952 resultados para Anion pairing


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A monolayer of 1:12 phosphomolybdic anion (PMo_(12)) was modified electrochemically on a glassy carbon electrode and its electrochemical behavior was studied with cyclic voltammetry (CV). It is shown that PMo_(12) film is adsoibed strongly on the surface of glassy carbon electrodes, H~+ ions in the solution plays an important role in the electrochemical processes of PMo_(12) film modified electrodes, whereas other anions, such as Cl~-, NO_3~-, SO_4~(2-), ClO_4~- and PO_4~(3-) etc., do not take par...

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It has been firstly found by means of cyclic voltammetry (CV) and chronopotentiometry with linear current-scanning (CLC)that 12-silicotungstate anion (SiW_(12)O_(40)~(4-)) with high charge numbers, large molecular volume and symmetric structure can cross

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Genomic constitutions of three taxa of Hystrix Moench, H. patula, H. duthiei ssp. duthiei and H. duthiei ssp. longearistata, were examined by meiotic pairing behavior and genomic in-situ hybridization. Meiotic pairing in hybrids of H. patula x Pseudoroegneria spicata (St), H. patula x Elymus wawawaiensis (StH), H. patula x H. duthiei ssp. longearistata, H. patula x Psathyrostachys huashanica (Ns(h)), H. duthiei ssp. duthiei x Psa. huashanica, H. duthiei ssp. longearistata x Psa. huashanica, Leymus multicaulis (NsXm) x H. duthiei ssp. longearistata averaged 6.53, 12.83, 1.32, 0.29, 5.18, 5.11 and 10.47 bivalents per cell, respectively. The results indicate that H. patula has the StH genome and H. duthiei ssp. duthiei and H. duthiei ssp. longearistata have the NsXm genome. Results of genomic in-situ hybridization analysis strongly supported the chromosome pairing data; therefore it is concluded that the type species of Hystrix, H. patula, should be included in Elymus, and that H. duthiei ssp. duthiei and H. duthiei ssp. longearistata should be transferred to Leymus.

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Separation of the acidic compounds in the ion-exchange capillary electrochromatograph (IE-CEC) with strong anion-exchange packing as the stationary phase was studied. It was observed that the electroosmotic flow (EOF) in strong anion-exchange CEC moderately changed with increase of the eluent ionic strength and decrease of the eluent pH, but the acetonitrile concentration in the eluent had almost no effect on the EOF. The EOF in Strong anion-exchange CEC with eluent of low pH value was much larger than that in RP-CEC with Spherisorb-ODS as the stationary phase. The retention of acidic compounds on the strong anion-exchange packing was relatively weak due to only partial ionization of them, and both chromatographic and electrophoretic processes contributed to separation. It was observed that the retention values of acidic compounds decreased with the increase of phosphate buffer and acetonitrile concentration in the eluent as well as the decrease of the applied voltage, and even the acidic compounds could elute before the void time. These factors also made an important contribution to the separation selectivity for tested acidic compounds, which could be separated rapidly with high column efficiency of more than 220 000 plates/m under the optimized separation conditions. (C) 2000 Elsevier Science BN. All rights reserved.

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UPNa. Instituto de Agrobiotecnología. Laboratorio de Biofilms Microbianos.

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Along with the growing demand for cryptosystems in systems ranging from large servers to mobile devices, suitable cryptogrophic protocols for use under certain constraints are becoming more and more important. Constraints such as calculation time, area, efficiency and security, must be considered by the designer. Elliptic curves, since their introduction to public key cryptography in 1985 have challenged established public key and signature generation schemes such as RSA, offering more security per bit. Amongst Elliptic curve based systems, pairing based cryptographies are thoroughly researched and can be used in many public key protocols such as identity based schemes. For hardware implementions of pairing based protocols, all components which calculate operations over Elliptic curves can be considered. Designers of the pairing algorithms must choose calculation blocks and arrange the basic operations carefully so that the implementation can meet the constraints of time and hardware resource area. This thesis deals with different hardware architectures to accelerate the pairing based cryptosystems in the field of characteristic two. Using different top-level architectures the hardware efficiency of operations that run at different times is first considered in this thesis. Security is another important aspect of pairing based cryptography to be considered in practically Side Channel Analysis (SCA) attacks. The naively implemented hardware accelerators for pairing based cryptographies can be vulnerable when taking the physical analysis attacks into consideration. This thesis considered the weaknesses in pairing based public key cryptography and addresses the particular calculations in the systems that are insecure. In this case, countermeasures should be applied to protect the weak link of the implementation to improve and perfect the pairing based algorithms. Some important rules that the designers must obey to improve the security of the cryptosystems are proposed. According to these rules, three countermeasures that protect the pairing based cryptosystems against SCA attacks are applied. The implementations of the countermeasures are presented and their performances are investigated.

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The tris[tetrachlorobenzenediolato]phosphate(v) anion (TRISPHAT) is known to be an efficient NMR chiral shift agent for various chiral cationic species. Here we compare the efficiency of TRISPHAT and of a chiral lanthanide shift reagent for the determination of the enantiomeric purity of the chiral building block [Ru(phen)[2]PY[2]][2][+] which possesses C[2] symmetry. We also discuss our results in terms of the geometry of interaction between the Ru(II) complex and the TRISPHAT anion.

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Knowing one's HIV status is particularly important in the setting of recent tuberculosis (TB) exposure. Blood tests for assessment of tuberculosis infection, such as the QuantiFERON Gold in-tube test (QFT; Cellestis Limited, Carnegie, Victoria, Australia), offer the possibility of simultaneous screening for TB and HIV with a single blood draw. We performed a cross-sectional analysis of all contacts to a highly infectious TB case in a large meatpacking factory. Twenty-two percent were foreign-born and 73% were black. Contacts were tested with both tuberculin skin testing (TST) and QFT. HIV testing was offered on an opt-out basis. Persons with TST >or=10 mm, positive QFT, and/or positive HIV test were offered latent TB treatment. Three hundred twenty-six contacts were screened: TST results were available for 266 people and an additional 24 reported a prior positive TST for a total of 290 persons with any TST result (89.0%). Adequate QFT specimens were obtained for 312 (95.7%) of persons. Thirty-two persons had QFT results but did not return for TST reading. Twenty-two percent met the criteria for latent TB infection. Eighty-eight percent accepted HIV testing. Two (0.7%) were HIV seropositive; both individuals were already aware of their HIV status, but one had stopped care a year previously. None of the HIV-seropositive persons had latent TB, but all were offered latent TB treatment per standard guidelines. This demonstrates that opt-out HIV testing combined with QFT in a large TB contact investigation was feasible and useful. HIV testing was also widely accepted. Pairing QFT with opt-out HIV testing should be strongly considered when possible.

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info:eu-repo/semantics/published