bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen zur Proteinseparation mittels magnetischer Mikrosorbentien in Kombination mit wässrigen Zweiphasen‐Systemen
Authors: Becker J. , Raffelt S. , Franzreb M. 
Published: May 2008

AbstractSowohl wässrige Zweiphasen‐Systeme als auch magnetische Mikro‐ und Nanosorbentien werden seit einigen Jahren als potenzielle Kandidaten für neuartige Aufarbeitungsprozesse biotechnologischer Produkte wie z. B. therapeutischer Proteine gehandelt. Der kombinierte Einsatz von magnetischen Sorbentien und Extraktionsphasen kann die technologische Nutzung beider Komponenten vereinfachen und bietet zudem verfahrenstechnische Möglichkeiten zur Optimierung kritischer Prozessparameter wie Selektivität und Produktivität. Im Folgenden werden ein neuartiges, aus einer derartigen Kombination hervorgegangenes, Verfahrenskonzept zur Bioproduktisolierung sowie erste experimentelle Ergebnisse vorgestellt.
Perspektiven der Biothermodynamik – Teil II. Adsorption von Proteinen
Authors: Keller J. U. 
Published: May 2008

AbstractDie Anwendung von Begriffen und Methoden der Thermodynamik der Gleichgewichte und der Vorgänge auf Systeme und Prozesse der Biotechnologie haben zur Bildung eines neuen Fachgebietes geführt, der Technischen Biothermodynamik. Der vorliegende Artikel ist der zweite einer Reihe, in der versucht wird, einen Überblick über die Grundlagen und Möglichkeiten, die dieses Gebiet dem Bioverfahrensingenieur eröffnen, zu geben und dies auch an einzelnen Beispielen zu demonstrieren. Im vorliegenden Artikel wird die Thermodynamik der Adsorption von Proteinen aus Lösungen an festen Oberflächen entwickelt. Dabei werden Gleichgewichte und Prozesse, Einkomponenten‐ und Vielkomponentensysteme von Proteinen in Lösungen betrachtet. Einige Bemerkungen zum Phänomen der Multikontakt‐Adsorption von Proteinen und der Denaturierung von Proteinen durch Adsorption beschließen den Artikel. Die Adsorption von Molekülen eines Lösungsmittels, insbesondere von Wasser auf und in Proteinen wird hier nicht besprochen sondern ist einem Folgeartikel vorbehalten.
Towards monitoring electrostatics in gas–solid fluidized beds
Authors: Demirbas Birol , Nijenhuis John , Yurteri Caner U. , Ommen J. Ruud van 
Published: May 2008

AbstractThe electrostatic charge distribution in a lab‐scale 2‐D fluidized bed of 900 µm glass beads was determined using arrays of induction probes, and the influence of relative humidity and superficial gas velocity was examined. The bubble presence, relative humidity, and superficial gas velocity were found to influence charge separation. Bipolar charging was observed; the net charge build‐up was found to be negligible. Moreover, the system was monitored by applying the attractor comparison method to the electrostatic charge signals from an induction probe. It was concluded that this approach can indeed be used to monitor changes in the electrostatic behaviour.
Magnetically assisted gas–solid fluidization in a tapered vessel: First report with observations and dimensional analysis
Authors: Hristov Jordan 
Published: May 2008

AbstractThe article presents first experimental results on gas–solid fluidization in a tapered bed in presence of an external transverse magnetic field that creates a novel branch in magnetically assisted fluidization. Phase diagrams similar to those used to describe cylindrical beds have been created to distinguish the bed regimes occurring under the action of two principle macroscopic variables such as field intensity and gas flow rate. A detailed analysis and parallelism to the bed behaviour exhibited by non‐magnetic spouted beds of cohesive particles have been performed. Principle process variables such as bed depth, field intensity, particle size, cone angle have been detected. A dimensional analysis utilizing a “pressure transform” of the initial set of variables has been applied to develop scaling relationships. Examples of scaling experimental data pertinent to the minimum spouting point and involving the magnetic granular Bond number have been developed.
Atmospheric aerosols over two sites in a southeastern region of Texas
Authors: Chiou Paul , Tang Wei , Lin Che‐Jen , Chu Hsing‐Wei , Tadmor Rafael , Ho T. C. 
Published: May 2008

AbstractSpeciated samples of PM2.5 were collected at the Bayland Park and Orange sites in Southeastern Texas by US EPA (Environmental Protection Agency) from July 2003 to August 2005. A total of 256 samples for the Bayland Park site and 293 samples for the Orange site with 52 species were measured; however, 22 species were excluded because of too many below‐detection‐limit data. Among the 22 species excluded, 19 species are common to both sites. The two data sets were analyzed by positive matrix factorization (PMF) to infer the sources of PM observed at the two sites. The analysis identified ten common source‐related factors: sulphate‐rich secondary aerosol I, sulphate‐rich secondary aerosol II, cement/carbon‐rich, wood smoke, motor vehicle/road dust, nitrate‐rich secondary aerosol, metal processing, soil, sea salt, and chloride‐depleted marine aerosol. sulphate and nitrate mainly exist as ammonium salts. The two sulphate‐rich secondary aerosols account for about 59% and 54% of the PM2.5 mass concentration at the two sites, respectively. The factor containing highest concentrations of Cl and Na was attributed to sea salt due to the proximity of the monitoring sites to the Gulf of Mexico. The chloride‐depleted marine aerosol was related to the sea salt aerosol but was identified separately due to the chlorine replacement reactions. Basically, the factor of sulphate, nitrate, and soil at the two sites showed similar chemical composition profiles and seasonal variation that reflect the regional characteristics of these sources. The regional factors showed predominantly low frequency variations, however, the area‐related and local factors showed both high and low frequency variations. Motor vehicle/road dust, sea salt, and chloride‐depleted marine aerosol were likely to be area‐related factors. Cement/carbon‐rich, wood smoke, and metal processing factor were likely to be the local sources.
Kinetic simulation of a compact reactor system for hydrogen production by steam reforming of higher hydrocarbons
Authors: Rakib M. A. , Grace J. R. , Elnashaie S. S. E. H. , Lim C. J. , Bolkan Y. G. 
Published: May 2008

AbstractA bubbling fluidized bed membrane reactor for steam reforming of higher hydrocarbons is modelled, using n‐heptane as a model component to represent steam reforming of naphtha. The reformer is modelled as a bubbling fluidized bed reactor, consisting of two pseudo phases, a dense phase and a bubble phase, both in plug flow. In situ H2 permselective membranes remove H2 continuously as a pure product, greatly enhancing the H2 yield per mole of heptane fed. A fluidized bed membrane reformer for higher hydrocarbons could give a very compact reactor system combining all the units from the pre‐reformer to the hydrogen purification system in a traditional steam reforming plant into a single unit.
Overview and some issues related to co‐firing biomass and coal
Authors: Dai Jianjun , Sokhansanj Shahab , Grace John R. , Bi Xiaotao , Lim C. Jim , Melin Staffan 
Published: May 2008

AbstractLow heating values, variable chemical compositions, peculiar physical properties, high investment cost and insecurity of biomass feedstocks supply limit the applications of biomass for energy and other processes. Co‐firing biomass and coal has potential for the development of biomass‐to‐energy capacity with significant economic, environmental, and social benefits. However, co‐firing is not straightforward, and some questions need to be addressed due to the differences in chemical compositions and physical properties of biomass and coal. This paper highlights key issues related to co‐firing, including reactor types, feeding, hydrodynamics, ash sintering, fouling, and corrosion, based on previous studies, as well as calculations and analysis. Direct co‐firing is the most common option for biomass and coal co‐firing currently, mostly due to relatively low investment needed to turn existing coal power plants into co‐firing plants. For direct co‐firing, the physical characteristics and chemical compositions of the fuel entering the combustors or gasifiers are critical to an optimum operation. Any biomass mixed with coal needs to have acceptable physical properties. More research is needed on co‐firing biomass and coal, including work on: preparation, handling, storage, and feeding of biomass feedstocks (e.g. drying, torrefaction, pelletization); co‐firing mechanisms; hydrodynamic analysis of co‐firing combustors and gasifiers; boiler/gasifier capacity, slagging, fouling, corrosion, efficiency, reliability, fuel flexibility; lower emissions and gas cleaning; catalyst poisoning; investment and operating costs.
Synthetic Ca‐based solid sorbents suitable for capturing CO2 in a fluidized bed
Authors: Pacciani R. , Müller C. R. , Davidson J. F. , Dennis J. S. , Hayhurst A. N. 
Published: May 2008

AbstractCoprecipitation and hydrolysis of CaO have been employed to produce Ca‐based synthetic sorbents suitable for capturing CO2 in a fluidized bed. Their composition, CO2 uptake, volume in small pores (2–200 nm) and resistance to attrition were measured and compared to those of limestone and dolomite. Sorbents produced by hydrolysis showed the highest uptake and resistance to attrition. After 20 cycles of carbonation and calcination, two sorbents exceeded the uptake of both limestone and dolomite, when subjected to the same regimes of reaction. A sorbent's uptake of CO2 was shown to be determined by the volume in pores narrower than ∼200 nm.
Characteristics of anthraquinone hydrogenation catalysts in a liquid‐solid fluidized bed
Authors: Chen Guanqun , Zhou Tao , Li Hongzhong 
Published: May 2008

AbstractThe fluidization characteristics of anthraquinone hydrogenation catalysts were investigated in a liquid–solid fluidized bed. The effects of the initial bed conditions such as particle size, bed depth‐to‐column diameter ratio and liquid density and viscosity on the fluidization behaviour, bed expansion and applicability of the Richardson–Zaki equation were studied. The results reveal a strong particle size effect on the Richardson–Zaki (R‐Z) expansion index which in general decreased as the particle diameter increased. One type of particles exhibited two distinct bed expansion behaviours, depending mainly on the bed depth‐to‐column diameter ratio, with an experimentally established boundary at $h_{\rm b}0/D \approx 1.75$. This behaviour could be attributed to increasing wall friction and a tendency to exhibit slugging. The dependence of the Richardson–Zaki exponent on the liquid dynamic viscosity confirms the classic result $n_{\rm a} = f(1/Re_{t})$.
Multi‐scale CFD simulation of operating diagram for gas–solid risers
Authors: Wang Wei , Lu Bona , Dong Weigang , Li Jinghai 
Published: May 2008

AbstractOur recently presented multi‐scale computational fluid dynamics (CFD) approach has proven to be able to capture the choking phenomena in a circulating fluidized bed (CFB). However, how to transfer this capability to assist industrial operation remains to be explored. To this end, this paper presents further simulation results over the intrinsic flow regime diagram and the operating diagram for gas–solid risers, showing the variation of flow regimes with gas velocity and solids flux as well as riser height. It is confirmed that the choking in CFB risers, characterized by the saturation carrying capacity and the coexistence of both dense and dilute flows, holds clear‐cut definition in hydrodynamics. In physics, both the choking, non‐choking transitions, and the critical point in‐between are intrinsic nature of gas–solid riser flows; they initiate as functions of gas velocity and solids flux. In engineering operation, however, their appearances vary with the riser height used. As a result, the intrinsic flow regime diagram can be defined by the combination of gas velocity and solids flux, although it is hard to obtain in practice owing to the limitation of riser height. The operating diagram of a CFB should be, accordingly, height‐dependent in practice, demanding the riser height as a parameter besides commonly believed gas velocity and solids flux.
Application of discrete element method simulation for studying fluidization of nanoparticle agglomerates
Authors: Wang X. S. , Rahman F. , Rhodes M. J. 
Published: May 2008

AbstractThe usefulness of discrete element method simulation for studying fluidization of nanoparticle agglomerates is explored. Nanoparticle agglomerates were simulated by using solid particles of equivalent sizes and densities. Validity of the present simulation was assessed through comparisons of simulation results and experimental observations of bed expansion, characteristic fluidization behaviour, and dense‐bed settling. The simulation was then used to investigate initial bed expansion and bed uniformity under particulate fluidization conditions. The role of inter‐agglomerate interparticle force in fluidization of nanoparticle agglomerates was examined. A stability analysis originally developed for addressing the transition from particulate to bubbling fluidization for conventional particles was used for predicting the start of bubbling in fluidized beds of nanoparticle agglomerates.
Postnatal ontogeny of the transcription factor Lmx1b in the mouse central nervous system
Authors: Dai Jin‐Xia , Hu Ze‐Lan , Shi Ming , Guo Chao , Ding Yu‐Qiang 
Published: May 2008

AbstractThe expression profile of Lim homeodomain transcription factor Lmx1b in the mouse brain was investigated at different postnatal stages by immunohistochemistry and in situ hybridization. At postnatal day (P) 7, many Lmx1b‐expressing neurons were found in the posterior hypothalamic area, supramammillary nucleus, ventral premammillary nucleus, and subthalamic nucleus. In the midbrain, numerous Lmx1b‐expressing neurons were present in the substantia nigra pars compacta and ventral tegmental area. In the hindbrain, Lmx1b‐expressing neurons were primarily observed in the raphe nuclei, parabrachial nuclei, principal sensory trigeminal nucleus, nucleus of the solitary tract, and laminae I‐II of the medullary dorsal horn as well as spinal dorsal horn. Although expression levels diminished as postnatal life progressed, persistent expression throughout the first year of life was observed in many of these regions. In contrast, Lmx1b was present in a few brain regions (e.g., principal sensory trigeminal nucleus) only in early life with expression expiring by P60. Lmx1b was observed in dopaminergic neurons in the midbrain and serotonergic neurons in the hindbrain, as determined by double labeling with specific markers. In addition, we found that Lmx1b‐expressing neurons are not GABAergic, and Lmx1b was colocalized with Tlx3 in the parabrachial nuclei, principal sensory trigeminal nucleus, nucleus of the solitary tract. as well as the medullary and spinal dorsal horns, suggesting that Lmx1b‐expressing cells in these areas are excitatory neurons. Our data suggest that Lmx1b is involved in the postnatal maturation of certain types of neurons and maintenance of their normal functions in the adult brain. J. Comp. Neurol. 509:341–355, 2008. © 2008 Wiley‐Liss, Inc.
Nucleation kinetics and growth of nonlinear optical bis (dimethyl sulfoxide) manganese mercury thiocyanate single crystals
Authors: Raghavan C. M. , Sankar R. , Kumar R. Mohan , Jayavel R. 
Published: May 2008

AbstractNonlinear optical (NLO) material of bis (dimethyl sulfoxide) manganese mercury thiocyanate (MMTD) was synthesized by two step reaction method. The solubility and metastable zonewidth were experimentally determined in order to optimize the growth parameters. Bulk crystals of MMTD were grown by slow cooling and slow evaporation methods. The structure of the grown crystal was confirmed by X‐ray diffraction analysis. Presence of functional groups and the coordination of Lewis base ligand of dimethyl sulfoxide (DMSO) were confirmed by FT‐IR analysis. Optical transparency of the grown crystals was studied by UV‐Vis spectroscopy. Nonlinear optical property of the grown crystal was confirmed by Kurtz powder method. Etching studies reveal the formation of triangular hillock etch patterns, indicative of 2D nucleation mechanism. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical and structural properties of lead iodide thin films prepared by vacuum evaporation method
Authors: Ghosh T. , Bandyopadhyay S. , Roy K. K. , Kar S. , Lahiri A. K. , Maiti A. K. , Goswami K. 
Published: May 2008

AbstractThermally processed lead iodide (PbI2) thin films were prepared by the vacuum evaporation method in a constant ambient. Measured thickness of the film was verified analytically from the optical transmittance data in a wavelength range between 300 and 1600 nm. From the Tauc relation for the non‐direct inter band transition, the optical band gap of the film was found to be 2.58 eV for film thickness 300 nm. X‐ray diffraction analysis confirmed that PbI2 films are polycrystalline, having hexagonal structure. The low fluctuation in Urbach energy indicates that the grain size is quite small. The present findings are in agreement with the other results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Efficient Method for the Synthesis of Benzo[f]quinoline and Benzo[a]phenanthridine Derivatives Catalyzed by Iodine by a Three‐Component Reaction of Arenecarbaldehyde, Naphthalen‐2‐amine, and Cyclic Ketone
Authors: Wang Xiang‐Shan , Li Qing , Yao Chang‐Sheng , Tu Shu‐Jiang 
Published: May 2008

AbstractA mild, efficient, and general method for the synthesis of benzo[f]quinoline and benzo[a]phenanthridine derivatives by a three‐component reaction of arenecarbaldehyde, naphthalen‐2‐amine, and cyclic ketone using iodine as catalyst is described. A possible reaction mechanism for the formation of the product is proposed based on further experimental results.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Metal‐Containing Ionic Liquids as Efficient Catalysts for Hydroxymethylation in Water
Authors: Bica Katharina , Gaertner Peter 
Published: May 2008

AbstractThe iron‐containing ionic liquid butylmethylimidazolium tetrachloroferrate (bmim‐FeCl4) proved to be an efficient and recyclable catalyst for the hydroxymethylation of β‐keto esters using aqueous formaldehyde and a low catalyst loading of up to 0.1 mol‐% without co‐solvents or additional surfactants. An useful and high‐yielding approach to hydroxymethylated keto esters as well as to 3‐disubstitued butyrolactones via tandem hydroxymethylation–lactonization could thus be established.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Room‐Temperature Electrophilic 5‐endo‐dig Chlorocyclization of Alk‐3‐yn‐1‐ones with the Use of Pool Sanitizer: Synthesis of 3‐Chlorofurans and 5‐Chlorofuropyrimidine Nucleosides
Authors: Sniady Adam , Morreale Marco S. , Wheeler Kraig A. , Dembinski Roman 
Published: May 2008

AbstractThe 5‐endo‐dig chlorocyclization of 1,4‐disubstituted alk‐3‐yn‐1‐ones (propargylic ketones) with the use of trichloro‐s‐triazinetrione (trichloroisocyanuric acid, TCCA; 0.4 equiv.) in toluene, at room temperature, in the absence of base, provides 2,5‐disubstituted 3‐chlorofurans in high yields (79–96 %). The reaction can be accomplished by using commercially available swimming pool sanitizer. Selected 3‐chlorofuran was validated as a substrate for Suzuki–Miyaura coupling. In a similar manner, chlorocyclization of 5‐alkynyl‐2′‐deoxyuridines produces 5‐chlorofuropyrimidine nucleosides (76–83 %), which are analogues of potent anitviral agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Neurons control the expression of connexin 30 and connexin 43 in mouse cortical astrocytes
Authors: Koulakoff Annette , Ezan Pascal , Giaume Christian 
Published: May 2008

AbstractA characteristic feature of astrocytes is their high level of intercellular communication mediated by gap junctions. The two main connexins, Cx30 and Cx43, that form these junctions in astrocytes of adult brain display different developmental and regional expression, with a delayed onset of appearance for Cx30. In primary cultures of astrocytes from newborn cerebral cortex, while Cx43 is abundantly expressed, Cx30 is not detectable. In the present report, Western blot and confocal immunofluorescence analysis performed in astrocyte/neuron cocultures demonstrate that neurons upregulate the expression of Cx43 and induce that of Cx30 in subsets of astrocytes preferentially located in close proximity to neuronal soma. In Cx43 lacking astrocytes cocultured with neurons, the induction of Cx30 allows the restoration of dye coupling within islets of Cx30‐positive astrocytes, indicating that intercellular channels formed by Cx30 are functional. The upregulating effect of neurons on the expression of connexins in cortical astrocytes is independent of their electrical activity and requires tight interactions between both cell types. This effect is reversed after neuronal death induced by neurotoxic treatments. Furthermore, excitotoxic treatments triggering neuronal death in vivo lead to a downregulation of both connexins in reactive astrocytes located within the area depleted in neurons. Altogether these observations indicate that the expression of the two main astrocyte connexins is tightly regulated by neurons. © 2008 Wiley‐Liss, Inc.
Beta‐amyloid peptide stimulates endozepine release in cultured rat astrocytes through activation of N‐formyl peptide receptors
Authors: Tokay Tursonjan , Hachem Raya , Masmoudi‐Kouki Olfa , Gandolfo Pierrick , Desrues Laurence , Leprince Jerome , Castel Helene , Diallo Mickael , Amri Mohamed , Vaudry Hubert , Tonon Marie‐Christine 
Published: May 2008

AbstractAstroglial cells synthesize and release endozepines, a family of neuropeptides derived from diazepam‐binding inhibitor (DBI). The authors have recently shown that β‐amyloid peptide (Aβ) stimulates DBI gene expression and endozepine release. The purpose of this study was to determine the mechanism of action of Aβ in cultured rat astrocytes. Aβ25–35 and the N‐formyl peptide receptor (FPR) agonist N‐formyl‐Met‐Leu‐Phe (fMLF) increased the secretion of endozepines in a dose‐dependent manner with EC50 value of ≈2 μM. The stimulatory effects of Aβ25–35 and the FPR agonists fMLF and N‐formyl‐Met‐Met‐Met (fMMM) on endozepine release were abrogated by the FPR antagonist N‐t‐Boc‐Phe‐Leu‐Phe‐Leu‐Phe. In contrast, Aβ25–35 increased DBI mRNA expression through a FPR‐independent mechanism. Aβ25–35 induced a transient stimulation of cAMP formation and a sustained activation of polyphosphoinositide turnover. The stimulatory effect of Aβ25–35 on endozepine release was blocked by the adenylyl cyclase inhibitor somatostatin, the protein kinase A (PKA) inhibitor H89, the phospholipase C inhibitor U73122, the protein kinase C (PKC) inhibitor chelerythrine and the ATP binding cassette transporter blocker glyburide. Taken together, these data demonstrate for the first time that Aβ25–35 stimulates endozepine release from rat astrocytes through a FPR receptor positively coupled to PKA and PKC. © 2008 Wiley‐Liss, Inc.