arXiv subjects

Dinesh Kumar

Publications and source records attributed to Dinesh Kumar.

At least 109 records · Page 6Linked to original sources

arXiv2016

Escaping set and Julia set of transcendental semigroups

We discuss the dynamics of semigroups of transcendental entire functions using Fatou-Julia theory and provide a condition for the complete invariance of escaping set and Julia set of transcendental semigroups. Results regarding limit functions and postsingular set are also derived. In addition, classes of hyperbolic and postsingularly bounded transcendental semigroups are given. We also provide certain criterion for non existence of wandering domains of transcendental semigroups.

math.DS↗

arXiv2016

NMR based Pharmaco-metabolomics: An efficient and agile tool for therapeutic evaluation of Traditional Herbal Medicines

Traditional Indian (Ayurvedic) and Chinese herbal medicines have been used in the treatment of a variety of diseases for thousands of years because of their natural origin and lesser side effects. However, the safety and efficacy data (including dose and quality parameters) on most of these traditional medicines are far from sufficient to meet the criteria needed to support their world-wide therapeutic use. Also, the mechanistic understanding of most of these herbal medicines is still lacking due to their complex components which further limits their wider application and acceptance. Metabolomics -a novel approach to reveal altered metabolism (biochemical effects) produced in response to a disease or its therapeutic intervention- has huge potential to assess the pharmacology and toxicology of traditional herbal medicines (THMs). Therefore, it is gradually becoming a mutually complementary technique to genomics, transcriptomics and proteomics for therapeutic evaluation of pharmaceutical products (including THMs); the approach is so called pharmaco-metabolomics. The whole paradigm is based on its ability to provide metabolic signatures to confirm the diseased condition and then to use the concentration profiles of these biomarkers to assess the therapeutic response. Nuclear magnetic resonance (NMR) spectroscopy coupled with multivariate data analysis is currently the method of choice for pharmaco-metabolomics studies owing to its unbiased, non-destructive nature and minimal sample preparation requirement. In recent past, dozens of NMR based pharmaco-metabolomic studies have been devoted to prove the therapeutic efficacy/safety and to explore the underlying mechanisms of THMs, with promising results. The current perspective article summarizes various such studies in addition to describing the technical and conceptual aspects involved in NMR based pharmaco-metabolomics.

q-bio.BM↗

arXiv2015

The dynamics of semigroups of transcendental entire functions II

We introduce the concept of escaping set for semigroups of transcendental entire functions using Fatou-Julia theory. Several results of the escaping set associated with the iteration of one transcendental entire function have been extended to transcendental semigroups. We also investigate the properties of escaping sets for conjugate semigroups and abelian transcendental semigroups. Several classes of transcendental semigroups for which Eremenko's conjectures hold have been provided.

math.DS↗

arXiv2015

Dynamics of composite entire functions

It is known that the dynamics of $f$ and $g$ vary to a large extent from that of its composite entire functions. Using Approximation theory of entire functions, we have shown the existence of entire functions $f$ and $g$ having infinite number of domains satisfying various properties and relating it to their composition. We have explored and enlarged all the maximum possible ways of the solution in comparison to the past result worked out.

math.DS↗

arXiv2015

Semigroups of transcendental entire functions and their dynamics

We study the dynamics of an arbitrary semigroup of transcendental entire functions using Fatou-Julia theory. Several results of the dynamics associated with iteration of a transcendental entire function have been extended to transcendental semigroups. We provide some conditions for connectivity of the Julia set of the transcendental semigroups. We also study finitely generated transcendental semigroups, abelian transcendental semigroups and limit functions of transcendental semigroups on its invariant Fatou components.

math.DS↗

arXiv2015

Use of biogenic nanomaterials to improve the peritoneal dialysis technique: A Translational Research Perspective

Intraperitoneal and catheter exit site infections are the most common complications associated with prolonged peritoneal dialysis (PD) therapy used for treating the patients with end stage renal failure (ESRF). Recurrent and persistent infections often cause inflammation of the peritoneum, a condition known as infectious peritonitis and to resolve the condition, patients require antibiotic treatment. However, if the treatment is delayed or if it fails due to antibiotic resistance, the peritonitis may lead to permanent malfunctioning of peritoneal membrane causing technique failure and transferring the patients to haemodialysis. Severe and prolonged peritonitis is not only the major cause of technique failure, it is also the leading cause of mortality and morbidity in PD patients. Therefore, there is an urgent need to improve the existing PD technique so that the frequency of PD associated infections could be reduced and infectious peritonitis episodes thereof during prolonged peritoneal dialysis. In this perspective, I highlight the possibility to improve the PD technique through the use of antimicrobial nanoparticles synthesized biologically.

physics.bio-ph↗

arXiv2015

New-physics signals of a model with a vector-singlet up-type quark

The VuQ model involves the addition of a vector isosinglet up-type quark to the standard model. In this model the full CKM quark mixing matrix is 4 X 3. Using present flavor-physics data, we perform a fit to this full CKM matrix, looking for signals of new physics (NP). We find that the VuQ model is very strongly constrained. There are no hints of NP in the CKM matrix, and any VuQ contributions to loop-level flavor-changing b -> s, b -> d and s -> d transitions are very small. There can be significant enhancements of the branching ratios of the flavor-changing decays t -> u Z and t -> c Z, but these are still below present detection levels.

hep-ph↗

arXiv2014

AADNMR: A Simple Method for Rapid Identification of Bacterial/Mycobacterial Infections in Antibiotic Treated Peritoneal Dialysis Effluent Samples for Diagnosis of Infectious Peritonitis

An efficient method is reported for rapid identification of bacterial or mycobacterial infection in a suspected clinical/biological sample. The method is based on the fact that the ring methylene protons of cyclic fatty acids (constituting the cell membrane of several species of bacteria and mycobacteria) resonate specifically between -0.40 and 0.68 ppm region of the 1H NMR spectrum. These cyclic fatty acids are rarely found in the eukaryotic cell membranes. Therefore, the signals from cyclic ring moiety of these fatty acids can be used as markers (a) for the identification of bacterial and mycobacterial infections and (b) for differential diagnosis of bacterial and fungal infections. However, these microbial fatty acids when present inside the membrane are not easily detectable by NMR owing to their fast T2 relaxation. Nonetheless, the problem can easily be circumvented if these fatty acids become suspended in solution. This has been achieved by abolishing the membrane integrity using broad spectrum antibiotics (including ampicillin). The suspended fatty acids are then detected by NMR to probe the infection. Therefore, the method has been given the name AADNMR i.e. Add Antibiotic to Detect by NMR. The method has been tested here using both Gram positive and Gram negative bacterial strains and finally the utility of method is demonstrated for discriminating bacterial and fungal infections to aid timely diagnosis of infectious peritonitis (a life threatening complication associated with prolonged peritoneal dialysis).

physics.bio-ph↗

arXiv2014

Concrete Attribute-Based Encryption Scheme with Verifiable Outsourced Decryption

As more sensitive data is shared and stored by third-party sites on the internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data is that it can be selectively shared only at a coarse-grained level. Attribute based encryption is a public-key-based one-to-many encryption that allows users to encrypt and decry pt data based on user attributes. A promising application of ABE is flexible access control of encrypted data stored in the cloud using access policies and ascribed attributes associated with private keys and cipher text. One.One of the main efficiency drawbacks of the existing ABE schemes is that decryption involves expensive pairing operations and the number of such operations grows with the complexity of the access policy. Finally, we show an implementation scheme and result of performance measurements, which indicates a significant reduction on computing resources imposed on users.

cs.CR↗

arXiv2014

Pseudo 5D HN(C)N Experiment to Facilitate the Assignment of Backbone Resonances in Proteins Exhibiting High Backbone Shift Degeneracy

Assignment of protein backbone resonances is most routinely carried out using triple resonance three dimensional NMR experiments involving amide 1H and 15N resonances. However for intrinsically unstructured proteins, alpha-helical proteins or proteins containing several disordered fragments, the assignment becomes problematic because of high degree of backbone shift degeneracy. In this backdrop, a novel reduced dimensionality (RD) experiment -(5,3)D-hNCO-CANH- is presented to facilitate (and/or to validate) the sequential backbone resonance assignment in such proteins. The proposed 3D NMR experiment makes use of the modulated amide 15N chemical shifts (resulting from the joint sampling along both its indirect dimensions) to resolve the ambiguity involved in connecting the neighboring amide resonances (i.e. HiNi and Hi-1Ni-1) for overlapping amide NH peaks. The experiment -encoding 5D spectral information- leads to a conventional 3D spectrum with significantly reduced spectral crowding and complexity. The improvisation is based on the fact that the linear combinations of intra-residue and inter-residue backbone chemical shifts along both the co-evolved indirect dimensions span a wider spectral range and produce better peak dispersion than the individual shifts themselves. Taken together, the experiment -in combination with routine triple resonance 3D NMR experiments involving backbone amide (1H and 15N) and carbon (13C-alpha and 13C') chemical shifts- will serve as a powerful complementary tool to achieve the nearly complete assignment of protein backbone resonances in a time efficient manner. The performance of the experiment and application of the method have been demonstrated here using a 15.4 kDa size folded protein and a 12 kDa size unfolded protein.

physics.chem-ph↗

arXiv2014

The dynamics of semigroups of transcendental entire functions I

We consider the dynamics associated with an arbitrary semigroup of transcendental entire functions. Fatou-Julia theory is used to investigate the dynamics of these semigroups. Several results of the dynamics associated with iteration of a transcendental entire function have been extended to transcendental semigroup case. We also investigate the dynamics of conjugate semigroups, Abelian transcendental semigroups and wandering and Baker domains of transcendental semigroups.

math.DS↗

arXiv2014

On dynamics of composite entire functions and singularities

We consider the dynamical properties of transcendental entire functions and their compositions. We give several conditions under which Fatou set of a transcendental entire function $f$ coincide with that of $f\circ g,$ where $g$ is another transcendental entire function. We also prove some result giving relationship between singular values of transcendental entire functions and their compositions.

math.DS↗

arXiv2014

On dynamics of semiconjugated entire functions

Let $g$ and $h$ be transcendental entire functions and let $f$ be a continuous map of the complex plane into itself with $f\circ g=h\circ f.$ Then $g$ and $h$ are said to be semiconjugated by $f$ and $f$ is called a semiconjugacy. We consider the dynamical properties of semiconjugated transcendental entire functions $g$ and $h$ and provide several conditions under which the semiconjugacy $f$ carries Fatou set of one entire function into the Fatou set of other entire function appearing in the semiconjugation. We have also shown that under certain condition on the growth of entire functions appearing in the semiconjugation, the set of asymptotic values of the derivative of composition of the entire functions is bounded.

math.DS↗

arXiv2014

Metabolite Characterization in Peritoneal Dialysis Effluent Using High-resolution 1H and 1H-13C NMR Spectroscopy

Metabolite analysis of peritoneal dialysis (PD) effluent may provide information regarding onset and progression of complications associated with prolonged PD therapy. In this context, the NMR detectable small metabolites of PD effluent samples were characterized using high resolution 1H and 1H-13C NMR spectroscopy. The various spectra were recorded (at 800 MHz proton frequency) on PD effluent samples obtained after 4 hour (intraperitoneal) dwell time from patients with end stage renal failure (ESRF) and continuing normally on PD therapy. Inspite of devastating spectral feature of PD effluent due to the presence of intense resonances from glucose and lactate, we were able to identify about 53 small endogenous metabolites (including many complex coupled spin systems) and more than 90 % of the total CH cross peaks of 1H-13C HSQC spectrum were identified specific to various metabolites of PD effluent. We foresee that the characteristic fingerprints of various metabolites of control PD effluent samples will be used to identify and distinguish metabolic differences from PD related complications.

physics.bio-ph↗

arXiv2013

Reduced Dimensionality tailored HN(C)N Pulse Sequences for Efficient Backbone Resonance Assignment of Proteins through Rapid Identification of Sequential HSQC peaks

Two novel reduced dimensionality (RD) experiments -(4,3)D-hNCOcaNH and (4,3)D-hNcoCANH- have been presented here to facilitate the backbone resonance assignment of proteins both in terms of its accuracy and speed. The experiments basically represent an improvisation of previously reported HN(C)N experiment [Panchal et. al., J. Biomol. NMR. (2002), 20 (2), 135-147] and exploit the simple reduced dimensionality NMR concept [Szyperski et. al. (2002), Proc. Natl. Acad. Sci. U.S.A. 99(12), 8009-8014] to achieve (a) higher dispersion and resolution along the co-evolved F1 dimension and (b) rapid identification of sequential HSQC peaks on its F2(15N)- F3(1H) planes. The current implementation is based on the fact that the linear combination of 15N and 13CO/13Ca chemical shifts offers relatively better dispersion and randomness compared to the individual chemical shifts; thus enables the assignment of crowded HSQC spectra by resolving the ambiguities generally encountered in HNCN based assignment protocol because of amide 15N shift degeneracy. Additionally, each of these experiments enables assignment of backbone 13CO/13Ca resonances as well. Overall, the reduced dimensionality tailored HNCN experiments presented here will be of immense value for various structural and functional proteomics studies by NMR; particularly of intrinsically or partially/unstructured proteins and medium sized (MW ~12-15 kDa) folded proteins. The experiments, like any other experiment that yields protein assignments, would be extremely valuable for protein folding and drug discovery programs as well.

physics.bio-ph↗

arXiv2013

A note on Schwarzian derivatives and normal families

We establish a criterion for local boundedness and hence normality of a family $\F$ of analytic functions on a domain $D$ in the complex plane whose corresponding family of derivatives is locally bounded. Furthermore we investigate the relation between domains of normality of a family $\F$ of meromorphic functions and its corresponding Schwarzian derivative family. We also establish some criterion for the Schwarzian derivative family of a family $\F$ of analytic functions on a domain $D$ in the complex plane to be a normal family.

math.DS↗

arXiv2013

Reduced Dimensionality (4,3)D-hnCOCANH Experiment: An Efficient Backbone Assignment tool for NMR studies of Proteins

Sequence specific resonance assignment and secondary structure determination of proteins form the basis for variety of structural and functional proteomics studies by NMR. In this context, an efficient standalone method for rapid assignment of backbone (1H, 15N, 13Ca and 13C') resonances and secondary structure determination of proteins has been presented here. Compared to currently available strategies used for the purpose, the method employs only a single reduced dimensionality (RD) experiment -(4,3)D-hnCOCANH and exploits the linear combinations of backbone (13Ca and 13C') chemical shifts to achieve a dispersion relatively better compared to those of individual chemical shifts (see the text) for efficient and rapid data analysis. Further, the experiment leads to the spectrum with direct distinction of self (intra-residue) and sequential (inter-residue) carbon correlation peaks; these appear opposite in signs and therefore can easily be discriminated without using an additional complementary experiment. On top of all this, the main strength of the method is its efficient and robust assignment strategy based on: (a) multiple, but unidirectional sequential 15N and 13C correlations (i-->i-1) and (b) the distinctive peak patterns of self and sequential peaks in different [(F1(13C)-F3(1H) and (F2(15N)-F3(1H)] planes of the 3D spectrum which enable ready identification of certain specific triplet sequences (see the text) and thus serve as check points for mapping the stretches of sequentially connected HSQC cross peaks on to the primary sequence for assigning the resonances sequence specifically. Overall, the standalone method presented here will be an important backbone assignment tool for structural and functional proteomics, protein folding, and drug discovery research programs by NMR.

physics.bio-ph↗

arXiv2012

Escaping Set of e^z-1

We investigate the set I(f) of points that converge to infinity under iteration of the map f(z) = e^z-1 and show that it is the disjoint union of countably many rays and uncountable union of infinite sets whose points escape to infinity through the sets.

math.DS↗