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1. Migration into local populations may increase the likelihood of persistence but emigration may decrease the persistence of small and isolated populations. The dispersal behaviour of a day-flying moth Zygaena filipendulae was examined to determine whether emigration is correlated positively or negatively with population size and host plant density. 2. A mark–release–recapture study showed that most moths moved small distances ( 100 m. 3. Twenty-five individuals moved between populations, a measured exchange rate of 8%. Moths were more likely to move between patches that were close together and they moved to relatively large patches. 4. The fraction of residents increased with increasing population size in the patch and increasing host plant cover. Relatively high proportions of individuals left small patches with small moth populations. 5. Moths released in grassland lacking Lotus corniculatus (the host plant) tended to leave the area and biased their movement towards host plant areas, whereas those released within an area containing L. corniculatus tended to stay in that area. 6. Biased movement away from small populations and areas of low host plant density (normally with low population density) was found. This migration-mediated Allee effect is likely to decrease patch occupancy in metapopulations, the opposite of the rescue effect. The effects on metapopulation persistence are not known.

The isotropic phase isolated from a thermally treated coal-tar pitch was studied as a possible precursor for carbon fibres. Extraction with different solvents was performed in order to increase its softening point and so enable higher stabilisation temperatures to be used, with a significant reduction in time. The extraction conditions were selected studying the softening temperatures of the residues, the results of their thermogravimetric analysis and reactivity in air studied by means of differential scanning calorimetry. The residue obtained with a mixture of 40% acetone–60% acetonitrile was found to be the most suitable precursor for the fibres. The carbonised fibres showed a homogeneous surface and diameter, and had tensile properties comparable to other isotropic fibres described in the literature.

Although non-human adenoviruses (AdVs) might offer solutions to problems posed by human AdVs as therapeutic vectors, little is known about their basic biology. In particular, there are no structural studies on the complete virion of any AdV with a non-mammalian host. We combine mass spectrometry, cryo-electron microscopy, and protein crystallography to characterize the composition and structure of a snake AdV (SnAdV-1, Atadenovirus genus). SnAdV-1 particles contain the genus-specific proteins LH3, p32k, and LH2, a previously unrecognized structural component. Remarkably, the cementing protein LH3 has a trimeric β helix fold typical of bacteriophage host attachment proteins. The organization of minor coat proteins differs from that in human AdVs, correlating with higher thermostability in SnAdV-1. These findings add a new piece to the intriguing puzzle of virus evolution, hint at the use of cell entry pathways different from those in human AdVs, and will help development of new, thermostable SnAdV-1-based vectors.

Adenoviruses are non-enveloped icosahedral viruses with trimeric fibre proteins protruding from their vertices. There are five known genera, from which only Mastadenoviruses have been widely studied. Apart from studying adenovirus as a biological model system and with a view to prevent or combat viral infection, there is a major interest in using adenovirus for vaccination, cancer therapy and gene therapy purposes. Adenoviruses from the Atadenovirus genus have been isolated from squamate reptile hosts, ruminants and birds and have a characteristic gene organization and capsid morphology. The carboxy-terminal virus-distal fibre head domains are likely responsible for primary receptor recognition. We determined the high-resolution crystal structure of the Snake Adenovirus 1 (SnAdV-1) fibre head using the multi-wavelength anomalous dispersion (MAD) method. Despite the absence of significant sequence homology, this Atadenovirus fibre head has the same beta-sandwich propeller topology as other adenovirus fibre heads. However, it is about half the size, mainly due to much shorter loops connecting the beta-strands. The detailed structure of the SnAdV-1 fibre head and other animal adenovirus fibre heads, together with the future identification of their natural receptors, may lead to the development of new strategies to target adenovirus vectors to cells of interest.

The proliferation of novel types and designs of electrochemical capacitors makes it necessary to obtain a better understanding of the behavior of these systems together with a more systematic classification of them. In this study a rational classification of supercapacitors based on the charge storage mechanism and the active material of each electrode is proposed. The internationally accepted terminology – the terms symmetric, asymmetric and hybrid – is also clarified in an attempt to standardize the current definitions and facilitate the systematic classification of each device. Additionally, the selection of suitable mathematical expressions to calculate the capacitance of each kind of system is rationalized throughout the discussion taking into account the behavioral characteristics of each electrode. An examination of the potential evolution profile of each electrode during the galvanostatic cycling of the supercapacitor is presented as a key tool for understanding the fundamental behavior of these devices.

Although adenoviruses (AdVs) have been found in a wide variety of reptiles, including numerous squamate species, turtles, and crocodiles, the number of reptilian adenovirus isolates is still scarce. The only fully sequenced reptilian adenovirus, snake adenovirus 1 (SnAdV-1), belongs to the Atadenovirus genus. Recently, two new atadenoviruses were isolated from a captive Gila monster ( Heloderma suspectum ) and Mexican beaded lizards ( Heloderma horridum ). Here we report the full genomic and proteomic characterization of the latter, designated lizard adenovirus 2 (LAdV-2). The double-stranded DNA (dsDNA) genome of LAdV-2 is 32,965 bp long, with an average G+C content of 44.16%. The overall arrangement and gene content of the LAdV-2 genome were largely concordant with those in other atadenoviruses, except for four novel open reading frames (ORFs) at the right end of the genome. Phylogeny reconstructions and plesiomorphic traits shared with SnAdV-1 further supported the assignment of LAdV-2 to the Atadenovirus genus. Surprisingly, two fiber genes were found for the first time in an atadenovirus. After optimizing the production of LAdV-2 in cell culture, we determined the protein compositions of the virions. The two fiber genes produce two fiber proteins of different sizes that are incorporated into the viral particles. Interestingly, the two different fiber proteins assemble as either one short or three long fiber projections per vertex. Stoichiometry estimations indicate that the long fiber triplet is present at only one or two vertices per virion. Neither triple fibers nor a mixed number of fibers per vertex had previously been reported for adenoviruses or any other virus. IMPORTANCE Here we show that a lizard adenovirus, LAdV-2, has a penton architecture never observed before. LAdV-2 expresses two fiber proteins—one short and one long. In the virion, most vertices have one short fiber, but a few of them have three long fibers attached to the same penton base. This observation raises new intriguing questions on virus structure. How can the triple fiber attach to a pentameric vertex? What determines the number and location of each vertex type in the icosahedral particle? Since fibers are responsible for primary attachment to the host, this novel architecture also suggests a novel mode of cell entry for LAdV-2. Adenoviruses have a recognized potential in nanobiomedicine, but only a few of the more than 200 types found so far in nature have been characterized in detail. Exploring the taxonomic wealth of adenoviruses should improve our chances to successfully use them as therapeutic tools.

Ionic conductivity and capacitance measurements are widely used methods for evaluating the desalination efficiency in capacity deionization processes. In this study, these methods are revised and several problems associated to them are identified and evaluated. Furthermore, a new method based on the determination of the chloride ion concentration by means of a chloride selective electrode is proposed as a more reliable alternative for evaluating the desalination performance in these systems. This method has been shown not only to be precise in a wide range of salt concentrations but also to be independent of pH, one of the main limitations of the determinations based on ionic conductivity measurements., The authors thank MICINN and the European Union (project MAT2010-20601-C02-01) for the financial support provided. Patricia Díaz thanks MICINN for a FPI predoctoral research grant (FPI: BES-2011-045394).

An industrial anthracene oil (AO) was polymerized by thermal treatment with the aid of AlCl3, sulphur and air. The composition of the reaction products was investigated by size exclusion chromatography (SEC) and synchronous UV-fluorescence spectroscopy. The SEC profiles show significant differences in the composition of the polymerized products. This suggests that the reactivity of the AO components and the mechanisms of polymerization are different. With sulphur and air, the polymerization involves a low number of AO components, which selectively react to form intermediate and large polymers. AlCl3 causes a more extensive polymerization, giving rise to a product in which the fraction of oligomers of intermediate size (500–700 u) is predominant. Synchronous UV-fluorescence spectroscopy corroborates and supports the SEC results.

The pyrolysis and combustion behaviour of a set of 11 Canadian coals with different ranks (lignite to low volatile bituminous) and maceral compositions has been investigated by TGA techniques. Temperature programmed heating of the coals was carried out both under nitrogen and under air, and the weight loss rates occurring in the two experimental conditions were compared in the whole temperature range studied (100–1000°C). Results showed that the pyrolysis curves of the coals do not match at all with any specific feature of the corresponding combustion profiles, and that the temperatures of initiation of both processes are very different in the low-rank end (higher initiation temperatures for pyrolysis), to become similar only for coal ranks of ∼0.8% vitrinite reflectance and above. This contradicts existing theories which state that coal combustion under TGA conditions is a three-stage process, namely volatiles release, vitrinite combustion and inertinite combustion. The processes leading to the weight loss rates occurring in the early stages of combustion were also investigated, with special emphasis in the temperature interval where no substantial weight losses had occurred yet in either a combustion or a pyrolysis experiment. This was done by heating the coals to 300°C in the TGA under air, and then switching the gas flow to nitrogen and allowing the sample to further devolatilise until 1000°C. Also, partly burnt and/or pyrolysed samples were obtained from the TGA and characterised by optical microscopy techniques. It was observed that the volatile yields of all the coals were substantially reduced as a consequence of their initial heating under air. Besides, evidences of melting and thermal annealing in the inner core of burning coal particles were noticed to occur at lower temperatures than in pyrolysing particles. This was attributed to a sealing effect of the oxidation rim formed in the early stages of combustion, which might give rise to a higher pressure build-up in the inner part of burning particles, thus enhancing the likelihood for condensation reactions to take place in the newly formed metaplast. As combustion profiles are commonly used to infer about combustion behaviour of coals, much care should be exercised in interpreting them, since even in a pure vitrain, two rather than one single material will be involved in the measured weight losses, and, more, these materials will often display fairly different reactivities.

Eight parent samples, obtained from a commercial anthracene oil by air-blowing under different conditions, were thermally treated in nitrogen between 350 and 390°C for 3–8 h. Changes in the composition, pyrolysis behaviour and microstructure of the resultant cokes were studied by standard procedures (i.e. elemental analysis, softening point, etc.), Fourier transformed infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis, mass spectrometry and optical microscopy. The results show that thermal treatment causes the removal of hydrogen (mainly aliphatic) and a considerable amount of the oxygenated functionalities created during the air-blowing treatment. As a result, H 2 O, CO and CO 2 are removed and new C–C bonds are formed producing larger molecules with a higher degree of condensation. Consequently, the toluene insolubles, softening point and carbon yield of the treated samples substantially increase their values. Thermal treatment also improves the quality of samples as carbon precursors and increases graphitisability and resistance of the derived cokes to oxidation.

Multispecies metapopulation models generally make the assumption that the interacting species occupy the same habitat network as one another. We examined the spatial distribution, metapopulation structure, and habitat network of four lepidopteran herbivores feeding on a single host plant, Lotus corniculatus, in a patchy landscape in North Wales, UK. The four species showed contrasting spatial distributions despite the fact that they feed on the same host plant. Information on dispersal rates and population turnover suggest that each species is likely to exhibit metapopulation dynamics, but with different relative contributions of local and regional processes. Detailed analyses of habitat requirements suggest that habitat networks were species-specific, and their degree of occupancy a function of the number of patches in the system. These results do not support the idea that patchiness promotes regional coexistence through multispecies metapopulation dynamics. Rather, each species appeared to act as a largely independent metapopulation system in its own specific habitat network. The results also suggest that conservation recommendations must be based on detailed analysis of the requirements of each key species in order to understand their spatial dynamics.

Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used to assess the oxidative stabilisation of carbonaceous mesophase obtained from a heat-treated coal-tar pitch. Furthermore, the pyrolysis behaviour and air reactivity of stabilised samples were also studied. The stabilisation was performed at 1°C min −1 using two different temperature/time profiles: (i) from 150 to 225°C (A-Series); and (ii) from 200 to 300°C (B-Series). Results showed that oxidative stabilisation involves a dehydrogenative process, with an initial oxygen uptake (weight gain) and a weight loss due to the distillation of light mesophase compounds and the release of gases (e.g. CO, CO 2 and H 2 O). The weight lost by the mesophase is much lower when the temperature/time stabilisation profile is carried out using air instead of nitrogen. This is because oxygen causes the polymerisation of some of the mesophase components, which are distilled when using nitrogen. Information obtained by TG and DSC concerning the temperature range of weight loss suggests that 225 and 250°C are the most appropriate temperatures for the stabilisation of the carbonaceous mesophase under the experimental conditions used in this study.

The pyrolysis behaviour of pitches depends on their chemical composition which in turn depends on the processing conditions used in their preparation. When used as a precursor of carbon matrix composites, pitches are very often pre-treated (air-blowing, thermal treatment) to improve their properties and consequently those of the final material. The pyrolysis behaviour of treated pitches can be very different to that of the parent pitches, and it can also vary when mixed with different types of carbons for the preparation of composites. This work deals with the pyrolysis behaviour of four pitches of very different characteristics (a commercial impregnating pitch, an air-blown pitch and two pitches obtained by thermal treatment) when they are mixed with four granular carbons (anthracite, petroleum coke, foundry coke and graphite). The thermal analysis (TG/DTG and DSC) of pitches and pitch/carbon systems, optical microscopy and the toluene insoluble content of their pyrolysis products are used to monitor possible interactions between the two components during pyrolysis.

Three unidirectional C/C composites were prepared from PAN-based carbon fibres and three coal-tar pitches obtained from the same parent coal-tar pitch but differing in their primary QI content. The effect of the amount of primary QI present in pitches on the air reactivity of pitch-cokes and C/C composites was studied by thermogravimetric analysis. The oxidation of pitch-cokes was performed at 10°C min −1 up to 1000°C. The air reactivity of C/C composites was assessed from the weight loss curves obtained under isothermal conditions in the temperature range of 500 to 575°C for 4 h. The topography of the oxidized composites was examined by scanning electron microscopy. The results showed that pitch-cokes were more reactive than carbon fibres because the presence of QI particles increased their reactivity. With the increase of primary QI content in the pitches, C/C composites showed a higher percentage of carbon matrix, with a finer optical texture, fewer microcracks and less closed porosity. The air reactivity of the composites was affected by both chemical and physical factors, the extent of oxidation determining which of these exerted the greater influence. At low conversions the reactivity was decided by both QI content and the optical texture of the matrix. At high conversions the porosity of the composite was the determining factor.

In this study a set of 10 coals varying in rank and maceral composition has been devolatilised in a flat flame burner at 1000 and 1300°C in order to investigate the changes in char reactivity and structure as a function of pyrolysis temperature. The intrinsic reactivity of the chars, measured isothermally in a thermobalance at 500°C, has been related to the petrographic characteristics of the chars and their CO2 surface areas. The temperature of pyrolysis has shown to have a strong effect on char reactivity for certain coals. Overall, the increase of temperature provoked an enhanced plasticity and a more extensive consolidation during the metaplast stage of pyrolysis and reduced the amount of unfused material in the chars. This effect was more pronounced in low volatile bituminous vitrinites and low rank inertinites. The presence of inertinite derived materials in high rank coal chars enhanced their reactivities, whereas the opposite was observed for low rank coal chars. This was attributed to the fact that inertinite macerals yield both isotropic and anisotropic materials: inertinite in low rank coals increases the amount of anisotropic, less reactive char, but reduces it in high rank coals.

This study reports on the reactivity of chars obtained at 1000°C and 1300°C (within the range of temperatures reached by coal particles in the near-burner zone of pulverised fuel boilers) from three different coals. The coals were selected according to petrographic criteria: two of them are high volatile bituminous coals differing in maceral composition and the third one is a vitrinite-rich low volatile bituminous coal. The morphology and optical texture of the chars were studied by optical microscopy. The kinetic parameters for the combustion of the high temperature chars under Regime I (combustion controlled by chemical kinetics) have been obtained and related to the optical texture and reflectance of the chars. The intrinsic reactivity of the high temperature chars was found to be lower than that of the low temperature chars, whereas the enhanced porosity observed in the high temperature chars had a positive effect on their combustion reactivity under Regime II (combustion controlled by oxygen pore diffusion). The intrinsic reactivities of the chars decreased following the sequence: vitrinite-rich low rank char>inertinite-rich char>vitrinite-rich high rank char. As the combustion temperature increases, the reactivity of the inertinite-rich char approaches that of the low rank vitrinite-rich char, which justifies the good performance observed for high volatile bituminous inertinite-rich coals in power plants.

Unidirectional carbon/carbon composites were prepared using polyacrylonitrile-based carbon fibres and a commercial coal-tar pitch. The preparation includes a three-sequential-step process: (i) prepreging, (ii) moulding/pressing, and (iii) carbonization to 1000 degrees C. The effect of the process parameters including pressure, mould characteristics, and temperature and duration of pressure application on the microstructure of composites was monitored by light microscopy. Results show that the application of a pressure of 1 MPa close to the temperature of pitch solidification produces lower porosity composites. This porosity is significantly reduced when the solidification of the pitch is tempered by the introduction of a soak time of 10 h at the temperature at which pressure is applied.

In this work, the global pyrolysis kinetics of a broad range of coals was studied by means of thermogravimetric experiments (heating rate = 25 °C/min). An Arrhenius-based deconvolution model was applied to the experimental DTG curves in order to obtain reliable kinetic parameters for the different DTG peaks. The model assumes that the weight loss rate ascribed to volatile release during primary and secondary pyrolysis is a result of the parallel occurrence of three pseudo-unimolecular nth-order reactions (peaks 1, 2, and 3). The kinetic results were expressed as a function of coal rank (0.43 ≤ R r ≤ 1.14%) and maceral composition in order to obtain reliable kinetic trends. By error minimization, an average apparent reaction order of 1.67 was found. The mass fractions corresponding to peaks 1, 2, and 3 were found to follow definite trends with rank and maceral composition. The temperature of maximum reactivity for peak 1 was almost coincident with that of the maximum overall reactivity and followed clear trends with coal rank and type. The activation energies of peaks 2 and 3 were found to be independent of coal type and clearly related to coal rank. The kinetic parameters (activation energy and preexponential factor) of the three peaks exhibited clear isokinetic effects. It is thought that the deviations of the obtained activation energies from those calculated by the isokinetic effect trends are a consequence of a narrow distribution of activation energies within each peak.

The aim of this work is to study the changes in the chemical composition of a commercial impregnating coal-tar pitch due to the thermal treatment, using whole samples and the corresponding single isotropic phases and mesophases separated by hot filtration. A deeper knowledge of the molecular size and structure of the components present in the samples was achieved by means of size exclusion chromatography (SEC), planar chromatrography (PC), UV-fluorescence (UV-F), solid and solution-state 13C NMR and MALDI-mass spectrometry. The results showed that during thermal treatment there is not only a change in the relative amounts of different molecular size compounds but also in the characteristics of the compounds in each SEC fraction which increase in size with increasing treatment. The study of the single isotropic phases and mesophases yielded some interesting results, which were correlated with the different molecular structure of the compounds present in each phase.

Selective oxidation with RuO4 is used to detect differences in the molecular structure of two high-softening-point pitches obtained by the thermal treatment and air-blowing of a commercial impregnating pitch. The results of the characterization of the parent pitches and RuO4 oxidation products by chromatographic techniques have revealed differences in the condensation degree of the pitches. These differences are confirmed by the amount of CO2 evolved during the reaction, which also yields information about their reactivities.

Components of polymerized pitches are of large molecular size and consequently difficult to characterize. Moreover, pitches with similar degrees of polymerization obtained by different treatments have similar properties but different molecular structures. Selective oxidation with RuO4 has proven to be a suitable method for the elucidation of structural details in other complex carbonaceous substances such as coals, asphaltenes, or kerogens. In this paper the behavior of some model compounds was studied in order to achieve a better understanding of how this specific oxidation affects several possible pitch structures. To improve the efficiency of the reaction, an ultrasonic bath was used. Highly condensed compounds such as coronene and triphenylene were the most reactive, as they were the most oxidized of all the compounds tested. On the other hand, it was found that aryl−aryl bonds are very stable. The ability of RuO4 to distinguish between different molecular structures could be used as a new tool in the...

A commercial impregnating coal-tar pitch was thermally treated at 430°C for times varying between 2 and 6 h and the same pitch was air-blown at 275°C for between 10 and 30 h. Both series of pitches were characterized and their properties compared. The pitches from the thermal treatments contained mesophase, the amount increasing from 10 vol.% to 65 vol.% with increasing time of treatment, whereas those from the air-blowing were completely isotropic. The study of the pitches revealed that the thermally treated pitches still contained a considerable amount of light compounds together with the large planar molecules generated. On the contrary, light components polymerized to a considerable extent during air-blowing to form cross-linked molecules. Evidence of cross-linked structures is provided by a decrease in the iodine uptake and also by the X-ray diffraction results. Furthermore, extensive removal of aliphatic hydrogen took place during pitch air-blowing, as confirmed by the increase in the aromaticity indices of the pitches.

Four pitches (a commercial impregnating coal-tar pitch, an air-blown pitch and two thermally treated coal-tar pitches) and four granular carbons (graphite, anthracite, petroleum coke and foundry coke) were used to prepare carbon composites. A preliminary study of the main parameters involved in the preparation process of the carbon composites was carried out for the selection of the most suitable conditions. Mixtures with 30 wt.% of pitch and a moulding pressure of 80 MPa were selected and used for the preparation of all carbon composites. The behaviour of the resultant materials during carbonisation influenced their final properties. Composites obtained from the commercial pitch and air-blown pitch combined with anthracite and foundry coke deformed on carbonisation, presenting a high porosity and low mechanical properties. Materials obtained from the thermally treated pitches, foundry coke and anthracite were the ones with the highest compressive strength. The frictional behaviour of the materials was mainly governed by the type of granular carbon used.

Five unidirectional C–C composites were prepared using PAN-based carbon fibres and five pitches differing only in their inherent solid particles (QI) content. The results show that QI content affects the microstructure of the composite matrices The amount of smaller size crystalline structures (mosaic-like) increases with the increase of pitch QI content. On the other hand, QI particles also produce a significant increase in carbon yield, and consequently, composites show a higher percentage of carbon matrix. Mechanical properties, especially compressive strength, are also affected by the presence of QI particles. With the increase in QI content the mechanical properties of the composites are improved. However, this improvement always brings about a more brittle behaviour in the material, which is mainly due to the increase in the strength of fibre–matrix bonding. A good correlation between compressive and apparent interlaminar shear strength was found.

The proximate and ultimate analyses of coals are commonly regarded as sufficient for a satisfactory description of their chemical composition. This is no doubt true if coal is considered as a whole, but it has to be borne in mind that coals are actually composed of fairly different materials (macerals), and that the corresponding chemical characterization data are average values of the individual compositions of the macerals present in the coal. As regards the determination of coal maturity, the volatile matter content is widely used as a rank parameter, although this characteristic varies not only with coalification but also with maceral composition. A full description of the chemistry of coals, for the prediction of their behavior during industrial processing, requires that the characteristics of their maceral components is also known. This paper is an attempt to evaluate the relative contributions of vitrinite, liptinite, and inertinite to the volatile matter content of coals, over the entire coalifica...

This study is concerned with the conversion of anthracene oil into products with potential applications as precursors of graphitizable carbons. Air-blowing of anthracene oil induces polymerization/condensation reactions between its components. The extent of these reactions depends on temperature (250–325°C), time (5–15 h), air-flow (60–120 l h −1 kg −1 ) and reactor load. Anthracene oil conversion was monitored from the residue obtained by thermogravimetric analysis at 350°C, toluene insolubles and the carbon yield of resultant products. Differences in composition and pyrolysis behavior were established by elemental analysis, Fourier transformed infrared spectra and thermogravimetric analysis. Variations in the reactivity of the main components of the anthracene oil were studied by gas chromatography. The influence of the experimental conditions on the graphitizability of the carbons obtained from the reaction products was also assessed. All the variables have a significant influence on the composition and properties of the resultant products, so a great variety of products can be obtained by modifying or combining the process variables. The results suggest that air-blowing could be a suitable process for the conversion of anthracene oil into carbon precursors with potential industrial applications.

The isotropic and anisotropic phases which co-exist in thermally treated coal-tar pitches (10–65 vol.% mesophase) were separated by pitch filtration. Optical microscopy showed that the filtrates were 100% isotropic, while the filtration residues had mesophase contents between 75 and 87 vol.%. The values of the characteristic parameters of the thermally treated pitches calculated from those of the fractions were in close agreement with the experimental values, indicating that the phases did not alter during the separation process. Comparison of the properties of the fractions showed that the anisotropic phases had a higher degree of polymerization than the isotropic phases, as reflected by the higher C/H atomic ratio, toluene and N-methyl-2-pyrrolidone insoluble content and carbon yield. Moreover, the effects of thermal treatment on the evolution of each phase were also studied. An increase in the degree of polymerization was observed in both phases.

This study reports the chemical and petrographic characteristics of chars obtained at 1000 and 1300°C (within the range of temperatures reached by coal particles in the near burner zone of pulverised fuel boilers) from three different coals. The coals were selected according to petrographic criteria: two of them are low and high volatile bituminous vitrinite-rich coals, and the third one has similar rank to the high volatile bituminous coal but a very different maceral composition (97% inertinite). The residual volatiles remaining after pyrolysis at the two temperature tested were determined by heating the chars in a thermobalance at 1100°C under nitrogen. Also, the morphology and optical texture of the chars were studied by optical and scanning electron microscopy. The increase in preparation temperature enhanced the plastic behaviour of the low volatile bituminous coal, resulting in an extensive development of secondary porosity. The drop in reactivity from low to high temperature char might be due to the enhanced fluidity of the metaplast, which increases the likelihood for polymerisation reactions to take place, with a parallel reduction in the number of active sites. Incomplete devolatilisation and poor plastic properties were achieved during low temperature pyrolysis of the inertinite-rich coal, whereas at 1300°C most of the material passed through a fairly plastic stage and was very efficiently pyrolysed. No significant differences were observed between the low and the high temperature chars from the high bituminous vitrinite-rich coal. This behaviour could be due to either extensive crosslinking reactions involving hydroxylic oxygen in an early stage of the pyrolysis process, or, which seems more likely, to the sheltering effect of soot particles formed in the vicinity of pyrolysing coal particles, which could minimise the effect of the increased flame temperature.

Successional patterns of beetles inhabiting dung pats were examined during May and July 1993 in a mountain area in northern Spain (Picos de Europa). Beetles belonging to six families were caught during the course of succession (30 d). Coprophagous beetles were more abundant in dung pats than predatory beetles (89 and 11 %, respectively). A trophic sequence was observed in relation to age of the dung, coprophagous beetles occurring earlier in the dung than predatory beetles. The pattern was observed on two occasions during the season, though succession proceeded somewhat faster in July than in May. These results suggest that food availability and microclimatic conditions in dung pats appear to determine the successional occurrence of beetle taxa. On the other hand, coprophagous species (Aphodius) were poorly segregated along the successional axis. Null models failed to support the hypothesis that successional overlap and differences in successional mean occurrence between species could be the result of competition. Successional patterns at the specific level probably reflect differences in behaviour, such as pat location, feeding, mating, egg-laying and larva requirements, rather than competitive replacement.

The aim of this paper is to study the applications of chromatography and related techniques in the transformation of coal-derived products into pitches for specific uses. Anthracene oil, tar and pitch were thermally treated in the presence of air (and sulfur in the case of anthracene oil) in order to cause the polymerization/condensation of their components. The evolution of the components of the parent materials during the treatments was monitored by gas chromatography-mass spectrometry, gas chromatography-atomic emission detection, probe mass spectrometry and size-exclusion chromatography. From the results obtained, possible mechanisms for the transformation of coal-derived products into new pitches were established.

This study is concerned with the preparation of high carbon yield coal-tar pitches by tar air-blowing under pressure (0.5 MPa). The influence of the temperature (275–325°C), reaction time (0–20 h) and air flow (60–120 l h−1) on pitch composition and properties were monitored by elemental analysis, solubility measurements and Fourier transform infrared spectroscopy. Pyrolysis behaviour of parent tar and resultant pitches was studied by thermogravimetric analysis thermogravimetric/derivative-thermogravimetric (TG/DTG) curve and polarized-light microscopy. The development of mesophase was monitored in the resultant pitches by optical microscopy of their pyrolysis products obtained at 450°C. Results show that air-blowing of tar, performed under mild conditions, promotes the condensation of molecular components producing cross-linked oligomers, so increasing the yield of the process. The extent of polymerization increased with severity of treatment and resulted in an increase of pitch carbon yield. Moreover, the different properties of prepared pitches offer the possibility to obtain cokes with a wide range of optical textures.

A commercial impregnating coal-tar pitch was thermally treated at 430°C for 2–5 h in nitrogen. Resultant pitches, which contained mesophase ranging from 10 to 46 vol.%, were filtered to separate the isotropic phases, in order to study their contribution to the rheology of the whole pitches. The parent pitch, thermally treated pitches and the individual isotropic phases were characterized by measuring their elemental composition, softening point, carbon yield, solubility in toluene and in N-methyl-2-pyrrolidone, mesophase content (by optical microscopy) and X-ray diffraction parameters. The rheological behavior of the pitches and the isotropic phases was studied using steady shear rheometry. Results showed that not only had the whole pitches, which were partially anisotropic, a non-Newtonian behavior, but also the single isotropic phases.

A commercial anthracene oil was polymerized with anhydrous aluminium trichloride in the temperature range of 250–325°C. The kinetics of the process and the conversion of anthracene oil were monitored by thermogravimetric analysis, solubility parameters and carbon yield. The reactivity of the major anthracene oil components was monitored by gas chromatography. The cokes obtained at 900°C from reaction products were characterized in terms of optical texture and air reactivity. The results showed that the treatment of anthracene oil with aluminium trichloride led to pitch-like materials, temperature and aluminium trichloride concentration being the controlling parameters of anthracene oil conversion. The residue obtained by thermogravimetric analysis at 350°C was used as a measure of the degree of anthracene oil conversion. Cokes obtained by carbonization of reaction products, in which aluminium trichloride had previously been removed, showed an optical texture of a larger size and a lower air reactivity than cokes from reaction products where aluminium trichloride was present.

An anthracene oil with a boiling point of 250−370 °C was reacted with sulfur (5−20 wt %) at 250−300 °C for 2 h. The extent of anthracene oil conversion to a carbon precursor (pitch-like material) was monitored from the weights of the residues obtained by thermogravimetric analysis at 350 °C (R350), the temperature at which the anthracene oil residue is zero. Anthracene oil readily reacts with sulfur, the initial concentration of sulfur being the main controlling parameter of the reaction. The anthracene oil components showed different reactivities with sulfur, as determined by gas chromatography of the toluene-soluble fraction, and also followed different mechanisms because of their different structures. Studies by probe mass spectrometry of the pure compounds revealed the type of reaction mechanisms involved in the process. The amount of sulfur incorporated into the reaction products determined the optical texture of the resultant cokes.

This study is an attempt to find useful relationships between the petrographic characteristics of coals and their efficiencies during pulverized fuel combustion through the study of their pyrolysis chars. Specifically, the effects of coal rank have been investigated using a series of vitrinite-rich coals ranging from subbituminous to low volatile bituminous coal. The behavior of these coals during combustion at 500 and 1100 °C and the petrographic characteristics of their pyrolysis chars (1000 °C) were investigated. In a foregoing paper (Borrego et al.10), unexpectedly poor combustion performances were found for some hvBb coals, which were attributed to rank rather than maceral effect. A general pattern of variation of coal burnout with rank was found in this study, providing additional data in which those unexpected results could be fitted. The observed trend was explained in terms of the changes undergone by coal both during coalification and pyrolysis, which make the number and accessibility of active ...

Quick studies on biodiversity are frequently used in conservation assessments. Conclusions from these studies would be consistent if assemblages under consideration are stable over time. The stability of butterfly assemblages in the Picos de Europa in northern Spain was examined at several levels of numerical resolution. The survey was carried out in 1993 and 1995, which allowed at least one complete turnover of all individuals in each locality. Butterfly assemblages were usually stable at the levels of number of species and total number of individuals, species presence and absence, and abundance rankings. But, absolute abundances of individual species changed from 1993 to 1995 out of synchrony with one another. Regional distributions and altitudinal ranges of species were also stable. Assemblages were similar in both study years, judging by similar site ordinations by reciprocal averaging. Overall, these results are in accordance with most studies where stability has been examined at several numerical levels; they also suggest that abundances of individual species do not vary enough to disrupt overall assemblage abundance rankings. Butterfly assemblages at sites at higher altitude tended to be more unstable in terms of abundance rankings and absolute abundances. This agrees with ecological theory predicting less stable assemblages in physically ‘harsh’ environments. We concluded that monitoring for a relatively short time period can give a clear picture of both local and regional butterfly biodiversity and species composition.

Four unidirectional pitch-based C/C composites were densified by multiple melted pitch impregnation under vacuum followed by recarbonization to 1273 K. The pitches used for the impregnation were the same pitches used as carbon matrix precursors in the preparation of the C/C composites. Recarbonization steps in one of the composites were also performed under pressure in order to study the effect of pressure during the densification process. The efficiency of the impregnation was evaluated in terms of the voids accessible to the impregnant and was followed by the weight gain during the process and polarized-light microscopy of impregnated composites. Wide differences in the densification process were observed dependent primarily on the physical and chemical properties of the pitch, especially the carbon yield and pitch fluidity. The composites at different stages of densification were characterized by standard procedures (bulk density and porosity), and microscopical techniques (polarized-light microscopy, image analysis and scanning electron microscopy). On the basis of results a mechanism describing the whole process involved in the densification of unidirectional C/C composites is proposed.

A commercial impregnating coal-tar pitch was air-blown at 275 °C for 10, 18, 25 and 30 hours. Isotropie pitches were produced with softening points ranging from 140 to 210 °C. The parent and treated pitches were characterized by elemental analysis, Fourier transform infrared, solubility in toluene and N-methylpyrrolidone, iodine adsorption and reflected light optical microscopy. The viscoelasticity of the pitches also was investigated using transient shear and controlled strain oscillatory rheometry. The chemical characterization of the pitches suggested that, as air-blowing proceeded, larger molecules formed through dehydrogenative polymerization (aromatization/condensation) and cross-linking of the pitch molecules. This is consistent with the rheological characterization of the pitches. The results obtained from transient shear and oscillatory rheometry showed that the parent impregnating pitch exhibited a viscous behavior (typical of fluids composed of small molecules). In contrast, the air-blown pitches, which contained large aromatic molecules, showed viscoelastic properties.

The stacking modes of graphene oxide monolayers (GO) when forming thin films is a crucial aspect determining many properties especially those related with transport. Stacking, morphology and effects of thermal and chemical reduction are studied combining insitu synchrotron radiation diffraction and atomic force microscopy with simulations. The GO flakes mimic the substrate morphology and present an almost perfect stacking for few-layer films (2-10 layers) when in-plane flake size is large enough. The interlayer distance is found to be 1 nmirrespective of the film thickness and drastic discontinuities upon thermal annealing are observed between 100 and 200 -C. Moreover, the short GO-GO distance (0.38 nm) observed at temperatures (500 -C) where oxygen content is still high indicates that stacking is mainly governed by embedded water molecules. The large interlayer distance (0.76 nm) in chemically reduced films and its robustness against thermal annealing are due to the folding of the edges of the flakes occurring upon the elimination of the functional groups. The central part of the flakes remains extremely flat contrary to what occurs with thermal reduction. These structural defects induced by chemical and thermal reduction processes are very probably the most important limitations for electrical conductivity in GO based electrodes., X.D. acknowledges a FPI scholarship from Spanish MINECO and C.M. thanks financial support from the “Juan de la Cierva” postdoctoral program JCI-2011-08815. The research leading to these results has received funding from Spanish MINECO under projects MAT2012-37276-C03-01, MAT2011-27470-C02-02, CSD2009-00050 and CSD2009-00013 as well as from the European Union Seventh Framework Program under grant agreement n° 604391 “Graphene Flagship.”

Two coal tar pitches and a petroleum pitch were fractionated by extrography on a preparative scale. The chemical composition of the fractions was determined by elemental analysis, FT-i.r., 1H n.m.r. and solid-state 13C n.m.r. spectroscopies and number-average molecular weight, Mn, and their thermal behaviour was studied using thermal analysis techniques (t.g., d.t.g. and d.t.a.). The fractions were also carbonized in a horizontal furnace, and the resulting cokes were characterized by optical microscopy. Exo- and endothermic effects shown by the d.t.a. curves of extrographic fractions of the pitches were associated with the physicochemical phenomena expected to occur during the pyrolysis of their respective constituents. It was found that the composition of a pitch and the reactivity of its constituents are reflected in the degree of overlap between the endothermic effect of volatilization and the exothermicity of polymerization. The study of the optical texture of the cokes in relation to the chemical and structural composition of the pyrolysed samples provided new evidence on the relations between composition, reactivity and thermal behaviour of pitches.

The optical texture of cokes obtained at 500 °C (60 minutes soak time) from a range of pitches, coal-tar and petroleum pitches and from the extrography fractions of three of the pitches, was related to the chemical composition of the parent material. Small differences observed in the amount of polyaromatic hydrocarbons and basic nitrogen polyaromatic compounds present in vacuum-distilled and thermally treated binder pitches do not have a significant influence on the optical textures of the resultant cokes. However, when pitches of very different origins (binder pitches, impregnating pitches, petroleum pitches and low-temperature tar pitches) are compared, different distributions of classes of compounds in terms of molecular size and functional groups (as determined by extrography) have a definite effect on the optical texture of the coke, a wide range of structures being observed. The carbonization of pitch fractions obtained by extrography gave valuable information on the effect of specific types of compounds on the optical texture of cokes. Fractions rich in basic PANCs provided cokes with the best developed optical texture, whereas fractions constituted by PAHs were not completely converted into mesophase under the same pyrolysis conditions. It was also observed that pitch material not eluted during the extrographic fractionation, which is highly polar, adversely affects the development of the optical texture of the cokes.

In this chapter we compile a battery of biophysical and imaging methods suitable to investigate adenovirus structural stability, structure, and assembly. Some are standard methods with a long history of use in virology, such as embedding and sectioning of infected cells, negative staining, or immunoelectron microscopy, as well as extrinsic fluorescence. The newer cryo-electron microscopy technique, which combined with advanced image processing tools has recently yielded an atomic resolution picture of the complete virion, is also described. Finally, we detail the procedure for imaging and interacting with single adenovirus virions using the atomic force microscope in liquid conditions. We provide examples of the kind of data obtained with each technique.

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In this chapter we compile a battery of biophysical and imaging methods suitable to investigate adenovirus structural stability, structure, and assembly. Some are standard methods with a long history of use in virology, such as embedding and sectioning of infected cells, negative staining, or immunoelectron microscopy, as well as extrinsic fluorescence. The newer cryo-electron microscopy technique, which combined with advanced image processing tools has recently yielded an atomic resolution picture of the complete virion, is also described. Finally, we detail the procedure for imaging and interacting with single adenovirus virions using the atomic force microscope in liquid conditions. We provide examples of the kind of data obtained with each technique.

Adenovirus fibre proteins play an important role in determining viral tropism. The C-terminal domain of the fibre protein from snake adenovirus type 1, a member of the Atadenovirus genus, has been expressed, purified and crystallized. Crystals were obtained belonging to space groups P2(1)2(1)2(1) (two different forms), I2(1)3 and F23. The best of these diffracted synchrotron radiation to a resolution of 1.4 Å. As the protein lacks methionines or cysteines, site-directed mutagenesis was performed to change two leucine residues to methionines. Crystals of selenomethionine-derivatized crystals of the I2(1)3 form were also obtained and a multi-wavelength anomalous dispersion data set was collected.

The standard pathway for virus infection of eukaryotic cells requires disassembly of the viral shell to facilitate release of the viral genome into the host cell. Here we use mechanical fatigue, well below rupture strength, to induce stepwise disruption of individual human adenovirus particles under physiological conditions, and simultaneously monitor disassembly in real time. Our data show the sequence of dismantling events in individual mature (infectious) and immature (noninfectious) virions, starting with consecutive release of vertex structures followed by capsid cracking and core exposure. Further, our experiments demonstrate that vertex resilience depends inextricably on maturation, and establish the relevance of penton vacancies as seeding loci for virus shell disruption. The mechanical fatigue disruption route recapitulates the adenovirus disassembly pathway in vivo, as well as the stability differences between mature and immature virions, We acknowledge funding by grants from the Ministry of Science and Innovation of Spain, PIB2010US-00233, FIS2011-29493, Consolider CSD2010-00024 and CAM project and the Comunidad de Madrid No. S2009/MAT-1467 to P. J. P.; BFU2010-16382/BMC to C.S.M.; and FIS2011-16090-E to C.S.M. and P.J.P. S.J.F acknowledges funding from the National Institutes of Health, USA (GM037705 and AI1058172). A.J.P.-B. holds a Juan de la Cierva postdoctoral contract from the Ministry of Science and Innovation of Spain; A.O.-E. and R.M.-C. are recipients of predoctoral fellowships from the Ministry of Education and the Instituto de Salud Carlos III of Spain, respectively

This study was undertaken to gain further insight into the types of interaction between pitch and carbon black (CB) occurring during thermal treatment in the initial stages of carbonization, and the effects on subsequent coke structure. A commercial coal-tar pitch was blended with CB and then thermally treated at temperatures between 400–450 °C, for 5 hours—except for 430 °C, where the time of treatment was for 10 hours. The same thermal treatments were applied in the absence of CB to test the effects of temperature alone. Parent and treated pitches were characterized by elemental analysis, optical microscopy, thermomechanical analysis (TMA) and sequential solvent extraction. Additionally, some of the fractions were characterized by FTIR, GC and 1 H-NMR. Cokes obtained at 900 °C were characterized by optical microscopy in terms of their porosity and optical texture. Results show that the type of CB/pitch interactions are temperature dependent, these interactions being more significant at lower temperatures (below 425 °C). Hydrogenation and polymerization reactions have successively occurred along the range of temperatures used. CB produced an increase of pitch carbon yield without affecting pitch fluidity at the lower temperatures. The effect on the reduction of coke porosity was pronounced at the initial stages of the treatment. Coke optical texture was also affected by the presence of CB showing smaller sizes.

The effects or vegetation cover on the abundance and species richness of dung beetles (Aphodiidae) were examined in three altitudinal zones: lowland (520–600 m), mid-altitude (950–963 m) and highland (1230–1275 m). Pitfall traps baited with fresh cattle dung were placed in three vegetation types at each altitudinal zone: forest, heathland and pasture. Species richness was lower in forests than in the other vegetation types. The total abundance of beetles also varied with vegetation type, but the effect was dependent on altitude. Number of individuals was higher in pasture at highlands and in heathland and forest at mid-altitude and lowlands. An altitudinal dependence of distribution of individuals between vegetation types was also found for the more abundant species in the study area. These results could be explained if the local distribution of individuals between vegetation types was determined by microcli-matic factors, mainly temperature. Differences in altitude between sites are associated with temperature changes, determining the habitat selection of species at each altitude.

Graphene oxide (GO) forms persistent dispersions in aqueous solutions up to concentrations of 0.2 mg mL(-1). Addition of methylene blue (MB) to these aqueous dispersion of GO gives rise to the observation in optical spectroscopy of new absorption bands that are indicative of the formation of MB/GO conjugates. Four new absorption maxima have been characterized, and their intensity varies depending on the relative concentration of MB with respect to GO. Two of these bands appearing at 677 and 757 nm correspond to individual MB molecules adsorbed on neutral or acid sites of GO, respectively. Two other bands at 615 and 580 nm are attributable to adsorbed MB molecules showing interaction with other neighbor dye molecules at incomplete (615 nm) or complete (580 nm) surface coverage. Complete coverage of GO surface by MB causes the formation of a precipitate and the separation of the MB/GO conjugate. EDS mapping of carbon and sulfur atoms of MB/GO conjugate indicates the homogeneous distribution of MB molecules coating GO sheets. A simple and reliable protocol for surface area measurement and determination of the level of aggregation for GO dispersions in water has been proposed by determining the amount of MB that leads to the maximum intensity of the 580 nm band and precipitation of the MB/GO conjugate. Specific surface area as high as 736.6 m(2) g(-1) in the range of the theoretical value for GO has been experimentally measured for diluted GO solutions, but aggregation levels of 15% were estimated for GO concentration of 50 mu g mL(-1)., Financial support by the Spanish Ministry of Economy and Competitiviness (Sever Ochoa, Generalitat Valenciana (Prometeo 20112/013) and CTQ2012-32315) is gratefully acknowledged. P. Montes-Navajas also thanks the Universidad Politecnica de Valencia for a postdoctoral contract for excellence (CEI-01-11, 20090796). The authors also thank the Spanish Science and Innovation Ministry (CONSOLIDER INGENIO 2010, ref. CSD2009-00050) for their financial support.

Two pitches of different volatile contents, obtained from the same coal tar by different procedures, were characterized by elemental analysis, solubility, 1H n.m.r., donor—acceptor ability, FT-i.r., extrography and size-exclusion chromatography. Their pyrolysis behaviour was followed by hot-stage microscopy and thermogravimetric analysis. The pitches were carbonized in a horizontal furnace and the resulting cokes were characterized by optical microscopy. Three partly devolatilized pitches were prepared by thermal treatment of the two pitches and their pyrolysis behaviour was compared in terms of mesophase development and optical texture of coke. The results indicate a significant influence of low-molecular-weight components of pitch on the development of mesophase but no effect on the subsequent optical texture of the coke.