harinder singh - Academia.edu (original) (raw)

Papers by harinder singh

Molecules

Essential oils (EOs) are naturally occurring volatile aromatic compounds extracted from different... more Essential oils (EOs) are naturally occurring volatile aromatic compounds extracted from different parts of plants. They are made up of components like terpenes, phenols, etc., and are chemically unstable and susceptible to oxidative deterioration, leading to reduced shelf-life and overall degradation of the product. Encapsulation of EOs in a matrix can prevent degradation of the active ingredient and improve the shelf-life. In this paper, we report encapsulation of Dhavana oil (Artemisia pellen) in a modified starch matrix using a spray-drying technique. Physico-chemical properties of neat and encapsulated Dhavana oil were studied. We selected two powder bases: CaCO3 and TALC and, loaded neat and encapsulated Dhavana oil in it, studied their stability and interaction with the base matrices at 3 °C, 22 °C and 45 °C up to 2 months under closed conditions and one week at 22 °C and 45 °C under open condition. Thermal degradation pattern was studied for neat and encapsulated Dhavana oil ...

Children

Advances in the field have improved the prenatal management of cardiovascular diseases over the p... more Advances in the field have improved the prenatal management of cardiovascular diseases over the past few decades; however, there remains considerable challenges in the approach towards patient selection as well as the applicability of available therapies. This review aims to discuss the current knowledge, outcomes and challenges for prenatal intervention for congenital heart disease.

We have obtained spectra for 1273 stars using the 0.9m Coudé Feed telescope at Kitt Peak National... more We have obtained spectra for 1273 stars using the 0.9m Coudé Feed telescope at Kitt Peak National Observatory. This telescope feeds the coudé spectrograph of the 2.1m telescope. The spectra have been obtained with the #5 camera of the coudé spectrograph and a Loral 3K X 1K CCD. Two gratings have been used to provide spectral coverage from 3460Å to 9464Å, at a resolution of ∼1Å FWHM and at an original dispersion of 0.44Å/pixel. For 885 stars we have complete spectra over the entire 3460Å to 9464Å wavelength region (neglecting – 2 – small gaps of < 50Å), and partial spectral coverage for the remaining stars. The 1273 stars have been selected to provide broad coverage of the atmospheric parameters T ef f , log g, and [Fe/H], as well as spectral type. The goal of the project is to provide a comprehensive library of stellar spectra for use in the automated classification of stellar and galaxy spectra and in galaxy population synthesis. In this paper we discuss the characteristics of t...

Mutations in the cardiac sodium channel gene SCN5A are linked to arrhythmias, cardiac conduction ... more Mutations in the cardiac sodium channel gene SCN5A are linked to arrhythmias, cardiac conduction defects and cardiomyopathies. We report a 2 year old toddler with symptomatic sinus node dysfunction, negative family history, and increased left ventricular trabeculations. He underwent an unsuccessful attempt at transvenous pacemaker implantation, with no pacing capture at multiple ventricular and atrial sites. He required resuscitation for ventricular fibrillation, and was placed on extracorporeal membrane oxygenation (ECMO) support. Genetic analysis revealed compound heterozygous SCN5A loss-of-function and gain-offunction mutations, individually inherited from both his parents. In addition to the full spectrum of manifestations of SCN5A mutations, our patient also exhibited ventricular inexcitability.

A 41-year-old male born with complex congenital heart defects after multiple cardiac surgeries pr... more A 41-year-old male born with complex congenital heart defects after multiple cardiac surgeries presented with symptomatic sinus node dysfunction and atrial flutter. Prior to pacemaker implantation, he was detected to have elevated central venous pressures and dilated scarred quiescent right atrium (RA). Three-dimensional mapping of the RA was carried out during the electrophysiology study and was used to target the site of atrial lead implantation for pacing the RA as there was only a small area of electrically active atrial tissue with adequate sensing and pacing. This simple, innovative technique for lead implantation can be used to target specific sites in certain cases.

Monthly Notices of the Royal Astronomical Society, 2020

High-resolution optical spectra were obtained in 2017–2019 with The Southern African Large Telesc... more High-resolution optical spectra were obtained in 2017–2019 with The Southern African Large Telescope of 15 stars in the direction of the Vela supernova remnant. Interstellar Ca ii H & K and Na i D lines are discussed in this paper. In particular, the line profiles are compared with profiles at a comparable spectral resolution obtained in 1993–1996 by Cha and Sembach. Ten of the lines of sight show changes to one or more of the components in that line of sight. Changes include small changes (1–2 km s−1) in radial velocity and/or increases/decreases in equivalent width over the two decades between the periods of observation. Changes are more obvious in the Ca K line than in the Na D lines. These changes are attributed to gas disturbed by interactions between the supernova ejecta and the surrounding interstellar medium. A representative time-scale may be 20–50 yr. Small-scale variations in line profiles across the face of the remnant suggest, as previously remarked, that a linear scale...

Monthly Notices of the Royal Astronomical Society, 2017

In a survey conducted between 2011 and 2012 of interstellar Na I D line profiles in the direction... more In a survey conducted between 2011 and 2012 of interstellar Na I D line profiles in the direction of the Vela supernova remnant (SNR), a few lines of sight showed dramatic changes in lowvelocity absorption components with respect to profiles from 1993 to 1994 reported by Cha & Sembach. Three stars-HD 63578, HD 68217 and HD 76161-showed large decrease in strength over the 1993-2012 interval. HD 68217 and HD 76161 are associated with the Vela SNR whereas HD 63578 is associated with γ 2 Velorum wind bubble. Here, we present high spectral resolution observations of Ca II K lines obtained with the Southern African Large Telescope towards these three stars along with simultaneous observations of Na I D lines. These new spectra confirm that the Na D interstellar absorption weakened drastically between 1993-1994 and 2011-2012 but show for the first time that the Ca II K line is unchanged between 1993-1994 and 2015. This remarkable contrast between the behaviour of Na D and Ca II K absorption lines is a puzzle concerning gas presumably affected by the outflow from the SNR and the wind from γ 2 Velorum.

Theranostics, 2017

While insulin replacement therapy restores the health and prevents the onset of diabetic complica... more While insulin replacement therapy restores the health and prevents the onset of diabetic complications (DC) for many decades, some T1D patients have elevated hemoglobin A1c values suggesting poor glycemic control, a risk factor of DC. We surveyed the stool microbiome and urinary proteome of a cohort of 220 adolescents and children, half of which had lived with T1D for an average of 7 years and half of which were healthy siblings. Phylogenetic analysis of the 16S rRNA gene did not reveal significant differences in gut microbial alpha-diversity comparing the two cohorts. The urinary proteome of T1D patients revealed increased abundances of several lysosomal proteins that correlated with elevated HbA1c values. In silico protein network analysis linked such proteins to extracellular matrix components and the glycoprotein LRG1. LRG1 is a prominent inflammation and neovascularization biomarker. We hypothesize that these changes implicate aberrant glycation of macromolecules that alter lys...

Indian Pacing and Electrophysiology Journal, 2013

Biology direct, Jan 25, 2016

One of the major challenges in the field of system biology is to understand the interaction betwe... more One of the major challenges in the field of system biology is to understand the interaction between a wide range of proteins and ligands. In the past, methods have been developed for predicting binding sites in a protein for a limited number of ligands. In order to address this problem, we developed a web server named 'LPIcom' to facilitate users in understanding protein-ligand interaction. Analysis, comparison and prediction modules are available in the "LPIcom' server to predict protein-ligand interacting residues for 824 ligands. Each ligand must have at least 30 protein binding sites in PDB. Analysis module of the server can identify residues preferred in interaction and binding motif for a given ligand; for example residues glycine, lysine and arginine are preferred in ATP binding sites. Comparison module of the server allows comparing protein-binding sites of multiple ligands to understand the similarity between ligands based on their binding site. This module...

Context. We show the use of Principal component analysis (PCA) and Fourier decomposition (FD) met... more Context. We show the use of Principal component analysis (PCA) and Fourier decomposition (FD) method as tools for variable star diagnostics. Aims. To compare the relative performance of the two methods (FD & PCA) in revealing the changes in the light curve structures of pulsating Cepheids and in the classification of variable stars. Methods. We have calculated the Fourier parameters from the individual light curves of a variety of variables, e.g., RR Lyraes, Cepheids, Mira Variables and extrinsic variables. We have also applied PCA to this database of light curves. The inputs to the PCA are the 100 values of the magnitudes for each of the 17606 light curves in the database interpolated between phase 0 to 1. Results. We show that in general, the first few principal components (PC's) are enough to reconstruct the original light curves compared to FD method where 2 to 3 times more number of parameters are required to satisfactorily reconstruct the light curves. The computation of required number of Fourier parameters on the average needs 20 times more CPU time than the computation of required number of PC's. Therefore, PCA does have some advantage over the FD method in analysing the variable stars in a larger database. However in some cases, particularly in finding the resonances in Fundamental mode (FU) Cepheids, the PCA results show no distinct advantages over the FD method. We also demonstrate that the PCA technique can be used to classify variables into different variability classes in an automated, unsupervised way, a feature that has immense potential for larger databases of the future.

Artificial neural networks are algorithms which have been developed to tackle a range of computat... more Artificial neural networks are algorithms which have been developed to tackle a range of computational problems. These range from modelling brain function to making predictions of time-dependent phenomena to solving hard (NP-complete) problems. In this introduction we describe a single, yet very important, type of network known as a feedforward network. This network is a mathematical model which can be trained to learn an arbitrarily complex relationship between a data and a parameter domain, so can be used to solve interpolation and classification problems. We discuss the structure, training and interpretation of these networks, and their implementation, taking the classification of stellar spectra as an example.

The Journal of Thoracic and Cardiovascular Surgery, 2014

The study objective was to determine whether the extracardiac conduit Fontan confers an arrhythmi... more The study objective was to determine whether the extracardiac conduit Fontan confers an arrhythmia advantage over the intracardiac lateral tunnel Fontan. Methods: This multicenter study of 1271 patients compared bradyarrhythmia (defined as need for pacing) and tachyarrhythmia (defined as needing antiarrhythmic therapy) between 602 patients undergoing the intracardiac Fontan and 669 patients undergoing the extracardiac Fontan. The median age at the time of the Fontan procedure was 2.1 years (interquartile range, 1.6-3.2 years) for the intracardiac group and 3.0 years (interquartile range, 2.4-3.9) for the extracardiac group (P<.0001). The median follow-up was 9.2 years (interquartile range, 5-12.8) for the intracardiac group and 4.7 years (interquartile range, 2.8-7.7) for the extracardiac group (P<.0001). Results: Early postoperative (<30 days) bradyarrhythmia occurred in 24 patients (4%) in the intracardiac group and 73 patients (11%) in the extracardiac group (P <.0001). Early postoperative (<30 days) tachyarrhythmia occurred in 32 patients (5%) in the intracardiac group and 53 patients (8%) in the extracardiac group (P ¼ not significant). Late (>30 days) bradyarrhythmia occurred in 105 patients (18%) in the intracardiac group and 63 patients (9%) in the extracardiac group (P <.0001). Late (>30 days) tachyarrhythmia occurred in 58 patients (10%) in the intracardiac group and 23 patients (3%) in the extracardiac group (P<.0001). By multivariate analysis factoring time since surgery, more patients in the extracardiac group had early bradycardia (odds ratio, 2.9; 95% confidence interval, 1.8-4.6), with no difference in early tachycardia, late bradycardia, or late tachycardia. Conclusions: Overall arrhythmia burden is similar between the 2 groups, but the extracardiac Fontan group had a higher incidence of early bradyarrhythmias. There was no difference in the incidence of late tachyarrhythmias over time between the 2 operations. Therefore, the type of Fontan performed should be based on factors other than an anticipated reduction in arrhythmia burden from the extracardiac conduit.

New Astronomy, 2009

We employ an Artificial Neural Network (ANN) based technique to develop a pipeline for automated ... more We employ an Artificial Neural Network (ANN) based technique to develop a pipeline for automated segregation of stars from the galaxies to be observed by Tel-Aviv University UltraViolet Experiment (TAUVEX). We use synthetic spectra of stars from UVBLUE library and selected International Ultraviolet Explorer (IUE) low resolution spectra for galaxies in the ultraviolet (UV) region from 1250 to 3220Å as the training set and IUE low-resolution spectra for both the stars and the galaxies as the test set. All the data sets have been pre-processed to get band integrated fluxes so as to mimic the observations of the TAUVEX UV imager. We also perform the ANN based segregation scheme using the full length spectral features (which will also be useful for the ASTROSAT mission). Our results suggest that, in the case of the non-availability of full spectral features, the limited band integrated features can be used to segregate the two classes of objects; although the band data classification is less accurate than the full spectral data classification.

Monthly Notices of the Royal Astronomical Society, 1998

A fast and robust method of classifying a library of optical stellar spectra for O to M type star... more A fast and robust method of classifying a library of optical stellar spectra for O to M type stars is presented. The method employs, as tools: (1) principal component analysis (PCA) for reducing the dimensionality of the data and (2) multilayer back propagation network (MBPN) based artificial neural network (ANN) scheme to automate the process of classification. We are able to reduce the dimensionality of the original spectral data to very few components by using PCA and are able to successfully reconstruct the original spectra. A number of NN architectures are used to classify the library of test spectra. Performance of ANN with this reduced dimension shows that the library can be classified to accuracies similar to those achieved by Gulati et al. but with less computational load. Furthermore, the data compression is so efficient that the NN scheme successfully classifies to the desired accuracy for a wide range of architectures. The procedure will greatly improve our capabilities in handling and analysing large spectral data bases of the future.

Molecular Cell, 2002

Howard Hughes Medical Institute and IRF-8 can substitute for PU.1 and IRF-4, respec-University of... more Howard Hughes Medical Institute and IRF-8 can substitute for PU.1 and IRF-4, respec-University of Chicago tively, in the assembly of these Ets-IRF ternary com-5841 South Maryland Avenue, MC1028 plexes. Thus, the four possible complexes represent a Chicago, Illinois 60637 unique example of cell-type-specific combinatorial gene regulation that is established by structural diversification within related members of two families of transcrip-Summary tion factors. The interaction of PU.1 and IRF-4 has been exten-The Ets and IRF transcription factor families contain sively analyzed biochemically. It is template directed structurally divergent members, PU.1, Spi-B and IRF-4 and involves two distinct protein-protein interaction sur-(Pip), IRF-8 (ICSBP), respectively, which have evolved faces: (i) the Ets and IRF DNA binding domains and (ii) to cooperatively assemble on composite DNA elethe phosphorylated PEST region of PU.1 and an autoinments and regulate gene expression in the immune hibitory domain in IRF-4 (Brass et al., 1996, 1999). system. Whereas PU.1 recruits IRF-4 or IRF-8 to DNA, Whereas PU.1 binds independently to its recognition it exhibits an anticooperative interaction with IRF-1 site in composite DNA elements with high affinity, IRF-4 and IRF-2. We report here the structure of the ternary interacts weakly with template DNA in the absence of complex formed with the DNA binding domains of PU.1 PU.1. The reduced affinity of IRF-4 for its binding site and IRF-4 on a composite DNA element. The DNA in is attributable to both an intrinsic property of its structurthe complex contorts into an unusual S shape that ally diverged IRF domain as well as the presence of a juxtaposes PU.1 and IRF-4 for selective electrostatic C-terminal autoinhibitory domain. It has been proposed and hydrophobic interactions across the central minor that recruitment of IRF-4 to composite regulatory elegroove. Together, the protein-protein and proteinments by DNA-bound PU.1 involves cooperative inter-DNA interactions provide insights into the stereoaction between the Ets and IRF DNA binding domain chemical basis of cooperativity and anti-cooperativity (DBDs) as well as relief of autoinhibition, which is medibetween Ets and IRF factors. ated by the interaction of the phosphorylated PEST region in PU.1 with the C-terminal regulatory domain of

Journal of the American College of Cardiology, 2001

We sought to evaluate the prognostic value of cardiac troponin I (cTnI) in asymptomatic, ambulato... more We sought to evaluate the prognostic value of cardiac troponin I (cTnI) in asymptomatic, ambulatory patients with chronic renal failure treated with long-term hemodialysis. BACKGROUND Smaller, short-term follow-up studies on this subject have given conflicting results. METHODS A total of 126 ambulatory patients with chronic renal failure treated with long-term hemodialysis were followed for two years for all-cause mortality, cardiac mortality, all-cause hospital admissions and cardiac hospital admissions. Serum cTnI was measured before dialysis at the time of study entry. RESULTS One hundred two patients had normal serum levels of cTnI (Յ0.03 ng/ml) and 24 patients had elevated levels (0.015 Ϯ 0.007 vs. 0.053 Ϯ 0.029 ng/ml, p Ͻ 0.0001). No significant difference in all-cause mortality (20 vs. 4 deaths), cardiac mortality (4 vs. 1 death), all-cause hospital admissions (1.74 Ϯ 1.72 vs. 1.25 Ϯ 1.19 admissions/patient) or cardiac admissions (0.52 Ϯ 0.89 vs. 0.33 Ϯ 0.76 admissions/patient) was present between the patients with normal cTnI levels and those with elevated cTnI levels. Serum cTnI was not significantly different between patients who died versus those who survived (0.022 Ϯ 0.019 vs. 0.022 Ϯ 0.021 ng/ml). Serum cTnI was not an independent predictor of all-cause mortality, cardiac mortality, all-cause admissions or cardiac admissions. Age (older) and serum albumin (lower) were independent predictors of all-cause mortality, whereas a history of myocardial infarction was an independent predictor of cardiac mortality. Serum sodium (lower) was an independent predictor of all-cause hospital admissions, whereas hypertension and previous myocardial infarction were independent predictors of cardiac admissions. The best predictors of the time to death were age (older) and serum sodium level (lower), irrespective of the serum cTnI levels. CONCLUSIONS Cardiac troponin I has a limited role in predicting mortality and hospital admissions in asymptomatic patients with chronic renal failure treated with long-term hemodialysis.

Journal of Cardiac Failure, 2011

Background: Cardiac resynchronization therapy (CRT) has demonstrated improved left ventricular ej... more Background: Cardiac resynchronization therapy (CRT) has demonstrated improved left ventricular ejection fraction (EF), symptoms and outcomes in patients with chronic heart failure (HF). However, little is known about patients that incur early adverse outcomes post-implantation of CRT devices. The goal of this study is to The 15 th Annual Scientific Meeting HFSA S51

Japanese Heart Journal, 1990

Although arrhythmogenic right ventricular dysplasia (ARVD) is believed to involve primarily the r... more Although arrhythmogenic right ventricular dysplasia (ARVD) is believed to involve primarily the right ventricle, left ventricular abnormalities have also been described. We report a case of ARVD with abnormalities of the sinus node, right atrium and atrioventricular node. The biopsies taken from the right atrium and the right ventricle showed replacement of myocardium by fibrous tissue. The pathologic changes of this disease process may extend into the atrium and atrioventricular node.