A serial study of retinal changes following optic neuritis with sample size estimates for acute neuroprotection trials.

    PubMed

    Henderson, Andrew P D; Altmann, Daniel R; Trip, Anand S; Kallis, Constantinos; Jones, Steve J; Schlottmann, Patricio G; Garway-Heath, David F; Plant, Gordon T; Miller, David H

    2010-09-01

    Following an episode of optic neuritis, thinning of the retinal nerve fibre layer, which indicates axonal loss, is observed using optical coherence tomography. The longitudinal course of the retinal changes has not been well characterized. We performed a serial optical coherence tomography study in patients presenting with optic neuritis in order to define the temporal evolution of retinal nerve fibre layer changes and to estimate sample sizes for proof-of-concept trials of neuroprotection using retinal nerve fibre layer loss as the outcome measure. Twenty-three patients (7 male, 16 female, mean age 31 years) with acute clinically isolated unilateral optic neuritis were recruited to undergo optical coherence tomography, visual assessments and visual evoked potentials at presentation (median 16 days from onset of visual loss) and after 3, 6, 12 and 18 months. Compared with the clinically unaffected fellow eye, the retinal nerve fibre layer thickness of the affected eye was significantly increased at presentation and significantly reduced at all later time points. The evolution of retinal nerve fibre layer changes in the affected eye fitted well with an exponential model, with thinning appearing a mean of 1.6 months from symptom onset and the rate of ongoing retinal nerve fibre layer loss decreasing thereafter. At presentation, increased retinal nerve fibre layer thickness was associated with impaired visual acuity and prolonged visual evoked potential latency. Visual function after 12 months was not related to the extent of acute retinal nerve fibre layer swelling but was significantly associated with the extent of concurrent retinal nerve fibre layer loss. Sample size calculations for placebo-controlled trials of acute neuroprotection indicated that the numbers needed after 6 months of follow up are smaller than those after 3 months and similar to those after 12 months of follow-up. Study power was greater when investigating differences between clinically

  17. Re-evaluating the treatment of acute optic neuritis

    PubMed Central

    Bennett, Jeffrey L; Nickerson, Molly; Costello, Fiona; Sergott, Robert C; Calkwood, Jonathan C; Galetta, Steven L; Balcer, Laura J; Markowitz, Clyde E; Vartanian, Timothy; Morrow, Mark; Moster, Mark L; Taylor, Andrew W; Pace, Thaddeus W W; Frohman, Teresa; Frohman, Elliot M

    2015-01-01

    Clinical case reports and prospective trials have demonstrated a reproducible benefit of hypothalamic-pituitary-adrenal (HPA) axis modulation on the rate of recovery from acute inflammatory central nervous system (CNS) demyelination. As a result, corticosteroid preparations and adrenocorticotrophic hormones are the current mainstays of therapy for the treatment of acute optic neuritis (AON) and acute demyelination in multiple sclerosis. Despite facilitating the pace of recovery, HPA axis modulation and corticosteroids have failed to demonstrate long-term benefit on functional recovery. After AON, patients frequently report visual problems, motion perception difficulties and abnormal depth perception despite ‘normal’ (20/20) vision. In light of this disparity, the efficacy of these and other therapies for acute demyelination require re-evaluation using modern, high-precision paraclinical tools capable of monitoring tissue injury. In no arena is this more amenable than AON, where a new array of tools in retinal imaging and electrophysiology has advanced our ability to measure the anatomic and functional consequences of optic nerve injury. As a result, AON provides a unique clinical model for evaluating the treatment response of the derivative elements of acute inflammatory CNS injury: demyelination, axonal injury and neuronal degeneration. In this article, we examine current thinking on the mechanisms of immune injury in AON, discuss novel technologies for the assessment of optic nerve structure and function, and assess current and future treatment modalities. The primary aim is to develop a framework for rigorously evaluating interventions in AON and to assess their ability to preserve tissue architecture, re-establish normal physiology and restore optimal neurological function. PMID:25355373

  18. The electrophysiological examination in acute optic neuritis and during their recovery.

    PubMed

    Salu, P; Daniel, Y

    1990-01-01

    A survey of the electrophysiological methods will be given. We use this method to diagnose an optic neuritis and to evaluate it during its acute stage as well as during its recuperation. The importance of the contrast as stimulation parameter of the pattern VEP will be described, and its clinical relevance will be illustrated by a few clinical cases.

  19. Optic neuritis caused by canine distemper virus in a Jack Russell terrier.

    PubMed

    Richards, Tara R; Whelan, Nick C; Pinard, Chantale L; Alcala, Fernanda Castillo; Wolfe, Katheryn C

    2011-04-01

    An atypical case of canine distemper (CD) was diagnosed in a vaccinated healthy adult dog. The patient was presented circling, seizuring, and blind. Postmortem examination resulted in a diagnosis of CD. Optic neuritis was diagnosed, a finding not previously described in the context of CD virus infection presenting solely with neurological signs.

  20. Optic neuritis and acute anterior uveitis associated with influenza A infection: a case report

    PubMed Central

    Nakagawa, Hayate; Noma, Hidetaka; Kotake, Osamu; Motohashi, Ryosuke; Yasuda, Kanako; Shimura, Masahiko

    2017-01-01

    Background A few reports have described ocular complications of influenza A infection, such as impaired ocular movement, parasympathetic ocular nerve, keratitis, macular lesion, and frosted branch angiitis. We encountered a rare case of acute anterior uveitis and optic neuritis associated with influenza A infection. Case presentation A 70-year-old man presented with symptoms of upper respiratory tract infection. A rapid diagnostic test showed a positive result for influenza A. At the same time, he developed ocular symptoms including blurred vision with optic disk edema and hemorrhage in the left eye, and bilateral red eyes. Multiplex polymerase chain reaction performed on aqueous humor sample detected no viral infection. Visual field testing with a Goldmann perimeter showed central and paracentral scotomas in the left eye. In addition to antiviral agent (oseltamivir phosphate 75 mg), the patient was prescribed topical prednisolone acetate ophthalmic suspension eye drops every 5 hours and high-dose intravenous methylprednisolone 1,000 mg daily for 3 days. Two months later, his best-corrected visual acuity improved to 20/50 with regression of visual field defects in his left eye. Conclusion We report a case of bilateral acute anterior uveitis and unilateral optic neuritis concomitant with influenza A infection. Topical and systemic corticosteroids were effective to resolve acute anterior uveitis and neuritis. Analysis of aqueous humor sample suggested that acute anterior uveitis and optic neuritis in this case were not caused by influenza A virus infection per se but by autoimmune mechanism. PMID:28115874

  1. Aquaporin 4 antibody [NMO Ab] status in patients with severe optic neuritis in India.

    PubMed

    Ambika, Selvakumar; Balasubramanian, Mahalakshmi; Theresa, Lily; Veeraputhiran, Akila; Arjundas, Deepak

    2015-12-01

    Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system that causes attacks of optic neuritis and transverse myelitis. The discovery of a specific serum marker for NMO-IgG antibody [aquaporin 4 antibody/AQP4 Ab] has revolutionised the treatment of demyelinating diseases. Severe vision loss can be seen in optic neuritis (ON) associated with both multiple sclerosis (MS) and NMO. Identifying this antibody in optic neuritis patients can help us to establish the likelihood of these patients developing NMO (Jarius et al. Neurol Sci 298:158-162, 2010). It is important to differentiate these two entities as the treatment strategies of MS and NMO are different. To the best of our knowledge, there is no published literature regarding the importance of identifying this antibody in severe optic neuritis in Indian patients. Hence we decided to screen our severe optic neuritis patients for this AQP4 Ab. To investigate the presence of aquaporin 4 antibody and determine its prognostic value for visual and neurological outcome, in patients with bilateral and recurrent [severe] ON without any previous neurological manifestations presenting to a neuro-ophthalmology clinic in India. Single centre, prospective study. 40 patients (27 female patients and 13 male) with severe optic neuritis [patients with no visual improvement by 4 weeks from onset of vision loss] who presented either as recurrent attacks or as bilateral and severe optic neuritis between January 2010 and June 2011 were enrolled. Clinical features, visual outcome and sequential neurological events were compared between the seropositive and the seronegative groups. Aquaporin 4 antibodies were detected from serum using ELISA technique and IIF technique. Presence of this antibody in the serum was considered to be seropositive status and patients who did not have this antibody were considered seronegatives. AQP4 antibodies were detected in 8 of the 40 patients with severe ON (20 %).The

  2. Optical coherence tomography angiography in eyes with good visual acuity recovery after treatment for optic neuritis

    PubMed Central

    Higashiyama, Tomoaki; Nishida, Yasuhiro; Ohji, Masahito

    2017-01-01

    Objective To evaluate the retinal perfusion using optical coherence tomography (OCT) angiography in eyes with good visual acuity recovery after treatment for optic neuritis (ON). Methods Seven eyes of seven patients with good visual acuity recovery after treatment for monocular ON and seven eyes of each fellow eye used as controls were studied. Retinal perfusion around the disc and at the macula was evaluated using OCT angiography. The retinal nerve fiber layer thickness was measured around the disc. The ganglion cell layer complex thickness or the ganglion cell layer plus the inner plexiform layer thickness were measured at the macula. Results The retinal perfusions in all eyes with ON decreased around the disc and at the macula compared with those of the fellow eyes, as shown by OCT angiography (disc, P = 0.003; macula, P = 0.001). The retinal thicknesses in all eyes with ON also decreased around the disc and at the macula compared with those of the fellow eyes (disc, P < 0.001; macula, P = 0.003). Conclusions Optic neuritis may cause not only retinal structural damage but also decreased retinal perfusion, even after the visual acuity recovered well after treatment. PMID:28192497

  3. Serial Diffusion Tensor Imaging of the Optic Radiations after Acute Optic Neuritis

    PubMed Central

    van der Walt, Anneke; Butzkueven, Helmut; Klistorner, Alexander; Egan, Gary F.; Kilpatrick, Trevor J.

    2016-01-01

    Previous studies have reported diffusion tensor imaging (DTI) changes within the optic radiations of patients after optic neuritis (ON). We aimed to study optic radiation DTI changes over 12 months following acute ON and to study correlations between DTI parameters and damage to the optic nerve and primary visual cortex (V1). We measured DTI parameters [fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD)] from the optic radiations of 38 acute ON patients at presentation and 6 and 12 months after acute ON. In addition, we measured retinal nerve fibre layer thickness, visual evoked potential amplitude, optic radiation lesion load, and V1 thickness. At baseline, FA was reduced and RD and MD were increased compared to control. Over 12 months, FA reduced in patients at an average rate of −2.6% per annum (control = −0.51%; p = 0.006). Change in FA, RD, and MD correlated with V1 thinning over 12 months (FA: R = 0.450, p = 0.006; RD: R = −0.428, p = 0.009; MD: R = −0.365, p = 0.029). In patients with no optic radiation lesions, AD significantly correlated with RNFL thinning at 12 months (R = 0.489, p = 0.039). In conclusion, DTI can detect optic radiation changes over 12 months following acute ON that correlate with optic nerve and V1 damage. PMID:27555964

  4. Relationship between Cerebrospinal Fluid Biomarkers for Inflammation, Demyelination and Neurodegeneration in Acute Optic Neuritis

    PubMed Central

    Modvig, Signe; Degn, Matilda; Horwitz, Henrik; Cramer, Stig P.; Larsson, Henrik B. W.; Wanscher, Benedikte; Sellebjerg, Finn; Frederiksen, Jette L.

    2013-01-01

    Background Various inflammatory biomarkers show prognostic potential for multiple sclerosis (MS)-risk after clinically isolated syndromes. However, biomarkers are often examined singly and their interrelation and precise aspects of their associated pathological processes remain unclear. Clarification of these relationships could aid the appropriate implementation of prognostic biomarkers in clinical practice. Objective To investigate the interrelation between biomarkers of inflammation, demyelination and neurodegeneration in acute optic neuritis and to assess their association to measures of MS risk. Material and Methods A prospective study at a tertiary referral centre from June 2011 to December 2012 of 56 patients with optic neuritis as a first demyelinating symptom and 27 healthy volunteers. Lumbar puncture was performed within 28 (median 16) days of onset. CSF levels of CXCL13, matrix metalloproteinase (MMP)-9, CXCL10, CCL-2, osteopontin and chitinase-3-like-1, myelin basic protein (MBP) and neurofilament light-chain (NF-L) were determined. MS-risk outcome measures were dissemination in space (DIS) of white matter lesions on cerebral MRI, CSF oligoclonal bands and elevated IgG-index. Results In the interrelation analysis the biomarkers showed close correlations within two distinct groups: Biomarkers of leukocyte infiltration (CXCL13, MMP-9 and CXCL10) were strongly associated (p<0.0001 for all). Osteopontin and chitinase-3-like-1 were also tightly associated (p<0.0001) and correlated strongly to tissue damage markers (NF-L and MBP). The biomarkers of leukocyte infiltration all associated strongly with MS-risk parameters, whereas CHI3L1 and MBP correlated with MRI DIS, but not with CSF MS-risk parameters and osteopontin and NF-L did not correlate with any MS-risk parameters. Conclusions Our findings suggest two distinct inflammatory processes: one of leukocyte infiltration, represented by CXCL13, CXCL10 and MMP-9, strongly associated with and potentially

  5. Initial Pattern of Optic Nerve Enhancement in Korean Patients with Unilateral Optic Neuritis

    PubMed Central

    Son, Dae Yong; Park, Kyung-Ah; Seok, Su Sie; Lee, Ju-Yeun

    2017-01-01

    Purpose The purpose of this study was to demonstrate whether the pattern of optic nerve enhancement in magnetic resonance imaging (MRI) can help to differentiate between idiopathic optic neuritis (ON), neuromyelitis optica (NMO), and multiple sclerosis (MS) in unilateral ON. Methods An MRI of the brain and orbits was obtained in patients with acute unilateral ON. Patients with ON were divided into three groups: NMO, MS, and idiopathic ON. The length and location of the abnormal optic nerve enhancement were compared for ON eyes with and without NMO or MS. The correlation between the pattern of optic nerve enhancement and the outcome of visual function was analyzed. Results Of the 36 patients with ON who underwent an MRI within 2 weeks of the onset, 19 were diagnosed with idiopathic ON, 9 with NMO, and 8 with MS. Enhancement of the optic nerve occurred in 21 patients (58.3%) and was limited to the orbital segment in 12 patients. Neither the length nor the location of the optic nerve enhancement was significantly correlated with visual functions other than contrast sensitivity or the diagnosis of idiopathic ON, MS, or NMO. Patients with greater extent of optic nerve sheath enhancement and more posterior segment involvement showed higher contrast sensitivity. Conclusions Our data revealed that the pattern of optic nerve enhancement was not associated with diagnosis of idiopathic ON, NMO, or MS in Korean patients with unilateral ON. We believe further studies that include different ethnic groups will lead to a more definitive answer on this subject. PMID:28243026

  6. Bilateral optic neuritis in pediatric systemic lupus erythematosus associated with antiphospholipid antibodies and neuromyelitis optica immunoglobulin.

    PubMed

    Wei, Wenxin; Zerfoss, Erica; Ashker, Lamees; Cantore, William A

    2010-05-21

    The authors report a case of a 16-year-old girl with a history of systemic lupus erythematosus who developed bilateral acute optic neuritis. Systemic lupus erythematosus can present with a vast array of neurological and ophthalmic complications, with optic neuritis being a rare but devastating manifestation and the major cause of blindness in these patients. The patient presented with an acute unilateral visual deficit that progressed to bilateral visual loss with no light perception over the course of days. Treatment included high-dose steroids, cyclophosphamide, intravenous immunoglobulin, and eventually rituximab. Furthermore, the patient was also seropositive for both antiphospholipid and neuromyelitis optica antibodies, which can have implications on prognosis and treatment options.

  7. Perivascular Enhancement in a Patient with Neuromyelitis Optica Spectrum Disease during an Optic Neuritis Attack.

    PubMed

    Pekcevik, Yeliz; Izbudak, Izlem

    2015-01-01

    We present a case with neuromyelitis optica spectrum disease (NMOSD) who had perivascular enhancement during an optic neuritis attack. Cloud-like enhancement, pencil-thin enhancement, and leptomeningeal enhancement have been defined as specific enhancement patterns to neuromyelitis optica (NMO). Perivascular enhancement has not been described before in NMO/NMOSD. This finding suggests that perivascular enhancement may also be seen in NMO/NMOSD patients.

  8. Diffusion tensor imaging of occult injury of optic radiation following optic neuritis in multiple sclerosis

    PubMed Central

    Chen, Jiafeng; Zhu, Lijun; Li, He; Lu, Ziwen; Chen, Xin; Fang, Shaokuan

    2016-01-01

    Multiple sclerosis (MS) is easily detected by routine magnetic resonance imaging (MRI). However, it is not possible to detect early or occult lesions in MS by routine MRI, and this may explain the inconsistency between the severity of the lesions found by MRI and the degree of clinical disability of patients with MS. The present study included 10 patients with relapsing-remitting MS and 10 healthy volunteers. Each patient underwent routine 3.0 T MRI, diffusion tensor imaging (DTI), and diffusion tensor tractography (DTT). Optic nerve and optic radiation were analyzed by DTI and DTT. The fractional anisotropy (FA), mean diffusivity (MD), λ//, and λ┴ values were measured. In the 10 patients with MS, 7 optic nerves were affected, and 13 optic nerves were not affected. Cranial MRI showed that optic nerve thickening and hyperintensity occurred in 2 patients with MS. In the directionally encoded color maps, a hypointensive green signal in the optic nerve was observed in 3 patients with MS. The FA values were significantly lower and the MD, λ//, and λ┴ values were significantly higher in the affected and unaffected optic nerves and optic radiations in patients with MS in comparison with controls (P<0.05). There were no significant differences in these values between the affected and unaffected optic nerves and optic radiation in patients with MS (P>0.05). Diffusion tensor imaging is sensitive in the detection of occult injury of the optic nerve and optic radiation following optic neuritis. Diffusion tensor imaging may be a useful tool for the early diagnosis, treatment and management of MS. PMID:27703508

  9. Permeability of the blood-brain barrier predicts conversion from optic neuritis to multiple sclerosis.

    PubMed

    Cramer, Stig P; Modvig, Signe; Simonsen, Helle J; Frederiksen, Jette L; Larsson, Henrik B W

    2015-09-01

    Optic neuritis is an acute inflammatory condition that is highly associated with multiple sclerosis. Currently, the best predictor of future development of multiple sclerosis is the number of T2 lesions visualized by magnetic resonance imaging. Previous research has found abnormalities in the permeability of the blood-brain barrier in normal-appearing white matter of patients with multiple sclerosis and here, for the first time, we present a study on the capability of blood-brain barrier permeability in predicting conversion from optic neuritis to multiple sclerosis and a direct comparison with cerebrospinal fluid markers of inflammation, cellular trafficking and blood-brain barrier breakdown. To this end, we applied dynamic contrast-enhanced magnetic resonance imaging at 3 T to measure blood-brain barrier permeability in 39 patients with monosymptomatic optic neuritis, all referred for imaging as part of the diagnostic work-up at time of diagnosis. Eighteen healthy controls were included for comparison. Patients had magnetic resonance imaging and lumbar puncture performed within 4 weeks of onset of optic neuritis. Information on multiple sclerosis conversion was acquired from hospital records 2 years after optic neuritis onset. Logistic regression analysis showed that baseline permeability in normal-appearing white matter significantly improved prediction of multiple sclerosis conversion (according to the 2010 revised McDonald diagnostic criteria) within 2 years compared to T2 lesion count alone. There was no correlation between permeability and T2 lesion count. An increase in permeability in normal-appearing white matter of 0.1 ml/100 g/min increased the risk of multiple sclerosis 8.5 times whereas having more than nine T2 lesions increased the risk 52.6 times. Receiver operating characteristic curve analysis of permeability in normal-appearing white matter gave a cut-off of 0.13 ml/100 g/min, which predicted conversion to multiple sclerosis with a sensitivity of

  10. Permeability of the blood–brain barrier predicts conversion from optic neuritis to multiple sclerosis

    PubMed Central

    Modvig, Signe; Simonsen, Helle J.; Frederiksen, Jette L.; Larsson, Henrik B. W.

    2015-01-01

    Optic neuritis is an acute inflammatory condition that is highly associated with multiple sclerosis. Currently, the best predictor of future development of multiple sclerosis is the number of T2 lesions visualized by magnetic resonance imaging. Previous research has found abnormalities in the permeability of the blood–brain barrier in normal-appearing white matter of patients with multiple sclerosis and here, for the first time, we present a study on the capability of blood–brain barrier permeability in predicting conversion from optic neuritis to multiple sclerosis and a direct comparison with cerebrospinal fluid markers of inflammation, cellular trafficking and blood–brain barrier breakdown. To this end, we applied dynamic contrast-enhanced magnetic resonance imaging at 3 T to measure blood–brain barrier permeability in 39 patients with monosymptomatic optic neuritis, all referred for imaging as part of the diagnostic work-up at time of diagnosis. Eighteen healthy controls were included for comparison. Patients had magnetic resonance imaging and lumbar puncture performed within 4 weeks of onset of optic neuritis. Information on multiple sclerosis conversion was acquired from hospital records 2 years after optic neuritis onset. Logistic regression analysis showed that baseline permeability in normal-appearing white matter significantly improved prediction of multiple sclerosis conversion (according to the 2010 revised McDonald diagnostic criteria) within 2 years compared to T2 lesion count alone. There was no correlation between permeability and T2 lesion count. An increase in permeability in normal-appearing white matter of 0.1 ml/100 g/min increased the risk of multiple sclerosis 8.5 times whereas having more than nine T2 lesions increased the risk 52.6 times. Receiver operating characteristic curve analysis of permeability in normal-appearing white matter gave a cut-off of 0.13 ml/100 g/min, which predicted conversion to multiple sclerosis with a

  11. Evaluation of Retinal Nerve Fiber Layer and Ganglion Cell Complex in Patients with Optic Neuritis or Neuromyelitis Optica Spectrum Disorders Using Optical Coherence Tomography in a Chinese Cohort.

    PubMed

    Tian, Guohong; Li, Zhenxin; Zhao, Guixian; Feng, Chaoyi; Li, Mengwei; Huang, Yongheng; Sun, Xinghuai

    2015-01-01

    We evaluate a cohort of optic neuritis and neuromyelitis optica (NMO) spectrum disorders patients in a territory hospital in China. The peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) were measured using spectral-domain OCT after 6 months of acute onset. The results showed that both the peripapillary RNFL and macular GCC were significantly thinner in all optic neuritis subtypes compared to controls. In addition, the recurrent optic neuritis and NMO groups showed more severe damage on the RNFL and GCC pattern.

  12. Evaluation of Retinal Nerve Fiber Layer and Ganglion Cell Complex in Patients with Optic Neuritis or Neuromyelitis Optica Spectrum Disorders Using Optical Coherence Tomography in a Chinese Cohort

    PubMed Central

    Tian, Guohong; Li, Zhenxin; Zhao, Guixian; Feng, Chaoyi; Li, Mengwei; Huang, Yongheng; Sun, Xinghuai

    2015-01-01

    We evaluate a cohort of optic neuritis and neuromyelitis optica (NMO) spectrum disorders patients in a territory hospital in China. The peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) were measured using spectral-domain OCT after 6 months of acute onset. The results showed that both the peripapillary RNFL and macular GCC were significantly thinner in all optic neuritis subtypes compared to controls. In addition, the recurrent optic neuritis and NMO groups showed more severe damage on the RNFL and GCC pattern. PMID:26649191

  13. Analysis of Fundus Photography and Fluorescein Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy and Optic Neuritis

    PubMed Central

    Kim, Min Kyung

    2016-01-01

    Purpose We evaluated fundus and fluorescein angiography (FAG) findings and characteristics that can help distinguish nonarteritic anterior ischemic optic neuropathy (NAION) from optic neuritis (ON). Methods Twenty-three NAION patients and 17 ON with disc swelling patients were enrolled in this study. We performed fundus photography and FAG. The disc-swelling pattern, hyperemia grade, presence of splinter hemorrhages, cotton-wool spots, artery/vein ratio and degree of focal telangiectasia were investigated. The FAG findings for each patient were compared with respect to the following features: the pattern of disc leakage in the early phase, arteriovenous (artery/vein) transit time (second), and the presence and pattern of the filling delay. Results Cotton-wool spots, focal telangiectasia, and venous congestion were more common in the affected eyes of NAION patients. Upon FAG, 76.5% of the patients in the ON group exhibited normal choroidal circulation. However, 56.5% of patients in the NAION group demonstrated abnormal filling defects, such as peripapillary, generalized, or watershed zone filling delays. Conclusions Fundus findings, including cotton-wool spots, focal telangiectasia, and venous congestion in the affected eye, may be clues that can be used to diagnose NAION. In addition, choroidal insufficiencies on FAG could be also helpful in differentiating NAION from ON. PMID:27478356

  14. Efficacy of vision restoration therapy after optic neuritis (VISION study): study protocol for a randomized controlled trial

    PubMed Central

    2012-01-01

    Background Optic neuritis is a frequent manifestation of multiple sclerosis. Visual deficits range from a minor impairment of visual functions through to complete loss of vision. Although many patients recover almost completely, roughly 35% of patients remain visually impaired for years, and therapeutic options for those patients hardly exist. Vision restoration therapy is a software-based visual training program that has been shown to improve visual deficits after pre- and postchiasmatic injury. The aim of this pilot study is to evaluate whether residual visual deficits after past or recent optic neuritis can be reduced by means of vision restoration therapy. Methods/design A randomized, controlled, patient- and observer-blinded clinical pilot study (VISION study) was designed to evaluate the efficacy of vision restoration therapy in optic neuritis patients. Eighty patients with a residual visual deficit after optic neuritis (visual acuity ≤0.7 and/or scotoma) will be stratified according to the time of optic neuritis onset (manifestation more than 12 months ago (40 patients, fixed deficit) versus manifestation 2 to 6 months ago (40 patients, recent optic neuritis)), and randomized into vision restoration therapy arm or saccadic training arm (control intervention). Patients will be instructed to complete a computer-based visual training for approximately 30 minutes each day for a period of 6 months. Patients and evaluators remain blinded to the treatment allocation throughout the study. All endpoints will be analyzed and P-values < 0.05 will be considered statistically significant. The primary outcome parameter will be the expansion of the visual field after 3 and 6 months of treatment as determined by static visual field perimetry and high resolution perimetry. Secondary outcome variables will include visual acuity at both low and high contrast, glare contrast sensitivity, visually evoked potentials, optical coherence tomography and other

  15. Recurrent optic neuritis and neuromyelitis optica-IgG following first and second human papillomavirus vaccinations.

    PubMed

    Chang, Hyeyeon; Lee, Hye Lim; Yeo, Minju; Kim, Ji Seon; Shin, Dong-Ick; Lee, Sang-Soo; Lee, Sung-Hyun

    2016-05-01

    Human papillomavirus (HPV) vaccine is widely used to prevent cervical cancer caused by certain types of HPV in girls and young women. Demyelinating disorders within months following HPV innoculation have been reported, but the causal link between HPV vaccination and the onset of demyelinating disorders have not been certain. We report a case of neuromyelitis optica spectrum disorder (NMOSD) that was noteworthy because optic neuritis (ON) occurred in a very close temporal association with both the first and second HPV vaccinations, which might suggest an association between HPV vaccination and the development of NMO-IgG and recurrent ON. This emphasizes the necessity for continuing surveillance for adverse events after HPV vaccination.

  16. Optic Neuritis Incidence is Increased in Spring Months in Patients with Asymptomatic Demyelinating Lesions

    PubMed Central

    Balashov, Konstantin E.; Pal, Gian; Rosenberg, Michael L.

    2010-01-01

    Background Optic neuritis (ON) patients can be divided based on the presence or absence of asymptomatic demyelinating lesions (ADL) on brain MRI. The presence of ADL is associated with an increased risk of progression to clinically-definite multiple sclerosis (CDMS). Methods The clinical data and brain MRI of 110 patients with acute unilateral ON were analyzed. Results Patients with ADL had a significantly higher incidence of ON in spring months as compared to patients with no ADL (p=0.0024). Increased incidence of ON in spring months was seen in patients with ADL whether or not they were diagnosed with CDMS on follow-up. PMID:20142310

  17. Visual field characteristics in neuromyelitis optica in absence of and after one episode of optic neuritis

    PubMed Central

    Merle, Harold; Olindo, Stéphane; Jeannin, Séverine; Hage, Rabih; Donnio, Angélique; Richer, Raymond; Cabre, Philippe

    2013-01-01

    Purpose Optic neuritis (ON) observed during neuromyelitis optica (NMO) is in most cases very severe and with poor prognosis. This study’s objective was to analyze visual field (VF) abnormalities observed in the absence of ON and post-ON episode. Methods Twenty-seven cases of both NMO and multiple sclerosis (MS) were selected. Thorough ophthalmologic exam was performed at least 6 months post-ON attack. The VF was collected using the Humphrey 750 perimeter. We used the central threshold tests 24-2 with FASTPAC strategy. The abnormalities were categorized based on the Optic Neuritis Treatment Trial classification. Results After one ON, 40% of the NMO group’s eyes showed total VF loss (P = 0.01), 21% showed abnormalities of neurologic aspect, and 27% showed fascicular abnormalities of which 12% were altitudinal. Given the total VF loss, the positive predictive value in favor of an NMO was 92.8% and the negative predictive value was 47.3%. Conclusion Alterations of the VF during the NMO differ from those observed in the course of the MS. One ON, blinding from the first attack, must call to mind an NMO. The altitudinal deficits point to a vascular mechanism. PMID:23807832

  18. CSF abnormalities can be predicted by VEP and MRI pathology in the examination of optic neuritis.

    PubMed

    Horwitz, Henrik; Degn, Matilda; Modvig, Signe; Larsson, Henrik B W; Wanscher, Benedikte; Frederiksen, Jette L

    2012-12-01

    Optic neuritis (ON) is linked to multiple sclerosis (MS). The presence of white matter lesions on cerebral magnetic resonance imaging (MRI) predicts the risk of MS after ON with considerable accuracy. Oligoclonal bands (OCB) are present in 95 % of MS patients, and a lumbar puncture can also be valuable in the evaluation of patients with ON. We analyzed CSF findings in patients referred with ON in the context of MRI and visual evoked potential (VEP) pathology. We assessed the possible contributory role of a lumbar puncture and weigh this against disadvantages of the procedure. Between February 2003 and November 2011, 505 patients were referred by ophthalmologists to the Clinic of Optic Neuritis, Glostrup Hospital, University of Copenhagen. None had MS prior to referral. A total of 437 were included in the study, and all underwent MRI, a lumbar puncture and VEP. Patients with other organic causes of their symptoms and patients with >3 months between onset and tests were excluded. All files were reviewed retrospectively. CSF leukocytes and the IgG index were elevated in 33 and 41 %, respectively, and OCBs were detected in 61 % of patients. CSF abnormalities correlated strongly with VEP and MRI (p < 0.0001). Patients with normal VEP and MRI had a 96 % probability of a normal lumbar puncture. The contributory role of a lumbar puncture in the evaluation of ON seems negligible when patients have a normal VEP and MRI. We suggest that all patients should be evaluated with VEP and MRI before deciding on a lumbar puncture.

  19. Calpain inhibitor attenuated optic nerve damage in acute optic neuritis in rats

    PubMed Central

    Das, Arabinda; Guyton, M. Kelly; Smith, Amena; Wallace, Gerald; McDowell, Misty L.; Matzelle, Denise D.; Ray, Swapan K.; Banik, Naren L.

    2012-01-01

    Optic neuritis (ON), which is an acute inflammatory autoimmune demyelinating disease of the central nervous system (CNS), often occurs in multiple sclerosis (MS). ON is an early diagnostic sign in most MS patients caused by damage to the optic nerve leading to visual dysfunction. Various features of both MS and ON can be studied following induction of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, in Lewis rats. Inflammation and cell death in the optic nerve, with subsequent damage to the retinal ganglion cells in the retina, are thought to correlate with visual dysfunction. Thus, characterizing the pathophysiological changes that lead to visual dysfunction in EAE animals may help develop novel targets for therapeutic intervention. We treated EAE animals with and without the calpain inhibitor calpeptin (CP). Our studies demonstrated that the Ca2+-activated neutral protease calpain was upregulated in the optic nerve following induction of EAE at the onset of clinical signs (OCS) of the disease and these changes were attenuated following treatment with CP. These reductions correlated with decreases in inflammation (cytokines, iNOS, COX-2, NF-κB), and microgliosis (i.e. activated microglia). We observed that calpain inhibition reduced astrogliosis (reactive astroglia) and expression of aquaporin 4 (AQP4). The balance of Th1/Th2 cytokine production and also expression of the Th1-related CCR5 and CXCR3 chemokine receptors influence many pathological processes and play both causative and protective roles in neuron damage. Our data indicated that CP suppressed cytokine imbalances. Also, Bax:Bcl-2 ratio, production of tBid, PARP-1, expression and activities of calpain and caspases, and internucleosomal DNA fragmentation were attenuated after treatment with CP. Our results demonstrated that CP decreased demyelination [loss of myelin basic protein (MBP)] and axonal damage [increase in dephosphorylated neurofilament protein (de-NFP), and also

  20. Treatment of optic neuritis with erythropoietin (TONE): a randomised, double-blind, placebo-controlled trial—study protocol

    PubMed Central

    Diem, Ricarda; Molnar, Fanni; Beisse, Flemming; Gross, Nikolai; Drüschler, Katharina; Heinrich, Sven P; Joachimsen, Lutz; Rauer, Sebastian; Pielen, Amelie; Sühs, Kurt-Wolfram; Linker, Ralf Andreas; Huchzermeyer, Cord; Albrecht, Philipp; Hassenstein, Andrea; Aktas, Orhan; Guthoff, Tanja; Tonagel, Felix; Kernstock, Christoph; Hartmann, Kathrin; Kümpfel, Tania; Hein, Katharina; van Oterendorp, Christian; Grotejohann, Birgit; Ihorst, Gabriele; Maurer, Julia; Müller, Matthias; Volkmann, Martin; Wildemann, Brigitte; Platten, Michael; Wick, Wolfgang; Heesen, Christoph; Schiefer, Ulrich; Wolf, Sebastian; Lagrèze, Wolf A

    2016-01-01

    Introduction Optic neuritis leads to degeneration of retinal ganglion cells whose axons form the optic nerve. The standard treatment is a methylprednisolone pulse therapy. This treatment slightly shortens the time of recovery but does not prevent neurodegeneration and persistent visual impairment. In a phase II trial performed in preparation of this study, we have shown that erythropoietin protects global retinal nerve fibre layer thickness (RNFLT-G) in acute optic neuritis; however, the preparatory trial was not powered to show effects on visual function. Methods and analysis Treatment of Optic Neuritis with Erythropoietin (TONE) is a national, randomised, double-blind, placebo-controlled, multicentre trial with two parallel arms. The primary objective is to determine the efficacy of erythropoietin compared to placebo given add-on to methylprednisolone as assessed by measurements of RNFLT-G and low-contrast visual acuity in the affected eye 6 months after randomisation. Inclusion criteria are a first episode of optic neuritis with decreased visual acuity to ≤0.5 (decimal system) and an onset of symptoms within 10 days prior to inclusion. The most important exclusion criteria are history of optic neuritis or multiple sclerosis or any ocular disease (affected or non-affected eye), significant hyperopia, myopia or astigmatism, elevated blood pressure, thrombotic events or malignancy. After randomisation, patients either receive 33 000 international units human recombinant erythropoietin intravenously for 3 consecutive days or placebo (0.9% saline) administered intravenously. With an estimated power of 80%, the calculated sample size is 100 patients. The trial started in September 2014 with a planned recruitment period of 30 months. Ethics and dissemination TONE has been approved by the Central Ethics Commission in Freiburg (194/14) and the German Federal Institute for Drugs and Medical Devices (61-3910-4039831). It complies with the Declaration of Helsinki

  1. Retinal Ganglion Cell Layer Thinning within One Month of Presentation for Optic Neuritis

    PubMed Central

    Kupersmith, Mark J.; Garvin, Mona K.; Wang, Jui-Kai; Durbin, Mary; Kardon, Randy

    2017-01-01

    Background Spectral domain optical coherence tomography (SD-OCT) reveals retina ganglion cell layer plus inner plexiform layer (GCL+IPL) and peripapillary nerve fiber layer (pRNFL) thinning in chronic optic nerve injury. At presentation, swelling of the pRNFL confounds evaluation of early axon loss. Objective We studied whether the GCL+IPL thins before the pRNFL, the trajectory of GCL+IPL loss and relationship to vision. Methods We prospectively evaluated 33 eyes (study) with new optic neuritis, using perimetry and SD-OCT with investigative 3-D layer segmentation and commercial 2-D segmentation to compute the GCL+IPL and pRNFL thickness. Results At presentation, GCL+IPL thickness (82.4±8.8 μm) did not differ from unaffected fellow eyes (81.2± 6.7 μm), via the 3-D method, while the 2-D method failed in 9% of study eyes. At one-two months, there was thinning of pRNFL in 10% and of GCL+IPL in 93% of study eyes. GCL+IPL reduction was greatest during the first two months. GCL+IPL thinning at one-two months correlated with GCL+IPL thinning at 6 months (r=0.84, p=0.01) and presentation visual acuity (r-0.48, p=0.006) and perimetric mean deviation (r=0.52, p=0.003). Conclusion GGL+IPL is an early biomarker of structural injury in optic neuritis as thinning develops within one-two months of onset, prior to pRNFL thinning. PMID:26362894

  2. Optic Neuritis

    MedlinePlus

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  3. Optic nerve atrophy and retinal nerve fibre layer thinning following optic neuritis: evidence that axonal loss is a substrate of MRI-detected atrophy.

    PubMed

    Trip, S Anand; Schlottmann, Patricio G; Jones, Stephen J; Li, Wai-Yung; Garway-Heath, David F; Thompson, Alan J; Plant, Gordon T; Miller, David H

    2006-05-15

    Magnetic resonance imaging (MRI) measures of brain atrophy are often considered to be a marker of axonal loss in multiple sclerosis (MS) but evidence is limited. Optic neuritis is a common manifestation of MS and results in optic nerve atrophy. Retinal nerve fibre layer (RNFL) imaging is a non-invasive way of detecting axonal loss following optic neuritis. We hypothesise that if the optic nerve atrophy that develops following optic neuritis is contributed to by axonal loss, it will correlate with thinning of the RNFL. Twenty-five patients were studied at least 1 year after a single unilateral attack of optic neuritis without recurrence, with a selection bias towards incomplete recovery. They had MR quantification of optic nerve cross-sectional area and optic nerve lesion length, as well as optical coherence tomography (OCT) measurement of mean RNFL thickness and macular volume, quantitative visual testing, and visual evoked potentials (VEPs). Fifteen controls were also studied. Significant optic nerve atrophy (mean decrease 30% versus controls), RNFL thinning (mean decrease 33% versus controls), and macular volume loss occurred in patients' affected eyes when compared with patients' unaffected eyes and healthy controls. The optic nerve atrophy was correlated with the RNFL thinning, macular volume loss, visual acuity, visual field mean deviation, and whole field VEP amplitude but not latency. These findings suggest that axonal loss contributes to optic nerve atrophy following a single attack of optic neuritis. By inference, axonal loss due to other post-inflammatory brain lesions is likely to contribute to the global MRI measure of brain atrophy in multiple sclerosis.

  4. Loss of Nrf2 exacerbates the visual deficits and optic neuritis elicited by experimental autoimmune encephalomyelitis

    PubMed Central

    Larabee, Chelsea M.; Desai, Shruti; Agasing, Agnieshka; Georgescu, Constantin; Wren, Jonathan D.; Axtell, Robert C.

    2016-01-01

    Purpose Optic neuritis, inflammation of the optic nerve, is experienced by most patients with multiple sclerosis (MS) and is typically characterized by episodes of acute, monocular vision loss. These episodes of inflammation can lead to damage or degeneration of the retinal ganglion cells (RGCs), the axons of which comprise the optic nerve. Experimental autoimmune encephalomyelitis (EAE) is a well-established model of MS in which mice are immunized to produce a neuroautoimmunity that recapitulates the cardinal hallmarks of human disease, namely, inflammation, demyelination, and neurodegeneration of the brain, spinal cord, and optic nerve. Inflammation-associated oxidative stress plays a key role in promoting spinal cord damage in EAE. However, the role of oxidative stress in optic neuritis and the associated visual deficits has not been studied. To address this gap in research, we sought to determine how a deficiency in the master antioxidant transcription factor (using nuclear factor-E2-related factor [Nrf2]-deficient mice) affects visual pathology in the EAE model. Methods EAE was induced in 8-week-old wild-type (WT) and Nrf2 knockout (KO) mice by immunization against the myelin oligodendrocyte glycoprotein (MOG) peptide antigen. Motor deficits were monitored daily, as was visual acuity using the established functional optokinetic tracking (OKT) assay. Mice were euthanized 21 days post-immunization for histological analyses. The optic nerves were paraffin-embedded and stained with hematoxylin and eosin (H&E) or immune cell type–specific antibodies to analyze inflammatory infiltrates. The retinas were flatmounted and stained with an RGC-specific antibody, and the RGCs were counted to assess neurodegeneration. T-helper (Th) cell-associated cytokines were measured in spleens with enzyme-linked immunosorbent assay (ELISA). Immune analyses of healthy, non-EAE mice were characterized with flow cytometry to assess the baseline immune cell profiles. Results Female Nrf2

  5. Anti-MOG (Myelin Oligodendrocyte Glycoprotein)–Positive Severe Optic Neuritis with Optic Disc Ischaemia and Macular Star

    PubMed Central

    Moura, Frederico Castelo; Sato, Douglas Kazutoshi; Rimkus, Carolina Medeiros; Apóstolos-Pereira, Samira Luisa; de Oliveira, Luana Michelli; Leite, Claudia Costa; Fujihara, Kazuo; Monteiro, Mario Luiz Ribeiro; Callegaro, Dagoberto

    2015-01-01

    Abstract A 44-year-old man presented with severe right visual loss. The right fundus examination showed marked optic disc oedema associated with partial macular star. Serological blood tests for infectious agents were all negative. Serum aquaporin-4 antibody was negative but anti-MOG (myelin oligodendrocyte glycoprotein) was positive. Magnetic resonance revealed extensive lesion in right optic nerve. There was no visual improvement after intravenous therapy. Patient had no further attacks after follow-up. Optic disc oedema with macular star is found in several infectious and non-inflammatory disorders, but it has not been reported in optic neuritis (ON) associated with autoantibodies to myelin oligodendrocyte glycoprotein (anti-MOG). PMID:27928371

  6. Serial visual evoked potentials in 90 untreated patients with acute optic neuritis.

    PubMed

    Frederiksen, J L; Petrera, J

    1999-10-01

    To establish the value of visual evoked potentials (VEPs) for monitoring disease evolution, we undertook a population-based study of 90 untreated patients 12 to 57 years of age (median, 32 years) at the onset of optic neuritis (ON) and after 2, 4, 12, and 52 weeks. Optic neuritis was monosymptomatic (AMON) in 58 patients and part of the clinically definite multiple sclerosis (CDMS) in 32 patients. The VEP was abnormal in eyes with acute ON in 69 (77%) of 90 patients at onset and in 80 (89%) of 90 patients at one or more of the follow-up sessions. In eyes with acute ON, normalization of an initially abnormal VEP was observed during 1-year follow-up in 13 (19%) of 69 patients. At onset of ON, VEP was abnormal in 35% of the clinically unaffected eyes. By parametric analysis of variance, the latencies (P = 0.0058), the amplitudes (P = 0.0298), and the combined VEP scores (P = 0.0345) in the eyes with acute ON were significantly associated with the time after onset. The latencies were influenced by the presence of CDMS (P = 0.0033), whereas the amplitudes were influenced by visual acuity (P = 0.0000). When visual acuity was included in a multifactor model, the time after onset was, however, not significantly associated with the amplitude (P = 0.8826). The mean latency of the VEPs in eyes with acute ON was significantly shorter in AMON than in ON as part of CDMS. This study provides evidence that VEP abnormality is often transitory, and that VEP often normalizes during follow-up. The diagnostic yield is increased by repeating VEP in the spontaneous course of acute ON. Visual evoked potential is a sensitive tool for revealing subclinical lesions.

  7. First-ever optic neuritis: distinguishing subsequent neuromyelitis optica from multiple sclerosis.

    PubMed

    Lim, Young-Min; Pyun, So Young; Lim, Hyun Taek; Jeong, In Hye; Kim, Kwang-Kuk

    2014-05-01

    To identify factors distinguishing subsequent neuromyelitis optica (NMO) from multiple sclerosis (MS) after first-ever optic neuritis (ON), we compared ophthalmic findings and MRI features of 24 NMO and 55 MS patients who initially presented with ON. The female-to-male ratio was higher, and bilateral ON was more common in NMO patients than in MS patients (p = 0.044 and p = 0.020, respectively). The visual acuity (VA) score was higher in NMO patients (p = 0.034), and a greater proportion of NMO patients had a VA score ≥ 5 (p = 0.003). The frequency of patients without pattern-reversal and flash visual evoked potentials was higher in the NMO group (p = 0.015). Brain MRI abnormalities were more common in the MS group (p = 0.001). The optic chiasm was affected in 25 % of NMO patients and was unaffected in MS patients, although it did not reach statistical significance (p = 0.096). There were no differences with respect to the severity of swelling and enhancement of the optic nerve. In conclusion, severe optic nerve damage at the first ON attack was associated with subsequent development of NMO, whereas presence of brain MRI abnormalities was associated with developing MS.

  8. Celastrol Attenuates Multiple Sclerosis and Optic Neuritis in an Experimental Autoimmune Encephalomyelitis Model

    PubMed Central

    Yang, Hongbin; Liu, Chang; Jiang, Jie; Wang, Yuena; Zhang, Xiaoyu

    2017-01-01

    This study was aimed to evaluate the effects of celastrol, a natural compound with multiple bioactivities, on multiple sclerosis and optic neuritis (ON) in rat experimental autoimmune encephalomyelitis (EAE). EAE was induced in Sprague Dawley rats using myelin basic protein, and the animals received daily intraperitoneal injections of celastrol or vehicle for 13 days. The EAE rats showed abnormal neurobehavior and inflammatory infiltration and demyelination in the spinal cord. Significantly upregulated mRNA expression of pro-inflammatory cytokines interferon-γ and interleukin-17 and downregulated anti-inflammatory cytokines interleukin-4 were found in the spinal cord of EAE rats. In the study of ON, severely inflammatory responses like in the spinal cord were also seen in the optic nerve, as well as obvious microgliosis. Furthermore, activation of nuclear factor kappa-B and upregulated inducible nitric oxide synthase was observed in the optic nerve. In addition, apoptosis of retinal ganglion cells and dysregulation of apoptotic-associated proteins in the optic nerve were found in EAE rats. Treatment of celastrol potently restored these changes. In most of the indexes, the effects of high dose of celastrol were better than the low dose. Our data conclude that administration of celastrol attenuates multiple sclerosis and ON in EAE via anti-inflammatory and anti-apoptotic effects. These findings provide new pre-clinical evidence for the use of celastrol in treatment of multiple sclerosis. PMID:28239352

  9. Changes of CXCL12, CXCL14 and PDGF levels in the brain of patients with idiopathic demyelinating optic neuritis and neuromyelitis optica.

    PubMed

    Tingjun, Chen; Zhaohui, Li; Zhaocai, Jiang; Zihao, Liu; Quangang, Xu; Dehui, Huang; Qing, Lin; Shihui, Wei

    2015-02-15

    The CXC chemokines (CXC-motif ligand 12 and CXC-motif ligand 14) and platelet-derived growth factor are suggested to modulate remyelination in the course of many demyelinating diseases. The present study compared the difference in the brain levels of these chemokines between patients with idiopathic demyelinating optic neuritis (IDON) and neuromyelitis optica (NMO) by measuring their concentrations in the cerebrospinal fluid using an enzyme linked immunosorbent assay. Our data indicate that the prognosis of neuritis depends on the remyelinating process that is impaired due to decreased chemokines. The much lower levels of chemokines would specifically indicate the severe neuritis, such as NMO.

  10. Bilateral atypical optic neuritis associated with tuberculosis in an immunocompromised patient.

    PubMed

    Jaafar, Juanarita; Hitam, Wan Hazabbah Wan; Noor, Raja Azmi Mohd

    2012-07-01

    A 27 year-old lady, presented with sudden loss of vision in the right eye for a week. It was followed by poor vision in the left eye after 3 days. It involved the whole entire visual field and was associated with pain on eye movement. She was diagnosed to have miliary tuberculosis and retroviral disease 4 months ago. She was started on anti-TB since then but defaulted highly active anti-retroviral therapy (HAART). On examination, her visual acuity was no perception of light in the right eye and 6/120 (pinhole 3/60) in the left eye. Anterior segment in both eyes was unremarkable. Funduscopy showed bilateral optic disc swelling with presence of multiple foci of choroiditis in the peripheral retina. The vitreous and retinal vessels were normal. Chest radiography was normal. CT scan of orbit and brain revealed bilateral enhancement of the optic nerve sheath that suggest the diagnosis of bilateral atypical optic neuritis. This patient was managed with infectious disease team. She was started on HAART and anti-TB treatment was continued. She completed anti-TB treatment after 9 months without any serious side effects. During follow up the visual acuity in both eyes was not improved. However, funduscopy showed resolving of disc swelling and choroiditis following treatment.

  11. Neuromyelitis optica-IgG+ optic neuritis associated with celiac disease and dysgammaglobulinemia: a role for tacrolimus?

    PubMed

    Meyts, Isabelle; Jansen, Katrien; Renard, Marleen; Bossuyt, Xavier; Roelens, Filip; Régal, Luc; Lagae, Lieven; Buyse, Gunnar

    2011-05-01

    We present a pediatric case of recurrent optic neuritis, celiac disease, partial IgA and IgG3 deficiency in the context of anti-aquaporin-4 auto-immunity and familial IgA deficiency with celiac disease. Treatment with tacrolimus was successful in preventing disease relapses. This case stresses the relevance of central nervous system anti-aquaporin-4 auto-immunity in a broader context of immune dysregulation and neuro-immunology.

  12. ATON: results from a Phase II randomized trial of the B-cell-targeting agent atacicept in patients with optic neuritis.

    PubMed

    Sergott, Robert C; Bennett, Jeffrey L; Rieckmann, Peter; Montalban, Xavier; Mikol, Daniel; Freudensprung, Ulrich; Plitz, Thomas; van Beek, Johan

    2015-04-15

    The 36-week ATON study compared the efficacy and safety of atacicept with matching placebo in 34 patients with unilateral optic neuritis as a clinically isolated syndrome. Atacicept (150mg) was administered twice weekly for 4weeks (loading period), then once weekly for 32weeks. The ATON study was terminated prematurely by the sponsor when an independent Data and Safety Monitoring Board review observed increased multiple sclerosis (MS)-related disease activity in the atacicept arms of the concurrent ATAcicept in MS (ATAMS) study. Analysis of the prematurely terminated ATON study showed that the mean (standard deviation) change from baseline in retinal nerve fiber layer thickness at last observed value in the affected eye was -8.6 (10.1) μm in patients treated with atacicept (n=15) compared with -17.3 (15.2) μm in patients treated with placebo (n=16). In the atacicept treatment group, a higher proportion of patients converted to clinically definite MS during the double-blind period compared with placebo (35.3% [6/17] vs 17.6% [3/17]). Treatment-emergent adverse events were similar across both treatment groups in the double-blind period. A dichotomy emerged with more atacicept-treated patients converting to relapsing-remitting MS compared with placebo-treated patients, despite the same patients experiencing less axonal loss after an optic neuritis event.

  13. Amiloride Clinical Trial In Optic Neuritis (ACTION) protocol: a randomised, double blind, placebo controlled trial

    PubMed Central

    McKee, Justin B; Elston, John; Evangelou, Nikos; Gerry, Stephen; Fugger, Lars; Kennard, Christopher; Kong, Yazhuo; Palace, Jacqueline; Craner, Matthew

    2015-01-01

    Introduction Neurodegeneration is a widely accepted contributor to the development of long-term disability in multiple sclerosis (MS). While current therapies in MS predominantly target inflammation and reduce relapse rate they have been less effective at preventing long-term disability. The identification and evaluation of effective neuroprotective therapies within a trial paradigm are key unmet needs. Emerging evidence supports amiloride, a licenced diuretic, as a neuroprotective agent in MS through acid sensing ion channel blockade. Optic neuritis (ON) is a common manifestation of MS with correlates of inflammation and neurodegeneration measurable within the visual pathways. Amiloride Clinical Trial In Optic Neuritis (ACTION) will utilise a multimodal approach to assess the neuroprotective efficacy of amiloride in acute ON. Methods and analysis 46 patients will be recruited within 28 days from onset of ON visual symptoms and randomised on a 1:1 basis to placebo or amiloride 10 mg daily. Double-blinded treatment groups will be balanced for age, sex and visual loss severity by a random-deterministic minimisation algorithm. The primary objective is to demonstrate that amiloride is neuroprotective in ON as assessed by scanning laser polarimetry of the peripapillary retinal nerve fibre layer (RNFL) thickness at 6 months in the affected eye compared to the unaffected eye at baseline. RNFL in combination with further retinal measures will also be assessed by optical coherence tomography. Secondary outcome measures on brain MRI will include cortical volume, diffusion-weighted imaging, resting state functional MRI, MR spectroscopy and magnetisation transfer ratio. In addition, high and low contrast visual acuity, visual fields, colour vision and electrophysiology will be assessed alongside quality of life measures. Ethics and dissemination Ethical approval was given by the south central Oxford B research ethics committee (REC reference: 13/SC/0022). The findings

  14. Calpain Inhibition Attenuates Apoptosis of Retinal Ganglion Cells in Acute Optic Neuritis

    PubMed Central

    Smith, Amena W.; Das, Arabinda; Guyton, M. Kelly; Ray, Swapan K.; Rohrer, Baerbel

    2011-01-01

    Purpose. Optic neuritis (ON), inflammation of the optic nerve, is strongly associated with the pathogenesis of multiple sclerosis (MS) and is initiated by the attack of autoreactive T cells against self-myelin antigens, resulting in demyelination, degeneration of retinal ganglion cells (RGCs), and cumulative visual impairment. Methods. Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats on day 0, and animals received daily intraperitoneal injections of calpain inhibitor (calpeptin) or vehicle from day 1 until killed. Retinal cell death was analyzed by DNA fragmentation, and surviving ganglion cells were quantified after double labeling of retinal tissue with TUNEL and Brn3a. The expression of apoptotic and inflammatory proteins was determined by Western blotting. Results. It was demonstrated that calpain inhibition downregulates expression of proapoptotic proteins and the proinflammatory molecule nuclear factor-kappa B (NF-κB) in the retina of Lewis rats with acute EAE. Immunofluorescent labeling revealed that apoptotic cells in the RGC layer of vehicle-treated EAE animals were Brn3a positive, and a moderate dose of calpeptin dramatically reduced the frequency of apoptotic RGCs. Conclusions. These results suggest that calpain inhibition might be a useful supplement to immunomodulatory therapies such as corticosteroids in ON, due to its neuroprotective effect on RGCs. PMID:21613375

  15. Vestibular neuritis.

    PubMed

    Jeong, Seong-Hae; Kim, Hyo-Jung; Kim, Ji-Soo

    2013-07-01

    Vestibular neuritis is the most common cause of acute spontaneous vertigo. Vestibular neuritis is ascribed to acute unilateral loss of vestibular function, probably due to reactivation of herpes simplex virus in the vestibular ganglia. The diagnostic hallmarks of vestibular neuritis are spontaneous horizontal-torsional nystagmus beating away from the lesion side, abnormal head impulse test for the involved semicircular canals, ipsilesional caloric paresis, decreased responses of vestibular-evoked myogenic potentials during stimulation of the affected ear, and unsteadiness with a falling tendency toward the lesion side. Vestibular neuritis preferentially involves the superior vestibular labyrinth and its afferents. Accordingly, the function of the posterior semicircular canal and saccule, which constitute the inferior vestibular labyrinth, is mostly spared in vestibular neuritis. However, because the rare subtype of inferior vestibular neuritis lacks the typical features of vestibular neuritis, it may be misdiagnosed as a central vestibular disorder. Even in the patient with the typical pattern of spontaneous nystagmus observed in vestibular neuritis, brain imaging is indicated when the patient has unprecedented headache, negative head impulse test, severe unsteadiness, or no recovery within 1 to 2 days. Symptomatic medication is indicated only during the acute phase to relieve the vertigo and nausea/vomiting. Vestibular rehabilitation hastens the recovery. The efficacy of topical and systemic steroids requires further validation.

  16. [Comparison of the Aulhorn flicker test with visual evoked potentials in the diagnosis of optic neuritis].

    PubMed

    Trauzettel-Klosinski, S; Diener, H C; Fahle, M

    1990-01-01

    The Aulhorn flicker test and visual evoked cortical potentials (VEP) are of great value for the diagnosis of optic neuritis (ON). In the present study, the two methods were compared for the first time within the same group of patients. The study comprised 405 eyes (175 suffering from active or subsided ON). The results were evaluated with a double-blind procedure. With the flicker test, the subjective brightness of flickering light is determined as a function of the flicker frequency. This test gives pathological results only in active ON and normalizes when the active phase is over. The test can discriminate between active and subsided ON as well as between the recurrent and chronic courses of the disease. Differentiation is not possible with the VEP, since the VEP latencies are prolonged even after the end of the active period of the disease. The sensitivity of the flicker test was 84.4%. The sensitivity of the VEP was 72.7% for our group of patients suffering from ON if the criterion of increased latency was used alone. In the diagnosis of multiple sclerosis (MS), the proportion of correctly identified pathological VEP results is increased because of the detection of demyelination of the optic nerve that causes no clinical symptoms. The specificity of the flicker test was 97.8% and that of the VEP 86.5%. If both methods were combined, the sensitivity was 98.4% and specificity 99.6%. The two methods obviously have different characteristics and seem to rely upon different demyelination effects. Each method has its advantages and disadvantages as well as optimal indications.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Magnetisation transfer ratios and transverse magnetisation decay curves in optic neuritis: correlation with clinical findings and electrophysiology.

    PubMed Central

    Thorpe, J W; Barker, G J; Jones, S J; Moseley, I; Losseff, N; MacManus, D G; Webb, S; Mortimer, C; Plummer, D L; Tofts, P S

    1995-01-01

    Conventional MRI sequences do not permit the distinction between the different pathological characteristics (oedema, demyelination, gliosis, axonal loss) of the multiple sclerosis plaque. Magnetisation transfer imaging and transverse magnetisation decay curve (tMDC) analysis may be more specific. These techniques have been applied to the optic nerves in 20 patients with optic neuritis and the results correlated with clinical and visual evoked potential (VEP) findings. tMDC analysis failed to identify separate intracellular and extracellular water compartments within the optic nerve but gave a measure of transverse relaxation time (T2) without the confounding effects of CSF in the nerve sheath. Both T2 and magnetisation transfer ratio (MTR) were abnormal after an episode of optic neuritis. T2 did not correlate with visual function or with VEP latency or amplitude. There was a significant correlation between MTR reduction and prolongation of VEP latency: this increased latency may reflect an effect of myelin loss on MTR. Longer lesions were associated with worse visual outcome, implying that the overall extent of pathological involvement is likely to influence the degree of functional deficit. Images PMID:8530932

  18. The Farnsworth-Munsell 100 hue test in the first episode of demyelinating optic neuritis.

    PubMed

    Ménage, M J; Papakostopoulos, D; Dean Hart, J C; Papakostopoulos, S; Gogolitsyn, Y

    1993-02-01

    The Farnsworth-Munsell 100 hue test (F-M 100) was used to examine 30 patients with their first episode of unilateral demyelinating optic neuritis (DON) at presentation, after 6 weeks and after 6 months. Twelve patients satisfactorily completed the test with the affected eye at presentation. This number had increased to 23 by 6 weeks and to 27 by 6 months. No patient with a visual acuity of LogMAR 0.86 (Snellen equivalent approx 6/43) or worse, could complete the test. The mean total error score of affected eyes showed significant improvement at each subsequent examination but was always worse than the non-affected eyes. There was a significant correlation between total error scores and visual acuities of affected eyes at presentation and after 6 months. Fourteen patients recovered a visual acuity of LogMAR 0.0 (Snellen equivalent 6/6) or better but the total error scores of the affected eyes were significantly worse than the non-affected eyes (p = 0.017), indicating that defective colour vision is an indicator of a previous episode of DON despite the recovery of normal visual acuity. DON is reported to produce a red-green (Type II) axis of colour defect but individual F-M 100 polar diagrams were usually generally abnormal and did not show any predominance of recognisable axis of colour defect at any examination. Group averaging of the F-M 100 data from such a well-defined group of patients with acute DON revealed a significant bipolar abnormality in the tritan (blue-yellow) axis at presentation which was not demonstrated at the subsequent examinations or at any examination of the non-affected eyes.

  19. Dichoptic Metacontrast Masking Functions to Infer Transmission Delay in Optic Neuritis

    PubMed Central

    Bruchmann, Maximilian; Korsukewitz, Catharina; Krämer, Julia; Wiendl, Heinz; Meuth, Sven G.

    2016-01-01

    Optic neuritis (ON) has detrimental effects on the transmission of neuronal signals generated at the earliest stages of visual information processing. The amount, as well as the speed of transmitted visual signals is impaired. Measurements of visual evoked potentials (VEP) are often implemented in clinical routine. However, the specificity of VEPs is limited because multiple cortical areas are involved in the generation of P1 potentials, including feedback signals from higher cortical areas. Here, we show that dichoptic metacontrast masking can be used to estimate the temporal delay caused by ON. A group of 15 patients with unilateral ON, nine of which had sufficient visual acuity and volunteered to participate, and a group of healthy control subjects (N = 8) were presented with flashes of gray disks to one eye and flashes of gray annuli to the corresponding retinal location of the other eye. By asking subjects to report the subjective visibility of the target (i.e. the disk) while varying the stimulus onset asynchrony (SOA) between disk and annulus, we obtained typical U-shaped masking functions. From these functions we inferred the critical SOAmax at which the mask (i.e. the annulus) optimally suppressed the visibility of the target. ON-associated transmission delay was estimated by comparing the SOAmax between conditions in which the disk had been presented to the affected and the mask to the other eye, and vice versa. SOAmax differed on average by 28 ms, suggesting a reduction in transmission speed in the affected eye. Compared to previously reported methods assessing perceptual consequences of altered neuronal transmission speed the presented method is more accurate as it is not limited by the observers’ ability to judge subtle variations in perceived synchrony. PMID:27711139

  20. Retinitis Pigmentosa and Bilateral Idiopathic Demyelinating Optic Neuritis in a 6-Year-Old Boy with OFD1 Gene Mutation

    PubMed Central

    Wang, Xun; Zheng, Cong; Liu, Wen

    2017-01-01

    To identify the cause of a sudden binocular vision decrease in patients with retinitis pigmentosa and bilateral idiopathic demyelinating optic neuritis is difficult, but early diagnosis and treatment significantly improve the prognosis. Here, we report a 6-year-old boy with a progressive binocular vision decrease in 38 days. The patient had a history of night blindness, a mottled retina without pigmentation, extinguished electroretinographic response, tritanopia, and an absent ellipsoid zone outside the macula fovea by optical coherence tomography in both eyes. His condition was diagnosed as retinitis pigmentosa (RP) with idiopathic demyelinating optic neuritis (IDON). After corticosteroid therapy, visual acuity recovered to OD: 0.5 and OS: 0.4. Genetic analysis revealed a G985S variant in the oral-facial-digital syndrome 1 gene. Ophthalmologists should pay attention to the existence of other complications in patients with RP who suffer a sudden decrease in vision. A gene survey can help clarify this diagnosis. To our knowledge, this is the first report of a patient with RP and ON, as well as genetic testing results. Nevertheless, the pathogenicity of the variant needs further confirmation. PMID:28191358

  1. [Optic neuritis in childhood. A pediatric series, literature review and treatment approach].

    PubMed

    Lopez-Martin, D; Martinez-Anton, J

    2016-08-01

    Introduccion. En la edad pediatrica, la forma mas frecuente de neuritis optica se presenta generalmente despues de un cuadro infeccioso, con edema de papila, que suele ser bilateral y tiene buen pronostico. La conversion a esclerosis multiple es infrecuente. Objetivo. Presentar las caracteristicas clinicas y de laboratorio de una serie pediatrica de neuritis optica. Pacientes y metodos. Se analiza una serie de 17 casos de neuritis optica en niños y jovenes de 4 a 14 años, referidos entre los años 2000 y 2015. Resultados. La edad mediana de la serie fue de 11 años. Predominaron los pacientes de sexo femenino y el antecedente infeccioso fue poco frecuente; en cinco pacientes, la afectacion fue bilateral, y cuatro casos se presentaron como neuritis optica retrobulbar. La resonancia magnetica mostro hiperintensidad en T2 en los nervios opticos afectados en cinco pacientes. El estudio del liquido cefalorraquideo y bandas oligoclonales fue normal en todos los casos. Los pacientes, tratados con metilprednisolona intravenosa, tuvieron buena recuperacion. Solo en tres casos se comprobo una evolucion posterior a esclerosis multiple. Conclusiones. En esta serie, los casos que evolucionaron a esclerosis multiple no mostraron diferencias clinicas, aunque si presentaron mayor cantidad de lesiones hiperintensas en la resonancia magnetica. Este hecho, descrito en trabajos previos, apoya nuestro esquema diagnostico y terapeutico en un intento por acercarnos al manejo optimo de esta patologia.

  2. Clinical Features and Visual Outcomes of Optic Neuritis in Chinese Children

    PubMed Central

    Zhou, Huanfen; Xu, Quangang; Tan, Shaoying; Zhao, Shuo; Yang, Mo; Peng, Chunxia

    2016-01-01

    Purpose. Although optic neuritis (ON) in children is relatively common, visual outcomes and factors associated with the condition have not been well documented. The aim of this study was to evaluate the clinical features and visual outcomes of ON in Chinese children. Methods. Patients with a first episode of ON at a tertiary neuroophthalmic centre in China were assessed and followed up for at least three months. Visual outcomes and clinical, laboratory, and neuroimaging findings were reviewed. In patients with bilateral ON, only the eyes with worse visual acuity (VA) at presentation were used for statistical analysis. Results. Seventy-six children (76 eyes) with a first episode of ON were included. The mean age was 11.8 years, 60.5% were females, and 48.7% had bilateral involvement. The children were followed up for an average of 18.5 months (age range, 3–48 months). Vision loss at presentation was severe, with VA < 20/200 in 37 eyes (48.7%). At the final visit, 3 (3.9%) eyes had VA of at least 20/20, and 41 (53.9%) eyes had VA of at least 20/40. The final VA in 35 eyes (46.1%) was worse than 20/40. Children aged ≤ 10 years had better predicted visual outcomes when compared to children over 10 years (odds ratio = 2.73, 95% confidential interval: 1.05–7.07, and P = 0.039). The other features of this cohort, such as sex, experienced bilateral attack, VA at presentation, presence of optic disc edema, systemic diseases, magnetic resonance imaging (MRI) findings, and aquaporin-4 (AQP-4) antibody status, were not significantly correlated with the final visual outcome. Conclusion. The data revealed the clinical characteristics and visual outcomes of ON in Chinese children. ON in children was associated with severe vision loss and relatively good visual recovery. The age at onset could predict the final visual function. PMID:27725883

  3. Bioluminescence and Near-infrared Imaging of Optic Neuritis and Brain Inflammation in the EAE Model of Multiple Sclerosis in Mice.

    PubMed

    Schmitz, Katja; Tegeder, Irmgard

    2017-03-01

    Experimental autoimmune encephalomyelitis (EAE) in SJL/J mice is a model for relapsing-remitting multiple sclerosis (RRMS). Clinical EAE scores describing motor function deficits are basic readouts of the immune-mediated inflammation of the spinal cord. However, scores and body weight do not allow for an in vivo assessment of brain inflammation and optic neuritis. The latter is an early and frequent manifestation in about 2/3 of MS patients. Here, we show methods for bioluminescence and near-infrared live imaging to assess EAE evoked optic neuritis, brain inflammation, and blood-brain barrier (BBB) disruption in living mice using an in vivo imaging system. A bioluminescent substrate activated by oxidases primarily showed optic neuritis. The signal was specific and allowed the visualization of medication effects and disease time courses, which paralleled the clinical scores. Pegylated fluorescent nanoparticles that remained within the vasculature for extended periods of time were used to assess the BBB integrity. Near-infrared imaging revealed a BBB leak at the peak of the disease. The signal was the strongest around the eyes. A near-infrared substrate for matrix metalloproteinases was used to assess EAE-evoked inflammation. Auto-fluorescence interfered with the signal, requiring spectral unmixing for quantification. Overall, bioluminescence imaging was a reliable method to assess EAE-associated optic neuritis and medication effects and was superior to the near-infrared techniques in terms of signal specificity, robustness, ease of quantification, and cost.

  4. Takayasu arteritis presenting as isolated anterior ischemic optic neuropathy.

    PubMed

    Tian, Guohong; Chen, Qian; Wang, Wenji

    2017-04-07

    Takayasu arteritis (TA) is a systemic vasculitis of unknown etiology that affects the aorta and its primary branches or large arteries in the proximal upper or lower extremities. Ocular manifestations of TA include microaneurysm formation, small-vessel dilation, arteriovenous anastomosis, retinal ischemia, and neovascular glaucoma. We herein report a case involving a 23-year-old Asian woman who presented with isolated acute anterior ischemic optic neuropathy and was initially misdiagnosed with optic neuritis. The stenosis and occlusion of the aorta and other proximal arteries on angiography confirmed the diagnosis of TA.

  5. Vestibular neuritis.

    PubMed

    Strupp, Michael; Brandt, Thomas

    2009-11-01

    The key signs and symptoms of vestibular neuritis are rotatory vertigo with an acute onset lasting several days, horizontal spontaneous nystagmus (with a rotational component) toward the unaffected ear, a pathologic head-impulse test toward the affected ear, a deviation of the subjective visual vertical toward the affected ear, postural imbalance with falls toward the affected ear, and nausea. The head-impulse test and caloric irrigation show an ipsilateral deficit of the vestibuloocular reflex. Vestibular neuritis is the third most common cause of peripheral vestibular vertigo. It has an annual incidence of 3.5 per 100,000 population and accounts for 7% of the patients at outpatient clinics specializing in the treatment of vertigo. The reactivation of a latent herpes simplex virus type 1 (HSV-1) infection is the most likely cause, as HSV-1 DNA and RNA have been detected in human vestibular ganglia. Vestibular neuritis is a diagnosis of exclusion. Relevant differential diagnoses are vestibular pseudoneuritis due to acute pontomedullary brainstem lesions or cerebellar nodular infarctions, vestibular migraine, and monosymptomatically beginning Ménière's disease. Recovery from vestibular neuritis is due to a combination of (a) peripheral restoration of labyrinthine function, usually incomplete but can be improved by early treatment with corticosteroids, which cause a recovery rate of 62% within 12 months; (b) mainly somatosensory and visual substitution; and (c) central compensation, which can be improved by vestibular exercise.

  6. A Rare Case of Bilateral Optic Neuritis and Guillain-Barré Syndrome Post Mycoplasma pneumoniae Infection.

    PubMed

    Baheerathan, Aravindhan; Ross Russell, Amy; Bremner, Fion; Farmer, Simon F

    2017-02-01

    Neurological complications are the most commonly encountered extra-pulmonary manifestation of infection with Mycoplasma pneumoniae (M. pneumoniae). Here the authors report the case of a 39-year-old woman who was admitted with acute-onset bilateral visual loss coinciding with ascending numbness. Clinical examination, neurological imaging, and nerve conduction studies revealed a syndrome of bilateral optic neuritis and Guillain-Barré syndrome (GBS). Serological testing confirmed recent exposure to M. pneumoniae. The patient did not experience any clinical benefit with pulsed intravenous methylprednisolone but demonstrated marked clinical and radiological improvement following 5 days of plasma exchange. This report will explore the diagnostic and therapeutic approach to patients with neuro-ophthalmological and neurological complications of M. pneumoniae infection in addition to discussing previously encountered cases.

  7. Dynamic Visual Tests to Identify and Quantify Visual Damage and Repair Following Demyelination in Optic Neuritis Patients

    PubMed Central

    Raz, Noa; Hallak, Michal; Ben-Hur, Tamir; Levin, Netta

    2014-01-01

    In order to follow optic neuritis patients and evaluate the effectiveness of their treatment, a handy, accurate and quantifiable tool is required to assess changes in myelination at the central nervous system (CNS). However, standard measurements, including routine visual tests and MRI scans, are not sensitive enough for this purpose. We present two visual tests addressing dynamic monocular and binocular functions which may closely associate with the extent of myelination along visual pathways. These include Object From Motion (OFM) extraction and Time-constrained stereo protocols. In the OFM test, an array of dots compose an object, by moving the dots within the image rightward while moving the dots outside the image leftward or vice versa. The dot pattern generates a camouflaged object that cannot be detected when the dots are stationary or moving as a whole. Importantly, object recognition is critically dependent on motion perception. In the Time-constrained Stereo protocol, spatially disparate images are presented for a limited length of time, challenging binocular 3-dimensional integration in time. Both tests are appropriate for clinical usage and provide a simple, yet powerful, way to identify and quantify processes of demyelination and remyelination along visual pathways. These protocols may be efficient to diagnose and follow optic neuritis and multiple sclerosis patients. In the diagnostic process, these protocols may reveal visual deficits that cannot be identified via current standard visual measurements. Moreover, these protocols sensitively identify the basis of the currently unexplained continued visual complaints of patients following recovery of visual acuity. In the longitudinal follow up course, the protocols can be used as a sensitive marker of demyelinating and remyelinating processes along time. These protocols may therefore be used to evaluate the efficacy of current and evolving therapeutic strategies, targeting myelination of the CNS. PMID

  8. Myelin-specific Th17 cells induce severe relapsing optic neuritis with irreversible loss of retinal ganglion cells in C57BL/6 mice

    PubMed Central

    Larabee, Chelsea M.; Hu, Yang; Desai, Shruti; Georgescu, Constantin; Wren, Jonathan D.; Axtell, Robert C.

    2016-01-01

    Purpose Optic neuritis affects most patients with multiple sclerosis (MS), and current treatments are unreliable. The purpose of this study was to characterize the contribution of Th1 and Th17 cells to the development of optic neuritis. Methods Mice were passively transferred myelin-specific Th1 or Th17 cells to induce experimental autoimmune encephalomyelitis (EAE), a model of neuroautoimmunity. Visual acuity was assessed daily with optokinetic tracking, and 1, 2, and 3 weeks post-induction, optic nerves and retinas were harvested for immunohistochemical analyses. Results Passive transfer experimental autoimmune encephalomyelitis elicits acute episodes of asymmetric visual deficits and is exacerbated in Th17-EAE relative to Th1-EAE. The Th17-EAE optic nerves contained more inflammatory infiltrates and an increased neutrophil to macrophage ratio. Significant geographic degeneration of the retinal ganglion cells accompanied Th17-EAE but not Th1. Conclusions Th17-induced transfer EAE recapitulates pathologies observed in MS-associated optic neuritis, namely, monocular episodes of vision loss, optic nerve inflammation, and geographic retinal ganglion cell (RGC) degeneration. PMID:27122964

  9. Rare combination of bilateral putaminal necrosis, optic neuritis, and polyneuropathy in a case of acute methanol intoxication among patients met with hooch tragedy in Gujarat, India

    PubMed Central

    Jarwani, Bhavesh S; Motiani, Puja; Divetia, Ruchir; Thakkar, Gurudutta

    2012-01-01

    Methanol poisoning is a rare but extremely hazardous form of intoxication, generally occurring after suicidal or accidental events. Methanol is a cheap and potent adulterant of illicit liquors. In India, we have witnessed number of mass emergencies due to adulterated alcohol consumption. Although Gujarat State had banned alcohol consumption since 1961, worse hooch tragedies have often taken place. The most severe consequences of methanol intoxication are blindness, a profound metabolic acidosis and various forms of neurological impairment; which occur characteristically after a latent period of several hours or days after ingestion. We present a unique case of acute methanol intoxication presented with, apart from metabolic acidosis and optic neuritis, involvement of central nervous system and peripheral nervous system. He had bilateral optic neuritis, delayed onset polyneuropathy with axonopathy, and radiculopathy. Magnetic resonance imaging findings were consistent with bilateral putaminal necrosis. PMID:23248510

  10. Eleven episodes of recurrent optic neuritis of the same eye for 22 years eventually diagnosed as neuromyelitis optica spectrum disorder.

    PubMed

    Yew, Yih Chian; Hor, Jyh Yung; Lim, Thien Thien; Kanesalingam, Ruban; Ching, Yee Ming; Arip, Masita; Easaw, P E Samuel; Eow, Gaik Bee

    2016-11-01

    It is difficult to predict whether a particular attack of neuromyelitis optica spectrum disorder (NMOSD) will affect the optic nerve [optic neuritis (ON): unilateral or bilateral], spinal cord (myelitis), brain or brainstem, or a combination of the above. We report an interesting case of recurrent ON of the same eye for a total of 11 episodes in a Chinese woman. Over a period of 22 years, the attacks only involved the left eye, and never the right eye and also no myelitis. For a prolonged duration, she was diagnosed as recurrent idiopathic ON. Only until she was tested positive for aquaporin 4 antibody that her diagnosis was revised to NMOSD. Optical coherence tomography revealed thinning of the retinal nerve fibre layer (RNFL) for the affected left eye, while the RNFL thickness was within normal range for the unaffected right eye. The disability accrual in NMOSD is generally considered to be attack-related - without a clinical attack of ON, there shall be no visual impairment, and no significant subclinical thinning of RNFL. Our case is in agreement with this notion. This is in contrast to multiple sclerosis where subclinical RNFL thinning does occur. This case highlights the importance of revisiting and questioning a diagnosis of recurrent idiopathic ON particularly when new diagnostic tools are available.

  11. Brachial neuritis.

    PubMed

    Dillin, L; Hoaglund, F T; Scheck, M

    1985-07-01

    Brachial neuritis is an unusual syndrome of unknown etiology that can be confused with other causes of pain or weakness, or both, of the shoulder and arm. It is important to distinguish this disorder because of its dramatic symptoms and relatively good prognosis. Sharp pain, usually in the elbow or shoulder, marks the onset of brachial neuritis, but is relatively short-lived. Weakness generally occurs as the pain is subsiding and most frequently involves the deltoid, spinati, serratus anterior, biceps, and triceps. Paresthesias, atrophy, and sensory loss are inconstant features. Electromyographic findings of fibrillation potentials and positive waves characteristically are found in a pattern indicating combined nerve-root and peripheral nerve involvement. Electromyography more frequently than clinical examination shows that the lesion is bilateral, and also is of both diagnostic and prognostic value. Other laboratory studies serve only to exclude other causes of shoulder pain. The clinical course is variable, but in 90 per cent of patients complete recovery occurs within three years. Recurrences are uncommon.

  12. Chromatic discrimination losses in multiple sclerosis patients with and without optic neuritis using the Cambridge Colour Test.

    PubMed

    Moura, Ana Laura de Araújo; Teixeira, Rosani Aparecida Antunes; Oiwa, Nestor N; Costa, Marcelo F; Feitosa-Santana, Claudia; Callegaro, Dagoberto; Hamer, Russell D; Ventura, Dora Fix

    2008-01-01

    We assessed chromatic discrimination in multiple sclerosis (MS) patients both with (ON) and without (no ON) a history of optic neuritis using the Cambridge color test (CCT). Our goal was to determine the magnitude and chromatic axes of any color vision losses in both patient groups, and to evaluate age-related changes in chromatic discrimination in both patient groups compared to normals. Using the CCT, we measured chromatic discrimination along the protan, deutan and tritan axes in 35 patients with MS (17 ON eyes) and 74 age matched controls. Color thresholds for both patient groups were significantly higher than controls' along the protan and tritan axes (p < 0.001). In addition, the ON and no-ON groups differed significantly along all three-color axes (p < 0.001). MS patients presented a progressive color discrimination impairment with age (along the deutan and tritan axes) that was almost two times faster than controls, even in the absence of ON. These findings suggest that demyelinating diseases reduce sensitivity to color vision in both red-green and blue-yellow axes, implying impairment in both parvocellular and koniocellular visual pathways. The CCT is a useful tool to help characterize vision losses in MS, and the relationship between these losses and degree of optic nerve involvement.

  13. Occurrence of Asymptomatic Acute Neuromyelitis Optica Spectrum Disorder-Typical Brain Lesions during an Attack of Optic Neuritis or Myelitis

    PubMed Central

    Kim, Su-Hyun; Hyun, Jae-Won; Joung, AeRan; Lee, Sang Hyun; Kim, Ho Jin

    2016-01-01

    We aimed to investigate the frequency of asymptomatic acute brain MRI abnormalities accompanying optic neuritis (ON) or myelitis in neuromyelitis optica spectrum disorder (NMOSD) patients with aquaporin-4 antibodies (AQP4-Ab). We reviewed 324 brain MRI scans that were obtained during acute attacks of ON or myelitis, in 165 NMOSD patients with AQP4-Ab. We observed that acute asymptomatic NMOSD-typical brain lesions accompanied 27 (8%) acute attacks of ON or myelitis in 24 (15%) patients. The most common asymptomatic brain abnormalities included edematous corpus callosum lesions (n = 17), followed by lesions on the internal capsule and/or cerebral peduncle lesions (n = 9), periependymal surfaces of the fourth ventricle (n = 5), large deep white matter lesions (n = 4), periependymal cerebral lesions surrounding the lateral ventricles (n = 3), and hypothalamic lesions (n = 1). If asymptomatic NMOSD-typical brain abnormalities were considered as evidence for DIS, while also assuming that the AQP4-IgG status was unknown, the median time to diagnosis using the 2015 diagnosis criteria for NMOSD was shortened from 28 months to 6 months (p = 0.008). Asymptomatic acute NMOSD-typical brain lesions can be accompanied by an acute attack of ON or myelitis. Identifying these asymptomatic brain lesions may help facilitate earlier diagnosis of NMOSD. PMID:27936193

  14. Occurrence of Asymptomatic Acute Neuromyelitis Optica Spectrum Disorder-Typical Brain Lesions during an Attack of Optic Neuritis or Myelitis.

    PubMed

    Kim, Su-Hyun; Hyun, Jae-Won; Joung, AeRan; Lee, Sang Hyun; Kim, Ho Jin

    2016-01-01

    We aimed to investigate the frequency of asymptomatic acute brain MRI abnormalities accompanying optic neuritis (ON) or myelitis in neuromyelitis optica spectrum disorder (NMOSD) patients with aquaporin-4 antibodies (AQP4-Ab). We reviewed 324 brain MRI scans that were obtained during acute attacks of ON or myelitis, in 165 NMOSD patients with AQP4-Ab. We observed that acute asymptomatic NMOSD-typical brain lesions accompanied 27 (8%) acute attacks of ON or myelitis in 24 (15%) patients. The most common asymptomatic brain abnormalities included edematous corpus callosum lesions (n = 17), followed by lesions on the internal capsule and/or cerebral peduncle lesions (n = 9), periependymal surfaces of the fourth ventricle (n = 5), large deep white matter lesions (n = 4), periependymal cerebral lesions surrounding the lateral ventricles (n = 3), and hypothalamic lesions (n = 1). If asymptomatic NMOSD-typical brain abnormalities were considered as evidence for DIS, while also assuming that the AQP4-IgG status was unknown, the median time to diagnosis using the 2015 diagnosis criteria for NMOSD was shortened from 28 months to 6 months (p = 0.008). Asymptomatic acute NMOSD-typical brain lesions can be accompanied by an acute attack of ON or myelitis. Identifying these asymptomatic brain lesions may help facilitate earlier diagnosis of NMOSD.

  15. [Isolated functional loss of the lateral semicircular canal in vestibular neuritis].

    PubMed

    Blödow, A; Helbig, R; Bloching, M; Walther, L E

    2013-01-01

    Today, modern tools in vestibular testing are feasible to provide information about functional status of all five peripheral vestibular receptors. Isolated or combined loss of crista and macula receptor function can be determined in the diagnostic process. We describe a seldom case of isolated functional loss of lateral semicircular canal receptor function in a 55-year-old patient. Whereas there was no ispilateral caloric response and video head impulse test revealed a catch-up saccade, air-conducted (AC) cervical and ocular vestibular-evoked myogenic potentials (cVEMP, oVEMP), subjective visual vertical and MRI were normal.

  16. Impact of the anti-aquaporin-4 autoantibody on inner retinal structure, function and structure-function associations in Japanese patients with optic neuritis

    PubMed Central

    Matsumoto, Yoshiko; Mori, Sotaro; Ueda, Kaori; Kurimoto, Takuji; Kanamori, Akiyasu; Yamada, Yuko; Nakashima, Ichiro

    2017-01-01

    Purpose An autoantibody against aquaporin-4 (AQP4 Ab) is highly specific for neuromyelitis optica spectrum disorder and plays a pathogenic role in this disease. The purpose of this study was to investigate the impact of AQP4 Ab on inner retinal structure, function, and the structure−function relationships in eyes with optic neuritis. Methods Thirty five eyes from 25 cases who had received visual function tests and RTVue optical coherence tomography (OCT) measurement at least six months after the latest episode of optic neuritis were enrolled. Patients with multiple sclerosis were excluded. AQP4 Ab was measured using a cell-based assay. Visual acuity, mean deviation (MD) of the Humphrey visual field SITA standard 30–2 tests, retinal nerve fiber layer (RNFL), ganglion cell complex (GCC) thicknesses, and other clinical variables were compared between the AQP4 Ab-positive and -negative groups. Parameters associated with visual functions were evaluated by generalized estimating equation (GEE) models. Results The AQP4 Ab-positive group (20 eyes from 12 cases) had a higher proportion of bilateral involvement and longer duration of follow-up than the AQP4 Ab-negative group (15 eyes from 13 cases). Linear mixed effect models revealed worse MD and visual acuity in AQP4 Ab-positive eyes than those in AQP4 Ab-negative eyes after adjusting for within-patient inter-eye dependence, whereas there were no differences in RNFL and GCC thickness between the two groups. In seropositive eyes, GEE regression analyses revealed that depending on age and the number of recurrences of ON episodes, OCT parameters correlated strongly with MD and more weakly with visual acuity. Conclusions Reductions in RNFL and GCC thickness were proportional to the visual field defect in eyes with AQP4 Ab but not in eyes without AQP4 Ab. The presence of AQP4 Ab probably plays a critical role in retinal ganglion cell loss in optic neuritis. PMID:28199381

  17. Altered intrinsic regional spontaneous brain activity in patients with optic neuritis: a resting-state functional magnetic resonance imaging study

    PubMed Central

    Shao, Yi; Cai, Feng-Qin; Zhong, Yu-Lin; Huang, Xin; Zhang, Ying; Hu, Pei-Hong; Pei, Chong-Gang; Zhou, Fu-Qing; Zeng, Xian-Jun

    2015-01-01

    Objective To investigate the underlying regional homogeneity (ReHo) in brain-activity deficit in patients with optic neuritis (ON) and its relationship with behavioral performance. Materials and methods In total, twelve patients with ON (four males and eight females) and twelve (four males and eight females) age-, sex-, and education-matched healthy controls underwent resting-state functional magnetic resonance imaging scans. The ReHo method was used to assess the local features of spontaneous brain activity. Correlation analysis was used to explore the relationship between the observed mean ReHo values of the different brain areas and the visual evoked potential (VEP) in patients with ON. Results Compared with the healthy controls, patients with ON showed lower ReHo in the left cerebellum, posterior lobe, left middle temporal gyrus, right insula, right superior temporal gyrus, left middle frontal gyrus, bilateral anterior cingulate cortex, left superior frontal gyrus, right superior frontal gyrus, and right precentral gyrus, and higher ReHo in the cluster of the left fusiform gyrus and right inferior parietal lobule. Meanwhile, we found that the VEP amplitude of the right eye in patients with ON showed a positive correlation with the ReHo signal value of the left cerebellum posterior lobe (r=0.701, P=0.011), the right superior frontal gyrus (r=0.731, P=0.007), and the left fusiform gyrus (r=0.644, P=0.024). We also found that the VEP latency of the right eye in ON showed a positive correlation with the ReHo signal value of the right insula (r=0.595, P=0.041). Conclusion ON may involve dysfunction in the default-mode network, which may reflect the underlying pathologic mechanism. PMID:26715848

  18. Adeno-Associated Viral-Mediated Catalase Expression Suppresses Optic Neuritis in Experimental Allergic Encephalomyelitis

    NASA Astrophysics Data System (ADS)

    Guy, John; Qi, Xiaoping; Hauswirth, William W.

    1998-11-01

    Suppression of oxidative injury by viral-mediated transfer of the human catalase gene was tested in the optic nerves of animals with experimental allergic encephalomyelitis (EAE). EAE is an inflammatory autoimmune disorder of primary central nervous system demyelination that has been frequently used as an animal model for the human disease multiple sclerosis (MS). The optic nerve is a frequent site of involvement common to both EAE and MS. Recombinant adeno-associated virus containing the human gene for catalase was injected over the right optic nerve heads of SJL/J mice that were simultaneously sensitized for EAE. After 1 month, cell-specific catalase activity, evaluated by quantitation of catalase immunogold, was increased approximately 2-fold each in endothelia, oligodendroglia, astrocytes, and axons of the optic nerve. Effects of catalase on the histologic lesions of EAE were measured by computerized analysis of the myelin sheath area (for demyelination), optic disc area (for optic nerve head swelling), extent of the cellular infiltrate, extravasated serum albumin labeled by immunogold (for blood-brain barrier disruption), and in vivo H2O2 reaction product. Relative to control, contralateral optic nerves injected with the recombinant virus without a therapeutic gene, catalase gene inoculation reduced demyelination by 38%, optic nerve head swelling by 29%, cellular infiltration by 34%, disruption of the blood-brain barrier by 64%, and in vivo levels of H2O2 by 61%. Because the efficacy of potential treatments for MS are usually initially tested in the EAE animal model, this study suggests that catalase gene delivery by using viral vectors may be a therapeutic strategy for suppression of MS.

  19. Relationship between Optical Coherence Tomography and Electrophysiology of the Visual Pathway in Non-Optic Neuritis Eyes of Multiple Sclerosis Patients

    PubMed Central

    Sriram, Prema; Wang, Chenyu; Yiannikas, Con; Garrick, Raymond; Barnett, Michael; Parratt, John; Graham, Stuart L.; Arvind, Hemamalini; Klistorner, Alexander

    2014-01-01

    Purpose Loss of retinal ganglion cells in in non-optic neuritis eyes of Multiple Sclerosis patients (MS-NON) has recently been demonstrated. However, the pathological basis of this loss at present is not clear. Therefore, the aim of the current study was to investigate associations of clinical (high and low contrast visual acuity) and electrophysiological (electroretinogram and multifocal Visual Evoked Potentials) measures of the visual pathway with neuronal and axonal loss of RGC in order to better understand the nature of this loss. Methods Sixty-two patients with relapsing remitting multiple sclerosis with no previous history of optic neuritis in at least one eye were enrolled. All patients underwent a detailed ophthalmological examination in addition to low contrast visual acuity, Optical Coherence Tomography, full field electroretinogram (ERG) and multifocal visual evoked potentials (mfVEP). Results There was significant reduction of ganglion cell layer thickness, and total and temporal retinal nerve fibre layer (RNFL) thickness (p<0.0001, 0.002 and 0.0002 respectively). Multifocal VEP also demonstrated significant amplitude reduction and latency delay (p<0.0001 for both). Ganglion cell layer thickness, total and temporal RNFL thickness inversely correlated with mfVEP latency (r = −0.48, p<0.0001 respectively; r = −0.53, p<0.0001 and r = −0.59, p<0.0001 respectively). Ganglion cell layer thickness, total and temporal RNFL thickness also inversely correlated with the photopic b-wave latency (r = −0.35, p = 0.01; r = −0.33, p = 0.025; r = −0.36, p = 0.008 respectively). Multivariate linear regression model demonstrated that while both factors were significantly associated with RGC axonal and neuronal loss, the estimated predictive power of the posterior visual pathway damage was considerably larger compare to retinal dysfunction. Conclusion The results of our study demonstrated significant association of RGC axonal

  20. Compact optical isolator.

    PubMed

    Sansalone, F J

    1971-10-01

    This paper describes a compact Faraday rotation isolator using terbium aluminum garnet (TAG) as the Faraday rotation material and small high field permanent magnets made of copper-rare earth alloys. The nominal isolation is 26 dB with a 0.4-dB forward loss. The present isolator can be adjusted to provide effective isolation from 4880 A to 5145 A. Details of the design, fabrication, and performance of the isolator are presented.

  1. Structural Alterations of Segmented Macular Inner Layers in Aquaporin4-Antibody-Positive Optic Neuritis Patients in a Chinese Population

    PubMed Central

    Peng, Chunxia; Wang, Wei; Xu, Quangang; Zhao, Shuo; Li, Hongyang; Yang, Mo; Cao, Shanshan; Zhou, Huanfen; Wei, Shihui

    2016-01-01

    Objectives This study aimed to analyse the structural injury of the peripapillary retinal nerve fibre layer (pRNFL) and segmented macular layers in optic neuritis (ON) in aquaporin4-antibody (AQP4-Ab) seropositivity(AQP4-Ab-positiveON) patients and in AQP4-Ab seronegativity (AQP4-Ab-negative ON) patients in order to evaluate their correlations with the best-corrected visual acuity (BCVA) and the value of the early diagnosis of neuromyelitis optica (NMO). Design This is a retrospective, cross-sectional and control observational study. Methods In total, 213 ON patients (291 eyes) and 50 healthy controls (HC) (100 eyes) were recruited in this study. According to a serum AQP4-Ab assay, 98 ON patients (132 eyes) were grouped as AQP4-Ab-positive ON and 115 ON patients (159 eyes) were grouped as AQP4-Ab-negative ON cohorts. All subjects underwent scanning with spectralis optical coherence tomography (OCT) and BCVA tests. pRNFL and segmented macular layer measurements were analysed. Results The pRNFL thickness in AQP4-Ab-positive ON eyes showed a more serious loss during 0–2 months (-27.61μm versus -14.47 μm) and ≥6 months (-57.91μm versus -47.19μm) when compared with AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON preferentially damaged the nasal lateral pRNFL. The alterations in the macular ganglion cell layer plus the inner plexiform layer (GCIP) in AQP4-Ab-positive ON eyes were similar to those in AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON eyes had entirely different injury patterns in the inner nuclear layer (INL) compared with AQP4-Ab-negative ON eyes during the first 6 months after the initial ON attack. These differences were as follows: the INL volume of AQP4-Ab-positive ON eyes had a gradual growing trend compared with AQP4-Ab-negative ON eyes, and it increased rapidly during 0–2 months, reached its peak during 2–4 months, and then decreased gradually. The pRNFL and GCIP in AQP4-Ab-positive ON eyes had positive correlations with BCVA. When the p

  2. Adding Papillomacular Bundle Measurements to Standard Optical Coherence Tomography Does Not Increase Sensitivity to Detect Prior Optic Neuritis in Patients with Multiple Sclerosis

    PubMed Central

    Laible, Mona; Jarius, Sven; Schmidt-Bacher, Annette; Platten, Michael; Haas, Jürgen

    2016-01-01

    Purpose To improve the detection of retinal nerve fiber layer (RNFL) thinning in multiple sclerosis (MS), a special peripapillary ring scanning algorithm (N-site RNFL, N-RNFL) was developed for spectral domain optical coherence tomography (SD-OCT). In contrast to the standard protocol (ST-RNFL) scanning starts nasally, not temporally, and provides an additional sector of analysis, the papillomacular bundle (PMB). We aimed to ascertain whether the temporal RNFL differs between the two techniques, whether N-RNFL is more sensitive than ST-RNFL to detect previous optic neuritis (ON), and whether analyzing the PMB adds additional sensitivity. Furthermore, we investigated whether RNFL is associated with disease severity and/or disease duration. Methods We conducted a cross-sectional case-control study of 38 patients with MS, of whom 24 had a history of ON, and 40 healthy controls (HC). Subjects with ON within the previous 6 months were excluded. Records included clinical characteristics, visual evoked potentials (VEP), and SD-OCT in both techniques. Results In a total of 73 evaluable MS eyes, temporal N-RNFL was abnormal in 17.8%, temporal ST-RNFL in 19.2%, and the PMB-RNFL in 21.9%. In ON eyes, the sensitivity of temporal N-RNFL and ST-RNFL did not differ significantly (37.0%/33.3%, p = 0.556). The sensitivity of VEP was 85.2%. RNFL thickness was associated with disease severity in all eyes, with and without a history of ON, and with disease duration. Conclusion The two OCT techniques detected previous ON with similar sensitivity, but the sensitivity of VEPs was superior to that of both N-RNFL and ST-RNFL. Our results indicate that the widely used ST-RNFL technique is appropriate for peripapillary RNFL measurements in MS patients. PMID:27171375

  3. Inferior vestibular neuritis.

    PubMed

    Kim, Ji-Soo; Kim, Hyo Jung

    2012-08-01

    Vestibular neuritis (VN) mostly involves the superior portion of the vestibular nerve and labyrinth. This study aimed to describe the clinical features of VN involving the inferior vestibular labyrinth and its afferents only. Of the 703 patients with a diagnosis of VN or labyrinthitis at Seoul National University Bundang Hospital from 2004 to 2010, we retrospectively recruited 9 patients (6 women, age range 15-75) with a diagnosis of isolated inferior VN. Diagnosis of isolated inferior VN was based on torsional downbeating spontaneous nystagmus, abnormal head-impulse test (HIT) for the posterior semicircular canal (PC), and abnormal cervical vestibular-evoked myogenic potentials (VEMP) in the presence of normally functioning horizontal and anterior semicircular canals, as determined by normal HIT and bithermal caloric tests. All patients presented with acute vertigo with nausea, vomiting, and imbalance. Three patients also had tinnitus and hearing loss in the involved side. The rotation axis of torsional downbeating spontaneous nystagmus was best aligned with that of the involved PC. HIT was also positive only for the involved PC. Cervical VEMP was abnormal in seven patients, and ocular VEMP was normal in all four patients tested. Ocular torsion and subjective visual vertical tests were mostly within the normal range. Since isolated inferior VN lacks the typical findings of much more prevalent superior VN, it may be mistaken for a central vestibular disorder. Recognition of this rare disorder may help avoid unnecessary workups in patients with acute vestibulopathy.

  4. Persistent presence of the anti-myelin oligodendrocyte glycoprotein autoantibody in a pediatric case of acute disseminated encephalomyelitis followed by optic neuritis.

    PubMed

    Miyauchi, Akihiko; Monden, Yukifumi; Watanabe, Meri; Sugie, Hideo; Morita, Mitsuya; Kezuka, Takeshi; Momoi, Mariko; Yamagata, Takanori

    2014-06-01

    We report the case of a 5-year-old Japanese girl who initially had acute disseminated encephalomyelitis (ADEM) and was positive for the myelin oligodendrocyte glycoprotein (MOG) antibodies and developed unilateral optic neuritis (ON) 71 days after ADEM onset. The patient's serum was positive for the anti-MOG antibodies from the onset of ADEM to the development of ON. This phenotype has been reported in only two previous articles, and the specific mechanism of action of the anti-MOG antibodies is not yet understood. Our case suggests that the anti-MOG antibody can be associated with the pathogenesis of ADEM followed by ON. Thus, patients with ADEM who test positive for the anti-MOG antibody may be at risk of developing subsequent ON.

  5. Efficient broadband composite optical isolator.

    PubMed

    St Dimova, E; Comparat, D; Popkirov, G St; Rangelov, A A; Vitanov, N V

    2013-12-10

    A new design of a broadband optical isolator, composed as a sequence of ordinary Faraday rotators and achromatic quarter-wave plates (QWPs), is presented. In particular, we demonstrate that by using four Faraday rotators and six achromatic QWPs, rotated at specific angles, optical isolation better than 15 dB over the range from 700 to 1000 nm can be achieved. The measured transmittance (corrected for absorption and reflection) in the forward direction over the same wavelength range shows broadening of the transmission spectrum compared with the one of a single Faraday rotator.

  6. Power inverter with optical isolation

    DOEpatents

    Duncan, Paul G.; Schroeder, John Alan

    2005-12-06

    An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

  7. Combined brain and anterior visual pathways' MRIs assist in early identification of neuromyelitis optica spectrum disorder at onset of optic neuritis.

    PubMed

    Buch, D; Savatovsky, J; Gout, O; Vignal, C; Deschamps, R

    2017-03-01

    Acute optic neuritis (ON) is the initial presentation in half of neuromyelitis optica spectrum disorder (NMO-SD) cases. Our objective was to evaluate accuracy of combined MRIs of the anterior visual pathways and of the brain to correctly identify NMO-SD among patients with acute ON. We performed a retrospective study on patients with acute ON in NMO-SD (16 episodes) and first-event non-NMO-SD (32 episodes). All MRIs included exams of the brain and anterior visual pathways using T2-weighted and post-gadolinium T1-weighted coronal thin slices. Images were reviewed by a neuroradiologist who was blinded to the final diagnosis. There were no multiple sclerosis (MS)-like lesions with dissemination in space (DIS) with NMO-SD (0 vs. 53%, p < 0.01). Non-NMO-SD ON usually spared the chiasma (3 vs. 44%, p < 0.01) and the optic tracts (0 vs. 19%, p < 0.01). Optic nerve lesions were longer [median (range) 26 mm (14-64) vs. 13 mm [8-36], p < 0.01] and the number of segments involved higher (3 [1-8] vs. 1 [1-4], p < 0.01) in NMO-SD. Bilateral optic nerve involvement, or involvement of ≥3 segments, or involvement of the chiasma, or optic tracts in the absence of MS-like lesions with DIS were suggestive of NMO-SD with a sensitivity of 69% (CI 95% 41-89) and a specificity of 97% (CI 95% 84-99) (p < 0.01). Combining brain and anterior visual pathways' MRIs seems efficient for detecting acute ON patients who are at high risk for NMO-SD.

  8. Low-loss, high-isolation, fiber-optic isolator

    NASA Technical Reports Server (NTRS)

    Lutes, George F. (Inventor)

    1988-01-01

    A low-loss, high-isolation, fiber-optic isolator for use in single-mode fiber systems utilizes a Faraday rotator and two polarizers, one at each end angularly oriented from each other at the angle of rotation for isolation, and two aspheric lens connectors to couple optical fibers to the Faraday isolator to reduce forward loss to about 2.5 dB and improve isolation to greater than 70 dB.

  9. Optical isolator system for fiber-optic uses

    NASA Technical Reports Server (NTRS)

    Lutes, George

    1988-01-01

    A low loss optical isolator suitable for fiber-optic uses has been assembled from commercial components. The isolator exhibits reverse isolation of greater than 70 dB, with a forward loss of less than 1.3dB. This system provides an effective approach for reducing instabilities encountered in the output signal of semiconductor lasers in certain applications of fiber-optic systems. The paper presents a phenomenological explanation for the superior performance of the isolator system.

  10. Optical isolator system for fiber-optic uses.

    PubMed

    Lutes, G

    1988-04-01

    A low loss optical isolator suitable for fiber-optic uses has been assembled from commercial components. The isolator exhibits reverse isolation of >70 dB, with a forward loss of <1.3 dB. This system provides an effective approach for reducing instabilities encountered in the output signal of semiconductor lasers in certain applications of fiber-optic systems. The paper presents a phenomenological explanation for the superior performance of the isolator system.

  11. White and Gray Matter Volume Changes and Correlation with Visual Evoked Potential in Patients with Optic Neuritis: A Voxel-Based Morphometry Study

    PubMed Central

    Huang, Xin; Zhang, Qiang; Hu, Pei-Hong; Zhong, Yu-Lin; Zhang, Ying; Wei, Rong; Xu, Ting-Ting; Shao, Yi

    2016-01-01

    Background The aim of this study was to investigate potential morphological alterations of gray and white matter in patients with optic neuritis (ON) and their relationship with behavioral performance, using voxel-based morphometry (VBM). Material/Methods Twelve (4 males, 8 females) patients with ON and 12 (4 males, 8 females) age-, sex-, and education-matched healthy controls (HCs) underwent magnetic resonance imaging (MRI). Imaging data were analyzed using two-sample t tests to identify group differences in gray and white matter volume (GMV, WMV). Correlation analysis was used to explore relationships between observed GMV and WMV of different areas and visual evoked potential (VEP) in ON. Results Compared with HCs, ON patients had: significantly decreased GMV in the left postcentral gyrus, left inferior frontal gyrus, left anterior cingulate, left and right middle frontal gyrus, and right inferior parietal lobule; decreased WMV in the left middle frontal gyrus, right superior frontal gyrus, left precentral gyrus and right inferior parietal lobule; and increased WMV in the left fusiform gyrus and left inferior parietal lobule. VEP latency of the right eye in ON correlated positively with WMV signal value of the left fusiform gyrus (r=0.726, p=0.008), and negatively with GMV signal value of the right inferior parietal lobule (r=−0.611, p=0.035). Duration of ON correlated negatively with WMV signal value of the right superior frontal gyrus (r=−0.662, p=0.019), while best-corrected visual acuity (VA) of the right eye correlated negatively with WMV signal value of the left middle frontal gyrus (r=−0.704, p=0.011). Conclusions These results suggest significant brain involvement in ON, which may reflect the underlying pathologic mechanism. Correlational results demonstrate that VEP in ON is closely associated with WMV and GMV atrophy in many brain regions. PMID:27045330

  12. Disturbed spontaneous brain-activity pattern in patients with optic neuritis using amplitude of low-frequency fluctuation: a functional magnetic resonance imaging study

    PubMed Central

    Huang, Xin; Cai, Feng-Qin; Hu, Pei-Hong; Zhong, Yu-Lin; Zhang, Ying; Wei, Rong; Pei, Chong-Gang; Zhou, Fu-Qing; Shao, Yi

    2015-01-01

    Objective To use the amplitude of low-frequency fluctuation (ALFF) technique to investigate the local features of spontaneous brain activity in optic neuritis (ON) and their relationship with behavioral performance. Materials and methods Twelve patients with ON (four male, eight female) and twelve age-, sex-, and education status-matched healthy controls (HCs) (four male, eight female) underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans. The ALFF technique was used to assess local features of spontaneous brain activity. Correlation analysis was used to explore the relationship between the observed mean ALFF values of the different areas and visual evoked potentials (VEPs) in patients with ON. Results Compared with HCs, patients with ON had significantly decreased ALFF values in the posterior and anterior lobes of the right cerebellum, right putamen, right inferior frontal gyrus, right insula, right supramarginal gyrus, right inferior parietal lobule, left medial frontal gyrus, left superior temporal gyrus, bilateral anterior cingulate/medial frontal gyrus, and bilateral precuneus, and significantly increased ALFF values in the posterior lobes of the left and right cerebellum, right inferior temporal gyrus, right inferior temporal/fusiform gyrus, left parahippocampal gyrus, left fusiform gyrus, left calcarine fissure, left inferior parietal lobule, and left cuneus. We found negative correlations between the mean ALFF signal value of the left parahippocampal gyrus and the VEP amplitude of the right eye in ON (r=−0.584, P=0.046), and a positive correlation between the mean ALFF signal value of the bilateral precuneus and the best-corrected visual acuity of the left eye (r=0.579, P=0.048) in patients with ON. Conclusion ON mainly seems to involve dysfunction in the default-mode network, cerebellum, and limbic system, which may reflect the underlying pathologic mechanism of ON. PMID:26719692

  13. Brain Tissue Volumes and Perfusion Change with the Number of Optic Neuritis Attacks in Relapsing Neuromyelitis Optica: A Voxel-Based Correlation Study.

    PubMed

    Sánchez-Catasús, Carlos A; Cabrera-Gomez, José; Almaguer Melián, William; Giroud Benítez, José Luis; Rodríguez Rojas, Rafael; Bayard, Jorge Bosch; Galán, Lídice; Sánchez, Reinaldo Galvizu; Fuentes, Nancy Pavón; Valdes-Sosa, Pedro

    2013-01-01

    Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO) are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO) is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV) and grey matter volumes (GMV) and/or perfusion on one side, and the number of optic neuritis (ON) attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO.

  14. Optical isolator for semiconductor lasers.

    PubMed

    Kuwahara, H

    1980-01-15

    An optical isolator for semiconductor lasers, consisting of a polarizer and a quarterwave plate, was investigated experimentally. It was assembled in a compact laser-to-fiber coupling module. Experiment showed forward loss of 1.15 dB, backward loss of 24.8 dB, and rotative tolerance of 2.4 deg for 1 dB down. The length of the module is 43.2 mm. The coupling efficiency to a graded-index multimode fiber is 37.5%. The extinction ratio is improved by 6.75 dB. The suppression effect on the influence of reflected light was investigated, using the assembled module.

  15. Retinal Nerve Fiber Layer May Be Better Preserved in MOG-IgG versus AQP4-IgG Optic Neuritis: A Cohort Study

    PubMed Central

    Chodick, Gabriel; Bialer, Omer; Marignier, Romain; Bach, Michael; Hellmann, Mark Andrew

    2017-01-01

    Background Optic neuritis (ON) in patients with anti-myelin oligodendrocyte glycoprotein (MOG)-IgG antibodies has been associated with a better clinical outcome than anti-aquaporin 4 (AQP4)- IgG ON. Average retinal nerve fiber layer thickness (RNFL) correlates with visual outcome after ON. Objectives The aim of this study was to examine whether anti-MOG-IgG ON is associated with better average RNFL compared to anti-AQP4-IgG ON, and whether this corresponds with a better visual outcome. Methods A retrospective study was done in a consecutive cohort of patients following anti-AQP4-IgG and anti-MOG-IgG ON. A generalized estimating equation (GEE) models analysis was used to compare average RNFL outcomes in ON eyes of patients with MOG-IgG to AQP4-IgG-positive patients, after adjusting for the number of ON events. The final mean visual field defect and visual acuity were compared between ON eyes of MOG-IgG and AQP4-IgG-positive patients. A correlation between average RNFL and visual function was performed in all study eyes. Results Sixteen patients were analyzed; ten AQP4-IgG-positive and six MOG-IgG-positive. The six patients with MOG-IgG had ten ON events with disc edema, five of which were bilateral. In the AQP4-IgG-positive ON events, 1/10 patients had disc edema. Final average RNFL was significantly better in eyes following MOG-IgG-ON (75.33μm), compared to 63.63μm in AQP4-IgG-ON, after adjusting for the number of ON attacks (GEE, p = 0.023). Mean visual field defects were significantly smaller (GEE, p = 0.046) among MOG-IgG positive ON eyes compared to AQP-IgG positive ON eyes, but last visual acuity did not differ between the groups (GEE, p = 0.153). Among all eyes, average RNFL positively correlated with mean visual field defect (GEE, p = 0.00015) and negatively correlated with final visual acuity (GEE, p = 0.00005). Conclusions Following ON, RNFL is better preserved in eyes of patients with MOG-IgG antibodies compared to those with AQP4-IgG antibodies

  16. Linear and passive silicon optical isolator.

    PubMed

    Wang, Chen; Zhong, Xiao-Lan; Li, Zhi-Yuan

    2012-01-01

    On-chip optical isolation plays a key role in optical communications and computing based on silicon integrated photonic structures and has attracted great attentions for long years. Recently there have appeared hot controversies upon whether isolation of light can be realized via linear and passive photonic structures. Here we demonstrate optical isolation of infrared light in purely linear and passive silicon photonic structures. Both numerical simulations and experimental measurements show that the round-trip transmissivity of in-plane infrared light across a silicon photonic crystal slab heterojunction diode could be two orders of magnitudes smaller than the forward transmissivity at around 1,550 nm with a bandwidth of about 50 nm, indicating good performance of optical isolation. The occurrence of in-plane light isolation is attributed to the information dissipation due to off-plane and side-way scattering and selective modal conversion in the multiple-channel structure and has no conflict with the reciprocal principle.

  17. Visible optical isolator using ZnSe.

    PubMed

    Wunderlich, J A; Deshazer, L G

    1977-06-01

    A compact Faraday effect optical isolator was constructed for visible wavelengths and tested at 5145 A. The nonreciprocal element of the isolator was polycrystalline zinc selenide placed in the magnetic field of a permanent magnet. For 5145 A the isolator had a 2.06-dB insertion loss and a 25.5-dB isolation. Indices of refraction and Verdet constants were measured for zinc selenide in the wavelengthregion from 4700 to 6300 A.

  18. Visible optical isolator using ZnSe

    NASA Technical Reports Server (NTRS)

    Wunderlich, J. A.; Deshazer, L. G.

    1977-01-01

    A compact Faraday effect optical isolator was constructed for visible wavelengths and tested at 5145 A. The nonreciprocal element of the isolator was polycrystalline zinc selenide placed in the magnetic field of a permanent magnet. For 5145 A the isolator had a 2.06-dB insertion loss and a 25.5-dB isolation. Indices of refraction and Verdet constants were measured for zinc selenide in the wavelength region from 4700 to 6300 A.

  19. [Vestibular neuritis: treatment and prognosis].

    PubMed

    Reinhard, A; Maire, R

    2013-10-02

    Vestibular neuritis is a sudden unilateral peripheral vestibular deficit of unknown origin without associated hearing loss. It is the second cause of peripheral vertigo after Benign Paroxysmal Positional Vertigo (BPPV). The etiology remains unclear and some treatments are still controversial. The prognosis is good. The differential diagnosis of the disease mainly includes an acute vertigo of central origin. This article summarizes the management and prognosis of vestibular neuritis.

  20. Optical Isolators With Transverse Magnets

    NASA Technical Reports Server (NTRS)

    Fan, Yuan X.; Byer, Robert L.

    1991-01-01

    New design for isolator includes zigzag, forward-and-backward-pass beam path and use of transverse rather than longitudinal magnetic field. Design choices produce isolator with as large an aperture as desired using low-Verdet-constant glass rather than more expensive crystals. Uses commercially available permanent magnets in Faraday rotator. More compact and less expensive. Designed to transmit rectangular beam. Square cross section of beam extended to rectangular shape by increasing one dimension of glass without having to increase magnetic field. Potentially useful in laser systems involving slab lasers and amplifiers. Has applications to study of very-high-power lasers for fusion research.

  1. Diagnosis and classification of autoimmune optic neuropathy.

    PubMed

    Petzold, Axel; Plant, Gordon T

    2014-01-01

    The spectrum of autoimmune optic neuropathies (ON) is extending. The phenotypic spectrum includes single isolated optic neuritis (SION), relapsing isolated optic neuritis (RION), chronic relapsing inflammatory optic neuropathy (CRION), the neuromyelitis optica (NMO) spectrum disorder, multiple sclerosis associated optic neuritis (MSON) and unclassified optic neuritis (UCON) forms. Epidemiological data suggests a slight female predominance. The ethnic heritage is relevant as Caucasian patients are more likely to suffer from MSON, whilst SION, RION, CRION and NMO are more frequent in non-Caucasian patients. Importantly, prognosis for recovery of visual function is good in MSON, but poorer in NMO and CRION which also have a high chance for recurrent episodes. Testing for serum anti-AQP4 autoantibodies is advised in all patients with severe, atypical or recurrent ON because of the high diagnostic specificity. The diagnostic specificity may be aided by testing for glial biomarkers in the CSF and prognostic accuracy by testing for biomarkers for neuroaxonal degeneration. Optical coherence tomography is a highly accurate tool to document the final outcome. The current clinical classification criteria rely on the phenotype, response to treatment and presence of anti-AQP4 autoantibodies.

  2. Broadband optical isolator based on helical metamaterials.

    PubMed

    Cao, Hu; Yang, ZhenYu; Zhao, Ming; Wu, Lin; Zhang, Peng

    2015-05-01

    Based on helical metamaterials, a new broadband optical isolator with a triple-helix structure is proposed in this paper. The right-handed circularly polarized light can transmit through the isolator with its polarization unchanged. The reverse propagating light, which is caused by the reflection of the latter optical devices, is converted into left-handed circularly polarized light that is suppressed by the proposed isolator because of absorption. Our design has some unprecedented advantages such as broad frequency ranges and a compact structure; moreover, neither polarizers nor adscititious magnetic fields are required. Properties of the isolator are investigated using the finite-difference time-domain method, and this phenomenon is studied by the mechanism of helical antenna theory.

  3. Optical isolation via unidirectional resonant photon tunneling

    SciTech Connect

    Moccia, Massimo; Castaldi, Giuseppe; Galdi, Vincenzo; Alù, Andrea; Engheta, Nader

    2014-01-28

    We show that tri-layer structures combining epsilon-negative and magneto-optical material layers can exhibit unidirectional resonant photon tunneling phenomena that can discriminate between circularly polarized (CP) waves of given handedness impinging from opposite directions, or between CP waves with different handedness impinging from the same direction. This physical principle, which can also be interpreted in terms of a Fabry-Perot-type resonance, may be utilized to design compact optical isolators for CP waves. Within this framework, we derive simple analytical conditions and design formulae, and quantitatively assess the isolation performance, also taking into account the unavoidable imperfections and nonidealities.

  4. Optical isolator using two tandem phase modulators.

    PubMed

    Doerr, Christopher R; Dupuis, Nicolas; Zhang, Liming

    2011-11-01

    We propose and demonstrate an integrated optical isolator in InP using two phase modulators in series. The phase modulators are driven with a single-frequency signal in quadrature. Theoretically there is no effect on the forward signal, and the carrier of the backward signal can be eliminated, the energy distributed to other frequencies. We achieve a carrier isolation of 11 dB and an excess insertion loss of 2.3 dB. Such an isolator can be monolithically integrated with a laser without extra materials or magnetic fields.

  5. Waveguide optical isolator: a new design.

    PubMed

    Ando, K

    1991-03-20

    A new design of a thin film waveguide optical isolator is described. It is composed of a nonreciprocal mode converter by the Faraday effect, a reciprocal mode converter by the Cotton-Mouton effect, an integrated mirror, and TE-mode selectors. Its mode transfer matrices are derived. Numerical calculations show that wider tolerances of the film parameters and smaller dimensions are obtained compared with the ordinary tandem type waveguide isolators without the integrated mirror. This structure is free of the problem of the localized control of the directions of the magnetization, which has been required for the ordinary tandem type waveguide isolator.

  6. Feedback and Acousto Optic Isolation Effects on Laser Stability.

    DTIC Science & Technology

    1977-03-01

    This paper analyzes the effect of optical feedback on laser frequency stability and the acousto optic isolator concept, which was demonstrated...nonlinearity such as saturation in the laser medium. The analysis mathematically corroborates the initial acousto optic isolator concept and the...limited experimental data available. In the study of the acousto optic isolator, it was determined that an acceptable analytic expression for the

  7. Cascaded optical isolator configuration having high-isolation characteristics over a wide temperature and wavelength range.

    PubMed

    Shiraishi, K; Kawakami, S

    1987-07-01

    A new configuration of a cascaded optical isolator with high isolation over a wide range of temperature and wavelength is proposed. The configuration consists of two unit isolators, each of which is optimized for a different temperature and wavelength.

  8. Optically isolated signal coupler with linear response

    DOEpatents

    Kronberg, James W.

    1994-01-01

    An optocoupler for isolating electrical signals that translates an electrical input signal linearly to an electrical output signal. The optocoupler comprises a light emitter, a light receiver, and a light transmitting medium. The light emitter, preferably a blue, silicon carbide LED, is of the type that provides linear, electro-optical conversion of electrical signals within a narrow wavelength range. Correspondingly, the light receiver, which converts light signals to electrical signals and is preferably a cadmium sulfide photoconductor, is linearly responsive to light signals within substantially the same wavelength range as the blue LED.

  9. Optical Isolator For Use With Single-Mode Fiber

    NASA Technical Reports Server (NTRS)

    Lutes, George F.

    1988-01-01

    Assembly of commercially available components acts as single-mode fiber-optic isolator with lower forward-transmission loss and higher attenuation of reverse transmission than previously achieved in single unit. New design reduces cost and improves performance of optical gyroscopes, precise time- and frequency-signal-distribution systems, and other systems that include fiber optics and isolators.

  10. [Inferior vestibular neuritis: diagnosis using VEMP].

    PubMed

    Walther, L E; Repik, I

    2012-02-01

    Vestibular evoked myogenic potentials (VEMP) are a new method to establish the functional status of the otolith organs. The sacculocollic reflex of the cervical VEMP to air conduction (AC) reflects predominantly saccular function due to saccular afferents to the inferior vestibular nerve. We describe a case of inferior vestibular neuritis as a rare differential diagnosis of vestibular neuritis. Clinical signs were a normal caloric response, unilaterally absent AC cVEMPs and bilaterally preserved ocular VEMPs (AC oVEMPs).

  11. Fiber optically isolated and remotely stabilized data transmission system

    DOEpatents

    Nelson, M.A.

    1992-11-10

    A fiber optically isolated and remotely stabilized data transmission systems described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber. 3 figs.

  12. Fiber optically isolated and remotely stabilized data transmission system

    DOEpatents

    Nelson, Melvin A.

    1992-01-01

    A fiber optically isolated and remotely stabilized data transmission system s described wherein optical data may be transmitted over an optical data fiber from a remote source which includes a data transmitter and a power supply at the remote source. The transmitter may be remotely calibrated and stabilized via an optical control fiber, and the power source may be remotely cycled between duty and standby modes via an optical control fiber.

  13. Lens-free in-line optical isolators.

    PubMed

    Sato, T; Sun, J; Kasahara, R; Kawakami, S

    1999-10-01

    We constructed a lens-free in-line optical isolator by embedding an isolator chip in a thermally expanded core (TEC) fiber without complicated optical alignment. The chip consists of two pairs of rutile wedges and garnet plates. We fabricated the TEC fibers by heating a single-mode fiber with a 200-mum outer diameter; low loss and a spot diameter as large as 49 mum were successfully obtained. The fabricated isolator has excellent optical properties, an insertion loss of 0.45 dB, and an isolation of more than 50 dB at a 1.55-mum wavelength, which confirms the usefulness of the integration techniques.

  14. PT symmetry breaking and nonlinear optical isolation in coupled microcavities.

    PubMed

    Zhou, Xin; Chong, Y D

    2016-04-04

    We perform a theoretical study of the nonlinear dynamics of nonlinear optical isolator devices based on coupled microcavities with gain and loss. This reveals a correspondence between the boundary of asymptotic stability in the nonlinear regime, where gain saturation is present, and the PT -breaking transition in the underlying linear system. For zero detuning and weak input intensity, the onset of optical isolation can be rigorously derived, and corresponds precisely to the transition into the PT -broken phase of the linear system. When the couplings to the external ports are unequal, the isolation ratio exhibits an abrupt jump at the transition point, whose magnitude is given by the ratio of the couplings. This phenomenon could be exploited to realize an actively controlled nonlinear optical isolator, in which strong optical isolation can be turned on and off by tiny variations in the inter-resonator separation.

  15. 38 CFR 4.123 - Neuritis, cranial or peripheral.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Neuritis, cranial or....123 Neuritis, cranial or peripheral. Neuritis, cranial or peripheral, characterized by loss of... the scale provided for injury of the nerve involved, with a maximum equal to severe,...

  16. 38 CFR 4.123 - Neuritis, cranial or peripheral.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Neuritis, cranial or....123 Neuritis, cranial or peripheral. Neuritis, cranial or peripheral, characterized by loss of... the scale provided for injury of the nerve involved, with a maximum equal to severe,...

  17. 38 CFR 4.123 - Neuritis, cranial or peripheral.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Neuritis, cranial or....123 Neuritis, cranial or peripheral. Neuritis, cranial or peripheral, characterized by loss of... the scale provided for injury of the nerve involved, with a maximum equal to severe,...

  18. 38 CFR 4.123 - Neuritis, cranial or peripheral.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Neuritis, cranial or....123 Neuritis, cranial or peripheral. Neuritis, cranial or peripheral, characterized by loss of... the scale provided for injury of the nerve involved, with a maximum equal to severe,...

  19. 38 CFR 4.123 - Neuritis, cranial or peripheral.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Neuritis, cranial or....123 Neuritis, cranial or peripheral. Neuritis, cranial or peripheral, characterized by loss of... the scale provided for injury of the nerve involved, with a maximum equal to severe,...

  20. Optical isolator based on mode conversion in magnetic garnet films.

    PubMed

    Hemme, H; Dötsch, H; Menzler, H P

    1987-09-15

    Calculations are presented describing a novel optical isolator which works by complete TE(0)-TM(0) mode conversion in magnetic garnet films caused by stress-induced optical anisotropy (50%) and by Faraday rotation (50%). These conversions take place along two different, perpendicular light paths in the same crystal that are connected by an integrated mirror. Possible tolerances of the film parameters are given so that a 30-dB isolation is still guaranteed.

  1. Isolation of a single rice chromosome by optical micromanipulation

    NASA Astrophysics Data System (ADS)

    Wang, Haowei; Liu, Xiaohui; Li, Yinmei; Han, Bin; Lou, Liren; Wang, Kangjun

    2004-01-01

    A new method based on optical tweezers technology is reported for the isolation of a single chromosome. A rice cell suspended in liquid was first fragmented by laser pulses (optical scalpel). Then a single released chromosome from the cell was manipulated and pulled away from other cells and oddments by optical tweezers without any direct mechanical contact. Finally the isolated single chromosome was extracted individually into a glass capillary nearby. After molecular cloning of the isolated chromosome, we obtained some specific DNA segments from the single chromosome. All these segments can be used for rice genomic sequencing. Different methods of extracting a single chromosome are compared. The advantages of optical micromanipulation method are summarized.

  2. Faraday Rotation Optical Isolator for 10.6-microm Radiation.

    PubMed

    Jacobs, S D; Teegarden, K J; Ahrenkiel, R K

    1974-10-01

    Measurements that have been performed indicate that hot-pressed ferromagnetic CdCr(2)S(4) would be a useful Faraday optical isolator material for laser systems at 10.6 microm. A large-aperture, liquid-nitrogen-cooled isolator, requiring modest magnetic fields with material of optimum thickness, would provide isolation in excess of 30 dB with insertion loss due to optical absorption in the active element of less than 3 dB. Consideration of its figure of merit indicates that hot-pressed CdCr(2)S(4) could be used as an isolator at 1.06 microm, introducing less than 2 dB insertion loss due to optical absorption at that wavelength.

  3. Optical scattering from isolated metal nanoparticles and arrays.

    SciTech Connect

    Wurtz, G. A.; Im, J. S.; Gray, S. K.; Wiederrecht, G. P.; Chemistry

    2003-12-25

    Near-field scanning optical microscopy (NSOM) is used to explore the optical scattering from isolated metal nanoparticles (MNPs) and arrays of MNPs. The optical excitation source is an evanescent wave created through total internal reflection of a continuous wave laser beam at the sample-air interface. For optical excitation of isolated Ag and Au MNPs, experimental results show that the scattered light propagates into the far field at an angle of 19{sup o} from the substrate. Finite-difference time-domain (FDTD) calculations are used to study simpler but related metallic nanowire systems under evanescent wave excitation. The FDTD results are found to be similar to the experimental results, indicating the generality of the scattering phenomenon. NSOM characterization of plasmonic arrays that consist of closely spaced Ag MNPs are subsequently reported. Confined optical signals within the array are observed along with a reduction in the far-field scattered signal. Simultaneous collection of the atomic force microscopy signal and near-field signals also shows that the spatial distribution of the near-field is strongly modified in the arrays compared to isolated MNPs. FDTD studies on arrays of nanowires also show large differences from the isolated metal nanoparticle calculations, including a decrease in the forward scattered angle (with chain length) and diminished overall forward scattering.

  4. Silicon ring isolators with bonded nonreciprocal magneto-optic garnets.

    PubMed

    Tien, Ming-Chun; Mizumoto, Tetsuya; Pintus, Paolo; Kromer, Herbert; Bowers, John E

    2011-06-06

    A ring isolator is demonstrated for the first time by directly bonding a cerium-substituted yttrium iron garnet (Ce:YIG) onto a silicon ring resonator using oxygen plasma enhanced bonding. The silicon waveguide is 600 nm wide and 295 nm thick with 500-nm-thick Ce:YIG on the top to have reasonable nonreciprocal effect and low optical loss. With a radial magnetic field applied to the ring isolator, it exhibits 9-dB isolation at resonance in the 1550 nm wavelength regime.

  5. Dual stage passive vibration isolation for optical interferometer missions

    NASA Astrophysics Data System (ADS)

    Bronowicki, Allen J.; MacDonald, Rhonda; Gürsel, Yekta; Goullioud, Renaud; Neville, Timothy; Platus, David L.

    2003-02-01

    Future space-based optical instruments such as the Space Interferometer Mission have vibration-induced error allocations at the levels of a few nano-meters and milli-arc-seconds. A dual stage passive isolation approach has been proposed using isolation first at the vibration-inducing reaction wheels, and a second isolation layer between the bus portion of the space vehicle (the backpack) and the optical payload. The development of the backpack isolator is described, with unit transmissibility results for individual isolator struts. The dual stage isolation approach is demonstrated on a dynamically feature-rich, 7-meter structural testbed (STB3). A new passive suspension that mitigates ground vibrations above 0.4 Hz has been integrated into the testbed. A series of OPD performance predictions have been made using measured transfer functions. These indicate that the 5-nm dynamic OPD allocation is within reach using the dual isolator approach. Demonstrating these low response levels in a noisy air environment has proven to be difficult. We are sequentially executing a plan to mitigate acoustic transmission between backpack and flight structure, as well as developing techniques to mitigate effects of background acoustic noise.

  6. In-vacuum optical isolation changes by heating in a Faraday isolator.

    PubMed

    Acernese, Fausto; Alshourbagy, Mohamed; Amico, Paolo; Antonucci, Federica; Aoudia, S; Astone, P; Avino, Saverio; Ballardin, G; Baggio, L; Barone, Fabrizio; Barsotti, Lisa; Barsuglia, Matteo; Bauer, Th S; Bigotta, Stefano; Birindelli, Simona; Bizouard, Marie-Anne; Boccara, Albert-Claude; Bondu, François; Bosi, Leone; Braccini, Stefano; Bradaschia, Carlo; Brillet, Alain; Brisson, Violette; Buskulic, Damir; Cagnoli, G; Calloni, Enrico; Campagna, Enrico; Carbognani, Franco; Carbone, L; Cavalier, Fabien; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chatterji, S; Cleva, F; Coccia, E; Corda, C; Corsi, A; Cottone, F; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; De Rosa, R; Del Prete, M; Di Fiore, L; Di Lieto, A; Di Paolo Emilio, M; Di Virgilio, A; Evans, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Frasca, S; Frasconi, F; Gammaitoni, L; Garufi, F; Genin, E; Gennai, A; Giazotto, A; Giordano, L; Granata, V; Greverie, C; Grosjean, D; Guidi, G; Hamdani, S; Hebri, S; Heitmann, H; Hello, P; Huet, D; La Penna, P; Laval, M; Leroy, N; Letendre, N; Lopez, B; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J-M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Menzinger, F; Milano, L; Minenkov, Y; Moins, C; Morgado, N; Mosca, S; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palomba, C; Paoletti, F; Pardi, S; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Piergiovanni, F; Pinard, L; Poggiani, R; Punturo, M; Puppo, P; Rabaste, O; Rapagnani, P; Regimbau, T; Remillieux, A; Ricci, F; Ricciardi, I; Rocchi, A; Rolland, L; Romano, R; Ruggi, P; Russo, G; Sentenac, D; Solimeno, S; Swinkels, B L; Tarallo, M; Terenzi, R; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Vajente, G; van den Brand, J F J; van der Putten, S; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Yvert, M

    2008-11-01

    We describe a model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal. The changes are particularly significant in the crystal thermal lensing (refraction index and thermal expansion) and in its Verdet constant and can be ascribed to the less efficient convection cooling of the magneto-optic crystal of the Faraday isolator. An isolation decrease by a factor of 10 is experimentally observed in a Faraday isolator that is used in a gravitational wave experiment (Virgo) with a 10 W input laser when going from air to vacuum. A finite element model simulation reproduces with a great accuracy the experimental data measured on Virgo and on a test bench. A first set of measurements of the thermal lensing has been used to characterize the losses of the crystal, which depend on the sample. The isolation factor measured on Virgo confirms the simulation model and the absorption losses of 0.0016 +/- 0.0002/cm for the TGG magneto-optic crystal used in the Faraday isolator.

  7. Compact optical isolator for fibers using birefringent wedges.

    PubMed

    Shirasaki, M; Asama, K

    1982-12-01

    A new type of optical isolator for fibers is proposed in this paper. A birefringent wedge used to separate and combine the polarized light is developed, giving the isolator low forward loss and high isolation. The antire-flection process at the fiber endface reduces the forward loss and reflected return. A forward loss of 0.8 dB, a backward loss of 35 dB, and a reflected return of -32 dB were obtained. These characteristics were measured from fiber to fiber using multimode fibers with 50-/microm core diam at a wavelength of 1.3 microm. Details of the design, fabrication, and characteristics of this isolator are presented.

  8. A high-performance single-mode fiber-optic isolator assembly

    NASA Technical Reports Server (NTRS)

    Lutes, G.

    1987-01-01

    A high-isolation single-mode fiber optic isolator assembly was designed and fabricated. The measured forward loss is 2.6 dB and the reverse loss (isolation) is greater than 70 dB. This is a 30-dB higher isolation than the isolation of the best fiber optic isolator previously reported. This isolator provides isolation between the semiconductor laser diode and the optical fiber in a precise reference frequency transmission system. The isolation of the laser greatly reduces the system's sensitivity to microphonics.

  9. Enhancing optical isolator performance in nonreciprocal waveguide arrays.

    PubMed

    Levy, Miguel; Carroll, Turhan K; El-Ganainy, Ramy

    2015-01-01

    We investigate the operation of optical isolators based on magneto-optics waveguide arrays beyond the coupled mode analysis. Semi-vectorial beam propagation simulations demonstrate that evanescent tail coupling and the effects of radiation are responsible for degrading the device's performance. Our analysis suggests that these effects can be mitigated when the array size is scaled up. In addition, we propose the use of radiation blockers in order to offset some of these effects, and we show that they provide a dramatic improvement in performance. Finally, we also study the robustness of the system with respect to fabrication tolerances using the coupled mode theory. We show that small, random variations in the system's parameters tend to average out as the number of optical guiding channels increases.

  10. Optical isolation in topological-edge-state photonic arrays.

    PubMed

    El-Ganainy, Ramy; Levy, Miguel

    2015-11-15

    We introduce a new type of optical isolator based on breaking time reversal symmetry in dissipative finite Su-Schrieffer-Heeger (SSH) waveguide arrays that support topological edge states at one end of the structure. In the forward propagation direction, light is launched into the edge waveguide to excite the localized topological midgap state. As a result, most of the input optical power is transmitted to the output port. On the other hand, backward reflected light encounters a propagation constant mismatch in that same channel which shifts the otherwise midgap state into one of the bands and hence becomes delocalized over the whole array. We show that under these conditions, a judicious spatial distribution of the optical dissipation across the structure can produce an isolation ratio of -50 dB. The required nonreciprocal phase shift is introduced by depositing a magnetic garnet film only on the edge waveguide and, thus, the required magnetic field can be generated by an integrated micromagnet. Similar concepts can also be applied to SSH arrays made from optical resonators.

  11. Optic neuropathy in a child with primary Sjögren's syndrome.

    PubMed

    Rojas-Rodriguez, J; Garcia-Carrasco, M; Ramirez, E S; Romero-Rodriguez, F; Ramos-Casals, M; Rojas-Serrano, J; Terrazas-Ramirez, A

    1998-05-01

    An eight-year-old girl developed optic neuritis followed by primary Sjögren's syndrome confirmed by a lip biopsy. Glucocorticoid therapy combined during six months with monthly intravenous pulse cyclophosphamide ensured resolution of the sicca syndrome but failed to improve the visual impairment. This is the second pediatric case of optic neuritis associated with primary Sjögren's syndrome, and the first pediatric case in which optic neuritis was the only neurologic manifestation.

  12. High-isolation optical isolator using a BiCalnVIG single crystal.

    PubMed

    Ma, X; Tao, S

    1992-07-20

    To the best of our knowledge this is the first time a new optical isolator has been developed that uses BiCaInVIG, a non-rare-earth iron garnet. The device has high isolation > 40 dB with an insertion loss of 1.0 dB at 1.3-microm wavelength and > 43 dB with 1.1 dB at 1.52-microm wavelength, including Fresnel reflection losses of ~0.8 dB for two polarizers. In addition, the device is inexpensive. In order to adjust maximum isolation when the isolator is assembled, a theoretical basis is presented, and the calculated values are in good agreement with the experimental results.

  13. All-optical isolator under arbitrary linearly polarized fundamental wave in an optical superlattice.

    PubMed

    Yuan, Liang; Shi, Jianhong; Chen, Xianfeng

    2011-12-01

    We theoretically investigate an all-optical isolator under arbitrary linearly polarized fundamental wave (FW) input in an optical superlattice (OSL). The scheme is based on simultaneously phase matching the first-order Type I (oo-e) quasi-phase-matching (QPM) second-harmonic generation (SHG) process and higher-order Type 0 (ee-e) QPM SHG process in an OSL with a defect inserted in an asymmetrical position. Simulation results show that the contrast ratio of the all-optical isolator can maintain close to 1 under arbitrary linearly polarized FW. Thus, an all-optical isolator based on an OSL that is not sensitive to the direction of linear polarization can be realized. We also show that, with the defect in a strong asymmetry position, the length of the defect can be designed flexibly to maintain a high contrast ratio. Additionally, if the length of the OSL is longer, the nonreciprocal response can be realized for low optical intensities.

  14. Visual dependency and dizziness after vestibular neuritis.

    PubMed

    Cousins, Sian; Cutfield, Nicholas J; Kaski, Diego; Palla, Antonella; Seemungal, Barry M; Golding, John F; Staab, Jeffrey P; Bronstein, Adolfo M

    2014-01-01

    Symptomatic recovery after acute vestibular neuritis (VN) is variable, with around 50% of patients reporting long term vestibular symptoms; hence, it is essential to identify factors related to poor clinical outcome. Here we investigated whether excessive reliance on visual input for spatial orientation (visual dependence) was associated with long term vestibular symptoms following acute VN. Twenty-eight patients with VN and 25 normal control subjects were included. Patients were enrolled at least 6 months after acute illness. Recovery status was not a criterion for study entry, allowing recruitment of patients with a full range of persistent symptoms. We measured visual dependence with a laptop-based Rod-and-Disk Test and severity of symptoms with the Dizziness Handicap Inventory (DHI). The third of patients showing the worst clinical outcomes (mean DHI score 36-80) had significantly greater visual dependence than normal subjects (6.35° error vs. 3.39° respectively, p = 0.03). Asymptomatic patients and those with minor residual symptoms did not differ from controls. Visual dependence was associated with high levels of persistent vestibular symptoms after acute VN. Over-reliance on visual information for spatial orientation is one characteristic of poorly recovered vestibular neuritis patients. The finding may be clinically useful given that visual dependence may be modified through rehabilitation desensitization techniques.

  15. Visual Dependency and Dizziness after Vestibular Neuritis

    PubMed Central

    Cousins, Sian; Cutfield, Nicholas J.; Kaski, Diego; Palla, Antonella; Seemungal, Barry M.; Golding, John F.; Staab, Jeffrey P.; Bronstein, Adolfo M.

    2014-01-01

    Symptomatic recovery after acute vestibular neuritis (VN) is variable, with around 50% of patients reporting long term vestibular symptoms; hence, it is essential to identify factors related to poor clinical outcome. Here we investigated whether excessive reliance on visual input for spatial orientation (visual dependence) was associated with long term vestibular symptoms following acute VN. Twenty-eight patients with VN and 25 normal control subjects were included. Patients were enrolled at least 6 months after acute illness. Recovery status was not a criterion for study entry, allowing recruitment of patients with a full range of persistent symptoms. We measured visual dependence with a laptop-based Rod-and-Disk Test and severity of symptoms with the Dizziness Handicap Inventory (DHI). The third of patients showing the worst clinical outcomes (mean DHI score 36–80) had significantly greater visual dependence than normal subjects (6.35° error vs. 3.39° respectively, p = 0.03). Asymptomatic patients and those with minor residual symptoms did not differ from controls. Visual dependence was associated with high levels of persistent vestibular symptoms after acute VN. Over-reliance on visual information for spatial orientation is one characteristic of poorly recovered vestibular neuritis patients. The finding may be clinically useful given that visual dependence may be modified through rehabilitation desensitization techniques. PMID:25233234

  16. GaInAsP/InP MZI waveguide optical isolator integrated with spot size converter.

    PubMed

    Sobu, Yohei; Shoji, Yuya; Sakurai, Kazumasa; Mizumoto, Tetsuya

    2013-07-01

    We fabricated a waveguide optical isolator with a GaInAsP guiding layer integrated with spot size converters (SSCs) for efficient coupling to optical fibers. The isolator is constructed with a Mach-Zehnder interferometer (MZI), which is composed of multi-mode interference (MMI) couplers, as well as nonreciprocal and reciprocal phase shifters. The nonreciprocal phase shifter is constructed with a magneto-optical cladding layer directly bonded to a semiconductor guiding layer. The performance of the GaInAsP waveguide optical isolator was demonstrated with a maximum optical isolation of 28.3 dB at a wavelength of 1558 nm for the TM mode.

  17. [Applications of optical coherence tomography (OCT) in neuro-ophthalmology].

    PubMed

    Kernstock, C; Friebe, K; Tonagel, F

    2013-11-01

    Optical coherence tomography (OCT) has revolutionised ophthalmology. Due to modern instruments with extremely high resolution there are more and more applications also in neuro-ophthalmological disorders. This review gives an overview on typical changes in OCT for the following diseases: autosomal dominant optic atrophy, Leber hereditary optic neuropathy, toxic, traumatic and compressive optic neuropathy, optic nerve drusen, anterior ischaemic optic neuropathy, optic disc pit, papilledema, optic neuritis (isolated or associated with multiple sclerosis or neuromyelitis optica), neurodegenerative diseases and hereditary retinal diseases. A diagnosis exclusively based on an OCT examination is not always possible, but in several diseases there are pathognomonic changes that directly lead to the correct diagnosis. Particularly with the often complex settings in neuro-ophtalmology the OCT should be seen as a supplementary modality and not as a replacement for other techniques.

  18. Ultracompact nonreciprocal optical isolator based on guided resonance in a magneto-optical photonic crystal slab.

    PubMed

    Fang, Kejie; Yu, Zongfu; Liu, Victor; Fan, Shanhui

    2011-11-01

    We design an ultracompact optical isolator with normal incident geometry that operates with a bandwidth that is substantial for a device of this size. For operation in a telecommunication wavelength of 1.55 μm, the thickness of the device is less than 1 μm and the device supports an operating bandwidth of 400 GHz over which the minimum contrast ratio exceeds 25 dB. Our design utilizes guided resonance in a photonic crystal slab to enhance magneto-optical effects, and exploits interference effects among multiple resonances to create desired transmission spectral line shapes.

  19. Optical payload isolation using the Miniature Vibration Isolation System (MVIS-II)

    NASA Astrophysics Data System (ADS)

    McMickell, M. B.; Kreider, Thom; Hansen, Eric; Davis, Torey; Gonzalez, Mario

    2007-04-01

    Precision satellite payloads commonly require isolation from bus disturbance sources, such as reaction wheels, thrusters, stepper motors, cryo-coolers, solar array drives, thermal popping, and other moving devices. Since nearly every satellite essentially has a unique construction, custom isolation systems are usually designed to attenuate a wide bandwidth of disturbance frequencies. The disadvantage of these custom solutions is that they are not easily reusable or transferable and are generally not robust to changes in payload geometry and mass properties during the development. The MVIS-II isolation system is designed to provide vibration disturbance attenuation over a wide bandwidth, as well as being able to adapt to changes in payload mass properties and geometry, through active control of a smart material. MVIS-II is a collaborative effort between the Air Force Research Laboratory (AFRL) Space Vehicle Directorate and Honeywell Defense and Space to validate miniature hybrid (passive/active) vibration isolation of sensitive optical payloads. The original flight experiment was intended to isolate a non-critical representative payload mass for demonstration purposes; however, the MVIS-II has been adapted to support the primary optical payload onboard the Tactical Satellite 2 (TacSat-2). Throughout the program MVIS-II has been able to adapt to changes in the payload geometry and mass properties with modification limited to support structures only. The MVIS-II system consists of a hexapod of hybrid struts, where each strut includes a patented passive 3-parameter DStrut n series with a novel hydraulically amplified piezoelectric actuator with integral load cell. Additionally, Honeywell's Flexible I/O controller electronics and software are used for command and control of the hardware. The passive D-Strut element provides a 40 dB/decade passive roll-off to attenuate mid-to-high frequency disturbances, while the active piezoelectric actuator is used for enhanced low

  20. Inferior vestibular neuritis in a fighter pilot: a case report.

    PubMed

    Xie, Su Jiang; Jia, Hong Bo; Xu, Po; Zheng, Ying Juan

    2013-06-01

    Spatial disorientation in airplane pilots is a leading factor in many fatal flying accidents. Spatial orientation is the product of integrative inputs from the proprioceptive, vestibular, and visual systems. One condition that can lead to sudden pilot incapacitation in flight is vestibular neuritis. Vestibular neuritis is commonly diagnosed by a finding of unilateral vestibular failure, such as a loss of caloric response. However, because caloric response testing reflects the function of only the superior part of the vestibular nerve, it cannot detect cases of neuritis in only the inferior part of the nerve. We describe the case of a Chinese naval command fighter pilot who exhibited symptoms suggestive of vestibular neuritis but whose caloric response test results were normal. Further testing showed a unilateral loss of vestibular evoked myogenic potentials (VEMPs). We believe that this pilot had pure inferior nerve vestibular neuritis. VEMP testing plays a major role in the diagnosis of inferior nerve vestibular neuritis in pilots. We also discuss this issue in terms of aeromedical concerns.

  1. Normal Caloric Responses during Acute Phase of Vestibular Neuritis

    PubMed Central

    Lee, Sun-Uk; Park, Seong-Ho; Kim, Hyo-Jung; Koo, Ja-Won

    2016-01-01

    Background and Purpose We report a novel finding of caloric conversion from normal responses into unilateral paresis during the acute phase of vestibular neuritis (VN). Methods We recruited 893 patients with a diagnosis of VN at Dizziness Clinic of Seoul National University Bundang Hospital from 2003 to 2014 after excluding 28 patients with isolated inferior divisional VN (n=14) and those without follow-up tests despite normal caloric responses initially (n=14). We retrospectively analyzed the neurotological findings in four (0.5%) of the patients who showed a conversion from initially normal caloric responses into unilateral paresis during the acute phase. Results In those four patients, the initial caloric tests were performed within 2 days of symptom onset, and conversion into unilateral caloric paresis was documented 1–4 days later. The clinical and laboratory findings during the initial evaluation were consistent with VN in all four patients except for normal findings in bedside head impulse tests in one of them. Conclusions Normal findings in caloric tests should be interpreted with caution during the acute phase of suspected VN. Follow-up evaluation should be considered when the findings of the initial caloric test are normal, but VN remains the most plausible diagnosis. PMID:26932259

  2. Interferometric optical isolator employing a nonreciprocal phase shift operated in a unidirectional magnetic field.

    PubMed

    Yokoi, Hideki; Shoji, Yuya; Shin, Etsu; Mizumoto, Tetsuya

    2004-08-20

    An interferometric optical isolator that employs a nonreciprocal phase shift was studied. The optical isolator consisted of an interferometer with distinct layer structures. A traveling light wave underwent distinct nonreciprocal phase shifts such that the optical isolator could be operated in a unidirectional magnetic field. The optical isolator, in which the waveguide had a HfO2 cladding layer in one of the arms, was designed at a wavelength of 1.55 microm. The propagation distance of the nonreciprocal phase shifter required for the isolator's operation was less than 1.5 mm. The device's total length was less than 2 mm. An optical isolator with distinct layer structures was fabricated and evaluated. An isolation ratio of approximately 9.9 dB was obtained in the unidirectional magnetic field.

  3. Wideband operation of Mach-Zehnder interferomertic magneto-optical isolator using phase adjustment.

    PubMed

    Shoji, Yuya; Mizumoto, Tetsuya

    2007-10-01

    A wideband operation of a magneto-optical isolator is demonstrated. The isolator is based on a Mach-Zehnder interferometer employing nonreciprocal phase shift. The wideband operation is achieved by adjusting a reciprocal phase difference in the interferometer. We designed and fabricated a wideband isolator with a magneto-optic garnet waveguide. The isolation ratio of 15-25dB was obtained in a wavelength range from 1530nm to 1640nm.

  4. Adjustable magneto-optical isolators with flat-top responses.

    PubMed

    Zamani, Mehdi; Ghanaatshoar, Majid

    2012-10-22

    In order to construct flat-top magneto-optical isolators (MOIs), we have performed a theoretical study on the case of transmission-type one-dimensional magnetophotonic crystals (MPCs). We have introduced high performance MPC structures with flat-top responses and with the capability of adjusting to perfect MOIs. The adjustment is carried out by tuning the applied magnetic field. All introduced MOIs are sufficiently thin with acceptable transmission bandwidth. In the best case, we have achieved a 19.42 μm-thick perfect MOI with the flat-top width of 7.2 nm. For practical purposes, we have also considered the influence of the error in thickness of individual layers on the operational parameters of the MOIs and investigated the possibility of compensating the deviations by the magnetic adjustment.

  5. Optical power of the isolated human crystalline lens

    PubMed Central

    Borja, David; Manns, Fabrice; Ho, Arthur; Ziebarth, Noel; Rosen, Alexandre M.; Jain, Rakhi; Amelinckx, Adriana; Arrieta, Esdras; Augusteyn, Robert C.; Parel, Jean-Marie

    2009-01-01

    Purpose To characterize the age-dependence of isolated human crystalline lens power and quantify the contributions of the lens surfaces and refractive index gradient. Methods Experiments were performed on a total of 100 eyes from 73 donors (average post-mortem: 2.8±1.6 days) with an age range of 6 to 94 years. Lens power was measured with a modified commercial lensmeter or with an optical system based on the Scheiner principle. The radius of curvature and asphericity of the isolated lens surfaces were measured by shadowphotography. For each lens the contributions of the surfaces and the refractive index gradient to the measured lens power were calculated using an optical ray tracing software. The age dependency of these refractive powers was assessed. Results The total refractive power and surface refractive power both showed a biphasic age dependency. The total power decreased at a rate of −0.41D/year between age 6 and 58.1, and increased at a rate of 0.33D/year between age 58.1 and 82. The surface contribution decreased at a rate of −0.13D/year between age 6 and 55.2, and increased at a rate of 0.04D/year between age 55.2 and 94. The relative contribution of the surfaces increased by 0.17%/year. The equivalent refractive index also showed a biphasic age dependency with a decrease at a rate of −3.9×10−4/year from age 6 to 60.4 followed by a plateau. Conclusions The lens power decreases with age due mainly to a decrease in the contribution of the gradient. The use of a constant equivalent refractive index value to calculate lens power using the lens maker formula will underestimate the power of young lenses and overestimate the power of older lenses. PMID:18316704

  6. Edge Detection to Isolate Motion in Adaptive Optics Systems

    SciTech Connect

    Chan, C W

    2003-07-11

    Adaptive optics uses signal processing techniques and deformable mirrors to minimize image degradation caused by phase aberrations. In the case of telescope imaging, the atmosphere causes phase aberrations. In the case of satellite imaging, errors due to the ultra-light-weight characteristics of the primary mirror cause phase aberrations. Scene-based Shack-Hartmann Wave Front Sensing takes the correlation between successive wavelets to determine these phase aberrations. A large problem with the scene-based approach is that motion, such as a moving car, can cause the correlation of two lenslets to peak, not where the scenes align, but where the moving object in each frame aligns. As such, the continued use of scene-based Wave Front Sensing necessitates successful isolation of moving objects from a stationary background scene. With the knowledge of which pixels are immobile, one should avoid the problem of locking onto a moving object when taking the correlation of two successive frames in time. Two main requirements of isolation are consistency and efficiency. In this document I will discuss the different edge detection algorithms explored for moving object isolation and how I came to the conclusion that, for our purposes of scene-based Shack-Hartmann WFS, edge detection is too inconsistent to be of any use. Because the Shack-Hartmann lenslets limits us to low resolutions, edge detection that works on higher resolution images will not work on our images. The results of each algorithm will show that with so few pixels per subaperature, edge detection is a poor method of identifying moving objects.

  7. Forced-exercise attenuates experimental autoimmune neuritis.

    PubMed

    Calik, Michael W; Shankarappa, Sahadev A; Stubbs, Evan B

    2012-07-01

    Physical inactivity in combination with a sedentary lifestyle is strongly associated with an increased risk of development of inflammatory-mediated diseases, including autoimmune disorders. Recent studies suggest that anti-inflammatory effects of physical exercise may be of therapeutic value in some affected individuals. In this study, we determined the effects of forced-exercise (treadmill running) on the development and progression of experimental autoimmune neuritis (EAN), an established animal model of Guillain-Barré syndrome. Adult male Lewis rats were subjected to sedentary (control) or forced-exercise (1.2 km per day, 5 days a week) for three weeks prior to induction of EAN. P2 (53-78)-immunized sedentary control rats developed a monophasic course of EAN beginning on post-injection day 12.33 ± 0.59 (n = 18) and reaching peak severity on day 15.83 ± 0.35 (n = 18). At near peak of disease, ankle- and sciatic notch-evoked compound muscle action potential (CMAP) amplitudes in sedentary control rats were reduced (~50%) while motor nerve conduction velocity (MNCV) was slowed (~30%) compared with pre-induction evoked responses. In marked contrast, rats undergoing forced-exercise exhibited a significantly less severe clinical course of EAN beginning on post-injection day 12.63 ± 0.53 (n = 16) and reaching peaking severity on day 14.69 ± 0.73 (n = 16). At near peak of disease, ankle- and sciatic-notch-evoked CMAP amplitudes in forced-exercised rats were preserved while EAN-associated slowing of MNCV was modestly attenuated by exercise. Three weeks of forced-exercise reduced by 46% total plasma corticosterone content while elevating the levels of corticosteroid binding globulin. We conclude from this study that forced-exercise administered prior to and during development of EAN affords a novel measure of protection against autoimmune-associated deficits in peripheral nerve evoked responses independent of steroid-induced immune suppression.

  8. Hybrid graphene/silicon integrated optical isolators with photonic spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Ma, Jingwen; Xi, Xiang; Yu, Zejie; Sun, Xiankai

    2016-04-01

    Optical isolators are an important building block in photonic computation and communication. In traditional optics, isolators are realized with magneto-optical garnets. However, it remains challenging to incorporate such materials on an integrated platform because of the difficulty in material growth and bulky device footprint. Here, we propose an ultracompact integrated isolator by exploiting graphene's magneto-optical property on a silicon-on-insulator platform. The photonic nonreciprocity is achieved because the cyclotrons in graphene experiencing different optical spins exhibit different responses to counterpropagating light. Taking advantage of cavity resonance effects, we have numerically optimized a device design, which shows excellent isolation performance with the extinction ratio over 45 dB and the insertion loss around 12 dB at a wavelength near 1.55 μm. Featuring graphene's CMOS compatibility and substantially reduced device footprint, our proposal sheds light on monolithic integration of nonreciprocal photonic devices.

  9. A Sociological Study of the Optically Emitting Isolated Neutron Stars

    NASA Astrophysics Data System (ADS)

    Caraveo, Patrizia A.

    Although less than 1% of all radio pulsars are detected at optical wavelengths, their optical emission can yield a wealth of information that is either very difficult or plainly impossible to obtain at other wavelengths.

  10. On-chip optical isolation via unidirectional Bloch oscillations in a waveguide array.

    PubMed

    Kumar, Pradeep; Levy, Miguel

    2012-09-15

    We propose to use the unidirectionality of the optical Bloch oscillation phenomenon achievable in a magneto-optic asymmetric waveguide array to achieve optical isolation. At the 1.55 μm telecommunication wavelength, our isolator design exhibits an isolation ratio of 36 dB between forward- and backward-propagating waves. The proposed design consists of a waveguide array made in a silicon-on-insulator substrate with a magnetic garnet cover layer. A key role is played by the transverse-magnetic mode nonreciprocal phase shift effect.

  11. Cascaded transformerless DC-DC voltage amplifier with optically isolated switching devices

    NASA Technical Reports Server (NTRS)

    Sridharan, Govind (Inventor)

    1993-01-01

    A very high voltage amplifier is provided in which plural cascaded banks of capacitors are switched by optically isolated control switches so as to be charged in parallel from the preceding stage or capacitor bank and to discharge in series to the succeeding stage or capacitor bank in alternating control cycles. The optically isolated control switches are controlled by a logic controller whose power supply is virtually immune to interference from the very high voltage output of the amplifier by the optical isolation provided by the switches, so that a very high voltage amplification ratio may be attained using many capacitor banks in cascade.

  12. Is Vestibular Neuritis an Immune Related Vestibular Neuropathy Inducing Vertigo?

    PubMed Central

    Greco, A.; Macri, G. F.; Gallo, A.; Fusconi, M.; De Virgilio, A.; Pagliuca, G.; Marinelli, C.; de Vincentiis, M.

    2014-01-01

    Objectives. To review the current knowledge of the aetiology of vestibular neuritis including viral infections, vascular occlusion, and immunomediated mechanisms and to discuss the pathogenesis with relevance to pharmacotherapy. Systematic Review Methodology. Relevant publications on the aetiology and treatment of vestibular neuritis from 1909 to 2013 were analysed. Results and Conclusions. Vestibular neuritis is the second most common cause of peripheral vestibular vertigo and is due to a sudden unilateral loss of vestibular function. Vestibular neuronitis is a disorder thought to represent the vestibular-nerve equivalent of sudden sensorineural hearing loss. Histopathological studies of patients who died from unrelated clinical problems have demonstrated degeneration of the superior vestibular nerve. The characteristic signs and symptoms include sudden and prolonged vertigo, the absence of auditory symptoms, and the absence of other neurological symptoms. The aetiology and pathogenesis of the condition remain unknown. Proposed theories of causation include viral infections, vascular occlusion, and immunomediated mechanisms. The management of vestibular neuritis involves symptomatic treatment with antivertiginous drugs, causal treatment with corticosteroids, and physical therapy. Antiviral agents did not improve the outcomes. PMID:24741601

  13. Vestibular neuritis: is there any evidence of an asymmetric distribution?

    PubMed

    Reiß, Michael; Reiß, Gilfe

    2012-04-01

    Statistics in the literature showed that neuro-otological diseases (i.e. sudden hearing loss or tinnitus) occur predominantly in the left ear. In a seven-study meta-analysis of patients suffering from vestibular neuritis, Reiß found no clear dominance of one side (50.8% on the right side, 48.4% on the left side and 0.8% on both sides). The purpose of this study is to investigate the laterality of vestibular neuritis in a distinct population of patients. Lateralization of vestibular neuritis was studied in 160 patients treated at Elblandklinikum Radebeul from January 2004 to December 2009. There was a statistically non-significant dominance of the right side in the total sample, specifically in female patients (57% right vs. 40% left), but not in male patients. The study confirms the results of the meta-analysis: that there is no relevant side dominance in patients suffering from vestibular neuritis. In addition to the caloric test, the head impulse test was performed in 157 patients. In 92% of these patients, the disturbance of vestibular function could be confirmed with the head impulse test. This test is altogether a clinically useful instrument especially for follow-up, but also for diagnosis.

  14. MZI optical isolator with Si-wire waveguides by surface-activated direct bonding.

    PubMed

    Shoji, Yuya; Ito, Masatoshi; Shirato, Yuya; Mizumoto, Tetsuya

    2012-07-30

    We fabricate a Mach-Zehnder interferometer-based optical isolator using a silicon-wire waveguide with magneto-optic garnet cladding using direct bonding techniques. Using Si-wire waveguides, the size of the device is greatly reduced from that of our previous device. We investigate surface-activated direct bonding with nitrogen plasma treatment, which shows better bonding results than oxygen plasma treatment. A large magneto-optic phase shift of 0.8π and an optical isolation of 18 dB are obtained at a wavelength of 1322 nm.

  15. Demonstration of an optical isolator by use of a nonreciprocal phase shift.

    PubMed

    Yokoi, H; Mizumoto, T; Takano, T; Shinjo, N

    1999-12-20

    The experimental study of an optical isolator by use of a nonreciprocal phase shift is demonstrated. The isolator has an optical interferometer composed of tapered couplers, nonreciprocal phase shifters, and a reciprocal phase shifter. The isolator, designed for a 1.55-microm wavelength, was fabricated to investigate the characteristics of each component. The branching and coupling characteristics of the tapered coupler were measured. The nonreciprocal and reciprocal phase shifts were also evaluated. By applying an external magnetic field to the interferometer, we confirmed the nonreciprocal phase shift in the interferometric isolator.

  16. Travelling-wave Mach-Zehnder modulators functioning as optical isolators.

    PubMed

    Dong, Po

    2015-04-20

    On-chip optical isolators not requiring the use of magneto-optical materials has become a long-standing challenge in integrated optics. Here, we demonstrate that a traditional travelling-wave modulator can effectively function as an optical isolator, when driven under a prescribed modulation condition. By using an off-shelve lithium niobate modulator, we achieve more than 12.5 dB isolation over an 11.3-THz bandwidth at telecommunication wavelengths with a fiber-to-fiber insertion loss of 5.5 dB, by employing only a single radio-frequency drive signal. We also verify that the proposed active isolator can be functional in a laser system to effectively prevent instability due to strong back reflections. Since travelling-wave modulators are common devices in III-V and silicon photonics, our simple but efficient architecture may provide a practical solution to non-reciprocal light routing in photonic integrated circuits.

  17. Isolated optic nerve oedema as unusual presentation of electric injury.

    PubMed

    Izzy, Saef; Deeb, Wissam; Peters, George B; Mitchell, Ann

    2014-10-15

    A 45-year-old man with no significant medical history presented following an electric current injury (380 V). He developed multiple systemic injuries including third degree burns and after 1 week of hospitalisation he reported unilateral visual changes. Examination suggested the presence of optic nerve oedema without evidence of haemorrhage, exudate or vessel abnormality. This was considered to be related to the electric shock. A trial of corticosteroids was considered. He was followed up to 5 months in clinic and was noted to have developed unilateral optic atrophy and no other systemic manifestations. Initial and 5 months follow-up optic nerve colour photograph and optical coherence topography were documented. The present case highlights the fact that electric current injury can present with only a unilateral ischaemic optic neuropathy, the need for early diagnosis for timely treatment and the controversial role of corticosteroids.

  18. Ce:YIG/Silicon-on-Insulator waveguide optical isolator realized by adhesive bonding.

    PubMed

    Ghosh, S; Keyvavinia, S; Van Roy, W; Mizumoto, T; Roelkens, G; Baets, R

    2012-01-16

    A waveguide optical isolator realized by adhesive bonding of a garnet die, containing a Ce:YIG magneto-optic layer, on a silicon-on-insulator waveguide circuit is demonstrated. The die was bonded on top of an asymmetric Mach-Zehnder interferometer using a 100nm thick DVS-BCB adhesive bonding layer. A static magnetic field applied perpendicular to the light propagation direction results in a non-reciprocal phase shift for the fundamental quasi-TM mode in the hybrid waveguide geometry. A maximum optical isolation of 25 dB is obtained.

  19. Vector-component isolation of an arbitrary modulating electric field in zincblende electro-optic probes

    NASA Astrophysics Data System (ADS)

    Reano, Ronald M.; Whitaker, John F.; Katehi, Linda P. B.

    2005-08-01

    Analysis of the field-induced linear birefringence in zincblende crystals shows that one can obtain complete isolation of a single vector component of an arbitrary modulating electric field. For an optical probe beam path aligned parallel to the [110] direction and an optical probe beam polarization aligned parallel to the [110] direction, the field-induced birefringence occurs only for the component of the modulating electric field aligned parallel to the [110] direction. Measurements using a modulating electric field with known polarization and electro-optic probes machined from (110) gallium arsenide wafers demonstrate an alignment-limited isolation between orthogonal modulating electric field components of 17 dB.

  20. Tunable broadband isolator based on electro-optically induced linear gratings in a nonlinear photonic crystal.

    PubMed

    Yu, Zi-Yan; Xu, Fei; Lin, Xiao-Wen; Song, Xiao-Shi; Qian, Xiao-Shi; Wang, Qin; Lu, Yan-Qing

    2010-10-15

    We theoretically propose a broadband optical isolator based on second-harmonic generation in a one-dimensional quadratic nonlinear photonic crystal (NPC) with an embedded defect. An external electric field along the z axis is applied to modulate the NPC refractive index periodically. Complete optical isolation always could be reached with the help of an external field. Influences of the defect position and thickness are discussed. The spectral and power tolerances of the isolator also have been investigated and show high contrast within a wide wavelength range at different power levels.

  1. Wartenberg's migrant sensory neuritis: a prospective follow-up study.

    PubMed

    Stork, Abraham C J; van der Meulen, Marjon F G; van der Pol, W-Ludo; Vrancken, Alexander F J E; Franssen, Hessel; Notermans, Nicolette C

    2010-08-01

    Migrant sensory neuropathy (Wartenberg's migrant sensory neuritis) is characterized by sudden numbness in the distribution of one or multiple cutaneous nerves. To study disease course and outcome, we prospectively followed 12 patients who presented to our tertiary referral neuromuscular outpatient clinic between January 2003 and January 2004. Medical history, neurological, laboratory and electrophysiological examinations were obtained from all patients. All patients were reviewed a second time in 2007, and five had a follow-up electrophysiological examination. At the first visit, 50% described an episode of stretching preceding the sensory complaints. All but three described pain in the affected area before or concomitant with sensory loss. At clinical examination a median of six skin areas were affected, and in 75% this could be confirmed by nerve conduction studies in at least one nerve. Forty-two percent had involvement of the trigeminal nerve. After a mean disease duration of 7.5 years, three patients reported a complete disappearance of sensory complaints and five that the pain had disappeared, but numbness remained. Three patients still had both painful and numb sensory deficits. One patient developed a distal symmetric sensory polyneuropathy. In conclusion, Wartenberg's sensory neuritis is a distinct, exclusively sensory, neuropathy, marked by pain preceding numbness in affected nerves. An episode of stretching preceding pain is not necessary for the diagnosis. Wartenberg's sensory neuritis often retains its spotty, exclusively sensory characteristics after long term follow-up.

  2. A case of secondary syphilis presenting as optic neuritis.

    PubMed

    Bandettini di Poggio, Monica; Primavera, Alberto; Capello, Elisabetta; Bandini, Fabio; Mazzarello, Giovanni; Viscoli, Claudio; Schenone, Angelo

    2010-06-01

    Neurosyphilis is still a significant medical problem in developing countries and syphilitic ocular manifestations are often not diagnosed due to the lack of typical characteristics. We describe the case of a 59-year-old homosexual man with a 1-month history of decreased vision acuity in his left eye who was diagnosed with neurosyphilis and received treatment with intravenous penicillin G (16 million units in divided daily doses), with great improvement of visual acuity and CSF examination findings. The interest of this case is not only represented by the unusually early ocular involvement, but also by the rapid evolution of the disease into the secondary stage in a man who had had one at-risk homosexual relationship only 3 months before the onset symptoms. We also support the view that the presence of ocular involvement in syphilitic patients is suggestive of involvement of the CNS and should be considered synonymous with neurosyphilis.

  3. The First Case of Vestibulocochlear Neuritis in a Patient with Acquired Immunodeficiency Syndrome in Korea

    PubMed Central

    Park, Hyun Joo; Cho, Chin Saeng; Kim, Nak Min; Yun, Su A

    2016-01-01

    The incidence of human immunodeficiency virus (HIV) infections continue to increase throughout the world. Although neurologic complications are frequent in individuals with HIV infection or acquired immunodeficiency syndrome (AIDS), vestibulocochlear neuritis is still a relatively rare manifestation. We report the first case of vestibulocochlear neuritis occurring in an AIDS patient in Korea. PMID:27433384

  4. Signal measurement system for intra-body communication using optical isolation method

    NASA Astrophysics Data System (ADS)

    Matsumoto, Kazuki; Katsuyama, Jun; Sugiyama, Ryo; Takizawa, Yasuaki; Ishii, Seita; Shinagawa, Mitsuru; Kado, Yuichi

    2014-09-01

    In this paper, we describe an induced signal measurement on the human body for developing a high-performance transceiver of an intra-body communication system. It is important to isolate awearable transceiver from an electrical instrument for precise measurement. We have developed a probe system using an optical isolation method including a laser diode, photo-diode, and optical fiber. The probe system can be successfully applied to the precise measurement of a receiving signal power at a wearable transceiver. We verify that the experimental results agree with the simulation results based on our previous channel model of intra-body communication.

  5. Demonstration of an Optical Isolator with a Semiconductor Guiding Layer that was Obtained by Use of a Nonreciprocal Phase Shift.

    PubMed

    Yokoi, H; Mizumoto, T; Shinjo, N; Futakuchi, N; Nakano, Y

    2000-11-20

    We present the experimental study of an optical isolator with a semiconductor guiding layer that was obtained by use of a nonreciprocal phase shift. The isolator is equipped with an optical interferometer composed of tapered couplers, nonreciprocal phase shifters, and a reciprocal phase shifter. The nonreciprocal phase shifter was constructed by wafer direct bonding between the semiconductor guiding layer and the magneto-optic cladding layer. The isolator, designed for the 1.55-mum wavelength, was fabricated to investigate the characteristics of each component. By applying an external magnetic field to the nonreciprocal phase shifter, we achieved an isolation ratio of approximately 4.9 dB in the interferometric isolator.

  6. Integrated framework for jitter analysis combining disturbance, structure, vibration isolator and optical model

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Oen; Yoon, Jae-San; Han, Jae-Hung

    2012-04-01

    Micro-vibration induced by actuating components of the satellite can severely degrade the optical performance of high precision observation satellites. In this paper, an integrated analysis framework combining disturbance, structure, vibration isolator and optical system model is developed for evaluating the performance of optical payloads in the presence of micro-vibration, and the effectiveness of using a vibration isolator for performance enhancement. Reaction wheel generated disturbance, usually the largest anticipated disturbance, is modeled including the disturbances' interaction with the structural modes of the wheel. For structure modeling, a finite element program is used to solve for eigenvalues and eigenvectors of a structure model which are then used to create a state space model in modal form. A vibration isolator model capturing dynamics of an active isolator utilizing piezoelectric based actuator and load cell for feedback control is included to reduce the transmission of reaction wheel disturbances to the base structure. Dynamic response of the structure to reaction wheel disturbances is calculated with and without vibration isolator. The resulting jitter is used to obtain modulation transfer function (MTF) of diffraction limited optical system model, and the obtained MTF is used as spatial frequency filter for image simulation.

  7. Optical isolator using an atomic vapor in the hyperfine Paschen-Back regime.

    PubMed

    Weller, L; Kleinbach, K S; Zentile, M A; Knappe, S; Hughes, I G; Adams, C S

    2012-08-15

    A light, compact optical isolator using an atomic vapor in the hyperfine Paschen-Back regime is presented. Absolute transmission spectra for experiment and theory through an isotopically pure 87Rb vapor cell show excellent agreement for fields of 0.6 T. We show π/4 rotation for a linearly polarized beam in the vicinity of the D2 line and achieve an isolation of 30 dB with a transmission >95%.

  8. Single-mode waveguide optical isolator based on direction-dependent cutoff frequency.

    PubMed

    Tang, Lingling; Drezdzon, Samuel M; Yoshie, Tomoyuki

    2008-09-29

    A single-mode-waveguide optical isolator based on propagation direction dependent cut-off frequency is proposed. The isolation bandwidth is the difference between the cut-off frequencies of the lowest forward and backward propagating modes. Perturbation theory is used for analyzing the correlation between the material distribution and the bandwidth. The mode profile determines an appropriate distribution of non-reciprocal materials.

  9. All-fiber optical isolator based on Faraday rotation in highly terbium-doped fiber

    SciTech Connect

    Sun, L.; Jiang, S.; Zuegel, J. D.; Marciante, J. R.

    2010-01-01

    An all-fiber isolator with 17 dB optical isolation is demonstrated. The fiber Faraday rotator uses 56 wt. % terbium (Tb)-doped silicate fiber, and the fiber polarizers are Corning SP1060 single-polarization fiber. Finally, the effective Verdet constant of the Tb-doped fiber is measured to be -24.5±1.0 rad/(Tm) at 1053 nm, which is 20 times larger than silica fiber and 22% larger than previously reported results.

  10. All-fiber optical isolator based on Faraday rotation in highly terbium-doped fiber.

    PubMed

    Sun, L; Jiang, S; Zuegel, J D; Marciante, J R

    2010-03-01

    An all-fiber isolator with 17 dB optical isolation is demonstrated. The fiber Faraday rotator uses 56 wt. % terbium (Tb)-doped silicate fiber, and the fiber polarizers are Corning SP1060 single-polarization fiber. The effective Verdet constant of the Tb-doped fiber is measured to be -24.5+/-1.0 rad/(Tm) at 1053 nm, which is 20 times larger than silica fiber and 22% larger than previously reported results.

  11. Design and error analysis of adjustable reflection-type magneto-optical photonic crystals for optical isolator application

    NASA Astrophysics Data System (ADS)

    Zamani, Mehdi; Ghanaatshoar, Majid

    2014-05-01

    We have performed a theoretical study on the case of reflection-type one-dimensional magnetophotonic crystals (MPCs) to establish a practical magneto-optical isolator (MOI). We have introduced thin MPC structures with concurrent high reflectance and large Kerr rotation for oblique incidence, and with the capability of being adjusted to perfect MOIs. It has been shown that the adjustment technique can also provide a framework for establishment of MPCs which are stable against fabrication and setup errors.

  12. Optical isolation in the LIGO gravitational wave laser detector in transient states

    SciTech Connect

    Soloviev, A A; Khazanov, Efim A

    2012-04-30

    This paper presents a numerical analysis of the degree of optical isolation of the laser source by the Faraday isolator in transient states of the laser interferometer gravitational wave observatory (LIGO) detector. This system may be in transient states where the power of the light reflected from the detector to the laser source can exceed many times the power of the source. The present results can be used to analyse the need for installing an additional active mechanical isolation of the source and to evaluate its response time.

  13. Intraobserver reliability of posturography in patients with vestibular neuritis.

    PubMed

    Schwesig, René; Fischer, David; Becker, Stephan; Lauenroth, Andreas

    2014-03-01

    The aim of the study was to establish the intraobserver reliability of a posturographic method in patients (n = 34) with vestibular neuritis. Intraclass correlation coefficients (relative reliability) for all parameters and test positions (ALL(mean)) ranged from 0.71 (95% CI: 0.41-0.85) to 0.92 (95% CI: 0.84-0.96). Absolute reliability (coefficient of variation) ranged between 3.1% (95% CI: 2.60-8.67) and 42.3% (95% CI: 40.7-74.5). Reliability of single test positions is much lower. The posturographic system showed good relative and satisfactory absolute intraobserver reliability for ALL(mean).

  14. Isolation of intact astrocytes from the optic nerve head of adult mice.

    PubMed

    Choi, Hee Joo; Sun, Daniel; Jakobs, Tatjana C

    2015-08-01

    The astrocytes of the optic nerve head are a specialized subtype of white matter astrocytes that form the direct cellular environment of the unmyelinated ganglion cell axons. Due to their potential involvement in glaucoma, these astrocytes have become a target of research. Due to the heterogeneity of the optic nerve tissue, which also contains other cell types, in some cases it may be desirable to conduct gene expression studies on small numbers of well-characterized astrocytes or even individual cells. Here, we describe a simple method to isolate individual astrocytes. This method permits obtaining astrocytes with intact morphology from the adult mouse optic nerve and reduces contamination of the isolated astrocytes by other cell types. Individual astrocytes can be recognized by their morphology and collected under microscopic control. The whole procedure can be completed in 2-3 h. We also discuss downstream applications like multiplex single-cell PCR and quantitative PCR (qPCR).

  15. Controllable optical phase shift over one radian from a single isolated atom.

    PubMed

    Jechow, A; Norton, B G; Händel, S; Blūms, V; Streed, E W; Kielpinski, D

    2013-03-15

    Fundamental optics such as lenses and prisms work by applying phase shifts of several radians to incoming light, and rapid control of such phase shifts is crucial to telecommunications. However, large, controllable optical phase shifts have remained elusive for isolated quantum systems. We have used a single trapped atomic ion to induce and measure a large optical phase shift of 1.3±0.1 radians in light scattered by the atom. Spatial interferometry between the scattered light and unscattered illumination light enables us to isolate the phase shift in the scattered component. The phase shift achieves the maximum value allowed by atomic theory over the accessible range of laser frequencies, pointing out new opportunities in microscopy and nanophotonics. Single-atom phase shifts of this magnitude open up new quantum information protocols, in particular long-range quantum phase-shift-keying cryptography.

  16. Optical isolator based on the electro-optic effect in periodically poled lithium niobate with the addition of a half domain.

    PubMed

    Shi, Lei; Tian, Linghao; Chen, Xianfeng

    2012-12-20

    We propose an optical isolator based on the electro-optic (EO) effect of periodically poled lithium niobate (PPLN). When the EO effect occurs in PPLN under a TE field, each domain serves as a half-wave plate under the quasi-phase-matching condition, and PPLN shows optical activity similar to quartz. The introduction of an additional half-domain to the normal PPLN changes the incident azimuth angle of the reflected light. As a result, the reflected light does not return to the original polarization state. Thus, the optical rotation accumulates and optical isolation occurs. The isolator can be employed for all linearly polarized light and has the advantage of being used in a weak-light system with low driving voltage and high isolation contrast.

  17. Ultraviolet-visible optical isolators based on CeF{sub 3} Faraday rotator

    SciTech Connect

    Víllora, Encarnación G. Shimamura, Kiyoshi; Plaza, Gustavo R.

    2015-06-21

    The first ultraviolet (UV) and visible optical isolators based on CeF{sub 3} are demonstrated. CeF{sub 3} possesses unique properties as Faraday rotator for the UV-visible wavelength region: a wide transparency range (wavelength of >300 nm) and an outstanding Verdet constant. In contrast, currently used terbium-gallium garnets and magneto-optical glasses possess a low transparency in the visible and a small Verdet constant in the UV, respectively. The optical isolator prototypes consist of a CeF{sub 3} rod, a single ring magnet, and a couple of beam splitters. The ring magnets have been designed to guarantee a homogeneous magnetic field; for it, numerical simulations have been carried out. The two prototypes are very compact and operate in the UV at 355 and in the visible at 405 nm, respectively. The performance of these devices indicates the high potential of CeF{sub 3} as a new UV-visible Faraday rotator, specially for shorter wavelengths where at present there are no optical isolators available.

  18. Demonstration of a chip-based optical isolator with parametric amplification

    NASA Astrophysics Data System (ADS)

    Hua, Shiyue; Wen, Jianming; Jiang, Xiaoshun; Hua, Qian; Jiang, Liang; Xiao, Min

    2016-11-01

    Despite being fundamentally challenging in integrated (nano)photonics, achieving chip-based light non-reciprocity becomes increasingly urgent in signal processing and optical communications. Because of material incompatibilities in conventional approaches based on the Faraday effect, alternative solutions have resorted to nonlinear processes to obtain one-way transmission. However, dynamic reciprocity in a recent theoretical analysis has pinned down the functionalities of these nonlinear isolators. To bypass such dynamic reciprocity, we here demonstrate an optical isolator on a silicon chip enforced by phase-matched parametric amplification in four-wave mixing. Using a high-Q microtoroid resonator, we realize highly non-reciprocal transport at the 1,550 nm wavelength when waves are injected from both directions in two different operating configurations. Our design, compatible with current complementary metal-oxide-semiconductor (CMOS) techniques, yields convincing isolation performance with sufficiently low insertion loss for a wide range of input power levels. Moreover, our work demonstrates the possibility of designing chip-based magnetic-free optical isolators for information processing and laser protection.

  19. Demonstration of a chip-based optical isolator with parametric amplification.

    PubMed

    Hua, Shiyue; Wen, Jianming; Jiang, Xiaoshun; Hua, Qian; Jiang, Liang; Xiao, Min

    2016-11-25

    Despite being fundamentally challenging in integrated (nano)photonics, achieving chip-based light non-reciprocity becomes increasingly urgent in signal processing and optical communications. Because of material incompatibilities in conventional approaches based on the Faraday effect, alternative solutions have resorted to nonlinear processes to obtain one-way transmission. However, dynamic reciprocity in a recent theoretical analysis has pinned down the functionalities of these nonlinear isolators. To bypass such dynamic reciprocity, we here demonstrate an optical isolator on a silicon chip enforced by phase-matched parametric amplification in four-wave mixing. Using a high-Q microtoroid resonator, we realize highly non-reciprocal transport at the 1,550 nm wavelength when waves are injected from both directions in two different operating configurations. Our design, compatible with current complementary metal-oxide-semiconductor (CMOS) techniques, yields convincing isolation performance with sufficiently low insertion loss for a wide range of input power levels. Moreover, our work demonstrates the possibility of designing chip-based magnetic-free optical isolators for information processing and laser protection.

  20. Demonstration of a chip-based optical isolator with parametric amplification

    PubMed Central

    Hua, Shiyue; Wen, Jianming; Jiang, Xiaoshun; Hua, Qian; Jiang, Liang; Xiao, Min

    2016-01-01

    Despite being fundamentally challenging in integrated (nano)photonics, achieving chip-based light non-reciprocity becomes increasingly urgent in signal processing and optical communications. Because of material incompatibilities in conventional approaches based on the Faraday effect, alternative solutions have resorted to nonlinear processes to obtain one-way transmission. However, dynamic reciprocity in a recent theoretical analysis has pinned down the functionalities of these nonlinear isolators. To bypass such dynamic reciprocity, we here demonstrate an optical isolator on a silicon chip enforced by phase-matched parametric amplification in four-wave mixing. Using a high-Q microtoroid resonator, we realize highly non-reciprocal transport at the 1,550 nm wavelength when waves are injected from both directions in two different operating configurations. Our design, compatible with current complementary metal-oxide-semiconductor (CMOS) techniques, yields convincing isolation performance with sufficiently low insertion loss for a wide range of input power levels. Moreover, our work demonstrates the possibility of designing chip-based magnetic-free optical isolators for information processing and laser protection. PMID:27886189

  1. Cell manipulation tool with combined microwell array and optical tweezers for cell isolation and deposition

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolin; Gou, Xue; Chen, Shuxun; Yan, Xiao; Sun, Dong

    2013-07-01

    Isolation from rare cells and deposition of sorted cells with high accuracy for further study are critical to a wide range of biomedical applications. In the current paper, we report an automated cell manipulation tool with combined optical tweezers and a uniquely designed microwell array, which functions for recognition, isolation, assembly, transportation and deposition of the interesting cells. The microwell array allows the passive hydrodynamic docking of cells, while offering the opportunity to inspect the interesting cell phenotypes with high spatio-temporal resolution based on the flexible image processing technique. In addition, dynamic and parallel cell manipulation in three dimensions can realize the target cell levitation from microwell and pattern assembly with multiple optical traps. Integrated with the programmed motorized stage, the optically levitated and assembled cells can be transported and deposited to the predefined microenvironment, so the tool can facilitate the integration of other on-chip functionalities for further study without removing these isolated cells from the chip. Experiments on human embryonic stem cells and yeast cells are performed to demonstrate the effectiveness of the proposed cell manipulation tool. Besides the application to cell isolation and deposition, three other biological applications with this tool are also presented.

  2. Optical isolator based on nonreciprocal coupling of two Tamm plasmon polaritons

    NASA Astrophysics Data System (ADS)

    Fang, Yun-Tuan; Zheng, Jing

    2014-12-01

    In this paper, we have studied the one-dimensional photonic crystal (PC) including a magneto-optical metal defect using the developed transfer matrix method for magnetic materials. Around the two interfaces between metal and one-dimensional PC, two nonsymmetric Tamm magneto-plasmon polaritons may be excited and coupled. The coupled states take on a clear nonreciprocal behavior and result in nonreciprocal transmission. The results are demonstrated through electromagnetic field distribution simulations based on finite element software. It provides a useful reference to realize optical isolator design.

  3. The Optical Counterpart of the Isolated Neutron Star RX J1605.3+3249

    NASA Astrophysics Data System (ADS)

    Kaplan, D. L.; Kulkarni, S. R.; van Kerkwijk, M. H.

    2003-05-01

    We have detected the optical counterpart to the nearby isolated neutron star RX J1605.3+3249 using observations from the Space Telescope Imaging Spectrometer aboard the Hubble Space Telescope. The counterpart, with m50CCD=26.84+/-0.07 mag and very blue colors, lies close to the ROSAT HRI error circle and within the Chandra error circle. The spectrum is consistent with a Rayleigh-Jeans tail whose emission is a factor of ~14 above the extrapolation of the X-ray blackbody, and the source has an unabsorbed X-ray-to-optical flux ratio of log(fX/fopt)=4.4, similar to that of other isolated neutron stars. This confirms the classification of RX J1605.3+3249 as a neutron star.

  4. Influence of body laterality on recovery from subjective visual vertical tilt after vestibular neuritis.

    PubMed

    Toupet, Michel; Van Nechel, Christian; Bozorg Grayeli, Alexis

    2014-01-01

    The subjective visual vertical (SVV) is an indicator of vestibular otolithic function and mainly processed by the nondominant parietal cortex. We investigated the hypothesis that recovery from SVV tilt after vestibular neuritis can be influenced by the body's lateral preference. This prospective cohort follow-up study included 254 consecutive adult patients with vestibular neuritis. The recovery from SVV tilt was faster in patients with a left hand or eye dominance than in those with a right dominance. While in left-handers the side of the neuritis did not affect the speed of recovery, in right-handed subjects, the recovery from a right-sided neuritis was significantly slower than from a left-sided affection. These observations suggest that subjects with a left sensorimotor dominance have developed more significant midline-crossing projections to the parietal cortex, allowing them to cope faster with a unilateral vestibular deficit.

  5. Optic Nerve.

    PubMed

    Gordon, Lynn K

    2016-10-28

    Optic nerve diseases arise from many different etiologies including inflammatory, neoplastic, genetic, infectious, ischemic, and idiopathic. Understanding some of the characteristics of the most common optic neuropathies along with therapeutic approaches to these diseases is helpful in designing recommendations for individual patients. Although many optic neuropathies have no specific treatment, some do, and it is those potentially treatable or preventable conditions which need to be recognized in order to help patients regain their sight or develop a better understanding of their own prognosis. In this chapter several diseases are discussed including idiopathic intracranial hypertension, optic neuritis, ischemic optic neuropathies, hereditary optic neuropathies, trauma, and primary tumors of the optic nerve. For each condition there is a presentation of the signs and symptoms of the disease, in some conditions the evaluation and diagnostic criteria are highlighted, and where possible, current therapy or past trials are discussed.

  6. Isolated primary central nervous system lymphoma arising from the optic chiasm.

    PubMed

    Vassal, F; Pommier, B; Boutet, C; Forest, F; Campolmi, N; Nuti, C

    2014-12-01

    A 58-year-old previously healthy woman rapidly developed progressive bilateral visual loss. Magnetic resonance imaging revealed a bulging appearance of the optic chiasm, with homogeneous enhancement after gadolinium administration, which suggested an optic glioma or inflammatory disease. In the absence of (para)clinical clues for a specific diagnosis despite extensive investigation, a biopsy of one optic nerve was performed, resulting in a diagnosis of non-Hodgkin B-cell lymphoma. There was no evidence of any other ocular or systemic involvement, therefore the conclusion was that this immunocompetent patient had a primary central nervous system lymphoma isolated in the anterior visual pathway. Treatment included two cycles of polychemotherapy (rituximab, methotrexate, carmustine, etoposide, methylprednisolone), followed by autologous peripheral blood stem cell transplantation and rituximab plus cytarabine consolidation therapy. Subsequently, the patient exhibited significant improvement in vision, and was still disease-free at the 1-year follow-up examination. The aim of the present paper was to provide well-documented clinical, radiological, and intraoperative features of isolated primary malignant lymphoma arising from the anterior visual pathway. A better recognition of this rare pathological entity is necessary for clinicians who may encounter similar presentations, as prompt management is crucial for both a visual and vital prognosis.

  7. Amorphous-Si waveguide on a garnet magneto-optical isolator with a TE mode nonreciprocal phase shift.

    PubMed

    Ishida, Eiichi; Miura, Kengo; Shoji, Yuya; Yokoi, Hideki; Mizumoto, Tetsuya; Nishiyama, Nobuhiko; Arai, Shigehisa

    2017-01-09

    We fabricated a magneto-optical (MO) isolator with a TE mode nonreciprocal phase shift. The isolator is based on a Mach-Zehnder interferometer composed of 3-dB directional couplers, a reciprocal phase shifter, and a nonreciprocal phase shifter. To realize TE mode operation in the optical isolator, we designed a novel waveguide structure composed of a hydrogenated amorphous silicon waveguide with an asymmetric MO garnet lateral clad on a garnet substrate. The isolator operation is successfully demonstrated in a fabricated device showing the different transmittances between forward and backward directions. The maximum isolation of the fabricated isolator is 17.9 dB at a wavelength of 1561 nm for the TE mode.

  8. A circadian rhythm in optic nerve impulses from an isolated eye in darkness.

    NASA Technical Reports Server (NTRS)

    Jacklet, J. W.

    1971-01-01

    Study of the circadian rhythm of optic nerve potentials recorded from the isolated eye of the sea hare Aplysia. The optic nerve activity in constant conditions is found to be clearly circadian and to obey the circadian rule for diurnal animals. In addition, the period length depends on the in vitro culturing solution. In seawater it is about 22 hr, but in culture medium it is 27 hr. The rhythm can be completely phase-shifted in one trial if the phase of the LD 12:12 Zeitgeber is advanced or delayed 4 hr. The rhythm in one eye can be phase-shifted in vivo independently of the other eye and in vitro independently of the rest of the animal. Thus, in the animal, the eye oscillators are, at most, only slightly influenced by each other or by other oscillators in the animal.

  9. Integrated optical isolator based on nonreciprocal-mode cut-off.

    PubMed

    Hemme, H; Dötsch, H; Hertel, P

    1990-06-20

    A concept of an integrated optical isolator is presented which uses the TM(0) mode propagating perpendicular to the in-plane magnetization of a planar magnetooptical waveguide. The cut-off thickness of the waveguide depends on the propagation direction. If the magnetic film has a strong Faraday rotation and is weakly guiding, the cut-off thicknesses for forward and backward propagation differ markedly. Operating close to cut-off yields a large difference between coupling efficiencies to the waveguide for forward and backward propagation.

  10. Influence of thickness error on the operation of adjustable magneto-optical isolators.

    PubMed

    Sharifian, Mahmoodreza; Ghadiri, Hassan; Zamani, Mehdi; Ghanaatshoar, Majid

    2012-07-10

    We have performed a theoretical study on the case of transmission-type one-dimensional magnetophotonic crystals (MPCs) to establish a practical magneto-optical isolator (MOI) that operates properly even in the presence of construction errors. We have introduced a very thin MPC structure with high transmittance and a large Faraday rotation, with the capability of adjusting to a perfect MOI. A minor thickness error for the individual layers of this MOI may take it from being a perfect MOI; however, its adjustability can provide a stable operation against fabrication errors.

  11. Optical map of the Genotype A1 WB C6 Giardia lamblia genome isolate

    PubMed Central

    Perry, Alexander; Morrison, Hilary G.; Adam, Rodney D.

    2017-01-01

    The Giardia lamblia genome consists of 12 Mb divided among 5 chromosomes ranging in size from approximately 1 to 4 Mb. The assembled contigs of the genotype A1 isolate, WB, were previously mapped along the 5 chromosomes on the basis of hybridization of plasmid clones representing the contigs to chromosomes separated by PFGE. In the current report, we have generated an MluI optical map of the WB genome to improve the accuracy of the physical map. This has allowed us to correct several assembly errors and to better define the extent of the subtelomeric regions that are not included in the genome assembly. PMID:21835210

  12. Optical map of the genotype A1 WB C6 Giardia lamblia genome isolate.

    PubMed

    Perry, D Alexander; Morrison, Hilary G; Adam, Rodney D

    2011-12-01

    The Giardia lamblia genome consists of 12 Mb divided among 5 chromosomes ranging in size from approximately 1 to 4 Mb. The assembled contigs of the genotype A1 isolate, WB, were previously mapped along the 5 chromosomes on the basis of hybridization of plasmid clones representing the contigs to chromosomes separated by PFGE. In the current report, we have generated an MluI optical map of the WB genome to improve the accuracy of the physical map. This has allowed us to correct several assembly errors and to better define the extent of the subtelomeric regions that are not included in the genome assembly.

  13. VLT/FORS2 observations of the optical counterpart of the isolated neutron star RBS 1774

    NASA Astrophysics Data System (ADS)

    Mignani, R. P.; Zane, S.; Turolla, R.; Haberl, F.; Cropper, M.; Motch, C.; Treves, A.; Zampieri, L.

    2011-06-01

    Context. The X-ray observations performed with the Röntgen Satellite (ROSAT) have led to the discovery of a group (seven to date) of X-ray dim and radio-silent, middle-aged isolated neutron stars (a.k.a. XDINSs), which are characterised by pure blackbody spectra (kT ≈ 40-100 eV) and long X-ray pulsations (P = 3-12 s), and appear to be endowed with relatively high magnetic fields, (B ≈ 1013-1014 G). Optical observations of XDINSs are important, together with the X-ray ones, for studying the cooling of the neutron star surface and for investigating the relation between XDINSs and other isolated neutron star classes. RBS 1774 is one of the few XDINSs with a candidate optical counterpart, which we discovered with the Very Large Telescope (VLT). Aims: We aim at constraining the optical spectrum of RBS 1774, for which only two B-band flux measurements are available, and to determine whether its optical emission has either a thermal or a non-thermal origin. Methods: We performed deep observations of RBS 1774 in the R band with the VLT to disentangle a non-thermal power-law spectrum from a Rayleigh-Jeans, whose contributions are expected to be very different in the red part of the spectrum. Results: We did not detect the RBS 1774 candidate counterpart down to a 3σ limiting magnitude of R ~ 27. The constraint on its colour, (B - R) ≲ 0.6, rules out its being a background object, positionally coincident with the X-ray source. Our R-band upper limit is consistent with the extrapolation of the B-band flux (assuming a 3σ uncertainty) for a set of power laws Fν ∝ ν-α with spectral indices α ≤ 0.07. If the optical spectrum of RBS 1774 were non-thermal, its power-law slope would be very much unlike those of all isolated neutron stars with non-thermal optical emission, suggesting that it is most likely thermal. For instance, a Rayleigh-Jeans with temperature TO = 11 eV, for an optically emitting radius rO = 15 km and a source distance d = 150 pc, would be

  14. Design of a compact waveguide optical isolator based on multimode interferometers using magneto-optical oxide thin films grown on silicon-on-insulator substrates.

    PubMed

    Shui, Keyi; Nie, Lixia; Zhang, Yan; Peng, Bo; Xie, Jianliang; Deng, Longjiang; Bi, Lei

    2016-06-13

    We report the design of a waveguide optical isolator based on multimode interferometer (MMI) structure using silicon on insulator (SOI) and deposited magneto-optical (MO) thin films. The optical isolator is based on a vertical 1 × 2 SOI MMI utilizing the nonreciprocal phase shift (NRPS) difference of different TM modes of the MO garnet thin film/SOI waveguide. By constructing a silicon/MO thin film/silicon structure, we demonstrate that the NRPS of the fundamental and first order TM modes can show opposite signs for certain device dimensions, therefore significantly reduce the device length. For a 310.42 μm long device, 20 dB isolation bandwidth larger than 1.6 nm with total insertion loss of 0.817 dB is achieved at 1550 nm wavelength. The fabrication tolerances and materials losses are also discussed to satisfy the state-of-the-art fabrication technology and material properties.

  15. Simultaneous measurement and modulation of multiple physiological parameters in the isolated heart using optical techniques

    PubMed Central

    Lee, Peter; Yan, Ping; Ewart, Paul; Kohl, Peter

    2012-01-01

    Whole-heart multi-parametric optical mapping has provided valuable insight into the interplay of electro-physiological parameters, and this technology will continue to thrive as dyes are improved and technical solutions for imaging become simpler and cheaper. Here, we show the advantage of using improved 2nd-generation voltage dyes, provide a simple solution to panoramic multi-parametric mapping, and illustrate the application of flash photolysis of caged compounds for studies in the whole heart. For proof of principle, we used the isolated rat whole-heart model. After characterising the blue and green isosbestic points of di-4-ANBDQBS and di-4-ANBDQPQ, respectively, two voltage and calcium mapping systems are described. With two newly custom-made multi-band optical filters, (1) di-4-ANBDQBS and fluo-4 and (2) di-4-ANBDQPQ and rhod-2 mapping are demonstrated. Furthermore, we demonstrate three-parameter mapping using di-4-ANBDQPQ, rhod-2 and NADH. Using off-the-shelf optics and the di-4-ANBDQPQ and rhod-2 combination, we demonstrate panoramic multi-parametric mapping, affording a 360° spatiotemporal record of activity. Finally, local optical perturbation of calcium dynamics in the whole heart is demonstrated using the caged compound, o-nitrophenyl ethylene glycol tetraacetic acid (NP-EGTA), with an ultraviolet light-emitting diode (LED). Calcium maps (heart loaded with di-4-ANBDQPQ and rhod-2) demonstrate successful NP-EGTA loading and local flash photolysis. All imaging systems were built using only a single camera. In conclusion, using novel 2nd-generation voltage dyes, we developed scalable techniques for multi-parametric optical mapping of the whole heart from one point of view and panoramically. In addition to these parameter imaging approaches, we show that it is possible to use caged compounds and ultraviolet LEDs to locally perturb electrophysiological parameters in the whole heart. PMID:22886365

  16. Isolation of alkaliphilic bacteria for production of high optically pure L-(+)-lactic acid.

    PubMed

    Yokaryo, Hiroto; Tokiwa, Yutaka

    2014-01-01

    Lactic acid bacteria that grow under alkaline conditions (pH 10) were isolated from various sources in Okinawa (Japan). These alkali-tolerant and alkaliphilic bacteria were classified as follows: Microbacterium sp. (1 strain), Enterococcus spp. (9 strains), Alkalibacterium spp. (3 strains), Exiguobacterium spp. (5 strains), Oceanobacillus spp. (3 strains) and Bacillus spp. (7 strains) by 16S rRNA gene sequencing. By fermentation, many strains were able to convert glucose into mainly L-(+)-lactic acid of high optical purity in alkaline broth. This result indicated that valuable L-(+)-lactic acid-producing bacteria could be isolated efficiently by screening under alkaline conditions. Six strains were selected and their ability to produce lactic acid at different initial pH was compared. Enterococcus casseliflavus strain 79w3 gave the highest lactic acid concentration. Lactic acid concentration and productivity were 103 g L(-1) (optical purity of 99.5% as L-isomer) and 2.2 g L(-1) h(-1), respectively when 129 g L(-1) of glucose was used by batch fermentation.

  17. Benign paroxysmal positional vertigo secondary to vestibular neuritis.

    PubMed

    Balatsouras, Dimitrios G; Koukoutsis, George; Ganelis, Panayotis; Economou, Nicolas C; Moukos, Antonis; Aspris, Andreas; Katotomichelakis, Michael

    2014-05-01

    The aim of this study was to present the demographic, pathogenetic and clinical features of benign paroxysmal positional vertigo (BPPV) secondary to vestibular neuritis (VN). The medical records of 22 patients, who presented with BPPV within 12 weeks after the onset of VN, were reviewed. Data of a complete otolaryngological, audiological, neurotologic and imaging evaluation were available for all patients. Two hundred and eighty-four patients with idiopathic BPPV were used as a control group. The patients with BPPV secondary to VN presented the following features, in which they differed from the patients with idiopathic BPPV: (1) a lower mean age; (2) involvement of the posterior semicircular canal; (3) presence of canal weakness; (4) more therapeutic sessions needed for cure and a higher rate of recurrence. It may be, thus, concluded that BPPV associated with VN differs from idiopathic BPPV in regard to several epidemiological and clinical features, it responds less effectively to treatment and may follow a protracted course, having a tendency for recurrence.

  18. Quantitative assessment of canalicular bile formation in isolated hepatocyte couplets using microscopic optical planimetry.

    PubMed Central

    Gautam, A; Ng, O C; Strazzabosco, M; Boyer, J L

    1989-01-01

    Isolated rat hepatocyte couplets (IRHC) are primary units of bile secretion that accumulate fluid in an enclosed canalicular space with time in culture. We have quantitated the rate of canalicular secretion in IRHC cultured for 4-8 h by measuring the change in canalicular space volume by video-microscopic optical planimetry using high resolution Nomarski optics. Electron microscopic morphometric studies revealed significant increases in canalicular membrane area after 4-6 h in culture. Canalicular secretion in basal L-15 medium (3.8 +/- 1.3 fl/min) increased significantly with the choleretic bile salts (10 microM), taurocholate, and ursodeoxycholate (14 +/- 7 fl/min each). Secretion rates after exposure to bile acids correlated directly with the canalicular surface area before stimulation. In contrast, expansion times after stimulation varied inversely with initial canalicular volumes. Ursodeoxycholic acid failed to produce a hypercholeresis at 10-, 100-, or 200-microM concentrations compared with taurocholate, either in normal or taurine-depleted IRHC. The present findings establish that rates of canalicular bile secretion can be quantitated in IRHC by serial optical planimetry, both in the basal state and after stimulation with bile acids. Furthermore, ursodeoxycholate does not acutely induce hypercholeresis at the canalicular level in this model. Rather, both taurocholic and ursodeoxycholic acids induced secretion in proportion to the surface area of the canalicular membrane. The IRHC are a useful model to identify canalicular choleretics and for studies of canalicular bile formation. Images PMID:2913052

  19. Doppler Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Chen, Zhongping; Zhang, Jun

    Noninvasive techniques for imaging in vivo blood flow are of great value to biomedical research and clinical diagnostics where many diseases have a vascular etiology or component. In ophthalmology, many diseases involve disturbances in ocular blood flow, including diabetic retinopathy, low tension glaucoma, anterior ischemic optic neuritis, and macular degeneration. Simultaneous imaging of tissue structure and blood flow could provide critical information for early diagnosis of ocular diseases.

  20. Early and Phasic Cortical Metabolic Changes in Vestibular Neuritis Onset

    PubMed Central

    Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

    2013-01-01

    Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients’ cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients’ subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about

  1. Early and phasic cortical metabolic changes in vestibular neuritis onset.

    PubMed

    Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

    2013-01-01

    Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [(18)F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients' cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients' subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about

  2. Diffractive optical isolator made of high-efficiency dielectric gratings only.

    PubMed

    Glaser, Tilman; Schröter, Siegmund; Bartelt, Hartmut; Fuchs, Hans-Jörg; Kley, Ernst-Bernhard

    2002-06-20

    The working principle of an optical isolator made of two corrugated dielectric gratings is introduced. One grating acts as a polarizer, and the other acts as a quarter-wave plate used in conical incidence converting linearly polarized light into circularly polarized light. Global maxima of diffraction efficiency for surface-corrugated gratings with binary, sinusoidal, and pyramidal ridge shapes with dependence on the material index are identified. Regarding technological feasibility for use in the visible wavelength range, high-frequency gratings with a binary shape were realized. With these gratings, an extinction ratio of more than 40 dB for the polarizer is theoretically possible, and more than 20 dB was experimentally achieved. A good correlation between theoretically calculated efficiencies and birefringences based on rigorous methods and the experimental results is demonstrated.

  3. Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography.

    PubMed

    Bennett, J L; de Seze, J; Lana-Peixoto, M; Palace, J; Waldman, A; Schippling, S; Tenembaum, S; Banwell, B; Greenberg, B; Levy, M; Fujihara, K; Chan, K H; Kim, H J; Asgari, N; Sato, D K; Saiz, A; Wuerfel, J; Zimmermann, H; Green, A; Villoslada, P; Paul, F

    2015-05-01

    Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients' RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies.

  4. Isolating the chiral contribution in optical two-dimensional chiral spectroscopy using linearly polarized light

    NASA Astrophysics Data System (ADS)

    Holdaway, David I. H.; Collini, Elisabetta; Olaya-Castro, Alexandra

    2017-03-01

    The full development of mono- or multi-dimensional time-resolved spectroscopy techniques incorporating optical activity signals has been strongly hampered by the challenge of identifying the small chiral signals over the large achiral background. Here we propose a new methodology to isolate chiral signals removing the achiral background from two commonly used configurations for performing two dimensional optical spectroscopy, known as BOXCARS and GRadient Assisted Photon Echo Spectroscopy (GRAPES). It is found that in both cases an achiral signal from an isotropic system can be completely eliminated by small manipulations of the relative angles between the linear polarizations of the four input laser pulses. Starting from the formulation of a perturbative expansion of the signal in the angle between the beams and the propagation axis, we derive analytic expressions that can be used to estimate how to change the polarization angles of the four pulses to minimize achiral contributions in the studied configurations. The generalization to any other possible experimental configurations has also been discussed. %We derive analytic expressions to changes required to the polarizations in terms of a perturbative expansion in the angle between the beams and the colinear axis. We also numerically estimate higher order coefficients which cover arbitrarily large angles and thus any experimental configuration.

  5. Wideband design of nonreciprocal phase shift magneto-optical isolators using phase adjustment in Mach-Zehnder interferometers.

    PubMed

    Shoji, Yuya; Mizumoto, Tetsuya

    2006-09-20

    A wideband design is proposed for nonreciprocal phase shift magneto-optical isolators based on Mach-Zehnder interferometers. The wavelength dependence of nonreciprocal phase difference between the backward waves propagating in two interferometer arms is compensated for by that of reciprocal phase difference. This is realized by introducing an appropriate phase bias in one of interferometer arms. Two design examples are presented with a backward loss of >30 dB in the wavelength range of 1.40-1.63 microm for a magnetic garnet waveguide isolator and of 1.485-1.630 microm for a Si-wire waveguide isolator.

  6. [Neurological disorders caused by equine herpesvirus type 1 and cauda equina neuritis in horses].

    PubMed

    Sloet van Oldruitenborgh-Oosterbaan, M M; Binkhorst, G J

    1984-12-15

    The differences in aetiology, symptomatology, pathomorphology, diagnosis and therapy between the nervous form (paralytic form) of Equine Herpes Virus, type 1, and Neuritis Caudae Equinae are reviewed. The conclusion is that in most cases it is possible to differentiate between these two clinical syndromes.

  7. Individual sarcomere length determination from isolated cardiac cells using high-resolution optical microscopy and digital image processing.

    PubMed Central

    Roos, K P; Brady, A J

    1982-01-01

    Discrete sarcomere lengths have been determined from dynamically contracting isolated cardiac cells with a high-speed, high-resolution direct optical imaging system. Calcium-tolerant cardiac cells from the rat are isolated by perfusion with collagenase and hyaluronidase. Individual sarcomere lengths can be determined by directly imaging the cell's striation pattern onto a solid-state charge-coupled device (CCD) detector interfaced with a digital computer. The precision of detection in a real light microscopic optical system is discussed in relation to the type of image detector, optical contract enhancement techniques, and digital image processing. The optical performance of the direct striation pattern image apparatus has been determined empirically with test grids under standard bright-field and Nomarski-differential interference contrast (DIC) conditions for application to real muscle imaging. Discrete striation positions of isolated cells have been detected and followed with high precision during phasic contraction-relaxation cycles down to average sarcomere lengths as short as 1.43 +/- 0.053 microns. The maximum rates of contraction and relaxation are rapid and synchronous in time course along the length of the cell. These results indicate that direct optical imaging can provide an accurate means to monitor discrete striations and sarcomere lengths along the length of Ca2+-tolerant heart cells. Images FIGURE 1 FIGURE 4 PMID:7183337

  8. Myelin-phagocytosing macrophages in isolated sciatic and optic nerves reveal a unique reactive phenotype.

    PubMed

    van Rossum, Denise; Hilbert, Sören; Strassenburg, Silke; Hanisch, Uwe-Karsten; Brück, Wolfgang

    2008-02-01

    Macrophages are key effectors in demyelinating diseases of the central and peripheral nervous system by phagocytosing myelin and releasing immunoregulatory mediators. Here, we report on a distinct, a priori anti-inflammatory reaction of macrophages phagocytosing myelin upon contact with damaged nerve tissue. Macrophages rapidly invaded peripheral (sciatic) and central (optic) nerve tissues in vitro, readily incorporated myelin and expressed high levels of phagocytosis-associated molecules (e.g., Fc and scavenger receptors). In contrast, factors involved in antigen presentation (MHC class-II, CD80, CD86) revealed only a restricted expression. In parallel, a highly ordered appearance of cytokines and chemokines was detected. IL-10, IL-6, CCL22, and CXCL1 were immediately but transiently induced, whereas CCL2, CCL11, and TGFbeta revealed more persisting levels. Such a profile would attract neutrophils, monocytes/macrophages, and Th2 cells as well as bias for a Th2-supporting environment. Importantly, proinflammatory/Th1-supporting factors, such as TNFalpha, IL-12p70, CCL3, and CCL5, were not induced. Still the simultaneous presence of TGFbeta and IL-6 could assist Th17 development, further depending on yet not present IL-23. The release pattern was clearly distinct from reactive phenotypes induced in isolated macrophages and microglia upon treatment with IL-4, IL-13, bacterial lipopolysaccharide, IFNgamma, or purified myelin. Nerve-exposed macrophages thus commit to a unique functional orientation.

  9. Synthetic dimensions in integrated photonics: From optical isolation to four-dimensional quantum Hall physics

    NASA Astrophysics Data System (ADS)

    Ozawa, Tomoki; Price, Hannah M.; Goldman, Nathan; Zilberberg, Oded; Carusotto, Iacopo

    2016-04-01

    Recent technological advances in integrated photonics have spurred on the study of topological phenomena in engineered bosonic systems. Indeed, the controllability of silicon ring-resonator arrays has opened up new perspectives for building lattices for photons with topologically nontrivial bands and integrating them into photonic devices for practical applications. Here, we push these developments even further by exploiting the different modes of a silicon ring resonator as an extra dimension for photons. Tunneling along this synthetic dimension is implemented via an external time-dependent modulation that allows for the generation of engineered gauge fields. We show how this approach can be used to generate a variety of exciting topological phenomena in integrated photonics, ranging from a topologically-robust optical isolator in a spatially one-dimensional (1D) ring-resonator chain to a driven-dissipative analog of the 4D quantum Hall effect in a spatially 3D resonator lattice. Our proposal paves the way towards the use of topological effects in the design of novel photonic lattices supporting many frequency channels and displaying higher connectivities.

  10. Optical Coherence Angiographic Demonstration of Retinal Changes From Chronic Optic Neuropathies.

    PubMed

    Chen, John J; AbouChehade, Jackson E; Iezzi, Raymond; Leavitt, Jacqueline A; Kardon, Randy H

    2017-04-01

    Glaucoma causes a decrease in peripapillary perfused capillary density on optical coherence tomography (OCT) angiography. However, other chronic optic neuropathies have not been explored with OCT angiography to see if these changes were specific to glaucoma. The authors evaluated OCT angiography in 10 patients who suffered various kinds of chronic optic neuropathies, including optic neuritis and ischaemic optic neuropathy, and found that all optic neuropathies showed a decrease in peripapillary vessel density on OCT angiography, regardless of the aetiology of the optic neuropathy. The peripapillary vessel loss on OCT angiography correlated well with the areas of retinal nerve fibre layer thinning seen on OCT.

  11. Anterior ischemic optic neuropathy following dengue fever.

    PubMed

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever.

  12. Anterior ischemic optic neuropathy following dengue fever

    PubMed Central

    Ramakrishnan, Reshma; Shrivastava, Saurabh; Deshpande, Shrikant; Patkar, Priyanka

    2016-01-01

    Dengue fever is caused by a flavivirus. This infection is endemic in the tropics and warm temperate regions of the world. Ocular manifestations of dengue fever include subconjunctival, vitreous, and retinal haemorrhages; posterior uveitis; optic neuritis; and maculopathies, haemorrhage, and oedema. However anterior ischemic optic neuropathy is a rare presentation. Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc oedema. Here we present a case of anterior ischemic optic neurapathy associated with dengue fever. PMID:27843231

  13. Isolation of Optically Targeted Single Bacteria by Application of Fluidic Force Microscopy to Aerobic Anoxygenic Phototrophs from the Phyllosphere

    PubMed Central

    Stiefel, Philipp; Zambelli, Tomaso

    2013-01-01

    In their natural environment, bacteria often behave differently than they do under laboratory conditions. To gain insight into the physiology of bacteria in situ, dedicated approaches are required to monitor their adaptations and specific behaviors under environmental conditions. Optical microscopy is crucial for the observation of fundamental characteristics of bacteria, such as cell shape, size, and marker gene expression. Here, fluidic force microscopy (FluidFM) was exploited to isolate optically selected bacteria for subsequent identification and characterization. In this study, bacteriochlorophyll-producing bacteria, which can be visualized due to their characteristic fluorescence in the infrared range, were isolated from leaf washes. Bacterial communities from the phyllosphere were investigated because they harbor genes indicative of aerobic anoxygenic photosynthesis. Our data show that different species of Methylobacterium express their photosystem in planta, and they show a distinct pattern of bacteriochlorophyll production under laboratory conditions that is dependent on supplied carbon sources. PMID:23770907

  14. Subarachnoid block and enlargement of the spinal canal in hypertrophic neuritis.

    PubMed

    De León, G A; Hodges, F J

    1976-06-01

    A case of Dejerine-Sottas hypertrophic neuritis is reported. The patient, a 45-year-old male, suffered from chronic hypertrophic polyneuropathy, abnormal pupils, fasciculations, tremor, back pain, impotence, sphincter disorders, cramps, and lightning pains in the lower extremities. Besides extensive subarachnoid block, there was X-ray evidence of enlargement of the bony spinal canal with scalloping of the lumbar vertebrae. Surgical exploration showed these abnormalities to be due to extreme hypertrophy of the cauda equina. Histologic findings in peripheral nerve and lumbar root biopsies were typical of hypertrophic neuropathy of the onion bulb type. Vertebral changes secondary to hypertrophied nerve roots appear not to have been described before in hypertrophic neuritis; however, knowledge of their possible occurrence may be of practical importance in the management of similar future cases. A simple way of visualizing enlarged peripheral nerves is briefly described.

  15. Elimination of a back-reflected TE mode in a TM-mode optical isolator with a Mach-Zehnder interferometer.

    PubMed

    Yokoi, Hideki; Mizumoto, Tetsuya; Kuroda, Shinpei; Ohtsuka, Takafumi; Nakano, Yoshiaki

    2002-11-20

    Eimination of a back-reflected TE mode traveling in a TM-mode optical isolator was investigated. The optical isolator had a Mach-Zehnder interferometer that included a polarization-dependent reciprocal phase shifter in one of the arms. The reciprocal phase shift was achieved by an optical path difference between the two arms. By adjustment of the length of the reciprocal phase shifter, the interferometer prevented the back-reflected TE mode from coupling into an input port of the isolator. An extinction ratio of more than 18 dB was obtained against the back-reflected TE mode at a wavelength of 1.55 microm.

  16. An in-vacuo optical levitation trap for high-intensity laser interaction experiments with isolated microtargets

    SciTech Connect

    Price, C. J. Giltrap, S.; Stuart, N. H.; Parker, S.; Patankar, S.; Lowe, H. F.; Smith, R. A.; Donnelly, T. D.; Drew, D.; Gumbrell, E. T.

    2015-03-15

    We report on the design, construction, and characterisation of a new class of in-vacuo optical levitation trap optimised for use in high-intensity, high-energy laser interaction experiments. The system uses a focused, vertically propagating continuous wave laser beam to capture and manipulate micro-targets by photon momentum transfer at much longer working distances than commonly used by optical tweezer systems. A high speed (10 kHz) optical imaging and signal acquisition system was implemented for tracking the levitated droplets position and dynamic behaviour under atmospheric and vacuum conditions, with ±5 μm spatial resolution. Optical trapping of 10 ± 4 μm oil droplets in vacuum was demonstrated, over timescales of >1 h at extended distances of ∼40 mm from the final focusing optic. The stability of the levitated droplet was such that it would stay in alignment with a ∼7 μm irradiating beam focal spot for up to 5 min without the need for re-adjustment. The performance of the trap was assessed in a series of high-intensity (10{sup 17} W cm{sup −2}) laser experiments that measured the X-ray source size and inferred free-electron temperature of a single isolated droplet target, along with a measurement of the emitted radio-frequency pulse. These initial tests demonstrated the use of optically levitated microdroplets as a robust target platform for further high-intensity laser interaction and point source studies.

  17. An in-vacuo optical levitation trap for high-intensity laser interaction experiments with isolated microtargets.

    PubMed

    Price, C J; Donnelly, T D; Giltrap, S; Stuart, N H; Parker, S; Patankar, S; Lowe, H F; Drew, D; Gumbrell, E T; Smith, R A

    2015-03-01

    We report on the design, construction, and characterisation of a new class of in-vacuo optical levitation trap optimised for use in high-intensity, high-energy laser interaction experiments. The system uses a focused, vertically propagating continuous wave laser beam to capture and manipulate micro-targets by photon momentum transfer at much longer working distances than commonly used by optical tweezer systems. A high speed (10 kHz) optical imaging and signal acquisition system was implemented for tracking the levitated droplets position and dynamic behaviour under atmospheric and vacuum conditions, with ±5 μm spatial resolution. Optical trapping of 10 ± 4 μm oil droplets in vacuum was demonstrated, over timescales of >1 h at extended distances of ∼40 mm from the final focusing optic. The stability of the levitated droplet was such that it would stay in alignment with a ∼7 μm irradiating beam focal spot for up to 5 min without the need for re-adjustment. The performance of the trap was assessed in a series of high-intensity (10(17) W cm(-2)) laser experiments that measured the X-ray source size and inferred free-electron temperature of a single isolated droplet target, along with a measurement of the emitted radio-frequency pulse. These initial tests demonstrated the use of optically levitated microdroplets as a robust target platform for further high-intensity laser interaction and point source studies.

  18. Optical coherent tomography measurements of the diffusion rate of water and drugs in an isolated and whole cornea

    SciTech Connect

    Larin, Kirill V; Ghosn, M G

    2006-12-31

    The passive diffusion of drugs through the epithelial surfaces of an eye (the most widespread method for medical treatment of various diseases) is considered. The permeability of water and drugs through rabbit cornea was measured in the isolated cornea (separate from an eye) and in the whole cornea. The permeability coefficients of water and dexamethasone were estimated by the method of optical coherence tomography (OCT). Because multiple photon scattering introduces noise and distortions to the OCT signal, measurements were performed at depths up to 500 {mu}m where most likely single scattering of light occurs in cornea. It is shown that the permeability coefficients in the isolated and whole cornea strongly differ from each other. For example, the water permeability in the isolated and whole cornea is (7.09{+-}0.12)x10{sup -5} and (1.71{+-}0.51)x10{sup -5} cm s{sup -1}, respectively. (special issue devoted to multiple radiation scattering in random media)

  19. Ultra-wideband design of waveguide magneto-optical isolator operating in 1.31mum and 1.55mum band.

    PubMed

    Shoji, Yuya; Mizumoto, Tetsuya

    2007-01-22

    The design of an ultra-wideband waveguide magneto-optical isolator is described. The isolator is based on a Mach-Zehnder interferometer employing nonreciprocal phase shift. The ultra-wideband design is realized by adjusting the wavelength dependence of reciprocal phase difference to compensate for that of nonreciprocal phase difference in the backward direction. We obtained the ultra-wideband design that provides isolation > 35dB from 1.25mum to >1.65mum. This is the proposal of magneto-optical isolator that operates both in 1.31mum band and 1.55mum band.

  20. Retinal nerve fiber layer evaluation in multiple sclerosis with spectral domain optical coherence tomography

    PubMed Central

    Khanifar, Aziz A; Parlitsis, George J; Ehrlich, Joshua R; Aaker, Grant D; D’Amico, Donald J; Gauthier, Susan A; Kiss, Szilárd

    2010-01-01

    Purpose: Histopathologic studies have reported retinal nerve fiber layer (RNFL) thinning in various neurodegenerative diseases. Attempts to quantify this loss in vivo have relied on time-domain optical coherence tomography (TDOCT), which has low resolution and requires substantial interpolation of data for volume measurements. We hypothesized that the significantly higher resolution of spectral-domain optical coherence tomography (SDOCT) would better detect RNFL changes in patients with multiple sclerosis, and that RNFL thickness differences between eyes with and without optic neuritis might be identified more accurately. Methods: In this retrospective case series, patients with multiple sclerosis were recruited from the Judith Jaffe Multiple Sclerosis Center at Weill Cornell Medical College in New York. Patients with a recent clinical diagnosis of optic neuritis (less than three months) were excluded. Eyes with a history of glaucoma, optic neuropathy (other than multiple sclerosis-related optic neuritis), age-related macular degeneration, or other relevant retinal and/or optic nerve disease were excluded. Both eyes of each patient were imaged with the Heidelberg Spectralis® HRA + OCT. RNFL and macular thickness were measured for each eye using the Heidelberg OCT software. These measurements were compared with validated published normal values, and were modeled as linear functions of duration of disease. The odds of an optic neuritis diagnosis as a function of RNFL and macular thickness were calculated. Results: Ninety-four eyes were prospectively evaluated using OCT. Ages of patients ranged from 26 to 69 years, with an average age of 39 years. Peripapillary RNFL thinning was demonstrated in multiple sclerosis patients; mean RNFL thickness was 88.5 μm for individuals with multiple sclerosis compared with a reported normal value of 97 μm (P < 0.001). Eyes with a history of optic neuritis had more thinning compared with those without optic neuritis (83.0

  1. Crystal growth and analysis of ohmic contact and magneto-optical isolator properties of cadmium manganese telluride

    NASA Astrophysics Data System (ADS)

    Prakasam, Mythili; Viraphong, Oudomsack; Teulé-Gay, Lionel; Decourt, Rodolphe; Veber, Philippe; Víllora, Encarnación G.; Shimamura, Kiyoshi

    2011-03-01

    Cd1-xMnxTe (x=0.1, 0.3, 0.5, 0.7 and 0.9) (CMT) single crystals were grown by the vertical Bridgman method. The optical studies reveal that with the increase in Mn concentration, the band gap values increase, which is attributed to s, p-d exchange interaction between the band carriers and Mn ions. Faraday rotation angle of the grown CMT (x=0.5) crystals were measured at the following wavelengths: 825, 1060 and 1575 nm. It was inferred that CMT exhibit larger Faraday effect (3-6 times larger than terbium-gallium garnet (TGG) currently used for optical isolators) making it as an efficient material for optical isolator at longer wavelengths. Field-cooled and zero field-cooled magnetizations of CMT were measured as a function of temperature and magnetic field. The spin-glass like behavior of CMT and their tendency to decrease in magnitude with increasing Mn concentration have been analyzed. The metal contacts on the Cd1-xMnxTe (x=0.1, 0.5, 0.7 and 0.9) crystals have been made with various metals and metal alloys to establish the ohmic contact. The detector characteristics of CMT have been tested using γ-rays with 511 keV (22 Na) and 59.5 keV (241 Am).

  2. Transfer of axonally transported phospholipids into myelin isolated from the rabbit optic pathway

    SciTech Connect

    Alberghina, M.; Viola, M.; Giuffrida, A.M.

    1982-02-01

    The contribution of the axonal transport to the biosynthesis of myelin phospholipids was investigated in the rabbit optic pathway. A double labeling technique was used. The same animals were injected with one isotope intravitreally and the other intraventricularly. This procedure allows double labeling of the optic nerves, optic tracts, lateral geniculate bodies (LGB), and superior colliculus (SC). The precursors simultaneously injected were: (1-/sup 14/C)palmitate (15 microCi intravitreally in both eyes or 50 microCi intraventricularly) and (2-/sup 3/H)glycerol (50 microCi intravitreally in both eyes of 100 microCi intraventricularly). Twenty four hours and 10 days after the injections, myelin was purified from pooled optic nerves and optic tracts as well as from pooled LGBs or SCs. The phospholipids were extracted and then separated by thin-layer chromatography; the specific radioactivity of the various classes of phospholipids was determined. Using both administration routes of C- or /sup 3/H-precursors, the distribution of label and specific radioactivity of myelin phospholipids in the retina and in all other optic structures were very similar. Phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine + phosphoinositol were preferentially labeled with both precursors. These results suggest that, in the rabbit optic pathway the phospholipids synthesized in the retinal ganglion cells and transported along the axons, could undergo transaxonal transfer into myelin.

  3. Biometric, optical and physical changes in the isolated human crystalline lens with age in relation to presbyopia.

    PubMed

    Glasser, A; Campbell, M C

    1999-06-01

    The biometric, optical and physical properties of 19 pairs of isolated human eye-bank lenses ranging in age from 5 to 96 years were compared. Lens focal length and spherical aberration were measured using a scanning laser apparatus, lens thickness and the lens surface curvatures were measured by digitizing the lens profiles and equivalent refractive indices were calculated for each lens using this data. The second lens from each donor was used to measure resistance to physical deformation by providing a compressive force to the lens. The lens capsule was then removed from each lens and each measurement was repeated to ascertain what role the capsule plays in determining these optical and physical characteristics. Age dependent changes in lens focal length, lens surface curvatures and lens resistance to physical deformation are described. Isolated lens focal length was found to be significantly linearly correlated with both the anterior and posterior surface curvatures. No age dependent change in equivalent refractive index of the isolated lens was found. Although decapsulating human lenses causes similar changes in focal length to that which we have shown to occur when human lenses are mechanically stretched into an unaccommodated state, the effects are due to nonsystematic changes in lens curvatures. These studies reinforce the conclusion that lens hardening must be considered as an important factor in the development of presbyopia, that age changes in the human lens are not limited to the loss of accommodation that characterizes presbyopia but that the lens optical and physical properties change substantially with age in a complex manner.

  4. Note: a high transmission Faraday optical isolator in the 9.2 μm range.

    PubMed

    Hilico, Laurent; Douillet, Albane; Karr, Jean-Philippe; Tournié, Eric

    2011-09-01

    We have fabricated and characterized an n-doped InSb Faraday isolator in the mid-IR range (9.2 μm). A high isolation ratio (31(2) dB) and low insertion loss (1.9(3) dB) are obtained. Temperature dependance is analyzed. Further possible improvements are discussed, including the realization of a two-stage isolator. A similar design can be used to cover a wide wavelength range (λ ~ 7.5-30 μm).

  5. Value of the video head impulse test in assessing vestibular deficits following vestibular neuritis.

    PubMed

    Bartolomeo, Mickael; Biboulet, Roselyne; Pierre, Guillemette; Mondain, Michel; Uziel, Alain; Venail, Frederic

    2014-04-01

    To evaluate the performance of the video head impulse test (VHIT) in assessing vestibular deficit in vestibular neuritis. Test validation study was conducted in Tertiary referral center. Twenty-nine patients, referred for vestibular neuritis between October 2009 and March 2012, were included. We recorded age, gender, values of caloric deficit (caloric testing), and deficits in semicircular function (VHIT) at initial presentation and at the follow-up visit (1-3 months). Multivariate linear regression analysis was performed to determine variables associated with values of caloric testing at the follow-up visit. Diagnostic values of VHIT were compared with caloric testing data using the receiver-operating characteristic (ROC) curve and subsequent statistical analysis. At the follow-up visit, complete recovery occurred in 31% of cases according to caloric evaluation, and VHIT normalized in 51.8%. Multivariate regression showed that a higher caloric deficit at the follow-up visit was associated with elevated age (p = 0.012) and high caloric deficit at initial presentation (p = 0.042). A lower caloric deficit was associated with normal VHIT results at the follow-up visit (p < 0.001). The ROC curve showed that specificity and sensitivity of VHIT were 100% when the caloric deficit was respectively lower than 40% or higher than 62.5%. At the caloric testing value of 30%, specificity was 100%, sensitivity 68.84%, positive predictive value 100% and negative predictive value 62.5%. VHIT is a fast, convenient and specific test to detect vestibular deficits in vestibular neuritis. However, VHIT lacks sensitivity by comparison with caloric testing, especially for moderate vestibular lesions.

  6. Vertical eye movements during horizontal head impulse test: a new clinical sign of superior vestibular neuritis.

    PubMed

    D'Onofrio, F

    2013-12-01

    In some patients suffering from acute unilateral peripheral vestibular deficit, the head impulse test performed towards the affected side reveals the typical catch-up saccade in the horizontal plane, and an oblique, mostly vertical, upward catch-up saccade after the rotation of the head towards the healthy side. Three cases are reported herein, which have been studied using slow motion video analysis of the eye movements captured by a high-speed webcam (90 fps). The clinical evidence is discussed and a pathophysiological explanation is proposed, consisting in a selective hypofunction of the superior semicircular canal during superior vestibular neuritis.

  7. Cutoff-mesa isolated rib optical waveguide for III-V heterostructure photonic integrated circuits

    DOEpatents

    Vawter, G.A.; Smith, R.E.

    1998-04-28

    A cutoff mesa rib waveguide provides single-mode performance regardless of any deep etches that might be used for electrical isolation between integrated electrooptic devices. Utilizing a principle of a cutoff slab waveguide with an asymmetrical refractive index profile, single mode operation is achievable with a wide range of rib widths and does not require demanding etch depth tolerances. This new waveguide design eliminates reflection effects, or self-interference, commonly seen when conventional rib waveguides are combined with deep isolation etches and thereby reduces high order mode propagation and crosstalk compared to the conventional rib waveguides. 7 figs.

  8. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    NASA Astrophysics Data System (ADS)

    Sloan Roberts, F.; Anderson, Scott L.

    2013-12-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

  9. Cutoff-mesa isolated rib optical waveguide for III-V heterostructure photonic integrated circuits

    DOEpatents

    Vawter, Gregory A.; Smith, Robert E.

    1998-01-01

    A cutoff mesa rib waveguide provides single-mode performance regardless of any deep etches that might be used for electrical isolation between integrated electrooptic devices. Utilizing a principle of a cutoff slab waveguide with an asymmetrical refractive index profile, single mode operation is achievable with a wide range of rib widths and does not require demanding etch depth tolerances. This new waveguide design eliminates reflection effects, or self-interference, commonly seen when conventional rib waveguides are combined with deep isolation etches and thereby reduces high order mode propagation and crosstalk compared to the conventional rib waveguides.

  10. A unilateral optic perineuritis in a teenager - A case report.

    PubMed

    Ameilia, Ahmad; Shatriah, Ismail; Wan-Hitam, Wan Hazabbah; Yunus, Rohaizan

    2015-06-01

    Optic perineuritis is an uncommon inflammatory disorder that involves optic nerve sheath. Numerous case reports have been published on optic perineuritis in adults, the majority of whom had bilateral presentation. There are limited data on optic perineuritis occurring in pediatric patients. We report a teenager who presented with a unilateral sign that mimicked the presentation of optic neuritis. The orbit and brain magnetic resonance imaging confirmed features of unilateral optic perineuritis. She was treated with a high dose of corticosteroids for 2weeks, and her final visual outcome was satisfactory. No signs of relapse were noted during follow-up visits.

  11. Recessive Mutations in RTN4IP1 Cause Isolated and Syndromic Optic Neuropathies

    PubMed Central

    Angebault, Claire; Guichet, Pierre-Olivier; Talmat-Amar, Yasmina; Charif, Majida; Gerber, Sylvie; Fares-Taie, Lucas; Gueguen, Naig; Halloy, François; Moore, David; Amati-Bonneau, Patrizia; Manes, Gael; Hebrard, Maxime; Bocquet, Béatrice; Quiles, Mélanie; Piro-Mégy, Camille; Teigell, Marisa; Delettre, Cécile; Rossel, Mireille; Meunier, Isabelle; Preising, Markus; Lorenz, Birgit; Carelli, Valerio; Chinnery, Patrick F.; Yu-Wai-Man, Patrick; Kaplan, Josseline; Roubertie, Agathe; Barakat, Abdelhamid; Bonneau, Dominique; Reynier, Pascal; Rozet, Jean-Michel; Bomont, Pascale; Hamel, Christian P.; Lenaers, Guy

    2015-01-01

    Autosomal-recessive optic neuropathies are rare blinding conditions related to retinal ganglion cell (RGC) and optic-nerve degeneration, for which only mutations in TMEM126A and ACO2 are known. In four families with early-onset recessive optic neuropathy, we identified mutations in RTN4IP1, which encodes a mitochondrial ubiquinol oxydo-reductase. RTN4IP1 is a partner of RTN4 (also known as NOGO), and its ortholog Rad8 in C. elegans is involved in UV light response. Analysis of fibroblasts from affected individuals with a RTN4IP1 mutation showed loss of the altered protein, a deficit of mitochondrial respiratory complex I and IV activities, and increased susceptibility to UV light. Silencing of RTN4IP1 altered the number and morphogenesis of mouse RGC dendrites in vitro and the eye size, neuro-retinal development, and swimming behavior in zebrafish in vivo. Altogether, these data point to a pathophysiological mechanism responsible for RGC early degeneration and optic neuropathy and linking RTN4IP1 functions to mitochondrial physiology, response to UV light, and dendrite growth during eye maturation. PMID:26593267

  12. Performance improvements of MOEMS-based diffractive arrays: address isolation and optical switching

    NASA Astrophysics Data System (ADS)

    Panaman, Ganesh; Madison, Seth; Sano, Michael; Castracane, James

    2005-01-01

    Micro-Opto-Electro-Mechanical Systems (MOEMS) have found a variety of applications in fields such as telecommunications, spectroscopy and display technology. MOEMS-based optical switching is currently under investigation for the increased flexibility that such devices provide for reconfiguration of the I/O network for inter-chip communication applications. This potential not only adds an additional degree of freedom for adjustment of transmitter/receiver links but also allows for fine alignment of individual channels in the network link. Further, this use of diffractive arrays for specific applications combines beam steering/adjustment capabilities with the inherent wavelength dependence of the diffractive approach for channel separation and de-multiplexing. Research and development has been concentrated on the progression from single MOEMS components to parallel arrays integrated with optical source arrays for a successful feasibility demonstration. Successful development of such an approach will have a major impact of the next generation communication protocols. This paper will focus on the current status of the MOEMS research program for Free Space Optical inter-chip communication at the College of NanoScale Science and Engineering, University at Albany-SUNY (CNSE). New versions of diffractive arrays stemming from the basic MEMS Compound Grating (MCG; patent #5,999,319) have been produced through various fabrication methods including the MUMPs process1. Most MEMS components relying on electrostatic actuation tend to require high actuation voltages (>20V) compared to the typical 5V levels prevalent in conventional integrated circuits. The specific goal is to yield improved performance while minimizing the power consumption of the components. Structural modifications through the variation in the ruling/electrode spacing distance and array wiring layout through individually addressable gratings have been studied to understand effects on the actuation voltage and

  13. Thermo-optically tuned photonic resonators with concurrent electrical connection and thermal isolation

    DOEpatents

    Lentine, Anthony L.; Kekatpure, Rohan Deodatta; Zortman, William A.; Savignon, Daniel J.

    2016-06-14

    A photonic resonator system is designed to use thermal tuning to adjust the resonant wavelength of each resonator in the system, with a separate tuning circuit associated with each resonator so that individual adjustments may be made. The common electrical ground connection between the tuning circuits is particularly formed to provide thermal isolation between adjacent resonators by including a capacitor along each return path to ground, where the presence of the capacitor's dielectric material provides the thermal isolation. The use of capacitively coupling necessarily requires the use of an AC current as an input to the heater element (conductor/resistor) of each resonator, where the RMS value of the AC signal is indicative of the amount of heat that is generated along the element and the degree of wavelength tuning that is obtained.

  14. Method of targeted delivery of laser beam to isolated retinal rods by fiber optics.

    PubMed

    Sim, Nigel; Bessarab, Dmitri; Jones, C Michael; Krivitsky, Leonid

    2011-11-01

    A method of controllable light delivery to retinal rod cells using an optical fiber is described. Photo-induced current of the living rod cells was measured with the suction electrode technique. The approach was tested with measurements relating the spatial distribution of the light intensity to photo-induced current. In addition, the ion current responses of rod cells to polarized light at two different orientation geometries of the cells were studied.

  15. Wideband temperature-compensated optical isolator or circulator configuration using two Faraday elements.

    PubMed

    Buhrer, C F

    1989-11-01

    Two Faraday elements are configured with two linear retardation elements such that the variations in their individual rotations due to wavelength and temperature changes are compensated for. Wideband isolation between 1250 and 1650 nm is demonstrated using 45 degrees and 90 degrees yttrium iron garnet elements and two 45 degrees right-angle glass prisms (n ~ 1.73) that produce approximately 60 degrees linear retardations on total internal reflection.

  16. Complete optical on-chip isolation based on asymmetric stimulated Raman gain/loss.

    PubMed

    Luo, Zhang; Ye, Weimin; Yuan, Xiaodong; Zhu, Zhihong; Zeng, Chun; Ji, Jiarong

    2012-02-15

    In this Letter, we suggest an on-chip integrated isolator based on an add-drop filter with unidirectional Raman-induced gain (or loss). For the steady state, complete one-way propagation for monochromatic signals is realized in the bus waveguide. For transient transmission, the burr is suppressed. And the power consumption is reduced by enhancing the Q factor of the resonator at the control frequency.

  17. Further enhancement of the second-order nonlinear optical (NLO) coefficient and the stability of NLO polymers that contain isolation chromophore moieties by using the "suitable isolation group" concept and the Ar/Ar(F) self-assembly effect.

    PubMed

    Wu, Wenbo; Ye, Cheng; Qin, Jingui; Li, Zhen

    2013-08-01

    For the first time, a series of second-order NLO poly(arylene-ethynylene)s, in which an isolation chromophore was introduced to enhance the NLO coefficients, were successfully designed and synthesized. Thanks to the isolation chromophore, these polymers demonstrated good NLO activities and optical transparency. To further improve the comprehensive performance of the polymers, different isolation groups of various sizes were introduced to subtly modify the structure of the polymers according to the "suitable isolation group" concept. The naphthalene (Np) group was found to be a "suitable isolation group" in this series of polymers and polymer P3 demonstrated the highest d33 value (122.1 pm V(-1)) of these five polymers. Interestingly, polymer P5, which contained a pentafluorophenyl ring as an isolation group, exhibited a much higher NLO effect and stability than polymer P2, which just contained normal phenyl rings as isolation groups (97.2 versus 62.5 pm V(-1)), thus indicating the advantages of the Ar-Ar(F) self-assembly effect in the field of non-linear optics.

  18. Regularization of the spectral singularity in PT-symmetric systems by all-order nonlinearities: Nonreciprocity and optical isolation

    NASA Astrophysics Data System (ADS)

    Liu, Xuele; Gupta, Subhasish Dutta; Agarwal, G. S.

    2014-01-01

    Spectral singularities are ubiquitous with PT symmetry leading to infinite transmission and reflection coefficients. Since physical systems cannot have singularities, these must be the artifact of some missing physics. The singularities imply the divergence of the fields in the medium, thereby breaking the very assumption of the linearity of the medium used to obtain such singularities. We show how the incorporation of the correct all-order nonlinear behavior of the medium regularizes the spectral singularity. The all-order nonlinear PT-symmetric device is shown to exhibit very effective isolation or optical diode action since transmission through such a system is nonreciprocal. In contrast, a linear system or a system with Kerr nonlinearity is known to have only reciprocal transmission.

  19. Common-path Fourier domain optical coherence tomography of irradiated human skin and ventilated isolated rabbit lungs

    NASA Astrophysics Data System (ADS)

    Popp, A.; Wendel, M.; Knels, L.; Knuschke, P.; Mehner, M.; Koch, T.; Boller, D.; Koch, P.; Koch, E.

    2005-08-01

    A compact common path Fourier domain optical coherence tomography (FD-OCT) system based on a broadband superluminescence diode is used for biomedical imaging. The epidermal thickening of human skin after exposure to ultraviolet radiation is measured to proof the feasibility of FD-OCT for future substitution of invasive biopsies in a long term study on natural UV skin protection. The FD-OCT system is also used for imaging lung parenchyma. FD-OCT images of a formalin fixated lung show the same alveolar structure as scanning electron microscopy images. In the ventilated and blood-free perfused isolated rabbit lung FD-OCT is used for real-time cross-sectional image capture of alveolar mechanics throughout tidal ventilation. The alveolar mechanics changing from alternating recruitment-derecruitment at zero positive end-expiratory pressure (PEEP) to persistent recruitment after applying a PEEP of 5 cm H2O is observed in the OCT images.

  20. Ventricular filling slows epicardial conduction and increases action potential duration in an optical mapping study of the isolated rabbit heart

    NASA Technical Reports Server (NTRS)

    Sung, Derrick; Mills, Robert W.; Schettler, Jan; Narayan, Sanjiv M.; Omens, Jeffrey H.; McCulloch, Andrew D.; McCullough, A. D. (Principal Investigator)

    2003-01-01

    INTRODUCTION: Mechanical stimulation can induce electrophysiologic changes in cardiac myocytes, but how mechanoelectric feedback in the intact heart affects action potential propagation remains unclear. METHODS AND RESULTS: Changes in action potential propagation and repolarization with increased left ventricular end-diastolic pressure from 0 to 30 mmHg were investigated using optical mapping in isolated perfused rabbit hearts. With respect to 0 mmHg, epicardial strain at 30 mmHg in the anterior left ventricle averaged 0.040 +/- 0.004 in the muscle fiber direction and 0.032 +/- 0.006 in the cross-fiber direction. An increase in ventricular loading increased average epicardial activation time by 25%+/- 3% (P < 0.0001) and correspondingly decreased average apparent surface conduction velocity by 16%+/- 7% (P = 0.007). Ventricular loading did not significantly alter action potential duration at 20% repolarization (APD20) but did at 80% repolarization (APD80), from 179 +/- 7 msec to 207 +/- 5 msec (P < 0.0001). The dispersion of APD20 was decreased with loading from 19 +/- 2 msec to 13 +/- 2 msec (P = 0.024), whereas the dispersion of APD80 was not significantly changed. These electrophysiologic changes with ventricular loading were not affected by the nonspecific stretch-activated channel blocker streptomycin (200 microM) and were not attributable to changes in myocardial perfusion or the presence of an electromechanical decoupling agent (butanedione monoxime) during optical mapping. CONCLUSION: Acute loading of the left ventricle of the isolated rabbit heart decreased apparent epicardial conduction velocity and increased action potential duration by a load-dependent mechanism that may not involve stretch-activated channels.

  1. An optical spectrum of a large isolated gas-phase PAH cation: C78H26+

    PubMed Central

    Zhen, Junfeng; Mulas, Giacomo; Bonnamy, Anthony; Joblin, Christine

    2016-01-01

    A gas-phase optical spectrum of a large polycyclic aromatic hydrocarbon (PAH) cation - C78H26+- in the 410-610 nm range is presented. This large all-benzenoid PAH should be large enough to be stable with respect to photodissociation in the harsh conditions prevailing in the interstellar medium (ISM). The spectrum is obtained via multi-photon dissociation (MPD) spectroscopy of cationic C78H26 stored in the Fourier Transform Ion Cyclotron Resonance (FT-ICR) cell using the radiation from a mid-band optical parametric oscillator (OPO) laser. The experimental spectrum shows two main absorption peaks at 431 nm and 516 nm, in good agreement with a theoretical spectrum computed via time-dependent density functional theory (TD-DFT). DFT calculations indicate that the equilibrium geometry, with the absolute minimum energy, is of lowered, nonplanar C2 symmetry instead of the more symmetric planar D2h symmetry that is usually the minimum for similar PAHs of smaller size. This kind of slightly broken symmetry could produce some of the fine structure observed in some diffuse interstellar bands (DIBs). It can also favor the folding of C78H26+ fragments and ultimately the formation of fullerenes. This study opens up the possibility to identify the most promising candidates for DIBs amongst large cationic PAHs. PMID:26942230

  2. Optical studies of tissue mitochondrial redox in isolated perfused rat lungs

    NASA Astrophysics Data System (ADS)

    Sepehr, R.; Staniszewski, K.; Jacobs, E. R.; Audi, S.; Ranji, M.

    2012-02-01

    Through the monitoring of the auto-fluorescent mitochondrial metabolic coenzymes, NADH (Nicotinamide Adenine Dinucleotide) and FAD (Flavoprotein Adenine Dinucleotide), the redox state of metabolism can be probed in real time in many intact organs, but its use has not been fully developed in lungs. The ratio of these fluorophores, (NADH/FAD), referred to as the mitochondrial redox ratio (RR), can be used as a quantitative metabolic marker of tissue. We have designed a fluorometer that can be used to monitor lung surface NADH and FAD fluorescence in isolated perfused lungs. Surface fluorescence NADH and FAD signals were acquired in the absence (control) and presence of pentachlorophenol (PCP), rotenone, and potassium cyanide (KCN). Rotenone, an inhibitor of complex I, increased RR by 18%, predominantly due to an increase in NADH signal. KCN, an inhibitor of complex IV reduced the chain and resulted in an increase of 33% in RR, as a result of 23% increase in NADH and 8% in FAD . PCP, an uncoupler which oxidizes the respiratory chain, decreased RR by 18% as a result of 14% decrease in NADH signal and 4% increase in FAD signal. These results demonstrate the ability of surface fluorometry to detect changes in lung tissue mitochondrial redox state in isolated perfused lungs.

  3. Isolation and characterisation of lactic acid bacterium for effective fermentation of cellobiose into optically pure homo L-(+)-lactic acid.

    PubMed

    Abdel-Rahman, Mohamed Ali; Tashiro, Yukihiro; Zendo, Takeshi; Shibata, Keisuke; Sonomoto, Kenji

    2011-02-01

    Effective utilisation of cellulosic biomasses for economical lactic acid production requires a microorganism with potential ability to utilise efficiently its major components, glucose and cellobiose. Amongst 631 strains isolated from different environmental samples, strain QU 25 produced high yields of l-(+)-lactic acid of high optical purity from cellobiose. The QU 25 strain was identified as Enterococcus mundtii based on its sugar fermentation pattern and 16S rDNA sequence. The production of lactate by fermentation was optimised for the E. mundtii QU25 strain. The optimal pH and temperature for batch culturing were found to be 7.0°C and 43°C, respectively. E. mundtii QU 25 was able to metabolise a mixture of glucose and cellobiose simultaneously without apparent carbon catabolite repression. Moreover, under the optimised culture conditions, production of optically pure l-lactic acid (99.9%) increased with increasing cellobiose concentrations. This indicates that E. mundtii QU 25 is a potential candidate for effective lactic acid production from cellulosic hydrolysate materials.

  4. Bilateral simultaneous optic neuropathy in adults: clinical, imaging, serological, and genetic studies.

    PubMed Central

    Morrissey, S P; Borruat, F X; Miller, D H; Moseley, I F; Sweeney, M G; Govan, G G; Kelly, M A; Francis, D A; Harding, A E; McDonald, W I

    1995-01-01

    To elucidate the cause(s) of acute or subacute bilateral simultaneous optic neuropathy (BSON) in adult life, a follow up study of 23 patients was performed with clinical assessment, brain MRI, HLA typing, and mitochondrial DNA analysis. The results of CSF electrophoresis were available from previous investigations in 11 patients. At follow up, five (22%) had developed clinically definite multiple sclerosis, four (17%) had mitochondrial DNA point mutations indicating a diagnosis of Leber's hereditary optic neuropathy (LHON). The remaining 14 patients (61%) still had clinically isolated BSON a mean of 50 months after the onset of visual symptoms: three of 14 (21%) had multiple MRI white matter lesions compatible with multiple sclerosis, three of 14 (21%) had the multiple sclerosis associated HLA-DR15/DQw6 haplotype, and one of seven tested had CSF oligoclonal IgG bands; in total only five (36%) had one or more of these risk factors. The low frequency of risk factors for the development of multiple sclerosis in these 14 patients suggests that few will develop multiple sclerosis with more prolonged follow up. It is concluded that: (a) about 20% of cases of BSON without affected relatives are due to LHON; (b) multiple sclerosis develops after BSON in at least 20% of cases, but the long term conversion rate is likely to be considerably less than the rate of over 70% seen after an episode of acute unilateral optic neuritis in adult life. PMID:7823072

  5. Brachial neuritis or Parsonage-Turner syndrome: A problem of liability. A presentation of 3 cases.

    PubMed

    Rodríguez-Hornillo, M; de la Riva, M C; Ojeda, R

    2016-01-01

    Neuralgic amyotrophy, brachial neuritis or Parsonage-Turner syndrome is a rare neuromuscular involvement of unknown aetiology. When it onsets in connection with a health care act, such as childbirth or surgery, a malpractice argument is often used as a cause of adverse outcome, usually due to an incorrect position of the patient on the operating table, a circumstance which directly involves the anesthesia area. Three cases are presented of Parsonage-Turner syndrome following very different surgery, with different results as regards prognosis. A review and discussion of bibliography is presented on the possibility that such circumstances are the subject of malpractice claims. Special emphasis is placed on the most currently accepted aetiopathogenic theories, and the relationship of this syndrome with the surgical act as a determining medico-legal aspect. Valuation parameters are proposed.

  6. 1.54-microm TM-mode waveguide optical isolator based on the nonreciprocal-loss phenomenon: device design to reduce insertion loss.

    PubMed

    Amemiya, T; Shimizu, H; Yokoyama, M; Hai, P N; Tanaka, M; Nakano, Y

    2007-08-10

    We developed a 1.5-microm band TM-mode waveguide optical isolator that makes use of the nonreciprocal-loss phenomenon. The device was designed to operate in a single mode and consists of an InGaAlAs/InP ridge-waveguide optical amplifier covered with a ferromagnetic MnAs layer. The combination of the optical waveguide and the magnetized ferromagnetic metal layer produces a magneto-optic effect called the nonreciprocal-loss phenomenon--a phenomenon in which the propagation loss of light is larger in backward propagation than it is in forward propagation. We propose the guiding design principle for the structure of the device and determine the optimized structure with the aid of electromagnetic simulation using the finite-difference method. On the basis of the results, we fabricated a prototype device and evaluated its operation. The device showed an isolation ratio of 7.2 dB/mm at a wavelength from 1.53 to 1.55 microm. Our waveguide isolator can be monolithically integrated with other waveguide-based optical devices on an InP substrate.

  7. Development of ferromagnetic spinels for optical isolation at 10. 6. mu. m

    SciTech Connect

    Teegarden, K.J.

    1980-05-01

    Vacuum hot pressing was used to fabricate CdCr/sub 2/S/sub 4/, CdCr/sub 2/Se/sub 4/ and (1-x) CdCr/sub 2/S/sub 4/.x CdCr/sub 2/Se/sub 4/ discs with diameters of 1.25 cm from fine powders and small single crystals to relative densities as high as 99.6%. Optical attenuation coefficients of approx. 1.0 cm/sup -1/ at 10.6 m were obtained for CdCr/sub 2/S/sub 4/, and values of 12.1 cm/sup -1/ and 14.9 cm/sup -1/ for the selenide and sulfur-selenide mixture. Two-and-three-phonon absorption bands were found to limit the transmission of CdCr/sub 2/S/sub 4/ at lambda > 10 ..mu..m. Extrinsic absorption mechanisms caused the higher attenuation coefficients in CdCr/sub 2/Se/sub 4/ and the mixture. The main extrinsic mechanisms at long wavelengths were free carrier absorption (in CdCr/sub 2/Se/sub 4/) and an impurity absorption band at 16.3 ..mu..m due to Cr/sub 2/O/sub 3/. At short wavelengths the attenuation coefficient was dominated by scattering from pores and second phases. Free carrier absorption was found to be induced by free selenium present in the starting powders. Suppression of this absorption was achieved by optimizing the hot-pressing procedure in order to remove free selenium. The presence of pores was attributed to incomplete densification arising from the presence of second phases (CdSe and Cr/sub 2/Se/sub 3/) and the absence of plastic deformation as a densification mechanism. Laser damage thresholds of 250 MWcm/sup -2/ and 100 MWcm/sup -2/ were measured at 10.6 ..mu..m for CdCr/sub 2/S/sub 4/ and CdCr/sub 2/Se/sub 4/, respectively.

  8. A twenty-eight channel coil array for improved optic nerve imaging

    NASA Astrophysics Data System (ADS)

    Merrill, Robb Phillip

    The purpose of this work was to design and construct a radio-frequency coil optimized for imaging the Optic Nerve (ON) on a Siemens 3T magnetic resonance imaging (MRI) scanner. The specific goals were to optimize signal sensitivity from the orbit to the optic chiasm and improve SNR over designs currently in use. The constructed coil features two fiberglass formers that can slide over each other to accommodate any arbitrary head size, while maintaining close coupling near the eyes and around the head in general. This design eliminates the air void regions that occur between the coil elements and the forehead when smaller heads are imaged in one-piece, nonadjustable coil formers. The 28 coil elements were placed using a soccer-ball pattern layout to maximize head coverage. rSNR profiles from phantom imaging studies show that the ON coil provides approximately 55% greater rSNR at the region of the optic chiasm and approximately 400% near the orbits compared to the 12-channel commercial coil. The improved rSNR in the optic nerve region allows performance of high resolution DTI, which provides a qualitative measurement for evaluating optic neuritis. Images from volunteer and patient studies with the ON coil reveal plaques that correspond well with the patient disease history of chronic bilateral optic neuritis. Correspondence of image findings with patient disease histories demonstrates that optic neuritis can be visualized and detected in patients using 3T MRI with advanced imaging coils, providing improved patient care.

  9. Use of a fiber glass optical system to measure the contractile characteristics of a single isolated muscle cell

    NASA Astrophysics Data System (ADS)

    Chen, Chulung; Yin, Shizhuo; Li, Jiang; Yu, Francis T. S.; Cheung, Joseph Y.; Zhang, Xueqian; Lei, Xiaoxiao; Wu, Zhongkong

    1998-05-01

    Cell is the basic structural and fundamental unit of all organisms; the smallest structure capable of performing all the activities vital to life. One goal of current research interest is to learn how the muscle varies the strength of its contraction in response to electric stimuli. A wide variety of techniques have been developed to monitor the mechanical response of isolated cardiac myocytes. Some success has been reported either with the use of intact rat myocytes supported by suction micropipettes or in guinea pig myocytes adhering to glass beams. However, the usual measuring techniques exhibit destructive contact performance on live cells. They could not solve the problem, since the cell may die during or after the time-consuming attachment process at the beginning of each experiment. In contrast, a novel optical system, which consists of a microglass tube with an inner diameter the same size of a real cardiac cell, is proposed to simulate real cell's twitch process. the physical parameters of synthetic cell are well known. By comparing the dynamics of the real cell with that of the simulated cell, the twitch characteristics of the real cell can be measured.

  10. A connection between neurovascular conflicts within the cerebellopontine angle and vestibular neuritis, a case controlled cohort study.

    PubMed

    Loader, B; Linauer, I; Korkesch, S; Krammer-Effenberger, I; Zielinski, V; Schibany, N; Kaider, A; Vyskocil, E; Tscholakoff, D; Franz, P

    2016-10-01

    This retrospective, observer blinded case-control study aims to compare the prevalence of neurovascular conflicts (NVCs) of the vestibulocochlear nerve and the anterior inferior cerebellar artery (AICA) in patients presenting with clinical signs of acute vestibular neuritis with and without subsequent objective vestibular function loss (VFL). 58 acute cases of clinically suspected acute vestibular neuritis were investigated with same day cranial MRI at a tertiary referral centre and compared to 61 asymptomatic controls. The prevalence of NVCs in cases with objective VFL were also compared to cases without VFL. Radiologists described the NVC as "no contact" (Grade 0), "contact < 2 mm" (Grade 1), "contact > 2 mm" (Grade 2) and "vascular loop presence" (Grade 3) without knowledge of neurotological data. Neurotological data was collected without knowledge of MRI findings. Vestibular function was tested by bithermic caloric irrigation. 26 cases (45%) showed caloric VFL (Group A), whereas 32 (55%) exhibited no VFL (Group B). Group A included 13 cases with NVCs (50%), Group B included 26 NVC cases (82%) (p = 0.012) and the control group included 16 individuals (26%) (p < 0.001 for comparison of all 3 groups). Group B had a significantly higher NVC-Grading than Group A (p = 0.009). There was no statistically significant association between NVCs and either SNHL or tinnitus (p > 0.05). Our results suggest that patients presenting with clinical signs of acute vestibular neuritis who show symmetrical caloric vestibular function test results have a significantly higher NVC prevalence in the cerebellopontine angle.

  11. [A case of subacute necrotizing lymphadenitis complicated with brachial plexus neuritis].

    PubMed

    Sugiyama, A; Araki, E; Arakawa, K; Kikuchi, H; Iwaki, T; Yamada, T; Kira, J

    1998-01-01

    gadolinium-enhancement of the right brachial plexus. As a result, her right upper limb paresis was thus considered to have been caused by right brachial plexus neuritis, which was probably associated with histocytic necrotizing lymphadentis. Although acute cerebellar ataxia and meningitis have previously been reported to be complicated with histiocytic necrotizing lymphadenitis, this is the first report to describe the complication of peripheral neuritis with this condition.

  12. Multiple sclerosis presented as clinically isolated syndrome: the need for early diagnosis and treatment

    PubMed Central

    Pelidou, Sigliti-Henrietta; Giannopoulos, Sotirios; Tzavidi, Sotiria; Lagos, Georgios; Kyritsis, Athanassios P

    2008-01-01

    Objective To aid in the timely diagnosis of patients who present with clinically isolated syndrome (CIS). Patients and methods We studied 25 patients (18 women, 7 men), originally presented in our clinic with a CIS suggestive of multiple sclerosis (MS). All patients underwent the full investigation procedure including routine tests, serology, cerebrospinal fluid (CSF) examinations, evoked potentials (EPs), and magnetic resonance imaging (MRI) of brain and cervical spinal cord. Patients were imaged at baseline, and every three months thereafter up to a year. Results The CIS was consisted of optic neuritis in 12 cases, incomplete transverse myelitis (ITM) in 7 cases, Lhermitte sign in 2 cases, internuclear ophthalmoplegia (INO) in 2 cases, mild brainstem syndrome in 1 case, and tonic-clonic seizures in 1 case. Using the baseline and three-month scans 18/25 (72%) patients developed definite MS in one year of follow up while 7 (28%) had no further findings during this observation period. Immunomodulatory treatments were applied to all definite MS patients. Conclusion In light of new treatments available, MRIs at 3 month intervals are helpful to obtain the definite diagnosis of MS as early as possible. PMID:18827858

  13. Candidate isolated neutron stars and other optically blank x-ray fields identified from the rosat all-sky and sloan digital sky surveys

    SciTech Connect

    Agueros, Marcel A.; Anderson, Scott F.; Margon, Bruce; Haberl, Frank; Voges, Wolfgang; Annis, James; Schneider, Donald P.; Brinkmann, Jonathan; /Apache Point Observ.

    2005-11-01

    Only seven radio-quiet isolated neutron stars (INSs) emitting thermal X rays are known, a sample that has yet to definitively address such fundamental issues as the equation of state of degenerate neutron matter. We describe a selection algorithm based on a cross-correlation of the ROSAT All-Sky Survey (RASS) and the Sloan Digital Sky Survey (SDSS) that identifies X-ray error circles devoid of plausible optical counterparts to the SDSS g {approx} 22 magnitudes limit. We quantitatively characterize these error circles as optically blank; they may host INSs or other similarly exotic X-ray sources such as radio-quiet BL Lacs, obscured AGN, etc. Our search is an order of magnitude more selective than previous searches for optically blank RASS error circles, and excludes the 99.9% of error circles that contain more common X-ray-emitting subclasses. We find 11 candidates, nine of which are new. While our search is designed to find the best INS candidates and not to produce a complete list of INSs in the RASS, it is reassuring that our number of candidates is consistent with predictions from INS population models. Further X-ray observations will obtain pinpoint positions and determine whether these sources are entirely optically blank at g {approx} 22, supporting the presence of likely isolated neutron stars and perhaps enabling detailed follow-up studies of neutron star physics.

  14. SPECIAL ISSUE DEVOTED TO MULTIPLE RADIATION SCATTERING IN RANDOM MEDIA: Optical coherent tomography measurements of the diffusion rate of water and drugs in an isolated and whole cornea

    NASA Astrophysics Data System (ADS)

    Larin, Kirill V.; Ghosn, M. G.

    2006-12-01

    The passive diffusion of drugs through the epithelial surfaces of an eye (the most widespread method for medical treatment of various diseases) is considered. The permeability of water and drugs through rabbit cornea was measured in the isolated cornea (separate from an eye) and in the whole cornea. The permeability coefficients of water and dexamethasone were estimated by the method of optical coherence tomography (OCT). Because multiple photon scattering introduces noise and distortions to the OCT signal, measurements were performed at depths up to 500 μm where most likely single scattering of light occurs in cornea. It is shown that the permeability coefficients in the isolated and whole cornea strongly differ from each other. For example, the water permeability in the isolated and whole cornea is (7.09±0.12)×10-5 and (1.71±0.51)×10-5 cm s-1, respectively.

  15. Temperature-stabilized optical isolator for collimated light using (BiLuGd)(3)Fe(5)O(12)/(BiGd)(3)(FeGa)(5)O(12) composite film.

    PubMed

    Matsuda, K; Mlnernoto, H; Kamada, O; Ishlzuka, S

    1988-04-01

    We have fabricated optical isolators whose temperature dependence of the isolation ratio has a stability of <0.2 dB using (BiLuGd)(3)Fe(5)O(12)/(BiGd)(3)(FeGa)(5)0(12) composite film. It has been confirmed that the temperature-dependent forward loss of the isolators originates from the thermal fluctuation of the absorption peak in the films. We have also evaluated the degradation of the isolation ratio for collimated light depending on the incident angle of the collimated light, the incident position with respect to the optic axis, and the wavelength range needed for practical use.

  16. Impaired mental rotation in benign paroxysmal positional vertigo and acute vestibular neuritis

    PubMed Central

    Candidi, Matteo; Micarelli, Alessandro; Viziano, Andrea; Aglioti, Salvatore M.; Minio-Paluello, Ilaria; Alessandrini, Marco

    2013-01-01

    Vestibular processing is fundamental to our sense of orientation in space which is a core aspect of the representation of the self. Vestibular information is processed in a large subcortical–cortical neural network. Tasks requiring mental rotations of human bodies in space are known to activate neural regions within this network suggesting that vestibular processing is involved in the control of mental rotation. We studied whether mental rotation is impaired in patients suffering from two different forms of unilateral vestibular disorders (vestibular neuritis – VN – and Benign Paroxysmal positional Vertigo – BPPV) with respect to healthy matched controls (C). We used two mental rotation tasks in which participants were required to: (i) mentally rotate their own body in space (egocentric rotation) thus using vestibular processing to a large extent and (ii) mentally rotate human figures (allocentric rotation) thus using own body representations to a smaller degree. Reaction times and accuracy of responses showed that VN and BPPV patients were impaired in both tasks with respect to C. Significantly, the pattern of results was similar in the three groups suggesting that patients were actually performing the mental rotation without using a different strategy from the control individuals. These results show that dysfunctional vestibular inflow impairs mental rotation of both own body and human figures suggesting that unilateral acute disorders of the peripheral vestibular input massively affect the cerebral processes underlying mental rotations. PMID:24324422

  17. MS-275, an histone deacetylase inhibitor, reduces the inflammatory reaction in rat experimental autoimmune neuritis.

    PubMed

    Zhang, Z Y; Zhang, Z; Schluesener, H J

    2010-08-11

    Experimental autoimmune neuritis (EAN) is a T cell-mediated autoimmune inflammatory demyelinating disease of the peripheral nervous system and serves as the animal model of human inflammatory demyelinating polyradiculoneuropathies. MS-275, a potent histone deacetylase inhibitor currently undergoing clinical investigations for various malignancies, has been reported to demonstrate promising anti-inflammatory activities. In our present study, MS-275 administration (3.5 mg/kg i.p.) to EAN rats once daily from the appearance of first neurological signs greatly reduced the severity and duration of EAN and attenuated local accumulation of macrophages, T cells and B cells, and demyelination of sciatic nerves. Further, significant reduction of mRNA levels of pro-inflammatory interleukin-1beta, interferon-gamma, interleukine-17, inducible nitric oxide synthase and matrix metalloproteinase-9 was observed in sciatic nerves of MS-275 treated EAN rats. In lymph nodes, MS-275 depressed pro-inflammatory cytokines as well, but increased expression of anti-inflammatory cytokine interleukine-10 and of foxhead box protein3 (Foxp3), a unique transcription factor of regulatory T cells. In addition, MS-275 treatment increased proportion of infiltrated Foxp3(+) cells and anti-inflammatory M2 macrophages in sciatic nerves of EAN rats. In summary, our data demonstrated that MS-275 could effectively suppress inflammation in EAN, through suppressing inflammatory T cells, macrophages and cytokines, and inducing anti-inflammatory immune cells and molecules, suggesting MS-275 as a potent candidate for treatment of autoimmune neuropathies.

  18. Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography

    PubMed Central

    Bennett, JL; de Seze, J; Lana-Peixoto, M; Palace, J; Waldman, A; Schippling, S; Tenembaum, S; Banwell, B; Greenberg, B; Levy, M; Fujihara, K; Chan, KH; Kim, HJ; Asgari, N; Sato, DK; Saiz, A; Wuerfel, J; Zimmermann, H; Green, A; Villoslada, P

    2015-01-01

    Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients’ RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies. PMID:25662342

  19. Perineural Mast Cells Are Specifically Enriched in Pancreatic Neuritis and Neuropathic Pain in Pancreatic Cancer and Chronic Pancreatitis

    PubMed Central

    Wang, Kun; Kehl, Timo; Giese, Nathalia A.; Algül, Hana; Friess, Helmut; Ceyhan, Güralp O.

    2013-01-01

    Background Pancreatic neuritis is a histopathological hallmark of pancreatic neuropathy and correlates to abdominal neuropathic pain sensation in pancreatic adenocarcinoma (PCa) and chronic pancreatitis (CP). However, inflammatory cell subtypes that compose pancreatic neuritis and their correlation to the neuropathic pain syndrome in PCa and CP are yet unknown. Methods Inflammatory cells within pancreatic neuritis lesions of patients with PCa (n = 20) and CP (n = 20) were immunolabeled and colorimetrically quantified with the pan-leukocyte marker CD45, with CD68 (macrophages), CD8 (cytotoxic T-lymphocytes), CD4 (T-helper cells), CD20 (B-lymphocytes), NCL-PC (plasma cells), neutrophil elastase, PRG2 (eosinophils), anti-mast cell (MC) tryptase and correlated to pain sensation. Perineural mast cell subtypes were analyzed by double immunolabeling with MC chymase. Expression and neural immunoreactivity of protease-activated receptor type 1 (PAR-1) and type 2 (PAR-2) were analyzed in PCa and CP and correlated to pain status of the patients. Results In PCa and CP, nerves were predominantly infiltrated by cytotoxic T-lymphocytes (PCa: 35% of all perineural inflammatory cells, CP: 33%), macrophages (PCa: 39%, CP: 33%) and MC (PCa: 21%, CP: 27%). In both entities, neuropathic pain sensation was associated with a specific increase of perineural MC (PCa without pain: 14% vs. PCa with pain: 31%; CP without pain: 19% vs. CP with pain: 34%), not affecting the frequency of other inflammatory cell subtypes. The vast majority of these MC contained MC chymase. PAR-1 and PAR-2 expression did not correlate to the pain sensation of PCa and CP patients. Conclusion Pancreatic neuritis in PC and CP is composed of cytotoxic T-lymphocytes, macrophages and MC. The specific enrichment of MC around intrapancreatic nerves in neuropathic pain due to PCa and CP suggests the presence of MC-induced visceral hypersensitivity in the pancreas. Therefore, pancreatic and enteric neuropathies seem

  20. Chronic symptoms after vestibular neuritis and the high velocity vestibulo-ocular reflex

    PubMed Central

    Patel, Mitesh; Arshad, Qadeer; Roberts, R Edward; Ahmad, Hena; Bronstein, Adolfo M.

    2015-01-01

    Hypothesis As the anterior and posterior semicircular canals are vital to the regulation of gaze stability, particularly during locomotion or vehicular travel, we tested whether the high velocity vestibulo-ocular reflex (VOR) of the three ipsilesional semicircular canals elicited by the modified Head Impulse Test would correlate with subjective dizziness or vertigo scores after vestibular neuritis (VN). Background Recovery following acute VN varies with around half reporting persistent symptoms long after the acute episode. However, an unanswered question is whether chronic symptoms are associated with impairment of the high velocity VOR of the anterior or posterior canals. Methods Twenty patients who had experienced an acute episode of VN at least three months earlier were included in this study. Participants were assessed with the video head impulse test (vHIT) of all six canals, bithermal caloric irrigation, the Dizziness Handicap Inventory (DHI) and the Vertigo Symptoms Scale short-form (VSS). Results Of these 20 patients, 12 felt that they had recovered from the initial episode whereas 8 did not and reported elevated DHI and VSS scores. However, we found no correlation between DHI or VSS scores and the ipsilesional single or combined vHIT gain, vHIT gain asymmetry or caloric paresis. The high velocity VOR was not different between patients who felt they had recovered and patients who felt they had not. Conclusions Our findings suggest that chronic symptoms of dizziness following VN are not associated with the high velocity VOR of the single or combined ipsilesional horizontal, anterior or posterior semicircular canals. PMID:26719963

  1. Corticosteroids and vestibular exercises in vestibular neuritis. Single-blind randomized clinical trial.

    PubMed

    Goudakos, John K; Markou, Konstantinos D; Psillas, George; Vital, Victor; Tsaligopoulos, Miltiadis

    2014-05-01

    IMPORTANCE The management of patients with unilateral acute vestibular neuritis (VN) has not been established to date. OBJECTIVE To compare the use of vestibular exercises vs corticosteroid therapy in the recovery of patients with acute VN. DESIGN, SETTING, AND PARTICIPANTS Prospective, single-blind, randomized clinical trial at a primary referral center. Among all patients with acute vertigo, those having VN were eligible for inclusion in the study. INTERVENTIONS Forty patients with acute VN were randomly assigned to perform vestibular exercises or to receive corticosteroid therapy. After a baseline examination, follow-up evaluations were performed at 1, 6, and 12 months. MAIN OUTCOMES AND MEASURES Efficacy outcomes included clinical, canal, and otolith recovery. Scores on the European Evaluation of Vertigo Scale and the Dizziness Handicap Inventory were used for the evaluation of clinical recovery. Findings of caloric irrigation and vestibular evoked myogenic potentials indicated canal and otolith improvement, respectively. RESULTS Comparing the 2 treatment groups, no statistically significant differences were found in clinical, canal, or otolith recovery. At the 6-month examination, the number of patients with complete disease resolution in the corticosteroids group was significantly higher than that in the vestibular exercises group. However, at the end of the follow-up period, 45%(9 of 20) of patients in the vestibular exercises group and 50% (10 of 20) of patients in the corticosteroids group had complete disease resolution (P > .05). CONCLUSIONS AND RELEVANCE Treating patients who have acute VN with vestibular exercises seems equivalently effective as treating them with corticosteroid therapy in clinical, caloric, and otolith recovery. Corticosteroid therapy seems to enhance earlier complete acute VN resolution, with no added benefit in the long-term prognosis.

  2. Forced Exercise Preconditioning Attenuates Experimental Autoimmune Neuritis by Altering Th1 Lymphocyte Composition and Egress.

    PubMed

    Calik, Michael W; Shankarappa, Sahadev A; Langert, Kelly A; Stubbs, Evan B

    2015-01-01

    A short-term exposure to moderately intense physical exercise affords a novel measure of protection against autoimmune-mediated peripheral nerve injury. Here, we investigated the mechanism by which forced exercise attenuates the development and progression of experimental autoimmune neuritis (EAN), an established animal model of Guillain-Barré syndrome. Adult male Lewis rats remained sedentary (control) or were preconditioned with forced exercise (1.2 km/day × 3 weeks) prior to P2-antigen induction of EAN. Sedentary rats developed a monophasic course of EAN beginning on postimmunization day 12.3 ± 0.2 and reaching peak severity on day 17.0 ± 0.3 (N = 12). By comparison, forced-exercise preconditioned rats exhibited a similar monophasic course but with significant (p < .05) reduction of disease severity. Analysis of popliteal lymph nodes revealed a protective effect of exercise preconditioning on leukocyte composition and egress. Compared with sedentary controls, forced exercise preconditioning promoted a sustained twofold retention of P2-antigen responsive leukocytes. The percentage distribution of pro-inflammatory (Th1) lymphocytes retained in the nodes from sedentary EAN rats (5.1 ± 0.9%) was significantly greater than that present in nodes from forced-exercise preconditioned EAN rats (2.9 ± 0.6%) or from adjuvant controls (2.0 ± 0.3%). In contrast, the percentage of anti-inflammatory (Th2) lymphocytes (7-10%) and that of cytotoxic T lymphocytes (∼20%) remained unaltered by forced exercise preconditioning. These data do not support an exercise-inducible shift in Th1:Th2 cell bias. Rather, preconditioning with forced exercise elicits a sustained attenuation of EAN severity, in part, by altering the composition and egress of autoreactive proinflammatory (Th1) lymphocytes from draining lymph nodes.

  3. Subclinical optic neuropathy in multiple sclerosis. A neuro-ophthalmological investigation by means of visually evoked response, Farnworth-Munsell 100 Hue test and Ishihara test and their diagnostic value.

    PubMed

    Engell, T; Trojaborg, W; Raun, N E

    1987-12-01

    Affection of the optic nerves play a central role in multiple sclerosis (MS) symptomatology. In reported autopsy series the prevalence of optic neuropathy has approached 100%. In the present study subclinical affection of the optic nerves was investigated by visual evoked response (VER), Farnworth-Munsell 100 Hue test (FM 100 Hue test) and Ishihara plates in 17 patients with normal visual acuity and without a history of acute optic neuritis. Optic neuropathy was demonstrated in 72% of the eyes. The occurrence of optic neuropathy was also investigated by the same methods in 16 patients with previous acute optic neuritis, which was bilateral in 5 patients. Affection of the optic nerves was demonstrated in 95% in this group. The affection of also the fellow eye in patients with previous monolateral optic neuritis is unexplained. It may be an analogue to the symmetry of plaques found in the brain and the spinal cord. The cause of this peculiar distribution of lesions is, like the ethiology of MS, unexplained at present. In comparing the different methods of demonstrating optic neuropathy, VER is recommended as the method of choice.

  4. Charging a Battery-Powered Device with a Fiber-Optically Connected Photonic Power System for Achieving High-Voltage Isolation

    SciTech Connect

    Lizon, David C; Gioria, Jack G; Dale, Gregory E; Snyder, Hans R

    2008-01-01

    This paper describes the development and testing of a system to provide isolated power to the cathode-subsystem electronics of an x-ray tube. These components are located at the cathode potential of several hundred kilovolts, requiring a supply of power isolated from this high voltage. In this design a fiber-optically connected photonic power system (PPS) is used to recharge a lithium-ion battery pack, which will subsequently supply power to the cathode-subsystem electronics. The suitability of the commercially available JDSU PPS for this application is evaluated. The output of the ppe converter is characterized. The technical aspects of its use for charging a variety of Li-Ion batteries are discussed. Battery charge protection requirements and safety concerns are also addressed.

  5. [Retrobulbar optic nevritis and chicken pox: a case report in a child].

    PubMed

    Roelandt, V; Fayol, L; Hugonenq, C; Mancini, J; Chabrol, B

    2005-03-01

    We report here the case of a three-year-old boy presenting with an optic neuritis during the invasive phase of a chicken pox. This clinical, infrequent picture, can be directly due to the virus or be secondary to an auto-immune mechanism. The examination of the ocular fundus, the profile of the spinal fluid, the MRI and the measure of visual evoked potential allow to reach diagnosis and to identify the type of lesion. There is no consensus on the treatment of this optic neuritis and the current attitude is therapeutic abstention because of a rapid spontaneous improvement. Cerebellitis, meningitis can also be seen during chicken pox. Their evolution is quickly favorable, not requiring additional exam. Encephalitis can result from an auto-immune lesion of the white matter and require then the use of corticoids with antiviral drugs.

  6. Distortions of the posterior surface in optical coherence tomography images of the isolated crystalline lens: effect of the lens index gradient

    PubMed Central

    Borja, David; Siedlecki, Damian; de Castro, Alberto; Uhlhorn, Stephen; Ortiz, Sergio; Arrieta, Esdras; Parel, Jean-Marie; Marcos, Susana; Manns, Fabrice

    2010-01-01

    We quantify the posterior surface distortions in optical coherence tomography (OCT) images of isolated crystalline lenses. The posterior radius of curvature and asphericity obtained from OCT images acquired with the beam incident first on the anterior, and then the posterior, surface were compared. The results were compared with predictions of a ray-tracing model which includes the index gradient. The results show that the error in the radius of curvature is within the measurement reproducibility and that it can be corrected by assuming a uniform refractive index. However, accurate asphericity values require a correction algorithm that takes into account the gradient. PMID:21258553

  7. Head impulse gain and saccade analysis in pontine-cerebellar stroke and vestibular neuritis

    PubMed Central

    Todd, Michael; Halmagyi, Gabor M.; Aw, Swee

    2014-01-01

    Objective: We sought to quantify and compare angular vestibulo-ocular reflex (aVOR) gain and compensatory saccade properties elicited by the head impulse test (HIT) in pontine-cerebellar stroke (PCS) and vestibular neuritis (VN). Methods: Horizontal HIT was recorded ≤7 days from vertigo onset with dual-search coils in 33 PCS involving the anterior inferior, posterior inferior, and superior cerebellar arteries (13 AICA, 17 PICA, 3 SCA) confirmed by MRI and 20 VN. We determined the aVOR gain and asymmetry, and compensatory overt saccade properties including amplitude asymmetry and cumulative amplitude (ipsilesional trials [I]; contralesional trials [C]). Results: The aVOR gain (normal: 0.96; asymmetry = 2%) was bilaterally reduced, greater in AICA (I = 0.39, C = 0.57; asymmetry = 20%) than in PICA/SCA strokes (I = 0.75, C = 0.74; asymmetry = 7%), in contrast to the unilateral deficit in VN (I = 0.22, C = 0.76; asymmetry = 54%). Cumulative amplitude (normal: 1.1°) was smaller in AICA (I = 4.2°, C = 3.0°) and PICA/SCA strokes (I = 2.1°, C = 3.0°) compared with VN (I = 8.5°, C = 1.3°). Amplitude asymmetry in AICA and PICA/SCA strokes was comparable, but favored the contralesional side in PICA/SCA strokes and the ipsilesional side in VN. Saccade asymmetry <61% was found in 97% of PCS and none of VN. Gain asymmetry <40% was found in 94% of PCS and 10% of VN. Conclusion: HIT gains and compensatory saccades differ between PCS and VN. VN was characterized by unilateral gain deficits with asymmetric large saccades, AICA stroke by more symmetric bilateral gain reduction with smaller saccades, and PICA stroke by contralesional gain bias with the smallest saccades. Saccade and gain asymmetry should be investigated further in future diagnostic accuracy studies. Classification of evidence: This study provides Class II evidence that aVOR testing accurately distinguishes patients with PCS from VN (sensitivity 94%–97%, specificity 90%–100%). PMID:25253747

  8. Changes in resting-state fMRI in vestibular neuritis.

    PubMed

    Helmchen, Christoph; Ye, Zheng; Sprenger, Andreas; Münte, Thomas F

    2014-11-01

    Vestibular neuritis (VN) is a sudden peripheral unilateral vestibular failure with often persistent head movement-related dizziness and unsteadiness. Compensation of asymmetrical activity in the primary peripheral vestibular afferents is accomplished by restoration of impaired brainstem vestibulo-ocular and vestibulo-spinal reflexes, but presumably also by changing cortical vestibular tone imbalance subserving, e.g., spatial perception and orientation. The aim of this study was to elucidate (i) whether there are changes of cerebral resting-state networks with respect to functional interregional connectivity (resting-state activity) in VN patients and (ii) whether these are related to neurophysiological, perceptual and functional parameters of vestibular-induced disability. Using independent component analysis (ICA), we compared resting-state networks between 20 patients with unilateral VN and 20 age- and gender-matched healthy control subjects. Patients were examined in the acute VN stage and after 3 months. A neural network (component 50) comprising the parietal lobe, medial aspect of the superior parietal lobule, posterior cingulate cortex, middle frontal gyrus, middle temporal gyrus, parahippocampal gyrus, anterior cingulate cortex, insular cortex, caudate nucleus, thalamus and midbrain was modulated between acute VN patients and healthy controls and in patients over time. Within this network, acute VN patients showed decreased resting-state activity (ICA) in the contralateral intraparietal sulcus (IPS), in close vicinity to the supramarginal gyrus (SMG), which increased after 3 months. Resting-state activity in IPS tended to increase over 3 months in VN patients who improved with respect to functional parameters of vestibular-induced disability (VADL). Resting-state activity in the IPS was not related to perceptual (subjective visual vertical) or neurophysiological parameters of vestibular-induced disability (e.g., gain of vestibulo-ocular reflex, caloric

  9. Comprehensive analysis of head-shaking nystagmus in patients with vestibular neuritis.

    PubMed

    Lee, Yeo Jin; Shin, Jung Eun; Park, Mun Su; Kim, Jae Myeong; Na, Bo Ra; Kim, Chang-Hee; Park, Hong Ju

    2012-01-01

    Although biphasic head-shaking nystagmus (HSN) is a basic response to head shaking in patients with unilateral vestibular loss, monophasic HSN is commonly seen in patients with dizziness of undetermined etiology. Since the clinical significance of HSN remains unclear, we sought to characterize different types of HSN in patients with vestibular neuritis (VN) during the acute stage (within 7 days after the onset of vertigo) and at follow-up (about 2 months after the onset of vertigo), and to compare HSN and caloric responses. We analyzed HSN, spontaneous nystagmus and caloric tests in 66 patients with VN. Overall, HSN showed high abnormal rates (94 and 89%) during the acute and follow-up stages and could detect vestibular hypofunction even when canal paresis (CP) had normalized at follow-up. All patients in the acute stage and most patients at follow-up showed HSN with the slow phase to the lesioned side (paretic). Biphasic HSN was common at follow-up, and many patients with a monophasic paretic pattern during the acute stage had evolved to a biphasic paretic pattern at follow-up. Initial slow-phase eye velocities (SPVs) in biphasic HSN were larger than those in monophasic HSN at follow-up. Absence of HSN or reversal of its direction was closely related to normalized caloric responses, but SPVs of HSN did not correlate with the severity of CP. These findings indicate that the HSN test is a sensitive detector of vestibular hypofunction upon 2-Hz head rotation. HSN may reveal previous vestibular hypofunction in the 2-Hz frequency range even at follow-up, when caloric responses detecting vestibular hypofunction in the low-frequency range had normalized. The two tests utilize different mechanisms to assess vestibular hypofunction and are complementary. Biphasic paretic HSN is the most common pattern at follow-up and occurs when the initial SPVs induced by head rotation are large enough to induce the adaptation of primary vestibular afferent activity. Monophasic HSN

  10. Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5-3754

    NASA Astrophysics Data System (ADS)

    Mignani, R. P.; Testa, V.; González Caniulef, D.; Taverna, R.; Turolla, R.; Zane, S.; Wu, K.

    2017-02-01

    The `Magnificent Seven' (M7) are a group of radio-quiet isolated neutron stars discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields (B ≈ 1013 G), radiation from these sources is expected to be substantially polarized, independently of the mechanism actually responsible for the thermal emission. A large observed polarization degree (PD) is, however, expected only if quantum-electrodynamic (QED) polarization effects are present in the magnetized vacuum around the star. The detection of a strong linearly polarized signal would therefore provide the first observational evidence of QED effects in the strong-field regime. While polarization measurements in the soft X-rays are not feasible yet, optical polarization measurements are within reach also for quite faint targets, like the M7 which have optical counterparts with magnitudes ≈26-28. Here, we report on the measurement of optical linear polarization for the prototype, and brightest member, of the class, RX J1856.5-3754 (V ˜ 25.5), the first ever for one of the M7, obtained with the Very Large Telescope. We measured a PD = 16.43 ± 5.26 per cent and a polarization position angle PA = 145.39° ± 9.44°, computed east of the North Celestial Meridian. The PD that we derive is large enough to support the presence of vacuum birefringence, as predicted by QED.

  11. SS316 structure fabricated by selective laser melting and integrated with strain isolated optical fiber high temperature sensor

    NASA Astrophysics Data System (ADS)

    Mathew, Jinesh; Havermann, Dirk; Polyzos, Dimitrios; MacPherson, William N.; Hand, Duncan P.; Maier, Robert R. J.

    2015-09-01

    Smart metal having integrated high temperature sensing capability is reported. The SS316 structure is made by additive layer manufacturing via selective laser melting (SLM). Sensor component is embedded in to the structure during the SLM build process. The strain isolated in-fiber Fabry-Perot cavity sensor measures temperature up to 1100 °C inside the metal.

  12. Congenital optic tract hypoplasia.

    PubMed

    Hatsukawa, Yoshikazu; Fujio, Takahiro; Nishikawa, Masanori; Taylor, David

    2015-08-01

    We report a case of isolated unilateral optic tract hypoplasia, described only twice previously. Bilateral optic disk hypoplasia was seen ophthalmoscopically and visual field studies showed an incongruous right homonymous hemianopia. Magnetic resonance imaging showed bilateral hypoplasia of both optic nerves and the left optic tract. Spectral domain optical coherence tomography mapping correlated well with the visual field studies.

  13. Enhanced Emission from Single Isolated Gold Quantum Dots Investigated Using Two-Photon-Excited Fluorescence Near-Field Scanning Optical Microscopy.

    PubMed

    Abeyasinghe, Neranga; Kumar, Santosh; Sun, Kai; Mansfield, John F; Jin, Rongchao; Goodson, Theodore

    2016-12-21

    New approaches in molecular nanoscopy are greatly desired for interrogation of biological, organic, and inorganic objects with sizes below the diffraction limit. Our current work investigates emergent monolayer-protected gold quantum dots (nanoclusters, NCs) composed of 25 Au atoms by utilizing two-photon-excited fluorescence (TPEF) near-field scanning optical microscopy (NSOM) at single NC concentrations. Here, we demonstrate an approach to synthesize and isolate single NCs on solid glass substrates. Subsequent investigation of the NCs using TPEF NSOM reveals that, even when they are separated by distances of several tens of nanometers, we can excite and interrogate single NCs individually. Interestingly, we observe an enhanced two-photon absorption (TPA) cross section for single Au25 NCs that can be attributed to few-atom local field effects and to local field-induced microscopic cascading, indicating their potential for use in ultrasensitive sensing, disease diagnostics, cancer cell therapy, and molecular computers. Finally, we report room-temperature aperture-based TPEF NSOM imaging of these NCs for the first time at 30 nm point resolution, which is a ∼5-fold improvement compared to the previous best result for the same technique. This report unveils the unique combination of an unusually large TPA cross section and the high photostability of Au NCs to (non-destructively) investigate stable isolated single NCs using TPEF NSOM. This is the first reported optical study of monolayer-protected single quantum clusters, opening some very promising opportunities in spectroscopy of nanosized objects, bioimaging, ultrasensitive sensing, molecular computers, and high-density data storage.

  14. Features of anti-aquaporin 4 antibody-seropositive Chinese patients with neuromyelitis optica spectrum optic neuritis.

    PubMed

    Li, Hongyang; Wang, Yanling; Xu, Quangang; Zhang, Aidi; Zhou, Huanfen; Zhao, Shuo; Kang, Hao; Peng, Chunxia; Cao, Shanshan; Wei, Shihui

    2015-10-01

    The detection of anti-aquaporin-4 autoantibody (AQP-4 Ab) is crucial to detect patients who will develop neuromyelitis optica (NMO); however, there are few studies on the AQP-4 Ab serostatus of patients with neuromyelitis optica spectrum ON. We analyzed the clinical and paraclinical features of neuromyelitis optica spectrum ON patients in China according to the patients' AQP4-Ab serostatus. 125 patients with recurrent and bilateral ON with simultaneous attacks were divided into AQP-4 Ab-seropositive and -seronegative groups. Demographic, clinical, serum autoantibody data, connective tissue disorders (CTDs), visual performance were compared. A Visual Acuity (VA) of less than 0.1 during acute ON attacks occurred more frequently in the seropositive group (p = 0.023); however, there was not a significant difference between groups on VA recovery after the first attack. The seropositive group experienced the worst outcome during the last attack (p = 0.017). Other co-existing autoimmunity antibodies (p < 0.001) and CTDs (p < 0.001) were more prevalent in seropositive patients. There were no significant differences on VA recovery and RNFLT combined with other autoantibodies or CTDs. The two groups did not differ significantly with regard to time to relapse, annualized relapse rates, time of diagnosis NMO, or RNFL. There were no significant differences on VA recovery and RNFLT combined with other autoantibodies or CTDs. RNFLT was thinner in NMO seropositive patients. Although AQP-4 Ab expression predicted poor visual outcome, positive patients were usually associated with mild symptoms at first onset. Anti-SSA/SSB antibody or Sjögren syndrome may be associated with AQP-4 Ab in neuromyelitis optica spectrum ON.

  15. The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

    NASA Astrophysics Data System (ADS)

    Wang, Weiyang; Lu, Jiguang; Tong, Hao; Ge, Mingyu; Li, Zhaosheng; Men, Yunpeng; Xu, Renxin

    2017-03-01

    X-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4–4123, with a radiation radius of ∼3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China’s space station around 2020.

  16. Performance of D-criteria in isolating meteor showers from the sporadic background in an optical data set

    NASA Astrophysics Data System (ADS)

    Moorhead, Althea V.

    2016-02-01

    Separating meteor showers from the sporadic meteor background is critical for the study of both showers and the sporadic complex. The linkage of meteors to meteor showers, to parent bodies, and to other meteors is done using measures of orbital similarity. These measures often take the form of so-called D-parameters and are generally paired with some cutoff value within which two orbits are considered related. The appropriate cut-off value can depend on the size of the data set (Southworth & Hawkins 1963), the sporadic contribution within the observed size range (Jopek 1995), or the inclination of the shower (Galligan 2001). If the goal is to minimize sporadic contamination of the extracted shower, the cut-off value should also reflect the strength of the shower compared to the local sporadic background. In this paper, we present a method for determining, on a per-shower basis, the orbital similarity cut-off value that corresponds to a chosen acceptable false-positive rate. This method also assists us in distinguishing which showers are significant within a set of data. We apply these methods to optical meteor observations from the NASA All-Sky and Southern Ontario Meteor Networks.

  17. Theoretical investigations of the optical spectra and EPR parameters for the isolated and pairs of trivalent ytterbium ions in Li6Y(BO3)3 crystal

    NASA Astrophysics Data System (ADS)

    Liu, Hong-Gang; Zheng, Wen-Chen

    2015-11-01

    The optical spectra and electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants A) for an isolated Yb3+ ion in Li6Y(BO3)3 (LYB) crystal are investigated first by the complete diagonalization method based on the superposition model. The obtained results are in reasonable agreement with the experimental ones. For a pair of coupled Yb3+ ions in crystals, the extensively used formulas to calculate EPR splitting lines for such pair cannot be directly adopted in the present study and thus we extend them to the case of arbitrarily directed vector R connecting the two Yb3+ ions in crystal. By these amended formulas, we find that in addition to the interacting Yb3+ pair with nearest distance R (=0.385 nm), the Yb3+ pair with next-nearest distance R (=0.662 nm) would also make contribution to experimental EPR spectra. This point which was not noticed in previous works would help us further understand the energy transfer scheme between two Yb3+ ions in crystals.

  18. Autonomous oscillation/separation of cell density artificially induced by optical interlink feedback as designed interaction between two isolated microalgae chips

    PubMed Central

    Ozasa, Kazunari; Won, June; Song, Simon; Maeda, Mizuo

    2016-01-01

    We demonstrate a designed interaction between two isolated cell populations of Euglena gracilis and Chlamydomonas reinhardtii, separately confined in two 25-square micro-aquariums of lab-on-chip size. The interaction was realized by interlinking two identical optical feedback systems, which measured the cell distribution. To analyze the cell populations, we measured the cell distribution in the 25 squares and irradiated the cells with a blue light pattern as an external stimulus. The cell distribution dataset was exchanged between the two systems. Governed by a designed interaction algorithm, the feedback systems produced a dynamic blue light illumination pattern that evoked the photophobic responses of both species. We also induced autonomous cell density oscillation and cell distribution separation and clustering, and analyzed how the types and diversities of the photophobic responses affected the oscillation period and separation and clustering. We conclude that artificial interlink feedback is a promising method for investigating diverse cell–cell interactions in ecological communities, and for developing soft-computing applications with living cells. PMID:27098710

  19. Autonomous oscillation/separation of cell density artificially induced by optical interlink feedback as designed interaction between two isolated microalgae chips

    NASA Astrophysics Data System (ADS)

    Ozasa, Kazunari; Won, June; Song, Simon; Maeda, Mizuo

    2016-04-01

    We demonstrate a designed interaction between two isolated cell populations of Euglena gracilis and Chlamydomonas reinhardtii, separately confined in two 25-square micro-aquariums of lab-on-chip size. The interaction was realized by interlinking two identical optical feedback systems, which measured the cell distribution. To analyze the cell populations, we measured the cell distribution in the 25 squares and irradiated the cells with a blue light pattern as an external stimulus. The cell distribution dataset was exchanged between the two systems. Governed by a designed interaction algorithm, the feedback systems produced a dynamic blue light illumination pattern that evoked the photophobic responses of both species. We also induced autonomous cell density oscillation and cell distribution separation and clustering, and analyzed how the types and diversities of the photophobic responses affected the oscillation period and separation and clustering. We conclude that artificial interlink feedback is a promising method for investigating diverse cell–cell interactions in ecological communities, and for developing soft-computing applications with living cells.

  20. Relation of video-head-impulse test and caloric irrigation: a study on the recovery in unilateral vestibular neuritis.

    PubMed

    Zellhuber, Stephanie; Mahringer, Andrea; Rambold, Holger A

    2014-09-01

    The head-impulse test (HIT) is an important test for examining unilateral vestibular hypofunction. The new video-head-impulse test (vHIT) is more sensitive and specific than the clinical bedside-head-impulse test. Alternatively, one can test for vestibular hypofunction with the caloric irrigation test. Various studies have shown that both tests may not always identify vestibular hypofunction; instead, the results of the tests might be contradictory. To further explore the question, of whether vHIT and caloric irrigation test the same part of the angular horizontal vestibulo-ocular reflex (VOR), we examined patients with unilateral vestibular neuritis at different points in time. The tonic vestibular imbalance (e.g., subjective-visual-vertical, ocular torsion and spontaneous nystagmus) and dynamic dysfunction of VOR (vHIT and bithermal caloric irrigation) were measured and quantified. While parameters of the tonic vestibular imbalance were well described by single exponential decay functions, dynamic parameters were less well defined. Therefore, to better compare the time course of pairs of two different parameters, we used a linear regression analysis. No linear correlation was found in the group and individually for the gain asymmetry and the ipsilesional gain of the vHIT with the unilateral weakness of the bithermal caloric irrigation tests. Linear correlation was found for most parameters of tonic vestibular imbalance. These findings are further evidence that vHIT and caloric irrigation test different parts of the angular VOR.

  1. Cervical and ocular vestibular-evoked myogenic potentials in vestibular neuritis: comparison between air- and bone-conducted stimulation.

    PubMed

    Oh, Sun-Young; Kim, Ji-Soo; Yang, Tae-Ho; Shin, Byoung-Soo; Jeong, Seul-Ki

    2013-08-01

    To clarify the changes of cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials induced by air-conducted sound (ACS) and bone-conducted vibration (BCV) in patients with vestibular neuritis (VN), patients with VN (n = 30) and normal controls (n = 45) underwent recording of cVEMP and oVEMP in response to ACS (1,000 Hz, 5 ms, tone bursts) and BCV (500 Hz, short tone burst). Patients with VN showed a high proportion of oVEMP abnormalities in response to both ACS (80.0 %) and BCV at the forehead (Fz, 73.3 %) or the mastoid (76.7 %). In contrast, cVEMPs were mostly normal with both ACS and BCV in the patients. The dissociations in the abnormalities of cVEMP and oVEMP induced by ACS and BCV at the mastoids and at the forehead in patients with VN suggest that oVEMP reflects functions of the superior vestibular nerve and most likely the utricular function. The results of our study suggest that oVEMP induced by either ACS or BCV appears to depend on integrity of the superior vestibular nerve, possibly due to the utricular afferents travelling in it. In contrast, cVEMP elicited by either ACS or BCV may reflect function of the saccular afferents running in the inferior vestibular nerve.

  2. Allograft-inflammatory factor-1 in rat experimental autoimmune encephalomyelitis, neuritis, and uveitis: expression by activated macrophages and microglial cells.

    PubMed

    Schluesener, H J; Seid, K; Kretzschmar, J; Meyermann, R

    1998-10-01

    Allograft inflammatory factor-1 (AIF-1) is a Ca2+ binding peptide expressed predominantly by activated monocytes. In order to investigate the role of AIF-1 in autoimmune lesions of the rat nervous system, we have used a synthetic gene to express AIF-1 in E. coli and have produced monoclonal antibodies against AIF-1. AIF-1 was localized to monocytes/macrophages with rather selective staining of a minor rat monocyte subpopulation of lymphoid tissue. We then investigated expression of AIF-1 in experimental autoimmune encephalomyelitis (EAE), neuritis (EAN), and uveitis (EAU). Within the local inflammatory lesions, infiltrating macrophages are prominently stained. In the diseased brain, AIF-1-positive microglial cells are not only found in the direct vicinity of the infiltrate, but widespread activation is seen in the parenchyma. This is the first demonstration that AIF-1 is present in autoimmune lesions. Immunostaining of microglial cells is noteworthy, as these cells are strategically placed regulatory elements of CNS immunosurveillance. Thus, AIF-1 might be a valuable marker to dissect the local monocyte heterogeneity in autoimmune disease.

  3. Aspects of cerebral plasticity related to clinical features in acute vestibular neuritis: a "starting point" review from neuroimaging studies.

    PubMed

    Micarelli, A; Chiaravalloti, A; Schillaci, O; Ottaviani, F; Alessandrini, M

    2016-04-01

    Vestibular neuritis (VN) is one of the most common causes of vertigo and is characterised by a sudden unilateral vestibular failure (UVF). Many neuroimaging studies in the last 10 years have focused on brain changes related to sudden vestibular deafferentation as in VN. However, most of these studies, also due to different possibilities across diverse centres, were based on different times of first acquisition from the onset of VN symptoms, neuroimaging techniques, statistical analysis and correlation with otoneurological and psychological findings. In the present review, the authors aim to merge together the similarities and discrepancies across various investigations that have employed neuroimaging techniques and group analysis with the purpose of better understanding about how the brain changes and what characteristic clinical features may relate to each other in the acute phase of VN. Six studies that strictly met inclusion criteria were analysed to assess cortical-subcortical correlates of acute clinical features related to VN. The present review clearly reveals that sudden UVF may induce a wide variety of cortical and subcortical responses - with changes in different sensory modules - as a result of acute plasticity in the central nervous system.

  4. Detecting Optic Atrophy in Multiple Sclerosis Patients Using New Colorimetric Analysis Software: From Idea to Application.

    PubMed

    Bambo, Maria Pilar; Garcia-Martin, Elena; Perez-Olivan, Susana; Larrosa-Povés, José Manuel; Polo-Llorens, Vicente; Gonzalez-De la Rosa, Manuel

    2016-01-01

    Neuro-ophthalmologists typically observe a temporal pallor of the optic disc in patients with multiple sclerosis. Here, we describe the emergence of an idea to quantify these optic disc color changes in multiple sclerosis patients. We recruited 12 multiple sclerosis patients with previous optic neuritis attack and obtained photographs of their optic discs. The Laguna ONhE, a new colorimetric software using hemoglobin as the reference pigment in the papilla, was used for the analysis. The papilla of these multiple sclerosis patients showed greater pallor, especially in the temporal sector. The software detected the pallor and assigned hemoglobin percentages below normal reference values. Measurements of optic disc hemoglobin levels obtained with the Laguna ONhE software program had good ability to detect optic atrophy and, consequently, axonal loss in multiple sclerosis patients. This new technology is easy to implement in routine clinical practice.

  5. Atypical Presentation of Idiopathic Bilateral Optic Perineuritis in a Young Patient

    PubMed Central

    Tevaraj, Jessica Mani Penny; Mohd-Noor, Raja-Azmi; Thavaratnam, Lakana Kumar; Salmah, Win Mar

    2016-01-01

    A previously healthy 27-year-old Malay male presented with acute onset of painless, severe blurring of vision in his right eye. It was associated with headache and vomiting for the past week. Relative afferent pupillary defect was present in the right eye, with reduced optic nerve function. Patient also had bilateral generalised optic disc swelling, splinter haemorrhages, and tortuous vessels. Initial examination was suggestive of either optic neuritis or raised intracranial pressure. Typical features of bilateral optic perineuritis (OPN) such as tram track and doughnut sign were observed on magnetic resonance imaging. Connective tissue and infective screening were negative. He was diagnosed with bilateral optic perineuritis and treated with high dose intravenous corticosteroids followed by a three-month course of oral steroids. His vision and optic nerve function recovered to baseline levels. PMID:28078151

  6. Attenuation of experimental autoimmune neuritis with locally administered lovastatin-encapsulating poly(lactic-co-glycolic) acid nanoparticles.

    PubMed

    Langert, Kelly A; Goshu, Bruktawit; Stubbs, Evan B

    2017-01-01

    Acute inflammatory demyelinating polyneuropathy (AIDP) is an aggressive antibody- and T-cell-mediated variant of Guillain-Barré Syndrome (GBS), a prominent and debilitating autoimmune disorder of the peripheral nervous system. Despite advancements in clinical management, treatment of patients with AIDP/GBS and its chronic variant CIDP remains palliative and relies on the use of non-specific immunemodulating therapies. Our laboratory has previously reported that therapeutic administration of statins safely attenuates the clinical severity of experimental autoimmune neuritis (EAN), a well-characterized animal model of AIDP/GBS, by restricting the migration of autoreactive leukocytes across peripheral nerve microvascular endoneurial endothelial cells that form the blood-nerve barrier. Despite these advancements, the clinical application of systemically administered statins for the management of inflammatory disorders remains controversial as a result of disappointingly inconclusive phase trials. Here, poly(lactic-co-glycolic) acid (PLGA) nanoparticles were evaluated as an alternative strategy by which to locally administer statins for the management of EAN. When tested in vitro, lovastatin-encapsulating PLGA nanoparticles elicited a marked increase in RhoB mRNA content in peripheral nerve microvascular endoneurial endothelial cells, similar to cells treated with activated unencapsulated lovastatin. Unilateral peri-neural administration of lovastatin-encapsulating PLGA nanoparticles, but not empty nanoparticles, to naïve Lewis rats similarly enhanced RhoB mRNA content in adjacent nerve and muscle tissue. When administered in this manner, serum levels of lovastatin were below the level of detection. Bilateral peri-neural administration of lovastatin-encapsulating PLGA nanoparticles to EAN-induced Lewis rats significantly attenuated EAN clinical severity while protecting against EAN-induced peripheral nerve morphological and functional deficits. This study provides

  7. The role of cervical and ocular vestibular-evoked myogenic potentials in the follow-up of vestibular neuritis.

    PubMed

    Adamec, Ivan; Skorić, Magdalena Krbot; Handžić, Jadranka; Barušić, Anabella Karla; Bach, Ivo; Gabelić, Tereza; Habek, Mario

    2014-04-01

    This study evaluates the recovery of vestibular nerve function after vestibular neuritis (VN) by vestibular-evoked myogenic potentials (VEMPs). Twenty-six patients with the diagnosis of VN were included. All patients underwent ocular VEMP (oVEMP) and cervical VEMP (cVEMP) recordings, at 6 days and 6 months from the onset of the symptoms. Of the 26 patients, 14 showed improvement on oVEMP at month 6 (group 1), and 12 showed no change or worsening on oVEMP at 6 months (group 2). At the same time, there was no change in the amplitudes of the cVEMP on either healthy or affected sides in both groups. Inability to perform the Fukuda test, and chronic white matter supratentorial lesions present on brain magnetic resonance imaging (MRI) were more frequent in patients with worse outcome on oVEMP (P = 0.044 and 0.045, respectively). Although involvement of the inferior branch of the vestibular nerve was not associated with oVEMP outcome, oVEMP latencies (N10 and P13) were associated with improvement or worsening in oVEMP amplitudes, showing that prolonged latencies correlate with 6-month improvement in oVEMP amplitudes (Pearson correlation -0.472, P = 0.041 and -0.580, P = 0.009, respectively). This study identified clinical, MRI and neurophysiological predictors of recovery in patients with superior VN, and offers additional insight into, and better understanding of, the role of VEMP in diagnosis and prognosis of patients with VN. Further studies are needed to validate this diagnostic procedure and to assess its clinical usefulness in VN management.

  8. Myelin ultrastructure of sciatic nerve in rat experimental autoimmune neuritis model and its correlation with associated protein expression

    PubMed Central

    Yuan, Xiao-Jing; Wei, Yu-Jun; Ao, Qiang; Gong, Kai; Wang, Jian-Yong; Sun, Qiang-San; Zhang, Ling; Zheng, Zun-Cheng; Chen, Lin

    2015-01-01

    To explore the relationship of peripheral nerve ultrastructure and its associated protein expression in experimental autoimmune neuritis (EAN). EAN was established in Lewis rats using an emulsified mixture of P0 peptide 180-199, Mycobacterium tuberculosis, and incomplete Freund’s adjuvant. Rats immunized with saline solution were used as a control group. Sciatic nerve ultrastructure and immunofluorescence histopathology were measured at the neuromuscular severity peak on day 18 post-induction. Cell-specific protein markers were used for immunofluorescence histopathology staining to characterize sciatic nerve cells: CD3 (T cell), Iba-1 (microglia), S100 (myelin), and neurofilament 200 (axon). The results showed that swelling of the myelin lamellae, vesicular disorganization, separation of the myelin lamellae, and an attenuation or disappearance of the axon were observed by transmission electron microscopy in the EAN group. CD3 and Iba-1 increased significantly in the structures characterized by separation or swelling of the myelin lamellae, and increased slightly in the structures characterized by vesicular of the myelin lamellae, S100 decreased in the structures characterized by vesicular disorganization or separation of the myelin lamellae. And neurofilament 200 decreased in the structures characterized by separation of the myelin lamellae. Furthermore, we found that Iba1 were positive in the myelin sheath, and overlapped with S100, which significantly indicated that Schwann cells played as macrophage-like cells during the disease progression of ENA. Our findings may be a significant supplement for the knowledge of EAN model, and may offer a novel sight on the treatment of Guillain-Barré syndrome. PMID:26339349

  9. Damage to the Optic Chiasm in Myelin Oligodendrocyte Glycoprotein–Experimental Autoimmune Encephalomyelitis Mice

    PubMed Central

    Herrera, Sheryl L; Palmer, Vanessa L; Whittaker, Heather; Smith, Blair Cardigan; Kim, Annie; Schellenberg, Angela E; Thiessen, Jonathan D; Buist, Richard; Del Bigio, Marc R; Martin, Melanie

    2014-01-01

    Optic chiasm lesions in myelin oligodendrocyte glycoprotein (MOG)–experimental autoimmune encephalomyelitis (EAE) mice were characterized using magnetic resonance imaging (MRI) and validated using electron microscopy (EM). MR images were collected from 3 days after induction to remission, approximately 20 days after induction. Hematoxylin and eosin, solochrome cyanin–stained sections, and EM images were obtained from the optic chiasms of some mice approximately 4 days after disease onset when their scores were thought to be the highest. T2-weighted imaging and apparent diffusion coefficient map hyperintensities corresponded to abnormalities in the optic chiasms of EAE mice. Mixed inflammation was concentrated at the lateral surface. Degeneration of oligodendrocytes, myelin, and early axonal damage were also apparent. A marked increase in chiasm thickness was observed. T2-weighted and diffusion-weighted MRI can detect abnormalities in the optic chiasms of MOG-EAE mice. MRI is an important method in the study of this model toward understanding optic neuritis. PMID:25520558

  10. Whole-Genome Optical Mapping and Finished Genome Sequence of Sphingobacterium deserti sp. nov., a New Species Isolated from the Western Desert of China

    PubMed Central

    Molnár, István; Li, Xinna; Tang, Ran; Chen, Ming; Wang, Lin; Su, Shiyou; Zhang, Wei; Lin, Min

    2015-01-01

    A novel Gram-negative bacterium, designated ZWT, was isolated from a soil sample of the Western Desert of China, and its phenotypic properties and phylogenetic position were investigated using a polyphasic approach. Growth occurred on TGY medium at 5–42°C with an optimum of 30°C, and at pH 7.0–11.0 with an optimum of pH 9.0. The predominant cellular fatty acids were summed feature 3 (C16:1ω7c/C16:1ω6c or C16:1ω6c/C16:1ω7c) (39.22%), iso-C15:0 (27.91%), iso-C17:0 3OH (15.21%), C16:0 (4.98%), iso-C15:0 3OH (3.03%), C16:0 3OH (5.39%) and C14:0 (1.74%). The major polar lipid of strain ZWT is phosphatidylethanolamine. The only menaquinone observed was MK-7. The GC content of the DNA of strain ZWT is 44.9 mol%. rDNA phylogeny, genome relatedness and chemotaxonomic characteristics all indicate that strain ZWT represents a novel species of the genus Sphingobacterium. We propose the name S. deserti sp. nov., with ZWT (= KCTC 32092T = ACCC 05744T) as the type strain. Whole genome optical mapping and next-generation sequencing was used to derive a finished genome sequence for strain ZWT, consisting of a circular chromosome of 4,615,818 bp in size. The genome of strain ZWT features 3,391 protein-encoding and 48 tRNA-encoding genes. Comparison of the predicted proteome of ZWT with those of other sphingobacteria identified 925 species-unique proteins that may contribute to the adaptation of ZWT to its native, extremely arid and inhospitable environment. As the first finished genome sequence for any Sphingobacterium, our work will serve as a useful reference for subsequent sequencing and mapping efforts for additional strains and species within this genus. PMID:25830331

  11. Are isolated wetlands isolated?

    USGS Publications Warehouse

    Smith, Loren M.; Euliss, Ned H.; Haukos, David A.

    2011-01-01

    While federal regulations during the past 10 years have treated isolated wetlands as unconnected to aquatic resources protected by the Clean Water Act, they provide critical ecosystem services to society that extend well beyond their wetland boundaries. The authors offer well-documented examples from the scientific literature on some of the ecosystem services provided by isolated wetlands to society and other ecosystems.

  12. Optical aberration compensation in a multiplexed optical trapping system

    NASA Astrophysics Data System (ADS)

    Čižmár, T.; Dalgarno, H. I. C.; Ashok, P. C.; Gunn-Moore, F. J.; Dholakia, K.

    2011-04-01

    In this paper we discuss optical aberrations within a multiplexed optical trapping system. We analyze two of the most powerful methods for optical trap multiplexing: time-shared beam steering and holographic beam shaping in a tandem system with an acousto-optic deflector and spatial light modulator. We show how to isolate and correct for the aberrations introduced by these individual optical components using the spatial light modulator and demonstrate the enhancement this provides to optical trapping.

  13. Effect of protein and glycerol concentration on the mechanical, optical, and water vapor barrier properties of canola protein isolate-based edible films.

    PubMed

    Chang, Chang; Nickerson, Michael T

    2015-01-01

    Biodegradable edible films prepared using proteins are both economically and environmentally important to the food packaging industry relative to traditional petroleum-derived synthetic materials. In the present study, the mechanical and water vapor barrier properties of casted canola protein isolate edible films were investigated as a function of protein (5.0% and 7.5%) and glycerol (30%, 35%, 40%, 45%, and 50%) content. Specifically, tensile strength and elongation, elastic modulus, puncture strength and deformation, opacity, and water vapor permeability were measured. Results indicated that tensile strength, puncture strength, and elastic modulus decreased, while tensile elongation and puncture deformation values increased as glycerol concentration increased for both 5.0% and 7.5% canola protein isolate films. Furthermore, tensile strength, puncture strength, and elastic modulus values were found to increase at higher protein concentrations within the canola protein isolate films, whereas puncture deformation values decreased. Tensile elongation was found to be similar for both canola protein isolate protein levels. Canola protein isolate films became more transparent with increasing of glycerol concentration and decreasing of canola protein isolate concentration. Water vapor permeability value was also found to increase with increasing glycerol and protein contents. Overall, results indicated that canola protein isolate films were less brittle, more malleable and transparent, and had greater water vapor permeability at higher glycerol levels. However, as protein level increased, canola protein isolate films were more brittle, less malleable and more opaque, and also had increased water vapor permeability.

  14. A quantitative analysis of gait patterns in vestibular neuritis patients using gyroscope sensor and a continuous walking protocol

    PubMed Central

    2014-01-01

    Background Locomotion involves an integration of vision, proprioception, and vestibular information. The parieto-insular vestibular cortex is known to affect the supra-spinal rhythm generators, and the vestibular system regulates anti-gravity muscle tone of the lower leg in the same side to maintain an upright posture through the extra-pyramidal track. To demonstrate the relationship between locomotion and vestibular function, we evaluated the differences in gait patterns between vestibular neuritis (VN) patients and normal subjects using a gyroscope sensor and long-way walking protocol. Methods Gyroscope sensors were attached to both shanks of healthy controls (n=10) and age-matched VN patients (n = 10). We then asked the participants to walk 88.8 m along a corridor. Through the summation of gait cycle data, we measured gait frequency (Hz), normalized angular velocity (NAV) of each axis for legs, maximum and minimum NAV, up-slope and down-slope of NAV in swing phase, stride-swing-stance time (s), and stance to stride ratio (%). Results The most dominant walking frequency in the VN group was not different compared to normal control. The NAVs of z-axis (pitch motion) were significantly larger than the others (x-, y-axis) and the values in VN patients tended to decrease in both legs and the difference of NAV between both group was significant in the ipsi-lesion side in the VN group only (p=0.03). Additionally, the gait velocity of these individuals was decreased relatively to controls (1.11 ± 0.120 and 0.84 ± 0.061 m/s in control and VN group respectively, p<0.01), which seems to be related to the significantly increased stance and stride time of the ipsi-lesion side. Moreover, in the VN group, the maximum NAV of the lesion side was less, and the minimum one was higher than control group. Furthermore, the down-slope and up-slope of NAV decreased on the impaired side. Conclusion The walking pattern of VN patients was highly phase-dependent, and NAV of pitch motion

  15. [Nonarteritic ischemic optic neuropathy animal model and its treatment applications].

    PubMed

    Chuman, Hideki

    2014-04-01

    Nonarteritic ischemic optic neuropathy (NAION) is one of the most common acute unilaterally onset optic nerve diseases. One management problem in terms of NAION is the difficulty of differential diagnosis between NAION and anterior optic neuritis (ON). A second problem is that there is no established treatment for the acute stage of NAION. A third problem is that there is no preventive treatment for a subsequent attack on the fellow eye, estimated to occur in 15 to 25% of patients with NAION. For differentiation of acute NAION from anterior optic neuritis, we investigated the usefulness of laser speckle flowgraphy (LSFG). In the normal control group, the tissue blood flow did not significantly differ between the right and left eyes. In the NAION group, all 6 patients had 29.5% decreased mean blur rate (MBR), which correlates to optic disc blood flow, of the NAION eye compared with the unaffected eye. In the anterior ON group, all 6 cases had 15.9% increased MBR of the anterior ON eye compared with the unaffected eye. Thus, LSFG showed a difference of the underlying pathophysiology between NAION and anterior ON despite showing disc swelling in both groups and could be useful for differentiating both groups. For the treatment of acute stage of NAION, we tried to reproduce the rodent model of NAION (rNAION) developed by Bernstein and colleagues. To induce rNAION, after the administration of rose bengal(RB) (2.5 mM) into the tail vein of SD rats, the small vessels of the left optic nerve were photoactivated using a 514 nm argon green laser (RB-laser-induction). In the RB-laser-induction eyes, the capillaries within the optic disc were reduced markedly, the optic disc became swollen, and fluorescein angiography showed filling defect in the choroid and the optic disc at an early stage, followed by hyperfluorescence at a late stage. Electrophysiological evaluation revealed that visual evoked potential (VEP) amplitude was significantly decreased but an electroretinogram

  16. A study of retinal parameters measured by optical coherence tomography in patients with multiple sclerosis

    PubMed Central

    Hu, Sai-Jing; You, Yi-An; Zhang, Yi

    2015-01-01

    AIM To investigate the difference of retinal nerve fiber layer (RNFL) thickness and macular fovea thickness/volume between multiple sclerosis (MS) patients and healthy normal individuals using optical coherence tomography (OCT) and assess its association with visual field parameters. METHODS Thirty consecutive MS patients and 28 healthy controls were recruited in this prospective study. Comprehensive standardized ophthalmic examinations included visual acuity, cycloplegic refraction, intraocular pressure, gonioscopy, visual field, and RNFL thickness and macular fovea thickness/volume detection using Humphrey OCT. Mean values for the thickness of the peripapillary RNFL and macular volume were calculated. Associations between visual field parameters and RNFL thickness/macular volume were analyzed by Pearson correlation analysis. RESULTS The RNFL thicknesses in each quadrant, the average macular thickness, and the average macular volume in MS patients were all less than those in healthy controls, with statistically significant differences. The RNFL thickness and macular fovea thickness/volume were greater in eyes without optic neuritis than in eyes with optic neuritis. The average visual field parameters had positive correlations with the RNFL thickness and negative correlations with macular parameters in MS patients. CONCLUSION OCT measurements can effectively identify the nerve changes of MS patients, which provide more data for the diagnosis of MS. PMID:26682175

  17. The Optic Nerve Compartment Syndrome in Cryptococcus-Induced Visual Loss

    PubMed Central

    Moodley, Anand; Naidoo, Neil; Reitz, Deneys; Chetty, Naren; Rae, William

    2013-01-01

    Abstract Visual loss in cryptococcal meningitis has been postulated to be due to papilloedema and/or optic neuritis. A 28-year-old human immunodeficiency virus (HIV)-positive female presented with visual loss, swollen optic discs, and elevated intracranial pressure due to cryptococcal meningitis. Computerised tomographic cisternography and T2-weighted magnetic resonance imaging showed occlusion of the peri-optic subarachnoid space and its reopening after serial lumbar punctures. Presumably lowering of the intracranial pressure resulted in equalisation of pressure across the pressure gradient created by the fungal block. This case supports a third mechanism of visual loss in cryptococcal meningitis, namely, an optic nerve compartment syndrome, that seems more plausible as the principal mechanism. PMID:28163768

  18. The Optic Nerve Compartment Syndrome in Cryptococcus-Induced Visual Loss.

    PubMed

    Moodley, Anand; Naidoo, Neil; Reitz, Deneys; Chetty, Naren; Rae, William

    2013-01-01

    Visual loss in cryptococcal meningitis has been postulated to be due to papilloedema and/or optic neuritis. A 28-year-old human immunodeficiency virus (HIV)-positive female presented with visual loss, swollen optic discs, and elevated intracranial pressure due to cryptococcal meningitis. Computerised tomographic cisternography and T2-weighted magnetic resonance imaging showed occlusion of the peri-optic subarachnoid space and its reopening after serial lumbar punctures. Presumably lowering of the intracranial pressure resulted in equalisation of pressure across the pressure gradient created by the fungal block. This case supports a third mechanism of visual loss in cryptococcal meningitis, namely, an optic nerve compartment syndrome, that seems more plausible as the principal mechanism.

  19. Applications of Optical Coherence Tomography in Pediatric Clinical Neuroscience

    PubMed Central

    Avery, Robert A.; Rajjoub, Raneem D.; Trimboli-Heidler, Carmelina; Waldman, Amy T.

    2015-01-01

    For nearly two centuries, the ophthalmoscope has permitted examination of the retina and optic nerve—the only axons directly visualized by the physician. The retinal ganglion cells project their axons, which travel along the innermost retina to form the optic nerve, marking the beginning of the anterior visual pathway. Both the structure and function of the visual pathway are essential components of the neurologic examination as it can be involved in numerous acquired, congenital and genetic central nervous system conditions. The development of optical coherence tomography now permits the pediatric neuroscientist to visualize and quantify the optic nerve and retinal layers with unprecedented resolution. As optical coherence tomography becomes more accessible and integrated into research and clinical care, the pediatric neuroscientist may have the opportunity to utilize and/or interpret results from this device. This review describes the basic technical features of optical coherence tomography and highlights its potential clinical and research applications in pediatric clinical neuroscience including optic nerve swelling, optic neuritis, tumors of the visual pathway, vigabatrin toxicity, nystagmus, and neurodegenerative conditions. PMID:25803824

  20. Silicon photonics broadband modulation-based isolator.

    PubMed

    Doerr, C R; Chen, L; Vermeulen, D

    2014-02-24

    We discuss an optical isolator design based on tandem phase modulators in a long interferometer. It provides low-loss, broadband isolation in a photonic integrated circuit without requiring special materials or fabrication steps. It was demonstrated in silicon photonics.

  1. Evaluation of a significantly shorter version of the Farnsworth-Munsell 100-hue test in patients with three different optic neuropathies.

    PubMed

    Nichols, B E; Thompson, H S; Stone, E M

    1997-03-01

    We tested the hypothesis that a subset of the Farnsworth-Munsell 100-hue test (FM-100) would be a sensitive, specific, and practical means of monitoring color vision in patients with chronic optic nerve disorders. We retrospectively analyzed the records of 1,113 patients affected with optic neuritis (ON), Graves' ophthalmopathy with suspected optic neuropathy, or idiopathic intracranial hypertension with suspected optic neuropathy (IIH). One hundred six records of patients showed that an FM-100 had been performed (23 ON, 46 Graves', 37 IIH). Forty additional patients were studied prospectively (11 ON, 17 Graves', 12 IIH). The sensitivity and specificity of all possible 21 chip subtests were compared against the same statistics for the entire test. We found that for these three optic nerve disorders, a test consisting of chips 22-42 had nearly the same sensitivity and specificity as the entire test when compared with the clinical diagnosis. At 90% specificity, the ratio of sensitivities of the short version to the original version of the test were IIH, 53%/45%; optic neuritis, 85%/79%; and Graves', 67%/70%. The majority of the clinical value of the test can be achieved in one fourth of the original examination time.

  2. Constructing a statistical atlas of the radii of the optic nerve and cerebrospinal fluid sheath in young healthy adults

    NASA Astrophysics Data System (ADS)

    Harrigan, Robert L.; Plassard, Andrew J.; Mawn, Louise A.; Galloway, Robert L.; Smith, Seth A.; Landman, Bennett A.

    2015-03-01

    Optic neuritis is a sudden inflammation of the optic nerve (ON) and is marked by pain on eye movement, and visual symptoms such as a decrease in visual acuity, color vision, contrast and visual field defects. The ON is closely linked with multiple sclerosis (MS) and patients have a 50% chance of developing MS within 15 years. Recent advances in multi-atlas segmentation methods have omitted volumetric assessment. In the past, measuring the size of the ON has been done by hand. We utilize a new method of automatically segmenting the ON to measure the radii of both the ON and surrounding cerebrospinal fluid (CSF) sheath to develop a normative distribution of healthy young adults. We examine this distribution for any trends and find that ON and CSF sheath radii do not vary between 20-35 years of age and between sexes. We evaluate how six patients suffering from optic neuropathy compare to this distribution of controls. We find that of these six patients, five of them qualitatively differ from the normative distribution which suggests this technique could be used in the future to distinguish between optic neuritis patients and healthy controls

  3. Multiple sclerosis and optic nerve: an analysis of retinal nerve fiber layer thickness and color Doppler imaging parameters

    PubMed Central

    Akçam, H T; Capraz, I Y; Aktas, Z; Batur Caglayan, H Z; Ozhan Oktar, S; Hasanreisoglu, M; Irkec, C

    2014-01-01

    Purpose To compare both retinal nerve fiber layer thickness and orbital color Doppler ultrasonography parameters in patients with multiple sclerosis (MS) versus healthy controls. Methods This is an observational case–control study. Forty eyes from MS patients and twenty eyes from healthy volunteers were examined. Eyes were classified into three groups as group 1, eyes from MS patients with previous optic neuritis (n=20); group 2, eyes from MS patients without previous optic neuritis (n=20); and group 3, eyes from healthy controls (n=20). Following complete ophthalmologic examination and retinal nerve fiber layer thickness measurement for each group, blood flow velocities of posterior ciliary arteries, central retinal artery, ophthalmic artery, and superior ophthalmic vein were measured. Pourcelot index (resistive index), an indicator of peripheral vascular resistance, was also calculated. The statistical assessment was performed with the assistance of Pearson's Chi-square test, Mann–Whitney U-test, Kruskal–Wallis test, and Spearman's correlation test. Results The studied eyes exposed similar values in terms of intraocular pressure and central corneal thickness, implying no evidence in favor of glaucoma. All nerve fiber layer thickness values, except superior nasal quadrants, in group 1 were found to be significantly thinner than groups 2 and 3. Blood flow velocity and mean resistivity index parameters were similar in all the groups. Conclusions In MS patients, especially with previous optic neuritis, diminished retinal nerve fiber layer thickness was observed. Contrary to several studies in the current literature, no evidence supporting potential vascular origin of ocular involvement in MS was found. PMID:25081285

  4. PR-957, a selective inhibitor of immunoproteasome subunit low-MW polypeptide 7, attenuates experimental autoimmune neuritis by suppressing Th17 cell differentiation and regulating cytokine production.

    PubMed

    Liu, Haijie; Wan, Chunxiao; Ding, Yanan; Han, Ranran; He, Yating; Xiao, Jinting; Hao, Junwei

    2017-01-17

    Experimental autoimmune neuritis (EAN) is a CD4(+) T cell-mediated autoimmune inflammatory demyelinating disease of the peripheral nervous system. It has been replicated in an animal model of human inflammatory demyelinating polyradiculoneuropathy, Guillain-Barré syndrome. In this study, we evaluated the therapeutic efficacy of a selective inhibitor of the immunoproteasome subunit, low-MW polypeptide 7 (PR-957) in rats with EAN. Our results showed that PR-957 significantly delayed onset day, reduced severity and shortened duration of EAN, and alleviated demyelination and inflammatory infiltration in sciatic nerves. In addition to significantly regulating expression of the cytokine profile, PR-957 treatment down-regulated the proportion of proinflammatory T helper (Th)17 cells in sciatic nerves and spleens of rats with EAN. Data presented show the role of PR-957 in the signal transducer and activator of transcription 3 (STAT3) pathway. PR-957 not only decreased expression of IL-6 and IL-23 but also led to down-regulation of STAT3 phosphorylation in CD4(+) T cells. Regulation of the STAT3 pathway led to a reduction in retinoid-related orphan nuclear receptor γ t and IL-17 production. Furthermore, reduction of STAT3 phosphorylation may have directly suppressed Th17 cell differentiation. Therefore, our study demonstrates that PR-957 could potently alleviate inflammation in rats with EAN and that it may be a likely candidate for treating Guillain-Barré syndrome.-Liu, H., Wan, C., Ding, Y., Han, R., He, Y., Xiao, J., Hao, J. PR-957, a selective inhibitor of immunoproteasome subunit low-MW polypeptide 7, attenuates experimental autoimmune neuritis by suppressing Th17 cell differentiation and regulating cytokine production.

  5. Broadband Faraday isolator.

    PubMed

    Berent, Michał; Rangelov, Andon A; Vitanov, Nikolay V

    2013-01-01

    Driving on an analogy with the technique of composite pulses in quantum physics, we theoretically propose a broadband Faraday rotator and thus a broadband optical isolator, which is composed of sequences of ordinary Faraday rotators and achromatic quarter-wave plates rotated at the predetermined angles.

  6. Labyrinthitis and Vestibular Neuritis

    MedlinePlus

    ... any further problems. A key component of successful adaptation is a dedicated effort to keep moving, despite ... can prolong or even prevent the process of adaptation. Authors: Charlotte L. Shupert, PhD with contributions from ...

  7. Transparent electrode for optical switch

    DOEpatents

    Goldhar, J.; Henesian, M.A.

    1984-10-19

    The invention relates generally to optical switches and techniques for applying a voltage to an electro-optical crystal, and more particularly, to transparent electodes for an optical switch. System architectures for very large inertial confinement fusion (ICF) lasers require active optical elements with apertures on the order of one meter. Large aperture optical switches are needed for isolation of stages, switch-out from regenerative amplifier cavities and protection from target retroreflections.

  8. Optical Coherence Tomography in Multiple Sclerosis and Neuromyelitis Optica: An Update

    PubMed Central

    Noval, Susana; Contreras, Inés; Muñoz, Silvia; Oreja-Guevara, Celia; Manzano, Beatriz; Rebolleda, Gema

    2011-01-01

    Optical coherence tomography (OCT) uses light interference patterns to produce a cross-sectional image of the retina. It is capable of measuring the unmyelinated axons of the retinal ganglionar cells as they converge on the optic disc. In a disease like multiple sclerosis (MS), in which axonal loss has been identified as an important cause of sustained disability, it may prove an invaluable tool. OCT has demonstrated that axonal loss occurs after each episode of optic neuritis and that the degree of axonal loss is correlated to visual outcomes. Furthermore, axonal loss occurs in MS even in the absence of inflammatory episodes, and the degree of this loss is correlated with the duration of the disease process, with more thinning as the disease advances and in progressive forms. Thus, OCT retinal nerve fiber layer measurements may represent an objective outcome measure with which to evaluate the effect of treatment. PMID:22096638

  9. Investigating Tissue Optical Properties and Texture Descriptors of the Retina in Patients with Multiple Sclerosis

    PubMed Central

    Varga, Boglárka Enikő; Gao, Wei; Laurik, Kornélia Lenke; Tátrai, Erika; Simó, Magdolna; Somfai, Gábor Márk; Cabrera DeBuc, Delia

    2015-01-01

    Purpose To assess the differences in texture descriptors and optical properties of retinal tissue layers in patients with multiple sclerosis (MS) and to evaluate their usefulness in the detection of neurodegenerative changes using optical coherence tomography (OCT) image segmentation. Patients and Methods 38 patients with MS were examined using Stratus OCT. The raw macular OCT data were exported and processed using OCTRIMA software. The enrolled eyes were divided into two groups, based on the presence of optic neuritis (ON) in the history (MSON+ group, n = 36 and MSON- group, n = 31). Data of 29 eyes of 24 healthy subjects (H) were used as controls. A total of seven intraretinal layers were segmented and thickness as well as optical parameters such as contrast, fractal dimension, layer index and total reflectance were measured. Mixed-model ANOVA analysis was used for statistical comparisons. Results Significant thinning of the retinal nerve fiber layer (RNFL), ganglion cell/inner plexiform layer complex (GCL+IPL) and ganglion cell complex (GCC, RNFL+GCL+IPL) was observed between study groups in all comparisons. Significant difference was found in contrast in the RNFL, GCL+IPL, GCC, inner nuclear layer (INL) and outer plexiform layer when comparing MSON+ to the other groups. Higher fractal dimension values were observed in GCL+IPL and INL layers when comparing H vs. MSON+ groups. A significant difference was found in layer index in the RNFL, GCL+IPL and GCC layers in all comparisons. A significant difference was observed in total reflectance in the RNFL, GCL+IPL and GCC layers between the three examination groups. Conclusion Texture and optical properties of the retinal tissue undergo pronounced changes in MS even without optic neuritis. Our results may help to further improve the diagnostic efficacy of OCT in MS and neurodegeneration. PMID:26619298

  10. Optic glioma

    MedlinePlus

    Glioma - optic; Optic nerve glioma; Juvenile pilocytic astrocytoma; Brain cancer - optic glioma ... Optic gliomas are rare. The cause of optic gliomas is unknown. Most optic gliomas are slow-growing ...

  11. Activation of p38 mitogen-activated protein kinase in the early and peak phases of autoimmune neuritis in rat sciatic nerves.

    PubMed

    Moon, Changjong; Ahn, Meejung; Kim, Heechul; Lee, Yongduk; Koh, Chang Sung; Matsumoto, Yoh; Shin, Taekyun

    2005-04-08

    To examine the involvement of p38 mitogen-activated protein kinase (MAPK) in autoimmune disorders of the peripheral nerve system, we analyzed the phosphorylation of p38 MAPK protein in the sciatic nerves of Lewis rats with experimental autoimmune neuritis (EAN). Western blot analysis showed that phosphorylated p38 (p-p38) MAPK protein was significantly increased in the sciatic nerves of rats in the early and peak phases of EAN, and declined gradually thereafter. Immunohistochemistry showed that p-p38 MAPK levels were increased in the infiltrating inflammatory cells, including T cells and macrophages, as well as in blood vessels and some Schwann cells in EAN-affected sciatic nerves, as compared to the sciatic nerves of controls. Some inflammatory cells and a few Schwann cells were also positive for TUNEL reaction at the peak and recovery phases of EAN. In conclusion, we postulate that the phosphorylation of p38 MAPK is involved in the elimination of infiltrating inflammatory cells during the course of EAN and may possibly modulate recovery in autoimmune disorders of the peripheral nervous system.

  12. Effect of Purified Murine NGF on Isolated Photoreceptors of a Rodent Developing Retinitis Pigmentosa

    PubMed Central

    Rocco, Maria Luisa; Balzamino, Bijorn Omar; Petrocchi Passeri, Pamela; Micera, Alessandra; Aloe, Luigi

    2015-01-01

    A number of different studies have shown that neurotrophins, including nerve growth factor (NGF) support the survival of retinal ganglion neurons during a variety if insults. Recently, we have reported that that eye NGF administration can protect also photoreceptor degeneration in a mice and rat with inherited retinitis pigmentosa. However, the evidence that NGF acts directly on photoreceptors and that other retinal cells mediate the NGF effect could not be excluded. In the present study we have isolated retinal cells from rats with inherited retinitis pigmentosa (RP) during the post-natal stage of photoreceptor degenerative. In presence of NGF, these cells are characterized by enhanced expression of NGF-receptors and rhodopsin, the specific marker of photoreceptor and better cell survival, as well as neuritis outgrowth. Together these observations support the hypothesis that NGF that NGF acts directly on photoreceptors survival and prevents photoreceptor degeneration as previously suggested by in vivo studies. PMID:25897972

  13. Production of optically pure L-lactic acid from lignocellulosic hydrolysate by using a newly isolated and D-lactate dehydrogenase gene-deficient Lactobacillus paracasei strain.

    PubMed

    Kuo, Yang-Cheng; Yuan, Shuo-Fu; Wang, Chun-An; Huang, Yin-Jung; Guo, Gia-Luen; Hwang, Wen-Song

    2015-12-01

    The use of lignocellulosic feedstock for lactic acid production with a difficulty is that the release of inhibitory compounds during the pretreatment process which inhibit the growth of microorganism. Thus we report a novel lactic acid bacterium, Lactobacillus paracasei 7 BL, that has a high tolerance to inhibitors and produced optically pure l-lactic acid after the interruption of ldhD gene. The strain 7 BL fermented glucose efficiently and showed high titer of l-lactic acid (215 g/l) by fed-batch strategy. In addition, 99 g/l of l-lactic acid with high yield (0.96 g/g) and productivity (2.25-3.23 g/l/h) was obtained by using non-detoxified wood hydrolysate. Rice straw hydrolysate without detoxification was also tested and yielded a productivity rate as high as 5.27 g/l/h. Therefore, L. paracasei 7 BL represents a potential method of l-lactic acid production from lignocellulosic biomass and has attractive application for industries.

  14. Magneto-optical spaser.

    PubMed

    Baranov, D G; Vinogradov, A P; Lisyansky, A A; Strelniker, Yakov M; Bergman, David J

    2013-06-15

    We present an electrodynamical model of a quantum plasmonic device--the magneto-optical (MO) spaser. It is shown that a spherical gain nanoparticle coated with a metallic MO shell can operate as a spaser amplifying circularly polarized surface plasmons. The MO spaser may be used in design of an optical isolator in plasmonic transmission lines as well as in spaser spectrometry of chiral molecules.

  15. High spatial resolution imaging mass spectrometry of human optic nerve lipids and proteins.

    PubMed

    Anderson, David M G; Spraggins, Jeffrey M; Rose, Kristie L; Schey, Kevin L

    2015-06-01

    The human optic nerve carries signals from the retina to the visual cortex of the brain. Each optic nerve is comprised of approximately one million nerve fibers that are organized into bundles of 800-1200 fibers surrounded by connective tissue and supportive glial cells. Damage to the optic nerve contributes to a number of blinding diseases including: glaucoma, neuromyelitis optica, optic neuritis, and neurofibromatosis; however, the molecular mechanisms of optic nerve damage and death are incompletely understood. Herein we present high spatial resolution MALDI imaging mass spectrometry (IMS) analysis of lipids and proteins to define the molecular anatomy of the human optic nerve. The localization of a number of lipids was observed in discrete anatomical regions corresponding to myelinated and unmyelinated nerve regions as well as to supporting connective tissue, glial cells, and blood vessels. A protein fragment from vimentin, a known intermediate filament marker for astrocytes, was observed surrounding nerved fiber bundles in the lamina cribrosa region. S100B was also found in supporting glial cell regions in the prelaminar region, and the hemoglobin alpha subunit was observed in blood vessel areas. The molecular anatomy of the optic nerve defined by MALDI IMS provides a firm foundation to study biochemical changes in blinding human diseases.

  16. Method for optic nerve intensity characterization in mice from Mn2+ enhanced MR images

    NASA Astrophysics Data System (ADS)

    Xiao, D.; Ribic, J.; Butzkueven, H.; Fang, K.; Kilpatrick, T. J.; Egan, G. F.; Salvado, O.

    2009-02-01

    Investigating whether manganese transport is impaired in the optic nerve of small animal model is a new approach for evaluating optic neuritis. One needs to quantify signal intensity enhancement due to Mn2+ after intra-orbital injection, along the optic nerve from MR images. Quantification is very challenging as the optic nerve (ON) is not straight, its location does not correspond to standard slice orientation, the noise is substantial, and the signal is subject to inhomogeneity from the coil sensitivity. In this paper, we propose a semi-automatic method whereby 1) the retina point and the start of the chiasm in a mouse brain MR image are defined manually in a 3D visualization environment, 2) optic nerve in reformatted slices perpendicular to the optic nerve segment is semi-manually selected, 3) an automatic algorithm extracts the intensities along the optic nerve while correcting for intensity inhomogeneity, and 4) a model for the Mn2+ diffusion with a exponential decay function is fitted to the intensity profile. Results for the study of experimental autoimmune encephalomyelitis (EAE) are reported whereby statistically significant differences were found between the EAE and the control group.

  17. High Spatial Resolution Imaging Mass Spectrometry of Human Optic Nerve Lipids and Proteins

    NASA Astrophysics Data System (ADS)

    Anderson, David M. G.; Spraggins, Jeffrey M.; Rose, Kristie L.; Schey, Kevin L.

    2015-06-01

    The human optic nerve carries signals from the retina to the visual cortex of the brain. Each optic nerve is comprised of approximately one million nerve fibers that are organized into bundles of 800-1200 fibers surrounded by connective tissue and supportive glial cells. Damage to the optic nerve contributes to a number of blinding diseases including: glaucoma, neuromyelitis optica, optic neuritis, and neurofibromatosis; however, the molecular mechanisms of optic nerve damage and death are incompletely understood. Herein we present high spatial resolution MALDI imaging mass spectrometry (IMS) analysis of lipids and proteins to define the molecular anatomy of the human optic nerve. The localization of a number of lipids was observed in discrete anatomical regions corresponding to myelinated and unmyelinated nerve regions as well as to supporting connective tissue, glial cells, and blood vessels. A protein fragment from vimentin, a known intermediate filament marker for astrocytes, was observed surrounding nerved fiber bundles in the lamina cribrosa region. S100B was also found in supporting glial cell regions in the prelaminar region, and the hemoglobin alpha subunit was observed in blood vessel areas. The molecular anatomy of the optic nerve defined by MALDI IMS provides a firm foundation to study biochemical changes in blinding human diseases.

  18. Soluble complement receptor 1 (sCR1) is not as effective as cobra venom factor in the treatment of experimental allergic neuritis.

    PubMed

    Vriesendorp, F J; Flynn, R E; Pappolla, M A; Koski, C L

    1997-12-01

    To further investigate the role of complement activation in Experimental Allergic Neuritis (EAN), the effect of systemic complement blockade by soluble CR1 (sCR1) was compared to complement depletion by Cobra Venom Factor (CVF) in EAN rats immunized with bovine peripheral nerve myelin. EAN rats treated with CVF (n = 10) had significantly reduced clinical scores compared to rats treated with sCR1 (n = 9) or saline (n = 10) (score: sCR1 0.66 +/- 0.7; CVF 0; saline 0.6 +/- 0.8; mean +/- SD). CVF treatment more effectively decreased inflammation and demyelination compared to sCR1 treatment which had only a partial effect (inflammation: sCR1 1.8 +/- 1.4; CVF 0.3 +/- 0.7; saline 1.9 +/- 1.2; demyelination; sCR1 1.3 +/- 1; CVF 0.1 +/- 0.6; saline 1.7 +/- 1.2). In lumbosacral nerve roots significantly less infiltrating ED1 positive macrophages and CD11bc (expressing complement receptor 3 or CR3) positive inflammatory cells were present in CVF treated EAN rats while there was a limited decrease in inflammation in the sCR1 treated animals compared to the saline treated rats (ED1: sCR1 1.4 +/- 1.2; CVF 0.5 +/- 0.6; saline 1.7 +/- 1.2; CD11bc: sCR1 1.9 +/- 1.2; CVF 0.9 +/- 1; saline 2.1 +/- 1.2). Our findings suggest that complement depletion by CVF is more effective than complement blockade by sCR1 in reducing the severity of inflammatory peripheral nerve demyelination.

  19. Reflection beam isolator for submillimeter wavelengths

    NASA Technical Reports Server (NTRS)

    Kanda, M.; May, W. G.

    1974-01-01

    Magnetoplasma reflection beam isolators for submillimeter wave use are discussed. The basic configuration used is that of the Kerr transverse magneto-optical effect. Theoretical and experimental data at 337 microns using InSb as a plasma are given.

  20. Genetics Home Reference: neuromyelitis optica

    MedlinePlus

    ... of the condition. Neuromyelitis optica is characterized by optic neuritis, which is inflammation of the nerve that carries information from the eye to the brain ( optic nerve ). Optic neuritis causes eye pain and vision ...

  1. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  2. High-performance passive viscous isolator element for active/passive (hybrid) isolation

    NASA Astrophysics Data System (ADS)

    Davis, Torey; Davis, L. Porter; Sullivan, Jeanne M.; Hoffman, Terry; Das, Alok

    1996-05-01

    A high performance passive isolator has been developed for a multiaxis isolation system for vibration isolation of an optical payload. This passive isolator will be used along with an active element to provide improved vibration isolation performance over previous isolators. The isolator has been designed using ideas developed previously for 'tuned' three parameter passive isolators. The isolator has also been developed offering the lowest system passive break frequencies structurally feasible for the lightweight optical payload. The implementations of these passive isolator design considerations complement the active portion of the system, and also provide the best passive isolation at the higher frequencies long after the active system has 'rolled off.' The mathematics used to design the isolator as well as the isolator's physical attributes are discussed. The unique design challenges of incorporating the passive element with the active, forming one 'hybrid' D-strut$TM, also are discussed. Finally, actual test data from isolator testing are compared to predicted performance, verifying the isolator's exceptional performance and predictability.

  3. Highly isolated photodetectors

    SciTech Connect

    Bluzer, N.; Borsuk, G.M.; Kub, F.J.; Turley, A.P.

    1984-12-11

    An array of photodetectors is described incorporating a PNP vertical structure in a monosilicon substrate with individual photodetectors optically and electrically isolated from one another by open or oxide filled grooves. Both PN junctions of the PNP structure or originally reverse biased with one junction acting as the photodetector may operate in the forward biased photovoltaic mode with high radiant energy intensity. The minority carriers injected into the N region are absorbed by the other PN junction providing base-collector transistor action to prevent blooming.

  4. Power supply with optical-isolator control

    NASA Technical Reports Server (NTRS)

    Baker, R. H.; Wheeler, J. T.

    1977-01-01

    Power supply consists of several stages, interconnected and programmed for required output. In capacitor charging mode, transistor switches are closed. Last stage is in series with rectifier that prevents current from flowing backward into circuit. In capacitor discharge mode, transistor switches are closed, and voltage delivered to load is sum of voltages across capacitors.

  5. High-power Faraday isolators based on TAG ceramics.

    PubMed

    Zheleznov, Dmitry; Starobor, Aleksey; Palashov, Oleg; Chen, Chong; Zhou, Shengming

    2014-02-10

    The Faraday isolator based on a new magneto-optical medium--TAG (terbium aluminum garnet) ceramics was implemented and investigated experimentally. The magneto-optical element was temperature-stabilized using water cooling. The device provides a stable isolation ratio of 38 dB at 300 W laser power. Estimates show high performance of the device at a kilowatt laser power.

  6. Analyses on the misdiagnoses of 25 patients with unilateral optic nerve sheath meningioma

    PubMed Central

    Mao, Jun-Feng; Xia, Xiao-Bo; Tang, Xiang-Bo; Zhang, Xue-Yong; Wen, Dan

    2016-01-01

    AIM To investigate clinical features of optic nerve sheath meningioma (ONSM) that was misdiagnosed, and to find methods to reduce the misdiagnoses. METHODS Retrospective series study. Twenty-five misdisgnosed patients with unilateral ONSM were collected from Jan. 2008 to Jan. 2015 and the clinical records reviewed. RESULTS Patients were misdiagnosed with acute papillitis most frequently (n=17), immediately followed by optic atrophy (n=8), ischemic optic neuropathy (n=5), acute retrobulbar optic neuritis (n=5), optic disc vasculitis (n=3). For each patient, the minimum frequency of misdiagnoses was once and the maximum was 4 times. As for the lasting time of being misdiagnosed, the shortest was 1.5mo and the longest was 45mo. Twenty-one cases (84%) were once treated with glucocorticoids, and its side effects was found in seventeen patients. Twenty patients (80%) complained with varying degree of vision loss. When a definite diagnosis was made, sixteen cases (64%) showed slight exophthalmos and eighteen cases (72%) had the tubular ONSM. CONCLUSION ONSM without loss obvious exophthalmos is easily misdiagnosed in clinic, and for most of these ONSMs are tubular. PMID:27672598

  7. Optical source and apparatus for remote sensing

    NASA Technical Reports Server (NTRS)

    Coyle, Donald Barry (Inventor)

    2011-01-01

    An optical amplifier is configured to amplify an injected seed optical pulse. The optical amplifier may include two or more gain sections coupled to form a continuous solid waveguide along a primary optical path. Each gain section may include: (i) an optical isolator forming an input to that gain section; (ii) a doped optical fiber having a first end coupled to the optical isolator and having a second end; (iii) a plurality of pump laser diodes; (iv) a controller providing drive signals to each of the plurality, the controller being configured to provide at least pulsed drive signals; and (v) an optical coupler having a first input port coupled to the second end, and a second input port coupled to the plurality and an output port.

  8. Cranial neuropathy, myeloradiculopathy, and myositis: complications of Mycoplasma pneumoniae infection.

    PubMed

    Rothstein, T L; Kenny, G E

    1979-08-01

    Polymyositis, transverse myelitis, ascending polyneuritis, bilateral optic neuritis, and hearing loss developed in a patient with high complement-fixing antibody titers to Mycoplasma pneumoniae. Each of her three children had primary atypical pneumonia with isolation of the organism. The neurologic disturbance is thought to represent a postinfectious complication of M pneumoniae infection.

  9. Faraday isolator based on TSAG crystal for high power lasers.

    PubMed

    Mironov, E A; Palashov, O V

    2014-09-22

    A Faraday isolator based on a new magneto-optical medium, TSAG (terbium scandium aluminum garnet) crystal, has been constructed and investigated experimentally. The device provides an isolation ratio of more than 30 dB at 500 W laser power. It is shown that this medium can be used in Faraday isolators for kilowatt-level laser powers.

  10. Evaluation of the BioVigilant IMD-A, a novel optical spectroscopy technology for the continuous and real-time environmental monitoring of viable and nonviable particles. Part II. Case studies in environmental monitoring during aseptic filling, intervention assessments, and glove integrity testing in manufacturing isolators.

    PubMed

    Miller, Michael J; Walsh, Michael R; Shrake, Jerry L; Dukes, Randall E; Hill, Daniel B

    2009-01-01

    This paper describes the use of the BioVigilant IMD-A, a real-time and continuous monitoring technology based on optical spectroscopy, to simultaneously and instantaneously detect, size, and enumerate both viable and nonviable particles in a variety of filling and transfer isolator environments during an aseptic fill, transfer of sterilized components, and filling interventions. Continuous monitoring of three separate isolators for more than 16 h and representing more than 28 m3 of air per isolator (under static conditions) yielded a mean viable particle count of zero (0) per cubic meter. Although the mean count per cubic meter was zero, the detection of very low levels of single viable particles was randomly observed in each of these sampling runs. No viable particles were detected during the manual transfer of sterilized components from transfer isolators into a filling isolator, and similar results were observed during an aseptic fill, a filling needle change-out procedure, and during disassembly, movement, and reassembly of a vibrating stopper bowl. During the continuous monitoring of a sample transfer port and a simulated mousehole, no viable particles were detected; however, when the sampling probe was inserted beyond the isolator-room interface, the IMD-A instantaneously detected and enumerated both viable and nonviable particles originating from the surrounding room. Data from glove pinhole studies showed no viable particles being observed, although significant viable particles were immediately detected when the gloves were removed and a bare hand was allowed to introduce microorganisms into the isolator. The IMD-A technology offers the industry an unprecedented advantage over growth-based bioaerosol samplers for monitoring the state of microbiological control in pharmaceutical manufacturing environments, and represents significant progress toward the acceptance of microbiology process analytical technology solutions for the industry.

  11. [Optic disc granuloma secondary to sarcoidosis].

    PubMed

    Qu-Knafo, L; Auregan-Giocanti, A

    2017-02-01

    We report a case of optic disc granuloma due to sarcoidosis. A 64-year-old, caucasian female with a history of pulmonary sarcoidosis presented with a vision loss on her left eye. The ophthalmologic examination revealed a discrete optic disc infiltrate compatible with the diagnosis of optic disc granuloma. Fluorescein angiography showed diffusion and impregnation of the granuloma without vascularitis. The optical coherence tomography demonstrated a homogenous and isoreflective lesion at the optic disc. The patient recovered her visual acuity after systemic corticosteroid treatment. Isolated optic disc granuloma is a rare condition of ocular sarcoidosis.

  12. Permanent-magnet Faraday isolator with the field intensity of 25 kOe

    SciTech Connect

    Mironov, E A; Snetkov, I L; Voitovich, A V; Palashov, O V

    2013-08-31

    A Faraday isolator with a single magneto-optical element is constructed and experimentally tested. It provides the isolation ratio of 30 dB at an average laser radiation power of 650 W. These parameters are obtained by increasing the field intensity in the magnetic system of the isolator and employing a low-absorption magneto-optical element. (elements of laser devices)

  13. Optical microspectrometer

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2004-05-25

    An optical microspectrometer comprises a grism to disperse the spectra in a line object. A single optical microspectrometer can be used to sequentially scan a planar object, such as a dye-tagged microchip. Because the optical microspectrometer is very compact, multiple optical microspectrometers can be arrayed to provide simultaneous readout across the width of the planar object The optical microspectrometer can be fabricated with lithographic process, such as deep X-ray lithography (DXRL), with as few as two perpendicular exposures.

  14. Optically tunable optical filter

    NASA Astrophysics Data System (ADS)

    James, Robert T. B.; Wah, Christopher; Iizuka, Keigo; Shimotahira, Hiroshi

    1995-12-01

    We experimentally demonstrate an optically tunable optical filter that uses photorefractive barium titanate. With our filter we implement a spectrum analyzer at 632.8 nm with a resolution of 1.2 nm. We simulate a wavelength-division multiplexing system by separating two semiconductor laser diodes, at 1560 nm and 1578 nm, with the same filter. The filter has a bandwidth of 6.9 nm. We also use the same filter to take 2.5-nm-wide slices out of a 20-nm-wide superluminescent diode centered at 840 nm. As a result, we experimentally demonstrate a phenomenal tuning range from 632.8 to 1578 nm with a single filtering device.

  15. GOES-R Dual Isolation

    NASA Technical Reports Server (NTRS)

    Freesland, Doug; Carter, Delano; Chapel, Jim; Clapp, Brian; Howat, John; Krimchansky, Alexander

    2015-01-01

    The Geostationary Operational Environmental Satellite-R Series (GOES-R) is the first of the next generation geostationary weather satellites, scheduled for delivery in late 2015. GOES-R represents a quantum increase in Earth and solar weather observation capabilities, with 4 times the resolution, 5 times the observation rate, and 3 times the number of spectral bands for Earth observations. With the improved resolution, comes the instrument suite's increased sensitive to disturbances over a broad spectrum 0-512 Hz. Sources of disturbance include reaction wheels, thruster firings for station keeping and momentum management, gimbal motion, and internal instrument disturbances. To minimize the impact of these disturbances, the baseline design includes an Earth Pointed Platform (EPP), a stiff optical bench to which the two nadir pointed instruments are collocated together with the Guidance Navigation & Control (GN&C) star trackers and Inertial Measurement Units (IMUs). The EPP is passively isolated from the spacecraft bus with Honeywell D-Strut isolators providing attenuation for frequencies above approximately 5 Hz in all six degrees-of-freedom. A change in Reaction Wheel Assembly (RWA) vendors occurred very late in the program. To reduce the risk of RWA disturbances impacting performance, a secondary passive isolation system manufactured by Moog CSA Engineering was incorporated under each of the six 160 Nms RWAs, tuned to provide attenuation at frequencies above approximately 50 Hz. Integrated wheel and isolator testing was performed on a Kistler table at NASA Goddard Space Flight Center. High fidelity simulations were conducted to evaluate jitter performance for four topologies: 1) hard mounted no isolation, 2) EPP isolation only, 2) RWA isolation only, and 4) dual isolation. Simulation results demonstrate excellent performance relative to the pointing stability requirements, with dual isolated Line of Sight (LOS) jitter less than 1 micron rad.

  16. Optical and infrared masers

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Ongoing research progress in the following areas is described: (1) tunable infrared light sources and applications; (2) precision frequency and wavelength measurements in the infrared with applications to atomic clocks; (3) zero-degree pulse propagation in resonant medium; (4) observation of Dicke superradiance in optically pumped HF gas; (5) unidirectional laser amplifier with built-in isolator; and (6) progress in infrared metal-to-metal point contact tunneling diodes.

  17. Nanophotonics of isolated spherical particles

    NASA Astrophysics Data System (ADS)

    Geints, Yu. É.; Zemlyanov, A. A.; Panina, E. K.

    2010-09-01

    The problem of extreme focusing of an optical beam into the spatial region with wavelength dimensions is considered with the use of the special features of radiation interaction with isolated spherical particles. Results of numerical computations of the optical field intensity at the surface of silver particles of different radii upon exposure to laser radiation with different wavelengths are presented. It is demonstrated that the relative intensity of the plasmon optical field on the nanoparticle surface increases and the field focusing region decreases with increasing particle radius. Results of numerical computations illustrating the influence of the shell of composite nanoparticles comprising a dielectric core and a metal shell on the optical field intensity in the vicinity of the particle are presented. The problem of local optical foci of a transparent microparticle (photonic nanojets) is investigated. It is established that variation of the micron particle size, its optical properties, and laser radiation parameters allows the amplitude and spatial characteristics of the photonic nanojet region to be controlled efficiently.

  18. High speed optical networks

    NASA Astrophysics Data System (ADS)

    Frankel, Michael Y.; Livas, Jeff

    2005-02-01

    unregenerated reach. More sophisticated optical amplifiers provide lower noise for increased reach and increased spectral bandwidth for higher wavelength count lower wavelength blocking probability. Optical analog networks also require methods for mitigating optical power transients, for controlling optical spectral flatness, and for dynamically managing changes (e.g. in chromatic dispersion and polarization mode dispersion.) Since signals stay in the optical domain, optical performance monitoring techniques are required for fault isolation and correction. Efficient routing of optical signals also requires sophisticated switching nodes with an ability to selectively steer optical signals into several directions with single-channel spectral granularity. Most of these technologies are not modular and require interruption of service if not deployed at the initial system installation, thereby increasing first install costs substantially, even if initial capacity loading is small. Further, validation of systems and software targeting a specific network design is complex. Only a small fraction of the total network may be reasonably reproduced in the lab, and many field configurations are not predictable or even dynamic. Thus, extra system margin has to be allocated to handle the behavior uncertainty. To constrain the complexity of both hardware technology and software algorithms, regions of network transparency can be established with OEO forced at perimeters. Thus, "analog" regions are surrounded by "digital" interfaces. Following are some example tradeoffs that will be discussed. What is a good modulation format choice, and does increased reach and impairment resiliency justify hardware and controls that are more complicated? What are reasonable amplifier choices to make under specific network assumptions? Can high transport system capacity be leveraged to simplify optical switch node design by reducing spectral efficiency?

  19. Eight electrode optical readout gap

    DOEpatents

    Boettcher, Gordon E.; Crain, Robert W.

    1985-01-01

    A protective device for a plurality of electrical circuits includes a pluity of isolated electrodes forming a gap with a common electrode. An output signal, electrically isolated from the circuits being monitored, is obtained by a photosensor viewing the discharge gap through an optical window. Radioactive stabilization of discharge characteristics is provided for slowly changing voltages and carbon tipped dynamic starters provide desirable discharge characteristics for rapidly varying voltages. A hydrogen permeation barrier is provided on external surfaces of the device.

  20. In-vacuum Faraday isolation remote tuning.

    PubMed

    Accadia, T; Acernese, F; Antonucci, F; Aoudia, S; Arun, K G; Astone, P; Ballardin, G; Barone, F; Barsuglia, M; Bauer, Th S; Beker, M G; Bigotta, S; Birindelli, S; Bitossi, M; Bizouard, M A; Blom, M; Boccara, C; Bondu, F; Bonelli, L; Bosi, L; Braccini, S; Bradaschia, C; Brillet, A; Brisson; Budzynski, R; Bulik, T; Bulten, H J; Buskulic, D; Cagnoli, G; Calloni, E; Campagna, E; Canuel, B; Carbognani, F; Cavalier, F; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chincarini, A; Cleva, F; Coccia, E; Colacino, C N; Colas, J; Colla, A; Colombini, M; Corda, C; Corsi, A; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; Day, R; De Rosa, R; del Prete, M; Di Fiore, L; Di Lieto, A; Emilio, M Di Paolo; Di Virgilio, A; Dietz, A; Drago, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Franc, J; Frasca, S; Frasconi, F; Freise, A; Gammaitoni, L; Garufi, F; Gemme, G; Genin, E; Gennai, A; Giazotto, A; Gouaty, R; Granata, M; Greverie, C; Guidi, G M; Heitmann, H; Hello, P; Hild, S; Huet, D; Jaranowski, P; Kowalska, I; Królak, A; La Penna, P; Leroy, N; Letendre, N; Li, T G F; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Michel, C; Milano, L; Minenkov, Y; Mohan, M; Moreau, J; Morgado, N; Morgia, A; Mosca, S; Moscatelli, V; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palladino, L; Palomba, C; Paoletti, F; Pardi, S; Parisi, M; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Pichot, M; Piergiovanni, F; Pietka, M; Pinard, L; Poggiani, R; Prato, M; Prodi, G A; Punturo, M; Puppo, P; Rabaste, O; Rabeling, D S; Rapagnani, P; Re, V; Regimbau, T; Ricci, F; Robinet, F; Rocchi, A; Rolland, L; Romano, R; Rosińska, D; Ruggi, P; Sassolas, B; Sentenac, D; Sturani, R; Swinkels, B; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Trummer, J; Vajentei, G; van den Brand, J F J; van der Putten, S; Vavoulidis, M; Vedovato, G; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Was, M; Yvert, M

    2010-09-01

    In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air.

  1. Optical Solitons

    NASA Astrophysics Data System (ADS)

    Taylor, J. R.

    2005-08-01

    1. Optical solitons in fibres: theoretical review A. Hasegawa; 2. Solitons in optical fibres: an experimental account L. F. Mollenauer; 3. All-optical long-distance soliton-based transmission systems K. Smith and L. F. Mollenauer; 4. Nonlinear propagation effects in optical fibres: numerical studies K. J. Blow and N. J. Doran; 5. Soliton-soliton interactions C. Desem and P. L. Chu; 6. Soliton amplification in erbium-doped fibre amplifiers and its application to soliton communication M. Nakazawa; 7. Nonlinear transformation of laser radiation and generation of Raman solitons in optical fibres E. M. Dianov, A. B. Grudinin, A. M. Prokhorov and V. N. Serkin; 8. Generation and compression of femtosecond solitons in optical fibers P. V. Mamyshev; 9. Optical fibre solitons in the presence of higher order dispersion and birefringence C. R. Menyuk and Ping-Kong A. Wai; 10. Dark optical solitons A. M. Weiner; 11. Soliton Raman effects J. R. Taylor; Bibliography; Index.

  2. Optical Solitons

    NASA Astrophysics Data System (ADS)

    Taylor, J. R.

    1992-04-01

    1. Optical solitons in fibres: theoretical review A. Hasegawa; 2. Solitons in optical fibres: an experimental account L. F. Mollenauer; 3. All-optical long-distance soliton-based transmission systems K. Smith and L. F. Mollenauer; 4. Nonlinear propagation effects in optical fibres: numerical studies K. J. Blow and N. J. Doran; 5. Soliton-soliton interactions C. Desem and P. L. Chu; 6. Soliton amplification in erbium-doped fibre amplifiers and its application to soliton communication M. Nakazawa; 7. Nonlinear transformation of laser radiation and generation of Raman solitons in optical fibres E. M. Dianov, A. B. Grudinin, A. M. Prokhorov and V. N. Serkin; 8. Generation and compression of femtosecond solitons in optical fibers P. V. Mamyshev; 9. Optical fibre solitons in the presence of higher order dispersion and birefringence C. R. Menyuk and Ping-Kong A. Wai; 10. Dark optical solitons A. M. Weiner; 11. Soliton Raman effects J. R. Taylor; Bibliography; Index.

  3. Optical probe

    DOEpatents

    Hencken, Kenneth; Flower, William L.

    1999-01-01

    A compact optical probe is disclosed particularly useful for analysis of emissions in industrial environments. The instant invention provides a geometry for optically-based measurements that allows all optical components (source, detector, rely optics, etc.) to be located in proximity to one another. The geometry of the probe disclosed herein provides a means for making optical measurements in environments where it is difficult and/or expensive to gain access to the vicinity of a flow stream to be measured. Significantly, the lens geometry of the optical probe allows the analysis location within a flow stream being monitored to be moved while maintaining optical alignment of all components even when the optical probe is focused on a plurality of different analysis points within the flow stream.

  4. Mechanical strain isolator mount

    NASA Technical Reports Server (NTRS)

    James, Gordon E. (Inventor)

    1991-01-01

    Certain devices such as optical instruments must preserve their alignmental integrity while being subjected to mechanical strain. A mechanical strain isolator mount is provided to preserve the alignmental integrity of an alignment sensitive instrument. An alignment sensitive instrument is mounted on a rectangular base. Flexural legs are connected at their proximal ends to the rectangular base. Flexural legs are also spaced parallel to the sides. Mounting pads are connected to the legs at the distal end and the mechanical strain isolator mount is attached to the substrate by means of threaded bolts. When a mounting pad and its respective leg is subjected to lateral strain in either the X or Y direction via the substrate, the respective leg relieves the strain by bending in the direction of the strain. An axial strain on a mounting pad in the Z direction is relieved by a rotational motion of the legs in the direction of the strain. When the substrate is stress free, the flexural legs return to their original condition and thus preserve the original alignment integrity of the alignment sensitive instrument.

  5. Microprecision interferometer: evaluation of new disturbance isolation solutions

    NASA Astrophysics Data System (ADS)

    O'Brien, John F.; Goullioud, Renaud; Neat, Gregory W.

    1998-06-01

    This paper describes a benchmark to assess performance of six- axis vibration isolation systems. The targeted application, spaceborne interferometers, require isolation of the reaction wheel disturbances in order to stabilize the precision optical elements to the required levels. The problem is to isolate this vibrating payload from the quiet structure (spacecraft). The unique feature of this procedure is that isolator performance is measured in terms of the stability of the interferometer optical elements. Central to the procedure is the Micro-Precision Interferometer (MPI) testbed which is a hardware model of a future spaceborne optical interferometer. The isolation system under evaluation is mounted on the testbed and disturbance transfer functions are then measured from the isolator payload to the optical sensor output that must be stabilized. Off-line, the procedure combines these measured testbed transfer functions with an empirical model of the reaction wheel disturbance, in order predict isolator performance over the entire range of wheel speeds. The paper applies the procedure to four different disturbance interface conditions: hard mounted, passive hexapod isolator, active hexapod isolator and a passive elastomeric isolator. The paper contains all the necessary information to allow industry, academia or other organizations to evaluate custom designs in this testbed facility.

  6. Optical keyboard

    DOEpatents

    Veligdan, James T.; Feichtner, John D.; Phillips, Thomas E.

    2001-01-01

    An optical keyboard includes an optical panel having optical waveguides stacked together. First ends of the waveguides define an inlet face, and opposite ends thereof define a screen. A projector transmits a light beam outbound through the waveguides for display on the screen as a keyboard image. A light sensor is optically aligned with the inlet face for sensing an inbound light beam channeled through the waveguides from the screen upon covering one key of the keyboard image.

  7. Development of variable-damping isolator using bio-metal fiber for reaction wheel vibration isolation

    NASA Astrophysics Data System (ADS)

    Oh, Hyun-Ung; Izawa, Katsuhiko; Taniwaki, Shigemune

    2005-10-01

    This study focuses on the basic characteristics of a variable-damping isolator using a bio-metal fiber (BMF) valve to enhance the pointing performance of optical equipment on-board satellites. A variable-damping BMF valve isolator for isolating disturbances induced by reaction-wheel operation has been designed and fabricated. The opening and closing of the valve to change the damping of the isolator is implemented by using characteristic variation of the bio-metal fiber to the input electric current. The BMF isolator fabricated in this study has the advantages of being a simple variable-damping device with low power consumption, unlike conventional variable-damping devices, such as solenoid-valve-type oil dampers and ER or MR dampers. This paper presents the basic characteristics of the BMF isolator obtained from dynamic tests of the isolator.

  8. Polarization proximity effect in isolator crystal pairs.

    PubMed

    Linzon, Y; Ferrera, M; Razzari, L; Pignolet, A; Morandotti, R

    2008-12-01

    We experimentally study the polarization dynamics (orientation and ellipticity) of near-infrared light transmitted through magneto-optical yttrium iron garnet isolator crystal pairs using a modified balanced detection scheme. When the pair separation is in the submillimeter range, we observed a proximity effect in which the saturation field is reduced by up to 20%. One-dimensional calculations suggest that the proximity effect originates from magnetostatic interactions between the dipole moments of the isolator crystals.

  9. Interferometric optical vortex array generator

    SciTech Connect

    Vyas, Sunil; Senthilkumaran, P

    2007-05-20

    Two new interferometric configurations for optical vortex array generation are presented.These interferometers are different from the conventional interferometers in that they are capable of producing a large number of isolated zeros of intensity, and all of them contain optical vortices. Simulation and theory for optical vortex array generation using three-plane-wave interference is presented. The vortex dipole array produced this way is noninteracting, as there are no attraction or repulsion forces between them, leading to annihilation or creation of vortex pairs.

  10. Optical Micromachining

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Under an SBIR (Small Business Innovative Research) with Marshall Space Flight Center, Potomac Photonics, Inc., constructed and demonstrated a unique tool that fills a need in the area of diffractive and refractive micro-optics. It is an integrated computer-aided design and computer-aided micro-machining workstation that will extend the benefits of diffractive and micro-optic technology to optical designers. Applications of diffractive optics include sensors and monitoring equipment, analytical instruments, and fiber optic distribution and communication. The company has been making diffractive elements with the system as a commercial service for the last year.

  11. Fluidic optics

    NASA Astrophysics Data System (ADS)

    Whitesides, George M.; Tang, Sindy K. Y.

    2006-09-01

    Fluidic optics is a new class of optical system with real-time tunability and reconfigurability enabled by the introduction of fluidic components into the optical path. We describe the design, fabrication, operation of a number of fluidic optical systems, and focus on three devices, liquid-core/liquid-cladding (L2) waveguides, microfluidic dye lasers, and diffraction gratings based on flowing, crystalline lattices of bubbles, to demonstrate the integration of microfluidics and optics. We fabricate these devices in poly(dimethylsiloxane) (PDMS) with soft-lithographic techniques. They are simple to construct, and readily integrable with microanalytical or lab-on-a-chip systems.

  12. Optic Nerve Lymphoma. Report of Two Cases and Review of the Literature

    PubMed Central

    Kim, Jennifer L.; Mendoza, Pia; Rashid, Alia; Hayek, Brent; Grossniklaus, Hans E.

    2014-01-01

    Lymphoma may involve the optic nerve as isolated optic nerve lymphoma or in association with CNS or systemic lymphoma. We present two biopsy-proven non-Hodgkin lymphomas of the optic nerve and compare our findings with previously reported cases. We discuss the mechanism of metastasis, classification of optic nerve involvement, clinical features, radiologic findings, optic nerve biopsy indications and techniques, histologic features, and treatments. We propose a classification system of optic nerve lymphoma: isolated optic nerve involvement, optic nerve involvement with CNS disease, optic nerve involvement with systemic disease, and optic nerve involvement with primary intraocular lymphoma. Although it is an uncommon cause of infiltrative optic neuropathy, optic nerve metastasis should be considered in patients with a history of lymphoma. The recommended approach to a patient with presumed optic nerve lymphoma includes neuroimaging, and cerebrospinal fluid evaluation as part of the initial work-up, then judicious use of optic nerve biopsy, depending on the clinical situation. PMID:25595061

  13. Detection of retinal blood vessel changes in multiple sclerosis with optical coherence tomography

    PubMed Central

    Bhaduri, Basanta; Nolan, Ryan M.; Shelton, Ryan L.; Pilutti, Lara A.; Motl, Robert W.; Moss, Heather E.; Pula, John H.; Boppart, Stephen A.

    2016-01-01

    Although retinal vasculitis is common in multiple sclerosis (MS), it is not known if MS is associated with quantitative abnormalities in retinal blood vessels (BVs). Optical coherence tomography (OCT) is suitable for examining the integrity of the anterior visual pathways in MS. In this paper we have compared the size and number of retinal blood vessels in patients with MS, with and without a history of optic neuritis (ON), and control subjects from the cross-sectional retinal images from OCT. Blood vessel diameter (BVD), blood vessel number (BVN), and retinal nerve fiber layer thickness (RNFLT) were extracted from OCT images collected from around the optic nerves of 129 eyes (24 control, 24 MS + ON, 81 MS-ON) of 71 subjects. Associations between blood vessel metrics, MS diagnosis, MS disability, ON, and RNFLT were evaluated using generalized estimating equation (GEE) models. MS eyes had a lower total BVD and BVN than control eyes. The effect was more pronounced with increased MS disability, and persisted in multivariate models adjusting for RNFLT and ON history. Twenty-nine percent (29%) of MS subjects had fewer retinal blood vessels than all control subjects. MS diagnosis, disability, and ON history were not associated with average blood vessel size. The relationship between MS and lower total BVD/BVN is not accounted for by RNFLT or ON. Further study is needed to determine the relationship between OCT blood vessel metrics and qualitative retinal blood vessel abnormalities in MS. PMID:27375947

  14. Sera from patients with seropositive neuromyelitis optica spectral disorders caused the degeneration of rodent optic nerve.

    PubMed

    Matsumoto, Yoshiko; Kanamori, Akiyasu; Nakamura, Makoto; Takahashi, Toshiyuki; Nakashima, Ichiro; Negi, Akira

    2014-02-01

    Neuromyelitis optica (NMO) is an autoimmune inflammatory, neurodestructive disease primarily targeting the optic nerve and spinal cord. An autoantibody against water channel protein aquaporin-4 (AQP4), which is expressed at endofeet of astrocytes has been implicated in the pathogenesis of NMO. We evaluated the impact of sera of seropositive patients with NMO spectrum disorders (NMOSDs) on the rodent optic nerve and retina. Serum was obtained either from patients with seropositive NMOSD (AQP4+), seronegative patient with idiopathic optic neuritis (AQP4-), and healthy volunteers (control). Anti-AQP4 antibody in a serum was measured by a previously established cell-based assay. The patients' sera were applied on the optic nerve after de-sheathed. Immunohistochemistry showed that at 7 days after the treatment, the area of the optic nerve exposed to the AQP4+ sera lost expression of both AQP4 and glial fibrillary acidic protein. Also, Human-IgG immunoreactivity and marked invasion of inflammation cells were observed in the optic nerve treated with AQP4+ serum. Immnoreactivity of neurofilament was reduced at 14 days after the treatment, not 7 days. Real-time polymerase chain reaction revealed the reduced gene expression of neurofilament in retina from the eye that was exposed to the AQP4+ sera at 14 days. Retrograde fluorogold-labeling on the retinal flatmount disclosed the significantly reduced number of retinal ganglion cells when the AQP4+ sera were applied. The present model has demonstrated that the sera from patients with seropositive NMOSDs led to the regional astrocytic degeneration and inflammatory cell invasion in the optic nerve, resulting in the ultimate loss of RGCs and their axons at areas beyond the injury site.

  15. Optical key system

    DOEpatents

    Hagans, Karla G.; Clough, Robert E.

    2000-01-01

    An optical key system comprises a battery-operated optical key and an isolated lock that derives both its operating power and unlock signals from the correct optical key. A light emitting diode or laser diode is included within the optical key and is connected to transmit a bit-serial password. The key user physically enters either the code-to-transmit directly, or an index to a pseudorandom number code, in the key. Such person identification numbers can be retained permanently, or ephemeral. When a send button is pressed, the key transmits a beam of light modulated with the password information. The modulated beam of light is received by a corresponding optical lock with a photovoltaic cell that produces enough power from the beam of light to operate a password-screen digital logic. In one application, an acceptable password allows a two watt power laser diode to pump ignition and timing information over a fiberoptic cable into a sealed engine compartment. The receipt of a good password allows the fuel pump, spark, and starter systems to each operate. Therefore, bypassing the lock mechanism as is now routine with automobile thieves is pointless because the engine is so thoroughly disabled.

  16. Optical key system

    SciTech Connect

    Hagans, K.G.; Clough, R.E.

    2000-04-25

    An optical key system comprises a battery-operated optical key and an isolated lock that derives both its operating power and unlock signals from the correct optical key. A light emitting diode or laser diode is included within the optical key and is connected to transmit a bit-serial password. The key user physically enters either the code-to-transmit directly, or an index to a pseudorandom number code, in the key. Such person identification numbers can be retained permanently, or ephemeral. When a send button is pressed, the key transmits a beam of light modulated with the password information. The modulated beam of light is received by a corresponding optical lock with a photovoltaic cell that produces enough power from the beam of light to operate a password-screen digital logic. In one application, an acceptable password allows a two watt power laser diode to pump ignition and timing information over a fiberoptic cable into a sealed engine compartment. The receipt of a good password allows the fuel pump, spark, and starter systems to each operate. Therefore, bypassing the lock mechanism as is now routine with automobile thieves is pointless because the engine is so thoroughly disabled.

  17. Dynamic Rheooptical Behavior of Isolated Bovine Cornea

    PubMed Central

    Kaplan, Donald; Bettelheim, Frederick A.

    1972-01-01

    The dynamic Young's modulus E′ and loss modulus E″ were obtained for isolated bovine cornea using a direct-reading dynamic viscoelastometer. Within the temperature range (0-60°C) and frequency range (3.5-110 Hz) studied, both moduli were temperature and frequency independent. The dynamic birefringence of the cornea was measured in a special apparatus designed for this purpose in conjunction with the dynamic viscoelastometer. The stress-optical and strain-optical coefficients as well as the corresponding phase angles were evaluated as a function of temperature and frequency. The strain- and stress-optical coefficients were both temperature and frequency dependent. PMID:4655663

  18. Optical communication components

    NASA Astrophysics Data System (ADS)

    Eldada, Louay

    2004-03-01

    We review and contrast key technologies developed to address the optical components market for communication applications. We first review the component requirements from a network perspective. We then look at different material systems, compare their properties, and describe the functions achieved to date in each of them. The material systems reviewed include silica fiber, silica on silicon, silicon on insulator, silicon oxynitride, sol-gels, polymers, thin-film dielectrics, lithium niobate, indium phosphide, gallium arsenide, magneto-optic materials, and birefringent crystals. We then describe the most commonly used classes of optical device technology and present their pros and cons as well as the functions achieved to date in each of them. The technologies reviewed include passive, actuation, and active technologies. The passive technologies described include fused fibers, dispersion-compensating fiber, beam steering, Bragg gratings, diffraction gratings, holographic elements, thin-film filters, photonic crystals, microrings, and birefringent elements. The actuation technologies include thermo-optics, electro-optics, acousto-optics, magneto-optics, electroabsorption, liquid crystals, total internal reflection technologies, and mechanical actuation. The active technologies include heterostructures, quantum wells, rare-earth doping, dye doping, Raman amplification, and semiconductor amplification. We also investigate the use of different material systems and device technologies to achieve building-block functions, including lasers, amplifiers, detectors, modulators, polarization controllers, couplers, filters, switches, attenuators, isolators, circulators, wavelength converters, chromatic dispersion compensators, and polarization mode dispersion compensators. Some of the technologies presented are well established in the industry and in some cases have reached the commodity stage, others have recently become ready for commercial introduction, while some others

  19. Optical mounts for harsh environments

    NASA Astrophysics Data System (ADS)

    Mimovich, Mark E.; Griffee, Jonathan C.; Goodding, James C.

    2009-08-01

    Development and testing of a lightweight-kinematic optical mount with integrated passive vibration-and-shock mitigation technologies and simple / robust optical alignment functionality is presented. Traditionally, optical mounts are designed for use in laboratory environments where the thermal-mechanical environments are carefully controlled to preserve beam path conditions and background disturbances are minimized to facilitate precise optically based measurements. Today's weapon and surveillance systems, however, have optical sensor suites where static and dynamic alignment performance in the presence of harsh operating environments is required to nearly the same precision and where the system cannot afford the mass of laboratory-grade stabilized mounting systems. Jitter and alignment stability is particularly challenging for larger optics operating within moving vehicles and aircraft where high shock and significant temperature excursions occur. The design intent is to have the mount be suitable for integration into existing defense and security optical systems while also targeting new commercial and military components for improved structural dynamic and thermal distortion performance. A mount suitable for moderate-sized optics and an integrated disturbance-optical metrology system are described. The mount design has performance enhancements derived from the integration of proven aerospace mechanical vibration and shock mitigation technologies (i.e. multi-axis passive isolation and integral damping), precision alignment adjustment and lock-out functionality, high dimensional stability materials and design practices which provide benign optical surface figure errors under harsh thermal-mechanical loading. Optical jitter, alignment, and wave-front performance testing of an eight-inch-aperture optical mount based on this design approach are presented to validate predicted performance improvements over an existing commercial off-the-shelf (COTS) design.

  20. Payload Isolation System for Launch Vehicles

    DTIC Science & Technology

    1997-03-01

    Payload Isolation System for Launch Vehicles Paul S. Wilke, Conor D. Johnson CSA Engineering Palo Alto, CA Eugene R. Fosness Air Force Phillips ... Laboratory , PL/VTVD Kirkland AFB, NM Spie Smart Structures and Materials San Diego, CA March 1997 Copyright 1997 Society of Photo-Optical Instrumentation

  1. Isolated sleep paralysis

    MedlinePlus

    Sleep paralysis - isolated; Parasomnia - isolated sleep paralysis ... Episodes of isolated sleep paralysis last from a few seconds to 1 or 2 minutes. During these episodes the person is unable to move or ...

  2. Optical Metacages

    NASA Astrophysics Data System (ADS)

    Mirzaei, Ali; Miroshnichenko, Andrey E.; Shadrivov, Ilya V.; Kivshar, Yuri S.

    2015-11-01

    We suggest a novel strategy for spectrally selective optical shielding of arbitrary shaped volumes by arranging specifically designed two- or three-layer nanowires around an area that needs to be protected. We show that such nanowire shields preserve their functionality for almost arbitrary geometry, and we term such structures optical metacages. We analyze several designs of such optical metacages made from either metallic or dielectric materials with experimentally measured parameters. We employ a semianalytical approach and also verify our results by numerical simulations. We further study optical properties of the introduced metacages in both near- and far-field regions, as well as analyze their frequency selectivity and the vanishing backscattering regime.

  3. Optical engineering

    SciTech Connect

    Saito, T T

    1998-01-01

    The Optical Engineering thrust area at Lawrence Livermore National Laboratory (LLNL) was created in the summer of 1996 with the following main objectives: (1) to foster and stimulate leading edge optical engineering research and efforts key to carrying out LLNL's mission and enabling major new programs; (2) to bring together LLNL's broad spectrum of high level optical engineering expertise to support its programs. Optical engineering has become a pervasive and key discipline, with applications across an extremely wide range of technologies, spanning the initial conception through the engineering refinements to enhance revolutionary application. It overlaps other technologies and LLNL engineering thrust areas.

  4. Optical trapping

    PubMed Central

    Neuman, Keir C.; Block, Steven M.

    2006-01-01

    Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. PMID:16878180

  5. Optical computing.

    NASA Technical Reports Server (NTRS)

    Stroke, G. W.

    1972-01-01

    Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.

  6. Two-Stage Passive Vibration Isolator

    NASA Technical Reports Server (NTRS)

    Goullioud, Renaud; Gursel, Yekta; Neville, Timothy; Bronowicki, Allen J.; Platus, David; MacDonald, Rhonda

    2008-01-01

    The design and testing of a structural system were implemented to hold the optics of the planned Space Interferometry Mission (SIM) at positions and orientations characterized by vibrational translation and rotation errors of no more than a few nanometers or a few milliarcseconds, respectively. Much of the effort was devoted to a test bed for verifying the predicted behavior of a vibration- isolation structural subsystem working together with an active control system for positioning and orienting the SIM optics. There was considerable emphasis on the vibration-isolation subsystem, which was passive and comprised two stages. The main sources of vibration were six reaction wheels in an assembly denoted the "backpack." The first vibration-isolation stage consisted of hexapod isolator mounts - one for each reaction wheel - characterized by a natural vibration frequency of 10 Hz. The second stage was a set of three beams, disposed between the backpack and the structure that held the SIM optics, that were flexured such that they transmitted only bending loads, with a natural vibrational frequency and damping of about 5 Hz and 4 percent, respectively. Preliminary test results were presented and characterized as demonstrating the effectiveness of the two-stage vibration-isolation design.

  7. Optically controlled integrated optical switch

    NASA Astrophysics Data System (ADS)

    Soref, R. A.

    1986-02-01

    This invention relates to an optically controlled integrated optical switch having a body made up of entirely crystalline silicon. More specifically, the body has a pair of channel waveguides intersecting at an X-like configuration forming therein an intersection crossover region. An electrically controlled optical source is positioned over the crossover region to shine intense, short-wave light on the crossover region in order to generate numerous electron-hole pairs in the waveguide material. These charge carriers alter the refractive index of the intersection region. A controllable current source is used to adjust the optical output power of the optical source. This, in turn, changes the amount of optical cross coupling of light between the intersecting waveguides.

  8. Compensation of thermally induced polarisation distortions in Faraday isolators

    SciTech Connect

    Khazanov, E A

    1999-01-31

    Two new Faraday isolator designs are proposed. They make it possible to compensate partly for the depolarisation of radiation which occurs in magneto-optical elements because of the photoelastic effect caused by heating associated with the absorption of laser radiation. Analytic and numerical comparisons of the new and traditional designs demonstrate a significant (by orders of magnitude) increase in the isolation ratio of the new isolators. The results obtained indicate that it should be possible to construct a Faraday isolator with the isolation ratio of 30 dB for laser radiation with an average power of several kilowatts. (laser applications and other topics in quantum electronics)

  9. Optical interconnection of optical modules

    NASA Astrophysics Data System (ADS)

    Schamschula, Marius P.; Caulfield, H. J.; Shamir, Joseph

    1990-12-01

    The most plausible possible uses of nonlinear optics as the bases for interconnections among complex optical modules are evaluated, with a view to such applications as neural networks that entail large numbers of interconnections and numerous stages. Optical interconnection allows such a system to be composed of many modules as well as to incorporate switching- and amplification-function optical nonlinearities. While it is possible to achieve a pixel-by-pixel, diffraction-limited flat-field relay with nonlinearity, where the interconnect allows for cascadability, the wave-particle duality is destroyed between stages.

  10. Optical testing

    NASA Technical Reports Server (NTRS)

    Wyant, James; Hochberg, Eric; Breault, Robert; Greivenkamp, John; Hunt, Gary; Mason, Pete; Mcguire, James; Meinel, Aden; Morris, Mike; Scherr, Larry

    1992-01-01

    Optical testing is one of the most vital elements in the process of preparing an optical instrument for launch. Without well understood, well controlled, and well documented test procedures, current and future mission goals will be jeopardized. We should keep in mind that the reason we test is to provide an opportunity to catch errors, oversights, and problems on the ground, where solutions are possible and difficulties can be rectified. Consequently, it is necessary to create tractable test procedures that truly provide a measure of the performance of all optical elements and systems under conditions which are close to those expected in space. Where testing is not feasible, accurate experiments are required in order to perfect models that can exactly predict the optical performance. As we stretch the boundaries of technology to perform more complex space and planetary investigations, we must expand the technology required to test the optical components and systems which we send into space. As we expand the observational wavelength ranges, so must we expand our range of optical sources and detectors. As we increase resolution and sensitivity, our understanding of optical surfaces to accommodate more stringent figure and scatter requirements must expand. Only with research and development in these areas can we hope to achieve success in the ever increasing demands made on optical testing by the highly sophisticated missions anticipated over the next two decades. Technology assessment and development plan for surface figure, surface roughness, alignment, image quality, radiometric quantities, and stray light measurement are presented.

  11. Camera Optics.

    ERIC Educational Resources Information Center

    Ruiz, Michael J.

    1982-01-01

    The camera presents an excellent way to illustrate principles of geometrical optics. Basic camera optics of the single-lens reflex camera are discussed, including interchangeable lenses and accessories available to most owners. Several experiments are described and results compared with theoretical predictions or manufacturer specifications.…

  12. Optical distance measuring instrument

    NASA Technical Reports Server (NTRS)

    Abshire, J. B. (Inventor)

    1986-01-01

    An optical instrument, such as a stability monitor or a target range finder, uses an unstabilized laser to project a composite optical signal of coherent light having two naturally occurring longitudinal mode components. A beamsplitter divides the signal into a reference beam which is directed toward one photodetector and a transmitted beam which illuminates and is reflected from a distant target onto a second photodetector optically isolated from the first photodetector. Both photodetectors are operated on the square law principle to provide electrical signals modulated at a frequency equal to the separation between the frequencies of the two longitudinal mode components of the optical signal projected by the laser. Slight movement of the target may be detected and measured by electrically monitoring the phase difference between the two signals provided by the photodetectors and the range of the target measured with the aid of a microprocessor by changing the separation between the longitudinal modes by shifting the length of the resonator cavity in an iterative series of increments.

  13. Optical biosensors

    PubMed Central

    Damborský, Pavel; Švitel, Juraj

    2016-01-01

    Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. PMID:27365039

  14. GREAT optics

    NASA Astrophysics Data System (ADS)

    Wagner-Gentner, Armin; Graf, Urs U.; Philipp, Martin; Rabanus, David; Stutzki, Jürgen

    2004-10-01

    The German REceiver for Astronomy at Terahertz frequencies (GREAT) is a first generation PI instrument for the SOFIA telescope, developed by a collaboration between the MPIfR, KOSMA, DLR, and the MPAe. The first three institutes each contribute one heterodyne receiver channel to operate at 1.9, 2.7 and 4.7 THz, respectively. A later addition of a e.g. 1.4 THz channel is planned. The GREAT instrument is developed to carry two cryostats at once. That means that any two of the three frequencies can be observed simultaneously. Therefore, we need to be able to quickly exchange the optics benches, the local oscillator (LO) subsystems, and the cryostats containing the mixer devices. This demands a high modularity and flexibility of our receiver concept. Our aim is to avoid the need for realignment when swapping receiver channels. After an overview of the common GREAT optics, a detailed description of several parts (optics benches, calibration units, diplexer, focal plane imager) is given. Special emphasis is given to the LO optics of the KOSMA 1.9 THz channel, because its backward wave oscillator has an astigmatic output beam profile, which has to be corrected for. We developed astigmatic off-axis mirrors to compensate this astigmatism. The mirrors are manufactured in-house on a 5 axis CNC milling machine. We use this milling machine to obtain optical components with highest surface accuracy (about 5 microns) appropriate for these wavelengths. Based on the CNC machining capabilities we present our concept of integrated optics, which means to manufacture optical subsystems monolithically. The optics benches are located on three point mounts, which in conjunction with the integrated optics concept ensure the required adjustment free optics setup.

  15. Georges Sagnac: A life for optics

    NASA Astrophysics Data System (ADS)

    Darrigol, Olivier

    2014-12-01

    Georges Sagnac is mostly known for the optical effect in rotating frames that he demonstrated in 1913. His scientific interests were quite diverse: they included photography, optical illusions, X-ray physics, radioactivity, the blue of the sky, anomalous wave propagation, interferometry, strioscopy, and acoustics. An optical theme nonetheless pervaded his entire œuvre. Within optics, an original theory of the propagation of light motivated most of his investigations, from an ingenious explanation of the Fresnel drag, through the discovery of the Sagnac effect, to his quixotic defense of an alternative to relativity theory. Optical analogies efficiently guided his work in other domains. Optics indeed was his true passion. He saw himself as carrying the torch of the two great masters of French optics, Augustin Fresnel and Hippolyte Fizeau. In this mission he overcame his poor health and labored against the modernist tide, with much success originally and bitter isolation in the end. xml:lang="fr"

  16. 45-dB Faraday isolator for 100 W average radiation power

    SciTech Connect

    Andreev, N F; Palashov, O V; Potemkin, A K; Sergeev, Aleksandr M; Khazanov, E A; Reitze, D H

    2000-12-31

    It is demonstrated experimentally that at high average radiation power, the optical isolation in the recently proposed design of a Faraday isolator is substantially higher than in the conventional scheme. The Faraday isolator with the isolation of 45 dB at the radiation power of 100 W is implemented. The data obtained show that a 30-dB isolator for the average laser radiation power of 1 kW can be realised. (laser applications and other topics in quantum electronics)

  17. Fiber optic coupled optical sensor

    DOEpatents

    Fleming, Kevin J.

    2001-01-01

    A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

  18. Stem Cell Ophthalmology Treatment Study (SCOTS) for retinal and optic nerve diseases: a case report of improvement in relapsing auto-immune optic neuropathy.

    PubMed

    Weiss, Jeffrey N; Levy, Steven; Benes, Susan C

    2015-09-01

    We present the results from a patient with relapsing optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board approved clinical trial and has become the largest ophthalmology stem cell study registered at the National Institutes of Health to date (www.clinicaltrials.gov Identifier NCT 01920867). SCOTS utilizes autologous bone marrow-derived stem cells (BMSCs) for treatment of retinal and optic nerve diseases. Pre-treatment and post-treatment comprehensive eye exams of a 54 year old female patient were performed both at the Florida Study Center, USA and at The Eye Center of Columbus, USA. As a consequence of a relapsing optic neuritis, the patient's previously normal visual acuity decreased to between 20/350 and 20/400 in the right eye and to 20/70 in the left eye. Significant visual field loss developed bilaterally. The patient underwent a right eye vitrectomy with injection of BMSCs into the optic nerve of the right eyeand retrobulbar, subtenon and intravitreal injection of BMSCs in the left eye. At 15 months after SCOTS treatment, the patient's visual acuity had improved to 20/150 in the right eye and 20/20 in the left eye. Bilateral visual fields improved markedly. Both macular thickness and fast retinal nerve fiber layer thickness were maximally improved at 3 and 6 months after SCOTS treatment. The patient also reduced her mycophenylate dose from 1,500 mg per day to 500 mg per day and required no steroid pulse therapy during the 15-month follow up.

  19. Optical Firmware

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.

    1989-01-01

    Data-processing system exploits high speeds inherent in optical elements. Instruction sets for different computer operations reside on different external memory chips. Laser diodes activated for each operation generate light, reflected by holographic optical element to designated receptors in arithmetic and logic unit. Pattern of light beams embodies instruction set at given instant. With potential ability to reprogram in real time, conceptual system applicable to task-driven programming or artificial intelligence.

  20. Optical disks

    NASA Technical Reports Server (NTRS)

    Lopez-Swafford, B.

    1986-01-01

    A comprehensive overview of the different types of optical storage technology is presented. Research efforts to integrate this technology into the VAX/VMS environment are discussed. In addition, plans for future applications of optical disk technology are described. The applications should prove to be beneficial to the NSSDC user community as a whole. Of particular interest is the concentration on the collaboration with the Dynamics Explorer project.

  1. Ground Isolation Circuit for Isolating a Transmission Line from Ground Interference

    NASA Technical Reports Server (NTRS)

    Davidson, Craig A. (Inventor)

    1996-01-01

    This invention relates generally to a system for isolating ground interference from a transmission line, e.g., a ground isolation circuit for isolating a wideband transmission signal (such as a video signal) from ground by modulating the base signal on a carrier signal to permit the transmission signal to be isolated. In one embodiment, the circuit includes a pair of matched mixer circuits, each of which receives a carrier signal from the same oscillator circuit. The first mixer circuit also receives the baseband signal input, after appropriate conditioning, and modulates the baseband signal onto the carrier signal. In a preferred embodiment the carrier signal has a predetermined frequency which is at least two times the frequency of the baseband signal. The modulated signal (which can comprise an rf signal) is transmitted via an rf transmission line to the second mixer, which demodulates the rf signal to recover the baseband signal. Each port of the mixer connects to an isolation transformer to ensure isolation from ground interference. The circuit is considered to be of commercial value in that it can provide isolation between transmitting and receiving circuits, e.g., ground isolation for television circuits or high frequency transmitters, without the need for video transformers or optical isolators, thereby reducing the complexity, power consumption, and weight of the system.

  2. Nonreciprocity and magnetic-free isolation based on optomechanical interactions

    PubMed Central

    Ruesink, Freek; Miri, Mohammad-Ali; Alù, Andrea; Verhagen, Ewold

    2016-01-01

    Nonreciprocal components, such as isolators and circulators, provide highly desirable functionalities for optical circuitry. This motivates the active investigation of mechanisms that break reciprocity, and pose alternatives to magneto-optic effects in on-chip systems. In this work, we use optomechanical interactions to strongly break reciprocity in a compact system. We derive minimal requirements to create nonreciprocity in a wide class of systems that couple two optical modes to a mechanical mode, highlighting the importance of optically biasing the modes at a controlled phase difference. We realize these principles in a silica microtoroid optomechanical resonator and use quantitative heterodyne spectroscopy to demonstrate up to 10 dB optical isolation at telecom wavelengths. We show that nonreciprocal transmission is preserved for nondegenerate modes, and demonstrate nonreciprocal parametric amplification. These results open a route to exploiting various nonreciprocal effects in optomechanical systems in different electromagnetic and mechanical frequency regimes, including optomechanical metamaterials with topologically non-trivial properties. PMID:27897165

  3. Psychopathology of social isolation

    PubMed Central

    Baek, Sang-Bin

    2014-01-01

    The most important defining factor of being human is the use of symbolic language. Language or communication problem occurs during the growth, the child will have a higher risk of social isolation and then the survival will be threatened constantly. Today, adolescents and youths are familiar with computer and smart-phone devices, and communication with others by these devices is easy than face-to-face communication. As adolescents and youths live in the comfortable and familiar cyber-world rather than actively participating real society, so they make social isolation. Extreme form of this isolation in adolescents and youths is so-called Socially Withdrawn Youth. In this study, the psychopathological factors inducing social isolation were discussed. Development stages of social isolation in relation with types of social isolation, Ego-syntonic isolation and Ego-dystonic isolation, were also considered. PMID:25061592

  4. Optical memory

    DOEpatents

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  5. CODEX optics

    NASA Astrophysics Data System (ADS)

    Delabre, Bernard; Manescau, Antonio

    2010-07-01

    CODEX is a high resolution spectrograph for the ESO E-ELT. A classical spectrograph can only achieve a resolution of about 120.000 on a 42 m telescope with extremely large echelle gratings and cameras. This paper describes in detail the optical concept of CODEX, which uses only optical elements size similar to those in current high resolution spectrographs. This design is based on slicers, anamorphic beams and slanted VPHG as cross dispersers. In this new version of the CODEX design, no special expensive materials as calcium fluoride or abnormal dispersion glasses are needed. The optical quality is excellent and compatible with 10K x 10K detectors with 10 μm pixels.

  6. Kindergarten' optics

    NASA Astrophysics Data System (ADS)

    M. Costa, Manuel F.; Campos, Júlia; Lira, Madalena; Franco, Sandra

    2009-06-01

    The introduction to our school' students of the wonders of light and optics and its understanding can and should be made as extensively as possible. As soon as at kindergarten level! A hands-on approach leading the students to observe experiment and discover themselves in a critical committed and active way the different aspects of light and optics should be employed at all school levels and must be the main driving pedagogical practice of all learning process of science and technology. In this communication we present a series of experiments and support material designed in this hands-on perspective to be used to introduce the study of optics to kindergarten and early basic school students. A critical evaluation of the first results of the application of these material with students aged 4 to 10 years will be presented.

  7. Optical coupler

    DOEpatents

    Majewski, Stanislaw; Weisenberger, Andrew G.

    2004-06-15

    In a camera or similar radiation sensitive device comprising a pixilated scintillation layer, a light guide and an array of position sensitive photomultiplier tubes, wherein there exists so-called dead space between adjacent photomultiplier tubes the improvement comprising a two part light guide comprising a first planar light spreading layer or portion having a first surface that addresses the scintillation layer and optically coupled thereto at a second surface that addresses the photomultiplier tubes, a second layer or portion comprising an array of trapezoidal light collectors defining gaps that span said dead space and are individually optically coupled to individual position sensitive photomultiplier tubes. According to a preferred embodiment, coupling of the trapezoidal light collectors to the position sensitive photomultiplier tubes is accomplished using an optical grease having about the same refractive index as the material of construction of the two part light guide.

  8. Optical analyzer

    DOEpatents

    Hansen, A.D.

    1987-09-28

    An optical analyzer wherein a sample of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter is placed in a combustion tube, and light from a light source is passed through the sample. The temperature of the sample is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample is detected as the temperature is raised. A data processor, differentiator and a two pen recorder provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample. These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample. Additional information is obtained by repeating the run in different atmospheres and/or different rates or heating with other samples of the same particulate material collected on other filters. 7 figs.

  9. Optical resonator

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  10. Optical Correlation

    NASA Technical Reports Server (NTRS)

    Cotariu, Steven S.

    1991-01-01

    Pattern recognition may supplement or replace certain navigational aids on spacecraft in docking or landing activities. The need to correctly identify terrain features remains critical in preparation of autonomous planetary landing. One technique that may solve this problem is optical correlation. Correlation has been successfully demonstrated under ideal conditions; however, noise significantly affects the ability of the correlator to accurately identify input signals. Optical correlation in the presence of noise must be successfully demonstrated before this technology can be incorporated into system design. An optical correlator is designed and constructed using a modified 2f configuration. Liquid crystal televisions (LCTV) are used as the spatial light modulators (SLM) for both the input and filter devices. The filter LCTV is characterized and an operating curve is developed. Determination of this operating curve is critical for reduction of input noise. Correlation of live input with a programmable filter is demonstrated.

  11. Isolation in Early Childhood.

    ERIC Educational Resources Information Center

    Rogers, Sinclair

    This paper presents information on isolated children and describes a study being undertaken to examine the role of isolation in reported cases of child abuse and neglect. The effects of extreme isolation on language and psychological development are emphasized. The importance of early socialization is seen in relation to normal development.…

  12. Optical switch

    DOEpatents

    Reedy, Robert P.

    1987-01-01

    An optical switching device (10) is provided whereby light from a first glass fiber (16) or a second glass fiber (14) may be selectively transmitted into a third glass fiber (18). Each glass fiber is provided with a focusing and collimating lens system (26, 28, 30). In one mode of operation, light from the first glass fiber (16) is reflected by a planar mirror (36) into the third glass fiber (18). In another mode of operation, light from the second glass fiber (14) passes directly into the third glass fiber (18). The planar mirror (36) is attached to a rotatable table (32) which is rotated to provide the optical switching.

  13. Performance of a launch and on-orbit isolator

    NASA Astrophysics Data System (ADS)

    Boyd, Jim; Hyde, T. Tupper; Osterberg, Dave; Davis, Torey

    2001-08-01

    A recently qualified Honeywell vibration isolation system does two things well. It supports and protects its payload during launch environments, and subsequently provides micro-inch level jitter reduction on-orbit. An elliptical hexapod provides six-degree-of-freedom support and isolation. The fluid-damped D-Strut isolation system maintains its payload optical alignment after vibration and thermal exposure. Vibration tests at one micro-inch input and at one- tenth of an inch input show almost identical damping and isolation responses. The 70-lb test payload was made from wood with an aluminum backbone. The payload provided accurate mounting geometries for the six isolator struts, and precision locations for ten accelerometers and an optical cube. Shock testing, launch-level random vibration, and launch sine vibration were imposed. The system was also subjected to thermal cycling. Functional transmissibility tests were performed before, midway, and after launch environments, at 0.25-g and 2.5-g sine input levels. Honeywell's Matlab Isolator Design Tool predicted transmissibility between 6 degrees-of-freedom inputs and the six rigid body outputs. Another analysis code took these 36 transmissibilities and used optical element transfer functions to calculate an overall jitter number. Finally, 18 measured transmissibility curves from functional tests were fed through the optical jitter code.

  14. Novel Anti-idiotype Antibody Therapy for Lipooligosaccharide-Induced Experimental Autoimmune Neuritis: Use Relevant to Guillain-Barré Syndrome

    PubMed Central

    Usuki, S.; Taguchi, K.; Thompson, S.A.; Chapman, P.B.; Yu, R.K.

    2010-01-01

    Campylobacteriosis is a frequent antecedent event in Guillain-Barré syndrome (GBS), inducing high-titer serum antibodies for ganglioside antigens in the peripheral nervous system (PNS). Molecular mimicry between the lipooligosaccharide (LOS) component of Campylobacter jejuni and human peripheral nerve gangliosides is believed to play an important role in the pathogenesis of GBS. Conventional treatment strategies for patients with GBS include plasmapheresis, intravenous immunoglobulin (IVIG), and immunosuppression, which are invasive or relatively ineffective. In this study, we used our animal model of GBS, in which Lewis rats were immunized with GD3-like LOS isolated from C. jejuni. The animals developed anti-GD3 ganglioside antibodies and manifested neuromuscular dysfunction. To develop novel therapeutic strategies, we treated the animals by intraperitoneal administration of an anti-GD3 antiidiotype monoclonal antibody (BEC2) that specifically interacts with the pathogenic antibody. The treated animals had a remarkable reduction of anti-GD3 antibody titers and improvement of motor nerve functions. The results suggest that ganglioside mimics, such as antiidiotype antibodies, may be powerful reagents for therapeutic intervention in GBS by neutralizing specific pathogenic antiganglioside antibodies. PMID:20077429

  15. Diophantine Optics

    NASA Astrophysics Data System (ADS)

    Rouan, D.

    2016-09-01

    What I call Diophantine optics is the exploitation in optics of some remarkable algebraic relations between powers of integers. The name comes from Diophantus of Alexandria, a greek mathematician, known as the father of algebra. He studied polynomial equations with integer coefficients and integer solutions, called diophantine equations. Since constructive or destructive interferences are playing with optical path differences which are multiple integer (odd or even) of λ/2 and that the complex amplitude is a highly non-linear function of the optical path difference (or equivalently of the phase), one can understand that any Taylor development of this amplitude implies powers of integers. This is the link with Diophantine equations. We show how, especially in the field of interferometry, remarkable relations between powers of integers can help to solve several problems, such as achromatization of a phase shifter or deep nulling efficiency. It appears that all the research that was conducted in this frame of thinking, relates to the field of detection of exoplanets, a very active domain of astrophysics today.

  16. Optical profilometer

    NASA Astrophysics Data System (ADS)

    Wieloszyńska, Aleksandra; StrÄ kowski, Marcin

    2016-09-01

    The profilometry plays a huge role in the most fields of science and technology. It allows to measure the profile of the surface with high-resolution. This technique is used in the fields like optic, electronic, medicine, automotive, and much more. The aim of the current work was to design and build optical profilometer based on the interference phenomena. The developed device has been working with He-Ne laser (632.8 nm). The optical parts have been chosen in order to reach the sized 2.0 mm x 1.6 mm of scanning area. The setup of the profilometer is based on Twyman-Green interferometer. Therefore, the phase distribution of the backreflected light from measured surface is recorded. The measurements are carried out with the aid of multiframe algorithms. In this approach we have used the Hariharan algorithm to obtain the exact value of the recorded phase. During tests, which have been carried out in order to check the functionality of the device, the interference patterns have been recoded and processed in order to obtain the 3D profile of measured surface. In this contribution the setup of the optical system, as well as signal processing methods are going to be presented. The brief discussion about the advantages and disadvantages, and usefulness of this approach will be carried out.

  17. Pulsed Optics

    NASA Astrophysics Data System (ADS)

    Hirlimann, C.

    Optics is the field of physics which comprises knowledge on the interaction between light and matter. When the superposition principle can be applied to electromagnetic waves or when the properties of matter do not depend on the intensity of light, one speaks of linear optics. This situation occurs with regular light sources such as light bulbs, low-intensity light-emitting diodes and the sun. With such low-intensity sources the reaction of matter to light can be characterized by a set of parameters such as the index of refraction, the absorption and reflection coefficients and the orientation of the medium with respect to the polarization of the light. These parameters depend only on the nature of the medium. The situation changed dramatically after the development of lasers in the early sixties, which allowed the generation of light intensities larger than a kilowatt per square centimeter. Actual large-scale short-pulse lasers can generate peak powers in the petawatt regime. In that large-intensity regime the optical parameters of a material become functions of the intensity of the impinging light. In 1818 Fresnel wrote a letter to the French Academy of Sciences in which he noted that the proportionality between the vibration of the light and the subsequent vibration of matter was only true because no high intensities were available. The intensity dependence of the material response is what usually defines nonlinear optics.

  18. Optical pantograph

    NASA Technical Reports Server (NTRS)

    Belew, Robert R. (Inventor); Davis, Donald E. (Inventor)

    1976-01-01

    An optical pantograph for directing light beams and the like from a source to a receiver according to the movement of a pointer. The device can be used for, among other things, directing a laser beam and the like to a target for etching patterns on a target according to the movement of a pointer relative to a pattern trace.

  19. Skin optics

    SciTech Connect

    van Gemert, M.J.; Jacques, S.L.; Sterenborg, H.J.; Star, W.M.

    1989-12-01

    Quantitative dosimetry in the treatment of skin disorders with (laser) light requires information on propagation of light in the skin related to the optical properties of the individual skin layers. This involves the solution of the integro-differential equation of radiative transfer in a model representing skin geometry, as well as experimental methods to determine the optical properties of each skin layer. These activities are unified under the name skin optics. This paper first reviews the current status of tissue optics, distinguishing between the cases of: dominant absorption, dominant scattering, and scattering about equal to absorption. Then, previously published data as well as some current unpublished data on (human) stratum corneum, epidermis and dermis, have been collected and/or (re)analyzed in terms of absorption coefficient, scattering coefficient, and anisotropy factor of scattering. The results are that the individual skin layers show strongly forward scattering (anisotropy factors between 0.7 and 0.9). The absorption and scattering data show that for all wavelengths considered scattering is much more important than absorption. Under such circumstances, solutions to the transport equation for a multilayer skin model and finite beam laser irradiation are currently not yet available. Hence, any quantitative dosimetry for skin treated with (laser) light is currently lacking.

  20. Optical chaos

    SciTech Connect

    Milonni, P.W.

    1989-01-01

    The theoretical and experimental status of chaos in nonlinear optics and laser physics will be reviewed. Attention will then be focused on the possibility of chaotic behavior in individual atoms and molecules driven by intense radiation fields. 46 refs., 7 figs.

  1. Optical Crystals

    ERIC Educational Resources Information Center

    Bergsten, Ronald

    1974-01-01

    Discusses the production and structure of a sequence of optical crystals which can serve as one-, two-, and three-dimensional diffraction plates to illustrate diffraction patterns by using light rather than x-rays or particles. Applications to qualitative presentations of Laue theory at the secondary and college levels are recommended. (CC)

  2. Optical Magnetometry

    NASA Astrophysics Data System (ADS)

    Budker, Dmitry; Kimball, Derek F. Jackson

    2013-03-01

    Part I. Principles and Techniques: 1. General principles and characteristics of optical magnetometers D. F. Jackson Kimball, E. B. Alexandrov and D. Budker; 2. Quantum noise in atomic magnetometers M. V. Romalis; 3. Quantum noise, squeezing, and entanglement in radio-frequency optical magnetometers K. Jensen and E. S. Polzik; 4. Mx and Mz magnetometers E. B. Alexandrov and A. K. Vershovskiy; 5. Spin-exchange-relaxation-free (serf) magnetometers I. Savukov and S. J. Seltzer; 6. Optical magnetometry with modulated light D. F. Jackson Kimball, S. Pustelny, V. V. Yashchuk and D. Budker; 7. Microfabricated atomic magnetometers S. Knappe and J. Kitching; 8. Optical magnetometry with nitrogen-vacancy centers in diamond V. M. Acosta, D. Budker, P. R. Hemmer, J. R. Maze and R. L. Walsworth; 9. Magnetometry with cold atoms W. Gawlik and J. M. Higbie; 10. Helium magnetometers R. E. Slocum, D. D. McGregor and A. W. Brown; 11. Surface coatings for atomic magnetometry S. J. Seltzer, M.-A. Bouchiat and M. V. Balabas; 12. Magnetic shielding V. V. Yashchuk, S.-K. Lee and E. Paperno; Part II. Applications: 13. Remote detection magnetometry S. M. Rochester, J. M. Higbie, B. Patton, D. Budker, R. Holzlöhner and D. Bonaccini Calia; 14. Detection of nuclear magnetic resonance with atomic magnetometers M. P. Ledbetter, I. Savukov, S. J. Seltzer and D. Budker; 15. Space magnetometry B. Patton, A. W. Brown, R. E. Slocum and E. J. Smith; 16. Detection of biomagnetic fields A. Ben-Amar Baranga, T. G. Walker and R. T. Wakai; 17. Geophysical applications M. D. Prouty, R. Johnson, I. Hrvoic and A. K. Vershovskiy; Part III. Broader Impact: 18. Tests of fundamental physics with optical magnetometers D. F. Jackson Kimball, S. K. Lamoreaux and T. E. Chupp; 19. Nuclear magnetic resonance gyroscopes E. A. Donley and J. Kitching; 20. Commercial magnetometers and their application D. C. Hovde, M. D. Prouty, I. Hrvoic and R. E. Slocum; Index.

  3. Forty Years of Research on Isolated Galaxies

    NASA Astrophysics Data System (ADS)

    Sulentic, J.

    2010-10-01

    Isolated galaxies have not been a hot topic over the past four decades. This is partly due to uncertainties about their existence. Are there galaxies isolated enough to be interesting? Do they exist in sufficient numbers to be statistically useful? Most attempts to compile isolated galaxy lists were marginally successful-too small number and not very isolated galaxies. If really isolated galaxies do exist then their value becomes obvious in a Universe where effects of interactions and environment (i.e. nurture) are important. They provide a means for better quantifying effects of nurture. The Catalog of Isolated Galaxies (CIG) compiled by Valentina Karachentseva appeared near the beginning of the review period. It becomes the focus of this review because of its obvious strengths and because the AMIGA project has increased its utility through a refinement (a vetted CIG). It contains almost 1000 galaxies with nearest neighbor crossing times of 1--3 Gyr. It is large enough to serve as a zero-point or control sample. The galaxies in the CIG (and the distribution of galaxy types) may be significantly different than those in even slightly richer environments. The AMIGA-CIG, and future iterations, may be able to tell us something about galaxy formation. It may also allow us to better define intrinsic (natural) correlations like e.g. Fisher-Tully and FIR-OPTICAL. Correlations can be better defined when the dispersion added by external stimuli (nurture) is minimized or removed.

  4. Preparation and isolation of dityrosine.

    PubMed

    Malanik, V; Ledvina, M

    1979-01-01

    A new procedure for the isolation of dityrosine has been developed. Tyrosine was oxidized by means of incubation both with hydrogen peroxide and horse-radish peroxidase. The reaction mixture was separated by permeation chromatography on Sephadex G-10 being monitored at 280 and 310 nm spectrophotometrically. The dityrosine fraction was freeze-dried and purified on a cation-exchange column (in acidic citrate buffer). The purified fraction was desalted and freeze-dried. The yield was 96 mg of homogenous dityrosine per 1 g of D,L-tyrosine. Some physico-chemical constants of the preparation were measured (optical characteristics with U.V. and I.R. spectra, fluorescence spectra, chromatography on an amino acid analyzer).

  5. Soft optics in intelligent optical networks

    NASA Astrophysics Data System (ADS)

    Shue, Chikong; Cao, Yang

    2001-10-01

    In addition to the recent advances in Hard-optics that pushes the optical transmission speed, distance, wave density and optical switching capacity, Soft-optics provides the necessary intelligence and control software that reduces operational costs, increase efficiency, and enhances revenue generating services by automating optimal optical circuit placement and restoration, and enabling value-added new services like Optical VPN. This paper describes the advances in 1) Overall Hard-optics and Soft-optics 2) Layered hierarchy of Soft-optics 3) Component of Soft-optics, including hard-optics drivers, Management Soft-optics, Routing Soft-optics and System Soft-optics 4) Key component of Routing and System Soft-optics, namely optical routing and signaling (including UNI/NNI and GMPLS signaling). In summary, the soft-optics on a new generation of OXC's enables Intelligent Optical Networks to provide just-in-time service delivery and fast restoration, and real-time capacity management that eliminates stranded bandwidth. It reduces operational costs and provides new revenue opportunities.

  6. Biphoton optics

    NASA Astrophysics Data System (ADS)

    Strekalov, Dmitry Vladimirovich

    1997-10-01

    The subject of this dissertation is the study of the two- photon entanglement. This phenomenon has been paid a great deal of attention since 1935, when A. Einstein, B. Podolsky and N. Rosen asked their famous question, 'Can quantum-mechanical description of physical reality be considered complete?' An entangled system behavior is inconsistent with many classical concepts. Therefore, the understanding of two-photon entanglement is important for the foundations of quantum theory. A two-photon entangled sate represents a two-photon, or a biphoton, rather than two photons. The concept of biphoton as a single nonlocal quantum object is fundamentally different from the concept of a photon pair, as has been experimentally demonstrated in the present dissertation. Two-photon entanglement gives rise to unusual 'ghost' interference and diffraction, nonlocal geometrical phase, and other quantum phenomena originally studied in the present dissertation. The variety of available results calls for bringing them into a general system which we call Biphoton Optics. This is the main goal of this dissertation. Biphoton optics operate with two-photon wave packets, or with an equivalent concept of advanced wave. We show that in the framework of the advanced wave concept two-photon phenomena can be effectively described in terms of classical optics. Therefore the biphoton optics has the same structure as the classical optics. It includes two- photon geometrical optics, dispersion and frequency beating, polarization effects, interference, diffraction, and geometrical phase. All these two-photon effects are represented by experiments included in this dissertation. Our approach does not make two-photon quantum effects 'classical', however. It should be understood that the advanced wave model operates with counter-propagation in time which does not correspond to any real physical process. Therefore it is just a model, but it is clearly a great advantage to have such a model that is both

  7. Optic nerve atrophy

    MedlinePlus

    Optic atrophy; Optic neuropathy ... There are many causes of optic atrophy. The most common is poor blood flow. This is called ischemic optic neuropathy. The problem most often affects older adults. ...

  8. Magneto-optical non-reciprocal devices in silicon photonics.

    PubMed

    Shoji, Yuya; Mizumoto, Tetsuya

    2014-02-01

    Silicon waveguide optical non-reciprocal devices based on the magneto-optical effect are reviewed. The non-reciprocal phase shift caused by the first-order magneto-optical effect is effective in realizing optical non-reciprocal devices in silicon waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer enhances the magneto-optical phase shift, which reduces the device footprints. A surface activated direct bonding technique was developed to integrate a magneto-optical garnet crystal on the silicon waveguides. A silicon waveguide optical isolator based on the magneto-optical phase shift was demonstrated with an optical isolation of 30 dB and insertion loss of 13 dB at a wavelength of 1548 nm. Furthermore, a four port optical circulator was demonstrated with maximum isolations of 15.3 and 9.3 dB in cross and bar ports, respectively, at a wavelength of 1531 nm.

  9. Magneto-optical non-reciprocal devices in silicon photonics

    PubMed Central

    Shoji, Yuya; Mizumoto, Tetsuya

    2014-01-01

    Silicon waveguide optical non-reciprocal devices based on the magneto-optical effect are reviewed. The non-reciprocal phase shift caused by the first-order magneto-optical effect is effective in realizing optical non-reciprocal devices in silicon waveguide platforms. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer enhances the magneto-optical phase shift, which reduces the device footprints. A surface activated direct bonding technique was developed to integrate a magneto-optical garnet crystal on the silicon waveguides. A silicon waveguide optical isolator based on the magneto-optical phase shift was demonstrated with an optical isolation of 30 dB and insertion loss of 13 dB at a wavelength of 1548 nm. Furthermore, a four port optical circulator was demonstrated with maximum isolations of 15.3 and 9.3 dB in cross and bar ports, respectively, at a wavelength of 1531 nm. PMID:27877640

  10. Multimode fiber optic wavelength division multiplexing

    NASA Technical Reports Server (NTRS)

    Spencer, J. L.

    1982-01-01

    Optical wavelength division multiplexing (WDM) systems, with signals transmitted on different wavelengths through a single optical fiber, can have increased bandwidth and fault isolation properties over single wavelength optical systems. Two WDM system designs that might be used with multimode fibers are considered and a general description of the components which could be used to implement the system are given. The components described are sources, multiplexers, demultiplexers, and detectors. Emphasis is given to the demultiplexer technique which is the major developmental component in the WDM system.

  11. Fiber optic monitoring device

    DOEpatents

    Samborsky, James K.

    1993-01-01

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  12. Optical gyroscope

    NASA Technical Reports Server (NTRS)

    Goldstein, R. M.; Goss, W. C.

    1978-01-01

    Instrument uses phase difference between two beams of light to measure rotation. It is considerably simpler and more reliable than conventional spinning-mass gyroscopes used for inertial guidance and is more compact, lighter, and potentially less expensive. Moreover, optical gyroscope requires no warmup period. Although conceived for spacecraft and satellite stabilization, gyroscope should also find applications in flight instruments for private, commercial, and military aircraft.

  13. Optics Research.

    DTIC Science & Technology

    2007-11-02

    Introduction vii Reports on Optics Research xi Organization xv I. LASER TECHNOLOGY AND PROPAGATION 1 A. CW Theory 1 1. Laser Propagation Through a...show that CW thermal bloom- ing can be considerably reduced by an initial phase correction of the laser beam. Several experiments were performed to...Teoste, R. Zimmerman, M. D. I. LASER TECHNOLOGY AND PROPAGATION A. CW THEORY 1. Laser Propagation Through a Turbulent Medium In

  14. Ocean Optics

    DTIC Science & Technology

    2014-05-01

    sensing and lidar , through measurements and models. 15. SUBJECT TERMS Remote sensing , ocean optics, lidar , underwater imaging, underwater turbulence...scanning system taking advantage of compressive sensing imaging techniques (B. O^ang et al.). Modeling is key in system design and performance...effect has been simulated using a fvlonte Carlo method (Z. Xu and D. K. P. Yue). Active sensing by the means of lidar eliminates many of the issues

  15. Optical Refrigeration

    DTIC Science & Technology

    2007-12-01

    1Optical Science and Engineering, Department of Physics & Astronomy, University of New Mexico , Albuquerque, New Mexico 87131, USA 2Los Alamos National...Laboratory, Los Alamos, New Mexico 87545, USA *e-mail: msb@unm.edu The term ‘laser cooling’ is most often associated with cooling dilute gases of...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of New Mexico ,Department of Physics & Astronomy

  16. Optical aeronomy

    SciTech Connect

    Solomon, S.C. )

    1991-01-01

    Optical measurements of thermospheric and ionospheric processes and their interpretation are reviewed and the chemical reactions and their effects on emissions are discussed. Also included are the phenomena which excite the airglow and aurora, i.e., the solar UV/EUV flux and auroral particle precipitation. Consideration is given to solar flux, atomic emissions, molecular emissions, hydrogen geocorona, and molecular oxygen and the green line nightglow.

  17. Module isolation devices

    DOEpatents

    Carolan, Michael Francis; Cooke, John Albert; Buzinski, Michael David

    2010-04-27

    A gas flow isolation device includes a gas flow isolation valve movable from an opened condition to a closed condition. The module isolation valve in one embodiment includes a rupture disk in flow communication with a flow of gas when the module isolation valve is in an opened condition. The rupture disk ruptures when a predetermined pressure differential occurs across it causing the isolation valve to close. In one embodiment the valve is mechanically linked to the rupture disk to maintain the valve in an opened condition when the rupture disk is intact, and which permits the valve to move into a closed condition when the rupture disk ruptures. In another embodiment a crushable member maintains the valve in an open condition, and the flow of gas passed the valve upon rupturing of the rupture disk compresses the crushable member to close the isolation valve.

  18. Mutation and premating isolation

    NASA Technical Reports Server (NTRS)

    Woodruff, R. C.; Thompson, J. N. Jr

    2002-01-01

    While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier to mate with. We now realize that premeiotic mutations are very common and will yield a cluster of progeny carrying the same new mutant allele. In this paper, we discuss the evidence for genetically simple premating isolation barriers and the role that clusters of an isolation mutation may play in initiating allopatric, and even sympatric, species divisions.

  19. Mutation and premating isolation.

    PubMed

    Woodruff, R C; Thompson, J N

    2002-11-01

    While premating isolation might be traceable to different genetic mechanisms in different species, evidence supports the idea that as few as one or two genes may often be sufficient to initiate isolation. Thus, new mutation can theoretically play a key role in the process. But it has long been thought that a new isolation mutation would fail, because there would be no other individuals for the isolation-mutation-carrier to mate with. We now realize that premeiotic mutations are very common and will yield a cluster of progeny carrying the same new mutant allele. In this paper, we discuss the evidence for genetically simple premating isolation barriers and the role that clusters of an isolation mutation may play in initiating allopatric, and even sympatric, species divisions.

  20. Foveated optics

    NASA Astrophysics Data System (ADS)

    Bryant, Kyle R.

    2016-05-01

    Foveated imaging can deliver two different resolutions on a single focal plane, which might inexpensively allow more capability for military systems. The following design study results provide starting examples, lessons learned, and helpful setup equations and pointers to aid the lens designer in any foveated lens design effort. Our goal is to put robust sensor in a small package with no moving parts, but still be able to perform some of the functions of a sensor in a moving gimbal. All of the elegant solutions are out (for various reasons). This study is an attempt to see if lens designs can solve this problem and realize some gains in performance versus cost for airborne sensors. We determined a series of design concepts to simultaneously deliver wide field of view and high foveal resolution without scanning or gimbals. Separate sensors for each field of view are easy and relatively inexpensive, but lead to bulky detectors and electronics. Folding and beam-combining of separate optical channels reduces sensor footprint, but induces image inversions and reduced transmission. Entirely common optics provide good resolution, but cannot provide a significant magnification increase in the foveal region. Offsetting the foveal region from the wide field center may not be physically realizable, but may be required for some applications. The design study revealed good general guidance for foveated optics designs with a cold stop. Key lessons learned involve managing distortion, telecentric imagers, matching image inversions and numerical apertures between channels, reimaging lenses, and creating clean resolution zone splits near internal focal planes.

  1. Optical analyzer

    DOEpatents

    Hansen, Anthony D.

    1989-01-01

    An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19). Additional information is obtained by repeating the run in different atmospheres and/or different rates of heating with other samples of the same particulate material collected on other filters.

  2. Optical analyzer

    DOEpatents

    Hansen, Anthony D.

    1989-02-07

    An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19). Additional information is obtained by repeating the run in different atmospheres and/or different rates of heating with other samples of the same particulate material collected on other filters.

  3. Optical gyroscope

    NASA Astrophysics Data System (ADS)

    Seifollahi, Alireza

    It is said that future of the world is based on space exploration which leads us to think more about low cost and light weight instruments. Cheap and sensitive instruments should be de-signed and replace the expensive ones. One of the required instruments in space ships is gyroscope controls the direction of space ship. In this article I am going to give an idea to use optical properties in a new gyroscope which will be cheaper as well as more sensitive in com-pare with most of the being used normal gyroscope nowadays. This instrument uses an optical system to measure the angular changes in the direction of a space craft movements in any of the three axels. Any movement, even very small one, will move a crystal bulb which is lashed by some narrow elastic bands in a fixed box surrounded by three optical sources and light meters. Light meters measure the attitude and the angel of changes in the light beams going through the bulb which is related to the amount of changes in the space craft directions. The system will be very sensitive even against movement around its access. As an electro digital device in connection to a Main Process Unit (MPU) it can be used in Stability Augmentation System (SAS) in a space ship. The sensitivity rate of the instrument will be based on the quality and sensitivity of the light meters.

  4. Retinal Ganglion Cell Dysfunction in Asymptomatic G11778A: Leber Hereditary Optic Neuropathy

    PubMed Central

    Guy, John; Feuer, William J.; Porciatti, Vittorio; Schiffman, Joyce; Abukhalil, Fawzi; Vandenbroucke, Ruth; Rosa, Potyra R.; Lam, Byron L.

    2014-01-01

    Purpose. To report the serial evaluation of asymptomatic eyes of subjects with mutated G11778A mitochondrial DNA. Methods. Forty-five asymptomatic G11778A Leber hereditary optic neuropathy (LHON) carriers and two patients with the mutation who developed unilateral visual loss underwent testing that included visual acuity, automated visual field, pattern electroretinogram (PERG), and spectral-domain optical coherence tomography every 6 months between September 2008 and March 2012. Results. Visual acuity, visual fields, and retinal nerve fiber layer thickness remained stable within the normal range. Mean PERG amplitudes of carriers dropped progressively by ∼40% from baseline to 36 months. In addition, comparisons with the fellow eyes of patients with unilateral optic neuritis revealed a 3.4 ETDRS (Early Treatment Diabetic Retinopathy Study) letter loss in the LHON carriers. A single carrier developed visual loss, with PERG amplitudes dropping by half. In one of two LHON cases who presented with unilateral visual loss, visual acuity in the asymptomatic eye was ∼20/40 at baseline. The PERG amplitude of this eye was reduced to ∼30% of normal. Six months later, his visual acuity had dropped to ∼20/500. A second patient who was ∼20/20 and had a visual field defect in the asymptomatic eye at baseline remained at this level for the 18 months of follow-up. His PERG amplitudes were similar to those of asymptomatic carriers, with 0.78 μV at baseline that did not decline with follow-up. Conclusions. Declines of the PERG amplitude suggest subclinical retinal ganglion cell dysfunction in asymptomatic G11778A subjects, which is progressive. PMID:24398093

  5. Extrinsic Michelson interferometric fibre optic sensor with bend insensitive downlead

    NASA Astrophysics Data System (ADS)

    Hand, D. P.; Carolan, T. A.; Barton, J. S.; Jones, J. D. C.

    1993-04-01

    A novel optical arrangement is described for an interferometric optical fibre sensor of the extrinsic type. Based on a Michelson interferometer, it combines a bend insensitive downlead with the availability of antiphase outputs without insertion loss, and provides isolation of the source.

  6. Power optics

    SciTech Connect

    Apollonov, V V

    2014-02-28

    By using the theory we developed in the early 1970s, a broad range of phenomena is considered for an optical surface of a solid body that is exposed to radiation arbitrarily varying in time and producing temperature fields, thermoelastic stresses and thermal deformations on the surface layer. The examination is based on the relations (which are similar to Duhamel's integral formula from the theory of heat conduction) between the quantities characterising the thermal stress state in any nonstationary regimes of energy input into a solid. A peculiar feature of the analysis of the thermal stress state in this case consists in the fact that this relation comprises time as a parameter, which in turn is a consequence of incoherence of the quasi-stationary problem of thermoelasticity. This phenomenon is particularly important for the optics of high-power, high-pulse repetition rate lasers, which are being actively developed. In the review, we have recently published in Laser Physics, the thermal stress state of a solid is analysed. In this state, time is treated as an independent variable used in differentiation. Such an approach greatly reduces the applicability of the method. The review published contains data on the use of capillary porous structures made of various materials with different degrees of the surface development. Moreover, such structures can be efficiently employed to increase the heat exchange at a temperature below the boiling point of the coolant. In the present review we discuss the dependences of the limiting laser intensities on the duration of a pulse or a pulse train, corresponding to the three stages of the state of the reflecting surface and leading to unacceptable elastic deformations of the surface, to the plastic yield of the material accompanied by the formation of residual stresses and to the melting of the surface layer. We also analyse the problem of heat exchange in the surface layer with a liquid metal coolant pumped through it. The

  7. Parallel optical sampler

    DOEpatents

    Tauke-Pedretti, Anna; Skogen, Erik J; Vawter, Gregory A

    2014-05-20

    An optical sampler includes a first and second 1.times.n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCs convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.

  8. Optical beam jitter control

    NASA Astrophysics Data System (ADS)

    Watkins, R. Joseph; Chen, Hong-Jen; Agrawal, Brij N.; Shin, Young S.

    2004-06-01

    For several future imaging and communications spacecraft, a challenging area of technology development is the fine acquisition, tracking, and pointing (ATP) control of the spacecraft and its payload. For example, some spacecraft with large aperture(s) in the range of 10~30 m diameter requires a few arc-seconds accuracy, 10~15 nano-radians jitter, and a fast slewing rate to acquire the target. Furthermore these stringent requirements are at risk of great structure and control interactions. This paper we will focus on the control of optical beam jitter. A Laser Jitter Control (LJC) testbed has been constructed to test jitter algorithms. The testbed consists of two fast steering mirrors (FSM), three position sensing modules (PSM), one diode laser, and several beam splitters and mirrors, all on an isolated Newport optical bench. Jitter is injected with one FSM and the other FSM is used to control it. The jitter spectrum, representing the on-orbit spacecraft and beam jitter environment, contains not only narrow band noise due to rotating devices such as gyroscopes and reaction wheels but also broadband noise. The performance of a Wiener Filter-adaptive algorithm with ideal reference signal is established as the baseline for comparison of adaptive control methods in suppressing both broadband and narrowband disturbances. Specifically, the Least Mean Squares (LMS) approach and the Gradient Adaptive Lattice (GAL) approach are investigated during these experiments.

  9. Optical imaging of fast, dynamic neurophysiological function.

    SciTech Connect

    Rector, D. M.; Carter, K. M.; Yao, X.; George, J. S.

    2002-01-01

    Fast evoked responses were imaged from rat dorsal medulla and whisker barrel cortex. To investigate the biophysical mechanisms involved, fast optical responses associated with isolated crustacean nerve stimulation were recorded using birefringence and scattered light. Such studies allow optimization of non-invasive imaging techniques being developed for use in humans.

  10. All-Optical Fibre Networks For Coal Mines

    NASA Astrophysics Data System (ADS)

    Zientkiewicz, Jacek K.

    1987-09-01

    A topic of the paper is fiber-optic integrated network (FOIN) suited to the most hostile environments existing in coal mines. The use of optical fibres for transmission of mine instrumentation data offers the prospects of improved safety and immunity to electromagnetic interference (EMI). The feasibility of optically powered sensors has opened up new opportunities for research into optical signal processing architectures. This article discusses a new fibre-optic sensor network involving a time domain multiplexing(TDM)scheme and optical signal processing techniques. The pros and cons of different FOIN topologies with respect to coal mine applications are considered. The emphasis has been placed on a recently developed all-optical fibre network using spread spectrum code division multiple access (COMA) techniques. The all-optical networks have applications in explosive environments where electrical isolation is required.

  11. Quantum optics with interacting polaritons

    NASA Astrophysics Data System (ADS)

    Portolan, Stefano; Savasta, Salvatore

    The excitonic polariton concept was introduced already in 1958 by J. J. Hopfield. Although its description was based on a full quantum theory including light quantization, the investigations of the optical properties of excitons developed mainly independently of quantum optics. In this chapter we shall review exciton polariton quantum optical effects by means of some recent works and results that have appeared in the literature in both bulk semiconductors and in cavity embedded quantum wells. The first manifestation of excitonic quantum-optical coherent dynamics was observed experimentally 20 years later, in 1978, exploiting resonant hyper-parametric scattering. On the other hand, the possibility of generating entangled photon pairs by means of this resonant process was theoretically pointed out only lately in 1999, whereas the experimental evidence for the generation of ultraviolet polarization-entangled photon pairs by means of biexciton resonant parametric emission in a single crystal of semiconductor CuCl was reported only in 2004. The demonstrations of parametric amplification and parametric emission in semiconductor microcavities, together with the possibility of ultrafast optical manipulation and ease of integration of these micro-devices, have increased the interest in possible realization of nonclassical cavity-polariton states. In 2005 an experiment that probes polariton quantum correlations by exploiting quantum complementarity was proposed and realized. These results unequivocally proved that quantum optical effects at single photon level, arising from the interaction of light with electronic excitations of semiconductors and semiconductor nanostructures, were possible within these solid state systems, despite being far from isolated systems. The theoretical predictions that we review are based on a microscopic quantum theory of the nonlinear optical response of interacting electron systems relying on the dynamics controlled truncation scheme extended

  12. Dominant optic atrophy

    PubMed Central

    2012-01-01

    Definition of the disease Dominant Optic Atrophy (DOA) is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC) and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain. Epidemiology The prevalence of the disease varies from 1/10000 in Denmark due to a founder effect, to 1/30000 in the rest of the world. Clinical description DOA patients usually suffer of moderate visual loss, associated with central or paracentral visual field deficits and color vision defects. The severity of the disease is highly variable, the visual acuity ranging from normal to legal blindness. The ophthalmic examination discloses on fundoscopy isolated optic disc pallor or atrophy, related to the RGC death. About 20% of DOA patients harbour extraocular multi-systemic features, including neurosensory hearing loss, or less commonly chronic progressive external ophthalmoplegia, myopathy, peripheral neuropathy, multiple sclerosis-like illness, spastic paraplegia or cataracts. Aetiology Two genes (OPA1, OPA3) encoding inner mitochondrial membrane proteins and three loci (OPA4, OPA5, OPA8) are currently known for DOA. Additional loci and genes (OPA2, OPA6 and OPA7) are responsible for X-linked or recessive optic atrophy. All OPA genes yet identified encode mitochondrial proteins embedded in the inner membrane and ubiquitously expressed, as are the proteins mutated in the Leber Hereditary Optic Neuropathy. OPA1 mutations affect mitochondrial fusion, energy metabolism, control of apoptosis, calcium clearance and maintenance of mitochondrial genome integrity. OPA3 mutations only affect the energy metabolism and the control of apoptosis. Diagnosis Patients are usually diagnosed during their early childhood, because of bilateral, mild

  13. Multicolor filter all-garnet magneto-optical photonic crystals.

    PubMed

    Ansari, N; Khartsev, S I; Grishin, A M

    2012-09-01

    We demonstrate a multicolor optical filter and isolator based on a double-cavity magneto-optical (MO) photonic crystal. Being grown as a heteroepitaxial all-garnet multilayer, it compromises a strong MO response and high optical transmittance. Low-loss, high Faraday rotation passbands as well as strong light rejection within the stop band were achieved by optimization of distance between cavities and repetition number of distributed Bragg reflectors.

  14. Optical Limiting

    DTIC Science & Technology

    1992-05-22

    Organic Materials’, M.J. Soileau, T.H. Wei, M. Sheik- Bahae , D.J. Hagan, Martine Sence, and E.W. Van Stryland, I International Topical Meeting on Optics...Coulter and Joe Perry of the Jet Propulsion Laboratory for providing samples and their expertise on materials. I . M. Sheik- bahae , A.A. Said, and E.W...Form Approved AD A 5 1 INPAGE I OPml No. 0704-0188 lillill l I I ll (ll it1111 1 ~ ~ ae ’ Do e or .ewove. *MIraong the teffe ’Of re.-owng

  15. Optical Processing.

    DTIC Science & Technology

    1985-12-31

    34 Optics Letters, 2 (1), 1-3 (1978). 7. Grossberg, S., "Adaptive Resonance in Development, Perception and Cognition ," SIAM-AMS Proc., 13, 107-156...Illusions," Biol. Cybernetics, 23, 187-202, (1976b). 11. Grossberg, S., "How Does A Brain Build a Cognitive Code?", Psychol. Review, 87 (1), 1-51 (1980...34perceptron" (F. Rosenblatt, Principles of Neurodynamics ), workers in the neural network field have been seeking to understand how neural networks can perform

  16. Optical Couplers

    DTIC Science & Technology

    1975-12-01

    market . In general, the fiber diameter and cladding thickness choices that give the highest (best) packing fraction also give the highest (worst...57) Using Eqs (54) and (57). the worst case fractional power ratio for the radia.l data bus is R P* mLm *l£lfkIm^o 2N N-l (58) From...Galileo fiber optic bundles at the LED and de- tector interface, Eq (58) becomes where m, 1*6 .7 R mLm *T.6 TfkTfNao P* 16 (140) .75

  17. Optical devices

    DOEpatents

    Chaves, Julio C.; Falicoff, Waqidi; Minano, Juan C.; Benitez, Pablo; Dross, Oliver; Parkyn, Jr., William A.

    2010-07-13

    An optical manifold for efficiently combining a plurality of blue LED outputs to illuminate a phosphor for a single, substantially homogeneous output, in a small, cost-effective package. Embodiments are disclosed that use a single or multiple LEDs and a remote phosphor, and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. A further aperture mask is used to boost phosphor luminance with only modest loss of luminosity. Alternative non-recycling embodiments provide blue and yellow light in collimated beams, either separately or combined into white.

  18. Optical microphone

    DOEpatents

    Veligdan, James T.

    2000-01-11

    An optical microphone includes a laser and beam splitter cooperating therewith for splitting a laser beam into a reference beam and a signal beam. A reflecting sensor receives the signal beam and reflects it in a plurality of reflections through sound pressure waves. A photodetector receives both the reference beam and reflected signal beam for heterodyning thereof to produce an acoustic signal for the sound waves. The sound waves vary the local refractive index in the path of the signal beam which experiences a Doppler frequency shift directly analogous with the sound waves.

  19. Optical microfluidics

    SciTech Connect

    Kotz, K.T.; Noble, K.A.; Faris, G.W.

    2004-09-27

    We present a method for the control of small droplets based on the thermal Marangoni effect using laser heating. With this approach, droplets covering five orders of magnitude in volume ({approx}1.7 {mu}L to 14 pL), immersed in decanol, were moved on an unmodified polystyrene surface, with speeds of up to 3 mm/s. When two droplets were brought into contact, they spontaneously fused and rapidly mixed in less than 33 ms. This optically addressed microfluidic approach has many advantages for microfluidic transport, including exceptional reconfigurability, low intersample contamination, large volume range, extremely simple substrates, no electrical connections, and ready scaling to large arrays.

  20. Positive isolation disconnect

    NASA Technical Reports Server (NTRS)

    Rosener, A. A.; Jonkoniec, T. G.

    1975-01-01

    A positive isolation disconnect was developed for component replacement in serviced liquid and gaseous spacecraft systems. Initially a survey of feasible concepts was made to determine the optimum method for fluid isolation, sealing techniques, coupling concepts, and foolproofing techniques. The top concepts were then further evaluated, including the fabrication of a semifunctional model. After all tradeoff analyses were made, a final configuration was designed and fabricated for development testing. This resulted in a 6.35 mm (1/4 inch) line and 12.7 mm (1/2 inch) line positive isolation disconnect, each unit consisting of two coupled disconnect halves, each capable of fluid isolation with essentially zero clearance between them for zero leakage upon disconnect half disengagement. An interlocking foolproofing technique was incorporated that prevents uncoupling of disconnect halves prior to fluid isolation.

  1. EDITORIAL: Optical orientation Optical orientation

    NASA Astrophysics Data System (ADS)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  2. Optical diffractometry.

    PubMed

    Tavassoly, M Taghi; Amiri, Mohammad; Darudi, Ahmad; Aalipour, Rasoul; Saber, Ahad; Moradi, Ali-Reza

    2009-03-01

    Interference of light has numerous metrological applications because the optical path difference (OPD) can be varied at will between the interfering waves in the interferometers. We show how one can desirably change the optical path difference in diffraction. This leads to many novel and interesting metrological applications including high-precision measurements of displacement, phase change, refractive index profile, temperature gradient, diffusion coefficient, and coherence parameters, to name only a few. The subject fundamentally differs from interferometry in the sense that in the latter the measurement criterion is the change in intensity or fringe location, while in the former the criterion is the change in the visibility of fringes with an already known intensity profile. The visibility can vary from zero to one as the OPD changes by a half-wave. Therefore, measurements with the accuracy of a few nanometers are quite feasible. Also, the possibility of changing the OPD in diffraction allows us to use Fresnel diffraction in Fourier spectrometry, to enhance or suppress diffracted fields, and to build phase singularities that have many novel and useful applications.

  3. Optical scanner

    NASA Technical Reports Server (NTRS)

    Finkel, Mitchell W. (Inventor)

    1987-01-01

    An optical scanner for imaging lines in an object plane onto a linear array in a focal plane either continuously or discretely is described. The scanner consists of a set of four mutually perpendicularly oriented plane corner mirrors which provide a reflecting path that describes a parallelogram. In addition, there is a plane parallel scanning mirror with a front and back reflecting surface located midway between the first and fourth corner mirrors. It is oriented so that in the mid-scan position it is parallel to the first corner mirror, and therefore perpendicular to the fourth corner mirror. As the scan mirror rotates, rays incident from a plurality of lines in the object plane are selectively directed through the optical system arriving at a common intersection on the back surface of the scanning mirror where the rays are colinearly directed toward a lens and then imaged onto the linear array in the focal plane. A set of compensating mirrors may be introduced just before the imaging lens to compensate for a small and generally negligible path difference delta sub l between the axial and marginal rays.

  4. Optical Instruments

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Precision Lapping and Optical Co. has developed a wide variety of hollow retroreflector systems for applications involving the entire optical spectrum; they are, according to company literature, cheaper, more accurate, lighter and capable of greater size than solid prisms. Precision Lapping's major customers are aerospace and defense companies, government organizations, R&D and commercial instrument companies. For example, Precision Lapping supplies hollow retroreflectors for the laser fire control system of the Army's Abrams tank, and retroreflectors have been and are being used in a number of space tests relative to the Air Force's Strategic Defense Initiative research program. An example of a customer/user is Chesapeake Laser Systems, producer of the Laser Tracker System CMS-2000, which has applications in SDI research and industrial robotics. Another customer is MDA Scientific, Inc., manufacturer of a line of toxic gas detection systems used to monitor hazardous gases present in oil fields, refineries, offshore platforms, chemical plants, waste storage sites and other locations where gases are released into the environment.

  5. Optical Nanodozers

    NASA Astrophysics Data System (ADS)

    Khorshid, Ahmed; Reisner, Walter; Sakaue, Takahiro

    2015-03-01

    Experiment, simulation and scaling analytics are converging on a comprehensive picture regarding the equilibrium behaviour of nanochannel confined semiflexible, self-avoiding chains. Yet, strongly non-equilibrium behaviour of confined polymers is largely unexplored from either an experimental or theoretical point of view. Combining optical trapping and nanofluidics, we have developed a ``nanodozer'' assay for quantifying confined polymer dynamics. An optical trap is used to slide a nanosphere at a fixed velocity along a nanochannel. The trapped bead acts as a permeable gasket, letting fluid escape but preventing the polymer from passing. As the sliding bead comes in contact with a nanochannel extended DNA, the molecule is dynamically compressed, undergoing transient dynamics characterized by a traveling concentration ``shockwave'' before reaching a final steady state with a ramp-like concentration profile. Remarkably, these strongly non-equilibrium measurements can be quantified via a simple nonlinear convective-diffusion formalism and yield insights into the local blob statistics, allowing us to conclude that the compressed nanochannel confined chain exhibits mean-field behaviour.

  6. Laser window with annular grooves for thermal isolation

    DOEpatents

    Warner, B.E.; Horton, J.A.; Alger, T.W.

    1983-07-13

    A laser window or other optical element which is thermally loaded, heats up and causes optical distortions because of temperature gradients between the center and the edge. A number of annular grooves, one to three or more, are formed in the element between a central portion and edge portion, producing a web portion which concentrates the thermal gradient and thermally isolates the central portion from the edge portion, producing a uniform temperature profile across the central portion and therefore reduce the optical distortions. The grooves are narrow and closely spaced with respect to the thickness of the element, and successive grooves are formed from alternate sides of the element.

  7. Isolated adipic aciduria.

    PubMed

    Hasbini, D A; Mikati, M A; Habbal, Z M

    2001-01-01

    Adipic acid can appear, in combination with other dicarboxylic acids, in the urine of patients in a number of underlying metabolic diseases. A child with seizures and mental retardation of unknown etiology who was found to have elevated isolated adipic aciduria on investigation for metabolic diseases is reported. A dietary artifact was suspected, and the adipic aciduria resolved after the child was kept on a specific restricted diet for 3 days. This is the third report of isolated adipic aciduria secondary to food. Findings confirm the previous reports of dietary origin of isolated adipic aciduria and should alert clinicians to such artifact before committing patients to unnecessary treatments.

  8. Fault detection and isolation

    NASA Technical Reports Server (NTRS)

    Bernath, Greg

    1994-01-01

    In order for a current satellite-based navigation system (such as the Global Positioning System, GPS) to meet integrity requirements, there must be a way of detecting erroneous measurements, without help from outside the system. This process is called Fault Detection and Isolation (FDI). Fault detection requires at least one redundant measurement, and can be done with a parity space algorithm. The best way around the fault isolation problem is not necessarily isolating the bad measurement, but finding a new combination of measurements which excludes it.

  9. Isolation of Chlamydomonas Flagella

    PubMed Central

    Craige, Branch; Brown, Jason M.; Witman, George B.

    2014-01-01

    A simple, scalable, and fast procedure for the isolation of Chlamydomonas flagella is described. Chlamydomonas can be synchronously deflagellated by treatment with chemicals, pH shock, or mechanical shear. The Basic Protocol describes the procedure for flagellar isolation using dibucaine to induce flagellar abscission; we also describe the pH shock method as an Alternate Protocol when flagellar regeneration is desirable. Sub-fractionation of the isolated flagella into axonemes and the membrane + matrix fraction is described in a Support Protocol. PMID:23728744

  10. Graphene plasmons isolator based on non-reciprocal coupling.

    PubMed

    Zhu, Bofeng; Ren, Guobin; Gao, Yixiao; Wu, Beilei; Wang, Qiaoyi; Wan, Chenglong; Jian, Shuisheng

    2015-06-15

    In this paper we propose a graphene plasmons isolator based on non-reciprocal coupling within double graphene layer waveguide structure on a magneto-optical substrate. The difference in modal indices of graphene plasmons in opposite directions enables non-reciprocal coupling, which is theoretically investigated via coupled mode theory (CMT) and shows good agreement with numerical finite elements methods (FEM). The non-reciprocal coupling endows such system functionalities as magnetically controlled "plasmons circulator" or "plasmons isolator". For the latter case, systematical investigations of the insertion losses and isolation ratios with respect to the structural parameters, material properties, environmental parameters, fabrication errors as well as dielectric damping are presented. Theoretical investigation has shown an isolation ratio as 42 dB. The proposed plasmons circulator and isolator may serve as potential building blocks in graphene plasmons circuits.

  11. Integrated optics for fiber optic sensors

    NASA Technical Reports Server (NTRS)

    Minford, W. J.; Depaula, R. P.

    1991-01-01

    Recent progress achieved in the field of fiber-optic sensor applications is discussed with emphasis placed on LiNbO3-based integrated optics (IO). Particular consideration is given to advanced electromagnetic-field sensors, an integrated laser vibrometer system, and a fiber-optic gyroscope system. It is shown that the multifunction IO chips have enabled high perforamance fiber-optic sensors (e.g., fiber-optic gyros), provided advanced and unique signal processing capabilities and advanced architectures, and have a potential of making fiber-optic sensors at low cost.

  12. Single-cycle nonlinear optics

    SciTech Connect

    Max-Planck-Institut fur Quantenoptik; Goulielmakis, E.; Schultze, M.; Hofstetter, M.; Yakovlev, V. S.; Gagnon, J.; Uiberacker, M.; Aquila, A. L.; gullikson, E. M.; attwood, D. T.; Kienberger, R.; Krausz, F.; Kleineberg, U.

    2008-11-05

    Nonlinear optics plays a central role in the advancement of optical science and laser-based technologies. We report on the confinement of the nonlinear interaction of light with matter to a single wave cycle and demonstrate its utility for time-resolved and strong-field science. The electric field of 3.3-femtosecond, 0.72-micron laser pulses with a controlled and measured waveform ionizes atoms near the crests of the central wave cycle, with ionization being virtually switched off outside this interval. Isolated sub-100-attosecond pulses of extreme ultraviolet light (photon energy {approx} 80 electron volts), containing {approx} 0.5 nanojoule of energy, emerge from the interaction with a conversion efficiency of {approx} 10{sup -6}. These tools enable the study of the precision control of electron motion with light fields and electron-electron interactions with a resolution approaching the atomic unit of time ({approx} 24 attoseconds).

  13. Optical manifold

    DOEpatents

    Falicoff, Waqidi; Chaves, Julio C.; Minano, Juan Carlos; Benitez, Pablo; Dross, Oliver; Parkyn, Jr., William A.

    2010-02-23

    Optical systems are described that have at least one source of a beam of blue light with divergence under 15.degree.. A phosphor emits yellow light when excited by the blue light. A collimator is disposed with the phosphor and forms a yellow beam with divergence under 15.degree.. A dichroic filter is positioned to transmit the beam of blue light to the phosphor and to reflect the beam of yellow light to an exit aperture. In different embodiments, the beams of blue and yellow light are incident upon said filter with central angles of 15.degree., 22.degree., and 45.degree.. The filter may reflect all of one polarization and part of the other polarization, and a polarization rotating retroreflector may then be provided to return the unreflected light to the filter.

  14. Optical Tools

    NASA Astrophysics Data System (ADS)

    Roncali, E.; Tavitian, B.; Texier, I. E.; Peltié, P.; Perraut, F.; Boutet, J.; Cognet, L.; Lounis, B.; Marguet, D.; Thoumine, O.; Tramier, M.

    Fluorescence is a physical phenomenon described for the first time in 1852 by the British scientist George G. Stokes, famous for his work in mathematics and hydrodynamics. He observed the light emitted by a mineral after excitation (absorption of light by the mineral) by UV light. He then formulated what has become known as Stokes’ law, which says that the wavelength of fluorescence emission is longer than the excitation wavelength used to generate it. Some phenomena departing from this rule were later discovered, but do not in fact invalidate it. The possibility of visible excitation was subsequently developed, with the discovery of many fluorescing aromaticmolecules, called fluorophores. The identification of these compounds and improved control over the physical phenomenon meant that by 1930 research tools had been developed in biology, e.g., labeling certain tissues and bacteria so as to observe them by fluorescence. The optical microscope as it had existed since the nineteenth century thus gave rise to the fluorescence microscope: a reflection system to supply the light required to excite the fluorophores was added to the standard microscope, together with a suitable filtering system. Fluorescence microscopy soon became an important tool for biological analysis both in vitro and ex vivo, and other applications of light emission were also devised (light-emission phenomena of which fluorescence is a special case, described further in Sect. 7.2). It became possible to study phenomena that could not be observed by standard optical microscopy. Among other things, the location of molecules inside cells, monitoring of intracellular processes, and detection of single molecules all become feasible by means of fluorescence microscopy.

  15. Fiber-optic technology review

    SciTech Connect

    Lyons, P.B.

    1980-01-01

    A history of fiber technology is presented. The advantages of fiber optics are discussed (bandwidth, cost, weight and size, nonmetallic construction and isolation). Some aspects of the disadvantages of fiber systems briefly discussed are fiber and cable availability, fiber components, radiation effects, receivers and transmitters, and material dispersion. Particular emphasis over the next several years will involve development of fibers and systems optimized for use at wavelengths near 1.3 ..mu..m and development of wavelengths multiplexers for simultaneous system operation at several wavelengths.

  16. Development of plasmonic isolator for integration into photonic integrated circuits (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Zayets, Vadym; Saito, Hidekazu; Ando, Koji; Yuasa, Shinji

    2015-09-01

    An optical isolator is an important component of an optical network. At present, there is a significant commercial demand for an optical isolator, which can be integrated into the Photonic Integrated Circuits (PIC). A new design of an integrated optical isolator, which utilizes unique non-reciprocal properties of surface plasmons, has been proposed [1]. The main obstacle for a practical realization of the proposed design is a substantial propagation loss of the surface plasmons in structures containing a ferromagnetic metal. The reduction of the propagation loss of a surface plasmon is the key to make the plasmonic isolator competitive with other designs of the integrated isolator. We studied experimentally optical and magneto-optical properties of a Fe plasmonic waveguide integrated with an AlGaAs rib waveguides and a Co plasmonic waveguide integrated with Si nanowire waveguides. It was demonstrated experimentally that by utilizing a double-dielectric plasmonic waveguide it is possible to reduce significantly the optical loss in a plasmonic waveguide. For Fe/SiO2/AlGaAs double-dielectric plasmonic waveguide the low optical loss of 0.03 dB/um is obtained. As far as we know at present it is a lowest optical loss demonstrated for a plasmon propagating at a surface of a ferromagnetic metal. For Co/Ti2O3/SiO2 double-dielectric plasmonic waveguide integrated with a Si nanowire waveguide on a Si substrate the optical loss of 0.7 dB/um was demonstrated. The designs of the plasmonic isolator utilizing a ring resonator or a non-reciprocal coupler were studied. [1] V. Zayets, H. Saito, S. Yuasa, and K. Ando,, Materials 5, 857 (2012).

  17. Base isolation: Fresh insight

    SciTech Connect

    Shustov, V.

    1993-07-15

    The objective of the research is a further development of the engineering concept of seismic isolation. Neglecting the transient stage of seismic loading results in a widespread misjudgement: The force of resistance associated with velocity is mostly conceived as a source of damping vibrations, though it is an active force at the same time, during an earthquake type excitation. For very pliant systems such as base isolated structures with relatively low bearing stiffness and with artificially added heavy damping mechanism, the so called `damping`` force may occur even the main pushing force at an earthquake. Thus, one of the two basic pillars of the common seismic isolation philosophy, namely, the doctrine of usefulness and necessity of a strong damping mechanism, is turning out to be a self-deception, sometimes even jeopardizing the safety of structures and discrediting the very idea of seismic isolation. There is a way out: breaking with damping dependancy.

  18. Four-Channel Threshold Detector With Optical Isolation

    DTIC Science & Technology

    2009-02-01

    Metal Film Resistor 1 1 N4733 5.1 V Zenor Diode 2 2N3904w General Purpose NPN Transistor 2 OMISS2 12D 12V DPDT Relay 1 Table C-2. The two...are controlled from the relay board’s control transistor (Q2). 2. Theory of Operation The threshold detector consists of two different electronics...the comparators indicates either a failure or an exceeded threshold. The complementary metal oxide semiconducting field-effect transistor (CMOS) AND

  19. Single-cycle Optical Pulses and Isolated Attosecond Pulse Generation

    DTIC Science & Technology

    2012-02-29

    picosecond green light from a frequency-doubled hybrid cryogenic Yb:YAG laser system,” 36 UFO /HFSW 2009 (Arcachon, France, Aug. 31-Sept. 4, 2009...High Fields Short Wavelength,” ( UFO VII – HFSW XIII), Arcachon, France, August 31 – September 4, 2009 (invited). 25) Kyung-Han Hong, Juliet Gopinath

  20. Isolated sleep paralysis.

    PubMed

    Sawant, Neena S; Parkar, Shubhangi R; Tambe, Ravindra

    2005-10-01

    Sleep paralysis (SP) is a cardinal symptom of narcolepsy. However, little is available in the literature about isolated sleep paralysis. This report discusses the case of a patient with isolated sleep paralysis who progressed from mild to severe SP over 8 years. He also restarted drinking alcohol to be able to fall asleep and allay his anxiety symptoms. The patient was taught relaxation techniques and he showed complete remission of the symptoms of SP on follow up after 8 months.

  1. Optical path switching based differential absorption radiometry for substance detection

    NASA Technical Reports Server (NTRS)

    Sachse, Glen W. (Inventor)

    2005-01-01

    An optical path switch divides sample path radiation into a time series of alternating first polarized components and second polarized components. The first polarized components are transmitted along a first optical path and the second polarized components along a second optical path. A first gasless optical filter train filters the first polarized components to isolate at least a first wavelength band thereby generating first filtered radiation. A second gasless optical filter train filters the second polarized components to isolate at least a second wavelength band thereby generating second filtered radiation. A beam combiner combines the first and second filtered radiation to form a combined beam of radiation. A detector is disposed to monitor magnitude of at least a portion of the combined beam alternately at the first wavelength band and the second wavelength band as an indication of the concentration of the substance in the sample path.

  2. Optical path switching based differential absorption radiometry for substance detection

    NASA Technical Reports Server (NTRS)

    Sachse, Glen W. (Inventor)

    2003-01-01

    An optical path switch divides sample path radiation into a time series of alternating first polarized components and second polarized components. The first polarized components are transmitted along a first optical path and the second polarized components along a second optical path. A first gasless optical filter train filters the first polarized components to isolate at least a first wavelength band thereby generating first filtered radiation. A second gasless optical filter train filters the second polarized components to isolate at least a second wavelength band thereby generating second filtered radiation. A beam combiner combines the first and second filtered radiation to form a combined beam of radiation. A detector is disposed to monitor magnitude of at least a portion of the combined beam alternately at the first wavelength band and the second wavelength band as an indication of the concentration of the substance in the sample path.

  3. Optical data latch

    DOEpatents

    Vawter, G. Allen

    2010-08-31

    An optical data latch is formed on a substrate from a pair of optical logic gates in a cross-coupled arrangement in which optical waveguides are used to couple an output of each gate to an photodetector input of the other gate. This provides an optical bi-stability which can be used to store a bit of optical information in the latch. Each optical logic gate, which can be an optical NOT gate (i.e. an optical inverter) or an optical NOR gate, includes a waveguide photodetector electrically connected in series with a waveguide electroabsorption modulator. The optical data latch can be formed on a III-V compound semiconductor substrate (e.g. an InP or GaAs substrate) from III-V compound semiconductor layers. A number of optical data latches can be cascaded to form a clocked optical data shift register.

  4. Optics at westinghouse.

    PubMed

    Ivey, H F

    1972-05-01

    Past and present work in optics at the Westinghouse Electric Corporation is surveyed. The areas discussed include lamps and illumination, industrial optical applications, television and imaging systems, and lasers and coherent optics.

  5. Fiber optic multiplex optical transmission system

    NASA Technical Reports Server (NTRS)

    Bell, C. H. (Inventor)

    1977-01-01

    A multiplex optical transmission system which minimizes external interference while simultaneously receiving and transmitting video, digital data, and audio signals is described. Signals are received into subgroup mixers for blocking into respective frequency ranges. The outputs of these mixers are in turn fed to a master mixer which produces a composite electrical signal. An optical transmitter connected to the master mixer converts the composite signal into an optical signal and transmits it over a fiber optic cable to an optical receiver which receives the signal and converts it back to a composite electrical signal. A de-multiplexer is coupled to the output of the receiver for separating the composite signal back into composite video, digital data, and audio signals. A programmable optic patch board is interposed in the fiber optic cables for selectively connecting the optical signals to various receivers and transmitters.

  6. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  7. Integrated optics technology study

    NASA Technical Reports Server (NTRS)

    Chen, B.; Findakly, T.; Innarella, R.

    1982-01-01

    The status and near term potential of materials and processes available for the fabrication of single mode integrated electro-optical components are discussed. Issues discussed are host material and orientation, waveguide formation, optical loss mechanisms, wavelength selection, polarization effects and control, laser to integrated optics coupling fiber optic waveguides to integrated optics coupling, sources, and detectors. Recommendations of the best materials, technology, and processes for fabrication of integrated optical components for communications and fiber gyro applications are given.

  8. Determination of motility forces on isolated chromosomes with laser tweezers.

    PubMed

    Khatibzadeh, Nima; Stilgoe, Alexander B; Bui, Ann A M; Rocha, Yesenia; Cruz, Gladys M; Loke, Vince; Shi, Linda Z; Nieminen, Timo A; Rubinsztein-Dunlop, Halina; Berns, Michael W

    2014-10-31

    Quantitative determination of the motility forces of chromosomes during cell division is fundamental to understanding a process that is universal among eukaryotic organisms. Using an optical tweezers system, isolated mammalian chromosomes were held in a 1064 nm laser trap. The minimum force required to move a single chromosome was determined to be ≈ 0.8-5 pN. The maximum transverse trapping efficiency of the isolated chromosomes was calculated as ≈ 0.01-0.02. These results confirm theoretical force calculations of ≈ 0.1-12 pN to move a chromosome on the mitotic or meiotic spindle. The verification of these results was carried out by calibration of the optical tweezers when trapping microspheres with a diameter of 4.5-15 µm in media with 1-7 cP viscosity. The results of the chromosome and microsphere trapping experiments agree with optical models developed to simulate trapping of cylindrical and spherical specimens.

  9. Faraday isolator stably operating in a wide temperature range

    NASA Astrophysics Data System (ADS)

    Mironov, E. A.; Voitovich, A. V.; Palashov, O. V.

    2016-03-01

    A method of stabilizing Faraday isolator characteristics at varying temperatures is proposed in this letter. The method is based on the use of a magnetic system with an inhomogeneous magnetic field and a magneto-optical element holder made of a material with a high value of thermal expansion coefficient. Changing the rotation angle of the polarization plane of radiation caused by the temperature variation of the magneto-optical element and the temperature dependence of its Verdet constant is compensated by its shifting in the magnetic field. The developed device demonstrates an isolation ratio of more than 40 dB at a temperature range of 25 °C. Estimates show the possibility of providing an isolation ratio of more than 45 dB in a temperature range of 60 °C.

  10. Staphylococcal micrococcins. II. Isolation, purification and identification.

    PubMed

    Breiter, J; Metz, H; Grigo, J

    1975-08-01

    Seven strains belonging to the Micrococcaceae family and excreting substances with antibiotic activity, were grown in submerged cultures on technical scale for isolation, purification and identification of biologically active compounds. Two basic substances were isolated and classified to the micrococcin antibiotics family. The naturally occurring mixture of micrococcin M1 and M3 was called micrococcin M. This antibiotic has the formula C48H50O11N12S6 and a molecular weight of about 1160, melting point 221--224 degrees C, and optical rotation [a]20/D = + 66.6. Other antibiotically active substances produced by seven investigated strains were identified as micrococcin M or as separate compounds. Comparison with previously described micrococcin and micrococcin P has been made.

  11. Optic Nerve Decompression

    MedlinePlus

    ... Nerve Decompression Dacryocystorhinostomy (DCR) Disclosure Statement Printer Friendly Optic Nerve Decompression John Lee, MD Introduction Optic nerve decompression is a surgical procedure aimed at ...

  12. Fiber optic monitoring device

    DOEpatents

    Samborsky, J.K.

    1993-10-05

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information. 4 figures.

  13. Optical Beam Control Using Adaptive Optics

    DTIC Science & Technology

    2005-12-01

    30 1. Principles of Operation......................................................................31 VI. USING ZERNIKE POLYNOMIALS TO...help patience in helping me to understand the underlying principles of optics. xiv THIS PAGE INTENTIONALLY...correct this using adaptive optics. Adaptive Optics first got its start in 215 AD with the destruction of the Roman Fleet by Archimedes (Lamberson

  14. Optical-to-optical interface device

    NASA Technical Reports Server (NTRS)

    Jacobson, A. D.; Bleha, W. P.; Miller, L.; Grinberg, J.; Fraas, L.; Margerum, D.

    1975-01-01

    An investigation was conducted to develop an optical-to-optical interface device capable of performing real-time incoherent-to-incoherent optical image conversion. The photoactivated liquid crystal light valve developed earlier represented a prototype liquid crystal light valve device capable of performing these functions. A device was developed which had high performance and extended lifetime.

  15. Polarization-independent all-fiber isolator based on asymmetric fiber tapers.

    PubMed

    Fang, X

    1996-11-01

    Nonreciprocal intensity transmission in optical fibers can be realized by use of an asymmetric fiber taper. A few-mode fiber taper-based nonreciprocal component is designed, and its nonreciprocal transmission characteristics are demonstrated. This structure can be employed to build polarization-independent all-fiber isolators or fiber-optic sensors.

  16. Electromechanical lever blocks for active vibration isolation

    NASA Astrophysics Data System (ADS)

    Zago, Lorenzo; Genequand, Pierre M.

    2000-04-01

    This paper is a follow-up of a presentation at the Smart Structures Symposium of 1998. There we described an innovative technical solution which provides a combined passive damping and isolation interface with the appropriate transmissibility characteristics between a vibrating base and a sensitive payload, typically an optical terminal/telescope. The particularity of the solution is primarily found in the implementation of energy dissipation by means linear electromagnetic linear motors leveraged by means of flexure elements, to constitute an integrated resistor-damped electromechanic lever block, which we called MEDI (Mechanical Elastic element for Damping and Isolation). Passive viscous damping with attenuation of the order of -20 dB at 50 Hz with respect to a hard fixation, is obtained by simply short- circuiting the electro-magnetic motor. The study and test program presented here extends the application of MEDIs to active vibration reduction systems. The study, contracted by the European Space Agency, aimed at investigating the possibility of using the MEDI as an active isolator for scientific experiments in the International Space Station. By controlling the current in the electromagnetic motor in closed loop with the signal from specially designed force sensor (with extremely low noise), we achieved attenuation of the order of -15 dB at 1 Hz, -30 dB at 10 Hz, -50 dB at 30 Hz, with the isolation slope starting as low as 0.1 Hz.

  17. Astrometric Telescope Facility isolation and pointing study

    NASA Technical Reports Server (NTRS)

    Hibble, William; Allen, Terry; Jackson, Louis; Medbery, James; Self, Richard

    1988-01-01

    The Astrometric Telescope Facility (ATF), an optical telescope designed to detect extrasolar planetary systems, is scheduled to be a major user of the Space Station's Payload Pointing System (PPS). However, because the ATF has such a stringent pointing stability specification and requires + or - 180 deg roll about its line of sight, mechanisms to enhance the basic PPS capability are required. The ATF pointing performance achievable by the addition of a magnetic isolation and pointing system (MIPS) between the PPS upper gimbal and the ATF, and separately, by the addition of a passive isolation system between the Space Station and the PPS base was investigated. The candidate MIPS can meet the ATF requirements in the presence of a 0.01 g disturbance. It fits within the available annular region between the PPS and the ATF while meeting power and weight limitations and providing the required roll motion, payload data and power services. By contrast, the passive base isolator system must have an unrealistically low isolation bandwidth on all axes to meet ATF pointing requirements and does not provide roll about the line of sight.

  18. Illusion optics

    NASA Astrophysics Data System (ADS)

    Lai, Yun; Ng, Jack; Chen, Huan-Yang; Zhang, Zhao-Qing; Chan, C. T.

    2010-09-01

    The technique of “transformation optics” establishes a correspondence between coordinate transformation and material constitutive parameters. Most of the transformation optics mappings give metamaterials that have graded positive refractive indices that can steer light in curves defined by the coordinate transformation. We will focus on those “folded-geometry mappings” that give negative refractive index materials that have special wave scattering properties. One interesting example is a kind of remote illusion device that can transform the stereoscopic image of an object into the illusion of some other object of our choice. The conceptual device can create the illusion without touching or encircling the object. For any incident wave, the device transforms the scattered waves of the original object into that of the object chosen for illusion outside a virtual boundary. We will illustrate some possible applications of this type of metamaterial remote device, including “cloaking at a distance,” partial cloaking, cloaking from an embedded device, revealing a hidden object inside a container, turning the image of one object into that of another object, and seeing through a wall. The feasibility of building this remote illusion device by metamaterials will also be discussed.

  19. CCAT optics

    NASA Astrophysics Data System (ADS)

    Padin, S.; Hollister, M.; Radford, S.; Sayers, J.; Woody, D.; Zmuidzinas, J.; Cortes-Medellin, G.; Sebring, T.; Stacey, G.

    2010-07-01

    CCAT will be a 25 m diameter, submillimeter-wave telescope. It will be located on Cerro Chajnantor in the Atacama Desert, near ALMA. CCAT will be an on-axis, Ritchey-Chrétien design with an active primary to compensate gravitational deformations. The primary mirror will have 162 segments, each with ~0.5 × 0.5 m reflecting tiles on a ~2×2 m, insulated, carbon-fiber-reinforced-plastic subframe. CCAT will be equipped with wide-field, multi-color cameras and multi-object spectrometers at its Nasmyth foci. These instruments will cover all the atmospheric windows in the λ = 0.2 to 2 mm range. The field of view at the Nasmyth foci will be 1°, so CCAT will be able to support cameras with a few ×104 detectors (spaced 2 beamwidths) at λ = 1 mm to a few ×106 detectors (spaced half a beamwidth) at λ = 350 μm. Single instruments of this size are probably impractical, so we will break the field into smaller pieces, with a separate sub-field camera for each piece. The cameras will require some relay optics to couple the fairly slow beam from the telescope to the detectors. A reflective relay for 1° field of view is too large to be practical, so we plan to use a compact, cold, refractive relay in each sub-field camera.

  20. Optical NAND gate

    DOEpatents

    Skogen, Erik J.; Raring, James; Tauke-Pedretti, Anna

    2011-08-09

    An optical NAND gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator and a photodetector. One pair of the optical waveguide devices is electrically connected in parallel to operate as an optical AND gate; and the other pair of the optical waveguide devices is connected in series to operate as an optical NOT gate (i.e. an optical inverter). The optical NAND gate utilizes two digital optical inputs and a continuous light input to provide a NAND function output. The optical NAND gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.