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Register a new userThe Effects of C.W. He-Ne Laser Brightness on the Eye Retina of Lacerta laevis
التعرف على تأثير ليزر الهليوم – نيون المستمر في شبكية عين العظاء Lacerta laevis
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يهدف هذا البحث إلى اختبار أثر السطوع الليزري في شبكية عين العظاء، و مدى التغير الحاصل بالتشوه أو الأذى في بنية خلايا الاستقبال الضوئي المسؤولة عن عملية الرؤية، أو في الطبقة الظهارية الصباغية الواقية من الشدات الضوئية العالية. توضح نتائج الدراسة بجلاء الأثر التخريبي و التفككي في خلايا الإحساس الضوئي (المخاريط) في الشبكية، مما يضعف المقدرة على الإبصار. كما أن الاستمرار سفي التعرض يؤدي إلى تزايد عدد الخلايا المتأذية لينتهي الأمر بفقدان كامل طبقة المستقبلات الضوئية، و هذه النتائج أتت متوافقة مع الأبحاث التي درست تأثير السطوع الليزري في شبكية عين الثدييات. كما يتبين من هذه الدراسة أن التعرض غير المباشر (عند الانعكاس المرآتي) يلحق الأذى بشكل ملموس في شبكية العين عند العظاء، و هذا يتفق مع الدراسات السابقة، الأمر الذي أشار إلى وجود تشابه بين الرؤية لدى الزواحف و الثديات، بخاصة في نطاق تمييز الألوان الرئيسة.
The aim of this paper is to test the influence of the laser brightness on the retina of eye of lacerta laevis, and the value of the distortion or damage in the construction of photoreceptors (Cones), which are responsible of the viewing process or in the pigmentary epithelial layer which protect from the high light intensity. On the other hand, the continuation of the exposure to the He- Ne laser beam the number of the damaged cells, that causes the loss of entire photoreceptor layer. The results show similar effects at specular reflection. Hence, it is very important to pay attention to the hazard emerged from the laser beam in visible range, which requires to apply the special goggles, as well as to keep the laser pointers out of reach of children.
References used
القطب، زياد. الفيزيولوجيا المقارنة، منشورات جامعة دمشق. ١٩٨٦
المصري، عروب. دراسة تصنيفية وبيئية للعظايا في بعض مناطق جنوب سورية. رسالة مقدمة لنيل . درجة الماجستير – جامعة دمشق 1997
د. كوران. د. كور، ك. شفانبرع – س. شفانبرغ، الليزر في الطب، مقالة مترجمة – مجلة عالم الذرة – .(١٩٩٦) . هيئة الطاقة الذرية السورية – العدد ٤٥
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Our results assured the presence of functional association between the
pigment epithelium (P.E) and photoreceptors of eye retina of lacerta laevis. The
continuous effect of He-Ne laser on eye produce dangerous structure changes
(according to studi
es by transmission electron microscope) led to damage of
parts and organelles of pigment epithelium and photoreceptors of eye retina.
The displacement of the epithelium from the photoreceptors layer was the first
dangerous results on vision (Retinal detachment). This detachment conduced to
no protection of photoreceptors from high intense light (which usually
maintained by melanin pigments spread in epithelium cells surrounding the
outer segments [O.S] of photoreceptors) so that the outer segments of
photoreceptor became under the influence of intense light of He-Ne laser which
conduced to damage of cytoplasmic membrane of outer segment disks and
damage of chemical structure of visual pigments (pigment necessary for
discrimination of color in cones) so the photo sensible pole lost its function in
transferring the sign of light necessary for vision. The lesion happened by the
influence of He-Ne laser in the cones, associated by dangerous changes in the
retardation of nucleus size and damage of chromatin material and the absence
of organelles responsible for biological synthesis of cellular protein, and
deconstruction of glycogen molecules (energy mols.). The most dangerous thing
is the resulted damage of synaptic pedicle of cones (lost of connection between
bipolar nerve cells and synaptic ribbons) so the neurotransmission pole lost its
function in neurotransmission across the layer of neurosynapsis of retina. The
damaged photoreceptor cells (cones) (which were almost dead) became disables
to do their function in vision.
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Ne Laser, with testing some blood characteristics like osmotic fragility,
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we seek to ensure laser stability , during its work , with time , and consistency of specifications and efficiency (returns), the cooling of the active medium and optical elements, are sensitive to the proper cooling method, in economic terms and in
terms ease of work.
Cooling technique helps prolonging the life of laser systems ,its stability and optimizing its operation. So the total cooling efficient lasers , Scientific and Industrial is essential when designing a laser and helps improving the specifications of lasers , gaseous or solid or semiconductor . In addition to that cooling has a good impact on the age of the laser , and safety of its use .
The designed cooling system , necessary for a certain laser system , depends on the amount of heat generated from the system(in Joule), which must be removed by the cooling system to keep the laser at specific temperature
Lexical complexity is a highly subjective notion, yet this factor is often neglected in lexical simplification and readability systems which use a ''one-size-fits-all'' approach. In this paper, we investigate which aspects contribute to the notion of
lexical complexity in various groups of readers, focusing on native and non-native speakers of English, and how the notion of complexity changes depending on the proficiency level of a non-native reader. To facilitate reproducibility of our approach and foster further research into these aspects, we release a dataset of complex words annotated by readers with different backgrounds.
This paper proposes a new approach for the segmentation of the retina images to obtain the optic nerve and blood vessels regions. We used retinal images from DRIVE and STARE databases which include different situations like illumination variations, d
ifferent optic nerve positions (left, right and center). Illumination problem has been solved by preprocessing stage including image histogram-based illumination correction. Next, some morphological operations were used to filter the preprocessed image to obtain the ROI region, then, the center and radius of optic nerve were determined, and the optic nerve region was extracted from the original image. In blood vessels segmentation, we applied the illumination correction and median filtering.Then the closing, subtraction and morphological operations were done to get the blood vessels image which was thresholded and thinned to get the final blood vessels image.
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