bluuebunny/crossref_metadata_2025 huggingface dataset:
The model of electric field dependent dielectric properties for porous ceramics
Authors: Zhang Yuanyuan , Wang Genshui , Wang Kefeng , Wang Yu , Dong Xianlin
Published: June 2008

The electric field dependence on the dielectric properties of the porous ceramics was studied theoretically. The dielectric constant of the porous ceramics under certain direct current (dc) bias field and the real strength electric field in the porous ceramics were given quantitatively. As the pore can share the electric field, the tunability of the porous ceramics will be decreased when the porosity increases. The dielectric constant evolution of Ba0.6Sr0.4TiO3-based porous ceramics with the dc bias electric field can be successfully explained by our theoretical results. Taking Ba0.6Sr0.4TiO3-based porous ceramic samples, for example, there is good correspondence between the theoretical and the experimental results.
Evaluation of electrode-semiconductor barrier in transparent top-contact polymer field effect transistors
Authors: Rao Manohar , Narayan K. S.
Published: June 2008

Interfacial barriers at the metal-semiconductor junction manifest in the form of sizable contact resistance in polymer field effect transistors (PFETs). We study the barrier using optical excitation directed specifically beneath the electrodes in the top-contact PFETs without optically perturbing the channel. Differences in the transconductance responses with the light localized at the source and the drain electrode region provides a considerable insight into the injection barriers.
Photo-electromotive-force from volume speckle pattern vibration with large amplitude
Authors: dos Santos T. O. , Launay J. C. , Frejlich J.
Published: June 2008

We report an accurate mathematical model describing the photo-electromotive-force signal produced by a speckle pattern of light vibrating in the volume of a photorefractive crystal with a large transverse amplitude. Our model shows that, for vibrations much faster than the material response time, the first harmonic term of the photo-electromotive-force signal exhibits a maximum at a characteristic value of the vibration-amplitude-to-speckle-size ratio that depends on the dark-to-photoconductivity ratio in the material. The theoretical results are in good agreement with experimental data from a vanadium-doped photorefractive CdTe (CdTe:V) crystal under 1064nm wavelength illumination.
Optical properties of yellow light-emitting diodes grown on semipolar (112¯2) bulk GaN substrates
Authors: Sato Hitoshi , Chung Roy B. , Hirasawa Hirohiko , Fellows Natalie , Masui Hisashi , Wu Feng , Saito Makoto , Fujito Kenji , Speck James S. , DenBaars Steven P. , Nakamura Shuji
Published: June 2008

We demonstrate high power yellow InGaN single-quantum-well light-emitting diodes (LEDs) with a peak emission wavelength of 562.7nm grown on low extended defect density semipolar (112¯2) bulk GaN substrates by metal organic chemical vapor deposition. The output power and external quantum efficiency at drive currents of 20 and 200mA under pulsed operation (10% duty cycle) were 5.9mW, 13.4% and 29.2mW, 6.4%, respectively. It was observed that the temperature dependence of the output power of InGaN LEDs was significantly smaller than that of AlInGaP LEDs.
Resistive switching of aluminum oxide for flexible memory
Authors: Kim Sungho , Choi Yang-Kyu
Published: June 2008

The unipolar resistive switching of the Al∕AlxOy∕Al structure is investigated for nonvolatile memory. Following the production of aluminum oxide film (AlxOy) by plasma oxidation, a high ratio of on-state and off-state currents (⩾104) is achieved, and characteristics of switching endurance are reported. Due to the good ductility of aluminum, the performance of resistive switching on a flexible substrate is not degraded by severe substrate bending. The low process temperature of the plasma oxidation process is advantageous for the fabrication of flexible electronic devices and modern interconnection processes.
Intrinsic optical modulation mechanism in electro-optic crystals
Authors: Garzarella A. , Hinton R. J. , Qadri S. B. , Wu Dong Ho
Published: June 2008

An intrinsic mechanism of optical intensity modulation occurring in electro-optic devices such as field sensors and modulators under applied fields is described. The optical modulation results from interactions between internally generated Fizeau interference patterns and electro-optic effects within the nonlinear crystal. Our results indicate that when phase matched with the conventional polarimetric signal, the intrinsic modulation mechanism can nearly double device sensitivity.
A carbon dioxide avoidance behavior is integrated with responses to ambient oxygen and food in
Caenorhabditis elegans
Authors: Bretscher Andrew Jonathan , Busch Karl Emanuel , de Bono Mario
Published: June 2008

Homeostasis of internal carbon dioxide (CO
2
) and oxygen (O
2
) levels is fundamental to all animals. Here we examine the CO
2
response of the nematode
Caenorhabditis elegans
. This species inhabits rotting material, which typically has a broad CO
2
concentration range. We show that well fed
C. elegans
avoid CO
2
levels above 0.5%. Animals can respond to both absolute CO
2
concentrations and changes in CO
2
levels within seconds. Responses to CO
2
do not reflect avoidance of acid pH but appear to define a new sensory response. Sensation of CO
2
is promoted by the cGMP-gated ion channel subunits TAX-2 and TAX-4, but other pathways are also important. Robust CO
2
avoidance in well fed animals requires inhibition of the DAF-16 forkhead transcription factor by the insulin-like receptor DAF-2. Starvation, which activates DAF-16, strongly suppresses CO
2
avoidance. Exposure to hypoxia (<1% O
2
) also suppresses CO
2
avoidance via activation of the hypoxia-inducible transcription factor HIF-1. The
npr-1 215V
allele of the naturally polymorphic neuropeptide receptor
npr-1
, besides inhibiting avoidance of high ambient O
2
in feeding
C. elegans
, also promotes avoidance of high CO
2
.
C. elegans
integrates competing O
2
and CO
2
sensory inputs so that one response dominates. Food and allelic variation at NPR-1 regulate which response prevails. Our results suggest that multiple sensory inputs are coordinated by
C. elegans
to generate different coherent foraging strategies.
Adaptation of Soybean mosaic virus Avirulent Chimeras Containing P3 Sequences from Virulent Strains to Rsv1-Genotype Soybeans Is Mediated by Mutations in HC-Pro
Authors: Hajimorad M. R. , Eggenberger A. L. , Hill J. H.
Published: June 2008

In Rsv1-genotype soybean, Soybean mosaic virus (SMV)-N (an avirulent isolate of strain G2) elicits extreme resistance (ER) whereas strain SMV-G7 provokes a lethal systemic hypersensitive response (LSHR). SMV-G7d, an experimentally evolved variant of SMV-G7, induces systemic mosaic. Thus, for Rsv1-genotype soybean, SMV-N is avirulent whereas SMV-G7 and SMV-G7d are both virulent. Exploiting these differential interactions, we recently mapped the elicitor functions of SMV provoking Rsv1-mediated ER and LSHR to the N-terminal 271 amino acids of P3 from SMV-N and SMV-G7, respectively. The phenotype of both SMV-G7 and SMV-G7d were rendered avirulent on Rsv1-genotype soybean when the part of the genome encoding the N-terminus or the entire P3 cistron was replaced with that from SMV-N; however, reciprocal exchanges did not confer virulence to SMV-N-derived P3 chimeras. Here, we describe virulent SMV-N-derived P3 chimeras containing the full-length or the N-terminal P3 from SMV-G7 or SMV-G7d, with or without additional mutations in P3, that were selected on Rsv1-genotype soybean by sequential transfers on rsv1 and Rsv1-genotype soybean. Sequence analyses of the P3 and helper-component proteinase (HC-Pro) cistrons of progeny recovered from Rsv1-genotype soybean consistently revealed the presence of mutations in HC-Pro. Interestingly, the precise mutations in HC-Pro required for the adaptation varied among the chimeras. No mutation was detected in the HC-Pro of progeny passaged continuously in rsv1-genotype soybean, suggesting that selection is a consequence of pressure imposed by Rsv1. Mutations in HC-Pro alone failed to confer virulence to SMV-N; however, reconstruction of mutations in HC-Pro of the SMV-N-derived P3 chimeras resulted in virulence. Taken together, the data suggest that HC-Pro complementation of P3 is essential for SMV virulence on Rsv1-genotype soybean.
Time-resolved tympanal mechanics of the locust
Authors: Windmill J.F.C , Bockenhauer S , Robert D
Published: June 2008

A salient characteristic of most auditory systems is their capacity to analyse the frequency of sound. Little is known about how such analysis is performed across the diversity of auditory systems found in animals, and especially in insects. In locusts, frequency analysis is primarily mechanical, based on vibrational waves travelling across the tympanal membrane. Different acoustic frequencies generate travelling waves that direct vibrations to distinct tympanal locations, where distinct groups of correspondingly tuned mechanosensory neurons attach. Measuring the mechanical tympanal response, for the first time, to acoustic impulses in the time domain, nanometre-range vibrational waves are characterized with high spatial and temporal resolutions. Conventional Fourier analysis is also used to characterize the response in the frequency domain. Altogether these results show that travelling waves originate from a particular tympanal location and travel across the membrane to generate oscillations in the exact region where mechanosensory neurons attach. Notably, travelling waves are unidirectional; no strong back reflection or wave resonance could be observed across the membrane. These results constitute a key step in understanding tympanal mechanics in general, and in insects in particular, but also in our knowledge of the vibrational behaviour of anisotropic media.
Seasonal polyphenism and developmental trade-offs between flight ability and egg laying in a pierid butterfly
Authors: Karlsson Bengt , Johansson Anna
Published: June 2008

Butterflies have competing demands for flight ability depending on, for example, mating system, predation pressure, the localization of host plants and dispersal needs. The flight apparatus, however, is costly to manufacture and therefore trade-offs are expected since resources are limited and must be allocated between flight ability and other functions, such as reproduction. Trade-offs between flight and reproduction may be difficult to reveal since they interact with other factors and can be confounded by differences in resource consumption. Previous studies have shown that adults of the summer generation ofPieris napihave relatively larger thoraxes compared with the spring generation. To study whether difference in thorax size results in a trade-off between flight ability and reproduction among the two generations, we conducted a split-brood experiment under common garden conditions. Our results show that summer generation adults have a higher dispersal capacity measured as flight duration in five different temperatures. Reproductive output differed between the two developmental pathways; spring generation females had a significantly higher output of eggs compared with summer generation females. We suggest that this is a consequence of a resource-allocation trade-off made during pupal development implemented by different demands for flight between the spring and summer generations. The significance of this finding is discussed in relation to reproduction and mobility in butterflies.
Genetic exchange and the origin of adaptations: prokaryotes to primates
Authors: Arnold Michael L , Sapir Yuval , Martin Noland H
Published: June 2008

Data supporting the occurrence of adaptive trait transfer (i.e. the transfer of genes and thus the phenotype of an adaptive trait through viral recombination, lateral gene transfer or introgressive hybridization) are provided in this review. Specifically, we discuss examples of lateral gene transfer and introgressive hybridization that have resulted in the transfer or de novo origin of adaptations. The evolutionary clades in which this process has been identified include all types of organisms. However, we restrict our discussion to bacteria, fungi, plants and animals. Each of these examples reflects the same consequence, namely that the transfer of genetic material, through whatever mechanism, may result in adaptive evolution. In particular, each of the events discussed has been inferred to impact adaptations to novel environmental settings in the recipient lineage.
Absorption correction based on a three-dimensional model reconstruction from visual images
Authors: Leal Ricardo M. F. , Teixeira Susana C. M. , Rey Vicente , Forsyth V. Trevor , Mitchell Edward P.
Published: June 2008

The results are presented of a feasibility study for the application of absorption corrections to macromolecular crystallographic X-ray diffraction data using a three-dimensional crystal model generated photographically. The model allows path lengths through the crystal, the solvent and the crystal mount system to be determined. The approach has been tested on the macromolecular crystallography beamline ID23-1 at the ESRF in Grenoble using a model insulin system with the standard mini diffractometer facilities, which incorporate high-quality camera systems for sample alignment. Data from the insulin crystal at low incident beam energy (6.0 keV or 2.1 Å) were recorded and processed using this approach. The resulting data are compared against those treated using an empirical method and show significant improvement. The methods described here are of general interest, particularly for long-wavelength X-ray work, and may also be applied to account for absorption effects in neutron crystallography.
MicroRNA signatures characterize diffuse large B‐cell lymphomas and follicular lymphomas
Authors: Roehle Anja , Hoefig Kai P. , Repsilber Dirk , Thorns Christoph , Ziepert Marita , Wesche Kai O. , Thiere Marlen , Loeffler Markus , Klapper Wolfram , Pfreundschuh Michael , Matolcsy András , Bernd Heinz‐Wolfram , Reiniger Lila , Merz Hartmut , Feller Alfred C.
Published: June 2008

MicroRNAs (miRNA, miR) are negative regulators of gene expression that play an important role in diverse biological processes such as development, cell growth, apoptosis and haematopoiesis, suggesting their association with cancer. Here we analysed the expression signatures of 157 miRNAs in 58 diffuse large B‐cell lymphoma (DLBCL), 46 follicular lymphoma (FL) and seven non‐neoplastic lymph nodes (LN). Comparison of the possible combinations of DLBCL‐, FL‐ and LN resulted in specific DLBCL‐ and FL‐signatures, which include miRNAs with previously published function in haematopoiesis (MIRN150 and MIRN155) or tumour development (MIRN210, MIRN10A, MIRN17‐5P and MIRN145). As compared to LN, some miRNAs are differentially regulated in both lymphoma types (MIRN155, MIRN210, MIRN106A, MIRN149 and MIRN139). Conversely, some miRNAs show lymphoma‐specific aberrant expression, such as MIRN9/9*, MIRN301, MIRN338 and MIRN213 in FL and MIRN150, MIRN17‐5P, MIRN145, MIRN328 and others in DLBCL. A classification tree was computed using four miRNAs (MIRN330, MIRN17‐5P, MIRN106a and MIRN210) to correctly identify 98% of all 111 cases that were analysed in this study. Finally, eight miRNAs were found to correlate with event‐free and overall survival in DLBCL including known tumour suppressors (MIRN21, MIRN127 and MIRN34a) and oncogenes (MIRN195 and MIRNLET7G).
Goal Attainment Scaling in paediatric rehabilitation: a report on the clinical training of an interdisciplinary team
Authors: Steenbeek D. , Ketelaar M. , Galama K. , Gorter J. W.
Published: June 2008

Background  Goal Attainment Scaling (GAS) is a responsive method for individual goal setting and treatment evaluation. However, current knowledge about its reliability when used in paediatric rehabilitation treatment is insufficient and depends highly on standardization of the GAS method. A training programme was developed to introduce GAS to a team of 27 professionals from five disciplines. The purpose of the paper is to share the experiences of professionals and parents during this training.

Methods  The training consisted of three 2‐h general discussion sessions and intensive individual feedback from the study leader (i.e. the first author). Feedback was given until the GAS scales met predetermined criteria of ordinality, described specific, measurable, acceptable, realistic abilities and activities in a single dimension, used the ‘can‐do’ principle and could be scored within 10 min. Therapists and parents were asked to give their opinion by completing a questionnaire.

Results  One hundred and fifteen GAS scales were developed and scored by professionals. The development of a GAS scale remained a time‐consuming procedure, despite the training: 45 (SD = 27) minutes per scale. The content criteria of GAS were found to be useful by all participants. Common issues requiring revision of the initial scales were equal scale intervals, specificity, measurability and selection of a single variable. After the training, 70% of the therapists and 60% of the parents regarded GAS as a suitable tool to improve the quality of rehabilitation treatment. Examples of GAS scales developed by the various disciplines are presented and discussed.

Conclusions  The experiences reported in this paper support the further development of training procedures for GAS before it can be used as an outcome measure in effect studies. The findings may be helpful in introducing GAS in the field of childhood disability.
Relationships among coping, comorbidity and stress in patients having haemodialysis
Authors: Yeh Shu‐Chuan Jennifer , Huang Chia‐Hsiung , Chou Hsueh‐Chih
Published: June 2008

Title.  Relationships among coping, comorbidity and stress in patients having haemodialysis.

Aim.  This paper is a report of a study to examine relationships among stress, coping and comorbidity and test the interaction effect of comorbidity.

Background.  Haemodialysis imposes a variety of physical and psychosocial stressors that challenge patients. Comorbidity is a risk factor for many health outcomes. Research on how comorbidity influences the relationship between coping and stress is limited.

Method.  In this cross‐sectional study, conducted from October 2002 to January 2003, 2642 patients, who had been having haemodialysis for at least 3 months, were interviewed by nursing managers in the 27 participating centres. The Haemodialysis Stressor Scale measured stressors and the Jalowiec Coping Scale were used to measure coping strategies. Hierarchical regression was used to analyse the data.

Results.  Haemodialysis patients with comorbidities were found to have higher levels of stress. Comorbidity had a moderating effect between choice of problem‐oriented responses and isolated thoughts as coping strategies. These findings show that haemodialysis patients with comorbidities often choose positive coping strategies.

Conclusion.  Comorbidity not only has a direct impact on stress but also has a moderating effect on the relationship between coping and stress. Comorbidity may hold the key to healthcare professionals’ understanding of why patients having haemodialysis perceive different levels of stress and use various coping strategies. A personalized programme may be needed for each patient based on their different levels of comorbidity.
Gap‐phase dynamics and coexistence of a long‐lived pioneer and shade‐tolerant tree species in the canopy of an old‐growth coastal temperate rain forest of Chiloé Island, Chile
Authors: Gutiérrez Alvaro G. , Aravena Juan Carlos , Carrasco‐Farías Natalia V. , Christie Duncan A. , Fuentes Mauricio , Armesto Juan J.
Published: June 2008

Aim  A major question with regard to the ecology of temperate rain forests in south‐central Chile is how pioneer and shade‐tolerant tree species coexist in old‐growth forests. We explored the correspondence between tree regeneration dynamics and life‐history traits to explain the coexistence of these two functional types in stands apparently representing a non‐equilibrium mixture.

Location  This study was conducted in northern Chiloé Island, Chile (41.6° S, 73.9° W) in a temperate coastal rain forest with no evidence of stand disruption by human impact.

Methods  We assessed stand structure by sampling all stems within two 50 × 20 m and four 5 × 100 m plots. A 600‐m long transect, with 20 uniformly spaced sampling points, was used to quantify seedling and sapling densities, obtain increment cores, and randomly select 10 tree‐fall gaps. We used tree‐ring analysis to assess establishment periods and to relate the influences of disturbances to the regeneration dynamics of the main canopy species.

Results  Canopy emergent tree species were the long‐lived pioneer Eucryphia cordifolia and the shade‐tolerant Aextoxicon punctatum. Shade‐tolerant species such as Laureliopsis philippiana and several species of Myrtaceae occupied the main canopy. The stem diameter distribution for E. cordifolia was distinctly unimodal, while for A. punctatum it was multi‐modal, with all age classes represented. Myrtaceae accounted for most of the small trees. Most tree seedlings and saplings occurred beneath canopy gaps. Based on tree‐ring counts, the largest individuals of A. punctatum and E. cordifolia had minimum ages estimated to be > 350 years and > 286 years, respectively. Shade‐tolerant Myrtaceae species and L. philippiana had shorter life spans (< 200 years). Most growth releases, regardless of tree species, were moderate and have occurred continuously since 1750.

Main conclusions  We suggest that this coastal forest has remained largely free of stand‐disrupting disturbances for at least 450 years, without substantial changes in canopy composition. Release patterns are consistent with this hypothesis and suggest that the disturbance regime is dominated by individual tree‐fall gaps, with sporadic multiple tree falls. Long life spans, maximum height and differences in shade tolerance provide a basis for understanding the long‐term coexistence of pioneer and shade‐tolerant tree species in this coastal, old‐growth rain forest, despite the rarity of major disturbances.
The effect of age and gender on arterial stiffness in healthy Caucasian Canadians
Authors: Noon Joseph P , Trischuk Timothy C , Gaucher Sylvia A , Galante Sean , Scott Roger L
Published: June 2008

Aims and objectives.  We aimed to investigate age and gender differences in arterial stiffness, and whether this cardiovascular risk factor was detectable in healthy Caucasians before established disease was manifest.

Background.  A growing number of risk factors including diabetes, obesity, hypertension, hyperlipidaemia, smoking and age have been linked to the adverse cardiovascular end‐points of myocardial infarction, stroke and heart failure. These risk factors lead to an increase in arterial stiffness. Measuring this stiffness at an early age may identify candidates for primary preventative intervention strategies by nurses.

Methods.  Caucasian Canadians (n = 176) were recruited. Peripheral and central blood pressure, pulse pressure, augmentation pressure, arterial compliance (augmentation index and pulse wave velocity) and sub‐endocardial viability ratio (SEVR), were assessed using applanation tonometry (SphygmoCor® system). Blood was drawn for fasting lipid and glucose profiling.

Results.  Women participants had significantly stiffer arteries than men (augmentation index: 28 SEM = 1% vs. 18 SEM = 2% respectively; p < 0·001). Pulse wave velocity, however, was not different (7·7 SEM = 0·2 m/s vs. 8·3 SEM = 0·1 m/s respectively; p < 0·001). Age was a strong predictor of arterial stiffening in both genders, but the effect was greater in women.

Conclusions.  Women having stiffer arteries than men, thus at greater cardiovascular risk, may require earlier screening. The effect might be postmenopausal, and mechanisms require further investigation. However, both middle‐aged men and women considering themselves ‘healthy’ may benefit from more proactive primary prevention.

Relevance to clinical practice.  Applanation tonometry, used extensively by nurses, provides early detection of central haemodynamic changes and vascular compliance at all ages. Knowledge of arterial stiffness could guide the management of primary prevention in the nursing cardiovascular risk reduction clinic.
Drug contamination of the equine racetrack environment: a preliminary examination
Authors: BARKER S. A.
Published: June 2008

Advances in analytical technology now make it feasible to detect and confirm exceptionally low concentrations (pg to fg/mL) of drugs and their metabolites in equine biological fluids. These new capabilities complicate the regulatory interpretation of drug positives and bring into question the fair application of medication rules. Such approaches and policies are further complicated by the possibility that drug positives may arise from contamination of the equine environment on the backstretch of the race track. This manuscript provides data demonstrating that the general environment of the backstretch in which horses live is contaminated with therapeutic drugs and drugs of human origin. The major contaminants are nonsteroidal anti‐inflammatory drugs, such as flunixin, phenylbutazone and naproxen, present in the soil in stalls, on stall surfaces, in the dust that circulates and in the lagoon waters that accumulate on the backstretch. The presence of caffeine and cotinine suggest other possible vectors for contamination by humans. Concentrations of these compounds as well as their frequency of occurrence are provided.
Pharmacokinetics of eight anticoagulant rodenticides in mice after single oral administration
Authors: VANDENBROUCKE V. , BOUSQUET‐MELOU A. , De BACKER P. , CROUBELS S.
Published: June 2008

The first aim of the study was to investigate the pharmacokinetics of eight anticoagulant rodenticides (brodifacoum, bromadiolone, chlorophacinone, coumatetralyl, difenacoum, difethialone, flocoumafen and warfarin) in plasma and liver of the mouse after single oral administration. Eight groups of mice dosed orally with a different anticoagulant rodenticide in a dose equal to one‐half the lethal dose 50 (LD50), were killed at various times up to 21 days after administration. The eight anticoagulant rodenticides were assayed in plasma and liver by an LC‐ESI‐MS/MS method. Depending on the compound, the limit of quantification was set at 1 or 5 ng/mL in plasma. In liver, the limit of quantification was set at 250 ng/g for coumatetralyl and warfarin and at 100 ng/g for the other compounds. The elimination half‐lives in plasma for first‐generation rodenticides were shorter than those for second‐generation rodenticides. Coumatetralyl, a first‐generation product, had a plasma elimination half‐life of 0.52 days. Brodifacoum, a second‐generation product, showed a plasma elimination half‐life of 91.7 days. The elimination half‐lives in liver varied from 15.8 days for coumatetralyl to 307.4 days for brodifacoum. The second aim of the study was to illustrate the applicability of the developed method in a clinical case of a dog suspected of rodenticide poisoning.
Impact of liver transplantation on rate‐corrected QT interval and myocardial function in children with chronic liver disease*
Authors: Arikan Cigdem , Kilic Murat , Tumgor Gokhan , Levent Erturk , Yuksekkaya Hasan A. , Yagci Rasit V. , Aydogdu Sema
Published: June 2008

Abstract:  Prolonged QTc interval (>440 ms) is a common abnormality in adult patients with CLD and has been reported to predict patient survival. In this study, 88 children who underwent evaluation for LT, including a 12‐lead electrocardiogram and echocardiogram included to determine the frequency of QTc prolongation and related factors in children with CLD and the effect of LT on these factors. Sixty‐nine healthy, age‐ and sex‐matched children served as controls. QTc interval was prolonged in 40 CLD patients (45.4%). It was found to be related to PELD score and presence of portal hypertension. Mean QTc was higher in patients who died prior to LT than in the survivors without LT. Mortality risk was increased 3.66‐fold in patients with prolonged QTc (p = 0.001, 95% CI: 2–7.2). Cox regression analysis showed that only PELD score was an independent predictor of survival (p = 0.001, β = −0.41, 95% CI: 5.58–1.82). Five of 48 transplanted children died within three months post‐transplant; QTc was not related to post‐transplant survival (p = 0.27). QTc normalized in 63.8% patients after LT. After LT, LAD, LVEF, and LVPWT decreased. In conclusion, QTc prolongation is common in children with CLD and associated with high mortality. It may be useful for assessment of the severity of CLD and for the timing for transplantation.
Investigation of Developmental Toxicity and Teratogenicity of Macrolide Antibiotics in Cultured Rat Embryos
Authors: Karabulut A. K. , Uysal I. I. , Acar H. , Fazliogullari Z.
Published: June 2008

Macrolides are considered to be one of the safest anti‐infective groups in clinical use, with severe adverse reactions being rare. However, there are limited data about their embryotoxicity and teratogenicity. We aimed to investigate and compare the effects of these agents on embryonic growth and development. Rat embryos were cultured in vitro for 48 h in rat serum. Whole rat serum was used as a culture medium for the control group while different concentrations of spiramycin and azithromycin (1.25–6.25 μg/ml), and clarithromycin (2.5–30 μg/ml) were added to rat serum for the experimental groups. Dose‐dependent effects of macrolides on embryonic developmental parameters were compared using morphological methods. Embryos were evaluated for the presence of any malformations. After morphological examination of the embryos, total DNA was extracted from the cells using standard procedures to determine fragmentation of nuclear DNA of embryonic cells. When compared with the control embryos, the macrolides significantly decreased all growth and developmental parameters dose dependently. While clarithromycin was found to cause more developmental toxicity than spiramycin and azithromycin, azitromycin was determined to have more teratogenicity potential. Compared with controls, there was no difference regarding the fragmentation of nuclear DNA of all the agents used. According to these results, when the toxic and teratogenic potential of the used agents compared, because of the lower toxic and teratogenic effects observed with spiramycin, this agent may be preferred for parturients.
Isolation of a Novel Tomato Caffeoyl CoA 3‐O‐methyltransferase Gene Following Infection with the Bacterium Ralstonia solanacearum
Authors: Miao L. , Shou S. , Zhu Z. , Jiang F. , Zai W. , Yang Y.
Published: June 2008

We combined cDNA amplified fragment length polymorphism (cDNA‐AFLP) with bulked segregant analysis (BSA) to detect genes that control tomato (Lycopersicon esculentum) bacterial wilt infected with Ralstonia solanacearum, resistance in F2 population derived from a cross between a bacterial wilt‐resistant variety, T51A, and a bacterial wilt‐susceptible variety, T9230. In cDNA‐AFLP analysis among bulked‐resistant F2 (BR) pool, bulked‐susceptible F2 (BS) pool, bulked‐resistant T51A (BA) pool and bulked‐susceptible T9230 (BB) pool, 34 differentially expressed transcript‐derived fragments (DE‐TDFs) that were present in only BR and BA pools were detected. Analysis of differential DE‐TDF expression in individual resistant F2 resulted in the isolation of a caffeoyl CoA 3‐O‐methyltransferase (CCoAOMT) gene not previously described from tomato and which showed similarity to an CCoAOMT gene from tobacco and potato plants. This CCoAOMT gene may play a role in innate generalized response to pathogen infection as it was downregulated in susceptible tomato following infection with the bacterium. CCoAOMT gene plays an essential role in the synthesis of guaiacyl lignin units and supply substrates for the synthesis of syringyl lignin units.
Partial Uprooting and Pulling to Induce Recovery in Bois noir‐Infected Grapevines
Authors: Romanazzi Gianfranco , Murolo Sergio
Published: June 2008

Grapevine yellows (GY) are diseases caused by phytoplasmas, which are able to induce severe loss of production and death of plants. Bois noir (BN) and Flavescence dorée are the most important GY diseases prevalent in several European countries. As of now, there are no known effective disease‐control methods for application in grapevines infected by these phytoplasmas. In these plants, it is possible to have, remission of these symptoms, better known as ‘recovery’. In April 2006 in the Marche region, central‐eastern Italy, grapevines cv. Chardonnay, Verdicchio and Sangiovese grafted onto Kober 5BB; rootstock symptomatically infected by VK type II BN were subjected to partial uprooting, which was effected by breaking most of their roots using a small excavator. Almost all of these plants failed to show disease symptoms in the autumn of 2006 and 2007. Similar trials were carried out on BN‐infected plants cv. Chardonnay grafted onto 420A rootstock in 2006 and 2007; in this case, the treatment was only partially successful in both these years. In another trial in April 2007, BN‐infected plants cv. Chardonnay grafted onto 420A rootstock and cv. Primitivo grafted onto Kober 5BB, rootstock were ‘pulled’ and some of these showed no disease symptoms in the following autumn, whereas others had only mild infections. Partial uprooting and pulling are agronomical practices that induce stress in the plants. In the case of grapevines affected by GY, such stress can result in the recovery of the vines. However, the effectiveness in the induction of recovery in these treatments can depend on the rootstock.
Seasonal Variation of Reproductive Performance, Foetal Development and Progesterone Concentrations of Sheep in the Subtropics
Authors: Ali A , Hayder M
Published: June 2008

Contents

The aim of the present study was to investigate the effect of breeding season [late spring (LSP) vs winter (WIN)] on reproductive performances, foetal development and progesterone (P4) concentrations of sheep in the subtropics. Ewes of Farafra breed were exposed for mating in LSP (n = 79) and WIN (n = 45). Ultrasonographic examinations were performed at days 25, 45 and 75 of mating to estimate the pregnancy rate, incidence of twinning and percentage of foetal losses. Foetal growth rate was determined at 10‐day interval, and blood samples were taken on days 0 (oestrus), 8, 18 of oestrous cycle and on days 30, 45, 60 and 90 of pregnancy for P4 analysis. The results showed that pregnancy and lambing rates were greater (p < 0.01) for ewes mated in LSP (93.7% and 92.4%) than for those mated in WIN (75.6% and 71.1%), respectively. There was no effect of season on the incidence of twinning (overall 19.1%) or the frequency of foetal losses (overall 7.3%). Transient reduction of placental size, foetal growth and P4 concentration was observed following LSP matings. In conclusion, pregnancy and lambing rates were higher following LSP matings. Summer heat stress of the late spring mated ewes transiently interferes with foetal growth and P4 concentrations.
Heterozygous reeler mice exhibit alterations in sensorimotor gating but not presynaptic proteins
Authors: Barr Alasdair M. , Fish Kenneth N. , Markou Athina , Honer William G.
Published: June 2008

Post mortem, reduced brain reelin is noted in schizophrenia. Accordingly, the reelin‐haploinsufficient heterozygous reeler mouse (HRM) has been posited as a murine model of the illness. One study reported that HRM exhibit deficits in prepulse inhibition (PPI) of the acoustic startle reflex, a sensorimotor‐gating behavior that is disrupted in schizophrenia, although this finding has not been reproduced. To extend the characterization of putative sensorimotor‐gating deficits in HRM, these mice were subjected to a sophisticated series of PPI tests. Mice were tested in a cross‐modal PPI protocol that combined an acoustic prepulse with a tactile startle stimulus and also in a protocol that included varying prepulse–pulse intervals and varying acoustic startle pulse intensities. Levels of acoustic startle habituation and cross‐modal PPI were significantly lower in HRM, although unimodal PPI did not differ. The HRM also exhibited increased PPI compared to wildtypes at short interstimulus intervals between prepulse and pulse stimuli when the interval between the acoustic prepulse and pulse were varied, and were more reactive to higher intensity startle stimuli. Some of these deficits in sensorimotor gating parallel those of schizophrenia, a disease characterized by alterations in synaptic protein expression. Therefore, levels of presynaptic proteins were measured in multiple brain regions using ELISA in HRM. No significant alterations in presynaptic protein expression were found. Thus, HRM exhibit a complex pattern of changes in startle reactivity and sensorimotor gating, with both similarities to and differences from schizophrenia. However, it is unlikely that these behavioral differences may be accounted for by altered regional levels of presynaptic proteins.
Vascular changes in the cerebellum of Norrin /Ndph knockout mice correlate with high expression of Norrin and Frizzled‐4
Authors: Luhmann Ulrich F. O. , Neidhardt John , Kloeckener‐Gruissem Barbara , Schäfer Nikolaus F. , Glaus Esther , Feil Silke , Berger Wolfgang
Published: June 2008

X‐linked Norrie disease, familial exudative vitreoretinopathy (FEVR), Coat’s disease and retinopathy of prematurity are severe human eye diseases and can all be caused by mutations in the Norrie disease pseudoglioma gene. They all show vascular defects and characteristic features of retinal hypoxia. Only Norrie disease displays additional neurological symptoms, which are sensorineural hearing loss and mental retardation. In the present study, we analysed transcript levels of the ligand Norrin (Ndph) and its two receptors Frizzled‐4 (Fzd4) and LDL‐related protein receptor 5 (Lrp5) in six different brain regions (cerebellum, cortex, hippocampus, olfactory bulb, pituitary and brain stem) of 6‐ to 8‐month‐old wild‐type and Ndph knockout mice by quantitative real‐time PCR. No effect of the Ndph knockout allele on Fzd4 or Lrp5 receptor expression was found. Furthermore, no alterations of the transcript levels of three hypoxia‐regulated angiogenic factors (Vegfa, Itgrb3 and Tie1) were observed in the absence of Norrin. Interestingly, we identified significant differences in Ndph, Fzd4 and Lrp5 transcript levels in brain regions of wild‐type mice and observed highest expression of Norrin and frizzled‐4 in cerebellum. Transcript analyses were correlated with morphological data obtained from cerebellum and immunohistochemical studies of blood vessels in different brain regions. Vessel density was reduced in the cerebellum of Ndph knockout mice but the number of Purkinje and granular cells was not altered. This provides the first description of a brain phenotype in Ndph knockout mice, which will help to elucidate the role of Norrin in the brain.
Decreased olfactory mucus secretion and nasal abnormality in mice lacking type 2 and type 3 IP3 receptors
Authors: Fukuda Nanaho , Shirasu Mika , Sato Koji , Ebisui Etsuko , Touhara Kazushige , Mikoshiba Katsuhiko
Published: June 2008

Although nasal mucus is thought to play important roles in the mammalian olfactory system, the mechanisms of secretion of it and its physiological roles are poorly understood. Here we show that type 2 and type 3 IP3 receptors (IP3R2 and IP3R3) play critical roles in olfactory mucus secretion. Histological studies showed that IP3R2 and IP3R3 are predominantly expressed in two types of nasal glands, the anterior glands of the nasal septum and the lateral nasal glands (LNG), which contain mucosal proteins secreted to the main olfactory epithelium. We therefore examined LNG acinar cells, and found that acetylcholine‐mediated calcium responses and fluid‐ and protein‐ secretion in the acinar cells were markedly decreased in IP3R2–R3 double‐knockout (KO) mice. We also found nasal inflammation and a decrease in olfactory capacity in IP3R2–R3 KO mice. Despite intact signal transduction in the olfactory epithelium, IP3R2–R3 KO mice exhibited elevated threshold sensitivity to odorants on in vivo imaging of olfactory glomerular responses and behavioral tests. Our findings suggest that IP3R2 and IP3R3 mediate nasal mucus secretion, which is important for the maintenance of nasal tissue as well as the perception of odors.
Selective visual responses to expansion and rotation in the human MT complex revealed by functional magnetic resonance imaging adaptation
Authors: Wall Matthew B. , Lingnau Angelika , Ashida Hiroshi , Smith Andrew T.
Published: June 2008

Many neurons in the macaque visual area MSTd are sensitive to the global structure of a pattern of moving dots, responding to optic flow components such as expansion and rotation. Direct evidence for neurons with similar properties in humans has been lacking. We have explored sensitivity to optic flow in the human occipital cortex using an event‐related functional magnetic resonance imaging adaptation paradigm. On each trial, two brief random‐dot kinematograms were presented sequentially. Attention was controlled with a demanding task at fixation. In human MST, the compound response was smaller (indicating adaptation) when the two had the same flow structure than when they were different, suggesting the presence of separate neural populations sensitive to rotation and expansion. Surprisingly, the middle‐temporal (MT) gyrus visual area also showed signs of flow specificity, and even V3A showed weak specificity. In V1, which is expected to respond only to local dot motions, no evidence of flow‐specific neurons was found. The same was true in V2, V3, V3B and V4. Control experiments showed that the results cannot be attributed to adaptation to local translation within the flow pattern, or to attentional effects. Our results clearly demonstrate selective responses to specific optic flow structures in MST, and we tentatively suggest that the human MT and even V3A may show similar properties.
Leptin—a predictor of abnormal glucose tolerance and prognosis in patients with myocardial infarction and without previously known Type 2 diabetes
Authors: Wallander M. , Söderberg S. , Norhammar A.
Published: June 2008

Aims  High levels of leptin and low adiponectin are associated with Type 2 diabetes mellitus (T2DM) and cardiovascular (CV) disease. We studied the prognostic implications of leptin and adiponectin in patients with acute myocardial infarction (AMI) without previously known Type 2 DM.

Methods  One hundred and eighty‐one patients were included. Based on an oral glucose tolerance test at hospital discharge (day 4–5), 168 (67% men) had normal or abnormal glucose tolerance (AGT), defined as impaired glucose tolerance or T2DM. Sex‐ and age‐matched healthy persons served as control subjects (n = 185). The associations between fasting serum leptin and adiponectin (day 2) and newly discovered AGT and CV events (CV mortality, non‐fatal stroke, reinfarction or severe heart failure) during a median follow‐up of 34 months were investigated.

Results  Compared with control subjects, patients of both genders had significantly higher levels of leptin 2 days after an AMI. These levels were higher than those obtained at hospital discharge and 3 months later. Circulating levels of (ln) leptin 2 days after the AMI predicted AGT at discharge (odds ratio 2.03, P = 0.042). Ln leptin at day 2 was the only biochemical variable that significantly predicted CV events both on univariate [hazard ratio (HR) 1.60, P = 0.018] and on multivariate analysis (HR 1.75, P = 0.045). Adiponectin levels did not differ between patients and control subjects and did not relate to AGT or CV events.

Conclusions  Elevated circulating levels of leptin on the first morning after an AMI are associated with the presence of AGT at discharge and with a poorer long‐term prognosis.
Alterations in renal cilium length during transient complete ureteral obstruction in the mouse
Authors: Wang Leanne , Weidenfeld Raphael , Verghese Elizabeth , Ricardo Sharon D. , Deane James A.
Published: June 2008

The renal cilium is a non‐motile sensory organelle that has been implicated in the control of epithelial phenotype in the kidney. The contribution of renal cilium defects to cystic kidney disease has been the subject of intense study. However, very little is known of the behaviour of this organelle during renal injury and repair. Here we investigate the distribution and dimensions of renal cilia in a mouse model of unilateral ureteral obstruction and reversal of ureteral obstruction. An approximate doubling in the length of renal cilia was observed throughout the nephron and collecting duct of the kidney after 10 days of unilateral ureteral obstruction. A normalization of cilium length was observed during the resolution of renal injury that occurs following the release of ureteral obstruction. Thus variations in the length of the renal cilium appear to be a previously unappreciated indicator of the status of renal injury and repair. Furthermore, increased cilium length following renal injury has implications for the specification of epithelial phenotype during repair of the renal tubule and duct.
Nutrient availability moderates transpiration in Ehrharta calycina
Authors: Cramer Michael D. , Hoffmann Vera , Verboom G. Anthony
Published: June 2008

DOI: 10.1111/j.1469-8137.2008.02595.xCommentary p 905
Effects of Opioid Receptor Gene Variation on Targeted Nalmefene Treatment in Heavy Drinkers
Authors: Arias Albert J. , Armeli Stephen , Gelernter Joel , Covault Jonathan , Kallio Antero , Karhuvaara Sakari , Koivisto Tiina , Mäkelä Rauno , Kranzler Henry R.
Published: June 2008

Background:  Recent studies examining the moderating effects of polymorphic variation in opioid receptor genes have yielded conflicting results. We examined opioid receptor gene polymorphisms as moderators of the therapeutic effects of the opioid antagonist nalmefene.

Methods:  Participants (n = 272) were subjects who consented to the pharmacogenetic analysis of a multi‐site, randomized, placebo‐controlled trial of targeted nalmefene for the reduction of heavy drinking. We genotyped two single nucleotide polymorphisms (SNPs) in OPRM1 (including A118G, a commonly studied SNP that encodes an Asn40Asp amino acid substitution), two SNPs in OPRD1, and one SNP in OPRK1, which encode the μ‐, δ‐, and κ‐opioid receptors, respectively. Regression analysis served to examine the moderating effects of these SNPs on medication response.

Results:  As previously described by Karhuvaara et al. (2007), nalmefene significantly reduced the number of heavy drinking and very heavy drinking days per week, compared with placebo. There were no main or moderating effects of the genotypes examined on these outcomes.

Conclusions:  Our finding that the therapeutic effects of targeted nalmefene were not moderated by polymorphic variation in opioid receptor genes is consistent with two recent reports showing that variation in opioid receptor genes does not moderate the response to naltrexone. However, these findings contrast with those from two other studies, in which the Asn40Asp polymorphism in OPRM1 moderated the naltrexone treatment response. Additional research is needed to clarify the role of variation in opioid receptor genes on the response to opioid antagonist treatment of alcoholism.
Case–Cohort Analysis with Accelerated Failure Time Model
Authors: Kong Lan , Cai Jianwen
Published: June 2008

Summary In a case–cohort design, covariates are assembled only for a subcohort that is randomly selected from the entire cohort and any additional cases outside the subcohort. This design is appealing for large cohort studies of rare disease, especially when the exposures of interest are expensive to ascertain for all the subjects. We propose statistical methods for analyzing the case–cohort data with a semiparametric accelerated failure time model that interprets the covariates effects as to accelerate or decelerate the time to failure. Asymptotic properties of the proposed estimators are developed. The finite sample properties of case–cohort estimator and its relative efficiency to full cohort estimator are assessed via simulation studies. A real example from a study of cardiovascular disease is provided to illustrate the estimating procedure.