Percolation Phenomena in Micropore Adsorption: Influence on Single and Multicomponent Adsorption Equilibria

A novel and simple method for determination of micropore network connectivity of activated carbon using liquid phase adsorption is presented in this paper. The method is applied to three different commercial carbons with eight different liquid phase adsorptives as probes. The effect of the pore network connectivity on the prediction of multicomponent adsorption equilibria was also studied. For this purpose, the Ideal Adsorbed Solution Theory (IAST) was used in conjuction with the modified DR single component isotherm. The results of comparison with experimental data show that incorporation of the connectivity, and consideration of percolation processes associated with the different molecular sizes of the adsorptives in the mixture, can improve the performance of the IAST in predicting multicomponent adsorption equilibria.

Development and evaluation of a species diagnostic polymerase chain reaction-restriction fragment-length polymorphism procedure for cryptic members of the Culex sitiens (Diptera : Culicidae) subgroup in Australia and the southwest Pacific

Members of the Culex sitiens subgroup are important vectors of arboviruses, including Japanese encephalitis virus, Murray Valley encephalitis virus and Ross River virus. Of the eight described species, Cx. annulirostris Skuse, Cx. sitiens Wiedemann, and Cx. palpalis Taylor appear to be the most abundant and widespread throughout northern Australia and Papua New Guinea (PNG). Recent investigations using allozymes have shown this subgroup to contain cryptic species that possess overlapping adult morphology. We report the development of a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) procedure that reliably separates these three species. This procedure utilizes the sequence variation in the ribosomal DNA ITS1 and demonstrates species-specific PCR-RFLP profiles from both colony and field collected material. Assessment of the consistency of this procedure was undertaken on mosquitoes sampled from a wide geographic area including Australia, PNG, and the Solomon Islands. Overlapping adult morphology was observed for Cx. annulirostris and Cx. palpalis in both northern Queensland and PNG and for all three species at one site in northwest Queensland.

The first strand transfer reaction of HIV-1 reverse transcription is more efficient in infected cells than in cell-free natural endogenous reverse transcription reactions

Background: In the presence of dNTPs, intact HIV-1 virions are capable of reverse transcribing at least part of their genome, a process known as natural endogenous reverse transcription (NERT). PCR analysis of virion DNA produced by NERT revealed that the first strand transfer reaction (1stST) was inefficient in intact virions, with minus strand (-) strong stop DNA (ssDNA) copy numbers up to 200 times higher than post-1stST products measured using primers in U3 and U5. This was in marked contrast to the efficiency of 1stST observed in single-round cell infection assays, in which (-) ssDNA and U3-U5 copy numbers were indistinguishable. Objectives: To investigate the reasons for the discrepancy in first strand transfer efficiency between intact cell-free virus and the infection process. Study design: Alterations of both NERT reactions and the conditions of cell infection were used to test whether uncoating and/or entry play a role in the discrepancy in first strand transfer efficiency. Results and Conclusions: The difference in 1stST efficiency could not be attributed simply to viral uncoating, since addition of very low concentrations of detergent to NERT reactions removed the viral envelope without disrupting the reverse transcription complex, and these conditions resulted in no improvement in 1stST efficiency. Virus pseudotyped with surface glycoproteins from either vesicular stomatitis virus or amphotrophic murine leukaemia virus also showed low levels of 1stST in low detergent NERT assays and equivalent levels of (-) ssDNA and 1stST in single-round infections of cells, demonstrating that the gp120-mediated infection process did not select for virions capable of carrying out 1stST. These data indicate that a post-entry event or factor may be involved in efficient HIV-1 reverse transcription in vivo. (C) 2002 Elsevier Science B.V. All rights reserved.

Polymerase chain reaction tests for the identification of Ross River, Kunjin and Murray Valley encephalitis virus infections in horses

Objective To develop and validate specific, sensitive and rapid diagnostic tests using RT-PCR for the detection of Ross River virus (RRV), Kunjin virus (KV) and Murray Valley encephalitis virus (MVEV) infections in horses. Methods Primer sets based on nucleotide sequence encoding the envelope glycoprotein E2 of RRV and on the nonstructural protein 5 (NS5) of KV and MVEV were designed and used in single round PCRs to test for the respective viruses in infected cell cultures and, in the case of RRV, in samples of horse blood and synovial fluid. Results The primer pairs designed for each of the three viruses amplified a product of expected size from prototype viruses that were grown in cell culture. The identity of each of the products was confirmed by nucleotide sequencing indicating that in the context used the RT-PCRs were specific. RRV was detected in serums from 8 horses for which there were clinical signs consistent with RRV infection such that an acute-phase serum sample was taken and submitted for RRV serology testing. The RRV RT-PCR was analytically sensitive in that it was estimated to detect as little as 50 TCID50 of RRV per mL of serum and was specific in that the primer pairs did not amplify other products from the 8 serum samples. The RRV primers also detected virus in three independent mosquito pools known to contain RRV by virus isolation in cell culture. Samples from horses suspected to be infected with KV and MVEV were not available. Conclusion Despite much anecdotal and serological evidence for infection of horses with RRV actual infection and associated clinical disease are infrequently confirmed. The availability of a specific and analytically sensitive RT-PCR for the detection of RRV provides additional opportunities to confirm the presence of this virus in clinical samples. The RTPCR primers for the diagnosis of KV and MVEV infections were shown to be specific for cell culture grown viruses but the further validation of these tests requires the availability of appropriate clinical samples from infected horses.

Early pregnancy factor treatment suppresses the inflammatory response and adhesion molecule expression in the spinal cord of SJL/J mice with experimental autoimmune encephalomyelitis and the delayed-type hypersensitivity reaction to trinitrochlorobenzene in normal BALB/c mice

Early pregnancy factor (EPF) is a secreted protein, present in serum during early pregnancy and essential for maintaining viability of the embryo. It is a homologue of chaperonin 10 (Cpn10) but, unlike Cpn10, it has an extracellular role. EPF has immunosuppressive and growth regulatory properties. Previously we have reported the preparation of recombinant EPF (rEPF) and shown that treatment with rEPF will suppress clinical signs of MBP-EAE in Lewis rats and PLP-EAE in SJL/J mice. In the present study, these findings have been extended to investigate possible mechanisms involved in the action of EPF. Following treatment of mice with rEPF from the day of inoculation, there were fewer infiltrating CD3+ and CD4+ cells in the parenchyma of the spinal cord during the onset of disease and after the initial episode, compared with mice treated with vehicle. Expression of the integrins LFA-1, VLA-4 and Mac-1 and of members of the immunoglobulin superfamily of adhesion molecules ICAM-1 and VCAM-1 was suppressed in the central nervous system (CNS) following rEPF treatment. The expression of PECAM-1 was not affected. To determine if rEPF suppressed T cell activation in the periphery, the delayed-type hypersensitivity (DTH) reaction of normal BALB/c mice to trinitrochlorobenzene (TNCB) following treatment with rEPF was studied. The results showed that treatment with rEPF suppressed the DTH reaction, demonstrating the ability of EPF to downregulate the cell-mediated immune response. These results indicate that suppression of immunological mechanisms by rEPF plays a major role in the reduction of clinical signs of disease in experimental autoimmune encephalomyelitis (EAE). (C) 2003 Elsevier Science B.V. All rights reserved.

Analysis of multicomponent adsorption kinetics on activated carbon

An integrated mathematical model for the kinetics of multicomponent adsorption on microporous carbon was developed. Transport in this bidisperse solid is represented by balance equations in the macropore and micropore phases, in which gas-phase diffusion dominates the mass transfer in the macropores, with the phenomenological diffusivities represented by the generalized Maxwell-Stefan (GMS) formulation. Viscous flow also contributes to the macropore fluxes and is included in the MS expressions. Diffusion of the adsorbed phase controls the mass transfer in the micro ore phase, p which is also described in a similar way by the MS method. The adsorption isotherms are represented by a new heterogeneous modified vacancy solution theory formulation of adsorption, which has proved to be a robust method for adsorption on activated carbons. The model is applied to the coadsorption and codesorption of C2H6 and C3H8 on Ajax and Norit carbon, as well as the displacement on Ajax carbon. The effect of the viscous flow in the macropore phase is not significant for the cases studied. The model accurately predicts the overshoot behavior and rollup of C2H6 during coadsorption. The prediction for the heavier compound C3H8 is always satisfactory, though at higher C3H8 mole fraction, the overshoot extent of C2H6 is overpredicted, possibly due to neglect of heat effects.

Effect of pore-network connectivity on multicomponent adsorption of large molecules

The effect of pore-network connectivity on binary liquid-phase adsorption equilibria using the ideal adsorbed solution theory (LAST) was studied. The liquid-phase binary adsorption experiments used ethyl propionate, ethyl butyrate, and ethyl isovalerate as the adsorbates and commercial activated carbons Filtrasorb-400 and Norit ROW 0.8 as adsorbents. As the single-component isotherm, a modified Dubinin-Radushkevich equation was used. A comparison with experimental data shows that incorporating the connectivity of the pore network and considering percolation processes associated with different molecular sizes of the adsorptives in the mixture, as well as their different corresponding accessibility, can improve the prediction of binary adsorption equilibria using the LAST Selectivity of adsorption for the larger molecule in binary systems increases with an increase in the pore-network coordination number, as well with an increase in the mean pore width and in the spread of the pore-size distribution.

Japan and India: soft balancing as a reaction to China's rise?

What are Indian and Japanese reactions to China's rise in economic, political and military terms? According to realist tradition, their option would be between balancing and bandwagoning. Applying Stephen Walt's balance of threats approach, this work aims to analyze Indian and Japan responses to an increasingly powerful China; its conclusions point to an evolving relationship between India and Japan, in military terms, especially after 2005.

Seeing films: audiences reaction to local cultural products

This paper discusses the results of a large survey conducted in 2006 on the perception Portuguese movies’ audiences have of their own locally produced films. Audience’s reception of locally produced films is marked by the rejection of the consumption of these objects as a result of a bias against locally produced cultural artefacts. The prejudice shaping this relationship, not only demands for new cultural and social politics, but also raises a number of questions on local and European media industry’s ability to cope with its own audiences’ expectations. Finally, broader considerations are made on the different ways contemporary audiences are shaping media technologies, and their respective cultural artefacts, through their own use and reception of those technologies and artefacts.

Studies in search of a suitable experimental insect model for xenodiagnosis of hosts with Chagas' disease: 3 - On the interaction of vector species and parasite strain in the reaction of bugs to infection by Trypanosoma cruzi

The reaction of nine vector species of Chagas' disease to infection by seven different Trypanosoma cruzi strains; Berenice, Y, FL, CL, S. Felipe, Colombiana and Gávea, are examined and compared. On the basis of the insects' ability to establish and maintain the infection, vector species could be divided into two distinct groups which differ in their reaction to an acute infection by T. cruzi. While the proportion of positive bugs was found to be low in Triatoma infestans and Triatoma dimidiata it was high, ranging from 96.9% to 100% in the group of wild (Rhodnius neglectus, Triatoma rubrovaria)and essentially sylvatic vectors in process of adaptation to human dwellings, maintained under control following successful insecticidal elimination of Triatoma infestans (Panstrongylus megistus, Triatoma sordida and Triatoma pseudomaculata). An intermediate position is held by Triatoma brasiliensis and Rhodnius prolixus. This latter has been found to interchange between domestic and sylvatic environments. The most important finding is the strikingly good reaction between each species of the sylvatic bugs and practically all T. cruzi strains herein studied, thus indicating that the factors responsible for the excellent reaction of P.megistus to infection by Y strain, as previously reported also come into operation in the reaction of the same vector species to acute infections by five of the remaining T.cruzi strains. Comparison or data reported by other investigators with those herein described form the basis of the discussion of Dipetalogaster maximus as regards its superiority as a xenodiagnostic agent.

Coordination Chemistry of the (eta(6)-p-Cymene)ruthenium(II) Fragment with Bis-, Tris-, andTetrakis(pyrazol-1-yl)borate Ligands: Synthesis, Structural, Electrochemical, and CatalyticDiastereoselective Nitroaldol Reaction Studies

Novel [Ru(eta(6)-p-cymene)(kappa(2)-L)X] and [Ru(eta(6)-p-cymene)(kappa(3)-L)]X center dot nH(2)O complexes (L = bis-, tris-, or tetrakis-pyrazolylborate; X = Cl, N-3, PF6, or CF3SO3) are prepared by treatment of [Ru(eta(6)-p-cymene)Cl-2](2) with poly-(pyrazolyl)borate derivatives [M(L)] (L in general; in detail L = Ph(2)Bp = diphenylbis-(pyrazol-1-yl)borate; L = Tp = hydrotris(pyrazol-1-yl)borate; L = pzTp = tetrakis(pyrazol-1-yl)borate; L = Tp(4Bo) = hydrotris(indazol-1-yl)borate, L = T-p4Bo,T-5Me = (5-methylindazol-1-yl)borate; L = Tp(Bn,4Ph) = hydrotris(3-benzyl-4-phenylpyrazol-1-yl)borate; M = Na, K, or TI) and characterized by analytical and spectral data (IR, ESIMS, H-1 and C-13 NMR). The structures of [Ru(eta(6)-p-cymene)(Ph(2)Bp)Cl] (1) and [Ru(eta(6)-p-cymene)(Tp)Cl] (3) have been established by single-crystal X-ray diffraction analysis. Electrochemical studies allowed comparing the electron-donor characters of Tp and related ligands and estimating the corresponding values of the Lever E-L ligand parameter. The complexes [Ru(eta(6)-p-cymene)-(kappa(2)-L)X] and [Ru(eta(6)-p-cymene)(kappa(3)-L)]X center dot nH(2)O act as catalyst precursors for the diastereoselective nitroaldol reaction of benzaldehyde and nitroethane to the corresponding beta-nitroalkanol (up to 82% yield, at room temperature) with diastereoselectivity toward the formation of the threo isomer.

Analysis of ground reaction force and electromyographic activity of the gastrocnemius muscle during double support

O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).

Comparative analysis of the ground reaction forces, during the support phase, in a group of pregnant women on their 3rd trimester of pregnancy and in a group of not pregnant women

PURPOSE: To analyze and compare the Ground Reaction Forces (GRF), during the stance phase of walking in pregnant women in the 3rd trimester of pregnancy, and non pregnant women. METHODS: 20 women, 10 pregnant and 10 non pregnant, voluntarily took part in this study. GRF were measured (1000 Hz) using a force platform (BERTEC 4060-15), an amplifier (BERTEC AM 6300) and an analogical-digital converter of 16 Bits (Biopac). RESULTS: The study showed that there were significant differences among the two groups concerning absolute values of time of the stance phase. In what concerns to the normalized values the most significant differences were verified in the maximums values of vertical force (Fz3, Fz1) and in the impulse of the antero-posterior force (Fy2), taxes of growth of the vertical force, and in the period of time for the antero-posterior force (Fy) be null. CONCLUSIONS: It is easier for the pregnant to continue forward movement (push-off phase). O smaller growth rates in what concerns to the maximum of the vertical force (Fz1) for the pregnant, can be associated with a slower speed of gait, as an adaptation strategy to maintain the balance, to compensate the alterations in the position of her center of gravity due to the load increase. The data related to the antero-posterior component of the force (Fy), shows that there is a significant difference between the pregnant woman’s left foot and right foot, which accuses a different functional behavior in each one of the feet, during the propulsion phase (TS).

Study on the glycerolysis reaction of high free fatty acid oils for use as biodiesel feedstock

Biodiesel is the main alternative to fossil diesel and it may be produced from different feedstocks such as semi-refined vegetable oils, waste frying oils or animal fats. However, these feedstocks usually contain significant amounts of free fatty acids (FFA) that make them inadequate for the direct base catalyzed transesterification reaction (where the FFA content should be lower than 4%). The present work describes a possible method for the pre-treatment of oils with a high content of FFA (20 to 50%) by esterification with glycerol. In order to reduce the FFA content, the reaction between these FFA and an esterification agent is carried out before the transesterification reaction. The reaction kinetics was studied in terms of its main factors such astemperature, % of glycerin excess, % of catalyst used, stirring velocity and type of catalyst used. The results showed that glycerolysis is a promising pretreatment to acidic oils or fats (> 20%) as they led to the production of an intermediary material with a low content of FFA that can be used directly in thetransesterification reaction for the production of biodiesel. (C) 2011 Elsevier B.V. All rights reserved.

PPO Reaction Scale-up

O óxido de polifenileno com a marca comercial PPO® é uma das resinas principais produzidas na SABIC IP e o ingrediente principal do plástico de engenharia com a marca registada, Noryl®. A equipa de tecnologia de processo de PPO® desenvolve uma série de novos produtos em reactores de pequena escala, tanto em Selkirk como em Bergen op Zoom. Para se efectuar uma transição rápida da escala laboratorial para a fábrica, é necessário um conhecimento completo do reactor. O objectivo deste projecto consiste em esboçar linhas gerais para o scale-up de novos produtos de PPO1, do laboratório para a escala industrial, baseado no estudo de um tipo de PPO, PPO 803. Este estudo pode ser dividido em duas fases. Numa primeira fase, as receitas e os perfis da reacção são comparados, de onde se retiram as primeiras conclusões. Posteriormente, com base nestas conclusões, é realizado um planeamento experimental. O estudo inicial sugeriu que a receita, a temperatura inicial do reactor e a velocidade do agitador poderiam influenciar o tempo da reacção bem como a queda da velocidade intrínseca do polímero (IV drop). As reacções experimentais mostraram que a receita é o principal factor que influencia, tanto o tempo de reacção, como a queda de viscosidade intrínseca. O tempo de reacção será tanto maior quanto menor a agitação devido à má dispersão do oxigénio na mistura. O uso de temperaturas iniciais elevadas conduz a uma queda maior da viscosidade intrínseca devido à desactivação do catalisador. O método experimental utilizado no laboratório de Bergen op Zoom é um bom exemplo, simulador, do procedimento utilizado na fábrica.