bluuebunny/crossref_metadata_2025 huggingface dataset:
A design approach for systems based on magnetic pulse compression
Authors: Praveen Kumar D. Durga , Mitra S. , Senthil K. , Sharma D. K. , Rajan Rehim N. , Sharma Archana , Nagesh K. V. , Chakravarthy D. P.
Published: April 2008

A design approach giving the optimum number of stages in a magnetic pulse compression circuit and gain per stage is given. The limitation on the maximum gain per stage is discussed. The total system volume minimization is done by considering the energy storage capacitor volume and magnetic core volume at each stage. At the end of this paper, the design of a magnetic pulse compression based linear induction accelerator of 200kV, 5kA, and 100ns with a repetition rate of 100Hz is discussed with its experimental results.
Size-dependent structure transformation from amorphous phase to crystal
Authors: Fang Jixiang , You Hongjun , Kong Peng , Ding Bingjun , Song Xiaoping
Published: April 2008

A size-dependent crystal growth mechanism is studied by molecular dynamics simulations. The amorphous silver firstly deposits under the coordinated actions between the lattice mismatch and interactions between silver atoms and the surrounding water. Then, silver nuclei spontaneously form once the amorphous layer exceeds a critical thickness. Water molecule absorption on the outmost surface of silver clusters contributes to the continuous deposition of silver amorphous phase.
Evaluation of carrier velocity using time-resolved optical second harmonic generation measurement
Authors: Manaka Takaaki , Nakao Motoharu , Lim Eunju , Iwamoto Mitsumasa
Published: April 2008

The velocity of carrier motion in pentacene field effect transistor (FET) was evaluated by the time-resolved microscopic second harmonic generation (SHG) measurement. Under the pulse operation of organic FET (OFET), time evolution of the electric field distribution along the channel is observed by changing the delay time between laser pulses and voltage pulses that drive OFET. The peak position of SHG profile moves along OFET channel from source to drain electrode with increase in delay time reflecting carrier motion. The time-resolved SHG technique enables us to evaluate carrier velocity by tracing motion of the SHG peak.
Wide wavelength tuning of GaAs∕AlxGa1−xAs bound-to-continuum quantum cascade lasers by aluminum content control
Authors: Heinrich J. , Langhans R. , Vitiello M. S. , Scamarcio G. , Indjin D. , Evans C. A. , Ikonić Z. , Harrison P. , Höfling S. , Forchel A.
Published: April 2008

Tuning of the emission wavelength in GaAs∕AlxGa1−xAs bound-to-continuum quantum cascade lasers with different Al mole fractions (x) is reported. By varying x in the range of 0.37–0.52, a shift of the emission wavelengths of over 4μm has been observed. Using this method, laser action in the range of 11.2–15.3μm at temperatures T⩾260K has been demonstrated with a record value of ∼340K for GaAs based QCLs operating at 13.5μm.
Highly efficient surface enhanced Raman scattering using microstructured optical fibers with enhanced plasmonic interactions
Authors: Peacock Anna C. , Amezcua-Correa Adrian , Yang Jixin , Sazio Pier J. A. , Howdle Steven M.
Published: April 2008

Microstructured optical fibers (MOFs) represent a promising platform technology for fully integrated photonic-plasmonic devices. In this paper, we experimentally investigate the properties of two MOF templates impregnated with silver nanoparticles via a high pressure chemical deposition technique. By comparing fiber templates with different air filling fractions, we have quantified the importance of an increased field-particle overlap for improved surface enhanced Raman scattering sensitivity for the next generation of optical fiber sensors.
Polarized photoluminescence and time-resolved photoluminescence from single CdS nanosheets
Authors: Hoang T. B. , Titova L. V. , Mishra A. , Smith L. M. , Jackson H. E. , Lee K.-Y. , Rho H. , Yarrison-Rice J. M. , Choi Y.-J. , Choi K. J. , Park J.-G.
Published: April 2008

We have utilized polarized low temperature photoluminescence (PL) to probe the electronic states and structural symmetries of individual CdS nanosheets. High resolution transmission electron microscopy measurements indicate highly crystalline material with different nanosheets exhibiting significant variations of the direction of the c axis, which are consistent with polarization measurements of PL from single CdS nanosheets. The quality of the nanosheets is reflected in measurements of exciton lifetimes of ∼200ps, a value significantly longer than observed for CdS nanowires whose diameter is the same as the thickness of these nanosheets, but shorter than that observed in bulk crystals.
Electric field assisted annealing and formation of prominent deep-level defect in ion-implanted n-type 4H-SiC
Authors: Wong-Leung J. , Svensson B. G.
Published: April 2008

High-purity and low-doped n-type epitaxial layers of 4H-SiC have been implanted with N and C ions by using energies in the MeV range and doses from 2×108to1×109cm−2. Postimplant annealing was performed at 1100°C prior to sample analysis by deep-level transient spectroscopy (DLTS). A drastic and irreversible instability of the prominent EH7 deep-level defect occurs during the first DLTS temperature scan because of the electric field applied during the measurements. Depending on the implanted species, EH7 can decrease (N implants) as well as increase (C implants) in strength and the effect is attributed to charge-state controlled annealing and formation processes of EH7. The origin of EH7 is discussed and the experimental data support a model invoking interstitial C atoms.
Complete sets of elastic, dielectric, and piezoelectric properties of flux-grown [011]-poled Pb(Mg1∕3Nb2∕3)O3-(28–32)% PbTiO3 single crystals
Authors: Shanthi M. , Lim L. C. , Rajan K. K. , Jin J.
Published: April 2008

Complete sets of elastic, dielectric, and piezoelectric properties of flux-grown rhombohedral PMN-(28–30)%PT and orthorhombic PMN-32%PT single crystals, poled along the [011]-thickness direction, have been determined. This crystal cut exhibits very high longitudinal-extension, transverse, and shear piezoelectric properties when existing in the rhombohedral state (for PMN-28%PT and PMN-30%PT) but much inferior properties when existing in the ovepoled orthorhombic state (notably for PMN-32%PT). Careful control of crystal composition and poling conditions is thus important when using PMN-PT single crystals in piezoelectric devices.
Innovative surface acoustic wave sensor for accurate measurement of subatmospheric pressure
Authors: Nicolay P. , Elmazria O. , Sarry F. , Bouvot L. , Marche N. , Kambara H.
Published: April 2008

An original application for surface acoustic wave (SAW) subatmospheric pressure sensor was developed to measure pressure below 100mTorr with very high precision. The basic operating principles and the most significant experimental results of the sensor are presented here. A simple theoretical model is proposed. This sensor provides an efficient measuring solution in a wide range of subatmospheric pressure, which has been inaccessible in past by conventional diaphragm-based SAW sensors.
Transition from anomalous kinetics toward Fickian diffusion for Si dissolution into amorphous Ge
Authors: Balogh Zoltán , Erdélyi Zoltán , Beke Dezső L. , Langer Gábor A. , Csik Attila , Boyen Hans-Gerd , Wiedwald Ulf , Ziemann Paul , Portavoce Alain , Girardeaux Christophe
Published: April 2008

Over the last years, several experimental and theoretical studies of diffusion kinetics on the nanoscale have shown that the time evolution (x∝tkc) differs from the classical Fickian law (kc=0.5). However, all work was based on crystalline samples or models, so far. In this letter, we report on the diffusion kinetics of a thin amorphous Si layer into amorphous Ge to account for the rising importance of amorphous materials in nanodevices. Employing surface sensitive techniques, the initial kc was found at 0.7±0.1. Moreover, after some monolayers of Si dissolved into the Ge, kc changes to the generally expected classical Fickian law with kc=0.5.
Bioinspired broadband antireflection coatings on GaSb
Authors: Min Wei-Lun , Betancourt Amaury P. , Jiang Peng , Jiang Bin
Published: April 2008

We report an inexpensive yet scalable templating technique for fabricating moth-eye antireflection gratings on gallium antimonide substrates. Non-close-packed colloidal monolayers are utilized as etching masks to pattern subwavelength-structured nipple arrays on GaSb. The resulting gratings exhibit superior broadband antireflection properties and thermal stability than conventional multilayer dielectric coatings. The specular reflection of the templated nipple arrays match with the theoretical predictions using a rigorous coupled-wave analysis model. The effect of the nipple shape and size on the antireflection properties has also been investigated by the same model. These biomimetic coatings are of great technological importance in developing efficient thermophotovoltaic cells.
Polarization resolved luminescence in asymmetric n-type GaAs∕AlGaAs resonant tunneling diodes
Authors: dos Santos L. F. , Galvão Gobato Y. , Lopez-Richard V. , Marques G. E. , Brasil M. J. S. P. , Henini M. , Airey R. J.
Published: April 2008

We have investigated the polarized emission from a n-type GaAs∕AlGaAs resonant tunneling diode under magnetic field. The GaAs contact layer emission shows a large constant negative circular polarization. A similar result is observed for the quantum well, but only when electrons are injected from the substrate, while for inverted biases, the polarization tends to become positive for small voltages and large laser excitation intensities. We believe that the quantum well polarization may be associated to the partial thermalization of minority carriers on the well subbands and is thus critically dependent on the bias-controlled density of carriers accumulated in the well.
Terahertz emission by quantum beating in a modulation doped parabolic quantum well
Authors: Bell L. , Rogers J. , Heyman J. N. , Zimmerman J. D. , Gossard A. C.
Published: April 2008

We use ultrafast terahertz spectroscopy to observe terahertz-frequency electron oscillations in a modulation-doped InGaAs∕AlGaAs parabolic quantum well with subband spacing 0.01eV. Our study examined how the extrinsic electron density in the well influences terahertz emission efficiency and we found no strong dependence. This indicates that terahertz emission in this structure arises from quantum beating of the photogenerated electrons. Terahertz emission from the cold extrinsic electrons due to ultrafast field screening plays at most a secondary role.
Leptin inhibits basal but not gonadotrophin-stimulated testosterone production in the immature mouse and sheep testis
Authors: Herrid Muren , Xia Yin , O'Shea Tim , McFarlane James R.
Published: April 2008

The mechanisms whereby leptin regulates testosterone secretion are complex and are likely to involve actions at different levels of the hypothalamus–pituitary–gonadal axis. In the present study, the effect of leptin on testicular steroidogenesis at different developmental stages in mice and sheep was investigated. Testosterone data from testicular slice and Leydig cells of immature and adult mice testes demonstrated that the action of leptin in the regulation of steroidogenesis appears to be dependent on the developmental stage of the testis. Leptin biphasically modulates basal testosterone production in immature testicular slice cultures: at relatively low concentrations (6.25–12.5 ng mL–1) leptin exerts a significant inhibitory effect, but has less of an effect at very low (1.25 ng mL–1) or high concentrations (25 ng mL–1). However, leptin failed to modulate basal testosterone levels in Leydig cell preparations. In contrast with immature testes, leptin was unable to regulate either basal or human chorionic gonadotrophin (10 IU mL–1)-stimulated testosterone production in adult testicular slices or Leydig cell cultures. The age- and concentration-dependent regulation pattern was confirmed using sheep testicular slice culture. Leptin (1.56–25 ng mL–1) significantly inhibited basal testosterone production in the testis from birth to Day 21, but had no effect on Day 27 or older testes. However, the plasma and testicular concentrations of leptin and testosterone data in the ram indicate that such a regulatory effect of leptin on testis steroidogenesis in vitro is unable to efficiently influence testosterone concentrations in vivo. This does not exclude the possibility of a non-competitive mechanism of interaction between leptin and luteinising hormone to regulate testosterone production. Thus, we hypothesise that leptin is not an important independent regulator of testosterone concentration in the normal physiological state. The physiological significance and mechanism of leptin regulation of basal testosterone production are not known; further studies are required to elucidate these important issues.
Effect of type of cryoprotectant on morphology and developmental competence of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow freezing or vitrification
Authors: Gautam S. K. , Verma V. , Palta P. , Chauhan M. S. , Manik R. S.
Published: April 2008

The present study examined the effects of different cryoprotectants on morphology and developmental competence of in vitro-matured buffalo oocytes after slow freezing or vitrification. After slow freezing in dimethyl sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or 1.5 m each, the proportion of morphologically normal oocytes recovered was significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the percentage of morphologically normal oocytes recovered was lower (P < 0.01) for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The most common damage, irrespective of the cryopreservation method, was loss of cumulus mass. The cleavage rate and the proportion of vitrified–warmed oocytes that developed to morulae/blastocysts were significantly higher (P < 0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v. 0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in 1.5 m DMSO. In conclusion, vitrification was more effective than slow freezing for the cryopreservation of in vitro-matured buffalo oocytes.
Transition from quasiperiodicity to chaos just before sawtooth crash in the ASDEX Upgrade tokamak
Authors: Igochine V. , Dumbrajs O. , Zohm H.
Published: April 2008

In this paper we investigate the sawtooth crash in the ASDEX Upgrade tokamak and present evidence supporting the hypothesis of stochastization of magnetic field lines during the crash. We demonstrate on the basis of soft x-ray and electron cyclotron emission measurements that during the pre-crash phase the quasiperiodic transition to chaos occurs. Magnetohydrodynamic oscillations with two frequencies develop before the crash. Consistent with the most energetically favourable transition from quasiperiodicity to chaos, their frequency ratio is close to the conjugate golden ratio. We think that the sawtooth crash has a universal stochastic character and it would be worthwhile to search for these transition signatures in other tokamaks.
TAE internal structure through high-resolution soft x-ray measurements in ASDEX-Upgrade
Authors: Piovesan P. , Igochine V. , Lauber P. , Sassenberg K. , Flaws A. , García-Muñoz M. , Günter S. , Maraschek M. , Marrelli L. , Martin P. , Mc Carthy P.J.
Published: April 2008

The internal structure of toroidal Alfvén eigenmodes (TAEs) excited in ASDEX-Upgrade plasmas with ion cyclotron resonance heating (ICRH) has been measured through a high-resolution multichord soft x-ray diagnostic. The radial profiles of multiple TAEs are compared with predictions of the linear resistive magnetohydrodynamic code CASTOR and the nonperturbative gyrokinetic code LIGKA and reasonably good agreement is found. The evolution of the TAE radial profiles could be followed in time, both across sawteeth in pure ICRH discharges and in discharges with different types of transitions from L-mode to H-mode obtained with a combination of ICRH and neutral beam injection.
Plasma inductance and stability metrics on Alcator C-Mod
Authors: Ferrara M. , Hutchinson I.H. , Wolfe S.M.
Published: April 2008

The growth rate of the vertical instability of elongated plasmas increases with the internal inductance. An upper limit to the value of the internal inductance is found, based on analytic approximations, and validated through the analysis of a large database of Alcator C-Mod plasmas. The extrapolation to ITER suggests that low-current high-q95plasmas could exceed the original design value ofliand thus be more difficult to stabilize. Metrics to characterize the vertical stability of tokamak plasmas are discussed and calculated for typical and ITER-like C-Mod plasmas. These figures contribute to the assessment of the ITER vertical stabilization loop and the establishment of what performance margin is required.
ERdj4 and ERdj5 Are Required for Endoplasmic Reticulum-associated Protein Degradation of Misfolded Surfactant Protein C
Authors: Dong Mei , Bridges James P. , Apsley Karen , Xu Yan , Weaver Timothy E.
Published: April 2008

Mutations in the SFTPC gene associated with interstitial lung disease in human patients result in misfolding, endoplasmic reticulum (ER) retention, and degradation of the encoded surfactant protein C (SP-C) proprotein. In this study, genes specifically induced in response to transient expression of two disease-associated mutations were identified by microarray analyses. Immunoglobulin heavy chain binding protein (BiP) and two heat shock protein 40 family members, endoplasmic reticulum-localized DnaJ homologues ERdj4 and ERdj5, were significantly elevated and exhibited prolonged and specific association with the misfolded proprotein; in contrast, ERdj3 interacted with BiP, but it did not associate with either wild-type or mutant SP-C. Misfolded SP-C, ERdj4, and ERdj5 coprecipitated with p97/VCP indicating that the cochaperones remain associated with the misfolded proprotein until it is dislocated to the cytosol. Knockdown of ERdj4 and ERdj5 expression increased ER retention and inhibited degradation of misfolded SP-C, but it had little effect on the wild-type protein. Transient expression of ERdj4 and ERdj5 in X-box binding protein 1−/− mouse embryonic fibroblasts substantially restored rapid degradation of mutant SP-C proprotein, whereas transfection of HPD mutants failed to rescue SP-C endoplasmic reticulum-associated protein degradation. ERdj4 and ERdj5 promote turnover of misfolded SP-C and this activity is dependent on their ability to stimulate BiP ATPase activity.
A system for generating transcription regulatory networks with combinatorial control of transcription
Authors: Roy Sushmita , Werner-Washburne Margaret , Lane Terran
Published: April 2008

Summary: We have developed a new software system, REgulatory Network generator with COmbinatorial control (RENCO), for automatic generation of differential equations describing pre-transcriptional combinatorics in artificial regulatory networks. RENCO has the following benefits: (a) it explicitly models protein–protein interactions among transcription factors, (b) it captures combinatorial control of transcription factors on target genes and (c) it produces output in Systems Biology Markup Language (SBML) format, which allows these equations to be directly imported into existing simulators. Explicit modeling of the protein interactions allows RENCO to incorporate greater mechanistic detail of the transcription machinery compared to existing models and can provide a better assessment of algorithms for regulatory network inference.

Availability: RENCO is a C++ command line program, available at http://sourceforge.net/projects/renco/

Contact:  terran@cs.unm.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Differential Regulation of the Expression of Two High-Affinity Sulfate Transporters, SULTR1.1 and SULTR1.2, in Arabidopsis
Authors: Rouached Hatem , Wirtz Markus , Alary Remi , Hell Rüdiger , Arpat A. Bulak , Davidian Jean-Claude , Fourcroy Pierre , Berthomieu Pierre
Published: April 2008

The molecular mechanisms regulating the initial uptake of inorganic sulfate in plants are still largely unknown. The current model for the regulation of sulfate uptake and assimilation attributes positive and negative regulatory roles to O-acetyl-serine (O-acetyl-Ser) and glutathione, respectively. This model seems to suffer from exceptions and it has not yet been clearly validated whether intracellular O-acetyl-Ser and glutathione levels have impacts on regulation. The transcript level of the two high-affinity sulfate transporters SULTR1.1 and SULTR1.2 responsible for sulfate uptake from the soil solution was compared to the intracellular contents of O-acetyl-Ser, glutathione, and sulfate in roots of plants submitted to a wide diversity of experimental conditions. SULTR1.1 and SULTR1.2 were differentially expressed and neither of the genes was regulated in accordance with the current model. The SULTR1.1 transcript level was mainly altered in response to the sulfur-related treatments. Split-root experiments show that the expression of SULTR1.1 is locally regulated in response to sulfate starvation. In contrast, accumulation of SULTR1.2 transcripts appeared to be mainly related to metabolic demand and is controlled by photoperiod. On the basis of the new molecular insights provided in this study, we suggest that the expression of the two transporters depends on different regulatory networks. We hypothesize that interplay between SULTR1.1 and SULTR1.2 transporters could be an important mechanism to regulate sulfate content in the roots.
Phyllotaxis of vegetative shoots, lamina rotation and their systematic implication in Magnoliaceae
Authors: Liao W. F. , Xia N. H.
Published: April 2008

Phyllotaxis in vegetative shoots and lamina rotation of Magnoliaceae are described. Most genera in Magnoliaceae investigated (except Parakmeria, Manglietiastrum and Pachylarnax) show lamina rotation. Paraphoric, a new type of lamina rotation differing from four other types depicted by Charlton is clarified. Manglietia, Parakmeria, Manglietiastrum, Talauma, section Gwillimia and Rytidospermum in subgenus Magnolia, shoots of Woonyoungia, section Theorhodon and Liriodendron have spiral phyllotaxis, however Magnolia section Oyama and Maingola, Alcimandra, Michelia, Paramichelia, Tsoogiodendron, buds of Woonyoungia, section Theorhodon and Liriodendron have distichous phyllotaxis. The systematic implication of vegetative shoot phyllotaxis and lamina rotation in Magnoliaceae is discussed in this paper.
A reinvestigation into the taxonomic status of Riccia himalayensis and Riccia discolor based on scanning electron microscopic and chemotaxonomical studies
Authors: Mondal Amal Kumar
Published: April 2008

Riccia himalayensis St. (Ms.) Kashyap is a common species found in the Himalayas from the foot of the mountains to an altitude of 2743 m. Ricciadiscolor Lehm. et Lindb. on the other hand, is the common and most widely distributed monsoon species, that has been reported from both the western and eastern Himalayas, as well as from the plains of Assam, west Bengal, Madhya Pradesh, south India, etc. Dispute still exists regarding the taxonomic status of R. himalayensis, which is considered a synonym of R. discolor by some taxonomists, according to whom R. himalayensis has no specific status. This has led to a lot of errors in interpreting R. discolor. On the other hand many authors have considered R. himalayensis to be a composite species of R. discolor, R. billardieri and R. gangetica.

The present investigation was aimed to reinvestigate the taxonomic status of R. himalayensis and R. discolor based on morphological analysis of thallus and spore surface by light microscope and scanning electron microscopy (SEM) studies and biochemical analyses of the protein profile by SDS‐PAGE. Results reveal that although the two species share certain common morphological features, they are two distinct species chemotaxonomically.
Ecological and genetic notes on Lindsaea digitata (Lindsaeaceae), a new fern species from western Amazonia
Authors: Lehtonen Samuli , Tuomisto Hanna
Published: April 2008

Morphological, ecological and genetic evidence have revealed the existence of two sympatric species in what has previously been recognised as Lindsaea divaricata Klotzsch. The new species, Lindsaea digitata Lehtonen & Tuomisto, is described here, and its ecological and genetic differences from the apparently closely related L. divaricata are documented.
On Hieracium incurrens (Asteraceae) and similar species in central Sweden
Authors: Tyler Torbjörn
Published: April 2008

Hieracium incurrens Saelan ex Norrl., originally described from Finland, has been reported from Sweden several times and independently by different authors. Still, however, its presence in Sweden has remained dubious and it has become obvious that the different reports are referable to different taxa and the name has thus been, at least partially, misapplied. In the present study, all Swedish material and putative taxa that have been suggested to belong to H. incurrens, as well as some additional closely similar taxa, is critically compared with authentic material of the latter from Finland. It is concluded that H. incurrens do indeed occur in central Sweden, namely in the eastern coastal provinces closest to Finland. However, the relevant material has mostly been referred to H. longilingua Johanss., which is here considered to be a later synonym of H. incurrens. Material previously referred to H. incurrens from other parts of Sweden does, however, represent other taxa. Five accepted species of this affinity are described and discussed in some detail and one species, viz. H. oestmanii T. Tyler is described anew. In addition, the unrelated species H. arnoldii T. Tyler is described anew based on material from the provinces of Hälsingland and Medelpad.
Composition, geographical affinities and endemism of the Iberian Peninsula orchid flora
Authors: Bernardos Sonia , García‐Barriuso Mónica , Ángeles Sánchez‐Anta María , Amich Francisco
Published: April 2008

The orchid flora of the Iberian Peninsula is relatively well known, but its biogeographical and diversity patterns have until now remained unanalysed. This work compares the richness of this flora with that of 27 other territories in different continents and at different latitudes, with the aim of establishing whether it is richer or poorer than might be expected. Latitude was found to be an excellent predictor of regional orchid species richness. With 122 taxa, the orchid flora of the Iberian Peninsula is more or less as diverse as that of other Mediterranean areas of similar latitude (e.g. France, Greece or Italy), but more diverse than other European or indeed North African orchid floras. In this study, the Iberian orchid species were assigned to eight monophyletic clades and the global distribution of these are mapped to establish continental affinities between the floras. A recent floristic account on the Iberian orchids was also used to assign the orchid taxa to habitats, and the relationship between the number of endemisms and their habitats was analysed. The patterns of endemism differed in different habitats. Very high levels of endemism were found in habitats peculiar to the Mediterranean Basin, indicating the relict status of its orchid flora.
Lectotypification of Rehmannia rupestris Hemsley (=Triaenophorarupestris (Hemsley) Solereder) (Scrophularaceae)
Authors: Li Xiao‐Dong , Li Jian‐Qiang
Published: April 2008

Rehmannia rupestris Hemsley (=Triaenophorarupestris (Hemsley) Solereder), described from three specimens, is lectotypified in this study.
Formulation of long‐acting nifedipine tablets influences the heart rate and sympathetic nervous system response in hypertensive patients
Authors: Brown Morris J. , Toal Corey B.
Published: April 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Pharmacokinetic and pharmacodynamics studies are usually carried out separately with theoretical linking or interpretations.

• The pharmacokinetics of short‐ vs. long‐acting formulations of nifedipine is well known, but the pharmacokinetics of different once‐a‐day formulations of nifedipine is generally not well known by the practising physician.

WHAT THIS STUDY ADDS

• This study provides practical patient‐based information linking pharmacokinetics to pharmacodynamics in one of the target populations of patients, those with hypertension, who might receive the two different drugs.

AIMS

The haemodynamic responses to nifedipine vary between short‐ and long‐acting formulations. However, the latter have not been compared despite marked differences in their constitution. Our 1‐month randomized, crossover study was designed to compare the 30‐mg osmotic, constant‐release nifedipine gastrointestinal therapeutic system (N‐GITS) with an encapsulated mini‐tablet Coracten XL.

METHODS

Forty‐four hypertensive patients aged 63 ± 7 years were studied. The formulation was changed on day 15 and (for a single dose) day 30. At days 0, 14, 15, 29 and 30, patients were monitored for 6 h after dosing, during which blood pressure (BP), heart rate (HR) and plasma levels of norepinephrine (NE) and nifedipine were measured. The primary outcome was the difference in plasma NE between formulations at the time of peak nifedipine level.

RESULTS

Systolic BP decreased rapidly after the first dose of Coracten, achieving nadir at 5 h. HR rose by 1.2 ± 8.8 beats min−1. After N‐GITS HR fell by 2.4 ± 7.7 beats min−1 (P = 0.159). Plasma NE was higher in the Coracten‐ (480 ± 38.3 pg ml−1) than N‐GITS‐treated patients (343 ± 75.0 pg ml−1) at the time of peak nifedipine concentrations (4 and 5 h, respectively) and their change from baseline was significantly (P = 0.0046) different. A similar difference between the drugs was seen again at days 15 and 30, at 5 h after switching formulations.

CONCLUSIONS

This study suggests that two different formulations of once‐daily nifedipine result in different BP and plasma NE responses, and that switching between formulations causes opposite effects upon the sympathetic nervous response to falling BP.
The addition of liposomal doxorubicin to bortezomib, thalidomide and dexamethasone significantly improves clinical outcome of advanced multiple myeloma
Authors: Ciolli Stefania , Leoni Franco , Casini Cinzia , Breschi Carla , Santini Valeria , Bosi Alberto
Published: April 2008

Relapsed/refractory myeloma has a poor outcome because of multi‐drug resistance, patient low‐performance status and toxicity of conventional chemotherapy. To improve results, standard chemotherapeutics and drugs targeting the microenvironment are applied at the same time. Bortezomib, by inhibiting proteasome function, may enhance chemosensitivity to other drugs and overcome drug‐resistance. Notably, doxorubicin and bortezomib may reciprocally increase their efficacy. Thus, to improve outcome whilst minimizing therapy‐related toxicity, liposomal doxorubicin was added to a bortezomib‐based combination. From January 2004, relapsed/refractory myeloma patients referred to our Institution received bortezomib 1·0 mg/m2 i.v. twice weekly for 2 weeks in a 28‐d cycle for up to six cycles, oral dexamethasone 24 mg with the standard scheduling and thalidomide 100 mg continuously (VTD). From January 2005, liposomal doxorubicin, 50 mg/m2 (30 mg/m2 for patients older than 75 years), was added on day 4 of each cycle [VTD plus Myocet (MyVTD)]. In total, 70 patients were treated: 28 received VTD and 42 MyVTD. Baseline demographic and clinical characteristics were similar between the two groups. Toxicity was manageable although more pronounced with MyVTD. The overall response rate (81% vs. 50%, P = 0·009), time to progression (19 vs. 11 months, P = 0·01) and progression‐free survival (15 vs. 8 months, P = 0·001) were significantly higher with MyVTD regimen, suggesting an improved quality of response.
‘Always the guiding hand’: parents' accounts of the long‐term implications of developmental co‐ordination disorder for their children and families
Authors: Stephenson E. A , Chesson R. A
Published: April 2008

Background  There has been little investigation of the long‐term implications of developmental co‐ordination disorder (DCD) and, particularly, its impact on families. This is despite the prevalence of the disorder (4.5% to 6%) of the child population, and the high rates of referral to occupational therapy departments. The study reported here was part of an evaluation of an innovative screening clinic for the assessment of children with DCD.

Methods  Within the case study approach of the evaluation, questionnaires, including open‐end questions, were sent to 70 families. All had attended the screening clinic 6 years earlier and had little subsequent contact with the occupational therapy service. Semi‐structured interviews were held with 12 mothers who volunteered to participate. These enabled specific issues raised in the questionnaires to be explored in greater depth. Interviews were audiotaped and full text transcripts produced for analysis.

Results  Over half the questionnaires were returned despite the length of time elapsed since hospital contact. Parents who responded reported a high persistence of problems in their children. Difficulties spanned motor and academic performance, emotional/behavioural responses and social interaction. Twenty‐eight children (80%) of respondents were reported as having difficulties in three or more areas. Bullying was a commonly identified problem. At interview mothers spoke at length about their experiences and reported feeling stressed and distressed. Mothers reported a lack of support and expressed feelings of isolation. They said that their time investment in their child with DCD had pronounced effects on themselves and other family members. Specifically they highlighted time spent fighting the system, primarily for educational support.

Conclusions  The study suggests a need for occupational therapists to reframe their current ideas regarding service provision, with improved support for families, increased interagency working and more service‐user involvement.
Lancet series on maternal and child undernutrition. Maternal and child undernutrition 1: global and regional exposures and health consequences
Authors: Reading Richard
Published: April 2008

.
 
Black R.E.,
Allen L.H.,
Bhutta Z.A.,
Caulfield L.E.,
De Onis M.,
Ezzati M.,
Mathers C.,
Rivera J. &
(
2008
)

,
371
,
243
–
260
.
 
DOI: 10.1016/S0140‐6736(07)61690‐0.
Maternal and child undernutrition 4: effective action at national level
Authors: Reading Richard
Published: April 2008

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Bryce J.,
Coitinho D.,
Darnton‐Hill I.,
Pelletier D.,
Pinstrup‐Andersen P. &
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2008
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371
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510
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526
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DOI: 10.1016/S0140‐6736(07)61694‐8.
GH and IGF‐I excess control contributes to blood pressure control: results of an observational, retrospective, multicentre study in 105 hypertensive acromegalic patients on hypertensive treatment
Authors: Colao Annamaria , Terzolo Massimo , Bondanelli Marta , Galderisi Maurizio , Vitale Giovanni , Reimondo Giuseppe , Ambrosio Maria Rosaria , Pivonello Rosario , Lombardi Gaetano , Angeli Alberto , Degli Uberti Ettore C.
Published: April 2008

Context  Approximately one‐third of patients with acromegaly have concomitant hypertension. The outcome of hypertension after treatment of acromegaly is unknown.

Objective  To evaluate the role of GH and IGF‐I control on systolic (SBP) and diastolic blood pressure (DBP) levels.

Patients  One hundred and five hypertensive patients (60 women, 45 men) with active disease receiving treatment for hypertension at their diagnosis of acromegaly.

Design  Observational, retrospective, multicentre.

Measurements  At diagnosis and after 24 months (median) of treatment we measured serum GH and IGF‐I levels, blood pressure levels, left ventricular (LV) mass index (LVMi), early‐to‐late mitral flow velocity (E/A, as a measure of diastolic function) and LV ejection fraction (LVEF, as a measure of systolic function).

Results  At the diagnosis of acromegaly, hypertension was mild in 41·1% and severe in 58·9%. Serum GH and IGF‐I levels did not differ in patients with mild or severe hypertension. After 24 months of treatment, all patients had a notable decrease in both GH and IGF‐I levels, and achieved significantly lower levels of DBP, heart rate and LVMi; 76 patients (71%) had achieved control of GH and IGF‐I levels. Only the patients with controlled acromegaly achieved significantly lower SBP levels and significantly improved cardiac systolic and diastolic function. A higher dose of antihypertensive drugs and/or an increased number of drugs to control hypertension were significantly greater in patients with uncontrolled (32·3%) than in those with controlled acromegaly (7·8%; P = 0·004).

Conclusion  Hypertensive patients with controlled acromegaly achieved improved control of hypertension and of cardiac diastolic and systolic function. The use of antihypertensive drugs was significantly less in patients achieving control of acromegaly.
Discriminative power of three indices of renal calcium excretion for the distinction between familial hypocalciuric hypercalcaemia and primary hyperparathyroidism: a follow‐up study on methods
Authors: Christensen Signe Engkjær , Nissen Peter H. , Vestergaard Peter , Heickendorff Lene , Brixen Kim , Mosekilde Leif
Published: April 2008

Background  Familial hypocalciuric hypercalcaemia (FHH) must be differentiated from primary hyperparathyroidism (PHPT) because prognosis and treatment differ. In daily practice this discrimination is often based on the renal calcium excretion or the calcium/creatinine clearance ratio (CCCR). However, the diagnostic performance of these variables is poorly documented.

Aim  To appraise the power of various simple biochemical variables to differentiate between FHH and PHPT using calcium sensing receptor (CASR) gene analysis and histopathological findings as gold standards.

Design  Follow‐up approach (direct design).

Materials  We included 54 FHH patients (17 males and 37 females, aged 18–75 years) with clinically significant mutations in the CASR gene and 97 hypercalcaemic patients with histologically verified PHPT (17 males and 80 females, aged 19–86 years). All PHPT patients became normocalcaemic following successful neck exploration.

Results  Based on receiver operating characteristic (ROC) curve analysis, the CCCR was only marginally better, as judged by the area under curve (AUC = 0·923 ± 0·021 (SE)), than the 24‐h calcium/creatinine excretion ratio (AUC = 0·903 ± 0·027) and the 24‐h calcium excretion (AUC = 0·876 ± 0·029). However, overlap performance analysis disclosed that the CCCR included fewer patients with PHPT together with the FHH patients than the other two variables at different cut‐off points. Based on the ROC curve, the optimal cut‐off point for diagnosing FHH using CCCR was < 0·0115, which yielded a diagnostic specificity of 0·88 and a sensitivity of 0·80. Overlap analysis revealed that a cut‐off point for CCCR at < 0·020 would sample 98% (53/54) of all patients with FHH and include 35% (34/97) of the PHPT patients.

Conclusion  Our results support the use of the CCCR as an initial screening test for FHH. We suggest a two‐step diagnostic procedure, where the first step is based on the CCCR with a cut‐off at < 0·020, and the second step is CASR gene analysis in patients with FHH or PHPT.
Changes in endothelial function and its association with plasma osteoprotegerin in hypothyroidism with exercise‐induced silent myocardial ischaemia
Authors: Guang‐da Xiang , Hui‐ling Sun , Jie Hou
Published: April 2008

Objective  Hypothyroidism is associated with an increased risk for cardiovascular disease. Exercise‐induced silent myocardial ischaemia (SI) is an early stage of coronary artery disease. Recently, many studies have shown that endothelial dysfunction is an early physiological event in atherosclerosis, and osteoprotegerin (OPG) acts as an important regulatory molecule in the vasculature. The aim of this study was to investigate the alteration of endothelial function and its association with plasma OPG in hypothyroidism with SI.

Methods  Forty‐eight female postmenopausal hypothyroid patients with normal rest electrocardiography (ECG) were selected. Of these, 19 cases had SI. Twenty healthy females without SI were selected as controls. High‐resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperaemia and after sublingual glyceryltrinitrate (GTN). Plasma OPG concentration was measured in duplicate by a sandwich enzyme‐linked immunosorbent assay (ELISA).

Results  Flow‐mediated arterial dilation (FMD) in the total hypothyroid group, the hypothyroidism with SI group and the hypothyroidism without SI group was 3·51 ± 0·62%, 3·20 ± 0·54% and 3·72 ± 0·60%, respectively, significantly lower than that in the controls (5·08 ± 0·61%) (P < 0·01). Compared with the hypothyroidism without SI group, FMD in the hypothyroidism with SI group was significantly lower (P < 0·05). Plasma OPG levels in the total hypothyroid group, patients with SI and patients without SI were significantly higher than in the control group (P < 0·05). Compared with patients without SI, OPG levels were significantly higher in patients with SI (P < 0·05). On multiple regression analysis, low density lipoprotein cholesterol (LDL‐C), lipoprotein (a) [Lp(a)], C‐reactive protein (CRP), OPG, TSH, free T3 (FT3) and thyroid peroxidase antibody (TPO‐Ab) were found to be significant factors that were associated with FMD. Logistic analysis also showed that LDL‐C, TSH, OPG, CRP and FMD were independently and significantly associated with SI in hypothyroidism.

Conclusion  Impaired endothelial function and increased levels of OPG exist in hypothyroid patients, especially those with SI. These findings support the growing concept that endothelial dysfunction may be associated with vascular disease, and subsequently elevated plasma OPG may have a role in the development of vascular dysfunction in hypothyroid patients.
Polymorphisms in the brain‐specific thyroid hormone transporter OATP1C1 are associated with fatigue and depression in hypothyroid patients
Authors: Van Der Deure Wendy M. , Appelhof Bente C. , Peeters Robin P. , Wiersinga Wilmar M. , Wekking Ellie M. , Huyser Jochanan , Schene Aart H. , Tijssen Jan G. P. , Hoogendijk Witte J. G. , Visser Theo J. , Fliers Eric
Published: April 2008

Introduction  Some hypothyroid patients continue to have significant impairments in psychological well‐being, despite adequate treatment with levothyroxine (LT4). T4 transport across the blood–brain barrier is one of the crucial processes for thyroid hormone action in the brain. OATP1C1, a thyroid hormone transporter expressed at the blood–brain barrier, is considered to play a key role in delivering serum T4 to the brain.

Objective  To examine whether polymorphisms in OATP1C1 are determinants of well‐being, neurocognitive functioning and preference for replacement therapy with a combination of LT4 and liothyronine (LT3).

Design and participants  We studied 141 patients with primary autoimmune hypothyroidism, adequately treated with LT4 monotherapy and participating in a randomized clinical trial comparing LT4 therapy with LT4–LT3 combination therapy.

Outcome measurements  Different questionnaires on well‐being and neurocognitive tests were performed at baseline. Serum thyroid parameters, OATP1C1‐intron3C > T, OATP1C1‐Pro143Thr and OATP1C1‐C3035T polymorphisms were determined.

Results  Allele frequencies of the OATP1C1 polymorphisms in patients with primary hypothyroidism were similar to those of healthy controls. Both the OATP1C1‐intron3C > T and the OATP1C1‐C3035T polymorphism, but not the OATP1C1‐Pro143Thr polymorphism, were associated with symptoms of fatigue and depression. OATP1C1 polymorphisms were not associated with measures of neurocognitive functioning or preference for combined LT4–LT3 therapy.

Conclusions  OATP1C1 polymorphisms are associated with fatigue and depression, but do not explain differences in neurocognitive functioning or appreciation of LT4–LT3 combination therapy. Future studies are needed to confirm these findings.
Long‐term basal and dynamic evaluation of hypothalamic–pituitary–adrenal (HPA) axis in acromegalic patients
Authors: Ronchi C. L. , Ferrante E. , Rizzo E. , Giavoli C. , Verrua E. , Bergamaschi S. , Lania A.G. , Beck‐Peccoz P. , Spada† A.
Published: April 2008

Objective  Long‐term effects of trans‐naso‐sphenoidal surgery (TNS) or long‐acting somatostatin analogs (SSA) on the function of hypothalamic–pituitary–adrenal (HPA) axis have been poorly investigated. Aim of this study was to evaluate HPA axis integrity during the follow‐up in patients with GH‐secreting pituitary adenomas and preserved HPA function post‐TNS or prior SSA.

Design and patients  This retrospective study investigated 36 acromegalic patients (16M and 20F, age: 47 ± 13 years), 20 of whom cured by TNS and 16 controlled by SSA therapy (12 previously operated and 4 in primary medical therapy), before and after long‐term follow‐up (median: 72 months, range: 12–240). No patient previously underwent radiotherapy.

Measurements  HPA function was studied by morning circulating cortisol and ACTH levels, 24‐h urinary free cortisol (UFC) and cortisol response to low‐dose short Synacthen test (LDSST, 1 µg) with a peak > 500 nmol/l as cut‐off for normal function.

Results  Serum basal cortisol, ACTH and UFC levels were in the normal range and did not significantly change over time. As far as the cortisol peak after LDSST is concerned, 12 patients (32%, 8 TNS and 4 SSA) developed biochemical hypoadrenalism. None of the patients in primary medical therapy showed cortisol peak < 500 nmol/l. No significant correlations between HPA axis deterioration and follow‐up duration, serum GH/IGF‐I levels, occurrence of other pituitary deficiencies, presence of secondary empty sella, changes in tumour or residual volume were observed.

Conclusions  The HPA axis function must be carefully monitored over the time by dynamic testing in all acromegalic patients, independently from the type of treatment.