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Madhu C.,Panjab University | Kaur I.,Central Scientific Instruments Organization CSIO | Kaur N.,Panjab University
Journal of Materials Science: Materials in Electronics | Year: 2017

Wet chemical precipitation route is developed for the synthesis of ZnO nanoparticles using a dipodal receptor as capping agent to control the size and shape of ZnO nanoparticles and also to passivate the surface defects. The capping of ZnO nanoparticles with dipodal receptor is characterized with NMR and IR spectroscopy. EDX analyses also confirmed the presence of organic receptors together with ZnO nanoparticles. The morphology and size of surface modified ZnO nanoparticles is checked by SEM, TEM and DLS spectroscopic techniques. The surface decorated ZnO nanoparticles demonstrate emission peak at 333 nm. The emission peak at 333 nm in case of surface capped ZnO demonstrate fewer surface defects present in comparison to their bulk counterpart, where blue, red, green, yellowish green emission peaks are present. The photophysical studies of ZnO nanoparticles are further carried in presence of metal ions where it is observed that the binding with Mn(II) result in increase in fluorescence intensity. The three fold increase in fluorescence intensity of ZnO nanoparticles in presence of Mn(II) can be utilized in case of lighting devices, where high quantum yield is desirable. To the best of our knowledge, this manuscript represents the first surface decorated ZnO nanoparticles for their application in lighting devices. © 2017 Springer Science+Business Media New York

Renuka,Lovely Professional University | Singh S.K.,Lovely Professional University | Gulati M.,Lovely Professional University | Kaur I.,Central Scientific Instruments Organization CSIO
Powder Technology | Year: 2014

In the present study various crystalline forms of glipizide were prepared in order to enhance dissolution rate of glipizide and to evaluate the stability of developed forms. Four different strategies have been followed to prepare crystalline forms of glipizide - a. crystallization from the methanolic solution of the drug under pH control b. crystallization by vapor diffusion c. crystallization by antisolvent precipitation technique and, d. quench cooling. It could be deciphered from the study of DSC, SEM, PXRD and Raman spectroscopic analysis that six different crystal forms of glipizide (form I, form II, form III, form IV, form V and form VI) were prepared. Among all crystalline forms, the fastest T50% drug release was observed with form III and form V (i.e. within 10min). However, T50% drug release was not observed in case of pure glipizide even till 90min Among all the crystal forms prepared, it was concluded that form V (JMD-7) prepared by diffusing vapors of chloroform in the saturated solution of glipizide in methanol could be considered the best due to its rapid dissolution rate (T50% is 10min), considerably higher extent of dissolution (Q90 is 87.22%) and better stability (F2 value 65.39 between dissolution profiles of fresh and aged form V). Further, the dissolution profile (F2=75), PXRD pattern and DSC thermograms of form V of glipizide converted in capsule dosage form were found similar as that of glipizide powder (form V). This justifies that the manufacturing process will not change the dissolution rate or chemical properties of the difference forms of API. © 2014 Elsevier B.V.

Veer K.,Thapar University | Agarwal R.,Thapar University | Kumar A.,Central Scientific Instruments Organization CSIO
Robotica | Year: 2016

The study of arm muscles for independent operations leading to prosthetic design was carried out. Feature extraction was done on the recorded signal for investigating the voluntary muscular contraction relationship for different arm motions and then repeated factorial analysis of variance (ANOVA) technique was implemented to analyze effectiveness of signal. The electronic design consisted of analog and digital signal processing and controlling circuit and mechanical assembly consisted of wrist, palm and the fingers to grip the object in addition to a screw arrangement connected to a low power DC motor and gear assembly to open or close the hand. The wrist is mechanically rotated to orient the hand in a direction suitable to pick up/hold the object. The entire set up is placed in a casing which provides a cosmetic appeal to the artificial hand and the connected arm. The design criteria include electronic control, reliability, light weight, variable grip force with ease of attachment for simple operations like opening, grasping and lifting objects of different weight with grip force slightly more than enough just like that of a natural hand. Copyright © Cambridge University Press 2014.

Randhawa D.K.K.,Guru Nanak Dev University | Singh M.L.,Guru Nanak Dev University | Kaur I.,Central Scientific Instruments Organization CSIO | Bharadwaj L.M.,Central Scientific Instruments Organization CSIO
2011 IEEE Regional Symposium on Micro and Nanoelectronics, RSM 2011 - Programme and Abstracts | Year: 2011

Molecules are essentially potential candidates for replacing silicon in the nanoelectronic circuits. As the size of devices is being scaled down single electron effects become prominent and will be the governing technology in the futuristic integrated circuits. DNA the life sustaining molecule is a promising candidate for molecular electronics. In this paper the DNA base Cytosine is studied for its electronic properties. The current-voltage characteristics are obtained for the molecule. The characteristics display excellent ON/OFF switching pattern that can be tuned using gate bias. The Cytosine molecule can be used to design molecular logic gates and memories. © 2011 IEEE.

Randhawa D.K.K.,Guru Nanak Dev University | Singh M.L.,Guru Nanak Dev University | Kaur I.,Central Scientific Instruments Organization CSIO | Bharadwaj L.M.,Central Scientific Instruments Organization CSIO
Communications in Computer and Information Science | Year: 2011

Single Electron Transistor is the most prominent nanoelectronic device that will dominate the operations of nanoscaled integrated circuits. Molecules, especially DNA is prophesized to be integral part of the futuristic ICs. In this paper the current voltage characteristics of DNA base Cytosine are obtained by non-equilibrium Green's function combined with density functional theory. The pattern of current flow for an applied voltage sweep of 0-5 V is plotted. The phenomenon of tunneling is exhibited in the characteristics of molecules. The DNA base cytosine displays a typical surge of current in the voltage sweep section of 0.4V-0.6V, indicating single electron effects. The effect of gate voltage on the current-voltage characteristics of cytosine was studied in the gated two-probe setup. The typical section of characteristics of cytosine was re-drawn by varying the gate potential. The application of gate bias exhibits excellent ON/OFF switching for combinations of the two applied voltages- source voltage and gate voltage. Repetitive peaks are also observed in current when gate voltage is varied, fixing source potential. In this paper the cytosine molecule is proposed as a switch, AND gate and OR gate in this paper that can be used in DNA based molecular electronic devices. © 2011 Springer-Verlag.

Narula C.,Panjab University | Kaur I.,Central Scientific Instruments Organization CSIO | Kaur N.,Panjab University
Journal of Materials Science: Materials in Electronics | Year: 2015

Developing the heavy metal free QD-LEDs is required to curtail the risks to human beings and environment. Nanoparticles that are ecofriendly, chemically stable, easy to synthesize, nontoxic, biocompatible too are the preferred one. ZnO are biocompatible and low cost semiconductor nanoparticles with tunable band gap and large excitonic binding energy, which make them suitable for LED applications. To achieve the same purpose, this research work is focused on the synthesis of surface modified ZnO nanoparticles for their application in light emitting diodes. The condensation reaction is used to synthesize the ligand and wet chemical precipitation method is used to synthesize surface modified ZnO nanoparticles. The optical properties are evaluated using UV–Vis absorption and fluorescence studies. The optical properties are also investigated in the presence of metal ions and an increased band gap is achieved when Fe3+ ion is added to organic receptor coated ZnO nanoparticles. The stability of ZnO coupled receptor is confirmed theoretically using density functional theory. © 2015, Springer Science+Business Media New York.

Narula C.,Panjab University | Kaur I.,Central Scientific Instruments Organization CSIO | Kaur N.,Panjab University
Journal of Materials Science: Materials in Electronics | Year: 2014

The optical properties of mixed donor ligand directed semiconductor ZnO nanoparticles are evaluated and imine linked receptor is used as capping agents. The ZnO nanoparticles are prepared using precipitation method. The ligand is synthesized using condensation reaction between 2-aminothiophenol and 2-thiophenecarboxaldehyde. The formation of ligand is confirmed with spectroscopic methods including NMR and mass spectroscopy. However, UV–Vis absorption, photoluminescence, X-ray diffraction, energy dispersive X-ray and FTIR spectroscopy techniques are used for characterization of the ligand coated ZnO nanoparticles. The capping with ligand resulted in the successful amendment of the surface of ZnO nanoparticles, as it particularly reduced the defects related visible emission known as green luminescence and hence resulted in improvement in the UV luminescence. The UV–Vis absorption spectra also showed blue shift in the UV region for the ligand based ZnO nanoparticles due to the effect of quantum confinement. The composite (ZnO-ligands) stability is confirmed theoretically with Density Functional Theory. © 2014, Springer Science+Business Media New York.

Bhatnagar D.,Central Scientific Instruments Organization CSIO | Tuteja S.K.,Central Scientific Instruments Organization CSIO | Rastogi R.,Central Scientific Instruments Organization CSIO | Bharadwaj L.M.,Central Scientific Instruments Organization CSIO
BioNanoScience | Year: 2013

The synthesis of a network of cross-linked multiwalled carbon nanotubes (MWNTs) on a cysteamine-functionalized screen-printed gold electrode (MWNT/Au-SPE) and its use as a sensor for hemoglobin (Hb) determination is reported. It is proved to be a ready-to-use platform for routine clinical analysis in the blood after the separation of red blood cells. The study shows direct electron transfer between Hb-FeIII and Hb-FeII on applying a potential difference which is beneficial in detecting the presence of Hb in solution. The characterization of MWNT-embedded electrode was accomplished through Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy (EIS), Raman spectroscopy, optical profiling, and cyclic voltammetry. EIS studies show a reduction in the value of surface charge transfer resistance (R ct) from MWNT/Au-SPE (-2.72 kΩ) to bare Au-SPE (-24.38 kΩ), respectively. MWNT/Au-SPE showed better electrochemical characteristics, and kinetic studies revealed the heterogeneous rate transfer constant (k s) of 1.26 s-1. The electrochemically active surface area was also increased 100 times from bare Au-SPE (2.41 × 10-6 cm2) to MWNT/Au-SPE (2.052 × 10-4 cm2). The sensitivity of the sensor for Hb determination was found to be 20.50 μA g-1 dl in the linear range of 9-15 g dl-1 for lyophilized Hb. It is also found to be extremely sensitive for Hb determination in blood samples with 38.75 μA g-1 dl sensitivity in the same linear range. © 2013 Springer Science+Business Media New York.

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