Functionalized nanomaterials and their biological applications

Bionanomaterials have been used in drug delivery, cancer therapy and biodiagnosis of pathogens based on their size and surface functionalization. In this present work, different kinds of nanoparticles (NPs), their cellular interactions, cytotoxicity profiles, and finally role of gold nanoparticles (GNPs) in biodetection of E. coli was investigated. Firstly, cytotoxicity profiles of commercial, laser ablation, and green synthetic NPs were studied. Induction of apoptosis in cancer cells was found to be size dependent. The plain 80 nm GNPs and AgNPs enhanced toxic effects in cancer cells when compared to 20 nm ones. Apoptotic profiles of ALB- or FBS-coated NPs were significantly low in cancer cells when compared to plain NPs. The FBS-coated NPs were relatively bigger. Whereas, green synthetic NPs prepared from floral extracts of Tacoma stans and Tagetus erecta caused significant increase in cell membrane damage in cancer cells when compared to commercial GNPs. The phytochemicals in the extract were found to have a synergistic effect on pathogens like E. coli, Staphylococcus aureus and Enterococcus faecalis when used with antibiotics like tetracycline, ampicillin and vancomycin. This effect can be capitalized in developing NPs as effective drug carriers. Next, use of commercial GNPs as diagnostic tools to detect competitive binding in DU-145 in the presence of UTI-causing E. coli ORN178 was studied. GNPs functionalized with D-mannose (Mn) showed competitive binding between Mn-GNPs and E. coli ORN178 when presented together with DU-145 cells. Cytotoxicity assays of plain and Mn-GNPs showed significant decrease in viability of DU-145 cells. The plain/Mn 20 nm GNPs were taken up more by the cell when compared to the 200 nm ones. The protein-coated GNPs were found to be stable in culture medium. This competitive binding can be further developed to prevent/detect recurrent UTI in DU-45 cells. Lastly, primary and fine sugar specificity of fimbrial lectins of E.coli ORN178 and E. coli 13762 to D-mannose and Neuαc(α2-3)-Gal-(β1-4)Glc-Paa functionalized GNPs showed that E. coli ORN178 binds specifically only to Mn-GNPs and E. coli 13762 to the latter. Hence, adhesin-specific adhesion shows great potential for designing NPs to specifically bind to microorganisms as biodiagnostic tools

Context-aware Captions from Context-agnostic Supervision

We introduce an inference technique to produce discriminative context-aware image captions (captions that describe differences between images or visual concepts) using only generic context-agnostic training data (captions that describe a concept or an image in isolation). For example, given images and captions of "siamese cat" and "tiger cat", we generate language that describes the "siamese cat" in a way that distinguishes it from "tiger cat". Our key novelty is that we show how to do joint inference over a language model that is context-agnostic and a listener which distinguishes closely-related concepts. We first apply our technique to a justification task, namely to describe why an image contains a particular fine-grained category as opposed to another closely-related category of the CUB-200-2011 dataset. We then study discriminative image captioning to generate language that uniquely refers to one of two semantically-similar images in the COCO dataset. Evaluations with discriminative ground truth for justification and human studies for discriminative image captioning reveal that our approach outperforms baseline generative and speaker-listener approaches for discrimination.Comment: Accepted to CVPR 2017 (Spotlight

Real-time video compression using DVQ and suffix trees

Video processing is a wide and varied subject area. Video compression is an important but difficult problem in video processing. Several methods and standards exist which address this problem with varying degrees of success depending on the performance measures adopted. The present research work focuses on the real-time aspect of video processing.;In particular we propose a real-time video compression algorithm based on the concept of differential vector quantization and the suffix tree. Differential vector quantization is a relatively new area that focuses on efficient compression of data. The present work integrates the compression provided by Differential vector Quantization and the speed achieved by using the suffix tree data structure to develop a new real-time video compression scheme.;Traditionally Suffix trees are used for string searching. In the present work, we exploit the unique structure of the suffix tree to represent image data on a tree as a DVQ dictionary. To support the special characteristics of natural images and video, the traditional suffix tree is extended to handle k-errors in the matching. The result is an orders of magnitude speedup in the matching process, making it possible to compress the video in real-time, without any special hardware.;Experimental results show the performance of the proposed methodology

Severity of Spinal Cord Injury Influences Diffusion Tensor Imaging of the Brain

Background: The purpose of this study was to determine whether DTI changes in the brain induced by a thoracic spinal cord injury are sensitive to varying severity of spinal contusion in rats. Methods: A control, mild, moderate, or severe contusion injury was administered over the eighth thoracic vertebral level in 32 Sprague-Dawley rats. At 11 weeks postinjury, ex vivo DTI of the brain was performed on a 9.4T Bruker scanner using a pulsed gradient spin-echo sequence. Results: Mean water diffusion in the internal capsule regions of the brain and pyramid locations of the brainstem were correlated with motor function (r2 = 0.55). Additionally, there were significant differences between injury severity groups for mean diffusivity and fractional anisotropy at regions associated with the corticospinal tract (P = 0.05). Conclusion: These results indicate that DTI is sensitive to changes in brain tissue as a consequence of thoracic SCI