Abstract-Negative refraction has been the subject of considerable interest and it may provide the possibility of a variety of novel applications. It arises in metamaterials that have simultaneous negative permittivity ε and permeability µ, where in-homogeneities are much smaller than the wavelength of the incoming radiation. Recently it has been shown that photonic crystals (PCs) may also exhibit negative refraction although they have a periodically modulated positive permittivity ε and permeability µ. We have theoretically studied the negative refraction in one-dimensional (1D) photonic crystals (PCs) consisting dielectric ZnSe with air. By using transfer matrix method and block theorem we have studied the photonic band structure and group velocity and with the help of group velocity we have obtained the frequency bands of negative refraction. We found that negative refraction may occur near the low frequency edge of the second and fourth bandgaps. We have also studied the effective index of refraction and the transverse position shift through PC that can characterize negative refraction more explicitly.
Background: The uterus is the vital organ of female reproductive system which holds the fetus during pregnancy. Diseases of uterus has been broadly grouped into inflammatory, benign and malignant lesions. In our study hysterectomy specimens were studied and results were compared with their clinical diagnosis. Primary aim of our study was to correlate the histopathological features of the disease with its clinical diagnosis. Material & Methods: This was a retrospective study and included 277 hysterectomy specimens received over 2 year periods. Patient data was retrieved from the medical records and histopathology requisition form which included age, clinical findings, histopathological diagnosis, indication of hysterectomy and type of hysterectomy done. Histopathological findings from the cervix, endometrium, myometrium, ovaries and fallopian tubes of each and every hysterectomy specimen were noted. Result: A total of 277 cases were analyzed. Patient's age ranged from 16 to 85 years thus included reproductive age group, perimenopausal and post-menopausal women. In our study most common indication for hysterectomy was abnormal uterine bleeding in 33.9 % cases followed by fibroid in 22% cases. The commonest chief complaint was heavy menstrual bleeding in 35.0% cases followed by abdominal pain in 32.5% cases. Majority of the patients were in 36-45year age group. Conclusion: Majority of the hysterectomy cases post-operatively were consistent with the clinical diagnosis, histopathological examination is still the gold standard test to diagnose and rule out malignancy and compulsory for all the surgical specimens.
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