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关键词： Collagen   Scaffold   Crosslinking   Crosslink density   Degradation  

摘要： The optimization of collagen-based scaffolds for tissue engineering goes through the careful selection of the crosslinking method(s), which should impart the prerequisite mechanical and degradation properties without impairing the cell/tissue response. Here, we investigated the chemically effective (rho(xch)) and the elastically effective (rho(xel)) crosslink density of collagen-based scaffolds, induced by various crosslinking methods. The aim was to get a deeper insight into the influence of intramolecular and intermolecular crosslinks on several scaffold properties. Freeze-dried collagen matrices were crosslinked via a dehydrothermal treatment (DHT), and then treated with different chemical agents, including carbodiimide (EDC), glutaraldehyde (GTA), formaldehyde (FA), genipin (GP) and dimethyl suberimidate (DMS). Quantification of primary amines and stress-relaxation compressive tests were performed to evaluate rho(xch) and rho(xel), respectively. Scaffolds were then assessed for their water uptake, thermal stability and in vitro resistance to enzymatic degradation. Interestingly, for the various crosslinking treatments rho(xch) was found to increase in the order DHT < DHT + GP < DHT DMS < DHT GTA < DHT + FA < DHT EDC, while rho(xel) increased according to this slightly different trend: DHT < DHT + GP < DHT DMS < DHT EDC < DHT GTA < DHT + FA. Indeed, treatment DHT EDC induced a higher rho(xch) but a lower rho(xel) than aldehyde-based ones. This finding, together with the higher denaturation temperature (T-d) of EDC-treated samples compared to others, suggested that zero-length EDC crosslinking promoted intramolecular crosslinks, along with intermolecular ones. Accordingly, the increase of T-d was correlated with the increase of rho(xch) rather than rho(xel), whereas the decrease in water uptake was consistent with the increase of rho(xel), as expected. An exponential relationship between rho(xel) and the in vitro half-life was also determined.

关键词： alkaline glass   glass wafer   anodic bonding   micromechanical sensor  

摘要： The physicochemical processes occurring in the structure of alkaline glass and at a silicon - glass interface with anodic bonding of the glass and silicon wafers were studied. The bonding of these materials is now widely used in industry in the development of sensitive elements of micromechanical sensors, such as pressure, acceleration, and other sensors. It is shown that in order to obtain a high-quality bond both the parameters of the technological process (for example, the applied voltage) and the structural features of the bonded parts (for example, the thickness of the glass wafers) can be varied.

关键词： atmospheric plasma   dielectric barrier discharge (DBD)   germination   irrigation   plasma agriculture   surface analysis   wheat seed  

摘要： Plasma treatment is increasingly being explored as an effective presowing treatment improving seed germination. This study examines the synergetic effect of the irrigation condition and the physicochemical surface properties of wheat seeds subjected to atmospheric dielectric barrier discharge plasma activation on their water uptake and germination. Extensive surface analysis revealed a remarkably enhanced wettability of plasma-treated seeds due to the insertion of oxygen-containing functionalities on their surface. However, long plasma exposures damaged the outermost layers of the pericarp due to a pronounced oxidative etching effect. Although the seed germination capacity was not affected by the plasma treatments, short plasma exposures were shown to enhance water uptake and accelerate seed germination, especially under water-scarcity conditions.

关键词： Wall rock alteration   Hydrothermal process   Chlorite geothermometry   Vein-type uranium deposit   Shahapur granite   Eastern Dharwar craton  

摘要： Eastern Dharwar craton (EDC) is a major uranium province in India hosting number of unconformity related, vein-type and carbonate hosted strata-bound uranium deposits. Gogi uranium deposit (GUD) is a structurally controlled hydrothermal ore deposit (similar to 1.35 Ga), hosted in a reverse fault zone between the foot-wall Mesoproterozoic Bhima Group carbonates and the hanging wall basement granites (similar to 2.5 Ga) of the EDC. The hanging wall granites, locally known as Shahapur granite show extensive chloritisation and epidotisation, and constitute the propylitic outer zone of the main hydrothermal system of the GUD. We conducted systematic mineralogical and geochemical studies on hydrothermally altered assemblages to understand physico-chemical conditions of hydrothermal fluid. Quartz, epidote, chlorite, titanite, fluorite and hematite are the main hydrothermal mineral phases. Chlorites occur in two different forms, as pseudomorphic replacement of hornblende and as vein/cavity fillings. Epidotes occur as coarse prismatic grains in the main veins, or as replacement of albite in the wall rock. Mineralogical, textural data and geochemical mass balance calculation indicate that about 17.9% of total albites (Modal abundance =similar to 48%) and all the hornblendes (modal abundance =similar to 7.5%) of the parent rock were broken down and reacted to form quartz, chlorite, epidote, secondary titanite and hematite. The hydrothermal reaction resulted in creation of 13 vol% secondary porosity in the host rock and acidification of the evolved fluid. Thermodynamic calculation on chlorite compositions indicates 250 degrees C temperature of formation and oxidising nature of ambient fluid, with log fO(2) ranging between-37 and similar to 31 (avg.-35). Available fluid inclusion data, in conjunction with chlorite geothermometric results, show fluid entrapment pressure between 625 bar and 792 bar, which is consistent with emplacement of hydrothermal fluid in low-pressure brittle

关键词： Monofloral honey   Phytochemicals   Total anti-oxidant activity   Valued products   Chemometrics  

摘要： The effects of iron and copper on the total in vitro anti-oxidant activity of Hellenic monofloral honeys (citrus, fir, pine, and thyme) under the presence of phytochemicals were presented for the first time in the literature. Authenticity issues were also investigated using supervised statistical techniques on the data set measured which consisted of effective acidity (pH), color intensity (brown pigments), in vitro anti-oxidant activity, total phytochemical content, copper (Cu), and iron (Fe) contents. Results showed that in vitro anti-oxidant activity was positively correlated (p < 0.05) with total phytochemical, copper, and iron contents, along with color intensity and pH in relation to honey botanical origin. Therefore, new terms as those of "total anti-oxidant activity'' and "total phytochemical content'' may be proposed to describe the antioxidant activity developed under the presence of phytochemicals and catalytic minerals such as Cu and Fe. Chemometric techniques such as multivariate analysis of variance, linear discriminant analysis,k-nearest neighbors and bootstrap analyses in combination withzscore test confirmed the above theory, contributing thus, to an added value of Hellenic monofloral honey in the food chain.

关键词： Lactococcus   Tonga   Microbial communities   Aroma compounds   Spontaneous fermentation  

摘要： Fermentation temperature is a crucial factor in the production of fermented dairy products. This study investigated the influence of fermentation temperature on physiochemical properties and the composition of the microbial communities of two types of mabisi: tonga and barotse mabisi. Mabisi is a traditionally fermented milk product made in Zambia by spontaneous fermentation of raw milk at ambient temperature. The two types of mabisi were produced with tonga mabisi fermented at 20, 22, 25 and 30 degrees C, and barotse mabisi at 25 and 30 degrees C. The pH, titratable acidity, syneresis, consistency, microbial community composition and aroma compounds were determined. We found that fermentation at 20 and 22 degrees C was slower than at 25 degrees C but they all produced tonga mabisi with medium acidity (pH 4.2) and 'medium' consistency within 48 h. Fermentation was most rapid at 30 degrees C but resulted in a product with a 'thin' consistency. Fermentation temperature did not affect the microbial community composition of tonga mabisi, which remained diverse and complex with Lactococcus as the dominant fermenting genus. However, in barotse mabisi, at 25 degrees C, the product had 'thick' consistency and the microbial community composition was dominated by Lactococcus whereas at 30 degrees C the product was thicker, more acidic and dominated by Lactobacillus.

关键词： Phospholipids  

摘要： This study evaluated the behavior changes of two types of phospholipid emulsions under ultrasonic treatment. The phosphatidylcholine (PC) contents for PC 50 and PC 90 were 58 and 90%, respectively. The results showed that acid value and fatty acid compositions of the two phospholipids showed no significant differences (p > .05) before and after ultrasonic treatment. The peroxide value and volatile compounds revealed that PC 50 had stronger oxidative stability than PC 90, which indicated that the synergistic effect of PC and other phospholipids components could enhance the oxidative stability of individual phospholipids. This work suggests that appropriate ultrasonic treatment could make phospholipids finely dispersed in aqueous system and promote their contact efficiency with 2,2-diphenyl-1-picrylhydrazyl, resulting in the increase in antioxidant ability of the phospholipid emulsions. However, prolonged ultrasonic treatment could induce the self-oxidation of phospholipids, and more attention should be paid to the self-oxidation of these phospholipids when ultrasound was applied in food processing. Practical Applications This study evaluated the behavior changes of two types of phospholipids under ultrasonic treatment. The findings of this study could be useful for guiding the future usage of phospholipids and ultrasound in the food industry.

关键词： Micro-biochars   ROS   Oxidative DNA damage   Epithelial barrier   Pyrolysis temperature  

摘要： Biochars (BCs) are currently widely used, yet their impact on human health is mostly unknown. We generated micro-tobacco stem-pyrolysed BCs (mTBCs) at different pyrolysis temperatures and assessed pulmonary toxicity in normal human lung epithelial BEAS-2B cells. mTBCs generated at 350 degrees C (mTBC350) and 650 degrees C (mTBC650) were analysed and compared for physicochemical properties and adverse effects. Pyrolysis temperature had a significant influence on chemical composition, particle size, specific surface area and aromatic carbon structure. mTBC650 displayed a highly ordered aromatic carbon structure with smaller particle size, high surface area (20.09 m2/g) and high polycyclic aromatic hydrocarbon and metal content. This composition could promote reactive oxygen species accumulation accompanied by greater cytotoxicity, genotoxicity and epithelial barrier malfunction in cultured cells. Thus, the risk of pulmonary toxicity owing to micro-BCs (mBCs) is affected by pyrolysis temperature. Long-term exposure to mBCs produced at high temperatures may lead to or exacerbate pulmonary disease. (C) 2020 Elsevier Ltd. All rights reserved.

摘要： Statement of problem. Changes in physicochemical properties because of implant material aging and natural deterioration in the oral environment can facilitate microbial colonization and disturb the soft-tissue seal between the implant surfaces. Purpose. The purpose of this in vitro study was to investigate the effect of aging time on the physicochemical profile of titanium (Ti) and zirconia (ZrO2) implant materials. Further microbiology and cell analyses were used to provide insights into the physicochemical implications of biological behavior. Material and methods. Disk-shaped specimens of Ti and ZrO2 were submitted to roughness, morphology, and surface free energy (SFE) analyses before nonaging (NA) and after the aging process (A). To simulate natural aging, disks were subjected to low-temperature degradation (LTD) by using an autoclave at 134 degrees C and 0.2 MPa pressure for 20 hours. The biological activities of the Ti and ZrO2 surfaces were determined by analyzing Candida albicans (C. albicans) biofilms and human gingival fibroblast (HGF) cell proliferation. For the microbiology assays, a variance analysis method (ANOVA) was used with the Tukey post hoc test. For the evaluation of cellular proliferation, the Kruskal-Wallis test followed by Dunn multiple comparisons were used. Results. Ti nonaging (TNA) and ZrO2 nonaging (ZNA) disks displayed hydrophilic and lipophilic properties, and this effect was sustained after the aging process. Low-temperature degradation resulted in a modest change in intermolecular interaction, with 1.06-fold for TA and 1.10-fold for ZA. No difference in biofilm formation was observed between NA and A disks of the same material. After 48 hours, the viability of the attached HGF cells was very similar to that in the NA and A groups, regardless of the tested material. Conclusion. The changes in the physicochemical properties of Ti and ZrO2 induced by the aging process do not interfere with C. albicans biofilm formation and HGF cell atta

关键词： ball milling starch   glutinous rice starches   mucoadhesive film formers   physically modified starches   waxy starches  

摘要： This study aims to investigate the physicochemical and mucoadhesive properties of films made of glutinous rice starch (GRS), native (NGRS), and ball-milled modified GRS (MGRS), in comparison with the reference mucoadhesive polymers. By using the solvent casting technique with glycerol (30% w/w of starch mass) as a plasticizer, all GRS films exhibit satisfactory and comparable thickness and weight uniformity, surface pH, and moisture content. ATR-FTIR indicates that the hydrogen bonds are formed between GRS and glycerol. The absence of crystalline structure of GRS in glycerol plasticized films is confirmed using ATR-FTIR and XRD. The films made of NGRS and MGRS have similar swelling behavior (751 +/- 75 to 1002 +/- 104%), whereas those made of longer milling time MGRS demonstrate higher erosion (27.1 +/- 4.2%) (p< 0.05). MGRS films exhibit greater flexibility with lower tensile strength (9.6 +/- 1.7 to 9.8 +/- 1.0 MPa) but higher elongation (162.5 +/- 6.5 to 165.7 +/- 2.5%) compared to native systems (13.7 +/- 0.5 MPa and 128.1 +/- 5.0%, respectively) (p< 0.05). The MGRS films show comparable mucoadhesiveness expressed as detachment force and work of adhesion to those of sodium carboxymethylcellulose, but higher than those of NGRS, hydroxypropyl methylcellulose, and chitosan (p< 0.05). This study reveals the potential exploitation of GRS as a mucoadhesive film former for pharmaceutical application.