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61.
Naturally contaminated beef-brisket fat showed a psychrotroph count of 4 × 10(9) CFU/cm(2) after 14 days of aerobic refrigerated storage (5°C ± 1°C). Pseudomonas was the predominating genus. Other micro-organisms, such as Enterobacteriaceae and Brochothrix thermosphacta, grew up to 2·5 × 10(8) cfu/cm(2) and 1·6 × 10(8) cfu/cm(2), respectively. Concentrations of different substrates that could support microbial growth were measured. Glucose concentration dropped to approximately one-third of the initial level during the first week of storage. Lactic acid also declined. Free fatty acids increased significantly (P < 0·05) during refrigeration. However, other lipid-deterioration indices, such as the thiobarbituric acid number and the peroxide value, remained unchanged. Beef subcutaneous fat had a high initial microbial load and a capacity to support extensive bacterial growth. It may therefore constitute an important source of contamination for meat and manufactured meat products. 相似文献
62.
Faisal Ahmed Carlos Rodríguez-Fernández Henry A. Fernandez Yi Zhang Abde Mayeen Shafi Md Gius Uddin Xiaoqi Cui Hoon Hahn Yoon Naveed Mehmood Andreas C. Liapis Lide Yao Humeyra Caglayan Zhipei Sun Harri Lipsanen 《Advanced functional materials》2023,33(33):2302051
Developing selective and coherent polymorphic crystals at the nanoscale offers a novel strategy for designing integrated architectures for photonic and optoelectronic applications such as metasurfaces, optical gratings, photodetectors, and image sensors. Here, a direct optical writing approach is demonstrated to deterministically create polymorphic 2D materials by locally inducing metallic 1T′-MoTe2 on the semiconducting 2H-MoTe2 host layer. In the polymorphic-engineered MoTe2, 2H- and 1T′- crystalline phases exhibit strong optical contrast from near-infrared to telecom-band ranges (1–1.5 µm), due to the change in the band structure and increase in surface roughness. Sevenfold enhancement of third harmonic generation intensity is realized with conversion efficiency (susceptibility) of ≈1.7 × 10−7 (1.1 × 10−19 m2 V−2) and ≈1.7 × 10−8 (0.3 × 10−19 m2 V−2) for 1T′ and 2H-MoTe2, respectively at telecom-band ultrafast pump laser. Lastly, based on polymorphic engineering on MoTe2, a Schottky photodiode with a high photoresponsivity of 90 AW−1 is demonstrated. This study proposes facile polymorphic engineered structures that will greatly benefit realizing integrated photonics and optoelectronic circuits. 相似文献
63.
A. Rodríguez Juárez H. Hernández Cocoletzi J. F. Sánchez Ramírez 《Fullerenes, Nanotubes and Carbon Nanostructures》2017,25(12):716-725
In this work are studied the electronic and structural properties of armchair boron nitride/carbon nanotubes using first principles calculations. The density functional within the generalized gradient approximation (HSEh1PBE-GGA) is used. For each composition, different bonding schemes for the construction of the hybrid systems were employed. Among them, structural stability with neutral charge was determined for the following compositions: T1: B40N35C75H20, T2: B35N40C75H20, T3: B37N38C75H20, T4 : B37N37C76H20, and T7: B35N35C80H20. All these hybrid nanotubes have high polarity; the T3, T4 and T7 are semiconductors: whereas T1 and T2 are conductor in character. The formers also have magnetic behavior. These properties together with a low-chemical potential suggest applications as nano-vehicle for drug delivery. These mixed nanotubes also have potential applications in the electronic devices based on the small work function. 相似文献
64.
Thermal Scanning at the Cellular Level by an Optically Trapped Upconverting Fluorescent Particle
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65.
66.
J Rodríguez-Espinosa C Otal-Entraigas N Gascón-Roche J Mora-Brugués E Urgell-Rull JR Bordás-Serrat P Viscasillas-Molins 《Canadian Metallurgical Quarterly》1998,36(12):969-974
Mouse strains congenic for individual quantitative trait loci (QTLs) conferring hypnotic sensitivity to ethanol were constructed by backcrossing genotypically selected ILS x ISS N2 individuals to either inbred Long Sleep (ILS) or inbred Short Sleep (ISS) mice. We used a novel "speed congenic" approach in which N2 mice were genotyped for markers flanking each of the five originally identified QTLs. Genotypic selection for ISS regions at four of the five QTLs, and for ILS/ISS at the fifth QTL, allowed rapid fixation of the genetic background. We call this strategy "QTL-Marker-Assisted Counter Selection" or QMACS. By the N4 generation, phenotypic assessments showed that in some sublines the QTL had not been captured; these sublines were discarded and positive lines split to create new replicate sublines. One QTL, on Chromosome (Chr) 8, was not confirmed. At the N8, virtually all sublines on the remaining QTLs retained the phenotypic difference between heterozygotes and ISS homozygotes. Small numbers of interim congenics were produced at the N6 and later generations in which the ILS QTL was made homozygous on the ISS background; as expected, these congenic mice showed an increased sleep time. For later backcrosses (after the N4), the parents were selected on the basis of phenotype as well as genotype. The parent-offspring correlation over all QTLs was significant, supporting the use of phenotypic selection in congenic construction. 相似文献
67.
S. Rodríguez C. Lafuente J. A. Carrión F. M. Royo J. S. Urieta 《International Journal of Thermophysics》1996,17(6):1281-1288
Excess Volumes,V
E, and excess viscosities,
E, at 293.15 and 313.15 K are reported for binary mixtures of some cyclic ethers (tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran and 2,5-dimethyltetrahydrofuran) + bromocyclohexane. These properties were obtained from density and viscosity measurements.
E and
E show negatives values for all the mixtures. 相似文献
68.
J. A. González S. Feliú P. Rodríguez E. Ramírez C. Alonso C. Andrade 《Materials and Structures》1996,29(1):40-46
It is widely accepted that concrete-embedded steel is in a passive state. However, there are some exceptional circumstances that induce corosion in an active state within concrete structures, thereby severely reducing their durability. This two-part paper analyses some major questions which, however elementary they may be, are still controversial in scientific, technical and economic terms. The first part provides answers to the following questions on the steel/concrete/environment system:
- How does steel in concrete normally behave?
- What are the initiating factors for depassivation?
- What are the effects of corrosion?
- What is the morphology of corrosion in the active state? and
- What is the corrosion rate threshold above which the durability of reinforced concrete structures is impaired? The answers to these questions are provided in light of experimental results, most of which were obtained by the authors themselves.
69.
70.
In this paper we introduce a minimax model unifying several classes of single facility planar center location problems. We
assume that the transportation costs of the demand points to the serving facility are convex functions {Q
i
}, i=1,…,n, of the planar distance used. Moreover, these functions, when properly transformed, give rise to piecewise quadratic functions
of the coordinates of the facility location. In the continuous case, using results on LP-type models by Clarkson (J. ACM 42:488–499,
1995), Matoušek et al. (Algorithmica 16:498–516, 1996), and the derandomization technique in Chazelle and Matoušek (J. Algorithms 21:579–597, 1996), we claim that the model is solvable deterministically in linear time. We also show that in the separable case, one can
get a direct O(nlog n) deterministic algorithm, based on Dyer (Proceedings of the 8th ACM Symposium on Computational Geometry, 1992), to find an optimal solution. In the discrete case, where the location of the center (server) is restricted to some prespecified
finite set, we introduce deterministic subquadratic algorithms based on the general parametric approach of Megiddo (J. ACM
30:852–865, 1983), and on properties of upper envelopes of collections of quadratic arcs. We apply our methods to solve and improve the complexity
of a number of other location problems in the literature, and solve some new models in linear or subquadratic time complexity. 相似文献