999 research outputs found

    Изучение терапевтических эффектов излучения с длиной волны 670 нм при различных типах диабетического макулярного отека

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    The purpose of this study was to investigate the therapeutic effects of 670 nm irradiation in patients with diabetic macular edema. In several studies, positive effects of red/near-infrared irradiation showed in a range of ocular diseases such as macular degeneration, macular edema, and retinitis pigmentosa. This study was conducted on forty five eyes of 26 diabetic patients with macular edema between the ages of 51 and 80.Measurement of visual acuity and slit lamp examination, funduscopy, and optical coherence tomography were performed in all subjects. None of the patients had proliferative retinopathy. We used a portable LED device (Warp 10, Quantum Devices) for treatment. Patients held this device at a distance of 3 cm from their eyes for 240 seconds for three months. Full ophthalmic examinations were repeated 1, 2, and 3 months after treatment.After 3 months, the mean visual acuity improved from 0.44 ± 0.38 log MAR to 0.27 ± 0.24 log MAR and vision increased by 1.52 ± 1.16 lines post treatment (р<0.001). The mean central macula thickness decreased from 381.49 ± 144.40 μm to 359.72 ± 128.84 μm (р=0.050). In patients with mild and moderate nonproliferative diabetic retinopathy, the mean central retinal thickness decreased 52.06 ± 67.78 μm and 39.27 ± 44.69 μm, respectively, but patients with severe type showed an increase of 34.93 ± 65.65 μm in the mean central retinal thickness (р<0.001). Also, the severity of macular edema had no effect on final outcomes (р>0.05). Photobiomodulation can positively affect diabetic macular edema, especially in patients with mild to moderate diabetic retinopathy.Целью данной исследовательской работы являлось изучение терапевтических эффектов излучения с длиной волны 670 нм у пациентов с диабетическим макулярным отеком. Ряд предыдущих исследований свидетельствует о положительном эффекте красного инфракрасного излучения при некоторых заболеваниях глаз, таких как макулодистрофия (дегенерация желтого пятна), макулярный отек и пигментный ретинит. Наше исследование было проведено на 45 глазах у 26 больных сахарным диабетом в возрасте от 51 до 80 лет с макулярным отеком. Всем пациентам были проведены определение остроты зрения, осмотр глаз щелевой лампой, фундоскопия и оптическая когерентная томография. Ни у одного из пациентов не было пролиферативной ретинопатии. Для лечения нами был применен портативный светодиодный прибор (Warp 10, Quantum devices). Пациенты держали светодиод на расстоянии 3 см от глаза в течение 240 сек в течение 3 мес. Все офтальмологические исследования были повторены через 1, 2 и 3 мес после проведения лечебной процедуры. Через 3 мес средняя острота зрения улучшилась с показателем логарифма минимального угла разрешения 0,44 ± 0,38 до 0,27 ± 0,24, что показало увеличение показателя остроты зрения на 1,52 ± 1,16 после лечения (р<0,001). Средняя центральная толщина сетчатки в области макулы уменьшилась с 381,49 ± 144,40 мкм до 359,72 ± 128,84 мкм (р=0,050). У пациентов с легкой и умеренной непролиферативной диабетической ретинопатией средняя толщина сетчатки уменьшилась до 52,06 ± 67,78 и 52,06 ± 67,78 мкм, соответственно, а у пациентов с тяжелой ретинопатией наблюдалось увеличение на 34,93 ± 65,65 мкм (р<0,001). Помимо того, степень макулярного отека не повлияла на окончательный результат лечения (р>0,05). Фотобиомодуляция была эффективной при диабетическом макулярном отеке, в частности, у пациентов с легкой и умеренной диабетической ретинопатией

    Ichthyotoxism in Capoeta capoeta gracilis (Keyserling, 1861) from west of Urmia (Marmisho Lake), Iran

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    Fish egg poisoning is a public health hazard although usually the incident rate, mortality and fish species involved are not well reported (Halstead,1970). Four species of Cyprinidae in Iran have been suggested as ichthyotoxic by Coad (1979) .namely Abramis brama. Cyprinus carpio .Schizothorax zarudnyi and Tinca tinca and it was thought that other species may be discovered subsequently.Najafpour and Coad (2002) reported ichthyotoxin in the cyprinid Barbus luteus from Iran ,and the study records another species. The Cyprinid fish Capoeta capoeta known as Siah mahi or gara balig in Iran

    Quantum Hall Ferrimagnetism in lateral quantum dot molecules

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    We demonstrate the existance of ferrimagnetic and ferromagnetic phases in a spin phase diagram of coupled lateral quantum dot molecules in the quantum Hall regime. The spin phase diagram is determined from Hartree-Fock Configuration Interaction method as a function of electron numbers N, magnetic field B, Zeeman energy, and tunneling barrier height. The quantum Hall ferrimagnetic phase corresponds to spatially imbalanced spin droplets resulting from strong inter-dot coupling of identical dots. The quantum Hall ferromagnetic phases correspond to ferromagnetic coupling of spin polarization at filling factors between ν=2\nu=2 and ν=1\nu=1.Comment: 4 pages, 4 figure

    Spin transitions induced by a magnetic field in quantum dot molecules

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    We present a theoretical study of magnetic field driven spin transitions of electrons in coupled lateral quantum dot molecules. A detailed numerical study of spin phases of artificial molecules composed of two laterally coupled quantum dots with N=8 electrons is presented as a function of magnetic field, Zeeman energy, and the detuning using real space Hartree-Fock Configuration Interaction (HF-CI) technique. A microscopic picture of quantum Hall ferromagnetic phases corresponding to zero and full spin polarization at filling factors ν=2\nu=2 and ν=1\nu=1, and ferrimagnetic phases resulting from coupling of the two dots, is presented.Comment: 12 pages, 18 figure

    Piezomagnetic Quantum Dots

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    We study the influence of deformations on magnetic ordering in quantum dots doped with magnetic impurities. The reduction of symmetry and the associated deformation from circular to elliptical quantum confinement lead to the formation of piezomagnetic quantum dots. The strength of elliptical deformation can be controlled by the gate voltage to change the magnitude of magnetization, at a fixed number of carriers and in the absence of applied magnetic field. We reveal a reentrant magnetic ordering with the increase of elliptical deformation and suggest that the piezomagnetic quantum dots can be used as nanoscale magnetic switches.Comment: 4 pages, 3 figure

    Elastic Correlations in Nucleosomal DNA Structure

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    The structure of DNA in the nucleosome core particle is studied using an elastic model that incorporates anisotropy in the bending energetics and twist-bend coupling. Using the experimentally determined structure of nucleosomal DNA [T.J. Richmond and C.A. Davey, Nature {\bf 423}, 145 (2003)], it is shown that elastic correlations exist between twist, roll, tilt, and stretching of DNA, as well as the distance between phosphate groups. The twist-bend coupling term is shown to be able to capture these correlations to a large extent, and a fit to the experimental data yields a new estimate of G=25 nm for the value of the twist-bend coupling constant

    Non-contact rack and pinion powered by the lateral Casimir force

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    The lateral Casimir force is employed to propose a design for a potentially wear-proof rack and pinion with no contact, which can be miniaturized to nano-scale. The robustness of the design is studied by exploring the relation between the pinion velocity and the rack velocity in the different domains of the parameter space. The effects of friction and added external load are also examined. It is shown that the device can hold up extremely high velocities, unlike what the general perception of the Casimir force as a weak interaction might suggest.Comment: 4 pages, submitted for publication on 17 Jan 0

    A Simplest Swimmer at Low Reynolds Number: Three Linked Spheres

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    We propose a very simple one-dimensional swimmer consisting of three spheres that are linked by rigid rods whose lengths can change between two values. With a periodic motion in a non-reciprocal fashion, which breaks the time-reversal symmetry as well as the translational symmetry, we show that the model device can swim at low Reynolds number. This model system could be used in constructing molecular-size machines

    Galaxy Zoo: Disentangling the Environmental Dependence of Morphology and Colour

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    We analyze the environmental dependence of galaxy morphology and colour with two-point clustering statistics, using data from the Galaxy Zoo, the largest sample of visually classified morphologies yet compiled, extracted from the Sloan Digital Sky Survey. We present two-point correlation functions of spiral and early-type galaxies, and we quantify the correlation between morphology and environment with marked correlation functions. These yield clear and precise environmental trends across a wide range of scales, analogous to similar measurements with galaxy colours, indicating that the Galaxy Zoo classifications themselves are very precise. We measure morphology marked correlation functions at fixed colour and find that they are relatively weak, with the only residual correlation being that of red galaxies at small scales, indicating a morphology gradient within haloes for red galaxies. At fixed morphology, we find that the environmental dependence of colour remains strong, and these correlations remain for fixed morphology \textit{and} luminosity. An implication of this is that much of the morphology--density relation is due to the relation between colour and density. Our results also have implications for galaxy evolution: the morphological transformation of galaxies is usually accompanied by a colour transformation, but not necessarily vice versa. A spiral galaxy may move onto the red sequence of the colour-magnitude diagram without quickly becoming an early-type. We analyze the significant population of red spiral galaxies, and present evidence that they tend to be located in moderately dense environments and are often satellite galaxies in the outskirts of haloes. Finally, we combine our results to argue that central and satellite galaxies tend to follow different evolutionary paths.Comment: 19 pages, 18 figures. Accepted for publication in MNRA

    Finite Temperature Behavior of the ν=1\nu=1 Quantum Hall Effect in Bilayer Electron Systems

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    An effective field theoretic description of ν=1\nu=1 bilayer electron systems stabilized by Coulomb repulsion in a single wide quantum well is examined using renormalization group techniques. The system is found to undergo a crossover from a low temperature strongly correlated quantum Hall state to a high temperature compressible state. This picture is used to account for the recent experimental observation of an anomalous transition in bilayer electron systems (T. S. Lay, {\em et al.} Phys. Rev. B {\bf 50}, 17725 (1994)). An estimate for the crossover temperature is provided, and it is shown that its dependence on electron density is in reasonable agreement with i the experiment.Comment: Corrected typos, and changed content, 5 pages and 2 figures, accepted in Phys. Rev.
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