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Manuel Porcar Silvia Ramos Amparo Latorre 《Journal of the science of food and agriculture》2007,87(14):2728-2731
BACKGROUND: The polymerase chain reaction (PCR) is a powerful tool that is being increasingly used for detection of transgenic DNA. PCR requires only a minute quantity of template, but sensitive and accurate testing requires DNA of sufficient purity and free from inhibitors such as plant polysaccharides. Several standard protocols are available for this purpose, but they usually involve several steps, imply destruction of the maize kernel, or are time‐consuming. Our aim was to develop a fast and simple extraction method to isolate a raw DNA‐containing solution from maize tissues suitable for use as a template in a PCR‐based detection assay with specific oligonucleotides directed to the identification of event MON810. RESULTS: The NaOH‐based DNA extraction method we report here is time‐saving (5 min) and can be used to isolate DNA‐containing solutions from a small maize leaf portion (down to 1 mg) or from a single overnight‐germinated kernel. PCR performed with selected primers yielded reproducible detection of transgenic DNA. CONCLUSION: The main advantages of the procedure are the quick extraction step, the possibility of non‐destructive testing of maize kernels, and the robustness of the PCR‐based detection, a consequence of the selection of MON810‐matching oligonucleotides yielding intense and highly specific amplicons. Copyright © 2007 Society of Chemical Industry 相似文献
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Xavier Chaud Tatiana Prikhna Yaroslav Savchuk Anne Joulain Evert Haanappel Pavel Diko Laureline Porcar Mahmoud Soliman 《Materials Science and Engineering: B》2008,151(1):53
Oxygen high pressure (up to 16 MPa) has been introduced in the oxygen-annealing step necessary to make the YBa2Cu3Ox phase superconducting (change x from 6 to about 7). It enables a displacement in the equilibrium phase diagram towards higher temperatures, which means the possibility to achieve the same final oxygen content as the one at low temperature, but with the benefit of higher diffusion rates. Initial development made on thin bars (1.5–3 mm thick) has confirmed the interest of using a high pressure of oxygen. TEM observations have shown an increase of twin density associated with higher Jc. This is in agreement with other works claiming the possibility of higher Jc by twin engineering, and more precisely by twin refinement while annealing at high temperature. We report the successful application of this process without any adjustment to so-called thin-wall single-domain samples. These samples are obtained by growing a crystal on a pellet already shaped with an array of holes. The advantage is that, as far as diffusion processes are concerned, the typical length is not anymore the diameter of the sample, but the thickness of the walls between holes. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6 T vs. 0.3 T at 77 K) in a rather short annealing time (about 3 days). Microstructures as well as magneto-optical observations of plain and thin-wall samples evidenced a reduction of cracks in the thin-wall samples. Improved performances were confirmed by further characterizations performed from 77 down to 20 K using the pulse-field facilities of the LNCMP at Toulouse. 相似文献
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Accurate knowledge of the thermal properties of building components is necessary to implement adequate energy saving strategies in buildings. Outdoor experiments using test cells are very useful tools for realistic estimation of these properties. This paper describes the analyses performed, and the procedure followed in identifying and solving some problems found when building components are tested for UA and gA in a test cell under warm and moderate weather conditions. A window component was tested in a PASLINK test cell at the CIEMAT’s ‘Plataforma Solar de Almería (PSA-CIEMAT)’ in Tabernas (Almería, Spain) and several data sets recorded under quite different weather and test conditions were analysed. First the problems identified when applying the usual test and linear analysis procedures are described. Then hypotheses about the cause of these problems are formulated. Afterwards, strategies followed for testing these hypotheses are described. Once the cause of the problems had been identified, they were fine tuned to find a model for accurate UA and gA estimation. This study demonstrated that nonlinear models, in which long wave radiation is considered as nonlinear effect, yield remarkably better performance than the commonly used linear models, for estimating the component UA and gA values. 相似文献
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Corneo-scleral contact lenses in an uncommon case of keratoconus with high hyperopia and astigmatism
Esteban Porcar Juan Carlos Montalt Enrique España-Gregori Cristina Peris-Martínez 《Contact lens & anterior eye》2017,40(5):351-356
Purpose
To analyse the visual quality achieved by fitting corneo-scleral contact lenses (CScL) in an uncommon case of bilateral keratoconus, high hyperopia and astigmatism.Methods
A 45-year-old man presented for eye examination due to the unsatisfactory quality of his vision wearing soft toric contact lenses. He presented high hyperopia and astigmatism with bilateral keratoconus. He was fitted with CScL to correct his irregular astigmatism and ocular aberrations. A diagnostic trial set was used in the fitting process and he was assessed according to standardised fitting methodology. Visual acuity, corneal topography, biometry and ocular aberrations were evaluated. The follow-up period was 1 year.Results
The best spectacle-corrected visual acuity was 20/32 with +8.00/?4.50 × 30° for the right eye (RE) and 20/25 with +7.75/?2.25 × 120° for the left eye (LE). After CScL fitting, visual acuity was improved to 20/20 and 20/16 for the RE and LE, respectively. The patient wore these contact lenses an average of 13 h a day. The total high order aberrations decreased by approximately 79% in the RE (2.37–0.50 μm) and 47% in the LE (1.04–0.55 μm) after CScL fitting. Visual quality and wearing time were maintained after 1 year wearing CScL. In addition, no adverse ocular effects were found during this period.Conclusion
The present case report describes how the patient had CScL fitted successfully for management of keratoconus with high hyperopia and astigmatism. They provided optimal visual quality, along with prolonged use times and no adverse effects to the cornea. 相似文献7.
Juan Carlos Montalt Esteban Porcar Enrique España-Gregori Cristina Peris-Martínez 《Contact lens & anterior eye》2018,41(4):351-356
Purpose
To assess the visual quality achieved by fitting corneo-scleral contact lenses (CScL) for keratoconus management.Methods
Thirty patients with keratoconus presented to have CScL fitted because of the unsatisfactory visual quality they experienced with their contact lenses or spectacles. The eye examination included visual acuity assessment, anterior eye biomicroscopy, ocular fundus examination, corneal topographic analysis, endothelial-cell count, contrast sensitivity and aberrometry. The fitting process was performed using a diagnostic trial set. Subjective visual quality and comfort, and contact lens wear time were also reported. Patients were monitored for one year.Results
Three patients discontinued CScL wear before one year. Therefore, 27 eyes of 27 patients (19 male and 8 female) participated in this study. The mean age was 36.1?±?13.1 (mean?±?SD)?years. Statistically significant differences were found in logMAR visual acuity between the best spectacle-corrected vision and after CScL fitting (mean?±?SD, 0.23?±?0.30 and 0.00?±?0.14, respectively; p?<?0.001). The total high-order aberrations decreased significantly (55%), and the spatial frequencies of contrast sensitivity all improved to normal range values of the population. Furthermore, high subjective visual quality and comfort ratings, and prolonged usage times (mean?±?SD, 13.44?±?2.38?h a day) were reported. No adverse ocular effects or clinically relevant changes in corneal parameters, visual quality, comfort or usage time were found one year after wearing CScL.Conclusion
This CScL seems to be safe and healthy, providing optimal visual quality, comfort and prolonged usage times in patients with keratoconus. 相似文献8.
Johnny C.-W. Lee Lionel Porcar Simon A. Rogers 《American Institute of Chemical Engineers》2019,65(12):e16797
Stress relaxation from a step strain test provides important information about constituent dynamics, but if a material has experienced a complex shear history, the underlying physics is not straightforward to access. We use recovery rheology and rheo-small-angle neutron scattering to probe the nonlinear dynamics of an entangled wormlike micelle solution by applying step strains after complex shear histories enforced by large-amplitude oscillatory shear (LAOS) flow. We show that a universal relaxation modulus can be obtained from step strain tests with complex shear histories, as long as the modulus is defined in terms of the recoverable strain. The shear and normal stresses, as well as the alignment of micellar Kuhn segments, are shown to be positively correlated with the recoverable strain. We identify re-entanglement of polymeric chains after cessation of LAOS and show that this process occurs over the same timescales as linear-regime stress relaxation. This work, therefore, lays the foundation of how to accurately probe out-of-equilibrium rheology in a consistent manner. 相似文献
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Objective firmness, average pressure and subjective perception in mattresses for the elderly 总被引:1,自引:0,他引:1
For elderly people, the desirable situation of living independently means facing everyday tasks and risks alone [Monk et al., 2006. Towards a practical framework for managing the risks of selecting technology to support independent living. Appl. Ergon. 37, 599-606]. One such task is buying a mattress through the same channels as younger people. Quite short trials (if any) in the store are usually the only basis for choice. Despite the long-term effects a mattress may have on the user, acceptance or rejection largely depends on this extremely short trial experience. This paper aims to cover the salient mechanical aspects of comfort and usability (rolling, getting up). The results should help manufacturers to know if the long-term benefits of their products are perceived in the short term by senior citizen customers. Four mattresses for the elderly chosen from a sample of 17 available on the Spanish market were compared in pairs for short-term effects (1 min pressure with both hands, 1 min sitting, 1 min lying on back, and 1 min lying on side), simulating a store purchasing trial by a group of young and elderly people in terms of differences between perceived firmness, usability (ease of movement) and comfort. The results of these comparisons were correlated to differences in objective properties such as pressure distribution and objective firmness. No differences in perception were found between young and old users. Only two of the four test methods for perceiving mattress firmness were necessary to explain the majority of variance: pressing the surface of the mattress with a part of the body (both hands or buttocks), and contact using the entire body (lying on back or side). A number of significant relationships were found, with the following of note: increments in 'objective firmness' (estimated from test load/deflection) correlate positively to increments in 'perceived firmness'; increments in 'average pressure' (measured using a mannequin) correlate positively to increments (within certain limits) in 'perceived firmness'; increments in 'objective firmness' and in 'average pressure' are associated with increments in 'overall comfort' and with reductions in 'difficulty in rolling". Finally, it was found that people with a higher body mass index tend to be (weak correlation) more sensitive to changes in 'objective firmness'. 相似文献
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Mohammad Shojaaddini María José López Saeid Moharramipour Mahvash Khodabandeh Ali Asghar Talebi Cristina Vilanova Amparo Latorre Manuel Porcar 《Journal of Stored Products Research》2012
After several disease outbreaks in laboratory cultures of pyralid moths in Tabriz University, Iran, during 2004 and 2005, a new Bacillus thuringiensis aizawai strain EF495116 (BTA) was isolated from a dead Plodia interpunctella larva. A complete characterization of the strain was performed, including serological identification, protein and plasmid pattern determination, a PCR-based identification of virulence-related genes, nucleotide sequence analysis of the 16S rDNA and gyrB genes (in order to find out relationships between the species with other virulent Bacillus pathogens), and biological activity assays. These studies revealed that BTA produced a major parasporal protein band of about 135 kDa, bore seven out of the fourteen pyralid-active genes analyzed (cry1Aa, cry1Ab, cry1C, cry1D, cry1I, cry2A and cry9) and was toxic against P. interpunctella and P. xylostella larvae, with LC50 values of 7.13 and 3.1 μg/mL, respectively. Although these features are common among other B. thuringiensis strains active on Lepidoptera, their role in epizootics is uncertain. However, sequence analysis of the 16S rDNA and gyrB genes revealed that BTA clustered with one of the few B. thuringiensis strains identified as a medical isolate. Interestingly, both strains, like many others reported to produce epizootics, belong to serovar aizawai. The implication of serovar or serovar-dependent genes in epizootics is discussed. 相似文献