Mechanically viscoelastic nanoreinforced hybrid hydrogels composed of polyacrylamide, sodium carboxymethylcellulose, graphene oxide, and cellulose nanocrystals

Kumar, Anuj,Rao, Kummara Madhusudana,Han, Sung Soo Elsevier 2018 Carbohydrate Polymers Vol.193 No.-

<P><B>Abstract</B></P> <P>Polyacrylamide-sodium carboxymethylcellulose (PMC) hybrid hydrogels reinforced with graphene oxide (GO) and/or cellulose nanocrystals (CNCs) were prepared <I>via in situ</I> free-radical polymerization. In this work, GO nanosheets were freshly synthesized by modified Hummer’s method alongwith the aqueous suspension of CNCs by acid-hydrolysis. In addition, the effect of GO content (1.5 wt%) and CNCs (from 2.5 wt% to 10.0 wt%) was investigated in these quaternary hydrogels. The results showed good pseudo-plastic behavior, self-healing ability, mechanical performance, and shape-recovery behavior of the hybrid hydrogels reinforced with GO and CNCs content. PMC-GO1.5/CNCs10.0 hybrid hydrogel showed 110.5 kPa as compressive strength and stiffness value of 887.7 N/m (at 30% strain). Moreover, the synergistic effect of both GO and CNCs as nanoreinforcements in hydrogels provides a new point of view for the preparation of hybrid hydrogels having exceptional structural and mechanical properties. As-obtained hybrid hydrogels may have potential application in tissue engineering for tunable mechanical properties.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mechanically viscoelastic hybrid hydrogels are achieved using One-Pot synthesis. </LI> <LI> Multifunctional synergistic GO/CNCs crosslinking is improved. </LI> <LI> A quaternary-network hydrogel reaction mechanism is presented. </LI> <LI> Excellent rheological and mechanical properties are observed. </LI> <LI> Shape-recovery and self-healing behavior are advantageous for tissue engineering. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Application of xanthan gum as polysaccharide in tissue engineering: A review

Kumar, Anuj,Rao, Kummara Madhusudana,Han, Sung Soo Elsevier 2018 Carbohydrate Polymers Vol.180 No.-

<P><B>Abstract</B></P> <P>Xanthan gum is a microbial high molecular weight exo-polysaccharide produced by <I>Xanthomonas</I> bacteria (a Gram-negative bacteria genus that exhibits several different species) and it has widely been used as an additive in various industrial and biomedical applications such as food and food packaging, cosmetics, water-based paints, toiletries, petroleum, oil-recovery, construction and building materials, and drug delivery. Recently, it has shown great potential in issue engineering applications and a variety of modification methods have been employed to modify xanthan gum as polysaccharide for this purpose. However, xanthan gum-based biomaterials need further modification for several targeted applications due to some disadvantages (e.g., processing and mechanical performance of xanthan gum), where modified xanthan gum will be well suited for tissue engineering products. In this review, the current scenario of the use of xanthan gum for various tissue engineering applications, including its origin, structure, properties, modification, and processing for the preparation of the hydrogels and/or the scaffolds is precisely reviewed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Xanthan gum is a microbial high molecular weight exo-polysaccharide. </LI> <LI> It has excellent biocompatibility and pseudo-plastic behavior. </LI> <LI> Shear-thinning and gelling behaviors of XG are more beneficial in tissue engineering. </LI> <LI> Recent trends on XG-based biomaterials in tissue engineering are reviewed. </LI> <LI> It shows a quite promising future as a biopolymer in tissue engineering. </LI> </UL> </P>

Hazardous As(III) removal using nanoporous activated carbon of waste garlic stem as adsorbent: Kinetic and mass transfer mechanisms

Anuj Kumar Prajapati,Monoj Kumar Mondal 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.11

Nanoporous activated garlic stem carbon (AGSC) was prepared from garlic stem waste and used to remove As(III)from synthetic water under complete batch experiments. Characterization studies of AGSC were performed by FTIR, SEM, EDX, BET, XPS and XRD techniques. Batch adsorption experiments were carried out to study the adsorption of As(III) onto AGSC. Maximum removal of 93.3% of As(III) was obtained at optimum condition of pH 6, the adsorbent dose 5 g/L, equilibrium time 150 min, initial As(III) concentration 400 μg/L and temperature 298 K. Both Langmuir and Temkin isotherm model fitted well to the experimental data as compared to Freundlich isotherm. Kinetics indicated that the adsorption of As(III) was more suitable for pseudo-second-order than pseudo-first-order and Elovich model. The mass transfer mechanism could be described by Weber-Morris and Boyd mass transfer model. The maximum adsorption capacity of AGSC for As(III) removal was found to be 192.30 μg/g. The negative enthalpy and free energy change indicated that the adsorption process of As(III) onto AGSC was exothermic and spontaneous. The negative value of entropy change suggested decreasing randomness at the AGSC-aqueous As(III) interface during As(III) adsorption.

Study of oxygen reduction reaction on binuclear-phthalocyanine with Fe-Fe, Co-Co, and Fe-Co dual-atom-active sites using density functional theory

Anuj Kumar,Dipak Kumar Das,Raj Kishore Sharma,Manickam Selvaraj,Mohammed A. Assiri,Saira Ajmal,Guoxin Zhang,Ram K. Gupta,Ghulam Yasin 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.123 No.-

Although the N4-macrocyclic ligands have been used to develop single-atom catalysts (SACs), their utilizationfor the construction of dual-atom catalysts (DACs) for electrocatalytic oxygen reduction reaction(ORR) is poorly investigated. Herein, a binuclear phthalocyanine (bN-Pc) was explored as a theoreticalmodel for the construction of FeFe-bN-Pc, CoCo-bN-Pc, and FeCo-bN-Pc dual-atom-site configurationsand their ORR activity along with mechanisms were investigated systematically in alkaline media, usingdensity functional theory (DFT) calculations. The results indicated that the dual-atom-bN-Pc models, havingclose proximity between adjacent metals, invited individual O-atom of O2 for coordination on bothsites, forming a cis-bridged-O2 adduct. The Gibbs free energy studies showed that the decompositionof O2 on dual-atom sites was the rate-determining step, and the Fe-Co-bN-Pc had a lower energy barrier(0.591 eV) for this step as compared to Fe-Fe-bN-Pc (0.641 eV) and Co-Co-bN-Pc (0.692 eV), which justifiesits stronger ORR performance. The synergistic effect of Fe-Co collaboration, the close proximity ofFe-Co, and the significant e- donation from the 3d-orbital of active sites into the *orbital of O2 can beattributed to this decrease in limiting the potential for the rate-determining step on Fe-Co-bN-Pc. Forfuture ORR electrocatalysts, this work offers a scientific and engineering perspective on the constructionof dual-atom active sites employing molecular moieties.

Bioactive glass-modified halloysite nanotubesreinforced hybrid hydrogels for hard tissue regeneration

( Anuj Kumar ),( Ankur Sood ),한성수 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-

Assessment of DP Threshold and its Test–Retest Reliability in Normal Hearing Individuals

Anuj Kumar Neupane,Kalpesh Bheda,Gunjan Mehta 한국언어재활사협회 2024 Clinical Archives of Communication Disorders Vol.8 No.3

Density functional theory and time‐dependent density functional theory studies on optoelectronic properties of fused heterocycles with cyclooctatetraene

Kumar Vipin,Tripathi Anuj,Choi Seyong,Chitumalla Ramesh Kumar,서지연,장준경,Chetti Prabhakar 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.7

We establish a structure–property relation for the system having a cyclooctatetraene (COT) ring fused with four five-membered heterocyclic rings. The two five-membered heterocycles selected are furan and selenophene and their fused structure with COT is known as cyclooctatetrafuran (COF) and cyclooctatetraselenophene (COSe), respectively. We found 15 geometrical isomers of each COF and COSe and their structural stability and optoelectronic properties have been evaluated by quantum chemical simulations. The density functional theory (DFT) and time-dependent DFT simulations were employed for a systematic review of all isomers. Electronic excitations, hole reorganization energies, electron reorganization energies, ionization potentials, and electron affinities, of all the isomers, were reported. Based on our comparative study, it is shown that one of the isomers is suggested as a better charge transport material.

Elliptic Curve Signcryption Based Security Protocol for RFID

( Anuj Kumar Singh ),( B. D. K. Patro ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.1

Providing security has been always on priority in all areas of computing and communication, and for the systems that are low on computing power, implementing appropriate and efficient security mechanism has been a continuous challenge for the researchers. Radio Frequency Identification (RFID) system is such an environment, which requires the design and implementation of efficient security mechanism. Earlier, the security protocols for RFID based on hash functions and symmetric key cryptography have been proposed. But, due to high strength and requirement of less key size in elliptic curve cryptography, the focus of researchers has been on designing efficient security protocol for RFID based on elliptic curves. In this paper, an efficient elliptic curve signcryption based security protocol for RFID has been proposed, which provides mutual authentication, confidentiality, non-repudiation, integrity, availability, forward security, anonymity, and scalability. Moreover, the proposed protocol successfully provides resistance from replay attack, impersonation attack, location tracking attack, de-synchronization attack, denial of service attack, man-in-the-middle attack, cloning attack, and key-compromise attack. Results have revealed that the proposed protocol is efficient than the other related protocols as it takes less computational time and storage cost, especially for the tag, making it ideal to be used for RFID systems.

Synthesis, Structural Details and Induction of Superconductivity in Ga<SUB>1-x</SUB>Pb<SUB>x</SUB>Sr₂Y<SUB>1-y</SUB>Ca<SUB>y</SUB>CU₂O₇ (x=0.0 to 0.6 & y=0.0 to 0.5)

Shiva Kumar,Anuj Kumar,V.P.S. Awana,H. Kishan 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Weekly cisplatin or gemcitabine concomitant with radiation in the management of locally advanced carcinoma cervix: results from an observational study

Arun K Verma,Ashok Kumar Arya,Milind Kumar,Anuj Kumar,Sweety Gupta,DN Sharma,GK Rath 대한부인종양학회 2009 Journal of Gynecologic Oncology Vol.20 No.4

Objective: The use of non-platinum drugs in concurrent chemoradiation in carcinoma cervix has not been well explored and hence a two arm study was planned to compare the outcome of concomitant cisplatin or gemcitabine in locally advanced carcinoma cervix. Methods: Thirty six patients were evaluated in this study for response rates and complications. These patients were divided into two arms, sixteen patients in the cisplatin arm and twenty patients in the gemcitabine arm. Cisplatin and gemcitabine were given as i.v. infusion at doses of 40 mg/㎡ and 150 mg/㎡ respectively for five weeks concomitant with radiotherapy. All patients had received pelvic radiotherapy to a dose of 50 Gy/25 fraction/5 weeks by four field box technique followed by high-dose-rate brachytherapy (3 sessions, each of 7.5 Gy to point A). Results: Median follow up was of 10.4 months (range, 3 to 36 months) and 10.9 months (range, 2 to 49 months) in the cisplatin and gemcitabine arms, respectively. At first follow up, 68.8% in the cisplatin arm and 70% in the gemcitabine arm had achieved complete response (p=0.93). Similar response rates were noted in different stages in both arms. None of the patients except one developed grade 4 toxicity. Similar toxicity profiles were observed in both arms. Local disease control, distant disease free survival and overall survival was 68.8% vs. 70%, 93.8% vs. 85%, 68.8% vs. 60% in the cisplatin and gemcitabine arms, respectively. Conclusion: Weekly gemcitabine had similar disease control and tolerable toxicity profile with cisplatin. Gemcitabine may be used as an alternative to cisplatin in patients with compromised renal function. Objective: The use of non-platinum drugs in concurrent chemoradiation in carcinoma cervix has not been well explored and hence a two arm study was planned to compare the outcome of concomitant cisplatin or gemcitabine in locally advanced carcinoma cervix. Methods: Thirty six patients were evaluated in this study for response rates and complications. These patients were divided into two arms, sixteen patients in the cisplatin arm and twenty patients in the gemcitabine arm. Cisplatin and gemcitabine were given as i.v. infusion at doses of 40 mg/㎡ and 150 mg/㎡ respectively for five weeks concomitant with radiotherapy. All patients had received pelvic radiotherapy to a dose of 50 Gy/25 fraction/5 weeks by four field box technique followed by high-dose-rate brachytherapy (3 sessions, each of 7.5 Gy to point A). Results: Median follow up was of 10.4 months (range, 3 to 36 months) and 10.9 months (range, 2 to 49 months) in the cisplatin and gemcitabine arms, respectively. At first follow up, 68.8% in the cisplatin arm and 70% in the gemcitabine arm had achieved complete response (p=0.93). Similar response rates were noted in different stages in both arms. None of the patients except one developed grade 4 toxicity. Similar toxicity profiles were observed in both arms. Local disease control, distant disease free survival and overall survival was 68.8% vs. 70%, 93.8% vs. 85%, 68.8% vs. 60% in the cisplatin and gemcitabine arms, respectively. Conclusion: Weekly gemcitabine had similar disease control and tolerable toxicity profile with cisplatin. Gemcitabine may be used as an alternative to cisplatin in patients with compromised renal function.