bluuebunny/crossref_metadata_2025 huggingface dataset:
Outdoor Vector Lab
Authors: Erdman Paul
Published: February 2004

Many students who take introductory physics at an algebra-based level on our campus have had little or no previous experience with vectors. These students must grasp the new mathematical tool as quickly as they can, for application is right around the corner. Often it is helpful to reinforce the concepts of vectors within the physics lab. However, the common physics lab involving force tables also throws in the concept of the force vector at a point where force has not yet been introduced, and the students are still trying to grasp the concept of vectors in terms of length and direction. To give my students a vector lab that focused on reinforcing the concept of vectors from the basics of length and direction, I devised an outdoor lab that forced them to use vectors in the solution of a problem that at first seemed straightforward.
Thin-Lens Equation Nomograph
Authors: Brown Ronald
Published: February 2004

A simple nomograph based on a general result from analytical geometry can be used to represent the solution of any problem in which the sum of reciprocals equals another reciprocal — that is, the equation that generates the hyperbolic function. One such relationship is the thin-lens formula often used in introductory physics courses. This discussion will show that the nomograph is necessarily consistent with both the ray diagram for a thin lens and the object-image distance relationship obtained in the typical introductory physics laboratory experiment to determine the focal length of a thin lens. It is also useful to display the focal length of the thin lens on the graph obtained in such an experiment.
Magnetic Forces Acting on Rigid Current-Carrying Wires Placed in a Uniform Magnetic Field
Authors: Casaca A. , Silva J. P.
Published: February 2004

We calculate the forces acting on segments of rigid wires carrying constant currents and placed in a uniform magnetic field. This example entices the students to formulate, explore, and prove a conjecture, exposing them to an early example of a research-like project. The sequence of examples discussed here was literally born during an introductory physics class period dedicated to the calculation of the forces acting on segments of current-carrying wires placed in a uniform magnetic field. On that occasion, a series of interchanges between the lecturer and the actively participating students led to the formulation of a conjecture, its exploration, and its final resolution. The resulting lecture was then spontaneously turned into an introduction (of sorts) to research in physics.
Student Explorations of Quantum Effects in LEDs and Luminescent Devices
Authors: Escalada Lawrence T. , Rebello N. Sanjay , Zollman Dean A.
Published: February 2004

We developed activity-based instructional units to introduce basic quantum principles to students with limited physics and mathematics backgrounds. To emphasize the practical applications of contemporary physics, we introduced concepts using the contexts of light-emitting devices such as light-emitting diodes (LEDs), fluorescent lamps, and glow-in-the-dark toys. As our standard of living becomes more dependent on the latest developments in science and technology, our students' literacy must be at a level that enables them to make educated decisions on science- and technology-related issues and their everyday applications. Students need to have at least a basic understanding of 20th-century physics and its applications in order to make informed decisions about them. Unfortunately, many physics teachers either exclude or spend very little time on modern topics such as quantum mechanics in high school physics courses.1,2 The high degree of mathematical formalism and abstract nature of quantum mechanics is frequently given as a reason for not introducing quantum physics in high school physics courses.3,4
The Flexible Faraday Cage
Authors: Gluck Paul
Published: February 2004

The Faraday ice-pail experiment is performed when studying the distribution of charges in conductors: Inside a hollow conductor the net charge is zero, and any excess charge resides on the outside surface.
EXACT SOLUTION, SCALING BEHAVIOUR AND QUANTUM DYNAMICS OF A MODEL OF AN ATOM-MOLECULE BOSE–EINSTEIN CONDENSATE
Authors: ZHOU HUAN-QIANG , LINKS JON , McKENZIE ROSS H.
Published: February 2004

We study the exact solution for a two-mode model describing coherent coupling between atomic and molecular Bose–Einstein condensates (BEC), in the context of the Bethe ansatz. By combining an asymptotic and numerical analysis, we identify the scaling behaviour of the model and determine the zero temperature expectation value for the coherence and average atomic occupation. The threshold coupling for production of the molecular BEC is identified as the point at which the energy gap is minimum. Our numerical results indicate a parity effect for the energy gap between ground and first excited state depending on whether the total atomic number is odd or even. The numerical calculations for the quantum dynamics reveals a smooth transition from the atomic to the molecular BEC.
FIELD THEORY RESULTS FOR THREE-DIMENSIONAL TRANSITIONS WITH COMPLEX SYMMETRIES
Authors: CALABRESE PASQUALE , PELISSETTO ANDREA , ROSSI PAOLO , VICARI ETTORE
Published: February 2004

We discuss several examples of three-dimensional critical phenomena that can be described by Landau–Ginzburg–Wilson ϕ4 theories. We present an overview of field-theoretical results obtained from the analysis of high-order perturbative series in the frameworks of the ∊ and of the fixed-dimension d=3 expansions. In particular, we discuss the stability of the O (N)-symmetric fixed point in a generic N-component theory, the critical behaviors of randomly dilute Ising-like systems and frustrated spin systems with noncollinear order, and the multicritical behavior arising from the competition of two distinct types of ordering with symmetry O (n1) and O (n2) respectively.
THERMODYNAMICS OF A BOSE GAS TRAPPED IN A BOUNDED HARMONIC POTENTIAL
Authors: LUMB SHALINI , MUTHU S. K.
Published: February 2004

Some thermodynamic features of an assembly of a finite number of bosons trapped in a bounded harmonic potential are investigated. P–V isotherms are drawn for both the degenerate and the non-degenerate phases. At any temperature, the pressure is a decreasing function of volume, unlike the free Bose gas for which the pressure becomes independent of volume in the degenerate phase. At the absolute zero of temperature the quantum pressure for a spherical enclosure of radius r0 equal to aho, aho being the characteristic harmonic oscillator length, is found to be of order 10-10 Torr while for [Formula: see text] it is of order 10-12 Torr. The isothermal compressibility has a sharp drop near the critical point and becomes negligibly small for temperatures above the critical temperature, irrespective of the size of the trap. The coefficient of thermal expansion also shows a sudden drop at the critical temperature. The specific heat at constant pressure shows a peak and is well-defined in the degenerate phase, in contradistinction to the ideal Bose gas. Results recently derived by Singh on the basis of local equilibrium theory are found to be in good agreement with our numerical computations.
CRITICAL SWITCHING BEHAVIOUR IN SPARSELY POPULATED SYSTEMS
Authors: METZLER RALF
Published: February 2004

The basic kinematic behaviour of a threshold switch in a system with a sparse population is investigated. We determine the basic quantities such as the number probability density function, the survival probability, the characteristic switching time, and the response to external triggering of the switch. The modelling approach is then extended to systems with response retardation, which, it is argued, may improve the stability of the switch.
EQUATION OF STATE AND FREEZING OF GMSA HARD SPHERES
Authors: MORADI M. , SHAHRI H.
Published: February 2004

The modified-weighted-density-functional approximation (MWDA) proposed by Denton and Ashcroft, is applied to study the equation of sate and freezing of the hard spheres using the generalized mean spherical approximation (GMSA) direct correlation function (DCF). Because of the attractive tail in the DCF, the perturbation method similar to that introduced by Yoon and Kim is applied. The free energy, freezing parameters and the equation of state of the hard sphere FCC crystal are obtained. The results are compared with some other previous theories and Monte Carlo simulation. Our results are in good agreement with the simulation results.
THE METALLIC NATURE OF BORON LAYERS IN MAGNESIUM DIBORIDE
Authors: ZHAO G. L. , PULLEN A. , BAGAYOKO D.
Published: February 2004

We performed ab initio, local density functional calculations for the electronic structure of MgB 2. The Fermi level of MgB 2 cuts through relatively narrow electron bands which have a dominant contribution from B (2p) states. The above metallic behavior of boron layers can also be seen from the calculated partial density of states. The metallic nature, strong covalent bonds, and the light atomic mass in the boron layers could lead to a strong electron-phonon (e–ph) interaction. The strong e–ph interaction is particularly important for the high energy phonons that are associated with boron layers in MgB 2.
SPIN CURRENT IN SPIN–ORBIT COUPLING SYSTEMS
Authors: HU JIANGPING , BERNEVIG BOGDAN A. , WU CONGJUN
Published: February 2004

We present a simple and pedagogical derivation of the spin current as the linear response to an external electric field for both Rashba and Luttinger spin–orbital coupling Hamiltonians. Except for the adiabatic approximation, our derivation is exact to the linear order of the electric field for both models. The spin current is a direct result of the difference in occupation levels between different bands. Moreover, we show a general topological spin current can be defined for a broad class of spin–orbit coupling systems.
EFFECTS OF DIELECTRIC MISMATCH ON THE PLASMONS IN QUANTUM WELL SYSTEMS
Authors: ZHANG XI-LI , WANG XUE-HUA , LIU XIN-HAI , GU BEN-YUAN
Published: February 2004

In the framework of random-phase approximation theory and applying the self-consistent field method, we study the properties of collective charge density excitations in single quantum well in consideration of dielectric mismatch. We analytically give the general solution of the image potential to the one dimensional Green's function. Our numerical results demonstrate that the dielectric mismatch between the barrier and well materials significantly changes the frequency of the intra- and inter-subband plasmon modes in contrast with dielectric match. We reasonably conclude that the image potential affects the intra- and inter-subband plasmon modes in a different way.
EFFECTS OF VARIATIONAL PARAMETER IN THE STUDY OF METAL–INSULATOR TRANSITION IN A QUASI-TWO DIMENSIONAL SEMICONDUCTOR SYSTEM
Authors: PETER A. JOHN
Published: February 2004

Effects of variational parameters on different dielectric functions in the study of semiconductor–metal transition are investigated for a shallow donor in an isolated well of GaAs/Ga 1-x Al s As superlattice system within the effective mass approximation. Vanishing of the donor ionization energy as a function of well width and donor concentration suggests that no transition is possible below a well width of 30 Å supporting the scaling theory of localization. The effects of Anderson localization, exchange and correlation in the Hubbard model are included in a simple way. The relationship between the present model and the Mott criterion in terms of Hubbard model is also brought out. The critical concentration is enhanced when the Hartree–Fock dielectric function is used. Results are compared with the existing data available and discussed in the light of existing literature.
THE STUDY OF SUPERCONDUCTING STATE PARAMETERS OF in-BASED BINARY ALLOYS BY PSEUDOPOTENTIAL
Authors: GAJJAR P. N. , VORA A. M. , PATEL MINAL H. , JANI A. R.
Published: February 2004

The study of the superconducting state parameters (SSP) viz. electron–phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature T C , isotope effect exponent α and effective interaction strength N0V of In-based binary alloys In 1-x Na x, In 1-x Mg x, In 1-x Zn x, In 1-x Tl x, In 1-x Sn x, In 1-x Pb x and In 1-x Bi x have been made extensively in the present work using a model potential. To explain electron–ion interaction pseudo-alloy-atom (PAA) model is applied for the first time instead of Vegard's Law. A considerable influence of various exchange and correlation functions on λ and μ* is found from the present study. It is also concluded that T C strongly depends on the value of the effective valence Z* of binary alloys.
ELECTRONIC STRUCTURE AND MAGNETISM OF NICKEL THIN FILMS
Authors: CHAKRABORTY MONODEEP , MOOKERJEE ABHIJIT , BHATTACHARYA ASHOK K.
Published: February 2004

We present calculations of the electronic and magnetic structure of thin films of Ni, using the recursion technique based on the tight-binding linearized muffin-tin orbitals basis. We find that the surface layers of free standing Ni thin films do carry enhanced magnetic moment.
RESONANT THz EMISSION IN A GRATING-COUPLED QUANTUM WELL DRIVEN BY DC CURRENT
Authors: HONG S. K. , SMETANIN I. V. , HAN H.
Published: February 2004

THz emission spectra from a grating-coupled two-dimensional plasmon system driven by DC current are calculated in a self-consistent manner. The emission peaks show strong resonant enhancement due to Smith–Purcell effect.
PRESSURE DEPENDENCE OF ELECTRON–IO-PHONON INTERACTION IN MULTI-INTERFACE HETEROSTRUCTURE SYSTEMS
Authors: YAN Z. W. , BAN S. L. , LIANG X. X.
Published: February 2004

The interface-optical (IO) phonon modes and their interaction with electrons in a multi-heterointerfaces structure are studied by using a transfer matrix method within the framework of the dielectric continuum model. The dispersion equation of IO phonon modes and the electron–IO-phonon (e– IO -p) interaction Hamiltonian are derived by considering the pressure effect. This method facilitates systematic calculations for complex structures where the conventional method is very difficult to implement. The numerical computation has been performed for a quantum well GaN/AlN system under pressure. The e– IO -p coupling related to the IO modes with the AlN LO-frequency (phonon energy 112.46 meV) at the long-wavelength limit is strongest in the four branches of IO-phonon modes. The result indicates that the IO-phonon modes and e– IO -p interaction coupling functions increase with pressure obviously.
FINITE TYPE INVARIANTS FOR SINGULAR SURFACE BRAIDS ASSOCIATED WITH SIMPLE 1-HANDLE SURGERIES
Authors: IWAKIRI MASAHIDE
Published: February 2004

S. Kamada introduced finite type invariants of knotted surfaces in 4-space associated with finger moves and 1-handle surgeries. In this paper, we define finite type invariants of surface braids associated with simple 1-handle surgeries and prove that a certain set of finite type invariants controls all finite type invariants. As a consequence, we see that every finite type invariant is not a complete invariant.
MARKOV TRACE ON THE YOKONUMA–HECKE ALGEBRA
Authors: JUYUMAYA J.
Published: February 2004

It is proved that the Yokonuma-Hecke algebra supports a Markov trace.
Molecular and functional characterization of common polymorphisms in HERG (KCNH2) potassium channels
Authors: Anson Blake D. , Ackerman Michael J. , Tester David J. , Will Melissa L. , Delisle Brian P. , Anderson Corey L. , January Craig T.
Published: February 2004

Long QT syndrome (LQTS) is a cardiac repolarization disorder that can lead to arrhythmias and sudden death. Chromosome 7-linked inherited LQTS (LQT2) is caused by mutations in human ether-a-go-go-related gene ( HERG; KCNH2), whereas drug-induced LQTS is caused primarily by HERG channel block. Many common polymorphisms are functionally silent and have been traditionally regarded as benign and without physiological consequence. However, the identification of common nonsynonymous single nucleotide polymorphisms (nSNPs; i.e., amino-acid coding variants) with functional phenotypes in the SCN5A Na+ channel and MiRP1 K+ channel β-subunit have challenged this viewpoint. In this report, we test the hypothesis that common missense HERG polymorphisms alter channel physiology. Comprehensive mutational analysis of HERG was performed on genomic DNA derived from a population-based cohort of sudden infant death syndrome and two reference allele cohorts derived from 100 African American and 100 Caucasian individuals. Amino acid-encoding variants were considered common polymorphisms if they were present in at least two of the three study cohorts with an allelic frequency >0.5%. Four nSNPs were identified: K897T, P967L, R1047L, and Q1068R. Wild-type (WT) and polymorphic channels were heterologously expressed in human embryonic kidney cells, and biochemical and voltage-clamp techniques were used to characterize their functional properties. All channel types were processed similarly, but several electrophysiological differences were identified: 1) K897T current density was lower than the other polymorphic channels; 2) K897T channels activated at more negative potentials than WT and R1047L; 3) K897T and Q1068R channels inactivated and recovered from inactivation faster than WT, P967L, and R1047L channels; and 4) K897T channels showed subtle differences compared with WT channels when stimulated with an action potential waveform. In contrast to K897T and Q1068R channels, P967L and R1047L channels were electrophysiologically indistinguishable from WT channels. All HERG channels had similar sensitivity to block by cisapride. Therefore, some HERG polymorphic channels are electrophysiologically different from WT channels.
Push-Pull Mechanism of Selective Attention in Human Extrastriate Cortex
Authors: Pinsk Mark A. , Doniger Glen M. , Kastner Sabine
Published: February 2004

Selective attention operates in visual cortex by facilitating processing of selected stimuli and by filtering out unwanted information from nearby distracters over circumscribed regions of visual space. The neural representation of unattended stimuli outside this focus of attention is less well understood. We studied the neural fate of unattended stimuli using functional magnetic resonance imaging by dissociating the activity evoked by attended (target) stimuli presented to the periphery of a visual hemifield and unattended (distracter) stimuli presented simultaneously to a corresponding location of the contralateral hemifield. Subjects covertly directed attention to a series of target stimuli and performed either a low or a high attentional-load search task on a stream of otherwise identical stimuli. With this task, target-search-related activity increased with increasing attentional load, whereas distracter-related activity decreased with increasing load in areas V4 and TEO but not in early areas V1 and V2. This finding presents evidence for a load-dependent push-pull mechanism of selective attention that operates over large portions of the visual field at intermediate processing stages. This mechanism appeared to be controlled by a distributed frontoparietal network of brain areas that reflected processes related to target selection during spatially directed attention.
Human potassium chloride cotransporter 1 (SLC12A4) promoter is regulated by AP-2 and contains a functional downstream promoter element
Authors: Zhou Guo-Ping , Wong Clara , Su Robert , Crable Scott C. , Anderson Kathleen P. , Gallagher Patrick G.
Published: February 2004

Most K-Cl cotransport in the erythrocyte is attributed to potassium chloride cotransporter 1 (KCC1). K-Cl cotransport is elevated in sickle erythrocytes, and the KCC1 gene has been proposed as a modifier gene in sickle cell disease. To provide insight into our understanding of the regulation of the human KCC1 gene, we mapped the 5′ end of the KCC1 cDNA, cloned the corresponding genomic DNA, and identified the KCC1 gene promoter. The core promoter lacks a TATA box and is composed of an initiator element (InR) and a downstream promoter element (DPE), a combination found primarily in Drosophila gene promoters and rarely observed in mammalian gene promoters. Mutational analyses demonstrated that both the InR and DPE sites were critical for full promoter activity. In vitro DNase I footprinting, electrophoretic mobility shift assays, and reporter gene assays identified functional AP-2 and Sp1 sites in this region. The KCC1 promoter was transactivated by forced expression of AP-2 in heterologous cells. Sequences encoding the InR, DPE, AP-2, and Sp1 sites were 100% conserved between human and murine KCC1 genes. In vivo studies using chromatin immunoprecipitation assays with antihistone H3 and antihistone H4 antibodies demonstrated hyperacetylation of this core promoter region. (Blood. 2004;103:4302-4309)
Plasticity of endothelial cells: rapid dedifferentiation of freshly isolated high endothelial venule endothelial cells outside the lymphoid tissue microenvironment
Authors: Lacorre Delphine-Armelle , Baekkevold Espen S. , Garrido Ignacio , Brandtzaeg Per , Haraldsen Guttorm , Amalric François , Girard Jean-Philippe
Published: February 2004

Endothelial cells display remarkable heterogeneity in different organs and vascular beds. Although many studies suggest that tissues “speak” to endothelial cells, endothelial cell diversity remains poorly characterized at the molecular level. Here, we describe a novel strategy to characterize tissue-specific endothelial cell phenotypes and to identify endothelial cell genes that are under the control of the local microenvironment. By comparing post-capillary high endothelial venule endothelial cells (HEVECs), freshly isolated from human tonsils without any cell culture step, with HEVECs cultured for 2 days, we found that HEVECs rapidly lost their specialized characteristics when isolated from the lymphoid tissue microenvironment. Striking changes occurred as early as after 48 hours, with complete loss of the postcapillary venule–specific Duffy antigen receptor for chemokines (DARCs) and the HEV-specific fucosyltransferase Fuc-TVII. DNA microarray analysis identified several other candidate HEV genes that were rapidly down-regulated ex vivo, including type XV collagen, which we characterized as a novel, abundant HEV transcript in situ. Together, our results demonstrate that blood vessel type–specific and tissue-specific characteristics of endothelial cells are under the control of their microenvironment. Therefore, even short-term primary cultures of human endothelial cells may not adequately mimic the differentiated endothelial cell phenotypes existing in vivo.
The Tie-2 ligand Angiopoietin-2 is stored in and rapidly released upon stimulation from endothelial cell Weibel-Palade bodies
Authors: Fiedler Ulrike , Scharpfenecker Marion , Koidl Stefanie , Hegen Anja , Grunow Verena , Schmidt Jarno M. , Kriz Wilhelm , Thurston Gavin , Augustin Hellmut G.
Published: February 2004

The angiopoietins Ang-1 and Ang-2 have been identified as ligands with opposing functions of the receptor tyrosine kinase Tie-2 regulating endothelial cell survival and vascular maturation. Ang-1 acts in a paracrine agonistic manner, whereas Ang-2 appears to act primarily as an autocrine antagonistic regulator. To shed further light on the complexity of autocrine/paracrine agonistic/antagonistic functions of the angiopoietin/Tie-2 system, we have studied Ang-2 synthesis and secretion in different populations of wild-type and retrovirally Ang-2–transduced endothelial cells. Endogenous and overexpressed endothelial cell Ang-2 is expressed in a characteristic granular pattern indicative of a cytoplasmic storage granule. Light and electron microscopic double staining revealed Ang-2 colocalization with von Willebrand factor, identifying Ang-2 as a Weibel-Palade body molecule. Costaining with P-selectin showed that storage of Ang-2 and P-selectin in Weibel-Palade bodies is mutually exclusive. Stored Ang-2 has a long half-life of more than 18 hours and can be secreted within minutes of stimulation (eg, by phorbol 12-myristate 13-acetate [PMA], thrombin, and histamine). Collectively, the identification of Ang-2 as a stored, rapidly available molecule in endothelial cells strongly suggests functions of the angiopoietin/Tie-2 system beyond the established roles during angiogenesis likely to be involved in rapid vascular homeostatic reactions such as inflammation and coagulation.
Evidence for anti-inflammatory activity of statins and PPARα activators in human C-reactive protein transgenic mice in vivo and in cultured human hepatocytes in vitro
Authors: Kleemann Robert , Verschuren Lars , de Rooij Bert-Jan , Lindeman Jan , de Maat Moniek M. , Szalai Alexander J. , Princen Hans M. G. , Kooistra Teake
Published: February 2004

Inflammatory processes, aside from cholesterol, play a central role in atherogenesis. Human C-reactive protein (huCRP) signals systemic inflammation and independently predicts future cardiovascular risk. Cholesterol-lowering statins reduce atherosclerosis and plasma huCRP levels. Evidence is sought for a direct anti-inflammatory statin effect in vivo, independent of effects on plasma cholesterol and atherogenesis. The effect of atorvastatin and simvastatin on huCRP expression was studied in nonatherosclerotic huCRP transgenic mice and compared with another class of hypolipidemic drugs, peroxisome proliferator-activated receptor-alpha (PPARα) activators, notably fenofibrate and Wy14643. Like statins, PPARα activators combine antiatherosclerotic properties with huCRP-lowering effects. Dietary treatment with statins or PPARα activators decreased basal and interleukin-1β (IL-1β)-induced plasma huCRP levels independently of cholesterol lowering. These direct anti-inflammatory in vivo effects occurred at the transcriptional level and could be confirmed in cultured human liver slices and in human hepatoma cells transiently transfected with a huCRP promoter-driven luciferase reporter. A molecular rationale for the suppression of IL-1-induced huCRP transcription is provided by showing that statins and PPARα activators up-regulate IκBα protein expression. This results in a reduced nuclear translocation of p50-nuclear factor κ B (NFκB) and thereby decreased amounts of nuclear p50-NFκB∼CCAAT/enhancer binding protein beta (C/EBPβ) complexes, which determine the huCRP transcription rate. Our results provide conclusive evidence for a direct suppressive effect of statins and PPARα activators on huCRP expression independent of cholesterol lowering and atherogenesis. (Blood. 2004;103:4188-4194)
The occurrence of graft-versus-host disease is the major predictive factor for response to donor lymphocyte infusions in multiple myeloma
Authors: Lokhorst Henk M. , Wu Kalung , Verdonck Leo F. , Laterveer Laurens L. , van de Donk Niels W. C. J. , van Oers Marinus H. J. , Cornelissen Jan J. , Schattenberg Anton V.
Published: February 2004

The graft-versus-myeloma (GVM) effect of donor lymphocyte infusions (DLIs) is well established. We now report the outcome of DLI in 54 patients with relapsed myeloma following allogeneic transplantation. Twenty-eight patients (52%) responded, 19 patients (35%) with a partial response and 9 patients (17%) with a complete response. Progression-free and overall survival were 19 and 23 months, respectively. We found that acute and chronic graft-versus-host disease (GVHD) observed in 57% and 47% of patients, respectively, following DLI were the strongest predictors for response. This suggests that targets for GVHD and GVM are identical. In a subgroup analysis, deletion of chromosome 13, as determined by double-color fluorescence in situ hybridization (FISH), had no impact on outcome, indicating that these patients are candidates for early allogeneic transplantation followed by DLI, in case of insufficient response. (Blood. 2004;103:4362-4364)
Efficient gene transfer into rhesus repopulating hematopoietic stem cells using a simian immunodeficiency virus–based lentiviral vector system
Authors: Hanawa Hideki , Hematti Peiman , Keyvanfar Keyvan , Metzger Mark E. , Krouse Allen , Donahue Robert E. , Kepes Steve , Gray John , Dunbar Cynthia E. , Persons Derek A. , Nienhuis Arthur W.
Published: February 2004

High-titer, HIV-1–based lentiviral vector particles were found to transduce cytokine-mobilized rhesus macaque CD34+ cells and clonogenic progenitors very poorly (< 1%), reflecting the postentry restriction in rhesus cells to HIV infection. To overcome this barrier, we developed a simian immunodeficiency virus (SIV)–based vector system. A single exposure to a low concentration of amphotropic pseudotyped SIV vector particles encoding the green fluorescent protein (GFP) resulted in gene transfer into 68% ± 1% of rhesus bulk CD34+ cells and 75% ± 1% of clonogenic progenitors. Polymerase chain reaction (PCR) analysis of DNA from individual hematopoietic colonies confirmed these relative transduction efficiencies. To evaluate SIV vector–mediated stem cell gene transfer in vivo, 3 rhesus macaques underwent transplantation with transduced, autologous cytokine-mobilized peripheral blood CD34+ cells following myeloablative conditioning. Hematopoietic reconstitution was rapid, and an average of 18% ± 8% and 15% ± 7% GFP-positive granulocytes and monocytes, respectively, were observed 4 to 6 months after transplantation, consistent with the average vector copy number of 0.19 ± 0.05 in peripheral blood leukocytes as determined by real-time PCR. Vector insertion site analysis demonstrated polyclonal reconstitution with vector-containing cells. SIV vectors appear promising for evaluating gene therapy approaches in nonhuman primate models.
Exploring the spiritual needs of people dying of lung cancer or heart failure: a prospective qualitative interview study of patients and their carers
Authors: Murray Scott A , Kendall Marilyn , Boyd Kirsty , Worth Allison , Benton T Fred
Published: February 2004

Background: We set out to explore whether patients with life-threatening illnesses and their informal carers consider they experience significant spiritual needs, in the context of their overall needs, how spiritual concerns might vary by illness group and over the course of the illness, and how patients and their carers think they might be supported in addressing spiritual issues. Methods: Three-monthly qualitative interviews for up to one year with 20 patients with inoperable lung cancer and 20 patients with end-stage heart failure and their informal carers. Results: We conducted 149 in-depth interviews. Spiritual concerns were important for many patients in both groups, both early and later in the illness progression. Whether or not patients and carers held religious beliefs, they expressed needs for love, meaning, purpose and sometimes transcendence. The different experiences of lung cancer and heart failure raised contrasting patterns of spiritual issues and needs. Carers voiced their own spiritual needs. Patients and carers were generally reluctant to raise spiritual issues, but many, in the context of a developing relationship with the researcher, were able to talk about such needs. Conclusions: Spiritual issues were significant for many patients in their last year of life and their carers. Many health professionals lack the necessary time and skills to uncover and address such issues. Creating the opportunity for patients and carers to discuss spiritual issues, if they wish, requires highly developed communication skills and adequate time.
Does psychosocial intervention improve survival in cancer? A meta-analysis
Authors: Chow Edward , Tsao May N , Harth Tamara
Published: February 2004

Background: There is growing evidence that positive psychosocial intervention improves the wellbeing of cancer patients. Two meta-analyses conducted to date confirmed a significant small-to-moderate effect on quality of life. Previous randomized trials reported that psychosocial intervention also improved survival. However, more recent trials failed to detect a difference in survival. A systematic review of randomized trials that have examined the effectiveness of psychosocial intervention in cancer patients in terms of survival prolongation was conducted. Methods: Randomized trials published between 1966 and June 2002 were identified through the databases of MEDLINE, EMBASE, CancerLit, CINAHL, Cochrane Library and reference lists of relevant articles. Relevant data were abstracted. The results of randomized trials were pooled using meta-analyses to estimate the effect of treatment on overall survival at one and four years in all cancer patients and also in breast cancer patients with metastases. Results: Eight trials, which involved a total of 1062 patients (all cancer histologies), were identified. One-and four-year overall survival rates were obtained from eight trials and six trials, respectively. There was no statistically significant difference in the overall survival rates at one and four years [P=0.6; RR 0.94 (95% CI 0.72, 1.22)] and [P=0.5; RR 0.93 (95% CI 0.77, 1.13)], respectively. Four trials examined 511 metastatic breast cancer patients. Again, there was no statistically significant difference in the overall survival rates at one and four years [P=0.3; RR 0.87 (95% CI 0.67, 1.14)] and [P=0.3; RR 0.91 (95% CI 0.76, 1.10)], respectively. Conclusions: Psychosocial intervention does not prolong survival in cancer. This meta-analysis can not rule out small effect sizes because of the small number of trials and small trial sizes.
Gabapentin in the treatment of neuropathic pain
Authors: Bennett Michael I , Simpson Karen H
Published: February 2004

This paper reviews the pharmacology and clinical effectiveness of gabapentin in the treatment of neuropathic pain. Gabapentin has antihyperalgesic and antiallodynic properties but does not have significant actions as an anti-nociceptive agent. Its mechanisms of action appear to be a complex synergy between increased GABA synthesis, non-NMDA receptor antagonism and binding to the α2δ subunit of voltage dependent calcium channels. The latter action inhibits the release of excitatory neurotransmitters. Clinically, several large randomized controlled trials have demonstrated its effectiveness in the treatment of a variety of neuropathic pain syndromes. Patients with neuropathic pain can expect a mean reduction in pain score of 2.05 points on an 11 point numerical rating scale compared with a reduction of 0.94 points if they had taken the placebo. Around 30% of patients can expect to achieve more than 50% pain relief and a similar number will also experience minor adverse events; the most common of which are somnolence and dizziness. In patients with neuropathic pain due to cancer, higher response rates might be observed with gabapentin when administered with opioids because of a synergistic interaction.
Get out of jail free? The doctrine of double effect in English law
Authors: Huxtable Richard
Published: February 2004

The ethical doctrine of double effect permits health care professionals to administer potentially fatal medication, provided that their intentions are purely to control symptoms. In this article, the legal status and scope of the doctrine will be analysed, and it will be argued that the law in this context is unclear, incoherent and partial in its application. The problems are not exclusively legal in nature, however, because health professionals have been critical both of the doctrine itself and of the lawyers' understanding of the concept. It will be concluded that clarification and appropriate enforcement are needed if the doctrine and the law are to retain credibility.
Has CONSORT improved the reporting of randomized controlled trials in the palliative care literature? A systematic review
Authors: Piggott M , McGee H , Feuer D
Published: February 2004

Background: In 1996, the CONSORT (CONsolidated Standards Of Reporting Trials) statement for the reporting of clinical trials was produced, based on empirical evidence regarding bias. Aims: This study assessed the quality of reporting of randomized controlled trials (RCTs) in the palliative care literature. Methods: Three specialist journals were hand searched for RCTs. A checklist was devised based on CONSORT recommendations. Two investigators independently assessed all the trials against this checklist. The trials were grouped into time cohorts of five years and quality comparisons made. Trials looking at pain were compared with those trials looking at other aspects of palliative care. Results: Ninety-three RCTs were identified. The number of trials has increased over time: nine in the first cohort, 37 in the second and 47 in the last cohort. The number of patients in the individual trials has also increased over time. Generally, the reporting quality was poor, particularly the areas of allocation concealment, randomization technique and intention to treat analysis, where there is empirical evidence, that it leads to trial bias. Although there were more pain papers than non-pain papers, the quality of reporting was only better for blinding and intention to treat analysis. Conclusion: The quality of reporting of RCTs in the palliative care literature is generally poor. However, there has been an increase in the number and the size of RCTs being carried out. This shows recognition of the importance of an evidence base in palliative care. However, in order to guide clinical decision making, future trials need to improve the quality of their reporting by adhering to the CONSORT statement.
6-Amino-6-deoxychitosan. Preparation and Application as Plasmid Vector in COS-1 Cells
Authors: Satoh Taku , Nagasaki Takeshi , Sakairi Nobuo , Shinkai Seiji
Published: February 2004

6-Amino-6-deoxychitosan was prepared from 6-deoxy-6-halo-N-phthaloylchitosan via 6-azidation. The product has high stereoregularity because of the effective and regioselective reactions. To evaluate 6-amino-6-deoxychitosan as a gene transfer agent, transfection efficiencies of its complexes with plasmid DNA in COS-1 cells were examined.
Controlled Assembly of Dinuclear Metallorings into 1D Coordination Polymer and Mixed-metal Rare Earth Complexes with Red-to-Green Luminescence Properties
Authors: Cai Zheng-Hong , Tang Yu , Liu Wei-sheng , Tan Min-Yu
Published: February 2004

Novel rings connected by chains 1D coordination polymer of rare earth complex have been rationally synthesized by the reaction of Eu(NO3)3·6H2O and L, 1,4-bis{[(2′-benzylaminoformyl)phenoxyl]methyl}benzene. The functional terminal groups (N-benzylsalicylamide) can activate both Eu3+ and Tb3+ to give out their characteristic lights and the mixed-metal complexes of different ratio of these metals have also been prepared. According to the principle of paints, these complexes give out red-to-green luminescence under UV light, so the complexes with yellow and orange luminescence properties have been realized.
Spin-coating Preparation of High Quality Mesoporous Titania Nanofilms
Authors: Bao Ningzhong , Yanagisawa Kazumichi , Lu Xiaohua , Feng Xin
Published: February 2004

Highly ordered crack-free mesoporous titania nanofilms with crystalline anatase framework are obtained by spin-coating glass surface, using the very acidic solution containing ethanol, H2O, TiCl4, and P123 (Pluronic P123, an triblock copolymer H(OCH2CH2)20(OCH(CH3)CH2)70(OCH2CH2)20OH)).
Heck-type Benzylation of Olefins with Benzyl Trifluoroacetates
Authors: Narahashi Hirohisa , Yamamoto Akio , Shimizu Isao
Published: February 2004

A new synthetic method for 1-aryl-2-alkenes from 1-olefins by benzylation treating with benzyl trifluoroacetates using palladium-catalyst is developed on the basis of oxidative addition of benzyl carboxylates to Pd(0) complexes to give benzyl(carboxylato)palladium(II) complexes with cleavage of benzyl–oxygen bond.
A Tripodal Ligand Containing Three Imidazole Groups Inducing Spin Crossover in Both Fe(II) and Fe(III) Complexes; Structures and Spin Crossover Behaviors of the Complexes
Authors: Ohta Hiromi , Sunatsuki Yukinari , Kojima Masaaki , Iijima Seiichiro , Akashi Haruo , Matsumoto Naohide
Published: February 2004

A tripodal hexadentate ligand containing three imidazole groups gives spin-crossover iron complexes in both the +II and the +III oxidation states. The tetrafluoroborate salt of the Fe(II) complex shows a gradual spin transition in the temperature range 110–270 K. The corresponding Fe(III) complex shows a spin transition above 150 K, and at 300 K ca. 87% of the Fe(III) ion is in the high-spin state.
Novel 1-D Water Nanowires in Crystal of an Organic Host
Authors: Wakahara Akio , Ishida Toshimasa
Published: February 2004

Novel infinite columnar/helical structures of hydrogen-bonded water molecules in an organic host crystal, constructed by the crystallographic symmetry operation, provide the structural scaffold for evaluating one-dimensional water nanowires.
European Concerted Action on Anticoagulation. Quality Assessment of the CoaguChek Mini and TAS PT-NC Point-of-Care Whole-Blood Prothrombin Time Monitors
Authors: Poller Leon , Keown Michelle , Chauhan Nikhil , van den Besselaar Anton M H P , Tripodi Armando , Shiach Caroline , Jespersen Jorgen
Published: February 2004

Background: International Normalized Ratios (INRs) for prothrombin time obtained with the CoaguChek Mini and TAS (RapidPointCoag) PT-NC systems are markedly different and also differ from the “true” INR. There is therefore a need for local quality assessment (QA) of the two systems.

Methods: A set of 60 lyophilized artificially depleted and 60 lyophilized coumarin plasmas were tested at 10 centers on both point-of-care testing monitors. Subsets of three and five plasmas were selected as QA plasmas and compared with the remaining 55 to assess the relative ability of the systems to characterize performance at the individual centers. The incidence of aberrant results (outliers; >15% deviation from the true INR) was also recorded. The expected incidence with the QA plasmas was calculated and compared.

Results: On both systems, INR with the common sets of 55 lyophilized plasmas varied considerably between centers. With the TAS PT-NC, subsets of five and three European Concerted Action on Anticoagulation (ECAA) artificially depleted plasmas gave good correlation with the 55 plasmas, but the coumarin plasmas performed less well. With the CoaguChek Mini, correlation was good with sets of five artificially depleted QA plasmas and reasonable with three but was less satisfactory with the coumarin plasmas. Outliers were detected with both types of plasmas on both test systems but with variable success.

Conclusions: With the TAS PT-NC, three ECAA artificially depleted lyophilized plasmas provided reliable QA, but five lyophilized coumarin plasmas were required. With the CoaguChek Mini, five artificially depleted plasmas gave reliable QA but coumarin plasmas gave poorer results. ECAA QA plasmas provide a local system for checking INRs obtained with monitors of both types.
De Novo Biosynthesis and Radiolabeling of Mammalian Digitalis-Like Factors
Authors: Qazzaz Hassan M A M , Cao (Tim) Zhimin , Bolanowski Duane D , Clark Barbara J , Valdes Roland
Published: February 2004

Background: Digoxin-like immunoreactive factors (DLIFs) are endogenous mammalian cardenolides with structural features similar to those of the plant-derived digitalis compounds. DLIFs and their structurally related forms (Dh-DLIFs) may serve as effectors of ion-transport activity mediated by their interaction with Na,K-ATPase and thus play a role as a new hormonal axis. Although some evidence implicates the adrenal gland as a tissue source for the DLIFs, little is known about the biosynthetic pathway producing these compounds. We now demonstrate de novo biosynthesis of DLIF by incorporation of radioactive carbon (14C) into the structures of both DLIF and Dh-DLIF.

Methods: We used a combination of reversed-phase HPLC techniques to separate the radioactive DLIF components after incorporation of 14C into their structure by use of either [1,2-14C]acetic acid or [4-14C]cholesterol as precursors and a Y-1 mouse adrenocortical tumor cell line. We also stimulated and suppressed production of steroidogenesis by use of cAMP analogs and Mevastatin, respectively, to demonstrate the dependence of DLIF production on the cholesterol-dependent biosynthetic pathway. A combination of chromatographic mobility, immunoassays specific for digoxin and dihydrodigoxin, and deglycosylation using 5-sulfosalicylic acid were used to identify the DLIF and Dh-DLIF components.

Results: With cholesterol as precursor, the cells produced DLIF (7.5 mCi/mmol) with a labeling efficiency of 10%, whereas with acetate the cells produced DLIF (72.2 mCi/mmol) with a labeling efficiency of 0.08% of the total DLIF produced. The radiolabeled DLIF and Dh-DLIF molecules had identical chromatographic mobilities and stoichiometric removal of sugars as the previously characterized DLIFs isolated from different mammalian species and tissues. With radioactive cholesterol as precursor, the 14C was incorporated into the DLIF-genin portion of the compounds and not the sugars. Interestingly, treatment of Y-1 cells with 8-bromoadenosine 3′:5′-cAMP to stimulate steroidogenesis did not increase production of DLIF or Dh-DLIF but did increase production of progesterone. Mevastatin (5 μmol), an inhibitor of the enzyme hydroxymethylglutaryl-CoA reductase and thus of cholesterol biosynthesis, gave an 85% decrease in the production of 14C-DLIF and progesterone, but only a modest 15% decrease in 14C-Dh-DLIF production.

Conclusions: These data demonstrate that the adrenal cell has the cellular machinery necessary for de novo biosynthesis of DLIF and Dh-DLIF starting from a simple carbon pool and also support the concept that cholesterol is a major precursor of the DLIF compounds. This cell culture model provides a source of radiolabeled DLIF compounds for future experimental work.
Interlaboratory Comparison of Fetal Male DNA Detection from Common Maternal Plasma Samples by Real-Time PCR
Authors: Johnson Kirby L , Dukes Kimberly A , Vidaver John , LeShane Erik S , Ramirez Idania , Weber William D , Bischoff Farideh Z , Hahn Sinuhe , Sharma Arun , Dang Dianne X , Hire Lisa M , Bianchi Diana W , Simpson Joe Leigh , Holzgreve Wolfgang , Elias Sherman , Klinger Katherine W
Published: February 2004

Background: Analysis of fetal DNA from maternal plasma by PCR offers great potential for noninvasive prenatal genetic diagnosis. To further evaluate this potential, we developed and validated a standard protocol to determine whether fetal DNA sequences could be reproducibly amplified and measured across multiple laboratories in a common set of specimens.

Methods: Each of five participating centers in a National Institute of Child Health and Human Development consortium collected 20 mL of peripheral blood from 20 pregnant women between 10 and 20 weeks of gestation. The plasma fraction was separated according to a common protocol, divided, and frozen in five aliquots. One aliquot was shipped to each participating laboratory, where DNA was extracted according to a standard protocol. All plasma samples (n = 100) were then analyzed blindly for the presence and quantity of total DNA (GAPDH) and male fetal DNA (SRY) by real-time PCR. Genomic DNA was isolated from female and male cells at one center, quantified, and shipped to the others to serve as calibrators for GAPDH and SRY, respectively.

Results: The amplification of known quantities of DNA was consistent among all centers. The mean quantity of male DNA amplified from maternal plasma when the fetus was male ranged from 51 to 228 genome equivalents (GE)/mL. Qualitative concordance was found overall among centers. The sensitivity of the assay for detection of male DNA when the fetus was male varied from 31% to 97% among centers. Specificity was more consistent (93–100%) with only four false-positive results obtained across the entire study.

Conclusions: All centers were able to consistently amplify frozen and shipped DNA. The PCR procedure used here is reliable and reproducible. Centers that extracted and amplified more DNA per milliliter of maternal plasma had superior sensitivities of Y chromosome sequence detection. The specificity of the assay was more consistent among centers. A robust and thoroughly optimized protocol for the extraction of DNA from maternal plasma is needed to make testing of fetal DNA in maternal plasma a clinically relevant analytical tool.