Fingerprints for Structural Defects in Poly(thienylene vinylene) (PTV): A Joint Theoretical–Experimental NMR Study on Model Molecules

In the field of plastic electronics, low band gap conjugated polymers like poly(thienylene vinylene) (PTV) and its derivatives are a promising class of materials that can be obtained with high molecular weight via the so-called dithiocarbamate precursor route. We have performed a joint experimental- theoretical study of the full NMR chemical shift assignment in a series of thiophene-based model compounds, which aims at (i) benchmarking the quantum-chemical calculations against experiments, (ii) identifying the signature of possible structural defects that can appear during the polymerization of PTV's, namely head-to-head and tail-to-tail defects, and (iii) defining a criterion regarding regioregularity

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Design and development of Spell Checker for Tamil language and details of the implementation have been discussed in this paper. Lexicons with morphological and syntactic information are needed for the development of spell checker that can be integrated in word processors, as well as for the development of morphological and syntactic analyzers that can be exploited by more complex natural language processing applications. 1

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Not AvailableIn this study, the effects of spray-dried cluster bean extract (T-1), freeze-dried ethanol extract of coconut husk (T- 2) and control (C) on the shelf life of ready-to-cook shrimp analogue prepared from tilapia surimi at refrigerated temperature (5 ± 1 ◦C) were evaluated. The proximate composition of the shrimp analogues was significantly affected by the incorporation of the additives during the storage. The lower levels of total volatile basic nitrogen values were detected for T-1 and T-2 shrimp analogues. T-2 samples exhibited a lower pH (7.16–6.28) values as days progressed respectively. Elevated levels of thiobarbituric acid reactive substances values were observed in all the treatments including the control. The water holding capacity of T-1 revealed lower values than the control. In texture profile analysis, the highest cohesiveness value was found in T-2 shrimp analogues. The interpretation of sensory attributes i.e. general appearance, colour, odour, texture and overall acceptability of shrimp analogue containing two different additives combined with the storage days was subjected to principal component analysis and most of the data has fallen in component 1. Overall, the work suggests that ethanol extract of coconut husk can be a promising candidate for extending the shelf-life of ready-to-cook surimi-based productsNot Availabl

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Not AvailableThe natural biopolymer, chitin is a structural polysaccharide synthesized by numerous living organisms, which has gained great interest due to its versatile biological activities and distinctive physicochemical properties. In spite of the general occurrence of chitin, so far, the major sources are crab and shrimp shells from marine processing wastes. However, the conventional methods of chitin extraction make use of extremely harsh chemicals such as acids and bases at high temperatures for long durations resulting in final inconsistent physicochemical properties in the final product and environmental pollution. Therefore, a much needed alternative eco-friendly approach would be the use of low-cost commercial enzymes such as papain/pepsin for deproteinization of shell wastes. In the present study, protein hydrolysate was produced through enzymatic hydrolysis of paste shrimp (Acetes spp.) which forms a major group of bycatch in Maharashtra and Gujarat Coasts and the residual shell was utilized for bio-extraction of chitin. This facilitates the complete utilization of Acetes spp. for the production of peptides and chitin, both of which act as bioactive molecules. The extraction conditions, viz., enzyme/substrate ratio (E/S), temperature and time were optimized using Response Surface Methodology for attaining maximum degree of deproteinization. For papain and pepsin hydrolysis, the degree of deproteinization was 96.5% and 89.5% respectively while the optimum extraction conditions obtained for papain were: pH-7.0, E/S (%)-2.1 and temperature-52p C and those for pepsin were: pH-3.1, E/S (%)-1.5 and temperature-37p C. These results suggest that enzymatic deproteinization of the shell residue obtained following protein hydrolysate extraction, could be a prominent eco-friendly strategy to produce chitin.Not Availabl

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Not AvailableProtein hydrolysate powder was prepared from non-penaeid shrimp (Acetes indicus) by enzymatic hydrolysis using Alcalase enzyme. Extraction conditions such as pH (6.5, 7.5 and 8.5), enzyme to substrate ratio (1.0, 1.5 and 2.0) and temperature (40, 50 and 60 °C) were optimized against the degree of hydrolysis using response surface methodology.Not Availabl

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Not AvailableCarotenoproteins from four different shrimp shell wastes Penaeus monodon, Parapenaeopsis stylifera, Metapenaeus affinis and Nematopalemon tenuipes were extracted with the aid of papain enzyme and characterized by their protein, amino acid and carotenoid content of the shell wastes and the antioxidant activities like DPPH, FRAP, ABTS radical scavenging activity and reducing power assay of the carotenoprotein. Higher protein content of 9.8 g 100 g−1 and 9.2 g 100 g−1 was recovered from shell waste of Penaeus monodon and Parapenaeopsis stylifera respectively along with highest carotenoid content of 114 ± 0.02 μg g−1 in Parapenaeopsis stylifera followed by 100.6 ± 0.02 μg g−1 from the shell waste of Metapenaeus affinis. Highest antioxidant activity was found in the carotenoprotein extracted from the shell waste of P. stylifera which suggest that the antioxidant activity of carotenoids followed a concentration dependent pattern. The amino acid profile showed that carotenoprotein is a rich source of essential amino acids such as glutamic acid, aspartic acid, lysine and leucine. Among shell wastes, P.stylifera shell waste was calculated to be superior as it contained higher amount of essential amino acids and exhibited higher antioxidant activity in terms of protein, carotenoid as well as radical scavenging and reducing power and it could serve as a supplementary nutritive feed ingredient in animal diets. This would help in utilization of crustacean (shrimp) shell waste for formulating low cost feed for ornamental fish and also encourage shrimp processing industries to utilize of the same in order to control pollution of land and waterNot Availabl

Nonlinear optical response of a novel polydiacetylene poly(1,4 bis(3-quinolyl)-1,3 butadyne): Role of exciton-phonon interaction

A model incorporating the exciton-phonon interaction for a quantitative description of the third-order nonlinear optical response of a one-dimensional conjugated polymer chain in the vicinity of a one-photon resonance is proposed. This model has been used to describe our observations on the dispersion of the second molecular hyperpolarizability, $\gamma \left( - \omega ; \omega , \omega , - \omega \right)$, of poly(1,4 bis(3-quinolyl))-1,3 butadyne in the spectral range 720–810 nm satisfactorily. The large observed precipitous enhancement close to the absorption tail could not be explained by the essential states models. It is found that the phonon-mediated shift of the exciton resonance is responsible for the large monotonic variation of $\gamma$, whilst the phase space filling effect renders $\gamma$ its self-defocusing character

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Not AvailableFunctional extruded snacks were prepared using paste shrimp powder (Acetes spp.), which is rich in protein. The process variables required for the preparation of extruded snacks was optimized using response surface methodology. Extrusion temperature (130-144 °C), level of Acetes powder (100-200 g kg-1 ) and feed moisture (140-200 g kg-1 ) were selected as design variables, and expansion ratio, porosity, hardness, crispness and thiobarbituric acid reactive substance value were taken as the response variables. Extrusion temperature significantly influenced all the response variables, while Acetes inclusion influenced all variables except porosity. Feed moisture content showed a significant quadratic effect on all responses and an interactive effect on expansion ratio and hardness. Shrimp powder incorporation increased the protein and mineral content of the final product. The extruded snack made with the combination of extrusion temperature 144.59 °C, feed moisture 178.5 g kg-1 and Acetes inclusion level 146.7 g kg-1 was found to be the best one based on sensory evaluation. The study suggests that use of Acetes species for the development of extruded snacks will serve as a means of utilization of Acetes as well as being a rich source of proteins for human consumption, which would otherwise remain unexploited as a by-catch. © 2017 Society of Chemical Industry.Not Availabl