Tailoring Multi-Level Structural and Practical Features of Gelatin Films by Varying Konjac Glucomannan Content and Drying Temperature

Here, we tailored the multi-level structural and practical (mechanical/hydrophilic) features of gelatin films by varying the konjac glucomannan (KGM) content and the film-forming temperatures (25 and 40 °C). The addition of KGM apparently improved the mechanical properties and properly increased the hydrophilicity. With the lower temperature (25 °C), the increase in KGM reduced the gelatin crystallites of films, with detectable KGM–gelatin interactions, nanostructures, and micron-scale cracks. These structural features, with increased KGM and negligibly-occurred derivatizations, caused initially an insignificant decrease and then an increase in the strength, with a generally-increased elongation. The higher temperature (40 °C) could reduce the strength and slightly increase the elongation, related to the reduced crystallites of especially gelatin. With this higher temperature, the increase in KGM concurrently increased the strength and the elongation, mainly associated with the increased KGM and crystallites. Additionally, the increase in KGM made the film more hydrophilic; the multi-scale structural changes of films did not dominantly affect the changing trend of hydrophilicity.

Download Full-text

Microstructure and Mechanical/Hydrophilic Features of Agar-Based Films Incorporated with Konjac Glucomannan

Polymers ◽

10.3390/polym11121952 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1952 ◽

Cited By ~ 2

Author(s):

Dongling Qiao ◽

Wenyao Tu ◽

Lei Zhong ◽

Zhong Wang ◽

Binjia Zhang ◽

...

Keyword(s):

Tensile Strength ◽

Chemical Structure ◽

Structural Changes ◽

Konjac Glucomannan ◽

Preparation Temperature ◽

Phase Separations ◽

Characterization Methods ◽

Multi Scale ◽

Changing Trend ◽

Scale Structures

Different characterization methods spanning length scales from molecular to micron scale were applied to inspect the microstructures and mechanical/hydrophilic features of agar/konjac glucomannan (KGM) films prepared under different drying temperatures (40 and 60 °C). Note that the lower preparation temperature (40 °C) could increase the strength and elongation of agar/KGM films at high KGM levels (18:82 wt/wt KGM-agar, or higher). This was related to the variations in the film multi-scale structures with the increment of KGM content: the reduced crystallinity, the increased perfection of nanoscale orders at some KGM amounts, and the negligibly-changed morphology and molecular chemical structure under 40 °C preparation temperature. These structural changes initially decreased the film tensile strength, and subsequently increased the film strength and elongation with increasing KGM content. Moreover, under the higher drying temperature (60 °C), the increased KGM content could concurrently reduce the strength and elongation for the films, associated with probable phase separations on nano and smaller scales. In addition, the increased KGM amount tended to make the film more hydrophilic, whereas the changes in the film structures did not dominantly affect the changing trend of hydrophilicity.

Download Full-text

Effect of Isothermal Ageing on Damping Capacity of Cu-20.4Al-8.7Mn

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.268-270.312 ◽

2012 ◽

Vol 268-270 ◽

pp. 312-315

Author(s):

Gang Ling Hao ◽

Qiao Ping Xu ◽

Wei Guo Wang

Keyword(s):

Internal Friction ◽

Room Temperature ◽

Ageing Temperature ◽

Damping Capacity ◽

Temperature Ageing ◽

Changing Trend ◽

Higher Temperature ◽

Friction Measurements ◽

Isothermal Ageing ◽

Lower Temperature

The effect of ageing temperature on damping capacity of the Cu-20.4Al-8.7Mn alloy at room temperature was investigated by internal friction measurements. The results indicated that damping capacity of the alloy exhibits a non-monotonous changing trend with ageing temperature. Ageing at lower temperature of less than 150oC, damping capacity rapidly increses even up to maximum of 0.01 with the increasing ageing temperature, the reason of which should relate with the increased amount of twin boundaries and phase interfaces between martensites due to the thinning and splitting of martensitic plates, whereas when the ageing temperature exceeds 150oC, the damping capacity trends to steeply decrease as the ageing temperature increases until close to a constant in last corresponding to the ageing at higher temperature due to the occurrence and complete finish of transformation of martensites to austenites.

Download Full-text

Skin and dry adhesion

10.1093/oso/9780199674923.003.0022 ◽

2018 ◽

Author(s):

Changhyun Pang ◽

Chanseok Lee ◽

Hoon Eui Jeong ◽

Kahp-Yang Suh

Keyword(s):

Material Properties ◽

Structural Features ◽

Mechanical Interlocking ◽

Multi Scale ◽

Skin Patch ◽

Reversible Adhesion ◽

Dry Adhesion ◽

Close Observation ◽

Dry Adhesives ◽

Shed Light

Close observation of various attachment systems in animal skins has revealed various exquisite multi-scale architectures for essential functions such as locomotion, crawling, mating, and protection from predators. Some of these adhesion systems of geckos and beetles have unique structural features (e.g. high-aspect ratio, tilted angle, and hierarchical nanostructure), resulting in mechanical interlocking mediated by van der Waals forces or liquid secretion (capillary force). In this chapter, we present an overview of recent advances in bio-inspired, artificial dry adhesives, and biomimetics in the context of nanofabrication and material properties. In addition, relevant bio-inspired structural materials, devices (clean transportation device, interlocker, biomedical skin patch, and flexible strain-gauge sensor) and microrobots are briefly introduced, which would shed light on future smart, directional, and reversible adhesion systems.

Download Full-text

Sprouting of Sorghum (Sorghum bicolor [L.] Moench): Effect of Drying Treatment on Protein and Starch Features

Foods ◽

10.3390/foods10020407 ◽

2021 ◽

Vol 10 (2) ◽

pp. 407 ◽

Cited By ~ 1

Author(s):

Mia Marchini ◽

Alessandra Marti ◽

Claudia Folli ◽

Barbara Prandi ◽

Tommaso Ganino ◽

...

Keyword(s):

Food Production ◽

Cost Effective ◽

High Exposure ◽

Effective Technology ◽

Drying Treatment ◽

Higher Temperature ◽

Lower Temperature ◽

The One ◽

Drying Conditions ◽

Sorghum Bicolor L

The nutritional and physicochemical properties of sorghum proteins and starch make the use of this cereal for food production challenging. Sprouting is a cost-effective technology to improve the nutritional and functional profile of grains. Two drying treatments were used after sorghum sprouting to investigate whether the drying phase could improve the protein and starch functionalities. Results showed that the drying treatment at lower temperature/longer time (40 °C for 12 h) extended the enzymatic activity that started during sprouting compared to the one performed at higher temperature/shorter time (50 °C for 6 h). An increased protein hydrolysis and water- and oil-holding capacity were found in the flour obtained by the former treatment. Higher protein matrix hydrolysis caused high exposure of starch to enzymes, thus increasing its digestibility, while worsening the technological functionality. Overall, modulating drying conditions could represent a further way, in addition to sprouting, to improve sorghum flour’s nutritional profile.

Download Full-text

Interaction of Lactoferrin with Unsaturated Fatty Acids: In Vitro and In Vivo Study of Human Lactoferrin/Oleic Acid Complex Cytotoxicity

Materials ◽

10.3390/ma14071602 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1602

Author(s):

Anna Elizarova ◽

Alexey Sokolov ◽

Valeria Kostevich ◽

Ekaterina Kisseleva ◽

Evgeny Zelenskiy ◽

...

Keyword(s):

Oleic Acid ◽

Structural Changes ◽

Unsaturated Fatty Acids ◽

Structural Features ◽

Control Group ◽

Acid Complex ◽

Hepatoma 22A ◽

Constitutive Parameters

As shown recently, oleic acid (OA) in complex with lactoferrin (LF) causes the death of cancer cells, but no mechanism(s) of that toxicity have been disclosed. In this study, constitutive parameters of the antitumor effect of LF/OA complex were explored. Complex LF/OA was prepared by titrating recombinant human LF with OA. Spectral analysis was used to assess possible structural changes of LF within its complex with OA. Structural features of apo-LF did not change within the complex LF:OA = 1:8, which was toxic for hepatoma 22a cells. Cytotoxicity of the complex LF:OA = 1:8 was tested in cultured hepatoma 22a cells and in fresh erythrocytes. Its anticancer activity was tested in mice carrying hepatoma 22a. In mice injected daily with LF-8OA, the same tumor grew significantly slower. In 20% of animals, the tumors completely resolved. LF alone was less efficient, i.e., the tumor growth index was 0.14 for LF-8OA and 0.63 for LF as compared with 1.0 in the control animals. The results of testing from 48 days after the tumor inoculation showed that the survival rate among LF-8OA-treated animals was 70%, contrary to 0% rate in the control group and among the LF-treated mice. Our data allow us to regard the complex of LF and OA as a promising tool for cancer treatment.

Download Full-text

Lattice disorder effect on magnetic ordering of iron arsenides

Scientific Reports ◽

10.1038/s41598-019-56301-5 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Athena S. Sefat ◽

Xiaoping P. Wang ◽

Yaohua Liu ◽

Qiang Zou ◽

Mimgming Fu ◽

...

Keyword(s):

Magnetic Coupling ◽

Magnetic Ordering ◽

Structural Features ◽

Lattice Parameter ◽

Chemical Compositions ◽

Lattice Disorder ◽

Local Lattice ◽

Higher Temperature ◽

Disordered Crystal ◽

Planar Strain

AbstractThis study investigates magnetic ordering temperature in nano- and mesoscale structural features in an iron arsenide. Although magnetic ground states in quantum materials can be theoretically predicted from known crystal structures and chemical compositions, the ordering temperature is harder to pinpoint due to potential local lattice variations that calculations may not account for. In this work we find surprisingly that a locally disordered material can exhibit a significantly larger Néel temperature (TN) than an ordered material of precisely the same chemical stoichiometry. Here, a EuFe2As2 crystal, which is a ‘122’ parent of iron arsenide superconductors, is found through synthesis to have ordering below TN = 195 K (for the locally disordered crystal) or TN = 175 K (for the ordered crystal). In the higher TN crystals, there are shorter planar Fe-Fe bonds [2.7692(2) Å vs. 2.7745(3) Å], a randomized in-plane defect structure, and diffuse scattering along the [00 L] crystallographic direction that manifests as a rather broad specific heat peak. For the lower TN crystals, the a-lattice parameter is larger and the in-plane microscopic structure shows defect ordering along the antiphase boundaries, giving a larger TN and a higher superconducting temperature (Tc) upon the application of pressure. First-principles calculations find a strong interaction between c-axis strain and interlayer magnetic coupling, but little impact of planar strain on the magnetic order. Neutron single-crystal diffraction shows that the low-temperature magnetic phase transition due to localized Eu moments is not lattice or disorder sensitive, unlike the higher-temperature Fe sublattice ordering. This study demonstrates a higher magnetic ordering point arising from local disorder in 122.

Download Full-text

MICROSTRUCTURAL EVOLUTION OF Al-Cu-Mg-Ag ALLOY WITH TRACE Zr ADDITION DURING TWO-STEP HOMOGENIZATION

International Journal of Modern Physics B ◽

10.1142/s0217979209060142 ◽

2009 ◽

Vol 23 (06n07) ◽

pp. 855-862 ◽

Cited By ~ 3

Author(s):

FEIYUE MA ◽

ZHIYI LIU

Keyword(s):

Melting Point ◽

Grain Boundaries ◽

Microstructural Evolution ◽

Cast Alloy ◽

Scanning Calorimetry ◽

Zr Addition ◽

Homogenization Time ◽

The Matrix ◽

Higher Temperature ◽

Lower Temperature

The microstructural evolution in an Al - Cu - Mg - Ag alloy with trace Zr addition during homogenization treatment was characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS). It was shown that the low-melting-point phase segregating toward grain boundaries is Al 2 Cu , with a melting point of 523.52°C. A two-step homogenization process was employed to optimize the microstructure of the as-cast alloy, during which the alloy was first homogenized at a lower temperature, then at a higher temperature. After homogenized at 420°C for 6 h, Al 3 Zr particles were finely formed in the matrix. After that, when the alloy was homogenized at an elevated temperature for a longer time, i.e., 515°C for 24 h, most of the precipates at the grain boundaries were removed. Furthermore, the dispersive Al 3 Zr precipitates were retained, without coarsening greatly in the final homogenization step. A kinetics model is employed to predict the optimal homogenization time at a given temperature theoretically, and it confirms the result in present study, which is 420°C/6h+515°C/24h.

Download Full-text

Research on the Static Recrystallization and Precipitation Behaviors of a V-N Microalloyed Steel

Advances in Materials Science and Engineering ◽

10.1155/2013/390285 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Baochun Zhao ◽

Tan Zhao ◽

Guiyan Li ◽

Qiang Lu

Keyword(s):

Static Recrystallization ◽

Microalloyed Steel ◽

Time Interval ◽

Main Role ◽

Recrystallization Process ◽

Compression Tests ◽

Double Compression ◽

Higher Temperature ◽

Lower Temperature ◽

Temperature Strain

Double compression tests were performed on a Gleeble-3800 thermomechanical simulator to study the softening behaviors of deformed austenite in a V-N microalloyed steel. The static recrystallization volume fractions were calculated by stress offset method, and the kinetic model of static recrystallization was constructed. The effects of temperature, strain, and time interval on the softening behaviors were analyzed, and the interactions between precipitation and recrystallization were discussed. The results show that the softening behaviors of the deformed austenite at lower temperature or higher temperature are markedly different. At the temperature of 850°C or 800°C, pinning effects of the precipitates play the main role, and the recrystallization process is inhibited, which leads to the formation of plateaus in the softening curves. An increase in strain promotes the precipitation and recrystallization processes while reduces the inhibition effect of precipitation on recrystallization as well.

Download Full-text

Effects of Sr Addition on Mechanical Properties and Microstructure of Mg-6Al Magnesium Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.686.120 ◽

2011 ◽

Vol 686 ◽

pp. 120-124

Author(s):

Jin Ping Fan ◽

She Bin Wang ◽

Bing She Xu

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Magnesium Alloy ◽

Strengthening Mechanism ◽

Microstructure And Mechanical Properties ◽

Higher Temperature ◽

Lower Temperature

The effects of Sr addition on the mechanical properties and microstructure of Mg-6Al mag- nesium alloy both at 25 °C and at 175 °C were investigated by means of OM, SEM and EDS and XRD. Upon the Sr addition of 2%, the tensile strength was increased by 7.2% to 184.4MPa at 25 °C, while it was increased by 30% to 155.4MPa at 175 °C. The strengthening mechanism of Mg-6Al-xSr at lower temperature (25 °C) was different from that at higher temperature (175°C). The results show that the addition of strontium effectively improved the microstructure and mechanical properties of magnesium alloy.

Download Full-text

Post-operative rehabilitation and nutrition in osteoarthritis

F1000Research ◽

10.12688/f1000research.4178.3 ◽

2016 ◽

Vol 3 ◽

pp. 116 ◽

Cited By ~ 4

Author(s):

Giuseppe Musumeci ◽

Ali Mobasheri ◽

Francesca Maria Trovato ◽

Marta Anna Szychlinska ◽

Rosa Imbesi ◽

...

Keyword(s):

Articular Cartilage ◽

Physical Exercise ◽

Structural Changes ◽

Exercise Program ◽

Structural Features ◽

Synovial Joint ◽

Comprehensive Overview ◽

Postoperative Rehabilitation ◽

Keywords Osteoarthritis ◽

Rehabilitation Exercise

Osteoarthritis (OA) is a degenerative process involving the progressive loss of articular cartilage, synovial inflammation and structural changes in subchondral bone that lead to loss of synovial joint structural features and functionality of articular cartilage. OA represents one of the most common causes of physical disability in the world. Different OA treatments are usually considered in relation to the stage of the disease. In the early stages, it is possible to recommend physical activity programs that can maintain joint health and keep the patient mobile, as recommended by OA Research Society International (OARSI) and European League Against Rheumatism (EULAR). In the most severe and advanced cases of OA, surgical intervention is necessary. After, in early postoperative stages, it is essential to include a rehabilitation exercise program in order to restore the full function of the involved joint. Physical therapy is crucial for the success of any surgical procedure and can promote recovery of muscle strength, range of motion, coordinated walking, proprioception and mitigate joint pain. Furthermore, after discharge from the hospital, patients should continue the rehabilitation exercise program at home associated to an appropriate diet. In this review, we analyze manuscripts from the most recent literature and provide a balanced and comprehensive overview of the latest developments on the effect of physical exercise on postoperative rehabilitation in OA. The literature search was conducted using PubMed, Scopus, Web of Science and Google Scholar, using the keywords ‘osteoarthritis’, ‘rehabilitation’, ‘exercise’ and ‘nutrition’. The available data suggest that physical exercise is an effective, economical and accessible to everyone practice, and it is one of the most important components of postoperative rehabilitation for OA.

Download Full-text