Tag: tapping mode

Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer

In the article «Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer» Daniel Garcia-Garcia , José Enrique Crespo-Amorós, Francisco Parres and María Dolores Samper describe how they studied the effect of ultraviolet radiation on styrene-ethylene-butadiene-styrene (SEBS) at different exposure times in order to obtain a better understanding of the mechanism of ageing.*

The results obtained for the SEBS, in relation to the duration of exposure, showed superficial changes that cause a decrease in the surface energy (s) and, therefore, a decrease in surface roughness. This led to a reduction in mechanical performance, decreasing the tensile strength by about 50% for exposure times of around 200 hours.*

NanoWorld Pointprobe® NCH AFM probes were used in the Atomic force microscopy (AFM) applied to determine the surface topography and roughness of the aged samples.

Figure 4 from «Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer» by Daniel Garcia-Garcia et al.: Atomic force microscopy (AFM) surface of SEBS: (a) without exposure (T0), (b) UV exposure T2, (c) UV exposure T7 and (d) UV exposure T9.


Figure 4 from «Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer» by Daniel Garcia-Garcia et al.:
Atomic force microscopy (AFM) surface of SEBS: (a) without exposure (T0), (b) UV exposure T2, (c) UV exposure T7 and (d) UV exposure T9.

*Daniel Garcia-Garcia , José Enrique Crespo-Amorós, Francisco Parres and María Dolores Samper
Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer
Polymers 2020, 12, 862
DOI: https://doi.org/10.3390/polym12040862

Please follow this external link to read the full article: https://www.mdpi.com/2073-4360/12/4/862

Open Access : The article “Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer» byDaniel Garcia-Garcia , José Enrique Crespo-Amorós, Francisco Parres and María Dolores Samper is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Pectin Interaction with Immune Receptors is Modulated by Ripening Process in Papayas

Dietary fibers have been shown to exert immune effects via interaction with pattern recognition receptors (PRR) such as toll-like receptors (TLR) and nucleotide-binding oligomerization domain (NOD)-like receptors. Pectin is a dietary fiber that interacts with PRR depending on its chemical structure. Papaya pectin retains different chemical structures at different ripening stages. How this influences PRR signalling is unknown.*

The aim of the article “Pectin Interaction with Immune Receptors is Modulated by Ripening Process in Papayas” by Samira B. R. Prado, Martin Beukema, Eva Jermendi, Henk A. Schols, Paul de Vos and João Paulo Fabi was to determine how ripening influences pectin structures and their ability to interact with TLR2, 3, 4, 5 and 9, and NOD1 and 2.*

Papaya ripening is an enzymatic, biochemically driven process that occurs over a short period of time (five days) and involves the mobilization of pectin and the alteration of its chemical composition.

The authors evaluated the interaction of the water-soluble fractions rich in pectin extracted from unripe to ripe papayas. The pectin extracted from ripe papayas activated all the TLR and, to a lesser extent, the NOD receptors. The pectin extracted from unripe papayas also activated TLR2, 4 and 5 but inhibited the activation of TLR3 and 9.*

During papaya ripening, profound changes in pectin structures lead to differences in the biological effects. The data presented in the paper show that papaya pectin extracted from fruit pulp at different ripening points differently interacted with PRR in a ripening-dependent way. The longer chains of HG from unripe papayas pectin, which were less methyl-esterified, inhibited the activation of TLR3 and 9 and activated TLR2 and 4, in contrast to the ripe papaya’s pectin, which have smaller HG chains with medium methyl esterification thus activating TLR2, 3, 4, 5 and 9.*

This variation may represent new biological features of papaya pectin structures in addition to anticancer activities, possibly creating new and cost-effective approaches to extracting papaya pectin with desirable structural and biological features.*

These findings might lead to selection of ripening stages for tailored modulation of PRR to support or attenuate immunity in consumers.*

The changes in Molecular weight ( Mw ) can also be visualized by Atomic Force Microscopy (see Fig. 1C in the paper.)

The AFM images presented in the paper were acquired in tapping mode using an NanoWorld Pointprobe® NCHR AFM probe with a typical spring constant of 42 N/m and typically 320 kHz resonance frequency. The scan speed and scanning resolution were 0.5 Hz and 512 × 512 points, respectively.*

Figure 1 C from “Pectin Interaction with Immune Receptors is Modulated by Ripening Process in Papayas” by Samira B. R. Prado et al. 2020:
(C) Representative topographical AFM images of Un-1-WSF and R-2-WSF. White arrow indicates linear structures, black arrow aggregates and grey arrow the smaller structure from the R-2-WSF. Un-1-WSF: unripe – papaya from 1st day after harvest – water-soluble fraction; Un-2-WSF: unripe – papaya from 2nd day after harvest – water-soluble fraction; I-WSF: intermediate ripening time point – papaya from 3rd day after harvest – water-soluble fraction; R-1-WSF: ripe – papaya from 4th day after harvest – water-soluble fraction; R-2-WSF: ripe – papaya from 5th day after harvest – water-soluble fraction. Please have a look at the full article for the full figure.

*Samira B. R. Prado, Martin Beukema, Eva Jermendi, Henk A. Schols, Paul de Vos and João Paulo Fabi
Pectin Interaction with Immune Receptors is Modulated by Ripening Process in Papayas
Nature Scientific Reports volume 10, Article number: 1690 (2020)
DOI: https://doi.org/10.1038/s41598-020-58311-0

Please follow this external link to read the full article https://rdcu.be/b3Fnb .

Open Access The article “ Pectin Interaction with Immune Receptors is Modulated by Ripening Process in Papayas “ by Samira B. R. Prado, Martin Beukema, Eva Jermendi, Henk A. Schols, Paul de Vos and João Paulo Fabi is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum

Yersinia enterocolitica is a gram-negative bacillus shaped bacterium that leads to a zootonic disease called yersiniosis. The infection is demonstrated as mesenteric adenitis, acute diarrhea, terminal ileitis, and pseudoappendicitis. Rarely, it can even result in sepsis. According to the 2017 report of the European Food Safety Authority (EFSA) and European Centre for Disease Prevention and Control (ECDC), Y. enterocolitica has been realized as the third most common foodborne-zoonotic disease after campylobacteriosis and salmonellosis in the European Union.*

Several studies suggested that the bacterium cannot survive after a proper pasteurization process, although contrary findings were also reported. The quick and accurate detection of the bacterium from food products or the body fluids of infected individuals is, therefore, important.*

Biosensors offer strong alternatives to the already existing detection techniques for rapid and sensitive quantification of Y. enterocolitica.*

In their paper “Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum” Sumeyra Savas and Zeynep Altintas describe a novel immunosensor approach using graphene quantum dots (GQDs) as enzyme mimics in an electrochemical sensor set up to provide an efficient diagnostic method for Y. enterecolitica.*

The developed method can be used for any pathogenic bacteria detection for clinical and food samples without pre-sample treatment. Offering a very rapid, specific and sensitive detection with a label-free system, the GQD-based immunosensor can be coupled with many electrochemical biosensors.*

The bare gold, GQD-laminated, and antibody-immobilized sensor surfaces were characterized by atomic force microscopy (AFM) using NanoWorld Pointprobe® NCLR AFM probes.*

Figure 4 from “Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum“ by S. Savas and Z. Altintas:
AFM analysis of bare (A), GQD-laminated (B), and antibody-immobilized (C) sensor surfaces.

*Sumeyra Savas and Zeynep Altintas
Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum
Materials 2019, 12(13), 2189
DOI: https://doi.org/10.3390/ma12132189

Please follow this external link to read the full article: https://www.mdpi.com/1996-1944/12/13/2189

Open Access The article “Graphene Quantum Dots as Nanozymes for Electrochemical Sensing of Yersinia enterocolitica in Milk and Human Serum “ by Sumeyra Savas and Zeynep Altintas is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.