188 results on '"Maiti, Subhabrata"'
Search Results
152. GNP confinement at the interface of cationic reverse micelles: influence in improving the lipase activity
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Ghosh, Moumita, primary, Maiti, Subhabrata, additional, Brahmachari, Sayanti, additional, and Das, Prasanta Kumar, additional
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- 2012
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153. Unmodified “GNP-Oligonucleotide” Nanobiohybrids: A Simple Route for Emission Enhancement of DNA Intercalators
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Maiti, Subhabrata, primary, Dutta, Sounak, additional, and Das, Prasanta Kumar, additional
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- 2011
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154. In situ synthesized Ag nanoparticle in self-assemblies of amino acid based amphiphilic hydrogelators: development of antibacterial soft nanocomposites
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Shome, Anshupriya, primary, Dutta, Sounak, additional, Maiti, Subhabrata, additional, and Das, Prasanta Kumar, additional
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- 2011
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155. Gold nanorod in reverse micelles: a fitting fusion to catapult lipase activity
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Maiti, Subhabrata, primary, Ghosh, Moumita, additional, and Das, Prasanta Kumar, additional
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- 2011
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156. Refining hydrogelator design: soft materials with improved gelation ability, biocompatibility and matrix for in situ synthesis of specific shaped GNP
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Das, Dibyendu, primary, Maiti, Subhabrata, additional, Brahmachari, Sayanti, additional, and Das, Prasanta Kumar, additional
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- 2011
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157. Influence of Gold Nanoparticles of Varying Size in Improving the Lipase Activity within Cationic Reverse Micelles
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Maiti, Subhabrata, primary, Das, Dibyendu, additional, Shome, Anshupriya, additional, and Das, Prasanta Kumar, additional
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- 2010
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158. Multivalent Interactions Regulate Signal Transduction in a Self-Assembled Hg2+ Sensor.
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Maiti, Subhabrata, Pezzato, Cristian, Martin, Sergio Garcia, and Prins, Leonard J.
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MULTIVALENT molecules , *CELLULAR signal transduction , *MOLECULAR self-assembly , *MERCURY , *GOLD nanoparticles , *LIGANDS (Chemistry) , *QUENCHING (Chemistry) , *FLUORESCENCE - Abstract
A self-assembled sensing system able to detect Hg2+ at low nanomolar concentrations is reported that operates through a signal transduction pathway involving multivalent interactions. The analyte causes dimerization of low-affinity ligands, resulting in a complex with a high affinity for a multivalent monolayer-protected gold nanoparticle (AuNP). This complex displaces a quenched fluorescent reporter from the AuNP, resulting in a turn ON of fluorescence. It is shown that the strength of the output signal can be regulated by tuning the multivalent interactions between the complex and the NP. Finally, it is shown that multivalent interactions drive the self-selection of a high-affinity complex from a mixture of low-affinity ligands. [ABSTRACT FROM AUTHOR]
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- 2014
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159. Probing Enzyme Location in Water-in-Oil MicroemulsionUsing Enzyme–Carbon Dot Conjugates.
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Das, Krishnendu, Maiti, Subhabrata, and Das, Prasanta Kumar
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WATER chemistry , *FATS & oils , *MICROEMULSIONS , *ENZYMES , *CARBON , *AQUEOUS solutions , *CHROMOBACTERIUM - Abstract
Thisarticle delineates the formation and characterization of differentenzyme–carbon dot conjugates in aqueous medium (pH = 7.0).We used soybean peroxidase (SBP), Chromobacterium viscosum(CV) lipase, trypsin, and cytochrome c(cyt c) for the formation of conjugate either with cationic carbondot (CCD) or anionic carbon dot (ACD) depending on the overall chargeof the protein at pH 7.0. These nanobioconjugates were used to probethe location of enzymes in water-in-oil (w/o) microemulsion. The sizeof the synthesized water-soluble carbon dots were of 2–3 nmwith distinctive emission property. The formation of enzyme/protein–carbondot conjugates in aqueous buffer was confirmed via fluorescence spectroscopyand zeta potential measurement, and the structural alteration of enzyme/proteinwas monitored by circular dichroism spectroscopy. Biocatalytic activitiesof protein/enzymes in conjugation with carbon dots were found to bedecreased in aqueous phosphate buffer (pH 7.0, 25 mM). Interestingly,the catalytic activity of the nanobioconjugates of SBP, CV lipase,and cyt cdid not reduce in cetyltrimethylammoniumbromide (CTAB)-based reverse micelle. It indicates different localizationof carbon dots and the enzymes inside the reverse micelle. The hydrophiliccarbon dots always preferred to be located in the water pool of reversemicelle, and thus, enzyme must be located away from the water pool,which is the interface. However, in case of trypsin–carbondot conjugate, the enzyme activity notably decreased in reverse micellein the presence of carbon dot in a similar way that was observed inwater. This implies that trypsin and carbon dots both must be locatedat the same place, which is the water pool of reverse micelle. Carbondot induced deactivation was not observed for those enzymes whichstay away from the water pool and localized at the interfacial domainwhile deactivation is observed for those enzymes which reside at thewater pool. Thus, the location of enzymes in the microdomain of w/omicroemulsion can be predicted by comparing the activity profile ofenzyme–carbon dot conjugate in water and w/o microemulsion. [ABSTRACT FROM AUTHOR]
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- 2014
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160. In situ synthesized Agnanoparticle in self-assemblies of amino acid based amphiphilic hydrogelators: development of antibacterial soft nanocomposites.
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Shome, Anshupriya, Dutta, Sounak, Maiti, Subhabrata, and Das, Prasanta Kumar
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- 2011
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161. Computer-aided prosthetic rehabilitation of a resected maxilla after mucormycosis using a quad zygomatic implant protocol with digital planning.
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Koppaka R, Maiti S, Ahmed N, Abhinav RP, and Arun M
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The rehabilitation of patient function and esthetics is essential from a social and psychological point of view. After a maxillary resection, the supporting structures that help provide retention or stability to a removable prosthesis are lacking. An effective, functional, straightforward, comfortable, and esthetic prosthetic rehabilitation of a patient with a resected maxilla using a digital workflow is presented. The rehabilitation was done using a computer-aided design and computer-aided manufactured bar and clip-supported overdenture prosthesis over quad zygomatic implants., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)
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- 2024
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162. Comparative Evaluation of Microbial Adhesion on Provisional Crowns Fabricated With Milled Polymethyl Methacrylate (PMMA) and Conventional Acrylic Resin: A Prospective Clinical Trial.
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Singh P, Shenoy A, Nallaswamy D, and Maiti S
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Introduction Provisional prosthetic restorations play a crucial role in dentistry by protecting dentinal tubules, offering thermal insulation, and ensuring a precise fit during dental treatments. Computer-aided design and computer-aided manufacturing (CAD/CAM) have improved polymethyl methacrylate (PMMA), enhancing its mechanical properties such as hardness and resistance compared to traditional methods. However, bacterial accumulation remains a challenge due to inherent surface roughness. This study aims to assess and compare Streptococcus mutans adhesion on milled PMMA and conventional self-cure acrylic resin, providing insights into their microbial interaction dynamics. Materials and methods This study was a prospective trial approved by the Institutional Human Ethical Committee (SRB-IHEC) (registration number: IHEC/SDC/PROSTHO-2104/24/045) and registered in the Clinical Trial Registry, India (registration number: CTRI/2024/05/068196). The study involved 20 patients requiring single crowns in the right and left molar regions. Two groups were established: Group I (the milled PMMA group) and Group II (the conventional PMMA group). Criteria for participant selection and exclusion were set. A total of 120 swab samples from the buccal mucosa and tooth surfaces were collected before tooth preparation (the baseline) at one week and three weeks. Culture for S. mutans was done, and colony-forming units were counted. Data analysis was carried out using IBM SPSS Statistics for Windows, Version 26 (Released 2019; IBM Corp., Armonk, New York, United States). An independent sample t-test was employed to compare the two materials for crowns. To analyze changes over time within each group, a repeated-measures analysis of variance (ANOVA) was conducted. When the ANOVA test indicated significance, Tukey's post-hoc test was utilized for pairwise mean comparison. The level of significance was set at P < 0.05. Results The mean colony-forming units (CFU) counts for the milled PMMA group were 4.46 ± 0.167 CFU at baseline, 4.163 ± 0.058 CFU at one week, and 3.87 ± 0.19 CFU at three weeks. The mean CFU counts for the conventional PMMA group were 4.41 ± 0.13 CFU at baseline, 4.29 ± 0.114 CFU at one week, and 4.16 ± 0.108 CFU at three weeks. At baseline (before cementation), there was no difference between milled PMMA and conventional PMMA (P = 0.578). After one week, a significant difference between milled PMMA and conventional PMMA was observed (P < 0.005). After three weeks, a significant difference between milled PMMA and conventional PMMA persisted (P < 0.005). Conclusion There was a significant reduction in microbial adhesion in both the milled and conventional PMMA groups. However, milled PMMA demonstrated a greater decrease in microbial adhesion as compared to conventional PMMA., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Human Ethical Committee (SRB-IHEC) issued approval IHEC/SDC/PROSTHO-2104/24/045. The trial was registered in the Clinical Trial Registry, India (registration number CTRI/2024/05/068196), registration date: 31/05/2024. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Singh et al.)
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- 2024
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163. Multifaceted Enhancement of L-Leucine-Enriched Ovine Bone Graft: Physicochemical Characteristics and Osteogenic Potential for Improved Guided Bone Regeneration.
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Koppaka R, Shah KK, and Maiti S
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Introduction Small compounds like L-leucine can boost bone regrowth by blocking certain effects, sparking cell reactions through signaling sequences. This research explored how combining L-leucine with hyaluronic acid on the developed novel graft material affects the bone's ability to conduct bone-building processes. Material and methods This study was designed as an in-vitro experiment, where a novel bone graft was formulated by integrating L-leucine with hyaluronic acid and incorporated into a hydroxyapatite-based ovine bone graft material. The sintering procedure was modified to include the amino acid L-arginine. Comprehensive examinations were executed using methodologies such as scanning electron microscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy (FTIR), MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and bone formation assay. These analyses were juxtaposed with the characteristics of the commercially accessible unaltered Bio-Oss, focusing on their physicochemical properties. The properties were compared with a commercially available bone graft material. Results The sintered hydroxyapatite/L-leucine graft displayed an interconnected pore structure, indicating that higher sintering and consolidation affected hydroxyapatite, as observed through scanning electron microscopy. X-ray diffraction (XRD) analysis confirmed hydroxyapatite in the sintered ovine bone samples, affirming their suitability for various biomedical applications. In the bone formation assay, optical density (OD) values were 61% for the hydroxyapatite/L-arginine graft, 58% for the Bio-Oss group, and 51% for the control group. The MTT assay, which assesses cell viability and metabolic activity, demonstrated biocompatibility and cell growth for all samples at 24 hours. Conclusion The research noted beneficial outcomes by incorporating L-leucine into the novel bone graft material with hyaluronic acid for bone grafting, demonstrating enhanced compatibility with existing bone tissue. However, the specific advantages of this combined approach are not fully known. It is essential to conduct more studies to uncover how this synergy works, assess its prolonged impacts, carry out clinical tests, and enhance the effectiveness of this blend for practical applications in bone graft surgeries., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: Scientific Review Board - (SRB/SDC/PROSTHO-20/22/TH-126) Samples were, however, obtained from the cortical hind limb femur goat bones collected from the local slaughterhouse located in Chennai, Tamil Nadu. Issued protocol number SRB/SDC/PROSTHO-20/22/TH-126. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Koppaka et al.)
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- 2024
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164. Green Synthesis and Investigation of Antimicrobial Activity and Compressive Resilience of Glass Ionomer Cement Modified With Zirconia Nanoparticles: An In Vitro Study.
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Jain K, Paulraj J, Maiti S, and Shanmugam R
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Background Glass ionomer cement (GIC) serves as a crucial biomaterial in dental restoration, offering applications in filling, lining, and adhesive procedures. Nevertheless, its mechanical properties often fall short, particularly in regions subjected to considerable stress. To address this issue, zirconia nanoparticles are incorporated at specific levels. Aim To assess the antimicrobial efficacy and compressive resilience of GIC modified with zirconia nanoparticles synthesized through green synthesis methods. Material and methods Zirconia nanoparticles were synthesized via a green method utilizing aloe vera extract in solvent form. These nanoparticles were then mixed into GIC at different concentration levels. Group I incorporated zirconia nanoparticles at a concentration of 3%, Group II at 5%, and Group III at 10%, while Group IV was the control, consisting of traditional GIC. Following that, samples were prepared and underwent characterization through various analytical techniques. The ability to inhibit microbial growth and the compressive resilience of the groups were examined. Microbial inhibition against the bacterial strains was assessed through minimum inhibitory concentration (MIC), and the ability to withstand compression was gauged by measuring the maximum force the specimen could endure before fracturing. Data underwent analysis with Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 24.0, Armonk, NY). Repeated measures of analysis of variance (ANOVA) were utilized to gauge average MIC values and compressive strength. Following this, Tukey's post hoc test was employed for pairwise comparisons. Results The findings indicated, incorporating zirconia nanoparticles into GIC led to an improvement in its antimicrobial effectiveness, with a noticeable enhancement observed as the weight percent (% wt) of the additive increased. This improvement was notably noticeable in its effectiveness against Streptococcus mutans and Lactobacillus , exceeding that of the control with a noteworthy distinction. Furthermore, there were significant enhancements in compressive strength, in Group I (180.48 ± 1.02), Group II (191.25 ± 0.52), and Group III (197.52 ± 0.75), compared to Group IV (167.22 ± 1.235), with significant disparities (p < 0.05). Conclusion The research illustrates that introducing green-synthesized zirconia nanoparticles into GIC leads to heightened bactericidal potency and compressive resilience when contrasted with the control group (Group IV). Notably, the highest concentration of 10% demonstrated the most favourable antimicrobial attributes alongside enhanced strength. Consequently, integrating green-synthesized zirconia nanoparticles into GIC holds potential as a proficient material. In future studies, there should be an exploration of molecular chemistry and bonding mechanisms to enhance our comprehension of its capabilities., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Jain et al.)
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- 2024
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165. Green Synthesis, Characterization, and Evaluation of the Antimicrobial Properties and Compressive Strength of Hydroxyapatite Nanoparticle-Incorporated Glass Ionomer Cement.
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Ilancheran P, Paulraj J, Maiti S, and Shanmugam R
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Background Glass ionomer cement (GIC) plays a vital role in dental restorative procedures, serving purposes such as filling, luting, and adhesion. However, its inadequate mechanical properties pose challenges, especially in areas experiencing significant stress. To overcome this limitation, nanohydroxyapatite (nHA), known for its bioactive phosphate content, is added to the GIC at specific concentrations to improve its properties. Aim We aim to evaluate the antimicrobial property and compressive strength of green-mediated nHA-incorporated GIC. Material and methods Green synthesis of hydroxyapatite nanoparticles was prepared using Moringa oleifera extract in a solvent form and eggshell waste served as the calcium source. These nHA powders were then integrated into the GIC at varying concentrations (3%, 5%, and 10%) designated as Group I, Group II, and Group III, respectively, while Group IV (control) consisted of conventional GIC. Specimens were fabricated and subjected to chemical structure analysis through Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). The antimicrobial activity and compressive strength of all groups were investigated. The antimicrobial activity against Streptococcus mutans and Lactobacillus was evaluated through the minimum inhibitory concentration (MIC) test, while compressive strength was evaluated by measuring the maximum force endured by the specimen before fracturing. Data analysis utilized IBM SPSS Statistics software, employing repeated measures ANOVA to determine mean MIC values and compressive strength, with Tukey's posthoc test for pairwise comparisons. Results The results of the study showed that the antimicrobial efficacy of nHA GIC improved with increasing weight percent (% wt) of the additive, exhibiting significantly enhanced activity against Streptococcus mutans and Lactobacillus compared to the control group (Group IV) with statistical significance (p < 0.05). Moreover, the compressive strength exhibited notable enhancements in the modified groups, including Group I (172.55 ± 0.76), Group II (178.16 ± 0.760), and Group III (182.45 ± 0.950), when compared to the control (162.46 ± 1.606), with statistically significant differences (p < 0.05). Conclusion The study demonstrates that the incorporation of green-mediated nHA-containing GIC results in superior antimicrobial efficacy and compressive strength compared to the control group (Group IV). In particular, the highest concentration of nHA-modified GIC (10%) exhibited the most favorable antimicrobial properties along with increased strength. Therefore, utilizing green-mediated nHA in the GIC shows promise as an effective restorative material. Future investigations should delve into the molecular chemistry and bonding mechanisms to further explore its potential., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ilancheran et al.)
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- 2024
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166. A Comparative In Vitro Analysis of Antimicrobial Effectiveness and Compressive Strength of Ginger and Clove-Modified Glass Ionomer Cement.
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Paulraj J, Pushparathna B, Maiti S, Sharma N, and Shanmugam R
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Background Glass ionomer cement (GIC) is widely recognized for its self-adhesive characteristics and biocompatibility, making it commonly used as a restorative material. However, challenges related to limited antibacterial effectiveness and relatively low mechanical properties have hindered its widespread clinical use. Clove and ginger are recognized for their potent antimicrobial activity against numerous pathogenic microorganisms. The present study aims to enhance the clinical applicability of GIC by modifying it with clove and ginger extract. Aim The objective of the study is to assess the antimicrobial effectiveness and compressive strength of GIC modified with ginger and clove extract. Materials and methods Ginger and clove extracts were prepared and incorporated into conventional GIC at three concentrations for each, creating ginger-modified GIC groups (Group A, Group B, and Group C) and clove-modified GIC groups (Group D, Group E, and Group F), with Group G as the control (conventional GIC without modification). The antimicrobial assessment was conducted on disc-shaped GIC specimens (3.0 mm height x 6.0 mm diameter) prepared using molds. Bacterial strains were used to evaluate antimicrobial properties, with minimum inhibitory concentration (MIC) assays conducted at intervals of one to four hours for both modified and unmodified groups. Compressive strength specimens were prepared using cylindrical molds (6.0 mm height × 4.0 mm diameter), according to the ISO (International Organization for Standardization) guidelines. The evaluation was conducted using a Zwick universal testing machine (ElectroPuls® E3000, Instron, Bangalore, India), with the highest force at the point of specimen fracture recorded to determine compressive strength. Statistical analysis was conducted utilizing a one-way analysis of variance (ANOVA) alongside Tukey's post hoc test, with a significance threshold set at p < 0.01. Results The antimicrobial effectiveness of clove and ginger-modified GIC was assessed through a MIC assay, revealing a statistically significant improvement in antimicrobial potency against Streptococcus mutans and Lactobacillus within the modified groups compared to the control group (p < 0.01). Increased extract concentration correlated with enhanced antimicrobial activity. Clove-modified GIC exhibited superior antimicrobial efficacy compared to ginger extract. Compressive strength was higher in clove-modified GIC groups (p < 0.01), with Group F showing a maximum value of 175.88 MPa, while other modified groups demonstrated similar results to the control, with a value of 166.81 MPa (p > 0.01). Conclusion The study concludes that both clove-modified GIC and ginger-modified GIC exhibited antimicrobial activity against Streptococcus mutans and Lactobacillus species. The antimicrobial activity was notably higher in clove-modified GIC compared to ginger-modified GIC. Additionally, the compressive strength of clove-modified GIC surpassed all other groups. Thus, clove-modified GIC emerges as a promising restorative material for addressing recurrent caries. Future investigation is necessary to assess the long-term durability of the material., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Paulraj et al.)
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- 2024
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167. A Comparative In Vitro Analysis of Antimicrobial Effectiveness and Compressive Resilience in Chirata and Terminalia arjuna Modified Glass Ionomer Cement.
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Devi K, Paulraj J, George RS, Shanmugam R, and Maiti S
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Background: Glass ionomer cements are commonly utilized in dental restorations due to their biocompatibility, strong chemical bond with dental tissues, and ability to resist tooth decay. However, their effectiveness can be compromised by the presence of persistent cavity-causing microorganisms. Therefore, it is essential to consider incorporating antibacterial agents into these restorative materials. Swertia chirayita (S. chirayita) and Terminalia arjuna (T. arjuna) are well-known for their rich composition of phytochemicals that can potentially inhibit the growth of bacteria. Hence, the current research is focused on modifying glass ionomer cement with Chirayita and T. arjuna extracts to enhance its antibacterial properties., Aim: This research aims to determine the antimicrobial efficacy and compressive strength of glass ionomer cement modified with Chirayita and T. arjuna extracts., Methodology: Plant extracts were prepared from both Chirayita and T. arjuna. The powder and liquid components of conventional glass ionomer cement (GIC) were mixed, followed by adding these extracts at three different concentrations. To assess antimicrobial properties, typical strains of Streptococcus mutans and Lactobacillus were employed to test both the modified GIC and unmodified GIC (used as a control). For Chirayita and T. arjuna-modified GIC, minimum inhibitory concentration (MIC) assays were conducted at three different concentrations. MIC was assessed at various time intervals ranging from 1 to 4 hours for modified and unmodified groups. Moreover, compressive strength was measured using cylindrical molds. The highest force exerted at the point of specimen fracture was recorded to calculate the compressive strength values in megapascal (MPa)., Results: The antimicrobial efficiency of Chirata and T. arjuna-modified GIC was evaluated using a MIC assay, indicating a statistically significant enhancement in antimicrobial potency against S. mutans and Lactobacillus within the modified groups in contrast to the control group (p<0.05). However, there were no notable changes in compressive strength when comparing the control group to the modified groups (p>0.05)., Conclusion: The antimicrobial effectiveness against S. mutans was observed to be greater in both T. arjuna and Chirayita-modified GIC. In the case of Lactobacillus, Chirayita-modified GIC exhibited more pronounced antimicrobial properties compared to T. arjuna. Importantly, both extracts did not alter the compressive strength of Conventional (unmodified) GIC. Hence, Chirayita-modified GIC appears to be a promising restorative material for combatting recurrent caries. Additional investigation is required to assess the material's stability over an extended period., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Devi et al.)
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- 2024
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168. Effectiveness of Photobiomodulation With Low-Level Laser Therapy on the Implant Stability Quotient at Different Time Intervals: A Randomized Clinical Trial.
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Shenoy A, Ganapathy D, and Maiti S
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Background Photobiomodulation techniques, particularly low-level laser therapy (LLLT), have gained traction due to their ability to accelerate osseointegration by stimulating cellular metabolism and promoting tissue healing. This study explores the effectiveness of LLLT around dental implants at various intervals after placement. Using resonance frequency analysis (RFA), the implant stability quotient (ISQ) was measured to assess implant stability. Methodology This split-mouth, randomized, single-blinded clinical trial included 20 participants undergoing dental implant placement. The test group received LLLT while the control group had no laser treatment. Implant stability was assessed using RFA at one, two, four, and twelve weeks post-implant placement. Statistical analysis involved descriptive statistics, repeated-measures analysis of variance (ANOVA), and t-tests. Results The repeated-measures ANOVA analysis showed significant differences in the ISQ values between the LLLT group and the control group at two weeks and three months post-implant placement. The LLLT group exhibited higher ISQ values, indicating greater implant stability and improved osseointegration compared to the control group. These findings suggest the potential benefits of LLLT in enhancing dental implant outcomes. Conclusions LLLT shows promise in improving dental implant outcomes, with enhanced stability and osseointegration. Further research is needed to validate these results and integrate LLLT into routine dental implant procedures., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Shenoy et al.)
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- 2024
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169. Benchmarking Cationic Monolayer Protected Nanoparticles and Micelles for Phosphate-Mediated and Nucleotide-Selective Proton Transfer Catalysis.
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Mahato RR, Juneja S, and Maiti S
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Both micelles and self-assembled monolayer (SAM)-protected nanoparticles are capable of efficiently hosting water-immiscible substrates to carry out organic reactions in aqueous media. Herein, we have analyzed the different catalytic effect of SAM-protected cationic nanoparticles and cationic surfactants of varying chain length towards base-catalyzed proton transfer mediated ring-opening reaction of 5-nitrobenzisoxazole (NBI) (also known as Kemp Elimination (KE) reaction). We use inorganic phosphate ion or different nucleotide (phosphate-ligated different nucleoside) as base to promote the reaction on micellar or nanoparticle interface. We find almost 2-3 orders of magnitude higher concentration of surfactants of comparable hydrophobicity required to reach the similar activity which attained by low cationic head group concentration bound on nanoparticle. Additionally, at low concentration of nanoparticle-bound surfactant or with high surfactant in micellar form, nucleotide-selectivity has been observed in activating KE reaction unlike free surfactant at low concentration. Finally, we showed enzyme-mediated nucleotide hydrolysis to generate phosphate ion which in situ upregulate the KE activity much more in GNP-based system compared to CTAB. Notably, we show a reasonable superiority of SAM-protected nanoparticles in activating chemical reaction in micromolar concentration of headgroup which certainly boost up application of SAM-based nanoparticles not only for selective recognition but also as eco-friendly catalyst., (© 2023 Wiley-VCH GmbH.)
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- 2023
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170. An in vitro comparison of the marginal fit of provisional crowns using the virtual tooth preparation workflow against the traditional technique.
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Shenoy A, Maiti S, Nallaswamy D, and Keskar V
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- Humans, Workflow, Dental Prosthesis Design methods, Dental Marginal Adaptation, India, Crowns, Computer-Aided Design
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Aim: This study investigates the effectiveness of an innovative virtual tooth preparation workflow for the fabrication of dental crowns using cone-beam computed tomography (CBCT) and intraoral scanners (IOSs) with conventional workflow using extraoral/laboratory scanners., Settings and Design: This in vitro experimental study was conducted in the laboratory of a university in Chennai, India. The dental laboratory and research facilities at the institution were utilized for the fabrication of the temporary crowns and the data acquisition process., Materials and Methods: Institutional approval was obtained from the university. It was basically a comparison between the virtual prep technique using CBCT and IOS and the conventional digital technique using extra oral scanners (EOS) for temporary crown fabrication. The sample size was estimated using an effect size of 1.5004, assuming a normal distribution, a significance level of 0.05, and a power of 0.95 in G power software. Based on this calculation, an extracted second lower molar was used to fabricate 10 samples in each group. The samples were divided into three groups: the CBCT (Group 1), the IOS (Group 2), and laboratory scanner (Group 3 as control) groups. The vertical marginal gap of all the surfaces of the crown was evaluated using a scanning electron microscope., Statistical Analysis Used: Data were analyzed using one-way ANOVA using the SPSS software version 26.0, IBM, Armonk, NY, USA., Results: Acceptable marginal discrepancy values were obtained in all three groups. There was no significant difference in the marginal discrepancy recorded (P = 0.113)., Conclusion: Virtual tooth preparation using CBCT and IOSs can be used as an alternative to the conventional workflow for provisional crown and bridge fabrication.
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- 2023
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171. Evaluation of Peri-Implant Crestal Bone Loss with Different Implant Systems, Primary Stability, Bone Density and Soft Tissue Thickness: A Retrospective Study.
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Shenoy A, Rohinikumar S, Maiti S, Sivaswamy V, and Rajaraman V
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Aim: The purpose of this retrospective study was to compare, among various implant systems, the influence of primary stability and the bone density and soft tissue biotype of the patient on the amount of peri-implant crestal bone loss after 1 year using radiography., Materials and Methods: Included in this retrospective study were patient records of 3583 implant placements utilized from an online dental information archiving software (DIAS). Clinical and radiographic assessments were conducted concurrently with implant placement (baseline) and 1 year post surgery. Statistical analysis was done to examine the mean marginal bone loss significance in the three different implant systems groups (group I: Straumann Roxolid SLAc-tive, group II: Nobel Biocare CC, group III: Straumann SLA), different primary stability values, different bone density. and soft tissue biotype at the time of implant placement., Results: A significant difference was observed in the crestal bone loss with different implant systems used. Group I showed significantly lesser amounts of crestal bone loss when compared to groups II and III. However, the differences in the bone density, ISQ values, and the soft tissue biotype did not exhibit a statistically significant difference in the amount of crestal bone loss., Conclusion: Significant MBL preservation for implants with Straumann SLActive when compared to Nobel Biocare CC and Straumann SLA implants. No significant changes were observed with respect to primary stability, bone density, and soft tissue thickness and no correlation among early crestal bone loss and IT, ISQ at surgery, and ISQ at reopening was observed. Straumann Roxolid SLActive implants showed less crestal bone loss probably owing to its hydrophilic surface modification. However, more studies need to be done to evaluate the same.
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- 2023
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172. Knowledge, Attitude, and Perception Regarding the Financial Aspects of Prosthetic Rehabilitation Using Dental Implants: A Double-Questionnaire-Based Study.
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Shenoy A, Ganapathy DM, Maiti S, and Sivaswamy V
- Subjects
- Humans, Health Knowledge, Attitudes, Practice, Surveys and Questionnaires, Perception, Dental Implants
- Abstract
To assess up to date patient and doctor perceived costs of dental implant surgery among the Indian population as there is a lack of information regarding patients' awareness of dental implants. Two online questionnaire forms were sent over the internet to the Indian population and the Indian dentists and dental students regarding the knowledge, attitude and perception regarding the dental implant surgery for rehabilitation of a single missing tooth. Statistical analysis was then carried out using SPSS software version 23.0. Thirty-eight percent (P < 0.05) of the participants questioned the thought that implants require the same care as fixed prostheses, and thought it was a better option due to a major percent expecting an additional payment > 10,000 indian rupees. The expectations that patients have for an implant-supported set are high in contrast to their willingness to make additional payments. There are still misconceptions regarding costs, and these must be resolved individually in practice.
- Published
- 2023
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173. Quality of life post oral rehabilitation with complete short arch among South Indian patients.
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Agarwal V, Ashok V, and Maiti S
- Abstract
Oral rehabilitation is essential in patients having multiple missing teeth, to restore esthetics and function. However replacement of complete dentition may not be possible in high risk patients or patients of low income group. The concept of SDA can be utilized in such patients to increase affordability and avoid over restoring. The aim of this study was to understand the prevalence of the requirement of oral rehabilitation according to age and gender of the individual as well as to compare the quality of life of patients rehabilitated with complete and short dental arches. Case sheets of around 28,000 patients were reviewed from March 2019 to June 2020 out of which 113 patients were undergoing oral rehabilitation. To eliminate bias all patients affected by the disease were included in the study. Epidemiological data of the patient along with their ongoing treatment was collected and tabulated in MS Excel sheet. Amongst the patients 36 patients were selected using simple stratified sampling and patients were asked to report their quality of life on a VAS scale using a quality of life questionnaire. The data was then analyzed using IBM SPSS software version 23. The prevalence of oral rehabilitation in males was 53.98% while in females it was 48.02%. Age group of 41-60 years was found to be most commonly undergoing oral rehabilitation. The most common extent of rehabilitation was 2nd molar - 2nd molar, around 23% patients underwent rehabilitation from 1st molar-1st molar and around 10% patients underwent rehabilitation from 2nd premolar-2nd premolar. Patient satisfaction was greatest in patients with complete arch restoration when compared to short dental arch restoration. Amongst SDA restoration patients rehabilitated till the first molar had greater satisfaction than patients rehabilitated till second premolar. With increase in lifespan the need for oral rehabilitation has increased, however it is not always possible or advised to restore the complete dentition of an individual. The present study helps us understand the prevalence of oral rehabilitation according to the gender and age of the patients as well as use of newer concepts such as SDA in the management of high risk patients. Within the limitations of the present study patient satisfaction was greater in complete arch restoration compared to SDA. Thus it is important to understand the requirements of the patient and rehabilitate accordingly, so as to provide the patient with the best esthetics and function possible., Competing Interests: There were no conflicts of interest present, (© 2022 Biomedical Informatics.)
- Published
- 2022
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174. Inhibitory effect of nucleotides on acetylcholine esterase activity and its microflow-based actuation in blood plasma.
- Author
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Deshwal A, Gill AK, Nain S, Patra D, and Maiti S
- Subjects
- Acetylcholinesterase, Cholinesterase Inhibitors, Lab-On-A-Chip Devices, Plasma, Acetylcholine, Nucleotides
- Abstract
The inhibitory effect of nucleotides on the catalytic activity of acetylcholine esterase (AChE) was rationalized and a similar inhibition trend was observed when analyzing the macroscopic fluid flow generated by surface immobilized AChE. Additionally, the demonstration of enzymatic micropumping by showing adenine-nucleotide responsive AChE actuated fluid flow from blood plasma paved the way for designing future lab-on-a-chip devices in complex biological environments with potential clinical applications.
- Published
- 2022
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175. Evaluation of Microbial Leakage at Implant Abutment Interfact for Different Implant Systems: An In Vitro Study.
- Author
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Kushali R, Maiti S, Girija SAS, and Jessy P
- Subjects
- Dental Abutments, Humans, Dental Implants adverse effects, Prostheses and Implants
- Abstract
Two-stage implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues. These gaps between the components are inevitable, and their clinical significance has so far been mostly neglected by both manufacturers and clinicians. This study is thus intended to evaluate microbial leakage at implant abutment interface in different implant systems. Four different systems, the Nobel tri-channel, the Nobel conical, the Equinox, and the Straumann, were used for this study. One microliter of a fresh broth suspension of Streptococcus mutans was added to the implant fixture (implant body). The implant was immersed in fresh heart brain infusion and was incubated at 37° for 48 hours. After incubation, 10 μL of the broth was made as lawn culture on sterile agar and the colonies were counted and recorded as colony-forming units per milliliter. Statistical tests were carried out on SPSS software and tests included analysis of variance (ANOVA) and P value was derived using Tukey's honestly significant difference post hoc test. After incubation, results were analyzed by evaluating the microbial leakage from each sample and it was observed that Nobel tri-channel had the least amount of microbial leakage and Equinox had maximum microbial leakage. The difference among all implant systems was statistically significant P < 0.05. The study concluded that least micro-leakage was found in the Nobel tri-channel whereas maximum microbial leakage was present in Equinox and Straumann.
- Published
- 2022
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176. An Analysis of Implant Prosthesis and Its Dynamic Occlusal Contacts.
- Author
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Venugopalan S, R S, N T, and Maiti S
- Subjects
- Animals, Humans, Crowns, Prostheses and Implants, Deer
- Abstract
The prosthetic replacement is achieved for the functional aspect of the stomatognathic system. Achieving prosthetic occlusion is challenging and has an occlusal concept of its own when the type of prosthesis varies. The implant occlusion differs for its load transfer concept and longevity. The study was employed to assess the dynamic occlusal contact in implant occlusion through digital means. The study was carried out on implant prosthesis and its dynamic parameters were evaluated using T-Scan Novus (BioResearch, Inc., Brown Deer, WI, USA) in a university hospital setting after collecting 35 patients. Mandibular arch prosthesis tends to swing from high intensity to low or no contacts frequently and when the percentage of implant crown contact at 10% is present there is more of implant protected occlusion achieved. Use of T-Scan Novus can reveal more occlusal details in functional form which can help in achieving new treatment goals.
- Published
- 2022
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177. Dentists' Preference toward Fixed Versus Removable Implant Prosthesis on Edentulous Jaws to Improve Quality of Life.
- Author
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Agarwal S, Ashok V, Maiti S, and Agarwal V
- Subjects
- Adult, Aged, Female, Humans, Cross-Sectional Studies, Dentists, Denture, Overlay, Quality of Life, Dental Implants, Jaw, Edentulous
- Abstract
Implants that can be used in the prosthetic rehabilitation of full and partial edentulous patients are now frequently used due to advances in dentistry. The aim of the study is to find the prevalence of implant supported fixed vs. removable prosthesis and associated quality of life evaluation. A cross-sectional, descriptive study was conducted in an institution, on randomly selected individuals. The study group consisted of adult patients who attended the outpatient Department of Prosthodontics from June 2019-March 2020. Eighty-six thousand (86,000) case sheets were evaluated and Chi-square test, independent t-test and frequency analysis were used to explore the relationship between two variables. Out of the patients, 76.5% preferred fixed prosthesis while 23.5% chose removable prosthesis. Females preferred fixed prosthesis over removable. The young-old age group had more removable prosthesis compared to the middle- and elderly age group. Patients with implant supported fixed dental prosthesis had a better quality of life compared with patients with implant supported overdentures. Esthetic and functional rehabilitation is a preferred option females generally care more about their teeth and looks so wanted more fixed options. The young-old age group preferred removable prosthesis over fixed prosthesis. Patients with implant supported fixed dental prosthesis have a better quality of life compared with patients with implant supported overdentures.
- Published
- 2022
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178. Spatiotemporal dynamics of self-assembled structures in enzymatically induced agonistic and antagonistic conditions.
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Priyanka, Shandilya E, Brar SK, Mahato RR, and Maiti S
- Abstract
Predicting and designing systems with dynamic self-assembly properties in a spatiotemporal fashion is an important research area across disciplines ranging from understanding the fundamental non-equilibrium features of life to the fabrication of next-generation materials with life-like properties. Herein, we demonstrate a spatiotemporal dynamics pattern in the self-assembly behavior of a surfactant from an unorganized assembly, induced by adenosine triphosphate (ATP) and enzymes responsible for the degradation or conversion of ATP. We report the different behavior of two enzymes, alkaline phosphatase (ALP) and hexokinase (HK), towards adenosine triphosphate (ATP)-driven surfactant assembly, which also results in contrasting spatiotemporal dynamic assembly behavior. Here, ALP acts antagonistically, resulting in transient self-assemblies, whereas HK shows agonistic action with the ability to sustain the assemblies. This dynamic assembly behavior was then used to program the time-dependent emergence of a self-assembled structure in a two-dimensional space by maintaining concentration gradients of the enzymes and surfactant at different locations, demonstrating a new route for obtaining 'spatial' organizational adaptability in a self-organized system of interacting components for the incorporation of programmed functionality., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2021
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179. Interconnectivity between Surface Reactivity and Self-Assembly of Kemp Elimination Catalyzing Nanorods.
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Shandilya E, Dasgupta B, and Maiti S
- Abstract
Understanding the fundamental facts behind dynamicity of catalytic processes has been a longstanding quest across disciplines. Herein, we report self-assembly of catalytically active gold nanorods that can be regulated by tuning its reactivity towards a proton transfer reaction at different pH. Unlike substrate-induced templating and co-operativity, the enhanced aggregation rate is due to alteration of catalytic surface charge only during reactivity as negatively charged transition state of reactant (5-nitrobenzisoxazole) is formed on positively charged nanorod while undergoing a concerted E2-pathway. Herein, enhanced diffusivity during catalytic processes might also act as an additional contributing factor. Furthermore, we have also shown that nanosized hydrophobic cavities of clustered nanorods can also efficiently accelerate the rate of an aromatic nucleophilic substitution reaction, which also demonstrates a catalytic phenomenon that can lead to cascading of other reactions where substrates and products of the starting reactions are not directly involved., (© 2021 Wiley-VCH GmbH.)
- Published
- 2021
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180. Data on dental bite materials with stability and displacement under load.
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Kasabwala H, Maiti S, Ashok V, and Sashank K
- Abstract
It is of interest to document the accuracy, time dependent dimensional stability and displacement to load for 5 types of inter-occlusal recording materials. We used cad bite paste, putty, lab putty, pattern resin and poly tray acrylic material in this study. A total of 25 samples were fabricated to evaluate the accuracy and dimensional stability. The amount of displacement was calculated by applying displacing force on the bite registration materials till they fractured using Instron 3000 UTS machine. Statistical analysis of the data shows that CAD bite paste has the maximum amount of accuracy and dimensional stability whereas pattern resin showed the least amount of displacement to applied force. Thus, we report that CAD bite registration material displayed best results in terms of accuracy and dimensional stability and moderate results in terms of displacement to force., Competing Interests: There was no conflict of interest among the authors., (© 2020 Biomedical Informatics.)
- Published
- 2020
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181. Comparative analysis of different impression techniques in relation to single tooth impression.
- Author
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Merchant A, Maiti S, Ashok V, and Ganapathy DM
- Abstract
It is of interest to compare the accuracy of three different impression techniques for a single tooth impression. We used 3 groups with 15 samples each in this study. Group 1: Putty and light body in a sectional stock tray; Group 2: Monophase and extra light body in a sectional stock tray; Group 3: Matrix impression technique. 15 impressions were taken of a prepared tooth on a typodont with each technique. The dimensions of the casts poured from these impression techniques were compared with the control typodont tooth. Data analysis shows that the matrix impression technique gave the best results in terms of dimensional study followed by monophase and extra light body impression technique and putty and light body impression technique gave the least accurate results. The results show that there is a statistically significant difference between the three impression techniques in terms of dimensional stability. Data analysis shows that the matrix impression technique gave the best results in terms of dimensional study followed by monophase and extra light body impression technique and putty and light body impression technique gave the least accurate results. The variations between the groups are within acceptable limits. Hence, it can be concluded that all the impression techniques will result in adequate dimensional stability and can be used in clinical scenarios., (© 2020 Biomedical Informatics.)
- Published
- 2020
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182. Correlation of soft tissue biotype with pink aesthetic score in single full veneer crown.
- Author
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Agarwal S, Maiti S, and Ashok V
- Abstract
It is of interest to document the correlation of soft tissue biotype with pink esthetic score in single full veneer crown in Indian population. Hence, a Cross-sectional, descriptive study was conducted in an institution, on randomly selected individuals from a data collection of 86000 patient data. Scalloped and thin gingival biotype was present in 62.1 % patients and flat and thick was present in 37.9% individuals according to Anon and Ross Classification. Pink esthetic score didn't give any significant value in single crown cases where 85% cases had a good pink aesthetic score. Thus, the rightness of the PES index for the objective outcome assessment of the esthetic dimension of anterior single-tooth crown was confirmed. However, many randomized clinical trials are needed to further validate and refine this index for its clinical use in prosthetic rehabilitation., (© 2020 Biomedical Informatics.)
- Published
- 2020
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183. Temporal Control over Transient Chemical Systems using Structurally Diverse Chemical Fuels.
- Author
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Chen JL, Maiti S, Fortunati I, Ferrante C, and Prins LJ
- Abstract
The next generation of adaptive, intelligent chemical systems will rely on a continuous supply of energy to maintain the functional state. Such systems will require chemical methodology that provides precise control over the energy dissipation process, and thus, the lifetime of the transiently activated function. This manuscript reports on the use of structurally diverse chemical fuels to control the lifetime of two different systems under dissipative conditions: transient signal generation and the transient formation of self-assembled aggregates. The energy stored in the fuels is dissipated at different rates by an enzyme, which installs a dependence of the lifetime of the active system on the chemical structure of the fuel. In the case of transient signal generation, it is shown that different chemical fuels can be used to generate a vast range of signal profiles, allowing temporal control over two orders of magnitude. Regarding self-assembly under dissipative conditions, the ability to control the lifetime using different fuels turns out to be particularly important as stable aggregates are formed only at well-defined surfactant/fuel ratios, meaning that temporal control cannot be achieved by simply changing the fuel concentration., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2017
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184. Water-in-oil microemulsion doped with gold nanoparticle decorated single walled carbon nanotube: scaffold for enhancing lipase activity.
- Author
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Mandal D, Ghosh M, Maiti S, Das K, and Das PK
- Subjects
- Gold chemistry, Lipase chemistry, Lipase metabolism, Metal Nanoparticles chemistry, Nanocomposites chemistry, Nanotubes, Carbon chemistry
- Abstract
The present work reports the development of water-in-oil (w/o) microemulsion doped with newly designed nanocomposite comprising of gold nanoparticle (GNP) decorated single walled carbon nanotube (SWNT). This nanocomposite included cationic reverse micelle was used to boost the catalytic activity of a surface-active enzyme, Chromobacterium viscosum lipase (CV lipase). SWNT was non-covalently dispersed using cetyltrimethylammonium bromide (CTAB), cetylalaninetrimethylammonium chloride (CATAC) while GNP was synthesized by reduction of HAuCl4 with reducing/stabilizing agent trisodium citrate. Counterion exchange between cationic SWNT dispersing agent and anionic capping agent of GNP led to the formation of GNP decorated SWNT (SWNT-GNP) nanocomposite. This newly developed SWNT-GNP included CTAB reverse micelle was characterized by several microscopic and spectroscopic techniques. Interfacially located SWNT-GNP included w/o microemulsion (confirmed from biphasic and fluorescence experiment) was used as a proficient host for enhancing the catalytic activity of lipase. Lipase activity within this self-assembled soft nanocomposite improved up to 3.9-fold (second order rate constant, k2=1694±16 cm(3) g(-1) s(-1)) compared to standard CTAB reverse micelle (k2=433±7 cm(3) g(-1) s(-1)). In case of cetyltripropyl ammonium bromide (CTPAB) based reverse micelle, the observed lipase activity improved to k2=2036±11 cm(3) g(-1) s(-1) in the presence of SWNT-GNP composite. Notably, this catalytic activity of lipase within SWNT-GNP included reverse micelle was till date the highest activity found in any w/o microemulsion. The attainment of flexibility in enzyme conformation at the augmented interface was verified using circular dichroism (CD) spectroscopy., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
185. Graphene oxide in cetyltrimethylammonium bromide (CTAB) reverse micelle: a befitting soft nanocomposite for improving efficiency of surface-active enzymes.
- Author
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Das K, Maiti S, Ghosh M, Mandal D, and Das PK
- Subjects
- Cetrimonium, Circular Dichroism, Horseradish Peroxidase chemistry, Lipase chemistry, Microscopy, Atomic Force, Peroxidases chemistry, Surface Properties, Cetrimonium Compounds chemistry, Enzymes chemistry, Graphite chemistry, Micelles, Nanocomposites chemistry
- Abstract
Herein, we report the successful inclusion of 2D allotrope of carbon, graphene oxide (GO) in cetyltrimethylammonium bromide (CTAB)/isooctane/n-hexanol/water reverse micelle without compromising the stability of water-in-oil (w/o) microemulsion. This newly developed self-assembled nanocomposites act as proficient host for surface-active enzymes, lipase, horseradish peroxidase (HRP), and soybean peroxidase (SBP). Lipase activity within GO-doped CTAB reverse micelles remarkably improved by 3.8-fold compared to that was observed in only CTAB reverse micelle (second-order rate constant, k2=433±7 cm3 g(-1) s(-1)). In case of GO-doped CTAB reverse micelle, the observed enzyme activity (k2=1653±11 cm3 g(-1) s(-1)) is till date the highest ever activity of lipase in CTAB w/o microemulsions. In case of HRP and SBP, the catalytic efficiency maximally increased up to 2.6-fold and 2.3-fold, respectively. Electrostatic attraction between cationic head group of CTAB and anionic surface of GO as well as intrinsic amphiphilic character of GO possibly resulted in the confinement of this 2D nanosheet at the interface of reverse micelles. Integration of GO at the interface augmented the interfacial space in vicinity of surface-active enzyme. This enlarged interface might have accommodated higher amount of substrate and lipase with flexibility in its conformation resulting in marked improvement in the enzyme activity. Interfacial localization of GO was established by fluorescence spectroscopy. In addition, change in secondary structure of lipase in presence of 2D carbon allotrope was substantiated by circular dichroism spectroscopy., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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186. Striking improvement in peroxidase activity of cytochrome c by modulating hydrophobicity of surface-functionalized gold nanoparticles within cationic reverse micelles.
- Author
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Maiti S, Das K, Dutta S, and Das PK
- Subjects
- Cations chemistry, Cations metabolism, Cytochromes c chemistry, Enzyme Activation, Gold metabolism, Hydrophobic and Hydrophilic Interactions, Micelles, Models, Molecular, Molecular Structure, Peroxidase chemistry, Surface Properties, Cytochromes c metabolism, Gold chemistry, Metal Nanoparticles chemistry, Peroxidase metabolism
- Abstract
This work demonstrates a remarkable enhancement in the peroxidase activity of mitochondrial membrane protein cytochrome c (cyt c) by perturbing its tertiary structure in the presence of surface-functionalised gold nanoparticles (GNPs) within cetyltrimethylammonium bromide (CTAB) reverse micelles. The loss in the tertiary structure of cyt c exposes its heme moiety (which is buried inside in the native globular form), which provides greater substrate (pyrogallol and H(2)O(2)) accessibility to the reactive heme residue. The surfactant shell of the CTAB reverse micelle in the presence of co-surfactant (n-hexanol) exerted higher crowding effects on the interfacially bound cyt c than similar anionic systems. The congested interface led to protein unfolding, which resulted in a 56-fold higher peroxidase activity of cyt c than that in water. Further perturbation in the protein's structure was achieved by doping amphiphile-capped GNPs with varying hydrophobicities in the water pool of the reverse micelles. The hydrophobic moiety on the surface of the GNPs was directed towards the interfacial region, which induced major steric strain at the interface. Consequently, interaction of the protein with the hydrophobic domain of the amphiphile further disrupted its tertiary structure, which led to better opening up of the heme residue and, thereby, superior activity of the cyt c. The cyt c activity in the reverse micelles proportionately enhanced with an increase in the hydrophobicity of the GNP-capping amphiphiles. A rigid cholesterol moiety as the hydrophobic end group of the GNP strikingly improved the cyt c activity by up to 200-fold relative to that found in aqueous buffer. Fluorescence studies with both a tryptophan residue (Trp59) of the native protein and the sodium salt of fluorescein delineated the crucial role of the hydrophobicity of the GNP-capping amphiphiles in improving the peroxidase activity of cyt c by unfolding its tertiary structure within the reverse micelles., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2012
- Full Text
- View/download PDF
187. Unmodified "GNP-oligonucleotide" nanobiohybrids: a simple route for emission enhancement of DNA intercalators.
- Author
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Maiti S, Dutta S, and Das PK
- Subjects
- Particle Size, Quantum Theory, Surface Properties, DNA, Single-Stranded chemistry, Gold chemistry, Metal Nanoparticles chemistry, Nanotechnology methods, Oligonucleotides chemistry
- Abstract
We present herein a simple method for enhancing the emission of DNA intercalators in homogeneous nanobiohybrids of unlabeled oligonucleotides and unmodified gold nanoparticles (GNPs). Pristine single-stranded DNA (ss-DNA) has been wrapped around unmodified GNPs to induce metal-enhanced fluorescence (MEF) of DNA intercalators, such as ethidium bromide and propidium iodide. The thickness of the ss-DNA layer on the gold nanosurface determines the extent of MEF, since this depends on the position of the intercalator in relation to the metal surface. Presumably, at a suitable thickness of this DNA layer, more of the intercalator is localized at the optimum distance from the nanoparticle to give rise to MEF. Importantly, no external spacer or coating agent was needed to induce the MEF effect of the GNPs. The concentration ratios of Au to DNA in the nanohybrids, as well as the capping agents applied to the GNPs, play key roles in enhancing the emission of the intercalators. The dimensions of both components of the nanobiohybrids, that is, the size of the GNPs and the length of the oligonucleotide, have considerable influences on the emission enhancement of the intercalators. Emission intensity increased with increasing size of the GNPs and length of the oligonucleotide only when the DNA efficiently wrapped the nanoparticles. An almost 100 % increment in the quantum yield of ethidium bromide was achieved with the GNP-DNA nanobiohybrid compared with that with DNA alone (in the absence of GNP), and the fluorescence emission was enhanced by 50 % even at an oligonucleotide concentration of 2 nM. The plasmonic effect of the GNPs in the emission enhancement was also established by the use of similar nanobioconjugates of ss-DNA with nonmetallic carbon nanoparticles and TiO(2) nanoparticles, with which no increase in the fluorescence emission of ethidium bromide was observed., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2011
- Full Text
- View/download PDF
188. Influence of gold nanoparticles of varying size in improving the lipase activity within cationic reverse micelles.
- Author
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Maiti S, Das D, Shome A, and Das PK
- Subjects
- Catalysis, Cations chemistry, Cetrimonium, Cetrimonium Compounds chemistry, Circular Dichroism, Hexanols chemistry, Gold chemistry, Lipase metabolism, Micelles, Nanoparticles chemistry, Surface-Active Agents chemistry
- Abstract
Herein, we report the effect of gold nanoparticles (GNPs) in enhancing lipase activity in reverse micelles of cetyltrimethylammonium bromide (CTAB)/water/isooctane/n-hexanol. The size and concentration of the nanoparticles were varied and their specific roles were assessed in detail. An overall enhancement of activity was observed in the GNP-doped CTAB reverse micelles. The improvement in activity becomes more prominent with increasing concentration and size of the GNPs (0-52 microM and ca. 3-30 nm, respectively). The observed highest lipase activity (k(2)=1070+/-12 cm(3) g(-1) s(-1)) in GNP-doped CTAB reverse micelles ([GNP]: 52 microm, ca. 20 nm) is 2.5-fold higher than in CTAB reverse micelles without GNPs. Improvement in the lipase activity is only specific to the GNP-doped reverse micellar media, whereas GNP deactivates and structurally deforms the enzyme in aqueous media. The reason for this activation is probably due to the formation of larger-sized reverse micelles in which the GNP acts as a polar core and the surfactants aggregate around the nanoparticle ('GNP pool') instead of only water. Lipase at the augmented interface of the GNP-doped reverse micelle showed improved activity because of enhancement in both the substrate and enzyme concentrations and increased flexibility in the lipase conformation. The extent of the activation is greater in the case of the larger-sized GNPs. A correlation has been established between the activity of lipase and its secondary structure by using circular dichroism and FTIR spectroscopic analysis. The generalized influence of GNP is verified in the reverse micelles of another surfactant, namely, cetyltripropylammonium bromide (CTPAB). TEM, dynamic light scattering (DLS), and UV/Vis spectroscopic analysis were utilized to characterize the GNPs and the organized aggregates. For the first time, CTAB-based reverse micelles have been found to be an excellent host for lipase simply by doping with appropriately sized GNPs.
- Published
- 2010
- Full Text
- View/download PDF
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