Epoxidized soybean oil modified using fatty acids as tougheners for thermosetting epoxy resins: Part 1

A series of bio-rubber (BR) reactive tougheners for thermosetting epoxy resins was prepared by grafting renewable saturated fatty acids of different chain lengths (C6-C14) onto epoxidized soybean oil (ESO) at varying molar ratios. The tunable nature of the BR systems derives from the architecture and functionality of naturally occurring molecules. Control of BR reactivity and molecular weight by varying the degree of grafting and the chain length of the fatty acid was demonstrated. The BR-toughened samples were prepared by blending BRs with diglycidyl ether of bisphenol A (DGEBA), Epon 828, and stoichiometrically curing the mixture using an aromatic amine hardener, diethyl toluene diamine (Epikure W). Fracture surface morphology studies showed that tuning of phase separated particle sizes was possible depending on the BR type and weight fraction. The resulting toughening effect was evaluated by measuring the fracture toughness of control and toughened polymer samples. The use of BRs significantly improved the critical strain energy release rate and critical stress intensity factor values of thermosetting polymer samples without significantly reducing T_g and modulus. In addition to toughening and adding renewable content to petroleum-based thermosetting epoxy systems these new tougheners have low viscosity compared to common alternatives and aid ease of processing.     

Epoxidized soybean oil modified using fatty acids as tougheners for thermosetting epoxy resins: Part 2—Effect of curing agent and epoxy molecular weight

A series of bio-rubber (BR) tougheners for thermosetting epoxy resins was prepared by grafting renewable fatty acids with different chain lengths onto epoxidized soybean oil at varying molar ratios. BR-toughened samples were prepared by blending BRs with diglycidyl ether of bisphenol A resins, Epon 828 and Epon 1001F, at different weight fractions and stoichiometrically cured using an amine curing agent, 4, 4′-methylene biscyclohexanamine (PACM). Fracture toughness properties of the unmodified and BR toughened polymer samples—including critical strain energy release rate (G_Ic), and critical stress intensity factor (K_Ic)—were measured to investigate the toughening effect of prepared BRs. It was found that the degree of phase separation and toughening were more controllable relative to similar polymers cured using the aromatic curing agent Epikure W, and the use of higher molecular epoxy resins produces a synergistic effect increasing the toughness much more than similar polymers made with lower molecular weight epoxy resins. Average BR domain sizes ranging from 200 to 900 nm were observed, and formulations with G_Ic, values K_Ic as high as 1.0 kJ/m² and 1.4 MPa m^1/2 were attained respectively for epoxy systems with T_g greater than 130°C.     

Bitter Taste Receptor T2R14 Modulates Gram-Positive Bacterial Internalization and Survival in Gingival Epithelial Cells

Bitter-taste receptors (T2Rs) have emerged as key players in host–pathogen interactions and important modulators of oral innate immunity. Previously, we reported that T2R14 is expressed in gingival epithelial cells (GECs) and interacts with competence stimulating peptides (CSPs) secreted by the cariogenic Streptococcus mutans. The underlying mechanisms of the innate immune responses and physiological effects of T2R14 on Gram-positive bacteria are not well characterized. In this study, we examined the role of T2R14 in internalization and growth inhibitory effects on Gram-positive bacteria, namely Staphylococcus aureus and S. mutans. We utilized CRISPR-Cas9 T2R14 knockdown (KD) GECs as the study model to address these key physiological mechanisms. Our data reveal that the internalization of S. aureus is significantly decreased, while the internalization of S. mutans remains unaffected upon knockdown of T2R14 in GECs. Surprisingly, GECs primed with S. mutans CSP-1 resulted in an inhibition of growth for S. aureus, but not for S. mutans. The GECs infected with S. aureus induced T2R14-dependent human β-defensin-2 (hBD-2) secretion; however, S. mutans–infected GECs did not induce hBD-2 secretion, but induced T2R14 dependent IL-8 secretion. Interestingly, our results show that T2R14 KD affects the cytoskeletal reorganization in GECs, thereby inhibiting S. aureus internalization. Our study highlights the distinct mechanisms and a direct role of T2R14 in influencing physiological responses to Gram-positive bacteria in the oral cavity.     

Fullerene polymer film as a highly efficient photocatalyst for selective solar fuel production from CO2

C₆₀-based polymeric systems have been constantly anticipated for sustainable solar energy conversion. Reported, herein is a C₆₀ polymer film as visible light active photocatalyst for efficient and selective reduction of CO₂ for the first time. The C₆₀ polymer photocatalyst is synthesized via covalent coupling of C₆₀ monomer units consisting of tetra substituted C₆₀-pyrene conjugates through spacer groups. The synthesized C₆₀ polymer photocatalyst possesses an extended network of well-defined repeating monomer units with good stability and visible light-induced photocatalytic activity. The enhanced visible light harvesting ability of C₆₀ polymer photocatalyst reasonably yields it with higher catalytic ability than its monomer unit. The C₆₀ polymer film photocatalyst upon coupling with the biocatalyst carries out highly selective visible light driven reduction of CO₂ to HCOOH (239.46 μmol). The tandem way of incorporating C₆₀ into visible light active polymeric films for continuous use may be highly rewarding for their extended photocatalytic activity for solar fuel production from CO₂. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48536.     

Efficacious Doxorubicin Delivery Using Glutathione-Responsive Hollow Non-phospholipid Vesicles Bearing Lipoyl Cholesterols

In this study, we developed redox-sensitive vesicles using synthesised lipoyl cholesterol derivatives, a non-ionic surfactant and an optimum level of free cholesterol. Interestingly, concentration-dependent self-assembly was observed by scanning electron microscopy, wherein vesicles manifested as hollow spherical (at 0.15 mm ) and triangular (0.50 mm ). The redoxresponsive characteristics of the vesicles was probed in the presence of dithiothreitol; they underwent a clear increase in size as observed by dynamic light scattering measurements. These vesicles could easily encapsulate an anticancer drug, doxorubicin, and were observed to be stable in the presence of serum. They showed substantial release of the drug in response to biologically relevant stimulus, that is, glutathione. A toxicity assessment on HeLa and HepG2 cancer cells demonstrated activities of the drug-loaded vesicles comparable to that of free drug, whereas significantly enhanced toxicity and apoptotic induction were observed against drug-resistant HeLa cells, which was determined by studying the cellular internalisation of doxorubicin.     

Discovery of Aporphine Analogues as Potential Antiplatelet and Antioxidant Agents: Design,Synthesis, Structure–Activity Relationships,Biological Evaluations,and in silico Molecular Docking Studies

To explore the potential of aporphine alkaloids, a novel series of functionalized aporphine analogues with alkoxy (OCH₃, OC₂H₅, OC₃H₇) functional groups at C1/C2 of ring A and an acyl (COCH₃ and COPh) or phenylsulfonyl (SO₂Ph and SO₂C₆H₄‐3‐CH₃) functionality at the N6 position of ring B of the aporphine scaffold were synthesized and evaluated for their arachidonic acid (AA)‐induced antiplatelet aggregation inhibitory activity and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free‐radical‐scavenging antioxidant activity, with acetylsalicylic acid and ascorbic acid as standard references, respectively. The preliminary structure–activity relationship related to AA‐induced platelet aggregation inhibitory activity results showed that the aporphine analogues 1‐[1,2,9,10‐tetramethoxy‐6a,7‐dihydro‐4H‐dibenzo[de,g]quinolin‐6(5H)‐yl]ethanone and 1‐[2‐(benzyloxy)‐1,9,10‐trimethoxy‐6a,7‐dihydro‐4H‐dibenzo[de,g]quinolin‐6(5H)‐yl]ethanone to be the best compounds of the series. Moreover, the DPPH free‐radical‐scavenging antioxidant activity results demonstrated that the aporphine analogues 1,2,9,10‐tetramethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 2‐ethoxy‐1,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 1‐ethoxy‐2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐1‐propoxy‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, and 1‐(benzyloxy)‐2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline were the best compounds of the series. Moreover, in silico molecular docking simulation studies of the active analogues were also performed.     

Tent-Shaped Surface Morphologies of Silicon: Texturization by Metal Induced Etching

Silicon - Nano-metal/semiconductor junction dependent porosification of silicon has been studied here. The silicon nanostructures (SiNSs) have been textured on n- and p- type silicon wafers using...     

IE2M: Design of intellectual energy efficient multicast routing protocol for ad-hoc network

In this paper, an intellectual energy efficient multicast routing protocol is proposed. It achieves enhanced performance over On-Demand Multicast Routing Protocol (ODMRP). The proposed protocol finds energy efficient multicast routes from source node to a group of receivers. Multicast mesh creation involves two phases: a Join Query (J-Q) phase and a Join Reply (J-R) phase. The J-Q phase initiates a route discovery process to find routes of the multicast group. In J-R phase, different routes of the multicast groups are set up. In the proposed protocol, we modify ODMRP and introduce fuzzy inference system to deal with imprecise and partial information during the route discovery phase. The decision maker uses two fuzzy variables such as energy and distance for evaluating reward as an output parameter of each multicast route. This output parameter helps to distinguish different multicast route and it also helps to reduce the effect of mutual interference between routes. The proposed protocol is simulated using the NS-2 simulator. The performance of the proposed protocol is compared with existing multicast routing protocols, and results outperform existing protocols in terms of several network metrics.     

Sentiment Analysis with Tweets Behaviour in Twitter Streaming API

Twitter is a radiant platform with a quick and effective technique to analyze users’ perceptions of activities on social media. Many researchers and industry experts show their attention to Twitter sentiment analysis to recognize the stakeholder group. The sentiment analysis needs an advanced level of approaches including adoption to encompass data sentiment analysis and various machine learning tools. An assessment of sentiment analysis in multiple fields that affect their elevations among the people in real-time by using Naive Bayes and Support Vector Machine (SVM). This paper focused on analysing the distinguished sentiment techniques in tweets behaviour datasets for various spheres such as healthcare, behaviour estimation, etc. In addition, the results in this work explore and validate the statistical machine learning classifiers that provide the accuracy percentages attained in terms of positive, negative and neutral tweets. In this work, we obligated Twitter Application Programming Interface (API) account and programmed in python for sentiment analysis approach for the computational measure of user’s perceptions that extract a massive number of tweets and provide market value to the Twitter account proprietor. To distinguish the results in terms of the performance evaluation, an error analysis investigates the features of various stakeholders comprising social media analytics researchers, Natural Language Processing (NLP) developers, engineering managers and experts involved to have a decision-making approach.