bluuebunny/crossref_metadata_2025 huggingface dataset:
Beyond acetylcholine: Next steps for sleep and memory research
Authors: Payne Jessica D. , Britton Willoughby B. , Bootzin Richard R. , Nadel Lynn
Published: July 2005

We consider Walker's thorough review in the context of thinking about future research on the relation between sleep and memory. We first address methodological issues including type of memory and sleep-stage dependency. We suggest a broader investigation of potential signaling molecules that may be critical to sleep-related consolidation. A brief review of the importance of the stress hormone cortisol illustrates this point.
Rules and similarity – a false dichotomy
Authors: Hampton James A.
Published: July 2005

Unless restricted to explicitly held, sharable beliefs that control and justify a person's behavior, the notion of a rule has little value as an explanatory concept. Similarity-based processing is a general characteristic of the mind-world interface where internal processes (including explicitly represented rules) act on the external world. The distinction between rules and similarity is therefore misconceived.
REM sleep, dreaming, and procedural memory
Authors: Schredl Michael
Published: July 2005

In this commentary the “incredibly robust” evidence for the relationship between sleep and procedural memory is questioned; inconsistencies in the existing data are pointed out. In addition, some suggestions about extending research are made, for example, studying REM sleep augmentation or memory consolidation in patients with sleep disorders. Last, the possibility of a relationship between dreaming and memory processes is discussed.
It's not how many dimensions you have, it's what you do with them: Evidence from speech perception
Authors: McMurray Bob , Gow David
Published: July 2005

Contrary to Pothos, rule- and similarity-based processes cannot be distinguished by dimensionality. Rather, one must consider the goal of the processing: what the system will do with the resulting representations. Research on speech perception demonstrates that the degree to which speech categories are gradient (or similarity-based) is a function of the utility of within-category variation for further processing.
The incredible, shrinking sleep-learning connection
Authors: Siegel Jerome M.
Published: July 2005

Initial claims that REM sleep is important in the consolidation of all memories have been revised and reduced to the claim that sleep has a role only in the consolidation of procedural learning. Now, Walker hypothesizes that sleep has no role in the “stabilization phase of consolidation” but only in the “enhanced learning” phase of procedural learning. Evidence for this vague, truncated hypothesis remains as inconsistent as that for prior claims.
Avian assimilation and dispersal of carbon and nitrogen brought ashore by breeding Westland petrels (Procellaria westlandica): a stable isotope study
Authors: Hawke D. J. , Holdaway R. N.
Published: July 2005

Only a small proportion of the marine nutrients brought ashore by breeding colonial seabirds is retained in colony soils. However, means by which these marine nutrients can be dispersed to the wider terrestrial ecosystem have rarely been identified. In this study, moulted feathers from Hemiphaga novaeseelandiae (an endemic pigeon; n=9) and Gallirallus australis (an endemic flightless rail; n=3) and from a Procellaria westlandica (Westland petrel) colony were analysed for 13C and 15N enrichment. Potential diet items from both the colony and a control location were also analysed, and their contributions to the diets of H. novaeseelandiae and G. australis calculated. Hemiphaga novaeseelandiae assimilated marine N but not marine C, and showed a wide range in the significance of different diet sources. Food for most H. novaeseelandiae came from within the colony, implying minimal transport of marine nutrients to the wider terrestrial environment. All G. australis food came from within the colony, but 29–39% was from petrel tissue, or invertebrates feeding on petrel material. Thus, both H. novaeseelandiae and G. australis assimilated nutrients brought ashore by P. westlandica, but neither was shown to disperse the nutrients much beyond the petrel colony. However, birds that are now locally extinct may have dispersed marine nutrients more widely. Future research should focus on the consequences of restoring these species to petrel colonies as part of attempts to re‐establish the functioning of pre‐human ecosystems in New Zealand.
The Proceedings of the Zoological Society of London, 1859–1900: an exploration of breaks between calendar years of publication
Authors: Dickinson Edward C.
Published: July 2005

Duncan (1937) provided detailed information that has been widely used to date names of new taxa described in early volumes of the Proceedings. The examinations reported here suggest that at least at the point where the year of publication is important Duncan was usually correct, and although exceptions are reported they are not of great consequence (although 14 of 42 volumes are anomalous). These exceptions relate to cases where the published pages differed from a multiple of the signature size by a couple of pages or so. Over the 41 volumes examined, two or more techniques were used to provide, economically, text needed to complete an article that would have over‐run the number of signatures planned for the issue. The importance of retaining wrappers and binding them in is demonstrated by what can be learned from them.
The short‐term effect of sheep grazing on selected invertebrates (Diptera and Hemiptera) relative to other environmental factors in an alpine ecosystem
Authors: Mysterud Atle , Ove Hansen Lars , Peters Chris , Austrheim Gunnar
Published: July 2005

Grazing by large herbivores is well‐known to influence plant communities, while much fewer studies have been carried out on grazing effects on invertebrates. In Norway, some 2.2 million sheep graze on outlying pastures during summer, most of them in the alpine zone, but no study has reported the relative impact of sheep grazing on invertebrate communities relative to other environmental factors such as the plant community and altitude. A fully replicated landscape‐scale experiment (2.7 km2) was performed with no, low (25 per km2) and high (80 per km2) sheep densities in an alpine habitat of Norway (1050–1300 m a.s.l.).The increased vulnerability hypothesis(H1) predicts that the more folivorous invertebrates, the higher the grazing pressure by sheep, as large herbivore grazing may stress the plants so they are more vulnerable to insect herbivory.The increased defence hypothesis(H2) predicts increased levels of general anti‐herbivore defences, and thus a lower abundance of invertebrates with increasing sheep densities. Contrary to both predictions, no evidence was found that sheep grazing affected invertebrate richness, or abundance of folivorous, predatory or detritivore invertebrates – in a community dominated by Diptera and Hemiptera. Demonstrating an effect will always be a function of sample size, but at least our study shows that other environmental variables (such as plant species richness and functional plant richness) are more important determinants than sheep grazing for the selected invertebrate groups. Our study was short‐term (first year of grazing) mainly designed to test specific hypotheses related to induced plant defences; long‐term effects are probably owing to the impact sheep may have on vegetation composition, primary production, litter cover and soil properties.
Embryos produced in vitro from bulls carrying 16;20 and 1;29 Robertsonian translocations: efficiency and kinetics of oocyte fertilization and embryo development
Authors: Machatkova M. , Horakova J. , Rybar R. , Hanzalova K. , Rubes J.
Published: July 2005

The present experiments were designed to study the effects of Robertsonian translocations on the efficiency and kinetics of in vitro fertilization and early and advanced embryo development. Spermatozoa from bulls with rob(16;20), rob(1;29) and normal karyotype (A, B and C, respectively) were used. Oocytes were matured, fertilized and cultured by the standard protocol described previously. Twenty-four hours after fertilization, adequate numbers of oocytes were fixed, stained and examined. The development of embryos was evaluated on days 2 (D2), 7 (D7) and 8 (D8) after fertilization. The rate of normally fertilized oocytes was significantly lower (p≤0.01) for bull A than for bulls B and C. However, no significant differences in the kinetics of fertilization were found between bulls A, B and C. The D2 cleavage rate of embryos was significantly lower (p≤0.01) for bull A than for bulls B and C. Both D7 and D8 blastocyst rates for bull A or bull B were significantly lower (p≤0.01 or p≤0.01) than those for bull C. The percentages of both D7 advanced blastocysts and D8 expanded blastocysts were significantly lower (p≤0.01) for bulls A and B than for bull C. In conclusion, for rob(16;20), the efficiency of fertilization was strongly reduced; it resulted in low early and advanced embryo development. On the other hand, for the rob(1;29), neither fertilization nor early embryo development were affected and only advanced embryo development was decreased. But for both translocations, blastocyst formation was significantly delayed.
Comparison of three in vitro culture systems for maturation of early preantral mouse ovarian follicles
Authors: Mousset-Siméon Nathalie , Jouannet Pierre , Le Cointre Laëtitia , Coussieu Christiane , Poirot Catherine
Published: July 2005

The aim of this study was to compare three different culture systems for in vitro follicular growth and oocyte maturation in ovarian follicles of mice in order to assess the technique with the optimal growth and improved rate of meiotic maturation. The three systems tested were culture under oil, on a hydrophobic membrane and on agar respectively. Early preantral follicles were cultured for 12 days in α-MEM GlutaMAX medium. Follicular growth, oocyte meiotic maturation, oocyte extrusion, atresia and estradiol production were analysed. Follicular development showed two phases in the three systems, with slow growth before day 5 and subsequent acceleration. The percentage of follicles transferred into oocyte maturation medium was significantly higher after culture under oil. The proportion of oocytes that achieved nuclear maturation (metaphase II) was higher when follicles were cultured under oil or on a hydrophobic membrane than on agar. Our results support the use of culture under oil for in vitro follicular growth from the early preantral stage in order to obtain metaphase II oocytes. Fertilization ability of these oocytes and the capacity to obtain healthy mice in a reproducible manner warrants further investigation.
Plasminogen detection in oocytes and plasminogen activator activities in the porcine oviduct during the estrous cycle
Authors: Roldán-Olarte Mariela , Jiménez-Díaz María , Miceli Dora C.
Published: July 2005

Plasminogen activators (PAs) are highly specific serine proteases that convert the extracellular zymogen plasminogen into the active proteinase plasmin. Plasminogen-dependent proteolytic activity was detected by zymography both in the tissue membrane fraction of oviducts and in the oviductal flushing obtained at the preovulatory (Pre-Ov), postovulatory (Post-Ov) and mid-luteal (Mid-L) stages of the estrous cycle. A main proteolytic band, with a relative mobility similar to a human melanoma cell tissue-type plasminogen activator (t-PA), was found in all samples. Two additional components were observed in Pre-Ov and Post-Ov oviductal flushing but not in the tissue membrane fraction. In the oviductal flushing the PA activity was significantly higher in the Post-Ov stage than in the Pre-Ov one. Both urokinase-type plasminogen activator (u-PA, 50 kDa) and t-PA (72 kDa) were detected by Western blot; they showed differences in their relative concentration between Post-Ov and Pre-Ov oviductal flushing. The main PA substrate, plasminogen, was detected by indirect immunofluorescence in the cumulus cell extracellular matrix (ECM) and oocyte zona pellucida (ZP). In denuded oocytes, plasminogen was also detected on the surface of the plasma membrane. It is possible that oviductal PAs may act on the plasminogen present in the cumulus cell ECM and ZP; consequently, the generated plasmin could be involved in the rebuilding or degradation of these oocyte structures during fertilization or early development.
Medium effects on capacitation and sperm penetration through the zona pellucida in inbred BALB/c spermatozoa
Authors: Kito Seiji , Ohta Yuki
Published: July 2005

Inbred BALB/c mice are one of the most difficult inbred strains to fertilize in vitro. In this study we examined the abilities of various media used for mouse in vitro fertilization (IVF) to support capacitation and sperm penetration through the zona pellucida (ZP) of inbred BALB/c spermatozoa. Media examined were TYH, M16, CZB, mWhitten medium, T6, modified Tyrode's solution (mTyrode's), mKSOM, MEM and TCM199. Modified human tubal fluid (mHTF) was used as a control medium. When sperm were capacitated and inseminated in the same medium, mHTF showed the best fertilization (approximately 80%) scored by male pronuclear formation (<26%) at 5 h post-insemination (PI). When sperm were capacitated in various media and inseminated in mHTF, sperm capacitated in TYH solution (93%) but no other media (<45%) showed a significantly higher level of sperm nuclear decondensation (SND) than mHTF at 2 h PI (approximately 65%). When sperm were capacitated in mHTF and inseminated in various media, only mTyrode's (52%) was not significantly lower than mHTF (66%) in terms of SND at 2 h PI (<49%). Sperm capacitation also was examined by chlortetracycline (CTC) staining. Sperm capacitated in TYH solution showed a significantly higher percentage of capacitation (46%) than those treated in HTF (28%) and other media (<24%). These results indicate that the best approach for IVF in the BALB/c strain is capacitation in TYH and insemination in mHTF. Poor fertilization of BALB/c may result from suboptimal conditions of sperm capacitation and insemination, and overall IVF success may differ depending on strains used.
Microtubule and microfilament organization in immature, in vitro matured and in vitro fertilized prepubertal goat oocytes
Authors: Velilla Esther , Rodríguez-Gonzalez Elisabet , Vidal Francesca , Paramio Maria-Teresa
Published: July 2005

The aim of our study was to analyse the cytoskeletal organization of prepubertal goat oocytes. Microtubule and microfilament organization during in vitro maturation of prepubertal and adult goat oocytes and presumptive zygotes of in vitro matured–in vitro fertilized (IVM-IVF) prepubertal goat oocytes were analysed. Oocytes were matured in M-199 with hormones and serum and inseminated with frozen-thawed spermatozoa. Oocytes and presumptive zygotes were treated with anti-α-tubulin antibody and fluorescein isothiocyanate (FITC)-labelled goat anti-mouse antibody to stain the microtubules. Microfilaments were localized by means of phalloidin 5 μg/ml conjugated with fluorescein isothiocyanate (FITC-phalloidin). DNA was stained with propidium iodide. Stained oocytes were observed under a confocal laser scanning microscope. At the germinal vesicle nuclear stage, microfilaments were distributed at the cortex of the oocytes. After in vitro maturation, 91.7% of metaphase II (MII) oocytes from adult goats displayed microfilaments in the cortex and within the polar body and were characterized by the presence of a microfilament thickening at the cortical region over the meiotic spindle. In prepubertal goat MII oocytes only 5.7% of oocytes displayed microfilaments at the cortex and within the polar body. After insemination, most of the zygotes displayed microfilaments distributed at the cortex. An undefined microtubular network was observed in adult and prepubertal goat oocytes at the germinal vesicle stage. After in vitro maturation, 100% of MII oocytes from adult goats displayed microtubules on the meiotic spindle and within the polar body. This pattern of distribution was observed in 71.6% of prepubertal goat oocytes. Undefined microtubule networks were present in most of the zygotes analysed. In conclusion, cytoskeletal differences were found between prepubertal and adult goat MII oocytes. Furthermore, most of the zygotes from IVM-IVF prepubertal goat oocytes displayed cytoskeletal anomalies.
A pilot study of the impact of a grief camp for children
Authors: NABORS LAURA , OHMS MARSHAE , BUCHANAN NATASHA , KIRSH KENNETH L. , NASH TIFFANY , PASSIK STEVEN D. , JOHNSON JONI L. , SNAPP JANET , BROWN GRETCHEN
Published: July 2005

Objective:Research indicates that children benefit from supportive interventions to help them cope with the loss of a loved one. The aim of this pilot study was to evaluate children's perceptions of the effectiveness of a grief camp.

Methods:Semistructured interviews were performed with 18 children who attended a weekend-long grief camp. Children also responded to follow-up interviews via telephone. Their parents also completed surveys before camp began and either after camp ended or at a follow-up evaluation. Data were analyzed using descriptive statistics and content coding to uncover key themes in the interviews.

Results:Children reported that art activities helped them to express feelings about their grief and release feelings of sadness and worry related to the death. Parents and children felt that the camp was a positive experience and that the children benefited from being in groups with peers who had also lost family members.

Significance of results: Evaluating the impact of grief camps, using practical methods such as the ones for this study, is important, as these camps are becoming more popular interventions. Children and parents may benefit from contact at specified follow-up periods after camp to determine if they would benefit from further therapy. Results also provide evidence of the success of this program, which supports the need for funding these types of interventions.
Somatization disorder and cancer: A case history and review
Authors: THOMAS TABITHA , BOOTH SARA , EARL HELENA , LENNOX GRAHAM
Published: July 2005

Cancer pain generally has a physical cause exacerbated to varying
degrees by psychological, social, and spiritual factors. This article
describes the case history of a cancer patient with severe pain for which
no physical cause could be found, who was subsequently found to have a
history of somatization disorder. There follows a review of the
literature, with specific reference to the difficulties of managing
somatization in the context of cancer.
Regulation of neurogenesis by neurotrophins: implications in hippocampus-dependent memory
Authors: LU BAI , CHANG JAY H.
Published: July 2005

Neurogenesis, the generation of new neurons from neural precursor cells (NPCs), is a multi-step process that includes the proliferation of NPCs, fate determination, migration, and neuronal maturation. Neurogenesis is regulated by several extrinsic factors, such as enriched environment, physical exercise, hormones and stress, many of which also induce the expression of neurotrophins. In this review, we summarize studies on the role of neurotrophins in neurogenesis during development and in adults. We discuss the functional significance of neurogenesis in learning and memory, and how neurotrophins regulate this process. In this context, we describe recent experiments linking adult neurogenesis to long-term synaptic plasticity in the hippocampal dentate gyrus. Further study of the relationship between neurotrophins, adult neurogenesis and dentate synaptic plasticity might provide new insights into the mechanisms by which gene–environment interactions control cognition and brain plasticity.
Toward Interplanetary Space Weather: Strategies for Manned Missions to Mars
Authors: Foullon Claire , Heynderickx Daniel , Crosby Norma
Published: July 2005

Analysis of the interplanetary space weather environment will contribute to reducing uncertainties and assuring crew radiation safety.
Insulation and depletion due to thickened crust: Effects on melt production on Mars and Earth
Authors: O'Neill C. , Moresi L. , Lenardic A.
Published: July 2005

The growth of thickened crustal units both depletes the mantle of heat producing elements, and thermally insulates it. These effects either cool or heat the mantle, respectively, and play an important role in subsequent crustal formation. We employ mantle convection models including thickened crustal units of variable heat production to show that for increasing crustal extent, mantle temperatures and melt production can either increase of decrease, depending on the degree of enrichment of the crust with respect to the mantle, the total heat production, and the Rayleigh number. The formation of the continents on Earth efficiently cooled the upper mantle, resulting in lower subsequent rates of melt production and continental formation. In contrast, the growth of the Martian highlands would have raised the temperatures of the Martian mantle, increasing rates of melt production, and leading to runaway crustal growth. This would have continued as long as the lithosphere of Mars was mobile.
Retrieval of global hydrogen peroxide (H2O2) profiles using ENVISAT‐MIPAS
Authors: Papandrea E. , Dudhia A. , Grainger R. G. , Vancassel X. , Chipperfield M. P.
Published: July 2005

We have used spectra from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) to perform the first global retrievals of stratospheric H2O2. We demonstrate the feasibility of profile retrievals in the range 6–35 km and obtain zonal mean maps that average profiles computed from consecutive MIPAS orbits for the periods: December 2002, March, June and September 2003. The retrieved H2O2 values show an equatorial mid‐stratospheric peak, enhanced values in the Antarctic springtime lower stratosphere, and diurnal/seasonal variability. Our retrieved H2O2 profiles are in qualitative agreement with expected photochemistry and with a previous balloon flight.
Slab pull, slab weakening, and their relation to deep intra‐slab seismicity
Authors: Bilek Susan L. , Conrad Clinton P. , Lithgow‐Bertelloni Carolina
Published: July 2005

Subduction zone seismicity is highly variable. Great earthquakes occur at few subduction zones around the world, with significant variation in size and frequency of deep events. Interactions between overriding and subducting plates and slab pull strength for individual plates provide a framework for understanding these variations. Previous work suggests an inverse correlation between great earthquake moment release and the degree to which the subducted slab is connected to the surface plate. We find positive correlations between degree of plate‐slab attachment and moment release from intermediate and deep earthquakes. This implies that shallow slab weakening that occurs at trenches where compressive stresses (and great earthquakes) dominate not only detaches slabs from plates, but is maintained as the slab descends, discouraging deep seismicity. Regions of low shallow moment release are consistent with extensional shallow stress regimes and undamaged slabs. Such slabs maintain mechanical strength during descent and deform seismogenically at depth.
Ground level muons coincident with the 20 January 2005 solar flare
Authors: D'Andrea C. , Poirier J.
Published: July 2005

An array of proportional wire chamber stations, Project GRAND, detects secondary muons produced by hadronic primaries. The muon counting rate at ground level increases above the average background intensity with a statistical significance of 10σ. This ground level event (GLE), caused by solar energetic particles, is detected in close time association with an X7.1 X‐Ray flare on 20 January 2005. The statistical significance of this event rises to 18σ when an angular window of the sky near zenith is studied. These data are compared with data from neutron monitors.
Longitudinal dispersion and lateral circulation in the intertidal zone
Authors: Ralston David K. , Stacey Mark T.
Published: July 2005

Field observations indicate that a tidal salinity front that is regenerated each lower low water is a prominent feature of intertidal zone flow during wet winter months. A strong longitudinal density gradient at the front influences flow dynamics through tidal straining and baroclinic forcing. During each inundation period the salinity gradient disperses as it advects across the intertidal zone. The average longitudinal dispersivity estimated from observations is about 10 m2 s−1. A three‐dimensional numerical model yields comparable estimates of tidally averaged dispersivity for an idealized bathymetry with a subtidal channel and intertidal shoals. The instantaneous dispersivity through the tidal cycle depends on both vertical and lateral shear in along‐channel velocity. Dispersion due to vertical shear is greatest during stratified ebbs and inversely depends on tidal forcing; dispersion due to lateral shear results from bathymetric variability between channel and shoal and increases with tidal amplitude. Similarly, the along‐channel residual velocity is a combination of baroclinic and frictional processes. Frictional effects dominate the depth‐averaged residual such that net flow is upstream on the shoals and downstream in the channel; however, the frictional pattern is moderated by baroclinic forcing at the front. Although along‐channel dynamics dominate, differential advection of the salinity front establishes lateral baroclinic circulation between channel and shoals. Lateral residual circulation is flood dominant with dense water moving out of channel near the bed and convergence from the shoals at the surface. At times near the front the lateral salt flux can significantly affect the salinity budget in the channel.
Rosiglitazone and 15-deoxy-Δ12,14-prostaglandin J2 Cause Potent Neuroprotection after Experimental Stroke through Noncompletely Overlapping Mechanisms
Authors: Pereira Marta P , Hurtado Olivia , Cárdenas Antonio , Boscá Lisardo , Castillo José , Dávalos Antoni , Vivancos José , Serena Joaquín , Lorenzo Pedro , Lizasoain Ignacio , Moro María A
Published: July 2005

Stroke triggers an inflammatory cascade which contributes to a delayed cerebral damage, thus implying that antiinflammmatory strategies might be useful in the treatment of acute ischaemic stroke. Since two unrelated peroxisome proliferator-activated receptor-γ (PPARγ) agonists, the thiazolidinedione rosiglitazone (RSG) and the cyclopentenone prostaglandin 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), have been shown to possess antiinflammatory properties, we have tested their neuroprotective effects in experimental stroke. Rosiglitazone or 15d-PGJ2 were administered to rats 10 mins or 2 h after permanent middle cerebral artery occlusion (MCAO). Stroke outcome was evaluated by determination of infarct volume and assesment of neurological scores. Brains were collected for protein expression, gene array analyses and gene shift assays. Our results show that both compounds decrease MCAO-induced infarct size and improve neurological scores. At late times, the two compounds converge in the inhibition of MCAO-induced brain expression of inducible NO synthase and the matrix metalloproteinase 9. Interestingly, at early times, complementary DNA microarrays and gene shift assays show that different mechanisms are recruited. Analysis of early nuclear p65 and late cytosolic IκBα protein levels shows that both compounds inhibit nuclear factor-κB signalling, although at different levels. All these results suggest both PPARγ-dependent and independent pathways, and might be useful to design both therapeutic strategies and prognostic markers for stroke.
Brain Genomics of Intracerebral Hemorrhage
Authors: Lu Aigang , Tang Yang , Ran Ruiqiong , Ardizzone Timothy L , Wagner Kenneth R , Sharp Frank R
Published: July 2005

After intracerebral hemorrhage (ICH), many changes of gene transcription occur that may be important because they will contribute to understanding mechanisms of injury and recovery. Therefore, gene expression was assessed using Affymetrix microarrays in the striatum and the overlying cortex at 24 h after intracranial infusions of blood into the striatum of adult rats. Intracerebral hemorrhage regulated 369 of 8,740 transcripts as compared with saline-injected controls, with 104 regulated genes shared by the striatum and cortex. There were 108 upregulated and 126 downregulated genes in striatum, and 170 upregulated and 69 downregulated genes in the cortex. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed upregulation of IL-1-beta, Lipcortin 1 (annexin) and metallothionein 1,2, and downregulation of potassium voltage-gated channel, shaker-related subfamily, beta member 2 (Kcnab2). Of the functional groups of genes modulated by ICH, many metabolism and signal-transduction-related genes decreased in striatum but increased in adjacent cortex. In contrast, most enzyme, cytokine, chemokine, and immune response genes were upregulated in both striatum and in the cortex after ICH, likely in response to foreign proteins from the blood. A number of these genes may contribute to brain edema and cellular apoptosis caused by ICH. In addition, downregulation of growth factor pathways and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway could also contribute to perihematoma cell death/apoptosis. Intracerebral hemorrhage-related downregulation of GABA-related genes and potassium channels might contribute to perihematoma cellular excitability and increased risk of post-ICH seizures. These genomic responses to ICH potentially provide new therapeutic targets for treatment.
Regional Variation of Cerebral Blood Flow and Arterial Transit Time in the Normal and Hypoperfused Rat Brain Measured Using Continuous Arterial Spin Labeling MRI
Authors: Thomas David L , Lythgoe Mark F , van der Weerd Louise , Ordidge Roger J , Gadian David G
Published: July 2005

Continuous arterial spin labeling (CASL) is a noninvasive magnetic resonance (MR) method for measuring cerebral perfusion. In its most widely used form, CASL incorporates a postlabeling delay to minimize the sensitivity of the technique to transit time effects, which otherwise corrupt cerebral blood flow (CBF) quantification. For this delay to work effectively, it must be longer than the longest transit time present in the system. In this work, CASL measurements were made in four coronal slices in the rat brain using a range of postlabeling delays. By doing this, direct estimation of both CBF and arterial transit time (δa) was possible. These measurements were performed in the normal brain and during hypoperfusion induced by occlusion of the common carotid arteries. It was found that, in the normal rat brain, significant regional variation exists for both CBF and δa. Mean values of CBF and δa in the selected gray matter regions of interest were 233 mL/100 g min and 266 ms, respectively, with the latter ranging from 100 to 500 ms. Therefore, use of a 500-ms postlabeling delay is suitable for any location in the normal rat brain. After common carotid artery occlusion, CBF decreased and δa increased by regionally dependent amounts. In the sensory cortex, δa increased to a mean value of 740 ms, significantly greater than 500 ms. These results highlight the importance of either (a) determining δa as part of the CASL measurement or (b) knowing the approximate range of values δa is likely to take for a given application, so that the parameters of the CASL sequence can be chosen appropriately.
Theoretical and experimental studies of the infrared rovibrational spectrum of He2–N2O
Authors: Wang Xiao-Gang , Carrington Tucker , Tang Jian , McKellar A. R. W.
Published: July 2005

Rovibrational spectra of the He2–N2O complex in the ν1 fundamental band of N2O (2224cm−1) have been observed using a tunable infrared laser to probe a pulsed supersonic jet expansion, and calculated using five coordinates that specify the positions of the He atoms with respect to the NNO molecule, a product basis, and a Lanczos eigensolver. Vibrational dynamics of the complex are dominated by the torsional motion of the two He atoms on a ring encircling the N2O molecule. The resulting torsional states could be readily identified, and they are relatively uncoupled to other He motions up to at least υt=7. Good agreement between experiment and theory was obtained with only one adjustable parameter, the band origin. The calculated results were crucial in assigning many weaker observed transitions because the effective rotational constants depend strongly on the torsional state. The observed spectra had effective temperatures around 0.7 K and involved transitions with J⩽3, with υt=0 and 1, and (with one possible exception) with Δυt=0. Mixing of the torsion-rotation states is small but significant: some transitions with Δυt≠0 were predicted to have appreciable intensity even assuming that the dipole transition moment coincides perfectly with the NNO axis. One such transition was tentatively assigned in the observed spectra, but confirmation will require further work.
Nature of the entropy versus self-diffusivity plot for simple liquids
Authors: Kaur Charanbir , Harbola Upendra , Das Shankar P.
Published: July 2005

The empirical relation (D*)α=aexp[S] between the self-diffusion coefficient D* and the excess entropy S of a liquid is studied here in the context of theoretical model calculation. The coefficient α is dependent on the interaction potential and shows a crossover at an intermediate density, where cooperative dynamics become more important. Around this density a departure from the Stokes–Einstein relation is also observed. The above relation between entropy and diffusion is also tested for the scaled total diffusion coefficient in a binary mixture.
Relaxation dynamics in (HF)x(H2O)1−x solutions
Authors: Angelini R. , Giura P. , Monaco G. , Ruocco G. , Sette F.
Published: July 2005

The high-frequency dynamics of (HF)x(H2O)1−x solutions has been investigated by inelastic x-ray scattering. The measurements have been performed as a function of the concentration in the range x=0.20–0.73 at fixed temperature T=283K. The results have been compared with similar data in pure water (x=0) and pure hydrogen fluoride (x=1). A viscoelastic analysis of the data highlights the presence of a relaxation process characterized by a relaxation time and a strength directly related to the presence of a hydrogen-bond network in the system. The comparison with the data on water and hydrogen fluoride shows that the structural relaxation time continuously decreases at increasing concentration of hydrogen fluoride passing from the value for water to the one for hydrogen fluoride ταHF, which is three times smaller. This is the consequence of a gradual decreasing number of constraints of the hydrogen-bond networks in passing from one liquid to the other.
Potential of mean force between two nanometer-scale particles in a polymer solution
Authors: Doxastakis M. , Chen Y.-L. , de Pablo J. J.
Published: July 2005

Expanded ensemble density-of-states simulations and a connectivity altering algorithm are used to investigate the effective interactions that arise between nanoparticles suspended in polymer solutions. Our calculations with systems of long polymeric chains reveal oscillations in the effective polymer-induced interactions between the particles, even at low concentrations. The range of these interactions is considerably longer than originally anticipated, and their origin is traced back to the chain-end effects and density fluctuations that were absent in previous treatments of these systems.
Quantitative molecular thermochemistry based on path integrals
Authors: Glaesemann Kurt R. , Fried Laurence E.
Published: July 2005

The calculation of thermochemical data requires accurate molecular energies and heat capacities. Traditional methods rely upon the standard harmonic normal-mode analysis to calculate the vibrational and rotational contributions. We utilize path-integral Monte Carlo for going beyond the harmonic analysis and to calculate the vibrational and rotational contributions to ab initio energies. This is an application and an extension of a method previously developed in our group [J. Chem. Phys. 118, 1596 (2003)].
Nonbroadened asymmetric waveguide diode lasers promise much narrower far fields than broadened symmetric waveguide ones
Authors: Ryvkin B. S. , Avrutin E. A.
Published: July 2005

We show that a semiconductor laser with an asymmetric, relatively narrow waveguide can be expected to have a considerably narrower transverse far-field profile than that achieved with a broadened symmetric waveguide with the same equivalent spot size, resulting in a more efficient input of light into a given numerical aperture.
Zn-doped GaSb epitaxial film absorption coefficients at terahertz frequencies and detector applications
Authors: Hu Z. G. , Perera A. G. U. , Paltiel Y. , Raizman A. , Sher A.
Published: July 2005

The reflectance measurements of p-type GaSb:Zn epitaxial films with different hole concentrations, grown by metalorganic vapor-phase epitaxy, have been investigated in the 3–30-THz frequency region. The experimental spectra were fitted using a classical harmonic Lorentz oscillator and the Drude model, illustrating that the hole effective mass and the mobility change with the carrier concentration. The hole effective mass was found to vary from 0.22m0 to 0.41m0 as the carrier concentration changed from 3.5×1017 to 3.8×1018cm−3. The mobility values derived from the reflectance measurements were slightly smaller than the values obtained from Hall-effect measurements. A sublinear relationship between the absorption coefficient and the hole concentration was found at a frequency of 3 THz. Those results can be used for designing GaSb-based terahertz detectors.
Doping of spray-pyrolyzed ZnO thin films through direct diffusion of indium: Structural optical and electrical studies
Authors: Ratheesh Kumar P. M. , Kartha C. Sudha , Vijayakumar K. P.
Published: July 2005

Effect of thermal diffusion of indium in ZnO thin films, prepared using spray pyrolysis technique, is discussed. ZnO:In films were characterized using different techniques such as x-ray diffraction (XRD), photoluminescence, electrical resistivity measurements, and optical absorption and transmission. The XRD analysis showed that all the films had a preferred (002) orientation. There was no considerable change in peak height or full width at half maximum, due to the variation in doping percentage. Peak positions corresponding to (002) and (101) planes were slightly shifted to lower 2θ values. Optical band gap also decreased slightly with indium concentration, and for higher indium concentration percentage of transmission reduced very much. Drastic decrease in resistivity was observed and two activation energies (30 and 15meV) were obtained for the doped samples. These levels were identified as due to zinc interstitials and/or due to indium at zinc lattice and impurity related defect levels. Photoluminescence measurements gave two emissions. In this, one was the near band-edge (NBE) emission and the other was the blue-green emission. As doping concentration increased, the NBE emission shifted to higher wavelength while the blue-green emission was shifted to lower wavelength (blueshift).
New suspension system for the gravitational wave bar detector AURIGA
Authors: Bignotto Michele , Bonaldi Michele , Cerdonio Massimo , Conti Livia , Penasa Francesco , Prodi Giovanni A. , Soranzo Gabriele , Taffarello Luca , Zendri Jean-Pierre
Published: July 2005

We report on the design of the new suspension system for the gravitational wave bar detector AURIGA. The system was designed with the aid of finite element modeling simulations with the goal of achieving at least −240dB of vibration reduction at 900Hz in a cryogenic environment, while preserving a high mechanical quality factor. We report room temperature measurements of the suspension core stage, mode frequencies, and attenuation and we discuss them on the basis of the simulation predictions. The suspension system is currently installed in the detector, which is properly working at the operating temperature of 4.2K. The observed improvements related to the suspension design are reported and discussed.
Fiber-optic based method for the measurements of electric-field induced displacements in ferroelectric materials
Authors: Vyshatko Nikolai P. , Brioso Paulo M. , de la Cruz Javier Pérez , Vilarinho Paula M. , Kholkin Andrei L.
Published: July 2005

A novel technique for the measurements of electric field-induced displacements in ferroelectric materials is presented. The method relies on a high sensitivity of the fiber-optic probe (Fotonic Sensor™, MTI Inc.) that measures the displacement of a specially designed cantilever beam having both electrical and mechanical contact with deforming sample. In this way, the major disadvantages of the standard Fotonic Sensor technique can be avoided. The method provides relatively high sensitivity (down to ∼4Å), high stability (7% over 8h), and sufficiently broad frequency range. The capabilities of the proposed measurement setup are validated by the strain measurements in bulk Pb(Zr,Ti)O3(PZT) ceramics and thin films.
Reciprocal space mapping by spot profile analyzing low energy electron diffraction
Authors: Meyer zu Heringdorf Frank-J. , Horn-von Hoegen Michael
Published: July 2005

We present an experimental approach for the recording of two-dimensional reciprocal space maps using spot profile analyzing low energy electron diffraction (SPA-LEED). A specialized alignment procedure eliminates the shifting of LEED patterns on the screen which is commonly observed upon variation of the electron energy. After the alignment, a set of one-dimensional sections through the diffraction pattern is recorded at different energies. A freely available software tool is used to assemble the sections into a reciprocal space map. The necessary modifications of the Burr-Brown computer interface of the two Leybold and Omicron type SPA-LEED instruments are discussed and step-by-step instructions are given to adapt the SPA 4.1d software to the changed hardware. Au induced faceting of 4° vicinal Si(001) is used as an example to demonstrate the technique.
Kinetic theory of partially ionized complex (dusty) plasmas
Authors: Tsytovich V. N. , de Angelis U. , Ivlev A. V. , Morfill G. E.
Published: July 2005

The general approach to the kinetic theory of complex (dusty) plasmas [Tsytovich and de Angelis, Phys. Plasmas 6, 1093 (1999)], which was formulated with the assumption of a regular (nonfluctuating) source of plasma particles, is reformulated to include ionization by electron impact on neutrals as the plasma source and the effects of collisions of ions and dust particles with neutrals.
Plasma density behavior with new graphite limiters in the Hefei Tokamak-7
Authors: Asif M. , Gao X. , Li J. , Kuang G. L. , Wan B. N. , Jie Y. X. , Zhao J. Y. , Zhang X. D. , Liu H. Q. , Tong X. D. , Liu J. , Xu Q. , Hu J. S. , Yang Y. , Shen B. , Mao J. S. , Hu L. Q. , Wu Z. W. , Ling B. L. ,   the HT-7 Team
Published: July 2005

A new set of actively cooled toroidal double-ring graphite limiters has been developed in the Hefei Tokamak-7 (HT-7) [X. Gao et al., Phys. Plasmas 7, 2933 (2000)] for long pulse operation. The extension of operational region and density behavior with graphite (C) limiters have been studied in this paper. Extended high-density region at the high plasma current low-qa was obtained. The density profile with the C limiter was studied to compare with the previous molybdenum (Mo) limiter. The critical density of multifaceted asymmetric radiation from the edge (MARFE) onset is observed in the region of Zeff1∕2fGW=0.9∼1.2, where fGW=n¯e∕nGW. (Here n¯e is the maximum line average electron density and nGW is the Greenwald density.) Under the same injected power, the critical density of MARFE onset with the new C limiter is much higher than the previous Mo limiter.
Ultrasensitive mass sensor fully integrated with complementary metal-oxide-semiconductor circuitry
Authors: Forsen E. , Abadal G. , Ghatnekar-Nilsson S. , Teva J. , Verd J. , Sandberg R. , Svendsen W. , Perez-Murano F. , Esteve J. , Figueras E. , Campabadal F. , Montelius L. , Barniol N. , Boisen A.
Published: July 2005

Nanomechanical resonators have been monolithically integrated on preprocessed complementary metal-oxide-semiconductor (CMOS) chips. Fabricated resonator systems have been designed to have resonance frequencies up to 1.5 MHz. The systems have been characterized in ambient air and vacuum conditions and display ultrasensitive mass detection in air. A mass sensitivity of 4ag∕Hz has been determined in air by placing a single glycerine drop, having a measured weight of 57 fg, at the apex of a cantilever and subsequently measuring a frequency shift of 14.8 kHz. CMOS integration enables electrostatic excitation, capacitive detection, and amplification of the resonance signal directly on the chip.
Optical properties and carrier dynamics of two-dimensional electrons in AlGaN∕GaN single heterostructures
Authors: Kwack Ho-Sang , Cho Yong-Hoon , Kim G. H. , Park M. R. , Youn D. H. , Bae S. B. , Lee K.-S. , Lee Jae-Hoon , Lee Jung-Hee , Kim T. W. , Kang T. W. , Wang Kang L.
Published: July 2005

We have investigated the optical properties and carrier dynamics of the two-dimensional electron gas (2DEG) in Al0.4Ga0.6N∕GaN single heterostructures grown by metalorganic chemical vapor deposition by means of photoluminescence (PL), PL excitation, and time-resolved PL spectroscopy. Shubnikov-de Haas oscillations were clearly observed at 1.5K, confirming the existence of a 2DEG. An additional 2DEG PL emission appeared at about 40meV below the GaN band-edge emission and persisted up to about 100K, while this peak disappeared when the top Al0.4Ga0.6N layer was removed by reactive ion etching. We observed abrupt PLE absorption at GaN band edge energy and approximately 50-ps delayed risetime compared to GaN and AlGaN emissions, indicating effective carrier transfer from the GaN flatband and AlGaN regions to the heterointerface. Even though the 2DEG emission is a spatially-indirect (slow) recombination, a fast decay component of ∼0.2ns is found to be dominant in 2DEG emission because of the fast exhaustion of photogenerated holes in GaN flatband region via spatially-direct (fast) GaN recombination. From the results, we explain the carrier generation, transfer, and recombination dynamics and the relationships between 2DEG, GaN, and Al0.4Ga0.6N emissions in undoped Al0.4Ga0.6N∕GaN single heterostructures.
Recognition of a subregion of human proinsulin by class I-restricted T cells in type 1 diabetic patients
Authors: Toma Andréa , Haddouk Samy , Briand Jean-Paul , Camoin Luc , Gahery Hanne , Connan Francine , Dubois-Laforgue Danielle , Caillat-Zucman Sophie , Guillet Jean-Gérard , Carel Jean-Claude , Muller Sylviane , Choppin Jeannine , Boitard Christian
Published: July 2005

Proinsulin is a key autoantigen in type 1 diabetes. Evidence in the mouse has underscored the importance of the insulin B chain region in autoimmunity to pancreatic beta cells. In man, a majority of proteasome cleavage sites are predicted by proteasome cleavage algorithms within this region. To study CD8+T cell responses to the insulin B chain and adjacent C peptide, we selected 8- to 11-mer peptides according to proteasome cleavage patterns obtained by digestion of two peptides covering proinsulin residues 28 to 64. We studied their binding to purified HLA class I molecules and their recognition by T cells from diabetic patients. Peripheral blood mononuclear cells from 17 of 19 recent-onset and 12 of 13 long-standing type 1 diabetic patients produced IFN-γ in response to proinsulin peptides as shown by using an ELISPOT assay. In most patients, the response was against several class I-restricted peptides. Nine peptides were recognized within the proinsulin region covering residues 34 to 61. Four yielded a high frequency of recognition in HLA-A1 and -B8 patients. Three peptides located in the proinsulin region 41–51 were shown to bind several HLA molecules and to be recognized in a high percentage of diabetic patients.