bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of ceramide glucosyltransferases, which are essential for glycosphingolipid synthesis, is only required in a small subset ofC. eleganscells
Authors: Marza Esther , Simonsen Karina T. , Færgeman Nils J. , Lesa Giovanni M.
Published: February 2009

Glycosphingolipids (GSLs) are glycosylated derivatives of ceramide in the lipid bilayer. Their ubiquitous distribution and complexity suggest that they have important functions, but what these are in vivo is still poorly understood. Here, we characterize the phenotype of Caenorhabditis elegans mutants with essentially no GSLs. The C. elegans genome encodes three ceramide glucosyltransferase (CGT) genes, which encode enzymes required for GSL biosynthesis. Animals lacking CGT do not synthesize GSLs, arrest growth at the first larval stage, and display defects in a subset of cells in their digestive tract; these defects impair larval feeding, resulting in a starvation-induced growth arrest. Restoring CGT function in these digestive tract cells – but not in a variety of other tissues – is sufficient to rescue the phenotypes associated with loss of CGT function. These unexpected findings suggest that GSLs are dispensable in most C. elegans cells, including those of the nervous system.
Web-based survey on the effect of menopause on women's libido in a computer-literate population
Authors: Cumming Grant P , Currie Heather D , Moncur Rik , Lee Amanda J
Published: February 2009

Objective

The objective of this study is to use the internet to survey the effect of menopause on women's experience of libido.

Study design

A questionnaire incorporating the Brief Profile of Female Sexual Function (B-PFSF) on a UK menopause website.

Main outcome measure

Questions on reduced libido, distress, level of help sought and treatment.

Results

Eighty-four percent of women ( n = 2112/2527) felt that an active sex life was important. One thousand and fifty-one perimenopausal and 560 postmenopausal women reported reduced libido causing distress with 23% and 35% discussing this with health professionals. Eighteen percent perimenopausal and 30% postmenopausal women had tried non-testosterone hormone replacement therapy with 34% and 37%, respectively, finding it helpful. Testosterone was deemed useful in some perimenopausal ( n = 6/17) and postmenopausal ( n = 23/50) women. Twenty-seven percent premenopausal, 38% perimenopausal and 56% postmenopausal women reported vaginal dryness with 78% peri- and 87% postmenopausal women believing it a factor causing reduced libido. Twenty-two percent premenopausal, 28% perimenopausal and 46% postmenopausal women had discussed this with health professionals and 17%, 36% and 55%, respectively, were on treatment. Women in all reproductive epochs completed the B-PFSF (a validated tool for postmenopausal women only).

Conclusions

An active sex life was deemed to be important but many women were not seeking help for menopause-related reduced libido causing distress. For many, vaginal changes contributed to their symptoms. In those seeking advice, treatment was commonly not prescribed. Health professionals must ask appropriate direct questions to all women, especially as part of menopausal assessment. A need for the B-PFSF to be validated in non-postmenopausal women was also indicated.
Menopause, cognitive ageing and dementia: practice implications
Authors: Henderson Victor W
Published: February 2009

Episodic memory is affected by cognitive ageing, and memory impairment beyond that expected on the basis of usual ageing may be an early indicator of Alzheimer's disease. Although memory complaints are common in midlife, it is reassuring that the natural menopausal transition is unaccompanied by objective memory loss. Less is known about memory after surgical menopause. Estrogen-containing hormone therapy initiated during the late postmenopause increases dementia risk and does not improve memory. It is unclear whether hormone use during the menopausal transition or early postmenopause affects Alzheimer risk. Observational studies imply a protective association consistent with the so-called critical window hypothesis, but these findings could be biased. Clinical practice implications are presented.
Designing clinical trials of homeopathy for menopausal symptoms: a review of the literature
Authors: Thompson Elizabeth A , Relton Clare
Published: February 2009

Homeopathy is a system of therapeutics placed outside the boundaries of orthodox medicine and regarded as a complementary and alternative medicine. Homeopathy has been used to alleviate menopausal symptoms both in the climacteric and in breast cancer survivors. Individualized treatment by a homeopath, regarded as the gold standard of homeopathic care, is a complex intervention where the homeopathic medicine is matched to the individual using holistic principles. This review article describes and interprets the existing evidence from observational studies and clinical trials and makes recommendations for trial design in the future.
A Conic Duality Frank–Wolfe-Type Theorem via Exact Penalization in Quadratic Optimization
Authors: Schachinger Werner , Bomze Immanuel
Published: February 2009

The famous Frank–Wolfe theorem ensures attainability of the optimal value for quadratic objective functions over a (possibly unbounded) polyhedron if the feasible values are bounded. This theorem does not hold in general for conic programs where linear constraints are replaced by more general convex constraints like positive semidefiniteness or copositivity conditions, despite the fact that the objective can be even linear. This paper studies exact penalizations of (classical) quadratic programs, i.e., optimization of quadratic functions over a polyhedron, and applies the results to establish a Frank–Wolfe-type theorem for the primal-dual pair of a class of conic programs that frequently arises in applications. One result is that uniqueness of the solution of the primal ensures dual attainability, i.e., existence of the solution of the dual.
Online Scheduling with Known Arrival Times
Authors: Hall Nicholas G. , Posner Marc E. , Potts Chris N.
Published: February 2009

We consider an online scheduling environment where decisions are made without knowledge of the data of jobs that may arrive later. However, additional jobs can only arrive at known future times. This environment interpolates between the classical offline and online scheduling environments and approaches the classical online environment when there are many equally spaced potential job arrival times. The objective is to minimize the sum of weighted completion times, a widely used measure of work-in-process inventory cost and customer service. For a nonpreemptive single machine environment, we show that a lower bound on the competitive ratio of any online algorithm is the solution of a mathematical program. This lower bound is between (1 + SQRT(5))/2 and 2, with the exact value depending on the potential job arrival times. We also provide a “best possible” online scheduling algorithm and show that its competitive ratio matches this lower bound. We analyze two practically motivated special cases where the potential job arrival times have a special structure. When there are many equally spaced potential job arrival times, the competitive ratio of our online algorithm approaches the best possible competitive ratio of 2 for the classical online problem.
Comment on “Investment Timing Under Incomplete Information”
Authors: Klein Manuel
Published: February 2009

In a recent contribution to this journal, Décamps et al. [Décamps, J.-P., T. Mariotti, S. Villeneuve. 2005. Investment timing under incomplete information. Math. Oper. Res. 30(2) 472–500] analyze the decision of when to invest in a project whose value is perfectly observable but driven by a parameter that is unknown to the decision maker ex ante. Using filtering and martingale techniques, they find that (i) the decision maker always benefits from an uncertain drift relative to an average drift situation, and (ii) drift uncertainty unambiguously delays investment. Using the principle of smooth fit, I derive an analytical solution to the problem and give a numerical example that shows that both claims do not hold true in general. My analysis shows that the impact of drift uncertainty on the value of the option to invest and the optimal timing of investment is governed by two separate effects: the impact of uncertainty per se and the impact of learning. In particular, the results of Décamps et al. only hold true if the latter outweighs the former.
Investment Timing Under Incomplete Information: Erratum
Authors: Décamps Jean-Paul , Mariotti Thomas , Villeneuve Stéphane
Published: February 2009

In this note, we point out a mistake in the proof of Theorem 5.1 in Décamps et al. [Décamps, J.-P., T. Mariotti, S. Villeneuve. 2005. Investment timing under incomplete information. Math. Oper. Res. 30 472–500].
Generating a Representative Subset of the Nondominated Frontier in Multiple Criteria Decision Making
Authors: Karasakal Esra , Köksalan Murat
Published: February 2009

In this paper, we address the problem of generating a discrete representation of the nondominated frontier in multiple objective linear problems. We find a surface that approximates the shape of the nondominated frontier. Utilizing the surface, we generate a set of discrete points that is representative of the frontier. Our experience on randomly generated problems demonstrates that the approach performs well in terms of both the quality of the representation and the computation time.
Technical Note—Approximating Vehicle Dispatch Probabilities for Emergency Service Systems with Location-Specific Service Times and Multiple Units per Location
Authors: Budge Susan , Ingolfsson Armann , Erkut Erhan
Published: February 2009

To calculate many of the important performance measures for an emergency response system, one requires knowledge of the probability that a particular server will respond to an incoming call at a particular location. Estimating these “dispatch probabilities” is complicated by four important characteristics of emergency service systems. We discuss these characteristics and extend previous approximation methods for calculating dispatch probabilities to account for the possibilities of workload variation by station, multiple vehicles per station, call- and station-dependent service times, and server cooperation and dependence.
Stochastic Power Generation Unit Commitment in Electricity Markets: A Novel Formulation and a Comparison of Solution Methods
Authors: Cerisola Santiago , Baíllo Álvaro , Fernández-López José M. , Ramos Andrés , Gollmer Ralf
Published: February 2009

We propose a stochastic unit commitment model for a power generation company that takes part in an electricity spot market. The relevant feature of this model is its detailed representation of the spot market during a whole week, including seven day-ahead market sessions and the corresponding adjustment market sessions. The adjustment market sessions can be seen as an hour-ahead market mechanism. This representation takes into account the influence that the company's decisions exert on the market-clearing price by means of a residual demand curve for each market session. We introduce uncertainty in the form of several possible spot market outcomes for each day, which leads to a weekly scenario tree. The model also represents in detail the operation of the company's generation units.

The model leads to large-scale mixed linear-integer problems that are hard to solve with commercial optimizers. This suggests the use of alternative solution methods. We test four solution approaches with a realistic numerical example in the context of the Spanish electricity spot market. The first is a direct solution with a commercial optimizer, which illustrates the mentioned limitations. The second is a standard Lagrangean relaxation algorithm. The third and fourth methods are two original variants of Benders decomposition for multistage stochastic integer programs. The first Benders decomposition algorithm builds approximations for the recourse function relaxing the integrality constraints of the subproblems. The second variant strengthens these cuts by performing one iteration of the Lagrangean of each subproblem. We analyze the advantages of these four methods and compare the results.
Investigating Braess' Paradox with Time-Dependent Queues
Authors: Lin Wei-Hua , Lo Hong K.
Published: February 2009

In the 1960s, Braess showed that the overall system performance of a transportation network can be degraded when a new link is added to the network, given that travelers choose their routes based on the user equilibrium (UE) principle. This phenomenon is often referred to as Braess' paradox (BP). The original five-link BP network has been studied extensively with static link performance functions. In this paper, we revisit the original BP network with a dynamic point-queue model and examine whether the results from the static model would hold for the case with time-dependent queues. For this purpose, we solve the BP problem with the consideration of dynamic queuing that leads the system to a steady state while satisfying the dynamic user equilibrium (DUE) condition at every instant. Our results indicate that the locations of congestion, or “hot spots,” of the system are sensitive to the capacity of each link in an intricate manner. The “surprising result” reported in previous studies with link performance functions, that a system can spontaneously grow out of Braess' paradox if the demand is sufficiently high, does not occur with time-dependent queues. Instead, we show that queues in different stages have different impacts on the system performance. The implication of this result is discussed in the context of developing proactive dynamic traffic control strategies that can eliminate the negative impact of BP while keeping the system operating at the DUE condition. Even though this study focuses on the original five-link network, the results illustrate the potential pitfalls of extending insights developed from a static framework for dynamic traffic and the importance of studying the problem with a dynamic framework for real-time traffic control.
Recent applications of imines as key intermediates in the synthesis of alkaloids and novel nitrogen heterocycles
Authors: Martin Stephen F.
Published: February 2009

One of the major challenges in contemporary synthetic organic chemistry is the design and development of new tactics and strategies and their application to concise and efficient syntheses of biologically active natural products. Strategies that utilize reactions that enable the rapid assembly of the skeletal framework of such targets are thus especially attractive. In this context, we have developed novel applications of imine chemistry in Mannich and related reactions, cascade processes, and multicomponent reactions (MCRs) to rapidly assemble structural subunits common to diverse families of alkaloids. The practical utility of these chemistries is evidenced by their use in the execution of facile total syntheses of (±)-epilupinine (1), (±)-tashiromine (2), (-)-epimyrtine (3), and (±)-roelactamine (4) as well as other nitrogen heterocycles of potential biological interest.
Indium-catalyzed Conia-ene reaction for alkaloid synthesis
Authors: Hatakeyama Susumi
Published: February 2009

In(OTf)3-catalyzed cyclization of nitrogen- and oxygen-tethered acetylenic malonic esters provides various five- to seven-membered heterocycles in moderate to excellent yield, and the reaction proceeds with no racemization and complete E-selectivity in the case of chiral and nonterminal alkynes. The synthetic utility is demonstrated by the synthesis of (-)-salinosporamide A, a highly potent 20S proteasome inhibitor, and (+)-neooxazolomycin, a member of the oxazolomycin family of antibiotics.
Studies for the synthesis of marine natural products
Authors: Williams David R. , Walsh Martin J. , Claeboe Christopher D. , Zorn Nicolas
Published: February 2009

The process of allylic transposition in SE' reactions is a significant construct for synthesis. The flexibility of a variety of allylation strategies provides for the rational design of pathways to a diverse array of complex targets. Our recent studies of SE' reactions will examine issues of stereoselectivity and efficiency in the context of applications toward the synthesis of marine natural products such as the xenicane diterpenes, which feature the strained E-cyclononene ring system, and peloruside A, a 16-membered macrocyclic lactone.
1-Lithio-1,3-dienes as useful building blocks in organic synthesis
Authors: Zhang Wen-Xiong , Xi Zhenfeng
Published: February 2009

Both intermolecular reactivities toward C-O and C-N unsaturated substrates and intramolecular reactions of various 1-lithio-1,3-dienes are briefly summarized. Results reveal that intramolecular synergy between the alkenyllithium moiety and the butadienyl skeleton make 1-lithio-1,3-diene derivatives useful and unique as building blocks in organic synthesis. It is demonstrated that substitution patterns and the nature of the substituents on the butadienyl skeleton have remarkable effects on reaction pathways.
Dispersity in polymer science (IUPAC Recommendations 2009)
Authors: Stepto Robert F. T.
Published: February 2009

This recommendation defines just three terms, viz., (1) molar-mass dispersity, relative-molecular-mass dispersity, or molecular-weight dispersity; (2) degree- of-polymerization dispersity; and (3) dispersity. "Dispersity" is a new word, coined to replace the misleading, but widely used term "polydispersity index" for M
w/M
n and X
w/X
n. The document, although brief, also has a broader significance in that it seeks to put the terminology describing dispersions of distributions of properties of polymeric (and non-polymeric) materials on an unambiguous and justifiable footing.
Teaching high-temperature materials chemistry at university (IUPAC Technical Report)
Authors: Balducci Giovanni , Ciccioli Andrea , de Maria Giovanni , Hoda Fiqiri , Rosenblatt Gerd M.
Published: February 2009

Over the last four to five decades, high-temperature materials chemistry (HTMC) has become a flourishing area of scientific and applied research, spurred by both a growing demand for new inorganic materials (e.g., oxide and non-oxide modern multifunctional ceramics, intermetallics, and oxidation-resistant alloys) able to withstand extreme thermal and chemical environments and by the recognition that chemical and physical behavior at high temperatures differs from, and cannot be extrapolated from, behavior at temperatures near room temperature. Despite the important role played by HTMC in modern advanced technology and the fundamental differences in behavior encountered at high temperatures, HTMC topics are rarely covered in chemistry and materials science programs at the university level because of a lack of readily accessible resource material - no textbook exists specifically devoted to HTMC topics. IUPAC's Inorganic Chemistry Division sponsored a project to address this gap, resulting in the present report. The report includes an introduction and seven sections covering historical background, chemical behavior of condensed-phase/gas-phase systems at high temperature, basic concepts of materials thermodynamics, experimental techniques, use of thermodynamic data and modeling, vaporization, and decomposition processes, and gas-solid reactions. The ninth section covers more specific topics, primarily concerning applications of high-temperature materials and processes. Each recommended topic is accompanied by a bibliography of helpful references, a short introduction or explanation including the areas of application, and some relevant teaching suggestions. An extensive annotated resource bibliography is an Appendix to the report available as supplementary material.
Countercurrent chromatography in analytical chemistry (IUPAC Technical Report)
Authors: Berthod Alain , Maryutina Tatyana , Spivakov Boris , Shpigun Oleg , Sutherland Ian A.
Published: February 2009

Countercurrent chromatography (CCC) is a generic term covering all forms of liquid-liquid chromatography that use a support-free liquid stationary phase held in place by a simple centrifugal or complex centrifugal force field. Biphasic liquid systems are used with one liquid phase being the stationary phase and the other being the mobile phase. Although initiated almost 30 years ago, CCC lacked reliable columns. This is changing now, and the newly designed centrifuges appearing on the market make excellent CCC columns. This review focuses on the advantages of a liquid stationary phase and addresses the chromatographic theory of CCC. The main difference with classical liquid chromatography (LC) is the variable volume of the stationary phase. There are mainly two different ways to obtain a liquid stationary phase using centrifugal forces, the hydrostatic way and the hydrodynamic way. These two kinds of CCC columns are described and compared. The reported applications of CCC in analytical chemistry and comparison with other separation and enrichment methods show that the technique can be successfully used in the analysis of plants and other natural products, for the separation of biochemicals and pharmaceuticals, for the separation of alkaloids from medical herbs, in food analysis, etc. On the basis of the studies of the last two decades, recommendations are also given for the application of CCC in trace inorganic analysis and in radioanalytical chemistry.
Guidelines for rheological characterization of polyamide melts (IUPAC Technical Report)
Authors: Dijkstra Dick J.
Published: February 2009

Most producers of polyamide have their own characterization method to study the rheological properties of polyamide 6 (PA6). However, the measured rheological properties depend strongly on the sample preparation method, humidity regulation, and time-temperature history during the measurement and not least on the kind of rheometer being used. This investigation is the result of an IUPAC project initiated by the Subcommittee on Structure and Properties of Commercial Polymers. Members of several industrial organizations, universities, and institutes cooperated, with the aim of formulating a guideline to measure reproducible rheological properties of PA6. The results of the investigation show the changes in molecular weight during different kinds of rheological measurements due to hydrolysis and amidization reactions. A guideline is introduced which can be used to make comparable rheological measurements on PA6.
Measurements of Elastic Properties of Geomaterials in Laboratory Compression Tests
Authors: Tatsuoka F , Sato T , Park C-S , Kim Y-S , Mukabi JN , Kohata Y
Published: February 2009

Two types of axial loading devices having high and low capacities of axial load, respectively, for use in displacement-controlled compression tests on geomaterials (i.e., natural soils and rocks, and treated soils) in the laboratory are described. They were designed so that the loading direction can be reversed without any noticeable time lag under a highly constant axial strain rate while using a gear system. Results of representative triaxial and plane strain compression tests on a sand, a sedimentary soft rock, and a clay are presented. These results were obtained from very slow monotonic (or one-way) loading tests with several unload/reload cycles measuring axial strains locally along the lateral surfaces of a specimen continuously for a strain range from the order of 0.0001% (10−6) to that at failure. It is demonstrated that initial stiffness at strains less than about 0.001% (10−5) during primary loading is the same as stiffness during small unload/reload cycles applied immediately after the start of loading. Initial deformation properties are rather linear and elastic.
Impact-Echo Response of Hollow Cylindrical Concrete Structures Surrounded by Soil and Rock: Part II—Experimental Studies
Authors: Lin J-M , Sansalone M
Published: February 2009

The studies summarized in this paper demonstrate that the impact-echo method can be used for integrity testing of mine shaft and tunnel liners in contact with rock. Results obtained from experimental studies on mine shaft liners are presented. These results show that the measured impact-echo response depends upon the acoustic properties of the surrounding material as well as the acoustic properties and condition of the concrete structure. It is shown that cracks and voids in the concrete structure can be detected independent of the surrounding material. If the concrete structure is solid, the thickness of the concrete can be determined, except when the acoustic properties of the rock and concrete are similar and the concrete is bonded to the rock. The presence of delaminations or voids (either air- or water-filled) at the concrete/rock interface can be identified when the acoustic properties of the rock are similar or larger than those of the concrete.
Effect of Simulated Roots on the Permeability of Silty Soil
Authors: Gabr MA , Akram M , Taylor HM
Published: February 2009

A preliminary laboratory testing program was conducted to investigate the potential effect of vegetation on the hydraulic conductivity of soils used to construct levee structures. The testing program was conducted using a silty sand soil with a simulated root system. Testing apparatus included rigid-wall-double-ring permeameters and flexible-wall permeameters. The simulated roots were made using Balsa wood having a square cross section of 1.65 by 1.65 mm and approximately 12 to 25 mm in length. The measured hydraulic conductivity for specimens without simulated roots decreased as a function of the moisture content from approximately 1 × 10-3 cm/s to 5 × 10-4 cm/s. Values obtained using the flexible-wall device were less than those measured using the rigid-wall device by a factor of approximately 2. The addition of 1% simulated roots decreased the measured hydraulic conductivity, k. The reduction in k increased from less than 10% at a molding water content of 10% to approximately 50% at a water content of 25%. Similar behavior was observed in the case of specimens with 2% simulated roots. For γdry of 10 kN/m3, the estimated k values were 1 × 10-5 cm/s for the case of 2% roots versus 3 × 10-4 cm/s for the case of 1% roots. The k values decreased as the unit weight of the specimens was increased for both cases. In addition, the difference between k values obtained for specimens containing 1% and specimens containing 2% simulated roots increased as the dry unit weight of the specimens was increased.
Split-Hopkinson Pressure Bar Testing of Unsaturated Sand
Authors: Charlie WA , Ross CA , Pierce SJ
Published: February 2009

High amplitude, split-Hopkinson pressure bar (SHPB) laboratory tests were conducted on compacted specimens of 50/80 silica sand to evaluate the influence of saturation on compressional-stress wave velocity, stress transmission, and attenuation. Stress wave velocity and transmitted stress increase as the saturation increases from 0 to 30 to 40% for constant input stress and constant dry density. At saturation levels between 40 to 95%, both the wave speed and the transmitted stress decrease with increasing saturation. Quasistatic confined modulus show similar trends. These trends may be explained by capillary pressure.
Reinforcing Soil with Aligned and Randomly Oriented Metallic Fibers
Authors: Fatani MN , Bauer GE , Al-Joulani N
Published: February 2009

Laboratory direct shear box tests were used to evaluate the strength behavior of a reinforced uniform silty sand. The reinforcement elements consisted of flexible, semirigid, and rigid metallic fibers. The orientations of the fibers to the shear plane were varied and had a marked effect on the shear resistance. Increases in peak and residual strengths of 100 and 300%, respectively, were observed over unreinforced sand. Specimens reinforced with randomly oriented flexible fibers also exhibited a similar improvement of strength parameters.
Clay Lumps under Simulated Hydraulic Transport Conditions
Authors: Leshchinsky D , Richter SD , Fowler J
Published: February 2009

Laboratory experiments with compacted kaolinite-bentonite mixtures indicate that degradation of hydraulically transported clay lumps in a dredge pipeline can be predicted and controlled to some extent. The size reduction of these lumps depends not only on the length of the pipeline but also on the density of the clay being dredged, the plasticity index (PI) of the clay, and the velocity of the dragging slurry in the pipe. A series of graphs shows percent reduction in clay lumps as a function of PI and velocity at three levels of relative compacted density.

If the relationships obtained in this study are shown to be valid in the field, this information will be useful in selecting dredging equipment, designing dredged material containment area, and estimating costs. Relatively undisturbed specimens of the in situ clay and simple laboratory tests would provide the necessary information.
The Measurement of Stiffness Anisotropy in Clays with Bender Element Tests in the Triaxial Apparatus
Authors: Jovičić V , Coop MP
Published: February 2009

The paper presents the results of a program of research investigating the effectiveness of bender elements when used in conjunction with the triaxial apparatus for measuring the anisotropy of small strain stiffness of fine-grained soils. Tests were carried out on both intact and reconstituted samples of London clay and on kaolin up to high stresses. The paper shows that the transverse isotropy of small-strain stiffness that commonly occurs in many soils because of a one-dimensional loading history can be fully investigated in the conventional triaxial apparatus and that London clay is an example of such a soil. The stress-induced component of anisotropy was found to be very small for axi-symmetric loading conditions common to both the appartus and the in situ state of these soils. In contrast, the inherent or structural anisotropy was much more significant and is shown to be a variable factor resulting from the plastic strain history and is not related to its natural structure. Consequently, inherent anisotropy is reversible, but the rate of change is very slow when a new regime of stresses is imposed. Inherent anisotropy of the very small strain stiffness also persists long after the plastic strains of the soil have become oriented toward the new stresses.
On Some Issues in Triaxial Extension Tests
Authors: Wu W , Kolymbas D
Published: February 2009

Results of triaxial extension tests on dry sand are presented. Special attention is paid to the factors influencing the results in triaxial extension tests. It is found that factors such as accuracy of the axial force measurement, axial force carried by the rubber membrane surrounding the specimen, gravity, and inhomogeneous deformation have a much larger influence on the results in triaxial extension tests than in triaxial compression tests. Accurate measurement of the axial force is achieved by placing the load cell inside the pressure chamber. The influence of the confining pressure on the axial force measurement is avoided through a proper construction. The force carried by the rubber membrane is corrected with reference to the result of a tension test on a strip of rubber membrane. The effect of gravity is accounted for by adding the axial stress due to gravity to the applied axial stress. The inhomogeneous deformation is traced by three lateral strain collars placed along the specimen height. Results of triaxial extension tests cannot be appreciated if these influential factors are not taken into account.

The failure mode of the specimen is found to be influenced largely by the initial density. Inhomogeneous deformation in the form of necking develops in the upper part of dense specimens and in the middle of loose specimens. For dense specimens, the necked region becomes wider with advanced deformation and develops into one single or two intersecting shear bands. For loose specimens, however, no shear bands can be observed.
The Toluene and Wax-Freezing Method of Determining Volumetric Free Swell
Authors: Pellissier JP
Published: February 2009

Swelling clay and rock are a common problem worldwide, and for design purposes it is necessary to quantify the free-swell behaviour of such material. A technique to measure the volumetric free swell of a swelling clay (called the toluene and wax-freezing volumetric free-swell method) is suggested here and consists of two approaches to measuring the volume of a specimen at different moisture contents. Both approaches have certain limitations, but fortunately they complement each other.

The author required a volumetric free-swell method which could be performed with practically zero external load on the sample during free swell and where the scatter in the recorded results would be low. An optional requirement was that one should be able to perform the test in a field laboratory with only a few samples and a minimum of equipment.

The results should be presented in such a way as to make interpretation and prediction easy.
Determination of Local Displacements on Soil Samples
Authors: Symes MJ , Burland JB
Published: February 2009

A description is given of two types of laboratory instrumentation suitable for monitoring deformations locally over a central portion of a soil sample. Using this instrumentation the problems caused by apparatus compliance, by bedding of the end caps, and by imposition of zero lateral movement at the ends of the sample (such as in conventional cylindrical tests) are avoided. In this paper the instruments are used to determine the three principal strains in a hollow cylindrical sample, which is subject to different axial, horizontal shear, radial, and circumferential stresses.
A Fast Triaxial Shear Device
Authors: Carroll WF
Published: February 2009

The fast triaxial shear device (FTRXD) loads a 1.9-cm (0.75-in.) diameter by 3.8-cm (1.5-in.) long soil specimen, deforming it axially at a very rapid rate. The specimen is deformed by a piston-cylinder assembly driven by compressed nitrogen. Load and displacement at the top of the specimen and load at the bottom are measured; the specimen is subjected to a confining pressure up to 6.9 MPa (1000 psi). The shortest times to failure to date have been 0.5 ms. Soil from the CARES-Dry Luke Gunnery Range in Arizona was used in the evaluation. It is a clayey sand (SC) in the Unified Soils Classification System. The moving upper load cell is sensitive to specimen inertia and FTRXD dynamics; the stationary lower load cell is much less so. Both load measurements and the displacement of the specimen top are needed for wave analyses of the specimen and assessment of FTRXD dynamics.
Design and Performance of Soil-Pile-Slip Test Apparatus for Tension Piles
Authors: Reddy ES , Chapman DN , O'Reilly M
Published: February 2009

The T-Z method is the common method available to estimate load-displacement behavior of tension piles. Obtaining accurate T-Z curves from laboratory tests has a vital role in better estimation of pile behavior. The available apparatus used to obtain laboratory T-Z curves (Coyle and Sulaiman 1967) suffers from a set of limitations.

A soil-pile-slip test apparatus has been designed at the University of Nottingham (UK) to obtain better T-Z curves for tension piles. This paper presents the design details and the testing procedure of the soil-pile-slip test apparatus. A set of T-Z curves obtained using this apparatus is analyzed, which provides insight into the mechanism of soil-pile-slip dilation near the pile surface.
Some Observations on the Laboratory Measurement of Soil-Geotextile Bond
Authors: Ingold TS
Published: February 2009

To determine soil-geotextile bond the engineer has, at present, two main test techniques, namely, the shear box and the pull-out test. A comparison of results for these two techniques has been made for three geotextiles, two fabrics and one grid, that have been used in the United Kingdom as soil reinforcement. Four test techniques have been employed, three based on the shear box and the fourth, a pull-out test. The 300- by 300-mm shear box has been used in the fixed shear mode where the geotextile is bonded to a rigid base plate and the free shear mode where the geotextile is clamped to one end of the lower half of the shear box with soil above and below. Use of the 60- by 60-mm shear box has been limited to the fixed shear mode. Analysis of the test results for any one geotextile show that the shear box results are in good agreement with one another. In most cases the angle of bond stress is independent of normal stress level. A quite different result was obtained for the pull-out test; the angle of bond stress decreased with increasing normal stress level. The results are discussed in detail and it is concluded that although the shear box test technique might prove useful as an index test the pull-out test, even with only qualitative interpretation, is the most suitable for systems testing by virtue of its ability to detect faults in the structure of the geotextile.
Soil Remolding and Sensitivity Measurements
Authors: Yong RN , Tang KY
Published: February 2009

This study examines the problem of measurement of soil sensitivity and the significance of soil remolding effects on the “remolded” strength of soil. A simple shear device has been adapted to provide a means for both soil remolding and continuous measurement of shear stress and strain using cyclic stress reversals. Computations can be made to relate soil remolding and input energy for correlation with measured remolded soil strength using the simple shear device.
A Servo System for Hollow Cylinder Testing of Soils
Authors: Shibuya S
Published: February 2009

A fully digitized servo-control system, coupled with the automatic data acquisition facility, has been developed for a hollow cylinder apparatus (HCA). The closed-loop servo-control is based on a computer through which four individual stresses acting on the hollow cylindrical specimen can be independently changed using pneumatic regulators driven by stepper motors. The range of tests that can be performed in the HCA is considerably expanded to include boundary displacement controlled tests, as well as genuine stress controlled tests under generalized stress conditions involving principal stress rotation. This paper describes the detailed features both of the hardware and software of the servo-system. The experimental capabilities of the servo-system, together with its limitations, are discussed using test results that deal with particular aspects of the stress and strain paths associated with in-situ and laboratory loading.
Prediction of Field Compressibility from Laboratory Consolidation Tests of Peats and Organic Soils
Authors: Stinnette P
Published: February 2009

Gibson and Lo (1961) compressibility parameters a and b for an organic soil can be determined from the organic content and the current pressure using the model presented by Gunaratne et al. (1998). These parameters, however, were developed based on results of laboratory one-dimensional consolidation tests and are valid for the K0 state. Researchers such as Edil et al. (1984) have found that the experimentally determined values of b in particular are larger for field situations. Therefore, the compressibility parameters have to be modified to predict field settlement under surcharges. This paper describes an extended model that addresses this issue and demonstrates how the laboratory-based b value can be corrected for field loading conditions. Finally, results of a full-scale, instrumented field settlement study of organic soil are shown to correlate well with the predictions of the extended model.
Effects of Non-Plastic Fines on Minimum and Maximum Void Ratios of Sand
Authors: Lade PV , Liggio CD , Yamamuro JA
Published: February 2009

The behavior of sand is affected by the content of nonplastic fine particles. How and to what degree the fines content affects the minimum and maximum void ratios has been studied in detail. A review is presented of previous theoretical and experimental studies of minimum and maximum void ratios of single spherical grains, packings of spheres of several discrete sizes, as well as optimum grain-size ratios to produce maximum densities. A systematic experimental study is performed of the variation of minimum and maximum void ratios with contents of fines for sands with smoothly varying particle size curves and a large variety of size distributions. It is shown that the fines content plays an important role in determining the sand structure and the consequent minimum and maximum void ratios. It is indicated how the fines content and sand structure affects the compressibility and the static liquefaction potential of the sand.
Epidemiologic Features of Kawasaki Disease in Taiwan, 2003–2006
Authors: Huang Wen-Chan , Huang Li-Min , Chang I-Shou , Chang Luan-Yin , Chiang Bor-Luen , Chen Pei-Jer , Wu Mei-Hwan , Lue Hung-Chi , Lee Chun-Yun ,   and the Kawasaki Disease Research Group
Published: February 2009

OBJECTIVE. Kawasaki disease is the leading cause of acquired heart disease in children worldwide. This study characterizes the epidemiology of Kawasaki disease in Taiwan between 2003 and 2006.

METHODS. Using Taiwan's 2003–2006 national health insurance claims, we investigated the epidemiologic features of Kawasaki disease (ICD-9-CM code 446.1) and coronary artery aneurysm formation (International Classification of Diseases, Ninth Revision, Clinical Modification code 414.11) and compared the incidences of these diseases with those occurring between 1996 and 2002 in Taiwan and those reported by other countries.

RESULTS. During our 4-year study period, 3877 children and adolescents <20 years of age were hospitalized for Kawasaki disease. Ninety percent of these children were <5 years of age, and the male/female ratio was 1.62:1. The annual incidence of Kawasaki disease was 153 in 100000 children <1 year of age, 111 in children 1 year of age, 58 in children 2 years of age, 30 in children 3 years of age, 19 in children 4 years of age, and 5.2 in children 5 to 9 years of age. The overall incidence was 69 cases per 100000 for children <5 years of age. Kawasaki disease recurred in 1.5% of all cases. Kawasaki disease occurred most frequently in the summer and least frequently in the winter. Coronary artery aneurysm occurred in 7.2% (279 of 3877) of all Kawasaki disease cases.

CONCLUSIONS. The overall incidence of Kawasaki disease was 69 in 100000 children <5 years of age between 2003 and 2006 in Taiwan, comparable with the incidence of 66 in 100000 children between 1996 and 2002. Taiwan has the third highest incidence of Kawasaki disease in the world, after Japan and Korea. In Taiwan, it occurs more frequently during the summer.
Preparation of Yb-Doped Sc2O3 Transparent Ceramics for Laser Applications
Authors: Longuet Laurence , Bravo Anne-Cecile , Autissier Denis , Vissie Pascal , Longuet Jean-Louis , Lambert Sebastien
Published: February 2009

Polycrystalline transparent Yb:Sc2O3 ceramics were obtained in the best conditions by a solid-state reaction route using high purity Sc2O3 and Yb2O3 powders with TEOS as a sintering aid. The as-prepared powders containing various ytterbium content were characterized by BET measurements, XRD and FEG-SEM. The sintering behaviour of the powders was investigated by dilatometry. The sintered materials microstructures were observed by FEG-SEM. EPMA allowed to characterize the repartition of the dopant Yb3+ in the Sc2O3 matrix.
Phase Equilibria and Crystal Growth for LiREF4 Scheelite Laser Crystals
Authors: Klimm Detlef , Dos Santos Ivanildo A. , Ranieri Izilda M. , Baldochi Sonia L.
Published: February 2009

The scheelite type laser crystals LiREF4 melt congruently only for RE being one of the elements Er, Tm, Yb, Lu, or possibly Y, respectively. For RE = Eu, Gd, Tb, Dy, or Ho the corresponding scheelites undergo a peritectic melting under the formation of the corresponding rare earth fluoride. The melting behavior of LiREF4 mixed crystals with two or more RE is not yet known well. If RE is a mixture of Gd and Lu, Gd rich solid solutions melt peritectically under formation of (Gd,Lu)F3 and Lu rich solid solutions melt directly without formation of other solid phases.
Ferromagnetism and Luminescence of Diluted Magnetic Semiconductors GaGdN and AlGdN
Authors: Emura Shuichi , Takahashi Masahiro , Tambo Hiroyuki , Suzuki Akira , Nakamura Tetsuya , Zhou Yi-Kai , Hasagawa Shigehiko , Asahi Hajime
Published: February 2009

The magnetic characteristics of the dilute magnetic system GaGdN are investigated by mainly soft-X-ray magnetic circular dichroism (MCD) in energy range of 1160 – 1240 eV. The strong MCD signals up to 30 % at 15K are observed. The temperature dependence of its intensity is not on simple Curie-Weiss curve and depicts three-step curve. A step around 40 – 100K suggests a new magnetic phase. The luminescence spectrum of GaGdN at low temperature is divided into three parts consisting of two broad bands around 432 nm and 503 nm and a sharp peak at 652 nm. This sharp line is assigned to the intra-transition of f – f orbital owing to the weak temperature dependence of the intensity and peak position. AlGdN grown by molecular beam epitaxy produces luminescence at 318.5 nm. X-ray absorption fine structure is examined to survey the occupancy of the Gd ion in the grown specimens.
Anomalous Hall Effect in Gd-implanted Wurtzite AlxGa1-xN High Electron Mobility Transistor Structures
Authors: Lo Fang-Yuh , Melnikov Alexander , Reuter Dirk , Cordier Yvon , Wieck Andreas D.
Published: February 2009

AlxGa1-xN/GaN high electron mobility transistor (HEMT) structures grown by ammonia-source molecular beam epitaxy (MBE) are focused-ion-beam implanted with 300 keV Gd-ions at room temperature. The two-dimensional electron gas (2DEG) of these HEMT structures is located 27 nm underneath the sample surface. At 4.2 K, current-voltage characteristics across implanted rectangles show that the structures remain conducting up to a Gd-dose of 1×1012cm-2. Anomalous Hall effect (AHE) is observed at T = 4.2 K for structures implanted with Gd, whose dose is 3×1011cm-2. Measurements of AHE in the wide temperature range from 2.4 K to 300 K show that the magnetic ordering temperature of these structures is around 100 K. Therefore, these Gd-implanted HEMT structures containing the still conducting 2DEG, which is now embedded in a ferromagnetic semiconductor, open the possibility to polarize the electron spins.
Surface Charging of n-type Gd2O3 and HfO2 thin Films
Authors: Wooten David , Losovyj Ya. B. , Petrosky J. , McClory J. , Tang Jinke , Wang Wendong , Dowben Peter A.
Published: February 2009

Gd2O3 and HfO2 films exhibit photovoltaic charging that depends on temperature. The dielectric properties of the surface and concomitant photovoltaic surface charging increases following oxygen exposure under ultrahigh vacuum conditions suggesting that the surface conductivity plays a role in the surface photovoltage charging.
An Amorphous IGZO Rare Earth Doped Luminescent Phosphor
Authors: Wellenius Patrick , Suresh Arun , Muth John F.
Published: February 2009

Indium gallium zinc oxide (IGZO) has attracted recent attention as a high electron mobility amorphous material for high performance thin film transistors and subsequent use in active matrix backplanes for flexible displays. In this study, Eu:IGZO thin films were pulsed laser deposited at room temperature onto sapphire substrates and were investigated by cathodoluminescence and optical transmission. Photoluminescence was not observed with above band gap excitation. Thin film electroluminescent (TFEL) devices were also fabricated from these thin films. The thin films and devices demonstrate characteristic europium emission, with the most intense emission at 611 nm corresponding to the 5D0 to 7F2 transition. Luminescence was observed to increase with increasing oxygen pressure during deposition of the Eu:IGZO thin films and may be related to the free carrier density in the films. The authors believe this to be the first report of an amorphous oxide electroluminescent phosphor.