bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid nanofabrication processes utilizing diblock copolymer nanotemplate prepared by self-assembled monolayer based surface neutralization
Authors: Kim Su-Jin , Maeng W. J. , Lee S. K. , Park D. H. , Bang Sung Hwan , Kim Hyungjun , Sohn Byeong-Hyeok
Published: February 2008

Nanostructures including nanohole and metal dot arrays were fabricated by hybrid processes combing self-assembled diblock copolymer and conventional semiconductor processes. The interfacial energy between polystyrene-b-polymethylmetacrylate (PS-b-PMMA) diblock copolymer and substrate surface was controlled by employing a self-assembled monolayer (SAM), resulting in a polymer template with well-ordered cylindrical nanohole array. The nanohole sizes were controlled within 10 to 22 nm in diameter using block copolymers with different molecular weights. The PS nanotemplates were fabricated on various substrates, including oxides, nitrides, and poly-Si. Nanohole pattern was transferred by dry etching process, producing inorganic nanohole templates. Also, gold nanodot arrays with diameter smaller than 10 nm were fabricated through lift off process.
Erbium silicide formation and its contact properties on Si(100)
Authors: Huang W. , Ru G. P. , Jiang Y. L. , Qu X. P. , Li B. Z. , Liu R. , Lu F.
Published: February 2008

Erbium silicide formation and its contact properties on Si(100) have been studied in this work. With sputtering and rapid thermal annealing, the deposited Er was found to react with the Si(100) substrate upon 300 °C annealing. The formed ErSi2−x is stable up to 1000 °C annealing. Problems of surface oxidation and defect formation were discussed. Pinhole or pyramidal defect was observed to form in the ErSi2−x films depending on the initial Er thickness. The electrical characteristics of ErSi2−x/p-Si(100) Schottky contacts were measured at room temperature for the annealing temperature ranging from 500 to 900 °C and Schottky barrier height (SBH) was found to vary between 0.783 and 0.805 eV. ErSi2−x/n-Si(100) contacts formed after annealing at a temperature from 500 to 900 °C, which have much lower SBHs, were characterized by temperature-dependent current-voltage measurement. The measurement results were analyzed with a Gaussian distribution model of the inhomogeneous SBH. The mean SBHs were extracted to be 0.343−0.427 eV for different annealing temperatures. The standard deviation of the SBH was found to be larger for the ErSi2−x/n-Si(100) diodes annealed at 700, 800, and 900 °C than for those annealed at 500 and 600 °C.
Luminescence uniformity studies on dendrite bamboo carbon submicron-tube field-emitter arrays
Authors: Li Xin , Ding Fuqiang , Liu Weihua , He Yongning , Zhu Changchun
Published: February 2008

This is a study on the field emission (FE) from carbon submicron-tube multiwall covered with carbon nanotubes (MWCNTs), which forms a dendrite structure as a field-emitter array, by chemical vapor deposition method. To improve the FE luminescence uniformity, the bamboo carbon submicron tubes are grown on a reactive current limiting layer. We show that the same screening effect observed on MWCNT field emitters has been eliminated because the emitter tip distance of bamboo carbon submicron tubes is large enough, such as larger than twofold the diameter. A low turn-on field of ∼1.1V∕μm and a high current density of ∼500μA∕cm2 were obtained. The FE aging property curve shows current stability has been improved, and the luminescence uniformity has been improved as can be seen from the luminescence photo with four layers.
Reducing imaging defects in high-resolution photolithography
Authors: Wang Fei , Stanton William A.
Published: February 2008

Photoresist defects can occur in large, seemingly noncritical features in high-resolution photolithography although it is capable of resolving features of much smaller dimensions. Both optical illumination and wafer topography may contribute to the formation of resist defects in large features. This letter examines optical simulations to uncover the specific nature of these resist defects and proposes local correction methods to improve the photolithographic process. For example, adding a back-etched phase feature in the center of a large isolated trench feature reduces the illumination-responsible resist scumming effect, and optimizing the multilayered film stack can eliminate the resist defect when printing a large contact feature on the structured wafer substrate.
Realization of ultrashallow junctions by plasma immersion ion implantation and laser annealing
Authors: Vervisch V. , Etienne H. , Torregrosa F. , Roux L. , Ottaviani L. , Pasquinelli M. , Sarnet T. , Delaporte P.
Published: February 2008

To achieve the requirements of the 45nm ITRS technology node and beyond, beamline implantation has reached its limit in terms of low energies. Plasma immersion ion implantation (PIII) is thus an alternative doping technique for the formation of ultrashallow junctions for source/drain extension in silicon devices. In this study, the authors present some results obtained on the PIII prototype called PULSION® designed by the IBS French company. In previous works [F. Torregrosa et al., Proceedings of the 14th International Conference on Ion Implant Technology, 2004 (unpublished); Proceedings of the 16th International Conference on Ion Implant Technology, 2006 (unpublished), p. 6], it has been shown that this machine offers the possibility to reach ultralow energy implantations and then to obtain implantation depths of only a few nanometers. One of the main issues is then to highly activate these junctions with a limited diffusion of dopants. Wafers have been implanted by PULSION® with acceleration voltages from 1to2kV at saturation dose, with or without preamorphization implantation (PAI). Then, they have been annealed by a XeCl excimer laser with a wavelength of 193nm, with energy densities from 275to600mJ∕cm2 and several shots. Electrical and physicochemical characterizations such as secondary-ion-mass spectrometry, four-point probe, and optical noncontact measurements were then performed. In this article, the authors investigate the effects of PAI, implantation parameters, and laser fluence on the junction specifications (depth, sheet resistance, and leakage current).
Proximity effects in nanoscale patterning with high resolution electron beam induced deposition
Authors: Crozier Peter A.
Published: February 2008

Electron beam induced deposition can be used to deposit dots as small as 1nm on planar substrates. However, more complex patterns composed of arrays of closely space dots may be distorted because of proximity effects arising from the fundamental nature of secondary electron generation. These proximity effects are investigated by exploring the visibility of nanoscale letters fabricated by dissociating a Pt organometallic precursor onto a Si3N4 substrate. The pattern visibility and deposited mass distribution have been investigated for letters with widths of 5–20nm. Letter visibility is very good down to 10nm but the pattern is completely obscured by 5nm. Moreover, the deposited mass distribution for 5nm width letters bears almost no resemblance to the pattern traced by the primary electron beam. The mass distribution for the component dots employed here has a Lorentzian distribution with a full width at half maximum of 2.3nm. The overlap in the tails of the Lorentzian contributes to a reduction in the visibility of the 10nm sized letters. However, for patterns formed with dots separated by less than 2nm, additional electrons are emitted from previously deposited nearby regions, substantially destroying the pattern for letters of width equal to 5nm.
Mechanistic study of plasma damage of low k dielectric surfaces
Authors: Bao J. , Shi H. , Liu J. , Huang H. , Ho P. S. , Goodner M. D. , Moinpour M. , Kloster G. M.
Published: February 2008

Plasma damage to low k dielectric materials was investigated from a mechanistic point of view. Low k dielectric films were treated by Ar, O2, N2, N2∕H2, and H2 plasmas in a standard reactive ion etching chamber and the damage was characterized by angle resolved x-ray photoelectron spectroscopy, x-ray reflectivity, Fourier transform infrared spectroscopy, and contact angle measurements. Both carbon depletion and surface densification were observed on the top surface of damaged low k materials while the bulk remained largely unaffected. Plasma damage was found to be a complicated phenomenon involving both chemical and physical effects, depending on chemical reactivity and the energy and mass of the plasma species. A downstream hybrid plasma source with separate ions and atomic radicals was employed to study their respective roles in the plasma damage process. Ions were found to play a more important role in the plasma damage process. The dielectric constant of low k materials can increase up to 20% due to plasma damage and we attributed this to the removal of the methyl group making the low k surface hydrophilic. Annealing was generally effective in mitigating moisture uptake to restore the k value but the recovery was less complete for higher energy plasmas. Quantum chemistry calculation confirmed that physisorbed water in low k materials induces the largest increase of dipole moments in comparison with changes of surface bonding configurations, and is primarily responsible for the dielectric constant increase.
Low-temperature c-axis oriented growth of nanocrystalline ZnO thin films on Si substrates by plasma assisted pulsed laser deposition
Authors: Shao J. , Shen Y. Q. , Sun J. , Xu N. , Yu D. , Lu Y. F. , Wu J. D.
Published: February 2008

Nanocrystalline zinc oxide (nc-ZnO) thin films with c-axis orientation were deposited on Si (100) substrates at a temperature lower than 100 °C by plasma assisted pulsed laser deposition from metallic zinc. Oxygen plasma generated by electron cyclotron resonance (ECR) microwave discharge was used as a reactive and energetic source to assist reactive deposition and oriented growth of nc-ZnO thin films. Atomic force microscopy (AFM) observation revealed the smooth surface appearance of the deposited nc-ZnO films. Analysis from Raman scattering and Fourier-transform infrared spectroscopy (FTIR) demonstrated the wurtzite structure of the deposited films. Structural characterization from x-ray diffraction (XRD) analysis showed the film growth with c-axis orientation perpendicular to the substrate surface and the nanocrystalline formation with average c-axis-oriented crystallites of 12 nm. The deposited nc-ZnO films are optically transparent in the visible and near infrared regions and the optical band gap was determined to be 3.32 eV.
Effect of bis-(3-sodiumsulfopropyl disulfide) byproducts on copper defects after chemical mechanical polishing
Authors: Hung Chi-Cheng , Lee Wen-Hsi , Hu Shao-Yu , Chang Shih-Chieh , Chen Kei-Wei , Wang Ying-Lang
Published: February 2008

In the semiconductor metallization process, the superior gap-fill capability of copper (Cu) electroplating is mainly due to external additives, such as bis-(3-sodiumsulfopropyl disulfide) (SPS), which is used as an accelerator. This study demonstrates that the byproducts of SPS induced Cu defects after a chemical-mechanical-polishing (CMP) process. In conventional cyclic-voltammetric-stripping analysis, the byproducts generated from organic additives are very difficult to quantify. In this study, the authors used mass-spectrum analysis to quantify SPS byproducts and found that the SPS byproduct, 1,3-propanedisulfonic acid, correlated with the formation of Cu defects because it influenced the properties of electroplated Cu films and the chemical corrosion rate, then induced defects after the CMP process.
Characterization of an ultrashallow junction structure using angle resolved x-ray photoelectron spectroscopy and medium energy ion scattering
Authors: Saheli G. , Conti G. , Uritsky Y. , Foad M. A. , Brundle C. R. , Mack P. , Kouzminov D. , Werner M. , van den Berg J. A.
Published: February 2008

The control of dose and energy (and therefore depth distribution) of ion implantation in n-channel MOSFET (NMOS) ultrashallow junctions is vital. Therefore there is a need to provide reliable metrology. Since the standard sheet resistance probing method, and the dynamic secondary ion mass spectroscopy method used to calibrate it both become more problematic for very shallow junctions, other techniques need to be evaluated. Angle resolved x-ray photoelectron spectroscopy (AR-XPS) is investigated here as an additional, nondestructive, laboratory-based tool to characterize NMOS junctions. The arsenic depth distribution and chemical bonding configuration are investigated for a set of p-type wafers implanted at 2keV with nominal doses from 1×1015to2×1015at.∕cm2. The results are compared to those using medium energy ion scattering (MEIS). It is demonstrated that XPS is a useful nondestructive tool for obtaining dopant chemical bonding state, qualitative elemental and chemical state depth information without modeling, and quantitative information on overlayer film thickness. Modeling the AR-XPS data and comparison to trial depth structures can lead to a more quantitative, but crude, depth profile. The combination of AR-XPS and MEIS was also able to explain why secondary ion mass spectroscopy profiling measures an approximately 2% increase for 1×1015at.∕cm2 in apparent dose on annealing the arsenic as-implanted wafer.
Sr Lattice Clock at 1 × 10
–16
Fractional Uncertainty by Remote Optical Evaluation with a Ca Clock
Authors: Ludlow A. D. , Zelevinsky T. , Campbell G. K. , Blatt S. , Boyd M. M. , de Miranda M. H. G. , Martin M. J. , Thomsen J. W. , Foreman S. M. , Ye Jun , Fortier T. M. , Stalnaker J. E. , Diddams S. A. , Le Coq Y. , Barber Z. W. , Poli N. , Lemke N. D. , Beck K. M. , Oates C. W.
Published: February 2008

Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between them. We have realized a high-performance remote comparison of optical clocks over kilometer-scale urban distances, a key step for development, dissemination, and application of these optical standards. Through this remote comparison and a proper design of lattice-confined neutral atoms for clock operation, we evaluate the uncertainty of a strontium (Sr) optical lattice clock at the 1 × 10
–16
fractional level, surpassing the current best evaluations of cesium (Cs) primary standards. We also report on the observation of density-dependent effects in the spin-polarized fermionic sample and discuss the current limiting effect of blackbody radiation–induced frequency shifts.
Neurokinin 1 Receptor Antagonism as a Possible Therapy for Alcoholism
Authors: George David T. , Gilman Jodi , Hersh Jacqueline , Thorsell Annika , Herion David , Geyer Christopher , Peng Xiaomei , Kielbasa William , Rawlings Robert , Brandt John E. , Gehlert Donald R. , Tauscher Johannes T. , Hunt Stephen P. , Hommer Daniel , Heilig Markus
Published: February 2008

Alcohol dependence is a major public health challenge in need of new treatments. As alcoholism evolves, stress systems in the brain play an increasing role in motivating continued alcohol use and relapse. We investigated the role of the neurokinin 1 receptor (NK1R), a mediator of behavioral stress responses, in alcohol dependence and treatment. In preclinical studies, mice genetically deficient in NK1R showed a marked decrease in voluntary alcohol consumption and had an increased sensitivity to the sedative effects of alcohol. In a randomized controlled experimental study, we treated recently detoxified alcoholic inpatients with an NK1R antagonist (LY686017;
n
= 25) or placebo (
n
= 25). LY686017 suppressed spontaneous alcohol cravings, improved overall well-being, blunted cravings induced by a challenge procedure, and attenuated concomitant cortisol responses. Brain functional magnetic resonance imaging responses to affective stimuli likewise suggested beneficial LY686017 effects. Thus, as assessed by these surrogate markers of efficacy, NK1R antagonism warrants further investigation as a treatment in alcoholism.
A NEW SPECIES OF BACTRODESMIUM FROM WHITE SPRUCE
Authors: Sutton B. C.
Published: February 2008

Bactrodesmium obliquum n. sp. is described and illustrated from material on bark of Picea glauca (Moench) Voss collected in Manitoba and Saskatchewan. The species is characterized by punctiform, shining sporodochia and balastic, broadly oval, versicolored, 4-septate, dark-banded conidia, the apical and basal cells of which become obliquely or longitudinally septate. It is compared and contrasted with related species.
TISSUE CULTURE OF PINUS MONTICOLA ON A CHEMICALLY DEFINED MEDIUM
Authors: Harvey Alan E.
Published: February 2008

Procedures for obtaining and maintaining axenic tissue cultures of Pinus monticola are described. Western white pine tissue was cultured on a chemically defined medium containing calcium nitrate, magnesium sulfate, potassium phosphate (monobasic), ammonium sulfate, ferric sulfate, manganese sulfate, glucose, and one of three auxins, IAA, NAA, or 2,4-D. Addition of several B vitamins, amino acids, and kinetin increased growth on these media but were not required.
THE EFFECTS OF INDOLEACETIC ACID AND 2, 4-DICHLOROPHENOXYACETIC ACID ON INTERMEDIARY METABOLISM OF 14C-LABELLED ORGANIC ACIDS BY PEA ROOT TIPS
Authors: Kim W. K. , Bidwell R. G. S.
Published: February 2008

The effects of indoleacetic acid (IAA) and 2, 4-dichlorophenoxyacetic acid (2, 4-D) on the metabolism of 14C-specifically labelled pyruvic, acetic, succinic, and glutamic acids by pea root tips have been examined. The conversion of 14C from the substrates into alcohol-soluble and -insoluble fractions and respired CO2 was determined, and the radioactivity of certain soluble amino acids and organic acids was measured after chromatography. While pyruvic acid decarboxylation is unaffected, the carboxylation of pyruvic acid and the entry into the Krebs cycle of acetate derived from pyruvate is inhibited by the hormones. Acetate, however, is oxidized to CO2 much more rapidly in the presence of IAA or 2, 4-D. The accumulation of 14C in Krebs cycle intermediates or amino acids derived from them is prevented by the auxins. The results indicate that IAA and 2, 4-D have an inhibiting effect either on co-carboxylase or more likely on α-lipoic acid metabolism, but not on coenzyme A (CoA). Other specific effects on the metabolism of individual amino acids are also indicated.
A PACIFIC COAST SAXIFRAGE WITH 10 PAIRS OF CHROMOSOMES: MEIOSIS, DEVELOPMENT OF THE FEMALE GAMETOPHYTE, AND SEED PRODUCTION
Authors: Beamish Katherine I.
Published: February 2008

Saxifraga rufidula, variously classified as a species or as a variety or subspecies of S. occidentalis, has been studied in detail through meiosis, development of the female gametophyte, and seed production. Throughout the process it resembles closely the same process previously described for Saxifraga integrifolia. However, it lacks several unusual features of S. integrifolia. S. rufidula has 10 pairs of chromosomes, a fact which raises the question of its relationship to S. occidentalis (19 pairs of chromosomes) and to other, geographically distinct, 10-paired species.
DERMEA PSEUDOTSUGAE N. SP., A CAUSAL AGENT OF PHLOEM NECROSIS IN DOUGLAS FIR
Authors: Funk A.
Published: February 2008

A new species of Dermea is described. The fungus was associated with extensive damage to young Douglas fir (P seudotsuga menziesii) following severe early frosts in the Cariboo Region of British Columbia. Inoculation tests proved the fungus was capable of invading bark wounds and causing necrosis. Life history and cultural characteristics of the fungus are presented. The development of the disease is described and discussed.
STUDIES ON THE REGULATION OF CELLULASE ACTIVITY AND GROWTH IN EXCISED PEA EPICOTYL SECTIONS
Authors: Fan Der-Fong , Maclachlan G. A.
Published: February 2008

Applied indoleacetic acid (10−4 – 10−6 M) increased elongation and the amount and specific activity of cellulase in sections detached from the epicotyl of Pisum sativum L. var. Alaska. Actinomycin D (20 μg/ml) inhibited growth and the capacity of sections for synthesizing protein from absorbed 14C-leucine. At the same time it caused cellulase levels to decrease at a rate which indicated a half-life for the enzyme of less than 24 h. Pea cellulase was most stable in vitro between pH 6 and 7; at or below pH 5 its rate of denaturation was comparable to its turnover rate in vivo. Fractionation of sections yielded wall preparations which contained cellulase at a higher specific activity than particles or supernatant. It is concluded that cellulase is synthesized in excised sections by an auxin-regulated mechanism. It is proposed that the enzyme is transported to the wall where it may promote elongation and eventually become denatured.
INCORPORATION OF SERINE-14C AND ETHANOLAMINE-14C INTO NITROGEN-CONTAINING PHOSPHATIDES AND EFFECTS OF MEDIUM CONTAINING ETHANOLAMINE ON PHOSPHATIDE BIOSYNTHESIS IN EXCISED TOMATO ROOTS
Authors: Willemot Claude , Boll W. G.
Published: February 2008

Work was designed to study the decarboxylation of serine and biosynthesis of ethanolamine as part of an investigation into the replacement of vitamin B6by ethanolamine in the nutrition of excised tomato roots in sterile culture. A working hypothesis to explain the replacement involves repression, by ethanolamine, of a postulated vitamin B6dependent serine decarboxylase yielding ethanolamine.Evidence is presented, from studies using uniformly labelled serine-14C, serine-1-14C, serine-3-14C, and ethanolamine-1,2-14C (i) for the incorporation of serine and ethanolamine into the corresponding phosphatides, (ii) for the occurrence of a pathway whereby phosphatidyl serine is decarboxylated to phosphatidyl ethanolamine, which is further methylated to phosphatidyl choline, and (iii) for the existence of more than one molecular species of phosphatidyl ethanolamine.Experiments are reported in which uniformly labelled serine-14C was supplied in the presence and absence of the inhibitors ethionine, p-chloromercuribenzoate, or diethylethanolamine. The results suggest that in the excised tomato root a pathway of choline biosynthesis other than the phosphatide pathway may exist.Some evidence is given that the replacement of vitamin B6by ethanolamine decreases the decarboxylation of phosphatidyl serine.
INITIATION AND DEVELOPMENT OF ADVENTITIOUS ROOTS IN STEM CUTTINGS OF HEDERA HELIX: ANATOMICAL STUDIES OF THE JUVENILE GROWTH PHASE
Authors: Girouard Ronald M.
Published: February 2008

Anatomical studies were made of adventitious root formation in the internodes of cuttings from juvenile phase plants of Hedera helix, English ivy. Observations showed that adventitious roots originate in phloem ray parenchyma above the basal cuts within a period of 6–10 days. The actual emergence of the roots is at right angles to the main axis of the stems and the roots appear 10–14 days after the cuttings are made. Fibers are present in groups external and tangential to the phloem strands, but they do not inhibit development of the roots.
INITIATION AND DEVELOPMENT OF ADVENTITIOUS ROOTS IN STEM CUTTINGS OF HEDERA HELIX: ANATOMICAL STUDIES OF THE MATURE GROWTH PHASE
Authors: Girouard Ronald M.
Published: February 2008

Adventitious root formation was studied microscopically in stem cuttings of a difficult-to-root plant, the mature growth phase of Hedera helix, English ivy. Roots were found initiating at the end of 2–4 weeks in phloem ray parenchyma of internodes with and without woundwood and in callus near the basal end of cuttings; roots emerged at the end of 3–5 weeks. The fibro-bundle caps were thicker than those found in juvenile stems, but they did not hamper the development of adventitious roots.
CYTOTAXONOMY OF PHYSARIA ACUTIFOLIA, P. CHAMBERSII, AND P. NEWBERRYI (CRUCIFERAE)
Authors: Mulligan Gerald A.
Published: February 2008

The cytotaxonomy of three closely related species of Physaria (Nuttall) Gray is discussed. Each species has two or more chromosome races: P. acutifolia Rydberg, 2n = 8, 10, 16, and 24; P. chambersii Rollins, 2n = 8, 16, and 24; P. newberryi Gray, 2n = 8 and 16. Analyses of somatic karyotypes and meiotic configurations in first generation hybrids between diploids indicate that different species of Physaria are closely related chromosomally.
THE EFFECT OF SOIL MOISTURE ON THE GROWTH AND SPREAD OF CONIOPHORA PUTEANA UNDER LABORATORY CONDITIONS
Authors: Pentland Gertrude D.
Published: February 2008

The effect of soil moisture and the related effect of some soil-inhabiting microorganisms on the spread through soil of the root-rotting Basidiomycete Coniophora puteana were studied. A soil moisture level of 20%–25% saturation was satisfactory for the growth of C. puteana in non-sterile soil. The fungus was able to grow out from a small alder disc inoculum in the center of a petri dish and invade alder discs at the periphery of the dish. At 50% saturation and higher C. puteana was unable to grow out into the soil. In autoclaved soil the optimum moisture level for the growth of C. puteana was between 75% and 100% saturation.Small amounts of non-sterile soil were added to autoclaved soil at different moisture levels, with an effect on the growth of C. puteana similar to that of completely non-sterile soil. Trichoderma viride, a known antibiotic producer, was inoculated into autoclaved soil and produced a greater inhibition of C. puteana in the wetter treatments than in drier ones. The inhibitory effect of Acti-dione (cycloheximide), an antifungal antibiotic, was examined in autoclaved soil. The same concentration of antibiotic resulted in a greater inhibition of the growth of C. puteana at the higher moisture levels than at the lower ones. Some implications of the findings are discussed.
Growth stimulation of apple trees in unsterilized soil under field conditions with VA mycorrhiza inoculation
Authors: Plenchette Christian , Furlan Valentin , Fortin J. André
Published: February 2008

Apple seedlings germinated and grown under greenhouse conditions were inoculated with endomycorrhizal roots originating from a nursery grown Fraxinus prior to outplanting into unsterilized field soil. Uninoculated seedlings, in soil either unamended or amended with 100 kg/ha P as superphosphate, were controls. Shoot length, leaf surface, root volume, stem diameter, and dry mass of inoculated plants were all significantly greater than both fertilized and unfertilized controls. No significant difference could be observed in foliar mineral content but the level of N, P, Ca, Cu, and possibly K were higher in the roots of inoculated plants than in controls. Although shoot length of the phosphorus fertilized plants exceeded that of the unfertilized controls (p < 0.05), all the other growth parameters remained unchanged by the addition of P. Intracortical vesicles were absent or very uncommon in the roots of both fertilized and unfertilized control plants whereas they were very abundant in the roots of inoculated plants.It is concluded that inoculation of seedlings previous to field planting in unsterilized phosphorus-poor soil can lead to a significant growth stimulation in spite of the presence of a natural endomycorrhizal flora.
The ultrastructure of the central zone cells of the shoot apex of Helianthus annuus
Authors: Sawhney V. K. , Rennie P. J. , Steeves T. A.
Published: February 2008

An ultrastructural study of the vegetative shoot apex of Helianthus annuus L. cv. Peredovic has shown that in most respects the cytoplasmic components of the central zone cells were similar to those of the mitotically active peripheral zone cells. For example, the mitochondria, dictyosomes, endoplasmic reticulum, ribosomes, and microtubules were not different either in their structure or in distribution in the two types of cells. The only striking difference found was the presence of starch-containing plastids in the central zone, primarily in the two tunica layers in this region, and their absence from peripheral and immediately subjacent regions of the meristem. Starch-containing plastids were observed in the differentiating pith cells. Plasmodesmata were observed in the central zone and in walls between central and peripheral zone cells.
Salvinia leaves. III. Morphogenesis of the submerged leaf
Authors: Croxdale Judith G.
Published: February 2008

Submerged leaves in Salvinia arise as single cells from the shoot apex. Shortly after initiation the primordium appears as a conical group of cells with two areas of lateral expansion toward the base. These two lateral regions plus the abaxial surface between them are the sites of initial leaflet production in the primordium. Following the appearance of the first set of seven leaflets, an additional set of leaflets is initiated and they become apparent as the submerged leaf emerges from the terminal bud. The growth of the submerged leaf is protracted compared with the floating leaves of the same set. Compared with the precisely located abaxial meristems found in Salvinia floating leaves, no discrete, regularly positioned meristems occur in submerged leaves. Thus, developmentally these compound leaves have little in common with the floating leaves or with other highly divided leptosporangiate fern leaves. The development of the floating and submerged Salvinia leaves is discussed with respect to leaf development patterns of widespread distribution in higher plants.
The evolution of dinoflagellates
Authors: Bujak J. P. , Williams G. L.
Published: February 2008

Recent work on modern dinoflagellates indicates that these organisms occupy a critical position in the evolution of life, being intermediate between prokaryotes and eukaryotes. It further suggests that dinoflagellates acquired chloroplasts through symbiosis with ingested autotrophic organisms. Two models have been proposed to explain the development of the cellulosic theca in the Dinophyceae. The first, the plate increase model, is based primarily on observations of living algae, while the second, the plate reduction model, relies mainly on paleontological data. However, neither satisfactorily reconciles both lines of evidence and so the plate fragmentation model is proposed. This postulates that dinoflagellates with two anterior flagella and a wall consisting of two large valves were successful through much of the Paleozoic. A major evolutionary breakthrough occurred in the Triassic with the development of a transverse-longitudinal flagellar arrangement and change in swimming direction. Associated with these modifications was a fragmentation of the valves into numerous polygonal plates. Subsequent evolution emphasized the influence of the two flagellar furrows over the number and arrangement of thecal plates. This led to a decrease in number and stabilization of the thecal plates as seen in modern dinoflagellates.
Features of the inflorescence of Triglochin maritima
Authors: Charlton W. A.
Published: February 2008

The arrangement of floral primordia on the inflorescence has been examined in Triglochin maritima. Different inflorescences have spiral or multijugate forms of phyllotaxis. The inflorescence apex does not seem to give rise directly to a terminal flower, though floral primordia may ultimately arise on or very near the summit of the meristem. In the latter case a residual apex is left. These observations are combined with previous scattered data on the inflorescences of Triglochin. It is concluded that Triglochin inflorescences have a number of characters which are more usually associated with flowers.
Trichomaris invadens gen. et sp. nov., an ascomycete parasite of the tanner crab (Chionoecetes bairdi Rathbun Crustacea; Brachyura)
Authors: Hibbits Jolly , Hughes Gilbert C. , Sparks Albert K.
Published: February 2008

Trichomaris invadens Hibbits, Hughes and Sparks, gen. et sp. nov., an apparent obligate parasite of the tanner crab, Chionoecetes bairdi Rathbun, is described. This marine ascomycete is characterized by black, globose, aparaphysate perithecia borne on and in a subiculum of darkly pigmented encrusting hyphae on the exterior of the carapaces and appendages of host crabs; by two-celled ascospores bearing an unusually long, hairlike appendage at either end; and by internal hyphal invasion and destruction of host tissues following penetration of the carapace. Trichomaris invadens is the first pyrenomycete known to parasitize a marine crustacean. Observations on the pathogenicity of the fungus are included.
Pisolithus tinctorius forms long ectomycorrhizae and alters root development in seedlings of Pinus resinosa
Authors: Sohn Richard F.
Published: February 2008

Ectomycorrhizae were synthesized on Pinus resinosa seedlings with Pisolithus tinctorius under aseptic, controlled environmental conditions. Root systems were harvested at 4, 6, and 15 weeks after seed germination. All roots were classified as either long or short and were examined for ectomycorrhiza development. Mycorrhizae were classified as "long mycorrhizae" or "short mycorrhizae," depending upon the type of root where infection occurred.Long mycorrhizae predominated at the early harvests and remained prominent at 15 weeks. A Hartig net of long mycorrhizae formed a morphological continuum from thin to thick. Negative correlations were observed between long mycorrhiza growth rate and the extent of infection. This suggests that a threshold growth rate exists below which mycorrhiza formation occurs readily, but above which mycorrhiza formation is progressively diminished. Relative to the controls, P. tinctorius inoculation increased the ratio of second- and third-order short roots to long roots. The role of host and fungus in controlling lateral root development is discussed.
Low dosages of gamma irradiation of seed increase the growth and yield of two cultivars of sunflower
Authors: Shamsi S. R. A. , Roohi R. , Nisa A.
Published: February 2008

Seeds of cv. Restoler and Noor of sunflower (Helianthus annuus L.) were subjected to 0.5 to 50 krad 60Co gamma radiation (1 rad = 10 mGy) and grown to maturity in a greenhouse. Two low dosages, i.e., 1 krad in cv. Restoler and 3 krad in cv. Noor, caused statistically significant stimulation of vegetative growth and seed yield (both total number and weight). For cv. Noor, 3 krad also significantly stimulated the weight of an individual seed. Significant declines in the yield of mature seeds occurred only at critical dosages of > 10 to 20 krad.
Ultrastructure des ectomycorhizes synthétiques à Hebeloma alpinum et Hebeloma marginatulum de Dryas octopetala
Authors: Debaud J. C. , Pepin R. , Bruchet G.
Published: February 2008

Ectomycorrhizas of Dryas octopetala (Rosaceae) were synthesized with two alpine species of Hebeloma and observed by means of transmission electron microscopy. The mycorrhizas studied here were harvested at the time of fruiting of the associated fungi. The ultrastructure of the mycelial sheath, Hartig net, host cortical cells, and host–mycobiont interface was thus defined from very active, functional, living structures. Following analysis of the results, an interpretation of hyphal morphogenesis in the sheath and in the Hartig net is proposed.
The biological activity of ketogibberellin A1
Authors: Keith Brian , Srivastava Lalit M.
Published: February 2008

Ketogibberellin A1 has low to moderate biological activity in cucumber hypocotyl, lettuce hypocotyl, barley aleurone, and dwarf pea bioassays. As such, it may be a suitable analogue for competition studies involving gibberellin binding to receptor protein(s).
Use of plants for food and medicine by Native Peoples of eastern Canada
Authors: Arnason Thor , Hebda Richard J. , Johns Timothy
Published: February 2008

At least 175 food plants and 52 beverage plants were gathered by Native Peoples in eastern Canada. Iroquoian agriculturalists of southern Ontario cultivated corn, beans, squash, tobacco, and sunflowers, and gathered the greatest variety of food plants. Southern and eastern Algonkian hunters and gatherers ate a wide variety of wild plant foods including fleshy fruits, nuts, greens, and underground parts. Little is known about the use of wild food plants by northern Cree and Naskapi.Nutritional data for gathered plants indicate that many of these species exceed conventional plant sources for vitamins and minerals. Vitamin A, vitamin C, calcium, iron, and fibre are particularly well represented in certain gathered plants. Some wild plant foods require special preparation or must be consumed in limited quantities because they contain toxic secondary metabolites.Over 400 plants are used in native medicine. Native medicine consists of rational and ritualistic components. Treatment of physical disorders, whose origin could be determined, was effective. At least 105 medicinal plants have a real effectiveness based on phytochemical constituents. Conifers were the most widely used group of plants in this category. Antibiotic monoterpenes, polyacetylenes and alkaloids, astringent tannins, and analgesic monoterpenes and salicylates are among the most rationally and widely used plant constituents.There is need for more research into nutritional constituents and pharmacological properties to assess the value and potential of plants used by Native People of eastern Canada.
A gift for the taking: the untapped potential of some food plants of North American Native Peoples
Authors: Turner Nancy J.
Published: February 2008

Of all the plant species originating in North America north of Mexico and formerly used as food by Native Peoples, only one, the common sunflower (Helianthus annuus), has worldwide significance at present. A number of the small fruit species have been utilized by horticulturalists in developing varieties suitable for cultivation, and others (e.g., Helianthus tuberosus, Zizania aquatica, Acer saccharum) are utilized to some extent. For the most part, however, the value and potential of aboriginal food plants is not being realized. Some 100 species of native plants that could be utilized more fully in the diets of modern North Americans are listed, together with information on how and where they were used by Native Peoples. Many species would find wide acceptance in their present form if made available for marketing; others could be significantly improved through selection and hybridization. All could add variety, interest, and nutritional value to the modern diet. Potential problems involved in the adoption of such foods are discussed, and the advantages to be gained are outlined. Reinstatement of these foods among Native Peoples of North America is suggested as a way of restoring pride in native cultures as well as contributing significant nutritional and financial benefits.
AN ALTERNATING-SEQUENCE CONCEPTUAL FRAMEWORK FOR EIA-EMS INTEGRATION
Authors: PERDICOÚLIS ANASTÁSSIOS , DURNING BRIDGET
Published: February 2008

The integration of Environmental Impact Assessment (EIA) and Environmental Management Systems (EMS) has been approached several times in recent years. This article reviews existing conceptual frameworks and specific issues regarding the EIA-EMS integration, and recommends a new conceptual framework which is based on an alternating sequence of EMS and EIA. It also proposes adaptations in key documents of both processes. The recommendations are adaptable to the varied practice of EIA across the globe, and conform to the ISO14001-compliant EMS protocol.
A CASE STUDY IN PARTICIPATORY ENVIRONMENTAL SYSTEMS ASSESSMENT WITH THE USE OF MULTIMEDIA MATERIALS AND QUANTITATIVE LCA
Authors: SINCLAIR P. , COWELL S. , LÖFSTEDT R. , CLIFT R.
Published: February 2008

While participation in environmental decision-making is widely recognised and valued in democratic countries as beneficial, its format and scope have not always been the source of agreement. The use of environmental systems assessment (ESA) offers the opportunity for structuring knowledge and decision-making systematically and appropriately to decision makers' concerns, to enable lay publics to participate in development of policy and implementation in public sector initiatives. In order to perform participatory ESA, effective means of involving lay people are required. This paper describes the development and testing of an innovative interactive multimedia package (WOMBLE), written for non-experts to enable them to use the expert tool WISARD, a quantitative life cycle assessment package, to enable involvement in developing and assessing options for management of Municipal Solid Waste (MSW). It was shown that this combination of tools can reduce the time needed to achieve effective communication, learning and active engagement.
Quantitative cellular description of gastric slow wave activity
Authors: Corrias Alberto , Buist Martin L.
Published: February 2008

Interstitial cells of Cajal (ICC) are responsible for the spontaneous and omnipresent electrical activity in the stomach. A quantitative description of the intracellular processes whose coordinated activity is believed to generate electrical slow waves has been developed and is presented here. In line with recent experimental evidence, the model describes how the interplay between the mitochondria and the endoplasmic reticulum in cycling intracellular Ca2+provides the primary regulatory signal for the initiation of the slow wave. The major ion channels that have been identified as influencing slow wave activity have been modeled according to data obtained from isolated ICC. The model has been validated by comparing the simulated profile of the slow waves with experimental recordings and shows good correspondence in terms of frequency, amplitude, and shape in both control and pharmacologically altered conditions.
Disturbances of colonic motility in mouse models of Hirschsprung's disease
Authors: Roberts Rachael R. , Bornstein Joel C. , Bergner Annette J. , Young Heather M.
Published: February 2008

Mutations in genes encoding members of the GDNF and endothelin-3 (Et-3) signaling pathways can cause Hirschsprung's disease, a congenital condition associated with an absence of enteric neurons in the distal gut. GDNF signals through Ret, a receptor tyrosine kinase, and Et-3 signals through endothelin receptor B (Ednrb). The effects of Gdnf, Ret, and ET- 3 haploinsufficiency and a null mutation in ET- 3 on spontaneous motility patterns in adult and developing mice were investigated. Video recordings were used to construct spatiotemporal maps of spontaneous contractile patterns in colon from postnatal and adult mice in vitro. In Ret+/−and ET- 3+/−mice, which have normal numbers of enteric neurons, colonic migrating motor complexes (CMMCs) displayed similar properties under control conditions and following inhibition of nitric oxide synthase (NOS) activity to wild-type mice. In the colon of Gdnf+/−mice and in the ganglionic region of ET- 3−/−mice, there was a 50–60% reduction in myenteric neuron number. In Gdnf+/−mice, CMMCs were present, but abnormal, and the proportion of myenteric neurons containing NOS was not different from that of wild-type mice. In the ganglionic region of postnatal ET- 3−/−mice, CMMCs were absent, and the proportion of myenteric neurons containing NOS was over 100% higher than in wild-type mice. Thus impairments in spontaneous motility patterns in the colon of Gdnf+/−mice and in the ganglionic region of ET- 3−/−mice are correlated with a reduction in myenteric neuron density.
Estrogen, medroxyprogesterone acetate, endothelial function, and biomarkers of cardiovascular risk in young women
Authors: Meendering Jessica R. , Torgrimson Britta N. , Miller Nicole P. , Kaplan Paul F. , Minson Christopher T.
Published: February 2008

Medroxyprogesterone acetate (MPA) is widely known for its use in combination hormone therapy for postmenopausal women. However, MPA is also commonly used in young women for contraception and treatment of a number of gynecological conditions. Despite its widespread use, the cardiovascular effects of MPA in young women are unclear. Therefore, the purpose of this study was to determine the acute effects of MPA when used in combination with estradiol on markers of cardiovascular risk in young women. We suppressed endogenous estrogens and progesterone in 10 premenopausal women using a gonadotropin-releasing hormone antagonist (GnRHa) for 10 days. On day 4 of GnRHa subjects received 0.1 mg of estradiol (GnRHa+E2), and on day 7 5 mg of MPA was added (GnRHa+E2+MPA). Endothelium-dependent vasodilation and endothelium-independent vasodilation of the brachial artery, lipids, homocysteine, high-sensitivity C-reactive protein, and endothelin-1 were assessed during treatment with GnRHa, GnRHa+E2, and GnRHa+E2+MPA. Four additional subjects were tested to validate the efficacy of the GnRHa model and confirm the findings. Endothelium-dependent vasodilation was greater during GnRHa+E2 than during GnRHa or GnRHa+E2+MPA ( P = 0.006). Endothelin-1 was lower during GnRHa+E2 than GnRHa alone ( P = 0.039). Endothelin-1 increased with the addition of MPA and was not significantly different from GnRHa alone. There were no differences in the other markers of cardiovascular risk between hormone treatment days. These data suggest that acute MPA administration negates the beneficial effects of estradiol on endothelium-dependent vasodilation in young women. In addition, these data suggest that estradiol decreases endothelin-1 concentrations and the addition of MPA may counteract the effect of estradiol on endothelin-1.
Neutrophil accumulation following passive stretches contributes to adaptations that reduce contraction-induced skeletal muscle injury in mice
Authors: Lockhart Nicole C. , Brooks Susan V.
Published: February 2008

Skeletal muscles can be injured by their own contractions, especially when the muscle is stretched during a lengthening contraction. Exposing a muscle to a conditioning protocol of stretches without activation (passive stretches) before lengthening contractions reduces contraction-induced injury. Although passive stretching does not damage muscle fibers, neutrophils are elevated in the muscle after passive stretches. Our purpose was to investigate the relationship between neutrophil accumulation following passive stretches and the protection from subsequent contraction-induced injury provided by the passive stretches. Our hypothesis was that passive stretch conditioning would not provide protection from subsequent lengthening contraction-induced injury under circumstances when the increase in muscle neutrophils in response to the conditioning was prevented. Extensor digitorum longus muscles of mice were conditioned with passive stretches 14 days before exposure to a protocol of damaging lengthening contractions. Mice were either untreated or treated with an antibody (RB6-8C5) that reduced the level of circulating neutrophils by over 95% before administration of passive stretches. Neutrophil levels recovered in treated mice by the time lengthening contractions were performed. Lengthening contractions were also administered to muscles with no prior exposure to passive stretches. Maximum isometric force, number of damaged fibers, and muscle neutrophil concentration were measured 3 days after lengthening contractions. Compared with nonconditioned control muscles, the severity of contraction-induced injury was not reduced by prior passive stretch conditioning when mice were treated with RB6-8C5 before conditioning. We conclude that neutrophils contribute to adaptations that protect muscles from injury.