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Sample records for optical angle clamp

  1. Angle-deviation optical profilometer

    Institute of Scientific and Technical Information of China (English)

    Chen-Tai Tan; Yuan-Sheng Chan; Zhen-Chin Lin; Ming-Hung Chiu

    2011-01-01

    @@ We propose a new optical profilometer for three-dimensional (3D) surface profile measurement in real time.The deviation angle is based on geometrical optics and is proportional to the apex angle of a test plate.Measuring the reflectivity of a parallelogram prism allows detection of the deviation angle when the beam is incident at the nearby critical angle. The reflectivity is inversely proportional to the deviation angle and proportional to the apex angle and surface height. We use a charge-coupled device (CCD) camera at the image plane to capture the reflectivity profile and obtain the 3D surface profile directly.%We propose a new optical profilometer for three-dimensional (3D) surface profile measurement in real time.The deviation angle is based on geometrical optics and is proportional to the apex angle of a test plate.Measuring the refiectivity of a parallelogram prism allows detection of the deviation angle when the beam is incident at the nearby critical angle. The refiectivity is inversely proportional to the deviation angle and proportional to the apex angle and surface height. We use a charge-coupled device (CCD) camera at the image plane to capture the refiectivity profile and obtain the 3D surface profile directly.

  2. Implementation and Tuning of an Optical Tweezers Force-Clamp Feedback System.

    Science.gov (United States)

    Bugiel, Michael; Jannasch, Anita; Schäffer, Erik

    2017-01-01

    Feedback systems can be used to control the value of a system variable. In optical tweezers, active feedback is often implemented to either keep the position or tension applied to a single biomolecule constant. Here, we describe the implementation of the latter: an optical force-clamp setup that can be used to study the motion of processive molecular motors under a constant load. We describe the basics of a software-implemented proportional-integral-derivative (PID) controller, how to tune it, and how to determine its optimal feedback rate. Limitations, possible feed-forward applications, and extensions into two- and three-dimensional optical force clamps are discussed. The feedback is ultimately limited by thermal fluctuations and the compliance of the involved molecules. To investigate a particular mechanical process, understanding the basics and limitations of the feedback system will be helpful for choosing the proper feedback hardware, for optimizing the system parameters, and for the design of the experiment.

  3. Detailed Theoretical Model for Adjustable Gain-Clamped Semiconductor Optical Amplifier

    Directory of Open Access Journals (Sweden)

    Lin Liu

    2012-01-01

    Full Text Available The adjustable gain-clamped semiconductor optical amplifier (AGC-SOA uses two SOAs in a ring-cavity topology: one to amplify the signal and the other to control the gain. The device was designed to maximize the output saturated power while adjusting gain to regulate power differences between packets without loss of linearity. This type of subsystem can be used for power equalisation and linear amplification in packet-based dynamic systems such as passive optical networks (PONs. A detailed theoretical model is presented in this paper to simulate the operation of the AGC-SOA, which gives a better understanding of the underlying gain clamping mechanics. Simulations and comparisons with steady-state and dynamic gain modulation experimental performance are given which validate the model.

  4. Angle-resolved optical coherence tomography

    Science.gov (United States)

    Desjardins, Adrien Emmanuel

    Optical coherence tomography (OCT) has emerged as a powerful tool for probing the microstructure of biological tissue non-invasively at high-speed. OCT measures depth-resolved reflectance of infrared light, generating cross-sectional images non-invasively with micron-scale resolution. As with other imaging modalities that employ coherent detection, OCT images are confounded by speckle noise. Speckle imposes a grainy texture on images that reduces the signal-to-noise ratio to near unity values. As a result, it conceals subtle differences in scattering properties known to be crucial for differentiating normal from diseased tissue states. In this thesis, we developed a novel OCT modality called "Angle-Resolved OCT" in which depth scans (A-lines) are obtained simultaneously from a broad range of backscattering angles. We demonstrated that high levels of speckle reduction can be achieved by averaging the magnitudes of A-lines corresponding to the same transverse locations. With both experimental and analytic approaches, we demonstrated that this averaging method does not lead to a substantial loss in spatial resolution. We developed two different imaging systems for performing Angle-Resolved OCT. With the first system, angular data was acquired simultaneously; with the second, it was acquired sequentially. The first system had superior speckle-reduction capabilities but image quality degraded significantly with small sample movements. The second system allowed for in vivo imaging, as demonstrated with Resolved OCT systems, the speckle-reduced images showed hitherto unprecedented delineation of tissue microstructure.

  5. Comparison: Simulation and Experimental Characterisation of an all-Optical Gain-Clamped Erbium-Doped Fibre Amplifier

    Directory of Open Access Journals (Sweden)

    T. Subramaniam M. A. Mahdi P. Poopalan, and H. Ahmad

    2012-10-01

    Full Text Available This paper presents the GC-EDFA characteristics comparison between the simulated results (using EDFA_Design software and experimental results. The comparisons reveal the usefulness of the software in simulating the behaviour of an all-optical GC-EDFA system. Comparisons are made for values obtained from the system operated at high laser power, in order to highlight the differences between the experimental and simulated values. The main objective for this comparison is to prove the capability of the software in simulating the gain-clamped system. Therefore, the software can be used to test new configurations, aimed at improvising current gain-clamped EDFA performances.Keywords optical, gain-clamping, erbium, fibre amplifier, simulation, experiment

  6. Absolute small-angle measurement based on optical feedback interferometry

    Institute of Scientific and Technical Information of China (English)

    Jingang Zhong; Xianhua Zhang; Zhixiang Ju

    2008-01-01

    We present a simple but effective method for small-angle measurement based on optical feedback inter-ferometry (or laser self-mixing interferometry). The absolute zero angle can be defined at the biggest fringe amplitude point, so this method can also achieve absolute angle measurement. In order to verify the method, we construct an angle measurement system. The Fourier-transform method is used to analysis the interference signal. Rotation angles are experimentally measured with a resolution of 10-6 rad and a measurement range of approximately from -0.0007 to +0.0007 rad.

  7. Angle-of-arrival reception for optical wireless location technology.

    Science.gov (United States)

    Arafa, Ahmed; Dalmiya, Sumant; Klukas, Richard; Holzman, Jonathan F

    2015-03-23

    An optical wireless location (OWL) system is introduced for indoor positioning. The OWL system makes use of a mobile photoreceiver that facilitates triangulation by measuring angle-of-arrival (AOA) bearings from LEDs in an optical beacon grid. The photoreceiver has three photodiodes (PDs), arranged in a corner-cube, to facilitate differential photocurrent sensing of the incident light AOA, by way of azimuthal ϕ and polar θ angles. The AOA error for indoor positioning is characterized empirically. Optical AOA positioning is shown to have a fundamental advantage over known optical received signal strength (RSS) positioning, as AOA estimation is insensitive to power and alignment imbalances of the optical beacon grid. The OWL system is built, and a performance comparison is carried out between optical AOA and RSS positioning. It is shown that optical AOA positioning can achieve a mean 3-D positioning error of only 5 cm. Experimental design and future prospects of optical AOA positioning are discussed.

  8. Numerical aperture characteristics of angle-ended plastic optical fiber

    Science.gov (United States)

    Gao, Cheng; Farrell, Gerard

    2003-03-01

    With the increasing information rates demanded in consumer, automotive and aeronautical applications, a low cost and high performance physical transmission medium is required. Compared with Silica Optical Fiber, Plastic Optical Fiber (POF) offers an economic solution for a range of high-capacity, short-haul applications in industrial and military environments. Recently, a new type of POF, the perfluorinated graded-index plastic optical fiber (PF GI-POF), has been introduced that has low losses and high bandwidth at the communication wavelengths 850 nm and 1300nm. POF is normally terminated perpendicular to the fiber axis. We propose an angle-ended POF, which is terminated at non-perpendicular angles to the fiber axis. The aim of the research is to investigate the numerical aperture (NA) characteristics of angle-ended POF along the major axis of the elliptical endface. A theoretical model indicates that the NA of the angle-ended POF will increase nonlinearly with tilt-angle and the acceptance cone will be deflected with the angle of the deflection increasing nonlinearly with tilt-angle. We present results for the measured NA and the measured deflection angle using the far-field radiation method. Results are presented for 13 angle-ended SI-POF tilt-angles. We also present results for theoretical value of NA and deflection angle as a function of tilt-angle. The agreement between the measured and theoretical value is good up to tilt-angles of about 15 degrees, beyond which deviation occurs.

  9. High-fidelity angle-modulated analog optical link.

    Science.gov (United States)

    Che, Di; Yuan, Feng; Shieh, William

    2016-07-25

    There has long existed a debate over whether analog or digital optical link is more suitable for wireless convergence applications. Digital link achieves the highest fidelity, with the sacrifice of huge bandwidth due to the high resolution of digitization, and large power consumption due to the exhaustive digital data recovery. Analog link avoids these drawbacks, but it inevitably suffers from the SNR degradation. In this paper, we propose the angle modulation for analog optical link, which successfully breaks the SNR ceiling of amplitude modulation, and achieves ultrahigh link fidelity. Using the digital link (CPRI) equivalent bandwidth, angle modulation exhibits around 30-dB SNR advantage over the conventional amplitude modulation. Combined with its high tolerance on link nonlinearity, angle modulation has great potential in the future SNR-hungry analog optical applications.

  10. Anterior ischemic optic neuropathy precipitated by acute primary angle closure

    Directory of Open Access Journals (Sweden)

    Choudhari Nikhil

    2010-01-01

    Full Text Available A 59-year-old man with a history of longstanding systemic hypotension developed asymmetric non-arteritic anterior ischemic optic neuropathy (NAION apparently precipitated by bilateral sequential acute primary angle closure. NAION is very rarely reported in association with raised intraocular pressure. In contrast to optical coherence tomography, the failure of scanning laser polarimetry to detect axonal swelling was another interesting finding. Possible reasoning for these observations is discussed.

  11. Role of Optical Coherence Tomography in Assessing Anterior Chamber Angles

    Science.gov (United States)

    Kochupurakal, Reema Thomas; Jha, Kirti Nath; Rajalakshmi, A.R.; Nagarajan, Swathi; Ezhumalai, G.

    2016-01-01

    Introduction Gonioscopy is the gold standard in assessing anterior chamber angles. However, interobserver variations are common and there is a need for reliable objective method of assessment. Aim To compare the anterior chamber angle by gonioscopy and Spectral Domain Optical Coherence Tomography (SD-OCT) in individuals with shallow anterior chamber. Materials and Methods This comparative observational study was conducted in a rural tertiary multi-speciality teaching hospital. A total of 101 eyes of 54 patients with shallow anterior chamber on slit lamp evaluation were included. Anterior chamber angle was graded by gonioscopy using the shaffer grading system. Angles were also assessed by SD-OCT with Trabecular Iris Angle (TIA) and Angle Opening Distance (AOD). Chi-square test, sensitivity, specificity, positive and negative predictive value to find correlation between OCT parameters and gonioscopy grading. Results Females represented 72.7%. The mean age was 53.93 ±8.24 years and mean anterior chamber depth was 2.47 ± 0.152 mm. Shaffer grade ≤ 2 were identified in 95(94%) superior, 42(41.5%) inferior, 65(64.3%) nasal and 57(56.4%) temporal quadrants. Cut-off values of TIA ≤ 22° and AOD ≤ 290 μm were taken as narrow angles on SD-OCT. TIA of ≤ 22° were found in 88(92.6%) nasal and 87(87%) temporal angles. AOD of ≤ 290 μm was found in 73(76.8%) nasal and 83(83%) temporal quadrants. Sensitivity in detecting narrow angles was 90.7% and 82.2% for TIA and AOD, while specificity was 11.7% and 23.4%, respectively. Conclusion Individuals were found to have narrow angles more with SD-OCT. Sensitivity was high and specificity was low in detecting narrow angles compared to gonioscopy, making it an unreliable tool for screening. PMID:27190851

  12. Imaginary angle fractional Fourier transform and its optical implementation

    Institute of Scientific and Technical Information of China (English)

    华建文; 刘立人; 李国强

    1997-01-01

    The concept of imaginary angle fractional Fourier transform is proposed. Its existence and additive operation are proved. With this concept, FRT is expanded to the optical transform of convex lens outside the range of double focal length and that of concave lens.

  13. View angle dependence of cloud optical thicknesses retrieved by MODIS

    Science.gov (United States)

    Marshak, Alexander; Varnai, Tamas

    2005-01-01

    This study examines whether cloud inhomogeneity influences the view angle dependence of MODIS cloud optical thickness (tau) retrieval results. The degree of cloud inhomogeneity is characterized through the local gradient in 11 microns brightness temperature. The analysis of liquid phase clouds in a one year long global dataset of Collection 4 MODIS data reveals that while optical thickness retrievals give remarkably consistent results for all view directions if clouds are homogeneous, they give much higher tau-values for oblique views than for overhead views if clouds are inhomogeneous and the sun is fairly oblique. For solar zenith angles larger than 55deg, the mean optical thickness retrieved for the most inhomogeneous third of cloudy pixels is more than 30% higher for oblique views than for overhead views. After considering a variety of possible scenarios, the paper concludes that the most likely reason for the increase lies in three-dimensional radiative interactions that are not considered in current, one-dimensional retrieval algorithms. Namely, the radiative effect of cloud sides viewed at oblique angles seems to contribute most to the enhanced tau-values. The results presented here will help understand cloud retrieval uncertainties related to cloud inhomogeneity. They complement the uncertainty estimates that will start accompanying MODIS cloud products in Collection 5 and may eventually help correct for the observed view angle dependent biases.

  14. Large optical field enhancement for nanotips with large opening angles

    CERN Document Server

    Thomas, Sebastian; Lemell, Christoph; Burgdörfer, Joachim; Hommelhoff, Peter

    2014-01-01

    We theoretically investigate optical near-fields at nanometric tips. We systematically study the dependence of field enhancement on the shape, size, and material of the tip. We confirm a strong dependence of the field enhancement factor on the radius of curvature. In addition, we find a remarkably strong increase of field enhancement with increasing opening angle of the nanotips. For gold and tungsten nanotips in the experimentally relevant parameter range (radius of curvature $\\geq 5\\,$nm at 800 nm laser wavelength), we obtain field enhancement factors of up to ${\\sim}35$ (Au) and ${\\sim}12$ (W) for wide opening angles. We confirm this strong dependence on the opening angle for many other materials studying the dependence of the field enhancement at nanotips on the dielectric response function. For dielectrics, the increase in field enhancement is traced back to the electrostatic force of the induced surface charge at the tip shank. For metals, the plasmonic response strongly increases the field enhancement ...

  15. Optical Enhancement of Exoskeleton-Based Estimation of Glenohumeral Angles.

    Science.gov (United States)

    Cortés, Camilo; Unzueta, Luis; de Los Reyes-Guzmán, Ana; Ruiz, Oscar E; Flórez, Julián

    2016-01-01

    In Robot-Assisted Rehabilitation (RAR) the accurate estimation of the patient limb joint angles is critical for assessing therapy efficacy. In RAR, the use of classic motion capture systems (MOCAPs) (e.g., optical and electromagnetic) to estimate the Glenohumeral (GH) joint angles is hindered by the exoskeleton body, which causes occlusions and magnetic disturbances. Moreover, the exoskeleton posture does not accurately reflect limb posture, as their kinematic models differ. To address the said limitations in posture estimation, we propose installing the cameras of an optical marker-based MOCAP in the rehabilitation exoskeleton. Then, the GH joint angles are estimated by combining the estimated marker poses and exoskeleton Forward Kinematics. Such hybrid system prevents problems related to marker occlusions, reduced camera detection volume, and imprecise joint angle estimation due to the kinematic mismatch of the patient and exoskeleton models. This paper presents the formulation, simulation, and accuracy quantification of the proposed method with simulated human movements. In addition, a sensitivity analysis of the method accuracy to marker position estimation errors, due to system calibration errors and marker drifts, has been carried out. The results show that, even with significant errors in the marker position estimation, method accuracy is adequate for RAR.

  16. Large optical field enhancement for nanotips with large opening angles

    Science.gov (United States)

    Thomas, Sebastian; Wachter, Georg; Lemell, Christoph; Burgdörfer, Joachim; Hommelhoff, Peter

    2015-06-01

    We theoretically investigate the dependence of the enhancement of optical near-fields at nanometric tips on the shape, size, and material of the tip. We confirm the strong dependence of the field enhancement factor on the radius of curvature. In addition, we find a surprisingly strong increase of field enhancement with increasing opening angle of the nanotips. For gold and tungsten nanotips in the experimentally relevant parameter range (radius of curvature ≥slant 5 nm at 800 nm laser wavelength), we obtain field enhancement factors of up to ∼ 35 for Au and ∼ 12 for W for large opening angles. We confirm this strong dependence on the opening angle for many other materials featuring a wide variety in their dielectric response. For dielectrics, the opening angle dependence is traced back to the electrostatic force of the induced surface charge at the tip shank. For metals, the plasmonic response strongly increases the field enhancement and shifts the maximum field enhancement to smaller opening angles.

  17. IR Optics Measurement with Linear Coupling's Action-Angle Parameterization

    CERN Document Server

    Luo, Yun; Pilat, Fulvia Caterina; Satogata, Todd; Trbojevic, Dejan

    2005-01-01

    The interaction region (IP) optics are measured with the two DX/BPMs close to the IPs at the Relativistic Heavy Ion Collider (RHIC). The beta functions at IP are measured with the two eigenmodes' phase advances between the two BPMs. And the beta waists are also determined through the beta functions at the two BPMs. The coupling parameters at the IPs are also given through the linear coupling's action-angle parameterization. All the experimental data are taken during the driving oscillations with the AC dipole. The methods to do these measurements are discussed. And the measurement results during the beta*

  18. Gain variation induced by power transient in thulium-doped fiber amplifier at 2 μm and its reduction by optical gain clamping technique

    Science.gov (United States)

    Khamis, M. A.; Ennser, K.

    2017-02-01

    This paper investigates the dynamic behavior of a thulium doped fiber amplifier (TDFA) operating in the 2 μm region for reconfigurable wavelength division multiplexing (WDM) systems. We show deleterious channel power fluctuations may be generated by input power variation at the amplifier and we propose the use of an optical gain-clamping technique. The investigated system consists of 20 channels with -4 dBm total input power. Our findings revealed that the effects of power transients due to channel reconfigurations are significantly reduced by a lasing feedback signal. Simulation results show that a power excursion of 4.3 dB is produced after dropping 19 channels when the amplifier gain is unclamped and only 0.0062 dB when the amplifier gain is clamped. The dynamics of GC-TDFA are mainly influenced by the value of the pump power factor and thus the laser signal achieves a stronger stabilization condition with increasing pump power factor. Hence, optical gain clamping is a simple and robust technique to control the power transient in the thulium-doped fiber amplifier of WDM systems at 2 μm.

  19. Chemical potential of water from measurements of optic axial angle of zeolites

    Science.gov (United States)

    Donald, Eberlein G.; Christ, C.L.

    1968-01-01

    Values of the uncorrected optic axial angle (2H??) of a crystal of the calcium zeolite stellerite (CaAl2Si7O 18 ?? 7H2O) immersed in calcium chloride solutions of known activity of water (aw) are directly proportional to log aw. A general relationship between the chemical potential of water in the crystal and the optic axial angle is obeyed.

  20. THE BEHAVIOR OF THE PITCH ANGLE OF SPIRAL ARMS DEPENDING ON OPTICAL WAVELENGTH

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-García, Eric E.; Puerari, Ivânio; Rosales-Ortega, F. F.; Luna, A. [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla, Pue. (Mexico); González-Lópezlira, Rosa A. [Centro de Radioastronomía y Astrofísica, UNAM, Campus Morelia, Michoacán, México, C.P. 58089 (Mexico); Fuentes-Carrera, Isaura, E-mail: ericmartinez@inaoep.mx [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, U. P. Adolfo López Mateos, Zacatenco, 07730 México, D.F. (Mexico)

    2014-09-20

    Based on integral field spectroscopy data from the CALIFA survey, we investigate the possible dependence of spiral arm pitch angle with optical wavelength. For three of the five studied objects, the pitch angle gradually increases at longer wavelengths. This is not the case for two objects where the pitch angle remains constant. This result is confirmed by the analysis of SDSS data. We discuss the possible physical mechanisms to explain this phenomenon, as well as the implications of the results.

  1. To clamp or not to clamp late?

    Directory of Open Access Journals (Sweden)

    Nicoletta Iacovidou

    2013-04-01

    Full Text Available When resuscitating a neonate, one encounters controversial issues and a great deal of confusion. These issues include the question as to when should the umbilical cord be clamped. Clamping and cutting the umbilical cord at birth is the oldest intervention in humans. Even though many aspects of the timing for cord clamping have been clarified, some questions still remain unanswered. If delayed cord clamping is to become a standard approach which timing is the optimal? And depending on the mode of delivery should timing be the same or different for normal vaginal delivery or for caesarean section? What about  the compromised neonate, or the very preterm one? We have more questions than answers. More randomized controlled studies are needed in normal and pathologic neonates, in order to address these questions, before we practice delayed cord clamping with safety for the babies and the mothers.

  2. A lab-on-a-chip for hypoxic patch clamp measurements combined with optical tweezers and spectroscopy- first investigations of single biological cells.

    Science.gov (United States)

    Alrifaiy, Ahmed; Borg, Johan; Lindahl, Olof A; Ramser, Kerstin

    2015-04-18

    The response and the reaction of the brain system to hypoxia is a vital research subject that requires special instrumentation. With this research subject in focus, a new multifunctional lab-on-a-chip (LOC) system with control over the oxygen content for studies on biological cells was developed. The chip was designed to incorporate the patch clamp technique, optical tweezers and absorption spectroscopy. The performance of the LOC was tested by a series of experiments. The oxygen content within the channels of the LOC was monitored by an oxygen sensor and verified by simultaneously studying the oxygenation state of chicken red blood cells (RBCs) with absorption spectra. The chicken RBCs were manipulated optically and steered in three dimensions towards a patch-clamp micropipette in a closed microfluidic channel. The oxygen level within the channels could be changed from a normoxic value of 18% O 2 to an anoxic value of 0.0-0.5% O 2. A time series of 3 experiments were performed, showing that the spectral transfer from the oxygenated to the deoxygenated state occurred after about 227 ± 1 s and a fully developed deoxygenated spectrum was observed after 298 ± 1 s, a mean value of 3 experiments. The tightness of the chamber to oxygen diffusion was verified by stopping the flow into the channel system while continuously recording absorption spectra showing an unchanged deoxygenated state during 5400 ± 2 s. A transfer of the oxygenated absorption spectra was achieved after 426 ± 1 s when exposing the cell to normoxic buffer. This showed the long time viability of the investigated cells. Successful patching and sealing were established on a trapped RBC and the whole-cell access (Ra) and membrane (Rm) resistances were measured to be 5.033 ± 0.412 M Ω and 889.7 ± 1.74 M Ω respectively.

  3. Interferometry of a reflective axicon surface with a small cone angle using an optical inner surface

    Science.gov (United States)

    Gao, Huimin; Zhang, Xiaodong; Fang, Fengzhou

    2017-09-01

    Reflective axicons, widely used in optical alignment and Bessel-Gauss beam generation, require a highly accurate cone angle and surface metrology. However, current methods focus on the cone angle measurement and it is still difficult to measure the surface of a reflective axicon with a small cone angle. An interferometer measurement method using an optical inner surface is proposed to obtain the surface and cone angle simultaneously. The optical axis of the axicon and the optical inner surface should align together and be parallel to the beam light from the interferometer. The interference fringe would be obtained by the optical system consisting of the axicon and the optical inner surface. The theoretical model is established and analyzed through ray tracing theory, and is verified by optical simulation software. Fabrication errors in the axicon and the inner surface, and misalignment of the measurement setup are investigated systematically and separated in the measurement process. In the experiments, the reflective axicon with a cone angle of about 90° was measured by the proposed method, the results of which show good agreement with a stylus profiler (Taylor-Hobson PGI 3D) in cone angle trend and generatrix error. Experimental results prove the feasibility of the proposed method. This economical and effective method can be widely used with all types of reflective axicons, and it can obtain the surface error map of the axicon as well as the inner cylinder at the same time. The uncertainty and resolution of the proposed method is based on the performance of the interferometer. The uncertainty of alignment angle errors is less than 10-10 rad; the lateral resolution is 53.8 µm.

  4. Optical trapping of nanoparticles by full solid-angle focusing

    CERN Document Server

    Salakhutdinov, Vsevolod; Carbone, Luigi; Giacobino, Elisabeth; Bramati, Alberto; Leuchs, Gerd

    2015-01-01

    We propose and implement a dipole-trap for nanoparticles that is based on focusing from the full solid angle with a deep parabolic mirror. The key aspect is the generation of a linear-dipole mode. For such a mode, our calculations predict a trapping potential that is deeper and tighter than the potential obtainable with microscope objectives. We demonstrate the trapping of dot-in-rod nanoparticles. From the detected fluorescence photons we obtain intensity correlation functions of second order with $g^{(2)}(0)< 0.5$, suggesting the trapping of a single quantum emitter.

  5. Photovoltaic panel clamp

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Malcolm P.; Mittan, Margaret Birmingham; Miros, Robert H. J.; Stancel, Robert

    2013-03-19

    A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

  6. Photovoltaic panel clamp

    Science.gov (United States)

    Mittan, Margaret Birmingham; Miros, Robert H. J.; Brown, Malcolm P.; Stancel, Robert

    2012-06-05

    A photovoltaic panel clamp includes an upper and lower section. The interface between the assembled clamp halves and the module edge is filled by a flexible gasket material, such as EPDM rubber. The gasket preferably has small, finger like protrusions that allow for easy insertion onto the module edge while being reversed makes it more difficult to remove them from the module once installed. The clamp includes mounting posts or an integral axle to engage a bracket. The clamp also may include a locking tongue to secure the clamp to a bracket.

  7. Unilateral Optic Neuropathy and Acute Angle-Closure Glaucoma following Snake Envenomation

    Directory of Open Access Journals (Sweden)

    Osman Okan Olcaysu

    2015-01-01

    Full Text Available Purpose. We aimed to describe a unique case in which a patient developed unilateral optic neuritis and angle-closure glaucoma as a result of snake envenomation. Case Report. Approximately 18 hours after envenomation, a 67-year-old female patient described visual impairment and severe pain in her left eye (LE. The patient’s best corrected visual acuity was 10/10 in the RE and hand motion in the LE. Cranial magnetic resonance imaging showed signs of neuropathy in the left optic nerve. In the LE, corneal haziness, closure of the iridocorneal angle, and mild mydriasis were observed and pupillary light reflex was absent. Intraocular pressure was 25 mmHg and 57 mmHg in the RE and LE, respectively. The patient was diagnosed with acute angle-closure glaucoma in the LE. Optic neuropathy was treated with intravenous pulse methylprednisolone. Left intraocular pressure was within normal range starting on the fourth day. One month after the incident, there was no sign of optic neuropathy; relative afferent pupillary defect and optic nerve swelling disappeared. Conclusions. Patients with severe headache and visual loss after snake envenomation must be carefully examined for possible optic neuropathy and angle-closure glaucoma. Early diagnosis and treatment of these cases are necessary to prevent permanent damage to optic nerves.

  8. Glancing angle deposition for production of optical components in UV region

    Science.gov (United States)

    Tolenis, Tomas; GrinevičiÅ«tÄ--, Lina; Buzelis, Rytis; Petronis, Laurynas; Drazdys, Ramutis

    2016-09-01

    Technological developments in laser technology require advancements in optical components. Such demand is particularly important in UV spectral region. Antireflection coatings (AR) and waveplates as a widely used optical elements were produced based on glancing angle deposition (GLAD) method. Superior optical performance was measured for AR thin films. Broadband and broad-angle antireflection coatings were manufactured by using multilayer system when changing the refractive index profile by varying the porosity of material. SiO2, Al2O3 and LaF3 materials were used for formation of waveplates for UV region. An investigation of optical and resistant performance were conducted. All materials showed optical losses at the wavelength of 355 nm. Possible technological solutions are presented and investigated.

  9. Quantum correlations in optical angle-orbital angular momentum variables.

    Science.gov (United States)

    Leach, Jonathan; Jack, Barry; Romero, Jacqui; Jha, Anand K; Yao, Alison M; Franke-Arnold, Sonja; Ireland, David G; Boyd, Robert W; Barnett, Stephen M; Padgett, Miles J

    2010-08-06

    Entanglement of the properties of two separated particles constitutes a fundamental signature of quantum mechanics and is a key resource for quantum information science. We demonstrate strong Einstein, Podolsky, and Rosen correlations between the angular position and orbital angular momentum of two photons created by the nonlinear optical process of spontaneous parametric down-conversion. The discrete nature of orbital angular momentum and the continuous but periodic nature of angular position give rise to a special sort of entanglement between these two variables. The resulting correlations are found to be an order of magnitude stronger than those allowed by the uncertainty principle for independent (nonentangled) particles. Our results suggest that angular position and orbital angular momentum may find important applications in quantum information science.

  10. Measurement of the Optical Rotation Angle Using a Rotating-Wave-Plate Stokes Polarimeter

    Directory of Open Access Journals (Sweden)

    Chang C.C.

    2010-06-01

    Full Text Available A polarimeter based on Stokes-Mueller formalism and rotating-wave-plate Stokes polarimeter is successfully developed to measure the optical rotation angle in a chiral medium. The average relative error in the measured rotation angles of glucose solutions with concentrations ranging from 0 to 1.2g/dl is determined to be 3.78%. The correlation coefficient between the measured rotation angle and the glucose concentration is found to be 0.9995, while the standard deviation is just 0.00376 degrees. From the sol-gel materials containing C17H17ClO6 with concentrations ranging from 0 to 0.0665g/ml, the average relative error in the measured rotation angles is determined to be 3.63%. Consequently, the developed system is evaluated with a precision of 5.4% approximately in rotation angle measurement.

  11. Radial wedge flange clamp

    Science.gov (United States)

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  12. A controllable viewing angle LCD with an optically isotropic liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Su; Lim, Young Jin; Yoon, Sukin; Kang, Shin-Woong; Lee, Seung Hee [Department of BIN Fusion Technology and Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kim, Miyoung [Korea Electronics Technology Institute, Jeonju, Jeonbuk 561-844 (Korea, Republic of); Wu, Shin-Tson, E-mail: lsh1@chonbuk.ac.k, E-mail: swu@creol.ucf.ed [College of Optics and Photonics, University of Central Florida, Orlando, FL 32816 (United States)

    2010-04-14

    An optically isotropic liquid crystal (LC) such as a blue phase LC or an optically isotropic nano-structured LC exhibits a very wide viewing angle because the induced birefringence is along the in-plane electric field. Utilizing such a material, we propose a liquid crystal display (LCD) whose viewing angle can be switched from wide view to narrow view using only one panel. In the device, each pixel is divided into two parts: a major pixel and a sub-pixel. The main pixels display the images while the sub-pixels control the viewing angle. In the main pixels, birefringence is induced by horizontal electric fields through inter-digital electrodes leading to a wide viewing angle, while in the sub-pixels, birefringence is induced by the vertical electric field so that phase retardation occurs only at oblique angles. As a result, the dark state (or contrast ratio) of the entire pixel can be controlled by the voltage of the sub-pixels. Such a switchable viewing angle LCD is attractive for protecting personal privacy.

  13. Pit-like changes of the optic nerve head in open-angle glaucoma.

    Science.gov (United States)

    Radius, R. L.; Maumenee, A. E.; Green, W. R.

    1978-01-01

    Six patients with open-angle glaucoma and acquired pit-like changes in the optic nerve head are presented. In 1 patient evolution of the pit-like defect is documented. In all 6 patients progression of associated visual field deficits is described. It is suggested that such pit-like changes in selected patients with glaucoma may not represent congenital lesions but rather local, progressive nerve head disease, occurring particularly in response to raised intraocular pressure. The management of patients with optic nerve head pitting and the pathogenesis of glaucomatous optic neuropathy are discussed with respect to this observation. Images PMID:666988

  14. Study of optical techniques for the Ames unitary wind tunnels. Part 3: Angle of attack

    Science.gov (United States)

    Lee, George

    1992-01-01

    A review of optical sensors that are capable of accurate angle of attack measurements in wind tunnels was conducted. These include sensors being used or being developed at NASA Ames and Langley Research Centers, Boeing Airplane Company, McDonald Aircraft Company, Arnold Engineering Development Center, National Aerospace Laboratory of the Netherlands, National Research Council of Canada, and the Royal Aircraft Establishment of England. Some commercial sensors that may be applicable to accurate angle measurements were also reviewed. It was found that the optical sensor systems were based on interferometers, polarized light detector, linear or area photodiode cameras, position sensing photodetectors, and laser scanners. Several of the optical sensors can meet the requirements of the Ames Unitary Plan Wind Tunnel. Two of these, the Boeing interferometer and the Complere lateral effect photodiode sensors are being developed for the Ames Unitary Plan Wind Tunnel.

  15. Plasmonic nanowires arranged in Fibonacci number chain: Excitation angle-dependent optical properties

    Directory of Open Access Journals (Sweden)

    Mohit Raghuwanshi

    2013-02-01

    Full Text Available Herein we numerically study the excitation angle-dependant far-field and near-field optical properties of vertical plasmonic nanowires arranged in an unconventional linear geometry: Fibonacci number chain. The first five numbers in the Fibonacci series (1, 1, 2, 3, 5 were mapped to the size of gold nanowires, and arranged in a linear chain to study their optical interactions, and compared them to conventional chain of vertical gold nanowires. By harnessing the radiative and evanescent coupling regimes in the geometry, we found a systematic variation in the far-field extinction and near-field confinement in the geometries. Our simulation studies revealed enhanced backscattered intensity in the far-field radiation pattern at excitation angles along the chain-length of Fibonacci geometry, which was otherwise absent for conventional chain of plasmonic nanowires. Such angular reconfiguration of optical fields in unconventional linear geometries can be harnessed for tunable on-chip plasmonics.

  16. Broadband angle- and permittivity-insensitive nondispersive optical activity based on chiral metamaterials

    CERN Document Server

    Song, Kun; Su, Zhaoxian; Ding, Changlin; Liu, Yahong; Luo, Chunrong; Zhao, Xiaopeng; Bhattarai, Khagendra; Zhou, Jiangfeng

    2016-01-01

    Because of the strong inherent resonances, the giant optical activity obtained via chiral metamaterials generally suffers from high dispersion, which has been a big stumbling block to broadband applications. In this paper, we propose a type of chiral metamaterial consisting of interconnected metal helix structures with four-fold symmetry, which exhibits nonresonant Drude-like response and can therefore avoid the highly dispersive optical activity resulting from resonances. It shows that the well-designed chiral metamaterial can achieve nondispersive and pure optical activity with high transmittance in a broadband frequency range. And the optical activity of multi-layer chiral metamaterials is proportional to the layer numbers of single-layer chiral metamaterial. Most remarkably, the broadband behaviors of nondispersive optical activity and high transmission are insensitive to the incident angles of electromagnetic waves and permittivity of dielectric substrate, thereby enabling more flexibility in polarizatio...

  17. Measurement of z-axis deviation angle of electro-optic crystal by conoscopic interference

    Science.gov (United States)

    Li, Dong; Liu, Yong; Liu, Xu; Jiang, Hongzhen; Zheng, Fanglan

    2016-09-01

    Properties of plasma electrode pockels cell is directly affected by the Z-axis deviation angle of the electro-optic crystal. Therefore, high precision measurement of the Z-axis deviation angle is indispensable. By using conoscopic interference technique, a measurement system for Z-axis deviation angle of electro-optic crystal is introduced. The principle of conoscopic interference method is described in detail, and a series of techniques are implied in this measurement system to improve the accuracy. High-precision positioning method of the crystal based on Michelson interference is proposed to determine the normal consistency of crystal, which can ensure the high positioning repeatability of crystal in the measurement process. The positioning comparison experiment of the crystal shows that the standard deviation of our method is less than 1pixel, which is much better than the traditional method (nearly 4pixels). Moreover, melatope extraction algorithm of optical axis based on image matching technique is proposed to ensure the melatope can be extracted in high precision. Calibration method of the normal of transmission surface of crystal is also proposed. The experiment results show that the PV and rms of Z-axis deviation angle is less than 0.05mrad and 0.02mrad, respectively. The repeatability accuracy is less than 0.01mrad.

  18. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting.

    Science.gov (United States)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-09-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed.

  19. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    Science.gov (United States)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-09-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed.

  20. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    Science.gov (United States)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-01-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed. PMID:27582317

  1. Glancing angle deposited Al-doped ZnO nanostructures with different structural and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, A., E-mail: yildizab@gmail.com [Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, AR 72204 (United States); Department of Energy Systems Engineering, Faculty of Engineering and Natural Sciences, Yıldırım Beyazıt University, Ankara (Turkey); Cansizoglu, H. [Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, AR 72204 (United States); Turkoz, M. [Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, AR 72204 (United States); Department of Electrical-Electronic Engineering, Faculty of Engineering, University of Karabuk, Karabuk (Turkey); Abdulrahman, R.; Al-Hilo, Alaa; Cansizoglu, M.F.; Demirkan, T.M.; Karabacak, T. [Department of Physics and Astronomy, University of Arkansas at Little Rock, Little Rock, AR 72204 (United States)

    2015-08-31

    Al-doped ZnO (AZO) nanostructure arrays with different shapes (tilted rods, vertical rods, spirals, and zigzags) were fabricated by utilizing glancing angle deposition (GLAD) technique in a DC sputter growth unit at room temperature. During GLAD, all the samples were tilted at an oblique angle of about 90° with respect to incoming flux direction. In order to vary the shapes of nanostructures, each sample was rotated at different speeds around the substrate normal axis. Rotation speed did not only affect the shape but also changed the microstructural and optical properties of GLAD AZO nanostructures. The experimental results reveal that GLAD AZO nanostructures of different shapes each have unique morphological, crystal structure, mechanical, and optical properties determined by scanning electron microscopy, X-ray diffraction, transmission, and reflectance measurements. Vertical nanorods display the largest grain size, minimum strain, lowest defect density, and highest optical transmittance compared to the other shapes. Growth dynamics of GLAD has been discussed to explain the dependence of structural and optical properties of nanostructures on the substrate rotation speed. - Highlights: • Al-doped ZnO (AZO) nanostructures with different shapes were fabricated. • They have unique morphological, crystal structure, and optical properties. • Vertical AZO nanorods show an enhanced optical transmittance.

  2. Anterior segment changes after pharmacologic mydriasis using Pentacam and optical coherence tomography in angle closure suspects

    Directory of Open Access Journals (Sweden)

    Jing-Min Guo

    2015-10-01

    Full Text Available AIM:To compare the dynamic changes of anterior segment parameters especially iris morphology induced by pharmacologic mydriasis between angle closure suspects and normal controls.METHODS:The study group comprised 19 eyes of 19 angle closure suspects and 19 eyes of 19 age- and sex-matched normal open-angle eyes. Pentacam and optical coherence tomography measurements before and 30min after instillation of compound tropicamide eye drop were performed and compared. Biometric evaluations of iris tomography and anterior chamber angle were estimated by a customized image-processing software.RESULTS:Baseline axial length, iris cross sectional area and volume did not differ significantly between angle closure suspects and normal controls. Angle closure suspects had smaller pupil size, narrower anterior segment dimension and axial length, thinner iris with greater curve in comparison with normal controls. Pharmacologic mydriasis led to significant increments in iris thickness at 750 μm, anterior chamber depth and volume, whereas significant decrements in iris curve, cross sectional area and volume in both groups. Angle opening distance at 500 μm was increased significantly in normal controls (from 0.465±0.115 mm to 0.539±0.167 mm, P=0.009, but not in angle closure suspects (from 0.125±0.100 mm to 0.145±0.131 mm, P=0.326. Iris volume change per millimeter of pupil dilation (△IV/△PD decreased significantly less in angle closure suspects than normal controls (-2.47±1.33 mm2 vs -3.63±1.58 mm2, P=0.019. Linear regression analysis showed that the change of angle opening distance at 500 μm was associated most with the change of central anterior chamber depth (β=0.841, P=0.002 and △IV/△PD (β=0.028, P=0.002, followed by gender (β=0.062, P=0.032.CONCLUSION:Smaller iris volume decrement per millimeter of pupil dilation is related significantly with the less anterior angle opening in angle closure suspects after pharmacologic mydriasis. Dynamic

  3. Step angles to reduce the north-finding error caused by rate random walk with fiber optic gyroscope.

    Science.gov (United States)

    Wang, Qin; Xie, Jun; Yang, Chuanchuan; He, Changhong; Wang, Xinyue; Wang, Ziyu

    2015-10-20

    We study the relationship between the step angles and the accuracy of north finding with fiber optic gyroscopes. A north-finding method with optimized step angles is proposed to reduce the errors caused by rate random walk (RRW). Based on this method, the errors caused by both angle random walk and RRW are reduced by increasing the number of positions. For when the number of positions is even, we proposed a north-finding method with symmetric step angles that can reduce the error caused by RRW and is not affected by the azimuth angles. Experimental results show that, compared with the traditional north-finding method, the proposed methods with the optimized step angles and the symmetric step angles can reduce the north-finding errors by 67.5% and 62.5%, respectively. The method with symmetric step angles is not affected by the azimuth angles and can offer consistent high accuracy for any azimuth angles.

  4. Agreement of angle closure assessments between gonioscopy, anterior segment optical coherence tomography and spectral domain optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    Elton; Lik; Tong; Tay; Vernon; Khet; Yau; Yong; Boon; Ang; Lim; Stelson; Sia; Elizabeth; Poh; Ying; Wong; Leonard; Wei; Leon; Yip

    2015-01-01

    AIM: To determine angle closure agreements between gonioscopy and anterior segment optical coherence tomography(AS-OCT), as well as gonioscopy and spectral domain OCT(SD-OCT). A secondary objective was to quantify inter-observer agreements of AS-OCT and SD-OCT assessments.METHODS: Seventeen consecutive subjects(33 eyes)were recruited from the study hospital’s Glaucoma clinic.Gonioscopy was performed by a glaucomatologist masked to OCT results. OCT images were read independently by 2 other glaucomatologists masked to gonioscopy findings as well as each other’s analyses of OCT images.RESULTS: Totally 84.8% and 45.5% of scleral spurs were visualized in AS-OCT and SD-OCT images respectively(P <0.01). The agreement for angle closure between AS-OCT and gonioscopy was fair at k =0.31(95% confidence interval, CI: 0.03-0.59) and k =0.35(95%CI: 0.07-0.63) for reader 1 and 2 respectively. The agreement for angle closure between SD-OCT and gonioscopy was fair at k =0.21(95% CI: 0.07-0.49) and slight at k =0.17(95% CI: 0.08-0.42) for reader 1 and 2 respectively. The inter-reader agreement for angle closure in AS-OCT images was moderate at 0.51(95% CI: 0.13-0.88). The inter-reader agreement for angle closure in SD-OCT images was slight at 0.18(95% CI: 0.08-0.45).CONCLUSION: Significant proportion of scleral spurs were not visualised with SD-OCT imaging resulting in weaker inter-reader agreements. Identifying other angle landmarks in SD-OCT images will allow more consistent angle closure assessments. Gonioscopy and OCT imaging do not always agree in angle closure assessments but have their own advantages, and should be used together and not exclusively.

  5. Growth direction of oblique angle electron beam deposited silicon monoxide thin films identified by optical second-harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Vejling Andersen, Søren; Lund Trolle, Mads; Pedersen, Kjeld [Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, DK-9220 Aalborg Øst (Denmark)

    2013-12-02

    Oblique angle deposited (OAD) silicon monoxide (SiO) thin films forming tilted columnar structures have been characterized by second-harmonic generation. It was found that OAD SiO leads to a rotationally anisotropic second-harmonic response, depending on the optical angle of incidence. A model for the observed dependence of the second-harmonic signal on optical angle of incidence allows extraction of the growth direction of OAD films. The optically determined growth directions show convincing agreement with cross-sectional scanning electron microscopy images. In addition to a powerful characterization tool, these results demonstrate the possibilities for designing nonlinear optical devices through SiO OAD.

  6. Reproducibility of Scleral Spur Identification and Angle Measurements Using Fourier Domain Anterior Segment Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Ricardo J. Cumba

    2012-01-01

    Full Text Available Purpose. To evaluate intraobserver and interobserver agreement in locating the scleral spur landmark (SSL and anterior chamber angle measurements obtained using Fourier Domain Anterior Segment Optical Coherence Tomography (ASOCT images. Methods. Two independent, masked observers (SR and AZC identified SSLs on ASOCT images from 31 eyes with open and nonopen angles. A third independent reader, NPB, adjudicated SSL placement if identifications differed by more than 80 μm. Nine months later, SR reidentified SSLs. Intraobserver and interobserver agreement in SSL placement, trabecular-iris space area (TISA750, and angle opening distance (AOD750 were calculated. Results. In 84% of quadrants, SR’s SSL placements during 2 sessions were within 80 μm in both the X- and Y-axes, and in 77% of quadrants, SR and AZC were within 80 μm in both axes. In adjudicated images, 90% of all quadrants were within 80 μm, 88% in nonopen-angle eyes, and 92% in open-angle eyes. The intraobserver and interobserver correlation coefficients (with and without adjudication were above 0.9 for TISA750 and AOD750 for all quadrants. Conclusions. Reproducible identification of the SSL from images obtained with FD-ASOCT is possible. The ability to identify the SSL allows reproducible measurement of the anterior chamber angle using TISA750 and AOD750.

  7. Design and optimization of broadband wide-angle antireflection structures for binary diffractive optics.

    Science.gov (United States)

    Chang, Chih-Hao; Waller, Laura; Barbastathis, George

    2010-04-01

    We propose a class of antireflecting structures that can effectively suppress reflections for binary diffractive optics. In this structure, multiple periodic thin films with gradually varying refractive indices are used to shift all reflected diffraction to the transmitted orders. The structure is optimized to operate over broad bands and wide angles using rigorous coupled-wave analysis and genetic algorithms. We validated the structure numerically using finite-difference time-domain methods. The proposed structure may lead to more efficient diffractive devices for applications in thin-film photovoltaic, waveguide coupler, and holographic optical elements.

  8. Lamina cribrosa defects and optic disc morphology in primary open angle glaucoma with high myopia.

    Directory of Open Access Journals (Sweden)

    Yugo Kimura

    Full Text Available PURPOSE: To investigate whether lamina cribrosa (LC defects are associated with optic disc morphology in primary open angle glaucoma (POAG eyes with high myopia. METHODS: A total of 129 POAG patients and 55 age-matched control subjects with high myopia were evaluated. Three-dimensional scan images obtained by swept source optical coherence tomography were used to detect LC defects. Radial B-scans and infrared images obtained by spectral domain optical coherence tomography were used to measure β-peripapillary atrophy (PPA lengths with and without Bruch's membrane (BM (temporal, nasal, superior, and inferior, tilt angle (vertical and horizontal, and disc diameter (transverse and longitudinal. Peripapillary intrachoroidal cavitations (PICCs, disc area, ovality index, and cyclotorsion of the optic disc were analyzed as well. RESULTS: LC defects were found in 70 of 129 (54.2% POAG eyes and 1 of 55 (1.8% control eyes (P < 0.001. Age, sex, spherical equivalent, axial length, intraocular pressure, and central corneal thickness were not significantly different among POAG eyes with LC defects, POAG eyes without LC defects, and control eyes. Temporal PPA lengths without BM in all three groups correlated significantly with vertical and horizontal tilt angles, although no PPA length with BM correlated significantly with any tilt angle. PICCs were detected more frequently in POAG eyes with LC defects than those without LC defects (P = 0.01 and control eyes (P = 0.02. POAG eyes with LC defects showed a smaller ovality index (P = 0.004, longer temporal PPA without BM (P < 0.001, and larger vertical/horizontal tilt angles (vertical, P < 0.001; horizontal, P = 0.01, and transverse diameter (P = 0.01. In multivariate analysis for the presence of LC defects, presence of POAG (P < 0.001 and vertical tilt angle (P < 0.001 were identified as significant. CONCLUSIONS: The presence of LC defects was associated with myopic optic disc morphology in POAG eyes with high

  9. Full optical characterization of autostereoscopic 3D displays using local viewing angle and imaging measurements

    Science.gov (United States)

    Boher, Pierre; Leroux, Thierry; Bignon, Thibault; Collomb-Patton, Véronique

    2012-03-01

    Two commercial auto-stereoscopic 3D displays are characterized a using Fourier optics viewing angle system and an imaging video-luminance-meter. One display has a fixed emissive configuration and the other adapts its emission to the observer position using head tracking. For a fixed emissive condition, three viewing angle measurements are performed at three positions (center, right and left). Qualified monocular and binocular viewing spaces in front of the display are deduced as well as the best working distance. The imaging system is then positioned at this working distance and crosstalk homogeneity on the entire surface of the display is measured. We show that the crosstalk is generally not optimized on all the surface of the display. Display aspect simulation using viewing angle measurements allows understanding better the origin of those crosstalk variations. Local imperfections like scratches and marks generally increase drastically the crosstalk, demonstrating that cleanliness requirements for this type of display are quite critical.

  10. Mapping 3D fiber orientation in tissue using dual-angle optical polarization tractography.

    Science.gov (United States)

    Wang, Y; Ravanfar, M; Zhang, K; Duan, D; Yao, G

    2016-10-01

    Optical polarization tractography (OPT) has recently been applied to map fiber organization in the heart, skeletal muscle, and arterial vessel wall with high resolution. The fiber orientation measured in OPT represents the 2D projected fiber angle in a plane that is perpendicular to the incident light. We report here a dual-angle extension of the OPT technology to measure the actual 3D fiber orientation in tissue. This method was first verified by imaging the murine extensor digitorum muscle placed at various known orientations in space. The accuracy of the method was further studied by analyzing the 3D fiber orientation of the mouse tibialis anterior muscle. Finally we showed that dual-angle OPT successfully revealed the unique 3D "arcade" fiber structure in the bovine articular cartilage.

  11. Angle of Arrival Detection Through Analysis of Optical Fiber Intensity Patterns

    Science.gov (United States)

    1989-12-01

    P~atterson AFB3 011, December 19-18. * Hecht , Eugene . Optics. Reading NIA: Addison-Wesleyv Pn bushing’ (𔃺ouIipa1uy 1987. 5. Hl~ol, Herb~ert B. Anglf...DTIC ANGLE OF ARRIV AL DETECTION FECTE FIROIGH ANALYSIS OF OPTICA \\L FIBER INTLNSITY~P \\fTERNS DEC 141989 THESIS C-4 John .Xallace Welker Captain

  12. High diffraction efficiency of three-layer diffractive optics designed for wide temperature range and large incident angle.

    Science.gov (United States)

    Mao, Shan; Cui, Qingfeng; Piao, Mingxu; Zhao, Lidong

    2016-05-01

    A mathematical model of diffraction efficiency and polychromatic integral diffraction efficiency affected by environment temperature change and incident angle for three-layer diffractive optics with different dispersion materials is put forward, and its effects are analyzed. Taking optical materials N-FK5 and N-SF1 as the substrates of multilayer diffractive optics, the effect on diffraction efficiency and polychromatic integral diffraction efficiency with intermediate materials POLYCARB is analyzed with environment temperature change as well as incident angle. Therefore, three-layer diffractive optics can be applied in more wide environmental temperature ranges and larger incident angles for refractive-diffractive hybrid optical systems, which can obtain better image quality. Analysis results can be used to guide the hybrid imaging optical system design for optical engineers.

  13. Analysis of Contact Characteristic of Overhead Line and Suspension Clamp

    Directory of Open Access Journals (Sweden)

    Zhao Xinze

    2013-01-01

    Full Text Available In this paper, a LGJ150/25 type ACSR transmission line and a CGU-3 type suspension clamp are taken as research objects. A contact model of the conductor and the clamp was established by using finite element method. The effects of sag angle of the conductor, holding force and tension force in section are analyzed. The results showed that the contact area in the middle of the clamp is of belt-like type. The extreme values of tress were observed on the edge of the contact area and near the edge of keeper. In clamp section, suspension angle had the greatest influence on contact stress, and then the clamp force. The tension force in section played a most important role in these affecting factors. In the exit section of clamp, the biggest impact factor was tension force in this section, then the suspension angle, the third was clamp force. The results provide theoretical basis on reducing corona loss, optimization the clamp. Doubtlessly, the conclusion has important theoretical significance and application value.

  14. Broadband, Polarization-insensitive and Wide-angle Optical Absorber based on Fractal Plasmonics

    CERN Document Server

    Eshaghian, Ali; Chizari, Ata; Mehrany, Khashayar

    2016-01-01

    In this paper, a plasmonic absorber consisting of a metal-dielectric-metal stack with a top layer of Sierpinski nanocarpet is theoretically investigated. Such compact absorber depicts broadband angle-independent behavior over a wide optical wavelength range ($400-700$ nm) and a broad range of angles of light incidence ($0-80^{\\circ}$). Including several feature sizes, such fractal-like structure shows widely strong extinction ($85-99$\\%) response for either transverse electric or magnetic polarization states under normal incidence. Underlying mechanisms of absorbance due to excited surface plasmon modes as well as electric/magnetic dipole resonances are well revealed by investigating electric field, magnetic field and current distributions. The proposed absorber opens a path to realize high-performance ultrathin light trapping devices.

  15. A three-dimensional wide-angle BPM for optical waveguide structures.

    Science.gov (United States)

    Ma, Changbao; Van Keuren, Edward

    2007-01-22

    Algorithms for effective modeling of optical propagation in three- dimensional waveguide structures are critical for the design of photonic devices. We present a three-dimensional (3-D) wide-angle beam propagation method (WA-BPM) using Hoekstra's scheme. A sparse matrix algebraic equation is formed and solved using iterative methods. The applicability, accuracy and effectiveness of our method are demonstrated by applying it to simulations of wide-angle beam propagation, along with a technique for shifting the simulation window to reduce the dimension of the numerical equation and a threshold technique to further ensure its convergence. These techniques can ensure the implementation of iterative methods for waveguide structures by relaxing the convergence problem, which will further enable us to develop higher-order 3-D WA-BPMs based on Padé approximant operators.

  16. Optimizing sensitivity of Unmanned Aerial System optical sensors for low zenith angles and cloudy conditions

    DEFF Research Database (Denmark)

    Wang, Sheng; Dam-Hansen, Carsten; Zarco Tejada, Pablo J.

    Satellite-based imagery in optical domains cannot provide information on the land surface during periods of cloud cover. This issue is especially relevant for high latitudes where overcast days and low solar zenith angles are common. Current remote sensing-based models of evapotranspiration......) with UAV flight campaigns over a willow eddy covariance flux site under different cloudiness levels and solar zenith angles using varying camera settings. Radiance, reflectance, and vegetation indices were validated with ASD measurements and signal to noise metrics and dynamic ranges were assessed. Our....... The multispectral camera (Tetra Mini-MCA6) has 6 channels in the visible and near Infrared. For the laboratory calibration experiment, different camera settings and typical irradiance levels from cloudy to clear sky were designed. The light-source is based on super-continuum generation to produce a continuous solar...

  17. Integrated optical phased array based large angle beam steering system fabricated on silicon-on-insulator

    Science.gov (United States)

    Kwong, David N.; Zhang, Yang; Hosseini, Amir; Chen, Ray T.

    2011-01-01

    In this paper, we present a highly compact silicon nano-membrane based optical phased array fabricated using conventional CMOS processing on silicon-on-insulator that provides for over 10 degrees of beam steering in a silicon slab at λ=1.55μm using transverse-electrical polarized light. A low loss 1-to-12 multi-mode interference (MMI) optical beam splitter with high uniformity is used to provide inputs to the optical phased array. Using an unequally spaced waveguide array permits us to relax the half-wavelength spacing requirement for large angle beam steering, thereby avoiding the optical coupling between adjacent waveguides and reducing the side-lobe-level of the array radiation pattern. S-bend waveguides convert the equally spaced MMI output to the unequally spaced wave guide array, while passively equalizing the phases of each array element to compensate for the MMI output phase profile. Independently controllable thin film metal heaters are used to achieve phase shifting using the strong thermo-optic response of silicon. Heat-insulating air grooves minimize thermal crosstalk, while also achieving and low power consumption.

  18. Relationship Between Peripapillary Atrophy and Optic Disc Parameters in Eyes with Primary Open-Angle Glaucoma

    Directory of Open Access Journals (Sweden)

    Tamer Takmaz

    2011-10-01

    Full Text Available Pur po se: To evaluate the relationship between peripapillary atrophy and optic disc parameters measured by Heidelberg Retina Tomography (HRT and visual field findings in eyes with primary open-angle glaucoma. Methods: Thirty eyes of 30 patients with primary open-angle glaucoma were included in this study. In addition to routine ophthalmic examination, optic disc parameters were evaluated with HRT and visual field was evaluated with Humphrey Visual Field Analyzer. Peripapillary atrophy area was measured by drawing contour of the border of the peripapillary atrophy (Beta zone: chorioretinal atrophy area in which sclera and big choroid blood vessels were seen in HRT. The relationship between this atrophy area and both visual field findings and optic disc parameters was evaluated. Pearson’s correlation coefficient and statistical significance were calculated. Results: The mean age of the patients was 61.4±8.9 years. Measured beta zone area was 0.65±0.40 mm2. Mean deviation measured with Humphrey Visual Field Analyzer was -8.6±8.2 dB and pattern standard deviation was 6.4±4.6. Statistically significant correlation between peripapillary atrophy area and age (PC=0.495, p=0.005, mean deviation (PC=-0.554, p=0.001, cup area (PC=0.382, p=0.037, cup/disc area ratio (PC=0.562, p=0.001, linear cup/disc area ratio (PC=0.422, p=0.020 and mean retinal nerve fiber layer thickness (PC=-0.360, p=0.047 was found. There was not a significant relationship between other optic disc parameters and peripapillary atrophy area (p>0.05. Conclusion: Significant correlation was seen between peripapillary beta zone atrophy area and some important optic disk parameters in primary open-angle glaucoma patients. More meaningful information would have been obtained if sectoral investigation of the optic disc was performed. (Turk J Ophthalmol 2011; 41: 291-4

  19. Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurements

    DEFF Research Database (Denmark)

    Moseev, D.; Meo, Fernando; Korsholm, Søren Bang;

    2012-01-01

    Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements...... require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic...

  20. Phase modulation parallel optical delay detector for microwave angle-of-arrival measurement with accuracy monitored

    CERN Document Server

    Cao, Z; Lu, R; Boom, H P A van den; Tangdiongga, E; Koonen, A M J

    2014-01-01

    A novel phase modulation parallel optical delay detector is proposed for microwave angle-of-arrival (AOA) measurement with accuracy monitored by using only one dual-electrode Mach-Zenhder modulator. A theoretical model is built up to analyze the proposed system including measurement accuracy monitoring. The spatial delay measurement is translated into the phase shift between two replicas of a microwave signal. Thanks to the accuracy monitoring, the phase shifts from 5{\\deg} to 165{\\deg} are measured with less than 3.1{\\deg} measurement error.

  1. Retrieval of vertical profiles of atmospheric refraction angles by inversion of optical dilution measurements

    Directory of Open Access Journals (Sweden)

    D. Fussen

    2015-04-01

    Full Text Available In this paper, we show how the usual change of tangent altitude associated with atmospheric refraction is inseparably connected to a variation of the observed apparent intensity, for extended and pointlike sources. We demonstrate, in the regime of weak refraction angles, that atmospheric optical dilution and image deformation are strictly concomitant. The approach leads to the integration of a simple differential equation related to the observed transmittance in the absence of other absorbing molecules along the optical path. We successfully applied the proposed method to the measurements performed by two past occultation experiments: GOMOS for stellar and ORA for solar occultations. The developed algorithm (named ARID will be applied to the imaging of solar occultations in a forthcoming pico-satellite mission.

  2. Optical phase curves of exoplanets at small and large phase angles

    Science.gov (United States)

    García Muñoz, Antonio

    2016-10-01

    Phase curves and secondary eclipses provide key information on exoplanet atmospheres. Indeed, recent work on close-in giant planets observed by Kepler has shown that it is possible to constrain various reflecting, dynamical and thermal properties of their atmospheres from the analysis of the planets' phase curves. This presentation discusses new diagnostic possibilities for the characterization of exoplanet atmospheres with optical phase curves. These possibilities benefit from the fact that at optical wavelengths the signal from the planet is either partly or mostly determined by scattering of starlight within its atmosphere, which entails that the structure of the planet's phase curve mimics to some extent the optical properties of the atmospheric medium. In particular, we will show how cloud properties such as the particle size or the atmospheric scale height might be constrained through observations at small (i.e. near transit) and large (i.e. near occultation) phase angles. We will emphasize how the interpretation of optical phase curves differs from the interpretation of phase curves obtained at longer wavelengths. The conclusions are relevant to the study of Kepler planets, but also to the investigation of phase curves to be delivered by upcoming space missions such as CHEOPS, JWST, PLATO and TESS.

  3. Optical characterization of liposomes by right angle light scattering and turbidity measurement.

    Science.gov (United States)

    Matsuzaki, K; Murase, O; Sugishita, K; Yoneyama, S; Akada, K; Ueha, M; Nakamura, A; Kobayashi, S

    2000-07-31

    Liposomes have frequently been used as models of biomembranes or vehicles for drug delivery. However, the systematic characterization of lipid vesicles by right angle light scattering and turbidity has not been carried out despite the usefulness of such studies for size estimation. In this study, liposomes of various sizes were prepared by sonication and extrusion. The mean cumulant radii of the vesicles were determined by dynamic light scattering. The lamellarities were estimated based on fluorescence quenching of N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)dipalmitoyl-L-alpha-phosph ati dylethanolamine by sodium dithionite. Right angle light scattering intensity and optical density at 436 nm per unit lipid concentration were measured as a function of vesicle radius. With a vesicle radius < or =100 nm, the optical parameters could be well explained by the Rayleigh-Gans-Debye theory in which the liposomes were modeled as homogeneous spheres with mean refractive indices determined by the volume fractions of lipids in vesicles.

  4. Investigation on the effect of beam divergence angle upon output waveform based on stimulated Brillouin scattering optical limiting

    Institute of Scientific and Technical Information of China (English)

    Hasi Wu-Li-Ji; Lu Huan-Huan; Gong Sheng; Fu Mei-Ling; Lin Zhi-Wei; Lin Dian-Yang; He Wei-Ming

    2009-01-01

    This paper investigates the effect of beam divergence angle on output waveform based on stimulated Brillouin scattering optical limiting. Output waveforms in the case of different pump divergence angles are numerically simulated,and validated in a Nd:YAG seed-injected laser system. The results indicate that a small pump divergence angle can lead to good interaction between pump and Stokes, and a platform can be easily realized in the transmitted waveform.In contrast, a peak followed by the platform appears when the divergence angle becomes large.

  5. Dynamic Imaging of the Eye, Optic Nerve, and Extraocular Muscles With Golden Angle Radial MRI.

    Science.gov (United States)

    Sengupta, Saikat; Smith, David S; Smith, Alex K; Welch, E Brian; Smith, Seth A

    2017-08-01

    The eye and its accessory structures, the optic nerve and the extraocular muscles, form a complex dynamic system. In vivo magnetic resonance imaging (MRI) of this system in motion can have substantial benefits in understanding oculomotor functioning in health and disease, but has been restricted to date to imaging of static gazes only. The purpose of this work was to develop a technique to image the eye and its accessory visual structures in motion. Dynamic imaging of the eye was developed on a 3-Tesla MRI scanner, based on a golden angle radial sequence that allows freely selectable frame-rate and temporal-span image reconstructions from the same acquired data set. Retrospective image reconstructions at a chosen frame rate of 57 ms per image yielded high-quality in vivo movies of various eye motion tasks performed in the scanner. Motion analysis was performed for a left-right version task where motion paths, lengths, and strains/globe angle of the medial and lateral extraocular muscles and the optic nerves were estimated. Offline image reconstructions resulted in dynamic images of bilateral visual structures of healthy adults in only ∼15-s imaging time. Qualitative and quantitative analyses of the motion enabled estimation of trajectories, lengths, and strains on the optic nerves and extraocular muscles at very high frame rates of ∼18 frames/s. This work presents an MRI technique that enables high-frame-rate dynamic imaging of the eyes and orbital structures. The presented sequence has the potential to be used in furthering the understanding of oculomotor mechanics in vivo, both in health and disease.

  6. Effect of incident deposition angle on optical properties and surface roughness of TiO2 thin films

    Science.gov (United States)

    Pan, Yongqiang; Yang, Chen

    2016-10-01

    Optical properties, surface roughness and packing density of TiO2 thin films are studied by obliquely deposited on K9 glass by electron beam evaporation. The surface roughness of TiO2 thin films with different incident deposition angle is compared. The experimental results show that the transmittance increases and transmittance peak shifts to short wavelength with increasing incident deposition angle, the packing density of TiO2 thin films decrease from 0.80 to 0.34 with incident deposition angle increasing from 0° to 75°. The surface roughness of TiO2 thin films increase with increasing incident deposition angle. The surface roughness of TiO2 thin films is slightly bigger than the surface roughness of K9 substrate when the incident deposition angle is 75°. When the incident deposition angle is constant, TiO2 thin films surface roughness decrease with increase of film thickness.

  7. Development of dual-layer GSO depth-of-interaction block detector using angled optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, Satoshi, E-mail: okumura.satoshi@c.mbox.nagoya-u.ac.jp [Nagoya University Graduate School of Medicine (Japan); Yamamoto, Seiichi [Nagoya University Graduate School of Medicine (Japan); Watabe, Hiroshi [Cyclotron and Radioisotope Center (CYRIC), Tohoku University (Japan); Kato, Natsuki; Hamamura, Huka [Nagoya University Graduate School of Medicine (Japan)

    2015-05-01

    A PET system for small animals requires a small detector ring to obtain high-spatial resolution images. However, when we use a relatively large size of photodetector such as a position-sensitive photomultiplier tube (PSPMT), the detector ring is arranged in a hexagonal- or octagonal-shape, and the PET system has large gaps between the block detectors. The large gaps produce image distortion, and the reconstruction algorithm is difficult. To solve these problems, we proposed to arrange two scintillator blocks on one PSPMT using two angled optical fiber-based image guides. We could set two scintillator blocks angled at 22.5° on a PSPMT so that these scintillator blocks are arranged in a nearly circular (hexadecagonal) shape with eight developed block detectors. We used Gd{sub 2}SiO{sub 5} (GSO) scintillators with Ce concentrations of 1.5 mol% (decay time: 39 ns) and 0.4 mol% (decay time: 63 ns). Sizes of these GSO cells were 1.6×2.4×7.0 mm{sup 3} and 1.6×2.4×8.0 mm{sup 3} for 1.5 mol% Ce and 0.4 mol% Ce, respectively. These two types of GSO were arranged in an 11×15 matrix and optically coupled in the depth direction to form a depth-of-interaction (DOI) detector. Two GSO blocks and two optical fiber-based image guides were optically coupled to a 2-in. PSPMT (Hamamatsu Photonics H8500: 8×8 anodes). We measured the performances of the block detector with Cs-137 gamma photons (662-keV). We could resolve almost all pixels clearly in a two-dimensional position histogram. The average peak-to-valley ratios (P/Vs) of the two-dimensional position histogram along profiles were 2.6 and 4.8 in horizontal and vertical directions, respectively. The energy resolution was 28.4% full-width at half-maximum (FWHM). The pulse shape spectra showed good separation with a P/V of 5.2. The developed block detector performed well and shows promise for the development of high-sensitivity and high-spatial resolution PET systems.

  8. Full-angle optical imaging of near-infrared fluorescent probes implanted in small animals

    Institute of Scientific and Technical Information of China (English)

    Gang Hu; Junjie Yao; Jing Bai

    2008-01-01

    To provide a valuable experimental platform for in vivo biomedical research of small animal model with fluorescence mediated approach, we developed a whole-body near-infrared fluorescence molecular imaging system as described in this paper. This system is based on a sensitive CCD camera and has the ability to achieve 360° full-angle source illuminations and projections capture of the targets to obtain the dense sampling by performing rotational scan. The measurement accuracy is validated from cylinder phantom experiments by the comparison between the experimental data and theoretical predictions. Finally, we also present typical in vivo images of fluorescent tube implanted into the mouse body. The results are promising and have proved the system imaging performance for macroscopic optical biomedical research.

  9. Design and characterization of a wearable macrobending fiber optic sensor for human joint angle determination

    Science.gov (United States)

    Silva, Ana S.; Catarino, André; Correia, Miguel V.; Frazão, Orlando

    2013-12-01

    The work presented here describes the development and characterization of intensity fiber optic sensor integrated in a specifically designed piece of garment to measure elbow flexion. The sensing head is based on macrobending incorporated in the garment, and the increase of curvature number was studied in order to investigate which scheme provided a good result in terms of sensitivity and repeatability. Results showed the configuration that assured a higher sensitivity (0.644 dBm/deg) and better repeatability was the one with four loops. Ultimately, this sensor can be used for rehabilitation purposes to monitor human joint angles, namely, elbow flexion on stroke survivors while performing the reach functional task, which is the most common upper-limb human gesture.

  10. Identification of iridocorneal angle structures assessed by Fourier domain optical coherence tomography.

    Science.gov (United States)

    Fernández-Vigo, J I; Fernández-Vigo, C; Martínez de la Casa, J M; Sáenz-Francés, F; Santos-Bueso, E; García Feijóo, J; Fernández-Vigo, J A

    2016-02-01

    To study the structures of the iridocorneal angle using anterior segment optical coherence tomography (OCT) defining their tomographic characteristics and quantifying their identification frequency. A cross-sectional study was performed on 267 right eyes of 267 consecutive healthy patients. Fourier domain OCT RTVue (Optovue Inc, CA, EE. UU.) was used to examine the iridocorneal angle in the nasal and temporal sectors. The structures evaluated were: Sclerocorneal limbus, sclerocorneal transition, Schwalbe's line, trabecular meshwork, Schlemm's canal, scleral spur, and angular recess. Within and between agreements to identify structures were calculated using Cohen's kappa coefficient. The mean age was 41.3 ± 14.3 years (range 20-80), with 57% being women. The sclerocorneal limbus, sclerocorneal transition, and Schwalbe's line were identified by 98.7, 97 and 93.4% of the images, respectively, with the trabecular meshwork and Schlemm's canal being identified in 91% of cases. The scleral spur could be identified in 85.4%, and the angular recess in 74.5%. There was no difference in the identification between the temporal and nasal sectors. Within and between agreement was k=0.92 and k=0.88, respectively, in the identification of the structures of the total images studied. Fourier domain OCT is a reliable technique for the identification of the structures of the iridocorneal angle, among which can be highlighted are, the trabecular meshwork, Schlemm's canal, scleral spur, and Schwalbe's line. Copyright © 2015 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  11. Scattering angle resolved optical coherence tomography for in vivo murine retinal imaging

    Science.gov (United States)

    Gardner, Michael R.; Katta, Nitesh; McElroy, Austin; Baruah, Vikram; Rylander, H. G.; Milner, Thomas E.

    2017-02-01

    Optical coherence tomography (OCT) retinal imaging contributes to understanding central nervous system (CNS) diseases because the eye is an anatomical "window to the brain" with direct optical access to nonmylenated retinal ganglion cells. However, many CNS diseases are associated with neuronal changes beyond the resolution of standard OCT retinal imaging systems. Though studies have shown the utility of scattering angle resolved (SAR) OCT for particle sizing and detecting disease states ex vivo, a compact SAR-OCT system for in vivo rodent retinal imaging has not previously been reported. We report a fiber-based SAR-OCT system (swept source at 1310 nm +/- 65 nm, 100 kHz scan rate) for mouse retinal imaging with a partial glass window (center aperture) for angular discrimination of backscattered light. This design incorporates a dual-axis MEMS mirror conjugate to the ocular pupil plane and a high collection efficiency objective. A muring retina is imaged during euthanasia, and the proposed SAR-index is examined versus time. Results show a positive correlation between the SAR-index and the sub-cellular hypoxic response of neurons to isoflurane overdose during euthanasia. The proposed SAR-OCT design and image process technique offer a contrast mechanism able to detect sub-resolution neuronal changes for murine retinal imaging.

  12. Simultaneous optical losses and current measurements in photovoltaic devices at variable angle of the incident light

    Energy Technology Data Exchange (ETDEWEB)

    Maddalena, P.; Tortora, P. [Universita di Napoli ' Frederico II' , Napoli (Italy). INFM, Dipartimento di Scienze Fisiche; Parretta, A. [Centro Ricerche ENEA, Portici (Italy); Altermatt, P.; Zhao, J. [University of New South Wales, Sydney (Australia). Photovoltaic Special Research Centre

    2003-02-01

    In this work, the apparatus and the method for a simultaneous measurement of the optical losses and short-circuit current in a solar cell, at variable incidence angle of the light, is presented. The method has been applied to an n{sup +}/p c-Si cell with a polished surface. The investigation has been performed over an angular range from 8{sup o} to 80{sup o}, using a linearly polarized laser beam, either normally or parallelly polarized with respect to the incidence plane. The experimental curves of reflectance seem to be in a good agreement with the theoretical ones derived from the Fresnel equations. Since the measurements are performed inside an integrating sphere, a procedure has been developed to derive, from the total current I{sup tot}, the calculated direct one, I{sub dirCal} excluding contributions from the incoming light back-diffused to the cell under investigation; the results are compared with real direct-current measurement. Since with the proposed method both reflectance and current are measured for the same surface region and under identical illumination conditions, the results have been combined to get the internal spectral response of the n{sup +}/p c-Si polished surface solar cell. (author)

  13. Orbit Determination with Angle-only Data from the First Korean Optical Satellite Tracking System, OWL-Net

    Science.gov (United States)

    Choi, J.; Jo, J.

    2016-09-01

    The optical satellite tracking data obtained by the first Korean optical satellite tracking system, Optical Wide-field patrol - Network (OWL-Net), had been examined for precision orbit determination. During the test observation at Israel site, we have successfully observed a satellite with Laser Retro Reflector (LRR) to calibrate the angle-only metric data. The OWL observation system is using a chopper equipment to get dense observation data in one-shot over 100 points for the low Earth orbit objects. After several corrections, orbit determination process was done with validated metric data. The TLE with the same epoch of the end of the first arc was used for the initial orbital parameter. Orbit Determination Tool Kit (ODTK) was used for an analysis of a performance of orbit estimation using the angle-only measurements. We have been developing batch style orbit estimator.

  14. Modification of the morphology and optical properties of SnS films using glancing angle deposition technique

    Science.gov (United States)

    Sazideh, M. R.; Dizaji, H. Rezagholipour; Ehsani, M. H.; Moghadam, R. Zarei

    2017-05-01

    Tin sulfide (SnS) films were prepared by thermal evaporation method using Glancing Angle Deposition (GLAD) technique at zero and different oblique incident flux angles (α = 45°, 55°, 65°, 75° and 85°). The physical properties of prepared films were systematically investigated. The X-ray diffraction analysis indicated that the film deposited at α = 0° formed as single phase with an orthorhombic structure. However, the layers became amorphous at α = 45°, 55°, 65°, 75° and 85°. Beside the appearance of amorphous feature in the film prepared at α higher than zero, Sn2S3 phase was also observed. The top and cross-sectional field emission scanning electron microscope (FESEM) images of the samples showed noticeable changes in the structure and morphology of individual nano-plates as a function of incident angle. The band gap and refractive index values of the films were calculated by optical transmission measurements. The optical band-gap values were observed to increase with increasing the incident flux angle. This can be due to presence of Sn2S3 phase observed in the samples produced at α values other than zero. The effective refractive index and porosity exhibit an opposite evolution as the incident angle α rises. At α = 85° the layers show a considerable change in effective refractive index (Δn = 1.7) at near-IR spectral range.

  15. Cell-Detection Technique for Automated Patch Clamping

    Science.gov (United States)

    McDowell, Mark; Gray, Elizabeth

    2008-01-01

    A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image

  16. Structural, Morphological and Optical Properties of Sn3Sb2S6 Thin Films Synthesized by Oblique Angle Deposition

    Science.gov (United States)

    Larbi, A.; Chaffar Akkari, F.; Dahman, H.; Demaille, D.; Gallas, B.; Kanzari, M.

    2016-10-01

    The oblique angle deposition technique has attracted a lot attention in many different applications due to its unique advantage of programmable nanocolumns. In this work we use this technique to investigate the physical properties of obliquely thermal evaporated Sn3Sb2S6 thin films deposited onto unheated glass and silicon substrates, inclined from the flux vapor source at the deposition angles 0°, 40°, 60°, 75° and 85°. X-ray diffraction (XRD) and UV-Visible and near infrared (UV-Vis-IFR) analysis were used respectively to characterize the structural and optical properties of the layers. The influence of flux angle on the surface morphology and the microstructure was investigated by using scanning electron microscopy. The optical constants were obtained from analysis of the experimental recorded transmission and reflectance spectral data over the wavelength range 300 nm to 1800 nm. The band gaps of the synthesized thin films were found to be direct allowed transitions and increased from 1.44 eV to 1.66 eV with increasing γ from 0° to 85°, respectively. The absorption coefficients of the films are in the range of 105 cm-1 to 106 cm-1. The refractive indexes were evaluated in the transparent region in terms of the envelope method suggested by the Swanepoel model. It has been found that the refractive index decreases from 2.66 to 2.06 with increasing deposition angle from 0° to 85°, respectively. The relationship between the flux incident angles γ and the column angle β was also explored. The oblique angle deposition films showed an inclined columnar structure, with columns tilting in the direction of the incident flux. The effective packing densities of the synthesized Sn3Sb2S6 thin films were calculated using Bruggeman effective medium approximation.

  17. Trabecular-Iris Circumference Volume in Open Angle Eyes Using Swept-Source Fourier Domain Anterior Segment Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Mohammed Rigi

    2014-01-01

    Full Text Available Purpose. To introduce a new anterior segment optical coherence tomography parameter, trabecular-iris circumference volume (TICV, which measures the integrated volume of the peripheral angle, and establish a reference range in normal, open angle eyes. Methods. One eye of each participant with open angles and a normal anterior segment was imaged using 3D mode by the CASIA SS-1000 (Tomey, Nagoya, Japan. Trabecular-iris space area (TISA and TICV at 500 and 750 µm were calculated. Analysis of covariance was performed to examine the effect of age and its interaction with spherical equivalent. Results. The study included 100 participants with a mean age of 50 (±15 years (range 20–79. TICV showed a normal distribution with a mean (±SD value of 4.75 µL (±2.30 for TICV500 and a mean (±SD value of 8.90 µL (±3.88 for TICV750. Overall, TICV showed an age-related reduction (P=0.035. In addition, angle volume increased with increased myopia for all age groups, except for those older than 65 years. Conclusions. This study introduces a new parameter to measure peripheral angle volume, TICV, with age-adjusted normal ranges for open angle eyes. Further investigation is warranted to determine the clinical utility of this new parameter.

  18. Development of a score and probability estimate for detecting angle closure based on anterior segment optical coherence tomography.

    Science.gov (United States)

    Nongpiur, Monisha E; Haaland, Benjamin A; Perera, Shamira A; Friedman, David S; He, Mingguang; Sakata, Lisandro M; Baskaran, Mani; Aung, Tin

    2014-01-01

    To develop a score along with an estimated probability of disease for detecting angle closure based on anterior segment optical coherence tomography (AS OCT) imaging. Cross-sectional study. A total of 2047 subjects 50 years of age and older were recruited from a community polyclinic in Singapore. All subjects underwent standardized ocular examination including gonioscopy and imaging by AS OCT (Carl Zeiss Meditec). Customized software (Zhongshan Angle Assessment Program) was used to measure AS OCT parameters. Complete data were available for 1368 subjects. Data from the right eyes were used for analysis. A stepwise logistic regression model with Akaike information criterion was used to generate a score that then was converted to an estimated probability of the presence of gonioscopic angle closure, defined as the inability to visualize the posterior trabecular meshwork for at least 180 degrees on nonindentation gonioscopy. Of the 1368 subjects, 295 (21.6%) had gonioscopic angle closure. The angle closure score was calculated from the shifted linear combination of the AS OCT parameters. The score can be converted to an estimated probability of having angle closure using the relationship: estimated probability = e(score)/(1 + e(score)), where e is the natural exponential. The score performed well in a second independent sample of 178 angle-closure subjects and 301 normal controls, with an area under the receiver operating characteristic curve of 0.94. A score derived from a single AS OCT image, coupled with an estimated probability, provides an objective platform for detection of angle closure. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Review of small-angle coronagraphic techniques in the wake of ground-based second-generation adaptive optics systems

    CERN Document Server

    Mawet, Dimitri; Lawson, Peter; Mugnier, Laurent; Traub, Wesley; Boccaletti, Anthony; Trauger, John; Gladysz, Szymon; Serabyn, Eugene; Milli, Julien; Belikov, Ruslan; Kasper, Markus; Baudoz, Pierre; Macintosh, Bruce; Marois, Christian; Oppenheimer, Ben; Barrett, Harrisson; Beuzit, Jean-Luc; Devaney, Nicolas; Girard, Julien; Guyon, Olivier; Krist, John; Mennesson, Bertrand; Mouillet, David; Murakami, Naoshi; Poyneer, Lisa; Savransky, Dmitri; ́erinaud, Christophe V; Wallace, James K

    2012-01-01

    Small-angle coronagraphy is technically and scientifically appealing because it enables the use of smaller telescopes, allows covering wider wavelength ranges, and potentially increases the yield and completeness of circumstellar environment - exoplanets and disks - detection and characterization campaigns. However, opening up this new parameter space is challenging. Here we will review the four posts of high contrast imaging and their intricate interactions at very small angles (within the first 4 resolution elements from the star). The four posts are: choice of coronagraph, optimized wavefront control, observing strategy, and post-processing methods. After detailing each of the four foundations, we will present the lessons learned from the 10+ years of operations of zeroth and first-generation adaptive optics systems. We will then tentatively show how informative the current integration of second-generation adaptive optics system is, and which lessons can already be drawn from this fresh experience. Then, w...

  20. Management of umbilical cord clamping.

    Science.gov (United States)

    Webbon, Lucy

    2013-02-01

    The Royal College of Midwives (RCM) has updated its third stage of labour guidelines (RCM 2012) to be clearly supportive of a delay in umbilical cord clamping, although specific guidance on timing is yet to be announced. It is therefore imperative that both midwives and student midwives understand and are able to integrate delaying into their practice, as well as communicating to women the benefits; only in this way can we give women fully informed choices on this aspect of care. The main benefit of delayed cord clamping is the protection it can provide in reducing childhood anaemia, which is a major issue, especially in poorer countries. A review of the evidence found no risks linked to delayed clamping, and no evidence that it cannot be used in combination with the administration of uterotonic drugs. Delayed cord clamping can be especially beneficial for pre term and compromised babies.

  1. The impact of the detection angle on the quantitative measurement of hemoglobin oxygen saturation in optical-resolution photoacoustic microscopy

    Science.gov (United States)

    Wu, Ning; Li, Changhui

    2016-10-01

    Optical-resolution photoacoustic microscopy (OR-PAM) plays an important role in the quantitative measurement of hemoglobin oxygen saturation (SO2) at a single vessel level. In this study, we reported that the relative angle between light illumination and ultrasonic detection could have a significant impact on the SO2 measurement. Both simulation and phantom studies were provided, and this result will help the system design and result interpretation of the functional OR-PAM.

  2. Structure and optical properties of ZnS thin films grown by glancing angle deposition

    Science.gov (United States)

    Wang, Sumei; Fu, Xiaoyong; Xia, Guodong; Wang, Jianguo; Shao, Jianda; Fan, Zhengxiu

    2006-10-01

    The glancing angle deposition (GLAD) technique was used to deposit ZnS films by electron beam evaporation method. The cross sectional scanning electron microscopy (SEM) image illustrated a highly orientated microstructure composed of slanted column. The atomic force microscopy (AFM) analysis indicated that incident flux angle had significant effects on the nodule size and surface roughness. Under identical nominal thickness, the actual thickness of the GLAD films is related to the incident flux angle. The refractive index and in-plane birefringence of the GLAD ZnS films were discussed, and the maximum birefringence Δ n = 0.036 was obtained at incident flux angle of α = 80°. Therefore, the glancing angle deposition technique is a promising way to create a columnar structure with enhanced birefringent property.

  3. Crank angle resolved flow field characterization of a heavy-duty one-cylinder optical engine

    Energy Technology Data Exchange (ETDEWEB)

    Van der Meyden, T.J.

    2009-03-15

    Soot and nitric oxide (NOx) production are the main negative aspects of Diesel combustion. This is why new combustion strategies are being investigated, such as Premixed Charge Compression Ignition (PCCI). PCCI is one of the most promising combustion strategies for internal combustion engines in the future, since PCCI combustion is able to realize very low soot and nitric oxide emissions. PCCI combines the efficiency of a diesel and the low particulate emission of an Otto engine. To achieve PCCI combustion with limited heat release rates, the influence of charge stratification on combustion should be investigated. In this work, the first steps to achieve that goal are made. The first step is to determine in-cylinder velocities by measuring flow fields using Particle Image Velocimetry (PIV). The test setup consists of a one-cylinder optically accessible heavy duty engine driven by an electrical motor. The upper part of the liner and piston bottom are both made of sapphire. For PIV measurements a 10 Hz Nd:YAG Continuum Surelite laser is used with pulse energies of 140 mJ. The used camera is a Kodak Megaplus ES 1.0 CCD with 1008 x 1018 pixels. The seeding particles are produced from silicon oil using Laskin nozzles and have a diameter of about 0.7 im. Pre- and post- processing and the evaluation of the recorded PIV images is done using the commercially available software program PIVview (Pivtec). The velocity analysis is done using the commercial software program Tecplot. More knowledge is gathered on the in-cylinder velocities, aimed at a future detailed study on the effect of charge stratification in PCCI combustion. Ensemble averaged velocities, vorticities and strain rates, turbulence intensities and turbulent kinetic energies as a function of the crank angle, engine speed, measurement height and compression ratio have been investigated. Velocity and turbulence appear to be proportional to the engine speed. The position of the ensemble averaged swirl center as a

  4. Optical properties of Cd1-xZnxTe films in a device structure using variable angle spectroscopic ellipsometry

    Science.gov (United States)

    Paulson, P. D.; McCandless, B. E.; Birkmire, R. W.

    2004-03-01

    The optical properties of polycrystalline Cd1-xZnxTe alloy thin films in device structures are reported for energy from 0.8 to 4.6 eV. Cd1-xZnxTe alloy thin films with x from 0 to 1 were deposited on glass/indium-tin-oxide (ITO)/CdS substrates by coevaporation from CdTe and ZnTe sources and were characterized by variable angle spectroscopic ellipsometry, energy dispersive x-ray spectroscopy, and x-ray diffractometry. The Cd1-xZnxTe films are single phase with a zincblende crystal structure over the entire alloy range. The Cd1-xZnxTe optical constants were determined using a multilayer optical model incorporating the optical constants of glass, ITO and CdS, determined independently from glass, glass/ITO, and glass/ITO/CdS specimens. The optical constants of the Cd1-xZnxTe thin films are comparable to literature values reported for single crystals, indicating that the polycrystalline nature of the films does not measurably alter the optical constants. A semiconductor alloy model for determining the composition of CdxZn1-xTe alloy films is developed using the optical data obtained from the analysis. This alloy model can be used to evaluate compositional grading and the effects of Cd1-xZnxTe film processing.

  5. Feasibility study on fiber-optic goniometer for measuring knee joint angle

    Science.gov (United States)

    Kim, Seon Geun; Jang, Kyoung Won; Yoo, Wook Jae; Shin, Sang Hun; Cho, Seunghyun; Lee, Bongsoo

    2014-09-01

    In this study, we fabricated a fiber-optic goniometer using a plastic optical fiber, a light-emitting diode, and a photodiode. The cladding of the plastic optical fiber was removed at 0.5-3mm intervals regularly to increase the bending loss of the plastic optical fiber. Also, the output voltages of the photodiode based on light intensity that measured using the fiber-optic goniometer were measured light intensities using the fiber-optic goniometer were measured to evaluate the linearity of the fiber-optic goniometer. Finally, we measured the responses of the fiber-optic goniometer for gait speeds of 3, 5, and 10 km/h using a data acquisition board and a LabVIEW program.

  6. Phase-resolved detection of the spin Hall angle by optical ferromagnetic resonance in perpendicularly magnetized thin films

    Science.gov (United States)

    Capua, Amir; Wang, Tianyu; Yang, See-Hun; Rettner, Charles; Phung, Timothy; Parkin, Stuart S. P.

    2017-02-01

    The conversion of charge current to spin current by the spin Hall effect is of considerable current interest from both fundamental and technological perspectives. Measurement of the spin Hall angle, especially for atomically thin systems with large magnetic anisotropies, is not straightforward. Here we demonstrate a hybrid phase-resolved optical-electrical ferromagnetic resonance method that we show can robustly determine the spin Hall angle in heavy-metal/ferromagnet bilayer systems with large perpendicular magnetic anisotropy. We present an analytical model of the ferromagnetic resonance spectrum in the presence of the spin Hall effect, in which the spin Hall angle can be directly determined from the changes in the amplitude response as a function of the spin current that is generated from a dc charge current passing through the heavy-metal layer. Increased sensitivity to the spin current is achieved by operation under conditions for which the magnetic potential is shallowest at the "Smit point." Study of the phase response reveals that the spin Hall angle can be reliably extracted from a simplified measurement that does not require scanning over time or magnetic field but rather only on the dc current. The method is applied to the Pt-Co/Ni/Co system whose spin Hall angle was to date characterized only indirectly and that is especially relevant for spin-orbit torque devices.

  7. Numerical simulation of the optical characteristics of autostereoscopic displays that have an aspherical lens array with a slanted angle.

    Science.gov (United States)

    Jung, Sung-Min; Kang, In-Byeong

    2014-02-10

    We developed a 3D simulation model describing the optical phenomena on a slanted lenticular surface with aspherical lenses for autostereoscopic displays and analyzed the optical behavior of the multiview autostereoscopic display under actual design conditions by using a 3D simulation model. Optical characteristics, such as 3D crosstalk and 3D luminance differences, are obtained from the simulation of the light distribution for the multiview autostereoscopic displays with slated angles of 0.0°, 9.46°, 12.59°, and 14.04°. By investigating the effect of the conic constant of an aspherical lens surface on the 3D crosstalk and the 3D luminance differences for given several design conditions, we find the optimal values of the conic constant for slanted angles of 0.0° and 9.46° in order to minimize the 3D crosstalk and the 3D luminance difference. From these results, we think that our simulation model is very useful for designing the lens array to optimize the optical characteristics of autostereoscopic displays.

  8. Energy-dispersive small-angle X-ray scattering with cone collimation using X-ray capillary optics

    Science.gov (United States)

    Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi

    2016-09-01

    Energy-dispersive small-angle X-ray scattering (ED-SAXS) with an innovative design of cone collimation based on an ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL) had been explored. Using this new cone collimation system, scattering angle 2θ has a theoretical minimum angle related to the mean half-opening angle of the hollow cone beam of 1.42 mrad, and with the usable X-ray energy ranging from 4 to 30 keV, the resulting observable scattering vector q is down to a minimum value of about 0.003 Å-1 (or a Bragg spacing of about 2100 Å). However, the absorption of lower energies by X-ray capillary optics, sample transmission, and detector response function limits the application range to lower energy. Cone collimation ED-SAXS experiments carried out on pure water, Lupolen, and in situ temperature-dependent measurement of diacetylenic acid/melamine micelle solid were presented at three different scattering angles 2θ of 0.18°, 0.70° and 1.18° to illustrate the new opportunities offered by this technique as well as its limitations. Also, a comparison has been made by replacing the PPXRL with a pinhole, and the result shows that cone collimation ED-SAXS based on ESBC with PPXRL was helpful in improving the signal-to-noise ratio (i.e., reducing the parasitic background scattering) than ESBC with a pinhole. The cone collimation instrument based on X-ray capillary optics could be considered as a promising tool to perform SAXS experiments, especially cone collimation ED-SAXS has potential application for the in situ temperature-dependent studying on the kinetics of phase transitions.

  9. Retrieval of Aerosol Optical Depth Using the Empirical Orthogonal Functions (EOFs Based on PARASOL Multi-Angle Intensity Data

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2017-06-01

    Full Text Available Aerosol optical depth (AOD is a widely used aerosol optical parameter in atmospheric physics. To obtain this parameter precisely, many institutions plan to launch satellites with multi-angle measurement sensors, but one important step in aerosol retrieval, the estimation of surface reflectance, is still a pressing issue. This paper presents an AOD retrieval method based on the multi-angle intensity data from the Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL platform using empirical orthogonal functions (EOFs, which can be universally applied to multi-angle observations. The function of EOFs in this study is to estimate surface intensity contributions, associated with aerosol lookup tables (LUTs, so that the retrieval of AOD can be implemented. A comparison of the retrieved AODs for the Beijing, Xianghe, Taihu, and Hongkong_PolyU sites with those from the Aerosol Robotic Network (AERONET ground-based observations produced high correlation coefficients (r of 0.892, 0.915, 0.831, and 0.897, respectively, while the corresponding root mean square errors (RMSEs are 0.095, 0.093, 0.099, and 0.076, respectively.

  10. Comparison of Scheimpflug imaging and spectral domain anterior segment optical coherence tomography for detection of narrow anterior chamber angles.

    Science.gov (United States)

    Grewal, D S; Brar, G S; Jain, R; Grewal, S P S

    2011-05-01

    To compare the performance of anterior chamber volume (ACV) and anterior chamber depth (ACD) obtained using Scheimpflug imaging with angle opening distance (AOD500) and trabecular-iris space area (TISA500) obtained using spectral domain anterior segment optical coherence tomography (SD-ASOCT) in detecting narrow angles classified using gonioscopy. In this prospective, cross-sectional observational study, 265 eyes of 265 consecutive patients underwent sequential Scheimpflug imaging, SD-ASOCT imaging, and gonioscopy. Correlations between gonioscopy grading, ACV, ACD, AOD500, and TISA500 were evaluated. Area under receiver operating characteristic curve (AUC), sensitivity, specificity, and likelihood ratios (LRs) were calculated to assess the performance of ACV, ACD, AOD500, and TISA500 in detecting narrow angles (defined as Shaffer grade ≤1 in all quadrants). SD-ASOCT images were obtained at the nasal and temporal quadrants only. Twenty-eight eyes (10.6%) were classified as narrow angles on gonioscopy. ACV correlated with gonioscopy grading (PACV correlated with TISA500 for nasal (r=0.135, P=0.029) and temporal (P=0.160, P=0.009) quadrants and also with AOD500 for nasal (r=0.498, PACV (AUC=0.935; 95% confidence interval (CI) =0.898-0.961) performed similar to ACD (AUC=0.88, P=0.06) and significantly better than AOD500 nasal (AUC=0.761, P=0.001), AOD500 temporal (AUC=0.808, PACV had 90% sensitivity and 88% specificity for detecting narrow angles. Positive and negative LRs for ACV were 8.63 (95% CI=7.4-10.0) and 0.11 (95% CI=0.03-0.4), respectively. ACV measurements using Scheimpflug imaging outperformed AOD500 and TISA500 using SD-ASOCT for detecting narrow angles.

  11. Robotic Partial Nephrectomy Using Robotic Bulldog Clamps

    OpenAIRE

    2011-01-01

    Background and Objectives: The need for a skilled assistant to perform hilar clamping during robotic partial nephrectomy is a potential limitation of the technique. We describe our experience using robotic bulldog clamps applied by the console surgeon for hilar clamping. Methods: A total of 60 consecutive patients underwent robotic partial nephrectomy, 30 using laparoscopic bulldog clamps applied by the assistant and 30 using robotic bulldog clamps applied with the robotic Prograsp instrument...

  12. Glancing angle deposition of SiO{sub 2} thin film microstructures: Investigations of optical and morphological properties

    Energy Technology Data Exchange (ETDEWEB)

    Tokas, R. B., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Jena, S., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Sarkar, P., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Thakur, S., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com; Sahoo, N. K., E-mail: tokasstar@gmail.com, E-mail: tokasstar@gmail.com [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

    2014-04-24

    In present work, the optical and the morphological properties of micro-structured SiO{sub 2} thin films fabricated by using glancing angle deposition (GLAD) technique has been carried out. The results are compared with the normally deposited SiO{sub 2} films for the gained advantages. The influence of the glancing angle on the refractive index of porous SiO{sub 2} film was investigated by the spectral transmission measurement in 400–950 nm wavelength regimes. The refractive index has been found to be 1.14@532 nm for the porous SiO{sub 2} film deposited at a glancing angle of 85°. The density and surface qualities of these samples were primarily investigated by using grazing angle X-ray reflectivity (GIXR) and atomic force microscope (AFM) measurements. Results indicate a substantial decrease in film density and refractive index and increase in surface roughness and grain size for GLAD SiO{sub 2} compared to normally deposited SiO{sub 2} films.

  13. Large deflection angle, high-power adaptive fiber optics collimator with preserved near-diffraction-limited beam quality.

    Science.gov (United States)

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

    2016-05-15

    We report on the development of a monolithic adaptive fiber optics collimator, with a large deflection angle and preserved near-diffraction-limited beam quality, that has been tested at a maximal output power at the 300 W level. Additionally, a new measurement method of beam quality (M2 factor) is developed. Experimental results show that the deflection angle of the collimated beam is in the range of 0-0.27 mrad in the X direction and 0-0.19 mrad in the Y direction. The effective working frequency of the device is about 710 Hz. By employing the new measurement method of the M2 factor, we calculate that the beam quality is Mx2=1.35 and My2=1.24, which is in agreement with the result from the beam propagation analyzer and is preserved well with the increasing output power.

  14. ITER-like wide-angle infrared thermography and visible observation diagnostic using reflective optics

    NARCIS (Netherlands)

    Gauthier, E.; Roche, H.; Thomas, E.; Droineau, S.; Bertrand, B.; Migozzi, J.B.; Vliegenthart, W.A.; Dague, L.; Andrew, P.; Tiscornia, T.; Sands, D.

    2007-01-01

    Control of the plasma-wall interaction during transient events will be a critical issue in ITER. A new ITER-like wide-angle infrared and visible diagnostic, allowing to observe plasma wall interaction in the main chamber, has been installed on JET. The design and the manufacture of the diagnostic

  15. ITER-like wide-angle infrared thermography and visible observation diagnostic using reflective optics

    NARCIS (Netherlands)

    Gauthier, E.; Roche, H.; Thomas, E.; Droineau, S.; Bertrand, B.; Migozzi, J.B.; Vliegenthart, W.A.; Dague, L.; Andrew, P.; Tiscornia, T.; Sands, D.

    2007-01-01

    Control of the plasma-wall interaction during transient events will be a critical issue in ITER. A new ITER-like wide-angle infrared and visible diagnostic, allowing to observe plasma wall interaction in the main chamber, has been installed on JET. The design and the manufacture of the diagnostic an

  16. Evidence for Three-Dimensional Radiative Effects in MODIS Cloud Optical Depths Retrieved at Back Scattering View Angles

    Science.gov (United States)

    Varnai, Tamas; Marshak, Alexander

    2003-01-01

    This study addresses the question whether 1D radiative transfer theory describes well the angular distribution of shortwave cloud reflection. The statistical analysis of a large set of MODIS observations indicates that in oblique backward scattering directions, cloud reflection is stronger than 1D theory would predict. After considering a variety of possible causes, the paper concludes that the most likely reason for the increase lies in 3D radiative interactions. The results' main implication is that cloud optical depths retrieved at back scattering view angles larger than about 50 degrees tend to be overestimated and should be used only with great caution.

  17. Optical sectioning using a fiber probe with an angled illumination-collection geometry: evaluation in engineered tissue phantoms

    Science.gov (United States)

    Nieman, Linda; Myakov, Alexey; Aaron, Jesse; Sokolov, Konstantin

    2004-02-01

    We present a fiber optic probe that combines polarized illumination and detection with an angled distal probe geometry to detect the size-dependent scattering at a specific depth within epithelium. Analysis of the scattering signal by use of Mie theory allows the extraction of scatterer size and size distribution-key parameters for precancer detection. The probe was evaluated in two tissue phantoms: polystyrene beads atop collagen gel and multiple layers of cancer cells atop collagen. We also present in vivo measurements in the oral cavity of normal volunteers. The sizes of scatterers extracted from the scattering spectra corresponded to independently measured values.

  18. Clamp wins pipe repair prize

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-04-01

    This paper describes the permanent pipeline repair system, developed by Tekmar, which is powered by seawater hydraulics and is easily installed and tested by any workclass remotely operated vehicle (rov). Details are given of the two main components of the system, namely, the diverless high pressure split repair clamp and the rov-operated tool to install it.

  19. Automated planar patch-clamp.

    Science.gov (United States)

    Milligan, Carol J; Möller, Clemens

    2013-01-01

    Ion channels are integral membrane proteins that regulate the flow of ions across the plasma membrane and the membranes of intracellular organelles of both excitable and non-excitable cells. Ion channels are vital to a wide variety of biological processes and are prominent components of the nervous system and cardiovascular system, as well as controlling many metabolic functions. Furthermore, ion channels are known to be involved in many disease states and as such have become popular therapeutic targets. For many years now manual patch-clamping has been regarded as one of the best approaches for assaying ion channel function, through direct measurement of ion flow across these membrane proteins. Over the last decade there have been many remarkable breakthroughs in the development of technologies enabling the study of ion channels. One of these breakthroughs is the development of automated planar patch-clamp technology. Automated platforms have demonstrated the ability to generate high-quality data with high throughput capabilities, at great efficiency and reliability. Additional features such as simultaneous intracellular and extracellular perfusion of the cell membrane, current clamp operation, fast compound application, an increasing rate of parallelization, and more recently temperature control have been introduced. Furthermore, in addition to the well-established studies of over-expressed ion channel proteins in cell lines, new generations of planar patch-clamp systems have enabled successful studies of native and primary mammalian cells. This technology is becoming increasingly popular and extensively used both within areas of drug discovery as well as academic research. Many platforms have been developed including NPC-16 Patchliner(®) and SyncroPatch(®) 96 (Nanion Technologies GmbH, Munich), CytoPatch™ (Cytocentrics AG, Rostock), PatchXpress(®) 7000A, IonWorks(®) Quattro and IonWorks Barracuda™, (Molecular Devices, LLC); Dynaflow(®) HT (Cellectricon

  20. Optical characterization of bubbly flows with a near-critical-angle scattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Onofri, Fabrice R.A.; Krzysiek, Mariusz [IUSTI, UMR, CNRS, University of Provence, Polytech' DME, Technopole Chateau-Gombert, Marseille (France); Mroczka, Janusz [CEPM, Technical University of Wroclaw, Wroclaw (Poland); Ren, Kuan-Fang [CORIA, UMR, CNRS, University of Rouen, Saint-Etienne-du-Rouvray (France); Radev, Stefan [IMECH, Bulgarian Academy of Sciences, Sofia (Bulgaria); Bonnet, Jean-Philippe [M2P2, UMR, CNRS, University Paul Cezanne, Aix-en-Provence (France)

    2009-10-15

    The newly developed critical angle refractometry and sizing technique (CARS) allows simultaneous and instantaneous characterization of the local size distribution and the relative refractive index (i.e. composition) of a cloud of bubbles. The paper presents the recent improvement of this technique by comparison of different light scattering models and inversion procedures. Experimental results carried in various air/water and air/water-ethanol bubbly flows clearly demonstrate the efficiency and the potential of this technique. (orig.)

  1. Optic probe for multiple angle image capture and optional stereo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Malone, Robert M.; Kaufman, Morris I.

    2016-11-29

    A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

  2. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics.

    NARCIS (Netherlands)

    Springelkamp, H. (Henriët); Iglesias, A.I. (Adriana); Mishra, A. (Aniket); Höhn, R. (René); Wojciechowski, R. (Robert); Khawaja, A.P. (Anthony); Nag, A. (Abhishek); Wang, Y.X. (Ya Xing); Wang, J.J. (Jie Jin); Cuellar-Partida, G. (Gabriel); Gibson, J. (Jane); Cooke Bailey, J.N. (Jessica); Vithana, E.N. (Eranga); Gharahkhani, P. (Puya); Boutin, T. (Thibaud); Ramdas, W.D. (Wishal); Zeller, T. (Tanja); Luben, R.N. (Robert); Yonova-Doing, E. (Ekaterina); Viswanathan, A.C. (Ananth); Yazar, S. (Seyhan); Cree, A.J. (Angela); Haines, J.L. (Jonathan); Koh, J.Y. (Jia Yu); Souzeau, E. (Emmanuelle); Wilson, J.F. (James); Amin, N. (Najaf); Müller, C. (Christian); Venturini, C. (Cristina); Kearns, L.S. (Lisa); Hee Kang, J. (Jae); Consortium, N. (Neighborhood); Tham, Y.C. (Yih Chung); Zhou, T. (Tiger); van Leeuwen, E.M. (Elisabeth); Nickels, S. (Stefan); Sanfilippo, P. (Paul); Liao, J. (Jiemin); Linde, H.V. (Herma van der); Zhao, W. (Wanting); van Koolwijk, L.M. (Leonieke); Zheng, L. (Li); Rivadeneira, F. (Fernando); Baskaran, M. (Mani); van der Lee, S.J. (Sven); Perera, S. (Shamira); de Jong, P.T. (Paulus); Oostra, B.A. (Ben); Uitterlinden, A.G. (André); Fan, Q. (Qiao); Hofman, A. (Albert); Shyong Tai, E. (E-); Vingerling, J.R. (Johannes); Sim, X. (Xueling); Wolfs, R.C. (Roger); Teo, Y.Y. (Yik Ying); Lemij, H.G. (Hans); Khor, C.C. (Chiea Chuen); Willemsen, R. (Rob); Lackner, K.J. (Karl); Aung, T. (Tin); Jansonius, N.M. (Nomdo); Montgomery, G. (Grant); Wild, P.S. (Philipp); Young, T.L. (Terri); Burdon, K.P. (Kathryn); Hysi, P.G. (Pirro); Pasquale, L.R. (Louis); Wong, T.Y. (Tien Yin); Klaver, C.C. (Caroline); Hewitt, A.W. (Alex); Jonas, J.B. (Jost); Mitchell, P. (Paul); Lotery, A.J. (Andrew); Foster, P.J. (Paul); Vitart, V. (Veronique); Pfeiffer, N. (Norbert); Craig, J.E. (Jamie); Mackey, D.A. (David); Hammond, C.J. (Christopher); Wiggs, J.L. (Janey); Cheng, C.Y. (Ching-Yu); van Duijn, C.M. (Cornelia); MacGregor, S. (Stuart)

    2017-01-01

    textabstractPrimary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We

  3. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics

    NARCIS (Netherlands)

    Springelkamp, Henriët; Iglesias, Adriana I; Mishra, Aniket; Höhn, René; Wojciechowski, Robert; Khawaja, Anthony P; Nag, Abhishek; Wang, Ya Xing; Wang, Jie Jin; Cuellar-Partida, Gabriel; Gibson, Jane; Cooke Bailey, Jessica N; Vithana, Eranga N; Gharahkhani, Puya; Boutin, Thibaud; Ramdas, Wishal D; Zeller, Tanja; Luben, Robert N; Yonova-Doing, Ekaterina; Viswanathan, Ananth C; Yazar, Seyhan; Cree, Angela J; Haines, Jonathan L; Koh, Jia Yu; Souzeau, Emmanuelle; Wilson, James F; Amin, Najaf; Müller, Christian; Venturini, Cristina; Kearns, Lisa S; Hee Kang, Jae; Consortium, Neighborhood; Tham, Yih Chung; Zhou, Tiger; van Leeuwen, Elisabeth M; Nickels, Stefan; Sanfilippo, Paul; Liao, Jiemin; Linde, Herma van der; Zhao, Wanting; van Koolwijk, Leonieke M E; Zheng, Li; Rivadeneira, Fernando; Baskaran, Mani; van der Lee, Sven J; Perera, Shamira; de Jong, Paulus T V M; Oostra, Ben A; Uitterlinden, André G; Fan, Qiao; Hofman, Albert; Shyong Tai, E-; Vingerling, Johannes R; Sim, Xueling; Wolfs, Roger C W; Teo, Yik Ying; Lemij, Hans G; Khor, Chiea Chuen; Willemsen, Rob; Lackner, Karl J; Aung, Tin; Jansonius, Nomdo M; Montgomery, Grant; Wild, Philipp S; Young, Terri L; Burdon, Kathryn P; Hysi, Pirro G; Pasquale, Louis R; Wong, Tien Yin; Klaver, Caroline C W; Hewitt, Alex W; Jonas, Jost B; Mitchell, Paul; Lotery, Andrew J; Foster, Paul J; Vitart, Veronique; Pfeiffer, Norbert; Craig, Jamie E; Mackey, David A; Hammond, Christopher J; Wiggs, Janey L; Cheng, Ching-Yu; van Duijn, Cornelia M; MacGregor, Stuart

    2017-01-01

    Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a

  4. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics

    NARCIS (Netherlands)

    Springelkamp, H.; Iglesias, A.I.; Mishra, A; Hohn, R.; Wojciechowski, R.; Khawaja, A.P.; Nag, A.; Wang, Y.X.; Wang, J.J.; Cuellar-Partida, G.; Gibson, J.; Bailey, J.N.; Vithana, E.N.; Gharahkhani, P.; Boutin, T.; Ramdas, W.D.; Zeller, T.; Luben, R.N.; Yonova-Doing, E.; Viswanathan, A.C.; Yazar, S.; Cree, A.J.; Haines, J.L.; Koh, J.Y.; Souzeau, E.; Wilson, J.F.; Amin, N.; Muller, C.; Venturini, C.; Kearns, L.S.; Kang, J.H.; Tham, Y.C.; Zhou, T.; Leeuwen, E.M. van; Nickels, S.; Sanfilippo, P.; Liao, J.; Linde, H. van der; Zhao, W.; Koolwijk, L.M. van; Zheng, L.; Rivadeneira, F.; Baskaran, M.; Lee, S.J. van der; Perera, S.; Jong, P.T.; Oostra, B.A.; Uitterlinden, A.G.; Fan, Q.; Hofman, A.; Tai, E.S.; Vingerling, J.R.; Sim, X.; Wolfs, R.C.; Teo, Y.Y.; Lemij, H.G.; Khor, C.C.; Willemsen, R.; Lackner, K.J.; Aung, T.; Jansonius, N.M.; Montgomery, G.; Wild, P.S.; Young, T.L.; Burdon, K.P.; Hysi, P.G.; Pasquale, L.R.; Wong, T.Y.; Klaver, C.C.W.; Hewitt, A.W.; Jonas, J.B.; Mitchell, P.; Lotery, A.J.; Foster, P.J.; Vitart, V.; Pfeiffer, N.; Craig, J.E.; Mackey, D.A.; Hammond, C.J.; Wiggs, J.L.; Cheng, C.Y.; Duijn, C.M. van; MacGregor, S.

    2017-01-01

    Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increased risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a

  5. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics

    NARCIS (Netherlands)

    Springelkamp, Henriët; Iglesias, Adriana I; Mishra, Aniket; Höhn, René; Wojciechowski, Robert; Khawaja, Anthony P; Nag, Abhishek; Wang, Ya Xing; Wang, Jie Jin; Cuellar-Partida, Gabriel; Gibson, Jane; Cooke Bailey, Jessica N; Vithana, Eranga N; Gharahkhani, Puya; Boutin, Thibaud; Ramdas, Wishal D; Zeller, Tanja; Luben, Robert N; Yonova-Doing, Ekaterina; Viswanathan, Ananth C; Yazar, Seyhan; Cree, Angela J; Haines, Jonathan L; Koh, Jia Yu; Souzeau, Emmanuelle; Wilson, James F; Amin, Najaf; Müller, Christian; Venturini, Cristina; Kearns, Lisa S; Hee Kang, Jae; Consortium, Neighborhood; Tham, Yih Chung; Zhou, Tiger; van Leeuwen, Elisabeth M; Nickels, Stefan; Sanfilippo, Paul; Liao, Jiemin; Linde, Herma van der; Zhao, Wanting; van Koolwijk, Leonieke M E; Zheng, Li; Rivadeneira, Fernando; Baskaran, Mani; van der Lee, Sven J; Perera, Shamira; de Jong, Paulus T V M; Oostra, Ben A; Uitterlinden, André G; Fan, Qiao; Hofman, Albert; Shyong Tai, E-; Vingerling, Johannes R; Sim, Xueling; Wolfs, Roger C W; Teo, Yik Ying; Lemij, Hans G; Khor, Chiea Chuen; Willemsen, Rob; Lackner, Karl J; Aung, Tin; Jansonius, Nomdo M; Montgomery, Grant; Wild, Philipp S; Young, Terri L; Burdon, Kathryn P; Hysi, Pirro G; Pasquale, Louis R; Wong, Tien Yin; Klaver, Caroline C W; Hewitt, Alex W; Jonas, Jost B; Mitchell, Paul; Lotery, Andrew J; Foster, Paul J; Vitart, Veronique; Pfeiffer, Norbert; Craig, Jamie E; Mackey, David A; Hammond, Christopher J; Wiggs, Janey L; Cheng, Ching-Yu; van Duijn, Cornelia M; MacGregor, Stuart

    2017-01-01

    Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genom

  6. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics.

    NARCIS (Netherlands)

    Springelkamp, H. (Henriët); Iglesias, A.I. (Adriana); Mishra, A. (Aniket); Höhn, R. (René); Wojciechowski, R. (Robert); Khawaja, A.P. (Anthony); Nag, A. (Abhishek); Wang, Y.X. (Ya Xing); Wang, J.J. (Jie Jin); Cuellar-Partida, G. (Gabriel); Gibson, J. (Jane); Cooke Bailey, J.N. (Jessica); Vithana, E.N. (Eranga); Gharahkhani, P. (Puya); Boutin, T. (Thibaud); Ramdas, W.D. (Wishal); Zeller, T. (Tanja); Luben, R.N. (Robert); Yonova-Doing, E. (Ekaterina); Viswanathan, A.C. (Ananth); Yazar, S. (Seyhan); Cree, A.J. (Angela); Haines, J.L. (Jonathan); Koh, J.Y. (Jia Yu); Souzeau, E. (Emmanuelle); Wilson, J.F. (James); Amin, N. (Najaf); Müller, C. (Christian); Venturini, C. (Cristina); Kearns, L.S. (Lisa); Hee Kang, J. (Jae); Consortium, N. (Neighborhood); Tham, Y.C. (Yih Chung); Zhou, T. (Tiger); van Leeuwen, E.M. (Elisabeth); Nickels, S. (Stefan); Sanfilippo, P. (Paul); Liao, J. (Jiemin); Linde, H.V. (Herma van der); Zhao, W. (Wanting); van Koolwijk, L.M. (Leonieke); Zheng, L. (Li); Rivadeneira, F. (Fernando); Baskaran, M. (Mani); van der Lee, S.J. (Sven); Perera, S. (Shamira); de Jong, P.T. (Paulus); Oostra, B.A. (Ben); Uitterlinden, A.G. (André); Fan, Q. (Qiao); Hofman, A. (Albert); Shyong Tai, E. (E-); Vingerling, J.R. (Johannes); Sim, X. (Xueling); Wolfs, R.C. (Roger); Teo, Y.Y. (Yik Ying); Lemij, H.G. (Hans); Khor, C.C. (Chiea Chuen); Willemsen, R. (Rob); Lackner, K.J. (Karl); Aung, T. (Tin); Jansonius, N.M. (Nomdo); Montgomery, G. (Grant); Wild, P.S. (Philipp); Young, T.L. (Terri); Burdon, K.P. (Kathryn); Hysi, P.G. (Pirro); Pasquale, L.R. (Louis); Wong, T.Y. (Tien Yin); Klaver, C.C. (Caroline); Hewitt, A.W. (Alex); Jonas, J.B. (Jost); Mitchell, P. (Paul); Lotery, A.J. (Andrew); Foster, P.J. (Paul); Vitart, V. (Veronique); Pfeiffer, N. (Norbert); Craig, J.E. (Jamie); Mackey, D.A. (David); Hammond, C.J. (Christopher); Wiggs, J.L. (Janey); Cheng, C.Y. (Ching-Yu); van Duijn, C.M. (Cornelia); MacGregor, S. (Stuart)

    2017-01-01

    textabstractPrimary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We condu

  7. A forward-angle-scattering method for the determination of optical constants and particle size distribution by collimated laser irradiation

    Science.gov (United States)

    Ren, Yatao; Qi, Hong; Yu, Xiaoying; Ruan, Liming

    2017-04-01

    This study examined the feasibility of using a secondary optimization technique and forward-angle-scattering method to retrieve optical constants (or complex refractive indices) and particle size distribution (PSD) simultaneously. In this work, two continuous wave lasers of different wavelengths were applied to irradiate the participating samples, and the scattered light of samples with different acceptance angles was obtained. First, the scattered signals within different acceptance angles were calculated by solving the radiative transfer equation. Then, the complex refractive index and PSD were retrieved simultaneously by applying quantum particle swarm optimization. However, the estimated results of PSD were inaccurate. Thus, a secondary optimization, which using the directional radiative intensity as input, was performed to improve the accuracy of PSD based on the first optimization process. Four commonly used kinds of monomodal PSD functions, i.e., the Rosin-Rammler, standard Normal, Logarithmic Normal, and Junge distribution, were retrieved. All results showed that the proposed technique can estimate the complex refractive index and PSD accurately.

  8. Multifrequency Excitation of a Clamped-Clamped Microbeam

    KAUST Repository

    Jaber, Nizar R.

    2016-01-20

    We present analytical and experimental investigation of an electrically actuated clamped-clamped microbeam under a twosource harmonic excitation. The first frequency is swept around the first mode of vibration where the second one is fixed. These microbeams are fabricated using polyimide as structural layer coated with nickel form top and chromium and gold layers from bottom. We demonstrate the excitation of additive and subtractive type resonance. We show that by properly tuning the frequency and the amplitude of the excitation force, the frequency bandwidth of the resonator is increased. Theoretically, we solved the eigenvalue problem for different axial forces to find the natural frequencies ratio that match the experimental values. Using Galerkin method, a reduced order model is derived to simulate the static and dynamic response of the device where using three symmetric mode shapes provided a good agreement with experimental data. © Copyright 2015 by ASME.

  9. Post-buckling and mode jumping analysis of clamped supported composite laminates with antisymmetric angle-ply under bi-axial compressive load%双轴受压反对称角铺设复合材料层合板在固支边界下的后屈曲和模态跃迁

    Institute of Scientific and Technical Information of China (English)

    钟轶峰; 张亮亮

    2011-01-01

    The governing partial differential equations (PDEs) were deduced from the asymptotically correct geometrically nonlinear theory to research the buckling and mode jumping behavior of clamped supported composite laminates with antisymmetric angle- ply under bi - axial compressive load. The two coupled fourth - order partial differential equations (PDEs), namely, the compatibility equation and the dynamic governing equation were transformed into a system of nonlinear ordinary differential equations (ODEs). Then a relatively simpler solution method was developed. The generalized Galerkin method was used to solve boundary value problems corresponding to antisymmetric angle-ply composite plates. The post-buckling patterns with different complexity before and after mode jumping were analyzed. An numerical example of 4- layers clamped composite laminates shows that the numerical results in the primary post-buckling region from the present method agree well with the finite element analysis (FEA). The FEA may lose its convergence when solution comes close the secondary point, while the analytic method can explore deeply into the post-buckling realm and accuratty capture the mode jumping phenomenon. Only the pure symmetric modes may be used to qualitatively predict the primary post- buckling branch, the secondary bifurcation load and the remote jumped branch of the composite laminates with antisymmetric angle-ply.%为有效分析双轴受压反对称角铺设复合材料层压板在固支边界下的后屈曲性能,由渐近修正几何非线性理论推导其双耦合四阶偏微分方程(即应变协调方程和稳定性控制方程),通过双Fourier级数将耦合非线性控制偏微分方程转换为系列非线性常微分方程,从而获得相对简单的求解方法。使用广义Galerkin方法求解与角交铺设复合层合板相关的边界值问题,研究了模态跃迁前后不同复杂程度的后屈曲模式。对四层固支边界

  10. Nonlinear Optical Properties of Azo Dye Monolayers : The Effect of Tilt Angle on the Local Field

    NARCIS (Netherlands)

    Cnossen, Gerard; Drabe, Karel E.; Wiersma, Douwe A.; Schoondorp, Monique A.; Schouten, Arend Jan; Hulshof, Johannes; Feringa, Ben L.

    1993-01-01

    We report on the second-order nonlinear optical susceptibility chi(2)(2omega,omega,omega) of dye-doped Langmuir-Blodgett monolayers. Chi(2) is found to exhibit a nonlinear dependence on surface density, which is attributed to microscopic local-fields. In order to calculate the microscopic local-fiel

  11. The optical scattering property: spatial and angle variability in Northern South China Sea

    Science.gov (United States)

    Li, Cai; Cao, Wenxi; Yang, Yuezhong; Xu, Zhantang

    2015-02-01

    Observations are presented of the Volume scattering function (VSF) over the angular interval 20 to 160°, to maximum depth of about 90m in the Northern South China Sea in Case I and Case II waters. The observations were collected by using a self-developed in situ scattering instrument, which synchronously measured the attenuation coefficient, the VSFs in seven angles between 20 to 160° at 650nm, and the sea depths. General, the VSFs show a strong scattering in the forward, a broad scattering minimum in the scattering angular interval 90 to 126° and a weak increase in the rest of backward scattering angles. The analysis of the in situ data also indicates that the magnitude and the shape of the VSF change with areas and profile depths. From Case II to Case I, the forward scattering in 20°, which is mainly due to relatively large suspended particles, varied about three orders magnitude with highest values observed in Case II waters. In Case I waters, form the surface layer to the deeper layer, the magnitude of the VSFs firstly decreased with the depth, and then increased with the depth until reached a maximum scattering layer between 30 to 50m, and then decreased with depth until reached the maximum measurement depth. In Case II waters, the vertical profile distributions of VSF are complex, but in almost all profile, the magnitude of the VSFs firstly decreased with the depth, and then increased with the depth until reached the maximum measurement depth. The result of analysis also showed that in almost all of these stations, in the surface water, based on the light scattering by bubbles at shallow depths, the angle scattering at 60º-80º has a significant "shoulder", and the wind plays a key role in the bubble scattering.

  12. 用于人体关节角度捕捉的光纤角度传感器的研究%Research on Fiber-optic Angle Sensor with Capturing Human Joint Angles

    Institute of Scientific and Technical Information of China (English)

    张振海; 张小栋; 侯育军

    2012-01-01

    在分析现有的外骨骼机器人控制信号的拾取方法优缺点的基础上,设计了一种用于捕捉人体关节角度的光纤角度传感器.通过结构设计和理论分析,建立光纤输出端光功率与关节弯曲角度的数学模型.仿真结果表明,所设计的传感器输出信号对关节角度具有很好的线性度,可用于外骨骼机器人的角度控制的信号捕捉.%After analyzing the adavantages and disadvantages of the approaches for exoskeleton robot to collect control signal, a fiber-optic angle sensor was designed to capture human joint angles. Through structural design and theoretical analysis , the mathematical model of the output optical power and joint angles are established. Simulation results show that the fiber-optic angle sensor has good linearity, and can be used to the exoskeleton robot for capturing the human joint angles.

  13. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    OpenAIRE

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-01-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, m...

  14. An optical fiber Fabry-Perot pressure sensor using corrugated diaphragm and angle polished fiber

    Science.gov (United States)

    Zhu, Jiali; Wang, Ming; Chen, Lu; Ni, Xiaoqi; Ni, Haibin

    2017-03-01

    In this paper, a Fabry-Perot pressure sensor using a corrugated diaphragm and angle polished fiber is proposed. A SU-8 structure using two step of lithography is formed to fix the polished fiber, which helps control the cavity length precisely. The fabrication process is described. The characteristics of both pressure and temperature are tested. Also the temperature compensation is realized. Experimental results show that the sensor has high sensitivity and good linearity over the pressure range of 0-0.1 MPa. The sensitivity (change in cavity/loaded pressure) is 705.64 μm/MPa.

  15. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    OpenAIRE

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-01-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, m...

  16. A hemispherical, high-solid-angle optical micro-cavity for cavity-QED studies

    OpenAIRE

    Cui, Guoqiang; Hannigan, J. M.; Loeckenhoff, R.; Matinaga, F. M.; Raymer, M. G.; Bhongale, S.; Holland, M.; Mosor, S.; Chatterjee, S.; Gibbs, H. M.; Khitrova, G.

    2006-01-01

    We report a novel hemispherical micro-cavity that is comprised of a planar integrated semiconductor distributed Bragg reflector (DBR) mirror, and an external, concave micro-mirror having a radius of curvature $50\\mathrm{\\mu m}$. The integrated DBR mirror containing quantum dots (QD), is designed to locate the QDs at an antinode of the field in order to maximize the interaction between the QD and the cavity. The concave micro-mirror, with high-reflectivity over a large solid-angle, creates a d...

  17. A wide angle view imaging diagnostic with all reflective, in-vessel optics at JET

    Energy Technology Data Exchange (ETDEWEB)

    Clever, M. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, 52425 Jülich (Germany); Arnoux, G.; Balshaw, N. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Garcia-Sanchez, P. [Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, Madrid (Spain); Patel, K. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Sergienko, G. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, 52425 Jülich (Germany); Soler, D. [Winlight System, 135 rue Benjamin Franklin, ZA Saint Martin, F-84120 Pertuis (France); Stamp, M.F.; Williams, J.; Zastrow, K.-D. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2013-10-15

    Highlights: ► A new wide angle view camera system has been installed at JET. ► The system helps to protect the ITER-like wall plasma facing components from damage. ► The coverage of the vessel by camera observation systems was increased. ► The system comprises an in-vessel part with parabolic and flat mirrors. ► The required image quality for plasma monitoring and wall protection was delivered. -- Abstract: A new wide angle view camera system has been installed at JET in preparation for the ITER-like wall campaigns. It considerably increases the coverage of the vessel by camera observation systems and thereby helps to protect the – compared to carbon – more fragile plasma facing components from damage. The system comprises an in-vessel part with parabolic and flat mirrors and an ex-vessel part with beam splitters, lenses and cameras. The system delivered the image quality required for plasma monitoring and wall protection.

  18. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    Science.gov (United States)

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-09-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (pmeasurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

  19. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion.

    Science.gov (United States)

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-09-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (pmeasurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

  20. Analysis list: Clamp [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Clamp Cell line + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Clamp.1....tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Clamp.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/Clam...p.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Clamp.Cell_line.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Cell_line.gml ...

  1. Glancing Angle Deposition System for Advanced Fabrication of Metamaterial and Transformation-Optics Devices

    Science.gov (United States)

    2012-06-15

    CLASSIFICATION OF: Transformation optics is opening the door to new devices and applications by manipulating the flow of light on the nano-scale combining...quote received from vendor ( PVD  Products)  ­ 01/16/2011: Utility form received for pre‐installation connections  ­ 05/13/2011: Trades (plumber

  2. A hemispherical, high-solid-angle optical micro-cavity for cavity-QED studies

    Science.gov (United States)

    Cui, Guoqiang; Hannigan, J. M.; Loeckenhoff, R.; Matinaga, F. M.; Raymer, M. G.; Bhongale, S.; Holland, M.; Mosor, S.; Chatterjee, S.; Gibbs, H. M.; Khitrova, G.

    2006-03-01

    We report a novel hemispherical micro-cavity that is comprised of a planar integrated semiconductor distributed Bragg reflector (DBR) mirror, and an external, concave micro-mirror having a radius of curvature 50 µm. The integrated DBR mirror containing quantum dots (QD), is designed to locate the QDs at an antinode of the field in order to maximize the interaction between the QD and cavity. The concave micro-mirror, with high-reflectivity over a large solid-angle, creates a diffraction-limited (sub-micron) mode-waist at the planar mirror, leading to a large coupling constant between the cavity mode and QD. The half-monolithic design gives more spatial and spectral tuning abilities, relatively to fully monolithic structures. This unique micro-cavity design will potentially enable us to both reach the cavity quantum electrodynamics (QED) strong coupling regime and realize the deterministic generation of single photons on demand.

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

    Science.gov (United States)

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

    2017-03-20

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

  4. Delayed umbilical cord clamping in premature neonates.

    Science.gov (United States)

    Kaempf, Joseph W; Tomlinson, Mark W; Kaempf, Andrew J; Wu, YingXing; Wang, Lian; Tipping, Nicole; Grunkemeier, Gary

    2012-08-01

    Delayed umbilical cord clamping is reported to increase neonatal blood volume. We estimated the clinical outcomes in premature neonates who had delayed umbilical cord clamping compared with a similar group who had early umbilical cord clamping. This was a before-after investigation comparing early umbilical cord clamping with delayed umbilical cord clamping (45 seconds) in two groups of singleton neonates, very low birth weight (VLBW) (401-1,500 g) and low birth weight (LBW) (greater than 1,500 g but less than 35 weeks gestation). Neonates were excluded from delayed umbilical cord clamping if they needed immediate major resuscitation. Primary outcomes were provision of delivery room resuscitation, hematocrit, red cell transfusions, and the principle Vermont Oxford Network outcomes. In VLBW neonates (77 delayed umbilical cord clamping, birth weight [mean±standard deviation] 1,099±266 g; 77 early umbilical cord clamping 1,058±289 g), delayed umbilical cord clamping was associated with less delivery room resuscitation, higher Apgar scores at 1 minute, and higher hematocrit. Delayed umbilical cord clamping was not associated with significant differences in the overall transfusion rate, peak bilirubin, any of the principle Vermont Oxford Network outcomes, or mortality. In LBW neonates (172 delayed umbilical cord clamping, birth weight [mean±standard deviation] 2,159±384 g; 172 early umbilical cord clamping 2,203±447 g), delayed umbilical cord clamping was associated with higher hematocrit and was not associated with a change in delivery room resuscitation or Apgar scores or with changes in the transfusion rate or peak bilirubin. Regression analysis showed increasing gestational age and birth weight and delayed umbilical cord clamping were the best predictors of higher hematocrit and less delivery room resuscitation. Delayed umbilical cord clamping can safely be performed in singleton premature neonates and is associated with a higher hematocrit, less delivery room

  5. Importance of backbone angles versus amino acid configurations in peptide vibrational Raman optical activity spectra

    Science.gov (United States)

    Herrmann, Carmen; Ruud, Kenneth; Reiher, Markus

    2008-01-01

    In this work, we investigate whether the differential scattering of right- and left-circularly polarized light in peptide Raman optical activity spectra are uniquely dominated by the backbone conformation, or whether the configurations of the individual amino acid also play a significant role. This is achieved by calculating Raman optical activity spectra using density functional theory for four structurally related peptides with a common backbone conformation, but with different sequences of amino acid configurations. Furthermore, the ROA signals of the amide normal modes are decomposed into contributions from groups of individual atoms. It is found that the amino acid configuration has a considerable influence on the ROA peaks in the amide I, II, and III regions, although the local decomposition reveals that the side-chain atoms only contribute to those peaks directly in the case of the amide II vibrations. Furthermore, small changes in the amide normal modes may lead to large and irregular modifications in the ROA intensity differences, making it difficult to establish transferable ROA intensity differences even for structurally similar vibrations.

  6. At-line bioprocess monitoring by immunoassay with rotationally controlled serial siphoning and integrated supercritical angle fluorescence optics

    Energy Technology Data Exchange (ETDEWEB)

    Nwankire, Charles E., E-mail: charles.nwankire@dcu.ie [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Donohoe, Gerard G.; Zhang, Xin [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Biotechnology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Siegrist, Jonathan [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Somers, Martin [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); Kurzbuch, Dirk [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Monaghan, Ruairi [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); Kitsara, Maria [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Burger, Robert [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Hearty, Stephen [Biomedical Diagnostics Institute, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Biotechnology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Murrell, Julie; Martin, Christopher; Rook, Martha [EMD Millipore Corporation, 80 Ashby Road, Bedford, MA (United States); and others

    2013-06-05

    Graphical abstract: A serial siphon based centrifugal microfluidic platform for the quantitative at-line monitoring of human immunoglobulin G (hIgG) in typical industrial bioprocess samples using a prototype optical SAF detection system. -- Highlights: •Sample-to-answer microfluidic lab-on-a-disc device for at-line bioprocess monitoring. •Centrifugally integrated and automated reagent delivery by serial-siphon valves. •Supercritical angle fluorescence optics embedded on centrifugal platform. •Development of fluorescence-linked-immunosorbent assay on human immunoglobulin G. •Bioprocess samples from industrial reactor determined on the prototype system. -- Abstract: In this paper we report a centrifugal microfluidic “lab-on-a-disc” system for at-line monitoring of human immunoglobulin G (hIgG) in a typical bioprocess environment. The novelty of this device is the combination of a heterogeneous sandwich immunoassay on a serial siphon-enabled microfluidic disc with automated sequential reagent delivery and surface-confined supercritical angle fluorescence (SAF)-based detection. The device, which is compact, easy-to-use and inexpensive, enables rapid detection of hIgG from a bioprocess sample. This was achieved with, an injection moulded SAF lens that was functionalized with aminopropyltriethoxysilane (APTES) using plasma enhanced chemical vapour deposition (PECVD) for the immobilization of protein A, and a hybrid integration with a microfluidic disc substrate. Advanced flow control, including the time-sequenced release of on-board liquid reagents, was implemented by serial siphoning with ancillary capillary stops. The concentration of surfactant in each assay reagent was optimized to ensure proper functioning of the siphon-based flow control. The entire automated microfluidic assay process is completed in less than 30 min. The developed prototype system was used to accurately measure industrial bioprocess samples that contained 10 mg mL{sup −1} of hIgG.

  7. Rotation of the optical polarization angle associated with the 2008 γ-ray flare of blazar W Comae

    Energy Technology Data Exchange (ETDEWEB)

    Sorcia, Marco; Benítez, Erika; Cabrera, José I. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. 70-264, Mexico D.F., 04510 (Mexico); Hiriart, David; López, José M. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. 810, Ensenada, B.C., 22800 (Mexico); Mújica, Raúl [Instituto Nacional de Astrofísica, Óptica y Electrónica, Apdo. Postal 51 y 216, 72000 Tonantzintla, Puebla (Mexico)

    2014-10-10

    An R-band photopolarimetric variability analysis of the TeV bright blazar W Comae between 2008 February 28 and 2013 May 17 is presented. The source showed a gradual tendency to decrease its mean flux level with a total change of 3 mJy. A maximum and minimum brightness states in the R band of 14.25 ± 0.04 and 16.52 ± 0.1 mag, respectively, were observed, corresponding to a maximum variation of ΔF = 5.40 mJy. We estimated a minimum variability timescale of Δt = 3.3 days. A maximum polarization degree P = 33.8% ± 1.6%, with a maximum variation of ΔP = 33.2%, was found. One of our main results is the detection of a large rotation of the polarization angle from 78° to 315° (Δθ ∼ 237°) that coincides in time with the γ-ray flare observed in 2008 June. This result indicates that both optical and γ-ray emission regions could be co-spatial. During this flare, a correlation between the R-band flux and polarization degree was found with a correlation coefficient of r {sub F} {sub –} {sub p} = 0.93 ± 0.11. From the Stokes parameters, we infer the existence of two optically thin synchrotron components that contribute to the polarized flux. One of them is stable with a constant polarization degree of 11%. Assuming a shock-in jet model during the 2008 flare, we estimated a maximum Doppler factor δ {sub D} ∼ 27 and a minimum of δ {sub D} ∼ 16; a minimum viewing angle of the jet ∼2.°0; and a magnetic field B ∼ 0.12 G.

  8. Choroidal thickness in primary angle-closure glaucoma: the results of Measurement by Means of Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    N. I. Kurysheva

    2013-01-01

    Full Text Available Purpose: to compare сhoroidal thickness (CT in primary angle-closure glaucoma (PACG and primary open angle glaucoma (POAG.Methods: сhoroidal thickness was evaluated in 30 patients (30 eyes with PACG, 30 patients (30 eyes with POAG and 30 control subjects by means of optical coherence tomography (RTVue-100 OCT, Optovue, Inc., Fremont, CA in fovea (CTf and in peripapillary region (CTp. Patients in both groups were well matched for glaucoma stage (MD 1,46±1,73 dB in POAG and –1,89±2,34 dB in PACG, p = 0,44 and age: 70,0±6,64 in POAG and 68,0 ±4,68 in PACG (p = 0,29.Results revealed a statistically significant increase of CT in PACG patients in comparison to POAG: 372,81±126,83 μm and 251,25±79,56 μm (p = 0,002, respectively for CTf, and 204,56±115,9 μm and 29,0±61,48 μm (p = 0,03, respectively for CTp.Conclusion: Increased CT might be another anatomic characteristic of AC eyes. These findings may support the hypotheses that choroidal expansion is a contributing factor to the development of AC disease.

  9. Choroidal thickness in primary angle-closure glaucoma: the results of Measurement by Means of Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    N. I. Kurysheva

    2014-07-01

    Full Text Available Purpose: to compare сhoroidal thickness (CT in primary angle-closure glaucoma (PACG and primary open angle glaucoma (POAG.Methods: сhoroidal thickness was evaluated in 30 patients (30 eyes with PACG, 30 patients (30 eyes with POAG and 30 control subjects by means of optical coherence tomography (RTVue-100 OCT, Optovue, Inc., Fremont, CA in fovea (CTf and in peripapillary region (CTp. Patients in both groups were well matched for glaucoma stage (MD 1,46±1,73 dB in POAG and –1,89±2,34 dB in PACG, p = 0,44 and age: 70,0±6,64 in POAG and 68,0 ±4,68 in PACG (p = 0,29.Results revealed a statistically significant increase of CT in PACG patients in comparison to POAG: 372,81±126,83 μm and 251,25±79,56 μm (p = 0,002, respectively for CTf, and 204,56±115,9 μm and 29,0±61,48 μm (p = 0,03, respectively for CTp.Conclusion: Increased CT might be another anatomic characteristic of AC eyes. These findings may support the hypotheses that choroidal expansion is a contributing factor to the development of AC disease.

  10. Loading dynamics of a sliding DNA clamp.

    KAUST Repository

    Cho, Won-Ki

    2014-05-22

    Sliding DNA clamps are loaded at a ss/dsDNA junction by a clamp loader that depends on ATP binding for clamp opening. Sequential ATP hydrolysis results in closure of the clamp so that it completely encircles and diffuses on dsDNA. We followed events during loading of an E. coli β clamp in real time by using single-molecule FRET (smFRET). Three successive FRET states were retained for 0.3 s, 0.7 s, and 9 min: Hydrolysis of the first ATP molecule by the γ clamp loader resulted in closure of the clamp in 0.3 s, and after 0.7 s in the closed conformation, the clamp was released to diffuse on the dsDNA for at least 9 min. An additional single-molecule polarization study revealed that the interfacial domain of the clamp rotated in plane by approximately 8° during clamp closure. The single-molecule polarization and FRET studies thus revealed the real-time dynamics of the ATP-hydrolysis-dependent 3D conformational change of the β clamp during loading at a ss/dsDNA junction.

  11. The RFC clamp loader: structure and function.

    Science.gov (United States)

    Yao, Nina Y; O'Donnell, Mike

    2012-01-01

    The eukaryotic RFC clamp loader couples the energy of ATP hydrolysis to open and close the circular PCNA sliding clamp onto primed sites for use by DNA polymerases and repair factors. Structural studies reveal clamp loaders to be heteropentamers. Each subunit contains a region of homology to AAA+ proteins that defines two domains. The AAA+ domains form a right-handed spiral upon binding ATP. This spiral arrangement generates a DNA binding site within the center of RFC. DNA enters the central chamber through a gap between the AAA+ domains of two subunits. Specificity for a primed template junction is achieved by a third domain that blocks DNA, forcing it to bend sharply. Thus only DNA with a flexible joint can bind the central chamber. DNA entry also requires a slot in the PCNA clamp, which is opened upon binding the AAA+ domains of the clamp loader. ATP hydrolysis enables clamp closing and ejection of RFC, completing the clamp loading reaction.

  12. Optic-electronic systems for measuring angle deformations of a fully rotateable radiotelescope

    Energy Technology Data Exchange (ETDEWEB)

    Konyakhin, I A; Timofeev, A N; Vorona, A M [Department. of Optic-electronics Devices and Systems, Saint-Petersburg State University of Information Technologies, Mechanics and Optics, 49 Kronverksky Avenue, St. Petersburg, 197101 (Russian Federation)

    2007-07-15

    The construction of new large radio telescope RT-70 Suffa requires controlling the element angular deformation. Following issues dealing with this problem are described in this article: 1) the possibility of the design of deformation measurement system based on autoreflection scheme, 2) the new vignetting error compensation method. The great attention during the research was paid to the experimental approval of the theoretical results. The model of the described system had the following characteristics: infrared emission diode AL107B by power 15 mWt as sources of radiation; the focal length of receiver objective by the focal length 500 mm as aperture of receiver videocamera, the CMOS matrix receiver by type OV05610 Color CMOS QSXGA with 2592 * 1944 pixels and one pixel size (2.8 * 2.8) {mu}m{sup 2} produced OmniVision as image analyzer. The experimental error measurement was 1.5 arc seconds at the angular range 20 arc. minutes, that allows measure the angle deformation of radiotelescope with the mirror diameter 70 m.

  13. Association of Myopic Deformation of Optic Disc with Visual Field Progression in Paired Eyes with Open-Angle Glaucoma

    Science.gov (United States)

    Hangai, Masanori; Ishikawa, Makoto; Yoshitomi, Takeshi

    2017-01-01

    Purpose The influence of myopia on glaucoma progression remains unknown, possibly because of the multifactorial nature of glaucoma and difficulty in assessing a solo contribution of myopia. The purpose of this study is to investigate the association of myopia with visual field (VF) progression in glaucoma using a paired-eye design to minimize the influence of confounding systemic factors that are diverse among individuals. Methods This retrospective study evaluated 144 eyes of 72 subjects with open-angle glaucoma, with similar intra-ocular pressure between paired eyes, spherical equivalent (SE) ≤ -2 diopter (D), and axial length ≥ 24 mm. Paired eyes with faster and slower VF progression were grouped separately, according to the global VF progression rate assessed by automated pointwise linear regression analysis. The SE, axial length, tilt ratio and torsion angle of optic discs, Bruch’s membrane (BM) opening area, and gamma zone parapapillary atrophy (PPA) width were compared between the two groups. Factors associated with faster VF progression were determined by logistic regression analysis. Results The mean follow-up duration was 8.9 ± 4.4 years. The mean value of SE and axial length were -6.31 ± 1.88 D and 26.05 ± 1.12 mm, respectively. The mean global visual field progression rate was -0.32 ± 0.38 dB/y. Tilt ratio, BM opening area, and gamma zone PPA width were significantly greater in the eyes with faster VF progression than those with slower progression. In multivariate analysis, these factors were significantly associated with faster VF progression (all P < 0.05), while SE and axial length were not associated with it. Conclusion In myopic glaucoma subjects, tilt of the optic disc and temporal shifting and enlargement of the BM opening were associated with faster rate of VF progression between paired eyes. This suggests that myopia influences VF progression in glaucomatous eyes via optic disc deformations rather than via refractive error itself

  14. How Does Patch Clamp Work?--An easy approach to understanding patch clamp mechanism

    Institute of Scientific and Technical Information of China (English)

    关兵才; 李之望

    2003-01-01

    In order to help patch clamp users,most of whom are not good enough at electrics and electronics,to understandthe complicated principles of patch clamp technique,we present a readily accessible explanation of patch clamp mechanism,in-cluding basic analysis of membrane currents under voltage clamp,achievement of voltage clamp and current recording,capaci-tance compensation,series resistance compensation,voltage offset correction,leak subtraction and current clamp,based on ourworking and teaching experience and with the aid of some useful formulae.

  15. Measurement of Systemic Mitochondrial Function in Advanced Primary Open-Angle Glaucoma and Leber Hereditary Optic Neuropathy.

    Directory of Open Access Journals (Sweden)

    Nicole J Van Bergen

    Full Text Available Primary Open Angle Glaucoma (POAG is a common neurodegenerative disease characterized by the selective and gradual loss of retinal ganglion cells (RGCs. Aging and increased intraocular pressure (IOP are glaucoma risk factors; nevertheless patients deteriorate at all levels of IOP, implying other causative factors. Recent evidence presents mitochondrial oxidative phosphorylation (OXPHOS complex-I impairments in POAG. Leber Hereditary Optic Neuropathy (LHON patients suffer specific and rapid loss of RGCs, predominantly in young adult males, due to complex-I mutations in the mitochondrial genome. This study directly compares the degree of OXPHOS impairment in POAG and LHON patients, testing the hypothesis that the milder clinical disease in POAG is due to a milder complex-I impairment. To assess overall mitochondrial capacity, cells can be forced to produce ATP primarily from mitochondrial OXPHOS by switching the media carbon source to galactose. Under these conditions POAG lymphoblasts grew 1.47 times slower than controls, whilst LHON lymphoblasts demonstrated a greater degree of growth impairment (2.35 times slower. Complex-I enzyme specific activity was reduced by 18% in POAG lymphoblasts and by 29% in LHON lymphoblasts. We also assessed complex-I ATP synthesis, which was 19% decreased in POAG patients and 17% decreased in LHON patients. This study demonstrates both POAG and LHON lymphoblasts have impaired complex-I, and in the majority of aspects the functional defects in POAG were milder than LHON, which could reflect the milder disease development of POAG. This new evidence places POAG in the spectrum of mitochondrial optic neuropathies and raises the possibility for new therapeutic targets aimed at improving mitochondrial function.

  16. Measurement of Systemic Mitochondrial Function in Advanced Primary Open-Angle Glaucoma and Leber Hereditary Optic Neuropathy.

    Science.gov (United States)

    Van Bergen, Nicole J; Crowston, Jonathan G; Craig, Jamie E; Burdon, Kathryn P; Kearns, Lisa S; Sharma, Shiwani; Hewitt, Alex W; Mackey, David A; Trounce, Ian A

    2015-01-01

    Primary Open Angle Glaucoma (POAG) is a common neurodegenerative disease characterized by the selective and gradual loss of retinal ganglion cells (RGCs). Aging and increased intraocular pressure (IOP) are glaucoma risk factors; nevertheless patients deteriorate at all levels of IOP, implying other causative factors. Recent evidence presents mitochondrial oxidative phosphorylation (OXPHOS) complex-I impairments in POAG. Leber Hereditary Optic Neuropathy (LHON) patients suffer specific and rapid loss of RGCs, predominantly in young adult males, due to complex-I mutations in the mitochondrial genome. This study directly compares the degree of OXPHOS impairment in POAG and LHON patients, testing the hypothesis that the milder clinical disease in POAG is due to a milder complex-I impairment. To assess overall mitochondrial capacity, cells can be forced to produce ATP primarily from mitochondrial OXPHOS by switching the media carbon source to galactose. Under these conditions POAG lymphoblasts grew 1.47 times slower than controls, whilst LHON lymphoblasts demonstrated a greater degree of growth impairment (2.35 times slower). Complex-I enzyme specific activity was reduced by 18% in POAG lymphoblasts and by 29% in LHON lymphoblasts. We also assessed complex-I ATP synthesis, which was 19% decreased in POAG patients and 17% decreased in LHON patients. This study demonstrates both POAG and LHON lymphoblasts have impaired complex-I, and in the majority of aspects the functional defects in POAG were milder than LHON, which could reflect the milder disease development of POAG. This new evidence places POAG in the spectrum of mitochondrial optic neuropathies and raises the possibility for new therapeutic targets aimed at improving mitochondrial function.

  17. Measurement of Systemic Mitochondrial Function in Advanced Primary Open-Angle Glaucoma and Leber Hereditary Optic Neuropathy

    Science.gov (United States)

    Van Bergen, Nicole J; Crowston, Jonathan G.; Craig, Jamie E.; Burdon, Kathryn P.; Kearns, Lisa S.; Sharma, Shiwani; Hewitt, Alex W.; Mackey, David A.; Trounce, Ian A.

    2015-01-01

    Primary Open Angle Glaucoma (POAG) is a common neurodegenerative disease characterized by the selective and gradual loss of retinal ganglion cells (RGCs). Aging and increased intraocular pressure (IOP) are glaucoma risk factors; nevertheless patients deteriorate at all levels of IOP, implying other causative factors. Recent evidence presents mitochondrial oxidative phosphorylation (OXPHOS) complex-I impairments in POAG. Leber Hereditary Optic Neuropathy (LHON) patients suffer specific and rapid loss of RGCs, predominantly in young adult males, due to complex-I mutations in the mitochondrial genome. This study directly compares the degree of OXPHOS impairment in POAG and LHON patients, testing the hypothesis that the milder clinical disease in POAG is due to a milder complex-I impairment. To assess overall mitochondrial capacity, cells can be forced to produce ATP primarily from mitochondrial OXPHOS by switching the media carbon source to galactose. Under these conditions POAG lymphoblasts grew 1.47 times slower than controls, whilst LHON lymphoblasts demonstrated a greater degree of growth impairment (2.35 times slower). Complex-I enzyme specific activity was reduced by 18% in POAG lymphoblasts and by 29% in LHON lymphoblasts. We also assessed complex-I ATP synthesis, which was 19% decreased in POAG patients and 17% decreased in LHON patients. This study demonstrates both POAG and LHON lymphoblasts have impaired complex-I, and in the majority of aspects the functional defects in POAG were milder than LHON, which could reflect the milder disease development of POAG. This new evidence places POAG in the spectrum of mitochondrial optic neuropathies and raises the possibility for new therapeutic targets aimed at improving mitochondrial function. PMID:26496696

  18. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics.

    OpenAIRE

    Springelkamp, H.; Iglesias, A. I.; A.; Mishra; Höhn, R; Wojciechowski, R.; Khawaja, A.P. (Anthony); Nag, A.; Wang, Y.X.; Wang, J. J.; Cuellar-Partida, G.; Gibson, J.; Cooke Bailey, J.N. (Jessica); Vithana, E. N.; Gharahkhani, P.; Boutin, T.

    2017-01-01

    textabstractPrimary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genome-wide association meta-analysis of IOP and optic disc parameters and validated our findings in multiple sets of POAG cases and controls. Using imputation to the 1000 genomes (1000G) re...

  19. Optic nerve head slope-based quantitative parameters for identifying open-angle glaucoma on SPECTRALIS OCT images.

    Science.gov (United States)

    Al-Hinnawi, Abdel-Razzak M; Al-Naami, Bassam O; Al-Latayfeh, Motasem M

    2017-08-01

    To investigate monitoring slope-based features of the optic nerve head (ONH) cup as open-angle glaucoma (OAG) occurs. A dataset of 46 retrospective OCT cases was acquired from the SPECTRALIS Heidelberg Engineering OCT device. A set of five parameters, which are based on the ONH cup-incline, are measured on the OAG and normal subjects in the dataset. Then, three new ONH cup-shape indices were deduced. The ONH cup-incline parameters and ONH cup-shape indices are analyzed to estimate their clinical value. The statistical difference between measurements on normal and glaucoma eyes was remarkably significant for all of the analyzed parameters and indices (p value < 0.001). The geometric shape of the ONH cup can be transferred to numerical parameters and indices. The proposed ONH cup-incline parameters and ONH cup-shape indices have shown suggestive clinical value to identify the development of OAG. As OAG appears, the top ONH cup-incline parameters decrease while the bottom ONH cup-incline parameters increase. The ONH cup-shape indices suggest capability to discriminate OAG from normal eyes.

  20. Electrostatic clamp manufactured by novel method

    NARCIS (Netherlands)

    Sligte, E. te; Storm, A.; Koster, N.B.

    2011-01-01

    Electrostatic clamps (ESCs), used in reticle and wafer handling, are presently manufactured using glass bonding and polishing technologies. We present a patented alternative concept to this process, relying on coating and etching processes rather than bonding. We manufactured a first prototype clamp

  1. 21 CFR 870.4450 - Vascular clamp.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vascular clamp. 870.4450 Section 870.4450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Surgical Devices § 870.4450 Vascular clamp. (a) Identification. A vascular...

  2. Time to implement delayed cord clamping.

    Science.gov (United States)

    McAdams, Ryan M

    2014-03-01

    Immediate umbilical cord clamping after delivery is routine in the United States despite little evidence to support this practice. Numerous trials in both term and preterm neonates have demonstrated the safety and benefit of delayed cord clamping. In premature neonates, delayed cord clamping has been shown to stabilize transitional circulation, lessening needs for inotropic medications and reducing blood transfusions, necrotizing enterocolitis, and intraventricular hemorrhage. In term neonates, delayed cord clamping has been associated with decreased iron-deficient anemia and increased iron stores with potential valuable effects that extend beyond the newborn period, including improvements in long-term neurodevelopment. The failure to more broadly implement delayed cord clamping in neonates ignores published benefits of increased placental blood transfusion at birth and may represent an unnecessary harm for vulnerable neonates.

  3. Peripapillary retinal vessel density in eyes with acute primary angle closure: an optical coherence tomography angiography study.

    Science.gov (United States)

    Wang, Xiaolei; Jiang, Chunhui; Kong, Xiangmei; Yu, Xiaobo; Sun, Xinghuai

    2017-05-01

    The purpose was to investigate peripapillary retinal vessel density in resolved acute primary angle closure (APAC) eyes. This was a prospective, cross-sectional observational study. Thirty-four eyes of 34 patients with unilateral APAC were included, together with the fellow eyes with primary angle closure suspect (PACS) as controls. Peripapillary retinal vessel density was measured using optical coherence tomography (OCT) angiography. Peripapillary retinal vessel density was compared in both eyes and the potential relationship with visual field (VF) test results was evaluated. After an acute attack, the peripapillary retinal vessel density was lower in the APAC than in the PACS eyes (79.3 ± 8.2 versus 85.6 ± 4.9, respectively; P = 0.001). The VF mean deviation (MD) (-7.7 ± 6.7 versus -3.3 ± 1.8 dB, P = 0.002), and the pattern standard deviation (PSD) (4.6 ± 3.3 versus 2.4 ± 0.9 dB, P = 0.001) were worse for the APAC than the PACS eyes, but both had similar thicknesses of the retinal nerve fiber layer (RNFL) (111.8 ± 9.6 versus 114.1 ± 29.1 μm, P = 0.880) and ganglion cell complex (GCC) (94.7 ± 7.5 versus 91.8 ± 9.3 μm, P = 0.328). The peripapillary retinal vessel density was significantly correlated with the VF MD (vessel density: r = 0.455, P = 0.008) and PSD (vessel density: r = -0.592, P density, which was correlated with the VF values. OCT angiography is a reliable method for detecting vascular changes in glaucomatous eyes that show no thinning of the RNFL and GCC.

  4. Combat ready clamp medic technique.

    Science.gov (United States)

    Tovmassian, Robert V; Kragh, John F; Dubick, Michael A; Baer, David G; Blackbourne, Lorne H

    2012-01-01

    Junctional hemorrhage control device use on the battlefield might be lifesaving, but little experience is reported. The purpose of the present case report is to detail prehospital use of the Combat Ready Clamp (called the CRoC by its users, Combat Medical Systems, Fayetteville, NC; Instructions for Use, 2010) in casualty care in order to increase awareness of junctional hemorrhage control. The CRoC was used to control difficult inguinal bleeding on the battlefield for an Afghani man with a hindquarter traumatic amputation. The device promptly controlled exsanguination from a critical injury when placed during rotary-wing casualty evacuation. The flight medic applied the device in 90 seconds. The device performed well without complications to control bleeding. The CRoC, a new junctional hemorrhage control device, was used as indicated on the battlefield with mechanical and physiologic success and without device problems. By controlling difficult inguinal bleeding resulting from battlefield trauma, the device facilitated casualty stabilization and delivery to a surgical facility. The device facilitated the ability of a new flight medic to focus his expertise on a critically injured battlefield casualty with demonstrable success. 2012.

  5. Retinal and choroidal oxygen saturation of the optic nerve head in open-angle glaucoma subjects by multispectral imaging.

    Science.gov (United States)

    Li, Gai-Yun; Al-Wesabi, Samer Abdo; Zhang, Hong

    2016-12-01

    The aim of this study was to determine whether differences exist in oxygen supply to the optic nerve head (ONH) from the retinal and choroidal vascular layers in patients with primary open angle glaucoma (POAG) using multispectral imaging (MSI).This ia an observational, cross-sectional study.Multispectral images were acquired from 38 eyes of 19 patients with POAG, and 42 healthy eyes from 21 matched volunteers with Annidis' RHA multispectral digital ophthalmoscopy. Superficial and deeper oxygen saturation of the optic disc was represented by the mean gray scale values on the retinal and choroidal oxy-deoxy maps, respectively. Statistical analysis was performed to detect differences in ONH oxygen saturation between the 2 groups. Oxygen saturation levels in the eyes of POAG patients with severe glaucoma were compared to those of fellow eyes from the same subjects. Linear correlation analysis was performed to assess the association between ONH oxygen saturation and systemic and ocular parameters.No statistical difference was found in retinal and choroidal oxygen saturation between the POAG and control groups. In the glaucoma patients, retinal oxygen saturation was lower for eyes with worse visual fields than in those with good visual fields (t = 4.009, P = 0.001). In POAG patients, retinal oxygen saturation was dependent on mean defect of visual field and retinal nerve fiber layer thickness (RNFLT) (r = 0.511, 0.504, P = 0.001, 0.001, respectively), whereas the choroid vasculature oxygen saturation was inversely related to RNFLT (r = -0.391, P = 0.015). An age-dependent increase in retinal oxygen saturation was found for both the POAG and control groups (r = 0.473, 0.410, P = 0.007, 0.003, respectively).MSI revealed a significant correlation between functional and structural impairments in glaucoma and retinal oxygen saturation. MSI could provide objective assessments of perfusion impairments of the glaucomatous ONH. This is a

  6. 3D Cloud Tomography, Followed by Mean Optical and Microphysical Properties, with Multi-Angle/Multi-Pixel Data

    Science.gov (United States)

    Davis, A. B.; von Allmen, P. A.; Marshak, A.; Bal, G.

    2010-12-01

    -type model is used where the cloud surface "emits" either reflected (sunny-side) or transmitted (shady-side) light at different levels. As it turns out, the reflected/transmitted light ratio yields an approximate cloud optical thickness. Another approach is to invoke tomography techniques to define the volume occupied by the cloud using, as it were, cloud masks for each direction of observation. In the shape and opacity refinement phase, initial guesses along with solar and viewing geometry information are used to predict radiance in each pixel using a fast diffusion model for the 3D RT in MISR's non-absorbing red channel (275 m resolution). Refinement is constrained and stopped when optimal resolution is reached. Finally, multi-pixel/mono-angle MODIS data for the same cloud (at comparable 250 m resolution) reveals the desired droplet size information, hence the volume-averaged LWC. This is an ambitious remote sensing science project drawing on cross-disciplinary expertise gained in medical imaging using both X-ray and near-IR sources and detectors. It is high risk but with potentially high returns not only for the cloud modeling community but also aerosol and surface characterization in the presence of broken 3D clouds.

  7. Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-01-01

    Full Text Available Purpose: The aim of the present study was to evaluate the effect of surgical peripheral iridectomy (SPI on choroidal thickness in primary angle-closure suspect (PACS eyes. Materials and Methods: This was a prospective observational case series of 30 subjects with PACS. Ocular biometry was performed before SPI (baseline and then 1 week later. Choroid was imaged by enhanced depth imaging optical coherence tomography (EDI-OCT. The choroidal thickness of the subfoveal area at 1 and 3 mm diameter around the fovea was determined. Central anterior chamber depth (ACD, lens thickness (LT, vitreous chamber depth (VCD, and axial length (AL were measured by A-scan ultrasound. Parameters were compared before SPI (baseline and 1 week later. Results: Thirty eyes of 30 patients with mean age of 61.53 ± 7.98 years were studied. There was no significant difference in the choroidal thickness at all macular locations before and after SPI (all P > 0.05. Mean subfoveal choroidal thickness was 279.61 μm ± 65.50 μm before and 274.54 μm ± 63.36 μm after SPI (P = 0.308. There was also no significant change in central ACD, LT, VCD, and LT after SPI (all P > 0.05. Conclusions: SPI does not appear to alter choroidal thickness in PACS eyes, as assessed using EDI-OCT. Long-term follow-up of PACS eyes treated with SPI may provide further insight into the effects of this treatment modality on the choroid.

  8. Thermo-mechanical analysis of ITER first mirrors and its use for the ITER equatorial visible∕infrared wide angle viewing system optical design.

    Science.gov (United States)

    Joanny, M; Salasca, S; Dapena, M; Cantone, B; Travère, J M; Thellier, C; Fermé, J J; Marot, L; Buravand, O; Perrollaz, G; Zeile, C

    2012-10-01

    ITER first mirrors (FMs), as the first components of most ITER optical diagnostics, will be exposed to high plasma radiation flux and neutron load. To reduce the FMs heating and optical surface deformation induced during ITER operation, the use of relevant materials and cooling system are foreseen. The calculations led on different materials and FMs designs and geometries (100 mm and 200 mm) show that the use of CuCrZr and TZM, and a complex integrated cooling system can limit efficiently the FMs heating and reduce their optical surface deformation under plasma radiation flux and neutron load. These investigations were used to evaluate, for the ITER equatorial port visible∕infrared wide angle viewing system, the impact of the FMs properties change during operation on the instrument main optical performances. The results obtained are presented and discussed.

  9. Fiber optic to integrated optical chip coupler

    Science.gov (United States)

    Pikulski, Joseph I. (Inventor); Ramer, O. Glenn (Inventor)

    1987-01-01

    Optical fibers are clamped by a block onto a substrate. Thereupon, metal is plated over the fibers to hold them in place upon the substrate. The clamp block is removed and the opening, resulting from the clamp block's presence, is then plated in. The built-up metallic body is a coupling which holds the fibers in position so that the ends can be polished for coupling to an integrated optical chip upon a coupling fixture.

  10. Dynamic clamp with StdpC software.

    Science.gov (United States)

    Kemenes, Ildikó; Marra, Vincenzo; Crossley, Michael; Samu, Dávid; Staras, Kevin; Kemenes, György; Nowotny, Thomas

    2011-03-01

    Dynamic clamp is a powerful method that allows the introduction of artificial electrical components into target cells to simulate ionic conductances and synaptic inputs. This method is based on a fast cycle of measuring the membrane potential of a cell, calculating the current of a desired simulated component using an appropriate model and injecting this current into the cell. Here we present a dynamic clamp protocol using free, fully integrated, open-source software (StdpC, for spike timing-dependent plasticity clamp). Use of this protocol does not require specialist hardware, costly commercial software, experience in real-time operating systems or a strong programming background. The software enables the configuration and operation of a wide range of complex and fully automated dynamic clamp experiments through an intuitive and powerful interface with a minimal initial lead time of a few hours. After initial configuration, experimental results can be generated within minutes of establishing cell recording.

  11. Molecular Mechanisms of DNA Polymerase Clamp Loaders

    Science.gov (United States)

    Kelch, Brian; Makino, Debora; Simonetta, Kyle; O'Donnell, Mike; Kuriyan, John

    Clamp loaders are ATP-driven multiprotein machines that couple ATP hydrolysis to the opening and closing of a circular protein ring around DNA. This ring-shaped clamp slides along DNA, and interacts with numerous proteins involved in DNA replication, DNA repair and cell cycle control. Recently determined structures of clamp loader complexes from prokaryotic and eukaryotic DNA polymerases have revealed exciting new details of how these complex AAA+ machines perform this essential clamp loading function. This review serves as background to John Kuriyan's lecture at the 2010 Erice School, and is not meant as a comprehensive review of the contributions of the many scientists who have advanced this field. These lecture notes are derived from recent reviews and research papers from our groups.

  12. Clamp force and alignment checking device

    Energy Technology Data Exchange (ETDEWEB)

    Spicer, John Patrick; Cai, Wayne W.; Chakraborty, Debejyo; Mink, Keith

    2017-04-11

    A check fixture measures a total clamp force applied by a welder device. The welder device includes a welding horn having a plurality of weld pads and welding anvil having a plurality of weld pads. The check fixture includes a base member operatively supporting a plurality of force sensors. The base member and the force sensors are received between the weld pads of the welding horn and the anvil pads of the welding anvil. Each force sensor is configured to measure an individual clamp force applied thereto by corresponding weld and anvil pads when the base member is received between the welding horn and the welding anvil and the welder device is in the clamped position. The individual clamp forces are used to determine whether the weld and/or anvil pads are worn or misaligned.

  13. Analysis of the role of PCNA-DNA contacts during clamp loading

    Directory of Open Access Journals (Sweden)

    Goedken Eric R

    2010-01-01

    Full Text Available Abstract Background Sliding clamps, such as Proliferating Cell Nuclear Antigen (PCNA in eukaryotes, are ring-shaped protein complexes that encircle DNA and enable highly processive DNA replication by serving as docking sites for DNA polymerases. In an ATP-dependent reaction, clamp loader complexes, such as the Replication Factor-C (RFC complex in eukaryotes, open the clamp and load it around primer-template DNA. Results We built a model of RFC bound to PCNA and DNA based on existing crystal structures of clamp loaders. This model suggests that DNA would enter the clamp at an angle during clamp loading, thereby interacting with positively charged residues in the center of PCNA. We show that simultaneous mutation of Lys 20, Lys 77, Arg 80, and Arg 149, which interact with DNA in the RFC-PCNA-DNA model, compromises the ability of yeast PCNA to stimulate the DNA-dependent ATPase activity of RFC when the DNA is long enough to extend through the clamp. Fluorescence anisotropy binding experiments show that the inability of the mutant clamp proteins to stimulate RFC ATPase activity is likely caused by reduction in the affinity of the RFC-PCNA complex for DNA. We obtained several crystal forms of yeast PCNA-DNA complexes, measuring X-ray diffraction data to 3.0 Å resolution for one such complex. The resulting electron density maps show that DNA is bound in a tilted orientation relative to PCNA, but makes different contacts than those implicated in clamp loading. Because of apparent partial disorder in the DNA, we restricted refinement of the DNA to a rigid body model. This result contrasts with previous analysis of a bacterial clamp bound to DNA, where the DNA was well resolved. Conclusion Mutational analysis of PCNA suggests that positively charged residues in the center of the clamp create a binding surface that makes contact with DNA. Disruption of this positive surface, which had not previously been implicated in clamp loading function, reduces RFC

  14. Comparative study of the retinal nerve fibre layer thickness performed with optical coherence tomography and GDx scanning laser polarimetry in patients with primary open-angle glaucoma.

    Science.gov (United States)

    Wasyluk, Jaromir T; Jankowska-Lech, Irmina; Terelak-Borys, Barbara; Grabska-Liberek, Iwona

    2012-03-01

    We compared the parameters of retinal nerve fibre layer in patients with advanced glaucoma with the use of different OCT (Optical Coherence Tomograph) devices in relation to analogical measurements performed with GDx VCC (Nerve Fiber Analyzer with Variable Corneal Compensation) scanning laser polarimetry. Study subjects had advanced primary open-angle glaucoma, previously treated conservatively, diagnosed and confirmed by additional examinations (visual field, ophthalmoscopy of optic nerve, gonioscopy), A total of 10 patients were enrolled (9 women and 1 man), aged 18-70 years of age. Nineteen eyes with advanced glaucomatous neuropathy were examined. 1) Performing a threshold perimetry Octopus, G2 strategy and ophthalmoscopy of optic nerve to confirm the presence of advanced primary open-angle glaucoma; 2) performing a GDx VCC scanning laser polarimetry of retinal nerve fibre layer; 3) measuring the retinal nerve fibre layer thickness with 3 different optical coherence tomographs. The parameters of the retinal nerve fibre layer thickness are highly correlated between the GDx and OCT Stratus and 3D OCT-1000 devices in mean retinal nerve fibre layer thickness, retinal nerve fibre layer thickness in the upper sector, and correlation of NFI (GDx) with mean retinal nerve fibre layer thickness in OCT examinations. Absolute values of the retinal nerve fibre layer thickness (measured in µm) differ significantly between GDx and all OCT devices. Examination with OCT devices is a sensitive diagnostic method of glaucoma, with good correlation with the results of GDx scanning laser polarimetry of the patients.

  15. Ergonomic redesign and evaluation of a clamping tool handle.

    Science.gov (United States)

    Jung, Myung-Chul; Hallbeck, M Susan

    2005-09-01

    The handle of a commercial bar clamp was redesigned using ergonomic principles and then compared with an original clamp. Ten male and ten female students participated in simulated clamping tasks under various conditions, including different clamping heights, clamping methods, and handle-gripping methods, with respect to the dependent variables of clamping and handle-squeezing forces. The results showed that the redesigned clamp produced larger clamping force with lower handle-squeezing forces than the original clamp. As expected, males exerted more force than females in both clamping and squeezing forces. A pistol grip method was superior to an upside-down handle-gripping method. Two-handed operation was recommended for this type of clamp by simultaneously pulling the trigger and sliding the bar in order to initially tighten around objects. This study shows that the application of ergonomic guidelines increases the efficiency and usability of manual handtools.

  16. Preparation and Angle-Dependent Optical Properties of Brown Al/MnO2 Composite Pigments in Visible and Infrared Region

    Science.gov (United States)

    Liu, Yunfeng; Xie, Jianliang; Luo, Mei; Peng, Bo; Deng, Longjiang

    2017-04-01

    Traditional low infrared emissivity coatings based on aluminum flakes cannot own low IR emissivity and low lightness simultaneously. Herein, a new simple efficient method for the synthesis of brown Al/MnO2 composite pigments with low IR emissivity and low lightness is reported, through forming MnO2 layer on aluminum flakes by thermal cracking, then altering the shape and forming nanoshell by stirring in hot flowing liquid. The results indicate that the MnO2 particles, which have tetragonal structure with high crystallinity, are needlelike and forming a complete shell on the aluminum flakes. The optical properties of composite pigments can be tuned by mass of KMnO4 added in precursor and time of hot flowing. Strong angle-dependent optical effects are observed in five different angles through multi-angle reflectance spectrum, while low lightness and low IR emissivity are preserved. This work is expected to provide a new route for the preparation of colored aluminum effect pigments in low infrared emissivity coatings.

  17. Piezoresistive cantilever force-clamp system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Goodman, Miriam B. [Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305 (United States)

    2011-04-15

    We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of {mu}N force and nm up to tens of {mu}m displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

  18. Arterial clamping leads to stenosis at clamp sites after femoropopliteal bypass surgery

    NARCIS (Netherlands)

    Vriens, Bianca H. R.; Pol, Robert A.; Hulsebos, Robin G.; van Det, Rob J.; van der Palen, Job; Zeebregts, Clark J.; Geelkerken, Robert H.

    2015-01-01

    BACKGROUND: To date, the incidence and clinical relevance of arterial stenosis at clamp sites after femoropopliteal bypass surgery is unknown. METHODS: Ninety-four patients underwent a femoropopliteal bypass in which the arterial inflow and outflow clamp sites were controlled by the Fogarty-Soft-Inl

  19. Arterial clamping leads to stenosis at clamp sites after femoropopliteal bypass surgery

    NARCIS (Netherlands)

    Vriens, Bianca H.R.; Pol, Robert A.; Hulsebos, Robin G.; Det, van Rob J.; Palen, van der Job; Zeebregts, Clark J.; Geelkerken, Robert H.

    2015-01-01

    Background To date, the incidence and clinical relevance of arterial stenosis at clamp sites after femoropopliteal bypass surgery is unknown. Methods Ninety-four patients underwent a femoropopliteal bypass in which the arterial inflow and outflow clamp sites were controlled by the Fogarty-Soft-Inla

  20. Vascular clamping in liver surgery: physiology, indications and techniques

    Directory of Open Access Journals (Sweden)

    Cherqui Daniel

    2010-03-01

    Full Text Available Abstract This article reviews the historical evolution of hepatic vascular clamping and their indications. The anatomic basis for partial and complete vascular clamping will be discussed, as will the rationales of continuous and intermittent vascular clamping. Specific techniques discussed and described include inflow clamping (Pringle maneuver, extra-hepatic selective clamping and intraglissonian clamping and outflow clamping (total vascular exclusion, hepatic vascular exclusion with preservation of caval flow. The fundamental role of a low Central Venous Pressure during open and laparoscopic hepatectomy is described, as is the difference in their intra-operative measurements. The biological basis for ischemic preconditioning will be elucidated. Although the potential dangers of vascular clamping and the development of modern coagulation devices question the need for systemic clamping; the pre-operative factors and unforseen intra-operative events that mandate the use of hepatic vascular clamping will be highlighted.

  1. Compact, Stiff, Remotely-Actuable Quick-Release Clamp

    Science.gov (United States)

    Tsai, Ted W. (Inventor)

    2000-01-01

    The present invention provides a clamp that is compact and lightweight, yet provides high holding strength and stiffness or rigidity. The clamp uses a unique double slant interface design which provides mechanical advantages to resist forces applied to the clamp member as the load increases. The clamp allows for rapid and remote-activated release of the clamp jaws by applying only a small operating force to an over-center lock/release mechanism, such as by pulling a manual tether.

  2. IMPORTANT: Fluke is recalling Digital Clamp Meters

    CERN Multimedia

    2013-01-01

    Fluke is voluntarily recalling four models of Digital Clamp Meters: Fluke 373, 374, 375 and 376. If you own one of these clamp meters, please stop using it and send it back to Fluke for repair even if you have not experienced problems.   Description of the problem: "The printed circuit assembly may not be properly fastened to the test lead input jack. This may result in inaccurate voltage readings, including a low or no-voltage reading on a circuit energised with a hazardous voltage, presenting a shock, electrocution or thermal burn hazard." To determine if your clamp meter is affected by this recall notice, and for more information, click here.

  3. Design and application of multifunctional stomach clamp

    Institute of Scientific and Technical Information of China (English)

    Yun Fu Lu; Pi Wu Li; Xir Xin Zhang

    2000-01-01

    AIM Pylorus and pyloric vagus preserving gastrectomy (PPVPG) is an efficient operation mode for treatinggastric and duodenal ulcers. For its better application and popularization, we have designed andmanufactured a special multifunctional stomach clamp.METHODS The clamp has been designed carefully in view of the different sizes of the patients' stomachsand the different starting points of Latarjer nerves so as to facilitate the execution of the present operationmode, which requires the preservation of the vagus innervated pyloric region so as to make the remnantstomach maintain its normal physiological function and the vagus branches clinging antral seromuscular flapkept in proper size so that avoiding too much remaining antral mucosa is removed to cause greater difficultyin operation. With this in view, we observed and measured the distance between the Latarjer nerves distribution and the pyloric rings of 42 patients' stomachs in the course of operations. We bent an aluminumstring 3 mm thick for each stomach according to the size of antral seromuecular flap and chose an optimalcurvature from the 42 sizes for manufacturing the clamp. The clamp is made of 3 Cr13 stainless steel,consisting of three parts, the curved head, the fastening ring and the handle. The curved head is shapedalmost exactly like the remained antral seromuscular flap. The ring at its tip when in place fastens the twosides of the clamp so that the tissue of the stomach between will be clutched by an even force. On one sideare three cuts for moving the ring upwards, each cut representing 1 mm for fastening and adjustments can bemade in view of the thickness or thinness of the tissue. The handles bend backward for fighting shy of thecuts so as to facilitate the operation.RESULTS With the stomach disassociated in the light of PPVPG procedures, the clamp may easily beapplied from the upper part of the Latarjer nerves. The following merits can be noted. ① The curving line ofthe flap can be precisely

  4. 宽视角光学接收天线研究与进展%The Research and Progress on Optical Receiving Antenna of Wide Viewing Angle

    Institute of Scientific and Technical Information of China (English)

    孙文昌; 袁丹

    2012-01-01

      The viewing angle division is generally used in optical receiving antenna of wide viewing angle, using more detectors or complex access system (such as fiber array), but it is mainly used for the orientation detection in optoelectronic countermeasures, not suitable for laser communication. Based on the field of space laser telecommunication and research progress on the optical antenna of wide viewing angle, the existing technology has been compared and analyzed. Considering the viewing angle, optical gain and aberration, this paper has put forward a new idea about this new system and set up a good foundation for the further research, focusing on the index demand of wide viewing angle and large aperture receiving area, which is based on the antenna array and a small receiving area for photoelectric detector to simple the structure and reduce the cost.%  目前的宽视角的接收一般采用视角分割,以使用多探测器或者复杂接收系统(如光纤阵列)等方式获得,但以上方式主要用于光电对抗的方位探测,在空间激光通信等场合难以适用。基于空间激光通信领域,结合目前宽视角光学接收天线的研究和进展情况,比较分析了现有的技术后,综合考虑视角、光学增益及像差大小,提出一种系统的新思路,针对宽视角、大口径接收面积的指标需求,以小接收面积光电探测器、阵列化天线为约束前提,力争结构简单、经济合理,为后续的深入研究打下良好的基础。

  5. Grazing-angle fiber-optic fourier transform infrared reflection-absorption spectroscopy for the in situ detection and quantification of two active pharmaceutical ingredients on glass.

    Science.gov (United States)

    Perston, Benjamin B; Hamilton, Michelle L; Williamson, Bryce E; Harland, Peter W; Thomson, Mary A; Melling, Peter J

    2007-02-01

    Fourier transform infrared reflection-absorption spectroscopy has been used with a fiber-optic grazing-angle reflectance probe as a rapid, in situ method for trace surface analysis of acetaminophen and aspirin at loadings of approximately 0-2 microg cm(-2) on glass. Partial least-squares multivariate regression permits the loadings to be quantified, simultaneously, with root-mean-squared errors of prediction of RMSEP approximately 0.1 microg cm(-2) for both compounds. The detection limits are estimated to be LD approximately 0.2 microg cm(-2).

  6. Two-Dimensional Fiber Positioning and Clamping Device for Product-Internal Microassembly

    NARCIS (Netherlands)

    Henneken, V.A.; Sassen, W.P.; Van der Vlist, W.; Wien, W.H.A.; Tichem, M.; Sarro, P.M.

    2008-01-01

    In this paper, we present a microelectromechanical systems-based two-degrees-of-freedom positioning device combined with a clamping structure for positioning and constraining an optical fiber. The fiber position can be controlled in the two directions perpendicular to the fiber axis using two specif

  7. Two-Dimensional Fiber Positioning and Clamping Device for Product-Internal Microassembly

    NARCIS (Netherlands)

    Henneken, V.A.; Sassen, W.P.; Van der Vlist, W.; Wien, W.H.A.; Tichem, M.; Sarro, P.M.

    2008-01-01

    In this paper, we present a microelectromechanical systems-based two-degrees-of-freedom positioning device combined with a clamping structure for positioning and constraining an optical fiber. The fiber position can be controlled in the two directions perpendicular to the fiber axis using two specif

  8. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics.

    Science.gov (United States)

    Springelkamp, Henriët; Iglesias, Adriana I; Mishra, Aniket; Höhn, René; Wojciechowski, Robert; Khawaja, Anthony P; Nag, Abhishek; Wang, Ya Xing; Wang, Jie Jin; Cuellar-Partida, Gabriel; Gibson, Jane; Bailey, Jessica N Cooke; Vithana, Eranga N; Gharahkhani, Puya; Boutin, Thibaud; Ramdas, Wishal D; Zeller, Tanja; Luben, Robert N; Yonova-Doing, Ekaterina; Viswanathan, Ananth C; Yazar, Seyhan; Cree, Angela J; Haines, Jonathan L; Koh, Jia Yu; Souzeau, Emmanuelle; Wilson, James F; Amin, Najaf; Müller, Christian; Venturini, Cristina; Kearns, Lisa S; Kang, Jae Hee; Tham, Yih Chung; Zhou, Tiger; van Leeuwen, Elisabeth M; Nickels, Stefan; Sanfilippo, Paul; Liao, Jiemin; van der Linde, Herma; Zhao, Wanting; van Koolwijk, Leonieke M E; Zheng, Li; Rivadeneira, Fernando; Baskaran, Mani; van der Lee, Sven J; Perera, Shamira; de Jong, Paulus T V M; Oostra, Ben A; Uitterlinden, André G; Fan, Qiao; Hofman, Albert; Tai, E-Shyong; Vingerling, Johannes R; Sim, Xueling; Wolfs, Roger C W; Teo, Yik Ying; Lemij, Hans G; Khor, Chiea Chuen; Willemsen, Rob; Lackner, Karl J; Aung, Tin; Jansonius, Nomdo M; Montgomery, Grant; Wild, Philipp S; Young, Terri L; Burdon, Kathryn P; Hysi, Pirro G; Pasquale, Louis R; Wong, Tien Yin; Klaver, Caroline C W; Hewitt, Alex W; Jonas, Jost B; Mitchell, Paul; Lotery, Andrew J; Foster, Paul J; Vitart, Veronique; Pfeiffer, Norbert; Craig, Jamie E; Mackey, David A; Hammond, Christopher J; Wiggs, Janey L; Cheng, Ching-Yu; van Duijn, Cornelia M; MacGregor, Stuart

    2017-01-15

    Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increased risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genome-wide association meta-analysis of IOP and optic disc parameters and validated our findings in multiple sets of POAG cases and controls. Using imputation to the 1000 genomes (1000G) reference set, we identified 9 new genomic regions associated with vertical cup-disc ratio (VCDR) and 1 new region associated with IOP. Additionally, we found 5 novel loci for optic nerve cup area and 6 for disc area. Previously it was assumed that genetic variation influenced POAG either through IOP or via changes to the optic nerve head; here we present evidence that some genomic regions affect both IOP and the disc parameters. We characterized the effect of the novel loci through pathway analysis and found that pathways involved are not entirely distinct as assumed so far. Further, we identified a novel association between CDKN1A and POAG. Using a zebrafish model we show that six6b (associated with POAG and optic nerve head variation) alters the expression of cdkn1a. In summary, we have identified several novel genes influencing the major clinical risk predictors of POAG and showed that genetic variation in CDKN1A is important in POAG risk. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Prolonged penile strangulation with metal clamps

    Institute of Scientific and Technical Information of China (English)

    Chirag Patel; Richard Kim; Michael Delterzo; Run Wang

    2006-01-01

    Various different objects have been reported to strangulate the penis. We reported on a patient who used metal radiator clamps for an extended period of time. Workup included history, physical examination and urinalysis. The patient was taken to the operating room for further evaluation with cystourethroscopy and orthopedic wire cutters were used to break the metal bands.

  10. On the importance of vibrational contributions to small-angle optical rotation: Fluoro-oxirane in gas phase and solution

    Science.gov (United States)

    Pedersen, Thomas Bondo; Kongsted, Jacob; Crawford, T. Daniel; Ruud, Kenneth

    2009-01-01

    The specific optical rotation of (S)-fluoro-oxirane in gas phase and solution is predicted using time-dependent density functional theory (B3LYP functional) and coupled cluster linear response theory. Upon vibrational averaging, the coupled cluster singles and doubles model predicts the gas phase specific optical rotation to be 8.1° (dm g/cm3)-1 at 355 nm at room temperature. This is an order of magnitude smaller than the B3LYP result of 68.4° (dm g/cm3)-1. The main source of this discrepancy is the electronic contribution at the equilibrium geometry. The effects of cyclohexane and acetonitrile solvents are calculated for both the electronic and vibrational contributions with the B3LYP functional. The specific optical rotation is estimated to change significantly depending on the polarity of the solvent, increasing in cyclohexane and decreasing in acetonitrile.

  11. Measurement of the infrared optical constants for spectral modeling: n and k values for (NH4)2SO4 via single-angle reflectance and ellipsometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Blake, Thomas A.; Brauer, Carolyn S.; Kelly-Gorham, Molly Rose K.; Burton, Sarah D.; Bliss, Mary; Myers, Tanya L.; Johnson, Timothy J.; Tiwald, Thomas E.

    2017-05-05

    The optical constants n and k can be used to model infrared spectra, including refraction, absorption, reflectance, and emissivity, but obtaining reliable values for solid materials (pure or otherwise) presents a challenge: In the past, the best results for n and k have been obtained from bulk, homogeneous materials, free of defects. That is, materials where the Fresnel equations are operant since there is no light scattering. Since it is often not possible to obtain a pure macroscopic (crystalline) material, it may be possible to press the material into a (uniform, void-free) disk. We have recently been able to do this with ammonium sulfate powder and then measured the n & k values via two independent methods: 1) Ellipsometry - which measures the changes in amplitude and phase of light reflected from the material of interest as a function of wavelength and angle of incidence, and 2) Single angle specular reflectance with an FT spectrometer using a specular reflectance device within an FT instrument which measures the change in amplitude of light reflected from the material of interest as a function of wavelength and angle of incidence over a wide wavelength range. The quality of the derived n & k values was tested by generating the reflectance spectra of the pellet and comparing to the calculated to measured reflectance spectra of the pure material which has been previously published. The comparison to literature values showed good accuracy and good agreement, indicating promise to measure other materials by such methods.

  12. Cerebral haemodynamics during carotid cross-clamping.

    Science.gov (United States)

    Pistolese, G R; Ippoliti, A; Appolloni, A; Ronchey, S; Faraglia, V

    1993-03-01

    Carotid artery cross-clamping ischaemia during carotid endarterectomy (CEA) causes 5-30% of perioperative neurological deficits. This study was performed to identify possible clinical situations at higher risk for carotid cross-clamping ischaemia. 606 consecutive patients underwent CEA and were retrospectively studied; they were grouped according to risk factors, presence of associated vascular diseases, clinical pattern, angiographic and CT scan findings. Stump pressure measurement was provided in all patients, perioperative monitoring during CEA was performed by electroencephalogram (EEG) in 469 (77%) and somatosensorial evoked potentials (SEP) in 137 (23%). Local anaesthesia was used in 88 (14.5%) patients. Ischaemic changes during carotid cross-clamping were registered in 118 patients (19.5%). The incidence of cross-clamping ischaemia was then related to different factors; it affected 5.6% of asymptomatics, 25.4% of patients with fixed stroke and 38.5% of those with stenosis and contralateral occlusion. Angiographic and clinical correlation showed that patients with more severe lesions are mostly affected by clamping ischaemia (up to 55% in those with stroke and stenosis with contralateral occlusion). Age, hypertension and diabetes do not significantly affect incidence of ischaemic changes. Positive CT scan increased this risk; statistical relevance was found in regard to patients with unilateral or bilateral stenosis and in those with transient ischaemic attacks. A higher risk can be expected for subjects with more severe clinical and instrumental findings, even if no patients can be considered completely at risk or risk free. Perioperative monitoring is always mandatory and is of great importance in detecting ischaemic changes and preventing cerebral damage using a temporary intraluminal shunt.

  13. NONLINEAR-OPTICAL PROPERTIES OF AZO-DYE MONOLAYERS - THE EFFECT OF TILT ANGLE ON THE LOCAL-FIELD

    NARCIS (Netherlands)

    CNOSSEN, G; DRABE, KE; WIERSMA, DA; SCHOONDORP, MA; SCHOUTEN, AJ; HULSHOF, JBE; FERINGA, BL

    1993-01-01

    We report on the second-order nonlinear optical susceptibility chi(2)(2omega,omega,omega) of dye-doped Langmuir-Blodgett monolayers. Chi(2) is found to exhibit a nonlinear dependence on surface density, which is attributed to microscopic local-fields. In order to calculate the microscopic local-fiel

  14. Nuclear Technology. Course 27: Metrology. Module 27-4, Angle Measurement Instruments, Optical Projections and Surface Texture Gages.

    Science.gov (United States)

    Selleck, Ben; Espy, John

    This fourth in a series of eight modules for a course titled Metrology describes the universal bevel protractor and the sine bar, the engineering microscope and optical projector, and several types of surface texture gages. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3)…

  15. Dynamics and Stability of Pinned-Clamped and Clamped-Pinned Cylindrical Shells Conveying Fluid

    Science.gov (United States)

    Misra, A. K.; Wong, S. S. T.; Païdoussis, M. P.

    2001-11-01

    The paper examines the dynamics and stability of fluid-conveying cylindrical shells having pinned-clamped or clamped-pinned boundary conditions, where ``pinned'' is an abbreviation for ``simply supported''. Flügge's equations are used to describe the shell motion, while the fluid-dynamic perturbation pressure is obtained utilizing the linearized potential flow theory. The solution is obtained using two methods - the travelling wave method and the Fourier-transform approach. The results obtained by both methods suggest that the negative damping of the clamped-pinned systems and positive damping of the pinned-clamped systems, observed by previous investigators for any arbitrarily small flow velocity, are simply numerical artefacts; this is reinforced by energy considerations, in which the work done by the fluid on the shell is shown to be zero. Hence, it is concluded that both systems are conservative.

  16. Imperfect space clamp permits electrotonic interactions between inhibitory and excitatory synaptic conductances, distorting voltage clamp recordings.

    Directory of Open Access Journals (Sweden)

    Alon Poleg-Polsky

    Full Text Available The voltage clamp technique is frequently used to examine the strength and composition of synaptic input to neurons. Even accounting for imperfect voltage control of the entire cell membrane ("space clamp", it is often assumed that currents measured at the soma are a proportional indicator of the postsynaptic conductance. Here, using NEURON simulation software to model somatic recordings from morphologically realistic neurons, we show that excitatory conductances recorded in voltage clamp mode are distorted significantly by neighboring inhibitory conductances, even when the postsynaptic membrane potential starts at the reversal potential of the inhibitory conductance. Analogous effects are observed when inhibitory postsynaptic currents are recorded at the reversal potential of the excitatory conductance. Escape potentials in poorly clamped dendrites reduce the amplitude of excitatory or inhibitory postsynaptic currents recorded at the reversal potential of the other conductance. In addition, unclamped postsynaptic inhibitory conductances linearize the recorded current-voltage relationship of excitatory inputs comprising AMPAR and NMDAR-mediated components, leading to significant underestimation of the relative contribution by NMDARs, which are particularly sensitive to small perturbations in membrane potential. Voltage clamp accuracy varies substantially between neurons and dendritic arbors of different morphology; as expected, more reliable recordings are obtained from dendrites near the soma, but up to 80% of the synaptic signal on thin, distant dendrites may be lost when postsynaptic interactions are present. These limitations of the voltage clamp technique may explain how postsynaptic effects on synaptic transmission could, in some cases, be attributed incorrectly to presynaptic mechanisms.

  17. Towards a Dynamic Clamp for Neurochemical Modalities

    Directory of Open Access Journals (Sweden)

    Catalina Maria Rivera

    2015-05-01

    Full Text Available The classic dynamic clamp technique uses a real-time electrical interface between living cells and neural simulations in order to investigate hypotheses about neural function and structure. One of the acknowledged drawbacks of that technique is the limited control of the cells’ chemical microenvironment. In this manuscript, we use a novel combination of nanosensor and microfluidic technology and microfluidic and neural simulations to add sensing and control of chemical concentrations to the dynamic clamp technique. Specifically, we use a microfluidic lab-on-a-chip to generate distinct chemical concentration gradients (ions or neuromodulators, to register the concentrations with embedded nanosensors and use the processed signals as an input to simulations of a neural cell. The ultimate goal of this project is to close the loop and provide sensor signals to the microfluidic lab-on-a-chip to mimic the interaction of the simulated cell with other cells in its chemical environment.

  18. Mechanical and metallurgical properties of carotid artery clamps.

    Science.gov (United States)

    Dujovny, M; Kossovsky, N; Kossowsky, R; Segal, R; Diaz, F G; Kaufman, H; Perlin, A; Cook, E E

    1985-11-01

    The mechanical and metallurgical properties of carotid artery clamps were evaluated. The pressure plate retreat propensity, metallurgical composition, surface morphology, magnetic properties, and corrosion resistance of the Crutchfield, Selverstone, Salibi, and Kindt clamps were tested. None of the clamps showed evidence of pressure plate retreat. The clamps differed significantly in their composition, surface cleanliness, magnetic properties, and corrosion resistance. The Crutchfield clamp was the only one manufactured from an ASTM-ANSI-approved implantable stainless steel (AISI 316) and the only clamp in which the surfaces were clean and free of debris. The Selverstone clamp was made principally from AISI 304 stainless steel, as was one Salibi clamp. The pressure plate on another Salibi clamp was made from a 1% chromium and 1% manganese steel. Machining and surface debris consisting principally of aluminum, silicon, and sulfur was abundant on the Selverstone and Salibi clamps. The Kindt clamp was manufactured from AISI 301 stainless steel with a silicate-aluminized outer coating. The Crutchfield and Selverstone clamps were essentially nonferromagnetic, whereas the Salibi and Kindt clamps were sensitive to magnetic flux. In the pitting potential corrosion test, the Crutchfield clamp demonstrated good corrosion resistance with a pitting potential of 310 mV and no surface corrosion or pitting by scanning electron microscopy examination. The Selverstone clamp had lower pitting potentials and showed various degrees of corrosion and surface pitting by scanning electron microscopy. The Salibi pressure plate had a very low pitting potential of -525 mV and showed severe corrosion. By metallurgical criteria, only the Crutchfield clamp is suitable for long term implantation.

  19. Γ-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....

  20. AN ACTIVE VALVE WITH A CLAMPED MEMBRANE

    DEFF Research Database (Denmark)

    2009-01-01

    An active valve for use e.g. in fluidic microsystems is provided, wherein the active valve comprises a membrane having at least one flow gate, arranged between a first and a second substantially rigid element. Adjusting means provides an adjustment of the clamping force on membrane arranged between...... the first and second substantially rigid element. Hereby the flow rate through the active valve can be continuously and precisely controlled....

  1. Vibration of an eccentrically clamped annular plate

    Science.gov (United States)

    Tseng, J.-G.; Wickert, J. A.

    1994-04-01

    Small amplitude vibration of an eccentric annular plate, which is free along its outer edge and clamped along the interior, is investigated through experimental and analytical methods. A disk with this geometry, or a stacked array in which the clamping and symmetry axes of each disk are nominally coincident, is common in data storage and brake systems applications. In the present case, the geometric imperfections on the boundary can have important implications for the disk's dynamic response. Changes that occur in the natural frequency spectrum, the mode shapes, and the free response under eccentric mounting are studied through laboratory measurements and an approximate discrete model of the plate. The natural frequencies and modes are found through global discretization of the Kamke quotient for a classical thin plate. For the axisymmetric geometry, the natural frequencies of the sine and cosine vibration modes for a specified number of nodal diameters are repeated. With increasing eccentricity, on the other hand, each pair of repeated frequencies splits at a rate that depends on the number of nodal diameters. Over a range of clamping and eccentricity ratios, the model's predictions are compared to the measured results.

  2. Multilevel-clamped multilevel converters (MLC2)

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Bellar, Maria Dias; Muñoz-Aguliar, Raúl Santiago;

    2012-01-01

    This letter introduces a new series of multilevel (ML) converters based on the ML clamping concept. By applying this technique, a ML clamping unit (MCU) conveys additional levels for synthesizing the output waveforms of a diode-clampedML dc– ac power converter. The basic building block of the ML ...

  3. Analysis of the Pallet Clamping Conditions in Work Positioning

    Directory of Open Access Journals (Sweden)

    L. A. Kolesnikov

    2016-01-01

    Full Text Available Pallets of automatic transfer lines serve as the technological and work-transfer equipment. However, their design is based on the general principles of designing machine accessories. Calculation of the basic design parameters of work based on their functioning features is fairly relevant.In pallet transfer movement over work positioning there is a mismatch between axes of the basic bushing of a pallet and the clamping locks of positioning. The paper identifies the factors influencing it, and defines the conditions to ensure the trouble-free clamping lock. The circular and rhombic clamping of pallet is simultaneous. Further, a clamping load is calculated from the pallet mass (together with the work-piece and the geometric parameters of the pallet clamping.The paper reveals three movement stages of the clamping lock in a vertical plane when setting the pallet in work positioning:- a clamping lock free play till it encounters with the location bushing;- a clamping lock play length when the lead-in chamfer contacts the bushing chamfer;- a clamping lock play length over the circular surface of bushing.The study of this process has allowed us to calculate the time of pallet clamping and dynamic loads acting on the clamping lock. These calculations made it possible to calculate the required diameter of the clamping lock. The presented calculations allow a reasonable assigning the main design parameters of work positioning for the pallet automatic lines.

  4. Single molecule study of a processivity clamp sliding on DNA

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, T A; Kwon, Y; Johnson, A; Hollars, C; O?Donnell, M; Camarero, J A; Barsky, D

    2007-07-05

    Using solution based single molecule spectroscopy, we study the motion of the polIII {beta}-subunit DNA sliding clamp ('{beta}-clamp') on DNA. Present in all cellular (and some viral) forms of life, DNA sliding clamps attach to polymerases and allow rapid, processive replication of DNA. In the absence of other proteins, the DNA sliding clamps are thought to 'freely slide' along the DNA; however, the abundance of positively charged residues along the inner surface may create favorable electrostatic contact with the highly negatively charged DNA. We have performed single-molecule measurements on a fluorescently labeled {beta}-clamp loaded onto freely diffusing plasmids annealed with fluorescently labeled primers of up to 90 bases. We find that the diffusion constant for 1D diffusion of the {beta}-clamp on DNA satisfies D {le} 10{sup -14} cm{sup 2}/s, much slower than the frictionless limit of D = 10{sup -10} cm{sup 2}/s. We find that the {beta} clamp remains at the 3-foot end in the presence of E. coli single-stranded binding protein (SSB), which would allow for a sliding clamp to wait for binding of the DNA polymerase. Replacement of SSB with Human RP-A eliminates this interaction; free movement of sliding clamp and poor binding of clamp loader to the junction allows sliding clamp to accumulate on DNA. This result implies that the clamp not only acts as a tether, but also a placeholder.

  5. 21 CFR 882.4460 - Neurosurgical head holder (skull clamp).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neurosurgical head holder (skull clamp). 882.4460 Section 882.4460 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... holder (skull clamp). (a) Identification. A neurosurgical head holder (skull clamp) is a device used...

  6. External mean flow influence on sound transmission through finite clamped double-wall sandwich panels

    Science.gov (United States)

    Liu, Yu; Catalan, Jean-Cédric

    2017-09-01

    This paper studies the influence of an external mean flow on the sound transmission through finite clamped double-wall sandwich panels lined with poroelastic materials. Biot's theory is employed to describe wave propagation in poroelastic materials and various configurations of coupling the poroelastic layer to the facing plates are considered. The clamped boundary of finite panels are dealt with by the modal superposition theory and the weighted residual (Garlekin) method, leading to a matrix equation solution for the sound transmission loss (STL) through the structure. The theoretical model is validated against existing theories of infinite sandwich panels with and without an external flow. The numerical results of a single incident wave show that the external mean flow has significant effects on the STL which are coupled with the clamped boundary effect dominating in the low-frequency range. The external mean flow also influences considerably the limiting incidence angle of the panel system and the effect of the incidence angle on the STL. However, the influences of the azimuthal angle and the external flow orientation are negligible.

  7. Dynamic and static control of the optical phase of guided p-polarized light for near-field focusing at large angles of incidence

    Science.gov (United States)

    Huang, Danhong; Michelle Easter, M.; David Wellems, L.; Mozer, Henry; Gumbs, Godfrey; Cardimona, D. A.; Maradudin, A. A.

    2013-07-01

    Both dynamic and static approaches are proposed and investigated for controlling the optical phase of a p-polarized light wave guided through a surface-patterned metallic structure with subwavelength features. For dynamic control, the important role of photo-excited electrons in a slit-embedded atomic system with field-induced transparency (FIT) is discovered within a narrow frequency window for modulating the intensity of focused transmitted light in the near-field region. This is facilitated by electromagnetic coupling to surface plasmons between the two FIT-atom embedded slits. The near-field distribution can be adjusted by employing a symmetric (or asymmetric) slit configuration and by a small (or large) slit separation. In addition, the cross-transmission of a light beam is also predicted as a result of this strong coupling between optical transitions in embedded FIT atoms and surface plasmons. For static control, the role of surface curvature is found for focused transmitted light passing through a Gaussian-shaped metallic microlens embedded with a linear array of slits. A negative light-refraction pattern, which is associated with higher-order diffraction modes, was also found for large angles of incidence in the near-field region. This anomalous negative refraction can be suppressed when higher-order waveguide modes of light leak through a very thin film. In addition, this negative refraction can also be suppressed with a reinforced reflection at the left foothill of a Gaussian-shaped slit array of the forward-propagating surface-plasmon wave at large angles of incidence. A prediction is given of near-field focusing of light with its sharpness dynamically controlled by the frequency of the light in a very narrow window. Moreover, a different scheme based on Green's second integral identity is proposed for overcoming a difficulty in calculating the near-field distribution very close to a metallic surface by means of a finite-difference-time-domain method.

  8. Novel Melt-Spun Polymer-Optical Poly(methyl methacrylate Fibers Studied by Small-Angle X-ray Scattering

    Directory of Open Access Journals (Sweden)

    Markus Beckers

    2017-02-01

    Full Text Available The structural properties of novel melt-spun polymer optical fibers (POFs are investigated by small-angle X-ray scattering. The amorphous PMMA POFs were subjected to a rapid cooling in a water quench right after extrusion in order to obtain a radial refractive index profile. Four fiber samples were investigated with small-angle X-ray scattering (SAXS. The resulting distance-distribution functions obtained from the respective equatorial and meridional SAXS data exhibit a real-space correlation peak indicative of periodic cross-sectional and axial variations in the scattering density contrast. Simple model calculations demonstrate how the structural information contained particularly in the equatorial distance distribution function can be interpreted. The respective results are qualitatively verified for one of the fiber samples by comparison of the model curve with the measured SAXS data. Eventually, the study confirms that the cross-sectional variation of the (scattering- density is the main reason for the formation of radial refractive-index profiles in the POFs.

  9. Role of apoptosis in the рathogenesis of glaucomatous optic nerve damage during primary open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    M. A. Frolov

    2014-07-01

    Full Text Available This work is devoted to the study of the molecular mechanisms of programmed cell death or apoptosis in primary open-angleglaucoma. As one of the main factors in the pathogenesis of this disease appears the loss of retinal ganglion cells. Their death occursby apoptosis — programmed suicide mechanism. We consider two major apoptotic pathways, which are described in the literature —Fas-mediated and Bcl-2-dependent or mitochondrial. The existence of these paths and their regulators in many organs and tissues isdescribed, including the retina and optic nerve. Based on the analysis of domestic and foreign literature is presented modern view ofthe stages of this process in glaucoma. A thorough understanding of the mechanisms of apoptosis and their regulation may contribute to the development of new pharmacological methods of prevention and treatment of eye diseases

  10. Role of apoptosis in the рathogenesis of glaucomatous optic nerve damage during primary open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    M. A. Frolov

    2013-01-01

    Full Text Available This work is devoted to the study of the molecular mechanisms of programmed cell death or apoptosis in primary open-angleglaucoma. As one of the main factors in the pathogenesis of this disease appears the loss of retinal ganglion cells. Their death occursby apoptosis — programmed suicide mechanism. We consider two major apoptotic pathways, which are described in the literature —Fas-mediated and Bcl-2-dependent or mitochondrial. The existence of these paths and their regulators in many organs and tissues isdescribed, including the retina and optic nerve. Based on the analysis of domestic and foreign literature is presented modern view ofthe stages of this process in glaucoma. A thorough understanding of the mechanisms of apoptosis and their regulation may contribute to the development of new pharmacological methods of prevention and treatment of eye diseases

  11. Measurement of the infrared optical constants for spectral modeling: n and k values for (NH4)2SO4 via single-angle reflectance and ellipsometric methods

    Science.gov (United States)

    Blake, Thomas A.; Brauer, Carolyn S.; Kelly-Gorham, Molly Rose; Burton, Sarah D.; Bliss, Mary; Myers, Tanya L.; Johnson, Timothy J.; Tiwald, Thomas E.

    2017-05-01

    The complex index of refraction, ñ = n + ik, has two components, n(ν) and k(ν), both a function of frequency, ν. The constant n is the real component, and k is the complex component, proportional to the absorption. In combination with other parameters, n and k can be used to model infrared spectra. However, obtaining reliable n/k values for solid materials is often difficult. In the past, the best results for n and k have been obtained from bulk, polished homogeneous materials free of defects; i.e. materials where the Fresnel equations are valid and there is no appreciable light scattering. Since it is often not possible to obtain such pure macroscopic samples, the alternative is to press the powder form of the material into a uniform disk. Recently, we have pressed such pellets from ammonium sulfate powder, and have measured the pellets' n and k values via two independent methods: 1) ellipsometry, which measures the changes in amplitude and phase of light reflected from the material of interest as a function of wavelength and angle of incidence, and 2) single-angle reflectance using a specular reflectance device within a Fourier transform infrared spectrometer. This technique measures the change in amplitude of light reflected from the material of interest as a function of wavelength over a wide spectral domain. The optical constants are determined from the single-angle measurements using the Kramers-Kronig relationship, whereas an oscillator model is used to analyze the ellipsometric measurements. The n(ν) and k(ν) values determined by the two methods were compared to previous values determined from single crystal samples from which transmittance and reflectance measurements were made and converted to n(ν) and k(ν) using a simple dispersion model. [Toon et al., Journal of Geophysical Research, 81, 5733-5748, (1976)]. Comparison with the literature values shows good agreement, indicating that these are promising techniques to measure the optical constants

  12. Timing of umbilical cord clamping of term infants.

    Science.gov (United States)

    Ceriani Cernadas, José María

    2017-04-01

    For at least over 200 years, multiple controversies have arisen around the timing of umbilical cord clamping. In the past decades, early cord clamping (within the first 15 seconds) had markedly prevailed. Only in the 21st century, randomized controlled trials have demonstrated the benefits of delayed cord clamping (at 2-3 minutes). Delayed cord clamping has been practiced in obstetrics based on the recommendations made by scientific societies and in systematic reviews, which have provided solid evidence to support this practice in term infants. This review describes the most relevant factors supporting the use of delayed cord clamping in term infants. It points out the essential role played by physiological mechanisms which, undoubtedly, allow us to understand the benefits of delayed cord clamping and advise us to wait for what nature has established. Other relevant aspects supporting delayed cord clamping are also described here. Sociedad Argentina de Pediatría.

  13. Establishing Age-Adjusted Reference Ranges for Iris-Related Parameters in Open Angle Eyes with Anterior Segment Optical Coherence Tomography.

    Directory of Open Access Journals (Sweden)

    Jeffrey R Peterson

    Full Text Available Define criteria for iris-related parameters in an adult open angle population as measured with swept source Fourier domain anterior segment optical coherence tomography (ASOCT.Ninety-eight eyes of 98 participants with open angles were included and stratified into 5 age groups (18-35, 36-45, 46-55, 56-65, and 66-79 years. ASOCT scans with 3D mode angle analysis were taken with the CASIA SS-1000 (Tomey Corporation, Nagoya, Japan and analyzed using the Anterior Chamber Analysis and Interpretation software. Anterior iris surface length (AISL, length of scleral spur landmark (SSL to pupillary margin (SSL-to-PM, iris contour ratio (ICR = AISL/SSL-to-PM, pupil radius, radius of iris centroid (RICe, and iris volume were measured. Outcome variables were summarized for all eyes and age groups, and mean values among age groups were compared using one-way analysis of variance. Stepwise regression analysis was used to investigate demographic and ocular characteristic factors that affected each iris-related parameter.Mean (±SD values were 2.24 mm (±0.46, 4.06 mm (±0.27, 3.65 mm (±0.48, 4.16 mm (±0.47, 1.14 (±0.04, 1.51 mm2 (±0.23, and 38.42 μL (±4.91 for pupillary radius, RICe, SSL-to-PM, AISL, ICR, iris cross-sectional area, and iris volume, respectively. Both pupillary radius (P = 0.002 and RICe (P = 0.027 decreased with age, while SSL-to-PM (P = 0.002 and AISL increased with age (P = 0.001. ICR (P = 0.54 and iris volume (P = 0.49 were not affected by age.This study establishes reference values for iris-related parameters in an adult open angle population, which will be useful for future studies examining the role of iris changes in pathologic states.

  14. Study for relation between direction of relativistic jet and optical polarization angle with multi-wavelength observation

    CERN Document Server

    Itoh, Ryosuke; Tanaka, Yasuyuki T; Uemura, Makoto; Kawabata, Koji S; Akitaya, Hiroshi; Kawaguchi, Kenji; Kanda, Yuka

    2015-01-01

    Blazars are thought to possess a relativistic jet that is pointing toward the direction of the Earth and the elect of relativistic beaming enhances its apparent brightness. They radiate in all wavebands from the radio to the gamma-ray bands via the synchrotron and the inverse Compton scattering process. Numerous observations are performed but the mechanism of variability, creation and composition of jets are still controversial. We performed multi-wavelength monitoring with optical polarization for 3C 66A, Mrk 421, CTA 102 and PMN J0948+0022 to investigate the mechanisms of variability and research the emission region in the relativistic jets. Consequently, an emergence of new emission component in flaring state is suggested in each object. The most significant aspect of these results is its wide range of sizes of emission regions from $10^{14}-10^{16}$ cm, which implies the model with a number of independent emission regions with variety sizes and randomly orientation. The "shock-in-jet" scenario can explain...

  15. Optical limiting in semiconductor-doped glasses

    Science.gov (United States)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1996-02-01

    We report optical limiting at 527 nm in two Schott semiconductor-doped glasses OG530 and OG515. These two glasses show quite contrasting nonlinear optical behaviour. The glass OG515 shows strong clamping while OG530 shows no clamping in optical limiting inspite of having much larger nonlinear refractive index. Similarly OG530 exhibits saturation of absorption while OG515 does not.

  16. Solution study of the Escherichia coli DNA polymerase III clamp loader reveals the location of the dynamic ψχ heterodimer

    Directory of Open Access Journals (Sweden)

    Farzaneh Tondnevis

    2015-09-01

    Full Text Available Several X-ray crystal structures of the E. coli core clamp loader containing the five core (δ′, δ, and three truncated γ subunits have been determined, but they lack the ψ and χ subunits. We report the first solution structure of the complete seven-subunit clamp loader complex using small angle X-ray scattering. This structure not only provides information about the location of the χ and ψ subunits but also provides a model of the dynamic nature of the clamp loader complex.

  17. Optimization of a clamped plate silencer.

    Science.gov (United States)

    Wang, Chunqi; Han, Jun; Huang, Lixi

    2007-02-01

    A previous theoretical study [L. Huang, J. Acoust. Soc. Am. 119, 2628-2638 (2006)] shows that, in a duct, a simply supported plate covering a side-branch rigid cavity can function effectively as a wave reflector over a broad range of low to medium frequencies. In this study, analytical formulation is extended to the boundary condition of clamped plate, which is easier to implement in practice. The theoretical model is tested experimentally using balsawood, which has a very high stiffness to mass ratio. The spectral peaks and shapes of the measured TL are in agreement with those calculated theoretically, attempts are also made to account for the considerable sound absorption in the rig. Further numerical studies based on the validated model show that, for a uniform plate, the optimal stopband is narrower and the lower band limit is worse than that of the simply supported configuration. However, a wave reflector using nonuniform, clamped plates with thinner ends out-performs the simply supported configuration in every aspect. Analyses show that the improvement is attributed to the increased acoustic radiation efficiency over the bulk length of the nonuniform plate, which behaves more like a rigid plate.

  18. The effect of solar zenith angle on MODIS cloud optical and microphysical retrievals within marine liquid water clouds

    Science.gov (United States)

    Grosvenor, D. P.; Wood, R.

    2014-07-01

    In this paper we use a novel observational approach to investigate MODIS satellite retrieval biases of τ and re (using three different MODIS bands: 1.6, 2.1 and 3.7 μm, denoted as re1.6, re2.1 and re3.7, respectively) that occur at high solar zenith angles (θ0) and how they affect retrievals of cloud droplet concentration (Nd). Utilizing the large number of overpasses for polar regions and the diurnal variation of θ0 we estimate biases in the above quantities for an open ocean region that is dominated by low level stratiform clouds. We find that the mean τ is fairly constant between θ0 = 50° and ~65-70°, but then increases rapidly with an increase of over 70 % between the lowest and highest θ0. The re2.1 and re3.7 decrease with θ0, with effects also starting at around θ0 = 65-70°. At low θ0, the re values from the three different MODIS bands agree to within around 0.2 μm, whereas at high θ0 the spread is closer to 1 μm. The percentage changes of re with θ0 are considerably lower than those for τ, being around 5 % and 7% for re2.1 and re3.7. For re1.6 there was very little change with θ0. Evidence is provided that these changes are unlikely to be due to any physical diurnal cycle. The increase in τ and decrease in re both contribute to an overall increase in Nd of 40-70% between low and high θ0. Whilst the overall re changes are quite small, they are not insignificant for the calculation of Nd; we find that the contributions to Nd biases from the τ and re biases were roughly comparable for re3.7, although for the other re bands the τ changes were considerably more important. Also, when considering only the clouds with the more heterogeneous tops, the importance of the re biases was considerably enhanced for both re2.1 and re3.7. When using the variability of 1 km resolution τ data (γτ) as a heterogeneity parameter we obtained the expected result of increasing differences in τ between high and low θ0 as heterogeneity increased, which was

  19. Correlation Between Humphrey Visual Field, Optical Coherence Tomography and Heidelberg Retina Tomograph Parameters in Primary Open-Angle Glaucoma, Normal-Tension Glaucoma and Ocular Hypertension

    Directory of Open Access Journals (Sweden)

    Ziya Ayhan

    2011-06-01

    Full Text Available Purpose: To evaluate the correlation of Humphrey visual field (VF parameters (MD and PSD with Heidelberg Retina Tomograph (HRT 3 and Stratus optical coherence tomography (OCT parameters in patients with primary open-angle glaucoma (POAG, normal-tension glaucoma (NTG and ocular hypertension (OHT. Material and Method: Fifty-five eyes of 29 POAG patients, 32 eyes of 16 OHT patients and 26 eyes of 13 NTG patients were enrolled in the study prospectively. Humphrey visual field test as well as optic nerve head and retinal nerve fiber layer (RNFL thickness analysis with HRT 3 and Stratus OCT were performed in all patients; the measurements were repeated every 6 months. Results: The mean age of the patients was 66.4±10.0 years and the mean follow-up time was 22±2.2 months. In POAG and NTG groups, MD and PSD correlated with all analyzed parameters in HRT, except for the height variation contour (HVC. In POAG group, MD and PSD values correlated with all analyzed parameters in OCT, except for the rim area (RA. In NTG group, correlation was found between MD values and all parameters in OCT. In NTG group, PSD correlated with all parameters in OCT, except for the RNFL thickness. In OHT group, no correlation was found between MD, PSD values and HRT parameters. In OHT group, only RA values in OCT correlated with MD and PSD. In all groups, there was no statistically significant difference between the first and last examinations for MD and PSD values and for the mean RNFL thickness measured with OCT and HRT. Discussion: In our study, it was found that in POAG and NTG patients, there was a general correlation of Humphrey VF parameters with HRT 3 and Stratus OCT parameters. (Turk J Ophthalmol 2011; 41: 143-50

  20. Efficiency of frequency conversion of high power laser and KDP crystal clamping method

    Science.gov (United States)

    Yan, Han; Du, Weifeng; Pei, Guoqing; Qin, Tinghai; Ye, Lang; Xu, Xu

    2017-05-01

    In the high power solid laser driver, the frequency conversion unit is of strict requirement to meet the drive condition of ICF. The performance of large caliber KDP crystal, which is the core of frequency conversion of laser, is a vital aspect affecting the overall technical index of the laser driver. In order to get a higher efficiency of frequency conversion, KDP crystal must keep a better surface condition, which asks for high-quality assemblage and adjustment. The current method used in engineering has insufficient knowledge and recognition on surface deformation control of the crystal. Meanwhile, the method itself is of low efficiency on clamping, and lacks of protection for the crystal. Thus, in this article an investigation of crystal clamping method with lower force was performed, factors affecting the surface of crystal were explored, through both imitation and experiment. The clamping method was redesigned and the frequency conversion efficiency was tested. Meanwhile, with the new method, clamping efficiency increases, the optical performance of crystals improves, and the crystals get better protection.

  1. Obstetricians' attitudes and beliefs regarding umbilical cord clamping.

    Science.gov (United States)

    Jelin, Angie C; Kuppermann, Miriam; Erickson, Kristine; Clyman, Ronald; Schulkin, Jay

    2014-09-01

    Although delayed umbilical cord clamping has been demonstrated to reduce the incidence of intraventricular hemorrhage and neonatal sepsis, and decrease the need for neonatal transfusions (without affecting cord pH, Apgar scores or the need for phototherapy), the extent to which this practice is being employed is unknown. We conducted a survey of US obstetricians to assess their attitudes and beliefs about cord clamping. Questionnaires were randomly mailed to members of the American College of Obstetricians and Gynecologists (ACOG), and the Collaborative Ambulatory Research Network (CARN). The data were analyzed using Chi-square and Student t tests. The response rates for the CARN and other ACOG members were 47% and 21%, respectively. Most (88%) responders reported their hospital had no umbilical cord clamping policy. The most frequent response for optimal timing of umbilical cord clamping, regardless of gestational age, was "don't know". Potential for neonatal red blood cell transfusion was the only concern cited as a reason for being somewhat or very inclined to delay umbilical cord clamping (51%). Delayed neonatal resuscitation (76%) was listed as a reason to clamp the cord immediately, despite the paucity of literature to support immediate cord clamping in this cohort. Despite substantial evidence supporting the practice of delayed cord clamping, few institutions have policies regarding this practice. Moreover, obstetricians' beliefs about the appropriate timing for umbilical cord clamping are not consistent with the evidence that demonstrates its beneficial impact on neonatal outcomes.

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

    Science.gov (United States)

    Xodo, Serena; Xodo, Luigi; Berghella, Vincenzo

    2017-09-16

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

  3. Dynamic and static control of the optical phase of guided p-polarized light for near-field focusing at large angles of incidence

    CERN Document Server

    Huang, Danhong; Wellems, L David; Mozer, Henry; Gumbs, Godfrey; Cardimona, D A; Maradudin, A A

    2013-01-01

    Both dynamic and static approaches are proposed and investigated for controlling the optical phase of a p-polarized light wave that is guided through a surface-patterned metallic structure with subwavelength features. For dynamic control, field-induced transparency (FIT) from photo-excited electrons in a slit-embedded atomic system show up within a narrow frequency window for modulating the intensity of focused transmitted light in the near-field region. Based on the electromagnetic coupling, this is facilitated by surface plasmons between the two FIT-atom embedded slits. For static control, the role of surface curvature is obtained for focused transmitted light passing through a Gaussian-shaped metallic microlens embedded with a linear array of slits, in addition to a negative light-refraction pattern, which is associated with higher-diffraction modes of light, under a large angle of incidence in the near-field region. Most interesting, however, this anomalous negative light-refraction pattern becomes suppre...

  4. Thermal stiffening of clamped elastic ribbons

    Science.gov (United States)

    Wan, Duanduan; Nelson, David R.; Bowick, Mark J.

    2017-07-01

    We use molecular dynamics to study the vibrations of a thermally fluctuating two-dimensional elastic membrane clamped at both ends. We directly extract the eigenmodes from resonant peaks in the frequency domain of the time-dependent height and measure the dependence of the corresponding eigenfrequencies on the microscopic bending rigidity of the membrane, taking care also of the subtle role of thermal contraction in generating a tension when the projected area is fixed. At finite temperatures we show that the effective (macroscopic) bending rigidity tends to a constant as the bare bending rigidity vanishes, consistent with theoretical arguments that the large-scale bending rigidity of the membrane arises from a strong thermal renormalization of the microscopic bending rigidity. Experimental realizations include covalently bonded two-dimensional atomically thin membranes such as graphene and molybdenum disulfide or soft matter systems such as the spectrin skeleton of red blood cells or diblock copolymers.

  5. Research and development of a self-centering clamping device for deep-water multifunctional pipeline repair machinery

    Directory of Open Access Journals (Sweden)

    Liquan Wang

    2016-01-01

    Full Text Available When multifunctional pipeline repair machinery (MPRM is used in the deep sea area, it is difficult to grip the pipeline and ensure concentricity between the cutter heads and the pipeline during its operation. In view of this, a new system of two-arm holding self-centering pipeline clamping device was proposed. The system is composed of two groups of parallelogram double-rocker mechanism and cranking block mechanism which are symmetrically distributed on the frame. The geometric parameter solutions of the clamping device were analyzed with motion and transmission as the constraints. A mechanical model was established to associate the friction torque of clamping points with the driving force. Clamping device and machinery were designed and manufactured for the Ø304.8–457.2 mm pipelines used in this test. ADAMS simulation experiments were conducted underwater, and the cutting and beveling tests were carried out onshore. The following results are achieved. First, the smaller the pipe diameter, the smaller the transmission angle of the oscillating slider mechanism; the longer the hydraulic cylinder stroke, the greater the transmission angle of the double rocker mechanism. Second, the driving force of the clamping device increases with the increase of the pipe diameter. When the diameter reaches 457.2 mm, the hydraulic cylinder driving force of the clamping device should be greater than 10219 N. Third, the feed rate of the cutters increases suddenly due to the slight shaking of the machinery which occurs at the beginning of the pipe cutting, so it is necessary to adopt a small feed rate. And fourth, onshore experiment results agree well with the theoretical design and simulation results, proving the rationality of the system. The research results in this paper provide technical basis for the research and development of similar engineering prototypes.

  6. The PCNA-RFC families of DNA clamps and clamp loaders.

    Science.gov (United States)

    Majka, Jerzy; Burgers, Peter M J

    2004-01-01

    The proliferating cell nuclear antigen PCNA functions at multiple levels in directing DNA metabolic pathways. Unbound to DNA, PCNA promotes localization of replication factors with a consensus PCNA-binding domain to replication factories. When bound to DNA, PCNA organizes various proteins involved in DNA replication, DNA repair, DNA modification, and chromatin modeling. Its modification by ubiquitin directs the cellular response to DNA damage. The ring-like PCNA homotrimer encircles double-stranded DNA and slides spontaneously across it. Loading of PCNA onto DNA at template-primer junctions is performed in an ATP-dependent process by replication factor C (RFC), a heteropentameric AAA+ protein complex consisting of the Rfc1, Rfc2, Rfc3, Rfc4, and Rfc5 subunits. Loading of yeast PCNA (POL30) is mechanistically distinct from analogous processes in E. coli (beta subunit by the gamma complex) and bacteriophage T4 (gp45 by gp44/62). Multiple stepwise ATP-binding events to RFC are required to load PCNA onto primed DNA. This stepwise mechanism should permit editing of this process at individual steps and allow for divergence of the default process into more specialized modes. Indeed, alternative RFC complexes consisting of the small RFC subunits together with an alternative Rfc1-like subunit have been identified. A complex required for the DNA damage checkpoint contains the Rad24 subunit, a complex required for sister chromatid cohesion contains the Ctf18 subunit, and a complex that aids in genome stability contains the Elg1 subunit. Only the RFC-Rad24 complex has a known associated clamp, a heterotrimeric complex consisting of Rad17, Mec3, and Ddc1. The other putative clamp loaders could either act on clamps yet to be identified or act on the two known clamps.

  7. Advanced patch-clamp techniques and single-channel analysis

    NARCIS (Netherlands)

    Biskup, B; Elzenga, JTM; Homann, U; Thiel, G; Wissing, F; Maathuis, FJM

    1999-01-01

    Much of our knowledge of ion-transport mechanisms in plant cell membranes comes from experiments using voltage-clamp. This technique allows the measurement of ionic currents across the membrane, whilst the voltage is held under experimental control. The patch-clamp technique was developed to study t

  8. Studying mechanosensitive ion channels with an automated patch clamp

    NARCIS (Netherlands)

    Barthmes, Maria; Jose, Mac Donald F; Birkner, Jan Peter; Brüggemann, Andrea; Wahl-Schott, Christian; Kocer, Armagan

    2014-01-01

    Patch clamp electrophysiology is the main technique to study mechanosensitive ion channels (MSCs), however, conventional patch clamping is laborious and success and output depends on the skills of the operator. Even though automated patch systems solve these problems for other ion channels, they cou

  9. Applications of alcohol clamping in early drug development

    NARCIS (Netherlands)

    Zoethout, Remco Wiebe Martijn

    2012-01-01

    This thesis describes the development of a novel alcohol clamp, a new method to obtain stable plasma levels of alcohol and its application in CNS-research. The method might have several advantages that were explored in subsequent studies described in this thesis. The stability of the alcohol clamp w

  10. OPTIMAL TIMING FOR CLAMPING THE UMBILICAL CORD AFTER BIRTH

    Science.gov (United States)

    Raju, Tonse N. K.; Singal, Nalini

    2013-01-01

    Synopsis This paper provides a brief overview of pros and cons of clamping the cord too early (within seconds) after birth. It also highlights evolving data that suggests that delaying cord clamping for 30–60 seconds after birth is beneficial to the baby and the mother, with no measurable negative effects. PMID:23164185

  11. 21 CFR 876.5160 - Urological clamp for males.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urological clamp for males. 876.5160 Section 876.5160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5160 Urological clamp for...

  12. Automated classification of single airborne particles from two-dimensional angle-resolved optical scattering (TAOS) patterns by non-linear filtering

    Science.gov (United States)

    Crosta, Giovanni Franco; Pan, Yong-Le; Aptowicz, Kevin B.; Casati, Caterina; Pinnick, Ronald G.; Chang, Richard K.; Videen, Gorden W.

    2013-12-01

    Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized airborne particles. In general, the interpretation of these patterns and the retrieval of the particle refractive index, shape or size alone, are difficult problems. By reformulating the problem in statistical learning terms, a solution is proposed herewith: rather than identifying airborne particles from their scattering patterns, TAOS patterns themselves are classified through a learning machine, where feature extraction interacts with multivariate statistical analysis. Feature extraction relies on spectrum enhancement, which includes the discrete cosine FOURIER transform and non-linear operations. Multivariate statistical analysis includes computation of the principal components and supervised training, based on the maximization of a suitable figure of merit. All algorithms have been combined together to analyze TAOS patterns, organize feature vectors, design classification experiments, carry out supervised training, assign unknown patterns to classes, and fuse information from different training and recognition experiments. The algorithms have been tested on a data set with more than 3000 TAOS patterns. The parameters that control the algorithms at different stages have been allowed to vary within suitable bounds and are optimized to some extent. Classification has been targeted at discriminating aerosolized Bacillus subtilis particles, a simulant of anthrax, from atmospheric aerosol particles and interfering particles, like diesel soot. By assuming that all training and recognition patterns come from the respective reference materials only, the most satisfactory classification result corresponds to 20% false negatives from B. subtilis particles and classification method may be adapted into a real-time operation technique, capable of detecting and characterizing micron-sized airborne particles.

  13. Clamping of ferroelectric and antiferromagnetic order parameters of YMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hanamura, Eiichi [Chitose Institute of Science and Technology, 758-65 Bibi, Chitose, Hokkaido (Japan); Hagita, Katsumi [Japan Science and Technology Corporation (CREST), 758-65 Bibi, Chitose, Hokkaido (Japan); Tanabe, Yukito [Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo (Japan)

    2003-01-29

    It was observed that a ferroelectric domain boundary (DB) is always accompanied by an antiferromagnetic DB in hexagonal YMnO{sub 3}, by means of interference effects of the second-harmonic signal. The clamping of these two order parameters at the ferroelectric DB is shown theoretically to originate from Dzyaloshinski-Moriya interaction. This interaction favouring a right angle between the neighbouring spins is found to be operative within the DB and to reverse the direction of the spins across the ferroelectric DB. (letter to the editor)

  14. On the use of Cu:Be clamp cells in magnetization and neutron scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Pfleiderer, C [Physikalisches Institut, Universitaet Karlsruhe, D-76128 Karlsruhe (Germany); Huxley, A D [DRFMC-SPSMS, CEA Grenoble, F-38054 Grenoble Cedex 9 (France); Hayden, S M [HH Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

    2005-10-12

    The use of miniature clamp cells made of Cu:Be for magnetization and neutron scattering studies in the medium pressure range is reviewed by giving recent results achieved in studies of UGe{sub 2}, MnSi and ZrZn{sub 2}. The experiments reviewed here establish in particular that small samples can be studied rather well at high pressures using a variety of different techniques, notably conventional diffraction, cold and thermal neutron triple axes and small-angle neutron scattering.

  15. Gain Clamped Two-Stage Double-Pass L-Band EDFA with a Single Fibre Bragg Grating

    Institute of Scientific and Technical Information of China (English)

    Sulaiman Wadi Harun; Harith Ahmad

    2004-01-01

    A gain clamping is demonstrated in a two-stage double-pass L-band erbium-doped fibre amplifier (EDFA) by using a single fibre Bragg grating. Two types of the fibre-Bragg-grating (FBG) broadband and narrowband have been used in the gain-clamped system. The combinatiox of the FBG and the optical circulator has created a laser in the cavity for gain clamping. The application ora broadband FBG has improved the amplifier's efficiency and noise figure compared to the narrowband FBG system. The gain is clamped at about 22.1 dB for the amplifier with broadband FBG with gain variation of less than ±0.15 dB and the input saturation power Psat at -8 dBm.The gain varies from 19.0 to 25.4dB in the signal wavelength region of 1574nm-1604nm. The noise figure varies from 6.0 to 10. 8dB at this wavelength range. The noise figure values are found to improve by as much as 0.3-1.1 dB when compared to the unclamped amplifier for signal wavelengths above 1580nm. The high clamped gain and low noise figure are obtained due to the suppression of the backward C-band amplified spontaneous emission. The gain clamped amplifier shows only a small power excursions when three of the four channels are added/dropped. The effects of relaxation oscillation are not seen for the gain-clamped two-stage double-pass L-band EDFA.

  16. Trends in Aortic Clamp Use During Coronary Artery Bypass Surgery: The Effect of Aortic Clamping Strategies on Neurologic Outcomes

    Science.gov (United States)

    Daniel, William T.; Kilgo, Patrick; Puskas, John D.; Thourani, Vinod H.; Lattouf, Omar M.; Guyton, Robert A.; Halkos, Michael E.

    2013-01-01

    Objective The purpose of this study was to determine the impact of different clamping strategies during CABG on the incidence of postoperative stroke. Methods In this case-control study, all patients at Emory hospitals from 2002–2009 with postoperative stroke after isolated CABG (N=141) were matched 1:4 to a contemporaneous cohort of patients without postoperative stroke (N=565). Patients were matched according to the Society of Thoracic Surgeons (STS) Predicted Risk of Postoperative Stroke (PROPS), which is based on 26 variables. On- (ONCAB) and off-pump (OPCAB) patients were matched separately. Multiple logistic regression analysis with adjusted odds ratios (OR) was performed to identify operative variables associated with postoperative stroke. Results Among the ONCAB cohort, the single cross-clamp technique was associated with a decreased risk of stroke compared to the double clamp (cross clamp + partial clamp) technique (OR=0.385, p=0.044). Within the OPCAB cohort, there was no significant difference in stroke according to clamp use. Epiaortic ultrasound of the ascending aorta increased from 45.3% in 2002 to 89.4% in 2009. From 2002–2009, clamp use decreased from 97.7% of cases to 72.7%. Conclusions During ONCAB, the use of a single cross-clamp compared to the double clamp technique decreases the risk of postoperative stroke. The use of any aortic clamp has decreased and epiaortic ultrasound use has increased from 2002–2009, indicating a change in operative technique and surgeon awareness of the potential complications associated with manipulation of the aorta. PMID:23477689

  17. Committee Opinion No. 684: Delayed Umbilical Cord Clamping After Birth.

    Science.gov (United States)

    2017-01-01

    Delayed umbilical cord clamping appears to be beneficial for term and preterm infants. In term infants, delayed umbilical cord clamping increases hemoglobin levels at birth and improves iron stores in the first several months of life, which may have a favorable effect on developmental outcomes. There is a small increase in jaundice that requires phototherapy in this group of infants. Consequently, health care providers adopting delayed umbilical cord clamping in term infants should ensure that mechanisms are in place to monitor for and treat neonatal jaundice. In preterm infants, delayed umbilical cord clamping is associated with significant neonatal benefits, including improved transitional circulation, better establishment of red blood cell volume, decreased need for blood transfusion, and lower incidence of necrotizing enterocolitis and intraventricular hemorrhage. Delayed umbilical cord clamping was not associated with an increased risk of postpartum hemorrhage or increased blood loss at delivery, nor was it associated with a difference in postpartum hemoglobin levels or the need for blood transfusion. Given the benefits to most newborns and concordant with other professional organizations, the American College of Obstetricians and Gynecologists now recommends a delay in umbilical cord clamping in vigorous term and preterm infants for at least 30-60 seconds after birth. The ability to provide delayed umbilical cord clamping may vary among institutions and settings; decisions in those circumstances are best made by the team caring for the mother-infant dyad.

  18. Effect of delayed umbilical cord clamping on blood gas analysis.

    Science.gov (United States)

    Valero, Javier; Desantes, Domingo; Perales-Puchalt, Alfredo; Rubio, Juan; Diago Almela, Vicente J; Perales, Alfredo

    2012-05-01

    To ascertain if there are differences in umbilical cord blood gas analysis between immediate and delayed cord clamping. In a prospective observational study on 60 vaginally delivered healthy term newborns, we sampled umbilical cord blood immediately after delivery and at the time umbilical cord pulsation spontaneously ceased. There were significant decreases in pH, oxygen saturation (sO(2)), glycemia, oxygen content (ctO(2)), bicarbonate (HCO(3)(-)) and base excess (BE). Lactate and [Formula: see text] increased. Delayed cord clamping pH correlated with immediate cord clamping pH, [Formula: see text] , ctHb, sO(2) and time (r(2)=0.77, pcord clamping lactate was associated with immediate cord clamping lactate and time (r(2)=0.83, pcord clamping alters acid-base parameters and lactate values compared to immediate cord clamping. Those variations depend mainly on time, prior pH and lactate. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. Single electrode dynamic clamp with StdpC.

    Science.gov (United States)

    Samu, David; Marra, Vincenzo; Kemenes, Ildiko; Crossley, Michael; Kemenes, György; Staras, Kevin; Nowotny, Thomas

    2012-10-15

    Dynamic clamp is a powerful approach for electrophysiological investigations allowing researchers to introduce artificial electrical components into target neurons to simulate ionic conductances, chemical or electrotonic inputs or connections to other cells. Due to the rapidly changing and potentially large current injections during dynamic clamp, problematic voltage artifacts appear on the electrode used to inject dynamic clamp currents into a target neuron. Dynamic clamp experiments, therefore, typically use two separate electrodes in the same cell, one for recording membrane potential and one for injecting currents. The requirement for two independent electrodes has been a limiting factor for the use of dynamic clamp in applications where dual recordings of this kind are difficult or impossible to achieve. The recent development of an active electrode compensation (AEC) method has overcome some of these prior limitations, permitting artifact-free dynamic clamp experimentation with a single electrode. Here we describe an AEC method for the free dynamic clamp software StdpC. The AEC component of StdpC is the first such system implemented for the use of non-expert users and comes with a set of semi-automated configuration and calibration procedures that facilitate its use. We briefly introduce the AEC method and its implementation in StdpC and then validate it with an electronic model cell and in two different biological preparations.

  20. Avoiding aortic clamping during CABG reduces postoperative stroke

    Science.gov (United States)

    Moss, Emmanuel; Puskas, John D; Thourani, Vinod H; Kilgo, Patrick; Chen, Edward P; Leshnower, Bradley G; Lattouf, Omar M; Guyton, Robert A.; Glas, Kathryn E; Halkos, Michael E.

    2014-01-01

    Objective The purpose of this study was to determine whether the incidence of postoperative stroke (PS) could be reduced by eliminating aortic clamping during CABG. Methods From 2002–2013, 12,079 patients underwent primary, isolated CABG at a single US academic institution. Aortic manipulation was completely avoided by using in-situ internal mammary arteries for inflow in 1,552 (12.9%) patients (no-touch), a clampless facilitating device (CFD) was used for proximal anastomoses in 1,548 (12.8%) patients, and aortic clamping was used in 8,979 (74.3%) patients. These strategies were assessed in a logistic regression model controlling for relevant variables. Results The overall incidence of PS was 1.4% (n=165), with an unadjusted incidence of 0.6% (n=10) in the no-touch group, 1.2% (n=18) in the CFD group, and 1.5% (n=137) in the clamp group (p<0.01 for no-touch vs clamp). The ratio of observed to expected stroke rate increased as the degree of aortic manipulation increased, from 0.48 in the no-touch group, to 0.61 in the CFD group, and 0.95 in the clamp group. Aortic clamping was independently associated with an increase in PS compared to a no-touch technique (AOR 2.50, p<0.01). When separated by CPB utilization, both the off-pump partial clamp and on-pump cross-clamp techniques increased the risk of PS compared to no-touch (AOR 2.52, p<0.01 and AOR 4.25, p<0.001, respectively). Conclusion A no-aortic touch technique has the lowest risk for postoperative stroke for patients undergoing CABG. Clamping the aorta during CABG increases the risk of PS, regardless of the severity of aortic disease. PMID:25293356

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

    Directory of Open Access Journals (Sweden)

    Amir-Mohammad Armanian

    2017-05-01

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

  2. Wide-angle imaging system with fiberoptic components providing angle-dependent virtual material stops

    Science.gov (United States)

    Vaughan, Arthur H. (Inventor)

    1993-01-01

    A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180 deg strip or arc of a target image. Light received by the spherical mirror section is reflected to a frustoconical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180 deg strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.

  3. Integral transform solutions of dynamic response of a clamped-clamped pipe conveying fluid

    Energy Technology Data Exchange (ETDEWEB)

    Gu Jijun; An Chen [Ocean Engineering Program, COPPE, Universidade Federal do Rio de Janeiro, CP 68508, Rio de Janeiro 21941-972 (Brazil); Duan Menglan [Offshore Oil/Gas Research Center, China University of Petroleum, Beijing 102249 (China); Levi, Carlos [Ocean Engineering Program, COPPE, Universidade Federal do Rio de Janeiro, CP 68508, Rio de Janeiro 21941-972 (Brazil); Su Jian, E-mail: sujian@nuclear.ufrj.br [Nuclear Engineering Program, COPPE, Universidade Federal do Rio de Janeiro, CP 68509, Rio de Janeiro 21941-972 (Brazil)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Dynamic response of pipe conveying fluid was studied numerically. Black-Right-Pointing-Pointer The generalized integral transform technique (GITT) was applied. Black-Right-Pointing-Pointer Numerical solutions with automatic global accuracy control were obtained. Black-Right-Pointing-Pointer Excellent convergence behavior was shown. Black-Right-Pointing-Pointer Modal separation analysis was carried out and the influence of mass ratio was analyzed. - Abstract: Analysis of dynamic response of pipe conveying fluid is an important aspect in nuclear power plant design. In the present paper, dynamic response of a clamped-clamped pipe conveying fluid was solved by the generalized integral transform technique (GITT). The governing partial differential equation was transformed into a set of second-order ordinary differential equations which is then numerically solved by making use of the subroutine DIVPAG from IMSL Library. A thorough convergence analysis was performed to yield sets of reference results of the transverse deflection at different time and spanwise position. We found good agreement between the computed natural frequencies at mode 1-3 and those obtained by previous theoretical study. Besides, modal separation analysis was carried out and the influence of mass ratio on deflection and natural frequencies was qualitatively and quantitatively assessed.

  4. Dynamic Study of a Capacitive MEMS Switch with Double Clamped-Clamped Microbeams

    Directory of Open Access Journals (Sweden)

    Hatem Samaali

    2014-01-01

    Full Text Available We study a capacitive MEMS switch composed of two clamped-clamped exible microbeams. We first develop a mathematical model for the MEMS switch where the upper microbeam represents the ground transmission line and the lower one represents the central transmission line. An electrostatic force is applied between the two microbeams to yield the switch to its ON and OFF states. We derive the equations of motion of the system and associated boundary conditions and solve the static and dynamic problems using the differential quadratic method. We show that using only nine grid points gives relatively accurate results when compared to those obtained using FEM. We also examine the transient behavior of the microswitch and obtain results indicating that subsequent reduction in actuation voltage, switching time, and power consumption are expected along with relatively good RF performances. ANSYS HFSS simulator is used in this paper to extract the RF characteristics of the microswitch. HFSS simulation results show that the insertion loss is as low as −0.31 dB and that the return loss is better than −12.41 dB at 10 GHz in the ON state. At the OFF state, the isolation is lower than −23 dB in the range of 10 to 50 GHz.

  5. Retinal nerve fiber layer in primary open-angle glaucoma with high myopia determined by optical coherence tomography and scanning laser polarimetry

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-en; WANG Xiao-yu; GU Yang-shun; HUANG Zhu

    2013-01-01

    Background Fundus changes associated with high myopia (HM) may mask those associated with primary open-angle glaucoma (POAG).This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM.The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated.Methods Twenty-two eyes with POAG and HM (spherical equivalent (SE) between-6.0 and-12.0 D) were evaluated,and 22 eyes with HM were used for comparison.Characteristic retinal nerve fiber layer (RNFL) thickness profiles in patients with POAG and HM were examined using optical coherence tomography (OCT) and scanning laser polarimetry with variable corneal compensation (GDxVCC),and the diagnostic capabilities of these imaging modalities were compared.RNFL parameters evaluated included superior average (Savg-GDx),inferior average (lavg-GDx),temporal-superior-nasal-inferior-temporal (TSNIT) average,and nerve fiber indicator (NFI) on GDxVCC and superior average (Savg-OCT),inferior average (lavg-OCT),nasal average (Navg-OCT),temporal average (Tavg-OCT),and average thickness (AvgThick-OCT) on OCT (fast RNFL scan).Visual field testing was performed and defects were evaluated using mean defect (MD) and pattern standard deviation (PSD).Results The RNFL parameters (P <0.05) significantly different between groups included Savg-GDx,lavg-GDx,TSNIT average,NFI,Savg-OCT,lavg-OCT,Tavg-OCT,and AvgThick-OCT.Significant correlations existed between TSNIT average and AvgThick-OCT (r=0.778),TSNIT average and MD (r=0.749),AvgThick-OCT and MD (r=0.647),TSNIT average and PSD (r=-0.756),and AvgThick-OCT and PSD (r=-0.784).The area under the receiver operating characteristic curve (AUROC) values of TSNIT average,Savg-GDx,lavg-GDx,NFI,Savg-OCT,lavg-OCT,Navg-OCT,Tavg-OCT,and AvgThick-OCT were 0.947,0.962,0.973,0.994,0.909,0.917,0.511,0.906,and 0.913,respectively.The NFI AUROC was the highest value.Conclusions RNFL

  6. Retinal nerve fiber layer in primary open-angle glaucoma with high myopia determined by optical coherence tomography and scanning laser polarimetry.

    Science.gov (United States)

    Wang, Xiao-en; Wang, Xiao-yu; Gu, Yang-shun; Huang, Zhu

    2013-01-01

    Fundus changes associated with high myopia (HM) may mask those associated with primary open-angle glaucoma (POAG). This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM. The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated. Twenty-two eyes with POAG and HM (spherical equivalent (SE) between -6.0 and -12.0 D) were evaluated, and 22 eyes with HM were used for comparison. Characteristic retinal nerve fiber layer (RNFL) thickness profiles in patients with POAG and HM were examined using optical coherence tomography (OCT) and scanning laser polarimetry with variable corneal compensation (GDxVCC), and the diagnostic capabilities of these imaging modalities were compared. RNFL parameters evaluated included superior average (Savg-GDx), inferior average (Iavg-GDx), temporal-superior-nasal- inferior-temporal (TSNIT) average, and nerve fiber indicator (NFI) on GDxVCC and superior average (Savg-OCT), inferior average (Iavg-OCT), nasal average (Navg-OCT), temporal average (Tavg-OCT), and average thickness (AvgThick-OCT) on OCT (fast RNFL scan). Visual field testing was performed and defects were evaluated using mean defect (MD) and pattern standard deviation (PSD). The RNFL parameters (P < 0.05) significantly different between groups included Savg-GDx, Iavg-GDx, TSNIT average, NFI, Savg-OCT, Iavg-OCT, Tavg-OCT, and AvgThick-OCT. Significant correlations existed between TSNIT average and AvgThick-OCT (r = 0.778), TSNIT average and MD (r = 0.749), AvgThick-OCT and MD (r = 0.647), TSNIT average and PSD (r = -0.756), and AvgThick-OCT and PSD (r = -0.784). The area under the receiver operating characteristic curve (AUROC) values of TSNIT average, Savg-GDx, Iavg-GDx, NFI, Savg-OCT, Iavg-OCT, Navg-OCT, Tavg-OCT, and AvgThick-OCT were 0.947, 0.962, 0.973, 0.994, 0.909, 0.917, 0.511, 0.906, and 0.913, respectively. The NFI AUROC was the

  7. A clamp-like biohybrid catalyst for DNA oxidation

    Science.gov (United States)

    van Dongen, Stijn F. M.; Clerx, Joost; Nørgaard, Kasper; Bloemberg, Tom G.; Cornelissen, Jeroen J. L. M.; Trakselis, Michael A.; Nelson, Scott W.; Benkovic, Stephen J.; Rowan, Alan E.; Nolte, Roeland J. M.

    2013-11-01

    In processive catalysis, a catalyst binds to a substrate and remains bound as it performs several consecutive reactions, as exemplified by DNA polymerases. Processivity is essential in nature and is often mediated by a clamp-like structure that physically tethers the catalyst to its (polymeric) template. In the case of the bacteriophage T4 replisome, a dedicated clamp protein acts as a processivity mediator by encircling DNA and subsequently recruiting its polymerase. Here we use this DNA-binding protein to construct a biohybrid catalyst. Conjugation of the clamp protein to a chemical catalyst with sequence-specific oxidation behaviour formed a catalytic clamp that can be loaded onto a DNA plasmid. The catalytic activity of the biohybrid catalyst was visualized using a procedure based on an atomic force microscopy method that detects and spatially locates oxidized sites in DNA. Varying the experimental conditions enabled switching between processive and distributive catalysis and influencing the sliding direction of this rotaxane-like catalyst.

  8. The cardiovascular effects of aortic clamping and unclamping

    African Journals Online (AJOL)

    An increase in the slope of the Ea line represents an increase in ... increase. (for example as the subject exercises), stroke work ... aortic clamping is that afterload and blood pressure increase ..... nitroglycerine does not increase heart rate nor.

  9. Delay in Clamping Umbilical Cord Benefits Babies, Doctors Say

    Science.gov (United States)

    ... doctors' group said. Although delayed clamping increases the newborn's risk of jaundice that will require treatment, ACOG said there's no evidence that waiting increases the mother's risk of hemorrhage. The guidelines are to be published in the ...

  10. Planar patch-clamp force microscopy on living cells

    Energy Technology Data Exchange (ETDEWEB)

    Pamir, Evren [Center for Nano Science, Ludwig-Maximilians University, Amalienstr 54, 80799 Munich (Germany); George, Michael; Fertig, Niels [Nanion Technologies GmbH, Erzgiessereistr. 4, 80335 Munich (Germany); Benoit, Martin [Center for Nano Science, Ludwig-Maximilians University, Amalienstr 54, 80799 Munich (Germany)], E-mail: martin.benoit@physik.uni-muenchen.de

    2008-05-15

    Here we report a new combination of the patch-clamp technique with the atomic force microscope (AFM). A planar patch-clamp chip microstructured from borosilicate glass was used as a support for mechanical probing of living cells. The setup not only allows for immobilizing even a non-adherent cell for measurements of its mechanical properties, but also for simultaneously measuring the electrophysiological properties of a single cell. As a proof of principle experiment we measured the voltage-induced membrane movement of HEK293 and Jurkat cells in the whole-cell voltage clamp configuration. The results of these measurements are in good agreement with previous studies. By using the planar patch-clamp chip for immobilization, the AFM not only can image non-adhering cells, but also gets easily access to an electrophysiologically controlled cellular probe at low vibrational noise.

  11. [Time of cord clamping and neonatal complications, a prospective study].

    Science.gov (United States)

    Rincón, D; Foguet, A; Rojas, M; Segarra, E; Sacristán, E; Teixidor, R; Ortega, A

    2014-09-01

    To assess the effects of early or late clamping of the umbilical cord in term newborns, assessing the levels of hemoglobin, hematocrit, and ferritin, and their correlation with some of the complications. A prospective study of healthy newborns at term or born by dystotic or eutocic delivery in our hospital between May 2009 until May 2010. Patients were assigned according to the time of clamping, group 1 (clamping (g1: 111 mg/dl, g2: 125 mg/dl, g3: 173 mg/dl; pcord clamping is associated with an increase in hematocrit, hemoglobin and ferritin at 48 hours of life, as well as an increased risk of polycythemia present with symptoms. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  12. Choosing the wire clamp microdrive for termosonic microwelding equipments

    Directory of Open Access Journals (Sweden)

    Lanin V. L.

    2010-06-01

    Full Text Available The article describes research of three types of wire clamp microdrive for termosonic microwelding equipment, covering an expanded range microconductors from 12,5 up to 75 mm. The most preferable, in the light of their high-speed and easy-programming qualities, proved to be the mechanisms of conductor clamp with piezoelement drives and the loading system based on "voice-coil" type electromagnet.

  13. Prehospital Emergency Inguinal Clamp Controls Hemorrhage in Cadaver Model

    Science.gov (United States)

    2013-07-01

    the CRoC preassembled for quick use. The clamp compresses the casualty’s tissues and is unat- tached to things like a litter. When screwed down, it is...for use on the battlefield to control difficult bleeds in the inguinal area. Study Design The study design was a sequence of experiments of clamp...temperature 4 hours before testing. The torso was rotated onto a wood block to intubate the aorta through a left thoracotomy incision. The thoracic aorta

  14. Lotus birth, a holistic approach on physiological cord clamping.

    Science.gov (United States)

    Zinsser, Laura A

    2017-09-04

    The positive effects of delayed cord clamping (DCC) has been extensively researched. DCC means: waiting at least one minute after birth before clamping and cutting the cord or till the pulsation has stopped. With physiological clamping and cutting (PCC) the clamping and cutting can happen at the earliest after the pulsation has stopped. With a Lotus birth, no clamping and cutting of the cord is done. A woman called Clair Lotus Day imitated the holistic approach of PCC from an anthropoid ape in 1974. The chimpanzee did not separate the placenta from the newborn. The aim of this case report is to discuss and learn a different approach in the third stage of labour. Three cases of Lotus birth by human beings were observed. All three women gave birth in an out-of-hospital setting and had ambulant postnatal care. The placenta was washed, salted and herbs were put on 2-3h post partum. The placenta was wrapped in something that absorbs the moisture. The salting was repeated with a degreasing frequency depending on moistness of the placenta. On life day six all three Lotus babies experiences a natural separation of the cord. All three Lotus birth cases were unproblematic, no special incidence occurred. One should differentiate between early cord clamping (ECC), delayed cord clamping (DCC) and physiological cord clamping (PCC). Lotus birth might lead to an optimisation of the bonding and attachment. Research is needed in the areas of both PCC and Lotus birth. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  15. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping) improves systemic and cerebral oxygenation in preterm lambs.

    Science.gov (United States)

    Polglase, Graeme R; Dawson, Jennifer A; Kluckow, Martin; Gill, Andrew W; Davis, Peter G; Te Pas, Arjan B; Crossley, Kelly J; McDougall, Annie; Wallace, Euan M; Hooper, Stuart B

    2015-01-01

    As measurement of arterial oxygen saturation (SpO2) is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known. We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs. Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping. Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping. The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  16. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping improves systemic and cerebral oxygenation in preterm lambs.

    Directory of Open Access Journals (Sweden)

    Graeme R Polglase

    Full Text Available As measurement of arterial oxygen saturation (SpO2 is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2 were measured continuously in apnoeic preterm lambs (126±1 day gestation. Positive pressure ventilation was initiated either 1 prior to umbilical cord clamping, or 2 after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

  17. Single mode variable-sensitivity fiber optic sensors

    Science.gov (United States)

    Murphy, K. A.; Fogg, B. R.; Gunther, M. F.; Claus, R. O.

    1992-01-01

    We review spatially-weighted optical fiber sensors that filter specific vibration modes from one dimensional beams placed in clamped-free and clamped-clamped configurations. The sensitivity of the sensor is varied along the length of the fiber by tapering circular-core, dual-mode optical fibers. Selective vibration mode suppression on the order of 10 dB was obtained. We describe experimental results and propose future extensions to single mode sensor applications.

  18. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  19. Umbilical cord clamping. An analysis of a usual neonatological conduct.

    Science.gov (United States)

    Papagno, L

    1998-01-01

    Here we described a critical analysis of the neonatological procedure of early cord clamping, meaning this, within 40 seconds after birth. Fifty three cases are here analysed, in which this practice was not performed, but instead a late umbilical cord clamping was done after birth or after the cord had stopped beating. Variations in hematocrito values within 24 to 36 hours after birth were studied. A transitory polycithemia, with a maximum peak 12 hours post-delivery was observed. These values returned to normal levels between 24 and 36 hours after birth. K vitamin was not administered to any of the newborns. No pathology appeared related to this transitory polycithemia. In can be concluded that the late umbilical cord clamping represents no risk to the new-born and that the pathological phenomena described under these circumstances may be attributed to the increase in K vitamin dependent coagulation factors that are induced by the routinary administration of phitonadione to all normal newborns.

  20. Arterial Clamping Increases Central Renal Cryoablation Efficacy: An Animal Study

    DEFF Research Database (Denmark)

    Nonboe, Lasse Larsen; Nielsen, Tommy Kjaergaard; Høyer, Søren;

    2017-01-01

    INTRODUCTION: The minimally invasive treatment of small renal masses with cryoablation has become increasingly widespread during the past 15 years. Studies with long-term follow-up are beginning to emerge, showing good oncological control, however, tumors with a central and endophytic location seem...... to possess an increased risk of treatment failure. Such tumors are likely to be subjected to a high volume of blood giving thermal protection to the cancerous cells. Arterial clamping during freezing might reduce this effect but at the same time subject the kidney to ischemia. The aim of this study...... was to evaluate the effect of renal artery clamping during cryoablation in a porcine survival model. METHODS: Ten Danish Landrace pigs (approximately 40 kg) underwent bilateral laparoscopic cryoablation with clamping of the right renal artery during freezing. The cryoablation consisted of a standard double...

  1. [Advantage of delayed umbilical cord clamping in the newborn infant].

    Science.gov (United States)

    Menget, A; Mougey, C; Thiriez, G; Riethmuller, D

    2013-09-01

    The timing of umbilical cord clamping remains controversial. Although most maternity wards use the early clamping (5-15s), randomized studies and meta-analyses have demonstrated the benefit of delayed clamping for term and preterm newborn infants over the past 10 years. Indeed, placentofetal transfusion of 20-30 ml/kg in 2-3 min improves the iron status of term infants and prevents infant hypochromic anemia. Infant anemia is a public health problem in many developing countries. For preterm newborns, placental transfusion for 45 s or milking the cord for 15 s improves cardiovascular adaptation, with better hemodynamic stability, as well as decreased intraventricular hemorrhages, need for transfusion, and late-onset sepsis. A new look at this symbolic act is needed and professionals need to be persuaded of the importance of the "wait a minute" policy for a better physiological delivery.

  2. Using physiology to guide time to cord clamping.

    Science.gov (United States)

    Kluckow, Martin; Hooper, Stuart B

    2015-08-01

    Immediate clamping and cutting of the umbilical cord at birth has been the accepted standard of care for decades. The physiologic rationale relating umbilical cord clamping (UCC) to the events of the circulatory transition is not considered in arbitrarily recommended cord clamping times. Systematic review of early versus deferred UCC shows significant hemodynamic benefits to the deferred group. Mechanisms for this protective effect are considered in this review. The original concept of a placental transfusion with a volume load and prevention of low cardiac output relies on the physiological end point of the amount of blood transfused. The newer concept of an ordered physiological transition is increasingly supported. This model places aeration of the lungs and an increase in pulmonary blood flow back at the centre of the circulatory transition with timing of UCC being related to establishment of respiration. The need for "physiologically based" UCC is discussed. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  3. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te studied by variable angle spectroscopic ellipsometry between 0.75 and 6.24 eV

    Energy Technology Data Exchange (ETDEWEB)

    Yao, H.W.; Erickson, J.C. [Univ. of Nebraska, Lincoln, NE (United States)]|[Sandia National Labs., Livermore, CA (United States); Barber, H.B. [Univ. of Arizona, Tucson, AZ (United States); James, R.B.; Hermon, H. [Sandia National Labs., Livermore, CA (United States)

    1999-06-01

    Cadmium zinc telluride (CZT) is a leading technological material for room-temperature gamma-ray and x-ray detectors. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were studied by variable angle spectroscopic ellipsometry (VASE). Measurements made by VASE were performed on CZT and CdTe samples in air at room temperature at multiple angles of incidence. A parametric function model was employed in the VASE analysis to determine the dielectric functions {epsilon} = {epsilon}{sub 1} + i{epsilon}{sub 2} in the range of 0.75 to 6.24 eV. A two-oscillator analytical model was used to describe the dielectric response of native oxides on CZT. Surface oxide optical properties and thickness on CZT were also determined in conjunction with the VASE measurement and analysis of a CdTe sample. Two samples of CZT of different oxide thicknesses were measured and their optical constants were coupled together in a multiple-sample, multiple-model VASE analysis to resolve correlations between fitting parameters. Effective medium approximation was used to describe the optical properties of the CZT oxide with roughness. A Kramers-Kronig self-consistency check of the real and imaginary parts of the Cd{sub 0.9}Zn{sub 0.1}Te dielectric functions was performed over the energy range 0.75 to 6.24 eV. A five-Lorentz-oscillator model was employed to describe the dielectric response of CZT in the range of 1.6 to 6.24 eV. Intensity transmission measurements were made on the Cd{sub 0.9}Zn{sub 0.1}Te and CdTe, showing the absorption energy band edges of {approximately}1.58 and 1.46 eV, respectively.

  4. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te studied by variable angle spectroscopic ellipsometry between 0.75 and 6.24 eV

    Energy Technology Data Exchange (ETDEWEB)

    Ralph B. James

    2000-01-07

    Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were studied by variable angle spectroscopic ellipsometry (VASE). Measurements made by VASE were performed on CZT and CdTe samples in air at room temperature at multiple angles of incidence. A parametric function model was employed in the VASE analysis to determine the dielectric functions {var_epsilon}={var_epsilon}{sub 1} + i{var_epsilon}{sub 2} in the range of 0.75 to 6.24 eV. A two-oscillator analytical model was used to describe the dielectric response of native oxides on CZT. Surface oxide optical properties and thickness on CZT were also determined in conjunction with the VASE measurement and analysis of a CdTe sample. Two samples of CZT of different oxide thicknesses were measured and their optical constants were coupled together in a multiple-sample, multiple-model VASE analysis to resolve correlations between fitting parameters. Effective medium approximation (EMA) was used to describe the optical properties of the CZT oxide with roughness. A Kramers-Kronig self-consistency check of the real and imaginary parts of the Cd{sub 0.9}Zn{sub 0.1} dielectric functions was performed over the energy range 0.75 to 6.24 eV. A five-Lorentz-oscillator model was employed to describe the dielectric response of CZT in the range of 1.6 to 6.24 eV. Intensity transmission measurements were made on the Cd{sub 0.9}Zn{sub 0.1}Te and CdTe, showing the absorption energy band edges of {approximately} 1.58 and 1.46 eV, respectively.

  5. New active load voltage clamp for HF-link converters

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.; Andersen, M.A.E.

    2005-07-01

    This paper proposes a new active clamp for HF-link converters, which features very high efficiency by returning the clamped energy back to the primary side through a small auxiliary converter. It also increases the reliability of HF-link converters by providing an alternative load current path during malfunctions of the secondary bidirectional bridge. The feasibility of the approach is shown on audio power amplifier prototype. New integrated magnetics design is presented that incorporates both the main power and auxiliary transformer on the same magnetic core. (au)

  6. Plasma temperature clamping in filamentation laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; Yeak, J.; Phillips, Mark C.

    2015-10-19

    Ultrafast laser filament induced breakdown spectroscopy is a very promising method for remote material detection. We present characteristics of plasmas generated in a metal target by laser filaments in air. Our measurements show that the temperature of the ablation plasma is clamped along the filamentation channel due to intensity clamping in a filament. Nevertheless, significant changes in radiation intensity are noticeable, and this is essentially due to variation in the number density of emitting atoms. The present results also partly explains the reason for the occurrence of atomic plume during fs LIBS in air compared to long-pulse ns LIBS.

  7. New active load voltage clamp for HF-link converters

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper proposes a new active clamp for HF-link converters, which features very high efficiency by returning the clamped energy back to the primary side through a small auxiliary converter. It also increases the reliability of HF-link converters by providing an alternative load current path du...... during malfunctions of the secondary bidirectional bridge. The feasibility of the approach is shown on audio power amplifier prototype. New integrated magnetics design is presented that incorporates both the main power and auxiliary transformer on the same magnetic core....

  8. The problem of isotropic rectangular plate with four clamped edges

    Indian Academy of Sciences (India)

    C Erdem İmrak; Ismail Gerdemeli

    2007-06-01

    The examination of the exact solution of the governing equation of the rectangular plate is important for many reasons. This report discusses in exact solution of the governing equation of an isotropic rectangular plate with four clamped edges. A numerical method for clamped isotropic rectangular plate under distributed loads and an exact solution of the governing equation in terms of trigonometric and hyperbolic function are given. Finally, an illustrative example is given and the results are compared with those reported earlier. This method is found to be easier and effective. The results show reasonable agreement with other available results, but with a simpler and practical approach.

  9. Total internal reflection without change of polarization using a right-angle prism with half-wavelength-thick optical interference coating.

    Science.gov (United States)

    Azzam, R M A

    2009-02-01

    Monochromatic light, which is polarized in an arbitrary state, is totally internally reflected at angle of incidence phi=45 degrees without change of polarization by a right-angle prism of refractive index n0=1+1/Square root of 2=1.70711 (e.g., N-LAK8 Schott glass at wavelength lambda=706 nm), which is coated with a transparent thin film of refractive index n1=(1+1/2)1/2=1.30656 (e.g., vacuum-deposited fluoride material) and of metric thickness equal to half of the vacuum wavelength of incident light, d=lambda/2. The ambient medium of evanescent refraction is assumed to be vacuum, air, or an inert gas. Wavelength shifts of +/-50 nm, or changes of the internal angle of incidence of +/-1 degrees around 45 degrees, cause phase errors of only a few degrees. The reflected and incident polarization states are nearly identical in the presence of such small phase errors.

  10. In vivo proton magnetic resonance spectroscopy (1H-MRS) evaluation of the metabolite concentration of optic radiation in primary open angle glaucoma

    Energy Technology Data Exchange (ETDEWEB)

    Sidek, Sabrilhakim [University of Malaya, Department of Biomedical Imaging, University Malaya Research Imaging Centre (UMRIC), Kuala Lumpur (Malaysia); Universiti Teknologi MARA, Medical Imaging Unit, Faculty of Medicine, Sg Buloh, Selangor (Malaysia); Ramli, Norlisah; Rahmat, Kartini; Kuo, Tan Li [University of Malaya, Department of Biomedical Imaging, University Malaya Research Imaging Centre (UMRIC), Kuala Lumpur (Malaysia); Ramli, Norlina Mohd; Abdulrahman, Fadzlina [University of Malaya, Department of Ophthalmology, Faculty of Medicine, Kuala Lumpur (Malaysia)

    2016-12-15

    To compare the metabolite concentration of optic radiation in glaucoma patients with that of healthy subjects using Proton Magnetic Resonance Spectroscopy (1H-MRS). 1H-MRS utilising the Single-Voxel Spectroscopy (SVS) technique was performed using a 3.0Tesla MRI on 45 optic radiations (15 from healthy subjects, 15 from mild glaucoma patients, and 15 from severe glaucoma patients). A standardised Volume of Interest (VOI) of 20 x 20 x 20 mm was placed in the region of optic radiation. Mild and severe glaucoma patients were categorised based on the Hodapp-Parrish-Anderson (HPA) classification. Mean and multiple group comparisons for metabolite concentration and metabolite concentration ratio between glaucoma grades and healthy subjects were obtained using one-way ANOVA. The metabolite concentration and metabolite concentration ratio between the optic radiations of glaucoma patients and healthy subjects did not demonstrate any significant difference (p > 0.05). Our findings show no significant alteration of metabolite concentration associated with neurodegeneration that could be measured by single-voxel 1H-MRS in optic radiation among glaucoma patients. (orig.)

  11. Optics

    CERN Document Server

    Fincham, W H A

    2013-01-01

    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  12. IVC CLAMP: infrahepatic inferior vena cava clamping during hepatectomy - a randomised controlled trial in an interdisciplinary setting

    Directory of Open Access Journals (Sweden)

    Reissfelder Christoph

    2009-10-01

    Full Text Available Abstract Background Intraoperative haemorrhage is a known predictor for perioperative outcome of patients undergoing hepatic resection. While anaesthesiological lowering of central venous pressure (CVP by fluid restriction is known to reduce bleeding during transection of the hepatic parenchyma its potential side effects remain poorly investigated. In theory it may have negative effects on kidney function and tissue perfusion and bears the risk to result in severe haemodynamic instability in case of profound intraoperative blood loss. The present randomised controlled trial evaluates efficacy and safety of infrahepatic inferior vena cava (IVC clamping as an alternative surgical technique to reduce CVP during hepatic resection. Methods/Design The proposed IVC CLAMP trial is a single-centre randomised controlled trial with a two-group parallel design. Patients and outcome-assessors are blinded for the treatment intervention. Patients undergoing elective hepatic resection due to any reason are enrolled in IVC CLAMP. All patients admitted to the Department of General-, Visceral-, and Transplant Surgery, University of Heidelberg for elective hepatic resection are consecutively screened for eligibility and written informed consent is obtained on the day before surgery. The primary objective of this trial is to assess and compare the amount of blood loss during hepatic resection in patients receiving surgical CVP reduction by clamping of the IVC as compared to anaesthesiological CVP without infrahepatic IVC clamping reduction. In addition to blood loss a set of general as well as surgical variables are analysed. Discussion This is a randomised controlled patient and observer blinded two-group parallel trial designed to assess efficacy and safety of infrahepatic IVC clamping during elective hepatectomy. Trial registration ClinicalTrials NCT00732979

  13. COMPARISON OF VIBRATION PERFORMANCE OF A SANDWICH CLAMPED-CLAMPED BEAM WITH MAGNETS VERSUS CONVENTIONAL CONSTRAINED DAMPING TREATMENTS

    Institute of Scientific and Technical Information of China (English)

    ZhengHuiming; HeZeng; LiMing; ZhaoGaoyu

    2004-01-01

    This paper investigates how the magnetic constrained layer damping (MCLD) treatment suppresses the displacement and acceleration resonant peak of a clamped-clamped beam. Because MCLI) treatment reduces input work and gives more dissipation energy, the vibration from external excitation can be effectively suppressed.The vibration reduction effects of MCLD and other conventional constrained damping treatments are also evaluated. In many cases, using MCLD treatments can yield smaller displacement and acceleration resonant peak especially in mode 1 compared to the other treatments without greatly changing the natural frequencies of the base beam.

  14. Haematological Parameters in Open Angle Glaucoma Patients ...

    African Journals Online (AJOL)

    GA Akinlabi, VI Iyawe. Abstract. There is potential for blood related factors to affect aqueous production or optic nerve functions. ... Here we compare hematological parameters for a group of 68 chronic open-angle glaucoma (OAG) patients and ...

  15. INOVASI SAMBUNGAN MEKANIS MENGGUNAKAN CLAMP BAJA UNTUK TULANGAN BETON

    Directory of Open Access Journals (Sweden)

    Parmo

    2015-12-01

    Full Text Available In the last few years, Indonesian urban growth has tends to be lead to the overground space. This was caused by the significant population increasement the lackness of land availability. The phenomenon is also marked with the increasing number of high-rise buildings and skyscrapers. However, high-rise buildings and skyscrapers have the potential dangers against earthquakes, even more Indonesia lay on an earthquake-prone areas. There are two main things that need to be considered in the planning of earthquake-resistant buildings, which is strength and ductility. Deformation capability and the connection strength between the reinforcement taken into consideration in the design of earthquake-resistant structures. From the steel clamp tensile test results for D13’s mechanical connection reinforcement, it gained 270.69 Mpa for yield strength, 351.45 MPa for ultimate tensile strength and 4757 kg for maximum load with 40% elongation. As for the D16’s mechanical connection reinforcement gained 217.80 MPa for yield strength, 327 605 MPa for ultimate tensile strength and 6717 kg for maximum load with 32% elongation. This study uses two pieces of steel clamp, but in order to obtain a better result then it need to be add more clamps while increasing the steel clamp material quality.

  16. Do not overlook an umbilical cord hernia before clamping.

    Science.gov (United States)

    Cizmeci, Mehmet Nevzat; Kanburoglu, Mehmet Kenan; Akelma, Ahmet Zulfikar; Tatli, Mustafa Mansur

    2013-08-01

    An umbilical cord hernia is a rare midline abdominal defect. These masses may be easily overlooked at birth, which may result in an intestinal injury due to careless proximal application of the cord clamp. Herein, we present a newborn infant with an umbilical cord hernia who was managed by primary closure of the lesion.

  17. A piezoelectric vibration harvester based on clamped-guided beams

    NARCIS (Netherlands)

    Wang, Z.; Matova, S.; Elfrink, R.; Jambunathan, M.; Nooijer, C. de; Schaijk, R. van; Vullers, R.J.M.

    2012-01-01

    The paper addresses the design, modeling, fabrication and experimental results of a piezoelectric energy harvester based on clamped-guided beams. The design is featured by shorter mass displacement and higher reliability than cantilever beams. Two separate sets of capacitors allow exploiting both te

  18. Tne stiffness of first-order and second-order modules assembled with extracortical clamp devices

    Directory of Open Access Journals (Sweden)

    F. K. Sabirov

    2015-01-01

    Full Text Available The extracortical clamp device (ECD is a tool used in external fixation which unlike the K-wires and half-pins don’t perforate cortical bone. The use of ECD is prospective for the treatment of periprosthetic femoral fractures and in the lengthening over nail and bone transport over nail. The data on the bench tests of the osteosynthesis rigidity by the external fixation first-order and second-order modules on the base of extracortical clamp devices are observed in the article. Materials and methods. The authors made 240 bench tests using torsional-vibration machine, Indicators measuring linear displacements with a scale of 0.01 mm, bone simulators («Sawbones», calibrated load, Ilizarov’s apparatus и extracortical fixators. The statistical analysis was performed with use software «STATISTICA» (ver. 6.0. The data obtained are presented in graphs «Box and Whisker Plot». Results. Among the investigated variants of first-order modules the better results of osteosynthesis rigidity were found in the module based on two ECD inserted at angle 60 degrees to each other and at distance of 10 cm from each other. Among the investigated second-order modules, better results of osteosynthesis rigidity were found in the module based on two ECD inserted at an angle 60 degrees to each other at distance of 10 cm from each other. Conclusion. Thus the tested modules can be used in practice in assemblies of external fixation devices in periprosthetic fractures, lengthening and bone transport over the nail.

  19. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  20. Reconstructing the Poynting vector skew angle and wave-front of optical vortex beams via two-channel moir\\'e deflectometery

    CERN Document Server

    Yeganeh, Mohammad; Dashti, Mohsen; Slussarenko, Sergei; Santamato, Enrico; Karimi, Ebrahim

    2013-01-01

    A novel approach based on the two-channel moir\\'e deflectometry has been used to measure both wave-front and transverse component of the Poynting vector of an optical vortex beam. Generated vortex beam by the q-plate, an inhomogeneous liquid crystal cell, has been analyzed with such technique. The measured topological charge of generated beams are in an excellent agreement with theoretical prediction.

  1. Accurate Measurements of Dielectric and Optical Functions of Liquid Water and Liquid Benzene in the VUV Region (1-100 eV) Using Small-Angle Inelastic X-ray Scattering.

    Science.gov (United States)

    Hayashi, Hisashi; Hiraoka, Nozomu

    2015-04-30

    Using a third-generation synchrotron source (the BL12XU beamline at SPring-8), inelastic X-ray scattering (IXS) spectra of liquid water and liquid benzene were measured at energy losses of 1-100 eV with 0.24 eV resolution for small momentum transfers (q) of 0.23 and 0.32 au with ±0.06 au uncertainty for q. For both liquids, the IXS profiles at these values of q converged well after we corrected for multiple scattering, and these results confirmed the dipole approximation for q ≤ ∼0.3 au. Several dielectric and optical functions [including the optical oscillator strength distribution (OOS), the optical energy-loss function (OLF), the complex dielectric function, the complex index of refraction, and the reflectance] in the vacuum ultraviolet region were derived and tabulated from these small-angle (small q) IXS spectra. These new data were compared with previously obtained results, and this comparison demonstrated the strong reproducibility and accuracy of IXS spectroscopy. For both water and benzene, there was a notable similarity between the OOSs of the liquids and amorphous solids, and there was no evidence of plasmon excitation in the OLF. The static structure factor [S(q)] for q ≤ ∼0.3 au was also deduced and suggests that molecular models that include electron correlation effects can serve as a good approximation for the liquid S(q) values over the full range of q.

  2. Four- year thyroidectomy procedures: Ligasure Vs. clamp & tie

    Directory of Open Access Journals (Sweden)

    Pazoki AR

    2010-01-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: The electrothermal bipolar vessel sealing system is an adjunct to the hemostatic technique, which has been successfully used in many abdominal operation, recently made available to thyroid surgery. The purpose of this was compare the outcomes of new hemostatic technique with traditional method of clamp and tie."n"nMethods: In this retrospective cross-sectional study has been done in surgery's wards of Milad & Rasul- Akram hospitals in Tehran, Iran. During three- year period between 2005-2008 all patients with different kind of pathology that need operation were assessed. Time duration of surgery and hospital stay and post surgery complication in two group, ligasure (n=45 and clamp & tie (n=145 were compared with each others."n"nResults: No difference was seen between two groups in time duration of surgery. Significant difference was seen in hospital stay and complications of surgery. Time of operation in Ligasure group was 132/22 minute and in clamp and tie group was 130/10 minute. There was found significant difference in duration of hospital stay and postoperative complication. Hypocalcemia were seen in two and 24 cases in Ligasure and Clamp & Tie group, respectively (p<0.05. Hospital stay was 2

  3. Timing of umbilical cord clamping: effect on iron endowment of the newborn and later iron status.

    Science.gov (United States)

    Chaparro, Camila M

    2011-11-01

    The optimal timing of umbilical cord clamping has been debated in the scientific literature for at least the last century, when cord clamping practices shifted from delayed towards immediate clamping. Recent research provides evidence for the beneficial effect of delayed cord clamping on infant iron status. The present review describes the physiological basis for the impact of cord clamping time on total body iron at birth and the relationship between birth body iron, as affected by cord clamping time, and iron status later in infancy. This research is discussed in the context of current clamping practices, which tend towards early cord clamping in most settings, as well as the high levels of anemia present in young infants in many countries worldwide. © 2011 International Life Sciences Institute.

  4. High-power, narrow-band, high-repetition-rate, 5.9 eV coherent light source using passive optical cavity for laser-based angle-resolved photoelectron spectroscopy.

    Science.gov (United States)

    Omachi, J; Yoshioka, K; Kuwata-Gonokami, M

    2012-10-08

    We demonstrate a scheme for efficient generation of a 5.9 eV coherent light source with an average power of 23 mW, 0.34 meV linewidth, and 73 MHz repetition rate from a Ti: sapphire picosecond mode-locked laser with an output power of 1 W. Second-harmonic light is generated in a passive optical cavity by a BiB(3)O(6) crystal with a conversion efficiency as high as 67%. By focusing the second-harmonic light transmitted from the cavity into a β-BaB(2)O(4) crystal, we obtain fourth-harmonic light at 5.9 eV. This light source offers stable operation for at least a week. We discuss the suitability of the laser light source for high-resolution angle-resolved photoelectron spectroscopy by comparing it with other sources (synchrotron radiation facilities and gas discharge lamp).

  5. Gigaseal formation in patch clamping with applications of nanotechnology

    CERN Document Server

    Malboubi, Majid

    2014-01-01

    This book presents an investigation of gigaseal formation using micro/nanotechnology. The aims of the book are twofold. First, it explains the mechanisms of gigaseal formation using the latest discoveries. Second, it provides practical techniques for frequent formation of high resistance seals. The formation of a high-resistance electrical seal, also known as a gigaseal, between a cell membrane and a glass micropipette tip is essential in patch-clamp experiments. Even though four decades have passed since the introduction of the patch-clamping technique by Neher and Sakmann, gigaseal formation remains an obstacle in developing the high-throughput ion channel screening systems required by the pharmaceutical industry. Here the authors share their latest methods for achieving gigaseal formation and describe techniques that are highly desirable at both research and industrial levels. Nanotechnology has been found to be a powerful tool for studying and modifying glass micropipettes and in tackling the problem of g...

  6. A new configuration for multilevel converters with diode clamped topology

    DEFF Research Database (Denmark)

    Nami, A.; Zare, F.; Ledwich, G.

    2008-01-01

    of load changes which can avoid neutral point balancing problem in such converters. In addition, the presented topology is suitable for renewable energy systems to boost the low rectified output-voltage. In order to verify the proposed topology, steady state analysis, modelling and simulations are carried......Due to the increased use of renewable energy and power elctronic applications, more multilevel converters (MLC) are developed. A Neutral Point Clamped (NPC) inverter is one of the most used multilevel topologies for wind turbine (WT) and photovoltaic (PV) applications. One of the most crucial...... points in this type of converter is dc-voltage control. In this paper, a novel multi output dc-dc converter connected to a diode clamped topology is presented. This converter, for a given duty cycles, is able to regulate the capacitor voltage to provide an appropriate input voltage for NPC regardless...

  7. Active energy recovery clamping circuit to improve the performance of power converters

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Bret; Barkley, Adam

    2017-05-09

    A regenerative clamping circuit for a power converter using clamping diodes to transfer charge to a clamping capacitor and a regenerative converter to transfer charge out of the clamping capacitor back to the power supply input connection. The regenerative converter uses a switch connected to the midpoint of a series connected inductor and capacitor. The ends of the inductor and capacitor series are connected across the terminals of the power supply to be in parallel with the power supply.

  8. A new angle on the Euler angles

    Science.gov (United States)

    Markley, F. Landis; Shuster, Malcolm D.

    1995-01-01

    We present a generalization of the Euler angles to axes beyond the twelve conventional sets. The generalized Euler axes must satisfy the constraint that the first and the third are orthogonal to the second; but the angle between the first and third is arbitrary, rather than being restricted to the values 0 and pi/2, as in the conventional sets. This is the broadest generalization of the Euler angles that provides a representation of an arbitrary rotation matrix. The kinematics of the generalized Euler angles and their relation to the attitude matrix are presented. As a side benefit, the equations for the generalized Euler angles are universal in that they incorporate the equations for the twelve conventional sets of Euler angles in a natural way.

  9. Timing of umbilical cord clamping and neonatal haematological status.

    Science.gov (United States)

    Jaleel, Riffat; Deeba, Farah; Khan, Ayesha

    2009-07-01

    To determine the effect of delayed umbilical cord clamping on Hb (haemoglobin) and bilirubin levels of neonates and to identify newborn babies with anaemia and refer them for treatment. This Randomized Controlled Trial was conducted in the Department of Obstetrics and Gynaecology, Unit V, Dow Medical College and Lyari General Hospital and Department of Pathology, Lyari General Hospital, between 1st November, 2006 and 15th July, 2007. Patients admitted to labour ward were selected according to inclusion criteria of the study. They were randomly allocated to 2 groups. Group A included women in whom umbilical cord was clamped immediately after birth. In Group B, clamping was delayed until cessation of pulsations in the cord. After cutting the cord, sample of blood was collected from the cut end of cord of the newborn for Hb and bilirubin. After 6 hours of birth, another sample of blood was drawn from antecubital vein for serum bilirubin. Samples were sent to laboratory for analysis. All data were entered and analyzed using SPSS version 11. Two hundred women were studied, 100 in each of the 2 groups. Mean maternal Hb was 9.75 g/dl in Group A and 9.95 g/dl in Group B. The average neonatal Hb was 14.1 g/dl in Group A and 15.2 g/dl in Group B (p = 0.008). In all 49% neonates in Group A and 37% in Group B had Hb umbilical cord clamping at birth seems to be safe and can be expected to reduce the prevalence of anaemic newborn babies in our community.

  10. Indentation metrology of clamped, ultra-thin elastic sheets

    OpenAIRE

    Vella, Dominic; Davidovitch, Benny

    2017-01-01

    We study the indentation of ultrathin elastic sheets clamped to the edge of a circular hole. This classical setup has received considerable attention lately, being used by various experimental groups as a probe to measure the surface properties and stretching modulus of thin solid films. Despite the apparent simplicity of this method, the geometric nonlinearity inherent in the mechanical response of thin solid objects renders the analysis of the resulting data a nontrivial task. Importantly, ...

  11. POLYCYTHEMIA RISK IN NEONATES WITH DELAYED CORD CLAMPING

    Directory of Open Access Journals (Sweden)

    I Gusti Agung Ayu Sri Wulandari Pramana

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Delayed Cord Clamping is still a controversial issue in the world of medicine. Until recently, the perfect times to do a Delayed Cord Clamping in various parts of the Earth in the world are still very diverse. There are a few things that became a major concern associated with Delayed Cord Clamping, one of which is the increase in blood volume due to an increase in the number of erythrocytes which led to occurrence of neonatal polycythemia which later can lead to various complications. Polycythemia in neonates is a situation where the value of venous blood hematokrit over 65% (0.65 or the amount of hemoglobin more than 22gr/Dl. However, to date the data from a variety of the latest research and analysis of the studies mention that the polycythemia that occurs in neonates with umbilical cord pinching the flush delay was mild polycythemia that can improve after 48 to 72 hours after the baby is born.

  12. Cleaning patch-clamp pipettes for immediate reuse

    Science.gov (United States)

    Kolb, I.; Stoy, W. A.; Rousseau, E. B.; Moody, O. A.; Jenkins, A.; Forest, C. R.

    2016-01-01

    Patch-clamp recording has enabled single-cell electrical, morphological and genetic studies at unparalleled resolution. Yet it remains a laborious and low-throughput technique, making it largely impractical for large-scale measurements such as cell type and connectivity characterization of neurons in the brain. Specifically, the technique is critically limited by the ubiquitous practice of manually replacing patch-clamp pipettes after each recording. To circumvent this limitation, we developed a simple, fast, and automated method for cleaning glass pipette electrodes that enables their reuse within one minute. By immersing pipette tips into Alconox, a commercially-available detergent, followed by rinsing, we were able to reuse pipettes 10 times with no degradation in signal fidelity, in experimental preparations ranging from human embryonic kidney cells to neurons in culture, slices, and in vivo. Undetectable trace amounts of Alconox remaining in the pipette after cleaning did not affect ion channel pharmacology. We demonstrate the utility of pipette cleaning by developing the first robot to perform sequential patch-clamp recordings in cell culture and in vivo without a human operator. PMID:27725751

  13. MEMS-based clamp with a passive hold function for precision position retaining of micro manipulators

    NARCIS (Netherlands)

    Brouwer, D.M.; Jong, de B.R.; Boer, de M.J.; Jansen, H.V.; Dijk, van J.; Krijnen, G.J.M.; Soemers, H.M.J.R.

    2009-01-01

    In this paper the design, modeling and fabrication of a precision MEMS-based clamp with a relatively large clamping force are presented. The purpose of the clamp is to mechanically fix a six-degree-of-freedom (DOF) MEMS-based sample manipulator (Brouwer et al J. Int. Soc. Precis. Eng. Nanotechnol. s

  14. MEMS-based clamp with a passive hold function for precision position retaining of micromanipulators

    NARCIS (Netherlands)

    Brouwer, Dannis Michel; de Jong, B.R.; de Boer, Meint J.; Jansen, Henricus V.; van Dijk, Johannes A.G.M.; van Dijk, Johannes; Krijnen, Gijsbertus J.M.; Soemers, Herman

    2009-01-01

    In this paper the design, modeling and fabrication of a precision MEMS-based clamp with arelatively large clamping force are presented. The purpose of the clamp is to mechanically fixa six-degree-of-freedom (DOF) MEMS-based sample manipulator (Brouwer et al J. Int. Soc. Precis. Eng. Nanotechnol. sub

  15. File list: Oth.ALL.10.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.10.Clamp.AllCell dm3 TFs and others Clamp All cell types SRX159170,SRX15917...2,SRX159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.ALL.10.Clamp.AllCell.bed ...

  16. File list: Oth.ALL.05.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.05.Clamp.AllCell dm3 TFs and others Clamp All cell types SRX159172,SRX15917...0,SRX159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.ALL.05.Clamp.AllCell.bed ...

  17. File list: Oth.CeL.10.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.10.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159170,SRX159172,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.10.Clamp.AllCell.bed ...

  18. File list: Oth.CeL.20.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.20.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159172,SRX159170,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.20.Clamp.AllCell.bed ...

  19. File list: Oth.ALL.50.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.Clamp.AllCell dm3 TFs and others Clamp All cell types SRX159172,SRX15917...0,SRX159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.ALL.50.Clamp.AllCell.bed ...

  20. File list: Oth.ALL.20.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.20.Clamp.AllCell dm3 TFs and others Clamp All cell types SRX159172,SRX15917...0,SRX159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.ALL.20.Clamp.AllCell.bed ...

  1. File list: Oth.CeL.05.Clamp.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.CeL.05.Clamp.AllCell dm3 TFs and others Clamp Cell line SRX159172,SRX159170,SRX...159174,SRX159166,SRX159173 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.CeL.05.Clamp.AllCell.bed ...

  2. The early effects of delayed cord clamping in term infants born to Libyan mothers

    NARCIS (Netherlands)

    Emhamed, Musbah Omar; van Rheenen, Patrick; Brabin, Bernard J

    2004-01-01

    This study was conducted to evaluate the haematological effects of the timing of umbilical cord clamping in term infants 24 h after birth in Libya. Mother-infant pairs were randomly assigned to early cord clamping (within 10s after delivery) or delayed clamping (after the cord stopped pulsating). Ma

  3. Molecular force spectroscopy with a DNA origami-based nanoscopic force clamp.

    Science.gov (United States)

    Nickels, Philipp C; Wünsch, Bettina; Holzmeister, Phil; Bae, Wooli; Kneer, Luisa M; Grohmann, Dina; Tinnefeld, Philip; Liedl, Tim

    2016-10-21

    Forces in biological systems are typically investigated at the single-molecule level with atomic force microscopy or optical and magnetic tweezers, but these techniques suffer from limited data throughput and their requirement for a physical connection to the macroscopic world. We introduce a self-assembled nanoscopic force clamp built from DNA that operates autonomously and allows massive parallelization. Single-stranded DNA sections of an origami structure acted as entropic springs and exerted controlled tension in the low piconewton range on a molecular system, whose conformational transitions were monitored by single-molecule Förster resonance energy transfer. We used the conformer switching of a Holliday junction as a benchmark and studied the TATA-binding protein-induced bending of a DNA duplex under tension. The observed suppression of bending above 10 piconewtons provides further evidence of mechanosensitivity in gene regulation.

  4. Ultra-coherent nanomechanical resonators via soft clamping and dissipation dilution

    CERN Document Server

    Tsaturyan, Yeghishe; Polzik, Eugene S; Schliesser, Albert

    2016-01-01

    The small mass and high coherence of nanomechanical resonators render them the ultimate force probe, with applications ranging from biosensing and magnetic resonance force microscopy, to quantum optomechanics. A notorious challenge in these experiments is thermomechanical noise related to dissipation through internal or external loss channels. Here, we introduce a novel approach to defining nanomechanical modes, which simultaneously provides strong spatial confinement, full isolation from the substrate, and dilution of the resonator material's intrinsic dissipation by five orders of magnitude. It is based on a phononic bandgap structure that localises the mode, without imposing the boundary conditions of a rigid clamp. The reduced curvature in the highly tensioned silicon nitride resonator enables mechanical $Q>10^{8}$ at $ 1 \\,\\mathrm{MHz}$, yielding the highest mechanical $Qf$-products ($>10^{14}\\,\\mathrm{Hz}$) yet reported at room temperature. The corresponding coherence times approach those of optically t...

  5. Glaucoma, Open-Angle

    Science.gov (United States)

    ... Programs Home > Statistics and Data > Glaucoma, Open-angle Glaucoma, Open-angle Open-angle Glaucoma Defined In open-angle glaucoma, the fluid passes ... 2010 2010 U.S. Age-Specific Prevalence Rates for Glaucoma by Age and Race/Ethnicity The prevalence of ...

  6. Investigation of the Dynamics of a Clamped-Clamped Microbeam Near the Third Mode Using a Partial Electrode

    KAUST Repository

    Masri, Karim M.

    2014-08-17

    We present an investigation of the dynamics of a clamped-clamped microbeam excited electrostatically near its third mode. To maximize the response at the third mode, a partial electrode configuration is utilized. A multi-mode Galerkin method is used to develop a reduced order model (ROM) of the beam. A shooting method to find the periodic motion is utilized to generate frequency response curves. The curves show hardenining behavior and dynamic pull-in. We show that the dynamic amplitude of the partial configuration is higher than that of a full electrode configuration. These results are promising for the use of higher-order modes for mass detection and for ultra sensitive resonant sensors.

  7. Michelson interferometer for precision angle measurement.

    Science.gov (United States)

    Ikram, M; Hussain, G

    1999-01-01

    An angle-measuring technique based on an optical interferometer is reported. The technique exploits a Michelson interferometric configuration in which a right-angle prism and a glass strip are introduced into a probe beam. Simultaneous rotation of both components along an axis results in an optical path difference between the reference and the probe beams. In a second arrangement two right-angle prisms and glass strips are introduced into two beams of a Michelson interferometer. The prisms and the strips are rotated simultaneously to introduce an optical path difference between the two beams. In our arrangement, optimization of various parameters makes the net optical path difference between the two beams approximately linear for a rotation as great as +/-20 degrees . Results are simulated that show an improvement of 2-3 orders of magnitude in error and nonlinearity compared with a previously reported technique.

  8. Size of the Optic Nerve Head and Its Relationship with the Thickness of the Macular Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer in Patients with Primary Open Angle Glaucoma

    Directory of Open Access Journals (Sweden)

    Nobuko Enomoto

    2015-01-01

    Full Text Available Purpose. To evaluate the relationships among the optic nerve head (ONH area, macular ganglion cell complex (mGCC thickness, circumpapillary retinal nerve fiber layer (cpRNFL thickness, and visual field defects in patients with primary open angle glaucoma (POAG. Methods. This retrospective study included 90 eyes of 90 patients with POAG. The ONH area, rim area, mGCC thickness, and cpRNFL thickness were measured using optical coherence tomography. Mean deviation (MD was measured using standard automated perimetry. The relationships among clinical factors including age, refraction, the ONH area, the rim area, the mGCC thickness, the cpRNFL thickness, and MD were evaluated using correlation coefficients and multiple regression analyses. Results. The significant correlation of the ONH area with refraction (r=0.362, P<0.001, the mGCC thickness (r=0.225, P=0.033, and the cpRNFL thickness (r=0.253, P=0.016 was found. Multiple regression analysis showed that the ONH area, rim area, and MD were selected as significant contributing factors to explain the mGCC thickness and cpRNFL thickness. No factor was selected to explain MD. Conclusions. The ONH area, in other words, the disc size itself may affect the mGCC thickness and cpRNFL thickness in POAG patients.

  9. Comparison of diagnostic capability of macular ganglion cell complex and retinal nerve fiber layer among primary open angle glaucoma, ocular hypertension, and normal population using Fourier-domain optical coherence tomography and determining their functional correlation in Indian population

    Directory of Open Access Journals (Sweden)

    Nabanita Barua

    2016-01-01

    Full Text Available Context: Analysis of diagnostic ability of macular ganglionic cell complex and retinal nerve fiber layer (RNFL in glaucoma. Aim: To correlate functional and structural parameters and comparing predictive value of each of the structural parameters using Fourier-domain (FD optical coherence tomography (OCT among primary open angle glaucoma (POAG and ocular hypertension (OHT versus normal population. Setting and Design: Single centric, cross-sectional study done in 234 eyes. Materials and Methods: Patients were enrolled in three groups: POAG, ocular hypertensive and normal (40 patients in each group. After comprehensive ophthalmological examination, patients underwent standard automated perimetry and FD-OCT scan in optic nerve head and ganglion cell mode. The relationship was assessed by correlating ganglion cell complex (GCC parameters with mean deviation. Results were compared with RNFL parameters. Statistical Analysis: Data were analyzed with SPSS, analysis of variance, t-test, Pearson′s coefficient, and receiver operating curve. Results: All parameters showed strong correlation with visual field (P 0.5 when compared with other parameters. None of the parameters showed significant diagnostic capability to detect OHT from normal population. In diagnosing early glaucoma from OHT and normal population, only inferior GCC had statistically significant AUC value (0.715. Conclusion: In this study, GCC and RNFL parameters showed equal predictive capability in perimetric versus normal group. In early stage, inferior GCC was the best parameter. In OHT population, single day cross-sectional imaging was not valuable.

  10. Expanding neurochemical investigations with multi-modal recording: simultaneous fast-scan cyclic voltammetry, iontophoresis, and patch clamp measurements.

    Science.gov (United States)

    Kirkpatrick, D C; McKinney, C J; Manis, P B; Wightman, R M

    2016-08-02

    Multi-modal recording describes the simultaneous collection of information across distinct domains. Compared to isolated measurements, such studies can more easily determine relationships between varieties of phenomena. This is useful for neurochemical investigations which examine cellular activity in response to changes in the local chemical environment. In this study, we demonstrate a method to perform simultaneous patch clamp measurements with fast-scan cyclic voltammetry (FSCV) using optically isolated instrumentation. A model circuit simulating concurrent measurements was used to predict the electrical interference between instruments. No significant impact was anticipated between methods, and predictions were largely confirmed experimentally. One exception was due to capacitive coupling of the FSCV potential waveform into the patch clamp amplifier. However, capacitive transients measured in whole-cell current clamp recordings were well below the level of biological signals, which allowed the activity of cells to be easily determined. Next, the activity of medium spiny neurons (MSNs) was examined in the presence of an FSCV electrode to determine how the exogenous potential impacted nearby cells. The activities of both resting and active MSNs were unaffected by the FSCV waveform. Additionally, application of an iontophoretic current, used to locally deliver drugs and other neurochemicals, did not affect neighboring cells. Finally, MSN activity was monitored during iontophoretic delivery of glutamate, an excitatory neurotransmitter. Membrane depolarization and cell firing were observed concurrently with chemical changes around the cell resulting from delivery. In all, we show how combined electrophysiological and electrochemical measurements can relate information between domains and increase the power of neurochemical investigations.

  11. Timing of umbilical cord clamping: new thoughts on an old discussion.

    Science.gov (United States)

    Arca, Gemma; Botet, Francesc; Palacio, Montse; Carbonell-Estrany, Xavier

    2010-11-01

    The optimal time to clamp the umbilical cord in preterm and full-term neonates after birth continues to be a matter of debate. A review of randomised controlled trials comparing the effects of early versus late cord clamping on maternal and infant outcomes was performed to assess data in favor of immediate or delayed clamping. Although there is no conclusive evidence, delayed cord clamping seems to be beneficial in preterm and full-term neonates without compromising the initial postpartum adaptation phase or affecting the mother in the short term. However, further randomised clinical studies are needed to confirm the benefits of delayed cord clamping.

  12. Fractal Approach in Petrology: Combining Ultra-Small Angle (USANA) and Small Angle Neutron Scattering (SANS)

    Energy Technology Data Exchange (ETDEWEB)

    LoCelso, F.; Triolo, F.; Triolo, A.; Lin, J.S.; Lucido, G.; Triolo, R.

    1999-10-14

    Ultra small angle neutron scattering instruments have recently covered the gap between the size resolution available with conventional intermediate angle neutron scattering and small angle neutron scattering instruments on one side and optical microscopy on the other side. Rocks showing fractal behavior in over two decades of momentum transfer and seven orders of magnitude of intensity are examined and fractal parameters are extracted from the combined USANS and SANS curves.

  13. Clamping stiffness and its influence on load distribution between paired internal spinal fixation devices.

    Science.gov (United States)

    Rohlmann, A; Calisse, J; Bergmann, G; Radvan, J; Mayer, H M

    1996-06-01

    The load distribution between two internal spinal fixation devices depends, besides other factors, on their stiffness. The stiffness ranges were determined experimentally for the clamps of the AO internal fixator with lateral nut and with posterior nut as well as for the clamps of the SOCON fixator. The stiffness of eight devices each differed by a factor of 3.1 for the clamp with lateral nut, by a factor of 1.5 for the clamp with posterior nut, and by a factor of 1.4 for the clamp of the SOCON fixator. For the AO clamp with lateral nut, the influence of the nut-tightening torque on the stiffness was determined. Using instrumented internal spinal fixation devices mounted to plastic vertebrae and simulating a corpectomy, the load distribution between the implants was measured for different tightening torques. It could be shown that, for the AO internal fixator whose clamps have a lateral nut, a nut-tightening torque > 5 Nm has only a negligible influence on load-sharing between the implants. Tooth damage occurs when the teeth of the clamp body and clamping jaw of the clamp with lateral nut do not gear together exactly, which leads to changes in the clamping stiffness and load-sharing between the two implants.

  14. The timing of cord clamping and oxidative stress in term newborns.

    Science.gov (United States)

    Díaz-Castro, Javier; Florido, Jesus; Kajarabille, Naroa; Garrido-Sánchez, Maria; Padilla, Carmen; de Paco, Catalina; Navarrete, Luis; Ochoa, Julio J

    2014-08-01

    Clamping and cutting of the umbilical cord is the most prevalent of all operations, but the optimal timing of cord clamping is controversial, with different timings offering advantages and disadvantages. This study, for the first time, compares the influence of early and late cord clamping in correlation with oxidative stress and inflammation signaling, Because cord clamping timing may have a significant influence on placenta-to-infant blood transfer, thereby modifying oxygenation of maternal and fetal tissues, and on the transfer of inflammatory mediators throughout the placenta. Sixty-four pregnant subjects were selected at the Gynecology and Obstetrics Services Department of the Clinico San Cecilio Hospital, Granada, Spain, based on disease-free women who experienced a normal course of pregnancy and a spontaneous, vaginal, single delivery. Half of the subjects had deliveries with early-clamped newborn infants (at 10 s), and the other half had late-clamped deliveries (at 2 min). Erythrocyte catalase activity was significantly greater in the late-clamped group than in the early-clamped group (P umbilical vein and P clamped group compared with the early-clamped group (P cord clamping, produced by an increase in antioxidant capacity and moderation of the inflammatory-mediated effects induced during delivery of term neonates. Copyright © 2014 by the American Academy of Pediatrics.

  15. Umbilical cord clamping at birth--practice in Norwegian maternity wards.

    Science.gov (United States)

    Lundberg, Camilla; Øian, Pål; Klingenberg, Claus

    2013-11-26

    The timing and practice used for umbilical cord clamping of neonates are controversial internationally as well as in Norway. We therefore wished to investigate routines and practices for umbilical cord clamping of neonates in Norway. A web-based questionnaire was sent to heads of departments of all maternity wards in Norway (n = 52). They were asked about their practice with regard to umbilical cord clamping of neonates and whether written routines had been prepared for this purpose. We defined early umbilical cord clamping as immediate or within 30 seconds and late clamping as ≥ 1 minute or not until pulsation in the umbilical cord had ceased. Fifty (96%) of the maternity institutions returned a completed questionnaire. Twelve institutions (24%) reported to clamp the umbilical cord of full-term neonates early, and 38 (76%) reported to practise late clamping. Nineteen maternity wards (38%) followed written routines for umbilical cord clamping of full-term neonates, and among these, early umbilical cord clamping was practised in nine (47%). In the 31 maternity wards that had no written routines, early umbilical cord clamping was practised in three (10%). Twenty-seven of the maternity wards reported that the child is placed on the maternal abdomen before clamping of the umbilical cord, 14 reported that the child commonly is held below the introitus before umbilical cord clamping, and the rest did not report any consistent practice. There is wide variation in the practice for umbilical cord clamping in Norwegian maternity wards, many of which have no written guidelines. We argue that national guidelines for umbilical cord clamping of neonates should be established.

  16. ß-adrenergic regulation of ion transport in pancreatic ducts: Patch-clamp study of isolated rat pancreatic ducts

    DEFF Research Database (Denmark)

    Novak, I

    1998-01-01

    much smaller effects. At comparable concentrations, it depolarized Vm by a few millivolts. Neither agonist had significant effects on intracellular Ca2+. CONCLUSIONS: This study provides the first direct evidence that adrenergic stimulation, namely, that of beta-adrenoceptors, controls ion transport....... METHODS: Small intralobular ducts were isolated from rat pancreas and studied in vitro by the whole-cell patch clamp technique. Cell membrane voltages and currents were indicators of cellular ion transport. In some ducts, intracellular Ca2+ activity was measured by fluorescence optical methods. RESULTS...... in pancreatic ducts. Similar to secretin, isoproterenol stimulation leads to opening of luminal Cl- channels, and HCO3- enters the lumen in exchange for Cl-....

  17. Clamped seismic metamaterials: ultra-low frequency stop bands

    Science.gov (United States)

    Achaoui, Y.; Antonakakis, T.; Brûlé, S.; Craster, R. V.; Enoch, S.; Guenneau, S.

    2017-06-01

    The regularity of earthquakes, their destructive power, and the nuisance of ground vibration in urban environments, all motivate designs of defence structures to lessen the impact of seismic and ground vibration waves on buildings. Low frequency waves, in the range 1-10 Hz for earthquakes and up to a few tens of Hz for vibrations generated by human activities, cause a large amount of damage, or inconvenience; depending on the geological conditions they can travel considerable distances and may match the resonant fundamental frequency of buildings. The ultimate aim of any seismic metamaterial, or any other seismic shield, is to protect over this entire range of frequencies; the long wavelengths involved, and low frequency, have meant this has been unachievable to date. Notably this is scalable and the effects also hold for smaller devices in ultrasonics. There are three approaches to obtaining shielding effects: bragg scattering, locally resonant sub-wavelength inclusions and zero-frequency stop-band media. The former two have been explored, but the latter has not and is examined here. Elastic flexural waves, applicable in the mechanical vibrations of thin elastic plates, can be designed to have a broad zero-frequency stop-band using a periodic array of very small clamped circles. Inspired by this experimental and theoretical observation, all be it in a situation far removed from seismic waves, we demonstrate that it is possible to achieve elastic surface (Rayleigh) wave reflectors at very large wavelengths in structured soils modelled as a fully elastic layer periodically clamped to bedrock. We identify zero frequency stop-bands that only exist in the limit of columns of concrete clamped at their base to the bedrock. In a realistic configuration of a sedimentary basin 15 m deep we observe a zero frequency stop-band covering a broad frequency range of 0-30 Hz.

  18. Accelerated commutation for passive clamp isolated boost converters

    OpenAIRE

    2002-01-01

    An efficient and cost effective bidirectional DC/DC converter reduces switch voltage stress via accelerated commutation allowing use of a low-cost passive clamp circuit in boost mode. The converter includes a primary circuit, transformer and secondary circuit. The primary circuit takes the form of a “full bridge converter,” a “push-pull converter,” or an “L-type converter.”. The primary circuit may include a dissipator such as a snubber circuit or small buck converter. A secondary side of the...

  19. Potassium Chloride Versus Voltage Clamp Contractures in Ventricular Muscle

    Science.gov (United States)

    Morad, M.; Reeck, S.; Rao, M.

    1981-01-01

    In frog ventricle, developed tension was markedly larger in response to depolarization caused by a voltage clamp step than to depolarization induced by high concentrations of potassium chloride. Measurement of extracellular potassium activity at the surface and at the depth of muscle during the development of contractures showed that the diffusion of potassium is much slower than the spread of depolarization through the cross section of muscle. These two observations suggest that competition between the depolarizing and the negative inotropic effects of an increase in the extracellular potassium ion concentration may determine the time course and magnitude of contractile tension in heart muscle.

  20. Effect of Clamping Rigidity of the Armour on Ballistic Performance

    Directory of Open Access Journals (Sweden)

    S. N. Dikshit

    1992-04-01

    Full Text Available Influence of the manner in which the armour plates are held during their ballistic testing on the armour performance, has been evaluated. One armour plate was clamped rigidly to the test stand while a second plate of identical composition, hardness, and dimensions was hung loosely from the target holder. Both these plates were impacted with the same type of projectiles and over the same impact velocity range. The nature of ballistic damage evaluated indicates that the manner in which the armour is held during ballistic testing has a negligible influence on its performance at least when the mass of the plate is substantially higher than that of the projectile.

  1. Euglycemic clamp insulin sensitivity and longitudinal systolic blood pressure

    DEFF Research Database (Denmark)

    Petrie, John R; Malik, Muhammad Omar; Balkau, Beverley

    2013-01-01

    Insulin resistance may be an independent risk factor for the development of hypertension, but change in blood pressure (BP) over time has not been adequately studied in healthy individuals fully characterized for insulin sensitivity. In the Relationship between Insulin Sensitivity...... and Cardiovascular disease (RISC) study, we measured insulin sensitivity (M/I) using the euglycemic clamp technique in 1073 healthy European adults (587 women, 486 men) aged 30 to 60 years followed up 3 years later. Systolic BP (SBP) at baseline was higher in insulin-resistant women (ie, those in the low sex...

  2. Pulsewidth Modulation of Neutral-Point-Clamped Indirect Matrix Converter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Poh Chiang, Loh; Gao, Feng

    2008-01-01

    discussed in the existing literature. Addressing the previously described issues, this paper focuses on the operational mode analysis of a three-level indirect matrix converter implemented using a neutral-point-clamped inversion stage and the design of a number of PWM and modulation ratio compensation...... schemes for controlling the converter with improved waveform quality. The performances and practicalities of the designed schemes are verified in simulation and experimentally using an implemented laboratory prototype with some representative results captured and presented in this paper....

  3. Contact Angle Goniometer

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  4. Delayed clamping of the umbilical cord after delivery and implications for public cord blood banking.

    Science.gov (United States)

    Allan, David S; Scrivens, Nicholas; Lawless, Tiffany; Mostert, Karen; Oppenheimer, Lawrence; Walker, Mark; Petraszko, Tanya; Elmoazzen, Heidi

    2016-03-01

    Public banking of umbilical cord blood units (CBUs) containing higher numbers of cells ensures timely engraftment after transplantation for increasing numbers of patients. Delayed clamping of the umbilical cord after birth may benefit some infants by preventing iron deficiency. Implications of delayed cord clamping for public cord blood banking remains unclear. CBUs collected by Canadian Blood Services at one collection site between November 1, 2014, and March 17, 2015, were analyzed. The delay in cord clamping after birth was timed and classified as "no delay," 20 to 60 seconds, more than 60 seconds, or more than 120 seconds. Of 367 collections, 100 reported no delay in clamping while clamping was delayed by 20 to 60 seconds (n = 69), more than 60 seconds (n = 98), or more than 120 seconds (n = 100) in the remaining cases. The mean volume and total nucleated cells (TNCs) in units with no delay in clamping were significantly greater than mean volumes for all categories of delayed clamping (Tukey's test, p clamping was delayed (p = 5.5 × 10(-8) ). The difference was most marked for cords that were clamped more than 120 seconds after delivery (6.2% compared with 39%). Delayed cord clamping greatly diminishes the volume and TNC count of units collected for a public cord blood bank. Creating an inventory of CBUs with high TNC content may take more time than expected. © 2015 AABB.

  5. Delayed Umbilical Cord Clamping in the 21st Century: Indications for Practice.

    Science.gov (United States)

    Bayer, Kimberly

    2016-02-01

    Health care providers have debated the timing of umbilical cord clamping since the days of Aristotle. Delayed cord clamping was the mainstay of practice until about the 1950s when it was changed to immediate clamping on the basis of a series of blood volume studies combined with the introduction of active management of the third stage of labor. However, in recent years, several systematic reviews advise that delayed cord clamping should be used in all births for at least 30 to 60 seconds. The purpose of this article is to discuss the physiology of umbilical cord clamping, the potential benefits and adverse effects of delayed cord clamping, and how this affects the advanced practice nurse. A search of PubMed, Cochrane Reviews, and Clinical Key was used to find relevant research on the topic of umbilical cord clamping. Potential benefits of delayed cord clamping include decreased frequency of iron-deficiency anemia in the first year of life with improved neurodevelopmental outcomes in term infants, reduced need for blood transfusions, possible autologous transfusion of stem cells, and a decreased incidence of intraventricular hemorrhage. Apprehension exists regarding the feasibility of the practice as well as the potential hindrance of immediate resuscitation. There is a need to begin to look for populations for which delayed cord clamping can be implemented. Recommendations are inconsistent on the patient population and timing; therefore, further studies are needed to understand the multiple variables that affect timing of umbilical cord clamping.

  6. Randomised trial of cord clamping and initial stabilisation at very preterm birth.

    Science.gov (United States)

    Duley, Lelia; Dorling, Jon; Pushpa-Rajah, Angela; Oddie, Sam J; Yoxall, Charles William; Schoonakker, Bernard; Bradshaw, Lucy; Mitchell, Eleanor J; Fawke, Joe Anthony

    2017-09-18

    For very preterm births, to compare alternative policies for umbilical cord clamping and immediate neonatal care. Parallel group randomised (1:1) trial, using sealed opaque numbered envelopes. Eight UK tertiary maternity units. 261 women expected to have a live birth before 32 weeks, and their 276 babies. Cord clamping after at least 2 min and immediate neonatal care with cord intact, or clamping within 20 s and immediate neonatal care after clamping. Intraventricular haemorrhage (IVH), death before discharge. 132 women (137 babies) were allocated clamping ≥2 min and neonatal care cord intact, and 129 (139) clamping ≤20 s and neonatal care after clamping; six mother-infant dyads were excluded (2, 4) as birth was after 35(+6) weeks, one withdrew (death data only available) (0, 1). Median gestation was 28.9 weeks for those allocated clamping ≥2 min, and 29.2 for those allocated clamping ≤20 s. Median time to clamping was 120 and 11 s, respectively. 7 of 135 infants (5.2%) allocated clamping ≥2 min died and 15 of 135 (11.1%) allocated clamping ≤20 s; risk difference (RD) -5.9% (95% CI -12.4% to 0.6%). Of live births, 43 of 134 (32%) had IVH vs 47 of 132 (36%), respectively; RD -3.5% (-14.9% to 7.8%). There were no clear differences in other outcomes for infants or mothers. This is promising evidence that clamping after at least 2 min and immediate neonatal care with cord intact at very preterm birth may improve outcome; a large trial is urgently needed. ISRCTN 21456601. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Patch-clamp detection of macromolecular translocation along nuclear pores

    Directory of Open Access Journals (Sweden)

    Bustamante J.O.

    1998-01-01

    Full Text Available The present paper reviews the application of patch-clamp principles to the detection and measurement of macromolecular translocation along the nuclear pores. We demonstrate that the tight-seal 'gigaseal' between the pipette tip and the nuclear membrane is possible in the presence of fully operational nuclear pores. We show that the ability to form a gigaseal in nucleus-attached configurations does not mean that only the activity of channels from the outer membrane of the nuclear envelope can be detected. Instead, we show that, in the presence of fully operational nuclear pores, it is likely that the large-conductance ion channel activity recorded derives from the nuclear pores. We conclude the technical section with the suggestion that the best way to demonstrate that the nuclear pores are responsible for ion channel activity is by showing with fluorescence microscopy the nuclear translocation of ions and small molecules and the exclusion of the same from the cisterna enclosed by the two membranes of the envelope. Since transcription factors and mRNAs, two major groups of nuclear macromolecules, use nuclear pores to enter and exit the nucleus and play essential roles in the control of gene activity and expression, this review should be useful to cell and molecular biologists interested in understanding how patch-clamp can be used to quantitate the translocation of such macromolecules into and out of the nucleus

  8. Optical power equalization using Fabry-Perot semiconductor optical amplifier

    Institute of Scientific and Technical Information of China (English)

    Yun Ling; Kun Qiu; Wei Zhang; Ying Pang

    2006-01-01

    A novel scheme of optical power equalization based on Fabry-Perot semiconductor optical amplifier (FPSOA) is proposed. Because of the gain characteristic of FP-SOA, real-time controlling mechanism according to input optical power is aborted in the scheme. The simulations show that 10-dB pulse peak power variation can be clamped in less than i dB. The influences of injecting current, pulse periods, and pulse width are discussed.

  9. The Function of the Magnetic-Optic Modulation in the Very Small Rotatory Angle of Polarization%磁光调制技术在光偏振微小旋转角精密测量中的应用

    Institute of Scientific and Technical Information of China (English)

    钱小陵; 常悦

    2001-01-01

    An experimental device is introduced which improves themeasurement accuracy of polarimetry very small rotatory angle of polarization to the magnitude of 10-4 degree by applying the magnetic-optic modulation. The working principles of the device is described in details and the data obtained from the experiment is also provided%提供了一种实验装置,在光偏振微小旋转角的测量中,应用磁光调制技术,对薄膜样品的克尔效应、药物原料的旋光效应和化学试剂的费尔德常数进行了观测、测量.其中在费尔德常数的测量中,精度达到了亚毫度的数量级.详细介绍了该装置的工作原理,以及在实验中获得的数据.

  10. Grazing incidence angle based sensing approach integrated with fiber-optic Fourier transform infrared (FO-FTIR) spectroscopy for remote and label-free detection of medical device contaminations

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Moinuddin, E-mail: moinuddin.hassan@fda.hhs.gov; Ilev, Ilko [Optical Therapeutics and Medical Nanophotonics Laboratory, Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993 (United States)

    2014-10-15

    Contamination of medical devices has become a critical and prevalent public health safety concern since medical devices are being increasingly used in clinical practices for diagnostics, therapeutics and medical implants. The development of effective sensing methods for real-time detection of pathogenic contamination is needed to prevent and reduce the spread of infections to patients and the healthcare community. In this study, a hollow-core fiber-optic Fourier transform infrared spectroscopy methodology employing a grazing incidence angle based sensing approach (FO-FTIR-GIA) was developed for detection of various biochemical contaminants on medical device surfaces. We demonstrated the sensitivity of FO-FTIR-GIA sensing approach for non-contact and label-free detection of contaminants such as lipopolysaccharide from various surface materials relevant to medical device. The proposed sensing system can detect at a minimum loading concentration of approximately 0.7 μg/cm{sup 2}. The FO-FTIR-GIA has the potential for the detection of unwanted pathogen in real time.

  11. Combining single-molecule optical trapping and small-angle x-ray scattering measurements to compute the persistence length of a protein ER/K alpha-helix.

    Science.gov (United States)

    Sivaramakrishnan, S; Sung, J; Ali, M; Doniach, S; Flyvbjerg, H; Spudich, J A

    2009-12-02

    A relatively unknown protein structure motif forms stable isolated single alpha-helices, termed ER/K alpha-helices, in a wide variety of proteins and has been shown to be essential for the function of some molecular motors. The flexibility of the ER/K alpha-helix determines whether it behaves as a force transducer, rigid spacer, or flexible linker in proteins. In this study, we quantify this flexibility in terms of persistence length, namely the length scale over which it is rigid. We use single-molecule optical trapping and small-angle x-ray scattering, combined with Monte Carlo simulations to demonstrate that the Kelch ER/K alpha-helix behaves as a wormlike chain with a persistence length of approximately 15 nm or approximately 28 turns of alpha-helix. The ER/K alpha-helix length in proteins varies from 3 to 60 nm, with a median length of approximately 5 nm. Knowledge of its persistence length enables us to define its function as a rigid spacer in a translation initiation factor, as a force transducer in the mechanoenzyme myosin VI, and as a flexible spacer in the Kelch-motif-containing protein.

  12. Combining Single-Molecule Optical Trapping and Small-Angle X-Ray Scattering Measurements to Compute the Persistence Length of a Protein ER/K alpha-Helix

    DEFF Research Database (Denmark)

    Sivaramakrishnan, S.; Sung, J.; Ali, M.

    2009-01-01

    A relatively unknown protein structure motif forms stable isolated single alpha-helices, termed ER/K alpha-helices, in a wide variety of proteins and has been shown to be essential for the function of some molecular motors. The flexibility of the ER/K alpha-helix determines whether it behaves...... as a force transducer, rigid spacer, or flexible linker in proteins. In this study, we quantity this flexibility in terms of persistence length, namely the length scale over which it is rigid. We use single-molecule optical trapping and small-angle x-ray scattering, combined with Monte Carlo simulations...... to demonstrate that the Kelch ER/K alpha-helix behaves as a wormlike chain with a persistence length of similar to 15 nm or similar to 28 turns of alpha-helix. The ER/K alpha-helix length in proteins varies from 3 to 60 nm, with a median length of similar to 5 nm. Knowledge of its persistence length enables us...

  13. Optimal timing of umbilical cord clamping for term and preterm babies.

    Science.gov (United States)

    Duley, Lelia; Batey, Natalie

    2013-11-01

    Deferring cord clamping allows blood flow between baby and placenta to continue for a few moments. This often leads to increased neonatal blood volume at birth. It also allows for longer transition to the neonatal circulation. Optimal timing for clamping the cord remains uncertain. This paper discusses the physiology of placental transfusion and presents the evidence from systematic reviews of randomised trials comparing alternative strategies for cord clamping for both term and preterm births. For healthy term infants, deferring cord clamping increases iron stores in infancy. Therefore, a more liberal approach to deferring cord clamping appears to be warranted, provided screening and treatment for jaundice requiring phototherapy is available. For preterm births, although there are few data on the main clinical outcomes, the evidence is promising that deferred cord clamping may be beneficial. For both term and preterm infants there is little information about long term development. © 2013.

  14. Application of Numerical Simulation for the Verification of Design of Clamping a Workpiece in Jaws

    Science.gov (United States)

    Oravcová, Jarmila; Riečičiarová, Eva

    2016-12-01

    This paper deals with the use of the numerical computer oriented method for the analysis and verification of the design of workpiece clamping. The inaccuracies of the positioning in clamping locating points were simulated using the FEM software ANSYS. The influence of inaccuracies in the positions of contact locating points on the displacements of the workpiece characteristic points and their position in clamped removable jaws was examined. The reaction forces in the contact locating points were also computed and analyzed.

  15. Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs.

    Science.gov (United States)

    Bhatt, Sasmira; Alison, Beth J; Wallace, Euan M; Crossley, Kelly J; Gill, Andrew W; Kluckow, Martin; te Pas, Arjan B; Morley, Colin J; Polglase, Graeme R; Hooper, Stuart B

    2013-04-15

    Delayed cord clamping improves circulatory stability in preterm infants at birth, but the underlying physiology is unclear. We investigated the effects of umbilical cord clamping, before and after ventilation onset, on cardiovascular function at birth. Prenatal surgery was performed on lambs (123 days) to implant catheters into the pulmonary and carotid arteries and probes to measure pulmonary (PBF), carotid (CaBF) and ductus arteriosus blood flows. Lambs were delivered at 126 ± 1 days and: (1) the umbilical cord was clamped at delivery and ventilation was delayed for about 2 min (Clamp 1st; n = 6), and (2) umbilical cord clamping was delayed for 3-4 min, until after ventilation was established (Vent 1st; n = 6). All lambs were subsequently ventilated for 30 min. In Clamp 1st lambs, cord clamping rapidly (within four heartbeats), but transiently, increased pulmonary and carotid arterial pressures (by ∼30%) and CaBF (from 30.2 ± 5.6 to 40.1 ± 4.6 ml min(-1) kg(-1)), which then decreased again within 30-60 s. Following ventilation onset, these parameters rapidly increased again. In Clamp 1st lambs, cord clamping reduced heart rate (by ∼40%) and right ventricular output (RVO; from 114.6 ± 14.4 to 38.8 ± 9.7 ml min(-1) kg(-1)), which were restored by ventilation. In Vent 1st lambs, cord clamping reduced RVO from 153.5 ± 3.8 to 119.2 ± 10.6 ml min(-1) kg(-1), did not affect heart rates and resulted in stable blood flows and pressures during transition. Delaying cord clamping for 3-4 min until after ventilation is established improves cardiovascular function by increasing pulmonary blood flow before the cord is clamped. As a result, cardiac output remains stable, leading to a smoother cardiovascular transition throughout the early newborn period.

  16. Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs

    Science.gov (United States)

    Bhatt, Sasmira; Alison, Beth J; Wallace, Euan M; Crossley, Kelly J; Gill, Andrew W; Kluckow, Martin; te Pas, Arjan B; Morley, Colin J; Polglase, Graeme R; Hooper, Stuart B

    2013-01-01

    Delayed cord clamping improves circulatory stability in preterm infants at birth, but the underlying physiology is unclear. We investigated the effects of umbilical cord clamping, before and after ventilation onset, on cardiovascular function at birth. Prenatal surgery was performed on lambs (123 days) to implant catheters into the pulmonary and carotid arteries and probes to measure pulmonary (PBF), carotid (CaBF) and ductus arteriosus blood flows. Lambs were delivered at 126 ± 1 days and: (1) the umbilical cord was clamped at delivery and ventilation was delayed for about 2 min (Clamp 1st; n = 6), and (2) umbilical cord clamping was delayed for 3–4 min, until after ventilation was established (Vent 1st; n = 6). All lambs were subsequently ventilated for 30 min. In Clamp 1st lambs, cord clamping rapidly (within four heartbeats), but transiently, increased pulmonary and carotid arterial pressures (by ∼30%) and CaBF (from 30.2 ± 5.6 to 40.1 ± 4.6 ml min−1 kg−1), which then decreased again within 30–60 s. Following ventilation onset, these parameters rapidly increased again. In Clamp 1st lambs, cord clamping reduced heart rate (by ∼40%) and right ventricular output (RVO; from 114.6 ± 14.4 to 38.8 ± 9.7 ml min−1 kg−1), which were restored by ventilation. In Vent 1st lambs, cord clamping reduced RVO from 153.5 ± 3.8 to 119.2 ± 10.6 ml min−1 kg−1, did not affect heart rates and resulted in stable blood flows and pressures during transition. Delaying cord clamping for 3–4 min until after ventilation is established improves cardiovascular function by increasing pulmonary blood flow before the cord is clamped. As a result, cardiac output remains stable, leading to a smoother cardiovascular transition throughout the early newborn period. PMID:23401615

  17. Diuretic response to acute hypertension is blunted during angiotensin II clamp

    DEFF Research Database (Denmark)

    Leong, Patrick K K; Zhang, Yibin; Yang, Li E;

    2002-01-01

    ("ANG II clamp"). When blood pressure was acutely increased 50-60 mmHg by arterial constriction without ANG II clamp, urine output and endogenous lithium clearance increased 4.0- and 6.7-fold, respectively. With ANG II clamp, the effects of acute hypertension were reduced 50%: urine output...... and endogenous lithium clearance increased two- and threefold, respectively. We conclude that HOE-140, an inhibitor of the B(2) receptor, potentiates the sensitivity of arterial pressure to ANG II and that clamping systemic ANG II levels during acute hypertension blunts the magnitude of the pressure diuretic...

  18. Modeling of SVM Diode Clamping Three-Level Inverter Connected to Grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    PLECS is used to model the diode clamping three-level inverter connected to grid and good results are obtained. First the output voltage SVM is described for diode clamping three-level inverter with loads connected to Y. Then the output voltage SVM of diode clamping three-level inverter is simply...... is very powerful tool to real power circuits and it is very easy to simulate them. They have also verified that SVM control strategy is feasible to control the diode clamping three-level inverter....

  19. Electrically integrated SU-8 clamped graphene drum resonators for strain engineering

    Science.gov (United States)

    Lee, Sunwoo; Chen, Changyao; Deshpande, Vikram V.; Lee, Gwan-Hyoung; Lee, Ilkyu; Lekas, Michael; Gondarenko, Alexander; Yu, Young-Jun; Shepard, Kenneth; Kim, Philip; Hone, James

    2013-04-01

    Graphene mechanical resonators are the ultimate two-dimensional nanoelectromechanical systems (NEMS) with applications in sensing and signal processing. While initial devices have shown promising results, an ideal graphene NEMS resonator should be strain engineered, clamped at the edge without trapping gas underneath, and electrically integratable. In this Letter, we demonstrate fabrication and direct electrical measurement of circular SU-8 polymer-clamped chemical vapor deposition graphene drum resonators. The clamping increases device yield and responsivity, while providing a cleaner resonance spectrum from eliminated edge modes. Furthermore, the clamping induces a large strain in the resonator, increasing its resonant frequency.

  20. COMPARISON OF EARLY AND DELAYED UMBILICAL CORD CLAMPING IN THE THIRD STAGE OF LABOUR

    Directory of Open Access Journals (Sweden)

    Tamara Serdinšek

    2015-09-01

    Full Text Available Background: Umbilical cord clamping in the third stage of labour is still controversial. Early cord clamping is defined as clamping at 10, 15, 30 or 60 seconds after delivery and delayed as clamping after 60 seconds or at 2-5 minutes after delivery, when the cord stops pulsating or when the placenta is visible within the birth canal. Early clamping is one of the three components of active management of the third stage of labour, which has been used widely in modern obstetrics during the last century. However, in some northern European countries, various parts of the USA and Canada and in developing countries physiological management is preferred.Conclusions: After publication of several trials describing advantages of delayed clamping, this has recently been progressively replacing early clamping. The most important advantages of delayed cord clamping are higher haemoglobin and ferritin levels, higher iron stores, lower incidence of iron deficiency anaemia, better cardiopulmonary adaptation, lower rate of respiratory distress syndrome, and longer duration of early breastfeeding in term neonates, while there is no increase in the incidence of postpartum haemorrhage. Delayed clamping seems to bring some advantages for preterm neonates as well. However, caution is still advised because of the potential adverse effects, especially polycythaemia with hyperviscosity, hyperbilirubinaemia and respiratory distress.

  1. Beliefs and practices of obstetric care providers regarding umbilical cord clamping.

    Science.gov (United States)

    Hill, Allyson L; Fontenot, Holly B

    2014-01-01

    The optimal timing for umbilical cord clamping after birth has yet to be established, and controversy exists. There is evidence of potentially significant health benefits of delayed cord clamping for both full-term and preterm newborns, but this practice has not been widely adopted. This column takes a second look at two recent studies in which researchers examined the beliefs and practices of obstetric care providers regarding umbilical cord clamping in North America. Nurses who are aware of the latest science and who understand both existing practice patterns as well as practice barriers to delayed clamping can be leaders in and advocates for change. © 2014 AWHONN.

  2. Cryogenic Clamp-on Ultrasonic Flowmeters using Single Crystal Piezoelectric Transducers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Clamp-on ultrasound cryogenic flowmeters using single crystal piezoelectric transducers are proposed to enable reliable, accurate cryogenic instrumentation needs in...

  3. Mechanism of ATP-driven PCNA clamp loading by S. cerevisiae RFC.

    Science.gov (United States)

    Chen, Siying; Levin, Mikhail K; Sakato, Miho; Zhou, Yayan; Hingorani, Manju M

    2009-05-08

    Circular clamps tether polymerases to DNA, serving as essential processivity factors in genome replication, and function in other critical cellular processes as well. Clamp loaders catalyze clamp assembly onto DNA, and the question of how these proteins construct a topological link between a clamp and DNA, especially the mechanism by which ATP is utilized for the task, remains open. Here we describe pre-steady-state analysis of ATP hydrolysis, proliferating cell nuclear antigen (PCNA) clamp opening, and DNA binding by Saccharomyces cerevisiae replication factor C (RFC), and present the first kinetic model of a eukaryotic clamp-loading reaction validated by global data analysis. ATP binding to multiple RFC subunits initiates a slow conformational change in the clamp loader, enabling it to bind and open PCNA and to bind DNA as well. PCNA opening locks RFC into an active state, and the resulting RFC.ATP.PCNA((open)) intermediate is ready for the entry of DNA into the clamp. DNA binding commits RFC to ATP hydrolysis, which is followed by PCNA closure and PCNA.DNA release. This model enables quantitative understanding of the multistep mechanism of a eukaryotic clamp loader and furthermore facilitates comparative analysis of loaders from diverse organisms.

  4. Study of Dynamic Behavior of Multilayered Clamped Composite Skewed Hypar Shell Roofs under Impact Load

    Directory of Open Access Journals (Sweden)

    Sanjoy Das Neogi

    2013-01-01

    Full Text Available With advancement in the field of structural engineering, hunt for smarter materials has channelised the research towards the application of composite material. It is the high specific weight and specific stiffness of this material that have drawn the interest of different industrial sectors. Civil engineers also picked up composites to use it as a roofing material. Laminated composite shells, which can cover large column-free area and reduces dead weight of structure, show vulnerability under sudden impact due to their low transverse shear resistances. This study utilises finite element tool to investigate the dynamic response of a multilayered laminated composite hypar shells for fully clamped boundary condition. This class of shells is unique in a sense that the curvature has only the radius of cross curvature and these shells do not admit easy closed form solution particularly when the boundary conditions are complicated. Contact behavior of impactor and impacted mass has been modeled by modified Hertzian contact law and time-dependent equations are solved using Newmark’s time integration technique. Basic aim is to analyse the shell for symmetrically placed multilayered angle and cross ply lamination under different impact velocities.

  5. Variable angle transmittance of silver grid transparent electrodes

    Science.gov (United States)

    Zhao, Yuan-Yuan; Zheng, Mei-Ling; Dong, Xian-Zi; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2016-10-01

    We focus on investigating the optical transmittance of silver grid transparent electrodes (SGTEs) in variable angle view theoretically and experimentally, rather than the optical transmittance under the normal incidence. The variable angle transmittance (VAT) values of SGTEs are measured on a home-made experimental setup. The experimental results about difference of the transmittance difference under different angles are small and negligible, although the measured angle is changed. Theoretically, the physical mechanism on nearly constant transmittance for different angle view can be well explained according to the theory of geometrical optics. This study provides an approach for investigating the VAT values of SGTEs in a controllable fashion and the influence of viewing angle of the touch screen.

  6. Electrothermally actuated tunable clamped-guided resonant microbeams

    KAUST Repository

    Alcheikh, Nouha

    2017-06-11

    We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide–range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

  7. Trans-Z-source Neutral Point Clamped inverter

    DEFF Research Database (Denmark)

    Mo, W.; Loh, P. C.; Li, D.;

    2012-01-01

    Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...

  8. The timing of umbilical cord clamping at birth: physiological considerations.

    Science.gov (United States)

    Hooper, Stuart B; Binder-Heschl, Corinna; Polglase, Graeme R; Gill, Andrew W; Kluckow, Martin; Wallace, Euan M; Blank, Douglas; Te Pas, Arjan B

    2016-01-01

    While it is now recognized that umbilical cord clamping (UCC) at birth is not necessarily an innocuous act, there is still much confusion concerning the potential benefits and harms of this common procedure. It is most commonly assumed that delaying UCC will automatically result in a time-dependent net placental-to-infant blood transfusion, irrespective of the infant's physiological state. Whether or not this occurs, will likely depend on the infant's physiological state and not on the amount of time that has elapsed between birth and umbilical cord clamping (UCC). However, we believe that this is an overly simplistic view of what can occur during delayed UCC and ignores the benefits associated with maintaining the infant's venous return and cardiac output during transition. Recent experimental evidence and observations in humans have provided compelling evidence to demonstrate that time is not a major factor influencing placental-to-infant blood transfusion after birth. Indeed, there are many factors that influence blood flow in the umbilical vessels after birth, which depending on the dominating factors could potentially result in infant-to-placental blood transfusion. The most dominant factors that influence umbilical artery and venous blood flows after birth are lung aeration, spontaneous inspirations, crying and uterine contractions. It is still not entirely clear whether gravity differentially alters umbilical artery and venous flows, although the available data suggests that its influence, if present, is minimal. While there is much support for delaying UCC at birth, much of the debate has focused on a time-based approach, which we believe is misguided. While a time-based approach is much easier and convenient for the caregiver, ignoring the infant's physiology during delayed UCC can potentially be counter-productive for the infant.

  9. Scleral spur visibility of anterior chamber angle measured by Fourier optic coherence tomography%傅立叶光学相干断层扫描检测眼房角巩膜突可见性分析

    Institute of Scientific and Technical Information of China (English)

    张海涛; 徐英英; 王保君; 朱红军

    2011-01-01

    Objective To assess visibility of scleral spur in images of anterior chamber angle measured by the CAM model of Fourier optic coherence tomography (OCT). Methods Subjects aged 40 years or older were selected from outpatients in our opthalmologic clinic. All participants underwent standard ocular examinations, and anterior chamber angle was measured by CAM-L model of RTVue-OCT (Optovue Inc,USA) and gonioscopy. Visibility of scleral spur in OCT images and its related factor were analyzed. Results 98 subjects (98 eyes) aged (63.3±10.5)y included 62 females (63.3%) were selected in this study. There were 286 in 392 quadrants (73.0%) with visualized scleral spur, which had significant difference among local bulbar conjunctiva thickened or not (P<0.01). Logistic multiple regression showed that the visibility of scleral spur was not associated with gender, age, gonioscope grades (P>0.05), but significant associated with local bulbar conjunctiva thickened (OR=0.113, P<0.01) and quadrants (OR of superior/temporal=0.210, OR of inferior/temporal=0.340, P<0.01), of which there were different scleral spur visibility in superior and inferior quadrants compared with temporal(OR=0.210, 0.340, P<0.01). Angle status was still identified in 80.2% quadrants on condition that scleral spur was not visualized. Conclusions Fourier optic coherence tomography has good feasibility to detect anterior chamber angle as an alternative method, and may supply helpful information to estimate the pathogenesis of angle closure glaucoma.%目的 探讨傅立叶光学相干断层扫描仪CAM模块房角测量图像中巩膜突可见性及其影响因素.方法 连续选择本院眼科门诊40岁及以上患者,所有受试者均接受眼科常规项目检查,房角均分别接受Rtvue OCT(Optovue Inc,USA)CAM模块和房角镜检查.分析OCT图像中巩膜突的可见性及其影响因素.结果 受试者共98例(98眼),年龄(63.3±10.5)岁,其中女性62例(63.3%).在392

  10. 眼前节相干光断层扫描在原发性闭角型青光眼诊治中的应用%Anterior segment optical coherence tomography for the evaluation of primary angle closure glaucoma

    Institute of Scientific and Technical Information of China (English)

    刘杏; 李媚

    2013-01-01

    眼前节相干光断层扫描(AS-OCT)是继超声生物显微镜(UBM)后又一种眼前段成像检测手段,其为无创性、非接触性,分辨率较UBM高.可测量包括角膜、前房、前房角、虹膜、晶状体等多个眼前段结构参数.本文评价了AS-OCT在原发性闭角型青光眼(PACG)诊治中利用AS-OCT了解PACG和正常人眼前段生物学参数的差异,了解周边虹膜切开(或切除)术后、小梁切除术后、白内障手术后PACG的眼前段结构性参数的变化,以及对小梁切除术后滤过泡功能进行评估等,强调AS-OCT在PACG的诊断、发病机制、治疗观察中具有重要的临床应用价值.%Anterior segment optical coherence tomography (AS-OCT) is an imaging instrument developped after ultrasound biomi-croscopy (UBM). Moreover, AS-OCT is a non-invasive and non-contact instrument with a higher resolution than UBM. AS-OCT offers anterior segment images of the cornea, anterior chamber, anterior chamber angle, iris and lens. In this article, the value of AS-OCT is e-valuated in the diagnosis and treatment of primary angle closure glaucoma (PACG), including the application of AS-OCT in observing the differences between PACG and normal controls, the changes in anterior segment configuration after peripheral iridectomy/trabeculec-tomy/ cataract surgery in PACG, and the morphology of filtering blebs after trabeculectomy. The present study showed that AS-OCT would play an important role in the diagnosis, treatment choice and pathogenesis study of PACG.

  11. Common genetic variants associated with open-angle glaucoma

    NARCIS (Netherlands)

    Ramdas, Wishal D.; van Koolwijk, Leonieke M. E.; Lemij, Hans G.; Pasutto, Francesca; Cree, Angela J.; Thorleifsson, Gudmar; Janssen, Sarah F.; Jacoline, Ten Brink; Amin, Najaf; Rivadeneira, Fernando; Wolfs, Roger C. W.; Walters, G. Bragi; Jonasson, Fridbert; Weisschuh, Nicole; Mardin, Christian Y.; Gibson, Jane; Zegers, Richard H. C.; Hofman, Albert; de Jong, Paulus T. V. M.; Uitterlinden, Andre G.; Oostra, Ben A.; Thorsteinsdottir, Unnur; Gramer, Eugen; Welgen-Luessen, Ulrich C.; Kirwan, James F.; Bergen, Arthur A. B.; Reis, Andre; Stefansson, Kari; Lotery, Andrew J.; Vingerling, Johannes R.; Jansonius, Nomdo M.; Klaver, Caroline C. W.; van Duijn, Cornelia M.

    2011-01-01

    Open-angle glaucoma (glaucoma) is a major eye disorder characterized by optic disc pathology. Recent genome-wide association studies identified new loci associated with clinically relevant optic disc parameters, such as the optic disc area and vertical cup-disc ratio (VCDR). We examined to what exte

  12. Creation of a multi-reference-angle comparator

    Science.gov (United States)

    Bručas, Domantas; Giniotis, Vytautas

    2009-03-01

    Many geodetic and industrial instruments utilize precise angle determination. Metrological calibration and testing of such devices is very complicated, due to the large number of angular position values generated, and often cannot be accomplished using classical means of angle determination. Therefore a special comparator (test rig) capable of calibration geodetic and other angle-measuring instruments and implementing multiple references for angle determination has been created. Several modernized optical devices were used on the test rig, together with the implementation of a special calibration method. In this paper the construction of the rig, modernization of the optical devices, calibration, and some results of measurements are presented.

  13. Current umbilical cord clamping practices and attitudes of obstetricians and midwives toward delayed cord clamping in Saudi Arabia.

    Science.gov (United States)

    Ibrahim, Nadia O; Sukkarieh, Hatouf H; Bustami, Rami T; Alshammari, Elaf A; Alasmari, Lama Y; Al-Kadri, Hanan M

    2017-01-01

    In Saudi Arabia, as in many countries, there is usually no clear definition of the timing of umbilical cord clamping (UCC) in the policies and procedures used by hospitals. The World Health Organization (WHO) recommends delayed cord clamping (DCC) ( > 1 minute after birth) as it can significantly improve hemodynamics and long-term neurodevelopment. To investigate current practices of healthcare professionals on the timing of UCC in Saudi Arabia. Cross-sectional survey. Five tertiary hospitals in Riyadh, Saudi Arabia, during May to October 2016. Obstetricians and midwives completed a widely-used questionnaire on UCC practices. Current UCC practices and attitudes of obstetricians and midwives toward DCC. Eighty-two obstetricians and 75 midwives completed the questionnaire for a response rate of 80%. The majority of respondents were aged 30 years or older (81%) and 84% were females. Most respondents were non-Saudi (66%) and had an educational level of bachelor's degree or higher (72%). Only 42% of respondents reported the existence of UCC guidelines in their practice; 38% reported the existence of a set time for UCC when the neonate was term and healthy, and only 32% had a set time for UCC in preterm neonates. While lower levels of agreement were reported among obstetricians and midwives on the benefits of DCC for babies requiring positive pressure ventilation, the majority of respondents (69-71%) thought that DCC was generally good for both term and preterm babies and that its benefits extend beyond the neonatal period. While the majority of obstetricians and midwives that participated in this study had a positive perception toward DCC, this did not translate to their daily practice as most of these professionals reported a lack of existing UCC guidelines in their institutions. Further studies are warranted to confirm these findings. Participant selection by convenience sampling.

  14. Reading Angles in Maps

    Science.gov (United States)

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  15. Molecular mechanisms underlying primary open angle glaucoma

    NARCIS (Netherlands)

    Janssen, S.F.

    2014-01-01

    Primary open angle glaucoma (POAG) is a complex, multigenetic and heterogeneous optic neuropathy. It is an insidious disease that untreated leads to irreversible visual field loss and blindness. Worldwide, glaucoma causes around 12% of blindness. Although various risk factors have been established,

  16. Structural insight into β-Clamp and its interaction with DNA Ligase in Helicobacter pylori.

    Science.gov (United States)

    Pandey, Preeti; Tarique, Khaja Faisal; Mazumder, Mohit; Rehman, Syed Arif Abdul; Kumari, Nilima; Gourinath, Samudrala

    2016-08-08

    Helicobacter pylori, a gram-negative and microaerophilic bacterium, is the major cause of chronic gastritis, gastric ulcers and gastric cancer. Owing to its central role, DNA replication machinery has emerged as a prime target for the development of antimicrobial drugs. Here, we report 2Å structure of β-clamp from H. pylori (Hpβ-clamp), which is one of the critical components of DNA polymerase III. Despite of similarity in the overall fold of eubacterial β-clamp structures, some distinct features in DNA interacting loops exists that have not been reported previously. The in silico prediction identified the potential binders of β-clamp such as alpha subunit of DNA pol III and DNA ligase with identification of β-clamp binding regions in them and validated by SPR studies. Hpβ-clamp interacts with DNA ligase in micromolar binding affinity. Moreover, we have successfully determined the co-crystal structure of β-clamp with peptide from DNA ligase (not reported earlier in prokaryotes) revealing the region from ligase that interacts with β-clamp.

  17. The transducer domain is important for clamp operation in human DNA topoisomerase IIalpha

    DEFF Research Database (Denmark)

    Oestergaard, Vibe H; Bjergbaek, Lotte; Skouboe, Camilla

    2003-01-01

    the clamp to the enzyme core. Although structurally conserved, it is unclear whether the transducer domain is involved in clamp mechanism. We have purified and characterized a human topoisomerase II alpha enzyme with a two-amino acid insertion at position 408 in the transducer domain. The enzyme retains...

  18. Angiotensin II clamp prevents the second step in renal apical NHE3 internalization during acute hypertension

    DEFF Research Database (Denmark)

    Leong, Patrick K K; Yang, Li E; McDonough, Alicia A

    2002-01-01

    . Plasma ANG II concentration of anesthesized Sprague-Dawley rats was clamped by simultaneous infusion of the ANG I-converting enzyme inhibitor captopril (12 microg/min) and ANG II (20 ng. kg(-1). min(-1)). Blood pressure was increased 50 mmHg for 20 min by arterial constriction +/- ANG II clamp or by sham...

  19. Implementing dynamic clamp with synaptic and artificial conductances in mouse retinal ganglion cells.

    Science.gov (United States)

    Huang, Jin Y; Stiefel, Klaus M; Protti, Dario A

    2013-05-16

    Ganglion cells are the output neurons of the retina and their activity reflects the integration of multiple synaptic inputs arising from specific neural circuits. Patch clamp techniques, in voltage clamp and current clamp configurations, are commonly used to study the physiological properties of neurons and to characterize their synaptic inputs. Although the application of these techniques is highly informative, they pose various limitations. For example, it is difficult to quantify how the precise interactions of excitatory and inhibitory inputs determine response output. To address this issue, we used a modified current clamp technique, dynamic clamp, also called conductance clamp (1, 2, 3) and examined the impact of excitatory and inhibitory synaptic inputs on neuronal excitability. This technique requires the injection of current into the cell and is dependent on the real-time feedback of its membrane potential at that time. The injected current is calculated from predetermined excitatory and inhibitory synaptic conductances, their reversal potentials and the cell's instantaneous membrane potential. Details on the experimental procedures, patch clamping cells to achieve a whole-cell configuration and employment of the dynamic clamp technique are illustrated in this video article. Here, we show the responses of mouse retinal ganglion cells to various conductance waveforms obtained from physiological experiments in control conditions or in the presence of drugs. Furthermore, we show the use of artificial excitatory and inhibitory conductances generated using alpha functions to investigate the responses of the cells.

  20. Effect of delayed cord clamping on very preterm infants.

    Science.gov (United States)

    Chiruvolu, Arpitha; Tolia, Veeral N; Qin, Huanying; Stone, Genna Leal; Rich, Diana; Conant, Rhoda J; Inzer, Robert W

    2015-11-01

    Despite significant proposed benefits, delayed umbilical cord clamping (DCC) is not practiced widely in preterm infants largely because of the question of feasibility of the procedure and uncertainty regarding the magnitude of the reported benefits, especially intraventricular hemorrhage (IVH) vs the adverse consequences of delaying the neonatal resuscitation. The objective of this study was to determine whether implementation of the protocol-driven DCC process in our institution would reduce the incidence of IVH in very preterm infants without adverse consequences. We implemented a quality improvement process for DCC the started in August 2013 in infants born at ≤32 weeks' gestational age. Eligible infants were left attached to the placenta for 45 seconds after birth. Neonatal process and outcome data were collected until discharge. We compared infants who received DCC who were born between August 2013 and August 2014 with a historic cohort of infants who were born between August 2012 and August 2013, who were eligible to receive DCC, but whose cord was clamped immediately after birth, because they were born before the protocol implementation. DCC was performed on all the 60 eligible infants; 88 infants were identified as historic control subjects. Gestational age, birthweight, and other demographic variables were similar between both groups. There were no differences in Apgar scores or admission temperature, but significantly fewer infants in the DCC cohort were intubated in delivery room, had respiratory distress syndrome, or received red blood cell transfusions in the first week of life compared with the historic cohort. A significant reduction was noted in the incidence of IVH in the DCC cohort compared with the historic control group (18.3% vs 35.2%). After adjustment for gestational age, an association was found between the incidence of IVH and DCC with IVH was significantly lower in the DCC cohort compared with the historic cohort; an odds ratio of 0

  1. On the mechanism of loading the PCNA sliding clamp by RFC.

    Science.gov (United States)

    Dionne, Isabelle; Brown, Nicola J; Woodgate, Roger; Bell, Stephen D

    2008-04-01

    Sliding clamps play central roles in a broad range of DNA replication and repair processes. The clamps form circular molecules that must be opened and resealed around DNA by the clamp loader complex to fulfil their function. While most eukaryotes and many archea possess a homo-trimeric PCNA, the PCNA of Sulfolobus solfataricus is a heterotrimer. Here, we exploit the asymmetry of S. solfataricus PCNA to create a series of circularly permuted PCNA subunit fusions, thereby covalently closing defined interfaces within the heterotrimer. Using these concatamers, we investigate the requirements for loading the clamp onto DNA and reveal that a single defined interface within the heterotrimer is opened during the loading process. Subunit-specific interactions between S. solfataricus RFC clamp loader and PCNA permit us to superimpose our data upon the structure of yeast RFC-PCNA complex, thereby presenting a general model for PCNA loading by RFC in archaea and eukaryotes.

  2. A reduction clamp for an aiming component in associated acetabular fractures

    Directory of Open Access Journals (Sweden)

    Zhang-Fu Wang

    2015-01-01

    Full Text Available Background: The treatment of acetabular fractures is complex and requires specialized equipment. However, all currently available instruments have some disadvantages. A new reduction clamp that can firmly enable reduction and not hinder subsequent fixation procedures for some special fracture types is needed. Materials and Methods: In this study, we introduce a new acetabular clamp and its preliminary clinical application in three T-shaped acetabular fractures. Results: This new clamp can successfully pull the posterior column back to the anterior column and firmly maintain the reduction. This clamp′s aiming plate can facilitate the insertion of long lag screws. The clamp is also easy to assemble and use. Conclusion: This reduction clamp is a useful instrument that can facilitate open reduction and internal fixation of acetabular fractures.

  3. The deformation of an elastic rod with a clamp sliding along a smooth and curved profile

    CERN Document Server

    Misseroni, D; Zaccaria, D; Bigoni, D

    2015-01-01

    The design of compliant mechanisms is crucial in several technologies and relies on the availability of solutions for nonlinear structural problems. One of these solutions is given and experimentally validated in the present article for a compliant mechanism moving along a smooth curved profile. In particular, a deformable elastic rod is held by two clamps, one at each end. The first clamp is constrained to slide without friction along a curved profile, while the second clamp moves in a straight line transmitting its motion through the elastic rod to the first clamp. For this system it is shown that the clamp sliding on the profile imposes nontrivial boundary conditions (derived via a variational and an asymptotic approach), which strongly influence buckling and nonlinear structural behaviour. Investigation of this behaviour shows that a compliant mechanism can be designed, which gives an almost neutral response in compression. This behavior could easily be exploited to make a force limiting device. Finally a...

  4. Note: High-efficiency energy harvester using double-clamped piezoelectric beams

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yingmei; Wu, Xuan; Parmar, Mitesh; Lee, Dong-weon, E-mail: mems@jnu.ac.kr [MEMS and Nanotechnology Laboratory, School of Mechanical Systems Engineering, Chonnam National University, Gwangju (Korea, Republic of)

    2014-02-15

    In this study, an improvement in energy conversion efficiency has been reported, which is realized by using a double-clamped piezoelectric beam, based on uniaxial stretching strain. The buckling mechanism is applied to maximize axial stress in the double-clamped beam. The voltage generated by using the double-clamped piezoelectric beam is higher than that generated by using other conventional structures, such as bending cantilevers coated/sandwiched with piezoelectric film, which is proven both theoretically and experimentally. The power generation efficiency is enhanced by further optimizing the double-clamped structure. The optimized high-efficiency energy harvester utilizing double-clamped piezoelectric beams generates a peak output power of 80 μW, under an acceleration of 0.1g.

  5. Note: high-efficiency energy harvester using double-clamped piezoelectric beams.

    Science.gov (United States)

    Zheng, Yingmei; Wu, Xuan; Parmar, Mitesh; Lee, Dong-weon

    2014-02-01

    In this study, an improvement in energy conversion efficiency has been reported, which is realized by using a double-clamped piezoelectric beam, based on uniaxial stretching strain. The buckling mechanism is applied to maximize axial stress in the double-clamped beam. The voltage generated by using the double-clamped piezoelectric beam is higher than that generated by using other conventional structures, such as bending cantilevers coated/sandwiched with piezoelectric film, which is proven both theoretically and experimentally. The power generation efficiency is enhanced by further optimizing the double-clamped structure. The optimized high-efficiency energy harvester utilizing double-clamped piezoelectric beams generates a peak output power of 80 μW, under an acceleration of 0.1g.

  6. Dynamics of a clamped–clamped microbeam resonator considering fabrication imperfections

    KAUST Repository

    Bataineh, Ahmad M.

    2014-10-18

    We present an investigation into the static and dynamic behavior of an electrostatically actuated clamped–clamped polysilicon microbeam resonator accounting for its fabrication imperfections, which are commonly encountered in similar microstructures. These are mainly because of the initial deformation of the beam due to stress gradient and its flexible anchors. First, we show experimental data of the microbeam when driven electrically by varying the amplitude and frequency of the voltage loads. The results reveal several interesting nonlinear phenomena of jumps, hysteresis, and softening behaviors. Theoretical investigation is then conducted to model the microbeam, and hence, interpret the experimental data. We solve the Eigen value problem governing the natural frequencies analytically. We then utilize a Galerkin-based procedure to derive a reduced order model, which is then used to simulate both the static and dynamic responses. To achieve good matching between theory and experiment, we show that the exact profile of the deformed beam needs to be utilized in the reduced order model, as measured from the optical profiler, combined with a shooting technique simulation, which is capable of tracing the resonant frequency branches under very-low damping conditions.

  7. Effects of Delayed Umbilical Cord Clamping vs Early Clamping on Anemia in Infants at 8 and 12 Months: A Randomized Clinical Trial.

    Science.gov (United States)

    Kc, Ashish; Rana, Nisha; Målqvist, Mats; Jarawka Ranneberg, Linda; Subedi, Kalpana; Andersson, Ola

    2017-03-01

    Delayed umbilical cord clamping has been shown to improve iron stores in infants to 6 months of age. However, delayed cord clamping has not been shown to prevent iron deficiency or anemia after 6 months of age. To investigate the effects of delayed umbilical cord clamping, compared with early clamping, on hemoglobin and ferritin levels at 8 and 12 months of age in infants at high risk for iron deficiency anemia. This randomized clinical trial included 540 late preterm and term infants born vaginally at a tertiary hospital in Kathmandu, Nepal, from October 2 to November 21, 2014. Follow-up included blood levels of hemoglobin and ferritin at 8 and 12 months of age. Follow-up was completed on December 11, 2015. Analysis was based on intention to treat. Infants were randomized to delayed umbilical cord clamping (≥180 seconds after delivery) or early clamping (≤60 seconds after delivery). Main outcomes included hemoglobin and anemia levels at 8 months of age with the power estimate based on the prevalence of anemia. Secondary outcomes included hemoglobin and anemia levels at 12 months of age and ferritin level, iron deficiency, and iron deficiency anemia at 8 and 12 months of age. In this study of 540 infants (281 boys [52.0%] and 259 girls [48.0%]; mean [SD] gestational age, 39.2 [1.1] weeks), 270 each were randomized to the delayed and early clamping groups. At 8 months of age, 212 infants (78.5%) from the delayed group and 188 (69.6%) from the early clamping group returned for blood sampling. After multiple imputation analysis, infants undergoing delayed clamping had higher levels of hemoglobin (10.4 vs 10.2 g/dL; difference, 0.2 g/dL; 95% CI, 0.1 to 0.4 g/dL). Delayed cord clamping also reduced the prevalence of anemia (hemoglobin level clamping group in 60 (22.2%) vs 103 (38.1%) patients (relative risk, 0.58; 95% CI, 0.44-0.77; NNT, 6; 95% CI, 4-13). At 12 months, delayed cord clamping still resulted in a hemoglobin level of 0.3 (95% CI, 0.04-0.5) g/dL higher

  8. Photoelectric angle converter

    Science.gov (United States)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  9. Simultaneous patch-clamping and calcium imaging in developing dendrites.

    Science.gov (United States)

    Kleindienst, Thomas; Lohmann, Christian

    2014-03-01

    Calcium imaging has been used extensively to explore the role of action potential (AP) firing in the development of neuronal structure and synaptic function because increases in intracellular calcium ([Ca(2+)]i) reliably and, within a certain range, linearly reflect neuronal spiking activity. Patterns of APs in individual cells can be deduced from calcium recordings, which have typically been performed at the level of cell bodies. However, neurons are particularly susceptible to phototoxicity when they are illuminated at the soma. Furthermore, for some imaging experiments (e.g., those that address the interactions between dendrites and axons during synapse formation), the cell body of a given neuron may simply not be in the field of view. In these situations, it would be helpful to determine the spiking patterns of a neuron from the calcium activity in its subcellular compartments such as stretches of dendrites or axons. Here, we describe an approach for determining the relationship between AP firing and dendritic calcium transients by simultaneously imaging calcium transients in small dendritic stretches of hippocampal pyramidal neurons in slice cultures from neonatal rats and recording spiking activity with whole-cell patch-clamp recordings in these neurons. These experiments allow us to correlate the electrophysiological spiking pattern with the accompanying changes in the calcium concentration in individual dendritic segments.

  10. Non-Hookean statistical mechanics of clamped graphene ribbons

    Science.gov (United States)

    Bowick, Mark J.; Košmrlj, Andrej; Nelson, David R.; Sknepnek, Rastko

    2017-03-01

    Thermally fluctuating sheets and ribbons provide an intriguing forum in which to investigate strong violations of Hooke's Law: Large distance elastic parameters are in fact not constant but instead depend on the macroscopic dimensions. Inspired by recent experiments on free-standing graphene cantilevers, we combine the statistical mechanics of thin elastic plates and large-scale numerical simulations to investigate the thermal renormalization of the bending rigidity of graphene ribbons clamped at one end. For ribbons of dimensions W ×L (with L ≥W ), the macroscopic bending rigidity κR determined from cantilever deformations is independent of the width when W ℓth , however, this thermally renormalized bending rigidity begins to systematically increase, in agreement with the scaling theory, although in our simulations we were not quite able to reach the system sizes necessary to determine the fully developed power law dependence on W . When the ribbon length L >ℓp , where ℓp is the W -dependent thermally renormalized ribbon persistence length, we observe a scaling collapse and the beginnings of large scale random walk behavior.

  11. Umbilical Cord Milking Versus Delayed Cord Clamping in Preterm Infants.

    Science.gov (United States)

    Katheria, Anup C; Truong, Giang; Cousins, Larry; Oshiro, Bryan; Finer, Neil N

    2015-07-01

    Delayed cord clamping (DCC) is recommended for premature infants to improve blood volume. Most preterm infants are born by cesarean delivery (CD), and placental transfusion may be less effective than in vaginal delivery (VD). We sought to determine whether infants umbilical cord milking (UCM) have higher measures of systemic blood flow than infants who undergo DCC. This was a 2-center trial. Infants delivered by CD were randomly assigned to undergo UCM or DCC. Infants delivered by VD were also randomly assigned separately. UCM (4 strippings) or DCC (45-60 seconds) were performed. Continuous hemodynamic measurements and echocardiography were done at site 1. A total of 197 infants were enrolled (mean gestational age 28 ± 2 weeks). Of the 154 infants delivered by CD, 75 were assigned to UCM and 79 to DCC. Of the infants delivered by CD, neonates randomly assigned to UCM had higher superior vena cava flow and right ventricular output in the first 12 hours of life. Neonates undergoing UCM also had higher hemoglobin, delivery room temperature, blood pressure over the first 15 hours, and urine output in the first 24 hours of life. There were no differences for the 43 infants delivered by VD. This is the first randomized controlled trial demonstrating higher systemic blood flow with UCM in preterm neonates compared with DCC. UCM may be a more efficient technique to improve blood volume in premature infants delivered by CD. Copyright © 2015 by the American Academy of Pediatrics.

  12. An optogenetics- and imaging-assisted simultaneous multiple patch-clamp recording system for decoding complex neural circuits.

    Science.gov (United States)

    Wang, Guangfu; Wyskiel, Daniel R; Yang, Weiguo; Wang, Yiqing; Milbern, Lana C; Lalanne, Txomin; Jiang, Xiaolong; Shen, Ying; Sun, Qian-Quan; Zhu, J Julius

    2015-03-01

    Deciphering neuronal circuitry is central to understanding brain function and dysfunction, yet it remains a daunting task. To facilitate the dissection of neuronal circuits, a process requiring functional analysis of synaptic connections and morphological identification of interconnected neurons, we present here a method for stable simultaneous octuple patch-clamp recordings. This method allows physiological analysis of synaptic interconnections among 4-8 simultaneously recorded neurons and/or 10-30 sequentially recorded neurons, and it allows anatomical identification of >85% of recorded interneurons and >99% of recorded principal neurons. We describe how to apply the method to rodent tissue slices; however, it can be used on other model organisms. We also describe the latest refinements and optimizations of mechanics, electronics, optics and software programs that are central to the realization of a combined single- and two-photon microscopy-based, optogenetics- and imaging-assisted, stable, simultaneous quadruple-viguple patch-clamp recording system. Setting up the system, from the beginning of instrument assembly and software installation to full operation, can be completed in 3-4 d.

  13. Note: A gel based imaging technique of the iridocorneal angle for evaluation of angle-closure glaucoma

    Science.gov (United States)

    Shinoj, V. K.; Murukeshan, V. M.; Baskaran, M.; Aung, T.

    2014-06-01

    Noninvasive medical imaging techniques have high potential in the field of ocular imaging research. Angle closure glaucoma is a major disease causing blindness and a possible way of detection is the examination of the anterior chamber angle in eyes. Here, a simple optical method for the evaluation of angle-closure glaucoma is proposed and illustrated. The light propagation from the region associated with the iridocorneal angle to the exterior of eye is considered analytically. The design of the gel assisted probe prototype is carried out and the imaging of iridocorneal angle is performed on an eye model.

  14. Angle-Ply Weaving

    Science.gov (United States)

    Farley, Gary L.

    1990-01-01

    Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.

  15. Variations of refraction angles from observations of the Moon from space.

    Science.gov (United States)

    Kireev, S V; Sokolovskiy, S V

    1994-12-20

    We present the results of measurements of optical refraction angles from photographs of the Moon taken from the orbital station Mir. We made estimations of rms fluctuations of refraction angles and of the characteristics of multipath propagation.

  16. Committee Opinion No. 684 Summary: Delayed Umbilical Cord Clamping After Birth.

    Science.gov (United States)

    2017-01-01

    Delayed umbilical cord clamping appears to be beneficial for term and preterm infants. In term infants, delayed umbilical cord clamping increases hemoglobin levels at birth and improves iron stores in the first several months of life, which may have a favorable effect on developmental outcomes. There is a small increase in jaundice that requires phototherapy in this group of infants. Consequently, health care providers adopting delayed umbilical cord clamping in term infants should ensure that mechanisms are in place to monitor for and treat neonatal jaundice. In preterm infants, delayed umbilical cord clamping is associated with significant neonatal benefits, including improved transitional circulation, better establishment of red blood cell volume, decreased need for blood transfusion, and lower incidence of necrotizing enterocolitis and intraventricular hemorrhage. Delayed umbilical cord clamping was not associated with an increased risk of postpartum hemorrhage or increased blood loss at delivery, nor was it associated with a difference in postpartum hemoglobin levels or the need for blood transfusion. Given the benefits to most newborns and concordant with other professional organizations, the American College of Obstetricians and Gynecologists now recommends a delay in umbilical cord clamping in vigorous term and preterm infants for at least 30-60 seconds after birth. The ability to provide delayed umbilical cord clamping may vary among institutions and settings; decisions in those circumstances are best made by the team caring for the mother-infant dyad.

  17. Committee Opinion No.543: Timing of umbilical cord clamping after birth.

    Science.gov (United States)

    2012-12-01

    The optimal timing for clamping the umbilical cord after birth has been a subject of controversy and debate. Although many randomized controlled trials in term and preterm infants have evaluated the benefits of delayed umbilical cord clamping versus immediate umbilical cord clamping, the ideal timing for cord clamping has yet to be established. Several systematic reviews have suggested that clamping the umbilical cord in all births should be delayed for at least 30-60 seconds, with the infant maintained at or below the level of the placenta because of the associated neonatal benefits, including increased blood volume, reduced need for blood transfusion, decreased incidence of intracranial hemorrhage in preterm infants, and lower frequency of iron deficiency anemia in term infants. Evidence exists to support delayed umbilical cord clamping in preterm infants, when feasible. The single most important clinical benefit for preterm infants is the possibility for a nearly 50% reduction in intraventricular hemorrhage. However, currently, evidence is insufficient to confirm or refute the potential for benefits from delayed umbilical cord clamping in term infants, especially in settings with rich resources.

  18. Blood gas values in clamped and unclamped umbilical cord at birth.

    Science.gov (United States)

    Di Tommaso, Mariarosaria; Seravalli, Viola; Martini, Irene; La Torre, Pasquale; Dani, Carlo

    2014-09-01

    To determine the reliability of the cord blood gas analysis on the unclamped cord compared to the standard technique of sampling on double clamped cord. Prospective observational study conducted on 46 singleton neonates vaginally delivered at term. Matched pairs of umbilical artery and vein blood samples were collected from unclamped cord within 90s after birth and from the same cord after clamping, with the clamping occurring immediately after the first blood collection. A blood gas analysis was performed on each collected sample. Arterial and venous blood samples were analyzed for pH, PO2, pCO2, SaO2, hemoglobin concentration (ctHb) and base excess (BE). The values were compared between the two groups (clamped vs unclamped) using a Wilcoxon test. No significant difference was found in pH, PO2, pCO2, SaO2 and ctHb values on arterial blood between unclamped and clamped cord. The only significant difference was related to BE (pblood, the values of pH, PO2, pCO2 were comparable between unclamped and clamped cord, while the values of SaO2, ctHb and BE were significantly different (pblood gas parameters and in the main venous blood gas parameters between unclamped and clamped cord. Sampling of cord blood for gas analysis may be performed on the unclamped cord right after birth without reducing the accuracy of the analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Immunologic and infectious consequences of immediate versus delayed umbilical cord clamping in premature infants: a prospective, randomized, controlled study.

    Science.gov (United States)

    Kugelman, Amir; Borenstein-Levin, Liron; Kessel, Aharon; Riskin, Arieh; Toubi, Elias; Bader, David

    2009-01-01

    To evaluate the immunologic and infectious consequences of delayed versus immediate cord clamping in premature infants (cord clamping (ICC) at 5-10 s and 30 infants to delayed cord clamping (DCC), at 30-45 s (14 and 15 infants in each group were cord clamping did not affect the immunologic or the infectious status of infants born at <35 weeks during the neonatal period.

  20. Angle dependence of Andreev scattering at semiconductor-superconductor interfaces

    DEFF Research Database (Denmark)

    Mortensen, Asger; Flensberg, Karsten; Jauho, Antti-Pekka

    1999-01-01

    and increase of the probability of normal reflection. We show that in the presence of a Fermi velocity mismatch between the semiconductor and the superconductor the angles of incidence and transmission are related according to the well-known Snell's law in optics. As a consequence there is a critical angle...

  1. Engineering sidewall angles of silica-on-silicon waveguides

    DEFF Research Database (Denmark)

    Haiyan, Ou

    2004-01-01

    Burned photoresist is used as etch mask when producing silica-onsilicon waveguides. The sidewall angle of the optical glass waveguides is engineered by varying photoresist thickness and etch selectivity. The principle for the formation of the angles is introduced and very promising experimental...

  2. A Central Swivel Point in the RFC Clamp Loader Controls PCNA Opening and Loading on DNA

    OpenAIRE

    Sakato, Miho; O’Donnell, Mike; Hingorani, Manju M.

    2011-01-01

    Replication Factor C (RFC) is a 5-subunit complex that loads PCNA clamps onto primer-template DNA (ptDNA) during replication. RFC subunits belong to the AAA+ superfamily, and their ATPase activity drives interactions between the clamp loader, clamp, and ptDNA, leading to topologically linked PCNA•ptDNA. We report the kinetics of transient events in S. cerevisiae RFC catalyzed PCNA loading, including ATP-induced RFC activation, PCNA opening, ptDNA binding, ATP hydrolysis, PCNA closing and PCNA...

  3. Characterization of potassium channel modulators with QPatch automated patch-clamp technology: system characteristics and performance

    DEFF Research Database (Denmark)

    Kutchinsky, Jonatan; Friis, Søren; Asmild, Margit

    2003-01-01

    Planar silicon chips with 1-2-microm etched holes (average resistance: 2.04 +/- 0.02 MOmega in physiological buffer, n = 274) have been developed for patch-clamp recordings of whole-cell currents from cells in suspension. An automated 16-channel parallel screening system, QPatch 16, has been...... developed using this technology. A single-channel prototype of the QPatch system was used for validation of the patch-clamp chip technology. We present here data on the quality of patch-clamp recordings and from actual drug screening studies of human potassium channels expressed in cultured cell lines...

  4. Modelling the clamping force distribution among chips in press-pack IGBTs using the finite element method

    DEFF Research Database (Denmark)

    Hasmasan, Adrian Augustin; Busca, Christian; Teodorescu, Remus

    2012-01-01

    In this paper, a FEM (finite element method) based mechanical model for PP (press-pack) IGBTs (insulated gate bipolar transistors) is presented, which can be used to calculate the clamping force distribution among chips under various clamping conditions. The clamping force is an important paramet...

  5. Femtogram Doubly Clamped Nanomechanical Resonators Embedded in a High-Q Two-Dimensional Photonic Crystal Nanocavity

    CERN Document Server

    Sun, Xiankai; Poot, Menno; Wong, Chee Wei; Tang, Hong X

    2012-01-01

    We demonstrate a new optomechanical device system which allows highly efficient transduction of femtogram nanobeam resonators. Doubly clamped nanomechanical resonators with mass as small as 25 fg are embedded in a high-finesse two-dimensional photonic crystal nanocavity. Optical transduction of the fundamental flexural mode around 1 GHz was performed at room temperature and ambient conditions, with an observed displacement sensitivity of 0.94 fm/Hz^(1/2). Comparison of measurements from symmetric and asymmetric double-beam devices reveals hybridization of the mechanical modes where the structural symmetry is shown to be the key to obtain a high mechanical quality factor. Our novel configuration opens the way for a new category of "NEMS-in-cavity" devices based on optomechanical interaction at the nanoscale.

  6. Limited Angle Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Kyung; Cho, Min Kook; Kim, Seong Sik [Pusan National University, Busan (Korea, Republic of)

    2007-07-01

    In computed tomography (CT), many situations are restricted to obtain enough number of projections or views to avoid artifacts such as streaking and geometrical distortion in the reconstructed images. Speed of motion of an object to be imaged can limit the number of views. Cardiovascular imaging is a representative example. Size of an object can also limit the complete traverse motion or geometrical complexity can obscure to be imaged at certain range of angles. These situations are frequently met in industrial nondestructive testing and evaluation. Dental CT also suffers from similar situation because cervical spine causes less x-ray penetration from some directions such that the available information is not sufficient for standard reconstruction algorithms. The limited angle tomography is now greatly paid attention as a new genre in medical and industrial imaging, popularly known as digital tomosynthesis. In this study, we introduce a modified filtered backprojection method in limited angle tomography and demonstrate its application for the dental imaging.

  7. Dynamical angled brane

    Science.gov (United States)

    Maeda, Kei-ichi; Uzawa, Kunihito

    2016-12-01

    We discuss the dynamical D p -brane solutions describing any number of D p branes whose relative orientations are given by certain SU(2) rotations. These are the generalization of the static angled D p -brane solutions. We study the collision of the dynamical D3 brane with angles in type-II string theory, and show that the particular orientation of the smeared D3-brane configuration can provide an example of colliding branes if they have the same charges. Otherwise a singularity appears before D3 branes collide.

  8. Magneto-optical metamaterial

    CERN Document Server

    Sadatgol, Mehdi; Forati, Ebrahim; Levy, Miguel; Guney, Durdu O

    2015-01-01

    We propose a new class of metamaterials called magneto-optical metamaterials that offer enhanced angle of rotation in polarization compared to bulk magneto-optical materials. In the proposed approach, the permittivity tensor of a magneto-optical material is tailored by embedded wire meshes behaving as artificial plasma. We have shown that the angle of rotation in the magneto-optical metamaterial can be enhanced up to 9 times compared to bulk magneto-optical material alone while the polarization extinction ratio remains below -20dB and insertion loss is less than 1.5dB.

  9. Electrosurgical bipolar vessel sealing versus conventional clamping and suturing for total abdominal hysterectomy: a randomized trial.

    NARCIS (Netherlands)

    Lakeman, M.; Kruitwagen, R.F.P.M.; Vos, M.C.; Roovers, J.P.

    2008-01-01

    STUDY OBJECTIVE: To compare the effects of bipolar vessel sealing versus conventional clamping and suturing in women undergoing total abdominal hysterectomy. DESIGN: A randomized controlled trial was performed. Patients were randomized to vessel sealing or conventional surgery. Postoperative pain wa

  10. Common voltage eliminating of SVM diode clamping three-level inverter connected to grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    A novel method of common voltage eliminating is put forward for SVM diode clamping three-level inverter connected to grid by calculation of common voltage of its various switching states. PLECS is used to model this three-level inverter connected to grid and good results are obtained. First...... analysis of common mode voltage for switching states of diode clamping 3-level inverter is given in detail. Second the common mode voltage eliminating control strategy of SVM is described for diode clamping three-level inverter. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping...... three-level inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is a very powerful tool to real power circuits modeling. They have also verified that proposed common mode voltage eliminating control strategy of SVM is feasible...

  11. Renal perfusion with venous blood extends the permissible suprarenal clamp time in abdominal aortic surgery

    National Research Council Canada - National Science Library

    Pichlmaier, Maximilian; Hoy, Ludwig; Wilhelmi, Mathias; Khaladj, Nawid; Haverich, Axel; Teebken, Omke E

    2008-01-01

    ... suprarenal clamping for aortic reconstructive surgery. Renal perfusion was achieved using a roller pump supplied with venous blood from a central venous catheter under medium-level heparinization to feed two perfusion balloon catheters...

  12. Suppression of Spiral Waves by Voltage Clamp Techniques in a Conductance-Based Cardiac Tissue Model

    Institute of Scientific and Technical Information of China (English)

    YU Lian-Chun; MA Jun; ZHANG Guo-Yong; CHEN Yong

    2008-01-01

    A new control method is proposed to control the spatio-temporal dynamics in excitable media, which is described by the Morris-Lecar cells model. It is confirmed that successful suppression of spiral waves can be obtained by spatially clamping the membrane voltage of the excitable cells. The low voltage clamping induces breakup of spiral waves and the fragments are soon absorbed by low voltage obstacles, whereas the high voltage clamping generates travel waves that annihilate spiral waves through collision with them. However, each method has its shortcomings. Furthermore, a two-step method that combines both low and high voltage clamp techniques is then presented as a possible way of out this predicament.

  13. Implementation of a fast 16-Bit dynamic clamp using LabVIEW-RT.

    Science.gov (United States)

    Kullmann, Paul H M; Wheeler, Diek W; Beacom, Joshua; Horn, John P

    2004-01-01

    The dynamic-clamp method provides a powerful electrophysiological tool for creating virtual ionic conductances in living cells and studying their influence on membrane potential. Here we describe G-clamp, a new way to implement a dynamic clamp using the real-time version of the Lab-VIEW programming environment together with a Windows host, an embedded microprocessor that runs a real-time operating system and a multifunction data-acquisition board. The software includes descriptions of a fast voltage-dependent sodium conductance, delayed rectifier, M-type and A-type potassium conductances, and a leak conductance. The system can also read synaptic conductance waveforms from preassembled data files. These virtual conductances can be reliably implemented at speeds LabVIEW should make it relatively easy for others to adapt G-clamp for new experimental applications.

  14. Modeling CICR in rat ventricular myocytes: voltage clamp studies

    Directory of Open Access Journals (Sweden)

    Palade Philip T

    2010-11-01

    Full Text Available Abstract Background The past thirty-five years have seen an intense search for the molecular mechanisms underlying calcium-induced calcium-release (CICR in cardiac myocytes, with voltage clamp (VC studies being the leading tool employed. Several VC protocols including lowering of extracellular calcium to affect Ca2+ loading of the sarcoplasmic reticulum (SR, and administration of blockers caffeine and thapsigargin have been utilized to probe the phenomena surrounding SR Ca2+ release. Here, we develop a deterministic mathematical model of a rat ventricular myocyte under VC conditions, to better understand mechanisms underlying the response of an isolated cell to calcium perturbation. Motivation for the study was to pinpoint key control variables influencing CICR and examine the role of CICR in the context of a physiological control system regulating cytosolic Ca2+ concentration ([Ca2+]myo. Methods The cell model consists of an electrical-equivalent model for the cell membrane and a fluid-compartment model describing the flux of ionic species between the extracellular and several intracellular compartments (cell cytosol, SR and the dyadic coupling unit (DCU, in which resides the mechanistic basis of CICR. The DCU is described as a controller-actuator mechanism, internally stabilized by negative feedback control of the unit's two diametrically-opposed Ca2+ channels (trigger-channel and release-channel. It releases Ca2+ flux into the cyto-plasm and is in turn enclosed within a negative feedback loop involving the SERCA pump, regulating[Ca2+]myo. Results Our model reproduces measured VC data published by several laboratories, and generates graded Ca2+ release at high Ca2+ gain in a homeostatically-controlled environment where [Ca2+]myo is precisely regulated. We elucidate the importance of the DCU elements in this process, particularly the role of the ryanodine receptor in controlling SR Ca2+ release, its activation by trigger Ca2+, and its

  15. Patch Clamp: A Powerful Technique for Studying the Mechanism of Acupuncture

    Directory of Open Access Journals (Sweden)

    D. Zhang

    2012-01-01

    Full Text Available Cellular and molecular events can be investigated using electrophysiological techniques. In particular, the patch-clamp method provides detailed information. In addition, the patch-clamp technique has become a powerful method for investigating the mechanisms underlying the effects of acupuncture. In this paper, recent researches on how acupuncture might modulate electrophysiological responses in the central nervous system (CNS and affect peripheral structures are reviewed.

  16. Delayed umbilical cord clamping after childbirth: potential benefits to baby's health

    Directory of Open Access Journals (Sweden)

    Uwins C

    2014-11-01

    Full Text Available Christina Uwins,1 David JR Hutchon2 1Department of Obstetrics and Gynaecology, Croydon University Hospital, Croydon, 2Department of Obstetrics, Darlington Memorial Hospital, Darlington, UKAbstract: Early cord clamping was initially introduced as part of the package of care known as “active management of the third stage”, which was implemented to reduce postpartum hemorrhage. It has now been shown to provide no benefit to the mother and to result in harm to the neonate. The clinical trial evidence relating to delayed cord clamping compared to immediate cord clamping is presented and the physiological rationale for delayed cord clamping is discussed in this paper. Most organizations (eg World Health Organization (WHO, Royal College of Obstetricians and Gynaecologists (RCOG, Resuscitation Council (UK,The International Federation of Gynecology and Obstetrics (FIGO, International Confederation of Midwives, International Liaison Committee on Resuscitation (ILCOR and the European Resuscitation Council now advise a delay of 1–3 minutes before clamping the cord in term and preterm infants, and clinicians need to be aware of this change. Healthy neonates benefit from a more physiological and gentle transition from placental to pulmonary respiration, and we explain why this benefit should be provided to all neonates until there is any evidence to the contrary. The harm of early cord clamping is not limited to anemia and iron deficiency, and evidence for a wide range of possible harms of early cord clamping is presented. The need for resuscitation is one of the most common concerns, and ways of overcoming these concerns are described.Keywords: transition, cord clamping, hypovolemia, intraventricular hemorrhage

  17. The quadriceps angle

    DEFF Research Database (Denmark)

    Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona

    2012-01-01

    : Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...

  18. Effect of non-ideal clamping shape on the resonance frequencies of silicon nanocantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Guillon, Samuel; Saya, Daisuke; Mazenq, Laurent; Nicu, Liviu [CNRS, LAAS, 7 Avenue du Colonel Roche, F-31077 Toulouse Cedex 4 (France); Perisanu, Sorin; Vincent, Pascal [LPMCN, Universite Claude Bernard Lyon 1 et CNRS, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Lazarus, Arnaud; Thomas, Olivier, E-mail: sguillon@laas.fr [Structural Mechanics and Coupled Systems Laboratory, Conservatoire National des Arts et Metiers, 2 rue Conte, 75003 Paris (France)

    2011-06-17

    In this paper, we investigate the effects of non-ideal clamping shapes on the dynamic behavior of silicon nanocantilevers. We fabricated silicon nanocantilevers using silicon on insulator (SOI) wafers by employing stepper ultraviolet (UV) lithography, which permits a resolution of under 100 nm. The nanocantilevers were driven by electrostatic force inside a scanning electron microscope (SEM). Both lateral and out-of-plane resonance frequencies were visually detected with the SEM. Next, we discuss overhanging of the cantilever support and curvature at the clamping point in the silicon nanocantilevers, which generally arises in the fabrication process. We found that the fundamental out-of-plane frequency of a realistically clamped cantilever is always lower than that for a perfectly clamped cantilever, and depends on the cantilever width and the geometry of the clamping point structure. Using simulation with the finite-elements method, we demonstrate that this discrepancy is attributed to the particular geometry of the clamping point (non-zero joining curvatures and a flexible overhanging) that is obtained in the fabrication process. The influence of the material orthotropy is also investigated and is shown to be negligible.

  19. A novel monolithic piezoelectric actuated flexure-mechanism based wire clamp for microelectronic device packaging

    Science.gov (United States)

    Liang, Cunman; Wang, Fujun; Tian, Yanling; Zhao, Xingyu; Zhang, Hongjie; Cui, Liangyu; Zhang, Dawei; Ferreira, Placid

    2015-04-01

    A novel monolithic piezoelectric actuated wire clamp is presented in this paper to achieve fast, accurate, and robust microelectronic device packaging. The wire clamp has compact, flexure-based mechanical structure and light weight. To obtain large and robust jaw displacements and ensure parallel jaw grasping, a two-stage amplification composed of a homothetic bridge type mechanism and a parallelogram leverage mechanism was designed. Pseudo-rigid-body model and Lagrange approaches were employed to conduct the kinematic, static, and dynamic modeling of the wire clamp and optimization design was carried out. The displacement amplification ratio, maximum allowable stress, and natural frequency were calculated. Finite element analysis (FEA) was conducted to evaluate the characteristics of the wire clamp and wire electro discharge machining technique was utilized to fabricate the monolithic structure. Experimental tests were carried out to investigate the performance and the experimental results match well with the theoretical calculation and FEA. The amplification ratio of the clamp is 20.96 and the working mode frequency is 895 Hz. Step response test shows that the wire clamp has fast response and high accuracy and the motion resolution is 0.2 μm. High speed precision grasping operations of gold and copper wires were realized using the wire clamper.

  20. A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2012-12-01

    Full Text Available In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits have lower switching losses and minimum ringing voltage of the active switches. Thus, the proposed IBCC with active-clamp circuits for wind energy conversion can significantly increase conversion efficiency. Finally, a 240 W prototype of the proposed IBCC with active-clamp circuits was built and implemented. Experimental results have shown that efficiency can reach as high as 91%. The proposed IBCC with active-clamp circuits is presented in high step-down voltage applications to verify the performance and the feasibility for energy conversion of wind turbines.

  1. The effect of early and late umbilical cord clamping on neonatal hematocrit.

    Science.gov (United States)

    Jahazi, A; Kordi, M; Mirbehbahani, N B; Mazloom, S R

    2008-08-01

    To compare the effect of early and late cord clamping (LCC) on neonatal hematocrit at 2 and 18 h of life. In this double-blind randomized trial, 64 healthy full-term vaginally born neonates were randomly allocated to either early (30 s) or late (3 min) umbilical cord clamping. During the interval between delivery and cord clamping, the attendant held the neonate supine at the level of the introitus. Neonatal venous hematocrit was measured at 2 and 18 h of life. Neonatal hematocrit at 2 h of life (61+/-4.9 vs 61.6+/-4.5%) and 18 h of life (56.9+/-4.1 vs 56.2+/-3.9%) was not significantly different between the two groups. This was also true for neonatal polycythemia (20 vs 23.5%). In the LCC group, placental residual blood volume (PRBV) was 39.5% lower and estimated neonatal blood volume (ENBV) was 7.1% higher than that in the early cord clamping (ECC) group (Pcord clamping does not lead to a significant difference in the hematocrit level of the neonate or neonatal polycythemia, but is associated with a significant increase in ENBV and a significant decrease in PRBV. Further trials should examine the effect of delaying cord clamping for a longer period of time or changing the position that the neonate is held in to determine whether these variations result in more clinically significant results.

  2. Late umbilical cord clamping, neonatal hematocrit and Apgar scores: a randomized controlled trial.

    Science.gov (United States)

    Salari, Z; Rezapour, M; Khalili, N

    2014-01-01

    Based on current evidence, there is a little agreement on the best timing for after birth umbilical cord clamping. This study was designed to compare the impact of using two different times for cord clamping on hematocrit concentration and Apgar scores of the neonate. Fifty-six healthy full-term vaginally born neonates were allocated to early (10 seconds after delivery) and late (3 minutes after delivery) umbilical cord clamping groups in this randomized clinical trial. We recorded the length of the 3rd stage of labor and Apgar score at 5 minutes. Infant's hematocrit was measured at 2 and 18 hours of age. Neonatal hematocrit differed between the two groups. Late cord clamping group had greater hematocrit at 2 hours (45.5 ± 4 vs. 49.5 ± 4.4, P = 0.0003) and 18 hours (47.7 ± 5.5 vs. 52.9 ± 4.3, P = 0.0002). Apgar scores at 5 minutes (9.3 ± 0.6 vs. 9.4 ± 0.6, p = 0.5) and duration of delivery 3rd stage (10.2 ± 3.7 min vs. 8.9 ± 5 min, P = 0.2) did not differ between early and late cord clamping groups respectively. Late cord clamping leads to a significant increase in the hematocrit of the neonate but it does not have effects on Apgar score and duration of the 3rd stage of labor.

  3. Can selective arterial clamping with fluorescence imaging preserve kidney function during robotic partial nephrectomy?

    Science.gov (United States)

    McClintock, Tyler R; Bjurlin, Marc A; Wysock, James S; Borofsky, Michael S; Marien, Tracy P; Okoro, Chinonyerem; Stifelman, Michael D

    2014-08-01

    To compare renal functional outcomes in robotic partial nephrectomy (RPN) with selective arterial clamping guided by near-infrared fluorescence (NIRF) imaging to a matched cohort of patients who underwent RPN without selective arterial clamping and NIRF imaging. From April 2011 to December 2012, NIRF imaging-enhanced RPN with selective clamping was used in 42 cases. Functional outcomes of successful cases were compared with a cohort of patients, matched by tumor size, preoperative estimated glomerular filtration rate (eGFR), functional kidney status, age, sex, body mass index, and American Society of Anesthesiologists score, who underwent RPN without selective clamping and NIRF imaging. In matched-pair analysis, selective clamping with NIRF was associated with superior kidney function at discharge, as demonstrated by postoperative eGFR (78.2 vs 68.5 mL/min/1.73 m(2); P = .04), absolute reduction of eGFR (-2.5 vs -14.0 mL/min/1.73 m(2); P functional outcomes when compared with RPN without selective arterial clamping and NIRF imaging. With this effect attenuated at later follow-up, randomized prospective studies and long-term assessment of kidney-specific functional outcomes are needed to further assess the benefits of this technology. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. The Formation of the Surface during AN Abrasive Finishing at Constant and Variable Clamping Forces: Finishing at Constant and Variable Clamping Forces

    Science.gov (United States)

    Muratov, Karim Ravilevich; Muratov, Ravil Arifovich; Ablyaz, Timur Rizovich; Gashev, Evgeniy Anatolyevich

    2017-06-01

    In this work the flat abrasive finishing process is reported. The mechanical and chemical phenomena taking place during the finishing process are described. The most common forming process schemes observed during abrasive treatment are reviewed. The schemes of pulsed, geometrical and energetic models are discussed. On the basis of the energetic hypothesis and Preston hypothesis, the rational law of clamping force variation during the finishing is established. This law allowed for the stabilization of the contact pressure and an increase of the treatment efficiency. An exponential dependence of a boundary contact area variation during the finishing of planes with different initial profiles of the macro-topography is developed. An experimental confirmation of the Preston hypothesis during the abrasive finishing is carried out with the plane-finishing machine “Rastr 220”. The comparison experiments are carried out at constant and variable clamping forces of the treated surface towards the tool. It is found that by varying the forces according to the exponential law (i.e. similar to the changing of the boundary contact area during the abrasive finishing) the process efficiency is increasing by a factor of 2.5-3. It is shown that the changes of the root mean square deviation σ of the roughness Ra of a treated surface in the beginning of the process (at time t=1 min) during the finishing at a constant clamping force is two times higher compared to the treatment at a variable clamping force in the same time period.

  5. Optical Design of Spaceborne Low-distortion and Super-wide-angle Aerosol Imager%星载超广角气溶胶探测仪均匀像面性光学设计

    Institute of Scientific and Technical Information of China (English)

    薛庆生

    2012-01-01

    为满足空间遥感的迫切需求,设计了星载低畸变超广角气溶胶探测仪系统.系统中多光谱成像仪的光谱范围为0.860~0.965 μm,全视场角为94°,相对孔径为1∶4,采用反远距结构,系统后工作距离为42 mm.根据反远距结构的像差特点,提出了合理选用易于加工的二次曲面校正畸变,并利用光阑像差产生的有效像差渐晕改善像面照度分布设计方法.运用光学设计软件CODE V和ZEMAX对气溶胶探测仪光学系统进行了光线追迹和优化并对设计结果进行了分析.结果表明,最大畸变为-1.6%,像面上边缘视场的照度大于中心视场照度的46%,光学系统在奈奎斯特频率38.5 lp/mm处的光学传递函数均达到0.59以上,完全满足设计指标要求;体积小,适合空间遥感应用;同时证明了设计方法是可行的.%In order to meet the urgent requirements of space remote sensing, a spaceborne low-distortion and super-wide-angle aerosol imager system is designed. The system is a multi-spectral imager with the working wavelength band from 0. 860 μm to 0. 965 μm, and its full field of view is 94° and the relative aperture is 1 : 4. By using a retrofocus structure, its back working is 42 mm in the optical system. Based on the aberration characteristics of retrofocus structure, methods for correcting distortion and improving the illuminance distribution are proposed. Its distortion is corrected by choosing suitable quadric surface, and the illuminance distribution on image plane is improved by using effective aberration vignetting resulted from stop aberration. Ray tracing, optimization and analysis are performed by CODE V and ZEMAX software. The analysis results demonstrate that the maximum distortion is less than -1. 6% , and the illuminance at edge field of view is higher than that of 46. 9% of central field of view and the MTF is higher than 0. 59 at Nyquist frequency 38. 5 lp/mm, which satisfies the requirement. Its

  6. M. tuberculosis sliding β-clamp does not interact directly with the NAD+-dependent DNA ligase.

    Directory of Open Access Journals (Sweden)

    Vandna Kukshal

    Full Text Available The sliding β-clamp, an important component of the DNA replication and repair machinery, is drawing increasing attention as a therapeutic target. We report the crystal structure of the M. tuberculosis β-clamp (Mtbβ-clamp to 3.0 Å resolution. The protein crystallized in the space group C222(1 with cell-dimensions a = 72.7, b = 234.9 & c = 125.1 Å respectively. Mtbβ-clamp is a dimer, and exhibits head-to-tail association similar to other bacterial clamps. Each monomer folds into three domains with similar structures respectively and associates with its dimeric partner through 6 salt-bridges and about 21 polar interactions. Affinity experiments involving a blunt DNA duplex, primed-DNA and nicked DNA respectively show that Mtbβ-clamp binds specifically to primed DNA about 1.8 times stronger compared to the other two substrates and with an apparent K(d of 300 nM. In bacteria like E. coli, the β-clamp is known to interact with subunits of the clamp loader, NAD(+-dependent DNA ligase (LigA and other partners. We tested the interactions of the Mtbβ-clamp with MtbLigA and the γ-clamp loader subunit through radioactive gel shift assays, size exclusion chromatography, yeast-two hybrid experiments and also functionally. Intriguingly while Mtbβ-clamp interacts in vitro with the γ-clamp loader, it does not interact with MtbLigA unlike in bacteria like E. coli where it does. Modeling studies involving earlier peptide complexes reveal that the peptide-binding site is largely conserved despite lower sequence identity between bacterial clamps. Overall the results suggest that other as-yet-unidentified factors may mediate interactions between the clamp, LigA and DNA in mycobacteria.

  7. Contact angle hysteresis: study by dynamic cycling contact angle measurements and variable angle spectroscopic ellipsometry on polyimide.

    Science.gov (United States)

    Hennig, A; Eichhorn, K-J; Staudinger, U; Sahre, K; Rogalli, M; Stamm, M; Neumann, A W; Grundke, K

    2004-08-03

    The phenomenon of contact angle hysteresis was studied on smooth films of polyimide, a polymer type used in the microelectronic industry, by dynamic cycling contact angle measurements based on axisymmetric drop shape analysis-profile in combination with variable angle spectroscopic ellipsometry (VASE). It was found that both advancing and receding contact angles became smaller with increasing the number of cycles and are, therefore, not a property of the dry solid alone. The changes of the wetting behavior during these dynamic cycling contact angle measurements are attributed mainly to swelling and/or liquid retention. To reveal the water-induced changes of the polymer film, the polyimide surface was studied before and after the contact with a water droplet by VASE. Both the experimental ellipsometric spectrum for Delta and that for Psi as well as the corresponding simulations show characteristic shifts due to the contact with water. The so-called effective medium approximation was applied to recover information about the thickness and effective optical constants of the polymer layer from the ellipsometrically measured values of Delta and Psi. On the basis of these results, the swelling and retention behavior of the polyimide films in contact with water droplets were discussed.

  8. Study & Design on the Manual Clamping Mechanism for A New Style of Fast Dropping Device%一种新型速降装置手动夹紧机构的改进设计与分析

    Institute of Scientific and Technical Information of China (English)

    陶表达

    2011-01-01

    The three-steps reinforcement manual clamping devices is designed for specific working condition.Its structure features and working principles are analyzed.The calculating formulas for the clamping force are gave.The best force-increasing angle range is pointed.The notable features of this clamping device are simple structure, light weight and a very large output clamping force.In addition, it is very easy operation and manufacture.%根据特殊工况,设计一种手动三级增力夹紧机构,分析其工作原理和结构特点,给出夹紧力计算公式,并优化增力角,指出最佳角度工作区间.其显著特点是结构简单、重量轻、夹紧力大、操作方便、制造工艺性好.

  9. PRIMARY OPEN ANGLE GLAUCOMA IN THYROID DISORDER

    Directory of Open Access Journals (Sweden)

    Pragati Garg

    2016-07-01

    Full Text Available PURPOSE To assess the association of thyroid profile with open angle glaucoma. DESIGN Cross-sectional observational study. MATERIAL AND METHOD 128 cases of diagnosed thyroid disorder were enrolled. 5 cases dropped out. Ocular examination included applanation tonometry, stereoscopic optic disc photography, and automated perimetry. Correlative association of thyroid disorder and open angle glaucoma was assessed. RESULTS Of 123 patients of thyroid disorder, 87.8% had hypothyroidism and remaining 12.2% had hyperthyroidism. 15.74% of hypothyroidism and 20% of hyperthyroidism patients had open angle glaucoma, which was statistically significant (Pearson chi-square: Value=6.548, df=2, p=0.040. On multivariate analysis with other risk factors like female sex, family history of glaucoma, myopia, hypertension, and diabetes; it was found that hypothyroidism is an independent risk factor for open angle glaucoma. CONCLUSION All patients having thyroid disorder should be investigated for early diagnosis of open angle glaucoma so that if need be antiglaucoma treatment is started at the earliest and the eye maybe saved from any further deterioration.

  10. Contact angle hysteresis explained.

    Science.gov (United States)

    Gao, Lichao; McCarthy, Thomas J

    2006-07-04

    A view of contact angle hysteresis from the perspectives of the three-phase contact line and of the kinetics of contact line motion is given. Arguments are made that advancing and receding are discrete events that have different activation energies. That hysteresis can be quantified as an activation energy by the changes in interfacial area is argued. That this is an appropriate way of viewing hysteresis is demonstrated with examples.

  11. The lateral angle revisited

    DEFF Research Database (Denmark)

    Morgan, Jeannie; Lynnerup, Niels; Hoppa, R.D.

    2013-01-01

    measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability...... method appears to be of minimal practical use in forensic anthropology and archeology. © 2013 American Academy of Forensic Sciences....

  12. A central swivel point in the RFC clamp loader controls PCNA opening and loading on DNA.

    Science.gov (United States)

    Sakato, Miho; O'Donnell, Mike; Hingorani, Manju M

    2012-02-17

    Replication factor C (RFC) is a five-subunit complex that loads proliferating cell nuclear antigen (PCNA) clamps onto primer-template DNA (ptDNA) during replication. RFC subunits belong to the AAA(+) superfamily, and their ATPase activity drives interactions between the clamp loader, the clamp, and the ptDNA, leading to topologically linked PCNA·ptDNA. We report the kinetics of transient events in Saccharomyces cerevisiae RFC-catalyzed PCNA loading, including ATP-induced RFC activation, PCNA opening, ptDNA binding, ATP hydrolysis, PCNA closing, and PCNA·ptDNA release. This detailed perspective enables assessment of individual RFC-A, RFC-B, RFC-C, RFC-D, and RFC-E subunit functions in the reaction mechanism. Functions have been ascribed to RFC subunits previously based on a steady-state analysis of 'arginine-finger' ATPase mutants; however, pre-steady-state analysis provides a different view. The central subunit RFC-C serves as a critical swivel point in the clamp loader. ATP binding to this subunit initiates RFC activation, and the clamp loader adopts a spiral conformation that stabilizes PCNA in a corresponding open spiral. The importance of RFC subunit response to ATP binding decreases as RFC-C>RFC-D>RFC-B, with RFC-A being unnecessary. RFC-C-dependent activation of RFC also enables ptDNA binding, leading to the formation of the RFC·ATP·PCNA(open)·ptDNA complex. Subsequent ATP hydrolysis leads to complex dissociation, with RFC-D activity contributing the most to rapid ptDNA release. The pivotal role of the RFC-B/C/D subunit ATPase core in clamp loading is consistent with the similar central location of all three ATPase active subunits of the Escherichia coli clamp loader.

  13. Timing of umbilical cord-clamping and infant anaemia: the role of maternal anaemia.

    Science.gov (United States)

    Blouin, Brittany; Penny, Mary E; Maheu-Giroux, Mathieu; Casapía, Martín; Aguilar, Eder; Silva, Hermánn; Creed-Kanashiro, Hilary M; Joseph, Serene A; Gagnon, Anita; Rahme, Elham; Gyorkos, Theresa W

    2013-05-01

    Evidence from randomized controlled trials has shown that delayed cord-clamping is beneficial to infant iron status. The role of maternal anaemia in this relationship, however, has not been established. To determine the effect of maternal anaemia at delivery on the association between timing of umbilical cord-clamping and infant anaemia at 4 and 8 months of age. A cohort of pregnant women admitted to the labour room of Hospital Iquitos (Iquitos, Peru) and their newborns were recruited into the study during two time periods (18 May to 3 June and 6-20 July 2009). Between the two recruitment periods, the hospital's policy changed from early to delayed umbilical cord-clamping. Maternal haemoglobin levels were measured before delivery, and the time between delivery and cord-clamping was recorded at delivery for the entire cohort. Mother-infant pairs were followed-up at 4 (n = 207) and 8 months (n = 184) post partum. Infant haemoglobin levels were measured at follow-up visits. Data were analysed using logistic regression models. The prevalence of maternal anaemia (Hb cord-clamping and infant anaemia was modified by the mother's anaemia status. Significant benefits of delayed cord-clamping in preventing anaemia were found in infants born to anaemic mothers at both 4 months (aOR = 0.59, 95% CI 0.36-0.99) and 8 months (aOR = 0.38, 95% CI 0.19-0.76) of age. The study contributes additional evidence in support of delayed cord-clamping. This intervention is likely to have most public health impact in areas with a high prevalence of anaemia during pregnancy.

  14. Timing of umbilical cord clamping after birth for optimizing placental transfusion.

    Science.gov (United States)

    Raju, Tonse N K

    2013-04-01

    A brief delay in clamping the umbilical cord after birth offers health benefits to the newborn, with no adverse effects to the mother or her infant. Yet, in most obstetric practice, the cord is clamped soon after birth. A summary of the current evidence on delayed cord clamping and some reasons for the disconnect between the evidence and practice are discussed here, along with the recommendations from professional organizations and societies about this practice. In term infants, umbilical cord clamping between 30 and 180 s after birth results in higher concentrations of hemoglobin and hematocrit during the neonatal period, and increased serum ferritin levels and a lower incidence of iron-deficiency anemia at 4-6 months of age. These are important benefits for children in low and middle income countries where iron-deficiency anemia is highly prevalent. In preterm infants, delayed cord clamping for at least 30 s increases the concentrations of hemoglobin and hematocrit, improves mean systemic blood pressure, urine output, and cardiac function, and decreases the need for vasopressors and blood transfusions during the neonatal period. It also decreases the prevalence of necrotizing enterocolitis, sepsis, and intraventricular hemorrhage (all grades). Milking of the unclamped umbilical cord toward the infant soon after birth also has similar beneficial effects. In some studies, more infants in the delayed cord clamping groups required phototherapy for jaundice. Many professional organizations, societies, and experts recommend at least a 30-s delay before clamping the umbilical cord, especially after preterm births. The value of this practice for term births in resource-rich settings has not been evaluated.

  15. Umbilical cord blood acid-base and gas analysis after early versus delayed cord clamping in neonates at term.

    Science.gov (United States)

    De Paco, Catalina; Florido, Jesús; Garrido, Mari Carmen; Prados, Sonia; Navarrete, Luis

    2011-05-01

    To compare umbilical cord acid-base status and blood gas analysis between umbilical cords clamped within 10 s and at 2 min of delivery. A total of 158 healthy full-term mothers were randomly assigned to an early clamping (clamping (2 min post-delivery, n = 79) group. After application of inclusion criteria, umbilical vein blood acid-base status and gases were analyzed in 65 early clamped and 51 delayed clamped cords. Fewer cases could be examined in the umbilical artery: 55 cords in the early clamping group and 44 in the delayed one. Acid-base and gas analysis results did not significantly differ between the groups in the umbilical vein or umbilical artery, with the exception of a higher (p umbilical artery pO(2) value in the delayed versus early clamping group. No significant differences in umbilical vein or artery pCO(2) or HCO(3) (-) values were observed between the early and delayed clamp groups. A delay of 2 min before umbilical cord clamping does not significantly change acid-base and gas analysis results, with the exception of a higher mean umbilical artery pO(2) value in the delayed clamping group.

  16. Analysis of The Clamping Force for 2D Electro-hydraulic Rotary Valve%2D电液转阀式换向阀阀芯卡紧力分析

    Institute of Scientific and Technical Information of China (English)

    童成伟; 阮健; 孔晨菁; 刘奎

    2016-01-01

    Introduces the working principle of 2D electro-hydraulic rotary valve, and puts forward a design scheme of 2D electro-ydraulic rotary valve.Based on the principle of gap flow and analysis of the radial clamping force of the spool of 2D electro-hydraulic rotary valve un-der eccentric conditions,the theoretical calculation formula of the clamping force of the spool is obtained.Using MATLAB software to draw the relationship of spool radial clamping force with eccentric angle and the angle of high and low pressure groove.%介绍了2D电液转阀式换向阀的工作原理,提出了一种2D电液转阀式换向阀的设计方案;应用缝隙流动原理,对2D电液转阀式换向阀阀芯在偏心情况下的径向卡紧力进行系统理论分析,得到阀芯液压卡紧力的理论计算公式;运用MATLAB软件进行数值计算,得出阀芯径向卡紧力与偏心角位置和高低压槽口夹角的关系。

  17. Clampe de Ganz no tratamento de urgência em lesões do anel pélvico Ganz clamps to treat emergencies in pelvic ring lesions

    Directory of Open Access Journals (Sweden)

    Gilberto José Cação Pereira

    2008-07-01

    Full Text Available OBJETIVO: Avaliar a eficiência do clampe de Ganz na estabilização e redução dos deslocamentos da pelve, quando utilizado no tratamento de urgência, além de aquilatar eventuais dificuldades e facilidades do método. MÉTODOS: O clampe de Ganz foi utilizado no tratamento de urgência em 31 pacientes com graves lesões do anel pélvico (Tile C associadas a importante instabilidade hemodinâmica. RESULTADO: Entre os pacientes, 27 (87,1% apresentaram evolução favorável, com estabilização, redução dos deslocamentos e compressão da região posterior do anel, além de estabilização hemodinâmica, e quatro (12,9% evoluíram para óbito. CONCLUSÃO: O clampe de Ganz mostrou-se eficiente ferramenta no tratamento de urgência das lesões do anel pélvico, por ser de concepção simples, de rápida colocação, não impedir ou dificultar procedimentos no abdome e, principalmente, por permitir a estabilização da pelve, redução dos deslocamentos e compressão na região posterior do anel, local onde ocorrem os maiores sangramentos, reduzindo-os ou eliminando-os.OBJECTIVE: To evaluate the effectiveness of Ganz clamp to stabilize and reduce pelvic dislocations in emergency situations, and to assess possible difficult and easy aspects of the method. METHOD: Ganz clamp was used in the emergency treatment of 31 patients with severe lesions of the pelvic ring (Tile C associated to major hemodynamic instability. RESULTS: Among the patients, 27 (87.1% presented a favorable evolution, with stabilization, reduction of dislocations, and compression of the posterior portion of the ring, and also hemodynamic stabilization, and 4 (12.9% died. CONCLUSION: The Ganz clamp was found to be an effective tool in the emergency treatment of pelvic ring lesions because it has an uncomplicated conception, allowing for a fast placement, because it does not prevent nor make it difficult for abdominal procedures, and most of all because it allows for the

  18. A silicon-nanowire memory driven by optical gradient force induced bistability

    Energy Technology Data Exchange (ETDEWEB)

    Dong, B. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), Singapore 117685 (Singapore); Cai, H., E-mail: caih@ime.a-star.edu.sg; Gu, Y. D.; Kwong, D. L. [Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), Singapore 117685 (Singapore); Chin, L. K.; Ng, G. I.; Ser, W. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Huang, J. G. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), Singapore 117685 (Singapore); School of Mechanical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yang, Z. C. [School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China); Liu, A. Q., E-mail: eaqliu@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China)

    2015-12-28

    In this paper, a bistable optical-driven silicon-nanowire memory is demonstrated, which employs ring resonator to generate optical gradient force over a doubly clamped silicon-nanowire. Two stable deformation positions of a doubly clamped silicon-nanowire represent two memory states (“0” and “1”) and can be set/reset by modulating the light intensity (<3 mW) based on the optical force induced bistability. The time response of the optical-driven memory is less than 250 ns. It has applications in the fields of all optical communication, quantum computing, and optomechanical circuits.

  19. Incision Below The Clamp sebagai Modifikasi Teknik Insisi pada Frenektomi untuk Minimalisasi Perdarahan

    Directory of Open Access Journals (Sweden)

    S. Suryono

    2016-10-01

    Full Text Available Latar Belakang. Perlekatan frenulum tinggi berdampak merugikan bagi jaringan periodontal maupun fungsi estetik. Perlekatan tinggi yang terjadi pada labialis superior, menimbulkan gingivitis dan sentral diastema yang menjadikan indikasi untuk dilakukan frenektomi. Frenektomi dengan teknik melakukan insisi di atas dan di bawah clamp berakibat lebarnya luka karena tarikan otot bibir, yang berdampak terjadi banyak perdarahan. Tujuan. Melakukan evaluasi terhadap modifikasi teknik insisi yang diharapkan dapat mengurangi perdarahan. Kasus dan Penanganan. Laporan kasus ini memaparkan penanganan kasus pada perlekatan frenulum tinggi yang diikuti adanya sentral diastema. Pasien dengan diagnosa frenulum tinggi dan indikasi frenektomi dilakukan tindakan preoperasi. Tindakan operasi dilakukan dengan menggunakan pisau bedah, modifikasi insisi (Insision below the Clamp dilakukan dengan cara menempatkan clamp frenulum pada posisi yang berdekatan dan sejajar dengan bibir, tindakan insisi dilakukan di bawah clamp, disusul dengan penjahitan pada area mucolabial fold. Selama operasi dilakukan terlihat luka tidak melebar, tidak banyak darah yang keluar, pasien dan dokter merasa nyaman. Kesimpulan. Insision below the Clamp merupakan modifikasi teknik insisi pada frenektomi yang bisa dilakukan oleh para praktisi untuk meminimalisir perdarahan yang terjadi selama proses pengambilan frenulum dengan menggunakan pisau bedah.   Background. Attachment of high frenulum has negative impact on periodontal tissues as well as an aesthetic function. High attachment of frenulum that occurs in labialis superior, causing gingivitis and central diastema that are indications to do Frenectomy. Conventional techniques of Frenectomy performed with insisions above and below the clamp resulted in wide injury due to muscle contraction, which affects a lot of bleeding. Objective. To evaluate modification insision technique which hopefully can minimize the bleeding. Case and Treatment. This

  20. Relationship between the Angle of Repose and Angle of Internal ...

    African Journals Online (AJOL)

    Keywords: Angle of repose, angle of internal friction, granular materials, triaxial compression ... such a granular material is sharp, making a steep .... study. Therefore, grains had to be condi- tioned to the respective moisture contents by adding ...

  1. Novel Low Loss Active Voltage Clamp Circuit for Series Connection of RCGCT thyristors

    Science.gov (United States)

    Ito, Hiroshi; Suzuki, Akihiro; Iwata, Akihiko

    This paper describes novel low loss active voltage clamp circuits for the series connection of RCGCT thyristors. For high voltage converters the series connection of power semiconductor devices is an essential technique for direct switching of high voltages. Several protection circuits have been applied to the series connection of RCGCT thyristors such as CRD snubber circuits which suppress over-voltages across RCGCT thyristors, and voltage balancing resistors to equalize voltage sharing in steady states. However, significant losses in these protection circuits lower the converter’s efficiency. We propose novel low-loss protection circuits, which have active voltage clamp snubber circuits and static voltage balancing circuits. The clamp capacitor voltage of the active voltage clamp snubber circuits are designed to be higher than the equally divided DC-Link voltage. This method can reduce the loss of the clamp circuit to no more than 1/10 of that of the conventional CRD snubber. Also the static voltage balancing circuits compensate for the voltage imbalance generated by the difference in the leakage current between the series connection RCGCT thyristors.

  2. Gain-clamping techniques in two-stage double-pass L-band EDFA

    Indian Academy of Sciences (India)

    S W harun; N Md Samsuri; H Ahmad

    2006-03-01

    Two designs of long-wavelength band erbium-doped fiber amplifier (L-band EDFA) for gain clamping in double-pass systems are demonstrated and compared. The first design is based on ring laser technique where a backward amplified spontaneous emission (ASE) from the second stage is routed into the feedback loop to create an oscillating laser for gain clamping. The gain is clamped at 18.6 dB from -40 to -8 dBm with a gain variation of less than ± 0.1 dB and a noise figure of less than 6 dB. Another scheme is based on partial reflection of ASE into the EDFA, which is demonstrated using a narrowband fiber Bragg grating. This scheme achieves a good gain clamping characteristic up to -12 dBm of input signal power with a gain variation of less than ± 0.3 dB from a clamped gain of 22 dB. The noise figure of a 1580 nm signal is maintained below 5 dB in this amplifier since this scheme is not based on lasing mechanism. The latter scheme is also expected to be free from the relaxation oscillation problem.

  3. Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes.

    Science.gov (United States)

    McDonald, Susan J; Middleton, Philippa; Dowswell, Therese; Morris, Peter S

    2013-07-11

    Policies for timing of cord clamping vary, with early cord clamping generally carried out in the first 60 seconds after birth, whereas later cord clamping usually involves clamping the umbilical cord more than one minute after the birth or when cord pulsation has ceased. The benefits and potential harms of each policy are debated. To determine the effects of early cord clamping compared with late cord clamping after birth on maternal and neonatal outcomes We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 February 2013). Randomised controlled trials comparing early and late cord clamping. Two review authors independently assessed trial eligibility and quality and extracted data. We included 15 trials involving a total of 3911 women and infant pairs. We judged the trials to have an overall moderate risk of bias. Maternal outcomes: No studies in this review reported on maternal death or on severe maternal morbidity. There were no significant differences between early versus late cord clamping groups for the primary outcome of severe postpartum haemorrhage (risk ratio (RR) 1.04, 95% confidence interval (CI) 0.65 to 1.65; five trials with data for 2066 women with a late clamping event rate (LCER) of ~3.5%, I(2) 0%) or for postpartum haemorrhage of 500 mL or more (RR 1.17 95% CI 0.94 to 1.44; five trials, 2260 women with a LCER of ~12%, I(2) 0%). There were no significant differences between subgroups depending on the use of uterotonic drugs. Mean blood loss was reported in only two trials with data for 1345 women, with no significant differences seen between groups; or for maternal haemoglobin values (mean difference (MD) -0.12 g/dL; 95% CI -0.30 to 0.06, I(2) 0%) at 24 to 72 hours after the birth in three trials. Neonatal outcomes: There were no significant differences between early and late clamping for the primary outcome of neonatal mortality (RR 0.37, 95% CI 0.04 to 3.41, two trials, 381 infants with a LCER of ~1%), or for most other

  4. Delayed Umbilical Cord Blood Clamping: First Line of Defense Against Neonatal and Age-Related Disorders.

    Science.gov (United States)

    Sanberg, Paul R; Divers, Ryan; Mehindru, Anuj; Mehindru, Ankur; Borlongan, Cesar V

    2014-06-01

    The aging body is unable to maintain homeostasis in cell genesis and function. Stem cell-based regenerative medicine may reverse aging and treat age-related disorders. This perspective article discusses the therapeutic effects of stem cell transplantation on neonatal diseases, which may have long-lasting benefits affecting even the aging process. In particular, the article highlights the potential of the earliest transfer of stem cells between a mother and fetus via the umbilical cord during child birth and how this process may modify the clinical practice of umbilical cord clamping. While such umbilical cord clamping is routinely performed in an expeditious manner after birth for stem cell banking, the present article advances the concept that a delay in clamping the umbilical cord may actually allow more stem cells to be delivered from the mother to the fetus. The authors' overarching hypothesis is that early umbilical cord clamping results in an artificial loss of stem cells at birth and increases the infant's susceptibility to both neonatal and age-related diseases, while delaying umbilical cord clamping is perhaps the most effective and non-invasive way to transplant stem cells in order to treat these diseases.

  5. Trail without Catheter after Transurethral Resection of Prostate: Clamp It or Not?

    Directory of Open Access Journals (Sweden)

    Vikash Talreja

    2016-01-01

    Full Text Available Background. There has been argument between clinical practitioners about clamping catheter or not prior to its removal after transurethral resection of prostate (TURP. We conducted a clinical trial to assess whether clamping has any role in early bladder tone recovery particularly in patients who undergo TURP. Methods. Randomized clinical trial was conducted at a tertiary care hospital, Karachi from January 2014 to July 2015. Eighty-six study participants who underwent TURP were randomly allocated into two groups of 43 participants each. In Group I, patient’s Foley catheter was not clamped prior to its removal and in Group II Foley catheter was clamped. Data of all subjects were analyzed using SPSS version 20. Results. There was no significant difference in age and weight of resected tissues between two groups. Among 4 patients in Group I who required recatheterization, 1 patient was discharged with catheter as compared to Group II in which 2 patients were discharged with catheter (P=0.99. Only 1 patient (2.3% in Group II had bleeding which required recatheterization. Length of stay was significantly affected by early and free removal of Foley catheter (P<0.001. Conclusion. The results of current study identified that clamping whether done or not had no significant impact on urinary retention.

  6. Functional dissection of synaptic circuits: in vivo patch-clamp recording in neuroscience

    Directory of Open Access Journals (Sweden)

    Can eTao

    2015-05-01

    Full Text Available Neuronal activity is dominated by synaptic inputs from excitatory or inhibitory neural circuits. With the development of in vivo patch-clamp recording, especially in vivo voltage-clamp recording, researchers can not only directly measure neuronal activity, such as spiking responses or membrane potential dynamics, but also quantify synaptic inputs from excitatory and inhibitory circuits in living animals. This approach enables researchers to directly unravel different synaptic components and to understand their underlying roles in particular brain functions. Combining in vivo patch-clamp recording with other techniques, such as two-photon imaging or optogenetics, can provide even clearer functional dissection of the synaptic contributions of different neurons or nuclei. Here, we summarized current applications and recent research progress using the in vivo patch-clamp recording method and focused on its role in the functional dissection of different synaptic inputs. The key factors of a successful in vivo patch-clamp experiment and possible solutions based on references and our experiences were also discussed.

  7. The Effect of an Added Mass on the Frequency Shifts of a Clamped-Clamped Microbeam for Bio-Mass Detection

    KAUST Repository

    Bouchaala, Adam M.

    2016-12-05

    We present analytical formulations to calculate the induced resonance frequency shifts of electrically actuated clamped-clamped microbeams due to an added mass. Based on the Euler-Bernoulli beam theory, we investigate the linear dynamic responses of the beams added masses, which are modeled as discrete point masses. Analytical expressions based on perturbation techniques and a one-mode Galerkin approximation are developed to calculate accurately the frequency shifts under a DC voltage as a function of the added mass and position. The analytical results are compared to numerical solution of the eigenvalue problem. Results are shown for the fundamental as well as the higher-order modes of the beams. The results indicate a significant increase in the frequency shift, and hence the sensitivity of detection, when scaling down to nano scale and using higher-order modes.

  8. Variable angle correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y K [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  9. Significance of Shrinkage Induced Clamping Pressure in Fiber-Matrix Bonding in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    The present paper accesses the significance of shrinkage inducedclamping pressure in fiber/matrix bonding mechanisms incementitious composite materials. The paper contains a description of an experimental setup whichallows mbox{measurement} of the clamping pressure which develops on anelastic...... acting on any elastic inhomogeneityembedded in the same cementitious matrix material. Fiber-shaped inhomogeneities are of special interest in cementitious composite material systems andresults are presented for the development of clamping pressure on three typical fiber types in two typical cementpastes...... used in high performance cementitious composite materials.Assuming a Coulomb type of friction on the fiber/matrix interface andusing typical values for the frictional coefficient it is shownthat the shrinkage induced clamping pressure could be one of the mostimportant factors determining the frictional...

  10. Development of planar patch clamp technology and its application in the analysis of cellular electrophysiology

    Institute of Scientific and Technical Information of China (English)

    Peihua Chen; Wei Zhang; Jun Zhou; Ping Wang; Lidan Xiao; Mo Yang

    2009-01-01

    A patch clamp chip, as a novel cell-based chip for electrophysiological recordings, has many prominent advantages such as high res-olution, accuracy, high throughput and automation. It can be used to perform multivariate and real-time measurements of cell networks in situ. Therefore, this technology will dramatically promote the research on ionic channels, neuronal networks and the application of this technology in drug screening. This paper reviews the development of planar patch clamp technology and its applications in detail. The latest progress in the research of taste cells electrophysiology and taste transduction is also presented. Finally, this paper analyzes the methodology of neural chips. Based on the current research of our laboratory, the prospective applications of a patch clamp chip in the research of taste sensation and transduction mechanisms at molecular and cellular levels are discussed.

  11. Flange joint system for SRF cavities utilizing high force spring clamps for low particle generation

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-05

    A flange joint system for SRF cavities. The flange joint system includes a set of high force spring clamps that produce high force on the simple flanges of Superconducting Radio Frequency (SRF) cavities to squeeze conventional metallic seals. The system establishes the required vacuum and RF-tight seal with minimum particle contamination to the inside of the cavity assembly. The spring clamps are designed to stay within their elastic range while being forced open enough to mount over the flange pair. Upon release, the clamps have enough force to plastically deform metallic seal surfaces and continue to a new equilibrium sprung dimension where the flanges remain held against one another with enough preload such that normal handling will not break the seal.

  12. Enhancing endogenous stem cells in the newbornvia delayed umbilical cord clamping

    Institute of Scientific and Technical Information of China (English)

    Christopher Lawton; Sandra Acosta; Nate Watson; Chiara Gonzales-Portillo; hTeo Diamandis; Naoki Tajiri; Yuji Kaneko; Paul R. Sanberg; Cesar V. Borlongan

    2015-01-01

    There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal beneifts including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deifciency anemia in term infants. Human umbilical cord blood con-tains signiifcant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it en-hances blood lfow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant’s susceptibility to both neonatal and age-related diseases.

  13. [Focus on placental transfusion for preterm neonates: Delayed cord clamping and/or milking?

    Science.gov (United States)

    Sorin, G; Tosello, B

    2016-11-01

    Anemia of prematurity remains a common complication despite recent advances in perinatal and neonatal medicine. The delayed cord clamping (at least 30seconds as recommended) has several benefits: increased hemoglobin and hematocrit levels at birth, improved initial hemodynamic, decreased incidence of transfusions and intraventricular hemorrhages. When the birth transition is difficult, wait 30seconds before clamping can be impossible. So as not to interfere with the neonatal resuscitation, the "milking" has been proposed as an alternative method to the delayed cord clamping. This is a safe and easy method, which can be done either by an obstetrician or pediatrician with comparable results for the child on his hemodynamic, hematological and neurological status. It still lacks technical information on this method and neurodevelopmental outcomes of these preterm infants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Enhancing endogenous stem cells in the newborn via delayed umbilical cord clamping

    Directory of Open Access Journals (Sweden)

    Christopher Lawton

    2015-01-01

    Full Text Available There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal benefits including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deficiency anemia in term infants. Human umbilical cord blood contains significant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it enhances blood flow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant′s susceptibility to both neonatal and age-related diseases.

  15. Enhancing endogenous stem cells in the newborn via delayed umbilical cord clamping.

    Science.gov (United States)

    Lawton, Christopher; Acosta, Sandra; Watson, Nate; Gonzales-Portillo, Chiara; Diamandis, Theo; Tajiri, Naoki; Kaneko, Yuji; Sanberg, Paul R; Borlongan, Cesar V

    2015-09-01

    There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal benefits including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deficiency anemia in term infants. Human umbilical cord blood contains significant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it enhances blood flow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant's susceptibility to both neonatal and age-related diseases.

  16. Sequential dissection of multiple ionic currents in single cardiac myocytes under action potential-clamp.

    Science.gov (United States)

    Banyasz, Tamas; Horvath, Balazs; Jian, Zhong; Izu, Leighton T; Chen-Izu, Ye

    2011-03-01

    The cardiac action potential (AP) is shaped by myriad ionic currents. In this study, we develop an innovative AP-clamp Sequential Dissection technique to enable the recording of multiple ionic currents in the single cell under AP-clamp. This new technique presents a significant step beyond the traditional way of recording only one current in any one cell. The ability to measure many currents in a single cell has revealed two hitherto unknown characteristics of the ionic currents in cardiac cells: coordination of currents within a cell and large variation of currents between cells. Hence, the AP-clamp Sequential Dissection method provides a unique and powerful tool for studying individual cell electrophysiology.

  17. FUNDAMENTAL RESONANCE AND BIFURCATION OF LARGE GENERATOR END WINDING WHEN ITS CLAMPING PLATES ARE LOOSE

    Institute of Scientific and Technical Information of China (English)

    HU Yu-da; QIU Jia-jun; TA Na

    2005-01-01

    Vibration problems of a segment of winding between two clamping plates are studied when the clamping plates, which are used to fix stator end winding, are loose. First,magnetic induction expressions of the winding while the generator was running were given by using separation of variables method. Also, the expressions of the winding electromagnetic force and dry friction force between loosing clamping plates were gotten. Secondly, a mechanical model, which was used to study nonlinear vibration problem of the winding, was set up. Fundamental resonance was analyzed by using multiple scales method, and a resonance equation of amplitude and frequency in steady state was given. Then stability,bifurcation and singularity of the steady solution were studied. Criterions of stability and transition set of the bifurcation equation were obtained. At last, through numerical calculations, resonance curves were obtained. The results are helpful for analysis and protection of generator accidents.

  18. Minimum Normal Force Principle Based Quantitive Optimizationof Clamping Forces for Thin Walled Part

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fa-ping; SUN Hou-fang; SHAHID I.Butt

    2008-01-01

    Based on the stability criteria of workpiece-fixture system, quantitative optimization of clamping forces during precise machining process for thin walled part is studied considering the contact condition between wokpiece and locator, the contact mechanical model is achieved ,which is further been used to calculate the entire passive forces acting on the statically undetermined workpiece by means of the force screw theory as well as minimum norm force principle. Furthermore, a new methodology to optimize clamping forces is put forward, on the criteria of keeping the stability of workpiece during cutting process. By this way, the intensity of clamping forces is decreased dramatically, which will be most beneficial for improving the machining quality of thin-walled parts. Finally, a case study is used to support and validate the proposed model.

  19. Comparison of herniorrhaphy versus clamping of umbilical hernias in horses: a retrospective study of 93 cases (1982-1994).

    OpenAIRE

    1996-01-01

    Many uncomplicated umbilical hernias have been managed successfully in foals by the application of a hernia clamp. Isolated reports of complications following clamp application have led some authors to suggest that it is an unsuitable method of treatment. Little information has been published comparing the complication rates associated with the use of hernia clamps and herniorrhaphy in the treatment of umbilical hernias. The purpose of this retrospective study was to report the characteristic...

  20. [Delayed umbilical cord clamping in preterm infants born before 37 weeks of gestation: A prospective observational study].

    Science.gov (United States)

    Dicky, O; Ehlinger, V; Guyard-Boileau, B; Assouline, C; Arnaud, C; Casper, C

    2017-02-01

    Many international studies have demonstrated that delayed umbilical cord clamping reduces neonatal morbidity. However, in France, delayed umbilical cord clamping is still not performed in many neonatal units. The aims of this study were to evaluate the feasibility of developing a protocol of delayed umbilical cord clamping in the maternity ward of the Toulouse university hospital and to evaluate the impact of this new protocol on neonatal mortality. We conducted a prospective observational study including 123 preterm infants born before 37 weeks of gestation between June 2012 and June 2013 and hospitalized at birth. Delayed cord clamping was performed for at least 30s after birth; otherwise, it was evaluated as early cord clamping. We excluded twin-to-twin transfusion syndrome, congenital abnormalities, alloimmunization, and perinatal asphyxia. We analyzed the reasons why delayed umbilical cord clamping was not performed and then neonatal morbidity in our population. Delayed umbilical cord clamping was performed on 79 infants and 44 infants had early umbilical cord clamping. The two groups had similar baseline characteristics. Preterm infants in the delayed cord-clamping group had a higher level of hemoglobin during the first 24h of life (17.9g/dL versus 16.6g/dL, P=0.005), fewer of them required transfusion (14% versus 35%, P=0.03), and fewer presented late-onset sepsis (8% versus 26%, P=0.02) or bronchopulmonary dysplasia (9% versus 26%, P=0.03). There was no statistically significant increase of hyperbilirubinemia requiring phototherapy. Implanting a new protocol of delayed umbilical cord clamping in our maternity ward proved to be possible without difficulty. The advantages of delayed umbilical cord clamping were observed in this prospective study. Today, delayed cord clamping has become a common practice in our maternity unit. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  1. Modified Blalock clamp: a single-hand autostatic device for pulmonary vessel occlusion during lung cancer resection

    OpenAIRE

    Petrella, Francesco; Solli, Piergiorgio; Borri, Alessandro; Spaggiari, Lorenzo

    2011-01-01

    Vascular clamping during lung cancer resection may be difficult in patients with short vessels or large neoplasms preventing adequate and safe exposure. In addition, the physiological vicinity of some vessels to rigid structures like the bronchi may interfere with ideal clamp positioning even in ordinary procedures. We have modified the original Blalock clamp to facilitate the control of pulmonary vessels and physiologically compress the vessel walls, thereby allowing optimal vascular resecti...

  2. Belt Clamping Device for Flat Screen Magnet Printing Machine%平网磁棒印花机导带压紧装置

    Institute of Scientific and Technical Information of China (English)

    朱红军; 寇恒梅

    2013-01-01

    本文阐述了一种平网磁棒印花机导带压紧装置,它置于版框架上,包括旋合式上下离合套、螺纹座、联接杆、压缩弹簧、导向块、导带压块、橡胶套、长螺杆及版框架。当版框架下降时,导带压块通过压缩弹簧的反作用力即可牢牢压住导带,防止导带位移而造成花型错位。当需要版框落下对花型时,只需旋转离合套一角度,便能快捷地抬离导带压块,实现了版框落下对花的问题。%This paper describes belt clamping device for flat screen magnet printing machine, which is placed on the frame version, including the upper and lower clutch set screw type, thread blocks, connecting rods, compression springs, guide block, the conduction band clamps, rubber sleeve long screw and a version of the framework. When a version of the framework falls, the conduction band of the reaction force of the compression spring clamps to firmly hold the conduction band, prevent displacement of the conduction band pattern caused dislocation. When you need to fall on the flower box version, just rotate the clutch cover an angle, we will be able to lift off the fast conduction band briquetting and achieve edition box fall on the registration issue.

  3. Off-Angle Iris Correction Methods

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Thompson, Joseph T [ORNL; Karakaya, Mahmut [ORNL; Boehnen, Chris Bensing [ORNL

    2016-01-01

    In many real world iris recognition systems obtaining consistent frontal images is problematic do to inexperienced or uncooperative users, untrained operators, or distracting environments. As a result many collected images are unusable by modern iris matchers. In this chapter we present four methods for correcting off-angle iris images to appear frontal which makes them compatible with existing iris matchers. The methods include an affine correction, a retraced model of the human eye, measured displacements, and a genetic algorithm optimized correction. The affine correction represents a simple way to create an iris image that appears frontal but it does not account for refractive distortions of the cornea. The other method account for refraction. The retraced model simulates the optical properties of the cornea. The other two methods are data driven. The first uses optical flow to measure the displacements of the iris texture when compared to frontal images of the same subject. The second uses a genetic algorithm to learn a mapping that optimizes the Hamming Distance scores between off-angle and frontal images. In this paper we hypothesize that the biological model presented in our earlier work does not adequately account for all variations in eye anatomy and therefore the two data-driven approaches should yield better performance. Results are presented using the commercial VeriEye matcher that show that the genetic algorithm method clearly improves over prior work and makes iris recognition possible up to 50 degrees off-angle.

  4. Can robots patch-clamp as well as humans? Characterization of a novel sodium channel mutation.

    Science.gov (United States)

    Estacion, M; Choi, J S; Eastman, E M; Lin, Z; Li, Y; Tyrrell, L; Yang, Y; Dib-Hajj, S D; Waxman, S G

    2010-06-01

    Ion channel missense mutations cause disorders of excitability by changing channel biophysical properties. As an increasing number of new naturally occurring mutations have been identified, and the number of other mutations produced by molecular approaches such as in situ mutagenesis has increased, the need for functional analysis by patch-clamp has become rate limiting. Here we compare a patch-clamp robot using planar-chip technology with human patch-clamp in a functional assessment of a previously undescribed Nav1.7 sodium channel mutation, S211P, which causes erythromelalgia. This robotic patch-clamp device can increase throughput (the number of cells analysed per day) by 3- to 10-fold. Both modes of analysis show that the mutation hyperpolarizes activation voltage dependence (8 mV by manual profiling, 11 mV by robotic profiling), alters steady-state fast inactivation so that it requires an additional Boltzmann function for a second fraction of total current (approximately 20% manual, approximately 40% robotic), and enhances slow inactivation (hyperpolarizing shift--15 mV by human,--13 mV robotic). Manual patch-clamping demonstrated slower deactivation and enhanced (approximately 2-fold) ramp response for the mutant channel while robotic recording did not, possibly due to increased temperature and reduced signal-to-noise ratio on the robotic platform. If robotic profiling is used to screen ion channel mutations, we recommend that each measurement or protocol be validated by initial comparison to manual recording. With this caveat, we suggest that, if results are interpreted cautiously, robotic patch-clamp can be used with supervision and subsequent confirmation from human physiologists to facilitate the initial profiling of a variety of electrophysiological parameters of ion channel mutations.

  5. Umbilical blood flow patterns directly after birth before delayed cord clamping.

    Science.gov (United States)

    Boere, I; Roest, A A W; Wallace, E; Ten Harkel, A D J; Haak, M C; Morley, C J; Hooper, S B; te Pas, A B

    2015-03-01

    Delayed umbilical cord clamping (DCC) affects the cardiopulmonary transition and blood volume in neonates immediately after birth. However, little is known of blood flow in the umbilical vessels immediately after birth during DCC. The objective is to describe the duration and patterns of blood flow through the umbilical vessels during DCC. Arterial and venous umbilical blood flow was measured during DCC using Doppler ultrasound in uncomplicated term vaginal deliveries. Immediately after birth, the probe was placed in the middle of the umbilical cord, pattern and duration of flow in vein and arteries were evaluated until cord clamping. Thirty infants were studied. Venous flow: In 10% no flow was present, in 57% flow stopped at 4:34 (3:03-7:31) (median (IQR) min:sec) after birth, before the cord was clamped. In 33%, flow continued until cord clamping at 5:13 (2:56-9:15) min:sec. Initially, venous flow was intermittent, increasing markedly during large breaths or stopping and reversing during crying, but then became continuous. Arterial flow: In 17% no flow was present, in 40% flow stopped at 4:22 (2:29-7:17) min:sec, while cord pulsations were still palpable. In 43% flow continued until the cord was clamped at 5:16 (3:32-10:10) min:sec. Arterial flow was pulsatile, unidirectional towards placenta or bidirectional to/from placenta. In 40% flow became continuous towards placenta later on. During delayed umbilical cord clamping, venous and arterial umbilical flow occurs for longer than previously described. Net placental transfusion is probably the result of several factors of which breathing could play a major role. Umbilical flow is unrelated to cessation of pulsations. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  6. Alternative positions for the baby at birth before clamping the umbilical cord.

    Science.gov (United States)

    Airey, Rebecca J; Farrar, Diane; Duley, Lelia

    2010-10-06

    The third stage of labour is from birth of the baby until delivery of the placenta. Clamping the umbilical cord is one component of active management of the third stage. Deferring cord clamping allows blood flow between the baby and the placenta to continue; net transfer to the baby is called placental transfusion. If the cord is clamped immediately placental transfusion is restricted. Gravity is one of several factors that may influence the volume and duration of placental transfusion at both vaginal and caesarean births. Hence raising or lowering the baby whilst the cord is intact may influence placental transfusion, which in turn may affect outcome for the baby and the woman. To compare the effects of alternative positions for the baby between birth and cord clamping on outcome for the baby, outcome for the mother and on use of health service resources. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010). Randomised trials comparing alternative positions for the baby at vaginal and caesarean birth, before clamping of the umbilical cord. We independently assessed trial eligibility and quality. When necessary, we contacted study authors for additional information. Thirty-seven studies (7559 mother-infant pairs) were excluded: 33 (7296) because they did not compare alternative positions for the baby before clamping the umbilical cord and four (263) due to quasi-random allocation. No studies met the inclusion criteria. One additional trial is ongoing. No randomised trials have assessed the influence of gravity on placental transfusion. Large, well-designed randomised trials are needed to assess whether gravity influences placental transfusion at vaginal and caesarean births and, if so, whether this affects short-term and long-term outcome for the baby and for the mother.

  7. Design and fabrication of a planar patch-clamp substrate using a silicon-on-insulator wafer

    Science.gov (United States)

    Zhenlong, Zhang; Xiangyang, Liu; Yanli, Mao

    2009-09-01

    The planar patch-clamp technique has been applied to high throughput screening in drug discovery. The key feature of this technique is the fabrication of a planar patch-clamp substrate using appropriate materials. In this study, a planar patch-clamp substrate was designed and fabricated using a silicon-on-insulator (SOI) wafer. The access resistance and capacitance of SOI-based planar patch-clamp substrates are smaller than those of bulk silicon-based planar substrates, which will reduce the distributed RC noise.

  8. ILC Extraction Line for 14 mrad Crossing Angle

    Energy Technology Data Exchange (ETDEWEB)

    Nosochkov, Y.; Markiewicz, T.; Maruyama, T.; Seryi, A.; /SLAC; Parker, B.; /Brookhaven

    2005-12-08

    The earlier studies of the ILC extraction line for 20 mrad and 2 mrad crossing angle options [1]-[5] showed that the 20 mrad design has an advantage of a simpler beamline and lower extraction beam loss because of the independent incoming and extraction optics. However, the large 20 mrad crossing angle requires the use of a crab cavity correction, increases synchrotron radiation emittance growth in the solenoid, and increases photon backscattering from the forward calorimeter of the detector. To reduce these effects, an attempt has been made to minimize the crossing angle while keeping the extraction and incoming lines separate. A new quadrupole scheme near the interaction point has been proposed which allows a reduction of the crossing angle to 14 mrad [6]. The optics design and results of tracking and background simulations for the 14 mrad extraction line are presented.

  9. Design and test of clamping finger-chain type device for recycling agricultural plastic film%夹指链式残膜回收装置的设计及试验

    Institute of Scientific and Technical Information of China (English)

    段文献; 王吉奎; 李阳; 龚贺贺; 牛海龙; 罗威; 毕新胜

    2016-01-01

    The domestic equipment for recycling agricultural plastic film has the problems of low recovery rate of plastic film, wrapping the film collecting parts by plastics, or difficulty of separating the straw and soil from the film. In addition, film removing for the current methods is poor and high impurity content of recovered plastic film can’t be recycled. In order to solve these problems, the clamping finger-chain type device for recycling agricultural plastic film was designed. The designed device mainly consisted of film collecting device, film removing device, transmission system, side film shoveling, tie rod, transverse beam, residual film box, etc. The film collecting device mainly included film collecting frame, upper film collecting sprocket, under film collecting sprocket, film collecting chain, clamping finger, film cutting saw disk, supporting chain roller, tightening devices, etc. The film removing device mainly included film removing rotation shaft, film removing blade, driving sprocket, film removing bracket, bearing chock, etc. The film collecting device was driven by the ground wheel through the film collecting transmission system and the film removing device was driven by the tractor power output shaft through the film removing transmission. Through the design and mechanical analysis of the clamping finger-chain, the structure size parameters of it were determined, which contained the spacing between two clamping finger-chains was 220 mm, and its working angle was 40°, the effective length of clamping fingerL was 135 mm, and the angle between clamping finger and outer link was 20°. The tension mechanism could make the clamping finger-chain be always in a state of tension in the process of operation. The specification parameters of the selected spring were determined by analysis of the tensioning mechanism. Through the structure size design and motion analysis of film removing device, the film removing blade size was determined, and the length

  10. Clamping drainage is unnecessary after minimally invasive total knee arthroplasty in patients with tranexamic acid

    Science.gov (United States)

    Wu, Yuangang; Yang, Timin; Zeng, Yi; Li, Canfeng; Shen, Bin; Pei, Fuxing

    2017-01-01

    Abstract Background: Drainage and tranexamic acid (TXA) have been widely used in total knee arthroplasty (TKA). However, it remains unclear whether it is necessary to clamp the drain after minimally invasive TKA (MIS-TKA) when TXA is used. We therefore conducted a randomized controlled trial to compare the effects of clamping versus not clamping drainage following MIS-TKA in patients in whom TXA was used. Methods: From January 2015 to December 2015, 121 patients undergoing unilateral primary MIS-TKA were enrolled and randomly divided into 2 groups. In the clamping group (N = 60), drainage was clamped for the 1st 4 postoperative hours. In the nonclamping group (N = 61), drainage was not clamped. All patients underwent a minimidvastus approach and received 10 mg/kg TXA intravenously before tourniquet deflation. We recorded the total blood loss, drainage volume, and transfusion requirements in the postoperative period. We also measured the hemoglobin (Hb) and hematocrit (Hct) levels on postoperative days 1, 3, and 5. Other factors, including range of motion (ROM), visual analog scale (VAS), and occurrence of wound-related complications, deep vein thrombosis (DVT), and pulmonary embolism (PE) were recorded at the time of discharge and 1 and 6 months postoperatively. No statistically significant differences were found between the 2 groups with regard to age, gender, weight, BMI, preoperative Hb and Hct levels, preoperative ROM, VAS, duration of surgery, anesthesia method, and the American Society of Anesthesiologists classification. Results: The clamping group experienced better drainage volume results than the nonclamping group (P < 0.001). There were no statistically significant differences in TBL and transfusion requirements (P = 0.105 and 0.276, respectively); Hb and Hct levels on postoperative days 1, 3, and 5 were similar between the 2 groups. No significant differences were found for ROM, VAS, DVT, PE, wound-related complications, and hospital

  11. In vivo patch clamp recording technique in the study of neurophysiology

    Institute of Scientific and Technical Information of China (English)

    Lan-Wei CUI; Yu-Rong LI

    2006-01-01

    The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaesthesia ( or awake) animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivoin order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique have already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.

  12. Cerebral oxygenation and processed EEG response to clamping and shunting during carotid endarterectomy under general anesthesia.

    Science.gov (United States)

    Perez, William; Dukatz, Christopher; El-Dalati, Sami; Duncan, James; Abdel-Rasoul, Mahmoud; Springer, Andrew; Go, Michael R; Dzwonczyk, Roger

    2015-12-01

    Clamping and shunting during carotid endarterectomy (CEA) surgery causes changes in cerebral blood flow. The purpose of this study was to assess and compare, side by side, the cerebral oxygenation (rSO2) and processed electroencephalogram (EEG) response bilaterally to carotid artery clamping and shunting in patients undergoing CEA under general anesthesia. With institutional approval and written informed consent, patients undergoing CEA under general anesthesia and routine carotid artery shunting were recorded bilaterally, simultaneously and continuously with an rSO2 and processed EEG monitor. The response of the monitors during carotid artery clamping and shunting were assessed and compared between monitors and bilaterally within each monitor. Sixty-nine patients were included in the study. At clamping the surgical-side and contralateral-side rSO2 dropped significantly below the baseline incision value (-17.6 and -9.4% respectively). After shunting, the contralateral-side rSO2 returned to baseline while the surgical-side rSO2 remained significantly below baseline (-9.0%) until the shunt was removed following surgery. At clamping the surgical-side and contralateral-side processed EEG also dropped below baseline (-19.9 and -20.6% respectively). However, following shunt activation, the processed EEG returned bilaterally to baseline. During the course of this research, we found the rSO2 monitor to be clinically more robust (4.4% failure rate) than the processed EEG monitor (20.0% failure rate). There was no correlation between the rSO2 or processed EEG changes that occurred immediately after clamping and the degree of surgical side stenosis measured pre-operatively. Both rSO2 and processed EEG respond to clamping and shunting during CEA. Cerebral oximetry discriminates between the surgical and contralateral side during surgery. The rSO2 monitor is more reliable in the real-world clinical setting. Future studies should focus on developing algorithms based on these

  13. Discussion on compact mechanism of air-stream and synchro-formed clamp plate impact molding

    Directory of Open Access Journals (Sweden)

    Zhenling WANG

    2004-11-01

    Full Text Available Applying the air impact molding method to mold the complicated pattern with wider opening surface and deeper concave, there always exist vaulted phenomenon and lower compactibility of sand mold over the entrance and the concave regions. Using the air-stream and synchro-formed clamp plate impact molding, however, this problem will be preferably solved. In this paper, the compact mechanism of the new molding method and the effect of some configuration factors, such as the area flowed by compressed air and the highness of the protruding block displacement around the diffluent clamp plate, on the compactibility of sand mold were discussed.

  14. Experience of application of clamp-on cross-correlation flow meter in nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Gurevich, Y. [Daystar Technology Inc., Ontario (Canada); Ton, V.; Kotenyov, S.; Zhao, C. [Ontario Power Generation, Ontario (Canada); Sharp, B.; Lopez, A. [Advanced Measurements and Analysis Group Inc., Ontario (Canada)

    2010-07-01

    The cross-correlation clamp-on flow meter, CROSSFLOW, developed and manufactured by AMAG, has been used over the world for over 15 years for flow measurements in various systems in nuclear and fossil power plants. Prior that, OPG has used similar technology in Canadian nuclear power plants since 1980-ies. Two recent examples of the application of the clamp-on cross-correlation technology are presented in this paper. In first example OPG meter was used to verify accuracy of ASME nozzles installed in condensate flow lines. In second example AMAG meter was used to measure Diesel Cooling Water (DCW). (author)

  15. Comparison of the cascadability of conventional and gain-clamped semiconductor optical amplifier gates in multi wavelength optical networks

    DEFF Research Database (Denmark)

    Wolfson, David; Stubkjær, Kristian Elmholdt

    1999-01-01

    A detailed investigation of the cascadability of Gc-soaS AND soaS in EDM networks is presented. The analysis shows far superior cascadability of GC-SOAs at a channel bit rate of 2,5 Gbit/s in systems with up to at least 16 channels.......A detailed investigation of the cascadability of Gc-soaS AND soaS in EDM networks is presented. The analysis shows far superior cascadability of GC-SOAs at a channel bit rate of 2,5 Gbit/s in systems with up to at least 16 channels....

  16. Prism Window for Optical Alignment

    Science.gov (United States)

    Tang, Hong

    2008-01-01

    A prism window has been devised for use, with an autocollimator, in aligning optical components that are (1) required to be oriented parallel to each other and/or at a specified angle of incidence with respect to a common optical path and (2) mounted at different positions along the common optical path. The prism window can also be used to align a single optical component at a specified angle of incidence. Prism windows could be generally useful for orienting optical components in manufacture of optical instruments. "Prism window" denotes an application-specific unit comprising two beam-splitter windows that are bonded together at an angle chosen to obtain the specified angle of incidence.

  17. Equilibrium contact angle or the most-stable contact angle?

    Science.gov (United States)

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

    2014-04-01

    It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation.

  18. 频域眼前段光学相干断层扫描对周边虹膜切除术前后前房角的研究%Evaluation of the anterior chamber angle before and after iridectomy by spectral domain-anterior segment optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    袁永刚; 梁纳; 马胜生; 郑东健

    2014-01-01

    目的 应用频域眼前段光学相干断层扫描(OCT)分析周边虹膜切除术前后前房角的变化.方法 原发性前房角关闭者32例(40只眼)行周边虹膜切除术,术前、术后2d、2个月使用频域眼前段OCT进行前房角测量,比较500 μm/750 μm前房角角度(ACA500/ACA750)和500 μm/750μm前房角开放距离(AOD500/AOD750)等指标.结果 各指标在术前、术后差异有统计学意义,术后2d、2个月相应指标差异无统计学意义.结论 原发性前房角关闭行周边虹膜切除术后前房角增宽,可缓解瞳孔阻滞,预防前房角进一步关闭,频域眼前段OCT可进行术前术后的非接触检查,实现前房的生物统计学测量.%Objective To evaluate the change of the anterior chamber angle before and after iridectomy by spectral domain-anterior segment optical coherence tomography(SD-AS OCT).Methods The clinical trial was carried out in 40 eyes of 32 cases with primary angle closure(PAC).500μm/750μm anterior chamber angle (ACA500/ACA750) and 500μm/750μm angle opening distance (AOD500/AOD750) were imaged with SD-AS OCT before and after iridectomy.Results There were statistical significant differences between preoperation and post-operation in ACAS00/ACA750 and AODS00/AOD750.No significant differences of above indexes were found between 2 days and 2 months after surgery.Conclusion The anterior chamber angle becomes wider in PAC patient after iridectomy.This improvement can relieve pupil block and prevent further chamber angle closure.SD-AS OCT can be used to carry out a noncontact biometrical measurement of anterior chamber before and after surgery.

  19. DESIGN OF ILC EXTRACTION LINE FOR 20 MRAD CROSSING ANGLE

    Energy Technology Data Exchange (ETDEWEB)

    Nosochkov, Y.; Moffeit, K.; Seryi, A.; Woods, M.; /SLAC; Arnold, R.; /Massachusetts U., Amherst; Oliver, W.; /Tufts U.; Parker, B.; /Brookhaven; Torrence, E.; /Oregon U.

    2005-05-16

    One of the two ILC Interaction Regions will have a large horizontal crossing angle which would allow to extract the spent beams in a separate beam line. In this paper, the extraction line design for 20 mrad crossing angle is presented. This beam line transports the primary e{sup +}/e{sup -} and beamstrahlung photon beams from the IP to a common dump, and includes diagnostic section for energy and polarization measurements. The optics is designed for a large energy acceptance to minimize losses in the low energy tail of the disrupted beam. The extraction optics, diagnostic instrumentation and particle tracking simulations are described.

  20. Research advances on multifocal electroretinogram in primary open angle glaucoma

    Directory of Open Access Journals (Sweden)

    Feng-Fei Mo

    2013-10-01

    Full Text Available Primary open angle glaucoma is a chronic and progressive optic neuropathy. It can lead to serious damage of visual impairment, and it is an important eye disease of blindness. Multifocal electroretinogram is a new way to measure visual electrophysiology. It can measure electroretinogram of the whole visual field of many small parts in a relatively short period of time, and it can reflect the function of regional retina. It has an extremely important value for early diagnosis of primary open angle glaucoma. The research advances on multifocal electroretinogram in diagnosing primary open angle glaucoma were summarized in this paper.

  1. Performance analysis of CO2 laser polished angled ribbon fiber

    Science.gov (United States)

    Sohn, Ik-Bu; Choi, Hun-Kook; Noh, Young-Chul; Lee, Man-Seop; Oh, Jin-Kyoung; Kim, Seong-min; Ahsan, Md. Shamim

    2017-01-01

    This paper demonstrates CO2 laser assisted simultaneous polishing of angled ribbon fibers consisting eight set of optical fibers. The ribbon fibers were rotated vertically at an angle of 12° and polished by repetitive irradiation of CO2 laser beam at the end faces of the fibers. Compared to mechanically polished sharp edged angled fibers, CO2 laser polishing forms curve edged angled fibers. Increase in the curvature of the end faces of the ribbon fibers causes the increase of the fibers' strength, which in turn represents great robustness against fiber connections with other devices. The CO2 laser polished angled fibers have great smoothness throughout the polished area. The smoothness of the fiber end faces have been controlled by varying the number of laser irradiation. After CO2 laser polishing, the average value of the fiber angle of the ribbon fibers is ∼8.28°. The laser polished ribbon fibers show low insertion and return losses when connecting with commercial optical communication devices. The proposed technique of polishing the angled ribbon fibers is highly replicable and reliable and thus suitable for commercial applications.

  2. Construction, Calibration, and Validation of a Simple Patch-Clamp Amplifier for Physiology Education

    Science.gov (United States)

    Rouzrokh, Ali; Ebrahimi, Soltan Ahmed; Mahmoudian, Massoud

    2009-01-01

    A modular patch-clamp amplifier was constructed based on the Strickholm design, which was initially published in 1995. Various parts of the amplifier such as the power supply, input circuit, headstage, feedback circuit, output and nulling circuits were redesigned to use recent software advances and fabricated using the common lithographic printed…

  3. Five-Level Active-Neutral-Point-Clamped DC/DC Converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Chen, Zhe

    Multi-level converters are getting more and more attentions because of their obvious merits such as lower voltage stress and harmonic, smaller size of output filters, and so on. In this paper, a five-level active-neutral-point-clamped (5L-ANPC) dc/dc converter is proposed for power transfer...

  4. A bulldog clamp that was forgotten during a coronary artery bypass operation 8 years ago

    Science.gov (United States)

    Celkan, Mehmet Adnan; Bayatli, Kivanc

    2012-01-01

    Prevention of retained foreign bodies in the pericardial cavity is critical for patient safety. We report a patient with a bulldog clamp that was forgotten during a coronary artery bypass operation 8 years ago, which was detected by chance and removed. PMID:22815324

  5. A Single-Strand Annealing Protein Clamps DNA to Detect and Secure Homology.

    Directory of Open Access Journals (Sweden)

    Marcel Ander

    2015-08-01

    Full Text Available Repair of DNA breaks by single-strand annealing (SSA is a major mechanism for the maintenance of genomic integrity. SSA is promoted by proteins (single-strand-annealing proteins [SSAPs], such as eukaryotic RAD52 and λ phage Redβ. These proteins use a short single-stranded region to find sequence identity and initiate homologous recombination. However, it is unclear how SSAPs detect homology and catalyze annealing. Using single-molecule experiments, we provide evidence that homology is recognized by Redβ monomers that weakly hold single DNA strands together. Once annealing begins, dimerization of Redβ clamps the double-stranded region and nucleates nucleoprotein filament growth. In this manner, DNA clamping ensures and secures a successful detection for DNA sequence homology. The clamp is characterized by a structural change of Redβ and a remarkable stability against force up to 200 pN. Our findings not only present a detailed explanation for SSAP action but also identify the DNA clamp as a very stable, noncovalent, DNA-protein interaction.

  6. Critical clamp loader processing by an essential AAA+ protease in Caulobacter crescentus.

    Science.gov (United States)

    Vass, Robert H; Chien, Peter

    2013-11-01

    Chromosome replication relies on sliding clamps that are loaded by energy-dependent complexes. In Escherichia coli, the ATP-binding clamp loader subunit DnaX exists as both long (τ) and short (γ) forms generated through programmed translational frameshifting, but the need for both forms is unclear. Here, we show that in Caulobacter crescentus, DnaX isoforms are unexpectedly generated through partial proteolysis by the AAA+ protease casein lytic proteinase (Clp) XP. We find that the normally processive ClpXP protease partially degrades DnaX to produce stable fragments upon encountering a glycine-rich region adjacent to a structured domain. Increasing the sequence complexity of this region prevents partial proteolysis and generates a τ-only form of DnaX in vivo that is unable to support viability on its own. Growth is restored when γ is provided in trans, but these strains are more sensitive to DNA damage compared with strains that can generate γ through proteolysis. Our work reveals an unexpected mode of partial processing by the ClpXP protease to generate DnaX isoforms, demonstrates that both τ and γ forms of DnaX are required for Caulobacter viability, and identifies a role for clamp loader diversity in responding to DNA damage. The conservation of distinct DnaX isoforms throughout bacteria despite fundamentally different mechanisms for producing them suggests there may be a conserved need for alternate clamp loader complexes during DNA damaging conditions.

  7. Characterization of a patch-clamp microchannel array towards neuronal networks analysis

    DEFF Research Database (Denmark)

    Alberti, Massimo; Snakenborg, Detlef; Lopacinska, Joanna M.

    2010-01-01

    for simultaneous patch clamping of cultured cells or neurons in the same network. A disposable silicon/silicon dioxide (Si/SiO2) chip with a microhole array was integrated in a microfluidic system for cell handling, perfusion and electrical recording. Fluidic characterization showed that our PC mu CA can work...

  8. The Response Clamp: Functional characterization of neural systems using closed-loop control

    Directory of Open Access Journals (Sweden)

    Avner eWallach

    2013-01-01

    Full Text Available The voltage clamp method, pioneered by Hodgkin, Huxley and Katz, laid the foundations to neurophysiological research. Its core rationale is the use of closed-loop control as a tool for system characterization. A recently introduced method, the response clamp, extends the voltage clamp rationale to the functional, phenomenological level. The method consists of on-line estimation of a response variable of interest (e.g. the probability of response or its latency and a simple feedback control mechanism designed to tightly converge this variable towards a desired trajectory. In the present contribution I offer a perspective on this novel method and its applications in the broader context of system identification and characterization. First, I demonstrate how internal state variables are exposed using the method, and how the use of several controllers may allow for a detailed, multi-variable characterization of the system. Second, I discuss three different categories of applications of the method: (i exploration of intrinsically generated dynamics, (ii exploration of extrinsically generated dynamics and (iii generation of input-output trajectories. The relation of these categories to similar uses in the voltage clamp and other techniques is also discussed. Finally, I discuss the method’s limitations, as well as its possible synthesis with existing complementary approaches.

  9. Early vs delayed clamping of the umbilical cord in full term, preterm and very preterm infants

    DEFF Research Database (Denmark)

    Moller, N.K.; Weber, T.

    2008-01-01

    Randomized studies from 2006 and two meta-analyses published in 2007 agree that clamping of the umbilical cord can be delayed. For the preterm and very preterm infant benefits include less need for blood transfusion and less morbidity, especially for the very preterm male infant. For the term...

  10. Enhanced Buck-Boost Three-Level Neutral-Point-Clamped Inverters

    DEFF Research Database (Denmark)

    Tan, K. K.; Gao, F.; Chiang Loh, Poh

    2009-01-01

    In traditional three-level neutral-point-clamped (NPC) inverters, a major issue is capacitor voltage imbalance, which results in low order harmonics. The compensation of the capacitor voltages often require additional control complexity, which cannot be conveniently implemented. The "alternative ...

  11. Thermal and Efficiency Analysis of Five-Level Multilevel-Clamped Multilevel Converter Considering Grid Codes

    DEFF Research Database (Denmark)

    Ma, Ke; Muñoz-Aguilar, R. S.; Rodriguez, Pedro;

    2014-01-01

    In this paper, a five-level multilevel-clamped multilevel converter (5L- MLC2) topology is analyzed based on a typical grid integration application for renewable energy system. The loss and thermal distributions of the power devices in different switching legs are investigated and illustrated und...

  12. Pulse and Trapezoidal Voltage Clamp Applied To Jurkat Cells: A T- Lymphocyte Cell Line

    Science.gov (United States)

    1993-04-01

    clamp. (Upward deflection represents depolarization). Low frequency oscillations are clearly visible. Such oscillations have been described by Maltsev ...1952. (8) Maltsev , V. A. Oscillating and triggering properties of T cell membrane potential. Imun. Lett. 26:277-282, 1990. 13 (9) Gallin, E. K

  13. Pulse-Width-Modulation of Neutral-Point-Clamped Sparse Matrix Converter

    DEFF Research Database (Denmark)

    Loh, P.C.; Blaabjerg, Frede; Gao, F.

    2007-01-01

    literature. Addressing the afore-described issues, this paper focuses on the operational mode analysis of a three-level sparse matrix converter implemented using a neutral-point-clamped inversion stage, and  the design of a number of PWM and modulation ratio compensation schemes for controlling the converter...

  14. Trans-Z-source and Γ-Z-source neutral-point-clamped inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    Z-source neutral-point-clamped (NPC) inverters are earlier proposed for obtaining voltage buck-boost and three-level switching simultaneously. Their performances are, however, constrained by a trade-off between their input-to-output gain and modulation ratio. This trade-off can lead to high...

  15. Delayed cord clamping and haemoglobin levels in infancy : a randomised controlled trial in term babies

    NARCIS (Netherlands)

    van Rheenen, Patrick; de Moor, Lette; Eschbach, Sanne; de Grooth, Hannah; Brabin, Bernard

    Objectives This study was carried out to assess whether delaying umbilical cord clamping is effective in improving the haematological status of term infants living in a malaria-endemic area, and whether this is associated with complications in infants and mothers. Metyhods We randomly assigned women

  16. Delayed umbilical cord clamping for reducing anaemia in low birthweight infants : implications for developing countries

    NARCIS (Netherlands)

    van Rheenen, Patrick F.; Gruschke, Sebastian; Brabin, Bernard J.

    BACKGROUND: Cheap and effective interventions are needed to reduce the risk of infant anaemia in developing countries. Delayed cord clamping (DCC) has been shown to be a simple, safe and cost-free delivery procedure that augments red cell mass in appropriate-for-gestational-age term and preterm

  17. Delayed cord clamping in South African neonates with expected low birthweight : a randomised controlled trial

    NARCIS (Netherlands)

    Tiemersma, Sybrich; Heistein, Julia; Ruijne, Roos; Lopez, Gustavo; van Lobenstein, Jeroen; van Rheenen, Patrick

    OBJECTIVE: To evaluate safety and haematological effects of delayed cord clamping (DCC) in infants with expected low birthweight born in a resource-poor setting. METHODS: Randomised controlled trial involving pregnant women in early labour ≥18 years with intrapartum symphysal-fundal height ≤32 cm.

  18. Early umbilical cord clamping contributes to elevated blood lead levels among infants with higher lead exposure.

    Science.gov (United States)

    Chaparro, Camila M; Fornes, Raymond; Neufeld, Lynnette M; Tena Alavez, Gilberto; Eguía-Líz Cedillo, Raúl; Dewey, Kathryn G

    2007-11-01

    To investigate whether infant iron status, modified by umbilical cord clamping time and infant feeding mode, affected infant blood lead concentration at 6 months of age. Participants were a subset of women and their infants randomized to receive early (10 seconds) or delayed (2 minutes) umbilical cord clamping and were monitored to 6 months postpartum in Mexico City. Iron and lead status was analyzed in maternal, placental, and 6-month infant blood samples. Baseline maternal lead exposure data and infant feeding data at 2, 4, and 6 months were collected. In the total sample, maternal blood lead concentration, infant ferritin, and breast-feeding practices predicted infant blood lead concentration. Among infants with higher placental blood lead concentration and breast-fed infants not receiving any iron-fortified formula or milk at 6 months, early clamping increased infant blood lead concentration, an effect mediated in part via decreased infant iron status. Early cord clamping, by decreasing infant iron status, contributes to higher blood lead concentrations at 6 months of age among infants at high risk.

  19. A New Preparation of Pancreatic Ducts for Patch-Clamp Studies

    DEFF Research Database (Denmark)

    Novak, Ivana; Hug, M.J.

    1995-01-01

    parameters, monitored with the whole-cell patch-clamp method, and those in isolated perfused ducts, monitored with the conventional microelectrodes [Novak I, Greger R: Pflügers Arch 1988;411:58-68, 546-553], are comparable. Similar conclusion can be made about the calcium measurements [Hug M, et al: Pflügers...

  20. A direct proofreader-clamp interaction stabilizes the Pol III replicase in the polymerization mode

    NARCIS (Netherlands)

    Jergic, Slobodan; Horan, Nicholas P.; Elshenawy, Mohamed M.; Mason, Claire E.; Urathamakul, Thitima; Ozawa, Kiyoshi; Robinson, Andrew; Goudsmits, Joris M. H.; Wang, Yao; Pan, Xuefeng; Beck, Jennifer L.; van Oijen, Antoine M.; Huber, Thomas; Hamdan, Samir M.; Dixon, Nicholas E.

    2013-01-01

    Processive DNA synthesis by the alpha epsilon theta core of the Escherichia coli Pol III replicase requires it to be bound to the beta(2) clamp via a site in the a polymerase subunit. How the epsilon proofreading exonuclease subunit influences DNA synthesis by alpha was not previously understood. In

  1. Glucose consumption by various tissues in pregnant rats : effects of a 6-day euglycaemic hyperinsulinaemic clamp

    NARCIS (Netherlands)

    Nieuwenhuizen, AG; Schuiling, GA; Bonen, A; Paans, AMJ; Vaalburg, W; Koiter, TR

    1998-01-01

    In the course of pregnancy maternal tissues become increasingly more insensitive to insulin. As 6 days of euglycaemic hyperinsulinaemic clamping, from day 8 until 14 of gestation, ameliorates total glucose consumption, we analysed the contribution of individual tissues in this phenomenon. We measure

  2. Experimental and numerical analysis of clamped joints in front motorbike suspensions

    Directory of Open Access Journals (Sweden)

    Vincenzi N.

    2010-06-01

    Full Text Available Clamped joints are shaft-hub connections used, as an instance, in front motorbike suspensions to lock the steering plates with the legs and the legs with the wheel pin, by means of one or two bolts. The preloading force, produced during the tightening process, should be evaluated accurately, since it must lock safely the shaft, without overcoming the yielding point of the hub. Firstly, friction coefficients have been evaluated on “ad-hoc designed” specimens, by applying the Design of Experiment approach: the applied tightening torque has been precisely related to the imposed preloading force. Then, the tensile state of clamps have been evaluated both via FEM and by leveraging some design formulae proposed by the Authors as function of the preloading force and of the clamp geometry. Finally, the results have been compared to those given by some strain gauges applied on the tested clamps: the discrepancies between numerical analyses, the design formulae and the experimental results remains under a threshold of 10%.

  3. A bulldog clamp that was forgotten during a coronary artery bypass operation 8 years ago.

    Science.gov (United States)

    Celkan, Mehmet Adnan; Bayatli, Kivanc

    2012-10-01

    Prevention of retained foreign bodies in the pericardial cavity is critical for patient safety. We report a patient with a bulldog clamp that was forgotten during a coronary artery bypass operation 8 years ago, which was detected by chance and removed.

  4. Calcium Release in Frog Cut Twitch Fibers Exposed to Different Ionic Environments under Voltage Clamp

    National Research Council Canada - National Science Library

    Hui, Chiu Shuen

    1999-01-01

    Calcium release was measured in highly stretched frog cut twitch fibers mounted in a double Vaseline-gap voltage clamp chamber, with the internal solution containing 20 mM EGTA plus 0.4 or 1.8 mM added calcium...

  5. Angle of arrival estimation using spectral interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Z.W.; Harrington, C.; Thiel, C.W.; Babbitt, W.R. [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States); Krishna Mohan, R., E-mail: krishna@spectrum.montana.ed [Spectrum Lab, Montana State University, Bozeman, MT 59717 (United States)

    2010-09-15

    We have developed a correlative signal processing concept based on a Mach-Zehnder interferometer and spatial-spectral (S2) materials that enables direct mapping of RF spectral phase as well as power spectral recording. This configuration can be used for precise frequency resolved time delay estimation between signals received by a phased antenna array system that in turn could be utilized to estimate the angle of arrival. We present an analytical theoretical model and a proof-of-principle demonstration of the concept of time difference of arrival estimation with a cryogenically cooled Tm:YAG crystal that operates on microwave signals modulated onto a stabilized optical carrier at 793 nm.

  6. MATLAB implementation of a dynamic clamp with bandwidth >125 KHz capable of generating INa at 37°C

    Science.gov (United States)

    Clausen, Chris; Valiunas, Virginijus; Brink, Peter R.; Cohen, Ira S.

    2012-01-01

    We describe the construction of a dynamic clamp with bandwidth >125 KHz that utilizes a high performance, yet low cost, standard home/office PC interfaced with a high-speed (16 bit) data acquisition module. High bandwidth is achieved by exploiting recently available software advances (code-generation technology, optimized real-time kernel). Dynamic-clamp programs are constructed using Simulink, a visual programming language. Blocks for computation of membrane currents are written in the high-level matlab language; no programming in C is required. The instrument can be used in single- or dual-cell configurations, with the capability to modify programs while experiments are in progress. We describe an algorithm for computing the fast transient Na+ current (INa) in real time, and test its accuracy and stability using rate constants appropriate for 37°C. We then construct a program capable of supplying three currents to a cell preparation: INa, the hyperpolarizing-activated inward pacemaker current (If), and an inward-rectifier K+ current (IK1). The program corrects for the IR drop due to electrode current flow, and also records all voltages and currents. We tested this program on dual patch-clamped HEK293 cells where the dynamic clamp controls a current-clamp amplifier and a voltage-clamp amplifier controls membrane potential, and current-clamped HEK293 cells where the dynamic clamp produces spontaneous pacing behavior exhibiting Na+ spikes in otherwise passive cells. PMID:23224681

  7. Evaluation of diel patterns of relative changes in cell turgor of tomato plants using leaf patch clamp pressure probes

    NARCIS (Netherlands)

    Lee, K.M.; Driever, S.M.; Heuvelink, E.; Rüger, S.; Zimmermann, U.; Gelder, de A.; Marcelis, L.F.M.

    2012-01-01

    Relative changes in cell turgor of leaves of well-watered tomato plants were evaluated using the leaf patch clamp pressure probe (LPCP) under dynamic greenhouse climate conditions. Leaf patch clamp pressure changes, a measure for relative changes in cell turgor, were monitored at three different hei

  8. An AFM-based stiffness clamp for dynamic control of rigidity.

    Directory of Open Access Journals (Sweden)

    Kevin D Webster

    Full Text Available Atomic force microscopy (AFM has become a powerful tool for measuring material properties in biology and imposing mechanical boundary conditions on samples from single molecules to cells and tissues. Constant force or constant height can be maintained in an AFM experiment through feedback control of cantilever deflection, known respectively as a 'force clamp' or 'position clamp'. However, stiffness, the third variable in the Hookean relation F = kx that describes AFM cantilever deflection, has not been dynamically controllable in the same way. Here we present and demonstrate a 'stiffness clamp' that can vary the apparent stiffness of an AFM cantilever. This method, employable on any AFM system by modifying feedback control of the cantilever, allows rapid and reversible tuning of the stiffness exposed to the sample in a way that can decouple the role of stiffness from force and deformation. We demonstrated the AFM stiffness clamp on two different samples: a contracting fibroblast cell and an expanding polyacrylamide hydrogel. We found that the fibroblast, a cell type that secretes and organizes the extracellular matrix, exhibited a rapid, sub-second change in traction rate (dF/dt and contraction velocity (dx/dt in response to step changes in stiffness between 1-100 nN/µm. This response was independent of the absolute contractile force and cell height, demonstrating that cells can react directly to changes in stiffness alone. In contrast, the hydrogel used in our experiment maintained a constant expansion velocity (dx/dt over this range of stiffness, while the traction rate (dF/dt changed with stiffness, showing that passive materials can also behave differently in different stiffness environments. The AFM stiffness clamp presented here, which is applicable to mechanical measurements on both biological and non-biological samples, may be used to investigate cellular mechanotransduction under a wide range of controlled mechanical boundary

  9. Influence of phenylephrine or ephedrine on maternal hemodynamics upon umbilical cord clamping during cesarean delivery.

    Science.gov (United States)

    Quan, Zhefeng; Tian, Ming; Chi, Ping; Cao, Yinghao; Li, Xin; Peng, Kejun

    2013-11-01

    Vasopressors ephedrine and phenylephrine are commonly used with spinal anesthesia during cesarean delivery. Studies on them have focused on the period before the umbilical cord is clamped, although anesthesia is continuously administered throughout and after this event. This study aimed to compare the effects of these drugs on maternal hemodynamics at and after clamping of the umbilical cord. Prospective, randomized, double-blind study. Parturients (n = 60) scheduled for elective cesarean delivery were randomly divided into an ephedrine group and a phenylephrine group. Each woman received an intrathecal injection of bupivacaine (7.5 mg). Patients in the ephedrine and phenylephrine groups were infused continuously with ephedrine (0.02 mg×kg-1×min-1) or phenylephrine (0.25 μg×kg-1×min-1), respectively, from immediately after the injection of bupivacaine until termination 10 minutes after the umbilical cord was clamped (the endpoint). Hemodynamic changes were recorded. After clamping the umbilical cord, the patients who were administered ephedrine experienced significant increases in heart rate (89 ± 11 beats/min to 106 ± 15 beats/min), cardiac output (6.4 ± 0.9 l/min to 7.6 ± 1.2 l/min) and cardiac index (3.5 ± 0.39 l×min-1×m-2 to 4.3 ± 0.48 l×min-1×m-2), while the systemic vascular resistance decreased (908 ± 296 dyne·s/cm5 to 711 ± 285 dyne·s/cm5). Such differences were not observed in the patients who received phenylephrine. Moreover, the heart rate of patients administered ephedrine was higher than that of patients given phenylephrine after clamping the umbilical cord. Continuous infusion of phenylephrine during cesarean delivery maintains a stable maternal hemodynamic status better than ephedrine.

  10. A physiological approach to the timing of umbilical cord clamping at birth.

    Science.gov (United States)

    Hooper, Stuart B; Polglase, Graeme R; te Pas, Arjan B

    2015-07-01

    Umbilical cord clamping at birth has a major impact on an infant's cardiovascular system that varies in significance depending upon whether the infant has commenced breathing. As umbilical venous return is a major source of preload for the left ventricle during fetal life, recent experimental evidence has shown that clamping the umbilical cord severely limits cardiac venous return in the absence of pulmonary ventilation. As a result, cardiac output greatly reduces and remains low until breathing commences. Once the infant begins breathing, aeration of the lung triggers a large increase in pulmonary blood flow, which replaces umbilical venous return as the source of preload for the left ventricle. As a result, cardiac output markedly increases, as indicated by an increase in heart rate immediately after birth. Thus, infants born apnoeic and hypoxic and have their cords immediately clamped, are likely to have a restricted cardiac output combined with hypoxia. As increased cardiac output is a major physiological defence mechanism that counteracts the effects of hypoxaemia, limiting the increase in cardiac output exposes the infant to ischaemia along with hypoxia. However, if the infant commences breathing, aerates its lungs and increases pulmonary blood flow before the umbilical cord is clamped, then pulmonary venous return can immediately take over the supply of left ventricular preload upon cord clamping. As a result, there is no intervening period of reduced preload and cardiac output and the large swings in arterial pressures and flows are reduced leading to a more stable circulatory transition. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Ventilation before Umbilical Cord Clamping Improves the Physiological Transition at Birth.

    Science.gov (United States)

    Bhatt, Sasmira; Polglase, Graeme R; Wallace, Euan M; Te Pas, Arjan B; Hooper, Stuart B

    2014-01-01

    The transition from a fetus to a neonate at birth represents a critical phase in our life. Most infants make this transition without complications, but preterm infants usually require some form of assistance due to immature cardiopulmonary systems that predispose them to lifelong sequelae. As the incidence of preterm birth is increasing, there is now an urgent need for the development of management strategies that facilitate this transition, which will likely include improved strategies for the management of the maternal third stage of labor. For instance, recent studies on the physiological transition at birth have led to the discovery that establishing ventilation in the infant before the umbilical cord is clamped greatly stabilizes the cardiovascular transition at birth. While most benefits of delayed clamping previously have been attributed to an increase in placenta to infant blood transfusion, clearly there are other significant benefits for the infant, which are not well understood. Nevertheless, if ventilation can be established before cord clamping in a preterm infant, the large adverse changes in cardiac function that normally accompanies umbilical cord clamping can be avoided. As preterm infants have an immature cerebral vascular bed, large swings in cardiovascular function places them at high risk of cerebral vascular rupture and the associated increased risk of mortality and morbidity. In view of the impact that cord clamping has on the cardiovascular transition at birth, it is also time to re-examine some of the strategies used in the management of the third stage of labor. These include the appropriate timing of uterotonic administration in relation to delivery of the infant and placenta. As there is a lack of evidence on the effects these individual practices have on the infant, there is a necessity to improve our understanding of their impact in order to develop strategies that facilitate the transition to newborn life.

  12. An AFM-based stiffness clamp for dynamic control of rigidity.

    Science.gov (United States)

    Webster, Kevin D; Crow, Ailey; Fletcher, Daniel A

    2011-03-08

    Atomic force microscopy (AFM) has become a powerful tool for measuring material properties in biology and imposing mechanical boundary conditions on samples from single molecules to cells and tissues. Constant force or constant height can be maintained in an AFM experiment through feedback control of cantilever deflection, known respectively as a 'force clamp' or 'position clamp'. However, stiffness, the third variable in the Hookean relation F = kx that describes AFM cantilever deflection, has not been dynamically controllable in the same way. Here we present and demonstrate a 'stiffness clamp' that can vary the apparent stiffness of an AFM cantilever. This method, employable on any AFM system by modifying feedback control of the cantilever, allows rapid and reversible tuning of the stiffness exposed to the sample in a way that can decouple the role of stiffness from force and deformation. We demonstrated the AFM stiffness clamp on two different samples: a contracting fibroblast cell and an expanding polyacrylamide hydrogel. We found that the fibroblast, a cell type that secretes and organizes the extracellular matrix, exhibited a rapid, sub-second change in traction rate (dF/dt) and contraction velocity (dx/dt) in response to step changes in stiffness between 1-100 nN/µm. This response was independent of the absolute contractile force and cell height, demonstrating that cells can react directly to changes in stiffness alone. In contrast, the hydrogel used in our experiment maintained a constant expansion velocity (dx/dt) over this range of stiffness, while the traction rate (dF/dt) changed with stiffness, showing that passive materials can also behave differently in different stiffness environments. The AFM stiffness clamp presented here, which is applicable to mechanical measurements on both biological and non-biological samples, may be used to investigate cellular mechanotransduction under a wide range of controlled mechanical boundary conditions.

  13. Ventilation before Umbilical Cord Clamping improves the physiological transition at birth.

    Directory of Open Access Journals (Sweden)

    Sasmira eBhatt

    2014-10-01

    Full Text Available The transition from a fetus to a neonate at birth represents a critical phase in our life. Most infants make this transition without complications, but preterm infants usually require some form of assistance due to immature cardiopulmonary systems that predispose them to lifelong sequelae. As the incidence of preterm birth is increasing, there is now an urgent need for the development of management strategies that facilitate this transition, which will likely include improved strategies for the management of the maternal third stage of labour. For instance, recent studies on the physiological transition at birth have led to the discovery that establishing ventilation in the infant before the umbilical cord is clamped greatly stabilizes the cardiovascular transition at birth. While most benefits of delayed clamping have previously been attributed to an increase in placenta to infant blood transfusion, clearly there are other significant benefits for the infant, which are not well understood. Nevertheless, if ventilation can be established before cord clamping in a preterm infant, the large adverse changes in cardiac function that normally accompanies umbilical cord clamping can be avoided. As preterm infants have an immature cerebral vascular bed, large swings in cardiovascular function places them at high risk of cerebral vascular rupture and the associated increased risk of mortality and morbidity. In view of the impact that cord clamping has on the cardiovascular transition at birth, it is also time to re-examine some of the strategies used in the management of the third stage of labour. These include the appropriate timing of uterotonic administration in relation to delivery of the infant and placenta. As there is a lack of evidence on the effects these individual practices have on the infant, there is a necessity to improve our understanding of their impact in order to develop strategies that facilitate the transition to newborn life.

  14. Generalization of the Euler Angles

    Science.gov (United States)

    Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis

    2002-01-01

    It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.

  15. Optical atomic magnetometer

    Science.gov (United States)

    Budker, Dmitry; Higbie, James; Corsini, Eric P

    2013-11-19

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  16. Small angle neutron scattering

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of

  17. Paraxial Ray Optics Cloaking

    CERN Document Server

    Choi, Joseph S

    2014-01-01

    Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak using ray optics, albeit with some edge effects. Our device requires no new materials, uses isotropic off-the-shelf optics, scales easily to cloak arbitrarily large objects, and is as broadband as the choice of optical material, all of which have been challenges for current cloaking schemes. In addition, we provide a concise formalism that quantifies and produces perfect optical cloaks in the small-angle (`paraxial') limit, and must be satisfied by any good cloaks.

  18. Behaviour of lab parameters and neonatal weight loss in relation to neonatal breathing movements and cord clamping time.

    Science.gov (United States)

    Indraccolo, U; Santafata, R; Palazzetti, P L; Di Iorio, R; Indraccolo, S R

    2013-01-01

    To date, delaying cord clamping two to three minutes after birth is considered effective for newborn well-being. This time does not consider the newborn's breathing movements, which may also condition neonate well-being. To investigate the behaviour of neonatal weight loss and of some umbilical vein lab parameters, in relation to timing of newborn breathing and cord clamping. Time from birth to cord clamping and time from birth to first cry of the newborn were collected in 87 full-term healthy women. First cry is a sign of effective breathing. Birth weight loss at the first, second, and third day from birth and lab parameters were assessed in relation to: time from birth to cord clamping, time from birth to first cry, and cord clamping before or after the first cry. Partial pressure of carbon dioxide (pCO2) decreased if cord clamping was performed after first cry and increased if first cry occurred after cord clamping, independently from the time elapsed from birth to first cry (p = 0.012). Calcium (Ca(2+)) concentration decreased if cord clamping was performed after the first cry and increased if first cry of the baby after birth was delayed (p = 0.021). Each second of delay from birth to cord clamping resulted in an increase in Cl- concentration (p cord clamping resulted in a reduction in the percentage of weight loss at the first day (p = 0.024), at the second day (p = 0.007), and at the third day (p = 0.028) after birth. Neonate breathing after birth should induce umbilical vein flow from placenta to lungs, conditioning the reduction of birth weight loss after birth and umbilical lab parameters modifications.

  19. An observational study of umbilical cord clamping practices of maternity care providers in a tertiary care center.

    Science.gov (United States)

    Hutton, Eileen K; Stoll, Kathrin; Taha, Natalie

    2013-03-01

    Severing the umbilical cord at birth is likely the oldest intervention, the timing of which remains fraught with controversy. Emerging evidence suggests benefit in delaying cord clamping for both term and preterm infants. The objective of this study was to investigate actual cord clamping time and circumstances at a large tertiary care center in Canada. We used a stopwatch to time the interval from the time the infant was born as far as the umbilicus until the time that the umbilical cord was clamped before cutting. We reported on timing of the umbilical cord clamping overall and by practitioner group (obstetrician, midwife, and family practitioner). A total of 98 women and their practitioners consented to be observed at the British Columbia Women's Hospital and Health Center, Vancouver, Canada. More than one-half (56.2%) of all infants had their umbilical cord clamped within 15 seconds. The median (5th, 95th percentile) clamping time in seconds for the full sample was 12 (4, 402) with practitioner subgroups as follows: obstetricians (12 [3, 107]), family physicians (19 [6, 325]), and midwives (81 [6, undefined]). The median clamping time was likely to be longer when the birth occurred spontaneously, no umbilical cord blood was collected, and no birth or neonatal complications occurred. In our sample taken in 2006 to 2007, most infants had umbilical cords clamped immediately after the birth, with more than one-half clamped within 15 seconds of birth. Since the time of our study, delayed umbilical cord clamping for the healthy term newborn has become a part of recommended management of third stage of labor and resuscitation guidelines. It would be informative to repeat a study like this one to determine compliance with the current standards of care. © 2013, Copyright the Authors Journal compilation © 2013, Wiley Periodicals, Inc.

  20. New machining and testing method of large angle infrared wedge mirror parts

    Science.gov (United States)

    Su, Ying; Guo, Rui; Zhang, Fumei; Zhang, Zheng; Liu, Xuanmin; Zengqi, Xu; Li, Wenting; Zhang, Feng

    2016-10-01

    Large angle wedge parts were widely used in the optical system that was used for achieving a wide range of scanning. Due to the parts having the characteristic of large difference in the thickness of both ends and high density, the accuracy of the wedge angle was hard to ensure to reach second level in optical processing. Generally, wedge mirror angle was measured by contact comparison method which was easy to damage the surface. In view of the existence of two practical problems, in this paper, based on theoretical analysis, by taking three key measures that were the accurate positioning for the central position of the large angle wedge part, the accuracy control of angle precision machined of wedge mirror and fast and non destructive laser assisted absolute measurement of large angle wedge, the qualified rate of parts were increased to 100%, a feasible, controllable and efficient process route for large angle infrared wedge parts was found out.

  1. 大视场高分辨力星载成像光谱仪光学系统设计%Optical System Design of Wide-Angle and High-Resolution Spaceborne Imaging Spectrometer

    Institute of Scientific and Technical Information of China (English)

    薛庆生; 黄煜; 林冠宇

    2011-01-01

    大视场、高分辨力星载成像光谱仪已成为空间遥感的迫切需求.根据大视场、高分辨力的研究目标,提出了先视场分离分光再用分色片分光的设计方法,分析了视场分离分光的原理.设计了一个全反射式星载成像光谱仪光学系统,该系统由指向镜、11.42°远心离轴三反消像散(TMA)前置望远系统和4个Offner凸面光栅光谱成像系统组成,通过恰当选择4个光谱成像系统的变倍比来实现2种探测器的匹配.运用光学设计软件CODE V对成像光谱仪调制系统进行了光线追迹和优化,并对设计结果进行了分析.分析结果表明,光学系统在各个谱段的光学传递函数均达到0.7以上,完全满足设计指标要求;同时证明了设计方法是可行的.%Space remote sensing urgently requires wide-angle and high-resolution spaceborne imaging spectrometer. According to the research objective of wide angle and high resolution, the design method of firstly dividing field of view (FOV) and secondly dividing beam using dichroscope is developed. The principle of dividing FOV is analyzed. A reflective spaceborne imaging spectrometer is designed, which is composed of a pointing mirror, a 11.42° telecentric off-axis three-mirror anastigmatic (TMA) telescope and four Offner convex grating spectral imaging systems. The proper magnification is chosen for each spectral imaging system to match two types of detectors. Ray tracing and optimization are performed and analyzed by CODE V software. The results demonstrate that the modulation transfer function (MTF) for different spectral bands is more than 0. 7, which satisfies the pre-designed requirement. The design method is proved to be feasible.

  2. Active limited-angle tomographic phase microscope.

    Science.gov (United States)

    Kus, Arkadiusz; Krauze, Wojciech; Kujawinska, Malgorzata

    2015-01-01

    We demonstrate an active, holographic tomography system, working with limited angle of projections, realized by optical-only, diffraction-based beam steering. The system created for this purpose is a Mach–Zehnder interferometer modified to serve as a digital holographic microscope with a high numerical aperture illumination module and a spatial light modulator (SLM). Such a solution is fast and robust. Apart from providing an elegant solution to viewing angle shifting, it also adds new capabilities of the holographic microscope system. SLM, being an active optical element, allows wavefront correction in order to improve measurement accuracy. Integrated phase data captured with different illumination scenarios within a highly limited angular range are processed by a new tomographic reconstruction algorithm based on the compressed sensing technique: total variation minimization, which is applied here to reconstruct nonpiecewise constant samples. Finally, the accuracy of full measurement and the proposed processing path is tested for a calibrated three-dimensional micro-object as well as a biological object--C2C12 myoblast cell.

  3. Off-clamp robot-assisted partial nephrectomy does not benefit short-term renal function: a matched cohort analysis.

    Science.gov (United States)

    Anderson, Barrett G; Potretzke, Aaron M; Du, Kefu; Vetter, Joel; Figenshau, R Sherburne

    2017-08-31

    In the interest of renal functional preservation, partial nephrectomy has supplanted radical nephrectomy as the preferred treatment for T1 renal masses. This procedure usually involves the induction of renal warm ischemia by clamping the hilar vessels prior to tumor excision. Performing robot-assisted partial nephrectomy (RAPN) "off-clamp" can theoretically prevent renal functional loss associated with warm ischemia. We describe our institutional experience and compare perioperative and renal functional outcomes using a propensity score matched cohort. We conducted a retrospective comparison from a prospectively maintained database of all patients who underwent RAPN from 2009 to 2015. Of those patients, 143 underwent off-clamp RAPN. Fifty off-clamp RAPN patients were propensity score matched with fifty clamped RAPN patients based on renal function, tumor size, and R.E.N.A.L. nephrometry score. The cohorts were compared across demographics, operative information, perioperative outcomes, and renal functional outcomes. For all off-clamp RAPN patients, mean nephrometry score was 7.1, mean estimated blood loss (EBL) was 236.9 mL, perioperative complication rate was 7.7%, and mean decrease in estimated glomerular filtration rate (eGFR) was 7.1% at a median follow-up of 9.2 months. In the propensity score matched cohorts, off-clamp RAPN resulted in a shorter mean operative time (172.0 versus 196.0 min, p = 0.025) and a lower mean EBL (179.7 versus 283.2 mL, p = 0.046). A lower complication rate of 6.0% in the off-clamp group compared with 20.0% in the clamped group approached significance (p = 0.071). Mean preoperative eGFR was similar in both cohorts. Importantly, there was no significant difference in decrease in eGFR between the clamped cohort (9.8%) and off-clamp cohort (11.9%) at a median follow-up of 9.0 months (p = 0.620). Off-clamp RAPN did not result in improved renal functional preservation in our experience. Surprisingly, the off-clamp cohort

  4. Induction of DNA DSB and its rejoining in clamped and non-clamped tumours after exposure to carbon ion beams in comparison to X rays.

    Science.gov (United States)

    Hirayama, R; Uzawa, A; Matsumoto, Y; Noguchi, M; Kase, Y; Takase, N; Ito, A; Koike, S; Ando, K; Okayasu, R; Furusawa, Y

    2011-02-01

    We studied double-strand breaks (DSB) induction and rejoining in clamped and non-clamped transplanted tumours in mice leg after exposure to 80 keV µm(-1) carbon ions and X rays. The yields of DSB in the tumours were analysed by a static-field gel electrophoresis. The OER of DSB after X rays was 1.68±0.31, and this value was not changed after 1 h rejoining time (1.40±0.26). These damages in oxygenated conditions were rejoined 60-70% within 1 h in situ. No difference was found between the exposure to X rays and carbon ions for the induction and rejoining of DSB. Thus, the values of OER and rejoined fraction after exposure to carbon ions were similar to those after X rays, and the calculated relative biological effectivenesses of carbon ion were around 1 under both oxygen conditions. The yields of DSB in vivo depend on exposure doses, oxygen conditions and rejoining time, but not on the types of radiation quality.

  5. Bessel-like beams with z-dependent cone angles

    CSIR Research Space (South Africa)

    Belyi, VN

    2009-08-01

    Full Text Available A new type of Bessel-like optical beams, which is distinguished by the dependence on the cone angle from the longitudinal coordinate, is investigated. Such beams have the properties of Bessel beams (ring-spatial spatial spectrum) as well as Gaussian...

  6. Measuring static and dynamic contact angles using a liquid needle

    Science.gov (United States)

    Sanedrin, Raymond; Jin, Ming; Frese, Daniel; Scheithauer, Carsten; Willers, Thomas

    2016-11-01

    The optical determination of static and advancing contact angle is made on drops applied or extended, respectively, onto a substrate through the use of thin solid needles. Although this method has been used extensively, this method of dosing can be time consuming, cumbersome and if not meticulously performed can lead to erroneous contact angle results. Herein, we present an alternative way of applying drops onto substrates using a small liquid jet, which is produced by a liquid pressure dosing system acting as a "liquid needle." A comparative static contact angle study on 14 different surfaces with two different liquids were performed utilizing two different ways of dosing: the conventional solid and a novel liquid needle based technique. We found, for all but one sample, that the obtained results were highly comparable. Observed differences can be explained by the characteristics of either way of dosing. In addition, we used the liquid pressure based dosing system for optical advancing contact angle measurement on two different samples. The liquid needle based method facilitates the expansion of a drop from 0.1 to 22 μL within less than 1.2 seconds, which provided constant contact angle versus drop base diameter curves. The obtained results were highly comparable with dynamic Wilhelmy contact angle measurements.

  7. Optics/Optical Diagnostics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Optics/Optical Diagnostics Laboratory supports graduate instruction in optics, optical and laser diagnostics and electro-optics. The optics laboratory provides...

  8. Design and experimental research of a novel inchworm type piezo-driven rotary actuator with the changeable clamping radius.

    Science.gov (United States)

    Zhao, Hongwei; Fu, Lu; Ren, Luquan; Huang, Hu; Fan, Zunqiang; Li, Jianping; Qu, Han

    2013-01-01

    In this paper, a novel piezo-driven rotary actuator with the changeable clamping radius is developed based on the inchworm principle. This actuator mainly utilizes three piezoelectric actuators, a flexible gripper, a clamping block, and a rotor to achieve large stroke rotation with high resolution. The design process of the flexible gripper consisting of the driving unit and the clamping unit is described. Lever-type mechanisms were used to amplify the micro clamping displacements. The amplifying factor and parasitic displacement of the lever-type mechanism in the clamping unit was analyzed theoretically and experimentally. In order to investigate the rotation characteristics of the actuator, a series of experiments was carried out. Experimental results indicate that the actuator can rotate at a speed of 77,488 μrad/s with a driving frequency of 167 Hz. The rotation resolution and maximum load torque of the actuator are 0.25 μrad and 37 N mm, respectively. The gripper is movable along the z direction based on an elevating platform, and the clamping radius can change from 10.6 mm to 25 mm. Experimental results confirm that the actuator can achieve different rotation speeds by changing the clamping radius.

  9. Conformal analysis of fundamental frequency of vibration of elastic clamped plates

    Institute of Scientific and Technical Information of China (English)

    QI Hongyuan; ZHU Hengjun

    2007-01-01

    To calculate the fundamental frequency of vibration of special-shaped and elastic clamped plates, the conformal mapping theory is adopted to separate the interpolating points of a complicated boundary into odd and even sequences,both of which can be mutually iterated, so that the conformal mapping function between the complicated region and the unit dish region is established. Trigonometric interpolation and convergence along the normal direction methods are provided, and the complex coefficients of the conformal mapping function are calculated. Galerkin method is used to obtain the solution of fundamental frequency in the vibrating differential function of the complicated vibrating region.Finally, taking ellipse elastic clamped plates as an example,the effects on fundamental frequency coefficient caused by eccentric ratio e and area size are analyzed.

  10. Testing and evaluation of stretching strain in clamped–clamped beams for energy harvesting

    Science.gov (United States)

    Emad, Ahmed; Mahmoud, Mohamed A. E.; Ghoneima, Maged; Dessouky, Mohamed

    2016-11-01

    In this paper, evaluation of stretching strain capabilities to harvest energy from a piezoelectric clamped–clamped beam is theoretically modeled and experimentally tested. The utilization of stretching strain has many advantages as: elimination of any substrate material, and the simple electrode configuration. The doubly clamped structure exhibits a highly nonlinear frequency response (Hardening Duffing) that widens the bandwidth during the frequency up-ward sweep. The wide bandwidth makes it suitable for practical applications. A design of 53.5 {{mm}}3 (29.7 {{mm}}3 piezoelectric material + 23.8 {{mm}}3 proof mass) energy harvester was tested using PVDF (polyvinylidene fluoride) that can generate up to 15 μW from vibrations of 0.5{g} at 128 {Hz} and 2 MΩ load. The design can also generate up to 41 μ {{W}} from vibrations of 1{g} at 140 {Hz} and 2 MΩ load.

  11. High Efficiency Interleaved Active Clamped Dc-Dc Converter with Fuel Cell for High Voltage Applications

    Directory of Open Access Journals (Sweden)

    Sona P

    2014-02-01

    Full Text Available A high efficiency interleaved ZVS active clamped current fed dc-dc converter is proposed in this paper specially used for fuel cell applications. As the fuel cell output is very low we are in need of a step up dc-dc converter. Here a current fed dc-dc converter is used. Two current fed dc-dc converters are interleaved by connecting their inputs in parallel and outputs in series. With this proposed methodology input current ripples in the fuel cell stacks can be reduced and a regulated output voltage ripples can be obtained. The active clamping circuit used in this model absorbs the turn off voltage spikes hence low voltage devices with low on state resistance can be used.Voltage doubler circuits will give double the output voltage than normal with smaller transformer turns ratio and flexibility. The proposed method is simulated in MATLAB for verifying the accuracy of the proposed design.

  12. Influence of non-steady state during isoglycemic hyperinsulinemic clamp in hypertension. A LIFE substudy

    DEFF Research Database (Denmark)

    Olsen, M H; Andersen, U B; Wachtell, K;

    1999-01-01

    We wanted to investigate whether time to steady state was reached within 2 h of insulin infusion during isoglycemic hyperinsulinemic clamp, comparing the glucose uptake index (M/IG) with Bergman's insulin sensitivity index (Sip). We performed a 2-h oral glucose tolerance test and a 3-h isoglycemic...... hyperinsulinemic clamp in 26 young, healthy subjects and 43 elderly patients with unmedicated essential hypertension and left ventricular hypertrophy. The 3-h Sip correlated strongly with the 2-h M/IG in the patients (r = 0.88, p ... narrow limits of agreement in the patients. However, during the third hour of insulin infusion, M/IG (10.0 vs 12.21(2) x kg(-1) x min(-1) x mmol(-1), p Sip (7.1 vs 9.41(2) x kg(-1) x min(-1) x mmol(-1), p

  13. Study of transmembrane La3+ movement in rat ventricular myocytes by the patch-clamp technique

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We have studied transmembrane La3+ movement in rat ventricular myocytes for the first time by using the whole-cell patch-clamp recording mode. La3+ (0.01-5.0 mmol/L) could not bring out inward currents through the L-type calcium channel in rat ventricular myocytes, while it could enter the cells by the same way carried by 1μmol/L ionomycin. When the outward Na+ concentration gradient is formed, La3+ can enter the cells via Na-Ca exchange, and the exchange currentsincrease with the increase of external La3+ concentrations. But compared with Na-Ca exchange currents in the same concentration, the former is only 14%-38% of the latter. The patch-clamp experiment indicates that La3+ normally can not enter ventricular myocytes through L-type calcium channel, but it can enter the cells via Na-Ca exchange.

  14. [Traumatic section of the thoracic aorta: its repair by direct aortic clamping].

    Science.gov (United States)

    Cairols, M A; Sieyro, F; Miralles, M; Blanes, I; Lozano, P

    1991-01-01

    Traumatic section of descendent aorta, severe complication of a thoracic traumatism, requires an early recognition and restoration because its high mortality rate. Between 1988 and 1990, three patients underwent surgical approach, by direct aortic clamping [correction of clamplaje], at our Service. In two cases, a heart stoppage appeared during the clamping/unclamping [correction of clampaje/desclampaje] maneuvers. One of them had previously electrocardiographic abnormalities, suggestive of heart contusion. Two patients died, one of them during surgical procedure because an irreversible heart stoppage, and the second patient died after 7 days because of a brain hemorrhage. One case presented postoperative paraplegia. Respective rates and literature about the main factors implicated in the diagnosis and treatment of such pathology are reviewed.

  15. Short Hypoxia Does not Affect Plasma Leptin in Healthy Men under Euglycemic Clamp Conditions

    Directory of Open Access Journals (Sweden)

    Andre Schmoller

    2009-01-01

    Full Text Available Leptin is involved in the endocrine control of energy expenditure and body weight regulation. Previous studies emphasize a relationship between hypoxic states and leptin concentrations. The aim of this study was to investigate the effects of acute hypoxia on leptin concentrations in healthy subjects. We examined 14 healthy men. Hypoxic conditions were induced by decreasing oxygen saturation to 75% for 30 minutes. Plasma leptin concentrations were determined at baseline, after 3 hours of euglycemic clamping, during hypoxia, and repeatedly the following 2.5 hours thereafter. Our results show an increase of plasma leptin concentrations in the course of 6 hours of hyperinsulinemic-euglycemic clamping which may reflect diurnal rhythmicity. Notwithstanding, there was no difference between levels of leptin in the hypoxic and the normoxic condition (=.2. Since we did not find any significant changes in leptin responses upon hypoxia, plasma leptin levels do not seem to be affected by short hypoxic episodes of moderate degree.

  16. [The Impact of Late Umbilical Cord Clamping on Neonatal Jaundice and Postpartum Hemorrhage: A Randomized Controlled Trail].

    Science.gov (United States)

    Chien, Pei-Chun; Yang, Cherng-Chia; Gau, Meei-Ling; Liu, Chieh-Yu; Lee, Tzu-Ying

    2015-08-01

    The current evidence supports the clinical benefits of late umbilical cord clamping. These benefits include increased blood volume and total body iron. Furthermore, delayed cord clamping facilitates the transplantation of stem cells, which helps the development of infant bodily systems. However, due to concerns related to postpartum hemorrhaging and neonate jaundice, most maternity units still clamp the cord immediately after a child is born. This study investigates the impact of delaying cord clamping on neonatal jaundice and postpartum hemorrhage. A randomized, controlled trial was conducted at a regional teaching hospital in northern Taiwan. One hundred and five healthy nulliparous women at 36 weeks of pregnancy were included and allocated randomly to the experiment group (n=44) and the control group (n=61). Participants in the experiment group received delayed cord clamping (DCC) at 3 minutes after delivery. Participants in the control group received early cord clamping (ECC) at around 1 minute after delivery. Clinical measures of the outcomes were measured by the infant transcutaneous bilirubin levels (TcB) and postpartum hemorrhage at birth. A structured questionnaire and biophysical measures were used to collect data on participant demographics, obstetrical information, maternal blood loss at birth, neonate weight and TcB level at hospitalization, and whether or not the infant received phototherapy at 4-7 days postpartum. Overall, there was no significant difference between the two groups in terms of neonatal jaundice, maternal hemorrhage at birth, and phototherapy rates at time of hospitalization and at 4-7 days postpartum. The findings of the present study support that late umbilical cord clamping does not increase the risk of maternal postpartum hemorrhaging or neonate jaundice. Thus, we suggest that clinicians inform clients during prenatal classes of the benefits of delayed cord clamping and also use current, evidence-based knowledge to dispel client

  17. Early versus delayed cord clamping in term and preterm births: a review.

    Science.gov (United States)

    Garofalo, Milena; Abenhaim, Haim A

    2012-06-01

    The optimal timing for cord clamping, early versus delayed, in the third stage of labour is a controversial subject. Issues surrounding the timing of cord clamping include gestational age and maternal and neonatal considerations. Delayed cord clamping (DCC) has been shown to increase placental transfusion, leading to an increase in neonatal blood volume at birth of approximately 30%. In the term infant, although this may result in an increase in iron stores, thereby decreasing the risk of anemia, it may adversely increase the risk of jaundice and the need for phototherapy. In the preterm infant, DCC (or even milking of the cord) decreases the need for blood transfusions for anemia, the number of such transfusions, and the risks of intraventricular hemorrhage and late-onset sepsis. Advantages of DCC also include a reduction in alloimmunization in Rh-negative women, although this advantage is theoretical and unproven. We searched multiple databases including PubMed Clinical Queries, Trip Database, Cochrane Systematic Reviews, and UpToDate, as well as published guidelines from the Society of Obstetricians and Gynaecologists of Canada, the American Congress of Obstetricians and Gynecologists, and the Royal College of Obstetricians and Gynaecologists. We preferentially selected systematic reviews and randomized controlled trials for this literature review. Overall, the available evidence appears to suggest that DCC is likely to result in better neonatal outcomes in both term and preterm infants, even in areas where neonatal iron deficiency anemia is rare. However, there is insufficient evidence to date to support a recommendation to delay cord clamping in non-vigorous infants requiring resuscitation.

  18. MATLAB-based automated patch-clamp system for awake behaving mice

    OpenAIRE

    Desai, Niraj S.; Siegel, Jennifer J.; Taylor, William; Chitwood, Raymond A.; Johnston, Daniel

    2015-01-01

    Automation has been an important part of biomedical research for decades, and the use of automated and robotic systems is now standard for such tasks as DNA sequencing, microfluidics, and high-throughput screening. Recently, Kodandaramaiah and colleagues (Nat Methods 9: 585–587, 2012) demonstrated, using anesthetized animals, the feasibility of automating blind patch-clamp recordings in vivo. Blind patch is a good target for automation because it is a complex yet highly stereotyped process th...

  19. Diode-clamped multilevel converters with integrable gate-driver power-supply circuits

    OpenAIRE

    Busquets Monge, Sergio; Rocabert Delgado, Joan; Crébier, Jean-Christophe; Peracaula Roura, Joan

    2009-01-01

    International audience; Recent contributions in pulse width modulations (PWM) for multilevel diode-clamped converters enable the use of these converters with passive front-ends, any number of levels, and small dc-link capacitors. Highly compact converters designs based on these topologies can be envisioned. However, the design of the gate-driver power-supply for the multiple controlled semiconductor devices remains an important issue to be addressed. This paper focuses on the design of such c...

  20. New device for saphenous vein-to-aorta proximal anastomosis without side-clamping

    Directory of Open Access Journals (Sweden)

    Tappainer Ernesto

    2007-05-01

    Full Text Available Abstract Background Side clamping to perform saphenous vein-to-aorta proximal anastomosis is a well known cause of cerebral embolization during coronary bypass surgery. Automatic and manual devices have been introduced to avoid aortic clamping and facilitate proximal anastomosis but the manual ones only allow the traditional hand-sewing running suture. Nevertheless, they are not easy to use and very expensive to buy. Methods We developed a simple object that helps to perform a manual proximal anastomosis without the need to clamp the side of the aorta. This device is a steel bar which blocks the aortic hole and simultaneously it provides a slit to receive the needle. Through the slit comes out a thin, sharp, straight, but also well directed and predictable jet of blood which could be easily controlled during the suture. Results The function of the object is quite different from other devices. Nothing is deployed in the aorta. The object is only placed on the aorta with the small appendage slipped into the hole. The main advantage of the device is that while manipulation of the aorta is avoided no foreign bodies are incorporated in the suture and – most importantly – the aortic intima is not touched at all. The main drawback of the device is the blood jet coming from the slit so that the blood pressure has to be lowered by vasodilators during the anastomosis. Moreover, the suture has to change direction and the needle has to enter the aortic wall first to slip out through the slit. Conclusion The object was named "Slit Device" and is not a routine instrument. It would be only an alternative to other anastomotic devices with the same surgical indications. In the case of ascending aortic disease and saphenous vein grafting, the Slit Device avoids aortic clamping thereby preventing atheroembolism and also avoiding the need for hypothermic circulatory arrest in patients with unclampable aorta.