Acharya Narendra Dev College

Delhi, India

Acharya Narendra Dev College

Delhi, India
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Ahmad I.,Maulana Azad Medical College and Associated hospitals | Mir R.,Maulana Azad Medical College and Associated hospitals | Zuberi M.,Maulana Azad Medical College and Associated hospitals | Javid J.,Maulana Azad Medical College and Associated hospitals | And 13 more authors.
Journal of Cancer Science and Therapy | Year: 2013

Background: The epigenetic impact of DNA methylation in chronic myelogenous leukemia (CML) is not completely understood. RIZ1 expression and activity are reduced in many cancers. In CML, blastic transformation is associated with loss of heterozygosity in the region where RIZ1 is located. RIZ1 is a PR domain methyltransferase that methylates histone H3 lysine 9, a modification important for transcriptional repression. In CML blast crisis cell lines RIZ1 represses insulin-like growth factor-1 expression and autocrine signaling. Together these observations suggest that RIZ1 may have a role in the chronic phase to blast crisis transition in CML. Methods: To examine whether promoter methylation is involved in the disease development and progression of CML, we investigated promoter methylation status of RIZ1 gene in 100 chronic myeloid leukemia's (CML) patients and 50 controls by MSP method. Results: The RIZ1 methylation was studied in 100 CML patients, 9 were cases were methylation positive cases, six of nine were in blastic phase, 2 in chronic phase and one patient in accelerated phase. It was seen that RIZ1 methylation was increased significantly from early to advanced phase. The higher frequency of RIZ1 methylation was reported in haematologically resistant cases (42% vs 2%) and molecularly resistant cases (16.77% vs 1.92%) than the responders. The higher frequency of RIZ1 methylation was found in CML patients who were treated with interferon initially followed by imatinib treatment. Also RIZ1 hypermethylation was associated with faster disease progression p<0.003 than the non methylated cases. No correlation was found between RIZ1 gene methylation with age, thrombocytopenia, types of bcr/abl transcripts of CML patients. Conclusion: We conclude that epigenetic silencing of RIZ1 gene is associated with CML progression and imatinib resistance. Early detection of RIZ1 methylation could be a predictive marker for imatinib resistance and disease progression in CML. © 2013 Imtiyaz Ahmad AB, et al.


Tyagi P.,Acharya Narendra Dev College | Mishra R.K.,University of Delhi | Mehra N.C.,University of Delhi | Vedeshwar A.G.,University of Delhi
Integrated Ferroelectrics | Year: 2010

Group IIB iodides are layered structured semiconductors and are chosen particularly for studying the residual stress dependence of band gap because of their anisotropy along and across the layers. The development of residual stress with film thickness, substrate temperature, annealing temperature etc. was studied using X-ray diffraction in these films grown by vacuum evaporation. The three compounds show completely different growth and residual stress behaviors. The room temperature optical band gaps of these films were determined by optical absorption measurements. Only ZnI2 exhibits excitonic absorption at room temperature. The optical band gaps of ZnI2 and HgI2 correlate linearly with residual stress while CdI2 shows nonlinear behavior. The magnitude of band gap variation with residual stress can be interpreted as due to the affected cation-cation, cation-anion and anion-anion bond lengths. The ionicity of these three compounds decreases linearly with their cation-anion radii ratio and the band gap increases with ionicity. Copyright © 2010 Taylor & Francis Group, LLC.


Khandelwal D.,Indian Institute of Technology Delhi | Hooda S.,Acharya Narendra Dev College | Brar A.S.,Indian Institute of Technology Delhi | Brar A.S.,Guru Nanak Dev University | Shankar R.,Indian Institute of Technology Delhi
Journal of Polymer Research | Year: 2014

An investigation of the microstructure of isobornyl methacrylate - styrene (I/S) copolymers prepared by the atom transfer radical polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA copper complex as catalyst under nitrogen atmosphere at 70 °C has been done by two-dimensional NMR techniques. 2D-HSQC and TOCSY have been utilized to resolve the complex 1H NMR spectrum and to establish the compositional and configurational sequences of isobornyl methacrylate-styrene (I/S) copolymers. 2D HSQC and TOCSY spectra showed compositional and configurational sensitivity of α-methyl carbon of I unit and methine proton of S unit and are assigned up to the triad level. The methylene carbon (C10) also shows triad level of compositional sensitivity in 2D HSQC spectra. Heteronuclear multiple-bond correlation (HMBC) spectroscopy has been used to study carbonyl/quaternary carbon-proton coupling. The carbonyl and quaternary carbons showed compositional and configurational sensitivity upto the triad level. The values of reactivity ratios were determined by Kelen-Tudos (KT) and nonlinear error in variable method (RREVM) using copolymer composition data that were determined by 1H NMR spectrum. Reactivity ratios of comonomers in I/S copolymer, determined from a linear Kelen-Tudos method (KT) and non-linear Error-in-Variable Method (EVM), are rI=0.39±0.09, r S=0.44±0.08 and rI= 0.42, rS=0.47, respectively. © Springer Science+Business Media Dordrecht 2014.


Khandelwal D.,Indian Institute of Technology Delhi | Hooda S.,Acharya Narendra Dev College | Brar A.S.,Guru Nanak Dev University | Shankar R.,Indian Institute of Technology Delhi
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2012

Copolymerization of isobornyl methacrylate and methyl acrylate (I/M) is performed by atom transfer radical polymerization using methyl-2-bromopropionate as an initiator and PMDETA/CuBr as catalyst under nitrogen atmosphere at 70 °C. The copolymer compositions determined from 1H NMR spectra are used to determine reactivity ratios of the monomers. The reactivity ratio determined from linear Kelen-Tudos method and non-linear error-in-variable method, are r I = 1.25 ± 0.10, r M = 0.84 ± 0.08 and r I = 1.20, r M = 0.82, respectively. 1D, distortion less enhancement by polarization transfer and 2D, heteronuclear single quantum coherence, and total correlation spectroscopy NMR experiments are employed to resolve highly overlapped and complex 1H and 13C{ 1H} NMR spectra of the copolymers. The carbonyl carbon of I and M units and methyl carbon of I unit are assigned up to triad compositional and configurational sequences, whereas β-methylene carbons are assigned up to tetrad compositional and configurational sequences. Similarly, methine carbon of I unit is assigned up to triad level. The couplings of carbonyl carbon and quaternary carbon resonances are studied in detail using 2D hetero nuclear multiple bond correlation spectra. © 2012 Wiley Periodicals, Inc.


Khandelwal D.,Indian Institute of Technology Delhi | Hooda S.,Acharya Narendra Dev College | Brar A.S.,Guru Nanak Dev University | Shankar R.,Indian Institute of Technology Delhi
Journal of Applied Polymer Science | Year: 2012

Isobornyl acrylate (B)/methacrylonitrile (N) copolymers with different compositions were synthesized by the free-radical bulk polymerization with azobisisobutyronitrile as the initiator under a nitrogen atmosphere at 70°C. The copolymer compositions were calculated from quantitative 13C( 1H)NMR spectra. The reactivity ratios of the comonomers in the B/N copolymers determined from the linear Kelen-Tudos method and nonlinear error-in-variable method were r B = 0.66 ± 0.11 and r N = 1.54 ± 0.22 and r B = 0.74 and r N = 1.65, respectively. The complete spectral assignments of the 1H-NMR and 13C( 1H)-NMR spectra were carried out with the help of distortionless enhancement by polarization transfer, two-dimensional (2D) heteronuclear single quantum coherence, and 2D total correlation spectroscopy. The nitrile carbon of the N unit and the methine and OCH carbons of the B unit were assigned to triad compositional sequences, whereas the β-methylene carbons of the B and N units were assigned to the tetrad compositional and configurational sequences. The α-methyl carbon of the N unit was also assigned to the triad level of configurational and compositional sequences. Similarly, the nitrile and quaternary carbon resonances with the methine, methylene, and methyl protons were studied in detail with 2D heteronuclear multiple-bond correlation spectra. © 2012 Wiley Periodicals, Inc.


Khandelwal D.,Indian Institute of Technology Delhi | Hooda S.,Acharya Narendra Dev College | Brar A.S.,Guru Nanak Dev University
Journal of Molecular Structure | Year: 2011

Poly(isobornyl acrylate) (PiBA) was prepared by atom transfer radical polymerization (ATRP). Complete characterization of microstructure of PiBA was carried out using one-dimensional [1H, 13C{1H}] and two-dimensional (HSQC, TOCSY and HMBC) NMR spectra. The methyl, methylene, methine, quaternary and carbonyl carbon resonance signals were found to be sensitive to various configurational sequences. The methine carbon (C 12) was assigned up to triad configurational sequences in 13C{1H} NMR spectrum whereas β-methylene carbon resonances were assigned up to diad configurational sequences. The quaternary carbon in 13C{1H} NMR spectrum were resolved completely with the help of HMBC NMR spectrum. The stereoregularity of PiBA was found to be random with mm = 20%, mr = 53%, and rr = 27%. © 2011 Elsevier B.V. All rights reserved.


Khandelwal D.,Indian Institute of Technology Delhi | Hooda S.,Acharya Narendra Dev College | Brar A.S.,Guru Nanak Dev University | Shankar R.,Indian Institute of Technology Delhi
Journal of Molecular Structure | Year: 2011

Isobornyl acrylate - methyl methacrylate (B/M) copolymers of different compositions were synthesized by atom transfer radical polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA copper complex as catalyst under nitrogen atmosphere at 70 °C. 1H NMR spectrum was used to determine the compositions of copolymer. The copolymer compositions were then used to determine the reactivity ratios of monomers. Reactivity ratios of co-monomers in B/M copolymer, determined from linear Kelen-Tudos method (KT) and non linear Error-in-Variable Method (EVM), are r B = 0.41 ± 0.11, r M = 1.11 ± 0.33 and r B = 0.52, r M = 1.31 respectively. The complete resonance assignments of 1H and 13C{ 1H} NMR spectra were carried out with the help of Distortion less Enhancement by Polarization Transfer (DEPT), two-dimensional Heteronuclear Single Quantum Coherence (HSQC). 2D HSQC assignments were further confirmed by 2D Total Correlation Spectroscopy (TOCSY). The carbonyl carbon of B and M units and methyl carbon of M unit were assigned up to triad compositional and configurational sequences whereas β-methylene carbons were assigned up to tetrad compositional and configurational sequences. Similarly the methine carbon of B unit was assigned up to pentad level. 1,3 and 1,4 bond order couplings of carbonyl carbon and quaternary carbon resonances with methine, methylene and methyl protons were studied in detail using 2D Hetero Nuclear Multiple Bond Correlation (HMBC) spectra. © 2011 Elsevier B.V. All rights reserved.


Khandelwal D.,Indian Institute of Technology Delhi | Hooda S.,Acharya Narendra Dev College | Brar A.S.,Guru Nanak Dev University | Shankar R.,Indian Institute of Technology Delhi
Journal of Molecular Structure | Year: 2013

Isobornyl acrylate/styrene (B/S) copolymers of different compositions have been prepared by Atom Transfer Radical Polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA/ CuBr as catalyst under nitrogen atmosphere at 60 °C. Copolymer compositions calculated from 1H NMR spectra are used to determine the reactivity ratios of monomers. Linear Kelen-Tudos (KT) and non-linear error in variable methods (EVM) have been employed for determination of monomer reactivity ratios in copolymers. The reactivity ratios obtained from KT and EVM are found to be rB = 0.41 ± 0.08, rS = 0.92 ± 0.13 and rB = 0.41 and rS = 0.93 respectively. These copolymers have been analyzed for their stereochemical structure using various 1D ( 1H, 13C{1H}, DEPT) and 2D (HSQC, TOCSY, NOESY, HMBC) NMR techniques. 2D HSQC and TOCSY NMR experiments are employed to resolve the highly overlapped and complex 1H and 13C{ 1H} NMR spectra of the copolymers. Spatial coupling of different types of protons are resolved by 2D NOESY NMR spectra. The configurational and compositional sequences of β-methylene carbons are assigned upto tetrad level whereas methine carbon is assigned as triad level of compositional sequences. The quaternary carbon of styrene and carbonyl carbon of isobornyl acrylate have been assigned as triad level of compositional sequences and are further confirmed by 2D HMBC NMR spectra. © 2013 Elsevier Ltd. All rights reserved.

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