bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of 4,4′,5,5′‐Tetranitro‐2,2′‐Bi‐1H‐imidazole (TNBI)
Authors: Cho Soo Gyeong , Cho Jin Rai , Goh Eun Mee , Kim Jae‐Kyung , Damavarapu Reddy , Surapaneni Rao
Published: December 2005

We synthesized 4,4′,5,5′‐tetranitro‐2,2′‐bi‐1H‐imidazole (TNBI), which may serve as a new energetic filler for high explosive formulations. TNBI was synthesized by treating an excess amount of sodium nitrate with 2,2′‐bi‐1H‐imidazole (BI), which was produced from glyoxal and ammonia gas. The overall synthetic yield was 32%. The synthesized TNBI was characterized by performing various chemical analyses including NMR, IR, and CHN analyses. Small scale sensitivity tests were carried out at both research institutes (ADD and ARDEC). The sensitivity results varied from ‘more sensitive than RDX’ to ‘substantially less sensitive than RDX’ according to the purity and conditions of the test samples. Based on our careful characterizations, this large variation in sensitivity was attributed to the moisture content that was present in the test samples due to a hygroscopic nature of TNBI. We also found that the hygroscopic nature of TNBI changed significantly due to the amount of impurities, especially sulfates.
Enhancement of intermittent androgen ablation by “off‐cycle” maintenance with finasteride in LNCaP prostate cancer xenograft model
Authors: Eggener Scott E. , Stern Jeff A. , Jain Pankaj M. , Oram Shane , Ai Junkui , Cai Xiaoyan , Roehl Kim A. , Wang Zhou
Published: December 2005

BACKGROUND

Intermittent androgen ablation (IAA) was developed with the intention of delaying progression of prostate cancer to androgen‐independence and improving quality of life. Our previous studies suggest that relative to dihydrotestosterone (DHT), testosterone (T) is a weak inducer of proliferation and a more potent inducer of differentiation. We hypothesize that administration of finasteride (F), a type‐II 5‐α‐reductase inhibitor that increases T and decreases DHT, during the IAA “off‐cycle” would enhance the efficacy.

METHODS

After LNCaP tumor establishment, nude mice were castrated and randomized to continuous androgen ablation (CAA), continuous androgen ablation plus finasteride (CAA + F), intermittent androgen ablation (IAA), or intermittent androgen ablation plus finasteride (IAA + F).

RESULTS

After one cycle of therapy, mice treated with IAA + F had significantly less tumor growth than the other treatment groups (P = 0.002). Mice treated with IAA + F had the best survival (P = 0.048) and were 3–5 times more likely to be alive 70 days following treatment initiation.

CONCLUSIONS

IAA with finasteride provides the most favorable tumor growth kinetics and survival compared to both CAA and standard IAA. Prostate © 2005 Wiley‐Liss, Inc.
PAC1‐Rnullisoform expression in human prostate cancer tissue
Authors: Mammi Caterina , Frajese Giovanni V. , Vespasiani Giuseppe , Mariani Stefania , Gnessi Lucio , Farini Donatella , Fabbri Andrea , Frajese Gaetano , Moretti Costanzo
Published: December 2005

BACKGROUND

PACAP is a member of the VIP/GHRH family of neuropeptides and has important effects on prostate cell proliferation. Here we analyze the expression and localization of PACAP and its specific receptor variants (PAC1‐R) in tissues collected from patients undergoing prostate biopsy and surgery for benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

METHODS

Reverse transcriptase (RT)‐polymerase chain reaction (PCR), DNA sequencing, and immunohistochemistry.

RESULTS

PACAP and PAC1‐R were localized by immunohistochemistry in the prostate tissue. While in healthy and BPH tissues PAC1‐R positive staining is present in all the epithelial cells lining the lumen of the acini and in some stromal cells (mostly in the apical portion of the cells), in PCa tissues, anti‐PAC1‐R antibody stained the apical portion of the cells. We provide evidence that PAC1‐Rnulland SV1/SV2variants are all present in normal and hyperplastic tissues, while in PCa tissue PAC1‐Rnullis the most relevant receptor variant expressed.

CONCLUSIONS

Our data demonstrates that the PAC1‐Rnullvariant is the most relevant isoform expressed in human PCa tissue being suggestively related with the events determining the outcome of prostate cancer. © 2005 Wiley‐Liss, Inc.
Murine androgen‐independent neuroendocrine carcinoma promotes metastasis of human prostate cancer cell line LNCaP
Authors: Uchida Kohsuke , Masumori Naoya , Takahashi Atsushi , Itoh Naoki , Kato Kazunori , Matusik Robert J. , Tsukamoto Taiji
Published: December 2005

BACKGROUND

Although neuroendocrine (NE) cells in prostate cancer have been speculated to accelerate the growth and progression of surrounding cancer cells, the evidence is as yet inconclusive. We investigated the effect of an NE allograft (NE‐10) and its cell line, NE‐CS, which were established from the prostate of the LPB‐Tag 12T‐10 transgenic mouse, on human prostate cancer cell line LNCaP.

METHODS

The proliferation and pulmonary metastasis of LNCaP xenografts in athymic mice with and without NE‐10 allografts were evaluated. Boyden chamber assay and microarray analysis were performed to investigate changes in invasion/migration and mRNA of LNCaP cells under the influence of the NE cells, respectively.

RESULTS

NE‐10 did not influence the proliferation of LNCaP. The pulmonary metastasis of LNCaP with NE‐10 significantly increased compared to mice without it. The NE‐CS cells accelerated the in vitro invasion/migration of adenocarcinoma cells. Increased expression of mRNA of gelsolin was observed in LNCaP cells incubated with the supernatant of NE‐CS cells.

CONCLUSIONS

The NE‐10 allograft promotes pulmonary metastasis of subcutaneously inoculated LNCaP cells by facilitating cell invasion. Secretions from NE cells upregulate the expression of gelsolin, which is an actin‐binding protein, resulting in acceleration of the migration of LNCaP cells. © 2005 Wiley‐Liss, Inc.
Prostatic fluid concentrations of isoflavonoids in soy consumers are sufficient to inhibit growth of benign and malignant prostatic epithelial cells in vitro
Authors: Hedlund Tammy E. , Bokhoven Adrie van , Johannes Widya U. , Nordeen Steven K. , Ogden Lorraine G.
Published: December 2005

BACKGROUND

The differential intestinal metabolism of the soy isoflavones is likely to influence the ability of soy to prevent prostate cancer. While daidzein, genistein, and equol have direct antiproliferative effects on prostatic epithelial cells in vitro, there are no such data for the isoflavone glycitein, or seven metabolites: O‐desmethylangolensin (ODMA), 6‐hydroxyODMA (6H‐ODMA), dihydrodaidzein (DHD), cis‐4‐hydroxyequol (C4HE), 3′‐hydroxydaidzein (3HD), 6‐hydroxydaidzein (6HD), and 8‐hydroxydaidzein (8HD). In the current study, the in vitro activities of these compounds were elucidated, and the active ranges of concentrations were compared to that found in Caucasian prostatic fluid (PF) and plasma samples.

METHODS

The effects of isoflavonoids on cell growth, cell cycle distribution, and apoptosis (active Caspase 3) were examined on benign prostatic epithelial cells (PrEC), and the prostate cancer cell line LNCaP.

RESULTS

PF concentrations of genistein, equol, and daidzein (but not ODMA or DHD) were often within the ranges that reduce PrEC growth in vitro. Profound differences in sensitivities were observed with LNCaP. The hydroxydaidzeins, C4HE, and 6H‐ODMA had significant inhibitory effects at 10−5M on PrEC growth (but not LNCaP). Glycitein had significant effects on both. Reductions in cell growth were typically associated with both changes in cell cycle distribution and Caspase 3 activation. When five isoflavonoids were used in combination at concentrations present in PF samples, synergistic effects were observed.

CONCLUSION

The profound differences in sensitivities of prostatic epithelial cells to these compounds along with their synergistic effects suggest that multiple metabolites in vivo may be optimal for preventing prostate cancer. Prostate © 2005 Wiley‐Liss, Inc.
Characterization of an antibody that can detect the Kai1/CD82 murine metastasis suppressor
Authors: Custer Mary C. , Risinger John I. , Hoover Shelley , Simpson R. Mark , Patterson Tricia , Barrett J. Carl
Published: December 2005

BACKGROUND

Kai1, also known as CD82, is a member of the tetraspanin family (TM4SF). The human homolog, KAI1, is an activation antigen of T‐cells and is a metastasis suppressor for prostate and other cancers. Little is known about the mouse protein because of the lack of antibody reagents.

METHODS

Peptide immunized rabbits were used to generate polyclonal antibody to Kai1. The antibody was analyzed using immunoblotting, flow cytometry, and immunohistochemistry.

RESULTS

This antibody specifically recognizes murine Kai1 protein, crossreacts with rat Kai1 but not with human KAI1. The normal tissue distribution of this protein in mice is shown to be similar to that of the human homolog. Interestingly, mouse prostatic epithelium showed differential expression within the lobes.

CONCLUSION

This antibody, the first described that can specifically detect murine Kai1/CD82, should be very useful in addressing the mechanism of action of Kai1 in metastatic suppression. Prostate 66:567–577, 2006. © 2005 Wiley‐Liss, Inc.
A dynamic N‐capping motif in cytochrome b5: Evidence for a pH‐controlled conformational switch
Authors: Davis Ronald B. , Lecomte Juliette T.J.
Published: December 2005

Apocytochrome b5 is a marginally stable protein exhibiting under native conditions a slow conformational exchange in its C‐terminal region. The affected elements of secondary structure include a 310‐helix containing at its N‐terminus a histidine Ncap and a subsequent proline. Participation of the neutral histidine side‐chain in backbone amide capping lowers the imidazole pKa. To explore the nature of the conformational exchange in the protein and determine whether it is related to cis–trans isomerization of the His–Pro bond, three octapeptides encompassing the helix were synthesized and studied by NMR spectroscopy. One corresponded to the wild‐type sequence, the second was the D‐histidine epimer, and the third contained an alanine in place of the proline. It was found that the rates of cis–trans interconversion in the proline‐containing peptides were slower than the rates of the conformational exchange in the protein. In addition, the wild‐type peptide hinted at a predisposition for Ncap formation when in the trans configuration. Analysis of the pH response of the peptides and protein suggested that at pH near neutral, the conformational exchange detected in the protein involved only species with a trans His–Pro bond and could be approximated with a three‐state model by which the terminal helix sampled a locally unfolded state. This state, which contained an uncapped histidine with a normal pKa, partitioned into neutral and protonated populations according to pH. The intrinsic conformational bias of the wild‐type peptide and the pH‐driven equilibria illustrated how a 310‐element could serve as a nucleation site for structural rearrangement. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Accounting for loop flexibility during protein–protein docking
Authors: Bastard Karine , Prévost Chantal , Zacharias Martin
Published: December 2005

Although reliable docking can now be achieved for systems that do not undergo important induced conformational change upon association, the presence of flexible surface loops, which must adapt to the steric and electrostatic properties of a partner, generally presents a major obstacle. We report here the first docking method that allows large loop movements during a systematic exploration of the possible arrangements of the two partners in terms of position and rotation. Our strategy consists in taking into account an ensemble of possible loop conformations by a multi‐copy representation within a reduced protein model. The docking process starts from regularly distributed positions and orientations of the ligand around the whole receptor. Each starting configuration is submitted to energy minimization during which the best‐fitting loop conformation is selected based on the mean‐field theory. Trials were carried out on proteins with significant differences in the main‐chain conformation of the binding loop between isolated form and complexed form, which were docked to their partner considered in their bound form. The method is able to predict complexes very close to the crystal complex both in terms of relative position of the two partners and of the geometry of the flexible loop. We also show that introducing loop flexibility on the isolated protein form during systematic docking largely improves the predictions of relative position of the partners in comparison with rigid‐body docking. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Food plant selection by stick insects (Phasmida) in a Bornean rain forest
Authors: Blüthgen Nico , Metzner Anika , Ruf Daniel
Published: December 2005

Stick insects (Phasmida) are important herbivores in tropical ecosystems, but have been poorly investigated in their natural environment. We studied phasmids and their food plants in a tropical lowland rain forest in Borneo (Danum Valley, Sabah, Malaysia). Thirty species of phasmid were collected from 49 plant species during nocturnal surveys in the forest understorey. In most cases (35 plant species), experiments confirmed that these phasmids fed on those plant species from which they were collected. Partitioning of phasmid species among food plant species was highly significant. Two common species had a largely restricted diet: Asceles margaritatus occurred mainly on Mallotus spp. (Euphorbiaceae) and Dinophasma ruficornis on Leea indica (Leeaceae). Other phasmids fed on a broad spectrum of plant families and can be considered polyphagous (e.g. Haaniella echinata, Lonchodes hosei herberti). Feeding experiments were performed on captive phasmids using leaves from eight plant species. Asceles margaritatus showed a significantly higher consumption rate for Mallotus miquelianus leaves than for other plants, while H. echinata showed the opposite trend and the lowest consumption for M. miquelianus. However, A. margaritatus readily accepted foliage from several plant families, particularly when Mallotus was not offered at the same time. Therefore, studies on host specialisation by herbivores need to include their distribution in the natural vegetation.
Diversity and ecology of carrion- and fruit-feeding butterflies in Bornean rain forest
Authors: Hamer K. C. , Hill J. K. , Benedick S. , Mustaffa N. , Chey V. K. , Maryati M.
Published: December 2005

Tropical rain forests are well known as centres of insect diversity and much effort has focused on the role of larval host plant specificity in generating and maintaining this diversity, but fewer studies have examined the exploitation of different food resources by adults in this context. Tropical butterflies feed as adults on a wide range of resources and we examined the diversity and ecology of species feeding on rotting fruit and carrion in a tropical lowland rain forest in Sabah, Borneo. We found that species richness and diversity were significantly higher on carrion than on fruit, and that this pattern was repeated at genus and family level. There was little similarity in species assemblages on the two substrates and β-diversity between carrion and fruit comprised 33% of the total diversity of butterflies feeding on decaying matter. β-diversity between canopy gap and shade microhabitats comprised 21% of total species diversity on carrion but only 7% of the total on fruit, indicating greater functional diversity on carrion in terms of light preferences. Captures were strongly male-biased on carrion but not on fruit, and recapture rates were much lower on carrion than on fruit. Species from two subfamilies (Nymphalinae and Charaxinae) exploited both substrates and for Charaxinae, there was evidence from adult flight morphology that species on carrion were capable of faster more-powerful flight. These results support the notion of a distinctive carrion-feeding fauna comprising more mobile species, which may use carrion to meet additional nitrogen requirements resulting from greater musculature. However there was no relationship between flight morphology and substrate choice in the Nymphalinae, and carrion-feeding may not have a unitary explanation.
Effects of vegetation cover on seedling and sapling dynamics in secondary tropical wet forests in Costa Rica
Authors: Dupuy Juan Manuel , Chazdon Robin L.
Published: December 2005

We examined effects of experimental manipulations of vegetation cover on recruitment, mortality and density of seedlings (20–100 cm tall) and saplings (≥100 cm tall) of woody growth forms over a 2.5-y period. We created four treatments in each of three 15–20-y-old tropical forest stands in Costa Rica: a large canopy gap (270–350 m2), a small canopy gap (50–100 m2), understorey vegetation removal, and an unmanipulated control treatment. Creation of canopy gaps, especially large ones, increased first-year recruitment and density, as well as overall mortality of seedlings. Saplings experienced lower mortality and more prolonged gap-enhanced recruitment and density than seedlings. Removal of understorey vegetation had little or no effect on tree seedling and sapling dynamics. Recruitment and density of lianas responded only to large gaps, whereas understorey species responded to both gap treatments and to spatial heterogeneity within gaps. Tree species exhibited diverse regeneration requirements, whereas liana and understorey species were more specialized to the high and low ends of the light availability gradient, respectively. Canopy gaps provide a critical mechanism for regeneration of lianas, and canopy tree species that dominate during the early stages of secondary forest succession. The choice of management system for these secondary forests can determine the direction and rate of succession.
Do tropical species invest more in anti-herbivore defence than temperate species? A test in Eucryphia (Cunoniaceae) in eastern Australia
Authors: Hallam Amy , Read Jennifer
Published: December 2005

Tropical plants have been suggested to have higher levels of mechanical, chemical and biotic defences than temperate plants. However, comparisons have usually included deciduous species within the temperate group, which confounds the analysis since deciduous species are predicted to have a different strategy with respect to investment, nutrition and defence than evergreen species. In this study we examined levels of defence and nutrition in five evergreen species of Eucryphia occurring along a latitudinal gradient in eastern Australia, grown under common conditions in a glasshouse. From the resource-availability hypothesis we predicted the opposite gradient in defence investment, i.e. that lowest levels of defence will occur in tropical species with potentially high growth rates and annual productivity. However, we found an increase in cell wall content, total phenolics and tannin activity, and a decrease in protein availability, with decreasing latitude and/or increasing mean annual temperature. Hence, there was a trend of increasing defence (although not in leaf toughness) and declining nutritional quality towards the tropics. These latitudinal trends were recorded in both mature and expanding leaves. The same trends were observed in leaves of two species collected from the field, indicating that the results were not peculiar to the experimental growth regime. The latitudinal trend in defence did not support our prediction based on the resource availability hypothesis and may indicate that herbivore pressure is providing an overriding selection pressure, although there are alternative explanations.
Remotely sensed habitat indicators for predicting distribution of impala (Aepyceros melampus) in the Okavango Delta, Botswana
Authors: Bommel Frans P. J. van , Heitkönig Ignas M.A. , Epema Gerrit F. , Ringrose Sue , Bonyongo Casper , Veenendaal Elmar M.
Published: December 2005

We studied the spatial and temporal habitat use of impala in Botswana's Okavango Delta at landscape level with the aid of satellite imagery, with minimal fieldwork. We related remotely sensed vegetation to impala habitat preferences, by first distinguishing three vegetation types through a multi-temporal classification, and dividing these into subclasses on the basis of their Normalized Difference Vegetation Index (NDVI). This indicator for abundance and greenness of biomass was assessed for wet and dry season separately. Similarly, habitat use was assessed for both seasons by allocating vegetation classes to bimonthly impala observations. Impala distribution patterns coincided with NDVI-based subclasses of the landscape, nested within broad vegetation types, to which impala did not show a marked seasonal response. We suggest that this methodology, using limited field data, offers a functional habitat classification for sedentary herbivores, which appears particularly valuable for application in extensive areas with high spatial variability, but with restricted access.
Competitive dominance in a secondary successional rain-forest community in Borneo
Authors: Davies Stuart J. , Semui Hardy
Published: December 2005

Competitive interactions among pioneer species may have a significant impact on the course of secondary succession in tropical rain forests. We predicted that the outcome of competitive interactions in early succession would vary with soil nutrient availability. To test this hypothesis we grew seven pioneer tree species alone and in dense competitive mixtures, with four nutrient treatments: no nutrient addition, and N, P, and N plus P addition. Performance of plants grown alone and in mixtures was strongly nutrient limited. However, contrary to expectation, the competitive hierarchy among the seven species was almost identical among the four nutrient treatments. The dominant species, Melastoma malabathricum, accounted for > 70% of total stand biomass in all nutrient treatments. Seedlings of this species had higher rates of gas exchange and initial growth, and lower root allocation than the other species. Profiles of light availability within the competitive stands indicated that light levels at ground level were well above levels at which pioneer species can successfully survive and grow, yet seedlings of species other than Melastoma remained stunted. Leaf N concentrations in all stands were 25–55% reduced by competitive interactions, and N addition increased relative competitive performance in only Melastoma suggesting that Melastoma was particularly effective at N acquisition, limiting nutrient uptake by the other species. Toward the end of the experiment individuals of Melastoma began to reproduce, suggesting that the competitive hierarchy would have changed in a longer-duration experiment.
Second‐order multiple‐scattering theory associated with backscattering enhancement for a millimeter wavelength weather radar with a finite beam width
Authors: Kobayashi Satoru , Tanelli Simone , Im Eastwood
Published: December 2005

Effects of multiple scattering on reflectivity are studied for millimeter wavelength weather radars. A time‐independent vector theory, including up to second‐order scattering, is derived for a single layer of hydrometeors of a uniform density and a uniform diameter. In this theory, spherical waves with a Gaussian antenna pattern are used to calculate ladder and cross terms in the analytical scattering theory. The former terms represent the conventional multiple scattering, while the latter terms cause backscattering enhancement in both the copolarized and cross‐polarized components. As the optical thickness of the hydrometeor layer increases, the differences from the conventional plane wave theory become more significant, and essentially, the reflectivity of multiple scattering depends on the ratio of mean free path to radar footprint radius. These results must be taken into account when analyzing radar reflectivity for use in remote sensing.
Coherence between tropical East African and South American records of the Little Ice Age
Authors: Brown Erik T. , Johnson Thomas C.
Published: December 2005

Comparison of high‐resolution paleoclimate records from Lake Malawi and the Cariaco Basin reveals a consistent tropical behavior during the Little Ice Age. These records, which are interpreted to represent southward excursions of intertropical convergence zone position over southern tropical East Africa and northeastern South America, are characterized by subcentennial variability superimposed on a ramp of increasing intensity from CE 1400 to 1800. This response appears similar to that of “cold” episodes during the Late Glacial. The synchrony of these records suggests a teleconnection in tropical climate that may be a manifestation of persistent ENSO‐like conditions.
Hydrothermal fluid venting along a seismogenic detachment fault in the Moresby rift (Woodlark basin, Papua New Guinea)
Authors: Famin Vincent , Nakashima Satoru
Published: December 2005

We investigate the conditions of hydrothermal alteration occurring along an active, seismogenic normal fault dipping <30° in the Moresby rift (Woodlark basin, Papua New Guinea). Petrological and fluid inclusion studies were conducted in the samples recovered from the Ocean Drilling Program leg 180 that cored the footwall, scarp, and hanging wall of the fault. Chemical analyses of the thermodependent Si‐Al substitutions in chlorites show that synrift alteration is coeval with a temperature rise from 200°C to 300°C in the footwall of the detachment, whereas no thermal event is recorded in the hanging wall. In the same samples, fluid inclusions indicate that footwall rocks followed an isothermal exhumation path from 5–7 km to the subsurface. Taken together, the results strongly suggest that the +100°C temperature rise results from the upward migration of H2O‐NaCl fluids expelled by dehydrating metamorphic rocks from the lower crust. Fluid release began with the onset of detachment faulting and is still actively occurring nowadays. The fact that low‐angle earthquakes also occur now at 5–7 km along the fault suggests that the dehydration of the metamorphic rocks and the subsequent circulation of hot hydrothermal fluids may be responsible for the weakening of the middle crust and the formation of a detachment in the Moresby rift.
Enigmatic linear features in the Northern Hemisphere of Mars: Their formation process
Authors: Calef Fred J. , Sharpton Virgil L.
Published: December 2005

A variety of explanations have been proposed for intersecting networks of dark linear features on Mars. To better understand the origin and significance of these enigmatic linear features (ELFs), we have characterized ELFs located between 20°W and 80°W in the Northern Hemisphere of Mars. Our results show that while ELFs have several unusual characteristics, they are nevertheless dust devil tracks. Both features occur during equivalent Mars seasonal climatic conditions and trend in similar directions. While our data support the dust devil hypothesis, ELFs have atypical patterns that have implications for understanding the local and regional climate on Mars.
Gyroscopic waves in the Mediterranean Sea
Authors: van Haren Hans , Millot Claude
Published: December 2005

In the ocean outside areas of dense‐water formation, coherent vertical motions (w) are generally much weaker (∼10−3) than horizontal (u, v) ones. According to theoretical models based upon “the traditional approximation”, i.e. where the horizontal component of the Coriolis force is neglected, describing inertio‐gravity waves in the ocean interior, this holds especially for motions at the inertial frequency f: w(f) < O(10−2(u(f),v(f))). We present observations of significant w(f), with mean values of 10−1(u(f),v(f)) and occasional values of 1(u(f),v(f)), from the deep Western Mediterranean Sea characterized by very small buoyancy frequency N = 0 ± 0.4f. Our observations also present evidence of vertical propagation of internal waves, originated in the near‐surface density stratified layers, through homogeneous layers below. The observations could be interpreted only within the framework of “non‐traditional approach” with the horizontal component of the Coriolis force fully taken into account.
Flow‐topography interactions in the northern California Current System observed from geostationary satellite data
Authors: Castelao Renato M. , Barth John A. , Mavor Timothy P.
Published: December 2005

Data from Geostationary Operational Environmental Satellites are used to study the seasonal evolution of temperature fronts in the northern California Current System (CCS), focusing on the interactions with topographic features. Fronts first appear close to the coast in response to upwelling winds, moving offshore with the continuous input of energy to the system. Late in the upwelling season (after July), the upwelling front is persistently found over deeper waters south of Heceta Bank, Oregon, than north of it, suggesting that the equatorward jet separates from the shelf at Heceta Bank. Inshore of the upwelling front, weak gradients are found on the Bank. The interaction of the equatorward flow with Heceta Bank and Cape Blanco, Oregon, farther south, substantially increases the mesoscale activity and oceanic frontal habitat downstream to the south in the CCS, where fronts are persistently found greater than 100 km from the coast.
Wind‐induced seasonal angular momentum exchange at Titan's surface and its influence on Titan's length‐of‐day
Authors: Tokano Tetsuya , Neubauer Fritz M.
Published: December 2005

Titan's substantial obliquity and the global extent of the Hadley circulation give rise to seasonal variation in the mean zonal wind speed and direction in the geostrophic lower troposphere, causing an exchange of a substantial amount of angular momentum between the surface and atmosphere. The wind‐induced seasonal length‐of‐day variation calculated using the global wind profile predicted by a Titan general circulation model (GCM) amounts to 30 s in the absence of a deep subsurface ocean decoupling the outer ice shell from the ice mantle and ∼400 s in the presence of a deep subsurface ocean. This effect should give rise to longitudinal offsets of surface landmarks by ∼10 km and ∼100 km, respectively, in comparison to predicted positions based on a constant rotation rate, and may be detectable by Cassini imaging.
Seismic constraints on the present‐day kinematics of the Gargano foreland, Italy, at the transition zone between the southern and northern Apennine belts
Authors: Milano Girolamo , Di Giovambattista Rita , Ventura Guido
Published: December 2005

The 1995–2004 seismicity in the Gargano Promontory (hereafter GP) foreland at the transition zone between Southern and Northern Apennine belts (Italy) is analyzed with the aim to put constraints on the present‐day kinematics of this key‐area of the foreland. The spatial distribution of earthquakes and 54 calculated focal mechanisms show that that the main GP ruptures develop along E‐W striking, right‐lateral strike‐slip faults and NW‐SE, normal to left‐lateral second‐order faults that move in response to a prevailing NW‐SE compression (i.e. NE‐SW extension). Tacking into account the depth of the relocated seismicity and the available geological information, we propose that the GP shear zone represents an E‐W striking, major crustal discontinuity separating sectors of the foreland that move in response to the higher, northeastward propagation velocity of the thrust front of the Northern Apennines with respect to that of the Southern Apennines.
Onset conditions for equatorial spread F determined during EQUIS II
Authors: Hysell D. L. , Larsen M. F. , Swenson C. M. , Barjatya A. , Wheeler T. F. , Sarango M. F. , Woodman R. F. , Chau J. L.
Published: December 2005

An investigation into the dynamics and layer structure of the postsunset ionosphere prior to the onset of equatorial spread F (ESF) took place during the NASA EQUIS II campaign on Kwajalein Atoll on August 7 and 15, 2004. On both nights, an instrumented rocket measured plasma number density and vector electric fields to an apogee of about 450 km. Two chemical release rockets were launched both nights to measure lower thermospheric wind profiles. The Altair UHF/VHF radar was used to monitor coherent and incoherent scatter. In both experiments, strong plasma shear flow was detected. Periodic, patchy bottom‐type scattering layers were observed in the westward‐drifting plasma below the shear nodes. The large‐scale plasma depletions that formed later during ESF reproduced the periodic structure of the original, precursor layers. The layers were therefore predictive of the ESF that followed. We surmise that collisional shear instabilities may have given rise to large‐scale plasma waves that were highlighted by the bottom‐ type layer structure and that preconditioned the postsunset ionosphere for ESF.
Central Tanzanian tectonic map: A step forward to decipher Proterozoic structural events in the East African Orogen
Authors: Fritz H. , Tenczer V. , Hauzenberger C. A. , Wallbrecher E. , Hoinkes G. , Muhongo S. , Mogessie A.
Published: December 2005

On the basis of a compilation of geological maps from central Tanzania coupled with structural and petrological studies a distinction is made between the tectonic evolution of the 1.8–2.0 Ga Usagaran orogeny and the 650–580 Ma Pan‐African orogeny in the Mozambique Belt. The geometry of both orogens is determined by displacement partitioning around the indenting Tanzania Craton. The Usagaran Belt formed by strike‐slip tectonics in an island arc regime. By contrast, the Mozambique Belt formed by westward thrust propagation during oblique collision of east and west Gondwana. This resulted in a first stage of lower crustal strike slip with isobaric cooling in the eastern hinterland. Continuous forward propagation of thrusts and coeval hinterland extension accompanied an isothermal decompression phase in all units. Displacement partitioning along the oblique continental margin triggered the formation of two crustal‐scale Neoproterozoic shear belts, the dextral Central Tanzanian Shear Belt and the sinistral Kiboriani Shear Belt.
Direct evidence for nonadiabatic dynamics in atom+polyatom reactions: Crossed-jet laser studies of F+D2O→DF+OD
Authors: Ziemkiewicz Michael , Wojcik Michael , Nesbitt David J.
Published: December 2005

Quantum-state-resolved reactive-scattering dynamics of F+D2O→DF+OD have been studied at Ec.m.=5(1)kcal∕mol in low-density crossed supersonic jets, exploiting pulsed discharge sources of F atom and laser-induced fluorescence to detect the nascent OD product under single-collision conditions. The product OD is formed exclusively in the vOD=0 state with only modest rotational excitation (⟨Erot⟩=0.50(1)kcal∕mol), consistent with the relatively weak coupling of the 18.1(1)kcal∕mol reaction exothermicity into “spectator” bond degrees of freedom. The majority of OD products [68(1)%] are found in the ground (Π3∕2±2) spin-orbit state, which adiabatically correlates with reaction over the lowest and only energetically accessible barrier (ΔE≠≈4kcal∕mol). However, 32(1)% of molecules are produced in the excited spin-orbit state (Π1∕2±2), although from a purely adiabatic perspective, this requires passage over a ΔE≠≈25kcal∕mol barrier energetically inaccessible at these collision energies. This provides unambiguous evidence for nonadiabatic surface hopping in F+D2O atom abstraction reactions, indicating that reactive-scattering dynamics even in simple atom+polyatom systems is not always isolated on the ground electronic surface. Additionally, the nascent OD rotational states are well fitted by a two-temperature Boltzmann distribution, suggesting correlated branching of the reaction products into the DF(v=2,3) vibrational manifold.
Generation of single color centers by focused nitrogen implantation
Authors: Meijer J. , Burchard B. , Domhan M. , Wittmann C. , Gaebel T. , Popa I. , Jelezko F. , Wrachtrup J.
Published: December 2005

Single defect centers in diamond have been generated via nitrogen implantation. The defects have been investigated by single defect center fluorescence microscopy. Optical and electron paramagnetic resonance spectra unambiguously show that the produced defect is the nitrogen-vacancy color center. An analysis of the nitrogen flux together with a determination of the number of nitrogen-vacancy centers yields that on average one 2MeV nitrogen atom need to be implanted per defect center.
Electronic properties of interstitial iron and iron-boron pairs determined by means of advanced lifetime spectroscopy
Authors: Rein S. , Glunz S. W.
Published: December 2005

As dissolved iron is one of the most common lifetime-killing contaminants in silicon, its coexisting defect configurations, interstitial iron (Fei) and iron-boron pairs (FeB), are investigated on an intentionally iron-contaminated silicon sample by means of temperature-dependent lifetime spectroscopy (TDLS) and injection-dependent lifetime spectroscopy (IDLS). In good agreement with the literature, the study identifies the known Fei donor level at Et−EV=(0.394±0.005)eV and determines its symmetry factor as k=σn∕σp=51±5, which is an order of magnitude lower than expected from the literature. Using the well-confirmed k factor, the poorly confirmed electron-capture cross section is redetermined as σn=(3.6±0.4)×10−15cm2 at 300K. In addition, the observed exponential σ(T) dependence identifies the multiphonon emission mechanism as the dominant capture mechanism for electrons with an activation energy E∞=0.024eV. Concerning the defect related to the iron-boron pair, the study unambiguously identifies the deep FeB acceptor level as the dominant FeB recombination center. While the known average value EC−Et=(0.26±0.03)eV for the energy level is well confirmed, the symmetry factor is determined as k=0.45, which represents an intermediate value among the scattered results from the literature. Additional spectroscopic information from the defect transformation allows both capture cross sections of the FeB defect to be determined (σn=2.5×10−15cm2 and σp=5.5×10−15cm2). Being suggested as a fingerprint of iron in the literature, the crossover position of the Fei- and FeB-dominated IDLS curves (at 300K) is experimentally proved to be doping dependent which is accurately predicted on the basis of the extracted set of Fei and FeB defect parameters. An additional fingerprint of iron is found by the qualitative change of the TDLS curve upon illumination and its S-like shape under dark conditions, which represents a robust criterion for unambiguous identification of iron in silicon. As the most sensitive technique to detect and determine an iron contamination in silicon heavily relies on the Fei and FeB defect parameters, the spectroscopic results are of special practical importance.
A general purpose model for the condensed phases of water: TIP4P/2005
Authors: Abascal J. L. F. , Vega C.
Published: December 2005

A potential model intended to be a general purpose model for the condensed phases of water is presented. TIP4P/2005 is a rigid four site model which consists of three fixed point charges and one Lennard-Jones center. The parametrization has been based on a fit of the temperature of maximum density (indirectly estimated from the melting point of hexagonal ice), the stability of several ice polymorphs and other commonly used target quantities. The calculated properties include a variety of thermodynamic properties of the liquid and solid phases, the phase diagram involving condensed phases, properties at melting and vaporization, dielectric constant, pair distribution function, and self-diffusion coefficient. These properties cover a temperature range from 123to573K and pressures up to 40000bar. The model gives an impressive performance for this variety of properties and thermodynamic conditions. For example, it gives excellent predictions for the densities at 1bar with a maximum density at 278K and an averaged difference with experiment of 7×10−4g∕cm3.
Rotational spectra of the carbon-chain radicals HC5O, HC6O, and HC7O
Authors: Mohamed S. , McCarthy M. C. , Cooksy A. L. , Hinton C. , Thaddeus P.
Published: December 2005

Three new free carbon-chain radicals, HC5O, HC6O, and HC7O, and their deuterated isotopic species have been observed by Fourier transform microwave spectroscopy of a supersonic molecular beam. In contrast to the shorter HCnO radicals, these all have linear heavy-atom backbones and Π2 electronic ground states. Like the isovalent HCnS radicals, the ground states of the HCnO radicals alternate with odd and even numbers of carbon atoms: those of HC5O and HC7O are Π1∕22 and that of HC6O is Π3∕22. From frequency measurements between 6 and 26GHz, the rotational constant B, the centrifugal distortion constant D, and the lambda-type doubling and magnetic hyperfine constants have been determined to high precision for each chain. Predicted properties from coupled-cluster calculations are also reported for chains up to HC9O. The production of HCnO radicals for n even was highly favored when O2 was used as the source of oxygen, but those with n odd were best produced with CO.
Wetting in mixtures of colloids and excluded-volume polymers from density-functional theory
Authors: Bryk Paweł
Published: December 2005

We use a microscopic density-functional theory based on Wertheim's [J. Chem. Phys. 87, 7323 (1987)] first-order thermodynamic perturbation theory to study the wetting behavior of athermal mixtures of colloids and excluded-volume polymers. In opposition to the wetting behavior of the Asakura-Oosawa-Vrij [J. Chem. Phys. 22, 1255 (1954); Pure Appl. Chem. 48, 471 (1976)] model we find the polymer-rich phase to wet a hard wall. The wetting transition is of the first order and is accompanied by the prewetting transition. We do not find any hints for the layering transitions in the partial wetting regime. Our results resemble the wetting behavior in athermal polymer solutions. We point out that an accurate, monomer-resolved theory for colloid-polymer mixtures should incorporate the correct scaling behavior in the dilute polymer regime and an accurate description of the reference system.
Diffraction efficiency and diffraction bandwidth of thermal-gradient and composition-gradient crystals
Authors: Smither R. , Saleem K. Abu , Beno M. , Kurtz C. , Khounsary A. , Abrosimov N.
Published: December 2005

Measurements were made at the Advanced Photon Source at Argonne National Laboratory on the diffraction efficiency and diffraction bandwidth of a thermal-gradient crystal (Si) and a composition-gradient crystal (Si-Ge) to which a thermal gradient was applied. Gradient crystals are crystals in which the spacing between crystalline planes varies with the position in the crystal. This change in the crystal plane spacing is obtained by applying a thermal gradient to a single crystal or by growing a two-component crystal in which the ratio of the two components changes with position in the crystal. Measurements were made at two energies, 92.6 and 153 keV. Both crystals were 1-cm cubes. Laue diffraction (transmission diffraction) was used in all experiments. The thermal gradient was applied perpendicular to the [111] diffraction planes of the pure silicon crystal and perpendicular the [400] diffraction planes in the composition-gradient crystal (Si-Ge). The thermal gradient applied to the crystals was quite uniform. This resulted in nearly spherical surfaces for the crystalline planes. Changing the value of the thermal gradient applied to the crystals changed the radius of curvature of the spherical surface. The thermal gradients were varied between 0.0 and 114°C∕cm, resulting in radii of curvature from near infinity down to 40 m. By adjusting the thermal gradient applied to the crystals, one obtained diffraction efficiencies between 0.90 and 0.95 and bandwidths of up to 100 arc sec. The diffraction efficiency in the Laue geometry is defined as the ratio of the intensity of the diffracted beam to the intensity of the undiffracted beam that passes through the crystal when there is no diffraction. The length of the crystal traversed by the x-ray beam was 1.0 cm in all cases.
On BaMgAl10O17:Eu2+ phosphor degradation mechanism by vacuum-ultraviolet excitation
Authors: Bizarri G. , Moine B.
Published: December 2005

Additional to a correct color and a high efficiency, phosphors for plasma display panels must maintain their light output for thousands of hours. Often the degradation is the restricting factor in using phosphors. In this article, the mechanism of luminance decrease in blue-emitting BaMgAl10O17:Eu2+ phosphor during the operation of the PDPs has been studied. It is shown experimentally that the aging process is mainly due to the vacuum-ultraviolet excitation (VUV). It is demonstrated that the degradation mechanism can be accelerated by using a 193nm laser excitation. Based on excitation, reflectance, thermoluminescence spectra, and aging or annealing processes by laser excitation, the main causes of the degradation are demonstrated. The aging process can be separated in two different processes according to the temperature: a first one, at low temperature, corresponding to the autoionization of luminescent centers (Eu2+→Eu3+); and a second one, at high temperature, linked to the formation of traps in the phosphor. These traps induce a perturbation of the energy migration in the phosphor. In addition, the relevant parameters of trap formation are highlighted: density of the VUV excitation, temperature, and atmosphere/pressure surrounding the phosphor. A model of BaMgAl10O17:Eu2+ phosphor degradation mechanism is proposed.
Energy-transfer processes in neon-hydrogen mixtures excited by electron beams
Authors: Morozov A. , Krücken R. , Ulrich A. , Wieser J. , McCarthy T.
Published: December 2005

Energy- and charge-transfer processes in neon-hydrogen mixtures (500–1400hPa neon and 0.001–3hPa hydrogen partial pressures) excited by a pulsed low-energy (∼10keV) electron beam were investigated using time-resolved spectroscopy. Time spectra of the hydrogen Lyman-α line, neon excimer emission (second continuum), and neon atomic lines (3p–3s transitions) were recorded. The time-integrated intensity of the Lyman-α emission was measured for the same range of gas mixtures. It is shown that direct energy transfer from Ne2* excimers and neon atoms in the four lowest excited states as well as recombination of H3+ ions are the main channels populating atomic hydrogen in the n=2 state. A rate constant of (4.2±1.4)×10−11cm3s−1 was obtained for the charge transfer from Ne2+ ions to molecular hydrogen. A lower limit for the depopulation rate constant of Ne2* excimers by molecular hydrogen (combination of energy transfer and ionization) was found to be 1.0×10−10cm3s−1.
Comment on “Elimination of translational and rotational motions in nuclear orbital plus molecular orbital theory” [J. Chem. Phys. 122, 164101 (2005)]
Authors: Sutcliffe Brian
Published: December 2005

In moving-nuclei calculations on some simple diatomics and on water, Nakai et al. [J. Chem. Phys.122, 164101 (2005)] extend their earlier translation-free nuclear orbital plus molecular orbital (TF-NOMO) theory, in which the translational part of the Hamiltonian is subtracted from the full Hamiltonian, to a translation- and rotation-free approach, in which a rotational term is subtracted from the TF-NOMO Hamiltonian. It is suggested that the chosen rotational term is not unique and is not valid over all regions of space.