Spatially selective narrow band and broadband absorption in Ag/SiO2/Ag based trilayer thin films by oblique angle deposition of SiO2layer.

We have experimentally demonstrated spatially selective absorption in Ag-SiO2-Ag based trilayer thin films by tuning the deposition angle of SiO2layer. These structures generate cavity resonance which can be tuned across the substrate locations due to spatially selective thickness and refractive index of silicon oxide (SiO2) film sandwiched between metallic silver (Ag) mirrors. Spatially selective property of SiO2film is obtained by oblique angle deposition technique using an electron beam evaporation system. The resonance wavelength of absorption in this trilayer structure shifts across the substrate locations along the direction of oblique deposition. The extent of shift in resonance increases with increase in angle of deposition of SiO2layer. 4.14 nm mm-1average shift of resonance wavelength is observed when SiO2is deposited at 40° whereas 4.76 nm mm-1average shift is observed when SiO2is deposited at 60°. We observed that the width of resonance increases with angle of deposition of the cavity layer and ultimately the resonant absorption disappears and becomes broadband when SiO2is deposited at glancing angle deposition (GLAD) configuration. Our study reveals that there is a suitable range of oblique angle of deposition from 40° to 60° for higher spatial tunability and resonant absorption whereas the absorption becomes broadband for glancing angle deposition.

Comparative Study on Insall-Salvati Index by Radiological and Clinical Methods in a Tertiary Care Centre of North Bengal, India.

INTRODUCTION: Patellar height is an important parameter of patellar stability. Its importance is evident from various attempts to measure it, by different scientists from time to time and many indices have been derived among which Insall-Salvati index (IS index) is the most simple, accurate and easy to measure. In this study a new clinical method has been tried to measure patellar height by applying the same principle of IS index. AIM: To compare clinical method of measurement of IS index with the one derived radiologically and to establish the higher cut off value of the clinical method. MATERIALS AND METHODS: In the present study 186 knee joints (93 subjects) were subjected to measurement of patellar height by both clinical and radiological methods. The IS index was measured bilaterally from lateral view of X-ray plates and it was measured clinically in every knee joint. Both the values were compared using students t-test and higher cut off values were set for normal knee joint for the clinical method. RESULTS: Among 93 study participants majority were females (54.83%), age of the patients varied from 10-68 years with mean age of 28 years and Standard deviation (SD) of 16.4. It was found that, there was no statistically significant difference between the mean values obtained by clinical method of measurement, compared to conventional one (IS Index) for both the genders and age groups on both the sides. A cut off value of 0.98 cm by clinical method gives sensitivity of 80% and specificity of 36% with area under the ROC curve 0.596. CONCLUSION: The subjects with patellar height of less than cut off value by clinical method can avoid radiological investigation as there was no statistically significant difference of IS index between radiological and clinical methods.

Early Clinical Exposure as a Learning Tool to Teach Neuroanatomy for First Year MBBS Students.

CONTEXT: Early clinical exposure (ECE) is one of the important tools to teach basic science to the MBBS students. It is one form of vertical integration between basic science and clinical subjects. This study is an effort at exploring the use of ECE as a motivational tool toward better learning in neuroanatomy for first year MBBS students. AIM: This study aims to make the students interested and motivated to study neuroanatomy by using ECE as learning tool in neuroanatomy and to make the students enable to retain the knowledge of neuroanatomy more efficiently and correlate the knowledge of neuroanatomy with neuromedicine. SETTINGS AND DESIGN: This study was conducted in collaboration with the Departments of Anatomy, General Medicine and Medical Education Unit in the year 2016. This was cross-sectional study. SUBJECTS AND METHODS: One hundred and fifty students of 1st Professional MBBS were subdivided into two groups. After preliminary classes on brain, brainstem, and spinal cord for both groups, conventional lecture classes were taken for Group A only on upper motor neuron (UMN) and lower motor neuron (LMN) paralysis, and only Group B visited General Medicine ward where HOD, General Medicine showed and examined patients of UMN paralysis and LMN paralysis, elicited different symptoms, and discussed different investigation. It was followed by assessment of all by problem-based multiple choice questions (MCQ) and short answer questions. Then, Group B attended lecture class on different cranial nerve palsy whereas Group A visited medicine ward. It was followed by assessment of both groups by problem-based MCQ and short answer questions. The performance was compared. Then, the feedback of the students on ECE was collected by means of reflection writing followed by administration of questionnaire. Then, the perception of teachers regarding ECE was recorded by focused group discussion. STATISTICAL ANALYSIS USED: Student's t-test was used to compare the performance of both batches. Reflection writing and focus group discussion were analyzed qualitatively. RESULTS: There was a significant difference in Group A (P = 0.019) but no significant difference in Group B (P = 0.679). All the teachers opined that ECE was an efficient method but more time and interdepartmental collaboration were necessary. CONCLUSIONS: Group A improved performance due to ECE but Group B maintained the motivational effect of it. Therefore, ECE can be used as an effective learning tool.

Variation of Axial Ocular Dimensions with Age, Sex, Height, BMI-and Their Relation to Refractive Status.

BACKGROUND: Myopia is one of the most common causes of visual impairment worldwide.It is proved in earlier studies that the eye shape is different in myopic and nonmyopic children even at a very young age, with the former manifesting asymmetric axial globe elongation and the latter global expansion but limited information is available regarding hypermetropia. AIM: To find out the variations of axial ocular dimensions in relation to age, sex, height and to demonstrate any possible correlation of body mass index (BMI) in myopic hypermetropic and emmetropic patients. SETTINGS: It is a cross-sectional observational study. MATERIALS AND METHODS: All the patients attending eye OPD in the Regional Institute of Ophthalmology (R.I.O.), Medical College, Kolkata, West Bengal, India from June2010 to May 2011.Axial dimensions were measured by B-mode USG. Refractive status was measured.Age, gender, height and BMI were also observed. After collecting all the data,all the variables were summarised by descriptive statistics followed by correlation testing by Pearson's Correlation Coefficient r. RESULTS: Height was positively correlated with axial length, anterior chamber depth, vitreous chamber depth ;age was positively correlated with axial length, vitreous chamber depth and negatively correlated with anterior chamber depth. Subjects with higher BMI tended to had refractions that were more hypermetropic. CONCLUSION: The findings of the present study can highlight not only the normal range of the different ocular parameters namely axial length, anterior chamber depth, vitreous chamber depth and lens thickness but their variation with age, gender, height and weight.

Change of patellar height with age and sex.

Patellar height is one of the important parameter in patellar stability. Growth spurt or excessive physical strain can lead to high-riding patella or patella alta. But this is not yet proved. This study was mainly targeted at eliciting the influence of age on Insall-Salvati index, one of the important index to measure patellar height. As the present study is meant for measuring the patellar height separately in male and female, it is also to find out the effect of gender on patellar height if any. The study was been conducted in North Bengal Medical College and Hospital among 93 subjects covering both adult and adolescent age groups. Patellar height of respective subjects was measured radiologically using Insall-Salvati Index; results were extrapolated for statistical analysis. It revealed that value of Insall-Salvati index was higher in adult compared to adolescent group but the difference was not statistically significant. Statistical tests shows no significant difference in Insall-Salvati index according to sex. While screening the athletes patella alta must be kept in mind as this can be associated with patellofemoral pain syndrome, chondromalacia patellae, knees with apophysitis of tibial tubercle (Osgood-Schiatter disease). Not only that, significant cause of recurrent patellar dislocation can be associated with patella alta