1,721,046 research outputs found
Fluctuation in physicochemical properties of chitins extracted from different body parts of honeybee
No full textWOS: 000361184900002PubMed: 26256318It is well known that physicochemical properties of chitin are related with the extraction method. Recently, it was revealed that some physicochemical properties of chitin are also related with taxonomical relationship. For the first time in this study, it was tested how these properties of chitin are affected by different body parts of one organism. The chitins were extracted from five different body parts (head, thorax, abdomen, legs and wings) of honeybee. These chitins were physicochemically characterized and differences among these body parts were identified. Highest chitin content was observed in legs (13.25%) while the lowest from thorax (6.79%). The surface morphologies of the isolated chitin structures from five different body parts were analyzed with SEM, as a result, five different types of surface morphologies were recorded. However, three different types of surface morphologies were observed only in abdomen. Maximum degradation temperatures (DTG(max)) of thorax, abdomen, legs and wings were recorded between 359 and 367 degrees C while DTG(max) value of head chitin was found as 308 degrees C. (C) 2015 Elsevier Ltd. All rights reserved
Changes in physicochemical properties of chitin at developmental stages (larvae, pupa and adult) of Vespa crabro (wasp)
No full textWOS: 000375109200008PubMed: 27106152It is already known that chitin in a single organism can exhibit huge differences depending on the functions it serves in different body parts, but the alterations in the characteristics of chitin in course of developmental stages of an organism still remain unknown. This study presents findings on how chitin matrix is changing physicochemically through discrete morphological stages - larva, pupa and adult - of an insect (Vespa crabro). Chitin content of the organisms were found to increase gradually as the organism grew; 2.1, 6.2 and 10.3%, with a dramatic increase in chitin deposition (nearly 3 folds) during the instar from larva to pupa. Enzymatic digestion test demonstrated that chitin isolates were close to pure. Chitin isolates were also subjected to thermal pyrolysis and no variations were observed in the thermal stability of the samples. However, it was observed that surface characteristics of chitin changed greatly as the insect grew
Surface morphology of chitin highly related with the isolated body part of butterfly (Argynnis pandora)
No full textWOS: 000367408300054PubMed: 26277749This study was conducted to understand the differences in the physicochemical properties of chitin samples isolated from the wings and the other body parts except the wings (OBP) of a butterfly species (Argynnis pandora). The same isolation method was used for obtaining chitin specimens from both types of body parts. The chitin content of the wings (22%) was recorded as being much higher than the OBP (8%). The extracted chitin samples were characterized via FT-IR, TGA, XRD, SEM, and elemental analysis techniques. Results of these characterizations revealed that the chitins from both structures (wings and OBP) were very similar, except for their surface morphologies. SEM results demonstrated one type of surface morphology for the wings and four different surface morphologies for the OBP. Therefore, it can be hypothesized that the surface morphology of the chitin is highly related with the body part. (C) 2015 Elsevier B.V. All rights reserved
Newly isolated sporopollenin microcages from Platanus orientalis pollens as a vehicle for controlled drug delivery
No full textWOS: 000403381200030PubMed: 28532028Sporopollenin microcages were produced from the pollens of Platanus orientalis. Paracetamol was loaded into the microcages. Pollen, sporopollenin, paracetamol and paracetamol-loaded sporopollenin microcages were characterized with FT-IR, TGA and SEM. The analytical analyses demonstrated that sporopollenin microcages were structurally intact, highly reticulated and thermally stable. The loading efficiency of the sporopollenin microcages was found to be 8.2% using the passive loading technique and 23.7% via evaporating loading technique. In vitro release and kinetics studies were performed to test the suitability of sporopollenin microcages for loading. These studies revealed that sporopollenin from P. orientalis can be suggested as a suitable carrier for drug loading and controlled release studies. (C) 2017 Published by Elsevier B.V.Scientific and Technological Research Council of Turkey - Graduate Scholarship Programme for International Students [TUBITAK 2215]The first author would like to thank The Scientific and Technological Research Council of Turkey for supporting him during this study under the program number TUBITAK 2215 - Graduate Scholarship Programme for International Students
Determination of bovine serum albumin adsorption capacity of newly obtained cellulose extracted from glycyrrhiza glabra (Licorice)
Full text linkWOS: 000428843400032Exploration of biodegradable and renewable composites ingredients is of great importance. Up to now, roots extract of Glycyrrhiza glabra has been used for different medicinal purposes but remaining cellulose-rich residues have not been evaluated for isolation of any green materials like cellulose. Here in this study, cellulose was successfully isolated from the roots of G. glabra by using conventional cellulose extraction method. The obtained product was characterized using FT-IR, XRD, and SEM. FT-IR and XRD analyses confirmed the identity of the product. The crystallinity index of cellulose isolates was calculated from XRD data as 70%. The cellulose content of the roots on dry basis was recorded as 48.5%. Three types of surface morphologies were observed: smooth non-porous surface, surface with fibril bundles, and porous surface having thin cellulose fibrils. In addition, bovine serum albumin (BSA) adsorption capacity of G. glabra cellulose was determined and compared with that of commercial cellulose. Newly obtained cellulose from the roots of G. glabra exhibited a higher affinity for BSA protein at neutral pH. (c) 2016 Wiley Periodicals, Inc
Current advancements in chitosan-based film production for food technology; A review
No full textWOS: 000452346100101PubMed: 30340012Chitosan is obtained from chitin, which could be considered to be the most abundant polymer after cellulose. Owing to these properties, chitosan alone or chitosan-based composite film production is attaining huge attention in terms of applications from researchers and industrialists coming from divergent fields. To enhance the biological (mainly antimicrobial and antioxidant) and physiological (mainly mechanical, thermal and barrier) attributes of the chitosan-based films, a vast medley of plant extracts and supporting polymers has been blended into chitosan films. Considering the up to date literature reports based on chitosan film production and applications, it can be stated that still, the research ratio is low in this field. Chitosan blend/composite films with specific properties (superhydrophobicity, excellent mechanical strength, acceptable barrier properties) can be produced only for specific applications in food technology. In the current review, we tried to summarize the advancements made in the last 5-7 years in the field of chitosan film technology for its application in the food industry
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Novel, multifunctional mucilage composite films incorporated with cellulose nanofibers
No full textWOS: 000455346800003In the current study, mucilage composite films were produced by incorporating the cellulose nanofibrils (CNF) at different concentrations i.e., 3 and 6% to chia mucilage matrix by solution casting method. To evaluate the effect of CNF incorporation into mucilage matrix, the obtained composite films were characterized extensively using both physicochemical and biological tools. FT-IR spectra confirmed the composite formation by broader -OH bond peaks than in the spectrum of mucilage control film and shift of C=O stretching vibration peak lower wave number and widen in the mucilage films including cellulose nanofibers. Cellulose nanofibers did not reveal a significant effect on the thermal properties of the all three composite films and dynamic thermogravimetric values were recorded as similar or equal to 287 degrees C. Atomic force microscopy revealed a homogenous distribution of cellulose nanofibers across the mucilage matrix. Dynamic mechanical analysis revealed that the inclusion of cellulose nanofibers in mucilage film led to an enhancement of the tensile modulus as well as the tensile strength, but without reducing the strain at break of the film. Cellulose nanofibers incorporation significantly enhanced the hydrophobic properties of the composite films. The cytotoxicity assay results demonstrated mucilage composite films were nontoxic and have anticancer properties; reducing the viability of cancer cell line by similar or equal to 20% and retaining the cell viability of epithelial cell line by similar or equal to 90%. Cellulose nanofibers incorporation also significantly enhanced the antioxidant and antimicrobial attributes of the mucilage composite films. Overall, the current study provided an idea regarding the biocompatible, non-toxic, highly antioxidative and antimicrobial biodegradable nature of mucilage-CNF composite films, making it a suitable candidate for food and pharmaceutical industry
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
