525 research outputs found
Symbolic Synchronization and the Detection of Global Properties of Coupled Dynamics from Local Information
We study coupled dynamics on networks using symbolic dynamics. The symbolic
dynamics is defined by dividing the state space into a small number of regions
(typically 2), and considering the relative frequencies of the transitions
between those regions. It turns out that the global qualitative properties of
the coupled dynamics can be classified into three different phases based on the
synchronization of the variables and the homogeneity of the symbolic dynamics.
Of particular interest is the {\it homogeneous unsynchronized phase} where the
coupled dynamics is in a chaotic unsynchronized state, but exhibits (almost)
identical symbolic dynamics at all the nodes in the network. We refer to this
dynamical behaviour as {\it symbolic synchronization}. In this phase, the local
symbolic dynamics of any arbitrarily selected node reflects global properties
of the coupled dynamics, such as qualitative behaviour of the largest Lyapunov
exponent and phase synchronization. This phase depends mainly on the network
architecture, and only to a smaller extent on the local chaotic dynamical
function. We present results for two model dynamics, iterations of the
one-dimensional logistic map and the two-dimensional H\'enon map, as local
dynamical function.Comment: 21 pages, 7 figure
Development of novel carriers for transdermal delivery of peptides
Recent developments in genetic engineering and biotechnology have resulted in anincrease in availability of therapeutic peptides and small anti-cytokines. Oraladministration is inappropriate as these molecules are unstable in the gastrointestinaltract and are subject to hepatic first-pass effect. Transdermal delivery is an attractivealternative as the skin exhibits less enzymatic activity and allows for a controlled,sustained local therapeutic drug concentration over a prolonged period of time.However, the skin’s lipophilic stratum corneum acts as a major barrier to thedelivery of hydrophilic molecules, including peptides, resulting in lack of efficacy ofthese compounds if applied topically. Considerable research effort has beenfocussed on the development of skin penetration enhancement techniques. However,many of these techniques have been limited by insufficient penetration enhancementand/or induced irritancy.We have investigated three approaches to enhance the delivery of peptides that havetherapeutic or cosmetic effect in the skin. These approaches include the use ofphysical energy to enhance the delivery of Alanine-Tryptophan (Ala-Trp), lipoaminoacid (LAA) conjugation to increase the permeability of a HNE inhibitor Ala-Ala-Pro-Val (AAPV) and a cosmetic peptide, acetyl hexapeptide-3 and cyclisation to enhancethe delivery of a core peptide (CP) which has anti-inflammatory activity.In vitro permeation studies across human epidermis were performed in Pyrex glassFranz-type diffusion cells. Ala-Trp was selected as a small molecular weight modeldipeptide to study the penetration enhancement effects of Dermaportation, which is anewly developed pulsed electro magnetic field (PEMF) technology. The dipeptidewas found to be unstable on exposure to skin at 37°C and Dermaportation (Pulsedelectromagnetic field technology) significantly increased the in vitro permeabilitycoefficient of Ala-Trp across human epidermis from 7.7 x 10-4 cm/h with passivediffusion to 1.94 x 10-2 cm/h with Dermaportation over an 8 h period.Dermaportation thus may provide an effective means of delivering molecules that arehighly susceptible to degradation like dipeptides, in higher amounts and in arelatively short duration.The effectiveness of coupling a short chain lipoamino acid to enhance transepidermaldelivery of a model human neutrophil elastase (HNE) inhibitor (Ala-Ala-Pro-Val) was assessed. The optimal conjugate structure for skin penetration andbiological activity of this therapeutic peptide with anti-inflammatory activity wasdetermined. In order to enhance the trans-epidermal delivery of the peptide,lipophilic derivatives with LAAs of chain length C6, C8, and C10 were prepared bysolid phase synthesis. Conjugation to a C6-LAA enhanced epidermal permeability ofthe tetrapeptide. Stereoselective permeation of the lipopeptide diastereomers acrossthe human epidermis was observed. The amount of C6(D)-LAA-AAPV (467.94μg/cm2) was significantly higher than C6(L)–LAA-AAPV (123.04 μg/cm2). Thesame was observed with C8(D)-LAA-AAPV. The effect of donor concentration andskin hydration on skin permeability of C8(D,L)-LAA-AAPV and C10(D,L)-LAAAAPVwas also assessed and it was observed that there was higher permeation ofC10(D,L)-LAA-AAPV at a higher donor concentration. The lipoamino acid conjugates were more stable than the native tetrapeptide and biological activity was retained after coupling of the tetrapeptide to C6, C8 and C10 LAA.A cosmetic peptide, acetyl hexapeptide-3 was coupled to individual diastereomers ofC12 (A)-LAA and C12 (B)-LAA. The preliminary study was designed to assess theeffect of coupling of a LAA of higher molecular weight on the transepidermalpermeation and accumulation of this hexapeptide. Accumulation of these peptides inthe skin was also quantified. Detectable amounts of C12(A)-LAA-hexapeptide-3 andC12(B)-LAA-hexapeptide-3 were not found in the receptor solution but higherquantities of these conjugates were found to be retained in the skin. The amount ofC12(B)-LAA-hexapeptide-3 (59.92 μg/cm2 ± 10.64) in the epidermis was highestfollowed by C12(A)-LAA-hexapeptide-3 (33.06 μg/cm2 ± 3.70) and acetylhexapeptide-3 (12.64 μg/cm2 ± 1.48).Lastly, skin permeability and in skin stability of an anti-inflammatory peptide (corepeptide: CP) and two analogues that have demonstrated improved biological efficacyand specificity: a cyclic peptide sequence (C1) and its linear sequence counterpart(C1-L) were assessed. The stability of C1 and C1-L was significantly higher ascompared to CP when placed in contact with skin at 37ºC. The epidermal penetrationof the core anti-inflammatory peptide improved after cyclisation. The order of Lastly, skin permeability and in skin stability of an anti-inflammatory peptide (corepeptide: CP) and two analogues that have demonstrated improved biological efficacyand specificity: a cyclic peptide sequence (C1) and its linear sequence counterpart(C1-L) were assessed. The stability of C1 and C1-L was significantly higher ascompared to CP when placed in contact with skin at 37ºC. The epidermal penetrationof the core anti-inflammatory peptide improved after cyclisation. The order of permeation of the analogues was C1>C1-L>CP after 48h and 6 days. The amount of peptide retained in the skin was higher after 48h as compared to 8h due to greater partitioning of these peptides in the skin.This work demonstrates the enhancement effects of these three techniques tooptimize the transdermal/topical permeation of therapeutic and cosmetic peptides
Universality in Complex Networks: Random Matrix Analysis
We apply random matrix theory to complex networks. We show that nearest
neighbor spacing distribution of the eigenvalues of the adjacency matrices of
various model networks, namely scale-free, small-world and random networks
follow universal Gaussian orthogonal ensemble statistics of random matrix
theory. Secondly we show an analogy between the onset of small-world behavior,
quantified by the structural properties of networks, and the transition from
Poisson to Gaussian orthogonal ensemble statistics, quantified by Brody
parameter characterizing a spectral property. We also present our analysis for
a protein-protein interaction network in budding yeast.Comment: 4+ pages, 4 figures, to appear in PRE, major change in the paper
including titl
Role of delay in the mechanism of cluster formation
We study the role of delay in phase synchronization and phenomena responsible
for cluster formation in delayed coupled maps on various networks. Using
numerical simulations, we demonstrate that the presence of delay may change the
mechanism of unit to unit interaction. At weak coupling values, same parity
delays are associated with the same phenomenon of cluster formation and exhibit
similar dynamical evolution. Intermediate coupling values yield rich
delay-induced driven cluster patterns. A Lyapunov function analysis sheds light
on the robustness of the driven clusters observed for delayed bipartite
networks. Our results reveal that delay may lead to a completely different
relation, between dynamical and structural clusters, than observed for the
undelayed case.Comment: 4+ pages, 4 figues, PRE Rapid Communication (in press
Comparative Analysis of Tamil and English News Text Summarization Using Text Rank Algorithm
The exponential growth of newsgroups has made it more difficult to gain accurate access to a large amount of data. To deal with the massive amounts of data, efficient and effective methods are needed. One such method is text summarization, which presents data in a condensed format. It would be beneficial for readers to be able to get a wide variety of news in a short amount of time if the news is simplified.In this article, we use the English Newsgroup datasets and the Tamil Newsgroup datasets to automate News Summaries using the text rank algorithm. The proposed work was created using a changed Text Rank algorithm based on the principle of word frequency. The suggested approach creates vectors of words as nodes and similarities between two words as the edge between them, which is the webbing between them. Term frequency assigns various weights to different terms in a sentence, while standard cosine similarity regards both of them similarly. The vector is rendered sparse and divided into clusters based on the premise that sentences inside a cluster are identical and sentences from various clusters reflect their dissimilarity. The performance assessment of the proposed summarization strategy in two types of Newsgroup datasets demonstrates its usefulness in terms of the accuracy parameter
Deformed Gaussian Orthogonal Ensemble description of Small-World networks
The study of spectral behavior of networks has gained enthusiasm over the
last few years. In particular, Random Matrix Theory (RMT) concepts have proven
to be useful. In discussing transition from regular behavior to fully chaotic
behavior it has been found that an extrapolation formula of the Brody type can
be used. In the present paper we analyze the regular to chaotic behavior of
Small World (SW) networks using an extension of the Gaussian Orthogonal
Ensemble. This RMT ensemble, coined the Deformed Gaussian Orthogonal Ensemble
(DGOE), supplies a natural foundation of the Brody formula. SW networks follow
GOE statistics till certain range of eigenvalues correlations depending upon
the strength of random connections. We show that for these regimes of SW
networks where spectral correlations do not follow GOE beyond certain range,
DGOE statistics models the correlations very well. The analysis performed in
this paper proves the utility of the DGOE in network physics, as much as it has
been useful in other physical systems.Comment: Replaced with the revised version, accepted for publication in Phys.
Rev.
Considering Two Sides of One Review Using Stanford NLP Framework
Sentiment analysis is a type of natural language processing for tracking the mood of the public about a particular product or a topic and is useful in several ways. Polarity shift is the most classical task which aims at classifying the reviews either positive or negative. But in many cases, in addition to the positive and negative reviews, there still many neutral reviews exist. However, the performance sometimes limited due to the fundamental deficiencies in handling the polarity shift problem. We propose an Improvised Dual Sentiment Analysis (IDSA) model to address this problem for sentiment classification. We first propose a novel data expansion technique by creating sentiment-reversed review for each training and test review. We develop a corpus based method to construct a pseudo-antonym dictionary. It removes DSA’s dependency on an external antonym dictionary for review reversion. We conduct a range of experiments and the results demonstrates the effectiveness of DSA in addressing the polarity shift in sentiment classification.
Human otoacariasis: a common outbreak in rubber growing belt of Karnataka.
Background/Objective: Soft tick in the ear is a very common acute painful and distressing condition in the flowering months of October to March. It’s a common condition in the rubber growing belt of Sullia.The mouthparts of the tick grips firmly the skin of the external auditory canal or the tympanic membrane and sucks blood and swells up. Otoscopy and removal of the tick from the ear can be done in outpatients in adults and difficult in a frightened irritable child.Materials and methods: 312 cases of intra-aural ticks presenting to the opd and casualty which included 131 males and 181 females were included in the study.Results: Out of the 312 cases of intra-aural ticks, 170 cases were treated in the outpatient and 140 cases under short general anesthesia with oto-microscopy.Conclusion: Intra-aural tick infestation is an acute painful condition which needs prompt management by an experienced otolaryngologist. Proper visualization and instrumentation is necessary to avoid complications.
Crouzon’s syndrome with adenotonsillitis: conventional surgery in altered anatomy.
Background/Objectives: Crouzon’s syndrome is characterized by premature closure of the cranial sutures, midface hypoplasia, orbital deformities & other associated abnormalities.Children with Crouzon syndrome frequently have obstructive sleep apnea due to the underdevelopment of the midface.Case report: A 12 year old boy of Crouzon’s syndrome with chronic adeno-tonsillitis was managed by adeno-tonsillectomy under general anaesthesia by scalpel cautery method. The boyresponded well to surgery & the mild sleep disorder disappeared within a week uveventfully.Conclusion: Sleep disorders in this condition can be treated by improving the airway by selective procedures like midface advancement, mandibular expansion , adeno-tonsillectomy,uvulo-palatopharyngoplasty, anterior tongue reduction & endoscopic tracheal granuloma excision.
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