Removal of micropollutants through bio-based materials as a transition to circular bioeconomy: Treatment processes involved, perspectives and bottlenecks.

The recent increase in micropollutant levels in water bodies is a growing concern globally. The generation of new materials and techniques for wastewater treatment often involves the release of hazardous wastes and the utilization of energy related to it. This can be resolved by the synthesis of bio-based materials through the use of already released wastes and naturally occurring components, adding their value as reusable resources. These bio-based materials find wide applications for micropollutant elimination and energy tapping due to the presence of various functional groups, large surface area, high stability, and reusability. The processes involved in micropollutant elimination through biomaterials generally include adsorption and degradation. These treatment processes are suggested to depend on various operational parameters like pH, temperature, dose, reaction time, presence of other contaminants, ions, etc. in the system, which may influence the process efficiency. Understanding the potential of bio-based materials many steps can be taken towards its large-scale application to upgrade wastewater treatment plants for micropollutant elimination. Furthermore, the recent advances of bio-based materials in energy storage and conversion have widened its scope for implementation in a circular bioeconomy. The bottlenecks towards such a transition and future recommendations are also presented and discussed.

Facile synthesis and characterisation of AlNs using Protein Rich Solution extracted from sewage sludge and its application for ultrasonic assisted dye adsorption: Isotherms, kinetics, mechanism and RSM design.

Protein Rich Solution (PRS) was prepared from the sewage sludge with ultrasonic assistance. With PRS, aluminium based nanosheet like materials (AlNs) were synthesised for the ultrasonic removal of Congo Red (CR) and Crystal Violet (CV) dyes. PRS was characterised by UV, EEM and NMR spectral analysis. AlNs were characterised by FTIR, XRD, TGA, BET, SEM, AFM, TEM and XPS analysis. The point of zero charge of AlNs was found to be 5.4. The BET analysis ensured that the average pore diameter and total pore volume of AlNs as 8.464 nm and 0.11417 cc/g respectively. The efficacy of AlNs for the removal of toxic dyes was tested by performing Response surface methodology (RSM) designed experiments. The effect of sonication time, dosage and initial concentration on dye removal was studied at an optimised pH value. Langmuir, Freundlich and Temkin isotherm models were examined. The maximum adsorption capacity was found to be 121.951 and 105.263 mg/g for CR and CV respectively. The kinetic models like pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion were examined to understand the mechanism behind it. The results revealed that the use of ultrasonication enhanced the mass transfer. The experimental studies on the influence of ultrasound power indicated a positive relation with the removal efficiency. The results of thermodynamic study revealed that the process was spontaneous and exothermic for both the dyes. The increase in ionic strength increased the removal efficiency for both CR and CV. RSM predicted the optimum adsorbent dosages as 0.16 g for 50 mg/L of CR and 0.12 g for 100 mg/L of CV dye solutions. The values of half-life and fractional adsorption for both CR and CV suggested that the low cost AlNs has high potential to remove the toxic industrial dyes.

Sustainable papaya plant waste and green tea residue composite films integrated with starch and gelatin for active food packaging applications.

This study explores the sustainable utilization of wastes from a papaya plant (papaya peels (PP), papaya seeds (PS), leaf-stem (PL)) and dried green tea residues (GTR) for the synthesis of bioplastics. The dried GTR were individually blended with each papaya waste extract and then boiled in water to get three composite papaya plant waste-green tea supernatants. Potato starch and gelatin-based functional films were prepared by integrating each with the composite papaya waste-green tea supernatant liquid. This work introduces a dissolved organic matter (DOM) study to the field of bioplastics, with the goal of identifying the organic components and macromolecules inherent in the PW supernatants. When compared with the films prepared solely from papaya waste (PW) supernatants, PW-GTR composite supernatant films prevent UV light transmission with superior antioxidant and mechanical properties. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopy (XRD), and atomic force microscopy (AFM) were utilized to characterize the starch and gelatin PW-GTR films. Owing to the exceptional antioxidant, UV barrier, and remarkable biodegradable properties of the starch/PW/GTR and gelatin/PW/GTR composite films, make them ideal for use in food packaging applications.

Ageing behavior of starch-based food packaging bioplastics in riparian sediments and sediment-derived dissolved organic matter in the soil environment.

Riparian sediment (RS) is a translational zone separating aquatic and terrestrial ecosystems. To this date, the bioplastic's UV ageing and biodegradation features in these contaminated sediments remain unknown. It is a considerable concern to investigate whether a food packaging film can interact with RS and riparian sediment-derived Dissolved Organic Matter (RS-DOM) during biodegradation and UV ageing respectively, after disposal in a natural environmental setting. To address this research gap, for the first time, this study investigates the biodegradation and UV ageing of starch/PPst/GTR films intended for food packaging applications in RS and RS-DOM respectively. The findings revealed that RS comprises major fulvic acid DOM components. Remarkably, research demonstrates the leaching of humic acid-like DOM from the film promotes aromaticity and humification as UV ageing progresses from the third to the tenth day. Comparable DOM samples were darkly analysed, revealing aromatic proteins I and II. Furthermore, an elevated carbonyl carboxyl index confirmed significant degradation of films during UV ageing. Lesser humification, aromaticity, and higher biological activity were confirmed by a HI < 10 and BIX > 0.6 respectively. In comprehension, these findings reveal that the starch/PPst/GTR food packaging film will have a lesser adverse environmental impact after disposal, offering a hopeful outlook for the future of bioplastics.

Comparative Spectrophotometric Assessment of Color Stability of Two Hybrid Composite Materials in an Oral Environment when Exposed to Various Liquids.

Introduction: The primary intent of this scientific research is to effectively assess and collate the inherent potentiality of the two selected investigative composite materials in effectual maintenance of their standard color following subsequent and consistent submersion in customary available pediatric liquids consumed by children. The above investigation will be effectively estimated using the Commission Internationale de I'Eclairege (CIE) L*a*b* system-based spectrophotometer. Materials and methods: A total of 100 composites of spheroidal plates were fabricated accordingly. A total of 50 nanohybrids and microhybrids of 8 × 2 mm were fabricated and timely cured using a light cure unit for an approximated time period of 40 seconds. This was then trialled by subsequent sample submersion in the specified five immersive media, which include mineral water, tea, Mirinda, pomegranate juice, and iron syrup, respectively, for a definitive and habitual time of thrice daily up to 15 minutes for a duration of 28 experimental days. The respective marked readings were recorded on the 7th, 14th, 21st, and 28th days by utilization of a CIE L*a*b* system-based spectrophotometer. Results: Mann-Whitney U test and Friedman's Test were utilized for statistical evaluation of the above-described experimental research. The p-value was statistically found to be significant at (p < 0.001). Conclusion: The conclusive findings from the above-defined experimental research were that iron syrup was found to cause the most noticeable and definitive staining in comparison to other immersive media. Nanohybrid composite restorative material was hence identified as being highly resistant to staining and possessing an undeniable ability to maintain the persistent color, unlike its microhybrid counterpart. Clinical significance: The esthetic appearance is an important factor for both the parents and children; hence, this determines that the longevity of color stability of restorative materials is of valid significance. How to cite this article: Thribhuvanan L, MS S, Gopalakrishnan A, et al. Comparative Spectrophotometric Assessment of Color Stability of Two Hybrid Composite Materials in an Oral Environment when Exposed to Various Liquids. Int J Clin Pediatr Dent 2024;17(2):176-183.

Fiber technology in space maintainer: a clinical follow-up study.

Various space maintainers are used in pediatric dentistry. However, their construction requires time consuming laboratory procedures. Recently fiber-reinforced composite resin (FRCR) has been introduced for various application in dentistry. Polyethylene fibers appear to have the best properties in elasticity, translucency, adaptability, tenaciousness, resistance to traction and to impact. The purpose of this study was to clinically evaluate the long-term effect of FRCR space maintainer made with Ribbond(®) bondable reinforcement ribbon in children over a period of 18 months. A total of thirty FRCR space maintainers were applied to 30 children between the age group of 6 to 9 years old, follow-up visits were done at 1, 6, 12 and 18 months. The data obtained was subjected to statistical analysis. Maxillary appliances survived more than mandibular appliances. Mean survival time of space maintainer were found to be 12 months (minimum 1 and maximum 18 months). The present study suggested that FRCR space maintainers (Ribbond(®)), which was observed for up to 18 months, can be accepted as a successful alternative to conventional band-loop space maintainer only for short periods.

New insights on aging mechanism of microplastics using PARAFAC analysis: Impact on 4-nitrophenol removal via Statistical Physics Interpretation.

The aging effects of Polyethylene terephthalate (PET) microplastics were studied under Fenton process and Seawater. This research work mainly focuses on the aging mechanism of PET microplastics under two different conditions and their effect of aging on the adsorption of organic contaminants. The results of optical microscopic images, Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman Spectroscopy, carbonyl, carboxyl index, X-ray powder diffraction (XRD) and dissolved organic carbon (DOC) help to understand the aging mechanism of PET microplastics. Parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy (2D-COS) were performed using 3D Excitation-Emission Matrix (3D-EEM) to understand the possible dissolved organic matter released during the Fenton process and seawater. The release of protein/phenol like components was observed in seawater whereas humic acid-like component was noted in the Fenton process. Later, the aged PET microplastics were tested for their adsorption capacity towards 4-nitrophenol at three different temperatures (15, 30 and 45 °C). The adsorption capacity of aged microplastics was found to be higher than the normal PET microplastics for all three different temperatures. Hydrogen bonding, n-pi interaction performed a significant role than pi-pi and hydrophobic interaction in the adsorption mechanism. A double layer with double energy model was found to be the best fit in the adsorption processes. The calculated adsorption energies (ΔE1, ΔE2) from the statistical physics modeling also confirms the physisorption mechanism. The above experimental results help to understand the behavior of microplastics at different aging period and how it acts as a carrier for pollutant in the marine environment.

Characterization of anthocyanin from red sorghum (Sorghum bicolor) bran by liquid chromatography-electron spray ionization mass spectrometry analysis.

In the present study, anthocyanin pigments from red sorghum (Sorghum bicolor) bran were identified and characterized by Liquid Chromatography-Electron Spray Ionization Mass Spectrometry. The individual anthocyanins were identified by comparing their mass spectrometric data and retention times, published data. 3-deoxyanthocyanidins and methyl 3-deoxyanthocyanidins were identified in red sorghum bran. This paper presents complete LCMS profile and MS spectrometric data of red sorghum bran.

Co-cultivation of Streptomyces and microalgal cells as an efficient system for biodiesel production and bioflocculation formation.

The phytohormone producing Streptomyces rosealbus MTTC 12,951 (S.R) and green microalga Chlorella vulgaris MSU-AGM 14 (C.V) were cultivated in co-culture system to evaluate exogenous hormonal activity. Biosynthesis of indole-3-acetic acid (IAA) and their precursors were quantitatively evaluated by employing High Performance Liquid Chromatography (HPLC). The concentration of IAA (0.72 ± 0.02 µg mL-1) was observed to be elevated in co-cultivation system due to symbiotic interaction between Streptomyces and microalgae. In exchange, microalgae produced adequate volume of tryptophan (Trp) to induce IAA biosynthesis. The Trp stress in late exponential phase encouraged lipid accumulation (175 ± 10 mg g-1). The bioflocculation property of microalgae ensures potential and economic viable harvesting process by reducing 148% input energy compared to conventional method. The overall results evidenced that C.V co-cultivation with S.R exhibits promotional behavior and serves as a promising cultivation process for microalgae in terms of cost efficiency and energy conservation.

A Comparative Evaluation of Remineralizing Potential of Three Commercially Available Remineralizing Agents: An In Vitro Study.

AIM: An in vitro study to evaluate and compare the remineralization potential of commercially available remineralizing agents containing silver diamine fluoride (SDF), casein sucrose phosphate (CSP), casein phospho peptide-amorphous calcium phosphate (CPP-ACP) using DIAGNOdent. MATERIALS AND METHODS: Thirty freshly extracted premolars for orthodontic treatment were collected. Specimens were randomly divided into 3 groups of 10 each: group I: SDF, group II: CSP, group III: CPP-ACP. The samples were subjected to DIAGNOdent analysis for recording the baseline values. Specimens were placed in demineralizing solution incubated at 37°C for 72 hours. DIAGNOdent values were recorded after demineralization. Following this, remineralization procedure was carried out using 3 different remineralizing agents: group I samples with SDF, group II with CSP, and group III with CPP-ACP. The remineralization procedure was performed to group I once and repeated for 14 days for group II and group III and storage solution was changed every 24 hours. The samples were subjected to DIAGNOdent analysis after 72 hours, 7 days, and 14 days and values were recorded. RESULTS: The data were analysed using Statistical Package for the Social Sciences (SPSS) with analysis of variance (ANOVA) and post hoc test. Intragroup comparison of DIAGNOdent readings showed a highly significant difference between baseline, postdemineralization, and postremineralization values. Among intergroup comparison, SDF showed maximum remineralization values followed by CSP and CPP-ACP, respectively. CONCLUSION: Silver diamine fluoride, CSP, and CPP-ACP are proven to possess remineralization potential. CLINICAL SIGNIFICANCE: A comparative evaluation of these three remineralizing agents will aid in identifying most potent and effective agent in treating initial caries lesions in an effective noninvasive and child-friendly manner. HOW TO CITE THIS ARTICLE: Vinod D, Gopalakrishnan A, Subramani SM, et al. A Comparative Evaluation of Remineralizing Potential of Three Commercially Available Remineralizing Agents: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(1):61-65.

Evaluation of Antimicrobial Efficacy and Penetration Depth of Various Irrigants into the Dentinal Tubules with and without Lasers: A Stereomicroscopic Study.

AIM: To evaluate and compare the antibacterial efficacy and horizontal depth of penetration of various irrigants into the dentinal tubules when used alone and when combined with lasers. MATERIALS AND METHODS: An experimental study was done on 42 single-rooted teeth. Access cavity preparation was done and the canals were enlarged up to a ProTaper file size F2 of length 25 mm. They were inoculated with 0.1 mL of Enterococcus faecalis and the samples were randomly assigned into six different groups of seven teeth each. The following irrigation systems were used individually and in combinations-normal saline, sodium hypochlorite, chlorhexidine gluconate, diode laser and erbium, chromium: ytrrium scandium gallium garnet laser (Er,Cr:YSGG laser). The colony-forming units (CFU) of bacteria before and after disinfection and the penetration depth of different groups were determined. Statistical analysis was done by an ANOVA test. RESULTS: The highest number of CFU of bacteria was shown by the group where saline was used and it also showed the least penetration depth compared to that of the Er,Cr:YSGG laser group. CONCLUSION: Er,Cr:YSGG laser when used along with sodium hypochlorite and chlorhexidine gluconate showed the highest reduction in the CFU of bacteria and the greatest penetration depth when observed under a stereomicroscope. CLINICAL SIGNIFICANCE: Laser-assisted irrigation regimes have a high antibacterial efficacy and more penetration depth into the dentinal tubules. HOW TO CITE THIS ARTICLE: Subramani SM, Anjana G, et al. Evaluation of Antimicrobial Efficacy and Penetration Depth of Various Irrigants into the Dentinal Tubules with and without Lasers: A Stereomicroscopic Study. Int J Clin Pediatr Dent 2019;12(4):273-279.

Facile synthesis, growth process, characterisation of a nanourchin-structured α-MnO2 and their application on ultrasonic-assisted adsorptive removal of cationic dyes: A half-life and half-capacity concentration approach.

Textile dyes pose a serious threat in terms of water pollution due to its complex aromatic structures and poor degradability. In order to reduce the toxic effects of Crystal Violet (CV) and Methylene Blue (MB), an ultrasonic-assisted dye adsorption using urchin like α-MnO2 nanostructures was studied. The adsorbent was synthesised by hydrothermal method at low-temperature. The crystallinity and morphology were determined to investigate the growth mechanism of α-MnO2 nanourchins which consists of two main stages. The initial stage includes the formation of α-MnO2 microspheres followed by the epitaxial growth of nanoneedles on to the surface of them. The α-MnO2 was characterised by BET, XRD, FT-IR, XPS, SEM, TEM and TGA. At 5.6, the point of zero charge of α-MnO2 nanostructures was determined. The total pore volume and average pore radius were confirmed to be 4.751 × 10-2 cc/g and 10.99 Šrespectively from the BET analysis. Batch adsorption experiments were performed to investigate the effect of pH, adsorbent dosage, sonication time, initial dye concentration, temperature, ultrasonic frequency and power. The adsorption mechanism was studied using several isotherm and kinetic models. The adsorption data of CV and MB at equilibrium was observed to adopt the Langmuir isotherm model and pseudo-second order kinetic model. The maximum adsorption capacities for CV and MB were found to be 5882.3 and 5000 mg/g respectively. The thermodynamic study predicted that the process was exothermic for CV and endothermic for MB. The effects of competitive ions, ionic strength and humic acid on the uptake of both the dyes were also investigated. And finally, the reusability of recovered α-MnO2 after dye adsorption was studied up to five cycles for its potential industrial applications.

Biosynthesised magnetic iron nanoparticles for sludge dewatering via Fenton process.

The magnetic iron nanoparticles (MFeNp) were biosynthesised using the extract of Cinnamomum tamala (bay leaf) and examined for its efficacy on sludge dewatering. The characteristics of MFeNp were studied using scanning electron microscope (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectrometer (XPS) techniques. The presence of polyphenolic compounds were confirmed by FTIR and XPS analysis. The reduction in capillary suction time (CST) (71.36 to 16.5 s) and specific resistance to filtration (SRF) (53.71 × 1011 to 1.47 × 1011 m/kg) values have indicated that the use of Fenton nanocatalyst enhanced the sludge dewaterability. The differential scanning calorimetry (DSC) analysis has shown that the mass of bound water in the treated sludge was decreased significantly from 1.45 to 0.92 kg H2O/kg DS. The breakdown of extracellular polymeric substances (EPS) by the MFeNp leads to the significant reduction in proteins, polysaccharides, water content and heavy metals. The optimisation using response surface modelling (RSM) have shown that the maximum removal efficiency of water from the sludge was 85.9 % when the optimum pH (3) MFeNp dosage (50 mg/g DS) and H2O2 dosage (500 mg/g DS) were maintained. The experimental results and the statistical optimisation have suggested that MFeNp can be used as a potential nanocatalyst for the sludge dewaterability and hence it can be used for the agricultural purpose. Graphical abstract Schematic representation of sludge dewatering process.

Engineering sugarcane cultivars with bovine pancreatic trypsin inhibitor (aprotinin) gene for protection against top borer (Scirpophaga excerptalis Walker).

The inhibitory activity of bovine pancreatic trypsin inhibitor (aprotinin), a natural polypeptide and a proteinase inhibitor, was demonstrated on gut proteinases of three lepidopteran borers of sugarcane using commercially available aprotinin. A synthetic gene coding for aprotinin, designed and codon optimized for better expression in plant system (Shantaram 1999), was transferred to two sugarcane cultivars namely CoC 92061 and Co 86032 through particle bombardment. Aprotinin gene expression was driven by maize ubiquitin promoter and the plant selection marker used was hygromycin resistance. The integration, expression and functionality of the transgene was confirmed by Southern, Western and insect bioassay, respectively. Southern analysis showed two to four integration sites of the transgene in the transformed plants. Independent transgenic events showed varied levels of transgene expression resulting in different levels (0.16-0.50%) of aprotinin. In in vivo bioassay studies, larvae of top borer Scirpophaga excerptalis Walker (Lepidoptera: Pyralidae) fed on transgenics showed significant reduction in larval weight which indicated impairment of their development. Results of this study show the possibility of deploying aprotinin gene for the development of transgenic sugarcane cultivars resistant to top borer.

Buffalo (Bubalus bubalis) interleukin-2: sequence analysis reveals high nucleotide and amino acid identity with interleukin-2 of cattle and other ruminants.

A 4400-bp genomic sequence and a 332-bp truncated cDNA sequence of the interleukin-2 (IL-2) gene of Indian water buffalo (Bubalus bubalis) were amplified by polymerase chain reaction and cloned. The coding sequence of the buffalo IL-2 gene was assembled from the 5' end of the genomic clone and the truncated cDNA clone. This sequence had 98.5% nucleotide identity and 98% amino acid identity with cattle IL-2. Three amino acid substitutions were observed at positions 63, 124 and 135. Comparison of the predicted protein structure of buffalo IL-2 with that of human and cattle IL-2 did not reveal significant differences. The putative amino acids responsible for IL-2 receptor binding were conserved in buffalo, cattle and human IL-2. The amino acid sequence of buffalo IL-2 also showed very high identity with that of other ruminants, indicating functional cross-reactivity.