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41.
Using the fact that the Parikh matrix mapping is not an injective mapping, the paper investigates some properties of the set of words with the same Parikh matrix; these words are called “amiable”. The presented results extend the results obtained in [A. Atanasiu, Binary amiable words, Int. J. Found. Comput. Sci. 18 (2) (2007) 387–400] for the binary case. In particular it is shown that all the words having the same Parikh matrix can be obtained one from another by applying only two types of transformations. Moreover, the mirrors of two amiable words are also amiable (thus forming a symmetrical class of words). 相似文献
42.
The role of two central residues (K68, E69) of the fourth hypervariable loop of the Valpha domain (HV4alpha) in antigen recognition by an MHC class II-restricted T cell receptor (TCR) has been analyzed. The TCR recognizes the NH2-terminal peptide of myelin basic protein (Ac1-11, acetylated at NH2 terminus) associated with the class II MHC molecule I-Au. Lysine 68 (K68) and glutamic acid 69 (E69) of HV4alpha have been mutated both individually and simultaneously to alanine (K68A, E69A). The responsiveness of transfectants bearing wild-type and mutated TCRs to Ac1-11-I-Au complexes has been analyzed in the presence and absence of expression of the coreceptor CD4. The data demonstrate that in the absence of CD4 expression, K68 plays a central role in antigen responsiveness. In contrast, the effect of mutating E69 to alanine is less marked. CD4 coexpression can partially compensate for the loss of activity of the K68A mutant transfectants, resulting in responses that, relative to those of the wild-type transfectants, are highly sensitive to anti-CD4 antibody blockade. The observations support models of T cell activation in which both the affinity of the TCR for cognate ligand and the involvement of coreceptors determine the outcome of the T cell-antigen-presenting cell interaction. 相似文献
43.
An EMI estimate for shielding-enclosure evaluation 总被引:7,自引:0,他引:7
Min Li Drewniak J.L. Radu S. Nuebel J. Hubing T.H. DuBroff R.E. van Doren T.P. 《Electromagnetic Compatibility, IEEE Transactions on》2001,43(3):295-304
A relatively simple, closed-form expression has been developed to estimate the EMI from shielding enclosures due to coupling from interior sources through slots and apertures at the enclosure cavity modes. A power-balance method, Bethe's (1944) small-hole theory, and empirically developed formulas for the relation between radiation, and slot length and number of slots, were employed to estimate an upper bound on the radiated EMI from shielding enclosures. Comparisons between measurements and estimated field strengths suitably agree within engineering accuracy 相似文献
44.
Bogdan Bucur Gabriel Lucian Radu Constantin Nicolae Toader 《European Food Research and Technology》2008,226(6):1335-1342
A portable bienzymatic analytical system was developed for the chronoamperometric analysis of methanol–ethanol mixtures. The
system consists of two biosensors, one based on alcohol dehydrogenase (ADH) that responds only to the ethanol and the second
one based on alcohol oxidase (AOX) that responds to both methanol and ethanol. The transducers were screen-printed electrodes
(SPEs) modified with mediators: Meldola blue for ADH and Co-phthalocyanine for AOX. The calibration graph of the ADH biosensor
is linear between 0.3 and 8 mmol/L ethanol. The AOX biosensor is able to quantify both analytes in mixtures that contain methanol
between 3 and 70 mmol/L and ethanol ranging from 15 to 110 mmol/L. Interferences due to non-specific oxidations from common
oxidizable compounds like gallic acid and ascorbic acid were smaller in the case of transducer based on Meldola blue. The
analytical system was successfully tested on real samples: non-alcoholised beer (NAB) spiked with ethanol or methanol and
a falsified rose wine (FRW). 相似文献
45.
Placement of Substrate Contacts to Minimize Substrate Noise in Mixed-Signal Integrated Circuits 总被引:1,自引:0,他引:1
Radu M. Secareanu Scott Warner Scott Seabridge Cathie Burke Thomas E. Watrobski Christopher Morton William Staub Thomas Tellier Eby G. Friedman 《Analog Integrated Circuits and Signal Processing》2001,28(3):253-264
The placement of substrate contacts in epi and non-epi technologies is analyzed in order to control and reduce the substrate noise amplitude and spreading. The choice of small or large substrate contacts or rings for each of the two major technologies is highlighted. Design guidelines for placing substrate contacts so as to improve the noise immunity of digital circuits in mixed-signal smart-power systems are also presented. 相似文献
46.
Prevalence and resistance to antibiotics for Aeromonas species from retail fish in Malaysia 总被引:1,自引:0,他引:1
A total of 87 market fish samples representing five types of fish were evaluated for the presence of Aeromonas spp. Of the samples examined, 69%, 55%, 11.5% and 2.3% harbored Aeromonas spp., A. veronii biovar sobria, A. hydrophila and A. caviae, respectively. The 60 isolated Aeromonas spp. strains were further examined for hemolytic activity, resistance to antimicrobial agents and presence of plasmids. Hemolytic activity varied widely among the isolated strains. Though all the isolates demonstrated resistance to three or more of the antibiotics tested, all were susceptible to ceptazidime. Thirty-four (56.7%) of the sixty isolates harbored plasmids, with sizes ranging from 2.3 to 15.7 kb. These results indicate that hemolytic, multiple antibiotic resistant and genetically diverse aeromonads are easily recovered from fish in this region. 相似文献
47.
Bactenecin 5 (Bac 5), a cationic antibacterial peptide, contains a repeating region of Arg-Pro-Pro-X (X = hydrophobic residue). To investigate the structure and property of a Pro/Arg-rich region, we synthesized a series of repeating peptides, Ac-(Arg-Pro-Pro-Phe)n-NHCH3 (n = 2, 4, 6, 8 and 10) (PR2, PR4, PR6, PR8 and PR10) as models. The circular dichroism (CD) study suggested that the peptides with longer repeats, PR6, PR8 and PR10, formed a conformation similar to poly(proline)-II in aqueous solution. The CD spectra did not change in the presence of dipalmitoyl-DL-alpha-phosphatidylcholine (DPPC), but they changed in the presence of DPPC/ dipalmitoyl-DL-3-phosphatidylglycerol (DPPG). The gamma-helix, which is very similar in conformation to the poly(proline)-II helix, had the lowest energy conformation for the peptides by energy calculations. Peptides PR6, PR8 and PR10 caused slight leakage of fluorescent dye entrapped in DPPC vesicles, and in the presence of DPPC/DPPG, these peptides showed a considerable level of dye-leakage activity. In contrast, the shorter peptides PR2 and PR4 showed no activity. The same tendency was found in measurements of membrane-fusion activity. Judging from these results, the repeating region of Bac 5 may make a framework to hold a conformation resembling the poly(proline)-II structure in aqueous solution. In addition, this region may interact with acidic lipids, resulting in a change in conformation of the peptide. 相似文献
48.
Jianu R Demiralp Ç Laidlaw DH 《IEEE transactions on visualization and computer graphics》2012,18(6):978-987
We introduce two-dimensional neural maps for exploring connectivity in the brain. For this, we create standard streamtube models from diffusion-weighted brain imaging data sets along with neural paths hierarchically projected into the plane. These planar neural maps combine desirable properties of low-dimensional representations, such as visual clarity and ease of tract-of-interest selection, with the anatomical familiarity of 3D brain models and planar sectional views. We distribute this type of visualization both in a traditional stand-alone interactive application and as a novel, lightweight web-accessible system. The web interface integrates precomputed neural-path representations into a geographical digital-maps framework with associated labels, metrics, statistics, and linkouts. Anecdotal and quantitative comparisons of the present method with a recently proposed 2D point representation suggest that our representation is more intuitive and easier to use and learn. Similarly, users are faster and more accurate in selecting bundles using the 2D path representation than the 2D point representation. Finally, expert feedback on the web interface suggests that it can be useful for collaboration as well as quick exploration of data. 相似文献
49.
This study is focused on structural modifications of leptomeninges and cerebral matter in children deceased because of iatrogenic AIDS. Although we do not evidence the specific lesions of AIDS, we have noticed edema, hyperemia, hematic extravasation, microlesions of the small vessel walls, perivascular infiltrations with lymphocytes, macrophages and even plasmocytes, moderate tigrolysis, mild demyelination, gliosis and sidero-calcic deposits. We do not consider these lesions as specific to HIV-infected patients. 相似文献
50.
Antonio Radoi Alexandru Cosmin Obreja Sandra A. V. Eremia Adina Bragaru Adrian Dinescu Gabriel-Lucian Radu 《Journal of Applied Electrochemistry》2013,43(10):985-994
Pristine graphene platelets and graphene oxide were used as electrode modifiers, aiming the investigation of their electrochemical efficacy towards β-nicotinamide adenine dinucleotide (NADH). The electrochemical detection of NADH is one of the most studied areas of bioelectroanalysis because of the ubiquity of NAD(P)H-based enzymatic reactions in nature. Commercially available graphene and laboratory prepared graphene oxide were used to modify glassy carbon electrodes and the behaviour of such modified electrodes against potassium ferricyanide (III) and NADH was reported. Relying on the graphene-modified transducer, l-lactic dehydrogenase (l-LDH) was successfully immobilised in a 1 % Nafion® membrane. The developed biosensor, working at +250 mV versus Ag/AgCl reference electrode, was used to assess l-lactic acid in four different types of yogurts, revealing an l-lactic acid concentration ranging between 0.3 and 0.6 %. 相似文献