bluuebunny/crossref_metadata_2025 huggingface dataset:
GGR Critical Review of Analytical Developments in 2004–2005
Authors: Hergt Janet M. , Bédard L. Paul , Deloule Etienne , Jochum Klaus Peter , Linge Kathryn L. , Sylvester Paul J. , Willbold Matthias , Woodhead Jon D.
Published: June 2007

In 2005 Geostandards and Geoanalytical Research embarked upon a new initiative for its readers. Key researchers in various fields of geoanalytical technique development and their application were identified and invited to provide reviews pertinent to their expertise. As noted in the first of these publications “…instead of revisiting the historical context or decades of development in each analytical technique, the goal here has been to capture a snapshot of “hot topics” across a range of fields as represented in the… literature” (Hergt et al. 2005). Rather than prepare an annual review, a decision was taken earlier this year to provide a biennial summary of progress and accomplishments, in this case for the years 2004–2005. The principal techniques employed in Earth and environmental sciences are covered here, and include laser ablation and multicollector ICP‐MS, ICP‐AES, thermal ionisation and secondary ion mass spectrometry, as well as neutron activation analysis, X‐ray fluorescence and atomic absorption spectrometry. A comprehensive review of the development of reference materials, often essential to these techniques, is also provided. The contributions assembled serve both to keep readers informed of advances they may be unfamiliar with, but also as a means of showcasing examples of the breadth and depth of work being conducted in these fields.
2004–2005 Analytical Developments in Secondary Ion Mass Spectrometry
Authors: Deloule Etienne
Published: June 2007

This review of the literature from 2004 and 2005 concerning secondary ion mass spectrometry (SIMS) highlights the contribution the technique has made in the fields of petrology, geochronology, cosmochemistry and material sciences. In petrology, much research was devoted to the measurement of stable isotopes and trace elements by developments in multicollection acquisition, with emphasis on low atomic mass number elements. Elements studied in particular were S (in sulfides), O (in garnets), C (in sedimentary organic matter), Cl (in glasses) and Si. Novel applications of SIMS to geochronology have included the measurement of young zircon grains by the U‐Pb and U‐Th decay methods. An increasing number of studies have combined U‐Pb geochronology with the measurement of trace elements or stable isotopes in zircon.
Isotope Ratio Determination in the Earth and Environmental Sciences: Developments and Applications in 2004/2005
Authors: Woodhead Jon D.
Published: June 2007

This review documents developments and applications in the field of isotope ratio determination, as reflected in the literature for the Earth and environmental sciences for the years 2004 and 2005. The emphasis is largely one on applications, reflecting the enormous diversity of problems to which isotopic analysis is now applied, but seen against a background of rapid change in the uptake of new analytical technologies.
Accurate Isotopic and Concentration Analyses of Small Amounts of Pb Using Isotope Dilution Coupled with the Double Spike Technique
Authors: Kuritani Takeshi , Usui Tomohiro , Yokoyama Tetsuya , Nakamura Eizo
Published: June 2007

A new method has been developed for the simultaneous determination of Pb abundance and Pb isotopic composition with high precision and accuracy for small test portion masses by thermal ionisation mass spectrometry. In this method, a 205pb‐204pb double spike is added to samples prior to the chemical separation of Pb, and the isotopic composition of the spike‐sample mixture is determined rigorously by the double spike technique using a 207Pb‐204Pb spike. The isotopic composition and concentration of Pb in the sample are then obtained by utilising the principle of isotope dilution. Using this technique, replicate determinations of Pb from NIST SRM 981 and GSJ JP‐1 (peridotite; 0.07 μg g−1 Pb) were performed. The measured concentration and isotopic data were identical, within uncertainty, to published data or to data that were determined independently in this study. The application of this method to U‐Pb dating and the determination of the “initial” Pb isotopic composition was also tested. Lead isotopic compositions and the concentrations of Pb, Th and U were determined for a single batch of samples, through the addition of 205pb‐204pb, 230Th and 235U spikes to samples prior to chemical separation. Also in these experiments, we confirmed that this routine gives accurate data for Pb, Th and U concentrations and Pb isotopic compositions.
Myofibre damage in human skeletal muscle: effects of electrical stimulation versus voluntary contraction
Authors: Crameri R. M. , Aagaard P. , Qvortrup K. , Langberg H. , Olesen J. , Kjær M.
Published: June 2007

Disruption to proteins within the myofibre after a single bout of unaccustomed eccentric exercise is hypothesized to induce delayed onset of muscle soreness and to be associated with an activation of satellite cells. This has been shown in animal models using electrical stimulation but not in humans using voluntary exercise. Untrained males (n= 8, range 22–27 years) performed 210 maximal eccentric contractions with each leg on an isokinetic dynamometer, voluntarily (VOL) with one leg and electrically induced (ES) with the other leg. Assessments from the skeletal muscle were obtained prior to exercise and at 5, 24, 96 and 192 h postexercise. Muscle tenderness rose in VOL and ES after 24 h, and did not differ between groups. Maximal isometric contraction strength, rate of force development and impulse declined in the VOL leg from 4 h after exercise, but not in ES (except at 24 h). In contrast, a significant disruption of cytoskeletal proteins (desmin) and a rise of myogenic growth factors (myogenin) occurred only in ES. Intracellular disruption and destroyed Z‐lines were markedly more pronounced in ES (40%) compared with VOL (10%). Likewise, the increase in satellite cell markers [neural cell adhesion molecule (N‐CAM) and paired‐box transcription factor (Pax‐7)] was more pronounced in ES versus VOL. Finally, staining of the intramuscular connective tissue (tenascin C) was increased equally in ES and VOL after exercise. The present study demonstrates that in human muscle, the delayed onset of muscle soreness was not significantly different between the two treatments despite marked differences in intramuscular histological markers, in particular myofibre proteins and satellite cell markers. An increase in tenascin C expression in the midbelly of the skeletal muscle in both legs provides further evidence of a potential role for the extracellular matrix in the phenomenon of delayed onset of muscle soreness.
Soluble erythropoietin receptor is present in the mouse brain and is required for the ventilatory acclimatization to hypoxia
Authors: Soliz Jorge , Gassmann Max , Joseph Vincent
Published: June 2007

While erythropoietin (Epo) and its receptor (EpoR) have been widely investigated in brain, the expression and function of the soluble Epo receptor (sEpoR) remain unknown. Here we demonstrate that sEpoR, a negative regulator of Epo's binding to the EpoR, is present in the mouse brain and is down‐regulated by 62% after exposure to normobaric chronic hypoxia (10% O2 for 3 days). Furthermore, while normoxic minute ventilation increased by 58% in control mice following hypoxic acclimatization, sEpoR infusion in brain during the hypoxic challenge efficiently reduced brain Epo concentration and abolished the ventilatory acclimatization to hypoxia (VAH). These observations imply that hypoxic downregulation of sEpoR is required for adequate ventilatory acclimatization to hypoxia, thereby underlying the function of Epo as a key factor regulating oxygen delivery not only by its classical activity on red blood cell production, but also by regulating ventilation.
Sex‐dependent regulation of hypothalamic neuropeptide Y‐Y1 receptor gene expression in moderate/high fat, high‐energy diet‐fed mice
Authors: Zammaretti Francesca , Panzica Giancarlo , Eva Carola
Published: June 2007

In this study we investigated whether long‐term consumption of a moderate/high fat (MHF), high‐energy diet can affect the gene expression of the Y1 receptor (Y1R) for neuropeptide Y (NPY) in the dorsomedial (DMH), ventromedial (VMH), arcuate (ARC) and paraventricular (PVN) hypothalamic nuclei of male and female Y1R/LacZ transgenic mice, carrying the murine Y1R promoter linked to the LacZ gene. MHF diet‐fed male mice showed an increased consumption of metabolizable energy that was associated with a significant increase in body weight as compared with chow‐fed controls. In parallel, consumption of a MHF diet for 8 weeks significantly decreased Y1R/LacZ transgene expression in the DMH and VMH of male mice whereas no changes were found in the ARC and PVN. Leptin treatment reduced body weight of both MHF diet‐ and chow‐fed male mice but failed to prevent the decrease in Y1R/LacZ transgene expression apparent in the DMH and VMH of male mice after 8 weeks of MHF diet intake. Conversely, no significant changes of metabolizable energy intake, body weight or hypothalamic β‐galactosidase expression were found in MHF diet‐fed female Y1R/LacZ transgenic mice. A gender‐related difference of Y1R/LacZ transgenic mice was also observed in response to leptin treatment that failed to decrease body weight of both MHF diet‐ and chow‐fed female mice. Results herein demonstrate that Y1R/LacZ FVB mice show a sexual dimorphism both on energy intake and on nucleus‐specific regulation of the NPY Y1R system in the hypothalamus. Overall, these results provide new insights into the mechanism by which diet composition affects the hypothalamic circuit that controls energy homeostasis.
Influence of enhanced troponin C Ca2+‐binding affinity on cooperative thin filament activation in rabbit skeletal muscle
Authors: Kreutziger Kareen L. , Gillis Todd E. , Davis Jonathan P. , Tikunova Svetlana B. , Regnier Michael
Published: June 2007

We studied how enhanced skeletal troponin C (sTnC) Ca2+‐binding affinity affects cooperative thin filament activation and contraction in single demembranated rabbit psoas fibres. Three sTnC mutants were created and incorporated into skeletal troponin (sTn) for measurement of Ca2+ dissociation, resulting in the following order of rates: wild‐type (WT) sTnC–sTn > sTnCF27W–sTn > M80Q sTnC–sTn > M80Q sTnCF27W–sTn. Reconstitution of sTnC‐extracted fibres increased Ca2+ sensitivity of steady‐state force (pCa50) by 0.08 for M80Q sTnC, 0.15 for sTnCF27W and 0.32 for M80Q sTnCF27W with minimal loss of slope (nH, degree of cooperativity). Near‐neighbour thin filament regulatory unit (RU) interactions were reduced in fibres by incorporating mixtures of WT or mutant sTnC and D28A, D64A sTnC (xxsTnC) that does not bind Ca2+ at N‐terminal sites. Reconstitution with sTnC: xxsTnC mixtures to 20% of pre‐exchanged maximal force reduced pCa50 by 0.35 for sTnC: xxsTnC, 0.25 for M80Q sTnC: xxsTnC, and 0.10 for M80Q sTnCF27W: xxsTnC. It is interesting that pCa50 increased by ∼0.1 for M80Q sTnC and ∼0.3 for M80Q sTnCF27W when near‐neighbour RU interactions were reduced; these values are similar in magnitude to those for fibres reconstituted with 100% mutant sTnC. After reconstitution with sTnC: xxsTnC mixtures, nH decreased to a similar value for all mutant sTnCs. Altered sTnC Ca2+‐binding properties (M80Q sTnCF27W) did not affect strong crossbridge inhibition by 2,3‐butanedione monoxime when near‐neighbour thin filament RU interactions were reduced. Together these results suggest increased sTnC Ca2+ affinity strongly influences Ca2+ sensitivity of steady‐state force without affecting near‐neighbour thin filament RU cooperative activation or the relative contribution of crossbridges versus Ca2+ to thin filament activation.
Hypothalamic leptin regulation of energy homeostasis and glucose metabolism
Authors: Morton Gregory J.
Published: June 2007

Growing evidence suggests that food intake, energy expenditure and endogenous glucose production are regulated by hypothalamic areas that respond to a variety of peripheral signals. Therefore, in response to a reduction in energy stores or circulating nutrients, the brain initiates responses in order to promote positive energy balance to restore and maintain energy and glucose homeostasis. In contrast, in times of nutrient abundance and excess energy storage, key hypothalamic areas activate responses to promote negative energy balance (i.e. reduced food intake and increased energy expenditure) and decreased nutrient availability (reduced endogenous glucose production). Accordingly, impaired responses or ‘resistance’ to afferent input from these hormonal or nutrient‐related signals would be predicted to favour weight gain and insulin resistance and may contribute to the development of obesity and type 2 diabetes.
Afferent signalling through the common hepatic branch of the vagus inhibits voluntary lard intake and modifies plasma metabolite levels in rats
Authors: Warne James P. , Foster Michelle T. , Horneman Hart F. , Pecoraro Norman C. , Ginsberg Abigail B. , Akana Susan F. , Dallman Mary F.
Published: June 2007

The common hepatic branch of the vagus nerve is a two‐way highway of communication between the brain and the liver, duodenum, stomach and pancreas that regulates many aspects of food intake and metabolism. In this study, we utilized the afferent‐specific neurotoxin capsaicin to examine if common hepatic vagal sensory afferents regulate lard intake. Rats implanted with a corticosterone pellet were made diabetic using streptozotocin (STZ) and a subset received steady‐state exogenous insulin replacement into the superior mesenteric vein. These were compared with non‐diabetic counterparts. Each group was then subdivided into those whose common hepatic branch of the vagus was treated with vehicle or capsaicin. Five days after surgery, the rats were offered the choice of chow and lard to consume for a further 5 days. The STZ‐diabetic rats ate significantly less lard than the non‐diabetic rats. Capsaicin treatment restored lard intake to that of the insulin‐replaced, STZ‐diabetic rats, but modified neither chow nor total caloric intake. This increased lard intake led to selective fat deposition into the mesenteric white adipose tissue depot, as opposed to an increase in all visceral fat pad depots evident after insulin replacement‐induced lard intake. Capsaicin treatment also increased the levels of circulating glucose and triglycerides and negated the actions of insulin on these and free fatty acids and ketone bodies. Collectively, these data suggest that afferent signalling through the common hepatic branch of the vagus inhibits lard, but not chow, intake, directs fat deposition and regulates plasma metabolite levels.
Phospholipases and fatty acid signalling in exocytosis
Authors: Darios Frédéric , Connell Emma , Davletov Bazbek
Published: June 2007

Vesicle fusion is a ubiquitous biological process involved in general membrane trafficking and a variety of specialized events, for example release of neurotransmitters and hormones, sperm acrosome exocytosis, plasma membrane repair and neurite outgrowth. Many vesicle fusion events have long been known to be activated by phospholipases and products of their activity, such as polyunsaturated arachidonic acid. Polyunsaturated fatty acids (PUFAs) have been proposed to have a number of multiple effectors, including ion channels and the cytoskeleton, but the precise mechanism of PUFA action is still unclear. It was recently reported that omega‐3 and omega‐6 PUFAs can act on syntaxin, a plasma membrane protein directly involved in vesicle fusion. In this review, we will discuss the role of this new mode of PUFA action in exocytosis.
Mechanisms of tonic, graded release: lessons from the vertebrate photoreceptor
Authors: Heidelberger Ruth
Published: June 2007

The release of neurotransmitter via exocytosis is a highly conserved, fundamental feature of nervous system function. At conventional synapses, neurotransmitter release occurs as a brief burst of exocytosis triggered by an action potential. By contrast, at the first synapse of the vertebrate visual pathway, not only is the calcium‐dependent release of neurotransmitter typically graded with respect to the presynaptic membrane potential, but release can be maintained throughout the duration of a sustained stimulus. The specializations that provide for graded and sustained release are not well‐defined. However, recent advances in our understanding of basic synaptic vesicle dynamics and the calcium sensitivity of the release process at these and other central, glutamatergic neurons have shed some light on the photoreceptor's extraordinary abilities.
Prediction of Flash Temperature at the Contact Between Sliding Bodies With Nanoscale Surface Roughness
Authors: Ray Sudipto , Roy Chowdhury S. K.
Published: June 2007

In view of the difficulty in measurement of flash temperature rise at the contact between rough sliding bodies a good deal of work has been carried out in the last few decades to predict flash temperatures theoretically. However, as surfaces become smoother and loading decreases in applications such as MEMS, NEMS and magnetic storage devices measurement of flash temperature becomes increasingly more difficult due to the nanometer scale asperity interactions. Consequently measurement of flash temperature at the nanoscale asperity contact has not yet been possible. The analysis of flash temperature rise under these circumstances is no less challenging since it must consider not only the small-scale asperity height distributions but also the surface forces those may operate at very small surface separations. The paper attempts to predict the flash temperature rise analytically using a fractal approach to describe the nanoscale asperity interactions at low loads and also taking into account the influence of relevant parameters including the surface forces. The important observation here is that in addition to the dependence on load, speed, and material parameters the flash temperature steadily rises with surface adhesion but falls with the fractal dimension D until a critical value of around 1.5, and then rises again. The flash temperature also falls with Fourier number. Under certain combinations of load, speed, and material parameters, extremely high flash temperature is predicted while under certain other parametric combinations extremely low flash temperature may occur. The later parametric combination is certainly of much practical importance.
An Elastohydrodynamic Lubrication Model for Coated Surfaces in Point Contacts
Authors: Liu Yuchuan , Wayne Chen W. , Zhu Dong , Liu Shuangbiao , Wang Q. Jane
Published: June 2007

An elastohydrodynamic lubrication (EHL) model for coated surfaces in point contacts has been developed by combining the elastic deformation formulation for the coated surfaces with an EHL model. Inverse fast Fourier transform (IFFT) is employed first to obtain the influence coefficients (ICs) from the frequency response function (FRF). The subsequent calculation of elastic deformation is performed using the efficient algorithm of discrete convolution and fast Fourier transform (DC-FFT). The coating EHL model is verified by the comparison to available numerical results. The effects of coating on lubrication under various loads, speeds, rheological models, and pressure-viscosity behaviors are numerically investigated. Similar to the observations from dry contact, stiffer coatings in EHL tend to reduce the nominal contact radius but increase the maximum contact pressure, and vice versa for more compliant coatings. However, as coating thickness increases, the influence of coatings on film thickness, including the central and the minimum film thicknesses, does not follow a monotonic variation, and therefore, cannot be predicted by any simple film thickness equation. The reason for that is the pressure viscosity effect which tends to counterbalance the effect of coating. The average friction coefficient in lubricant film increases in stiff coating cases but decreases for compliant coating cases. Furthermore, two possible approaches to improving the minimum film thickness thus reducing friction and wear in mixed lubrication are indicated: a thin stiff coating for conventional EHL and a thick compliant coating for soft EHL.
Air Bearing Slider-Disk Interface for Single-Sided High Speed Recording on a Metal Foil Disk
Authors: White James
Published: June 2007

There are disk-drive data storage applications best served by single-sided recording configurations. These include situations where (i) storage requirements can be achieved on a single side of a disk and (ii) dimensional constraints on the disk drive prohibit the presence of a recording head and its associated mounting device on each side of the disk. Even if dimensional requirements are not a concern, the most cost-effective and operationally efficient slider-disk air-bearing interface for single-sided recording is one that does not include an air-bearing slider, pressure pad, or other air-bearing structure on the nondata side of the disk. A metal foil disk offers some of the best characteristics of both the hard disk and floppy disk for digital data storage. It offers hard disk recording densities, increased shock resistance, reduced manufacturing cost, and requires less operational energy than a hard disk. However, use of a conventional recording head slider assembly without opposing air-bearing support for single-sided recording on a high-speed metal foil disk presents a fundamental problem because the air-bearing surface of the slider produces a net transverse force to the disk. This force causes the disk to deflect and can result in flying height and stability problems at the slider-disk interface. The current work describes an air-bearing interface for low flying height single-sided recording on a high-speed metal foil disk that minimizes disk deflection and instability without the presence of air-bearing components on opposing sides of the disk. The new interface utilizes a vacuum cavity-type air-bearing with little or no preload. Examples will be presented and discussed for the new interface that illustrate the flying characteristics of a picosized slider on a 1.8in. stainless steel disk with thickness of 25.4μm.
Effects of Molecularly Thin Liquid Lubricant Films on Slider Hysteresis Behavior in Hard Disk Drives
Authors: Tagawa Norio , Mori Atsunobu , Senoue Ken
Published: June 2007

In order to achieve a magnetic recording density of 1Tb∕in2, the spacing is expected to be less than 2–3nm. However, a critical issue in achieving such an ultralow spacing is the dynamic instability of the head disk interface (HDI). That is, the experimentally observed hysteresis of fly sliders. The phenomenon of slider hysteresis has two features: slider touchdown and slider takeoff. The goal of this research is to experimentally clarify the effects of the lubricant bonded ratio as well as the lubricant film thickness on slider hysteresis behavior in detail. It also aims to determine the contributing factors. In this study, the difference in the touchdown and takeoff velocities was monitored by varying the lubricant bonded ratio and lubricant film thickness of the disks. Furthermore, the correlation between the observed phenomenon and the variation in the experimental parameters was investigated. The results showed that the touchdown velocities were almost independent of the lubricant bonded ratio, while the takeoff velocities were greater for a lubricant with a higher bonded ratio. These results were obtained for a constant lubricant film thickness of around one monolayer. Therefore, the slider hysteresis was greater for a lubricant with a higher bonded ratio. With regard to the effect of lubricant film thickness, it was observed that the touchdown and takeoff velocities were greater for thinner lubricants. These results for the effect of lubricant film thickness are very similar to those obtained by Ambekar, Gupta, and Bogy (2005, ASME J. Tribol., 127(3), pp. 530–536). However, the slider hysteresis was greater for thicker lubricants. Considering these experimental results as well as the experimental data for the effect of the surface roughness of a disk on the slider hysteresis obtained by (Tani et al. (2006, J. Appl. Phys. , 99(8), pp. 08N104-1–08N104-3), it was suggested that the variation in the touchdown velocity is due to a variation in the intermolecular forces. Furthermore, it was suggested that the variation in the takeoff velocity is caused by a variation in the friction forces between the slider and disk surface. This occurs because the takeoff velocity was greater for a lubricant with a higher bonded ratio or a thinner lubricant, which only has a small fraction of free mobile lubricant. The results predicted by the simulations are consistent with those observed experimentally. In addition, a design guideline for next-generation HDI, with small touchdown and takeoff velocities, resulting in small slider hysteresis, is discussed in detail in this paper.
Numerical Simulation of Surface Roughness Effects in Laminar Lubrication Using the Lattice-Boltzmann Method
Authors: Brenner Gunther , Al-Zoubi Ahmad , Mukinovic Merim , Schwarze Hubert , Swoboda Stefan
Published: June 2007

The effect of surface texture and roughness on shear and pressure forces in tribological applications in the lubrication regime is analyzed by means of lattice-Boltzmann simulations that take the geometry of real surface elements into account. Topographic data on representative surface structures are obtained with high spatial resolution with the application of an optical interference technique. The three-dimensional velocity field past these surfaces is computed for laminar flow of Newtonian fluids in the continuum regime. Subsequently, pressure and shear flow factors are obtained by evaluating the velocity field in accordance with the extended Reynolds equation of Patir and Cheng (1978, ASME J. Tribol., 100, pp. 12–17). The approach allows an efficient determination of the hydrodynamic characteristics of microstructured surfaces in lubrication. Especially, the influence of anisotropy of surface texture on the hydrodynamic load capacity and friction is determined. The numerical method used in the present work is verified for a simplified model configuration, the flow past a channel with sinusoidal walls. The results obtained indicate that full numerical simulations should be used to accurately and efficiently compute the characteristic properties of film flows past rough surfaces and may therefore contribute to a better understanding and prediction of tribological problems.
Nanotribological Characterization and Lubricant Degradation Studies of Metal-Film Magnetic Tapes Using Novel Lubricants
Authors: Bhushan Bharat , Cichomski Michal , Tao Zhenhua , Tran Nang T. , Ethen Todd , Merton Chris , Jewett Richard E.
Published: June 2007

In order to improve the durability of metal-film magnetic tapes, novel lubricants, A20H, X-1P, and X, a modified phosphazene, were deposited on the tapes. The adhesion, friction, and wear of the unlubricated/lubricated tapes were investigated using an atomic force microscope (AFM). The degradation of the lubricants was studied using a mass spectrometer in high vacuum. The durability of various unlubricated/lubricated tapes was compared in ambient and in humid air. The AFM test results show that the A20H lubricated tape exhibited lower adhesion and friction than X-1P and X lubricated tapes. The lubricants were believed to be mainly degraded by tribochemical reaction and mechanical shear in high vacuum. In high humidity air, the various lubricated tapes exhibit higher friction than in ambient air. By comparing the tribological performances of the various lubricated tapes to metal particle (MP) tape, it was found that the lubricated metal-film tapes exhibit lower adhesion, friction, and wear than the MP tape.
Development of an Experimental Device to Study Real Connecting-Rod Bearings Functioning in Severe Conditions
Authors: Michaud Philippe , Fatu Aurelian , Villechaise Bernard
Published: June 2007

The paper presents a new experimental device made to analyze the thermoelastohydrodynamic (TEHD) behavior of connecting-rod bearings functioning in severe conditions. First, it focuses on the test bench description. The general principle of the test bench and then the main original technological solutions used with respect to the functional specifications are detailed. Two numerical models are described. They were developed in order to design and to validate two central components of the experimental device. Finally, the paper comments on the test results used to understand and validate the traction∕compression loading system, which is one of the key points in the test bench behavior.
Effects of Pitch Static Attitude and Roll Static Attitude on the Steady Performance of Air Bearing Sliders
Authors: Zhu Hong , Bogy David B.
Published: June 2007

This paper addresses the effects of pitch static attitude (PSA) and roll static attitude (RSA) on air bearing slider steady performance, especially for ultralow flying height sliders. We performed simulations for three different low flying sliders with flying heights (FHs) of 7nm, 5nm, and 3.5nm using the static simulator code of the Computer Mechanics Laboratory. We found that PSA and RSA have quite significant effects on the steady performance of these air bearing slider designs, and the effect is more important the smaller the size and the lower the FH of the slider. We also investigated the effects of suspension stiffness on the air bearing sliders’ flying attitude (pitch and roll) and found that these effects are similar to those of PSA and RSA.
Single-Atom Single-Photon Quantum Interface
Authors: Wilk Tatjana , Webster Simon C. , Kuhn Axel , Rempe Gerhard
Published: June 2007

A major challenge for a scalable quantum computing architecture is the faithful transfer of information from one node to another. We report on the realization of an atom-photon quantum interface based on an optical cavity, using it to entangle a single atom with a single photon and then to map the quantum state of the atom onto a second single photon. The latter step disentangles the atom from the light and produces an entangled photon pair. Our scheme is intrinsically deterministic and establishes the basic element required to realize a distributed quantum network with individual atoms at rest as quantum memories and single flying photons as quantum messengers.
Manipulated density of adult mallards affects nest survival differently in different landscapes
Authors: Elmberg Johan , Gunnarsson Gunnar
Published: June 2007

Breeding success in many birds including wildfowl is mainly determined by nest predation. Few studies address cues used by predators to find duck nests, and the same is true for spacing patterns that ducks might use to reduce predation. We designed a crossover experiment in agricultural and forested settings to test the assumption that nest predation rate is related to density of adult birds on a lake. We used introduced wing-clipped mallards ( Anas platyrhynchos L., 1758) to increase local pair density and semi-natural nests to assess predation rate. Depredation patterns were analyzed by model fitting in program MARK, using introduction and landscape type as main effects and abundance of avian predators and wild waterbirds as covariates. Depredation was higher at agricultural lakes than at forest lakes. Nest survival decreased with increasing abundance of wild waterfowl, whereas it tended to increase with the abundance of “other waterbirds”. There was a landscape-dependent effect of increased mallard pair density: positive at agricultural lakes and negative at forest lakes. Avian predators found 91% of depredated “known-predator” nests at agricultural lakes and 25% at forest lakes; mammals found 9% at agricultural lakes and 75% at forest lakes. The landscape-dependent density effect may in part be due to different predator communities in these landscape types.
Social and spatial patterns determine the population structure and colonization processes in mouflon
Authors: Darmon G. , Calenge C. , Loison A. , Maillard D. , Jullien J.-M.
Published: June 2007

Although it is widely accepted that populations vary in space and time, defining the spatial scale of population structure relevant for understanding temporal variation or for management and conservation purposes remains a challenge. We studied jointly temporal patterns of social and spatial structures in an introduced population of mouflon ( Ovis gmelini musimon (Schreber, 1782)) to define the temporal stability of these structures and to uncover the history of the colonization process. We expected social organization to remain stable between years, mouflon to stay sedentary, and colonization to have occurred through a diffusion process. We used yearly censuses performed between 1994 and 2004, and collected information in managers’ archives and newspapers reporting the presence of mouflon in different areas since its introduction in 1954 in the Bauges mountains, France. Mouflons were divided into male and nursery groups, whose number (1.88 ± 0.31 for males and 7.54 ± 0.58 for nurseries) and composition (7.05 ± 1.25 individuals in male groups; 13.6 ± 1.41 females, 8.11 ± 0.72 lambs, and 6.51 ± 0.65 males in the nurseries) remained stable over years. The spatial distribution of nursery groups was clustered in five areas, highly correlated between years (p < 0.001), suggesting that the same groups were observed in given areas every year and confirming the sedentary lifestyle of the species. The presence–absence data of the species since its introduction suggested a colonization by diffusion. We discuss the social and spatial structures of the population and the type of colonization process that could have led to this kind of structure.
Strong response to anuran chemical cues by an extreme dietary specialist, the eastern hog-nosed snake (Heterodon platirhinos)
Authors: Cooper, William E. , Secor Stephen
Published: June 2007

Squamate reptiles use the lingual–vomeronasal system to identify food using only chemical cues. In lizards, most of which are dietary generalists that consume a wide variety of arthropods and other small animals, correlated evolution has occurred between addition of plants to the diet and responsiveness to plant chemical cues. In snakes, many of which are dietary specialists, several studies have detected differences in response strength among populations that correspond to the importance of prey types in different geographic locations. In one species of Thamnophis Fitzinger, 1843, such variation in responsiveness has been demonstrated to have a genetic basis. We studied tongue-flicking and biting responses to chemical cues from a range of potential prey types by nine ingestively naive hatchlings of the eastern hog-nosed snake ( Heterodon platirhinos Latreille in Sonnini and Latreille, 1801), which is an extreme toad specialist that less frequently eats other anurans. The snakes responded most strongly to chemical cues from the southern toad ( Bufo terrestris (Bonnaterre, 1789)), as indicated by significantly greater tongue-flick rate. Only two individuals bit in response to chemicals cues, both to the toad cues. Elevated tongue-flick rates were also elicited by chemical cues from the green frog ( Rana clamitans Latreille in Sonnini de Manoncourt and Latreille, 1801), but the mean rate for frog cues was less than for toad cues. Responses to other potential prey types did not differ from those of the control stimuli. Our findings are consistent with those of several other investigators in showing close correspondence between the inclusion and importance of dietary items and the intensity of chemosensory investigation in snakes. Studies of diverse dietary specialists are needed to establish the generality of this relationship in snakes and to demonstrate that diet and chemosensory responses to food cues coevolve.
Photo-dependent population dynamics of Stentor coeruleus and its consumption of Colpidium striatum
Authors: Cadotte M.W. , Jantz S. , Mai D.V.
Published: June 2007

The predatory protozoan Stentor coeruleus Ehrenberg, 1830 is known to show photosensitivity and photodispersion, avoiding regions of high light intensity as an antipredation strategy. This physiological and behavioral response to light likely has demographic consequences. We manipulated light intensity to determine population responses of S. coeruleus and the resulting effects on its prey Colpidium striatum Stokes, 1886. We show that S. coeruleus maintained the highest population density under ambient light levels and low densities under both high and no light treatments. The results from the no light treatment were surprising because little work has been done on possible important behavioral and physiological processes cued by light. These results add power to the use of S. coeruleus as a model predator system to test ecological dynamics and processes associated with predation.
HODGE POLYNOMIALS OF THE MODULI SPACES OF PAIRS
Authors: MUÑOZ VICENTE , ORTEGA DANIEL , VÁZQUEZ-GALLO MARIA-JESÚS
Published: June 2007

Let X be a smooth projective curve of genus g ≥ 2 over the complex numbers. A holomorphic pair on X is a couple (E, ϕ), where E is a holomorphic bundle over X of rank n and degree d, and ϕ ∈ H0(E) is a holomorphic section. In this paper, we determine the Hodge polynomials of the moduli spaces of rank 2 pairs, using the theory of mixed Hodge structures. We also deal with the case in which E has fixed determinant.
SINGULAR CURVES ON A K3 SURFACE AND LINEAR SERIES ON THEIR NORMALIZATIONS
Authors: FLAMINI FLAMINIO , KNUTSEN ANDREAS LEOPOLD , PACIENZA GIANLUCA
Published: June 2007

We study the Brill–Noether theory of the normalizations of singular, irreducible curves on a K3 surface. We introduce a singular Brill–Noether number ρsing and show that if Pic (K3) = ℤ[L], there are no [Formula: see text]'s on the normalizations of irreducible curves in |L|, provided that ρsing < 0. We give examples showing the sharpness of this result. We then focus on the case of hyperelliptic normalizations, and classify linear systems |L| containing irreducible nodal curves with hyperelliptic normalizations, for ρsing < 0, without any assumption on the Picard group.
The Spatial and Segmental Innervation of Somatic Acupoint — A Study of Canine Shen-Shu Point (BL-23)
Authors: Chien Chi-Hsien , Tsai Yu-Chuan , Tseng Chi-Yu , Huang Bu-Miin , Chang Yung-Hsien
Published: June 2007

Although an acupuncture needle penetrates the skin, subcutaneous tissue, and underlying muscle, the most effective locus for the somatic acupoint on the needle path is not well established. We therefore investigated the sensory innervations of tissues in the needle path of the canine Shen-Shu point and evaluated their roles in initiating an acupunctural signal. Horseradish peroxidase solution was injected at all three levels within the acupoint. Only a few peroxidase-positive neurons were observed in the L1 dorsal root ganglion following intradermal injection. Following subcutaneous injection, peroxidase-labeled neurons were detected extending from spinal levels T10 to L2, with maximal labeling at T12 (46.3%). Approximately 95% of positive neurons were at spinal levels T11, T12, T13, and L1. As a result of an intramuscular injection, labeled neurons were observed at spinal levels T12 to L3, with most labeling occurring at L1 (39.9%). Approximately 95% of positive neurons were at spinal levels T13, L1, and L2. The results suggest that most afferent terminals are in the subcutaneous tissue rather than the muscular tissue, with an approximate ratio of 3.75:1. The data provide solid evidence that sensory innervation to a somatic acupoint is confined to a spinal segment and spatially organized, and we speculate that to cause a maximum effect, the centripetally transmitted signal from needling a somatic acupoint is spatio-segmental and divergently amplified.
Anti-Emetic Effect of Oculo-Acupuncture on Dogs with Xylazine Induced Vomiting
Authors: Liu Jianzhu , Lee Yoo-Teak , Lee Sang-Eun , Lee Jung-Yeon , Kim Duck-Hwan
Published: June 2007

The present study was conducted in order to clarify the anti-emetic effect of oculo-acupuncture (OA) on dogs with xylazine-induced vomiting, and also to compare the anti-emetic effect of OA and body acupuncture (AP). Twelve dogs induced to vomit by xylazine were selected from total 29 mongrel dogs in preliminary experiment and were used as subjects in this study. This study was comprised of two experiments. In experiment 1, the anti-emetic effects of OA on dogs were examined in the stomach/spleen region (experimental group I), the zhongjiao region (experimental group II), and the stomach/spleen region plus the zhongjiao region (experimental group III) using 12 dogs induced to vomit for one week interval repeatedly. On the other hand, needle acupuncture (AP) (BL20 + BL21, experimental group A) and OA (stomach/spleen and zhong jiao regions) combined with needle AP (BL20 + BL21) (experimental group B) were examined using 6 vomiting dogs, for one week interval repeatedly in experiment 2. As a result, the vomiting rates of experimental group I (50%, p < 0.05), experimental group II (58.3%) and experimental group III (41.6%, p < 0.01) were lower than that of control (100%), respectively in experiment 1. The vomiting rates of both experimental group A (50%, p < 0.05) and experimental group B (50%, p < 0.05) were lower than that of control (100%) in experiment 2. The starting vomiting time in experimental groups was similar to that of the control groups in experiment 1 and 2. This study demonstrated that OA had anti-emetic effects on dogs with xylazine-induced vomiting and OA in the stomach/spleen region plus the zhongjiao region was the most effective in anti-emesis among the experimental groups. In addition, body AP and OA combined with body AP had a similar anti-emetic effect on dogs with xylazine-induced vomiting.
Electro-Acupuncture of Foot YangMing Regulates Gastric Activity Possibly through Mediation of the Dorsal Vagal Complex
Authors: Wang Jing-Jie , Ming Qin , Liu Xiao-Dong , Huang Yu-Xin , Chen Liang-Wei , Qiu Jian-Yong , Duan Li , Cao Rong , Rao Zhi-Ren
Published: June 2007

Acupuncture at some specific acupoints of Foot Yangming can regulate gastric activity. However, its precise mechanism remains unknown. In our study, the effects and mechanism of electro-acupuncture (EA) at Tsusanli (ST 36), Shangchuhsu (ST 37) on the regulation of gastric activity were observed. EA at Tsusanli showed that gastric electric change had a significantly higher frequency and wave amplitude as compared to that of the Shangchuhsu group and other groups. EA at Shangchuhsu demonstrated the change of gastric electric was greater than that of the non-acupoint group and the control group. After bilateral vagotomy, the change of electro gastric graph (EGG) of EA at Tsusanlis was not significant compared to the control group. In the mean time, we have observed the electric discharge of the neurons in NTS and DMV. The frequency of electro-physiological activity in nucleus of solitary tract (NTS) and dorsal motor nucleus of the vagus nerve (DMV) in Tsusanli group and Shangchuhsu group were markedly increased compared with that in other groups. The results have indicated that EA at Tsusanli and Shangchuhsu not only regulate gastric activity, but also activate neurons in NTS and DMV significantly. Our study suggests that the effect of EA at Tsusanli and Shangchuhsu on the gastric activity may partially depend upon integrated nerve pathway and related central neurons in dorsal vagal complex.
Ligustilide Reduces Phenylephrine Induced-Aortic Tension In Vitro but has No Effect on Systolic Pressure in Spontaneously Hypertensive Rats
Authors: Du Jun-Rong , Yu Yan , Yao Yao , Bai Bo , Zong Xu , Lei Yang , Wang Cheng-Yuan , Qian Zhong-Ming
Published: June 2007

Radix Angelica sinensis, known as Danggui in Chinese, has been used to treat cardiovascular diseases in traditional Chinese medicine for a long time. Experimental evidence showed that the essential oil of Danggui could reduce blood pressure in rabbits, cats or hypertensive dogs when given intravenously. In this study, we investigated the effects of Z-ligustilide, the main lipophilic component of the essential oil of Danggui on aortic tension induced by phenylephrine, an alpha-adrenergic agonist, in vitro and the systolic blood pressure in SHR rats. We demonstrated for the first time that ligustilide can significantly reduce the phenylephrine-induced aortic tension in vitro with IC50 about 64 μg/ml, but has no in vivo effect on systolic blood pressure in SHR rats when administrated orally. The data on transport of ligustilide across Caco-2 monolayer suggested an efficient intestinal absorption of ligustilide in vivo, implying that the non-effectiveness of ligustilide in vivo is not due to the poor absorption in the gastrointestinal tract. Further studies on whether ligustilide is one of the main anti-hypertensive components of the essential oil are needed.
Armillariella melleaShows Anti-inflammatory Activity by Inhibiting the Expression of NO, iNOS, COX-2 and Cytokines in THP-1 Cells
Authors: Wu Shu-Jing , Tsai Jenn-Yi , Lai Min-Nan , Ng Lean-Teik
Published: June 2007

Armillariella mellea (AM), also known as Mi-Huan-Ku, a popular medicinal fungus used in the traditional Chinese medicine for treating headache, neurasthenia and insomnia. In the present study, our aim was to determine the effects of aqueous (AAM) and ethanol (EAM) extracts of A. mellea on lipopolysaccharide (LPS)-induced inflammatory response by measuring the inducible nitric oxide synthase (iNOS), cyclooxygenase-1 and -2 (COX-1 and COX-2) protein expression, cytokines (TNF-α, IL-4 and IL-8) formation, nitric oxide (NO) release and prostaglandin (PGE2) production in human monocytic (THP-1) cells. At concentration of 100 μg/ml, EAM, but not AAM, effectively protected against LPS-induced cell death in THP-1 cells. At concentrations of 10~100 μg/ml, EAM showed a potent anti-inflammatory activity as demonstrated by a dose-dependent inhibition of LPS (1 μg/ml)-induced release of NO and PGE2, and significantly decreased the transcription of proinflammatory cytokines. EAM at 100 μg/ml significantly blocked the LPS induction of iNOS and COX-2 expression, but not COX-1. Therefore, the protective effect of EAM against LPS-induced inflammatory mediators release could explain, at least in part, its effectiveness in alleviating certain inflammatory related diseases.
Mechanism of the Anti-Cancer Activity of Zizyphus jujuba in HepG2 Cells
Authors: Huang Xuedan , Kojima-Yuasa Akiko , Norikura Toshio , Kennedy David Opare , Hasuma Tadayoshi , Matsui-Yuasa Isao
Published: June 2007

The Zizyphus jujuba fruit has been used as a traditional Chinese medicinal herb and considered to affect various physiological functions in the body for thousands of years. However, its anti-cancer activity and mechanism of action remain to be elucidated. We investigated the anti-cancer activity of Zizyphus jujuba Mill and its underlining mechanisms of action in human hepatoma cells (HepG2) and found that the extract of Z. jujuba decreased the viability of the cells. Further extraction of the initial Z. jujuba extract with organic solvents revealed that the chloroform fraction ( CHCl 3-F) was the most effective. Interestingly, the CHCl 3-F induced not only apoptosis but also G1 arrest at a low concentration (100 μg/ml) and G2/M arrest at a higher concentration (200 μg/ml) by cell cycle assay. Apoptosis, an increase in intracellular ROS (reactive oxygen species) level, a decline of mitochondrial membrane potential at low Z. jujuba concentrations, and a ROS-independent mitochondrial dysfunction pathway at high concentrations were all observed. CHCl 3-F-induced G1 arrest in HepG2 cells was associated with an increase in hypohosphorylation of Rb and p27Kip1, and a decrease of phosphorylated Rb . However, CHCl 3-F-induced G2/M arrest in HepG2 cells correlated with a decrease of the p27Kip1 levels and generation of the phosphorylation of p27Kip1, however the hypohosphorylation of Rb protein remained. Collectively, our findings suggest that the CHCl 3-F extract of Z. jujuba extract induced a concentration dependent effect on apoptosis and a differential cell cycle arrest in HepG2 cells.