Magnetic suspension motorized spindle-cutting system dynamics analysis and vibration control review

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Xiaoli QIAO

2016-10-01

Full Text Available The performance of high-speed spindle directly determines the development of high-end machine tools. The cutting system's dynamic characteristics and vibration control effect are inseparable with the performance of the spindle,which influence each other, synergistic effect together the cutting efficiency, the surface quality of the workpiece and tool life in machining process. So, the review status on magnetic suspension motorized spindle, magnetic suspension bearing-flexible rotor system dynamics modeling theory and status of active control technology of flexible magnetic suspension motorized spindle rotor vibration are studied, and the problems which present in the magnetic suspension flexible motorized spindle rotor systems are refined, and the development trend of magnetic levitation motorized spindle and the application prospect is forecasted.

The Effect of the Rotor Static Eccentricity on the Electro-Mechanical Coupled Characteristics of the Motorized Spindle

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Wu Zaixin

2016-01-01

Full Text Available High-speed motorized spindle is a multi-variable, non-linear and strong coupling system. The rotor static eccentricity is inevitable because of machining or assembling error. The rotor static eccentricities have an important effect on the electromechanical coupled characteristics of the motorized spindle. In this paper, the electromechanical coupled mathematical model of the motorized spindle was set up. The mathematical model includes mechanical and electrical equation. The mechanical and electrical equation is built up by the variational principle. Furthermore, the inductance parameters without the rotor static eccentricity and the inductance parameters with rotor static eccentricity have been calculated by the winding function method and the high speed motorized spindle was simulated. The result show that the rotor static eccentricity can delay the starting process of the motorized spindle, and at steady state, the rotor circuit currents are still large because of the rotor static eccentricity.

A New Approach to Spindle Radial Error Evaluation Using a Machine Vision System

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Kavitha C.

2017-03-01

Full Text Available The spindle rotational accuracy is one of the important issues in a machine tool which affects the surface topography and dimensional accuracy of a workpiece. This paper presents a machine-vision-based approach to radial error measurement of a lathe spindle using a CMOS camera and a PC-based image processing system. In the present work, a precisely machined cylindrical master is mounted on the spindle as a datum surface and variations of its position are captured using the camera for evaluating runout of the spindle. The Circular Hough Transform (CHT is used to detect variations of the centre position of the master cylinder during spindle rotation at subpixel level from a sequence of images. Radial error values of the spindle are evaluated using the Fourier series analysis of the centre position of the master cylinder calculated with the least squares curve fitting technique. The experiments have been carried out on a lathe at different operating speeds and the spindle radial error estimation results are presented. The proposed method provides a simpler approach to on-machine estimation of the spindle radial error in machine tools.

Human ASPM participates in spindle organisation, spindle orientation and cytokinesis

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Woods C Geoffrey

2010-11-01

Full Text Available Abstract Background Mutations in the Abnormal Spindle Microcephaly related gene (ASPM are the commonest cause of autosomal recessive primary microcephaly (MCPH a disorder characterised by a small brain and associated mental retardation. ASPM encodes a mitotic spindle pole associated protein. It is suggested that the MCPH phenotype arises from proliferation defects in neural progenitor cells (NPC. Results We show that ASPM is a microtubule minus end-associated protein that is recruited in a microtubule-dependent manner to the pericentriolar matrix (PCM at the spindle poles during mitosis. ASPM siRNA reduces ASPM protein at the spindle poles in cultured U2OS cells and severely perturbs a number of aspects of mitosis, including the orientation of the mitotic spindle, the main determinant of developmental asymmetrical cell division. The majority of ASPM depleted mitotic cells fail to complete cytokinesis. In MCPH patient fibroblasts we show that a pathogenic ASPM splice site mutation results in the expression of a novel variant protein lacking a tripeptide motif, a minimal alteration that correlates with a dramatic decrease in ASPM spindle pole localisation. Moreover, expression of dominant-negative ASPM C-terminal fragments cause severe spindle assembly defects and cytokinesis failure in cultured cells. Conclusions These observations indicate that ASPM participates in spindle organisation, spindle positioning and cytokinesis in all dividing cells and that the extreme C-terminus of the protein is required for ASPM localisation and function. Our data supports the hypothesis that the MCPH phenotype caused by ASPM mutation is a consequence of mitotic aberrations during neurogenesis. We propose the effects of ASPM mutation are tolerated in somatic cells but have profound consequences for the symmetrical division of NPCs, due to the unusual morphology of these cells. This antagonises the early expansion of the progenitor pool that underpins cortical

Research on a power management system for thermoelectric generators to drive wireless sensors on a spindle unit.

Science.gov (United States)

Li, Sheng; Yao, Xinhua; Fu, Jianzhong

2014-07-16

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle.

Design of Accelerated Reliability Test for CNC Motorized Spindle Based on Vibration Signal

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Chen Chao

2016-01-01

Full Text Available Motorized spindle is the key functional component of CNC machining centers which is a mechatronics system with long life and high reliability. The reliability test cycle of motorized spindle is too long and infeasible. This paper proposes a new accelerated test for reliability evaluation of motorized spindle. By field reliability test, authors collect and calculate the load data including rotational speed, cutting force and torque. Load spectrum distribution law is analyzed. And authors design a test platform to apply the load spectrum. A new method to define the fuzzy acceleration factor based on the vibration signal is proposed. Then the whole test plan of accelerated reliability test is done.

Adaptive Spindle Balancing Using Magnetically Levitated Bearings

International Nuclear Information System (INIS)

BARNEY, PATRICK S.; LAUFFER, JAMES P.; PETTEYS, REBECCA; REDMOND, JAMES M.; SULLIVAN, WILLIAM N.

1999-01-01

A technological break through for supporting rotating shafts is the active magnetic bearing (AMB). Active magnetic bearings offer some important advantages over conventional ball, roller or journal bearings such as reduced frictional drag, no physical contact in the bearing, no need for lubricants, compatibility with high vacuum and ultra-clean environments, and ability to control shaft position within the bearing. The disadvantages of the AMB system are the increased cost and complexity, reduced bearing stiffness and the need for a controller. Still, there are certain applications, such as high speed machining, biomedical devices, and gyroscopes, where the additional cost of an AMB system can be justified. The inherent actuator capabilities of the AMB offer the potential for active balancing of spindles and micro-shaping capabilities for machine tools, The work presented in this paper concentrates on an AMB test program that utilizes the actuator capability to dynamically balance a spindle. In this study, an unbalanced AMB spindle system was enhanced with an LMS (Least Mean Squares) algorithm combined with an existing PID (proportional, integral, differential) control. This enhanced controller significantly improved the concentricity of an intentionally unbalanced shaft. The study included dynamic system analysis, test validation, control design and simulation, as well as experimental implementation using a digital LMS controller

Nap sleep spindle correlates of intelligence.

Science.gov (United States)

Ujma, Péter P; Bódizs, Róbert; Gombos, Ferenc; Stintzing, Johannes; Konrad, Boris N; Genzel, Lisa; Steiger, Axel; Dresler, Martin

2015-11-26

Sleep spindles are thalamocortical oscillations in non-rapid eye movement (NREM) sleep, that play an important role in sleep-related neuroplasticity and offline information processing. Several studies with full-night sleep recordings have reported a positive association between sleep spindles and fluid intelligence scores, however more recently it has been shown that only few sleep spindle measures correlate with intelligence in females, and none in males. Sleep spindle regulation underlies a circadian rhythm, however the association between spindles and intelligence has not been investigated in daytime nap sleep so far. In a sample of 86 healthy male human subjects, we investigated the correlation between fluid intelligence and sleep spindle parameters in an afternoon nap of 100 minutes. Mean sleep spindle length, amplitude and density were computed for each subject and for each derivation for both slow and fast spindles. A positive association was found between intelligence and slow spindle duration, but not any other sleep spindle parameter. As a positive correlation between intelligence and slow sleep spindle duration in full-night polysomnography has only been reported in females but not males, our results suggest that the association between intelligence and sleep spindles is more complex than previously assumed.

Modeling and characterization of an electromagnetic system for the estimation of Frequency Response Function of spindle

Science.gov (United States)

Tlalolini, David; Ritou, Mathieu; Rabréau, Clément; Le Loch, Sébastien; Furet, Benoit

2018-05-01

The paper presents an electromagnetic system that has been developed to measure the quasi-static and dynamic behavior of machine-tool spindle, at different spindle speeds. This system consists in four Pulse Width Modulation amplifiers and four electromagnets to produce magnetic forces of ± 190 N for the static mode and ± 80 N for the dynamic mode up to 5 kHz. In order to measure the Frequency Response Function (FRF) of spindle, the applied force is required, which is a key issue. A dynamic force model is proposed in order to obtain the load from the measured current in the amplifiers. The model depends on the exciting frequency and on the magnetic characteristics of the system. The predicted force at high speed is validated with a specific experiment and the performance limits of the experimental device are investigated. The FRF obtained with the electromagnetic system is compared to a classical tap test measurement.

Higher efficiency by direct driven spindles with sensorless controlled engine speed in multi-axial machine tools for the timber industry; Verbesserte Energieeffizienz durch direktangetriebene winkelgeberlose drehzahlgeregelte Spindeln bei Mehrachsbohrkoepfen fuer die holzverarbeitende Industrie

Energy Technology Data Exchange (ETDEWEB)

Teisch, Arthur; Obernolte, Urs; Borcherding, Holger [Hochschule Ostwestfalen Lippe, Lemgo (Germany)

2009-07-01

The multi-axial machine tools work mainly with spindles, who are powered by a central motor with a gearbox. These drives have a relative little power efficiency. Due to the progress of the magnetic material it was possible to change the central motor with gear box by small direct driven spindles. Cause of the very high efficiency of the permanentmagnet synchronous machine (PMSM), it is the best option for the new application. With the option of the sensorless control of the rotor speed the costs for an encoder are saved too. With the good efficiency of the PMSM the overall degree of efficiency could be raised by about 70%. Because of the reduced investment, service and energy costs the new systems are more economical to operate. (orig.)

Parameter Estimation of the Thermal Network Model of a Machine Tool Spindle by Self-made Bluetooth Temperature Sensor Module

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Yuan-Chieh Lo

2018-02-01

Full Text Available Thermal characteristic analysis is essential for machine tool spindles because sudden failures may occur due to unexpected thermal issue. This article presents a lumped-parameter Thermal Network Model (TNM and its parameter estimation scheme, including hardware and software, in order to characterize both the steady-state and transient thermal behavior of machine tool spindles. For the hardware, the authors develop a Bluetooth Temperature Sensor Module (BTSM which accompanying with three types of temperature-sensing probes (magnetic, screw, and probe. Its specification, through experimental test, achieves to the precision ±(0.1 + 0.0029|t| °C, resolution 0.00489 °C, power consumption 7 mW, and size Ø40 mm × 27 mm. For the software, the heat transfer characteristics of the machine tool spindle correlative to rotating speed are derived based on the theory of heat transfer and empirical formula. The predictive TNM of spindles was developed by grey-box estimation and experimental results. Even under such complicated operating conditions as various speeds and different initial conditions, the experiments validate that the present modeling methodology provides a robust and reliable tool for the temperature prediction with normalized mean square error of 99.5% agreement, and the present approach is transferable to the other spindles with a similar structure. For realizing the edge computing in smart manufacturing, a reduced-order TNM is constructed by Model Order Reduction (MOR technique and implemented into the real-time embedded system.

The Effects of the Rope Jump Training Program in Physical Education Lessons on Strength, Speed and VO[subscript 2] Max in Children

Science.gov (United States)

Eler, Nebahat; Acar, Hakan

2018-01-01

The aim of this study is to examine the effects of rope-jump training program in physical education lessons on strength, speed and VO[subscript 2] max in 10-12 year old boys. 240 male students; rope-jump group (n = 120) and control group (n = 120) participated in the study. Rope-Jump group continued 10 weeks of regular physical education and sport…

Mechanical design principles of a mitotic spindle.

Science.gov (United States)

Ward, Jonathan J; Roque, Hélio; Antony, Claude; Nédélec, François

2014-12-18

An organised spindle is crucial to the fidelity of chromosome segregation, but the relationship between spindle structure and function is not well understood in any cell type. The anaphase B spindle in fission yeast has a slender morphology and must elongate against compressive forces. This 'pushing' mode of chromosome transport renders the spindle susceptible to breakage, as observed in cells with a variety of defects. Here we perform electron tomographic analyses of the spindle, which suggest that it organises a limited supply of structural components to increase its compressive strength. Structural integrity is maintained throughout the spindle's fourfold elongation by organising microtubules into a rigid transverse array, preserving correct microtubule number and dynamically rescaling microtubule length.

The Spindle Cell Neoplasms of the Oral Cavity.

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Shamim, Thorakkal

2015-01-01

Spindle cell neoplasms are defined as neoplasms that consist of spindle-shaped cells in the histopathology. Spindle cell neoplasms can affect the oral cavity. In the oral cavity, the origin of the spindle cell neoplasms may be traced to epithelial, mesenchymal and odontogenic components. This article aims to review the spindle cell neoplasms of the oral cavity with emphasis on histopathology.

Autodesk 3ds Max 2012 Essentials

CERN Document Server

Derakhshani, Randi L

2011-01-01

Get a jump-start on Autodesk 3ds Max 2012 essentials-with the Essentials! The new Essentials books from Sybex are beautiful, task-based, full-color Autodesk Official Training Guides that help you get up to speed on Autodesk topics quickly and easily. Autodesk 3ds Max 2012 Essentials thoroughly covers the fundamentals of this popular 3D animation effects, and visualization software, teaching you what you need to become quickly productive. By following the book's clear explanations, practical tutorials, and step-by-step exercises, you'll cover all the bases. Topics include modeling, animation,

Design and application on experimental platform for high-speed bearing with grease lubrication

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He Qiang

2015-12-01

Full Text Available The experimental platform for high-speed grease is an important tool for research and development of high-speed motorized spindle with grease lubrication. In this article, the experimental platform for high-speed grease is designed and manufactured which consists of the drive system, the test portion, the loading system, the lubrication system, the control system, and so on. In the meantime, the high-speed angular contact ceramic ball bearings B7005C/HQ1P4 as the research object are tested and contrasted in the grease lubrication and oil mist lubrication. The experimental platform performance is validated by contrast experiment, and the high-speed lubricated bearing performance is also studied especially in the relationship among the rotating speed,load and temperature rise. The results show that the experimental platform works steadily, accurate, and reliable in the experimental testing. And the grease lubrication ceramic ball bearings B7005C/HQ1P4 can be used in high-speed motorized spindle in the circular water cooling conditions when the rotating speed is lower than 40,000 r/min or the DN value (the value of the bearing diameter times the rotating speed is lower than the 1.44 × 106 mm r/min. Grease lubrication instead of oil mist lubrication under high-speed rotating will simplify the structure design of the high-speed motorized spindle and reduce the pollution to the environment.

TECHNICAL NOTE: High-speed grinding using thin abrasive disks for microcomponents

Science.gov (United States)

Yeo, S. H.; Balon, S. A. P.

2002-01-01

This paper introduces the development of a high-speed grinding device for cylindrical grinding of microcomponents made of hard and brittle materials. The study made use of an ultraprecision diamond turning machine tool as a basic platform. The novelty of the device is based on the high-speed air bearing spindle with a thin grinding wheel, similar to the dicing technology for silicon wafer fabrication. The spindle attachment is inclined at an angle to the main spindle which holds the precision fixture mechanism via the vacuum chuck. Experiments have been conducted to verify the design and implementation of the grinding methodology. A feature size as small as 31 μm in diameter and average surface roughness of 98 nm were obtained in the experimental work. It is found that the work done is capable of manufacturing miniature components, such as microcylindrical stepped shafts.

Measuring mitotic spindle dynamics in budding yeast

Science.gov (United States)

Plumb, Kemp

In order to carry out its life cycle and produce viable progeny through cell division, a cell must successfully coordinate and execute a number of complex processes with high fidelity, in an environment dominated by thermal noise. One important example of such a process is the assembly and positioning of the mitotic spindle prior to chromosome segregation. The mitotic spindle is a modular structure composed of two spindle pole bodies, separated in space and spanned by filamentous proteins called microtubules, along which the genetic material of the cell is held. The spindle is responsible for alignment and subsequent segregation of chromosomes into two equal parts; proper spindle positioning and timing ensure that genetic material is appropriately divided amongst mother and daughter cells. In this thesis, I describe fluorescence confocal microscopy and automated image analysis algorithms, which I have used to observe and analyze the real space dynamics of the mitotic spindle in budding yeast. The software can locate structures in three spatial dimensions and track their movement in time. By selecting fluorescent proteins which specifically label the spindle poles and cell periphery, mitotic spindle dynamics have been measured in a coordinate system relevant to the cell division. I describe how I have characterised the accuracy and precision of the algorithms by simulating fluorescence data for both spindle poles and the budding yeast cell surface. In this thesis I also describe the construction of a microfluidic apparatus that allows for the measurement of long time-scale dynamics of individual cells and the development of a cell population. The tools developed in this thesis work will facilitate in-depth quantitative analysis of the non-equilibrium processes in living cells.

A defect-driven diagnostic method for machine tool spindles.

Science.gov (United States)

Vogl, Gregory W; Donmez, M Alkan

2015-01-01

Simple vibration-based metrics are, in many cases, insufficient to diagnose machine tool spindle condition. These metrics couple defect-based motion with spindle dynamics; diagnostics should be defect-driven. A new method and spindle condition estimation device (SCED) were developed to acquire data and to separate system dynamics from defect geometry. Based on this method, a spindle condition metric relying only on defect geometry is proposed. Application of the SCED on various milling and turning spindles shows that the new approach is robust for diagnosing the machine tool spindle condition.

Measuring and modeling polymer concentration profiles near spindle boundaries argues that spindle microtubules regulate their own nucleation

Science.gov (United States)

Kaye, Bryan; Stiehl, Olivia; Foster, Peter J.; Shelley, Michael J.; Needleman, Daniel J.; Fürthauer, Sebastian

2018-05-01

Spindles are self-organized microtubule-based structures that segregate chromosomes during cell division. The mass of the spindle is controlled by the balance between microtubule turnover and nucleation. The mechanisms that control the spatial regulation of microtubule nucleation remain poorly understood. While previous work found that microtubule nucleators bind to pre-existing microtubules in the spindle, it is still unclear whether this binding regulates the activity of those nucleators. Here we use a combination of experiments and mathematical modeling to investigate this issue. We measured the concentration of microtubules and soluble tubulin in and around the spindle. We found a very sharp decay in the concentration of microtubules at the spindle interface. This is inconsistent with a model in which the activity of nucleators is independent of their association with microtubules but consistent with a model in which microtubule nucleators are only active when bound to pre-existing microtubules. This argues that the activity of microtubule nucleators is greatly enhanced when bound to pre-existing microtubules. Thus, microtubule nucleators are both localized and activated by the microtubules they generate.

Applications of a saving method with max-min ant system to a vehicle routing problem with time windows and speed limits

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Suphan Sodsoon

2014-06-01

Full Text Available This study aims to solve a Vehicle Routing Problem with Time Windows and Speed Limits (VRPTWSL, which has received considerable attention in recent years. The vehicle routing problem with time windows is an extension of the well-known Vehicle Routing Problem (VRP and involves a fleet of vehicles set of from a depot to serve a number of customers at different geographic locations with various demands within specific time and speed limits before returning to the depot eventually. To solve the problem, an efficient Saving Method-Max Min Ant System (Saving-MMAS with Local Search algorithm is applied. Using minimization of the total transportation costs as the objective of the extension VRPTWSL, a mathematic model is constructed. Finally, the Saving-MMAS algorithms indicated the good quality of the method in this problem.

Analytical modeling for thermal errors of motorized spindle unit

OpenAIRE

Liu, Teng; Gao, Weiguo; Zhang, Dawei; Zhang, Yifan; Chang, Wenfen; Liang, Cunman; Tian, Yanling

2017-01-01

Modeling method investigation about spindle thermal errors is significant for spindle thermal optimization in design phase. To accurately analyze the thermal errors of motorized spindle unit, this paper assumes approximately that 1) spindle linear thermal error on axial direction is ascribed to shaft thermal elongation for its heat transfer from bearings, and 2) spindle linear thermal errors on radial directions and angular thermal errors are attributed to thermal variations of bearing relati...

Inscuteable Regulates the Pins-Mud Spindle Orientation Pathway

Science.gov (United States)

Mauser, Jonathon F.; Prehoda, Kenneth E.

2012-01-01

During asymmetric cell division, alignment of the mitotic spindle with the cell polarity axis ensures that the cleavage furrow separates fate determinants into distinct daughter cells. The protein Inscuteable (Insc) is thought to link cell polarity and spindle positioning in diverse systems by binding the polarity protein Bazooka (Baz; aka Par-3) and the spindle orienting protein Partner of Inscuteable (Pins; mPins or LGN in mammals). Here we investigate the mechanism of spindle orientation by the Insc-Pins complex. Previously, we defined two Pins spindle orientation pathways: a complex with Mushroom body defect (Mud; NuMA in mammals) is required for full activity, whereas binding to Discs large (Dlg) is sufficient for partial activity. In the current study, we have examined the role of Inscuteable in mediating downstream Pins-mediated spindle orientation pathways. We find that the Insc-Pins complex requires Gαi for partial activity and that the complex specifically recruits Dlg but not Mud. In vitro competition experiments revealed that Insc and Mud compete for binding to the Pins TPR motifs, while Dlg can form a ternary complex with Insc-Pins. Our results suggest that Insc does not passively couple polarity and spindle orientation but preferentially inhibits the Mud pathway, while allowing the Dlg pathway to remain active. Insc-regulated complex assembly may ensure that the spindle is attached to the cortex (via Dlg) before activation of spindle pulling forces by Dynein/Dynactin (via Mud). PMID:22253744

The Physics of the Metaphase Spindle.

Science.gov (United States)

Oriola, David; Needleman, Daniel J; Brugués, Jan

2018-05-20

The assembly of the mitotic spindle and the subsequent segregation of sister chromatids are based on the self-organized action of microtubule filaments, motor proteins, and other microtubule-associated proteins, which constitute the fundamental force-generating elements in the system. Many of the components in the spindle have been identified, but until recently it remained unclear how their collective behaviors resulted in such a robust bipolar structure. Here, we review the current understanding of the physics of the metaphase spindle that is only now starting to emerge.

WiMAX security and quality of service an end-to-end perspective

CERN Document Server

Tang, Seok-Yee; Sharif, Hamid

2010-01-01

WiMAX is the first standard technology to deliver true broadband mobility at speeds that enable powerful multimedia applications such as Voice over Internet Protocol (VoIP), online gaming, mobile TV, and personalized infotainment. WiMAX Security and Quality of Service, focuses on the interdisciplinary subject of advanced Security and Quality of Service (QoS) in WiMAX wireless telecommunication systems including its models, standards, implementations, and applications. Split into 4 parts, Part A of the book is an end-to-end overview of the WiMAX architecture, protocol, and system requirements.

Mitotic spindle proteomics in Chinese hamster ovary cells.

Directory of Open Access Journals (Sweden)

Mary Kate Bonner

Full Text Available Mitosis is a fundamental process in the development of all organisms. The mitotic spindle guides the cell through mitosis as it mediates the segregation of chromosomes, the orientation of the cleavage furrow, and the progression of cell division. Birth defects and tissue-specific cancers often result from abnormalities in mitotic events. Here, we report a proteomic study of the mitotic spindle from Chinese Hamster Ovary (CHO cells. Four different isolations of metaphase spindles were subjected to Multi-dimensional Protein Identification Technology (MudPIT analysis and tandem mass spectrometry. We identified 1155 proteins and used Gene Ontology (GO analysis to categorize proteins into cellular component groups. We then compared our data to the previously published CHO midbody proteome and identified proteins that are unique to the CHO spindle. Our data represent the first mitotic spindle proteome in CHO cells, which augments the list of mitotic spindle components from mammalian cells.

Sleep spindles and intelligence: evidence for a sexual dimorphism.

Science.gov (United States)

Ujma, Péter P; Konrad, Boris Nikolai; Genzel, Lisa; Bleifuss, Annabell; Simor, Péter; Pótári, Adrián; Körmendi, János; Gombos, Ferenc; Steiger, Axel; Bódizs, Róbert; Dresler, Martin

2014-12-03

Sleep spindles are thalamocortical oscillations in nonrapid eye movement sleep, which play an important role in sleep-related neuroplasticity and offline information processing. Sleep spindle features are stable within and vary between individuals, with, for example, females having a higher number of spindles and higher spindle density than males. Sleep spindles have been associated with learning potential and intelligence; however, the details of this relationship have not been fully clarified yet. In a sample of 160 adult human subjects with a broad IQ range, we investigated the relationship between sleep spindle parameters and intelligence. In females, we found a positive age-corrected association between intelligence and fast sleep spindle amplitude in central and frontal derivations and a positive association between intelligence and slow sleep spindle duration in all except one derivation. In males, a negative association between intelligence and fast spindle density in posterior regions was found. Effects were continuous over the entire IQ range. Our results demonstrate that, although there is an association between sleep spindle parameters and intellectual performance, these effects are more modest than previously reported and mainly present in females. This supports the view that intelligence does not rely on a single neural framework, and stronger neural connectivity manifesting in increased thalamocortical oscillations in sleep is one particular mechanism typical for females but not males. Copyright © 2014 the authors 0270-6474/14/3416358-11$15.00/0.

WiMax taking wireless to the max

CERN Document Server

Pareek, Deepak

2006-01-01

With market value expected to reach 5 billion by 2007 and the endorsement of some of the biggest names in telecommunications, World Interoperability for Microwave Access (WiMAX) is poised to change the broadband wireless landscape. But how much of WiMAX's touted potential is merely hype? Now that several pre-WiMAX networks have been deployed, what are the operators saying about QoS and ROI? How and when will device manufacturers integrate WiMAX into their products? What is the business case for using WiMAX rather than any number of other established wireless alternatives?WiMAX: Taking Wireless

Finite Element Analysis of Flexural Vibrations in Hard Disk Drive Spindle Systems

Science.gov (United States)

LIM, SEUNGCHUL

2000-06-01

This paper is concerned with the flexural vibration analysis of the hard disk drive (HDD) spindle system by means of the finite element method. In contrast to previous research, every system component is here analytically modelled taking into account its structural flexibility and also the centrifugal effect particularly on the disk. To prove the effectiveness and accuracy of the formulated models, commercial HDD systems with two and three identical disks are selected as examples. Then their major natural modes are computed with only a small number of element meshes as the shaft rotational speed is varied, and subsequently compared with the existing numerical results obtained using other methods and newly acquired experimental ones. Based on such a series of studies, the proposed method can be concluded as a very promising tool for the design of HDDs and various other high-performance computer disk drives such as floppy disk drives, CD ROM drives, and their variations having spindle mechanisms similar to those of HDDs.

Akap350 Recruits Eb1 to The Spindle Poles, Ensuring Proper Spindle Orientation and Lumen Formation in 3d Epithelial Cell Cultures.

Science.gov (United States)

Almada, Evangelina; Tonucci, Facundo M; Hidalgo, Florencia; Ferretti, Anabela; Ibarra, Solange; Pariani, Alejandro; Vena, Rodrigo; Favre, Cristián; Girardini, Javier; Kierbel, Arlinet; Larocca, M Cecilia

2017-11-02

The organization of epithelial cells to form hollow organs with a single lumen requires the accurate three-dimensional arrangement of cell divisions. Mitotic spindle orientation is defined by signaling pathways that provide molecular links between specific spots at the cell cortex and astral microtubules, which have not been fully elucidated. AKAP350 is a centrosomal/Golgi scaffold protein, implicated in the regulation of microtubule dynamics. Using 3D epithelial cell cultures, we found that cells with decreased AKAP350 expression (AKAP350KD) formed polarized cysts with abnormal lumen morphology. Analysis of mitotic cells in AKAP350KD cysts indicated defective spindle alignment. We established that AKAP350 interacts with EB1, a microtubule associated protein that regulates spindle orientation, at the spindle poles. Decrease of AKAP350 expression lead to a significant reduction of EB1 levels at spindle poles and astral microtubules. Conversely, overexpression of EB1 rescued the defective spindle orientation induced by deficient AKAP350 expression. The specific delocalization of the AKAP350/EB1complex from the centrosome decreased EB1 levels at astral microtubules and lead to the formation of 3D-organotypic structures which resembled AKAP350KD cysts. We conclude that AKAP350 recruits EB1 to the spindle poles, ensuring EB1 presence at astral microtubules and proper spindle orientation during epithelial morphogenesis.

Fabrication and Testing of High-Speed-Single-Rotor and Compound-Rotor Systems

Science.gov (United States)

2016-05-04

laser engraved scales on the base and table and a 1/4" Jacobs drill chuck and key. 7.2 Specifications Max clearance, table to spindle 9.00" (229 mm...This flow control valve is rated for a peak pressure of 315 bar and a maximum flow rate of 330 l/min. It is operated by a 24 V solenoid valve that is

Fabrication and Testing of High-Speed Single-Rotor and Compound-Rotor Systems

Science.gov (United States)

2016-04-05

laser engraved scales on the base and table and a 1/4" Jacobs drill chuck and key. 7.2 Specifications Max clearance, table to spindle 9.00" (229 mm...This flow control valve is rated for a peak pressure of 315 bar and a maximum flow rate of 330 l/min. It is operated by a 24 V solenoid valve that is

Combination spindle-drive system for high precision machining

Science.gov (United States)

Gerth, Howard L.

1977-07-26

A combination spindle-drive is provided for fabrication of optical quality surface finishes. Both the spindle-and-drive utilize the spindle bearings for support, thereby removing the conventional drive-means bearings as a source of vibration. An airbearing spindle is modified to carry at the drive end a highly conductive cup-shaped rotor which is aligned with a stationary stator to produce torque in the cup-shaped rotor through the reaction of eddy currents induced in the rotor. This arrangement eliminates magnetic attraction forces and all force is in the form of torque on the cup-shaped rotor.

Sleep spindles predict stress-related increases in sleep disturbances

Directory of Open Access Journals (Sweden)

Thien Thanh eDang-Vu

2015-02-01

Full Text Available Background and Aim: Predisposing factors place certain individuals at higher risk for insomnia, especially in the presence of precipitating conditions such as stressful life events. Sleep spindles have been shown to play an important role in the preservation of sleep continuity. Lower spindle density might thus constitute an objective predisposing factor for sleep reactivity to stress. The aim of this study was therefore to evaluate the relationship between baseline sleep spindle density and the prospective change in insomnia symptoms in response to a standardized academic stressor. Methods: 12 healthy students had a polysomnography (PSG recording during a period of lower stress at the beginning of the academic semester, along with an assessment of insomnia complaints using the Insomnia Severity Index (ISI. They completed a second ISI assessment at the end of the semester, a period coinciding with the week prior to final examinations and thus higher stress. Spindle density, amplitude, duration and frequency, as well as sigma power were computed from C4-O2 electroencephalography (EEG derivation during stages N2-N3 of non-rapid-eye-movement (NREM sleep, across the whole night and for each NREM sleep period. To test for the relationship between spindle density and changes in insomnia symptoms in response to academic stress, spindle measurements at baseline were correlated with changes in ISI across the academic semester.Results: Spindle density (as well as spindle amplitude and sigma power, particularly during the first NREM sleep period, negatively correlated with changes in ISI (p < 0.05. Conclusion: Lower spindle activity, especially at the beginning of the night, prospectively predicted larger increases in insomnia symptoms in response to stress. This result indicates that individual differences in sleep spindle activity contribute to the differential vulnerability to sleep disturbances in the face of precipitating factors.

CENP-W plays a role in maintaining bipolar spindle structure.

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Agnieszka Kaczmarczyk

Full Text Available The CENP-W/T complex was previously reported to be required for mitosis. HeLa cells depleted of CENP-W displayed profound mitotic defects, with mitotic timing delay, disorganized prometaphases and multipolar spindles as major phenotypic consequences. In this study, we examined the process of multipolar spindle formation induced by CENP-W depletion. Depletion of CENP-W in HeLa cells labeled with histone H2B and tubulin fluorescent proteins induced rapid fragmentation of originally bipolar spindles in a high proportion of cells. CENP-W depletion was associated with depletion of Hec1 at kinetochores. The possibility of promiscuous centrosomal duplication was ruled out by immunofluorescent examination of centrioles. However, centrioles were frequently observed to be abnormally split. In addition, a large proportion of the supernumerary poles lacked centrioles, but were positively stained with different centrosomal markers. These observations suggested that perturbation in spindle force distribution caused by defective kinetochores could contribute to a mechanical mechanism for spindle pole disruption. 'Spindle free' nocodazole arrested cells did not exhibit pole fragmentation after CENP-W depletion, showing that pole fragmentation is microtubule dependent. Inhibition of centrosome separation by monastrol reduced the incidence of spindle pole fragmentation, indicating that Eg5 plays a role in spindle pole disruption. Surprisingly, CENP-W depletion rescued the monopolar spindle phenotype of monastrol treatment, with an increased frequency of bipolar spindles observed after CENP-W RNAi. We overexpressed the microtubule cross-linking protein TPX2 to create spindle poles stabilized by the microtubule cross-linking activity of TPX2. Spindle pole fragmentation was suppressed in a TPX2-dependent fashion. We propose that CENP-W, by influencing proper kinetochore assembly, particularly microtubule docking sites, can confer spindle pole resistance to traction

CENP-W Plays a Role in Maintaining Bipolar Spindle Structure

Science.gov (United States)

Kaczmarczyk, Agnieszka; Sullivan, Kevin F.

2014-01-01

The CENP-W/T complex was previously reported to be required for mitosis. HeLa cells depleted of CENP-W displayed profound mitotic defects, with mitotic timing delay, disorganized prometaphases and multipolar spindles as major phenotypic consequences. In this study, we examined the process of multipolar spindle formation induced by CENP-W depletion. Depletion of CENP-W in HeLa cells labeled with histone H2B and tubulin fluorescent proteins induced rapid fragmentation of originally bipolar spindles in a high proportion of cells. CENP-W depletion was associated with depletion of Hec1 at kinetochores. The possibility of promiscuous centrosomal duplication was ruled out by immunofluorescent examination of centrioles. However, centrioles were frequently observed to be abnormally split. In addition, a large proportion of the supernumerary poles lacked centrioles, but were positively stained with different centrosomal markers. These observations suggested that perturbation in spindle force distribution caused by defective kinetochores could contribute to a mechanical mechanism for spindle pole disruption. ‘Spindle free’ nocodazole arrested cells did not exhibit pole fragmentation after CENP-W depletion, showing that pole fragmentation is microtubule dependent. Inhibition of centrosome separation by monastrol reduced the incidence of spindle pole fragmentation, indicating that Eg5 plays a role in spindle pole disruption. Surprisingly, CENP-W depletion rescued the monopolar spindle phenotype of monastrol treatment, with an increased frequency of bipolar spindles observed after CENP-W RNAi. We overexpressed the microtubule cross-linking protein TPX2 to create spindle poles stabilized by the microtubule cross-linking activity of TPX2. Spindle pole fragmentation was suppressed in a TPX2-dependent fashion. We propose that CENP-W, by influencing proper kinetochore assembly, particularly microtubule docking sites, can confer spindle pole resistance to traction forces exerted

Spatial signals link exit from mitosis to spindle position.

Science.gov (United States)

Falk, Jill Elaine; Tsuchiya, Dai; Verdaasdonk, Jolien; Lacefield, Soni; Bloom, Kerry; Amon, Angelika

2016-05-11

In budding yeast, if the spindle becomes mispositioned, cells prevent exit from mitosis by inhibiting the mitotic exit network (MEN). The MEN is a signaling cascade that localizes to spindle pole bodies (SPBs) and activates the phosphatase Cdc14. There are two competing models that explain MEN regulation by spindle position. In the 'zone model', exit from mitosis occurs when a MEN-bearing SPB enters the bud. The 'cMT-bud neck model' posits that cytoplasmic microtubule (cMT)-bud neck interactions prevent MEN activity. Here we find that 1) eliminating cMT- bud neck interactions does not trigger exit from mitosis and 2) loss of these interactions does not precede Cdc14 activation. Furthermore, using binucleate cells, we show that exit from mitosis occurs when one SPB enters the bud despite the presence of a mispositioned spindle. We conclude that exit from mitosis is triggered by a correctly positioned spindle rather than inhibited by improper spindle position.

Physical Limits on the Precision of Mitotic Spindle Positioning by Microtubule Pushing forces: Mechanics of mitotic spindle positioning.

Science.gov (United States)

Howard, Jonathon; Garzon-Coral, Carlos

2017-11-01

Tissues are shaped and patterned by mechanical and chemical processes. A key mechanical process is the positioning of the mitotic spindle, which determines the size and location of the daughter cells within the tissue. Recent force and position-fluctuation measurements indicate that pushing forces, mediated by the polymerization of astral microtubules against- the cell cortex, maintain the mitotic spindle at the cell center in Caenorhabditis elegans embryos. The magnitude of the centering forces suggests that the physical limit on the accuracy and precision of this centering mechanism is determined by the number of pushing microtubules rather than by thermally driven fluctuations. In cells that divide asymmetrically, anti-centering, pulling forces generated by cortically located dyneins, in conjunction with microtubule depolymerization, oppose the pushing forces to drive spindle displacements away from the center. Thus, a balance of centering pushing forces and anti-centering pulling forces localize the mitotic spindles within dividing C. elegans cells. © 2017 The Authors. BioEssays published by Wiley Periodicals, Inc.

Inter-expert and intra-expert reliability in sleep spindle scoring

DEFF Research Database (Denmark)

Wendt, Sabrina Lyngbye; Welinder, Peter; Sørensen, Helge Bjarup Dissing

2015-01-01

Objectives To measure the inter-expert and intra-expert agreement in sleep spindle scoring, and to quantify how many experts are needed to build a reliable dataset of sleep spindle scorings. Methods The EEG dataset was comprised of 400 randomly selected 115 s segments of stage 2 sleep from 110...... with higher reliability than the estimation of spindle duration. Reliability of sleep spindle scoring can be improved by using qualitative confidence scores, rather than a dichotomous yes/no scoring system. Conclusions We estimate that 2–3 experts are needed to build a spindle scoring dataset...... with ‘substantial’ reliability (κ: 0.61–0.8), and 4 or more experts are needed to build a dataset with ‘almost perfect’ reliability (κ: 0.81–1). Significance Spindle scoring is a critical part of sleep staging, and spindles are believed to play an important role in development, aging, and diseases of the nervous...

Fission yeast cells undergo nuclear division in the absence of spindle microtubules.

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Stefania Castagnetti

2010-10-01

Full Text Available Mitosis in eukaryotic cells employs spindle microtubules to drive accurate chromosome segregation at cell division. Cells lacking spindle microtubules arrest in mitosis due to a spindle checkpoint that delays mitotic progression until all chromosomes have achieved stable bipolar attachment to spindle microtubules. In fission yeast, mitosis occurs within an intact nuclear membrane with the mitotic spindle elongating between the spindle pole bodies. We show here that in fission yeast interference with mitotic spindle formation delays mitosis only briefly and cells proceed to an unusual nuclear division process we term nuclear fission, during which cells perform some chromosome segregation and efficiently enter S-phase of the next cell cycle. Nuclear fission is blocked if spindle pole body maturation or sister chromatid separation cannot take place or if actin polymerization is inhibited. We suggest that this process exhibits vestiges of a primitive nuclear division process independent of spindle microtubules, possibly reflecting an evolutionary intermediate state between bacterial and Archeal chromosome segregation where the nucleoid divides without a spindle and a microtubule spindle-based eukaryotic mitosis.

The fission yeast spindle orientation checkpoint: a model that generates tension?

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Gachet, Yannick; Reyes, Céline; Goldstone, Sherilyn; Tournier, Sylvie

2006-10-15

In all eukaryotes, the alignment of the mitotic spindle with the axis of cell polarity is essential for accurate chromosome segregation as well as for the establishment of cell fate, and thus morphogenesis, during development. Studies in invertebrates, higher eukaryotes and yeast suggest that astral microtubules interact with the cell cortex to position the spindle. These microtubules are thought to impose pushing or pulling forces on the spindle poles to affect the rotation or movement of the spindle. In the fission yeast model, where cell division is symmetrical, spindle rotation is dependent on the interaction of astral microtubules with the cortical actin cytoskeleton. In these cells, a bub1-dependent mitotic checkpoint, the spindle orientation checkpoint (SOC), is activated when the spindles fail to align with the cell polarity axis. In this paper we review the mechanism that orientates the spindle during mitosis in fission yeast, and discuss the consequences of misorientation on metaphase progression. Copyright 2006 John Wiley & Sons, Ltd.

Triangular relationship between sleep spindle activity, general cognitive ability and the efficiency of declarative learning.

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Caroline Lustenberger

Full Text Available EEG sleep spindle activity (SpA during non-rapid eye movement (NREM sleep has been reported to be associated with measures of intelligence and overnight performance improvements. The reticular nucleus of the thalamus is generating sleep spindles in interaction with thalamocortical connections. The same system enables efficient encoding and processing during wakefulness. Thus, we examined if the triangular relationship between SpA, measures of intelligence and declarative learning reflect the efficiency of the thalamocortical system. As expected, SpA was associated with general cognitive ability, e.g. information processing speed. SpA was also associated with learning efficiency, however, not with overnight performance improvement in a declarative memory task. SpA might therefore reflect the efficiency of the thalamocortical network and can be seen as a marker for learning during encoding in wakefulness, i.e. learning efficiency.

Developmental Changes in Sleep Spindle Characteristics and Sigma Power across Early Childhood

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Ian J. McClain

2016-01-01

Full Text Available Sleep spindles, a prominent feature of the non-rapid eye movement (NREM sleep electroencephalogram (EEG, are linked to cognitive abilities. Early childhood is a time of rapid cognitive and neurophysiological maturation; however, little is known about developmental changes in sleep spindles. In this study, we longitudinally examined trajectories of multiple sleep spindle characteristics (i.e., spindle duration, frequency, integrated spindle amplitude, and density and power in the sigma frequency range (10–16 Hz across ages 2, 3, and 5 years (n=8; 3 males. At each time point, nocturnal sleep EEG was recorded in-home after 13-h of prior wakefulness. Spindle duration, integrated spindle amplitude, and sigma power increased with age across all EEG derivations (C3A2, C4A1, O2A1, and O1A2; all ps < 0.05. We also found a developmental decrease in mean spindle frequency (p<0.05 but no change in spindle density with increasing age. Thus, sleep spindles increased in duration and amplitude but decreased in frequency across early childhood. Our data characterize early developmental changes in sleep spindles, which may advance understanding of thalamocortical brain connectivity and associated lifelong disease processes. These findings also provide unique insights into spindle ontogenesis in early childhood and may help identify electrophysiological features related to healthy and aberrant brain maturation.

WiMAX OFDM system simulation and sub-system FPGA implementation

International Nuclear Information System (INIS)

Elaskary, A.M.F.

2009-01-01

Orthogonal frequency division multiplexing (OFDM) has been used in many wireless communication systems also it is gaining a lot of attention for the next generations of mobile communication systems. OFDM is considered a good candidate for wireless systems because it has high bandwidth efficiency and can transmit at very high data rate in multi path, interference , and fading environment. in general OFDM has widely been studied and implemented to combat transmission channel impairments, but some challenges still facing OFDM in transmission system implementation especially for recent and future applications. One of these important applications is the worldwide interoperability for microwave access (WiMAX) system. According to the IEEE 802.16 standards, WiMAX is considered as a good solution for last mile connection at crowded areas and a high-speed internet connection to mobile vehicles with speed of up to 300 km/h. This thesis studies OFDM system in details and proposes simulink models for simulating OFDM impairments and its effects on system performance. This study has been used for building up system level and end to end WiMAX OFDM transmitter/receiver which follows published specifications in IEEE 802.16 standards using mat lab/simulink.

Spinal spindle cell haemangioma: an atypical location.

Science.gov (United States)

Talan-Hranilović, J; Vucić, M; Sajko, T; Bedek, D; Tomić, K; Lupret, V

2007-03-01

We present a case of the 31-year-old male patient who complained of weakness in both legs and progressed slowly. Neuroimagine of the thoracic spine showed an intraspinal, extradural mass lesion, measuring 5.3 x 1.2 cm at the Th1-Th3 level. Histologically the lesion was a spindle cell haemangioma composed of dilated vascular spaces and a proliferation of bland appearing interspersed spindle cells. Immunohistochemical analysis was diffusely positive for VIM, SMA and focally for CD34. This lesion is uncommon and shows a predilection for distal extremities. Spindle cell haemangioma within the spine has not been previously reported in the literature.

Local sleep spindle modulations in relation to specific memory cues

NARCIS (Netherlands)

Cox, R.; Hofman, W.F.; de Boer, M.; Talamini, L.M.

2014-01-01

Sleep spindles have been connected to memory processes in various ways. In addition, spindles appear to be modulated at the local cortical network level. We investigated whether cueing specific memories during sleep leads to localized spindle modulations in humans. During learning of word-location

Dual mechanism controls asymmetric spindle position in ascidian germ cell precursors.

Science.gov (United States)

Prodon, François; Chenevert, Janet; Hébras, Céline; Dumollard, Rémi; Faure, Emmanuel; Gonzalez-Garcia, Jose; Nishida, Hiroki; Sardet, Christian; McDougall, Alex

2010-06-01

Mitotic spindle orientation with respect to cortical polarity cues generates molecularly distinct daughter cells during asymmetric cell division (ACD). However, during ACD it remains unknown how the orientation of the mitotic spindle is regulated by cortical polarity cues until furrowing begins. In ascidians, the cortical centrosome-attracting body (CAB) generates three successive unequal cleavages and the asymmetric segregation of 40 localized postplasmic/PEM RNAs in germ cell precursors from the 8-64 cell stage. By combining fast 4D confocal fluorescence imaging with gene-silencing and classical blastomere isolation experiments, we show that spindle repositioning mechanisms are active from prometaphase until anaphase, when furrowing is initiated in B5.2 cells. We show that the vegetal-most spindle pole/centrosome is attracted towards the CAB during prometaphase, causing the spindle to position asymmetrically near the cortex. Next, during anaphase, the opposite spindle pole/centrosome is attracted towards the border with neighbouring B5.1 blastomeres, causing the spindle to rotate (10 degrees /minute) and migrate (3 microm/minute). Dynamic 4D fluorescence imaging of filamentous actin and plasma membrane shows that precise orientation of the cleavage furrow is determined by this second phase of rotational spindle displacement. Furthermore, in pairs of isolated B5.2 blastomeres, the second phase of rotational spindle displacement was lost. Finally, knockdown of PEM1, a protein localized in the CAB and required for unequal cleavage in B5.2 cells, completely randomizes spindle orientation. Together these data show that two separate mechanisms active during mitosis are responsible for spindle positioning, leading to precise orientation of the cleavage furrow during ACD in the cells that give rise to the germ lineage in ascidians.

Sleep spindles and intelligence in early childhood-developmental and trait-dependent aspects.

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Ujma, Péter P; Sándor, Piroska; Szakadát, Sára; Gombos, Ferenc; Bódizs, Róbert

2016-12-01

Sleep spindles act as a powerful marker of individual differences in cognitive ability. Sleep spindle parameters correlate with both age-related changes in cognitive abilities and with the age-independent concept of IQ. While some studies have specifically demonstrated the relationship between sleep spindles and intelligence in young children, our previous work in older subjects revealed sex differences in the sleep spindle correlates of IQ, which was never investigated in small children before. We investigated the relationship between age, Raven Colored Progressive Matrices (CPM) scores and sleep spindles in 28 young children (age 4-8 years, 15 girls). We specifically investigated sex differences in the psychometric correlates of sleep spindles. We also aimed to separate the correlates of sleep spindles that are because of age-related maturation from other effects that reflect an age-independent relationship between sleep spindles and general intelligence. Our results revealed a modest positive correlation between fast spindle amplitude and age. Raven CPM scores positively correlated with both slow and fast spindle amplitude, but this effect remained a tendency in males and vanished after correcting for the effects of age. Age-corrected correlations between Raven CPM scores and both slow and fast spindle amplitude were only significant in females. Overall, our results show that in male children sleep spindles are a maturational marker, but in female children they indicate trait-like intelligence, in line with previous studies in adolescent and adult subjects. Thalamocortical white matter connectivity may be the underlying mechanism behind both higher spindle amplitude and higher intelligence in female, but not male subjects. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Sleep Spindles as an Electrographic Element: Description and Automatic Detection Methods

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Dorothée Coppieters ’t Wallant

2016-01-01

Full Text Available Sleep spindle is a peculiar oscillatory brain pattern which has been associated with a number of sleep (isolation from exteroceptive stimuli, memory consolidation and individual characteristics (intellectual quotient. Oddly enough, the definition of a spindle is both incomplete and restrictive. In consequence, there is no consensus about how to detect spindles. Visual scoring is cumbersome and user dependent. To analyze spindle activity in a more robust way, automatic sleep spindle detection methods are essential. Various algorithms were developed, depending on individual research interest, which hampers direct comparisons and meta-analyses. In this review, sleep spindle is first defined physically and topographically. From this general description, we tentatively extract the main characteristics to be detected and analyzed. A nonexhaustive list of automatic spindle detection methods is provided along with a description of their main processing principles. Finally, we propose a technique to assess the detection methods in a robust and comparable way.

Muscle Spindles and Locomotor Control-An Unrecognized Falls Determinant?

OpenAIRE

Marks Ray

2015-01-01

BACKGROUND: Historically, evidence muscle spindles might be involved in locomotion was provided by their presence in tetrapod antigravity muscles associated with posture and locomotion. Later, Brodal (1962) noted muscle spindles in all muscles of locomotion. To unravel the complexity of the muscle spindle and its role in human locomotor control many investigators have since conducted lesion and/or anaesthesia studies in subhuman species and human contexts. QUESTIONS: How ...

Sleep spindling and fluid intelligence across adolescent development: sex matters

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Róbert eBódizs

2014-11-01

Full Text Available Evidence supports the intricate relationship between sleep electroencephalogram (EEG spindling and cognitive abilities in children and adults. Although sleep EEG changes during adolescence index fundamental brain reorganization, a detailed analysis of sleep spindling and the spindle-intelligence relationship was not yet provided for adolescents. Therefore, adolescent development of sleep spindle oscillations were studied in a home polysomnographic study focusing on the effects of chronological age and developmentally acquired overall mental efficiency (fluid IQ with sex as a potential modulating factor. Subjects were 24 healthy adolescents (12 males with an age range of 15–22 years (mean: 18 years and fluid IQ of 91-126 (mean: 104.12, Raven Progressive Matrices Test. Slow spindles (SSs and fast spindles (FSs were analyzed in 21 EEG derivations by using the individual adjustment method. A significant age-dependent increase in average FS density (r = .57; p = .005 was found. Moreover, fluid IQ correlated with FS density (r = .43; p = .04 and amplitude (r = .41; p = .049. The latter effects were entirely driven by particularly reliable FS-IQ correlations in females [r = .80 (p = .002 and r = .67 (p = .012, for density and amplitude, respectively]. Region-specific analyses revealed that these correlations peak in the fronto-central regions. The control of the age-dependence of FS measures and IQ scores did not considerably reduce the spindle-IQ correlations with respect to FS density. The only positive spindle-index of fluid IQ in males turned out to be the frequency of FSs (r = .60, p = .04. Increases in FS density during adolescence may index reshaped structural connectivity related to white matter maturation in the late developing human brain. The continued development over this age range of cognitive functions is indexed by specific measures of sleep spindling unravelling gender differences in adolescent brain maturation and perhaps cognitive

Thermal Characteristic Analysis and Experimental Study of a Spindle-Bearing System

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Li Wu

2016-07-01

Full Text Available In this paper, a thermo-mechanical coupling analysis model of the spindle-bearing system based on Hertz’s contact theory and a point contact non-Newtonian thermal elastohydrodynamic lubrication (EHL theory are developed. In this model, the effect of preload, centrifugal force, the gyroscopic moment, and the lubrication state of the spindle-bearing system are considered. According to the heat transfer theory, the mathematical model for the temperature field of the spindle system is developed and the effect of the spindle cooling system on the spindle temperature distribution is analyzed. The theoretical simulations and the experimental results indicate that the bearing preload has great effect on the frictional heat generation; the cooling fluid has great effect on the heat balance of the spindle system. If a steady-state heat balance between the friction heat generation and the cooling system cannot be reached, thermally-induced preload will lead to a further increase of the frictional heat generation and then cause the thermal failure of the spindle.

Live imaging of spindle pole disorganization in docetaxel-treated multicolor cells

International Nuclear Information System (INIS)

Sakaushi, Shinji; Nishida, Kumi; Minamikawa, Harumi; Fukada, Takashi; Oka, Shigenori; Sugimoto, Kenji

2007-01-01

Treatment of cells with docetaxel at low concentrations induces aberrant bipolar spindles of which two centrosomes stay at only one pole, and also induces multipolar spindles. To gain insight into the relations between centrosome impairment and structural defects of the spindle, live-cell imaging was performed on a human MDA Auro/imp/H3 cell line in which centrosomes/mitotic spindles, nuclear membrane and chromatin were simultaneously visualized by fluorescent proteins. In the presence of docetaxel at IC 50 concentration, the centrosomes did not segregate, and multiple aster-like structures ectopically arose around the disappearing nuclear membrane. Those ectopic structures formed an acentrosomal pole opposing to the two-centrosomes-containing pole. In late metaphase, one pole often fragmented into multiple spindle poles, leading multipolar division. These results suggest that spindle pole fragility may be induced by centrosome impairment, and collapse of the pole may contribute to induction of aneuploid daughter cells

Using Micromanipulation to Analyze Control of Vertebrate Meiotic Spindle Size

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Jun Takagi

2013-10-01

Full Text Available The polymerization/depolymerization dynamics of microtubules (MTs have been reported to contribute to control of the size and shape of spindles, but quantitative analysis of how the size and shape correlate with the amount and density of MTs in the spindle remains incomplete. Here, we measured these parameters using 3D microscopy of meiotic spindles that self-organized in Xenopus egg extracts and presented a simple equation describing the relationship among these parameters. To examine the validity of the equation, we cut the spindle into two fragments along the pole-to-pole axis by micromanipulation techniques that rapidly decrease the amount of MTs. The spheroidal shape spontaneously recovered within 5 min, but the size of each fragment remained small. The equation we obtained quantitatively describes how the spindle size correlates with the amount of MTs while maintaining the shape and the MT density.

Parietal Fast Sleep Spindle Density Decrease in Alzheimer's Disease and Amnesic Mild Cognitive Impairment

Science.gov (United States)

Gorgoni, Maurizio; Lauri, Giulia; Truglia, Ilaria; Cordone, Susanna; Sarasso, Simone; Scarpelli, Serena; Mangiaruga, Anastasia; D'Atri, Aurora; Tempesta, Daniela; Ferrara, Michele; Marra, Camillo; Rossini, Paolo Maria; De Gennaro, Luigi

2016-01-01

Several studies have identified two types of sleep spindles: fast (13–15 Hz) centroparietal and slow (11–13 Hz) frontal spindles. Alterations in spindle activity have been observed in Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). Only few studies have separately assessed fast and slow spindles in these patients showing a reduction of fast spindle count, but the possible local specificity of this phenomenon and its relation to cognitive decline severity are not clear. Moreover, fast and slow spindle density have never been assessed in AD/MCI. We have assessed fast and slow spindles in 15 AD patients, 15 amnesic MCI patients, and 15 healthy elderly controls (HC). Participants underwent baseline polysomnographic recording (19 cortical derivations). Spindles during nonrapid eye movements sleep were automatically detected, and spindle densities of the three groups were compared in the derivations where fast and slow spindles exhibited their maximum expression (parietal and frontal, resp.). AD and MCI patients showed a significant parietal fast spindle density decrease, positively correlated with Minimental State Examination scores. Our results suggest that AD-related changes in spindle density are specific for frequency and location, are related to cognitive decline severity, and may have an early onset in the pathology development. PMID:27066274

Sleep spindling and fluid intelligence across adolescent development: sex matters.

Science.gov (United States)

Bódizs, Róbert; Gombos, Ferenc; Ujma, Péter P; Kovács, Ilona

2014-01-01

Evidence supports the intricate relationship between sleep electroencephalogram (EEG) spindling and cognitive abilities in children and adults. Although sleep EEG changes during adolescence index fundamental brain reorganization, a detailed analysis of sleep spindling and the spindle-intelligence relationship was not yet provided for adolescents. Therefore, adolescent development of sleep spindle oscillations were studied in a home polysomnographic study focusing on the effects of chronological age and developmentally acquired overall mental efficiency (fluid IQ) with sex as a potential modulating factor. Subjects were 24 healthy adolescents (12 males) with an age range of 15-22 years (mean: 18 years) and fluid IQ of 91-126 (mean: 104.12, Raven Progressive Matrices Test). Slow spindles (SSs) and fast spindles (FSs) were analyzed in 21 EEG derivations by using the individual adjustment method (IAM). A significant age-dependent increase in average FS density (r = 0.57; p = 0.005) was found. Moreover, fluid IQ correlated with FS density (r = 0.43; p = 0.04) and amplitude (r = 0.41; p = 0.049). The latter effects were entirely driven by particularly reliable FS-IQ correlations in females [r = 0.80 (p = 0.002) and r = 0.67 (p = 0.012), for density and amplitude, respectively]. Region-specific analyses revealed that these correlations peak in the fronto-central regions. The control of the age-dependence of FS measures and IQ scores did not considerably reduce the spindle-IQ correlations with respect to FS density. The only positive spindle-index of fluid IQ in males turned out to be the frequency of FSs (r = 0.60, p = 0.04). Increases in FS density during adolescence may index reshaped structural connectivity related to white matter maturation in the late developing human brain. The continued development over this age range of cognitive functions is indexed by specific measures of sleep spindling unraveling gender differences in adolescent brain maturation and perhaps

Limits, modeling and design of high-speed permanent magnet machines

NARCIS (Netherlands)

Borisavljevic, A.

2011-01-01

There is a growing number of applications that require fast-rotating machines; motivation for this thesis comes from a project in which downsized spindles for micro-machining have been researched (TU Delft Microfactory project). The thesis focuses on analysis and design of high-speed PM machines and

Noninvasive three-dimensional live imaging methodology for the spindles at meiosis and mitosis

Science.gov (United States)

Zheng, Jing-gao; Huo, Tiancheng; Tian, Ning; Chen, Tianyuan; Wang, Chengming; Zhang, Ning; Zhao, Fengying; Lu, Danyu; Chen, Dieyan; Ma, Wanyun; Sun, Jia-lin; Xue, Ping

2013-05-01

The spindle plays a crucial role in normal chromosome alignment and segregation during meiosis and mitosis. Studying spindles in living cells noninvasively is of great value in assisted reproduction technology (ART). Here, we present a novel spindle imaging methodology, full-field optical coherence tomography (FF-OCT). Without any dye labeling and fixation, we demonstrate the first successful application of FF-OCT to noninvasive three-dimensional (3-D) live imaging of the meiotic spindles within the mouse living oocytes at metaphase II as well as the mitotic spindles in the living zygotes at metaphase and telophase. By post-processing of the 3-D dataset obtained with FF-OCT, the important morphological and spatial parameters of the spindles, such as short and long axes, spatial localization, and the angle of meiotic spindle deviation from the first polar body in the oocyte were precisely measured with the spatial resolution of 0.7 μm. Our results reveal the potential of FF-OCT as an imaging tool capable of noninvasive 3-D live morphological analysis for spindles, which might be useful to ART related procedures and many other spindle related studies.

Variable current speed controller for eddy current motors

Science.gov (United States)

Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

1982-03-12

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

TFG-MET fusion in an infantile spindle cell sarcoma with neural features

NARCIS (Netherlands)

Flucke, U.E.; Noesel, M.M. van; Wijnen, M.; Zhang, L.; Chen, C.L.; Sung, Y.S.; Antonescu, C.R.

2017-01-01

An increasing number of congenital and infantile sarcomas displaying a primitive, monomorphic spindle cell phenotype have been characterized to harbor recurrent gene fusions, including infantile fibrosarcoma and congenital spindle cell rhabdomyosarcoma. Here, we report an unusual spindle cell

Min-Max Spaces and Complexity Reduction in Min-Max Expansions

Energy Technology Data Exchange (ETDEWEB)

Gaubert, Stephane, E-mail: Stephane.Gaubert@inria.fr [Ecole Polytechnique, INRIA and CMAP (France); McEneaney, William M., E-mail: wmceneaney@ucsd.edu [University of California San Diego, Dept. of Mech. and Aero. Eng. (United States)

2012-06-15

Idempotent methods have been found to be extremely helpful in the numerical solution of certain classes of nonlinear control problems. In those methods, one uses the fact that the value function lies in the space of semiconvex functions (in the case of maximizing controllers), and approximates this value using a truncated max-plus basis expansion. In some classes, the value function is actually convex, and then one specifically approximates with suprema (i.e., max-plus sums) of affine functions. Note that the space of convex functions is a max-plus linear space, or moduloid. In extending those concepts to game problems, one finds a different function space, and different algebra, to be appropriate. Here we consider functions which may be represented using infima (i.e., min-max sums) of max-plus affine functions. It is natural to refer to the class of functions so represented as the min-max linear space (or moduloid) of max-plus hypo-convex functions. We examine this space, the associated notion of duality and min-max basis expansions. In using these methods for solution of control problems, and now games, a critical step is complexity-reduction. In particular, one needs to find reduced-complexity expansions which approximate the function as well as possible. We obtain a solution to this complexity-reduction problem in the case of min-max expansions.

Timely Endocytosis of Cytokinetic Enzymes Prevents Premature Spindle Breakage during Mitotic Exit.

Directory of Open Access Journals (Sweden)

Cheen Fei Chin

2016-07-01

Full Text Available Cytokinesis requires the spatio-temporal coordination of membrane deposition and primary septum (PS formation at the division site to drive acto-myosin ring (AMR constriction. It has been demonstrated that AMR constriction invariably occurs only after the mitotic spindle disassembly. It has also been established that Chitin Synthase II (Chs2p neck localization precedes mitotic spindle disassembly during mitotic exit. As AMR constriction depends upon PS formation, the question arises as to how chitin deposition is regulated so as to prevent premature AMR constriction and mitotic spindle breakage. In this study, we propose that cells regulate the coordination between spindle disassembly and AMR constriction via timely endocytosis of cytokinetic enzymes, Chs2p, Chs3p, and Fks1p. Inhibition of endocytosis leads to over accumulation of cytokinetic enzymes during mitotic exit, which accelerates the constriction of the AMR, and causes spindle breakage that eventually could contribute to monopolar spindle formation in the subsequent round of cell division. Intriguingly, the mitotic spindle breakage observed in endocytosis mutants can be rescued either by deleting or inhibiting the activities of, CHS2, CHS3 and FKS1, which are involved in septum formation. The findings from our study highlight the importance of timely endocytosis of cytokinetic enzymes at the division site in safeguarding mitotic spindle integrity during mitotic exit.

Max Jakobson : Kommunismisse tuleb suhtuda objektiivselt / Max Jakobson

Index Scriptorium Estoniae

Jakobson, Max, 1923-2013

2002-01-01

President Rüütel andis Soome tuntud diplomaadile ja Inimsusevastaste Kuritegude Uurimise Rahvusvahelise Komisjoni (IKURK) esimehele Max Jakobsonile Maarjamaa Risti I klassi teenetemärgi. Tseremooniajärgne intervjuu Max Jakobsoniga

Fast and slow spindles during the sleep slow oscillation: disparate coalescence and engagement in memory processing.

Science.gov (United States)

Mölle, Matthias; Bergmann, Til O; Marshall, Lisa; Born, Jan

2011-10-01

Thalamo-cortical spindles driven by the up-state of neocortical slow (memory consolidation during sleep. We examined interactions between SOs and spindles in human slow wave sleep, focusing on the presumed existence of 2 kinds of spindles, i.e., slow frontocortical and fast centro-parietal spindles. Two experiments were performed in healthy humans (24.5 ± 0.9 y) investigating undisturbed sleep (Experiment I) and the effects of prior learning (word paired associates) vs. non-learning (Experiment II) on multichannel EEG recordings during sleep. Only fast spindles (12-15 Hz) were synchronized to the depolarizing SO up-state. Slow spindles (9-12 Hz) occurred preferentially at the transition into the SO down-state, i.e., during waning depolarization. Slow spindles also revealed a higher probability to follow rather than precede fast spindles. For sequences of individual SOs, fast spindle activity was largest for "initial" SOs, whereas SO amplitude and slow spindle activity were largest for succeeding SOs. Prior learning enhanced this pattern. The finding that fast and slow spindles occur at different times of the SO cycle points to disparate generating mechanisms for the 2 kinds of spindles. The reported temporal relationships during SO sequences suggest that fast spindles, driven by the SO up-state feed back to enhance the likelihood of succeeding SOs together with slow spindles. By enforcing such SO-spindle cycles, particularly after prior learning, fast spindles possibly play a key role in sleep-dependent memory processing.

Force encoding in muscle spindles during stretch of passive muscle.

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Kyle P Blum

2017-09-01

Full Text Available Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle

Force encoding in muscle spindles during stretch of passive muscle.

Science.gov (United States)

Blum, Kyle P; Lamotte D'Incamps, Boris; Zytnicki, Daniel; Ting, Lena H

2017-09-01

Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs) of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt) predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening) of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle lengthening conditions

Automatic Sleep Spindle Detection and Genetic Influence Estimation Using Continuous Wavelet Transform

NARCIS (Netherlands)

Adamczyk, M.; Genzel, L.K.E.; Dresler, M.; Steiger, A.; Friess, E.

2015-01-01

Mounting evidence for the role of sleep spindles in neuroplasticity has led to an increased interest in these non-rapid eye movement (NREM) sleep oscillations. It has been hypothesized that fast and slow spindles might play a different role in memory processing. Here, we present a new sleep spindle

Spindle neurons of the human anterior cingulate cortex

Science.gov (United States)

Nimchinsky, E. A.; Vogt, B. A.; Morrison, J. H.; Hof, P. R.; Bloom, F. E. (Principal Investigator)

1995-01-01

The human anterior cingulate cortex is distinguished by the presence of an unusual cell type, a large spindle neuron in layer Vb. This cell has been noted numerous times in the historical literature but has not been studied with modern neuroanatomic techniques. For instance, details regarding the neuronal class to which these cells belong and regarding their precise distribution along both ventrodorsal and anteroposterior axes of the cingulate gyrus are still lacking. In the present study, morphological features and the anatomic distribution of this cell type were studied using computer-assisted mapping and immunocytochemical techniques. Spindle neurons are restricted to the subfields of the anterior cingulate cortex (Brodmann's area 24), exhibiting a greater density in anterior portions of this area than in posterior portions, and tapering off in the transition zone between anterior and posterior cingulate cortex. Furthermore, a majority of the spindle cells at any level is located in subarea 24b on the gyral surface. Immunocytochemical analysis revealed that the neurofilament protein triple was present in a large percentage of these neurons and that they did not contain calcium-binding proteins. Injections of the carbocyanine dye DiI into the cingulum bundle revealed that these cells are projection neurons. Finally, spindle cells were consistently affected in Alzheimer's disease cases, with an overall loss of about 60%. Taken together, these observations indicate that the spindle cells of the human cingulate cortex represent a morphological subpopulation of pyramidal neurons whose restricted distribution may be associated with functionally distinct areas.

Cross-layer ultrasound video streaming over mobile WiMAX and HSUPA networks.

Science.gov (United States)

Alinejad, Ali; Philip, Nada Y; Istepanian, Robert S H

2012-01-01

It is well known that the evolution of 4G-based mobile multimedia network systems will contribute significantly to future mobile healthcare (m-health) applications that require high bandwidth and fast data rates. Central to the success of such emerging applications is the compatibility of broadband networks, such as mobile Worldwide Interoperability For Microwave Access (WiMAX) and High-Speed Uplink Packet Access (HSUPA), and especially their rate adaption issues combined with the acceptable real-time medical quality of service requirements. In this paper, we address the relevant challenges of cross-layer design requirements for real-time rate adaptation of ultrasound video streaming in mobile WiMAX and HSUPA networks. A comparative performance analysis of such approach is validated in two experimental m-health test bed systems for both mobile WiMAX and HSUPA networks. The experimental results have shown an improved performance of mobile WiMAX compared to the HSUPA using the same cross-layer optimization approach.

Intercentrosomal angular separation during mitosis plays a crucial role for maintaining spindle stability

Science.gov (United States)

Sutradhar, S.; Basu, S.; Paul, R.

2015-10-01

Cell division through proper spindle formation is one of the key puzzles in cell biology. In most mammalian cells, chromosomes spontaneously arrange to achieve a stable bipolar spindle during metaphase which eventually ensures proper segregation of the DNA into the daughter cells. In this paper, we present a robust three-dimensional mechanistic model to investigate the formation and maintenance of a bipolar mitotic spindle in mammalian cells under different physiological constraints. Using realistic parameters, we test spindle viability by measuring the spindle length and studying the chromosomal configuration. The model strikingly predicts a feature of the spindle instability arising from the insufficient intercentrosomal angular separation and impaired sliding of the interpolar microtubules. In addition, our model successfully reproduces chromosomal patterns observed in mammalian cells, when activity of different motor proteins is perturbed.

Relationship between focal penicillin spikes and cortical spindles in the cerveau isolé cat.

Science.gov (United States)

McLachlan, R S; Kaibara, M; Girvin, J P

1983-01-01

Using the unanesthetized, cerveau isolé preparation in the cat, the association between artificially induced penicillin (PCN) spikes and spontaneously occurring electrocorticographic (ECoG) spindles was investigated. Spikes were elicited by surface application of small pledgets of PCN. After the application of PCN, there was a decrease in spindle amplitude but no change in frequency, duration, or spindle wave frequency in the area of the focus. Examination of the times of occurrence of the spikes and spindles disclosed that in the majority of cases, within a few minutes of the initiation of the foci, there was very high simultaneity, usually 100% between the occurrences of these two events. Examination of the times of occurrence of the spikes within the ECoG spindles failed to disclose any compelling evidence which would favor either the hypothesis that spikes "trigger" spindles or the hypothesis that spindles predispose to focal spikes. Thus, whether spikes trigger spindles, or spikes simply occur in a nonspecific manner during the occurrence of the spindle, or whether it is a combination of both these explanations, must remain an open question on the basis of the data available.

Sleep Spindles and Intelligence in Early Childhood--Developmental and Trait-Dependent Aspects

Science.gov (United States)

Ujma, Péter P.; Sándor, Piroska; Szakadát, Sára; Gombos, Ferenc; Bódizs, Róbert

2016-01-01

Sleep spindles act as a powerful marker of individual differences in cognitive ability. Sleep spindle parameters correlate with both age-related changes in cognitive abilities and with the age-independent concept of IQ. While some studies have specifically demonstrated the relationship between sleep spindles and intelligence in young children, our…

Spindle-shaped Microstructures: Potential Models for Planktonic Life Forms on Other Worlds

Science.gov (United States)

Oehler, Dorothy Z.; Walsh, Maud M.; Sugitani, Kenichiro; House, Christopher H.

2014-01-01

Spindle-shaped, organic microstructures ("spindles") are now known from Archean cherts in three localities (Figs. 1-4): The 3 Ga Farrel Quartzite from the Pilbara of Australia [1]; the older, 3.3-3.4 Ga Strelley Pool Formation, also from the Pilbara of Australia [2]; and the 3.4 Ga Kromberg Formation of the Barberton Mountain Land of South Africa [3]. Though the spindles were previously speculated to be pseudofossils or epigenetic organic contaminants, a growing body of data suggests that these structures are bona fide microfossils and further, that they are syngenetic with the Archean cherts in which they occur [1-2, 4-10]. As such, the spindles are among some of the oldest-known organically preserved microfossils on Earth. Moreover, recent delta C-13 study of individual spindles from the Farrel Quartzite (using Secondary Ion Mass Spectrometry [SIMS]) suggests that the spindles may have been planktonic (living in open water), as opposed to benthic (living as bottom dwellers in contact with muds or sediments) [9]. Since most Precambrian microbiotas have been described from benthic, matforming communities, a planktonic lifestyle for the spindles suggests that these structures could represent a segment of the Archean biosphere that is poorly known. Here we synthesize the recent work on the spindles, and we add new observations regarding their geographic distribution, robustness, planktonic habit, and long-lived success. We then discuss their potential evolutionary and astrobiological significance.

Remembering Max Boisot

DEFF Research Database (Denmark)

Sanchez, Ron

2013-01-01

This chapter offers some reflections on Max Boisot and his extraordinary intellect drawn from our 15 years of exchanging and crafting ideas together. I first comment on the process of working with Max, and then suggest some of the remarkable qualities of thought that I believe distinguished Max's...... these qualities of thought are also reflected in Max's individual work and especially in his crowning achievement, the Information-Space Model....

Sleep Spindle Detection and Prediction Using a Mixture of Time Series and Chaotic Features

Directory of Open Access Journals (Sweden)

Amin Hekmatmanesh

2017-01-01

Full Text Available It is well established that sleep spindles (bursts of oscillatory brain electrical activity are significant indicators of learning, memory and some disease states. Therefore, many attempts have been made to detect these hallmark patterns automatically. In this pilot investigation, we paid special attention to nonlinear chaotic features of EEG signals (in combination with linear features to investigate the detection and prediction of sleep spindles. These nonlinear features included: Higuchi's, Katz's and Sevcik's Fractal Dimensions, as well as the Largest Lyapunov Exponent and Kolmogorov's Entropy. It was shown that the intensity map of various nonlinear features derived from the constructive interference of spindle signals could improve the detection of the sleep spindles. It was also observed that the prediction of sleep spindles could be facilitated by means of the analysis of these maps. Two well-known classifiers, namely the Multi-Layer Perceptron (MLP and the K-Nearest Neighbor (KNN were used to distinguish between spindle and non-spindle patterns. The MLP classifier produced a~high discriminative capacity (accuracy = 94.93%, sensitivity = 94.31% and specificity = 95.28% with significant robustness (accuracy ranging from 91.33% to 94.93%, sensitivity varying from 91.20% to 94.31%, and specificity extending from 89.79% to 95.28% in separating spindles from non-spindles. This classifier also generated the best results in predicting sleep spindles based on chaotic features. In addition, the MLP was used to find out the best time window for predicting the sleep spindles, with the experimental results reaching 97.96% accuracy.

AuroraMAX!

Science.gov (United States)

Donovan, E.; Spanswick, E. L.; Chicoine, R.; Pugsley, J.; Langlois, P.

2011-12-01

AuroraMAX is a public outreach and education initiative that brings auroral images to the public in real time. AuroraMAX utilizes an observing station located just outside Yellowknife, Canada. The station houses a digital All-Sky Imager (ASI) that collects full-colour images of the night sky every six seconds. These images are then transmitted via satellite internet to our web server, where they are made instantly available to the public. Over the last two years this program has rapidly become one of the most successful outreach programs in the history of Space Science in Canada, with hundreds of thousands of distinct visitors to the CSA AuroraMAX website, thousands of followers on social media, and hundreds of newspaper, magazine, radio, and television spots. Over the next few years, the project will expand to include a high-resolution SLR delivering real-time auroral images (also from Yellowknife), as well as a program where astronauts on the ISS will take pictures of the aurora with a handheld SLR. The objectives of AuroraMAX are public outreach and education. The ASI design, operation, and software were based on infrastructure that was developed for the highly successful ASI component of the NASA THEMIS mission as well as the Canadian Space Agency (CSA) Canadian GeoSpace Monitoring (CGSM) program. So from an education and public outreach perspective, AuroraMAX is a single camera operating in the Canadian north. On the other hand, AuroraMAX is one of nearly 40 All-Sky Imagers that are operating across North America. The AuroraMAX camera produces data that is seamlessly integrated with the CGSM ASI data, and made widely available to the Space Science community through open-access web and FTP sites. One of our objectives in the next few years is to incorporate some of the data from the THEMIS and CGSM imagers into the AuroraMAX system, to maximize viewing opportunities and generate more real-time data for public outreach. This is an exemplar of a program that

Drosophila parthenogenesis: A tool to decipher centrosomal vs acentrosomal spindle assembly pathways

International Nuclear Information System (INIS)

Riparbelli, Maria Giovanna; Callaini, Giuliano

2008-01-01

Development of unfertilized eggs in the parthenogenetic strain K23-O-im of Drosophila mercatorum requires the stochastic interactions of self-assembled centrosomes with the female chromatin. In a portion of the unfertilized eggs that do not assemble centrosomes, microtubules organize a bipolar anastral mitotic spindle around the chromatin like the one formed during the first female meiosis, suggesting that similar pathways may be operative. In the cytoplasm of eggs in which centrosomes do form, monastral and biastral spindles are found. Analysis by laser scanning confocal microscopy suggests that these spindles are derived from the stochastic interaction of astral microtubules directly with kinetochore regions or indirectly with kinetochore microtubules. Our findings are consistent with the idea that mitotic spindle assembly requires both acentrosomal and centrosomal pathways, strengthening the hypothesis that astral microtubules can dictate the organization of the spindle by capturing kinetochore microtubules

The structure of the mitotic spindle and nucleolus during mitosis in the amebo-flagellate Naegleria.

Science.gov (United States)

Walsh, Charles J

2012-01-01

Mitosis in the amebo-flagellate Naegleria pringsheimi is acentrosomal and closed (the nuclear membrane does not break down). The large central nucleolus, which occupies about 20% of the nuclear volume, persists throughout the cell cycle. At mitosis, the nucleolus divides and moves to the poles in association with the chromosomes. The structure of the mitotic spindle and its relationship to the nucleolus are unknown. To identify the origin and structure of the mitotic spindle, its relationship to the nucleolus and to further understand the influence of persistent nucleoli on cellular division in acentriolar organisms like Naegleria, three-dimensional reconstructions of the mitotic spindle and nucleolus were carried out using confocal microscopy. Monoclonal antibodies against three different nucleolar regions and α-tubulin were used to image the nucleolus and mitotic spindle. Microtubules were restricted to the nucleolus beginning with the earliest prophase spindle microtubules. Early spindle microtubules were seen as short rods on the surface of the nucleolus. Elongation of the spindle microtubules resulted in a rough cage of microtubules surrounding the nucleolus. At metaphase, the mitotic spindle formed a broad band completely embedded within the nucleolus. The nucleolus separated into two discreet masses connected by a dense band of microtubules as the spindle elongated. At telophase, the distal ends of the mitotic spindle were still completely embedded within the daughter nucleoli. Pixel by pixel comparison of tubulin and nucleolar protein fluorescence showed 70% or more of tubulin co-localized with nucleolar proteins by early prophase. These observations suggest a model in which specific nucleolar binding sites for microtubules allow mitotic spindle formation and attachment. The fact that a significant mass of nucleolar material precedes the chromosomes as the mitotic spindle elongates suggests that spindle elongation drives nucleolar division.

Direct kinetochore–spindle pole connections are not required for chromosome segregation

Science.gov (United States)

Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B.; He, Jie; Le Berre, Maël; Tikhonenko, Irina; Ault, Jeffrey G.; McEwen, Bruce F.; Chen, James K.; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M.

2014-01-01

Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes′ kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells. PMID:25023516

Direct kinetochore-spindle pole connections are not required for chromosome segregation.

Science.gov (United States)

Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B; He, Jie; Le Berre, Maël; Tikhonenko, Irina; Ault, Jeffrey G; McEwen, Bruce F; Chen, James K; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M; Khodjakov, Alexey

2014-07-21

Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes' kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the spindle equator during metaphase and segregated properly during anaphase when one of their K-fibers was severed near the kinetochore with a laser microbeam. We also found that, in normal fully assembled spindles, K-fibers of some chromosomes did not extend to the spindle pole. These K-fibers connected to adjacent K-fibers and/or nonkinetochore MTs. Poleward movement of chromosomes with short K-fibers was uncoupled from MT depolymerization at the kinetochore. Instead, these chromosomes moved by dynein-mediated transport of the entire K-fiber/kinetochore assembly. Thus, at least two distinct parallel mechanisms drive chromosome segregation in mammalian cells.

A comparison of two sleep spindle detection methods based on all night averages: individually adjusted versus fixed frequencies

Directory of Open Access Journals (Sweden)

Péter Przemyslaw Ujma

2015-02-01

Full Text Available Sleep spindles are frequently studied for their relationship with state and trait cognitive variables, and they are thought to play an important role in sleep-related memory consolidation. Due to their frequent occurrence in NREM sleep, the detection of sleep spindles is only feasible using automatic algorithms, of which a large number is available. We compared subject averages of the spindle parameters computed by a fixed frequency (11-13 Hz for slow spindles, 13-15 Hz for fast spindles automatic detection algorithm and the individual adjustment method (IAM, which uses individual frequency bands for sleep spindle detection. Fast spindle duration and amplitude are strongly correlated in the two algorithms, but there is little overlap in fast spindle density and slow spindle parameters in general. The agreement between fixed and manually determined sleep spindle frequencies is limited, especially in case of slow spindles. This is the most likely reason for the poor agreement between the two detection methods in case of slow spindle parameters. Our results suggest that while various algorithms may reliably detect fast spindles, a more sophisticated algorithm primed to individual spindle frequencies is necessary for the detection of slow spindles as well as individual variations in the number of spindles in general.

Simplified Dynamic Analysis of Grinders Spindle Node

Science.gov (United States)

Demec, Peter

2014-12-01

The contribution deals with the simplified dynamic analysis of surface grinding machine spindle node. Dynamic analysis is based on the use of the transfer matrix method, which is essentially a matrix form of method of initial parameters. The advantage of the described method, despite the seemingly complex mathematical apparatus, is primarily, that it does not require for solve the problem of costly commercial software using finite element method. All calculations can be made for example in MS Excel, which is advantageous especially in the initial stages of constructing of spindle node for the rapid assessment of the suitability its design. After detailing the entire structure of spindle node is then also necessary to perform the refined dynamic analysis in the environment of FEM, which it requires the necessary skills and experience and it is therefore economically difficult. This work was developed within grant project KEGA No. 023TUKE-4/2012 Creation of a comprehensive educational - teaching material for the article Production technique using a combination of traditional and modern information technology and e-learning.

Material Choice for spindle of machine tools

Science.gov (United States)

Gouasmi, S.; Merzoug, B.; Abba, G.; Kherredine, L.

2012-02-01

The requirements of contemporary industry and the flashing development of modern sciences impose restrictions on the majority of the elements of machines; the resulting financial constraints can be satisfied by a better output of the production equipment. As for those concerning the design, the resistance and the correct operation of the product, these require the development of increasingly precise parts, therefore the use of increasingly powerful tools [5]. The precision of machining and the output of the machine tools are generally determined by the precision of rotation of the spindle, indeed, more this one is large more the dimensions to obtain are in the zone of tolerance and the defects of shape are minimized. During the development of the machine tool, the spindle which by definition is a rotating shaft receiving and transmitting to the work piece or the cutting tool the rotational movement, must be designed according to certain optimal parameters to be able to ensure the precision required. This study will be devoted to the choice of the material of the spindle fulfilling the imposed requirements of precision.

Material Choice for spindle of machine tools

International Nuclear Information System (INIS)

Gouasmi, S; Merzoug, B; Kherredine, L; Abba, G

2012-01-01

The requirements of contemporary industry and the flashing development of modern sciences impose restrictions on the majority of the elements of machines; the resulting financial constraints can be satisfied by a better output of the production equipment. As for those concerning the design, the resistance and the correct operation of the product, these require the development of increasingly precise parts, therefore the use of increasingly powerful tools [5]. The precision of machining and the output of the machine tools are generally determined by the precision of rotation of the spindle, indeed, more this one is large more the dimensions to obtain are in the zone of tolerance and the defects of shape are minimized. During the development of the machine tool, the spindle which by definition is a rotating shaft receiving and transmitting to the work piece or the cutting tool the rotational movement, must be designed according to certain optimal parameters to be able to ensure the precision required. This study will be devoted to the choice of the material of the spindle fulfilling the imposed requirements of precision.

Pituitary spindle cell oncocytoma

Directory of Open Access Journals (Sweden)

Soledad Sosa

2018-01-01

Full Text Available Spindle cell oncocytoma is an infrequent benign non-endocrine sellar neoplasm. Due to its similar morphology to pituitary adenomas, consideration of this differential diagnosis would conduce to a more careful surgical approach in order to avoid intraoperative bleeding and aiming to a complete resection, on which depends long-term outcomes. We present the case of a 60-year-old male who complained about visual abnormalities, with computerized visual field confirmation. On biochemistry, a panhypopituitarism was detected. The brain magnetic resonance images showed a sellar mass. A non-functioning pituitary macroadenoma was presumptively diagnosed and due to the visual impairment, surgical transesphenoidal treatment was indicated. The histological diagnosis was spindle cell oncocytoma. Five months after surgery, the control image demonstrated a lesion that was considered as remnant tumor, hence radiosurgery was performed. During the follow-up, the tumor reduced its size and four years after initial treatment, the sellar resonance imaging showed disappearance of the residual tumor. Communication of new cases of this rare entity will enlarge the existing evidence and will help to determinate the most effective treatment and prognosis.

Sleep Spindles as Biomarker for Early Detection of Neurodegenerative Disorders

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to the use of sleep spindles as a novel biomarker for early diagnosis of synucleinopathies, in particular Parkinson's disease (PD). The method is based on automatic detection of sleep spindles. The method may be combined with measurements of one or more further...

Automatic sleep spindle detection: Benchmarking with fine temporal resolution using open science tools

Directory of Open Access Journals (Sweden)

Christian eO'Reilly

2015-06-01

Full Text Available Sleep spindle properties index cognitive faculties such as memory consolidation and diseases such as major depression. For this reason, scoring sleep spindle properties in polysomnographic recordings has become an important activity in both research and clinical settings. The tediousness of this manual task has motivated efforts for its automation. Although some progress has been made, increasing the temporal accuracy of spindle scoring and improving the performance assessment methodology are two aspects needing more attention. In this paper, four open-access automated spindle detectors with fine temporal resolution are proposed and tested against expert scoring of two proprietary and two open-access databases. Results highlight several findings: 1 that expert scoring and polysomnographic databases are important confounders when comparing the performance of spindle detectors tested using different databases or scorings; 2 because spindles are sparse events, specificity estimates are potentially misleading for assessing automated detector performance; 3 reporting the performance of spindle detectors exclusively with sensitivity and specificity estimates, as is often seen in the literature, is insufficient; including sensitivity, precision and a more comprehensive statistic such as Matthew’s correlation coefficient, F1-score, or Cohen’s κ is necessary for adequate evaluation; 4 reporting statistics for some reasonable range of decision thresholds provides a much more complete and useful benchmarking; 5 performance differences between tested automated detectors were found to be similar to those between available expert scorings; 6 much more development is needed to effectively compare the performance of spindle detectors developed by different research teams. Finally, this work clarifies a long-standing but only seldom posed question regarding whether expert scoring truly is a reliable gold standard for sleep spindle assessment.

Multivariate max-stable spatial processes

KAUST Repository

Genton, Marc G.; Padoan, S. A.; Sang, H.

2015-01-01

Max-stable processes allow the spatial dependence of extremes to be modelled and quantified, so they are widely adopted in applications. For a better understanding of extremes, it may be useful to study several variables simultaneously. To this end, we study the maxima of independent replicates of multivariate processes, both in the Gaussian and Student-t cases. We define a Poisson process construction and introduce multivariate versions of the Smith Gaussian extreme-value, the Schlather extremal-Gaussian and extremal-t, and the Brown–Resnick models. We develop inference for the models based on composite likelihoods. We present results of Monte Carlo simulations and an application to daily maximum wind speed and wind gust.

Multivariate max-stable spatial processes

KAUST Repository

Genton, Marc G.

2015-02-11

Max-stable processes allow the spatial dependence of extremes to be modelled and quantified, so they are widely adopted in applications. For a better understanding of extremes, it may be useful to study several variables simultaneously. To this end, we study the maxima of independent replicates of multivariate processes, both in the Gaussian and Student-t cases. We define a Poisson process construction and introduce multivariate versions of the Smith Gaussian extreme-value, the Schlather extremal-Gaussian and extremal-t, and the Brown–Resnick models. We develop inference for the models based on composite likelihoods. We present results of Monte Carlo simulations and an application to daily maximum wind speed and wind gust.

Sleep spindles may predict response to cognitive-behavioral therapy for chronic insomnia.

Science.gov (United States)

Dang-Vu, Thien Thanh; Hatch, Benjamin; Salimi, Ali; Mograss, Melodee; Boucetta, Soufiane; O'Byrne, Jordan; Brandewinder, Marie; Berthomier, Christian; Gouin, Jean-Philippe

2017-11-01

While cognitive-behavioral therapy for insomnia constitutes the first-line treatment for chronic insomnia, only few reports have investigated how sleep architecture relates to response to this treatment. In this pilot study, we aimed to determine whether pre-treatment sleep spindle density predicts treatment response to cognitive-behavioral therapy for insomnia. Twenty-four participants with chronic primary insomnia participated in a 6-week cognitive-behavioral therapy for insomnia performed in groups of 4-6 participants. Treatment response was assessed using the Pittsburgh Sleep Quality Index and the Insomnia Severity Index measured at pre- and post-treatment, and at 3- and 12-months' follow-up assessments. Secondary outcome measures were extracted from sleep diaries over 7 days and overnight polysomnography, obtained at pre- and post-treatment. Spindle density during stage N2-N3 sleep was extracted from polysomnography at pre-treatment. Hierarchical linear modeling analysis assessed whether sleep spindle density predicted response to cognitive-behavioral therapy. After adjusting for age, sex, and education level, lower spindle density at pre-treatment predicted poorer response over the 12-month follow-up, as reflected by a smaller reduction in Pittsburgh Sleep Quality Index over time. Reduced spindle density also predicted lower improvements in sleep diary sleep efficiency and wake after sleep onset immediately after treatment. There were no significant associations between spindle density and changes in the Insomnia Severity Index or polysomnography variables over time. These preliminary results suggest that inter-individual differences in sleep spindle density in insomnia may represent an endogenous biomarker predicting responsiveness to cognitive-behavioral therapy. Insomnia with altered spindle activity might constitute an insomnia subtype characterized by a neurophysiological vulnerability to sleep disruption associated with impaired responsiveness to

Spindle-cell carcinoma of esophagus: a case report

International Nuclear Information System (INIS)

Kim, Ji Chang; Lee, Jae Mun; Jung, Seung Eun; Lee, Kyo Young; Hahn, Seong Tai; Kim, Man Deuk

2001-01-01

Spindle-cell carcinoma of the esophagus is a rare malignant tumor composed of both carcinomatous and sarcomatous elements, and has generated many terminology problems. It is characterized by a bulky polypoid intraluminal mass with a lobulated surface located in the middle third of the esophagus. Local expansion of this organ is observed. The lesion may be pedunculated but despite its bulk, causes little obstruction. We report the imaging findings of a case of spindle-cell carcinoma arising in the upper esophagus

High-Speed Computation of the Kleene Star in Max-Plus Algebraic System Using a Cell Broadband Engine

Science.gov (United States)

Goto, Hiroyuki

This research addresses a high-speed computation method for the Kleene star of the weighted adjacency matrix in a max-plus algebraic system. We focus on systems whose precedence constraints are represented by a directed acyclic graph and implement it on a Cell Broadband Engine™ (CBE) processor. Since the resulting matrix gives the longest travel times between two adjacent nodes, it is often utilized in scheduling problem solvers for a class of discrete event systems. This research, in particular, attempts to achieve a speedup by using two approaches: parallelization and SIMDization (Single Instruction, Multiple Data), both of which can be accomplished by a CBE processor. The former refers to a parallel computation using multiple cores, while the latter is a method whereby multiple elements are computed by a single instruction. Using the implementation on a Sony PlayStation 3™ equipped with a CBE processor, we found that the SIMDization is effective regardless of the system's size and the number of processor cores used. We also found that the scalability of using multiple cores is remarkable especially for systems with a large number of nodes. In a numerical experiment where the number of nodes is 2000, we achieved a speedup of 20 times compared with the method without the above techniques.

Topographic and sex-related differences in sleep spindles in major depressive disorder: a high-density EEG investigation.

Science.gov (United States)

Plante, D T; Goldstein, M R; Landsness, E C; Peterson, M J; Riedner, B A; Ferrarelli, F; Wanger, T; Guokas, J J; Tononi, G; Benca, R M

2013-03-20

Sleep spindles are believed to mediate several sleep-related functions including maintaining disconnection from the external environment during sleep, cortical development, and sleep-dependent memory consolidation. Prior studies that have examined sleep spindles in major depressive disorder (MDD) have not demonstrated consistent differences relative to control subjects, which may be due to sex-related variation and limited spatial resolution of spindle detection. Thus, this study sought to characterize sleep spindles in MDD using high-density electroencephalography (hdEEG) to examine the topography of sleep spindles across the cortex in MDD, as well as sex-related variation in spindle topography in the disorder. All-night hdEEG recordings were collected in 30 unipolar MDD participants (19 women) and 30 age and sex-matched controls. Topography of sleep spindle density, amplitude, duration, and integrated spindle activity (ISA) were assessed to determine group differences. Spindle parameters were compared between MDD and controls, including analysis stratified by sex. As a group, MDD subjects demonstrated significant increases in frontal and parietal spindle density and ISA compared to controls. When stratified by sex, MDD women demonstrated increases in frontal and parietal spindle density, amplitude, duration, and ISA; whereas MDD men demonstrated either no differences or decreases in spindle parameters. Given the number of male subjects, this study may be underpowered to detect differences in spindle parameters in male MDD participants. This study demonstrates topographic and sex-related differences in sleep spindles in MDD. Further research is warranted to investigate the role of sleep spindles and sex in the pathophysiology of MDD. Copyright © 2012 Elsevier B.V. All rights reserved.

On the Free Vibration Modeling of Spindle Systems: A Calibrated Dynamic Stiffness Matrix

Directory of Open Access Journals (Sweden)

Omar Gaber

2014-01-01

Full Text Available The effect of bearings on the vibrational behavior of machine tool spindles is investigated. This is done through the development of a calibrated dynamic stiffness matrix (CDSM method, where the bearings flexibility is represented by massless linear spring elements with tuneable stiffness. A dedicated MATLAB code is written to develop and to assemble the element stiffness matrices for the system’s multiple components and to apply the boundary conditions. The developed method is applied to an illustrative example of spindle system. When the spindle bearings are modeled as simply supported boundary conditions, the DSM model results in a fundamental frequency much higher than the system’s nominal value. The simply supported boundary conditions are then replaced by linear spring elements, and the spring constants are adjusted such that the resulting calibrated CDSM model leads to the nominal fundamental frequency of the spindle system. The spindle frequency results are also validated against the experimental data. The proposed method can be effectively applied to predict the vibration characteristics of spindle systems supported by bearings.

Breast spindle cell tumours: about eight cases

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Abd El All Howayda S

2006-07-01

Full Text Available Abstract Background Breast spindle cell tumours (BSCTs, although rare, represent a heterogeneous group with different treatment modalities. This work was undertaken to evaluate the utility of fine needle aspiration cytology (FNAC, histopathology and immunohistochemistry (IHC in differentiating BSCTs. Methods FNAC of eight breast masses diagnosed cytologically as BSCTs was followed by wide excision biopsy. IHC using a panel of antibodies against vimentin, pan-cytokeratin, s100, desmin, smooth muscle actin, CD34, and CD10 was evaluated to define their nature. Results FNAC defined the tumors as benign (n = 4, suspicious (n = 2 and malignant (n = 3, based on the cytopathological criteria of malignancy. Following wide excision biopsy, the tumors were reclassified into benign (n = 5 and malignant (n = 3. In the benign group, the diagnosis was raised histologically and confirmed by IHC for 3 cases (one spindle cell lipoma, one myofibroblastoma and one leiomyoma. For the remaining two cases, the diagnosis was set up after IHC (one fibromatosis and one spindle cell variant of adenomyoepithelioma. In the malignant group, a leiomyosarcoma was diagnosed histologically, while IHC was crucial to set up the diagnosis of one case of spindle cell carcinoma and one malignant myoepithelioma. Conclusion FNAC in BSCTs is an insufficient tool and should be followed by wide excision biopsy. The latter technique differentiate benign from malignant BSCTs and is able in 50% of the cases to set up the definite diagnosis. IHC is of value to define the nature of different benign lesions and is mandatory in the malignant ones for optimal treatment. Awareness of the different types of BSCTs prevents unnecessary extensive therapeutic regimes.

Comparison of a Four-Section Spindle and Stomacher for Efficacy of Detaching Microorganisms from Fresh Vegetables.

Science.gov (United States)

Kim, Do-Kyun; Kim, Soo-Ji; Kang, Dong-Hyun

2015-07-01

This study was undertaken to compare the effect of the spindle and stomacher for detaching microorganisms from fresh vegetables. The spindle is an apparatus for detaching microorganisms from food surfaces, which was developed in our laboratory. When processed with the spindle, food samples were barely disrupted, the original shape was maintained, and the diluent was clear, facilitating further detection analysis more easily than with stomacher treatment. The four-section spindle consists of four sample bag containers (A, B, C, and D) to economize time and effort by simultaneously processing four samples. The aerobic plate counts (APC) of 50 fresh vegetable samples were measured following spindle and stomacher treatment. Correlations between the two methods for each section of the spindle and stomacher were very high (R(2) = 0.9828 [spindle compartment A; Sp A], 0.9855 [Sp B], 0.9848 [Sp C], and 0.9851 [Sp D]). One-tenth milliliter of foodborne pathogens suspensions was inoculated onto surfaces of food samples, and ratios of spindle-to-stomacher enumerations were close to 1.00 log CFU/g between every section of the spindle and stomacher. One of the greatest features of the spindle is that it can treat large-sized samples that exceed 200 g. Uncut whole apples, green peppers, potatoes, and tomatoes were processed by the spindle and by hand massaging by 2 min. Large-sized samples were also assayed for aerobic plate count and recovery of the three foodborne pathogens, and the difference between each section of the spindle and hand massaging was not significant (P > 0.05). This study demonstrated that the spindle apparatus can be an alternative device for detaching microorganisms from all fresh vegetable samples for microbiological analysis by the food processing industry.

Age-related Changes In Sleep Spindles Characteristics During Daytime Recovery Following a 25-Hour Sleep Deprivation

Directory of Open Access Journals (Sweden)

Thaïna eRosinvil

2015-06-01

Full Text Available Objectives: The mechanisms underlying sleep spindles (~11-15Hz; >0.5s help to protect sleep. With age, it becomes increasingly difficult to maintain sleep at a challenging time (e.g. daytime, even after sleep loss. This study compared spindle characteristics during daytime recovery and nocturnal sleep in young and middle-aged adults. In addition, we explored whether spindles characteristics in baseline nocturnal sleep were associated with the ability to maintain sleep during daytime recovery periods in both age groups.Methods: Twenty-nine young (15 women and 14 men; 27.3 ± 5.0 and 31 middle-aged (19 women and 13 men; 51.6 y ± 5.1 healthy subjects participated in a baseline nocturnal sleep and a daytime recovery sleep after 25 hours of sleep deprivation. Spindles were detected on artefact-free NREM sleep epochs. Spindle density (nb/min, amplitude (μV, frequency (Hz and duration (s were analyzed on parasagittal (linked-ears derivations. Results: In young subjects, spindle frequency increased during daytime recovery sleep as compared to baseline nocturnal sleep in all derivations, whereas middle-aged subjects showed spindle frequency enhancement only in the prefrontal derivation. No other significant interaction between age group and sleep condition was observed. Spindle density for all derivations and centro-occipital spindle amplitude decreased whereas prefrontal spindle amplitude increased from baseline to daytime recovery sleep in both age groups. Finally, no significant correlation was found between spindle characteristics during baseline nocturnal sleep and the marked reduction in sleep efficiency during daytime recovery sleep in both young and middle-aged subjects.Conclusion: These results suggest that the interaction between homeostatic and circadian pressure module spindle frequency differently in aging. Spindle characteristics do not seem to be linked with the ability to maintain daytime recovery sleep.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

OpenAIRE

Dhandapani, N. V.; Thangarasu, V. S.; Sureshkannan, G.

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the...

Vibration sensitivity of human muscle spindles and Golgi tendon organs.

Science.gov (United States)

Fallon, James B; Macefield, Vaughan G

2007-07-01

The responses of the various muscle receptors to vibration are more complicated than a naïve categorization into stretch (muscle spindle primary ending), length (muscle spindle secondary endings), and tension (Golgi tendon organs) receptors. To emphasize the similarity of responses to small length changes, we recorded from 58 individual muscle afferents subserving receptors in the ankle or toe dorsiflexors of awake human subjects (32 primary endings, 20 secondary endings, and six Golgi tendon organs). Transverse sinusoidal vibration was applied to the distal tendon of the receptor-bearing muscle, while subjects either remained completely relaxed or maintained a weak isometric contraction of the appropriate muscle. In relaxed muscle, few units responded in a 1:1 manner to vibration, and there was no evidence of a preferred frequency of activation. In active muscle the response profiles of all three receptor types overlapped, with no significant difference in threshold between receptor types. These results emphasize that when intramuscular tension increases during a voluntary contraction, Golgi tendon organs and muscle spindle secondary endings, not just muscle spindle primary endings, can effectively encode small imposed length changes.

REM sleep behaviour disorder is associated with lower fast and higher slow sleep spindle densities.

Science.gov (United States)

O'Reilly, Christian; Godin, Isabelle; Montplaisir, Jacques; Nielsen, Tore

2015-12-01

To investigate differences in sleep spindle properties and scalp topography between patients with rapid eye movement sleep behaviour disorder (RBD) and healthy controls, whole-night polysomnograms of 35 patients diagnosed with RBD and 35 healthy control subjects matched for age and sex were compared. Recordings included a 19-lead 10-20 electroencephalogram montage and standard electromyogram, electrooculogram, electrocardiogram and respiratory leads. Sleep spindles were automatically detected using a standard algorithm, and their characteristics (amplitude, duration, density, frequency and frequency slope) compared between groups. Topological analyses of group-discriminative features were conducted. Sleep spindles occurred at a significantly (e.g. t34 = -4.49; P = 0.00008 for C3) lower density (spindles ∙ min(-1) ) for RBD (mean ± SD: 1.61 ± 0.56 for C3) than for control (2.19 ± 0.61 for C3) participants. However, when distinguishing slow and fast spindles using thresholds individually adapted to the electroencephalogram spectrum of each participant, densities smaller (31-96%) for fast but larger (20-120%) for slow spindles were observed in RBD in all derivations. Maximal differences were in more posterior regions for slow spindles, but over the entire scalp for fast spindles. Results suggest that the density of sleep spindles is altered in patients with RBD and should therefore be investigated as a potential marker of future neurodegeneration in these patients. © 2015 European Sleep Research Society.

Expert and crowd-sourced validation of an individualized sleep spindle detection method employing complex demodulation and individualized normalization

Directory of Open Access Journals (Sweden)

Laura eRay

2015-09-01

Full Text Available A spindle detection method was developed that: 1 extracts the signal of interest (i.e., spindle-related phasic changes in sigma relative to ongoing background sigma activity using complex demodulation, 2 accounts for variations of spindle characteristics across the night, scalp derivations and between individuals, and 3 employs a minimum number of sometimes arbitrary, user-defined parameters. Complex demodulation was used to extract instantaneous power in the spindle band. To account for intra- and inter-individual differences, the signal was z-score transformed using a 60s sliding window, per channel, over the course of the recording. Spindle events were detected with a z-score threshold corresponding to a low probability (e.g., 99th percentile. Spindle characteristics, such as amplitude, duration and oscillatory frequency, were derived for each individual spindle following detection, which permits spindles to be subsequently and flexibly categorized as slow or fast spindles from a single detection pass. Spindles were automatically detected in 15 young healthy subjects. Two experts manually identified spindles from C3 during Stage 2 sleep, from each recording; one employing conventional guidelines, and the other, identifying spindles with the aid of a sigma (11-16 Hz filtered channel. These spindles were then compared between raters and to the automated detection to identify the presence of true positives, true negatives, false positives and false negatives. This method of automated spindle detection resolves or avoids many of the limitations that complicate automated spindle detection, and performs well compared to a group of non-experts, and importantly, has good external validity with respect to the extant literature in terms of the characteristics of automatically detected spindles.

Spindle formation in the mouse embryo requires Plk4 in the absence of centrioles.

Science.gov (United States)

Coelho, Paula A; Bury, Leah; Sharif, Bedra; Riparbelli, Maria G; Fu, Jingyan; Callaini, Giuliano; Glover, David M; Zernicka-Goetz, Magdalena

2013-12-09

During the first five rounds of cell division in the mouse embryo, spindles assemble in the absence of centrioles. Spindle formation initiates around chromosomes, but the microtubule nucleating process remains unclear. Here we demonstrate that Plk4, a protein kinase known as a master regulator of centriole formation, is also essential for spindle assembly in the absence of centrioles. Depletion of maternal Plk4 prevents nucleation and growth of microtubules and results in monopolar spindle formation. This leads to cytokinesis failure and, consequently, developmental arrest. We show that Plk4 function depends on its kinase activity and its partner protein, Cep152. Moreover, tethering Cep152 to cellular membranes sequesters Plk4 and is sufficient to trigger spindle assembly from ectopic membranous sites. Thus, the Plk4-Cep152 complex has an unexpected role in promoting microtubule nucleation in the vicinity of chromosomes to mediate bipolar spindle formation in the absence of centrioles. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

PENGEMBANGAN PERSAMAAN VO2 MAX DAN EVALUASI HR MAX (STUDI AWAL PADA PEKERJA PRIA

Directory of Open Access Journals (Sweden)

Purnawan Adi Wicaksono

2012-10-01

Full Text Available Kapasitas fisik maksimum seseorang direpresentasikan dengan nilai konsumsi oksigen maksimum (VO2 Max dan denyut nadi maksimum (HR Max yang memberikan suatu informasi batasan kemampuan fisik maksimum seseorang dalam melakukan pekerjaan. Penelitian kali ini mempunyai tujuan untuk mencari nilai VO2 Max pekerja pria Indonesia untuk nantinya akan dikembangkan suatu persamaan prediksi VO2 Max yang didekati dengan hubungan linier antara denyut nadi (Heart Rate seperti yang dilakukan Astrand (2003, tinggi badan (Chatterjee et al, 2006, berat badan (Akalan et al, 2008, usia (Magrani et al, 2009 dan mengevaluasi persamaan HR Max manakah yang dapat diaplikasikan untuk mendekati nilai denyut nadi maksimum pekerja Indonesia. Responden dalam penelitian kali ini adalah 12  pekerja industri pria yang diambil dari beberapa industri di Depok dan sekitarnya. Kriteria responden yang berpartisipasi dalam penelitian kali ini adalah: berusia 20-40 tahun, bukan perokok baik aktif maupun pasif, sehat , tidak mengkonsumsi makanan, kafein, alkohol minimal 2 jam sebelum eksperimen (Balderrama et. al, 2007.Eksperimen yang dilakukan menggunakan metode maximal test dengan protokol treadmill. Adapun peralatan yang digunakan adalah seperangkat alat pengukur kondisi fisiologi Fitmate MED (COSMED srl-Italy terdiri dari Heart Rate Transmitter, Heart Rate Receiver, V mask (Hans Rudolph Inc,dan treadmill SportArt@60.  Eksperimen dilakukan menjadi dua bagian, yaitu istirahat dan tahap bekerja.Aktivitas istirahat terdiri dari tidur selama 20 menit, duduk selama 20 menit dan berdiri selama 10 menit. Eksperimen tahap kedua yaitu tahap kerja yang terdiri dari latihan selama 5 menit. Responden dipersilakan beristirahat selama 15 menit, setelah itu responden melaksanakan maximal test detik hingga responden merasa tidak sanggup lagi melanjutkan eksperimen. Hasil penelitian model prediksi VO2 max untuk pekerja industri pria mempunyai nilai 2,78 ± 0,5 liter/menit dan dengan regresi linier

Different maturational changes of fast and slow sleep spindles in the first four years of life.

Science.gov (United States)

D'Atri, Aurora; Novelli, Luana; Ferrara, Michele; Bruni, Oliviero; De Gennaro, Luigi

2018-02-01

Massive changes in brain morphology and function in the first years of life reveal a postero-anterior trajectory of cortical maturation accompanied by regional modifications of NREM sleep. One of the most sensible marker of this maturation process is represented by electroencephalographic (EEG) activity within the frequency range of sleep spindles. However, direct evidence that these changes actually reflect maturational modifications of fast and slow spindles still lacks. Our study aimed at answering the following questions: 1. Do cortical changes at 11.50 Hz frequency correspond to slow spindles? 2. Do fast and slow spindles show different age trajectories and different topographical distributions? 3. Do changes in peak frequency explain age changes of slow and fast spindles? We measured the antero-posterior changes of slow and fast spindles in the first 60 min of nightly sleep of 39 infants and children (0-48 mo.). We found that (A) changes of slow spindles from birth to childhood mostly affect frontal areas (B) variations of fast and slow spindles across age groups go in opposite direction, the latter progressively increasing across ages; (C) this process is not merely reducible to changes of spindle frequency. As a main finding, our cross-sectional study shows that the first form of mature spindle (i.e., corresponding to the adult phasic event of NREM sleep) is marked by the emergence of slow spindles on anterior regions around the age of 12 months. Copyright © 2017 Elsevier B.V. All rights reserved.

A Hybrid Shared-Memory Parallel Max-Tree Algorithm for Extreme Dynamic-Range Images.

Science.gov (United States)

Moschini, Ugo; Meijster, Arnold; Wilkinson, Michael H F

2018-03-01

Max-trees, or component trees, are graph structures that represent the connected components of an image in a hierarchical way. Nowadays, many application fields rely on images with high-dynamic range or floating point values. Efficient sequential algorithms exist to build trees and compute attributes for images of any bit depth. However, we show that the current parallel algorithms perform poorly already with integers at bit depths higher than 16 bits per pixel. We propose a parallel method combining the two worlds of flooding and merging max-tree algorithms. First, a pilot max-tree of a quantized version of the image is built in parallel using a flooding method. Later, this structure is used in a parallel leaf-to-root approach to compute efficiently the final max-tree and to drive the merging of the sub-trees computed by the threads. We present an analysis of the performance both on simulated and actual 2D images and 3D volumes. Execution times are about better than the fastest sequential algorithm and speed-up goes up to on 64 threads.

Slow sleep spindle and procedural memory consolidation in patients with major depressive disorder

Directory of Open Access Journals (Sweden)

Nishida M

2016-01-01

Full Text Available Masaki Nishida,1 Yusaku Nakashima,2 Toru Nishikawa11Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo, 2Medical Technology Research Laboratory, Research and Development Division, Medical Business Unit, Sony Corporation, Tokyo, JapanIntroduction: Evidence has accumulated, which indicates that, in healthy individuals, sleep enhances procedural memory consolidation, and that sleep spindle activity modulates this process. However, whether sleep-dependent procedural memory consolidation occurs in patients medicated for major depressive disorder remains unclear, as are the pharmacological and physiological mechanisms that underlie this process.Methods: Healthy control participants (n=17 and patients medicated for major depressive disorder (n=11 were recruited and subjected to a finger-tapping motor sequence test (MST; nondominant hand paradigm to compare the averaged scores of different learning phases (presleep, postsleep, and overnight improvement. Participants' brain activity was recorded during sleep with 16 electroencephalography channels (between MSTs. Sleep scoring and frequency analyses were performed on the electroencephalography data. Additionally, we evaluated sleep spindle activity, which divided the spindles into fast-frequency spindle activity (12.5–16 Hz and slow-frequency spindle activity (10.5–12.5 Hz.Result: Sleep-dependent motor memory consolidation in patients with depression was impaired in comparison with that in control participants. In patients with depression, age correlated negatively with overnight improvement. The duration of slow-wave sleep correlated with the magnitude of motor memory consolidation in patients with depression, but not in healthy controls. Slow-frequency spindle activity was associated with reduction in the magnitude of motor memory consolidation in both groups.Conclusion: Because the changes in slow

Valve spindle gland

International Nuclear Information System (INIS)

Burda, Z.; Harazim, A.; Kerlin, K.

1979-01-01

A gland is proposed of the valve spindle designed for radioactive or otherwise harmful media, such as in nuclear power plant primary circuits. The gland is installed in the valve cover and consists of a primary and a secondary part and of a gland case partitioning the gland space into two chambers. The bottom face of the gland case is provided with a double-sided collar for controlling the elements of the bottom primary gland while the top face is provided with a removable flange. (M.S.)

On the Dynamics of Rocking Motion of the Hard-Disk Drive Spindle Motor System

Science.gov (United States)

Wang, Joseph

Excessive rocking motion of the spindle motor system can cause track misregistration resulting in poor throughput or even drive failure. The chance of excessive disk stack rocking increases as a result of decreasing torsional stiffness of spindle motor bearing system due to the market demand for low profile hard drives. As the track density increases and the vibration specification becomes increasingly stringent, rocking motion of a spindle motor system deserves even more attention and has become a primary challenge for a spindle motor system designer. Lack of understanding of the rocking phenomenon combined with misleading paradox has presented a great difficulty in the effort of avoiding the rocking motion in the hard-disk drive industry. This paper aims to provide fundamental understanding of the rocking phenomenon of a rotating spindle motor system, to clarify the paradox in disk-drive industry and to provide a design guide to an optimized spindle system. This paper, theoretically and experimentally, covers a few important areas of industrial interest including the prediction of rocking natural frequencies and mode shape of a rotating spindle, free vibration, and frequency response under common forcing functions such as rotating and fixed-plane forcing functions. The theory presented here meets with agreeable experimental observation.

A Bipolar Spindle of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation

DEFF Research Database (Denmark)

Gayathri, P; Fujii, T; Møller-Jensen, Jakob

2012-01-01

the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture...... of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters toward the poles....

Kinesin-8 effects on mitotic microtubule dynamics contribute to spindle function in fission yeast

Science.gov (United States)

Gergely, Zachary R.; Crapo, Ammon; Hough, Loren E.; McIntosh, J. Richard; Betterton, Meredith D.

2016-01-01

Kinesin-8 motor proteins destabilize microtubules. Their absence during cell division is associated with disorganized mitotic chromosome movements and chromosome loss. Despite recent work studying effects of kinesin-8s on microtubule dynamics, it remains unclear whether the kinesin-8 mitotic phenotypes are consequences of their effect on microtubule dynamics, their well-established motor activity, or additional, unknown functions. To better understand the role of kinesin-8 proteins in mitosis, we studied the effects of deletion of the fission yeast kinesin-8 proteins Klp5 and Klp6 on chromosome movements and spindle length dynamics. Aberrant microtubule-driven kinetochore pushing movements and tripolar mitotic spindles occurred in cells lacking Klp5 but not Klp6. Kinesin-8–deletion strains showed large fluctuations in metaphase spindle length, suggesting a disruption of spindle length stabilization. Comparison of our results from light microscopy with a mathematical model suggests that kinesin-8–induced effects on microtubule dynamics, kinetochore attachment stability, and sliding force in the spindle can explain the aberrant chromosome movements and spindle length fluctuations seen. PMID:27146110

Afferent Innervation, Muscle Spindles, and Contractures Following Neonatal Brachial Plexus Injury in a Mouse Model.

Science.gov (United States)

Nikolaou, Sia; Hu, Liangjun; Cornwall, Roger

2015-10-01

We used an established mouse model of elbow flexion contracture after neonatal brachial plexus injury (NBPI) to test the hypothesis that preservation of afferent innervation protects against contractures and is associated with preservation of muscle spindles and ErbB signaling. A model of preganglionic C5 through C7 NBPI was first tested in mice with fluorescent axons using confocal imaging to confirm preserved afferent innervation of spindles despite motor end plate denervation. Preganglionic and postganglionic injuries were then created in wild-type mice. Four weeks later, we assessed total and afferent denervation of the elbow flexors by musculocutaneous nerve immunohistochemistry. Biceps muscle volume and cross-sectional area were measured by micro computed tomography. An observer who was blinded to the study protocol measured elbow flexion contractures. Biceps spindle and muscle fiber morphology and ErbB signaling pathway activity were assessed histologically and immunohistochemically. Preganglionic and postganglionic injuries caused similar total denervation and biceps muscle atrophy. However, after preganglionic injuries, afferent innervation was partially preserved and elbow flexion contractures were significantly less severe. Spindles degenerated after postganglionic injury but were preserved after preganglionic injury. ErbB signaling was inactivated in denervated spindles after postganglionic injury but ErbB signaling activity was preserved in spindles after preganglionic injury with retained afferent innervation. Preganglionic and postganglionic injuries were associated with upregulation of ErbB signaling in extrafusal muscle fibers. Contractures after NBPI are associated with muscle spindle degeneration and loss of spindle ErbB signaling activity. Preservation of afferent innervation maintained spindle development and ErbB signaling activity, and protected against contractures. Pharmacologic modulation of ErbB signaling, which is being investigated as a

Sleep Spindle Characteristics in Children with Neurodevelopmental Disorders and Their Relation to Cognition

Science.gov (United States)

Wise, Merrill S.

2016-01-01

Empirical evidence indicates that sleep spindles facilitate neuroplasticity and “off-line” processing during sleep, which supports learning, memory consolidation, and intellectual performance. Children with neurodevelopmental disorders (NDDs) exhibit characteristics that may increase both the risk for and vulnerability to abnormal spindle generation. Despite the high prevalence of sleep problems and cognitive deficits in children with NDD, only a few studies have examined the putative association between spindle characteristics and cognitive function. This paper reviews the literature regarding sleep spindle characteristics in children with NDD and their relation to cognition in light of what is known in typically developing children and based on the available evidence regarding children with NDD. We integrate available data, identify gaps in understanding, and recommend future research directions. Collectively, studies are limited by small sample sizes, heterogeneous populations with multiple comorbidities, and nonstandardized methods for collecting and analyzing findings. These limitations notwithstanding, the evidence suggests that future studies should examine associations between sleep spindle characteristics and cognitive function in children with and without NDD, and preliminary findings raise the intriguing question of whether enhancement or manipulation of sleep spindles could improve sleep-dependent memory and other aspects of cognitive function in this population. PMID:27478646

Fabrication of an infrared Shack-Hartmann sensor by combining high-speed single-point diamond milling and precision compression molding processes.

Science.gov (United States)

Zhang, Lin; Zhou, Wenchen; Naples, Neil J; Yi, Allen Y

2018-05-01

A novel fabrication method by combining high-speed single-point diamond milling and precision compression molding processes for fabrication of discontinuous freeform microlens arrays was proposed. Compared with slow tool servo diamond broaching, high-speed single-point diamond milling was selected for its flexibility in the fabrication of true 3D optical surfaces with discontinuous features. The advantage of single-point diamond milling is that the surface features can be constructed sequentially by spacing the axes of a virtual spindle at arbitrary positions based on the combination of rotational and translational motions of both the high-speed spindle and linear slides. By employing this method, each micro-lenslet was regarded as a microstructure cell by passing the axis of the virtual spindle through the vertex of each cell. An optimization arithmetic based on minimum-area fabrication was introduced to the machining process to further increase the machining efficiency. After the mold insert was machined, it was employed to replicate the microlens array onto chalcogenide glass. In the ensuing optical measurement, the self-built Shack-Hartmann wavefront sensor was proven to be accurate in detecting an infrared wavefront by both experiments and numerical simulation. The combined results showed that precision compression molding of chalcogenide glasses could be an economic and precision optical fabrication technology for high-volume production of infrared optics.

Sequential activities of Dynein, Mud and Asp in centrosome-spindle coupling maintain centrosome number upon mitosis.

Science.gov (United States)

Bosveld, Floris; Ainslie, Anna; Bellaïche, Yohanns

2017-10-15

Centrosomes nucleate microtubules and are tightly coupled to the bipolar spindle to ensure genome integrity, cell division orientation and centrosome segregation. While the mechanisms of centrosome-dependent microtubule nucleation and bipolar spindle assembly have been the focus of numerous works, less is known about the mechanisms ensuring the centrosome-spindle coupling. The conserved NuMA protein (Mud in Drosophila ) is best known for its role in spindle orientation. Here, we analyzed the role of Mud and two of its interactors, Asp and Dynein, in the regulation of centrosome numbers in Drosophila epithelial cells. We found that Dynein and Mud mainly initiate centrosome-spindle coupling prior to nuclear envelope breakdown (NEB) by promoting correct centrosome positioning or separation, while Asp acts largely independently of Dynein and Mud to maintain centrosome-spindle coupling. Failure in the centrosome-spindle coupling leads to mis-segregation of the two centrosomes into one daughter cell, resulting in cells with supernumerary centrosomes during subsequent divisions. Altogether, we propose that Dynein, Mud and Asp operate sequentially during the cell cycle to ensure efficient centrosome-spindle coupling in mitosis, thereby preventing centrosome mis-segregation to maintain centrosome number. © 2017. Published by The Company of Biologists Ltd.

Establishing Relationship between Process Parameters and Temperature during High Speed End Milling of Soda Lime Glass

Science.gov (United States)

Nasima Bagum, Mst.; Konneh, Mohamed; Yeakub Ali, Mohammad

2018-01-01

In glass machining crack free surface is required in biomedical and optical industry. Ductile mode machining allows materials removal from brittle materials in a ductile manner rather than by brittle fracture. Although end milling is a versatile process, it has not been applied frequently for machining soda lime glass. Soda lime glass is a strain rate and temperature sensitive material; especially around glass transition temperature Tg, ductility increased and strength decreased. Hence, it is envisaged that the generated temperature by high-speed end milling (HSEM) could be brought close to the glass transition temperature, which promote ductile machining. In this research, the objective is to investigate the effect of high speed machining parameters on generated temperature. The cutting parameters were optimized to generate temperature around glass transition temperature of soda lime using response surface methodology (RSM). Result showed that the most influencing process parameter is feed rate followed by spindle speed and depth of cut to generate temperature. Confirmation test showed that combination of spindle speed 30,173 rpm, feed rate 13.2 mm/min and depth of cut 37.68 µm generate 635°C, hence ductile chip removal with machined surface Ra 0.358 µm was possible to achieve.

Spindle Cell Carcinoma of the hypopharynx: a case report

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Dillu Ram Kandel

2018-03-01

Full Text Available Spindle cell carcinoma of hpopharynx is a rare pathology. It is a poorly differentiated variant of squamous cell carcinoma and morphologically resembles sarcoma. This is a disease of old age. It is usually associated with smoking and alcohol abuse. When it is associated with radiation exposure history it behaves more aggressively. Surgery is considered as the main modality of treatment and adjuvant radiotherapy if necessary. Here we present a case of 79 year old male with spindle cell carcinomaof right piriform fossa with 2-month history of progressive dysphasia and hoarseness that has been affecting his ability to speak and swallow with history of weight loss and past history of radiotherapy. So possibility of spindle cell carcinoma of the hypopharynx should beconsidered in an old patient with rapidly developing swelling of the hypopharynx with past history of radiation exposure. As it is a highly aggressive disease it should be treated timely and more aggressively to prolong the survival of the patient.   

Mounting arrangement for the drive system of an air-bearing spindle on a machine tool

Science.gov (United States)

Lunsford, J.S.; Crisp, D.W.; Petrowski, P.L.

1987-12-07

The present invention is directed to a mounting arrangement for the drive system of an air-bearing spindle utilized on a machine tool such as a lathe. The mounting arrangement of the present invention comprises a housing which is secured to the casing of the air bearing in such a manner that the housing position can be selectively adjusted to provide alignment of the air-bearing drive shaft supported by the housing and the air-bearing spindle. Once this alignment is achieved the air between spindle and the drive arrangement is maintained in permanent alignment so as to overcome misalignment problems encountered in the operation of the machine tool between the air-bearing spindle and the shaft utilized for driving the air-bearing spindle.

Analisis Throughput Varian TCP Pada Model Jaringan WiMAX

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Medi Taruk

2016-07-01

Full Text Available Transmission Control Protocol (TCP is a protocol that works at the transport layer of the OSI model. TCP was originally designed more destined for a wired network. However, to meet the need for the development of a very fast network technology based on the needs of the use by the user, it needs further development to the use of TCP on wireless devices. One implementation of a wireless network based on Worldwide Interoperability for Microwave Access (WiMAX network is a model that offers a variety advantage, particularly in terms of access speed. In this case, use NS-2 to see throughput at TCP variants tested, namely TCP-Tahoe, TCP-Reno, TCP-Vegas, and TCP-SACK over WiMAX network model, with few observations scenarios. The first is a look at each of these variants throughput of TCP when only one particular variant of the work in the network. Second observe all variants of TCP throughput at the same time and have the equivalent QoS, but with the possibility of a small congestion based on the capacity of the link is made sufficient. Third observed throughput with multi congestion. In WiMAX network has scheduling services are UGS, rtPS and ertPS using UDP protocol and nrtPS and BE using the TCP Protocol. By using the software network simulator (NS-2 to obtain performance comparison TCP protocol-based services on the WiMAX network with QoS parameters are throughput, packet loss, fairness and time delay.

The spindle assembly checkpoint: More than just keeping track of the spindle.

OpenAIRE

Lawrence, KS; Engebrecht, J

2015-01-01

Genome stability is essential for cell proliferation and survival. Consequently, genome integrity is monitored by two major checkpoints, the DNA damage response (DDR) and the spindle assembly checkpoint (SAC). The DDR monitors DNA lesions in G1, S, and G2 stages of the cell cycle and the SAC ensures proper chromosome segregation in M phase. There have been extensive studies characterizing the roles of these checkpoints in response to the processes for which they are named; however, emerging e...

Evaluating and Improving Automatic Sleep Spindle Detection by Using Multi-Objective Evolutionary Algorithms

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Min-Yin Liu

2017-05-01

Full Text Available Sleep spindles are brief bursts of brain activity in the sigma frequency range (11–16 Hz measured by electroencephalography (EEG mostly during non-rapid eye movement (NREM stage 2 sleep. These oscillations are of great biological and clinical interests because they potentially play an important role in identifying and characterizing the processes of various neurological disorders. Conventionally, sleep spindles are identified by expert sleep clinicians via visual inspection of EEG signals. The process is laborious and the results are inconsistent among different experts. To resolve the problem, numerous computerized methods have been developed to automate the process of sleep spindle identification. Still, the performance of these automated sleep spindle detection methods varies inconsistently from study to study. There are two reasons: (1 the lack of common benchmark databases, and (2 the lack of commonly accepted evaluation metrics. In this study, we focus on tackling the second problem by proposing to evaluate the performance of a spindle detector in a multi-objective optimization context and hypothesize that using the resultant Pareto fronts for deriving evaluation metrics will improve automatic sleep spindle detection. We use a popular multi-objective evolutionary algorithm (MOEA, the Strength Pareto Evolutionary Algorithm (SPEA2, to optimize six existing frequency-based sleep spindle detection algorithms. They include three Fourier, one continuous wavelet transform (CWT, and two Hilbert-Huang transform (HHT based algorithms. We also explore three hybrid approaches. Trained and tested on open-access DREAMS and MASS databases, two new hybrid methods of combining Fourier with HHT algorithms show significant performance improvement with F1-scores of 0.726–0.737.

Automated high-throughput quantification of mitotic spindle positioning from DIC movies of Caenorhabditis embryos.

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David Cluet

Full Text Available The mitotic spindle is a microtubule-based structure that elongates to accurately segregate chromosomes during anaphase. Its position within the cell also dictates the future cell cleavage plan, thereby determining daughter cell orientation within a tissue or cell fate adoption for polarized cells. Therefore, the mitotic spindle ensures at the same time proper cell division and developmental precision. Consequently, spindle dynamics is the matter of intensive research. Among the different cellular models that have been explored, the one-cell stage C. elegans embryo has been an essential and powerful system to dissect the molecular and biophysical basis of spindle elongation and positioning. Indeed, in this large and transparent cell, spindle poles (or centrosomes can be easily detected from simple DIC microscopy by human eyes. To perform quantitative and high-throughput analysis of spindle motion, we developed a computer program ACT for Automated-Centrosome-Tracking from DIC movies of C. elegans embryos. We therefore offer an alternative to the image acquisition and processing of transgenic lines expressing fluorescent spindle markers. Consequently, experiments on large sets of cells can be performed with a simple setup using inexpensive microscopes. Moreover, analysis of any mutant or wild-type backgrounds is accessible because laborious rounds of crosses with transgenic lines become unnecessary. Last, our program allows spindle detection in other nematode species, offering the same quality of DIC images but for which techniques of transgenesis are not accessible. Thus, our program also opens the way towards a quantitative evolutionary approach of spindle dynamics. Overall, our computer program is a unique macro for the image- and movie-processing platform ImageJ. It is user-friendly and freely available under an open-source licence. ACT allows batch-wise analysis of large sets of mitosis events. Within 2 minutes, a single movie is processed

Analysis list: Max [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available Max Blood,Muscle,Pluripotent stem cell + mm9 http://dbarchive.biosciencedbc.jp/kyus...hu-u/mm9/target/Max.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Max.5.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/target/Max.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Max.Blood....tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Max.Muscle.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/colo/Max.Pluripotent_stem_cell.tsv http://dbarchive.biosciencedbc.jp/k

Autocatalytic microtubule nucleation determines the size and mass of Xenopus laevis egg extract spindles.

Science.gov (United States)

Decker, Franziska; Oriola, David; Dalton, Benjamin; Brugués, Jan

2018-01-11

Regulation of size and growth is a fundamental problem in biology. A prominent example is the formation of the mitotic spindle, where protein concentration gradients around chromosomes are thought to regulate spindle growth by controlling microtubule nucleation. Previous evidence suggests that microtubules nucleate throughout the spindle structure. However, the mechanisms underlying microtubule nucleation and its spatial regulation are still unclear. Here, we developed an assay based on laser ablation to directly probe microtubule nucleation events in Xenopus laevis egg extracts. Combining this method with theory and quantitative microscopy, we show that the size of a spindle is controlled by autocatalytic growth of microtubules, driven by microtubule-stimulated microtubule nucleation. The autocatalytic activity of this nucleation system is spatially regulated by the limiting amounts of active microtubule nucleators, which decrease with distance from the chromosomes. This mechanism provides an upper limit to spindle size even when resources are not limiting. © 2018, Decker et al.

A SUMOylation Motif in Aurora-A: Implications for Spindle Dynamics and Oncogenesis

Energy Technology Data Exchange (ETDEWEB)

Pérez de Castro, Ignacio; Aguirre-Portolés, Cristina [Molecular Oncology Programme, Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain); Martin, Benedicte [CNRS-UMR 6061, Institut de Génétique et Développement de Rennes, IFR 140 GFAS, Faculté de Médecine, Université Rennes 1, Rennes (France); Fernández-Miranda, Gonzalo [Molecular Oncology Programme, Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain); Klotzbucher, Andrea; Kubbutat, Michael H. G. [ProQinase GmBH, Freiburg (Germany); Megías, Diego [Confocal Microscopy Core Unit, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain); Arlot-Bonnemains, Yannick [CNRS-UMR 6061, Institut de Génétique et Développement de Rennes, IFR 140 GFAS, Faculté de Médecine, Université Rennes 1, Rennes (France); Malumbres, Marcos, E-mail: mmm@cnio.es, E-mail: iperez@cnio.es [Molecular Oncology Programme, Cell Division and Cancer Group, Centro Nacional de Investigaciones Oncológicas, Madrid (Spain)

2011-12-14

Aurora-A is a serine/threonine kinase that plays critical roles in centrosome maturation, spindle dynamics, and chromosome orientation and it is frequently over-expressed in human cancers. In this work, we show that Aurora-A interacts with the SUMO-conjugating enzyme UBC9 and co-localizes with SUMO1 in mitotic cells. Aurora-A can be SUMOylated in vitro and in vivo. Mutation of the highly conserved SUMOylation residue lysine 249 significantly disrupts Aurora-A SUMOylation and mitotic defects characterized by defective and multipolar spindles ensue. The Aurora-A{sup K249R} mutant has normal kinase activity but displays altered dynamics at the mitotic spindle. In addition, ectopic expression of the Aurora-A{sup K249R} mutant results in a significant increase in susceptibility to malignant transformation induced by the Ras oncogene. These data suggest that modification by SUMO residues may control Aurora-A function at the spindle and that deficiency of SUMOylation of this kinase may have important implications for tumor development.

Cortical dendritic activity correlates with spindle-rich oscillations during sleep in rodents.

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Seibt, Julie; Richard, Clément J; Sigl-Glöckner, Johanna; Takahashi, Naoya; Kaplan, David I; Doron, Guy; de Limoges, Denis; Bocklisch, Christina; Larkum, Matthew E

2017-09-25

How sleep influences brain plasticity is not known. In particular, why certain electroencephalographic (EEG) rhythms are linked to memory consolidation is poorly understood. Calcium activity in dendrites is known to be necessary for structural plasticity changes, but this has never been carefully examined during sleep. Here, we report that calcium activity in populations of neocortical dendrites is increased and synchronised during oscillations in the spindle range in naturally sleeping rodents. Remarkably, the same relationship is not found in cell bodies of the same neurons and throughout the cortical column. Spindles during sleep have been suggested to be important for brain development and plasticity. Our results provide evidence for a physiological link of spindles in the cortex specific to dendrites, the main site of synaptic plasticity.Different stages of sleep, marked by particular electroencephalographic (EEG) signatures, have been linked to memory consolidation, but underlying mechanisms are poorly understood. Here, the authors show that dendritic calcium synchronisation correlates with spindle-rich sleep phases.

Constrained Balancing of Two Industrial Rotor Systems: Least Squares and Min-Max Approaches

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Bin Huang

2009-01-01

Full Text Available Rotor vibrations caused by rotor mass unbalance distributions are a major source of maintenance problems in high-speed rotating machinery. Minimizing this vibration by balancing under practical constraints is quite important to industry. This paper considers balancing of two large industrial rotor systems by constrained least squares and min-max balancing methods. In current industrial practice, the weighted least squares method has been utilized to minimize rotor vibrations for many years. One of its disadvantages is that it cannot guarantee that the maximum value of vibration is below a specified value. To achieve better balancing performance, the min-max balancing method utilizing the Second Order Cone Programming (SOCP with the maximum correction weight constraint, the maximum residual response constraint as well as the weight splitting constraint has been utilized for effective balancing. The min-max balancing method can guarantee a maximum residual vibration value below an optimum value and is shown by simulation to significantly outperform the weighted least squares method.

Clathrin is spindle-associated but not essential for mitosis.

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Joana Borlido

Full Text Available Clathrin is a multimeric protein involved in vesicle coat assembly. Recently clathrin distribution was reported to change during the cell cycle and was found to associate with the mitotic spindle. Here we test whether the recruitment of clathrin to the spindle is indicative of a critical functional contribution to mitosis.Previously a chicken pre-B lymphoma cell line (DKO-R was developed in which the endogenous clathrin heavy chain alleles were replaced with the human clathrin heavy chain under the control of a tetracycline-regulatable promoter. Receptor-mediated and fluid-phase endocytosis were significantly inhibited in this line following clathrin knockout, and we used this to explore the significance of clathrin heavy chain expression for cell cycle progression. We confirmed using confocal microscopy that clathrin colocalised with tubulin at mitotic spindles. Using a propidium iodide flow cytometric assay we found no statistical difference in the cell cycle distribution of the knockout cells versus the wild-type. Additionally, we showed that the ploidy and the recovery kinetics following cell cycle arrest with nocodazole were unchanged by repressing clathrin heavy chain expression.We conclude that the association of clathrin with the mitotic spindle and the contribution of clathrin to endocytosis are evolutionarily conserved. However we find that the contribution of clathrin to mitosis is less robust and dependent on cellular context. In other cell-lines silencing RNA has been used by others to knockdown clathrin expression resulting in an increase in the mitotic index of the cells. We show an effect on the G2/M phase population of clathrin knockdown in HEK293 cells but show that repressing clathrin expression in the DKO-R cell-line has no effect on the size of this population. Consequently this work highlights the need for a more detailed molecular understanding of the recruitment and function of clathrin at the spindle, since the

Sleep Spindles in the Right Hemisphere Support Awareness of Regularities and Reflect Pre-Sleep Activations.

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Yordanova, Juliana; Kolev, Vasil; Bruns, Eike; Kirov, Roumen; Verleger, Rolf

2017-11-01

The present study explored the sleep mechanisms which may support awareness of hidden regularities. Before sleep, 53 participants learned implicitly a lateralized variant of the serial response-time task in order to localize sensorimotor encoding either in the left or right hemisphere and induce implicit regularity representations. Electroencephalographic (EEG) activity was recorded at multiple electrodes during both task performance and sleep, searching for lateralized traces of the preceding activity during learning. Sleep EEG analysis focused on region-specific slow (9-12 Hz) and fast (13-16 Hz) sleep spindles during nonrapid eye movement sleep. Fast spindle activity at those motor regions that were activated during learning increased with the amount of postsleep awareness. Independently of side of learning, spindle activity at right frontal and fronto-central regions was involved: there, fast spindles increased with the transformation of sequence knowledge from implicit before sleep to explicit after sleep, and slow spindles correlated with individual abilities of gaining awareness. These local modulations of sleep spindles corresponded to regions with greater presleep activation in participants with postsleep explicit knowledge. Sleep spindle mechanisms are related to explicit awareness (1) by tracing the activation of motor cortical and right-hemisphere regions which had stronger involvement already during learning and (2) by recruitment of individually consolidated processing modules in the right hemisphere. The integration of different sleep spindle mechanisms with functional states during wake collectively supports the gain of awareness of previously experienced regularities, with a special role for the right hemisphere. © Sleep Research Society 2017. Published by Oxford University Press [on behalf of the Sleep Research Society].

Warts phosphorylates mud to promote pins-mediated mitotic spindle orientation in Drosophila, independent of Yorkie.

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Dewey, Evan B; Sanchez, Desiree; Johnston, Christopher A

2015-11-02

Multicellular animals have evolved conserved signaling pathways that translate cell polarity cues into mitotic spindle positioning to control the orientation of cell division within complex tissue structures. These oriented cell divisions are essential for the development of cell diversity and the maintenance of tissue homeostasis. Despite intense efforts, the molecular mechanisms that control spindle orientation remain incompletely defined. Here, we describe a role for the Hippo (Hpo) kinase complex in promoting Partner of Inscuteable (Pins)-mediated spindle orientation. Knockdown of Hpo, Salvador (Sav), or Warts (Wts) each result in a partial loss of spindle orientation, a phenotype previously described following loss of the Pins-binding protein Mushroom body defect (Mud). Similar to orthologs spanning yeast to mammals, Wts kinase localizes to mitotic spindle poles, a prominent site of Mud localization. Wts directly phosphorylates Mud in vitro within its C-terminal coiled-coil domain. This Mud coiled-coil domain directly binds the adjacent Pins-binding domain to dampen the Pins/Mud interaction, and Wts-mediated phosphorylation uncouples this intramolecular Mud interaction. Loss of Wts prevents cortical Pins/Mud association without affecting Mud accumulation at spindle poles, suggesting phosphorylation acts as a molecular switch to specifically activate cortical Mud function. Finally, loss of Wts in Drosophila imaginal disc epithelial cells results in diminished cortical Mud and defective planar spindle orientation. Our results provide new insights into the molecular basis for dynamic regulation of the cortical Pins/Mud spindle positioning complex and highlight a novel link with an essential, evolutionarily conserved cell proliferation pathway. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fusimotor control of spindle sensitivity regulates central and peripheral coding of joint angles.

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Lan, Ning; He, Xin

2012-01-01

Proprioceptive afferents from muscle spindles encode information about peripheral joint movements for the central nervous system (CNS). The sensitivity of muscle spindle is nonlinearly dependent on the activation of gamma (γ) motoneurons in the spinal cord that receives inputs from the motor cortex. How fusimotor control of spindle sensitivity affects proprioceptive coding of joint position is not clear. Furthermore, what information is carried in the fusimotor signal from the motor cortex to the muscle spindle is largely unknown. In this study, we addressed the issue of communication between the central and peripheral sensorimotor systems using a computational approach based on the virtual arm (VA) model. In simulation experiments within the operational range of joint movements, the gamma static commands (γ(s)) to the spindles of both mono-articular and bi-articular muscles were hypothesized (1) to remain constant, (2) to be modulated with joint angles linearly, and (3) to be modulated with joint angles nonlinearly. Simulation results revealed a nonlinear landscape of Ia afferent with respect to both γ(s) activation and joint angle. Among the three hypotheses, the constant and linear strategies did not yield Ia responses that matched the experimental data, and therefore, were rejected as plausible strategies of spindle sensitivity control. However, if γ(s) commands were quadratically modulated with joint angles, a robust linear relation between Ia afferents and joint angles could be obtained in both mono-articular and bi-articular muscles. With the quadratic strategy of spindle sensitivity control, γ(s) commands may serve as the CNS outputs that inform the periphery of central coding of joint angles. The results suggest that the information of joint angles may be communicated between the CNS and muscles via the descending γ(s) efferent and Ia afferent signals.

Modulation of jaw muscle spindle afferent activity following intramuscular injections with hypertonic saline.

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Ro, J Y; Capra, N F

2001-05-01

Transient noxious chemical stimulation of small diameter muscle afferents modulates jaw movement-related responses of caudal brainstem neurons. While it is likely that the effect is mediated from the spindle afferents in the mesencephalic nucleus (Vmes) via the caudally projecting Probst's tract, the mechanisms of pain induced modulations of jaw muscle spindle afferents is not known. In the present study, we tested the hypothesis that jaw muscle nociceptors gain access to muscle spindle afferents in the same muscle via central mechanisms and alter their sensitivity. Thirty-five neurons recorded from the Vmes were characterized as muscle spindle afferents based on their responses to passive jaw movements, muscle palpation, and electrical stimulation of the masseter nerve. Each cell was tested by injecting a small volume (250 microl) of either 5% hypertonic and/or isotonic saline into the receptor-bearing muscle. Twenty-nine units were tested with 5% hypertonic saline, of which 79% (23/29) showed significant modulation of mean firing rates (MFRs) during one or more phases of ramp-and-hold movements. Among the muscle spindle primary-like units (n = 12), MFRs of 4 units were facilitated, five reduced, two showed mixed responses and one unchanged. In secondary-like units (n = 17), MFRs of 9 were facilitated, three reduced and five unchanged. Thirteen units were tested with isotonic saline, of which 77% showed no significant changes of MFRs. Further analysis revealed that the hypertonic saline not only affected the overall output of muscle spindle afferents, but also increased the variability of firing and altered the relationship between afferent signal and muscle length. These results demonstrated that activation of muscle nociceptors significantly affects proprioceptive properties of jaw muscle spindles via central neural mechanisms. The changes can have deleterious effects on oral motor function as well as kinesthetic sensibility.

Validation of a novel automatic sleep spindle detector with high performance during sleep in middle aged subjects

DEFF Research Database (Denmark)

Wendt, Sabrina Lyngbye; Christensen, Julie A. E.; Kempfner, Jacob

2012-01-01

Many of the automatic sleep spindle detectors currently used to analyze sleep EEG are either validated on young subjects or not validated thoroughly. The purpose of this study is to develop and validate a fast and reliable sleep spindle detector with high performance in middle aged subjects....... An automatic sleep spindle detector using a bandpass filtering approach and a time varying threshold was developed. The validation was done on sleep epochs from EEG recordings with manually scored sleep spindles from 13 healthy subjects with a mean age of 57.9 ± 9.7 years. The sleep spindle detector reached...

Time limit and time at VO2max' during a continuous and an intermittent run.

Science.gov (United States)

Demarie, S; Koralsztein, J P; Billat, V

2000-06-01

The purpose of this study was to verify, by track field tests, whether sub-elite runners (n=15) could (i) reach their VO2max while running at v50%delta, i.e. midway between the speed associated with lactate threshold (vLAT) and that associated with maximal aerobic power (vVO2max), and (ii) if an intermittent exercise provokes a maximal and/or supra maximal oxygen consumption longer than a continuous one. Within three days, subjects underwent a multistage incremental test during which their vVO2max and vLAT were determined; they then performed two additional testing sessions, where continuous and intermittent running exercises at v50%delta were performed up to exhaustion. Subject's gas exchange and heart rate were continuously recorded by means of a telemetric apparatus. Blood samples were taken from fingertip and analysed for blood lactate concentration. In the continuous and the intermittent tests peak VO2 exceeded VO2max values, as determined during the incremental test. However in the intermittent exercise, peak VO2, time to exhaustion and time at VO2max reached significantly higher values, while blood lactate accumulation showed significantly lower values than in the continuous one. The v50%delta is sufficient to stimulate VO2max in both intermittent and continuous running. The intermittent exercise results better than the continuous one in increasing maximal aerobic power, allowing longer time at VO2max and obtaining higher peak VO2 with lower lactate accumulation.

The Drosophila Microtubule-Associated Protein Mars Stabilizes Mitotic Spindles by Crosslinking Microtubules through Its N-Terminal Region

Science.gov (United States)

Zhang, Gang; Beati, Hamze; Nilsson, Jakob; Wodarz, Andreas

2013-01-01

Correct segregation of genetic material relies on proper assembly and maintenance of the mitotic spindle. How the highly dynamic microtubules (MTs) are maintained in stable mitotic spindles is a key question to be answered. Motor and non-motor microtubule associated proteins (MAPs) have been reported to stabilize the dynamic spindle through crosslinking adjacent MTs. Mars, a novel MAP, is essential for the early development of Drosophila embryos. Previous studies showed that Mars is required for maintaining an intact mitotic spindle but did not provide a molecular mechanism for this function. Here we show that Mars is able to stabilize the mitotic spindle in vivo. Both in vivo and in vitro data reveal that the N-terminal region of Mars functions in the stabilization of the mitotic spindle by crosslinking adjacent MTs. PMID:23593258

The Drosophila microtubule-associated protein mars stabilizes mitotic spindles by crosslinking microtubules through its N-terminal region.

Directory of Open Access Journals (Sweden)

Gang Zhang

Full Text Available Correct segregation of genetic material relies on proper assembly and maintenance of the mitotic spindle. How the highly dynamic microtubules (MTs are maintained in stable mitotic spindles is a key question to be answered. Motor and non-motor microtubule associated proteins (MAPs have been reported to stabilize the dynamic spindle through crosslinking adjacent MTs. Mars, a novel MAP, is essential for the early development of Drosophila embryos. Previous studies showed that Mars is required for maintaining an intact mitotic spindle but did not provide a molecular mechanism for this function. Here we show that Mars is able to stabilize the mitotic spindle in vivo. Both in vivo and in vitro data reveal that the N-terminal region of Mars functions in the stabilization of the mitotic spindle by crosslinking adjacent MTs.

The Drosophila microtubule-associated protein mars stabilizes mitotic spindles by crosslinking microtubules through its N-terminal region.

Science.gov (United States)

Zhang, Gang; Beati, Hamze; Nilsson, Jakob; Wodarz, Andreas

2013-01-01

Correct segregation of genetic material relies on proper assembly and maintenance of the mitotic spindle. How the highly dynamic microtubules (MTs) are maintained in stable mitotic spindles is a key question to be answered. Motor and non-motor microtubule associated proteins (MAPs) have been reported to stabilize the dynamic spindle through crosslinking adjacent MTs. Mars, a novel MAP, is essential for the early development of Drosophila embryos. Previous studies showed that Mars is required for maintaining an intact mitotic spindle but did not provide a molecular mechanism for this function. Here we show that Mars is able to stabilize the mitotic spindle in vivo. Both in vivo and in vitro data reveal that the N-terminal region of Mars functions in the stabilization of the mitotic spindle by crosslinking adjacent MTs.

Max Algebraic Complementary Basic Matrices

Czech Academy of Sciences Publication Activity Database

Fiedler, Miroslav; Hall, F.J.

2014-01-01

Roč. 457, 15 September (2014), s. 287-292 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : CB-matrix * Max algebra * Max permanent * Max eigenvalues Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014

Spindle frequency activity in the sleep EEG: individual differences and topographic distribution.

Science.gov (United States)

Werth, E; Achermann, P; Dijk, D J; Borbély, A A

1997-11-01

The brain topography of EEG power spectra in the frequency range of sleep spindles was investigated in 34 sleep recordings from 20 healthy young men. Referential (F3-A2, C3-A2, P3-A2 and O1-A2) and bipolar derivations (F3-C3, C3-P3 and P3-O1) along the anteroposterior axis were used. Sleep spindles gave rise to a distinct peak in the EEG power spectrum. The distribution of the peak frequencies pooled over subjects and derivations showed a bimodal pattern with modes at 11.5 and 13.0 Hz, and a trough at 12.25 Hz. The large inter-subject variation in peak frequency (range: 1.25 Hz) contrasted with the small intra-subject variation between derivations, non-REM sleep episodes and different nights. In some individuals and/or some derivations, only a single spindle peak was present. The topographic distributions from referential and bipolar recordings showed differences. The power showed a declining trend over consecutive non-REM sleep episodes in the low range of spindle frequency activity and a rising trend in the high range. The functional and topographic heterogeneity of sleep spindles in conjunction with the intra-subject stability of their frequency are important characteristics for the analysis of sleep regulation on the basis of the EEG.

Left atrial spindle cell sarcoma – Case report

Directory of Open Access Journals (Sweden)

Nihar Mehta

2012-07-01

Full Text Available Primary spindle cell sarcoma of the left atrium is an extremely rare tumour. Surgical excision is the mainstay of treatment since it responds poorly to chemotherapy or radiotherapy. In spite of all the treatment, the prognosis remains poor due to inadvertent delay in diagnosis, few therapeutic options and propensity to metastasize. We present a 47-year-old male who underwent a surgical excision of a left atrial mass in February 2010. It was proved to be a high-grade spindle cell sarcoma on histopathology. He presented again in October 2010 with recurrence of the tumour for which he was re-operated. However, the tumour recurred again within one month, to which the patient succumbed.

3ds Max design architectural visualization for intermediate users

CERN Document Server

Smith, Brian L

2012-01-01

Learn time-saving techniques and tested production-ready tips for maximum speed and efficiency in creating professional-level architectural visualizations in 3ds Max. Move from intermediate to an advanced level with specific and comprehensive instruction with this collaboration from nine different authors from around the world. Get their experience and skills in this full-color book, which not only teaches more advanced features, but also demonstrates the practical applications of those features to get readers ready for a real production environment. Fully updated for the most recent version o

Sleep-spindle detection: crowdsourcing and evaluating performance of experts, non-experts and automated methods

DEFF Research Database (Denmark)

Warby, Simon C.; Wendt, Sabrina Lyngbye; Welinder, Peter

2014-01-01

to crowdsource spindle identification by human experts and non-experts, and we compared their performance with that of automated detection algorithms in data from middle- to older-aged subjects from the general population. We also refined methods for forming group consensus and evaluating the performance...... of event detectors in physiological data such as electroencephalographic recordings from polysomnography. Compared to the expert group consensus gold standard, the highest performance was by individual experts and the non-expert group consensus, followed by automated spindle detectors. This analysis showed...... that crowdsourcing the scoring of sleep data is an efficient method to collect large data sets, even for difficult tasks such as spindle identification. Further refinements to spindle detection algorithms are needed for middle- to older-aged subjects....

Stage-independent, single lead EEG sleep spindle detection using the continuous wavelet transform and local weighted smoothing.

Science.gov (United States)

Tsanas, Athanasios; Clifford, Gari D

2015-01-01

Sleep spindles are critical in characterizing sleep and have been associated with cognitive function and pathophysiological assessment. Typically, their detection relies on the subjective and time-consuming visual examination of electroencephalogram (EEG) signal(s) by experts, and has led to large inter-rater variability as a result of poor definition of sleep spindle characteristics. Hitherto, many algorithmic spindle detectors inherently make signal stationarity assumptions (e.g., Fourier transform-based approaches) which are inappropriate for EEG signals, and frequently rely on additional information which may not be readily available in many practical settings (e.g., more than one EEG channels, or prior hypnogram assessment). This study proposes a novel signal processing methodology relying solely on a single EEG channel, and provides objective, accurate means toward probabilistically assessing the presence of sleep spindles in EEG signals. We use the intuitively appealing continuous wavelet transform (CWT) with a Morlet basis function, identifying regions of interest where the power of the CWT coefficients corresponding to the frequencies of spindles (11-16 Hz) is large. The potential for assessing the signal segment as a spindle is refined using local weighted smoothing techniques. We evaluate our findings on two databases: the MASS database comprising 19 healthy controls and the DREAMS sleep spindle database comprising eight participants diagnosed with various sleep pathologies. We demonstrate that we can replicate the experts' sleep spindles assessment accurately in both databases (MASS database: sensitivity: 84%, specificity: 90%, false discovery rate 83%, DREAMS database: sensitivity: 76%, specificity: 92%, false discovery rate: 67%), outperforming six competing automatic sleep spindle detection algorithms in terms of correctly replicating the experts' assessment of detected spindles.

Stage-independent, single lead EEG sleep spindle detection using the continuous wavelet transform and local weighted smoothing

Directory of Open Access Journals (Sweden)

Athanasios eTsanas

2015-04-01

Full Text Available Sleep spindles are critical in characterizing sleep and have been associated with cognitive function and pathophysiological assessment. Typically, their detection relies on the subjective and time-consuming visual examination of electroencephalogram (EEG signal(s by experts, and has led to large inter-rater variability as a result of poor definition of sleep spindle characteristics. Hitherto, many algorithmic spindle detectors inherently make signal stationarity assumptions (e.g. Fourier transform-based approaches which are inappropriate for EEG signals, and frequently rely on additional information which may not be readily available in many practical settings (e.g. more than one EEG channels, or prior hypnogram assessment. This study proposes a novel signal processing methodology relying solely on a single EEG channel, and provides objective, accurate means towards probabilistically assessing the presence of sleep spindles in EEG signals. We use the intuitively appealing continuous wavelet transform (CWT with a Morlet basis function, identifying regions of interest where the power of the CWT coefficients corresponding to the frequencies of spindles (11-16 Hz is large. The potential for assessing the signal segment as a spindle is refined using local weighted smoothing techniques. We evaluate our findings on two databases: the MASS database comprising 19 healthy controls and the DREAMS sleep spindle database comprising eight participants diagnosed with various sleep pathologies. We demonstrate that we can replicate the experts’ sleep spindles assessment accurately in both databases (MASS database: sensitivity: 84%, specificity: 90%, false discovery rate 83%, DREAMS database: sensitivity: 76%, specificity: 92%, false discovery rate: 67%, outperforming six competing automatic sleep spindle detection algorithms in terms of correctly replicating the experts’ assessment of detected spindles.

Synthesis and surface modification of spindle-type magnetic nanoparticles: gold coating and PEG functionalization

OpenAIRE

Mendez-Garza , Juan; Wang , Biran; Madeira , Alexandra; Di-Giorgio , Christophe; Bossis , Georges

2013-01-01

International audience; In this paper, we describe the synthesis of gold coated spindle-type iron nanoparticles and its surface modification by a thiolated fluorescently-labelled polyethylene glycol (PEG) polymer. A forced hydrolysis of ferric salts in the presence of phosphate ions was used to produce α-Fe2O3 spindle-type particles. The oxide powders were first reduced to α-iron under high temperature and controlled dihydrogen atmosphere. Then, the resulting magnetic spindle-type particles w...

White Matter Structure in Older Adults Moderates the Benefit of Sleep Spindles on Motor Memory Consolidation.

Science.gov (United States)

Mander, Bryce A; Zhu, Alyssa H; Lindquist, John R; Villeneuve, Sylvia; Rao, Vikram; Lu, Brandon; Saletin, Jared M; Ancoli-Israel, Sonia; Jagust, William J; Walker, Matthew P

2017-11-29

Sleep spindles promote the consolidation of motor skill memory in young adults. Older adults, however, exhibit impoverished sleep-dependent motor memory consolidation. The underlying pathophysiological mechanism(s) explaining why motor memory consolidation in older adults fails to benefit from sleep remains unclear. Here, we demonstrate that male and female older adults show impoverished overnight motor skill memory consolidation relative to young adults, with the extent of impairment being associated with the degree of reduced frontal fast sleep spindle density. The magnitude of the loss of frontal fast sleep spindles in older adults was predicted by the degree of reduced white matter integrity throughout multiple white matter tracts known to connect subcortical and cortical brain regions. We further demonstrate that the structural integrity of selective white matter fiber tracts, specifically within right posterior corona radiata, right tapetum, and bilateral corpus callosum, statistically moderates whether sleep spindles promoted overnight consolidation of motor skill memory. Therefore, white matter integrity within tracts known to connect cortical sensorimotor control regions dictates the functional influence of sleep spindles on motor skill memory consolidation in the elderly. The deterioration of white matter fiber tracts associated with human brain aging thus appears to be one pathophysiological mechanism influencing subcortical-cortical propagation of sleep spindles and their related memory benefits. SIGNIFICANCE STATEMENT Numerous studies have shown that sleep spindle expression is reduced and sleep-dependent motor memory is impaired in older adults. However, the mechanisms underlying these alterations have remained unknown. The present study reveals that age-related degeneration of white matter within select fiber tracts is associated with reduced sleep spindles in older adults. We further demonstrate that, within these same fiber tracts, the degree of

3ds Max 2012 Bible

CERN Document Server

Murdock, Kelly L

2011-01-01

Updated version of the bestselling 3ds Max book on the market 3ds Max 2012 Bible is one of the most popular 3ds Max how-tos on the market. If you're a beginner just itching to create something right away, the Quick Start project in Part 1 is for you. If you're an experienced user checking out 3ds Max 2012's latest and greatest features, you'll love the fact that the 3ds Max 2012 Bible continues to be the most comprehensive reference on this highly complex application.Find out what's new, what's tried and true, and how creative you can get using the tips, tricks, and techniques in this must-hav

The pacemaker role of thalamic reticular nucleus in controlling spike-wave discharges and spindles.

Science.gov (United States)

Fan, Denggui; Liao, Fucheng; Wang, Qingyun

2017-07-01

Absence epilepsy, characterized by 2-4 Hz spike-wave discharges (SWDs), can be caused by pathological interactions within the thalamocortical system. Cortical spindling oscillations are also demonstrated to involve the oscillatory thalamocortical rhythms generated by the synaptic circuitry of the thalamus and cortex. This implies that SWDs and spindling oscillations can share the common thalamocortical mechanism. Additionally, the thalamic reticular nucleus (RE) is hypothesized to regulate the onsets and propagations of both the epileptic SWDs and sleep spindles. Based on the proposed single-compartment thalamocortical neural field model, we firstly investigate the stimulation effect of RE on the initiations, terminations, and transitions of SWDs. It is shown that the activations and deactivations of RE triggered by single-pulse stimuli can drive the cortical subsystem to behave as the experimentally observed onsets and self-abatements of SWDs, as well as the transitions from 2-spike and wave discharges (2-SWDs) to SWDs. In particular, with increasing inhibition from RE to the specific relay nucleus (TC), rich transition behaviors in cortex can be obtained through the upstream projection path, RE→TC→Cortex. Although some of the complex dynamical patterns can be expected from the earlier single compartment thalamocortical model, the effect of brain network topology on the emergence of SWDs and spindles, as well as the transitions between them, has not been fully investigated. We thereby develop a spatially extended 3-compartment coupled network model with open-/closed-end connective configurations, to investigate the spatiotemporal effect of RE on the SWDs and spindles. Results show that the degrees of activations of RE 1 can induce the rich spatiotemporal evolution properties including the propagations from SWDs to spindles within different compartments and the transitions between them, through the RE 1 →TC 1 →Cortex 1 and Cortex 1 →Cortex 2 →Cortex 3

The pacemaker role of thalamic reticular nucleus in controlling spike-wave discharges and spindles

Science.gov (United States)

Fan, Denggui; Liao, Fucheng; Wang, Qingyun

2017-07-01

Absence epilepsy, characterized by 2-4 Hz spike-wave discharges (SWDs), can be caused by pathological interactions within the thalamocortical system. Cortical spindling oscillations are also demonstrated to involve the oscillatory thalamocortical rhythms generated by the synaptic circuitry of the thalamus and cortex. This implies that SWDs and spindling oscillations can share the common thalamocortical mechanism. Additionally, the thalamic reticular nucleus (RE) is hypothesized to regulate the onsets and propagations of both the epileptic SWDs and sleep spindles. Based on the proposed single-compartment thalamocortical neural field model, we firstly investigate the stimulation effect of RE on the initiations, terminations, and transitions of SWDs. It is shown that the activations and deactivations of RE triggered by single-pulse stimuli can drive the cortical subsystem to behave as the experimentally observed onsets and self-abatements of SWDs, as well as the transitions from 2-spike and wave discharges (2-SWDs) to SWDs. In particular, with increasing inhibition from RE to the specific relay nucleus (TC), rich transition behaviors in cortex can be obtained through the upstream projection path, RE → TC → Cortex . Although some of the complex dynamical patterns can be expected from the earlier single compartment thalamocortical model, the effect of brain network topology on the emergence of SWDs and spindles, as well as the transitions between them, has not been fully investigated. We thereby develop a spatially extended 3-compartment coupled network model with open-/closed-end connective configurations, to investigate the spatiotemporal effect of RE on the SWDs and spindles. Results show that the degrees of activations of RE 1 can induce the rich spatiotemporal evolution properties including the propagations from SWDs to spindles within different compartments and the transitions between them, through the RE 1 → TC 1 → Cortex 1 and Cortex 1 → Cortex 2 �

The effects of eszopiclone on sleep spindles and memory consolidation in schizophrenia: a randomized placebo-controlled trial.

Science.gov (United States)

Wamsley, Erin J; Shinn, Ann K; Tucker, Matthew A; Ono, Kim E; McKinley, Sophia K; Ely, Alice V; Goff, Donald C; Stickgold, Robert; Manoach, Dara S

2013-09-01

In schizophrenia there is a dramatic reduction of sleep spindles that predicts deficient sleep-dependent memory consolidation. Eszopiclone (Lunesta), a non-benzodiazepine hypnotic, acts on γ-aminobutyric acid (GABA) neurons in the thalamic reticular nucleus where spindles are generated. We investigated whether eszopiclone could increase spindles and thereby improve memory consolidation in schizophrenia. In a double-blind design, patients were randomly assigned to receive either placebo or 3 mg of eszopiclone. Patients completed Baseline and Treatment visits, each consisting of two consecutive nights of polysomnography. On the second night of each visit, patients were trained on the motor sequence task (MST) at bedtime and tested the following morning. Academic research center. Twenty-one chronic, medicated schizophrenia outpatients. We compared the effects of two nights of eszopiclone vs. placebo on stage 2 sleep spindles and overnight changes in MST performance. Eszopiclone increased the number and density of spindles over baseline levels significantly more than placebo, but did not significantly enhance overnight MST improvement. In the combined eszopiclone and placebo groups, spindle number and density predicted overnight MST improvement. Eszopiclone significantly increased sleep spindles, which correlated with overnight motor sequence task improvement. These findings provide partial support for the hypothesis that the spindle deficit in schizophrenia impairs sleep-dependent memory consolidation and may be ameliorated by eszopiclone. Larger samples may be needed to detect a significant effect on memory. Given the general role of sleep spindles in cognition, they offer a promising novel potential target for treating cognitive deficits in schizophrenia.

CD30+ lymphoproliferative disorder with spindle-cell morphology.

Science.gov (United States)

Martires, Kathryn J; Cohen, Brandon E; Cassarino, David S

2016-11-01

Lymphomatoid papulosis (LyP) is classified as a CD30+ primary cutaneous lymphoproliferative disease. The phenotypic variability along the spectrum of CD30+ lymphoproliferative diseases is highlighted by the distinct histologic subtypes of LyP types A, B, C, and the more recently described types D, E, and F. We report the case of an elderly woman with a clinical presentation and histopathologic findings consistent with LyP, whose atypical CD30+ infiltrate uniquely demonstrated a spindle-cell morphology. To our knowledge, this is the first reported case of LyP characterized by CD30+ spindle-shaped cells, and may represent a new and distinct histologic variant of LyP. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Multiple Duties for Spindle Assembly Checkpoint Kinases in Meiosis

Science.gov (United States)

Marston, Adele L.; Wassmann, Katja

2017-01-01

Cell division in mitosis and meiosis is governed by evolutionary highly conserved protein kinases and phosphatases, controlling the timely execution of key events such as nuclear envelope breakdown, spindle assembly, chromosome attachment to the spindle and chromosome segregation, and cell cycle exit. In mitosis, the spindle assembly checkpoint (SAC) controls the proper attachment to and alignment of chromosomes on the spindle. The SAC detects errors and induces a cell cycle arrest in metaphase, preventing chromatid separation. Once all chromosomes are properly attached, the SAC-dependent arrest is relieved and chromatids separate evenly into daughter cells. The signaling cascade leading to checkpoint arrest depends on several protein kinases that are conserved from yeast to man. In meiosis, haploid cells containing new genetic combinations are generated from a diploid cell through two specialized cell divisions. Though apparently less robust, SAC control also exists in meiosis. Recently, it has emerged that SAC kinases have additional roles in executing accurate chromosome segregation during the meiotic divisions. Here, we summarize the main differences between mitotic and meiotic cell divisions, and explain why meiotic divisions pose special challenges for correct chromosome segregation. The less-known meiotic roles of the SAC kinases are described, with a focus on two model systems: yeast and mouse oocytes. The meiotic roles of the canonical checkpoint kinases Bub1, Mps1, the pseudokinase BubR1 (Mad3), and Aurora B and C (Ipl1) will be discussed. Insights into the molecular signaling pathways that bring about the special chromosome segregation pattern during meiosis will help us understand why human oocytes are so frequently aneuploid. PMID:29322045

Multiple Duties for Spindle Assembly Checkpoint Kinases in Meiosis

Directory of Open Access Journals (Sweden)

Adele L. Marston

2017-12-01

Full Text Available Cell division in mitosis and meiosis is governed by evolutionary highly conserved protein kinases and phosphatases, controlling the timely execution of key events such as nuclear envelope breakdown, spindle assembly, chromosome attachment to the spindle and chromosome segregation, and cell cycle exit. In mitosis, the spindle assembly checkpoint (SAC controls the proper attachment to and alignment of chromosomes on the spindle. The SAC detects errors and induces a cell cycle arrest in metaphase, preventing chromatid separation. Once all chromosomes are properly attached, the SAC-dependent arrest is relieved and chromatids separate evenly into daughter cells. The signaling cascade leading to checkpoint arrest depends on several protein kinases that are conserved from yeast to man. In meiosis, haploid cells containing new genetic combinations are generated from a diploid cell through two specialized cell divisions. Though apparently less robust, SAC control also exists in meiosis. Recently, it has emerged that SAC kinases have additional roles in executing accurate chromosome segregation during the meiotic divisions. Here, we summarize the main differences between mitotic and meiotic cell divisions, and explain why meiotic divisions pose special challenges for correct chromosome segregation. The less-known meiotic roles of the SAC kinases are described, with a focus on two model systems: yeast and mouse oocytes. The meiotic roles of the canonical checkpoint kinases Bub1, Mps1, the pseudokinase BubR1 (Mad3, and Aurora B and C (Ipl1 will be discussed. Insights into the molecular signaling pathways that bring about the special chromosome segregation pattern during meiosis will help us understand why human oocytes are so frequently aneuploid.

Clathrin heavy chain 1 is required for spindle assembly and chromosome congression in mouse oocytes.

Science.gov (United States)

Zhao, Jie; Wang, Lu; Zhou, Hong-Xia; Liu, Li; Lu, Angeleem; Li, Guang-Peng; Schatten, Heide; Liang, Cheng-Guang

2013-10-01

Clathrin heavy chain 1 (CLTC) has been considered a “moonlighting protein” which acts in membrane trafficking during interphase and in stabilizing spindle fibers during mitosis. However, its roles in meiosis, especially in mammalian oocyte maturation, remain unclear. This study investigated CLTC expression and function in spindle formation and chromosome congression during mouse oocyte meiotic maturation. Our results showed that the expression level of CLTC increased after germinal vesicle breakdown (GVBD) and peaked in the M phase. Immunostaining results showed CLTC distribution throughout the cytoplasm in a cell cycle-dependent manner. Appearance and disappearance of CLTC along with β-tubulin (TUBB) could be observed during spindle dynamic changes. To explore the relationship between CLTC and microtubule dynamics, oocytes at metaphase were treated with taxol or nocodazole. CLTC colocalized with TUBB at the enlarged spindle and with cytoplasmic asters after taxol treatment; it disassembled and distributed into the cytoplasm along with TUBB after nocodazole treatment. Disruption of CLTC function using stealth siRNA caused a decreased first polar body extrusion rate and extensive spindle formation and chromosome congression defects. Taken together, these results show that CLTC plays an important role in spindle assembly and chromosome congression through a microtubule correlation mechanism during mouse oocyte maturation.

Spindle Cell Metaplastic Breast Cancer: Case Report

Directory of Open Access Journals (Sweden)

Dursun Ozgur Karakas

2013-08-01

Conclusion: Spindle cell metaplastic breast cancer must be considered in differential diagnosis of breast cancers, and preoperative immunohistochemical examination, including cytokeratin and vimentin, must be added to pathological examination in intervening cases. [Arch Clin Exp Surg 2013; 2(4.000: 259-262

Direct kinetochore?spindle pole connections are not required for chromosome segregation

OpenAIRE

Sikirzhytski, Vitali; Magidson, Valentin; Steinman, Jonathan B.; He, Jie; Le Berre, Ma?l; Tikhonenko, Irina; Ault, Jeffrey G.; McEwen, Bruce F.; Chen, James K.; Sui, Haixin; Piel, Matthieu; Kapoor, Tarun M.; Khodjakov, Alexey

2014-01-01

Segregation of genetic material occurs when chromosomes move to opposite spindle poles during mitosis. This movement depends on K-fibers, specialized microtubule (MT) bundles attached to the chromosomes? kinetochores. A long-standing assumption is that continuous K-fibers connect every kinetochore to a spindle pole and the force for chromosome movement is produced at the kinetochore and coupled with MT depolymerization. However, we found that chromosomes still maintained their position at the...

Smurf2 as a novel mitotic regulator: From the spindle assembly checkpoint to tumorigenesis

Directory of Open Access Journals (Sweden)

Moore Finola E

2009-07-01

Full Text Available Abstract The execution of the mitotic program with high fidelity is dependent upon precise spatiotemporal regulation of posttranslational protein modifications. For example, the timely polyubiquitination of critical mitotic regulators by Anaphase Promoting Complex/Cyclosome (APC/C is essential for the metaphase to anaphase transition and mitotic exit. The spindle assembly checkpoint prevents unscheduled activity of APC/C-Cdc20 in early mitosis, allowing bipolar attachment of kinetochores to mitotic spindle and facilitating equal segregation of sister chromatids. The critical effector of the spindle checkpoint, Mitotic arrest deficient 2 (Mad2, is recruited to unattached kinetochores forming a complex with other regulatory proteins to efficiently and cooperatively inhibit APC/C-Cdc20. A weakened and/or dysfunctional spindle checkpoint has been linked to the development of genomic instability in both cell culture and animal models, and evidence suggests that aberrant regulation of the spindle checkpoint plays a critical role in human carcinogenesis. Recent studies have illuminated a network of both degradative and non-degradative ubiquitination events that regulate the metaphase to anaphase transition and mitotic exit. Within this context, our recent work showed that the HECT (Homologous to E6-AP C-terminus-family E3 ligase Smurf2 (Smad specific ubiquitin regulatory factor 2, known as a negative regulator of transforming growth factor-beta (TGF-β signaling, is required for a functional spindle checkpoint by promoting the functional localization and stability of Mad2. Here we discuss putative models explaining the role of Smurf2 as a new regulator in the spindle checkpoint. The dynamic mitotic localization of Smurf2 to the centrosome and other critical mitotic structures provides implications about mitotic checkpoint control dependent on various ubiquitination events. Finally, deregulated Smurf2 activity may contribute to carcinogenesis by

Thermal Error Modelling of the Spindle Using Data Transformation and Adaptive Neurofuzzy Inference System

Directory of Open Access Journals (Sweden)

Yanlei Li

2015-01-01

Full Text Available This paper proposes a new method for predicting spindle deformation based on temperature data. The method introduces the adaptive neurofuzzy inference system (ANFIS, which is a neurofuzzy modeling approach that integrates the kernel and geometrical transformations. By utilizing data transformation, the number of ANFIS rules can be effectively reduced and the predictive model structure can be simplified. To build the predictive model, we first map the original temperature data to a feature space with Gaussian kernels. We then process the mapped data with the geometrical transformation and make the data gather in the square region. Finally, the transformed data are used as input to train the ANFIS. A verification experiment is conducted to evaluate the performance of the proposed method. Six Pt100 thermal resistances are used to monitor the spindle temperature, and a laser displacement sensor is used to detect the spindle deformation. Experimental results show that the proposed method can precisely predict the spindle deformation and greatly improve the thermal performance of the spindle. Compared with back propagation (BP networks, the proposed method is more suitable for complex working conditions in practical applications.

A min-max variational principle

International Nuclear Information System (INIS)

Georgiev, P.G.

1995-11-01

In this paper a variational principle for min-max problems is proved that is of the same spirit as Deville-Godefroy-Zizler's variational principle for minimization problems. A localization theorem in which the mini-max points for the perturbed function with respect top a given ε-min-max point are localized is presented. 3 refs

Turbulence influence on optimum tip speed ratio for a 200 kW vertical axis wind turbine

Science.gov (United States)

Möllerström, E.; Eriksson, S.; Goude, A.; Ottermo, F.; Hylander, J.

2016-09-01

The influence of turbulence intensity (TI) on the tip speed ratio for maximum power coefficient, here called λCp_max, is studied for a 200 kW VAWT H-rotor using logged data from a 14 month period with the H-rotor operating in wind speeds up to 9 m/s. The TI - λCp_max relation is examined by dividing 10 min mean values in different turbulence intensity ranges and producing multiple CP(λ) curves. A clear positive relation between TI and λCp_max is shown and is further strengthened as possible secondary effects are examined and deemed non-essential. The established relation makes it possible to tune the control strategy to enhance the total efficiency of the turbine.

Analisis Kinerja Subscriber Station WiMAX di Urban Area Bandung

Directory of Open Access Journals (Sweden)

DWI ARYANTA

2017-06-01

Full Text Available ABSTRAK   Teknologi komunikasi wireless semakin pesat mengalami perkembangan. WiMAX  merupakan suatu teknologi broadband yang didukung oleh standar IEEE 802.16d (802.16-2004 yang mampu memberikan layanan data berkecepatan tinggi hingga 75 Mbps dalam radius maksimal 40-50 km pada bandwidth 20 MHz. Alokasi frekuensi yang dipakai Indonesia untuk jaringan WiMAX  ini ialah 3,3 – 3,4 GHz. Penelitian ini dilakukan dengan melakukan proses pengukuran kinerja perangkat radio WiMAX  yaitu HiMax 331-SS. Proses pengukuran dilakukan antara CPE dan base station dengan antenna sektoral 1200 pada ketinggian 45 m. Lokasi pengukuran dilakukan di beberapa area kota Bandung yang telah ditentukan sebelumnya. Hasil pengukuran memperlihatkan nilai CINR tertinggi adalah 31 dB dengan modulasi 64 QAM – ¾ dan terendah nilai 10 dB dengan modulasi BPSK 1/2. Nilai RSSI tertinggi -54 dBm berada dan nilai RSSI terendah -89 dBm. Nilai throughput tertinggi untuk layanan streaming video sebesar  1000,8 kbps (downlink dengan modulasi 64 QAM – ¾. Nilai delay terendah sebesar 56,247 ms pada kondisi LOS dan tertinggi sebesar 139,5 ms pada kondisi NLOS. Nilai terbesar packet loss sebesar 20% yaitu pada lokasi pengukuran terjauh 14,3 km. Kata Kunci : delay, packet loss, RSSI, CINR, throughput, CPE, WiMAX .   ABSTRACT   Wireless communication technologies have evolved more rapidly. WiMAX  is a broadband technology that is supported by the IEEE standard 802.16-2004/d which is able to provide high speed data services of up to 75 Mbps within a radius of 40-50 km at a maximum bandwidth of 20 MHz. Indonesia frequency allocation used for the WiMAX  network is 3.3 to 3.4 GHz. This study was conducted with the performance measurement process that is Himax 331 WiMAX  radio - SS. Process measurement is made between the CPE and base station sector antennas at a height of 45 m in 1200. Locations measurements performed in several areas of Bandung predetermined. The measurement

Cytokeratin: a Shortcut to Diagnose Spindle Cell Carcinoma

Directory of Open Access Journals (Sweden)

Dehghani Nazhvani A

2017-09-01

Full Text Available A relatively rare subtype of squamous cell carcinoma (SCC is spindle cell carcinoma (SPCC. It is composed of epithelium-derived spindle cells arranged in sheets with mesenchymal properties and small, hard-ly detectable regions of SCC, challenging its definite diagnosis. We encountered five cases of SPCC. In case one, chronic inflammation and subepithelial blister with leukoplakia was found 5 years before our examination. And later, exophytic features, keratotic papules and scar with elevated margins was seen on lateral border of the tongue. In case two, three and four, an abnormal soft tissue elevations were examined, and in the fifth case we examined the soft and bony speci-men from the posterior aspect of maxillary ridge. We evaluated all of them histologically and immunohistochemically for cytokeratin to reach final diagnosis.

Declarative memory performance is associated with the number of sleep spindles in elderly women.

Science.gov (United States)

Seeck-Hirschner, Mareen; Baier, Paul Christian; Weinhold, Sara Lena; Dittmar, Manuela; Heiermann, Steffanie; Aldenhoff, Josef B; Göder, Robert

2012-09-01

Recent evidence suggests that the sleep-dependent consolidation of declarative memory relies on the nonrapid eye movement rather than the rapid eye movement phase of sleep. In addition, it is known that aging is accompanied by changes in sleep and memory processes. Hence, the purpose of this study was to investigate the overnight consolidation of declarative memory in healthy elderly women. Sleep laboratory of University. Nineteen healthy elderly women (age range: 61-74 years). We used laboratory-based measures of sleep. To test declarative memory, the Rey-Osterrieth Complex Figure Test was performed. Declarative memory performance in elderly women was associated with Stage 2 sleep spindle density. Women characterized by high memory performance exhibited significantly higher numbers of sleep spindles and higher spindle density compared with women with generally low memory performance. The data strongly support theories suggesting a link between sleep spindle activity and declarative memory consolidation.

Semaphorin-Plexin Signaling Controls Mitotic Spindle Orientation during Epithelial Morphogenesis and Repair

DEFF Research Database (Denmark)

Xia, Jingjing; Swiercz, Jakub M.; Bañón-Rodríguez, Inmaculada

2015-01-01

Morphogenesis, homeostasis, and regeneration of epithelial tissues rely on the accurate orientation of cell divisions, which is specified by the mitotic spindle axis. To remain in the epithelial plane, symmetrically dividing epithelial cells align their mitotic spindle axis with the plane. Here, we...... show that this alignment depends on epithelial cell-cell communication via semaphorin-plexin signaling. During kidney morphogenesis and repair, renal tubular epithelial cells lacking the transmembrane receptor Plexin-B2 or its semaphorin ligands fail to correctly orient the mitotic spindle, leading...... to severe defects in epithelial architecture and function. Analyses of a series of transgenic and knockout mice indicate that Plexin-B2 controls the cell division axis by signaling through its GTPase-activating protein (GAP) domain and Cdc42. Our data uncover semaphorin-plexin signaling as a central...

Constitutive Cdk2 activity promotes aneuploidy while altering the spindle assembly and tetraploidy checkpoints

DEFF Research Database (Denmark)

Jahn, Stephan C; Corsino, Patrick E; Davis, Bradley J

2013-01-01

instability. Expression of these complexes in the MCF10A cell line leads to retinoblastoma protein (Rb) hyperphosphorylation, a subsequent increase in proliferation rate, and increased expression of the spindle assembly checkpoint protein Mad2. This results in a strengthening of the spindle assembly...

Radiation-induced spindle cell sarcoma: A rare case report

Directory of Open Access Journals (Sweden)

Khan Mubeen

2009-01-01

Full Text Available Ionizing radiation has been known to induce malignant transformation in human beings. Radiation-induced sarcomas are a late sequel of radiation therapy. Most sarcomas have been reported to occur after exposure to a radiation dose of 55 Gray (Gy and above, with a dose ranging from 16 to 112 Gys. Spindle cell sarcomas, arising after radiotherapy given to treat the carcinoma of head and neck region is a very uncommon sequel. This is a rare case report of spindle cell sarcoma of left maxilla, in a 24-year-old male, occurring as a late complication of radiotherapy with Cobalt-60 given for the treatment of retinoblastoma of the left eye 21 years back.

The role of sleep spindles and slow-wave activity in integrating new information in semantic memory.

Science.gov (United States)

Tamminen, Jakke; Lambon Ralph, Matthew A; Lewis, Penelope A

2013-09-25

Assimilating new information into existing knowledge is a fundamental part of consolidating new memories and allowing them to guide behavior optimally and is vital for conceptual knowledge (semantic memory), which is accrued over many years. Sleep is important for memory consolidation, but its impact upon assimilation of new information into existing semantic knowledge has received minimal examination. Here, we examined the integration process by training human participants on novel words with meanings that fell into densely or sparsely populated areas of semantic memory in two separate sessions. Overnight sleep was polysomnographically monitored after each training session and recall was tested immediately after training, after a night of sleep, and 1 week later. Results showed that participants learned equal numbers of both word types, thus equating amount and difficulty of learning across the conditions. Measures of word recognition speed showed a disadvantage for novel words in dense semantic neighborhoods, presumably due to interference from many semantically related concepts, suggesting that the novel words had been successfully integrated into semantic memory. Most critically, semantic neighborhood density influenced sleep architecture, with participants exhibiting more sleep spindles and slow-wave activity after learning the sparse compared with the dense neighborhood words. These findings provide the first evidence that spindles and slow-wave activity mediate integration of new information into existing semantic networks.

Method for automated building of spindle thermal model with use of CAE system

Science.gov (United States)

Kamenev, S. V.

2018-03-01

The spindle is one of the most important units of the metal-cutting machine tool. Its performance is critical to minimize the machining error, especially the thermal error. Various methods are applied to improve the thermal behaviour of spindle units. One of the most important methods is mathematical modelling based on the finite element analysis. The most common approach for its realization is the use of CAE systems. This approach, however, is not capable to address the number of important effects that need to be taken into consideration for proper simulation. In the present article, the authors propose the solution to overcome these disadvantages using automated thermal model building for the spindle unit utilizing the CAE system ANSYS.

Increases in .VO2max with "live high-train low" altitude training: role of ventilatory acclimatization.

Science.gov (United States)

Wilhite, Daniel P; Mickleborough, Timothy D; Laymon, Abigail S; Chapman, Robert F

2013-02-01

The purpose of this study was to estimate the percentage of the increase in whole body maximal oxygen consumption (.VO(2max)) that is accounted for by increased respiratory muscle oxygen uptake after altitude training. Six elite male distance runners (.VO(2max) = 70.6 ± 4.5 ml kg(-1) min(-1)) and one elite female distance runner (.VO(2max)) = 64.7 ml kg(-1) min(-1)) completed a 28-day "live high-train low" training intervention (living elevation, 2,150 m). Before and after altitude training, subjects ran at three submaximal speeds, and during a separate session, performed a graded exercise test to exhaustion. A regression equation derived from published data was used to estimate respiratory muscle .VO(2) (.VO(2RM)) using our ventilation (.VE) values. .VO(2RM) was also estimated retrospectively from a larger group of distance runners (n = 22). .VO(2max) significantly (p altitude (196 ± 59 ml min(-1)), while (.VE) at .VO(2max) also significantly (p altitude (201 ± 36 ml min(-1)), along with a 10.8 ± 2.1 l min(-1) increase in (.VE), thus requiring an estimated 27 % of Δ .VO(2max) Our data suggest that a substantial portion of the improvement in .VO(2max) with chronic altitude training goes to fuel the respiratory muscles as opposed to the musculature which directly contributes to locomotion. Consequently, the time-course of decay in ventilatory acclimatization following return to sea-level may have an impact on competitive performance.

JMJD5 (Jumonji Domain-containing 5) Associates with Spindle Microtubules and Is Required for Proper Mitosis.

Science.gov (United States)

He, Zhimin; Wu, Junyu; Su, Xiaonan; Zhang, Ye; Pan, Lixia; Wei, Huimin; Fang, Qiang; Li, Haitao; Wang, Da-Liang; Sun, Fang-Lin

2016-02-26

Precise mitotic spindle assembly is a guarantee of proper chromosome segregation during mitosis. Chromosome instability caused by disturbed mitosis is one of the major features of various types of cancer. JMJD5 has been reported to be involved in epigenetic regulation of gene expression in the nucleus, but little is known about its function in mitotic process. Here we report the unexpected localization and function of JMJD5 in mitotic progression. JMJD5 partially accumulates on mitotic spindles during mitosis, and depletion of JMJD5 results in significant mitotic arrest, spindle assembly defects, and sustained activation of the spindle assembly checkpoint (SAC). Inactivating SAC can efficiently reverse the mitotic arrest caused by JMJD5 depletion. Moreover, JMJD5 is found to interact with tubulin proteins and associate with microtubules during mitosis. JMJD5-depleted cells show a significant reduction of α-tubulin acetylation level on mitotic spindles and fail to generate enough interkinetochore tension to satisfy the SAC. Further, JMJD5 depletion also increases the susceptibility of HeLa cells to the antimicrotubule agent. Taken together, these results suggest that JMJD5 plays an important role in regulating mitotic progression, probably by modulating the stability of spindle microtubules. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Combining time-frequency and spatial information for the detection of sleep spindles

Directory of Open Access Journals (Sweden)

Christian eO'Reilly

2015-02-01

Full Text Available EEG sleep spindles are short (0.5-2.0 s bursts of activity in the 11-16 Hz band occurring during non-rapid eye movement (NREM sleep. This sporadic activity is thought to play a role in memory consolidation, brain plasticity, and protection of sleep integrity. Many automatic detectors have been proposed to assist or replace experts for sleep spindle scoring. However, these algorithms usually detect too many events making it difficult to achieve a good tradeoff between sensitivity (Se and false detection rate (FDr. In this work, we propose a semi-automatic detector comprising a sensitivity phase based on well-established criteria followed by a specificity phase using spatial and spectral criteria.In the sensitivity phase, selected events are those which amplitude in the 10 – 16 Hz band and spectral ratio characteristics both reject a null hypothesis (p <0.1 stating that the considered event is not a spindle. This null hypothesis is constructed from events occurring during rapid eye movement (REM sleep epochs. In the specificity phase, a hierarchical clustering of the selected candidates is done based on events’ frequency and spatial position along the anterior-posterior axis. Only events from the classes grouping most (at least 80% spindles scored by an expert are kept. We obtain Se = 93.2% and FDr = 93.0% in the first phase and Se = 85.4% and FDr = 86.2% in the second phase. For these two phases, Matthew’s correlation coefficients are respectively 0.228 and 0.324. Results suggest that spindles are defined by specific spatio-spectral properties and that automatic detection methods can be improved by considering these features.

Sleep Spindle Density Predicts the Effect of Prior Knowledge on Memory Consolidation

Science.gov (United States)

Lambon Ralph, Matthew A.; Kempkes, Marleen; Cousins, James N.; Lewis, Penelope A.

2016-01-01

Information that relates to a prior knowledge schema is remembered better and consolidates more rapidly than information that does not. Another factor that influences memory consolidation is sleep and growing evidence suggests that sleep-related processing is important for integration with existing knowledge. Here, we perform an examination of how sleep-related mechanisms interact with schema-dependent memory advantage. Participants first established a schema over 2 weeks. Next, they encoded new facts, which were either related to the schema or completely unrelated. After a 24 h retention interval, including a night of sleep, which we monitored with polysomnography, participants encoded a second set of facts. Finally, memory for all facts was tested in a functional magnetic resonance imaging scanner. Behaviorally, sleep spindle density predicted an increase of the schema benefit to memory across the retention interval. Higher spindle densities were associated with reduced decay of schema-related memories. Functionally, spindle density predicted increased disengagement of the hippocampus across 24 h for schema-related memories only. Together, these results suggest that sleep spindle activity is associated with the effect of prior knowledge on memory consolidation. SIGNIFICANCE STATEMENT Episodic memories are gradually assimilated into long-term memory and this process is strongly influenced by sleep. The consolidation of new information is also influenced by its relationship to existing knowledge structures, or schemas, but the role of sleep in such schema-related consolidation is unknown. We show that sleep spindle density predicts the extent to which schemas influence the consolidation of related facts. This is the first evidence that sleep is associated with the interaction between prior knowledge and long-term memory formation. PMID:27030764

Experimental Analysis and Full Prediction Model of a 5-DOF Motorized Spindle

Directory of Open Access Journals (Sweden)

Weiyu Zhang

2017-01-01

Full Text Available The cost and power consumption of DC power amplifiers are much greater than that of AC power converters. Compared to a motorized spindle supported with DC magnetic bearings, a motorized spindle supported with AC magnetic bearings is inexpensive and more efficient. This paper studies a five-degrees-of-freedom (5-DOF motorized spindle supported with AC hybrid magnetic bearings (HMBs. Most models of suspension forces, except a “switching model”, are quite accurate, but only in a particular operating area and not in regional coverage. If a “switching model” is applied to a 5-DOF motorized spindle, the real-time performance of the control system can be significantly decreased due to the large amount of data processing for both displacement and current. In order to solve this defect, experiments based on the “switching model” are performed, and the resulting data are analyzed. Using the data analysis results, a “full prediction model” based on the operating state is proposed to improve real-time performance and precision. Finally, comparative, verification and stiffness tests are conducted to verify the improvement of the proposed model. Results of the tests indicate that the rotor has excellent characteristics, such as good real-time performance, superior anti-interference performance with load and the accuracy of the model in full zone. The satisfactory experimental results demonstrate the effectiveness of the “full prediction model” applied to the control system under different operating stages. Therefore, the results of the experimental analysis and the proposed full prediction model can provide a control system of a 5-DOF motorized spindle with the most suitable mathematical models of the suspension force.

Error Correction of Radial Displacement in Grinding Machine Tool Spindle by Optimizing Shape and Bearing Tuning

OpenAIRE

Khairul Jauhari; Achmad Widodo; Ismoyo Haryanto

2015-01-01

In this article, the radial displacement error correction capability of a high precision spindle grinding caused by unbalance force was investigated. The spindle shaft is considered as a flexible rotor mounted on two sets of angular contact ball bearing. Finite element methods (FEM) have been adopted for obtaining the equation of motion of the spindle. In this paper, firstly, natural frequencies, critical frequencies, and amplitude of the unbalance response caused by resi...

The function of the sleep spindle: a physiological index of intelligence and a mechanism for sleep-dependent memory consolidation.

Science.gov (United States)

Fogel, Stuart M; Smith, Carlyle T

2011-04-01

Until recently, the electrophysiological mechanisms involved in strengthening new memories into a more permanent form during sleep have been largely unknown. The sleep spindle is an event in the electroencephalogram (EEG) characterizing Stage 2 sleep. Sleep spindles may reflect, at the electrophysiological level, an ideal mechanism for inducing long-term synaptic changes in the neocortex. Recent evidence suggests the spindle is highly correlated with tests of intellectual ability (e.g.; IQ tests) and may serve as a physiological index of intelligence. Further, spindles increase in number and duration in sleep following new learning and are correlated with performance improvements. Spindle density and sigma (14-16Hz) spectral power have been found to be positively correlated with performance following a daytime nap, and animal studies suggest the spindle is involved in a hippocampal-neocortical dialogue necessary for memory consolidation. The findings reviewed here collectively provide a compelling body of evidence that the function of the sleep spindle is related to intellectual ability and memory consolidation. Copyright © 2010 Elsevier Ltd. All rights reserved.

TFG-MET fusion in an infantile spindle cell sarcoma with neural features.

Science.gov (United States)

Flucke, Uta; van Noesel, Max M; Wijnen, Marc; Zhang, Lei; Chen, Chun-Liang; Sung, Yun-Shao; Antonescu, Cristina R

2017-09-01

An increasing number of congenital and infantile sarcomas displaying a primitive, monomorphic spindle cell phenotype have been characterized to harbor recurrent gene fusions, including infantile fibrosarcoma and congenital spindle cell rhabdomyosarcoma. Here, we report an unusual spindle cell sarcoma presenting as a large and infiltrative pelvic soft tissue mass in a 4-month-old girl, which revealed a novel TFG-MET gene fusion by whole transcriptome RNA sequencing. The tumor resembled the morphology of an infantile fibrosarcoma with both fascicular and patternless growth, however, it expressed strong S100 protein immunoreactivity, while lacking SOX10 staining and retaining H3K27me3 expression. Although this immunoprofile suggested partial neural/neuroectodermal differentiation, overall features were unusual and did not fit into any known tumor types (cellular schwannoma, MPNST), raising the possibility of a novel pathologic entity. The TFG-MET gene fusion expands the genetic spectrum implicated in the pathogenesis of congenital spindle cell sarcomas, with yet another example of kinase oncogenic activation through chromosomal translocation. The discovery of this new fusion is significant since the resulting MET activation can potentially be inhibited by targeted therapy, as MET inhibitors are presently available in clinical trials. © 2017 Wiley Periodicals, Inc.

Time-frequency dynamics during sleep spindles on the EEG in rodents with a genetic predisposition to absence epilepsy (WAG/Rij rats)

Science.gov (United States)

Hramov, Alexander E.; Sitnikova, Evgenija Y.; Pavlov, Alexey N.; Grubov, Vadim V.; Koronovskii, Alexey A.; Khramova, Marina V.

2015-03-01

Sleep spindles are known to appear spontaneously in the thalamocortical neuronal network of the brain during slow-wave sleep; pathological processes in the thalamocortical network may be the reason of the absence epilepsy. The aim of the present work is to study developed changes in the time-frequency structure of sleep spindles during the progressive development of the absence epilepsy in WAG/Rij rats. EEG recordings were made at age 7 and 9 months. Automatic recognition and subsequent analysis of sleep spindles on the EEG were performed using the continuous wavelet transform. The duration of epileptic discharges and the total duration of epileptic activity were found to increase with age, while the duration of sleep spindles, conversely, decreased. In terms of the mean frequency, sleep spindles could be divided into three classes: `slow' (mean frequency 9.3Hz), `medium' (11.4Hz), and `fast' (13.5Hz). Slow and medium (transitional) spindles in five-month-old animals showed increased frequency from the beginning to the end of the spindle. The more intense the epilepsy is, the shorter are the durations of spindles of all types. The mean frequencies of `medium' and `fast' spindles were higher in rats with more intense signs of epilepsy. Overall, high epileptic activity in WAG/Rij rats was linked with significant changes in spindles of the transitional type, with less marked changes in the two traditionally identified types of spindle, slow and fast.

Sleep spindles are related to schizotypal personality traits and thalamic glutamine/glutamate in healthy subjects.

Science.gov (United States)

Lustenberger, Caroline; O'Gorman, Ruth L; Pugin, Fiona; Tüshaus, Laura; Wehrle, Flavia; Achermann, Peter; Huber, Reto

2015-03-01

Schizophrenia is a severe mental disorder affecting approximately 1% of the worldwide population. Yet, schizophrenia-like experiences (schizotypy) are very common in the healthy population, indicating a continuum between normal mental functioning and the psychosis found in schizophrenic patients. A continuum between schizotypy and schizophrenia would be supported if they share the same neurobiological origin. Two such neurobiological markers of schizophrenia are: (1) a reduction of sleep spindles (12-15 Hz oscillations during nonrapid eye movement sleep), likely reflecting deficits in thalamo-cortical circuits and (2) increased glutamine and glutamate (Glx) levels in the thalamus. Thus, this study aimed to investigate whether sleep spindles and Glx levels are related to schizotypal personality traits in healthy subjects. Twenty young male subjects underwent 2 all-night sleep electroencephalography recordings (128 electrodes). Sleep spindles were detected automatically. After those 2 nights, thalamic Glx levels were measured by magnetic resonance spectroscopy. Subjects completed a magical ideation scale to assess schizotypy. Sleep spindle density was negatively correlated with magical ideation (r = -.64, P .1). The common relationship of sleep spindle density with schizotypy and thalamic Glx levels indicates a neurobiological overlap between nonclinical schizotypy and schizophrenia. Thus, sleep spindle density and magical ideation may reflect the anatomy and efficiency of the thalamo-cortical system that shows pronounced impairment in patients with schizophrenia. © The Author 2014. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Analysis of radial runout for symmetric and asymmetric HDD spindle motors with rotor eccentricity

International Nuclear Information System (INIS)

Kim, T.-J.; Kim, K.-T.; Hwang, S.-M.; Lee, S.-B.; Park, N.-G.

2001-01-01

Radial runout of disk drive spindle is one of the major limiting factors in achieving higher track densities in hard disk drives. Mechanical, magnetic and their coupled origins, such as unbalanced mass, reaction forces and magnetic forces, introduce radial runout of spindle motors. In this paper, radial magnetic forces are calculated with respect to the various rotor eccentricities using analytic method. Based on the results of the radial magnetic forces, the radial runout of the spindle motor is analyzed using finite element and transfer matrices. Results show that an asymmetric motor has a worse performance on unbalanced magnetic forces and radial runout when mechanical and magnetic coupling exists

Muscle spindle autogenetic inhibition in the extraocular muscles of lamb.

Science.gov (United States)

Pettorossi, V E; Filippi, G M

1981-09-01

The role of extraocular muscle (EOM) proprioceptors on eye motility has been investigated in lambs on "encéphale isolé", by evaluating the tension of EOMs at various lengths and velocities of stretch before and after proprioceptive blocks. The EOM tension, in the absence of proprioceptive input, was higher than in normal conditions. Such an effect occurred at lengthening values greater than 3 mm of stretch from resting muscle length, corresponding to 18 degrees of eye deviation and was dependent on the velocity of the stretch, being more effective at high velocity. The muscle receptors responsible for this effect was determined by comparing the sensitivity to vibratory stimulation of spindles and tendon organs to the amount of inhibition provoked by the same stimulation on an EOM electromyographic activity. The tension inhibition appeared to be correlated to muscle spindle activation. Thus, the presence of muscle spindles can determine a reduction of the tension within the stretched muscles. This result suggests that the EOM length and velocity signals operate moment to moment reduction on the stiffness of the muscle which antagonizes eye displacement, thus facilitating the ocular movements.

Regulation of spindle orientation and neural stem cell fate in the Drosophila optic lobe

Directory of Open Access Journals (Sweden)

Brand Andrea H

2007-01-01

Full Text Available Abstract Background The choice of a stem cell to divide symmetrically or asymmetrically has profound consequences for development and disease. Unregulated symmetric division promotes tumor formation, whereas inappropriate asymmetric division affects organ morphogenesis. Despite its importance, little is known about how spindle positioning is regulated. In some tissues cell fate appears to dictate the type of cell division, whereas in other tissues it is thought that stochastic variation in spindle position dictates subsequent sibling cell fate. Results Here we investigate the relationship between neural progenitor identity and spindle positioning in the Drosophila optic lobe. We use molecular markers and live imaging to show that there are two populations of progenitors in the optic lobe: symmetrically dividing neuroepithelial cells and asymmetrically dividing neuroblasts. We use genetically marked single cell clones to show that neuroepithelial cells give rise to neuroblasts. To determine if a change in spindle orientation can trigger a neuroepithelial to neuroblast transition, we force neuroepithelial cells to divide along their apical/basal axis by misexpressing Inscuteable. We find that this does not induce neuroblasts, nor does it promote premature neuronal differentiation. Conclusion We show that symmetrically dividing neuroepithelial cells give rise to asymmetrically dividing neuroblasts in the optic lobe, and that regulation of spindle orientation and division symmetry is a consequence of cell type specification, rather than a mechanism for generating cell type diversity.

Sleep spindle activity in double cortex syndrome: a case report.

Science.gov (United States)

Sforza, Emilia; Marcoz, Jean-Pierre; Foletti, Giovanni

2010-09-01

Cortical dysgenesis is increasingly recognised as a cause of epilepsy. We report a case with double cortex heterotopia and secondarily generalized seizures with a generalised spike wave pattern. During the course of the disease, the child developed electrical status epilepticus in slow wave sleep. From the first examination, sleep pattern revealed increased frequency and amplitude of spindle activity, more evident in anterior areas. The role of the thalamocortical pathway in increased sleep spindle activity is discussed with emphasis on the possible role of altered thalamocortical pathways in abnormal cortical migration. A strong suspicion of cortical dysgenesis may therefore be based on specific EEG sleep patterns.

Dishevelled binds the Discs large 'Hook' domain to activate GukHolder-dependent spindle positioning in Drosophila.

Directory of Open Access Journals (Sweden)

Joshua D Garcia

Full Text Available Communication between cortical cell polarity cues and the mitotic spindle ensures proper orientation of cell divisions within complex tissues. Defects in mitotic spindle positioning have been linked to various developmental disorders and have recently emerged as a potential contributor to tumorigenesis. Despite the importance of this process to human health, the molecular mechanisms that regulate spindle orientation are not fully understood. Moreover, it remains unclear how diverse cortical polarity complexes might cooperate to influence spindle positioning. We and others have demonstrated spindle orientation roles for Dishevelled (Dsh, a key regulator of planar cell polarity, and Discs large (Dlg, a conserved apico-basal cell polarity regulator, effects which were previously thought to operate within distinct molecular pathways. Here we identify a novel direct interaction between the Dsh-PDZ domain and the alternatively spliced "I3-insert" of the Dlg-Hook domain, thus establishing a potential convergent Dsh/Dlg pathway. Furthermore, we identify a Dlg sequence motif necessary for the Dsh interaction that shares homology to the site of Dsh binding in the Frizzled receptor. Expression of Dsh enhanced Dlg-mediated spindle positioning similar to deletion of the Hook domain. This Dsh-mediated activation was dependent on the Dlg-binding partner, GukHolder (GukH. These results suggest that Dsh binding may regulate core interdomain conformational dynamics previously described for Dlg. Together, our results identify Dlg as an effector of Dsh signaling and demonstrate a Dsh-mediated mechanism for the activation of Dlg/GukH-dependent spindle positioning. Cooperation between these two evolutionarily-conserved cell polarity pathways could have important implications to both the development and maintenance of tissue homeostasis in animals.

The role of p53 in the response to mitotic spindle damage

International Nuclear Information System (INIS)

Meek, D.W.

2000-01-01

The p53 tumour suppressor protein has defined roles in G1/S and G2/M cell cycle checkpoint in response to a range of cellular stresses including DNA damage, dominant oncogene expression, hypoxia, metabolic changes and viral infection. In addition to these responses, p53 can also be activated when damage occurs to the mitotic spindle. Initially, spindle damage activates a p53-independent checkpoint which functions at the metaphase-anaphase transition and prevents cells from progressing through mitosis until the completion of spindle formation. Cells eventually escape from this block (a process termed 'mitotic slippage'), and an aberrant mitosis ensues in which sister chromatids fail to segregate properly. After a delay period, p53 responds to this mitotic failure by instituting a G1-like growth arrest, with an intact nucleus containing 4N DNA, but without the cells undergoing division. Cells lacking wild-type p53 are still able to arrest transiently at mitosis, and also fail to undergo division, underscoring that the delay in mitosis is p53-independent. However, these cells are not prevented from re-entering the cell cycle and can reduplicate their DNA unchecked, leading to polyploidy. Additionally, p53-null cells which experience spindle failure often show the appearance of micronuclei arising from poorly segregated chromosomes which have de-condensed and been enclosed in a nuclear envelope. The ability of p53 to prevent their formation suggests an additional G2 involvement which prevents nuclear breakdown prior to mitosis. The molecular mechanism by which p53 is able to sense mitotic failure is still unknown, but may be linked to the ability of p53 to regulate duplication of the centrosome, the organelle which nucleates spindle formation. (authors)

Spindles and active vortices in a model of confined filament-motor mixtures.

Science.gov (United States)

Head, David A; Briels, Wj; Gompper, Gerhard

2011-11-16

Robust self-organization of subcellular structures is a key principle governing the dynamics and evolution of cellular life. In fission yeast cells undergoing division, the mitotic spindle spontaneously emerges from the interaction of microtubules, motor proteins and the confining cell walls, and asters and vortices have been observed to self-assemble in quasi-two dimensional microtubule-kinesin assays. There is no clear microscopic picture of the role of the active motors driving this pattern formation, and the relevance of continuum modeling to filament-scale structures remains uncertain. Here we present results of numerical simulations of a discrete filament-motor protein model confined to a pressurised cylindrical box. Stable spindles, nematic configurations, asters and high-density semi-asters spontaneously emerge, the latter pair having also been observed in cytosol confined within emulsion droplets. State diagrams are presented delineating each stationary state as the pressure, motor speed and motor density are varied. We further highlight a parameter regime where vortices form exhibiting collective rotation of all filaments, but have a finite life-time before contracting to a semi-aster. Quantifying the distribution of life-times suggests this contraction is a Poisson process. Equivalent systems with fixed volume exhibit persistent vortices with stochastic switching in the direction of rotation, with switching times obeying similar statistics to contraction times in pressurised systems. Furthermore, we show that increasing the detachment rate of motors from filament plus-ends can both destroy vortices and turn some asters into vortices. We have shown that discrete filament-motor protein models provide new insights into the stationary and dynamical behavior of active gels and subcellular structures, because many phenomena occur on the length-scale of single filaments. Based on our findings, we argue the need for a deeper understanding of the microscopic

Developing an active emergency medical service system based on WiMAX technology.

Science.gov (United States)

Li, Shing-Han; Cheng, Kai-An; Lu, Wen-Hui; Lin, Te-Chang

2012-10-01

The population structure has changed with the aging of population. In the present, elders account for 10.63% of the domestic population and the percentage is still gradually climbing. In other words, the demand for emergency services among elders in home environment is expected to grow in the future. In order to improve the efficiency and quality of emergency care, information technology should be effectively utilized to integrate medical systems and facilities, strengthen human-centered operation designs, and maximize the overall performance. The improvement in the quality and survival rate of emergency care is an important basis for better life and health of all people. Through integrated application of medical information systems and information communication technology, this study proposes a WiMAX-based emergency care system addressing the public demands for convenience, speed, safety, and human-centered operation of emergency care. This system consists of a healthcare service center, emergency medical service hospitals, and emergency ambulances. Using the wireless transmission capability of WiMAX, patients' physiological data can be transmitted from medical measurement facilities to the emergency room and emergency room doctors can provide immediate online instructions on emergency treatment via video and audio transmission. WiMAX technology enables the establishment of active emergency medical services.

The Making of SPINdle

Science.gov (United States)

Lam, Ho-Pun; Governatori, Guido

We present the design and implementation of SPINdle - an open source Java based defeasible logic reasoner capable to perform efficient and scalable reasoning on defeasible logic theories (including theories with over 1 million rules). The implementation covers both the standard and modal extensions to defeasible logics. It can be used as a standalone theory prover and can be embedded into any applications as a defeasible logic rule engine. It allows users or agents to issues queries, on a given knowledge base or a theory generated on the fly by other applications, and automatically produces the conclusions of its consequences. The theory can also be represented using XML.

Mastering Autodesk 3ds Max 2013

CERN Document Server

Harper, Jeffrey

2012-01-01

Get professional training in 3ds Max from this Autodesk Official Training Guide Extremely popular with video game designers as well as architects, 3ds Max offers integrated 3D modeling, animation, rendering, and compositing tools designed to streamline production. If you already have a working knowledge of 3ds Max basics, this official guide will take your skills to the next level. Detailed tutorials cover all the latest features of 3ds Max. From modeling, texturing, animation, and architectural visualization to high-level techniques for film, television, games, and more, this book provides

Abnormal spindles in second meiosis in canola (Brassica napus and Brassica campestris

Directory of Open Access Journals (Sweden)

Alice Maria de Souza

1999-01-01

Full Text Available Studies were carried out on the occurrence of abnormal spindles in the second meiotic division in some canola cultivars recently introduced in Brazil. Fusion of spindles was observed in metaphase II rejoining the two sets of chromosomes segregated in anaphase I and also sequential and tripolar spindles were discovered rejoining two sets of chromatids segregated in anaphase II. The frequency of cells with abnormal spindles ranged from 3.18 to 8.10%. The results suggested that this abnormality was caused by environmental stress that affected the plants during the blooming period.O presente estudo descreve a ocorrência de fusos anormais na segunda divisão meiótica em algumas cultivares da canola recentemente introduzidas no Brasil. Fusão de fusos foi observada em metáfase II reunindo os dois conjuntos cromossômicos segregados na anáfase I; fusos sequenciais e tripolares reunindo cromátides segregadas na anáfase II também foram observados. A frequência de células com fusos anormais variou de 3,18 a 8,10% entre as variedades. Os resultados sugerem que estas anormalidades foram causadas por condições climáticas adversas que afetaram as plantas no período de florescimento. As implicações genéticas destas anormalidades são descritas.

Discrimination between micronuclei induced by spindle poisons and ...

African Journals Online (AJOL)

Discrimination between micronuclei induced by spindle poisons and clastogens by using toad bone marrow polychromatic erythrocytes. ... Egyptian Journal of Biology ... The used chemicals induced high percentages of micronuclei with variable sizes, which clarify the sensitivity of bone marrow cells of Bufo regularis to ...

Research on 3D virtual campus scene modeling based on 3ds Max and VRML

Science.gov (United States)

Kang, Chuanli; Zhou, Yanliu; Liang, Xianyue

2015-12-01

With the rapid development of modem technology, the digital information management and the virtual reality simulation technology has become a research hotspot. Virtual campus 3D model can not only express the real world objects of natural, real and vivid, and can expand the campus of the reality of time and space dimension, the combination of school environment and information. This paper mainly uses 3ds Max technology to create three-dimensional model of building and on campus buildings, special land etc. And then, the dynamic interactive function is realized by programming the object model in 3ds Max by VRML .This research focus on virtual campus scene modeling technology and VRML Scene Design, and the scene design process in a variety of real-time processing technology optimization strategy. This paper guarantees texture map image quality and improve the running speed of image texture mapping. According to the features and architecture of Guilin University of Technology, 3ds Max, AutoCAD and VRML were used to model the different objects of the virtual campus. Finally, the result of virtual campus scene is summarized.

Taking Your iPad 2 to the Max

CERN Document Server

Sadun, Erica; Sande, Steve

2011-01-01

iPad 2: It looks different. It acts different. It connects to the world, yet it is as personal as a well-worn book. And now it has two cameras!. Taking Your iPad 2 to the Max is written so that anyone can quickly get up to speed on Apple's latest hit. As bloggers at The Unofficial Apple Weblog (TUAW.com), the authors have the happy privilege of working with Apple products every day, and they'll guide you through all of the perks of being an iPad 2 owner. This book takes you from selecting and buying an iPad, to connecting it to the Internet, to using the incredible power of the iPad and all it

Dependence of US hurricane economic loss on maximum wind speed and storm size

International Nuclear Information System (INIS)

Zhai, Alice R; Jiang, Jonathan H

2014-01-01

Many empirical hurricane economic loss models consider only wind speed and neglect storm size. These models may be inadequate in accurately predicting the losses of super-sized storms, such as Hurricane Sandy in 2012. In this study, we examined the dependences of normalized US hurricane loss on both wind speed and storm size for 73 tropical cyclones that made landfall in the US from 1988 through 2012. A multi-variate least squares regression is used to construct a hurricane loss model using both wind speed and size as predictors. Using maximum wind speed and size together captures more variance of losses than using wind speed or size alone. It is found that normalized hurricane loss (L) approximately follows a power law relation with maximum wind speed (V max ) and size (R), L = 10 c V max a R b , with c determining an overall scaling factor and the exponents a and b generally ranging between 4–12 and 2–4 respectively. Both a and b tend to increase with stronger wind speed. Hurricane Sandy’s size was about three times of the average size of all hurricanes analyzed. Based on the bi-variate regression model that explains the most variance for hurricanes, Hurricane Sandy’s loss would be approximately 20 times smaller if its size were of the average size with maximum wind speed unchanged. It is important to revise conventional empirical hurricane loss models that are only dependent on maximum wind speed to include both maximum wind speed and size as predictors. (letters)

Acute effect of carbamazepine on corticothalamic 5-9-Hz and thalamocortical spindle (10-16-Hz) oscillations in the rat.

Science.gov (United States)

Zheng, Thomas W; O'Brien, Terence J; Kulikova, Sofya P; Reid, Christopher A; Morris, Margaret J; Pinault, Didier

2014-03-01

A major side effect of carbamazepine (CBZ), a drug used to treat neurological and neuropsychiatric disorders, is drowsiness, a state characterized by increased slow-wave oscillations with the emergence of sleep spindles in the electroencephalogram (EEG). We conducted cortical EEG and thalamic cellular recordings in freely moving or lightly anesthetized rats to explore the impact of CBZ within the intact corticothalamic (CT)-thalamocortical (TC) network, more specifically on CT 5-9-Hz and TC spindle (10-16-Hz) oscillations. Two to three successive 5-9-Hz waves were followed by a spindle in the cortical EEG. A single systemic injection of CBZ (20 mg/kg) induced a significant increase in the power of EEG 5-9-Hz oscillations and spindles. Intracellular recordings of glutamatergic TC neurons revealed 5-9-Hz depolarizing wave-hyperpolarizing wave sequences prolonged by robust, rhythmic spindle-frequency hyperpolarizing waves. This hybrid sequence occurred during a slow hyperpolarizing trough, and was at least 10 times more frequent under the CBZ condition than under the control condition. The hyperpolarizing waves reversed at approximately -70 mV, and became depolarizing when recorded with KCl-filled intracellular micropipettes, indicating that they were GABAA receptor-mediated potentials. In neurons of the GABAergic thalamic reticular nucleus, the principal source of TC GABAergic inputs, CBZ augmented both the number and the duration of sequences of rhythmic spindle-frequency bursts of action potentials. This indicates that these GABAergic neurons are responsible for the generation of at least the spindle-frequency hyperpolarizing waves in TC neurons. In conclusion, CBZ potentiates GABAA receptor-mediated TC spindle oscillations. Furthermore, we propose that CT 5-9-Hz waves can trigger TC spindles. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

A Fast Numerical Method for Max-Convolution and the Application to Efficient Max-Product Inference in Bayesian Networks.

Science.gov (United States)

Serang, Oliver

2015-08-01

Observations depending on sums of random variables are common throughout many fields; however, no efficient solution is currently known for performing max-product inference on these sums of general discrete distributions (max-product inference can be used to obtain maximum a posteriori estimates). The limiting step to max-product inference is the max-convolution problem (sometimes presented in log-transformed form and denoted as "infimal convolution," "min-convolution," or "convolution on the tropical semiring"), for which no O(k log(k)) method is currently known. Presented here is an O(k log(k)) numerical method for estimating the max-convolution of two nonnegative vectors (e.g., two probability mass functions), where k is the length of the larger vector. This numerical max-convolution method is then demonstrated by performing fast max-product inference on a convolution tree, a data structure for performing fast inference given information on the sum of n discrete random variables in O(nk log(nk)log(n)) steps (where each random variable has an arbitrary prior distribution on k contiguous possible states). The numerical max-convolution method can be applied to specialized classes of hidden Markov models to reduce the runtime of computing the Viterbi path from nk(2) to nk log(k), and has potential application to the all-pairs shortest paths problem.

Dynamic maintenance of asymmetric meiotic spindle position through Arp2/3 complex-driven cytoplasmic streaming in mouse oocytes

Science.gov (United States)

Yi, Kexi; Unruh, Jay R.; Deng, Manqi; Slaughter, Brian D.; Rubinstein, Boris; Li, Rong

2012-01-01

Mature mammalian oocytes are poised for the completion of second polar body extrusion upon fertilization by positioning the metaphase spindle in close proximity to an actomyosin-rich cortical cap. Loss of this spindle position asymmetry is often associated with poor oocyte quality and infertility 1–3. Here, we report a novel role for the Arp2/3 actin nucleation complex in the maintenance of asymmetric spindle position in mature mouse oocytes. The Arp2/3 complex localizes to the cortical cap in a Ran GTPase-dependent manner and accounts for the nucleation of the majority of actin filaments in both the cortical cap and a cytoplasmic actin network. Inhibition of Arp2/3 complex activity or localization leads to rapid dissociation of the spindle from the cortex. High resolution live imaging and spatiotemporal image correlation spectroscopy (STICS) analysis reveal that in normal oocytes actin filaments flow continuously away from the Arp2/3-rich cortex, generating a cytoplamic streaming that results in a net pushing force on the spindle toward the actomyosin cap. Arp2/3 inhibition not only diminishes this actin flow and cytoplamic streaming but also enables a reverse streaming driven by myosin-II-based cortical contraction, leading to spindle movement away from the cortex. We conclude that the Arp2/3 complex maintains asymmetric meiotic spindle position by generating an actin polymerization-driven cytoplamic streaming and by suppressing a counteracting force from myosin-II-based contractility. PMID:21874009

A Modeling approach for analysis and improvement of spindle-holder-tool assembly dynamics

OpenAIRE

Budak, Erhan; Ertürk, A.; Erturk, A.; Özgüven, H. N.; Ozguven, H. N.

2006-01-01

The most important information required for chatter stability analysis is the dynamics of the involved structures, i.e. the frequency response functions (FRFs) which are usually determined experimentally. In this study, the tool point FRF of a spindle-holder-tool assembly is analytically determined by using the receptance coupling and structural modification techniques. Timoshenko’s beam model is used for increased accuracy. The spindle is also modeled analytically with elastic supports repre...

Spindle disturbances in human-hamster hybrid (AL) cells induced by mobile communication frequency range signals.

Science.gov (United States)

Schrader, Thorsten; Münter, Klaus; Kleine-Ostmann, Thomas; Schmid, Ernst

2008-12-01

The production of spindle disturbances in FC2 cells, a human-hamster hybrid (A(L)) cell line, by non-ionizing radiation was studied using an electromagnetic field with a field strength of 90 V/m at a frequency of 835 MHz. Due to the given experimental conditions slide flask cultures were exposed at room temperature in a microTEM (transversal electromagnetic field) cell, which allows optimal experimental conditions for small samples of biological material. Numerical calculations suggest that specific absorption rates of up to 60 mW/kg are reached for maximum field exposure. All exposure field parameters--either measured or calculable--are precisely defined and, for the first time, traceable to the standards of the SI system of physical units. Compared with co-incident negative controls, the results of two independently performed experiments suggest that exposure periods of time from 0.5 to 2 h with an electric field strength of 90 V/m are spindle acting agents as predominately indicated by the appearance of spindle disturbances at the ana- and telophase stages (especially lagging and non-disjunction of single chromosomes) of cell divisions. The spindle disturbances do not change the fraction of mitotic cells with increasing exposure time up to 2 h. Due to the applied experimental conditions an influence of temperature as a confounder parameter for spindle disturbances can be excluded.

Tukey max-stable processes for spatial extremes

KAUST Repository

Xu, Ganggang; Genton, Marc G.

2016-01-01

We propose a new type of max-stable process that we call the Tukey max-stable process for spatial extremes. It brings additional flexibility to modeling dependence structures among spatial extremes. The statistical properties of the Tukey max

SPINDLE: A 2-Stage Nuclear-Powered Cryobot for Ocean World Exploration

Science.gov (United States)

Stone, W.; Hogan, B.; Siegel, V. L.; Howe, T.; Howe, S.; Harman, J.; Richmond, K.; Flesher, C.; Clark, E.; Lelievre, S.; Moor, J.; Rothhammer, B.

2016-12-01

SPINDLE (Sub-glacial Polar Ice Navigation, Descent, and Lake Exploration) is a 2-stage autonomous vehicle system consisting of a robotic ice-penetrating carrier vehicle (cryobot) and a marsupial, hovering autonomous underwater vehicle (HAUV). The cryobot will descend through an ice body into a sub-ice aqueous environment and deploy the HAUV to conduct long range reconnaissance, life search, and sample collection. The HAUV will return to, and auto-dock with, the cryobot at the conclusion of the mission for subsequent data uplink and sample return to the surface. The SPINDLE cryobot has been currently designed for a 1.5 kilometer penetration through a terrestrial ice sheet and the HAUV has been designed for persistent exploration and science presence in for deployments up to a kilometer radius from the cryobot. Importantly, the cryobot is bi-directional and vertically controllable both in an ice sheet as well as following breakthrough into a subglacial water cavity / ocean. The vehicle has been designed for long-duration persistent science in subglacial cavities and to allow for subsequent return-to-surface at a much later date or subsequent season. Engineering designs for the current SPINDLE cryobot will be presented in addition to current designs for autonomous rendezvous, docking, and storing of the HAUV system into the cryobot for subsequent recovery of the entire system to the surface. Taken to completion in a three-phase program, SPINDLE will deliver an integrated and field-tested system that will be directly transferable into a Flagship-class mission to either the hypothesized shallow lakes of Europa, the sub-surface ocean of Ganymede, or the geyser/plume sources on both Europa and Enceladus. We present the results of several parallel laboratory investigations into advanced power transmission systems (laser, high voltage) as well as onboard systems that enable the SPINDLE vehicle to access any subglacial lake on earth while using non-nuclear surrogate, surface

Casein kinase II is required for the spindle assembly checkpoint by regulating Mad2p in fission yeast

Energy Technology Data Exchange (ETDEWEB)

Shimada, Midori [Department of Biochemistry and Cell Biology, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Yamamoto, Ayumu [Department of Chemistry, Shizuoka University, 836 Ohya, Suruga-ku, Sizuoka 422-8529 (Japan); Murakami-Tonami, Yuko; Nakanishi, Makoto; Yoshida, Takashi [Department of Biochemistry and Cell Biology, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan); Aiba, Hirofumi [Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya 464-8601 (Japan); Murakami, Hiroshi, E-mail: hmura@med.nagoya-cu.ac.jp [Department of Biochemistry and Cell Biology, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601 (Japan)

2009-10-23

The spindle checkpoint is a surveillance mechanism that ensures the fidelity of chromosome segregation in mitosis. Here we show that fission yeast casein kinase II (CK2) is required for this checkpoint function. In the CK2 mutants mitosis occurs in the presence of a spindle defect, and the spindle checkpoint protein Mad2p fails to localize to unattached kinetochores. The CK2 mutants are sensitive to the microtubule depolymerising drug thiabendazole, which is counteracted by ectopic expression of mad2{sup +}. The level of Mad2p is low in the CK2 mutants. These results suggest that CK2 has a role in the spindle checkpoint by regulating Mad2p.

Casein kinase II is required for the spindle assembly checkpoint by regulating Mad2p in fission yeast

International Nuclear Information System (INIS)

Shimada, Midori; Yamamoto, Ayumu; Murakami-Tonami, Yuko; Nakanishi, Makoto; Yoshida, Takashi; Aiba, Hirofumi; Murakami, Hiroshi

2009-01-01

The spindle checkpoint is a surveillance mechanism that ensures the fidelity of chromosome segregation in mitosis. Here we show that fission yeast casein kinase II (CK2) is required for this checkpoint function. In the CK2 mutants mitosis occurs in the presence of a spindle defect, and the spindle checkpoint protein Mad2p fails to localize to unattached kinetochores. The CK2 mutants are sensitive to the microtubule depolymerising drug thiabendazole, which is counteracted by ectopic expression of mad2 + . The level of Mad2p is low in the CK2 mutants. These results suggest that CK2 has a role in the spindle checkpoint by regulating Mad2p.

Quantum Max-flow/Min-cut

Science.gov (United States)

Cui, Shawn X.; Freedman, Michael H.; Sattath, Or; Stong, Richard; Minton, Greg

2016-06-01

The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts of the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.

Quantum Max-flow/Min-cut

Energy Technology Data Exchange (ETDEWEB)

Cui, Shawn X., E-mail: xingshan@math.ucsb.edu [Department of Mathematics, University of California, Santa Barbara, California 93106 (United States); Quantum Architectures and Computation Group, Microsoft Research, Redmond, Washington 98052 (United States); Freedman, Michael H., E-mail: michaelf@microsoft.com [Department of Mathematics, University of California, Santa Barbara, California 93106 (United States); Microsoft Research, Station Q, University of California, Santa Barbara, California 93106 (United States); Sattath, Or, E-mail: sattath@gmail.com [Computer Science Division, University of California, Berkeley, California 94720 (United States); Stong, Richard, E-mail: stong@ccrwest.org; Minton, Greg, E-mail: gtminto@ccrwest.org [Center for Communications Research, La Jolla, California 92121 (United States)

2016-06-15

The classical max-flow min-cut theorem describes transport through certain idealized classical networks. We consider the quantum analog for tensor networks. By associating an integral capacity to each edge and a tensor to each vertex in a flow network, we can also interpret it as a tensor network and, more specifically, as a linear map from the input space to the output space. The quantum max-flow is defined to be the maximal rank of this linear map over all choices of tensors. The quantum min-cut is defined to be the minimum product of the capacities of edges over all cuts of the tensor network. We show that unlike the classical case, the quantum max-flow=min-cut conjecture is not true in general. Under certain conditions, e.g., when the capacity on each edge is some power of a fixed integer, the quantum max-flow is proved to equal the quantum min-cut. However, concrete examples are also provided where the equality does not hold. We also found connections of quantum max-flow/min-cut with entropy of entanglement and the quantum satisfiability problem. We speculate that the phenomena revealed may be of interest both in spin systems in condensed matter and in quantum gravity.

Ford C-Max plug-in hybrid; Ford C-Max mit Plug-in-Hybridtechnik

Energy Technology Data Exchange (ETDEWEB)

Schamel, Andreas; D' Annunzio, Julie; Iorio, Rob [Ford Motor Company, Dearborn, MI (United States); Schmitz, Peter [Ford-Forschungszentrum Aachen GmbH, Aachen (Germany)

2013-03-01

Ford provides consumers a broad choice of electrified vehicles globally, including full hybrids, plug-in hybrids and all-electric vehicles. The all-new 2013 model year C-Max Energi Plug-in Hybrid utilises the third generation of Ford hybrid technology. This article discusses the hybrid powersplit architecture and components, as well as the charging capability and human-machine interfaces, used in the C-Max Energi Plug-In Hybrid. (orig.)

Phosphatase-regulated recruitment of the spindle- and kinetochore-associated (Ska complex to kinetochores

Directory of Open Access Journals (Sweden)

Sushama Sivakumar

2017-11-01

Full Text Available Kinetochores move chromosomes on dynamic spindle microtubules and regulate signaling of the spindle checkpoint. The spindle- and kinetochore-associated (Ska complex, a hexamer composed of two copies of Ska1, Ska2 and Ska3, has been implicated in both roles. Phosphorylation of kinetochore components by the well-studied mitotic kinases Cdk1, Aurora B, Plk1, Mps1, and Bub1 regulate chromosome movement and checkpoint signaling. Roles for the opposing phosphatases are more poorly defined. Recently, we showed that the C terminus of Ska1 recruits protein phosphatase 1 (PP1 to kinetochores. Here we show that PP1 and protein phosphatase 2A (PP2A both promote accumulation of Ska at kinetochores. Depletion of PP1 or PP2A by siRNA reduces Ska binding at kinetochores, impairs alignment of chromosomes to the spindle midplane, and causes metaphase delay or arrest, phenotypes that are also seen after depletion of Ska. Artificial tethering of PP1 to the outer kinetochore protein Nuf2 promotes Ska recruitment to kinetochores, and it reduces but does not fully rescue chromosome alignment and metaphase arrest defects seen after Ska depletion. We propose that Ska has multiple functions in promoting mitotic progression and that kinetochore-associated phosphatases function in a positive feedback cycle to reinforce Ska complex accumulation at kinetochores.

Max dD/Dt: A Novel Parameter to Assess Fetal Cardiac Contractility and a Substitute for Max dP/Dt.

Science.gov (United States)

Fujita, Yasuyuki; Kiyokoba, Ryo; Yumoto, Yasuo; Kato, Kiyoko

2018-07-01

Aortic pulse waveforms are composed of a forward wave from the heart and a reflection wave from the periphery. We focused on this forward wave and suggested a new parameter, the maximum slope of aortic pulse waveforms (max dD/dt), for fetal cardiac contractility. Max dD/dt was calculated from fetal aortic pulse waveforms recorded with an echo-tracking system. A normal range of max dD/dt was constructed in 105 healthy fetuses using linear regression analysis. Twenty-two fetuses with suspected fetal cardiac dysfunction were divided into normal and decreased max dD/dt groups, and their clinical parameters were compared. Max dD/dt of aortic pulse waveforms increased linearly with advancing gestational age (r = 0.93). The decreased max dD/dt was associated with abnormal cardiotocography findings and short- and long-term prognosis. In conclusion, max dD/dt calculated from the aortic pulse waveforms in fetuses can substitute for max dP/dt, an index of cardiac contractility in adults. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Relations between ultrastructure of mitotic spindle and chromosome translocation

Directory of Open Access Journals (Sweden)

Jadwiga A. Tarkowska

2014-01-01

Full Text Available Dividing endosperm cells of Haemanthus katherinae Bak. treated with an 0.25 per cent mixture of water-soluble glycosides from Nerium oleander were insepected in a light microscope (LM and severe disturbances were found in all phases of mitosis. The same cells were observed in the electron microscope (EM and relations were noted and analysed between the chromosome arrangement and the submicroscopic structure of the mitotuc spindle. The successive steps in the disintegration of the formed spindle are described: fragmentatiun of all microtubules (MTs starting from the poles, disappearance of non-kinetachore MTs and further the external MTs of the kineto,chore bundle. The central (internal parallel ones remain the longest at the kinerf,ochares. Oleander glycosides cause disintegration of the existing MTs and prevent formation of new ones. The causes of restitution transformations in the successive phases of mitosis are discussed.

Investigation of Flow Behavior around Corotating Blades in a Double-Spindle Lawn Mower Deck

Directory of Open Access Journals (Sweden)

Chon W.

2005-01-01

Full Text Available When the airflow patterns inside a lawn mower deck are understood, the deck can be redesigned to be efficient and have an increased cutting ability. To learn more, a combination of computational and experimental studies was performed to investigate the effects of blade and housing designs on a flow pattern inside a 1.1m wide corotating double-spindle lawn mower deck with side discharge. For the experimental portion of the study, air velocities inside the deck were measured using a laser Doppler velocimetry (LDV system. A high-speed video camera was used to observe the flow pattern. Furthermore, noise levels were measured using a sound level meter. For the computational fluid dynamics (CFD work, several arbitrary radial sections of a two-dimensional blade were selected to study flow computations. A three-dimensional, full deck model was also developed for realistic flow analysis. The computational results were then compared with the experimental results.

Sleep spindle alterations in patients with Parkinson's disease

DEFF Research Database (Denmark)

Christensen, Julie Anja Engelhard; Nikolic, Miki; Warby, Simon C.

2015-01-01

The aim of this study was to identify changes of sleep spindles (SS) in the EEG of patients with Parkinson's disease (PD). Five sleep experts manually identified SS at a central scalp location (C3-A2) in 15 PD and 15 age- and sex-matched control subjects. Each SS was given a confidence score...

Combined classical spindle cell/pleomorphic lipoma spectrum imaging and clinical data

Energy Technology Data Exchange (ETDEWEB)

Younan, Yara; Gonzalez, Felix; Umpierrez, Monica; Singer, Adam D. [Emory University Hospital, Department of Radiology and Imaging Sciences Section of Musculoskeletal Imaging, Atlanta, GA (United States); Martinez, Anthony; Edgar, Mark [Emory University Hospital, Department of Pathology, Atlanta, GA (United States); Reimer, Nickolas [Emory University Hospital, Department of Orthopedic Surgery, Atlanta, GA (United States); Subhawong, Ty [University of Miami, Department of Radiology, Miami, FL (United States)

2018-01-15

Compile the largest study to date on the imaging and clinical features of the classic spindle cell/pleomorphic lipoma spectrum and suggest this diagnosis be included in the differential for benign and malignant macroscopic fat-containing soft tissue masses regardless of the mass location or patient demographics. An institutional search was performed to identify all available classic-type spindle cell/pleomorphic lipomas with available demographic and imaging data. Images and reports were analyzed by one MSK-trained radiologist and radiographic, anatomic and clinical data were recorded. Additionally, a literature search was performed to identify studies describing the spindle cell lipoma spectrum imaging features and were combined with institutional data. Forty-two institutional cases were identified, 37 of which had MRIs performed among which 21 had images available (T1- and T2-weighted pulse sequences) for review while the remainder had outside reports detailing the mass imaging features. There was a mean age of 57 with 79% of cases occurring in males. Contrary to prior reports, 57% of masses were subcutaneous, and the neck and back region accounted for 26% of cases. When the institutional cases were combined with available data in the literature, there was a new sample size of 91 masses, 74 of which had MRI and/or CT data. Eighty-seven percent of masses were heterogeneous, 51% were composed of less than 75% fat, 65% were in the back, neck or shoulder region, 27% of masses were deep and 91% demonstrated enhancement. Eighty-two percent of patients were males with a mean age of 58 at excision. Imaging features, patient demographics and tumor location alone are not enough to differentiate tumors of the spindle cell lipoma spectrum from other macroscopic fat-containing benign and malignant tumors, and these entities should be included in the same imaging differential diagnosis. (orig.)

Lateralised sleep spindles relate to false memory generation.

Science.gov (United States)

Shaw, John J; Monaghan, Padraic

2017-12-01

Sleep is known to enhance false memories: After presenting participants with lists of semantically related words, sleeping before recalling these words results in a greater acceptance of unseen "lure" words related in theme to previously seen words. Furthermore, the right hemisphere (RH) seems to be more prone to false memories than the left hemisphere (LH). In the current study, we investigated the sleep architecture associated with these false memory and lateralisation effects in a nap study. Participants viewed lists of related words, then stayed awake or slept for approximately 90min, and were then tested for recognition of previously seen-old, unseen-new, or unseen-lure words presented either to the LH or RH. Sleep increased acceptance of unseen-lure words as previously seen compared to the wake group, particularly for RH presentations of word lists. RH lateralised stage 2 sleep spindle density relative to the LH correlated with this increase in false memories, suggesting that RH sleep spindles enhanced false memories in the RH. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cenp-meta is required for sustained spindle checkpoint

Directory of Open Access Journals (Sweden)

Thomas Rubin

2014-05-01

Full Text Available Cenp-E is a kinesin-like motor protein required for efficient end-on attachment of kinetochores to the spindle microtubules. Cenp-E immunodepletion in Xenopus mitotic extracts results in the loss of mitotic arrest and massive chromosome missegregation, whereas its depletion in mammalian cells leads to chromosome segregation defects despite the presence of a functional spindle assembly checkpoint (SAC. Cenp-meta has previously been reported to be the Drosophila homolog of vertebrate Cenp-E. In this study, we show that cenp-metaΔ mutant neuroblasts arrest in mitosis when treated with colchicine. cenp-metaΔ mutant cells display a mitotic delay. Yet, despite the persistence of the two checkpoint proteins Mad2 and BubR1 on unattached kinetochores, these cells eventually enter anaphase and give rise to highly aneuploid daughter cells. Indeed, we find that cenp-metaΔ mutant cells display a slow but continuous degradation of cyclin B, which eventually triggers the mitotic exit observed. Thus, our data provide evidence for a role of Cenp-meta in sustaining the SAC response.

In-situ hot corrosion testing of candidate materials for exhaust valve spindles

DEFF Research Database (Denmark)

Bihlet, Uffe; Hoeg, Harro A.; Dahl, Kristian Vinter

2011-01-01

The two stroke diesel engine has been continually optimized since its invention more than a century ago. One of the ways to increase fuel efficiency further is to increase the compression ratio, and thereby the temperature in the combustion chamber. Because of this, and the composition of the fuel...... used, exhaust valve spindles in marine diesel engines are subjected to high temperatures and stresses as well as molten salt induced corrosion. To investigate candidate materials for future designs which will involve the HIP process, a spindle with Ni superalloy material samples inserted in a HIPd Ni49...

Abnormal spindle orientation during microsporogenesis in an interspecific Brachiaria (Gramineae hybrid

Directory of Open Access Journals (Sweden)

Andréa Beatriz Mendes-Bonato

2006-01-01

Full Text Available This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into focused poles due to parallel spindle fibers. As a consequence, in telophase I, an elongated nucleus or several micronuclei were observed in each pole. In the second division, the behavior was the same, leading to polyads with several micronuclei. A total of 40% of meiotic products were affected. The use of this hybrid in production systems needing good-quality seeds is discussed.

The Drosophila Microtubule-Associated Protein Mars Stabilizes Mitotic Spindles by Crosslinking Microtubules through Its N-Terminal Region

DEFF Research Database (Denmark)

Zhang, Gang; Beati, Hamze; Nilsson, Jakob

2013-01-01

Correct segregation of genetic material relies on proper assembly and maintenance of the mitotic spindle. How the highly dynamic microtubules (MTs) are maintained in stable mitotic spindles is a key question to be answered. Motor and non-motor microtubule associated proteins (MAPs) have been...

WiMax network planning and optimization

CERN Document Server

Zhang, Yan

2009-01-01

This book offers a comprehensive explanation on how to dimension, plan, and optimize WiMAX networks. The first part of the text introduces WiMAX networks architecture, physical layer, standard, protocols, security mechanisms, and highly related radio access technologies. It covers system framework, topology, capacity, mobility management, handoff management, congestion control, medium access control (MAC), scheduling, Quality of Service (QoS), and WiMAX mesh networks and security. Enabling easy understanding of key concepts and technologies, the second part presents practical examples and illu

IL-6 and mouse oocyte spindle.

Directory of Open Access Journals (Sweden)

Jashoman Banerjee

Full Text Available Interleukin 6 (IL-6 is considered a major indicator of the acute-phase inflammatory response. Endometriosis and pelvic inflammation, diseases that manifest elevated levels of IL-6, are commonly associated with higher infertility. However, the mechanistic link between elevated levels of IL-6 and poor oocyte quality is still unclear. In this work, we explored the direct role of this cytokine as a possible mediator for impaired oocyte spindle and chromosomal structure, which is a critical hurdle in the management of infertility. Metaphase-II mouse oocytes were exposed to recombinant mouse IL-6 (50, 100 and 200 ng/mL for 30 minutes and subjected to indirect immunofluorescent staining to identify alterations in the microtubule and chromosomal alignment compared to untreated controls. The deterioration in microtubule and chromosomal alignment were evaluated utilizing both fluorescence and confocal microscopy, and were quantitated with a previously reported scoring system. Our results showed that IL-6 caused a dose-dependent deterioration in microtubule and chromosomal alignment in the treated oocytes as compared to the untreated group. Indeed, IL-6 at a concentration as low as 50 ng/mL caused deterioration in the spindle structure in 60% of the oocytes, which increased significantly (P<0.0001 as IL-6 concentration was increased. In conclusion, elevated levels of IL-6 associated with endometriosis and pelvic inflammation may reduce the fertilizing capacity of human oocyte through a mechanism that involves impairment of the microtubule and chromosomal structure.

Spindles and active vortices in a model of confined filament-motor mixtures

Directory of Open Access Journals (Sweden)

Head David A

2011-11-01

Full Text Available Abstract Background Robust self-organization of subcellular structures is a key principle governing the dynamics and evolution of cellular life. In fission yeast cells undergoing division, the mitotic spindle spontaneously emerges from the interaction of microtubules, motor proteins and the confining cell walls, and asters and vortices have been observed to self-assemble in quasi-two dimensional microtubule-kinesin assays. There is no clear microscopic picture of the role of the active motors driving this pattern formation, and the relevance of continuum modeling to filament-scale structures remains uncertain. Results Here we present results of numerical simulations of a discrete filament-motor protein model confined to a pressurised cylindrical box. Stable spindles, nematic configurations, asters and high-density semi-asters spontaneously emerge, the latter pair having also been observed in cytosol confined within emulsion droplets. State diagrams are presented delineating each stationary state as the pressure, motor speed and motor density are varied. We further highlight a parameter regime where vortices form exhibiting collective rotation of all filaments, but have a finite life-time before contracting to a semi-aster. Quantifying the distribution of life-times suggests this contraction is a Poisson process. Equivalent systems with fixed volume exhibit persistent vortices with stochastic switching in the direction of rotation, with switching times obeying similar statistics to contraction times in pressurised systems. Furthermore, we show that increasing the detachment rate of motors from filament plus-ends can both destroy vortices and turn some asters into vortices. Conclusions We have shown that discrete filament-motor protein models provide new insights into the stationary and dynamical behavior of active gels and subcellular structures, because many phenomena occur on the length-scale of single filaments. Based on our findings, we argue

Gas flow through the clearances of screw spindle vacuum pumps; Gasspaltstroemungen in Schraubenspindel-Vakuumpumpen

Energy Technology Data Exchange (ETDEWEB)

Kauder, K.; Wenderott, D. [Dortmund Univ. (Germany). FG Fluidenergiemaschinen

1998-12-31

The documentation `Schraubenmaschinen` deals with the subject `screw spindle vacuum pump` for the first time. Therefore, this paper presents the type of maschine `screw spindle vacuum pump`, fixes its limits to the better known screw type compressor and finally classifies it in the crossover of vacuum-technology, characteristic geometry and the numerical simulation. The suggested reflections to choose a proper model of flow are based on the geometry of the screw spindle vacuum pump and fundamentals concerning the vacuum-technology and the state of flow. (orig.) [Deutsch] Die Schriftenreihe `Schraubenmaschinen` behandelt erstmals das Thema `Schraubenspindel-Vakuumpumpe`. Aus diesem Grund stellt der vorliegende Beitrag den Maschinentyp Schraubenspindel-Vakuumpumpe vor, grenzt ihn zur bekannteren Schraubenmaschine ab und ordnet ihn in der Schnittmenge aus Vakuumtechnik, charakteristischer Maschinengeometrie und der Simulation ein. Auf den vakuumtechnischen und stroemungstechnischen Grundlagen sowie geometrischen Betrachtungen basieren die genannten Ueberlegungen zur Auswahl geeigneter Stroemungsmodelle. (orig.)

Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

Science.gov (United States)

Capra, N F; Ro, J Y

2000-05-01

The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the

Distribution of TTX-sensitive voltage-gated sodium channels in primary sensory endings of mammalian muscle spindles.

Science.gov (United States)

Carrasco, Dario I; Vincent, Jacob A; Cope, Timothy C

2017-04-01

Knowledge of the molecular mechanisms underlying signaling of mechanical stimuli by muscle spindles remains incomplete. In particular, the ionic conductances that sustain tonic firing during static muscle stretch are unknown. We hypothesized that tonic firing by spindle afferents depends on sodium persistent inward current (INaP) and tested for the necessary presence of the appropriate voltage-gated sodium (NaV) channels in primary sensory endings. The NaV 1.6 isoform was selected for both its capacity to produce INaP and for its presence in other mechanosensors that fire tonically. The present study shows that NaV 1.6 immunoreactivity (IR) is concentrated in heminodes, presumably where tonic firing is generated, and we were surprised to find NaV 1.6 IR strongly expressed also in the sensory terminals, where mechanotransduction occurs. This spatial pattern of NaV 1.6 IR distribution was consistent for three mammalian species (rat, cat, and mouse), as was tonic firing by primary spindle afferents. These findings meet some of the conditions needed to establish participation of INaP in tonic firing by primary sensory endings. The study was extended to two additional NaV isoforms, selected for their sensitivity to TTX, excluding TTX-resistant NaV channels, which alone are insufficient to support firing by primary spindle endings. Positive immunoreactivity was found for NaV 1.1 , predominantly in sensory terminals together with NaV 1.6 and for NaV 1.7 , mainly in preterminal axons. Differential distribution in primary sensory endings suggests specialized roles for these three NaV isoforms in the process of mechanosensory signaling by muscle spindles. NEW & NOTEWORTHY The molecular mechanisms underlying mechanosensory signaling responsible for proprioceptive functions are not completely elucidated. This study provides the first evidence that voltage-gated sodium channels (NaVs) are expressed in the spindle primary sensory ending, where NaVs are found at every site

Nicotine-induced Disturbances of Meiotic Maturation in Cultured Mouse Oocytes: Alterations of Spindle Integrity and Chromosome Alignment

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Zenzes Maria

2004-09-01

Full Text Available Abstract We investigated whether nicotine exposure in vitro of mouse oocytes affects spindle and chromosome function during meiotic maturation (M-I and M-II. Oocytes in germinal vesicle (GV stage were cultured in nicotine for 8 h or for 16 h, to assess effects in M-I and in metaphase II (M-II. The latter culture setting used the three protocols: 8 h nicotine then 8 h medium (8N + 8M; 16 h nicotine (16N; 8 h medium then 8 h nicotine (8M + 8N. Non-toxic concentrations of nicotine at 1.0, 2.5, 5.0 and 10.0 mmol/L were used. Spindle-chromosome configurations were analyzed with wide-field optical sectioning microscopy. In 8 h cultures, nicotine exposure resulted in dose-related increased proportions of M-I oocytes with defective spindle-chromosome configurations. A dose-related delayed entry into anaphase I was also detected. In 16 h cultures, nicotine exposure for the first 8 h (8N + 8M, or for 16 h (16N, resulted in dose- and time-related increased proportions of oocytes arrested in M-I (10 mmol/L; 8 h: 53.2%, controls 9.6%; 16 h: 87.6%, controls 8.5%. Defects in M-I spindles and chromosomes caused M-I arrest leading to dose-related decreased proportions of oocytes that reached metaphase-II (10 mmol/L 8 h: 46.8%, controls 90.4%;16 h: 12.4%, controls 91.5%. A delayed anaphase-I affected the normal timing of M-II, leading to abnormal oocytes with dispersed chromosomes, or with double spindles and no polar body. Nicotine exposure during the second 8 h (8M + 8N resulted in dose-related, increased proportions of M-II oocytes with defective spindles and chromosomes (10 mmol/L: 42.9%, controls 2.0%. Nicotine has no adverse effects on GV break down, but induces spindle and chromosome defects compromising oocyte meiotic maturation and development.

Nek2A destruction marks APC/C activation at the prophase-to-prometaphase transition by spindle-checkpoint-restricted Cdc20.

Science.gov (United States)

Boekhout, Michiel; Wolthuis, Rob

2015-04-15

Nek2 isoform A (Nek2A) is a presumed substrate of the anaphase-promoting complex/cyclosome containing Cdc20 (APC/C(Cdc20)). Nek2A, like cyclin A, is degraded in mitosis while the spindle checkpoint is active. Cyclin A prevents spindle checkpoint proteins from binding to Cdc20 and is recruited to the APC/C in prometaphase. We found that Nek2A and cyclin A avoid being stabilized by the spindle checkpoint in different ways. First, enhancing mitotic checkpoint complex (MCC) formation by nocodazole treatment inhibited the degradation of geminin and cyclin A, whereas Nek2A disappeared at a normal rate. Second, depleting Cdc20 effectively stabilized cyclin A but not Nek2A. Nevertheless, Nek2A destruction crucially depended on Cdc20 binding to the APC/C. Third, in contrast to cyclin A, Nek2A was recruited to the APC/C before the start of mitosis. Interestingly, the spindle checkpoint very effectively stabilized an APC/C-binding mutant of Nek2A, which required the Nek2A KEN box. Apparently, in cells, the spindle checkpoint primarily prevents Cdc20 from binding destruction motifs. Nek2A disappearance marks the prophase-to-prometaphase transition, when Cdc20, regardless of the spindle checkpoint, activates the APC/C. However, Mad2 depletion accelerated Nek2A destruction, showing that spindle checkpoint release further increases APC/C(Cdc20) catalytic activity. © 2015. Published by The Company of Biologists Ltd.

Computational Model for Impact-Resisting Critical Thickness of High-Speed Machine Outer Protective Plate

Science.gov (United States)

Wu, Huaying; Wang, Li Zhong; Wang, Yantao; Yuan, Xiaolei

2018-05-01

The blade or surface grinding blade of the hypervelocity grinding wheel may be damaged due to too high rotation rate of the spindle of the machine and then fly out. Its speed as a projectile may severely endanger the field persons. Critical thickness model of the protective plate of the high-speed machine is studied in this paper. For easy analysis, the shapes of the possible impact objects flying from the high-speed machine are simplified as sharp-nose model, ball-nose model and flat-nose model. Whose front ending shape to represent point, line and surface contacting. Impact analysis based on J-C model is performed for the low-carbon steel plate with different thicknesses in this paper. One critical thickness computational model for the protective plate of high-speed machine is established according to the damage characteristics of the thin plate to get relation among plate thickness and mass, shape and size and impact speed of impact object. The air cannon is used for impact test. The model accuracy is validated. This model can guide identification of the thickness of single-layer outer protective plate of a high-speed machine.

Inhibition of clathrin by pitstop 2 activates the spindle assembly checkpoint and induces cell death in dividing HeLa cancer cells

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Smith Charlotte M

2013-01-01

Full Text Available Abstract Background During metaphase clathrin stabilises the mitotic spindle kinetochore(K-fibres. Many anti-mitotic compounds target microtubule dynamics. Pitstop 2™ is the first small molecule inhibitor of clathrin terminal domain and inhibits clathrin-mediated endocytosis. We investigated its effects on a second function for clathrin in mitosis. Results Pitstop 2 did not impair clathrin recruitment to the spindle but disrupted its function once stationed there. Pitstop 2 trapped HeLa cells in metaphase through loss of mitotic spindle integrity and activation of the spindle assembly checkpoint, phenocopying clathrin depletion and aurora A kinase inhibition. Conclusions Pitstop 2 is therefore a new tool for investigating clathrin spindle dynamics. Pitstop 2 reduced viability in dividing HeLa cells, without affecting dividing non-cancerous NIH3T3 cells, suggesting that clathrin is a possible novel anti-mitotic drug target.

Tukey max-stable processes for spatial extremes

KAUST Repository

Xu, Ganggang

2016-09-21

We propose a new type of max-stable process that we call the Tukey max-stable process for spatial extremes. It brings additional flexibility to modeling dependence structures among spatial extremes. The statistical properties of the Tukey max-stable process are demonstrated theoretically and numerically. Simulation studies and an application to Swiss rainfall data indicate the effectiveness of the proposed process. © 2016 Elsevier B.V.

Approximation by max-product type operators

CERN Document Server

Bede, Barnabás; Gal, Sorin G

2016-01-01

This monograph presents a broad treatment of developments in an area of constructive approximation involving the so-called "max-product" type operators. The exposition highlights the max-product operators as those which allow one to obtain, in many cases, more valuable estimates than those obtained by classical approaches. The text considers a wide variety of operators which are studied for a number of interesting problems such as quantitative estimates, convergence, saturation results, localization, to name several. Additionally, the book discusses the perfect analogies between the probabilistic approaches of the classical Bernstein type operators and of the classical convolution operators (non-periodic and periodic cases), and the possibilistic approaches of the max-product variants of these operators. These approaches allow for two natural interpretations of the max-product Bernstein type operators and convolution type operators: firstly, as possibilistic expectations of some fuzzy variables, and secondly,...

OaMAX2 of Orobanche aegyptiaca and Arabidopsis AtMAX2 share conserved functions in both development and drought responses.

Science.gov (United States)

Li, Weiqiang; Nguyen, Kien Huu; Watanabe, Yasuko; Yamaguchi, Shinjiro; Tran, Lam-Son Phan

2016-09-16

Previous studies in Arabidopsis reported that the MAX2 (more axillary growth 2) gene is a component of the strigolactone (SL) signaling pathway, which regulates a wide range of biological processes, from plant growth and development to environmental stress responses. Orobanche aegyptiaca is a harmful parasitic plant for many economically important crops. Seed germination of O. aegyptiaca is very sensitive to SLs, suggesting that O. aegyptiaca may contain components of the SL signaling pathway. To investigate this hypothesis, we identified and cloned a MAX2 ortholog from O. aegyptiaca for complementation analyses using the Arabidopsis Atmax2 mutant. The so-called OaMAX2 gene could rescue phenotypes of the Atmax2 mutant in various tested developmental aspects, including seed germination, shoot branching, leaf senescence and growth and development of hypocotyl, root hair, primary root and lateral root. More importantly, OaMAX2 could enhance the drought tolerance of Atmax2 mutant, suggesting its ability to restore the drought-tolerant phenotype of mutant plants defected in AtMAX2 function. Thus, this study provides genetic evidence that the functions of the MAX2 orthologs, and perhaps the MAX2 signaling pathways, are conserved in parasitic and non-parasitic plants. Furthermore, the results of our study enable us to develop a strategy to fight against parasitic plants by suppressing the MAX signaling, which ultimately leads to enhanced productivity of crop plants. Copyright © 2016 Elsevier Inc. All rights reserved.

MAX Provider Characteristics

Data.gov (United States)

U.S. Department of Health & Human Services — The MAX Provider Characteristics (PC) File Implementation Report describes the design, implementation, and results of the MAXPC prototype, which was based on three...

Glucose assisted synthesis of hollow spindle LiMnPO_4/C nanocomposites for high performance Li-ion batteries

International Nuclear Information System (INIS)

Fu, Xiaoning; Chang, Zhaorong; Chang, Kun; Li, Bao; Tang, Hongwei; Shangguan, Enbo; Yuan, Xiao-Zi; Wang, Haijiang

2015-01-01

Graphical abstract: Nano-sized hollow spindle LiMnPO_4 with a well-developed olivine-type structure exhibits a high specific capacity and cycling performance. - Highlights: • A pure and well-crystallized LiMnPO_4 are synthesized via a solution-phase method. • The LiMnPO_4/C composite constitutes highly and uniformly distributed hollow spindles. • The LiMnPO_4/C composite exhibits a high specific capacity and cycling performance. • The growth process of the hollow spindle LiMnPO_4 particles is revealed. - Abstract: Nano-sized hollow spindle LiMnPO_4 with a well-developed olivine-type structure was synthesized with the assistance of glucose in dimethyl sulfoxide (DMSO)/H_2O under ambient pressure and 108 °C. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images show that the LiMnPO_4 particles consist of hollow spindles with a mean width of 200 nm, length of 500-700 nm, and wall thickness of about 30-60 nm. The LiMnPO_4/C nanocomposite was obtained by sintering nano-sized LiMnPO_4 with glucose at 650 °C under an inert atmosphere for 4 h. With a coated carbon thickness of about 10 nm, the obtained composite maintained the morphology and size of the hollow spindle. The electrochemical tests show the specific capacity of LiMnPO_4/C nanocomposite is 161.8 mAh g"−"1 at 0.05C, 137.7 mAh g"−"1 at 0.1C and 110.8 mAh g"−"1 at 0.2 C. The retention of discharge capacity maintains 92% after 100 cycles at 0.2 C. After different rate cycles the high capacity of the LiMnPO_4/C nanocomposite can be recovered. This high performance is attributed to the composite material's hollow spindle structure, which facilitates the electrolyte infiltration, resulting in an increased solid-liquid interface. The carbon layer covering the hollow spindle also contributes to the high performance of the LiMnPO_4/C material as the carbon layer improves its electronic conductivity and the nano-scaled wall thickness decreases the paths of Li

Primary histiocytic sarcoma arising in the head and neck with predominant spindle cell component

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Zhao XF

2007-02-01

Full Text Available Abstract This is the first case report of Histiocytic Sarcoma (HS with predominant spindle cell component occurring in the head and neck region of a 41-year-old man. The tumor was composed of sheets of large round to oval cells with pleomorphic vesicular nuclei, prominent nucleoli and abundant eosinophilic cytoplasm. Multinucleated forms, numerous mitoses, and tumor necrosis were also noted. Sheets, fascicles, and whorls of spindle cells with spindled to ovoid vesicular nuclei, small to medium-sized distinct nucleoli, and eosinophilic cytoplasm were frequently observed. Immunohistochemical staining in the tumor cells was positive for CD163, CD68, lysozyme, CD45, and NSE. Focal expression of CD4 and S-100 was also noted. Electron microscopy demonstrated an abundance of lysosomes in the cytoplasm of tumor cells. Chromosome study revealed a 57–80 hyperdiploid [7]/46, XY [13] karyotype, including 3 to 4 copies of various chromosomes. The immunohistochemical and ultrastructural findings confirmed the diagnosis of HS.

Mitotic Spindle Asymmetry: A Wnt/PCP-Regulated Mechanism Generating Asymmetrical Division in Cortical Precursors

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Delphine Delaunay

2014-01-01

Full Text Available The regulation of asymmetric cell division (ACD during corticogenesis is incompletely understood. We document that spindle-size asymmetry (SSA between the two poles occurs during corticogenesis and parallels ACD. SSA appears at metaphase and is maintained throughout division, and we show it is necessary for proper neurogenesis. Imaging of spindle behavior and division outcome reveals that neurons preferentially arise from the larger-spindle pole. Mechanistically, SSA magnitude is controlled by Wnt7a and Vangl2, both members of the Wnt/planar cell polarity (PCP-signaling pathway, and relayed to the cell cortex by P-ERM proteins. In vivo, Vangl2 and P-ERM downregulation promotes early cell-cycle exit and prevents the proper generation of late-born neurons. Thus, SSA is a core component of ACD that is conserved in invertebrates and vertebrates and plays a key role in the tight spatiotemporal control of self-renewal and differentiation during mammalian corticogenesis.

Introducing Autodesk 3ds Max 2011

CERN Document Server

Derakhshani, Dariush

2010-01-01

An Autodesk Official Training Guide to 3ds Max 2011. 3ds Max is a popular 3D animation-and-effects software used in movies, visual effects, games, cartoons, short films, commercials, and other animation. However, it also presents a number of challenges to newcomers. This introduction to the latest version breaks down the complexities of learning 3D software and walks you through the basics of modeling, texturing, animating, and using visual effects. Real-world examples from talented beginning 3ds max users motivate you to learn the software and helpful tutorials offer realistic, professional c

Interplay between microtubule bundling and sorting factors ensures acentriolar spindle stability during C. elegans oocyte meiosis.

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Timothy J Mullen

2017-09-01

Full Text Available In many species, oocyte meiosis is carried out in the absence of centrioles. As a result, microtubule organization, spindle assembly, and chromosome segregation proceed by unique mechanisms. Here, we report insights into the principles underlying this specialized form of cell division, through studies of C. elegans KLP-15 and KLP-16, two highly homologous members of the kinesin-14 family of minus-end-directed kinesins. These proteins localize to the acentriolar oocyte spindle and promote microtubule bundling during spindle assembly; following KLP-15/16 depletion, microtubule bundles form but then collapse into a disorganized array. Surprisingly, despite this defect we found that during anaphase, microtubules are able to reorganize into a bundled array that facilitates chromosome segregation. This phenotype therefore enabled us to identify factors promoting microtubule organization during anaphase, whose contributions are normally undetectable in wild-type worms; we found that SPD-1 (PRC1 bundles microtubules and KLP-18 (kinesin-12 likely sorts those bundles into a functional orientation capable of mediating chromosome segregation. Therefore, our studies have revealed an interplay between distinct mechanisms that together promote spindle formation and chromosome segregation in the absence of structural cues such as centrioles.

Spindle-like thalamocortical synchronization in a rat brain slice preparation.

Science.gov (United States)

Tancredi, V; Biagini, G; D'Antuono, M; Louvel, J; Pumain, R; Avoli, M

2000-08-01

We obtained rat brain slices (550-650 microm) that contained part of the frontoparietal cortex along with a portion of the thalamic ventrobasal complex (VB) and of the reticular nucleus (RTN). Maintained reciprocal thalamocortical connectivity was demonstrated by VB stimulation, which elicited orthodromic and antidromic responses in the cortex, along with re-entry of thalamocortical firing originating in VB neurons excited by cortical output activity. In addition, orthodromic responses were recorded in VB and RTN following stimuli delivered in the cortex. Spontaneous and stimulus-induced coherent rhythmic oscillations (duration = 0.4-3.5 s; frequency = 9-16 Hz) occurred in cortex, VB, and RTN during application of medium containing low concentrations of the K(+) channel blocker 4-aminopyridine (0.5-1 microM). This activity, which resembled electroencephalograph (EEG) spindles recorded in vivo, disappeared in both cortex and thalamus during application of the excitatory amino acid receptor antagonist kynurenic acid in VB (n = 6). By contrast, cortical application of kynurenic acid (n = 4) abolished spindle-like oscillations at this site, but not those recorded in VB, where their frequency was higher than under control conditions. Our findings demonstrate the preservation of reciprocally interconnected cortical and thalamic neuron networks that generate thalamocortical spindle-like oscillations in an in vitro rat brain slice. As shown in intact animals, these oscillations originate in the thalamus where they are presumably caused by interactions between RTN and VB neurons. We propose that this preparation may help to analyze thalamocortical synchronization and to understand the physiopathogenesis of absence attacks.

Sleep spindle and K-complex detection using tunable Q-factor wavelet transform and morphological component analysis

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Tarek eLajnef

2015-07-01

Full Text Available A novel framework for joint detection of sleep spindles and K-complex events, two hallmarks of sleep stage S2, is proposed. Sleep electroencephalography (EEG signals are split into oscillatory (spindles and transient (K-complex components. This decomposition is conveniently achieved by applying morphological component analysis (MCA to a sparse representation of EEG segments obtained by the recently introduced discrete tunable Q-factor wavelet transform (TQWT. Tuning the Q-factor provides a convenient and elegant tool to naturally decompose the signal into an oscillatory and a transient component. The actual detection step relies on thresholding (i the transient component to reveal K-complexes and (ii the time-frequency representation of the oscillatory component to identify sleep spindles. Optimal thresholds are derived from ROC-like curves (sensitivity versus FDR on training sets and the performance of the method is assessed on test data sets. We assessed the performance of our method using full-night sleep EEG data we collected from 14 participants. In comparison to visual scoring (Expert 1, the proposed method detected spindles with a sensitivity of 83.18% and false discovery rate (FDR of 39%, while K-complexes were detected with a sensitivity of 81.57% and an FDR of 29.54%. Similar performances were obtained when using a second expert as benchmark. In addition, when the TQWT and MCA steps were excluded from the pipeline the detection sensitivities dropped down to 70% for spindles and to 76.97% for K-complexes, while the FDR rose up to 43.62% and 49.09% respectively. Finally, we also evaluated the performance of the proposed method on a set of publicly available sleep EEG recordings. Overall, the results we obtained suggest that the TQWT-MCA method may be a valuable alternative to existing spindle and K-complex detection methods. Paths for improvements and further validations with large-scale standard open-access benchmarking data sets are

A Balance between Nuclear and Cytoplasmic Volumes Controls Spindle Length

Czech Academy of Sciences Publication Activity Database

Nováková, Lucia; Kovačovicová, Kristina; Dang-Nguyen, T.; Šodek, Martin; Škultéty, M.; Anger, Martin

2016-01-01

Roč. 11, č. 2 (2016), e0149535-e0149535 E-ISSN 1932-6203 R&D Projects: GA ČR GAP502/12/2201 Institutional support: RVO:67985904 Keywords : mitotoc spindle * size * cells Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.806, year: 2016

Regulation of mitotic spindle formation by the RhoA guanine nucleotide exchange factor ARHGEF10

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Satoh Takaya

2009-07-01

Full Text Available Abstract Background The Dbl family guanine nucleotide exchange factor ARHGEF10 was originally identified as the product of the gene associated with slowed nerve-conduction velocities of peripheral nerves. However, the function of ARHGEF10 in mammalian cells is totally unknown at a molecular level. ARHGEF10 contains no distinctive functional domains except for tandem Dbl homology-pleckstrin homology and putative transmembrane domains. Results Here we show that RhoA is a substrate for ARHGEF10. In both G1/S and M phases, ARHGEF10 was localized in the centrosome in adenocarcinoma HeLa cells. Furthermore, RNA interference-based knockdown of ARHGEF10 resulted in multipolar spindle formation in M phase. Each spindle pole seems to contain a centrosome consisting of two centrioles and the pericentriolar material. Downregulation of RhoA elicited similar phenotypes, and aberrant mitotic spindle formation following ARHGEF10 knockdown was rescued by ectopic expression of constitutively activated RhoA. Multinucleated cells were not increased upon ARHGEF10 knockdown in contrast to treatment with Y-27632, a specific pharmacological inhibitor for the RhoA effector kinase ROCK, which induced not only multipolar spindle formation, but also multinucleation. Therefore, unregulated centrosome duplication rather than aberration in cytokinesis may be responsible for ARHGEF10 knockdown-dependent multipolar spindle formation. We further isolated the kinesin-like motor protein KIF3B as a binding partner of ARHGEF10. Knockdown of KIF3B again caused multipolar spindle phenotypes. The supernumerary centrosome phenotype was also observed in S phase-arrested osteosarcoma U2OS cells when the expression of ARHGEF10, RhoA or KIF3B was abrogated by RNA interference. Conclusion Collectively, our results suggest that a novel RhoA-dependent signaling pathway under the control of ARHGEF10 has a pivotal role in the regulation of the cell division cycle. This pathway is not involved in

Mechanisms for focusing mitotic spindle poles by minus end-directed motor proteins.

Science.gov (United States)

Goshima, Gohta; Nédélec, François; Vale, Ronald D

2005-10-24

During the formation of the metaphase spindle in animal somatic cells, kinetochore microtubule bundles (K fibers) are often disconnected from centrosomes, because they are released from centrosomes or directly generated from chromosomes. To create the tightly focused, diamond-shaped appearance of the bipolar spindle, K fibers need to be interconnected with centrosomal microtubules (C-MTs) by minus end-directed motor proteins. Here, we have characterized the roles of two minus end-directed motors, dynein and Ncd, in such processes in Drosophila S2 cells using RNA interference and high resolution microscopy. Even though these two motors have overlapping functions, we show that Ncd is primarily responsible for focusing K fibers, whereas dynein has a dominant function in transporting K fibers to the centrosomes. We also report a novel localization of Ncd to the growing tips of C-MTs, which we show is mediated by the plus end-tracking protein, EB1. Computer modeling of the K fiber focusing process suggests that the plus end localization of Ncd could facilitate the capture and transport of K fibers along C-MTs. From these results and simulations, we propose a model on how two minus end-directed motors cooperate to ensure spindle pole coalescence during mitosis.

German science. Max Planck charts new path.

Science.gov (United States)

Koenig, R

2000-06-09

Germany's premier basic research organization, the Max Planck Society, released a long-awaited blueprint for change during its annual meeting this week, recommending that the society's nearly 3000 scientists embrace more interdisciplinary and international projects in a range of new research priorities. The report, called Max Planck 2000-Plus, is the product of an 18-month-long internal review. Its recommendations were formulated by some two dozen Max Planck researchers and administrators, who sought input from every institute.

Experimental and Mathematical Modeling for Prediction of Tool Wear on the Machining of Aluminium 6061 Alloy by High Speed Steel Tools

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Okokpujie Imhade Princess

2017-12-01

Full Text Available In recent machining operation, tool life is one of the most demanding tasks in production process, especially in the automotive industry. The aim of this paper is to study tool wear on HSS in end milling of aluminium 6061 alloy. The experiments were carried out to investigate tool wear with the machined parameters and to developed mathematical model using response surface methodology. The various machining parameters selected for the experiment are spindle speed (N, feed rate (f, axial depth of cut (a and radial depth of cut (r. The experiment was designed using central composite design (CCD in which 31 samples were run on SIEG 3/10/0010 CNC end milling machine. After each experiment the cutting tool was measured using scanning electron microscope (SEM. The obtained optimum machining parameter combination are spindle speed of 2500 rpm, feed rate of 200 mm/min, axial depth of cut of 20 mm, and radial depth of cut 1.0mm was found out to achieved the minimum tool wear as 0.213 mm. The mathematical model developed predicted the tool wear with 99.7% which is within the acceptable accuracy range for tool wear prediction.

Experimental and Mathematical Modeling for Prediction of Tool Wear on the Machining of Aluminium 6061 Alloy by High Speed Steel Tools

Science.gov (United States)

Okokpujie, Imhade Princess; Ikumapayi, Omolayo M.; Okonkwo, Ugochukwu C.; Salawu, Enesi Y.; Afolalu, Sunday A.; Dirisu, Joseph O.; Nwoke, Obinna N.; Ajayi, Oluseyi O.

2017-12-01

In recent machining operation, tool life is one of the most demanding tasks in production process, especially in the automotive industry. The aim of this paper is to study tool wear on HSS in end milling of aluminium 6061 alloy. The experiments were carried out to investigate tool wear with the machined parameters and to developed mathematical model using response surface methodology. The various machining parameters selected for the experiment are spindle speed (N), feed rate (f), axial depth of cut (a) and radial depth of cut (r). The experiment was designed using central composite design (CCD) in which 31 samples were run on SIEG 3/10/0010 CNC end milling machine. After each experiment the cutting tool was measured using scanning electron microscope (SEM). The obtained optimum machining parameter combination are spindle speed of 2500 rpm, feed rate of 200 mm/min, axial depth of cut of 20 mm, and radial depth of cut 1.0mm was found out to achieved the minimum tool wear as 0.213 mm. The mathematical model developed predicted the tool wear with 99.7% which is within the acceptable accuracy range for tool wear prediction.

v-Src causes delocalization of Mklp1, Aurora B, and INCENP from the spindle midzone during cytokinesis failure

Energy Technology Data Exchange (ETDEWEB)

Soeda, Shuhei [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Nakayama, Yuji, E-mail: nakayama@mb.kyoto-phu.ac.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414 (Japan); Honda, Takuya; Aoki, Azumi; Tamura, Naoki; Abe, Kohei; Fukumoto, Yasunori [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan); Yamaguchi, Naoto, E-mail: nyama@faculty.chiba-u.jp [Department of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chuo-ku, Chiba 260-8675 (Japan)

2013-06-10

Src-family tyrosine kinases are aberrantly activated in cancers, and this activation is associated with malignant tumor progression. v-Src, encoded by the v-src transforming gene of the Rous sarcoma virus, is a mutant variant of the cellular proto-oncogene c-Src. Although investigations with temperature sensitive mutants of v-Src have shown that v-Src induces many oncogenic processes, the effects on cell division are unknown. Here, we show that v-Src inhibits cellular proliferation of HCT116, HeLa S3 and NIH3T3 cells. Flow cytometry analysis indicated that inducible expression of v-Src results in an accumulation of 4N cells. Time-lapse analysis revealed that binucleation is induced through the inhibition of cytokinesis, a final step of cell division. The localization of Mklp1, which is essential for cytokinesis, to the spindle midzone is inhibited in v-Src-expressing cells. Intriguingly, Aurora B, which regulates Mklp1 localization at the midzone, is delocalized from the spindle midzone and the midbody but not from the metaphase chromosomes upon v-Src expression. Mklp2, which is responsible for the relocation of Aurora B from the metaphase chromosomes to the spindle midzone, is also lost from the spindle midzone. These results suggest that v-Src inhibits cytokinesis through the delocalization of Mklp1 and Aurora B from the spindle midzone, resulting in binucleation. -- Highlights: • v-Src inhibits cell proliferation of HCT116, HeLa S3 and NIH3T3 cells. • v-Src induces binucleation together with cytokinesis failure. • v-Src causes delocalization of Mklp1, Aurora B and INCENP from the spindle midzone.

Effects of Heart Rate vs. Speed-Based High Intensity Interval Training on Aerobic and Anaerobic Capacity of Female Soccer Players

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Hamid Arazi

2017-08-01

Full Text Available The purpose of this study was to compare the effects of two types of high-intensity interval training (HIIT programs on aerobic and anaerobic capacity of female soccer players. Regional-level female athletes were randomly divided into heart rate-based HIIT (n = 8; age 23.4 ± 1.1 year and speed-based HIIT groups (n = 8; age 23.4 ± 1.3 year. Athletes trained three days per week for six weeks. Before and after training, each athlete’s performance was assessed directly through the Hoff test, 30-15 Intermittent Fitness Test (VIFT, and repeated-sprint ability test (RAST; maximal oxygen consumption (VO2max, power and fatigue were estimated indirectly. Both experimental groups improved power, fatigue index and VO2max after training (p < 0.05. It was noteworthy that the speed-based group had greater gains in minimal power (effect size (ES: 3.99 vs. 0.75, average power (ES: 2.23 vs. 0.33, and fatigue index (ES: 2.53 vs. 0.17 compared to heart rate-based group (p < 0.05. In conclusion, both heart rate-based and speed-based HIIT induced meaningful improvements in power, VO2max, and fatigue index in female soccer players, although the speed-based HIIT group achieved greater gains in power and fatigue index compared to the heart rate-based group.

Structures of actin-like ParM filaments show architecture of plasmid-segregating spindles.

Science.gov (United States)

Bharat, Tanmay A M; Murshudov, Garib N; Sachse, Carsten; Löwe, Jan

2015-07-02

Active segregation of Escherichia coli low-copy-number plasmid R1 involves formation of a bipolar spindle made of left-handed double-helical actin-like ParM filaments. ParR links the filaments with centromeric parC plasmid DNA, while facilitating the addition of subunits to ParM filaments. Growing ParMRC spindles push sister plasmids to the cell poles. Here, using modern electron cryomicroscopy methods, we investigate the structures and arrangements of ParM filaments in vitro and in cells, revealing at near-atomic resolution how subunits and filaments come together to produce the simplest known mitotic machinery. To understand the mechanism of dynamic instability, we determine structures of ParM filaments in different nucleotide states. The structure of filaments bound to the ATP analogue AMPPNP is determined at 4.3 Å resolution and refined. The ParM filament structure shows strong longitudinal interfaces and weaker lateral interactions. Also using electron cryomicroscopy, we reconstruct ParM doublets forming antiparallel spindles. Finally, with whole-cell electron cryotomography, we show that doublets are abundant in bacterial cells containing low-copy-number plasmids with the ParMRC locus, leading to an asynchronous model of R1 plasmid segregation.

ELA-max: A new topical lidocaine formulation.

Science.gov (United States)

Goldman, Ran D

2004-05-01

To evaluate the role of a new formulation of lidocaine (ELA-max) in local anesthesia in children and compare it with the eutectic mixture of local anesthetics (EMLA). Relevant literature was identified by a MEDLINE search (1966-November 2003) using the search terms ELA-max and EMLA. Bibliographies of selected articles were also examined to include all relevant investigations. The product manufacturer was contacted for inclusion of the most recent data available. Topical anesthesia in children is clinically challenging. ELA-max has been shown to be as effective as EMLA for venipuncture in children, but with faster onset. Adverse effects, such as transient blanching with redness and erythema, have been reported. Further investigation is needed to determine the effectiveness of ELA-max on other painful procedures in children, as well as its safety.

Exact simulation of max-stable processes.

Science.gov (United States)

Dombry, Clément; Engelke, Sebastian; Oesting, Marco

2016-06-01

Max-stable processes play an important role as models for spatial extreme events. Their complex structure as the pointwise maximum over an infinite number of random functions makes their simulation difficult. Algorithms based on finite approximations are often inexact and computationally inefficient. We present a new algorithm for exact simulation of a max-stable process at a finite number of locations. It relies on the idea of simulating only the extremal functions, that is, those functions in the construction of a max-stable process that effectively contribute to the pointwise maximum. We further generalize the algorithm by Dieker & Mikosch (2015) for Brown-Resnick processes and use it for exact simulation via the spectral measure. We study the complexity of both algorithms, prove that our new approach via extremal functions is always more efficient, and provide closed-form expressions for their implementation that cover most popular models for max-stable processes and multivariate extreme value distributions. For simulation on dense grids, an adaptive design of the extremal function algorithm is proposed.

One-pot synthesis and electrochemical reactivity of carbon coated LiFePO4 spindles

International Nuclear Information System (INIS)

Yu Juanjuan; Hu Juncheng; Li Jinlin

2012-01-01

Highlights: ► Carbon coated LiFePO 4 spindles have been successfully synthesized via a novel supercritical method. ► The concentrations of lithium have an effect on the morphology of carbon coated LiFePO 4 . ► Amorphous carbon layer formed on the surface of LiFePO 4 by adding glucose. ► The carbon coating is responsible for the enhanced electrochemical performance. - Abstract: Spindle-like carbon coated LiFePO 4 (LiFePO 4 /C) composites have been successfully synthesized via a novel one-pot supercritical methanol method. The products were characterized by X-ray power diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). The particle size, morphology and electrochemical reactivity changed with the concentration of lithium and carbon source. A possible morphology evolution process was also proposed. The glucose not only facilitates the formation of single crystalline LiFePO 4 , but also gives an amorphous carbon layer on the surface LiFePO 4 spindles.

Medicaid Analytic eXtract (MAX) General Information

Data.gov (United States)

U.S. Department of Health & Human Services — The Medicaid Analytic eXtract (MAX) data is a set of person-level data files on Medicaid eligibility, service utilization, and payments. The MAX data are created to...

Max Jakobson õiendab arveid ajalooga / Imbi Paju

Index Scriptorium Estoniae

Paju, Imbi, 1959-

2003-01-01

Soome politoloogi ja diplomaadi Max Jakobsoni raamatust "Tilinpäätos" ("Arve sulgemine"), milles ta käsitleb Eesti ja Soome suhteid 20. sajandil. Vt samas: Lennart Meri meelitas Jakobsoni sõjakuritegusid uurima; lühiintervjuu Max Jakobsoniga

Veteranpoliitik Max Jakobson õpetab ajalugu / Sirje Kiin

Index Scriptorium Estoniae

Kiin, Sirje, 1949-

1998-01-01

Soome sõltumatu välispoliitika konsultant ja ajakirjanik Max Jakobson. Ülevaade Max Jakobsoni intervjuust soomerootsi majandusajakirjale "Forum för ekonomi och teknik" 1998. aasta aprillinumbris Venemaa Baltimaade-vastasest propagandast ning EL-i ja NATO laienemisest

Max Planck and modern physics

International Nuclear Information System (INIS)

Hoffmann, Dieter

2010-01-01

Max Planck (1858-1947) is according to the words of Max von Laue the ''father of quantum physics''. This characteristic has until today continuance, although Planck stood for long time sceptically in front of his quantum hypothesis and so became a revolutionary in spite of his wishes. Eclipted by this pioneer role of the scholar for the foundation of the quantum theory are the numerous further works of the scholer, by which he has in many other fields provided eminent things. Starting with his fundamental contribution to thermodynamics, which make him to an excellent researcher of the field, until the works in the early history of relativity theory and the promotion of the young Einstein, which let him become also to a pioneer of the second central pillar of modern physics. The present collection attempts to show the whole spectrum of the physical works of Max Planck and his role in the formation of modern physics. [de

Pengaturan Kecepatan Motor Spindle pada Retrofit Mesin Bubut CNC Menggunakan Kontroler PID Gain Scheduling

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Fikri Yoga Permana

2013-03-01

Full Text Available Pada mesin bubut Computerized Numerical Control (CNC, proses pemahatan benda kerja memerlukan kecepatan potong yang tetap agar hasil kerja memiliki tingkat presisi tinggi. Dalam prakteknya, ketika terjadi pemotongan, diameter benda kerja akan selalu berkurang dan tingkat kedalaman pahat berubah-ubah sesuai dengan proses yang dilakukan sehingga mempengaruhi kecepatan putar motor spindle sehingga mengakibatkan tingkat presisi hasil kerja menjadi berkurang. Pada penelitian ini, digunakan kontroler PI Gain Scheduling untuk mengatur kecapatan motor spindle. Hasil yang didapatkan berupa simulasi kontroler PI Gain Scheduling. Dari hasil simulasi didapatkan kontroler PI Gain Scheduling mampu membuat respon sistem sesuai dengan yang diinginkan.

"Fast" and "slow" skeleto-fusimotor innervation in cat tenuissimus spindles; a study with the glycogen-depletion method.

Science.gov (United States)

Jami, L; Lan-Couton, D; Malmgren, K; Petit, J

1978-07-01

The glycogen-depletion method was used to investigate the motor supply to tenuissimus with respect to the presence of fast beta axons and to assess the total proportion of both fast and slow beta-innervated spindles in this muscle. In a first series of 5 expts., groups of motor axons with conduction velocities higher than 85 m/s were repetitively stimulated so as to produce glycogen depletion in the muscle fibres they innervated. The whole muscle was then quick-frozen, serially cut, stained to demonstrate glycogen and examined for intrafusal glycogen depletion. Zones of glycogen depletion were found in 16 of the 46 examined spindles; they were most frequently located in the longest of the chain intrafusal muscle fibres. Since it is known that there are no purely fusimotor axons to tenuissimus with conduction velocities above 50 m/s, it was concluded that beta axons are present among the fastest axons to this muscle. In a second series of 5 expts. as many motor axons as possible with conduction velocities above 60 m/s were stimulated. Zones of glycogen depletion were found in 19 of the 47 examined spindles. They affected chain fibres in about half of the instances and bag1 fibers in the others. As this latter location is characteristic of slow dynamic beta axons, it was concluded that both slow and fast beta axons occur regularly in the motor supply to tenuissimus. beta-innervation is present in at least 40% of tenuissimus spindles with almost no convergence of fast and slow beta axons onto the same spindle.

Inhibition of muscle spindle afferent activity during masseter muscle fatigue in the rat.

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Brunetti, Orazio; Della Torre, Giovannella; Lucchi, Maria Luisa; Chiocchetti, Roberto; Bortolami, Ruggero; Pettorossi, Vito Enrico

2003-09-01

The influence of muscle fatigue on the jaw-closing muscle spindle activity has been investigated by analyzing: (1) the field potentials evoked in the trigeminal motor nucleus (Vmot) by trigeminal mesencephalic nucleus (Vmes) stimulation, (2) the orthodromic and antidromic responses evoked in the Vmes by stimulation of the peripheral and central axons of the muscle proprioceptive afferents, and (3) the extracellular unitary discharge of masseter muscle spindles recorded in the Vmes. The masseter muscle was fatigued by prolonged tetanic masseter nerve electrical stimulation. Pre- and postsynaptic components of the potentials evoked in the Vmot showed a significant reduction in amplitude following muscle fatigue. Orthodromic and antidromic potentials recorded in the Vmes also showed a similar amplitude decrease. Furthermore, muscle fatigue caused a decrease of the discharge frequency of masseter muscle spindle afferents in most of the examined units. The inhibition of the potential amplitude and discharge frequency was strictly correlated with the extent of muscle fatigue and was mediated by the group III and IV afferent muscle fibers activated by fatigue. In fact, the inhibitory effect was abolished by capsaicin injection in the masseter muscle that provokes selective degeneration of small afferent muscle fibers containing neurokinins. We concluded that fatigue signals originating from the muscle and traveling through capsaicin-sensitive fibers are able to diminish the proprioceptive input by a central presynaptic influence. In the second part of the study, we examined the central projection of the masseter small afferents sensitive to capsaicin at the electron-microscopic level. Fiber degeneration was induced by injecting capsaicin into the masseter muscle. Degenerating terminals were found on the soma and stem process in Vmes and on the dendritic tree of neurons in Vmot. This suggests that small muscle afferents may influence the muscle spindle activity through

Muscle spindles exhibit core lesions and extensive degeneration of intrafusal fibers in the Ryr1I4895T/wt mouse model of core myopathy

International Nuclear Information System (INIS)

Zvaritch, Elena; MacLennan, David H.

2015-01-01

Muscle spindles from the hind limb muscles of adult Ryr1 I4895T/wt (IT/+) mice exhibit severe structural abnormalities. Up to 85% of the spindles are separated from skeletal muscle fascicles by a thick layer of connective tissue. Many intrafusal fibers exhibit degeneration, with Z-line streaming, compaction and collapse of myofibrillar bundles, mitochondrial clumping, nuclear shrinkage and pyknosis. The lesions resemble cores observed in the extrafusal myofibers of this animal model and of core myopathy patients. Spindle abnormalities precede those in extrafusal fibers, indicating that they are a primary pathological feature in this murine Ryr1-related core myopathy. Muscle spindle involvement, if confirmed for human core myopathy patients, would provide an explanation for an array of devastating clinical features characteristic of these diseases and provide novel insights into the pathology of RYR1-related myopathies. - Highlights: • Muscle spindles exhibit structural abnormalities in a mouse model of core myopathy. • Myofibrillar collapse and mitochondrial clumping is observed in intrafusal fibers. • Myofibrillar degeneration follows a pattern similar to core formation in extrafusal myofibers. • Muscle spindle abnormalities are a part of the pathological phenotype in the mouse model of core myopathy. • Direct involvement of muscle spindles in the pathology of human RYR1-related myopathies is proposed

Topography of Slow Sigma Power during Sleep is Associated with Processing Speed in Preschool Children.

Science.gov (United States)

Doucette, Margaret R; Kurth, Salome; Chevalier, Nicolas; Munakata, Yuko; LeBourgeois, Monique K

2015-11-04

Cognitive development is influenced by maturational changes in processing speed, a construct reflecting the rapidity of executing cognitive operations. Although cognitive ability and processing speed are linked to spindles and sigma power in the sleep electroencephalogram (EEG), little is known about such associations in early childhood, a time of major neuronal refinement. We calculated EEG power for slow (10-13 Hz) and fast (13.25-17 Hz) sigma power from all-night high-density electroencephalography (EEG) in a cross-sectional sample of healthy preschool children (n = 10, 4.3 ± 1.0 years). Processing speed was assessed as simple reaction time. On average, reaction time was 1409 ± 251 ms; slow sigma power was 4.0 ± 1.5 μV²; and fast sigma power was 0.9 ± 0.2 μV². Both slow and fast sigma power predominated over central areas. Only slow sigma power was correlated with processing speed in a large parietal electrode cluster (p power predicted faster reaction time. Our findings indicate regional correlates between sigma power and processing speed that are specific to early childhood and provide novel insights into the neurobiological features of the EEG that may underlie developing cognitive abilities.

Deterministic algorithms for multi-criteria Max-TSP

NARCIS (Netherlands)

Manthey, Bodo

2012-01-01

We present deterministic approximation algorithms for the multi-criteria maximum traveling salesman problem (Max-TSP). Our algorithms are faster and simpler than the existing randomized algorithms. We devise algorithms for the symmetric and asymmetric multi-criteria Max-TSP that achieve ratios of

Spindle Cell Carcinoma of Nasal Cavity- A Case Report

Science.gov (United States)

Mittal, Abhishek; Nagpal, Tapan

2016-01-01

Spindle Cell Carcinoma (SpCC), also known as Sarcomatoid Carcinoma, is a rare and peculiar biphasic malignant neoplasm that occurs mainly in the upper aero-digestive tract, mostly in larynx. SCC accounts for 3% of all squamous cell carcinomas (SCCs) in the head and neck region. It is a rare variant of SCC which shows spindled or pleomorphic tumour cells simulating a true sarcoma. We present a case report of SpCC nasal cavity in a 50-year-old female patient, presented with intermittent epistaxis from left nasal cavity. On physical examination, the patient had an ulcero-exophytic type of mass in the left nasal cavity and a smooth bulge on the left side of anterior hard palate. Patient underwent excision of nasal mass along with partial palatectomy by facial degloving approach and reconstruction of palate with naso-labial flap. The postoperative histopathological report showed SCC. Surgery forms the mainstay of treatment. Radiotherapy and Chemotherapy is warranted in order to improve treatment results. As only few cases have been reported, we report a case of this rare entity to contribute for better understanding and awareness of this rare malignancy. PMID:27190843

Spindle-cell squamous carcinoma of the esophagus: a tumor with biphasic morphology

International Nuclear Information System (INIS)

Agha, F.P.; Keren, D.F.

1985-01-01

Spindle-cell squamous carcinoma of the esophagus is a rare malignant tumor. It is characterized by a large bulky mass in the middle third of the esophagus with a lobulated surface and local expansion of the esophagus. This lesion may be pedunculated and cause relatively little obstruction despite its bulk. The current view, based on ultrastructure and immunohistochemical evidence, has confirmed that the sarcomatous component of the squamous cell carcinoma originates from mesenchymal metaplasia of squamous cells. On the basis of this evidence and clinical behavior, it seems appropriate to consider carcinosarcoma and pseudosarcoma as equivalents and as variants of squamous cell carcinoma. Four patients with spindle-cell squamous carcinoma, an unusual subset of squamous carcinoma, are described, and the salient radiographic and pathologic features of this disorder's distinctive biphasic morphology are discussed

Novel Approaches to Enhance Mobile WiMAX Security

Directory of Open Access Journals (Sweden)

Taeshik Shon

2010-01-01

Full Text Available The IEEE 802.16 Working Group on Broadband Wireless Access Standards released IEEE 802.16-2004 which is a standardized technology for supporting broadband and wireless communication with fixed and nomadic access. After the IEEE 802.16-2004 standard, a new advanced and revised standard was released as the IEEE 802.16e-2005 amendment which is foundation of Mobile WiMAX network supporting handover and roaming capabilities. In the area of security aspects, compared to IEEE 802.16-2004, IEEE 802.16e, called Mobile WiMAX, adopts improved security architecture—PKMv2 which includes EAP authentication, AES-based authenticated encryption, and CMAC or HMAC message protection. However, there is no guarantee that PKMv2-based Mobile WiMAX network will not have security flaws. In this paper, we investigate the current Mobile WiMAX security architecture focusing mainly on pointing out new security vulnerabilities such as a disclosure of security context in network entry, a lack of secure communication in network domain, and a necessity of efficient handover supporting mutual authentication. Based on the investigation results, we propose a novel Mobile WiMAX security architecture, called RObust and Secure MobilE WiMAX (ROSMEX, to prevent the new security vulnerabilities.

Sleep spindles during a nap correlate with post sleep memory performance for highly rewarded word-pairs.

Science.gov (United States)

Studte, Sara; Bridger, Emma; Mecklinger, Axel

2017-04-01

The consolidation of new associations is thought to depend in part on physiological processes engaged during non-REM (NREM) sleep, such as slow oscillations and sleep spindles. Moreover, NREM sleep is thought to selectively benefit associations that are adaptive for the future. In line with this, the current study investigated whether different reward cues at encoding are associated with changes in sleep physiology and memory retention. Participants' associative memory was tested after learning a list of arbitrarily paired words both before and after taking a 90-min nap. During learning, word-pairs were preceded by a cue indicating either a high or a low reward for correct memory performance at test. The motivation manipulation successfully impacted retention such that memory declined to a greater extent from pre- to post sleep for low rewarded than for high rewarded word-pairs. In line with previous studies, positive correlations between spindle density during NREM sleep and general memory performance pre- and post-sleep were found. In addition to this, however, a selective positive relationship between memory performance for highly rewarded word-pairs at posttest and spindle density during NREM sleep was also observed. These results support the view that motivationally salient memories are preferentially consolidated and that sleep spindles may be an important underlying mechanism for selective consolidation. Copyright © 2016 Elsevier Inc. All rights reserved.

Improvements of ModalMax High-Fidelity Piezoelectric Audio Device

Science.gov (United States)

Woodard, Stanley E.

2005-01-01

ModalMax audio speakers have been enhanced by innovative means of tailoring the vibration response of thin piezoelectric plates to produce a high-fidelity audio response. The ModalMax audio speakers are 1 mm in thickness. The device completely supplants the need to have a separate driver and speaker cone. ModalMax speakers can perform the same applications of cone speakers, but unlike cone speakers, ModalMax speakers can function in harsh environments such as high humidity or extreme wetness. New design features allow the speakers to be completely submersed in salt water, making them well suited for maritime applications. The sound produced from the ModalMax audio speakers has sound spatial resolution that is readily discernable for headset users.

WiMAX network performance monitoring & optimization

DEFF Research Database (Denmark)

Zhang, Qi; Dam, H

2008-01-01

frequency reuse, capacity planning, proper network dimensioning, multi-class data services and so on. Furthermore, as a small operator we also want to reduce the demand for sophisticated technicians and man labour hours. To meet these critical demands, we design a generic integrated network performance......In this paper we present our WiMAX (worldwide interoperability for microwave access) network performance monitoring and optimization solution. As a new and small WiMAX network operator, there are many demanding issues that we have to deal with, such as limited available frequency resource, tight...... this integrated network performance monitoring and optimization system in our WiMAX networks. This integrated monitoring and optimization system has such good flexibility and scalability that individual function component can be used by other operators with special needs and more advanced function components can...

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

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N. V. Dhandapani

2015-01-01

Full Text Available This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process.

Science.gov (United States)

Dhandapani, N V; Thangarasu, V S; Sureshkannan, G

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

Max plus at work modeling and analysis of synchronized systems a course on max-plus algebra and its applications

CERN Document Server

Heidergott, Bernd; van der Woude, Jacob

2014-01-01

Trains pull into a railroad station and must wait for each other before leaving again in order to let passengers change trains. How do mathematicians then calculate a railroad timetable that accurately reflects their comings and goings? One approach is to use max-plus algebra, a framework used to model Discrete Event Systems, which are well suited to describe the ordering and timing of events. This is the first textbook on max-plus algebra, providing a concise and self-contained introduction to the topic. Applications of max-plus algebra abound in the world around us. Traffic systems, compu

Maximum Range of a Projectile Thrown from Constant-Speed Circular Motion

Science.gov (United States)

Poljak, Nikola

2016-01-01

The problem of determining the angle ? at which a point mass launched from ground level with a given speed v[subscript 0] will reach a maximum distance is a standard exercise in mechanics. There are many possible ways of solving this problem, leading to the well-known answer of ? = p/4, producing a maximum range of D[subscript max] = v[superscript…

Sleep spindles: a physiological marker of age-related changes in gray matter in brain regions supporting motor skill memory consolidation.

Science.gov (United States)

Fogel, Stuart; Vien, Catherine; Karni, Avi; Benali, Habib; Carrier, Julie; Doyon, Julien

2017-01-01

Sleep is necessary for the optimal consolidation of procedural learning, and in particular, for motor sequential skills. Motor sequence learning remains intact with age, but sleep-dependent consolidation is impaired, suggesting that memory deficits for procedural skills are specifically impacted by age-related changes in sleep. Age-related changes in spindles may be responsible for impaired motor sequence learning consolidation, but the morphological basis for this deficit is unknown. Here, we found that gray matter in the hippocampus and cerebellum was positively correlated with both sleep spindles and offline improvements in performance in young participants but not in older participants. These results suggest that age-related changes in gray matter in the hippocampus relate to spindles and may underlie age-related deficits in sleep-related motor sequence memory consolidation. In this way, spindles can serve as a biological marker for structural brain changes and the related memory deficits in older adults. Copyright © 2016 Elsevier Inc. All rights reserved.

LOX is a novel mitotic spindle-associated protein essential for mitosis.

Science.gov (United States)

Boufraqech, Myriem; Wei, Darmood; Weyemi, Urbain; Zhang, Lisa; Quezado, Martha; Kalab, Petr; Kebebew, Electron

2016-05-17

LOX regulates cancer progression in a variety of human malignancies. It is overexpressed in aggressive cancers and higher expression of LOX is associated with higher cancer mortality. Here, we report a new function of LOX in mitosis. We show that LOX co-localizes to mitotic spindles from metaphase to telophase, and p-H3(Ser10)-positive cells harbor strong LOX staining. Further, purification of mitotic spindles from synchronized cells show that LOX fails to bind to microtubules in the presence of nocodazole, whereas paclitaxel treated samples showed enrichment in LOX expression, suggesting that LOX binds to stabilized microtubules. LOX knockdown leads to G2/M phase arrest; reduced p-H3(Ser10), cyclin B1, CDK1, and Aurora B. Moreover, LOX knockdown significantly increased sensitivity of cancer cells to chemotherapeutic agents that target microtubules. Our findings suggest that LOX has a role in cancer cell mitosis and may be targeted to enhance the activity of microtubule inhibitors for cancer therapy.

Asymmetric Centriole Numbers at Spindle Poles Cause Chromosome Missegregation in Cancer

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Marco R. Cosenza

2017-08-01

Full Text Available Chromosomal instability is a hallmark of cancer and correlates with the presence of extra centrosomes, which originate from centriole overduplication. Overduplicated centrioles lead to the formation of centriole rosettes, which mature into supernumerary centrosomes in the subsequent cell cycle. While extra centrosomes promote chromosome missegregation by clustering into pseudo-bipolar spindles, the contribution of centriole rosettes to chromosome missegregation is unknown. We used multi-modal imaging of cells with conditional centriole overduplication to show that mitotic rosettes in bipolar spindles frequently harbor unequal centriole numbers, leading to biased chromosome capture that favors binding to the prominent pole. This results in chromosome missegregation and aneuploidy. Rosette mitoses lead to viable offspring and significantly contribute to progeny production. We further show that centrosome abnormalities in primary human malignancies frequently consist of centriole rosettes. As asymmetric centriole rosettes generate mitotic errors that can be propagated, rosette mitoses are sufficient to cause chromosome missegregation in cancer.

The Aurora B kinase in chromosome biorientation and spindle checkpoint signalling

Directory of Open Access Journals (Sweden)

Veronica eKrenn

2015-10-01

Full Text Available Aurora B, a member of the Aurora family of serine/threonine protein kinases, is a key player in chromosome segregation. As part of a macromolecular complex known as the chromosome passenger complex, Aurora B concentrates early during mitosis in the proximity of centromeres and kinetochores, the sites of attachment of chromosomes to spindle microtubules. There, it contributes to a number of processes that impart fidelity to cell division, including kinetochore stabilization, kinetochore-microtubule attachment, and the regulation of a surveillance mechanism named the spindle assembly checkpoint. In the regulation of these processes, Aurora B is the fulcrum of a remarkably complex network of interactions that feed back on its localization and activation state. In this review we discuss the multiple roles of Aurora B during mitosis, focusing in particular on its role at centromeres and kinetochores. Many details of the network of interactions at these locations remain poorly understood, and we focus here on several crucial outstanding questions.

FLECH PowerMax Service Requirement Specification

DEFF Research Database (Denmark)

It is expected that in the future, ancillary services will be required at distribution level. This work describes how one of these ancillary services, the PowerMax service, must be spec ified within a market framework. The basis of this work is the Flexibility Clearing House (FLE CH) platform...... and the Distribution System Operator (DSO) services defined in [1]. The PowerMax service has been further discussed in [2], and this technical report seeks to clarify the implementation details first discussed in that paper. The aim of the PowerMax service it to relieve congestion issue s in the distribution system...... by establishing a maximum power that a cluster of consumer devices may draw from the syste m. The consumers will receive a payment for providing this service, and the DSO will be able to postpone grid reinfo rcement...

Max Jakobson : Kommunismisse tuleb suhtuda objektiivselt / Max Jakobson ; interv. Kai Tänavsuu

Index Scriptorium Estoniae

Jakobson, Max, 1923-2013

2002-01-01

Inimsusevastaste Kuritegude Uurimise Rahvusvahelise Komisjoni esimees Max Jakobson oma suhtumisest talle Maarjamaa Risti I klassi teenetemärgi andmisse, tema juhitava komisjoni tööst, eestlaste püüdlusest ühineda NATOga, kommunismi ja natsismi hukkamõistust

MAX and Survey Linkages

Data.gov (United States)

U.S. Department of Health & Human Services — CMS is interested in linking MAX files with survey data, including four surveys conducted by the National Center for Health Statistics (NCHS) - the National Health...

EFHC1, a protein mutated in juvenile myoclonic epilepsy, associates with the mitotic spindle through its N-terminus

International Nuclear Information System (INIS)

Nijs, Laurence de; Lakaye, Bernard; Coumans, Bernard; Leon, Christine; Ikeda, Takashi; Delgado-Escueta, Antonio V.; Grisar, Thierry; Chanas, Grazyna

2006-01-01

A novel gene, EFHC1, mutated in juvenile myoclonic epilepsy (JME) encodes a protein with three DM10 domains of unknown function and one putative EF-hand motif. To study the properties of EFHC1, we expressed EGFP-tagged protein in various cell lines. In interphase cells, the fusion protein was present in the cytoplasm and in the nucleus with specific accumulation at the centrosome. During mitosis EGFP-EFHC1 colocalized with the mitotic spindle, especially at spindle poles and with the midbody during cytokinesis. Using a specific antibody, we demonstrated the same distribution of the endogenous protein. Deletion analyses revealed that the N-terminal region of EFHC1 is crucial for the association with the mitotic spindle and the midbody. Our results suggest that EFHC1 could play an important role during cell division

Multipolar spindle pole coalescence is a major source of kinetochore mis-attachment and chromosome mis-segregation in cancer cells.

Directory of Open Access Journals (Sweden)

William T Silkworth

Full Text Available Many cancer cells display a CIN (Chromosome Instability phenotype, by which they exhibit high rates of chromosome loss or gain at each cell cycle. Over the years, a number of different mechanisms, including mitotic spindle multipolarity, cytokinesis failure, and merotelic kinetochore orientation, have been proposed as causes of CIN. However, a comprehensive theory of how CIN is perpetuated is still lacking. We used CIN colorectal cancer cells as a model system to investigate the possible cellular mechanism(s underlying CIN. We found that CIN cells frequently assembled multipolar spindles in early mitosis. However, multipolar anaphase cells were very rare, and live-cell experiments showed that almost all CIN cells divided in a bipolar fashion. Moreover, fixed-cell analysis showed high frequencies of merotelically attached lagging chromosomes in bipolar anaphase CIN cells, and higher frequencies of merotelic attachments in multipolar vs. bipolar prometaphases. Finally, we found that multipolar CIN prometaphases typically possessed gamma-tubulin at all spindle poles, and that a significant fraction of bipolar metaphase/early anaphase CIN cells possessed more than one centrosome at a single spindle pole. Taken together, our data suggest a model by which merotelic kinetochore attachments can easily be established in multipolar prometaphases. Most of these multipolar prometaphase cells would then bi-polarize before anaphase onset, and the residual merotelic attachments would produce chromosome mis-segregation due to anaphase lagging chromosomes. We propose this spindle pole coalescence mechanism as a major contributor to chromosome instability in cancer cells.

THE RELATIONSHIP BETWEEN AEROBIC POWER AND REPEATED SPRINT ABILITY IN YOUNG SOCCER PLAYERS WITH DIFFERENT LEVELS OF VO2 MAX

Directory of Open Access Journals (Sweden)

Rostam Alizadeh

2010-06-01

Full Text Available In some team sports such as soccer which is interval, athletes need to prepare themselves immediatelyfor the next activity. Therefore it is very important to have enough information on characteristics of recovery phase and quick recovery to the first situation and to have the minimum speed reduction. The purpose of this study was to determine the relationship between aerobic power and repeated sprint ability (RSA or decrementindex in young soccer players in three different levels of Vo2max. Methods: For this reason 41 volunteers were divided in to three groups with different levels of Vo2max ml.kg-1.min-1 low 37.22 ± 2.3 (n= 18, age 17.1 ± 0.9 year, height 170.6 ± 0.76 cm, weight 67.1 ± 5.05 kg medium 46.46± 1.97 ml.kg-1.min-1 (n= 13, age 17.6± 0.76year, height 173.8 ± 4.84 cm, weight 65.9 ± 4.92 kg and high 55.63 ± 1.52 ml.kg-1.min-1 (n=10, age 17.4 ±0.69 year, height 177 ± 3.23 cm, weight 71.4 ± 3.94 kg. To determine Vo2max a graded exercise test until volitional exhaustion on treadmill was used, and also RAST was used to measure RSA. The lactate accumulation was measured before and after RSA protocol. Pearson's correlation was used to determine the correlation between the aerobic power and RSA. The results indicated that there are significant relationship between Vo2max anddecremental index in low Vo2max group (r= 0.86, p= 0.001, no significant relationship medium Vo2max group (r= 0.14, p= 0.63 and negative significant relationship in high Vo2max group (r= - 0.64, p= 0.04. There are no significant relationship between Lactate accumulation and decremental index in medium (r= 0.005, p= 0.98 and high Vo2max groups (r=0.27, p= 0.45. Discussion: It is possible that the recovery of inter muscular resources relates to aerobic ability, but there are other factors effective in RSA rather than Vo2max and Lactate accumulation. The current study showed a normal curved relationship between Vo2max and RSA.

Mini MAX - Medicaid Sample

Data.gov (United States)

U.S. Department of Health & Human Services — To facilitate wider use of MAX, CMS contracted with Mathematica to convene a technical expert panel (TEP) and determine the feasibility of creating a sample file for...

Spindle epithelial tumor with thymus-like differentiation of thyroid gland: Report of two cases with follow-up

Directory of Open Access Journals (Sweden)

Nisa Azizun

2010-10-01

Full Text Available Spindle epithelial tumor with thymus-like differentiation (SETTLE is a rare malignant thyroid tumor showing thymic or related branchial pouch differentiation. The tumors are composed predominantly of spindle cells along with focal epithelial component and ductular formations. SETTLE occurs in young patients, with indolent growth and a tendency to develop delayed blood-borne metastases. We herein report two cases of SETTLE with a follow-up period of 64 months and 30 months, respectively.

Ketamine increases the frequency of electroencephalographic bicoherence peak on the alpha spindle area induced with propofol.

Science.gov (United States)

Hayashi, K; Tsuda, N; Sawa, T; Hagihira, S

2007-09-01

The reticular and thalamocortical system is known to play a prominent role in spindle wave activity, and the spindle wave is related to the sedative effects of anaesthetics. Recently, bispectral analysis of the EEG has been developed as a better method to indicate nonlinear regulation including the thalamocortical system linking to the cortical area. In the present study, in order to explore the interference of ketamine with the nonlinear regulation of the sub-cortical system, we examined the effect of ketamine on spindle alpha waves through the bispectral analysis. The study included 21 patients. Anaesthesia was induced and maintained using a propofol-TCI system (target-controlled infusion, with target concentration 3.5 microg ml(-1)). An A-2000 BIS monitor was used and the raw EEG signals were collected via an RS232 interface on a personal computer. Bicoherence, the normalized bispectrum, and power spectrum were analysed before and after i.v. administration of 1 mg kg(-1) racemic ketamine. Propofol caused alpha peaks in both power and bicoherence spectra, with average frequencies of 10.6 (SD 0.9) Hz and 10.7 (1.0) Hz, respectively. The addition of ketamine significantly shifted each peak to frequencies of 14.4 (1.4) Hz and 13.6 (1.5) Hz, respectively [P < 0.05, mean (SD)]. Ketamine shifted the alpha peaks of bicoherence induced by propofol to higher frequencies. This suggests that ketamine changes the alpha spindle rhythms through the modulation of the nonlinear sub-cortical reverberating network.

Phospho-Bcl-xL(Ser62) influences spindle assembly and chromosome segregation during mitosis.

Science.gov (United States)

Wang, Jianfang; Beauchemin, Myriam; Bertrand, Richard

2014-01-01

Functional analysis of a series of phosphorylation mutants reveals that Bcl-xL(Ser62Ala) influences cell entry into anaphase and mitotic exit in taxol-exposed cells compared with cells expressing wild-type Bcl-xL or a series of other phosphorylation mutants, an effect that appears to be independent of its anti-apoptotic activity. During normal mitosis progression, Bcl-xL(Ser62) is strongly phosphorylated by PLK1 and MAPK14/SAPKp38α at the prometaphase, metaphase, and the anaphase boundaries, while it is de-phosphorylated at telophase and cytokinesis. Phospho-Bcl-xL(Ser62) localizes in centrosomes with γ-tubulin and in the mitotic cytosol with some spindle-assembly checkpoint signaling components, including PLK1, BubR1, and Mad2. In taxol- and nocodazole-exposed cells, phospho-Bcl-xL(Ser62) also binds to Cdc20- Mad2-, BubR1-, and Bub3-bound complexes, while Bcl-xL(Ser62Ala) does not. Silencing Bcl-xL expression and expressing the phosphorylation mutant Bcl-xL(Ser62Ala) lead to an increased number of cells harboring mitotic spindle defects including multipolar spindle, chromosome lagging and bridging, aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h. Together, the data indicate that during mitosis, Bcl-xL(Ser62) phosphorylation impacts on spindle assembly and chromosome segregation, influencing chromosome stability. Observations of mitotic cells harboring aneuploidy with micro-, bi-, or multi-nucleated cells, and cells that fail to resolve undergo mitosis within 6 h were also made with cells expressing the phosphorylation mutant Bcl-xL(Ser49Ala) and dual mutant Bcl-xL(Ser49/62Ala).

Expanding the histologic spectrum of mucinous tubular and spindle cell carcinoma of the kidney.

Science.gov (United States)

Fine, Samson W; Argani, Pedram; DeMarzo, Angelo M; Delahunt, Brett; Sebo, Thomas J; Reuter, Victor E; Epstein, Jonathan I

2006-12-01

Mucinous tubular and spindle cell carcinomas (MTSCs) are polymorphic neoplasms characterized by small, elongated tubules lined by cuboidal cells and/or cords of spindled cells separated by pale mucinous stroma. Nonclassic morphologic variants and features of MTSC have not been well studied. We identified 17 previously unreported MTSCs from Surgical Pathology and consultative files of the authors and their respective institutions and studied their morphologic features. A total of 10/17 cases were considered "classic," as described above, with 5/10 showing at least focal (20% to 50%) tubular predominance without apparent mucinous matrix. Alcian blue staining revealed abundant (>50%) mucin in all classic cases. Seven of 17 MTSCs were classified as "mucin-poor," with little to no extracellular mucin appreciable by hematoxylin and eosin. Four of these cases showed equal tubular and spindled morphology, 2 cases showed spindle cell predominance (70%; 95%), and 1 case showed tubular predominance (90%). In 5/7 mucin-poor cases, staining for Alcian blue revealed scant (<10%) mucin in cellular areas with the other 2 cases having 30% mucin. Unusual histologic features identified in the 17 cases were: foamy macrophages (n=8), papillations/well formed papillae (n=6/n=1), focal clear cells in tubules (n=3), necrosis (n=3), oncocytic tubules (n=2; 40%, 5%), numerous small vacuoles (n=2), heterotopic bone (n=1), psammomatous calcification (n=1), and nodular growth with lymphocytic cuffing (n=1). An exceptional case contained a well-circumscribed, HMB45-positive angiomyolipoma within the MTSC. MTSCs may be "mucin-poor" and show a marked predominance of either of its principal morphologic components, which coupled with the presence of other unusual features such as clear cells, papillations, foamy macrophages, and necrosis, may mimic other forms of renal cell carcinoma. Pathologists must be aware of the spectrum of histologic findings within MTSCs to ensure their accurate diagnosis.

Validation of a ramp running protocol for determination of the true VO2max in mice

Directory of Open Access Journals (Sweden)

Mohamed Ayachi

2016-08-01

Full Text Available In the field of comparative physiology, it remains to be established whether the concept of VO2max is valid in the mouse and, if so, how this value can be accurately determined. In humans, VO2max is generally considered to correspond to the plateau observed when VO2 no longer rises with an increase in workload. In contrast, the concept of VO2peak tends to be used in murine studies. The objectives of the present study were to determine whether (i a continuous ramp protocol yielded a higher VO2peak than a stepwise, incremental protocol, and (ii the VO2peak measured in the ramp protocol corresponded to VO2max. The three protocols (based on intensity-controlled treadmill running until exhaustion with eight female FVB/N mice were performed in random order: (a an incremental protocol that begins at 10 m.min-1 speed and increases by 3 m.min-1 every 3 min. (b a ramp protocol with slow acceleration (3 m.min-2, and (c a ramp protocol with fast acceleration (12 m.min-2. Each protocol was performed with two slopes (0° and 25°. Hence, each mouse performed six exercise tests. We found that the value of VO2peak was protocol-dependent (p 8 mmol.l-1 and a respiratory exchange ratio >1. The total duration of the 3 m.min-2 0° ramp protocol was shorter than that of the incremental protocol. Taken as a whole, our results suggest that VO2max in the mouse is best determined by applying a ramp exercise protocol with slow acceleration and no treadmill slope.

Complete low-frequency bandgap in a two-dimensional phononic crystal with spindle-shaped inclusions

Science.gov (United States)

Ting, Wang; Hui, Wang; Mei-Ping, Sheng; Qing-Hua, Qin

2016-04-01

A two-dimensional phononic crystal (PC) structure possessing a relatively low frequency range of complete bandgap is presented. The structure is composed of periodic spindle-shaped plumbum inclusions in a rubber matrix which forms a square lattice. The dispersion relation, transmission spectrum and displacement field are studied using the finite element method in conjunction with the Bloch theorem. Numerical results show that the present PC structure can achieve a large complete bandgap in a relatively low frequency range compared with two inclusions of different materials, which is useful in low-frequency noise and vibration control and can be designed as a low frequency acoustic filter and waveguides. Moreover, the transmission spectrum and effective mass are evaluated to validate the obtained band structure. It is interesting to see that within the band gap the effective mass becomes negative, resulting in an imaginary wave speed and wave exponential attenuation. Finally, sensitivity analysis of the effect of geometrical parameters of the presented PC structure on the lowest bandgap is performed to investigate the variations of the bandgap width and frequency. Project supported by the China Scholarship Council.

Topological defects in confined populations of spindle-shaped cells

Science.gov (United States)

Duclos, Guillaume; Erlenkämper, Christoph; Joanny, Jean-François; Silberzan, Pascal

2017-01-01

Most spindle-shaped cells (including smooth muscles and sarcomas) organize in vivo into well-aligned `nematic’ domains, creating intrinsic topological defects that may be used to probe the behaviour of these active nematic systems. Active non-cellular nematics have been shown to be dominated by activity, yielding complex chaotic flows. However, the regime in which live spindle-shaped cells operate, and the importance of cell-substrate friction in particular, remains largely unexplored. Using in vitro experiments, we show that these active cellular nematics operate in a regime in which activity is effectively damped by friction, and that the interaction between defects is controlled by the system’s elastic nematic energy. Due to the activity of the cells, these defects behave as self-propelled particles and pairwise annihilate until all displacements freeze as cell crowding increases. When confined in mesoscopic circular domains, the system evolves towards two identical +1/2 disclinations facing each other. The most likely reduced positions of these defects are independent of the size of the disk, the cells’ activity or even the cell type, but are well described by equilibrium liquid crystal theory. These cell-based systems thus operate in a regime more stable than other active nematics, which may be necessary for their biological function.

Vibration of rotating-shaft design spindles with flexible bases

Science.gov (United States)

Tseng, Chaw-Wu

The purpose of this study is to demonstrate an accurate mathematical model predicting forced vibration of rotating-shaft HDD spindle motors with flexible stationary parts. The mathematical model consists of three parts: a rotating part, a stationary part, and bearings. The rotating part includes a flexible hub, a flexible shaft press-fit into the hub, and N elastic disks mounted on the hub. The stationary part can include motor bracket (stator), base casting, and top cover. The bearings under consideration can be ball bearings or hydrodynamic bearings (HDB). The rotating disks are modelled through the classical plate theory. The rotating part (except the disks) and the stationary part are modelled through finite element analyses (FEA). With mode shapes and natural frequencies obtained from FEA, the kinetic and potential energies of the rotating and stationary parts are formulated and discretized to compensate for the gyroscopic effects from rotation. Finally, use of Lagrange equation results in the equations of motion. To verify the mathematical model, frequency response functions are measured experimentally for an HDB spindle carrying two identical disks at motor and drive levels. Experimental measurements agree very well with theoretical predictions not only in resonance frequency but also in resonance amplitude.

Spindle vibration and sound field measurement using optical vibrometry

OpenAIRE

Tatar, Kourosh

2008-01-01

Mechanical systems often produce a considerable amount of vibration and noise. To be able to obtain a complete picture of the dynamic behaviour of these systems, vibration and sound measurements are of significant importance. Optical metrology is well-suited for non-intrusive measurements on complex objects. The development and the use of remote non-contact vibration measurement methods for spindles are described and vibration measurements on thin- walled structures and sound field measuremen...

Max Jakobsoni saatuseaastad, soomlased ja meie / Imbi Paju

Index Scriptorium Estoniae

Paju, Imbi, 1959-

2008-01-01

Soome politoloogist ja diplomaadist Max Jakobsonist ja tema uuest raamatust "Saatuseaastad. Soome tõusis, andis Venemaale järele ja pääses". Artiklis on juttu ka Max Jakobsoni suhetest Eesti presidentide Lennart Meri ja Toomas Hendrik Ilvesega

Effect of speed endurance and strength training on performance, running economy and muscular adaptations in endurance-trained runners

DEFF Research Database (Denmark)

Vorup Petersen, Jacob; Tybirk, Jonas; Gunnarsson, Thomas Petursson

2016-01-01

PURPOSE: To investigate the effects of combined strength and speed endurance (SE) training along with a reduced training volume on performance, running economy and muscular adaptations in endurance-trained runners. METHODS: Sixteen male endurance runners (VO2-max: ~60 ml kg(-1) min(-1)) were rand...... and speed endurance training, along with a reduced training volume, can improve short-term exercise capacity and induce muscular adaptations related to anaerobic capacity in endurance-trained runners.......PURPOSE: To investigate the effects of combined strength and speed endurance (SE) training along with a reduced training volume on performance, running economy and muscular adaptations in endurance-trained runners. METHODS: Sixteen male endurance runners (VO2-max: ~60 ml kg(-1) min(-1)) were...... randomly assigned to either a combined strength and SE training (CSS; n = 9) or a control (CON; n = 7) group. For 8 weeks, CSS replaced their normal moderate-intensity training (~63 km week(-1)) with SE (2 × week(-1)) and strength training (2 × week(-1)) as well as aerobic high (1 × week(-1)) and moderate...

MLL/WDR5 Complex Regulates Kif2A Localization to Ensure Chromosome Congression and Proper Spindle Assembly during Mitosis.

Science.gov (United States)

Ali, Aamir; Veeranki, Sailaja Naga; Chinchole, Akash; Tyagi, Shweta

2017-06-19

Mixed-lineage leukemia (MLL), along with multisubunit (WDR5, RbBP5, ASH2L, and DPY30) complex catalyzes the trimethylation of H3K4, leading to gene activation. Here, we characterize a chromatin-independent role for MLL during mitosis. MLL and WDR5 localize to the mitotic spindle apparatus, and loss of function of MLL complex by RNAi results in defects in chromosome congression and compromised spindle formation. We report interaction of MLL complex with several kinesin and dynein motors. We further show that the MLL complex associates with Kif2A, a member of the Kinesin-13 family of microtubule depolymerase, and regulates the spindle localization of Kif2A during mitosis. We have identified a conserved WDR5 interaction (Win) motif, so far unique to the MLL family, in Kif2A. The Win motif of Kif2A engages in direct interactions with WDR5 for its spindle localization. Our findings highlight a non-canonical mitotic function of MLL complex, which may have a direct impact on chromosomal stability, frequently compromised in cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

Method for Vibration Response Simulation and Sensor Placement Optimization of a Machine Tool Spindle System with a Bearing Defect

Science.gov (United States)

Cao, Hongrui; Niu, Linkai; He, Zhengjia

2012-01-01

Bearing defects are one of the most important mechanical sources for vibration and noise generation in machine tool spindles. In this study, an integrated finite element (FE) model is proposed to predict the vibration responses of a spindle bearing system with localized bearing defects and then the sensor placement for better detection of bearing faults is optimized. A nonlinear bearing model is developed based on Jones' bearing theory, while the drawbar, shaft and housing are modeled as Timoshenko's beam. The bearing model is then integrated into the FE model of drawbar/shaft/housing by assembling equations of motion. The Newmark time integration method is used to solve the vibration responses numerically. The FE model of the spindle-bearing system was verified by conducting dynamic tests. Then, the localized bearing defects were modeled and vibration responses generated by the outer ring defect were simulated as an illustration. The optimization scheme of the sensor placement was carried out on the test spindle. The results proved that, the optimal sensor placement depends on the vibration modes under different boundary conditions and the transfer path between the excitation and the response. PMID:23012514

Max-Plus Stochastic Control and Risk-Sensitivity

International Nuclear Information System (INIS)

Fleming, Wendell H.; Kaise, Hidehiro; Sheu, Shuenn-Jyi

2010-01-01

In the Maslov idempotent probability calculus, expectations of random variables are defined so as to be linear with respect to max-plus addition and scalar multiplication. This paper considers control problems in which the objective is to minimize the max-plus expectation of some max-plus additive running cost. Such problems arise naturally as limits of some types of risk sensitive stochastic control problems. The value function is a viscosity solution to a quasivariational inequality (QVI) of dynamic programming. Equivalence of this QVI to a nonlinear parabolic PDE with discontinuous Hamiltonian is used to prove a comparison theorem for viscosity sub- and super-solutions. An example from mathematical finance is given, and an application in nonlinear H-infinity control is sketched.

Digital logic circuit design with ALTERA MAX+PLUS II

International Nuclear Information System (INIS)

Lee, Seung Ho; Park, Yong Su; Park, Gun Jong; Lee, Ju Heon

2006-09-01

This book is composed of five parts. The first part has introduction of ALTERA MAX+PLUS II and graphic editor, text editor, compiler, waveform editor simulator and timing analyzer of it. The second part is about direction of digital logic circuit design with training kit. The third part has grammar and practice of VHDL in ALTERA MAX+PLUS II including example and history of VHDL. The fourth part shows the design example of digital logic circuit by VHDL of ALTERA MAX+PLUS II which lists designs of adder and subtractor, code converter, counter, state machine and LCD module. The last part explains design example of digital logic circuit by graphic editor in ALTERA MAX+PLUS II.

Max Weber Visits America: A Review of the Video

Directory of Open Access Journals (Sweden)

Michael Wise

2006-11-01

Full Text Available The North Carolina Sociological Society is proud to announce the long-awaited video of Max Weber's trip to North Carolina as retold by two of his cousins. Max Weber made a trip to visit relatives in Mount Airy, North Carolina, in 1904. This 2004 narrative by Larry Keeter and Stephen Hall is the story of locating and interviewing two living eyewitnesses (1976 to Max Weber's trip. The video includes information about Weber's contributions to modern sociology. Dowloadable files are provided using the .mp4 format. The video should appeal to students and professors interested in Max Weber. It can be included in courses ranging from introductory sociology to theory.

Muscle spindles in elongation of the extremity: proprioceptive conflict or activity deficit?

Science.gov (United States)

Shevtsov, V I; Saifutdinov, M S; Chikorina, N K

2008-07-01

Comparison of electrophysiological and morphological parameters of shin muscles of experimental animals during shin elongation by Ilizarov's method indicates involvement of muscle spindles into reconstruction of the skeletal muscular tissue in response to its dosed distraction, which results in temporary deficit of specific somatosensory afferentation.

Sleep spindle density in narcolepsy

DEFF Research Database (Denmark)

Christensen, Julie Anja Engelhard; Nikolic, Miki; Hvidtfelt, Mathias

2017-01-01

BACKGROUND: Patients with narcolepsy type 1 (NT1) show alterations in sleep stage transitions, rapid-eye-movement (REM) and non-REM sleep due to the loss of hypocretinergic signaling. However, the sleep microstructure has not yet been evaluated in these patients. We aimed to evaluate whether...... the sleep spindle (SS) density is altered in patients with NT1 compared to controls and patients with narcolepsy type 2 (NT2). METHODS: All-night polysomnographic recordings from 28 NT1 patients, 19 NT2 patients, 20 controls (C) with narcolepsy-like symptoms, but with normal cerebrospinal fluid hypocretin...... levels and multiple sleep latency tests, and 18 healthy controls (HC) were included. Unspecified, slow, and fast SS were automatically detected, and SS densities were defined as number per minute and were computed across sleep stages and sleep cycles. The between-cycle trends of SS densities in N2...

The interactional foundations of MaxEnt: Open questions

Energy Technology Data Exchange (ETDEWEB)

Harré, Michael S., E-mail: michael.harre@sydney.edu.au [Complex Systems Research Group, School of Civil Engineering, The University of Sydney, Sydney NSW 2006 (Australia)

2014-12-05

One of the simplest and potentially most useful techniques to be developed in the 20{sup th} century, a century noted for an ever more mathematically sophisticated formulation of the sciences, is that of maximising the entropy of a system in order to generate a descriptive, stochastic model of that system in closed form, often abbreviated to MaxEnt. The extension of MaxEnt to systems beyond the physics from which it originated is hampered by the fact that the microscopic physical interactions that are not justified or justifiable within the MaxEnt framework need to be falsifiably evaluated in each new field of application. It is not obvious that such justification exists for many systems in which the interactions are not directly based on physics. For example what is the justification for the use of MaxEnt in biology, climate modelling or economics? Is it simply a useful heuristic or is there some deeper connection with the foundations of some systems? Without further critical examination of the microscopic foundations that give rise to the success of the MaxEnt principle it is difficult to motivate the use of such techniques in other fields except through theoretically an practically unsatisfying analogical arguments. This article briefly presents the basis of MaxEnt principles as originally introduced in statistical mechanics in the Jaynes form, the Tsallis form and the Rényi form. Several different applications are introduced including that of ecological diversity where maximising the different diversity measures is equivalent to maximising different entropic functionals.

The interactional foundations of MaxEnt: Open questions

International Nuclear Information System (INIS)

Harré, Michael S.

2014-01-01

One of the simplest and potentially most useful techniques to be developed in the 20 th century, a century noted for an ever more mathematically sophisticated formulation of the sciences, is that of maximising the entropy of a system in order to generate a descriptive, stochastic model of that system in closed form, often abbreviated to MaxEnt. The extension of MaxEnt to systems beyond the physics from which it originated is hampered by the fact that the microscopic physical interactions that are not justified or justifiable within the MaxEnt framework need to be falsifiably evaluated in each new field of application. It is not obvious that such justification exists for many systems in which the interactions are not directly based on physics. For example what is the justification for the use of MaxEnt in biology, climate modelling or economics? Is it simply a useful heuristic or is there some deeper connection with the foundations of some systems? Without further critical examination of the microscopic foundations that give rise to the success of the MaxEnt principle it is difficult to motivate the use of such techniques in other fields except through theoretically an practically unsatisfying analogical arguments. This article briefly presents the basis of MaxEnt principles as originally introduced in statistical mechanics in the Jaynes form, the Tsallis form and the Rényi form. Several different applications are introduced including that of ecological diversity where maximising the different diversity measures is equivalent to maximising different entropic functionals

Free Vibration Analysis of a Spinning Flexible DISK-SPINDLE System Supported by Ball Bearing and Flexible Shaft Using the Finite Element Method and Substructure Synthesis

Science.gov (United States)

JANG, G. H.; LEE, S. H.; JUNG, M. S.

2002-03-01

Free vibration of a spinning flexible disk-spindle system supported by ball bearing and flexible shaft is analyzed by using Hamilton's principle, FEM and substructure synthesis. The spinning disk is described by using the Kirchhoff plate theory and von Karman non-linear strain. The rotating spindle and stationary shaft are modelled by Rayleigh beam and Euler beam respectively. Using Hamilton's principle and including the rigid body translation and tilting motion, partial differential equations of motion of the spinning flexible disk and spindle are derived consistently to satisfy the geometric compatibility in the internal boundary between substructures. FEM is used to discretize the derived governing equations, and substructure synthesis is introduced to assemble each component of the disk-spindle-bearing-shaft system. The developed method is applied to the spindle system of a computer hard disk drive with three disks, and modal testing is performed to verify the simulation results. The simulation result agrees very well with the experimental one. This research investigates critical design parameters in an HDD spindle system, i.e., the non-linearity of a spinning disk and the flexibility and boundary condition of a stationary shaft, to predict the free vibration characteristics accurately. The proposed method may be effectively applied to predict the vibration characteristics of a spinning flexible disk-spindle system supported by ball bearing and flexible shaft in the various forms of computer storage device, i.e., FDD, CD, HDD and DVD.

analysis of gear milling at vari gear milling at various gear milling

African Journals Online (AJOL)

eobe

2 DEPARTMENT OF INDUSTRIAL AND ... conventional machine tools, cutter tool wear, .... speed, and tool wear on case-hardened gear is also .... study. The gear cutter is mounted on the spindle. Spindle speeds and feed rates are essential ...

Piezoelectric self-sensing actuator for active vibration control of motorized spindle based on adaptive signal separation

Science.gov (United States)

He, Ye; Chen, Xiaoan; Liu, Zhi; Qin, Yi

2018-06-01

The motorized spindle is the core component of CNC machine tools, and the vibration of it reduces the machining precision and service life of the machine tools. Owing to the fast response, large output force, and displacement of the piezoelectric stack, it is often used as the actuator in the active vibration control of the spindle. A piezoelectric self-sensing actuator (SSA) can reduce the cost of the active vibration control system and simplify the structure by eliminating the use of a sensor, because a SSA can have both actuating and sensing functions at the same time. The signal separation method of a SSA based on a bridge circuit is widely applied because of its simple principle and easy implementation. However, it is difficult to maintain dynamic balance of the circuit. Prior research has used adaptive algorithm to balance of the bridge circuit on the flexible beam dynamically, but those algorithms need no correlation between sensing and control voltage, which limit the applications of SSA in the vibration control of the rotor-bearing system. Here, the electromechanical coupling model of the piezoelectric stack is established, followed by establishment of the dynamic model of the spindle system. Next, a new adaptive signal separation method based on the bridge circuit is proposed, which can separate relative small sensing voltage from related mixed voltage adaptively. The experimental results show that when the self-sensing signal obtained from the proposed method is used as a displacement signal, the vibration of the motorized spindle can be suppressed effectively through a linear quadratic Gaussian (LQG) algorithm.

Slow Freezing or Vitrification of Oocytes: Their Effects on Survival and Meiotic Spindles, and the Time Schedule for Clinical Practice

Directory of Open Access Journals (Sweden)

Shee-Uan Chen

2009-03-01

Full Text Available Both the slow-freezing method with increased sucrose concentration and new vitrification techniques significantly improve the results of cryopreservation of human oocytes. The recent perfection for vitrification includes the concepts of increase of cooling and warming rates using minimum volume methods, and decrease of toxicity by reducing the concentration of cryoprotectants. In the recent literature, the survival of cryopreserved oocytes ranged from 74% to 90% using the slow-freezing method and from 84% to 99% by vitrification. Overall, the survival rate of oocytes from vitrification (95%, 899/948 appeared higher than that of the slow-freezing method (75%, 1,275/1,683. The microtubules of meiotic spindles are vulnerable to the thermal changes and will depolymerize. After incubation, the microtubules repolymerize. Spindle recovery is faster after vitrification than slow freezing. Even so, after 3 hours of incubation, spindle recuperation is similar between vitrification and slow freezing. Considering both aspects of spindle recovery and oocyte aging, the time schedule for oocyte cryopreservation program makes fertilization in the optimal time. Intracytoplasmic sperm injection is performed for oocytes at 3 hours of post-thaw incubation from the slow-freezing method and 2 hours from vitrification, with restoration of meiotic spindles. The pregnancy potential of cryopreserved oocytes is comparable to that of fresh oocytes or frozen embryos. Cryopreservation of oocytes would importantly contribute to oocyte donation and preservation of fertility for cancer patients.

Relations between ultrastructure of mitotic spindle and chromosome translocation

OpenAIRE

Jadwiga A. Tarkowska

2014-01-01

Dividing endosperm cells of Haemanthus katherinae Bak. treated with an 0.25 per cent mixture of water-soluble glycosides from Nerium oleander were insepected in a light microscope (LM) and severe disturbances were found in all phases of mitosis. The same cells were observed in the electron microscope (EM) and relations were noted and analysed between the chromosome arrangement and the submicroscopic structure of the mitotuc spindle. The successive steps in the disintegration of the formed spi...

Plane of vertebral movement eliciting muscle lengthening history in the low back influences the decrease in muscle spindle responsiveness of the cat.

Science.gov (United States)

Ge, Weiqing; Cao, Dong-Yuan; Long, Cynthia R; Pickar, Joel G

2011-12-01

Proprioceptive feedback is thought to play a significant role in controlling both lumbopelvic and intervertebral orientations. In the lumbar spine, a vertebra's positional history along the dorsal-ventral axis has been shown to alter the position, movement, and velocity sensitivity of muscle spindles in the multifidus and longissimus muscles. These effects appear due to muscle history. Because spinal motion segments have up to 6 degrees of freedom for movement, we were interested in whether the axis along which the history is applied differentially affects paraspinal muscle spindles. We tested the null hypothesis that the loading axis, which creates a vertebra's positional history, has no effect on a lumbar muscle spindle's subsequent response to vertebral position or movement. Identical displacements were applied along three orthogonal axes directly at the L(6) spinous process using a feedback motor system under displacement control. Single-unit nerve activity was recorded from 60 muscle spindle afferents in teased filaments from L(6) dorsal rootlets innervating intact longissimus or multifidus muscles of deeply anesthetized cats. Muscle lengthening histories along the caudal-cranial and dorsal-ventral axis, compared with the left-right axis, produced significantly greater reductions in spindle responses to vertebral position and movement. The spinal anatomy suggested that the effect of a lengthening history is greatest when that history had occurred along an axis lying within the anatomical plane of the facet joint. Speculation is made that the interaction between normal spinal mechanics and the inherent thixotropic property of muscle spindles poses a challenge for feedback and feedforward motor control of the lumbar spine.

Surface morphology study in high speed milling of soda lime glass

Science.gov (United States)

Konneh, Mohamed; Bagum, Mst. Nasima; Ali, Mohammad Yeakub; Amin, A. K. M. Nurul

2018-05-01

Soda lime glass has a wide range of applications in optical, bio-medical and semi-conductor industries. It is undeniably a challenging task to produce micro finish surface on an amorphous brittle solid like soda lime glass due to its low fracture toughness. In order to obtain such a finish surface, ductile machining has been exploited, as this usually cause's plastic flow which control crack propagation. At sub-micro scale cutting parameters, researchers achieved nano finish surface in micro milling operation using coated tool. However it is possible to enhance the rate of material removal (RMR) of soda lime glass at flexible cutting condition. High speed cutting at micro meter level, extend of thermal softening might be prominent than the strain gradient strengthening. The purpose of this study was to explore the effects of high cutting speed end milling parameters on the surface texture of soda lime glass using uncoated carbide tool. The spindle speed, depth of cut and feed rate were varied from 20,000 to 40,000 rpm, 10 to 30 mm/min and 30 to 50 µm respectively. Mathematical model of roughness has been developed using Response Surface Methodology (RSM). Experimental verification confirmed that surface roughness (Ra) 0.38 µm is possible to achieve at increased RMR, 4.71 mm3/min.

De Max-Planck medaille

NARCIS (Netherlands)

Heijmans, H.G.; van Woerkom, P.Th.L.M.; Ankersmit, W.; Hagman, R.; Heijmans, H.G.; Olsder, G.J.; van de Schootbrugge, G.

2017-01-01

De Max-Planck-Medaille is een onderscheiding die sinds 1929 jaarlijks wordt uitgereikt door de toentertijd grootste vereniging van natuurkundigen ter wereld: de Deutsche Physikalische Gesellschaft. Het is als het ware de Nobelprijs voor de theoretische natuurkunde, volgens de natuurkundigen zelf. In

Intertextuality and Television Discourse: The Max Headroom Story.

Science.gov (United States)

Braddlee

Max Headroom, the computer-generated media personality, presents a good opportunity for an investigation of the degree of intertextuality in television. Max combines narrative genres (science fiction and film noir), television program types (prime-time episodic narrative, made-for-TV movie, talkshows), advertising and programming, and electronic…

Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis

Directory of Open Access Journals (Sweden)

En-Ju Chou

2016-03-01

Full Text Available CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity.

p600 regulates spindle orientation in apical neural progenitors and contributes to neurogenesis in the developing neocortex

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Camille Belzil

2014-05-01

Full Text Available Apical neural progenitors (aNPs drive neurogenesis by means of a program consisting of self-proliferative and neurogenic divisions. The balance between these two manners of division sustains the pool of apical progenitors into late neurogenesis, thereby ensuring their availability to populate the brain with terminal cell types. Using knockout and in utero electroporation mouse models, we report a key role for the microtubule-associated protein 600 (p600 in the regulation of spindle orientation in aNPs, a cellular event that has been associated with cell fate and neurogenesis. We find that p600 interacts directly with the neurogenic protein Ndel1 and that aNPs knockout for p600, depleted of p600 by shRNA or expressing a Ndel1-binding p600 fragment all display randomized spindle orientation. Depletion of p600 by shRNA or expression of the Ndel1-binding p600 fragment also results in a decreased number of Pax6-positive aNPs and an increased number of Tbr2-positive basal progenitors destined to become neurons. These Pax6-positive aNPs display a tilted mitotic spindle. In mice wherein p600 is ablated in progenitors, the production of neurons is significantly impaired and this defect is associated with microcephaly. We propose a working model in which p600 controls spindle orientation in aNPs and discuss its implication for neurogenesis.

A gene encoding the major beta tubulin of the mitotic spindle in Physarum polycephalum plasmodia

Energy Technology Data Exchange (ETDEWEB)

Burland, T.G.; Paul, E.C.A.; Oetliker, M.; Dove, W.F.

1988-03-01

The multinucleate plasmodium of Physarum polycephalum is unusual among eucaryotic cells in that it uses tubulins only in mitotic-spindle microtubules; cytoskeletal, flagellar, and centriolar microtubules are absent in this cell type. The authors identified a ..beta..-tubulin cDNA clone, ..beta..105, which is shown to correspond to the transcript of the betC ..beta..-tubulin locus and to encode ..beta..2 tubulin, the ..beta.. tubulin expressed specifically in the plasmodium and used exclusively in the mitotic spindle. Physarum amoebae utilize tubulins in the cytoskeleton, centrioles, and flagella, in addition to the mitotic spindle. Sequence analysis shows that ..beta..2 tubulin is only 83% identical to the two ..beta.. tubulins expressed in amoebae. This compares with 70 to 83% identity between Physarum ..beta..2 tubulin and the ..beta.. tubulins of yeasts, fungi, alga, trypanosome, fruit fly, chicken, and mouse. On the other hand, Physarum ..beta..2 tubulin is no more similar to, for example, Aspergillus ..beta.. tubulins than it is to those of Drosophila melanogaster or mammals. Several eucaryotes express at least one widely diverged ..beta.. tubulin as well as one or more ..beta.. tubulins that conform more closely to a consensus ..beta..-tubulin sequence. The authors suggest that ..beta..-tubulins diverge more when their expression pattern is restricted, especially when this restriction results in their use in fewer functions. This divergence among ..beta.. tubulins could have resulted through neutral drift. For example, exclusive use of Physarum ..beta..2 tubulin in the spindle may have allowed more amino acid substitutions than would be functionally tolerable in the ..beta.. tubulins that are utilized in multiple microtubular organelles. Alternatively, restricted use of ..beta.. tubulins may allow positive selection to operate more freely to refine ..beta..-tubulin function.

FUSIMOTOR EFFECTS OF MIDBRAIN STIMULATION ON JAW MUSCLE-SPINDLES OF THE ANESTHETIZED CAT

NARCIS (Netherlands)

TAYLOR, A; JUCH, PJW

The effects of electrical stimulation within the midbrain on fusimotor output to the jaw elevator muscles were studied in anaesthetized cats. Muscle spindle afferents recorded in the mesencephalic trigeminal nucleus were categorised as primary or secondary by their responses to succinylcholine

Max Weber Visits America: A Review of the Video

OpenAIRE

Michael Wise

2006-01-01

The North Carolina Sociological Society is proud to announce the long-awaited video of Max Weber's trip to North Carolina as retold by two of his cousins. Max Weber made a trip to visit relatives in Mount Airy, North Carolina, in 1904. This 2004 narrative by Larry Keeter and Stephen Hall is the story of locating and interviewing two living eyewitnesses (1976) to Max Weber's trip. The video includes information about Weber's contributions to modern sociology. Dowloadable files are provided...

Investigation the gas film in micro scale induced error on the performance of the aerostatic spindle in ultra-precision machining

Science.gov (United States)

Chen, Dongju; Huo, Chen; Cui, Xianxian; Pan, Ri; Fan, Jinwei; An, Chenhui

2018-05-01

The objective of this work is to study the influence of error induced by gas film in micro-scale on the static and dynamic behavior of a shaft supported by the aerostatic bearings. The static and dynamic balance models of the aerostatic bearing are presented by the calculated stiffness and damping in micro scale. The static simulation shows that the deformation of aerostatic spindle system in micro scale is decreased. For the dynamic behavior, both the stiffness and damping in axial and radial directions are increased in micro scale. The experiments of the stiffness and rotation error of the spindle show that the deflection of the shaft resulting from the calculating parameters in the micro scale is very close to the deviation of the spindle system. The frequency information in transient analysis is similar to the actual test, and they are also higher than the results from the traditional case without considering micro factor. Therefore, it can be concluded that the value considering micro factor is closer to the actual work case of the aerostatic spindle system. These can provide theoretical basis for the design and machining process of machine tools.

Proprioceptive Feedback through a Neuromorphic Muscle Spindle Model

Directory of Open Access Journals (Sweden)

Lorenzo Vannucci

2017-06-01

Full Text Available Connecting biologically inspired neural simulations to physical or simulated embodiments can be useful both in robotics, for the development of a new kind of bio-inspired controllers, and in neuroscience, to test detailed brain models in complete action-perception loops. The aim of this work is to develop a fully spike-based, biologically inspired mechanism for the translation of proprioceptive feedback. The translation is achieved by implementing a computational model of neural activity of type Ia and type II afferent fibers of muscle spindles, the primary source of proprioceptive information, which, in mammals is regulated through fusimotor activation and provides necessary adjustments during voluntary muscle contractions. As such, both static and dynamic γ-motoneurons activities are taken into account in the proposed model. Information from the actual proprioceptive sensors (i.e., motor encoders is then used to simulate the spindle contraction and relaxation, and therefore drive the neural activity. To assess the feasibility of this approach, the model is implemented on the NEST spiking neural network simulator and on the SpiNNaker neuromorphic hardware platform and tested on simulated and physical robotic platforms. The results demonstrate that the model can be used in both simulated and real-time robotic applications to translate encoder values into a biologically plausible neural activity. Thus, this model provides a completely spike-based building block, suitable for neuromorphic platforms, that will enable the development of sensory-motor closed loops which could include neural simulations of areas of the central nervous system or of low-level reflexes.

Sleep spindle-related reactivation of category-specific cortical regions after learning face-scene associations

DEFF Research Database (Denmark)

Bergmann, Til O; Mölle, Matthias; Diedrichs, Jens

2012-01-01

Newly acquired declarative memory traces are believed to be reactivated during NonREM sleep to promote their hippocampo-neocortical transfer for long-term storage. Yet it remains a major challenge to unravel the underlying neuronal mechanisms. Using simultaneous electroencephalography (EEG......-coupled reactivation of brain regions representing the specific task stimuli was traced during subsequent NonREM sleep with EEG-informed fMRI. Relative to the control task, learning face-scene associations triggered a stronger combined activation of neocortical and hippocampal regions during subsequent sleep. Notably......) and functional magnetic resonance imaging (fMRI) recordings in humans, we show that sleep spindles play a key role in the reactivation of memory-related neocortical representations. On separate days, participants either learned face-scene associations or performed a visuomotor control task. Spindle...

An examination of training on the VertiMax resisted jumping device for improvements in lower body power in highly trained college athletes .

Science.gov (United States)

Rhea, Matthew R; Peterson, Mark D; Oliverson, Jeff R; Ayllón, Fernando Naclerio; Potenziano, Ben J

2008-05-01

Training to develop superior muscular power has become a key component to most progressive sport conditioning programs. Conventional resistance training, plyometrics, and speed/agility modalities have all been employed in an effort to realize superlative combinations of training stimuli. New training devices such as the VertiMax resisted jump trainer are marketed as a means of improving lower body reactive power. The purpose of this study was to evaluate the effectiveness of the VertiMax, in combination with traditional training modalities, for improvements in lower body power among highly trained athletes. Forty men and women Division I collegiate athletes representing the sports of baseball, basketball, soccer, gymnastics, and track completed a 12-week mixed-methods training program. Two groups were constructed with both groups performing the same conventional resistance training and strength training exercises. The training control group performed traditional plyometric exercises while the experimental group performed similar loaded jump training on the VertiMax. Lower body power was measured before and after the training program by the TENDO FiTROdyne Powerlizer and statistically compared for differences between groups. Data analyses identified a significant (p training alone (effect size = 0.09). These data convincingly demonstrate that the VertiMax represents an effective strategy for developing lower body power among trained college athletes, when combined with traditional strength and conditioning approaches.

Autodesk 3ds Max 2013 essentials

CERN Document Server

Derakhshani, Dariush

2012-01-01

A four-color, task-based Autodesk Official Training Guide covering the core features of 3ds Max Beginning users of this popular 3D animation and effects software will find everything they need for a thorough understanding of the software's key features and functions in this colorful guide. The authors break down the complexities of learning 3D software and get you going right away with interesting, job-related projects. You'll learn the basics of modeling, texturing, animating, lighting, visualization, and visual effects with 3ds Max, exploring the methods and why they are used as they are.

Autodesk 3ds Max 2014 bible

CERN Document Server

Murdock, Kelly L

2013-01-01

A complete reference covering the newest version of 3ds Max software Autodesk 3ds Max is the popular 3D modeling, animation, rendering, and compositing software preferred by game developers and graphic designers in film and television. This comprehensive reference not only introduces beginners to this pricey and complex software, but also serves as a reference for experienced users. Packed with expert advice from popular author Kelly Murdock, it begins with a Quick Start tutorial to get you up and running, then continues with more than 150 step-by-step tutorials, advanced coverage, and plenty

A Role for the Chaperone Complex BAG3-HSPB8 in Actin Dynamics, Spindle Orientation and Proper Chromosome Segregation during Mitosis.

Science.gov (United States)

Fuchs, Margit; Luthold, Carole; Guilbert, Solenn M; Varlet, Alice Anaïs; Lambert, Herman; Jetté, Alexandra; Elowe, Sabine; Landry, Jacques; Lavoie, Josée N

2015-10-01

The co-chaperone BAG3, in complex with the heat shock protein HSPB8, plays a role in protein quality control during mechanical strain. It is part of a multichaperone complex that senses damaged cytoskeletal proteins and orchestrates their seclusion and/or degradation by selective autophagy. Here we describe a novel role for the BAG3-HSPB8 complex in mitosis, a process involving profound changes in cell tension homeostasis. BAG3 is hyperphosphorylated at mitotic entry and localizes to centrosomal regions. BAG3 regulates, in an HSPB8-dependent manner, the timely congression of chromosomes to the metaphase plate by influencing the three-dimensional positioning of the mitotic spindle. Depletion of BAG3 caused defects in cell rounding at metaphase and dramatic blebbing of the cortex associated with abnormal spindle rotations. Similar defects were observed upon silencing of the autophagic receptor p62/SQSTM1 that contributes to BAG3-mediated selective autophagy pathway. Mitotic cells depleted of BAG3, HSPB8 or p62/SQSTM1 exhibited disorganized actin-rich retraction fibres, which are proposed to guide spindle orientation. Proper spindle positioning was rescued in BAG3-depleted cells upon addition of the lectin concanavalin A, which restores cortex rigidity. Together, our findings suggest the existence of a so-far unrecognized quality control mechanism involving BAG3, HSPB8 and p62/SQSTM1 for accurate remodelling of actin-based mitotic structures that guide spindle orientation.

A Role for the Chaperone Complex BAG3-HSPB8 in Actin Dynamics, Spindle Orientation and Proper Chromosome Segregation during Mitosis.

Directory of Open Access Journals (Sweden)

Margit Fuchs

2015-10-01

Full Text Available The co-chaperone BAG3, in complex with the heat shock protein HSPB8, plays a role in protein quality control during mechanical strain. It is part of a multichaperone complex that senses damaged cytoskeletal proteins and orchestrates their seclusion and/or degradation by selective autophagy. Here we describe a novel role for the BAG3-HSPB8 complex in mitosis, a process involving profound changes in cell tension homeostasis. BAG3 is hyperphosphorylated at mitotic entry and localizes to centrosomal regions. BAG3 regulates, in an HSPB8-dependent manner, the timely congression of chromosomes to the metaphase plate by influencing the three-dimensional positioning of the mitotic spindle. Depletion of BAG3 caused defects in cell rounding at metaphase and dramatic blebbing of the cortex associated with abnormal spindle rotations. Similar defects were observed upon silencing of the autophagic receptor p62/SQSTM1 that contributes to BAG3-mediated selective autophagy pathway. Mitotic cells depleted of BAG3, HSPB8 or p62/SQSTM1 exhibited disorganized actin-rich retraction fibres, which are proposed to guide spindle orientation. Proper spindle positioning was rescued in BAG3-depleted cells upon addition of the lectin concanavalin A, which restores cortex rigidity. Together, our findings suggest the existence of a so-far unrecognized quality control mechanism involving BAG3, HSPB8 and p62/SQSTM1 for accurate remodelling of actin-based mitotic structures that guide spindle orientation.

Apple F-box Protein MdMAX2 Regulates Plant Photomorphogenesis and Stress Response

Directory of Open Access Journals (Sweden)

Jian-Ping An

2016-11-01

Full Text Available MAX2 (MORE AXILLARY GROWTH2 is involved in diverse physiological processes, including photomorphogenesis, the abiotic stress response, as well as karrikin and strigolactone signaling-mediated shoot branching. In this study, MdMAX2, an F-box protein that is a homolog of Arabidopsis MAX2, was identified and characterized. Overexpression of MdMAX2 in apple calli enhanced the accumulation of anthocyanin. Ectopic expression of MdMAX2 in Arabidopsis exhibited photomorphogenesis phenotypes, including increased anthocyanin content and decreased hypocotyl length. Further study indicated that MdMAX2 might promote plant photomorphogenesis by affecting the auxin signaling as well as other plant hormones. Transcripts of MdMAX2 were noticeably up-regulated in response to NaCl and Mannitol treatments. Moreover, compared with the wild type, the MdMAX2-overexpressing apple calli and Arabidopsis exhibited increased tolerance to salt and drought stresses. Taken together, these results suggest that MdMAX2 plays a positive regulatory role in plant photomorphogenesis and stress response.

Combined speed endurance and endurance exercise amplify the exercise-induced PGC-1α and PDK4 mRNA response in trained human muscle

DEFF Research Database (Denmark)

Skovgaard, Casper; Brandt, Nina; Pilegaard, Henriette

2016-01-01

The aim of this study was to investigate the mRNA response related to mitochondrial biogenesis, metabolism, angiogenesis, and myogenesis in trained human skeletal muscle to speed endurance exercise (S), endurance exercise (E), and speed endurance followed by endurance exercise (S + E). Seventeen...... trained male subjects (maximum oxygen uptake (VO2-max): 57.2 ± 3.7 (mean ± SD) mL·min(-1)·kg(-1)) performed S (6 × 30 sec all-out), E (60 min ~60% VO2-max), and S + E on a cycle ergometer on separate occasions. Muscle biopsies were obtained at rest and 1, 2, and 3 h after the speed endurance exercise (S...... and S + E) and at rest, 0, 1, and 2 h after exercise in E In S and S + E, muscle peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1α) and pyruvate dehydrogenase kinase-4 (PDK4) mRNA were higher (P endurance exercise than at rest. Muscle PGC-1α and PDK4 m...

Max Scheler's Phenomenology of Interrelation

African Journals Online (AJOL)

denise

German phenomenologist and sociologist Max Scheler accorded sympathy a central role in his philosophy .... process of deliberation or ask myself how the other person might be feeling .... Scheler believes that Nietzsche mistakenly identifies.

President Ilves kohtus Max Jakobsoniga

Index Scriptorium Estoniae

2008-01-01

President Toomas Hendrik Ilves ja Soome tuntud diplomaat Max Jakobson arutasid 16. septembril 2008 Tallinnas toimunud kohtumisel julgeolekuolukorda Euroopas pärast Venemaa-Gruusia sõda, Euroopa Liidu suhteid Venemaaga ja NATO tulevikku

Max Weber's Critique of the Bureaucratisation of Education

Science.gov (United States)

Madan, Amman

2014-01-01

In this commentary, the author discusses the critique by Max Weber and his views on bureaucratisation of education. The modern school, said Max Weber (1864-1920) over a hundred years ago, has as its educational ideal the bureaucrat and no longer the cultivated elite of older times. The shift to modernity and to its characteristic institution, the…

Topography of Slow Sigma Power during Sleep is Associated with Processing Speed in Preschool Children

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Margaret R. Doucette

2015-11-01

Full Text Available Cognitive development is influenced by maturational changes in processing speed, a construct reflecting the rapidity of executing cognitive operations. Although cognitive ability and processing speed are linked to spindles and sigma power in the sleep electroencephalogram (EEG, little is known about such associations in early childhood, a time of major neuronal refinement. We calculated EEG power for slow (10–13 Hz and fast (13.25–17 Hz sigma power from all-night high-density electroencephalography (EEG in a cross-sectional sample of healthy preschool children (n = 10, 4.3 ± 1.0 years. Processing speed was assessed as simple reaction time. On average, reaction time was 1409 ± 251 ms; slow sigma power was 4.0 ± 1.5 μV2; and fast sigma power was 0.9 ± 0.2 μV2. Both slow and fast sigma power predominated over central areas. Only slow sigma power was correlated with processing speed in a large parietal electrode cluster (p < 0.05, r ranging from −0.6 to −0.8, such that greater power predicted faster reaction time. Our findings indicate regional correlates between sigma power and processing speed that are specific to early childhood and provide novel insights into the neurobiological features of the EEG that may underlie developing cognitive abilities.

Mucinous tubular and spindle cell carcinoma of kidney: A rare case report and review of the literature

Directory of Open Access Journals (Sweden)

Geramizadeh Bita

2009-10-01

Full Text Available Low grade mucinous tubular and spindle cell carcinoma of kidney was newly established as a distinct renal cell carcinoma in the World Health Organization (WHO classification of 2004. Until now, less than 60 cases have been reported and the largest series represented approximately 15 patients with this type of tumor. Herein, we report a case of mucinous tubular and spindle cell carcinoma in a 63-year-old male presented with right flank pain which was diagnosed after nephrectomy. Pathologists should consider this diagnosis and its spectrum of histopathologic features in mind to ensure an accurate diagnosis.

Critical Importance of Protein 4.1 in Centrosome and Mitiotic Spindle Aberrations in Breast Cancer Pathogenesis

National Research Council Canada - National Science Library

Krauss, Sharon W

2005-01-01

Important pathological hallmarks of many breast cancers include centrosome amplification, spindle pole defects leading to aberrant chromosome segregation, altered nucleoskeletal proteins and perturbed cytokinesis...

MaxSynBio - Avenues towards creating cells from the bottom up.

Science.gov (United States)

Schwille, Petra; Spatz, Joachim; Landfester, Katharina; Bodenschatz, Eberhard; Herminghaus, Stephan; Sourjik, Victor; Erb, Tobias; Bastiaens, Philippe; Lipowsky, Reinhard; Hyman, Anthony; Dabrock, Peter; Baret, Jean-Christophe; Vidakovic-Koch, Tanja; Bieling, Peter; Dimova, Rumiana; Mutschler, Hannes; Robinson, Tom; Tang, Dora; Wegner, Seraphine; Sundmacher, Kai

2018-05-11

A large Max Planck-based German research consortium ('MaxSynBio') was formed to investigate living systems from a fundamental perspective. The research program of MaxSynBio relies solely on the bottom-up approach to Synthetic Biology. MaxSynBio focuses on the detailed analysis and understanding of essential processes of life, via their modular reconstitution in minimal synthetic systems. The ultimate goal is to construct a basic living unit entirely from non-living components. The fundamental insights gained from the activities in MaxSynBio can eventually be utilized for establishing a new generation of biotechnological processes, which would be based on synthetic cell constructs that replace natural cells currently used in conventional biotechnology. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spindle cell oncocytoma of adenohypophysis: Cytogenetics and β-catenin findings with pathology differential diagnosis and review of the literature

Directory of Open Access Journals (Sweden)

Jianwu Xie

2017-09-01

Full Text Available Spindle cell oncocytoma (SCO is an extremely rare neoplasm arising in the anterior pituitary. We report comprehensive pathological description of a case of SCO in a 60 year-old male who presented with nausea, vomiting and severe hyponatremia, and pan hypopituitarism. Magnetic resonance imaging (MRI showed a 3.1 × 2.3 × 2.0 cm homogeneously enhancing bilobed mass within the sella turcica and suprasellar cistern. Intraoperative frozen section and touch imprint cytology showed cohesive spindle cells with abundant oncocytic cytoplasm. Histologic sections revealed the tumor was composed of interlacing fascicles of compact spindled cells with abundant dense oncocytic cytoplasm. There was no mitosis or necrosis present. Ki-67 index varied in areas, with an average of 3%. By immunohistochemistry (IHC, the tumor cells were negative for Cam5.2, AE1/3, neurofilament (NF, NeuN, glial fibrillary acidic protein (GFAP and synaptophysin, and strongly positive for vimentin, TTF-1 and EMA. S-100 showed focal weakly positivity. By electron microscopy (EM, the cytoplasm of the spindle cells contained numerous abundant, back-to-back, uniform, round, normal-sized mitochondria with long and lamellar cristae. Beta-catenin showed diffuse membranous and partial cytoplasmic positivity. Cytogenetic analysis showed extra copies of chromosome 1 (74%, up to 8 copies, and loss of chromosome 2 (35%. The histogenesis, classification and differential diagnosis are discussed.

Mammalian neurogenesis requires Treacle-Plk1 for precise control of spindle orientation, mitotic progression, and maintenance of neural progenitor cells.

Directory of Open Access Journals (Sweden)

Daisuke Sakai

Full Text Available The cerebral cortex is a specialized region of the brain that processes cognitive, motor, somatosensory, auditory, and visual functions. Its characteristic architecture and size is dependent upon the number of neurons generated during embryogenesis and has been postulated to be governed by symmetric versus asymmetric cell divisions, which mediate the balance between progenitor cell maintenance and neuron differentiation, respectively. The mechanistic importance of spindle orientation remains controversial, hence there is considerable interest in understanding how neural progenitor cell mitosis is controlled during neurogenesis. We discovered that Treacle, which is encoded by the Tcof1 gene, is a novel centrosome- and kinetochore-associated protein that is critical for spindle fidelity and mitotic progression. Tcof1/Treacle loss-of-function disrupts spindle orientation and cell cycle progression, which perturbs the maintenance, proliferation, and localization of neural progenitors during cortical neurogenesis. Consistent with this, Tcof1(+/- mice exhibit reduced brain size as a consequence of defects in neural progenitor maintenance. We determined that Treacle elicits its effect via a direct interaction with Polo-like kinase1 (Plk1, and furthermore we discovered novel in vivo roles for Plk1 in governing mitotic progression and spindle orientation in the developing mammalian cortex. Increased asymmetric cell division, however, did not promote increased neuronal differentiation. Collectively our research has therefore identified Treacle and Plk1 as novel in vivo regulators of spindle fidelity, mitotic progression, and proliferation in the maintenance and localization of neural progenitor cells. Together, Treacle and Plk1 are critically required for proper cortical neurogenesis, which has important implications in the regulation of mammalian brain size and the pathogenesis of congenital neurodevelopmental disorders such as microcephaly.

The use and misuse of V(c,max) in Earth System Models.

Science.gov (United States)

Rogers, Alistair

2014-02-01

Earth System Models (ESMs) aim to project global change. Central to this aim is the need to accurately model global carbon fluxes. Photosynthetic carbon dioxide assimilation by the terrestrial biosphere is the largest of these fluxes, and in many ESMs is represented by the Farquhar, von Caemmerer and Berry (FvCB) model of photosynthesis. The maximum rate of carboxylation by the enzyme Rubisco, commonly termed V c,max, is a key parameter in the FvCB model. This study investigated the derivation of the values of V c,max used to represent different plant functional types (PFTs) in ESMs. Four methods for estimating V c,max were identified; (1) an empirical or (2) mechanistic relationship was used to relate V c,max to leaf N content, (3) V c,max was estimated using an approach based on the optimization of photosynthesis and respiration or (4) calibration of a user-defined V c,max to obtain a target model output. Despite representing the same PFTs, the land model components of ESMs were parameterized with a wide range of values for V c,max (-46 to +77% of the PFT mean). In many cases, parameterization was based on limited data sets and poorly defined coefficients that were used to adjust model parameters and set PFT-specific values for V c,max. Examination of the models that linked leaf N mechanistically to V c,max identified potential changes to fixed parameters that collectively would decrease V c,max by 31% in C3 plants and 11% in C4 plants. Plant trait data bases are now available that offer an excellent opportunity for models to update PFT-specific parameters used to estimate V c,max. However, data for parameterizing some PFTs, particularly those in the Tropics and the Arctic are either highly variable or largely absent.

Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis.

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Chou, En-Ju; Hung, Liang-Yi; Tang, Chieh-Ju C; Hsu, Wen-Bin; Wu, Hsin-Yi; Liao, Pao-Chi; Tang, Tang K

2016-03-29

CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. Interestingly, the dispersal of the PCM was effectively rescued by ectopic expression of wild-type CPAP or a phospho-mimic CPAP-S467D mutant, but not a non-phosphorylated CPAP-S467A mutant. Finally, we found that CPAP-S467D has a low affinity for microtubule binding but a high affinity for PCM proteins. Together, our results support a model wherein CPAP is required for proper mitotic progression, and phosphorylation of CPAP by Aurora-A is essential for maintaining spindle pole integrity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Mto2 multisite phosphorylation inactivates non-spindle microtubule nucleation complexes during mitosis

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Borek, Weronika E.; Groocock, Lynda M.; Samejima, Itaru; Zou, Juan; de Lima Alves, Flavia; Rappsilber, Juri; Sawin, Kenneth E.

2015-01-01

Microtubule nucleation is highly regulated during the eukaryotic cell cycle, but the underlying molecular mechanisms are largely unknown. During mitosis in fission yeast Schizosaccharomyces pombe, cytoplasmic microtubule nucleation ceases simultaneously with intranuclear mitotic spindle assembly. Cytoplasmic nucleation depends on the Mto1/2 complex, which binds and activates the γ-tubulin complex and also recruits the γ-tubulin complex to both centrosomal (spindle pole body) and non-centrosomal sites. Here we show that the Mto1/2 complex disassembles during mitosis, coincident with hyperphosphorylation of Mto2 protein. By mapping and mutating multiple Mto2 phosphorylation sites, we generate mto2-phosphomutant strains with enhanced Mto1/2 complex stability, interaction with the γ-tubulin complex and microtubule nucleation activity. A mutant with 24 phosphorylation sites mutated to alanine, mto2[24A], retains interphase-like behaviour even in mitotic cells. This provides a molecular-level understanding of how phosphorylation ‘switches off' microtubule nucleation complexes during the cell cycle and, more broadly, illuminates mechanisms regulating non-centrosomal microtubule nucleation. PMID:26243668

The Spindle Assembly Checkpoint in Arabidopsis Is Rapidly Shut Off during Severe Stress.

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Komaki, Shinichiro; Schnittger, Arp

2017-10-23

The spindle assembly checkpoint (SAC) in animals and yeast assures equal segregation of chromosomes during cell division. The prevalent occurrence of polyploidy in flowering plants together with the observation that many plants can be readily forced to double their genomes by application of microtubule drugs raises the question of whether plants have a proper SAC. Here, we provide a functional framework of the core SAC proteins in Arabidopsis. We reveal that Arabidopsis will delay mitosis in a SAC-dependent manner if the spindle is perturbed. However, we also show that the molecular architecture of the SAC is unique in plants. Moreover, the SAC is short-lived and cannot stay active for more than 2 hr, after which the cell cycle is reset. This resetting opens the possibility for genome duplications and raises the hypothesis that a rapid termination of a SAC-induced mitotic arrest provides an adaptive advantage for plants impacting plant genome evolution. Copyright © 2017 Elsevier Inc. All rights reserved.

Spindle cell carcinoma of the breast as complex cystic lesion: a case report

International Nuclear Information System (INIS)

Kitada, Masahiro; Hayashi, Satoshi; Matsuda, Yoshinari; Ishibashi, Kei; Oikawa, Keisuke; Miyokawa, Naoyuki

2014-01-01

Spindle cell carcinoma of the breast is a rare tumor. This tumor can proliferate rapidly and cause cystic changes because of internal tissue necrosis. We evaluated a 54-year-old woman with right breast lump. Mammography showed a category four mass with a diameter of 2.5 cm. Ultrasonography (US) revealed a complex cystic lesion, and fine-needle aspiration (FNA) cytology demonstrated bloody fluid and malignant cells. Partial breast resection and sentinel lymph node biopsy were performed. Immunohistology revealed spindle cells with positive results for cytokeratin (AE1/AE3) and vimentin, partially positive results for s-100, and negative results for desmin and α-actin. The pathological stage was IIA, and biochemical characterization showed that the tumor was triple negative. Six courses of FEC-100 chemotherapy (5-fluorouracil 500 mg/m 2 , epirubicin 100 mg/m 2 , and cyclophosphamide 500 mg/m 2 ) were administered. Radiotherapy was performed. This case is discussed with reference to the literature

Digital logic circuit design with ALTERA MAX+PLUS II

International Nuclear Information System (INIS)

Lee, Seung Ho; Park, Yong Su; Lee, Ju Heon

2006-03-01

Contents of this book are the kinds of integrated circuit, design process of integrated circuit, introduction of ALTERA MAX+PLUS II, designing logic circuit with VHDL of ALTERA MAX+PLUS II, grammar and practice of VHDL of ALTERA MAX+PLUS II, design for adder, subtractor, parallel binary subtractor, BCD design, CLA design, code converter design, ALU design, register design, counter design, accumulator design, state machine design, frequency divider design, circuit design with TENMILLION counter, LCD module, circuit design for control the outside RAM in training kit and introduction for HEB-DTK-20K-240/HBE-DTK-IOK.

Synthesis, structural and optical properties of ZnO spindle/reduced graphene oxide composites with enhanced photocatalytic activity under visible light irradiation

Science.gov (United States)

Prabhu, S.; Pudukudy, M.; Sohila, S.; Harish, S.; Navaneethan, M.; Navaneethan, D.; Ramesh, R.; Hayakawa, Y.

2018-05-01

In the present work, spindle-shaped ZnO and reduced graphene oxide sheets were successfully synthesized by a hydrothermal method and then ZnO/r-GO composite was prepared by a direct solution mixing method. Various characterization results confirmed the interior and surface decoration of spindle-shaped ZnO on the reduced graphene oxide sheets. The phase formation, crystalline structure, morphology, surface states and optical properties were characterized using Powder X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectroscopy. The X-ray diffraction analysis showed the formation of the hexagonal wurtzite crystalline structure of ZnO with high crystalline quality. The band gap of the ZnO/r-GO composite was found to be low (3.03eV) compared to the band gap of spindle shaped ZnO (3.13 eV), as calculated from optical studies. The spindle-like morphology of the single crystalline ZnO was clearly shown in the electron microscopic images. The chemical bonding and surface states of the samples were studied using XPS measurement. Moreover, a possible growth mechanism for the ZnO spindle was proposed. The catalytic activity of the as-synthesized samples was evaluated for the photodegradation of methylene blue under visible light irradiation. Among the synthesized samples, the ZnO/r-GO composite showed higher degradation efficiency of 93% and successfully reused for four consecutive run without any activity loss.

Xenopus laevis Kif18A is a highly processive kinesin required for meiotic spindle integrity

Directory of Open Access Journals (Sweden)

Martin M. Möckel

2017-04-01

Full Text Available The assembly and functionality of the mitotic spindle depends on the coordinated activities of microtubule-associated motor proteins of the dynein and kinesin superfamily. Our current understanding of the function of motor proteins is significantly shaped by studies using Xenopus laevis egg extract as its open structure allows complex experimental manipulations hardly feasible in other model systems. Yet, the Kinesin-8 orthologue of human Kif18A has not been described in Xenopus laevis so far. Here, we report the cloning and characterization of Xenopus laevis (Xl Kif18A. Xenopus Kif18A is expressed during oocyte maturation and its depletion from meiotic egg extract results in severe spindle defects. These defects can be rescued by wild-type Kif18A, but not Kif18A lacking motor activity or the C-terminus. Single-molecule microscopy assays revealed that Xl_Kif18A possesses high processivity, which depends on an additional C-terminal microtubule-binding site. Human tissue culture cells depleted of endogenous Kif18A display mitotic defects, which can be rescued by wild-type, but not tail-less Xl_Kif18A. Thus, Xl_Kif18A is the functional orthologue of human Kif18A whose activity is essential for the correct function of meiotic spindles in Xenopus oocytes.

Max Reinharz (1923-2012)

CERN Multimedia

2013-01-01

Max Reinharz was born in Vienna, Austria, in 1923. In 1939 he was obliged to emigrate to the UK. At the beginning of the Second World War he was interned as an enemy alien and then deported to Australia at a time when the British feared an invasion by Germany. He returned to the UK in 1943 and joined the British Army. After he was demobbed in 1947, he studied physics in Vienna, where he took his doctorate in 1953.   Max Reinharz (centre) with Gordon Munday (left) and Henri Laporte (right) in 1979. After working in Brussels, at the physics Institute of Genoa and the University of Pisa, he joined CERN in 1960 as a fellow and in 1964 became a senior physicist in the NP Division. His name is associated with many publications, such as those of the CERN neutrino experiment and the CERN-Geneva-Lund collaboration to verify T symmetry conservation in lambda decays. He then joined a small team in the Proton Synchrotron Division (MPS) responsible for assisting external physics groups to prepare and i...

V-dotO2max prediction from multi-frequency bioelectrical impedance analysis

International Nuclear Information System (INIS)

Stahn, Alexander; Strobel, Günther; Terblanche, Elmarie

2008-01-01

Bioelectrical impedance analysis (BIA) has been shown to be highly related to skeletal muscle mass and blood volume, both of which are important determinants of maximal oxygen uptake (V-dotO 2max ). The aim of the present study was therefore to investigate the ability of whole-body and segmental multi-frequency BIA to improve current nonexercise V-dotO 2max prediction models. Data for V-dotO 2max (mL min −1 ), anthropometry, self-reported physical activity (PA-R) and BIA were collected in 115 men and women. Multiple linear regression analysis (MLR) was used to develop the most parsimonious prediction model. Segmental BIA was not superior to whole-body measurements. Correlation coefficients between V-dotO 2max and resistance indices were significantly higher at 500 kHz compared to 50 kHz (p 2max (r = 0.89). After adjusting for age, gender and PA-R, MLR revealed that the inclusion of intracellular resistance index was slightly, but significantly (p 2max ( −1 ). In short, whole-body BIA marginally improves the accuracy of nonexercise V-dotO 2max prediction models and its advantage is most pronounced in individuals with particularly low V-dotO 2max

Speed endurance training is a powerful stimulus for physiological adaptations and performance improvements of athletes

DEFF Research Database (Denmark)

Iaia, F. M.; Bangsbo, Jens

2010-01-01

the oxidative capacity and improve intense short-duration/repeated high-intensity exercise performance lasting 30 s to 4 min, as it occurs in a number of sports. When combined with a basic volume of training including some aerobic high-intensity sessions, speed endurance training is also useful in enhancing......The present article reviews the physiological and performance effects of speed endurance training consisting of exercise bouts at near maximal intensities in already trained subjects. Despite a reduction in training volume, speed endurance training of endurance-trained athletes can maintain...... performance during longer events, e.g. 40 K cycling and 10 K running. Athletes in team sports involving intense exercise actions and endurance aspects can also benefit from performing speed endurance training. These improvements don't appear to depend on changes in maximum oxygen uptake (VO2max), muscle...

The SUMO protease SENP1 is required for cohesion maintenance and mitotic arrest following spindle poison treatment

Energy Technology Data Exchange (ETDEWEB)

Era, Saho [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Abe, Takuya; Arakawa, Hiroshi [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Kobayashi, Shunsuke [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Szakal, Barnabas [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Yoshikawa, Yusuke; Motegi, Akira; Takeda, Shunichi [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Branzei, Dana, E-mail: dana.branzei@ifom.eu [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy)

2012-09-28

Highlights: Black-Right-Pointing-Pointer SENP1 knockout chicken DT40 cells are hypersensitive to spindle poisons. Black-Right-Pointing-Pointer Spindle poison treatment of SENP1{sup -/-} cells leads to increased mitotic slippage. Black-Right-Pointing-Pointer Mitotic slippage in SENP1{sup -/-} cells associates with apoptosis and endoreplication. Black-Right-Pointing-Pointer SENP1 counteracts sister chromatid separation during mitotic arrest. Black-Right-Pointing-Pointer Plk1-mediated cohesion down-regulation is involved in colcemid cytotoxicity. -- Abstract: SUMO conjugation is a reversible posttranslational modification that regulates protein function. SENP1 is one of the six SUMO-specific proteases present in vertebrate cells and its altered expression is observed in several carcinomas. To characterize SENP1 role in genome integrity, we generated Senp1 knockout chicken DT40 cells. SENP1{sup -/-} cells show normal proliferation, but are sensitive to spindle poisons. This hypersensitivity correlates with increased sister chromatid separation, mitotic slippage, and apoptosis. To test whether the cohesion defect had a causal relationship with the observed mitotic events, we restored the cohesive status of sister chromatids by introducing the TOP2{alpha}{sup +/-} mutation, which leads to increased catenation, or by inhibiting Plk1 and Aurora B kinases that promote cohesin release from chromosomes during prolonged mitotic arrest. Although TOP2{alpha} is SUMOylated during mitosis, the TOP2{alpha}{sup +/-} mutation had no obvious effect. By contrast, inhibition of Plk1 or Aurora B rescued the hypersensitivity of SENP1{sup -/-} cells to colcemid. In conclusion, we identify SENP1 as a novel factor required for mitotic arrest and cohesion maintenance during prolonged mitotic arrest induced by spindle poisons.

Synthesis of spindle-shaped AgI/TiO{sub 2} nanoparticles with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Yang, Liu; Gao, Minggang; Dai, Bin; Guo, Xuhong; Liu, Zhiyong; Peng, Banghua, E-mail: banghuapeng@hotmail.com

2016-11-15

Highlights: • Nanoporous spindle-shaped AgI/TiO{sub 2} was synthesized by the solvothermal approach. • The spindle-shaped TiO{sub 2} was an excellent support for loading nanoparticles, such as AgI, transferring electrons quickly from AgI, which is beneficial for stabilizing the AgI. • AgI/TiO{sub 2} nanoparticles showed enhanced absorption intensity in the visible region and exhibited excellent photocatalytic activity. - Abstract: A novel synthetic route has been developed to prepare silver iodide (AgI) loaded spindle-shaped TiO{sub 2} nanoparticles (NPs). The morphology and crystallinity characterization revealed that small AgI NPs, with an average diameter of 15 nm were dispersed on the surface and interior of nanoporous anatase TiO{sub 2} support. High-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) surface area, Raman and X-ray photoelectron spectroscopy (XPS) were used to identify the nanoporous structure of TiO{sub 2} and the existence of AgI NPs. Diffuse reflectance spectra (DRS) showed that AgI/TiO{sub 2} composite exhibited a remarkable enhancement of visible light absorption, which is ascribed to the addition of AgI. For illustrating the superior property of this hybrid as photocatalyst, the degradation experiments were carried out for processing rhodamine B (RhB) solution under visible light irradiation and it was found that the photocatalytic activity was dramatically improved for AgI/TiO{sub 2} compared with nanoporous TiO{sub 2} and commercial P25 TiO{sub 2}. The enhanced photocatalytic properties could be attributed to the large surface area of porous TiO{sub 2}, good stability of AgI particles, and the effective charge separation due to the synergetic effect between AgI and TiO{sub 2} that can facilitate the separation of electron-hole pairs. Our novel composite based on nanoporous spindle-shaped TiO{sub 2} represents a promising new pathway for the design of high-performance photocatalysts for environmental

The nucleoporin MEL-28 promotes RanGTP-dependent γ-tubulin recruitment and microtubule nucleation in mitotic spindle formation.

Science.gov (United States)

Yokoyama, Hideki; Koch, Birgit; Walczak, Rudolf; Ciray-Duygu, Fulya; González-Sánchez, Juan Carlos; Devos, Damien P; Mattaj, Iain W; Gruss, Oliver J

2014-01-01

The GTP-bound form of the Ran GTPase (RanGTP), produced around chromosomes, drives nuclear envelope and nuclear pore complex (NPC) re-assembly after mitosis. The nucleoporin MEL-28/ELYS binds chromatin in a RanGTP-regulated manner and acts to seed NPC assembly. Here we show that, upon mitotic NPC disassembly, MEL-28 dissociates from chromatin and re-localizes to spindle microtubules and kinetochores. MEL-28 directly binds microtubules in a RanGTP-regulated way via its C-terminal chromatin-binding domain. Using Xenopus egg extracts, we demonstrate that MEL-28 is essential for RanGTP-dependent microtubule nucleation and spindle assembly, independent of its function in NPC assembly. Specifically, MEL-28 interacts with the γ-tubulin ring complex and recruits it to microtubule nucleation sites. Our data identify MEL-28 as a RanGTP target that functions throughout the cell cycle. Its cell cycle-dependent binding to chromatin or microtubules discriminates MEL-28 functions in interphase and mitosis, and ensures that spindle assembly occurs only after NPC breakdown.

Compositions of (max, +) automata

Czech Academy of Sciences Publication Activity Database

Lahaye, S.; Komenda, Jan; Boimond, J.-L.

2015-01-01

Roč. 25, 1-2 (2015), s. 323-344 ISSN 0924-6703 R&D Projects: GA ČR(CZ) GAP103/11/0517 Institutional support: RVO:67985840 Keywords : (max,+) automata * synchronous product * asynchronous product Subject RIV: BA - General Mathematics Impact factor: 1.268, year: 2015 http://link.springer.com/article/10.1007/s10626-014-0186-6

Reachability analysis for timed automata using max-plus algebra

DEFF Research Database (Denmark)

Lu, Qi; Madsen, Michael; Milata, Martin

2012-01-01

We show that max-plus polyhedra are usable as a data structure in reachability analysis of timed automata. Drawing inspiration from the extensive work that has been done on difference bound matrices, as well as previous work on max-plus polyhedra in other areas, we develop the algorithms needed...

Machinability evaluation of titanium alloys (Part 2)--Analyses of cutting force and spindle motor current.

Science.gov (United States)

Kikuchi, Masafumi; Okuno, Osamu

2004-12-01

To establish a method of determining the machinability of dental materials for CAD/CAM systems, the machinability of titanium, two titanium alloys (Ti-6Al-4V and Ti-6Al-7Nb), and free-cutting brass was evaluated through cutting force and spindle motor current. The metals were slotted using a milling machine and square end mills at four cutting conditions. Both the static and dynamic components of the cutting force represented well the machinability of the metals tested: the machinability of Ti-6Al-4V and Ti-6Al-7Nb was worse than that of titanium, while that of free-cutting brass was better. On the other hand, the results indicated that the spindle motor current was not sensitive enough to detect the material difference among the titanium and its alloys.

Diversity of endophytic fungi in Glycine max.

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Fernandes, Elio Gomes; Pereira, Olinto Liparini; da Silva, Cynthia Cânedo; Bento, Claudia Braga Pereira; de Queiroz, Marisa Vieira

2015-12-01

Endophytic fungi are microorganisms that live within plant tissues without causing disease during part of their life cycle. With the isolation and identification of these fungi, new species are being discovered, and ecological relationships with their hosts have also been studied. In Glycine max, limited studies have investigated the isolation and distribution of endophytic fungi throughout leaves and roots. The distribution of these fungi in various plant organs differs in diversity and abundance, even when analyzed using molecular techniques that can evaluate fungal communities in different parts of the plants, such as denaturing gradient gel electrophoresis (DGGE). Our results show there is greater species richness of culturable endophytic filamentous fungi in the leaves G. max as compared to roots. Additionally, the leaves had high values for diversity indices, i.e. Simpsons, Shannon and Equitability. Conversely, dominance index was higher in roots as compared to leaves. The fungi Ampelomyces sp., Cladosporium cladosporioides, Colletotrichum gloeosporioides, Diaporthe helianthi, Guignardia mangiferae and Phoma sp. were more frequently isolated from the leaves, whereas the fungi Fusarium oxysporum, Fusarium solani and Fusarium sp. were prevalent in the roots. However, by evaluating the two communities by DGGE, we concluded that the species richness was higher in the roots than in the leaves. UPGMA analysis showed consistent clustering of isolates; however, the fungus Leptospora rubella, which belongs to the order Dothideales, was grouped among species of the order Pleosporales. The presence of endophytic Fusarium species in G. max roots is unsurprising, since Fusarium spp. isolates have been previously described as endophyte in other reports. However, it remains to be determined whether the G. max Fusarium endophytes are latent pathogens or non-pathogenic forms that benefit the plant. This study provides a broader knowledge of the distribution of the fungal

Max Weber and Robert Michels.

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Scaff, Lawrence A.

1981-01-01

This paper investigates the unique intellectual partnership of Max Weber and Robert Michels, with particular emphasis on Weber's influence on Michel's inquiry into the sociology of parties and organization. Concludes with an evaluation of the import of Weber's critique of Michels' work. (DB)

Bir1 Deletion Causes Malfunction of the Spindle Assembly Checkpoint and Apoptosis in Yeast

International Nuclear Information System (INIS)

Ren, Qun; Liou, Liang-Chun; Gao, Qiuqiang; Bao, Xiaoming; Zhang, Zhaojie

2012-01-01

Cell division in yeast is a highly regulated and well studied event. Various checkpoints are placed throughout the cell cycle to ensure faithful segregation of sister chromatids. Unexpected events, such as DNA damage or oxidative stress, cause the activation of checkpoint(s) and cell cycle arrest. Malfunction of the checkpoints may induce cell death. We previously showed that under oxidative stress, the budding yeast cohesin Mcd1, a homolog of human Rad21, was cleaved by the caspase-like protease Esp1. The cleaved Mcd1 C-terminal fragment was then translocated to mitochondria, causing apoptotic cell death. In the present study, we demonstrated that Bir1 plays an important role in spindle assembly checkpoint and cell death. Similar to H 2 O 2 treatment, deletion of BIR1 using a BIR1-degron strain caused degradation of the securin Pds1, which binds and inactivates Esp1 until metaphase-anaphase transition in a normal cell cycle. BIR1 deletion caused an increase level of ROS and mis-location of Bub1, a major protein for spindle assembly checkpoint. In wild type, Bub1 was located at the kinetochores, but was primarily in the cytoplasm in bir1 deletion strain. When BIR1 was deleted, addition of nocodazole was unable to retain the Bub1 localization on kinetochores, further suggesting that Bir1 is required to activate and maintain the spindle assembly checkpoint. Our study suggests that the BIR1 function in cell cycle regulation works in concert with its anti-apoptosis function.

Depletion of a Drosophila homolog of yeast Sup35p disrupts spindle assembly, chromosome segregation, and cytokinesis during male meiosis.

Science.gov (United States)

Basu, J; Williams, B C; Li, Z; Williams, E V; Goldberg, M L

1998-01-01

In the course of a genetic screen for male-sterile mutations in Drosophila affecting chromosome segregation during the meiotic divisions in spermatocytes, we identified the mutation dsup35(63D). Examination of mutant testes showed that chromosome misbehavior was a consequence of major disruptions in meiotic spindle assembly. These perturbations included problems in aster formation, separation, and migration around the nuclear envelope; aberrations in spindle organization and integrity; and disappearance of the ana/telophase central spindle, which in turn disrupts cytokinesis. The dsup35(63D) mutation is caused by a P element insertion that affects, specifically in the testis, the expression of a gene (dsup35) encoding the Drosophila homolog of the yeast Sup35p and Xenopus eRF3 proteins. These proteins are involved in the termination of polypeptide synthesis on ribosomes, but previous studies have suggested that Sup35p and closely related proteins of the same family also interact directly with microtubules. An affinity-purified antibody directed against the product of the dsup35 gene was prepared; interestingly, this antibody specifically labels primary spermatocytes in one or two discrete foci of unknown structure within the nucleoplasm. We discuss how depletion of the dsup35 gene product in spermatocytes might lead to the global disruptions in meiotic spindle assembly seen in mutant spermatocytes.

Dgp71WD is required for the assembly of the acentrosomal Meiosis I spindle, and is not a general targeting factor for the γ-TuRC

Directory of Open Access Journals (Sweden)

Richard F. Reschen

2012-03-01

Dgp71WD/Nedd1 proteins are essential for mitotic spindle formation. In human cells, Nedd1 targets γ-tubulin to both centrosomes and spindles, but in other organisms the function of Dgp71WD/Nedd1 is less clear. In Drosophila cells, Dgp71WD plays a major part in targeting γ-tubulin to spindles, but not centrosomes, while in Xenopus egg extracts, Nedd1 acts as a more general microtubule (MT organiser that can function independently of γ-tubulin. The interpretation of these studies, however, is complicated by the fact that some residual Dgp71WD/Nedd1 is likely present in the cells/extracts analysed. Here we generate a Dgp71WD null mutant lacking all but the last 12 nucleotides of coding sequence. The complete loss of Dgp71WD has no quantifiable effect on γ-tubulin or Centrosomin recruitment to the centrosome in larval brain cells. The recruitment of γ-tubulin to spindle MTs, however, is severely impaired, and spindle MT density is reduced in a manner that is indistinguishable from cells lacking Augmin or γ-TuRC function. In contrast, the absence of Dgp71WD leads to defects in the assembly of the acentrosomal female Meiosis I spindle that are more severe than those seen in Augmin or γ-TuRC mutants, indicating that Dgp71WD has additional functions that are independent of these complexes in oocytes. Moreover, the localisation of bicoid RNA during oogenesis, which requires γ-TuRC function, is unperturbed in Dgp71WD120 mutants. Thus, Dgp71WD is not simply a general cofactor required for γ-TuRC and/or Augmin targeting, and it appears to have a crucial role independent of these complexes in the acentrosomal Meiosis I spindle.

Max Aub, crítico e historiador literario

Directory of Open Access Journals (Sweden)

Francisco Caudet

2002-11-01

Full Text Available On the basis of similarities and dissimilarities in the consideration of authors dealt with in Discurso de la novela española contemporánea, Francisco Caudet points out Max Aub's poetics of realism stated in both his critical studies and fiction. This essay shows that Aub's contribution to the study of Mexican and Spanish literature is outstanding, not only because of his socio-historical approach, but also because of a specific perspective. This does not mean writing a "history" of literature but rather connecting creative processes. Committed during his youth to the avant-garde, Max Aub shifts after the Civil War to a type of new realistic writing. The author highlights Max Aub's activity as a critic discussing and commenting his sources. Aub's critical essays cannot be detached from his personal ideas about literary theory and practice.

Molecular basis of APC/C regulation by the spindle assembly checkpoint

Science.gov (United States)

Zhang, Ziguo; Yang, Jing; Maslen, Sarah; Skehel, Mark; Barford, David

2016-01-01

In the dividing eukaryotic cell the spindle assembly checkpoint (SAC) ensures each daughter cell inherits an identical set of chromosomes. The SAC coordinates the correct attachment of sister chromatid kinetochores to the mitotic spindle with activation of the anaphase-promoting complex/cyclosome (APC/C), the E3 ubiquitin ligase that initiates chromosome separation. In response to unattached kinetochores, the SAC generates the mitotic checkpoint complex (MCC), a multimeric assembly that inhibits the APC/C, delaying chromosome segregation. Here, using cryo-electron microscopy we determined the near-atomic resolution structure of an APC/C-MCC complex (APC/CMCC). We reveal how degron-like sequences of the MCC subunit BubR1 block degron recognition sites on Cdc20, the APC/C coactivator subunit (Cdc20APC/C) responsible for substrate interactions. BubR1 also obstructs binding of UbcH10 (APC/C’s initiating E2) to repress APC/C ubiquitination activity. Conformational variability of the complex allows for UbcH10 association, and we show from a structure of APC/CMCC in complex with UbcH10 how the Cdc20 subunit intrinsic to the MCC (Cdc20MCC) is ubiquitinated, a process that results in APC/C reactivation when the SAC is silenced. PMID:27509861

Controllable synthesis of spindle-like ZnO nanostructures by a simple low-temperature aqueous solution route

International Nuclear Information System (INIS)

Lu Hongxia; Zhao Yunlong; Yu Xiujun; Chen Deliang; Zhang Liwei; Xu Hongliang; Yang Daoyuan; Wang Hailong; Zhang Rui

2011-01-01

Spindle-like ZnO nanostructures were successfully synthesized through direct precipitation of zinc acetate aqueous solution at 60 deg. C. Phase structure, morphology and microstructure of the products were investigated by X-ray diffraction, TG-DTA, FTIR and field emission scanning electron microscopy (FESEM). Result showed that hexagonal wurtzite structure ZnO nanostructures with about 100 nm in diameter and 100-200 nm in length were obtained. HMTA acted as a soft template in the process and played an important role in the formation of spindle-like ZnO nanostructures. Meanwhile, different morphologies were also obtained by altering synthetic temperature, additional agents and the ratios of Zn 2+ /OH - . Possible mechanism for the variations of morphology with synthesis parameters was also discussed in this paper.

Spindle orientation bias in gut epithelial stem cell compartments is lost in precancerous tissue

NARCIS (Netherlands)

Quyn, A.J.; Appleton, P.L.; Carey, F.A.; Steele, R.J.; Barker, N.; Clevers, H.; Ridgway, R.A.; Sansom, O.J.; Nathke, I.S.

2010-01-01

The importance of asymmetric divisions for stem cell function and maintenance is well established in the developing nervous system and the skin; however, its role in gut epithelium and its importance for tumorigenesis is still debated. We demonstrate alignment of mitotic spindles perpendicular to

Applying FDTD to the Coverage Prediction of WiMAX Femtocells

Directory of Open Access Journals (Sweden)

Valcarce Alvaro

2009-01-01

Full Text Available Femtocells, or home base stations, are a potential future solution for operators to increase indoor coverage and reduce network cost. In a real WiMAX femtocell deployment in residential areas covered by WiMAX macrocells, interference is very likely to occur both in the streets and certain indoor regions. Propagation models that take into account both the outdoor and indoor channel characteristics are thus necessary for the purpose of WiMAX network planning in the presence of femtocells. In this paper, the finite-difference time-domain (FDTD method is adapted for the computation of radiowave propagation predictions at WiMAX frequencies. This model is particularly suitable for the study of hybrid indoor/outdoor scenarios and thus well adapted for the case of WiMAX femtocells in residential environments. Two optimization methods are proposed for the reduction of the FDTD simulation time: the reduction of the simulation frequency for problem simplification and a parallel graphics processing units (GPUs implementation. The calibration of the model is then thoroughly described. First, the calibration of the absorbing boundary condition, necessary for proper coverage predictions, is presented. Then a calibration of the material parameters that minimizes the error function between simulation and real measurements is proposed. Finally, some mobile WiMAX system-level simulations that make use of the presented propagation model are presented to illustrate the applicability of the model for the study of femto- to macrointerference.

Effect of increased and maintained frequency of speed endurance training on performance and muscle adaptations in runners

DEFF Research Database (Denmark)

Skovgaard, Casper; Almquist, Nicki Winfield; Bangsbo, Jens

2017-01-01

The aim of the study was, in runners accustomed to speed endurance training (SET), to examine the effect of increased and maintained frequency of SET on performance and muscular adaptations. After familiarization (FAM) to SET, eighteen male (n=14) and female (n=4) runners (VO2-max: 57.3±3.4 ml·mi...

Critical Importance of Protein 4.1 in Centrosome and Mitotic Spindle Aberrations in Breast Cancer Pathogenesis

National Research Council Canada - National Science Library

Krauss, Sharon W

2006-01-01

We proposed to test the novel hypothesis that protein 4.1 is of critical importance to centrosome and mitotic spindle aberrations that directly impact aspects of breast cancer pathogenesis. We characterized...

Max Weber - bedaget og aktuel

DEFF Research Database (Denmark)

Eistrup, Jens

2010-01-01

undervisningsartiklen introducerer en række af Max Webers centrale begreber om herredømme, bureaukrati, social handlen, rationalitet og profession. dernæst illustreres hvorledes Webers begreber kan tjene til at belyse spændingsfeltet mellem politik og profession i en socialfaglig kontekst....

Tunnel Effect in CNNs: Image Reconstruction From Max-Switch Locations

DEFF Research Database (Denmark)

de La Roche Saint Andre, Matthieu; Rieger, Laura; Hannemose, Morten

2016-01-01

In this paper, we show that reconstruction of an image passed through a neural network is possible, using only the locations of the max pool activations. This was demonstrated with an architecture consisting of an encoder and a decoder. The decoder is a mirrored version of the encoder, where...... convolutions are replaced with deconvolutions and poolings are replaced with unpooling layers. The locations of the max pool switches are transmitted to the corresponding unpooling layer. The reconstruction is computed only from these switches without the use of feature values. Using only the max switch...

iamxt: Max-tree toolbox for image processing and analysis

Directory of Open Access Journals (Sweden)

Roberto Souza

2017-01-01

Full Text Available The iamxt is an array-based max-tree toolbox implemented in Python using the NumPy library for array processing. It has state of the art methods for building and processing the max-tree, and a large set of visualization tools that allow to view the tree and the contents of its nodes. The array-based programming style and max-tree representation used in the toolbox make it simple to use. The intended audience of this toolbox includes mathematical morphology students and researchers that want to develop research in the field and image processing researchers that need a toolbox simple to use and easy to integrate in their applications.

Effects of erythrocyte infusion on VO2max at high altitude

DEFF Research Database (Denmark)

Young, Jette Feveile; Sawka, M N; Muza, S R

1996-01-01

This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days...... of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control...... group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P

Localization of spindle checkpoint proteins in cells undergoing mitosis with unreplicated genomes.

Science.gov (United States)

Johnson, Mary Kathrine; Cooksey, Amanda M; Wise, Dwayne A

2008-11-01

CHO cells can be arrested with hydoxyurea at the beginning of the DNA synthesis phase of the cell cycle. Subsequent treatment with the xanthine, caffeine, induces cells to bypass the S-phase checkpoint and enter unscheduled mitosis [Schlegel and Pardee,1986, Science 232:1264-1266]. These treated cells build a normal spindle and distribute kinetochores, unattached to chromosomes, to their daughter cells [Brinkley et al.,1988, Nature 336:251-254; Zinkowski et al.,1991, J Cell Biol 113:1091-1110; Wise and Brinkley,1997, Cell Motil Cytoskeleton 36:291-302; Balczon et al.,2003, Chromosoma 112:96-102]. To investigate how these cells distribute kinetochores to daughter cells, we analyzed the spindle checkpoint components, Mad2, CENP-E, and the 3F3 phosphoepitope, using immunofluorescence and digital microscopy. Even though the kinetochores were unpaired and DNA was fragmented, the tension, alignment, and motor components of the checkpoint were found to be present and localized as predicted in prometaphase and metaphase. This unusual mitosis proves that a cell can successfully localize checkpoint proteins and divide even when kinetochores are unpaired and fragmented. (c) 2008 Wiley-Liss, Inc.

Few-layer molybdenum disulfide transistors and circuits for high-speed flexible electronics.

Science.gov (United States)

Cheng, Rui; Jiang, Shan; Chen, Yu; Liu, Yuan; Weiss, Nathan; Cheng, Hung-Chieh; Wu, Hao; Huang, Yu; Duan, Xiangfeng

2014-10-08

Two-dimensional layered materials, such as molybdenum disulfide, are emerging as an exciting material system for future electronics due to their unique electronic properties and atomically thin geometry. Here we report a systematic investigation of MoS2 transistors with optimized contact and device geometry, to achieve self-aligned devices with performance including an intrinsic gain over 30, an intrinsic cut-off frequency fT up to 42 GHz and a maximum oscillation frequency fMAX up to 50 GHz, exceeding the reported values for MoS2 transistors to date (fT~0.9 GHz, fMAX~1 GHz). Our results show that logic inverters or radio frequency amplifiers can be formed by integrating multiple MoS2 transistors on quartz or flexible substrates with voltage gain in the gigahertz regime. This study demonstrates the potential of two-dimensional layered semiconductors for high-speed flexible electronics.

Few-layer molybdenum disulfide transistors and circuits for high-speed flexible electronics

Science.gov (United States)

Cheng, Rui; Jiang, Shan; Chen, Yu; Liu, Yuan; Weiss, Nathan; Cheng, Hung-Chieh; Wu, Hao; Huang, Yu; Duan, Xiangfeng

2014-01-01

Two-dimensional layered materials, such as molybdenum disulfide, are emerging as an exciting material system for future electronics due to their unique electronic properties and atomically thin geometry. Here we report a systematic investigation of MoS2 transistors with optimized contact and device geometry, to achieve self-aligned devices with performance including an intrinsic gain over 30, an intrinsic cut-off frequency fT up to 42 GHz and a maximum oscillation frequency fMAX up to 50 GHz, exceeding the reported values for MoS2 transistors to date (fT ~ 0.9 GHz, fMAX ~ 1 GHz). Our results show that logic inverters or radio frequency amplifiers can be formed by integrating multiple MoS2 transistors on quartz or flexible substrates with voltage gain in the gigahertz regime. This study demonstrates the potential of two-dimensional layered semiconductors for high-speed flexible electronics. PMID:25295573

A comparative study of using spindle motor power and eddy current for the detection of tool conditions in milling processes

OpenAIRE

Abbass, JK; Al-Habaibeh, A

2015-01-01

This paper investigates the use of the power of the driving motor of a CNC spindle in comparison to two perpendicular eddy current sensors for the detection of tool wear in milling processes. Monitoring the power through the current profile is a low cost system which has been utilised in this study as an attempt to detect the fluctuation in the motor load as a result of the conditions of the cutting tool. Eddy current sensors are dedicated sensors that are installed on the spindle to measure ...

A short period undulator for MAX

International Nuclear Information System (INIS)

Ahola, H.; Meinander, T.

1992-01-01

A hybrid undulator for generation of high brilliance synchrotron radiation in the photon energy range of 60--600 eV at the 550 MeV electron storage ring MAX in Lund, Sweden has been designed and built at the Technical Research Centre of Finland in close collaboration with MAX-lab of Lund University. At the rather modest electron energy of MAX this photon energy range can be reached only by an undulator featuring a fairly short period and the smallest possible magnetic gap. Even then, higher harmonics (up to the 13th) of the radiation spectrum must be utilized. An optimization of the magnetic design resulted in a hybrid configuration of NdFeB magnets and soft iron poles with a period of 24 mm and a minimum magnetic gap of 7--10 mm. A variable-gap vacuum chamber allows reduction of the vacuum gap from a maximum of 20 mm, needed for injection, down to 6 mm during stored beam operation. A special design of this chamber permits a magnetic gap between pole tips that is only 1 mm larger than the vacuum gap. Adequate field uniformity was ensured by calibration of magnets to equal strength at their true operating point and verification of the homogeneity of their magnetization. Magnetic measurements included Hall probe scans of the undulator field and flip coil evaluations of the field integral

Estimated VO2max and its corresponding velocity predict performance of amateur runners

Directory of Open Access Journals (Sweden)

Bruno Ribeiro Ramalho Oliveira

2012-03-01

Full Text Available In recent years, there has been a substantial increase in the number of runners, with a proportional increase in their involvement in amateur street competition. Identification of the determinants of performance in this population appears necessary for optimization of time devoted to training. The objective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max, critical velocity (CV and VO2max velocity (VVO2max and athletic performance in the 3.6 km (uphill and 10 and 21.1 km (flatland events. Twelve amateur runners (nine male, mean age 36 ± 5 years underwent five tests: 1 and 5 km race on level ground, 3.6 km race with slope (≈8%, and indirect VO2max measurement. CV was determined from the linear relationship between distance and run time on the first two tests. The subjects then took part in two official 10 km and 21.1 km (half marathon races. VVO2max was calculated from the VO2max through a metabolic equation. VO2max showed the best association with running performance in the 10 and 21.1 km events. For the uphill race, VVO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.91±0.07, followed by VVO2max (0.90±0.04 and VC (0.87±0.06. This study showed strong associations between physiological variables established by low-cost, user-friendly indirect methods and running performance in the 10 and 21.1 km (flatland and 3.6 km (uphill running events.

Separation and estimation of muscle spindle and tension receptor populations by vibration of the biceps muscle in the frog.

Science.gov (United States)

Giszter, S F; Kargo, W J

2002-10-01

Frog spinal cord reflex behaviors have been used to test the idea of spinal primitives. We have suggested a significant role for proprioception in regulation of primitives. However the in vivo behavior of spindle and golgi tendon receptors in frogs in response to vibration are not well described and the proportions of these proprioceptors are not established. In this study, we examine the selectivity of muscle vibration in the spinal frog. The aim of the study was (1) to examine how hindlimb muscle spindles and GTO receptors are activated by muscle vibration and (2) to estimate the relative numbers of GTO receptors and spindle afferents in a selected muscle, for comparison with the mammal. Single muscle afferents from the biceps muscle were identified in the dorsal roots. These were tested in response to biceps vibration, intramuscular stimulation and biceps nerve stimulation. Biceps units were categorized into two types: First, spindle afferents which had a high conduction velocity (approximately 20-30 m/s), responded reliably (were entrained 1:1) to muscle vibration, and exhibited distinct pauses to shortening muscle contractions. Second, golgi tendon organ afferents, which had a lower conduction velocity (approximately 10-20 m/s), responded less reliably to muscle vibration at physiologic muscle lengths, but responded more reliably at extended lengths or with background muscle contraction, and exhibited distinct bursts to shortening muscle contractions. Vibration responses of these units were tested with and without muscle curarization. Ensemble (suction electrode) recordings from the dorsal roots were used to provide rough estimates of the proportions of the two muscle afferent types.

O pensamento de Max Weber

Directory of Open Access Journals (Sweden)

Maurício Tragtenberg

1966-06-01

Full Text Available Max Weber inicia sua carreira universitária em 1893, como professor extraordinário de Direito Mercantil e Romano, na Universidade de Berlim. Em 1894 assume a Cadeira de Economia Política na Universidade de Hamburgo e em 1897 leciona na Universidade de Heidelberg.

Improved lithium-ion battery anode capacity with a network of easily fabricated spindle-like carbon nanofibers.

Science.gov (United States)

Liu, Mengting; Xie, Wenhe; Gu, Lili; Qin, Tianfeng; Hou, Xiaoyi; He, Deyan

2016-01-01

A novel network of spindle-like carbon nanofibers was fabricated via a simplified synthesis involving electrospinning followed by preoxidation in air and postcarbonization in Ar. Not only was the as-obtained carbon network comprised of beads of spindle-like nanofibers but the cubic MnO phase and N elements were successfully anchored into the amorphous carbon matrix. When directly used as a binder-free anode for lithium-ion batteries, the network showed excellent electrochemical performance with high capacity, good rate capacity and reliable cycling stability. Under a current density of 0.2 A g -1 , it delivered a high reversible capacity of 875.5 mAh g -1 after 200 cycles and 1005.5 mAh g -1 after 250 cycles with a significant coulombic efficiency of 99.5%.

Optimal resampling for the noisy OneMax problem

OpenAIRE

Liu, Jialin; Fairbank, Michael; Pérez-Liébana, Diego; Lucas, Simon M.

2016-01-01

The OneMax problem is a standard benchmark optimisation problem for a binary search space. Recent work on applying a Bandit-Based Random Mutation Hill-Climbing algorithm to the noisy OneMax Problem showed that it is important to choose a good value for the resampling number to make a careful trade off between taking more samples in order to reduce noise, and taking fewer samples to reduce the total computational cost. This paper extends that observation, by deriving an analytical expression f...

Functional importance of the anaphase-promoting complex-Cdh1-mediated degradation of TMAP/CKAP2 in regulation of spindle function and cytokinesis.

Science.gov (United States)

Hong, Kyung Uk; Park, Young Soo; Seong, Yeon-Sun; Kang, Dongmin; Bae, Chang-Dae; Park, Joobae

2007-05-01

Cytoskeleton-associated protein 2 (CKAP2), also known as tumor-associated microtubule-associated protein (TMAP), is a novel microtubule-associated protein that is frequently upregulated in various malignances. However, its cellular functions remain unknown. A previous study has shown that its protein level begins to increase during G(1)/S and peaks at G(2)/M, after which it decreases abruptly. Ectopic overexpression of TMAP/CKAP2 induced microtubule bundling related to increased microtubule stability. TMAP/CKAP2 overexpression also resulted in cell cycle arrest during mitosis due to a defect in centrosome separation and subsequent formation of a monopolar spindle. We also show that degradation of TMAP/CKAP2 during mitotic exit is mediated by the anaphase-promoting complex bound to Cdh1 and that the KEN box motif near the N terminus is necessary for its destruction. Compared to the wild type, expression of a nondegradable mutant of TMAP/CKAP2 significantly increased the occurrence of spindle defects and cytokinesis failure. These results suggest that TMAP/CKAP2 plays a role in the assembly and maintenance of mitotic spindles, presumably by regulating microtubule dynamics, and its destruction during mitotic exit serves an important role in the completion of cytokinesis and in the maintenance of spindle bipolarity in the next mitosis.

Max Reinhardt Haus Berliini / Triin Ojari

Index Scriptorium Estoniae

Ojari, Triin, 1974-

1998-01-01

Arhitekt Peter Eisenmani projekteeritud multifunktsionaalne maja on planeeritud II maailmasõjas hävinud Max Reinhardti teatrihoone kohale. Ühte hoonetahukasse kui uude maamärki on 'volditud' kokku aktiivse linnaelu kõik aspektid.

In-silico modeling of the mitotic spindle assembly checkpoint.

Directory of Open Access Journals (Sweden)

Bashar Ibrahim

2008-02-01

Full Text Available The Mitotic Spindle Assembly Checkpoint ((MSAC is an evolutionary conserved mechanism that ensures the correct segregation of chromosomes by restraining cell cycle progression from entering anaphase until all chromosomes have made proper bipolar attachments to the mitotic spindle. Its malfunction can lead to cancer.We have constructed and validated for the human (MSAC mechanism an in silico dynamical model, integrating 11 proteins and complexes. The model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. Originating from the biochemical reactions for the underlying molecular processes, non-linear ordinary differential equations for the concentrations of 11 proteins and complexes of the (MSAC are derived. Most of the kinetic constants are taken from literature, the remaining four unknown parameters are derived by an evolutionary optimization procedure for an objective function describing the dynamics of the APC:Cdc20 complex. MCC:APC dissociation is described by two alternatives, namely the "Dissociation" and the "Convey" model variants. The attachment of the kinetochore to microtubuli is simulated by a switching parameter silencing those reactions which are stopped by the attachment. For both, the Dissociation and the Convey variants, we compare two different scenarios concerning the microtubule attachment dependent control of the dissociation reaction. Our model is validated by simulation of ten perturbation experiments.Only in the controlled case, our models show (MSAC behaviour at meta- to anaphase transition in agreement with experimental observations. Our simulations revealed that for (MSAC activation, Cdc20 is not fully sequestered; instead APC is inhibited by MCC binding.

Beyond NextGen: AutoMax Overview and Update

Science.gov (United States)

Kopardekar, Parimal; Alexandrov, Natalia

2013-01-01

Main Message: National and Global Needs - Develop scalable airspace operations management system to accommodate increased mobility needs, emerging airspace uses, mix, future demand. Be affordable and economically viable. Sense of Urgency. Saturation (delays), emerging airspace uses, proactive development. Autonomy is Needed for Airspace Operations to Meet Future Needs. Costs, time critical decisions, mobility, scalability, limits of cognitive workload. AutoMax to Accommodate National and Global Needs. Auto: Automation, autonomy, autonomicity for airspace operations. Max: Maximizing performance of the National Airspace System. Interesting Challenges and Path Forward.

THE SPINDLE: AN IRRADIATED DISK AND BENT PROTOSTELLAR JET IN ORION

Energy Technology Data Exchange (ETDEWEB)

Bally, John; Youngblood, Allison; Ginsburg, Adam, E-mail: John.Bally@colorado.edu, E-mail: Allison.Youngblood@colorado.edu, E-mail: Adam.Ginsburg@colorado.edu [Department of Astrophysical and Planetary Sciences, University of Colorado, UCB 389, Boulder, CO 80309 (United States)

2012-09-10

We present Hubble Space Telescope observations of a bent, pulsed Herbig-Haro jet, HH 1064, emerging from the young star Parenago 2042 embedded in the H II region NGC 1977 located about 30' north of the Orion Nebula. This outflow contains eight bow shocks in the redshifted western lobe and five bow shocks in the blueshifted eastern lobe. Shocks within a few thousand AU of the source star exhibit proper motions of {approx}160 km s{sup -1} but motions decrease with increasing distance. Parenago 2042 is embedded in a proplyd-a photoevaporating protoplanetary disk. A remarkable set of H{alpha} arcs resembling a spindle surround the redshifted (western) jet. The largest arc with a radius of 500 AU may trace the ionized edge of a circumstellar disk inclined by {approx}30 Degree-Sign . The spindle may be the photoionized edge of either a {approx}3 km s{sup -1} FUV-driven wind from the outer disk or a faster MHD-powered flow from an inner disk. The HH 1064 jet appears to be deflected north by photoablation of the south-facing side of a mostly neutral jet beam. V2412 Ori, located 1' west of Parenago 2042 drives a second bent flow, HH 1065. Both HH 1064 and 1065 are surrounded by LL Ori-type bows marking the boundary between the outflow cavity and the surrounding nebula.

Study of Contactless Power Supply for Spindle Ultrasonic Vibrator

Science.gov (United States)

Chen, T. R.; Lee, Y. L.; Liu, H. T.; Chen, S. M.; Chang, H. Z.

2017-11-01

In this study, a contactless power supply for the ultrasonic motor on the spindle is proposed. The proposed power supply is composed of a series-parallel resonant circuit and a cylindrical contactless transformer. Based on the study and rotation experiments, it can be seen that the proposed power supply can both provide a stable ac power with 25 kHz / 70 V to the ultrasonic motor. When the output power is 250 W, the efficiency of the proposed supply is 89.8 % in respectively rotation tests. When the output power is more than 150 W, the efficiency of the proposed supply is higher than 80 % within the rated output power range.

An approach to get thermodynamic properties from speed of sound

International Nuclear Information System (INIS)

Núñez, M A; Medina, L A

2017-01-01

An approach for estimating thermodynamic properties of gases from the speed of sound u, is proposed. The square u 2 , the compression factor Z and the molar heat capacity at constant volume C V are connected by two coupled nonlinear partial differential equations. Previous approaches to solving this system differ in the conditions used on the range of temperature values [T min ,T max ]. In this work we propose the use of Dirichlet boundary conditions at T min , T max . The virial series of the compression factor Z = 1+Bρ+Cρ 2 +… and other properties leads the problem to the solution of a recursive set of linear ordinary differential equations for the B, C. Analytic solutions of the B equation for Argon are used to study the stability of our approach and previous ones under perturbation errors of the input data. The results show that the approach yields B with a relative error bounded basically by that of the boundary values and the error of other approaches can be some orders of magnitude lager. (paper)

Elastic and Mechanical Properties of the MAX Phases

Science.gov (United States)

Barsoum, Michel W.; Radovic, Miladin

2011-08-01

The more than 60 ternary carbides and nitrides, with the general formula Mn+1AXn—where n = 1, 2, or 3; M is an early transition metal; A is an A-group element (a subset of groups 13-16); and X is C and/or N—represent a new class of layered solids, where Mn+1Xn layers are interleaved with pure A-group element layers. The growing interest in the Mn+1AXn phases lies in their unusual, and sometimes unique, set of properties that can be traced back to their layered nature and the fact that basal dislocations multiply and are mobile at room temperature. Because of their chemical and structural similarities, the MAX phases and their corresponding MX phases share many physical and chemical properties. In this paper we review our current understanding of the elastic and mechanical properties of bulk MAX phases where they differ significantly from their MX counterparts. Elastically the MAX phases are in general quite stiff and elastically isotropic. The MAX phases are relatively soft (2-8 GPa), are most readily machinable, and are damage tolerant. Some of them are also lightweight and resistant to thermal shock, oxidation, fatigue, and creep. In addition, they behave as nonlinear elastic solids, dissipating 25% of the mechanical energy during compressive cycling loading of up to 1 GPa at room temperature. At higher temperatures, they undergo a brittle-to-plastic transition, and their mechanical behavior is a strong function of deformation rate.

PLK1 regulates spindle formation kinetics and APC/C activation in mouse zygote

Czech Academy of Sciences Publication Activity Database

Baran, V.; Brzáková, Adéla; Rehák, P.; Kovaříková, V.; Šolc, Petr

2016-01-01

Roč. 24, č. 3 (2016), s. 338-345 ISSN 0967-1994 R&D Projects: GA MŠk ED2.1.00/03.0124; GA MŠk LH12057 Institutional support: RVO:67985904 Keywords : APC/C * BI2536 * live cell imaging * mouse zygote * PLK1 * securin * spindle assembly Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.053, year: 2016

Microspectroscopy At Beamline 73 MAX-lab

International Nuclear Information System (INIS)

Engdahl, Anders

2010-01-01

Presentation of some projects at the infrared microspectroscopy experimental station at beamline 73 MAX-lab. Among the subjects are found identification of organic residues in fossil material and examination of the chemistry in an old oak wood wreck.

Germline-specific MATH-BTB substrate adaptor MAB1 regulates spindle length and nuclei identity in maize.

Science.gov (United States)

Juranič, Martina; Srilunchang, Kanok-orn; Krohn, Nádia Graciele; Leljak-Levanic, Dunja; Sprunck, Stefanie; Dresselhaus, Thomas

2012-12-01

Germline and early embryo development constitute ideal model systems to study the establishment of polarity, cell identity, and asymmetric cell divisions (ACDs) in plants. We describe here the function of the MATH-BTB domain protein MAB1 that is exclusively expressed in the germ lineages and the zygote of maize (Zea mays). mab1 (RNA interference [RNAi]) mutant plants display chromosome segregation defects and short spindles during meiosis that cause insufficient separation and migration of nuclei. After the meiosis-to-mitosis transition, two attached nuclei of similar identity are formed in mab1 (RNAi) mutants leading to an arrest of further germline development. Transient expression studies of MAB1 in tobacco (Nicotiana tabacum) Bright Yellow-2 cells revealed a cell cycle-dependent nuclear localization pattern but no direct colocalization with the spindle apparatus. MAB1 is able to form homodimers and interacts with the E3 ubiquitin ligase component Cullin 3a (CUL3a) in the cytoplasm, likely as a substrate-specific adapter protein. The microtubule-severing subunit p60 of katanin was identified as a candidate substrate for MAB1, suggesting that MAB1 resembles the animal key ACD regulator Maternal Effect Lethal 26 (MEL-26). In summary, our findings provide further evidence for the importance of posttranslational regulation for asymmetric divisions and germline progression in plants and identified an unstable key protein that seems to be involved in regulating the stability of a spindle apparatus regulator(s).

Sequence-specific DNA binding by MYC/MAX to low-affinity non-E-box motifs.

Directory of Open Access Journals (Sweden)

Michael Allevato

Full Text Available The MYC oncoprotein regulates transcription of a large fraction of the genome as an obligatory heterodimer with the transcription factor MAX. The MYC:MAX heterodimer and MAX:MAX homodimer (hereafter MYC/MAX bind Enhancer box (E-box DNA elements (CANNTG and have the greatest affinity for the canonical MYC E-box (CME CACGTG. However, MYC:MAX also recognizes E-box variants and was reported to bind DNA in a "non-specific" fashion in vitro and in vivo. Here, in order to identify potential additional non-canonical binding sites for MYC/MAX, we employed high throughput in vitro protein-binding microarrays, along with electrophoretic mobility-shift assays and bioinformatic analyses of MYC-bound genomic loci in vivo. We identified all hexameric motifs preferentially bound by MYC/MAX in vitro, which include the low-affinity non-E-box sequence AACGTT, and found that the vast majority (87% of MYC-bound genomic sites in a human B cell line contain at least one of the top 21 motifs bound by MYC:MAX in vitro. We further show that high MYC/MAX concentrations are needed for specific binding to the low-affinity sequence AACGTT in vitro and that elevated MYC levels in vivo more markedly increase the occupancy of AACGTT sites relative to CME sites, especially at distal intergenic and intragenic loci. Hence, MYC binds diverse DNA motifs with a broad range of affinities in a sequence-specific and dose-dependent manner, suggesting that MYC overexpression has more selective effects on the tumor transcriptome than previously thought.

WiMAX technology and network evolution

CERN Document Server

Etemad, Kamran

2010-01-01

WiMAX, the Worldwide Interoperability for Microwave Access, represents a paradigm shift in telecommunications technology. It offers the promise of cheaper, smaller, and simpler technology compared to existing broadband options such as DSL, cable, fiber, and 3G wireless.

Nanostructured plasma etched, magnetron sputtered nanolaminar Cr2AlC MAX phase thin films

International Nuclear Information System (INIS)

Grieseler, Rolf; Hähnlein, Bernd; Stubenrauch, Mike; Kups, Thomas; Wilke, Marcus; Hopfeld, Marcus; Pezoldt, Jörg; Schaaf, Peter

2014-01-01

The knowledge of the mechanical properties of new materials determines essentially their usability and functionality when used in micro- and nanostructures. MAX phases are new and highly interesting materials due to their unique combination of materials properties. In this article a new method for producing the Cr 2 AlC MAX phase is presented. Thin film elemental multilayer deposition and subsequent rapid thermal annealing forms the MAX phase within seconds. Additionally, free standing microstructures (beams and cantilevers) based on this MAX phase films are prepared by plasma etching. The mechanical properties of these MAX phase microstructures are investigated

Max Jakobson : Vene ohtu täna veel pole / Max Jakobson ; interv. Vallo Toomet, Urmet Kook, Kaarel Tarand

Index Scriptorium Estoniae

Jakobson, Max, 1923-2013

2003-01-01

Balti riikide NATOga liitumise mõjust julgeolekule Läänemere regioonis, Euroopa Liidu kaitsepoliitikast ning Venemaa ja islamiterrorismi ohust julgeolekule. Vt. samas: Toomas Hiio ülevaade Max Jakobsoni elust ja tegevusest

Functional Importance of the Anaphase-Promoting Complex-Cdh1-Mediated Degradation of TMAP/CKAP2 in Regulation of Spindle Function and Cytokinesis▿ †

Science.gov (United States)

Hong, Kyung Uk; Park, Young Soo; Seong, Yeon-Sun; Kang, Dongmin; Bae, Chang-Dae; Park, Joobae

2007-01-01

Cytoskeleton-associated protein 2 (CKAP2), also known as tumor-associated microtubule-associated protein (TMAP), is a novel microtubule-associated protein that is frequently upregulated in various malignances. However, its cellular functions remain unknown. A previous study has shown that its protein level begins to increase during G1/S and peaks at G2/M, after which it decreases abruptly. Ectopic overexpression of TMAP/CKAP2 induced microtubule bundling related to increased microtubule stability. TMAP/CKAP2 overexpression also resulted in cell cycle arrest during mitosis due to a defect in centrosome separation and subsequent formation of a monopolar spindle. We also show that degradation of TMAP/CKAP2 during mitotic exit is mediated by the anaphase-promoting complex bound to Cdh1 and that the KEN box motif near the N terminus is necessary for its destruction. Compared to the wild type, expression of a nondegradable mutant of TMAP/CKAP2 significantly increased the occurrence of spindle defects and cytokinesis failure. These results suggest that TMAP/CKAP2 plays a role in the assembly and maintenance of mitotic spindles, presumably by regulating microtubule dynamics, and its destruction during mitotic exit serves an important role in the completion of cytokinesis and in the maintenance of spindle bipolarity in the next mitosis. PMID:17339342

Torque-Controlled Adaptive Speed Control on a CNC Marble Saw Machine

Directory of Open Access Journals (Sweden)

Ugur Simsir

2015-02-01

Full Text Available Although CNC marble saw machines can automatically cut marble slabs to desired dimensions, saw speed and feed rate are selected by operator according to stone parameters, features of the saw, and its immersion depth. If the feed rate is selected lower than the optimal value, there will be time-loss and capacity deficiencies or if it is selected faster, cutting quality will decrease, spindle motor will draw more current, and saw blade will corrode faster. While cutting especially thick materials, saw may be stacked in the stone, cutting quality may be impaired, saw blade may be abraded earlier, precision quality may go down because of increase in measurement errors, and machine may be damaged with the increase in vibrations when improper feed rates are selected. Because of nonhomogeneity of the slabs and deterioration of the saw blade, operator cannot determine a persistent feed rate. This study is targeted to find saw speeds according to saw diameter and optimum feed rate by means of limiting vibrations and current drawn from saw motor and torque accordingly in order to increase working performance of CNC marble saw machines. Thanks to adaptive adjustment of feed rate, one can save on material as well as time, labour, and cost by making use of optimum energy.

LTE, WiMAX and WLAN network design, optimization and performance analysis

CERN Document Server

Korowajczuk, Leonhard

2011-01-01

A technological overview of LTE and WiMAX LTE, WiMAX and WLAN Network Design, Optimization and Performance Analysis provides a practical guide to LTE and WiMAX technologies introducing various tools and concepts used within. In addition, topics such as traffic modelling of IP-centric networks, RF propagation, fading, mobility, and indoor coverage are explored; new techniques which increase throughput such as MIMO and AAS technology are highlighted; and simulation, network design and performance analysis are also examined. Finally, in the latter part of the book Korowajczuk gives a step-by-step

Toughening Mechanisms in Nanolayered MAX Phase Ceramics—A Review

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Xinhua Chen

2017-03-01

Full Text Available Advanced engineering and functional ceramics are sensitive to damage cracks, which delay the wide applications of these materials in various fields. Ceramic composites with enhanced fracture toughness may trigger a paradigm for design and application of the brittle components. This paper reviews the toughening mechanisms for the nanolayered MAX phase ceramics. The main toughening mechanisms for these ternary compounds were controlled by particle toughening, phase-transformation toughening and fiber-reinforced toughening, as well as texture toughening. Based on the various toughening mechanisms in MAX phase, models of SiC particles and fibers toughening Ti3SiC2 are established to predict and explain the toughening mechanisms. The modeling work provides insights and guidance to fabricate MAX phase-related composites with optimized microstructures in order to achieve the desired mechanical properties required for harsh application environments.

The development of a differential game related to terrorism: Min-Max differential game

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Abd El-Monem A. Megahed

2017-07-01

Full Text Available In this work, we study a differential game related to terrorism: Min-Max differential game taking into account the governmental activities such as the education quality, increasing the chances of labor, social justice, religious awareness and security arrangements. A Min-Max differential game between government and terrorist organizations is considered in this study. To obtain the optimal strategy of solving this problem, we study the analytic form of a Min-Max differential game and the governmental activities. Furthermore, a saddle point of a Min-Max differential game is studied.

Mucinous tubular and spindle cell carcinoma of kidney: A clinicopathologic study of six cases

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Mudassar Hussain

2012-01-01

Full Text Available Background: Mucinous tubular and spindle carcinoma (MTSCC of kidney is a rare, low-grade polymorphic tumor. Recent studies have described a wide morphology spectrum of this tumor. Aim: To report the clinico-pathologic features of six cases of MTSCC of kidney. Materials and Methods: Six cases of MTSCC of kidney were studied and literature was reviewed. Immunohistochemistry was done by Envision method. Results: The age of the patients ranged from 44 to 84 years (mean 58.5 years. Four patients were males and two were females. The tumor was located in the left kidney in four cases and in the right kidney in two cases. The tumor size ranged from 4.5 to 15 cm (mean 6.4 cm. All tumors exhibited an admixture of tubules, spindle cells, and mucinous stroma in variable proportions. Tubules were predominant in five cases and spindle cells in one case. Psammomatous calcifications, papillations, and necrosis were seen in two cases. Collections of foamy histiocytes were noted in four cases. Cytoplasmic vacuoles and osseous metaplasia were seen in one case each. All cases were Fuhrman′s nuclear grade II. Five cases were of stage pT1, and one was pT3. All cases stained positive for alcian blue at pH 2.5. Immunohistochemical stain CK7 was positive in all cases and CD10 was positive in 1/1 case. All patients were alive and well at follow-up of 12-59 months (mean 33.5 months. No metastases were detected. Conclusions: We report six cases of MTSCC of kidney, a rare distinct variant of RCC, with a favorable prognosis. A male predominance was seen in our cases. MTSCC shares histologic and immunohistochemical overlap with papillary renal cell carcinoma (PRCC and cytogenetic analysis should be performed in difficult cases to avoid a misdiagnosis.

Neural mechanisms of mental schema: a triplet of delta, low beta/spindle and ripple oscillations.

Science.gov (United States)

Ohki, Takefumi; Takei, Yuichi

2018-02-06

Schemas are higher-level knowledge structures that integrate and organise lower-level representations. As internal templates, schemas are formed according to how events are perceived, interpreted and remembered. Although these higher-level units are assumed to play a fundamental role in our daily life from an early age, the neuronal basis and mechanisms of schema formation and use remain largely unknown. It is important to elucidate how the brain constructs and maintains these higher-level units. In order to examine the possible neural underpinnings of schema, we recapitulate previous work and discuss their findings related to schemas as the brain template. We specifically focused on low beta/spindle oscillations, which are assumed to be the key components of schemas, and propose that the brain template is implemented with a triplet of neural oscillations, that is delta, low beta/spindle and ripple oscillations. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Multi-response parametric optimization in drilling of bamboo/Kevlar fiber reinforced sandwich composite

Science.gov (United States)

Singh, Thingujam Jackson; Samanta, Sutanu

2016-09-01

In the present work an attempt was made towards parametric optimization of drilling bamboo/Kevlar K29 fiber reinforced sandwich composite to minimize the delamination occurred during the drilling process and also to maximize the tensile strength of the drilled composite. The spindle speed and the feed rate of the drilling operation are taken as the input parameters. The influence of these parameters on delamination and tensile strength of the drilled composite studied and analysed using Taguchi GRA and ANOVA technique. The results show that both the response parameters i.e. delamination and tensile strength are more influenced by feed rate than spindle speed. The percentage contribution of feed rate and spindle speed on response parameters are 13.88% and 81.74% respectively.

Epistatic determinism of durum wheat resistance to the wheat spindle streak mosaic virus.

Science.gov (United States)

Holtz, Yan; Bonnefoy, Michel; Viader, Véronique; Ardisson, Morgane; Rode, Nicolas O; Poux, Gérard; Roumet, Pierre; Marie-Jeanne, Véronique; Ranwez, Vincent; Santoni, Sylvain; Gouache, David; David, Jacques L

2017-07-01

The resistance of durum wheat to the Wheat spindle streak mosaic virus (WSSMV) is controlled by two main QTLs on chromosomes 7A and 7B, with a huge epistatic effect. Wheat spindle streak mosaic virus (WSSMV) is a major disease of durum wheat in Europe and North America. Breeding WSSMV-resistant cultivars is currently the only way to control the virus since no treatment is available. This paper reports studies of the inheritance of WSSMV resistance using two related durum wheat populations obtained by crossing two elite cultivars with a WSSMV-resistant emmer cultivar. In 2012 and 2015, 354 recombinant inbred lines (RIL) were phenotyped using visual notations, ELISA and qPCR and genotyped using locus targeted capture and sequencing. This allowed us to build a consensus genetic map of 8568 markers and identify three chromosomal regions involved in WSSMV resistance. Two major regions (located on chromosomes 7A and 7B) jointly explain, on the basis of epistatic interactions, up to 43% of the phenotypic variation. Flanking sequences of our genetic markers are provided to facilitate future marker-assisted selection of WSSMV-resistant cultivars.

Phosphorylation of CPAP by Aurora-A Maintains Spindle Pole Integrity during Mitosis

OpenAIRE

En-Ju Chou; Liang-Yi Hung; Chieh-Ju C. Tang; Wen-Bin Hsu; Hsin-Yi Wu; Pao-Chi Liao; Tang K. Tang

2016-01-01

CPAP is required for centriole elongation during S/G2 phase, but the role of CPAP in mitosis is incompletely understood. Here, we show that CPAP maintains spindle pole integrity through its phosphorylation by Aurora-A during mitosis. Depletion of CPAP induced a prolonged delay in mitosis, pericentriolar material (PCM) dispersion, and multiple mitotic abnormalities. Further studies demonstrated that CPAP directly interacts with and is phosphorylated by Aurora-A at serine 467 during mitosis. In...

maxAlike

DEFF Research Database (Denmark)

Menzel, Karl Peter; Stadler, Peter F.; Gorodkin, Jan

2011-01-01

MOTIVATION: The task of reconstructing a genomic sequence from a particular species is gaining more and more importance in the light of the rapid development of high-throughput sequencing technologies and their limitations. Applications include not only compensation for missing data in unsequenced...... genomic regions and the design of oligonucleotide primers for target genes in species with lacking sequence information but also the preparation of customized queries for homology searches. RESULTS: We introduce the maxAlike algorithm, which reconstructs a genomic sequence for a specific taxon based...... on sequence homologs in other species. The input is a multiple sequence alignment and a phylogenetic tree that also contains the target species. For this target species, the algorithm computes nucleotide probabilities at each sequence position. Consensus sequences are then reconstructed based on a certain...

Downregulation of Protein 4.1R impairs centrosome function,bipolar spindle organization and anaphase

Energy Technology Data Exchange (ETDEWEB)

Spence, Jeffrey R.; Go, Minjoung M.; Bahmanyar, S.; Barth,A.I.M.; Krauss, Sharon Wald

2006-03-17

Centrosomes nucleate and organize interphase MTs and areinstrumental in the assembly of the mitotic bipolar spindle. Here wereport that two members of the multifunctional protein 4.1 family havedistinct distributions at centrosomes. Protein 4.1R localizes to maturecentrioles whereas 4.1G is a component of the pericentriolar matrixsurrounding centrioles. To selectively probe 4.1R function, we used RNAinterference-mediated depletion of 4.1R without decreasing 4.1Gexpression. 4.1R downregulation reduces MT anchoring and organization atinterphase and impairs centrosome separation during prometaphase.Metaphase chromosomes fail to properly condense/align and spindleorganization is aberrant. Notably 4.1R depletion causes mislocalizationof its binding partner NuMA (Nuclear Mitotic Apparatus Protein),essential for spindle pole focusing, and disrupts ninein. Duringanaphase/telophase, 4.1R-depleted cells have lagging chromosomes andaberrant MT bridges. Our data provide functional evidence that 4.1R makescrucial contributions to centrosome integrity and to mitotic spindlestructure enabling mitosis and anaphase to proceed with the coordinatedprecision required to avoid pathological events.

Penultimate modeling of spatial extremes: statistical inference for max-infinitely divisible processes

KAUST Repository

Huser, Raphaël

2018-01-09

Extreme-value theory for stochastic processes has motivated the statistical use of max-stable models for spatial extremes. However, fitting such asymptotic models to maxima observed over finite blocks is problematic when the asymptotic stability of the dependence does not prevail in finite samples. This issue is particularly serious when data are asymptotically independent, such that the dependence strength weakens and eventually vanishes as events become more extreme. We here aim to provide flexible sub-asymptotic models for spatially indexed block maxima, which more realistically account for discrepancies between data and asymptotic theory. We develop models pertaining to the wider class of max-infinitely divisible processes, extending the class of max-stable processes while retaining dependence properties that are natural for maxima: max-id models are positively associated, and they yield a self-consistent family of models for block maxima defined over any time unit. We propose two parametric construction principles for max-id models, emphasizing a point process-based generalized spectral representation, that allows for asymptotic independence while keeping the max-stable extremal-$t$ model as a special case. Parameter estimation is efficiently performed by pairwise likelihood, and we illustrate our new modeling framework with an application to Dutch wind gust maxima calculated over different time units.

Augmentative Device Helps Max Speak. PACER Center ACTion Information Sheets. PHP-c75

Science.gov (United States)

PACER Center, 2014

2014-01-01

This Action Information Sheet follows a family's process of selecting and using augmentative and alternative communication to help their young son, Max, speak. Max is affected by global dyspraxia, which makes learning new motor skills--especially speech--quite difficult. For the first years of his life, Max could not say words. Before he and his…

Pacemaker activity in a sensory ending with multiple encoding sites : The cat muscle spindle primary ending

NARCIS (Netherlands)

Banks, RW; Hulliger, M; Scheepstra, KA; Otten, E

1997-01-01

1. A combined physiological, histological and computer modelling study was carried out on muscle spindles of the cat tenuissimus muscle to examine whether there was any correlation between the functional interaction of putative encoding sites, operated separately by static and dynamic fusimotor

Multiple variables explain the variability in the decrement in VO2max during acute hypobaric hypoxia.

Science.gov (United States)

Robergs, R A; Quintana, R; Parker, D L; Frankel, C C

1998-06-01

We used multiple regression analyses to determine the relationships between the decrement in sea level (SL, 760 Torr) VO2max during hypobaric hypoxia (HH) and variables that could alter or be related to the decrement in VO2max. HH conditions consisted of 682 Torr, 632 Torr, and 566 Torr, and the measured independent variables were SL-VO2max, SL lactate threshold (SL-LT), the change in hemoglobin saturation at VO2max between 760 and 566 Torr (delta SaO2max), lean body mass (LBM), and gender. Male (N = 14) and female (N = 14) subjects of varied fitness, training status, and residential altitude (1,640-2,460 m) completed cycle ergometry tests of VO2max at each HH condition under randomized and single-blinded conditions. VO2max decreased significantly from 760 Torr after 682 Torr (approximately 915 m) (3.5 +/- 0.9 to 3.4 +/- 0.8 L.min-1, P = 0.0003). Across all HH conditions, the slope of the relative decrement in VO2max (%VO2max) during HH was -9.2%/100 mm Hg (-8.1%/1000 m) with an initial decrease from 100% estimated to occur below 705 Torr (610 m). Step-wise multiple regression revealed that SL-VO2max, SL-LT, delta SaO2max, LBM, and gender each significantly combined to account for 89.03% of the variance in the decrement in VO2max (760-566 Torr) (P decrement in VO2max during HH. The unique variance explanation afforded by SL-LT, LBM, and gender suggests that issues pertaining to oxygen diffusion within skeletal muscle may add to the explanation of between subjects variability in the decrement in VO2max during HH.

Eight-component retrievals from ground-based MAX-DOAS observations

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H. Irie

2011-06-01

Full Text Available We attempt for the first time to retrieve lower-tropospheric vertical profile information for 8 quantities from ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS observations. The components retrieved are the aerosol extinction coefficients at two wavelengths, 357 and 476 nm, and NO₂, HCHO, CHOCHO, H₂O, SO₂, and O₃ volume mixing ratios. A Japanese MAX-DOAS profile retrieval algorithm, version 1 (JM1, is applied to observations performed at Cabauw, the Netherlands (51.97° N, 4.93° E, in June–July 2009 during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI. Of the retrieved profiles, we focus here on the lowest-layer data (mean values at altitudes 0–1 km, where the sensitivity is usually highest owing to the longest light path. In support of the capability of the multi-component retrievals, we find reasonable overall agreement with independent data sets, including a regional chemical transport model (CHIMERE and in situ observations performed near the surface (2–3 m and at the 200-m height level of the tall tower in Cabauw. Plumes of enhanced HCHO and SO₂ were likely affected by biogenic and ship emissions, respectively, and an improvement in their emission strengths is suggested for better agreement between CHIMERE simulations and MAX-DOAS observations. Analysis of air mass factors indicates that the horizontal spatial representativeness of MAX-DOAS observations is about 3–15 km (depending mainly on aerosol extinction, comparable to or better than the spatial resolution of current UV-visible satellite observations and model calculations. These demonstrate that MAX-DOAS provides multi-component data useful for the evaluation of satellite observations and model calculations and can play an important role in bridging different data sets having different spatial resolutions.

Epidemiologia e geografia: o complexo patogênico de Max. Sorre

OpenAIRE

Ferreira, Marcelo Urbano

1991-01-01

Apresentam-se alguns traços essenciais do conceito de complexo patogênico, formulado pelo geógrafo francês Max. Sorre, com o objetivo de estimular estudos de integração entre a epidemiologia e a geografia.Some essential features of the pathogenic complex concept formulated by the French geographer Max. Sorre are presented, aiming at integrating epidemiological and geografic studies.

V/V(max) test applied to SMM gamma-ray bursts

Science.gov (United States)

Matz, S. M.; Higdon, J. C.; Share, G. H.; Messina, D. C.; Iadicicco, A.

1992-01-01

We have applied the V/V(max) test to candidate gamma-ray bursts detected by the Gamma-Ray Spectrometer (GRS) aboard the SMM satellite to examine quantitatively the uniformity of the burst source population. For a sample of 132 candidate bursts identified in the GRS data by an automated search using a single uniform trigger criterion we find average V/V(max) = 0.40 +/- 0.025. This value is significantly different from 0.5, the average for a uniform distribution in space of the parent population of burst sources; however, the shape of the observed distribution of V/V(max) is unusual and our result conflicts with previous measurements. For these reasons we can currently draw no firm conclusion about the distribution of burst sources.

A Modified MinMax k-Means Algorithm Based on PSO.

Science.gov (United States)

Wang, Xiaoyan; Bai, Yanping

The MinMax k -means algorithm is widely used to tackle the effect of bad initialization by minimizing the maximum intraclustering errors. Two parameters, including the exponent parameter and memory parameter, are involved in the executive process. Since different parameters have different clustering errors, it is crucial to choose appropriate parameters. In the original algorithm, a practical framework is given. Such framework extends the MinMax k -means to automatically adapt the exponent parameter to the data set. It has been believed that if the maximum exponent parameter has been set, then the programme can reach the lowest intraclustering errors. However, our experiments show that this is not always correct. In this paper, we modified the MinMax k -means algorithm by PSO to determine the proper values of parameters which can subject the algorithm to attain the lowest clustering errors. The proposed clustering method is tested on some favorite data sets in several different initial situations and is compared to the k -means algorithm and the original MinMax k -means algorithm. The experimental results indicate that our proposed algorithm can reach the lowest clustering errors automatically.

Multivariate Max-Stable Spatial Processes

KAUST Repository

Genton, Marc G.

2014-01-06

Analysis of spatial extremes is currently based on univariate processes. Max-stable processes allow the spatial dependence of extremes to be modelled and explicitly quantified, they are therefore widely adopted in applications. For a better understanding of extreme events of real processes, such as environmental phenomena, it may be useful to study several spatial variables simultaneously. To this end, we extend some theoretical results and applications of max-stable processes to the multivariate setting to analyze extreme events of several variables observed across space. In particular, we study the maxima of independent replicates of multivariate processes, both in the Gaussian and Student-t cases. Then, we define a Poisson process construction in the multivariate setting and introduce multivariate versions of the Smith Gaussian extremevalue, the Schlather extremal-Gaussian and extremal-t, and the BrownResnick models. Inferential aspects of those models based on composite likelihoods are developed. We present results of various Monte Carlo simulations and of an application to a dataset of summer daily temperature maxima and minima in Oklahoma, U.S.A., highlighting the utility of working with multivariate models in contrast to the univariate case. Based on joint work with Simone Padoan and Huiyan Sang.

Max Planck et les quanta

CERN Document Server

Boudenot, Jean-Claude

2016-01-01

« Les atomes, dit Jean Perrin en 1913, ne sont pas ces éléments éternels et insécables dont l'irréductible simplicité donnait au possible une borne, et, dans leur inimaginable petitesse, nous commençons à pressentir un fourmillement prodigieux de mondes nouveaux ». C'est bien dans un monde totalement nouveau, le monde quantique, que nous a fait pénétrer la découverte des quanta par Max Planck. Son article de 1900 est le déclencheur de l'une des plus grandes révolutions scientifiques de tous les temps. Les trente années qui suivent sont les plus riches de la physique ; Planck, Einstein, Bohr, Sommerfeld, de Broglie, Schrödinger, Heisenberg, Dirac, Born, Pauli… reconstruisent la physique sur de nouvelles bases sur fond de conflit des générations. Le monde est par ailleurs secoué par la guerre, Max Planck est tourmenté et vit des épreuves personnelles dramatiques. C'est l'homme, aussi bien que l'oeuvre, que les auteurs ont tenté de dépeindre dans cet ouvrage. Ils ont également souhait�...

Multivariate Max-Stable Spatial Processes

KAUST Repository

Genton, Marc G.

2014-01-01

Analysis of spatial extremes is currently based on univariate processes. Max-stable processes allow the spatial dependence of extremes to be modelled and explicitly quantified, they are therefore widely adopted in applications. For a better understanding of extreme events of real processes, such as environmental phenomena, it may be useful to study several spatial variables simultaneously. To this end, we extend some theoretical results and applications of max-stable processes to the multivariate setting to analyze extreme events of several variables observed across space. In particular, we study the maxima of independent replicates of multivariate processes, both in the Gaussian and Student-t cases. Then, we define a Poisson process construction in the multivariate setting and introduce multivariate versions of the Smith Gaussian extremevalue, the Schlather extremal-Gaussian and extremal-t, and the BrownResnick models. Inferential aspects of those models based on composite likelihoods are developed. We present results of various Monte Carlo simulations and of an application to a dataset of summer daily temperature maxima and minima in Oklahoma, U.S.A., highlighting the utility of working with multivariate models in contrast to the univariate case. Based on joint work with Simone Padoan and Huiyan Sang.

Germline-Specific MATH-BTB Substrate Adaptor MAB1 Regulates Spindle Length and Nuclei Identity in Maize[W

Science.gov (United States)

Juranić, Martina; Srilunchang, Kanok-orn; Krohn, Nádia Graciele; Leljak-Levanić, Dunja; Sprunck, Stefanie; Dresselhaus, Thomas

2012-01-01

Germline and early embryo development constitute ideal model systems to study the establishment of polarity, cell identity, and asymmetric cell divisions (ACDs) in plants. We describe here the function of the MATH-BTB domain protein MAB1 that is exclusively expressed in the germ lineages and the zygote of maize (Zea mays). mab1 (RNA interference [RNAi]) mutant plants display chromosome segregation defects and short spindles during meiosis that cause insufficient separation and migration of nuclei. After the meiosis-to-mitosis transition, two attached nuclei of similar identity are formed in mab1 (RNAi) mutants leading to an arrest of further germline development. Transient expression studies of MAB1 in tobacco (Nicotiana tabacum) Bright Yellow-2 cells revealed a cell cycle–dependent nuclear localization pattern but no direct colocalization with the spindle apparatus. MAB1 is able to form homodimers and interacts with the E3 ubiquitin ligase component Cullin 3a (CUL3a) in the cytoplasm, likely as a substrate-specific adapter protein. The microtubule-severing subunit p60 of katanin was identified as a candidate substrate for MAB1, suggesting that MAB1 resembles the animal key ACD regulator Maternal Effect Lethal 26 (MEL-26). In summary, our findings provide further evidence for the importance of posttranslational regulation for asymmetric divisions and germline progression in plants and identified an unstable key protein that seems to be involved in regulating the stability of a spindle apparatus regulator(s). PMID:23250449

Dynein Light Intermediate Chain 2 Facilitates the Metaphase to Anaphase Transition by Inactivating the Spindle Assembly Checkpoint.

Directory of Open Access Journals (Sweden)

Sagar P Mahale

Full Text Available The multi-functional molecular motor cytoplasmic dynein performs diverse essential roles during mitosis. The mechanistic importance of the dynein Light Intermediate Chain homologs, LIC1 and LIC2 is unappreciated, especially in the context of mitosis. LIC1 and LIC2 are believed to exist in distinct cytoplasmic dynein complexes as obligate subunits. LIC1 had earlier been reported to be required for metaphase to anaphase progression by inactivating the kinetochore-microtubule attachment-sensing arm of the spindle assembly checkpoint (SAC. However, the functional importance of LIC2 during mitosis remains elusive. Here we report prominent novel roles for the LIC2 subunit of cytoplasmic dynein in regulating the spindle assembly checkpoint. LIC2 depletion in mammalian cells led to prolonged metaphase arrest in the presence of an active SAC and also to stretched kinetochores, thus implicating it in SAC inactivation. Quantitative fluorescence microscopy of SAC components revealed accumulation of both attachment- and tension-sensing checkpoint proteins at metaphase kinetochores upon LIC2 depletion. These observations support a stronger and more diverse role in checkpoint inactivation for LIC2 in comparison to its close homolog LIC1. Our study uncovers a novel functional hierarchy during mitotic checkpoint inactivation between the closely related but homologous LIC subunits of cytoplasmic dynein. These subtle functional distinctions between dynein subpopulations could be exploited to study specific aspects of the spindle assembly checkpoint, which is a key mediator of fidelity in eukaryotic cell division.

Simulation of Vibrations in Real Time Plane Milling with Spindle Speed Correction

Directory of Open Access Journals (Sweden)

I. I. Ivanov

2017-01-01

Full Text Available In milling the hard-to-machine materials vibrations (chatter often arise from the high cutting forces if a technological system is insufficiently rigid.The main way to suppress these vibrations is to increase a stiffness of the mounting system of the tool and the work-piece to be machined. However, sometimes this method doesn’t lead to desirable result because of high values of intrinsic pliability of the tool and the work-piece. Currently, there are more complicated methods to ensure milling process quality. Among them there are three main groups:mathematical simulation of milling process dynamics and computation of processing parameters which provide high quality of machined surface, low level of vibrations and static deflections of a tool and a work-piece;introduction of the active vibration suppression devices into machine tool design; such devices include a vibration sensor, a feedback circuit, and an actuator which induces kinematic or force action on the oscillatory system;control of processing parameters, mainly of rotation frequency for minimizing the amplitudes of vibrations.The paper studies one of the 3rd group methods. There is a suggestion to process a signal of vibrational accelerations in real time and detect a chatter onset. If the chatter has been detected its frequency is to be identified, and the new value of rotation speed is set:where Ω – rotation frequency, rot/s; p – the tool eigenfrequency value identified during processing, Hz; z – mill tooth number; i – positive integer number; ε<1 – small positive parameter. In the current research it is assumed that ε = 0,2.The formula has been chosen because at the rotation frequency axis where tooth pass frequency is slightly less than the eigenfrequency divided by the integer value there are stable zones of dynamics in the milling process.The study shows a developed model of the plane milling dynamics. It includes a dynamic model of the tool, a model of cutting

HEART RATE VARIABILITY AND BODY COMPOSITION AS VO2MAX DETERMINANTS

Directory of Open Access Journals (Sweden)

Henry Humberto León-Ariza

Full Text Available ABSTRACT Introduction: The maximum oxygen consumption (VO2max is the gold standard in the cardiorespiratory endurance assessment. Objective: This study aimed to develop a mathematical model that contains variables to determine the VO2max of sedentary people. Methods: Twenty participants (10 men and 10 women with a mean age of 19.8±1.77 years were included. For each participant, body composition (percentage of fat and muscle, heart rate variability (HRV at rest (supine and standing, and VO2max were evaluated through an indirect test on a cycloergometer. A multivariate linear regression model was developed from the data obtained, and the model assumptions were verified. Results: Using the data obtained, including percentage of fat (F, percentage of muscle (M, percentage of power at very low frequency (VLF, α-value of the detrended fluctuation analysis (DFAα1, heart rate (HR in the resting standing position, and age of the participants, a model was established for men, which was expressed as VO2max = 4.216 + (Age*0.153 + (F*0.110 - (M*0.053 - (VLF*0.649 - (DFAα1*2.441 - (HR*0.014, with R2 = 0.965 and standard error = 0.146 L/min. For women, the model was expressed as VO2max = 1.947 - (Age*0.047 + (F*0.024 + (M*0.054 + (VLF*1.949 - (DFAα1*0.424 - (HR*0.019, with R2 = 0.987 and standard error = 0.077 L/min. Conclusion: The obtained model demonstrated the influence exerted by body composition, the autonomic nervous system, and age in the prediction of VO2max.

Epidemiologia e geografia: o complexo patogênico de Max. Sorre

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Marcelo Urbano Ferreira

1991-09-01

Full Text Available Apresentam-se alguns traços essenciais do conceito de complexo patogênico, formulado pelo geógrafo francês Max. Sorre, com o objetivo de estimular estudos de integração entre a epidemiologia e a geografia.Some essential features of the pathogenic complex concept formulated by the French geographer Max. Sorre are presented, aiming at integrating epidemiological and geografic studies.

Effect of speed endurance training and reduced training volume on running economy and single muscle fiber adaptations in trained runners.

Science.gov (United States)

Skovgaard, Casper; Christiansen, Danny; Christensen, Peter M; Almquist, Nicki W; Thomassen, Martin; Bangsbo, Jens

2018-02-01

The aim of the present study was to examine whether improved running economy with a period of speed endurance training and reduced training volume could be related to adaptations in specific muscle fibers. Twenty trained male (n = 14) and female (n = 6) runners (maximum oxygen consumption (VO 2 -max): 56.4 ± 4.6 mL/min/kg) completed a 40-day intervention with 10 sessions of speed endurance training (5-10 × 30-sec maximal running) and a reduced (36%) volume of training. Before and after the intervention, a muscle biopsy was obtained at rest, and an incremental running test to exhaustion was performed. In addition, running at 60% vVO 2 -max, and a 10-km run was performed in a normal and a muscle slow twitch (ST) glycogen-depleted condition. After compared to before the intervention, expression of mitochondrial uncoupling protein 3 (UCP3) was lower (P economy at 60% vVO 2 -max (11.6 ± 0.2 km/h) and at v10-km (13.7 ± 0.3 km/h) was ~2% better (P economy with intense training may be related to changes in expression of proteins linked to energy consuming processes in primarily ST muscle fibers. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Optimization of Cutting Parameters on Delamination of Drilling Glass-Polyester Composites

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Majid Habeeb Faidh-Allah

2018-02-01

Full Text Available This paper attempted to study the effect of cutting parameters (spindle speed and feed rate on delamination phenomena during the drilling glass-polyester composites. Drilling process was done by CNC machine with 10 mm diameter of high-speed steel (HSS drill bit. Taguchi technique with L16 orthogonal layout was used to analyze the effective parameters on delamination factor. The optimal experiment was no. 13 with spindle speed 1273 rpm and feed 0.05 mm/rev with minimum delamination factor 1.28.

Using MaxCompiler for High Level Synthesis of Trigger Algorithms

CERN Document Server

Summers, Sioni Paris; Sanders, P.

2017-01-01

Firmware for FPGA trigger applications at the CMS experiment is conventionally written using hardware description languages such as Verilog and VHDL. MaxCompiler is an alternative, Java based, tool for developing FPGA applications which uses a higher level of abstraction from the hardware than a hardware description language. An implementation of the jet and energy sum algorithms for the CMS Level-1 calorimeter trigger has been written using MaxCompiler to benchmark against the VHDL implementation in terms of accuracy, latency, resource usage, and code size. A Kalman Filter track fitting algorithm has been developed using MaxCompiler for a proposed CMS Level-1 track trigger for the High-Luminosity LHC upgrade. The design achieves a low resource usage, and has a latency of 187.5 ns per iteration.

The effect of repeated periods of speed endurance training on performance, running economy, and muscle adaptations.

Science.gov (United States)

Skovgaard, C; Almquist, N W; Bangsbo, J

2018-02-01

The effect of repeated intense training interventions was investigated in eight trained male runners (maximum oxygen uptake [VO 2 -max]: 59.3±3.2 mL/kg/min, mean±SD) who performed 10 speed endurance training (SET; repeated 30-seconds "all-out" bouts) and 10 aerobic moderate-intensity training sessions during two 40-day periods (P1 and P2) separated by ~80 days of habitual training. Before and after both P1 and P2, subjects completed an incremental test to exhaustion to determine VO 2 -max and a repeated running test at 90% vVO 2 -max to exhaustion (RRT) to determine short-term endurance capacity. In addition, running economy (RE) was measured at 60% vVO 2 -max (11.9±0.5 km/h) and v10-km (14.3±0.9 km/h), a 10-km track-running test was performed, and a biopsy from m. vastus lateralis was collected. 10-km performance and VO 2 -max (mL/min) were the same prior to P1 and P2, whereas RE was better (P<.05) before P2 than before P1. During P1 and P2, 10-km performance (2.9% and 2.3%), VO 2 -max (2.1% and 2.6%), and RE (1.9% and 1.8% at 60% vVO 2 -max; 1.6% and 2.0% at v10-km) improved (P<.05) to the same extent, respectively. Performance in RRT was 20% better (P<.05) after compared to before P2, with no change in P1. No changes in muscle expression of Na + ,K + -ATPase α1, α2 and β1, NHE1, SERCA1 and SERCA2, actin, and CaMKII were found during neither P1 nor P2. Thus, the present study demonstrates that a second period of intense training leads to improved short-term performance and further improved RE, whereas 10-km performance and VO 2 -max improve to the same extent as during the first period. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Primary spindle cell sarcoma of the prostate and 18 F-fluorodeoxyglucose-positron-emission tomography/computed tomography findings

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Hakan Öztürk

2015-01-01

Conclusion: Spindle sarcomas of the prostate have quite aggressive nature and they have high potential to metastase. Average life expectancy is <1 year and the prognosis is poor. CTx and radiation therapy can′t yield curative effects due to poor differentiation.

Sulfolobus tengchongensis Spindle-Shaped Virus STSV1: Virus-Host Interactions and Genomic Features

DEFF Research Database (Denmark)

Xiang, X.; Chen, L.; Huang, X

2005-01-01

of variable length (68 nm on average) at one end and is the largest of the known spindle-shaped viruses. After infecting its host, the virus multiplied rapidly to high titers (>1010 PFU/ml). Replication of the virus retarded host growth but did not cause lysis of the host cells. STSV1 did not integrate...

Drosophila Polo regulates the spindle assembly checkpoint through Mps1-dependent BubR1 phosphorylation.

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Conde, Carlos; Osswald, Mariana; Barbosa, João; Moutinho-Santos, Tatiana; Pinheiro, Diana; Guimarães, Sofia; Matos, Irina; Maiato, Helder; Sunkel, Claudio E

2013-06-12

Maintenance of genomic stability during eukaryotic cell division relies on the spindle assembly checkpoint (SAC) that prevents mitotic exit until all chromosomes are properly attached to the spindle. Polo is a mitotic kinase proposed to be involved in SAC function, but its role has remained elusive. We demonstrate that Polo and Aurora B functional interdependency comprises a positive feedback loop that promotes Mps1 kinetochore localization and activity. Expression of constitutively active Polo restores normal Mps1 kinetochore levels even after Aurora B inhibition, highlighting a role for Polo in Mps1 recruitment to unattached kinetochores downstream of Aurora B. We also show that Mps1 kinetochore localization is required for BubR1 hyperphosphorylation and formation of the 3F3/2 phosphoepitope. This is essential to allow recruitment of Cdc20 to unattached kinetochores and the assembly of anaphase-promoting complex/cyclosome-inhibitory complexes to levels that ensure long-term SAC activity. We propose a model in which Polo controls Mps1-dependent BubR1 phosphorylation to promote Cdc20 kinetochore recruitment and sustained SAC function.

Dynamic distribution of spindlin in nucleoli, nucleoplasm and spindle from primary oocytes to mature eggs and its critical function for oocyte-to-embryo transition in gibel carp.

Science.gov (United States)

Sun, Min; Li, Zhi; Gui, Jian-Fang

2010-10-01

Spindlin (Spin) was thought as a maternal-effect factor associated with meiotic spindle. Its role for the oocyte-to-embryo transition was suggested in mouse, but its direct evidence for the function had been not obtained in other vertebrates. In this study, we used the CagSpin-specific antibody to investigate CagSpin expression pattern and distribution during oogenesis of gibel carp (Carassius auratus gibelio). First, the oocyte-specific expression pattern and dynamic distribution was revealed in nucleoli, nucleoplasm, and spindle from primary oocytes to mature eggs by immunofluorescence localization. In primary oocytes and growth stage oocytes, CagSpin accumulates in nucleoli in increasing numbers along with the oocyte growth, and its disassembly occurs in vitellogenic oocytes, which implicates that CagSpin may be a major component of a large number of nucleoli in fish growth oocytes. Then, co-localization of CagSpin and β-tubulin was revealed in meiotic spindle of mature egg, indicating that CagSpin is one spindle-associated factor. Moreover, microinjection of CagSpin-specific antibody into the fertilized eggs blocked the first cleavage, and found that the CagSpin depletion resulted in spindle assembly disturbance. Thereby, our study provided the first direct evidence for the critical oocyte-to-embryo transition function of Spin in vertebrates, and confirmed that Spin is one important maternal-effect factor that participates in oocyte growth, oocyte maturation, and oocyte-to-embryo transition.

Analysis on machine tool systems using spindle vibration monitoring for automatic tool changer

OpenAIRE

Shang-Liang Chen; Yin-Ting Cheng; Chin-Fa Su

2015-01-01

Recently, the intelligent systems of technology have become one of the major items in the development of machine tools. One crucial technology is the machinery status monitoring function, which is required for abnormal warnings and the improvement of cutting efficiency. During processing, the mobility act of the spindle unit determines the most frequent and important part such as automatic tool changer. The vibration detection system includes the development of hardware and software, such as ...

Uncovering the Molecular Machinery of the Human Spindle-An Integration of Wet and Dry Systems Biology

DEFF Research Database (Denmark)

Rojas, Ana M.; Santamaria, Anna; Malik, Rainer

2012-01-01

apparatus compared to a success rate of 35% when expert knowledge alone was used. We compare our results to the previously published MitoCheck study and see that our approach does validate some findings by this consortium. Further, we predict so-called "hidden spindle hub'', proteins whose network...

Spindle trees (Euonymus japonica Thunb.) growing in a polluted environment are less sensitive to gamma irradiation

Czech Academy of Sciences Publication Activity Database

Kim, J. K.; Cha, M.; Mukherjee, A.; Wilhelmová, Naděžda

2013-01-01

Roč. 11, č. 4 (2013), s. 233-243 ISSN 2322-3243 Institutional research plan: CEZ:AV0Z50380511 Keywords : Spindle tree * oxidative stress * ionizing radiation Subject RIV: EF - Botanics http://www.ijrr.com/browse.php?a_code=A-10-1-478&slc_lang=en&sid=1

MAX-DOAS measurements of NO2 column densities in Vienna

Science.gov (United States)

Schreier, Stefan; Weihs, Philipp; Peters, Enno; Richter, Andreas; Ostendorf, Mareike; Schönhardt, Anja; Burrows, John P.; Schmalwieser, Alois

2017-04-01

In the VINDOBONA (VIenna horizontal aNd vertical Distribution OBservations Of Nitrogen dioxide and Aerosols) project, two Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) systems will be set up at two different locations and altitudes in Vienna, Austria. After comparison measurements in Bremen, Germany, and Cabauw, The Netherlands, the first of the two MAX-DOAS instruments was set up at the University of Veterinary Medicine in the northeastern part of Vienna in December 2016. The instrument performs spectral measurements of visible scattered sunlight at defined horizontal and vertical viewing directions. From these measurements, column densities of NO2 and aerosols are derived by applying the DOAS analysis. First preliminary results are presented. The second MAX-DOAS instrument will be set up in April/May 2017 at the University of Natural Resources and Life Sciences in the northwestern part of Vienna. Once these two instruments are measuring simultaneously, small campaigns including car DOAS zenith-sky and tower DOAS off-axis measurements are planned. The main emphasis of this project will be on the installation and operation of two MAX-DOAS instruments, the improvement of tropospheric NO2 and aerosol retrieval, and the characterization of the horizontal, vertical, and temporal variations of tropospheric NO2 and aerosols in Vienna, Austria.

Disruption of spindle checkpoint function in rats following 28 days of repeated administration of renal carcinogens.

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Kimura, Masayuki; Mizukami, Sayaka; Watanabe, Yousuke; Hasegawa-Baba, Yasuko; Onda, Nobuhiko; Yoshida, Toshinori; Shibutani, Makoto

2016-02-01

We previously reported that 28-day exposure to hepatocarcinogens that facilitate cell proliferation specifically alters the expression of G1/S checkpoint-related genes and proteins, induces aberrant early expression of ubiquitin D (UBD) at the G2 phase, and increases apoptosis in the rat liver, indicating G1/S and spindle checkpoint dysfunction. The present study aimed to determine the time of onset of carcinogen-specific cell-cycle disruption after repeated administration of renal carcinogens for up to 28 days. Rats were orally administered the renal carcinogens nitrofurantoin (NFT), 1-amino-2,4-dibromoantraquinone (ADAQ), and 1,2,3-trichloropropane (TCP) or the non-carcinogenic renal toxicants 1-chloro-2-propanol, triamterene, and carboxin for 3, 7 or 28 days. Both immunohistochemical single-molecule analysis and real-time RT-PCR analysis revealed that carcinogen-specific expression changes were not observed after 28 days of administration. However, the renal carcinogens ADAQ and TCP specifically reduced the number of cells expressing phosphorylated-histone H3 at Ser10 in both UBD(+) cells and proliferating cells, suggestive of insufficient UBD expression at the M phase and early transition of proliferating cells from the M phase, without increasing apoptosis, after 28 days of administration. In contrast, NFT, which has marginal carcinogenic potential, did not induce such cellular responses. These results suggest that it may take 28 days to induce spindle checkpoint dysfunction by renal carcinogens; however, induction of apoptosis may not be essential. Thus, induction of spindle checkpoint dysfunction may be dependent on carcinogenic potential of carcinogen examined, and marginal carcinogens may not exert sufficient responses even after 28 days of administration.

Human mitochondrial haplogroup H: the highest VO2max consumer--is it a paradox?

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Martínez-Redondo, Diana; Marcuello, Ana; Casajús, José A; Ara, Ignacio; Dahmani, Yahya; Montoya, Julio; Ruiz-Pesini, Eduardo; López-Pérez, Manuel J; Díez-Sánchez, Carmen

2010-03-01

Mitochondrial background has been demonstrated to influence maximal oxygen uptake (VO(2max), in mLkg(-1)min(-1)), but this genetic influence can be compensated for by regular exercise. A positive correlation among electron transport chain (ETC) coupling, ATP and reactive oxygen species (ROS) production has been established, and mitochondrial variants have been reported to show differences in their ETC performance. In this study, we examined in detail the VO(2max) differences found among mitochondrial haplogroups. We recruited 81 healthy male Spanish Caucasian individuals and determined their mitochondrial haplogroup. Their VO(2max) was determined using incremental cycling exercise (ICE). VO(2max) was lower in J than in non-J haplogroup individuals (P=0.04). The H haplogroup was responsible for this difference (VO(2max); J vs. H; P=0.008) and this group also had significantly higher mitochondrial oxidative damage (mtOD) than the J haplogroup (P=0.04). In agreement with these results, VO(2max) and mtOD were positively correlated (P=0.01). Given that ROS production is the major contributor to mtOD and consumes four times more oxygen per electron than the ETC, our results strongly suggest that ROS production is responsible for the higher VO(2max) found in the H variant. These findings not only contribute to a better understanding of the mechanisms underneath VO(2max), but also help to explain some reported associations between mitochondrial haplogroups and mtOD with longevity, sperm motility, premature aging and susceptibility to different pathologies.

On the spectrum in max algebra

Czech Academy of Sciences Publication Activity Database

Müller, Vladimír; Peperko, A.

2015-01-01

Roč. 485, November (2015), s. 250-266 ISSN 0024-3795 R&D Projects: GA ČR(CZ) GA14-07880S Institutional support: RVO:67985840 Keywords : non-negativ matrices * max algebra * eigenvalues Subject RIV: BA - General Mathematics Impact factor: 0.965, year: 2015 http://www.sciencedirect.com/science/article/pii/S0024379515004139

Temporal and SUMO-specific SUMOylation contribute to the dynamics of Polo-like kinase 1 (PLK1) and spindle integrity during mouse oocyte meiosis.

Science.gov (United States)

Feitosa, Weber Beringui; Hwang, KeumSil; Morris, Patricia L

2018-02-15

During mammalian meiosis, Polo-like kinase 1 (PLK1) is essential during cell cycle progression. In oocyte maturation, PLK1 expression is well characterized but timing of posttranslational modifications regulating its activity and subcellular localization are less clear. Small ubiquitin-related modifier (SUMO) posttranslational modifier proteins have been detected in mammalian gametes but their precise function during gametogenesis is largely unknown. In the present paper we report for mouse oocytes that both PLK1 and phosphorylated PLK1 undergo SUMOylation in meiosis II (MII) oocytes using immunocytochemistry, immunoprecipitation and in vitro SUMOylation assays. At MII, PLK1 is phosphorylated at threonine-210 and serine-137. MII oocyte PLK1 and phosphorylated PLK1 undergo SUMOylation by SUMO-1, -2 and -3 as shown by individual in vitro assays. Using these assays, forms of phosphorylated PLK1 normalized to PLK1 increased significantly and correlated with SUMOylated PLK1 levels. During meiotic progression and maturation, SUMO-1-SUMOylation of PLK1 is involved in spindle formation whereas SUMO-2/3-SUMOylation may regulate PLK1 activity at kinetochore-spindle attachment sites. Microtubule integrity is required for PLK1 localization with SUMO-1 but not with SUMO-2/3. Inhibition of SUMOylation disrupts proper meiotic bipolar spindle organization and spindle-kinetochore attachment. The data show that both temporal and SUMO-specific-SUMOylation play important roles in orchestrating functional dynamics of PLK1 during mouse oocyte meiosis, including subcellular compartmentalization. Copyright © 2018 Elsevier Inc. All rights reserved.

MAXIMAL OXIGEN UPTAKE (VO2 MAX AS THE INDICATOR OF PHYSICAL WORKING CAPACITY IN SPORTSMEN

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Zvezdana Rajkovaca

2005-12-01

Full Text Available The term “aerobic capacity” represents the sum of aerobic metabolic processes in human organism. It is the basis of the physical working capacity. Value of the maximal oxygen uptake (VO2max is the best indicator for the aerobic capacity evaluation.The purpose of this study was to check the possibility of using VO2max as the indicator of aerobic capacity in sportsmen and to check differences in VO2max values in regard to non-sportsmen.The goals were: 1.Analyses of the VO2max values in sportsmen of various sports 2. Comparison of values of sportsmen with the values of non-sportsmen.This study included 67 sportsmen (rowers, football players and judoists and 28 nonsportsmen. VO2max was measured by using a direct method.The results obtained show statistically higher VO2max values in rowers (4,52 L/min - 55,8 mL/kg/min in regard to football players (4,2 L/min – 53,6 mL/kg/min, judoists (3,58 L/min - 47,2 mL/ kg/min and non-sportsmen (3,28 L/min – 42,3 mL/kg/min. Successful rowing requires high anaerobic capacity and, therefore, high VO2max.These results show higher values of VO2max in sportsmen in regard to non-sportsmen, which is the result of training only.

The relationship between cell killing, chromosome aberrations, spindle defects, and mitotic delay in mouse lymphoma cells of differential sensitivity to X-rays

International Nuclear Information System (INIS)

Scott, D.; Zampetti-Bosseler, F.

1980-01-01

A study has been made of the effects of x radiation on an ultrasensitive subline of L5178Y mouse lymphoma cells. It has been shown that at survival levels above about 20 per cent, chromosome structural aberrations which lead to bridges and fragments at anaphase are about four times more frequent than spindle defects. The results demonstrated the higher frequency of structural aberrations and spindle defects, and the greater mitotic delay in the X-ray-sensitive than in the X-ray-resistant cell line. A model is proposed which causally relates these end-points to cell killing and DNA repair. (author)

Cellular angiofibroma: analysis of 25 cases emphasizing its relationship to spindle cell lipoma and mammary-type myofibroblastoma

NARCIS (Netherlands)

Flucke, U.E.; Krieken, J.H. van; Mentzel, T.

2011-01-01

Cellular angiofibroma represents a rare benign mesenchymal tumor, occurring mainly in the superficial soft tissue of the genital region. The involvement of 13q14 in some cases confirmed the morphological suggested link with spindle cell lipoma and mammary-type myofibroblastoma. We analyzed the

Time-sequential observation of spindle and phragmoplast orientation in BY-2 cells with altered cortical actin microfilament patterning.

Science.gov (United States)

Kojo, Kei H; Yasuhara, Hiroki; Hasezawa, Seiichiro

2014-01-01

Precise division plane determination is essential for plant development. At metaphase, a dense actin microfilament meshwork appears on both sides of the cell center, forming a characteristic cortical actin microfilament twin peak pattern in BY-2 cells. We previously reported a strong correlation between altered cortical actin microfilament patterning and an oblique mitotic spindle orientation, implying that these actin microfilament twin peaks play a role in the regulation of mitotic spindle orientation. In the present study, time-sequential observation was used to reveal the progression from oblique phragmoplast to oblique cell plate orientation in cells with altered cortical actin microfilament patterning. In contrast to cells with normal actin microfilament twin peaks, oblique phragmoplast reorientation was rarely observed in cells with altered cortical actin microfilament patterning. These results support the important roles of cortical actin microfilament patterning in division plane orientation.

The effect of cloud screening on MAX-DOAS aerosol retrievals.

Science.gov (United States)

Gielen, Clio; Van Roozendael, Michel; Hendrik, Francois; Fayt, Caroline; Hermans, Christian; Pinardi, Gaia; De Backer, Hugo; De Bock, Veerle; Laffineur, Quentin; Vlemmix, Tim

2014-05-01

In recent years, ground-based multi-axis differential absorption spectroscopy (MAX-DOAS) has shown to be ideally suited for the retrieval of tropospheric trace gases and deriving information on the aerosol properties. These measurements are invaluable to our understanding of the physics and chemistry of the atmospheric system, and the impact on the Earth's climate. Unfortunately, MAX-DOAS measurements are often performed under strong non-clear-sky conditions, causing strong data quality degradation and uncertainties on the retrievals. Here we present the result of our cloud-screening method, using the colour index (CI), on aerosol retrievals from MAX-DOAS measurements (AOD and vertical profiles). We focus on two large data sets, from the Brussels and Beijing area. Using the CI we define 3 different sky conditions: bad (=full thick cloud cover/extreme aerosols), mediocre (=thin clouds/aerosols) and good (=clear sky). We also flag the presence of broken/scattered clouds. We further compare our cloud-screening method with results from cloud-cover fractions derived from thermic infrared measurements. In general, our method shows good results to qualify the sky and cloud conditions of MAX-DOAS measurements, without the need for other external cloud-detection systems. Removing data under bad-sky and broken-cloud conditions results in a strongly improved agreement, in both correlation and slope, between the MAX-DOAS aerosol retrievals and data from other instruments (e.g. AERONET, Brewer). With the improved AOD retrievals, the seasonal and diurnal variations of the aerosol content and vertical distribution at both sites can be investigated in further detail. By combining with additional information derived by other instruments (Brewer, lidar, ...) operated at the stations, we will further study the observed aerosol characteristics, and their influence on and by meteorological conditions such as clouds and/or the boundary layer height.

QoS Management and Control for an All-IP WiMAX Network Architecture: Design, Implementation and Evaluation

Directory of Open Access Journals (Sweden)

Thomas Michael Bohnert

2008-01-01

Full Text Available The IEEE 802.16 standard provides a specification for a fixed and mobile broadband wireless access system, offering high data rate transmission of multimedia services with different Quality-of-Service (QoS requirements through the air interface. The WiMAX Forum, going beyond the air interface, defined an end-to-end WiMAX network architecture, based on an all-IP platform in order to complete the standards required for a commercial rollout of WiMAX as broadband wireless access solution. As the WiMAX network architecture is only a functional specification, this paper focuses on an innovative solution for an end-to-end WiMAX network architecture offering in compliance with the WiMAX Forum specification. To our best knowledge, this is the first WiMAX architecture built by a research consortium globally and was performed within the framework of the European IST project WEIRD (WiMAX Extension to Isolated Research Data networks. One of the principal features of our architecture is support for end-to-end QoS achieved by the integration of resource control in the WiMAX wireless link and the resource management in the wired domains in the network core. In this paper we present the architectural design of these QoS features in the overall WiMAX all-IP framework and their functional as well as performance evaluation. The presented results can safely be considered as unique and timely for any WiMAX system integrator.

The Dangers of Estimating V˙O2max Using Linear, Nonexercise Prediction Models.

Science.gov (United States)

Nevill, Alan M; Cooke, Carlton B

2017-05-01

This study aimed to compare the accuracy and goodness of fit of two competing models (linear vs allometric) when estimating V˙O2max (mL·kg·min) using nonexercise prediction models. The two competing models were fitted to the V˙O2max (mL·kg·min) data taken from two previously published studies. Study 1 (the Allied Dunbar National Fitness Survey) recruited 1732 randomly selected healthy participants, 16 yr and older, from 30 English parliamentary constituencies. Estimates of V˙O2max were obtained using a progressive incremental test on a motorized treadmill. In study 2, maximal oxygen uptake was measured directly during a fatigue limited treadmill test in older men (n = 152) and women (n = 146) 55 to 86 yr old. In both studies, the quality of fit associated with estimating V˙O2max (mL·kg·min) was superior using allometric rather than linear (additive) models based on all criteria (R, maximum log-likelihood, and Akaike information criteria). Results suggest that linear models will systematically overestimate V˙O2max for participants in their 20s and underestimate V˙O2max for participants in their 60s and older. The residuals saved from the linear models were neither normally distributed nor independent of the predicted values nor age. This will probably explain the absence of a key quadratic age term in the linear models, crucially identified using allometric models. Not only does the curvilinear age decline within an exponential function follow a more realistic age decline (the right-hand side of a bell-shaped curve), but the allometric models identified either a stature-to-body mass ratio (study 1) or a fat-free mass-to-body mass ratio (study 2), both associated with leanness when estimating V˙O2max. Adopting allometric models will provide more accurate predictions of V˙O2max (mL·kg·min) using plausible, biologically sound, and interpretable models.

Cinética do consumo de oxigênio e tempo limite na vvo2max: comparação entre homens e mulheres Oxygen uptake kinetics and threshold time at the vVO2max: tomparison between men and women

Directory of Open Access Journals (Sweden)

Paulo Henrique Silva Marques de Azevedo

2010-08-01

Full Text Available Foi investigada a influência do gênero no tempo limite (Tlim e na cinética do VO2 durante corrida na velocidade associada ao VO2max (vVO2max em nove homens e nove mulheres, todos adultos, jovens e sedentários, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolante, sendo um teste incremental para determinar VO2max (42,66 ± 4,50 vs. 32,92 ± 6,03mL.kg-1.min-1 e vVO2max (13.2 ± 1.5 vs. 10,3 ± 2,0km.h-1, respectivamente. Um segundo teste com carga constante na vVO2max até a exaustão. O Tlim e a cinética do VO2 foram determinados. Não houve diferença significante entre homens e mulheres para constante de tempo (τ (35,76 ± 21,03 vs. 36,5 ± 6,21s, respectivamente; P = 0,29; Tlim (308 ± 84,3 vs. 282,11 ± 57,19s, respectivamente; P = 0,68, tempo para atingir o VO2max (TAVO2max (164,48 ± 96,73 vs. 167,88 ± 28,59s, respectivamente; P = 0,29, tempo para atingir o VO2max em percentual do Tlim (%Tlim (50,24 ± 16,93 vs. 62,63 ± 16,60%, respectivamente; P = 0,19, tempo mantido no VO2max (TMVO2max (144,08 ± 42,55 vs. 114,23 ± 76,96s, respectivamente; P = 0,13. Estes resultados sugerem que a cinética do VO2 e o Tlim são similares entre homens e mulheres sedentários na vVO2max.The aim of this study was to investigate the influence of gender on Tthre and VO2 response during running exercise performed at vVO2max. Therefore, eighteen untrained individuals (9 male and 9 female with normal weight and aged between 20 - 30 years (VO2max = 42.66 ± 4.50 vs 32.92 ± 6.03 mL.kg-1.min-1 and vVO2max = 13.2 ± 1.5 vs 10.3 ± 2.0 km.h-1, for male and female, respectively were assessed. Subjects performed two exercise tests on treadmill. First one was an incremental test to determine VO2max, velocity at VO2max (vVO2max and second test was performed at steady velocity - vVO2max - until exhaustion. The threshold time (Tthre and VO2 kinetics response was determined. No significant differences were observed between men

Higher Drop in Speed during a Repeated Sprint Test in Soccer Players Reporting Former Hamstring Strain Injury

Science.gov (United States)

Røksund, Ola D.; Kristoffersen, Morten; Bogen, Bård E.; Wisnes, Alexander; Engeseth, Merete S.; Nilsen, Ann-Kristin; Iversen, Vegard V.; Mæland, Silje; Gundersen, Hilde

2017-01-01

Aim: Hamstring strain injury is common in soccer. The aim of this study was to evaluate the physical capacity of players who have and have not suffered from hamstring strain injury in a sample of semi-professional and professional Norwegian soccer players in order to evaluate characteristics and to identify possible indications of insufficient rehabilitation. Method: Seventy-five semi-professional and professional soccer players (19 ± 3 years) playing at the second and third level in the Norwegian league participated in the study. All players answered a questionnaire, including one question about hamstring strain injury (yes/no) during the previous 2 years. They also performed a 40 m maximal sprint test, a repeated sprint test (8 × 20 m), a countermovement jump, a maximal oxygen consumption (VO2max) test, strength tests and flexibility tests. Independent sample t-tests were used to evaluate differences in the physical capacity of the players who had suffered from hamstring strain injury and those who had not. Mixed between-within subject's analyses of variance was used to compare changes in speed during the repeated sprint test between groups. Results: Players who reported hamstring strain injury during the previous two years (16%) had a significantly higher drop in speed (0.07 vs. 0.02 s, p = 0.007) during the repeated sprint test, compared to players reporting no previous hamstring strain injury. In addition, there was a significant interaction (groups × time) (F = 3.22, p = 0.002), showing that speed in the two groups changed differently during the repeated sprint test. There were no significant differences in relations to age, weight, height, body fat, linear speed, countermovement jump height, leg strength, VO2max, or hamstring flexibility between the groups. Conclusion: Soccer players who reported hamstring strain injury during the previous 2 years showed significant higher drop in speed during the repeated sprint test compared to players with no hamstring

[Psychiatry as cultural science: considerations following Max Weber].

Science.gov (United States)

Bormuth, M

2010-11-01

Psychiatry can be seen as a natural and cultural science. According to this the postulate of freedom is its strong value judgment. Since the times of enlightenment it has been described metaphorically by the myth of the expulsion from Paradise. Following Max Weber and Wilhelm Dilthey, Karl Jaspers has introduced this perspective into psychiatry. His strict dichotomy between explaining and understanding has later been critically revised by Werner Janzarik and Hans Heimann. Their concepts of structure dynamic, of pathography and of anthropology are closer to Max Weber who connected natural and cultural sciences in a much stronger way. Especially the pathographic example of Nietzsche allows to demonstrate the differences between Jaspers and the later psychopathologists of the Heidelberg and Tübingen schools.

Human papillomavirus type 16 E7 oncoprotein engages but does not abrogate the mitotic spindle assembly checkpoint

Energy Technology Data Exchange (ETDEWEB)

Yu, Yueyang [Division of Infectious Diseases, Brigham and Women' s Hospital and Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115 (United States); Munger, Karl, E-mail: kmunger@rics.bwh.harvard.edu [Division of Infectious Diseases, Brigham and Women' s Hospital and Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115 (United States)

2012-10-10

The mitotic spindle assembly checkpoint (SAC) ensures faithful chromosome segregation during mitosis by censoring kinetochore-microtubule interactions. It is frequently rendered dysfunctional during carcinogenesis causing chromosome missegregation and genomic instability. There are conflicting reports whether the HPV16 E7 oncoprotein drives chromosomal instability by abolishing the SAC. Here we report that degradation of mitotic cyclins is impaired in cells with HPV16 E7 expression. RNAi-mediated depletion of Mad2 or BubR1 indicated the involvement of the SAC, suggesting that HPV16 E7 expression causes sustained SAC engagement. Mutational analyses revealed that HPV16 E7 sequences that are necessary for retinoblastoma tumor suppressor protein binding as well as sequences previously implicated in binding the nuclear and mitotic apparatus (NuMA) protein and in delocalizing dynein from the mitotic spindle contribute to SAC engagement. Importantly, however, HPV16 E7 does not markedly compromise the SAC response to microtubule poisons.

NiMax: a new approach to develop hadronic event generators in HEP

International Nuclear Information System (INIS)

Amelin, N.; Komogorov, M.

2000-01-01

The NiMax framework is a new approach to develop, assemble and use hadronic event generators in HEP. There are several important concepts of the NiMax architecture: the components, the data file, the application domain module, the control system and the project. Here we describe these concepts stressing their functionality

Life Cycle Characterization of Sulfolobus Monocaudavirus 1, an Extremophilic Spindle-Shaped Virus with Extracellular Tail Development.

Science.gov (United States)

Uldahl, Kristine B; Jensen, Signe B; Bhoobalan-Chitty, Yuvaraj; Martínez-Álvarez, Laura; Papathanasiou, Pavlos; Peng, Xu

2016-06-15

We provide here, for the first time, insights into the initial infection stages of a large spindle-shaped archaeal virus and explore the following life cycle events. Our observations suggest that Sulfolobus monocaudavirus 1 (SMV1) exhibits a high adsorption rate and that virions adsorb to the host cells via three distinct attachment modes: nosecone association, body association, and body/tail association. In the body/tail association mode, the entire virion, including the tail(s), aligns to the host cell surface and the main body is greatly flattened, suggesting a possible fusion entry mechanism. Upon infection, the intracellular replication cycle lasts about 8 h, at which point the virions are released as spindle-shaped tailless particles. Replication of the virus retarded host growth but did not cause lysis of the host cells. Once released from the host and at temperatures resembling that of its natural habitat, SMV1 starts developing one or two tails. This exceptional property of undergoing a major morphological development outside, and independently of, the host cell has been reported only once before for the related Acidianus two-tailed virus. Here, we show that SMV1 can develop tails of more than 900 nm in length, more than quadrupling the total virion length. Very little is known about the initial life cycle stages of viruses infecting hosts of the third domain of life, Archaea This work describes the first example of an archaeal virus employing three distinct association modes. The virus under study, Sulfolobus monocaudavirus 1, is a representative of the large spindle-shaped viruses that are frequently found in acidic hot springs. The results described here will add valuable knowledge about Archaea, the least studied domain in the virology field. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

When the genome plays dice: circumvention of the spindle assembly checkpoint and near-random chromosome segregation in multipolar cancer cell mitoses.

Science.gov (United States)

Gisselsson, David; Håkanson, Ulf; Stoller, Patrick; Marti, Dominik; Jin, Yuesheng; Rosengren, Anders H; Stewénius, Ylva; Kahl, Fredrik; Panagopoulos, Ioannis

2008-04-02

Normal cell division is coordinated by a bipolar mitotic spindle, ensuring symmetrical segregation of chromosomes. Cancer cells, however, occasionally divide into three or more directions. Such multipolar mitoses have been proposed to generate genetic diversity and thereby contribute to clonal evolution. However, this notion has been little validated experimentally. Chromosome segregation and DNA content in daughter cells from multipolar mitoses were assessed by multiphoton cross sectioning and fluorescence in situ hybridization in cancer cells and non-neoplastic transformed cells. The DNA distribution resulting from multipolar cell division was found to be highly variable, with frequent nullisomies in the daughter cells. Time-lapse imaging of H2B/GFP-labelled multipolar mitoses revealed that the time from the initiation of metaphase to the beginning of anaphase was prolonged and that the metaphase plates often switched polarity several times before metaphase-anaphase transition. The multipolar metaphase-anaphase transition was accompanied by a normal reduction of cellular cyclin B levels, but typically occurred before completion of the normal separase activity cycle. Centromeric AURKB and MAD2 foci were observed frequently to remain on the centromeres of multipolar ana-telophase chromosomes, indicating that multipolar mitoses were able to circumvent the spindle assembly checkpoint with some sister chromatids remaining unseparated after anaphase. Accordingly, scoring the distribution of individual chromosomes in multipolar daughter nuclei revealed a high frequency of nondisjunction events, resulting in a near-binomial allotment of sister chromatids to the daughter cells. The capability of multipolar mitoses to circumvent the spindle assembly checkpoint system typically results in a near-random distribution of chromosomes to daughter cells. Spindle multipolarity could thus be a highly efficient generator of genetically diverse minority clones in transformed cell

When the genome plays dice: circumvention of the spindle assembly checkpoint and near-random chromosome segregation in multipolar cancer cell mitoses.

Directory of Open Access Journals (Sweden)

David Gisselsson

Full Text Available BACKGROUND: Normal cell division is coordinated by a bipolar mitotic spindle, ensuring symmetrical segregation of chromosomes. Cancer cells, however, occasionally divide into three or more directions. Such multipolar mitoses have been proposed to generate genetic diversity and thereby contribute to clonal evolution. However, this notion has been little validated experimentally. PRINCIPAL FINDINGS: Chromosome segregation and DNA content in daughter cells from multipolar mitoses were assessed by multiphoton cross sectioning and fluorescence in situ hybridization in cancer cells and non-neoplastic transformed cells. The DNA distribution resulting from multipolar cell division was found to be highly variable, with frequent nullisomies in the daughter cells. Time-lapse imaging of H2B/GFP-labelled multipolar mitoses revealed that the time from the initiation of metaphase to the beginning of anaphase was prolonged and that the metaphase plates often switched polarity several times before metaphase-anaphase transition. The multipolar metaphase-anaphase transition was accompanied by a normal reduction of cellular cyclin B levels, but typically occurred before completion of the normal separase activity cycle. Centromeric AURKB and MAD2 foci were observed frequently to remain on the centromeres of multipolar ana-telophase chromosomes, indicating that multipolar mitoses were able to circumvent the spindle assembly checkpoint with some sister chromatids remaining unseparated after anaphase. Accordingly, scoring the distribution of individual chromosomes in multipolar daughter nuclei revealed a high frequency of nondisjunction events, resulting in a near-binomial allotment of sister chromatids to the daughter cells. CONCLUSION: The capability of multipolar mitoses to circumvent the spindle assembly checkpoint system typically results in a near-random distribution of chromosomes to daughter cells. Spindle multipolarity could thus be a highly efficient

A linear programming approach to max-sum problem: a review.

Science.gov (United States)

Werner, Tomás

2007-07-01

The max-sum labeling problem, defined as maximizing a sum of binary (i.e., pairwise) functions of discrete variables, is a general NP-hard optimization problem with many applications, such as computing the MAP configuration of a Markov random field. We review a not widely known approach to the problem, developed by Ukrainian researchers Schlesinger et al. in 1976, and show how it contributes to recent results, most importantly, those on the convex combination of trees and tree-reweighted max-product. In particular, we review Schlesinger et al.'s upper bound on the max-sum criterion, its minimization by equivalent transformations, its relation to the constraint satisfaction problem, the fact that this minimization is dual to a linear programming relaxation of the original problem, and the three kinds of consistency necessary for optimality of the upper bound. We revisit problems with Boolean variables and supermodular problems. We describe two algorithms for decreasing the upper bound. We present an example application for structural image analysis.

Using MaxCompiler for the high level synthesis of trigger algorithms

International Nuclear Information System (INIS)

Summers, S.; Rose, A.; Sanders, P.

2017-01-01

Firmware for FPGA trigger applications at the CMS experiment is conventionally written using hardware description languages such as Verilog and VHDL. MaxCompiler is an alternative, Java based, tool for developing FPGA applications which uses a higher level of abstraction from the hardware than a hardware description language. An implementation of the jet and energy sum algorithms for the CMS Level-1 calorimeter trigger has been written using MaxCompiler to benchmark against the VHDL implementation in terms of accuracy, latency, resource usage, and code size. A Kalman Filter track fitting algorithm has been developed using MaxCompiler for a proposed CMS Level-1 track trigger for the High-Luminosity LHC upgrade. The design achieves a low resource usage, and has a latency of 187.5 ns per iteration.

Using MaxCompiler for the high level synthesis of trigger algorithms

Science.gov (United States)

Summers, S.; Rose, A.; Sanders, P.

2017-02-01

Firmware for FPGA trigger applications at the CMS experiment is conventionally written using hardware description languages such as Verilog and VHDL. MaxCompiler is an alternative, Java based, tool for developing FPGA applications which uses a higher level of abstraction from the hardware than a hardware description language. An implementation of the jet and energy sum algorithms for the CMS Level-1 calorimeter trigger has been written using MaxCompiler to benchmark against the VHDL implementation in terms of accuracy, latency, resource usage, and code size. A Kalman Filter track fitting algorithm has been developed using MaxCompiler for a proposed CMS Level-1 track trigger for the High-Luminosity LHC upgrade. The design achieves a low resource usage, and has a latency of 187.5 ns per iteration.

Relationship between running kinematic changes and time limit at vVO2max

Directory of Open Access Journals (Sweden)

Leonardo De Lucca

2012-06-01

Exhaustive running at maximal oxygen uptake velocity (vVO2max can alter running kinematic parameters and increase energy cost along the time. The aims of the present study were to compare characteristics of ankle and knee kinematics during running at vVO2max and to verify the relationship between changes in kinematic variables and time limit (Tlim. Eleven male volunteers, recreational players of team sports, performed an incremental running test until volitional exhaustion to determine vVO2max and a constant velocity test at vVO2max. Subjects were filmed continuously from the left sagittal plane at 210 Hz for further kinematic analysis. The maximal plantar flexion during swing (p<0.01 was the only variable that increased significantly from beginning to end of the run. Increase in ankle angle at contact was the only variable related to Tlim (r=0.64; p=0.035 and explained 34% of the performance in the test. These findings suggest that the individuals under study maintained a stable running style at vVO2max and that increase in plantar flexion explained the performance in this test when it was applied in non-runners.

The conserved Wdr8-hMsd1/SSX2IP complex localises to the centrosome and ensures proper spindle length and orientation

International Nuclear Information System (INIS)

Hori, Akiko; Morand, Agathe; Ikebe, Chiho; Frith, David; Snijders, Ambrosius P.; Toda, Takashi

2015-01-01

The centrosome plays a pivotal role in a wide range of cellular processes and its dysfunction is causally linked to many human diseases including cancer and developmental and neurological disorders. This organelle contains more than one hundred components, and yet many of them remain uncharacterised. Here we identified a novel centrosome protein Wdr8, based upon the structural conservation of the fission yeast counterpart. We showed that Wdr8 constitutively localises to the centrosome and super resolution microscopy uncovered that this protein is enriched at the proximal end of the mother centriole. Furthermore, we identified hMsd1/SSX2IP, a conserved spindle anchoring protein, as one of Wdr8 interactors by mass spectrometry. Wdr8 formed a complex and partially colocalised with hMsd1/SSX2IP. Intriguingly, knockdown of Wdr8 or hMsd1/SSX2IP displayed very similar mitotic defects, in which spindle microtubules became shortened and misoriented. Indeed, Wdr8 depletion resulted in the reduced recruitment of hMsd1/SSX2IP to the mitotic centrosome, though the converse is not true. Together, we propose that the conserved Wdr8-hMsd1/SSX2IP complex plays a critical role in controlling proper spindle length and orientation. - Highlights: • Human Wdr8 is a centrosomal protein enriched in the proximal end of the centriole. • Wdr8 and hMsd1/SSX2IP form a complex conserved in fungi. • Depletion of Wdr8 results in shorter, tilted spindle microtubules. • Depletion phenotypes of Wdr8 are very similar to those of hMsd1/SSX2IP knockdown.

The conserved Wdr8-hMsd1/SSX2IP complex localises to the centrosome and ensures proper spindle length and orientation

Energy Technology Data Exchange (ETDEWEB)

Hori, Akiko; Morand, Agathe; Ikebe, Chiho; Frith, David; Snijders, Ambrosius P.; Toda, Takashi, E-mail: takashi-toda@hiroshima-u.ac.jp

2015-12-04

The centrosome plays a pivotal role in a wide range of cellular processes and its dysfunction is causally linked to many human diseases including cancer and developmental and neurological disorders. This organelle contains more than one hundred components, and yet many of them remain uncharacterised. Here we identified a novel centrosome protein Wdr8, based upon the structural conservation of the fission yeast counterpart. We showed that Wdr8 constitutively localises to the centrosome and super resolution microscopy uncovered that this protein is enriched at the proximal end of the mother centriole. Furthermore, we identified hMsd1/SSX2IP, a conserved spindle anchoring protein, as one of Wdr8 interactors by mass spectrometry. Wdr8 formed a complex and partially colocalised with hMsd1/SSX2IP. Intriguingly, knockdown of Wdr8 or hMsd1/SSX2IP displayed very similar mitotic defects, in which spindle microtubules became shortened and misoriented. Indeed, Wdr8 depletion resulted in the reduced recruitment of hMsd1/SSX2IP to the mitotic centrosome, though the converse is not true. Together, we propose that the conserved Wdr8-hMsd1/SSX2IP complex plays a critical role in controlling proper spindle length and orientation. - Highlights: • Human Wdr8 is a centrosomal protein enriched in the proximal end of the centriole. • Wdr8 and hMsd1/SSX2IP form a complex conserved in fungi. • Depletion of Wdr8 results in shorter, tilted spindle microtubules. • Depletion phenotypes of Wdr8 are very similar to those of hMsd1/SSX2IP knockdown.

Environmental Assessment for Mid-Bay Bridge Connector, Eglin Air Force Base, Florida

Science.gov (United States)

2008-12-05

Year Average Speed (mph) AADT VPH Receptor Max 1-Hr Conc (ppm) Max 8-Hr Conc (ppm) Proposed Action 2001 45 17,400 981 Proposed...Speed (mph) AADT VPH Receptor Max 1-Hr Conc (ppm) Max 8-Hr Conc (ppm) Alternative C 2001 45 17,400 981 Proposed Intersection at SR 20...Alternative Traffic Volumes Alternative Year Average Speed White Point Road (mph) AADT VPH Receptor Max 1-Hr Conc (ppm) Max 8-Hr Conc (ppm

Analysis of the failure of a vacuum spin-pit drive turbine spindle shaft

OpenAIRE

Pettitt, Jason M.

2005-01-01

The Naval Postgraduate School's Rotor Spin Research Facility experienced a failure in the Spring of 2005 in which the rotor dropped from the drive turbine and caused extensive damage. A failure analysis of the drive turbine spindle shaft was conducted in order to determine the cause of failure: whether due to a material or design flaw. Also, a dynamic analysis was conducted in order to determine the natural modes present in the system and the associated frequencies that could have contributed...

An unusual and spectacular case of spindle cell lipoma of the posterior neck invading the spinal cervical canal and posterior cranial fossa.

Science.gov (United States)

Petit, Damien; Menei, Philippe; Fournier, Henri-Dominique

2011-11-01

The authors describe the first case of spindle cell lipoma of the posterior neck invading the upper cervical spinal canal and the posterior cranial fossa. Spindle cell lipoma is an extremely rare variant of benign lipoma. It usually occurs as a solitary subcutaneous well-circumscribed lesion in the posterior neck or shoulders of adult men. Local aggressiveness is unusual. This 61-year-old man presented with an increased left cerebellar syndrome and headaches. He also had a posterior neck tumefaction, which had been known about for a long time. Computed tomography and MR imaging studies revealed a voluminous mass extending to the upper cervical canal and posterior cranial fossa and eroding the neighboring bones. The lesion was well delimited, and contrast enhancement was intense and heterogeneous. The tumor, which had initially developed under the muscles of the posterior neck, was totally resected. Histological assessment revealed numerous fat cells with spindle cells secreting collagen. The large size of the tumor and the submuscular location, bone erosion, and compression of the CNS were unusual in this rare subtype of benign adipose tumor. Its presentation could simulate a sarcoma.

Mini MAX-DOAS Measurements of Air Pollutants over China

Science.gov (United States)

Staadt, Steffen; Hao, Nan; Trautmann, Thomas

2016-08-01

This study continues the work of Clémer et al., (2010) and is aimed to improve trace gas retrievals with mini MAX-DOAS measurements in Nanjing. Based on that work, aerosol extinction vertical profiles are retrieved using the bePRO inversion algorithm developed by the Royal Belgian Institute for Space Aeronomy (BIRA- IASB). Afterwards, the tropospheric trace gas vertical profiles and vertical column densities (VCDs) are retrieved by applying the optimal estimation method to the O4 MAX-DOAS measurements. The Profiles for N O2 , S O2 , glyoxal, formaldehyde and nitrous acid are obtained with different results and different settings for the DOAS measurement. The AODs show small positive correlation against the AERONET values. For NO2, the retrieval shows reasonable concentrations in winter as opposed to summer and has small positive correlations with GOME-2 data. The SO2 VCDs are not correlated with the GOME-2 data, due to high uncertainties from MAX-DOAS and satellite retrievals, while the vertical mixing ratios (VMR) show good agreement with in-situ data (SORPES) at Nanjing. Nitrous acid shows a maximum in winter and a minimum in summer, while glyoxal has its maximum in August and September.

A max version of Perron--Frobenius theorem for nonnegative tensor

OpenAIRE

Afshin, Hamid Reza; Shojaeifard, Ali Reza

2015-01-01

In this paper we generalize the max algebra system of nonnegative matrices to the class of nonnegative tensors and derive its fundamental properties. If $\\mathbb{A} \\in \\Re_ + ^{\\left[ {m,n} \\right]}$ is a nonnegative essentially positive tensor such that satisfies the condition class NC, we prove that there exist $\\mu \\left( \\mathbb{A} \\right)$ and a corresponding positive vector $x$ such that $\\mathop {\\max }\\limits_{1 \\le{i_2}\\cdots {i_m} \\le n} \\left\\{ {{a_{i{i_2}\\cdots {i_m}}}{x_{{i_2}}}...