bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of Aura Microwave Limb Sounder Ozone by ozonesonde and lidar measurements
Authors: Jiang Y. B. , Froidevaux L. , Lambert A. , Livesey N. J. , Read W. G. , Waters J. W. , Bojkov B. , Leblanc T. , McDermid I. S. , Godin‐Beekmann S. , Filipiak M. J. , Harwood R. S. , Fuller R. A. , Daffer W. H. , Drouin B. J. , Cofield R. E. , Cuddy D. T. , Jarnot R. F. , Knosp B. W. , Perun V. S. , Schwartz M. J. , Snyder W. V. , Stek P. C. , Thurstans R. P. , Wagner P. A. , Allaart M. , Andersen S. B. , Bodeker G. , Calpini B. , Claude H. , Coetzee G. , Davies J. , De Backer H. , Dier H. , Fujiwara M. , Johnson B. , Kelder H. , Leme N. P. , König‐Langlo G. , Kyro E. , Laneve G. , Fook L. S. , Merrill J. , Morris G. , Newchurch M. , Oltmans S. , Parrondos M. C. , Posny F. , Schmidlin F. , Skrivankova P. , Stubi R. , Tarasick D. , Thompson A. , Thouret V. , Viatte P. , Vömel H. , von Der Gathen P. , Yela M. , Zablocki G.
Published: December 2007

We present validation studies of MLS version 2.2 upper tropospheric and stratospheric ozone profiles using ozonesonde and lidar data as well as climatological data. Ozone measurements from over 60 ozonesonde stations worldwide and three lidar stations are compared with coincident MLS data. The MLS ozone stratospheric data between 150 and 3 hPa agree well with ozonesonde measurements, within 8% for the global average. MLS values at 215 hPa are biased high compared to ozonesondes by ∼20% at middle to high latitude, although there is a lot of variability in this altitude region. Comparisons between MLS and ground‐based lidar measurements from Mauna Loa, Hawaii, from the Table Mountain Facility, California, and from the Observatoire de Haute‐Provence, France, give very good agreement, within ∼5%, for the stratospheric values. The comparisons between MLS and the Table Mountain Facility tropospheric ozone lidar show that MLS data are biased high by ∼30% at 215 hPa, consistent with that indicated by the ozonesonde data. We obtain better global average agreement between MLS and ozonesonde partial column values down to 215 hPa, although the average MLS values at low to middle latitudes are higher than the ozonesonde values by up to a few percent. MLS v2.2 ozone data agree better than the MLS v1.5 data with ozonesonde and lidar measurements. MLS tropical data show the wave one longitudinal pattern in the upper troposphere, with similarities to the average distribution from ozonesondes. High upper tropospheric ozone values are also observed by MLS in the tropical Pacific from June to November.
The Meaning of the Future: Toward a More Specific Definition of Possible Selves
Authors: Erikson Martin G.
Published: December 2007

Possible selves are traditionally defined as conceptions of our selves in future states. The author discusses the way the theory is used in the literature and argues that there is a need for a clearer definition, because there appear to be a number of common misinterpretations regarding possible selves. Important features of possible selves are discussed, in particular their nature as experienced meaning, their relation with the rest of the self-concept, and their social and cultural nature. It is suggested that agency is an important aspect of possible selves and that they can be seen as narratives. The clearer definition suggested is that possible selves are conceptions of our selves in the future, including, at least to some degree, an experience of being an agent in a future situation. Possible selves get vital parts of their meaning in interplay with the self-concept, which they in turn moderate, as well as from their social and cultural context.
Sildenafil reduces alcohol‐induced gastric damage: just say ‘NO’
Authors: Duffin R , Shaw C A , Rossi A G
Published: December 2007

Although sildenafil (Viagra) and other phosphodiesterase V (PDE V) inhibitors are increasingly recognized for their use in the treatment of male erectile dysfunction and perhaps more recently pulmonary artery hypertension, less is known of their potential beneficial effects in other situations. Medeiros et al., in the current issue of the British Journal of Pharmacology, report that sildenafil dramatically reduces alcohol‐induced gastric damage in rats. The authors provide convincing evidence that such protection not only occurs via the nitric oxide (NO)/cGMP pathway, but also involves regulation of ATP‐sensitive potassium channels. Therefore, in addition to exerting anti‐impotence efficacy, PDE V inhibitors may provide significant beneficial effects from mucosal injury induced by alcohol.

British Journal of Pharmacology (2008) 153, 623–624; doi:10.1038/sj.bjp.0707642; published online 17 December 2007
Vibronic transitions in large molecular systems: Rigorous prescreening conditions for Franck-Condon factors
Authors: Jankowiak H.-C. , Stuber J. L. , Berger R.
Published: December 2007

In this work, rigorous prescreening conditions for the calculation of Franck-Condon factors (FCFs) are derived and implemented. These factors play an important role in numerous applications including the prediction and simulation of vibronic spectra, electron transfer rates, and nonradiative transition probabilities. For larger systems it is crucial to calculate only relevant FCFs, as the computational burden becomes otherwise prohibitive due to the sheer number of Franck-Condon integrals. By exploiting rigorous prescreening criteria one can significantly reduce the computational effort and systematically refine results to the desired target accuracy. In this work, such criteria are derived via the use of sum rules obtained through a coherent state generating function for the FCFs in the harmonic oscillator approximation, following the prescription of Doktorov et al. These sum rules allow efficient and rigorous prescreening prior to the calculation of entire batches of Franck-Condon integrals, reducing the subsequent computational burden. To illustrate the benefit of employing such conditions, they are applied in this work to calculate FC profiles for vibronic spectra of formic acid, thymine, anthracene, and a polycyclic aromatic hydrocarbon derivative containing about 450 vibrational degrees of freedom. Since the prescreening step gives stringent upper and lower bounds for the loss of FC intensity in these spectra arising from the neglected FCFs, the present approach renders most previous a priori selection schemes obsolete and has the potential to complement or even replace other approximate treatments.
Energy level structure and electron relaxation times in InAs∕InxGa1−xAs quantum dot-in-a-well structures
Authors: Aivaliotis P. , Menzel S. , Zibik E. A. , Cockburn J. W. , Wilson L. R. , Hopkinson M.
Published: December 2007

Complementary interband and intraband optical spectroscopic techniques are used to investigate the band structure and carrier relaxation times in technologically important InAs∕InGaAs∕GaAs quantum dot-in-a-well (DWELL) structures. We determine the dot ground to first excited state energies to be 42meV in the conduction band and 18meV in the valence band. Using intraband pump-probe experiments, electron relaxation times from the well states to the dot ground state are measured to be ∼5ps at 10K. Our results provide important parameters for the design and simulation of DWELL-based interband lasers and intraband midinfrared photodetectors.
A series of layered intergrowth phases grown by molecular beam epitaxy: SrmTiO2+m(m=1–5)
Authors: Fisher P. , Wang S. , Skowronski M. , Salvador P. A. , Snyder M. , Maksimov O.
Published: December 2007

Sr m Ti O 2 + m phases having one TiO2 layer sandwiched between m SrO layers were grown using molecular beam epitaxy. The out-of-plane (in-plane) lattice parameters determined by x-ray diffraction were c(a)=9.14Å (3.78Å), 23.55Å (3.75Å), and 14.60Å (3.75Å) for Sr3TiO5, Sr4TiO6, and Sr5TiO7, respectively. Both lattice parameters change abruptly on going from the m=2 Ruddlesden-Popper phase to m=3 phase, indicating a significant change in the bond lengths (or strain states) on transitioning from the known members to the higher order members of this structural family. Electron microscopy confirmed the artificially layered structures.
Low leakage current gate dielectrics prepared by ion beam assisted deposition for organic thin film transistors
Authors: Kim Chang Su , Jo Sung Jin , Kim Jong Bok , Ryu Seung Yoon , Noh Joo Hyon , Baik Hong Koo , Lee Se Jong , Kim Youn Sang
Published: December 2007

This communication reports on the fabrication of low operating voltage pentacene thin-film transistors with high-k gate dielectrics by ion beam assisted deposition (IBAD). These densely packed dielectric layers by IBAD show a much lower level of leakage current than those created by e-beam evaporation. These results, from the fact that those thin films deposited with low adatom mobility, have an open structure, consisting of spherical grains with pores in between, that acts as a significant path for leakage current. By contrast, our results demonstrate the potential to limit this leakage. The field effect mobility, on/off current ratio, and subthreshold slope obtained from pentacene thin-film transistors (TFTs) were 1.14 cm2/V s, 105, and 0.41 V/dec, respectively. Thus, the high-k gate dielectrics obtained by IBAD show promise in realizing low leakage current, low voltage, and high mobility pentacene TFTs.
Ferroelectric and dielectric behavior of heterolayered PZT thin films
Authors: Kartawidjaja F. C. , Sim C. H. , Wang J.
Published: December 2007

Heterolayered Pb(Zr1−xTix)O3 thin films consisting of different numbers of alternating Pb(Zr0.7Ti0.3)O3 and Pb(Zr0.3Ti0.7)O3 layers are studied. They exhibit (001)∕(100) preferred orientation and dense microstructure when baked at 500°C and then thermally annealed at 650°C. They demonstrate a considerably low leakage current density in the order of 10−7A∕cm2. Their ferroelectric and dielectric properties are improved with increasing number of alternating Pb(Zr0.7Ti0.3)O3 and Pb(Zr0.3Ti0.7)O3 layers, thereby the six-heterolayered PZT thin film shows a much enhanced remanent polarization of 41.3μC∕cm2 and relative permittivity of 710 at 1kHz. In fatigue test, a wake-up phenomenon is observed with the heterolayered films, where the degradation in switchable polarization is delayed. At elevated temperatures, the wake-up phenomenon was reduced, leading to fatigue degradation at a relatively lower number of switching cycles. The phenomenon is related to the injected electron causing oxygen vacancies, the accumulation of which impedes the domain switching.
Direction-dependent spontaneous emission from near-infrared quantum dots at the angular band edges of a three-dimensional photonic crystal
Authors: Li Jiafang , Jia Baohua , Zhou Guangyong , Gu Min
Published: December 2007

Engineering spontaneous emission from light emitters embedded within three-dimensional photonic crystals is of great significance in both fundamental research of quantum optics and applications of microphotonic devices. In this letter, we report on the effective modification of spontaneous emission from near-infrared PbSe quantum dots infiltrated in a three-dimensional woodpile polymeric photonic crystal through adjusting its angle-dependent stop gaps. A significant inhibition effect as well as a pronounced enhancement of the spontaneous emission are observed in the midgap and at the center of the band edge, respectively. The observed phenomenon can be understood from the stretched exponential model on decay dynamics.
Gentle imaging of soft materials in solution with amplitude modulation atomic force microscopy: Q control and thermal noise
Authors: Ashby Paul D.
Published: December 2007

Increasing the effective Q factor using feedback (Q control) decreases tip-sample interaction forces for amplitude modulation atomic force microscopy. However, the feedback loop amplifies thermal noise compromising the signal to noise ratio. Simulations, which include thermal excitations, reveal that average tip-sample forces scaled for signal to noise ratio remain roughly unchanged as Q factor changes for intrinsically low Q environments such as liquids. Furthermore, increased Q causes the tip-sample interaction to become sporadic and hinders consistent imaging. Thus, it is preferable to image with small amplitudes instead of higher effective Q factor.
Valence band structures of the phase change material Ge2Sb2Te5
Authors: Lee Dohyun , Lee Sang Sun , Kim Wondong , Hwang Chanyong , Hossain M. B. , Hung Ngyuen Le , Kim Hyojin , Kim C. G. , Lee Hangil , Hwang Han Na , Hwang Chan-Cuk , Lee Tae-Yon , Kang Younseon , Kim Cheolkyu , Suh Dong-Seok , Kim Kijoon H. P. , Khang Yoonho
Published: December 2007

We report the experimental evidence of significant change of the valence band structure during crystallization of Ge2Sb2Te5 (GST). Amorphous GST, prepared by sputter deposition at room temperature (RT), transforms successively into face-centered-cubic (fcc) and a hexagonal-close-packed (hcp) structures at around 150 and 300°C, respectively, during a stepwise temperature increase from RT to 350°C. During temperature increase, ultraviolet photoemission spectra were in vacuo obtained using synchrotron radiation. The measurement of the amorphous and fcc GST shows that the difference between the maximum valence band edge and the Fermi level reduces by 0.35eV during crystallization. For the fcc to hcp phase transformation, no band gap reduction was observed.
Herbicide use, productivity, and nitrogen fixation in field pea (Pisum sativum)
Authors: Drew E. A. , Gupta V. V. S. R. , Roget D. K.
Published: December 2007

Grain legumes grown in low-rainfall (<300 mm per annum) cropping regions of southern Australia have at times failed to provide the rotational benefits observed in other regions, such as improved cereal yields in the season following a legume. ‘In-crop’ herbicides were identified as one possible factor that may have been negatively affecting the legume–rhizobia symbiosis. To test this hypothesis and identify possible mechanisms behind any observed effects, field trials were conducted at Waikerie (South Australia) in 2001, 2003, and 2004. Field pea (Pisum sativum L.) was grown and treated with one of several herbicides 5 weeks after sowing. Crop yellowing, biomass, nodulation, and nitrogen (N2) fixation were assessed 3 weeks after spraying, and biomass, yield, percent nitrogen derived from fixation (%Ndfa), and N2 fixation (2003, 2004) were assessed at the end of the season. Some herbicides stunted plant growth and caused crop yellowing 3 weeks after application; however, none of the herbicides affected N nutrition of peas. Despite this, in 2003, half of the herbicides assessed reduced the %Ndfa by 34–60% relative to unsprayed control plots. Herbicide effects on the measured parameters followed similar trends over each year of the 3-year study. However, effects were rarely significant in 2004 as the trials were primarily affected by low rainfall, indicating that environmental parameters play a key role in determining the severity of herbicide effects on symbiotic N2 fixation. The possible mechanisms behind herbicide-induced damage to the pea–rhizobium symbiosis are discussed, including reduced photosynthetic capacity of plants exposed to herbicides.
An evaluation of the tactical use of lucerne phase farming to reduce deep drainage
Authors: Verburg K. , Bond W. J. , Brennan L. E. , Robertson M. J.
Published: December 2007

Lucerne phase farming has been suggested as a way of reducing deep drainage in the cereal belt of southern Australia. It is based on the concept that lucerne (Medicago sativa L.), a perennial pasture with a deep root system, creates a soil water storage buffer below the root zone of the annual crops, which gradually refills during the subsequent cropping phase, temporarily reducing the risk of deep drainage. The rate of refilling is variable because it is affected by the amount and distribution of rainfall as well as management of the crop and the summer fallow. There is, therefore, uncertainty about the optimum phase durations that will maximise the effect of the lucerne phase.
Computer simulations were applied to evaluate the use of a soil water measurement below the root zone of annual crops to schedule the phase changes, referred to as tactical phase farming. The results confirmed that phase farming reduced average annual deep drainage significantly, but at the cost of lower average annual gross margin. In most cases, tactical phase farming improved the trade-off between deep drainage and gross margin relative to fixed duration phases; for a given amount of average annual deep drainage the average annual gross margin was larger, and for a given gross margin the drainage was smaller. The benefits of tactical phase systems were greatest in soils with a large available water-holding capacity and when the variability of the refilling rate was large. Overall, however, the benefits of the tactical approach relative to fixed phase systems were small.
Fast Algorithms for Matching CCD Images to a Stellar Catalogue
Authors: Tabur V.
Published: December 2007

Two new algorithms are described for matching two dimensional coordinate lists of point sources that are significantly faster than previous methods. By matching rarely occurring triangles (or more complex shapes) in the two lists, and by ordering searches by decreasing probability of success, it is demonstrated that very few candidates need be considered to find a successful match. Moreover, by immediately testing the suitability of a potential match using an efficient mechanism, the need to process the entire candidate set is avoided, yielding considerable performance improvements. Triangles are described by a cosine metric that reduces the density of triangle space, permitting efficient searches. An alternative shape characterization method that reduces computational overhead in the construction phase is discussed. The algorithms are tested on a set of 10 063 wide-field survey images, with fields-of-view up to 4.8° × 3.6°, successfully matching 100% of the images in a mean elapsed time of 6 ms (2.4 GHz Athlon CPU). The elapsed time of the searching phase is shown to vary by less than 1ms for list sizes between 10 and 200 points, demonstrating that fast, robust searches may be completed in nearly constant time, independent of list size.
Restoration treatments enhance early establishment of native forbs in a degraded temperate grassy woodland
Authors: Smallbone Lisa T. , Prober Suzanne M. , Lunt Ian D.
Published: December 2007

We investigated effects of three understorey restoration treatments, carbon (sugar) addition, spring burning and re-establishment of the perennial native grass Themeda australis (R.Br.) Stapf, on early establishment of eight species of native forbs in a degraded white box (Eucalyptus albens Benth.) woodland dominated by exotic annuals, in central New South Wales, Australia. Forb seeds and seedlings were introduced to treatments in a randomised, irrigated field trial and monitored for 4–8 months. Treatments significantly altered vegetation structure and composition, resulting in higher native grass and lower exotic grass cover on sugar and burnt plots (especially if seeded with Themeda), a proliferation of broadleaf exotic annuals on burnt plots, and continued high cover of exotic annual grasses and broadleaf annuals on control plots. Forb germination was largely confined to three large-seeded forbs, Bulbine bulbosa (R.Br.) Haw., Dichopogon fimbriatus (R.Br.) J.F.Macbr. and Microseris lanceolata (Walp.) Schultz-Bip., and few germinants of three small-seeded forbs were observed. Overall, germination (% emergence, and seedling numbers after 4 months) was significantly greater on sugar than burnt and control plots, while transplant survival was significantly enhanced by both sugar and burning treatments for up to 8 months after planting. Re-introduced Themeda swards significantly promoted seedling germination and transplant survival in burnt plots. While long-term seedling survival was extremely low owing to severe drought, we concluded that (i) the applied restoration treatments (especially carbon addition) have considerable potential for promoting forb establishment in degraded woodlands, (ii) reduced competition with exotic annuals associated with carbon addition outweighed potential disadvantages of reduced nutrient levels, (iii) competition with broadleaf annuals and/or exposure to more extreme environments associated with burning may be problematic for forb germination and (iv) Themeda swards may be more conducive to establishment of native forbs than swards of exotic annuals, owing to their contrasting growth strategies.
Cdk2 is critical for proliferation and self-renewal of neural progenitor cells in the adult subventricular zone
Authors: Jablonska Beata , Aguirre Adan , Vandenbosch Renaud , Belachew Shibeshih , Berthet Cyril , Kaldis Philipp , Gallo Vittorio
Published: December 2007

We investigated the function of cyclin-dependent kinase 2 (Cdk2) in neural progenitor cells during postnatal development. Chondroitin sulfate proteoglycan (NG2)–expressing progenitor cells of the subventricular zone (SVZ) show no significant difference in density and proliferation between Cdk2−/− and wild-type mice at perinatal ages and are reduced only in adult Cdk2−/− mice. Adult Cdk2−/− SVZ cells in culture display decreased self-renewal capacity and enhanced differentiation. Compensatory mechanisms in perinatal Cdk2−/− SVZ cells, which persist until postnatal day 15, involve increased Cdk4 expression that results in retinoblastoma protein inactivation. A subsequent decline in Cdk4 activity to wild-type levels in postnatal day 28 Cdk2−/− cells coincides with lower NG2+ proliferation and self-renewal capacity similar to adult levels. Cdk4 silencing in perinatal Cdk2−/− SVZ cells abolishes Cdk4 up-regulation and reduces cell proliferation and self- renewal to adult levels. Conversely, Cdk4 overexpression in adult SVZ cells restores proliferative capacity to wild-type levels. Thus, although Cdk2 is functionally redundant in perinatal SVZ, it is important for adult progenitor cell proliferation and self-renewal through age-dependent regulation of Cdk4.
A naturally occurring calcineurin variant inhibits FoxO activity and enhances skeletal muscle regeneration
Authors: Lara-Pezzi Enrique , Winn Nadine , Paul Angelika , McCullagh Karl , Slominsky Esfir , Santini Maria Paola , Mourkioti Foteini , Sarathchandra Padmini , Fukushima Satsuki , Suzuki Ken , Rosenthal Nadia
Published: December 2007

The calcium-activated phosphatase calcineurin (Cn) transduces physiological signals through intracellular pathways to influence the expression of specific genes. Here, we characterize a naturally occurring splicing variant of the CnAβ catalytic subunit (CnAβ1) in which the autoinhibitory domain that controls enzyme activation is replaced with a unique C-terminal region. The CnAβ1 enzyme is constitutively active and dephosphorylates its NFAT target in a cyclosporine-resistant manner. CnAβ1 is highly expressed in proliferating myoblasts and regenerating skeletal muscle fibers. In myoblasts, CnAβ1 knockdown activates FoxO-regulated genes, reduces proliferation, and induces myoblast differentiation. Conversely, CnAβ1 overexpression inhibits FoxO and prevents myotube atrophy. Supplemental CnAβ1 transgene expression in skeletal muscle leads to enhanced regeneration, reduced scar formation, and accelerated resolution of inflammation. This unique mode of action distinguishes the CnAβ1 isoform as a candidate for interventional strategies in muscle wasting treatment.
Interaction of the conserved oligomeric Golgi complex with t-SNARE Syntaxin5a/Sed5 enhances intra-Golgi SNARE complex stability
Authors: Shestakova Anna , Suvorova Elena , Pavliv Oleksandra , Khaidakova Galimat , Lupashin Vladimir
Published: December 2007

Tethering factors mediate initial interaction of transport vesicles with target membranes. Soluble N-ethylmaleimide–sensitive fusion protein attachment protein receptors (SNAREs) enable consequent docking and membrane fusion. We demonstrate that the vesicle tether conserved oligomeric Golgi (COG) complex colocalizes and coimmunoprecipitates with intra-Golgi SNARE molecules. In yeast cells, the COG complex preferentially interacts with the SNARE complexes containing yeast Golgi target (t)-SNARE Sed5p. In mammalian cells, hCog4p and hCog6p interact with Syntaxin5a, the mammalian homologue of Sed5p. Moreover, fluorescence resonance energy transfer reveals an in vivo interaction between Syntaxin5a and the COG complex. Knockdown of the mammalian COG complex decreases Golgi SNARE mobility, produces an accumulation of free Syntaxin5, and decreases the steady-state levels of the intra-Golgi SNARE complex. Finally, overexpression of the hCog4p N-terminal Syntaxin5a-binding domain destabilizes intra-Golgi SNARE complexes, disrupting the Golgi. These data suggest that the COG complex orchestrates vesicular trafficking similarly in yeast and mammalian cells by binding to the t-SNARE Syntaxin5a/Sed5p and enhancing the stability of intra-Golgi SNARE complexes.
PDZRhoGEF and myosin II localize RhoA activity to the back of polarizing neutrophil-like cells
Authors: Wong Kit , Van Keymeulen Alexandra , Bourne Henry R.
Published: December 2007

Chemoattractants such as formyl-Met-Leu-Phe (fMLP) induce neutrophils to polarize by triggering divergent pathways that promote formation of a protrusive front and contracting back and sides. RhoA, a Rho GTPase, stimulates assembly of actomyosin contractile complexes at the sides and back. We show here, in differentiated HL60 cells, that PDZRhoGEF (PRG), a guanine nucleotide exchange factor (GEF) for RhoA, mediates RhoA-dependent responses and determines their spatial distribution. As with RNAi knock-down of PRG, a GEF-deleted PRG mutant blocks fMLP-dependent RhoA activation and causes neutrophils to exhibit multiple fronts and long tails. Similarly, inhibition of RhoA, a Rho-dependent protein kinase (ROCK), or myosin II produces the same morphologies. PRG inhibition reduces or mislocalizes monophosphorylated myosin light chains in fMLP-stimulated cells, and myosin II ATPase inhibition reciprocally disrupts normal localization of PRG. We propose a cooperative reinforcing mechanism at the back of cells, in which PRG, RhoA, ROCK, myosin II, and actomyosin spatially cooperate to consolidate attractant-induced contractility and ensure robust cell polarity.
The role of the nucleus basalis magnocellularis in fear conditioning consolidation in the rat
Authors: Baldi Elisabetta , Mariottini Chiara , Bucherelli Corrado
Published: December 2007

The nucleus basalis magnocellularis (NBM) is known to be involved in the memorization of several conditioned responses. To investigate the role of the NBM in fear conditioning memorization, this neural site was subjected to fully reversible tetrodotoxin (TTX) inactivation during consolidation in adult male Wistar rats that had undergone fear training to acoustic conditioned stimulus (CS) and context. TTX was stereotaxically administered to different groups of rats at increasing intervals after the acquisition session. Memory was assessed as the conditioned freezing duration measured during retention testing, always performed 72 and 96 h after TTX administration. In this way, there was no interference with normal NBM function during either acquisition or retrieval phases, allowing any amnesic effect to be due only to consolidation disruption. The results show that for contextual fear response memory consolidation, NBM functional integrity is necessary up to 24 h post-acquisition. On the other hand, NBM functional integrity was shown to be necessary for memory consolidation of the acoustic CS fear response only immediately after acquisition and not 24-h post-acquisition. The present findings help to elucidate the role of the NBM in memory consolidation and better define the neural circuits involved in fear memories.
Inferior colliculus lesions impair eyeblink conditioning in rats
Authors: Freeman John H. , Halverson Hunter E. , Hubbard Erin M.
Published: December 2007

The neural plasticity necessary for acquisition and retention of eyeblink conditioning has been localized to the cerebellum. However, the sources of sensory input to the cerebellum that are necessary for establishing learning-related plasticity have not been identified completely. The inferior colliculus may be a source of sensory input to the cerebellum through its projection to the medial auditory thalamus. The medial auditory thalamus is necessary for eyeblink conditioning in rats and projects to the lateral pontine nuclei, which then project to the cerebellar nuclei and cortex. The current experiment examined the role of the inferior colliculus in auditory eyeblink conditioning. Rats were given bilateral or unilateral (contralateral to the conditioned eye) lesions of the inferior colliculus prior to 10 d of delay eyeblink conditioning with a tone CS. Rats with bilateral or unilateral lesions showed equivalently impaired acquisition. The extent of damage to the contralateral inferior colliculus correlated with several measures of conditioning. The findings indicate that the contralateral inferior colliculus provides auditory input to the cerebellum that is necessary for eyeblink conditioning.
Internal Cooling in 4:1 AR Passages at High Rotation Numbers
Authors: Zhou Fuguo , Lagrone Jonathan , Acharya Sumanta
Published: December 2007

Heat transfer and pressure drop measurements are reported for a rotating 4:1 aspect ratio (AR) smooth two-pass coolant passage for Reynolds number in the range of 10,000–150,000, rotation number in the range of 0–0.6, and density ratios in the range of 0.1–0.2. The measurements are performed for both 90deg and 45deg orientations of the coolant passage relative to the rotational axis. A large-scale rotating heat transfer rig is utilized, with the test section consisting of segmented foil-heated elements and thermocouples. Results for the 4:1 AR indicate that beyond specific Ro values (different values for the inlet and outlet passages), the expected trends of heat transfer enhancement on the destabilized surface and degradation on the stabilized surface are arrested or reversed. Unlike the 1:1 AR, the inlet-leading surface for the 4:1 AR shows enhancement with Ro at low Re (less than 20,000) and shows the expected degradation only at high Re. Increasing the density ratio enhances the heat transfer on all walls. Orientation of the coolant passage relative to the rotational axis has an important effect, with the 45deg orientation reducing the heat transfer on the destabilized surface and enhancing it on the stabilized surface.
STUDY OF OPTICAL PROPERTIES OF POROUS SILICON PRODUCED BY METAL-AID
Authors: ZHAO YUE , LI DONGSHENG , SANG WENBIN , YANG DEREN , JIANG MINHUA
Published: December 2007

We presented fluorescence spectra and cathode-luminescence spectra of as-prepared porous silicon under different preparation conditions. The luminescence of porous silicon may be related to the luminescent centers on porous silicon surface. The luminescent efficiency depended on the porosity of porous silicon, which further depended on the oxidative level of porous silicon with metal assistance. Under back illumination, the higher the oxidative degree of the metal is, the higher is the porosity and the luminescent efficiency of porous silicon. But under front illumination, the results exhibited an opposite tendency, which can be explained by the formation theory of PS.
REVERSE AUCTION: THE LOWEST UNIQUE POSITIVE INTEGER GAME
Authors: ZENG QI , DAVIS BRUCE R. , ABBOTT DEREK
Published: December 2007

A reverse auction can be likened to a tendering process where a contract is awarded to the lowest bidder. This is in contrast to a conventional forward auction where the highest bidder wins. In this paper we analyze a minority game version of the reverse auction where an extra condition is imposed that, namely, the bid must be unique. In other words, the bidder with the lowest positive unique integer (LUPI) wins. We examine and compare two extrema, namely, the case when all players are rational and the case when all players make random selections.
BLACKBODY RADIATION: ROSETTA STONE OF HEAT BATH MODELS
Authors: O'CONNELL R. F.
Published: December 2007

The radiation field can be regarded as a collection of independent harmonic oscillators and, as such, constitutes a heat bath. Moreover, the known form of its interaction with charged particles provides a "rosetta stone" for deciding on and interpreting the correct interaction for the more general case of a quantum particle in an external potential and coupled to an arbitrary heat bath. In particular, combining QED with the machinery of stochastic physics, enables the usual scope of applications to be widened. We discuss blackbody radiation effects on: the equation of motion of a radiating electron (obtaining an equation of motion which is free from runaway solutions), anomalous diffusion, the spreading of a Gaussian wave packet, and decoherence effects due to zero-point oscillations. In addition, utilizing a formula we obtained for the free energy of an oscillator in a heat bath, enables us to determine all the quantum thermodynamic functions of interest (particularly in the areas of quantum information and nanophysics where small systems are involved) and from which we obtain temperature dependent Lamb shifts, quantum effects on the entropy at low temperature and implications for Nernst's law.
THE LENGTH OF CODING SEQUENCES IN A BACTERIAL GENOME: EVIDENCE FOR SHORT-RANGE CORRELATION
Authors: ZAINEA OANA , MORARIU VASILE V.
Published: December 2007

Series of coding sequence lengths extracted from the chromosome of Bacillus subtilis were subjected to detrended fluctuation analysis (DFA). The non-linear characteristic of the DFA plot was interpreted in terms of short-range correlation. The analysis was performed on series consisting of the whole chromosome coding sequences, as well as on the leading and lagging strands. These were compared to the same series subjected to a randomization procedure. The series were divided into two halves, which also revealed different short-range characteristics. Similar results were noticed for seven strains of Escherichia coli. Therefore, the short-range correlation characteristics are sensitive to species and strains and could be used for comparative investigations of microbial genome organization.
Serum Pepsinogen Levels,Helicobacter pyloriCagA Status, and Cytokine Gene Polymorphisms Associated with Gastric Premalignant Lesions in Costa Rica
Authors: Con Sergio A. , Con-Wong Reinaldo , Con-Chin Gil R. , Con-Chin Vicky G. , Takeuchi Hiroaki , Valerín Ana L. , Echandi Guillermo , Mena Fernando , Brenes Fernando , Yasuda Nobufumi , Araki Keijiro , Sugiura Tetsuro
Published: December 2007

The detection of gastric premalignant lesions, atrophic gastritis, corpus atrophic gastritis, and intestinal metaplasia, using several potential markers was examined in Costa Rica. Depending on the lesion investigated, from a total of 223 dyspeptic patients, 58 (26.0%), 31 (13.9%), or 23 (10.3%) were histologically diagnosed with atrophic gastritis, corpus atrophic gastritis, or intestinal metaplasia, respectively. Sera were used for the measurement of pepsinogen (PG) and Helicobacter pylori CagA antibody (CagA-ab) levels by ELISA, and human genomic DNAs were used for the genotyping of interleukin (IL)-1β (−511 and +3954), IL-10 (−1082 and −592), and IL-1RN intron 2 by PCR and RFLP. Multivariate analysis was done adjusting for sex, age, and H. pylori seropositivity. Low PG levels (L-PG; PG I ≤70 μg/L + PG I/II ≤3), very low PG levels (VL-PG; PG I ≤30 μg/L + PG I/II ≤2), and CagA-ab were individually associated with all premalignant lesions whereas IL-1β +3954T-carrier and IL-1RN homozygous 2 allele were associated with intestinal metaplasia. VL-PG, for corpus atrophic gastritis detection, was the single marker with the highest combination of test characteristics, sensitivity (77.4%), specificity (80.7%), positive predictive value (39.3%), negative predictive value (95.7%), and seropositivity rate (27.4%), expected to improve after periodic measurements. Combined examinations of VL-PG and CagA-ab improved the specificity (92.7%) and positive predictive value (62.2%), with similar sensitivity (74.2%) and negative predictive value (95.7%). In conclusion, corpus atrophic gastritis detection with periodic measurements of serum PG, alone or in combination with CagA-ab status, to identify high gastric cancer risk, seems to be the method best suited for mass screening in Costa Rica. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2631–6)
Predictors of Enrollment into a Familial Cancer Registry by Individuals at High Risk for BRCA1/2
Authors: Graves Kristi D. , Moss Lisa M. , Jasper Camille L. , DeMarco Tiffani A. , Peshkin Beth N. , Isaacs Claudine , Schwartz Marc D.
Published: December 2007

Background: Registries of individuals at risk for hereditary cancer syndromes are an invaluable resource for cancer research, yet little is known about the predictors of enrollment in hereditary cancer registries. We sought to identify the factors that characterize individuals who enroll versus those who decline participation in a Familial Cancer Registry (FCR). We also sought to identify the factors associated with provision of a blood sample to the FCR.

Methods: Participants (n = 549) had a 10% or greater prior probability of having a BRCA1/2 mutation or were members of a family with a known BRCA1/2 mutation.

Results: Of 549 participants, 81.1% (n = 445) enrolled in the FCR and 18.9% (n = 104) declined. Independent significant predictors of FCR participation included: lower anxiety (odds ratio0.5 SD, 0.83; 95% confidence interval, 0.73-0.95) and being unaffected with breast or ovarian cancer (odds ratio, 0.52; 95% confidence interval, 0.39-0.67). Of the 445 FCR participants, 80.4% provided a blood sample whereas 19.6% declined, with blood sample provision predicted by being employed full time (odds ratio, 1.68; 95% confidence interval, 1.31-2.16).

Conclusion: These findings have implications for the generalizability of results from research using hereditary cancer registry samples. Individuals who are affected with breast/ovarian cancer and have more anxiety are less likely to enroll in a hereditary cancer registry. Clinically, these results indicate that cancer registry enrollment strategies could benefit from the use of tailored approaches to increase the enrollment of individuals that are less likely to participate. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2763–7)
Inherited Predisposition of Lung Cancer: A Hierarchical Modeling Approach to DNA Repair and Cell Cycle Control Pathways
Authors: Hung Rayjean J. , Baragatti Meili , Thomas Duncan , McKay James , Szeszenia-Dabrowska Neonila , Zaridze David , Lissowska Jolanta , Rudnai Peter , Fabianova Eleonora , Mates Dana , Foretova Lenka , Janout Vladimir , Bencko Vladimir , Chabrier Amelie , Moullan Norman , Canzian Federico , Hall Janet , Boffetta Paolo , Brennan Paul
Published: December 2007

The DNA repair systems maintain the integrity of the human genome and cell cycle checkpoints are a critical component of the cellular response to DNA damage. We hypothesized that genetic variants in DNA repair and cell cycle control pathways will influence the predisposition to lung cancer, and studied 27 variants in 17 DNA repair enzymes and 10 variants in eight cell cycle control genes in 1,604 lung cancer patients and 2,053 controls. To improve the estimation of risks for specific variants, we applied a Bayesian approach in which we allowed the prior knowledge regarding the evolutionary biology and physicochemical properties of the variant to be incorporated into the hierarchical model. Based on the estimation from the hierarchical modeling, subjects who carried OGG1 326C/326C homozygotes, MGMT 143V or 178R, and CHEK2 157I had an odds ratio of lung cancer equal to 1.45 [95% confidence interval (95% CI), 1.05-2.00], 1.18 (95% CI, 1.01-1.40), and 1.58 (95% CI, 1.14-2.17). The association of CHEK2 157I seems to be overestimated in the conventional analysis. Nevertheless, this association seems to be robust in the hierarchical modeling. None of the pathways seem to have a prominent effect. In general, our study supports the notion that sequence variation may explain at least some of the variation of inherited susceptibility. In particular, further investigation of OGG1, MGMT, and CHEK2 focusing on the genetic regions where the present markers are located or the haplotype blocks tightly linked with these markers might be warranted. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2736–44)
Adduction of Human p53 Gene by Fecal Water: An In vitro Biomarker of Mutagenesis in the Human Large Bowel
Authors: Greetham Hazel L. , Bingham Sheila A. , Burns Philip A.
Published: December 2007

A polymerase arrest assay was designed to determine sites of adduction in the human p53 gene induced by incubation with fecal water. Significant formation of adducts was observed on p53 DNA after a 2-h incubation in fecal water from 10 of 17 samples studied. Large sample-to-sample variation was observed. The major sites of polymerase termination occurred at nucleotides 3′ to guanine residues. Adduct sites coincided with colorectal cancer p53 mutation “hotspots,” highlighting the potential carcinogenicity of fecal material. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2681–5)
Cytokine Genes and Pain Severity in Lung Cancer: Exploring the Influence of TNF-α-308 G/A IL6-174G/C and IL8-251T/A
Authors: Reyes-Gibby Cielito C. , Spitz Margaret , Wu Xifeng , Merriman Kelly , Etzel Carol , Bruera Eduardo , Kurzrock Razelle , Shete Sanjay
Published: December 2007

Introduction: Cytokines, aberrantly produced by cancer cells, have recently been implicated in the severity of cancer-related pain. We explored if polymorphisms in candidate cytokine genes could explain variability in self-reported pain in lung cancer patients of all stages.

Methods: Pain, clinical, and demographic variables were assessed at presentation and before any cancer treatment in 446 Whites, 125 African-Americans, and 35 Hispanics with newly diagnosed non–small cell lung cancer. We genotyped functional single nucleotide polymorphisms in tumor necrosis factor-α (TNF-α -308 G/A), interleukin-6 (IL-6) -174G/C, and IL-8 -251T/A and determined their associations with pain severity.

Results: More African-Americans (35.5%) reported severe pain (score ≥7 on a 0-10 scale) relative to Hispanics (20%) and Whites (17%; P < 0.001). We did not observe any significant association between genotypes in TNF-α, IL-6, and IL-8 and severe pain for either African-Americans or Hispanics, possibly due to small sample sizes. However, we observed that IL-8 (TT, 13%; TA + AA, 87%; P = 0.04) was significantly associated with severe pain among White patients. Logistic regression analyses showed that after controlling for epidemiologic (age and sex), clinical (stage of disease, comorbidities), and symptom (depressed mood and fatigue) variables known to influence pain severity, variant alleles in IL-8 -251T/A [odds ratio (OR), 2.35; 95% confidence interval (95% CI), 1.10-5.03; P = 0.03] persisted as a significant factor for severe pain for White patients.

Conclusions: In this preliminary analysis, we found evidence of the influence of cytokine genes on pain in White patients with lung cancer. Additional larger studies are needed to validate our findings. The long-term application is to tailored pain therapies. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2745–51)
Activated Checkpoint Kinase 2 Expression and Risk for Oral Squamous Cell Carcinoma
Authors: Yoon Angela J. , Shen Jing , Santella Regina M. , Zegarelli David J. , Chen Rongzhen , Weinstein I.B.
Published: December 2007

Background: Phosphoactivation of a DNA damage response molecule checkpoint kinase 2 (pChk2) may be a marker of oral epithelial cells that have entered the precancerous and squamous cell carcinoma (SCC) stages. We explored whether there was selective expression of pChk2 in precancerous lesions but not in nonneoplastic tissue of the oral mucosa.

Experimental Design: In a retrospective cohort design, 96 biopsied clinical leukoplakias and erythroplakias with known subsequent progression to SCC were identified from 48 subjects and assigned as the cases group. Expression status of pChk2 was compared with that of the 97 leukoplakias and erythroplakias that did not progress to SCC (control groups) by immunohistochemical analysis. Included in both groups were lesions with histologically confirmed dysplasia and those that lacked histologic evidence of atypia.

Results: Subjects with pChk2-positive but histology-negative (for atypia) lesions had an 8.6 times higher risk of developing SCC compared with those with pChk2-negative and histology-negative lesions. Overall, the presence of detectable pChk2 staining was able to identify lesions at risk of developing SCC within 3 years with a sensitivity of 85.2%, specificity of 74.2%, and predictive accuracy of 78.2% (odds ratio, 19.9; 95% confidence interval, 7.3-55.5).

Conclusion: This is the first study to include histologically nonatypical cases in the analysis of a putative biomarker for oral precancerous lesions. Our data show that pChk2 merits further investigation as a promising biomarker that can discriminate those lesions at risk for developing SCC, regardless of histologic evidence for atypia. (Cancer Epidemiol Biomarkers Prev 2007;16(12):2768–72)
Phase Precession Through Synaptic Facilitation
Authors: Thurley Kay , Leibold Christian , Gundlfinger Anja , Schmitz Dietmar , Kempter Richard
Published: December 2007

Phase precession is a relational code that is thought to be important for episodic-like memory, for instance, the learning of a sequence of places. In the hippocampus, places are encoded through bursting activity of so-called place cells. The spikes in such a burst exhibit a precession of their firing phases relative to field potential theta oscillations (4–12 Hz); the theta phase of action potentials in successive theta cycles progressively decreases toward earlier phases. The mechanisms underlying the generation of phase precession are, however, unknown. In this letter, we show through mathematical analysis and numerical simulations that synaptic facilitation in combination with membrane potential oscillations of a neuron gives rise to phase precession. This biologically plausible model reproduces experimentally observed features of phase precession, such as (1) the progressive decrease of spike phases, (2) the nonlinear and often also bimodal relation between spike phases and the animal's place, (3) the range of phase precession being smaller than one theta cycle, and (4) the dependence of phase jitter on the animal's location within the place field. The model suggests that the peculiar features of the hippocampal mossy fiber synapse, such as its large efficacy, long-lasting and strong facilitation, and its phase-locked activation, are essential for phase precession in the CA3 region of the hippocampus.