Plasticizing Effect of K⁺ Ions and Succinonitrile on Electrical Conductivity of [Poly(ethylene oxide)–Succinonitrile]/KI–I₂ Redox-Couple Solid Polymer Electrolyte

Gupta, Ravindra Kumar,Rhee, Hee-Woo American Chemical Society 2013 The journal of physical chemistry. B, Condensed ma Vol.117 No.24

<P>The plasticizing effect of the K<SUP>+</SUP> ions and succinonitrile on the electrical conductivity of a new redox-couple solid polymer electrolyte system, (1 – <I>x</I>)[0.5poly(ethylene oxide):0.5succinonitrile]:<I>x</I>[0.9KI:0.1I<SUB>2</SUB>] with <I>x</I> = 0–0.2 in weight fraction, is reported. An increase of <I>x</I> resulted in an increase of the electrical conductivity (σ<SUB>25°C</SUB>) of the electrolyte. The electrolyte with <I>x</I> = 0.15 exhibited the highest σ<SUB>25°C</SUB> value, ∼7 × 10<SUP>–4</SUP> S cm<SUP>–1</SUP>, and is referred to as the optimum conducting composition (OCC). In addition to an increase of the mobile ion concentration with increasing <I>x</I>, X-ray diffractometry, Fourier-transform infrared spectroscopy, polarized optical microscopy, UV–vis spectroscopy, and differential scanning calorimetry studies revealed a decrease of poly(ethylene oxide) crystallinity/an increase of ionic mobility, indicating the plasticizing effect of the K<SUP>+</SUP> ions. Plasticizing and molecular diffusing properties of the succinonitrile further helped to improve the electrical conductivity of the electrolyte.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-24/jp4025798/production/images/medium/jp-2013-025798_0007.gif'></P>

Thermal, Micro-Structural, and Electrical Properties of a La1-xSrx Mn0.85Fe0.05Co0.05Ni0.05O3+δ (x = 0–0.4 Mole) Cathode System

Ravindra Kumar Gupta,김은이,김유항,황진명 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.6

The oxygen stoichiometry, thermal expansion, morphology, and electrical conductivity of a co-doped perovskitetype cathode system, La1-xSrx Mn0.85Fe0.05Co0.05 Ni0.05O3+ä (x = 0–0.4 mole), are studied for intermediate-temperature solid oxide fuel cell applications. Sr 2+ -doping led to a decrease in the unit cell volume, oxygen stoichiometry, particle size, and activation energy, and an increase in the coefficient of thermal expansion and electrical conductivity. The sample with x = 0.3 mole exhibited four to five fold weight loss with respect to La0.75Sr0.25 MnO3+δ at an intermediate temperature range and suggested the availability of a large number of oxygen vacancies due to a co-doping effect. This sample also showed sufficiently high electrical conductivity (~76 S cm −1 ) at 650 °C, a low activation energy (~0.15 eV), and a coefficient of thermal expansion (~12.1 × 10 −6 °C −1 ) comparable to those of the adjacent components and submicron sized particles. The experimental results are explained using defect models. The oxygen stoichiometry, thermal expansion, morphology, and electrical conductivity of a co-doped perovskitetype cathode system, La1-xSrx Mn0.85Fe0.05Co0.05 Ni0.05O3+ä (x = 0–0.4 mole), are studied for intermediate-temperature solid oxide fuel cell applications. Sr 2+ -doping led to a decrease in the unit cell volume, oxygen stoichiometry, particle size, and activation energy, and an increase in the coefficient of thermal expansion and electrical conductivity. The sample with x = 0.3 mole exhibited four to five fold weight loss with respect to La0.75Sr0.25 MnO3+δ at an intermediate temperature range and suggested the availability of a large number of oxygen vacancies due to a co-doping effect. This sample also showed sufficiently high electrical conductivity (~76 S cm −1 ) at 650 °C, a low activation energy (~0.15 eV), and a coefficient of thermal expansion (~12.1 × 10 −6 °C −1 ) comparable to those of the adjacent components and submicron sized particles. The experimental results are explained using defect models.

A Detailed Investigation into the Electrical Conductivity and Structural Properties of [Poly(ethylene oxide)-succinonitrile]-Li(CF3SO2)2N Solid Polymer Electrolytes

Ravindra Kumar Gupta,이희우 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.3

A solid polymer electrolyte (SPE) was prepared via a solution casting method from a blend of equal weight fractions of poly(ethylene oxide) (PEO) and succinonitrile, used as the polymer matrix, and a salt, Li(CF3SO2)2N (x = 0–0.3 in weight fraction). A plot of the electrical conductivity (σ25°C) vs. x showed an upturned U-shape, with the highest value being ~3.9 × 10−4 S/cm for x = 0.25 (EO/Li+ = 9.8; the optimum conducting composition). The electrolytes with x ranging from 0.15 to 0.3 showed a linear trend in their log(σT0.5) − (T−To)−1 curves with low pseudo-activation energy values, suggesting the presence of highly conductive amorphous domains, as confirmed by X-ray diffractometry measurements, Fourier-transform infrared (FT-IR) spectroscopy, polarized optical microscopy, and differential scanning calorimetry studies. The change in PEO chain conformation with x is discussed in detail using FT-IR spectroscopy in the light of earlier results reported for PEO − Li(CF3SO2)2N SPEs.

Evaluation of Somaclonal Variation for Genetic Improvement of Patchouli ($Pogostemon$ $patchouli$), an Exclusively Vegetatively Propagated Aromatic Plant

Ravindra, Nagawara Seshagirirao,Ramesh, Srinivas Iyer,Gupta, Mahesh Kumar,Jhang, Tripta,Shukla, Ashutosh Kumar,Darokar, Mahendra Pandurang,Kulkarni, Raghavendra Narayanrao 한국작물학회 2012 Journal of crop science and biotechnology Vol.15 No.1

Patchouli ($Pogostemon$ $patchouli$) is an important, exclusively vegetatively propagated aromatic plant, whose essential oil is widely used in perfumery and cosmetic products. Forty $SC_1$ generation (first generation following $in$ $vitro$ phase) somaclones selected randomly from about 400 somaclones developed from the variety Johore, were multiplied through stem cuttings and evaluated in $SC_2$ and $SC_3$ generations to study the extent of somaclonal variation generated for plant height, herb yield, essential oil content, essential oil yield, and seven constituents of the essential oil. Significant or highly significant somaclonal variation was observed for plant height, herb yield, essential oil content, essential oil yield, and contents of patchouli alcohol, ${\alpha}$-guaiene, ${\alpha}$,${\delta}$-patchoulene, and ${\alpha}$-bulnesene in the essential oil. The number of somaclones significantly superior to the parental variety for plant height, herb yield, essential oil content, and patchouli alcohol content in the essential oil ranged from 8 - 16 and the maximum superiority over the parental variety for these traits ranged from 21 - 79%. Broad-sense heritability estimates of plant height, herb yield, and essential oil content were 0.60 - 0.70 while those of essential oil yield and patchouli alcohol content were 0.44 and 0.47, respectively. Heritability estimates of other studied essential oil constituents were generally low (0.12 - 0.38). A high positive correlation was observed between essential oil yield and herb yield suggesting that selection for herb yield would be effective in improving essential oil yield. Patchouli alcohol content in the essential oil was negatively correlated with all the studied traits. Somaclonal variation, heritabilities of traits, and inter-trait correlations are reported for the first time in patchouli.

Evaluation of Somaclonal Variation for Genetic Improvement of Patchouli (Pogostemon patchouli), an Exclusively Vegetatively Propagated Aromatic Plant

Nagawara Seshagirirao Ravindra,Srinivas Iyer Ramesh,Mahesh Kumar Gupta,Tripta Jhang,Ashutosh Kumar Shukla,Mahendra Pandurang Darokar,Raghavendra Narayanrao Kulkarni 한국작물학회 2012 Journal of crop science and biotechnology Vol.15 No.1

Patchouli (Pogostemon patchouli) is an important, exclusively vegetatively propagated aromatic plant, whose essential oil is wide-ly used in perfumery and cosmetic products. Forty SC 1 generation (first generation following in vitro phase) somaclones selected ran-domly from about 400 somaclones developed from the variety Johore, were multiplied through stem cuttings and evaluated in SC 2and SC 3 generations to study the extent of somaclonal variation generated for plant height, herb yield, essential oil content, essential oil yield, and seven constituents of the essential oil. Significant or highly significant somaclonal variation was observed for plant height, herb yield, essential oil content, essential oil yield, and contents of patchouli alcohol, α-guaiene, α,δ-patchoulene, and α-bul-nesene in the essential oil. The number of somaclones significantly superior to the parental variety for plant height, herb yield, essen-tial oil content, and patchouli alcohol content in the essential oil ranged from 8 - 16 and the maximum superiority over the parental variety for these traits ranged from 21 - 79%. Broad-sense heritability estimates of plant height, herb yield, and essential oil content were 0.60 - 0.70 while those of essential oil yield and patchouli alcohol content were 0.44 and 0.47, respectively. Heritability esti-mates of other studied essential oil constituents were generally low (0.12 - 0.38). A high positive correlation was observed between essential oil yield and herb yield suggesting that selection for herb yield would be effective in improving essential oil yield. Patchouli alcohol content in the essential oil was negatively correlated with all the studied traits. Somaclonal variation, heritabilities of traits,and inter-trait correlations are reported for the first time in patchouli.

A randomized prospective study comparing acute toxicity, compliance and objective response rate between simultaneous integrated boost and sequential intensity-modulated radiotherapy for locally advanced head and neck cancer

Akanksha Grover,Tej Prakash Soni,Nidhi Patni,Dinesh Kumar Singh,Naresh Jakhotia,Anil Kumar Gupta,Lalit Mohan Sharma,Shantanu Sharma,Ravindra Singh Gothwal 대한방사선종양학회 2021 Radiation Oncology Journal Vol.39 No.1

Purpose: Intensity-modulated radiotherapy (IMRT) provides higher dose to target volumes and limits the dose to normal tissues. IMRT may be applied using either simultaneous integrated boost (SIB-IMRT) or sequential boost (SEQ-IMRT) technique. The objectives of this study were to compare acute toxicity and objective response rates between SIB-IMRT and SEQ-IMRT in patients with locally advanced head and neck cancer. Materials and Methods: Total 110 patients with locally advanced carcinoma of oropharynx, hypopharynx, and larynx were randomized equally into the two arms (SIB-IMRT vs. SEQ-IMRT). Patients in SIB-IMRT arm received dose of 66 Gy in 30 fractions, 5 days a week, over 6 weeks. SEQ-IMRT arm’s patients received 70 Gy in 35 fractions over 7 weeks. Weekly concurrent cisplatin chemotherapy was given in both arms. Patients were assessed for acute toxicities during the treatment and for objective response at 3 months after the radiotherapy. Results: Grade 3 dysphagia was significantly more with SIB-IMRT compared to SEQ-IMRT (72% vs. 41.2%; p = 0.006) but other toxicities including mucositis, dermatitis, xerostomia, weight-loss, incidence of nasogastric tube intubation and hospitalization for supportive management were similar in both the arms. Patients in SIB-IMRT arm showed better treatment-compliance and had significantly less treatment-interruption compared to SEQ-IMRT arm (p = 0.028). Objective response rates were similar in both the arms (p = 0.783). Conclusion: Concurrent chemoradiation with SIB-IMRT for locally advanced head and neck cancer is well-tolerated and results in better treatment-compliance, similar objective response rates, comparable incidence of mucositis and higher incidence of grade 3 dysphagia compared to SEQ-IMRT.