Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1572-879X
    Keywords: MoS2 ; WS2 ; thiosalts ; in situ activation ; hydrodesulfurization ; mechanochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The in situ decomposition of ammonium thiometallates during the hydrodesulfurization (HDS) of dibenzothiophene (DBT), to obtain molybdenum disulfide and tungsten disulfide catalysts, was investigated. It was found that very efficient catalysts for the HDS of DBT were obtained by in situ decomposition. Mechanical uniaxial pressing of the precursors (ammonium thiometallates) affected both textural and catalytic properties of the catalysts. Surface areas of molybdenum and tungsten disulfides increased as a function of uniaxial pressing, while catalytic activities went through a maximum. For MoS2, the hydrogenation selectivity was much higher for in situ catalysts than for ex situ ones. For WS2 catalysts, the hydrogenation selectivity was less sensitive to the condition of decomposition (ex situ/in situ). The surface S/M (M = Mo, W) atomic ratio from the Auger signal decreased as a function of uniaxial pressing, while the C/M ratio remained almost constant at 1.6. The best catalyst showed an experimental S/Mo ratio that is slightly higher than the stoichiometric value. The effect of in situ decomposition and mechanical deformation of thiometallate precursors is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-0878
    Keywords: Key words: Apoptosis ; Neuronal plasticity ; Hypothalamus ; Astrocytes ; Immunocytochemistry ; Western blot ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A polyclonal antibody raised against a peptide corresponding to the (2–19) amino-terminal sequence of the Bcl-xL/S protein was used to localize Bcl-x immunostaining in the central nervous system of rats at various postnatal ages. Whereas Bcl-x immunostaining was present in virtually all neurons of young animals (4 days postnatal), this staining became progressively restricted during the course of postnatal development. In adults, Bcl-x immunostaining was particularly strong in certain neurons present in a few hypothalamic nuclei, such as the supraoptic or the arcuate nuclei. Moderate staining was observed in some discrete brain regions, such as the olfactory bulb, the hippocampus, some catecholaminergic nuclei of the brainstem, and the cerebellum. Strong Bcl-x immunostaining was also exhibited in axon-like fibers located in the pyriform cortex, the median eminence, the dorsal medulla oblongata, and spinal cord. Bcl-x immunostaining was also present in astrocytes scattered throughout the white matter in the brain and the spinal cord, but was absent from those located in gray matter. Staining was particularly strongly expressed in reactive astrocytes densely packed along the borders of a central lesion or surrounding them, and in a large number of reactive astrocytes detected at a distance from the lesion. Our data suggest that, in addition to the possible stimulating effects on cell survival generally ascribed to Bcl-x, its maintained expression throughout adulthood or its re-expression following injury characterizes those neuronal or non-neuronal cells of the adult central nervous system that synthesize a range of molecules enabling them to adapt rapidly and successfully to a changing environment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Distributed and parallel databases 4 (1996), S. 229-247 
    ISSN: 1573-7578
    Keywords: Workflow ; Disconnected Operation ; Mobile Computing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Workflow Management Systems (WFMSs) automate the execution of business processes in environments encompassing large numbers of users distributed over a wide geographic area and using heterogeneous resources. Current implementations allow the definition and controlled execution of complex and long lived business processes as the basis for an enterprise-wide collaborative system but, in most cases, the autonomy of the users is greatly restricted due to architectural and design considerations. In particular, existing systems are built around a centralized server. As a result, users need to maintain an uninterrupted connection with the server to perform the different tasks assigned to them. This is a severe restriction, especially when considering the emergence of mobile computing, and the increase in use of laptops and small computers which are connected to the network only occasionally and which will, undoubtedly, be the tool of choice for many users. This paper addresses the problem of supporting disconnected workflow clients in large workflow management systems while still preserving the correctness of the overall execution and allowing coordinated interactions between the different users regardless of their location.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Distributed and parallel databases 3 (1995), S. 5-35 
    ISSN: 1573-7578
    Keywords: Partitioned data ; distributed databases ; concurrency control ; recovery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract In many distributed databases “locality of reference” is crucial to achieve acceptable performance. However, the purpose of data distribution is to spread the data among several remote sites. One way to solve this contradiction is to use partitioned data techniques. Instead of accessing the entire data, a site works on a fraction that is made locally available, thereby increasing the site's autonomy. We present a theory of partitioned data that formalizes the concept and establishes the basis to develop a correctness criterion and a concurrency control protocol for partitioned databases. Set-serializability is proposed as a correctness criterion and we suggest an implementation that integrates partitioned and non-partitioned data. To complete this study, the policies required in a real implementation are also analyzed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...