Laser Scanning Microscopy Method Research Articles

Microstructure of confectionery masses revealed by cryo-planing

Here we present a novel, combined cryo-scanning electron microscopy (cryo-SEM) and confocal laser scanning microscopy (CLSM) method for imaging of chocolate confectionery product microstructures of several millimeters down to about 100 nm. The SEM part of the method is based on cryo-fixation, cryo-polishing, and scanning electron microscopy, at low vacuum and low temperature using the backscattered electron signal. Starting with cryo-fixation of the chocolate sample in a desired state (cooled, ambient, or melted), the sample is cryo-planed in a cryo-ultramicrotome. Once a polished cut is obtained, the sample is analyzed using a cryo-SEM technique, with the unusual combination of low temperature and low vacuum settings, without heavy metal coating. Imaging is done based on material density contrast. Elemental composition of particles is recorded by energy dispersive x-ray spectroscopy (EDS). The combination of imaging contrast and EDS allows identification and measurement of the four main constituents of chocolate (cocoa solids, fat, sugar, and milk solids). Finally, the same cryo-polished sample sections of solid chocolate products are analyzed using a CLSM imaging technique to reveal complementary microstructural details. An obvious application of the method could be the visualization and quantitative analysis of the size, shape, and composition of chocolate confectionery products.

Block copolymer micelles stabilized Pickering emulsions in templating ultralight conducting PEDOT: PSS elastomeric aerogels

Amphiphilic copolymers poly(N-(2-methacryloylxy) ethyl pyrrolidone)-block-poly(2-(perfluorooctyl) ethyl methacrylate) (PNMPm-b-PFMAn) with similar m/n of about 10 preferred to form spherical micelles in water regardless of the molecular weight. These PNMPm-b-PFMAn micelles as Pickering emulsifiers commonly favored the formation of O/W Pickering emulsions in the cyclohexane/water systems, and the corresponding interfacial structures were characterized by the confocal laser scanning microscopy (CLSM) method. Moreover, high internal phase Pickering emulsions (HIPPEs) were formed at high volume ratio of oil/water (VO/VW), which were excellent templates in generating structurally well-defined 3D porous PEDOT:PSS aerogels with low density and high conductivity. It was noticed that the HIPPE-templated PEDOT:PSS aerogels were mainly composed of hierarchically connected nano-/micro-level fibers, which were significantly different from the randomly intertangled lamellar micro-belts of PEDOT:PSS aerogels prepared by the hydrogel method under the same conditions. In addition, the HIPPE-templated stretchable and compressible PEDOT:PSS aerogels showed wide strain-invariant resistance (SIR) range and remarkable cycling stability, which were far superior to the hydrogel ones.

Morphology and Emulsification of Poly(N-2-(methacryloyloxy) ethyl pyrrolidone)-b-poly(benzyl methacrylate) Assemblies by Polymerization-Induced Self-Assembly.

In this work, a series of amphiphilic diblock copolymers poly(N-2-(methacryloyloxy) ethyl pyrrolidone)-b-poly(benzyl methacrylate) (PNMP m -b-PBzMA n ) were developed by the dispersion polymerization method in ethanol. The polymerization-induced self-assembly (PISA) behaviors were studied systematically, and a comprehensive structure-property relationship was also established. Two distinct PISA tendencies were observed, which was mainly depended on the polymerization degree m of PNMP segment. When m is small such as 39 and 55, morphological transitions from spherical to vesicle-like assemblies via wormlike ones upon increasing n commonly happen regardless of the solid content. Alternatively, spherical assemblies became the sole morphology for PNMP64-b-PBzMA n block copolymers because of the excellent solvophilicity of the PNMP64 segment. Attributing to the amphiphilicity of PNMP m -b-PBzMA n block copolymers, PNMP m -b-PBzMA n assemblies by PISA are a type of excellent Pickering emulsifiers. These assemblies prefer to stabilize O/W Pickering emulsions as confirmed by the confocal laser scanning microscopy method, and the effects of polymerization degree of PBzMA segment or morphologies of PNMP m -b-PBzMA n assemblies are finite.

Monitoring sodium caseinate and whey protein isolate interaction with mild preheat treatment using ultrasound spectroscopy and confocal laser scanning microscopy

Ultrasound spectroscopy and confocal laser scanning microscopy (CLSM) methods were developed to visualize the interaction between sodium caseinate (SC) and whey protein isolate (WPI) with a mild preheat treatment (57°C, 10 min) followed by adding glucono-δ-lactone (GDL). Ultrasonic velocity changes during incubation at 25°C after adding GDL for four kinds of mixtures (no-treated SC plus no-treated WPI, preheated SC plus no-treated WPI, no-treated SC plus preheated WPI and preheated SC plus preheated WPI) were monitored. The results reveal that the mild preheating treatment of the proteins affected the timing of the increase in compressibility of each system. CLSM observation with individualized dyes which have different maxima of excitation and emission wavelengths, showed the preheated SC plus no-treated WPI mixture had a slightly coarse structure and the highest correlation coefficient, suggesting the highest colocalization of the SC and WPI among the four kinds of mixed-protein systems. Furthermore, the scanning electron microscopy (SEM) observation suggests that there are some differences among the gels, namely, preheated WPI leads to the formation of developed three-dimensional gel networks with filamentous structures, whereas SC promotes the formation of cluster-like crowded networks composed of more fine aggregated particles instead of developed filamentous structures. These results demonstrated that although SC is known as a heat-stable protein, pretreated SC could lead to an increase of the collaboration with WPI in the presence of GDL. This finding anticipated the possibility creating a food material with another texture using a milk-protein mixed system.

Superhydrophobic, antibacterial, and EMI shielding properties of Ag/PDMS-coated cotton fabrics

In this study, three functionalities of superhydrophobicity, antibacterial activity and electromagnetic interference (EMI) shielding of cotton fabrics coated with Ag/PDMS were studied, and the role of coating composition was discussed. Special attention was paid to understanding the relationships between the surface roughness of coated fibres with the developed superhydrophobicity and antibacterial activity. The superhydrophobicity of fabrics was analysed based on water contact angle (WCA) and contact angle hysteresis (CAH) values while the antibacterial activity was tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. It was found that the surface roughness on fibres, which changed by altering the concentrations of Ag NPs (0.2–4 g/L) and PDMS (20 and 40 g/L), affected the obtained superhydrophobicity. The most superhydrophobic fabric (WCA 171°) was coated with a formulation containing Ag NPs (2 g/L), and PDMS (20 g/L), and had the highest surface roughness. Increasing the ingredients’ concentrations, however, deteriorated the optimum roughness as measured using a 3D Surface Laser Scanning Microscopy method. The coated fabrics showed efficacy against both types of bacteria, and it was confirmed that the Ag NPs content was the key factor in determining the antibacterial performance. Moreover, testing the EMI shielding performance of fabrics demonstrated that increasing the concentrations of Ag NPs and PDMS both enhanced the reflection coefficient (R) of fabrics against incident X-band electromagnetic (EM) wave by around >500%, which was due to the deposition of a higher amount of Ag NPs on fabrics. The superhydrophobicity of fabrics was durable after 1000 abrasion cycles, and the fabrics retained their antibacterial activity even after numerous washings.Graphical

Experimental Study on Single Fiber Tensile Properties of Sisal Fibers Using a Digital Image Correlation Method as a Strain Measurement

ABSTRACT The development of natural fibers in engineering applications requires an accurate measurement of their dimensional characteristics and mechanical properties. Fiber cross-sectional area (CSA) obtained from lateral dimensional measurements should consider the specific cross-sectional shape (CSS) of the fibers and their wide lengthwise variations. In this study, the dimensional measurements of water-retted and unretted sisal fibers were conducted by laser scanning microscopy (LSM) and calculation-based methods. Single fiber tensile tests were performed using the digital image correlation (DIC) method. Results show that the diameters of water-retted and unretted fibers measured by LSM were 233 ± 45 µm and 236 ± 42 µm, respectively. The diameters of water-retted and unretted fibers obtained by calculation were 192 ± 17 µm and 178 ± 20 µm, respectively. The tensile strengths of water-retted and unretted fibers were 679 ± 118 MPa and 718 ± 106 MPa, respectively. The strain at failure and elastic modulus of water-retted and unretted fibers were 2.0 ± 0.6% and 34 ± 8 GPa, as well as 1.5 ± 0.2% and 48 ± 6 GPa, respectively. Water retting seems to predominantly influence the strain at failure and elastic modulus of sisal fibers, as confirmed by the ANOVA analysis.

Fabricating switchable Pickering emulsions by dynamic covalent copolymer amphiphiles

In this work, amphiphilic copolymers D-An based on the dynamic imine bonds were generated in-situ in the aqueous solutions by two water-soluble precursors, the random copolymer poly(N-(2-methacryloylxyethyl)-random-poly(4-(formaldehyde) phenyl methacrylate) (PNMP83-co-PBFMA4, Precursor D) and alkylamines (Precursor An, n represents the carbon number in the alkyl chain that is ranging from 4 to 10). Amphiphiles D-An formed micelles spontaneously in the aqueous solutions, which were studied by the surface tension and cryogen-transmission electron microscopy (cryo-TEM) measurements. Moreover, the CO2/N2 responsive micellization of D-An due to the reversible formation and breaking of the dynamic imine bond (-CH=N-) was confirmed by the nuclear magnetic resonance (NMR) measurements. Accordingly, the emulsification of dynamic covalent amphiphilic copolymers D-An was studied in detail. O/W Pickering emulsions with excellent stability were commonly generated by employing D-An as emulsifiers regardless of n and the nature of oil employed, which was significantly different from the weak emulsification of either precursor D or precursor An. The synergistic emulsification of D-An monomers and micelles was proved to be the major cause as evidenced by the confocal laser scanning microscopy (CLSM) method. Noticeably, the abundant alkylamines were also advantageous in stabilizing emulsions. Attributing to the stimuli-responses of amphiphiles D-An to CO2/N2, the stability of Pickering emulsions could be reversibly controlled by CO2/N2 as well.

On the quantitative assessment of corrosion damages of aluminum at the early stages using confocal laser scanning microscopy

Despite being widely used in such industries as chemical, aviation and food ones, aluminum and its alloys are known to be prone to localized corrosion, and this remains a problem to be solved, especially when it comes to pitting corrosion. Therefore, there is a necessity to detect traces of corrosion at the earliest stages and to quantify the extent of corrosion damage. The simplest solution for assessing the overall corrosion rate is to use the gravimetric method, which, however, does not provide information for assessment of localized corrosion. This paper is devoted to the consideration of the possibilities of using the method of confocal laser scanning microscopy (CLSM) for assessing corrosion resistance using high-purity aluminum. The CLSM method, due to its high resolution (especially along the vertical axis), enables to obtain quantitative data on the volume of corroded metal, determine the depth of corrosion damage including building their profilograms, and analyze the morphology of the surface damaged by corrosion. Owing to the high sensitivity of the CLSM method, corrosion losses were detected within 21 days, contrary to the standard gravimetric method, which failed to determine the loss of metal even after 160 days of corrosion testing.

Dysfunction of the meibomian glands in patients with diabetes mellitus

T he prevalence of diabetes mellitus has increased in recent decades. The most common ophthalmic manifestations of diabetes mellitus are retinopathy, epitheliopathies, corneal erosion and dry eye syndrome, the symptoms of which are more pronounced than in people without diabetes. The meibomian glands, which are the producer of various lipids, participate in the formation of the lipid layer of the tear film, which prevents the evaporation of the water-mucin phase and ensures the preservation of homeostasis of the ocular surface. Meibum is a lipid-rich secret produced by fully differentiated meibocytes. Impaired insulin secretion, insulin resistance, absolute insulin deficiency, as well as hyperglycemia, potentiate the development of oxidative stress and a cascade of metabolic changes, leading to a change in the anatomical and functional state of the meibomian glands, which affects the qualitative and quantitative secretion. Cytological abnormalities, as well as the structure of the excretory ducts of the meibomian glands in patients with long-term diabetes mellitus, were established using the method of laser scanning microscopy. Using the method of mass spectrometry, it is possible to determine the patterns of changes in the chemical composition of meibum in patients with diabetes mellitus. The data obtained can become one of the criteria for predicting the course, reflect the degree of compensation and / or progression of diabetes mellitus.

Phase-resolved visualization of radio-frequency standing waves in superconducting spiral resonator for metamaterial applications

Superconducting microcircuits and metamaterials are promising candidates for use in new generation cryogenic electronics. Their functionality is largely justified by the macroscopic distribution of electromagnetic fields in arranged unit cells, rather than by the microscopic properties of composite materials. We present a new method for visualizing the spatial structure of penetrating microwaves with microscopic resolution in planar superconducting macroscopic resonators as the most important circuit-forming elements of modern microelectronics. This method uses a low-temperature laser scanning microscope that examines the phase (i.e., direction) and amplitude of local radio-frequency currents versus the two-dimensional coordinates of the superconducting resonant structure under test. Phase-sensitive contrast is achieved by synchronizing the intensity-modulated laser radiation with the resonant harmonics of the microwave signal passing through the sample. In this case, the laser-beam-induced loss in the illuminated area will strongly depend on the local phase difference between the RF carrier signal and the spatially temporal structure of the focused laser oscillation. This approach eliminates the hardware limitations of the existing technique of radio-frequency microscopy and brings the phase-sensitive demodulation mode to the level necessary for studying the physics of superconducting metamaterials. The advantage of the presented method over the previous method of RF laser scanning micros-copy is demonstrated by the example of the formation of standing waves in a spiral superconducting Archimedean resonator up to the 38th eigenmode resonance.

Artocarpus integrifolia seed lectin enhances membrane damage, oxidative stress and biofilm inhibition activity of silver nanoparticles against Staphylococcus aureus

Functionalizing the nanoparticles to target the bacteria surface is an effective approach to curb drug resistance pathogens. The present study describes the synthesis of N-myristoyltaurine capped silver nanoparticles (AgNPs) and functionalization of AgNPs with jacalin (JAgNPs), a lectin from the seeds of Artocarpus integrifolia . JAgNPs has fourfold lower minimum inhibitory concentration than AgNPs and kills the S. aureus in less than 30 min through inducing oxidative stress and membrane damage. JAgNPs (31.25 µM) was found to have excellent biofilm inhibitory activity at lower concentration than AgNPs (62.5 µM). This was judged by crystal violet assay, light microscopy imaging and confocal laser scanning microscopy (CLSM) method. CLSM analysis reveals that JAgNPs is highly effective as compared to AgNPs in reducing the bio-volume and average biofilm thickness to 18.3 ± 2.5 µm 3 /µm 2 and 14.0 ± 2.6 µm, respectively. Scanning electron microscopy (SEM) study reveals that JAgNPs prevents the colony formation and inhibited exopolysaccharide synthesis, thereby reducing the formation of biofilm. At minimum biofilm inhibitory concentrations, SEM and double staining technique using CLSM provides evidence that cells are intact and live, suggesting that NPs exhibit true biofilm activity. The findings indicate that jacalin functionalization may offer a unique way to use nanosilver at lower concentrations for treating infection associated with S. aureus biofilm. • Jacalin functionalized AgNPs kills S. aureus in less than 30 min. • NPs exert antibacterial activity through inducing oxidative stress and membrane damage. • Jacalin-AgNPs exhibit antibiofilm activity at 0.5X MIC. • NPs inhibits exopolysaccharide biosynthesis.

Dendrite growth in nickel-based superalloy with in-situ observation by high temperature confocal laser scanning microscopy and numerical simulation

Dendrite growth of nickel-based superalloy was investigated by using high temperature confocal laser scanning microscopy (HT-CLSM) and numerical simulation method. The influence of cooling rate on the evolution of dendrite was discussed through in-situ observation experiments and simulation cases. The results indicate that secondaryand tertiary dendrites grow luxuriantly at the higher cooling rate and primary dendrite present well growth tendency at the lower cooling rate. The variation of secondary dendrite arm spacing (SDAS) with cooling rate was also analyzed, and the results show that SDAS decrease exponentially with the increasing of cooling rate, which is helpful for designing process parameters to obtain desirable dendrites.

Rheological properties and fractal-rheology analysis of peanut protein isolate suspension

This study focuses on the non-linear rheological property and microstructure of peanut protein isolate (PPI) aggregation suspension. The impact of higher harmonics (I3 and I5) on fundamental stress wave during large amplitude oscillatory shear test was studied. Rheological test show that storage modulus G′ and loss modulus G″ increased with increasing PPI concentration. The non-linear viscoelastic properties of PPI suspension with different concentration were investigated. Using confocal laser-scanning microscopy method, this research explored the microstructure of PPI suspension as well as the fractal dimensions. The new critical strain indirect method combined with Wu-Morbidelli model to calculate the fractal dimension (2.9225) is very close to the actual fractal dimension (2.9206). Fourier Transform Rheology was adopted to get the new critical strain for fractal dimension calculation, which was proved to be feasible. Keywords: peanut protein isolate suspension, rheological property, microstructure, fractal analysis DOI: 10.25165/j.ijabe.20201306.5717 Citation: Bi C H, Chi S Y, Hua Z, Li D, Huang Z G, Liu Y. Rheological properties and fractal-rheology analysis of peanut protein isolate suspension. Int J Agric & Biol Eng, 2020; 13(6): 220–226.

Dynameric Collagen Self-Healing Membranes with High Mechanical Strength for Effective Cell Growth Applications.

The fabrication of biocompatible adaptive materials with high stiffness and self-healing properties for medical applications is a challenging endeavor. Collagen is a major extracellular matrix component acting as a substrate for cell adhesion and migration. Dynamers are constitutional polymers whose monomeric components are linked through reversible bonds, able to modify their constitution through reversible exchange of their components. In the current work, we demonstrate that the rational combination of collagen and dynameric networks connected with reversible covalent imine bonds is a very important and previously unreported strategy to provide biocompatible membranes with self-healing ability and excellent mechanical strength. The key challenge in the construction of such membranes is the required adaptive interaction between collagen chains and the dynamic cross-linkers, preventing the formation of defects. For example, by varying structure and molecular lengths of the dynamers, the tensile strength of the dynameric membranes reach over 80 MPa, more than 400 % higher than that observed for the reference collagen membrane, and the highest value for break strain found, was 19 %. The self-healing properties were observed when reconnecting two membrane pieces or even from crushed status of the membranes. Moreover, both MTT assay and confocal laser scanning microscopy method demonstrated the good biocompatibility of the collagen membranes, leaving more than 90 % viability for NIH 3T3 cells after 24 h co-culture.

A membrane protein insertion complex

The present study examined the long-standing concept that changes in hippocampal circuitry contribute to age-related learning impairment. Individual differences in spatial learning were documented in young and aged Long–Evans rats by using a hippocampal-dependent version of the Morris water maze. Postmortem analysis used a confocal laser-scanning microscopy method to quantify changes in immunofluorescence staining for the presynaptic vesicle glycoprotein, synaptophysin (SYN), in the principal relays of hippocampal circuitry. Comparisons based on chronological age alone failed to reveal a reliable difference in the intensity of SYN staining in any region that was examined. In contrast, aged subjects with spatial learning deficits displayed significant reductions in SYN immunoreactivity in CA3 lacunosum-moleculare (LM) relative to either young controls or age-matched rats with preserved learning. SYN intensity values for the latter groups were indistinguishable. In addition, individual differences in spatial learning capacity among the aged rats correlated with levels of SYN staining selectively in three regions: outer and middle portions of the dentate gyrus molecular layer and CA3-LM. The cross-sectional area of SYN labeling, by comparison, was not reliably affected in relation cognitive status. These findings are the first to demonstrate that a circuit-specific pattern of variability in the connectional organization of the hippocampus is coupled to individual differences in the cognitive outcome of normal aging. The regional specificity of these effects suggests that a decline in the fidelity of input to the hippocampus from the entorhinal cortex may play a critical role.

Investigation on the formation mechanism of non-metallic inclusions in high-aluminum and titanium-alloyed Ni-based superalloy

The effect of adding sequence of active elements (Al and Ti), and crucible materials (Al2O3 and MgO) on the composition, size, morphology and number of inclusions formed in FGH4096 superalloy were investigated to enhance a better understanding of the inclusion formation mechanism in high Al–Ti-alloyed superalloy. The results show that the addition sequence of Al and Ti, and crucible materials are two main factors that control the oxide inclusions. Inclusions were small spherical TiOx oxides when Ti was added before Al and they were transferred to Al2O3 after the addition of Al, and the fraction of inclusions smaller than 1 μm was the largest. However, inclusions were irregular or polygonal Al2O3 when Al and Ti were added simultaneously or Al was added before Ti. Furthermore, Al2O3 inclusions were smaller when Al and Ti were added simultaneously rather than Al addition before Ti. When the crucible was MgO, inclusions were transformed to MgO–Al2O3. The optimized process is to add Ti before Al, which can help form small sized oxides. Moreover, in-situ confocal laser scanning microscopy method was used to confirm the results. Inclusions are MgO–Al2O3, suggesting that MgO–Al2O3 is the thermodynamically stable inclusion rather than TiOx containing inclusions.

TiO2/P(AM-co-AMPS) monolith prepared by CO2-in-water HIPEs and its potential application in wastewater treatment

Removing dyes and antibiotics from wastewater remains the current requirement for a global health problem. The ionic macroporous adsorbent is an efficient solution to this problem. Herein, a novel sulfonated TiO2/poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) [TiO2/P(AM-co-AMPS)] macroporous composite monolith was first prepared by copolymerization of AM and AMPS in mTiO2-costabilized CO2-in-water Pickering high internal phase emulsions (HIPEs). The composite monoliths were characterized using XRD, SEM, confocal laser scanning microscopy, EDS mapping, FTIR, TGA, and mercury injection methods. The mechanical properties of the TiO2/P(AM-co-AMPS) HIPE were also evaluated. The void diameter could be adjusted by changing the density of carbon dioxide and the amount of mTiO2. The equilibrium swelling ratios of TiO2/P(AM-co-AMPS) with different contents of crosslinking agent of 2, 5, and 10 wt% (AM+AMPS) were 93, 37, and 19 g/g, respectively. TiO2/P(AM-co-AMPS) was used to remove methylene blue (MB) and tetracycline (TC) for evaluating the adsorptive properties of the composite monoliths. Results indicated that the main adsorption driving force was the electrostatic attraction between −SO3− and MB/TC. Adsorption experiments were conducted using a batch technique. The adsorption capacities of TiO2/P(AM-co-AMPS) for MB and TC were 1660 and 1128 mg/g in a wide pH range of 3–10. The equilibrium saturation point could be reached after 90 min for MB and 360 min for TC. Thereafter, the removal of MB and TC by gravity-driven separation was presented. The breakthrough curve and reuse evaluation for the removal of MB/TC were also studied in detail.

Nano-graphene oxide with antisense vicR RNA reduced exopolysaccharide synthesis and biofilm aggregation for Streptococcus mutans.

Streptococcus mutans (S. mutans) has been proved to crucial cariogenic pathogens. Antisense vicR RNA reduced the transcription of virulence genes and lead to a reduction in biofilm formation. In the current study, a graphene-oxide plasmid transformation system was developed using interacted GO-polyethylenimine (PEI) complexes loaded with antisense vicR-expressing plasmid (GO-PEI-ASvicR). The particle size distribution and zeta potential of the GO-PEI-based ASvicR were evaluated. Quantitative real-time PCR assays were used to investigate the expression of S. mutans virulence genes. The exopolysaccharide (EPS) production in biofilm were evaluated by confocal laser scanning microscopy and anthrone method. We showed that GO-PEI could efficiently deliver the ASvicR-expressing plasmid into S. mutans cells and support excellent transcripts of ASvicR. Furthermore, GO-PEI-ASvicR significantly reduced virulent-associated gene expressions, suppressed biofilm aggregation and inhibited EPS accumulation. Our reports demonstrated that preserving nano-graphene oxide with antisense vicR RNA will be a more effective strategy for dental caries management.

Comparative Evaluation of Antifungal Activity of Octenidine: An In Vitro Confocal Laser Study

The aim of this study was to evaluate the antifungal efficacy of a novel endodontic irrigant octenidine against conventional irrigants sodium hypochlorite and EDTA on Candida albicans growth in the young and old population by calculating the number of colonies formed and by qualitative identification of dead/viable fungi by Confocal laser scanning microscopy (CLSM) method. The total number of samples used in the study was eighty samples after decoronation of the crown portion the middle third of root canal. Each group was subdivided into four subgroups with various irrigation protocols: (A) 17% EDTA + 5.25% NaOCl, (B) 100% Octenisept, (C) 17% EDTA + 5.25% NaOCl + 1% clotrimazole, and (D) phosphate buffer saline. After completion of irrigation ATCC samples (90028) of C. albicans were inoculated with 5 mL of peptone water each and incubated at 37°C for 72 hours to attain the turbidity corresponding to 0.5 McFarland standards CFU. Eight samples were analyzed for the formation of candidal colonies, and two samples for the assessment of viability of Candida by confocal laser scanning microscope in each subgroup. Comparison of antifungal efficacy of endodontic irrigants employed in the young and old populations revealed a significant reduction in the mean values of CFU and the mean values of percentage of non-viable microorganism by CLSM method. A positive relationship was revealed in the younger population which had a better antifungal efficacy than the older population in all the irrigant subgroups evaluated in the study. All the endodontic irrigants employed in our study had a good antifungal efficacy against Candida albicans. Octenisept had a maximum antifungal efficacy, while phosphate saline showed the least efficacy in both age groups, which was quantitatively evaluated by CFU method, and the same was confirmed through qualitative evaluation by CLSM method. Candida albicans plays a major role in the establishment and pathogenesis of failed root canal treatment. Age-related changes alter the adhesion potential of dentin, in turn influence the outcome of endodontic therapy. Octenidine, a novel antifungal agent, can be substituted over the conventionally used EDTA and NaOCl with less adverse effects.

Rheological properties and fractal-rheology analysis of peanut protein isolate suspension

This study focuses on the non-linear rheological property and microstructure of peanut protein isolate (PPI) aggregation suspension. The impact of higher harmonics (I3 and I5) on fundamental stress wave during large amplitude oscillatory shear test was studied. Rheological test show that storage modulus G′ and loss modulus G″ increased with increasing PPI concentration. The non-linear viscoelastic properties of PPI suspension with different concentration were investigated. Using confocal laser-scanning microscopy method, this research explored the microstructure of PPI suspension as well as the fractal dimensions. The new critical strain indirect method combined with Wu-Morbidelli model to calculate the fractal dimension (2.9225) is very close to the actual fractal dimension (2.9206). Fourier Transform Rheology was adopted to get the new critical strain for fractal dimension calculation, which was proved to be feasible. Keywords: peanut protein isolate suspension, rheological property, microstructure, fractal analysis DOI: 10.25165/j.ijabe.20201306.5717 Citation: Bi C H, Chi S Y, Hua Z, Li D, Huang Z G, Liu Y. Rheological properties and fractal-rheology analysis of peanut protein isolate suspension. Int J Agric & Biol Eng, 2020; 13(6): 220–226.