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101.
Torres MR Ramos AJ Soler J Sanchis V Marín S 《International journal of food microbiology》2003,81(3):185-193
A scanning electron microscopy (SEM) study of the effect of water activity (a(w)), temperature and fungal interactions on the very early phases of Aspergillus ochraceus, Alternaria alternata and Fusarium verticillioides development on maize grains was carried out. Germination and growth of individual fungal strains were assayed at 0.92, 0.95 and 0.98 a(w), and 20 and 30 degrees C. Hyphal lengths were measured on micrographs taken by SEM at different periods of incubation. A. alternata had the highest linear growth at 0.98 a(w), and was the only species able to grow under all conditions tested, whereas A. ochraceus was not able to germinate at 0.92 a(w) at any temperature assayed. F. verticillioides demonstrated a different behaviour depending on growth temperature. Fungal interactions were studied at 0.95a(w) and 30 degrees C. A. ochraceus germination was inhibited when it was co-inoculated with one or two of the other species. A. alternata showed an increased growth rate when growing together with the other fungi, whereas growth of F. verticillioides was significantly inhibited when paired with A. ochraceus. 相似文献
102.
Yagüe J Paradela A Ramos M Ogueta S Marina A Barahona F López de Castro JA Vázquez J 《Analytical chemistry》2003,75(6):1524-1535
The emergence of proteomics has placed great interest in the understanding of the mechanisms of MS/MS fragmentation of peptides under low-energy collision-induced dissociation. In this work, we describe the presence of anomalous fragments, which correspond to neutral loss elimination of internal amino acids from ions of the b series in quadrupole ion trap MS/MS spectra from naturally occurring peptides. Internal amino acid elimination occurred preferentially with aliphatic amino acids. The phenomenon was more apparent when doubly charged precursors were fragmented and was inhibited when peptides were N-acetylated at the N-terminus. Fragmentation of isomeric peptides where some internal amino acids were relocated in N-terminal position produced MSn spectra indistinguishable from those of the original peptides, indicating that some b ions underwent a structural rearrangement process. Formation of anomalous fragments required a minimum activation time. Our data are consistent with a nucleophile attack of the N-terminal nitrogen over the electrophilic carbonyl carbon at one peptide bond, forming a cyclic b ion intermediate that, by reopening at preferential sites, exposes internal amino acids to the C-terminal side. 相似文献
103.
The objective of this study consists, firstly, of quantifying differences between Spanish universities’ output (in terms of
publications and citations), and secondly, analysing its determinants. The results obtained show that there are factors which
have a positive influence on these indicators, such as having a third-cycle programme, with public financing obtained in competitive
selection procedures, having a large number of full-time researchers or involvement in collaborations with international institutions.
However, other factors which appear to have the opposite effect were also noted. These include a higher number of students
per lecturer or a lower proportion of lecturers with recognised six-year periods. 相似文献
104.
San Andres E. Pantisano L. Ramos J. Roussel P.J. O'Sullivan B.J. Toledano-Luque M. DeGendt S. Groeseneken G. 《Electron Devices, IEEE Transactions on》2007,54(7):1705-1712
We present an experimental methodology that demonstrates the suitability of the conventional three-lumped- parameter model for gate impedance of MOSFET devices at frequencies from dc to the gigahertz range, which permits accurate extraction of model parameters. The parasitic effects at a high frequency are minimized by using radio frequency techniques (i.e., short return paths and de-embedding structures), whereas a robust parameter extraction algorithm overcomes possible instrument inaccuracies. When combined, these allow simultaneous extraction of all three parameters (i.e., Cgate, RDT and Rseries) from the model. The technique is applied to conventional SiO2 -based MOSFET devices and to ultraleaky HfO2 devices with aggressively scaled gate dielectric thickness. 相似文献
105.
This paper presents a turbidity measuring system based on a modulated four infrared (IR) light beam architecture with advanced data processing. The turbidity sensing component consists of a pair of IR light-emitting diodes (LEDs) connected to a current drive controlled through the pulsewidth modulated (PWM) outputs of a multifunction input/output board. The scattered and transmitted IR light in the media under test is detected by a two-channel IR photodiode module that includes a set of transimpedance and programmable gain amplifier. The voltages proportional to the detectors' output currents, are acquired using a 12-bit ADC included in a microcontroller and RS232 transmitted to a laptop personal computer (PC) that works as an advanced control and processing unit. Using optimal neural network processing architectures, an accurate extraction of the turbidity information is performed. A practical approach concerning the neural network architectures [multilayer perceptron single-input-single-output (SISO), multiple-input-single-output (MISO)] including neural network training and testing is discussed in the paper. The multi-input architectures prove to be a robust and general solution for the proposed application. Results from a turbidity measuring system that was designed for automated standalone remote operation with sensing channel autocalibration capabilities are presented 相似文献
106.
Detection of Moisture and Methanol Gas Using a Single Electrospun Tin Oxide Nanofiber 总被引:1,自引:0,他引:1
This letter reports the fabrication of a gas sensor based on a single tin oxide nanofiber made from dimethyldineodecanoate tin using electrospinning and metallorganics decomposition techniques. The fabricated sensor has been used to detect moisture and methanol gas. It showed high sensitivity to both gases and the response times of the complete testing system are in the range of 108-150 s for moisture, and 10-38 s for methanol gas, respectively. 相似文献
107.
Maria Teresa Vieira Ana S. Ramos José M. Castanho João C. Oliveira Albano Cavaleiro 《Journal of Materials Science》2007,42(22):9145-9153
This paper reviews thin films constituted by elements based on the Ti–Al–N system, bearing in mind the role of the condensed
phases in the development of structural components and functional devices. In recent decades, the Ti–Al, Ti–N and Al–N nanocrystalline
binary systems have rapidly attracted research and industry interest. These systems have revealed a great performance via
atomic-level structural control, making it possible to tailor new atomic structures and morphologies suitable in different
applications as protective and hard coatings and as thermal/diffusion barriers. The binary phases based on nitrogen were the
first to exhibit a wealth of interesting mechanical and electrochemical behaviours. However, more recently the Ti-Al and,
particularly, the Ti1 − x
Al
x
N thin films have been applied with success in the industry. The purpose of this paper is to compile the master results concerning
the production and characterisation of binary and ternary thin films of the Ti–Al–N system using similar deposition strategies.
These materials form a good base to analyse the correlation between the chemical composition and the atomic structure, the
preferred orientations and the morphology of 2D monolithic materials. The deposition strategies adopted and the thin films’
chemical compositions determine the as-deposited structures and, consequently, the mechanical behaviour of the thin films
produced, particularly the hardness. In general, an intermediary amorphous stage is observed, i.e., the thin films exhibit
a loss of crystallinity in the transition from a saturated solid solution to a new compound. 相似文献
108.
Silole‐Based Red Fluorescent Organic Dots for Bright Two‐Photon Fluorescence In vitro Cell and In vivo Blood Vessel Imaging
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Bin Chen Guangxue Feng Bairong He Chiching Goh Shidang Xu Gabriel Ramos‐Ortiz Laura Aparicio‐Ixta Jian Zhou Laiguan Ng Zujin Zhao Bin Liu Ben Zhong Tang 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(6):782-792
Robust luminescent dyes with efficient two‐photon fluorescence are highly desirable for biological imaging applications, but those suitable for organic dots fabrication are still rare because of aggregation‐caused quenching. In this work, a red fluorescent silole, 2,5‐bis[5‐(dimesitylboranyl)thiophen‐2‐yl]‐1‐methyl‐1,3,4‐triphenylsilole ((MesB)2DTTPS), is synthesized and characterized. (MesB)2DTTPS exhibits enhanced fluorescence efficiency in nanoaggregates, indicative of aggregation‐enhanced emission (AEE). The organic dots fabricated by encapsulating (MesB)2DTTPS within lipid‐PEG show red fluorescence peaking at 598 nm and a high fluorescence quantum yield of 32%. Upon excitation at 820 nm, the dots show a large two‐photon absorption cross section of 3.43 × 105 GM, which yields a two‐photon action cross section of 1.09 × 105 GM. These (MesB)2DTTPS dots show good biocompatibility and are successfully applied to one‐photon and two‐photon fluorescence imaging of MCF‐7 cells and two‐photon in vivo visualization of the blood vascular of mouse muscle in a high‐contrast and noninvasive manner. Moreover, the 3D blood vasculature located at the mouse ear skin with a depth of over 100 μm can also be visualized clearly, providing the spatiotemporal information about the whole blood vascular network. 相似文献
109.
The aim of this work is to model and simulate the humanoid robot HOAP-3 in the OpenHRP3 platform. Our purpose is to create a virtual model of the robot so that different motions and tasks can be tested in different environments. This will be the first step before testing the motion patterns in the real HOAP-3. We use the OpenHRP3 platform for the creation and validation of the robot model and tasks. The procedure followed to reach this goal is detailed in this article. In order to validate our experience, different walking motions are tested and the simulation results are compared with the experimental ones. 相似文献
110.
The aim of this work is to develop analogue concepts of column reduced polynomial matrices for proper rational matrices. A definition of column reducedness for a class of proper rational matrices is proposed and the properties of such matrices are studied, in particular reduction to column reduced form by elementary operations over the ring of proper rational functions, and the relationship between the degrees of the invariant factors of a column reduced matrix and the so-defined column indices. The physical significance of such matrices in terms of their finite structure is explained; this interpretation completely complements the physical interpretation of a column reduced polynomial matrix. An application of the properties of column reduced proper rational matrices to the decoupling problem is also presented: the infinite structure which can be obtained while decoupling a linear multivariable system by non-regular static state feedback is completely characterized. 相似文献