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711.
Fleisch MC Maxwell CA Kuper CK Brown ET Barcellos-Hoff MH Costes SV 《Microscopy research and technique》2006,69(12):964-972
Centrosomes are small organelles that organize the mitotic spindle during cell division and are also involved in cell shape and polarity. Within epithelial tumors, such as breast cancer, and some hematological tumors, centrosome abnormalities (CAs) are common, occur early in disease etiology, and correlate with chromosomal instability and disease stage. In situ quantification of CA by optical microscopy is hampered by overlap and clustering of these organelles, which appear as focal structures. CA has been frequently associated with Tp53 status in premalignant lesions and tumors. Here the authors described an approach to accurately quantify centrosome frequencies in tissue sections and tumors, independently of background or noise levels. Applying simple optical rules in nondeconvolved conventional 3D images of stained tissue sections, the authors showed that they could evaluate more accurately and rapidly centrosome frequencies than with traditional investigator-based visual analysis or threshold-based techniques. The resulting population-based frequency of centrosomes per nucleus could then be used to approximate the proportion of cells with CA in that same population. This was done by taking into account baseline centrosome amplification and proliferation rates measured in the tissue. Using this technique, the authors showed that 20-30% of cells have amplified centrosomes in Tp53 null mammary tumors. 相似文献
712.
Michael Peusch Erika Müller-Seitz Michael Petz 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1996,202(4):334-336
Capsaicin, dihydrocapsaicin and nordihydrocapsaicin were determined in paprika powders and oleoresins after clean-up on silica and aluminium oxide with controlled activity followed by isocratic reverse-phase HPLC (RP-HPLC) with fluorescence detection. Caprylic acid vanillylamide (CVA) was synthesized for use as internal standard. Samples with less than 0.6 g/g (10 Scoville Heat Units) were analysed. 相似文献
713.
Present work reports on electrical properties of polyurethane elastomer/polyaniline (PU/PANI-HCl) composite films under tensile deformation. Two types of surface-modified and one type of volume-modified composite of PU and PANI-HCl were prepared. Surface modification of PU film was performed by swelling the parent film in aniline followed by its contact with the acidified oxidant solution to polymerize aniline and form PANI-HCl distributed inside surface/subsurface layer of the film. Volume-modified PU was prepared by mixing of the polymer components in a joint solution and then solution casting. Nonlinear current-voltage characteristics were observed for surface-modified samples while linear ones were typical of volume-modified samples. Deformation of the polymer composites caused partially reversible decrease of their conductivity characteristics, which could be described mathematically with a power law function of the strain with an exponent being dependable on the type of PU modification. Such behavior was interpreted in terms of deformation of a fractal percolation network formed in the system during its formation and chemical synthesis. 相似文献
714.
Base-catalyzed transesterification of acyl lipids with trimethylsulfonium hydroxide (TMSH) is an easy and convenient method
for the preparation of fatty acid methyl esters (FAME) for gas chromatography (GC) analyses. We have found, however, that
lipids containing hydroxy groups are partially converted to the correspondingO-methyl ether derivatives which may interfere with FAME in GC separations. For example, long-chain alcohols are found to be
converted to alkyl methyl ethers,rac-1-O-alkylglycerols to the corresponding 2-O-and 3-O-monomethyl ethers, as well as 2,3-di-O-methyl ethers, hydroxy fatty acids to methoxy FAME, and cholesterol to cholesteryl 3β-methyl ether. From our results, it
is obvious that TMSH derivatization method is not recommended without limitation for lipids containing hydroxy groups; it
may be, however, of some diagnostic value for the analysis of such lipids by GC/mass spectrometry. 相似文献
715.
716.
Story Lisa B.; Karney Benjamin R.; Lawrence Erika; Bradbury Thomas N. 《Canadian Metallurgical Quarterly》2004,18(3):519
Intergenerational transmission of marital functioning was examined in a sample of 60 newlywed couples by collecting (a) retrospective reports of conflict and divorce in spouses' families of origin, (b) data on demographic variables and interactional processes likely to increase risk for adverse marital outcomes, and (c) couples' actual 4-year marital outcomes. The association between wives' parental divorce and marital outcome was mediated by their verbal and physical aggression. The association between negativity in husbands' family of origin and marital outcome was mediated by dyadic expressions of negative affect. Demographic variables did not operate as mediators. Negative interpersonal processes appear to be a vehicle by which experiences in the family of origin are carried forward into the next generation of relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
717.
Erika Daley Michael D. Kurdziel Denise Koueiter Drew D. Moore 《Journal of materials science. Materials in medicine》2018,29(7):109
Percutaneous doxycycline for treatment for aneurysmal bone cysts (ABCs) has been shown to decrease recurrence rates, however, this requires multiple procedures, includes the risks soft tissue necrosis, and does not provide structural support. We propose utilizing curettage with doxycycline-loaded calcium phosphate cement. This study aimed to evaluate the elution profile of doxycycline from calcium phosphate cement. Calcium phosphate cement underwent an in vitro elution protocol evaluating doxycycline concentrations of 0, 5, 10, and 15?mg/mL. Eluted concentrations were quantified utilizing high performance liquid chromatography at predetermined time points over 96?h. Compressive strength was evaluated both pre- and post-elution and micro-computed tomography was utilized to assess changes in cement porosity. Cement with 15?mg/mL of doxycycline maintained a higher average concentration (mean, 95% confidence intervals) (14.5?µg/mL [9.2–19.9?µg/mL]) compared to both 5?mg/mL (5.8?µg/mL [3.1–8.6?µg/mL]; P?<?0.001) and 10?mg/mL (8.4?±?µg/mL [6.0–10.9?µg/mL]; P?<?0.001). Ultimate stress significantly decreased between pre- and post-elution samples for 10?mg/mL (P=?0.001) and 15?mg/mL (P?=?0.004) groups. This study demonstrated a dose-dependent response in ultimate strength and compressive modulus with addition of doxycycline to calcium phosphate cement. 相似文献
718.
Federica Mariani Felipe Conzuelo Tobias Cramer Isacco Gualandi Luca Possanzini Marta Tessarolo Beatrice Fraboni Wolfgang Schuhmann Erika Scavetta 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(42)
A comprehensive understanding of electrochemical and physical phenomena originating the response of electrolyte‐gated transistors is crucial for improved handling and design of these devices. However, the lack of suitable tools for direct investigation of microscale effects has hindered the possibility to bridge the gap between experiments and theoretical models. In this contribution, a scanning probe setup is used to explore the operation mechanisms of organic electrochemical transistors by probing the local electrochemical potential of the organic film composing the device channel. Moreover, an interpretative model is developed in order to highlight the meaning of electrochemical doping and to show how the experimental data can give direct access to fundamental device parameters, such as local charge carrier concentration and mobility. This approach is versatile and provides insight into the organic semiconductor/electrolyte interface and useful information for materials characterization, device scaling, and sensing optimization. 相似文献
719.
720.
Diffusivity of propolis compounds in Polylactic acid polymer for the development of anti-microbial packaging films 总被引:1,自引:0,他引:1
Erika Mascheroni Valérie Guillard Federico Nalin Luigi Mora Luciano Piergiovanni 《Journal of food engineering》2010
A major research gap is the lack of packaging materials that can provide the release of active compounds at rates suitable for a wide range of food packaging applications. For this reason an anti-microbial/antioxidant release system for food packaging applications was realized by incorporation of propolis into Polylactic acid (PLA) film. The composition of the films was modified by adding polyethylene glycol (PEG) and calcium bentonite (CB) to the initial PLA casting solution; dispersed structures in fact open the molecular network and increase migration rates. The presence of the anti-microbial compound is required essentially at the food surface where the microorganisms are numerous and where they are intended to grow. The diffusivity of four polyphenols was measured in water and ethanol as food simulating liquids (FSL) and the concentration of additives at the interface PLA/Food Simulant was calculated using Fickian models. The external mass transfer coefficient at the interface polymer/FSL could be neglected (with Bi number higher than 200). This is due to the low diffusivity values of propolis polyphenols in the PLA matrix (0.03–0.83 × 10–13 m2/s) which lead to a predominant internal mass transfer phenomenon compared to the external one in the system PLA/water. The concentration at interface at equilibrium was different for each substance and depended of the thermodynamical parameter K. Such a delivery system for direct contact with liquid aqueous medium would be a very efficient delivery system because some active agents (polyphenols acids) would be released in relevant quantity in the food whereas others (flavonoids) would remain in the polymer to act at the polymer/food interface. 相似文献