Graphene oxide crosslinked poly(phenylene oxide) nanocomposite as high-performance anion-conducting membrane

Gautam Das,강동호,김채연,윤현희 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-

Anion conducting nanocomposite membranes were synthesized by crosslinking quaternized poly(phenylene oxide) with 1,4-diazabicyclo[2.2.2]octane modified graphene oxide (QGO). FTIR, SEM, AFMand TEM were used to study the functionalization, structure, and morphology of the membranes. Theeffect of QGO on ionic conductivity, water uptake, and swelling ratio were studied in detail. Thenanocomposite membrane exhibited an ionic conductivity of90 mS cm 1 at 25 C and reached151 mS cm 1 at 80 C owing to good microphase separation. A power density of 5.2 mW cm 2 at 60 C forurea/O2 fuel cell was obtained using the nanocomposite membrane.

Poly(vinyl alcohol)/Silica Nanoparticles Based Anion-Conducting Nanocomposite Membrane for Fuel-Cell Applications

Das Gautam,윤영수,Biplab Kr. Deka,이석희,박영빈 한국고분자학회 2015 Macromolecular Research Vol.23 No.3

Organic-inorganic heterogeneous hybrid anion conducting membranes were prepared by 1,4-diglycidylbutane ether (DGBE) aided chemical grafting of silica (SiO2) nanoparticles onto poly(vinyl alcohol) (PVA). Themembranes properties such as water uptake, thermo-mechanical attributes and ionic conductivity with respect toDGBE and SiO2 loadings were studied extensively. The membrane with composition of 15 wt% DGBE and 3 wt%of SiO2 enhances the tensile strength of PVA by 229%. The ionic conductivity of the membranes was observed tobe in the range of 10-4-10-3 Scm-1 under 100% relative humidity. A linear increase in the ionic conductivity with temperaturewas demonstrated by all the membranes. The PVA nanocomposites appeared to be a potential candidate forapplication in alkaline fuel cell.

A Proton Conducting Composite Membrane based on Polyvinyl Alcohol and Polyaniline-intercalated Graphene Oxide

Gautam Das,강동호,윤현희 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.4

A novel proton conducting membrane was synthesized based on a composite of polyvinyl alcohol (PVA) and sulfonated polyaniline-intercalated graphene oxide (SPANi-GO). The synthesized membranes were characterized by tensile strength measurement, thermo-gravimetric analysis, scanning electron microscopy, XRD and FTIR techniques. The effect of SPANi-GO on the proton conductivity of the PVA based membrane (PVA/SPANi-GO) was studied. The nanocomposite membrane exhibited an impressive ionic conductivity of 0.129 Scm−1 at 25°C. Further, the membranes showed excellent thermal and mechanical properties. The water content of the pristine as well as the nanocomposites membrane was found to be in the range of 42–52%. The results indicate that the simply prepared PVA/SPANi-GO is a promising proton conducting membrane for practical applications.

Evaluation of the Efficacy of Methylprednisolone, Etoricoxib and a Combination of the Two Substances to Attenuate Postoperative Pain and PONV in Patients Undergoing Laparoscopic Cholecystectomy: A Prospective, Randomized, Placebo-controlled Trial

Gautam, Sujeet,Agarwal, Amita,Das, Pravin Kumar,Agarwal, Anil,Kumar, Sanjay,Khuba, Sandeep The Korean Pain Society 2014 The Korean Journal of Pain Vol.27 No.3

Background: Establishment of laparoscopic cholecystectomy as an outpatient procedure has accentuated the clinical importance of reducing early postoperative pain, as well as postoperative nausea and vomiting (PONV). We therefore planned to evaluate the role of a multimodal approach in attenuating these problems. Methods: One hundred and twenty adult patients of ASA physical status I and II and undergoing elective laparoscopic cholecystectomy were included in this prospective, randomized, placebo-controlled study. Patients were divided into four groups of 30 each to receive methylprednisolone 125 mg intravenously or etoricoxib 120 mg orally or a combination of methylprednisolone 125 mg intravenously and etoricoxib 120 mg orally or a placebo 1 hr prior to surgery. Patients were observed for postoperative pain, fentanyl consumption, PONV, fatigue and sedation, and respiratory depression. Results were analyzed by the ANOVA, a Chi square test, the Mann Whitney U test and by Fisher's exact test. P values of less than 0.05 were considered to be significant. Results: Postoperative pain and fentanyl consumption were significantly reduced by methylprednisolone, etoricoxib and their combination when compared with placebo (P<0.05). The methylprednisolone + etoricoxib combination caused a significant reduction in postoperative pain and fentanyl consumption as compared to methylprednisolone or etoricoxib alone (P<0.05); however, there was no significant difference between the methylprednisolone and etoricoxib groups (P>0.05). The methylprednisolone and methylprednisolone + etoricoxib combination significantly reduced the incidence and severity of PONV and fatigue as well as the total number of patients requiring an antiemetic treatment compared to the placebo and etoricoxib (P<0.05). Conclusions: A preoperative single-dose administration of a combination of methylprednisolone and etoricoxib reduces postoperative pain along with fentanyl consumption, PONV, antiemetic requirements and fatigue more effectively than methylprednisolone or etoricoxib alone or a placebo.

Prevention of epidural catheter migration: a comparative evaluation of two tunneling techniques

Gautam Sujeet,Agarwal Anil,Das Pravin Kumar,Khuba Sandeep,Kumar Sanjay 대한마취통증의학회 2021 Korean Journal of Anesthesiology Vol.74 No.1

BackgroundEpidural analgesia failure episodes can be reduced by catheter fixation techniques with a lower incidence of catheter migration. In this clinical study, we compared the roles of two epidural catheter tunneling techniques for the prevention of epidural catheter migration.MethodsPatients undergoing major abdominal surgery were randomized into three groups of 50 patients each based on the method used to secure the epidural catheter. In the control group (CG), the epidural catheter was secured without tunneling. Tunneling groups 1 and 2 (TG1 and TG2) were defined as tunneling with and without a catheter loop, respectively. The primary outcome measure was the migration of the epidural catheter, while the secondary outcome measures were the adequacy of analgesia and signs of inflammation. All patients were followed up by the acute pain service team twice daily in the postoperative period until the epidural catheter was removed. The results were analyzed by the one-way analysis of variance (ANOVA), chi-square test, and Fisher’s exact test. P values <0.050 were considered significant.ResultsThe three groups were similar with respect to patient characteristics. Catheter migration was significantly reduced in TG2 (two patients) compared to those in the other two groups, i.e., TG1 (eight patients) (P = 0.045) and CG (17 patients) (P = 0.001). No differences were found amongst the three groups in analgesia adequacy and catheter site inflammation (P > 0.050).ConclusionsCatheter migration was significantly reduced by tunneling without a catheter loop in TG2 as compared to the other two groups. Therefore, we suggest routine use of tunneling without a catheter loop technique in anesthesia practice and look forward to future studies with larger sample sizes.

Validation and Marker-Assisted Selection of Stem Rust Resistance Gene Sr2 in Indian Wheat Using Gel-Based and Gel-Free Methods

Gautam Vishwakarma,Ravi Prakash Sanyal,Abhijit Shitre,D. A. Gadekar,Ajay Saini,Bikram Kishore Das 한국작물학회 2019 Journal of crop science and biotechnology Vol.22 No.4

Stem rust resistance gene Sr2 is an important slow-rusting gene which has provided resistance against stem rust for many years. The Sr2 gene has durable resistance against all stem rust pathogens including the Ug99 group of races. It shows recessive inheritance and is linked with two phenotypic markers, Pseudo Black Chaff (PBC) and High Temperature-Induced Seedling Chlorosis (HTISC). However, direct screening as well as phenotypic marker-based screening for selection of Sr2 is difficult due to the effect of environmental factors and genetic background. Microsatellite marker Xgwm533 linked to Sr2 gene is useful for rapid screening of large populations. Here we report validation and use of Xgwm533 for screening 21 wheat lines and 24 wheat genotypes for the presence of the Sr2 gene. Furthermore, we also report the presence of a new, smaller allele (97 bp) of Xgwm533 locus in a few genotypes that was also confirmed by sequencing. We also demonstrate a new SYBR green dye, melt-curve/profile-based assay for convenient screening of the Xgwm533 locus, where the presence of different alleles can be differentiated in a gel-free manner.

Review Article : Evaluation of the Efficacy of Methylprednisolone, Etoricoxib and a Combination of the Two Substances to Attenuate Postoperative Pain and PONV in Patients Undergoing Laparoscopic Cholecystectomy: A Prospective, Randomized, Placebo-controll

( Sujeet Gautam ),( Amita Agarwal ),( Pravin Kumar Das ),( Anil Agarwal ),( Sanjay Kumar ),( Sandeep Khuba ) 대한통증학회 2014 The Korean Journal of Pain Vol.27 No.3

Background: Establishment of laparoscopic cholecystectomy as an outpatient procedure has accentuated the clinical importance of reducing early postoperative pain, as well as postoperative nausea and vomiting (PONV). We therefore planned to evaluate the role of a multimodal approach in attenuating these problems. Methods: One hundred and twenty adult patients of ASA physical status I and II and undergoing elective laparoscopic cholecystectomy were included in this prospective, randomized, placebo-controlled study. Patients were divided into four groups of 30 each to receive methylprednisolone 125 mg intravenously or etoricoxib 120 mg orally or a combination of methylprednisolone 125 mg intravenously and etoricoxib 120 mg orally or a placebo 1 hr prior to surgery. Patients were observed for postoperative pain, fentanyl consumption, PONV, fatigue and sedation, and respiratory depression. Results were analyzed by the ANOVA, a Chi square test, the Mann Whitney U test and by Fisher`s exact test. P values of less than 0.05 were considered to be significant. Results: Postoperative pain and fentanyl consumption were significantly reduced by methylprednisolone, etoricoxib and their combination when compared with placebo (P<0.05). The methylprednisolone + etoricoxib combination caused a significant reduction in postoperative pain and fentanyl consumption as compared to methylprednisolone or etoricoxib alone (P<0.05); however, there was no significant difference between the methylprednisolone and etoricoxib groups (P>0.05). The methylprednisolone and methylprednisolone + etoricoxib combination significantly reduced the incidence and severity of PONV and fatigue as well as the total number of patients requiring an antiemetic treatment compared to the placebo and etoricoxib (P<0.05). Conclusions: A preoperative single-dose administration of a combination of methylprednisolone and etoricoxib reduces postoperative pain along with fentanyl consumption, PONV, antiemetic requirements and fatigue more effectively than methylprednisolone or etoricoxib alone or a placebo

Evaluation of the Efficacy of Methylprednisolone, Etoricoxib and a Combination of the Two Substances to Attenuate Postoperative Pain and PONV in Patients Undergoing Laparoscopic Cholecystectomy: A Prospective, Randomized, Placebo-controlled Trial

Sujeet Gautam,Amita Agarwal,Pravin Kumar Das,Anil Agarwal,Sanjay Kumar,Sandeep Khuba 대한통증학회 2014 The Korean Journal of Pain Vol.27 No.3

Background: Establishment of laparoscopic cholecystectomy as an outpatient procedure has accentuated the clinical importance of reducing early postoperative pain, as well as postoperative nausea and vomiting (PONV). We therefore planned to evaluate the role of a multimodal approach in attenuating these problems. Methods: One hundred and twenty adult patients of ASA physical status I and II and undergoing elective laparoscopic cholecystectomy were included in this prospective, randomized, placebo-controlled study. Patients were divided into four groups of 30 each to receive methylprednisolone 125 mg intravenously or etoricoxib 120 mg orally or a combination of methylprednisolone 125 mg intravenously and etoricoxib 120 mg orally or a placebo 1 hr prior to surgery. Patients were observed for postoperative pain, fentanyl consumption, PONV, fatigue and sedation, and respiratory depression. Results were analyzed by the ANOVA, a Chi square test, the Mann Whitney U test and by Fisher’s exact test. P values of less than 0.05 were considered to be significant. Results: Postoperative pain and fentanyl consumption were significantly reduced by methylprednisolone, etoricoxib and their combination when compared with placebo (P<0.05). The methylprednisolone + etoricoxib combination caused a significant reduction in postoperative pain and fentanyl consumption as compared to methylprednisolone or etoricoxib alone (P<0.05); however, there was no significant difference between the methylprednisolone and etoricoxib groups (P>0.05). The methylprednisolone and methylprednisolone + etoricoxib combination significantly reduced the incidence and severity of PONV and fatigue as well as the total number of patients requiring an antiemetic treatment compared to the placebo and etoricoxib (P<0.05). Conclusions: A preoperative single-dose administration of a combination of methylprednisolone and etoricoxib reduces postoperative pain along with fentanyl consumption, PONV, antiemetic requirements and fatigue more effectively than methylprednisolone or etoricoxib alone or a placebo.

Outward growth of Archean Singbhum Craton, India during Neoarchean to Paleoproterozoic time

Kaushik Das,Gautam Ghosh,Sankar Bose 대한지질학회 2019 대한지질학회 학술대회 Vol.2019 No.10

Proton-conducting Membrane Based on Epoxy Resin-poly(vinyl alcohol)-sulfosuccinic Acid Blend and Its Nanocomposite with Sulfonated Multiwall Carbon Nanotubes for Fuel-cell Application

Kakati Nitul,Gautam Das,윤영수 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.2

A blend of poly(vinyl alcohol) (PVA) with diglycidyl ether of bisphenol-A (DGB) in the presence of sulfosuccinic acid (SSA) was investigated as hydrolytically-stable proton-conducting membrane. The PVA modification was carried out by varying the DGB:SSA ratio (20:20, 10:20, and 5:20). A nanocomposite of the blend (20:20) was prepared with sulfonated multiwall carbon nanotubes (viz., 1, 3 and 5 wt%). The water uptake behavior and the proton conductivity of the prepared membranes were evaluated. The ionic conductivity of the membranes and the water uptake behavior depended on the s-MWCNT and the DGB contents. The ionic conductivity showed an enhancement for the blend and for the nanocomposite membrane as compared to the pristine polymer.