Transient downregulation of Sema3A mRNA in a rat model for temporal lobe epilepsy. A novel molecular event potentially contributing to mossy fiber sprouting

NARCIS (Netherlands)

Holtmaat, Anthony J D G; Gorter, Jan A; de Wit, Joris; Tolner, Else A; Spijker, Sabine; Giger, Roman J; Lopes da Silva, Fernando H; Verhaagen, J.

Mossy fiber sprouting (MFS) in the hippocampal dentate gyrus is thought to play a critical role in the hyperexcitability of the hippocampus in temporal lobe epilepsy patients. The composition of molecular signals that is needed to direct this sprouting response has not yet been elucidated to a great

NeuroD2 regulates the development of hippocampal mossy fiber synapses

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Wilke Scott A

2012-02-01

Full Text Available Abstract Background The assembly of neural circuits requires the concerted action of both genetically determined and activity-dependent mechanisms. Calcium-regulated transcription may link these processes, but the influence of specific transcription factors on the differentiation of synapse-specific properties is poorly understood. Here we characterize the influence of NeuroD2, a calcium-dependent transcription factor, in regulating the structural and functional maturation of the hippocampal mossy fiber (MF synapse. Results Using NeuroD2 null mice and in vivo lentivirus-mediated gene knockdown, we demonstrate a critical role for NeuroD2 in the formation of CA3 dendritic spines receiving MF inputs. We also use electrophysiological recordings from CA3 neurons while stimulating MF axons to show that NeuroD2 regulates the differentiation of functional properties at the MF synapse. Finally, we find that NeuroD2 regulates PSD95 expression in hippocampal neurons and that PSD95 loss of function in vivo reproduces CA3 neuron spine defects observed in NeuroD2 null mice. Conclusion These experiments identify NeuroD2 as a key transcription factor that regulates the structural and functional differentiation of MF synapses in vivo.

Hilar mossy cell circuitry controlling dentate granule cell excitability

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Seiichiro eJinde

2013-02-01

Full Text Available Glutamatergic hilar mossy cells of the dentate gyrus can either excite or inhibit distant granule cells, depending on whether their direct excitatory projections to granule cells or their projections to local inhibitory interneurons dominate. However, it remains controversial whether the net effect of mossy cell loss is granule cell excitation or inhibition. Clarifying this controversy has particular relevance to temporal lobe epilepsy, which is marked by dentate granule cell hyperexcitability and extensive loss of dentate hilar mossy cells. Two diametrically opposed hypotheses have been advanced to explain this granule cell hyperexcitability – the dormant basket cell and the irritable mossy cell hypotheses. The dormant basket cell hypothesis proposes that mossy cells normally exert a net inhibitory effect on granule cells and therefore their loss causes dentate granule cell hyperexcitability. The irritable mossy cell hypothesis takes the opposite view that mossy cells normally excite granule cells and that the surviving mossy cells in epilepsy increase their activity, causing granule cell excitation. The inability to eliminate mossy cells selectively has made it difficult to test these two opposing hypotheses. To this end, we developed a transgenic toxin-mediated, mossy cell-ablation mouse line. Using these mutants, we demonstrated that the extensive elimination of hilar mossy cells causes granule cell hyperexcitability, although the mossy cell loss observed appeared insufficient to cause clinical epilepsy. In this review, we focus on this topic and also suggest that different interneuron populations may mediate mossy cell-induced translamellar lateral inhibition and intralamellar recurrent inhibition. These unique local circuits in the dentate hilar region may be centrally involved in the functional organization of the dentate gyrus.

Zinc-mediated transactivation of TrkB potentiates the hippocampal mossy fiber-CA3 pyramid synapse.

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Huang, Yang Z; Pan, Enhui; Xiong, Zhi-Qi; McNamara, James O

2008-02-28

The receptor tyrosine kinase, TrkB, is critical to diverse functions of the mammalian nervous system in health and disease. Evidence of TrkB activation during epileptogenesis in vivo despite genetic deletion of its prototypic neurotrophin ligands led us to hypothesize that a non-neurotrophin, the divalent cation zinc, can transactivate TrkB. We found that zinc activates TrkB through increasing Src family kinase activity by an activity-regulated mechanism independent of neurotrophins. One subcellular locale at which zinc activates TrkB is the postsynaptic density of excitatory synapses. Exogenous zinc potentiates the efficacy of the hippocampal mossy fiber (mf)-CA3 pyramid synapse by a TrkB-requiring mechanism. Long-term potentiation of this synapse is impaired by deletion of TrkB, inhibition of TrkB kinase activity, and by CaEDTA, a selective chelator of zinc. The activity-dependent activation of synaptic TrkB in a neurotrophin-independent manner provides a mechanism by which this receptor can regulate synaptic plasticity.

Neuroprotective Effect of Uncaria rhynchophylla in Kainic Acid-Induced Epileptic Seizures by Modulating Hippocampal Mossy Fiber Sprouting, Neuron Survival, Astrocyte Proliferation, and S100B Expression

OpenAIRE

Chung-Hsiang Liu; Yi-Wen Lin; Nou-Ying Tang; Hsu-Jan Liu; Ching-Liang Hsieh

2012-01-01

Uncaria rhynchophylla (UR), which is a traditional Chinese medicine, has anticonvulsive effect in our previous studies, and the cellular mechanisms behind this are still little known. Because of this, we wanted to determine the importance of the role of UR on kainic acid- (KA-) induced epilepsy. Oral UR for 6 weeks can successfully attenuate the onset of epileptic seizure in animal tests. Hippocampal mossy fiber sprouting dramatically decreased, while neuronal survival increased with UR treat...

Hilar mossy cells of the dentate gyrus: a historical perspective

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Helen E Scharfman

2013-01-01

Full Text Available The circuitry of the dentate gyrus of the hippocampus is unique compared to other hippocampal subfields because there are two glutamatergic principal cells instead of one: granule cells, which are the vast majority of the cells in the dentate gyrus, and the so-called ‘mossy cells.’ The distinctive appearance of mossy cells, the extensive divergence of their axons, and their vulnerability to excitotoxicity relative to granule cells has led to a great deal of interest in mossy cells. Nevertheless, there is no consensus about the normal functions of mossy cells and the implications of their vulnerability. There even seems to be some ambiguity about exactly what mossy cells are. Here we review initial studies of mossy cells, characteristics that define them, and suggest a practical definition to allow investigators to distinguish mossy cells from other hilar neurons even if all morphological and physiological information is unavailable due to technical limitations of their experiments. In addition, hypotheses are discussed about the role of mossy cells in the dentate gyrus network, reasons for their vulnerability and their implications for disease.

Hilar mossy cells of the dentate gyrus: a historical perspective

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Scharfman, Helen E.; Myers, Catherine E.

2013-01-01

The circuitry of the dentate gyrus (DG) of the hippocampus is unique compared to other hippocampal subfields because there are two glutamatergic principal cells instead of one: granule cells, which are the vast majority of the cells in the DG, and the so-called “mossy cells.” The distinctive appearance of mossy cells, the extensive divergence of their axons, and their vulnerability to excitotoxicity relative to granule cells has led to a great deal of interest in mossy cells. Nevertheless, there is no consensus about the normal functions of mossy cells and the implications of their vulnerability. There even seems to be some ambiguity about exactly what mossy cells are. Here we review initial studies of mossy cells, characteristics that define them, and suggest a practical definition to allow investigators to distinguish mossy cells from other hilar neurons even if all morphological and physiological information is unavailable due to technical limitations of their experiments. In addition, hypotheses are discussed about the role of mossy cells in the DG network, reasons for their vulnerability and their implications for disease. PMID:23420672

Npas4 Is a Critical Regulator of Learning-Induced Plasticity at Mossy Fiber-CA3 Synapses during Contextual Memory Formation

DEFF Research Database (Denmark)

Weng, Feng-Ju; Garcia, Rodrigo I; Lutzu, Stefano

2018-01-01

Synaptic connections between hippocampal mossy fibers (MFs) and CA3 pyramidal neurons are essential for contextual memory encoding, but the molecular mechanisms regulating MF-CA3 synapses during memory formation and the exact nature of this regulation are poorly understood. Here we report...... pyramidal cells that were activated by contextual learning and found that MF inputs on these cells were selectively strengthened. Deletion of Npas4 prevented both contextual memory formation and this learning-induced synaptic modification. We further show that Npas4 regulates MF-CA3 synapses by controlling...... the expression of the polo-like kinase Plk2. Thus, Npas4 is a critical regulator of experience-dependent, structural, and functional plasticity at MF-CA3 synapses during contextual memory formation....

Mossy cells in epilepsy: rigor mortis or vigor mortis?

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Ratzliff, Annad d H; Santhakumar, Vijayalakshmi; Howard, Allyson; Soltesz, Ivan

2002-03-01

Mossy cells are bi-directionally connected through a positive feedback loop to granule cells, the principal cells of the dentate gyrus. This recurrent circuit is strategically placed between the entorhinal cortex and the hippocampal CA3 region. In spite of their potentially pro-convulsive arrangement with granule cells, mossy cells have not been seriously considered to promote seizures, because mossy cells, allegedly one of the most vulnerable cell types in the entire mammalian brain, have long been 'known' to die en masse in epilepsy. However, new data suggest that rumors of the rapid demise of the mossy cells might have been greatly exaggerated.

A Combined Optogenetic-Knockdown Strategy Reveals a Major Role of Tomosyn in Mossy Fiber Synaptic Plasticity

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Yoav Ben-Simon

2015-07-01

Full Text Available Neurotransmitter release probability (Pr largely determines the dynamic properties of synapses. While much is known about the role of presynaptic proteins in transmitter release, their specific contribution to synaptic plasticity is unclear. One such protein, tomosyn, is believed to reduce Pr by interfering with the SNARE complex formation. Tomosyn is enriched at hippocampal mossy fiber-to-CA3 pyramidal cell synapses (MF-CA3, which characteristically exhibit low Pr, strong synaptic facilitation, and pre-synaptic protein kinase A (PKA-dependent long-term potentiation (LTP. To evaluate tomosyn’s role in MF-CA3 function, we used a combined knockdown (KD-optogenetic strategy whereby presynaptic neurons with reduced tomosyn levels were selectively activated by light. Using this approach in mouse hippocampal slices, we found that facilitation, LTP, and PKA-induced potentiation were significantly impaired at tomosyn-deficient synapses. These findings not only indicate that tomosyn is a key regulator of MF-CA3 plasticity but also highlight the power of a combined KD-optogenetic approach to determine the role of presynaptic proteins.

Specific Disruption of Hippocampal Mossy Fiber Synapses in a Mouse Model of Familial Alzheimer's Disease

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Wilke, Scott A.; Raam, Tara; Antonios, Joseph K.; Bushong, Eric A.; Koo, Edward H.; Ellisman, Mark H.; Ghosh, Anirvan

2014-01-01

The earliest stages of Alzheimer's disease (AD) are characterized by deficits in memory and cognition indicating hippocampal pathology. While it is now recognized that synapse dysfunction precedes the hallmark pathological findings of AD, it is unclear if specific hippocampal synapses are particularly vulnerable. Since the mossy fiber (MF) synapse between dentate gyrus (DG) and CA3 regions underlies critical functions disrupted in AD, we utilized serial block-face electron microscopy (SBEM) to analyze MF microcircuitry in a mouse model of familial Alzheimer's disease (FAD). FAD mutant MF terminal complexes were severely disrupted compared to control – they were smaller, contacted fewer postsynaptic spines and had greater numbers of presynaptic filopodial processes. Multi-headed CA3 dendritic spines in the FAD mutant condition were reduced in complexity and had significantly smaller sites of synaptic contact. Significantly, there was no change in the volume of classical dendritic spines at neighboring inputs to CA3 neurons suggesting input-specific defects in the early course of AD related pathology. These data indicate a specific vulnerability of the DG-CA3 network in AD pathogenesis and demonstrate the utility of SBEM to assess circuit specific alterations in mouse models of human disease. PMID:24454724

Aging-related impairments of hippocampal mossy fibers synapses on CA3 pyramidal cells.

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Villanueva-Castillo, Cindy; Tecuatl, Carolina; Herrera-López, Gabriel; Galván, Emilio J

2017-01-01

The network interaction between the dentate gyrus and area CA3 of the hippocampus is responsible for pattern separation, a process that underlies the formation of new memories, and which is naturally diminished in the aged brain. At the cellular level, aging is accompanied by a progression of biochemical modifications that ultimately affects its ability to generate and consolidate long-term potentiation. Although the synapse between dentate gyrus via the mossy fibers (MFs) onto CA3 neurons has been subject of extensive studies, the question of how aging affects the MF-CA3 synapse is still unsolved. Extracellular and whole-cell recordings from acute hippocampal slices of aged Wistar rats (34 ± 2 months old) show that aging is accompanied by a reduction in the interneuron-mediated inhibitory mechanisms of area CA3. Several MF-mediated forms of short-term plasticity, MF long-term potentiation and at least one of the critical signaling cascades necessary for potentiation are also compromised in the aged brain. An analysis of the spontaneous glutamatergic and gamma-aminobutyric acid-mediated currents on CA3 cells reveal a dramatic alteration in amplitude and frequency of the nonevoked events. CA3 cells also exhibited increased intrinsic excitability. Together, these results demonstrate that aging is accompanied by a decrease in the GABAergic inhibition, reduced expression of short- and long-term forms of synaptic plasticity, and increased intrinsic excitability. Copyright © 2016 Elsevier Inc. All rights reserved.

Spontaneous release from mossy fiber terminals inhibits Ni2+-sensitive T-type Ca2+ channels of CA3 pyramidal neurons in the rat organotypic hippocampal slice.

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Reid, Christopher A; Xu, Shenghong; Williams, David A

2008-01-01

Mossy fibers (axons arising from dentate granule cells) form large synaptic contacts exclusively onto the proximal apical dendrites of CA3 pyramidal neurons. They can generate large synaptic currents that occur in close proximity to the soma. These properties mean that active conductance in the proximal apical dendrite could have a disproportionate influence on CA3 pyramidal neuron excitability. Ni(2+)-sensitive T-type Ca(2+) channels are important modulators of dendritic excitability. Here, we use an optical approach to determine the contribution of Ni(2+) (100 microM)-sensitive Ca(2+) channels to action potential (AP) elicited Ca(2+) flux in the soma, proximal apical and distal apical dendrites. At resting membrane potentials Ni(2+)-sensitive Ca(2+) channels do not contribute to the Ca(2+) signal in the proximal apical dendrite, but do contribute in the other cell regions. Spontaneous release from mossy fiber terminals acting on 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)-sensitive postsynaptic channels underlies a tonic inhibition of Ni(2+)-sensitive channels. Chelating Zn(2+) with CaEDTA blocks CNQX-sensitive changes in Ca(2+) flux implicating a mechanistic role of this ion in T-type Ca(2+) channel block. To test if this inhibition influenced excitability, progressively larger depolarizing pulses were delivered to CA3 pyramidal neurons. CNQX significantly reduced the size of the depolarizing step required to generate APs and increased the absolute number of APs per depolarizing step. This change in AP firing was completely reversed by the addition of Ni(2+). This mechanism may reduce the impact of T-type Ca(2+) channels in a region where large synaptic events are common.

A fraction enriched in rat hippocampal mossy fibre synaptosomes contains trophic activities.

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Taupin, P; Roisin, M P; Ben-Ari, Y; Barbin, G

1994-06-27

Subcellular fractions prepared from the rat hippocampus, were assessed for the presence of trophic activities. The cytosol of synaptosomal fractions induced mitotic reinitiation of confluent 3T3 fibroblasts. The synaptosomal fraction, enriched in mossy fibre terminals, contained the highest mitotic activity. The mitogenic activity was heat and trypsin sensitive, suggesting that polypeptides are involved. The cytosol of the mossy fibre synaptosomal fraction promoted neuritic outgrowth of PC 12 cells and embryonic hippocampal neurones in primary cultures. These results suggest that mossy fibres contain both mitogenic and neurotrophic activities. These factors could participate in mossy fibre sprouting that occur following brief seizures or experimental lesions.

Response of cat cerebellar vermis induced by sound. II. The role of the mossy and climbing fibers in acoustic transmission to the cerebellar cortex and influence of stimuli parameters.

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Jastreboff, P J; Tarnecki, R

1975-01-01

Experiments were performed on cats under Chloralose or Nembutal anesthesia. The parameters of the acoustic click stimuli were found to have a strong influence on the responses registered from both the surface of the cerebellar vermis lobuli V up VII as well as from single units. It was shown that a stimulus frequency rate not greater than 1/2 s should be used, since higher frequencies caused strong attenuation of the response. The type of anesthesia did not change the latencies of reactions of both evoked potentials and single units. However, decreasing the strength of the click resulted in increased response latencies, in the case of single unit reactions. A very strong influence of weak visual stimuli on units was also observed. It is suggested that mossy fibers are the most important fibers in the transmission of acoustic information to the cerebellar cortex.

Prenatal exposure to alcohol does not affect radial maze learning and hippocampal mossy fiber sizes in three inbred strains of mouse

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Bertholet Jean-Yves

2005-04-01

Full Text Available Abstract Background The aim of this study was to investigate the effects of prenatal alcohol exposure on radial-maze learning and hippocampal neuroanatomy, particularly the sizes of the intra- and infrapyramidal mossy fiber (IIPMF terminal fields, in three inbred strains of mice (C57BL/6J, BALB/cJ, and DBA/2J. Results Although we anticipated a modification of both learning and IIPMF sizes, no such effects were detected. Prenatal alcohol exposure did, however, interfere with reproduction in C57BL/6J animals and decrease body and brain weight (in interaction with the genotype at adult age. Conclusion Prenatal alcohol exposure influenced neither radial maze performance nor the sizes of the IIPMF terminal fields. We believe that future research should be pointed either at different targets when using mouse models for Fetal Alcohol Syndrome (e.g. more complicated behavioral paradigms, different hippocampal substructures, or other brain structures or involve different animal models.

Human limbic encephalitis serum enhances hippocampal mossy fiber-CA3 pyramidal cell synaptic transmission.

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Lalic, Tatjana; Pettingill, Philippa; Vincent, Angela; Capogna, Marco

2011-01-01

Limbic encephalitis (LE) is a central nervous system (CNS) disease characterized by subacute onset of memory loss and epileptic seizures. A well-recognized form of LE is associated with voltage-gated potassium channel complex antibodies (VGKC-Abs) in the patients' sera. We aimed to test the hypothesis that purified immunoglobulin G (IgG) from a VGKC-Ab LE serum would excite hippocampal CA3 pyramidal cells by reducing VGKC function at mossy-fiber (MF)-CA3 pyramidal cell synapses. We compared the effects of LE and healthy control IgG by whole-cell patch-clamp and extracellular recordings from CA3 pyramidal cells of rat hippocampal acute slices. We found that the LE IgG induced epileptiform activity at a population level, since synaptic stimulation elicited multiple population spikes extracellularly recorded in the CA3 area. Moreover, the LE IgG increased the rate of tonic firing and strengthened the MF-evoked synaptic responses. The synaptic failure of evoked excitatory postsynaptic currents (EPSCs) was significantly lower in the presence of the LE IgG compared to the control IgG. This suggests that the LE IgG increased the release probability on MF-CA3 pyramidal cell synapses compared to the control IgG. Interestingly, α-dendrotoxin (120 nm), a selective Kv1.1, 1.2, and 1.6 subunit antagonist of VGKC, mimicked the LE IgG-mediated effects. This is the first functional demonstration that LE IgGs reduce VGKC function at CNS synapses and increase cell excitability. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

β-Secretase BACE1 Promotes Surface Expression and Function of Kv3.4 at Hippocampal Mossy Fiber Synapses.

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Hartmann, Stephanie; Zheng, Fang; Kyncl, Michele C; Karch, Sandra; Voelkl, Kerstin; Zott, Benedikt; D'Avanzo, Carla; Lomoio, Selene; Tesco, Giuseppina; Kim, Doo Y; Alzheimer, Christian; Huth, Tobias

2018-04-04

The β-secretase β-site APP-cleaving enzyme 1 (BACE1) is deemed a major culprit in Alzheimer's disease, but accumulating evidence indicates that there is more to the enzyme than driving the amyloidogenic processing of the amyloid precursor protein. For example, BACE1 has emerged as an important regulator of neuronal activity through proteolytic and, most unexpectedly, also through nonproteolytic interactions with several ion channels. Here, we identify and characterize the voltage-gated K + channel 3.4 (Kv3.4) as a new and functionally relevant interaction partner of BACE1. Kv3.4 gives rise to A-type current with fast activating and inactivating kinetics and serves to repolarize the presynaptic action potential. We found that BACE1 and Kv3.4 are highly enriched and remarkably colocalized in hippocampal mossy fibers (MFs). In BACE1 -/- mice of either sex, Kv3.4 surface expression was significantly reduced in the hippocampus and, in synaptic fractions thereof, Kv3.4 was specifically diminished, whereas protein levels of other presynaptic K + channels such as K Ca 1.1 and K Ca 2.3 remained unchanged. The apparent loss of presynaptic Kv3.4 affected the strength of excitatory transmission at the MF-CA3 synapse in hippocampal slices of BACE1 -/- mice when probed with the Kv3 channel blocker BDS-I. The effect of BACE1 on Kv3.4 expression and function should be bidirectional, as predicted from a heterologous expression system, in which BACE1 cotransfection produced a concomitant upregulation of Kv3.4 surface level and current based on a physical interaction between the two proteins. Our data show that, by targeting Kv3.4 to presynaptic sites, BACE1 endows the terminal with a powerful means to regulate the strength of transmitter release. SIGNIFICANCE STATEMENT The β-secretase β-site APP-cleaving enzyme 1 (BACE1) is infamous for its crucial role in the pathogenesis of Alzheimer's disease, but its physiological functions in the intact nervous system are only gradually

Npas4 Is a Critical Regulator of Learning-Induced Plasticity at Mossy Fiber-CA3 Synapses during Contextual Memory Formation.

Science.gov (United States)

Weng, Feng-Ju; Garcia, Rodrigo I; Lutzu, Stefano; Alviña, Karina; Zhang, Yuxiang; Dushko, Margaret; Ku, Taeyun; Zemoura, Khaled; Rich, David; Garcia-Dominguez, Dario; Hung, Matthew; Yelhekar, Tushar D; Sørensen, Andreas Toft; Xu, Weifeng; Chung, Kwanghun; Castillo, Pablo E; Lin, Yingxi

2018-03-07

Synaptic connections between hippocampal mossy fibers (MFs) and CA3 pyramidal neurons are essential for contextual memory encoding, but the molecular mechanisms regulating MF-CA3 synapses during memory formation and the exact nature of this regulation are poorly understood. Here we report that the activity-dependent transcription factor Npas4 selectively regulates the structure and strength of MF-CA3 synapses by restricting the number of their functional synaptic contacts without affecting the other synaptic inputs onto CA3 pyramidal neurons. Using an activity-dependent reporter, we identified CA3 pyramidal cells that were activated by contextual learning and found that MF inputs on these cells were selectively strengthened. Deletion of Npas4 prevented both contextual memory formation and this learning-induced synaptic modification. We further show that Npas4 regulates MF-CA3 synapses by controlling the expression of the polo-like kinase Plk2. Thus, Npas4 is a critical regulator of experience-dependent, structural, and functional plasticity at MF-CA3 synapses during contextual memory formation. Copyright © 2018 Elsevier Inc. All rights reserved.

Local and Long-Range Circuit Connections to Hilar Mossy Cells in the Dentate Gyrus

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Sun, Yanjun; Grieco, Steven F.; Holmes, Todd C.

2017-01-01

Abstract Hilar mossy cells are the prominent glutamatergic cell type in the dentate hilus of the dentate gyrus (DG); they have been proposed to have critical roles in the DG network. To better understand how mossy cells contribute to DG function, we have applied new viral genetic and functional circuit mapping approaches to quantitatively map and compare local and long-range circuit connections of mossy cells and dentate granule cells in the mouse. The great majority of inputs to mossy cells consist of two parallel inputs from within the DG: an excitatory input pathway from dentate granule cells and an inhibitory input pathway from local DG inhibitory neurons. Mossy cells also receive a moderate degree of excitatory and inhibitory CA3 input from proximal CA3 subfields. Long range inputs to mossy cells are numerically sparse, and they are only identified readily from the medial septum and the septofimbrial nucleus. In comparison, dentate granule cells receive most of their inputs from the entorhinal cortex. The granule cells receive significant synaptic inputs from the hilus and the medial septum, and they also receive direct inputs from both distal and proximal CA3 subfields, which has been underdescribed in the existing literature. Our slice-based physiological mapping studies further supported the identified circuit connections of mossy cells and granule cells. Together, our data suggest that hilar mossy cells are major local circuit integrators and they exert modulation of the activity of dentate granule cells as well as the CA3 region through “back-projection” pathways. PMID:28451637

Dietary Supplementation of Hericium erinaceus Increases Mossy Fiber-CA3 Hippocampal Neurotransmission and Recognition Memory in Wild-Type Mice

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Federico Brandalise

2017-01-01

Full Text Available Hericium erinaceus (Bull. Pers. is a medicinal mushroom capable of inducing a large number of modulatory effects on human physiology ranging from the strengthening of the immune system to the improvement of cognitive functions. In mice, dietary supplementation with H. erinaceus prevents the impairment of spatial short-term and visual recognition memory in an Alzheimer model. Intriguingly other neurobiological effects have recently been reported like the effect on neurite outgrowth and differentiation in PC12 cells. Until now no investigations have been conducted to assess the impact of this dietary supplementation on brain function in healthy subjects. Therefore, we have faced the problem by considering the effect on cognitive skills and on hippocampal neurotransmission in wild-type mice. In wild-type mice the oral supplementation with H. erinaceus induces, in behaviour test, a significant improvement in the recognition memory and, in hippocampal slices, an increase in spontaneous and evoked excitatory synaptic current in mossy fiber-CA3 synapse. In conclusion, we have produced a series of findings in support of the concept that H. erinaceus induces a boost effect onto neuronal functions also in nonpathological conditions.

Dietary Supplementation of Hericium erinaceus Increases Mossy Fiber-CA3 Hippocampal Neurotransmission and Recognition Memory in Wild-Type Mice.

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Brandalise, Federico; Cesaroni, Valentina; Gregori, Andrej; Repetti, Margherita; Romano, Chiara; Orrù, Germano; Botta, Laura; Girometta, Carolina; Guglielminetti, Maria Lidia; Savino, Elena; Rossi, Paola

2017-01-01

Hericium erinaceus (Bull.) Pers. is a medicinal mushroom capable of inducing a large number of modulatory effects on human physiology ranging from the strengthening of the immune system to the improvement of cognitive functions. In mice, dietary supplementation with H. erinaceus prevents the impairment of spatial short-term and visual recognition memory in an Alzheimer model. Intriguingly other neurobiological effects have recently been reported like the effect on neurite outgrowth and differentiation in PC12 cells. Until now no investigations have been conducted to assess the impact of this dietary supplementation on brain function in healthy subjects. Therefore, we have faced the problem by considering the effect on cognitive skills and on hippocampal neurotransmission in wild-type mice. In wild-type mice the oral supplementation with H. erinaceus induces, in behaviour test, a significant improvement in the recognition memory and, in hippocampal slices, an increase in spontaneous and evoked excitatory synaptic current in mossy fiber-CA3 synapse. In conclusion, we have produced a series of findings in support of the concept that H. erinaceus induces a boost effect onto neuronal functions also in nonpathological conditions.

Presynaptic calcium signalling in cerebellar mossy fibres

DEFF Research Database (Denmark)

Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens

2010-01-01

Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX......)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers....... Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon...

Survival of mossy cells of the hippocampal dentate gyrus in humans with mesial temporal lobe epilepsy.

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Seress, László; Abrahám, Hajnalka; Horváth, Zsolt; Dóczi, Tamás; Janszky, József; Klemm, Joyce; Byrne, Richard; Bakay, Roy A E

2009-12-01

Hippocampal sclerosis can be identified in most patients with mesial temporal lobe epilepsy (TLE). Surgical removal of the sclerotic hippocampus is widely performed to treat patients with drug-resistant mesial TLE. In general, both epilepsy-prone and epilepsy-resistant neurons are believed to be in the hippocampal formation. The hilar mossy cells of the hippocampal dentate gyrus are usually considered one of the most vulnerable types of neurons. The aim of this study was to clarify the fate of mossy cells in the hippocampus in epileptic humans. Of the 19 patients included in this study, 15 underwent temporal lobe resection because of drug-resistant TLE. Four patients were used as controls because they harbored tumors that had not invaded the hippocampus and they had experienced no seizures. Histological evaluation of resected hippocampal tissues was performed using immunohistochemistry. Mossy cells were identified in the control as well as the epileptic hippocampi by using cocaine- and amphetamine-regulated transcript peptide immunohistochemistry. In most cases the number of mossy cells was reduced and thorny excrescences were smaller in the epileptic hippocampi than in controls; however, there was a significant loss of pyramidal cells and a partial loss of granule cells in the same epileptic hippocampi in which mossy cell loss was apparent. The loss of mossy cells could be correlated with the extent of hippocampal sclerosis, patient age at seizure onset, duration of epilepsy, and frequency of seizures. In many cases large numbers of mossy cells were present in the hilus of the dentate gyrus when most pyramidal neurons of the CA1 and CA3 areas of the Ammon's horn were lost, suggesting that mossy cells may not be more vulnerable to epileptic seizures than the hippocampal pyramidal neurons.

Radioisotopic investigations of zinc uptake into brain slices

International Nuclear Information System (INIS)

Howell, G.A.

1983-01-01

The presence of zinc in the vicinity of the hippocampal mossy fibers has been repeatedly demonstrated, and several lines of evidence suggest that the mossy-fiber zinc is concentrated within the terminals of mossy fibers. In search of insight into the metabolism and function of mossy-fiber zinc, the present study investigated the transport of zinc into tissue slices and the response of the zinc transport to depolarization. Kinetic analysis of zinc accumulation by mouse brain slices in vitro revealed the presence of a high affinity uptake component with an apparent Km of 17.7 μM for hippocampus, 16.6 μM< for cortex and 25 μM for striatum and a V/sub max/ of 9.2 ng/mg/hr for the hippocampus, 10.1 ng/mg/hr for cortex and 9.6 ng/mg/hr for striatum. Cytoarchitectonic differences in zinc transport between the different hippocampal subregions were found with those regions containing granule cells or mossy fiber axons accumulating greater amounts of zinc than the CA 1 region. The present finding that mossy-fiber neuropil selectivity accumulates zinc suggests the presence of a zinc-binding substance unique to mossy-fiber tissue

Differences in kainate receptor involvement in hippocampal mossy fibre long-term potentiation depending on slice orientation.

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Sherwood, John L; Amici, Mascia; Dargan, Sheila L; Culley, Georgia R; Fitzjohn, Stephen M; Jane, David E; Collingridge, Graham L; Lodge, David; Bortolotto, Zuner A

2012-09-01

Long-term potentiation (LTP) is a well-established experimental model used to investigate the synaptic basis of learning and memory. LTP at mossy fibre - CA3 synapses in the hippocampus is unusual because it is normally N-methyl-d-aspartate (NMDA) receptor-independent. Instead it seems that the trigger for mossy fibre LTP involves kainate receptors (KARs). Although it is generally accepted that pre-synaptic KARs play an essential role in frequency facilitation and LTP, their subunit composition remains a matter of significant controversy. We have reported previously that both frequency facilitation and LTP can be blocked by selective antagonism of GluK1 (formerly GluR5/Glu(K5))-containing KARs, but other groups have failed to reproduce this effect. Moreover, data from receptor knockout and mRNA expression studies argue against a major role of GluK1, supporting a more central role for GluK2 (formerly GluR6/Glu(K6)). A potential reason underlying the controversy in the pharmacological experiments may reside in differences in the preparations used. Here we show differences in pharmacological sensitivity of synaptic plasticity at mossy fibre - CA3 synapses depend critically on slice orientation. In transverse slices, LTP of fEPSPs was invariably resistant to GluK1-selective antagonists whereas in parasagittal slices LTP was consistently blocked by GluK1-selective antagonists. In addition, there were pronounced differences in the magnitude of frequency facilitation and the sensitivity to the mGlu2/3 receptor agonist DCG-IV. Using anterograde labelling of granule cells we show that slices of both orientations possess intact mossy fibres and both large and small presynaptic boutons. Transverse slices have denser fibre tracts but a smaller proportion of giant mossy fibre boutons. These results further demonstrate a considerable heterogeneity in the functional properties of the mossy fibre projection. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of a Dietary Fiber on Development of Dimethylhydrazine-Induced Aberrant Crypt Foci and Colon Tumor Incidence in Wistar Rats

DEFF Research Database (Denmark)

Thorup, I.; Meyer, Otto A.; Kristiansen, E.

1994-01-01

Formation of aberrant crypt foci (ACF) in archived colon tissue from animals in a previous study was examined. The animals were fed a semisynthetic casein-based diet in which the carbohydrate pool was substituted with a dietary beet fiber (Fibeta) as the only source of fiber. Oral doses...... experimental data. The present state of knowledge could indicate that ACF represent true preneoplastic lesions progressing into colon tumors or that ACF and colon tumors represent two parallel independent events as a consequence of the cancer initiation (i.e., the ACF not being preneoplastic lesions per se)....... between duration of intake of high-fiber diet and number of animals with ACF, as well as the total number of ACF and number of small A CF (1-3 crypts) per affected animal. The previously reported data showed no protective effect of the dietary fiber at any stage of the colorectal carcinogenic process...

Adolescent mice show anxiety- and aggressive-like behavior and the reduction of long-term potentiation in mossy fiber-CA3 synapses after neonatal maternal separation.

Science.gov (United States)

Shin, S Y; Han, S H; Woo, R-S; Jang, S H; Min, S S

2016-03-01

Exposure to maternal separation (MS) during early life is an identified risk factor for emotional disorders such as anxiety and depression later in life. This study investigated the effects of neonatal MS on the behavior and long-term potentiation (LTP) as well as basic synaptic transmission at hippocampal CA3-CA1 and mossy fiber (MF)-CA3 synapses in adolescent mice for 19days. When mice were adolescents, we measured depression, learning, memory, anxious and aggressive behavior using the forced swimming test (FST), Y-maze, Morris water maze (MWM), elevated plus maze (EPM), three consecutive days of the open field test, the social interaction test, the tube-dominance test and the resident-intruder test. The results showed that there was no difference in FST, Y-maze, and MWM performance. However, MS mice showed more anxiety-like behavior in the EPM test and aggressive-like behavior in the tube-dominance and resident-intruder tests. In addition, the magnitude of LTP and release probability in the MF-CA3 synapses was reduced in the MS group but not in the CA3-CA1 synapse. Our results indicate that early life stress due to MS may induce anxiety- and aggressive-like behavior during adolescence, and these effects are associated with synaptic plasticity at the hippocampal MF-CA3 synapses. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Non-synaptic signaling from cerebellar climbing fibers modulates Golgi cell activity.

Science.gov (United States)

Nietz, Angela K; Vaden, Jada H; Coddington, Luke T; Overstreet-Wadiche, Linda; Wadiche, Jacques I

2017-10-13

Golgi cells are the principal inhibitory neurons at the input stage of the cerebellum, providing feedforward and feedback inhibition through mossy fiber and parallel fiber synapses. In vivo studies have shown that Golgi cell activity is regulated by climbing fiber stimulation, yet there is little functional or anatomical evidence for synapses between climbing fibers and Golgi cells. Here, we show that glutamate released from climbing fibers activates ionotropic and metabotropic receptors on Golgi cells through spillover-mediated transmission. The interplay of excitatory and inhibitory conductances provides flexible control over Golgi cell spiking, allowing either excitation or a biphasic sequence of excitation and inhibition following single climbing fiber stimulation. Together with prior studies of spillover transmission to molecular layer interneurons, these results reveal that climbing fibers exert control over inhibition at both the input and output layers of the cerebellar cortex.

Replacement of asymmetric synaptic profiles in the molecular layer of dentate gyrus following cycloheximide in the pilocarpine model in rats.

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Simone eBittencourt

2015-11-01

Full Text Available Mossy fiber sprouting is among the best-studied forms of post-lesional synaptic plasticity and is regarded by many as contributory to seizures in both humans and animal models of epilepsy. It is not known whether mossy fiber sprouting increases the number of synapses in the molecular layer or merely replaces lost contacts. Using the pilocarpine model of status epilepticus to induce mossy fiber sprouting, and cycloheximide to block this sprouting, we evaluated at the ultrastructural level the number and type of asymmetric synaptic contacts in the molecular layer of the dentate gyrus. As expected, whereas pilocarpine-treated rats had dense silver grain deposits in the inner molecular layer (reflecting mossy fiber sprouting, pilocarpine+cycloheximide-treated animals did not differ from controls. Both groups of treated rats (Pilo group and CHX+Pilo group had reduced density of asymmetric synaptic profiles (putative excitatory synaptic contacts, which was greater for cycloheximide-treated animals. For both treated groups the loss of excitatory synaptic contacts was even greater in the outer molecular layer than in the best studied inner molecular layer (in which mossy fiber sprouting occurs. These results indicate that mossy fiber sprouting tends to replace lost synaptic contacts rather than increase the absolute number of contacts. We speculate that the overall result is more consistent with restored rather than with increased excitability.

PlexinA2 Forward Signaling through Rap1 GTPases Regulates Dentate Gyrus Development and Schizophrenia-like Behaviors

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Xiao-Feng Zhao

2018-01-01

Full Text Available Summary: Dentate gyrus (DG development requires specification of granule cell (GC progenitors in the hippocampal neuroepithelium, as well as their proliferation and migration into the primordial DG. We identify the Plexin family members Plxna2 and Plxna4 as important regulators of DG development. Distribution of immature GCs is regulated by Sema5A signaling through PlxnA2 and requires a functional PlxnA2 GTPase-activating protein (GAP domain and Rap1 small GTPases. In adult Plxna2−/− but not Plxna2-GAP-deficient mice, the dentate GC layer is severely malformed, neurogenesis is compromised, and mossy fibers form aberrant synaptic boutons within CA3. Behavioral studies with Plxna2−/− mice revealed deficits in associative learning, sociability, and sensorimotor gating—traits commonly observed in neuropsychiatric disorder. Remarkably, while morphological defects are minimal in Plxna2-GAP-deficient brains, defects in fear memory and sensorimotor gating persist. Since allelic variants of human PLXNA2 and RAP1 associate with schizophrenia, our studies identify a biochemical pathway important for brain development and mental health. : Zhao et al. find that Sema5A-PlexinA2 forward signaling through Rap1 GTPases is required for progenitor distribution in the developing mouse dentate gyrus. Adult Plxna2−/−, but not Plxna2-GAP-deficient, mice show defects in dentate morphology, neurogenesis, and mossy fiber connectivity. Plxna2−/− and Plxna2-GAP mice exhibit behavioral defects suggestive of neuropsychiatric illness. Keywords: PlexinA2, semaphoring, Rap1, GAP, dentate gyrus, adult neurogenesis, mossy fiber, fear memory, sensorimotor gating, schizophrenia

Aberrations in preliminary design of ITER divertor impurity influx monitor

Energy Technology Data Exchange (ETDEWEB)

Kitazawa, Sin-iti, E-mail: kitazawa.siniti@jaea.go.jp [Naka Fusion Institute, Japan Atomic Energy Agency, JAEA, Naka 311-0193 (Japan); Ogawa, Hiroaki [Naka Fusion Institute, Japan Atomic Energy Agency, JAEA, Naka 311-0193 (Japan); Katsunuma, Atsushi; Kitazawa, Daisuke [Core Technology Center, Nikon Corporation, Yokohama 244-8533 (Japan); Ohmori, Keisuke [Customized Products Business Unit, Nikon Corporation, Mito 310-0843 (Japan)

2015-12-15

Highlights: • Divertor impurity influx monitor for ITER (DIM) is procured by JADA. • DIM is designed to observe light from nuclear fusion plasma directly. • DIM is under preliminary design phase. • The spot diagrams were suppressed within the core of receiving fiber. • The aberration of DIM is suppressed in the preliminary design. - Abstract: Divertor impurity influx monitor for ITER (DIM) is a diagnostic system that observes light from nuclear fusion plasma directly. This system is affected by various aberrations because it observes light from the fan-array chord near the divertor in the ultraviolet–near infrared wavelength range. The aberrations should be suppressed to the extent possible to observe the light with very high spatial resolution. In the preliminary design of DIM, spot diagrams were suppressed within the core of the receiving fiber's cross section, and the resulting spatial resolutions satisfied the design requirements.

Aberrations in preliminary design of ITER divertor impurity influx monitor

International Nuclear Information System (INIS)

Kitazawa, Sin-iti; Ogawa, Hiroaki; Katsunuma, Atsushi; Kitazawa, Daisuke; Ohmori, Keisuke

2015-01-01

Highlights: • Divertor impurity influx monitor for ITER (DIM) is procured by JADA. • DIM is designed to observe light from nuclear fusion plasma directly. • DIM is under preliminary design phase. • The spot diagrams were suppressed within the core of receiving fiber. • The aberration of DIM is suppressed in the preliminary design. - Abstract: Divertor impurity influx monitor for ITER (DIM) is a diagnostic system that observes light from nuclear fusion plasma directly. This system is affected by various aberrations because it observes light from the fan-array chord near the divertor in the ultraviolet–near infrared wavelength range. The aberrations should be suppressed to the extent possible to observe the light with very high spatial resolution. In the preliminary design of DIM, spot diagrams were suppressed within the core of the receiving fiber's cross section, and the resulting spatial resolutions satisfied the design requirements.

Ketogenic diet change cPLA2/clusterin and autophagy related gene expression and correlate with cognitive deficits and hippocampal MFs sprouting following neonatal seizures.

Science.gov (United States)

Ni, Hong; Zhao, Dong-Jing; Tian, Tian

2016-02-01

Because the ketogenic diet (KD) was affecting expression of energy metabolism- related genes in hippocampus and because lipid membrane peroxidation and its associated autophagy stress were also found to be involved in energy depletion, we hypothesized that KD might exert its neuroprotective action via lipid membrane peroxidation and autophagic signaling. Here, we tested this hypothesis by examining the long-term expression of lipid membrane peroxidation-related cPLA2 and clusterin, its downstream autophagy marker Beclin-1, LC3 and p62, as well as its execution molecule Cathepsin-E following neonatal seizures and chronic KD treatment. On postnatal day 9 (P9), 48 Sprague-Dawley rats were randomly assigned to two groups: flurothyl-induced recurrent seizures group and control group. On P28, they were further randomly divided into the seizure group without ketogenic diet (RS+ND), seizure plus ketogenic diet (RS+KD), the control group without ketogenic diet (NS+ND), and the control plus ketogenic diet (NS+KD). Morris water maze test was performed during P37-P43. Then mossy fiber sprouting and the protein levels were detected by Timm staining and Western blot analysis, respectively. Flurothyl-induced RS+ND rats show a long-term lower amount of cPLA2 and LC3II/I, and higher amount of clusterin, Beclin-1, p62 and Cathepsin-E which are in parallel with hippocampal mossy fiber sprouting and cognitive deficits. Furthermore, chronic KD treatment (RS+KD) is effective in restoring these molecular, neuropathological and cognitive changes. The results imply that a lipid membrane peroxidation and autophagy-associated pathway is involved in the aberrant hippocampal mossy fiber sprouting and cognitive deficits following neonatal seizures, which might be a potential target of KD for the treatment of neonatal seizure-induced brain damage. Copyright © 2015 Elsevier B.V. All rights reserved.

Activity-dependent control of NMDA receptor subunit composition at hippocampal mossy fibre synapses.

Science.gov (United States)

Carta, Mario; Srikumar, Bettadapura N; Gorlewicz, Adam; Rebola, Nelson; Mulle, Christophe

2018-02-15

CA3 pyramidal cells display input-specific differences in the subunit composition of synaptic NMDA receptors (NMDARs). Although at low density, GluN2B contributes significantly to NMDAR-mediated EPSCs at mossy fibre synapses. Long-term potentiation (LTP) of NMDARs triggers a modification in the subunit composition of synaptic NMDARs by insertion of GluN2B. GluN2B subunits are essential for the expression of LTP of NMDARs at mossy fibre synapses. Single neurons express NMDA receptors (NMDARs) with distinct subunit composition and biophysical properties that can be segregated in an input-specific manner. The dynamic control of the heterogeneous distribution of synaptic NMDARs is crucial to control input-dependent synaptic integration and plasticity. In hippocampal CA3 pyramidal cells from mice of both sexes, we found that mossy fibre (MF) synapses display a markedly lower proportion of GluN2B-containing NMDARs than associative/commissural synapses. The mechanism involved in such heterogeneous distribution of GluN2B subunits is not known. Here we show that long-term potentiation (LTP) of NMDARs, which is selectively expressed at MF-CA3 pyramidal cell synapses, triggers a modification in the subunit composition of synaptic NMDARs by insertion of GluN2B. This activity-dependent recruitment of GluN2B at mature MF-CA3 pyramidal cell synapses contrasts with the removal of GluN2B subunits at other glutamatergic synapses during development and in response to activity. Furthermore, although expressed at low levels, GluN2B is necessary for the expression of LTP of NMDARs at MF-CA3 pyramidal cell synapses. Altogether, we reveal a previously unknown activity-dependent regulation and function of GluN2B subunits that may contribute to the heterogeneous plasticity induction rules in CA3 pyramidal cells. © 2017 Centre Nationnal de la Recherche Scientifique. The Journal of Physiology © 2017 The Physiological Society.

Wavefront sensing and adaptive control in phased array of fiber collimators

Science.gov (United States)

Lachinova, Svetlana L.; Vorontsov, Mikhail A.

2011-03-01

A new wavefront control approach for mitigation of atmospheric turbulence-induced wavefront phase aberrations in coherent fiber-array-based laser beam projection systems is introduced and analyzed. This approach is based on integration of wavefront sensing capabilities directly into the fiber-array transmitter aperture. In the coherent fiber array considered, we assume that each fiber collimator (subaperture) of the array is capable of precompensation of local (onsubaperture) wavefront phase tip and tilt aberrations using controllable rapid displacement of the tip of the delivery fiber at the collimating lens focal plane. In the technique proposed, this tip and tilt phase aberration control is based on maximization of the optical power received through the same fiber collimator using the stochastic parallel gradient descent (SPGD) technique. The coordinates of the fiber tip after the local tip and tilt aberrations are mitigated correspond to the coordinates of the focal-spot centroid of the optical wave backscattered off the target. Similar to a conventional Shack-Hartmann wavefront sensor, phase function over the entire fiber-array aperture can then be retrieved using the coordinates obtained. The piston phases that are required for coherent combining (phase locking) of the outgoing beams at the target plane can be further calculated from the reconstructed wavefront phase. Results of analysis and numerical simulations are presented. Performance of adaptive precompensation of phase aberrations in this laser beam projection system type is compared for various system configurations characterized by the number of fiber collimators and atmospheric turbulence conditions. The wavefront control concept presented can be effectively applied for long-range laser beam projection scenarios for which the time delay related with the double-pass laser beam propagation to the target and back is compared or even exceeds the characteristic time of the atmospheric turbulence change

Novel adaptive fiber-optics collimator for coherent beam combination.

Science.gov (United States)

Zhi, Dong; Ma, Pengfei; Ma, Yanxing; Wang, Xiaolin; Zhou, Pu; Si, Lei

2014-12-15

In this manuscript, we experimentally validate a novel design of adaptive fiber-optics collimator (AFOC), which utilizes two levers to enlarge the movable range of the fiber end cap. The enlargement of the range makes the new AFOC possible to compensate the end-cap/tilt aberration in fiber laser beam combining system. The new AFOC based on flexible hinges and levers was fabricated and the performance of the new AFOC was tested carefully, including its control range, frequency response and control accuracy. Coherent beam combination (CBC) of two 5-W fiber amplifiers array with simultaneously end-cap/tilt control and phase-locking control was implemented successfully with the novel AFOC. Experimental results show that the average normalized power in the bucket (PIB) value increases from 0.311 to 0.934 with active phasing and tilt aberration compensation simultaneously, and with both controls on, the fringe contrast improves to more than 82% from 0% for the case with both control off. This work presents a promising structure for tilt aberration control in high power CBC system.

Efficacité comparée de deux méthodes de maîtrise de la reproduction de la brebis Djalonké, variété 'Mossi'

Directory of Open Access Journals (Sweden)

Boly, H.

2000-01-01

Full Text Available Estrous Synchronisation in Djalonke, var. 'Mossi' Ewes : Comparison of Hormonal Treatment and Ram Effect. Zootechnical (ram effect and hormonal (Fluoro Gestone Acetate or FGA, and Pregnant Mare Serum Gonodotropin or PMSG methods on estrous and parturition synchronisation were tested on 24 Djalonke var. 'Mossi' ewes. The use of ram jumping combined with plasma progesterone assay showed that the zootechnical method using male effect provides better estrous synchronisation (4.8 + 2.2 days for estrous delay and better gathering of parturition (within 8 days. The hormonal method by FGA + PMSG provide good estrous synchronisation (3.1 + 20days but lead to a weak lam-bing gathering (within 21 days. After hormonal induction of estrous, a lower fertility was observed and seems to be related to the doses of FGA and PMSG with were relatively high for these small format of Djalonke var. 'Mossi' breed.

The morpho/functional discrepancy in the cerebellar cortex: Looks alone are deceptive.

Directory of Open Access Journals (Sweden)

Dan Rokni

2008-12-01

Full Text Available In a recent report we demonstrated that stimulation of cerebellar mossy fibers synchronously activates Purkinje cells that are located directly above the site of stimulation. We found that the activated Purkinje cells are arranged in a radial patch on the cerebellar surface and that this organization is independent of the integrity of the inhibitory system. This arrangement of activity is counterintuitive. The anatomical structure with the extensive parallel fiber system implies that mossy fiber stimulation will activate Purkinje cells along a beam of parallel fibers. In this short review we highlight this discrepancy between anatomical structure and functional dynamics and suggest a plausible underlying mechanism.

Chromosomal aberration

International Nuclear Information System (INIS)

Ishii, Yutaka

1988-01-01

Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G 2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G 2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G 2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G 1 phase. (author)

Spike timing regulation on the millisecond scale by distributed synaptic plasticity at the cerebellum input stage: a simulation study

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Jesus A Garrido

2013-05-01

Full Text Available The way long-term synaptic plasticity regulates neuronal spike patterns is not completely understood. This issue is especially relevant for the cerebellum, which is endowed with several forms of long-term synaptic plasticity and has been predicted to operate as a timing and a learning machine. Here we have used a computational model to simulate the impact of multiple distributed synaptic weights in the cerebellar granular layer network. In response to mossy fiber bursts, synaptic weights at multiple connections played a crucial role to regulate spike number and positioning in granule cells. The weight at mossy fiber to granule cell synapses regulated the delay of the first spike and the weight at mossy fiber and parallel fiber to Golgi cell synapses regulated the duration of the time-window during which the first-spike could be emitted. Moreover, the weights of synapses controlling Golgi cell activation regulated the intensity of granule cell inhibition and therefore the number of spikes that could be emitted. First spike timing was regulated with millisecond precision and the number of spikes ranged from 0 to 3. Interestingly, different combinations of synaptic weights optimized either first-spike timing precision or spike number, efficiently controlling transmission and filtering properties. These results predict that distributed synaptic plasticity regulates the emission of quasi-digital spike patterns on the millisecond time scale and allows the cerebellar granular layer to flexibly control burst transmission along the mossy fiber pathway.

α-Synuclein expression in the mouse cerebellum is restricted to VGluT1 excitatory terminals and is enriched in unipolar brush cells.

Science.gov (United States)

Lee, Sun Kyong; Sillitoe, Roy V; Silva, Coralie; Martina, Marco; Sekerkova, Gabriella

2015-10-01

α-Synuclein has a crucial role in synaptic vesicle release and synaptic membrane recycling. Although its general expression pattern has been described in the cerebellum, the precise cerebellar structures where α-synuclein is localized are poorly understood. To address this question, we used α-synuclein immunohistochemistry in adult mice cerebellar sections. We found that α-synuclein labels glutamatergic but not glycinergic and GABAergic synaptic terminals in the molecular and granule cell layers. α-Synuclein was preferentially expressed in parallel and mossy fiber synaptic terminals that also express vesicular glutamate transporter 1 (VGluT1), while it was not detected in VGluT2-positive climbing fibers. α-Synuclein was particularly enriched in lobules IX and X, a region known to contain a high density of unipolar brush cells (UBCs). To elucidate whether the α-synuclein-positive mossy fibers belong to UBCs, we double-labeled cerebellar sections with antibodies to α-synuclein and UBC-type-specific markers (calretinin for type I and metabotropic glutamate receptor 1α (mGluR1α) for type II UBCs) and took advantage of organotypic cerebellar cultures (in which all mossy fibers are UBC axons) and moonwalker mice (in which almost all UBCs are ablated) and found that both type I and type II UBCs express α-synuclein. In moonwalker mutant cerebella, the α-synuclein/VGluT1 immunolabeling showed a dramatic decrease in the vestibulocerebellum that correlated with the absence of UBC. α-Synuclein appears to be an excellent marker for intrinsic mossy fibers of the VGluT1 subset in conjunction with UBCs of both subtypes.

Optical Aberrations and Wavefront

Directory of Open Access Journals (Sweden)

Nihat Polat

2014-08-01

Full Text Available The deviation of light to create normal retinal image in the optical system is called aberration. Aberrations are divided two subgroup: low-order aberrations (defocus: spherical and cylindrical refractive errors and high-order aberrations (coma, spherical, trefoil, tetrafoil, quadrifoil, pentafoil, secondary astigmatism. Aberrations increase with aging. Spherical aberrations are compensated by positive corneal and negative lenticular spherical aberrations in youth. Total aberrations are elevated by positive corneal and positive lenticular spherical aberrations in elderly. In this study, we aimed to analyze the basic terms regarding optic aberrations which have gained significance recently. (Turk J Ophthalmol 2014; 44: 306-11

Dentate gyrus mossy cells control spontaneous convulsive seizures and spatial memory.

Science.gov (United States)

Bui, Anh D; Nguyen, Theresa M; Limouse, Charles; Kim, Hannah K; Szabo, Gergely G; Felong, Sylwia; Maroso, Mattia; Soltesz, Ivan

2018-02-16

Temporal lobe epilepsy (TLE) is characterized by debilitating, recurring seizures and an increased risk for cognitive deficits. Mossy cells (MCs) are key neurons in the hippocampal excitatory circuit, and the partial loss of MCs is a major hallmark of TLE. We investigated how MCs contribute to spontaneous ictal activity and to spatial contextual memory in a mouse model of TLE with hippocampal sclerosis, using a combination of optogenetic, electrophysiological, and behavioral approaches. In chronically epileptic mice, real-time optogenetic modulation of MCs during spontaneous hippocampal seizures controlled the progression of activity from an electrographic to convulsive seizure. Decreased MC activity is sufficient to impede encoding of spatial context, recapitulating observed cognitive deficits in chronically epileptic mice. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Controllable parabolic lensed liquid-core optical fiber by using electrostatic force.

Science.gov (United States)

Tang, Chun Yin; Zhang, Xuming; Chai, Yang; Hui, Long; Tao, Lili; Tsang, Yuen H

2014-08-25

For typical optical fiber system, an external lens accessory set is required to adjust the optical path of output light, which however is limited by the fixed parameter of the lens accessory setup. Considering spherical aberration in the imaging process and its small focusable spot size, a complicated lens combination is required to compensate the aberration. This paper has demonstrated a unique method to fabricate liquid-core lensed fibers by filling water and NOA61 respectively into hollow Teflon AF fibers and silicate fiber, the radius of curvature of the liquid lens can be controlled by adjusting the applied voltage on the core liquid and even parabolic shape lens can be produced with enough applied voltage. The experiment has successfully demonstrated a variation of focal length from 0.628 mm to 0.111 mm responding to the change of applied voltage from 0V to 3.2KV (L = 2mm) for the Teflon AF fiber, as well as a variation of focal length from 0.274 mm to 0.08 mm responding to the change of applied voltage from 0V to 3KV (L = 2mm) for the silicate fiber. Further simulation shows that the focused spot size can be reduced to 2 µm by adjusting the refractive index and fiber geometry. Solid state parabolic lensed fiber can be produced after NOA61 is solidified by the UV curing.

Dynamic properties of sensory stimulation evoked responses in mouse cerebellar granule cell layer and molecular layer.

Science.gov (United States)

Bing, Yan-Hua; Zhang, Guang-Jian; Sun, Lei; Chu, Chun-Ping; Qiu, De-Lai

2015-01-12

Sensory information coming from climbing fiber and mossy fiber-granule cell pathways, generates motor-related outputs according to internal rules of integration and computation in the cerebellar cortex. However, the dynamic properties of sensory information processing in mouse cerebellar cortex are less understood. Here, we studied the dynamic properties of sensory stimulation-evoked responses in the cerebellar granule cell layer (GCL) and molecular layer (ML) by electrophysiological recordings method. Our data showed that air-puff stimulation (5-10 ms in duration) of the ipsilateral whisker pad evoked single-peak responses in the GCL and ML; whereas a duration of stimulation ≥30 ms in GCL and ≥60 ms in ML, evoked double-peak responses that corresponded with stimulation-on and -off responses via mossy fiber pathway. The highest frequency of stimulation train for evoking GCL responses was 33 Hz. In contrast, the highest frequency of stimulation train for evoking ML responses was 4 Hz. These results indicate that the cerebellar granule cells transfer the high-fidelity sensory information from mossy fibers, which is cut-off by molecular layer interneurons (MLIs). Our results suggest that the MLIs network acts as a low-pass filter during the processing of high-frequency sensory information. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Determination of aberration center of Ronchigram for automated aberration correctors in scanning transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Sannomiya, Takumi, E-mail: sannomiya@mtl.titech.ac.jp [Tokyo Institute of Technology, Ookayama, Tokyo (Japan); Sawada, Hidetaka; Nakamichi, Tomohiro; Hosokawa, Fumio [JEOL Limited, Akishima, Tokyo (Japan); Nakamura, Yoshio; Tanishiro, Yasumasa; Takayanagi, Kunio [Tokyo Institute of Technology, Ookayama, Tokyo (Japan)

2013-12-15

A generic method to determine the aberration center is established, which can be utilized for aberration calculation and axis alignment for aberration corrected electron microscopes. In this method, decentering induced secondary aberrations from inherent primary aberrations are minimized to find the appropriate axis center. The fitness function to find the optimal decentering vector for the axis was defined as a sum of decentering induced secondary aberrations with properly distributed weight values according to the aberration order. Since the appropriate decentering vector is determined from the aberration values calculated at an arbitrary center axis, only one aberration measurement is in principle required to find the center, resulting in /very fast center search. This approach was tested for the Ronchigram based aberration calculation method for aberration corrected scanning transmission electron microscopy. Both in simulation and in experiments, the center search was confirmed to work well although the convergence to find the best axis becomes slower with larger primary aberrations. Such aberration center determination is expected to fully automatize the aberration correction procedures, which used to require pre-alignment of experienced users. This approach is also applicable to automated aperture positioning. - Highlights: • A generic method to determine the aberration center is established for (S)TEM. • Decentering induced secondary aberrations are utilized to find the center. • The method is tested on Ronchigrams both in simulation and experiment. • Proper weighting of the aberration gives a good convergence. • Larger primary aberration results in a slower convergence.

Possible mechanisms of chromosome aberrations. 2. Formation of aberrations after UV-irradiation

International Nuclear Information System (INIS)

Lebedeva, L.I.

1982-01-01

One of mechanisms of chromosome aberrations after UV-radiation of animal cells initiated by thymine dimerization from different dna threads (by cross joints) and finished in mitosis metaphase is discussed. The model of aberration formation, taking a count of peculiarities of chromosome ansate structure and predicting the important role of chromosome isolation during mitosis in realization of structural aberrations, is suggested. An attempt to present aberration formation under conditions of exact repair is the distinguishing feature of the model

Low-energy foil aberration corrector

International Nuclear Information System (INIS)

Aken, R.H. van; Hagen, C.W.; Barth, J.E.; Kruit, P.

2002-01-01

A spherical and chromatic aberration corrector for electron microscopes is proposed, consisting of a thin foil sandwiched between two apertures. The electrons are retarded at the foil to almost zero energy, so that they can travel ballistically through the foil. It is shown that such a low-voltage corrector has a negative spherical aberration for not too large distances between aperture and foil, as well as a negative chromatic aberration. For various distances the third- and fifth-order spherical aberration coefficients and the first- and second-order chromatic aberration coefficients are calculated using ray tracing. Provided that the foils have sufficient electron transmission the corrector is able to correct the third-order spherical aberration and the first-order chromatic aberration of a typical low-voltage scanning electron microscope. Preliminary results show that the fifth-order spherical aberration and the second-order chromatic aberration can be kept sufficiently low

Studies on the development of mossy zinc electrodeposits from flowing alkaline electrolytes

Energy Technology Data Exchange (ETDEWEB)

Mc Vay, L.

1991-07-01

The initiation and characteristics of mossy zinc electrodeposits have been investigated. Batteries with zinc electrodes are candidates for electric vehicle applications; however, this electrode is prone to form non-compact deposits that contribute to capacity loss and battery failure. Moss is deposited when the current density is far from the limiting current. This morphology first appears only after the bulk deposit is approximately 1 {mu}m thick. In this investigation, the effects of flow rate (Re=0--4000), current density (0--50 mA/cm{sup 2}), concentration of the electroactive species (0.25 and 0.5 M), and the concentration of supporting electrolyte (3, 6, and 12 M) on the initiation of moss were examined. The rotating concentric cylinder electrode was employed for most of the experiments; and a flow channel was used to study the development of morphology. After the experiment, the deposit was characterized using microscopic, x-ray diffraction, and profilometric techniques. 94 refs., 72 figs.

Cytoarchitectonic distribution of zinc in the hippocampus of man and the rat

International Nuclear Information System (INIS)

Frederickson, C.J.; Klitenick, M.A.; Manton, W.I.; Kirkpatrick, J.B.

1983-01-01

Zinc was measured in whole hippocampus and in hippocampal sub-regions by stable-isotope dilution mass spectrometry. Lyophilized tissues were spiked by a precisely-known amount of zinc-64. The zinc-64/zinc-66 isotope ratio was determined by mass spectrometry. In both man and the rat, the most zinc (102-145 ppm, dry weight) was found in the hilar region, the least (27-35) in the fimbria. The amount of zinc directly associated with mossy-fiber axons was estimated to be approximately 8% of the total zinc in the hippocampus, and the concentration of mossy-fiber zinc was estimated at 220-300 μM. Methodological and theoretical implications of the quantitative findings were discussed. (Auth.)

Loss of protohaem IX farnesyltransferase in mature dentate granule cells impairs short-term facilitation at mossy fibre to CA3 pyramidal cell synapses.

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Booker, Sam A; Campbell, Graham R; Mysiak, Karolina S; Brophy, Peter J; Kind, Peter C; Mahad, Don J; Wyllie, David J A

2017-03-15

Neurodegenerative disorders can exhibit dysfunctional mitochondrial respiratory chain complex IV activity. Conditional deletion of cytochrome c oxidase, the terminal enzyme in the respiratory electron transport chain of mitochondria, from hippocampal dentate granule cells in mice does not affect low-frequency dentate to CA3 glutamatergic synaptic transmission. High-frequency dentate to CA3 glutamatergic synaptic transmission and feedforward inhibition are significantly attenuated in cytochrome c oxidase-deficient mice. Intact presynaptic mitochondrial function is critical for the short-term dynamics of mossy fibre to CA3 synaptic function. Neurodegenerative disorders are characterized by peripheral and central symptoms including cognitive impairments which have been associated with reduced mitochondrial function, in particular mitochondrial respiratory chain complex IV or cytochrome c oxidase activity. In the present study we conditionally removed a key component of complex IV, protohaem IX farnesyltransferase encoded by the COX10 gene, in granule cells of the adult dentate gyrus. Utilizing whole-cell patch-clamp recordings from morphologically identified CA3 pyramidal cells from control and complex IV-deficient mice, we found that reduced mitochondrial function did not result in overt deficits in basal glutamatergic synaptic transmission at the mossy-fibre synapse because the amplitude, input-output relationship and 50 ms paired-pulse facilitation were unchanged following COX10 removal from dentate granule cells. However, trains of stimuli given at high frequency (> 20 Hz) resulted in dramatic reductions in short-term facilitation and, at the highest frequencies (> 50 Hz), also reduced paired-pulse facilitation, suggesting a requirement for adequate mitochondrial function to maintain glutamate release during physiologically relevant activity patterns. Interestingly, local inhibition was reduced, suggesting the effect observed was not restricted to synapses

The effect of aberrated recording beams on reflecting Bragg gratings

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SeGall, Marc; Ott, Daniel; Divliansky, Ivan; Glebov, Leonid B.

2013-03-01

The effect of aberrations present in the recording beams of a holographic setup is discussed regarding the period and spectral response of a reflecting volume Bragg grating. Imperfect recording beams result in spatially varying resonant wavelengths and the side lobes of the spectrum are washed out. Asymmetrical spectra, spectral broadening, and a reduction in peak diffraction efficiency may also be present, though these effects are less significant for gratings with wider spectral widths. Reflecting Bragg gratings (RBGs) are used as elements in a variety of applications including spectral beam combining1,2, mode locking3,4, longitudinal and transverse mode selection in lasers5,6, and sensing7,8. For applications requiring narrow spectral selectivity9, or large apertures10, these gratings must have a uniform period throughout the length of the recording medium, which may be on the order of millimeters. However, when using typical recording techniques such as two-beam interference for large aperture gratings and phase-mask recording of fiber gratings, aberrations from the optical elements in the system result in an imperfect grating structure11-13. In this paper we consider the effects of aberrations on large aperture gratings recorded in thick media using the two-beam interference technique. Previous works in analyzing the effects of aberrations have considered the effects of aberrations in a single recording plane where the beams perfectly overlap. Such an approach is valid for thin media (on the order of tens of microns), but for thick recording media (on the order of several millimeters) there will be a significant shift in the positions of the beams relative to each other as they traverse the recording medium. Therefore, the fringe pattern produced will not be constant throughout the grating if one or both beams have a non-uniform wavefront. Such non-uniform gratings may have a wider spectral width, a shifted resonant wavelength, or other problems. It is

Optical traps with geometric aberrations

International Nuclear Information System (INIS)

Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G.

2006-01-01

We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems

Dopamine D1/D5, but not D2/D3, receptor dependency of synaptic plasticity at hippocampal mossy fiber synapses that is enabled by patterned afferent stimulation, or spatial learning

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Hardy Hagena

2016-09-01

Full Text Available Although the mossy fiber (MF synapses of the hippocampal CA3 region display quite distinct properties in terms of the molecular mechanisms that underlie synaptic plasticity, they nonetheless exhibit persistent (>24h synaptic plasticity that is akin to that observed at the Schaffer collateral (SCH-CA1 and perforant path (PP-dentate gyrus (DG synapses of freely behaving rats. In addition, they also respond to novel spatial learning with very enduring forms of long-term potentiation (LTP and long-term depression (LTD. These latter forms of synaptic plasticity are directly related to the learning behavior: novel exploration of generalized changes in space facilitates the expression of LTP at MF-CA3 synapses, whereas exploration of novel configurations of large environmental features facilitates the expression of LTD. In the absence of spatial novelty, synaptic plasticity is not expressed. Motivation is a potent determinant of whether learning about spatial experience effectively occurs and the neuromodulator dopamine plays a key role in motivation-based learning. Prior research on the regulation by dopamine receptors of long-term synaptic plasticity in CA1 and dentate gyrus synapses in vivo suggests that whereas D2/D3 receptors may modulate a general predisposition toward expressing plasticity, D1/D5 receptors may directly regulate the direction of change in synaptic strength that occurs during learning. Although the CA3 region is believed to play a pivotal role in many forms of learning, the role of these receptors in persistent (>24h forms of synaptic plasticity at MF-CA3 synapses is unknown. Here, we report that whereas pharmacological antagonism of D2/D3 receptors had no impact on LTP or LTD, antagonism of D1/D5 receptors significantly impaired LTP and LTD that were induced by solely by means of patterned afferent stimulation, or LTP/LTD that are typically enhanced by the conjunction of afferent stimulation and novel spatial learning. These data

A robot conditioned reflex system modeled after the cerebellum.

Science.gov (United States)

Albus, J. S.

1972-01-01

Reduction of a theory of cerebellar function to computer software for the control of a mechanical manipulator. This reduction is achieved by considering the cerebellum, along with the higher-level brain centers which control it, as a type of finite-state machine with input entering the cerebellum via mossy fibers from the periphery and output from the cerebellum occurring via Purkinje cells. It is hypothesized that the cerebellum learns by an error-correction system similar to Perceptron training algorithms. An electromechanical model of the cerebellum is then developed for the control of a mechanical arm. The problem of modeling the granular layer which selects the set of parallel fibers which are active at any instant of time is considered, and a relevance matrix is constructed to model the relative degree of influence which mossy fibers from the various joints have on the sets of granule cells unique to each joint.

Mask-induced aberration in EUV lithography

Science.gov (United States)

Nakajima, Yumi; Sato, Takashi; Inanami, Ryoichi; Nakasugi, Tetsuro; Higashiki, Tatsuhiko

2009-04-01

We estimated aberrations using Zernike sensitivity analysis. We found the difference of the tolerated aberration with line direction for illumination. The tolerated aberration of perpendicular line for illumination is much smaller than that of parallel line. We consider this difference to be attributable to the mask 3D effect. We call it mask-induced aberration. In the case of the perpendicular line for illumination, there was a difference in CD between right line and left line without aberration. In this report, we discuss the possibility of pattern formation in NA 0.25 generation EUV lithography tool. In perpendicular pattern for EUV light, the dominant part of aberration is mask-induced aberration. In EUV lithography, pattern correction based on the mask topography effect will be more important.

Camera processing with chromatic aberration.

Science.gov (United States)

Korneliussen, Jan Tore; Hirakawa, Keigo

2014-10-01

Since the refractive index of materials commonly used for lens depends on the wavelengths of light, practical camera optics fail to converge light to a single point on an image plane. Known as chromatic aberration, this phenomenon distorts image details by introducing magnification error, defocus blur, and color fringes. Though achromatic and apochromatic lens designs reduce chromatic aberration to a degree, they are complex and expensive and they do not offer a perfect correction. In this paper, we propose a new postcapture processing scheme designed to overcome these problems computationally. Specifically, the proposed solution is comprised of chromatic aberration-tolerant demosaicking algorithm and post-demosaicking chromatic aberration correction. Experiments with simulated and real sensor data verify that the chromatic aberration is effectively corrected.

Structural analysis of radiation-induced chromosome aberrations by atomic force microscope (AFM) before and after Giemsa staining

International Nuclear Information System (INIS)

Murakami, M.; Kanda, R.; Minamihisamatsu, M.; Hayata, I.

2003-01-01

Full text: We have studied structures of chromosome aberration induced by ionizing radiation by an atomic force microscope (AFM). The AFM could visualize the fine structure of chromosomes on Giemsa stained or unstained samples, although it was difficult to visualize unstained chromosomes by light microscope. The height data of chromosomes obtained by AFM provided useful information to describe detailed structure of chromatid gaps induced by heavy ion irradiation. A fibrous structure was observed on the unstained chromosome and these structures were considered to be the 30nm fibers on the chromosome. These types of structures were observed in the gaps as well as on surface of the chromosome. Further more, other types of chromosome aberration induced by ionizing radiation visualized by AFM will be presented

Physiological properties of afferents to the rat cerebellum during normal development and after postnatal x irradiation

International Nuclear Information System (INIS)

Puro, D.G.

1975-01-01

The consequences of an altered cerebellar cortical development on afferent transmission and terminal organization were analyzed in adult rats which had received x irradiation to the cerebellum postnatally. Rats, anesthetized with 0.5 percent halothane, were studied in various ages from day 3 to adult. The ascending mossy and climbing fiber systems were activated by electrical stimulation of the limbs with needle electrodes. Stimulation of the motor cortex activated the descending climbing fiber pathways. Extracellular responses from cerebellar Purkinje cells were observed on an oscilloscope as poststimulus time histograms were constructed ''on-line''. Conclusions and assertions include: (1) Synaptogenesis between incoming afferent fibers and target neurons takes place early in cerebellar cortical development. (2) Mossy fiber transmission is mature before the bulk of cerebellar synaptogenesis occurs. (3) The ascending and descending components of the climbing fiber system mature, with respect to latency, in synchrony. (4) The terminal synaptic organization has little effect on the development of transmission characteristics in these afferent systems. (5) One possible mechanism by which an adult neural structure can have an abnormal synaptic organization is to maintain immature synaptic relationships due to the neonatal loss of interneurons

Aberrant Myokine Signaling in Congenital Myotonic Dystrophy

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Masayuki Nakamori

2017-10-01

Full Text Available Summary: Myotonic dystrophy types 1 (DM1 and 2 (DM2 are dominantly inherited neuromuscular disorders caused by a toxic gain of function of expanded CUG and CCUG repeats, respectively. Although both disorders are clinically similar, congenital myotonic dystrophy (CDM, a severe DM form, is found only in DM1. CDM is also characterized by muscle fiber immaturity not observed in adult DM, suggesting specific pathological mechanisms. Here, we revealed upregulation of the interleukin-6 (IL-6 myokine signaling pathway in CDM muscles. We also found a correlation between muscle immaturity and not only IL-6 expression but also expanded CTG repeat length and CpG methylation status upstream of the repeats. Aberrant CpG methylation was associated with transcriptional dysregulation at the repeat locus, increasing the toxic RNA burden that upregulates IL-6. Because the IL-6 pathway is involved in myocyte maturation and muscle atrophy, our results indicate that enhanced RNA toxicity contributes to severe CDM phenotypes through aberrant IL-6 signaling. : Congenital myotonic dystrophy (CDM manifests characteristic genetic (very large CTG repeat expansions, epigenetic (CpG hypermethylation upstream of the repeat, and phenotypic (muscle immaturity features not seen in adult DM. Nakamori et al. find phenotype-genotype and epigenotype correlation in CDM muscle and reveal involvement of the IL-6 myokine signaling pathway in the disease process. Keywords: CTCF, ER stress, IL-6, muscular dystrophy, NF-κB, trinucleotide, cytokine, splicing

Correlations between corneal and total wavefront aberrations

Science.gov (United States)

Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

2002-06-01

Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

Non-random intrachromosomal distribution of radiation-induced chromatid aberrations in Vicia faba. [Aberration clustering

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Schubert, I; Rieger, R [Akademie der Wissenschaften der DDR, Gatersleben. Zentralinst. fuer Genetik und Kulturpflanzenforschung

1976-04-01

A reconstructed karyotype of Vicia faba, with all chromosomes individually distinguishable, was treated with X-rays, fast neutrons, (/sup 3/H) uridine (/sup 3/HU). The distribution within metaphase chromosomes of induced chromatid aberrations was non-random for all agents used. Aberration clustering, in part agent specific, occurred in chromosome segments containing heterochromatin as defined by the presence of G bands. The pattern of aberration clustering found after treatment with /sup 3/HU did not allow the recognition of chromosome regions active in transcription during treatment. Furthermore, it was impossible to obtain unambiguous indications of the presence of AT- and GC-base clusters from the patterns of /sup 3/HT- and /sup 3/HC-induced chromatid aberrations, respectively. Possible reasons underlying these observations are discussed.

The cerebellar Golgi cell and spatiotemporal organization of granular layer activity

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Egidio eD‘Angelo

2013-05-01

Full Text Available The cerebellar granular layer has been suggested to perform a complex spatiotemporal reconfiguration of incoming mossy fiber signals. Central to this role is the inhibitory action exerted by Golgi cells over granule cells: Golgi cells inhibit granule cells through double feedforward and feedback inhibitory loops and generate a broad lateral inhibition that extends beyond the afferent synaptic field. This characteristic connectivity has recently been investigated in great detail and been correlated with specific functional properties of the neuron. These include theta-frequency pacemaking, network entrainment into coherent oscillations and phase resetting. Important advances have also been made in terms of determining the membrane and synaptic properties of the neuron, and clarifying the mechanisms of activation by input bursts. Moreover, voltage sensitive dye imaging and multi-electrode array recordings, combined with mathematical simulations based on realistic computational models, have improved our understanding of the impact of Golgi cell activity on granular layer circuit computations. These investigations have highlighted the critical role of Golgi cells in: generating dense clusters of granule cell activity organized in center-surround structures, implementing combinatorial operations on multiple mossy fiber inputs, regulating transmission gain and cut-off frequency, controlling spike timing and burst transmission, and determining the sign, intensity and extension of long-term synaptic plasticity at the mossy fiber-granule cell relay. This review considers recent advances in the field, highlighting the functional implications of Golgi cells for granular layer network computation and indicating new challenges for cerebellar research.

Corruption of the dentate gyrus by "dominant" granule cells: Implications for dentate gyrus function in health and disease.

Science.gov (United States)

Scharfman, Helen E; Myers, Catherine E

2016-03-01

The dentate gyrus (DG) and area CA3 of the hippocampus are highly organized lamellar structures which have been implicated in specific cognitive functions such as pattern separation and pattern completion. Here we describe how the anatomical organization and physiology of the DG and CA3 are consistent with structures that perform pattern separation and completion. We then raise a new idea related to the complex circuitry of the DG and CA3 where CA3 pyramidal cell 'backprojections' play a potentially important role in the sparse firing of granule cells (GCs), considered important in pattern separation. We also propose that GC axons, the mossy fibers, already known for their highly specialized structure, have a dynamic function that imparts variance--'mossy fiber variance'--which is important to pattern separation and completion. Computational modeling is used to show that when a subset of GCs become 'dominant,' one consequence is loss of variance in the activity of mossy fiber axons and a reduction in pattern separation and completion in the model. Empirical data are then provided using an example of 'dominant' GCs--subsets of GCs that develop abnormally and have increased excitability. Notably, these abnormal GCs have been identified in animal models of disease where DG-dependent behaviors are impaired. Together these data provide insight into pattern separation and completion, and suggest that behavioral impairment could arise from dominance of a subset of GCs in the DG-CA3 network. Copyright © 2015 Elsevier Inc. All rights reserved.

Iteration of ultrasound aberration correction methods

Science.gov (United States)

Maasoey, Svein-Erik; Angelsen, Bjoern; Varslot, Trond

2004-05-01

Aberration in ultrasound medical imaging is usually modeled by time-delay and amplitude variations concentrated on the transmitting/receiving array. This filter process is here denoted a TDA filter. The TDA filter is an approximation to the physical aberration process, which occurs over an extended part of the human body wall. Estimation of the TDA filter, and performing correction on transmit and receive, has proven difficult. It has yet to be shown that this method works adequately for severe aberration. Estimation of the TDA filter can be iterated by retransmitting a corrected signal and re-estimate until a convergence criterion is fulfilled (adaptive imaging). Two methods for estimating time-delay and amplitude variations in receive signals from random scatterers have been developed. One method correlates each element signal with a reference signal. The other method use eigenvalue decomposition of the receive cross-spectrum matrix, based upon a receive energy-maximizing criterion. Simulations of iterating aberration correction with a TDA filter have been investigated to study its convergence properties. A weak and strong human-body wall model generated aberration. Both emulated the human abdominal wall. Results after iteration improve aberration correction substantially, and both estimation methods converge, even for the case of strong aberration.

Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

International Nuclear Information System (INIS)

Kumari, S. Sindhu; Varadaraj, Kulandaiappan

2014-01-01

Highlights: • Intact AQP0 functions as fiber cell-to-fiber cell adhesion protein. • AQP0 facilitates reduction in extracellular space and lens water content. • AQP0 adhesion function aids in lens refractive index gradient (RING) formation. • AQP0 prevents lens spherical aberration by establishing RING. • AQP0 is critical for lens transparency and homeostasis. - Abstract: Aquaporin 0 (AQP0) is a transmembrane channel that constitutes ∼45% of the total membrane protein of the fiber cells in mammalian lens. It is critical for lens transparency and homeostasis as mutations and knockout cause autosomal dominant lens cataract. AQP0 functions as a water channel and as a cell-to-cell adhesion (CTCA) molecule in the lens. Our recent in vitro studies showed that the CTCA function of AQP0 could be crucial to establish lens refractive index gradient (RING). However, there is a lack of in vivo data to corroborate the role of AQP0 as a fiber CTCA molecule which is critical for creating lens RING. The present investigation is undertaken to gather in vivo evidence for the involvement of AQP0 in developing lens RING. Lenses of wild type (WT) mouse, AQP0 knockout (heterozygous, AQP0 +/− ) and AQP0 knockout lens transgenically expressing AQP1 (heterozygous AQP0 +/− /AQP1 +/− ) mouse models were used for the study. Data on AQP0 protein profile of intact and N- and/or C-terminal cleaved AQP0 in the lens by MALDI-TOF mass spectrometry and SDS–PAGE revealed that outer cortex fiber cells have only intact AQP0 of ∼28 kDa, inner cortical and outer nuclear fiber cells have both intact and cleaved forms, and inner nuclear fiber cells have only cleaved forms (∼26–24 kDa). Knocking out of 50% of AQP0 protein caused light scattering, spherical aberration (SA) and cataract. Restoring the lost fiber cell membrane water permeability (P f ) by transgene AQP1 did not reinstate complete lens transparency and the mouse lenses showed light scattering and SA. Transmission and

Mechanisms and functional roles of glutamatergic synapse diversity in a cerebellar circuit

NARCIS (Netherlands)

Zampini, Valeria; Liu, Jian K; Diana, Marco A; Maldonado, Paloma P; Brunel, Nicolas; Dieudonné, Stéphane

2016-01-01

Synaptic currents display a large degree of heterogeneity of their temporal characteristics, but the functional role of such heterogeneities remains unknown. We investigated in rat cerebellar slices synaptic currents in Unipolar Brush Cells (UBCs), which generate intrinsic mossy fibers relaying

TACTILE STIMULATION EVOKES LONG-LASTING POTENTIATION OF PURKINJE CELL DISCHARGE IN VIVO

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Ramakrishnan eKanchipuram

2016-02-01

Full Text Available In the cerebellar network, a precise relationship between plasticity and neuronal discharge has been predicted. However, the potential generation of persistent changes in PC spike discharge as a consequence of plasticity following natural stimulation patterns has not been clearly determined. Here we show that facial tactile stimuli organized in theta-patterns can induce stereotyped NMDA and GABA-A receptor-dependent changes in Purkinje cell (PCs and molecular layer interneuron (MLIs firing: invariably, all PCs showed a long-lasting increase (spike-related potentiation or SR-P and MLIs a long-lasting decrease (spike-related suppression or SR-S in baseline activity and spike response probability. These observations suggests that natural sensory stimulation engages multiple long-term plastic changes that are distributed along the mossy fiber – parallel fiber pathway and operate synergistically to potentiate spike generation in PCs. In contrast, theta-pattern electrical stimulation of PFs indistinctly induced SR-P and SR-S both in PCs and MLIs, suggesting that natural sensory stimulation preordinates plasticity upstream of the PF-PC synapse. All these effects occurred in the absence of complex spike changes, supporting the theoretical prediction that Purkinje cell activity is potentiated when the mossy fiber - parallel fiber system is activated in the absence of conjunctive climbing fiber activity.

[Monochromatic aberration in accommodation. Dynamic wavefront analysis].

Science.gov (United States)

Fritzsch, M; Dawczynski, J; Jurkutat, S; Vollandt, R; Strobel, J

2011-06-01

Monochromatic aberrations may influence the visual acuity of the eye. They are not stable and can be affected by different factors. The subject of the following paper is the dynamic investigation of the changes in wavefront aberration with accommodation. Dynamic measurement of higher and lower order aberrations was performed with a WASCA Wavefront Analyzer (Carl-Zeiss-Meditec) and a specially constructed target device for aligning objects in far and near distances on 25 subjects aged from 15 to 27 years old. Wavefront aberrations showed some significant changes in accommodation. In addition to the characteristic sphere reaction accompanying miosis and changes in horizontal prism (Z(1) (1)) in the sense of a convergence movement of the eyeball also occurred. Furthermore defocus rose (Z(2) (0)) and astigmatism (Z(2) (-2)) changed. In higher-order aberrations a decrease in coma-like Zernike polynomials (Z(3) (-1), Z(3) (1)) was found. The most obvious change appeared in spherical aberration (Z(4) (0)) which increased and changed from positive to negative. In addition the secondary astigmatism (Z(4) (-2)) and quadrafoil (Z(4) (4)) rise also increased. The total root mean square (RMS), as well as the higher-order aberrations (RMS-HO) significantly increased in accommodation which is associated with a theoretical reduction of visual acuity. An analysis of the influence of pupil size on aberrations showed significant increases in defocus, spherical aberration, quadrafoil, RMS and RMS HO by increasing pupil diameter. By accommodation-associated miosis, the growing aberrations are partially compensated by focusing on near objects. Temporal analysis of the accommodation process with dynamic wavefront analysis revealed significant delays in pupil response and changing of prism in relation to the sphere reaction. In accommodation to near objects a discrete time ahead of third order aberrations in relation to the sphere response was found. Using dynamic wavefront measurement

The prediction of spherical aberration with schematic eyes.

Science.gov (United States)

Liou, H L; Brennan, N A

1996-07-01

Many model eyes have been proposed; they differ in optical characteristics and therefore have different aberrations and image quality. In predicting the visual performance of the eye, we are most concerned with the central foveal vision. Spherical aberration is the only on-axis monochromatic aberration and can be used as a criterion to assess the degree of resemblance of eye models to the human eye. We reviewed and compiled experimental values of the spherical aberration of the eye, calculated the spherical aberration of several different categories of model eyes and compared the calculated results to the experimental data. Results show an over-estimation of spherical aberration by all models, the finite schematic eyes predicting values of spherical aberration closest to the experimental data. Current model eyes do not predict the average experimental values of the spherical aberration of the eye. A new model eye satisfying this assessment criterion is required for investigations of the visual performance of the eye.

Imaging characteristics of Zernike and annular polynomial aberrations.

Science.gov (United States)

Mahajan, Virendra N; Díaz, José Antonio

2013-04-01

The general equations for the point-spread function (PSF) and optical transfer function (OTF) are given for any pupil shape, and they are applied to optical imaging systems with circular and annular pupils. The symmetry properties of the PSF, the real and imaginary parts of the OTF, and the modulation transfer function (MTF) of a system with a circular pupil aberrated by a Zernike circle polynomial aberration are derived. The interferograms and PSFs are illustrated for some typical polynomial aberrations with a sigma value of one wave, and 3D PSFs and MTFs are shown for 0.1 wave. The Strehl ratio is also calculated for polynomial aberrations with a sigma value of 0.1 wave, and shown to be well estimated from the sigma value. The numerical results are compared with the corresponding results in the literature. Because of the same angular dependence of the corresponding annular and circle polynomial aberrations, the symmetry properties of systems with annular pupils aberrated by an annular polynomial aberration are the same as those for a circular pupil aberrated by a corresponding circle polynomial aberration. They are also illustrated with numerical examples.

Geometric characteristics of aberrations of plane-symmetric optical systems

International Nuclear Information System (INIS)

Lu Lijun; Deng Zhiyong

2009-01-01

The geometric characteristics of aberrations of plane-symmetric optical systems are studied in detail with a wave-aberration theory. It is dealt with as an extension of the Seidel aberrations to realize a consistent aberration theory from axially symmetric to plane-symmetric systems. The aberration distribution is analyzed with the spot diagram of a ray and an aberration curve. Moreover, the root-mean-square value and the centroid of aberration distribution are discussed. The numerical results are obtained with the focusing optics of a toroidal mirror at grazing incidence.

Nodal aberration theory applied to freeform surfaces

Science.gov (United States)

Fuerschbach, Kyle; Rolland, Jannick P.; Thompson, Kevin P.

2014-12-01

When new three-dimensional packages are developed for imaging optical systems, the rotational symmetry of the optical system is often broken, changing its imaging behavior and making the optical performance worse. A method to restore the performance is to use freeform optical surfaces that compensate directly the aberrations introduced from tilting and decentering the optical surfaces. In order to effectively optimize the shape of a freeform surface to restore optical functionality, it is helpful to understand the aberration effect the surface may induce. Using nodal aberration theory the aberration fields induced by a freeform surface in an optical system are explored. These theoretical predications are experimentally validated with the design and implementation of an aberration generating telescope.

How informative are spatial CA3 representations established by the dentate gyrus?

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Erika Cerasti

2010-04-01

Full Text Available In the mammalian hippocampus, the dentate gyrus (DG is characterized by sparse and powerful unidirectional projections to CA3 pyramidal cells, the so-called mossy fibers. Mossy fiber synapses appear to duplicate, in terms of the information they convey, what CA3 cells already receive from entorhinal cortex layer II cells, which project both to the dentate gyrus and to CA3. Computational models of episodic memory have hypothesized that the function of the mossy fibers is to enforce a new, well-separated pattern of activity onto CA3 cells, to represent a new memory, prevailing over the interference produced by the traces of older memories already stored on CA3 recurrent collateral connections. Can this hypothesis apply also to spatial representations, as described by recent neurophysiological recordings in rats? To address this issue quantitatively, we estimate the amount of information DG can impart on a new CA3 pattern of spatial activity, using both mathematical analysis and computer simulations of a simplified model. We confirm that, also in the spatial case, the observed sparse connectivity and level of activity are most appropriate for driving memory storage-and not to initiate retrieval. Surprisingly, the model also indicates that even when DG codes just for space, much of the information it passes on to CA3 acquires a non-spatial and episodic character, akin to that of a random number generator. It is suggested that further hippocampal processing is required to make full spatial use of DG inputs.

A realistic large-scale model of the cerebellum granular layer predicts circuit spatio-temporal filtering properties

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Sergio Solinas

2010-05-01

Full Text Available The way the cerebellar granular layer transforms incoming mossy fiber signals into new spike patterns to be related to Purkinje cells is not yet clear. Here, a realistic computational model of the granular layer was developed and used to address four main functional hypotheses: center-surround organization, time-windowing, high-pass filtering in responses to spike bursts and coherent oscillations in response to diffuse random activity. The model network was activated using patterns inspired by those recorded in vivo. Burst stimulation of a small mossy fiber bundle resulted in granule cell bursts delimited in time (time windowing and space (center-surround by network inhibition. This burst-burst transmission showed marked frequency-dependence configuring a high-pass filter with cut-off frequency around 100 Hz. The contrast between center and surround properties was regulated by the excitatory-inhibitory balance. The stronger excitation made the center more responsive to 10-50 Hz input frequencies and enhanced the granule cell output (with spike occurring earlier and with higher frequency and number compared to the surround. Finally, over a certain level of mossy fiber background activity, the circuit generated coherent oscillations in the theta-frequency band. All these processes were fine-tuned by NMDA and GABA-A receptor activation and neurotransmitter vesicle cycling in the cerebellar glomeruli. This model shows that available knowledge on cellular mechanisms is sufficient to unify the main functional hypotheses on the cerebellum granular layer and suggests that this network can behave as an adaptable spatio-temporal filter coordinated by theta-frequency oscillations.

Neuropathologic features of the hippocampus and amygdala in cats with familial spontaneous epilepsy.

Science.gov (United States)

Yu, Yoshihiko; Hasegawa, Daisuke; Hamamoto, Yuji; Mizoguchi, Shunta; Kuwabara, Takayuki; Fujiwara-Igarashi, Aki; Tsuboi, Masaya; Chambers, James Ken; Fujita, Michio; Uchida, Kazuyuki

2018-03-01

OBJECTIVE To investigate epilepsy-related neuropathologic changes in cats of a familial spontaneous epileptic strain (ie, familial spontaneous epileptic cats [FSECs]). ANIMALS 6 FSECs, 9 age-matched unrelated healthy control cats, and 2 nonaffected (without clinical seizures)dams and 1 nonaffected sire of FSECs. PROCEDURES Immunohistochemical analyses were used to evaluate hippocampal sclerosis, amygdaloid sclerosis, mossy fiber sprouting, and granule cell pathological changes. Values were compared between FSECs and control cats. RESULTS Significantly fewer neurons without gliosis were detected in the third subregion of the cornu ammonis (CA) of the dorsal and ventral aspects of the hippocampus as well as the central nucleus of the amygdala in FSECs versus control cats. Gliosis without neuronal loss was also observed in the CA4 subregion of the ventral aspect of the hippocampus. No changes in mossy fiber sprouting and granule cell pathological changes were detected. Moreover, similar changes were observed in the dams and sire without clinical seizures, although to a lesser extent. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that the lower numbers of neurons in the CA3 subregion of the hippocampus and the central nucleus of the amygdala were endophenotypes of familial spontaneous epilepsy in cats. In contrast to results of other veterinary medicine reports, severe epilepsy-related neuropathologic changes (eg, hippocampal sclerosis, amygdaloid sclerosis, mossy fiber sprouting, and granule cell pathological changes) were not detected in FSECs. Despite the use of a small number of cats with infrequent seizures, these findings contributed new insights on the pathophysiologic mechanisms of genetic-related epilepsy in cats.

Seizure frequency correlates with loss of dentate gyrus GABAergic neurons in a mouse model of temporal lobe epilepsy

Science.gov (United States)

Buckmaster, Paul S.; Abrams, Emily; Wen, Xiling

2018-01-01

Epilepsy occurs in one of 26 people. Temporal lobe epilepsy is common and can be difficult to treat effectively. It can develop after brain injuries that damage the hippocampus. Multiple pathophysiological mechanisms involving the hippocampal dentate gyrus have been proposed. This study evaluated a mouse model of temporal lobe epilepsy to test which pathological changes in the dentate gyrus correlate with seizure frequency and help prioritize potential mechanisms for further study. FVB mice (n = 127) that had experienced status epilepticus after systemic treatment with pilocarpine 31–61 days earlier were video-monitored for spontaneous, convulsive seizures 9 hr/day every day for 24–36 days. Over 4,060 seizures were observed. Seizure frequency ranged from an average of one every 3.6 days to one every 2.1 hr. Hippocampal sections were processed for Nissl stain, Prox1-immunocytochemistry, GluR2-immunocytochemistry, Timm stain, glial fibrillary acidic protein-immunocytochemistry, glutamic acid decarboxylase in situ hybridization, and parvalbumin-immunocytochemistry. Stereological methods were used to measure hilar ectopic granule cells, mossy cells, mossy fiber sprouting, astrogliosis, and GABAergic interneurons. Seizure frequency was not significantly correlated with the generation of hilar ectopic granule cells, the number of mossy cells, the extent of mossy fiber sprouting, the extent of astrogliosis, or the number of GABAergic interneurons in the molecular layer or hilus. Seizure frequency significantly correlated with the loss of GABAergic interneurons in or adjacent to the granule cell layer, but not with the loss of parvalbumin-positive interneurons. These findings prioritize the loss of granule cell layer interneurons for further testing as a potential cause of temporal lobe epilepsy. PMID:28425097

Seizure frequency correlates with loss of dentate gyrus GABAergic neurons in a mouse model of temporal lobe epilepsy.

Science.gov (United States)

Buckmaster, Paul S; Abrams, Emily; Wen, Xiling

2017-08-01

Epilepsy occurs in one of 26 people. Temporal lobe epilepsy is common and can be difficult to treat effectively. It can develop after brain injuries that damage the hippocampus. Multiple pathophysiological mechanisms involving the hippocampal dentate gyrus have been proposed. This study evaluated a mouse model of temporal lobe epilepsy to test which pathological changes in the dentate gyrus correlate with seizure frequency and help prioritize potential mechanisms for further study. FVB mice (n = 127) that had experienced status epilepticus after systemic treatment with pilocarpine 31-61 days earlier were video-monitored for spontaneous, convulsive seizures 9 hr/day every day for 24-36 days. Over 4,060 seizures were observed. Seizure frequency ranged from an average of one every 3.6 days to one every 2.1 hr. Hippocampal sections were processed for Nissl stain, Prox1-immunocytochemistry, GluR2-immunocytochemistry, Timm stain, glial fibrillary acidic protein-immunocytochemistry, glutamic acid decarboxylase in situ hybridization, and parvalbumin-immunocytochemistry. Stereological methods were used to measure hilar ectopic granule cells, mossy cells, mossy fiber sprouting, astrogliosis, and GABAergic interneurons. Seizure frequency was not significantly correlated with the generation of hilar ectopic granule cells, the number of mossy cells, the extent of mossy fiber sprouting, the extent of astrogliosis, or the number of GABAergic interneurons in the molecular layer or hilus. Seizure frequency significantly correlated with the loss of GABAergic interneurons in or adjacent to the granule cell layer, but not with the loss of parvalbumin-positive interneurons. These findings prioritize the loss of granule cell layer interneurons for further testing as a potential cause of temporal lobe epilepsy. © 2017 Wiley Periodicals, Inc.

Neurobehavioral Deficits in a Rat Model of Recurrent Neonatal Seizures Are Prevented by a Ketogenic Diet and Correlate with Hippocampal Zinc/Lipid Transporter Signals.

Science.gov (United States)

Tian, Tian; Ni, Hong; Sun, Bao-liang

2015-10-01

The ketogenic diet (KD) has been shown to be effective as an antiepileptic therapy in adults, but it has not been extensively tested for its efficacy in neonatal seizure-induced brain damage. We have previously shown altered expression of zinc/lipid metabolism-related genes in hippocampus following penicillin-induced developmental model of epilepsy. In this study, we further investigated the effect of KD on the neurobehavioral and cognitive deficits, as well as if KD has any influence in the activity of zinc/lipid transporters such as zinc transporter 3 (ZnT-3), MT-3, ApoE, ApoJ (clusterin), and ACAT-1 activities in neonatal rats submitted to flurothyl-induced recurrent seizures. Postnatal day 9 (P9), 48 Sprague-Dawley rats were randomly assigned to two groups: flurothyl-induced recurrent seizure group (EXP) and control group (CONT). On P28, they were further randomly divided into the seizure group without ketogenic diet (EXP1), seizure plus ketogenic diet (EXP2), the control group without ketogenic diet (CONT1), and the control plus ketogenic diet (CONT2). Neurological behavioral parameters of brain damage (plane righting reflex, cliff avoidance reflex, and open field test) were observed from P35 to P49. Morris water maze test was performed during P51-P57. Then hippocampal mossy fiber sprouting and the protein levels of ZnT3, MT3, ApoE, CLU, and ACAT-1 were detected by Timm staining and Western blot analysis, respectively. Flurothyl-induced neurobehavioral toxicology and aberrant mossy fiber sprouting were blocked by KD. In parallel with these behavioral changes, rats treated with KD (EXP2) showed a significant down-regulated expression of ZnT-3, MT-3, ApoE, clusterin, and ACAT-1 in hippocampus when compared with the non-KD-treated EXP1 group. Our findings provide support for zinc/lipid transporter signals being potential targets for the treatment of neonatal seizure-induced brain damage by KD.

Aberration characteristics of immersion lenses for LVSEM

International Nuclear Information System (INIS)

Khursheed, Anjam

2002-01-01

This paper investigates the on-axis aberration characteristics of various immersion objective lenses for low voltage scanning electron microscopy (LVSEM). A simple aperture lens model is used to generate smooth axial field distributions. The simulation results show that mixed field electric-magnetic immersion lenses are predicted to have between 1.5 and 2 times smaller aberration limited probe diameters than their pure-field counterparts. At a landing energy of 1 keV, mixed field immersion lenses operating at the vacuum electrical field breakdown limit are predicted to have on-axis aberration coefficients between 50 and 60 μm, yielding an ultimate image resolution of below 1 nm. These aberrations lie in the same range as those for LVSEM systems that employ aberration correctors

Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

Energy Technology Data Exchange (ETDEWEB)

Kumari, S. Sindhu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, New York, NY (United States)

2014-10-03

Highlights: • Intact AQP0 functions as fiber cell-to-fiber cell adhesion protein. • AQP0 facilitates reduction in extracellular space and lens water content. • AQP0 adhesion function aids in lens refractive index gradient (RING) formation. • AQP0 prevents lens spherical aberration by establishing RING. • AQP0 is critical for lens transparency and homeostasis. - Abstract: Aquaporin 0 (AQP0) is a transmembrane channel that constitutes ∼45% of the total membrane protein of the fiber cells in mammalian lens. It is critical for lens transparency and homeostasis as mutations and knockout cause autosomal dominant lens cataract. AQP0 functions as a water channel and as a cell-to-cell adhesion (CTCA) molecule in the lens. Our recent in vitro studies showed that the CTCA function of AQP0 could be crucial to establish lens refractive index gradient (RING). However, there is a lack of in vivo data to corroborate the role of AQP0 as a fiber CTCA molecule which is critical for creating lens RING. The present investigation is undertaken to gather in vivo evidence for the involvement of AQP0 in developing lens RING. Lenses of wild type (WT) mouse, AQP0 knockout (heterozygous, AQP0{sup +/−}) and AQP0 knockout lens transgenically expressing AQP1 (heterozygous AQP0{sup +/−}/AQP1{sup +/−}) mouse models were used for the study. Data on AQP0 protein profile of intact and N- and/or C-terminal cleaved AQP0 in the lens by MALDI-TOF mass spectrometry and SDS–PAGE revealed that outer cortex fiber cells have only intact AQP0 of ∼28 kDa, inner cortical and outer nuclear fiber cells have both intact and cleaved forms, and inner nuclear fiber cells have only cleaved forms (∼26–24 kDa). Knocking out of 50% of AQP0 protein caused light scattering, spherical aberration (SA) and cataract. Restoring the lost fiber cell membrane water permeability (P{sub f}) by transgene AQP1 did not reinstate complete lens transparency and the mouse lenses showed light scattering and SA

Freeform aberrations in phase space: an example.

Science.gov (United States)

Babington, James

2017-06-01

We consider how optical propagation and aberrations of freeform systems can be formulated in phase space. As an example system, a freeform prism is analyzed and discussed. Symmetry considerations and their group theory descriptions are given some importance. Numerical aberrations are also highlighted and put into the context of the underlying aberration theory.

Spherical aberrations of human astigmatic corneas.

Science.gov (United States)

Zhao, Huawei; Dai, Guang-Ming; Chen, Li; Weeber, Henk A; Piers, Patricia A

2011-11-01

To evaluate whether the average spherical aberration of human astigmatic corneas is statistically equivalent to human nonastigmatic corneas. Spherical aberrations of 445 astigmatic corneas prior to laser vision correction were retrospectively investigated to determine Zernike coefficients for central corneal areas 6 mm in diameter using CTView (Sarver and Associates). Data were divided into groups according to cylinder power (0.01 to 0.25 diopters [D], 0.26 to 0.75 D, 0.76 to 1.06 D, 1.07 to 1.53 D, 1.54 to 2.00 D, and >2.00 D) and according to age by decade. Spherical aberrations were correlated with age and astigmatic power among groups and the entire population. Statistical analyses were conducted, and P.05 for all tested groups). Mean spherical aberration of astigmatic corneas was not correlated significantly with cylinder power or age (P>.05). Spherical aberrations are similar to those of nonastigmatic corneas, permitting the use of these additional data in the design of aspheric toric intra-ocular lenses. Copyright 2011, SLACK Incorporated.

Whole eye wavefront aberrations in Mexican male subjects.

Science.gov (United States)

Cantú, Roberto; Rosales, Marco A; Tepichín, Eduardo; Curioca, Andrée; Montes, Victor; Bonilla, Julio

2004-01-01

To analyze the characteristics, incidence, and appearance of wavefront aberrations in undilated, normal, unoperated eyes. Eighty-eight eyes of 44 healthy male Mexican subjects (mean age 25.32 years, range 18 to 36 yr) were divided into three groups based on uncorrected visual acuity of greater than or equal to 20/20, 20/30, or 20/40. UCVA measurements were obtained using an Acuity Max computer screen chart. Wavefront aberrations were measured with the Nidek OPD-Scan ARK 10000, Ver. 1.11b. All measurements were carried out at the same center by the same technician during a single session, following manufacturer instructions. Background illumination was 3 Lux. Wavefront aberration measurements for each group were statistically analyzed using StatView; an average eye was characterized and the resulting aberrations were simulated using MATLAB. We obtained wavefront aberration maps for the 20/20 undilated normal unoperated eyes for total, low, and high order aberration coefficients. Wavefront maps for right eyes were practically the same as those for left eyes. Higher aberrations did not contribute substantially to total wavefront analysis. Average aberrations of this "normal eye" will be used as criteria to decide the necessity of wavefront-guided ablation in our facilities. We will focus on the nearly zero average of high order aberrations in this normal whole eye as a reference to be matched.

Measuring and correcting aberrations of a cathode objective lens

International Nuclear Information System (INIS)

Tromp, R.M.

2011-01-01

In this paper I discuss several theoretical and practical aspects related to measuring and correcting the chromatic and spherical aberrations of a cathode objective lens as used in Low Energy Electron Microscopy (LEEM) and Photo Electron Emission Microscopy (PEEM) experiments. Special attention is paid to the various components of the cathode objective lens as they contribute to chromatic and spherical aberrations, and affect practical methods for aberration correction. This analysis has enabled us to correct a LEEM instrument for the spherical and chromatic aberrations of the objective lens. -- Research highlights: → Presents a comprehensive theory of the relation between chromatic aberration and lens current in a cathode objective lens. → Presents practical methods for measuring both spherical and chromatic aberrations of a cathode objective lens. → Presents measurements of these aberrations in good agreement with theory. → Presents practical methods for measuring and correcting these aberrations with an electron mirror.

A novel approach to brachycephalic syndrome. 3. Isolated laser-assisted turbinectomy of caudal aberrant turbinates (CAT LATE).

Science.gov (United States)

Schuenemann, Riccarda; Pohl, Sabine; Oechtering, Gerhard U

2017-01-01

To describe isolated laser-assisted turbinectomy of caudal aberrant turbinates (CAT LATE) as a new minimally invasive surgical procedure for the treatment of brachycephalic dogs with obstructing caudal aberrant turbinates (CAT). Prospective clinical study. Brachycephalic dogs (24 Pugs, 1 English Bulldog) with CAT but adequate air spaces between the lamellae of the nonobstructing ventral nasal concha. A rhinoscopically guided diode laser fiber introduced from anterior was used to dissect CAT within the nasopharyngeal meatus, while leaving the intranasal turbinates intact. Small grasping forceps were used to extract the dissected CAT from anterior or to push it through the nasopharyngeal meatus for extraction from posterior. Isolated CAT LATE was successfully performed on 32 CAT in 25 dogs. Intranasally applied xylometazoline helped shrink the ventral concha, making the approach and extraction easier. Minor bleeding was the only complication observed. It is possible to remove CAT with endoscopically applied diode-laser energy while leaving the nonobstructing ventral nasal concha intact. © 2017 The American College of Veterinary Surgeons.

Chromosomal aberrations in ore miners of Slovakia

International Nuclear Information System (INIS)

Beno, M.; Vladar, M.; Nikodemova, D.; Vicanova, M.; Durcik, M.

1998-01-01

A pilot study was performed in which the incidence of chromosomal aberrations in lymphocytes of miners in ore mines located in Central Slovakia was monitored and related to lifetime underground radon exposure and to lifetime smoking. The conclusions drawn from the results of the study were as follows: the counts of chromosomal aberrations in lymphocytes of miners were significantly higher than in an age matched control group of white-collar staff; the higher counts of chromosomal aberrations could be ascribed to underground exposure of miners and to smoking; a dependence of chromosomal aberration counts on the exposure to radon could not be assessed. (A.K.)

Aberration studies and computer algebra

International Nuclear Information System (INIS)

Hawkes, P.W.

1981-01-01

The labour of calculating expressions for aberration coefficients is considerably lightened if a computer algebra language is used to perform the various substitutions and expansions involved. After a brief discussion of matrix representations of aberration coefficients, a particular language, which has shown itself to be well adapted to particle optics, is described and applied to the study of high frequency cavity lenses. (orig.)

Theoretical investigation of aberrations upon ametropic human eyes

Science.gov (United States)

Tan, Bo; Chen, Ying-Ling; Lewis, J. W. L.; Baker, Kevin

2003-11-01

The human eye aberrations are important for visual acuity and ophthalmic diagnostics and surgical procedures. Reported monochromatic aberration data of the normal 20/20 human eyes are scarce. There exist even fewer reports of the relation between ametropic conditions and aberrations. We theoretically investigate the monochromatic and chromatic aberrations of human eyes for refractive errors of -10 to +10 diopters. Schematic human eye models are employed using optical design software for axial, index, and refractive types of ametropia.

Flow cytogenetics: progress toward chromosomal aberration detection

International Nuclear Information System (INIS)

Carrano, A.V.; Gray, J.W.; Van Dilla, M.A.

1977-01-01

Using clonal derivatives of the Chinese hamster M3-1 cell line, we demonstrate the potential of flow systems to karyotype homogeneous aberrations (aberrations which are identical and present in every cell) and to detect heterogeneous aberrations (aberrations which occur randomly in a population and are not identical in every cell). Flow cytometry (FCM) of ethidium bromide stained isolated chromosomes from clone 650A of the M3-1 cells distinguishes nine chromosome types from the fourteen present in the actual karyotype. X-irradiation of this parent 650A clone produced two sub-clones with an altered flow karyotype, that is, their FCM distributions were characterized by the addition of new peaks and alterations in area under existing peaks. From the relative DNA content and area for each peak, as determined by computer analysis, we predicted that each clone had undergone a reciprocal translocation involving chromosomes from two peaks. This prediction was confirmed by Giemsa-banding the metaphase cells. Heterogeneous aberrations are reflected in the flow karyotype as an increase in background, that is, an increase in area underlying the chromosome peaks. This increase is dose dependent but, as yet, the sample variability has been too large for quantitative analysis. Flow sorting of the valleys between chromosome peaks produces enriched fractions of aberrant chromosomes for visual analysis. These approaches are potentially applicable to the analysis of chromsomal aberrations induced by environmental contaminants

Aberration-corrected STEM: current performance and future directions

Energy Technology Data Exchange (ETDEWEB)

Nellist, P D [Department of Physics, University of Dublin, Trinity College, Dublin 2 (Ireland); Chisholm, M F [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Lupini, A R [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Borisevich, A [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Jr, W H Sides [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Pennycook, S J [Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 (United States); Dellby, N [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Keyse, R [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Krivanek, O L [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Murfitt, M F [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Szilagyi, Z S [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States)

2006-02-22

Through the correction of spherical aberration in the scanning transmission electron microscope (STEM), the resolving of a 78 pm atomic column spacing has been demonstrated along with information transfer to 61 pm. The achievement of this resolution required careful control of microscope instabilities, parasitic aberrations and the compensation of uncorrected, higher order aberrations. Many of these issues are improved in a next generation STEM fitted with a new design of aberration corrector, and an initial result demonstrating aberration correction to a convergence semi-angle of 40 mrad is shown. The improved spatial resolution and beam convergence allowed for by such correction has implications for the way in which experiments are performed and how STEM data should be interpreted.

Nodal aberration theory for wild-filed asymmetric optical systems

Science.gov (United States)

Chen, Yang; Cheng, Xuemin; Hao, Qun

2016-10-01

Nodal Aberration Theory (NAT) was used to calculate the zero field position in Full Field Display (FFD) for the given aberration term. Aiming at wide-filed non-rotational symmetric decentered optical systems, we have presented the nodal geography behavior of the family of third-order and fifth-order aberrations. Meanwhile, we have calculated the wavefront aberration expressions when one optical element in the system is tilted, which was not at the entrance pupil. By using a three-piece-cellphone lens example in optical design software CodeV, the nodal geography is testified under several situations; and the wavefront aberrations are calculated when the optical element is tilted. The properties of the nodal aberrations are analyzed by using Fringe Zernike coefficients, which are directly related with the wavefront aberration terms and usually obtained by real ray trace and wavefront surface fitting.

Exclusive photorelease of signalling lipids at the plasma membrane

Czech Academy of Sciences Publication Activity Database

Nadler, A.; Yushchenko, Dmytro A.; Müller, R.; Stein, F.; Feng, S.; Mulle, C.; Carta, M.; Schultz, C.

2015-01-01

Roč. 6, Dec (2015), 10056/1-10056/10 ISSN 2041-1723 Institutional support: RVO:61388963 Keywords : pancreatic beta-cells * mossy fiber boutons * arachidonic acid Subject RIV: CC - Organic Chemistry Impact factor: 11.329, year: 2015 http://www.nature.com/ncomms/2015/151221/ncomms10056/full/ncomms10056.html

Adaptive aberration correction using a triode hyperbolic electron mirror

International Nuclear Information System (INIS)

Fitzgerald, J.P.S.; Word, R.C.; Koenenkamp, R.

2011-01-01

A converging electron mirror can be used to compensate spherical and chromatic aberrations in an electron microscope. This paper presents an analytical solution to a novel triode (three electrode) hyperbolic mirror as an improvement to the well-known diode (two electrode) hyperbolic mirror for aberration correction. A weakness of the diode mirror is a lack of flexibility in changing the chromatic and spherical aberration coefficients independently without changes in the mirror geometry. In order to remove this limitation, a third electrode can be added. We calculate the optical properties of the resulting triode mirror analytically on the basis of a simple model field distribution. We present the optical properties-the object/image distance, z 0 , and the coefficients of spherical and chromatic aberration, C s and C c , of both mirror types from an analysis of electron trajectories in the mirror field. From this analysis, we demonstrate that while the properties of both designs are similar, the additional parameters in the triode mirror improve the range of aberration that can be corrected. The triode mirror is also able to provide a dynamic adjustment range of chromatic aberration for fixed spherical aberration and focal length, or any permutation of these three parameters. While the dynamic range depends on the values of aberration correction needed, a nominal 10% tuning range is possible for most configurations accompanied by less than 1% change in the other two properties. -- Highlights: → Electrostatic aberration correction for chromatic and spherical aberration in electron optics. → Simultaneous correction of spherical and chromatic aberrations over a wide, adjustable range. → Analytic and quantitative description of correction parameters.

Rooting Out Aberrant Behavior in Training.

Science.gov (United States)

Kokalis, Jerry, Jr.; Paquin, Dave

1989-01-01

Discusses aberrant, or disruptive, behavior in an industrial/business, classroom-based, instructor-led training setting. Three examples of aberrant behavior are described, typical case studies are provided for each, and preventive (long-term) and corrective (on-the-spot) strategies for dealing with the problems are discussed. (LRW)

The correction of electron lens aberrations

Energy Technology Data Exchange (ETDEWEB)

Hawkes, P.W., E-mail: peter.hawkes@cemes.fr

2015-09-15

The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. - Highlights: • Geometrical aberration correction. • Chromatic aberration correction. • 50 pm resolution. • High-resolution electron energy-loss spectroscopy. • Extensive bibliographies.

The correction of electron lens aberrations

International Nuclear Information System (INIS)

Hawkes, P.W.

2015-01-01

The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. - Highlights: • Geometrical aberration correction. • Chromatic aberration correction. • 50 pm resolution. • High-resolution electron energy-loss spectroscopy. • Extensive bibliographies

Morphological Constraints on Cerebellar Granule Cell Combinatorial Diversity.

Science.gov (United States)

Gilmer, Jesse I; Person, Abigail L

2017-12-13

Combinatorial expansion by the cerebellar granule cell layer (GCL) is fundamental to theories of cerebellar contributions to motor control and learning. Granule cells (GrCs) sample approximately four mossy fiber inputs and are thought to form a combinatorial code useful for pattern separation and learning. We constructed a spatially realistic model of the cerebellar GCL and examined how GCL architecture contributes to GrC combinatorial diversity. We found that GrC combinatorial diversity saturates quickly as mossy fiber input diversity increases, and that this saturation is in part a consequence of short dendrites, which limit access to diverse inputs and favor dense sampling of local inputs. This local sampling also produced GrCs that were combinatorially redundant, even when input diversity was extremely high. In addition, we found that mossy fiber clustering, which is a common anatomical pattern, also led to increased redundancy of GrC input combinations. We related this redundancy to hypothesized roles of temporal expansion of GrC information encoding in service of learned timing, and we show that GCL architecture produces GrC populations that support both temporal and combinatorial expansion. Finally, we used novel anatomical measurements from mice of either sex to inform modeling of sparse and filopodia-bearing mossy fibers, finding that these circuit features uniquely contribute to enhancing GrC diversification and redundancy. Our results complement information theoretic studies of granule layer structure and provide insight into the contributions of granule layer anatomical features to afferent mixing. SIGNIFICANCE STATEMENT Cerebellar granule cells are among the simplest neurons, with tiny somata and, on average, just four dendrites. These characteristics, along with their dense organization, inspired influential theoretical work on the granule cell layer as a combinatorial expander, where each granule cell represents a unique combination of inputs

Third-rank chromatic aberrations of electron lenses.

Science.gov (United States)

Liu, Zhixiong

2018-02-01

In this paper the third-rank chromatic aberration coefficients of round electron lenses are analytically derived and numerically calculated by Mathematica. Furthermore, the numerical results are cross-checked by the differential algebraic (DA) method, which verifies that all the formulas for the third-rank chromatic aberration coefficients are completely correct. It is hoped that this work would be helpful for further chromatic aberration correction in electron microscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

Medial Auditory Thalamic Stimulation as a Conditioned Stimulus for Eyeblink Conditioning in Rats

Science.gov (United States)

Campolattaro, Matthew M.; Halverson, Hunter E.; Freeman, John H.

2007-01-01

The neural pathways that convey conditioned stimulus (CS) information to the cerebellum during eyeblink conditioning have not been fully delineated. It is well established that pontine mossy fiber inputs to the cerebellum convey CS-related stimulation for different sensory modalities (e.g., auditory, visual, tactile). Less is known about the…

The Distribution of Chromosomal Aberrations in Human Cells Predicted by a Generalized Time-Dependent Model of Radiation-Induced Formation of Aberrations

Science.gov (United States)

Ponomarev, Artem L.; George, K.; Cucinotta, F. A.

2011-01-01

New experimental data show how chromosomal aberrations for low- and high-LET radiation are dependent on DSB repair deficiencies in wild-type, AT and NBS cells. We simulated the development of chromosomal aberrations in these cells lines in a stochastic track-structure-dependent model, in which different cells have different kinetics of DSB repair. We updated a previously formulated model of chromosomal aberrations, which was based on a stochastic Monte Carlo approach, to consider the time-dependence of DSB rejoining. The previous version of the model had an assumption that all DSBs would rejoin, and therefore we called it a time-independent model. The chromosomal-aberrations model takes into account the DNA and track structure for low- and high-LET radiations, and provides an explanation and prediction of the statistics of rare and more complex aberrations. We compared the program-simulated kinetics of DSB rejoining to the experimentally-derived bimodal exponential curves of the DSB kinetics. We scored the formation of translocations, dicentrics, acentric and centric rings, deletions, and inversions. The fraction of DSBs participating in aberrations was studied in relation to the rejoining time. Comparisons of simulated dose dependence for simple aberrations to the experimental dose-dependence for HF19, AT and NBS cells will be made.

Chromosome aberrations in pesticide-exposed greenhouse workers

DEFF Research Database (Denmark)

Lander, B F; Knudsen, Lisbeth E.; Gamborg, M O

2000-01-01

OBJECTIVES: The aim of this study was to investigate the possibility of subtoxic exposure to pesticides causing chromosome aberrations in greenhouse workers. METHODS: In a cross-sectional and prospective study design chromosome aberration frequencies in cultured lymphocytes were examined for 116...... greenhouse workers exposed to a complex mixture of almost 50 insecticides, fungicides, and growth regulators and also for 29 nonsmoking, nonpesticide-exposed referents. RESULTS: The preseason frequencies of chromosome aberrations were slightly but not statistically significantly elevated for the greenhouse...... workers when they were compared with the referents. After a summer season of pesticide spraying in the greenhouses, the total frequencies of cells with chromosome aberrations were significantly higher than in the preseason samples (P=0.02) and also higher than for the referents (P=0.05). This finding...

Aberration-free intraocular lenses - What does this really mean?

Science.gov (United States)

Langenbucher, Achim; Schröder, Simon; Cayless, Alan; Eppig, Timo

2017-09-01

So-called aberration-free intraocular lenses (IOLs) are well established in modern cataract surgery. Usually, they are designed to perfectly refract a collimated light beam onto the focal point. We show how much aberration can be expected with such an IOL in a convergent light beam such as that found anterior to the human cornea. Additionally, the aberration in a collimated beam is estimated for an IOL that has no aberrations in the convergent beam. The convergent beam is modelled as the pencil of rays corresponding to the spherical wavefront resulting from a typical corneal power of 43m -1 . The IOLs are modelled as infinitely thin phase plates with 20m -1 optical power placed 5mm behind the cornea. Their aberrations are reported in terms of optical path length difference and longitudinal spherical aberration (LSA) of the marginal rays, as well as nominal spherical aberration (SA) calculated based on a Zernike representation of the wavefront-error at the corneal plane within a 6mm aperture. The IOL designed to have no aberrations in a collimated light beam has an optical path length difference of -1.8μm, and LSA of 0.15m -1 in the convergent beam of a typical eye. The corresponding nominal SA is 0.065μm. The IOL designed to have no aberrations in a convergent light beam has an optical path length difference of 1.8μm, and LSA of -0.15m -1 in the collimated beam. An IOL designed to have no aberrations in a collimated light beam will increase the SA of a patient's eye after implantation. Copyright © 2017. Published by Elsevier GmbH.

Image transfer with spatial coherence for aberration corrected transmission electron microscopes

International Nuclear Information System (INIS)

Hosokawa, Fumio; Sawada, Hidetaka; Shinkawa, Takao; Sannomiya, Takumi

2016-01-01

The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

Image transfer with spatial coherence for aberration corrected transmission electron microscopes

Energy Technology Data Exchange (ETDEWEB)

Hosokawa, Fumio, E-mail: hosokawa@bio-net.co.jp [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan); Sawada, Hidetaka [JEOL (UK) Ltd., JEOL House, Silver Court, Watchmead, Welwyn Garden City, Herts AL7 1LT (United Kingdom); Shinkawa, Takao [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Sannomiya, Takumi [Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan)

2016-08-15

The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

Effect of aberrations in human eye on contrast sensitivity function

Science.gov (United States)

Quan, Wei; Wang, Feng-lin; Wang, Zhao-qi

2011-06-01

The quantitative analysis of the effect of aberrations in human eye on vision has important clinical value in the correction of aberrations. The wave-front aberrations of human eyes were measured with the Hartmann-Shack wave-front sensor and modulation transfer function (MTF) was computed from the wave-front aberrations. Contrast sensitivity function (CSF) was obtained from MTF and the retinal aerial image modulation (AIM). It is shown that the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations deteriorate contrast sensitivity function. When the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations are corrected high contrast sensitivity function can be obtained.

Chromosome aberration analysis for biological dosimetry: a review

International Nuclear Information System (INIS)

Paul, S.F.D.; Venkatachalam, P.; Jeevanram, R.K.

1996-01-01

Among various biological dosimetry techniques, dicentric chromosome aberration method appears to be the method of choice in analysing accidental radiation exposure in most of the laboratories. The major advantage of this method is its sensitivity as the number of dicentric chromosomes present in control population is too small and more importantly radiation induces mainly dicentric chromosome aberration among unstable aberration. This report brings out the historical development of various cytogenetic methods, the basic structure of DNA, chromosomes and different forms of chromosome aberrations. It also highlights the construction of dose-response curve for dicentric chromosome and its use in the estimation of radiation dose. (author)

Wave aberrations in rhesus monkeys with vision-induced ametropias

Science.gov (United States)

Ramamirtham, Ramkumar; Kee, Chea-su; Hung, Li-Fang; Qiao-Grider, Ying; Huang, Juan; Roorda, Austin; Smith, Earl L.

2007-01-01

The purpose of this study was to investigate the relationship between refractive errors and high-order aberrations in infant rhesus monkeys. Specifically, we compared the monochromatic wave aberrations measured with a Shack-Hartman wavefront sensor between normal monkeys and monkeys with vision-induced refractive errors. Shortly after birth, both normal monkeys and treated monkeys reared with optically induced defocus or form deprivation showed a decrease in the magnitude of high-order aberrations with age. However, the decrease in aberrations was typically smaller in the treated animals. Thus, at the end of the lens-rearing period, higher than normal amounts of aberrations were observed in treated eyes, both hyperopic and myopic eyes and treated eyes that developed astigmatism, but not spherical ametropias. The total RMS wavefront error increased with the degree of spherical refractive error, but was not correlated with the degree of astigmatism. Both myopic and hyperopic treated eyes showed elevated amounts of coma and trefoil and the degree of trefoil increased with the degree of spherical ametropia. Myopic eyes also exhibited a much higher prevalence of positive spherical aberration than normal or treated hyperopic eyes. Following the onset of unrestricted vision, the amount of high-order aberrations decreased in the treated monkeys that also recovered from the experimentally induced refractive errors. Our results demonstrate that high-order aberrations are influenced by visual experience in young primates and that the increase in high-order aberrations in our treated monkeys appears to be an optical byproduct of the vision-induced alterations in ocular growth that underlie changes in refractive error. The results from our study suggest that the higher amounts of wave aberrations observed in ametropic humans are likely to be a consequence, rather than a cause, of abnormal refractive development. PMID:17825347

Femtosecond filaments for rapid and flexible writing of Fiber-Bragg grating (Conference Presentation)

Science.gov (United States)

Ertorer, Erden; Haque, Moez; Li, Jianzhao; Herman, Peter R.

2017-03-01

Kerr-lens self-channelling of femtosecond laser light offers a novel high-aspect geometry for laser processing inside transparent materials. In glass materials, the laser filaments enable white-light continuum generation, scribing, nanochannel formation, and refractive index modification. In the present work, refractive index matching oils were applied around optical fiber to eliminate astigmatic aberration and thereby form highly symmetric and uniform filaments selectively in the cladding or core waveguide of standard single-mode optical fibre (SMF-28). Under tight focusing, long filaments exceeding 20 um length were formed with single pulses to sub-micron diameter. Arrays of 0.5 um spaced filaments are verified by formation of strong fiber Bragg gratings (FBGs). Flexible positioning of the filament arrays within the fiber core offers wide scope for coupling to cladding and radiation modes and creating new types of in-fibre optical devices.

The Art of Optical Aberrations

Science.gov (United States)

Wylde, Clarissa Eileen Kenney

Art and optics are inseparable. Though seemingly opposite disciplines, the combination of art and optics has significantly impacted both culture and science as they are now known. As history has run its course, in the sciences, arts, and their fruitful combinations, optical aberrations have proved to be a problematic hindrance to progress. In an effort to eradicate aberrations the simple beauty of these aberrational forms has been labeled as undesirable and discarded. Here, rather than approach aberrations as erroneous, these beautiful forms are elevated to be the photographic subject in a new body of work, On the Bright Side. Though many recording methods could be utilized, this work was composed on classic, medium-format, photographic film using white-light, Michelson interferometry. The resulting images are both a representation of the true light rays that interacted on the distorted mirror surfaces (data) and the artist's compositional eye for what parts of the interferogram are chosen and displayed. A detailed description of the captivating interdisciplinary procedure is documented and presented alongside the final artwork, CCD digital reference images, and deformable mirror contour maps. This alluring marriage between the arts and sciences opens up a heretofore minimally explored aspect of the inextricable art-optics connection. It additionally provides a fascinating new conversation on the importance of light and optics in photographic composition.

Aberration design of zoom lens systems using thick lens modules.

Science.gov (United States)

Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

2014-12-20

A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

Third-order monochromatic aberrations via Fermat's principle

International Nuclear Information System (INIS)

Marasco, A.; Romano, A.

2006-01-01

By Fermat's principle and particular optical paths, which are not rays, a new aberration function is introduced. This function allows to derive, without resorting to the whole Hamiltonian formalism, the third-order geometrical aberrations of an optical system with a symmetry of revolution

Catadioptric aberration correction in cathode lens microscopy

Energy Technology Data Exchange (ETDEWEB)

Tromp, R.M. [IBM T.J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598 (United States); Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

2015-04-15

In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed.

Radiation-induced chromosome aberrations in the rat peripheral blood

International Nuclear Information System (INIS)

Ziemba-Zoltowska, B.; Bocian, E.; Radwan, I.; Rosiek, O.; Sablinski, J.

1978-01-01

Chromosome aberrations in rat lymphocytes of peripheral blood after X (in vitro and in vivo) and 3 H tritiated water (in vivo) irradiations were studied. The yield of chromosome aberrations after in vivo and in vitro exposure to X-rays was similar. The frequency of chromosome aberrations three weeks after exposure to X-rays and soon after irradiation was practically on the same level. The yield of chromosome aberrations determined three weeks after injection with tritiated water or X-rays exposure was similar. (author)

Chromosomal aberrations in bone marrow of continuously irradiated rats

Energy Technology Data Exchange (ETDEWEB)

Chlebosky, O; Praslicka, M; Chlebovska, K [Univerzita P.J. Safarika, Kosice (Czechoslovakia). Prirodovedecka Fakulta

1975-01-01

Research on chromosomal aberrations of the bone marrow in continuously irradiated rats showed that chromosomal aberrations are a highly sensitive indicator of radiation injury. An increase in the chromosomal aberration frequency was already found on the 5th day at daily doses of 0.5 R, i.e. a 12% increase at a total dose of 25 R. In the steady-state stage at daily doses of 0.5; 1; 2.5 R, the number of chromosomal aberrations stabilized at values of about 20%; at daily doses of 5 and 10 R at values of 30.=., at daily doses of 53 R at 45%, at a daily dose of 82.5 R, the number of chromosomal aberrations increased to 55%.

Aberration-corrected STEM/TEM imaging at 15 kV

International Nuclear Information System (INIS)

Sasaki, Takeo; Sawada, Hidetaka; Hosokawa, Fumio; Sato, Yuta; Suenaga, Kazu

2014-01-01

The performance of aberration-corrected (scanning) transmission electron microscopy (S/TEM) at an accelerating voltage of 15 kV was evaluated in a low-voltage microscope equipped with a cold-field emission gun and a higher-order aberration corrector. Aberrations up to the fifth order were corrected by the aberration measurement and auto-correction system using the diffractogram tableau method in TEM and Ronchigram analysis in STEM. TEM observation of nanometer-sized particles demonstrated that aberrations up to an angle of 50 mrad were compensated. A TEM image of Si[110] exhibited lattice fringes with a spacing of 0.192 nm, and the power spectrum of the image showed spots corresponding to distances of 0.111 nm. An annular dark-field STEM image of Si[110] showed lattice fringes of (111) and (22¯0) planes corresponding to lattice distances of 0.314 nm and 0.192 nm, respectively. At an accelerating voltage of 15 kV, the developed low-voltage microscope achieved atomic-resolution imaging with a small chromatic aberration and a large uniform phase. - Highlights: • Aberration-corrected STEM/TEM imaging at 15 kV demonstrated lattice fringes of Si[110] single crystal with a spacing of 0.192 nm. • To achieve this performance at a lower accelerating voltage, uniform phase area over 50 mrad is mandatory in Ronchigram and Diffractogram tableau. • This means a higher-order aberration of six-fold astigmatism should be compensated. • In addition, decreasing the effect of chromatic aberration plays an important role for improving the performance of linear scattering component at 15 kV TEM

Estimation of dose from chromosome aberration rate

International Nuclear Information System (INIS)

Li Deping

1990-01-01

The methods and skills of evaluating dose from correctly scored shromsome aberration rate are presented, and supplemented with corresponding BASIC computer code. The possibility and preventive measures of excessive probability of missing score of the aberrations in some of the current routine score methods are discussed. The use of dose-effect relationship with exposure time correction factor G in evaluating doses and their confidence intervals, dose estimation in mixed n-γ exposure, and identification of high by nonuniform acute exposure to low LET radiation and its dose estimation are discussed in more detail. The difference of estimated dose due to whether the interaction between subleisoms produced by n and γ have been taken into account is examined. In fitting the standard dose-aberration rate curve, proper weighing of experiment points and comparison with commonly accepted values are emphasised, and the coefficient of variation σ y √y of the aberration rate y as a function of dose and exposure time is given. In appendix I and II, the dose-aberration rate formula is derived from dual action theory, and the time variation of subleisom is illustrated and in appendix III, the estimation of dose from scores of two different types of aberrations (of other related score) is illustrated. Two computer codes are given in appendix IV, one is a simple code, the other a complete code, including the fitting of standard curve. the skills of using compressed data storage, and the production of simulated 'data ' for testing the curve fitting procedure are also given

Aberration of a negative ion beam caused by space charge effect

International Nuclear Information System (INIS)

Miyamoto, K.; Wada, S.; Hatayama, A.

2010-01-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Wada, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2010-02-15

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect.

Science.gov (United States)

Miyamoto, K; Wada, S; Hatayama, A

2010-02-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberrant regeneration of the third cranial nerve.

Science.gov (United States)

Shrestha, U D; Adhikari, S

2012-01-01

Aberrant regeneration of the third cranial nerve is most commonly due to its damage by trauma. A ten-month old child presented with the history of a fall from a four-storey building. She developed traumatic third nerve palsy and eventually the clinical features of aberrant regeneration of the third cranial nerve. The adduction of the eye improved over time. She was advised for patching for the strabismic amblyopia as well. Traumatic third nerve palsy may result in aberrant regeneration of the third cranial nerve. In younger patients, motility of the eye in different gazes may improve over time. © NEPjOPH.

Transverse correlation vanishing due to phase aberrations

CSIR Research Space (South Africa)

Godin, T

2011-06-01

Full Text Available of the effects of each aberration on the ratio Sp ?? / , the following condition are imposed: 0max3max2max1 )()()( ??????? === . (9) It is assumed that the phase aberration is set in the beam-waist plane of radius mmW 5.10 = . Arbitrarily, the value... of max? is fixed to twice the incident beam width, 0max 2W=? , where the intensity is only 0.03% of the on-axis value. In the following we will express the aberration 0? in number of equivalent wavelengths given by the ratio )2/(00 pi...

Frequencies of chromosome aberration on radiation workers

International Nuclear Information System (INIS)

Yanti Lusiyanti; Zubaidah Alatas

2016-01-01

Radiation exposure of the body can cause damage to the genetic material in cells (cytogenetic) in the form of changes in the structure or chromosomal aberrations in peripheral blood lymphocytes. Chromosomal aberrations can be unstable as dicentric and ring chromosomes, and is stable as translocation. Dicentric chromosome is the gold standard biomarker due to radiation exposure, and chromosome translocation is a biomarker for retrospective biodosimetry. The aim of this studi is to conduct examination of chromosomal aberrations in the radiation worker to determine the potential damage of cell that may arise due to occupational radiation exposure. The examination have been carried out on blood samples from 55 radiation workers in the range of 5-30 year of service. Chromosome aberration frequency measurement starts with blood sampling, culturing, harvesting, slide preparations, and lymphocyte chromosome staining with Giemsa and painting with Fluorescence In Situ Hybridization (FISH) technique. The results showed that chromosomal translocations are not found in blood samples radiation workers and dicentric chromosomes found only on 2 blood samples of radiation workers with a frequency of 0.001/cell. The frequency of chromosomal aberrations in the blood cells such workers within normal limits and this means that the workers have been implemented a radiation safety aspects very well. (author)

Visuomotor cerebellum in human and nonhuman primates.

Science.gov (United States)

Voogd, Jan; Schraa-Tam, Caroline K L; van der Geest, Jos N; De Zeeuw, Chris I

2012-06-01

In this paper, we will review the anatomical components of the visuomotor cerebellum in human and, where possible, in non-human primates and discuss their function in relation to those of extracerebellar visuomotor regions with which they are connected. The floccular lobe, the dorsal paraflocculus, the oculomotor vermis, the uvula-nodulus, and the ansiform lobule are more or less independent components of the visuomotor cerebellum that are involved in different corticocerebellar and/or brain stem olivocerebellar loops. The floccular lobe and the oculomotor vermis share different mossy fiber inputs from the brain stem; the dorsal paraflocculus and the ansiform lobule receive corticopontine mossy fibers from postrolandic visual areas and the frontal eye fields, respectively. Of the visuomotor functions of the cerebellum, the vestibulo-ocular reflex is controlled by the floccular lobe; saccadic eye movements are controlled by the oculomotor vermis and ansiform lobule, while control of smooth pursuit involves all these cerebellar visuomotor regions. Functional imaging studies in humans further emphasize cerebellar involvement in visual reflexive eye movements and are discussed.

Ocular higher-order aberrations in a school children population

Directory of Open Access Journals (Sweden)

George Papamastorakis

2015-04-01

Conclusions: Differences in the low levels of ocular spherical aberration in young children possibly reflect differences in lenticular spherical aberration and relate to the gradient refractive index of the lens. The evaluation of spherical aberration at certain stages of eye growth may help to better understand the underlying mechanisms of myopia development.

Fifth-order canonical geometric aberration analysis of electrostatic round lenses

CERN Document Server

Liu Zhi Xiong

2002-01-01

In this paper the fifth-order canonical geometric aberration patterns are analyzed and a numerical example is given on the basis of the analytical expressions of fifth-order aberration coefficients derived in the present work. The fifth-order spherical aberration, astigmatism and field curvature, and distortion are similar to the third-order ones and the fifth-order coma is slightly different. Besides, there are two more aberrations which do not exist in the third-order aberration: they are peanut aberration and elliptical coma in accordance with their shapes. In the numerical example, by using a cross-check of the calculated coefficients with those computed through the differential algebraic method, it has been verified that all the expressions are correct and the computational results are reliable with high precision.

Chromosomal aberrations induced by alpha particles

International Nuclear Information System (INIS)

Guerrero C, C.; Brena V, M.

2005-01-01

The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

Dendrites of cerebellar granule cells correctly recognize their target axons for synaptogenesis in vitro.

Science.gov (United States)

Ito, Shoko; Takeichi, Masatoshi

2009-08-04

Neural circuits are generated by precisely ordered synaptic connections among neurons, and this process is thought to rely on the ability of neurons to recognize specific partners. However, it is also known that neurons promiscuously form synapses with nonspecific partners, in particular when cultured in vitro, causing controversies about neural recognition mechanisms. Here we reexamined whether neurons can or cannot select particular partners in vitro. In the cerebellum, granule cell (GC) dendrites form synaptic connections specifically with mossy fibers, but not with climbing fibers. We cocultured GC neurons with pontine or inferior olivary axons, the major sources for mossy and climbing fibers, respectively, as well as with hippocampal axons as a control. The GC neurons formed synapses with pontine axons predominantly at the distal ends of their dendrites, reproducing the characteristic morphology of their synapses observed in vivo, whereas they failed to do so when combined with other axons. In the latter case, synaptic proteins could accumulate between axons and dendrites, but these synapses were randomly distributed throughout the contact sites, and also their synaptic vesicle recycling was anomalous. These observations suggest that GC dendrites can select their authentic partners for synaptogenesis even in vitro, forming the synapses with a GC-specific nature only with them.

Spherical aberration and other higher-order aberrations in the human eye : from summary wave-front analysis data to optical variables relevant to visual perception

NARCIS (Netherlands)

Jansonius, Nomdo M.

Wave-front analysis data from the human eye are commonly presented using the aberration coefficient c(4)(0) (primary spherical aberration) together with an overall measure of all higher-order aberrations. If groups of subjects are compared, however, the relevance of an observed difference cannot

Statistical estimation of ultrasonic propagation path parameters for aberration correction.

Science.gov (United States)

Waag, Robert C; Astheimer, Jeffrey P

2005-05-01

Parameters in a linear filter model for ultrasonic propagation are found using statistical estimation. The model uses an inhomogeneous-medium Green's function that is decomposed into a homogeneous-transmission term and a path-dependent aberration term. Power and cross-power spectra of random-medium scattering are estimated over the frequency band of the transmit-receive system by using closely situated scattering volumes. The frequency-domain magnitude of the aberration is obtained from a normalization of the power spectrum. The corresponding phase is reconstructed from cross-power spectra of subaperture signals at adjacent receive positions by a recursion. The subapertures constrain the receive sensitivity pattern to eliminate measurement system phase contributions. The recursion uses a Laplacian-based algorithm to obtain phase from phase differences. Pulse-echo waveforms were acquired from a point reflector and a tissue-like scattering phantom through a tissue-mimicking aberration path from neighboring volumes having essentially the same aberration path. Propagation path aberration parameters calculated from the measurements of random scattering through the aberration phantom agree with corresponding parameters calculated for the same aberrator and array position by using echoes from the point reflector. The results indicate the approach describes, in addition to time shifts, waveform amplitude and shape changes produced by propagation through distributed aberration under realistic conditions.

Long-term potentiation in hilar circuitry modulates gating by the dentate gyrus.

Science.gov (United States)

Wright, Brandon J; Jackson, Meyer B

2014-07-16

The dentate gyrus serves as a gateway to the hippocampus, filtering and processing sensory inputs as an animal explores its environment. The hilus occupies a strategic position within the dentate gyrus from which it can play a pivotal role in these functions. Inputs from dentate granule cells converge on the hilus, and excitatory hilar mossy cells redistribute these signals back to granule cells to transform a pattern of cortical input into a new pattern of output to the hippocampal CA3 region. Using voltage-sensitive dye to image electrical activity in rat hippocampal slices, we explored how long-term potentiation (LTP) of different excitatory synapses modifies the flow of information. Theta burst stimulation of the perforant path potentiated responses throughout the molecular layer, but left responses in the CA3 region unchanged. By contrast, theta burst stimulation of the granule cell layer potentiated responses throughout the molecular layer, as well as in the CA3 region. Theta burst stimulation of the granule cell layer potentiated CA3 responses not only to granule cell layer stimulation but also to perforant path stimulation. Potentiation of responses in the CA3 region reflected NMDA receptor-dependent LTP of upstream synapses between granule cells and mossy cells, with no detectable contribution from NMDA receptor-independent LTP of local CA3 mossy fiber synapses. Potentiation of transmission to the CA3 region required LTP in both granule cell→mossy cell and mossy cell→granule cell synapses. This bidirectional plasticity enables hilar circuitry to regulate the flow of information through the dentate gyrus and on to the hippocampus. Copyright © 2014 the authors 0270-6474/14/349743-11$15.00/0.

Higher order aberrations of the eye: Part one

Directory of Open Access Journals (Sweden)

Marsha Oberholzer

2016-06-01

Full Text Available This article is the first in a series of two articles that provide a comprehensive literature review of higher order aberrations (HOAs of the eye. The present article mainly explains the general principles of such HOAs as well as HOAs of importance, and the measuring apparatus used to measure HOAs of the eye. The second article in the series discusses factors contributing to variable results in measurements of HOAs of the eye. Keywords: Higher order aberrations; wavefront aberrations; aberrometer

Effect of spherical aberration on scintillations of Gaussian beams in atmospheric turbulence

International Nuclear Information System (INIS)

Ji, Xiaoling; Deng, Jinping

2014-01-01

The effect of spherical aberration on scintillations of Gaussian beams in weak, moderate and strong turbulence is studied using numerical simulation method. It is found that the effect of the negative spherical aberration on the on-axis scintillation index is quite different from that of the positive spherical aberration. In weak turbulence, the positive spherical aberration results in a decrease of the on-axis scintillation index on propagation, but the negative spherical aberration results in an increase of the on-axis scintillation index when the propagation distance is not large. In particular, in weak turbulence the negative spherical aberration may cause peaks of the on-axis scintillation index, and the peaks disappear in moderate and strong turbulence, which is explained in physics. The strong turbulence leads to less discrepancy among scintillations of Gaussian beams with and without spherical aberration. - Highlights: • In weak turbulence scintillations can be suppressed using positive spherical aberration. • In weak turbulence scintillations may be very large due to negative spherical aberration. • The effect of spherical aberration on scintillations is less with increasing of turbulence

Effect of spherical aberration on scintillations of Gaussian beams in atmospheric turbulence

Energy Technology Data Exchange (ETDEWEB)

Ji, Xiaoling, E-mail: jiXL100@163.com; Deng, Jinping

2014-07-18

The effect of spherical aberration on scintillations of Gaussian beams in weak, moderate and strong turbulence is studied using numerical simulation method. It is found that the effect of the negative spherical aberration on the on-axis scintillation index is quite different from that of the positive spherical aberration. In weak turbulence, the positive spherical aberration results in a decrease of the on-axis scintillation index on propagation, but the negative spherical aberration results in an increase of the on-axis scintillation index when the propagation distance is not large. In particular, in weak turbulence the negative spherical aberration may cause peaks of the on-axis scintillation index, and the peaks disappear in moderate and strong turbulence, which is explained in physics. The strong turbulence leads to less discrepancy among scintillations of Gaussian beams with and without spherical aberration. - Highlights: • In weak turbulence scintillations can be suppressed using positive spherical aberration. • In weak turbulence scintillations may be very large due to negative spherical aberration. • The effect of spherical aberration on scintillations is less with increasing of turbulence.

Influence of Misalignment on High-Order Aberration Correction for Normal Human Eyes

Science.gov (United States)

Zhao, Hao-Xin; Xu, Bing; Xue, Li-Xia; Dai, Yun; Liu, Qian; Rao, Xue-Jun

2008-04-01

Although a compensation device can correct aberrations of human eyes, the effect will be degraded by its misalignment, especially for high-order aberration correction. We calculate the positioning tolerance of correction device for high-order aberrations, and within what degree the correcting effect is better than low-order aberration (defocus and astigmatism) correction. With fixed certain misalignment within the positioning tolerance, we calculate the residual wavefront rms aberration of the first-6 to first-35 terms along with the 3rd-5th terms of aberrations corrected, and the combined first-13 terms of aberrations are also studied under the same quantity of misalignment. However, the correction effect of high-order aberrations does not meliorate along with the increase of the high-order terms under some misalignment, moreover, some simple combined terms correction can achieve similar result as complex combinations. These results suggest that it is unnecessary to correct too much the terms of high-order aberrations which are difficult to accomplish in practice, and gives confidence to correct high-order aberrations out of the laboratory.

Influence of Misalignment on High-Order Aberration Correction for Normal Human Eyes

International Nuclear Information System (INIS)

Hao-Xin, Zhao; Bing, Xu; Li-Xia, Xue; Yun, Dai; Qian, Liu; Xue-Jun, Rao

2008-01-01

Although a compensation device can correct aberrations of human eyes, the effect will be degraded by its misalignment, especially for high-order aberration correction. We calculate the positioning tolerance of correction device for high-order aberrations, and within what degree the correcting effect is better than low-order aberration (defocus and astigmatism) correction. With fixed certain misalignment within the positioning tolerance, we calculate the residual wavefront rms aberration of the first-6 to first-35 terms along with the 3rd-5th terms of aberrations corrected, and the combined first-13 terms of aberrations are also studied under the same quantity of misalignment. However, the correction effect of high-order aberrations does not meliorate along with the increase of the high-order terms under some misalignment, moreover, some simple combined terms correction can achieve similar result as complex combinations. These results suggest that it is unnecessary to correct too much the terms of high-order aberrations which are difficult to accomplish in practice, and gives confidence to correct high-order aberrations out of the laboratory

Possible mechanisms of chromosomal aberrations: VII. Comparative dynamics of sister chromatid disjunction and realization of radiation-induced chromosomal aberrations during mitosis

International Nuclear Information System (INIS)

Lebedeva, L.I.; Akhmamet'eva, E.M.

1994-01-01

An increase in radiation-induced chromosomal aberrations during c-metaphase sister chromatid disjunction was demonstrated in murine bone marrow cells exposed to a total γ-irradiation at 0.5 Gy. Caffeine (Cf) treatment during mitosis partially suppressed the chromatid disjunction rate and increased the number of radiation-induced aberrations in this mitosis. Nalidixic acid (NA) treatment of c-metaphase cells completely suppressed chromatid disjunction and the realization of induced aberrations. Topoisomerase 2 was assumed to be involved during mitosis in both processes

Chromosome aberration analysis based on a beta-binomial distribution

International Nuclear Information System (INIS)

Otake, Masanori; Prentice, R.L.

1983-10-01

Analyses carried out here generalized on earlier studies of chromosomal aberrations in the populations of Hiroshima and Nagasaki, by allowing extra-binomial variation in aberrant cell counts corresponding to within-subject correlations in cell aberrations. Strong within-subject correlations were detected with corresponding standard errors for the average number of aberrant cells that were often substantially larger than was previously assumed. The extra-binomial variation is accomodated in the analysis in the present report, as described in the section on dose-response models, by using a beta-binomial (B-B) variance structure. It is emphasized that we have generally satisfactory agreement between the observed and the B-B fitted frequencies by city-dose category. The chromosomal aberration data considered here are not extensive enough to allow a precise discrimination between competing dose-response models. A quadratic gamma ray and linear neutron model, however, most closely fits the chromosome data. (author)

Chromosome aberrations: plants to human and Feulgen to FISH

International Nuclear Information System (INIS)

Natarajan, A.T.

2005-01-01

Chromosome aberrations and their impact on human health have been recognized for a long time. In the 1950s, in India, studies on induced chromosome aberrations in plants were initiated by Swaminathan and his students. I trace here the impact of these initial studies on further developments in this field. The studies which were started in plants have been extended to mammals (including human) and the simple squash and solid staining have been improved by molecular cytogenetic techniques, thus enabling accurate identification and quantification of different types of chromosome aberrations. These studies have also thrown light on the mechanisms of chromosome aberration formation, especially following exposure to ionizing radiation. (author)

Radiation-induced cellular reproductive death and chromosome aberrations

International Nuclear Information System (INIS)

Bedford, J.S.; Mitchell, J.B.; Griggs, H.G.; Bender, M.A.

1978-01-01

If a major mode of cell killing by ionizing radiation is the death of cells containing visible chromosomal aberrations, as for example from anaphase-bridge formation at mitosis, then cells bearing such aberrations should be selectively eliminated from the population, resulting in an increased survival potential for the population remaining at each succeeding cell generation. Using synchronized V79B Chinese hamster cells, we measured the aberration frequency and the colony-forming ability of mitotic cells at each of the first three generations following irradiation in G1. Cells were resynchronized by mechanial harvest at each succeeding mitosis after irradiation in order to avoid mixing of generations in the cell population at later sampling times. As anticipated, the chromosome aberration frequencies decreased markedly from the first to the second and from the second to the third mitosis. The surviving fraction, however, was virtually the same for plating assays carried out immediately after irradiation, at the first, or at the second mitosis. The surviving fraction was significantly higher for cells reaching the third postirradiation mitosis. Survival and aberration frequencies were assayed again at approximately the fourteenth postirradiation division, by which time the irradiated and control populations were not significantly different

Theory of aberration fields for general optical systems with freeform surfaces.

Science.gov (United States)

Fuerschbach, Kyle; Rolland, Jannick P; Thompson, Kevin P

2014-11-03

This paper utilizes the framework of nodal aberration theory to describe the aberration field behavior that emerges in optical systems with freeform optical surfaces, particularly φ-polynomial surfaces, including Zernike polynomial surfaces, that lie anywhere in the optical system. If the freeform surface is located at the stop or pupil, the net aberration contribution of the freeform surface is field constant. As the freeform optical surface is displaced longitudinally away from the stop or pupil of the optical system, the net aberration contribution becomes field dependent. It is demonstrated that there are no new aberration types when describing the aberration fields that arise with the introduction of freeform optical surfaces. Significantly it is shown that the aberration fields that emerge with the inclusion of freeform surfaces in an optical system are exactly those that have been described by nodal aberration theory for tilted and decentered optical systems. The key contribution here lies in establishing the field dependence and nodal behavior of each freeform term that is essential knowledge for effective application to optical system design. With this development, the nodes that are distributed throughout the field of view for each aberration type can be anticipated and targeted during optimization for the correction or control of the aberrations in an optical system with freeform surfaces. This work does not place any symmetry constraints on the optical system, which could be packaged in a fully three dimensional geometry, without fold mirrors.

Aberrant internal carotid artery in the middle ear

Energy Technology Data Exchange (ETDEWEB)

Roh, Keun Tak; Kang, Hyun Koo [Dept. of Radiology, Seoul Veterans Hospital, Seoul (Korea, Republic of)

2014-10-15

The knowledge about the aberrant internal carotid artery (ICA) in the middle ear is essential for clinicians, because a misdiagnosis of the aberrant ICA could have serious consequences such as excessive aural bleeding during a middle ear surgery. A 38-year-old woman presented with tinnitus and hearing difficulties of the left ear that had started 5 years ago. During otoscopy, an anteroinferior bluish mass was seen in the tympanic space. Computed tomography and magnetic resonance imaging demonstrated a left-side aberrant ICA with bony dehiscence of the carotid canal in the middle ear and a reduced diameter of the tympanic ICA. Herein we report a case of an aberrant ICA in the middle ear. We also review the literature regarding this important vascular anomaly of the temporal bone which may lead to disastrous surgical complications.

Aberrant internal carotid artery in the middle ear

International Nuclear Information System (INIS)

Roh, Keun Tak; Kang, Hyun Koo

2014-01-01

The knowledge about the aberrant internal carotid artery (ICA) in the middle ear is essential for clinicians, because a misdiagnosis of the aberrant ICA could have serious consequences such as excessive aural bleeding during a middle ear surgery. A 38-year-old woman presented with tinnitus and hearing difficulties of the left ear that had started 5 years ago. During otoscopy, an anteroinferior bluish mass was seen in the tympanic space. Computed tomography and magnetic resonance imaging demonstrated a left-side aberrant ICA with bony dehiscence of the carotid canal in the middle ear and a reduced diameter of the tympanic ICA. Herein we report a case of an aberrant ICA in the middle ear. We also review the literature regarding this important vascular anomaly of the temporal bone which may lead to disastrous surgical complications.

Excitatory Synaptic Drive and Feedforward Inhibition in the Hippocampal CA3 Circuit Are Regulated by SynCAM 1.

Science.gov (United States)

Park, Kellie A; Ribic, Adema; Laage Gaupp, Fabian M; Coman, Daniel; Huang, Yuegao; Dulla, Chris G; Hyder, Fahmeed; Biederer, Thomas

2016-07-13

Select adhesion proteins control the development of synapses and modulate their structural and functional properties. Despite these important roles, the extent to which different synapse-organizing mechanisms act across brain regions to establish connectivity and regulate network properties is incompletely understood. Further, their functional roles in different neuronal populations remain to be defined. Here, we applied diffusion tensor imaging (DTI), a modality of magnetic resonance imaging (MRI), to map connectivity changes in knock-out (KO) mice lacking the synaptogenic cell adhesion protein SynCAM 1. This identified reduced fractional anisotropy in the hippocampal CA3 area in absence of SynCAM 1. In agreement, mossy fiber refinement in CA3 was impaired in SynCAM 1 KO mice. Mossy fibers make excitatory inputs onto postsynaptic specializations of CA3 pyramidal neurons termed thorny excrescences and these structures were smaller in the absence of SynCAM 1. However, the most prevalent targets of mossy fibers are GABAergic interneurons and SynCAM 1 loss unexpectedly reduced the number of excitatory terminals onto parvalbumin (PV)-positive interneurons in CA3. SynCAM 1 KO mice additionally exhibited lower postsynaptic GluA1 expression in these PV-positive interneurons. These synaptic imbalances in SynCAM 1 KO mice resulted in CA3 disinhibition, in agreement with reduced feedforward inhibition in this network in the absence of SynCAM 1-dependent excitatory drive onto interneurons. In turn, mice lacking SynCAM 1 were impaired in memory tasks involving CA3. Our results support that SynCAM 1 modulates excitatory mossy fiber inputs onto both interneurons and principal neurons in the hippocampal CA3 area to balance network excitability. This study advances our understanding of synapse-organizing mechanisms on two levels. First, the data support that synaptogenic proteins guide connectivity and can function in distinct brain regions even if they are expressed broadly

An aberrant precision account of autism.

Directory of Open Access Journals (Sweden)

Rebecca P Lawson

2014-05-01

Full Text Available Autism is a neurodevelopmental disorder characterised by problems with social-communication, restricted interests and repetitive behaviour. A recent and controversial article presented a compelling normative explanation for the perceptual symptoms of autism in terms of a failure of Bayesian inference (Pellicano and Burr, 2012. In response, we suggested that when Bayesian interference is grounded in its neural instantiation – namely, predictive coding – many features of autistic perception can be attributed to aberrant precision (or beliefs about precision within the context of hierarchical message passing in the brain (Friston et al., 2013. Here, we unpack the aberrant precision account of autism. Specifically, we consider how empirical findings – that speak directly or indirectly to neurobiological mechanisms – are consistent with the aberrant encoding of precision in autism; in particular, an imbalance of the precision ascribed to sensory evidence relative to prior beliefs.

Image based method for aberration measurement of lithographic tools

Science.gov (United States)

Xu, Shuang; Tao, Bo; Guo, Yongxing; Li, Gongfa

2018-01-01

Information of lens aberration of lithographic tools is important as it directly affects the intensity distribution in the image plane. Zernike polynomials are commonly used for a mathematical description of lens aberrations. Due to the advantage of lower cost and easier implementation of tools, image based measurement techniques have been widely used. Lithographic tools are typically partially coherent systems that can be described by a bilinear model, which entails time consuming calculations and does not lend a simple and intuitive relationship between lens aberrations and the resulted images. Previous methods for retrieving lens aberrations in such partially coherent systems involve through-focus image measurements and time-consuming iterative algorithms. In this work, we propose a method for aberration measurement in lithographic tools, which only requires measuring two images of intensity distribution. Two linear formulations are derived in matrix forms that directly relate the measured images to the unknown Zernike coefficients. Consequently, an efficient non-iterative solution is obtained.

Cell survival and radiation induced chromosome aberrations. Pt. 2

International Nuclear Information System (INIS)

Bauchinger, M.; Schmid, E.; Braselmann, H.

1986-01-01

Human peripheral lymphocytes were irradiated in whole blood with 0.5-4.0 Gy of 220 kVp X-rays and the frequency of chromosome aberrations was determined in 1st or 2nd division metaphases discriminated by fluorescence plus giemsa staining. Using the empirical distributions of aberrations among cells, cell survival and transmission of aberrations were investigated. Considering both daughter cells, we found that 20% of fragments and 55% of dicentrics or ring chromosomes are lost during the 1st cell division; i.e. cell survival rate from 1st to 2nd generation is mainly influenced by anaphase bridging of these two-hit aberrations. Cell survival to 2nd mitosis was calculated considering this situation and compared with the survival derived from the fraction of M1 cells without unstable aberrations. The resulting shouldered survival curves showed significantly different slopes, indicating that cell reproductive death is overestimated in the latter approach. (orig.)

Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

KAUST Repository

Sun, Tiancheng; Peng, Yifan; Heidrich, Wolfgang

2017-01-01

Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

KAUST Repository

Sun, Tiancheng

2017-12-25

Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

Higher-Order Wavefront Aberrations for Populations of Young Emmetropes and Myopes

Directory of Open Access Journals (Sweden)

Jinhua Bao

2009-01-01

Conclusions: Human eyes have systematical higher order aberrations in population, and factors that cause bilateral symmetry of wavefront aberrations between the right and left eyes made important contribution to the systematical aberrations.

Analysis of the 'dilemma effect' in fifth-order deflection aberration

International Nuclear Information System (INIS)

Zhang Xiaobing; Yin Hanchun; Lei Wei; Xue Kunxing; Tong Linsu

1999-01-01

In this paper, the coma of the fifth-order aberration at a large deflection angle has been analyzed by using multipole field theory. The dilemma effect exists in the comas of fifth-order aberration. The dilemma effect, whose value D r is constant and independent of the 10-pole field, is the linear combination of coma aberrations. The coma of the fifth-order aberration is corrected by adjusting the 10-pole field distribution when D r is zero or small. The factors that influence the dilemma effect have been calculated and analyzed

Chromatic aberrations of two-electrode transaxial mirrors

International Nuclear Information System (INIS)

Bejzina, L.G.; Karetskaya, S.P.

1991-01-01

Second order chromatic aberrations of electrostatic two-electrode transaxial mirrors in case the beam axial trajectory of charged particles is curvilinear are considered. Interrelations between coefficients of linear and angular chromatic aberrations are determined. Values of these coefficients for concave and convex transaxial mirrors with plane electrodes in dependence on potential ratio on electrodes by different onnular clearance radii are presented

Subjective face recognition difficulties, aberrant sensibility, sleeping disturbances and aberrant eating habits in families with Asperger syndrome

Directory of Open Access Journals (Sweden)

Källman Tiia

2005-04-01

Full Text Available Abstract Background The present study was undertaken in order to determine whether a set of clinical features, which are not included in the DSM-IV or ICD-10 for Asperger Syndrome (AS, are associated with AS in particular or whether they are merely a familial trait that is not related to the diagnosis. Methods Ten large families, a total of 138 persons, of whom 58 individuals fulfilled the diagnostic criteria for AS and another 56 did not to fulfill these criteria, were studied using a structured interview focusing on the possible presence of face recognition difficulties, aberrant sensibility and eating habits and sleeping disturbances. Results The prevalence for face recognition difficulties was 46.6% in individuals with AS compared with 10.7% in the control group. The corresponding figures for subjectively reported presence of aberrant sensibilities were 91.4% and 46.6%, for sleeping disturbances 48.3% and 23.2% and for aberrant eating habits 60.3% and 14.3%, respectively. Conclusion An aberrant processing of sensory information appears to be a common feature in AS. The impact of these and other clinical features that are not incorporated in the ICD-10 and DSM-IV on our understanding of AS may hitherto have been underestimated. These associated clinical traits may well be reflected by the behavioural characteristics of these individuals.

Brown's TRANSPORT up to third order aberration by artificial intelligence

International Nuclear Information System (INIS)

Xia Jiawen; Xie Xi; Qiao Qingwen

1991-01-01

Brown's TRANSPORT is a first and second order matrix multiplication computer program intended for the design of accelerator beam transport systems, neglecting the third order aberration. Recently a new method was developed to derive analytically any order aberration coefficients of general charged particle optic system, applicable to any practical systems, such as accelerators, electron microscopes, lithographs, etc., including those unknown systems yet to be invented. An artificial intelligence program in Turbo Prolog was implemented on IBM-PC 286 or 386 machine to generate automatically the analytical expression of any order aberration coefficients of general charged particle optic system. Based on this new method and technique, Brown's TRANSPORT is extended beyond the second order aberration effects by artificial intelligence, outputing automatically all the analytical expressions up to the third order aberration coefficients

Brown's transport up to third order aberration by artificial intelligence

International Nuclear Information System (INIS)

Xia Jiawen; Xie Xi; Qiao Qingwen

1992-01-01

Brown's TRANSPORT is a first and second order matrix multiplication computer program intended for the design of accelerator beam transport systems, neglecting the third order aberration. Recently a new method was developed to derive analytically any order aberration coefficients of general charged particle optic system, applicable to any practical systems, such as accelerators, electron microscopes, lithographs, including those unknown systems yet to be invented. An artificial intelligence program in Turbo Prolog was implemented on IBM-PC 286 or 386 machine to generate automatically the analytical expression of any order aberration coefficients of general charged particle optic system. Based on this new method and technique, Brown's TRANSPORT is extended beyond the second order aberration effect by artificial intelligence, outputting automatically all the analytical expressions up to the third order aberration coefficients

Chromosomal aberrations in subjects exposed to ionizing radiation

International Nuclear Information System (INIS)

Jovicic, D.; Milacic, S.; Kovacevic, R.; Tanaskovic, I.

2006-01-01

Occupational exposure is particularly delicate because of chronic exposure to low doses of ionizing radiation and its cumulative effect, where it is important to consider the biological response of body to given conditions of exposure. The objective of this study was the observation of the recovery of the DNA damages in subjects working in the radiation area in two different intervals.Group I, consisting of 30 subjects, was exposed to ionizing radiation and unstable chromosomal aberrations were identified. Group II included the same, re-examined subjects (30) 9 months later. It was verified that 5 (16.67%) subjects still had unstable chromosomal aberrations, although they had been excluded from radiation area Controls groups (C) consisted of 64 subjects that were not exposed to mutagenic agents.The comparison of the control group with the two studied groups revealed the reduction of the unstable aberrations (p<0.05). The total effective doses, which increased with the years spent in radiation area, reflected the yield of chromosomal aberrations. The presence of chromosomal aberrations in some subjects, after the exclusion from the ionising radiation exposure, suggests that the time needed for the recovery of the DNA damages is different, which indicates the individual differences in radiosensitivity as well as different of the reparatory cellular response. (author)

Spectral estimation for characterization of acoustic aberration.

Science.gov (United States)

Varslot, Trond; Angelsen, Bjørn; Waag, Robert C

2004-07-01

Spectral estimation based on acoustic backscatter from a motionless stochastic medium is described for characterization of aberration in ultrasonic imaging. The underlying assumptions for the estimation are: The correlation length of the medium is short compared to the length of the transmitted acoustic pulse, an isoplanatic region of sufficient size exists around the focal point, and the backscatter can be modeled as an ergodic stochastic process. The motivation for this work is ultrasonic imaging with aberration correction. Measurements were performed using a two-dimensional array system with 80 x 80 transducer elements and an element pitch of 0.6 mm. The f number for the measurements was 1.2 and the center frequency was 3.0 MHz with a 53% bandwidth. Relative phase of aberration was extracted from estimated cross spectra using a robust least-mean-square-error method based on an orthogonal expansion of the phase differences of neighboring wave forms as a function of frequency. Estimates of cross-spectrum phase from measurements of random scattering through a tissue-mimicking aberrator have confidence bands approximately +/- 5 degrees wide. Both phase and magnitude are in good agreement with a reference characterization obtained from a point scatterer.

Biodosimetry for medical diagnostic X-ray workers using stable chromosome aberration

International Nuclear Information System (INIS)

Wang Zhiquan; Liu Xuping; Li Jin

1996-01-01

The stable chromosome aberrations of medical diagnostic X-ray workers were analyzed using G-banding and their accumulative doses were evaluated. The results showed that the frequencies of reciprocal translocation, stable aberration and total aberration among the 4417 metaphase spread from 44 cases of medical diagnostic X-ray workers were distinctly higher than control values (P<0.05∼0.005). The stable aberration predominated strikingly in total aberration and reciprocal translocation was 57% in the stable aberrations. The medical diagnostic X-ray workers were divided into 3 groups according to calendar year of entry. The data showed that the frequencies of total aberration, stable aberration and reciprocal translocation increased with working years, especially in two groups who started working before 1970, there are statistically significant differences between the calendar year of entry before 1960 and 1960∼1969 in X-ray workers and control group. According to the equation recommended by Straume, linear coefficient (α) in linear quadratic model recommended by Schmid and the transformation coefficient by Lucas, the accumulative doses calculated are 0.58, 0.37 and 0.07 Gy for calendar year of entry before 1960, 1960∼1969 and after 1970 in X-ray workers, respectively

Higher order monochromatic aberrations of the human infant eye

OpenAIRE

Wang, Jingyun; Candy, T. Rowan

2005-01-01

The monochromatic optical aberrations of the eye degrade retinal image quality. Any significant aberrations during postnatal development could contribute to infants’ immature visual performance and provide signals for the control of eye growth. Aberrations of human infant eyes from 5 to 7 weeks old were compared with those of adult subjects using a model of an adultlike infant eye that accounted for differences in both eye and pupil size. Data were collected using the COAS Shack-Hartmann wave...

Chromosomal aberrations in children exposed to diagnostic x-rays

International Nuclear Information System (INIS)

Nordenson, I.; Beckman, G.; Beckman, L.; Lemperg, R.

1980-01-01

Among children who have received high x-ray doses congenital dislocation of the hip joint is the predominating diagnosis. In a series of 9 children who had received high x-ray doses (8 with luxation of the hip joint and one with achondroplasia) a significant increase of chromosomal aberrations was found. The increase concerned mainly chromosome type aberrations. The shorter the time since the last x-ray investigation the higher was the frequency of chromosome type aberrations. (author)

[Patterns of morphological variability in reintroduced populations with two beaver subspecies Castor fiber orientoeuropaeus and Castor fiber belorussicus (Castoridae, Rodentia) as an example].

Science.gov (United States)

Korablev, N P; Korablev, P N

2012-01-01

Taking as an example two beaver subspecies (Castor fiber orientoeuropaeus and Castor fiber belorussicus) with documented history of population formation, the patterns of morphological variability in translocated groups of mammals are studied. The variability of quantitative and qualitative traits in the formed populations is not characterized by a single direction. The main trend consists in increasing of adaptive norms diversity as related to body size. There observed a slight increase in the level of fluctuating asymmetry, reduction in polymorphism of nonmetric traits, and increase in fraction of rare aberrations. All these may be caused by inbreeding taking place during the period of prapopulations formation. The results of the study allow for considering the intraspecific differentiation as a consequence of adaptive variability (adaptatiogenesis) or subspecies hybridization. As for stochastic processes (genetic drift, founder effect), they seem to not influence the morphological variability significantly. The differences between discrete and dimensional traits are indicative of population groups' peculiarity.

Disrupted Structural Brain Network in AD and aMCI: A Finding of Long Fiber Degeneration.

Science.gov (United States)

Fang, Rong; Yan, Xiao-Xiao; Wu, Zhi-Yuan; Sun, Yu; Yin, Qi-Hua; Wang, Ying; Tang, Hui-Dong; Sun, Jun-Feng; Miao, Fei; Chen, Sheng-Di

2015-01-01

Although recent evidence has emerged that Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) patients show both regional brain abnormalities and topological degeneration in brain networks, our understanding of the effects of white matter fiber aberrations on brain network topology in AD and aMCI is still rudimentary. In this study, we investigated the regional volumetric aberrations and the global topological abnormalities in AD and aMCI patients. The results showed a widely distributed atrophy in both gray and white matters in the AD and aMCI groups. In particular, AD patients had weaker connectivity with long fiber length than aMCI and normal control (NC) groups, as assessed by fractional anisotropy (FA). Furthermore, the brain networks of all three groups exhibited prominent economical small-world properties. Interestingly, the topological characteristics estimated from binary brain networks showed no significant group effect, indicating a tendency of preserving an optimal topological architecture in AD and aMCI during degeneration. However, significantly longer characteristic path length was observed in the FA weighted brain networks of AD and aMCI patients, suggesting dysfunctional global integration. Moreover, the abnormality of the characteristic path length was negatively correlated with the clinical ratings of cognitive impairment. Thus, the results therefore suggested that the topological alterations in weighted brain networks of AD are induced by the loss of connectivity with long fiber lengths. Our findings provide new insights into the alterations of the brain network in AD and may indicate the predictive value of the network metrics as biomarkers of disease development.

In vivo longitudinal chromatic aberration of pseudophakic eyes.

Science.gov (United States)

Siedlecki, Damian; Jóźwik, Agnieszka; Zając, Marek; Hill-Bator, Aneta; Turno-Kręcicka, Anna

2014-02-01

To present the results of longitudinal chromatic aberration measurements on two groups of pseudophakic eyes in comparison to healthy eyes. The longitudinal chromatic aberration of the eye, defined as chromatic difference of refraction with disabled accommodation, was measured with the use of a visual refractometer with a custom-designed target illuminator consisting of a narrow-band RGB diode (blue λb = 470 ± 15 nm; green λg = 525 ± 18 nm; red λr = 660 ± 10 nm). The measurements were performed on nine eyes implanted with AcrySof IQ SN60WF, 14 eyes implanted with AcrySof SA60AT, and 10 phakic eyes under cycloplegia. The mean values of the longitudinal chromatic aberration between 470 and 660 nm for the control group was 1.12 ± 0.14 D. For SA60AT group, it was 1.45 ± 0.42 D whereas for SN60WF it was 1.17 ± 0.52 D. The statistical test showed significant difference between SA60AT and the control group (p chromatic aberration in vivo can be easily and reliably estimated with an adapted visual refractometer. The two groups of pseudophakic eyes measured in this study showed different values of chromatic aberration. Its magnitude for SA60AT group was significantly larger than for the control group whereas for SN60WF the difference was not significant. The optical material used for intraocular lens design may have significant influence on the magnitude of the chromatic aberration of the pseudophakic eye, and therefore on its optical and visual performance in polychromatic light.

Cellular origin of prognostic chromosomal aberrations in AML patients

DEFF Research Database (Denmark)

Mora-Jensen, H.; Jendholm, J.; Rapin, N.

2015-01-01

chromosomal structural rearrangements and single nucleotide variants (SNVs). Conventional AML diagnostics and recent seminal next-generation sequencing (NGS) studies have identified more than 200 recurrent genetic aberrations presenting in various combinations in individual patients. Significantly, many...... of these aberrations occur in normal hematopoietic stem and progenitor cells (HSCs/HPCs) before definitive leukemic transformation through additional acquisition of a few (that is, mostly 1 or 2) leukemia-promoting driver aberrations. NGS studies on sorted bone marrow (BM) populations of AML patients with a normal...

Aberration Correction in the Brewer Spectrophotometer

International Nuclear Information System (INIS)

Johnston, J.E.; Kerr, J.B.; McElroy, C.T.; Wardle, D.I.

2000-01-01

The optical design of the Brewer Spectrophotometer has been optimised for measurements in the 300-320 nm wavelength range. An aberration resolution limit that is much less than the 0.6 nm FWHM (full width at half maximum) is achieved by using an Ebert-Fastie spectrometer design, modified by the inclusion tilted lens that optimises performance at 310 nm. The small contribution of the remaining aberration to the measured instrument function is critical to radiometric measurement quality. Ramifications of this design to the development of instrumentation with enhanced scanning abilities are discussed. (author)

Dimensions of driving anger and their relationships with aberrant driving.

Science.gov (United States)

Zhang, Tingru; Chan, Alan H S; Zhang, Wei

2015-08-01

The purpose of this study was to investigate the relationship between driving anger and aberrant driving behaviours. An internet-based questionnaire survey was administered to a sample of Chinese drivers, with driving anger measured by a 14-item short Driving Anger Scale (DAS) and the aberrant driving behaviours measured by a 23-item Driver Behaviour Questionnaire (DBQ). The results of Confirmatory Factor Analysis demonstrated that the three-factor model (hostile gesture, arrival-blocking and safety-blocking) of the DAS fitted the driving anger data well. The Exploratory Factor Analysis on DBQ data differentiated four types of aberrant driving, viz. emotional violation, error, deliberate violation and maintaining progress violation. For the anger-aberration relation, it was found that only "arrival-blocking" anger was a significant positive predictor for all four types of aberrant driving behaviours. The "safety-blocking" anger revealed a negative impact on deliberate violations, a finding different from previously established positive anger-aberration relation. These results suggest that drivers with different patterns of driving anger would show different behavioural tendencies and as a result intervention strategies may be differentially effective for drivers of different profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ocular wavefront aberration and refractive error in pre-school children

Science.gov (United States)

Thapa, Damber; Fleck, Andre; Lakshminarayanan, Vasudevan; Bobier, William R.

2011-11-01

Hartmann-Shack images taken from an archived collection of SureSight refractive measurements of pre-school children in Oxford County, Ontario, Canada were retrieved and re-analyzed. Higher-order aberrations were calculated over the age range of 3 to 6 years. These higher-order aberrations were compared with respect to magnitudes of ametropia. Subjects were classified as emmetropic (range -0.5 to + 0.5D), low hyperopic (+ 0.5 to +2D) and high hyperopic (+2D or more) based upon the resulting spherical equivalent. Higher-order aberrations were found to increase with higher levels of hyperopia (p < 0.01). The strongest effect was for children showing more than +2.00D of hyperopia. The correlation coefficients were small in all of the higher-order aberrations; however, they were significant (p < 0.01). These analyses indicate a weak association between refractive error and higher-order aberrations in pre-school children.

Prospects for electron beam aberration correction using sculpted phase masks

Energy Technology Data Exchange (ETDEWEB)

Shiloh, Roy, E-mail: royshilo@post.tau.ac.il; Remez, Roei; Arie, Ady

2016-04-15

Technological advances in fabrication methods allowed the microscopy community to take incremental steps towards perfecting the electron microscope, and magnetic lens design in particular. Still, state of the art aberration-corrected microscopes are yet 20–30 times shy of the theoretical electron diffraction limit. Moreover, these microscopes consume significant physical space and are very expensive. Here, we show how a thin, sculpted membrane is used as a phase-mask to induce specific aberrations into an electron beam probe in a standard high resolution TEM. In particular, we experimentally demonstrate beam splitting, two-fold astigmatism, three-fold astigmatism, and spherical aberration. - Highlights: • Thin membranes can be used as aberration correctors in electron columns. • We demonstrate tilt, twofold-, threefold-astigmatism, and spherical aberrations. • Experimental and physical-optics simulation results are in good agreement. • Advantages in cost, size, nonmagnetism, and nearly-arbitrary correction.

Comparison of wavefront aberrations under cycloplegic, scotopic and photopic conditions using WaveScan

Directory of Open Access Journals (Sweden)

Rong Fan

2012-04-01

Full Text Available PURPOSE: To evaluate the differences of wavefront aberrations under cycloplegic, scotopic and photopic conditions. METHODS: A total of 174 eyes of 105 patients were measured using the wavefront sensor (WaveScan® 3.62 under different pupil conditions: cycloplegic 8.58 ± 0.54 mm (6.4 mm - 9.5 mm, scotopic 7.53 ± 0.69 mm (5.7 mm - 9.1 mm and photopic 6.08 ± 1.14 mm (4.1 mm - 8.8 mm. The pupil diameter, standard Zernike coefficients, root mean square of higher-order aberrations and dominant aberrations were compared between cycloplegic and scotopic conditions, and between scotopic and photopic conditions. RESULTS: The pupil diameter was 7.53 ± 0.69 mm under the scotopic condition, which reached the requirement of about 6.5 mm optical zone design in the wavefront-guided surgery and prevented measurement error due to the pupil centroid shift caused by mydriatics. Pharmacological pupil dilation induced increase of standard Zernike coefficients Z3-3, Z4(0 and Z5-5. The higher-order aberrations, third-order aberration, fourth-order aberration, fifth-order aberration, sixth-order aberration, and spherical aberration increased statistically significantly, compared to the scotopic condition (P<0.010. When the scotopic condition shifted to the photopic condition, the standard Zernike coefficients Z4(0, Z4², Z6-4, Z6-2, Z6² decreased and all the higher-order aberrations decreased statistically significantly (P<0.010, demonstrating that accommodative miosis can significantly improve vision under the photopic condition. Under the three conditions, the vertical coma aberration appears the most frequently within the dominant aberrations without significant effect by pupil size variance, and the proportion of spherical aberrations decreased with the decrease of the pupil size. CONCLUSIONS: The wavefront aberrations are significantly different under cycloplegic, scotopic and photopic conditions. Using the wavefront sensor (VISX WaveScan to measure scotopic

Aberrant salience, self-concept clarity, and interview-rated psychotic-like experiences.

Science.gov (United States)

Cicero, David C; Docherty, Anna R; Becker, Theresa M; Martin, Elizabeth A; Kerns, John G

2015-02-01

Many social-cognitive models of psychotic-like symptoms posit a role for self-concept and aberrant salience. Previous work has shown that the interaction between aberrant salience and self-concept clarity is associated with self-reported psychotic-like experiences. In the current research with two structured interviews, the interaction between aberrant salience and self-concept clarity was found to be associated with interview-rated psychotic-like experiences. The interaction was associated with psychotic-like experiences composite scores, delusional ideation, grandiosity, and perceptual anomalies. In all cases, self-concept clarity was negatively associated with psychotic-like experiences at high levels of aberrant salience, but unassociated with psychotic-like experiences at low levels of aberrant salience. The interaction was specific to positive psychotic-like experiences and not present for negative or disorganized ratings. The interaction was not mediated by self-esteem levels. These results provide further evidence that aberrant salience and self-concept clarity play an important role in the generation of psychotic-like experiences.

The primary vestibular projection to the cerebellar cortex in the pigeon (Columba livia)

Energy Technology Data Exchange (ETDEWEB)

Schwarz, I.E.; Schwarz, D.W.

1983-06-01

The cerebellar cortex of the pigeon receiving direct vestibular afferents was delineated by anterograde transport of (/sup 3/H)-amino acids injected into the vestibular nerve. Labelled mossy fiber rosettes in the granular layer were concentrated in lobule X (nodulus) and to a lesser extent, in the ventral portion of lobule IXd (uvula and paraflocculus). A few solitary labelled rosettes were also found in more dorsal portions of lobule IX, as well as in the anterior lobe between lobule II and IV. The lingula remained unlabelled. Discrete injections of (/sup 3/H)-leucine into the cristae of each of the three semicircular canals or the utricular macula yielded a similar distribution of fewer labelled rosettes. A few primary mossy fiber terminals labelled after cochlear injections are attributed to afferents from the lagenar macula. Since effective diffusion of label from the injection site was excluded by controls, it is concluded that projection of individual canal and macula nerves to the vestibulocerebellar cortex is not topographically separated. It is proposed that this extensive convergence of various afferents is required by the cerebellum to compute precise and directionally specific control signals during head rotation in all conceivable planes.

The primary vestibular projection to the cerebellar cortex in the pigeon (Columba livia)

International Nuclear Information System (INIS)

Schwarz, I.E.; Schwarz, D.W.

1983-01-01

The cerebellar cortex of the pigeon receiving direct vestibular afferents was delineated by anterograde transport of [ 3 H]-amino acids injected into the vestibular nerve. Labelled mossy fiber rosettes in the granular layer were concentrated in lobule X (nodulus) and to a lesser extent, in the ventral portion of lobule IXd (uvula and paraflocculus). A few solitary labelled rosettes were also found in more dorsal portions of lobule IX, as well as in the anterior lobe between lobule II and IV. The lingula remained unlabelled. Discrete injections of [ 3 H]-leucine into the cristae of each of the three semicircular canals or the utricular macula yielded a similar distribution of fewer labelled rosettes. A few primary mossy fiber terminals labelled after cochlear injections are attributed to afferents from the lagenar macula. Since effective diffusion of label from the injection site was excluded by controls, it is concluded that projection of individual canal and macula nerves to the vestibulocerebellar cortex is not topographically separated. It is proposed that this extensive convergence of various afferents is required by the cerebellum to compute precise and directionally specific control signals during head rotation in all conceivable planes

Recurrent branchial sinus tract with aberrant extension.

Science.gov (United States)

Barret, J P

2004-01-01

Second branchial cysts are the commonest lesions among congenital lateral neck anomalies. Good knowledge of anatomy and embryology are necessary for proper treatment. Surgical treatment involves resection of all branchial remnants, which extend laterally in the neck, medial to the sternocleidomastoid muscle with cranial extension to the pharynx and ipsilateral tonsillar fosa. However, infections and previous surgery can distort anatomy, making the approach to branchial anomalies more difficult. We present a case of a 17-year-old patient who presented with a second branchial tract anomaly with an aberrant extension to the midline and part of the contralateral neck. Previous surgical interventions and chronic infections may have been the primary cause for this aberrant tract. All head and neck surgeons should bear in mind that aberrant presentations may exist when reoperating on chronic branchial cysts fistulas.

Study of radiation-induced chromosomal aberrations

International Nuclear Information System (INIS)

Wolfring, E.

2004-06-01

A method for determining chromosomal aberrations was established for the purpose of examining the relative biological effectiveness (RBE) of photon radiation with respect to mammary epithelium cells. Cells were exposed to 25 kV X-radiation and to 200 kV X-radiation for comparison and the resulting concentrations of chromosomal aberrations were compared. The RBE M value for radiation-induced fragmentation was found to be 4.2 ± 2.4, while the RBE M value for radiation-induced generation of dicentric chromosomes was found to be 0.5 ± 0.5. In addition to the evaluation of chromosomal aberrations the number of cell cycles undergone by the cells was monitored by means of BrDU staining. As expected, the proportion of cells which underwent more than one cell cycle following exposure to 5 Gy was very low in both cases, amounting to 1.9% (25 kV) and 3.2 (200 kV). Non-radiated cells yielded control values of 26.0% and 12.6%, suggesting variations in external conditions from day to day

Sextupole system for the correction of spherical aberration

Science.gov (United States)

Crewe, A.V.; Kopf, D.A.

In an electron beam device in which an electron beam is developed and then focused by a lens to a particular spot, there is provided a means for eliminating spherical aberration. A sextupole electromagnetic lens is positioned between two focusing lenses. The interaction of the sextupole with the beam compensates for spherical aberration. (GHT)

Brillouin micro-spectroscopy through aberrations via sensorless adaptive optics

Science.gov (United States)

Edrei, Eitan; Scarcelli, Giuliano

2018-04-01

Brillouin spectroscopy is a powerful optical technique for non-contact viscoelastic characterizations which has recently found applications in three-dimensional mapping of biological samples. Brillouin spectroscopy performances are rapidly degraded by optical aberrations and have therefore been limited to homogenous transparent samples. In this work, we developed an adaptive optics (AO) configuration designed for Brillouin scattering spectroscopy to engineer the incident wavefront and correct for aberrations. Our configuration does not require direct wavefront sensing and the injection of a "guide-star"; hence, it can be implemented without the need for sample pre-treatment. We used our AO-Brillouin spectrometer in aberrated phantoms and biological samples and obtained improved precision and resolution of Brillouin spectral analysis; we demonstrated 2.5-fold enhancement in Brillouin signal strength and 1.4-fold improvement in axial resolution because of the correction of optical aberrations.

Theoretical estimates of spherical and chromatic aberration in photoemission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Fitzgerald, J.P.S., E-mail: fit@pdx.edu; Word, R.C.; Könenkamp, R.

2016-01-15

We present theoretical estimates of the mean coefficients of spherical and chromatic aberration for low energy photoemission electron microscopy (PEEM). Using simple analytic models, we find that the aberration coefficients depend primarily on the difference between the photon energy and the photoemission threshold, as expected. However, the shape of the photoelectron spectral distribution impacts the coefficients by up to 30%. These estimates should allow more precise correction of aberration in PEEM in experimental situations where the aberration coefficients and precise electron energy distribution cannot be readily measured. - Highlights: • Spherical and chromatic aberration coefficients of the accelerating field in PEEM. • Compact, analytic expressions for coefficients depending on two emission parameters. • Effect of an aperture stop on the distribution is also considered.

A model of distributed phase aberration for deblurring phase estimated from scattering.

Science.gov (United States)

Tillett, Jason C; Astheimer, Jeffrey P; Waag, Robert C

2010-01-01

Correction of aberration in ultrasound imaging uses the response of a point reflector or its equivalent to characterize the aberration. Because a point reflector is usually unavailable, its equivalent is obtained using statistical methods, such as processing reflections from multiple focal regions in a random medium. However, the validity of methods that use reflections from multiple points is limited to isoplanatic patches for which the aberration is essentially the same. In this study, aberration is modeled by an offset phase screen to relax the isoplanatic restriction. Methods are developed to determine the depth and phase of the screen and to use the model for compensation of aberration as the beam is steered. Use of the model to enhance the performance of the noted statistical estimation procedure is also described. Experimental results obtained with tissue-mimicking phantoms that implement different models and produce different amounts of aberration are presented to show the efficacy of these methods. The improvement in b-scan resolution realized with the model is illustrated. The results show that the isoplanatic patch assumption for estimation of aberration can be relaxed and that propagation-path characteristics and aberration estimation are closely related.

Mutations and chromosomal aberrations

International Nuclear Information System (INIS)

Kihlman, B.A.

1977-01-01

The genetic changes of mutations and chromosomal aberrations are discussed. The consequences of both depend not only on the type of genetic change produced but also on the type of cell that is affected and on the development stage of the organism. (C.F.)

Effects of residual aberrations explored on single-walled carbon nanotubes

International Nuclear Information System (INIS)

Biskupek, Johannes; Hartel, Peter; Haider, Maximilian; Kaiser, Ute

2012-01-01

The effects of geometric residual aberrations such as coma B 2 and two-fold astigmatism A 1 on the contrast in aberration corrected high resolution transmission electron microscopy (HRTEM) images are investigated on single-walled carbon nanotubes (SWNT). The individual aberrations are adjusted and set up manually using an imaging C S -corrector. We demonstrate how coma B 2 can be recognized by an experienced user directly in the image and how it blurs the contrast. Even with uncorrected (resolution limiting) spherical aberration C S the coma B 2 has to be considered and must be minimized. Limits for a tolerable coma are given. The experiments are confirmed by image simulations. -- Highlights: ► Individual effects of residual aberrations such as B 2 , A 1 , and C S are demonstrated. ► Experimental HRTEM and simulated images of carbon nanotubes are compared. ► A detection limit of 50 nm B 2 in a single HRTEM image is determined.

Correlation between Post-LASIK Starburst Symptom and Ocular Wavefront Aberrations

Science.gov (United States)

Liu, Yong-Ji; Mu, Guo-Guang; Wang, Zhao-Qi; Wang-Yan

2006-06-01

Monochromatic aberrations in post laser in-situ keratomileusis (LASIK) eyes are measured. The data are categorized into reference group and starburst group according to the visual symptoms. Statistic analysis has been made to find the correlation between the ocular wavefront aberrations and the starburst symptom. The rms aberrations of the 3rd and 4th orders for the starburst group are significantly larger than those for the reference group. The starburst symptom shows a strong correlation with vertical coma, total coma, spherical aberrations. For 3-mm pupil size and 5.8-mm pupil size, the modulation transfer function (MTF) of the starburst group are lower than those of the reference group, but their visual acuities are close. MTF and PSF analyses are made for two groups, and the results are consistent with the statistical analysis, which means the difference between the two groups is mainly due to the third- and fourth-order Zernike aberrations.

Split-plot fractional designs: Is minimum aberration enough?

DEFF Research Database (Denmark)

Kulahci, Murat; Ramirez, Jose; Tobias, Randy

2006-01-01

Split-plot experiments are commonly used in industry for product and process improvement. Recent articles on designing split-plot experiments concentrate on minimum aberration as the design criterion. Minimum aberration has been criticized as a design criterion for completely randomized fractional...... factorial design and alternative criteria, such as the maximum number of clear two-factor interactions, are suggested (Wu and Hamada (2000)). The need for alternatives to minimum aberration is even more acute for split-plot designs. In a standard split-plot design, there are several types of two...... for completely randomized designs. Consequently, we provide a modified version of the maximum number of clear two-factor interactions design criterion to be used for split-plot designs....

Biological dosimetry: chromosomal aberration analysis for dose assessment

International Nuclear Information System (INIS)

1986-01-01

In view of the growing importance of chromosomal aberration analysis as a biological dosimeter, the present report provides a concise summary of the scientific background of the subject and a comprehensive source of information at the technical level. After a review of the basic principles of radiation dosimetry and radiation biology basic information on the biology of lymphocytes, the structure of chromosomes and the classification of chromosomal aberrations are presented. This is followed by a presentation of techniques for collecting blood, storing, transporting, culturing, making chromosomal preparations and scaring of aberrations. The physical and statistical parameters involved in dose assessment are discussed and examples of actual dose assessments taken from the scientific literature are given

Differential algebraic method for arbitrary order curvilinear-axis combined geometric-chromatic aberration analysis

International Nuclear Information System (INIS)

Cheng Min; Tang Tiantong; Lu Yilong; Yao Zhenhua

2003-01-01

The principle of differential algebra is applied to analyse and calculate arbitrary order curvilinear-axis combined geometric-chromatic aberrations of electron optical systems. Expressions of differential algebraic form of high order combined aberrations are obtained and arbitrary order combined aberrations can be calculated numerically. As an example, a typical wide electron beam focusing system with curved optical axes named magnetic immersion lens has been studied. All the second-order and third-order combined geometric-chromatic aberrations of the lens have been calculated, and the patterns of the corresponding geometric aberrations and combined aberrations have been given as well

Population spherical aberration: associations with ametropia, age, corneal curvature, and image quality

Directory of Open Access Journals (Sweden)

Kingston AC

2013-05-01

Full Text Available Amanda C Kingston,1,2 Ian G Cox11Bausch + Lomb, Rochester, NY, USA; 2Department of Biomedical Engineering, University of Rochester, Rochester, NY, USAPurpose: The aim of this analysis was to determine the total ocular wavefront aberration values of a large phakic population of physiologically normal, ametropic eyes, gathered under the same clinical protocol using the same diagnostic wavefront sensor.Materials and methods: Studies were conducted at multiple sites in Asia, North America, Europe, and Australia. A Bausch + Lomb Zywave II Wavefront Aberrometer (Rochester, NY, USA was used to measure the lower and higher order aberrations of each eye. Data analysis was conducted using linear regression analysis to determine the relationship between total spherical aberration, ametropia, age, corneal curvature, and image quality.Results: Linear regression analysis showed no correlation (r = 0.0207, P = 0.4874 between degree of ametropia and the amount of spherical aberration. There was also no correlation when the population was stratified into myopic and hyperopic refractive groups (rm = 0.0529, Pm = 0.0804 and rh = 0.1572, Ph = 0.2754. There was a statistically significant and weak positive correlation (r = 0.1962, P < 0.001 between age and the amount of spherical aberration measured in the eye; spherical aberration became more positive with increasing age. Also, there was a statistically significant and moderately positive correlation (r = 0.3611, P < 0.001 with steepness of corneal curvature; spherical aberration became more positive with increasing power of the anterior corneal surface. Assessment of image quality using optical design software (Zemax™, Bellevue, WA, USA showed that there was an overall benefit in correcting the average spherical aberration of this population.Conclusion: Analysis of this dataset provides insights into the inherent spherical aberration of a typical phakic, pre-presbyopic, population and provides the ability to

Aberration analysis calculations for synchrotron radiation beamline design

International Nuclear Information System (INIS)

McKinney, W.R.; Howells, M.; Padmore, H.A.

1997-09-01

The application of ray deviation calculations based on aberration coefficients for a single optical surface for the design of beamline optical systems is reviewed. A systematic development is presented which allows insight into which aberration may be causing the rays to deviate from perfect focus. A new development allowing analytical calculation of line shape is presented

Fifth-order aberrations in magnetic quadrupole-octupole systems

International Nuclear Information System (INIS)

Ling, K.M.

1990-01-01

Explicit integral expressions are given for the fifth-order geometrical aberration coefficients in rectilinear magnetic quadrupole-octupole systems used for the transport of nonrelativistic charged particle beams. The numerical values of the fifth-order geometrical aberration coefficients for a rare earth cobalt (REC) quadrupole doublet are given as an example. 26 refs., 5 figs., 4 tabs

Lethality of radiation-induced chromosome aberrations in human tumour cell lines with different radiosensitivities.

Science.gov (United States)

Coco-Martin, J M; Ottenheim, C P; Bartelink, H; Begg, A C

1996-03-01

In order to find an explanation for the eventual disappearance of all chromosome aberrations in two radiosensitive human tumour cell lines, the type and stability of different aberration types was investigated in more detail. To classify the aberrations into unstable and stable types, three-colour fluorescence in situ hybridization was performed, including a whole-chromosome probe, a pancentromere probe, and a stain for total DNA. This technique enables the appropriate classification of the aberrations principally by the presence (stable) or not (unstable) of a single centromere per chromosome. Unstable-type aberrations were found to disappear within 7 days (several divisions) in the two radiosensitive and the two radioresistant tumour lines investigated. Stable-type aberrations were found to remain at an approximately constant level over the duration of the experiment (14 days; 8-10 divisions) in the two radioresistant lines. In contrast, the majority of these stable-type aberrations had disappeared by 14 days in the two radiosensitive lines. The previous findings of disappearance of total aberrations in radiosensitive cells was therefore not due to a reduced induction of stable-type aberrations, but the complete disappearance of cells with this aberration type. These results could not be explained by differences in apoptosis or G1 blocks. Two possible explanations for these unexpected findings involve non-random induction of unstable-type aberrations, or lethality of stable-type aberrations. The results suggest caution in the use of stable-type aberration numbers as a predictor for radiosensitivity.

Influence of coma aberration on aperture averaged scintillations in oceanic turbulence

Science.gov (United States)

Luo, Yujuan; Ji, Xiaoling; Yu, Hong

2018-01-01

The influence of coma aberration on aperture averaged scintillations in oceanic turbulence is studied in detail by using the numerical simulation method. In general, in weak oceanic turbulence, the aperture averaged scintillation can be effectively suppressed by means of the coma aberration, and the aperture averaged scintillation decreases as the coma aberration coefficient increases. However, in moderate and strong oceanic turbulence the influence of coma aberration on aperture averaged scintillations can be ignored. In addition, the aperture averaged scintillation dominated by salinity-induced turbulence is larger than that dominated by temperature-induced turbulence. In particular, it is shown that for coma-aberrated Gaussian beams, the behavior of aperture averaged scintillation index is quite different from the behavior of point scintillation index, and the aperture averaged scintillation index is more suitable for characterizing scintillations in practice.

The role of aberrant mitochondrial bioenergetics in diabetic neuropathy.

Science.gov (United States)

Chowdhury, Subir K Roy; Smith, Darrell R; Fernyhough, Paul

2013-03-01

Diabetic neuropathy is a neurological complication of diabetes that causes significant morbidity and, because of the obesity-driven rise in incidence of type 2 diabetes, is becoming a major international health problem. Mitochondrial phenotype is abnormal in sensory neurons in diabetes and may contribute to the etiology of diabetic neuropathy where a distal dying-back neurodegenerative process is a key component contributing to fiber loss. This review summarizes the major features of mitochondrial dysfunction in neurons and Schwann cells in human diabetic patients and in experimental animal models (primarily exhibiting type 1 diabetes). This article attempts to relate these findings to the development of critical neuropathological hallmarks of the disease. Recent work reveals that hyperglycemia in diabetes triggers nutrient excess in neurons that, in turn, mediates a phenotypic change in mitochondrial biology through alteration of the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling axis. This vital energy sensing metabolic pathway modulates mitochondrial function, biogenesis and regeneration. The bioenergetic phenotype of mitochondria in diabetic neurons is aberrant due to deleterious alterations in expression and activity of respiratory chain components as a direct consequence of abnormal AMPK/PGC-1α signaling. Utilization of innovative respirometry equipment to analyze mitochondrial function of cultured adult sensory neurons from diabetic rodents shows that the outcome for cellular bioenergetics is a reduced adaptability to fluctuations in ATP demand. The diabetes-induced maladaptive process is hypothesized to result in exhaustion of the ATP supply in the distal nerve compartment and induction of nerve fiber dissolution. The role of mitochondrial dysfunction in the etiology of diabetic neuropathy is compared with other types of neuropathy with a distal dying-back pathology such as Friedreich

Screening for aberrant behavior in the nuclear industry

International Nuclear Information System (INIS)

Borofsky, G.L.

1987-01-01

This paper attempts to promote a fuller understanding of how psychological assessment procedures can be used to reduce the threat from aberrant behavior in the nuclear industry. It begins with a discussion of the scientifically based methods that are used by psychologists in constructing, scoring, and interpreting these procedures. This discussion includes an emphasis on the concepts of validity and reliability and their central importance when one is choosing specific psychological screening tools. Criteria for selecting and using psychological assessment procedures when screening for aberrant behavior are also provided. Some commonly used assessment procedures that satisfy these criteria are discussed. A number a psychological assessment procedures specifically recommended for use in screening for aberrant behavior in the nuclear industry are described

Detecting Aberrant Response Patterns in the Rasch Model. Rapport 87-3.

Science.gov (United States)

Kogut, Jan

In this paper, the detection of response patterns aberrant from the Rasch model is considered. For this purpose, a new person fit index, recently developed by I. W. Molenaar (1987) and an iterative estimation procedure are used in a simulation study of Rasch model data mixed with aberrant data. Three kinds of aberrant response behavior are…

The organization of plasticity in the cerebellar cortex: from synapses to control.

Science.gov (United States)

D'Angelo, Egidio

2014-01-01

The cerebellum is thought to play a critical role in procedural learning, but the relationship between this function and the underlying cellular and synaptic mechanisms remains largely speculative. At present, at least nine forms of long-term synaptic and nonsynaptic plasticity (some of which are bidirectional) have been reported in the cerebellar cortex and deep cerebellar nuclei. These include long-term potentiation (LTP) and long-term depression at the mossy fiber-granule cell synapse, at the synapses formed by parallel fibers, climbing fibers, and molecular layer interneurons on Purkinje cells, and at the synapses formed by mossy fibers and Purkinje cells on deep cerebellar nuclear cells, as well as LTP of intrinsic excitability in granule cells, Purkinje cells, and deep cerebellar nuclear cells. It is suggested that the complex properties of cerebellar learning would emerge from the distribution of plasticity in the network and from its dynamic remodeling during the different phases of learning. Intrinsic and extrinsic factors may hold the key to explain how the different forms of plasticity cooperate to select specific transmission channels and to regulate the signal-to-noise ratio through the cerebellar cortex. These factors include regulation of neuronal excitation by local inhibitory networks, engagement of specific molecular mechanisms by spike bursts and theta-frequency oscillations, and gating by external neuromodulators. Therefore, a new and more complex view of cerebellar plasticity is emerging with respect to that predicted by the original "Motor Learning Theory," opening issues that will require experimental and computational testing. © 2014 Elsevier B.V. All rights reserved.

Intelligent Network Management and Functional Cerebellum Synthesis

Science.gov (United States)

Loebner, Egon E.

1989-01-01

Transdisciplinary modeling of the cerebellum across histology, physiology, and network engineering provides preliminary results at three organization levels: input/output links to central nervous system networks; links between the six neuron populations in the cerebellum; and computation among the neurons of the populations. Older models probably underestimated the importance and role of climbing fiber input which seems to supply write as well as read signals, not just to Purkinje but also to basket and stellate neurons. The well-known mossy fiber-granule cell-Golgi cell system should also respond to inputs originating from climbing fibers. Corticonuclear microcomplexing might be aided by stellate and basket computation and associate processing. Technological and scientific implications of the proposed cerebellum model are discussed.

Histopathologic characterization of the BTBR mouse model of autistic-like behavior reveals selective changes in neurodevelopmental proteins and adult hippocampal neurogenesis

Directory of Open Access Journals (Sweden)

Stephenson Diane T

2011-05-01

doublecortin, PSA-NCAM and NeuroD immunoreactive cells in the subgranular zone of the dentate gyrus, and a marked reduction in the number of 5-bromo-2'-deoxyuridine (BrdU positive progenitors. Furthermore, a significant and profound reduction in BDNF mRNA was seen in the BTBR dentate gyrus. No significant differences were seen in the expression of AchE, mossy fiber synapses or immunoreactivities of microtubule-associated protein MAP2, parvalbumin and glutamate decarboxylase GAD65 or GAD67 isoforms. Conclusions We documented modest and selective alterations in glia, neurons and synapses in BTBR forebrain, along with reduced neurogenesis in the adult hippocampus. Of all markers examined, the most distinctive changes were seen in the neurodevelopmental proteins NG2, PSA-NCAM, NeuroD and DCX. Our results are consistent with aberrant development of the nervous system in BTBR mice, and may reveal novel substrates to link callosal abnormalities and autistic behaviors. The changes that we observed in the BTBR mice suggest potential novel therapeutic strategies for intervention in autism spectrum disorders.

Effects of ocular aberrations on contrast detection in noise.

Science.gov (United States)

Liang, Bo; Liu, Rong; Dai, Yun; Zhou, Jiawei; Zhou, Yifeng; Zhang, Yudong

2012-08-06

We use adaptive optics (AO) techniques to manipulate the ocular aberrations and elucidate the effects of these ocular aberrations on contrast detection in a noisy background. The detectability of sine wave gratings at frequencies of 4, 8, and 16 circles per degree (cpd) was measured in a standard two-interval force-choice staircase procedure against backgrounds of various levels of white noise. The observer's ocular aberrations were either corrected with AO or left uncorrected. In low levels of external noise, contrast detection thresholds are always lowered by AO correction, whereas in high levels of external noise, they are generally elevated by AO correction. Higher levels of external noise are required to make this threshold elevation observable when signal spatial frequencies increase from 4 to 16 cpd. The linear-amplifier-model fit shows that mostly sampling efficiency and equivalent noise both decrease with AO correction. Our findings indicate that ocular aberrations could be beneficial for contrast detection in high-level noises. The implications of these findings are discussed.

Chromosome aberrations and cell survival in irradiated mammalian cells

International Nuclear Information System (INIS)

Tremp, J.

1981-01-01

A possible correlation between chromosome aberrations and reduced proliferation capacity or cell death was investigated. Synchronized Chinese hamster fibroblast cells were irradiated with 300 rad of x rays in early G 1 . Despite synchronization the cells reached the subsequent mitosis at different times. The frequency of chromosome aberrations was determined in the postirradiation division at 2-h intervals. The highest frequency occurred in cells with a first cell cycle of medium length. The colony-forming ability of mitotic cells was measured in parallel samples by following the progress of individual mitoses. The proportion of cells forming macrocolonies decreased with increasing cell cycle length, and the number of non-colony-forming cells increased. Irrespective of various first cell cycle lengths and different frequencies of chromosome aberrations, the number of cells forming microcolonies remained constant. A correlation was found between the absence of chromosome aberrations and the ability of cells to form macrocolonies. However, cells with a long first cell cycle formed fewer macrocolonies than expected

Design for an aberration corrected scanning electron microscope using miniature electron mirrors.

Science.gov (United States)

Dohi, Hideto; Kruit, Pieter

2018-06-01

Resolution of scanning electron microscopes (SEMs) is determined by aberrations of the objective lens. It is well known that both spherical and chromatic aberrations can be compensated by placing a 90-degree bending magnet and an electron mirror in the beam path before the objective lens. Nevertheless, this approach has not led to wide use of these aberration correctors, partly because aberrations of the bending magnet can be a serious problem. A mirror corrector with two mirrors placed perpendicularly to the optic axis of an SEM and facing each other is proposed. As a result, only small-angle magnetic deflection is necessary to guide the electron beam around the top mirror to the bottom mirror and around the bottom mirror to the objective lens. The deflection angle, in the order of 50 mrad, is sufficiently small to avoid deflection aberrations. In addition, lateral dispersion at the sample plane can be avoided by making the deflection fields symmetric. Such a corrector system is only possible if the incoming beam can pass the top mirror at a distance in the order of millimeters, without being disturbed by the electric fields of electrodes of the mirror. It is proposed that condition can be satisfied with micro-scale electron optical elements fabricated by using MEMS technology. In the proposed corrector system, the micro-mirrors have to provide the exact negative spherical and chromatic aberrations for correcting the aberration of the objective lens. This exact tuning is accomplished by variable magnification between the micro-mirrors and the objective lens using an additional transfer lens. Extensive optical calculations are reported. Aberrations of the micro-mirrors were analyzed by numerical calculation. Dispersion and aberrations of the deflectors were calculated by using an analytical field model. Combination aberrations caused by the off-axis position of dispersive rays in the mirrors and objective lens were also analyzed. It is concluded that the proposed

Electrostatic axisymmetric mirror with removable spherical aberration

International Nuclear Information System (INIS)

Birmuzaev, S.B.; Serikbaeva, G.S.; Hizirova, M.A.

1999-01-01

The electrostatic axisymmetric mirror, assembled from three coaxial cylinders with an equal diameter d and under the potential v1, v2 and v3, was computed. The proportions of geometrical and electric parameters of the mirror, with which the spherical 3-order aberration may be eliminated, were determined. The computation outcomes of the case, when the focal power of the mirror is enough large and the object plane in the focus is out of its field, are presented (Fig. 1 - potentials proportion that makes elimination of the spherical aberration possible; Fig. 2 - the focus coordinates when the spherical aberration is eliminated). The geometrical values are presented by d, and the electric ones are presented by v1. The figures on the curves present a length of the second (middle) electrode. The zero point is located in the middle of the gap between the first and second electrodes The investigated mirror may be used as a lens for the transmission electron microscope

An accurate optical design method for synchrotron radiation beamlines with wave-front aberration theory

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiaojiang, E-mail: slsyxj@nus.edu.sg; Diao, Caozheng; Breese, Mark B. H. [Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603 (Singapore)

2016-07-27

An aberration calculation method which was developed by Lu [1] can treat individual aberration term precisely. Spectral aberration is the linear sum of these aberration terms, and the aberrations of multi-element systems also can be calculated correctly when the stretching ratio, defined herein, is unity. Evaluation of focusing mirror-grating systems which are optimized according to Lu’s method, along with the Light Path Function (LPF) and the Spot Diagram method (SD) are discussed to confirm the advantage of Lu’s methodology. Lu’s aberration terms are derived from a precise wave-front treatment, whereas the terms of the power series expansion of the light path function do not yield an accurate sum of the aberrations. Moreover, Lu’s aberration terms can be individually optimized. This is not possible with the analytical spot diagram formulae.

Construction of special eye models for investigation of chromatic and higher-order aberrations of eyes.

Science.gov (United States)

Zhai, Yi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; He, Yuanqing; Chang, Shengjiang

2014-01-01

An achromatic element eliminating only longitudinal chromatic aberration (LCA) while maintaining transverse chromatic aberration (TCA) is established for the eye model, which involves the angle formed by the visual and optical axis. To investigate the impacts of higher-order aberrations on vision, the actual data of higher-order aberrations of human eyes with three typical levels are introduced into the eye model along visual axis. Moreover, three kinds of individual eye models are established to investigate the impacts of higher-order aberrations, chromatic aberration (LCA+TCA), LCA and TCA on vision under the photopic condition, respectively. Results show that for most human eyes, the impact of chromatic aberration on vision is much stronger than that of higher-order aberrations, and the impact of LCA in chromatic aberration dominates. The impact of TCA is approximately equal to that of normal level higher-order aberrations and it can be ignored when LCA exists.

Aberrant alternative splicing is another hallmark of cancer.

Science.gov (United States)

Ladomery, Michael

2013-01-01

The vast majority of human genes are alternatively spliced. Not surprisingly, aberrant alternative splicing is increasingly linked to cancer. Splice isoforms often encode proteins that have distinct and even antagonistic properties. The abnormal expression of splice factors and splice factor kinases in cancer changes the alternative splicing of critically important pre-mRNAs. Aberrant alternative splicing should be added to the growing list of cancer hallmarks.

Aberrant Alternative Splicing Is Another Hallmark of Cancer

OpenAIRE

Ladomery, Michael

2013-01-01

The vast majority of human genes are alternatively spliced. Not surprisingly, aberrant alternative splicing is increasingly linked to cancer. Splice isoforms often encode proteins that have distinct and even antagonistic properties. The abnormal expression of splice factors and splice factor kinases in cancer changes the alternative splicing of critically important pre-mRNAs. Aberrant alternative splicing should be added to the growing list of cancer hallmarks.

Screening of clonal chromosome aberrations present in A-bomb survivors by FISH method

International Nuclear Information System (INIS)

Nakano, Mimako; Kodama, Yoshiaki; Ito, Masahiro; Otaki, Kazuo; Nakamura, Nori

1997-01-01

Significance of FISH method for detection of clonal chromosome aberration was reviewed. A clonal chromosome aberration is derived from one abnormal cell clone and gives the influence on the frequency of the aberration. As well, the size and frequency of the aberration give an important information concerning lymphocyte kinetics. FISH method is meaningful for detection of the clonal aberration. Fifteen kinds of clonal aberrations were detected in A-bomb survivors, of which 10 were specifically detected by the method, indicating that its detection rate was 2-3 time as high as the ordinary method. The results were those on the DNA probe on no.1, no.2 and no.3 chromosomes, which consisting of about 23% of the genome. (K.H.)

Study of wavefront aberration in DR patients with different degree of dry eye

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Jin-Ran Fang

2018-05-01

Full Text Available AIM: To compare the changes of wavefront aberrations in patients with diabetic retinopathy(DRand with different degrees of dry eye and to explore the reasons of visual quality decline in them. METHODS: We randomly selected 40 eyes in our hospital for treatment with DR and varying degrees of dry eye, and 40 eyes of normal control group. Topcon KR-1W visual quality analyzer was used to record the mean square the total high order corneal aberration, spherical aberration, comatic aberration and trefoil aberration of cornea with pupil diameters of 4mm and 6mm. Analysis of variance were used to compare the wavefront aberrations and the aberration values in the control group and in patients with diabetic retinopathy and with different degrees of dry eye. RESULTS: For 4mm and 6mm pupil diameters, nondiabetic retinopathy(NDRwith dry eye group, the nonproliferative diabetic retinopathy(NPDRwith dry eye group and proliferative diabetic retinopathy(PDRdry eye group had significantly increased tHOA, coma and trefoil compared with the contrast group(PPCONCLUSION: Dry eye of diabetic retinopathy with different degrees is closely related to the increase of wavefront aberration. Increased wavefront aberration may be one of the reasons to reduced visual quality in patients with diabetic retinopathy and with dry eye, and provide the basis for the decline of visual function of diabetic patients with dry eye.

Aberrant hepatic artery

International Nuclear Information System (INIS)

Konstam, M.A.; Novelline, R.A.; Athanasoulis, C.A.

1979-01-01

In a patient undergoing selective hepatic arteriography for suspected liver trauma, a nonopacified area of the liver, initially thought to represent a hepatic hematoma, was later discovered to be due to the presence of an accessory right hepatic artery arising from the superior mesenteric artery. This case illustrates the need for a search for aberrant vasculature whenever a liver hematoma is suspected on the basis of a selective hepatic arteriogram. (orig.) [de

Pathophysiology of MDS: genomic aberrations.

Science.gov (United States)

Ichikawa, Motoshi

2016-01-01

Myelodysplastic syndromes (MDS) are characterized by clonal proliferation of hematopoietic stem/progenitor cells and their apoptosis, and show a propensity to progress to acute myelogenous leukemia (AML). Although MDS are recognized as neoplastic diseases caused by genomic aberrations of hematopoietic cells, the details of the genetic abnormalities underlying disease development have not as yet been fully elucidated due to difficulties in analyzing chromosomal abnormalities. Recent advances in comprehensive analyses of disease genomes including whole-genome sequencing technologies have revealed the genomic abnormalities in MDS. Surprisingly, gene mutations were found in approximately 80-90% of cases with MDS, and the novel mutations discovered with these technologies included previously unknown, MDS-specific, mutations such as those of the genes in the RNA-splicing machinery. It is anticipated that these recent studies will shed new light on the pathophysiology of MDS due to genomic aberrations.

Frequency of primary amenorrhea due to chromosomal aberration

International Nuclear Information System (INIS)

Jabbar, S.

2004-01-01

Objective: To find out the frequency of primary amenorrhea due to chromosomal aberration and the different options available for management. Subjects and Methods: All patients with primary amenorrhea due to chromosomal aberrations were included in study. Patient's detailed history, general physical examination, presence or absence of secondary sexual characteristics, abdominal and pelvic examination finding were noted. Targeted investigations, including ultrasound, hormonal assay, buccal smear and karyotyping results were recorded. The management options were individually tailored with focus n psychological management. Results: Eighteen patients out of 30,000 patients were diagnosed as having primary amenorrhea. Six had primary amenorrhea due to chromosomal aberrations with the frequency of 0.02%. The age at presentation was 20 years and above in 50%. The most common cause was Turner's syndrome seen in 4 out of 6. The presenting symptoms were delay in onset of menstruation in 05 patients and primary infertility in 01 patient. Conclusion: Primary amenorrhea due to chromosomal aberration is an uncommon condition requiring an early and accurate diagnosis. Turner's syndrome is a relatively common cause of this condition. Management should be multi-disciplinary and individualized according to the patient's age and symptom at presentation. Psychological management is very important and counselling throughout treatment is recommended. (author)

An aberrant uterus: Case report | Ondieki | East African Medical ...

African Journals Online (AJOL)

A case of an aberrant uterus is presented and literature reviewed. The patient presented with abnormal uterine bleeding, left iliac fossa pain and was managed by excising the aberrant uterus. This case was an enigma as it didn't present in the classical way one with anomalies of the uterus would present. Despite ...

Related research on corneal higher-order aberrations after different ways refractive surgery

Directory of Open Access Journals (Sweden)

Shu-Xi He

2015-08-01

Full Text Available AIM:To evaluate the changes of corneal high-order aberration(including Coma, Spab, RMShafter laser in situ keratomileusis(LASIKwith femtosecond laser, sub-Bowman keratomileusis(SBKand laser epithelial keratomileusis(LASEK.METHODS: Of 82 myopic patients(164 eyes, 31 patients(62 eyeswere treated by FS-LASIK, 31 patients(62 eyeswere treated by SBK, 20 patients(40 eyeswere treated by LASEK. Sirius system was used for measuring the coma aberration, spherical aberration, and high order aberration at 1, 15d,1, 3mo after surgery.RESULTS: 1Vision: The uncorrected visual acuity of the three groups had no differences(P>0.05. 2Corneal aberrations: Three kinds of surgical procedure for patients with corneal aberration had significant impact. The C7, C8, C12 and RMSh of three groups were increased significantly(P0.05. The C7, C8, C12 and RMSh were not recovered to preoperative levels after 3mo. But the increase of patients after FS-LASIK was smaller than the other two groups, with statistical significance(P0.05.CONCLUSION: Compared with SBK and LASEK,FS-LASIK has better visual acuity in the early postoperative and corneal higher-order aberrations increase is relatively small.

Chromosome aberrations in Norwegian reindeer following the Chernobyl accident

International Nuclear Information System (INIS)

Røed, K.H.; Jacobsen, M.

1995-01-01

Chromosome analyses were carried out on peripheral blood lymphocytes of semi-domestic reindeer in Norway which had been exposed to varying amounts of radiocesium emanating from the Chernobyl accident. The sampling was done in the period 1987-1990. The material included 192 reindeer, originating from four herds in central Norway, an area considerably affected by fallout from the Chernobyl accident, and from three herds in northern Norway which was unaffected by fallout from the accident. Significant heterogeneity in the distribution of chromosome aberrations between herds was observed. The pattern of chromosome aberration frequencies between herds was not related to the variation in radiocesium exposure from the Chernobyl accident. Other factors than the Chernobyl accident appear therefore to be of importance for the distribution of aberration frequencies found among present herds. Within the most contaminated area the reindeer born in 1986 showed significantly more chromosome aberrations than those born both before and after 1986. This could suggest that the Chernobyl accident fallout created an effect particularly among calves, during the immediate post-accident period in the most exposed areas

Novel plumage aberrations in Paraguayan non-Passerine Birds, and the definition of a new plumage aberration unique to Psittacidae

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Paul Smith

2017-07-01

Full Text Available Anomalous plumage colourations are reported for three species of non-passerine birds from Paraguay, Limpkin (Aramaus guarauna; Aramidae, Nanday Parakeet (Nandayus nenday; Psittacidae, and the Little Woodpecker (Veniliornis passerinus; Picidae. A leucistic Limpkin is the first published report of a colour anomaly for the family Aramidae. The colour aberration in N. nenday is hypothesised to be a result of an excess of red psittacofulvin pigments, which are unique to the Psittacidae. Although the mechanisms causing this colour aberration remain unknown, we suggest the term psittacofulvism for the phenotypic effect observed.

Zernike phase spatial filter for measuring the aberrations

OpenAIRE

Svetlana N. Khonina; Victor V. Kotlyar; Dmitriy V. Kirsh

2015-01-01

To measure directly the wavefront aberration coefficients, we propose to use the multi8order diffractive element fitted with the set of Zernike polynomials. Polynomials of lowest degree describe defocusing (ametropy) and astigmatism. Coefficients of highest degree correspond to the spherical aberration of oblique rays that occurs as a consequence of misalignment of the crystalline lens and foveola, as well as deflection at the periphery of the crystalline lens. Mul^order elements allow severa...

Aberration compensation of an ultrasound imaging instrument with a reduced number of channels.

Science.gov (United States)

Jiang, Wei; Astheimer, Jeffrey P; Waag, Robert C

2012-10-01

Focusing and imaging qualities of an ultrasound imaging system that uses aberration correction were experimentally investigated as functions of the number of parallel channels. Front-end electronics that consolidate signals from multiple physical elements can be used to lower hardware and computational costs by reducing the number of parallel channels. However, the signals from sparse arrays of synthetic elements yield poorer aberration estimates. In this study, aberration estimates derived from synthetic arrays of varying element sizes are evaluated by comparing compensated receive focuses, compensated transmit focuses, and compensated b-scan images of a point target and a cyst phantom. An array of 80 x 80 physical elements with a pitch of 0.6 x 0.6 mm was used for all of the experiments and the aberration was produced by a phantom selected to mimic propagation through abdominal wall. The results show that aberration correction derived from synthetic arrays with pitches that have a diagonal length smaller than 70% of the correlation length of the aberration yield focuses and images of approximately the same quality. This connection between correlation length of the aberration and synthetic element size provides a guideline for determining the number of parallel channels that are required when designing imaging systems that employ aberration correction.

Chromosome aberration studies and microdosimetry with radiations of varying quality

International Nuclear Information System (INIS)

Grillmaier, R.E.; Bihy, L.; Menzel, H.G.; Schuhmacher, H.

1978-01-01

To investigate the biological effectivity of complex irradiation fields encountered in radiation protection and high LET radiation therapy and to find meaningful specification of radiation quality closely related to the biological effectivity, correlated chromosome aberration studies and microdosimetric investigations have been carried out using cyclotron produced collimated fast neutrons. Human lymphocytes have been irradiated at different dose levels in the direct beam and in different positions in the penumbra and the rates of acentric fragments and dicentrics have been determined. In identical positions microdosimetric measurements have been performed. The dose relationship of aberration rates after irradiation in the direct beam, the aberration rates observed in the penumbra and the microdosimetric quantities ysub(D), ysub(F) and y* are presented and their relations are discussed. Furthermore the dose relationship of chromosome aberrations induced by 60 Co-γ-rays has been investigated and used to establish the RBE dose relationship of cyclotron neutrons

Assessing the construct validity of aberrant salience

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Kristin Schmidt

2009-12-01

Full Text Available We sought to validate the psychometric properties of a recently developed paradigm that aims to measure salience attribution processes proposed to contribute to positive psychotic symptoms, the Salience Attribution Test (SAT. The “aberrant salience” measure from the SAT showed good face validity in previous results, with elevated scores both in high-schizotypy individuals, and in patients with schizophrenia suffering from delusions. Exploring the construct validity of salience attribution variables derived from the SAT is important, since other factors, including latent inhibition/learned irrelevance, attention, probabilistic reward learning, sensitivity to probability, general cognitive ability and working memory could influence these measures. Fifty healthy participants completed schizotypy scales, the SAT, a learned irrelevance task, and a number of other cognitive tasks tapping into potentially confounding processes. Behavioural measures of interest from each task were entered into a principal components analysis, which yielded a five-factor structure accounting for ~75% percent of the variance in behaviour. Implicit aberrant salience was found to load onto its own factor, which was associated with elevated “Introvertive Anhedonia” schizotypy, replicating our previous finding. Learned irrelevance loaded onto a separate factor, which also included implicit adaptive salience, but was not associated with schizotypy. Explicit adaptive and aberrant salience, along with a measure of probabilistic learning, loaded onto a further factor, though this also did not correlate with schizotypy. These results suggest that the measures of learned irrelevance and implicit adaptive salience might be based on similar underlying processes, which are dissociable both from implicit aberrant salience and explicit measures of salience.

Retrospective Dose Reconstruction for Medical Diagnostic X Ray Workers in China using Stable Chromosome Aberrations

International Nuclear Information System (INIS)

Wang, Q.; Liu, P.; Li, J.; Wang, Q.; Tang, S.; Sun, M.; Wang, L.; Aoyama, T.; Sugahara, T.

1998-01-01

The chromosome rearrangements in medical diagnostic X ray workers were analysed using the G-banding technique and evaluated collectively in accumulated doses. A total of 9102 metaphase spreads from 84 medical diagnostic X ray workers and 17 controls were scored. The results showed that: (1) the frequencies of translocation, stable chromosome aberration and total aberration in X ray workers were significantly higher than those of controls (P < 0.05 γ 0.005), unstable chromosome aberrations (including dicentric and acentric aberration) tended upwards; (2) the main aberration in stable aberrations was reciprocal translocation; (3) the stable aberration predominated strikingly in total aberrations. The medical diagnostic X ray workers were divided into three groups according to calendar year of entry. The data showed that the frequencies of translocation, stable aberration and total aberration increased with earlier year of entry, especially in two groups who started working before 1970. According to the equation recommended by Straume et al, linear coefficient (α) in the linear quadratic model provided by Fernandez's experiment, their collective accumulation doses calculated were 0.53, 0.26 and 0.06 Gy for calendar year of entry before 1960, 1960-1969, and after 1970, in X ray workers, respectively. (author)

Single myelin fiber imaging in living rodents without labeling by deep optical coherence microscopy

Science.gov (United States)

Ben Arous, Juliette; Binding, Jonas; Léger, Jean-François; Casado, Mariano; Topilko, Piotr; Gigan, Sylvain; Claude Boccara, A.; Bourdieu, Laurent

2011-11-01

Myelin sheath disruption is responsible for multiple neuropathies in the central and peripheral nervous system. Myelin imaging has thus become an important diagnosis tool. However, in vivo imaging has been limited to either low-resolution techniques unable to resolve individual fibers or to low-penetration imaging of single fibers, which cannot provide quantitative information about large volumes of tissue, as required for diagnostic purposes. Here, we perform myelin imaging without labeling and at micron-scale resolution with >300-μm penetration depth on living rodents. This was achieved with a prototype [termed deep optical coherence microscopy (deep-OCM)] of a high-numerical aperture infrared full-field optical coherence microscope, which includes aberration correction for the compensation of refractive index mismatch and high-frame-rate interferometric measurements. We were able to measure the density of individual myelinated fibers in the rat cortex over a large volume of gray matter. In the peripheral nervous system, deep-OCM allows, after minor surgery, in situ imaging of single myelinated fibers over a large fraction of the sciatic nerve. This allows quantitative comparison of normal and Krox20 mutant mice, in which myelination in the peripheral nervous system is impaired. This opens promising perspectives for myelin chronic imaging in demyelinating diseases and for minimally invasive medical diagnosis.

Single myelin fiber imaging in living rodents without labeling by deep optical coherence microscopy.

Science.gov (United States)

Ben Arous, Juliette; Binding, Jonas; Léger, Jean-François; Casado, Mariano; Topilko, Piotr; Gigan, Sylvain; Boccara, A Claude; Bourdieu, Laurent

2011-11-01

Myelin sheath disruption is responsible for multiple neuropathies in the central and peripheral nervous system. Myelin imaging has thus become an important diagnosis tool. However, in vivo imaging has been limited to either low-resolution techniques unable to resolve individual fibers or to low-penetration imaging of single fibers, which cannot provide quantitative information about large volumes of tissue, as required for diagnostic purposes. Here, we perform myelin imaging without labeling and at micron-scale resolution with >300-μm penetration depth on living rodents. This was achieved with a prototype [termed deep optical coherence microscopy (deep-OCM)] of a high-numerical aperture infrared full-field optical coherence microscope, which includes aberration correction for the compensation of refractive index mismatch and high-frame-rate interferometric measurements. We were able to measure the density of individual myelinated fibers in the rat cortex over a large volume of gray matter. In the peripheral nervous system, deep-OCM allows, after minor surgery, in situ imaging of single myelinated fibers over a large fraction of the sciatic nerve. This allows quantitative comparison of normal and Krox20 mutant mice, in which myelination in the peripheral nervous system is impaired. This opens promising perspectives for myelin chronic imaging in demyelinating diseases and for minimally invasive medical diagnosis.

Relationship of DNA lesions and their repair to chromosomal aberration production

International Nuclear Information System (INIS)

Bender, M.A.

1979-01-01

Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers

Relationship of DNA lesions and their repair to chromosomal aberration production

Energy Technology Data Exchange (ETDEWEB)

Bender, M.A.

1979-01-01

Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers.

Low chromatic aberration hexapole for molecular state selection

International Nuclear Information System (INIS)

Ke, Yi; Deng, Xiao-Bing; Hu, Zhong-Kun

2016-01-01

In molecular beam state-selection experiments, the electrostatic hexapole acts as an optical lens, imaging molecules from the source to the focus. The molecular longitudinal velocity spread induces the phenomenon of chromatic aberration, which will reduce the state-selection purity. We propose a scheme which can effectively reduce the chromatic aberration by changing the hexapole voltage operating manner. The hexapole is already charged before molecules arrive at the entrance of the hexapole. When molecules are completely inside the hexapole, the voltage is switched off rapidly at an appropriate time. In this manner, faster molecules travel a longer hexapole focusing region than slower molecules. Therefore the focusing positions of molecules with different velocities become close. Numerical trajectory simulations of molecular state selection are carried out, and the results show that this low chromatic aberration hexapole can significantly improve the state purity from 46.2% to 87.0%. (paper)

An electron microscope for the aberration-corrected era

Energy Technology Data Exchange (ETDEWEB)

Krivanek, O.L. [Nion Co., 1102 8th Street, Kirkland, WA 98033 (United States)], E-mail: krivanek.ondrej@gmail.com; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W. [Nion Co., 1102 8th Street, Kirkland, WA 98033 (United States)

2008-02-15

Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown.

An electron microscope for the aberration-corrected era

International Nuclear Information System (INIS)

Krivanek, O.L.; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W.

2008-01-01

Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown

γ-ray induced chromosome aberration in rabbit peripheral blood lymphocytes irradiated in partial and whole body and decline of aberration rate with time post-exposure

International Nuclear Information System (INIS)

Zhang Lianzhen; Deng Zhicheng; Wang Haiyan

1997-01-01

Te author presents the results of study on 60 Co γ-ray induced chromosome aberration in rabbits peripheral blood lymphocytes irradiated in partial and whole body and the aberration rate decrease with the time of post-exposure. The experiments included 5 groups, it was whole-body exposure group, partial-body exposure (abdomen and pelvic cavity) group, blood irradiation group in vitro and control group respectively. Radiation dose was 3.0 Gy delivered at rate of 0.5 Gy/min. The results show that it was no significant differences between whole body and in blood irradiation group. The chromosome aberration yield in whole body exposure group was higher than that in partial-body group and in the abdomen exposure group was higher than in that in the pelvic cavity irradiation; The chromosome aberration rate decreased with the time of post-exposure in partial and whole body by γ-ray irradiation

Effects of SMILE and Trans-PRK on corneal higher order aberrations after myopic correction

Directory of Open Access Journals (Sweden)

Jiao Zhao

2018-02-01

Full Text Available AIM:To observe the effects of small incision lenticule extraction(SMILEand trans-epithelial photorefractive keratectomy(Trans-PRKon corneal horizontal coma, vertical coma, and spherical aberration and total higher order aberrations after refractive correction for myopia. METHODS: This was a prospective non-randomized cohort study. The cohort included 40 patients(80 eyeswith myopia, who received refraction correction surgery from December 2016 to February 2017 in Leshan Ophthalmic Center. Twenty patients(40 eyesreceived SMILE surgery and the other 20 patients(40 eyesreceived Trans-PRK surgery. Corneal aberrations were determined by a high-resolution Pentacam Scheimpflug camera before the surgery and at 1 and 3mo after the operation. Statistical analyses were performed using analysis of variance of repeated measures. RESULTS: At 1 and 3mo post-operation, the uncorrected visual acuity in both groups was better than or equal to the preoperative best corrected visual acuity. The preoperative corneal aberrations showed no significant difference between the two groups(P>0.05. Significantly higher aberration was found after the surgery in both groups(PP>0.05. Post-operation, horizontal and vertical coma had no significant difference between the two groups(P>0.05, while SMILE group showed lower spherical aberration and lower total higher order aberration than Trans-PRK group(PCONCLUSION: Both SMILE and Trans-PRK increase corneal aberration and their effects on horizontal and vertical coma are similar. However, SMILE has a minor influence on spherical aberration and total high order aberration than Trans-PRK.

Chromatin structure and ionizing-radiation-induced chromosome aberrations

International Nuclear Information System (INIS)

Muehlmann-Diaz, M.C.

1993-01-01

The possible influence of chromatic structure or activity on chromosomal radiosensitivity was studied. A cell line was isolated which contained some 10 5 copies of an amplified plasmid in a single large mosquito artificial chromosome (MAC). This chromosome was hypersensitive to DNase I. Its radiosensitivity was some three fold greater than normal mosquito chromosomes in the same cell. In cultured human cells irradiated during G 0 , the initial breakage frequency in chromosome 4, 19 and the euchromatic and heterochromatic portions of the Y chromosome were measured over a wide range of doses by inducing Premature Chromosome Condensation (PCC) immediately after irradiation with Cs-137 gamma rays. No evidence was seen that Y heterochromatin or large fragments of it remained unbroken. The only significant deviation from the expected initial breakage frequency per Gy per unit length of chromosome was that observed for the euchromatic portion of the Y chromosome, with breakage nearly twice that expected. The development of aberrations involving X and Y chromosomes at the first mitosis after irradation was also studied. Normal female cells sustained about twice the frequency of aberrations involving X chromosomes for a dose of 7.3 Gy than the corresponding male cells. Fibroblasts from individuals with supernumerary X chromosomes did not show any further increase in X aberrations for this dos. The frequency of aberrations involving the heterochromatic portion of the long arm of the Y chromosome was about what would be expected for a similar length of autosome, but the euchromatic portion of the Y was about 3 times more radiosensitive per unit length. 5-Azacytidine treatment of cultured human female fibroblasts or fibroblasts from a 49,XXXXY individual, reduced the methylation of cytosine residues in DNA, and resulted in an increased chromosomal radiosensitivity in general, but it did not increase the frequency of aberrations involving the X chromosomes

Estimation and Compensation of aberrations in Spatial Light Modulators

International Nuclear Information System (INIS)

Arias, Augusto; Castaneda, Roman

2011-01-01

The spatial light modulator (SLM) Holoeye LC-R720 is based on LCoS (Liquid Crystal on Silicon) technology. Due to the induced curvatures on the silicon plate by the production process, there are static aberrations in the wave-fronts modified by the SLM. In order to calculate the aberrated wave-front we used phase-shifting interferometry, an optimization algorithm for far field propagation, and the geometric characterization of the focal spot along the caustic. Zernike polynomials were used for expanding and comparing the wave-fronts. The aberration compensation was carried out by displaying the conjugated transmittance on the SLM. The complexity of the experimental setup and the requirements of the digital processing of each estimation method were comparatively analyzed.

Updating the lamellar hypothesis of hippocampal organization

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Robert S Sloviter

2012-12-01

Full Text Available In 1971, Andersen and colleagues proposed that excitatory activity in the entorhinal cortex propagates topographically to the dentate gyrus, and on through a trisynaptic circuit lying within transverse hippocampal slices or lamellae [Andersen, Bliss, and Skrede. 1971. Lamellar organization of hippocampal pathways. Exp Brain Res 13, 222-238]. In this way, a relatively simple structure might mediate complex functions in a manner analogous to the way independent piano keys can produce a nearly infinite variety of unique outputs. The lamellar hypothesis derives primary support from the lamellar distribution of dentate granule cell axons (the mossy fibers, which innervate dentate hilar neurons and area CA3 pyramidal cells and interneurons within the confines of a thin transverse hippocampal segment. Following the initial formulation of the lamellar hypothesis, anatomical studies revealed that unlike granule cells, hilar mossy cells, CA3 pyramidal cells, and Layer II entorhinal cells all form axonal projections that are more divergent along the longitudinal axis than the clearly lamellar mossy fiber pathway. The existence of pathways with translamellar distribution patterns has been interpreted, incorrectly in our view, as justifying outright rejection of the lamellar hypothesis [Amaral and Witter. 1989. The three-dimensional organization of the hippocampal formation: a review of anatomical data. Neuroscience 31, 571-591]. We suggest that the functional implications of longitudinally-projecting axons depend not on whether they exist, but on what they do. The observation that focal granule cell layer discharges normally inhibit, rather than excite, distant granule cells suggests that longitudinal axons in the dentate gyrus may mediate "lateral" inhibition and define lamellar function, rather than undermine it. In this review, we attempt a reconsideration of the evidence that most directly impacts the physiological concept of hippocampal lamellar

Nodular Hyperplasia Arising from the Lateral Aberrant Thyroid Tissue: A Case Report

International Nuclear Information System (INIS)

Jeong, Min Hye; Park, Jeong Seon; Lee, Young Jun

2012-01-01

The presence of aberrant thyroid tissue in the lateral neck is very rare. In addition, nodular hyperplasia in ectopic thyroid has rarely been reported. Due to the unusual location, the presence of lateral aberrant thyroid tissue could be misdiagnosed as a lymphadenopathy, neurogenic tumor, etc. We report on a case of nodular hyperplasia arising from the right lateral aberrant thyroid tissue.

Morphological alterations in newly born dentate gyrus granule cells that emerge after status epilepticus contribute to make them less excitable.

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Julián Tejada

Full Text Available Computer simulations of external current stimulations of dentate gyrus granule cells of rats with Status Epilepticus induced by pilocarpine and control rats were used to evaluate whether morphological differences alone between these cells have an impact on their electrophysiological behavior. The cell models were constructed using morphological information from tridimensional reconstructions with Neurolucida software. To evaluate the effect of morphology differences alone, ion channel conductances, densities and distributions over the dendritic trees of dentate gyrus granule cells were the same for all models. External simulated currents were injected in randomly chosen dendrites belonging to one of three different areas of dentate gyrus granule cell molecular layer: inner molecular layer, medial molecular layer and outer molecular layer. Somatic membrane potentials were recorded to determine firing frequencies and inter-spike intervals. The results show that morphologically altered granule cells from pilocarpine-induced epileptic rats are less excitable than control cells, especially when they are stimulated in the inner molecular layer, which is the target area for mossy fibers that sprout after pilocarpine-induced cell degeneration. This suggests that morphological alterations may act as a protective mechanism to allow dentate gyrus granule cells to cope with the increase of stimulation caused by mossy fiber sprouting.

Estrogen induces rapid decrease in dendritic thorns of CA3 pyramidal neurons in adult male rat hippocampus

International Nuclear Information System (INIS)

Tsurugizawa, Tomokazu; Mukai, Hideo

2005-01-01

Modulation of hippocampal synaptic plasticity by estrogen has been attracting much attention. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. Here we demonstrated the rapid effect of estradiol on the density of thorns of thorny excrescences, by imaging Lucifer Yellow-injected CA3 neurons in adult male rat hippocampal slices. The application of 1 nM estradiol induced rapid decrease in the density of thorns on pyramidal neurons within 2 h. The estradiol-mediated decrease in the density of thorns was blocked by CNQX (AMPA receptor antagonist) and PD98059 (MAP kinase inhibitor), but not by MK-801 (NMDA receptor antagonist). ERα agonist PPT induced the same suppressive effect as that induced by estradiol on the density of thorns, but ERβ agonist DPN did not affect the density of thorns. Note that a 1 nM estradiol treatment did not affect the density of spines in the stratum radiatum and stratum oriens. A search for synaptic ERα was performed using purified RC-19 antibody. The localization of ERα (67 kDa) in the CA3 mossy fiber terminals and thorns was demonstrated using immunogold electron microscopy. These results imply that estradiol drives the signaling pathway including ERα and MAP kinase

Chromosomal aberrations in Cynomolgus peripheral lymphocytes during and after fractionated whole-body γ-irradiation

International Nuclear Information System (INIS)

Guedeney, G.; Malarbet, J.L.; Doloy, M.T.

1989-01-01

Cynomolgus monkeys (Macaca fascicularis) were exposed to fractionated whole-body γ-irradiation at high and low dose rates for 4 or 5 weeks. The time-dependence of chromosomal aberrations was studied in relation to the number of lymphocytes during irradiation and after exposure for periods of up to about 600 days for chromosomal aberrations and 200 days for lymphocyte counts. Additivity of the daily effects on the number of chromosomal aberrations was observed during the exposures. Immediately after the end of the exposures the number of chromosomal aberrations decreased to reach low values. The disappearance of chromosomal aberrations seemed to be related to recovery of the lymphocyte counts. The data presented here emphasize the different kinetic patterns of chromosomal aberrations after fractionated and acute irradiation. (author)

A single subconvulsant dose of domoic acid at mid-gestation does not cause temporal lobe epilepsy in mice.

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Demars, Fanny; Clark, Kristen; Wyeth, Megan S; Abrams, Emily; Buckmaster, Paul S

2018-05-01

-control pilocarpine-treated mice, but seizure duration was similar. None of the mice treated in utero with vehicle or DA displayed hilar neuron loss or intense mossy fiber sprouting, a form of aberrant synaptic reorganization that develops in patients with temporal lobe epilepsy and in pilocarpine-treated mice. FVB mice that developed epilepsy (vehicle- and DA-treated) displayed mild mossy fiber sprouting. Results of this study suggest that a single subconvulsive dose of DA at mid-gestation does not cause temporal lobe epilepsy in mice. Copyright © 2018 Elsevier B.V. All rights reserved.

Angstrom analysis with dynamic in-situ aberration corrected electron microscopy

International Nuclear Information System (INIS)

Gai, P L; Boyes, E D

2010-01-01

Following the pioneering development of atomic resolution in-situ environmental TEM (ETEM) for direct probing of gas-solid reactions, recent developments are presented of dynamic real time in-situ studies at the Angstrom level in an aberration corrected electron microscope. The in-situ data from Pt-Pd nanoparticles on carbon with the corresponding FFT/optical diffractogram (OD) illustrate an achieved resolution of 0 C and higher, in a double aberration corrected JEOL 2200 FS TEM/STEM employing a wider gap objective pole piece and gas tolerant TMP column pumping system. Direct observations of dynamic biofuel catalysts under controlled calcinations conditions and quantified with catalytic reactivity and physico-chemical studies show the benefits in-situ aberration correction in unveiling the evolution of surface active sites necessary for the development efficient heterogeneous catalysts. The new results open up opportunities for dynamic studies of materials in an aberration corrected environment and direct future development activities.

Establishing working standards of chromosome aberrations analysis for biological dosimetry

International Nuclear Information System (INIS)

Bui Thi Kim Luyen; Tran Que; Pham Ngoc Duy; Nguyen Thi Kim Anh; Ha Thi Ngoc Lien

2015-01-01

Biological dosimetry is an dose assessment method using specify bio markers of radiation. IAEA (International Atomic Energy Agency) and ISO (International Organization for Standardization) defined that dicentric chromosome is specify for radiation, it is a gold standard for biodosimetry. Along with the documents published by IAEA, WHO, ISO and OECD, our results of study on the chromosome aberrations induced by radiation were organized systematically in nine standards that dealing with chromosome aberration test and micronucleus test in human peripheral blood lymphocytes in vitro. This standard addresses: the reference dose-effect for dose estimation, the minimum detection levels, cell culture, slide preparation, scoring procedure for chromosome aberrations use for biodosimetry, the criteria for converting aberration frequency into absorbed dose, reporting of results. Following these standards, the automatic analysis devices were calibrated for improving biological dosimetry method. This standard will be used to acquire and maintain accreditation of the Biological Dosimetry laboratory in Nuclear Research Institute. (author)

Low level dose induced chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Pohl-Rueling, J.

1992-01-01

Unstable structural aberrations in chromosomes of human blood lymphocytes cannot be used as biological dosemeters in the low dose range, when extrapolating from high doses using a linear dose response, as required by the original formula of the dual radiation action theory. A survey is given of experimental dose-response curves of chromosome aberrations, obtained in investigations not only by this institute, in cooperation with many other laboratories, but also by various authors in different areas of the world. The results are not compatible with the predicted linear dose relationships at in vivo dose ranges up to 30 mGy.y -1 . The aberration frequencies rise sharply with dose within the normal environmental exposure up to about twice that level. At higher doses, aberration frequencies increase less rapidly and reach a plateau. Some in vitro experiments of various authors with higher doses of low LET radiations, up to about 400 mGy have found dose responses with steps. (author)

Induction of chromosomal aberrations in human lymphocytes by fission neutrons

International Nuclear Information System (INIS)

Silva, Marcia Augusta da; Coelho, Paulo Rogerio Pinto; Bartolini, Paolo; Okazaki, Kayo

2009-01-01

Chromosome aberrations induced by sparsely ionizing radiation (low-LET) are well known and cytogenetic analyses of irradiated human lymphocytes have been widely applied to biological dosimetry. However, much less is known about chromosome aberrations induced by densely ionizing radiation (high LET), such as that of alpha particles or neutrons. Such particles induce DNA strand breaks, as well as chromosome breakage and rearrangements of high complexity. This damage is more localized and less efficiently repaired than after X- or γ-ray irradiation. This preferential production of complex aberrations by densely ionizing radiation is related to the unique energy deposition patterns, which produces highly localized multiple DNA damage at the chromosomal level. A better knowledge of the interactions between different types of radiation and cellular DNA is of importance, not only from the radiobiological viewpoint but also for dosimetric and therapeutic purposes. The objective of the present study was to analyse the cytogenetic effects of fission neutrons on peripheral blood lymphocytes in order to evaluate structural and numerical aberrations and number of cells in the different mitotic cycles. So, blood samples from five healthy donors, 22-25 years old, of both sexes, were irradiated in the Research Reactor IEA-R1 of our Institute (IPEN/CNEN-SP) with thermal and fast neutrons at doses of 0.2; 0.3; 0.5 and 1.0 Gy. The γ contribution to the total absorbed dose was about 30%. These doses were monitored by thermoluminescent dosemeters: LiF-600 (for neutrons) and LiF-700 (for γ-rays). The data concerning structural aberrations were evaluated with regard to three parameters: percentage of cells with aberrations, number of aberrations/cell and number of dicentric/cell. The cytogenetic results showed an increase in the three parameters after irradiation with neutrons, as a function of radiation dose. Apparently, there was no influence of neutrons on the kinetics of cellular

Aberrations of chromosome 8 in myelodysplastic syndromes: Clinical and biological significance

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Marisavljević Dragomir

2006-01-01

Full Text Available Introduction: Rearrangements of any single chromosome in human karyotype have been reported in patients with pMDS. Objective: To examine the role of aberrations of chromosome 8 in pathogenesis, clinical presentation and progression of myelodysplastic syndromes. Method: Cytogenetic analysis of bone marrow cells was carried out by direct method and by means of 24- and/or 48-hour unstimulated cell culture. Chromosomes were obtained by modified method of HG-bands. Results: On presentation, 109 out of 271 successfully karyotyped patients (40,2% had abnormal karyotypes. Among them, 22 patients (10.9% had aberrations of chromosome 8. Ten patients had trisomy 8 as "simple" aberration whilst additional three cases had trisomy 8 included in "complex" karyotypes (≥3 chromosomes. Cases with constitutional trisomy 8 mosaicism (CT8M were excluded using the chromosome analyses of PHA-stimulated blood cultures. On the contrary, monosomy (seven patients or deletion of chromosome 8 (two patients were exclusively found in "complex" karyotypes. During prolonged cytogenetic follow-up, trisomy 8 was not recorded in evolving karyotypes. In contrast, trisomy 8 disappeared in two cases during subsequent cytogenetic studies, i.e. 23 and 72 months from diagnosis, accompanied in one patient with complete hematological remission. No difference regarding age, sex, cytopenia, blood and marrow blast count or response to treatment was found between patients with trisomy 8 as the sole aberration compared to those with normal cytogenetics. Median survival of patients with trisomy 8 as the sole aberration was 27 months, as compared to 32 months in patients with normal cytogenetics (p=0.468, whilst median survival of patients with aberrations of chromosome 8 included in "complex" karyotypes was only 4 months. Conclusion: Aberrations of chromosome 8 are common in patients with pMDS. The presence of a clone with trisomy 8 is not always the sign of disease progression or poor

Corneal Aberrations in Former Preterm Infants: Results From The Wiesbaden Prematurity Study.

Science.gov (United States)

Fieß, Achim; Schuster, Alexander K; Kölb-Keerl, Ruth; Knuf, Markus; Kirchhof, Bernd; Muether, Philipp S; Bauer, Jacqueline

2017-12-01

To compare corneal aberrations in former preterm infants to that of full-term infants. A prospective cross-sectional study was carried out measuring the corneal shape with Scheimpflug imaging in former preterm infants of gestational age (GA) ≤32 weeks and full-term infants with GA ≥37 weeks now being aged between 4 to 10 years. The main outcome measures were corneal aberrations including astigmatism (Zernike: Z2-2; Z22), coma (Z3-1; Z31), trefoil (Z3-3; Z33), spherical aberration (Z40) and root-mean square of higher-order aberrations (RMS HOA). Multivariable analysis was performed to assess independent associations of gestational age groups and of retinopathy of prematurity (ROP) occurrence with corneal aberrations adjusting for sex and age at examination. A total of 259 former full-term and 226 preterm infants with a mean age of 7.2 ± 2.0 years were included in this study. Statistical analysis revealed an association of extreme prematurity (GA ≤28 weeks) with higher-order and lower-order aberrations of the total cornea. Vertical coma was higher in extreme prematurity (P prematurity rather than with ROP occurrence.

Measurement of specimen-induced aberrations of biological samples using phase stepping interferometry.

Science.gov (United States)

Schwertner, M; Booth, M J; Neil, M A A; Wilson, T

2004-01-01

Confocal or multiphoton microscopes, which deliver optical sections and three-dimensional (3D) images of thick specimens, are widely used in biology. These techniques, however, are sensitive to aberrations that may originate from the refractive index structure of the specimen itself. The aberrations cause reduced signal intensity and the 3D resolution of the instrument is compromised. It has been suggested to correct for aberrations in confocal microscopes using adaptive optics. In order to define the design specifications for such adaptive optics systems, one has to know the amount of aberrations present for typical applications such as with biological samples. We have built a phase stepping interferometer microscope that directly measures the aberration of the wavefront. The modal content of the wavefront is extracted by employing Zernike mode decomposition. Results for typical biological specimens are presented. It was found for all samples investigated that higher order Zernike modes give only a small contribution to the overall aberration. Therefore, these higher order modes can be neglected in future adaptive optics sensing and correction schemes implemented into confocal or multiphoton microscopes, leading to more efficient designs.

Effects of long-term radiation exposure on chromosomal aberrations in radiological technologists

International Nuclear Information System (INIS)

Kumagai, Etsuko; Onomichi, Mitsukazu; Tanaka, Ryuji; Kumagai, Takashi; Sawada, Shozo.

1990-01-01

Chromosomal aberrations in the lymphocytes of radiation technologists (RT) were analyzed by the trypsin G-banding method to study the late effects of long-term exposure to low doses of radiation. Structural aberrations were identified in 384 (2.5%) of 15442 cells analyzed from 53 RT as compared to 177 (1.6%) of 11136 cells from 36 healthy controls. Stable aberrations were the most frequent in both groups and were either translocations or deletions. Unstable aberrations were mainly acentric fragments in both groups. The frequency of translocations and acentric fragments was significantly higher in the RT than in the controls and was highest in the RT over 50 years. The highest frequency observed in the >50 age group was attributed to the unknown for cumulative dose prior to introduction of film badges. Frequency of chromosomal aberrations correlated with the estimated dose from the film badges and years of experience of each RT based on the equation y=0.22+0.37D+4.35D 2 , where y is overall frequency of chromosomal aberrations and D is the estimated radiation dose in Sv. (author)

Aberration analysis for freeform surface terms overlay on general decentered and tilted optical surfaces.

Science.gov (United States)

Yang, Tong; Cheng, Dewen; Wang, Yongtian

2018-03-19

Aberration theory helps designers to better understand the nature of imaging systems. However, the existing aberration theory of freeform surfaces has many limitations. For example, it only works in the special case when the central area of the freeform surface is used. In addition, the light footprint is limited to a circle, which does not match the case of an elliptical footprint for general systems. In this paper, aberrations generated by freeform surface term overlay on general decentered and tilted optical surfaces are analyzed. For the case when the off-axis section of a freeform surface is used, the aberration equation for using stop and nonstop surfaces is discussed, and the aberrations generated by Zernike terms up to Z 17/18 are analyzed in detail. To solve the problem of the elliptical light footprint for tilted freeform surfaces, the scaled pupil vector is used in the aberration analysis. The mechanism of aberration transformation is discovered, and the aberrations generated by different Zernike terms in this case are calculated. Finally we proposed aberration equations for freeform terms on general decentered and tilted freeform surfaces. The research result given in this paper offers an important reference for optical designers and engineers, and it is of great importance in developing analytical methods for general freeform system design, tolerance analysis, and system assembly.

Dentate gyrus network dysfunctions precede the symptomatic phase in a genetic mouse model of seizures

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Oana eToader

2013-08-01

Full Text Available Neuronal circuit disturbances that lead to hyperexcitability in the cortico-hippocampal network are one of the landmarks of temporal lobe epilepsy. The dentate gyrus (DG network plays an important role in regulating the excitability of the entire hippocampus by filtering and integrating information received via the perforant path. Here, we investigated possible epileptogenic abnormalities in the function of the DG neuronal network in the Synapsin II (Syn II knockout mouse (Syn II-/-, a genetic mouse model of epilepsy. Syn II is a presynaptic protein whose deletion in mice reproducibly leads to generalized seizures starting at the age of two months. We made use of a high-resolution microelectrode array (4096 electrodes and patch-clamp recordings, and found that in acute hippocampal slices of young pre-symptomatic (3-6 weeks-old Syn II-/- mice excitatory synaptic output of the mossy fibers is reduced. Moreover, we showed that the main excitatory neurons present in the polymorphic layer of the DG, hilar mossy cells, display a reduced excitability. We also provide evidence of a predominantly inhibitory regulatory output from mossy cells to granule cells, through feed-forward inhibition, and show that the excitatory-inhibitory ratio is increased in both pre-symptomatic and symptomatic Syn II-/- mice. These results support the key role of the hilar mossy neurons in maintaining the normal excitability of the hippocampal network and show that the late epileptic phenotype of the Syn II-/- mice is preceded by neuronal circuitry dysfunctions. Our data provide new insights into the mechanisms of epileptogenesis in the Syn II-/- mice and open the possibility for early diagnosis and therapeutic interventions.

The role of ethnic identity, self-concept, and aberrant salience in psychotic-like experiences.

Science.gov (United States)

Cicero, David C; Cohn, Jonathan R

2018-01-01

Social-cognitive models of psychosis suggest that aberrant salience and self-concept clarity are related to the development and maintenance of psychoticlike experiences (PLEs). People with high aberrant salience but low self-concept clarity tend to have the highest levels of PLEs. Ethnic identity may also be related to PLEs. The current research aimed to (a) replicate the interaction between aberrant salience and self-concept clarity in their association with PLEs in an ethnically diverse sample, (b) examine whether ethnic identity and aberrant salience interact in their association with PLEs, and (c) determine if self-concept clarity and ethnic identity independently interact with aberrant salience in their association with PLEs. An ethnically diverse group of undergraduates (n = 663) completed self-report measures of aberrant salience, self-concept clarity, ethnic identity, and PLEs. There was an interaction between aberrant salience and self-concept clarity such that people with high levels of aberrant salience and low levels of self-concept clarity had the highest levels of PLEs. Similarly, there was an interaction between aberrant salience and ethnic identity such that people with high aberrant salience but low ethnic identity had the highest PLEs. These interactions independently contributed to explaining variance in PLEs. This interaction was present for the Exploration but not Commitment subscales of ethnic identity. These results suggest that, in addition to low self-concept clarity, low ethnic identity may be a risk factor for the development of psychosis. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope.

Science.gov (United States)

Scholl, A; Marcus, M A; Doran, A; Nasiatka, J R; Young, A T; MacDowell, A A; Streubel, R; Kent, N; Feng, J; Wan, W; Padmore, H A

2018-05-01

Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast. Published by Elsevier B.V.

Circumflex coronary artery with aberrant origin and atherosclerosis

International Nuclear Information System (INIS)

Ozcan, E.; Bozlar, U.; Celik, T.; Tasar, M.

2012-01-01

Full text: Introduction: Circumflex (Cx) coronary artery congenital anomaly is reported to be less than 1% incidence. Coronary arteries with aberrant origin are more likely to have atherosclerosis according to some published literatures. Objectives and tasks: In this study we aim to present computed tomography (CT) angiography findings of a patient, who has Cx artery with aberrant origin and atherosclerotic. Materials and methods: 57-year-old woman without any symptoms who has risk factors to atherosclerosis was referred to our clinic for coronary CT angiography. Results: In CT angiography; we detected Cx coronary artery with aberrant origin (right sinus of valsalva) and retroaortic course. Also we saw intimal irregularities and calcified plaque causing severe narrowing in the proximal segment of artery. Right coronary and left anterior descendant arteries had mild atherosclerosis. Conclusion: Coroner CT angiography, which allows multiplanar imaging with high resolution, is an effective diagnostic tool for coronary artery disease, like not only congenital anomalies but also acquired atherosclerotic disease

Spherical aberration correction with threefold symmetric line currents.

Science.gov (United States)

Hoque, Shahedul; Ito, Hiroyuki; Nishi, Ryuji; Takaoka, Akio; Munro, Eric

2016-02-01

It has been shown that N-fold symmetric line current (henceforth denoted as N-SYLC) produces 2N-pole magnetic fields. In this paper, a threefold symmetric line current (N3-SYLC in short) is proposed for correcting 3rd order spherical aberration of round lenses. N3-SYLC can be realized without using magnetic materials, which makes it free of the problems of hysteresis, inhomogeneity and saturation. We investigate theoretically the basic properties of an N3-SYLC configuration which can in principle be realized by simple wires. By optimizing the parameters of a system with beam energy of 5.5keV, the required excitation current for correcting 3rd order spherical aberration coefficient of 400 mm is less than 1AT, and the residual higher order aberrations can be kept sufficiently small to obtain beam size of less than 1 nm for initial slopes up to 5 mrad. Copyright © 2015 Elsevier B.V. All rights reserved.

Aberrant PO2 values in proficiency testing.

Science.gov (United States)

Fonzi, C E; Clausen, J L; Mahoney, J

1993-03-01

We prospectively determined the frequency of aberrant vials of fluorocarbon/buffer used for proficiency testing of measurements of pH, PCO2, and PO2, using 20 duplicate vials from 12 lots of fluorocarbon/buffer and two arterial blood gas analyzers in eight reference laboratories. We defined aberrant vials as vials for which both duplicate measurements differed from the mean value of repeated measurements for the specific instrument (for each lot of testing materials) by > 0.04 for pH, > 10% of the mean or 3.0 mm Hg, whichever was greater, for PCO2; or > 10% of the mean or 6 mm Hg, whichever was greater, for PO2. Four of 1620 vials (0.25%) were aberrant, all based on PO2 measurements (range of mean values: pH, 7.181-7.631; PCO2, 12.7-65.9; PO2, 32.5-150.1) were 0.0055 for pH, 0.67 mm Hg for PCO2, and 1.65 mm Hg for PO2. Deliberate contamination of the fluorocarbon emulsion with room air, as might occur during sampling from the vial, indicated that only minor increases in PO2 (e.g., 1.0 mm Hg at PO2 of 56 mm Hg) occur when samples are aspirated. Larger increases in PO2 (mean 7.1 mm Hg at a PO2 of 66 mm Hg) occurred when the syringe samples were contaminated with room air. We conclude that isolated aberrant measurements of PO2 in blood gas proficiency testing attributable to vial contents can occur, but the frequency is very low.

Chromosome aberrations analysis of Serbia population from 1985 to 1995

International Nuclear Information System (INIS)

Jovicic, D.; Markovic, B.; Milacic, S.; Joksic, G.

1996-01-01

After the accident of NE Chernobyl in May 1986, Chernobyl's fallout with unhomogeneous dispersion of radioactive material in atmosphere caused the difference in contamination of the Serbia territory. The highest contamination was found to be in region Uzice, and the lowest in the region Nis. Two groups of population from these regions were undergone chromosome aberration analysis during 1987, 1988 and 1989. year. The results of our examination show increased frequency of structural chromosome aberrations/dicentrics, rings, peri centric inversions and acentric/ in the Uzice population, especially in the 1987. year. In 1985 and 1995 year have not been found chromosome aberrations. 2 refs.; 1 figs.; 2 tabs

Aberrant phenotypes in peripheral T cell lymphomas.

Science.gov (United States)

Hastrup, N; Ralfkiaer, E; Pallesen, G

1989-01-01

Seventy six peripheral T cell lymphomas were examined immunohistologically to test their reactivity with a panel of monoclonal antibodies against 11 T cell associated antigens (CD1-8, CD27, UCHL1, and the T cell antigen receptor). Sixty two (82%) lymphomas showed aberrant phenotypes, and four main categories were distinguished as follows: (i) lack of one or several pan-T cell antigens (49, 64% of the cases); (ii) loss of both the CD4 and CD8 antigens (11, 15% of the cases); (iii) coexpression of the CD4 and CD8 antigens (13, 17% of the cases); and (iv) expression of the CD1 antigen (eight, 11% of the cases). No correlation was seen between the occurrence of aberrant phenotypes and the histological subtype. It is concluded that the demonstration of an aberrant phenotype is a valuable supplement to histological assessment in the diagnosis of peripheral T cell lymphomas. It is recommended that the panel of monoclonal antibodies against T cell differentiation antigens should be fairly large, as apparently any antigen may be lost in the process of malignant transformation. Images Figure PMID:2469701

The Role of Aberrant Salience and Self-Concept Clarity in Psychotic-Like Experiences

Science.gov (United States)

Cicero, David C.; Becker, Theresa M.; Martin, Elizabeth A.; Docherty, Anna R.; Kerns, John G.

2013-01-01

Most theories of psychotic-like experiences posit the involvement of social-cognitive mechanisms. The current research examined the relations between psychotic-like experiences and two social-cognitive mechanisms, high aberrant salience and low self-concept clarity. In particular, we examined whether aberrant salience, or the incorrect assignment of importance to neutral stimuli, and low self-concept clarity interacted to predict psychotic-like experiences. The current research included three large samples (n = 667, 724, 744) of participants and over-sampled for increased schizotypal personality traits. In all three studies, an interaction between aberrant salience and self-concept clarity was found such that participants with high aberrant salience and low self-concept clarity had the highest levels of psychotic-like experiences. In addition, aberrant salience and self-concept clarity interacted to predict a supplemental measure of delusions in Study 2. In Study 3, in contrast to low self-concept clarity, neuroticism did not interact with aberrant salience to predict psychotic-like experiences, suggesting that the relation between low self-concept clarity and psychosis may not be due to neuroticism. Additionally, aberrant salience and self-concept clarity did not interact to predict to other schizotypal personality disorder criteria, social anhedonia or trait paranoia, which suggests the interaction is specific to psychotic-like experiences. Overall, our results are consistent with several social-cognitive models of psychosis suggesting that aberrant salience and self-concept clarity might be important mechanisms in the occurrence of psychotic-like symptoms. PMID:22452775

Synaptic glutamate spillover increases NMDA receptor reliability at the cerebellar glomerulus

OpenAIRE

Mitchell, Cassie S.; Lee, Robert H.

2011-01-01

Glutamate spillover in the mossy fiber to granule cell cerebellar glomeruli has been hypothesized to increase neurotransmission reliability. In this study, we evaluate this hypothesis using an experimentally-based quantitative model of glutamate spillover on the N-methyl-d-aspartate receptors (NMDA-Rs) at the cerebellar glomerulus. The transient and steady-state responses of NMDA-Rs were examined over a physiological range of firing rates. Examined cases included direct glutamate release acti...

JaK/STAT Inhibition to Prevent Post-Traumatic Epileptogenesis

Science.gov (United States)

2014-09-01

10 weeks post injury using Timm and Nissl staining (20 mice [subset of mice used in Task 1h]; months 20-21). Status: Not completed Accomplishments...using fluorescent immunohistochemistry with co- staining for cell specific markers (50 mice; Timeframe months 9-12). Status: Not completed...were treated with WP1066; 80 controls were used. 2. Timm staining did not revealed mossy fiber sprouting in any group at the early time-point, as

Primary chromatic aberration elimination via optimization work with genetic algorithm

Science.gov (United States)

Wu, Bo-Wen; Liu, Tung-Kuan; Fang, Yi-Chin; Chou, Jyh-Horng; Tsai, Hsien-Lin; Chang, En-Hao

2008-09-01

Chromatic Aberration plays a part in modern optical systems, especially in digitalized and smart optical systems. Much effort has been devoted to eliminating specific chromatic aberration in order to match the demand for advanced digitalized optical products. Basically, the elimination of axial chromatic and lateral color aberration of an optical lens and system depends on the selection of optical glass. According to reports from glass companies all over the world, the number of various newly developed optical glasses in the market exceeds three hundred. However, due to the complexity of a practical optical system, optical designers have so far had difficulty in finding the right solution to eliminate small axial and lateral chromatic aberration except by the Damped Least Squares (DLS) method, which is limited in so far as the DLS method has not yet managed to find a better optical system configuration. In the present research, genetic algorithms are used to replace traditional DLS so as to eliminate axial and lateral chromatic, by combining the theories of geometric optics in Tessar type lenses and a technique involving Binary/Real Encoding, Multiple Dynamic Crossover and Random Gene Mutation to find a much better configuration for optical glasses. By implementing the algorithms outlined in this paper, satisfactory results can be achieved in eliminating axial and lateral color aberration.

DNA Repair Defects and Chromosomal Aberrations

Science.gov (United States)

Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

2009-01-01

Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

Aberration compensation using a spatial light modulator LCD

International Nuclear Information System (INIS)

Amezquita, R; Rincon, O; Torres, Y M

2011-01-01

The dynamic correction of aberrations introduced in optical systems have been a widely discussed topic in the past 10 years. Adaptive optics is the most important developed field where the Shack-Hartmann sensors and deformable mirrors are used for the measurement and correction of wavefronts. In this paper, an interferometric set-up which uses a Spatial Light Modulator (SLM) as an active element is proposed. Using this SLM a procedure for the compensation of all phase aberrations present in the experimental setup is shown.

Ionizing radiation and frequency of chromosomal aberrations in exposed personnel

International Nuclear Information System (INIS)

Spasojevic-Tisma, Vera; Pavlovic, Snezana

2008-01-01

Full text: Frequencies of chromosomal aberrations in lymphocytes of peripheral blood were investigated among the observed groups of subjects who were exposed to low radiation doses (external exposure) in comparison with the control group. The first group of subjects is involved in the production of radioisotope technetium, whose accumulated work exposure time ranges between 3 and 30 years. The second group works on inspection of the medical X-ray equipment, whose accumulated work exposure time is between 2 and 34 years. The third group worked on decontamination of the terrain from depleted uranium radioactive ammunition. These workers were involved in mechanical removal of the surface soil layer to a depth of 50 cm. They were selected out of a group of professionals otherwise exposed to radiation from confined sources in their daily work. The accumulated work exposure of this group ranged from 2 to 34 years. The control group consisted of individuals not working in the ionizing radiation zone. The average yearly absorbed dose measured by TL dosimeters for all three observed groups did not exceed 2 mSv. The chromosomal aberrations were analyzed by a modified Moorhead method. The objective of the study was to establish the existence of differences in the frequencies of chromosomal aberrations change with respect to the source type, i.e. type of radioactive emission. Comparisons of the chromosomal changes in the observed groups revealed that the group working on technetium production had an increase in the frequency of chromosomal aberrations with respect to control. The aberrations found were of the acentric fragment and chromosomal break types. A comparison of the exposed groups between each other, no statistically significant differences in the numbers of chromosomal aberrations were found. Soil decontamination from depleted uranium did not contribute to the relative radiation risk, since it lasted only a few months, and was done by the professionals fully clothed

Chromosome aberrations in cultured skin cells obtained from atomic bomb survivors

International Nuclear Information System (INIS)

Honda, Takeo; Sadamori, Naoki.

1989-01-01

Skin specimens were obtained from 11 A-bomb survivors, 10 of whom had been exposed at ≤2300 m from the hypocenter, and 7 non-exposed controls. There was a higher frequency (12%, 147/1222 cells) of chromosome aberrations in the exposed group compared with 1.2% (4/341 cells) in the control group. This suggests that aberrant cells are still present in the skin tissue 40 years or more after the bombing. Of 147 cells, 136 cells (91.3%) showed translocation of chromosome. Other aberrations, such as inversion, deletion, dicentric chromosome and acentric fragment, were observed in only 3.8%. These aberrant cells tended to be observed in A-bomb survivors exposed to high doses and with a history of severe acute symptoms. One hundred and twenty two (83%) of 136 aberrant cells were obtained from 3 A-bomb survivors, which has important implications for marked proliferation of specific clone cells. In an analysis by B-band staining technique for the 122 cells, band sites of break point were found to correspond to loci of protooncogenes, suggesting the involvement in aggressive proliferation of clone cells. (Namekawa, K)

Aberrant Recapitulation of Developmental Program: Novel Target in Scleroderma

Science.gov (United States)

2015-12-01

AWARD NUMBER: W81XWH-12-1-0472 TITLE: “Aberrant Recapitulation of Developmental Program: Novel Target in Scleroderma ” PRINCIPAL INVESTIGATOR...SUBTITLE Aberrant Recapitulation of Developmental Program: Novel Target in Scleroderma 5a. CONTRACT NUMBER W81XWH-12-1-0472 5b. GRANT NUMBER 5c. PROGRAM...SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION / AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT Fibrosis in scleroderma is associated

Spherical aberration of an optical system and its influence on depth of focus.

Science.gov (United States)

Mikš, Antonín; Pokorný, Petr

2017-06-10

This paper analyzes the influence of spherical aberration on the depth of focus of symmetrical optical systems for imaging of axial points. A calculation of a beam's caustics is discussed using ray equations in the image plane and considering longitudinal spherical aberration as well. Concurrently, the influence of aberration coefficients on extremes of such a curve is presented. Afterwards, conditions for aberration coefficients are derived if the Strehl definition should be the same in two symmetrically placed planes with respect to the paraxial image plane. Such conditions for optical systems with large aberrations are derived with the use of geometric-optical approximation where the gyration diameter of the beam in given planes of the optical system is evaluated. Therefore, one can calculate aberration coefficients in such a way that the optical system generates a beam of rays that has the gyration radius in a given interval smaller than the defined limit value. Moreover, one can calculate the maximal depth of focus of the optical system respecting the aforementioned conditions.

Acute restraint stress decreases c-fos immunoreactivity in hilar mossy cells of the adult dentate gyrus

Science.gov (United States)

Moretto, Jillian N.; Duffy, Áine M.

2017-01-01

Although a great deal of information is available about the circuitry of the mossy cells (MCs) of the dentate gyrus (DG) hilus, their activity in vivo is not clear. The immediate early gene c-fos can be used to gain insight into the activity of MCs in vivo, because c-fos protein expression reflects increased neuronal activity. In prior work, it was identified that control rats that were perfusion-fixed after removal from their home cage exhibited c-fos immunoreactivity (ir) in the DG in a spatially stereotyped pattern: ventral MCs and dorsal granule cells (GCs) expressed c-fos protein (Duffy et al., Hippocampus 23:649–655, 2013). In this study, we hypothesized that restraint stress would alter c-fos-ir, because MCs express glucocorticoid type 2 receptors and the DG is considered to be involved in behaviors related to stress or anxiety. We show that acute restraint using a transparent nose cone for just 10 min led to reduced c-fos-ir in ventral MCs compared to control rats. In these comparisons, c-fos-ir was evaluated 30 min after the 10 min-long period of restraint, and if evaluation was later than 30 min c-fos-ir was no longer suppressed. Granule cells (GCs) also showed suppressed c-fos-ir after acute restraint, but it was different than MCs, because the suppression persisted for over 30 min after the restraint. We conclude that c-fos protein expression is rapidly and transiently reduced in ventral hilar MCs after a brief period of restraint, and suppressed longer in dorsal GCs. PMID:28190104

Outline of an ultracorrector compensating for all primary chromatic and geometrical aberrations of charged-particle lenses

International Nuclear Information System (INIS)

Rose, Harald

2004-01-01

A novel ultracorrector is outlined which compensates for the primary and secondary first-order chromatic aberrations and all third-order geometrical aberrations of electron optical systems with a straight axis. Owing to the imposed symmetry conditions on the fields and the paraxial fundamental rays, the corrector does not introduce aberrations with 2-fold symmetry. The chromatic aberrations are corrected by means of crossed electric magnetic quadrupoles while the third-order geometrical aberrations are eliminated by octopoles. By placing these elements at distinct positions within the corrector, it is possible to successively eliminate the third-order aberrations in such a way that each subsequent correction does not affect the aberrations corrected in the preceding correction steps

Measurement of eye aberrations in a speckle field

International Nuclear Information System (INIS)

Larichev, A V; Ivanov, P V; Iroshnikov, N G; Shmalgauzen, V I

2001-01-01

The influence of speckles on the performance of a Shark-Hartmann wavefront sensor is investigated in the eye aberration studies. The dependence of the phase distortion measurement error on the characteristic speckle size is determined experimentally. Scanning of the reference source was used to suppress the speckle structure of the laser beam scattered by the retina. The technique developed by us made it possible to study the time dependence of the human eye aberrations with a resolution of 30 ms. (laser applications and other topics in quantum electronics)

Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation.

Science.gov (United States)

Carrascal, Carolina Amador; Aristizabal, Sara; Greenleaf, James F; Urban, Matthew W

2016-02-01

Elasticity is measured by shear wave elasticity imaging (SWEI) methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study, the effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency, and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using fast object-oriented C++ ultrasound simulator (FOCUS) and shear wave simulations using finite-element-model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results: The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40%-90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, and the resulting Pearson's correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (phase aberration and attenuation case), measured phase screen, (only phase aberration case), and FOCUS/FEM model (only attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation.

[Frequency of chromosome aberrations in residents of the Semipalatinsk Oblast].

Science.gov (United States)

Gubitskaia, E G; Akhmatullina, N B; Vsevolodov, E B; Bishnevskaia, S S; Sharipov, I K; Cherednichenko, O G

1999-06-01

Cytogenetic analysis of the population of the Beskaragai district of the Semipalatinsk oblast adjacent to the territory of the nuclear test site was conducted by means of an ecological genetic questionnaire and cytogenetic examination of metaphase chromosomes. An increase in the total mutation level in the region was observed. The frequency of chromosome aberrations among the population of the Beskaragai district (3.2%) was statistically significantly (about 1.5 times) higher than the background levels in the clear regions (from 1 to 2%). Furthermore, the frequency of aberrations in adolescents was comparable with that in the adults. The spectrum of chromosome aberrations pointed to a significant contribution of radiation component to the mutagenesis.

Canine urothelial carcinoma: genomically aberrant and comparatively relevant.

Science.gov (United States)

Shapiro, S G; Raghunath, S; Williams, C; Motsinger-Reif, A A; Cullen, J M; Liu, T; Albertson, D; Ruvolo, M; Bergstrom Lucas, A; Jin, J; Knapp, D W; Schiffman, J D; Breen, M

2015-06-01

Urothelial carcinoma (UC), also referred to as transitional cell carcinoma (TCC), is the most common bladder malignancy in both human and canine populations. In human UC, numerous studies have demonstrated the prevalence of chromosomal imbalances. Although the histopathology of the disease is similar in both species, studies evaluating the genomic profile of canine UC are lacking, limiting the discovery of key comparative molecular markers associated with driving UC pathogenesis. In the present study, we evaluated 31 primary canine UC biopsies by oligonucleotide array comparative genomic hybridization (oaCGH). Results highlighted the presence of three highly recurrent numerical aberrations: gain of dog chromosome (CFA) 13 and 36 and loss of CFA 19. Regional gains of CFA 13 and 36 were present in 97 % and 84 % of cases, respectively, and losses on CFA 19 were present in 77 % of cases. Fluorescence in situ hybridization (FISH), using targeted bacterial artificial chromosome (BAC) clones and custom Agilent SureFISH probes, was performed to detect and quantify these regions in paraffin-embedded biopsy sections and urine-derived urothelial cells. The data indicate that these three aberrations are potentially diagnostic of UC. Comparison of our canine oaCGH data with that of 285 human cases identified a series of shared copy number aberrations. Using an informatics approach to interrogate the frequency of copy number aberrations across both species, we identified those that had the highest joint probability of association with UC. The most significant joint region contained the gene PABPC1, which should be considered further for its role in UC progression. In addition, cross-species filtering of genome-wide copy number data highlighted several genes as high-profile candidates for further analysis, including CDKN2A, S100A8/9, and LRP1B. We propose that these common aberrations are indicative of an evolutionarily conserved mechanism of pathogenesis and harbor genes

Cancer biomarkers defined by autoantibody signatures to aberrant O-glycopeptide epitopes

DEFF Research Database (Denmark)

Wandall, Hans H; Blixt, Ola; Tarp, Mads A

2010-01-01

Autoantibodies to cancer antigens hold promise as biomarkers for early detection of cancer. Proteins that are aberrantly processed in cancer cells are likely to present autoantibody targets. The extracellular mucin MUC1 is overexpressed and aberrantly glycosylated in many cancers; thus, we evalua...

Impact of types of lymphocyte chromosomal aberrations on human cancer risk

DEFF Research Database (Denmark)

Hagmar, Lars; Strömberg, Ulf; Bonassi, Stefano

2004-01-01

The frequency of cells with structural chromosomal aberrations (CAs) in peripheral blood lymphocytes is the first genotoxicity biomarker that has shown an association with cancer risk. CAs are usually divided into chromosome-type (CSAs) and chromatid-type aberrations (CTAs), with different mechan...

Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

Science.gov (United States)

Jones, L; Nellist, P D

2014-05-01

In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Stable and unstable chromosomal aberrations in workers at nuclear waste repository

International Nuclear Information System (INIS)

Hadjidekova, V.; Atanasova, P.; Iovchev, M.; Agova, S.

2004-01-01

A cytogenetic analysis of chromosomal aberrations was performed on 15 workers from final nuclear waste repository 'Novi Han'. The frequency of chromosomal aberrations were estimated in peripheral blood lymphocytes by conventional staining with Giemza and fluorescent in situ hybridization staining (FISH) using DNA specific probes. The results are compared with a control group from the administrative staff of the radioactive storage. All persons were interviewed by a special questionnaire list for professional, medical, and social status. The comparison of the results does not show increase of the frequency of unstable chromosomal aberrations detected by conventional staining. The frequency of stable chromosomal aberrations detected by FISH were significantly higher in workers group than in controls, although the statistical significance is low. The results show that FISH test is found to be more sensitive than conventional chromosomal analysis as a cytogenetic monitor test of the occupationally exposed subjects. (authors)

Non-linear character of dose dependences of chromosome aberration frequency in radiation-damaged root

International Nuclear Information System (INIS)

Kravets, E.A.; Berezhnaya, V.V.; Sakada, V.I.; Rashidov, N.M.; Grodzinskij, D.M.; Kravets, E.A.; Berezhnaya, V.V.; Sakada, V.I.; Rashidov, N.M.; Grodzinskij, D.M.

2012-01-01

The dose dependences of the aberrant anaphases in the root meristem in 48 hours after the irradiation have non-linear character and a plateau in the region about 6-8 Gy. The plateau indicates the activation of recovery processes. In the plateau range, the level of damages for this genotype is 33% for aberrant anaphases (FAA), 2.3 aberrations per aberrant anaphase (A/AC), and 0.74 aberrations for the total number of anaphases. At 10 Gy, the dose curve forms the exponential region caused by the involvement of the large number of new cells with unrepaired damages in the mutation process. The increase of A/AC to 1.1 indicate the ''criticality'' of the meristem radiation damage.

Descriptive evaluation of chromosome aberrations in blood lymphocytes due to gamma-irradiation

International Nuclear Information System (INIS)

Medina III, F.S.; Gregorio, J.S.; Vinoya, P.C.; Panlaque, C.A.

1983-01-01

To induce and evaluate the effect of radiation among Filipinos, frequencies and types of ν-ray induced chromosome aberrations were studied with peripheral lymphocytes from 19 donors. Peripheral blood samples were irradiated at 0 Gray, 500 mGy, 1 Gy, 2 Gy, 3 Gy and 4 Gy. Irradiated blood samples were cultured by the same standard technique as that commonly used for human blood lymphocytes. Our observations showed that irradiation causes chromosomal aberration similar to effects observed in Caucasians. Our study confirm that irradiation causes an increase of the chromosome aberrations types normally found in the control (gaps, chromatid breaks and chromosome fragments) and can induce aberrations which are rarely observed in non-exposed individual (deletions, translocations, polycentrics, rings, and despiralizations). (author)

Chromosome aberration frequency in blood lymphocytes of animals with 239Pu lung burdens

International Nuclear Information System (INIS)

Brooks, A.L.; LaBauve, R.J.; McClellan, R.O.; Jensen, D.A.

1976-01-01

Other investigators have suggested a causal relationship between accidental 239 Pu exposures in man and the presence of chromosome aberrations in blood lymphocytes. For experimental assessment of this relationship, 16 rhesus monkeys and 171 Chinese hamsters were exposed to 239 PuO 2 aerosols and an additional five hamsters were injected with 239 Pu citrate, and the frequency of aberrations in blood lymphocyte was determined. Hamsters with the highest lung burden had a median survival time of about 80 days. No deaths occurred in any of the other treated hamsters or monkeys by 250 days after 239 Pu inhalation. Hamsters sacrificed at 30 days showed an increase in chromosome aberration frequency with increasing dose to lungs. By 120 days after inhalation, the aberration frequency in the controls was 0.012. The frequency in animals with doses that produced significant life shortening had decreased to 0.018 and to 0.032 aberration/cell in animals with lower doses. At 380 days after injection of 2 nCi of 239 Pu citrate per gram of body weight, hamster lymphocytes had an aberration frequency of 0.048 aberration/cell. The level of chromosome damage in the 239 PuO 2 -exposed monkeys at 30 and 90 days after inhalation was not different from that observed in controls. Possible reasons for differences between the experimental animal observations and findings in man are discussed

Explanation of test and assessment of chromosomal aberrations on occupational health examinations for radiation workers

International Nuclear Information System (INIS)

Lu Yumin; Fu Baohua; Han Lin; Wang Xi'ai; Zhao Fengling

2012-01-01

Test and Assessment of Chromosomal Aberrations on Occupational Health Examinations for Radiation Workers was formulated for standardizing analysis and outcome assessment of chromosomal aberrations on occupational health examinations for radiation workers. In order to provide experimental and theoretical basis for implementation and extension of this standard, this paper interpreted the standard comprehensively, including some existed problems that methods on detection and outcome assessment of chromosomal aberrations is not unified in different laboratories in China, and related criteria,laws and regulations at home and abroad are not fit for the detection of chromosomal aberrations for radiation workers very well; some introduction on methods of chromosomal slide preparation, discriminant analysis and outcome assessment of chromosomal aberration; and some influencing factors in the quality of chromosomal aberration detection. (authors)

Automatic phase aberration compensation for digital holographic microscopy based on deep learning background detection.

Science.gov (United States)

Nguyen, Thanh; Bui, Vy; Lam, Van; Raub, Christopher B; Chang, Lin-Ching; Nehmetallah, George

2017-06-26

We propose a fully automatic technique to obtain aberration free quantitative phase imaging in digital holographic microscopy (DHM) based on deep learning. The traditional DHM solves the phase aberration compensation problem by manually detecting the background for quantitative measurement. This would be a drawback in real time implementation and for dynamic processes such as cell migration phenomena. A recent automatic aberration compensation approach using principle component analysis (PCA) in DHM avoids human intervention regardless of the cells' motion. However, it corrects spherical/elliptical aberration only and disregards the higher order aberrations. Traditional image segmentation techniques can be employed to spatially detect cell locations. Ideally, automatic image segmentation techniques make real time measurement possible. However, existing automatic unsupervised segmentation techniques have poor performance when applied to DHM phase images because of aberrations and speckle noise. In this paper, we propose a novel method that combines a supervised deep learning technique with convolutional neural network (CNN) and Zernike polynomial fitting (ZPF). The deep learning CNN is implemented to perform automatic background region detection that allows for ZPF to compute the self-conjugated phase to compensate for most aberrations.

Chromosome aberrations induced by 135 MeV of carbon and neon beams by PRC

International Nuclear Information System (INIS)

Ohara, Hiroshi; Minamihisamatu, Masako; Kanai, Tatsuaki; Eguchi-Kasai, Kiyomi; Itsukaichi, Hiromi; Fukutsu, Kumiko; Yatagai, Fumio; Sato, Kohki.

1993-01-01

Radiation-induced chromosome aberration can be an indicator of the radiation lesions in irradiated cells. Many studies on chromosome aberration induced by X-ray and γ - ray have indicated that the dose response of the aberration can be fitted to a quadratic equation, Y = αD + βD 2 , and it becomes linear as the LET of beams increases. The main subject of this study was some quantification of chromosomal aberration induced by 135 MeV/n carbon and neon beams produced by the RRC, the operation of which increasingly became useful for the studies on heavy ion biology. The results will meet with some of the radiobiological features connected to the specific action of charged particles. The materials used, the experimental method and the results are reported. Four curves of the dose response for the production of dicentric and ring types of aberration induced by carbon and neon beams and four different dose average LETs are given. Aberration production rate became higher as LET increased. Chromosome aberration can be quantified as an indicator of radiation lesions in the case of high LET particle radiation. (K.I.)

Influence of atmospheric turbulence on the energy focusability of Gaussian beams with spherical aberration

International Nuclear Information System (INIS)

Deng, Jinping; Ji, Xiaoling

2014-01-01

By using the four-dimensional (4D) computer code of the time-dependent propagation of laser beams through atmospheric turbulence, the influence of atmospheric turbulence on the energy focusability of Gaussian beams with spherical aberration is studied in detail, where the mean-squared beam width, the power in the bucket (PIB), the β parameter and the energy Strehl ratio are taken as the characteristic parameters. It is shown that turbulence results in beam spreading, and the effect of spherical aberration on the beam spreading decreases due to turbulence. Gaussian beams with negative spherical aberration are more affected by turbulence than those with positive spherical aberration. For the negative spherical aberration case, the focus position moves to the source plane due to turbulence. It is mentioned that the influence of turbulence on the energy focusability defined by a certain energy (i.e. PIB = 63%) is very heavy when the negative spherical aberration is very heavy. On the other hand, the influence of turbulence on the energy focusability defined by the energy within a given bucket radius (i.e. mean-squared beam width) is heaviest when a certain negative spherical aberration coefficient is adopted. (papers)

Chromosome aberrations as a biological dosimeter in Thorotrast patients: dosimetric problems

International Nuclear Information System (INIS)

Kemmer, W.; Steinstraesser, A.; Muth, H.

1979-01-01

The results of chromosome aberration analyses in 68 Thorotrast patients are discussed. In all patients dicentric chromosome aberrations were found but the chromosome aberration rate neither corresponds with the calculated whole body activity or the estimated absorbed dose in the organs of the RHS nor with the radium-224-equivalent value calculated from the radon-220 activity measured in the expired air. From x-ray examinations and histologic studies of lymph nodes the conclusion is drawn that the microdose absorbed from one lymphocyte is not in relation to the mean absorbed RHS dose, calculated from biophysical measurements

Aberrant behavior and cognitive ability in preschool children

Directory of Open Access Journals (Sweden)

Bala Gustav

2007-01-01

Full Text Available The sample included 712 preschool boys and girls at the age of 4 to 7 years (mean 5.96 decimal years and standard deviation .96 from preschool institutions in Novi Sad, Sombor, Sremska Mitrovica and Bačka Palanka. Information concerning 36 indicators of aberrant behavior of the children were supplied by their parents, whereas their cognitive ability was tested by Raven’s progressive colored matrices. Based on factor analysis (promax method, four factors i.e. generators of aberrant behavior in children were singled out: aggression, anxiousness, dissociation, and hysteria, whose relations with cognitive functioning and age were also analyzed by factor analysis. Aberrant behavior and cognitive abilities show significant interrelatedness. Owing to orderly developed cognitive abilities, a child understands essence and reality of problems, realizes possibilities and manners of solving them, and succeeds in realizing successful psycho-social functioning. Developed cognitive abilities enable a child to recognize and understand her/his own reactions in different situations and develop manners of reacting, which leads to strengthening psycho-social safety and adapting behavior in accordance with her/his age and abilities.

Chromosome aberration assays in barley (Hordeum vulgare)

Energy Technology Data Exchange (ETDEWEB)

Constantin, M J [Univ. of Tennessee, Knoxville; Nilan, R A

1982-01-01

Barley is an exceellent organism for studies of induced chromosome aberrations because of its few (2n = 2x = 14) relatively large chromosomes. Root-tip and shoot-tip cells have been used extensively for the study of ionizing radiation-induced chromosome aberrations. The general procedures are well known, the technology is simple and easy to learn, and the assays are relatively quick and inexpensive. Both root tips and shoot tips can be used for the study of chemical mutagens as well as ionizing radiations. Pollen mother cells are well suited for studying the effects of mutagens on meiotic chromosomes. The literature review for the Gene-Tox Program reported on 61 chemicals tested for their effects on barley chromosomes. Of these, 90% were reported to be either positive or positive dose-related, while 7% were negative and 3% were questionable. Barley assays based on chromosomal aberrations are useful to detect the clastogenic potency of chemicals under laboratory conditions. Indications are that the data from barley can be used to corroborate data obtained from other organisms. Among the classes of chemicals assayed were: alcohols and phenols; alkaloids; epoxides; alkyl sulfates; amides and sulfonamides; aromatic amines; aryl halides; aziridines; alkenes; carbamates; hydroazides; nitroaromatics; nitrosamides; nitrosources; phenothiazines; and polycyclic aromatic hydrocarbons.

Study of chromosome aberrations on the workers occupationally exposed to thorium and rare earth mixed dust

International Nuclear Information System (INIS)

Zhang Wei; Wang Chunyan; Lv Huiming; Zhang Cuilan; Hao Shuxia; Su Xu; Jia Kejun; Liu Yufei

2008-01-01

Objective: To study the effect of thorium and rare earth mixed dust on chromosome aberrations in the lymphocytes of occupational exposed workers. Methods: Analyses of unstable chromosome aberrations on 53 occupational exposed workers and 58 control workers were carried out by the conventional Giemsa staining method. Fluorescence in situ hybridization method was performed to analyze the chromosome stable aberrations on 10 occupational exposed workers and l0 control workers. Results: The frequencies of chromosomal aberration cells, dicentrics plus rings, total aberrations in exposed workers were significantly higher than those in controls. No significant difference was found in the frequency of acentric aberrations between exposed and non-exposed workers. No significant difference was found in the frequency of translocations between exposed and non-exposed workers. Conclusions: Chronically occupational exposure to thorium and rare earth mixed dust can increase the induction of unstable chromosome aberration, but the increase of stable chromosome aberrations (translocation) can not be observed. (authors)

Delayed formation of chromosome aberrations in mouse pachytebne spermatocytes treated with triethylenemelamine (TEM)

International Nuclear Information System (INIS)

Generoso, W.M.; Krishna, M.; Sotomayor, R.E.; Cacheiro, N.L.A.

1977-01-01

Induction of chromosome aberrations in pachytene spermatocytes of mice by 2 mg/kg TEM was compared with induction by 400 R x rays. These doses induced comparably high dominant lethal effects in pachytene spermatocytes of mice. Cytological analysis at diakinesis-metaphase I stage showed that whereas 76.4% of the cells treated with x rays at pachytene stage had aberrations, the frequencies observed in two TEM experiments were only 0.8 and 2.2%. On the other hand, 5% of the progeny from TEM-treated pachytene spermatocytes were found to be translocation heterozygotes. This is the first report on the recovery of heritable translocations from treated spermatocytes of mice. The aberration frequencies observed for TEM in diakinesis-metaphase I were much too low to account for all the lethal mutations and heritable translocations. Thus, the formation of the bulk of aberrations induced by TEM in pachytene spermatocytes was delayed--a marked contrast to the more immediate formation of x-ray-induced aberrations. It is postulated that the formation of the bulk of TEM-induced aberrations in pachytene spermatocytes and in certain postmeiotic stages occurs sometime during spermiogenesis, and not through the operation of postfertilization pronuclear DNA synthesis

Persistence of radiation-induced chromosome aberrations in a long-term cell culture.

Science.gov (United States)

Duran, Assumpta; Barquinero, Joan Francesc; Caballín, María Rosa; Ribas, Montserrat; Barrios, Leonardo

2009-04-01

The aim of the present study was to evaluate the persistence of chromosome aberrations induced by X rays. FISH painting and mFISH techniques were applied to long-term cultures of irradiated cells. With painting, at 2 Gy the frequency of apparently simple translocations remained almost invariable during all the culture, whereas at 4 Gy a rapid decline was observed between the first and the second samples, followed by a slight decrease until the end of the culture. Apparently simple dicentrics and complex aberrations disappeared after the first sample at 2 and 4 Gy. By mFISH, at 2 Gy the frequency of complete plus one-way translocations remained invariable between the first and last sample, but at 4 Gy a 60% decline was observed. True incomplete simple translocations disappeared at 2 and 4 Gy, indicating that incompleteness could be a factor to consider when the persistence of translocations is analyzed. The analysis by mFISH showed that the frequency of complex aberrations and their complexity increased with dose and tended to disappear in the last sample. Our results indicate that the influence of dose on the decrease in the frequency of simple translocations with time postirradiation cannot be fully explained by the disappearance of true incomplete translocations and complex aberrations. The chromosome involvement was random for radiation-induced exchange aberrations and non-random for total aberrations. Chromosome 7 showed the highest deviations from expected, being less and more involved than expected in the first and last samples, respectively. Some preferential chromosome-chromosome associations were observed, including a coincidence with a cluster from radiogenic chromosome aberrations described in other studies.

Accuracy of modal wavefront estimation from eye transverse aberration measurements

Science.gov (United States)

Chyzh, Igor H.; Sokurenko, Vyacheslav M.

2001-01-01

The influence of random errors in measurement of eye transverse aberrations on the accuracy of reconstructing wave aberration as well as ametropia and astigmatism parameters is investigated. The dependence of mentioned errors on a ratio between the number of measurement points and the number of polynomial coefficients is found for different pupil location of measurement points. Recommendations are proposed for setting these ratios.

Correcting the Chromatic Aberration in Barrel Distortion of Endoscopic Images

Directory of Open Access Journals (Sweden)

Y. M. Harry Ng

2003-04-01

Full Text Available Modern endoscopes offer physicians a wide-angle field of view (FOV for minimally invasive therapies. However, the high level of barrel distortion may prevent accurate perception of image. Fortunately, this kind of distortion may be corrected by digital image processing. In this paper we investigate the chromatic aberrations in the barrel distortion of endoscopic images. In the past, chromatic aberration in endoscopes is corrected by achromatic lenses or active lens control. In contrast, we take a computational approach by modifying the concept of image warping and the existing barrel distortion correction algorithm to tackle the chromatic aberration problem. In addition, an error function for the determination of the level of centroid coincidence is proposed. Simulation and experimental results confirm the effectiveness of our method.

Structural analysis of γ radiation-induced chromosomal aberrations observed by atomic force microscopy

International Nuclear Information System (INIS)

Qu Shuang; Chen Ying; Ge Shili; Liu Xiulin; Zhou Pingkun; Zhang Sa; Zhang Detian

2003-01-01

Objective: To find a new method for the measurement of radiation-induced damage, the structures of normal chromosomes and 60 Co γ-ray-induced chromosomal aberration were analyzed by atomic force microscopy. Methods: Normal and irradiated chromosomes of human peripheral blood lymphocytes were prepared, then three-dimensional structure and height of chromosomes were analyzed by atomic force microscopy. Results: Three-dimensional structures of normal chromosomes and dicentric aberration in irradiated chromosomes were observed clearly. The data of chromosome height were helpful to recognizing the dicentric aberrations. Conclusion: Atomic force microscopy providing three-dimension image and linear measurement is a new and valuable tool for structural analysis of radiation-induced chromosomal aberrations

Studies on the chromosome aberrations and isozyme patterns in cancer patients treated with therapeutic radiation

International Nuclear Information System (INIS)

Kim, J.J.

1979-09-01

The chromosome aberration yield of peripheral blood lymphocytes obtained from cancer patients who had been locally irradiated with therapeutic radiation seems to be largely influenced by total dose, loss of cell with aberration, irradiation interval and dose per day. When treatment period from 7 to 21 days and total dose range from 1000 to 3000 rad, the aberration yield is considered to change according to total dose and accumulated effect by continued existence of damaged chromosomes. However, loss of cell with aberration might play important role in chromosome aberration yield of peripheral blood lymphocytes obtained from those who had received radiation above 3000 rad. In case that other conditions make little difference, dose per day and irradiation interval are looked upon as important factors in aberration yield of lymphocyte chromosomes

Chromosome aberrations in human lymphocytes exposed to tritiated water in vitro

International Nuclear Information System (INIS)

Bocian, E.; Ziemba-zak, B.; Rosiek, O.; Sablinski, J.

1978-01-01

The induction of chromosome aberrations in human peripheral blood lymphocytes by tritiated water or 180 kV X-rays in vitro was studied. Lymphocytes were exposed to various concentrations of HTO for 2 h or for 53 h. Chromosome and chromatid type aberrations were scored during the first mitotic division after stimulation with phytohaemagglutinin. For the analysis of the dose-response relationship the data were fitted by the method of least-squares to different models. After acute exposure to tritium β-rays and X-rays, the dicentrics + centric rings and terminal + interstitial deletions gave the best fit to the linear-quadratic function. However, data for these types of aberrations after 53 h exposure to HTO gave equally good fit to the linear and linear-quadratic functions. The best description of the dose-response relationship for chromatid aberrations is given by the linear model. In the system studied the RBE of tritium β-rays as compared to 180 KV X-rays was 1.17+-0.02. (Auth.)

Aberration measurement of projection optics in lithographic tools based on two-beam interference theory

International Nuclear Information System (INIS)

Ma Mingying; Wang Xiangzhao; Wang Fan

2006-01-01

The degradation of image quality caused by aberrations of projection optics in lithographic tools is a serious problem in optical lithography. We propose what we believe to be a novel technique for measuring aberrations of projection optics based on two-beam interference theory. By utilizing the partial coherent imaging theory, a novel model that accurately characterizes the relative image displacement of a fine grating pattern to a large pattern induced by aberrations is derived. Both even and odd aberrations are extracted independently from the relative image displacements of the printed patterns by two-beam interference imaging of the zeroth and positive first orders. The simulation results show that by using this technique we can measure the aberrations present in the lithographic tool with higher accuracy

Aberration measurement of projection optics in lithographic tools based on two-beam interference theory.

Science.gov (United States)

Ma, Mingying; Wang, Xiangzhao; Wang, Fan

2006-11-10

The degradation of image quality caused by aberrations of projection optics in lithographic tools is a serious problem in optical lithography. We propose what we believe to be a novel technique for measuring aberrations of projection optics based on two-beam interference theory. By utilizing the partial coherent imaging theory, a novel model that accurately characterizes the relative image displacement of a fine grating pattern to a large pattern induced by aberrations is derived. Both even and odd aberrations are extracted independently from the relative image displacements of the printed patterns by two-beam interference imaging of the zeroth and positive first orders. The simulation results show that by using this technique we can measure the aberrations present in the lithographic tool with higher accuracy.

Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

Science.gov (United States)

Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

2014-11-01

Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

Third-order aberration-free ion-optical system for an electromagnetic isotope separator

International Nuclear Information System (INIS)

Chavet, I.

1982-12-01

The essential qualities required of a production isotope separator are high output and high enrichment factor. For this purpose, the imaging system should have as little geometric aberration as possible. In the proposed system, consisting of a homogeneous sector-type analyzing magnet, the beam is crossed in the axial direction at the entrance boundary of the magnetic field and the incidence to this boundary is normal. It is shown that for this case all radial aberrations to the ''practical'' third order can be eliminated provided four optical conditions are satisfied: two related to heterogeneous aberration terms in addition to the two conditions related to the second and third order homogeneous aperture aberration terms. The resulting equations take into account the magnetic fringe-field effects to the third order. (author)

Chromosome aberrations induced by radiation. With special reference to possible relation between chromosome aberrations and carcinogenesis

Energy Technology Data Exchange (ETDEWEB)

Kamada, N [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

1980-02-01

Chromosome aberration seems to be one of the most conspicuous residual abnormalities recognizable in radiation-exposed persons for many years after exposure. Knowledge of the biological significance of these abnormalities seems to be necessary for understanding of the effect of radiation on humans, especially in relation to possible leukemic development. Cytogenetic studies were performed on the bone marrow cells, T and B lymphocytes, and fibroblasts in atomic bomb-survivors who were in apparent good health (105 cases), atomic bomb exposed patients who had prolonged periods of blood disorders which terminated in acute leukemia (8 cases), and who had no such abnormalities (6 cases). All patients with chronic myelocytic leukemia (CML) and a history of atomic bomb exposure showed Philadelphia chromosome, a characteristic chromosome abnormality for CML. The persistent chromosome aberrations of bone marrow cells, T and B lymphocytes found among the atomic bomb survivors with or without blood disorders may give some clue to solve the problems of carcinogenesis.

X-ray-induced chromosome aberrations in Down lymphocytes: an explanation of their increased sensitivity

International Nuclear Information System (INIS)

Preston, R.J.

1981-01-01

Unstimulated lymphocytes from individuals with Down Syndrome (trisomy 21) are more sensitive to the induction of dicentric and ring aberrations by X rays than normal lymphocytes. Several explanations involving the more rapid rejoining of X-ray--induced lesions in Down cells have been offered. It is shown here that the repair of the DNA damage converted into chromosome aberrations is more rapid in Down cells than normal cells. This more rapid repair results in a higher probability of producing chromosomes aberrations, and hence higher aberration frequencies in Down than normal cells

X-ray-induced chromosome aberrations in Down lymphocytes: an explanation of their increased sensitivity

International Nuclear Information System (INIS)

Preston, R.J.

1981-01-01

Unstimulated lymphocytes from individuals with Down Syndrome (trisomy 21) are more sensitive to the induction of dicentric and ring aberrations by X rays than normal lymphocytes. Several explanations involving the more rapid rejoining of X-ray-induced lesions in Down cells have been offered. It is shown here that the repair of the DNA damage converted into chromosome aberrations is more rapid in Down cells than normal cells. This more rapid repair results in a higher probability of producing chromosome aberrations, and hence higher aberration frequencies in Down than normal cells

Experimental demonstration of single-mode fiber coupling over relatively strong turbulence with adaptive optics.

Science.gov (United States)

Chen, Mo; Liu, Chao; Xian, Hao

2015-10-10

High-speed free-space optical communication systems using fiber-optic components can greatly improve the stability of the system and simplify the structure. However, propagation through atmospheric turbulence degrades the spatial coherence of the signal beam and limits the single-mode fiber (SMF) coupling efficiency. In this paper, we analyze the influence of the atmospheric turbulence on the SMF coupling efficiency over various turbulences. The results show that the SMF coupling efficiency drops from 81% without phase distortion to 10% when phase root mean square value equals 0.3λ. The simulations of SMF coupling with adaptive optics (AO) indicate that it is inevitable to compensate the high-order aberrations for SMF coupling over relatively strong turbulence. The SMF coupling efficiency experiments, using an AO system with a 137-element deformable mirror and a Hartmann-Shack wavefront sensor, obtain average coupling efficiency increasing from 1.3% in open loop to 46.1% in closed loop under a relatively strong turbulence, D/r0=15.1.

Conventional radiation-biological dosimetry using frequencies of unstable chromosome aberrations

International Nuclear Information System (INIS)

Ramalho, Adriana T.; Costa, Maria Lucia P.; Oliveira, Monica S.

1998-01-01

Frequency of chromosome aberrations detected by conventional cytogenetics is a very useful parameter in biological radiodosimetry. It can be used for estimating absorbed doses in individuals working with radioactive sources and individuals accidentally exposed to radiation. In the first case subjects wear physical dosimeters as a routine safety habit. The laboratory at the Institute of Radioprotection and Dosimetry (IRD, Brazil) has been using conventional cytogenetic analysis to complement data obtained by physical dosimetry since 1983. Until now, more than one hundred cases were investigated where individual physical dosimeters detected occupational exposure (above the safety limits allowed). In total, only 34% of these cases were confirmed by conventional cytogenetic dosimetry. Also, conventional cytogenetic analysis following the radiation accident of Goiania (Brazil) in 1987 have been used. Peripheral lymphocytes from 129 exposed or potentially exposed individuals were analyzed for the frequencies of unstable chromosomal aberrations (dicentrics, centric rings and acentrics fragments) to estimate absorbed radiation doses. During the emergency period, doses were estimated to help immediate medical treatment using in vitro calibration curves produced before the accident. Later on, doses were assessed once more using new in vitro calibration curves. A drawback of this technique is that unstable aberrations are lost after exposure. To investigate the mean lifespan of lymphocytes containing dicentric and ring aberrations, we have followed 15 victims of the Goiania accident over all these years. Results suggest that the disappearance of unstable aberrations is dose-dependent. This could explain the variation in the results found among studies in this field

Conventional radiation-biological dosimetry using frequencies of unstable chromosome aberrations

Energy Technology Data Exchange (ETDEWEB)

Ramalho, Adriana T.; Costa, Maria Lucia P.; Oliveira, Monica S. [Institute of Radioprotection and Dosimetry (IRD), National Commission of Nuclear Energy (CNEN), Av. Salvador Allende, Cx. P. 37750, Rio de Janeiro 22.780-160 (Brazil)

1998-08-03

Frequency of chromosome aberrations detected by conventional cytogenetics is a very useful parameter in biological radiodosimetry. It can be used for estimating absorbed doses in individuals working with radioactive sources and individuals accidentally exposed to radiation. In the first case subjects wear physical dosimeters as a routine safety habit. The laboratory at the Institute of Radioprotection and Dosimetry (IRD, Brazil) has been using conventional cytogenetic analysis to complement data obtained by physical dosimetry since 1983. Until now, more than one hundred cases were investigated where individual physical dosimeters detected occupational exposure (above the safety limits allowed). In total, only 34% of these cases were confirmed by conventional cytogenetic dosimetry. Also, conventional cytogenetic analysis following the radiation accident of Goiania (Brazil) in 1987 have been used. Peripheral lymphocytes from 129 exposed or potentially exposed individuals were analyzed for the frequencies of unstable chromosomal aberrations (dicentrics, centric rings and acentrics fragments) to estimate absorbed radiation doses. During the emergency period, doses were estimated to help immediate medical treatment using in vitro calibration curves produced before the accident. Later on, doses were assessed once more using new in vitro calibration curves. A drawback of this technique is that unstable aberrations are lost after exposure. To investigate the mean lifespan of lymphocytes containing dicentric and ring aberrations, we have followed 15 victims of the Goiania accident over all these years. Results suggest that the disappearance of unstable aberrations is dose-dependent. This could explain the variation in the results found among studies in this field

A new aberration-corrected, energy-filtered LEEM/PEEM instrument. I. Principles and design

International Nuclear Information System (INIS)

Tromp, R.M.; Hannon, J.B.; Ellis, A.W.; Wan, W.; Berghaus, A.; Schaff, O.

2010-01-01

We describe a new design for an aberration-corrected low energy electron microscope (LEEM) and photo electron emission microscope (PEEM), equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control over the chromatic and spherical aberration coefficients C c and C 3 , as well as the mirror focal length, to match and correct the aberrations of the objective lens. For LEEM (PEEM) the theoretical resolution is calculated to be ∼1.5 nm (∼4 nm). Unlike previous designs, this instrument makes use of two magnetic prism arrays to guide the electron beam from the sample to the electron mirror, removing chromatic dispersion in front of the mirror by symmetry. The aberration correction optics was retrofitted to an uncorrected instrument with a base resolution of 4.1 nm in LEEM. Initial results in LEEM show an improvement in resolution to ∼2 nm.

Heavy ion-induced chromosomal aberrations analyzed by fluorescence in situ hybridization

International Nuclear Information System (INIS)

Durante, M.; Gialanella, G.; Grossi, G.; Pugliese, M.; Cella, L.; Greco, O.; George, K.; Yang, T.C.

1997-01-01

We have investigated the effectiveness of heavy ions in the induction of chromosomal aberrations in mammalian cells by the recent technique of fluorescence in situ hybridization (FISH) with whole-chromosome probes. FISH-painting was used both in metaphase and interphase (prematurely condensed) chromosomes. The purpose of our experiments was to address the following problems: (a) the ratio of different types of aberrations as a function of radiation quality (search for biomarkers); (b) the ratio between aberrations scored in interphase and metaphase as a function of radiation quality (role of apoptosis); (c) differences between cytogenetic effects produced by different ions at the same LET (role of track structure). (orig./MG)

Heavy ion-induced chromosomal aberrations analyzed by fluorescence in situ hybridization

Energy Technology Data Exchange (ETDEWEB)

Durante, M; Gialanella, G; Grossi, G; Pugliese, M [Univ. ` ` Federico II` ` , Naples (Italy). Dept. of Physics; [INFN, Naples (Italy); Cella, L; Greco, O [Univ. ` ` Federico II` ` , Naples (Italy). Dept. of Physics; Furusawa, Y [NIRS, Chiba (Japan); George, K; Yang, T C [NASA Lyndon B. Johnson Space Center, Houston, TX (United States)

1997-09-01

We have investigated the effectiveness of heavy ions in the induction of chromosomal aberrations in mammalian cells by the recent technique of fluorescence in situ hybridization (FISH) with whole-chromosome probes. FISH-painting was used both in metaphase and interphase (prematurely condensed) chromosomes. The purpose of our experiments was to address the following problems: (a) the ratio of different types of aberrations as a function of radiation quality (search for biomarkers); (b) the ratio between aberrations scored in interphase and metaphase as a function of radiation quality (role of apoptosis); (c) differences between cytogenetic effects produced by different ions at the same LET (role of track structure). (orig./MG)

Chromosomal Aberrations in Monozygotic and Dizygotic Twins Versus Singletons in Denmark During 1968-2009

DEFF Research Database (Denmark)

Kristensen, Lone Krøldrup; Larsen, Lisbeth A; Fagerberg, Christina

2017-01-01

BACKGROUND: Hall (Embryologic development and monozygotic twinning. Acta Geneticae Medicae et Gemellologiae, Vol. 45, 1996, pp. 53-57) hypothesized that chromosomal aberrations can lead to monozygotic (MZ) twinning. However, twinning and chromosomal aberrations increase prenatal mortality and could...... reduce the prevalence of chromosomal aberrations in live-born twins. We compared prevalence proportion ratios (PPR) of chromosomal aberrations and trisomy 21 (T21) in live-born twins versus singletons born in Denmark during 1968-2009. METHODS: We linked the Danish Twin Registry and a 5% random sample...... of all singletons to the Danish Cytogenetic Central Register and calculated PPR adjusted for maternal age for MZ, dizygotic (DZ), and all twins versus singletons. Zygosity was based on questionnaires or genetic markers. RESULTS: No overall difference in risk of chromosomal aberrations or T21 in twins...

In vivo chromatic aberration in eyes implanted with intraocular lenses.

Science.gov (United States)

Pérez-Merino, Pablo; Dorronsoro, Carlos; Llorente, Lourdes; Durán, Sonia; Jiménez-Alfaro, Ignacio; Marcos, Susana

2013-04-12

To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-developed laser ray tracing (LRT) aberrometer was used to measure the optical aberrations, at 532 nm and 785 nm wavelengths. The monochromatic wave aberrations were described using a fifth-order Zernike polynomial expansion. The chromatic difference of focus was estimated as the difference between the equivalent spherical errors corresponding to each wavelength. Wave aberration measurements were highly reproducible. Except for the defocus term, no significant differences in high order aberrations (HOA) were found between wavelengths. The average chromatic difference of focus was 0.46 ± 0.15 diopters (D) in the Tecnis group, and 0.75 ± 0.12 D in the AcrySof group, and the difference was statistically significant (P Chromatic difference of focus in the AcrySof group was not statistically significantly different from the Longitudinal chromatic aberration (LCA) previously reported in a phakic population (0.78 ± 0.16 D). The impact of LCA on retinal image quality (measured in terms of Strehl ratio) was drastically reduced when considering HOA and astigmatism in comparison with a diffraction-limited eye, yielding the differences in retinal image quality between Tecnis and AcrySof IOLs not significant. LRT aberrometry at different wavelengths is a reproducible technique to evaluate the chromatic difference of focus objectively in eyes implanted with IOLs. Replacement of the crystalline lens by the IOL did not increase chromatic difference of focus above that of phakic eyes in any of the groups. The AcrySof group showed chromatic difference of focus values very similar to physiological values in

Effect of correction of aberration dynamics on chaos in human ocular accommodation.

Science.gov (United States)

Hampson, Karen M; Cufflin, Matthew P; Mallen, Edward A H

2013-11-15

We used adaptive optics to determine the effect of monochromatic aberration dynamics on the level of chaos in the accommodation control system. Four participants viewed a stationary target while the dynamics of their aberrations were either left uncorrected, defocus was corrected, or all aberrations except defocus were corrected. Chaos theory analysis was used to discern changes in the accommodative microfluctuations. We found a statistically significant reduction in the chaotic nature of the accommodation microfluctuations during correction of defocus, but not when all aberrations except defocus were corrected. The Lyapunov exponent decreased from 0.71 ± 0.07 D/s (baseline) to 0.55 ± 0.03 D/s (correction of defocus fluctuations). As the reduction of chaos in physiological signals is indicative of stress to the system, the results indicate that for the participants included in this study, fluctuations in defocus have a more profound effect than those of the other aberrations. There were no changes in the power spectrum between experimental conditions. Hence chaos theory analysis is a more subtle marker of changes in the accommodation control system and will be of value in the study of myopia onset and progression.

Axial geometrical aberration correction up to 5th order with N-SYLC.

Science.gov (United States)

Hoque, Shahedul; Ito, Hiroyuki; Takaoka, Akio; Nishi, Ryuji

2017-11-01

We present N-SYLC (N-fold symmetric line currents) models to correct 5th order axial geometrical aberrations in electron microscopes. In our previous paper, we showed that 3rd order spherical aberration can be corrected by 3-SYLC doublet. After that, mainly the 5th order aberrations remain to limit the resolution. In this paper, we extend the doublet to quadruplet models also including octupole and dodecapole fields for correcting these higher order aberrations, without introducing any new unwanted ones. We prove the validity of our models by analytical calculations. Also by computer simulations, we show that for beam energy of 5keV and initial angle 10mrad at the corrector object plane, beam size of less than 0.5nm is achieved at the corrector image plane. Copyright © 2017 Elsevier B.V. All rights reserved.

Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

Science.gov (United States)

Su, W-Y; Cong, W-W; Shu, Y-J; Wang, D; Xu, G-H; Guo, C-H

2013-07-08

The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

Use of M-FISH analysis of α-particle-induced chromosome aberrations for the assessment of chromosomal breakpoint distribution and complex aberration formation

International Nuclear Information System (INIS)

Anderson, R.M.; Sumption, N.D.; Papworth, D.G.; Goodhead, D.T.

2003-01-01

Double strand breaks (dsb) of varying complexity are an important class of damage induced after exposure to ionising radiation and are considered to be the critical lesion for the formation of radiation-induced chromosome aberrations. Assuming the basic principles of the 'Breakage and Reunion' theory, dsb represent 'breakage' and aberrations are produced from the illegitimate repair (reunion) of the resulting dsb free-'ends'. Numerous questions relate to this process, in particular, (1) do chromosomal breakpoint 'hot-spots' that represent sensitive sites for breakage and/or regions of preferential repair/mis-repair, exist? (2) Considering that individual chromosomes and chromosome regions occupy discrete territories in the interphase nucleus, could rearrangements between specific chromosomes reflect domain organisation at the time of damage? (3) Assuming the topological constraints imposed on chromatin are not dramatically influenced by the presence of dsb, then how do multiple 'ends' from different chromosomes proximally associate for mis-repair as complex chromosome aberrations? To address these questions, we have analysed the chromosome aberrations induced in peripheral blood lymphocytes after exposure to 0.5 Gy α -particles (mean of 1 α -particle/cell) using the technique of M-FISH. This technique 'paints' all the human chromosomes (excluding homologues) uniquely, allowing chromosomal mis-repair to be visualised as differential colour-junctions and in addition, enhanced DAPI banding enables gross breakpoint assignation of these colour junctions. To test for non-randomness, we are comparing the frequency of occurrence of breakpoints obtained up to now with the F98 glioma model our knowledbased on chromosome length. Similarly, the involvement of each chromosome relative to other chromosomes within individual rearrangements can be determined by assuming the volume of chromosome domains is also proportional to their length. The current data to be presented will

High-resolution TEM and the application of direct and indirect aberration correction

DEFF Research Database (Denmark)

Hetherington, Crispin J.D.; Chang, Lan-Yun Shery; Haigh, Sarah

2008-01-01

Aberration correction leads to a substantial improvement in the directly interpretable resolution of transmission electron microscopes. Correction of the aberrations has been achieved electron-optically through a hexapole-based corrector and also indirectly by computational analysis of a focal or...

Bilateral reorganization of the dentate gyrus in hippocampal sclerosis

Science.gov (United States)

Thom, M; Martinian, L; Catarino, C; Yogarajah, M; Koepp, M J.; Caboclo, L; Sisodiya, S M.

2009-01-01

Background: Hippocampal sclerosis (HS) is the most common surgical pathology associated with mesial temporal lobe epilepsy (MTLE). HS is typically characterized by mossy fiber sprouting (MFS) and reorganization of neuropeptide Y (NPY) fiber networks in the dentate gyrus. One potential cause of postoperative seizure recurrence following temporal lobe surgery may be the presence of seizure-associated bilateral hippocampal damage. We aimed to investigate patterns of hippocampal abnormalities in a postmortem series as identified by NPY and dynorphin immunohistochemistry. Methods: Analysis of dentate gyrus fiber reorganization, using dynorphin (to demonstrate MFS) and NPY immunohistochemistry, was carried out in a postmortem epilepsy series of 25 cases (age range 21–96 years). In 9 patients, previously refractory seizures had become well controlled for up to 34 years prior to death. Results: Bilateral MFS or abnormal NPY patterns were seen in 15 patients including those with bilateral symmetric, asymmetric, and unilateral HS by conventional histologic criteria. MFS and NPY reorganization was present in all classical HS cases, more variably in atypical HS, present in both MTLE and non-MTLE syndromes and with seizure histories of up to 92 years, despite seizure remission in some patients. Conclusion: Synaptic reorganization in the dentate gyrus may be a bilateral, persistent process in epilepsy. It is unlikely to be sufficient to generate seizures and more likely to represent a seizure-induced phenomenon. GLOSSARY AED = antiepileptic drug; CA1p = CA1-predominant hippocampal sclerosis; CHS = classical hippocampal sclerosis; EFG = end folium gliosis; EFS = end folium sclerosis; GCD = granule cell dispersion; GCL = granule cell layer; HS = hippocampal sclerosis; MFS = mossy fiber sprouting; MTLE = mesial temporal lobe epilepsy; NPY = neuropeptide Y; ROI = region of interest; SE = status epilepticus; TLE = temporal lobe epilepsy. PMID:19710404

Effect of third-order aberrations on dynamic accommodation.

Science.gov (United States)

López-Gil, Norberto; Rucker, Frances J; Stark, Lawrence R; Badar, Mustanser; Borgovan, Theodore; Burke, Sean; Kruger, Philip B

2007-03-01

We investigate the potential for the third-order aberrations coma and trefoil to provide a signed cue to accommodation. It is first demonstrated theoretically (with some assumptions) that the point spread function is insensitive to the sign of spherical defocus in the presence of odd-order aberrations. In an experimental investigation, the accommodation response to a sinusoidal change in vergence (1-3D, 0.2Hz) of a monochromatic stimulus was obtained with a dynamic infrared optometer. Measurements were obtained in 10 young visually normal individuals with and without custom contact lenses that induced low and high values of r.m.s. trefoil (0.25, 1.03 microm) and coma (0.34, 0.94 microm). Despite variation between subjects, we did not find any statistically significant increase or decrease in the accommodative gain for low levels of trefoil and coma, although effects approached or reached significance for the high levels of trefoil and coma. Theoretical and experimental results indicate that the presence of Zernike third-order aberrations on the eye does not seem to play a crucial role in the dynamics of the accommodation response.

Effects of Ethanol on the Cerebellum: Advances and Prospects.

Science.gov (United States)

Luo, Jia

2015-08-01

Alcohol abuse causes cerebellar dysfunction and cerebellar ataxia is a common feature in alcoholics. Alcohol exposure during development also impacts the cerebellum. Children with fetal alcohol spectrum disorder (FASD) show many symptoms associated specifically with cerebellar deficits. However, the cellular and molecular mechanisms are unclear. This special issue discusses the most recent advances in the study of mechanisms underlying alcoholinduced cerebellar deficits. The alteration in GABAA receptor-dependent neurotransmission is a potential mechanism for ethanol-induced cerebellar dysfunction. Recent advances indicate ethanol-induced increases in GABA release are not only in Purkinje cells (PCs), but also in molecular layer interneurons and granule cells. Ethanol is shown to disrupt the molecular events at the mossy fiber - granule cell - Golgi cell (MGG) synaptic site and granule cell parallel fibers - PCs (GPP) synaptic site, which may be responsible for ethanol-induced cerebellar ataxia. Aging and ethanol may affect the smooth endoplasmic reticulum (SER) of PC dendrites and cause dendritic regression. Ethanol withdrawal causes mitochondrial damage and aberrant gene modifications in the cerebellum. The interaction between these events may result in neuronal degeneration, thereby contributing to motoric deficit. Ethanol activates doublestranded RNA (dsRNA)-activated protein kinase (PKR) and PKR activation is involved ethanolinduced neuroinflammation and neurotoxicity in the developing cerebellum. Ethanol alters the development of cerebellar circuitry following the loss of PCs, which could result in modifications of the structure and function of other brain regions that receive cerebellar inputs. Lastly, choline, an essential nutrient is evaluated for its potential protection against ethanol-induced cerebellar damages. Choline is shown to ameliorate ethanol-induced cerebellar dysfunction when given before ethanol exposure.

Selective corneal optical aberration (SCOA) for customized ablation

Science.gov (United States)

Jean, Benedikt J.; Bende, Thomas

2001-06-01

Wavefront analysis still have some technical problems which may be solved within the next years. There are some limitations to use wavefront as a diagnostic tool for customized ablation alone. An ideal combination would be wavefront and topography. Meanwhile Selective Corneal Aberration is a method to visualize the optical quality of a measured corneal surface. It is based on a true measured 3D elevation information of a video topometer. Thus values can be interpreted either using Zernike polynomials or visualized as a so called color coded surface quality map. This map gives a quality factor (corneal aberration) for each measured point of the cornea.

Static telescope aberration measurement using lucky imaging techniques

Science.gov (United States)

López-Marrero, Marcos; Rodríguez-Ramos, Luis Fernando; Marichal-Hernández, José Gil; Rodríguez-Ramos, José Manuel

2012-07-01

A procedure has been developed to compute static aberrations once the telescope PSF has been measured with the lucky imaging technique, using a nearby star close to the object of interest as the point source to probe the optical system. This PSF is iteratively turned into a phase map at the pupil using the Gerchberg-Saxton algorithm and then converted to the appropriate actuation information for a deformable mirror having low actuator number but large stroke capability. The main advantage of this procedure is related with the capability of correcting static aberration at the specific pointing direction and without the need of a wavefront sensor.

A monochromatic, aberration-corrected, dual-beam low energy electron microscope.

Science.gov (United States)

Mankos, Marian; Shadman, Khashayar

2013-07-01

The monochromatic, aberration-corrected, dual-beam low energy electron microscope (MAD-LEEM) is a novel instrument aimed at imaging of nanostructures and surfaces at sub-nanometer resolution that includes a monochromator, aberration corrector and dual beam illumination. The monochromator reduces the energy spread of the illuminating electron beam, which significantly improves spectroscopic and spatial resolution. The aberration corrector utilizes an electron mirror with negative aberrations that can be used to compensate the aberrations of the LEEM objective lens for a range of electron energies. Dual flood illumination eliminates charging generated when a conventional LEEM is used to image insulating specimens. MAD-LEEM is designed for the purpose of imaging biological and insulating specimens, which are difficult to image with conventional LEEM, Low-Voltage SEM, and TEM instruments. The MAD-LEEM instrument can also be used as a general purpose LEEM with significantly improved resolution. The low impact energy of the electrons is critical for avoiding beam damage, as high energy electrons with keV kinetic energies used in SEMs and TEMs cause irreversible change to many specimens, in particular biological materials. A potential application for MAD-LEEM is in DNA sequencing, which demands imaging techniques that enable DNA sequencing at high resolution and speed, and at low cost. The key advantages of the MAD-LEEM approach for this application are the low electron impact energies, the long read lengths, and the absence of heavy-atom DNA labeling. Image contrast simulations of the detectability of individual nucleotides in a DNA strand have been developed in order to refine the optics blur and DNA base contrast requirements for this application. Copyright © 2013 Elsevier B.V. All rights reserved.

Reduction of coating induced polarization aberrations by controlling the polarization state variation

International Nuclear Information System (INIS)

Li, Yanghui; Shen, Weidong; Zheng, Zhenrong; Zhang, Yueguang; Liu, Xu; Hao, Xiang

2011-01-01

The mechanism of coating induced polarization state variation is analysed by the Jones matrix. Pauli spin matrices are used to establish the relationship between coating induced polarization state variation and polarization aberrations. To reduce coating induced polarization aberrations, we propose that δ = 0 and T s = T p at arbitrary incident angle should be appended as two additional optimization goals of optical coating design when the requirements of transmittance are met. Two typical anti-reflection (AR) coatings are designed and the polarization state variation induced by them is simulated. The MTF (modulation transfer function) calculated by polarization ray tracing is applied to evaluate the polarization aberrations of the practical lithography objective system with the two AR coatings. All the obtained results show that the coating induced polarization aberrations can be reduced by optimizing the angle dependent properties of the optical coating without additional optical elements

Chromosome aberrations of bone marrow cells in heavily exposed atomic bomb survivors

International Nuclear Information System (INIS)

Tanaka, Kimio; Kamada, Nanao; Kuramoto, Atsushi; Ohkita, Takeshi

1986-01-01

Seven hundred and ten bone marrow cells from 13 A-bomb survivors, who were heavily exposed to atomic radiation, were examined using chromosome banding method. An average frequency of chromosome aberrations was 17 %. The most common structural abnormality was translocation (47 %), followed by complex aberrations involving three or more chromosomes (32 %). These abnormalities were frequently seen in A-bomb survivors exposed to estimated doses of 3.5 - 4.0 Gy. Eighty two percent of the structural aberrations were stable. Diploid cells were seen in 0.4 % and tetraploid cells were seen in 0.7 %. The frequency of breakpoint sites was high in chromosomes 1 and 17; while it was low in chromosomes 3, 6, 9, and 11. Abnormal clones were seen in one of the 13 survivors. Chromosome aberrations common to the bone marrow cells and peripheral lymphocytes were not seen in the same individual. (Namekawa, K.)

Aberrant ovarian artery arising from the common Iliac artery: Case report

Energy Technology Data Exchange (ETDEWEB)

Kim, Won Kyung [Dept. of Radiology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon (Korea, Republic of); Yang, Seung Boo; Lee, Jae Myeong [Dept. of Radiology, Soonchunhyang University Gumi Hospital, Soonchunhyang University College of Medicine, Gumi (Korea, Republic of); Goo, Dong Erk; Kim, Yong Jae; Chang, Yun Woo [Dept. of Radiology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul (Korea, Republic of)

2013-01-15

A 46-year-old Vietnamese woman received embolization therapy in order to control postpartum hemorrhage. Angiography revealed an aberrant ovarian artery arising from the right common iliac artery. Superselective catheterization and subsequent embolization of the aberrant ovarian artery and bilateral uterine arteries were performed. Precise knowledge of the anatomic variations of the ovarian artery is important for successful embolization.

Aberrant ovarian artery arising from the common Iliac artery: Case report

International Nuclear Information System (INIS)

Kim, Won Kyung; Yang, Seung Boo; Lee, Jae Myeong; Goo, Dong Erk; Kim, Yong Jae; Chang, Yun Woo

2013-01-01

A 46-year-old Vietnamese woman received embolization therapy in order to control postpartum hemorrhage. Angiography revealed an aberrant ovarian artery arising from the right common iliac artery. Superselective catheterization and subsequent embolization of the aberrant ovarian artery and bilateral uterine arteries were performed. Precise knowledge of the anatomic variations of the ovarian artery is important for successful embolization.

Measuring higher order optical aberrations of the human eye: techniques and applications

Directory of Open Access Journals (Sweden)

L. Alberto V. Carvalho

2002-11-01

Full Text Available In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia and higher order aberrations (coma, spherical aberration, etc.. We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.

Scaling laws for aberrations in magnetic quadrupole lens systems

International Nuclear Information System (INIS)

Moses, R.W.; Heighway, E.A.; Christian, R.S.; Dragt, A.J.

1987-01-01

A comparison has been made of the third-order (spherical) abberrations in magnetic quadrupole lenses for use in conventional charged particle beam transport systems. An analytical description of the abberrations is presented and this is compared with the results of high order numerical integration. The dependence of the aberration strength on the system geometry and f number is given and a comparison of doublet and triplet systems made. The reduction of the aberrations in both doublet and triplet systems using embedded magnetic octupole lenses is also discussed and analytical predictions are given

Papillary carcinoma in median aberrant thyroid (ectopic) - case report.

Science.gov (United States)

Hebbar K, Ashwin; K, Shashidhar; Deshmane, Vijaya Laxmi; Kumar, Veerendra; Arjunan, Ravi

2014-06-01

Median ectopic thyroid may be encountered anywhere from the foramen caecum to the diaphragm. Non lingual median aberrant thyroid (incomplete descent) usually found in the infrahyoid region and malignant transformation in this ectopic thyroid tissue is very rare. We report an extremely rare case of papillary carcinoma in non lingual median aberrant thyroid in a 25-year-old female. The differentiation between a carcinoma arising in the median ectopic thyroid tissue and a metastatic papillary carcinoma from an occult primary in the main thyroid gland is also discussed.

Two Fiber Optical Fiber Thermometry

Science.gov (United States)

Jones, Mathew R.; Farmer, Jeffery T.; Breeding, Shawn P.

2000-01-01

An optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber is essentially an isothermal cavity, so the emission from this cavity will be approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative heat flux at the end of the fiber at two wavelengths. The ratio of these measurements and Planck's Law are used to infer the temperature at the sensing tip. Optical fiber thermometers have high accuracy, excellent long-term stability and are immune to electromagnetic interference. In addition, they can be operated for extended periods without requiring re-calibration. For these reasons. it is desirable to use optical fiber thermometers in environments such as the International Space Station. However, it has recently been shown that temperature readings are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper will describe several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. The accuracy and sensitivity to measurement uncertainty will be presented for each method.

Comparison of monochromatic aberrations in young adults with different visual acuity and refractive errors.

Science.gov (United States)

Yazar, Seyhan; Hewitt, Alex W; Forward, Hannah; McKnight, Charlotte M; Tan, Alex; Mountain, Jenny A; Mackey, David A

2014-03-01

To compare the monochromatic aberrations in a large cohort of 20-year-old Australians with differing levels of visual acuity and explore the relationship between these aberrations and refractive error. Lions Eye Institute, Perth, Western Australia, Australia. Cross-sectional analysis of a population-based cohort. Monochromatic aberrations were measured using a Zywave II wavefront aberrometer with natural pupils in a dark room. The logMAR corrected distance visual acuity (CDVA) was measured monocularly under normal illumination. Cycloplegic autorefraction was also performed. The study enrolled 2039 eyes of 1040 participants. Data from 1007 right eyes were analyzed. The median CDVA and spherical equivalent were -0.06 logMAR (interquartile range [IQR], -0.10 to 0.00) and +0.25 diopters (D) (IQR, -0.38 to 0.63), respectively. The median 6.0 mm higher-order aberration (HOA) was 0.58 μm (IQR, 0.44 to 0.79). Coma-like aberrations and 3rd-, 4th-, and 5th-order HOAs were significantly different between subjects with a CDVA of -0.10 logMAR or better and those with a CDVA worse than -0.10 logMAR. Fourth-order aberrations Z(4,-4) (P=.024) and Z(4,-2) (P=.029) and 2nd-order aberration Z(2,0) (Peyes, emmetropic eyes, and hyperopic eyes. Subjects with higher myopia had slightly higher total HOAs. The HOAs in this population were marginally higher than previously reported values. The findings confirm there is a difference in monochromatic aberrations between different vision and refractive groups. Results in this study will benefit decision-making processes in the clinical setting. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Intrinsic factors that can affect sensitivity to chromosome-aberration induction

International Nuclear Information System (INIS)

Preston, R.J.

1982-01-01

The paper addresses the question, are there individuals who are hypersensitive, or are more likely to be hypersensitive, to the induction of chromosome aberrations by radiation and chemicals. Lymphocytes of persons heterozygous for xeroderma pigmentosum, ataxia telangiectasia, and Fauconi's anemia were subjected to chemical and/or ionizing radiations to determine their sensitivity to chromosome aberration induction. In the majority of cases the sensitivity was intermediate between that of normal individuals and homozygotes for these genes

Compensation of aberrations of deflected electron probe by means of dynamical focusing with stigmator

International Nuclear Information System (INIS)

Baba, Norio; Ebe, Toyoe; Ikehata, Koichi; Ito, Yasuhiro; Terada, Hiroshi

1979-01-01

Electron beam passing through a deflecting field is in general, subjected to aberrations such as distortion, astigmatism and coma in accordance with the deflecting angle. Accordingly the aberration defect of deflected beam is the most serious limiting factor in the performances of micromachining, microminiaturization and high resolution scanning electron microscopes. From many investigators' results, it is obvious that three important compensation methods to aberrations exist in principle, i.e., double deflection system, dynamical focusing, and the dynamical correction using a stigmator. In this paper, based on the aberration formula derived from the eikonal or the path method, the practical data of the aberration constants of deflected electron beam for the sequential deflection system with parallel plates are calculated, and using its result, the distorted spot patterns of an electron probe deflected in two-dimensional directions for various defocusings are graphically displayed by the aid of a computer. Further, by means of the dynamical focusing with a stigmator, the conditions to completely compensate the second order astigmatic aberration are derived, and spot patterns and the electron density distributions within the spots in the case when the compensating conditions are satisfied are also graphically displayed. (Wakatsuki, Y.)

Phenotypic characterization of aberrant stem and progenitor cell populations in myelodysplastic syndromes.

Science.gov (United States)

Ostendorf, Benjamin N; Flenner, Eva; Flörcken, Anne; Westermann, Jörg

2018-01-01

Recent reports have revealed myelodysplastic syndromes (MDS) to arise from cancer stem cells phenotypically similar to physiological hematopoietic stem cells. Myelodysplastic hematopoiesis maintains a hierarchical organization, but the proportion of several hematopoietic compartments is skewed and multiple surface markers are aberrantly expressed. These aberrant antigen expression patterns hold diagnostic and therapeutic promise. However, eradication of MDS requires targeting of early myelodysplasia propagating stem cells. This warrants an exact assessment of the differentiation stage at which aberrant expression occurs in transformed hematopoiesis. Here, we report results on the prospective and extensive dissection of the hematopoietic hierarchy in 20 patients with either low-risk MDS or MDS with excess blasts and compare it to hematopoiesis in patients with non-malignancy-associated cytopenia or B cell lymphoma without bone marrow infiltration. We found patients with MDS with excess blasts to exhibit characteristic expansions of specific immature progenitor compartments. We also identified the aberrant expression of several markers including ALDH, CLL-1, CD44, and CD47 to be specific features of hematopoiesis in MDS with excess blasts. We show that amongst these, aberrant CLL-1 expression manifested at the early uncommitted hematopoietic stem cell level, suggesting a potential role as a therapeutic target.

Phenotypic characterization of aberrant stem and progenitor cell populations in myelodysplastic syndromes.

Directory of Open Access Journals (Sweden)

Benjamin N Ostendorf

Full Text Available Recent reports have revealed myelodysplastic syndromes (MDS to arise from cancer stem cells phenotypically similar to physiological hematopoietic stem cells. Myelodysplastic hematopoiesis maintains a hierarchical organization, but the proportion of several hematopoietic compartments is skewed and multiple surface markers are aberrantly expressed. These aberrant antigen expression patterns hold diagnostic and therapeutic promise. However, eradication of MDS requires targeting of early myelodysplasia propagating stem cells. This warrants an exact assessment of the differentiation stage at which aberrant expression occurs in transformed hematopoiesis. Here, we report results on the prospective and extensive dissection of the hematopoietic hierarchy in 20 patients with either low-risk MDS or MDS with excess blasts and compare it to hematopoiesis in patients with non-malignancy-associated cytopenia or B cell lymphoma without bone marrow infiltration. We found patients with MDS with excess blasts to exhibit characteristic expansions of specific immature progenitor compartments. We also identified the aberrant expression of several markers including ALDH, CLL-1, CD44, and CD47 to be specific features of hematopoiesis in MDS with excess blasts. We show that amongst these, aberrant CLL-1 expression manifested at the early uncommitted hematopoietic stem cell level, suggesting a potential role as a therapeutic target.

On- and off-eye spherical aberration of soft contact lenses and consequent changes of effective lens power.

Science.gov (United States)

Dietze, Holger H; Cox, Michael J

2003-02-01

Soft contact lenses produce a significant level of spherical aberration affecting their power on-eye. A simple model assuming that a thin soft contact lens aligns to the cornea predicts that these effects are similar on-eye and off-eye. The wavefront aberration for 17 eyes and 33 soft contact lenses on-eye was measured with a Shack-Hartmann wavefront sensor. The Zernike coefficients describing the on-eye spherical aberration of the soft contact lens were compared with off-eye ray-tracing results. Paraxial and effective lens power changes were determined. The model predicts the on-eye spherical aberration of soft contact lenses closely. The resulting power change for a +/- 7.00 D spherical soft contact lens is +/- 0.5 D for a 6-mm pupil diameter and +/- 0.1 D for a 3-mm pupil diameter. Power change is negligible for soft contact lenses corrected for off-eye spherical aberration. For thin soft contact lenses, the level of spherical aberration and the consequent power change is similar on-eye and off-eye. Soft contact lenses corrected for spherical aberration in air will be expected to be aberration-free on-eye and produce only negligibly small power changes. For soft contact lenses without aberration correction, for higher levels of ametropia and large pupils, the soft contact lens power should be determined with trial lenses with their power and p value similar to the prescribed lens. The benefit of soft contact lenses corrected for spherical aberration depends on the level of ocular spherical aberration.

Excitatory and inhibitory pathways modulate kainate excitotoxicity in hippocampal slice cultures

DEFF Research Database (Denmark)

Casaccia-Bonnefil, P; Benedikz, Eirikur; Rai, R

1993-01-01

In organotypic hippocampal slice cultures, kainate (KA) specifically induces cell loss in the CA3 region while N-methyl-D-aspartate induces cell loss in the CA1 region. The sensitivity of slice cultures to KA toxicity appears only after 2 weeks in vitro which parallels the appearance of mossy...... fibers. KA toxicity is potentiated by co-application with the GABA-A antagonist, picrotoxin. These data suggest that the excitotoxicity of KA in slice cultures is modulated by both excitatory and inhibitory synapses....

Spontaneous and X-ray induced chromosomal aberrations in selected connective tissue diseases

International Nuclear Information System (INIS)

Burkhardt, W.C.; Jackson, J.F.; Songcharoen, S.; Meydrech, E.F.

1980-01-01

Chromosome studies were performed on peripheral blood lymphocytes of 28 patients with connective tissue disease (6 with progressive systemic sclerosis, 6 with systemic lupus erythematosus, 6 with anti-nuclear antibody positive rheumatoid arthritis, 6 with anti-nuclear antibody negative rheumatoid arthritis, and 4 with mixed connective tissue disease) and on 17 controls to determine the frequency of spontaneous as well as X-ray (75 rads) induced aberrations. The mean spontaneous chromosomal aberration frequency for the 28 patients (9.1%) was significantly (P=0.038) greater than that of controls (6.4%). When patients were categorized into specific clinically designated connective tissue disease subdivisions for comparison with the controls, only X-irradiated cells from the progressive systemic sclerosis group displayed significantly elevated levels of total chromosomal aberrations over those of the control group. The X-irradiated lymphocytes from these patients had an average of 23.6% aberrations per patient, while those of the control group showed an average of 14.9% per patient (P<0.05). (author)

Marginal estimator for the aberrations of a space telescope by phase diversity

Science.gov (United States)

Blanc, Amandine; Mugnier, Laurent; Idier, Jérôme

2017-11-01

In this communication, we propose a novel method for estimating the aberrations of a space telescope from phase diversity data. The images recorded by such a telescope can be degraded by optical aberrations due to design, fabrication or misalignments. Phase diversity is a technique that allows the estimation of aberrations. The only estimator found in the relevant literature is based on a joint estimation of the aberrated phase and the observed object. We recall this approach and study the behavior of this joint estimator by means of simulations. We propose a novel marginal estimator of the sole phase. it is obtained by integrating the observed object out of the problem; indeed, this object is a nuisance parameter in our problem. This reduces drastically the number of unknown and provides better asymptotic properties. This estimator is implemented and its properties are validated by simulation. its performance is equal or even better than that of the joint estimator for the same computing cost.

Spontaneous and X-ray induced chromosomal aberrations in selected connective tissue diseases

Energy Technology Data Exchange (ETDEWEB)

Burkhardt, W C; Jackson, J F; Songcharoen, S; Meydrech, E F [Mississippi Univ., Jackson (USA). Medical Center

1980-01-01

Chromosome studies were performed on peripheral blood lymphocytes of 28 patients with connective tissue disease (6 with progressive systemic sclerosis, 6 with systemic lupus erythematosus, 6 with anti-nuclear antibody positive rheumatoid arthritis, 6 with anti-nuclear antibody negative rheumatoid arthritis, and 4 with mixed connective tissue disease) and on 17 controls to determine the frequency of spontaneous as well as X-ray (75 rads) induced aberrations. The mean spontaneous chromosomal aberration frequency for the 28 patients (9.1%) was significantly (P=0.038) greater than that of controls (6.4%). When patients were categorized into specific clinically designated connective tissue disease subdivisions for comparison with the controls, only X-irradiated cells from the progressive systemic sclerosis group displayed significantly elevated levels of total chromosomal aberrations over those of the control group. The X-irradiated lymphocytes from these patients had an average of 23.6% aberrations per patient, while those of the control group showed an average of 14.9% per patient (P<0.05).

Brief history of the Cambridge STEM aberration correction project and its progeny

Energy Technology Data Exchange (ETDEWEB)

Brown, L. Michael [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Batson, Philip E. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics, Rutgers University, Piscataway, NJ 08854 (United States); Department of Materials Science, Rutgers University, Piscataway, NJ 08854 (United States); Dellby, Niklas [Nion Company, 11515 NE 118th Street, Kirkland, WA 98034 (United States); Krivanek, Ondrej L. [Nion Company, 11515 NE 118th Street, Kirkland, WA 98034 (United States); Department of Physics, Arizona State University, Tempe, AZ 85287 (United States)

2015-10-15

We provide a brief history of the project to correct the spherical aberration of the scanning transmission electron microscope (STEM) that started in Cambridge (UK) and continued in Kirkland (WA, USA), Yorktown Heights (NY, USA), and other places. We describe the project in the full context of other aberration correction research and related work, partly in response to the incomplete context presented in the paper “In quest of perfection in electron optics: A biographical sketch of Harald Rose on the occasion of his 80th birthday”, recently published in Ultramicroscopy. - Highlights: • We provide a brief history of the Cambridge project to correct the spherical aberration of the scanning transmission electron microscope (STEM). • We describe the project in the full context of other aberration correction work and related research. • We summarize our corrector development work that followed the Cambridge project, and which was the first to reach higher spatial resolution than any non-corrected electron microscope.

Brief history of the Cambridge STEM aberration correction project and its progeny

International Nuclear Information System (INIS)

Brown, L. Michael; Batson, Philip E.; Dellby, Niklas; Krivanek, Ondrej L.

2015-01-01

We provide a brief history of the project to correct the spherical aberration of the scanning transmission electron microscope (STEM) that started in Cambridge (UK) and continued in Kirkland (WA, USA), Yorktown Heights (NY, USA), and other places. We describe the project in the full context of other aberration correction research and related work, partly in response to the incomplete context presented in the paper “In quest of perfection in electron optics: A biographical sketch of Harald Rose on the occasion of his 80th birthday”, recently published in Ultramicroscopy. - Highlights: • We provide a brief history of the Cambridge project to correct the spherical aberration of the scanning transmission electron microscope (STEM). • We describe the project in the full context of other aberration correction work and related research. • We summarize our corrector development work that followed the Cambridge project, and which was the first to reach higher spatial resolution than any non-corrected electron microscope

Numerical correction of anti-symmetric aberrations in single HRTEM images of weakly scattering 2D-objects

International Nuclear Information System (INIS)

Lehtinen, Ossi; Geiger, Dorin; Lee, Zhongbo; Whitwick, Michael Brian; Chen, Ming-Wei; Kis, Andras; Kaiser, Ute

2015-01-01

Here, we present a numerical post-processing method for removing the effect of anti-symmetric residual aberrations in high-resolution transmission electron microscopy (HRTEM) images of weakly scattering 2D-objects. The method is based on applying the same aberrations with the opposite phase to the Fourier transform of the recorded image intensity and subsequently inverting the Fourier transform. We present the theoretical justification of the method, and its verification based on simulated images in the case of low-order anti-symmetric aberrations. Ultimately the method is applied to experimental hardware aberration-corrected HRTEM images of single-layer graphene and MoSe 2 resulting in images with strongly reduced residual low-order aberrations, and consequently improved interpretability. Alternatively, this method can be used to estimate by trial and error the residual anti-symmetric aberrations in HRTEM images of weakly scattering objects

Research development of thermal aberration in 193nm lithography exposure system

Science.gov (United States)

Wang, Yueqiang; Liu, Yong

2014-08-01

Lithographic exposure is the key process in the manufacture of the integrated circuit, and the performance of exposure system decides the level of microelectronic manufacture technology. Nowadays, the 193nm ArF immersion exposure tool is widely used by the IC manufacturer. With the uniformity of critical dimension (CDU) and overlay become tighter and the requirement for throughput become higher, the thermal aberration caused by lens material and structure absorbing the laser energy cannot be neglected. In this paper, we introduce the efforts and methods that researcher on thermal aberration and its control. Further, these methods were compared to show their own pros and cons. Finally we investigated the challenges of thermal aberration control for state of the art technologies.

Aberrant overian artery originating from the Ilolumbar artery: A case report

Energy Technology Data Exchange (ETDEWEB)

Lee, Ji Eun; Lee, Jae Myeong [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of)

2016-05-15

Here, we report a case of a 30-year-old woman who presented with primary postpartum hemorrhage due to uterine atony. She received uterine artery embolization (UAE). During left internal iliac arteriography, an aberrant left ovarian artery originating from the left iliolumbar artery was visualized. The aberrant left ovarian artery was connected to the left uterine artery via prominent collateral vessels. It supplied a significant amount of blood to the fundus of the uterus. Bilateral hypertrophied uterine arteries were embolized very carefully so that the embolic material did not reflux into the aberrant left ovarian artery. After the procedure, her vaginal bleeding was successfully controlled. Accurate understanding of anatomical variations of the ovarian artery is essential to avoid failure in controlling postpartum hemorrhage with UAE.

Aberrant overian artery originating from the Ilolumbar artery: A case report

International Nuclear Information System (INIS)

Lee, Ji Eun; Lee, Jae Myeong

2016-01-01

Here, we report a case of a 30-year-old woman who presented with primary postpartum hemorrhage due to uterine atony. She received uterine artery embolization (UAE). During left internal iliac arteriography, an aberrant left ovarian artery originating from the left iliolumbar artery was visualized. The aberrant left ovarian artery was connected to the left uterine artery via prominent collateral vessels. It supplied a significant amount of blood to the fundus of the uterus. Bilateral hypertrophied uterine arteries were embolized very carefully so that the embolic material did not reflux into the aberrant left ovarian artery. After the procedure, her vaginal bleeding was successfully controlled. Accurate understanding of anatomical variations of the ovarian artery is essential to avoid failure in controlling postpartum hemorrhage with UAE

Resection-Reconstruction of Aberrant Right Hepatic Artery During Whipple Procedure (Pancreaticoduodenectomy).

Science.gov (United States)

Sayyed, Raza; Rehman, Iffat; Niazi, Imran Khalid; Yusuf, Muhammed Aasim; Syed, Aamir Ali; V, Faisal

2016-06-01

Aberrant hepatic arterial anatomy poses a challenge for the surgeon during Whipple procedure. Intraoperative injury to the aberrant vasculature results in hemorrhagic or ischemic complications involving the liver and biliary tree. We report a case of replaced right hepatic artery arising from the superior mesenteric artery in a patient with periampullary carcinoma of the pancreas, undergoing pancreaticoduodenectomy. The aberrant artery was found to be coursing through the pancreatic parenchyma. This is a rare vascular anomaly. Resection of the arterial segment and end-to-end anastomosis was fashioned. Intrapancreatic course of the replaced right hepatic artery is a rare anomaly and is best managed by preoperative identification on radiology and meticulous intra-operative dissection and preservation. However, for an intrapancreatic course, resection and reconstruction may occasionally be required.

Chromosomal Aberrations in Humans Induced by Urban Air Pollution

DEFF Research Database (Denmark)

Knudsen, Lisbeth E.; Norppa, Hannu; Gamborg, Michael O.

1999-01-01

We have studied the influence of individual susceptibility factors on the genotoxic effects of urban air pollution in 106 nonsmoking bus drivers and 101 postal workers in the Copenhagen metropolitan area. We used the frequency of chromosomal aberrations in peripheral blood lymphocytes as a biomar......We have studied the influence of individual susceptibility factors on the genotoxic effects of urban air pollution in 106 nonsmoking bus drivers and 101 postal workers in the Copenhagen metropolitan area. We used the frequency of chromosomal aberrations in peripheral blood lymphocytes...... that long-term exposure to urban air pollution (with traffic as the main contributor) induces chromosome damage in human somatic cells. Low DNA repair capacity and GSTM1 and NAT2 variants associated with reduced detoxification ability increase susceptibility to such damage. The effect of the GSTM1 genotype......, which was observed only in the bus drivers, appears to be associated with air pollution, whereas the NAT2 genotype effect, which affected all subjects, may influence the individual response to some other common exposure or the baseline level of chromosomal aberrations....

Origin of specific chromosome aberration in radiation-induced leukemia

International Nuclear Information System (INIS)

Ban, Nobuhiko; Kai, Michiaki; Masuno, Yoko

2005-01-01

The theme in the title is discussed from the four aspects of specific chromosome aberration (sAb) patterns in radiation-induced leukemia (RIL), possibility for radiation to induce the sAb in RIL, any evidence for participation of delayed aberration to form sAb and the proportion of such healthy humans as having the specifically rearranged genome. Data of sAb observed in leukemia of 25 A-bomb survivors and of 38 patients post radiotherapy of cancers give a rather common pattern. However, many inconsistent results are obtained for sAb in patients post radiotherapy, A-bomb survivors, residents living in radio-contaminated houses in Taipei, in vitro exposure, and Chernobyl residents. At present, any clear evidence is available neither for sAb derived from the delayed aberration nor for estimating the proportion with the specifically rearranged gene. As above, it is unlikely that radiation induces such a translocation abnormality as BCR-ABL specifically seen in leukemia, and this aspect will be important for studies on the genesis of RIL and its risk assessment. (S.I.)

Quality factor of aberrated gaussian laser beams

CSIR Research Space (South Africa)

Mafusire, C

2010-09-01

Full Text Available 15 20 25 30 35 M 4 © CSIR 2010 www.csir.co.za Conclusion • Laser beam quality depends on - y-Astigmatism - y-Coma - x-Coma - y-Triangular astigmatism - x-Triangular astigmatism - Spherical aberration...

Optimum aberration coefficients for recording high-resolution off-axis holograms in a Cs-corrected TEM

Energy Technology Data Exchange (ETDEWEB)

Linck, Martin, E-mail: linck@ceos-gmbh.de [CEOS GmbH, Englerstr. 28, D-69126 Heidelberg (Germany)

2013-01-15

Amongst the impressive improvements in high-resolution electron microscopy, the Cs-corrector also has significantly enhanced the capabilities of off-axis electron holography. Recently, it has been shown that the signal above noise in the reconstructable phase can be significantly improved by combining holography and hardware aberration correction. Additionally, with a spherical aberration close to zero, the traditional optimum focus for recording high-resolution holograms ('Lichte's defocus') has become less stringent and both, defocus and spherical aberration, can be selected freely within a certain range. This new degree of freedom can be used to improve the signal resolution in the holographically reconstructed object wave locally, e.g. at the atomic positions. A brute force simulation study for an aberration corrected 200 kV TEM is performed to determine optimum values for defocus and spherical aberration for best possible signal to noise in the reconstructed atomic phase signals. Compared to the optimum aberrations for conventional phase contrast imaging (NCSI), which produce 'bright atoms' in the image intensity, the resulting optimum values of defocus and spherical aberration for off-axis holography enable 'black atom contrast' in the hologram. However, they can significantly enhance the local signal resolution at the atomic positions. At the same time, the benefits of hardware aberration correction for high-resolution off-axis holography are preserved. It turns out that the optimum is depending on the object and its thickness and therefore not universal. -- Highlights: Black-Right-Pointing-Pointer Optimized aberration parameters for high-resolution off-axis holography. Black-Right-Pointing-Pointer Simulation and analysis of noise in high-resolution off-axis holograms. Black-Right-Pointing-Pointer Improving signal resolution in the holographically reconstructed phase shift. Black-Right-Pointing-Pointer Comparison of &apos

Optimum aberration coefficients for recording high-resolution off-axis holograms in a Cs-corrected TEM

International Nuclear Information System (INIS)

Linck, Martin

2013-01-01

Amongst the impressive improvements in high-resolution electron microscopy, the Cs-corrector also has significantly enhanced the capabilities of off-axis electron holography. Recently, it has been shown that the signal above noise in the reconstructable phase can be significantly improved by combining holography and hardware aberration correction. Additionally, with a spherical aberration close to zero, the traditional optimum focus for recording high-resolution holograms (“Lichte's defocus”) has become less stringent and both, defocus and spherical aberration, can be selected freely within a certain range. This new degree of freedom can be used to improve the signal resolution in the holographically reconstructed object wave locally, e.g. at the atomic positions. A brute force simulation study for an aberration corrected 200 kV TEM is performed to determine optimum values for defocus and spherical aberration for best possible signal to noise in the reconstructed atomic phase signals. Compared to the optimum aberrations for conventional phase contrast imaging (NCSI), which produce “bright atoms” in the image intensity, the resulting optimum values of defocus and spherical aberration for off-axis holography enable “black atom contrast” in the hologram. However, they can significantly enhance the local signal resolution at the atomic positions. At the same time, the benefits of hardware aberration correction for high-resolution off-axis holography are preserved. It turns out that the optimum is depending on the object and its thickness and therefore not universal. -- Highlights: ► Optimized aberration parameters for high-resolution off-axis holography. ► Simulation and analysis of noise in high-resolution off-axis holograms. ► Improving signal resolution in the holographically reconstructed phase shift. ► Comparison of “black” and “white” atom contrast in off-axis holograms.

Carrier and aberrations removal in interferometric fringe projection profilometry

Science.gov (United States)

Blain, P.; Michel, F.; Renotte, Y.; Habraken, S.

2012-04-01

A profilometer which takes advantage of polarization states splitting technique and monochromatic light projection method as a way to overcome ambient lighting for in-situ measurement is under development [1, 2]. Because of the Savart plate which refracts two out of axis beams, the device suffers from aberrations (mostly coma and astigmatism). These aberrations affect the quality of the sinusoidal fringe pattern. In fringe projection profilometry, the unwrapped phase distribution map contains the sum of the object's shape-related phase and carrier-fringe-related phase. In order to extract the 3D shape of the object, the carrier phase has to be removed [3, 4]. An easy way to remove both the fringe carrier and the aberrations of the optical system is to measure the phases of the test object and to measure the phase of a reference plane with the same set up and to subtract both phase maps. This time consuming technique is suitable for laboratory but not for industry. We propose a method to numerically remove both the fringe carrier and the aberrations. A first reference phase of a calibration plane is evaluated knowing the position of the different elements in the set up and the orientation of the fringes. Then a fitting of the phase map by Zernike polynomials is computed [5]. As the triangulation parameters are known during the calibration, the computation of Zernike coefficients has only to be made once. The wavefront error can be adjusted by a scale factor which depends on the position of the test object.

Research on the Phase Aberration Correction with a Deformable Mirror Controlled by a Genetic Algorithm

International Nuclear Information System (INIS)

Yang, P; Hu, S J; Chen, S Q; Yang, W; Xu, B; Jiang, W H

2006-01-01

In order to improve laser beam quality, a real number encoding genetic algorithm based on adaptive optics technology was presented. This algorithm was applied to control a 19-channel deformable mirror to correct phase aberration in laser beam. It is known that when traditional adaptive optics system is used to correct laser beam wave-front phase aberration, a precondition is to measure the phase aberration information in the laser beam. However, using genetic algorithms, there is no necessary to know the phase aberration information in the laser beam beforehand. The only parameter need to know is the Light intensity behind the pinhole on the focal plane. This parameter was used as the fitness function for the genetic algorithm. Simulation results show that the optimal shape of the 19-channel deformable mirror applied to correct the phase aberration can be ascertained. The peak light intensity was improved by a factor of 21, and the encircled energy strehl ratio was increased to 0.34 from 0.02 as the phase aberration was corrected with this technique

Hyperthermic radiosensitization of synchronous Chinese hamster cells: relationship between lethality and chromosomal aberrations

International Nuclear Information System (INIS)

Dewey, W.C.; Sapareto, S.A.; Betten, D.A.

1978-01-01

Synchronous Chinese hamster cells in vitro were obtained by mitotic selection. The cells were heated at 45.5 0 C for 4 min in mitosis, 11 min in G 1 , or 7 min in S sphase and then x-irradiated immediately thereafter. Colony survival from heat alone was 0.30 to 0.45, and the frequency of chromosomal aberrations induced by heat was 0.00, 0.14, or 0.97 for heat treatments during M, G 1 , or S, respectively. As shown previously, lethality from hyperthermia alone is due to chromosomal aberrations only when the cells are heated during S phase. The log survival (D 0 /sup approximately/ = 80 rad) and aberration frequency curves for cells irradiated during mitosis were linear, and the only effect of hyperthermia was to shift the curves in accord with the effect from heat alone. Thus, hyperthermia did not radiosensitize the mitotic cells. The cells irradiated in G 1 were more resistant (D 0 /sup approximately/ = 100 rad) than those irradiated in mitosis, and the survival and aberration frequency curves both had shoulders. The primary effect of hyperthermia was to greatly reduce the shoulders of the curves and to increase the slopes by about 23%. The cells irradiated in S were the most resistant (D 0 /sup approximately/ = 140 rad), and the survival and aberration frequency curves both had large shoulders. For both end points of lethality and chromosomal aberrations, heat selectively radiosensitized S-phase cells relative to G 1 cells by removing most of the shoulder and increasing the slope by about 45%. For cells treated in G 1 or S, the increase in radiosensitization following hyperthermia can be accounted for by an increase in the frequency of chromosomal aberrations

Action Potential Dynamics in Fine Axons Probed with an Axonally Targeted Optical Voltage Sensor.

Science.gov (United States)

Ma, Yihe; Bayguinov, Peter O; Jackson, Meyer B

2017-01-01

The complex and malleable conduction properties of axons determine how action potentials propagate through extensive axonal arbors to reach synaptic terminals. The excitability of axonal membranes plays a major role in neural circuit function, but because most axons are too thin for conventional electrical recording, their properties remain largely unexplored. To overcome this obstacle, we used a genetically encoded hybrid voltage sensor (hVOS) harboring an axonal targeting motif. Expressing this probe in transgenic mice enabled us to monitor voltage changes optically in two populations of axons in hippocampal slices, the large axons of dentate granule cells (mossy fibers) in the stratum lucidum of the CA3 region and the much finer axons of hilar mossy cells in the inner molecular layer of the dentate gyrus. Action potentials propagated with distinct velocities in each type of axon. Repetitive firing broadened action potentials in both populations, but at an intermediate frequency the degree of broadening differed. Repetitive firing also attenuated action potential amplitudes in both mossy cell and granule cell axons. These results indicate that the features of use-dependent action potential broadening, and possible failure, observed previously in large nerve terminals also appear in much finer unmyelinated axons. Subtle differences in the frequency dependences could influence the propagation of activity through different pathways to excite different populations of neurons. The axonally targeted hVOS probe used here opens up the diverse repertoire of neuronal processes to detailed biophysical study.

Aberrant membranous expression of β-catenin predicts poor prognosis in patients with craniopharyngioma.

Science.gov (United States)

Li, Zongping; Xu, Jianguo; Huang, Siqing; You, Chao

2015-12-01

The objective of this study is to investigate β-catenin expression in craniopharyngioma patients and determine its significance in predicting the prognosis of this disease. Fifty craniopharyngioma patients were enrolled in this study. Expression of β-catenin in tumor specimens collected from these patients was examined through immunostaining. In addition, mutation of exon 3 in the β-catenin gene, CTNNB1, was analyzed using polymerase chain reaction, denaturing high-pressure liquid chromatography, and DNA sequencing. Based on these results, we explored the association between membranous β-catenin expression, clinical and pathologic characteristics, and prognoses in these patients. Of all craniopharyngioma specimens, 31 (62.0%) had preserved membranous β-catenin expression, whereas the remaining 19 specimens (38.0%) displayed aberrant expression. Statistical analysis showed a significant correlation between aberrant membranous β-catenin expression and CTNNB1 exon 3 mutation, as well as between aberrant membranous β-catenin expression and the histopathologic type of craniopharyngioma and type of resection in our patient population. Furthermore, aberrant membranous β-catenin expression was found to be associated with poor patient survival. Results of Kaplan-Meier survival analysis and Cox regression analysis further confirmed this finding. In conclusion, our study demonstrated that aberrant membranous β-catenin expression was significantly correlated with poor survival in patients with craniopharyngioma. This raises the possibility for use of aberrant membranous β-catenin expression as an independent risk factor in predicting the prognosis of this disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Chromatic aberration correction: an enhancement to the calibration of low-cost digital dermoscopes.

Science.gov (United States)

Wighton, Paul; Lee, Tim K; Lui, Harvey; McLean, David; Atkins, M Stella

2011-08-01

We present a method for calibrating low-cost digital dermoscopes that corrects for color and inconsistent lighting and also corrects for chromatic aberration. Chromatic aberration is a form of radial distortion that often occurs in inexpensive digital dermoscopes and creates red and blue halo-like effects on edges. Being radial in nature, distortions due to chromatic aberration are not constant across the image, but rather vary in both magnitude and direction. As a result, distortions are not only visually distracting but could also mislead automated characterization techniques. Two low-cost dermoscopes, based on different consumer-grade cameras, were tested. Color is corrected by imaging a reference and applying singular value decomposition to determine the transformation required to ensure accurate color reproduction. Lighting is corrected by imaging a uniform surface and creating lighting correction maps. Chromatic aberration is corrected using a second-order radial distortion model. Our results for color and lighting calibration are consistent with previously published results, while distortions due to chromatic aberration can be reduced by 42-47% in the two systems considered. The disadvantages of inexpensive dermoscopy can be quickly substantially mitigated with a suitable calibration procedure. © 2011 John Wiley & Sons A/S.

Six years of cytogenetic follow-up of unstable chromosome aberrations in Goiania patients

International Nuclear Information System (INIS)

Ramalho, A.T.; Curado, M.P.; Natarajan, A.T.; Cohen, J.A.

2000-01-01

Following the radiological accident which occurred in the city of Goiania (Brazil), in September of 1987, a cytogenetic follow-up of 16 exposed patients was started, aiming to observe the mean life time of lymphocytes containing dicentric and ring aberrations. The results suggest that for the highly exposed individuals (doses above 1 Gy) the disappearance rate of unstable aberrations follows a two-term exponential function. Up to 470 days after exposure, there is a rapid fall in the aberration frequency. After 470 days, the disappearance rate is very slow. These results may reflect different subpopulations of human lymphocytes, with different life spans. The estimated average half-time of elimination of dicentrics and rings among the highly exposed group (doses above 1 Gy) was 140 days for the initial period after the exposure (up to 470 days). This value is significantly shorter than the usually accepted value of 3 years reported in the literature. For the individuals who had received less than 1 Gy the disappearance of aberrations seems to have occurred in a slower way. Mean disappearance functions of unstable chromosome aberrations were inferred, to be applied in accident situations in which there is a blood sampling delay. (author)

Elimination of aberrations in wide-aperture magnetoelectrostatic plasma lenses

International Nuclear Information System (INIS)

Butenko, V.I.; Ivanov, B.I.

2003-01-01

A computer model is devised for a Morozov plasma lens, in which the magnetic surfaces are equipotential surfaces of the electric field. Results are presented from numerical modeling of the focusing of ions with allowance for their longitudinal, radial, and azimuthal motions. The strengths and spatial distributions of the magnetic and electric fields are optimized. The methods for removing moment, geometric, and chromatic aberrations are analyzed. The effect of a discrete distribution of the potentials on ion focusing is modeled, and the related aberrations are examined. A computer model of an achromatic two-lens system is considered

Questioning the cerebellar doctrine.

Science.gov (United States)

Galliano, Elisa; De Zeeuw, Chris I

2014-01-01

The basic principles of cerebellar function were originally described by Flourens, Cajal, and Marr/Albus/Ito, and they constitute the pillars of what can be considered to be the classic cerebellar doctrine. In their concepts, the main cerebellar function is to control motor behavior, Purkinje cells are the only cortical neuron receiving and integrating inputs from climbing fiber and mossy-parallel fiber pathways, and plastic modification at the parallel fiber synapses onto Purkinje cells constitutes the substrate of motor learning. Yet, because of recent technical advances and new angles of investigation, all pillars of the cerebellar doctrine now face regular re-examination. In this review, after summarizing the classic concepts and recent disputes, we attempt to synthesize an integrated view and propose a revisited version of the cerebellar doctrine. © 2014 Elsevier B.V. All rights reserved.

Adaptive compensation of aberrations in ultrafast 3D microscopy using a deformable mirror

Science.gov (United States)

Sherman, Leah R.; Albert, O.; Schmidt, Christoph F.; Vdovin, Gleb V.; Mourou, Gerard A.; Norris, Theodore B.

2000-05-01

3D imaging using a multiphoton scanning confocal microscope is ultimately limited by aberrations of the system. We describe a system to adaptively compensate the aberrations with a deformable mirror. We have increased the transverse scanning range of the microscope by three with compensation of off-axis aberrations.We have also significantly increased the longitudinal scanning depth with compensation of spherical aberrations from the penetration into the sample. Our correction is based on a genetic algorithm that uses second harmonic or two-photon fluorescence signal excited by femtosecond pulses from the sample as the enhancement parameter. This allows us to globally optimize the wavefront without a wavefront measurement. To improve the speed of the optimization we use Zernike polynomials as the basis for correction. Corrections can be stored in a database for look-up with future samples.

Some aberrant foraminifera from the shelf sediments of central east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A; Almeida, F.

A rich foraminiferal outer shelf assemblage has yielded some aberrant forms in the case of @iUvigerina@@ sp. @iSiphonoperta@@ sp., and @iNodosaria@@ sp. The aberration is (1) in the development of two terminal apertures with parallel necks...

Calibration results using highly aberrated images for aligning the JWST instruments to the telescope

Science.gov (United States)

Smith, Koby Z.; Acton, D. Scott; Gallagher, Ben B.; Knight, J. Scott; Dean, Bruce H.; Jurling, Alden S.; Zielinski, Thomas P.

2016-07-01

The James Webb Space Telescope (JWST) project is an international collaboration led by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, MD. JWST is NASA's flagship observatory that will operate nearly a million miles away from Earth at the L2 Lagrange point. JWST's optical design is a three-mirror anastigmat with four main optical components; 1) the eighteen Primary Mirror Segment Assemblies (PMSA), 2) a single Secondary Mirror Assembly (SMA), 3) an Aft-Optics Subsystem (AOS) consisting of a Tertiary Mirror and Fine Steering Mirror, and 4) an Integrated Science Instrument Module consisting of the various instruments for JWST. JWST's optical system has been designed to accommodate a significant amount of alignment capability and risk with the PMSAs and SMA having rigid body motion available on-orbit just for alignment purposes. However, the Aft-Optics Subsystem (AOS) and Integrated Science Instrument Module (ISIM) are essentially fixed optical subsystems within JWST, and therefore the cryogenic alignment of the AOS to the ISIM is critical to the optical performance and mission success of JWST. In support of this cryogenic alignment of the AOS to ISIM, an array of fiber optic sources, known as the AOS Source Plate Assembly (ASPA), are placed near the intermediate image location of JWST (between the secondary and tertiary mirrors) during thermal vacuum ground-test operations. The AOS produces images of the ASPA fiber optic sources at the JWST focal surface location, where they are captured by the various science instruments. In this manner, the AOS provides an optical yardstick by which the instruments within ISIM can evaluate their relative positions to and the alignment of the AOS to ISIM can be quantified. However, since the ASPA is located at the intermediate image location of the JWST three-mirror anastigmat design, the images of these fiber optic sources produced by the AOS are highly aberrated with approximately 2-3μm RMS wavefront error consisting

Eye aberration analysis with Zernike polynomials

Science.gov (United States)

Molebny, Vasyl V.; Chyzh, Igor H.; Sokurenko, Vyacheslav M.; Pallikaris, Ioannis G.; Naoumidis, Leonidas P.

1998-06-01

New horizons for accurate photorefractive sight correction, afforded by novel flying spot technologies, require adequate measurements of photorefractive properties of an eye. Proposed techniques of eye refraction mapping present results of measurements for finite number of points of eye aperture, requiring to approximate these data by 3D surface. A technique of wave front approximation with Zernike polynomials is described, using optimization of the number of polynomial coefficients. Criterion of optimization is the nearest proximity of the resulted continuous surface to the values calculated for given discrete points. Methodology includes statistical evaluation of minimal root mean square deviation (RMSD) of transverse aberrations, in particular, varying consecutively the values of maximal coefficient indices of Zernike polynomials, recalculating the coefficients, and computing the value of RMSD. Optimization is finished at minimal value of RMSD. Formulas are given for computing ametropia, size of the spot of light on retina, caused by spherical aberration, coma, and astigmatism. Results are illustrated by experimental data, that could be of interest for other applications, where detailed evaluation of eye parameters is needed.

Molecular mechanisms involved in the production of chromosomal aberrations. I

International Nuclear Information System (INIS)

Natarajan, A.T.; Obe, G.

1978-01-01

Chinese hamster ovary cells (CHO) were X-irradiated in G2 stage of the cell cycle and immediately treated, in the presence of inactivated Sendai virus, with Neurospora endonuclease (E.C. 3.1.4.), an enzyme which is specific for cleaving single-stranded DNA. With this treatment, the frequencies of all types of chromosome aberrations increased when compared to X-irradiated controls. These results are interpreted as due to the conversion of some of the X-ray induced single-stranded DNA breaks into double-strand breaks by this enzyme. Similar enhancement due to this enzyme was found following treatment with methyl methanesulfonate (MMS) and bleomycin, but not following UV and mitomycin C. Addition of Micrococcus endonuclease and Neurospora endonuclease to the cells did not alter the frequencies of aberrations induced by UV. The introduction of enzymes with specific DNA-repair function offers possibilities to probe into the molecular events involved in the formation of structural chromosome aberrations induced by different classes of physical and chemical mutagens. (Auth.)

Chromosome aberrations in space-exposed seeds of Allium cepa L

International Nuclear Information System (INIS)

Wang, S.

1994-01-01

Onion (Allium cepa L.) seeds c.v. Patti King were packed in sealed canisters and launched into space orbit about 296 km above earth by the space shuttle Challenger in April 1984. After more than five years exposure to space, the seeds were retrieved by the space shuttle Columbia and returned to earth in January, 1990. Somatic chromosomes at anaphase and telophase stages were analyzed and cells with normal or abnormal chromosome separations were recorded. Space-exposed and control seeds showed an average of 10.9% and 2.8% chromosome aberrations, respectively. Seeds contained in the two exterior layers of the canister had 16.5 to 18.5% chromosome aberration. The results indicated that irradiation in space would be a direct cause for chromosome aberrations in onion seeds. Analysis of seed germination rate and vigor were also determined. The average germination rate for space-exposed and control seeds were 53.3% and 19.8%, respectively. Possible reasons for the results obtained are discussed [it

Chromosome aberrations frequencies in peripheral blood lymphocytes from patients with larynx cancer

International Nuclear Information System (INIS)

Lisowska, H.; Lankoff, A.; Banasik, A.; Padjas, A.; Wieczorek, A.; Kuszewski, T.; Gozdz, A.; Wojcik, A.

2005-01-01

There is data suggesting that the sensitivity to ionising radiation of peripheral blood lymphocytes of cancer patients is higher than in healthy donors. This effect is especially prominent when chromosomal aberrations induced in S/G2 phase of the cell cycle are analysed. The aim of our study was to investigate if the S/G2- aberration frequencies in lymphocytes of patients with larynx cancer were higher than in control individuals. In addition, the multiple fixation regimen was applied in lymphocytes of the cancer patients. The aim of this was to check if the aberration frequencies scored in cells harvested at one time point were representative for a larger fraction of the cell cycle. Peripheral blood of 40 patients was collected before the onset of radiotherapy, cultured and irradiated with Co-60 (2 Gy) after 67 hours of culture time. Irradiation was performed in the Swietokrzyskie Oncology Center. Chromosome specimens were prepared from cells fixed at three time points after irradiation: 5, 7 and 9 hours. Colcemide was always added for 2 hours before harvest. Lymphocytes of 40 healthy donors were cultured and irradiated in the same way like in the case of patients with cancer, however, they were only harvested at one time point (5 hours p.r.). No statistically significant differences in aberration frequencies were observed between lymphocytes harvested at the 3 time points. In both donor groups, individual differences in aberration frequencies were observed. Despite this, the aberration frequencies in lymphocytes of patients were in average higher than in the healthy donors. This suggests, that the radiation sensitivity of lymphocytes of patients with larynx cancer may be a marker of cancer predisposition. More patients must be analysed to confirm this hypothesis. (author)

Prediction for the occurrence of clonal chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Nakano, M.; Kadama, Y.; Ohtaki, K.; Itoh, M.; Awa, A.; Cologne, J.; Nakamura, N.

2003-01-01

Full text: Identical chromosome aberrations among multiple blood lymphocytes in a blood sample (clonal aberrations) are encountered occasionally during cytogenetic examination of radiation-exposed people. Clonal aberrations are found primarily among high-dose exposed people but no systematic surveys were ever conducted. Therefore, the underlying mechanism is unknown. Here we conducted a large-scale screening for detecting clonal aberrations using FISH followed by Q-banding. Examinations of 500 cells from each of 513 A-bomb survivors led us to detect 96 clones. The clonal cell fraction (Cf) varied from 0.6% to 20% among the 500 cells. As the number of clonal event was inversely proportional to Cf, we hypothesized that the progenitor cells vary extensively in the number of offspring that they can produce and relative number of progenitor cells decreases as the increase of treatment, while other genes such as DNA repair proteinsnumber of progenitor cells capable to form clones (Cf >=0.6%) to be 2 (1 to 3) in non-exposed individuals. The number increased to up to 7 among the high-dose exposed survivors. Further, our preliminary results for the origins of 10 clones indicated that both hematopoietic stem cells (HSCs) and mature T cells contributed to the clone formation roughly equally. Thus, the estimated number of 2 in non-exposed individuals is shared as one HSC and one mature T cells. The model could neatly explain the frequency of clones in two reports. Our model predicts that clonal aberrations are rarely found but clonal expansion of T lymphocytes occurs commonly. In fact, clonal expansions of non-aberrant cells are reported using TCR gene rearrangement patterns as a marker. We now understand the rough structure of lymphocyte pool in humans and can predict the probability of detecting a clone if the individual frequency of non-clonal translocations and the number of cells scored are given

Role of DNA polymerase α in chromosomal aberration production by ionizing radiation

International Nuclear Information System (INIS)

Bender, M.A.

1983-01-01

Aphidicolin is a tetracyclic diterpinoid fungal antibiotic which inhibits DNA synthesis in eukaryotic cells by interfering specifically with DNA polymerase α, apparently by binding to and inactivating the DNA-polymerase α complex. We have shown that aphidicolin, like other inhibitors of DNA synthesis, both induces chromosomal aberrations in human peripheral lymphocytes, and, as a post-treatment, interacts synergistically with x rays to produce greatly enhanced aberration yields. The present experiments explore the effects of aphidicolin in human lymphocytes in the post-DNA-synthetic G 2 phase of the cell cycle. These experiments utilized labeling with tritiated thymidine to positively identify cells in the S phase at the time of treatment, and used serial colcemid collections and fixations to determine aberration yields over as much of the G 2 phase as feasible. Because DNA polymerase α is the only DNA synthetic or repair enzyme known to be affected by aphidicolin, we infer that this enzyme is directly involved in the repair of DNA lesions which can result in visible chromosomal aberrations. (DT)

Risk of cancer in an occupationally exposed cohort with increased level of chromosomal aberrations.

Science.gov (United States)

Smerhovsky, Z; Landa, K; Rössner, P; Brabec, M; Zudova, Z; Hola, N; Pokorna, Z; Mareckova, J; Hurychova, D

2001-01-01

We used cytogenetic analysis to carry out a cohort study in which the major objective was to test the association between frequency of chromosomal aberrations and subsequent risk of cancer. In spite of the extensive use of the cytogenetic analysis of human peripheral blood lymphocytes in biomonitoring of exposure to various mutagens and carcinogens on an ecologic level, the long-term effects of an increased frequency of chromosomal aberrations in individuals are still uncertain. Few epidemiologic studies have addressed this issue, and a moderate risk of cancer in individuals with an elevated frequency of chromosomal aberrations has been observed. In the present study, we analyzed data on 8,962 cytogenetic tests and 3,973 subjects. We found a significant and strong association between the frequency of chromosomal aberrations and cancer incidence in a group of miners exposed to radon, where a 1% increase in frequency of chromosomal aberrations was followed by a 64% increase in risk of cancer (p < 0.000). In contrast, the collected data are inadequate for a critical evaluation of the association with exposure to other chemicals. PMID:11171523

Fluorescence in situ hybridisation in chromosome aberration detection in subjects occupationally exposed to ionising radiation

International Nuclear Information System (INIS)

Zeljezic, D.; Garaj-Vrhovac, V.

2005-01-01

For more than two decades, chromosomal aberration analysis has been used to detect structural chromosomal aberrations as sensitive biodosimeters of occupational exposure to ionising radiation. Its use is also recommended by the World Health Organisation. Changes in chromosome structure detected by that method are considered to be early biomarkers of a possible malignant disease. Aberrations detected by the method are unstable and can be found in the lymphocytes of irradiated personnel only within a limited time after exposure. To detect stable chromosomal aberrations, which persist after exposure, multicolour fluorescent in situ hybridisation has to be used. Using DNA probes labelled with different fluorochromes, it dyes each pair of chromosomes with different colour. Due to the dynamic of unstable aberration formation, chromosomal aberration analysis is more suitable in genome damage assessment of recent exposures. On the other hand, fluorescence in situ hybridisation gives the information on chromosome instability caused by long-term occupational exposure to ionising radiation. Considering the high costs of fluorescence in situ hybridisation and the uncertainty of the result, it should be used in biodosimetry only when it is absolutely necessary.(author)

Survival and transmission of symmetrical chromosomal aberrations

International Nuclear Information System (INIS)

Savage, J.R.K.

1979-01-01

The interaction between the lesions to produce chromosomal structural changes may be either asymmetrical (A) or symmetrical (S). In A, one or more acentric fragments are always produced, and there may also be the mechanical separation problems resulting from bridges at anaphase, while S-changes never produce fragment, and pose no mechanical problem in cell division. If A and S events occur with equal frequency, it might be an indication that they are truly the alternative modes of lesion interaction. Unstimulated lymphocytes were irradiated with 2.68 Gy 250 kV X-ray, and metaphases were sampled at 50 h after the stimulation. Preparations were complete diploid cells, and any obvious second division cells were rejected. So far as dermal repair and fibroblast functions are concerned, aberration burden seems to have little consequence from the view-point of the long-term survival in vivo. Large numbers of aberrations (mainly S translocation and terminal deletion) were found in the samples taken up to 60 years after therapy. Skin biopsies were removed 1 day and 6 months after irradiation and cultured. In irradiated cells, reciprocal translocations dominated, followed by terminal deletions, then inversions, while no chromosome-type aberration was seen in the control cells. a) The relative occurrence of A : S changes, b) long-term survival in vivo, c) the possibility of in vivo repair, and d) some unusual features of translocation found in Syrian hamsters are reviewed. The relevance or importance of major S events is clearly dependent upon the cells, the tissues or the organisms in which they occur. (Yamashita, S.)

Amplitude-modulated fiber-ring laser

DEFF Research Database (Denmark)

Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter

2000-01-01

Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...

Seeing atoms with aberration-corrected sub-Angstroem electron microscopy

Energy Technology Data Exchange (ETDEWEB)

O' Keefe, Michael A. [Materials Science Division, Lawrence Berkeley National Laboratory, National Center for Electron Microscopy, 2R0200, 1 Cyclotron Road, Berkeley, CA 94720-8197 (United States)], E-mail: sub-Angstrom@comcast.net

2008-02-15

High-resolution electron microscopy is able to provide atomic-level characterization of many materials in low-index orientations. To achieve the same level of characterization in more complex orientations requires that instrumental resolution be improved to values corresponding to the sub-Angstroem separations of atom positions projected into these orientations. Sub-Angstroem resolution in the high-resolution transmission electron microscope has been achieved in the last few years by software aberration correction, electron holography, and hardware aberration correction; the so-called 'one-Angstroem barrier' has been left behind. Aberration correction of the objective lens currently allows atomic-resolution imaging at the sub-0.8 A level and is advancing towards resolutions in the deep sub-Angstroem range (near 0.5 A). At current resolution levels, images with sub-Rayleigh resolution require calibration in order to pinpoint atom positions correctly. As resolution levels approach the 'sizes' of atoms, the atoms themselves will produce a limit to resolution, no matter how much the instrumental resolution is improved. By arranging imaging conditions suitably, each atom peak in the image can be narrower, so atoms are imaged smaller and may be resolved at finer separations.

Comparative analysis of chromosome aberrations in human lymphocytes induced 'in vitro' by various types of ionizing radiation

International Nuclear Information System (INIS)

Todorov, S.

1975-01-01

A quantitative analysis on various types of chromosome aberrations in human peripheral blood lymphocytes after in vitro whole blood irradiation with 180 kV X-rays, gamma rays from cobalt 60, 50 MeV protons and scission neutrons is carried out. The following aberrations are scored: breaks, total number of aberrations, aberrant cells, chromosome fragments, dicentrics and interstitial deletions. The experimental data obtained are statistically processed applying the method of the least squares and employing four mathematical models: Y = cD 2 , Y = cD, Y = a + bD and Y = a + bD + cD 2 . Statistical analysis showed that after treatment with low LET (linear energy transfer) radiations the most suitable for the description of the kinetic of the two break aberrations, total number of aberrations and breaks in relation to dose is the polynomial second degree model, whereas for one break aberrations and aberrant cells - the linear model. The linear model is equally appropriate for one or two breaks aberrations when it is a matter of high LET radiations. Using the linear component of the polynominal second degree equation a comparative characteristic of the RBE (relative biological effectiveness) for the various radiations types is made. The following mean values for RBE are obtained: 0,86 +- 0,44 for gamma radiation from cobalt 60, 0,98 +- 0,06 for 50 MeV protons and 2,38 +- 0,11 for scission neutrons. (A.B.)

Chromosome aberration analysis in a group of workers who dealt with radioluminious paints

International Nuclear Information System (INIS)

Markovicj, B.; Panov, D.; Joksicj, G.

1988-01-01

By using radiotoxicology tests (H-3 analysis in urine) in a group of workers who dealt with radioluminous paints, the presence of internal contamination was discovered. Moreover, the frequency of chromosome aberrations increased as well. The observation of chromosome aberrations was therefore continued for next 6 and 9 months. Chromosome aberrations still exist even 6 months after taking the subject away from the endangered workplace, but nine months after the incident they mostly disappear from peripheral blood. Biodosimetry investigations show that dose estimates were in the range 0,12 - 0,595 Gy. (author). 3 refs.; 1 tab

Dose Assessment using Chromosome Aberration Analyses in Human Peripheral Blood Lymphocytes

Energy Technology Data Exchange (ETDEWEB)

Ryu, Tae Ho; Kim, Jin-Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

The healthy five donors were recruited to establish the dose-response calibration curve for chromosomal aberrations by ionizing radiation exposure. Our cytogenetic results revealed that the mean frequency of chromosome aberration increased with increasing radiation dose. In this study, dicentric assay and CBMN assay were compared considering the sensitivity and accuracy of dose estimation. Therefore, these chromosome aberration analyses will be the foundation for biological dosimetric analysis with additional research methods such as translocation and PCC assay. The conventional analysis of dicentric chromosomes in HPBL was suggested by Bender and Gooch in 1962. This assay has been for many years, the golden standard and the most specific method for ionizing radiation damage. The dicentric assay technique in HPBL has been shown as the most sensitive biological method and reliable bio-indicator of quantifying the radiation dose. In contrast, the micronucleus assay has advantages over the dicentric assay since it is rapid and requires less specialized expertise, and accordingly it can be applied to monitor a big population. The cytokinesis-block micronucleus (CBMN) assay is a suitable method for micronuceli measurement in cultured human as well as mammalian cells. The aim of our study was to establish the dose response curve of radiation-induced chromosome aberrations in HPBL by analyzing the frequency of dicentrics and micronuclei.

Induction of chromosomal aberrations by neutron capture reactions

International Nuclear Information System (INIS)

Ikushima, Takaji

1993-01-01

Boron neutron capture reaction (B-NCR) has been practiced in the treatment of malignancies of the central nervous system and melanoma using a thermal neutron beam from the KUR. Because of the very large neutron absorption cross-section and high kinetic energy released, gadolinium (Gd-157) has been expected to be an another promising element for neutron capture therapy. The dose-response relationship was determined for the induction of chromosomal aberrations by neutron capture reactions by B-10 and Gd-157 in cultured mammalian cells. The cells were exposed to thermal neutron beam with and without B-10 enriched (97 atom %) boric acid or Gd-DTPA, and chromosome-type aberrations were analysed in the first metaphases following irradiation. The frequency of dicentrics and rings increased linearly with neutron fluence either in the presence or absence of B-10 boric acid, while the yield of chromosomal aberrations induced by Gd-NCR increased in a linear quadratic fashion as a function of dose as in γ-rayed cells. Survival curves for the cells exposed to thermal neutrons showed no shoulder irrespective of the loading of B-10, but Gd-NCR produced the survival curve with a small shoulder. The differential chromosomal response to B-NCR and Gd-NCR might reflect the difference in radiation quality generated from the two types of thermal neutron capture reaction. (J.P.N.)

Aberrant femoral torsion presenting with frog-leg squatting mimicking gluteal muscle contracture.

Science.gov (United States)

Chiang, Chia-Ling; Tsai, Meng-Yuan; Chang, Wei-Ning; Chen, Clement Kuen-Huang

2012-04-01

Patients with frog-leg squatting have restricted internal rotation and adduction of the affected hips during sitting or squatting. In the surgical literature, the cause generally has been presumed to arise from and be pathognomonic for gluteal muscle contracture. However, we have encountered patients with frog-leg squatting but without gluteal muscle contracture. We therefore raised the following questions: What are the imaging features of patients with frog-leg squatting? Do conditions other than gluteal muscle contracture manifest frog-leg squatting? We retrospectively reviewed the MR images of 67 patients presenting with frog-leg squatting from April 1998 to July 2010. There were four females and 63 males; their mean age was 22.2 years (range, 4-50 years). During MRI readout, we observed aberrant axes of some femoral necks and obtained additional CT to measure femoral torsion angles in 59 of the 67 patients. MR images of 27 (40%) patients had signs of gluteal muscle contracture. Twenty-two (33%) patients (40 femora) had aberrant femoral torsion, including diminished anteversion (range, 6°-0°; average, 3.9°) in 11 femora of eight patients and femoral retroversion (range, muscle contracture or aberrant femoral torsion. The observation of aberrant femoral torsion was not anticipated before imaging studies. In addition to gluteal muscle contracture, aberrant femoral torsion can be a cause of frog-leg squatting. Level II, diagnostic study. See the guidelines for Authors for a complete description of levels of evidence.

Seven-year changes in corneal power and aberrations after PRK or LASIK.

Science.gov (United States)

Ivarsen, Anders; Hjortdal, Jesper

2012-09-06

To examine long-term changes in corneal power and aberrations in myopic patients randomized to photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK). Forty-five patients with myopia from -6 to -8 diopters (spherical equivalent refraction) were randomized to PRK (n = 20) or LASIK (n = 25). Patients were examined preoperatively and for up to 7 years after surgery. Measurements included refraction, topography (TMS-1), and ultrasound pachymetry. By 3 years, 16 PRK and 15 LASIK patients were examined and by 7 years, 9 PRK and 7 LASIK subjects were available. Only patients who had not been reoperated and attended the two late controls were included in data analyses. Optical analysis of topographic data was used to calculate corneal power and wavefront aberrations. PRK and LASIK caused a similar reduction in corneal power. During the first year after PRK, corneal power increased, but remained stable from 1 to 7 years. In contrast, corneal power continued to increase from 1 to 7 years after LASIK. Both PRK and LASIK caused an increase in coma-like and spherical aberrations that remained constant for 7 years. No significant changes in other higher-order aberrations were observed. The cornea may not be stable even 7 years after LASIK, as indicated by the continuing increase in corneal power. In contrast, PRK appears stable from 1 year post surgery. Coma-like and spherical aberrations are permanently increased after PRK and LASIK. (ClinicalTrials.gov number, NCT00404105.).

Propagation of highly aberrated laser beams in nonquadratic plasma waveguides

International Nuclear Information System (INIS)

Feit, M.D.; Fleck, J.A. Jr.; Morris, J.R.

1977-01-01

The propagation of a laser beam in a plasma column several meters long with a realistic electron density distribution is examined. The electron density distribution is based on laser-beam heating at z=0, but is otherwise uncoupled to the laser beam. The aberrated nature of the resulting lenslike medium leads to essentially aperiodic beam properties, which contrast with the completely periodic properties of Gaussian beams propagating in quadratic lenslike media. The beam is nonetheless stably trapped. These aberrated-beam properties also help to stabilize the beam against axial variations in refractive index

Disruption of Maternal DNA Repair Increases Sperm-DerivedChromosomal Aberrations

Energy Technology Data Exchange (ETDEWEB)

Marchetti, Francesco; Essers, Jeroun; Kanaar, Roland; Wyrobek,Andrew J.

2007-02-07

The final weeks of male germ cell differentiation occur in aDNA repair-deficient environment and normal development depends on theability of the egg to repair DNA damage in the fertilizing sperm. Geneticdisruption of maternal DNA double-strand break repair pathways in micesignificantly increased the frequency of zygotes with chromosomalstructural aberrations after paternal exposure to ionizing radiation.These findings demonstrate that radiation-induced DNA sperm lesions arerepaired after fertilization by maternal factors and suggest that geneticvariation in maternal DNA repair can modulate the risk of early pregnancylosses and of children with chromosomal aberrations of paternalorigin.

Neuropharmacologic characterization of strychnine seizure potentiation in the inferior olive lesioned rat

International Nuclear Information System (INIS)

Anderson, M.C.

1988-01-01

Cerebellar stimulation is associated with anticonvulsant activity in several animal models. There are two afferent inputs to cerebellar Purkinje cells: (1) parallel fibers, which relay mossy fiber input, from brainstem, spinal cord, cerebral cortex and cerebellum, and (2) climbing fibers, arising from the inferior olive. Both climbing and parallel fibers release excitatory amino acid neurotransmitters, which stimulate Purkinje cells and cause GABA release in the deep cerebellar nuclei. Climbing fibers also exert tonic inhibition over Purkinje cell activity by producing an absolute refractory period following stimulation, rendering Purkinje cells unresponsive to parallel fibers. Climbing fiber deafferentation by bilateral inferior olive lesions produced a specific decrease in threshold for strychnine-seizures in the rat. Inferior olive lesions produced no change in threshold to seizures induced by picrotoxin, bicuculline or pentylenetetrazole. Inferior olive lesions also produced abnormal motor behavior including, myoclonus, backward locomotion and hyperextension, which was significantly aggravated by strychnine, brucine, picrotoxin, bicuculline and pentylenetetrazole. Inferior olive lesions produced a significant increase in quisqualate sensitive [ 3 H]AMPA ((Rs)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid) binding to cerebellar membranes. AMPA is a glutamate analog with high affinity for quisqualate sensitive receptors

Diurnal inhibition of NMDA-EPSCs at rat hippocampal mossy fibre synapses through orexin-2 receptors

Science.gov (United States)

Perin, Martina; Longordo, Fabio; Massonnet, Christine; Welker, Egbert; Lüthi, Anita

2014-01-01

Diurnal release of the orexin neuropeptides orexin-A (Ox-A, hypocretin-1) and orexin-B (Ox-B, hypocretin-2) stabilises arousal, regulates energy homeostasis and contributes to cognition and learning. However, whether cellular correlates of brain plasticity are regulated through orexins, and whether they do so in a time-of-day-dependent manner, has never been assessed. Immunohistochemically we found sparse but widespread innervation of hippocampal subfields through Ox-A- and Ox-B-containing fibres in young adult rats. The actions of Ox-A were studied on NMDA receptor (NMDAR)-mediated excitatory synaptic transmission in acute hippocampal slices prepared around the trough (Zeitgeber time (ZT) 4–8, corresponding to 4–8 h into the resting phase) and peak (ZT 23) of intracerebroventricular orexin levels. At ZT 4–8, exogenous Ox-A (100 nm in bath) inhibited NMDA receptor-mediated excitatory postsynaptic currents (NMDA-EPSCs) at mossy fibre (MF)–CA3 (to 55.6 ± 6.8% of control, P = 0.0003) and at Schaffer collateral–CA1 synapses (70.8 ± 6.3%, P = 0.013), whereas it remained ineffective at non-MF excitatory synapses in CA3. Ox-A actions were mediated postsynaptically and blocked by the orexin-2 receptor (OX2R) antagonist JNJ10397049 (1 μm), but not by orexin-1 receptor inhibition (SB334867, 1 μm) or by adrenergic and cholinergic antagonists. At ZT 23, inhibitory effects of exogenous Ox-A were absent (97.6 ± 2.9%, P = 0.42), but reinstated (87.2 ± 3.3%, P = 0.002) when endogenous orexin signalling was attenuated for 5 h through i.p. injections of almorexant (100 mg kg−1), a dual orexin receptor antagonist. In conclusion, endogenous orexins modulate hippocampal NMDAR function in a time-of-day-dependent manner, suggesting that they may influence cellular plasticity and consequent variations in memory performance across the sleep–wake cycle. PMID:25085886

Photographic simulation of off-axis blurring due to chromatic aberration in spectacle lenses.

Science.gov (United States)

Doroslovački, Pavle; Guyton, David L

2015-02-01

Spectacle lens materials of high refractive index (nd) tend to have high chromatic dispersion (low Abbé number [V]), which may contribute to visual blurring with oblique viewing. A patient who noted off-axis blurring with new high-refractive-index spectacle lenses prompted us to do a photographic simulation of the off-axis aberrations in 3 readily available spectacle lens materials, CR-39 (nd = 1.50), polyurethane (nd = 1.60), and polycarbonate (nd = 1.59). Both chromatic and monochromatic aberrations were found to cause off-axis image degradation. Chromatic aberration was more prominent in the higher-index materials (especially polycarbonate), whereas the lower-index CR-39 had more astigmatism of oblique incidence. It is important to consider off-axis aberrations when a patient complains of otherwise unexplained blurred vision with a new pair of spectacle lenses, especially given the increasing promotion of high-refractive-index materials with high chromatic dispersion. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Biological radiation dose estimation by chromosomal aberrations analysis in human peripheral blood (dose-effect curve)

International Nuclear Information System (INIS)

Al-Achkar, W.

2001-09-01

In order to draw a dose-effect curve, experimentally gamma ray induced chromosomal aberrations in human peripheral lymphocytes from eight healthy people were studied. Samples from 4 males and 4 females were irradiated in tubes with 0.15, 0.25, 0.5, 1, 1.5, 2, 2.5 gray of gamma ray (Co 60 at dose rate 0.3 Gy/min). Irradiated and control samples were incubated in 37 centigrade for 48 hours cell cultures. Cell cultures then were stopped and metaphases spread, Giemsa stained to score the induced chromosomal aberrations. Chromosomal aberrations from 67888 metaphases were scored. Curves from the total number of dicentrics, dicentrics + rings and total numbers of breaks in cell for each individual or for all people were drawn. An increase of all chromosomal aberrations types with the elevation of the doses was observed. The yield of chromosome aberrations is related to the dose used. These curves give a quick useful estimation of the accidentally radiation exposure. (author)

Influence of Different Diets on Development of DMH-Induced Aberrant Crypt Foci and Colon Tumor Incidence in Wistar Rats

DEFF Research Database (Denmark)

Kristiansen, E.; Thorup, I.; Meyer, Otto A.

1995-01-01

The present study was undertaken to investigate certain dietary factors known to affect the development of colon cancer for their ability to modulate aberrant crypt foci (ACI;). Male Wistar rats were initiated with oral noses of dimethylhydrazine dihydrochloride (DMH-2HCl, 20 mg/kg body wt) once...... a week for to or 20 weeks. Throughout the study the animals were fed I) semisynthetic casein-based control diet, 2) control diet with 20% lard, 3) control diet with 20% lard and 20% dietary fiber, or 4) control diet where most of the carbohydrate pool was substituted with sucrose and dextrin....... The composition of the different diets was designed to achieve equivalent intakes of essential nutrients. Animals were killed after 10, 20, and 31 weeks. The study showed a pronounced effect of dietary composition on the development of DMH-induced ACF. The diet high in sucrose and dextrin caused a statistically...

Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Jung-Ah [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Im, Kyong Ok; Park, Si Nae; Kwon, Ji Seok [Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Seon Young [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Oh, Keunhee; Lee, Dong-Sup [Laboratory of Immunology and Cancer Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul (Korea, Republic of); Transplantation Research Institute, Seoul National University College of Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Min Kyung; Kim, Seong Who [Department of Biochemistry and Molecular Biology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jang, Mi; Lee, Gene [Lab of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Oh, Yeon-Mok; Lee, Sang Do [Department of Pulmonary and Critical Care Medicine, Asthma Center and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Dong Soon, E-mail: soonlee@snu.ac.kr [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2015-07-15

Highlights: • We evaluated cytogenetic aberrations of MSC during culture using G-banding and FISH. • We tracked the quantitative changes of each clone among heterogeneity upon passages. • The changes of cytogenetic profile upon passages were similar to cancer stem cell. - Abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during

Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells

International Nuclear Information System (INIS)

Kim, Jung-Ah; Im, Kyong Ok; Park, Si Nae; Kwon, Ji Seok; Kim, Seon Young; Oh, Keunhee; Lee, Dong-Sup; Kim, Min Kyung; Kim, Seong Who; Jang, Mi; Lee, Gene; Oh, Yeon-Mok; Lee, Sang Do; Lee, Dong Soon

2015-01-01

Highlights: • We evaluated cytogenetic aberrations of MSC during culture using G-banding and FISH. • We tracked the quantitative changes of each clone among heterogeneity upon passages. • The changes of cytogenetic profile upon passages were similar to cancer stem cell. - Abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during

Hybrid Fiber Layup and Fiber-Reinforced Polymeric Composites Produced Therefrom

Science.gov (United States)

Barnell, Thomas J. (Inventor); Garrigan, Sean P. (Inventor); Rauscher, Michael D. (Inventor); Dietsch, Benjamin A. (Inventor); Cupp, Gary N. (Inventor)

2018-01-01

Embodiments of a hybrid fiber layup used to form a fiber-reinforced polymeric composite, and a fiber-reinforced polymeric composite produced therefrom are disclosed. The hybrid fiber layup comprises one or more dry fiber strips and one or more prepreg fiber strips arranged side by side within each layer, wherein the prepreg fiber strips comprise fiber material impregnated with polymer resin and the dry fiber strips comprise fiber material without impregnated polymer resin.

Aberrations and adaptive optics in super-resolution microscopy

Science.gov (United States)

Booth, Martin; Andrade, Débora; Burke, Daniel; Patton, Brian; Zurauskas, Mantas

2015-01-01

As one of the most powerful tools in the biological investigation of cellular structures and dynamic processes, fluorescence microscopy has undergone extraordinary developments in the past decades. The advent of super-resolution techniques has enabled fluorescence microscopy – or rather nanoscopy – to achieve nanoscale resolution in living specimens and unravelled the interior of cells with unprecedented detail. The methods employed in this expanding field of microscopy, however, are especially prone to the detrimental effects of optical aberrations. In this review, we discuss how super-resolution microscopy techniques based upon single-molecule switching, stimulated emission depletion and structured illumination each suffer from aberrations in different ways that are dependent upon intrinsic technical aspects. We discuss the use of adaptive optics as an effective means to overcome this problem. PMID:26124194

Deep Tissue Wavefront Estimation for Sensorless Aberration Correction

Directory of Open Access Journals (Sweden)

Ibrahimovic Emina

2015-01-01

Full Text Available The multiple light scattering in biological tissues limits the measurement depth for traditional wavefront sensor. The attenuated ballistic light and the background noise caused by the diffuse light give low signal to noise ratio for wavefront measurement. To overcome this issue, we introduced a wavefront estimation method based on a ray tracing algorithm to overcome this issue. With the knowledge of the refractive index of the medium, the wavefront is estimated by calculating optical path length of rays from the target inside of the samples. This method can provide not only the information of spherical aberration from the refractive-index mismatch between the medium and biological sample but also other aberrations caused by the irregular interface between them. Simulations based on different configurations are demonstrated in this paper.

Coronary artery with aberrant origin malignant right

International Nuclear Information System (INIS)

Ozcan, E.; Bozlar, U.; Demirkol, S.; Saglam, M.

2012-01-01

Full text: Introduction: Congenital anomalies of the coronary arteries is a major cause of sudden death, especially in young patients. Objectives and tasks: In this study we aim to present a young patient with chest pain who had malignant right coronary artery (RCA) with aberrant origin. Materials and methods: 24-year-old man who applied cardiology clinic for chest pain and palpitations especially after exercise, was referred to our clinic for coronary computed tomography (CT) angiography to evaluate coronary artery anomalies. Results: In CT angiography; we detected aberrant RCA with origin of tubularly part of ascendant aorta with a malignant course between aorta and pulmonary artery. Left main coronary artery, left anterior descending and circumflex artery had normal origin and course. Conclusion: Coronary artery with malignant course may cause sudden death especially after exercise. Coronary CT angiography has an important role in diagnosis of congenital coronary artery anomalies, with high resolution multiplanner reformatted images

Correcting for color crosstalk and chromatic aberration in multicolor particle shadow velocimetry

International Nuclear Information System (INIS)

McPhail, M J; Fontaine, A A; Krane, M H; Goss, L; Crafton, J

2015-01-01

Color crosstalk and chromatic aberration can bias estimates of fluid velocity measured by color particle shadow velocimetry (CPSV), using multicolor illumination and a color camera. This article describes corrections to remove these bias errors, and their evaluation. Color crosstalk removal is demonstrated with linear unmixing. It is also shown that chromatic aberrations may be removed using either scale calibration, or by processing an image illuminated by all colors simultaneously. CPSV measurements of a fully developed turbulent pipe flow of glycerin were conducted. Corrected velocity statistics from these measurements were compared to both single-color PSV and LDV measurements and showed excellent agreement to fourth-order, to well into the viscous sublayer. Recommendations for practical assessment and correction of color aberration and color crosstalk are discussed. (paper)

An aberrant vascular channel in the petrous bone: persistent lateral capital vein?

International Nuclear Information System (INIS)

Hermans, Robert; Rensburg, Leon J. van

2009-01-01

An aberrant channel was identified on CT in the petrous bone in four patients presenting with unrelated otological symptoms. These channels occurred unilaterally in each case. In two patients, the channel was seen to run between the sigmoid sinus sulcus and the superior petrosal sinus sulcus; in one of these patients, a vascular structure was identified within this channel on MRI, connecting the sigmoid sinus and the superior petrosal sinus. In the two other patients, an aberrant channel was seen between the superior petrosal sinus sulcus and the posterior genu of the facial nerve canal. There were no symptoms that could be attributed to the presence of these channels. We postulate that these aberrant vascular channels correspond to a persistent embryological vein, the lateral capital vein. (orig.)

An aberrant vascular channel in the petrous bone: persistent lateral capital vein?

Energy Technology Data Exchange (ETDEWEB)

Hermans, Robert [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Rensburg, Leon J. van [University of the Western Cape, Department of Radiology and Diagnostics, Tygerberg (South Africa)

2009-12-15

An aberrant channel was identified on CT in the petrous bone in four patients presenting with unrelated otological symptoms. These channels occurred unilaterally in each case. In two patients, the channel was seen to run between the sigmoid sinus sulcus and the superior petrosal sinus sulcus; in one of these patients, a vascular structure was identified within this channel on MRI, connecting the sigmoid sinus and the superior petrosal sinus. In the two other patients, an aberrant channel was seen between the superior petrosal sinus sulcus and the posterior genu of the facial nerve canal. There were no symptoms that could be attributed to the presence of these channels. We postulate that these aberrant vascular channels correspond to a persistent embryological vein, the lateral capital vein. (orig.)

The Gaussian formula and spherical aberrations of static and relativistic curved mirrors from Fermat's principle

International Nuclear Information System (INIS)

Sutanto, Sylvia H; Tjiang, Paulus C

2011-01-01

The Gaussian formula and spherical aberrations of static and relativistic curved mirrors are analyzed using the optical path length (OPL) and Fermat's principle. The geometrical figures generated by the rotation of conic sections about their symmetry axes are considered for the shapes of the mirrors. By comparing the results in static and relativistic cases, it is shown that the focal lengths and the spherical aberration relations of the relativistic mirrors obey the Lorentz contraction. Further analysis of the spherical aberrations for both static and relativistic cases have resulted in information about the limits for the paraxial approximation, as well as for the minimum speed of the systems to reduce the spherical aberrations

Observation of lens aberrations for high resolution electron microscopy II: Simple expressions for optimal estimates

Energy Technology Data Exchange (ETDEWEB)

Saxton, W. Owen, E-mail: wos1@cam.ac.uk

2015-04-15

This paper lists simple closed-form expressions estimating aberration coefficients (defocus, astigmatism, three-fold astigmatism, coma / misalignment, spherical aberration) on the basis of image shift or diffractogram shape measurements as a function of injected beam tilt. Simple estimators are given for a large number of injected tilt configurations, optimal in the sense of least-squares fitting of all the measurements, and so better than most reported previously. Standard errors are given for most, allowing different approaches to be compared. Special attention is given to the measurement of the spherical aberration, for which several simple procedures are given, and the effect of foreknowledge of this on other aberration estimates is noted. Details and optimal expressions are also given for a new and simple method of analysis, requiring measurements of the diffractogram mirror axis direction only, which are simpler to make than the focus and astigmatism measurements otherwise required. - Highlights: • Optimal estimators for CTEM lens aberrations are more accurate and/or use fewer observations. • Estimators have been found for defocus, astigmatism, three-fold astigmatism, coma and spherical aberration. • Estimators have been found relying on diffractogram shape, image shift and diffractogram orientation only, for a variety of beam tilts. • The standard error for each estimator has been found.

Changes in monkey crystalline lens spherical aberration during simulated accommodation in a lens stretcher.

Science.gov (United States)

Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

2015-02-10

The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4-16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from -6.3 ± 0.7 μm for young lenses to -5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and -2.6 ± 0.5 μm, respectively. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

An aberration corrected photoemission electron microscope at the advanced light source

International Nuclear Information System (INIS)

Feng, J.; MacDowell, A.A.; Duarte, R.; Doran, A.; Forest, E.; Kelez, N.; Marcus, M.; Munson, D.; Padmore, H.; Petermann, K.; Raoux, S.; Robin, D.; Scholl, A.; Schlueter, R.; Schmid, P.; Stohr, J.; Wan, W.; Wei, D.H.; Wu, Y.

2003-01-01

Design of a new aberration corrected Photoemission electron microscope PEEM3 at the Advanced Light Source is outlined. PEEM3 will be installed on an elliptically polarized undulator beamline and will be used for the study of complex materials at high spatial and spectral resolution. The critical components of PEEM3 are the electron mirror aberration corrector and aberration-free magnetic beam separator. The models to calculate the optical properties of the electron mirror are discussed. The goal of the PEEM3 project is to achieve the highest possible transmission of the system at resolutions comparable to our present PEEM2 system (50 nm) and to enable significantly higher resolution, albeit at the sacrifice of intensity. We have left open the possibility to add an energy filter at a later date, if it becomes necessary driven by scientific need to improve the resolution further

Studies on chromosome aberrations in workers occupationally exposed to radiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Hyung; Oh, Hyeon Joo; Shim, Sun Bo; Roh, Hye Won; Lee, Hai Yong [Korea Food and Drug Administration, Seoul (Korea, Republic of); Kang, Soon Ja [Ewha Womens Univ., Seoul (Korea, Republic of)

1998-06-01

Cytogenetic assays for unstable chromosomes were performed on 54 medical radiation workers who are occupationally exposed to radiation and 42 controls. A total of 15,577 metaphase cells were scored. The frequencies of dicentrics and acentric chromosomes on controls were 0.52*10{sup -3} and 0.82*10{sup -2}, respectively. On radiation workers those were 2.28*10{sup -3} and 1.34*10{sup -2}, respectively. Though the frequencies of all types of chromosome aberrations in the workers were higher than those in the controls, the only significant difference was found in the case of dicentrics (P < 0.01). When we considered exposure dose of recent one year, duration of employment and smoking habit in radiation worker, a slight increase was shown in frequency of unstable chromosome aberrations on these workers, but no statistical differences were observed (P > 0.05) except exposure dose of recent one year (P < 0.05). These results could indicate that low level exposure to ionizing radiation can induce unstable chromosome aberrations in blood lymphocytes.

Fiber webs

Science.gov (United States)

Roger M. Rowell; James S. Han; Von L. Byrd

2005-01-01

Wood fibers can be used to produce a wide variety of low-density three-dimensional webs, mats, and fiber-molded products. Short wood fibers blended with long fibers can be formed into flexible fiber mats, which can be made by physical entanglement, nonwoven needling, or thermoplastic fiber melt matrix technologies. The most common types of flexible mats are carded, air...

New type of chromosomal aberrations in microspores of Tradescancia Paludosa in flight experiments on board of space satelites

Energy Technology Data Exchange (ETDEWEB)

Delone, N L; Antipov, V V; Parfenov, G P

1986-01-01

A new type of chromosomal aberrations - complex nonreciprocal translocations accompanied by spherical fragments, is opened. The results of 30 variants of tests are investigated to establish what factor particularly causes new type of chromosomal aberrations. The experiments have been carried out on boards the space satelites: ''Vostok 3, 4, 5, 6'', ''Voskhod'', ''Kosmos 110'', ''Zond 6, 7'', ''Kosmos 368''. All type of aberrations have been recorded. It is supposed that a new type of aberrations depends on the effect of the sum of dynamic factors. At the same time these aberrations are not the background and escape it by separate bright bursts being independent on the effect of take-off, landing and time of an object staying in weightlessness. There is a type of irradiation causing a special type of aberrations.

New type of chromosomal aberrations in microspores of Tradescancia Paludosa in flight experiments on board of space satelites

International Nuclear Information System (INIS)

Delone, N.L.; Antipov, V.V.; Parfenov, G.P.

1986-01-01

A new type of chromosomal aberrations - complex nonreciprocal translocations accompanied by spherical fragments, is opened. The results of 30 variants of tests are investigated to establish what factor particularly causes new type of chromosomal aberrations. The experiments have been carried out on boards the space satelites: ''Vostok 3, 4, 5, 6'', ''Voskhod'', ''Kosmos 110'', ''Zond 6, 7'', ''Kosmos 368''. All type of aberrations have been recorded. It is supposed that a new type of aberrations depends on the effect of the sum of dynamic factors. At the same time these aberrations are not the background and escape it by separate bright bursts being independent on the effect of take-off, landing and time of an object staying in weightlessness. There is a type of irradiation causing a special type of aberrations

Measuring chromatic aberrations in imaging systems using plasmonic nanoparticles.

Science.gov (United States)

Gennaro, Sylvain D; Roschuk, Tyler R; Maier, Stefan A; Oulton, Rupert F

2016-04-01

We demonstrate a method to measure chromatic aberrations of microscope objectives with metallic nanoparticles using white light. Extinction spectra are recorded while scanning a single nanoparticle through a lens's focal plane. We show a direct correlation between the focal wavelength and the longitudinal chromatic focal shift through our analysis of the variations between the scanned extinction spectra at each scan position and the peak extinction over the entire scan. The method has been tested on achromat and apochromat objectives using aluminum disks varying in size from 260-520 nm. Our method is straightforward, robust, low cost, and broadband with a sensitivity suitable for assessing longitudinal chromatic aberrations in high-numerical-aperture apochromatic corrected lenses.

Chromosomal aberrations and micronuclei frequencies in Bulgarian control population

International Nuclear Information System (INIS)

Popova, I.; Hadjidekova, V.; Hristova, R.; Atanasova, P.

2004-01-01

The aim of this investigation is to represent the frequency of spontaneous chromosomal damages in peripheral blood lymphocytes of Bulgarian control population. Material and methods: The investigated group includes persons belonging to both sexes and different ages. Each of them is interviewed of their social and health status. Sixteen persons are examined using the chromosomal aberrations analysis and forty-five with micronucleus test. The frequency of chromosomal aberrations varied between 0 - 2.4 % and the mean value is 1.00 %. The frequency of cells with micronuclei varied between 4.5 - 24.5 % and the mean value 12,9 %. Further work on the investigation of spontaneous frequency of chromosomal damages is in progress. (authors)

Fixational eye movement: a negligible source of dynamic aberration.

Science.gov (United States)

Mecê, Pedro; Jarosz, Jessica; Conan, Jean-Marc; Petit, Cyril; Grieve, Kate; Paques, Michel; Meimon, Serge

2018-02-01

To evaluate the contribution of fixational eye movements to dynamic aberration, 50 healthy eyes were examined with an original custom-built Shack-Hartmann aberrometer, running at a temporal frequency of 236Hz, with 22 lenslets across a 5mm pupil, synchronized with a 236Hz pupil tracker. A comparison of the dynamic behavior of the first 21 Zernike modes (starting from defocus) with and without digital pupil stabilization, on a 3.4s sequence between blinks, showed that the contribution of fixational eye movements to dynamic aberration is negligible. Therefore we highlighted the fact that a pupil tracker coupled to an Adaptive Optics Ophthalmoscope is not essential to achieve diffraction-limited resolution.

Schizotypal perceptual aberrations of time: correlation between score, behavior and brain activity.

Directory of Open Access Journals (Sweden)

Shahar Arzy

Full Text Available A fundamental trait of the human self is its continuum experience of space and time. Perceptual aberrations of this spatial and temporal continuity is a major characteristic of schizophrenia spectrum disturbances--including schizophrenia, schizotypal personality disorder and schizotypy. We have previously found the classical Perceptual Aberration Scale (PAS scores, related to body and space, to be positively correlated with both behavior and temporo-parietal activation in healthy participants performing a task involving self-projection in space. However, not much is known about the relationship between temporal perceptual aberration, behavior and brain activity. To this aim, we composed a temporal Perceptual Aberration Scale (tPAS similar to the traditional PAS. Testing on 170 participants suggested similar performance for PAS and tPAS. We then correlated tPAS and PAS scores to participants' performance and neural activity in a task of self-projection in time. tPAS scores correlated positively with reaction times across task conditions, as did PAS scores. Evoked potential mapping and electrical neuroimaging showed self-projection in time to recruit a network of brain regions at the left anterior temporal cortex, right temporo-parietal junction, and occipito-temporal cortex, and duration of activation in this network positively correlated with tPAS and PAS scores. These data demonstrate that schizotypal perceptual aberrations of both time and space, as reflected by tPAS and PAS scores, are positively correlated with performance and brain activation during self-projection in time in healthy individuals along the schizophrenia spectrum.

Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana

NARCIS (Netherlands)

Ji, X.

2014-01-01

Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana.

I studied numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and

Joint denoising, demosaicing, and chromatic aberration correction for UHD video

Science.gov (United States)

Jovanov, Ljubomir; Philips, Wilfried; Damstra, Klaas Jan; Ellenbroek, Frank

2017-09-01

High-resolution video capture is crucial for numerous applications such as surveillance, security, industrial inspection, medical imaging and digital entertainment. In the last two decades, we are witnessing a dramatic increase of the spatial resolution and the maximal frame rate of video capturing devices. In order to achieve further resolution increase, numerous challenges will be facing us. Due to the reduced size of the pixel, the amount of light also reduces, leading to the increased noise level. Moreover, the reduced pixel size makes the lens imprecisions more pronounced, which especially applies to chromatic aberrations. Even in the case when high quality lenses are used some chromatic aberration artefacts will remain. Next, noise level additionally increases due to the higher frame rates. To reduce the complexity and the price of the camera, one sensor captures all three colors, by relying on Color Filter Arrays. In order to obtain full resolution color image, missing color components have to be interpolated, i.e. demosaicked, which is more challenging than in the case of lower resolution, due to the increased noise and aberrations. In this paper, we propose a new method, which jointly performs chromatic aberration correction, denoising and demosaicking. By jointly performing the reduction of all artefacts, we are reducing the overall complexity of the system and the introduction of new artefacts. In order to reduce possible flicker we also perform temporal video enhancement. We evaluate the proposed method on a number of publicly available UHD sequences and on sequences recorded in our studio.

Robust fiber clustering of cerebral fiber bundles in white matter

Science.gov (United States)

Yao, Xufeng; Wang, Yongxiong; Zhuang, Songlin

2014-11-01

Diffusion tensor imaging fiber tracking (DTI-FT) has been widely accepted in the diagnosis and treatment of brain diseases. During the rendering pipeline of specific fiber tracts, the image noise and low resolution of DTI would lead to false propagations. In this paper, we propose a robust fiber clustering (FC) approach to diminish false fibers from one fiber tract. Our algorithm consists of three steps. Firstly, the optimized fiber assignment continuous tracking (FACT) is implemented to reconstruct one fiber tract; and then each curved fiber in the fiber tract is mapped to a point by kernel principal component analysis (KPCA); finally, the point clouds of fiber tract are clustered by hierarchical clustering which could distinguish false fibers from true fibers in one tract. In our experiment, the corticospinal tract (CST) in one case of human data in vivo was used to validate our method. Our method showed reliable capability in decreasing the false fibers in one tract. In conclusion, our method could effectively optimize the visualization of fiber bundles and would help a lot in the field of fiber evaluation.

Chromosome painting analysis of radiation-induced aberrant cell clones in the mouse

International Nuclear Information System (INIS)

Spruill, M.D.; Nath, J.; Tucker, J.D.

1997-01-01

In a study of the persistence of radiation-induced translocations over the life span of the mouse, we observed a number of clonal cells in peripheral blood lymphocytes. The presence of clones caused the mean frequency of aberrations at various time points to be elevated which interfered with biodosimetry. For this reason, we have corrected our data for the presence of clones. Mice were given an acute dose of 0, 1, 2, 3 or 4 Gy 137 Cs at 8 weeks of age. Aberrations were measured by painting chromosomes 2 and 8 and cells were examined for clones at 3 months and every 3 months thereafter until 21 months. Clones were identified by comparing the color photographic slides of all abnormal cells from each animal. Determination of clonality was made on the basis of similar breakpoint locations or the presence of other identifying characteristics such as unusual aberrations. To correct the frequency of translocations for the presence of clones, each clone, regardless of how many cells it contained, was counted only once. This reflects the original aberration frequency since each clone originated as only one cell. Among mice exposed to 4 Gy, the mean frequencies of aberrant cell clones ranged from 3-29% of the total number of metaphase cells scored with the highest frequency being 1 year post exposure. 32-70% of reciprocal and 19-92% of non-reciprocal translocations were clonal. A dose response relationship for clones was evident until 21 months when the unexposed animals exhibited a mean frequency of aberrant cell clones >10% of the total number of cells scored. Almost 75% of reciprocal and 95% of non-reciprocal translocations in these unexposed control animals were of clonal origin. Correction for clonal expansion greatly reduced the means and their standard errors at most time points where clonal expansion was prevalent. The biodosimetry was much improved suggesting that correction is beneficial in long-term studies

Analysis of chromosome aberration data by hybrid-scale models

International Nuclear Information System (INIS)

Indrawati, Iwiq; Kumazawa, Shigeru

2000-02-01

This paper presents a new methodology for analyzing data of chromosome aberrations, which is useful to understand the characteristics of dose-response relationships and to construct the calibration curves for the biological dosimetry. The hybrid scale of linear and logarithmic scales brings a particular plotting paper, where the normal section paper, two types of semi-log papers and the log-log paper are continuously connected. The hybrid-hybrid plotting paper may contain nine kinds of linear relationships, and these are conveniently called hybrid scale models. One can systematically select the best-fit model among the nine models by among the conditions for a straight line of data points. A biological interpretation is possible with some hybrid-scale models. In this report, the hybrid scale models were applied to separately reported data on chromosome aberrations in human lymphocytes as well as on chromosome breaks in Tradescantia. The results proved that the proposed models fit the data better than the linear-quadratic model, despite the demerit of the increased number of model parameters. We showed that the hybrid-hybrid model (both variables of dose and response using the hybrid scale) provides the best-fit straight lines to be used as the reliable and readable calibration curves of chromosome aberrations. (author)

The C1q complement family of synaptic organizers: not just complementary.

Science.gov (United States)

Yuzaki, Michisuke

2017-08-01

Molecules that regulate formation, differentiation, and maintenance of synapses are called synaptic organizers. Recently, various 'C1q family' proteins have been shown to be released from neurons, and serve as a new class of synaptic organizers. Cbln1 and C1ql1 proteins regulate the formation and maintenance of parallel fiber-Purkinje cell and climbing fiber-Purkinje cell synapses, respectively, in the cerebellum. Cbln1 also modulates the function of postsynaptic delta2 glutamate receptors to regulate synaptic plasticity. C1ql2 and C1ql3, released from mossy fibers, determine the synaptic localization of postsynaptic kainate receptors in the hippocampus. C1ql3 also regulates the formation of synapses between the basolateral amygdala and the prefrontal cortex. These findings indicate the diverse functions of C1q family proteins in various brain regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chromosomal aberrations induced by alpha particles; Aberraciones cromosomicas inducidas por particulas {alpha}

Energy Technology Data Exchange (ETDEWEB)

Guerrero C, C.; Brena V, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: cgc@nuclear.inin.mx

2005-07-01

The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

Modulation transfer function of a fish-eye lens based on the sixth-order wave aberration theory.

Science.gov (United States)

Jia, Han; Lu, Lijun; Cao, Yiqing

2018-01-10

A calculation program of the modulation transfer function (MTF) of a fish-eye lens is developed with the autocorrelation method, in which the sixth-order wave aberration theory of ultra-wide-angle optical systems is used to simulate the wave aberration distribution at the exit pupil of the optical systems. The autocorrelation integral is processed with the Gauss-Legendre integral, and the magnification chromatic aberration is discussed to calculate polychromatic MTF. The MTF calculation results of a given example are then compared with those previously obtained based on the fourth-order wave aberration theory of plane-symmetrical optical systems and with those from the Zemax program. The study shows that MTF based on the sixth-order wave aberration theory has satisfactory calculation accuracy even for a fish-eye lens with a large acceptance aperture. And the impacts of different types of aberrations on the MTF of a fish-eye lens are analyzed. Finally, we apply the self-adaptive and normalized real-coded genetic algorithm and the MTF developed in the paper to optimize the Nikon F/2.8 fish-eye lens; consequently, the optimized system shows better MTF performances than those of the original design.

Some characteristics and its influence factors of chromosome aberrations of germ cells induced by ionizing radiation in mice

International Nuclear Information System (INIS)

Jin Yuke; Cai Lu; Wang Xianli

1995-01-01

The chromosome aberrations of germ cells in mice by low LET ionizing radiation were systematically studied. The study demonstrated that the chromosome aberrations were linear or linearly square correlated with X-ray doses in large doses; that was linear correlated with X-ray doses in low doses. In addition, there were many factors directly influencing chromosome aberrations. The aberrations of the germ cells in males were 4.4 times of that in females. The aberrations in the germ cells were significantly higher after meiosis than before. The aberrations in secondary spermatocytes were 3.6 times of that in spermatogonia and 10 times of that in primary spermatocytes, respectively. In different phases of meiosis, the amount of chromosome aberrations in leptotene was the least, that in diaknesis was the most. The spermatogonic translocation rate receiving a whole body X-irradiation was 1.74 times of that receiving a local testis X-irradiation. The spermatogonic translocation rate of acute X-irradiation was 4.6∼6.3 times of that of chronic γ-irradiation

Chromatic Aberration Correction for Atomic Resolution TEM Imaging from 20 to 80 kV.

Science.gov (United States)

Linck, Martin; Hartel, Peter; Uhlemann, Stephan; Kahl, Frank; Müller, Heiko; Zach, Joachim; Haider, Max; Niestadt, Marcel; Bischoff, Maarten; Biskupek, Johannes; Lee, Zhongbo; Lehnert, Tibor; Börrnert, Felix; Rose, Harald; Kaiser, Ute

2016-08-12

Atomic resolution in transmission electron microscopy of thin and light-atom materials requires a rigorous reduction of the beam energy to reduce knockon damage. However, at the same time, the chromatic aberration deteriorates the resolution of the TEM image dramatically. Within the framework of the SALVE project, we introduce a newly developed C_{c}/C_{s} corrector that is capable of correcting both the chromatic and the spherical aberration in the range of accelerating voltages from 20 to 80 kV. The corrector allows correcting axial aberrations up to fifth order as well as the dominating off-axial aberrations. Over the entire voltage range, optimum phase-contrast imaging conditions for weak signals from light atoms can be adjusted for an optical aperture of at least 55 mrad. The information transfer within this aperture is no longer limited by chromatic aberrations. We demonstrate the performance of the microscope using the examples of 30 kV phase-contrast TEM images of graphene and molybdenum disulfide, showing unprecedented contrast and resolution that matches image calculations.

Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete.

Science.gov (United States)

Song, Weimin; Yin, Jian

2016-08-18

Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored.

Corneal aberrations in keratoconic eyes: influence of pupil size and centering

International Nuclear Information System (INIS)

Comastri, S A; Perez, G D; Martin, G; Bianchetti, A; Perez, L I

2011-01-01

Ocular aberrations vary among subjects and under different conditions and are commonly analyzed expanding the wavefront aberration function in Zernike polynomials. In previous articles, explicit analytical formulas to transform Zernike coefficients of up to 7th order corresponding to an original pupil into those related to a contracted displaced new pupil are obtained. In the present paper these formulas are applied to 20 keratoconic corneas of varying severity. Employing the SN CT1000 topographer, aberrations of the anterior corneal surface for a pupil of semi-diameter 3 mm centered on the keratometric axis are evaluated, the relation between the higher-order root mean square wavefront error and the index KISA% characterizing keratoconus is studied and the size and centering of the ocular photopic natural pupil are determined. Using these data and the transformation formulas, new coefficients associated to the photopic pupil size are computed and their variation when coordinates origin is shifted from the keratometric axis to the ocular pupil centre is analyzed.

A new aberration-corrected, energy-filtered LEEM/PEEM instrument II. Operation and results

International Nuclear Information System (INIS)

Tromp, R.M.; Hannon, J.B.; Wan, W.; Berghaus, A.; Schaff, O.

2013-01-01

In Part I we described a new design for an aberration-corrected Low Energy Electron Microscope (LEEM) and Photo Electron Emission Microscope (PEEM) equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control of the chromatic and spherical aberration coefficients C c and C 3 , as well as the mirror focal length. In this Part II we discuss details of microscope operation, how the microscope is set up in a systematic fashion, and we present typical results. - Highlights: ► The C c and C 3 aberrations of a LEEM/PEEM instrument are corrected with an electrostatic electron mirror. ► The mirror provides independent control over C c , C 3 and focal length in close agreement with theory. ► A detailed alignment procedure for the corrected microscope is given. ► Novel methods to measure C c and C 3 of the objective lens and the mirror are presented. ► We demonstrate a record spatial resolution of 2 nm

Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

Science.gov (United States)

Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

2015-08-04

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

In vivo high-affinity uptake and axonal transport of D-(2,3-/sup 3/H)aspartate in excitatory neurons

Energy Technology Data Exchange (ETDEWEB)

Storm-Mathisen, J.; Wold, J.E. (Oslo Univ. (Norway))

1981-12-28

D-(2,3-/sup 3/H)aspartate ((/sup 3/H)D-Asp) at ..mu..M concentrations in Krebs' solution was infused intracerebrally in rats, mice and hamsters. Neuropil sites in the hippocampal formation, septum and neostriatum, known to receive excitatory nerve inputs with glutamate and aspartate as putative transmitters, showed strong autoradiographic labeling after intraventricular infusions. There was evidence for retrograde axonal transport to pyramidal cell bodies in hippocampus CA3 and neocortex. Infusions into the hilus fasciae dentatae led to anterograde axonal transport of (/sup 3/H)D-Asp in the mossy fibers.

Learning spatial orientation tasks in the radial-maze and structural variation in the hippocampus in inbred mice

Directory of Open Access Journals (Sweden)

Schwegler Herbert

2005-04-01

Full Text Available Abstract In the present paper we review a series of experiments showing that heritable variations in the size of the hippocampal intra- and infrapyramidal mossy fiber (IIPMF terminal fields correlate with performance in spatial, but not non-spatial radial-maze tasks. Experimental manipulation of the size of this projection by means of early postnatal hyperthyroidism produces the effects predicted from the correlations obtained with inbred mouse strains. Although the physiological mechanisms behind these correlations are unknown as yet, several lines of evidence indicate that these correlations are causal.

Automated aberration correction of arbitrary laser modes in high numerical aperture systems

OpenAIRE

Hering, Julian; Waller, Erik H.; Freymann, Georg von

2016-01-01

Controlling the point-spread-function in three-dimensional laser lithography is crucial for fabricating structures with highest definition and resolution. In contrast to microscopy, aberrations have to be physically corrected prior to writing, to create well defined doughnut modes, bottlebeams or multi foci modes. We report on a modified Gerchberg-Saxton algorithm for spatial-light-modulator based automated aberration compensation to optimize arbitrary laser-modes in a high numerical aperture...

New trends and techniques in chromosome aberration analysis

International Nuclear Information System (INIS)

Bender, M.A.

1978-01-01

The following topics are discussed: automation of chromosome analysis; storage of fixed cells from cultures of lymphocytes obtained routinely during periodic employee medical examinations; analysis of banded chromosomes; identification of first division metaphases; sister chromatid exchange; and patterns of aberration induction

Mechanisms of induction of chromosomal aberrations and their detection by fluorescence in situ hybridization

International Nuclear Information System (INIS)

Natarajan, A.T.

2002-01-01

Recently introduced fluorescence in situ hybridization (FISH) technique employing chromosome specific DNA libraries as well as region specific DNA probes (e.g., centromere, telomere) have helped to analyse chromosomal aberrations in great detail and thus have given some new insights into the mechanisms of induction of chromosomal aberrations. The relative proportion of induction of translocations and dicentrics by ionising radiation was studied in human, mice and Chinese hamster cells. Many of the studies point to the differences between the mechanisms of induction of dicentrics and translocations. Preliminary results obtained in our laboratory using arm specific probes for human chromosomes 1 and 3 indicate that the aberrations between the arms appear to be more than expected on a random basis. By employing telomeric probes the frequencies of interstitial deletions were found to be high and similar to the frequencies of dicentrics both in human and mouse lymphocytes. A recent study with human chromosome specific probes clearly shows variation of sensitivity of chromosomes for the induction of exchange aberrations. Radiation response studies with Chinese hamster cells using telomeric probes, suggest that telomeric sequences, especially interstitial ones appear to be an important factor in the origin of both spontaneous and induced chromosomal aberrations

Endobronchial angiofibroma in the aberrant tracheal bronchus presenting as spontaneous pneumomediastinum.

Science.gov (United States)

Kim, Kyung Soo; Moon, Young Kyu; Jeon, Hyun Woo; Park, Chan Beom; Ahn, Myeong Im; Lee, Kyo Young; Park, Jae Kil

2015-07-22

Spontaneous pneumomediastinum is a self-limiting benign disease but abnormal bronchial lesions can be rarely found incidentally, and in selected cases will require surgical resection. A 38-year-old man presented with a spontaneous pneumomediastinum. Chest computed tomography revealed an incidental linear endobronchial tumour in the aberrant tracheal bronchus. The tumour was removed surgically and diagnosed with a rare benign tumour of endobronchial angiofibroma. We report a rare case of endobronchial angiofibroma in the aberrant tracheal bronchus which was detected during the evaluation of a spontaneous pneumomediastinum.

Statistical methods in regression and calibration analysis of chromosome aberration data

International Nuclear Information System (INIS)

Merkle, W.

1983-01-01

The method of iteratively reweighted least squares for the regression analysis of Poisson distributed chromosome aberration data is reviewed in the context of other fit procedures used in the cytogenetic literature. As an application of the resulting regression curves methods for calculating confidence intervals on dose from aberration yield are described and compared, and, for the linear quadratic model a confidence interval is given. Emphasis is placed on the rational interpretation and the limitations of various methods from a statistical point of view. (orig./MG)

Genome wide identification of aberrant alternative splicing events in myotonic dystrophy type 2.

Science.gov (United States)

Perfetti, Alessandra; Greco, Simona; Fasanaro, Pasquale; Bugiardini, Enrico; Cardani, Rosanna; Garcia-Manteiga, Jose M; Manteiga, Jose M Garcia; Riba, Michela; Cittaro, Davide; Stupka, Elia; Meola, Giovanni; Martelli, Fabio

2014-01-01

Myotonic dystrophy type 2 (DM2) is a genetic, autosomal dominant disease due to expansion of tetraplet (CCTG) repetitions in the first intron of the ZNF9/CNBP gene. DM2 is a multisystemic disorder affecting the skeletal muscle, the heart, the eye and the endocrine system. According to the proposed pathological mechanism, the expanded tetraplets have an RNA toxic effect, disrupting the splicing of many mRNAs. Thus, the identification of aberrantly spliced transcripts is instrumental for our understanding of the molecular mechanisms underpinning the disease. The aim of this study was the identification of new aberrant alternative splicing events in DM2 patients. By genome wide analysis of 10 DM2 patients and 10 controls (CTR), we identified 273 alternative spliced exons in 218 genes. While many aberrant splicing events were already identified in the past, most were new. A subset of these events was validated by qPCR assays in 19 DM2 and 15 CTR subjects. To gain insight into the molecular pathways involving the identified aberrantly spliced genes, we performed a bioinformatics analysis with Ingenuity system. This analysis indicated a deregulation of development, cell survival, metabolism, calcium signaling and contractility. In conclusion, our genome wide analysis provided a database of aberrant splicing events in the skeletal muscle of DM2 patients. The affected genes are involved in numerous pathways and networks important for muscle physio-pathology, suggesting that the identified variants may contribute to DM2 pathogenesis.

Chromosome Aberrations in Human Lymphocytes Irradiated with Ionizing Radiation

Energy Technology Data Exchange (ETDEWEB)

Ryu, Tae Ho; Kim, Jin Hong; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

The purpose of the present experiment was to provide data on the dose-dependent production of chromosome aberrations such as dicentrics, centric rings, and excess acentrics. Radiation is one of the more dangerous clastogens in the environment. Ionizing radiation causes chromosome breakages and various cytogenetic aberrations in exposed cells. In an investigation into radiation emergencies, it is important to estimate the dose to exposed persons for several reasons. Physical dosimeters (e. g., film badges) may misrepresent the actual radiation dose and may not be available in a radiological accident or terrorism incident. Biological dosimetry is suitable for estimating the radiation dose during such accidents. The dicentric chromosome assay is very sensitive and a reliable bio-indicator in cases of accidental overexposure.

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

Science.gov (United States)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-01-01

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Cytogenetic biological dosimetry in radiological protection: chromosome aberration analysis in human lymphocyties

International Nuclear Information System (INIS)

Campos, I.M.A. de.

1988-01-01

The effects of ionizing radiation on chromosomes have been know for several decades and dose effect relationships are also fairly well established for several doses and dose rates. Apart from its biological significance, the interpretation of chromosome aberration frequency associated with human exposure to radiation plays an important role in dose assessment, particularly in cases where exposure is though to have occurred but no physical dose monitoring system was present. Based on the cytogenetic data obtained from seven cases of exposure to radiation the aberration frequency have been fitted to the quadratic function Y= αD + βD 2 as the dose response curves from literature. The dose equivalent estimate by frequency of chromosomic aberration found here was compared with 60 Co and 192 Ir already published curves obtained at almost similar dose rate together with some hematological data. (author) [pt

Thulium fiber laser lithotripsy using a muzzle brake fiber tip

Science.gov (United States)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

The Thulium fiber laser (TFL) is being explored as an alternative to Holmium:YAG laser for lithotripsy. TFL beam profile allows coupling of higher power into smaller fibers than multimode Holmium laser beam, without proximal fiber tip degradation. A smaller fiber provides more space in ureteroscope working channel for increased saline irrigation and allows maximum ureteroscope flexion. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback, but increased retropulsion. In this study, a "fiber muzzle brake" was tested for reducing fiber burnback and stone retropulsion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-OD, 360-μm-ID tube with 275-μm thru hole located 250-μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed, ex vivo. Small stones with a mass of 40 +/- 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 +/- 4 s (n=10), without distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers. The muzzle brake fiber tip provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Spherical aberration correction in a scanning transmission electron microscope using a sculpted thin film.

Science.gov (United States)

Shiloh, Roy; Remez, Roei; Lu, Peng-Han; Jin, Lei; Lereah, Yossi; Tavabi, Amir H; Dunin-Borkowski, Rafal E; Arie, Ady

2018-06-01

Nearly eighty years ago, Scherzer showed that rotationally symmetric, charge-free, static electron lenses are limited by an unavoidable, positive spherical aberration. Following a long struggle, a major breakthrough in the spatial resolution of electron microscopes was reached two decades ago by abandoning the first of these conditions, with the successful development of multipole aberration correctors. Here, we use a refractive silicon nitride thin film to tackle the second of Scherzer's constraints and demonstrate an alternative method for correcting spherical aberration in a scanning transmission electron microscope. We reveal features in Si and Cu samples that cannot be resolved in an uncorrected microscope. Our thin film corrector can be implemented as an immediate low cost upgrade to existing electron microscopes without re-engineering of the electron column or complicated operation protocols and can be extended to the correction of additional aberrations. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Combining noncontingent reinforcement and differential reinforcement schedules as treatment for aberrant behavior.

OpenAIRE

Marcus, B A; Vollmer, T R

1996-01-01

Research has shown that noncontingent reinforcement (NCR) can be an effective behavior-reduction procedure when based on a functional analysis. The effects of NCR may be a result of elimination of the contingency between aberrant behavior and reinforcing consequences (extinction) or frequent and free access to reinforcers that may reduce the participant's motivation to engage in aberrant behaviors or mands. If motivation is momentarily reduced, behavior such as mands may not be sensitive to p...

Influence of DMSO on Carbon K ultrasoft X-rays induced chromosome aberrations in V79 Chinese hamster cells

Energy Technology Data Exchange (ETDEWEB)

Natarajan, Adayapalam T., E-mail: natarajan@live.nl [University of Tuscia, Viterbo (Italy); Palitti, Fabrizio [University of Tuscia, Viterbo (Italy); Hill, Mark A. [CRUK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom); MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD (United Kingdom); Stevens, David L. [MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD (United Kingdom); Ahnstroem, Gunnar [Department of Microbiology and Genetic Toxicology, Stockholm University, Stockholm (Sweden)

2010-09-10

Ultrasoft X-rays have been shown to be very efficient in inducing chromosomal aberrations in mammalian cells. The present study was aimed to evaluate the modifying effects of DMSO (a potent scavenger of free radicals) on the frequencies of chromosome aberrations induced by soft X-rays. Confluent held G1 Chinese hamster cells (V79) were irradiated with Carbon K ultrasoft X-rays in the presence and absence of 1 M DMSO and frequencies of chromosome aberrations in the first division cells were determined. DMSO reduced the frequencies of exchange types of aberrations (dicentrics and centric rings) by a factor of 2.1-3.5. The results indicate that free radicals induced by ultrasoft X-rays contribute to a great extent to the induction of chromosome aberrations. The possible implications of these results in interpreting the mechanisms involved in the high efficiency of ultrasoft X-rays in the induction of chromosome aberrations are discussed.

Frequency of chromosomal aberrations in workers occupationally exposed to ionizing radiations

International Nuclear Information System (INIS)

Spasojevic-Tisma, V.; Joksic, G.; Ilic, Z.; Milanovic, S.; Djuric, J.; Tisma, J.; Celeketic, D.; Cuknic, O.; Perisic, J.; Milacic, S.; Cuknic, O.)

2007-01-01

Subjects occupationally exposed to ionizing radiation (external exposition) are examined for chromosomal aberrations in peripheral blood lymphocytes in comparison to a control group. The average annual absorbed dose, measured by TLD dosimeters, for all three groups did not exceed 2mSv. Continuous exposure to small doses of ionizing radiation causes unstable aberrations in lymphocytes. In this research the largest number of found alterations are of acentric fragments and chromosomal breaks type. The highest occupational risk appears to be for subjects working in manufacturing of radio isotope technetium [sr

Studies of chromosomal aberrations in occupationally coal exposed population (coal cutters)

International Nuclear Information System (INIS)

Vijender Reddy, V.; Rudrama Devi, K.

1995-01-01

A detailed study was carried out among the 235 coal mine workers (coal cutters) and 215 unexposed individuals (controls) on cytogenetic effect of coal in peripheral blood lymphocytes. The frequencies of chromosomal aberrations were studied in exposed coal mine workers as well as in the control groups . The confounding factors like smoking drinking and combination of both were taken into account. There was a significant increase in the total number of aberrations among exposed population subjected to different habits like smoking and alcoholism compared to that of the controls. (author). 14 refs., 1 tab

Structural and numerical chromosome aberration inducers in liver micronucleus test in rats with partial hepatectomy.

Science.gov (United States)

Itoh, Satoru; Hattori, Chiharu; Nagata, Mayumi; Sanbuissho, Atsushi

2012-08-30

The liver micronucleus test is an important method to detect pro-mutagens such as active metabolites not reaching bone marrow due to their short lifespan. We have already reported that dosing of the test compound after partial hepatectomy (PH) is essential to detect genotoxicity of numerical chromosome aberration inducers in mice [Mutat. Res. 632 (2007) 89-98]. In naive animals, the proportion of binucleated cells in rats is less than half of that in mice, which suggests a species difference in the response to chromosome aberration inducers. In the present study, we investigated the responses to structural and numerical chromosome aberration inducers in the rat liver micronucleus test. Two structural chromosome aberretion inducers (diethylnitrosamine and 1,2-dimethylhydrazine) and two numerical chromosome aberration inducers (colchicine and carbendazim) were used in the present study. PH was performed a day before or after the dosing of the test compound in 8-week old male F344 rats and hepatocytes were isolated 4 days after the PH. As a result, diethylnitrosamine and 1,2-dimethylhydrazine, structural chromosome aberration inducers, exhibited significant increase in the incidence of micronucleated hepatocyte (MNH) when given either before and after PH. Colchicine and carbendazim, numerical chromosome aberration inducers, did not result in any toxicologically significant increase in MNH frequency when given before PH, while they exhibited MNH induction when given after PH. It is confirmed that dosing after PH is essential in order to detect genotoxicity of numerical chromosome aberration inducers in rats as well as in mice. Regarding the species difference, a different temporal response to colchicine was identified. Colchicine increased the incidence of MNH 4 days after PH in rats, although such induction in mice was observed 8-10 days after PH. Copyright © 2012 Elsevier B.V. All rights reserved.

Wnt/β-catenin signalling pathway mediated aberrant hippocampal neurogenesis in kainic acid-induced epilepsy.

Science.gov (United States)

Qu, Zhengyi; Su, Fang; Qi, Xueting; Sun, Jianbo; Wang, Hongcai; Qiao, Zhenkui; Zhao, Hong; Zhu, Yulan

2017-10-01

Temporal lobe epilepsy is a chronic disorder of nerve system, mainly characterized by hippocampal sclerosis with massive neuronal loss and severe gliosis. Aberrant neurogenesis has been shown in the epileptogenesis process of temporal lobe epilepsy. However, the molecular mechanisms underlying aberrant neurogenesis remain unclear. The roles of Wnt signalling cascade have been well established in neurogenesis during multiple aspects. Here, we used kainic acid-induced rat epilepsy model to investigate whether Wnt/β-catenin signalling pathway is involved in the aberrant neurogenesis in temporal lobe epilepsy. Immunostaining and western blotting results showed that the expression levels of β-catenin, Wnt3a, and cyclin D1, the key regulators in Wnt signalling pathway, were up-regulated during acute epilepsy induced by the injection of kainic acids, indicating that Wnt signalling pathway was activated in kainic acid-induced temporal lobe epilepsy. Moreover, BrdU labelling results showed that blockade of the Wnt signalling by knocking down β-catenin attenuated aberrant neurogenesis induced by kainic acids injection. Altogether, Wnt/β-catenin signalling pathway mediated hippocampal neurogenesis during epilepsy, which might provide new strategies for clinical treatment of temporal lobe epilepsy. Temporal lobe epilepsy is a chronic disorder of nerve system, mainly characterized by hippocampal sclerosis. Aberrant neurogenesis has been shown to involve in the epileptogenesis process of temporal lobe epilepsy. In the present study, we discovered that Wnt3a/β-catenin signalling pathway serves as a link between aberrant neurogenesis and underlying remodelling in the hippocampus, leading to temporal lobe epilepsy, which might provide new strategies for clinical treatment of temporal lobe epilepsy. Copyright © 2017 John Wiley & Sons, Ltd.

The Relevance of Chromosome Aberration Yields for Biological Dosimetry After Low-Level Occupational Irradiation

Energy Technology Data Exchange (ETDEWEB)

Bauchinger, M.; Schmid, E.; Hug, O. [Gesellschaft fuer Strahlenforschung, Institut fuer Biologie, Neuherberg, Federal Republic of Germany (Germany); Strahlenbiologisches Institut der Universitaet Muenchen, Federal Republic of Germany (Germany)

1971-06-15

The usefulness of chromosome analysis for biological dosimetry has been tested in two groups of persons occupationally exposed to radiation: (I) in nurses employed in gynaecological radiology, exposed especially when handling radium inserts; and (II) in nuclear industry workers, all of which were exposed to external gamma irradiation and some of them also to internal radiation after incorporation of various radionuclides. The total dose registered with personal dosimeters ranged in Group 1 from 0.1 to 91.1 rem accumulated over working periods of 0.1 to 13 years, and in Group II from 1.0 to 18.2 rem accumulated over 1 to 9 years. Compared with unexposed controls, both groups exhibit a significant increase of cells with chromosome aberrations as well as larger numbers of breaks per cell. Dicentrics and rings could be observed in some cells, providing good evidence for previous radiation exposure, since these types of aberrations are extremely rare events in unexposed individuals. No correlation between the aberration yields and the film badge values could be demonstrated in Group II. Also, in Group I the fluctuations from individual to individual are rather high. Nevertheless, a positive correlation to the ''dose'' was obtained. Even a sub-group of the nurses that had only been exposed to 20 rem showed significantly more aberrations than control persons. From the results obtained, type and frequency of chromosome aberrations may be considered an indicator of radiation exposure even at the low doses. The reasons for lack of correspondence of chromosome aberration yields and the results of personal monitoring procedures are discussed in detail. (author)

Diminished Dentate Gyrus Filtering of Cortical Input Leads to Enhanced Area Ca3 Excitability after Mild Traumatic Brain Injury.

Science.gov (United States)

Folweiler, Kaitlin A; Samuel, Sandy; Metheny, Hannah E; Cohen, Akiva S

2018-04-06

Mild traumatic brain injury (mTBI) disrupts hippocampal function and can lead to long-lasting episodic memory impairments. The encoding of episodic memories relies on spatial information processing within the hippocampus. As the primary entry point for spatial information into the hippocampus, the dentate gyrus is thought to function as a physiological gate, or filter, of afferent excitation before reaching downstream area Cornu Ammonis (CA3). Although injury has previously been shown to alter dentate gyrus network excitability, it is unknown whether mTBI affects dentate gyrus output to area CA3. In this study, we assessed hippocampal function, specifically the interaction between the dentate gyrus and CA3, using behavioral and electrophysiological techniques in ex vivo brain slices 1 week following mild lateral fluid percussion injury (LFPI). Behaviorally, LFPI mice were found to be impaired in an object-place recognition task, indicating that spatial information processing in the hippocampus is disrupted. Extracellular recordings and voltage-sensitive dye imaging demonstrated that perforant path activation leads to the aberrant spread of excitation from the dentate gyrus into area CA3 along the mossy fiber pathway. These results suggest that after mTBI, the dentate gyrus has a diminished capacity to regulate cortical input into the hippocampus, leading to increased CA3 network excitability. The loss of the dentate filtering efficacy reveals a potential mechanism by which hippocampal-dependent spatial information processing is disrupted, and may contribute to memory dysfunction after mTBI.

The objective lens of the electron microscope with correction of spherical and axial chromatic aberrations.

Science.gov (United States)

Bimurzaev, S B; Aldiyarov, N U; Yakushev, E M

2017-10-01

The paper describes the principle of operation of a relatively simple aberration corrector for the transmission electron microscope objective lens. The electron-optical system of the aberration corrector consists of the two main elements: an electrostatic mirror with rotational symmetry and a magnetic deflector formed by the round-shaped magnetic poles. The corrector operation is demonstrated by calculations on the example of correction of basic aberrations of the well-known objective lens with a bell-shaped distribution of the axial magnetic field. Two of the simplest versions of the corrector are considered: a corrector with a two-electrode electrostatic mirror and a corrector with a three-electrode electrostatic mirror. It is shown that using the two-electrode mirror one can eliminate either spherical or chromatic aberration of the objective lens, without changing the value of its linear magnification. Using a three-electrode mirror, it is possible to eliminate spherical and chromatic aberrations of the objective lens simultaneously, which is especially important in designing electron microscopes with extremely high resolution. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Radiation-induced chromosome aberrations and cell killing in normal human fibroblasts and ataxia telangiectasia fibroblasts

International Nuclear Information System (INIS)

Kawata, T.; Saito, M.; Uno, T.; Ito, H.; Shigematsu, N.

2003-01-01

Full text: When cells are held in a non-dividing state (G0) after irradiation, an enhanced survival can be observed compared to that of immediate plating. A change of survival depending on post irradiation condition is known to be repair of potentially lethal damage (RPLD). The effects of confluent holding recovery (24-h incubation following irradiation) on chromosome aberrations in normal human fibroblasts (AG1522) and ataxia telangiectasia fibroblasts (GM02052C) were examined. A chemical-induced premature chromosome condensation (PCC) technique with fluorescent in situ hybridization (FISH) was applied to study chromosome aberrations in G2 and M-phase. Results from cell survival showed that the capacity for potentially lethal damage repair was normal in AG1522 cells but very little in GM02052C cells. The frequency of chromosome aberrations in AG1522 cells decreased when cells were allowed to repair for 24-h. Especially complex type exchanges were found to decrease markedly at high doses (4Gy and 6Gy). However, the frequency of chromosome aberrations including complex type exchanges showed little decrease in GM02052C cells. Confluent holding can effectively reduce chromosome aberrations, especially complex type exchanges in normal cells

Changes of Corneal Wavefront Aberrations in Dry Eye Patients after Treatment with Artificial Lubricant Drops

Directory of Open Access Journals (Sweden)

Ning Lu

2016-01-01

Full Text Available Purpose. To evaluate the corneal aberration changes in dry eye patients after treatment with artificial eye drops. Methods. Thirty mild to moderate dry eye patients treated with artificial eye drops and twenty comparable dry eye patients were recruited as controls. Anterior corneal aberrations over 3 mm and 5 mm analytical zones including total, 3rd to 5th high order aberrations (HOAs, spherical aberration (SA, and vertical (V-coma and horizontal coma (H-coma obtained from corneal topography data at baseline and 2 weeks after treatment were evaluated. Results. For 3 mm zone, trefoils, V-coma, H-coma terms, and 3rd and 5th HOAs were significantly decreased (p0.05. Conclusions. Treatment with artificial eye drops can effectively improve the corneal optical quality of dry eye patients by ameliorating the HOAs of anterior corneal surface.

Ibrutinib for previously untreated and relapsed or refractory chronic lymphocytic leukaemia with TP53 aberrations

DEFF Research Database (Denmark)

Farooqui, Mohammed Z H; Valdez, Janet; Martyr, Sabrina

2015-01-01

BACKGROUND: Patients with chronic lymphocytic leukaemia (CLL) with TP53 aberrations respond poorly to first-line chemoimmunotherapy, resulting in early relapse and short survival. We investigated the safety and activity of ibrutinib in previously untreated and relapsed or refractory CLL with TP53...... aberrations. METHODS: In this investigator-initiated, single-arm phase 2 study, we enrolled eligible adult patients with active CLL with TP53 aberrations at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Patients received 28-day cycles of ibrutinib 420 mg orally once daily until...... in one (2%) patient. INTERPRETATION: The activity and safety profile of single-agent ibrutinib in CLL with TP53 aberrations is encouraging and supports its consideration as a novel treatment option for patients with this high-risk disease in both first-line and second-line settings. FUNDING: Intramural...

RIGHT-SIDED AORTIC ARCH WITH ABERRANT LEFT SUBCLAVIAN ARTERY AND DUPLICATION OF SUPERIOR VENA CAVA

Directory of Open Access Journals (Sweden)

Parikhita Hazarika

2017-08-01

Full Text Available Right-sided aortic arch is a rare anatomical variant present in about 0.1% of the adult population.1,2 Half of the cases are associated with an aberrant left subclavian artery (0.05%-0.1%. Right-sided aortic arch with aberrant left subclavian artery is less common than left-sided aortic arch with aberrant right subclavian artery (0.5-2.0%.3,4 A rightsided aortic arch is an anatomic variant resulting from persistence of the right fourth aortic arch and involution of the left. It can be associated with an aberrant left subclavian artery arises from Kommerell’s diverticulum. It is usually asymptomatic and diagnosed incidentally during adult age. A 40-year-old male presented with cough and a hump in the back. The patient was evaluated for scoliosis and plain CT thorax was done.

Cellulosic Fibers: Effect of Processing on Fiber Bundle Strength

DEFF Research Database (Denmark)

Thygesen, Anders; Madsen, Bo; Thomsen, Anne Belinda

2011-01-01

A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding, and cotto......A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding...

Artificial neural network for the determination of Hubble Space Telescope aberration from stellar images

Science.gov (United States)

Barrett, Todd K.; Sandler, David G.

1993-01-01

An artificial-neural-network method, first developed for the measurement and control of atmospheric phase distortion, using stellar images, was used to estimate the optical aberration of the Hubble Space Telescope. A total of 26 estimates of distortion was obtained from 23 stellar images acquired at several secondary-mirror axial positions. The results were expressed as coefficients of eight orthogonal Zernike polynomials: focus through third-order spherical. For all modes other than spherical the measured aberration was small. The average spherical aberration of the estimates was -0.299 micron rms, which is in good agreement with predictions obtained when iterative phase-retrieval algorithms were used.

A single-image method of aberration retrieval for imaging systems under partially coherent illumination

International Nuclear Information System (INIS)

Xu, Shuang; Liu, Shiyuan; Zhang, Chuanwei; Wei, Haiqing

2014-01-01

We propose a method for retrieving small lens aberrations in optical imaging systems under partially coherent illumination, which only requires to measure one single defocused image of intensity. By deriving a linear theory of imaging systems, we obtain a generalized formulation of aberration sensitivity in a matrix form, which provides a set of analytic kernels that relate the measured intensity distribution directly to the unknown Zernike coefficients. Sensitivity analysis is performed and test patterns are optimized to ensure well-posedness of the inverse problem. Optical lithography simulations have validated the theoretical derivation and confirmed its simplicity and superior performance in retrieving small lens aberrations. (fast track communication)

Submicroscopic subtelomeric aberrations in Chinese patients with unexplained developmental delay/mental retardation

Directory of Open Access Journals (Sweden)

Wang Liwen

2010-05-01

Full Text Available Abstract Background Subtelomeric imbalance is widely accepted as related to developmental delay/mental retardation (DD/MR. Fine mapping of aberrations in gene-enriched subtelomeric regions provides essential clues for localizing critical regions, and provides a strategy for identifying new candidate genes. To date, no large-scale study has been conducted on subtelomeric aberrations in DD/MR patients in mainland China. Methods This study included 451 Chinese children with moderate to severe clinically unexplained DD/MR. The subtelomere-MLPA (multiplex ligation dependent probe amplification and Affymetrix human SNP array 6.0 were used to determine the subtelomeric copy number variations. The exact size and the breakpoint of each identified aberration were well defined. Results The submicroscopic subtelomeric aberrations were identified in 23 patients, with a detection rate of 5.1%. 16 patients had simple deletions, 2 had simple duplications and 5 with both deletions and duplications. The deletions involved 14 different subtelomeric regions (1p, 2p, 4p, 6p, 7p, 7q, 8p, 9p, 10p, 11q, 14q, 15q, 16p and 22q, and duplications involved 7 subtelomeric regions (3q, 4p, 6q, 7p, 8p, 12p and 22q. Of all the subtelomeric aberrations found in Chinese subjects, the most common was 4p16.3 deletion. The sizes of the deletions varied from 0.6 Mb to 12 Mb, with 5-143 genes inside. Duplicated regions were 0.26 Mb to 11 Mb, with 6-202 genes inside. In this study, four deleted subtelomeric regions and one duplicated region were smaller than any other previously reported, specifically the deletions in 11q25, 8p23.3, 7q36.3, 14q32.33, and the duplication in 22q13. Candidate genes inside each region were proposed. Conclusions Submicroscopic subtelomeric aberrations were detected in 5.1% of Chinese children with clinically unexplained DD/MR. Four deleted subtelomeric regions and one duplicated region found in this study were smaller than any previously reported, which

Design and analysis of beam separator magnets for third generation aberration compensated PEEMs

International Nuclear Information System (INIS)

Wu, Y.K.; Robin, D.S.; Forest, E.; Schlueter, R.; Anders, S.; Feng, J.; Padmore, H.; Wei, D.H.

2004-01-01

A state of the art X-ray photoemission electron microscope (PEEM2) is operational at the Advanced Light Source at a resolution of typically 50 nm for a range of chemical and magnetic surface studies. A new microscope, PEEM3, is under development with an aim of achieving a resolution of 5 nm and more than an order of magnitude increase in transmission at the nominal resolution of PEEM2. The resolution and flux improvement is realized by providing geometric and chromatic aberration compensations in the system using an electron mirror and a beam separator magnet. The nearly aberration-free design of the beam separator is critical to the performance of third generation PEEMs. In this paper, we present the optics design model, optimal operation parameters, analyses of aberration impact, as well as the mechanical alignment tolerance for PEEM3 separator prototypes. In particular, we emphasize the importance of a new semi-analytical approach to design complex charged particle optics using the truncated power series algebra. Because of its ability to compute high-order aberrations, this approach allows systematic and comprehensive analyses of any charged particle optics systems with analytical electric and magnetic fields

Genome-wide identification of significant aberrations in cancer genome.

Science.gov (United States)

Yuan, Xiguo; Yu, Guoqiang; Hou, Xuchu; Shih, Ie-Ming; Clarke, Robert; Zhang, Junying; Hoffman, Eric P; Wang, Roger R; Zhang, Zhen; Wang, Yue

2012-07-27

Somatic Copy Number Alterations (CNAs) in human genomes are present in almost all human cancers. Systematic efforts to characterize such structural variants must effectively distinguish significant consensus events from random background aberrations. Here we introduce Significant Aberration in Cancer (SAIC), a new method for characterizing and assessing the statistical significance of recurrent CNA units. Three main features of SAIC include: (1) exploiting the intrinsic correlation among consecutive probes to assign a score to each CNA unit instead of single probes; (2) performing permutations on CNA units that preserve correlations inherent in the copy number data; and (3) iteratively detecting Significant Copy Number Aberrations (SCAs) and estimating an unbiased null distribution by applying an SCA-exclusive permutation scheme. We test and compare the performance of SAIC against four peer methods (GISTIC, STAC, KC-SMART, CMDS) on a large number of simulation datasets. Experimental results show that SAIC outperforms peer methods in terms of larger area under the Receiver Operating Characteristics curve and increased detection power. We then apply SAIC to analyze structural genomic aberrations acquired in four real cancer genome-wide copy number data sets (ovarian cancer, metastatic prostate cancer, lung adenocarcinoma, glioblastoma). When compared with previously reported results, SAIC successfully identifies most SCAs known to be of biological significance and associated with oncogenes (e.g., KRAS, CCNE1, and MYC) or tumor suppressor genes (e.g., CDKN2A/B). Furthermore, SAIC identifies a number of novel SCAs in these copy number data that encompass tumor related genes and may warrant further studies. Supported by a well-grounded theoretical framework, SAIC has been developed and used to identify SCAs in various cancer copy number data sets, providing useful information to study the landscape of cancer genomes. Open-source and platform-independent SAIC software is