Real-Time High Resolution Integrated Optical Micro-Spectrometer

A real-time integrated planar single-mode waveguide grating micro-spectrometer with high resolution of 0.5 nm in 120 nm wide range of visible spectrum, from 525 nm to 645 nm is demonstrated. A CMOS sensor is used for capturing the output image of micro-spectrometer. A f = 1cm lens is used to focus the diffracted monochromatic light onto the CMOS sensor. An algorithm is developed using simple polynomial equation which uses two known reference wavelengths to convert x-pixel numbers of the CMOS sensor to wavelength spectrum. The output of micro-spectrometer in this design has comparatively less noise than usual spectrometric measurements. This design uses built-in matlab functions such as \u27findpeaks\u27 to find the input laser peaks and the central pixel numbers for that peaks and \u27polyfit\u27 to find the coefficients essential for the calibration of wavelength spectrum

Vector Spaces for Multiple Modal Embeddings

Deep learning has enabled great advances in the field of natural language processing, computer vision and pattern recognition in general. Deep learning frameworks have been very successful in performing classification, object detection, segmentation and translation. Before objects can be processed, a vector representation of that object needs to be created. For example, sentences and images can be encoded with a sent2vec and image2vec function respectively in preparation for input to a machine learning framework. Neural networks are able to learn efficient vector representation of images, text, audio, videos and 3D point clouds. However, the transfer of knowledge from one modality to the other is a challenging task. In this work, we develop vector spaces that can handle data that belongs to multiple modalities at the same time. In these spaces, similar objects are tightly clustered and dissimilar objects are far away irrespective of their modality. Such a vector space can be used in retrieval of objects, searching and generation tasks. For example, given a picture of a person surfing, one can retrieve sentences or audio bites of a person surfing. We build a Multi-stage Common Vector Space (M-CVS) and Reference Vector Space (RVS) that can handle images, text, audios, videos and 3D point cloud data. Both, the M-CVS and RVS can handle the addition of a new modality without having to change the existing transforms or architecture. Our model is evaluated by performing cross modal retrieval on multiple benchmark datasets

Dense Periodical Patterns In Photonic Devices: Technology For Fabrication And Device Performance

For the fabrication, focused ion beam parameters are investigated to successfully fabricate dense periodical patterns, such as gratings, on hard transition metal nitride such as zirconium nitride. Transition metal nitrides such as titanium nitride and zirconium nitride have recently been studied as alternative materials for plasmonic devices because of its plasmonic resonance in the visible and near-infrared ranges, material strength, CMOS compatibility and optical properties resembling gold. Coupling of light on the surface of these materials using sub-micrometer gratings gives additional capabilities for wider applications. Here we report the fabrication of gratings on the surface of zirconium nitride using gallium ion 30keV dual beam focused ion beam. Scanning electron microscope imaging and atomic force microscope profiling is used to characterize the fabricated gratings. Appropriate values for FIB parameters such as ion beam current, magnification, dwell time and milling rate are found for successful milling of dense patterns on zirconium nitride. For the device performance, a real-time image-processing algorithm is developed to enhance the sensitivity of an optical miniature spectrometer. The novel approach in this design is the use of real-time image-processing algorithm to average the image intensity along the arc shaped images registered by the monochromatic inputs on the CMOS image sensor. This approach helps to collect light from the entire arc and thus enhances the sensitivity of the device. The algorithm is developed using SiTiO2 planar waveguide. The accuracy of the mapping from x-pixel number scale of the CMOS image sensor to the wavelength spectra of the miniature spectrometer is demonstrated by measuring the spectrum of a known LED source using a conventional desktop spectrometer and comparing it with the spectrum measured by the miniature spectrometer. The sensitivity of miniature spectrometer is demonstrated using two methods. In the first method, the input laser power is attenuated to 0.1 nW and the spectra is measured using the miniature spectrometer. Even at low input power of 0.1nW, the spectrum of monochromatic inputs is observed well above the noise level. Second method is by quantitative analysis, which measures the absorption of CdSeS/ZnS quantum dots drop casted between the gratings of Ta2O5 planar single-mode waveguide. The expected guided mode attenuation introduced by monolayer of quantum dots is found to be approximately 11 times above the highest noise level from the absorption measurements. Thus, the miniature spectrometer is capable of detecting the signal from the noise level even with the absorption introduced by monolayer of quantum dots

Comparison of Rift Valley fever virus replication in North American livestock and wildlife cell lines

Citation: Gaudreault, N. N., Indran, S. V., Bryant, P. K., Richt, J. A., & Wilson, W. C. (2015). Comparison of Rift Valley fever virus replication in North American livestock and wildlife cell lines. Frontiers in Microbiology, 6(JUN). doi:10.3389/fmicb.2015.00664Rift Valley fever virus (RVFV) causes disease outbreaks across Africa and the Arabian Peninsula, resulting in high morbidity and mortality among young domestic livestock, frequent abortions in pregnant animals, and potentially severe or fatal disease in humans. The possibility of RVFV spreading to the United States or other countries worldwide is of significant concern to animal and public health, livestock production, and trade. The mechanism for persistence of RVFV during inter-epidemic periods may be through mosquito transovarial transmission and/or by means of a wildlife reservoir. Field investigations in endemic areas and previous in vivo studies have demonstrated that RVFV can infect a wide range of animals, including indigenous wild ruminants of Africa. Yet no predominant wildlife reservoir has been identified, and gaps in our knowledge of RVFV permissive hosts still remain. In North America, domestic goats, sheep, and cattle are susceptible hosts for RVFV and several competent vectors exist. Wild ruminants such as deer might serve as a virus reservoir and given their abundance, wide distribution, and overlap with livestock farms and human populated areas could represent an important risk factor. The objective of this study was to assess a variety of cell lines derived from North American livestock and wildlife for susceptibility and permissiveness to RVFV. Results of this study suggest that RVFV could potentially replicate in native deer species such as white-tailed deer, and possibly a wide range of non-ruminant animals. This work serves to guide and support future animal model studies and risk model assessment regarding this high-consequence zoonotic pathogen. © 2015 Gaudreault, Indran, Bryant, Richt and Wilson

A Study of Prevalence of Noise Induced Hearing Loss in Auto Drivers

Noise is one of the occupational health disorders affecting workers in various professions. Traffic noise is a one of the source of environmental pollution in developed and developing nations. Recent reports suggest that, outside Europe and North America, up to 25% of adult males of working age have evidence of occupational noise induced hearing loss. This seems to be a particular problem in those countries moving from agriculture to a stronger manufacturing base for their developing economies. Noise induced hearing loss refers to exposure of loud sounds beyond 85db over a period of time. Sounds of 130 dB (A) or greater will cause hearing damage after even short time periods in almost all exposed individuals. noise induced hearing loss is preventable through early intervention. There is evidence that the use of hearing protection reduces the risk of noise induced hearing loss from noise in both recreational and occupational contexts. As regards hearing protection, the choice is between earplugs, earmuffs earplugs can be assumed to give approximately 10–15 dB of sound attenuation and earmuffs at least 15 dB and active noise reduction early detection of noise induced hearing loss can be made by use of pure tone audiometry

A Study on Thyroid Function Tests in Decompensated Liver Disease and Implication of Serum Free T3 as a Prognostic Indicator

BACKGROUND: The liver plays a major role in metabolism of thyroid hormone by their conjugation, excretion, peripheral deiodination and in synthesis of thyroxine binding globulin. Although almost all patients of decompensated liver disease appear clinically euthyroid, abnormalities in circulating thyroid hormones have been shown in studies. Studies confirm that serum T3 concentrations parallel the severity of liver dysfunction. OBJECTIVE: To do Thyroid function tests in patients with decompensated chronic liver disease and to determine the importance of serum Free T3 as a prognostic indicator. METHOD: A prospective study was conducted with a sample of 60 patients admitted to the wards of Institute of Internal Medicine, RGGGH with a diagnosis of decompensated chronic liver disease. The duration of the study was six months. Child Pugh scores of the patients were calculated. Thyroid function tests were done in the patients and the results were analysed for statistical significance of serum free T3 levels as a prognostic indicator. RESULTS: The Pearson correlation coefficient was applied for Child Pugh scores and serum free T3 levels which was found to be -0.964 with a P value of < 0.01. The statistical analysis of the data showed that a significant association exists between the Child Pugh score and serum free T3 levels in patients with decompensated chronic liver disease. CONCLUSION: The value of serum free T3 levels decreases proportionately as the Child Pugh score increases thus validating the role of measuring serum free T3 levels in patients with chronic liver disease and using it to assess prognosis with various levels of decompensation

Prediction of thyroid malignancy based on clinical, radiological and biochemical factors with emphasis on serum TSH.

Many patients present to the surgical department with a thyroid nodule. However not all require surgery and only 5-6% of these are malignant. There are many methods to diagnose and predict malignancy in a thyroid nodule. This study throws light on the usefulness of clinical, radiological and TSH estimation and its role in predicting malignancy. There is a definite relationship between higher TSH levels and malignancy. TSH levels could be used as predictor in clinically suspicious malignant thyroid swelling with a benign FNAC report. In such cases where TSH value is high, the FNAC can be relooked to confirm the diagnosis. In addition to TSH, clinical features such as lymphadenopathy, fixity, SNT, USG features such as hypoechoic, calcification, invasion to adjacent structures are also predictors of thyroid malignancy