Stability indicating HPTLC method for quantitative estimation of manidipine sihydrochloride API

A simple, selective, precise and stability indicating high performance thin layer chromatographic method has been established and validated for analysis of manidipine hydrochloride in bulk. The compound was analyzed on aluminium backed silica gel 60 F254 plates with methanol:water, 8.5:1.5 (v:v) as mobile phase. The system was found to give compact spots for manidipine dihydrochloride (RF=0.75). Densitometric analysis was performed at 230 nm. Regression analysis data for the calibration plot indicated good linear relationships between response and concentration over the range of 500-3000 ng/spot. The correlation coefficient, r2 was 0.998. The values of slope and intercept of the calibration plot were 2785.5 and 62.314, respectively. The method was validated for precision, recovery and robustness. The limits of detection and quantification were 20 and 50 ng, respectively. Manidipine dihydrochloride was subjected to acid, base, peroxide and sunlight induced degradation. In stability test the drug was susceptible to acid and base hydrolysis, oxidation and photodegradation. Statistical analysis proved that the method is repeatable, selective and accurate for manidipine. Because the method could effectively separate the drug from their degradation products, it can be used as a stability indicating method

A Visual Guide to Essay Writing

Dr Valli Rao, Associate Professor Kate Chanock, and Dr Lakshmi Krishnan use a visual approach to walk students through the most important processes in essay writing for university: formulating, refining, and expressing academic argument

On Locally Decodable Index Codes

Index coding achieves bandwidth savings by jointly encoding the messages demanded by all the clients in a broadcast channel. The encoding is performed in such a way that each client can retrieve its demanded message from its side information and the broadcast codeword. In general, in order to decode its demanded message symbol, a receiver may have to observe the entire transmitted codeword. Querying or downloading the codeword symbols might involve costs to a client -- such as network utilization costs and storage requirements for the queried symbols to perform decoding. In traditional index coding solutions, this 'client aware' perspective is not considered during code design. As a result, for these codes, the number of codeword symbols queried by a client per decoded message symbol, which we refer to as 'locality', could be large. In this paper, considering locality as a cost parameter, we view index coding as a trade-off between the achievable broadcast rate (codeword length normalized by the message length) and locality, where the objective is to minimize the broadcast rate for a given value of locality and vice versa. We show that the smallest possible locality for any index coding problem is 1, and that the optimal index coding solution with locality 1 is the coding scheme based on fractional coloring of the interference graph. We propose index coding schemes with small locality by covering the side information graph using acyclic subgraphs and subgraphs with small minrank. We also show how locality can be accounted for in conventional partition multicast and cycle covering solutions to index coding. Finally, applying these new techniques, we characterize the locality-broadcast rate trade-off of the index coding problem whose side information graph is the directed 3-cycle.Comment: 10 pages, 1 figur

Neuromorphic model for sound source segregation

While humans can easily segregate and track a speaker's voice in a loud noisy environment, most modern speech recognition systems still perform poorly in loud background noise. The computational principles behind auditory source segregation in humans is not yet fully understood. In this dissertation, we develop a computational model for source segregation inspired by auditory processing in the brain. To support the key principles behind the computational model, we conduct a series of electro-encephalography experiments using both simple tone-based stimuli and more natural speech stimulus. Most source segregation algorithms utilize some form of prior information about the target speaker or use more than one simultaneous recording of the noisy speech mixtures. Other methods develop models on the noise characteristics. Source segregation of simultaneous speech mixtures with a single microphone recording and no knowledge of the target speaker is still a challenge. Using the principle of temporal coherence, we develop a novel computational model that exploits the difference in the temporal evolution of features that belong to different sources to perform unsupervised monaural source segregation. While using no prior information about the target speaker, this method can gracefully incorporate knowledge about the target speaker to further enhance the segregation.Through a series of EEG experiments we collect neurological evidence to support the principle behind the model. Aside from its unusual structure and computational innovations, the proposed model provides testable hypotheses of the physiological mechanisms of the remarkable perceptual ability of humans to segregate acoustic sources, and of its psychophysical manifestations in navigating complex sensory environments. Results from EEG experiments provide further insights into the assumptions behind the model and provide motivation for future single unit studies that can provide more direct evidence for the principle of temporal coherence

Effectiveness of Two Sensory Based Health Education Methods on Oral Hygiene of Children with Autism Spectrum Disorders: An Interventional study

BACKGROUND: Improper tooth-brushing leads to poor oral hygiene, in turn causes diseases, such as chronic gingivitis and caries which are considered as major public health problem. This scenario has worsened among children of special populations such as disabled people especially Autism spectrum disorder (ASD). Children with ASD suffer from sensorimotor problems, improper communication and social skills. Hence it is the obligation of dental professional to adopt techniques to reduce their problems and teach them about proper method of tooth brushing. Over the years, applied behavioural analysis has proved to be effective in bringing behavioural changes to these children. Hence this study was developed to assess the effectiveness of two sensory based interventions namely – Visual pedagogy and Mobile based application (Brush Up™) on oral health education in promoting oral health status among 13 to 17 year old school going children with ASD in Chennai city. AIM AND OBJECTIVES: To assess the effectiveness of a mobile application (Brush Up™) based interactive oral health education tutorial, compared to visual cards (Visual pedagogy) 36 on oral health education in promoting oral hygiene among 13 to 17 year old children with mild to moderate autism in Autism spectrum disorder (ASD) among two schools for special children at Chennai city. METHODOLOGY: This Interventional study with two parallel arms was designed to assess the effectiveness of visual pedagogy and mobile application (Brush Up™) among a group of 13 to 17 year old school going children with ASD in Chennai city. Among the children who were screened, ninety students who met the inclusion and exclusion criteria were identified. From this, sixty students who were willing to participate and whose parents signed and returned the consent form were selected and allocated into two groups consisting of thirty subjects in each arm. Visual pedagogy method was given to group A and Mobile application (Brush Up™) was given to group B for a period of 12 weeks. An intra-oral examination was carried to assess the oral health status of the study population. Plaque Index and gingival index were assessed at baseline, 6th week and after 12th week. RESULTS: At baseline examination, the dental plaque index score among the Group A and Group B were 2.02 and 2.01 respectively. At 6 weeks, the post intervention examination the dental plaque score reduced to 1.00 in both the groups. Later in the follow up examination after 12weeks, the dental plaque scores were 0.45 and 0.46 in Group A and Group B. The Gingival index score among the Group A and Group B were 1.05 and 1.03 respectively at the baseline examination. After 6 weeks, post intervention examination, the gingival score reduced to 0.61 and 0.58 in group A and Group B. At 12th week follow up examination, the gingival score were 0.24 and 0.28 for Group A and B respectively. There was no statistically significant difference in dental plaque and gingival scores between the groups. CONCLUSION: Both the modalities can be used as an effective tool in educating these children and thus improve their oral hygiene. However, further longitudinal studies should be designed to assess the effectiveness of both the interventions among varied age distribution of children and different severity of ASD

Coded Data Rebalancing: Fundamental Limits and Constructions

Distributed databases often suffer unequal distribution of data among storage nodes, which is known as `data skew'. Data skew arises from a number of causes such as removal of existing storage nodes and addition of new empty nodes to the database. Data skew leads to performance degradations and necessitates `rebalancing' at regular intervals to reduce the amount of skew. We define an r-balanced distributed database as a distributed database in which the storage across the nodes has uniform size, and each bit of the data is replicated in r distinct storage nodes. We consider the problem of designing such balanced databases along with associated rebalancing schemes which maintain the r-balanced property under node removal and addition operations. We present a class of r-balanced databases (parameterized by the number of storage nodes) which have the property of structural invariance, i.e., the databases designed for different number of storage nodes have the same structure. For this class of r-balanced databases, we present rebalancing schemes which use coded transmissions between storage nodes, and characterize their communication loads under node addition and removal. We show that the communication cost incurred to rebalance our distributed database for node addition and removal is optimal, i.e., it achieves the minimum possible cost among all possible balanced distributed databases and rebalancing schemes

Locally Decodable Index Codes

An index code for broadcast channel with receiver side information is locally decodable if each receiver can decode its demand by observing only a subset of the transmitted codeword symbols instead of the entire codeword. Local decodability in index coding is known to reduce receiver complexity, improve user privacy and decrease decoding error probability in wireless fading channels. Conventional index coding solutions assume that the receivers observe the entire codeword, and as a result, for these codes the number of codeword symbols queried by a user per decoded message symbol, which we refer to as locality, could be large. In this paper, we pose the index coding problem as that of minimizing the broadcast rate for a given value of locality (or vice versa) and designing codes that achieve the optimal trade-off between locality and rate. We identify the optimal broadcast rate corresponding to the minimum possible value of locality for all single unicast problems. We present new structural properties of index codes which allow us to characterize the optimal trade-off achieved by: vector linear codes when the side information graph is a directed cycle; and scalar linear codes when the minrank of the side information graph is one less than the order of the problem. We also identify the optimal trade-off among all codes, including non-linear codes, when the side information graph is a directed 3-cycle. Finally, we present techniques to design locally decodable index codes for arbitrary single unicast problems and arbitrary values of locality.Comment: Accepted for publication in the IEEE Transactions on Information Theory. Parts of this manuscript were presented at IEEE ISIT 2018 and IEEE ISIT 2019. This arXiv manuscript subsumes the contents of arXiv:1801.03895 and arXiv:1901.0590