bluuebunny/crossref_metadata_2025 huggingface dataset:
Turbulent resistivity in wavy two-dimensional magnetohydrodynamic turbulence
Authors: KEATING SHANE R. , DIAMOND P. H.
Published: January 2008

The theory of turbulent resistivity in ‘wavy’ magnetohydrodynamic turbulence in two dimensions is presented. The goal is to explore the theory of quenching of turbulent resistivity in a regime for which the mean field theory can be rigorously constructed at large magnetic Reynolds numberRm. This is achieved by extending the simple two-dimensional problem to include body forces, such as buoyancy or the Coriolis force, which convert large-scale eddies into weakly interacting dispersive waves. The turbulence-driven spatial flux of magnetic potential is calculated to fourth order in wave slope – the same order to which one usually works in wave kinetics. However, spatial transport, rather than spectral transfer, is the object here. Remarkably, adding an additional restoring force to the already tightly constrained system of highRmmagnetohydrodynamic turbulence in two dimensions can actually increase the turbulent resistivity, by admitting a spatial flux of magnetic potential which is not quenched at largeRm, although it is restricted by the conditions of applicability of weak turbulence theory. The absence ofRm-dependent quenching in this wave-interaction-driven flux is a consequence of the presence of irreversibility due to resonant nonlinear three-wave interactions, which are independent of collisional resistivity. The broader implications of this result for the theory of mean field electrodynamics are discussed.
VICTORIANS LIVE
Authors: Sussman Herbert
Published: January 2008

Victorians Liveexamines the afterlife of the Victorians, the ways that Victorian literature and culture remain alive, continue to live in our own day.

“‘Modern Life’ – with a Vengeance”: William Powell Frith at the Guildhall Art Gallery

TIMOTHY BARRINGER

Birth of the Bestseller

HERBERT SUSSMAN
Are Trauma Memories Disjointed from other Autobiographical Memories in Posttraumatic Stress Disorder? An Experimental Investigation
Authors: Kleim Birgit , Wallott Franziska , Ehlers Anke
Published: January 2008

This study tested the hypothesis that trauma memories are disjointed from other autobiographical material in posttraumatic stress disorder (PTSD). Assault survivors with (n = 25) and without PTSD (n = 49) completed an autobiographical memory retrieval task during script-driven imagery of (a) the assault and (b) an unrelated negative event. When listening to a taped imagery script of the worst moment of their assault, survivors with PTSD took longer to retrieve unrelated non-traumatic autobiographical information than those without PTSD, but not when listening to a taped script of the worst moment of another negative life event. The groups also did not differ in general retrieval latencies, neither at baseline nor after the imagery tasks. The findings are in line with suggestions that traumatic memories are less integrated with other autobiographical information in trauma survivors with PTSD than in those without PTSD.
LINKING POETRY, PAINTING, AND PRINTS: THE MODE OF POETIC PICTURES IN LATE MING ILLUSTRATIONS TO THE STORY OF THE WESTERN WING
Authors: Ma Meng-Ching
Published: January 2008

This paper explores a specific mode of illustrations to accompany the most popular dramatic publication in late Ming, The Story of the Western Wing. The visual interpretations of the play will be discussed side by side with the commentaries attributed to contemporary eminent literary figures, in order to examine the common change in reading mentality. Analysis of the image–text relationship for each of the pictures in those editions under discussion reveals that they all relate to the script with the caption taken from the text. Unlike the previous illustrated editions in a narrative mode, the pictures represent the fragmented poetic sentences instead of the narrative text of the play. The caption, a fragmented segment of the text, therefore becomes the key element that relates the image to the text. For the illustrator, it was probably more important to find a key line and a matching scene from the visual repertoire than it was to expound the essence of the script. The emerging mode of “poetic pictures” not only emphasized the poetic quality of the text, but also incorporated visual elements learned from traditional brush painting. The sophisticated integration of poetry and painting into the comparatively popular form of prints attested to the publishers' pursuit of artistic prestige, and the shift in illustrations for narratives during this period.
TAIWANESE STUDIES OF TRADE CERAMICS: AT THE INTERSECTION OF INDIGENOUS AND INTERNATIONAL HISTORIOGRAPHY
Authors: Sakai Takashi
Published: January 2008

Hsieh Ming-liang. Maoyi taoci yu wenhuashi 貿易陶瓷與文化史 (Trade Ceramics and Cultural History). Taipei: Yunchen Wenhua, 2005. Pp. 399 + 9 colour plates.
Earthquake‐generated tsunamis in the Mediterranean Sea: Scenarios of potential threats to Southern Italy
Authors: Lorito Stefano , Tiberti Mara Monica , Basili Roberto , Piatanesi Alessio , Valensise Gianluca
Published: January 2008

We calculated the impact on Southern Italy of a large set of tsunamis resulting from earthquakes generated by major fault zones of the Mediterranean Sea. Our approach merges updated knowledge on the regional tectonic setting and scenario‐like calculations of expected tsunami impact. We selected three potential source zones located at short, intermediate and large distance from our target coastlines: the Southern Tyrrhenian thrust belt; the Tell‐Atlas thrust belt; and the western Hellenic Arc. For each zone we determined a Maximum Credible Earthquake and described the geometry, kinematics and size of its associated Typical Fault. We then let the Typical Fault float along strike of its parent source zone and simulated all tsunamis it could trigger. Simulations are based on the solution of the nonlinear shallow water equations through a finite difference technique. For each run we calculated the wavefields at desired simulation times and the maximum water elevation field, then produced traveltime maps and maximum wave‐height profiles along the target coastlines. The results show a highly variable impact for tsunamis generated by the different source zones. For example, a large Hellenic Arc earthquake will produce a much higher tsunami wave (up to 5 m) than those of the other two source zones (up to 1.5 m). This implies that tsunami scenarios for Mediterranean Sea countries must necessarily be computed at the scale of the entire basin. Our work represents a pilot study for constructing a basin‐wide tsunami scenario database to be used for tsunami hazard assessment and early warning.
The variance of mean sea‐ice thickness: Effect of long‐range dependence
Authors: Percival D. B. , Rothrock D. A. , Thorndike A. S. , Gneiting T.
Published: January 2008

Measured sea‐ice draft exhibits variations on all scales. We regard draft profiles up to several hundred kilometers in length as being drawn from a stationary stochastic process. We focus on the estimation of the mean draftof the process. This elementary statistic is typically computed from a profile segment of lengthLand has some uncertainty, or sampling error, that is quantified by its varianceσL2. How efficiently can the variance ofbe reduced by the use of more data, that is, by increasingL? Three properties of the data indicate the need for a non‐standard statistical model: the varianceσ2Loffalls off more slowly thanL−1; the autocorrelation sequence does not fall rapidly to zero; and the spectrum does not flatten off with decreasing wave number. These indicate that ice draft exhibits, as a fundamental geometric property, ‘long‐range dependence.’ One good model for this dependence is a fractionally differenced process, whose varianceσL2is proportional toL−1+2δ. From submarine ice draft data in the Arctic Ocean, we findδ= 0.27. Mean draft estimated from a 50‐km sample has a sample standard deviation of 0.29 m; for 200 km, it is 0.21 m. Tabulated values provide the sample standard deviationσLfor various values ofLfor samples both in a straight line and in a rosette or spoke pattern, allowing for the efficient design of observational programs to measure draft to a desired accuracy.
Modeling M(3000)F2 based on empirical orthogonal function analysis method
Authors: Liu Chunxu , Zhang Man‐Lian , Wan Weixing , Liu Libo , Ning Baiqi
Published: January 2008

An empirical orthogonal function (EOF) analysis, combined with a regression analysis, is conducted to construct an empirical model for the ionospheric propagation factor M(3000)F2. First, a single station model is constructed using monthly median hourly values of M(3000)F2 data observed at Wuhan Ionospheric Observatory (geographic 114.4°E, 30.6°N; 45.2°dip) during the years of 1957–1991 for demonstrating the modeling technique based on EOF expansion and regression analysis of the EOF coefficients. The constructed climatological model incorporates the diurnal, seasonal as well as solar‐cycle variations of M(3000)F2. A comparison between the observational results and the modeled ones showed good agreement. Then, an attempt is made to model global M(3000)F2 data using data from stations distributed around the world. Our preliminary result showed that the modeling technique based on EOF expansion, which is combined with regression analysis of the EOF coefficients as described in this paper, is very promising when used in global modeling and is worthwhile to investigate further.
Cognitive deficits of schizophrenia: the flower workshop initiative
Authors: Ornellas Pereira Maria Alice , Pereira Alfredo
Published: January 2008

Advancement of research on the neurobiology of the schizophrenic brain has revealed a complex of factors, from genetic tendencies affecting the development of brain structure to functional impairment caused by defective molecular signaling. Recently, the attention of psychiatrists and mental health professionals has been directed to the presence of cognitive deficits, responsible for most of the obstacles to the social insertion of patients.The schizophrenic person has a difficulty to manage the flux of consciousness in social interactions. We address this difficulty with the Flower Arrangement Workshop, a methodology of Psycho-Social Rehabilitation that reduces the vulnerability of the schizophrenic in the social environment. The workshop was offered regularly (18 months) for a group containing 4 schizophrenic subjects.
Novel function of complement C3d as an autologous helper T‐cell target
Authors: Knopf Paul M , Rivera Daniel S , Hai Si‐Han , McMurry Julie , Martin William , De Groot Anne S
Published: January 2008

The C3d fragment of complement component C3 has been shown to enhance immune responses to antigens that lack T‐cell epitopes such as bacterial polysaccharides. C3d binds to the B‐cell complement receptor 2 (CR2 or CD21); this binding serves as a co‐activation signal to the B cell when the polysaccharide antigen portion binds simultaneously to the B‐cell receptor (surface Ig). Bringing together receptor‐associated signal transduction molecules CD19 and Igα/β, respectively, results in a lower threshold of activation. Paradoxically, C3d has also been shown to enhance antibody titers in the CD21 knockout (KO) mouse model as well as increase Th1 and Th2 cytokine secretion, suggesting that that an auxiliary CR2‐independent pathway of immune activation may exist. We hypothesized that in addition to its molecular adjuvant property that enhances signal 1 during B‐cell activation (co‐signal 1), C3d also contains T‐cell epitopes that are able to stimulate autoreactive C3d peptide‐specific helper T cells which we term ‘co‐signal 2’. Using the EpiMatrix T‐cell epitope‐mapping algorithm, we identified 11 putative T‐cell epitopes in C3d, a very high epitope density for a 302 amino‐acid sequence. Eight of these epitope candidates were synthesized and shown to bind a variety of class II HLA‐DR molecules of different haplotypes, and to stimulate C3d peptide‐specific T cells to secrete pro‐inflammatory cytokines in vitro. Further, we demonstrate a C3d‐peptide specific increase in CD4+ intracellular IFN‐γ+ T cells in peripheral blood mononuclear cells (PBMCs) exposed to C3d peptides in vitro. We believe that the discovery of these autologous T cells autoreactive for C3d provides evidence supporting the ‘co‐signal 2’ hypothesis and may offer a novel explanation of the CD21 KO paradox.
Evolution in miniature: selection, survival and distribution of antigen reactive cells in the germinal centre
Authors: Tarlinton David M
Published: January 2008

Productive immune responses to T‐cell‐dependent antigens ultimately generate two long‐lived compartments: memory B cells and bone marrow‐resident plasma cells, which both arise from within germinal centres. The ability of a B‐cell clone to populate these effector compartments requires its descendents to outcompete those of other clones participating in the response. Selection occurs at several stages of the response and the criteria differ at these different stages. While affinity predominates as the key, underlying driving force of selection, there is a distinction made at the point at which germinal centre cells initiate entry into the plasma cell and memory B‐cell compartments. Becoming a plasma cell requires high affinity and cannot be subverted by blocking cell death, while becoming a memory B cell is dependent on survival alone. While such survival is typically mediated by affinity within the GC, the distinction has important mechanistic implications.
Vaccination against self to prevent autoimmune disease: the type 1 diabetes model
Authors: Harrison Leonard C
Published: January 2008

Immune tolerance to self‐antigens is physiological. Given a repertoire of self‐reactive, potentially pathogenic lymphocytes, therapeutic options to diminish autoimmune disease risk include deletion, reduced activation or increased regulation of self‐reactive lymphocytes by means that mimic or promote physiological mechanisms of immunity. Vaccination with self‐antigen to promote self‐antigen‐specific tolerance, ‘negative vaccination’, may represent the most specific and potentially safest means of averting autoimmune disease. This strategy is therapeutically effective in inbred rodent models but its translation in humans has failed to meet expectations. This failure can be attributed to the use of suboptimal dosage regimens in end‐stage disease, as well as other factors. This review focuses on vaccination against self‐antigen in type 1 diabetes, an autoimmune disease unique in that individuals at risk can be identified years before clinical presentation. Moreover, the spontaneously diabetic non‐obese diabetic mouse, which mimics human type 1 diabetes in many ways, has provided ‘proof‐of‐concept’ for negative vaccination. Recent trials of a nasal insulin vaccine in humans at risk of type 1 diabetes provide evidence of tolerance induction as a basis for clinical efficacy.
Interferon type I responses in primary and secondary infections
Authors: Alsharifi Mohammed , Müllbacher Arno , Regner Matthias
Published: January 2008

The mammalian host responds to a microbial infection with a rapid innate immune reaction that is dominated by type I interferon (IFN‐I) release. Most cells of vertebrates can respond to microbial attack with IFN‐I production, but the cell type responsible for most of the systemic IFN‐I release is thought to be plasmacytoid dendritic cells (pDCs). Besides its anti‐microbial and especially anti‐viral properties IFN‐I also exerts a regulatory role on many facets of the sequential adaptive immune response. One of these is being the recently described partial, systemic activation of the vast majority of B and T lymphocytes in mice, irrespective of antigen reactivity. The biological significance of this partial activation of lymphocytes is at present speculative. Secondary infections occurring within a short time span of a primary infection fail to elicit a similar lymphocyte activation response due to a refractory period in systemic IFN‐I production. This period of exhaustion in IFN‐I responses is associated with an increased susceptibility of the host to secondary infections. The latter correlates with well‐established clinical observations of heightened susceptibility of patients to secondary microbial infections after viral episodes.
Development of the cyclic cluster model formalism for Kohn-Sham auxiliary density functional theory methods
Authors: Janetzko Florian , Köster Andreas M. , Salahub Dennis R.
Published: January 2008

The development of the cyclic cluster model (CCM) formalism for Kohn-Sham auxiliary density functional theory (KS-ADFT) methods is presented. The CCM is a direct space approach for the calculation of perfect and defective systems under periodic boundary conditions. Translational symmetry is introduced in the CCM by integral weighting. A consistent weighting scheme for all two-center and three-center interactions appearing in the KS-ADFT method is presented. For the first time, an approach for the numerical integration of the exchange-correlation potential within the cyclic cluster formalism is derived. The presented KS-ADFT CCM implementation was applied to covalent periodic systems. The results of cyclic and molecular cluster model (MCM) calculations for trans-polyacetylene, graphene, and diamond are discussed as examples for systems periodic in one, two, and three dimensions, respectively. All structures were optimized. It is shown that the CCM results represent the results of MCM calculations in the limit of infinite molecular clusters. By analyzing the electronic structure, we demonstrate that the symmetry of the corresponding periodic systems is retained in CCM calculations. The obtained geometric and electronic structures are compared with available data from the literature.
Investigation of oxygen growth pressure effects on TiO2−δ:Co
Authors: Hu E. , von Molnár S. , Stampe P. A. , Kennedy R. J. , Xin Y.
Published: January 2008

We find that depending on the oxygen pressure during growth (PO2), the TiO2−δ:Co films show dramatically different magnetic behaviors. The magnetic properties are dominated by cobalt nanoparticles and are sensitive to the nanoparticle size. Hopping transport behavior expected in multiphase granular metal systems is observed for most of the samples in the measured temperature range and the linear I-V regime. Concomitantly, voltage induced tunneling conduction is observed in high electrical fields (nonlinear I-V regime) and at very low temperature (0.35K). Cross sectional transmission electron microscopy images provide further corroboration of the multiphase structure of these materials.
Pyroelectricity in polyvinylidene fluoride: Influence of polarization and charge
Authors: Fedosov S. N. , von Seggern H.
Published: January 2008

Fractional thermally stimulated depolarization (TSD) currents and temperature-dependent pyroelectricity are experimentally studied in polyvinylidene fluoride samples poled at high direct current field at room temperature. It is demonstrated by a detailed charge balance that the generally assumed proportionality between pyrocoefficients and residual polarization cannot be observed in the low temperature range where polarization irreversibly decreases during heating, while the pyrocoefficient remains constant up to about 60 °C. It is assumed that a portion of the residual polarization results from alignment of the dipoles in the amorphous phase of the polymer. This portion is not related to pyroelectricity and irreversibly vanishes during heating. For lack of screening charges at the crystallite boundaries, an irreversible back switching of the polarization occurs at temperatures higher than 80 °C. Since the relaxation of the compensating charges and that of the ferroelectric polarization are interrelated, it is not possible to distinguish between contributions from polarization and compensation charge to the measured TSD current and to decide which component is thermally more stable. All TSD current cycles show almost the same activation energy of 2.7±0.3 eV. The total released charge during the fractional TSD current experiments amounts to about 30–40% of the residual polarization, indicating that the TSD current due to charge motion partly compensates the depolarization current caused by the dipole realignment. Therefore, the integral of the measured TSD current is always smaller than the corresponding decrement of the residual polarization.
Optimization of synchronization in complex clustered networks
Authors: Huang Liang , Lai Ying-Cheng , Gatenby Robert A.
Published: January 2008

There has been mounting evidence that many types of biological or technological networks possess a clustered structure. As many system functions depend on synchronization, it is important to investigate the synchronizability of complex clustered networks. Here we focus on one fundamental question: Under what condition can the network synchronizability be optimized? In particular, since the two basic parameters characterizing a complex clustered network are the probabilities of intercluster and intracluster connections, we investigate, in the corresponding two-dimensional parameter plane, regions where the network can be best synchronized. Our study yields a quite surprising finding: a complex clustered network is most synchronizable when the two probabilities match each other approximately. Mismatch, for instance caused by an overwhelming increase in the number of intracluster links, can counterintuitively suppress or even destroy synchronization, even though such an increase tends to reduce the average network distance. This phenomenon provides possible principles for optimal synchronization on complex clustered networks. We provide extensive numerical evidence and an analytic theory to establish the generality of this phenomenon.
General analytical solution for photoacoustic effect with multilayers
Authors: Hu Hanping , Zhang Wei , Xu Jun , Dong Yi
Published: January 2008

A general solution of the photoacoustic (PA) effect with multilayers is derived by using a fully thermally-mechanically coupled PA model. This expression takes thermal, mechanical, optical, and geometry properties of multilayers, as well as the thermal contact resistances between layers into consideration. The PA frequency is extended to the ultrasonic region. Therefore, the PA effect at high frequency and laser induced ultrasonic wave in multilayers can also be studied.
Electric field distribution in GaN∕AlGaN∕GaN heterostructures with two-dimensional electron and hole gas
Authors: Buchheim C. , Goldhahn R. , Gobsch G. , Tonisch K. , Cimalla V. , Niebelschütz F. , Ambacher O.
Published: January 2008

Ga-face GaN∕AlGaN∕GaN heterostructures with different cap thicknesses are investigated by electroreflectance spectroscopy (ER). The voltage dependent electric field strengths of the barrier and cap layers are determined. The AlGaN electric field amounts of up to −2.6MV∕cm, whereas the GaN electric field is always below 700kV∕cm. The two electric fields have opposite signs. Characteristic features in the voltage maps of the ER spectra are assigned to the formation/depletion of a two-dimensional electron gas below and a two-dimensional hole gas above the AlGaN barrier. Between −6.5 and 0V, both carrier gases coexist.
Light emission due to dislocations in wurtzite ZnO bulk single crystals freshly introduced by plastic deformation
Authors: Ohno Y. , Koizumi H. , Taishi T. , Yonenaga I. , Fujii K. , Goto H. , Yao T.
Published: January 2008

An arbitrary number of dislocations were freshly introduced in wurtzite ZnO bulk single crystals by plastic deformation at high temperatures (923–1123K), and the optical properties were examined by photoluminescence spectroscopy. ZnO, including a high density (more than 109cm−2) of dislocations, showed excitonic light emission with photon energies of 3.100 and 3.345eV, as well as their LO-phonon replicas, at a temperature of 11K, and the intensities increased with increasing dislocation density.
Independently addressable fields of porous anodic alumina embedded in SiO2 on Si
Authors: Franklin Aaron D. , Janes David B. , Claussen Jonathan C. , Fisher Timothy S. , Sands Timothy D.
Published: January 2008

Fields of thin-film porous anodic alumina (PAA) are fabricated within a SiO2 support and on independently addressable underlying metal pads. The underlying metallization provides a means for unique postprocessing to be performed on the PAA fields. Customized postprocessing is demonstrated with the synthesis of single-walled carbon nanotubes (SWCNTs) from an embedded catalyst in the PAA, followed by selective decoration of the SWCNTs from different PAA fields with dissimilar nanoparticles. Achieving uniquely functionalized fields of PAA on a single chip provides a scalable integration platform to be used in multiplexed chemical and biological sensing or nanoelectronic devices.
Fabrication and transport properties of ZnO∕Nb-1wt%-doped SrTiO3 epitaxial heterojunctions
Authors: Wu Yunlong , Zhang Liuwan , Xie Guanlin , Zhu Jia-Lin , Chen Yonghai
Published: January 2008

(110) ZnO/(001) Nb-1wt%-doped SrTiO3 n-n type heteroepitaxial junctions were fabricated using the pulse laser deposition method. A diodelike current behavior was observed. Different from conventional p-n junctions or Schottky diodes, the diffusion voltage was found to increase with temperature. At all temperatures, the forward current was perfectly fitted on the thermionic emission model. The band bending at the interface can qualitatively explain our results, and the extracted high ideality factor at low temperatures, as well as large saturation currents, is ascribed to the deep-level-assisted tunneling current through the junction.
Blue light emitting diodes grown on freestanding (11-20) a-plane GaN substrates
Authors: Liu J. P. , Limb J. B. , Ryou J.-H. , Yoo D. , Horne C. A. , Dupuis R. D. , Wu Z. H. , Fischer A. M. , Ponce F. A. , Hanser A. D. , Liu L. , Preble E. A. , Evans K. R.
Published: January 2008

Visible blue light emitting diodes have been produced on freestanding nonpolar GaN (11-20) a-plane substrates by metal-organic chemical vapor deposition. The growth conditions have been optimized for smooth growth morphology of GaN nonpolar homoepitaxial layers without surface features, leading to light emitting diode epitaxial structures that are free of crystalline defects such as threading dislocations and stacking faults. Electroluminescence of light emitting diodes exhibit peak wavelengths of ∼450nm and are independent of current level at low current densities before the heating effects are evidenced.
Silicon-based nanochannel glucose sensor
Authors: Wang Xihua , Chen Yu , Gibney Katherine A. , Erramilli Shyamsunder , Mohanty Pritiraj
Published: January 2008

Silicon nanochannel biological field effect transistors have been developed for glucose detection. The device is nanofabricated from a silicon-on-insulator wafer with a top-down approach and surface functionalized with glucose oxidase. The differential conductance of silicon nanowires, tuned with source-drain bias voltage, is demonstrated to be sensitive to the biocatalyzed oxidation of glucose. The glucose biosensor response is linear in the 0.5–8mM concentration range with 3–5min response time. This silicon nanochannel-based glucose biosensor technology offers the possibility of high density, high quality glucose biosensor integration with silicon-based circuitry.
Pull-in instability of parallel-plate electrostatic microactuators under a combined variable charge and voltage configuration
Authors: Son C. , Ziaie B.
Published: January 2008

In this letter, we present a theoretical analysis of pull-in instability of parallel-plate electrostatic microactuators under a combined variable charge and voltage configuration. This occurs in parallel plate capacitors partially filled with a charged dielectric (electret) where the plates are connected together through an impedance. Our results demonstrate the possibility of achieving full range motion under certain conditions. For Teflon® electrets much thinner than the air gap; the maximum traveling distance is similar to the voltage controlled electrostatic actuators (gap/3), whereas for electrets four times thicker than the initial gap the maximum traveling distance can approach 100% of the gap.
The Anti‐Hepatitis B Virus Activity of Boehmeria nivea Extract in HBV‐Viremia SCID Mice
Authors: Chang Jia-Ming , Huang Kai-Ling , Yuan Thomas Ta-Tung , Lai Yiu-Kay , Hung Le-Mei
Published: January 2008

Boehmeria nivea extract (BNE) is widely used in southern Taiwan as a folk medicine for hepato‐protection and hepatitis treatment. In previous studies, we demonstrated that BNE could reduce the supernatant hepatitis B virus (HBV) DNA in HBV‐producing HepG2 2.2.15 cells. In the present study, we established an animal model of HBV viremia and used it to validate the efficacy of BNE in vivo. In this animal model, serum HBV DNA and HBsAg were elevated in accordance with tumor growth. To evaluate the anti‐HBV activity of BNE, HBV‐viremia mice were built up after one subcutaneous inoculation of HepG2 2.2.15 tumor cells in severe combined immunodeficiency mice over 13 days. The levels of serum HBV DNA were elevated around 105–106 copies per milliliter. Both oral and intraperitoneal administration of BNE were effective at inhibiting the production of HBsAg and HBV DNA, whereas tumor growth was not affected by all test articles. Intraperitoneal administration of BNE appeared to have greater potential to inhibit serum HBV DNA levels compared with oral administration under the same dosage. Notably, reduced natural killer cell activity was also observed after high dosage of BNE administration, and this correlated with reduced serum HBV DNA. In conclusion, BNE exhibited potential anti‐HBV activity in an animal model of HBV viremia.
Early postpartum symptoms in puerperal psychosis
Authors: Heron J , McGuinness M , Blackmore E Robertson , Craddock N , Jones I
Published: January 2008

Objective To examine the nature of the earliest reported symptoms in women who develop a bipolar affective puerperal psychosis (PP).

Design A retrospective interview study.

Setting Women were recruited for clinical and molecular genetic studies of PP from a national PP network, articles in the national press and referrals from UK specialist perinatal psychiatry services.

Sample One hundred and twenty‐seven women met the criteria for an episode of strictly defined bipolar affective PP developing within 4 weeks of childbirth.

Methods Participants were interviewed using the Schedule for clinical assessment in neuropsychiatry and hospital records were reviewed. Lifetime and puerperal episode diagnoses were made according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM‐IV) based on all the available information. During interview, participants were asked to describe the earliest symptoms they believed to be related to their illness onset. The day of onset for each symptom was recorded.

Main outcome measures We present subjectively experienced emotional and behavioural changes occurring within 3 days of childbirth, reported by four or more women.

Results Seventy‐three percent of women recalled experiencing an onset of symptoms by day 3. The most commonly recalled symptoms were feeling excited, elated or high (52%), not needing to sleep or not able to sleep (48%), feeling active or energetic (37%) and talking more or feeling very chatty (31%).

Conclusions Hypomanic symptoms are particularly characteristic of the early postpartum in women who develop PP. These types of symptoms should be carefully monitored in individuals at high risk of PP episodes.
Current concepts in bone and reproductive health in adolescents with anorexia nervosa
Authors: Jayasinghe Y , Grover SR , Zacharin M
Published: January 2008

Anorexia nervosa (AN) initiates an adaptive response at the level of the hypothalamus, which results in a complex interplay involving most elements of the neuroendocrine axis. Consequences of onset of disease in adolescence include amenorrhoea, pubertal arrest with potential loss of target height, and osteoporosis with reduced capacity for future attainment of peak bone mass. With recovery, delay in restoration of menses is common. Hormonal therapies for restoration of bone mineral density (BMD) in adolescents have shown limited efficacy. This review will discuss the reproductive endocrine effects of AN in adolescence, and discuss new investigative tools for monitoring restoration of reproductive function and BMD in this population.
Severe asphyxia due to delivery‐related malpractice in Sweden 1990–2005
Authors: Berglund S , Grunewald C , Pettersson H , Cnattingius S
Published: January 2008

Objective  To describe possible causes of delivery‐related severe asphyxia due to malpractice.

Design and setting  A nationwide descriptive study in Sweden.

Population  All women asking for financial compensation because of suspected medical malpractice in connection with childbirth during 1990–2005.

Method  We included infants with a gestational age of ≥33 completed gestational weeks, a planned vaginal onset of delivery, reactive cardiotocography at admission for labour and severe asphyxia‐related outcomes presumably due to malpractice. As asphyxia‐related outcomes, we included cases of neonatal death and infants with diagnosed encephalopathy before the age of 28 days.

Main outcome measure  Severe asphyxia due to malpractice during labour.

Results  A total of 472 case records were scrutinised. One hundred and seventy‐seven infants were considered to suffer from severe asphyxia due to malpractice around labour. The most common events of malpractice in connection with delivery were neglecting to supervise fetal wellbeing in 173 cases (98%), neglecting signs of fetal asphyxia in 126 cases (71%), including incautious use of oxytocin in 126 cases (71%) and choosing a nonoptimal mode of delivery in 92 cases (52%).

Conclusion  There is a great need and a challenge to improve cooperation and to create security barriers within our labour units. The most common cause of malpractice is that stated guidelines for fetal surveillance are not followed. Midwives and obstetricians need to improve their shared understanding of how to act in cases of imminent fetal asphyxia and how to choose a timely and optimal mode of delivery.
Vaginal surgery for pelvic organ prolapse using mesh and a vaginal support device
Authors: Carey M , Slack M , Higgs P , Wynn‐Williams M , Cornish A
Published: January 2008

Objectives  To describe a new surgical procedure for pelvic organ prolapse using mesh and a vaginal support device (VSD) and to report the results of surgery.

Design  A prospective observational study.

Setting  Two tertiary referral Urogynaecology practices.

Population  Ninety‐five women with International Continence Society pelvic organ prolapse quantification stage 2 or more pelvic organ prolapse who underwent vaginal surgery using mesh augmentation and a VSD.

Methods  Surgery involved a vaginal approach with mesh reinforcement and placement of a VSD for 4 weeks. At 6 and 12 months, women were examined for prolapse recurrence, and visual analogue scales for satisfaction were completed. Women completed quality‐of‐life (QOL) questionnaires preoperatively and at 6 and 12 months.

Main outcome measures  Objective success of surgery at 6 and 12 months following surgery. Secondary outcomes were subjective success, complications, QOL outcomes and patients’ satisfaction.

Results  Objective success rate was 92 and 85% at 6 and 12 months, respectively. Subjective success rate was 91 and 87% at 6 and 12 months, respectively. New prolapse in nonrepaired compartments accounted for 7 of 12 (58%) failures at 12 months. Two of 4 mesh exposures required surgery. Sexual dysfunction was reported by 58% of sexually active women preoperatively and 23% at 12 months. QOL scores significantly improved at 12 months compared with baseline (P < 0.0001).

Conclusion  Vaginal surgery using mesh and a VSD is an effective procedure for pelvic organ prolapse. However, further studies are required to establish the role of the surgery described in this study.
Inappropriate Use of Emergency Medical Services Transport: Comparison of Provider and Patient Perspectives
Authors: Richards John R. , Ferrall Stephen J.
Published: January 2008

Objectives: To determine the extent of inappropriate ambulance use from the perspectives of both emergency medical services (EMS) providers and patients utilizing EMS transport, assess level of agreement, and identify variables associated with inappropriate ambulance use. Methods: A prospective cross‐sectional study was done of a consecutive sample of patients arriving by ambulance during the month of February 1997 at an urban university hospital ED. EMS providers and patients completed a survey with questions regarding their perceptions of whether the need for ambulance transport was an emergency or a nonemergency. Patient demographic information and availability of alternate means of transportation to the hospital were also evaluated.

Results: Eight hundred eighty‐seven patients were included in the study. EMS providers thought that 501 patient transports were appropriate and represented true emergencies, whereas 689 patients believed their medical problems were true emergencies. A significant number of patients (n = 415, 47%) had access to alternative transportation to the hospital. Blunt traumatic injury and altered mental status were the most common reasons for EMS transport. Patient characteristics significantly associated with EMS provider perception of a true emergency were male gender, age >51 years, higher education, chest pain/cardiac complaints, shortness of breath/respiratory complaints, and Medicare insurance. Characteristics significantly associated with patients who perceived themselves to have true emergencies were black ethnicity, higher education, shortness of breath/respiratory complaints, and Medicare insurance. There was 75% agreement between EMS providers and patients on appropriateness of ambulance transport (kappa = 0.84). Conclusion: Inappropriate ambulance use is a significant problem from both EMS provider and patient perspectives. Certain patient characteristics are associated with a higher probability of appropriate and inappropriate uses of EMS transport. A large number of patients transported by ambulance have alternative means of transportation but elect not to use them.
What Is the Optimal Dose of Intramuscular Ketamine for Pediatric Sedation?
Authors: Green Steven M. , Hummel Christopher B. , Wittlake William A. , Rothrock Steven G. , Hopkins G. Alan , Garrett Wayne
Published: January 2008

Objective: The optimal dose of IM ketamine for ED procedural sedation in children is not known. The authors wished to quantify the dose‐response of ketamine with respect to sedation adequacy, time to discharge, and adverse effects in order to identify an optimal dose. Methods: The study was a consecutive case series of 1,022 children ≤15 years of age given IM ketamine in the EDs of a university medical center and an affiliated county hospital over a nine‐year period. Adequacy of sedation, time to discharge, and adverse effects were compared with dose administered. Results: Doses in the sample averaged 3.96 ± 0.69 mg/kg, with a range of 0.48 to 9.09 mg/kg. Children judged to be adequately sedated received higher doses compared with those inadequately sedated (3.94 ± 0.44 mg/kg vs 3.77 ± 0.49 mg/kg, p = 0.041), and a nonsignificant trend was noted toward uniformly adequate sedation with increasing dose (≤91% at <4.00 mg/kg, 93% at 4.00‐4.49 mg/kg, and 100% at ≥4.50 mg/kg). No significant difference or trend in time to discharge or adverse effects was noted between the children receiving <4.00 mg/kg and those receiving ≥4.00 mg/kg of ketamine, and the study had power (α= 0.05, β= 0.20) to detect a 9‐minute difference in times to discharge, a 3.3% difference in rates of airway complications, a 5.6% difference in rates of emesis, and a 12.3% difference in rates of recovery agitation. Conclusion: Ketamine doses of 4 to 5 mg/kg IM produced adequate sedation in 93%‐100% of children, suggesting that this dosing range may be optimal for ED procedural sedation. No difference in time to discharge or adverse effects was observed for lower or higher doses.
Osmol Gaps in the Pediatric Population
Authors: McQuillen Kemedy K. , Anderson Angela C.
Published: January 2008

Objective: To define the osmol gap (OG) range in pediatric ED (PED) patients. Methods: This was a blinded, observational patient series involving an urban PED with an annual census of 35,000. All patients presenting to the Hasbro Children's Hospital Emergency Department who required electrolyte determination during their evaluations were enrolled into the study. Exclusionary criteria included the presence of urinary ketones, alcohol ingestion within the preceding 24 hours, or illnesses that are known to change serum osmolarity. Electrolytes, BUN, glucose, and freezing point depression osmolality were measured on a single serum specimen. Additional laboratory information included ethanol and anion gap. The OG was determined using each of three equations previously described in the literature (see Results). The best coefficients for sodium, BUN, and glucose were determined by multiple linear regression. Results: 192 children (90 girls, 102 boys) with a median age of 6.6 years (mean: 7.3 years; range: 7 days to 17.9 years) made up the study population. The mean measured osmolality (± SD) for the entire sample was 284.2 ± 6.9 mOsm/dL with a range of 265‐311 mOsm/dL. Mean osmol gaps with standard deviations varied with the equation used for calculation. Conclusion: Regardless of the equation used, the range of “normal” osmol gaps in the pediatric population is approximately 22 mOsm.
EMS Systems: Foundations for the Future
Authors: O'Connor Robert E. , Cone David C. , De Lorenzo Robert A. , Domeier Robert M. , Moore Wayne E. , Taillac Peter P. , Verdile Vincent P. , Zachariah Brian S. , Davidson Steven J.
Published: January 2008

Emergency medical services (EMS) occupy a unique position in the continuum of emergency health care delivery. The role of EMS personnel is expanding beyond their traditional identity as out‐of‐hospital care providers, to include participation and active leadership in EMS administration, education, and research. With these roles come new challenges, as well as new responsibilities. This paper was developed by the SAEM EMS Task Force and provides a discussion of these new concepts as well as recommendations for the specialty of emergency medicine to foster the continued development of all of the potentials of EMS.
Research Fundamentals
Authors: Hall Kent N. , Kothari Rashmi U.
Published: January 2008

Once a research question or hypothesis has been derived, the investigatormust determine which research methodology can best answer his or her question. Prospective, randomized, controlled trials are often considered the sine qua non of research design. However, this study design is not always feasible, and often an alternate design will adequately answer the question at significantly less cost. All research designs have potential advantages and limitations. The decision of which study design to use is often a compromise between science and resources. This article was prepared by members of the SAEM Research Committee to describe the fundamental research concepts of research design. This paper defines different research methodologies and discusses their different uses, strengths, and weaknesses. It also describes the process of randomization and blinding. Finally, the concept of bias and its remedies is delineated.
Sleep Problems in Emergency Department Patients with Injuries
Authors: Goldberg Rochelle , Shah Sachin J. , Halstead Jeff , McNamara Robert M.
Published: January 2008

Objectives: To assess trauma patients frequency of sleep problems, to evaluate their injuries in the context of their sleep habits, and to determine how often ED health care workers (HCWs) inquire about sleep complaints. Methods: This was a prospective observational study of patients evaluated in the ED for unintentional trauma. Patients answered a “sleep survey” that was reviewed for the amount and timing of sleep in the preinjury period and for indications of a sleep problem. Preinjury sleep characteristics were compared with the individual's usual habits, and the group's sleep features were compared with “normal” sleep and the prevalence of sleep problems in historical controls. Results: Seventy patients were surveyed. Mechanisms and types of injury included motor vehicle collisions (MVCs), falls, lacerations, bruises, sprains, and fractures. The mean total sleep time in the preinjury period (6.9 hours) was significantly shorter than that obtained during usual weekday and weekend sleep. Twenty‐four patients (34.3%) were at high risk for a sleep problem. Few patients thought a sleep problem contributed to the injury. No other ED HCW asked about the patient's sleep habits. Conclusions: Acute sleep deprivation in the preinjury period, and chronic sleep deprivation with a variety of other sleep problems are found in this patient population. Despite the association of sleep problems and certain types of injury (e.g., MVC), ED HCWs do not inquire about sleep in their initial ED evaluations. This important issue may be overlooked in trauma risk assessment and prevention.
Emergency Medical Care: Types, Trends, and Factors Related to Nonurgent Visits
Authors: Liu Tiepu , Sayre Michael R. , Carleton Steven C.
Published: January 2008

Objectives: To describe and compare national trends in ED use by statistical analyses on data from the 1992 to 1996 National Hospital Ambulatory Medical Care Survey (NHAMCS) with a special interest in factors related to nonurgent visits. Methods: The NHAMCS collects data for ED visits using a four‐stage national probability sample. Data from 135,723 ED visits in 1992‐1996 were analyzed using the chi‐square test for proportions with logistic regression modeling for multivariate analysis. Results: More than half of the ED visits were considered nonurgent. There was a decreasing trend for nonurgent ED visits over the first three years of the sample (54.0% to 52.1%, p < 0.05). The proportion of ED visits for nonurgent care bounced back in 1995 (54.7%) and 1996 (54.1%). Significant variation existed in the proportion of nonurgent care visit based on disease category, age, race, and insurance coverage status. Marked variation in nonurgent visits also existed among geographic regions and types of hospital ownership. Conclusions: Analyses of data from the NHAMCS identify trends in ED use. The study of nonurgent ED visits with this database has inherent methodologic problems such as retrospective coding and geographic coding inconsistency. Since the nonurgent visit is clearly linked to certain social‐demographic factors, addressing these underlying issues by establishing a comprehensive health care system is a priority.