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81.
Raffaella Crescenzo Francesca Bianco Arianna Mazzoli Antonia Giacco Giovanna Liverini Susanna Iossa 《International journal of molecular sciences》2015,16(5):10674-10685
Aging is associated with a progressive loss of maximal cell functionality, and mitochondria are considered a key factor in aging process, since they determine the ATP availability in the cells. Mitochondrial performance during aging in skeletal muscle is reported to be either decreased or unchanged. This heterogeneity of results could partly be due to the method used to assess mitochondrial performance. In addition, in skeletal muscle the mitochondrial population is heterogeneous, composed of subsarcolemmal and intermyofibrillar mitochondria. Therefore, the purpose of the present review is to summarize the results obtained on the functionality of the above mitochondrial populations during aging, taking into account that the mitochondrial performance depends on organelle number, organelle activity, and energetic efficiency of the mitochondrial machinery in synthesizing ATP from the oxidation of fuels. 相似文献
82.
Susanna M. Früh Philipp R. Spycher Dr. Maria Mitsi Melanie A. Burkhardt Prof. Dr. Viola Vogel Dr. Ingmar Schoen 《Chembiochem : a European journal of chemical biology》2014,15(10):1481-1486
A straightforward strategy is presented for the site‐specific incorporation of fluorophores or reactive probes into the extracellular matrix (ECM) protein fibronectin (Fn) by using the enzyme‐catalyzed transamidation by activated factor XIII. Characterization by SDS‐PAGE, western blotting, absorption measurements, mass spectrometry, and stepwise photobleaching for labeling quantification at the single‐molecule level showed that the labeling was efficient and restricted to the N‐terminal tails. The introduction of labels did not interfere with Fn fibrillogenesis, as verified by the incorporation of fluorescently labeled Fn into ECM and manually pulled Fn fibers. Site‐specific incorporation of an azide was used to create a template for bioorthogonal click chemistry reactions in a second bioconjugation step, thus offering versatile modification and application possibilities in the context of matrix biology and tissue engineering. 相似文献
83.
Roberto Scotti Lucia Conzatti Massimiliano D'Arienzo Barbara Di Credico Luca Giannini Thomas Hanel Paola Stagnaro Antonio Susanna Luciano Tadiello Franca Morazzoni 《Polymer》2014
Silica/styrene butadiene rubber (SBR) nanocomposites were prepared by blending method using shape-controlled spherical and rod-like nanoparticles with different aspect ratios as filler for the rubber reinforcement. The differently shaped silica particles were synthesized by sol–gel method using tetraethoxysilane (TEOS) and (3-mercaptopropyl) trimethoxysilane (MPTSM) as silica precursors, and cetyltrimethylammonium bromide (CTAB) as structure directing agent. This strategy allowed to study the influence of the particle morphology on the reinforcing effect independently of the silica surface chemistry and considering the aspect ratio as the only geometrical variance. Spherical and anisotropic rod-like particles, dispersed in the nanocomposites, formed a network of particles bridged by thin rubber layers throughout the SBR matrix. Moreover, differently oriented domains of aligned rods are observed when the aspect ratio of particles increases and is ≥2. Dynamic-mechanical properties demonstrated that the rod-like particles with the higher aspect ratio provided stronger reinforcement of the rubber. This was related to the self-alignment of the anisotropic particles and to the consequent larger filler/polymer interface, compared to that of spherical ones. 相似文献
84.
Nerea Ugartondo Núria Martínez-Gil Mnica Esteve Natlia Garcia-Giralt Neus Roca-Ayats Diana Ovejero Xavier Nogus Adolfo Díez-Prez Raquel Rabionet Daniel Grinberg Susanna Balcells 《International journal of molecular sciences》2021,22(14)
Osteoporosis is the most common metabolic bone disorder and nitrogen-containing bisphosphonates (BP) are a first line treatment for it. Yet, atypical femoral fractures (AFF), a rare adverse effect, may appear after prolonged BP administration. Given the low incidence of AFF, an underlying genetic cause that increases the susceptibility to these fractures is suspected. Previous studies uncovered rare CYP1A1 mutations in osteoporosis patients who suffered AFF after long-term BP treatment. CYP1A1 is involved in drug metabolism and steroid catabolism, making it an interesting candidate. However, a functional validation for the AFF-associated CYP1A1 mutations was lacking. Here we tested the enzymatic activity of four such CYP1A1 variants, by transfecting them into Saos-2 cells. We also tested the effect of commonly used BPs on the enzymatic activity of the CYP1A1 forms. We demonstrated that the p.Arg98Trp and p.Arg136His CYP1A1 variants have a significant negative effect on enzymatic activity. Moreover, all the BP treatments decreased CYP1A1 activity, although no specific interaction with CYP1A1 variants was found. Our results provide functional support to the hypothesis that an additive effect between CYP1A1 heterozygous mutations p.Arg98Trp and p.Arg136His, other rare mutations and long-term BP exposure might generate susceptibility to AFF. 相似文献
85.
Protecting probiotic bacteria by microencapsulation: challenges for industrial applications 总被引:1,自引:0,他引:1
The use of probiotic bacteria in novel foods to provide beneficial health effects is today of increasing interest in the food
industry. The process stability of probiotics is, however, not always optimal. Microencapsulation technology can be used to
maintain the viability of probiotic bacteria during food product processing and storage. Both true microcapsules with coating
as well as microspheres where the bacteria are evenly spread in the coating material are discussed. It is important that encapsulation
keeps the probiotics active through the gastrointestinal tract and releases them in their target organ. The survival of microencapsulated
cells in simulated gastric conditions is therefore also reviewed. Polysaccharides like alginate, gellan, κ-carrageenan and
starch are the most commonly used materials in microencapsulation of bifidobacteria and lactobacilli. Techniques commonly
applied for probiotic microencapsulation are emulsion, extrusion, spray drying, and adhesion to starch. Bead stability can
be improved by using different coating materials, e.g. chitosan. Future challenges in the field include recognition of new
potent applications, selection of appropriate techniques, materials and bacterial strains, and minimizing the extra costs
incurred by microencapsulation. 相似文献
86.
New evidence and theoretical discussion on the complementarity relationships concerning different networking activities and
R&D in a local SME oriented system is presented. R&D arises a main driver of innovation and productivity, even without the
association to networking. The complementarity between diversified networking activities and R&D/innovation is generally found,
in a discrete setting. Non-strict complementarity nevertheless prevails. On the innovation side, complementarity among performance
drivers is more crucial for product/radical innovation, relatively to process innovation, which also witnesses substitutability
signals. Networking can be a complementary factor in situations where cooperation and networking are needed to achieve economies
of scale and/or to merge and integrate diverse skills, technologies and competencies. Managers and policy makers should be
aware that in order to exploit asset complementarity, possibly transformed into competitive advantages, both R&D and networking
are to be sustained and favoured. Networking elements are crucially linked to innovation dynamics; it is nevertheless innovation
that explains and drives networking, and not the often claimed mere existence of local spillovers or of a civic associative
culture in the territory. Such public good factors are likely to evolve with and be sustained by firm innovative dynamics. 相似文献
87.
88.
Kariluoto S Aittamaa M Korhola M Salovaara H Vahteristo L Piironen V 《International journal of food microbiology》2006,106(2):137-143
Fermentation of rye dough is often accompanied with an increase in folate content. In this study, three sourdough yeasts, Candida milleri CBS 8195, Saccharomyces cerevisiae TS 146, and Torulaspora delbrueckii TS 207; a control, baker's yeast S. cerevisiae ALKO 743; and four Lactobacillus spp., L. acidophilus TSB 262, L. brevis TSB 307, L. plantarum TSB 304, and L. sanfranciscensis TSB 299 originally isolated from rye sourdough were examined for their abilities to produce or consume folates. The microorganisms were grown in yeast extract-peptone-d-glucose medium as well as in small-scale fermentations that modelled the sourdough fermentation step used in rye baking. Total folate contents were determined using Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism. The microorganisms studied did not excrete folates into the media in significant amounts. Yeasts increased the folate contents of sterilised rye flour-water mixtures from 6.5 microg/100 g to between 15 and 23 microg/100 g after 19-h fermentation, whereas lactic acid bacteria decreased it to between 2.9 and 4.2 microg/100 g. Strains of Lactobacillus bulgaricus, L. casei, L. curvatus, L. fermentum, L. helveticus, Pediococcus spp., and Streptococcus thermophilus that were also tested gave folate contents after fermentation that varied between 2 and 10.4 microg/100 g. Although the four Lactobacillus spp. from sourdough consumed folates their effect on folate contents in co-cultivations was minimal. It was concluded that the increase of folate content during fermentation was mainly due to folate synthesis by yeasts. Fermentation of non-sterilised flour-water mixtures as such resulted in three-fold increases in the folate contents. Two folate producing bacteria were isolated from the non-sterilised flour and identified as Enterobacter cowanii and Pantoea agglomerans. 相似文献
89.
Gago J. Balcells J. Gonzalez D. Lamich M. Mon J. Santolaria A. 《Electromagnetic Compatibility, IEEE Transactions on》2007,49(4):849-859
Circuits based on operational amplifiers (OPAMPs) are susceptible to electromagnetic interference (EMI) in the radio-frequency range due to the AM demodulation produced by non-linearity of internal transistors. Such a phenomenon produces demodulated signals in the low-frequency range. This paper presents a model to predict the susceptibility of analog signal-conditioning circuits, based on a few test parameters, while ignoring the internal structure of OPAMPs involved in the circuit. The method has been experimentally tested in two applications: (1) test of simple instrumentation adapter circuits and (2) predictions of susceptibility of an amplifier for an electret microphone, tested according to EN55020. 相似文献
90.
Balcells J. Santolaria A. Orlandi A. Gonzalez D. Gago J. 《Electromagnetic Compatibility, IEEE Transactions on》2005,47(3):569-576
Frequency-modulation techniques have been used to reduce electromagnetic interference (EMI) produced by the clock of digital systems working in the range of hundreds of megahertz. The working principle consists of modulating the original constant clock frequency in order to spread the energy of each single harmonic into a certain frequency band, thus reducing the peak amplitude of EMI at harmonic frequencies. Nowadays, the switching frequency of power converters has increased up to values that make interesting the application of such techniques to reduce EMI emissions due to switching of power circuits. This paper presents the theoretical principles of frequency modulation using deterministic profiles for the modulating function. It shows the effectiveness of such methods in terms of EMI reduction for different modulation profiles and other parameters. The method is compared with other methods using random modulation. Tests carried out on a buck converter are presented for experimental validation of the method. A short discussion on optimal modulation profiles and parameters is also included. 相似文献