bluuebunny/crossref_metadata_2025 huggingface dataset:
Detecting Specific Patterns of Change for Two Outcome Scores in a Mental Health Study by Means of Linear Mixture Models
Authors: Matschinger Herbert , Kilian Reinhold , Angermeyer Matthias C.
Published: July 2006

Common practice evaluates the success of any form of (medical) treatment by evaluating the change and the relation of change for particular outcome criteria. However, we must assume that the expected change over time can only be observed for—perhaps only small—subgroups. The purpose of this article, therefore, is to explain and demonstrate a method on how to measure the relationships of change for important outcomes in a longitudinal study of schizophrenia treatment and to identify latent subgroups of patients characterized by different shapes of trajectories and relations of trajectories. We will focus on the change over time for the Social and Occupational F unctioning A ssessment S core (SOFAS) (American Psychiatric Association, 1987) and the subjective health-related quality of life assessed by SF-36 (Ware, Gandek, & The IQOLA Project Group, 1994) . The sample employed for this study consists of 307 patients with a diagnosis of schizophrenia (ICD-10 F20.0) treated by psychiatric services in Leipzig. The method adopted to portray these changes is the growth mixture model, which combines latent class analysis with the approach of modeling individual trajectories. Results show that a positive relation between the outcomes of interest can only be observed for about 15% of the sample.
Does Money Matter? A Theory-Driven Growth Mixture Model to Explain Travel-Mode Choice with Experimental Data
Authors: Davidov Eldad , Yang-Hansen Kajsa , Gustafsson Jan-Eric , Schmidt Peter , Bamberg Sebastian
Published: July 2006

In the present article we apply a growth mixture model using Mplus via STREAMS to delineate the mechanism underlying travel-mode choice. Three waves of an experimental field study conducted in Frankfurt Main, Germany, are applied for the statistical analysis. Five major questions are addressed: (1) whether the choice of public transport rather than the car changes over time; (2) whether a soft policy intervention to change travel mode choice has any effect on the travel-mode chosen; (3) whether one can identify different groups of people regarding the importance allocated to monetary and time considerations for the decision of which travel mode to use; (4) whether the different subgroups of people have different initial states and rates of change in their travel-model choices; (5) whether sociodemographic variables have an additional effect on the latent class variables and on the changes in travel-mode choice over time. We also found that choice of public transportation in our study is stable over time. Moreover, the intervention has an effect only on one of the classes. We identify four classes of individuals. One class allocates a low importance to both monetary and time considerations, the second allocates high importance to money and low importance to time, the third allocates high importance to both, and the fourth allocates a low importance to money and a high importance to time. We found no difference in the patterns of travel-mode changes over time in the four classes. We also found some additional effects of sociodemographic characteristics on the latent class variables and on behavior in the different classes. The model specification and the empirical findings are discussed in light of the theory of the allocation of time of Gary Becker.
Recent left‐oblique slip faulting in the central eastern Trans‐Mexican Volcanic Belt: Seismic hazard and geodynamic implications
Authors: Norini G. , Groppelli G. , Lagmay A. M. F. , Capra L.
Published: July 2006

Detailed structural analysis was conducted on the E‐W trending Tenango Fault System (TFS) at the western end of the La Pera Fault System, a major structure within the Trans‐Mexican Volcanic Belt (TMVB). Field mapping, which included trenching the fault trace, revealed the displacement of recent volcanic deposits. The study indicates that the TFS is an active subvertical fault with transtensive left‐lateral movement consistent with the contemporary stress regime in the region. The estimated Holocene slip rate is 0.3–0.5 mm/yr. The TFS activity constitutes an important seismic hazard in the intra‐arc Lerma basin. Several towns are located within this basin and are particularly vulnerable to seismic risk because of its underlying strata consisting of lacustrine and volcaniclastic deposits (estimated maximum Mw 6.8–7). The TFS is an important structural element in the complex tectonic deformation history of central eastern TMVB and influenced the behavior of recent volcanism within the Lerma basin.
The convergence of complete active space self-consistent-field configuration interaction including all single and double excitation energies to the complete basis set limit
Authors: Petersson George A. , Malick David K. , Frisch Michael J. , Braunstein Matthew
Published: July 2006

Examination of the convergence of full valence complete active space self-consistent-field configuration interaction including all single and double excitation (CASSCF-CISD) energies with expansion of the one-electron basis set reveals a pattern very similar to the convergence of single determinant energies. Calculations on the lowest four singlet states and the lowest four triplet states of N2 with the sequence of n-tuple-ζ augmented polarized (nZaP) basis sets (n=2, 3, 4, 5, and 6) are used to establish the complete basis set limits. Full configuration-interaction (CI) and core electron contributions must be included for very accurate potential energy surfaces. However, a simple extrapolation scheme that has no adjustable parameters and requires nothing more demanding than CAS(10e−,8orb)-CISD/3ZaP calculations gives the Re, ωe, ωeXe, Te, and De for these eight states with rms errors of 0.0006Å, 4.43cm−1, 0.35cm−1, 0.063eV, and 0.018eV, respectively.
Basis-set extrapolation techniques for the accurate calculation of molecular equilibrium geometries using coupled-cluster theory
Authors: Heckert Miriam , Kállay Mihály , Tew David P. , Klopper Wim , Gauss Jürgen
Published: July 2006

To reduce remaining basis-set errors in the determination of molecular equilibrium geometries, a basis-set extrapolation (BSE) scheme is suggested for the forces used in geometry optimizations. The proposed BSE scheme is based on separating the Hartree-Fock and electron-correlation contributions and uses expressions obtained by straightforward differentiation of well established extrapolation formulas for energies when using basis sets from Dunning’s hierarchy of correlation-consistent basis sets. Comparison with reference data obtained at the R12 coupled-cluster level [CCSD(T)-R12] demonstrates that BSE significantly accelerates the convergence to the basis-set limit, thus leading to improvements comparable to or even better than those obtained by increasing the cardinal number in the used basis set by one. However, BSE alone is insufficient to improve agreement with experiment, even after additional consideration of inner-shell correlation and quadruple-excitation effects (mean error and standard deviation with extrapolation are −0.014 and 0.047pm in comparison with mean error and standard deviation of −0.002 and 0.036pm without extrapolation). Improvement is obtained only when other contributions of similar magnitude as the BSE contributions (e.g., pentuple-excitation effects and relativistic effects) are also considered. A rather large discrepancy (of the order of a few tenths of a picometer) is observed for the F2 molecule indicating an enhanced basis-set requirement for the various contributions in this case.
Layer-by-layer growth of thin amorphous solid water films on Pt(111) and Pd(111)
Authors: Kimmel Greg A. , Petrik Nikolay G. , Dohnálek Zdenek , Kay Bruce D.
Published: July 2006

The growth of amorphous solid water (ASW) films on Pt(111) is investigated using rare gas (e.g., Kr) physisorption. Temperature programmed desorption of Kr is sensitive to the structure of thin water films and can be used to assess the growth modes of these films. At all temperatures that are experimentally accessible (20–155K), the first layer of water wets Pt(111). Over a wide temperature range (20–120K), ASW films wet the substrate and grow approximately layer by layer for at least the first three layers. In contrast to the ASW films, crystalline ice films do not wet the water monolayer on Pt(111). Virtually identical results were obtained for ASW films on epitaxial Pd(111) films grown on Pt(111). The desorption rates of thin ASW and crystalline ice films suggest that the relative free energies of the films are responsible for the different growth modes. However, at low temperatures, surface relaxation or “transient mobility” is primarily responsible for the relative smoothness of the films. A simple model of the surface relaxation semiquantitatively accounts for the observations.
Ultrafast fluorescence resonance energy transfer in a micelle
Authors: Sahu Kalyanasis , Ghosh Subhadip , Mondal Sudip Kumar , Ghosh Bankim Chandra , Sen Pratik , Roy Durba , Bhattacharyya Kankan
Published: July 2006

Ultrafast fluorescence resonance energy transfer (FRET) from coumarin 153 (C153) to rhodamine 6G (R6G) is studied in a neutral PEO20–PPO70–PEO20 triblock copolymer (P123) micelle and an anionic micelle (sodium dodecyl sulfate, SDS) using a femtosecond up-conversion setup. Time constants of FRET were determined from the rise time of the acceptor emission. It is shown that a micelle increases efficiency of FRET by holding the donor and the acceptor at a close distance (intramicellar FRET) and also by tuning the donor and acceptor energies. It is demonstrated that in the P123 micelle, intramicellar FRET (i.e., donor and acceptor in same micelle) occurs in 1.2 and 24ps. In SDS micelle, there are two ultrafast components (0.7 and 13ps) corresponding to intramicellar FRET. The role of diffusion is found to be minor in the ultrafast components of FRET. We also detected a much longer component (1000ps) for intramicellar FRET in the larger P123 micelle.
Strong electric field and nonuniformity effects in GaN∕AlN quantum dots revealed by high pressure studies
Authors: Teisseyre H. , Suski T. , Łepkowski S. P. , Perlin P. , Jurczak G. , Dłużewski P. , Daudin B. , Grandjean N.
Published: August 2006

The photoluminescence (PL) from GaN quantum dots (QDs) embedded in AlN has been investigated under hydrostatic pressure. The measured pressure coefficient of emitted light energy [dEE∕dP] shows a negative value, in contrast with the positive pressure coefficient of the GaN band gap. We also observed that increasing pressure leads to a significant decrease of the light emission intensity and an asymmetric broadening of the PL band. All these effects are related to the pressure-induced increase of the built-in electric field. A comparison is made between experimental results and the proposed theoretical model which describes the pressure behavior of nitride QDs.
Relativistic electron distribution function of a plasma in a near-critical electric field
Authors: Sandquist P. , Sharapov S. E. , Helander P. , Lisak M.
Published: July 2006

A corrected relativistic collision operator is used to derive a Fokker-Planck equation for the distribution function of relativistic suprathermal electrons in a weakly relativistic plasma, which is then solved by a procedure similar to that employed in Connor and Hastie [Nucl. Fusion 15, 415 (1975)]. Analytical expressions are derived for the electron distribution function in plasmas with the electric field close to critical, which is typical of plasmas with grassy sawteeth on the Joint European Torus. A numerical solution is used for determining the normalization constant, which matches the relativistic region onto the weakly relativistic region. It is found that the scaling of the runaway rate with the electric field obtained by Connor and Hastie is a good approximation in spite of their use of an incomplete form of the collision operator not conserving number of particles. The present analysis determines the proportionality constant and introduces corrections to the earlier scaling of the runaway rate with respect to the electric field. The results obtained for the electron distribution function constitute a basis for studies of experimentally observed phenomena in near-threshold electric field plasmas with a significant suprathermal electron population.
Effect of nanocavity confinement on the rotational relaxation dynamics: 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine in micelles
Authors: Das Paramita , Mallick Arabinda , Chakrabarty Alok , Haldar Basudeb , Chattopadhyay Nitin
Published: July 2006

In continuation of our recent study on the steady state photophysics of a biologically active β-carboline derivative, 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine (AODIQ), in the present article we have investigated the effect of nanocavity confinement on the excited state dynamics and rotational relaxation of the probe using picosecond time resolved fluorescence and fluorescence anisotropy techniques. The polarity dependent intramolecular charge transfer process is responsible for the remarkable sensitivity of this biological fluorophore in micellar environments. The fluorescence anisotropy decay of AODIQ incorporated inside the micelle is biexponential. The rotational motion of the probe was interpreted on the basis of a two step model consisting of a fast restricted rotation of the probe and a slow lateral diffusion of the probe in the micelle; both coupled to the overall rotation of the micelle. Experimental results reveal that micellar environment causes significant retardation of both the wobbling as well as the translational motion of the probe.
Theoretical study of photodissociation dynamics on the lowest-lying Rydberg state of ketene
Authors: Liu Yang , Yu Jian-Kang , Huang Xu-Ri , Sun Chia-Chung
Published: July 2006

In the present study, an attempt is made to reveal the main mechanism of photodissociation on the lowest-lying Rydberg state B11 of ketene, referred to as the second singlet excited state S2, by means of the complete active space self-consistent field and the second-order multiconfigurational perturbation theory methods. The located S2∕S1∕T1 three-surface intersection plays an important role in the dissociation process. It is shown that the intersection permits an efficient internal conversion from S2 to S1 state, but prohibits the intersystem crossing from S2 to T1 state because of the small spin-orbital coupling value of 0.136cm−1. The main photodissociation process could be described as follows: after one photon absorption to the S2 state, ketene preferentially relaxes to the minimum S2̱C2v, and undergoes a transition state S2̱TS with small potential barrier along the Cs-I (out-of-plane bent) symmetry, and passes through the S2∕S1∕T1 intersection to reach S1 surface, then arrives at the transition state S1̱TS along the minimum energy path. As is well known, S1→S0 internal conversion around the Franck-Condon region is expected to be very efficient, and eventually the hot S0 molecule has accumulated enough energy to yield the CH2 (ãA11) and CO (X̃Σ+1) products.
Bone diagnostic instrument
Authors: Hansma Paul K. , Turner Patricia J. , Fantner Georg E.
Published: July 2006

The bone diagnostic instrument is designed to measure materials properties of bone even if it is covered with soft tissue such as periosteum, connective tissue and skin. It uses (1) a probe assembly, consisting of a reference probe that penetrates soft tissue and stops on the surface of the bone and a test probe that is inserted into the bone, (2) an actuation system that can move the test probe, typically into and out of the bone, (3) a sensing system that can determine the dynamics of the test probe as it moves in the bone, and (4) a measurement system to record the data that is sensed during the motion. In our current prototype, a sharpened, solid test probe slides inside a sharpened hypodermic syringe that serves as the reference probe. A load cell senses the force as a function of the distance that the test probe is inserted into the bone relative to the position of the reference probe that rests on the surface of the bone, measured with a linear variable displacement transformer. Examples of the type of data that can be taken with this prototype include cyclic force versus distance curves that show differences in material properties of different types of bone.
Surfactant adsorption at superhydrophobic surfaces
Authors: Ferrari Michele , Ravera Francesca , Rao Silvia , Liggieri Libero
Published: August 2006

Here the wetting of ionic and nonionic surfactant solutions on a superhydrophobic interface, obtained by using a mixed inorganic-organic coating providing a fractal-like structure, has been investigated to define the role of adsorption at these interfaces. The presence of the amphiphilic molecules is effective in lowering the contact angle in a hydrophobic or still superhydrophobic range. Influencing the adsorption properties by acting on the surfactant type and concentration, the spreading of a drop on the surface can be controlled by amphiphiles confining its volume in a restricted space.
Transition from Fowler-Nordheim field emission to space charge limited current density
Authors: Feng Y. , Verboncoeur J. P.
Published: July 2006

The Fowler-Nordheim law gives the current density extracted from a surface under strong fields, by treating the emission of electrons from a metal-vacuum interface in the presence of an electric field normal to the surface as a quantum mechanical tunneling process. Child’s law predicts the maximum transmitted current density by considering the space charge effect. When the electric field becomes high enough, the emitted current density will be limited by Child’s law. This work analyzes the transition of the transmitted current density from the Fowler-Nordheim law to Child’s law space charge limit using a one-dimensional particle-in-cell code. Also studied is the response of the emission model to strong electric fields near the transition point. We find the transition without geometrical effort is smooth and much slower than reported previously [J. P. Barbour, W. W. Dolan, J. K. Trolan, E. E. Martin, and W. P. Dyke, Phys. Rev. 92, 45 (1953)]. We analyze the effects of geometric field enhancement and work function on the transition. Using our previous model for effective field enhancement [Y. Feng and J. P. Verboncoeur, Phys. Plasmas 12, 103301 (2005)], we find the geometric effect dominates, and enhancement β>10 can accelerate the approach to the space charge limit at practical electric field. A damped oscillation near the local plasma frequency is observed in the transient system response.
High frequency fishbones excited by near perpendicular neutral beam injection
Authors: Zhou Deng
Published: July 2006

The high frequency fishbone instability observed in experiments with near perpendicular neutral beam injection is interpreted as the ideal internal kink mode destabilized by circulating energetic ions. The mode frequency is close to the transit frequency of circulating ions. The beta value of the circulating ions is required to peak on the magnetic axis and the average value within the q=1 magnetic surface must exceed a critical value for the mode to grow up.
Propagation and dual-localization of surface plasmon polaritons in a quasiperiodic metal heterowaveguide
Authors: Zhou Lin , Yu Xiao-qiang , Zhu Yong-yuan
Published: August 2006

Based on the transfer matrix method and the finite-difference time-domain analysis, we investigate the propagation and scattering of surface plasmon polaritons (SPPs) in a quasiperiodic metal heterowaveguide. By selecting appropriate thickness of the defect layer, the two SPP modes can be adjusted to localize at around 1310 and 1550nm simultaneously. The numerical results reveal that the realization of miniaturized photonic devices is feasible at the two important telecommunicate wavelengths. The structure can be applied to the double-band plasmon Bragg reflector, double-channel light emitters and filters.
Molecular identification of the primary root fungal endophytes of Dipodium hamiltonianum (Orchidaceae)
Authors: Dearnaley J. D. W. , Le Brocque A. F.
Published: August 2006

We have identified the primary root fungal endophytes of Dipodium hamiltonianum F.M.Bailey, a species of orchid endangered in Victoria and uncommon in New South Wales and Queensland. Genomic DNA was extracted from whole colonised root portions from four orchid individuals and PCR amplified with ITS1F and ITS4 primers. Cloning and sequencing of the main amplicons produced from the PCR analysis revealed that the primary root fungal endophytes were Gymnomyces and Russula spp., both members of the Russulaceae. The implications of these findings are discussed in terms of conservation of the orchid species.
Genetic supressors of Lotus japonicus har1-1 hypernodulation show altered interactions with Glomus intraradices
Authors: Murray Jeremy , Geil Ryan , Wagg Cameron , Karas Bogumil , Szczyglowski Krzysztof , Peterson R. Larry
Published: August 2006

Mutant lines of Lotus japonicus (Regel) Larsen that show defects in nodulation as well as in mycorrhiza formation are valuable resources for studying the events required for the establishment of functional symbioses. In this study, 11 mutant lines derived from a screen for genetic suppressors of har1-1 hypernodulation were assessed quantitatively for their ability to form arbuscular mycorrhizal (AM) symbiosis. The presence of extraradical mycelia, appressoria, intraradical hyphae, arbuscules and vesicles were scored. Roots of the har1-1 parental line were heavily colonised by six weeks after inoculation with the AM fungus Glomus intraradices showing the typical Arum-type colonisation pattern. Five mutants lacked internal root colonisation with blocks either at the surface of epidermal cells or at the outer tangential wall of cortical cells. These AM– lines showed some differences in relation to the amount of extraradical hyphae, the number of appressoria, and the degree of abnormal appressorium morphology. Four mutants had internal root colonisation but at a lower level than the parental line. Two mutants showed no difference from the parental line. Results of this study provide additional genetic resources for studying the mechanism of root colonisation by AM fungi.
Functional genomics of plant transporters in legume nodules
Authors: Benedito Vagner A. , Dai Xinbin , He Ji , Zhao Patrick X. , Udvardi Michael K.
Published: August 2006

Over the past few decades, a combination of physiology, biochemistry, molecular and cell biology, and genetics has given us a basic understanding of some of the key transport processes at work in nitrogen-fixing legume nodules, especially those involved in nutrient exchange between infected plant cells and their endosymbiotic rhizobia. However, our knowledge in this area remains patchy and dispersed over numerous legume species. Recent progress in the areas of genomics and functional genomics of the two model legumes, Medicago truncatula and Lotus japonicus is rapidly filling the gap in knowledge about which plant transporter genes are expressed constitutively in nodules and other organs, and which are induced or expressed specifically in nodules. The latter class in particular is the focus of current efforts to understand specialised, nodule-specific roles of transporters. This article briefly reviews past work on the biochemistry and molecular biology of plant transporters in nodules, before describing recent work in the areas of transcriptomics and bioinformatics. Finally, we consider where functional genomics together with more classical approaches are likely to lead us in this area of research in the future.
An apparent reversal in floral symmetry in the legume
Cadia
is a homeotic transformation
Authors: Citerne Hélène L. , Pennington R. Toby , Cronk Quentin C. B.
Published: August 2006

Within papilionoid legumes, characterized by flowers with strong bilateral symmetry, a derived condition within angiosperms,
Cadia
(
Cadia purpurea
) has reverted to radially symmetrical flowers. Here, we investigate the genetic basis of this morphological reversal. Two orthologues of the floral symmetry gene
CYCLOIDEA
(
CYC
) demarcate the adaxial (dorsal) region of the flower in typical papilionoid legumes. In the model legume
Lotus japonicus
, one of these
LegCYC
genes has been shown, like
CYC
, to be required for the establishment of floral bilateral symmetry. This study shows that these genes are expressed in the adaxial region of the typical papilionoid flower of
Lupinus
, which belongs to the same papilionoid subclade as
Cadia
. In
Cadia
, these genes also are expressed, but the expression pattern of one of these has expanded from the adaxial to the lateral and abaxial regions of the corolla. This result suggests that the radial flowers of
Cadia
are dorsalized and, therefore, are not a true evolutionary reversal but an innovative homeotic transformation, where, in this case, all petals have acquired dorsal identity. This study raises a question over other putative reversals in animals and plants, which also may be cryptic innovations.
Ensemble molecular dynamics yields submillisecond kinetics and intermediates of membrane fusion
Authors: Kasson Peter M. , Kelley Nicholas W. , Singhal Nina , Vrljic Marija , Brunger Axel T. , Pande Vijay S.
Published: August 2006

Lipid membrane fusion is critical to cellular transport and signaling processes such as constitutive secretion, neurotransmitter release, and infection by enveloped viruses. Here, we introduce a powerful computational methodology for simulating membrane fusion from a starting configuration designed to approximate activated prefusion assemblies from neuronal and viral fusion, producing results on a time scale and degree of mechanistic detail not previously possible to our knowledge. We use an approach to the long time scale simulation of fusion by constructing a Markovian state model with large-scale distributed computing, yielding an understanding of fusion mechanisms on time scales previously impossible to simulate to our knowledge. Our simulation data suggest a branched pathway for fusion, in which a common stalk-like intermediate can either rapidly form a fusion pore or remain in a metastable hemifused state that slowly forms fully fused vesicles. This branched reaction pathway provides a mechanistic explanation both for the biphasic fusion kinetics and the stable hemifused intermediates previously observed experimentally. Our distributed computing and Markovian state model approaches provide sufficient sampling to detect rare transitions, a systematic process for analyzing reaction pathways, and the ability to develop quantitative approximations of reaction kinetics for fusion.
Aptamers evolved from live cells as effective molecular probes for cancer study
Authors: Shangguan Dihua , Li Ying , Tang Zhiwen , Cao Zehui Charles , Chen Hui William , Mallikaratchy Prabodhika , Sefah Kwame , Yang Chaoyong James , Tan Weihong
Published: July 2006

Using cell-based aptamer selection, we have developed a strategy to use the differences at the molecular level between any two types of cells for the identification of molecular signatures on the surface of targeted cells. A group of aptamers have been generated for the specific recognition of leukemia cells. The selected aptamers can bind to target cells with an equilibrium dissociation constant (
K
d
) in the nanomolar-to-picomolar range. The cell-based selection process is simple, fast, straightforward, and reproducible, and, most importantly, can be done without prior knowledge of target molecules. The selected aptamers can specifically recognize target leukemia cells mixed with normal human bone marrow aspirates and can also identify cancer cells closely related to the target cell line in real clinical specimens. The cell-based aptamer selection holds a great promise in developing specific molecular probes for cancer diagnosis and cancer biomarker discovery.
Structure of FliM provides insight into assembly of the switch complex in the bacterial flagella motor
Authors: Park Sang-Youn , Lowder Bryan , Bilwes Alexandrine M. , Blair David F. , Crane Brian R.
Published: August 2006

Bacteria switch the direction their flagella rotate to control movement. FliM, along with FliN and FliG, compose a complex in the motor that, upon binding phosphorylated CheY, reverses the sense of flagellar rotation. The 2.0-Å resolution structure of the FliM middle domain (FliM
M
) from
Thermotoga maritima
reveals a pseudo-2-fold symmetric topology similar to the CheY phosphatases CheC and CheX. A variable structural element, which, in CheC, mediates binding to CheD (α2′) and, in CheX, mediates dimerization (β′
x
), has a truncated structure unique to FliM (α2′). An exposed helix of FliM
M
(α1) does not contain the catalytic residues of CheC and CheX but does include positions conserved in FliM sequences. Cross-linking experiments with site-directed cysteine mutants show that FliM self-associates through residues on α1 and α2′. CheY activated by BeF
3
−
binds to FliM with ≈40-fold higher affinity than CheY (
K
d
= 0.04 μM vs. 2 μM). Mapping residue conservation, suppressor mutation sites, binding data, and deletion analysis onto the FliM
M
surface defines regions important for contacts with the stator-interacting protein FliG and for either counterclockwise or clockwise rotation. Association of 33–35 FliM subunits would generate a 44- to 45-nm-diameter disk, consistent with the known dimensions of the C-ring. The localization of counterclockwise- and clockwise-biasing mutations to distinct surfaces suggests that the binding of phosphorylated CheY cooperatively realigns FliM around the ring.
The ATP-sensitive potassium (K
ATP
) channel-encoded
dSUR
gene is required for
Drosophila
heart function and is regulated by
tinman
Authors: Akasaka Takeshi , Klinedinst Susan , Ocorr Karen , Bustamante Erika L. , Kim Seung K. , Bodmer Rolf
Published: August 2006

The homeobox transcription factor Tinman plays an important role in the initiation of heart development. Later functions of Tinman, including the target genes involved in cardiac physiology, are less well studied. We focused on the
dSUR
gene, which encodes an ATP-binding cassette transmembrane protein that is expressed in the heart. Mammalian SUR genes are associated with K
ATP
(ATP-sensitive potassium) channels, which are involved in metabolic homeostasis. We provide experimental evidence that Tinman directly regulates
dSUR
expression in the developing heart. We identified a
cis
-regulatory element in the first intron of
dSUR
, which contains Tinman consensus binding sites and is sufficient for faithful
dSUR
expression in the fly’s myocardium. Site-directed mutagenesis of this element shows that these Tinman sites are critical to
dSUR
expression, and further genetic manipulations suggest that the GATA transcription factor Pannier is synergistically involved in cardiac-restricted
dSUR
expression
in vivo
. Physiological analysis of
dSUR
knock-down flies supports the idea that dSUR plays a protective role against hypoxic stress and pacing-induced heart failure. Because
dSUR
expression dramatically decreases with age, it is likely to be a factor involved in the cardiac aging phenotype of
Drosophila
.
dSUR
provides a model for addressing how embryonic regulators of myocardial cell commitment can contribute to the establishment and maintenance of cardiac performance.
Age-dependent accumulation of recombinant cells in the mouse pancreas revealed byin situfluorescence imaging
Authors: Wiktor-Brown Dominika M. , Hendricks Carrie A. , Olipitz Werner , Engelward Bevin P.
Published: August 2006

Mitotic homologous recombination (HR) is critical for the repair of double-strand breaks, and conditions that stimulate HR are associated with an increased risk of deleterious sequence rearrangements that can promote cancer. Because of the difficulty of assessing HR in mammals, little is known about HR activity in mammalian tissues or about the effects of cancer risk factors on HRin vivo. To study HRin vivo, we have used fluorescent yellow direct repeat mice, in which an HR event at a transgene yields a fluorescent phenotype. Results show that HR is an active pathway in the pancreas throughout life, that HR is inducedin vivoby exposure to a cancer chemotherapeutic agent, and that recombinant cells accumulate with age in pancreatic tissue. Furthermore, we developed anin situimaging approach that reveals an increase in both the frequency and the sizes of isolated recombinant cell clusters with age, indicating that bothde novorecombination events and clonal expansion contribute to the accumulation of recombinant cells with age. This work demonstrates that aging and exposure to a cancer chemotherapeutic agent increase the frequency of recombinant cells in the pancreas, and it also provides a rapid method for revealing additional factors that modulate HR and clonal expansionin vivo.
Beyond the metal-insulator transition in polymer electrolyte gated polymer field-effect transistors
Authors: Dhoot Anoop S. , Yuen Jonathan D. , Heeney Martin , McCulloch Iain , Moses Daniel , Heeger Alan J.
Published: July 2006

We have studied the carrier transport in poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-
b
]thiophene) field-effect transistors (FETs) at very high field-induced carrier densities (10
15
cm
−2
) using a polymer electrolyte as gate and gate dielectric. At room temperature, we find high current densities, 2 × 10
6
A/cm
2
, and high metallic conductivities, 10
4
S/cm, in the FET channel; at 4.2 K, the current density is sustained at 10
7
A/cm
2
. Thus, metallic conductivity persists to low temperatures. The carrier mobility in these devices is ≈3.5 cm
2
·V
−1
·s
−1
at 297 K, comparable with that found in fully crystalline organic devices.
Dendrites of rod bipolar cells sprout in normal aging retina
Authors: Liets Lauren C. , Eliasieh Kasra , van der List Deborah A. , Chalupa Leo M.
Published: August 2006

The aging nervous system is known to manifest a variety of degenerative and regressive events. Here we report the unexpected growth of dendrites in the retinas of normal old mice. The dendrites of many rod bipolar cells in aging mice were observed to extend well beyond their normal strata within the outer plexiform layer to innervate the outer nuclear layer where they appeared to form contacts with the spherules of rod photoreceptors. Such dendritic sprouting increased with age and was evident at all retinal eccentricities. These results provide evidence of retinal plasticity associated with normal aging.
Psychiatric and psychosomatic symptoms are increasing problems among Swedish schoolchildren
Authors: Cederquist Åse Victorin
Published: August 2006

Paediatricians and other professionals in Sweden note that the amount of children with psychiatric and psychosomatic symptoms is growing in number. Suicide attempts among the young (15–24 y) increased by more than 30% from 1998–2003. The Swedish National Board for Health and Welfare's 2004 guidelines for school healthcare shed light on this increasing problem among schoolchildren. An article in this issue of Acta Paediatrica, “Living conditions and psychosomatic complaints in Swedish schoolchildren”, analyses economic stress as a causative factor leading to psychosomatic symptoms such as headache, abdominal pain and difficulty in falling asleep. Living conditions, however, most likely include other factors related to our modern and ever‐changing society that also have an impact on the growing child.

Conclusion: Psychiatric health is changing for the worse among Swedish schoolchildren. The cause is multifactorial. Economic stress is one factor, but there are also other possible causes related to modern society that correlate to the increase of psychosomatic problems among schoolchildren. Three major problems are among those suspected: impaired education and deficient working environment in Swedish schools, a general lack of adult contact and guidance, and excessive computer and TV use.
Activated Osteoclasts with CD51/61 Expression in Otosclerosis
Authors: Karosi Tamás , Jókay István , Kónya József , Petkó Mihály , Szabó László Z. , Pytel József , Jóri József , Sziklai István
Published: August 2006

Hypothesis: Stapes ankylosis is supposed to be a disease with variable histopathology caused by otosclerosis or pseudo‐otosclerosis. Persistent measles virus infection of the otic capsule could induce reactivation of quiescent embryonic osteoclasts in otosclerosis.

Background: Presence of measles virus RNA was demonstrated in the footplates of otosclerotic patients by reverse‐transcription polymerase chain reaction (RT‐PCR). Histology of active otosclerosis is featured by the presence of numerous osteoclasts with unknown phenotype.

Methods: Nucleic acid was extracted from stapes footplates of clinically otosclerotic patients (n = 261). Genomic RNA of measles virus was amplified by RT‐PCR. Amplification results were correlated to postoperative histologic and CD51/61 specific immunohistologic findings. A parallel alcalic phosphatase activity assessment was performed to evaluate the metabolic activity of osteoclasts in each section.

Results: Among 261 stapes fixation cases, 175 otosclerotic stapes contained measles virus RNA. Histology for virus negative stapes (n = 86) represented nonotosclerotic, degenerative disorders. Histologically confirmed otosclerosis was featured by the presence of osteoclasts with renewed, embryonic phenotype. In otosclerosis, alcalic phosphatase activity was significantly higher compared with nonotosclerotic stapes ankylosis (P < .001).

Conclusion: The presence of CD51/61 positive osteoclasts in otosclerotic bone containing viral sequences provides the basis for an inflammatory bone remodeling disorder. Otosclerosis is a disease caused by persistent measles virus infection and reactivation of resting embryonic osteoclasts in the otic capsule.
Divergence of Fine and Gross Motor Skills in Prelingually Deaf Children: Implications for Cochlear Implantation
Authors: Horn David L. , Pisoni David B. , Miyamoto Richard T.
Published: August 2006

Objective: The objective of this study was to assess relations between fine and gross motor development and spoken language processing skills in pediatric cochlear implant users.

Study Design: The authors conducted a retrospective analysis of longitudinal data.

Methods: Prelingually deaf children who received a cochlear implant before age 5 and had no known developmental delay or cognitive impairment were included in the study. Fine and gross motor development were assessed before implantation using the Vineland Adaptive Behavioral Scales, a standardized parental report of adaptive behavior. Fine and gross motor scores reflected a given child's motor functioning with respect to a normative sample of typically developing, normal‐hearing children. Relations between these preimplant scores and postimplant spoken language outcomes were assessed.

Results: In general, gross motor scores were found to be positively related to chronologic age, whereas the opposite trend was observed for fine motor scores. Fine motor scores were more strongly correlated with postimplant expressive and receptive language scores than gross motor scores.

Conclusions: Our findings suggest a disassociation between fine and gross motor development in prelingually deaf children: fine motor skills, in contrast to gross motor skills, tend to be delayed as the prelingually deaf children get older. These findings provide new knowledge about the links between motor and spoken language development and suggest that auditory deprivation may lead to atypical development of certain motor and language skills that share common cortical processing resources.
Dramatic Changes in Home‐based Enteral Nutrition Practices in Children During an 11‐year Period
Authors: Daveluy Walter , Guimber Dominique , Uhlen Stéphanie , Lescut Dominique , Michaud Laurent , Turck Dominique , Gottrand Frédéric
Published: July 2006

Objectives:

Experience with pediatric home‐based enteral nutrition (HEN), in particular series including children only, has been reported only rarely. We investigated the evolution of pediatric HEN activity during an 11‐year period.

Methods:

All patients aged 17 years or younger who started HEN between January 1990 and December 2000 were included in this retrospective study.

Results:

The annual number of patients treated with HEN increased dramatically from 16 in 1990 to 200 in 2000, with more than 65 new patients every year since 1999 (P < 0.0001). The mean age at the commencement of HEN decreased from 6.2 ± 1.4 (SEM) to 4.8 ± 0.7 years (P = 0.006). The use of nasogastric tubes decreased from 63% in 1990 to 35% in 1998 (P = 0.009), and the use of gastrostomy increased from 50% to 60% from 1994 onward. The proportion of patients with digestive diseases commencing HEN in each year decreased from more than 40% before 1996 to less than 32% in 2000 (P = 0.009). Commercially manufactured pediatric diets were used increasingly (P = 0.0006).

Conclusions:

The evolution of HEN was marked by changes in the population treated and the modes of treatment after the emergence of gastrostomy and commercial diets. This justified the creation of a multidisciplinary, pediatric artificial nutrition unit.
Probiotic Intervention in the First Months of Life
Authors: Rinne Minna , Kalliomäki Marko , Salminen Seppo , Isolauri Erika
Published: July 2006

Objectives:

To determine whether probiotics administered for 6 months postnatally affect gastrointestinal symptoms, crying and the compositional development of the gut microbiota through infancy.

Methods:

The study comprised of 132 newborns whose mothers were randomized to receive placebo or Lactobacillus rhamnosus GG (ATCC 53103) before delivery. The treatments of mothers/infants continued for 6 months postnatally. A specific symptom chart was used to monitor gastrointestinal symptoms and infant's crying during the 7th and the 12th weeks of life. Fluorescent in situ hybridization was used to establish the Bifidobacterium, Lactobacillus/Enterococcus, Bacteroides and Clostridium counts in fecal samples at 6, 12, 18 and 24 months of age.

Results:

Numbers of different types of stools, vomits and crying time were comparable between the groups during the 7th and the 12th weeks of life. Dominant microbiota consisted of bifidobacteria throughout the study. At 6 months, there were less clostridia in faeces in the placebo compared with the probiotic group (P = 0.026), whereas after long‐term follow‐up at 2 years, there were less lactobacilli/enterococci and clostridia in faeces in the probiotic group than in the placebo group (P = 0.011 and P = 0.032, respectively), reflecting the impact of clostridia as a marker of microbiota succession in healthy infants.

Conclusions:

Probiotic administration in the first months of life was well tolerated and did not significantly interfere with long‐term composition or quantity of gut microbiota.
What Is the Evidence on the Practice of Mucous Fistula Refeeding in Neonates With Short Bowel Syndrome?
Authors: Richardson Lydia , Banerjee Sujoy , Rabe Heike
Published: July 2006

A systematic review of literature was performed on the practice of mucous fistula refeeding in neonates with short bowel syndrome. No randomised controlled studies were identified. Case series reports of 30 infants showed improved weight gain (from −2.36 ± 1.24 to 21.06 ± 3.02 g/d) and reduced need for total parenteral nutrition. Randomised controlled trials are required to establish the benefits of mucous fistula refeeding in this condition.
Gene Transfer to the Gastrointestinal Tract After Peroral Administration of Recombinant Adeno‐associated Virus Type 2 Vectors
Authors: Shao Guohong , Greathouse Kristin , Huang Qin , Wang Chiou‐Miin , Sferra Thomas J.
Published: July 2006

Objectives:

The transfer of exogenous genetic material to cells within the gastrointestinal (GI) tract has many potential therapeutic applications. An attractive feature of the GI tract for gene transfer is its accessibility through the orogastric route. In this study, we evaluated the stability of recombinant adeno‐associated virus type 2 (rAAV2) vectors within the GI tract and whether rAAV2‐mediated gene transfer could be increased through manipulation of the intraluminal environment.

Methods:

The stability of rAAV2 vectors carrying β‐galactosidase and enhanced green fluorescence protein transgenes was determined in the presence of hydrochloric acid, pepsin, trypsin, chymotrypsin gastric fluid and intestinal fluid and after in vivo administration. For in vivo experiments, the rAAV2 vector carrying the β‐galactosidase transgene was administered perorally to FVB/NJ mice. Groups of mice received the vector alone or in combination with sodium bicarbonate and aprotinin. Gene transfer to the stomach and small intestine was evaluated by polymerase chain reaction and histochemical assays.

Results:

The stability of rAAV2 was reduced by hydrochloric acid, trypsin, chymotrypsin, gastric fluid and intestinal fluid. The vector was not stable within the lumen of the GI tract. Gastric acid neutralization with sodium bicarbonate and protease inhibition with aprotinin increased the in vivo stability of the vector and the level of gene transfer to the stomach and all regions of the small bowel. In both groups of mice (vector alone and vector plus sodium bicarbonate and aprotinin), transgene‐derived protein expression (β‐galactosidase) was below the level of detection of the histochemical assay.

Conclusions:

Recombinant AAV2 are adversely affected by physiological conditions within the proximal GI tract. Gastric acid neutralization and inhibition of intestinal protease activity improved rAAV2 stability and increased the level of gene transfer within the GI tract. Despite these changes, transduction of the GI tract after peroral rAAV2 administration remained low.
Glucagon‐like Peptide 2 Stimulates Intestinal Nutrient Absorption in Parenterally Fed Newborn Pigs
Authors: Sangild P.T. , Tappenden K.A. , Malo C. , Petersen Y.M. , Elnif J. , Bartholome A.L. , Buddington R.K.
Published: July 2006

Objectives:

Parenteral nutrition is a critically important intervention for children with intestinal dysfunctions. However, total parenteral nutrition (TPN) with no enteral feeding is associated with small intestine atrophy and malabsorption, which complicate the transition to enteral nutrition. The objective of the present study was to evaluate the therapeutic potential of the intestinotrophic peptide glucagon‐like peptide 2 (GLP‐2), which reduces TPN‐associated atrophy and maintains nutrient absorption in adult rats, for preventing nutrient malabsorption in neonates receiving TPN.

Methods:

Term pigs obtained by cesarean delivery received from birth TPN alone (TPN; n = 7) or TPN with GLP‐2 (25 nmol · kg−1 · d−1; GLP‐2; n = 8) or were fed sow milk enterally (n = 7). The small intestine was removed on postnatal day 6 to measure morphological responses and absorption of glucose, leucine, lysine and proline by intact tissues and brush border membrane vesicles and to quantify the abundances of mRNA and protein for enterocyte glucose transporters (SGLT‐1 and GLUT2).

Results:

Relative to TPN alone, administration of GLP‐2 resulted in small intestines that were larger (P < 0.01), had greater abundances of mRNA and protein for SGLT‐1, but not for GLUT2, and had higher capacities to absorb nutrients (P < 0.01). Moreover, the intestines of GLP‐2 pigs were comparable in size and absorptive capacities with those of pigs fed sow milk enterally.

Conclusions:

Providing GLP‐2 to neonates receiving TPN prevents small intestine atrophy, results in small intestine absorptive capacities that are comparable to when nutrients are provided enterally and may accelerate the transition from TPN to enteral nutrition.