bluuebunny/crossref_metadata_2025 huggingface dataset:
Single photoelectron trapping, storage, and detection in a one-electron quantum dot
Authors: Rao Deepak Sethu , Szkopek Thomas , Robinson Hans Daniel , Yablonovitch Eli , Jiang Hong-Wen
Published: December 2005

There has been considerable progress in electrostatically emptying, and refilling, quantum dots with individual electrons. Typically the quantum dot is defined by electrostatic gates on a GaAs∕AlyGa1−yAs modulation-doped heterostructure. We report the filling of such a quantum dot by a single photoelectron, originating from an individual photon. The electrostatic dot can be emptied and reset in a controlled fashion before the arrival of each photon. The trapped photoelectron is detected by a point contact transistor integrated adjacent to the electrostatic potential trap. Each stored photoelectron causes a persistent negative step in the transistor channel current. Such a controllable, benign, single photoelectron detector could allow for information transfer between flying photon qubits and stored electron qubits.
New insights on the stereodynamics of ethylene adsorption on an oxygen-precovered silver surface
Authors: Gerbi Andrea , Vattuone Luca , Rocca Mario , Valbusa Ugo , Pirani Fernando , Cappelletti David , Vecchiocattivi Franco
Published: December 2005

The control of spatial orientation of molecules has a great influence on the stereodynamics of elementary processes occurring both in homogeneous and heterogeneous phases. Nonpolar molecules have so far escaped direct experimental investigations because of their poor sensitivity to several external constraints. Recently, it has been shown that the collisional alignment produced in supersonic expansions coupled with molecular-beam velocity selection can help solve such problems. Here we show that the sticking probability of ethylene, a nonpolar molecule prototypical of unsaturated hydrocarbons, on an O2-precovered Ag(001) surface is larger for molecules approaching in a helicopterlike motion than for those cartwheeling. A mechanism involving a weakly bound precursor state is suggested, with helicopter molecules having a lower chance of being scattered back into the gas phase than cartwheels when colliding with preadsorbed ethylene.
Plasma oscillations of two-dimensional electron stripe
Authors: Dmitriev Alexander , Shur Michael S.
Published: December 2005

We show that the gated two-dimensional (2D) electron gas stripe supports a high frequency plasma mode corresponding to its displacement as a whole with respect to the gate (in addition to conventional plasma waves). Similar modes should exist in multiple (parallel) 2D electron layer stripes.
Electrodynamics of microwave near-field probing: Application to medical diagnostics
Authors: Reznik Alexander N. , Yurasova Nadezhda V.
Published: December 2005

A theory for the near-field (NF) microwave diagnostics of planar-stratified media is developed based on the design of an equivalent NF probe circuit and the solution of the electrodynamical problem for the electromagnetic field of antenna in an inhomogeneous ambient medium. The theory has been verified experimentally by probing into water with controllable dielectric permittivity. A theoretical and experimental study into a possibility to locate contrast structures (malignant growths) within biological media by means of NF probing has been carried out. Detectable contrasts of a growth have been calculated depending on its dimensions and depth of occurrence. Two-dimensional images of a tumorlike contrast object have been obtained for different depths of the object submersion in water. A measurement technique reducing the masking effect of background fluctuations arising by probe contact with a pliant surface is proposed.
Enhancement of double-layer capacitance behavior and its electrical conductivity in layered poly (3, 4-ethylenedioxythiophene)-based nanocomposites
Authors: Murugan A. Vadivel , Viswanath Annamraju Kasi , Campet Guy , Gopinath Chinnakonda S. , Vijayamohanan K.
Published: December 2005

In this letter, we report on the enhanced double-layer capacitance of a layered poly (3, 4-ethylene dioxythiophene) PEDOT-MoO3 nanocomposite, which has been synthesized by a novel microwave irradiation method. The x-ray photoelectron spectroscopy analysis shows the changes in electron density and the shift in binding energy suggesting charge transfer from sulfur atoms upon PEDOT intercalation between MoO3 layers. The room-temperature conductivity for the PEDOT-MoO3 composite is found to be 1.82×10−1Scm−1, which is four orders of magnitude higher than that of the pristine oxide (3.78×10−5Scm−1). The enhanced double-layer capacitance of the PEDOT-MoO3 nanocomposite (∼300Fg−1) compared to that (∼40mFg−1) of pristine MoO3 is attributed to higher electronic conductivity, enhanced bidimensionality, and increase in surface area of the nanocomposite.
Coupled-resonator optical waveguides for biochemical sensing of nanoliter volumes of analyte in the terahertz region
Authors: Kurt Hamza , Citrin D. S.
Published: December 2005

We present a detailed study of coupled-resonator optical waveguide (CROW) based sensors for biochemical sensing. The sensitivity dependence on the CROW structure parameters, such as intercavity distance and cavity type, is investigated for the effects in the THz region of the EM spectrum of introducing small quantities of molecules, such as DNA, in the holes. Introducing the absorptive material into the low-index medium greatly affects the shape of the propagating modes of the CROW and the transmitted E-field. The shift of the resonant frequency also depends linearly on the refractive index changes for off-resonant case (dispersive effect).
Effective connecting architecture for tandem organic light-emitting devices
Authors: Chen Chieh-Wei , Lu Yin-Jui , Wu Chung-Chih , Wu Elbert Hsing-En , Chu Chih-Wei , Yang Yang
Published: December 2005

An effective connecting structure for tandem organic light-emitting devices is reported. The connecting structure consists of a thin metal layer as the common electrode, a hole-injection layer containing MoO3 on one side of the common electrode, and an electron-injection layer involving Cs2CO3 on the other side. Such a connecting structure permits efficient opposite hole and electron injection into two adjacent emitting units and gives tandem devices superior electrical and optical performances. Furthermore, the present connecting structure involves no sputtering or handling of reactive metals during device fabrication and can be prepared purely by thermal evaporation, thus rendering device processing more feasible.
Short pulse, high-repetition rate, passively Q-switched Er:yttrium-aluminum-garnet laser at 1.6 microns
Authors: Stultz Robert D. , Leyva Victor , Spariosu Kalin
Published: December 2005

We have demonstrated a continuously pumped, passively Q-switched, 1617 nm Er:yttrium-aluminum-garnet (YAG) laser oscillator with a pulse width of just under 7 ns, a pulse repetition frequency of about 4 kHz, and an output power of 0.9 W. The oscillator was pumped using an Er:fiber laser at 1534 nm, and Q switched using a Cr2+:ZnSe saturable absorber. The Er:YAG laser is useful either stand-alone, or as the master oscillator in a master-oscillator-power-amplifier architecture.
Growth of highly oriented HfO2 thin films of monoclinic phase on yttrium-stabilized ZrO2 and Si substrates by pulsed-laser deposition
Authors: Dhar S. , Ramachandra Rao M. S. , Ogale S. B. , Kundaliya Darshan C. , Shinde S. R. , Venkatesan T. , Welz S. J. , Erni R. , Browning N. D.
Published: December 2005

We report on the growth of highly oriented HfO2 thin films of monoclinic phase stabilized by 5% Co doping on (001) yttrium-stabilized zirconia (YSZ) using pulsed-laser deposition at 700°C at an oxygen partial pressure of 10−4Torr. On the other hand, pure HfO2 of such quality did not grow on YSZ in wide range of growth parameters. Rutherford backscattering-ion channeling in this film showed a 24% minimum yield (χmin) indicating highly oriented film growth, while hardly any ion channeling was observed in the undoped sample. High-resolution transmission electron microscopy revealed a sharp interface, and no signature of Co clusters. Electron energy loss spectroscopy showed that Co is in the 2+ state. Attempts were also made to grow films on a (001) Si substrate, and the results showed a very low ion channeling yield (∼8%).
Dielectric characterization of [Fe(NH2−trz)3]Br2•H2O thermal spin crossover compound by terahertz time domain spectroscopy
Authors: Mounaix P. , Lascoux N. , Degert J. , Freysz E. , Kobayashi A. , Daro N. , Létard J.-F.
Published: December 2005

The complex optical index refraction of an iron (II) spin-crossover coordination polymer is measured in the Terahertz frequency range by Terahertz time-domain spectroscopy (THz-TDS). By scanning the temperature from 288 to 333 K, we have recorded the evolution of the THz spectrum within the low spin - high spin thermal hysteresis loop. We were able to simultaneously infer the refractive index and absorption variations. The low spin-high spin transition has a marked spectral signature in the millimeter wavelength. In the 0.1–0.6 THz frequency range, the variation of real and imaginary part of the index of refraction is 6% and 20%, respectively. A marked absorption is observed above 500 GHz. The THz-TDS provides a clear direct fingerprint of this class of materials, which are interestingly potential candidates for optical data storage and processing devices.
Plasma properties downstream of a low-power Hall thruster
Authors: Beal Brian E. , Gallimore Alec D. , Hargus William A.
Published: December 2005

Triple Langmuir probes and emissive probes were used to measure the electron number density, electron temperature, and plasma potential downstream of a low-power Hall thruster. The results show a polytropic relation between electron temperature and electron number density throughout the sampled region. Over a large fraction of the plume, the plasma potential obeys the predictions of ambipolar expansion. Near the thruster centerline, however, observations show larger gradients of plasma potential than can be accounted for by this means. Radial profiles of plasma potential in the very-near-field plume are shown to contain large gradients that correspond in location to the boundaries of a visually intense plasma region.
Verification of a plasma photonic crystal for microwaves of millimeter wavelength range using two-dimensional array of columnar microplasmas
Authors: Sakai Osamu , Sakaguchi Takui , Tachibana Kunihide
Published: December 2005

We experimentally verified that a microplasma assembly can create a functional dielectric layer for the propagation of electromagnetic waves as a “plasma photonic crystal.” A two-dimensional array in a square lattice was composed of columnar plasmas of about 2mm in diameter, and the transmitted microwaves at 70–75GHz showed a change of energy flow direction. This result is attributed to the fact that periodical structure is composed of individual plasma columns with a different dispersion than the ambient part and the experimental frequency range lies in the vicinity of the lowest band gap of the photonic crystal calculated theoretically.
Soil microbial respiration responses to repeated urea applications in three grasslands
Authors: Kelliher F. M. , Sedcole J. R. , Minchin R. F. , Wan Y. , Condron L. M. , Clough T. J. , Bol R.
Published: December 2005

Grazing animals excrete urine and create transitorily high pH, nitrogen (N)-replete soil patches. Beneath grazed pasture, we postulated the soil microbial community would be highly responsive to N application. Lesser responses were expected of soils beneath grassland without grazing animals. Soil samples were collected near Lincoln, New Zealand (43.6°S, 172.5°E), beneath pasture regularly grazed by dairy cattle, an adjacent pasture set aside from grazing 20 years ago, and a nearby grassland that has never been grazed. Soil microbial respiration responses to repeated urea (500 kg N/ha) applications were determined by laboratory incubation experiments and the soil pH and water-soluble C content were also measured. The first application induced 0.13 ± 0.04 (dairy farm), 0.15 ± 0.05 (set aside), and 0.20 ± 0.04 (ungrazed) g C/kg increases in microbial respiration over 9 days, excluding carbon dioxide production from carbonate hydrolysis. After a second application, 9-day respiration increased by 0.26 ± 0.04 (dairy farm), 0.41 ± 0.04 (set aside) and 0.20 ± 0.07 (ungrazed) g C/kg. For the dairy farm and ungrazed soils, the microbial communities responded differently to repeated urea addition. The responses included transitory changes in pH and reflected the limited amounts of readily decomposable organic matter.
Microbial origin of excess methane in glacial ice and implications for life on Mars
Authors: Tung H. C. , Bramall N. E. , Price P. B.
Published: December 2005

Methane trapped in the 3,053-m-deep Greenland Ice Sheet Project 2 ice core provides an important record of millennial-scale climate change over the last 110,000 yr. However, at several depths in the lowest 90 m of the ice core, the methane concentration is up to an order of magnitude higher than at other depths. At those depths we have discovered methanogenic archaea, the
in situ
metabolism of which accounts for the excess methane. The total concentration of all types of microbes we measured with direct counts of Syto-23-stained cells tracks the excess of methanogens that we identified by their F420 autofluorescence and provides independent evidence for anomalous layers. The metabolic rate we estimated for microbes at those depths is consistent with the Arrhenius relation for rates found earlier for microbes imprisoned in rock, sediment, and ice. It is roughly the same as the rate of spontaneous macromolecular damage inferred from laboratory data, suggesting that microbes imprisoned in ice expend metabolic energy mainly to repair damage to DNA and amino acids rather than to grow. Equating the loss rate of methane recently discovered in the Martian atmosphere to the production rate by possible methanogens, we estimate that a possible Martian habitat would be at a temperature of ≈0°C and that the concentration, if uniformly distributed in a 10-m-thick layer, would be ≈1 cell per ml.
Inhibitory coupling specifically generates emergent gamma oscillations in diverse cell types
Authors: Sohal Vikaas S. , Huguenard John R.
Published: December 2005

Networks of inhibitory neurons regulate synchrony during many physiological and pathological oscillations. To explore how these effects depend on cellular, network, and synaptic factors, we developed and validated a semisynthetic inhibitory network that approximates simultaneous activity in multiple neurons by using consecutive responses from single cells. We recorded from three types of neurons, each of which forms interconnected networks
in vivo
, but has unique intrinsic properties. In all three cell types, fast inhibitory coupling generated emergent gamma oscillations. By contrast, inhibitory coupling desynchronized slower, spindle-frequency responses specifically in thalamic reticular neurons. The emergent gamma-frequency synchronization was also specific to tonic input and did not occur during responses to phasic inputs. These results illustrate how particular features of inhibitory networks (e.g., cell or input type) contribute to their synchronizing or desynchronizing functions. They also demonstrate phenomena (emergent gamma oscillations) that occur robustly in multiple cell types and may thus be a generic feature of inhibitory networks throughout the brain.
Human cancers overexpress genes that are specific to a variety of normal human tissues
Authors: Lotem Joseph , Netanely Dvir , Domany Eytan , Sachs Leo
Published: December 2005

We have analyzed gene expression data from three different kinds of samples: normal human tissues, human cancer cell lines, and leukemic cells from lymphoid and myeloid leukemia pediatric patients. We have searched for genes that are overexpressed in human cancer and also show specific patterns of tissue-dependent expression in normal tissues. Using the expression data of the normal tissues, we identified 4,346 genes with a high variability of expression and clustered these genes according to their relative expression level. Of 91 stable clusters obtained, 24 clusters included genes preferentially expressed either only in hematopoietic tissues or in hematopoietic and one to two other tissues; 28 clusters included genes preferentially expressed in various nonhematopoietic tissues such as neuronal, testis, liver, kidney, muscle, lung, pancreas, and placenta. Analysis of the expression levels of these two groups of genes in the human cancer cell lines and leukemias identified genes that were highly expressed in cancer cells but not in their normal counterparts and, thus, were overexpressed in the cancers. The different cancer cell lines and leukemias varied in the number and identity of these overexpressed genes. The results indicate that many genes that are overexpressed in human cancer cells are specific to a variety of normal tissues, including normal tissues other than those from which the cancer originated. It is suggested that this general property of cancer cells plays a major role in determining the behavior of the cancers, including their metastatic potential.
Posttranslational conversion of
l
-serines to
d
-alanines is vital for optimal production and activity of the lantibiotic lacticin 3147
Authors: Cotter Paul D. , O'Connor Paula M. , Draper Lorraine A. , Lawton Elaine M. , Deegan Lucy H. , Hill Colin , Ross R. Paul
Published: December 2005

As a general rule, ribosomally synthesized polypeptides contain amino acids only in the
l
-isoform in an order dictated by the coding DNA/RNA. Two of a total of only four examples of
l
to
d
conversions in prokaryotic systems occur in posttranslationally modified antimicrobial peptides called lantibiotics. In both examples (lactocin S and lacticin 3147), ribosomally encoded
l
-serines are enzymatically converted to
d
-alanines, giving rise to an apparent mistranslation of serine codons to alanine residues. It has been suggested that this conversion results from a two-step reaction initiated by a lantibiotic synthetase converting the gene-encoded
l
-serine to dehydroalanine (dha). By using lacticin 3147 as a model system, we report the identification of an enzyme, LtnJ, that is responsible for the conversion of dha to
d
-alanine. Deletion of this enzyme results in the residues remaining as dha intermediates, leading to a dramatic reduction in the antimicrobial activity of the producing strain. The importance of the chirality of the three
d
-alanines present in lacticin 3147 was confirmed when these residues were systematically substituted by
l
-alanines. In addition, substitution with
l
-threonine (ultimately modified to dehydrobutyrine), glycine, or
l
-valine also resulted in diminished peptide production and/or relative activity, the extent of which depended on the chirality of the newly incorporated amino acid(s).
Arterial stiffness in 10-year-old children: current and early determinants
Authors: Schack-Nielsen Lene , Mølgaard Christian , Larsen Dorthe , Martyn Christopher , Michaelsen Kim Fleischer
Published: December 2005

It has been suggested that CVD has its origins in early life. An impairment of fetal growth and early postnatal nutrition may have programming effects on cardiovascular physiology. In addition, traditional risk factors for CVD may initiate the atherosclerotic process during childhood. We explored the effect of fat intake, physical activity and lipid profile in childhood, and birth weight, growth during infancy and breast-feeding on arterial stiffness in a cohort study of ninety-three 10-year-old children followed during infancy and re-examined at the age of 10 years. Arterial stiffness in two arterial segments (aorto-radial and aorto-femoral) was measured as pulse wave velocity. Arterial stiffness was inversely associated with physical activity (a regression coefficient in cm/s (95 % CI) of −6·8 (−11·2, −2·4) and −3·9 (−6·9, −0·8) per h of high physical activity/d in the aorto-radial and aorto-femoral segments, respectively). Arterial stiffness was also positively associated with dietary fat energy percentage (3·1 (95 % CI 0·9, 5·2) and 1·8 (95 % CI 0·2, 3·2) per fat energy percentage in the aorto-radial and aorto-femoral segments, respectively) but was not related to body composition, insulin resistance or lipid profile. Arterial stiffness was also positively associated with duration of breast-feeding for the aorto-femoral segment only (2·1 (95 % CI 0·4, 3·7) per month) but was not associated with growth in early life. In conclusion, patterns of physical activity and diet, and history of breast-feeding in infancy, have an influence on the stiffness of the large arteries in children. The long-term effects of this are unknown.
A 3-month double-blind randomised study comparing an olive oil- with a soyabean oil-based intravenous lipid emulsion in home parenteral nutrition patients
Authors: Vahedi K. , Atlan P. , Joly F. , Le Brun A. , Evard D. , Perennec V. , Roux-Haguenau D. , Bereziat G. , Messing B.
Published: December 2005

Intravenous lipid emulsions (ILE) have demonstrated advantages including prevention of essential fatty acid (EFA) deficiency; however, too much EFA can down regulate fatty acid elongation leading to an imbalance of nutritional compounds in plasma and cell membranes. An olive oil-based ILE containing long-chain triacylglycerols (LCT) with a low content (20 %) of PUFA was administered for home parenteral nutrition (HPN) and compared with a conventional soyabean oil-based ILE (PUFA content, 60 %). Thirteen patients (26–92 years) with stable intestinal failure were randomised after a 1-month run-in period with a medium-chain triacylglycerols–LCT-based ILE, to receive 3 months of HPN with either olive oil- (n6) or soyabean oil-based (n7) ILE. The nutritional impact and safety of HPN, oral intakes and absorption rates, phospholipid fatty acids in plasma and lymphocyte cell membrane were assessed. The only clinical event reported was one case of pneumonia (soya group). In both groups, 20 : 3n-9:20:4n-6 ratios remained within normal ranges (0·03–0·07). There was a significant increase of γ-linolenic acid (γ-LA) in plasma and lymphocyte cell membrane (P=0·02) and of oleic acid in plasma (P<0·01) in the olive compared with the soya group. A significant correlation was found between γ-LA (day 90 – day 0) in plasma and PUFA parenteral intakes (P=0·02), but neither with fat intakes nor with fat absorption rates. In conclusion, plasma and lymphocyte EFA pattern remained in normal ranges without EFA deficiency with both lipid emulsions, despite a lower content ofn-3 andn-6 series with the olive oil-based ILE.
Postprandial glycaemic, lipaemic and haemostatic responses to ingestion of rapidly and slowly digested starches in healthy young women
Authors: Ells Louisa J. , Seal Chris J. , Kettlitz Bernd , Bal Wendy , Mathers John C.
Published: December 2005

The objective of the present study was to investigate the postprandial metabolism of two starches with contrasting rates of hydrolysis in vitro. Characterized using the Englyst method of in vitro starch classification, C*Set 06 598 contained predominantly rapidly digestible starch and C*Gel 04 201 contained predominantly slowly digestible starch. Each test starch, naturally enriched with 13C, was fed to ten healthy female volunteers as part of a moderate fat test meal (containing 75 g test starch and 21 g fat), in a double-blind randomized crossover design. The metabolic response to each starch was measured after an overnight fast, in an acute 6 h study, before and after 14 d of daily consumption of 75 g test starch. During each acute study, blood samples were taken at 15 min intervals for the first 2 h and at 30 min intervals for the remaining 4 h. Breath 13CO2 enrichment was measured at the same time points and indirect calorimetry was performed for 20 min every 40 min immediately before and throughout the study. Significantly more rapid, greater changes in postprandial plasma glucose, NEFA and serum insulin concentrations were observed after consumption of the rapidly digestible starch. Breath 13CO2 output over the first 3–4 h rose rapidly then began to decline following consumption of the rapidly digestible starch, but plateaued for the slowly digestible starch. The 14 d adaptation period did not affect any of the glycaemic or lipaemic variables but there was a reduction in postprandial plasminogen activator inhibitor-1 concentrations. These data confirm that starches characterized as predominantly rapidly digestible versus slowly digestible by the Englyst procedure provoke distinctly different patterns of metabolism postprandially.
Influence of maternal pre-pregnancy body composition and diet during early–mid pregnancy on cardiovascular function and nephron number in juvenile sheep
Authors: Gopalakrishnan G. S. , Gardner D. S. , Dandrea J. , Langley-Evans S. C. , Pearce S. , Kurlak L. O. , Walker R. M. , Seetho I. W. , Keisler D. H. , Ramsay M. M. , Stephenson T. , Symonds M. E.
Published: December 2005

The prenatal diet can program an individual's cardiovascular system towards later higher resting blood pressure and kidney dysfunction, but the extent to which these programmed responses are directly determined by the timing of maternal nutritional manipulation is unknown. In the present study we examined whether maternal nutrient restriction targeted over the period of maximal placental growth, i.e. days 28–80 of gestation, resulted in altered blood pressure or kidney development in the juvenile offspring. This was undertaken in 6-month-old sheep born to mothers fed control (100–150 % of the recommended metabolisable energy (ME) intake for that stage of gestation) or nutrient-restricted (NR; 50 % ME; n 6) diets between days 28 and 80 of gestation. Controls were additionally grouped according to normal (>3, n 7) or low body condition score (LBCS; <2, n 6), thereby enabling us to examine the effect of maternal body composition on later cardiovascular function. From day 80 to term (approximately 147 d) all sheep were fed to 100 % ME. Offspring were weaned at 12 weeks and pasture-reared until 6 months of age when cardiovascular function was determined. Both LBCS and NR sheep tended to have lower resting systolic (control, 85 (SE 2); LBCS, 77 (SE 3); NR, 77 (SE 3) mmHg) and diastolic blood pressure relative to controls. Total nephron count was markedly lower in both LBCS and NR relative to controls (LBCS, 59 (SE 6); NR, 56 (SE 12) %). Our data suggest that maternal body composition around conception is as important as the level of nutrient intake during early pregnancy in programming later cardiovascular health.
Effect of nature of dietary lipids on European sea bass morphogenesis: implication of retinoid receptors
Authors: Villeneuve Laure , Gisbert Enric , Zambonino-Infante Jose L. , Quazuguel Patrick , Cahu Chantal L.
Published: December 2005

The effect of the nature and form of supply of dietary lipids on larval development was investigated in European sea bass larvae, by considering the expression of several genes involved in morphogenesis. Fish were fed from 7 to 37 d post-hatch with five isoproteic and isolipidic compound diets incorporating different levels of EPA and DHA provided by phospholipid or neutral lipid. Phospholipid fraction containing 1·1 % (PL1 diet) to 2·3 % (PL3 diet) of EPA and DHA sustained good larval growth and survival, with low vertebral and cephalic deformities. Similar levels of EPA and DHA provided by the neutral lipid fraction were teratogenic and lethal. Nevertheless, dietary phospholipids containing high levels of DHA and EPA (PL5 diet) induced cephalic (8·5 %) and vertebral column deformities (35·3 %) adversely affecting fish growth and survival; moreover, a down-regulation ofretinoid X receptor α(RXRα),retinoic acid receptor α,retinoic acid receptor γandbone morphogenetic protein-4genes was also noted in PL5 dietary group at day 16. High levels of dietary PUFA in neutral lipid (NL3 diet) first up-regulated the expression ofRXRαat day 16 and then down-regulated most of the studied genes at day 23, leading to skeletal abnormalities and death of the larvae. A moderate level of PUFA in neutral lipids up-regulated genes only at day 16, inducing a lesser negative effect on growth, survival and malformation rate than the NL3 group. These results showed that retinoid pathways can be influenced by dietary lipids leading to skeletal malformation during sea bass larvae development.
An integrated approach to crop/livestock systems: Forage and grain production for swath grazing
Authors: Tanaka D.L. , Karn J.F. , Liebig M.A. , Kronberg S.L. , Hanson J.D.
Published: December 2005

Current agricultural systems are the result of decoupling crop/livestock enterprises for short-term economic gain at the expense of long-term sustainability. Objectives of our research were to determine the influences of winter grazing dry gestating beef cows on no-till forage and grain production, water-use efficiency, and protein and phosphorus (P) production for an oat/pea–triticale/sweet clover–corn 3-year cropping system. Oat/pea and triticale crops were harvested for grain, with the straw and chaff left in swaths after harvest for winter grazing. Drilled corn for forage was swathed in late September. Cropping system treatments were: (1) straw and corn chopped and left in place (IP); (2) straw and corn baled and removed without livestock (R); and (3) straw and corn swath grazed by livestock (L). The first winter for grazing dry, bred cows was in 1999–2000; therefore, no treatment differences occurred for the 1999 crop. In 2000, oat/pea and triticale grain and straw production for the IP treatment was about half of the production for the R treatment, because of low oat/pea and triticale plant stands on the IP treatment. Averaged over all years, corn was about 1.5 times more efficient in using water for dry matter production when compared to oat/pea or triticale. Generally, protein and P production, on a unit area basis, were highest for corn and lowest for triticale. Averaged over 4 years, about half of the nitrogen used for protein production was derived from sources other than applied commercial fertilizer. Data suggest that more than 4 years of research are needed to understand cropping system and animal interactions on forage and grain production in integrated crop/livestock systems, with trends in year four suggesting that livestock may enhance forage and grain production.
Ecotoxicological assessment of pollutant flux released from bottom ash reused in road construction
Authors: Triffault-Bouchet Gaëlle , Clément Bernard , Blake Gérard
Published: December 2005

Two approaches have been used to assess the impact of municipal solid waste incineration bottom ash on lentic ecosystems, especially lake coastlines. One of the aims of this study was to complete the methodology for the assessment of waste ecocompatibility by assessing a scenario in which bottom ashes are reused as road embankment. A laboratory lysimeter was chosen to simulate the road embankment and produce the bottom ash leachate. The first approach was based on three bioassays. Results led to the following ranking of these bioassays based on organisms sensitivity, in descending order: algae Pseudokirchneriella subcapitata > duckweed Lemna minor > cladoceran Daphnia magna. At the same time, leachates were assessed with a 2 litre freshwater/sediment microcosm. All species were impaired. Toxicity effects increased with leachate concentration, from 1.56% to 8.0%. Comparison between bioassays and microcosm assays revealed that the representativeness is higher in the multispecies systems. Finally, bottom ashes have been assessed in a simplified risk assessment procedure. Predicted environmental concentration is close to the concentration that caused first effects in microcosms. Recommendations are made for the reuse of bottom ashes as road embankment.
Biodiversity and aquatic ecosystem functioning: A mini-review
Authors: Humbert J.-F. , Dorigo U.
Published: December 2005

Ecosystem functioning depends on multiple interactions among physical, chemical and biological factors. Indeed, ecosystem processes (e.g., productivity and nutrient recycling) result directly from the diversity of functional traits in biotic communities, which in turn are determined by species composition and diversity. Species diversity results both from biotic introductions and from environmental pressures. As a result, changes in biodiversity in response to environmental selection pressures tend to have a direct impact on ecosystem processes. The relationships between biodiversity and ecosystem functioning have been the focus of numerous research studies for several years. Based on these studies, it appears that a low level of biodiversity allows an ecosystem to function effectively under constant conditions, but that greater biodiversity is called for in fluctuating environments. In this paper, we outline the concepts underlying the relationships between biodiversity and ecosystem functioning, and illustrate these concepts with examples from aquatic ecosystems. The importance of spatial scale will also be considered.
Handball and Aggression: An investigation of adolescent handball players’ perceptions of aggressive behavior
Authors: Stornes Tor , Roland Erling
Published: December 2005

This study investigated different forms of aggression in a cross‐sectional study of 14‐ to 16‐year‐old male handball players in Norway. Players responded to an inventory measuring an aggressive winning strategy (Instrumental Aggres‐sion) containing items like: “I often play aggressively to win the game” as well as personal dispositions to act with anger caused by a frustrating or aversive event (Reactive Aggression) and personal dispositions to behave aggressively to gain power or increase the affiliation with others (Proactive Aggression). The aggressive winning strategy (Instrumental Aggression) correlated posi‐tively and significantly with one of the dimensions of Reactive Aggression (Temperament‐Related Reactive Aggression) and one of the dimensions of Proactive Aggression (Power‐Related Proactive Aggression). Results may sug‐gest that by stimulating an aggressive winning strategy, the handball arena may become an arena for violence and hostile attitudes incompatible with ideals of sportspersonship.
Hsp27 Enhances Recovery of Splicing as well as Rephosphorylation of SRp38 after Heat Shock
Authors: Marin-Vinader Laura , Shin Chanseok , Onnekink Carla , Manley James L. , Lubsen Nicolette H.
Published: December 2005

A heat stress causes a rapid inhibition of splicing. Exogenous expression of Hsp27 did not prevent that inhibition but enhanced the recovery of splicing afterward. Another small heat shock protein, αB-crystallin, had no effect. Hsp27, but not αB-crystallin, also hastened rephosphorylation of SRp38—dephosphorylated a potent inhibitor of splicing—after a heat shock, although it did not prevent dephosphorylation by a heat shock. The effect of Hsp27 on rephosphorylation of SRp38 required phosphorylatable Hsp27. A Hsp90 client protein was required for the effect of Hsp27 on recovery of spicing and on rephosphorylation of SRp38. Raising the Hsp70 level by either a pre-heat shock or by exogenous expression had no effect on either dephosphorylation of SRp38 during heat shock or rephosphorylation after heat shock. The phosphatase inhibitor calyculin A prevented dephosphorylation of SRp38 during a heat shock and caused complete rephosphorylation of SRp38 after a heat shock, indicating that cells recovering from a heat shock are not deficient in kinase activity. Together our data show that the activity of Hsp27 in restoring splicing is not due to a general thermoprotective effect of Hsp27, but that Hsp27 is an active participant in the (de)phosphorylation cascade controlling the activity of the splicing regulator SRp38.
MAGI-1 Is Required for Rap1 Activation upon Cell-Cell Contact and for Enhancement of Vascular Endothelial Cadherin-mediated Cell Adhesion
Authors: Sakurai Atsuko , Fukuhara Shigetomo , Yamagishi Akiko , Sako Keisuke , Kamioka Yuji , Masuda Michitaka , Nakaoka Yoshikazu , Mochizuki Naoki
Published: December 2005

Rap1 is a small GTPase that regulates adherens junction maturation. It remains elusive how Rap1 is activated upon cell-cell contact. We demonstrate for the first time that Rap1 is activated upon homophilic engagement of vascular endothelial cadherin (VE-cadherin) at the cell-cell contacts in living cells and that MAGI-1 is required for VE-cadherin-dependent Rap1 activation. We found that MAGI-1 localized to cell-cell contacts presumably by associating with β-catenin and that MAGI-1 bound to a guanine nucleotide exchange factor for Rap1, PDZ-GEF1. Depletion of MAGI-1 suppressed the cell-cell contact-induced Rap1 activation and the VE-cadherin-mediated cell-cell adhesion after Ca2+switch. In addition, relocation of vinculin from cell-extracellular matrix contacts to cell-cell contacts after the Ca2+switch was inhibited in MAGI-1-depleted cells. Furthermore, inactivation of Rap1 by overexpression of Rap1GAPII impaired the VE-cadherin-dependent cell adhesion. Collectively, MAGI-1 is important for VE-cadherin-dependent Rap1 activation upon cell-cell contact. In addition, once activated, Rap1 upon cell-cell contacts positively regulate the adherens junction formation by relocating vinculin that supports VE-cadherin-based cell adhesion.
Brd4 Is Required for Recovery from Antimicrotubule Drug-induced Mitotic Arrest: Preservation of Acetylated Chromatin
Authors: Nishiyama Akira , Dey Anup , Miyazaki Jun-ichi , Ozato Keiko
Published: December 2005

The mammalian bromodomain protein Brd4 interacts with mitotic chromosomes by binding to acetylated histone H3 and H4 and is thought to play a role in epigenetic memory. Mitotic cells are susceptible to antimicrotubule drugs. These drugs activate multiple response pathways and arrest cells at mitosis. We found that Brd4 was rapidly released from chromosomes upon treatment with antimicrotubule drugs, including the reversible agent nocodazole. Yet, when nocodazole was withdrawn, Brd4 was reloaded onto chromosomes, and cells proceeded to complete cell division. However, cells in which a Brd4 allele was disrupted (Brd4+/-), and expressing only half of the normal Brd4 levels, were defective in reloading Brd4 onto chromosomes. Consequently, Brd4+/- cells were impaired in their ability to recover from nocodazole-induced mitotic arrest: a large fraction of +/- cells failed to reach anaphase after drug withdrawal, and those that entered anaphase showed an increased frequency of abnormal chromosomal segregation. The reloading defect observed in Brd4+/- cells coincided with selective hypoacetylation of lysine residues on H3 and H4. The histone deacetylase inhibitor trichostatin A increased global histone acetylation and perturbed nocodazole-induced Brd4 unloading. Brd4 plays an integral part in a cellular response to drug-induced mitotic stress by preserving a properly acetylated chromatin status.
Rootletin Interacts with C-Nap1 and May Function as a Physical Linker between the Pair of Centrioles/Basal Bodies in Cells
Authors: Yang Jun , Adamian Michael , Li Tiansen
Published: December 2005

Rootletin, a major structural component of the ciliary rootlet, is located at the basal bodies and centrosomes in ciliated and nonciliated cells, respectively. Here we investigated its potential role in the linkage of basal bodies/centrioles and the mechanism involved in such linkages. We show that rootletin interacts with C-Nap1, a protein restricted at the ends of centrioles and functioning in centrosome cohesion in interphase cells. Their interaction in vivo is supported by their colocalization at the basal bodies/centrioles and coordinated association with the centrioles during the cell cycle. Ultrastructural examinations demonstrate that rootletin fibers connect the basal bodies in ciliated cells and are present both at the ends of and in between the pair of centrioles in nonciliated cells. The latter finding stands in contrast with C-Nap1, which is present only at the ends of the centrioles. Transient expression of C-Nap1 fragments dissociated rootletin fibers from the centrioles, resulting in centrosome separation in interphase. Overexpression of rootletin in cells caused multinucleation, micronucleation, and irregularity of nuclear shape and size, indicative of defects in chromosome separation. These data suggest that rootletin may function as a physical linker between the pair of basal bodies/centrioles by binding to C-Nap1.
Multiple Alignment of protein structures and sequences for VMD
Authors: Eargle John , Wright Dan , Luthey-Schulten Zaida
Published: December 2005

Multiple Alignment is a new interface for performing and analyzing multiple protein structure alignments. It enables viewing levels of sequence and structure similarity on the aligned structures and performing a variety of evolutionary and bioinformatic tasks, including the construction of structure-based phylogenetic trees and minimal basis sets of structures that best represent the topology of the phylogenetic tree. It is implemented as a plugin for VMD (Visual Molecular Dynamics), which is distributed by the NIH Resource for Macromolecular Modeling and Bioinformatics at the University of Illinois.

Availability: Both binary and source code downloads for VMD 1.83, which includes Multiple Alignment, are available from . The Multidimensional QR factorization algorithm is available at

Contact:  multiseq@scs.uiuc.edu
Nanoprinting onto cells
Authors: Curtis Adam S.G , Dalby Matthew J , Gadegaard Nikolaj
Published: December 2005

Growing cells on surfaces bearing nanotopography signals makes many changes in cell gene expression and downstream changes in phenotype but the mechanisms for this have, so far, been obscure. We consider the question of whether the topography directly nanoimprints onto the cell as a component of the signal transduction system. Evidence we present from SEM, TEM and fluorescence detection of the arrangements of cytoskeletal components is consistent with the possibility that cells are nanoimprinted by the substrate. The nanoprinting does not interfere with integrin-mediated adhesion processes and may perhaps work through them. Time-lapse video studies of cells moving from areas bearing nanotopography to flat areas and vice versa suggests that the nanoimprinting takes 1–6 h to appear on the cell and a similar time to disappear when the cell moves from a flat surface to a nanotopographic one and back. This nanoprinting of cells would appear to be a novel type of cell signalling.
Jeans instability in a self-gravitating dusty plasma
Authors: Shukla P.K , Stenflo L
Published: December 2005

We present a multi-fluid theory for the Jeans instability accounting for an attractive force between two equally charged dust particles in a self-gravitating plasma. Our analyses which includes the electrostatic energy between two charged dust grains provides a possibility of resolving the ‘Jeans swindle’, in addition to obtaining a Jeans instability with a faster growth rate. The relevance of our investigation to the formation of planetesimals and collapse of interstellar clouds in star forming regions is discussed.
The properties of foams and lattices
Authors: Ashby M.F
Published: December 2005

Man and nature both exploit the remarkable properties of cellular solids, by which we mean foams, meshes and microlattices. To the non-scientist, their image is that of soft, compliant, things: cushions, packaging and padding. To the food scientist they are familiar as bread, cake and desserts of the best kind: meringue, mousse and sponge. To those who study nature they are the structural materials of their subject: wood, coral, cancellous bone. And to the engineer they are of vast importance in building lightweight structures, for energy management, for thermal insulation, filtration and much more.

When a solid is converted into a material with a foam-like structure, the single-valued properties of the solid are extended. By properties we mean stiffness, strength, thermal conductivity and diffusivity, electrical resistivity and so forth. And the extension is vast—the properties can be changed by a factor of 1000 or more. Perhaps the most important concept in analysing the mechanical behaviour is that of the distinction between astretch- and abending-dominated structure. The first is exceptionally stiff and strong for a given mass; the second is compliant and, although not strong, it absorbs energy well when compressed. This paper summarizes a little of the way in which the mechanical properties of cellular solids are analysed and illustrates the range of properties offered by alternative configurations.
High surface area silicon materials: fundamentals and new technology
Authors: Buriak Jillian M
Published: December 2005

Crystalline silicon forms the basis of just about all computing technologies on the planet, in the form of microelectronics. An enormous amount of research infrastructure and knowledge has been developed over the past half-century to construct complex functional microelectronic structures in silicon. As a result, it is highly probable that silicon will remain central to computing and related technologies as a platform for integration of, for instance, molecular electronics, sensing elements and micro- and nanoelectromechanical systems.

Porous nanocrystalline silicon is a fascinating variant of the same single crystal silicon wafers used to make computer chips. Its synthesis, a straightforward electrochemical, chemical or photochemical etch, is compatible with existing silicon-based fabrication techniques. Porous silicon literally adds an entirely new dimension to the realm of silicon-based technologies as it has a complex, three-dimensional architecture made up of silicon nanoparticles, nanowires, and channel structures. The intrinsic material is photoluminescent at room temperature in the visible region due to quantum confinement effects, and thus provides an optical element to electronic applications.

Our group has been developing new organic surface reactions on porous and nanocrystalline silicon to tailor it for a myriad of applications, including molecular electronics and sensing. Integration of organic and biological molecules with porous silicon is critical to harness the properties of this material. The construction and use of complex, hierarchical molecular synthetic strategies on porous silicon will be described.
Porous materials for thermal management under extreme conditions
Authors: Clyne T.W , Golosnoy I.O , Tan J.C , Markaki A.E
Published: December 2005

A brief analysis is presented of how heat transfer takes place in porous materials of various types. The emphasis is on materials able to withstand extremes of temperature, gas pressure, irradiation, etc., i.e. metals and ceramics, rather than polymers. A primary aim is commonly to maximize either the thermal resistance (i.e. provide insulation) or the rate of thermal equilibration between the material and a fluid passing through it (i.e. to facilitate heat exchange). The main structural characteristics concern porosity (void content), anisotropy, pore connectivity and scale. The effect of scale is complex, since the permeability decreases as the structure is refined, but the interfacial area for fluid–solid heat exchange is, thereby, raised. The durability of the pore structure may also be an issue, with a possible disadvantage of finer scale structures being poor microstructural stability under service conditions. Finally, good mechanical properties may be required, since the development of thermal gradients, high fluid fluxes, etc. can generate substantial levels of stress. There are, thus, some complex interplays between service conditions, pore architecture/scale, fluid permeation characteristics, convective heat flow, thermal conduction and radiative heat transfer. Such interplays are illustrated with reference to three examples: (i) a thermal barrier coating in a gas turbine engine; (ii) a Space Shuttle tile; and (iii) a Stirling engine heat exchanger. Highly porous, permeable materials are often made by bonding fibres together into a network structure and much of the analysis presented here is oriented towards such materials.