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Unlike fuels, different grades of bitumen meeting physico-chemical and performance requirements can be made economically only from specific types of crude oils. Crude selection for this purpose is therefore very important. Methods used (both empirical and laboratory) for determining the bitumen potential of the crude are described with their limitations. The laboratory method is considered more complete and gives fuller and more precise information regarding yield and quality. Contrairement aux combustibles, les différentes catégories de bitumes, aux caractéristiques physico-chimiques et aux performances convenables, ne peuvent être obtenues économiquement qu'à partir de pétroles bruts bien spécifiques. Le choix des pétroles bruts adaptés à la fabrication des bitumes est donc très important. On décrit dans cet article les méthodes empiriques et de laboratoire utilisées pour déterminer le potentiel en bitume des pétroles bruts, en précisant leurs limites. On considère que la méthode de laboratoire est plus complète et qu'elle donne des informations plus nombreuses et précises sur le rendement et la qualité.

Effect of process variables viz. air rate, time of air blowing, temperature and catalyst concentration has been investigated and optimised to determine the possibility of making paving grade bitumen from 500°C+ Aghajari Short residue, of appropriate temperature susceptibility. Structural parameters of feed and some typical air blown products determined through NMR spectroscopy to follow the reaction mechanism leading to formation of increased asphaltene content during air blowing are also described. On a étudié et optimisé l'effet des variables du procédé comme le débit de l'air, le temps de soufflage, la température et la concentration en catalyseurs afin de déterminer la possibilité de fabriquer du bitume routier d'une susceptibilité à la température convenable, à partir d'un résidu Aghajari 500 °C+ de distillation poussée. On présente également les paramètres structuraux de la charge et de quelques produits types du soufflage, déterminés par résonance magnétique nucléaire, pour suivre le mécanisme de la réaction conduisant à une augmentation de la teneur en asphaltènes durant le soufflage d'air.

Production of quality bitumen from less suitable/non bitumen bearing crudes continues to be a challenging task for the refineries. Blending of short residues prior to processing is helpful to a limited extent. Generation of asphaltics low in wax through appropriate processing and their conversion to quality bitumen in admixture with suitable fluxes appears more practical approach. It is described with the help of experimental results. La production de bitume de qualité à partir de bruts contenant peu ou pas du tout de bitume naturel demeure une tâche difficile pour les raffineurs. Le problème est dû au déséquilibre de certains constituants des hydrocarbures, à savoir : les asphaltènes et les malthènes, composés de résines, de fractions aromatiques, de fractions naphténiques et de paraffine. Le traitement de ces matières premières ne permet pas d'obtenir des bitumes possédant des propriétés rhéologiques et physiques acceptables à haute et basse température. En fait, ces produits de base ont tantôt une teneur insuffisante en asphaltènes, tantôt une teneur excessive en paraffine, et parfois même les deux défauts. De plus, les matières premières à base paraffinique ont une forte densité API et une faible teneur en soufre. Le traitement des résidus de ces bruts doit donc être effectué par un procédé capable d'améliorer leurs propriétés et d'obtenir un bitume possédant les mêmes qualités que ceux que l'on tire des bruts bitumineux, comme ceux du Moyen Orient. La méthode préconisée par Ditman est peut-être la première tentative pour extraire des bitumes à partir des bruts à base paraffinique provenant d'Afrique du Nord. Les données ci-dessus et les expériences effectuées par les auteurs permettent de proposer les deux voies suivantes pour la production de bitumes de qualité à partir de résidus de bruts impropres : a) Désalphatage des résidus courts. b) Distillation des résidus courts sous pression très réduite (distillation poussée). Les produits asphaltiques obtenus par le premier procédé ont une faible teneur en paraffine mais ils sont durs (faible pénétration) et cassants. Il peuvent être transformés en bitumes de qualité par mélange avec des agents de fluxage appropriés. La distillation sous pression très réduite élimine à moindre coût l'huile et la paraffine des résidus courts, sous une température aussi basse que possible ; il ne reste que des résidus à teneur faible en paraffine, un peu plus forte en asphaltènes, et à faible pénétration. Tout comme les asphaltènes PDA (analyse différentielle de pression) provenant de distillats de craquage, ces résidus sont ensuite mélangés et traités avec des agents de fluxage appropriés pour donner des bitumes de qualité. Ces deux procédés sont envisages pour la transformation des résidus courts issus du traitement des bruts d'Assam en bitumes de qualité. On trouvera ci-après le résumé des données correspondant au procédé d'obtention des asphaltènes à partir de distillats de craquage (PDA). L'article décrit les deux méthodes ci-dessus et les résultats obtenus, en particulier pour ce qui concerne les spécifications courantes du bitume.

A field experiment was conducted to standardize the source of transplanting material and method for off-season (kharif season) menthol-mint (Mentha arvensis L.) cultivation. For this purpose, stem and stolons were evaluated as transplanting materials and their responses were ascertained with respect of yield, yield attributes, and essential oil quality using conventional and furrow-irrigated raised bed (FIRB) methods. The results revealed that different transplanting materials, stem and stolons, were similar in biomass yield, yield attributes, and nutrient uptake. Transplanting of menthol-mint on FIRB (1.2-m wide) provided significantly higher yield, yield attributes, and nutrient uptake as compared to other methods of transplanting. Stem-transplanted menthol-mint crop provided significantly higher plant height (81.9cm), number of branchesplant-1 (87), biomass yield (18.67Mgha-1), oil yield (205.4Lha-1), menthol content (76.5%), and nutrient uptake under FIRB (1.2-m wide) as compared with the other treatments. [ABSTRACT FROM AUTHOR]

Experiments were carried out at Lucknow (India) to standardize protocols for derivation of cuttings from rose-scented geranium (Pelargonium graveolens) plants and converting them into rooted propagules. The protocol could give more than 1,500 cuttings/plant in ∼16 weeks. The cuttings planted in polybags or in field plots over soil + FYM or NPK developed into rooted propagules suitable for field cropping in 6 weeks. The field-produced propagules were suitable for planting in areas near their production, and the propagules produced in polybags were suitable for planting both locally and for transporting to distant locations geranium planting. [ABSTRACT FROM AUTHOR]

The essential oil composition of fresh aerial parts of Bothriochloa bladhii (Retz.) S.T. Blake was analyzed by capillary GC-FID and GC-MS methods. The analysis led to the identification of 60 constituents forming 89.6% of the total oil compositions dominated by monoterpenoids (46.0%) and sesquiterpenoids (35.6%). The major constituents identified were acorenone-B (20.9%), camphene (20.8%), isobornyl acetate (7.4%), acorenone (3.8%), limonene (3.6%) and a-pinene (3.5%). Other constituents identified were borneol (2.8%), neointermedeol (2.1%), tricyclene (2.3%) and intermedeol (1.6%). Comparison of the results with previous reports showed considerable qualitative and quantitative variations in essential oil constituents. [ABSTRACT FROM AUTHOR]

Modelling of skin sensitization data of 255 diverse compounds and 450 calculated descriptors was performed to develop global predictive classification models that are applicable to whole chemical space. With this aim, we employed two automated procedures, (a) D-optimal design to select optimal members of the training and test sets and (b) k-Nearest Neighbour classification (kNN) method along with Genetic Algorithms (GA-kNN Classification) to select significant and independent descriptors in order to build the models. This methodology helped us to derive multiple models, M1-M5, that are stable and robust. The best among them, model M1 (CCRtrain = 84.3%, CCRtest = 87.2% and CCRext = 80.4%), is based on six neighbours and nine descriptors and further suggests that: (a) it is stable and robust and performs better than the reported models in literature, and (b) the combination of D-optimal design and GA-kNN classification approach is a very promising approach. Consensus prediction based on the models M1-M5 improved the CCR of training, test and external validation datasets by 3.8%, 4.45% and 3.85%, respectively, over M1. From the analysis of the physical meaning of the selected descriptors, it is inferred that the skin sensitization potential of small organic compounds can be accurately predicted using calculated descriptors that code for the following fundamental properties: (i) lipophilicity, (ii) atomic polarizability, (iii) shape, (iii) electrostatic interactions, and (iv) chemical reactivity. [ABSTRACT FROM AUTHOR]

Abstract: Since it was first detected in 1996, the Goose/Guangdong/1/1996 (Gs/GD) H5N1 influenza virus and its reassortants have spread to over 60 countries, with over 20 distinct genetic reassortants previously recognized. However, systematic analysis of their interrelationship and the development of genetic diversity have not been explored. As each of those reassortants was first detected in China, here 318 full-length H5N1 virus genomes isolated from 1996 to 2006 in this region were phylogenetically analyzed. Our findings revealed two major group reassortment events in 2001 and 2002 that were responsible for the generation of the majority of the 44 distinct Gs/GD genotypes identified, excepting those 1997 variants. Genotype replacement and emergence occurred continually, with 34 transient genotypes detected while only 10 variants were persistent. Two major replacements of predominant genotypes were also observed: genotype B replaced by Z in 2002 and then genotype Z replaced by the now predominant genotype V in 2005. [Copyright &y& Elsevier]

Intrinsic cardiac adrenergic (ICA) cells in developing rat heart constitute a novel adrenergic signaling system involved in cardiac regulation. Regulatory mechanisms of ICA cells remain to be defined. Immunohistochemical study of fetal rat hearts demonstrated ICA cells with catecholamine biosynthetic enzyme tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT). The mRNA of TH and PNMP was also detected in fetal rat hearts before sympathetic innervation. Immunoreactivity of norepinephrine transporter (NET) was localized to ICA cells in rat heart tissue and primary cell culture. For the functional study, the activity of intracellular Ca2+ concentration ([Ca2+]i) transients was quantified by a ratio fluorescent spectrometer in cultured ICA cells and myocytes. ICA cells generated spontaneous [Ca2+]i transients that were eliminated by tetrodotoxin or Ca2+-free solutions and showed greatly reduced amplitude with the addition of L-type Ca2+ channel blocker nifedipine. [³H]norepinephrine studies demonstrate release and uptake of norepinephrine. Functional interaction between catecholamines produced by the ICA cells and cocultured myocytes was evident by the effect of the β-adrenergic blocker atenolol eliciting a dose-dependent reduction in the amplitude and frequency of [Ca2+]i transients of beating myocytes. Hypoxia inhibited [Ca2+]i transient activity of ICA cells, which subsequently produced a reoxygenation-mediated rebound augmentation of [Ca2+]i transients. We conclude that ICA cells are capable of catecholamine synthesis, release, and uptake. They generate spontaneous [Ca2+]i transient activity that can be regulated by oxygen tension. ICA cells may provide an alternative adrenergic supply to maintain cardiac contractile and pacemaker function at rest and during stress in the absence of sympathetic innervation. [ABSTRACT FROM AUTHOR]

H9N2 influenza viruses have become established in terrestrial poultry in different Asian countries over the last 2 decades. Our previous study demonstrated that quail harbor increasingly diverse novel H9N2 reassortants, including both Chicken/Beijing/1/94 (Ck/Bei-like) and Quail/Hong Kong/G1/97 (G1-like) viruses. However, since 1999, the genesis and evolution of H9N2 viruses in different types of poultry have not been investigated systematically. In the present study, H9N2 viruses isolated from chickens, ducks, and other minor poultry species were characterized genetically and antigenically. Our findings demonstrate that Ck/Bei-like H9N2 viruses have been introduced into many different types of poultry in southern China, including quail, partridges, chukar, pheasant, guinea fowl, and domestic ducks, while G1-like viruses were commonly detected in quail, less frequently detected in other minor poultry species, and not detected in chickens and ducks. Genetic analysis revealed 35 genotypes of H9N2 viruses, including 14 novel genotypes that have not been recognized before. Our results also suggested that two-way interspecies transmission exists between different types of poultry. Our study demonstrates that the long-term cocirculation of multiple virus lineages (e.g., H5N1 and H9N2 viruses) in different types of poultry has facilitated the frequent reassortment events that are mostly responsible for the current great genetic diversity in H9N2 and H5N1 influenza viruses in this region. This situation favors the emergence of influenza viruses with pandemic potential. [ABSTRACT FROM AUTHOR]

The transmission of highly pathogenic avian influenza H5N1 virus to Southeast Asian countries triggered the first major outbreak and transmission wave in late 2003, accelerating the pandemic threat to the world. Due to the lack of influenza surveillance prior to these outbreaks, the genetic diversity and the transmission pathways of H5N1 viruses from this period remain undefined. To determine the possible source of the wave 1 H5N1 viruses, we recently conducted further sequencing and analysis of samples collected in live-poultry markets from Guangdong, Hunan, and Yunnan in southern China from 2001 to 2004. Phylogenetic analysis of the hemagglutinin and neuraminidase genes of 73 H5N1 isolates from this period revealed a greater genetic diversity in southern China than previously reported. Moreover, results show that eight viruses isolated from Yunnan in 2002 and 2003 were most closely related to the clade 1 virus sublineage from Vietnam, Thailand, and Malaysia, while two viruses from Hunan in 2002 and 2003 were most closely related to viruses from Indonesia (clade 2.1). Further phylogenetic analyses of the six internal genes showed that all 10 of those viruses maintained similar phylogenetic relationships as the surface genes. The 10 progenitor viruses were genotype Z and shared high similarity (=99%) with their corresponding descendant viruses in most gene segments. These results suggest a direct transmission link for H5N1 viruses between Yunnan and Vietnam and also between Hunan and Indonesia during 2002 and 2003. Poultry trade may be responsible for virus introduction to Vietnam, while the transmission route from Hunan to Indonesia remains unclear. [ABSTRACT FROM AUTHOR]

An H6N1 virus, A/teal/Hong Kong/W312/97 (W312), was isolated during the "bird flu" incident in Hong Kong in 1997. Genetic analysis suggested that this virus might be the progenitor of the A/Hong Kong/156/97 (HK/97) H5N1 virus, as seven of eight gene segments of those viruses had a common source. Continuing surveillance in Hong Kong showed that a W312-like virus was prevalent in quail and pheasants in 1999; however, the further development of H6N1 viruses has not been investigated since 2001. Here we report influenza virus surveillance data collected in southern China from 2000 to 2005 that show that H6N1 viruses have become established and endemic in minor poultry species and replicate mainly in the respiratory tract. Phylogenetic analysis indicated that all H6N1 isolates had W312-like hemagglutinin and neuraminidase genes. However, reassortment of internal genes between different subtype virus lineages, including H5N1, H9N2, and other avian viruses, generated multiple novel H6N1 genotypes in different types of poultry. These novel H6N1/N2 viruses are double, triple, or even quadruple reassortants. Reassortment between a W312-like H6N1 virus and an A/quail/Hong Kong/G1/97 (HK/97)-like H9N2 virus simultaneously generated novel H6N2 subtype viruses that were persistent in poultry. Molecular analyses suggest that W312-like viruses may not be the precursors of HK/97 virus but reassortants from an HK/97-like virus and another unidentified H6 subtype virus. These results provide further evidence of the pivotal role of the live poultry market system of southern China in generating increased genetic diversity in influenza viruses in this region. [ABSTRACT FROM AUTHOR]