Mechanistic study on the effects of “blanching + additives” pretreatment on microwave freeze-drying of longan

This paper presents a novel biological specimen analysis system by hybrid microscope, which is combined optical and environmental-scanning electron microscope (E-SEM) based on nanorobotic manipulation system. As previous works, we present single cell analysis by E-SEM nanorobotic manipulation system. It can be realized that the nano-scale manipulation and evaluation by nano-tools using the nano-scale image of E-SEM. The E-SEM provides us the high resolution image of specimen with water containing condition by specially built detector and temperature controlling stage. However the E-SEM image, especially SEM image, is surface image, hence it is impossible to obtain the inner structural imaging which is important for biological analysis. In this work, we combine optical microscope (OM) and E-SEM to realize biological specimen analysis by optical microscope image including fluorescent imaging, and nano-scale manipulation by E-SEM imaging. We observe C. elegans as biological specimen analysis, because it is one of important model organism for various diseases analysis. The viability analysis has been done from the eGFP fluorescent intensity of C. elegans under E-SEM observation and electron beam irradiation. This system will be applied as future nano-surgery system based on nanomanipulation system for biological specimen.

A BSTRACTInterspecific fungal interactions are important ecological processes, whereas their physiological mechanisms are little understood. The aim of this work was to study how activity of fungal extracellular laccase was changed across mycelia during interactions between white- and brown-rot basidiomycetes from different wood decay stages. Qualitative assay of eight species interacting with each other in all combinations showed four spatial patterns of laccase activity: (I) laccase activity present both in contact zone and mycelium, (II) laccase activity only in contact zone, (III) laccase activity in mycelium but not in contact zone, (IV) no laccase activity. Presence of laccase activity only in the contact zone was more frequent than expected from random samples associated with mycelia that replaced other ones. On the other hand, the presence of laccase activity in the mycelium but not in the contact zone was only attributed to fungal species that were replaced by their antagonists. After one month, laccase activity was distributed over mycelia more homogeneously than after 6 days of interactions. In interacting mycelia, laccase activity was higher than in control and increasing with time. Saprotrophic fungi from late successional stages of wood decay generally had higher laccase activity than early succession saprotrophic and pathogenic fungi. The qualitative assays were confirmed by quantitative assay of total laccase activity. Significance of the results in antagonistic fungal interactions as well as in the processes of hyphal tip growth and mycelium senescence is discussed.

This paper presents a novel biological specimen analysis system by hybrid microscope, which is combined optical microscope and environmental-scanning electron microscope (E-SEM) based on nanorobotic manipulation system. The E-SEM provides us the high resolution image of specimen with water containing condition by specially built detector and temperature controlling stage. However the E-SEM image, especially SEM image, is surface image, hence it is impossible to obtain the inner structural imaging which is important for biological analysis. In this work, we combine the optical microscope (OM) and E-SEM to realize biological specimen analysis by optical microscope image including fluorescent imaging, and nano-scale manipulation by E-SEM imaging. In this paper, we observe C. elegans as biological specimen analysis. The viability analysis has been done from the eGFP fluorescent intensity of C. elegans under E-SEM observation and electron beam irradiation. This system will be applied as future nano-surgery system based on nanomanipulation system for biological specimen.

Scanning electron microscopy of stems and roots of vine plants affected by Petri disease demonstrated that the obstruction of xylem vessels and reduction in the flow of xylem sap, two symptoms of this disease, were mainly caused by tyloses forming in the vessels, and, to a lesser extent, by the accumulation of aggregates. Fungal hyphae were also found in the xylem. These hyphae propagated via the xylem and invaded other vessels or adjacent parenchymatic cells through the pit. Analysis of lignin peroxidase, manganese peroxidase and laccase activity (all of which are involved in lignin degradation) in different fungi isolated from Petri-disease-infected grapevines found that Phaeoacremonium aleophilum expressed low specific activity for manganese peroxidase and high specific activity for both lignin peroxidase and laccase, while Phaeomoniella chlamydospora showed no activity for any of these enzymes. All these enzyme activities were inhibited by the phenolic compounds in grapevine: p-coumaric acid, catechin, caffeic acid and tannins. The phenolic compounds also had a direct effect on fungal growth and sporulation. When SO4 vines affected by Petri disease were treated with Brotomax (a product that stimulates synthesis of phenolic compounds) plants showed an increase in growth and a reduction in Petri-disease symptoms. Any new shoots and roots formed after Brotomax treatment did not show any sign of obstruction or tyloses formation.

Gelatin is a biopolymer that can be generated from partially hydrolysis of collagen tissue. Extraction of gelatin consists of pretreatment and thermal extraction steps. Pretreatment process used sodium hydroxide to remove non collagen protein in matrix sample, sulfuric acid to demineralize, and citric acid to hydrolyse. The aim of this research was to study the effect of variation in concentrations of citric acid used in hydrolysis process on the gel strength and protein profile of gelatin products extracted from broiler chicken skin. The variation of the concentration citric acid used was 0.7 % (GA); 1.5% (GB); and 3.0% b/v (GC) respectively. The gel strength was measured using CT3 Texture Analyzer and protein profile of gelatin product was analyzed by SDS-PAGE method. The result showed that variation in concentration of citric acid used in the pretreatment process affected the gel strength and protein profile of gelatin product. Increasing the concentration of citric acid used in pretreatment process decreased the gel strength and molecular weight of gelatin product. Gel strength of each gelatin product was 265.81 g bloom for GA ; 196.05 g bloom for GB (1.5%), and 35.32 g bloom for GC (3.0 %) respectively. The electropherogram of both GA (0.7%) and GB (1.5%) revealed similar pattern of protein bands but the thickness of each bands was different. On the other hands, GC (3.0%) did not show any protein bands on the eletropherogram. The best gelatin product obtained in this experiment was found by using 0.7 % b/v citric acid (GA) in the pretreatment process. The gelatin product (GA) had characteristics as follows: yield 15.73%; moisture 7.30%; ash 0.51%; protein content 97.95%; fat content 0.62%; gel strength 265. 81 g bloom and thicker protein bands than others.

A novel nanotool exchanger system is proposed based on Environmental Scanning Electron Microscope (E-SEM) nanorobotic manipulation system. We proposed to use the E-SEM nanomanipulation system for the analysis of biological specimen using various “nanotools” to realize flexible and complex nano-scale stiffness measurement, adhesion force measurement, cutting, and injection. The E-SEM can use to observe the biological samples in nano-scale and real-time without any drying or dyeing processes. As previous works, we applied the system to manipulate biological specimens, such as Caenorhabditis elegans (C. elegans) and yeast cells. To maintain the livable condition of biological cells, it is important to reduce the exchange time of the nanotools. This is also important to improve the efficiency of biological specimen analysis using various nanotools without break the chamber pressure. This paper presents a novel nanotool exchanger system for exchanging different nanotools within the ESEM chamber. Through the nanotool exchanger system, the following advantages are mainly obtained, 1) it is not needed to open the sample chamber to exchange the nanotools and to evacuate the sample chamber pressure again, 2) it is not needed to operate manually to exchange nanotools, 3) it is possible to recover the nanotools by exchanging new one, 4) it is possible to use different tools continuously. Firstly, the design and fabrication are presented for the proposed nanotool adaptor, nanotool attachment and nanotool holder. Finally, we demonstrate to exchange the different nanotools based on E-SEM nanomanipulation system.

The aim of the study was to investigate the effects of several decalcifying agents used as irrigant solutions in endodontic treatment on collagen and mineral components of dentin. Coronal dentin discs from five caries-free human third molars with a smear layer were treated for one minute with a chelating solution (1% Ethylenediaminetetraacetic acid (EDTA), 10% EDTA, 17% EDTA, 10% citric acid). Mineralization degree (Ca/N and P/N atomic ratios, IR Iapatite/Iamide II and I1410(carbonate)/I554(phosphate) spectroscopic ratios) and possible collagen rearrangements (collagen infrared (IR) amide II e III shifts) were evaluated by environmental scanning electron microscopy (ESEM)/energy dispersive X-ray spectroscopy (EDX) and IR spectroscopy before and after treatment (T0) and after ageing (T24h and T2m) in simulated body fluid (SBF). At T0, analysis showed that the highest demineralizing effect was achieved using a 10% citric acid solution and 10% EDTA, while the smallest effect was observed when using 17% EDTA. No significant collagen modifications were detected upon treatment with 1% EDTA, while subtle changes were observed after the other treatments. At T24h or T2m, analyses showed the highest remineralization values for 1% EDTA and the lowest for 10% citric acid, mainly at T2m. The samples treated with 17% EDTA showed slight collagen rearrangements upon remineralization. In conclusion, the highest demineralizing effect was observed for 10% EDTA and 10% citric acid. Collagen rearrangement was found for all the treatments except for 1% EDTA. The highest remineralization capability in SBF values was recorded for 1% EDTA and the lowest for 10% citric acid. A slight collagen rearrangement upon remineralization was still present in 17% EDTA-treated samples. Clinical use as a chelating agent in the endodontic therapy of citric acid and concentrated EDTA solutions should be reconsidered.

The laccase activity induced by copper ions in Trametes versicolor by two inducers was studied and the aims were to show that it is possible to obtain a high laccase activity in almost 12 of the enzymes product using a basic culture medium but different copper concentration. Laccase was inducted by 2,5-xylidine and copper sulfate. Semi-purification of the crude laccase was carried out through precipitation and the column separation with NaCl gradient. In order to apply in an effluent treatment, laccase was immobilized on different vitroceramics supports, pyrolytic graphite and also on a carbon fiber electrode as biosensor. The maximum laccase activity was 40,774.0 U L-1 at the 12th day. The best support for immobilization was pyrolytic graphite (glutaraldehyde treated-94% efficiency). Total phenol removal in Kraft E1 effluent was 19% for immobilized pyrolytic graphite with the mediator present. The biosensor prepared with this material showed a good linear response to catechol. The optimization of laccase activity induction through the combination of 2,5-xylidine and cooper sulfate was obtained and led to its use in environmental remediation. Key words: Trametes versicolor, laccase induction, semi-purification, immobilization, effluent treatment.

Erosion incidence is increasing and its control is still a challenge in clinical practice. This study evaluated 4% TiF4-gel effects on eroded human dentin subjected to in situ erosive/abrasive episodes. Seventy-two previously eroded dentin slabs (0.05 M citric acid, pH 2.3, 20 min) were allocated to 6 groups (n=12) according to the treatment to be performed during the in situ phase and number of erosive/abrasive cycles, as follows: 4% TiF4-gel applied once (TiF41), twice (TiF42) or three times (TiF43) followed by 1, 2 and 3 erosive/abrasive cycles, respectively. Gel was applied before the beginning of the next cycle. Control groups were subjected to 1 (C1), 2 (C2) and 3 (C3) erosive/abrasive cycles only. A seventh group (n=12) comprised in vitro uneroded samples (UN) subjected to 3 erosive/abrasive cycles. Each cycle corresponded to 2 days of erosive (citric acid 0.5%, pH 2.6, 6x/day) and abrasive (electric toothbrush, 10 s/sample, 1 x/day) challenges. Samples were evaluated under profilometry and environmental scanning electron microscopy (ESEM). Atomic force microscopy images (AFM) were also made (n=3). Repeated measures 2-way ANOVA and Tukey test (p<0.001) showed that TiF42, which did not differ from TiF41 and TiF43, revealed a significant reduction in surface loss compared to all control groups. TiF41 and TiF43 showed no significant difference from C1, but both groups demonstrated significantly smaller surface loss than C2 and C3. ESEM and AFM micrographs suggested alterations on treated surfaces compared to samples from control groups, showing reduced diameters of dentinal tubules lumens. Therefore, TiF4 was able to reduce the progression of erosive/abrasive lesions.

Strong effect on dentin after the use of high concentrations of citric acid: An assessment with co-site optical microscopy and ESEM

Effects of iron removal treatments on the chemical and viscoelastic properties of waterlogged wood

Conventional scanning and transmission electron microscopy (SEM and TEM) of the rhizosphere (soil around plant roots) has been used to describe the spatial organization of biotic (microorganisms including bacteria and fungi) and abiotic (organomineral complexes and clay platelets) constituents in soil.1 However, soil is deeper than plant rootS2 and the spatial distribution of microbes, the morphology of the microbial growth habit, and the spatial association of microbes with mineral substrates in the deeper vadose zone are little known. That subsurface terrestrial microbes catalyze most major nutrient-cycling reactions in the terrestrial biosphere3 punctuates the need to observe the true morphology of bacteria in association with mineral surfaces and microbemicrobe associations. Here, we present our use of environmental scanning electron microscopy (ESEM) to image bacteria on unsaturated sand, a simple surrogate for heterogeneous soil. ESEM is a choice tool for high resolution imaging of combined soft and hard matter, where delicate hydrated expolymer matrices bind microbes to each other and to soil particles as biofilm.4

The aim of this study was the effects of different light curing methods on marginal sealing and resin composite adaptation to the cavity wall using the dye penetration test and environmental scanning electron microscope (SEM) observations. Cylindrical cavities were prepared on cervical regions. The teeth were restored with Clearfil Liner Bond 2 V adhesive and filled with Clearfil Photo Bright or Palfique Estelite resin composites. These resins were cured with a conventional light-curing method or a slow-start curing method. After thermal cycling, the specimens were subjected to the dye penetration test to evaluate marginal sealing and adaptation of the resin composites to the cavity walls. These resin-tooth interfaces were then observed using environmental SEM. The light-cured resin composite, which exhibited increased contrast ratios during polymerization, suggests high compensation for polymerization stress using the slow-start curing method. There was a high correlation between dye penetration test and environmental SEM observation.

The oxidation behavior of stainless steels is principally affected by the early stages of the oxidation process. In this study, the initial corrosion behavior of a high-alloy stainless steel (Snicro25, 25Ni-22Cr) was investigated through Environmental Scanning Electron Microscopy (ESEM) exposure. The corrosion coupons were first contaminated by KCl(s) and then exposed in-situ for one hour at 450°C. The ESEM in-situ experiment provided continuous imaging during the early stages of the degradation process. Ex-situ exposures were also carried out using well-controlled reference exposures to substantiate the ESEM in-situ experiment and in order to evaluate the effect of the presence of electron beam and the lower pressure in the ESEM chamber. The post-exposure analyses were conducted on the surface and on the cross section of the exposed samples using high-resolution Transmission Electron Backscatter Diffraction (t-EBSD) technique, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Focused Ion Beam milling (FIB). TEM and SEM observations were coupled with the chemical concentration analysis using the energy dispersive X-ray spectroscopy (EDX) technique. Ultrafine grain sized oxide scale was formed with the thickness of around 50 to 100 nm further away from the salt particles. The t-EBSD analysis revealed the changes in the crystallographic orientation of the substrate and also the detection of high misorientation regions (HMRs) beneath the oxide layer and in the depletion zones.

Observation de ligaments artificiels de genou après implantation en MEB à pression variable