bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic and analytical study on a low-pressure limit of diamond chemical vapor deposition in inductively coupled CO–CH4–H2 plasmas
Authors: Teii Kungen , Hori Masaru , Goto Toshio
Published: March 2004

The role of neutral radicals and charged ions in a low-pressure limit of plasma-enhanced chemical vapor deposition of diamond has been studied by plasma diagnostics and a kinetic rate analysis for radicals. The fluxes of atomic hydrogen (H), methyl radicals (CH3), and ionic species were determined by optical absorption spectroscopy and mass spectrometry. The ion-bombardment energy was estimated by measuring plasma potentials and ion energy distributions. The deposits were obtained on Si and diamond substrates with a mean ion energy of a few eV. At 10 mTorr, nanocrystalline diamond could be deposited on a diamond substrate, while not on a Si substrate, as confirmed by Raman spectroscopy. In this limiting condition, attempts were made to lower the pressure limit by increasing fluxes of carbonaceous species and/or reducing an ion-to-adatom flux ratio. It was found that low radical fluxes rather than a high ion-to-adatom flux ratio limited the nucleation. The calculated growth rates with the measured H and CH3 densities from a simplified growth model for a set of reactions of adsorbed H and CH3 were compared to the experimental ones, and then the creation of radical sites was likely to limit the growth. A transition from diamond to no diamond growth in the pressure limit of growth was demonstrated by comparing kinetic reaction rates for desorption and incorporation of adsorbed CH3. The results show how the nucleation and the growth are limited by radical fluxes and modified to a degree by dynamic effects of energetic ions.
Band gap energy and valence band splitting of p-CdIn2Te4 crystal by photocurrent spectroscopy
Authors: You S. H. , Hong K. J. , Jeong T. S. , Youn C. J. , Park J. S. , Shin D. C. , Moon J. D.
Published: March 2004

Single crystals of p-CdIn2Te4 were grown by the Bridgman method without a seed crystal. From photocurrent measurements, it was found that three peaks, A, B, and C, correspond to the intrinsic transition from the valence band states of Γ7(A), Γ6(B), and Γ7(C) to the conduction band state of Γ6, respectively. The crystal field splitting and the spin orbit splitting were found to be 0.2360 and 0.1119 eV, respectively. The temperature dependence of the CdIn2Te4 band gap energy was given by Eg(T)=Eg(0)−(9.43×10−3)T2/(2676+T). The Eg(0) was calculated to be 1.4750, 1.7110, and 1.8229 eV at the valence band states of Γ7(A), Γ6(B), and Γ7(C), respectively. The band gap energy of p-CdIn2Te4 at room temperature was determined to be 1.2023 eV.
Dynamic behavior of boron carbide
Authors: Vogler T. J. , Reinhart W. D. , Chhabildas L. C.
Published: March 2004

Boron carbide displays a rich response to dynamic compression that is not well understood. To address poorly understood aspects of behavior, including dynamic strength and the possibility of phase transformations, a series of plate impact experiments was performed that also included reshock and release configurations. Hugoniot data were obtained from the elastic limit (15–18 GPa) to 70 GPa and were found to agree reasonably well with the somewhat limited data in the literature. Using the Hugoniot data, as well as the reshock and release data, the possibility of the existence of one or more phase transitions was examined. There is tantalizing evidence, but at this time no phase transition can be conclusively demonstrated. However, the experimental data are consistent with a phase transition at a shock stress of about 40 GPa, though the volume change associated with it would have to be small. The reshock and release experiments also provide estimates of the shear stress and strength in the shocked state as well as a dynamic mean stress curve for the material. The material supports only a small shear stress in the shocked (Hugoniot) state, but it can support a much larger shear stress when loaded or unloaded from the shocked state. This strength in the shocked state is initially lower than the strength at the elastic limit but increases with pressure to about the same level. Also, the dynamic mean–stress curve estimated from reshock and release differs significantly from the hydrostate constructed from low-pressure data. Finally, a spatially resolved interferometer was used to directly measure spatial variations in particle velocity during the shock event. These spatially resolved measurements are consistent with previous work and suggest a nonuniform failure mode occurring in the material.
Oxygen lone-pair states near the valence band edge of aluminum oxide thin films
Authors: Zhao Z. W. , Tay B. K. , Sun Chang Q. , Ligatchev V.
Published: March 2004

Deep level transient spectroscopy and optical absorption spectroscopy measurement revealed three outstanding features of density-of-states (DOS) appeared above the valence band edge (Ev) of Al oxide thin films. The broad peak located at 0.39 eV above Ev disappears while the other two located at 1.0 and 1.3 eV shift in position and attenuate in intensity upon annealing at 200 °C. The latter two peaks are removed by annealing at temperature up to 400 °C. The observed midgap DOS feature dynamics is in accordance with the oxygen lone pair features as confirmed earlier with Raman spectroscopy in the low-frequency ranges [C. Q. Sun et al., J. Appl. Phys. 90, 2615 (2001)] and thermal desorption measurements of other oxide surfaces.
Continuum model for nanocolumn growth during oblique angle deposition
Authors: Main E. , Karabacak T. , Lu T. M.
Published: March 2004

A continuum equation for the shadowing growth of individual nanostructures by oblique angle deposition is proposed and numerically integrated. The radius R of rotationally symmetric columns is calculated as a function of height z. Before the radius R saturates at its final value Rsat, column shapes obey the power law R∼zp with the exponent value p∼0.37±0.02. The results are compared to those of an experimental study of Si columns grown on a template (p∼0.39±0.03), and on a flat surface (p∼0.32±0.01). The model additionally predicts that the saturated radius should depend on column separation d as Rsat∼d1.20±.01. This relation implies that the gap between the surfaces of adjacent columns can be optimized by altering the column separation.
Forward voltage drop degradation in diffused SiC p-i-n diodes
Authors: Soloviev S. , Cherednichenko D. , Gao Y. , Grekov A. , Ma Y. , Sudarshan T. S.
Published: March 2004

The time varying relationship between forward voltage drop and temperature in degrading diffused 4H–SiC p-i-n diodes was used to estimate the activation energy (0.34 eV) of the degradation process associated with the formation of stacking faults (SFs). A very strong peak appeared in the electroluminescence spectra at 427 nm and increased steadily in intensity as the forward voltage drop increased. The mismatch stresses, localized in the diffused doped region, are proposed to play a dominant role in the initial formation of SFs. Calculations were performed for the phonon pressure caused by nonradiative carrier recombination, which presumably is responsible for the development and motion of the SFs leading to the observed forward voltage degradation.
Experimental and theoretical study of magneto-inductive waves supported by one-dimensional arrays of “swiss rolls”
Authors: Wiltshire M. C. K. , Shamonina E. , Young I. R. , Solymar L.
Published: March 2004

The propagation of magneto-inductive waves in a one-dimensional array of “swiss roll” metamaterial has been studied. It was found that long-range interactions over the whole of the array must be included to describe the excitations accurately. Using the dispersion relations deduced from experimental data on pairs of elements, the coupling coefficients between all the elements in the array have been determined by matching the experimental and theoretical curves. The relative amplitudes and phases of the excitations on each element in a 31-member array have been measured and compared with the theoretical prediction based on the previously derived coupling coefficients. Excellent agreement between the predicted and measured behavior is found, provided that a full set of coupling coefficients is used.
Self-consistent calculations for n-type hexagonal SiC inversion layers
Authors: Pennington G. , Goldsman N.
Published: March 2004

Surface band structure calculations are performed for different orientations of hexagonal silicon carbide (nH-SiC). The 4H-SiC and 6H-SiC hexagonal polytypes are considered. The subband structure perpendicular to an oxide-SiC interface is determined self-consistently with the confining transverse potential. Investigations have been performed in the range of weak/strong inversion and high/low temperatures. The (011̄0), (112̄0), (033̄8), and (0001) surfaces are compared for both 4H-SiC and 6H-SiC. Each orientation is characterized based on its two-dimensional nature, its degree of anisotropy parallel to the oxide, and the spatial extent of mobile electrons from the oxide–semiconductor interface.
Optimized minimal inductance transmission line configuration for Z-pinch experiments
Authors: Hurricane O. A.
Published: March 2004

Successful dynamic Z-pinch experiments generally require good current delivery to the target load. Power flow losses through highly inductive transmission line configurations reduce the current available to the load. In this brief article, a variational calculus technique is used to determine the transmission line configuration that produces the least possible inductance and therefore the best possible current delivery for Z-pinch experiments.
Mediating the ‘National’ and the ‘Local’ in the Environmental Policy Process: A Case Study of the CPRE
Authors: Lowe Philip , Murdoch Jonathan
Published: March 2004

As environmental concerns press upon public policy so state agencies tend to enter into governmental ‘partnerships’ with environmental groups. On the one hand, these ‘partnerships’ allow the state to call upon forms of expertise held by the groups and to gain broad legitimacy for state policies. On the other hand, the development of policy partnerships enables environmental groups to influence policy formulation processes directly. However, it also means that such groups must ‘sell’ the agreed policy line to local members. Using the case study of the Council for the Protection of Rural England (CPRE), we investigate how environmental groups manage the relationship between national policymaking and local support. Through the investigation of three CPRE county branches we reveal an uneven geography of environmental governance and show how this geography affects the diffusion of environmental policy objectives. We argue that the implementation of environmental policies must be set within local economic, political, and social conditions as these conditions ensure considerable variation in modes of environmental governance.
Rural—Urban Differences in Privatization: Limits to the Competitive State
Authors: Warner Mildred , Hefetz Amir
Published: March 2004

Despite two decades of experience with privatization, US local government use of contracting in public service delivery remains relatively flat. Market approaches to public goods provision emphasize the competitive state, and attribute limited degree of privatization to bureaucratic resistance. Rural development theory emphasizes the uneven impact of market solutions in rural communities. Using national data on US local government service delivery from 1992 and 1997, we analyze differences in local government service-delivery patterns by metropolitan status. Discriminant analysis suggested that structural features of markets are more important than the managerial capacity of government leaders in explaining lower rates of privatization among rural governments. These structural constraints limit the applicability of competitive approaches to local government service delivery. Our results suggest that cooperation, as an alternative to privatization at the local level and as a source of redistributive aid at the state level, may provide a more equitable alternative for disadvantaged rural communities.
Interpretive Analysis as an Evaluative Tool: The Case of Mustard.UK.Com, a High-Growth Small Business Programme
Authors: Patton Dean , Marlow Susan , Ram Monder , Sanghera Kul
Published: March 2004

The authors suggest that a more interpretist analysis of policy design, development, and implementation that takes into account antecedent factors, context, reflective change, and user and advisor perception and expectations would make a significant contribution to the field of policy evaluation. This concept is considered further using a qualitative assessment of the West Midlands response, Mustard.UK.Com (Mustard), to the government's High Growth Start-Up scheme set out in the Department of Trade and Industry's Competitiveness White Paper in 1998. The assessment has three elements: first, an exploration of the extant literature to identify any relevant antecedent factors that may have informed or influenced the decisionmaking process when the West Midlands response was being developed; second, a review of the procedure by which the various parties involved in the implementation of Mustard created a framework within which a workable support programme could be delivered; third, the extent to which Mustard has been successful in meeting the objectives of those stakeholders involved in the programme is considered.
Demutualisation, Strategic Choice, and Social Responsibility
Authors: Marshall J Neill , Willis Richard , Richardson Ranald
Published: March 2004

This paper examines the demutualisation of the British building societies, the trend during the 1990s for these mutual financial institutions run on behalf of their members and without external shareholders to convert to public limited companies. Demutualisation resulted from cultural change within senior management in mutual societies, which undermined their support for the idea of mutual ownership. This cultural change was a consequence of the deeper integration of mutual societies into the retail financial services sector where a different business culture was dominant. Though government has ignored the wider social impact of demutualisation, it has in fact undermined their attempts to encourage more socially inclusive forms of delivery for personal financial services. The paper makes a case for recognition of the contribution of mutual building societies to the development of more socially responsible corporate strategies. The recent wave of demutuahsations also highlights the need for mutuals to encourage greater membership involvement in the running of the organisation.
Intracortical mechanism of stimulus-timing-dependent plasticity in visual cortical orientation tuning
Authors: Yao Haishan , Shen Yaosong , Dan Yang
Published: March 2004

Visual stimuli are known to induce various changes in the receptive field properties of adult cortical neurons, but the underlying mechanisms are not well understood. Repetitive pairing of stimuli at two orientations can induce a shift in cortical orientation tuning, with the direction and magnitude of the shift depending on the temporal order and interval between the pair. Although the temporal specificity of the effect on the order of tens of milliseconds strongly suggests spike-timing-dependent synaptic plasticity (STDP) as the underlying mechanism, it remains unclear whether the modification occurs within the cortex or at earlier stages of the visual pathway. In the present study, we examined the involvement of an intracortical mechanism in this functional modification. First, we measured interocular transfer of the shift induced by monocular conditioning. We found complete transfer of the effect at both the physiological and psychophysical levels, indicating that the modification occurs largely in the cortex. Second, we analyzed the spike timing of cortical neurons during conditioning and found it commensurate with the requirement of STDP. Finally, we compared the measured shift in orientation tuning with the prediction of a model circuit that exhibits STDP at intracortical connections. This model can account for not only the temporal specificity of the effect but also the dependence of the shift on both orientations in the conditioning pair. These results indicate that modification of intracortical connections is a key mechanism in the stimulus-timing-dependent plasticity in orientation tuning.
Infraslow oscillations modulate excitability and interictal epileptic activity in the human cortex during sleep
Authors: Vanhatalo S. , Palva J. M. , Holmes M. D. , Miller J. W. , Voipio J. , Kaila K.
Published: March 2004

Human cortical activity has been intensively examined at frequencies ranging from 0.5 Hz to several hundred Hz. Recent studies have, however, reported also infraslow fluctuations in neuronal population activity, magnitude of electroencephalographic oscillations, discrete sleep events, as well as in the occurrence of interictal events. Here we use direct current electroencephalography to demonstrate large-scale infraslow oscillations in the human cortex at frequencies ranging from 0.02 to 0.2 Hz. These oscillations, which are not detectable in conventional electroencephalography because of its limited recording bandwidth (typical lower limit 0.5 Hz), were observed in widespread cortical regions. Notably, the infraslow oscillations were strongly synchronized with faster activities, as well as with the interictal epileptic events and K complexes. Our findings suggest that the infraslow oscillations represent a slow, cyclic modulation of cortical gross excitability, providing also a putative mechanism for the as yet enigmatic aggravation of epileptic activity during sleep.
Similarity to peroxisomal-membrane protein family reveals that
Sinorhizobium
and
Brucella
BacA affect lipid-A fatty acids
Authors: Ferguson Gail P. , Datta Anup , Baumgartner John , Roop R. Martin , Carlson Russ W. , Walker Graham C.
Published: March 2004

Sinorhizobium meliloti
, a legume symbiont, and
Brucella abortus
, a phylogenetically related mammalian pathogen, both require the bacterial-encoded BacA protein to establish chronic intracellular infections in their respective hosts. We found that the bacterial BacA proteins share sequence similarity with a family of eukaryotic peroxisomal-membrane proteins, including the human adrenoleukodystrophy protein, required for the efficient transport of very-long-chain fatty acids out of the cytoplasm. This insight, along with the increased sensitivity of BacA-deficient mutants to detergents and cell envelope-disrupting agents, led us to discover that BacA affects the very-long-chain fatty acid (27-OHC28:0 and 29-OHC30:0) content of both
Sinorhizobium
and
Brucella
lipid A. We discuss models for how BacA function affects the lipid-A fatty-acid content and why this activity could be important for the establishment of chronic intracellular infections.
A role for heterodimerization of μ and δ opiate receptors in enhancing morphine analgesia
Authors: Gomes Ivone , Gupta Achla , Filipovska Julija , Szeto Hazel H. , Pintar John E. , Devi Lakshmi A.
Published: March 2004

Opiates such as morphine are the choice analgesic in the treatment of chronic pain. However their long-term use is limited because of the development of tolerance and dependence. Due to its importance in therapy, different strategies have been considered for making opiates such as morphine more effective, while curbing its liability to be abused. One such strategy has been to use a combination of drugs to improve the effectiveness of morphine. In particular, δ opioid receptor ligands have been useful in enhancing morphine's potency. The underlying molecular basis for these observations is not understood. We propose the modulation of receptor function by physical association between μ and δ opioid receptors as a potential mechanism. In support of this hypothesis, we show that μ-δ interacting complexes exist in live cells and native membranes and that the occupancy of δ receptors (by antagonists) is sufficient to enhance μ opioid receptor binding and signaling activity. Furthermore, δ receptor antagonists enhance morphine-mediated intrathecal analgesia. Thus, heterodimeric associations between μ-δ opioid receptors can be used as a model for the development of novel combination therapies for the treatment of chronic pain and other pathologies.
Lithium antagonizes dopamine-dependent behaviors mediated by an AKT/glycogen synthase kinase 3 signaling cascade
Authors: Beaulieu Jean-Martin , Sotnikova Tatyana D. , Yao Wei-Dong , Kockeritz Lisa , Woodgett James R. , Gainetdinov Raul R. , Caron Marc G.
Published: March 2004

Dopamine (DA) is a neurotransmitter involved in the control of locomotion, emotion, cognition, and reward. Administration of lithium salts is known to inhibit DA-associated behaviors in experimental animal models through unknown mechanisms. Here, we used a pharmacogenetic approach to show that DA can exert its behavioral effects by acting on a lithium-sensitive signaling cascade involving Akt/PKB and glycogen synthase kinase 3 (GSK-3). In the mouse striatum, increased DA neurotransmission arising either from administration of amphetamine or from the lack of the DA transporter results in inactivation of Akt and concomitant activation of GSK-3α and GSK-3β. These biochemical changes are not affected by activation of the cAMP pathway but are effectively reversed either by inhibition of DA synthesis, D2 receptor blockade, or administration of lithium salts. Furthermore, pharmacological or genetic inhibition of GSK-3 significantly reduces DA-dependent locomotor behaviors. These data support the involvement of GSK-3 as an important mediator of DA and lithium action
in vivo
and suggest that modulation of the Akt/GSK-3 pathway might be relevant to DA-related disorders, such as attention deficit hyperactivity disorder and schizophrenia.
All-trans
retinoic acid/As
2
O
3
combination yields a high quality remission and survival in newly diagnosed acute promyelocytic leukemia
Authors: Shen Zhi-Xiang , Shi Zhan-Zhong , Fang Jing , Gu Bai-Wei , Li Jun-Min , Zhu Yong-Mei , Shi Jing-Yi , Zheng Pei-Zheng , Yan Hua , Liu Yuan-Fang , Chen Yu , Shen Yang , Wu Wen , Tang Wei , Waxman Samuel , de Thé Hugues , Wang Zhen-Yi , Chen Sai-Juan , Chen Zhu
Published: March 2004

Both
all-trans
retinoic acid (ATRA) and arsenic trioxide (As
2
O
3
) have proven to be very effective in obtaining high clinical complete remission (CR) rates in acute promyelocytic leukemia (APL), but they had not been used jointly in an integrated treatment protocol for remission induction or maintenance among newly diagnosed APL patients. In this study, 61 newly diagnosed APL subjects were randomized into three treatment groups, namely by ATRA, As
2
O
3
, and the combination of the two drugs. CR was determined by hematological analysis, tumor burden was examined with real-time quantitative RT-PCR of the
PML-RAR
α (promyelocytic leukemia
-
retinoic acid receptor α) fusion transcripts, and side effects were evaluated by means of clinical examinations. Mechanisms possibly involved were also investigated with cellular and molecular biology methods. Although CR rates in three groups were all high (≥90%), the time to achieve CR differed significantly, with that of the combination group being the shortest one. Earlier recovery of platelet count was also found in this group. The disease burden as reflected by fold change of PML-RARα transcripts at CR decreased more significantly in combined therapy as compared with ATRA or As
2
O
3
mono-therapy (
P
< 0.01). This difference persisted after consolidation (
P
< 0.05). Importantly, all 20 cases in the combination group remained in CR whereas 7 of 37 cases treated with mono-therapy relapsed (
P
< 0.05) after a follow-up of 8–30 months (median: 18 months). Synergism of ATRA and As
2
O
3
on apoptosis and degradation of PML-RARα oncoprotein might provide a plausible explanation for superior efficacy of combinative therapy in clinic. In conclusion, the ATRA/As
2
O
3
combination for remission/maintenance therapy of APL brings much better results than either of the two drugs used alone in terms of the quality of CR and the status of the disease-free survival.
Effect of long-term treatment with low doses of the LHRH antagonist Cetrorelix on pituitary receptors for LHRH and gonadal axis in male and female rats
Authors: Horvath Judit E. , Toller Gabor L. , Schally Andrew V. , Bajo Ana-Maria , Groot Kate
Published: March 2004

Our previous studies showed that treatment of female rats with large doses of Cetrorelix, an antagonist of luteinizing hormone-releasing hormone (LHRH), reduces levels of serum LH, estradiol, progesterone, and the concentration of pituitary LHRH receptors (LHRH-Rs) and their mRNA expression. Serum LH and testosterone levels and pituitary LHRH-R in male rats are also decreased by high doses of Cetrorelix. This approach can be used for therapy of sex hormone-dependent cancers. However, in conditions where an incomplete hormone deprivation is indicated, lower doses of Cetrorelix may suffice. Thus, we investigated the effect of a 30-day treatment with a low-dose depot formulation of Cetrorelix (20-24 μg per kg per day) on the pituitary-gonadal axis of male and female rats. In both sexes, lower serum LH levels were observed on day 4 after administration. In males, LH returned to control levels by day 10, whereas in females, a rebound LH elevation occurred. Testosterone levels in male rats were decreased up to day 20, but on day 30, the values were similar to controls. In females, serum estradiol was reduced on day 4; however, by day 10 it returned to normal. Progesterone levels were diminished through the entire period. Female rats showed diestrous smears during the first week of treatment and prolonged estrous periods thereafter. The weights of testes and ovaries were significantly lower, but not the weights of prostate, seminal vesicles, and uterus. Pituitary LHRH-R mRNA and LHRH-R protein levels were not significantly different from the controls. Thus, the treatment with low doses of Cetrorelix did not seriously impair gonadal functions. The results suggest that Cetrorelix in low doses induces only a partial pituitary-gonadal inhibition and might be indicated for treatment of endometriosis, leiomyomas, and benign prostatic hyperplasia.
Apoptosis or growth arrest: Modulation of tumor suppressor p53's specificity by bacterial redox protein azurin
Authors: Yamada Tohru , Hiraoka Yoshinori , Ikehata Masateru , Kimbara Kazuhide , Avner Benjamin S. , Das Gupta Tapas K. , Chakrabarty Ananda M.
Published: March 2004

The tumor suppressor protein p53 is known to induce either apoptosis or growth arrest depending on cellular background. We have previously reported that a bacterial redox protein azurin induces apoptosis in J774 cell line-derived macrophages whereas a site-directed mutant M44KM64E azurin shows very little cytotoxicity and fails to induce apoptosis in J774 cells. We now report that purified M44KM64E mutant azurin protein can enter both J774 cells as well as the human breast cancer MCF-7 cells. Entry of M44KM64E mutant azurin in J774 cells causes strong inhibition of cell-cycle progression at the G
1
to S phase and a higher level of transcription of the
p21
gene. Corresponding to high p21 levels, the levels of cyclins and cyclin-dependent kinases were greatly lowered in M44KM64E mutant azurin-treated J774 cells. Interestingly, M44KM64E mutant azurin protein failed to elicit inhibition of cell-cycle progression in MCF-7 cells, presumably because of mutation at the retinoblastoma tumor suppressor protein that allows functional E2F formation in MCF-7 cells even in the presence of high intracellular p21 level. Thus, the WT azurin induces apoptosis but little inhibition of cell-cycle progression whereas the M44KM64E mutant azurin is deficient in the induction of apoptosis but mediates strong inhibition of cell-cycle progression, demonstrating the role of a single bacterial protein and its hydrophobic patch in modulating two important functions of p53.
A multiscale model for tropical intraseasonal oscillations
Authors: Majda Andrew J. , Biello Joseph A.
Published: March 2004

The tropical intraseasonal 40- to 50-day oscillation (TIO) is the dominant component of variability in the tropical atmosphere with remarkable planetary-scale circulation generated as envelopes of complex multiscale processes. A new multiscale model is developed here that clearly demonstrates the fashion in which planetary-scale circulations sharing many features in common with the observational record for the TIO are generated on intraseasonal time scales through the upscale transfer of kinetic and thermal energy generated by wave trains of organized synoptic-scale circulations having features in common with observed superclusters. The appeal of the multiscale models developed below is their firm mathematical underpinnings, simplicity, and analytic tractability while remaining self-consistent with key features of the observational record. The results below demonstrate, in a transparent fashion, the central role of organized vertically tilted synoptic-scale circulations in generating a planetary circulation resembling the TIO.
Dynamics of coilin in Cajal bodies of the
Xenopus
germinal vesicle
Authors: Deryusheva Svetlana , Gall Joseph G.
Published: March 2004

Cajal bodies (CBs) are complex organelles found in the nuclei of a wide variety of organisms, including vertebrates, invertebrates, plants, and yeast. In most cell types CBs are <1 μm in diameter, severely limiting the range of experimental observations that can be made on them. By contrast, CBs in the amphibian oocyte nucleus (also called the germinal vesicle) are 2–10 μm in diameter. We have taken advantage of this large size to carry out kinetic studies on coilin, a protein that is specifically enriched in CBs. We labeled coilin with photoactivatable green fluorescent protein and analyzed the movement of the protein by confocal microscopy in unfixed germinal vesicles isolated in oil. We showed that coilin leaves the CB relatively slowly (minutes rather than seconds) with kinetics similar to earlier measurements on its entrance. We also showed that coilin diffuses very slowly within the CB, consistent with its being in a large macromolecular complex. Finally, we found that the movement of coilin is not directly affected by the transcriptional state of the nucleus or ongoing nucleocytoplasmic exchange. These data on the kinetics of coilin reinforce the conclusion that CB components are in a constant state of flux, consistent with models that postulate an active role for CBs in nuclear physiology.
Localization and activity of the SNARE Ykt6 determined by its regulatory domain and palmitoylation
Authors: Fukasawa Masayoshi , Varlamov Oleg , Eng William S. , Söllner Thomas H. , Rothman James E.
Published: March 2004

Soluble
N
-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) catalyze compartment-specific membrane fusion. Whereas most SNAREs are bona fide type II membrane proteins, Ykt6 lacks a proteinaceous membrane anchor but contains a prenylation consensus motif (CAAX box) and exists in an inactive cytosolic and an active membrane-bound form. We demonstrate that both forms are farnesylated at the carboxyl-terminal cysteine of the CCAIM sequence. Farnesylation is the prerequisite for subsequent palmitoylation of the upstream cysteine, which permits stable membrane association of Ykt6. The double-lipid modification and membrane association is crucial for intra-Golgi transport
in vitro
and cell homeostasis/survival
in vivo
. The membrane recruitment and palmitoylation is controlled by the N-terminal domain of Ykt6, which interacts with the SNARE motif, keeping it in an inactive closed conformation. Together, these results suggest that conformational changes control the lipid modification and function of Ykt6. Considering the essential and central role of Ykt6 in the secretory pathway, this spatial and functional cycle might provide a mechanism to regulate the rate of intracellular membrane flow.
Interactive journal concept for improved scientific publishing and quality assurance
Authors: Pöschl Ulrich
Published: March 2004

Many scientific publications are careless, useless or false, and inhibit scholarly communication and scientific progress. This is caused by the failure of traditional journal publishing and peer review to provide efficient scientific exchange and quality assurance in today's highly diverse world of science. The most promising way to improve matters is a two‐stage (or multi‐stage) publication processes with interactive peer review and public discussion in new and traditional scientific journals. A concept for such interactive scientific journals is outlined, and its applicability is demonstrated by the open access journal Atmospheric Chemistry and Physics.
Institutional repositories and scholarly publishing
Authors: Ware Mark
Published: March 2004

The institutional repository (IR), an open Web‐based archive of scholarly material produced by the members of a defined institution, has come to the fore following the launch of DSpace at MIT at the end of 2002. Here we review recent developments in IRs and explore the impact their expansion may have on scholarly publishing.
A historical review of the chemistry periodical literature until 1950
Authors: Cooke Helen
Published: March 2004

The periodical, or journal, is the means by which most scientific information is communicated. This paper examines the origins and evolution of journals covering chemistry.
Book Reviews
Authors: Halsall Janet , Smart Pippa , Watkinson Anthony
Published: March 2004

Indexing and Abstracting in Theory and Practice, 3rd edn, by F. W. Lancaster Facet Publishing 2003, 464 pp., ISBN 1‐85604‐482‐3, £39.95

Science Editors' Handbook European Association of Science Editors 2003, ISBN 0‐905988‐13‐2, £18

Digital Preservation: The Record of Science, edited by Barry Mahon and Elliot Siegel IOS Press, 2002, 143 pp., ISBN 1‐58603‐317‐4, paperback £65.00
Capillary Flow and Diameter Changes during Reperfusion after Global Cerebral Ischemia Studied by Intravital Video Microscopy
Authors: Hauck Erik F. , Apostel Sebastian , Hoffmann Julie F. , Heimann Axel , Kempski Oliver
Published: March 2004

The reaction of cerebral capillaries to ischemia is unclear. Based on Hossmann's observation of postischemic “delayed hypoperfusion,” we hypothesized that capillary flow is decreased during reperfusion because of increased precapillary flow resistance. To test this hypothesis, we measured cerebral capillary erythrocyte velocity and diameter changes by intravital microscopy in gerbils. A cranial window was prepared over the frontoparietal cortex in 26 gerbils anesthetized with halothane. The animals underwent either a sham operation or fifteen minutes of bilateral carotid artery occlusion causing global cerebral ischemia. Capillary flow velocities were measured by frame-to-frame tracking of fluorescein isothiocyanate labeled erythrocytes in 1800 capillaries after 1-hour reperfusion. Capillary flow velocities were decreased compared to control (0.25 ± 0.27mm/s vs. 0.76 ± 0.45 mm/s; P < 0.001). Precapillary arteriole diameters in reperfused animals were reduced to 76.3 ± 6.9% compared to baseline ( P < 0.05). Capillary diameters in reperfused animals (2.87 ± 0.97 μm) were reduced ( P < 0.001) compared to control (4.08 ± 1.19 μm). Similar reductions of precapillary (24%) and capillary vessel diameters (30%) and absolute capillary flow heterogeneity indicate that delayed (capillary) hypoperfusion occurs as a consequence of increased precapillary arteriole tone during reperfusion.
Synaptic P2X7 and Oxygen/Glucose Deprivation in Organotypic Hippocampal Cultures
Authors: Cavaliere Fabio , Amadio Susanna , Sancesario Giuseppe , Bernardi Giorgio , Volonté Cinzia
Published: March 2004

The P2X7 receptor for extracellular ATP is the main candidate, among P2 receptors, inducing cell death in the immune system. Here, we demonstrate the direct participation of this receptor to cell damage induced by oxygen/glucose deprivation, in the ex vivo model of organotypic hippocampal cultures. By pharmacological and immunological approaches, we show that P2X7 is rapidly and transiently up regulated in hippocampal areas eliciting metabolism impairment. Moreover, the P2 antagonists 2′,3′,-dialdehyde ATP and reactive blue 2 prevent both up regulation of this receptor and hypoxic/hypoglycemic damage. By confocal laser microscopy, we show that P2X7 is present at the synaptic level of fibers extending from the CA1–2 pyramidal cell layer throughout the strata oriens and radiatum, but absent on oligodendrocytes, astrocytes or neuronal cell bodies. Colocalization of P2X7 is obtained with neurofilament-L protein and with synaptophysin, not with myelin basic protein, glial fibrillary acidic protein or a marker for neuronal nuclei. P2X7 up regulation and diffuse cellular damage are also induced by 3′-O-(4-benzoyl) benzoyl-ATP, an agonist selective but not exclusive for P2X7.

In summary, our study demonstrates that P2X7 not only directly participates to the hypoxic/hypoglycemic process, but also owns specific phenotypic localization. We do not exclude that it might serve as a sensor of dysregulated neuronal activity and ATP release, both occurring during oxygen/glucose deprivation.
Post-ischemic Administration of Heparin-Binding Epidermal Growth Factor-like Growth Factor (HB-EGF) Reduces Infarct Size and Modifies Neurogenesis after Focal Cerebral Ischemia in the Rat
Authors: Jin Kunlin , Sun Yunjuan , Xie Lin , Childs Jocelyn , Mao Xiao Ou , Greenberg David A.
Published: March 2004

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a hypoxia-inducible, neuroprotective protein that also stimulates proliferation of neuronal precursor cells. Accordingly, HB-EGF may contribute to recovery from cerebral injury through direct neuroprotective effects, by enhancing neurogenesis, or both. When administered by the intracerebroventricular route 1–3 days after focal cerebral ischemia in adult rats, HB-EGF decreased the volume of the resulting infarcts and reduced post-ischemic neurological deficits. HB-EGF also increased the incorporation of bromodeoxyuridine into cells expressing the immature neuronal marker protein TUC-4 in the dentate subgranular and rostral subventricular zones, consistent with increased proliferation of neuronal precursors. However, HB-EGF decreased the number of newborn neurons that migrated into the ischemic striatum, perhaps partly because reduction of infarct size by HB-EGF also reduced the stimulus to migration. To determine if HB-EGF might also directly inhibit migration of neuronal precursors, we co-cultured subventricular zone (SVZ) explants treated with HB-EGF or vehicle together with hypoxic cerebral cortical explants, and measured cell migration from the former toward the latter. HB-EGF reduced directed migration of SVZ cells toward the cortical explants, possibly due to a local chemoattractant effect on neuronal precursor cells, which may be mediated through the HB-EGF-specific receptor, N-arginine dibasic convertase. The delayed neuroprotective effect of HB-EGF may have implications for efforts to prolong the therapeutic window for intervention in stroke.
Caspase Inhibitors Prevent Endothelial Apoptosis and Cerebral Vasospasm in Dog Model of Experimental Subarachnoid Hemorrhage
Authors: Zhou Changman , Yamaguchi Mitsuo , Kusaka Gen , Schonholz Claudio , Nanda Anil , Zhang John H.
Published: March 2004

Apoptosis in the endothelium of major cerebral arteries may play a role in the initiation and maintenance of cerebral vasospasm after subarachnoid hemorrhage (SAH). We tested the therapeutic effect of caspase inhibitors on endothelial apoptosis and on cerebral vasospasm in an established dog double-hemorrhage model. Thirty-one mongrel dogs were divided into five groups: control; SAH; SAH treated with vehicle [DMSO]; SAH treated with Ac-DEVD-CHO [a specific caspase-3 inhibitor]; and SAH treated with Z-VAD-FMK [a broad caspase inhibitor]. The inhibitors (100 μM) were injected into the cisterna magna daily from Day 0 through Day 3. Angiography was performed on Day 0 and Day 7. Histology, TUNEL staining, and immunohistochemistry were conducted on basilar arteries collected on Day 7 after SAH. Positive staining of TUNEL, poly(ADP)-ribose polymerase (PARP), caspase-3, and caspase-8 was observed in the endothelial cells of the spastic arteries. Double fluorescence labeling demonstrated co-localization of TUNEL with caspase-3 and TNFα-receptor-1 (TNFR1). Ac-DEVD-CHO and Z-VAD-FMK prevented endothelial apoptosis and reduced angiographic vasospasm. The mechanism of apoptosis in endothelial cells involves TNFR1 and the caspase-8 and caspase-3 pathways. Caspase inhibitors may have potential in the treatment of cerebral vasospasm.
Delayed Onset of Prolonged Hypothermia Improves Outcome after Intracerebral Hemorrhage in Rats
Authors: MacLellan Crystal L. , Girgis Jacklyn , Colbourne Frederick
Published: March 2004

Prolonged hypothermia reduces ischemic brain injury, but its efficacy after intracerebral hemorrhagic (ICH) stroke is unresolved. Rats were implanted with core temperature telemetry probes and subsequently subjected to an ICH, which was produced by infusing bacterial collagenase into the striatum. Animals were kept normothermic (NORMO), or were made mildly hypothermic (33–35°C) for over 2 days starting 1 hour (HYP-1), 6 hours (HYP-6), or 12 hours (HYP-12) after collagenase infusion. Others were cooled for 7 hours beginning 1 hour after infusion (BRIEF). Skilled reaching, walking, and spontaneous forelimb use were assessed. Normothermic ICH rats sustained, on average, a 36.9-mm3 loss of tissue at 1 month. Only the HYP-12 group had a significantly smaller lesion (25.5 mm3). Some functional improvements were found with this and other hypothermia treatments. Cerebral edema was observed in NORMO rats, and was not lessened significantly by hypothermia (HYP-12). Blood pressure measurements, as determined by telemetry, in BRIEF rats showed that hypothermia increased blood pressure. This BRIEF treatment also resulted in significantly more bleeding at 12 hours after ICH (79.2 μL) versus NORMO-treated rats (58.4 μL) as determined by a spectrophotometric hemoglobin assay. Accordingly, these findings suggest that early hypothermia may fail to lessen lesion size owing to complications, such as elevated blood pressure, whereas much-delayed hypothermia is beneficial after ICH. Future experiments should assess whether counteracting the side effects of early hypothermia enhances protection.
The Angiotensin II Type 1—Receptor Blocker Candesartan Increases Cerebral Blood Flow, Reduces Infarct Size, and Improves Neurologic Outcome after Transient Cerebral Ischemia in Rats
Authors: Engelhorn Tobias , Goerike Sophia , Doerfler Arnd , Okorn Christine , Forsting Michael , Heusch Gerd , Schulz Rainer
Published: March 2004

The goal of the present study was to test the impact of administration time of the angiotensin II type 1–receptor blocker candesartan on cerebral blood flow (CBF), infarct size, and neuroscore in transient cerebral ischemia. Therefore, 1-hour middle cerebral artery occlusion (MCAO) was followed by reperfusion. Rats received 0.5-mg/kg candesartan intravenously 2 hours before MCAO (pretreatment), 24 hours after MCAO, every 24 hours after MCAO, or 2 hours before and every 24 hours after MCAO. Infarct size (mm3) and a neuroscore at day 7 were compared with controls. CBF was quantified by radiolabeled microspheres and laser-Doppler flowmetry. Compared with controls (95 ± 8), infarct size in candesartan-treated groups was smaller (59 ± 5, 68 ± 10, 28 ± 3, and 15 ± 3, respectively; P < 0.05). Although there was no difference in neuroscore between pretreatment and controls (1.55 ± 0.18, 1.80 ± 0.13), other treatment regimens resulted in improved neuroscores (1.33 ± 0.16, 1.11 ± 0.11, 0.73 ± 0.15; P < 0.05). CBF in pretreated animals at 0.5 hours after MCAO was significantly higher than in controls (0.58 ± 0.09 mL · g−1 ·· min−1 and 44% ± 7% of baseline compared with 0.49 ± 0.06 mL · g−1 ·· min−1 and 37% ± 6%, microspheres and laser-Doppler flowmetry; P < 0.05). Thus, candesartan reduces infarct size even if administered only during reperfusion. Apart from pretreatment, other treatment regimens result in significantly improved neuroscores. In the acute phase of cerebral ischemia, candesartan increases CBF.
Why emerging roles for health sciences librarians?
Authors: Shipman Jean P.
Published: March 2004

Health sciences librarians no longer find themselves only staffing reference desks or building collections. Their activities range from being active participants in health‐care teams to providing training to the general public. Emerging roles are surfacing in all arenas served by health sciences libraries: educational, clinical, research, and administration. Librarians are meeting new skill demands by re‐educating both on the job and through traditional coursework. New types of positions are being explored and new partnerships with health‐care colleagues are being forged. This article highlights the reasons why these new opportunities exist and provides references to articles contained within this journal issue.
Emerging roles of health sciences librarians: academic library centrality
Authors: Barbara Watstein Sarah
Published: March 2004

The emerging roles of health sciences librarians are considered within the context of changes and challenges facing both the profession of librarianship and the library. Suggests that the emerging – and increasingly relevant – roles of health sciences librarians contribute to the establishment of health sciences libraries’ centrality within their institutions. Rationale is provided for library and information science professionals outside the health sciences arena to maintain awareness of emerging roles, evolving status, and contributions of their colleagues.
PDA librarian
Authors: Rios Gabriel R.
Published: March 2004

The Claude Moore Health Sciences Library at the University of Virginia is one of several libraries taking a leadership role with personal digital assistants (PDAs). The mission of the Library is to provide information management expertise and institutional leadership to connect students, researchers, clinicians and staff with the biomedical information they need to advance the education, research, patient care and public service programs of the University of Virginia Health System. As a corollary to the mission, the Library’s PDA services are built around the premise that users need the skills and knowledge to effectively use PDAs in their workflow.
Teaching a Web‐based course in health informatics
Authors: Turman Lynne U. , Self Phyllis C. , Calarco Pascal V.
Published: March 2004

Librarians at Virginia Commonwealth University teach a course in Health Informatics as part of a distance learning Doctoral program for allied health professionals. This paper discusses the experience of developing and delivering a Web‐based course for the curriculum. Lessons learned fall into the categories of communication, technology, and resources.
Campus intellectual property policy development
Authors: Nollan Richard
Published: March 2004

The evolution of the Internet and information technology in the last 20 years has been breathtakingly rapid, and promises to continue so. Faculty members in academic health centers have struggled to incorporate the new technology into the classroom and the laboratory but, in so doing, many questions arise regarding ownership and control of these new digital creations. These questions have led institutions to revisit their intellectual property (IP) policies. Librarians can play an important role in any effort to review IP policy. They already have a basic and applied understanding of copyright law and are often more knowledgeable than many of their colleagues. By taking the lead in updating or developing an IP policy, such as by chairing the committee, librarians can contribute to the institution in a way that cannot be done from inside the library, and can also provide a new context for measuring the librarian’s contribution to the institution.