bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite Element Method Evaluation: Articulations and Diagonals in an 8‐Pin Type 1B External Skeletal Fixator
Authors: Lauer Susanne K. , Aron Dennis N. , Evans Mark D.
Published: April 2004

Objective—To determine the mechanical properties of articulations and diagonals in an 8‐pin type 1b external skeletal fixator (ESF).

Study Design—Finite element method—computer simulation.

Methods—The control type 1b ESF was supplemented with different articulations and diagonals. The parameters of frame angle, articulation diameter, and pin‐ or connector‐based fastening were altered. The configurations were loaded for axial compression, torsion, and craniocaudal and mediolateral bending as single loads and as a combination. Three‐dimensional linear and rotational gap strain and Von Mises stress maxima were determined.

Results—For 90°, 60°, and 30° frame angles and 0.48‐cm‐diameter articulations and diagonals, the best configurations, based on lower gap strain combined with decreased or minimally increased stress maxima for the combined load, were single or double diagonals or four horizontal articulations. Combining double diagonals with double wide horizontal articulations further lowered gap strain. For a 90° frame angle and 0.32‐cm‐diameter articulations and diagonals, the superior configurations, showing the lowest gap strain combined with decreased or minimally increased stress maxima for the combined load, were double diagonals, four horizontal, or wide double horizontal articulations. The 0.48‐cm articulations and diagonals provided lower or similar gap strain than 0.32‐cm articulations and diagonals. The connector‐to‐connector version of these superior configurations provided slightly lower or similar gap strain and stress maxima than the pin‐to‐pin version. Only pin‐to‐pin–fastened double diagonals provided better stress maxima than the corresponding connector‐to‐connector version.

Conclusions—Supplementing a type 1b ESF with double diagonals and wide double articulations results in the greatest increase in stability at the fracture gap for complex fractures or in the initial phase of bone healing.
Effects of Analgesia of the Distal Interphalangeal Joint or Palmar Digital Nerves on Lameness Caused by Solar Pain in Horses
Authors: Schumacher John , Steiger Ruedi , Schumacher Jim , de Graves Fred , Schramme Michael , Smith Roger , Coker Mike
Published: April 2004

Objective— To determine if pain of the dorsal margin of the sole in horses can be attenuated by anesthesia of either the distal interphalangeal (DIP) joint or the palmar digital (PD) nerves.

Study Design— A unilateral forelimb lameness was induced by creating solar pain. Response to administration of local anesthetic or saline solution into the DIP joint and to administration of local anesthetic around the PD nerves was evaluated.

Animals— Six horses.

Methods— Lameness was induced by creating pressure on the dorsal margin of the sole by screwing set‐screws into a nut welded to the inside of each branch of a shoe. Gaits were evaluated before and after application of set‐screws and after a local anesthetic or saline solution was administered into the DIP joint and, in a second trial, after a local anesthetic was injected around the PD nerves. Gaits recorded on videotape were evaluated, and lameness scores were assigned to each gait.

Results— Lameness scores were high after application of set‐screws and remained high after saline solution was administered into the DIP joint. Scores decreased significantly (P≤ .05) after a local anesthetic was administered into the DIP joint or around the PD nerves.

Conclusions— Analgesia of the DIP joint or the PD nerves desensitizes at least a portion of the sole.

Clinical Relevance— Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the DIP joint or PD nerves.
Neurocysticercosis
Authors: DeGiorgio Christopher M. , Medina Marco T. , Durón Reyna , Zee Chi , Escueta Susan Pietsch
Published: April 2004

Neurocysticercosis is a leading cause of seizures and epilepsy in the developing world and is an increasingly important health issue in the United States. Recent results from the Cysticercosis Working Group in Peru provide new evidence supporting the use of antiparasitic agents in highly selected patients with active cysts and seizures.
Incidence and Predictors of Major Vascular Complications after Percutaneous Coronary Intervention in the Glycoprotein IIb/IIIa Platelet Inhibitor Era
Authors: KONSTANCE RICHARD , TCHENG JAMES E. , WIGHTMAN MARILYN B. , KELLY LARRY P. , MOORE ANNETTE , HARRISON J. KEVIN , SKETCH MICHAEL H.
Published: April 2004

Since the introduction of platelet glycoprotein (GP) IIb/IIIa inhibitors, reports of vascular complications after percutaneous coronary intervention (PCI) have focused on bleeding and the need for surgical repair, whereas specific major vascular complications have been less consistently identified. Moreover, data from clinical trials may lack applicability to the general population. The purpose of this study was to determine the incidence of major vascular complications after PCI and to identify associated risk factors in patients routinely receiving GP IIb/IIIa inhibitors. During a 12‐month period, 1,634 consecutive patients underwent PCI at a single institution. Clinical characteristics and procedural data were collected prospectively; data regarding vascular sheath removal were obtained retrospectively. Univariate and multivariable regression methods were used to identify independent predictors of major vascular complications. Major vascular complications occurred in 2.9% of patients. Multivariable analysis revealed advanced age (odds ratio [OR] 1.05, P = 0.0025) and female sex (OR 2.9, P = 0.0002) as clinical characteristics associated with major vascular complications, whereas hypertension had an inverse relationship (OR 0.46, P = 0.013). Procedural factors included use of the following: stents (OR 5.59, P < 0.0001), vascular sheaths >6F (OR 3.25, P = 0.016), and mechanical clamp (OR 2.71, P = 0.0012). The presence of a hematoma >4 cm2 had a positive predictive value of 12% for major vascular complications. The incidence of major vascular complications in this large, single‐center study from the GP IIb/IIIa inhibitor era is consistent with data from the pre‐GP IIb/IIIa inhibitor era and recent randomized trials. (J Interven Cardiol 2004;17:65–70)
Transcatheter Closure of Congenital Muscular Ventricular Septal Defect
Authors: ARORA RAMESH , TREHAN VIJAY , THAKUR ASHISH K. , MEHTA VIMAL , SENGUPTA P. P. , NIGAM M.
Published: April 2004

The success with occlusion devices for the closure of atrial septal defects and patent ductus arteriosus prompted the transcatheter closure of single and multiple muscular ventricular septal defects (VSD). The procedure for VSD was first attempted by Lock et al. in 1988 and devices originally designed for the closure of other intracardiac defects (Rashkind umbrella device, Lock clamshell, Cardioseal, coils, Sideris buttoned device etc.) were used with a variable success rate and a residual shunt. Recently, specially designed Amplatzer muscular VSD occluder and Sideris device are in use. The Amplatzer muscular VSD occluder has been undergoing clinical trial since 1998 after the animal experiments had shown 100% occlusion and complete endothelization at 3 months. The procedure was first attempted in August 1995 using the Rashkind umbrella device and since April 1998 only the Amplatzer muscular VSD occluder has been used. Of the149 patients who underwent transcatheter closure of VSD, 50 had muscular trabecular defects in various locations: mid‐muscular, anterior, posterior, or apical. All cases were selected by detailed transthoracic and/or transesophageal echocardiography (TTE) and aneurysm of the muscular septum was observed in three of them. The age range was 3–28 years and the diameter of VSD was 4–11 mm. In all but one patient, the device was deployed from the venous side. Simultaneous TTE was done for proper positioning of the device and continuous electrocardiographic monitoring was also done for any arrhythmia/conduction defects. All patients were followed up every 3 months and received 3–5 mg/kg aspirin for 6 months. The procedure was successful in all patients. The Rashkind umbrella device (17 mm) was used in two and Amplatzer muscular VSD occluder (6–14 mm) in 48 patients. Forty‐four devices were delivered by antegrade transvenous approach and six by the transjugular route. None had residual shunt, new aortic regurgitation, or tricuspid regurgitation. Transient complete heart block after 24 hours was noticed in one patient. On a follow‐up of 2–90 months, the device was in position in all patients. There was no embolization of the device, and no late‐conduction defects, infective endocarditis, or hemolysis. Transcatheter closure of muscular VSD is safe and efficacious, and should be considered as a procedure of choice as an alternative to surgery that avoids cardiopulmonary bypass. (J Interven Cardiol 2004;17:109–115)
Transcatheter Atrial Septal Defect Closure Assisted by Intracardiac Echocardiography: 3‐Year Follow‐Up
Authors: ZANCHETTA MARIO , RIGATELLI GIANLUCA , PEDON LUIGI , ZENNARO MARCO , CARROZZA ANTONIO , ONORATO EUSTAQUIO , MAIOLINO PIETRO
Published: April 2004

Intracardiac echocardiographic (ICE) evaluation of secundum atrial septal defect (ASDs) shows several advantages over transesophageal echocardiography (TEE). The aim of our study is to describe the 3‐year results of transcatheter ASDs closure using the Amplatzer septal occluder (ASO) and ICE as the sole imaging tool both to select the device size and to monitor the procedure. Under local anesthesia, 135 consecutive eligible patients with ASDs (male/female = 45/90; mean age 42.2 ± 19.2 years; BSA 1.71 ± 0.7 m2; mean pulmonary arterial pressure 30.4 ± 11.5 mmHg; mean Qp/Qs ratio 2.1 ± 0.6) underwent transcatheter closure using ASO and ICE. A 9F‐9MHz mechanical transducer was used. Two orthogonal views on the transverse aortic valve and on the longitudinal four‐chamber planes were obtained for quantitative ICE measurements, from which the diameters of the implanting ASO waist were to be derived. In all cases, we obtained a proper evaluation of ICE ASDs dimensions, leading to an optimal device size selection (mean size 25.0 ± 6.7 mm). Moreover, the ICE allowed us to monitor device deployment and to verify the effectiveness of the ASDs stented by ASO. There were no complications related to the procedure or to the use of ICE. During a mean follow‐up period of 21.5 ± 12 months, the cumulative complete occlusion rates were 97.7, 97.0, 97.1, and 98% at 24 hours, 3 month, and 1 and 3 years, respectively. ICE is an effective and safe alternative to TEE and balloon‐sizing maneuver during ASDs transcatheter closure procedures, allowing us to avoid the need of general anesthesia and leading to a similarly high percentage of occlusion rates with respect to the conventional method. (J Interven Cardiol 2004;17:95–98)
Population-Level HIV Declines and Behavioral Risk Avoidance in Uganda
Authors: Stoneburner Rand L. , Low-Beer Daniel
Published: April 2004

Uganda provides the clearest example that human immunodeficiency virus (HIV) is preventable if populations are mobilized to avoid risk. Despite limited resources, Uganda has shown a 70% decline in HIV prevalence since the early 1990s, linked to a 60% reduction in casual sex. The response in Uganda appears to be distinctively associated with communication about acquired immunodeficiency syndrome (AIDS) through social networks. Despite substantial condom use and promotion of biomedical approaches, other African countries have shown neither similar behavioral responses nor HIV prevalence declines of the same scale. The Ugandan success is equivalent to a vaccine of 80% effectiveness. Its replication will require changes in global HIV/AIDS intervention policies and their evaluation.
Synaptic Changes in Layer 2/3 Underlying Map Plasticity of Developing Barrel Cortex
Authors: Petersen Carl C. H. , Brecht Michael , Hahn Thomas T. G. , Sakmann Bert
Published: April 2004

The functional and anatomical rearrangements of cortical sensory maps accompanying changes in experience are not well understood. We examined in vivo and in vitro how the sensory map and underlying synaptic connectivity of the developing rat barrel cortex are altered when the sensory input to the cortex is partially deprived. In the nondeprived cortex, both the sensory responses and synaptic connectivity between columns were strengthened through an increase in the synaptic connection probability between L2/3 pyramids in adjacent columns. This was accompanied by a selective growth of L2/3pyramid axonal arbors between spared columns. In contrast, deprived and nondeprived cortical columns became weakly connected in their L2/3 pyramid connections.
A History Recorded in the Margins
Authors: Barker Peter
Published: April 2004

The Book Nobody Read
Chasing the Revolutions of Nicolaus Copernicus. by Owen Gingerich. Walker, New York, 2004. 320 pp. $25, C$38.95. ISBN 0-8027-1415-3.

Gingerich describes the reception accorded Copernicus's
De revolutionibus
and his own adventures chasing extant copies and examining them for annotations and marginalia in order to refute Arthur Koestler's claim that the book was essentially unread.
CORRELATION ENERGIES IN TWO-ELECTRON IONS
Authors: MATTIS DANIEL C. , WU JIANSHENG , FU ZIWEN
Published: April 2004

We estimate the relative radial and angular correlation energies in the ground state of two-electron ions, such as in the hydrogen negative ion, the helium atom and the lithium positive ion, and find they are roughly equal.
RANDOM SEQUENTIAL ADSORPTION OF MIXTURES OF DIMERS AND MONOMERS ON A PRE-TREATED BETHE LATTICE
Authors: CADILHE ANTÓNIO , PRIVMAN VLADIMIR
Published: April 2004

We report studies of random sequential adsorption on the pre-patterned Bethe lattice. We consider a partially covered Bethe lattice, on which monomers and dimers deposit competitively. Analytical solutions are obtained and discussed in the context of recent efforts to use pre-patterning as a tool to improve self-assembly in micro- and nano-scale surface structure engineering.
SEMI-CLASSICAL SIMULATION OF ATOMIC DEPOSITION IN A STANDING WAVE LASER FIELD
Authors: CHEN XIANZHONG , YAO HANMIN , CHEN XUNAN , ZHANG CHUNMEI
Published: April 2004

An atom lens generated by a near-resonant light standing wave can be used to produce nanometer-scale structures. Our calculations are based on a Monte Carlo scheme and the trajectory tracing method. The influences of optical potential and source imperfection such as velocity spread and beam spread on the shape of chromium feature are analyzed using this approach. Results have shown that the focus depth for real source is longer than that for perfect source. Feature separation can be reduced by changing the detuning of the standing wave laser field from blue to red halfway through the deposition time.
NUMERICAL MODELING OF TWO-PHASE FLOWS USING THE TWO-FLUID TWO-PRESSURE APPROACH
Authors: GALLOUËT THIERRY , HÉRARD JEAN-MARC , SEGUIN NICOLAS
Published: April 2004

The present paper is devoted to the computation of two-phase flows using the two-fluid approach. The overall model is hyperbolic and has no conservative form. No instantaneous local equilibrium between phases is assumed, which results in a two-velocity two-pressure model. Original closure laws for interfacial velocity and interfacial pressure are proposed. These closures allow to deal with discontinuous solutions such as shock waves and contact discontinuities without ambiguity with the definition of Rankine–Hugoniot jump relations. Each field of the convective system is investigated, providing maximum principle for the volume fraction and the positivity of densities and internal energies are ensured when focusing on the Riemann problem. Two-finite volume methods are presented, based on the Rusanov scheme and on an approximate Godunov scheme. Relaxation terms are taken into account using a fractional step method. Eventually, numerical tests illustrate the ability of both methods to compute two-phase flows.
ASYMPTOTIC METHODS FOR MICROPOLAR FLUIDS IN A TUBE STRUCTURE
Authors: DUPUY D. , PANASENKO G. P. , STAVRE R.
Published: April 2004

The steady motion of a micropolar fluid through a wavy tube with the dimensions depending on a small parameter is studied. An asymptotic expansion is proposed and error estimates are proved by using a boundary layer method. We apply the method of partial asymptotic decomposition of domain and we prove that the solution of the partially decomposed problem represents a good approximation for the solution of the considered problem.
ANALYSIS OF A SPHERICAL HARMONICS EXPANSION MODEL OF PLASMA PHYSICS
Authors: HANSEN OLAF , JÜNGEL ANSGAR
Published: April 2004

A spherical harmonics expansion model arising in plasma and semiconductor physics is analyzed. The model describes the distribution of particles in the position-energy space subject to a (given) electric potential and consists of a parabolic degenerate equation. The existence and uniqueness of global-in-time solutions is shown by semigroup theory if the particles are moving in a one-dimensional interval with Dirichlet boundary conditions. The degeneracy allows to show that there is no transport of particles across the boundary corresponding to zero energy. Furthermore, under certain conditions on the potential, it is proved that the solution converges in the long-time limit exponentially fast to some steady state.
MODELLING OF OSCILLATIONS, BREAKUP AND COLLISIONS FOR DROPLETS: THE ESTABLISHMENT OF KERNELS FOR THE T.A.B. MODEL
Authors: BARANGER C.
Published: April 2004

In this work, we consider a spray consisting of droplets surrounded by a gas. The droplets are described by a kinetic equation and the gas verifies an equation of fluid dynamics such as Navier–Stokes. We write down the kernels corresponding to complex phenomena such as oscillations, breakup and collisions/coalescences. We use for that the T.A.B. model of oscillations introduced in particular in the KIVA code of combustion of Los Alamos, and the collision model introduced by Villedieu. We briefly explain the numerical method for solving such equations, and present results.
NATURALLY OCCURRING GENETIC VARIATION IN ARABIDOPSIS THALIANA
Authors: Koornneef Maarten , Alonso-Blanco Carlos , Vreugdenhil Dick
Published: April 2004

▪ Abstract  Currently, genetic variation is probably the most important basic resource for plant biology. In addition to the variation artificially generated by mutants in model plants, naturally occurring genetic variation is extensively found for most species, including Arabidopsis. In many cases, natural variation present among accessions is multigenic, which has historically hampered its analysis. However, the exploitation of this resource down to the molecular level has now become feasible, especially in model species like Arabidopsis, where several genes accounting for natural variation have already been identified. Dissecting this variation requires first a quantitative trait locus (QTL) analysis, which in Arabidopsis has proven very effective by using recombinant inbred lines (RILs). Second, identifying the particular gene and the nucleotide polymorphism underlying QTL is the major challenge, and is now feasible by combining high-throughput genetics and functional genomic strategies. The analysis of Arabidopsis natural genetic variation is providing unique knowledge from functional, ecological, and evolutionary perspectives. This is illustrated by reviewing current research in two different biological fields: flowering time and plant growth. The analysis of Arabidopsis natural variation for flowering time revealed the identity of several genes, some of which correspond to genes with previously unknown function. In addition, for many other traits such as those related to primary metabolism and plant growth, Arabidopsis QTL analyses are detecting loci with small effects that are not easily amenable by mutant approaches, and which might provide new insights into the networks of gene regulation.
PHOSPHOENOLPYRUVATE CARBOXYLASE: A New Era of Structural Biology
Authors: Izui Katsura , Matsumura Hiroyoshi , Furumoto Tsuyoshi , Kai Yasushi
Published: April 2004

▪ Abstract  There have been remarkable advances in our knowledge of this important enzyme in the last decade. This review focuses on three recent topics: the three-dimensional structure of the protein, molecular mechanisms of catalytic and regulatory functions, and the molecular cloning and characterization of PEPC kinases, which are Ser/Thr kinases involved specifically in regulatory phosphorylation of vascular plant PEPC. Analysis by X-ray crystallography and site-directed mutagenesis for E. coli and maize PEPC identified the catalytic site and allosteric effector binding sites, and revealed the functional importance of mobile loops. We present the reaction mechanism of PEPC in which we assign the roles of individual amino acid residues. We discuss the unique molecular property of PEPC kinase and its possible regulation at the post-translational level.
DECODING Ca2+ SIGNALS THROUGH PLANT PROTEIN KINASES
Authors: Harper Jeffrey F. , Breton Ghislain , Harmon Alice
Published: April 2004

▪ Abstract  Plants harbor four families of kinases that have been implicated in Ca2+ signaling (CDPKs, CRKs, CCaMKs, and SnRK3s). Although each family appears to respond to Ca2+ via different mechanisms, they all utilize Ca2+ sensors that bind Ca2+ through multiple EF-hands. The CDPK (Ca2+-dependent protein kinase) family is represented by the most genes, with 12 subfamilies comprised of 34 isoforms in Arabidopsis and 27 in rice. Some of the calcium-regulated kinases also show potential for regulation by lipid signals and kinase cascades. Thus, Ca2+-regulated kinases provide potential nodes of cross-talk for multiple signaling pathways that integrate Ca2+ signals into all aspects of plant growth and development.
METABOLIC CHANNELING IN PLANTS
Authors: Winkel Brenda S.J.
Published: April 2004

▪ Abstract  The organization of cooperating enzymes into macromolecular complexes is a central feature of cellular metabolism. A major advantage of such spatial organization is the transfer of biosynthetic intermediates between catalytic sites without diffusion into the bulk phase of the cell. This so-called “metabolic channeling” offers unique opportunities for enhancing and regulating cellular biochemistry. Studies in a number of plant primary and secondary metabolic systems continue to contribute to our understanding of the nature and importance of this phenomenon. This article reviews advances in four systems: the cysteine synthase complex, the Calvin cycle, cyanogenic glucoside biosynthesis, and the phenylpropanoid pathway. Each of these systems is providing new evidence for the importance of enzyme organization in cellular biochemistry as well as exclusive insights into the molecular basis of enzyme complex assembly. This review also explores current prospects for understanding metabolon structure, assembly, and biological function.
ALTERNATIVE NAD(P)H DEHYDROGENASES OF PLANT MITOCHONDRIA
Authors: Rasmusson Allan G. , Soole Kathleen L. , Elthon Thomas E.
Published: April 2004

▪ Abstract  Plant mitochondria have a highly branched electron transport chain that provides great flexibility for oxidation of cytosolic and matrix NAD(P)H. In addition to the universal electron transport chain found in many organisms, plants have alternative NAD(P)H dehydrogenases in the first part of the chain and a second oxidase, the alternative oxidase, in the latter part. The alternative activities are nonproton pumping and allow for NAD(P)H oxidation with varying levels of energy conservation. This provides a mechanism for plants to, for example, remove excess reducing power and balance the redox poise of the cell. This review presents our current understanding of the alternative NAD(P)H dehydrogenases present in plant mitochondria.
SINGLE-CELL C4 PHOTOSYNTHESIS VERSUS THE DUAL-CELL (KRANZ) PARADIGM
Authors: Edwards Gerald E. , Franceschi Vincent R. , Voznesenskaya Elena V.
Published: April 2004

▪ Abstract  The efficiency of photosynthetic carbon assimilation in higher plants faces significant limitations due to the oxygenase activity of the enzyme Rubisco, particularly under warmer temperatures or water stress. A drop in atmospheric CO2 and rise in O2 as early as 300 mya provided selective pressure for the evolution of mechanisms to concentrate CO2 around Rubisco in order to minimize oxygenase activity and the resultant loss of carbon through photorespiration. It is well established that a carbon-concentrating mechanism occurs in some terrestrial plants through the process of C4 photosynthesis. These plants are characterized as having Kranz-type leaf anatomy, with two structurally and biochemically specialized photosynthetic cell types, mesophyll and bundle sheath, that function coordinately in carbon assimilation. C4 photosynthesis has evolved independently many times with great diversity in forms of Kranz anatomy, structure of dimorphic chloroplasts, and biochemistry of the C4 cycle. The most dramatic variants of C4 terrestrial plants were discovered recently in two species, Bienertia cycloptera and Borszczowia aralocaspica (family Chenopodiaceae); each has novel compartmentation to accomplish C4 photosynthesis within a single chlorenchyma cell. This review discusses the amazing diversity in C4 systems, how the essential features of C4 are accomplished in single-cell versus Kranz-type C4 plants, and speculates on why single-cell C4 plants evolved.
MOLECULAR MECHANISM OF GIBBERELLIN SIGNALING IN PLANTS
Authors: Sun Tai-ping , Gubler Frank
Published: April 2004

▪ Abstract  The hormone gibberellin (GA) plays an important role in modulating diverse processes throughout plant development. In recent years, significant progress has been made in the identification of upstream GA signaling components and trans- and cis-acting factors that regulate downstream GA-responsive genes in higher plants. GA appears to derepress its signaling pathway by inducing proteolysis of GA signaling repressors (the DELLA proteins). Recent evidence indicates that the DELLA proteins are targeted for degradation by an E3 ubiquitin ligase SCF complex through the ubiquitin-26S proteasome pathway.
VIGS VECTORS FOR GENE SILENCING: Many Targets, Many Tools
Authors: Robertson Dominique
Published: April 2004

▪ Abstract  The discovery that plants recognize and degrade invading viral RNA caused a paradigm shift in our understanding of viral/host interactions. Combined with the discovery that plants cosuppress their own genes if they are transformed with homologous transgenes, new models for both plant intercellular communication and viral defense have emerged. Plant biologists adapted homology-based defense mechanisms triggered by incoming viruses to target individual genes for silencing in a process called virus-induced gene silencing (VIGS). Both VIGS- and dsRNA-containing transformation cassettes are increasingly being used for reverse genetics as part of an integrated approach to determining gene function. Virus-derived vectors silence gene expression without transformation and selection. However, because viruses also alter gene expression in their host, the process of VIGS must be understood. This review examines how DNA and RNA viruses have been modified to silence plant gene expression. I discuss advantages and disadvantages of VIGS in determining gene function and guidelines for the safe use of viral vectors.
VISUALIZING CHROMOSOME STRUCTURE/ORGANIZATION
Authors: Lam Eric , Kato Naohiro , Watanabe Koichi
Published: April 2004

▪ Abstract  With the rapid development of sequencing technologies in the past decade, many eukaryotic genomes have been resolved at the primary sequence level. However, organization of the genome within nuclei and the principles that govern such properties remain largely unclear. Optimization of fluorescence probe-based hybridization technologies combined with new advances in the instrumentation for microscopy has steadily yielded more structural information on chromosome organization in eukaryote model systems. These studies provide static snapshots of the detailed organization of chromatin. More recently, the successful application of a chromatin tagging strategy utilizing auto fluorescent fusion proteins opened a new era of chromatin studies in which the dynamic organization of the genome can be tracked in near real time. This review focuses on these new approaches to studying chromatin organization and dynamics in plants, and on future prospects in unraveling the basic principle of chromosome organization.
SINGLE-MOLECULE OPTICS
Authors: Kulzer Florian , Orrit Michel
Published: April 2004

▪ Abstract  We review recent developments in single-molecule spectroscopy and microscopy. New optical methods provide access to the absorption, emission, or excitation spectra of single nano-objects and can determine either the positions of these objects with subwavelength accuracy or the full three-dimensional orientation of their transition dipole moments. Recent work aims at using single molecules as nanoparts or nanoelements in a variety of molecular-scale devices, from triggered sources of single photons to single-molecular switches. A prominent new direction explores the various interactions between molecules within individual multichromophoric systems obtained by chemical synthesis. These systems are the models for natural self-assembled systems such as the light-harvesting proteins of bacteria and green plants, which are currently studied on a single-molecule basis. Another important class of multichromophoric systems are conjugated polymers. The combination of microscopy with time- and frequency-resolved spectroscopy is opening a wide field of new and exciting applications to individual nano-objects.
DYNAMICS OF SINGLE BIOMOLECULES IN FREE SOLUTION
Authors: Yeung Edward S.
Published: April 2004

▪ Abstract  Instrumental advances have allowed the continuous observation of single-molecule trajectories in free solution. Diffraction-limited spectral resolution at video frame rates is routinely achieved by using commercial, intensified, charge-coupled device cameras, low-power continuous-wave lasers, and standard optical microscopes. Either the native fluorescence from large biomolecules or emission from conjugated fluorescence labels can be employed to follow multiple molecules over many seconds. Both molecular motion at the liquid/solid interface and in bulk solution can be recorded. The former reveals adsorption and desorption probabilities that are related to chromatographic retention processes and to the applicability of biocompatible materials. The latter allows the manipulation of particles and large biomolecules to facilitate separation and identification.
BIOMIMETIC NANOSCALE REACTORS AND NETWORKS
Authors: Karlsson Mattias , Davidson Max , Karlsson Roger , Karlsson Anders , Bergenholtz Johan , Konkoli Zoran , Jesorka Aldo , Lobovkina Tatsiana , Hurtig Johan , Voinova Marina , Orwar Owe
Published: April 2004

▪ Abstract  Methods based on self-assembly, self-organization, and forced shape transformations to form synthetic or semisynthetic enclosed lipid bilayer structures with several properties similar to biological nanocompartments are reviewed. The procedures offer unconventional micro- and nanofabrication routes to yield complex soft-matter devices for a variety of applications for example, in physical chemistry and nanotechnology. In particular, we describe novel micromanipulation methods for producing fluid-state lipid bilayer networks of nanotubes and surface-immobilized vesicles with controlled geometry, topology, membrane composition, and interior contents. Mass transport in nanotubes and materials exchange, for example, between conjugated containers, can be controlled by creating a surface tension gradient that gives rise to a moving boundary or by induced shape transformations. The network devices can operate with extremely small volume elements and low mass, to the limit of single molecules and particles at a length scale where a continuum mechanics approximation may break down. Thus, we also describe some concepts of anomalous fluctuation-dominated kinetics and anomalous diffusive behaviours, including hindered transport, as they might become important in studying chemistry and transport phenomena in these confined systems. The networks are suitable for initiating and controlling chemical reactions in confined biomimetic compartments for rationalizing, for example, enzyme behaviors, as well as for applications in nanofluidics, bioanalytical devices, and to construct computational and complex sensor systems with operations building on chemical kinetics, coupled reactions and controlled mass transport.
OPTICALLY DETECTED MAGNETIC RESONANCE STUDIES OF COLLOIDAL SEMICONDUCTOR NANOCRYSTALS
Authors: Lifshitz E. , Fradkin L. , Glozman A. , Langof L.
Published: April 2004

▪ Abstract  The review describes the studies of the magneto-optical properties of II-VI and III-V semiconductor nanocrystals (NCs) capped with organic or inorganic epitaxial shells. The investigations focused on the chemical identification of localization sites (core, shell, or interface) of photogenerated carriers in spherical NCs and elucidated the influence of the surface/interface quality on the optical properties of the materials. Optically detected magnetic resonance (ODMR) spectroscopy was used for the study of the proposed physical properties. The ODMR method provides the means to identify the surface/interface sites and correlate them with specific optical transition. In addition, this method reveals information about the spin multiplicity of band edge and trapped states and the electron-hole exchange interaction, determines the spectroscopic g-factors, distinguishes between the radiative and nonradiative characteristic of a trapping site, and evaluates the spin-lattice relaxation times.
FUNCTIONAL OXIDE NANOBELTS: Materials, Properties and Potential Applications in Nanosystems and Biotechnology
Authors: Wang Zhong Lin
Published: April 2004

▪ Abstract  Nanobelt is a quasi-one-dimensional structurally controlled nanomaterial that has well-defined chemical composition, crystallographic structure, and surfaces (e.g., growth direction, top/bottom surface, and side surfaces). This article reviews the nanobelt family of functional oxides, including ZnO, SnO2, In2O3, Ga2O3, CdO, and PbO2and the relevant hierarchical and complex nanorods and nanowires that have been synthesized by a solid-vapor process. The nanobelts are single crystalline and dislocation free, and their surfaces are atomically flat. The oxides are semiconductors that have been used for fabrication of nanosize functional devices of key importance for nanosystems and biotechnology, such as field-effect transistors, gas sensors, nanoresonators, and nanocantilevers.

The structurally controlled ZnO nanobelts that exhibit piezoelectric properties are also reviewed. By controlling growth kinetics, we show the success of growing nanobelt-based novel structures whose surfaces are dominated by the polarized ±(0001) facets. Owing to the positive and negative ionic charges on the zinc- and oxygen-terminated ±(0001) surfaces, respectively, a spontaneous polarization is induced across the nanobelt thickness. As a result, helical nanostructures and nanorings are formed by rolling up single-crystal nanobelts; this phenomenon is a consequence of minimizing the total energy contributed by spontaneous polarization and elasticity. The polar surface–dominated ZnO nanobelts are likely to be an ideal system for understanding piezoelectricity and polarization-induced ferroelectricity at nano-scale and they could have applications as one-dimensional nano-scale sensors, transducers, and resonators.
“To Resolve the Ukrainian Problem Once and for All”: The Ethnic Cleansing of Ukrainians in Poland, 1943–1947
Authors: Snyder Timothy
Published: April 2004

The complicated and violent interactions between Ukrainians and Poles during and after World War II have been the subject of competing Ukrainian and Polish historical interpretations. This article sifts through the historical evidence to determine why Ukrainian and Polish memories of that period are so much at odds. The fate of the contested territories of Eastern Galicia and Volhynia was decided ultimately by the Soviet Union, which imposed new borders on Poland. Once those borders had been established, the transfer of Poles from the newly enlarged Soviet Ukraine and the forced removal of Ukrainians from eastern Poland consolidated an “ethnically cleansed” post-war order.
Distribution and Abundance of Phyllosoma Larvae (Decapoda, Palinuridae) in the Southern Gulf of Mexico and the Western Caribbean Sea
Authors: Gasca Rebeca , Manzanilla-Dominguez Heyden
Published: April 2004

From plankton samples collected during two oceanographic expeditions in the southern Gulf of Mexico (1991) and five in the Mexican Caribbean Sea, we studied the composition, abundance, and distribution of the phyllosoma larvae. A total of 118 phyllosomas belonging to five species of lobster were recorded. Panulirus argus was the most abundant and dominant, it represented 73.9% of the total number of phyllosomas collected, followed by Scyllarides aequinoctialis (18.0%). The phyllosomas were distributed mainly in the coastal areas, with decreasing densities oceanwards. Highest larval concentrations were recorded near the outer border of the Campeche Bank shelf in the southern Gulf of Mexico. In the Mexican Caribbean area, phyllosomas were most abundant around Banco Chinchorro, off Espiritu Santo Bay and Ascension Bay, and near Isla Mujeres; these are well-known spawning areas for the spiny lobster, P. argus and are indicated by the presence of the earliest larval stages. The oldest larvae were concentrated on the Campeche Bank; this was attributed to the effect of a local gyre that retains these larvae. The youngest phyllosomas tended to have an oceanic distribution thus allowing them to enter the oceanic system of mesoscale gyres of the Gulf. In the Mexican Caribbean the coastal shoreward currents seem to act as a retention system for lobster larvae. The distribution of the phyllosoma stages in the Caribbean area suggests a continuous presence of different stages year-round. Some of these larvae, in the northeastern sector, would likely be transported to the Campeche Bank.
Mate Choice in the Big-Clawed Snapping Shrimp, Alpheus Heterochaelis Say, 1818
Authors: Rahman Nasreen , Dunham David ,   Govind
Published: April 2004

In socially monogamous animals mate choice can be expected when mates vary in quality, degree of parental investment, or ability to defend an important resource. Mate choice was expected in the big-clawed snapping shrimp, Alpheus heterochaelis Say, 1818, as female size is positively correlated with fecundity. In addition, males and females share a shelter, which they defend from intruders, and therefore, resource holding potential could be an important component in mate choice. We tested the effect of body size and shelter ownership on mate choice and on competition in both sexes. As shelter occupancy and defence may have an influence on pair formation and mate choice, we also tested competitive success in obtaining preferred shelters as a variable in mate choice. We did not find evidence that males preferred larger females, but showed that females preferred and competed for larger males. Females paired more frequently with smaller males that occupied a shelter than with smaller males without a shelter. Males were, however, more successful in evicting smaller same-sex conspecifics from preferred shelters than females were. This could indicate that competition for shelter favours males with larger claws, and hence, body size, as these are better able to defend a shelter from other conspecifics. A female may therefore choose larger males, because she is dependent on both a male and a shelter for successful reproduction.
A Numerical Daily Air Quality Forecast System for The Pacific Northwest
Authors: Vaughan Joseph , Lamb Brian , Frei Chris , Wilson Rob , Bowman Clint , Figueroa-Kaminsky Cristiana , Otterson Sally , Boyer Mike , Mass Cliff , Albright Mark , Koenig Jane , Collingwood Alice , Gilroy Mike , Maykut Naydene
Published: April 2004

A real-time photochemical air quality forecast system has been implemented for the Puget Sound region to support public awareness of air quality issues. The Air Indicator Report for Public Access and Community Tracking (AIRPACT) forecast system uses daily numerical weather forecasts from the fifth-generation Pennsylvania State University (PSU)–National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) to drive the California Meteorological Model (CALMET)/California photochemistry grid model (CALGRID) Eulerian photochemical modeling suite. Hourly forecasts of ozone and other pollutant concentrations, including primary particulate emissions from diesel sources, are produced for urban Seattle and environs within a gridded domain consisting of 62 × 67 grid cells (4 km × 4 km) with 13 vertical layers. Detailed gridded emission inventories are adjusted dynamically for time of day, day of the week, month, and gridded ambient temperatures to generate requisite emissions. The forecast system also uses hourly pollutant observation data, reported daily, to perform automated evaluations of forecast accuracy. Forecasts and verification results are provided on a daily basis via the Web (see www.airpact.wsu.edu). This paper describes the forecast system and presents preliminary forecast evaluation results from the Pacific Northwest 2001 (PNW2001) field program and from selected months using the routine monitoring network. AIRPACT is unique nationally as the sole numerical modeling system producing daily, year-round, high-resolution regional air quality forecasts with daily verification.
Analysis of Land Skin Temperature Using AVHRR Observations
Authors: Jin Menglin
Published: April 2004

Using satellite remote sensing techniques to take quantitative observations of the climate system will advance our knowledge and ability to model the climate system and its changes. Polar-orbiting satellite records of global land surface skin temperature (LST) observations have high coverage and quality. Although limited in accuracy, and to a few years in length, these measurements are extremely useful because they are improvements on existing data.

This paper introduces a global, long-duration satellite diurnal cycle dataset of LST for 1981–98. LST measurements from National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) sensors are generally only twice per day for most areas and suffer problems such as cloud contamination and orbital drift. These problems are corrected using the algorithms developed by Jin and Dickinson, Jin, and Jin and Treadon, and consequently provide a long-term, monthly, global 8-km land surface skin temperature diurnal cycle dataset (LSTD) for temporally consistent LST records.

As a unique and independent resource, LSTD is valuable for studying the land surface climate and for evaluating model performance. For the first time, in this paper, the diurnal, seasonal, and interannual variations of LST are presented as a prototype use of this dataset. In addition, LSTD is compared with the National Centers for Environmental Prediction (NCEP)-National Center for Atmospheric Research (NCAR) reanalysis, in situ air temperature, the NOAA's Television Infrared Observation Satellite (TIROS) Operational Vertical Sounder (TOVS) observations, and shows encouraging consistencies on major features. These consistencies suggest that LSTD will be very valuable for climate change study.
Business, Economy, and the Environmet Toward a New Development Paradigm
Authors: Gendron Corinne
Published: April 2004

According to regulation theory, social actors are redefining economic institutional forms from which a newpostfordist development model could emerge. The fordist model, based on an industrialist development model and specific institutional forms regarding organization of production, the distribution of surplus value, and international integration, has been broken by the 1973 crisis and the globalization process. The new institutional forms are shaped by actors engaged in social conflicts who eventually compromise permitting a certain degree of order that allows social and economic action. The social representation of the representatives of the economic order will have a strong impact on the structure and content of that new compromise. Understanding the conceptual framework underlying business action is essential for anticipating the economic institutional forms presently emerging, especially those regarding environmental matters. Presented here are the results of research conducted among the top managers of Quebec businesses regarding their social representations on key topics of the economic order and the environment.
Evaluating the Use of a Psychiatric Intensive Care Unit: Is Ethnicity a Risk Factor for Admission?
Authors: Feinstein Anthony , Holloway Frank
Published: April 2004

Objective: This paper presents a descriptive study, undertaken in 1993, of a Psychiatric Intensive Care Unit (PICU) serving a deprived inner-city area, investigating the role of ethnicity as a risk factor for admission to the unit.

Methods: Clinical and demographic data were collected on consecutive admission to a PICU. Global Assessment of Function Scale scores were rated on admission and at discharge from the unit.

Results: The majority of patients were male (63%) and the commonest DSM-IV diagnoses were schizophrenia (42%) and bipolar affective disorder (24%). Average length of stay was 13 days with patients making significant improvement in functioning during their stay. Fifty-five percent of PICU admissions came from ethnic minorities (compared with 25.6% of total hospital admissions and 20.9% of the local catchment area population aged between 16 and 65 years). There was no evidence that ethnic minority patients were being inappropriately admitted to the PICU.

Conclusions: It is likely that a variety of factors contributed to the high rate of PICU admission amongst ethnic minority patients, including an increased prevalence of major mental illness and more frequent cannabis abuse.
Effect of Culture and Environment on the Phenomenology of Delusions and Hallucinations
Authors: Suhail Kausar , Cochrane Raymond
Published: April 2004

Background: The present study was conducted to compare the influence of culture and immediate environment on the phenomenology of schizophrenic symptoms by examining the actual content of delusions and hallucinations in three groups of schizophrenic patients.

Method: Pakistanis living in Britain (BP; N = 53), Pakistanis in Pakistan (PP; N = 98) and British White (BW; N = 50). The content of the patients' delusions and hallucinations was obtained from medical records and key-workers' reports from All-Saints Hospital, Birmingham and two psychiatric units in Lahore. All references to delusions and hallucinations were coded in accordance with the classification scheme developed for the Present State Examination (Wing et al., 1974).

Results: Comparisons indicated greater differences in phenomenology of delusions and hallucinations between the Pakistani pair (BP vs. PP) than between the British groups (BP vs. BW). The findings suggested a stronger influence of the immediate environment on the pathogenesis of delusions and hallucinations.

Conclusions: The results are discussed with reference to the cultural and religious values of the ethnic groups.