scholarly journals The study of the microstructure of cheese before and after vacuum drying

2020 ◽  
Vol 10 (4) ◽  
pp. 6007-6014
Keyword(s):  
Calcium Phosphate ◽  
Surface Shape ◽  
Vacuum Drying ◽  
Protein Matrix ◽  
Fat Globules ◽  
Before And After ◽  
Calcium Phosphate Particles ◽  
Structure State ◽  
Cheese Microstructure ◽  
Scanning Electron

Scanning electron microscope allowed us to get screens of different cheese microstructure that form a base for further investigation of a cheese structure state before and after the process of drying and for their comparison. Any cheese structure presents a matrix of proteins penetrated with moisture capillaries; fat globules are located both inside the protein matrix and on a cheese surface. Shape of capillaries is either round or oval. Capillaries vary in size and number that has an impact on the cheese pattern which is described by hole and void shapes and order. Electron microscopy was also used for detecting deposition of calcium phosphate. Particles of calcium phosphate changed in size, before drying they were 10–12 µm, and after drying they reached 20–30 µ. These particles concentrate in the dried cheese and agglomerate into larger particles. The most concentrated calcium phosphate proportion was found in pores and micro-voids of the dry cheese. As for mature cheese samples, calcium lactate was established as well.

scholarly journals Redox Mechanism of Azathioprine and Its Interaction with DNA

2021 ◽  
Vol 22 (13) ◽  
pp. 6805
Author(s):  
Mihaela-Cristina Bunea ◽  
Victor-Constantin Diculescu ◽  
Monica Enculescu ◽  
Horia Iovu ◽  
Teodor Adrian Enache
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Structural Changes ◽  
Differential Pulse ◽  
Immunosuppressive Drug ◽  
Redox Mechanism ◽  
Before And After ◽  
Dna Film ◽  
Scanning Electron

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

scholarly journals Cementitious Composites Reinforced with Polypropylene, Nylon and Polyacrylonitile Fibres

2012 ◽  
Vol 730-732 ◽  
pp. 271-276
Author(s):  
H.R. Pakravan ◽  
M. Jamshidi ◽  
M. Latifi ◽  
F. Pacheco-Torgal
Keyword(s):  
Absorption Capacity ◽  
Cement Matrix ◽  
Cementitious Composites ◽  
Scanning Electron Micrographs ◽  
Energy Absorption Capacity ◽  
Cement Ratio ◽  
Pull Out ◽  
Water To Cement Ratio ◽  
Before And After ◽  
Scanning Electron

This paper compares the adhesion strength between three polymeric fibres (polypropylene (PP), nylon66 (N66) and polyacrylonitrile (PAN)) embedded in a cement paste. The specimens were prepared at a water to cement ratio (w/c) of 0.5 and tested after 7, 14 and 28 curing days. It was found that although the adhesion between the polymeric fibres to the cement matrix is an important factor, the energy absorption capacity or energy dissipation ability of the fibres, plays a more important role in the improvement of the cementitious composites fracture toughness. Scanning electron micrographs were used to characterize the fibres surface before and after the Pull-out tests.

scholarly journals USE OF FORMALDEHYDE TO REGULATE DIGESTION OF BARLEY STARCH

1990 ◽  
Vol 70 (2) ◽  
pp. 581-589 ◽  
Author(s):  
T. A. McALLISTER ◽  
K.-J. CHENG ◽  
L. M. RODE ◽  
J. G. BUCHANAN-SMITH
Keyword(s):  
Volatile Fatty Acids ◽  
Rumen Bacteria ◽  
Starch Granules ◽  
Endosperm Cell ◽  
Starch Digestion ◽  
Protein Matrix ◽  
Fermentation Efficiency ◽  
Formaldehyde Treatment ◽  
Scanning Electron ◽  
Anaerobic Media

This study was conducted to determine the effect of formaldehyde treatment of barley on the rate of microbial starch digestion. Ground barley was left untreated (UB) or treated with 0.5% formaldehyde (TB) and incubated in vials with an inoculum consisting of a homogenate of rumen contents and Bryant's anaerobic media (1:1). Separate vials were analyzed for starch, ammonia, pH and volatile fatty acids (VFA) after 0, 4, 8, 12, 18, 24, 36 and 48 h. The digestion of starch was lower (P < 0.05) in TB than in UB between 4 and 24 h. Accumulation of NH3 was lower and pH was higher in TB vials (P < 0.05) than in UB vials. VFA production and fermentation efficiency were lower (P < 0.05) in TB than in UB. Formaldehyde treatment of barley reduced (P < 0.05) the production of propionate and enhanced (P < 0.05) the production of butyrate in comparison with UB. Examination by scanning electron microscopy (SEM) showed that the initial colonization of TB was inhibited in comparison with that of UB. The distinct shape of the endosperm cells of TB (12 h) were readily recognizable, but the endosperm cells of UB (12 h) were not readily distinguishable. SEM of TB (24 h) showed that the protein matrix of the endosperm cell is resistant to microbial digestion. The formaldehyde-induced reduction in starch digestion appears to result from the protein matrix inhibiting the access of bacteria to underlying starch granules. Key words: Starch, rumen bacteria, formaldehyde, barley

scholarly journals Electrodeposited Platinum Iridium Enables Microstimulation With Carbon Fiber Electrodes

2021 ◽  
Vol 3 ◽  
Author(s):  
Elena della Valle ◽  
Beomseo Koo ◽  
Paras R. Patel ◽  
Quentin Whitsitt ◽  
Erin K. Purcell ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Cross Sections ◽  
Minimal Scarring ◽  
Pulse Testing ◽  
Implant Tests ◽  
Before And After ◽  
Voltage Transients ◽  
Scanning Electron

Ultrasmall microelectrode arrays have the potential to improve the spatial resolution of microstimulation. Carbon fiber (CF) microelectrodes with cross-sections of less than 8 μm have been demonstrated to penetrate cortical tissue and evoke minimal scarring in chronic implant tests. In this study, we investigate the stability and performance of neural stimulation electrodes comprised of electrodeposited platinum-iridium (PtIr) on carbon fibers. We conducted pulse testing and characterized charge injection in vitro and recorded voltage transients in vitro and in vivo. Standard electrochemical measurements (impedance spectroscopy and cyclic voltammetry) and visual inspection (scanning electron microscopy) were used to assess changes due to pulsing. Similar to other studies, the application of pulses caused a decrease in impedance and a reduction in voltage transients, but analysis of the impedance data suggests that these changes are due to surface modification and not permanent changes to the electrode. Comparison of scanning electron microscope images before and after pulse testing confirmed electrode stability.

scholarly journals Sedimentation Study of Biphasic Calcium Phosphate Particles

2007 ◽  
pp. 365-368
Author(s):  
Ahmed Fatimi ◽  
Jean Francois Tassin ◽  
Monique Aselo V. Axelos ◽  
Pierre Weiss
Keyword(s):  
Calcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Calcium Phosphate Particles

Synthesis and Film Investigation of Titania

2013 ◽  
Vol 832 ◽  
pp. 128-131
Author(s):  
Sharipah Nadzirah ◽  
Uda Hashim
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Titanium Dioxide ◽  
Sol Gel ◽  
Titanium Butoxide ◽  
Before And After ◽  
Scanning Electron ◽  
Spin Coater

Titania or titanium dioxide (TiO2) thin film has been synthesized via sol-gel method with monoethanolamine (MEA) as a catalyst. The mixing of titanium butoxide as a precursor, ethanol as a solvent and MEA were stirred using magnetic stirrer under ambient temperature [. The TiO2solution prepared then was deposited on SiO2substrates using spin-coater and the coated films were annealed at 600°C. Finally, both before and after annealed TiO2thin films were characterized using Field Emission Scanning Electron Microscopy (FESEM). The obtained results show the different TiO2particles formation before and after annealed.

Cavitation Erosion of HVOF Coatings

1996 ◽  
Author(s):  
R. Schwetzke ◽  
H. Kreye
Keyword(s):  
Erosion Rate ◽  
Cavitation Erosion ◽  
Metallic Alloys ◽  
Erosion Mechanism ◽  
Hvof Coatings ◽  
Coating Composition ◽  
Before And After ◽  
Series Of Experiments ◽  
The Individual ◽  
Scanning Electron

Abstract The proposed paper reports a series of experiments to investigate the cavitation erosion mechanism of HVOF coatings. Vibratory cavitation erosion tests according to ASTM G 32 have been carried out with several HVOF coatings including cermets, oxides and metallic alloys. The steady state erosion rate for each coating was determined and the effect of coating composition and microstructure on the erosion rate was investigated. The morphology and microstructure of the various coatings before and after cavitation testing were analyzed by means of light optical and scanning electron microscopy in order to study the erosion mechanism. The results demonstrate that HVOF coatings of NiCrFeBSi, WC-17Co, Cr3C2-25NiCr and Cr2O3 can exhibit a rather high resistance against cavitation erosion and should be considered for application as a protective surface layer against cavitation. Furthermore, it is shown that cavitation testing can provide a useful tool to study and characterize the bond strength between individual splats as well as the brittleness of the individual phases present in the coating.

Microstructural and Fractographic Analysis of CuAlNi Shape Memory Alloy before and after Heat Treatment

2020 ◽  
Vol 405 ◽  
pp. 100-106
Author(s):  
Ivana Ivanić ◽  
Mirko Gojić ◽  
Stjepan Kožuh ◽  
Borut Kosec
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Fracture Surface ◽  
Shape Memory ◽  
Fractographic Analysis ◽  
Before And After ◽  
Different Temperatures ◽  
The Difference ◽  
Type Of Fracture ◽  
Scanning Electron

The paper presents comparison of microstructure and fracture surface morphology of the CuAlNi shape memory alloy (SMA) after different heat treatment procedures. The investigation was performed on samples in as-cast state and heat treated states (solution annealing at temperatures of 850 °C / 60’ / H2O and 920 °C / 60’ / H2O along with tempering at two different temperature 150 °C / 60’ / H2O and 300 °C / 60’ / H2O). The microstructure of the samples was examined by optical (OM) and scanning electron microscope (SEM) equipped with device for EDS analysis. The obtained fracture surfaces were examined by SEM. Optical and scanning electron microscopy showed martensitic microstructure in all investigated samples. However, the fractographic analysis of samples after tensile testing reveals significant changes in fracture mechanism. In both solution annealed states the results shows transgranular type of fracture, but after tempering at two different temperatures the difference is obvious. After tempering at 150 °C, along with transgranular type of fracture appear some areas with intergranular type of fracture. After tempering at 300 °C, fracture surface reveals completely intergranular type of fracture.

Sign in / Sign up

Export Citation Format

Share Document