bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrafast chemical interface scattering as an additional decay channel for nascent nonthermal electrons in small metal nanoparticles
Authors: Bauer Christophe , Abid Jean-Pierre , Fermin David , Girault Hubert H.
Published: April 2004

The use of 4.2 nm gold nanoparticles wrapped in an adsorbates shell and embedded in a TiO2 metal oxide matrix gives the opportunity to investigate ultrafast electron–electron scattering dynamics in combination with electronic surface phenomena via the surface plasmon lifetimes. These gold nanoparticles (NPs) exhibit a large nonclassical broadening of the surface plasmon band, which is attributed to a chemical interface damping. The acceleration of the loss of surface plasmon phase coherence indicates that the energy and the momentum of the collective electrons can be dissipated into electronic affinity levels of adsorbates. As a result of the preparation process, gold NPs are wrapped in a shell of sulfate compounds that gives rise to a large density of interfacial molecules confined between Au and TiO2, as revealed by Fourier-transform–infrared spectroscopy. A detailed analysis of the transient absorption spectra obtained by broadband femtosecond transient absorption spectroscopy allows separating electron–electron and electron–phonon interaction. Internal thermalization times (electron–electron scattering) are determined by probing the decay of nascent nonthermal electrons (NNEs) and the build-up of the Fermi–Dirac electron distribution, giving time constants of 540 to 760 fs at 0.42 and 0.34 eV from the Fermi level, respectively. Comparison with literature data reveals that lifetimes of NNEs measured for these small gold NPs are more than four times longer than for silver NPs with similar sizes. The surprisingly long internal thermalization time is attributed to an additional decay mechanism (besides the classical e–e scattering) for the energy loss of NNEs, identified as the ultrafast chemical interface scattering process. NNEs experience an inelastic resonant scattering process into unoccupied electronic states of adsorbates, that directly act as an efficient heat bath, via the excitation of molecular vibrational modes. The two-temperature model is no longer valid for this system because of (i) the temporal overlap between the internal and external thermalization process is very important; (ii) a part of the photonic energy is directly transferred toward the adsorbates (not among “cold” conduction band electrons). These findings have important consequence for femtochemistry on metal surfaces since they show that reactions can be initiated by nascent nonthermal electrons (as photoexcited, out of a Fermi–Dirac distribution) besides of the hot electron gas.
Interactive Web‐based programs for teaching nutrition
Authors: Wise A.
Published: April 2004

This paper describes four simulations of functions found in a commercial dietary analysis program that are designed to be used in education. These include FitDiets, which illustrates the principle of energy balance and “healthiness” of diets, and programs that present a nutritional quiz, a food label and information on dietetic products.
The evaluation of private prison design and construction submissions in Australia: prison operator responses
Authors: Consoli Giustina G.S.
Published: April 2004

A number of Australian states have employed private correctional companies to both manage, and design and construct their own facilities. Such projects have employed alternative delivery methods from what had been traditionally procured state facilities. The study highlights private prison operators' responses to the evaluation of their Request for Proposal by state governments. The findings reveal that although the evaluation of tender bids by the participating state governments was appropriate, various problems were encountered with the evaluation methodology employed to assess and award tenders. The study shows that the areas of concern include the: suitability and reliability of the evaluation methods; reactions to the bid outcomes; appropriateness of the debriefing sessions. The study shows that operators would prefer fundamental changes to the evaluation methodologies of the design and construction component of the private prison request for proposal evaluation.
International ethical dilemmas confronting Australian managers
Authors: Pedigo Kerry , Marshall Verena
Published: April 2004

Globalisation has seen diverse cultures becoming increasingly entwined and interdependent as business organisations operate in a borderless world. When organisations operate internationally they often find that countries differ in what is considered wrong or right. The objectives of the research were to identify cross‐cultural ethical dilemmas confronting Australian managers, and explore the strategies they utilise in dealing with those dilemmas in their international operations. The study raises the questions of whose ethics should be applied, and whether a set of universal ethical norms should be or can be developed. The discussion emanating from such questions also raises important issues for the training and ongoing management of employees undertaking business in the international environment. A total of 70 Australian managers from the mining, textile and information technology industries participated in this research, representing a cross‐section of Australian industry groups from the primary, secondary and tertiary sectors undertaking business in the international arena. The research utilised a conceptual framework that emerged from the moral philosophies represented in the international business arena Thr research utilised a conceptual framework that emerged from the moral philosophies represented in the international business arena, namely ethical relativism (Bowie 1996; Kohls & Buller 1994; Bowie & Duska 1990; Dobson 1990) imperialism (Gopalkrishnan 2001; Donaldson 1996b; De George 1993) and universalism (Beauchamp & Bowie 2001; Donaldson 1996b).
Modern warfare: no foresight without foreboding
Authors: Richardson Jacques
Published: April 2004

Military planning has various authors. The kings and emperors of old decided on whom to make war, where and when, with what, and for how long. The British Empire was built on economic push and domination abroad via a strong fleet. When Prussia united Germany in the nineteenth century, the planning task became that of the army's general staff. After Marxism‐Leninism gripped Russia in the twentieth century, plans and strategy emerged from the fountain‐head of the Central Committee of the Communist Party, but were entrusted to the generals for execution. In twenty‐first century USA there is a formalized structure for defence projection, yet parties outside the government may have an unusual voice in military planning.
The globalisation of knowledge: why trees become networks
Authors: Caraça João
Published: April 2004

Knowledge and the languages devised for its expression and circulation within communities evolve and drift with the times. The emergence of a new paradigm for technology, economy and society, based on information and knowledge, naturally brings along the need to rearrange and rethink our perception of how the diverse fields and disciplines are organised and classified, how they communicate and interact. A descriptive understanding of the realm of knowledge (as an “archipelago”) is discussed, enhancing its reticular character and its operation as a network that does not postulate any common origin or hierarchy. This metaphor is better adapted to map knowledge in a world of intensive communication and networking processes.
Dynamic and hierarchical classification of Web pages
Authors: Choi Ben , Peng Xiaogang
Published: April 2004

Automatic classification of Web pages is an effective way to organise the vast amount of information and to assist in retrieving relevant information from the Internet. Although many automatic classification systems have been proposed, most of them ignore the conflict between the fixed number of categories and the growing number of Web pages being added into the systems. They also require searching through all existing categories to make any classification. This article proposes a dynamic and hierarchical classification system that is capable of adding new categories as required, organising the Web pages into a tree structure, and classifying Web pages by searching through only one path of the tree. The proposed single‐path search technique reduces the search complexity from θ(n) to θ(log(n)). Test results show that the system improves the accuracy of classification by 6 percent in comparison to related systems. The dynamic‐category expansion technique also achieves satisfying results for adding new categories into the system as required.
Determination of deoxynivalenol and nivalenol chemotypes of Fusarium culmorum isolates from England and Wales by PCR assay
Authors: Jennings P. , Coates M. E. , Turner J. A. , Chandler E. A. , Nicholson P.
Published: April 2004

Functioning Tri13 and Tri7 genes are required for the production of nivalenol and 4‐acetyl nivalenol, respectively, in Fusarium species producing type B trichothecenes. Mutations have been identified in isolates which are able to produce deoxynivalenol (DON) but unable to convert this to nivalenol (NIV). In such isolates of Fusarium culmorum, the Tri7 gene is deleted entirely. PCR assays specific for functional and nonfunctional/deleted versions of Tri7 and Tri13 were used to determine the ability of 153 single spore isolates of F. culmorum to produce the 8‐ketotrichothecenes deoxynivalenol and nivalenol. The isolates were collected from 76 different locations across England and Wales between 1994 and 2002. Four isolates were also obtained from one field in Scotland. Both DON and NIV chemotypes of F. culmorum were identified, with DON chemotypes predominating overall. In addition, all DON chemotypes were shown to produce 3‐acetyl DON using primer sets developed to Tri3. From fields where more than one F. culmorum isolate was obtained, isolates were not exclusively of a single chemotype. Differences in the distribution of DON and NIV chemotypes were identified, with a greater proportion of NIV chemotypes present in the south and west of England and Wales, whereas a greater proportion of DON chemotypes were found in the north and east of England. Seasonal differences in the ratio of DON:NIV chemotypes were indicated. However, these were related to seasonal variation in the distribution of F. culmorum.
Major active faults determine the location of the Tongonan geothermal field: Evidence provided by rock alteration and stable isotope geochemistry
Authors: Scott Graeme L.
Published: April 2004

Abstract  The influence of major active faults on rock alteration and stable isotope geochemistry is described for the Tongonan geothermal field, Leyte, the Philippines. In the Pliocene, acid alteration with characteristic iron enrichment (3 g/100 g) and calcium depletion (2 g/100 g) occurred along a Riedel shear fault in the Malitbog sector, and initial minor acid alteration also occurred along a similar shear in the Mahiao sector. Later, sodium metasomatism (5 g/100 g) coincided with the highest aquifer chloride (10 000 mg/kg) as a result of dissociation of saline magmatic fluids discharging through the reservoir rocks in the Upper Mahiao. The incursion of magmatic fluids (possibly δD 35‰, δ18O +7‰) set up a vigorous convection cell of meteoric water, which focused around low‐angle (L) shears centered in the Sambaloran sector. Meteoric water (δD −35 to −40‰, δ18O −6 ± 1‰) depleted the reservoir in silica (6 g/100 g) and potassium (1–2 g/100 g). It also completely exchanged oxygen isotopes rapidly (within months) at high temperatures (300–400°C), and now does so continuously with fractured isotopically fresh or incompletely altered rock at small scales (centimeters or less) exposed by a 2 cm/year creep around the L shears to form a new component called geothermal water. Geothermal water mixes with meteoric water at lower temperatures (<300°C) to create the characteristic shift in δ18O of 6‰ at near constant δD (−35 ± 5‰). The 10‰ variation in δD is due to groundwater recharge derived from rain falling on steep terrain (5‰) and to enrichment of deuterium in boiling saline solutions (5‰); it is not due to two‐component mixing of meteoric with magmatic water. The low (∼1) isotopic water/rock (W/R) ratios calculated from oxygen isotopes in previously published reports are meaningless, because the water contains four components (predominantly geothermal and meteoric water; <10% magmatic and rock water). W/R ratios of up to 1500 calculated from spring and rock chemistry are more realistic and, with a flow rate of approximately 50 L/s through a 30 km3 reservoir, can account for the estimated 3 My age of the system.
Family Consequences of Refugee Trauma
Authors: Weine Stevan , Muzurovic Nerina , Kulauzovic Yasmina , Besic Sanela , Lezic Alma , Mujagic Aida , Muzurovic Jasmina , Spahovic Dzemila , Feetham Suzanne , Ware Norma , Knafl Kathleen , Pavkovic Ivan
Published: April 2004

Objective:  To construct a model on the consequences of political violence for refugee families based upon a qualitative investigation.

Methods:  This study used a grounded‐theory approach to analyze qualitative evidence from the CAFES multi‐family support and education groups with Bosnian refugee families in Chicago. Textual coding and analysis was conducted using ATLAS/ti for Windows.

Results:  A grounded‐theory model of Family Consequences of Refugee Trauma (FAMCORT) was constructed that describes Displaced Families of War across four realms of family life: (1) changes in family roles and obligations, (2) changes in family memories and communications, (3) changes in family relationships with other family members; and (4) changes in family connections with the ethnic community and nation state. In each realm, the model also specifies family strategies, called Families Rebuilding Lives, for managing those consequences.

Conclusions:  Political violence leads to changes in multiple dimensions of family life and also to strategies for managing those changes. Qualitative family research is useful in better understanding refugee families and in helping them through family‐oriented mental health services.
Activation of Adenoviral Gene Expression by Protein IX Is Not Required for Efficient Virus Replication
Authors: Sargent Kathy L. , Meulenbroek Robert A. , Parks Robin J.
Published: April 2004

The adenovirus (Ad) protein IX (pIX) is a minor component of the Ad capsid and is in part responsible for virion stability; virions lacking pIX are heat labile and lose their infectivity if the DNA content is greater than ∼35 kb. More recently, pIX has been identified as a transcriptional activator and, in transient-transfection assays, was shown to enhance expression from the E1A, E4, and major late Ad promoters by as much as 70-fold. In this study, we examined the role of pIX's ability to activate transcription during Ad replication. In transient-transfection assays, pIX had a minimal effect on expression from the E1A promoter, increasing expression by only 1.4-fold. We used helper-dependent Ad vectors, which had all Ad protein coding sequences deleted with the exception of E1A and which had capsids that either contained or lacked pIX, to show that pIX derived from decapsidation of the infecting virion does not influence expression of E1A. Similarly, expression of pIX from the Ad genome did not alter the expression levels of E1A. Viruses that had pIX deleted showed a threefold reduction in virus yield and expression of late genes compared to those of a similar virus which encoded pIX. This phenotype could not be rescued by growing the virus in cells which constitutively express pIX. Our results indicate that, although pIX can affect transcription from a variety of viral promoters, it does not appear to play a significant role in activation of Ad promoters during normal Ad replication.
Differential Cell Killing by Lymphomagenic Murine Leukemia Viruses Occurs Independently of p53 Activation and Mitochondrial Damage
Authors: Nanua Suparna , Yoshimura Fayth K.
Published: April 2004

Upon inoculation into AKR mice, mink cell focus-forming murine leukemia virus (MCF MLV) accelerates thymic lymphoma formation. During the preleukemic phase of disease, we observed the induction of apoptosis in thymic lymphocytes. A similar induction of apoptosis was observed for cultured mink epithelial cells after MCF13 MLV infection. In this study, the relevance of viral pathogenicity to cell killing was determined by testing the susceptibility of various cell types from different species to lymphomagenic MLVs. We observed that the cytopathic effect of lymphomagenic MLVs was restricted to mink cells. Southern blot analysis of MLV-infected cells revealed an accumulation of the linear form of unintegrated viral DNA, particularly in mink cells after MCF13 MLV infection. Thus, a strong correlation was observed between viral superinfection, which results in the accumulation of high levels of unintegrated viral DNA, and cell killing. Immunoblot analysis for MCF13 MLV-infected mink epithelial cells did not show a significant change in total p53 levels or its phosphorylated form at Ser-15 compared with that in mock-treated cells. Moreover, a time course analysis for mink epithelial cells infected with MCF13 MLV did not reveal mitochondrial depolarization or a significant change in Bax levels. These results demonstrate that MCF13 MLV induces apoptosis preferentially in cells in which superinfection occurs, and the mechanism involved is independent of p53 activation and mitochondrial damage.
Susceptibility of Cell Populations to Transduction by Retroviral Vectors
Authors: Wotherspoon Simon , Dolnikov Alla , Symonds Geoff , Nordon Robert
Published: April 2004

Retroviral transduction efficiency is related to the multiplicity of infection and the physiological state of the target cells. It is generally not known what proportion of a cell population is susceptible to transduction. We used coinfection with two retroviral vectors containing the marker genes for green fluorescent protein and the truncated human nerve growth factor receptor. In the CD34+cell line TF-1 or human primary CD34+hematopoietic progenitor cells, it was found that cells transduced with one vector had a better than random chance of transduction by the other vector. A probability model was developed to estimate target cell susceptibility; susceptibility was calculated as the product of the proportions of transgene-positive cells divided by the proportion of double-positive cells. By using this relationship, it was found that susceptibility was related to the target cell type and culture conditions but not the retroviral titer or the retroviral packaging envelope protein used in this study. Cotransduction with two vectors is a relatively simple procedure that provides a means to assess the maximum transduction level possible in a given cell population.
Cellular Repressor Inhibits Human Cytomegalovirus Transcription from the UL127 Promoter
Authors: Lashmit Philip E. , Lundquist Christopher A. , Meier Jeffery L. , Stinski Mark F.
Published: April 2004

The region of the human cytomegalovirus (HCMV) genome between the UL127 promoter and the major immediate-early (MIE) enhancer is referred to as the unique region. The role of this region during a viral infection is not known. In wild-type HCMV-infected permissive fibroblasts, there is no transcription from the UL127 promoter at any time during productive infection. Our investigators previously reported that the region upstream of the UL127 TATA box repressed expression from the UL127 promoter (C. A. Lundquist et al., J. Virol. 73:9039-9052, 1999). The region was reported to contain functional NF1 DNA binding sites (L. Hennighausen and B. Fleckenstein, EMBO J. 5:1367-1371, 1986). Sequence analysis of this region detected additional consensus binding sites for three transcriptional regulatory proteins, FoxA (HNF-3), suppressor of Hairy wing, and CAAT displacement protein. The
cis
-acting elements in the unique region prevented activation of the early UL127 promoter by the HCMV MIE proteins. In contrast, deletion of the region permitted very high activation of the UL127 promoter by the viral MIE proteins. Mutation of the NF1 sites had no effect on the basal activity of the promoter. To determine the role of the other sites in the context of the viral genome, recombinant viruses were generated in which each putative repressor site was mutated and the effect on the UL127 promoter was analyzed. Mutation of the putative Fox-like site resulted in a significant increase in expression from the viral early UL127 promoter. Insertion of wild-type Fox-like sites between the HCMV immediate-early (IE) US3 TATA box and the upstream NF-κB-responsive enhancer (R2) also significantly decreased gene expression, but mutated Fox-like sites did not. The wild-type Fox-like site inhibits activation of a viral IE enhancer-containing promoter. Cellular protein, which is present in uninfected or infected permissive cell nuclear extracts, binds to the wild-type Fox-like site but not to mutated sites. Reasons for repression of UL127 gene transcription during productive infection are discussed.
Mutated Form of the Newcastle Disease Virus Hemagglutinin-Neuraminidase Interacts with the Homologous Fusion Protein despite Deficiencies in both Receptor Recognition and Fusion Promotion
Authors: Li Jianrong , Quinlan Edward , Mirza Anne , Iorio Ronald M.
Published: April 2004

The Newcastle disease virus (NDV) hemagglutinin-neuraminidase (HN) protein mediates attachment to cellular receptors. The fusion (F) protein promotes viral entry and spread. However, fusion is dependent on a virus-specific interaction between the two proteins that can be detected at the cell surface by a coimmunoprecipitation assay. A point mutation of I175E in the neuraminidase (NA) active site converts the HN of the Australia-Victoria isolate of the virus to a form that can interact with the F protein despite negligible receptor recognition and fusion-promoting activities. Thus, I175E-HN could represent a fusion intermediate in which HN and F are associated and primed for the promotion of fusion. Both the attachment and fusion-promoting activities of this mutant HN protein can be rescued either by NA activity contributed by another HN protein or by a set of four substitutions at the dimer interface. These substitutions were identified by the evaluation of chimeras composed of segments from HN proteins derived from two different NDV strains. These findings suggest that the I175E substitution converts HN to an F-interactive form, but it is one for which receptor binding is still required for fusion promotion. The data also indicate that the integrity of the HN dimer interface is critical to its receptor recognition activity.
Nef Binds p6* in GagPol during Replication of Human Immunodeficiency Virus Type 1
Authors: Costa Luciana J. , Zheng Yong-Hui , Sabotic Jerica , Mak Johnson , Fackler Oliver T. , Peterlin B. Matija
Published: April 2004

The atypical Nef protein (NefF12) from human immunodeficiency virus type 1 strain F12 (HIV-1
F12
) interferes with virion production and infectivity via a mysterious mechanism. The correlation of these effects with the unusual perinuclear subcellular localization of NefF12 suggested that the wild-type Nef protein could bind to assembly intermediates in late stages of viral replication. To test this hypothesis, Nef from HIV-1
NL4-3
was fused to an endoplasmic reticulum (ER) retention signal (NefKKXX). This mutant NefKKXX protein recapitulated fully the effects of NefF12 on Gag processing and virion production, either alone or as a CD8 fusion protein. Importantly, the mutant NefKKXX protein also localized to the intermediate compartment, between the ER and the trans-Golgi network. Furthermore, Nef bound the GagPol polyprotein in vitro and in vivo. This binding mapped to the C-terminal flexible loop in Nef and the transframe p6* protein in GagPol. The significance of this interaction was demonstrated by a genetic assay in which the release of a mutant HIV-1 provirus lacking the PTAP motif in the late domain that no longer binds Tsg101 was rescued by a Nef.Tsg101 chimera. Importantly, this rescue as well as incorporation of Nef into HIV-1 virions correlated with the ability of Nef to interact with GagPol. Our data demonstrate that the retention of Nef in the intermediate compartment interferes with viral replication and suggest a new role for Nef in the production of HIV-1.
Characterization of Restrictions to Human Immunodeficiency Virus Type 1 Infection of Monocytes
Authors: Triques Karine , Stevenson Mario
Published: April 2004

Tissue macrophages are an important cellular reservoir for replication of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus. In vitro, the ability of macrophages to support viral replication is differentiation dependent in that precursor monocytes are refractory to infection. There is, however, no consensus as to the exact point at which infection is restricted in monocytes. We have revisited this issue and have compared the efficiencies of early HIV-1 replication events in monocytes and in differentiated macrophages. Although virus entry in monocytes was comparable to that in differentiated macrophages, synthesis of full-length viral cDNAs was very inefficient. Relative to differentiated macrophages, monocytes contained low levels of dTTP due to low thymidine phosphorylase activity. Exogenous addition ofd-thymidine increased dTTP levels to that in differentiated macrophages but did not correct the reverse transcription defect. These results point to a restriction in monocytes that is independent of reverse transcription precursors and suggest that differentiation-dependent cellular cofactors of reverse transcription are rate limiting in monocytes.
The contributions of Vietnamese learners of English to ELT methodology
Authors: Tomlinson Brian , Dat Bao
Published: April 2004

This article reports a survey of 300 intermediate-level EFL adult learners’ views about the instruction they receive and of 15 of their teachers at the National University of Vietnam in Ho Chi Minh City. Its main focus is on how learners can contribute to ELT methodology. The article reviews the literature on learner cultures and perceptions in language education and on the contributions that learners have made and could make to decisions about classroom methodology. It also reports the conduct and the results of the survey and uses this to discuss implications for L2 classrooms in Vietnam and elsewhere, and to suggest pedagogic interventions that could help to facilitate learner contributions and cater for learner needs and wants. The survey indicates that the teachers (as reported in other similar studies) were largely unaware of what their students felt and thought about the methodology of their courses, and that the learners would welcome changes to the culture of their classrooms.
Toy Story: Illustrating Gender Differences in a Motor Skills Task
Authors: Knight Jennifer L. , Hebl Michelle R. , Mendoza Miriam
Published: April 2004

To challenge students' stereotypes about gendered performance on motor skills tasks, we developed a classroom active learning demonstration. Four 3-person, same-gender teams received either a Barbie® doll or a Transformer®, and team members dressed the Barbie or manipulated the Transformer from a tank to a robot as quickly as possible, with each person responsible for 1 step of the process. As predicted, the teams were able to complete the assignment more quickly when given a gender stereotype-congruent task than an incongruent task. The demonstration served as a useful tool in helping students think critically about the origin and significance of gender differences, particularly in the area of manual dexterity. Quantitative data confirmed that students believed the demonstration was helpful and beneficial.
A Synthetic Neural Cell Adhesion Molecule Mimetic Peptide Promotes Synaptogenesis, Enhances Presynaptic Function, and Facilitates Memory Consolidation
Authors: Cambon Karine , Hansen Stine M. , Venero Cesar , Herrero A. Isabel , Skibo Galina , Berezin Vladimir , Bock Elisabeth , Sandi Carmen
Published: April 2004

The neural cell adhesion molecule (NCAM) plays a critical role in development and plasticity of the nervous system and is involved in the mechanisms of learning and memory. Here, we show that intracerebroventricular administration of the FG loop (FGL), a synthetic 15 amino acid peptide corresponding to the binding site of NCAM for the fibroblast growth factor receptor 1 (FGFR1), immediately after training rats in fear conditioning or water maze learning, induced a long-lasting improvement of memory. In primary cultures of hippocampal neurons, FGL enhanced the presynaptic function through activation of FGFR1 and promoted synapse formation. These results provide the first evidence for a memory-facilitating effect resulting from a treatment that mimics NCAM function. They suggest that increased efficacy of synaptic transmission and formation of new synapses probably mediate the cognition-enhancing properties displayed by the peptide.
Early Striatal Dendrite Deficits followed by Neuron Loss with Advanced Age in the Absence of Anterograde Cortical Brain-Derived Neurotrophic Factor
Authors: Baquet Zachary C. , Gorski Jessica A. , Jones Kevin R.
Published: April 2004

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, modulates neuronal survival, differentiation, and synaptic function. Reduced BDNF expression in the cortex caused by mutation of thehuntingtingene has been suggested to play a role in the striatal degeneration observed in Huntington's disease. BDNF expression rises dramatically in the cortex during the first few weeks of postnatal life in mice. Previously, it has been impossible to study the specific long-term effects of BDNF absence on CNS structures because of the early postnatal lethality ofBDNF-/-mice. Mice harboring a floxedBDNFgene were bred withEmx1IREScre/+mice to generateEmx-BDNFKOmice that lack cortical BDNF but are viable. AdultEmx-BDNFKOmice display a hindlimb clasping phenotype similar to that observed in mouse models of Huntington's disease. The striatum of postnatalEmx-BDNFKOmice was reduced in volume compared with controls, and the most abundant neuron type of the striatum, medium spiny neurons (MSNs), had shrunken cell somas, thinner dendrites, and fewer dendritic spines at 35 d of age. Although significant striatal neuron losses were not detected at 35 or 120 d postnatal, 35% of striatal neurons were missing inEmx-BDNFKOmice aged beyond 1 year. Thus, cortical BDNF, although not required for the generation or near-term survival of MSN, is necessary for normal striatal neuron dendrite morphology during the period when BDNF expression rises in the cortex. Furthermore, a long-termin vivorequirement for cortical BDNF in supporting the survival of MSNs is revealed.
Imaging of Muscarinic Acetylcholine Receptor Signaling in Hippocampal Neurons: Evidence for Phosphorylation-Dependent and -Independent Regulation by G-Protein-Coupled Receptor Kinases
Authors: Willets Jonathon M. , Nash Mark S. , Challiss R. A. John , Nahorski Stefan R.
Published: April 2004

We used the inositol 1,4,5-trisphosphate (IP3) biosensor, the pleckstrin homology (PH) domain of PLCδ1 (phospholipase C) tagged with enhanced green fluorescent protein (eGFP-PHPLCδ), to examine muscarinic acetylcholine (mACh) receptor regulation of phospholipase C/IP3signaling in intact single hippocampal neurons in “real time.” Initial experiments produced a pharmacological profile consistent with the presence of a predominant M1mACh receptor population coupled to the IP3response. To investigate M1mACh receptor regulation, neurons were stimulated with approximate EC50concentrations of the mACh receptor agonist methacholine before (R1) and after (R2) a short (60 sec) exposure to a high concentration of agonist. This resulted in a marked attenuation in the R2 relative to R1 response. Inhibition of endogenous GRK6 (G-protein-coupled receptor kinase) activity, by the introduction of catalytically inactiveK215RGRK6, partially reversed the attenuation of agonist-induced responsiveness, whereas overexpression of wild-type GRK6 increased receptor desensitization. Manipulation of endogenous GRK2 activity through introduction of either wild-type or catalytically inactive GRK2 (K220RGRK2) almost completely inhibited agonist-stimulated IP3production, implying a phosphorylation-independent regulation of M1mACh receptor signaling, most probably mediated by a GRK2 N-terminal RGS-like (regulator of G-protein signaling) domain interaction with GTP-bound Gαq/11. Together, our data suggest a role for both phosphorylation-dependent and -independent regulation of M1mACh receptors in hippocampal neurons.
Material Flow During Equal Channel Angular Pressing of Aluminum Containing Al8Fe2Si Precipitates
Authors: Korchef A. , Njah N. , Champion Y. , Guérin S. , Leroux C. , Masmoudi J. , Kolsi A.
Published: April 2004

99.1% aluminium containing Al8Fe2Si precipitates located at grain boundaries, was deformed by ECA pressing. Evolution of the plastic flow was evaluated from the spatial distribution of precipitates characterized by Optical Microscopy. The theoretical models of the deformation, based on simple shear, fit with the experimental results for the number of passes N=1 and 2. For further pressings, discrepancies are observed, indicating that more complex deformation processes may be operative.
Polymer Nanocomposites for Aerospace Applications: Fabrication
Authors: Njuguna J. , Pielichowski K.
Published: April 2004

Nanocomposite polymers have tremendous potential to enhance the performance of macromolecular materials used for composite matrices. Effective utilization of carbon nanotubes in composite applications depends strongly on the ability to homogeneously disperse them throughout the matrix without destroying their integrity. This work looks at the fabrication for montmorillonite, fullerenes and nanotubes polymer/nanocomposites tailored to fit aerospace needs. Further insight is also given on developments in nanofibers and nanotubes production for good load transfer on the composite systems.
Kontroversen in der Chemie: Was gilt als Beweis? – Zwei Studien zur Struktur von Molekülen
Authors: Labinger Jay A. , Weininger Steve J.
Published: April 2004

Hinterher ist man immer schlauer: Kontroversen zu charakterisieren, während sie im Gange sind, ist schwierig. Viel leichter ist dies, wie sich bei der Stereochemie und der Bindungslängenisomerie gezeigt hat, wenn alle Beweise vorliegen. Beide Beispiele belegen, wie wichtig es ist, alle experimentellen Ergebnisse zu berücksichtigen, bevor Schlüsse gezogen werden. Vor allem das zweite Beispiel zeigt, dass manche Beweise gleicher sind als andere – der Kristallstrukturuntersuchung galt in allen Phasen das größte Vertrauen.
Application of different kinetic models to analyze the reaction rates of liquid crystalline homopolyesters
Authors: Al‐Adwani H. , Bishara A. E. , Al‐Roomi Y. , Mathew J. , Shaban H. I.
Published: April 2004

Kinetics of homopolyesterification between methyl hydroquinone diacetate (MHQDA) and 1,4‐naphthalene dicarboxylic acid (1,4‐NDCA) in the melt were analyzed using three different rate models. The three different techniques used to evaluate the kinetic parameters for the homopolymerization reaction were as follows: simple second‐order textbook equation, a simple second‐order kinetic model, and Mathew's model. A simple second‐order reaction mechanism previously reported by Mathew et al. is found to summarize the catalyzed and uncatalyzed reactions between MHQDA and 1,4‐NDCA. Close comparison was obtained between the experimental and theoretical data by using the Mathew's model. Mathew's model was found to perfectly fit the experimental data. The kinetic analysis of the studied system reveals the implicit simplicity of complex systems. The percentage error for the fit was found to be <5% for the Mathew's model. These novel homopolymers were analyzed for their thermal properties by using a differential scanning calorimeter. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1118–1128, 2004
Probing the Proteolytic Stability of β‐Peptides Containing α‐Fluoro‐ and α‐Hydroxy‐β‐Amino Acids
Authors: Hook David F. , Gessier François , Noti Christian , Kast Peter , Seebach Dieter
Published: April 2004

One of the benefits of β‐peptides as potential candidates for biological applications is their stability against common peptidases. Attempts have been made to rationalize this stability by altering the electron availability of a given amide carbonyl bond through the introduction of polar substituents at the α‐position of a single β‐amino acid. Such β‐amino acids (β‐homoglycine, β‐homoalanine), containing one or two fluorine atoms or a hydroxy group in the α‐position, were prepared in enantiopure form. A versatile method for preparing these α‐fluoro‐β‐amino acids by the homologation of appropriate α‐amino acids and C‐OH→C‐F or CO→CF2 substitution with DAST, is described. Consequently, a series of β‐peptides possessing an electronically modified residue at the N terminus or embedded within the chain was synthesized, and their proteolytic stability was investigated against a selection of enzymes. All ten β‐peptides tested were resilient to proteolysis. Introducing a polar, sterically undemanding group, into the α‐position of β‐amino acids in a β‐peptide chain does not appear to facilitate localized or general enzymatic degradation.
Enzymatic Fluorination in Streptomyces cattleya Takes Place with an Inversion of Configuration Consistent with an SN2 Reaction Mechanism
Authors: Cadicamo Cosimo D. , Courtieu Jacques , Deng Hai , Meddour Abdelkrim , O'Hagan David
Published: April 2004

The stereochemical course of the recently isolated fluorination enzyme from Streptomyces cattleya has been evaluated. The enzyme mediates a reaction between the fluoride ion and S‐ adenosyl‐L‐methionine (SAM) to generate 5′‐fluoro‐5′‐deoxyadenosine (5′‐FDA). Preparation of (5′R)‐[5‐2H1]‐ATP generated (5′R)‐[5‐2H1]‐5′‐FDA in a coupled enzyme assay involving SAM synthase and the fluorinase. The stereochemical analysis of the product relied on 2H NMR analysis in a chiral liquid‐crystalline medium. It is concluded that the enzyme catalyses the fluorination with an inversion of configuration consistent with an SN2 reaction mechanism.
Experimental Measurement of Noncovalent Interactions Between Halogens and Aromatic Rings
Authors: Adams Harry , Cockroft Scott L. , Guardigli Claudio , Hunter Christopher A. , Lawson Kevin R. , Perkins Julie , Spey Sharon E. , Urch Christopher J. , Ford Rhonan
Published: April 2004

Chemical double mutant cycles have been used to quantify the interactions of halogens with the faces of aromatic rings in chloroform. The halogens are forced over the face of an aromatic ring by an array of hydrogen‐bonding interactions that lock the complexes in a single, well‐defined conformation. These interactions can also be engineered into the crystal structures of simpler model compounds, but experiments in solution show that the halogen–aromatic interactions observed in the solid state are all unfavourable, regardless of whether the aromatic rings contain electron‐withdrawing or electron‐donating substituents. The halogen–aromatic interactions are repulsive by 1–3 kJ mol−1. The interactions with fluorine are slightly less favourable than with chlorine and bromine.
The Role of Binding Constants in the Efficiency of Chiral Catalysts Immobilized by Electrostatic Interactions: The Case of Azabis(oxazoline)–Copper Complexes
Authors: Fraile José M. , García José I. , Herrerías Clara I. , Mayoral José A. , Reiser Oliver , Socuéllamos Antonio , Werner Heiko
Published: April 2004

As shown by theoretical calculations, azabis(oxazoline)–copper complexes are considerably more stable than the analogous bis(oxazoline)–copper complexes. This enhanced stability allows them to be efficiently immobilized by means of electrostatic interactions to different anionic supports, such as clays and nafion–silica nanocomposites, without the loss of a ligand, as is observed for bis(oxazolines). As a result, enantioselectivities of around 90 % ee are obtained in the cyclopropanation reaction between styrene and ethyl diazoacetate. Moreover, the solid catalyst is easily recoverable.
Optimiertes distributives Mischen mittels „chaotischer”︁ Multilamination
Authors: Schönfeld F. , Hardt S. , Hessel V. , Hofmann C.
Published: April 2004

No abstracts.
Mikrostrukturkomponenten für die Wasserstofferzeugung aus unterschiedlichen Kohlenwasserstoffen
Authors: Pfeifer P. , Bohn L. , Görke O. , Haas‐Santo K. , Schubert K.
Published: April 2004

No abstracts.
Baukastenkonzepte für die Mikroverfahrenstechnik: Das FAMOS‐System
Authors: Löbbecke S.
Published: April 2004

No abstracts.
Automatisierung in der Mikroreaktionstechnik: Das AuMμRes‐System
Authors: Löbbecke S. , Ferstl W. , Lohf A. , Steckenborn A. , Hassel J. , Häberl M. , Schmalz D. , Muntermann H. , Bayer T. , Kinzl M. , Leipprand I.
Published: April 2004

No abstracts.
Wärme‐ und Stofftransport in mikrofluidischen Mehrphasensystemen: Forschungsaktivitäten an der TU Darmstadt
Authors: Stephan P. , Hardt S.
Published: April 2004

No abstracts.
Nanoporöse Katalysatorschichten für Anwendungen im Mikroreaktor
Authors: Zapf R. , Hessel V.
Published: April 2004

No abstracts.
Mikroverfahrenstechnik – Perspektiven für die Umwelt
Authors: Hempel M.
Published: April 2004

No abstracts.
VDI‐Seminar „Mikroverfahrenstechnik – Eine intelligente Lösung für organische Synthesen und Mischprozesse”︁
Authors: Hessel V. , Schulz M.
Published: April 2004

No abstracts.
Chemical Synthesis in Micro Reactors
Authors: Watts P.
Published: April 2004

This article reviews the current applications of micro reactors in the field of combinatorial chemistry and discusses how the methodology could be applied to drug discovery. Liquid phase reactions have been used to illustrate the advantages of performing chemical reactions in micro reactors which illustrate that reactions can be performed very rapidly in high conversion to enable the preparation of combinatorial libraries of structurally related compounds.
Discovering New Water Soluble Catalysts for the Liquid/Liquid Isomerization of Allylic Alcohols Using Microdevices
Authors: de Bellefon C. , Abdallah R. , Ireland T.
Published: April 2004

No abstracts.
The radon transform: A new scheme for fast multidimensional NMR
Authors: Kupče Eriks , Freeman Ray
Published: April 2004

Multidimensional nuclear magnetic resonance (NMR) spectra are used widely for structure elucidation of molecules of biochemical interest, particularly proteins, but the existing methodology is severely hampered by the long duration of the measurement, often many days. Here, we show that the inverse Radon transform can be used to reconstruct such a spectrum from a small number of different plane projections. This “projection‐reconstruction” (PR) technique reduces the time required to perform a three‐dimensional experiment by an order of magnitude and four‐dimensional spectra by two orders of magnitude, greatly extending the scope of such investigations. We show the application of the inverse Radon transform to reconstruct the four‐dimensional NMR spectrum of the nuclease A inhibitor, a measurement completed in only 35 min. This new technique is expected to have wide implications for investigations of protein structure and dynamics, currently a very active field of research. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson 22A: 4–11, 2004.
Pathologic evaluation of radical cystectomy specimens
Authors: Herr Harry W. , Faulkner James R. , Grossman H. Barton , Crawford E. David
Published: April 2004

BACKGROUND

The authors evaluated the pathology of radical cystectomy and pelvic lymph node specimens from patients with bladder carcinoma who were enrolled in a cooperative group trial. Their objective was to determine whether current practices conform to suggested pathology practice guidelines for reporting on radical cystectomy and pelvic lymph node specimens.

METHODS

Overall, 268 patients underwent radical cystectomy with pelvic lymph node dissection over 11 years in a total of 109 diverse geographic locations and types of institutions. Institutions included 50 community hospitals, 36 academic hospitals, and 23 Veterans Administration (VA)/military hospitals, which evaluated 84, 137, and 47 patients, respectively. The quality of pathology examination was assessed based on the original pathology reports of specimens that were submitted according to published practice guidelines.

RESULTS

Among all types of institutions, pathologic evaluation of radical cystectomy specimens generally was complete for tumor histology, grade, size, location, pathologic stage, lymph node status, prostate involvement, and associated mucosal abnormalities, including ureters and urethra. Perivesical fat (soft tissue) margins were not recorded in 10% of specimens, and 18% of patients did not mention either the presence or the number of lymph nodes. These deficiencies were observed primarily at community and VA hospitals.

CONCLUSIONS

The overall quality of pathologic examination of radical cystectomy specimens is high. Better reporting of soft tissue margin status and pelvic lymph node counts is needed to achieve compliance with the standards published by evolving practice protocols. Standardized pathologic evaluation and reporting of radical cystectomy specimens will optimize important prognostic information and foster better communication between the pathologist, surgeon, and interested oncologists to benefit patients. Cancer 2004. © 2004 American Cancer Society.
Regioselective SN2 Opening of Vinylic Epoxides with Trialkylzincates and Trialkylaluminates
Authors: Equey Olivier , Vrancken Emmanuel , Alexakis Alexandre
Published: April 2004

The use of trialkylorganozincates and tetraalkylaluminates allows regioselective SN2 nucleophilic opening of vinylic epoxides. The reaction occurs with an anti‐substitution pattern and can be applied to a wide range of substrates. We also show that the solvent and the structure of the epoxide have an influence on the substitution products’ ratio. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Transgenic Cre expression mice for generation of erythroid‐specific gene alterations
Authors: Peterson Kenneth R. , Fedosyuk Halyna , Zelenchuk Lesya , Nakamoto Betty , Yannaki Evangelia , Stamatoyannopoulos George , Ciciotte Steven , Peters Luanne L. , Scott Linda M. , Papayannopoulou Thalia
Published: April 2004

Summary: Transgenic mice that express Cre recombinase in erythroid cell lineages were developed so that genes affecting erythropoiesis/hematopoiesis may be altered without necessarily affecting fetus viability. A micro‐LCR cassette‐β‐globin promoter‐Cre recombinase gene (μLCR‐βpr‐Cre) construct was synthesized and used to generate transgenic mice. Concurrently, we produced mice containing a μLCR‐loxP‐flanked β sickle gene (μLCR‐loxP‐βS‐loxP) construct. μLCR‐βpr‐Cre mice with intact transgenes in variable copy number were identified. Cre expression was assessed by RNAse protection and RT‐PCR. Cre function was ascertained by breeding to μLCR‐loxP‐βS‐loxP mice. We demonstrate that βS expression was not detected in the blood of bigenics, but the gene was present in nonerythroid cells. Thus, excision of the loxP‐flanked βS gene was restricted to erythroid cell lineages. genesis 39:1–9, 2004. © 2004 Wiley‐Liss, Inc.