bluuebunny/crossref_metadata_2025 huggingface dataset:
Myocyte differentiation generates nuclear invaginations traversed by myofibrils associating with sarcomeric protein mRNAs
Authors: Abe Tomoyuki , Takano Kazunori , Suzuki Akiko , Shimada Yutaka , Inagaki Masaki , Sato Naruki , Obinata Takashi , Endo Takeshi
Published: December 2004

Certain types of cell both in vivo and in vitro contain invaginated or convoluted nuclei. However, the mechanisms and functional significance of the deformation of the nuclear shape remain enigmatic. Recent studies have suggested that three types of cytoskeleton, microfilaments, microtubules and intermediate filaments, are involved in the formation of nuclear invaginations, depending upon cell type or conditions. Here, we show that undifferentiated mouse C2C12 skeletal muscle myoblasts had smoothsurfaced spherical or ellipsoidal nuclei, whereas prominent nuclear grooves and invaginations were formed in multinucleated myotubes during terminal differentiation. Conversion of mouse fibroblasts to myocytes by the transfection of MyoD also resulted in the formation of nuclear invaginations after differentiation. C2C12 cells prevented from differentiation did not have nuclear invaginations, but biochemically differentiated cells without cell fusion exhibited nuclear invaginations. Thus, biochemical differentiation is sufficient for the nuclear deformation. Although vimentin markedly decreased both in the biochemically and in the terminally differentiated cells, exogenous expression of vimentin in myotubes did not rescue nuclei from the deformation. On the other hand, non-striated premyofibrils consisting of sarcomeric actinmyosin filament bundles and cross-striated myofibrils traversed the grooves and invaginations. Time-lapse microscopy showed that the preformed myofibrillar structures cut horizontally into the nuclei. Prevention of myofibril formation retarded the generation of nuclear invaginations. These results indicate that the myofibrillar structures are, at least in part, responsible for the formation of nuclear grooves and invaginations in these myocytes. mRNA of sarcomeric proteins including myosin heavy chain and α-actin were frequently associated with the myofibrillar structures running along the nuclear grooves and invaginations. Consequently, the grooves and invaginations might function in efficient sarcomeric protein mRNA transport from the nucleus along the traversing myofibrillar structures for active myofibril formation.
Compartmentalisation of the sperm plasma membrane: a FRAP, FLIP and SPFI analysis of putative diffusion barriers on the sperm head
Authors: James Peter S. , Hennessy Conor , Berge Torunn , Jones Roy
Published: December 2004

Spermatozoa are highly polarised cells with a compartmentalised distribution of lipids and proteins in their plasma membrane. It is not known how these compartments are stably maintained in what is essentially a fluid environment. In this investigation we have examined the hypothesis that intramembranous diffusion barriers selectively retain some components within compartments, while allowing free passage of others. A fluorescence loss in photobleaching analysis of the behaviour of the lipid reporter probe 1,1′-dihexadecyl-3,3,3′3′-tetramethyindocarbocyanine (DiIC16) on the head of boar spermatozoa revealed that it was freely diffusing between all three compartments (anterior acrosome, equatorial segment and postacrosome). Spermatozoa also contained rapidly diffusing particles of DiIC16 over the anterior acrosome and equatorial segment. These particles, ∼200 nm in diameter, were tracked in real time and their trajectories analysed by mean square displacement. Particle diffusion was essentially random over the anterior acrosome and equatorial segment but showed a periodicity in jump sizes and diffusion coefficients suggestive of microheterogeneities. Particles did not exchange between the equatorial segment and postacrosome, indicating a barrier at the junction between these two compartments. No barrier was detected between the equatorial segment and anterior acrosome. A model is proposed in which a molecular `filter' is present at the equatorial segment-postacrosomal boundary that allows free passage of single molecules but not molecular complexes. Passage of heterogeneous complexes, such as lipid rafts, requires disassembly and reassembly on either side of the filter.
In vivo analysis of 3-phosphoinositide dynamics duringDictyosteliumphagocytosis and chemotaxis
Authors: Dormann Dirk , Weijer Gerti , Dowler Simon , Weijer Cornelis J.
Published: December 2004

Phagocytosis and chemotaxis are receptor-mediated processes that require extensive rearrangements of the actin cytoskeleton, and are controlled by lipid second messengers such as phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] and phosphatidylinositol 3,4-bisphosphate [PtdIns(3,4)P2]. We used a panel of pleckstrin homology (PH) domains with distinct binding specificities for PtdIns(3,4,5)P3 and PtdIns(3,4)P2 to study the spatiotemporal dynamics of these phosphoinositides in vivo. During phagocytosis and macropinocytosis PtdIns(3,4,5)P3 levels transiently increased at sites of engulfment, followed by a rapid PtdIns(3,4)P2 production round the phagosome/macropinosome upon its internalisation, suggesting that PtdIns(3,4,5)P3 is degraded to PtdIns(3,4)P2. PTEN null mutants, which are defective in phagocytosis, showed normal rates of PtdIns(3,4,5)P3degradation, but unexpectedly an accelerated PtdIns(3,4)P2 degradation. During chemotaxis to cAMP only PtdIns(3,4,5)P3 was formed in the plasma membrane, and no PtdIns(3,4)P2 was detectable, showing that all PtdIns(3,4,5)P3 was degraded by PTEN to PtdIns(4,5)P2. Furthermore, we showed that different PtdIns(3,4,5)P3 binding PH domains gave distinct spatial and temporal readouts of the same underlying PtdIns(3,4,5)P3 signal, enabling distinct biological responses to one signal.
Electronic control units for automotive electrical power systems: Communication and networks
Authors: Shrinath A , Emadi A
Published: December 2004

The last decade has seen a resurgence of advanced technologies being implemented in automobiles. Functions that were considered highly complex and difficult to be implemented are not only being provided but various other facilities are also being built on those very functions. Everything from engine control to multimedia and infotainment services are implemented in today's automobiles. This has been due largely to the strides made by the electronics as well as the communications industry. The emergence of the concept of providing the customer with all possible services has led to an explosion of implementation of high-end electronics, each providing a facility of its own. When so many devices are being embedded in a car, there also has to be a mechanism that should regulate the way in which data transfer takes place. It is the objective of this paper to provide an insight into most of the communication protocols that are being used, as well as technologies that are under development in the automobile industry of today. Various protocols and their modus operandi are explained, with schematics completing the picture.
Modelling of oxygen storage in automotive catalysts
Authors: Khossusi T , McCullough G , Douglas R
Published: December 2004

The designers of catalytic converters have found that the use of cerium oxide in the washcoat formulation, to store and release oxygen, gives higher conversion efficiencies in three-way catalysts. It has also been shown that oscillating the air-fuel ratio around λ = 1, which effectively oscillates the oxygen concentration, is a useful method of using this oxygen storage capability. This paper describes a detailed mathematical model for oxygen storage, which forms an important part of a complete kinetic model of a three-way automotive catalyst. This model consists of two interdependent submodels: one for the oxidation process and a second for the reduction process. In this study, O2 and NO were used as oxidizing agents and CO, C3H6 and C3H8 were used as reducing agents. The structure and equations of the model are presented and discussed in detail. Some validation work has also been carried out on a purpose-built miniature catalyst test rig. The purpose of this work was to provide the important kinetic factors for the reaction equations. The result of this analysis is included and compared with other published data.
An experimental study of low-frequency motion in cars
Authors: Griffin M J , Newman M M
Published: December 2004

Low-frequency acceleration can cause discomfort, instability and motion sickness, but there is little published information on this type of motion in cars. Accelerations in the fore-and-aft, lateral and vertical directions were measured continuously while driving around a fixed suburban route for 30 min. In separate studies, the variations in accelerations with the same driver driving the same car, the same driver driving different cars, and different drivers driving the same car were determined. The spectra of fore-and-aft and lateral accelerations were similar over the frequency range 0.1-0.5 Hz and, in consequence, motion sickness dose values (MSDVs) were similar in these axes when calculated using the frequency weighting in current standards. At frequencies less than 0.1 Hz, fore-and-aft acceleration was greater than lateral acceleration. The MSDVs for vertical acceleration were appreciably less than those for fore-and-aft and lateral acceleration. Acceleration in the vertical direction was predominantly influenced by vehicle suspension dynamics, with peaks between 1.0 and 2.0 Hz, and the differences between vehicles were greater than the differences between drivers. The fore-and-aft and lateral acceleration (as reflected in the MSDVs) showed differences between drivers that were greater than the differences between vehicles. Although such low-frequency fore-and-aft and lateral acceleration in cars is dependent on the behaviour of the drivers, some human responses to these motions may be modified by vehicle design.
Effect of the setting angle of a low-solidity vaned diffuser on the performance of a centrifugal compressor stage
Authors: Reddy T Ch Siva , Murty G V Ramana , Mukkavilli P , Reddy D N
Published: December 2004

The present investigation is undertaken to study the performance of an existing stage of an industrial centrifugal compressor with a vaneless diffuser and is aimed at improving the efficiency of the compressor stage through the use of a low-solidity (LSD) vaned diffuser. The experiments were conducted at a tip Mach number of 0.35. The LSD vane is formed from a standard aerofoil profile with marginal modification in the trailing edge region. The study was conducted at a solidity ratio of 0.81, which is considered as the optimum for the chosen stage. The overall stage performance for different diffuser vane setting angles was evaluated in terms of flow coefficient, head coefficient, polytropic efficiency and static pressure recovery coefficient. The performance parameters are normalized with respect to those of the vaneless diffuser at design flow. Improvement in performance as well as static pressure recovery was observed with LSD vanes as compared with a vaneless diffuser configuration. Variation in blade loading was studied from measurements of static pressure on the pressure and suction surfaces of LSD vanes at different vane setting angles. It was observed that the vane setting angle has a significant effect on stage performance and also on the blade loading.
Observation of Gas-to-Particle Conversion at Low Concentration of SO2 by Using a Flow-type Reactor
Authors: Kobara Hitomi , Yamauchi Hideaki , Takeuchi Koji , Ibusuki Takashi
Published: December 2004

Particle generation by SO2 gas-to-particle conversion in a flow-type reactor was examined. The reactor can minimize losses of reactants and products due to adsorption onto the wall surface, and a material balance between consumed SO2 and sulfate in generated particles was in very good agreement as compared with previous studies.
Asymmetric Hydrogenation of the C–C Double Bond of Enones with the Reductases from Nicotiana tabacum
Authors: Hirata Toshifumi , Shimoda Kei , Gondai Takayuki
Published: December 2004

Three enone reductases, p44, p74, and p90, from the cultured cells of Nicotiana tabacum catalyzed the asymmetric hydrogenation of the C–C double bond of enones. Reduction of 2-alkyl-2-cyclohexen-1-ones with the p44 reductase gave highly optically active (R)-2-alkylcyclohexanones, whereas reaction with the p90 reductase gave (S)-2-alkylcyclohexanones. On the other hand, reduction of 2-alkylidenecyclohexanones with the p74 reductase gave (S)-2-alkylcyclohexanones.
Preparation of Super-Water-Repellent Alumina Coating Film with High Transparency on Poly(ethylene terephthalate) by the Sol–Gel Method
Authors: Tadanaga Kiyoharu , Kitamuro Kaori , Morinaga Junichi , Kotani Yoshinori , Matsuda Atsunori , Minami Tsutomu
Published: December 2004

Al2O3 gel films were prepared on poly(ethylene terephthalate) substrates from Al(O–sec-C4H9)3 chemically modified with ethyl acetoacetate. A small roughness of about 20–50 nm was found to form on the Al2O3 gel films dried at room temperature and then immersed in hot water at 60 °C. When hydrolyzed fluoroalkyltrimethoxysilane was coated on the Al2O3 films, transparent thin films with contact angle for water to be more than 150° were obtained.
Microbial Growth Regulation Using Photoresponsive Siderophore
Authors: Masuda Takeshi , Azuma Masayuki , Ooshima Hiroshi , Tamagaki Seizo , Nagasaki Takeshi
Published: December 2004

A new trihydroxamate siderophore containing a reversibly cis / trans-controllable azobenzene framework has been examined for biological activity with Aureobacterium flavescens. The cis-Fe(III)-complex in monomeric form shows a remarkable activity comparable to ferrioxamine B, a natural siderophore, but no activity is observed with the trans-Fe(III)-complex in dimeric form.
Hydrothermal Synthesis of Cubic Mesostructured Vanadium–Phosphorus Oxide
Authors: Hatayama Hiroshi , Misono Makoto , Taguchi Akira , Mizuno Noritaka
Published: December 2004

Previously unknown cubic mesostructured vanadium–phosphorus oxide was synthesized by using V metal not only as a V source but also as a reducing agent for V2O5.
Grafting of Polymers onto Carbon Fiber Surface by Ligand Exchange Reaction of Poly(vinylferrocene-co-methyl methacrylate) with Polycondensed Aromatic Ring of the Surface
Authors: Tsubokawa Norio , Abe Nobuyuki , Seida Yohko , Fujiki Kazuhiro
Published: December 2004

The grafting reaction of poly(vinylferrocene-co-methyl methacrylate) onto carbon fiber (CF) surface was successfully achieved by ligand exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of CF in the presence of AlCl3 and aluminum powder. The percentage of grafting onto CF surface reached to 46.1%.
Efficient Dihydroxylation of Naphthalene on Photoirradiated Rutile TiO2 Powder in Solution Containing Hydrogen Peroxide
Authors: Jia Jianguang , Ohno Teruhisa , Matsumura Michio
Published: December 2004

We report on enhanced dihydroxylation of naphthalene on photoirradiated TiO2 particles by addition of H2O2 to the reaction solution. The rate was enhanced by 6–40 times by the addition of H2O2, and the quantum yield reached as high as 76% for rutile TiO2 powders. On the other hand, no such enhancement was observed for anatase TiO2 powders.
Cobalt Rhenium Binary Catalyst for Ammonia Synthesis
Authors: Kojima Ryoichi , Aika Ken-ichi
Published: December 2004

Co–Re catalyst (Co : Re = 1 : 4) prepared by reduction of cobalt nitrate hydrate and ammonium perrenate mixture with ammonia at 973 K was very active for ammonia synthesis (2.4 mmol h−1g−1) at 623 K under 3.1 Mpa (N2 + 3H2, 60 mL min−1) in spite of extremely low surface area (< 0.5 m2 g−1).
Precise Synthesis and Properties of Poly(isocyanide)s Bearing Porphyrins as a Pendant Group
Authors: Takei Fumie , Onitsuka Kiyotaka , Kobayashi Nagao , Takahashi Shigetoshi
Published: December 2004

Aryl isocyanide bearing porphyrin has been prepared and polymerized by Pd–Pt µ-ethynediyl complex as an initiator to produce novel polymers. The UV–VIS absorption spectra suggest that porphyrin groups in their side chains are regularly arranged by the helical main chain of poly(isocyanide)s.
Lithium-Selective Coloration of Spirobenzopyran Derivative Incorporating Monoaza-12-Crown-4 in Micellar Solution
Authors: Sakamoto Hidefumi , Tanaka Mutsuo , Kimura Keiichi
Published: December 2004

A spirobenzopyran derivative bearing a monoaza-12-crown-4 moiety and an octadecyl group as a lipophilic chain was synthesized and was used as a chromogenic reagent for alkali metal ion in micellar solutions. The crowned spirobenzopyran derivative exhibited highly Li+-selective spectral changes under high pH conditions.
High Pressure Effects on Fluorescence-Quenching of Coumarin 343 Adsorbed on TiO2 Nanocrystallites in Methanol and in N,N-Dimethylformamide
Authors: Matsumoto Masamitsu , Murakoshi Kei , Wada Yuji , Yanagida Shozo
Published: December 2004

The effect of high pressures up to 400 Mpa on the emission quenching of Coumarin 343 (C343) adsorbed on TiO2 nanocrystallites in methanol (MeOH) and N,N-dimethylformamide (DMF) solution was investigated. In MeOH, the quenching efficiency decreased as the pressure increased. This decrease was explained by the decrease of the adsorption strength of C343 onto TiO2 nanocrystallites. On the contrary, the efficiency in DMF increased with increase of pressure in spite of decrease of adsorption strength of C343 onto TiO2 under the high pressure condition, indicating enhancement in the electron transfer efficiency. The results imply that the high pressure technique can control the efficiency of photo-induced electron transfer systems.
Ethidium Bromide Binding Sites in DNA Gel
Authors: Yonekura Nobuaki , Mutoh Masatoshi , Miyagi Yusei , Takushi Eisei
Published: December 2004

The analysis of fluorescence decays of ethidium bromide (EtBr) in DNA gels has revealed two EtBr binding sites: a DNA double helix site and a cross-linking site. EtBr preferentially binds to the latter site.
C60 Self-Assembled Monolayer Using Diamine as a Prelayer
Authors: Kim Kyuwon , Song Hyunjoon , Park Joon T , Kwak Juhyoun
Published: December 2004

Diamines (NH2(CH2)nNH2; n = 4, 6, 12) have been employed as a prelayer for immobilizing C60 onto ITO electrode. The C60/diamine/ITO system reveals good electrochemical responses for surface-confined C60.
Molecular imaging using hyperpolarized 13C
Authors: Golman K , Olsson L E , Axelsson O , Månsson S , Karlsson M , Petersson J S
Published: December 2004

MRI provides unsurpassed soft tissue contrast, but the inherent low sensitivity of this modality has limited the clinical use to imaging of water protons. With hyperpolarization techniques, the signal from a given number of nuclear spins can be raised more than 100 000 times. The strong signal enhancement enables imaging of nuclei other than protons, e.g.  13C and 15N, and their molecular distribution in vivo can be visualized in a clinically relevant time window. This article reviews different hyperpolarization techniques and some of the many application areas. As an example, experiments are presented where hyperpolarized 13C nuclei have been injected into rabbits, followed by rapid 13C MRI with high spatial resolution (scan time <1 s and 1.0 mm in-plane resolution). The high degree of polarization thus enabled mapping of the molecular distribution within various organs, a few seconds after injection. The hyperpolarized 13C MRI technique allows a selective identification of the molecules that give rise to the MR signal, offering direct molecular imaging.
A New Method for Evaluating the Risk of DEF
Authors: Tagnit-Hamou A , Petrov N
Published: December 2004

A new method involving a slight acceleration of curing is proposed to evaluate the sensitivity of a particular cement or particular mortars to DEF and consequent expansion. It can be used to determine the maximum concrete temperature below which the risk of DEF is minimal and acceptable. After a heat curing, the specimens were kept in lime-saturated water. On the seventh day, they were submitted to six daily thermal cycles (+50 to +10°C). Expansion is greater when thermal cycles are applied compared to control specimens. Therefore, the absence of expansion of some mortars submitted to thermal cycles enables us to accept the mix, even if the curing temperature is 90°C. This method has been applied successfully in mortar specimens. It is presently being applied on concrete specimens.
Influence of Specimen Geometry, Orientation of Casting Plane, and Mode of Concrete Consolidation on Expansion Due to ASR
Authors: Smaoui N , Bérubé MA , Fournier B , Bissonnette B
Published: December 2004

Concrete specimens of different sizes and shapes were made with various reactive aggregates and stored under conditions favorable to the development of alkali-silica reactivity (ASR), with their expansion measured with time along the three directions. They have been cast vertically (cylinders and prisms) or horizontally (prisms and larger blocks), using a vibrating table, a vibrating needle, or rodding. The expansion due to ASR was always greater in the direction perpendicular to the casting plane. The higher the number of flat and elongated particles in the reactive aggregate, the higher the coefficient of anisotropy, defined as the ratio between the expansions perpendicular and parallel to the casting plane. This coefficient was constant through the course of the expansion. It was generally higher for the cylinders than for the prisms, and still less for larger blocks. Consolidation by rodding induced anisotropy coefficients distinctly smaller than consolidation using a vibrating table, while a vibrating needle induced intermediate values; however, all methods gave constant volumetric expansion at least up to an important expansion level. For prisms cast horizontally and measured axially in accordance with the concrete test CSA A23.2-14A or ASTM C 1293, consolidation using rodding induced long-term (axial) expansions greater by 71% compared with consolidation using a vibrating table. In order to reduce the experimental variability of the test, only one method of consolidation should be allowed. When evaluating field concrete affected by ASR, it appears important to consider the orientation with respect to the casting plane of the core samples subjected to mechanical or residual expansion tests.
Effect of Non-Uniform Straining in Concrete Compressive Strength Tests
Authors: Luker I , Tabsh SW
Published: December 2004

If a concrete specimen is tested to failure in compression and the machine allows the longitudinal strain in the specimen to be non-uniform over the cross-section of the specimen at its maximum load, then that load is lower than it would be if the strains were uniform. The results of an experimental study on the magnitude of the effect of non-uniform straining on apparent concrete strength are presented, showing how it varies for low, medium, and high strength concrete. Simple theoretical modeling is shown to reproduce the measured results well. Suggestions are also included for the application of the information presented.
Resistance to Freezing and Thawing Cycles and Scaling Resistance of Very High Early Strength Concrete
Authors: Kurtz MA , Constantiner D
Published: December 2004

A very high early strength portland cement-based concrete (VHES) is used to prevent long closures of highway lanes by completing any necessary repairs overnight. This technology has been embraced by several DOT agencies, including those in areas where the concrete will be subjected to freezing and thawing cycles. Flexural strength of VHES concrete is the critical parameter to permit traffic flow without damage to the concrete. It is possible to produce air-entrained rapid repair concrete, but this places higher requirements on the mixture proportions to overcome strength reduction caused by the presence of air. This article presents data showing that it is possible to attain the necessary strength and achieve adequate resistance to freezing and thawing cycles. The evidence presented includes accelerated testing using ASTM C 666, Procedure A, and scaling resistance using ASTM C 672. Additional evidence is presented showing that VHES concrete of low w/c can be durable with larger than acceptable spacing factor levels or without air entrainment.
New Results on Early-Age Cracking Risk of Special Concrete
Authors: Schiessl P , Beckhaus K , Schachinger I , Rucker P
Published: December 2004

The Center of Building Materials (cbm) at the Technische Universitaet Muenchen has many years of experience in the early-age cracking risk of concrete. So far most of the investigations have been focused onmass concrete with regard to its semi-adiabatic thermal behavior—the development of uniaxial restraint stress during hardening has been determined in the cracking frame, simulating the centre of an approx. 50 cm-thick concrete. New results on the early-age cracking risk of special concretes with regard to their specific conditions or composition that is different to that of ordinary mass concrete will be shown in this paper. These special concretes are self-compacting concrete, pavement concrete, high-strength concrete and in particular ultrahigh-performance concrete with a compressive strength of up to 200 MPa at an age of 28 days. Furthermore, a test-based calculation method using the finite element method (FEM) was developed to predict, for example, the thermal restraint stress in concrete structures under various weather and curing conditions. The restraint stress distribution at any location in the concrete can be calculated realistically by applying appropriate rheological models for which “true values” of particular early-age concrete properties are required, which have to be determined experimentally.
Liquid Limit and Specific Surface of Clay Particles
Authors: Dolinar B , Trauner L
Published: December 2004

In this paper a new method for determining the liquid limit of nonexpanding soils is presented. The liquid limit value primarily depends on the type and quantity of clay minerals in soils. This relationship, however, has never been presented in general analytical form that would enable a consistent determination of the influence of mineralogical properties of different soils on the liquid limit. The findings described in the article define those mineralogical properties of soils, which determine the quantity of water at the liquid limit. It was found that the water content at the liquid limit depends on the size and the quantity of clay grains in soils that contain only nonexpanding minerals. In case of expanding minerals in soils, the size and the quantity of clays determine only the quantity of intergrain water, while the total water content depends on the quantity of interlayer water also.
Evaluation of Various Downhole Data Reduction Methods for Obtaining Reliable VS Profiles
Authors: Kim D-S , Bang E-S , Kim W-C
Published: December 2004

The downhole method has been widely used to measure in situ shear wave velocity profiles for the seismic response analysis of geotechnical sites. To analyze the downhole data, the direct and interval methods are mostly used in practice. In this study, the modified interval method based on a straight ray path and the inversion method based on Snell's Law ray path were introduced to improve the quality of the wave velocity profiles evaluated by the downhole seismic method. Various synthesized wave velocity profile models were developed to perform the parametric study and the arrival times were determined by a forward modeling scheme based on Snell's Law. By comparing the velocity profiles obtained by four different data reduction methods with actual velocity profiles, the accuracy and limitation of various data reduction methods were assessed. The direct method was difficult for evaluating the detailed velocity profiles, and the interval method was found to provide severe errors, particularly when a stiff layer is located beneath the soft layer. The modified interval method provides reliable results, except when a strong soft-to-stiff contrast exists. Snell's Law ray path method provides the most reliable velocity profiles. Finally, in situ downhole seismic tests were performed at three sites, and the importance of considering the ray path in the data reduction was emphasized by comparing the reduced shear wave velocity profiles with crosshole and standard penetration test results.
Determination of the Hydraulic Conductivity Function of a Highly Compressible Material Based on Tests with Saturated Samples
Authors: Parent S-É , Cabral A , Avanzi ED , Zornberg JG
Published: December 2004

An alternative procedure to determine the hydranlic conductivity function (k-function) based on relationships between saturated hydraulic conductivity and void ratio and between air-entry value and void ratio is proposed. The procedure was applied to determine the k-function of deinking by-products, a highly compressible industrial by-product that is used as alternative material in geoenvironmental applications. The validity of the procedure is verified by comparing the k-function of a compressible soil obtained based on the proposed procedure (using published experimental data) with experimentally determined unsaturated hydraulic conductivities for the same soil.
Testing the Hydromechanical Behavior of a Compacted Swelling Soil
Authors: Cuisinier O , Masrouri F
Published: December 2004

The paper presents a study of the hydromechanical behavior of a compacted swelling soil in a range of suctions comprised between 0 and around 300 MPa. To perform this study, two kinds of suction controlled oedometers were used, one using the osmotic method and the other using the salt solution method. A detailed review of the conditions for using these two methods is given in the first part of the paper. The second section provides the results of several suction controlled oedometer tests performed in this range of suction. They show that the mechanical behavior of the tested swelling material is strongly affected by the applied suction, even in the high suction range. In addition, it appeared that the samples preparation technique significantly influenced the hydromechanical behavior of the tested soil.
Shear Band Characterization of Triaxial Sand Specimens Using Computed Tomography
Authors: Batiste SN , Alshibli KA , Sture S , Lankton M
Published: December 2004

A thorough quantitative analysis of the internal density distribution and strain localization of axisymmetric triaxial sand specimens is presented. Computed tomography technique was used to acquire detailed three-dimensional images of a series of Ottawa sand specimens subjected to Conventional Triaxial Compression (CTC) conditions at very low effective stresses in microgravity and terrestrial laboratories. Analysis tools were developed to quantify the distribution of local void ratio, track the onset, propagation, thickness, and inclination angle of shear bands, and calculate the variation of void ratio within and outside shear bands. It has been found that shear bands initiate in the post-peak strength regime in CTC specimens, where a rather complex pattern of shear bands develops such that behavior is highly influenced by large-scale kinematics of the specimen. Four main deformation patterns were identified and their contribution to the overall volume change of the specimens was quantified.
Fatigue Crack Closure and Crack Growth Following an Overload
Authors: Verma BB , Pandey RK
Published: December 2004

The present investigation studies the effect of a single tensile overload cycle on fatigue crack closure and its mechanism. Attempts have also been made to study the crack growth kinetics following the overload application. It is concluded that Stage I-type of crack propagation occurs in the early stage of crack growth subsequent to overloading and the same is dominated by asperity-induced closure. A material - and loading-independent relationship has also been attempted between an overload-induced closure parameter and the overloading ratio.
Cone Resistance of Compacted Ash Fill
Authors: Trivedi A , Singh S
Published: December 2004

Coal ash is a granular byproduct of the combustion of coal in coal-fired thermal power plants. The compacted ash is frequently used as a structural fill material. Standard geotechnical investigation methods used for natural soils have revealed inconsistencies when extended to ash fills. The characterization of ash shows morphological dissimilarity with natural soils. It is observed that several groupings of in situ density and stress level lead to similar penetration resistance in coal ash. Thus, the correlations reliable for soils may have questionable interpretations of blow count or measured cone resistance in coal ash. The static cone penetration test results analyzed at various combinations of stress level and relative density indicated the need for a new scheme for interpretation of behavior of ash fills on the basis of relative dilatancy of the ash. The resistance to penetration of the standard cone was interpreted at varying depths on ash fill compacted at varying relative densities. Correlations are suggested to estimate bearing capacity and settlement characteristics of coal ash on the basis of cone penetration test results for direct geotechnical design.
Effect of Loading Schemes on Depth-Sensing Indentation Tests
Authors: Zhang J-M , Xu K-W , Lu J , Guelorget B
Published: December 2004

Constant loading rate divided by load (˙P/P) indentation tests have been conducted on high purity copper at room temperature. The results show that: 1) The loading curves can be fitted to a power-law relationship of the form P = Chn and the exponent n increases with decreasing P/P. 2) The hardness value itself, and its decreasing rate with depth, increase with increasing P/P. 3) A constant P/P can result in a constant indentation strain rate (h/h), even if indentation size effects (ISE) exist in the materials. 4) The relationship between P/P and h/h can be shown to be P/P = n.(h/h).
Modeling of Cumulative Mass Loss—Time Curves for Six Erosion and Abrasion Test Methods
Authors: Meged Y
Published: December 2004

Cumulative mass loss-time curves of six erosion and abrasion test methods are studied. These methods include: vibratory cavitation erosion, film cavitation erosion, flow cavitation erosion, cavitating liquid jet erosion, liquid impact erosion, and slurry abrasion. It has been previously well established that the cumulative erosion-time curves of vibratory cavitation erosion tests can be modeled by the Weibull cumulative distribution function. Validity of this model is further extended for the five additional erosion test methods.

The typical Weibull plot for these test methods is bimodal, consisting of two intersecting straight lines. Mode 1 of the plot represents the boundary layer, and Mode 2 represents the base material of the specimen. This type of plot is the result of a two-layered test specimen.

Data obtainable from the cumulative erosion-time curve are rather limited, since the analysis is empirical. Analysis of the Weibull cumulative distribution function plots yields much more information, and facilitates the evaluation of the test specimen's structure, test procedure, and test results.
Piezoelectric Sensors for Weigh-In-Motion Systems: An Experimental Insight into Edge Effects
Authors: Iaquinta J , Merliot E , Cottineau L-M , Desroche J-P
Published: December 2004

Experimental campaigns conducted on the theme of weigh-in-motion exhibited an unexpected scattering of the weight measurements. In spite of several attempts, no argument was found to satisfactorily explain the dispersal, in particular for the sites implementing piezoelectric sensors. After tackling this problem numerically in a previous study, the present investigation aims at understanding experimentally the behavior of such systems within the material in which they are embedded in the road. A field campaign utilizing an instrumented truck confirmed a loss of sensitivity at the ends of the sensor. This result was also corroborated by laboratory testing on a servohydraulic jack. It is shown that the location of a load over the sensor affects its response, and that only a small part of the traffic lane is saved from edge effects. The major mission of this work is to make users of weigh-in-motion systems based upon piezoelectric sensors aware of this phenomenon so that they can take actions to recognize and compensate for the potential measurement errors associated with using this type of sensor.
Enhanced Inhibitory Synaptic Transmission in the Cerebellar Molecular Layer of the GluRδ2 Knock-Out Mouse
Authors: Ohtsuki Gen , Kawaguchi Shin-ya , Mishina Masayoshi , Hirano Tomoo
Published: December 2004

A novel ionotropic glutamate receptor subunit δ2 (GluRδ2), which is specifically expressed in cerebellar Purkinje neurons (PNs), is implicated in the induction of long-term depression. Mutant mice deficient in GluRδ2 (δ2-/-) have abnormal cerebellar synaptic organization and impaired motor coordination and learning. Previousin vivoextracellular recordings inδ2-/-revealed that PN activity distinct from that in wild-type (WT) mice is attributable to enhanced climbing fiber activity. Here, we report that GABAergic synaptic transmission was enhanced in the molecular layer of the cerebellar cortex in δ2-/-. Optical recordings in cerebellar slice preparations indicated that application of bicuculline, a GABAAreceptor antagonist, increased the amplitude and area of excitation propagation more in δ2-/-than in WT. Whole-cell patch-clamp recordings from PNs demonstrated that miniature IPSC (mIPSC) amplitude were larger in δ2-/-than in WT. Also, rebound potentiation (RP), a type of long-lasting inhibitory synaptic potentiation inducible by postsynaptic depolarization of PNs in WT, was not induced in slices prepared from δ2-/-. In contrast, RP was induced in cultured PNs prepared from δ2-/-. Pharmacologic activation of climbing fibers in WTin vivoincreased mIPSC amplitudes in PNs and prevented RP induction. These results suggest that enhanced climbing fiber activity in δ2-/-potentiates IPSC amplitudes in PNs through RPin vivo, resulting in the prevention of additional RP induction.
N-Cadherin Juxtamembrane Domain Modulates Voltage-Gated Ca2+Current via RhoA GTPase and Rho-Associated Kinase
Authors: Piccoli Giuseppe , Rutishauser Urs , Brusés Juan L.
Published: December 2004

The juxtamembrane domain (JMD) of N-cadherin cytoplasmic tail is an important regulatory region of the clustering and adhesion activities of the protein. In addition, the JMD binds a diversity of proteins capable of modifying intracellular processes including cytoskeletal rearrangement mediated by Rho GTPases. These GTPases also function as regulators of voltage-activated calcium channels, which in turn modulate neuronal excitability. The present study was designed to determine whether there is a direct functional link, via Rho GTPase, between the N-cadherin JMD and these voltage-activated channels. It was found that the infusion of the soluble JMD into chick ciliary neurons causes a substantial decrease in the amplitude of the high-threshold voltage-activated (HVA) calcium current. The activation time is increased while the inactivation process is reduced, suggesting that the decreased current amplitude reflects a reduction in the number of channels available to open. This effect was reversed by inhibition of RhoA or its downstream effector, Rho-associated kinase (ROCK). Because ROCK determines the active state of myosin, these results suggest that the modulation of HVA by the JMD could be mediated by changes in the status of the actin-myosin cytoskeleton.
Selectfluor: Mechanismen und Anwendungen
Authors: Nyffeler Paul T. , Durón Sergio Gonzalez , Burkart Michael D. , Vincent Stéphane P. , Wong Chi‐Huey
Published: December 2004

Der Ersatz von Wasserstoff durch Fluor in organischen Substraten ist wegen der hohen Elektronegativität des Fluors bei fast gleich bleibendem Raumanspruch von großem Interesse in der Synthesechemie. Viele Quellen für nucleophiles Fluor zur Derivatisierung unter sauren, basischen und neutralen Bedingungen stehen zur Verfügung. Hingegen erforderte eine elektrophile Fluorierung früher den Einsatz von molekularem Fluor, was aufgrund dessen Toxizität und Explosionsneigung zu einer nur begrenzten Anwendung dieser Methode geführt hat. Der Bedarf an einem elektrophilen Fluorierungsreagens, das sicher zu handhaben, stabil und hoch reaktiv ist und in der industriellen Produktion als Alternative zum hoch giftigen gasförmigen Fluor eingesetzt werden kann, führte letztlich zur Entwicklung von Selectfluor (1). Dieses Reagens ist eines der reaktivsten elektrophilen Fluorierungsmittel und dazu noch ungefährlich, nicht toxisch und leicht zu handhaben. In diesem Aufsatz beschreiben wir die zahlreichen Einsatzmöglichkeiten von Selectfluor und diskutieren mögliche Reaktionsmechanismen.
Selectfluor: Mechanistic Insight and Applications
Authors: Nyffeler Paul T. , Durón Sergio Gonzalez , Burkart Michael D. , Vincent Stéphane P. , Wong Chi‐Huey
Published: December 2004

The replacement of hydrogen atoms with fluorine substituents in organic substrates is of great interest in synthetic chemistry because of the strong electronegativity of fluorine and relatively small steric footprint of fluorine atoms. Many sources of nucleophilic fluorine are available for the derivatization of organic molecules under acidic, basic, and neutral conditions. However, electrophilic fluorination has historically required molecular fluorine, whose notorious toxicity and explosive tendencies limit its application in research. The necessity for an electrophilic fluorination reagent that is safe, stable, highly reactive, and amenable to industrial production as an alternative to very hazardous molecular fluorine was the inspiration for the discovery of selectfluor. This reagent is not only one of the most reactive electrophilic fluorinating reagents available, but it is also safe, nontoxic, and easy to handle. In this Review we document the many applications of selectfluor and discuss possible mechanistic pathways for its reaction.
Self‐aggregates of cholic acid hydrazide–dextran conjugates as drug carriers
Authors: Xu Qingguo , Yuan Xubo , Chang Jin
Published: December 2004

Cholic acid hydrazide–dextran conjugates (CAH–DEX's) with stable acryl hydrazone linkages were synthesized from cholic acid hydrazide and poly(aldehyde dextran) and were characterized by Fourier transform infrared (FTIR) spectroscopy, 1H‐NMR, and surface tension measurements. The conjugates developed a lower critical aggregation concentration, which was determined by 1,6‐diphenyl‐1,3,5‐hexatriene dye solubilization methods, 1.41 and 2.10 × 10−2 mg/mL for CAH–DEX 9.0 and CAH–DEX 6.5, respectively. A hydrophobic drug, indomethacin (IN), was physically entrapped inside the self‐aggregates, and the IN‐loaded self‐aggregates were analyzed with a dynamic light‐scattering system, transmission electron microscopy, and atomic force microscopy. The maximum loading of IN reached 29.9% of the CAH–DEX self‐aggregates, which suggested a high loading efficiency of 51.2%. The size of the self‐aggregates increased when the drug was entrapped. IN was released from CAH–DEX self‐aggregates at pH 4 much slower than at pH 7.4, and in pH 4 media, the release profile was pseudo‐zero‐order in kinetic terms for up to 14 days. There was almost no change in the FTIR spectra of the CAH–DEX's, which were incubated in buffers of pH 7.4 and pH 4 for 24 h, which indicated that acryl hydrazone was considerably resistant to hydrolysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 487–493, 2005
Synthesis, characterization, and performance evaluation of hard, anticorrosive coating materials derived from diglycidyl ether of bisphenol A acrylates and methacrylates
Authors: Ahmad Sharif , Ashraf S. M. , Hassan S. N. , Hasnat Abul
Published: December 2004

Diglycidyl ether of bisphenol A acrylate (DAC) and diglycidyl ether of bisphenol A methacrylate (DMAC) were synthesized by the reaction of an epoxy [diglycidyl ether of bisphenol A (DGEBA)] with acrylic acid and methacrylic acid, respectively. The synthesized resins were characterized by determination of the acid, hydroxyl, and saponification values. Structure elucidation was done by gel permeation chromatography, Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and 13C‐NMR spectroscopy. DACs were cured with melamine formaldehyde resin at low pH values. The pH of the resin systems was adjusted with phosphoric acid. The coatings of these systems were formed on mild steel specimens for physicomechanical and chemical/corrosion‐resistance performance. The coatings of DAC and DMAC showed excellent scratch hardness and good impact‐resistance performance. The coatings of DMAC showed better performance than DAC with respect to chemical and corrosion resistance. Thermogravimetric analysis and differential scanning calorimetry were used to investigate the thermal stability and curing behavior of these systems. DAC showed a little higher glass‐transition temperature than DMAC and also showed a higher thermal resistivity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 494–501, 2005
Molecular design of reactive amphiphilic phospholipid polymer for bioconjugation with an enzyme
Authors: Miyamoto Daisuke , Watanabe Junji , Ishihara Kazuhiko
Published: December 2004

Water‐soluble amphiphilic phospholipid random copolymers such as poly(2‐methacryloyloxyethyl phosphorylcholine (MPC)‐random‐n‐butyl methacrylate (BMA)) and block‐type polymer, poly(MPC‐block‐BMA) (Mw = 1.0 × 104) with a carboxylic group on a terminal, were designed by photoinduced living radical polymerization. These polymers and poly(MPC) were conjugated to an enzyme, papain. The effects of BMA units in the polymers on the enzymatic activity and stability were investigated. The modification degrees of papain with poly(MPC‐random‐BMA) and poly(MPC‐block‐BMA) were 16–19% versus the total number of amino groups in native papain. The remaining α‐helix content of papains conjugated with poly(MPC‐random‐BMA) and poly(MPC‐block‐BMA) was maintained, but the remaining activity of the papains decreased with an increase in the composition of BMA units in the polymers. These activities were small compared to the papain conjugated to poly(MPC). However, the papains conjugated with poly(MPC‐random‐BMA) with 50% BMA units and poly(MPC‐block‐BMA) with 5% BMA units in the near side of the papain maintained much higher enzymatic activity for 28 days at 40°C compared with the papains conjugated with the other polymers. Moreover, the α‐helix content of the papains conjugated with the polymers was maintained at the initial level for 28 days at 40°C. We concluded that the MPC polymers, which contain BMA units, could effectively enhance the stability of papain by controlling the sequence of monomer units and the composition of BMA units in the polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 615–622, 2005