bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Structures of Cycloalkylidene‐Bridged Cyclopentadienyl Metallocene Catalysts: Effects of the Bridges of Ansa‐Metallocene Complexes on the Catalytic Activity for Ethylene Polymerization
Authors: Wang Baiquan , Mu Bin , Deng Xiaobin , Cui Huiling , Xu Shansheng , Zhou Xiuzhong , Zou Fenglou , Li Yang , Yang Ling , Li Yufei , Hu Youliang
Published: December 2004

A series of cycloalkylidene‐bridged cyclopentadienyl metallocene complexes, [(CH2)nC(C5H4)2MCl2] (M = Ti, n = 4 (4), 5 (5), 6 (6); M = Zr, n = 4 (7), 5 (8), 6 (9); M = Hf, n = 4 (10), 5 (11), 6 (12)), have been synthesized and applied to ethylene polymerization after activation with methyl aluminoxane (MAO). The cycloalkylidene‐bridged titanocene catalysts exhibit much higher activities than the corresponding zirconocene and hafnocene analogues, and have the highest activities at higher temperatures. In comparison, the silacyclopentylidene‐bridged metallocene complexes [(CH2)4Si(C5H4)2MCl2] (M = Ti (13), Zr (14)) and isopropylene‐bridged metallocene complexes [Me2C(C5H4)2MCl2] (M = Ti (15), Zr (16)) have also been synthesized and applied to ethylene polymerization. In both cases, the titanocene complexes show much higher activities than the corresponding zirconocene analogues, especially at a lower temperature. The molecular structures of complexes 4–9 have been determined by X‐ray diffraction. The structure–activity relationships, especially the effects of the bridges of ansa‐metallocene complexes, are discussed.
Polyoxometalate‐Supported Y– and YbIII–Hydroxo/Oxo Clusters from Carbonate‐Assisted Hydrolysis
Authors: Fang Xikui , Anderson Travis M. , Benelli Cristiano , Hill Craig L.
Published: December 2004

Carbonate‐assisted hydrolysis of Y or YbIII ions in the presence of the trivacant Wells–Dawson polyoxoanion, α‐[P2W15O56]12−, produced two polyoxometalate‐supported Y– or YbIII–hydroxo/oxo clusters, which have been characterized by single‐crystal X‐ray structure determination. The structure of the Y complex consists of a distorted Y4(OH)4 cubane cluster encapsulated by two lacunary α‐[P2W15O56]12− units, while the Yb cluster features a hexametallic core centered around a μ6‐oxo atom with each ${{\rm Yb}{{{\rm III}\hfill \atop 3\hfill}}}$ triangular face capped by an oxo or a hydroxo group. Magnetization measurements of the ytterbium(III) derivative suggested that intermolecular dipolar exchange is present at low temperatures (below 15 K). Despite its absence in the structures themselves, control experiments show that carbonate not only functions in the hydrolysis, it also influences the structure of the complexes by complexation to yttrium and the f‐block elements.
Mit Chromatographie und Spektrometer: Forensische Toxikologie
Authors: Wildemann Holger
Published: December 2004

Die forensische Toxikologie befasst sich mit Alkohol‐, Drogen‐, Medikamentennachweisen sowie mit dem Nachweis anderer potentiell giftiger Substanzen und der Beurteilung deren Wirkung bei akuten Vergiftungen, Todesfällen und Straftaten. Als Untersuchungsmaterialen sind hierbei Blut, Serum, Urin, Mageninhalt und Haare von besonderer Bedeutung. Die Methodik der forensischen Toxikologie besteht hauptsächlich aus einem Repertoire physikalischer und chemischer Analyseprinzipien. Mittels immunologischer Testverfahren, die auf Antigen‐Antikörper‐Reaktionen basieren, können spezifisch verschiedene Stoffgruppen oder chemisch definierte Einzelsubstanzen in Körperflüssigkeiten schnell und einfach qualitativ nachgewiesen werden. Für quantitative Bestimmungen werden die Analyten angereichert und anschließend mittels GC/MS, LC/MS, HS/GC/FID oder HPLC/DAD aufgetrennt und detektiert.
Pionier der modernen Quantenchemie: Hans Hellmann
Authors: Jug Karl , Ertmer Wolfgang , Heidberg Joachim , Heinemann Manfred , Schwarz W. H. Eugen
Published: December 2004

Leben und Werk Hans Hellmanns wurden gewürdigt. Hellmann überschritt die Grenzen von der Physik zur Chemie. Er entwickelte dabei neuartige Theoreme und Methoden zur Beschreibung der chemischen Bindungen und Reaktionen, die auch heute noch Bestand haben. Seine wissenschaftliche Klarsicht und sein persönliches Schicksal sollten uns leiten und mahnen.
Brennstoffzellen: Entwicklungsstand und Anwendungen
Authors: Reiche Annette , Haufe Stefan
Published: December 2004

Brennstoffzellen haben das Potenzial, eine bedeutende Rolle in der zukünftigen Energieversorgung zu spielen. Ihre Einsatzmöglichkeiten erstrecken sich von mobilen Anwendungen über den Einsatz in der Hausenergieversorgung und der industriellen Kraft‐Wärme‐Kopplung bis hin zu Kleinstanwendungen, bei denen Brennstoffzellen als Batterie‐ und Akkuersatz für netzunabhängige Geräte dienen können. Der aktuelle Entwicklungsstand und Anwendungsmöglichkeiten werden für alle Typen von Brennstoffzellentypen dargestellt und die zugehörigen Kostenstrukturen diskutiert. Weiterhin wird ein Überblick über Verfahren zur Erzeugung bzw. Speicherung von Wasserstoff gegeben und Vorraussetzungen für eine Wasserstoffwirtschaft erörtert.
Karl Samuel Leberecht Hermann
Authors: Brandes Georg
Published: December 2004

Als Apotheker, Chemiker und Unternehmer war er einer der Begründer der chemischen Industrie in Preußen. Als Praktiker hat er in Deutschland das Leblanc‐Soda‐Verfahren eingeführt, als Theoretiker das Cadmium entdeckt und als Unternehmer in Schönebeck eine der ältesten chemischen Fabriken errichtet.
Klebstoffe im Brennpunkt der Entwicklung
Authors: Borchard‐Tuch Claudia
Published: December 2004

Ein idealer Klebstoff sollte vielfältig einsetzbar und alterungsbeständig sein. Zudem muss er extremsten Anforderungen genügen und darf der Umwelt keinen Schaden zufügen. Inzwischen ist die Forschung diesem Wunschbild sehr nahe gekommen.
Fluid flow analysis by finite element method using arbitrarily deformed elements (Proposal of the GMSR‐method)
Authors: Matsuda Y. , Shao C. , Yoshino M. , Hoshihara M. , Tanaka Y.
Published: December 2004

The generalized MSR‐method (GMSR‐method) is proposed as a finite element fluid analysis algorithm for arbitrarily deformed elements using the error analysis approach. The MSR‐method was originally developed by one of the authors in our previous research works using a modified Galerkin method (MGM) for a convection–diffusion equation and the SIMPLER‐approach. In this paper, this MGM is developed theoretically in the case of arbitrarily deformed elements using the error analysis approach. In the GMSR‐method, since the inertia term and the pressure term are considered explicitly, only symmetrical matrices appear. Hence, it helps us reduce computational memory and computation time. Moreover, artificial viscosity and diffusivity are introduced through an error analysis approach to improve the accuracy and stability. This GMSR‐method is applied for two‐ and three‐dimensional natural convection problems in a cavity. In the computations at different Rayleigh numbers, it is shown that this method gives reasonable results compared to other research works. Thus, it is found that the GMSR‐method is applicable to thermal‐fluid flow problems with complicated boundaries. Copyright © 2004 John Wiley & Sons, Ltd.
Repeated injuries dramatically affect cells of the oligodendrocyte lineage: Effects of PDGF and NT‐3 in vitro
Authors: Fressinaud Catherine
Published: December 2004

In multiple sclerosis, relapses occur and remyelination is incomplete, whereas one demyelinating lesion induced by lysophosphatidyl choline (LPC) in rats is completely remyelinated; this process is accelerated by platelet‐derived growth factor (PDGF) (Allamargot et al.: Brain Res 918:28–39,2001) and neurotrophin‐3 (NT‐3) (Jean et al.: Brain Res 972:110–118,2003). Similarly, oligodendrocyte (OL) progenitors might not be depleted by two to three episodes of toxic demyelination (Penderis et al.: Brain 126:1382–1391,2003); nevertheless this does not allow conclusions about the fate of resident cells (mature OL). As myelinated fibers per OL are constantly decreased in chronic MS plaques (Fressinaud and Jean: J Neurochem 85(suppl):100,2003), this suggests that OL decreased capability to synthesize new myelin membranes could result from successive relapses, impairing thereby remyelination. Thus, we have determined the consequences of multiple versus unique (Fressinaud and Vallat: J Neurosci Res 38:202–213,1994) LPC treatments on newborn rat brain pure OL cultures, as well as the putative pro‐remyelinating effects of PDGF and of NT‐3 in these conditions. Split (0.5 · 10−5 M, 6 h × 4) and multiple (2 · 10−5 M, 24 h × 2) LPC doses induced more cell loss than a unique treatment (2 × 10−5 M, 24 h) and there was no recovery. OL progenitors (A2B5+ cells) and differentiated (CNP+) OL were drastically decreased. Moreover, mature (MBP+) OL disappeared from these cultures, indicating that mature OL are also vulnerable to multiple insults. PDGF, as well as NT‐3, induced at least partial recovery, and enhanced OL progenitor proliferation. In cultures treated with either of these growth factors, mature OL represented one‐fourth of cells and extended numerous ramified processes and putative myelin balls. © 2004 Wiley‐Liss, Inc.
Regulation of naturally occurring antisense RNA of myosin heavy chain (MyHC) in neonatal cardiomyocytes
Authors: Luther H.P. , Bartsch H. , Morano I. , Podlowski S. , Baumann G.
Published: December 2004

Naturally occurring antisense RNA has been detected for a range of eukaryotic genes. Its abundance compared to levels of its complementary sense mRNA appears to be a factor indicating its possible regulatory function. In previous studies, we detected appreciable levels of antisense RNA against the two isoforms (α and β) of the heavy myosin‐chain (MyHC) in the myocardium of rats. If this is to play a significant role in gene expression antisense levels should vary in response to external and internal cellular influences. Recently, a bidirectional promoter located in the α/β MyHC intergenic region was described, which was proposed to regulate coordinated transcription of α‐MyHC sense and β‐MyHC antisense. To study MyHC antisense regulation in neonatal heart, we investigated cultivated myocytes stimulated with either trijodthyronin (T3) as an inductor of α‐MyHC or phenylephrine with stimulation of β‐MyHC. RNA‐quantification of sense and antisense transcripts of both isoforms was performed by real‐time RT‐PCR. Stimulation by T3 led to an induction of both sense and antisense of α‐MyHC and to a decrease of β‐MyHC sense and antisense. Phenylephrine increased sense and antisense β‐MyHC but reduced antisense α‐MyHC. The sense/antisense of α‐ and β‐MyHC ratio was unchanged compared to control. Results indicate a coregulation of sense and antisense MyHC RNA under stimulation of T3 and phenylephrine in neonatal cardiomyocytes. © 2004 Wiley‐Liss, Inc.
Effect of CD44 deficiency on in vitro and in vivo osteoclast formation
Authors: de Vries Teun J. , Schoenmaker Ton , Beertsen Wouter , van der Neut Ronald , Everts Vincent
Published: December 2004

In vitro studies have shown that CD44 is involved in the fusion process of osteoclast precursor cells. Yet, in vivo studies do not support this, since an osteopetrotic phenotype has not been described for CD44 knock‐out (CD44 k.o.) mice. This discrepancy may suggest that the role of CD44 in fusion may depend on the microenvironment of osteoclast formation. We investigated osteoclast formation of CD44 k.o. and wild‐type mice under three conditions: in vitro, both on plastic and on bone and in vivo by analyzing osteoclast number, and size in long bones from wild‐type and CD44 k.o. mice. Bone marrow cells from wild‐type and CD44 k.o. mice were analyzed for their capacity to form osteoclasts on plastic and on bone in the presence of macrophage colony stimulating factor (M‐CSF) and receptor activator of NF‐kB ligand (RANKL). On plastic, the number of multinucleated tartrate resistant acid phosphatase (TRAP) positive cells in CD44 k.o. cultures was twofold higher than in wild‐type cultures. On bone, however, equal numbers of osteoclasts were formed. Interestingly, the total number of osteoclasts formed on bone proved to be higher than on plastic for both genotypes, strongly suggesting that osteoclastogenesis was stimulated by the bone surface, and that CD44 is not required for osteoclast formation on bone. Functional analyses showed that bone resorption was similar for both genotypes. We further studied the osteoclastogenic potential of wild‐type bone marrow cells in the presence of CD44 blocking antibodies. Osteoclastogenesis was not affected by these antibodies, a further indication that CD44 is not required for the formation of multinucleated cells. Finally, we analyzed the in vivo formation of osteoclasts by analyzing long bones from wild‐type and CD44 k.o. mice. Morphometric analysis revealed no difference in osteoclast number, nor in number of nuclei per osteoclasts or in osteoclast size. Our in vitro experiments on plastic showed an enhanced formation of osteoclasts in the absence of CD44, thus suggesting that CD44 has an inhibitory effect on osteoclastogenesis. However, when osteoclasts were generated on bone, no differences in number of multinucleated cells nor in bone resorption were seen. These observations are in agreement with in vivo osteoclast characteristics, where no differences between wild‐type and CD44 k.o. bones were encountered. Therefore, the modulating role of CD44 in osteoclast formation appears to depend on the microenvironment. J. Cell. Biochem. 94: 954–966, 2005. © 2004 Wiley‐Liss, Inc.
Thermotolerance of pulp cells and phagocytosis of apoptotic pulp cells by surviving pulp cells following heat stress
Authors: Kitamura Chiaki , Nishihara Tatsuji , Ueno Yoshiko , Nagayoshi Masato , Kasugai Shohei , Terashita Masamichi
Published: December 2004

Apoptosis is known to be associated with wound healing and regeneration of dental pulp. We examined the effects of heat stress on clonal dental pulp cell line (RPC‐C2A cells) to clarify the pulp wound healing process. RPC‐C2A cells were exposed to heat stress at 43°C for 45 min. After several time intervals, the inhibition of cell proliferation and apoptosis induction were analyzed by cell viability assay, DNA gel electrophoresis, nuclear staining, and terminal deoxynucleotidyl transferase mediated labeling assay. RPC‐C2A cells showed the thermotolerance following heat stress. We found that apoptosis was induced in some RPC‐C2A cells, whereas others remained alive, and observed the engulfment of apoptotic cells by scavenger‐like RPC‐C2A cells following heat stress. We also analyzed the phagocytotic activity of RPC‐C2A cells and found that they had an ability to engulf apoptotic RPC‐C2A cells, which was stimulated by heat stress. These results suggest that heat stress induces apoptosis of RPC‐C2A cells, which are phagocytosed by the surviving RPC‐C2A cells. © 2004 Wiley‐Liss, Inc.
Differentiation of HL‐60 cells to granulocytes involves regulation of select diacylglycerol kinases (DGKs)
Authors: Batista Eraldo L. , Warbington Martha , Badwey John A. , Van Dyke Thomas E.
Published: December 2004

Diacylglycerol Kinases (DGKs) are a family of enzymes that regulate the levels of different pools of diacylglycerol (DAG), affecting DAG‐mediated signal transduction. Since DAG is known to play several important regulatory roles in granulocyte physiology, we investigated the expression pattern of DGK isoforms throughout differentiation of HL‐60 cells to granulocytes. HL‐60 cells were incubated with 1.25% dimethyl‐sulfoxide (DMSO) to initiate differentiation and total RNA isolated at different time points. DGK expression was assessed through Northern blot, end‐point PCR, and real‐time PCR. The non‐selective inhibitors R59022 and R59949 were used to block DGK at different time points throughout differentiation. CD11b and GPI‐80, reactive oxygen species (ROS) generation, changes in the cell cycle, and apoptosis were used as markers of differentiation. Of the nine isoforms of DGK evaluated (α, δ, ε, γ, ζ, β, θ, ι, η), only five (α, δ, ε, γ, and ζ) were expressed in HL‐60 cells. DGKα was virtually absent in non‐differentiated cells, but was markedly upregulated throughout differentiation. The other isoforms (δ, ε, γ, and ζ) were expressed in undifferentiated HL‐60 cells but were substantially decreased throughout differentiation. Non‐selective blocking of DGK with R59022 and R59949 led to acceleration of differentiation, reducing the time necessary to observe upregulation of CD11b, GPI‐80 and generation of ROS by 50%. Likewise, the cell cycle was disrupted when DGK isoforms were inhibited. These results provide evidence that DGK levels are dynamically regulated throughout differentiation and that expression of DGKs play an important regulatory function during the differentiation of neutrophils. © 2004 Wiley‐Liss, Inc.
Creatine enhances survival of glutamate‐treated neuronal/glial cells, modulates Ras/NF‐κB signaling, and increases the generation of reactive oxygen species
Authors: Juravleva Elena , Barbakadze Tamar , Mikeladze David , Kekelidze Téa
Published: December 2004

The protective effects of creatine against glutamate cytotoxicity have been demonstrated in neuronal cells and animal models of neurodegenerative diseases. The mechanisms underlying creatine neuroprotection against glutamate‐induced cell death are understood poorly. For the first time, we demonstrate a correlation between the protective effect of creatine and the modulation of Ras‐mediated redox‐dependent signaling pathways, which involve nuclear factor κB (NF‐κB) and reactive oxygen species (ROS). In primary cerebrocortical cultures of mixed neurons and glia, creatine significantly reduced glutamate‐induced cell death. The increase in cell survival was accompanied by increased generation of oxygen radicals and decreased levels of farnesylated Ras and IκB, an inhibitor of NF‐κB. Non‐farnesylated Ras and ROS‐dependent activation of NF‐κB have been shown to promote neuronal survival. Our data suggest that creatine may enhance survival signaling via activation of the Ras/NF‐κB system. Possible mechanisms underlying the protective effect of creatine are discussed, including normalization of cellular GTP levels. © 2004 Wiley‐Liss, Inc.
Activity of the lactate–alanine shuttle is independent of glutamate–glutamine cycle activity in cerebellar neuronal–astrocytic cultures
Authors: Bak Lasse K. , Sickmann Helle M. , Schousboe Arne , Waagepetersen Helle S.
Published: December 2004

The glutamate–glutamine cycle describes the neuronal release of glutamate into the synaptic cleft, astrocytic uptake, and conversion into glutamine, followed by release for use as a neuronal glutamate precursor. This only explains the fate of the carbon atoms, however, and not that of the ammonia. Recently, a role for alanine has been proposed in transfer of ammonia between glutamatergic neurons and astrocytes, denoted the lactate–alanine shuttle (Waagepetersen et al. [ 2000] J. Neurochem. 75:471–479). The role of alanine in this context has been studied further using cerebellar neuronal cultures and corresponding neuronal–astrocytic cocultures. A superfusion paradigm was used to induce repetitively vesicular glutamate release by N‐methyl‐D‐aspartate (NMDA) in the neurons, allowing the relative activity dependency of the lactate–alanine shuttle to be assessed. [15N]Alanine (0.2 mM), [2‐15N]/[5‐15N]glutamine (0.25 mM), and [15N]ammonia (0.3 mM) were used as precursors and cell extracts were analyzed by mass spectrometry. Labeling from [15N]alanine in glutamine, aspartate, and glutamate in cerebellar cocultures was independent of depolarization of the neurons. Employing glutamine with the amino group labeled ([2‐15N]glutamine) as the precursor, an activity‐dependent increase in the labeling of both glutamate and aspartate (but not alanine) was observed in the cerebellar neurons. When the amide group of glutamine was labeled ([5‐15N]glutamine), no labeling could be detected in the analyzed metabolites. Altogether, the results of this study support the existence of the lactate–alanine shuttle and the associated glutamate–glutamine cycle. No direct coupling of the two shuttles was observed, however, and only the glutamate–glutamine cycle seemed activity dependent. © 2004 Wiley‐Liss, Inc.
Glutamate‐mediated influx of extracellular Ca2+ is coupled with reactive oxygen species generation in cultured hippocampal neurons but not in astrocytes
Authors: Kahlert Stefan , Zündorf Gregor , Reiser Georg
Published: December 2004

Generation of reactive oxygen species (ROS) in brain tissue leads to neurodegeneration. The major source of ROS is the mitochondrial respiratory chain. We studied regulation of Ca2+ level, mitochondrial potential, and ROS generation in defined mixed hippocampal cell cultures exposed to glutamate (100 μM). Recordings were made from individually identified astrocytes and neurons to compare the physiologic responses in both cell types. Neurons identified by synaptotagmin immunoreactivity were characterized functionally by the fast Ca2+ increase with K+ (50 mM) stimulation, and the astrocytes identified by glial fibrillary acidic protein (GFAP) staining had the functional characteristic of a transient Ca2+ peak in response to ATP (10 μM) stimulation. We found that the glutamate‐mediated Ca2+ response in neurons is due largely to influx of extracellular Ca2+. This is consistent with our finding that in cultured hippocampal neurons, stores depending on the activity of the sarcoendoplasmic reticulum Ca2+ ATPase (SERCA) pump had a low Ca2+ content, regardless of whether the neurons were challenged or not with K+ before applying the SERCA inhibitor cyclopiazonic acid (CPA). Astrocytes displayed a large CPA‐mediated Ca2+ response, indicating a high level of Ca2+ load in the stores in astrocytes. Importantly, the rise in ROS generation due to glutamate application was cell‐type specific. In neurons, glutamate induced a marked rise in generation of ROS, but not in astrocytes. In both astrocytes and neurons, the mitochondrial potential was increased in response to glutamate challenge. We conclude that in neurons, Ca2+ influx accounts for the increased ROS generation in response to glutamate. This might explain the high vulnerability of neurons to glutamate challenge compared to the vulnerability of astrocytes. The high resistance of astrocytes is accompanied by an efficient downregulation of cytosolic Ca2+, which is not found in neurons. © 2004 Wiley‐Liss, Inc.
Whither franchising? The case of Avis Europe PLC
Authors: Jacobsen Lowell R.
Published: December 2004

This case study of Avis Europe PLC examines the diminished role of franchising in the vehicle leasing firm's achievement of market dominance in Europe. Market maturity, industry consolidation, adoption of centralised, efficiency‐oriented technologies, and strategic alliances are the principal factors in accounting for the decline in the reliance on franchisees for local entrepreneurship and market expansion. Though many theories of franchising find at least some support in this study, the life cycle or ownership redirection explanation proves particularly compelling. Copyright © 2004 John Wiley & Sons, Ltd.
A conforming unified finite element formulation for the vibration of thick beams and frames
Authors: Hirdaris Spyridon E. , Lees Arthur W.
Published: December 2004

Beams and frames are common features in many engineering structures and in this paper an approach is given to model their dynamic behaviour adequately. Whilst the eigen‐frequencies of continuous systems comprising of slender beams can be identified, in most cases of practical interest, by means of Euler or Timoshenko beam theory, for structures comprising of thick beam models this is not necessarily true since such idealizations constrain the cross‐sections to remain planar. This paper suggests an alternative approach by means of a unified fully conforming plane stress rectangular finite element which is believed to allow for more realistic representation of the shear effects and hence the strain field around the joints of such structures. The usefulness and functionality of this improved numerical approach is explored via comparison against a non‐conforming two‐dimensional plate as well as one‐dimensional Euler–Bernoulli and Timoshenko finite element formulations corresponding to a variety of beam aspect ratios representing the structures of a rotor and a portal frame. The idealization is shown to be particularly advantageous for simulating the effects of shear distortion where beams join at right angles and the transverse forces in one member interact with the extensional forces of the adjoining structure. Copyright © 2004 John Wiley & Sons, Ltd.
Poly(butylene terephthalate)–clay nanocomposites prepared by melt intercalation: morphology and thermomechanical properties
Authors: Chang Young‐Wook , Kim Suksoo , Kyung Youngbin
Published: December 2004

Nanocomposites based on poly(butylene terephthalate) (PBT) and an organoclay (Cloisite 30B) were prepared by melt blending using a twin‐screw extruder. Two kinds of PBTs, ie PBT‐A and PBT‐B, with different inherent viscosities (ηinh), were used for this study (ηinh of PBT‐A and PBT‐B were 0.74 and 1.48, respectively). Dispersion of the clay layers in the PBT nanocomposites was characterized by using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile and dynamic mechanical properties and non‐isothermal crystallization temperatures of the nanocomposites were also examined. Nanocomposites based on the higher‐viscosity PBT (PBT‐B) showed a higher degree of exfoliation of the clay and a higher reinforcing effect when compared to the composites based on the lower‐viscosity PBT (PBT‐A). The clay nanolayers dispersed in PBT matrices lead to increases in the non‐isothermal crystallization temperatures of the PBTs, with such increases being more significant for the PBT‐B nanocomposites than for the PBT‐A nanoocomposites. Copyright © 2004 Society of Chemical Industry
Synthesis and properties of poly(isobutyl methacrylate‐co‐butanediol dimethacrylate‐co‐methacryl polyhedral oligomeric silsesquioxane) nanocomposites
Authors: Li Gui Zhi , Cho Hosouk , Wang Lichang , Toghiani Hossein , Pittman Charles U.
Published: December 2004

Poly[isobutyl methacrylate‐co‐butanediol dimethacrylate‐co‐3‐methacrylylpropylheptaisobutyl‐T8‐polyhedral oligomeric silsesquioxane] [P(iBMA‐co‐BDMA‐co‐MA‐POSS)] nanocomposites with different crosslink densities and different polyhedral oligomeric silsesquioxane (MA‐POSS) percentages (5, 10, 15, 20, and 30 wt %) were synthesized by radical‐initiated terpolymerization. Linear [P(iBMA‐co‐MA‐POSS)] copolymers were also prepared. The viscoelastic properties and morphologies were studied by dynamic mechanical thermal analysis, confocal microscopy, and transmission electron microscopy (TEM). The viscoelastic properties depended on the crosslink density. The dependence of viscoelastic properties on MA‐POSS content at a low BDMA loading (1 wt %) was similar to that of linear P(iBMA‐co‐MA‐POSS) copolymers. P(iBMA‐co‐1 wt % BDMA‐co‐10 wt % MA‐POSS) exhibited the highest dynamic storage modulus (E′) values in the rubbery region of this series. The 30 wt % MA‐POSS nanocomposites with 1 wt % BDMA exhibited the lowest E′. However, the E′ values in the rubbery region for P(iBMA‐co‐3 wt % BDMA‐co‐MA‐POSS) nanocomposites with 15 and 30 wt % MA‐POSS were higher than those of the parent P(iBMA‐co‐3 wt % BDMA) resin. MA‐POSS raised the E′ values of all P(iBMA‐co‐ 5 wt % BDMA‐co‐MA‐POSS) nanocomposites in the rubbery region above those of P(iBMA‐co‐5 wt % BDMA), but MA‐POSS loadings < 15 wt % had little influence on glass‐transition temperatures (Tg's) and slightly reduced Tg values with 20 or 30 wt % POSS. Heating history had little influence on viscoelastic properties. No POSS aggregates were observed for the P(iBMA‐co‐1 wt % BDMA‐co‐MA‐POSS) nanocomposites by TEM. POSS‐rich particles with diameters of several micrometers were present in the nanocomposites with 3 or 5 wt % BDMA. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 355–372, 2005
What are the needs of patients diagnosed with cancer?
Authors: Baum Michael
Published: December 2004

No absract
Mixture and mixture–process variable experiments for pharmaceutical applications
Authors: Anderson‐Cook Christine M. , Goldfarb Heidi B. , Borror Connie M. , Montgomery Douglas C. , Canter Kelly G. , Twist John N.
Published: December 2004

Many experiments in research and development in the pharmaceutical industry involve mixture components. These are experiments in which the experimental factors are the ingredients of a mixture and the response variable is a function of the relative proportion of each ingredient, not its absolute amount. Thus the mixture ingredients cannot be varied independently. A common variation of the mixture experiment occurs when there are also one or more process factors that can be varied independently of each other and of the mixture components, leading to a mixture–process variable experiment. We discuss the design and analysis of these types of experiments, using tablet formulation as an example. Our objective is to encourage greater utilization of these techniques in pharmaceutical research and development. Copyright © 2004 John Wiley & Sons Ltd.
Calcium signaling via voltage‐dependent L‐type Ca2+ channels
Authors: Naguro Isao , Adachi‐Akahane Satomi , Ichijo Hidenori
Published: December 2004

In excitable cells such as muscles and neurons, the voltage‐dependent L‐type Ca2+ channel is one of the most important pathways for Ca2+ influx from extracellular space in response to the cell membrane depolarization. Ca2+ ion through this channel works as a Ca2+ signal that regulates fast (on time scale of milliseconds; e.g. muscle contraction) and long‐term (on a time scale of days or weeks; e.g. gene expression) cellular responses. Many important signal molecules are activated via Ca2+ signal, such as Ca2+‐dependent protease (calpain), calcium/calmodulin dependent kinases (CaMKs), phosphatase (calcineurin), and mitogen‐activated protein kinases (MAPKs). They are activated by temporally and spatially restricted Ca2+ signals, thus strictly regulated in native tissues. Many kinds of Ca2+ channels are involved in the rise of the intracellular Ca2+ concentration. They are not mere routes of Ca2+ influx but also machineries that decide which specific signal cascade should be activated. Recently, the molecular mechanisms by which Ca2+ influx through L‐type Ca2+ channels can activate specific signal cascades have been clarified. In this review, we describe the role of Ca2+ signaling via L‐type Ca2+ channels particularly in cardiac myocytes and neurons with emphasis on the mechanisms underlying the activation of the specific Ca2+ signals by the L‐type Ca2+ channel machinery.
Using entertainment media to inform student affairs teaching and practice related to counseling skills
Authors: Taub Deborah J. , Forney Deanna S.
Published: December 2004

Ways to use films, television programs, popular music, and popular books to teach counseling skills are described.
Ionengestützte Beschichtungsprozesse in situ kontrollieren. Ion assisted deposition processes: in situ control
Authors: Ehlers Henrik , Groß Tobias , Lappschies Marc , Ristau Detlev
Published: December 2004

Ionengestützte Beschichtungsprozesse für optische Präzisionskomponenten weisen insbesondere im nahen und mittleren infraroten Spektralbereich ein hohes Potenzial auf. Die vorgestellten Ergebnisse belegen das wichtige Kriterium eines minimierten Wassereinbaus in den Schichtstrukturen sowohl durch Messungen der optischen Verluste im Wellenlängenbereich um 3 μm als auch durch die Bestimmung der spektralen Stabilität der Optiken. Der Einsatz eines in situ Monitors, der breitbandige Transmissionsmessungen direkt am Produkt ermöglicht, liefert zudem eine umfangreiche Datenbasis für die Prozessanalyse und –entwicklung. So stehen zusätzliche Informationen über das Aufwachsverhalten, die Vakuum‐Luft‐Shift sowie über Schichtinhomogenitäten zur Verfügung. Die Verknüpfung des in situ Monitors mit der Anlagensteuerung ergibt ein automatisiertes System für die Prozesskontrolle, das auf einer präzisen Bestimmung der Schichtdicke aufsetzt und eine Ausgangsbasis für das Rapid Prototyping komplexer Schichtsysteme darstellt. Hierbei kann, im Gegensatz zu Standardmonitorstrategien, auf Testbeschichtungen und Kalibrationsfaktoren verzichtet werden. Mit der vorgestellten Kombination des stabilen ionengestützten Beschichtungsprozesses und des in situ Monitors konnte die Herstellung anspruchsvoller NIR‐/ MIR‐Schichtsysteme bei einer hohen Reproduzierbarkeit automatisiert werden.
Das 6. Rahmenprogramm der EU – Chance und Herausforderung für die Industrie. The 6th Framework programme of the EC – chance and challenge for industry
Authors: Wey Karin
Published: December 2004

Im November 2002 wurde das 6. Forschungsrahmenprogramm 2002 bis 2006 offiziell eröffnet. Es ist mit insgesamt 17,5 Milliarden Euro ausgestattet, was eine Steigerung von 17 % gegenüber seinem Vorgängerprogramm bedeutet. Wie auch seine Vorgängerprogramme, hat das 6. Forschungsrahmenprogramm (FRP) das Ziel, die wissenschaftlichen und technologischen Grundlagen der Industrie der Gemeinschaft zu stärken und die Entwicklung ihrer internationalen Wettbewerbsfähigkeit zu fördern. Darüber hinaus soll das 6. FRP einen Beitrag zur Schaffung des Europäischen Forschungsraums und zur Innovation leisten. Durch veränderte Randbedingungen und neue Möglichkeiten, Projektanträge einzureichen, ist es jedoch schwieriger geworden, von den prall gefüllten Fördertöpfen der EU zu partizipieren.

Der Artikel gibt eine Übersicht über die Struktur und die administrativen Randbedingungen der Förderungen und zeigt Fördermöglichkeiten für den Bereich „Nanotechnologie, Werkstoffe und Produktion”︁ auf.
2‐Ketoglutarate dehydrogenase deficiency, a rare cause of primary hyperlactataemia: Report of a new case
Authors: Guffon N. , Lopez‐Mediavilla C. , Dumoulin R. , Mousson B. , Godinot C. , Carrier H. , Collombet J. M. , Divry P. , Mathieu M. , Guibaud P.
Published: December 2004

Two new familial cases of 2‐ketoglutarate dehydrogenase (2‐KGD) deficiency are reported: a girl who died at 10 years and a boy, still alive at 4 years, born to consanguineous parents. The cases developed progressively severe encephalopathy with axial hypotonia, psychotic behaviour, pyramidal symptoms and failure to thrive. Both children exhibited permanent lactic acidosis with acute episodes during emotional stress and various infections, associated with elevated lactate/pyruvate (L/P) ratio and slightly decreased ketone body ratio in plasma. In fibroblasts, the L/P ratio was greatly increased in the boy. No respiratory chain complex deficiency could be demonstrated in cultured fibroblasts or in mitochondria isolated from a muscle biopsy performed on the boy. In muscle isolated mitochondria, a progressive decrease of the rate of glutamate oxidation was observed after ADP addition; the rate of 2‐ketoglutarate oxidation was low in the absence of ADP and did not increase after ADP addition. 2‐KGD deficiency was demonstrated in fibroblasts from both children and in the boy's muscle and myoblasts. The 2‐KGD complex is composed of three separate enzymes: E1, E2 and E3. We could demonstrate in our patient that the E1 and E3 subunits were normal, suggesting that the E2 component could be responsible for the defect.
Reliable prenatal diagnosis of Canavan disease (aspartoacylase deficiency): Comparison of enzymatic and metabolite analysis
Authors: Bennett M. J. , Gibson K. M. , Sherwood W. G. , Divry P. , Rolland M. O. , Elpeleg O. N. , Rinaldo P. , Jakobs C.
Published: December 2004

Prenatal diagnosis has been undertaken in 17 pregnancies in 15 families at risk for aspartoacylase deficiency. Amniocentesis was at 14–18 weeks gestation followed by measurement of amniotic fluidN‐acetyl‐l‐aspartate (NAA) levels in all pregnancies and amniocyte aspartoacylase activity in most pregnancies. In one case amniocentesis was performed at 11 weeks gestation in conjunction with chorionic villus sampling. At 14–18 weeks of gestation, control levels of NAA were 0.30–2.55 µmol/L. The fetus was predicted to be affected in 8 of the pregnancies, 4 of which were confirmed by enzyme analysis on fetal tissue and 2 by the clinical and metabolic expression of Canavan disease in a newborn. In two cases there was no fetal tissue available for enzyme confirmation. One of these had the highest amniotic fluid NAA level (8.68 µmol/L) and in the other pregnancy there were two amniocenteses, both with markedly elevated levels. Of 9 fetuses predicted to be normal, 8 newborns were clinically and biochemically normal. A single case with amniotic fluid NAA in the normal range (1.56 µmol/L, measured in one laboratory only) resulted in an aborted fetus in whom aspartoacylase was deficient in cultured skin fibroblasts. We propose that amniotic fluid NAA levels remain the best predictor of an affected fetus and recommend that the assay be performed in multiple laboratories.
Prenatal analysis in two suspected cases of glutathione synthetase deficiency
Authors: Erasmus E. , Mienie L. J. , de Vries W. N. , de Wet W. J. , Carlsson B. , Larsson A.
Published: December 2004

Prenatal diagnosis was performed in a family affected by generalized glutathione synthetase deficiency. The disorder is transmitted by autosomal recessive inheritance. The first child born in this family died of the disorder at 6 weeks of age. Prenatal diagnosis was performed in two subsequent pregnancies. Amniotic fluid samples were collected by amniocentesis in the 16th and 17th weeks of pregnancy, respectively. In the case of the second pregnancy the concentration of 5‐oxoproline in the amniotic fluid was measured by stable isotope dilution, while both stable isotope dilution and glutathione synthetase activity measurements were employed in the prenatal analysis of the third pregnancy. The 5‐oxoproline concentration in the second pregnancy was even lower than that of the controls and in the case of the third pregnancy the results fell within the control range. The second pregnancy resulted in the birth of a clinically healthy girl, and the outcome of 5‐oxoproline concentration in a urine sample taken just after birth confirmed the unaffected state. The third pregnancy resulted in the birth of a healthy boy at term, and the 5‐oxoproline concentration in his urine and the glutathione synthetase activity in haemolysates were determined. The results confirmed that this infant was also unaffected and he apparently had two normal alleles for the enzyme.
Late Quaternary Climates of Australia and New Guinea
Authors: Bowler J.M. , Hope G.S. , Jennings J.N. , Singh G. , Walker D.
Published: December 2004

Between 60,000 and 40,000 B.P., northeastern Queensland, south New South Wales, and southeastern South Australia were drier than at present. From 40,000–30,000 B.P. a colder climate than at present is indicated from one New Guinea area. Dryness became even more accentuated in northeastern Queensland, whereas many lakes filled up in the southern mainland, probably because of increasing precipitation effectiveness there. Before the end of this period colder conditions than now were already giving rise to slope instability in the Snowy Mountains of New South Wales.

The period of 25,000–15,000 B.P. saw the greatest lowering of the New Guinea treeline, reaching an extreme at 17,000 B.P. when glaciers also achieved their maximum extent. This was the time of extensive glaciation in Tasmania and small glaciers formed in the Snowy Mountains. Estimates of the lowering of mean annual temperature range from 6°–10°C. Northeastern Queensland experienced its driest Late Quaternary climate; lakes were contracting throughout the southern mainland and the final phase of substantial desert dune building took place before the period ended.

In the Snowy Mountains ice retreat began before 20,000 B.P., as did the construction of clay dunes in the southern semi-arid belt, a process demanding higher temperatures. However, in New Guinea and Tasmania ice retreat and treeline rise did not begin till after 15,000 B.P. Temperatures rose rapidly and everywhere most of the ice had gone by 10,000 B.P., when some lakes filled up in southern Australia, implying an increase in absolute precipitation.

In the last 10,000 years climate has been relatively stable although there are some indications that temperature and rainfall were marginally higher than now between 8000 and 5000 B.P. Since then, lake levels have oscillated; a brief, limited resumption of periglacial activity took place in the Snowy Mountains and there were small glacier advances in New Guinea.
Development of Quaternary Stratigraphy in Northeastern United States and Adjacent Canada
Authors: Flint Richard Foster
Published: December 2004

Quaternary stratigraphy in the northeastern region has developed slowly because researchers have been few and because quartzose bedrock and extensive forest have inhibited field study. The earliest stratigraphic studies antedated 1850, but in most parts of the region the stratigraphic units still recognized today were identified in the present century. Ancient and modern sequences are generalized and are shown in charts.
Heavy Minerals and the Evolution of the Modern Nile
Authors: Hassan Fekri A.
Published: December 2004

Heavy mineral analysis is a useful tool in tracing the changes in the hydrographic setting of the Nile through time. Analyses by the writer and others are presented to differentiate between a former Nilotic system, a Proto-Nile, and the modern Nile system, and to demonstrate the changes undergone by the modern Nile.

The Proto-Nile was almost totally dependent upon discharge from equatorial and sub-equatorial tributaries in East Africa and from local Sudano-Egyptian affluents. The modern Nile system, in contrast, is dominated by contributions from the Blue Nile and the Atbara River, which drain the Ethiopian Plateau. The discharge of these rivers is governed by the monsoonal rains which are responsible for the summer floods in the Lower Nile Basin. It has been generally believed that this riverine system is very recent, perhaps not much older than 20,000 years. The evidence presented in this paper indicates that the Modern Nile system was well established by the later part of the Middle Pleistocene. In its early stage, the modern Nile was characterized by greater contributions from the non-Ethiopian East African and Sudano-Egyptian tributaries than at present.
Estimates of the Position of Sea Level between 140,000 and 75,000 Years ago
Authors: Stearns Charles E.
Published: December 2004

The absolute elevations of sea level 103,000 and 82,000 years ago have been estimated as −15 and −13 m, respectively, from the present elevations of emergent reefs on Barbados (Broecker et al., 1968; Matthews, 1973; Bloom et al., 1974). The “Barbados model” requires two assumptions: (1) that sea level was +6 m 124,000 years ago, and (2) that rates of uplift on short individual traverses have been uniform during the last 125,000 years.

A test of the derived values on Barbados itself does not yield uniform rates of uplift between 124,000 and 82,000 years ago. Less reliably dated strand line features on less uplifted coasts suggest that sea level 124,000 years ago differed from sea levels 103,000 and 82,000 years ago by smaller amounts than those suggested by the “Barbados model.” Such smaller differences yield more uniform rates of uplift between 124,000 and 82,000 years ago, on New Guinea as well as on Barbados, than do the larger. The “Barbados model” is not sufficiently precise to yield close estimates of past elevations of sea level. Better values will eventually be derived from low uplift coasts, when stratigraphic and radiometric data from them have achieved the credibility of data from moderate to high uplift coasts.
Thermokarst in Siberia and Its Influence on the Development of Lowland Relief
Authors: Czudek Tadeáš , Demek Jaromiŕ
Published: December 2004

“Thermokarst” as a process is the melting of ground ice and the consequent formation of depressions. Thermokarst landforms depend on the tectonic regime of a region, the ground ice content, and the degree to which the permafrost equilibrium is disturbed. Thermokarst forms are especially prominent in the lowlands of the subnival region with permafrost. The authors distinguish two modes of thermokarst development—permafrost back-wearing and down-wearing—based on their investigations in Siberia. The first mode is characteristic of a more dissected relief. In this case permafrost back-wearing takes place and the process is characterized by development of gullies, thermocirques, and parallel retreat of steep walls with ice veins, resulting in a lower lowland level. The second mode of thermokarst development is due to permafrost melting from above and is typical of a flat undissected relief, mainly that of watershed regions. characteristic forms are depressions with steep slopes and flat floors (alases). Thermokarst valleys develop through coalescence of alases. Thermokarst processes destroy the lowland relief of large areas and create characteristic forms resulting in a lower lowland level. Thus thermokarst represents a special type of lowland development in permafrost conditions.
Slope Deposits in the Snowy Mountains, South-Eastern Australia
Authors: Costin A. B. , Polach H. A.
Published: December 2004

Slope deposits in the Snowy Mountains of south-eastern Australia have a wide distribution above 1000 m elevation on slopes between approximately 5° and 25° which are well stabilized by the existing forest vegetation. The present environment is not severe enough to initiate slope instability.

The slope deposits consist of fines with gravel and angular stones showing preferred downslope orientation, overlying a generally smooth substrate of weathered bedrock. Pockets and lenses of relatively stone-free organomineral soil containing fragments of carbonized wood sometimes occur near the interface between the slope deposits and the weathered bedrock. Fragments of the carbonized wood carefully selected from three sites in different catchment areas several kilometers apart have similar radiometric ages of between 31,000 and 34,000 years.

The properties of the slope deposits and the context of the site and climatic conditions in which they now occur point to an origin under periglacial conditions commencing 31,000–34,000 years ago, associated with deep seasonal freezing and thawing although not necessarily with permafrost. It is estimated that a substantially lower mean annual temperature, at least 8–10°C less than the present, would have been necessary to produce periglacial conditions down to 1000 m in the Snowy Mountains. On the evidence of similar slope deposits elsewhere in south-eastern Australia, this major cold period was evidently widespread.

Climatic conditions prior to the onset of the cold period appear to have been generally similar to those of today, except perhaps for rather moister and cooler summers.
Nouvelles données sur la nature et l'origine du complexe récifal côtier de la Nouvelle-Calédonie
Authors: Coudray Jean
Published: December 2004

Un forage réalisé en 1966 dans le récif-barrière de la côte sud-ouest de Nouvelle-Calédonie a traversé, avant d'atteindre un substratum éocène à la profondeur de 226 mètres, un ensemble sédimentaire carbonaté divisé en 5 grandes unités lithologiques. L'examen de ces dernières révèle la présence, dès la base, de sédiments vraisemblablement post-miocènes, d'origine peu profonde, semblant s'être déposés durant une subsidence du socle. Le récif-barrière actuel, s'élevant d'une profondeur voisine de 70 mètres, parait être lié, au contraire, à la seule influence de phénomènes glacioeustatiques datant au plus du Quaternaire moyen.