bluuebunny/crossref_metadata_2025 huggingface dataset:
Preferential initiation of PC12 neurites in directions of changing substrate adhesivity
Authors: Murnane Aeneas C. , Brown Kimberly , Keith Charles H.
Published: August 2002

When PC12 cells are grown on substrates showing a gradient of nonspecific adhesion, they preferentially initiate neurites in directions of changing adhesivity, whether that change is in the direction of increasing or decreasing adhesivity. This preference for changing adhesivity is ablated both byC. difficiletoxin A, which inhibits all Rho‐family GTPases, and byC. botulinumC3 exoenzyme, which specifically inhibits Rho. © 2002 Wiley‐Liss, Inc.
Overexpression of S100β in transgenic mice does not protect from serotonergic denervation induced by 5,7‐dihydroxytryptamine
Authors: Bendotti C. , Cole S.E. , Gobbi M. , Hohmann C. , Reeves R.H.
Published: August 2002

Transgenic mice overexpressing S100β were used to examine whether the chronic elevation of this protein alters the response to selective partial serotonergic lesions produced by bilateral intracerebroventricular injections of 5,7‐dihydroxytryptamine (5,7‐DHT). Basal levels of S100β mRNA examined by in situ hybridization were two‐ to threefold higher throughout the brain in transgenic than in control mice, whereas 5‐HT levels in forebrain were similar in both. After the 5,7‐DHT‐induced lesions, no differences were found in the S100β mRNA levels in either normal or transgenic mice. At 5 and 60 days after the lesion, forebrain 5‐HT levels were reduced by 56% and 35%, respectively, in control mice and by 51% and 35%, respectively, in the transgenic mice. Analysis of the 5‐HT immunostaining showed a marked decrease of the immunoreactivity in various brain regions, which was comparable at the two intervals postlesion. One exception was the medial hypothalamus, where an almost complete disappearance of 5‐HT immunoreactivity was observed in the medial region at 5 days after lesion, followed by a marked reinnervation 60 days later. These hypothalamic changes were seen in both controls and S100β‐overexpressing transgenic mice. Quantitative analysis of the density of 5‐HT transporter sites using [3H]citalopram binding, a marker of serotonergic terminals, showed a marked decrease in different brain regions at both 5 and 60 days after 5,7‐DHT injections. No difference in basal and postlesion levels of [3H]citalopram binding was seen between transgenic and control mice. In conclusion, this study demonstrates that constitutive overexpression of S100β in transgenic mice does not modify serotonin levels during development, nor does it protect the serotonergic neurons from selective neurotoxicity or modify the serotonergic sprouting induced by partial lesion. © 2002 Wiley‐Liss, Inc.
Chronic treatment with glutaric acid induces partial tolerance to excitotoxicity in neuronal cultures from chick embryo telencephalons
Authors: Kölker Stefan , Okun Jürgen G. , Ahlemeyer Barbara , Wyse Angela T.S. , Hörster Friederike , Wajner Moacir , Kohlmüller Dirk , Mayatepek Ertan , Krieglstein Josef , Hoffmann Georg F.
Published: August 2002

Glutaryl‐CoA dehydrogenase deficiency (GDD) is characterized biochemically by an accumulation of glutaric (GA) and 3‐hydroxyglutaric (3‐OH‐GA) acids and clinically by the development of acute striatal degeneration. 3‐OH‐GA was recently shown to induce neuronal damage via N‐methyl‐D‐aspartate (NMDA) receptors. The pathogenetic role of GA, however, remains unclear. We demonstrate that GA exerts a dual action in cultured chick embryo neurons. Short‐term incubation with millimolar concentrations of GA induces a weak neuronal damage, adding to 3‐OH‐GA neurotoxicity. In contrast, chronic treatment with subtoxic, micromolar concentrations of GA results in partial tolerance to 3‐OH‐GA‐ and NMDA‐induced cell damage. A downregulation of NMDA receptors, in particular of the NR2B subunit, is critically involved in this GA‐induced effect, resulting in a reduced Ca2+ increase and generation of reactive oxygen species after acute exposure to NMDA or 3‐OH‐GA. Furthermore, GA decreases Na+/K+‐ATPase activity, which is prevented by glutathione, suggesting a modulation of NMDA receptor function via resting membrane potential and Na+‐dependent glutamate transport. In contrast, GA does not inhibit mitochondrial respiratory chain and β‐oxidation of fatty acids, virtually excluding an activation of NMDA receptors secondary to ATP depletion. These results strongly suggest that GA modulates the NMDA receptor‐mediated neurotoxicity of 3‐OH‐GA, providing an explanatory basis for the non‐linear relationship between organic acid concentrations and disease progression in GDD patients. Furthermore, GA‐induced downregulation of NMDA receptors might be involved in the delayed cerebral maturation of GDD patients, resulting in frontotemporal atrophy and a reduced opercularization, which are common neuroradiological findings in GDD patients. © 2002 Wiley‐Liss, Inc.
Mevastatin induces degeneration and decreases viability of cAMP‐induced differentiated neuroblastoma cells in culture by inhibiting proteasome activity, and mevalonic acid lactone prevents these effects
Authors: Kumar Bipin , Andreatta Cynthia , Koustas William T. , Cole William C. , Edwards‐Prasad Judith , Prasad Kedar N.
Published: August 2002

Statins with a closed‐ring structure (mevastatin, lovastatin, and simvastatin) and with an open‐ring structure (pravastatin and fluvastatin) are widely used in the human population to manage hypercholesterolemia. These statins may have neuroprotective or neurotoxic effects, but these effects remain controversial. We have utilized adenosine 3',5'‐cyclic monophosphate‐induced terminally differentiated murine neuroblastoma (NB) cells in culture as an experimental model to study the effect of statins. Results showed that mevastatin induced degenerative changes and reduced the viability of differentiated NB cells by inhibiting proteasome activity. Lactacystin, an established inhibitor of proteasome, also produced similar degenerative changes in these cells. In contrast, pravastatin neither affected the degeneration and viability of differentiated NB cells nor the proteasome activity. High‐performance liquid chromatography (HPLC) analysis of the extract obtained from mevastatin‐treated growth medium and differentiated cells revealed that about 50% of mevastatin is converted to an open‐ring structure in the growth medium; however, differentiated cells did not convert any portion of mevastatin into an open‐ring structure and accumulated only mevastatin with a closed‐ring structure. Mevalonic acid lactone by itself did not affect the viability of differentiated NB cells or the proteasome activity, but it completely prevented mevastatin‐induced degeneration and decreased viability by reducing the uptake of mevastatin and by blocking its action on proteasome activity. Mevalonic acid failed to prevent lactacystin‐induced degeneration and inhibition of proteasome activity. Our results suggest that mevastatin could act as a neurotoxic agent or neuroprotective agent, depending upon the extent of its hydrolysis to an open‐ring structure and the level of mevalonic acid. © 2002 Wiley‐Liss, Inc.
Stimulation of myelin gene expression in vitro and of sciatic nerve remyelination by interleukin‐6 receptor–interleukin‐6 chimera
Authors: Haggiag S. , Zhang P.‐L. , Slutzky G. , Shinder V. , Kumar A. , Chebath J. , Revel M.
Published: August 2002

Induction of myelin gene expression denotes the last stage of differentiation of myelinating glial cells. Following peripheral nerve transection, Schwann cells (SC) lose myelin gene expression and proliferate, resembling premyelinating embryonic SC (eSC). We show that a fusion protein of the soluble interleukin‐6 receptor to interleukin‐6 (IL6RIL6), a potent activator of the gp130 signaling receptor, is an inducer of MBP and Po gene products in rat E18 embryonic dorsal root ganglia (DRG) 3 day cultures. Cells whose growth is dependent on the IL6RIL6 chimera were isolated from DRG. These cells (designated CH cells) express Krox‐20, as do promyelinating and myelinating SC (mSC). IL6RIL6 induces Po and MBP in CH cells and their cocultures with neurons. In addition, IL6RIL6 leads to a disappearance of Pax‐3, a marker of eSC and nonmyelinating Schwann cells (nmSC). Glial fibrillary acidic protein, present in nmSC, is not significantly induced by IL6RIL6. The CH cells acquire glial morphology when exposed to IL6RIL6 and cover axons in cocultures. In a sciatic nerve‐derived SC line, IL6RIL6 also induces Po and triggers a rapid attachment along axons. In vivo administration of IL6RIL6 intraperitoneally to rats after sciatic nerve transection and resuture increases 4‐fold the number of myelinated nerve fibers (MF) measured on day 12, 2.5–5 mm distal to the suture. The stimulation by IL6RIL6 treatment is highest (7.1‐fold) at the more distant 5 mm site, and the thickness of myelin sheaths is increased. Compared to known SC growth factors, the gp130 activator IL6RIL6 appears to combine both in vitro mitogenic effects and promotion of myelin gene expression. J. Neurosci. Res. 64:564–574, 2001. © 2001 Wiley‐Liss, Inc.
Alterations in ciliary neurotrophic factor signaling in rapsyn deficient mice
Authors: Bartlett Selena E. , Banks Glen B. , Reynolds Anna J. , Waters Mike J. , Hendry Ian A. , Noakes Peter G.
Published: August 2002

Rapsyn is a key molecule involved in the formation of postsynaptic specializations at the neuromuscular junction, in its absence there are both pre‐ and post‐synaptic deficits including failure to cluster acetylcholine receptors. Recently we have documented increases in both nerve‐muscle branching and numbers of motoneurons, suggesting alterations in skeletal muscle derived trophic support for motoneurons. The aim of the present study was to evaluate the contribution of target derived trophic factors to increases in motoneuron branching and number, in rapsyn deficient mice that had their postsynaptic specializations disrupted. We have used reverse transcription‐polymerase chain reaction and Western blot to document the expression of known trophic factors and their receptors in muscle, during the period of synapse formation in rapsyn deficient mouse embryos. We found that the mRNA levels for ciliary neurotrophic factor (CNTF) was decreased in the rapsyn deficient muscles compared with litter mate controls although those for NGF, BDNF, NT‐3 and TGF‐β2 did not differ. We found that both the mRNA and the protein expression for suppressor of cytokine signaling 3 (SOCS3) decreased although janus kinase 2 (JAK2) did not change in the rapsyn deficient muscles compared with litter mate controls. These results suggest that failure to form postsynaptic specializations in rapsyn deficient mice has altered the CNTF cytokine signaling pathway within skeletal muscle, the target for motoneurons. This alteration may in part, account for the increased muscle nerve branching and motoneuron survival seen in rapsyn deficient mice. J. Neurosci. Res. 64:575–581, 2001. © 2001 Wiley‐Liss, Inc.
Human medulloblastoma cell line DEV is a potent tool to screen for factors influencing differentiation of neural stem cells
Authors: Buzanska L. , Spassky N. , Belin M.F. , Giangrande A. , Guillemot F. , Klämbt C. , Labouesse M. , Thomas J.L. , Domanska‐Janik K. , Zalc B.
Published: August 2002

The aim of our study was to investigate whether a human neural cell line could be used as a reliable screening tool to examine the functional conservation, in humans, of transcription factors involved in neuronal or glial specification in other species. Gain‐of‐function experiments were performed on DEV cells, a cell line derived from a human medulloblastoma. Genes encoding nine different transcription factors were tested for their influence on the process of specification of human DEV cells towards a neuronal or glial fate. In a first series of experiments, DEV cells were transfected with murine genes encoding transcription factors known to be involved in the neuronal differentiation cascade. Neurogenins‐1, ‐2, and ‐3; Mash‐1; and NeuroD increased the differentiation of DEV cells towards a neuronal phenotype by a factor of 2–3.5. In a second series of experiments, we tested transcription factors involved in invertebrate glial specification. In the embryonic Drosophila CNS, the development of most glial cells depends on the master regulatory gene glial cell missing (gcm). Expression of gcm in DEV cells induced a twofold increase of astrocytic and a sixfold increase of oligodendroglial cell types. Interestingly, expression of tramtrack69, which is required in all Drosophila glial cells, resulted in a fourfold increase of only the oligodendrocyte phenotype. Expression of the related tramtrack88 protein, which is not expressed in the fly glia, or the C. elegans lin26 protein showed no effect. These results show that the Drosophila transcription factor genes tested can conserve their function upon transfection into the human DEV cells, qualifying this cell line as a screening tool to analyze the mechanisms of neuronal and glial specification. J. Neurosci. Res. 65:17–23, 2001. © 2001 Wiley‐Liss, Inc.
Macrophage colony‐stimulating factor is expressed in neuron and microglia after focal brain injury
Authors: Takeuchi Akihide , Miyaishi Osamu , Kiuchi Kazutoshi , Isobe Ken‐ichi
Published: August 2002

In a previous study, we have demonstrated that damaged neurons within a boundary area around necrosis fall into delayed neuronal death owing to the cytotoxic effect of microglial nitric oxide (NO), and these neurons are finally eliminated by activated microglia. In this process, microglia are activated to release NO, increase in number, and accumulate toward the damaged area. In this study, we investigated the expression of macrophage colony‐stimulating factor (M‐CSF, also called colony stimulating factor‐1; CSF‐1) and other cytokines, which are reported to relate to activation, proliferation, or migration of microglia. The mRNA of M‐CSF arose biphasically from 30 min to 1 hr and from 6 to 72 hr after the injury, as demonstrated by semiquantitative RT‐PCR. However, another cytokine of granulocyte‐macrophage CSF (GM‐CSF) or interleukin‐3 (IL‐3), which causes proliferation of microglia in vitro, was not detected. From immunohistochemical studies, positive staining of M‐CSF was observed mainly in neuron‐specific enolase (NSE)‐positive cells from 1 to 12 hr after the injury, and after that M‐CSF became positive in Griffonia simplicifolia isolectin‐B4 (GSA‐I‐B4)‐positive cells from 24 to 72 hr in the boundary area around necrosis. These results suggest that neurons around the damaged area express M‐CSF in the early phase after injury, which may initially activate microglia, and these activated microglia also express M‐CSF later, causing further proliferation or migration of microglia themselves to eliminate damaged neurons or necrotic brain tissue. J. Neurosci. Res. 65:38–44, 2001. © 2001 Wiley‐Liss, Inc.
Neuroprotective effect of hypothermia at defined intraischemic time courses in cortical cultures
Authors: Varathan Sriranganathan , Shibuta Satoshi , Shimizu Tomoaki , Mashimo Takashi
Published: August 2002

Many experimental and clinical studies have shown that hypothermia confers cerebroprotective benefits against ischemic insults. Because of the many conflicting reports on hypothermic neuroprotection, we undertook this cellular study to identify the optimal temperature or a range of temperatures for maximal neuroprotection at different times (6–24 hr) during ischemic insults. Cultured Wistar rat cortical neurons were exposed to oxygen deprivation at defined times and temperatures (37°C normothermia, 32°C mild hypothermia, 27°C moderate hypothermia, 22°C deep hypothermia, and 17°C profound hypothermia). The survival rate of neurons was evaluated by assessing viable neurons on photomicrographs. The normothermic group demonstrated a significantly lower survival rate of cultured neurons (6 hr, 80.3% ± 2.7%; 12 hr, 56.1% ± 2.1%; 18 hr, 34.2% ± 1%; 24 hr, 18.1% ± 2.2%) compared to hypothermic groups (P < 0.001). The survival rate for the profound hypothermic group was significantly reduced (P < 0.01) compared to other hypothermic groups (at 17°C: 12 hr, 85.9% ± 2.5%, 18 hr, 74.7% ± 3.7%, 24 hr, 58.7% ± 2.7%). Almost equal survival rates were observed among mild, moderate, and deep hypothermic groups following <18 hr exposure to hypoxia, but the deep hypothermic group showed a significantly higher survival rate (84.1% ± 1.6%; P < 0.001) when subjected to hypoxia for 24 hr. In conclusion, hypothermia offers marked neuroprotection against hypoxia, but attenuation of neuronal cell death was less with profound hypothermia compared to mild, moderate, and deep hypothermia. Deep hypothermia affords maximal protection of neurons compared to mild and moderate hypothermia during long‐lasting hypoxia (>18 hr). J. Neurosci. Res. 65:583–590, 2001. © 2001 Wiley‐Liss, Inc.
Long pressure series for Barcelona (Spain). Daily reconstruction and monthly homogenization
Authors: Rodríguez R. , Barriendos M. , Jones P.D. , Martín‐Vide J. , Peña J.C.
Published: August 2002

Daily meteorological records for Barcelona, Spain, start unofficially in 1780. The records are of very good quality, although the metadata are far from complete. This study gives the general characteristics of the daily instrumental records, details of the data sources together with the reconstruction of the daily and monthly pressure series. In the second part of this paper, a separate time series made up of three (deterministic, periodic and random) components is analysed, and a methodological approach based on the cumulative deviation from the mean is then used to homogenize the monthly pressure series. Published in 2001 by John Wiley & Sons, Ltd.
Patterns of monthly rainfall shortage and excess in terms of the standardized precipitation index for Catalonia (NE Spain)
Authors: Lana X. , Serra C. , Burgueño A.
Published: August 2002

Spatial and time behaviours of rainfall shortage and excess are analysed for Catalonia (NE Spain) using a database obtained from 99 rain gauges with monthly totals collected from 1961 to 1990. The distribution of monthly amounts for each rain gauge is modelled by means of the gamma or Poisson‐gamma distributions. Then, using an equiprobable transformation, monthly amounts described with these distributions are substituted by values given by the Standardized Precipitation Index (SPI), which follows a standardized normal distribution and provides a unique pluviometric scale. After that, principal component analysis (PCA) is applied to the set of monthly SPIs. A double regionalization of the 99 rain gauges, distinguishing between episodes of rainfall shortage and excess, is achieved by taking into account the rotated factor loadings (RFL) correlating rain gauges and principal components (PC). A time classification of rainfall shortage and excess episodes is also established, considering in this case the factor scores (FS) obtained after a PCA of variables based on monthly SPIs. The spatial regionalization achieved becomes a rough picture of the different topographic domains (Pyrenees, Pre‐Pyrenees, Central Basin, Littoral and Pre‐Littoral chains and Mediterranean coast), the climatic diversity of Catalonia being enhanced by these results. The time clustering suggests a quite complex behaviour of the rainfall shortage and excess episodes. Moreover, the spatial distribution of these time clusters is very disperse, in such a way that monthly shortage and excess sometimes affect the whole of Catalonia and sometimes just a small area. Besides results obtained from PCA and clustering algorithms, it is worth noticing that the severity of the episodes increases remarkably only for rainfall shortage. In addition, an analysis of the number of rain gauges affected by monthly shortage and excess shows an interesting fact: whereas the number of rain gauges associated with a shortage has an increasing tendency, a significant decreasing tendency for excess is detected in the period 1961–1990. Copyright © 2001 Royal Meteorological Society
Rh(III) complexes of singly and doubly reduced phthalocyanine ligands generated by chemical and electrochemical reduction
Authors: CHEN M. J. , KLINGLER R. J. , RATHKE J. W.
Published: August 2002

The paramagnetic complexes ( FPc )( Me ) Rh - (4) and (FPc)( PMe 3)( Me ) Rh - (10) have been prepared by reducing ( FPc )( Me ) Rh (1) and ( FPc )( PMe 3)( Me ) Rh (2) with NaBH 4 in methanol-d4 [ FPc 2- = dianion of 1,4,8,11,15,18,22,25-octakis(trifluoromethyl)phthalocyanine]. Compounds 4 and 10 are further reduced by NaBH 4 to complexes, which are assigned to ( DFPc )( Me ) Rh - (5) and ( DFPc )( PMe 3)( Me ) Rh - (11), respectively. Based on the 1 H NMR spectra of these complexes, 4 and 10 are assigned to the Rh (III) complexes of the singly reduced radical anion FPc ·3-, while 5 and 11 are assigned to the Rh (III) complexes of the doubly reduced, antiaromatic anion DFPc 3-, which has the deuteron bonded to one of its meso nitrogens. As expected, the antiaromatic complexes 5 and 11 are not stable. At -40 °C, 5 was transformed successively into three aromatic compounds, the first of which was assigned to the ring-contracted α,β,γ-triazatetrabenzocorrole complex ( TBC )( Me ) Rh - [ TBC 3- = trianion of 3,6,10,13,17,20,24,27-octakis(trifluoromethyl)-α,β,γ-triazatetrabenzocorrole]. Cyclic voltammetry of 1 and 2 was also carried out. Two reversible one-electron reduction waves were observed for both 1 and 2.
Position isomer separation of non-peripheral substituted zinc dibenzo-di(3,4-pyrido)porphyrazines
Authors: SAKAMOTO KEIICHI , KATO TAKU , COOK MICHAEL J.
Published: August 2002

The cyclotetramerisation products from the 1,8-diazabicyclo[5,4,0]undec-7-ene catalysed reaction of a 1:1 mol mixture of 3,6-didecylphthalonitrile and 3,4-dicynopyridine in the presence of zinc chloride have been isolated by chromatography. The fractions comprise zinc octadecylphthalocyanine and compounds in which one, two, three and four pyridinoid rings replace the didecylbenzenoid moiety. The zinc bis(1,4-didecylbenzo)bis(3,4-pyrido)porphyrazine fraction was separated further into four sub-fractions and the components have been characterised by 400 MHz proton nuclear magnetic resonance spectroscopy, visible region spectroscopy, fluorescence spectroscopy and by cyclic voltammetry.
Light intensity effect on the mechanisms of tumor damage photosensitized by a substituted Zn(II)-naphthalocyanine
Authors: SHOPOVA M. , PEEVA M. , STOICHKOVA N. , JORI G. , WÖHRLE D. , PETROV G.
Published: August 2002

Cytotoxicity induced by photodynamic therapy (PDT) is connected with the phenomena of photo-oxidation. Generation of singlet oxygen and free radicals (superoxide or hydroxide) is accepted as a mechanism for the photo-oxidation action of PDT. Very little is however known about the validity of metabolitic and biochemical events observed in cell culture systems to in vivo tumor shrinkage following PDT. In the present work using the well-studied tetrabenzamido-substituted zinc (II)-naphthalocyanine ( ZnNc ) including towards pigmented melanoma, we accessed its efficacy for apoptotic processes during PDT of Lewis lung carcinoma (LLC) in mice in dependence on light intensity. Early photodynamic therapy responses were examined at 1, 3, 6, 10 and 24 h after coherent 774 nm illumination of the tumors applied 24 h after intraperitoneal (i.p.) injection of dipalmitoylphosphatidylcholine (DPPC)-liposome-incorporated 0.5 mg kg-1 b.w. ZnNc . Fluence rates of 260, 380 and 500 mW cm-2 at a fluence of 360 J cm-2 were used. Macroscopic observations showed that tumor reduction (and its eventual elimination) depends on optimal conditions for the occurring of photochemical reaction during PDT. At the same time, electron microscopy (EM) assays demonstrated strongly expressed dependence of apoptotic processes on the applied light intensities. Features of apoptotic processes were most clearly expressed at the highest used fluence rate.
Linking the North Atlantic to central Europe: a high‐resolution Holocene tephrochronological record from northern Germany
Authors: van den Bogaard Christel , Schmincke Hans‐Ulrich
Published: August 2002

A high‐resolution Holocene tephrochronology for northern Germany has been established based on systematic tephrostratigraphical analysis of three peat bogs. Microscopic volcanic ash layers have been traced and characterised petrographically and by the chemical composition of the glass shards. At least 37 ash horizons representing 16 different explosive volcanic eruptions have been identified and many can be correlated between the three sites, up to 100 km apart. The tephra layers can be related to Icelandic volcanic sources and some correlated to the eruptions of Askja 1875, Hekla 3, Hekla Selsund, Hekla 4 and Hekla 5, as well as to unspecified eruptions of Icelandic volcanic systems, e.g. Torfajökull. The source volcanoes for some tephra layers remain unidentified. Some tephra layers were known previously from the North Atlantic region (e.g. Sluggan, Glen Garry), others have not been recorded previously in the literature (e.g. microlite tephra). This study provides the first comprehensive Holocene tephrostratigraphical record for northern Germany, complementing the North Atlantic tephrostratigraphical dating framework, effectively extending it into central Europe. The study shows that Icelandic ash layers are even more widespread than hitherto thought. Copyright © 2002 John Wiley & Sons, Ltd.
Distribution of modern dinoflagellate cysts from inshore areas along the coast of southern Norway
Authors: Grøsfjeld Kari , Harland Rex
Published: August 2002

Surface sediment samples from inshore areas along the coast of Norway, from Kragerø in the south to Kristiansund in mid‐Norway, were analysed for their dinoflagellate cyst content in order to establish a modern reference data base. Ultimately these data should furnish a firm foundation for dinoflagellate cyst research in the area in terms of both their spatial and their temporal records. Our aim is to build a data base containing reference samples from the various fjords and inshore areas along the entire Norwegian coast. Dinoflagellate cysts have been recovered from all the samples studied and three main areas have been distinguished based upon their cyst assemblages; the western part of Skagerrak, the southwestern coast of Norway bordering the North Sea, and the west coast of Norway bordering the Norwegian Sea. The dinoflagellate cyst assemblages from these areas are, most probably, closely related to oceanographic parameters and reflect latitudinal or climatic trends along this stretch of the coast. Copyright © 2001 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy of 1H‐1,2,3‐triazolo[4,5‐b]pyridine on silver sols
Authors: Pergolese Barbara , Bigotto Adriano
Published: August 2002

The surface‐enhanced Raman (SER) spectra of 1H‐1,2,3‐triazolo[4,5‐b]pyridine adsorbed on silver hydrosols were recorded in the region 3500–100 cm−1. From the comparison of the SER and normal Raman spectra of 1H‐1,2,3‐triazolo[4,5‐b]pyridine both in the pure form and dissolved in alkaline solution, it can be deduced that the substance is dissociatively adsorbed on metal surface. In order to interpret the SER spectra, ab initio RHF calculations with a 6–31+G** basis set were performed to obtain the wavenumbers of the vibrational modes of the substance in the anionic form. Considering the relative enhancements of the Raman bands, on the basis of the description of normal modes given by the potential energy distribution it can be concluded that it interacts with silver sol essentially via the lone pairs of the nitrogen atoms, of both the pyridine and triazole rings, the ring π‐system playing a minor role, with a tilted orientation of the molecular plane with respect to the silver surface. Copyright © 2001 John Wiley & Sons, Ltd.
Resonance Raman spectra and transform analysis of anthracyclines and their complexes with DNA
Authors: Smulevich Giulietta , Mantini Anna R. , Feis Alessandro , Marzocchi Mario P.
Published: August 2002

The absorption, second‐derivative and resonance Raman spectra of some anthracyclines, namely idarubicin, epirubicin and 11‐deoxycarminomycin in H2O and D2O solutions, and their complexes with DNA in H2O solutions, were measured. Transform analysis that links resonance Raman band intensities to resonant absorption was applied to idarubicin, epirubicin and their complexes with DNA to obtain the Franck– Condon factors. The results allowed us to provide details on the nature of the resonance Raman active modes, the mechanism of their resonant enhancement and the chromophore–DNA interaction. In particular, an interpretation involving excited‐state charge transfer, associated in some cases with excited‐state proton transfer, is proposed. This helps to rationalize the observed variations of the intensities of Raman‐active modes of free anthracyclines in terms of variation of the transition moment direction. The intercalation of the chromophore among the DNA base pairs induces, via excitonic interactions, a change in both the magnitude and the direction of the transition moment of the chromophore. Copyright © 2001 John Wiley & Sons, Ltd.
Microspectrometric study of azobenzene chromophore orientations in a holographic diffraction grating inscribed on a p(HEMA‐co‐MMA) functionalized copolymer film
Authors: Labarthet F. Lagugné , Bruneel J. L. , Sourisseau C. , Huber M. R. , Börger V. , Menzel H.
Published: August 2002

An amorphous copolymer of methyl methacrylate (MMA, 60%) and hydroxyethyl methacrylate (HEMA, 40%), i.e. p(HEMA‐co‐MMA), was prepared by atom transfer radical polymerization (ATRP) and functionalized by complete esterification with the 2‐[4‐(4‐cyanophenylazo)phenoxy]acetic acid. An isotropic thin film (0.5 µm) of this copolymer with a 40% (molar fraction) azobenzene content was irradiated by interfering two orthogonal (±45°) linearly polarized laser beams (λ = 488 nm; irradiance = 1 W cm−2) and a permanent holographic diffraction grating was thus inscribed. AFM measurements revealed a nearly sinusoidal relief profile with a 2.5 µm period spacing and an amplitude of about 150 nm in the surface relief modulation (SRM). Using a confocal microspectrometric instrument we recorded various pre‐resonance enhanced polarized Raman spectra from a large grating area and obtained spatially resolved images of the Raman intensity variations, in order to gain new insight into the photoinduced orientation effects and the grating formation mechanisms. From analyses of the experimental data we extracted values of the second 〈P2〉 and fourth 〈P4〉 coefficients in the chromophore orientation functions at several positions of the SRM, in particular at the top and bottom regions: in general, we found that the weakly absorbing chromophores do not undergo strong orientation effects and, as expected, they keep an isotropic distribution at half‐slopes where the incident electric field was circularly polarized. Then, the corresponding normalized distribution functions were calculated using the information entropy theory. With respect to the sinusoidal relief surface, complex and broader distributions are found in the bottom and in the top regions, respectively, so that it appears that the mass transport phenomena have perturbed to some extent the primary photoinduced orientations. These results are compared with those we recently obtained using other highly birefringent copolymer samples. Copyright © 2001 John Wiley & Sons, Ltd.
Raman and infrared spectra, conformational stability from temperature‐dependent Fourier transform infrared spectra of xenon solutions, ab initio calculations and vibrational assignment of 4‐chlorobut‐1‐yne
Authors: Durig James R. , Drew Barry R. , Guirgis Gamil A.
Published: August 2002

The Raman spectra (3400–10 cm−1) of liquid and solid and the infrared spectra (3400–50 cm−1) of gaseous, xenon solution and solid 4‐chlorobut‐1‐yne, CH2ClCH2CCH, were recorded. These data indicate that the molecule exists in the anti (the C—Cl bond is trans to the CC bond) and the gauche conformations in the vapor and liquid and that both conformers persist in the solid with an indication that the gauche conformer may be more stable in this physical state. From a variable‐temperature infrared study of the xenon solution, the anti conformation has been determined to be more stable than the gauche form by 147 ± 10 cm−1 (1.76 ± 0.12 kJ mol−1). From these data it is estimated that 50% of the sample is in the gauche form at ambient temperature. The optimized geometries, conformation stabilities, harmonic force fields, Raman activities, depolarization ratios and infrared intensities were obtained from MP2/6–31G(d) ab initio calculations with full electron correlation. These quantities were compared with the corresponding experimental quantities when appropriate. Equilibrium geometries and energies for both conformers were obtained from ab initio MP2/6–311 + G(d, p) and MP2/6–311 + G(2d, 2p) calculations. Vibrational assignments for the 24 normal modes for both the anti and gauche conformers are proposed. These experimental and theoretical results are compared with the corresponding quantities for some similar molecules. Copyright © 2001 John Wiley & Sons, Ltd.
Two‐dimensional probing of ground‐state vibrational dynamics in porphyrin molecules by fs‐CARS
Authors: Heid M. , Schlücker S. , Schmitt U. , Chen T. , Schweitzer‐Stenner R. , Engel V. , Kiefer W.
Published: August 2002

We report on spectrally dispersed femtosecond time‐resolved coherent anti‐Stokes Raman scattering (CARS) for the investigation of the electronic ground‐state vibrational dynamics of porphyrin molecules in solution. The two‐dimensional experimental data obtained in our measurements provide a detailed mapping of the large number of molecular vibrations in these systems, excited by broadband ultrashort laser pulses, and make a thorough interpretation of the complex signal structure possible. In particular, an analysis of the data by applying Fourier transform methods to the time domain signal allows a clear identification of the excited porphyrin normal modes when compared with results on the mode structure from spectrally resolved (cw) spectroscopy. Altogether the method is capable of yielding detailed information on the dephasing behavior and on the relative spectral positions of the excited vibrations at the same time. Three porphyrin systems, dissolved in dichloromethane, were investigated: magnesium octaethylporphyrin, magnesium tetraphenylporphyrin and the free‐base porphyrin octaethylporphyrin. The measurements were performed in the spectral region of the ring vibrations of the porphyrin macrocycle. We also provide a discussion of the expected signals on a theoretical basis by deriving the CARS third‐order non‐linear polarization for these experiments. Copyright © 2001 John Wiley & Sons, Ltd.
Conformational study of AZT in aqueous solution and adsorbed on a silver surface by means of Raman spectroscopy
Authors: Rivas Laura , Sanchez‐Cortes Santiago , García‐Ramos José V.
Published: August 2002

The adsorption and conformation of the anti‐HIV drug AZT, and also thymine and 2′‐deoxythymidine, were studied on Ag colloids by surface‐enhanced Raman spectroscopy, showing that the conformational change induced by the adsorption on an Ag surface is similar to that induced by an alkaline pH, both related to deprotonation of the N‐3 atom leading to the C‐3′‐endo conformer. Copyright © 2002 John Wiley & Sons, Ltd.
Structural investigation of (Sr1−xCax)Bi2Ta2O9 ceramics
Authors: Das Rasmi R. , Pérez W. , Katiyar Ram S. , Bhalla A. S.
Published: August 2002

(Sr1−xCax)Bi2Ta2O9 bismuth‐layered compounds with composition x = 0, 0.2, 0.4, 0.6. 0.8 and 1.0 were synthesized by the conventional solid‐state route. Phase formation and structural evaluation of both calcined powders and sintered pellets were investigated using x‐ray diffraction and micro‐Raman spectroscopy. The decrease in the lattice parameters confirms the substitution of Sr by Ca with smaller ionic radii. The increase in orthorhombic distortion (b/a) with Ca content in SrBi2Ta2O9 (SBT) is attributed to the increase in lattice mismatch between TaO2 and SrO planes in the perovskite unit cell of SrTa2O7. The wavenumber of the lowest Raman modes increased with increase in mole fraction of Ca, establishing that the lower mass of Ca is indicative of an increase in the phase transition temperature (Tc) in comparison with the Tc of SrBi2Ta2O9. The decrease in intensity of the Raman lines and the increase in full width at half‐maximum of the Ta–O stretching mode, up to a 40% Ca content in SBT, might be due to a decrease in orthorhombic distortion of the unit cells. Copyright © 2002 John Wiley & Sons, Ltd.
Time‐resolved in situ Raman spectroscopy of working catalysts: sulfated and tungstated zirconia
Authors: Kuba S. , Knözinger H.
Published: August 2002

The spectra of time‐dependent in situ Raman experiments on sulfated and tungstated zirconia catalysts during the isomerization reaction of n‐pentane are presented and discussed. A purpose‐made in situ Raman cell which was used for this application is described. The choice of appropriate experimental parameters, namely laser power and laser wavelength, is discussed. During the experiments the activity and selectivity of the catalysts were determined simultaneously by on‐line gas chromatography. The sulfated zirconia catalyst shows structural changes in the sulfate region during the reaction. One of two different types of initially present sulfate species is eroded during the reaction, presumably due to a reduction to H2S. The activity shows a typical induction period followed by a fast deactivation. No coke formation is observed. Since fast deactivation occurs, coke formation cannot be the only reason for the deactivation of the catalyst. The tungstated catalyst shows strong darkening after initiation of the reaction with increasing time‐on‐stream (TOS). This leads to the disappearance of the catalyst bands. However, coke formation indicated by a broad band at 1590 cm−1 can be observed. Since darkening has a strong effect on Raman intensities, the time evolution of the observed bands is not obtained correctly. We propose a new method to correct for the effect of the darkening. The change of the diffuse reflectance of the catalyst is determined by the variation of the intensity of laser plasma lines. Based on an approximate equation proposed by Waters which correlates the Raman intensities and the diffuse reflectance of a sample, a correction factor for the spectra is obtained. After the intensity correction the spectra indicate that most of the coke is formed in the first few minutes of the reaction followed by a constant formation rate with TOS. Copyright © 2002 John Wiley & Sons, Ltd.
Competition between adsorption and complexation on silver as monitored by surface‐enhanced Raman scattering
Authors: Pessôa Mônica M. B. , Temperini Marcia L. A.
Published: August 2002

Surface‐enhanced Raman scattering (SERS) spectra of 2‐formylpyridine‐4′, 4′‐dimethyl thiosemicarbazone (DMePATS2) on a silver electrode in acetonitrile electrolytic solution were obtained. The effect of Mg(ClO4)2 on the DMePATS2 adsorption process was investigated. The results show that the configuration of adsorbed DMePATS2 on the silver electrode depends on the applied potential. For negative potentials, the predominant configuration on the surface is E whereas for positive potentials there is almost only the Z isomer. In the presence of Mg2+ only the (Z)‐DMePATS2 isomer was observed at any potential, which is explained by the formation of an Mg2+–(E)‐DMePATS2 complex in solution. The formation of this complex is also used to explain the decrease in the Raman intensity of the adsorbed species in the time evolution experiment. A comparison is made between the SERS results for DMePATS2 and PATS4 (4‐formylpyridine thiosemicarbazone). The SERS spectra of PATS4 in the presence of Mg2+ indicate the formation of an Mg2+–PATS4 complex on the surface. Copyright © 2002 John Wiley & Sons, Ltd.
Ab initioanalysis of Raman trace scattering intensities in alkenes and silanes
Authors: Lupinetti Concetta , Gough Kathleen M.
Published: August 2002

Molecular polarizabilities and derivatives with respect to CC, CH, SiSi and SIH stretching modes were obtained fromab initiomolecular orbital calculations at the HF/6–311G (3df,3pd) level for 14 molecules: ethene, cyclopropene, cyclobutadiene, cyclopentadiene,cis‐ andtrans‐butadiene,trans‐hexatriene, benzene, naphthalene and the silanes Si1 to Si5. Factors governing the trends in the intensities include conformation, chain length, location and orientation of a bond within the molecular framework. The results are compared with those from earlier studies on saturated alkanes and other work on conducting polymers. Copyright © 2002 John Wiley & Sons, Ltd.
Competitive strategy and strategic agendas
Authors: Grundy Tony
Published: August 2002

Competitive strategy has not evolved very significantly since Michael Porter's Competitive Advantage in 1985 but the analysis of strategic agendas helps to develop our understanding.

Strategic agendas shape the industry mind‐set and influence the impact of Porter's five competitive forces. This is manifest through the degree of psychological advantage which players in the industry have over each other.

Strategic agendas are found at a variety of levels and deeper ones need to be surfaced. The way strategic agendas impact on competitive strategy appears to be a very fruitful area for future research.
Regenerating a business's strategy: a method to release profits and build strength
Authors: Jeffery Ellis R.
Published: August 2002

Regenerating a business's strategy by conceiving strategic change helps leaders achieve higher and more sustainable financial performance.

Recent shifts in the world economy and new technology have put pressure on many businesses. Cost cutting and clever pricing cannot solve these problems alone because they require systemic attention and qualitative change.

Enterprise architectures seldom deliver expected profits. Standard solutions often reduce the competitive distinctions that sustain prices long run. By addressing the business holistically in full context, this method builds a strategic solution that increases profitability.

This article shows managers how to examine the intrinsic value of their business strategy and then build a more valuable strategy that can be sustained into the future. Conventional and contemporary thinking are combined into a method that managers can use to improve or regenerate a strategy for their organization.

Several checklists and frameworks are provided together with competitive insights on defining, evaluating and conceiving strategic change. These guidelines enable all members of a management team to contribute significantly to strengthening their business.

Copyright © 2001 John Wiley & Sons, Ltd.
Guest Editorial: From routine recipes to deep strategic thinking: strategy making as an intellectual challenge
Authors: Franklin Peter
Published: August 2002

The basic idea behind this editorial is that the routine recipes used by managers in the strategy process dull the intellectual palate and worse, divert attention from the principal strategic issue of business—namely, creating the future. To create the future requires three main ingredients:

A creative act. An activity or series of activities where imagination, innovation and creation cause people to (want to) do something different or do the same thing significantly differently.

An obsessive preoccupation with the future. An ability and inclination to look to the future rather than to the present or the past: an ability to be able to read the future (or a range of alternative futures), to feel the future, live the future and describe the future in ways which enable others to share and see the future with you.

Involvement, energy and passion. Organization‐wide commitment to the images of the future and understanding by individuals and teams, of their contributions to the shared imagined future.

Copyright © 2001 John Wiley & Sons, Ltd.
Optimisation of the Amido Black assay for determination of the protein content of grape juices and wines
Authors: Weiss Kathryn C , Bisson Linda F
Published: August 2002

While the heat/chill stability of white wines cannot be predicted from the total protein concentration, this information is useful in assessing the effectiveness of fining treatments. We have adapted the Amido Black assay for use in grape juice and wine. The response of bovine serum albumin (BSA) was similar in water, model wine and model juice. The linear range of the assay (<100 mg l−1) extends beyond protein concentrations typically found in grape juices and wines. The limit of quantification was 11.1 mg l−1 for BSA in model wine and 7.6 mg l−1 in model juice, while the limit of detection was found to be less than 3 mg l−1 in either solution. In contrast to other methods of protein determination, this assay is not affected by common wine phenolic and pectic compounds or by glutathione. The mean response of BSA was similar in model juice and red and white grape juices. The mean response of BSA in red wine was lower than in white wine and model wine (p < 0.001), and there was considerable variation in response among wines. Protein concentrations determined using this method were reproducible (CV < 10%). This optimised assay can be used to monitor protein levels in grape juices and wines.

© 2001 Society of Chemical Industry
Elevation of carotenoids in tomato by genetic manipulation
Authors: Fraser Paul D , Römer Susanne , Kiano Joy W , Shipton Cathie A , Mills Philippa B , Drake Rachel , Schuch Wolfgang , Bramley Peter M
Published: August 2002

Transgenic tomato lines expressing either the Erwinia uredovora phytoene synthase (crtB) or phytoene desaturase (crtI) gene have been produced using the polygalacturonase (PG) or CaMV 35S promoter respectively. Over three generations, tomato fruits expressing the additional phytoene synthase showed increased total carotenoids approaching twofold. Ripe tomato fruits expressing crtI showed significant increases in β‐carotene (threefold) but a reduction in the total carotenoid content (twofold). The contents of other biosynthetically related isoprenoids, including tocopherols (vitamin E), vitamin K, ubiquinones and plastoquinones, were not altered by manipulations to the carotenoid pathway. Detailed biochemical analysis indicates that both enzymes are targeted to the correct location and reside in active states. Increases in enzyme activity and the levels of carotenoid end‐products do not correlate. The data suggest that enhancement of carotenoids can be achieved by metabolic engineering of the pathway, but intrinsic regulatory mechanisms such as feedback inhibition and metabolite channelling may limit the potential shown by the increased enzyme activities.

© 2001 Society of Chemical Industry