bluuebunny/crossref_metadata_2025 huggingface dataset:
Feature profile evolution during shallow trench isolation etch in chlorine-based plasmas. I. Feature scale modeling
Authors: Hoang John , Hsu Cheng-Che , Chang Jane P.
Published: December 2008

The authors developed a cellular based Monte Carlo (MC) feature scale model capable of direct coupling to the dominant plasma species ratios from a reactor scale model in order to simulate the profile evolution of shallow trench isolation etch in chlorine-based plasmas and its variation from the center to the edge of the wafer. Carefully planned experiments along with scanning electron microscopy (SEM) were used to calibrate the MC model, where one to two plasma parameters were systematically varied. Simulated feature profiles were found to agree well with experimental observations, capturing details such as microtrenching, faceting, tapering, and bowing. The particle counts used to achieve these fits agreed well with those estimated from SEM, corroborating the chemistry and physics used in the feature scale model. In addition, the feature scale model uses a novel surface representation that eliminates the artificial flux fluctuations originating from the discrete cells used in the simulation and enables a much more precise calculation of the surface normal, which dictates the trajectory of reflected species.
X-ray diffraction microscopy: Reconstruction with partial magnitude and spatiala prioriinformation
Authors: Baghaei Rad Leili , Downes Ian , Dai Bing , Zhu Diling , Scherz Andreas , Ye Jun , Pianetta Piero , Fabian W. Pease R.
Published: December 2008

The goal is to nondestructively reconstruct the structure of a fabricated integrated circuit using x-ray diffraction measurement. In particular, to detect any deviation from the specification of the circuit design. Determining phase is critical. However, additional information exists as the phase of the design specification is known. Further phase information is determined by oversampling and a better estimate of the correct phase is obtained through convex optimization. The authors illustrate this technique with a simulated one dimensional example and a simple two dimensional experimental sample.
Actinic extreme ultraviolet mask inspection beyond 0.25numericalaperture
Authors: Goldberg K. A. , Naulleau P. , Mochi I. , Anderson E. H. , Rekawa S. B. , Kemp C. D. , Gunion R. F. , Han H.-S. , Huh S.
Published: December 2008

The SEMATECH Berkeley actinic inspection tool (AIT) is an extreme ultraviolet (EUV)-wavelength mask inspection microscope designed for direct aerial image measurements and precommercial EUV mask research. Operating on a synchrotron bending magnet beamline, the AIT uses an off-axis Fresnel zoneplate lens to project a high-magnification EUV image directly onto a charge coupled device camera. The authors present the results of recent system upgrades that have improved the imaging resolution, illumination uniformity, and partial coherence. Benchmarking tests show image contrast above 75% for 100nm mask features and significant improvements and across the full range of measured sizes. The zoneplate lens has been replaced by an array of user-selectable zoneplates with higher magnification and numerical aperture (NA) values up to 0.0875, emulating the spatial resolution of a 0.35NA 4× EUV stepper. Illumination uniformity is above 90% for mask areas 2μm wide and smaller. An angle-scanning mirror reduces the high coherence of the synchrotron beamline light source giving measured σ values of approximately 0.125 at 0.0875NA.
Extreme ultraviolet lithography: Status and prospects
Authors: Benschop Jos , Banine Vadim , Lok Sjoerd , Loopstra Erik
Published: December 2008

Extreme ultraviolet lithography (EUVL) using 13.5nm wavelength light is the leading candidate to succeed 193nm immersion lithography, enabling semiconductor chips with features smaller than 22nm. Several major programs worldwide have developed this technology in recent years [D. A. Tichenor et al., OSA Proceedings on Soft X-Ray Projection Lithography, edited by A. M. Hawryluk and R. H. Stuten (1993), Vol. 18, p. 79; H. Kinachita, OSA Proceedings on Soft X-Ray Projection Lithography, edited by A. M. Hawryluk and R. H Stulen (1993), Vol. 18, p. 74; J. P. H. Benschop, W. M. Kaiser, and D. C. Ockwell, Proc. SPIE 3676, 246 (1999)] and in 2006, ASML shipped the first EUV Alpha Demo tools (NA=0.25 full-field scanners) to IMEC in Belgium [A. M. Goethals et al., Proc. SPIE 6517, 651709 (2007)] and CNSE in Albany [O. Wood et al., Proc. SPIE 6517, 6517–041 (2007)], USA. Currently the development of preproduction tools with targeted shipment of 2009 is well under way. This paper discusses the most critical items for EUVL development, namely, EUV imaging and EUV sources. Furthermore, it elaborates on the necessary development of masks and resists and, for example, quantifies how resist diffusion length can impact imaging capabilities. Results obtained and lessons learned with the Alpha Demo tools are discussed, as well as potential solutions to some of the remaining challenges. Additionally, this paper explains how EUV can realize high productivity (>100wafers∕h) and high resolutions (<22nm) to continue the cost-effective shrink of semiconductors for several generations.
An innovative design of wafer height and tilt sensor for lithography systems
Authors: Ruan Junru , Hartley John
Published: December 2008

Since lithography systems have limited depth of focus, precise and real-time measurement of wafer height is important for the image quality control. The traditional grazing incidence height sensor for lithography system consists of two basic components: a light source to illuminate the wafer surface and a detection surface to receive the reflected light beam from the wafer. Mathematical study of this type of height sensor shows that they will fail to differentiate the height difference of the wafer from the tilt of the wafer. In order to obtain the tilt information, height sensors with more complicated designs are used, and examples of these designs are briefly reviewed. A new design for a wafer height sensor is proposed here. By adding an independent detection surface, the new design is able to obtain wafer height and tilt information without using a complicated optical design, which results in easy alignment and calibration.
Quality assessment of antisticking layers for thermal nanoimprint
Authors: Scheer H.-C. , Häfner W. , Fidler A. , Möllenbeck S. , Bogdanski N.
Published: December 2008

Layers from fluorinated trichlorosilanes are in widespread use for the prevention of sticking in nanoimprint. It is generally assumed that these layers are monolayers, bonded to the substrate, and internally cross-linked. The authors have investigated a gas phase deposition process for such layers in detail, varying the amount of antisticking agent and the deposition time in a vacuum process. The quality of the layers was determined from the layer thickness and the contact angle was measured. In accordance with some recent literature, claiming that formation of dense cross-linked monolayers from fluorocarbon-trichlorosilanes is not possible, the results indicate that the deposited layers are not monolayers. Instead the authors suggest that they are even thinner disordered but cross-linked layers. Obviously monolayer formation is not required for sticking prevention.
Pulsed laser techniques for nanographoepitaxy
Authors: Crnogorac F. , Witte D. J. , Pease R. F. W.
Published: December 2008

Graphoepitaxy is a technique that has been demonstrated as a means for fashioning regions of single crystal semiconductors on amorphous substrates. In that earlier work the heating period was long (1s or more) and the substrate needed to be held close to the melting point of the semiconductor. With a view to achieving three-dimensional integrated circuits, the authors have investigated the possibility using graphoepitaxy to yield device quality single crystal islands of silicon on an amorphous substrate without excessive heating of the underlying layers by using transient (<1ms) heating. A stationary laser pulse of 532nm wavelength, 100μs duration, and 22μm diameter impinged on a 50nm thick amorphous silicon film deposited on 12nm thick SiO2 inverted pyramid template. We demonstrated successful graphoepitaxial orientation of crystallized silicon but only under conditions that gave excessive heating (>400°C) of lower layers, thus indicating that this technique is impractical for three-dimensional integrated circuits.
Comparison of monomer and polymer resists in thermal nanoimprint lithography
Authors: Zelsmann M. , Perez Toralla K. , De Girolamo J. , Boutry D. , Gourgon C.
Published: December 2008

In this article, the authors compare a polymer resist to a thermally curable monomer resist in a full 8in. wafer thermal nanoimprint lithography process. Using exactly the same imprinting conditions, the authors compare the printing quality and investigate the resist distribution through large area gratings (6×6mm2) with various densities. It is shown that a liquid monomer solution greatly enhance the printing uniformity because of a much wider resist redistribution and flow during the process. Redistribution of the monomer resist is observed over an entire grating, while it is observed only over a few periods of a grating for the polymer in the same conditions. Furthermore, a low molecular weight resist allows reducing the imprinting force as well as the total cycle time.
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photoconductor structures at 1.55μm: From advanced materials to prototype devices
Authors: Roucka R. , Xie J. , Kouvetakis J. , Mathews J. , D’Costa V. , Menéndez J. , Tolle J. , Yu S.-Q.
Published: December 2008

Prototype detector structures were fabricated on Si substrates using Ge1−ySny as active material for the first time. This alloy system covers the entire near-IR telecommunication spectrum and grows at a low temperature of 350°C, compatible with complementary metal-oxide-semiconductor (CMOS) Si technology. Processing protocols were developed for photolithography-based patterning and subsequent etching, CMOS compatible metallization, and for the formation of low-resistivity Ohmic contacts. A first generation of devices based on as-grown Ge1−ySny layers was followed by a second generation incorporating ex situ rapid thermal annealing for defect reduction, as well as additional growth and processing improvements, leading to enhanced mobilities and simultaneous reduction in intrinsic carrier concentrations. While both device generations show a significant photoconductive response at 1.55μm, the thicker second-generation samples yield improved performance due to better confinement of deleterious defects near the interface, which increases the optically active fraction of the film.
Engineering surface plasmon grating couplers through computer simulation
Authors: Ceperley Daniel P. , Neureuther Andrew R.
Published: December 2008

Surface plasmon grating couplers are optimized by separately characterizing the collection efficiency, rescattering, and transmission effects of isolated grating elements with finite difference time domain methods and then using signal flow graph methods to assess the performance of arrays of N identical elements. Small bars, ridges, and trenches on silver at a wavelength of 700nm are shown to have different coupling patterns and efficiencies from near zero to the physical width of the element. The overall efficiency requires a suitable trade-off of coupling and surface wave transmission and an example structure exhibiting an equivalent 100% capture length over ten wavelengths is shown.
Categorization of problems to assess and improve proficiency as teachers and learners
Authors: Singh Chandralekha
Published: December 2008

We describe how graduate students categorize introductory mechanics problems based on the similarity of their solutions. Graduate students were asked at the end of a teaching assistant training class to categorize problems from their own perspective and from the perspective of typical introductory physics students whom they were teaching. We compare their categorizations with the categorizations by introductory physics students and physics faculty who categorized the same problems. The utility of categorization as a tool for teaching assistant training and faculty development workshops is discussed.
Electrochemical Properties of Surface-Fluorinated Vapor Grown Carbon Fiber for Lithium Ion Battery
Authors: Nakajima Tsuyoshi , Hashimoto Ken-ichi , Achiha Takashi , Ohzawa Yoshimi , Yoshida Akira , Mazej Zoran , Žemva Boris , Lee Young-Seak , Endo Morinobu
Published: December 2008

Surface fluorination of graphitized vapor grown carbon fiber (VGCF) has been performed with F2, F2-O2, NF3 or ClF3 under mild conditions. Charge/discharge characteristics were investigated in 1 mol/l LiClO4-ethylene carbonate (EC)/diethyl carbonate (DEC) and EC/DEC/ propylene carbonate (PC) solutions. The main effect of surface fluorination was increase in charge capacities. The increase in charge capacities was larger for VGCF fluorinated with ClF3 or NF3 than F2 or F2-O2. The reason is that the fluorination reactions of graphite with ClF3 and NF3 are radical reactions having surface etching effect, effectively breaking cylindrically rolled graphene layers of VGCF.
Michael Addition Reactions to 3-(4-Chloro-4,4-difluorobut-2-enoyl)oxazolidin-2-one
Authors: Fukuda Miyako , Kawasaki-Takasuka Tomoko , Yamazaki Takashi
Published: December 2008

1,4-Addition reactions to chlorodifluorinated Michael acceptor 1b containing a chiral oxazolidinone auxiliary were found to proceed smoothly either with alkyllithium or Grignard reagents in the presence of CuY (Y = I or CN) or ZnCl2. In contrast to the corresponding cuprates, R2Zn or R3ZnMgBr species (prepared from 2 or 3 equiv. of RMgX and ZnCl2, respectively) were quite effective in suppression of the unfavorable β-elimination mechanism leading to the terminally difluorinated byproduct 3.
Octafluoro[2.2]paracyclophane (AF4) Quinone
Authors: Xu Wei , Dolbier William R. , Duan Jian-Xin , Zhai Yian , Ogawa Katsu , Battiste Merle A. , Ghiviriga Ion
Published: December 2008

Octafluoro[2.2]paracyclophane (AF4) has been oxidized by treatment with HIO3 in CF3CO2H to form the corresponding p-quinone along with a unique triketone. This quinone undergoes reduction to the respective hydroquinone as well as a Diels-Alder reaction with 1,3-cyclohexadiene. Its reduction potential was obtained by cyclic voltammetry and is discussed in the context of other quinones.
Mental health in an age of celebrity: the courage to care
Authors: Barker P , Buchanan-Barker P
Published: December 2008

Modern psychiatry, which once focused only on the containment and “cure” of madness, has evolved into a mental health industry, where almost every aspect of human life, may be cast as a “mental disorder”. In Western countries, a narcissistic appetite for self-improvement and “well-being” has evolved over the past 50 years, mirroring the emergence of the celebrity culture. These developments appear linked to a fading of interest in the traditional concept of human caring, leading to a further marginalisation of people with serious “mental health problems” and to increased use of authoritarian forms of control and containment. In this paper, the idea of vocation in the field of mental health is explored. Whatexactlyare we called to do aspeople—whether as professionals, friends or fellow travellers—when someone experiences a significant problem in human living?
Structural and metamorphic relationships between the Mount Ida and Monashee Groups at Mara Lake, British Columbia
Authors: Nielsen Kent C.
Published: December 2008

Mara Lake, British Columbia straddles the boundary between the Monashee Group on the east and the Mount Ida Group on the west. Correlation of units across the southern end of Mara Lake indicates lithologic continuity between parts of the groups. Both groups have experienced four phases of deformation. Phases one and two are tight and recumbent, trending to the north and to the west, respectively. Phases three and four are open to closed and upright, trending northwest and northeast, respectively. Second-phase deformation includes large-scale tectonic slides that separate areas of consistent vergence. Slide surfaces are folded by third- and fourth-phase structures and outline domal outcrop patterns. Metamorphic grade increases from north to south along the west side of Mara Lake. Calc-silicate reactions involving the formation of diopside are characteristic. From west to east increasing grade is evident in the reaction of muscovite + quartz producing sillimanite + K-feldspar + water. These prograde reactions are related to relative position in the second-phase structure. The highest grade is located near the lowest slide surface. Greenschist conditions accompanied phase-three deformation. Fourth phase is characterized by hydrothermal alteration, brittle fracturing, and local faulting. First-phase deformation appears to be pre-Late Triassic whereas second and third phases are post-Late Triassic and pre-Cretaceous. The fourth phase is part of a regional Tertiary event. The third folding event is correlated with the development of the Chase antiform and the second-phase folding is related to the pervasive east–west fabric of the Shuswap Complex. The timing of these events indicates that the metamorphic core zone of the eastern Cordillera was relatively rigid during the late Mesozoic foreland thrust development. Ductile deformation significantly preceded thrusting and developed a fabric almost at right angles to the trend of the thrust belt.
Hendrik Peter Bernelot Moens (1931–2008)
Authors: Marcon Edyta
Published: December 2008

The synaptonemal complex (SC) is a proteinaceous structure that physically holds the two homologous chromosomes together during meiotic prophase. First observed in 1956 by Montrose J. Moses (Duke University, Durham, North Carolina) in meiotic prophase spermatocytes of crayfish, the SC was found in many other species. Initially, the research into the SC focused on its structural characteristics, but with the availability of antibodies, the focus shifted to the protein components of the complex, and later, attention was diverted to the proteins associated with this structure at different time points during meiotic prophase. Various possible roles of this meiotic-specific structure have been debated since the discovery of the SC structure but consensus has yet to be reached. Dr. Peter Moens has been an internationally recognized expert on the SC, being involved in all of the steps and characterizing many of the structural and functional components of the complex mainly in mice but also in other species.
The Bo1-specific PCR marker AWW5L7 is predictive of boron tolerance status in a range of exotic durum and bread wheats
Authors: Schnurbusch Thorsten , Langridge Peter , Sutton Tim
Published: December 2008

High soil boron (B) constitutes a major soil problem in many parts of the world, particularly in low-rainfall areas and land under irrigation. Low accumulation of B in the shoot or grain of cereal crops is correlated with the maintenance of biomass production and grain yield under high B conditions, suggesting that this trait is an important component of field tolerance. A novel screening protocol to measure B accumulation in aerated and supported hydroponics was validated using a set of known and exotic bread wheat ( Triticum aestivum L.) and durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husn.) accessions. Furthermore, B accumulation in two Triticum urartu Tumanian ex Gandilyan and 54 Triticum monococcum L. accessions was measured and showed considerable phenotypic variation. However, B accumulation in these lines was higher than that observed in the most tolerant durum or bread wheats. Mapping of high B tolerance in the durum population AUS14010/Yallaroi revealed a locus possibly allelic to Bo1, a major source of B toxicity tolerance previously identified in bread wheat. Here, we show that the Bo1-specific codominant PCR marker AWW5L7 is predictive of B tolerance status among exotic durum and bread wheat accessions. All tolerant durum accessions assayed carried very similar AWW5L7 marker fragments, indicating wide distribution of this allele among tolerant durum wheats. Three bread wheat accessions had tolerance that was independent of Bo1 and is probably located on chromosome 4A. These lines represent a valuable genetic resource for B toxicity tolerance breeding in wheat.
The effect of transposonPokeyinsertions on sequence variation in the 28S rRNA gene ofDaphnia pulex
Authors: Glass Shiona K. , Moszczynska Anna , Crease Teresa J.
Published: December 2008

The goal of this study was to determine the impact of breeding system and the presence of the transposon Pokey on intraindividual variation in 28S rRNA genes. We PCR-amplified, cloned, and sequenced 1000 nucleotides downstream of the Pokey insertion site in genes with and without insertions from 10 obligately and 10 cyclically parthenogenetic isolates of Daphnia pulex. Variation among genes with Pokey insertions was higher than variation among genes without insertions in both cyclic and obligate isolates. Although the differences were not quite significant (p = 0.06 in both cases), the results suggest that Pokey insertions are likely to inhibit the homogenization of their host genes to some extent. We also observed that the complement of 28S rRNA alleles differed between genes with and without inserts in some isolates, suggesting that a particular inserted gene can persist for substantial periods of time and even spread within the rDNA array, despite the fact that insertions are deleterious. This apparently contradictory pattern can be explained if homogenization of rRNA genes occurs primarily by gene conversion, but copies with Pokey inserts can occasionally increase in frequency within arrays owing to unequal crossing over events that do not originate in the inserted genes themselves.
A new gene for resistance to Dysaphis pyri in pear and identification of flanking microsatellite markers
Authors: Evans Kate M. , Govan Ceri L. , Fernández-Fernández Felicidad
Published: December 2008

Dysaphis pyri is an important aphid pest of European pear ( Pyrus communis ) cultivars, none of which are currently reported to be resistant. In this study, we produced a progeny of the European pear Comice crossed with an accession of snow pear (Pyrus nivalis) that segregated for resistance to D. pyri in a Mendelian fashion, indicating the presence of a major gene, Dp-1. Following screening of the parents and seedlings with microsatellite markers, cosegregation analysis indicated that Dp-1 is flanked by NH006b and NH014a on linkage group 17, 2.3 and 3.6 cM away, respectively. Evidence is also presented for the duplication of linkage groups 9 and 17, which is a consequence of the allopolyploid origin of pear.
Plasma deuterium oxide accumulation following ingestion of different carbohydrate beverages
Authors: Currell Kevin , Urch Joanna , Cerri Erika , Jentjens Roy L.P. , Blannin Andy K. , Jeukendrup Asker E.
Published: December 2008

Optimal fluid delivery from carbohydrate solutions such as oral rehydration solutions or sports drinks is essential. The aim of the study was to investigate whether a beverage containing glucose and fructose would result in greater fluid delivery than a beverage containing glucose alone. Six male subjects were recruited (average age (±SD): 22 ± 2 y). Subjects entered the laboratory between 0700h and 0900h after an overnight fast. A 600 mL bolus of 1 of the 3 experimental beverages was then given. The experimental beverages were water (W), 75 g glucose (G), or 50 g glucose and 25 g fructose (GF); each beverage also contained 3.00 g of D2O. Following administration of the experimental beverage subjects remained in a seated position for 180 min. Blood and saliva samples were then taken every 5 min in the first hour and every 15 min thereafter. Plasma and saliva samples were analyzed for deuterium enrichment by isotope ratio mass spectrometry. Deuterium oxide enrichments were compared using a 2-way repeated measures analysis of variance. The water trial (33 ± 3 min) showed a significantly shorter time to peak than either G (82 ± 40 min) or GF (59 ± 25 min), but the difference between G and GF did not reach statistical significance. There was a significantly greater AUC for GF (55 673 ± 10 020 δ‰ vs. Vienna Standard Mean Ocean Water (VSMOW).180min) and W (60 497 ± 9864 δ‰ vs. VSMOW.180min) compared with G (46 290 ± 9622 δ‰ vs. VSMOW.180min); W and GF were not significantly different from each other. These data suggest that a 12.5% carbohydrate beverage containing glucose and fructose results in more rapid fluid delivery in the first 75 min than a beverage containing glucose alone.
Obésité et modernité : l’émergence de nouveaux stimuli nous amène-t-elle à redéfinir la notion de sédentarité?
Authors: Chaput Jean-Philippe
Published: December 2008

La mondialisation des marchés impose une pression accrue envers la performance, la productivité et la profitabilité des entreprises. Cette nouvelle réalité se traduit, entre autres, par une accentuation du travail du savoir ainsi que par une diminution du temps passé au lit. De plus, l’activité physique peut être considérée à juste titre comme une composante du mode de vie qui a été malheureusement laissée de côté et qui doit être minimalement réinsérée dans les activités de tous les jours. En effet, l’activité physique est porteuse d’une stimulation corporelle qui affecte significativement le bilan d’énergie et qui favorise sa bonne régulation. De leur côté, le travail mental et le manque de sommeil ont le potentiel de favoriser le surpoids. En effet, les résultats présentés dans cette thèse montrent que le manque de sommeil est prédicteur du surpoids et du gain de poids à long terme et est associé au diabète de type 2 chez les adultes. De plus, nous avons observé que le travail mental est déstabilisant pour l’homéostasie hormonale et peut être considéré comme un stimulus aux propriétés hyperphagiantes. Or, le manque de sommeil et le travail du savoir, deux modalités qui sont l’apanage du monde moderne, soulèvent de nombreuses questions face à notre compréhension de l’étiologie de l’obésité. En effet, leurs caractéristiques biologiques propres nous amènent non seulement à redéfinir la notion de sédentarité, mais à reconsidérer nos valeurs sociétales dans un contexte où l’aspect pécunier a primauté sur la santé. En outre, nos recherches ont montré que la perte pondérale dépassant 10 % du poids initial a le potentiel d’affecter négativement la santé mentale, compliquant ainsi la prise en charge de l’obésité. À la lumière de ces recherches doctorales, il apparaît évident que l’obésité est une condition complexe de par son caractère multifactoriel qui complique sa prévention et son traitement. De plus, la notion « d’équilibre » semble être une des clefs du succès, alors qu’une dominance de facteurs « obésogènes » caractérise le quotidien des individus, altérant ainsi la bonne régulation du bilan d’énergie. Cette nouvelle réalité peut également faire en sorte que le gain de graisse devienne nécessaire afin de maintenir l’homéostasie psychobiologique dans pareil contexte, considérant que le gain de graisse a le potentiel de restaurer l’équilibre hormonal qui a été déstabilisé par les stimuli de l’ère moderne.
High-intensity aerobic interval training increases fat and carbohydrate metabolic capacities in human skeletal muscle
Authors: Perry Christopher G.R. , Heigenhauser George J.F. , Bonen Arend , Spriet Lawrence L.
Published: December 2008

High-intensity aerobic interval training (HIIT) is a compromise between time-consuming moderate-intensity training and sprint-interval training requiring all-out efforts. However, there are few data regarding the ability of HIIT to increase the capacities of fat and carbohydrate oxidation in skeletal muscle. Using untrained recreationally active individuals, we investigated skeletal muscle and whole-body metabolic adaptations that occurred following 6 weeks of HIIT (~1 h of 10 × 4 min intervals at ~90% of peak oxygen consumption (VO2 peak), separated by 2 min rest, 3 d·week–1). A VO2 peaktest, a test to exhaustion (TE) at 90% of pre-training VO2 peak, and a 1 h cycle at 60% of pre-training VO2 peakwere performed pre- and post-HIIT. Muscle biopsies were sampled during the TE at rest, after 5 min, and at exhaustion. Training power output increased by 21%, and VO2 peakincreased by 9% following HIIT. Muscle adaptations at rest included the following: (i) increased cytochrome c oxidase IV content (18%) and maximal activities of the mitochondrial enzymes citrate synthase (26%), β-hydroxyacyl-CoA dehydrogenase (29%), aspartate-amino transferase (26%), and pyruvate dehydrogenase (PDH; 21%); (ii) increased FAT/CD36, FABPpm, GLUT 4, and MCT 1 and 4 transport proteins (14%–30%); and (iii) increased glycogen content (59%). Major adaptations during exercise included the following: (i) reduced glycogenolysis, lactate accumulation, and substrate phosphorylation (0–5 min of TE); (ii) unchanged PDH activation (carbohydrate oxidation; 0–5 min of TE); (iii) ~2-fold greater time during the TE; and (iv) increased fat oxidation at 60% of pre-training VO2 peak. This study demonstrated that 18 h of repeated high-intensity exercise sessions over 6 weeks (3 d·week–1) is a powerful method to increase whole-body and skeletal muscle capacities to oxidize fat and carbohydrate in previously untrained individuals.
Validation of the Kenz Lifecorder EX and ActiGraph GT1M accelerometers for walking and running in adults
Authors: Abel Mark G. , Hannon James C. , Sell Katie , Lillie Tia , Conlin Geri , Anderson David
Published: December 2008

Accelerometer-based activity monitors are commonly used by researchers and clinicians to assess physical activity. Recently, the Kenz Lifecorder EX (KL) and ActiGraph GT1M (AG) accelerometers have been made commercially available, but there is limited research on the validity of these devices. Therefore, we sought to validate step count, activity energy expenditure (EE), and total EE output from the KL and AG during treadmill walking and running. Ten male and 10 female participants performed 10 min treadmill walking and running trials, at speeds of 54, 80, 107, 134, 161, and 188 m·min–1. Step counts were hand tallied by 2 observers, and indirect calorimetry was used to validate the accelerometers’ estimates of EE. AG total EE was calculated using the Freedson equation. Analysis of variance (ANOVA) and Pearson’s correlations were used to analyze the data. At the slowest walking speed, the AG and KL counted 64% ± 15% and 92% ± 6% of the observed steps, respectively. At all other treadmill speeds, both activity monitors undercounted, compared with observed steps, by ≤3%. The KL underestimated activity EE at faster running speeds (p < 0.01), overestimated total EE at some walking speeds, and underestimated total EE at some running speeds (p < 0.01). The Freedson equation inaccurately measured total EE at most walking and running speeds. The KL and the AG are moderately priced accelerometers that provide researchers and clinicians with accurate estimates of step counts and activity EE at most walking and running speeds.
Progesterone and estrogen influence postexercise leukocyte infiltration in overiectomized female rats
Authors: Iqbal Sobia , Thomas Amy , Bunyan Kareem , Tiidus Peter M.
Published: December 2008

Limited research has been conducted on the effects of progesterone alone, or in combination with estrogen, on leukocyte infiltration in skeletal muscle following exercise. To investigate the effects of these female sex hormones, ovariectomized female rats were divided into 4 exercise and 4 control groups: sham, estrogen, progesterone, and a combination of estrogen plus progesterone. Following 8 days of hormone replacement and 24 h postexercise, soleus (red) and superficial (white) vastus muscles were removed and immunostained for His48 (neutrophil)- and ED1 (macrophage)-positive cells. The postexercise increase in leukocyte infiltration was completely (p < 0.05) attenuated with estrogen supplementation alone in both muscle types, relative to sham. Progesterone treatment alone also resulted in a smaller (20%–30%) but significant (p < 0.05) attenuation of postexercise muscle leukocyte infiltration. The combination of estrogen and progesterone treatment did not significantly alter the attenuation seen with estrogen supplementation alone. Hence, progesterone can independently attenuate postexercise muscle leukocyte infiltration, albeit to a lesser degree than estrogen, and it will not negate or accentuate the effect of estrogen.
Adaptive stretch-shortening contractions: diminished regenerative capacity with aging
Authors: Baker Brent A. , Hollander Melinda S. , Mercer Robert R. , Kashon Michael L. , Cutlip Robert G.
Published: December 2008

This study determined the age-related changes in acute events responsible for initiating skeletal muscle remodeling and (or) regeneration in the tibialis anterior muscle following a bout of stretch-shortening contractions (SSCs). Changes in muscle performance and morphology were quantified in young and old rats, following an acute exposure to adaptive SSCs at 6, 24, 48, 72, and 120 h postexposure (n = 6 for each age at each recovery period). Following SSC exposure, all performance measures were decreased in old rats throughout the 120 h acute phase. Estimates of edema were increased in the old vs. young exposed muscle at 120 h recovery. Both young and old rats displayed an increase in developmental myosin heavy chain (MHCdev+) labeling in the exposed muscle, indicating muscle regeneration. However, old rats displayed diminished MHCdev+ labeling, compared with young rats, suggesting limited remodeling and (or) regenerative capacity. Based on these data, diminished local muscle remodeling and (or) regeneration with aging may limit skeletal muscle adaptation following mechanical loading.
Improved estimation of energy expenditure by artificial neural network modeling
Authors: Hay Dean Charles , Wakayama Akinobu , Sakamura Ken , Fukashiro Senshi
Published: December 2008

Estimation of energy expenditure in daily living conditions can be a tool for clinical assessment of health status, as well as a self-measure of lifestyle and general activity levels. Criterion measures are either prohibitively expensive or restricted to laboratory settings. Portable devices (heart rate monitors, pedometers) have gained recent popularity, but accuracy of the prediction equations remains questionable. This study applied an artificial neural network modeling approach to the problem of estimating energy expenditure with different dynamic inputs (accelerometry, heart rate above resting (HRar), and electromyography (EMG)). Nine feed-forward back-propagation models were trained, with the goal of minimizing the mean squared error (MSE) of the training datasets. Model 1 (accelerometry only) and model 2 (HRar only) performed poorly and had significantly greater MSE than all other models (p < 0.001). Model 3 (combined accelerometry and HRar) had overall performance similar to EMG models. Validation of all models was performed by simulating untrained datasets. MSE of all models increased when tested with validation data. While models 1 and 2 again performed poorly, model 3 MSE was lower than all but 2 EMG models. Squared correlation coefficients of measured and predicted energy expenditure for models 3 to 9 ranged from 0.745 to 0.817. Analysis of mean error within specific movement categories indicates that EMG models may be better at predicting higher-intensity energy expenditure, but combined accelerometry and HRar provides an economical solution, with sufficient accuracy.
Effect of caffeine on the neuromuscular system — potential as an ergogenic aid
Authors: Tarnopolsky Mark A.
Published: December 2008

The ergogenic effect of caffeine on endurance exercise performance is multifactorial; however, there is evidence for an effect on both the central nervous system and the excitation–contraction coupling of skeletal muscle. The increase in exercise performance seen following intracerebroventrical caffeine injection in rats provides strong evidence for a central ergogenic effect. The central ergogenic effect is not likely related to the ability of caffeine to promote wakefulness, but could be due to an increase in the pain and effort perception threshold. There is no evidence that caffeine alters peripheral nerve conduction velocity or neuromuscular transmission, and 1 study showed that motor unit synchronization was not altered by caffeine. Studies have also shown that caffeine can have a direct effect on skeletal muscle that could be ergogenic. For example, patients with high cervical spinal cord lesions showed improvements in stimulated contractile force during cycling, in spite of the fact that they have no peripheral pain input and no sympathetic nervous system response. Two studies have found a potentiation of force production during submaximal stimulation intensities, and 1 found that the M-wave amplitude was not altered by caffeine. Together, these studies suggest that caffeine can enhance contractile force during submaximal contractions by potentiating calcium release from the ryanodine receptor, not by altering sarcoplasmic excitability. Furthermore, the potentiation of force during submaximal electrical stimulation is identical in habitual and nonhabitual caffeine consumers. In summary, the ergogenic effects of caffeine during endurance activity are mediated partly by enhanced contractile force and partly by a reduction in perceived exertion, possibly though a blunting of effort and (or) pain.
Consumption of dietary caffeine and coffee in physically active populations: physiological interactions
Authors: Tunnicliffe Jasmine M. , Erdman Kelly Anne , Reimer Raylene A. , Lun Victor , Shearer Jane
Published: December 2008

Caffeine is a proven ergogenic aid, increasing athletic performance, endurance, and mental chronometry at doses as low as 1–3 mg·kg–1. As coffee is a readily available and commonly ingested form of caffeine, the two are often equated. However, coffee also contains hundreds of other biologically active compounds, many of which are metabolically distinct from caffeine. The purpose of this review was to examine the prevalence of coffee and (or) caffeine consumption among elite Canadian athletes, and to delineate the effects of coffee and caffeine on physical activity, weight maintenance, performance, and metabolism. A total of 270 self-reported 3-day food records were examined for caffeine intake from athletes registered with Canadian Sport Centres in 2005 and 2006. Athletes ranged in age from 16–45 years, and competed in 38 different sports. Results showed that 30% of athletes ingested >1 mg·kg–1·day–1from a variety of sources. Average daily intake was 0.85 ± 13 mg·kg–1. Caffeine intake was not correlated with any 1 sport; the 10 highest caffeine users were athletes from 9 different sports, including skill, endurance, and power sports. No differences were noted for average caffeine ingestion between summer and winter sports. High caffeine intakes corresponded to coffee ingestion, with the 25 highest individual intakes (193–895 mg·day–1) from coffee drinkers. In summary, it can be concluded that the majority of high-level Canadian athletes consume dietary caffeine primarily in the form of coffee. However, levels consumed are insufficient to elicit performance enhancement. Potential detrimental effects of caffeine consumption on exercise performance include gastric upset, withdrawal, sleep disturbance, and interactions with other dietary supplements.
Does caffeine alter muscle carbohydrate and fat metabolism during exercise?
Authors: Graham Terry E. , Battram Danielle S. , Dela Flemming , El-Sohemy Ahmed , Thong Farah S.L.
Published: December 2008

Caffeine, an adenosine receptor antagonist, has been studied for decades as a putative ergogenic aid. In the past 2 decades, the information has overwhelmingly demonstrated that it indeed is a powerful ergogenic aid, and frequently theories have been proposed that this is due to alterations in fat and carbohydrate metabolism. While caffeine certainly mobilizes fatty acids from adipose tissue, rarely have measures of the respiratory exchange ratio indicated an increase in fat oxidation. However, this is a difficult measure to perform accurately during exercise, and small changes could be physiologically important. The few studies examining human muscle metabolism directly have also supported the fact that there is no change in fat or carbohydrate metabolism, but these usually have had a small sample size. We combined the data from muscle biopsy analyses of several similar studies to generate a sample size of 16–44, depending on the measure. We examined muscle glycogen, citrate, acetyl-CoA, glucose-6-phosphate, and cyclic adenosine monophosphate (cAMP) in resting samples and in those obtained after 10–15 min of exercise at 70%–85% maximal oxygen consumption. Exercise decreased (p < 0.05) glycogen and increased (p < 0.05) citrate, acetyl-CoA, and glucose-6-phosphate. The only effects of caffeine were to increase (p < 0.05) citrate in resting muscle and cAMP in exercise. There is very little evidence to support the hypothesis that caffeine has ergogenic effects as a result of enhanced fat oxidation. Individuals may, however, respond differently to the effects of caffeine, and there is growing evidence that this could be explained by common genetic variations.
Performance of Pakistani volcanic ashes in mortars and concrete
Authors: Naseer Amjad , Jabbar Abdul , Khan Akhtar Naeem , Ali Qaisar , Hussain Zakir , Mirza Jahangir
Published: December 2008

Two Pakistani volcanic ashes, VA1 (as is and calcined) and VA2 (as is), were incorporated into mortar cubes, concrete cylinders, and concrete beams as a partial substitute for ordinary Portland cement (OPC), and were studied in detail. The X-ray diffraction patterns showed that both ashes possessed crystalline as well as amorphous phases. The pozzolanic activity index (PAI) of VA1 at 7 d was below 75%, whereas it was 80% at 28 d. The pozzolonic activity indices in OPC mortars containing VA2 were much higher than those for VA1, both at 7 and 28 d. In mortar cubes and concrete cylinders, approximately the same compressive strengths were observed in samples containing 100% cement as in those incorporating a 10% replacement of cement by either VA1 or VA2. Mortar cubes soaked in 5% sodium sulphate solution demonstrated consistently improved resistances to sulphate attack as ash content increased in the mortar. Similar results were also observed in water absorption tests. Modulus of rupture of all concrete beams decreased as the levels of VA1 and VA2 increased from 10% of OPC content to 40%. Rupture moduli were higher for VA1 than for VA2 at all cement replacement levels.
Recombinant mouse SPARC promotes parietal endoderm differentiation and cardiomyogenesis in embryoid bodies
Authors: Hrabchak Christopher , Ringuette Maurice , Woodhouse Kimberly
Published: December 2008

In the absence of leukemia inhibitory factor, murine embryonic stem cells cultured in vitro spontaneously aggregate to from three-dimensional embryoid bodies that differentiate to produce hematopoietic, endothelial, muscle, and neuronal cell lineages in a manner recapitulating the events of early embryogenesis. Cardiomyogenesis in embryoid bodies was recently demonstrated to be promoted by PYS-2-derived native SPARC (secreted protein, acidic and rich in cysteine), whose expression is upregulated in parietal endoderm at the onset of the epithelial to mesenchymal transition. Here, we confirm the stimulatory effects of mouse SPARC on cardiomyogenesis using a recombinant baculovirus-produced protein (rmSPARC). Embryoid bodies cultured in the presence of glycosylated rmSPARC, or an unglycosylated peptide spanning the C-terminal EF-hand domain, developed greater numbers of beating cardiomyocytes than did time-matched controls, with enhanced expression of cardiac marker genes including Nkx2.5, Troponin, BMP-2, and MHCα. Histochemical analysis revealed an expansion of the peripheral endoderm, with thicker layers of extracellular matrix (ECM) material observed atop underlying cells. Embryoid bodies treated with SPARC also displayed increased adherence to polystyrene culture dishes, with enhanced expression of ECM mRNAs including collagen IVα3, collagen IVα5, and laminin α1. These results indicate that, in addition to the promotion of cardiomyogenesis, SPARC may also help regulate the molecular composition and organization of ECM secreted by the mesenchymal parietal endoderm.
Cast-in-place bored piles on soft rock under artesian pressures
Authors: Sharma Hari D. , Sengupta S. , Harron Glen
Published: December 2008

This paper outlines the geotechnical investigations and axial compression, pullout, and lateral pile load tests that were carried out at a site where cast-in-place bored concrete piles were installed. These piles were designed to bear on top of soft weathered rock surface that was under artesian pressures. Pile load test results have been compared with theoretically calculated pile capacities. It has been found that in areas of high artesian pressures in bedrock axial compressive pile load capacities theoretically estimated by conventional methods were significantly higher than the values obtained from load tests. Recommendations have been made that representative exposed bedrock samples be tested to determine their undrained strength, and these values be used for estimating theoretical pile capacities. Construction problems encountered during pile installation, such as locating the top of weathered bedrock without penetrating through water-bearing layers that were under artesian pressures, are presented briefly and a solution provided to install belled piles on top of bedrock is discussed. Key words: bored concrete piles, construction problems, load tests, soft weathered rock under artesian pressures, ultimate pile load capacities.
A chart for estimating the average vertical stress increase in an elastic foundation below a uniformly loaded rectangular area
Authors: Griffiths D. V.
Published: December 2008

In spite of the considerable assumptions involved, stress distribution charts based on elastic theory are still used by engineers to estimate stresses induced in soil masses by surface loading. Although there are limited data comparing calculated and measured stress increments, vertical stress components have been predicted quite reliably by this method. The chart presented here enables the average vertical stress increment beneath a corner of a uniformly loaded rectangular area to be estimated. The results are based on numerical integration of existing solutions for the rectangle problem, and should reduce the need for sublayers when calculating consolidation settlements. Key words: stress distribution, elasticity, design graph, rectangular footing, consolidation.