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101.
Weronika
liewska Katarzyna Struszczyk-
wita Olga Marchut-Mikoajczyk 《International journal of molecular sciences》2022,23(8)
Salty environments are widely known to be inhospitable to most microorganisms. For centuries salt has been used as a food preservative, while highly saline environments were considered uninhabited by organisms, and if habited, only by prokaryotic ones. Nowadays, we know that filamentous fungi are widespread in many saline habitats very often characterized also by other extremes, for example, very low or high temperature, lack of light, high pressure, or low water activity. However, fungi are still the least understood organisms among halophiles, even though they have been shown to counteract these unfavorable conditions by producing multiple secondary metabolites with interesting properties or unique biomolecules as one of their survival strategies. In this review, we focused on biomolecules obtained from halophilic filamentous fungi such as enzymes, pigments, biosurfactants, and osmoprotectants. 相似文献
102.
Carina Morando Osvaldo Fornaro Olga Garbellini Hugo Palacio 《Journal of Materials Science: Materials in Electronics》2014,25(8):3440-3447
During last few decades, emerging environmental regulations worldwide, more notably in Europe and Japan, have targeted the elimination of Pb usage in electronic assemblies due to the inherent toxicity of this element. This situation drives to the replacement of the Sn–Pb solder alloy of eutectic composition commonly used as joining material to suitable lead-free solders for microelectronic assembly. Sn-based alloys containing Ag, Cu, Bi, and Zn are potential lead-free solders, usually close to the binary or ternary eutectic composition. For this reason a great effort was directed to establish reliable thermophysical data fundamental to interpret the solidification process and fluidity of alloys belonging to these systems. In this work, an analysis of the solidification process of pure Sn, binary Sn–Ag, Sn–Cu, Sn–Bi, Sn–Zn, Sn–Pb and ternary Sn–Ag–Cu eutectic alloys was carried out using computer aided-cooling curve analysis and differential scanning calorimetry. 相似文献
103.
Minna Puustinen Olga Volckaert-Legrier Danile Coquin Josie Bernicot 《Computers & Education》2009,53(4):1040-1047
This study analyzes middle school students’ spontaneous mathematics-related help-seeking behavior, in view of making ecologically valid recommendations for the design of supporting tools or “help systems”. Our aim was to investigate the content of students’ help-seeking messages – Are there different forms of help-seeking messages and do they evolve with age? We used the archives of a French forum that provides students with free individualized help in mathematics. The data consisted of 206 messages sent by French middle school students over a period of 42 months. The constituent categories of the messages were identified. The results showed that not all middle school students use the same help-seeking “format”. Compared to sixth graders, ninth graders wrote messages containing more constituent categories, i.e., they provided the online expert with more kinds of information. A detailed analysis of the categories further showed that older students’ messages more often contained explicit help requests and contextual information than did younger students’ messages. Thus, the messages of the oldest students (age 15) were both cognitively more understandable and socially more acceptable than those of the youngest students (age 11). The interpretation of these findings and their implications for designing help systems are discussed. 相似文献
104.
Stefania Romeo P. Thomas Vernier Olga Zeni 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(9):854-862
Electroporation (electropermeabilization) increases the electrical conductivity of biological cell membranes and lowers transport barriers for normally impermeant materials. Molecular simulations suggest that electroporation begins with the reorganization of water and lipid head group dipoles in the phospholipid bilayer interface, driven by an externally applied electric field, and the evolution of the resulting defects into water-filled, lipid pores. The interior of the electroporated membrane thus contains water, which should provide a signature for detection of the electropermeabilized state. In this feasibility study, we use THz time-domain spectroscopy, a powerful tool for investigating biomolecular systems and their interactions with water, to detect electroporation in human cells subjected to permeabilizing pulsed electric fields (PEFs). The time-domain response of electroporated human monocytes was acquired with a commercial THz, time-domain spectrometer. For each sample, frequency spectra were calculated, and the absorption coefficient and refractive index were extracted in the frequency range between 0.2 and 1.5 THz. This analysis reveals a higher absorption of THz radiation by PEF-exposed cells, with respect to sham-exposed ones, consistent with the intrusion of water into the cell through the permeabilized membrane that is presumed to be associated with electroporation. 相似文献
105.
The notion of s-map introduced in quantum logics to define conditional expectations for non-compatible events is studied in projection lattices of von Neumann algebras. It is shown that every tracial state gives rise to an s-map, and conversely, every s-map defines a tracial state. 相似文献
106.
Carlo S. Iorio Olga Goncharova Oleg A. Kabov 《Microgravity science and technology》2009,21(Z1):313-319
When a layer of volatile liquid is exposed to a shear flow of inert gas, thermal patterns, in the form of interfacial ripples
and bulk plumes, are created by the combined action of evaporative, shear-driven and surface-tension-driven instabilities.
The topology of the interfacial thermal patterns is mainly influenced by the geometry of the evaporating surface, the thickness
of the evaporating layer, the intensity of the shear flow and by the physic-chemical properties of the working fluid. In this
paper, by means of numerical simulations, we focused our attention on the dynamics of the interfacial thermal patterns for
different working fluids and thicknesses of the volatile liquid layer. This study has been performed in the frame of the ESA
sponsored Space Program on heat and mass transfer CIMEX-1. The choice of the fluids—ethyl alcohol and FC72 (n-perfluorohexane)—the
reference values for the inert gas flow rate, the thickness of the liquid layer as well as the geometrical features of the
computational domain correspond exactly to the ones foreseen for the CIMEX-1 experiment. However, the main conclusions can
be considered of more general validity. 相似文献
107.
Olga Leon Estrella Rogel Gustavo Torres Andres Lucas 《Petroleum Science and Technology》2013,31(7-8):913-927
ABSTRACT The electrophoretic mobilities of asphaltenes in n-heptane and ethanol were determined. The asphaltenes studied show a positive charge in both solvents. However, the magnitude of the charge is considerably lower in n-heptane than in ethanol. It is concluded that although the electrostatic forces are presented in both solvents, the van der Waals’ atractive forces are the main responsable for the flocculation of asphaltene particles. The addition of a well known asphaltene stabilizer, dodecyl benzene sulphonic acid (DBSA), decreases the electrophoretic mobility of asphaltene particles in ethanol until a constant positive value is reached. This means that the neutralization of the positive charges of the asphaltene particles is not complete, probably due to the limited adsorption of the DBSA on asphaltene surface and also, to the presence of charges inside the asphaltene particles that are not accessible to the DBSA. 相似文献
108.
Ana López Tarek El-Naggar Montserrat Dueñas Teresa Ortega Isabel Estrella Teresa Hernández Mª Pilar Gómez-Serranillos Olga Mª Palomino Mª Emilia Carretero 《Food chemistry》2013
Legumes are the base´s diet in several countries. They hold a high nutritional value, but other properties related to human health are nowadays being studied. The aim of this work was to study the influence of processes (boiling or germination) on the phenolic composition of dark beans (Phaseolus vulgaris L. c.v. Tolosana) and their effect on their antioxidant, neuroprotective and anticancer ability. Phenolic composition of raw and processed dark beans was analysed by HPLC-PAD and HPLC–ESI/MS. The antioxidant activity was evaluated by ORAC. Astrocytes cultures (U-373) have been used to test their neuroprotective effect. Anticancer activities were evaluated on three different cell lines (renal adenocarcinoma (TK-10), breast adenocarcinoma (MCF-7) and melanoma (UACC-62)) by sulphorhodamine B method. Qualitative and quantitative differences in phenolic composition have been observed between raw and processed dark beans that influence the antioxidant activity, mainly for germinated samples which show a decrease of antioxidant capacity. Although every assayed extracts decreased reactive oxygen species release and exhibited cytotoxicity activities on cancer cell lines, raw beans proved to be the most active in neuroprotective and antitumoral effects; this sample is especially rich in phenolic compounds, mainly anthocyanins. This study further demonstrated that phenolic composition of dark beans is related with cooking process and so with their neuroprotective and anticancer activity; cooking of dark beans improves their digestion and absorption at intestinal level, while maintaining its protective ability on oxidative process at cellular level. 相似文献
109.
Michal Firstenberg Kammasandra Nanjunda Shivananda Irit Cohen Olga Solomeshch Vladislav Medvedev Nir Tessler Yoav Eichen 《Advanced functional materials》2011,21(4):634-643
Sequence‐independent or “click”‐type chemistry is applied for the preparation of novel π‐conjugated oligomers. A variety of bi‐functional monomers for Wittig–Horner olefination are developed and applied in a sequential protection–deprotection process for the preparation of structurally similar π‐conjugated oligomers. Selected oligomers are incorporated as the organic semiconductors in light‐emitting diodes and a field‐effect transistor, demonstrating the potential of the approach. 相似文献
110.
During grinding, in cascading mills, the mass distribution of the material moves continuously to finer sizes. Grinding models are usually designed to predict the size distribution of the mill products either as a function of effective breakage events and the time or the energy consumed by the mill. Mill products are always tested for their size analysis and their fineness is usually expressed as the size d through which a certain amount of material passes, i.e. d80. However, particulate materials have some supplementary properties that a grinding model should predict as well. The specific surface area is such an important supplementary property. Initially, the present work examines the relationship between mass distribution and the surface area of ground materials and determines the conditions under which, mass distribution can be used to determine the surface area. Based on these findings the work further examines the operating conditions of a cascading mill under which the surface area of the material increases at the highest rate. The operating parameter examined is the mill load ratio expressed as the mass ratio of mill grinding media and the material present in the mill. 相似文献