bluuebunny/crossref_metadata_2025 huggingface dataset:
Dependence of calculus retropulsion on pulse duration during HO: YAG laser lithotripsy
Authors: Kang Hyun Wook , Lee Ho , Teichman Joel M.H. , Oh Junghwan , Kim Jihoon , Welch Ashley J.
Published: July 2006

Background and Objectives

The purpose of this study was to investigate the effect of optical pulse duration on stone retropulsion during Ho:YAG (λ = 2.12 µm) laser lithotripsy.

Study Design/Materials and Methods

A clinical Ho:YAG laser with pulse durations was employed to fragment calculus phantoms and to evaluate stone phantom retropulsion. At a given pulse energy, optical pulse durations were divided into two discrete conditions: short pulse (τp: 120 ∼ 190 µseconds at FWHM) and long pulse (τp: 210 ∼ 350 µseconds at FWHM). Plaster of Paris calculus phantoms were ablated at different energy levels using optical fibers of varying diameters (273, 365, and 550 µm in core size). The dynamics of the recoil action of a calculus phantom was monitored using a high‐speed camera; the laser‐induced craters were evaluated with optical coherent tomography (OCT). Bubble formation and collapse were recorded with a fast flash photography setup, and acoustic transients were measured with a hydrophone.

Results

Shorter pulse durations produced more stone retropulsion than longer pulses at any given pulse energy. Regardless of pulse duration, higher pulse energy and larger fibers resulted in larger ablation volume and retropulsion (P<0.05). For shorter pulse durations, more rapid bubble expansion was observed and higher amplitudes of the collapse pressure wave were measured (P<0.05).

Conclusion

Less retropulsion and equivalent fragmentation occurred when Ho:YAG pulse duration increased. Lasers Surg. Med. 38:762–772, 2006. © 2006 Wiley‐Liss, Inc.
Reaction of Boranes with TMS Diazomethane and Dimethylsulfoxonium Methylide. Synthesis of Poly(methylidene‐co‐TMSmethylidene) Random Copolymers
Authors: Bai Jie , Shea Kenneth J.
Published: July 2006

Summary: Borane reacts with TDM by a sequence of insertion and disproportionation reactions to yield tris‐(trimethylsilylmethyl)borane. No further addition of TDM occurs. Triallylborane and tris‐(4‐methoxyphenylethyl)borane initiate the copolymerization of TDM and dimethylsulfoxonium methylide. The reactions afford TMS‐substituted polymethylene oligomers. The resultant poly(methylidene‐co‐TMSmethylidene) random copolymers arise from incorporation of TMSmethylidene (CHSiMe3) and methylidene (CH2) groups into the growing polymer chain one carbon at a time.

Trialkylborane‐catalyzed copolymerization of trimethylsilyl diazomethane and dimethylsulfoxonium methylide.

magnified image

Trialkylborane‐catalyzed copolymerization of trimethylsilyl diazomethane and dimethylsulfoxonium methylide.
Direct Synthesis of Fully Sulfonated Polyarylenethioether Sulfones as Proton‐Conducting Polymers for Fuel Cells
Authors: Bai Zongwu , Dang Thuy D.
Published: July 2006

Summary: SPTES polymers have been successfully synthesized by direct polymerization using tetramethylene sulfone as the solvent. The chemical structures of the SPTES polymers are confirmed by FT‐IR and NMR spectroscopy. The thermal stability is characterized by TGA, and the results show that the sulfonated groups on the polymer backbone are stable up to 300 °C. The measured proton conductivity reaches values above 300 mS · cm−1 at 65 °C and 85% relative humidity. Tough, ductile, free‐standing membranes have been fabricated by solution casting from N,N‐dimethylacetamide, which indicates that the SPTES polymers have excellent membrane‐forming capability and mechanical property. The mono‐functional monomers are introduced into the polymerization to end‐cap the SPTES polymers. The end‐capping groups are effective in improving water resistance, oxidative stability, and retaining the proton conductivity.

Fully sulfonated polyarylenethioether sulfone.

magnified image

Fully sulfonated polyarylenethioether sulfone.
Mouse oocytes derived from fetal germ cells are competent to support the development of embryos by in vitro fertilization
Authors: Shen Wei , Li Lan , Zhang Donghui , Pan Qingjie , Ding Mingxiao , Deng Hongkui
Published: July 2006

Mouse oocyte development in vitro has been studied in the past several years, but no evidence showed that the fertilizable oocytes could be obtained from the fetal mouse germ cells before the formation of the primordial follicles. In this study, an efficient and simple method has been established to obtain the mature oocytes from the fetal mouse germ cells at 16.5 days post‐coitum (dpc). For the initial of follicular formation, fetal mouse 16.5 dpc ovaries were transplanted to the recipient under the kidney capsule, and the ovaries were recovered after 14 days. Subsequently, the growing preantral follicles in the ovarian grafts were isolated and cultured in vitro for 12 days. Practically, the mature oocytes ovulated from the antral follicles were able to be fertilized in vitro and support the embryonic development. The results demonstrate that the fetal mouse 16.5 dpc germ cells are able to form primordial follicles with the ovarian pregranulosa cells during the period of transplantation in the ectopic site, and the oocytes within the growing follicles are able to mature in vitro, then are able to support the embryonic development. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Analysis of the solid phase stress tensor in multiphase porous media
Authors: G. Gray William , A. Schrefler Bernhard
Published: July 2006

Conservation equations for mass, momentum, energy, and entropy are formulated for the phases and interfaces of a three‐phase system consisting of a solid and two immiscible fluids. The microscale equations are averaged to the macroscale by integration over a representative elementary volume. Thermodynamic statements for each of the phases and interface entities are also formulated at the microscale and then averaged to the macroscale. This departure from most uses of thermodynamics in macroscale analysis ensures consistency between models and parameters at the two scales. The expressions for the macroscale rates of change of internal energy are obtained by differentiating the derived forms for energy and making use of averaging theorems. These thermodynamic expressions, along with the conservation equations, serve as constraints on the entropy inequality. A linearization of the resulting equations is employed to investigate the theoretical origins of the Biot coefficient that relates the hydrostatic part of the total stress tensor to the normal force applied at the solid surface by the pore fluids. The results here are placed in the context of other formulations and expressions that appear in the literature. Copyright © 2006 John Wiley & Sons, Ltd.
Noninvasive monitoring of chest wall movement in infants using laser
Authors: Kondo Tsutomu , Minocchieri Stefan , Baldwin David N , Nelle Mathias , Frey Urs
Published: July 2006

Traditionally, non‐invasive monitoring of tidal volume in infants has been performed using impedance plethysmography analyzed using a one or two compartment model. We developed a new laser system for use in infants, which measures antero–posterior movement of the chest wall during quiet sleep. In 24 unsedated or sedated infants (11 healthy, 13 with respiratory disease), we examined whether the analysis of thoracoabdominal movement based on a three compartment model could more accurately estimate tidal volume in comparison to VT measured at the mouth. Using five laser signals, chest wall movements were measured at the right and left, upper and lower ribcage and the abdomen. Within the tidal volume range from 4.6 to 135.7 ml, a three compartment model showed good short term repeatability and the best agreement with tidal volume measured at mouth (r2 = 0.86) compared to that of a single compartment model (r2 = 0.62, P < 0.0001) and a two compartment model (r2 = 0.82, P < 0.01), particularly in the presence of respiratory disease. Three compartment modeling of a 5 laser thoracoabdominal monitoring permits more accurate estimates of tidal volume in infants and potentially of regional differences of chest wall displacement in future studies. Pediatr Pulmonol. 2006, 41:985–992. © 2006 Wiley‐Liss, Inc.
Dependence of conductance spectra of d ‐wave superconductors on gap suppression near surface
Authors: Pairor P. , Nilmoung S.
Published: July 2006

The effect of gap suppression near the surface on the conductance spectra of normal metal‐d ‐wave superconductor junctions in the tunnelling limit is theoretically studied. The positions of the maxima of the spectra for {100} junctions are found to be not always at the gap maximum of the bulk. Instead, they are at the value of the gap at the interface. For {110} junctions, zero‐bias conductance peaks is absent when the gap function is totally suppressed at the interface. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Critical temperatures in proximity coupled Nb/Pd0.86Ni0.14 bilayers
Authors: Cirillo C. , Aarts J. , Attanasio C.
Published: July 2006

The proximity effect between a superconductor (S) and a weak ferromagnet (F) in sputtered Nb/Pd0.86Ni0.14 bilayers has been studied. The superconducting critical temperature behavior was studied in the framework of a recent theoretical model, in two different approximations, which both give the same final results, allowing to estimate the exchange energy of the ferromagnet and the interface transparency of the S/F barrier. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Method of interlayer tunneling for studies of layered high temperature superconductors and charge density wave materials
Authors: Latyshev Yu. I. , Monceau P. , Brazovskii S. A. , Orlov A. P. , Yamashita T. , Bulaevskii L. N.
Published: July 2006

A brief review of recent results on interlayer tunneling spectroscopy of layered high temperature superconductors (HTS) and charge density wave (CDW) materials is presented demonstrating high capability of this method for studies of both electron condensed states. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Managing Corporate Information Systems Evolution and Maintenance
Authors: Seaman Carolyn B.
Published: July 2006

In 2005 Idea Group Publishing released another volume on issues in software maintenance. This follows their 2003 volume entitled Advances in Software Maintenance Management: Technologies and Solutions, which I also reviewed here (Journal of Software Maintenance and Evolution: Research and Practice 2003; 15(5): 375–377). A variety of readers, with a variety of goals, will find this 2005 book useful. While it is clearly not a textbook, particular chapters could be used in a classroom setting to expose students to current streams of research in software maintenance, as well as to different perspectives on basic maintenance issues. Practitioners will find practical information on particular maintenance problems they might be facing, including the migration of a large legacy system in general (Chapters 5, 13 and 8–11), or to the Web in particular (Chapters 6, 7 and 11), assessment of maintenance and organizational structure (Chapters 3, 4 and 14), and approaches for changing how an organization carries out software development and maintenance (Chapters 2, 12, 13 and 15), as well as on maintenance management (Chapter 1). While some of these chapters provide a level of detail sufficient to allow the reader to apply the techniques and methods described, most are not meant as recipes, or detailed how‐tos of techniques. Instead, the chapters provide the necessary overview, augmented by extensive lists of references. Copyright © 2006 John Wiley & Sons, Ltd.
Properties and applications of quantum dot heterostructures grown by molecular beam epitaxy
Authors: Henini M.
Published: July 2006

One of the main directions of contemporary semiconductor physics is the production and study of structures with a dimension less than two: quantum wires and quantum dots, in order to realize novel devices that make use of low-dimensional confinement effects. One of the promising fabrication methods is to use self-organized three-dimensional (3D) structures, such as 3D coherent islands, which are often formed during the initial stage of heteroepitaxial growth in lattice-mismatched systems. This article is intended to convey the flavour of the subject by focussing on the structural, optical and electronic properties and device applications of self-assembled quantum dots and to give an elementary introduction to some of the essential characteristics.
Brief report: Disposable income, and spending on fast food, alcohol, cigarettes, and gambling by New Zealand secondary school students
Authors: Darling Helen , Reeder Anthony I. , McGee Rob , Williams Sheila
Published: July 2006

We describe self‐reported sources of income and expenditure, and the association between part‐time employment and spending on fast food, alcohol, cigarettes, and gambling for a sample of 3434 New Zealand (NZ) secondary school students (mean age 15.0 years). Disposable income was usually received from parents and guardians, but nearly 40% of students also reported receiving money from part‐time employment. The proportion of students employed increased as socioeconomic rating increased, and was associated with increased purchasing of fast food and alcohol, and increased spending on cigarettes and gambling. Spending by youth has obvious public health implications, particularly when it is concentrated on products that have a negative health impact.
Lack of age‐associated telomere shortening in long‐ and short‐lived species of sea urchins
Authors: Francis Nicola , Gregg Tiffany , Owen Richard , Ebert Thomas , Bodnar Andrea
Published: July 2006

The red sea urchin, Strongylocentrotus franciscanus, can live in excess of 100 years while the sea urchin Lytechinus variegatus has an estimated lifespan of only 3–4 years. In an effort to understand the molecular mechanism underlying the difference in their longevity we characterized telomere biology in these species of sea urchins. Telomerase activity was found throughout early stages of development in L. variegatus and is maintained in adult tissues of L. variegatus and S. franciscanus. Terminal restriction fragment analysis indicated a lack of age‐associated telomere shortening. These data suggest that long‐ and short‐lived sea urchins do not utilize telomerase repression as a mechanism to suppress neoplastic transformation.
Cultural aspects related to the health of Andean women in Latin America: A key issue for progress toward the attainment of the Millennium Development Goals
Authors: Camacho A.V. , Castro M.D. , Kaufman R.
Published: July 2006

International declarations have affirmed that health is a universal right. In order for people to exercise their right to health, their social and cultural contexts need to be acknowledged. However, due to a number of barriers encountered at different levels of society and geographically this right is not yet fully exercised by a considerable number of women in Latin America.

During the last decade progress has been made in the development of public health policies and programs that integrate and recognize the differences in culture that should be considered when addressing indigenous women's health issues.

However, a biomedical health model, which discounts cultural influences, prevails globally over a more integrated approach. This leads to a lack of access and use of quality reproductive health services and care among indigenous people and is one of several important factors contributing to high levels of maternal mortality and poor reproductive health among indigenous women.

It is important to ensure that an intercultural approach is included in health policies, programs and services. An intercultural strategy fosters dialogue and respect among women, men, and decision‐makers and can contribute to the realization of reproductive health rights and improvement of health outcomes.

The debate continues on how to accelerate progress in public policies, health programs and health services. An intercultural approach to assure the health of indigenous women should be a key part of this discussion. Specific efforts are critical for obtaining better health outcomes for indigenous women and other vulnerable populations, if not progress will stagnate in the middle of the 21st century, jeopardizing the attainment of the Millennium Development Goal (MDGs).
The rapid biophysical profile for early intrapartum fetal well‐being assessment
Authors: Tongprasert F. , Jinpala S. , Srisupandit K. , Tongsong T.
Published: July 2006

Objective: To determine the efficacy of the rapid biophysical profile (rBPP), which uses sound‐provoked, ultrasonographically detected fetal movement and amniotic fluid index, for early intrapartum fetal well‐being assessment and prediction of adverse perinatal outcomes.

Methods: Rapid BPP was performed in 330 women admitted to the labor unit of Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, from January 2005 to July 2005. Those who were delivered later than 24 h after the rBPP, or who required emergency cesarean section because of placenta previa, abruptio placentae or prolapsed cord were to be excluded. Perinatal outcomes were prospectively assessed and recorded for subsequent analysis. The predicting accuracy of rBPP was calculated according to poor outcomes, which included fetal distress, low Apgar score, admission to the neonatal intensive care unit and perinatal death.

Results: Among the 330 pregnancies, there were 6 adverse perinatal outcomes (1.8%). The rBPP had a sensitivity of 50.0%, a specificity of 99.07%, a positive predictive value of 50.0%, a negative predictive value of 99.07% and an accuracy of 98.18%.

Conclusion: With its simplicity, low cost and high specificity but its low sensitivity and low negative predictive value, the rBPP may be used as a back‐up test to confirm fetal well‐being during the early intrapartum period in developing countries.
Evaluation of a novel nested PCR for the routine diagnosis of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV)
Authors: Arjona Alvaro , Barquero Nuria , Doménech Ana , Tejerizo German , Collado Victorio M. , Toural Cristina , Martín Daniel , Gomez-Lucia Esperanza
Published: July 2006

Laboratory diagnosis of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) usually involves both viruses, as the clinical signs are similar and coinfection may occur. Serological methods may not represent an accurate diagnosis: maternal antibodies or cross-reactions may give false positive results to FIV, and false negative results may occur in latent FeLV status, or in certain FIV infection stages. A nested polymerase chain reaction (PCR) technique was designed to detect FeLV, FIV and feline endogenous retrovirus simultaneously. The detection of endogenous sequences was considered indicative of successful DNA extraction. The technique was used to diagnose FIV and FeLV in the blood cells of 179 cats. The κ value with the serological data was 0.69 for FeLV and 0.87 for FIV. The joint detection of FeLV and FIV by this novel nested PCR is sensitive, specific, fast and convenient, and its applicability for clinical diagnosis is promising, as the direct evidence of the presence of the virus is more realistic than the indirect data provided by the serological detection.
Worry content across the lifespan: an analysis of 16- to 74-year-old participants in the British National Survey of Psychiatric Morbidity 2000
Authors: LINDESAY JAMES , BAILLON SARAH , BRUGHA TRAOLACH , DENNIS MICHAEL , STEWART ROBERT , ARAYA RICARDO , MELTZER HOWARD
Published: July 2006

Background. Previous studies suggest that worry content and prevalence may vary as a function of age, but evidence is limited.

Method. Cross-sectional national survey of 8580 householders in Great Britain aged between 16 and 74 years. This analysis examined the relationship between age, worry content (relationships/family, financial/housing, work, health, miscellaneous), common mental disorders, and functional limitation, adjusting for other sociodemographic factors.

Results. Overall, the prevalence of worries declined with age. However, with the exception of worry about relationships, the strength of associations between worry types and mental disorder either remained constant or increased in the older age groups. Compared to the 16–24 years reference group, worries about relationships/family, finances/housing and work were lower in the 55–74 years age groups. Financial/housing worries were increased in the 25–44 years group, and health worries were increased in the 25–64 years groups. There were independent associations between all worry items and the categories of mental disorder. All worry types apart from miscellaneous worries were independently associated, positively or negatively, with functional limitation.

Conclusions. Worry content in the general population varies as a function of age, gender, marital status, and educational attainment. All categories of worry are more prevalent in individuals with common mental disorders. The lower prevalence of worries and their stronger association with mental disorder in old age emphasize the clinical significance of these symptoms in this age group.
A theological reading of Hilary's ‘autobiographical’ narrative in De Trinitate I.1–19
Authors: Beckwith Carl
Published: July 2006

Hilary of Poitiers begins his treatise De Trinitate with what appears to be an autobiographical narration of his journey to the Christian faith. Scholars, though taking different approaches to explain this narration, have overlooked its significance for Hilary's treatise. In the following essay, I argue that Book I is a reflection on sources of knowledge about God, the role of faith and reason in theological inquiry, the proper approach to scripture, and the soteriological context of any discussion on the mystery of God. These methodological reflections guide the reader through Hilary's treatise and make Book I crucial to understanding his purpose in De Trinitate.
Divergent electric fields in downward current channels
Authors: Streltsov A. V. , Marklund G. T.
Published: July 2006

The results from a numerical study on the formation and dynamics of the localized, diverging perpendicular electric fields found in the nightside auroral magnetosphere are presented. These fields are frequently observed inside the downward magnetic field‐aligned current (FAC) channels where the electrons flow upward from the ionosphere. The present study focuses on one particular example of the dynamics of such structures that was recorded by the Cluster spacecrafts on 14 January 2001. Simulations show that the localized, divergent electric fields observed by Cluster can be provided by the interactions between downward FACs and the ionosphere. Conditions promoting the formation of these fields include low ionospheric conductivities and solitary downward current channels. Numerical simulations are used to explain the dynamics of the currents and electric fields observed by the Cluster satellites during this event and also show that such electric fields are not normally detected in the upward current channels.
Urban shakemap methodology for Bucharest
Authors: Bartlakowski Julia , Wenzel Friedemann , Radulian Mircea , Ritter Joachim R. R. , Wirth Wolfgang
Published: July 2006

We develop a methodology for a shakemap for the Romanian capital Bucharest that can be rapidly computed and delivered to the public, once real‐time data access is available to a sufficient extent. The methodology, with which the Californian shakemaps are generated, cannot be transferred to Bucharest, due to a missing understanding of the relationship between the geological near‐surface structure and the ground motion amplification. However, a systematic incorporation of previous seismological observations using Fourier Amplitude Spectra of weak and strong ground motion and a recent urban broadband experiment in Bucharest allows us to interpolate computed seismic intensities from 11 sites, where accelerometers measure the actual motion of a specific earthquake to 31 additional locations in the city, so that a reasonably reliable distribution of ground motion in the city can be determined. We demonstrate this methodology using the MW = 6.0 intermediate‐depth earthquake of October 27, 2004.
Gold nanorods grown from HgTe nanoparticles directly on various surfaces
Authors: Shopova S. I. , Blackledge C. W. , Rosenberger A. T. , Materer N. F.
Published: July 2006

Gold nanorods (NRs) are nucleated by HgTe semiconductor nanoparticles. Growth of ∼200×50nm2 NRs directly on various surfaces is achieved by using an intermediary polyelectrolyte layer. X-ray photoelectron spectroscopy confirms the deposition of gold. An increase in the intensity of the Au NR plasmon resonance is observed with optical extinction spectroscopy. This seeding technique, amenable to many different surfaces, suggests a simple synthetic route to composite materials with interesting electronic and optical properties.
Robust, bistable patterning of the dorsal surface of the
Drosophila
embryo
Authors: Umulis David M. , Serpe Mihaela , O’Connor Michael B. , Othmer Hans G.
Published: July 2006

In many developing systems, the fate of a cell is determined by its position in a time-independent spatial distribution of a morphogen. However, during dorsal–ventral patterning in the
Drosophila
embryo, an initial low-level signal refines to a narrow, high-intensity band. This refinement suggests that cells respond to the local transient morphogen distribution that results from interactions between bone morphogenetic proteins (BMPs), their receptors, the BMP-binding proteins Sog and Tsg, the metalloprotease Tld, and a putative, positively regulated component that locally enhances surface binding of BMPs within the region of high signaling. We develop a computational model for dorsal surface patterning and show that, when positive feedback of a cell surface BMP-binding protein is incorporated, bistability in the kinetic interactions transduces the transient BMP distribution into a switch-like spatial distribution of the BMP-bound receptor. We also show that the inclusion of positive feedback leads to the observed contraction of signaling, because cells near the dorsal midline outcompete adjacent lateral cells for limited amounts of BMP. In the model, cells interpret the morphogen distribution by differentiating according to the history of their exposure rather than to a threshold concentration in a static spatial gradient of the morphogen.
Sympatric speciation under incompatibility selection
Authors: Artzy-Randrup Yael , Kondrashov Alexey S.
Published: July 2006

The existing theory of sympatric speciation assumes that a local population splits into two species under one-dimensional disruptive selection, which favors both of the opposite extreme values of a quantitative trait. Here we model sympatric speciation under selection that favors high values of either of the two independently inherited traits, each required to efficiently consume one of the two available resources, but acts, because of a tradeoff, against those possessing high values of both traits. Such two-dimensional incompatibility selection is similar to that involved in allopatric speciation. Using a hypergeometric phenotypic model, we show that incompatibility selection readily leads to sympatric speciation. In contrast to disruptive selection, two distinct modes of sympatric speciation exist under incompatibility selection: under strong tradeoffs both of the new species are specialists, each consuming its own resource, but under moderate tradeoffs speciation may be asymmetric and involve the origin of a specialist and a generalist species. Also, incompatibility selection may lead to irreversible specialization: under strong tradeoffs, the population speciates if it consists mostly of unspecialized individuals, but remains undivided if most of the individuals are specialized to consume one of the resources. Incompatibility selection appears to be more realistic than disruptive selection, implying that incompatibility between individually adaptive alleles or trait states drives both allopatric and sympatric speciation.
Localizing practice effects in dual-task performance
Authors: Sangals Jörg , Wilwer Maria , Sommer Werner
Published: July 2006

Practice effects on dual-task processing are of interest in current research because they may reveal the scope and limits of parallel task processing. Here we used onsets of the lateralized readiness potential (LRP), a time marker for the termination of response selection, to assess processing changes after five consecutive dual-task sessions with three stimulus onset asynchronies (SOAs) and priority on Task 1. Practice reduced reaction times in both tasks and the interference between tasks. As indicated by the LRP, the reduction of dual-task costs can be explained most parsimoniously by a shortening of the temporal demands of central bottleneck stages, without assuming parallel processing. However, the LRP also revealed a hitherto unreported early activation over the parietal scalp after practice in the short SOA condition, possibly indicating the isolation of stimulus–response translation from other central processing stages. In addition, further evidence was obtained from the LRP for a late motoric bottleneck, which is robust against practice.
To stabilize neutrophil polarity, PIP3 and Cdc42 augment RhoA activity at the back as well as signals at the front
Authors: Van Keymeulen Alexandra , Wong Kit , Knight Zachary A. , Govaerts Cedric , Hahn Klaus M. , Shokat Kevan M. , Bourne Henry R.
Published: July 2006

Chemoattractants like f-Met-Leu-Phe (fMLP) induce neutrophils to polarize by triggering divergent signals that promote the formation of protrusive filamentous actin (F-actin; frontness) and RhoA-dependent actomyosin contraction (backness). Frontness locally inhibits backness and vice versa. In neutrophil-like HL60 cells, blocking phosphatidylinositol-3,4,5-tris-phosphate (PIP3) accumulation with selective inhibitors of PIP3 synthesis completely prevents fMLP from activating a PIP3-dependent kinase and Cdc42 but not from stimulating F-actin accumulation. PIP3-deficient cells show reduced fMLP-dependent Rac activity and unstable pseudopods, which is consistent with the established role of PIP3 as a mediator of positive feedback pathways that augment Rac activation at the front. Surprisingly, such cells also show reduced RhoA activation and RhoA-dependent contraction at the trailing edge, leading to the formation of multiple lateral pseudopods. Cdc42 mediates PIP3's positive effect on RhoA activity. Thus, PIP3 and Cdc42 maintain stable polarity with a single front and a single back not only by strengthening pseudopods but also, at longer range, by promoting RhoA-dependent actomyosin contraction at the trailing edge.
High-energy limits of Laplace-type and Dirac-type eigenfunctions and frame flows
Authors: Jakobson Dmitry , Strohmaier Alexander
Published: July 2006

We relate high-energy limits of Laplace-type and Dirac-type operators to frame flows on the corresponding manifolds, and show that the ergodicity of frame flows implies quantum ergodicity in an appropriate sense for those operators. Observables for the corresponding quantum systems are matrix-valued pseudodifferential operators, and therefore the system remains noncommutative in the high-energy limit. We discuss to what extent the space of stationary high-energy states behaves classically.
Dual Actions of Enflurane on Postsynaptic Currents Abolished by the γ-Aminobutyric Acid Type A Receptor β3(N265M) Point Mutation
Authors: Drexler Berthold , Jurd Rachel , Rudolph Uwe , Antkowiak Bernd
Published: July 2006

Background

At concentrations close to 1 minimum alveolar concentration (MAC)-immobility, volatile anesthetics display blocking and prolonging effects on gamma-aminobutyric acid type A receptor-mediated postsynaptic currents. It has been proposed that distinct molecular mechanisms underlie these dual actions. The authors investigated whether the blocking or the prolonging effect of enflurane is altered by a point mutation (N265M) in the beta3 subunit of the gamma-aminobutyric acid type A receptor. Furthermore, the role of the beta3 subunit in producing the depressant actions of enflurane on neocortical neurons was elucidated.

Methods

Spontaneous inhibitory postsynaptic currents were sampled from neocortical neurons in cultured slices derived from wild-type and beta3(N265M) mutant mice. The effects of 0.3 and 0.6 mm enflurane on decay kinetics, peak amplitude, and charge transfer were quantified. Furthermore, the impact of enflurane-induced changes in spontaneous action potential firing was evaluated by extracellular recordings in slices from wild-type and mutant mice.

Results

In slices derived from wild-type mice, enflurane prolonged inhibitory postsynaptic current decays and decreased peak amplitudes. Both effects were almost absent in slices from beta3(N265M) mutant mice. At clinically relevant concentrations between MAC-awake and MAC-immobility, the anesthetic was less effective in depressing spontaneous action potential firing in slices from beta3(N265M) mutant mice compared with wild-type mice.

Conclusion

At concentrations between MAC-awake and MAC-immobility, beta3-containing gamma-aminobutyric acid type A receptors contribute to the depressant actions of enflurane in the neocortex. The beta3(N265M) mutation affects both the prolonging and blocking effects of enflurane on gamma-aminobutyric acid type A receptor-mediated inhibitory postsynaptic currents in neocortical neurons.
Thoracic Epidural Analgesia Augments Ileal Mucosal Capillary Perfusion and Improves Survival in Severe Acute Pancreatitis in Rats
Authors: Freise Hendrik , Lauer Stefan , Anthonsen Soeren , Hlouschek Verena , Minin Evgeny , Fischer Lars G. , Lerch Markus M. , Van Aken Hugo K. , Sielenkämper Andreas W.
Published: July 2006

Background

Acute pancreatitis has been linked to intestinal barrier dysfunction and systemic inflammatory response with high mortality. Thoracic epidural analgesia improves intestinal perfusion. The authors hypothesized that thoracic epidural analgesia influences microcirculation injury, inflammatory response, and outcome of acute pancreatitis in rats.

Methods

Control groups underwent a sham procedure or untreated pancreatitis induced by intraductal taurocholate injection. In the treatment groups, epidural analgesia was commenced immediately or after a 7-h delay. Fifteen hours after injury, the ileal mucosal perfusion was assessed by intravital microscopy. Thereby, the intercapillary area between all perfused capillaries and between continuously perfused capillaries only was used to differentially quantify total and continuous capillary mucosal perfusion. Villus blood flow and serum levels of amylase, lactate, and interleukin 6 were determined, and pancreatic injury was scored histologically. Seven-day survival was recorded in an additional 30 rats undergoing untreated pancreatitis or pancreatitis with epidural analgesia.

Results

In untreated pancreatitis, decreased total capillary perfusion increased the total intercapillary area by 24%. Furthermore, loss of continuous perfusion increased continuous intercapillary area to 228%. After immediate and delayed epidural analgesia, continuous perfusion was restored (P < 0.05). Blood flow decreased 50% in untreated pancreatitis but was preserved by epidural analgesia (P < 0.05). Biochemical and histologic signs of pancreatitis were not affected by epidural analgesia. Lactate and interleukin-6 levels increased in untreated pancreatitis, which was prevented in the treatment groups (P < 0.05). Epidural analgesia increased 7-day survival from 33% to 73% (P < 0.05).

Conclusion

Thoracic epidural analgesia attenuated systemic response and improved survival in severe acute pancreatitis. These effects might be explained by improved mucosal perfusion.
Incidence of Epidural Hematoma, Infection, and Neurologic Injury in Obstetric Patients with Epidural Analgesia/Anesthesia
Authors: Ruppen Wilhelm , Derry Sheena , McQuay Henry , Moore R Andrew
Published: July 2006

Of the 4 million annual births in the United States, 2.4 million involve epidural analgesia. Serious adverse events are rare but are important in young women. Robust estimates for the risk of harm are not available. Data for superficial and deep infections, hematoma, and transient and permanent neurologic injury were obtained from studies reporting adverse events with obstetric epidural analgesia, and incidence presented as individual risk for a woman, number of events per million women, and percentage incidence. A total of 1.37 million women received an epidural for childbirth, reported in 27 articles. Most information (85% of women) was in larger (> 10,000 women) studies published after 1990, with risk estimates as follows: epidural hematoma, 1 in 168,000; deep epidural infection, 1 in 145,000; persistent neurologic injury, 1 in 240,000; and transient neurologic injury, 1 in 6,700. Earlier and smaller studies produced significantly higher risk estimates for transient neurologic injury plus injury of unknown duration.
Sex–specific association of the androgen to oestrogen ratio with adipocytokine levels in older adults: the Rancho Bernardo Study
Authors: Laughlin Gail A. , Barrett‐Connor Elizabeth , May Susanne
Published: July 2006

Objective  Androgens and oestrogens have opposing effects on some adipocyte functions. Thus, the androgen to oestrogen balance may be as important as the individual hormones in determining the biological interaction between endogenous sex hormones and adipocyte‐derived factors such as adiponectin and leptin. We tested this hypothesis by evaluating the sex‐specific, cross–sectional association of sex hormones and androgen to oestrogen ratios with serum adiponectin and leptin in older men and postmenopausal women.

Design  Cross‐sectional.

Participants  A total of 1510 community dwelling men and postmenopausal women aged 50–92 years.

Measurements  Serum leptin, adiponectin and sex hormone levels.

Results  Adiponectin and leptin levels were higher in women than men (P < 0·001). In both sexes, adiponectin concentrations were lower, and leptin levels higher, with increasing BMI and waist girth (all P < 0·001). Although the ratio of total testosterone to total oestradiol was significantly associated with both adipocytokines in both sexes, the strongest and most consistent hormone–adipocytokine associations were observed when the androgen to oestrogen ratio was expressed as total testosterone to bioavailable oestradiol. In linear regressions, the testosterone to bioavailable oestradiol ratio was positively related to adiponectin and inversely related to leptin, with nearly identical standardized β‐coefficients for men and women (all P < 0·001). The strength of the hormone ratio–adipocytokine associations was reduced, but not eliminated, after adjustment for age, adiposity and cardiovascular disease risk factors, including insulin resistance.

Conclusions  The striking similarity of the hormone ratio–adipocytokine associations for men and women, despite wide differences in sex hormone and adipocytokine levels, suggests these results reflect underlying physiological mechanisms common to both sexes.
Subtle interplay of competition and facilitation among small herbivores in coastal grasslands
Authors: STAHL J. , VAN DER GRAAF A. J. , DRENT R. H. , BAKKER J. P.
Published: July 2006

Overlap in habitat use between herbivores can result in facilitative interactions, through enhancement of forage quality, as well as competitive interactions. The latter result from either interference or indirectly from resource depletion.

We investigated competitive and facilitative interactions between wild Barnacle and Brent Geese and European Brown Hares on a salt marsh in the Dutch Wadden Sea. In a multifactorial experimental design, we manipulated biomass and quality of grass swards and determined foraging preferences of the wild herbivores.

We found that both Barnacle and Brent Geese select plots with plants that have a higher nitrogen content. Barnacle Geese avoid plots with high plant biomass.

Hares prefer the combination of high biomass with high plant quality, when geese are absent. However, in the natural situation with geese present, hares select high biomass swards.

Grazing increases the quality of the vegetation within one season. Geese mainly select plots that have been previously grazed by either geese or hares within the same season.

We conclude that indirect competition through forage depletion by large numbers of geese in spring plays a significant role determining the foraging choices of hares, while Barnacle Geese profit from grazing facilitation by other small herbivores which prevents the maturation of forage tissues.
Physical environmental stimuli that turn healthcare facilities into healing environments through psychologically mediated effects: systematic review
Authors: Dijkstra Karin , Pieterse Marcel , Pruyn Ad
Published: July 2006

Aim.  This paper reports a systematic review to determine the effects of physical environmental stimuli in healthcare settings on the health and well‐being of patients.

Background.  The concept of healing environments suggests that the physical environment of the healthcare setting can encourage the healing process and patients’ feelings of well‐being. Understanding the effects of physical environmental stimuli will allow us to design healthcare environments that generate these potential health benefits.

Method.  A search was conducted using the MedLine, PsychInfo, Embase, CINAHL, Iconda, ScienceDirect, Compendex and the ISI Citation Indexes databases. Studies were included if they concerned interventions involving health effects of environmental stimuli in healthcare settings on patients, and were based on controlled clinical trials published in peer‐reviewed journals. Both clinical and psychological outcome measures were included. The search was completed in 2005.

Findings.  Of the over 500 potentially relevant studies identified, only 30 met all criteria and were included in this review. Predominantly positive effects were found for sunlight, windows, odour and seating arrangements. Inconsistent effects were found for sound, nature, spatial layout, television and multiple stimuli interventions. In general, both the size and direction of effects seem highly dependent on characteristics of patient populations and healthcare settings.

Conclusions.  Studies that manipulate several environmental stimuli simultaneously clearly support the general notion that the physical healthcare environment affects the well‐being of patients. However, when scrutinizing the effects of specific environmental stimuli, conclusive evidence is still very limited and difficult to generalize. The field thus appears to be in urgent need of well‐conducted, controlled clinical trials. At present, and on the basis of the available research, it would be premature to formulate evidence‐based guidelines for designing healthcare environments.
Psychological approaches for the nursing management of chronic pain: part 2
Authors: Richardson Clifford , Adams Nicola , Poole Helen
Published: July 2006

Aims and objectives.  The aim of this article was to present the ways that nurses can integrate psychological approaches into their management of chronic pain conditions using a biopsychosocial framework. Communication, the importance of the patient–practitioner interaction, the role of education and provision of information, reassurance and reduction of anxiety and the use of coping strategies training in the management of chronic pain are reviewed alongside the key skills of nursing.

Background.  This is the second part of a two‐part article. Part 1 was a discussion of psychosocial factors associated with chronic pain conditions and the psychological approaches used in the management of these conditions.

Conclusions.  It is identified that key nursing skills often equate to the requirements of the psychological approaches, therefore specific techniques from a cognitive‐behavioural framework can be readily applied, integrated and used by nurses in the management of chronic pain conditions.

Relevance to clinical practice.  Commonly utilized nursing skills are similar to those required for cognitive‐behavioural therapy. It is reasonable to assume therefore that nurses can and should be involved in effectively managing the psychological aspects associated with chronic pain conditions.
A comparison between integrating clinical practice setting and randomized controlled trial setting into economic evaluation models of therapeutics
Authors: Farahani Pendar , Levine Mitchell , Goeree Ron
Published: July 2006

Background  Cost‐effectiveness analyses generated from randomized controlled trials (RCTs) represent results obtained under ideal experimental conditions (efficacy) and the applicability of these data to real‐world settings (effectiveness) may be questionable.

Objective  To compare cost‐effectiveness results obtained from a RCT setting with the results derived from community‐based clinical practice.

Methods  Using data from a community‐based cohort study and from a RCT, two cost‐effectiveness analyses were performed and the incremental cost‐effectiveness ratios (ICERs) were calculated for the use of etanercept in the treatment of patients with rheumatoid arthritis.

Results  Using an effectiveness‐based analysis, the mean quality‐adjusted life years (QALYs) gained during the 12‐month monitoring period were 0.45 and 0.35 for the treatment and control groups respectively. The ICER for etanercept treatment was $174 200 (CDN) per QALY (95% confidence limits between $119 500 and $285 000). Incorporating efficacy data obtained from the RCT into the analysis, the mean QALYs gained were 0.56 and 0.35 for the treatment and control groups respectively. This resulted in a substantially lower ICER for etanercept treatment of $82 952 per QALY (95% confidence limits between $66 500 and $103 430).

Conclusion  Depending on the type of clinical setting used for the analysis, the resulting ICER for etanercept treatment was very different. These results help to explain the difference in cost‐effectiveness reported in previous modeling studies, some based on RCT assumptions and some based on effectiveness setting.