bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic and temperature effects in spin-transfer switching
Authors: Cimpoesu Dorin , Pham Huy , Stancu Alexandru , Spinu Leonard
Published: December 2008

We have studied the dynamic switching triggered by spin angular momentum transfer in a pulsed current of a spin-valve-type trilayer structure, and its dependence on thermal effects. In order to determine the current pulse parameters, where fast and stable switching can be achieved, we have studied the magnetization’s dynamics properties as a function of applied current pulse amplitude and shape, waiting time, and initial orientation, and also as a function of the Gilbert damping constant. The magnetic layer is assumed to be single domain, ellipsoid shaped. In this paper also we present the thermal fluctuation effects on the switching behavior. The model is based on the Landau–Lifshitz–Gilbert equation and the stochastic Landau–Lifshitz–Gilbert equation with a spin-transfer term included, which are numerically integrated.
Vinylphosphine-borane: Synthesis, gas phase infrared spectroscopy, and quantum chemical vibrational calculations
Authors: Khater Brahim , Guillemin Jean-Claude , Benidar Abdessamad , Bégué Didier , Pouchan Claude
Published: December 2008

Both experimental and theoretical investigations are reported on the infrared spectrum of vinylphosphine-borane (CH2=CHPH2⋅BH3), a donor-acceptor complex. The gas phase infrared spectra (3500–600 cm−1) have been recorded at 0.5 cm−1 resolution. This first primary α,β-unsaturated phosphine-borane synthesized up to now is kinetically very unstable in the gas phase and decomposes rapidly into two fragments: the free vinylphosphine CH2=CHPH2 and the monoborane BH3 which dimerizes to form the more stable diborane B2H6. Spectra of free CH2=CHPH2 and B2H6 compounds were also recorded to assign some vibration modes of the complex in very dense spectral regions. The analysis was completed by carrying out quantum mechanical calculations by density functional theory method at the B3LYP/6-31+G∗∗ level. Anharmonic frequencies and infrared intensities of the two predicted gauche and syn conformers of the vinylphosphine-borane complex were calculated in the 3500–100 cm−1 region with the use of a variational approach, implemented in the P_ANHAR_V1.2 code. Because of the relatively weak interaction between the vinylphosphine and the monoborane, the vibrations of the complex can easily be subdivided into modes localized in the CH2=CHPH2 and BH3 moieties and into “intermolecular” modes. Localized modes are unambiguously correlated with the modes of the isolated monomers. Therefore, they are described in terms of the monomer vibrations, and the complexation shifts are defined as Δν=νcomplex–νmonomer to make the effect of the complexation precise on each localized mode. In this objective, anharmonic frequencies and infrared intensities of the BH3 monomer and the stable gauche and syn conformers of the free vinylphosphine were obtained at the same level of theory. In the gas phase, only the syn form of the complex was observed and assigned. All theoretically predicted frequencies and complexation shifts in magnitude and direction are in good agreement with experiment. By infrared spectroscopy assisted by quantum chemical calculations, the consequences of the complexation of an α,β-unsaturated phosphine by borane on the physicochemical properties of the formed 12-atom complex have been efficiently evaluated.
Reduced boron lateral ion channeling in very short p-channel transistors by switching from ⟨110⟩ to ⟨100⟩ channel orientation
Authors: Lau W. S. , Yang Peizhen , Ho V. , Lim B. K. , Siah S. Y. , Chan L.
Published: December 2008

The on-current of p-channel transistors fabricated on (100) Si substrate can be easily increased by switching from ⟨110⟩ to ⟨100⟩ channel orientation because of faster hole transport. In this paper, we pointed out that there is also a reduction in the gate-to-source/drain overlap, resulting in an increase in the effective channel length for p-channel transistors. Our experimental observation can be explained by a reduction in boron lateral ion channeling due to this switch.
Oxygen deficiency as a driving force for metamagnetism and large low field magnetocaloric effect in La0.7Ca0.3−xSrxMnO3−δ manganites
Authors: Ulyanov A. N. , Kim J. S. , Kang Y. M. , Yoo D. G. , Yoo S. I.
Published: December 2008

We report the importance of metamagnetism for the giant magnetocaloric effect in lanthanum manganites and the key role of oxygen deficiency for this phenomenon. It is found that La0.7Ca0.3−xSrxMnO3−δ samples with x=0.0, 0.025, 0.05, 0.075, 0.1, and 0.125 are orthorhombic (O) phase, while those with x=0.15, 0.175, 0.2, and 0.3 are rhombohedral (R) phase at room temperature. The samples possess relatively high oxygen deficiency δ. With increasing x, the oxygen content increases from about 2.92 to 2.94 in the O phase and from 2.93 to 2.97 in the R phase, while it decreases in the vicinity of the O-R phase transition. The Curie temperature increases with increasing x in both the structural phases and shows a positive jump around the O-R phase transition. The x=0 sample shows S-shape magnetization, which is typical for metamagnetic materials. The S shape is continuously suppressed with increase in Sr and disappears for x≥0.075. Interestingly, the magnetic entropy change, adiabatic temperature change, and refrigerant capacity achieved for the present samples are about 20%–50% larger than those previously reported for manganites prepared using different processing routes. The large magnetocaloric effect in the present samples originates from the sharp change in magnetization with respect to temperature at the Curie temperature and the presence of S-shape magnetization near this transition temperature caused by the oxygen deficiency.
Ferromagnetic structurally disordered ZnO implanted with Co ions
Authors: Potzger K. , Zhou Shengqiang , Xu Qingyu , Shalimov A. , Groetzschel R. , Schmidt H. , Mücklich A. , Helm M. , Fassbender J.
Published: December 2008

We present superparamagnetic clusters of structurally highly disordered Co–Zn–O created by high fluence Co ion implantation into ZnO (0001) single crystals at low temperatures. This secondary phase cannot be detected by common x-ray diffraction but is observed by high-resolution transmission electron microscopy. In contrast to many other secondary phases in a ZnO matrix, it induces low-field anomalous Hall effect and is thus a candidate for magnetoelectronics applications.
Multilayered solid-state organic laser for simultaneous multiwavelength oscillations
Authors: Yamashita K. , Arimatsu A. , Takeuchi N. , Takayama M. , Oe K. , Yanagi H.
Published: December 2008

This paper describes an organic dye-doped polymeric laser with a multilayered structure of active waveguides. Using the technique of photonanoimprint lithography, organic active-waveguide layers with distributed-feedback cavities and a polymeric intermediate cladding layer were stacked on a silica substrate. Under optical pumping, lasing oscillations at 427 and 636 nm, which correspond to the Bragg reflection wavelengths in the respective active waveguides, were simultaneously observed. The fabrication scheme presented here is expected to be a promising technology for the development of compact multicolor laser sources.
β-Catenin downregulation attenuates ischemic cardiac remodeling through enhanced resident precursor cell differentiation
Authors: Zelarayán Laura C. , Noack Claudia , Sekkali Belaid , Kmecova Jana , Gehrke Christina , Renger Anke , Zafiriou Maria-Patapia , van der Nagel Roel , Dietz Rainer , de Windt Leon J. , Balligand Jean-Luc , Bergmann Martin W.
Published: December 2008

We analyzed the effect of conditional, α
MHC
-dependent genetic β-catenin depletion and stabilization on cardiac remodeling following experimental infarct. β-Catenin depletion significantly improved 4-week survival and left ventricular (LV) function (fractional shortening: CT
Δex3–6
: 24 ± 1.9%; β-
cat
Δex3–6
: 30.2 ± 1.6%,
P
< 0.001). β-Catenin stabilization had opposite effects. No significant changes in adult cardiomyocyte survival or hypertrophy were observed in either transgenic line. Associated with the functional improvement, LV scar cellularity was altered: β-catenin-depleted mice showed a marked subendocardial and subepicardial layer of small cTnT
pos
cardiomyocytes associated with increased expression of cardiac lineage markers Tbx5 and GATA4. Using a Cre-dependent
lacZ
reporter gene, we identified a noncardiomyocyte cell population affected by α
MHC
-driven gene recombination localized to these tissue compartments at baseline. These cells were found to be cardiac progenitor cells since they coexpressed markers of proliferation (Ki67) and the cardiomyocyte lineage (αMHC, GATA4, Tbx5) but not cardiac Troponin T (cTnT). The cell population overlaps in part with both the previously described c-kit
pos
and stem cell antigen-1 (Sca-1)
pos
precursor cell population but not with the Islet-1
pos
precursor cell pool. An
in vitro
coculture assay of highly enriched (>95%) Sca-1
pos
cardiac precursor cells from β-catenin-depleted mice compared to cells isolated from control littermate demonstrated increased differentiation toward α-actin
pos
and cTnT
pos
cardiomyocytes after 10 days (CT
Δex3–6
: 38.0 ± 1.0% α-actin
pos
; β-
cat
Δex3–6
: 49.9 ± 2.4% α-actin
pos
,
P
< 0.001). We conclude that β-catenin depletion attenuates postinfarct LV remodeling in part through increased differentiation of GATA4
pos
/Sca-1
pos
resident cardiac progenitor cells.
The archaebacterial origin of eukaryotes
Authors: Cox Cymon J. , Foster Peter G. , Hirt Robert P. , Harris Simon R. , Embley T. Martin
Published: December 2008

The origin of the eukaryotic genetic apparatus is thought to be central to understanding the evolution of the eukaryotic cell. Disagreement about the source of the relevant genes has spawned competing hypotheses for the origins of the eukaryote nuclear lineage. The iconic rooted 3-domains tree of life shows eukaryotes and archaebacteria as separate groups that share a common ancestor to the exclusion of eubacteria. By contrast, the eocyte hypothesis has eukaryotes originating within the archaebacteria and sharing a common ancestor with a particular group called theCrenarchaeotaor eocytes. Here, we have investigated the relative support for each hypothesis from analysis of 53 genes spanning the 3 domains, including essential components of the eukaryotic nucleic acid replication, transcription, and translation apparatus. As an important component of our analysis, we investigated the fit between model and data with respect to composition. Compositional heterogeneity is a pervasive problem for reconstruction of ancient relationships, which, if ignored, can produce an incorrect tree with strong support. To mitigate its effects, we used phylogenetic models that allow for changing nucleotide or amino acid compositions over the tree and data. Our analyses favor a topology that supports the eocyte hypothesis rather than archaebacterial monophyly and the 3-domains tree of life.
One-step assembly in yeast of 25 overlapping DNA fragments to form a complete synthetic
Mycoplasma genitalium
genome
Authors: Gibson Daniel G. , Benders Gwynedd A. , Axelrod Kevin C. , Zaveri Jayshree , Algire Mikkel A. , Moodie Monzia , Montague Michael G. , Venter J. Craig , Smith Hamilton O. , Hutchison Clyde A.
Published: December 2008

We previously reported assembly and cloning of the synthetic
Mycoplasma genitalium
JCVI-1.0 genome in the yeast
Saccharomyces cerevisiae
by recombination of six overlapping DNA fragments to produce a 592-kb circle. Here we extend this approach by demonstrating assembly of the synthetic genome from 25 overlapping fragments in a single step. The use of yeast recombination greatly simplifies the assembly of large DNA molecules from both synthetic and natural fragments.
The Multiple Roles of Cohesin in Meiotic Chromosome Morphogenesis and Pairing
Authors: Brar Gloria A. , Hochwagen Andreas , Ee Ly-sha S. , Amon Angelika
Published: December 2008

Sister chromatid cohesion, mediated by cohesin complexes, is laid down during DNA replication and is essential for the accurate segregation of chromosomes. Previous studies indicated that, in addition to their cohesion function, cohesins are essential for completion of recombination, pairing, meiotic chromosome axis formation, and assembly of the synaptonemal complex (SC). Using mutants in the cohesin subunit Rec8, in which phosphorylated residues were mutated to alanines, we show that cohesin phosphorylation is not only important for cohesin removal, but that cohesin's meiotic prophase functions are distinct from each other. We find pairing and SC formation to be dependent on Rec8, but independent of the presence of a sister chromatid and hence sister chromatid cohesion. We identified mutations in REC8 that differentially affect Rec8's cohesion, pairing, recombination, chromosome axis and SC assembly function. These findings define Rec8 as a key determinant of meiotic chromosome morphogenesis and a central player in multiple meiotic events.
Disruption of Smad4 in Mouse Epidermis Leads to Depletion of Follicle Stem Cells
Authors: Yang Leilei , Wang Lijuan , Yang Xiao
Published: December 2008

Follicle stem cells (SCs) residing in the bulge region of a hair follicle (HF) can give rise to multiple lineages during the hair cycle and wound healing. The activation and self-renewal of follicle SCs must be tightly regulated to maintain the HF and epidermal homeostasis. Here we show that, in young mice, disruption of epidermal Smad4, the common mediator of transforming growth factor-β (TGF-β) signaling, stimulated the activation of follicle SCs, leading to hyperplasia of interfollicular epidermis (IFE), HFs, and sebaceous glands (SGs). Increased proliferation of follicle SCs ultimately exhausted the SC niche, indicated by the loss of bromodeoxyuridine (BrdU) label–retaining cells (LRCs), loss of keratin 15 (K15), and CD34 expression. In addition, the colony-forming efficiency of Smad4 mutant keratinocytes was significantly decreased. Increased nuclear localization of β-catenin and increased expression of c-Myc were correlated with the overactivation and depletion of follicle SCs. We concluded that Smad4 plays a pivotal role in follicle SC maintenance.
Teenage Contraception
Authors: Wilson Anna
Published: December 2008

The UK has the highest teenage birth and abortion rates in Europe. Although the teenage birth rate is falling, there is an upward trend in teenage abortion. The conception statistics of the Office of National Statistics are used for monitoring progress towards the teenage pregnancy strategy's target, which is to halve England's under-18 conception rate by 2010, from a 1998 baseline.
Historical and contemporary selection of teleost MHC genes: did we leave the past behind?
Authors: Wegner K. M.
Published: December 2008

The extreme polymorphism of antigen‐presenting genes of the major histocompatibility complex (MHC) has spurred intense research unparalleled for any other gene family. This applies also to teleosts where sequence information is available for 3559 MHC class I and class II allelic variants from 137 species. This review summarizes current knowledge on the origin and maintenance of diversity at classical MHC loci. Most studies identified positive selection (i.e. elevated rates of non‐synonymous over synonymous substitutions, dN/dS) as a sign of balancing selection. A meta‐analysis on nine species with sufficient numbers of class I and class II sequences revealed that recombination rate and intensity of positive selection were positively correlated, suggesting that recombination and gene conversion played a significant role in shaping the allelic repertoire. Processes that create diversity over long timescales need to be complemented by contemporary balancing selection, either through overdominance or frequency‐dependent selection, in order to explain the high allelic diversity observed today. While some evidence for overdominance exists for a few taxa (mainly salmonids) by correlating parasite infection data or survival to MHC genotypes, field or experimental data on negative frequency‐dependent selection are lacking altogether, even though some fish species are particularly suitable as model systems. Theoretical predictions suggest that negative frequency‐dependent selection is necessary to maintain the existing polymorphism. Hence, future empirical studies should focus on detecting signals that differentiate between mechanisms of contemporary selection rather than repeatedly showing historical selection events.
Gyrodactylus salarisinfecting allopatric Arctic charrSalvelinus alpinusfry: an experimental study of host survival
Authors: Winger A. C. , Primicerio R. , Kristoffersen R. , Siikavuopio S. I. , Knudsen R.
Published: December 2008

Artificially reared Arctic charrSalvelinus alpinusfry (post yolk‐sac stage) from Skibotnelva in northern Norway were exposed to infection with the monogenean ectoparasiteGyrodactylus salaristo determine if the parasite caused mortality in fry. About 95% of the fry became infected within the first week post‐exposure, and at the end of the experiment (77 days) all fry carried the parasite. Mortality rate was significantly higher in the groups of infected fry than in the uninfected control groups, and when the experiment was terminatedc.30% of the infected and 8% of the uninfected fish had died.Gyrodactylus salarishad a pronounced negative effect upon fry survival and caused an additive host mortality. Moreover, the concurrent temporal changes in parasite intensities and aggregation indicated that the parasite‐induced host mortality was density dependent.
Simaomicin α, a polycyclic xanthone, induces G1 arrest with suppression of retinoblastoma protein phosphorylation
Authors: Koizumi Yukio , Tomoda Hiroshi , Kumagai Ayako , Zhou Xiao‐ping , Koyota Souichi , Sugiyama Toshihiro
Published: December 2008

Recent progress in cancer biology research has shown that abnormal proliferation in tumor cells can be attributed to aberrations in cell cycle regulation, especially in G1 phase. During the course of searching for microbial metabolites that affect cell cycle distribution, we have found that simaomicin α, a polycyclic xanthone antibiotic, arrests the cell cycle at G1 phase. Treatment of T‐cell leukemia Jurkat cells with 3 nM simaomicin α induced an increase in the number of cells in G1 and a decrease in those in G2–M phase. Cell cycle aberrations induced by simaomicin α were also detected in colon adenocarcinoma HCT15 cells. Simaomicin α had antiproliferative activities in various tumor cell lines with 50% inhibitory concentration values in the range of 0.3–19 nM. Furthermore, simaomicin α induced an increase in cellular caspase‐3 activity and DNA fragmentation, indicating that simaomicin α promotes apoptosis. The retinoblastoma protein phosphorylation status of simaomicin α‐treated cell lysate was lower than that of control cells, suggesting that the target molecule of simaomicin α is in a pathway upstream of retinoblastoma protein phosphorylation. In the course of evaluating polycyclic xanthone antibiotics structurally related to simaomicin α, we also found that cervinomycin A1 stimulated accumulation of treated cells in G1 phase. These results indicate that the polycyclic xanthones, including simaomicin α and cervinomycin A1, may be candidate cancer chemotherapeutic agents. (Cancer Sci 2009; 100: 322–326)
Age‐dependent quantitative trait loci affecting growth traits in Scottish Blackface sheep
Authors: Hadjipavlou G. , Bishop S. C.
Published: December 2008

To dissect age‐dependent quantitative trait loci (QTL) associated with growth and to examine changes in QTL effects over time, the Gompertz growth model was fitted to longitudinal live weight data on 788 Scottish Blackface lambs from nine half‐sib families. QTL were mapped for model parameters and weekly live weights and growth rates using microsatellite markers on chromosomes 1, 2, 3, 5, 14, 18, 20 and 21. QTL significance (using α = 0.05 chromosome‐wide significance thresholds, unless otherwise stated) varied with age, and those for growth rate occurred earlier than equivalent QTL for live weight. A chromosome 20 QTL for growth rate was significant from 4 to 9 weeks (maximum significance at 6 weeks) and for maximum growth rate. For live weight, this QTL was significant from 8 to 16 weeks (maximum significance at 12 weeks). A nominally significant chromosome 14 QTL was detected for growth rates from birth to week 2 in the same families and location as an 8‐week weight QTL. In addition, at the same position on chromosome 14, a QTL was significant for growth rate for 17–28 weeks (maximum significance at 24 weeks). A chromosome 3 QTL was significant for weights at early ages (birth to week 4) and a growth rate QTL on chromosome 18 was significant from 8 to 12 weeks. Fitting growth curves allowed the combination of information from multiple measurements into a few biologically meaningful variables, and the detection of growth QTL that were not observed from analyses of raw weight data. These QTL describe distinct parts of an animal’s growth curve trajectory, possibly enabling manipulation of this trajectory.
Access to prescribing information for paediatric medicines in the USA: post‐modernization
Authors: Young Larissa , Lawes Francis , Tordoff June , Norris Pauline , Reith David
Published: December 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Children have reduced access to medicines because of inadequate prescribing information and paucity of suitable formulations.

• The USA has implemented a series of measures designed to improve the licensing of medicines for children, which has resulted in an increase in the number of studies and the number of patients studied in investigational trials of medicines in children.

• These measures have increased the number of targeted medicines that have had their labelled use extended to children.

WHAT THIS STUDY ADDS

• Information in the Physicians' Desk Reference did not indicate that there was an improvement in overall access to, and prescribing information about, drugs in the paediatric population in the USA over the time period 1998–2007.

AIMS

The aims of the present study were to examine the Physicians' Desk Reference (PDR) for changes in the listing of medicines licensed for children in the USA over a 10‐year period (1998–2007).

METHODS

The USA PDR was used to identify products listed in 1998, 2002 and 2007. Information about generic name (active agent), salt, strength, brand name, suitability of formulation, paediatric licensing information and the lowest age of licensing was extracted. Prescription products were collapsed down to chemical entities/fixed‐dose combinations.

RESULTS

Of the prescription entities listed in the PDR, 538 (55.9%), 488 (54.3%) and 394 (51.3%) were licensed for children in 1998, 2002 and 2007, respectively. There was a 39% decrease in the number of entities licensed for the newborn and a 34% decrease for children aged 2–6 years between 1998 and 2007. Formulations suitable for children were listed for 611 (63.4%), 550 (61.2%) and 430 (60.6%), respectively. Prescription entities with both a suitable oral formulation and licensing for children numbered 161 (16.7%), 148 (16.5%) and 100 (14.1%) in 1998, 2002 and 2007, respectively.

CONCLUSIONS

The listings in the PDR suggest that overall access to prescribing information about drugs in the paediatric population has not shown an increase over the decade. This particularly affected the neonatal age group.
CpG-oligodeoxynucleotides stimulate immunoglobulin A secretion in intestinal mucosal B cells
Authors: Blaas S H , Stieber-Gunckel M , Falk W , Obermeier F , Rogler G
Published: December 2008

Bacterial DNA motifs (such as CpG-oligodeoxynucleotides: CpG-ODN) induce innate immune responses via binding to Toll-like-receptor-9 (TLR-9). In murine intestinal mucosa treatment with CpG-ODN worsens chronic intestinal inflammation, whereas it prevents or ameliorates colitis when given in a prophylactic setting. In tonsils B cells have been reported to express TLR-9, especially after activation. Whether B cells in the human intestinal mucosa also express TLR-9 and whether their function can be influenced by CpG-ODN is, so far, unknown. Mucosal B cells were isolated according to a new protocol from surgical specimens of patients with inflammatory bowel disease and from controls by collagenase digestion followed by magnetic cell sorting using anti-CD19 antibody armed magnetic beads. TLR-9 mRNA and protein expression were quantified by real-time polymerase chain reaction (PCR) and Western blot, respectively. Immunoglobulin A (IgA) secretion was measured by enzyme-linked immunosorbent assay after stimulation of isolated B cells with CpG-ODN, control GpC-ODN or lipopolysaccharide (LPS). Flow cytometric analysis of the isolated lamina propria mononuclear cells showed a purification of 73% (±22%) CD19+ cells. By quantitative reverse transcription–PCR and by Western blot TLR-9 expression in this cell population was evident. IgA secretion was increased significantly by CpG-ODN incubation compared with GpC-ODN and LPS. Compared with unstimulated controls, CpG-ODN up-regulated IgA secretion to 139% (±21%). These data demonstrate that CD19+ mucosal B cells express TLR-9 and secrete increased levels of IgA upon stimulation with CpG-ODN, indicating an additional link between adaptive and innate intestinal immune responses.
High-affinity human leucocyte antigen class I binding variola-derived peptides induce CD4+ T cell responses more than 30 years post-vaccinia virus vaccination
Authors: Wang M , Tang S T , Lund O , Dziegiel M H , Buus S , Claesson M H
Published: December 2008

Interferon-γ secreting T lymphocytes against pox virus-derived synthetic 9-mer peptides were tested by enzyme-linked immunospot in peripheral blood of individuals vaccinated with vaccinia virus more than 30 years ago. The peptides were characterized biochemically as high-affinity human leucocyte antigen (HLA) class I binders (KD ≤ 5 nM). However, five of the individuals tested did not show typical CD8+ T cell-mediated HLA class I-restricted responses. Instead, these donors showed CD4+ T cell-dependent responses against four of a total of eight antigenic 9-mer peptides discovered recently by our group. These latter responses were blocked specifically in the presence of anti-HLA class II antibody. We conclude that long-lived memory responses against pox virus-derived 9-mer peptides, with high binding affinity for HLA class I molecules, are mediated in some cases by CD4+ T cells and apparently restricted by HLA class II molecules.
Aetiology of cirrhosis of the liver has an impact on survival predicted by the Model of End‐stage Liver Disease score
Authors: Angermayr B. , Luca A. , König F. , Bertolini G. , Ploner M. , Gridelli B. , Ulbrich G. , Reiberger T. , Bosch J. , Peck‐Radosavljevic M.
Published: December 2008

Background  Originally, aetiology of liver disease has been incorporated into the computation of the Model of End‐stage Liver Disease (MELD) score. Clinical observations prompted us to hypothesize that patients with viral and alcoholic cirrhosis may differ in predicted survival rates. Until now, no large representative studies evaluated the impact of aetiology on long‐term survival predicted by the Child–Pugh and MELD scores.

Materials and methods  Four hundred and ninety‐three patients who underwent transjugular intrahepatic portosystemic shunt implantation in Vienna, Austria, and Palermo, Italy, were included in this retrospective study. The main analyses were a logistic regression model and a Cox proportional hazards regression model calculating the interaction of the aetiology with the scores.

Results  Both groups had similar survival rates (median 1377 and 1721 days for viral and alcoholic cirrhosis, respectively; P = 0.58), but patients with viral cirrhosis had significantly lower MELD scores (P = 0.002). In the Cox analysis, aetiology had a significant impact on the prediction of overall survival by MELD score. For 3‐month survival, MELD score was adequately predictive for both groups. For 1‐year survival, aetiology had a significant impact on survival, indicating that patients with identical scores but different aetiologies differed in survival rates. When stratifying patients into high‐ and low‐risk patients (MELD < 16 vs. MELD ≥ 16), aetiology of cirrhosis had no impact on the predictive value for low‐risk patients; high‐risk‐patients (MELD ≥ 16) with viral cirrhosis had significantly lower survival rates than patients with alcoholic cirrhosis and identical scores. With regard to Child–Pugh Score, no significant differences between the two patient groups and in the prediction of 3‐month and 1‐year survival could be observed.

Conclusions  Our study suggests that aetiology of cirrhosis has an impact on 1‐year survival predicted by the MELD score. This becomes more apparent in patients with advanced stage of liver disease (MELD ≥ 16). Since MELD score is used for ranking patients for liver transplantation and waiting times are regularly longer than 3 months, our observations suggest that with increasing time on the waiting list and severity of disease, patients with viral cirrhosis may have a disadvantage in the current allocation policy.
Measurement of nasal nitric oxide: evaluation of six different sampling methods
Authors: De Winter–de Groot K. M. , Van Der Ent C. K.
Published: December 2008

Background  Specific guidelines are developed for the measurement of bronchial FENO, however, nasal nitric oxide (nNO) measurement is not standardised yet, resulting in divergent nNO values. This study compares six different sampling methods for nNO as described in the literature, to analyse their outcome and short term and long term reproducibility.

Design  nNO concentrations were measured in 38 healthy subjects. Each subject performed nNO measurements during tidal breathing (nNO‐TB), single breath quiet exhalations (nNO‐QE), QE with oral exhalation against a resistance (nNO‐QE + R), breath holding (nNO‐BH) and during single‐breath humming exhalations at 128 and 440 Hz (nNO‐HE128 and nNO‐HE440, respectively). To assess short term and long term reproducibility all manoeuvres were repeated after one and 24 h.

Results  Lowest values were found during quiet exhalation (mean nNO‐QE was 364 p.p.b., SEM 27). Methods in which there is turbulence of nasal flow (as in TB, HE128 and HE440) result in higher nNO levels. Highest values were found in methods with decreased nasal flow [when there is no nasal flow as in BH or when the velum is closed as in QE + R: mean nNO 763 p.p.b. (SEM 61)]. NNO during humming at 440 Hz was significantly higher than at 128 Hz (P < 0·01). The within‐subject coefficient of variation of repeated measurements was lowest during humming and breath holding, 3·4 and 3·8%, respectively. Concerning short term and long term reproducibility, best agreement is reached with humming and second best with breath holding.

Conclusions  Different methods result in different levels and reproducibility of nNO. In regard to this, methods of humming and breath holding are recommended for standardised measurement of nasal NO.
Latitudinal trends in Spartina alterniflora productivity and the response of coastal marshes to global change
Authors: KIRWAN MATTHEW L. , GUNTENSPERGEN GLENN R. , MORRIS JAMES T.
Published: December 2008

Marshes worldwide are actively degrading in response to increased sea level rise rates and reduced sediment delivery, though the growth rate of vegetation plays a critical role in determining their stability. We have compiled 56 measurements of aboveground annual productivity for Spartina alterniflora, the dominant macrophyte in North American coastal wetlands. Our compilation indicates a significant latitudinal gradient in productivity, which we interpret to be determined primarily by temperature and/or the length of growing season. Simple linear regression yields a 27 g m−2 yr−1 increase in productivity with an increase of mean annual temperature by 1 °C. If temperatures warm 2–4 °C over the next century, then marsh productivity may increase by 10–40%, though physiological research suggests that increases in the north could potentially be offset by some decreases in the south. This increase in productivity is roughly equivalent to estimates of marsh lost due to future sea level change. If a warming‐induced stimulation of vegetation growth will enhance vertical accretion and limit erosion, then the combined effects of global change may be to increase the total productivity and ecosystem services of tidal wetlands, at least in northern latitudes.
Does deep soil N availability sustain long‐term ecosystem responses to elevated CO2?
Authors: McKINLEY DUNCAN C. , ROMERO JULIO C. , HUNGATE BRUCE A. , DRAKE BERT G. , MEGONIGAL JAMES P.
Published: December 2008

A scrub‐oak woodland has maintained higher aboveground biomass accumulation after 11 years of atmospheric CO2 enrichment (ambient +350 μmol CO2 mol−1), despite the expectation of strong nitrogen (N) limitation at the site. We hypothesized that changes in plant available N and exploitation of deep sources of inorganic N in soils have sustained greater growth at elevated CO2. We employed a suite of assays performed in the sixth and 11th year of a CO2 enrichment experiment designed to assess soil N dynamics and N availability in the entire soil profile. In the 11th year, we found no differences in gross N flux, but significantly greater microbial respiration (P≤0.01) at elevated CO2. Elevated CO2 lowered extractable inorganic N concentrations (P=0.096) considering the whole soil profile (0–190 cm). Conversely, potential net N mineralization, although not significant in considering the entire profile (P=0.460), tended to be greater at elevated CO2. Ion‐exchange resins placed in the soil profile for approximately 1 year revealed that potential N availability at the water table was almost 3 × greater than found elsewhere in the profile, and we found direct evidence using a 15N tracer study that plants took up N from the water table. Increased microbial respiration and shorter mean residence times of inorganic N at shallower depths suggests that enhanced SOM decomposition may promote a sustained supply of inorganic N at elevated CO2. Deep soil N availability at the water table is considerable, and provides a readily available source of N for plant uptake. Increased plant growth at elevated CO2 in this ecosystem may be sustained through greater inorganic N supply from shallow soils and N uptake from deep soil.
Single ability among activities of daily living as a predictor of agitation
Authors: Lin Li‐Chan , Wu Shiao‐Chi , Kao Chieh‐Chun , Tzeng Yu‐Ling , Watson Roger , Tang Sai‐Hung
Published: December 2008

Aims.  The aims of this study were to investigate whether the interaction effect between restraint and functional ability, and single ability during activities of daily living can predict agitation among residents with dementia.

Background.  Agitated behaviour is one of the most common symptoms of dementia and might endanger the patients themselves, caregivers and institutions. However, the prevalence of problem behaviours and its associated factors at long‐term care facilities in Taiwan are less understood.

Design.  A direct observation was used to observe the agitated behaviours of residents with dementia in special care units.

Methods.  Residents of dementia special care units who were diagnosed with dementia in eight long‐term care facilities were recruited. Measurements included: demographic data, the Barthel Index, the Mini‐Mental State Examination and the Cohen‐Mansfield Agitation Inventory.

Results.  The number of subjects who were identified with problem behaviours was 163 (43·5%). Significant differences in sex, being restrained, restrained time, age, family visits, functional status and mental status were found between the agitated and non‐agitated groups. However, mental status, family visits, walking ability, being restrained and getting in and off toilet were five independent factors associated with agitated behaviours after controlling for all other factors.

Conclusions.  It is recommended that strategies be constructed to encourage the family to periodically visit older residents and to develop restraint‐free environments in long‐term care facilities.

Relevance to clinical practice.  Residents with dementia require significant daily living support and behaviour management as their illness progress.
Coronary heart disease patients’ perception of their symptoms and sense of control are associated with their quality of life three years following hospital discharge
Authors: Lau‐Walker Margaret O , Cowie Martin R , Roughton Michael
Published: December 2008

Background.  Recent intervention studies have attempted to address cardiac rehabilitation patients’ illness beliefs to improve care. Their findings were mainly limited to short‐term behaviour changes such as return to work or attendance on rehabilitation programmes. Evidence about what aspects of the patients’ illness beliefs influence long‐term quality of life in cardiac rehabilitation remains sparse.

Objective.  To examine the association between coronary heart disease patients’ illness beliefs and their quality of life three years after hospital discharge.

Design.  A longitudinal prospective survey.

Methods.  Coronary heart disease patients (n = 253) completed validated questionnaires at three points. Patients’ illness beliefs were measured twice: before hospital discharge and nine months after discharge – using the Illness Perception Questionnaire. Quality of life was assessed as the outcome measure at three years after discharge, using the Health Survey SF36v2 questionnaire. Demographic, illness characteristics and cardiac rehabilitation attendance were also assessed.

Results.  Two multiple regression analyses were performed with each of the SF36v2 physical and mental health summary scores as outcome variables. Analysis of baseline data showed 43% of the variance in the physical health summary score at three years was accounted for by a perceived lower number of symptoms, belief that the illness was controllable, admission as an emergency and no previous history of cardiac illness; 22% of the variance in the mental health summary score was accounted for by perceived lower number of symptoms and no previous history of cardiac illness. Repeat analysis using the data collected nine months after discharge showed similar findings.

Conclusion.  Coronary heart disease patients’ perception of their symptoms and sense of control at time of discharge were significantly associated with their quality of life three years after discharge.

Relevance to clinical practice.  This study promotes the use of the assessment of patients’ illness beliefs as a routine practice to improve care.
Predictors of sexual abstinence behaviour in Taiwanese adolescents: a longitudinal application of the transtheoretical model
Authors: Wang Ruey‐Hsia , Cheng Chung‐Ping , Chou Fan‐Hao
Published: December 2008

Aims and objectives.  To understand (1) the change of stage of changes, self‐efficacy, decisional balance and processes of change for sexual abstinence behaviour across a 15‐month interval, (2) relations of baseline stage of changes, self‐efficacy, decisional balance and processes of change to follow‐up stage of changes for sexual abstinence and (3) the important predictors of follow‐up stage of changes and transition of stage of changes for sexual abstinence behaviour.

Background.  Examining factors of sexual abstinence behaviour among adolescents can provide useful information in designing sexual abstinence intervention programmes.

Design.  This study applied a transtheoretical model and used a longitudinal design.

Method.  Anonymous questionnaires were administered to 281 participants at baseline and 15‐month follow‐up.

Results.  In summary, 46·3% (n = 130) of the participants were in the same stage, 30·2% (n = 85) regressed and 23·5% (n = 66) progressed their stage from baseline to follow‐up. Baseline self‐efficacy, decisional balance and processes of change are related to follow‐up stage of changes for sexual abstinence. Participants with higher baseline self‐efficacy, lower decrease of self‐efficacy from baseline to follow‐up and lower decrease of decisional balance from baseline to follow‐up were more in the definite group (preparation and action stage) at follow‐up. Participants with higher baseline decisional balance, lower decrease of decisional balance from baseline to follow‐up and lower decrease of self‐efficacy from baseline to follow‐up were more in the advancement transition group at follow‐up.

Conclusions.  Focus of interventions could differ according to intervention purpose. Reducing the decrease of self‐efficacy and decisional balance across time is important to enable adolescents to be in or progress to better stages across time.

Relevance to clinical practice.  To make adolescents be in later stages at follow‐up, increasing baseline self‐efficacy is important. If the purpose is to progress the stages, baseline decisional balance should be emphasised. Health care providers should continually boost the self‐efficacy and decisional balance of adolescents across time.
A longitudinal study of stress and psychological distress in nurses and nursing students
Authors: Watson Roger , Gardiner Eric , Hogston Richard , Gibson Helen , Stimpson Anne , Wrate Robert , Deary Ian
Published: December 2008

Aim.  The aim of this study was to investigate how differences in life events and stress contribute to psychological distress in nurses and nursing students.

Background.  Stress is an issue for nursing students and qualified nurses leading to psychological distress and attrition.

Design.  A longitudinal study using four time waves was conducted between 1994–1997.

Methods.  Measures were taken of stress, life events and psychological distress in addition to a range of demographic data. Data were analysed using descriptive statistics, linear modelling and mixed‐effects modelling. The study was set in Scotland, UK and used newly qualified nurses and nursing students from four university departments of nursing over four years. The study was initiated with 359 participants (147 nurses and 212 nursing students) and complete data were obtained for 192 participants.

Results.  Stress levels, psychological distress and life events are all associated within time and across time. At baseline, life events and stress contributed significantly to psychological distress. The pattern of psychological distress differed between the nursing students and the newly qualified nurses with a high level in the nurses after qualifying and starting their career.

Conclusion.  Stress, individual traits, adverse life events and psychological distress are all interrelated. Future lines of enquiry should focus on the transition between being a nursing student and becoming a nurse.

Relevance to clinical practice.  Stress and psychological distress may have negative outcomes for the retention of nursing students in programmes of study and newly qualified nurses in the nursing workforce.
Audit diabetes‐dependent quality of life questionnaire: usefulness in diabetes self‐management education in the Slovak population
Authors: Holmanová Elena , Žiaková Katarína
Published: December 2008

Aim and objectives.  This paper reports a study to test validity and internal consistency of the audit diabetes‐dependent quality of life questionnaire in the Slovak population and to evaluate its usefulness in the context of education of people with diabetes.

Background.  The individualised instruments designed to measure individuals’ perceptions of the impact of diabetes on their quality of life may be helpful to identify individuals’ preferences, motivational deficits in diabetes management and to tailor individual treatment strategies.

Design.  Survey.

Methods.  After linguistic validation, the structure of the questionnaire was tested using factor analysis on 104 patients who were recruited from the National Institute of Endocrinology and Diabetology in Ľubochňa. Internal consistency was evaluated by computing Cronbach’s alpha. Clinical variables related to the quality of life were analysed using one‐way anova, multifactor anova, Pearson’s and Spearman’s rank correlation coefficients.

Results.  A one‐dimensional scale structure was supported and internal consistency was high (α = 0·93). Variance in impact of diabetes on quality of life was explained by age, presence of late complications and type of insulin regimen.

Conclusions.  The audit diabetes‐dependent quality of life is culturally appropriate, valid and reliable in the sample of Slovak patients attending the educational programme. Our results agreed with previous European and Asian studies supporting its usefulness in the context of diabetes self‐management education.

Relevance to clinical practice.  Individualised diabetes‐specific quality of life measures allow better understanding of patients’ treatment preferences and, consequently, more effective prioritising and targeting of appropriate educational interventions. This instrument may be useful in routine clinical practice and as an outcome measure for international clinical research trials evaluating effectiveness of educational programmes.
Anthropometrically derived dosing and drug costing calculations for treating visceral leishmaniasis in Bihar, India
Authors: Olliaro P. , Sundar S.
Published: December 2008

Objective and method  To estimate drug costs of treating visceral leishmaniasis (VL) based on data on the VL population structure from the high‐burden, antimony‐resistant area of Northern Bihar, India.

Results  Paromomycin is the cheapest option ($7450 to treat 1000 patients). Treating 1000 patients with oral miltefosine would cost $119 250 at the current private market price or $64 383–$75 129 at preferential public sector price depending on the size of the order. With AmBisome® it would be $163 600 or $229 500 depending on the dose (10 or 15 mg/kg total). These costs are without considering other direct costs (daily intramuscular injections for 3 weeks for paromomycin; intravenous devices and hospitalization for AmBisome®; directly observed treatment if applied for miltefosine) and indirect costs.

Conclusion  These calculations provide useful basic information for projections.
Validation of a questionnaire for assessment of asthma patient knowledge and behaviour
Authors: Trebuchon F. , Duracinsky M. , Chassany O. , Delaire C. , Eydoux E. , Longin J. , Demoly P.
Published: December 2008

Background:  For several years, educational programmes have been highlighted because care success depends on patient’s knowledge and patient’s asthma management. However, no tool is available to assess change in patient knowledge and behaviour before and after completing an educational programme.

Objective:  To validate a questionnaire measuring the knowledge and behaviour of asthmatics participating in an educational programme and to gauge the benefit of such a programme.

Methods:  The Asthma Behaviour Change (ABC) questionnaire was generated from literature, patient surveys and clinical situations. It was organized in eight dimensions assessing patient behaviour in seven different clinical situations and two assessing patient (pathophysiology and therapeutic) knowledge. A total of 139 asthmatics filled out the questionnaire before, during and after the educational programme.

Results:  The principal component analysis confirmed the structure empirically made by clinical situations. Internal consistency analysis yielded high Cronbach’s alpha values. Different dimensions and the two global scores were able to discriminate patients according to asthma severity. Finally, the effect size of difference before and after educational programme was at least 0.47, and was larger than 0.74 for both global behaviour and knowledge scores. The difference between visit 1 and 3 for global behaviour and knowledge scores reached 18.84 ± 20.83 (P < 0.001, 95% CI: 13.18–24.43) and 11.06 ± 14.98 (P < 0.001, 95% CI: 7.10–15.03), respectively.

Conclusion:  ABC questionnaire is a valid tool to assess asthmatics’ knowledge and behaviour. Furthermore, this study confirmed that educational programmes lead to better awareness of asthma by patients.