Room temperature chemical synthesis of Cu(OH)₂ thin films for supercapacitor application

Gurav, K.V.,Patil, U.M.,Shin, S.W.,Agawane, G.L.,Suryawanshi, M.P.,Pawar, S.M.,Patil, P.S.,Lokhande, C.D.,Kim, J.H. Elsevier Sequoia 2013 Journal of alloys and compounds Vol.573 No.-

Room temperature soft chemical synthesis route is used to grow nanograined copper hydroxide [Cu(OH)<SUB>2</SUB>] thin films on glass and stainless steel substrates. The structural, morphological, optical and wettability properties of Cu(OH)<SUB>2</SUB> thin films are studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), UV-vis spectrophotometer and water contact angle measurement techniques. The results showed that, room temperature chemical synthesis route allows to form the nanograined and hydrophilic Cu(OH)<SUB>2</SUB> thin films with optical band gap energy of 3.0eV. The electrochemical properties of Cu(OH)<SUB>2</SUB> thin films are studied in an aqueous 1M NaOH electrolyte using cyclic voltammetry. The sample exhibited supercapacitive behavior with 120F/g specific capacitance.

One-pot exploitation of chitin biomass for simultaneous production of electricity, n-acetylglucosamine and polyhydroxyalkanoates in microbial fuel cell using novel marine bacterium <i>Arenibacter palladensis</i> YHY2

Gurav, Ranjit,Bhatia, Shashi Kant,Moon, Yu-Mi,Choi, Tae-Rim,Jung, Hye-Rim,Yang, Soo-Yeon,Song, Hun-Suk,Jeon, Jong-Min,Yoon, Jeong-Jun,Kim, Yun-Gon,Yang, Yung-Hun Elsevier 2019 JOURNAL OF CLEANER PRODUCTION Vol.209 No.-

<P><B>Abstract</B></P> <P>A novel marine bacterium <I>Arenibacter palladensis</I> YHY2 isolated from Eastern Sea, South Korea revealed hydrolysing ability of crab chitin in shake flask and microbial fuel cell (MFC) systems. Under shake flask cultivation, strain YHY2 demonstrated 71.44 ± 1.90 U/ml chitinase activity with the microbial cell optical density (OD) 0.699 ± 0.021. High performance liquid chromatography (HPLC) results showed N-acetylglucosamine (GlcNAc) as the major by-product of chitin degradation. Furthermore, <I>Ralstonia eutropha</I> H16 which has carbon utilization limited to GlcNAc and fructose was co-cultivated with YHY2 to consume GlcNAc and accumulate polyhydroxyalkanoates (PHA). However, on co-cultivating strain YHY2 with H16 surprisingly showed higher production of chitinase (97.89 ± 2.72 U/ml) and GlcNAc (80.31 mg GlcNAc/g chitin) corresponding to the microbial cell OD (1.065 ± 0.005) at 120 h. In addition, marine strain YHY2 demonstrated biofilm formation, hence co-cultivation of strain YHY2 and H16 under MFC system was performed to check the electricity production. Maximum electricity current output density was 15.15 μA/cm<SUP>2</SUP> at the initial stage and 10.72 μA/cm<SUP>2</SUP> at 204 h. GlcNAc (196.34 mg GlcNAc/g chitin) was produced along with other metabolites like butyrate, acetate, lactate, and propionate in MFC system. The microbial cell biomass from MFC was analysed for PHA content showed 1.020 g/l of 3-polyhydroxybutyrate (PHB) and 0.198 g/l of 3-polyhydroxyvalerate (PHV) as the main components of PHA. Moreover, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were performed to reveal changes in chitin before and after degradation. Thus, the exploitation of recalcitrant chitin biomass for simultaneous production of GlcNAc, electricity, and PHA in one-pot MFC system was the productive asset for sustainable development.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Coastal soil harbours <I>Arenibacter palladensis</I> YHY2 capable of hydrolysing chitin. </LI> <LI> YHY2 produced electricity in MFC using chitin biomass as a sole source of carbon. </LI> <LI> Co-cultivation of YHY2 with GlcNAc utilizing <I>Ralstonia eutropha</I> H16 accumulated PHA. </LI> <LI> First report on one-pot bioconversion of chitin into electricity, GlcNAc and PHA. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

De-Centralized Information Flow Control for Cloud Virtual Machines with Blowfish Encryption Algorithm

Gurav, Yogesh B.,Patil, Bankat M. International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.12

Today, the cloud computing has become a major demand of many organizations. The major reason behind this expansion is due to its cloud's sharing infrastructure with higher computing efficiency, lower cost and higher fle3xibility. But, still the security is being a hurdle that blocks the success of the cloud computing platform. Therefore, a novel Multi-tenant Decentralized Information Flow Control (MT-DIFC) model is introduced in this research work. The proposed system will encapsulate four types of entities: (1) The central authority (CA), (2) The encryption proxy (EP), (3) Cloud server CS and (4) Multi-tenant Cloud virtual machines. Our contribution resides within the encryption proxy (EP). Initially, the trust level of all the users within each of the cloud is computed using the proposed two-stage trust computational model, wherein the user is categorized bas primary and secondary users. The primary and secondary users vary based on the application and data owner's preference. Based on the computed trust level, the access privilege is provided to the cloud users. In EP, the cipher text information flow security strategy is implemented using the blowfish encryption model. For the data encryption as well as decryption, the key generation is the crucial as well as the challenging part. In this research work, a new optimal key generation is carried out within the blowfish encryption Algorithm. In the blowfish encryption Algorithm, both the data encryption as well as decryption is accomplishment using the newly proposed optimal key. The proposed optimal key has been selected using a new Self Improved Cat and Mouse Based Optimizer (SI-CMBO), which has been an advanced version of the standard Cat and Mouse Based Optimizer. The proposed model is validated in terms of encryption time, decryption time, KPA attacks as well.

Silica Aerogel: Synthesis and Applications

Gurav, Jyoti L.,Jung, In-Keun,Park, Hyung-Ho,Kang, Eul Son,Nadargi, Digambar Y. Hindawi Publishing Corporation 2010 Journal of nanomaterials Vol.2010 No.-

<P>Silica aerogels have drawn a lot of interest both in science and technology because of their low bulk density (up to 95% of their volume is air), hydrophobicity, low thermal conductivity, high surface area, and optical transparency. Aerogels are synthesized from molecular precursors by sol-gel processing. Special drying techniques must be applied to replace the pore liquid with air while maintaining the solid network. Supercritical drying is most common; however, recently developed methods allow removal of the liquid at atmospheric pressure after chemical modification of the inner surface of the gels, leaving only a porous silica network filled with air. Therefore, by considering the surprising properties of aerogels, the present review addresses synthesis of silica aerogels by the sol-gel method, as well as drying techniques and applications in current industrial development and scientific research.</P>

Periodontitis and Insulin Resistance: Casual or Causal Relationship?

Abhijit N. Gurav 대한당뇨병학회 2012 Diabetes and Metabolism Journal Vol.36 No.6

Insulin resistance (IR) is now considered as a chronic and low level inflammatory condition. It is closely related to altered glucose tolerance, hypertriglyceridemia, abdominal obesity, and coronary heart disease. IR is accompanied by the increase in the levels of inflammatory cytokines like interleukin-1 and 6, tumor necrosis factor-α. These inflammatory cytokines also play a crucial part in pathogenesis and progression of insulin resistance. Periodontitis is the commonest of oral diseases, affecting tooth investing tissues. Pro-inflammatory cytokines are released in the disease process of periodontitis. Periodontitis can be attributed with exacerbation of IR. Data in the literature supports a “two way relationship” between diabetes and periodontitis. Periodontitis is asymptomatic in the initial stages of disease process and it often escapes diagnosis. This review presents the blurred nexus between periodontitis and IR, underlining the pathophysiology of the insidious link. The knowledge of the association between periodontitis and IR can be valuable in planning effectual treatment modalities for subjects with altered glucose homeostasis and diabetics. Presently, the studies supporting this association are miniscule. Further studies are mandatory to substantiate the role of periodontitis in the deterioration of IR.

Preparation of Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> absorber layers by electrodeposition of Cu/Zn/Sn metallic layers

K. V. Gurav,S. W. Shin,S. M. Pawar,P. S. Patil,J. H. Moon,J. H. Kim 한국신재생에너지학회 2013 한국신재생에너지학회 학술대회논문집 Vol.2013 No.05

Whole-cell Immobilization of Engineered Escherichia coli JY001 with Barium-alginate for Itaconic Acid Production

문유미,Ranjit Gurav,김준영,홍윤기,Shashi Kant Bhatia,장혜림,홍주원,최태림,양수연,박형연,주황수,양영헌 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.4

Itaconic acid is an important organic acid and a major component of various polymers. It is used in resins, superabsorbent polymers, and substitutes for petrochemicalbased monomers such as acrylic and methacrylic acids. Itaconic acid is primarily produced by the fungus Aspergillus terreus, which yields a high titer with albeit long fermentation period and by-products. In our previous study, Escherichia coli JY001 was reported to produce itaconic acid using citric acid in whole-cell reaction resulting in higher itaconic acid productivity with less by-products formation. The present study aimed to increase whole-cell enzyme stability and reusability, via immobilization of E. coli JY001 using barium-alginate beads. We optimized the cations, temperature, pH, alginate, BaCl2 concentration, cell density per bead, and CTAB content to improve transfer rate of substrates and products. Under the optimized conditions, immobilized whole cells were stable for four repeated cycles of itaconic acid production. The present results would strengthen the basis for a continuous itaconic acid production.

Omega 3 fatty acids as a host modulator in chronic periodontitis patients: a randomised, double-blind, palcebo-controlled, clinical trial

Deore, Girish D.,Gurav, Abhijit N.,Patil, Rahul,Shete, Abhijeet R.,NaikTari, Ritam S.,Inamdar, Saurabh P. Korean Academy of Periodontology 2014 Journal of Periodontal & Implant Science Vol.44 No.1

Purpose: Periodontitis is an infectious disease caused predominantly by gram-negative anerobes. The host inflammatory response to these bacteria causes alveolar bone loss that is characterized as periodontitis. Omega-3 fatty acids (${\omega}$-3 FAs) have anti-inflammatory properties, thus have been used to treat some chronic inflammatory diseases such as cardiovascular disease and rheumatoid arthritis. We aimed to evaluate the effect of dietary supplementation with ${\omega}$-3 FAs as a host modulating agent in patients with chronic periodontitis. Methods: Sixty otherwise healthy subjects with moderate and severe chronic periodontitis were enrolled in our randomised, double-blind, placebo-controlled trial. The control group (CG, n=30) was treated with scaling and root planing (SRP) and given a placebo; the treatment group (TG, n=30) was treated with SRP and dietary supplementation of ${\omega}$-3 FAs (one 300 mg tablet daily for 12 weeks). Periodontal clinical parameters and serum C-reactive protein (CRP) levels were evaluated in all patients at baseline, a 6-week and 12-week period after treatment. Results: A significant reduction in the gingival index, sulcus bleeding index, pocket depth, and clinical attachment level was found in the TG compared to the CG at a 12-week period. However, no statistically significant changes in serum CRP levels were found. Conclusions: Our findings suggest that ${\omega}$-3 FAs can successfully reduce gingival inflammation, pocket depth, and attachment level gain. Dietary supplementation with ${\omega}$-3 FAs may have potential benefits as a host modulatory agent in the prevention and/or C management of chronic periodontitis.

Effect of synthetic and food waste-derived volatile fatty acids on lipid accumulation in <i>Rhodococcus</i> sp. YHY01 and the properties of produced biodiesel

Bhatia, Shashi Kant,Gurav, Ranjit,Choi, Tae-Rim,Jung, Hye-Rim,Yang, Soo-Yeon,Song, Hun-Suk,Kim, Yun-Gon,Yoon, Jeong-Jun,Yang, Yung-Hun Elsevier 2019 Energy conversion and management Vol.192 No.-

<P><B>Abstract</B></P> <P>Food waste-derived volatile fatty acids (VFAs) can act as a renewable feedstock for biodiesel production. In synthetic media, <I>Rhodococcus</I> sp. YHY01 was able to utilize various organic acids (acetate, butyrate, lactate, and propionate) as a carbon source. Butyrate was the optimal carbon source, having a minimum inhibitory effect on growth, and a maximum growth yield coefficient (Y<SUB>x/s</SUB> 0.288 g dcw/g butyrate) and fatty acid yield coefficient (Y<SUB>f/s</SUB> 0.206 g/g butyrate), compared to other organic acids (lactate, propionate, and acetate). Acetate, butyrate, and lactate mostly supported the production of fatty acids with an even number of carbons, whereas propionate enhanced the content of odd-numbered fatty acids. Response surface methodology (RSM) design study resulted in maximum biomass (2.8 g/L) and fatty acid yield (1.9 g/g) with acetate:butyrate:lactate (0.333:0.333:0.333) as a carbon source. Culture of <I>Rhodococcus</I> sp. YHY01 in media containing food waste-derived VFAs as the carbon source had a biomass (3.2 g dcw/L), fatty acid yield (2.2 g/L), and fatty acid accumulation (69% w/w) under nitrogen-limited condition. Biodiesel produced from food waste had an iodine value (IV, 37), cetane number (CN, 63), high heating value (HHV, 39), density (υ, 3.9), and viscosity (ρ, 0.868) that meet international standards.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Rhodococcus</I> sp. YHY01 can utilize volatile fatty acids as carbon source. </LI> <LI> Acetate, butyrate and lactate play role in even number fatty acids synthesis. </LI> <LI> Propionate directly involved in synthesis of odd carbon number fatty acids. </LI> <LI> Higher biomass and fatty acid yield coefficient obtained with butyrate. </LI> <LI> Food waste derived volatile fatty acids are a suitable feedstock for biodiesel production. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of scaling and root planing combined with systemic doxycycline therapy on glycemic control in diabetes mellitus subjects with chronic generalized periodontitis: a clinical study

Gaikwad, Subodh P.,Gurav, Abhijit N.,Shete, Abhijeet R.,Desarda, Hitesh M. Korean Academy of Periodontology 2013 Journal of Periodontal & Implant Science Vol.43 No.2

Purpose: The purpose of study was to compare glycemic control using glycated hemoglobin levels ($HbA_{1c}$) in diabetic patients with chronic generalized periodontitis (CGP) undergoing scaling and root planing (SRP) with and without systemic doxycycline. Methods: Fifty subjects with type 2 diabetes mellitus ($T_2DM$) and CGP receiving antidiabetic therapy were selected for study. The selected subjects were randomly assigned to two groups (test group [TG] and control group [CG]) comprising 25 patients each. The TG received SRP followed by systemic doxycycline. The CG received treatment with SRP only. The periodontal parameters were recorded at baseline (day zero), and every 1 month for 4 months and included probing depth, clinical attachment level, plaque index, gingival index, and $HbA_{1c}$ level were recorded at baseline (day zero) and at the end of 4 months. Results: A statistically significant effect was demonstrated for the periodontal parameters for both the TG and CG. $HbA_{1c}$ values did not show a statistically significant difference in the treatment group as compared to the CG. Conclusions: The authors concluded that nonsurgical periodontal therapy improved glycemic control in patients with $T_2DM$ in both groups, but no statistical difference was observed with adjunctive systemic doxycycline therapy. A further study with a larger sample size is required.