bluuebunny/crossref_metadata_2025 huggingface dataset:
Data Envelopment Analysis to Evaluate the Reliance and Engagement of Florida Communities on Gulf of Mexico Commercial Red Snapper Fisheries
Authors: Alsharif Kamal A , Miller Nathan
Published: January 2012

The red snapper fishery is impacted by the individual fishing quotas (IFQ) program, which is considered a new paradigm for the red snapper fishery in the Gulf of Mexico. The commercial red snapper fishery is one of the essential fishing industries in Florida, and its management is crucial to maintain healthy, sustainable communities. To determine the involvement of Florida Gulf Coast communities in the commercial red snapper fishery and thus the potential extent of fishery-related decisions, this study made use of data envelopment analysis (DEA), an estimation performance technique. Some of the most interesting findings of this study show that larger communities tended to be more engaged in the fishery than they were reliant on it, whereas smaller communities with populations of 5,000 people or fewer tended to exhibit more reliance on the fishery than larger or even mid-sized communities.

RESUMEN

La pesquería de huachinango es impactada por el programa de Cuotas Individuales de Pesca (CIP), el cual se considera como el nuevo paradigma para esta pesquería en el Golfo de México. La pesquería del huachinango es esencial en las industrias pesqueras de Florida, y su manejo es crucial en el mantenimiento de la salud y sustentabilidad de las comunidades. Para determinar el grado de involucramiento de las comunidades costeras de Florida en la pesquería comercial de huachinango y, por consiguiente, el alcance potencial de las decisiones relativas a la pesquería, en este estudio se utilizó el Análisis de Inclusión de Datos (AIC); técnica empleada para estimar desempeño. Algunos de los hallazgos más interesantes de este trabajo mostraron que comunidades numerosas tienden a comprometerse con la pesquería más que a confiar en ella, mientras que las comunidades más pequeñas, compuestas por 5,000 personas o menos, tendieron a exhibir más confianza en la pesquería en comparación con las comunidades medianas o grandes
TIPS-DBC small molecule O-FETs fabricated by evaporation and solution processing
Authors: Gruszecki Daniel , Singh Birendra , Bown Mark , Lewis David
Published: January 2012

The performance of organic field effect transistors using the small molecule, tri-isopropyl- silane-di-benzo chrysene (TIPS-DBC) is reported. The field effect mobility μFE is found to depend on the deposition conditions, which affect the morphology of the film. A mobility in the range of 1.5 × 10−6 to 2.4 × 10−4 cm2 V−1 s−1 is obtained from the evaporated films depending on the substrate treatment and deposition temperature, while films deposited by solution-processing techniques yield mobilities in the range of 0.7 × 10−3 to 1.5 × 10−3 cm2 V−1 s−1. The enhanced performance in polycrystalline solution-processed coatings and its relationship to crystallite size is an important parameter in the design of high-performance devices based on small molecules.
Bimodal gate-dielectric deposition for improved performance of AlGaN/GaN metal–oxide–semiconductor high-electron-mobility transistors
Authors: Pang Liang , Kim Kyekyoon (Kevin)
Published: January 2012

A bimodal deposition scheme combining radiofrequency magnetron sputtering and plasma enhanced chemical vapour deposition (PECVD) is proposed as a means for improving the performance of GaN-based metal–oxide–semiconductor high-electron-mobility transistors (MOSHEMTs). High-density sputtered-SiO2 is utilized to reduce the gate leakage current and enhance the breakdown voltage while low-density PECVD-SiO2 is employed to buffer the sputtering damage and further increase the drain current by engineering the stress-induced-polarization. Thus-fabricated MOSHEMT exhibited a low leakage current of 4.21 × 10−9 A mm−1 and high breakdown voltage of 634 V for a gate–drain distance of 6 µm, demonstrating the promise of bimodal-SiO2 deposition scheme for the development of GaN-based MOSHEMTs for high-power application.
Point-to-plane pulsed discharge initiated flame structure modification in propane–air flame
Authors: Schmidt Jacob B , Ganguly Biswa N
Published: January 2012

The effect of a point-to-plane pulsed discharge on a propane/air flame has been investigated by phase-locked simultaneous measurements of the change in gas temperature and OH planar laser-induced-fluorescence (PLIF). Phase-locked simultaneous measurement of gas temperature through spontaneous Raman scattering and OH PLIF with the variation of pulsed plasma energy and plasma generation location with respect to the flame holder and flame reaction zone have been performed. A fast rise time (15 ns) and a slower rise time (150 ns) high voltage pulsers are used to produce OH radical densities 50% greater than the ambient flame produced OH radicals in both lean and rich premixed flames. The excess OH radical densities were found to decay to the 50% level with time constants greater than 100 µs in the burnt gas regions with gas temperatures greater than 1000 K. The flame perturbation was dependent on the pulse repetition rates as well as on the pulse rise time for similar energy deposition per pulse. A laser photo-deflection measurement of acoustic pressure pulse generation by the pulsed discharge suggests that flame perturbation by the downstream plasma is caused mostly by flow perturbation.
Effect of surface treatment on hot-filament chemical vapour deposition grown diamond films
Authors: Ali M , Ürgen M , Atta M A
Published: January 2012

Diamond film growth without seeding treatment has been the subject of numerous studies. In this study, diamond films with/without seeding treatment were grown on silicon using hot-filament chemical vapour deposition. An inexpensive and simple approach, namely ‘dry ultrasonic treatment’, was introduced in which full coverage of the diamond film was achieved over the substrate having no prior seeding treatment. For comparison purposes, two substrates were seeded with different sizes of diamond particles, 5 µm by hand and 30–40 µm by ultrasonic agitation, prior to deposition. The produced diamond films were examined through standard characterization tools and distinct features were observed in each film. The diamond film grown without the seeding treatment shows slightly lower growth rate (1 µm h−1) but bigger grain size up to 8 µm compared with seeded films. Here we show the growth of uniform and high-purity diamond films free from nano-sized grains, which are grown without any seeding treatment.
Effect of Mn substitution on crystal structure and magnetic properties of Bi1−xPrxFeO3 multiferroics
Authors: Khomchenko V A , Troyanchuk I O , Kovetskaya M I , Kopcewicz M , Paixão J A
Published: January 2012

Mn substitution-driven structural and magnetic phase evolution in the predominantly antiferromagnetic polar rhombohedral (space group R3c) and weak ferromagnetic antipolar orthorhombic (space group Pnam) phases of the Bi1−x
Pr
x
FeO3 perovskites was studied by x-ray diffraction, 57Fe Mössbauer spectroscopy and magnetometry techniques at room temperature. Mn doping was found to effectively modify both the initial structures to stabilize a new phase demonstrating incommensurable modulation. Magnetic behaviour of the Mn-containing samples changes in correlation with the evolution of their structural state. Within the compositional range of the rhombohedrally distorted compounds, the manganese substitution gives rise to suppression of the dominant antiferromagnetic interaction. In the weak ferromagnetic doping-induced phase, a gradual decrease in room temperature spontaneous magnetization takes place with increasing Mn content.
Optical properties of zinc nitride films deposited by the rf magnetron sputtering method
Authors: Jayatissa Ahalapitiya H , Wen Ting , Gautam Madhav
Published: January 2012

Photoconductivity of zinc nitride films prepared by the reactive radio frequency (rf) magnetron sputtering method is reported. It was observed that the as-deposited zinc nitride films did not exhibit photoconductivity whereas the annealed films under ambient conditions above 275 °C indicated some photoconductivity. The photoconductivity of annealed zinc nitrides exhibited at a measurement temperature as high as 100 °C suggesting that the carrier generation was governed by band gap transition. Photoconductivity was observed for the films annealed in air while the films annealed in nitrogen and ammonia ambient did not exhibit any photoconductive phenomenon. The results indicate that the content of nitrogen in the zinc nitride films plays an important role in electronic properties. The effect of annealing on photoconductivity was interpreted as due to the removal of extra nitrogen, which was included in the films during the sputter deposition process.
Ultrafast Carrier Dynamics in CdSe/CdS/ZnS Quantum Dots
Authors: Yao Guan-xin , Fu Zai-xi , Zhang Xian-yi , Zheng Xian-feng , Ji Xue-han , Cui Zhi-feng , Zhang Hong
Published: January 2012

The intra- and inter-band relaxation dynamics of CdSe/CdS/ZnS core/shell/shell quantum dots are investigated with the aid of time-resolved nonlinear transmission spectra which are obtained using femtosecond pump-probe technique. By selectively exciting the core and shell carrier, the dynamics are studied in detail. Carrier relaxation is found faster in the conduction band of the CdS shell (about 130 fs) than that in the conduction band of the CdSe core (about 400 fs). From the experiments it is distinctly demonstrated the existence of the defect states in the interface between the CdSe core and the CdS shell, indicating that ultrafast spectroscopy might be a suitable tool in studying interface and surface morphology properties in nanosystems.
Electrochemistry of ABTS at Glassy Carbon Electrodes
Authors: Zeng Han , Tang Zhi-qiang , Liao Ling-wen , Kang Jing , Chen Yan-xia
Published: January 2012

The electrochemical and the mass transport behavior of ABTS2−/ABTS.− (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate)) redox couple at glassy carbon electrode (GCE) in phosphate buffer solution (PBS, pH=4.4) is studied in detail by cyclic voltammetry combined with rotating disk electrode system. From the i-E curves recorded at different electrode rotating rate, rate constant, and transfer coefficient for ABTS 2− ⇌ ABTS.−+e reaction at GCE electrode and the diffusion coefficient of ABTS2− in PBS are estimated to be 4.6 × 10−3 cm/s, 0.28, and 4.4 × 10−6 cm2/s, respectively. The transfer coefficient with a value of ca. 0.28 differs largely from the value of 0.5 that is always assumed in the literature. The origins for the difference of the rate constant determined and the challenges for estimating the standard rate constant are discussed. The performance for such ABTS2− mediated bio-cathode toward oxygen reduction reaction is discussed according to the over-potential drop as well as current output limit associated with the charge transfer kinetics of ABTS2− ⇌ ABTS.−+e redox reaction and/or the mass transport effect.
Self-assembly of α-6T Molecule on Ag(100) and Related STM Induced Luminescence
Authors: Chen Liu-guo , Zhang Chao , Zhang Rui , Dong Zhen-chao
Published: January 2012

We have investigated the self-assembly and light emission properties of organic α-sexithiophene (α-6T) molecules on Ag(100) under different coverage by scanning tunneling microscopy (STM). At very low coverage, the α-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure. As the coverage is increased, α-6T molecules tend to pack side by side into a denser stripe structure. Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag(100) with the lower-layer stripe pattern serving as a template. Molecular fluorescence for α-6T molecules on Ag(100) at a coverage of five monolayers has been detected by light excitations, which indicates a well decoupled electronic states for the top-layer α-6T molecules. However, the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission. The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules. For intramolecular fluorescence to occur, the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.
Isotopic Effects on Stereodynamics for Ca+HCl, Ca+DCl, and Ca+TCl Reactions
Authors: Wang Li-zhi , Yang Chuan-lu , Liang Jing-juan , Xiao Jing , Zhang Qing-gang
Published: January 2012

The vector correlations in Ca+HCl, Ca+DCl, and Ca+TCl reactions have been investigated by means of the quasi-classical trajectory calculations on PES constructed by means of multireference configuration interaction. The distributions of P(θr), P(φr) and the PDDCSs of (2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt), (2π/σ)(dσ21−/dωt) have been calculated based on the surface. The remarkable isotopic effects in the reactions are observed, and the mechanism which may be ascribed to different mass factors is discussed.
All-atom Molecular Dynamics Simulationsand NMR Spectroscopy Study on Interactions and Structures inN-Glycylglycine Aqueous Solution
Authors: Zhang Rong , Wu Wen-juan , Huang Jing-man , Meng Xin
Published: January 2012

All-atom molecular dynamics (MD) simulation and the NMR spectra are used to investigate the interactions in N-glycylglycine aqueous solution. Different types of atoms exhibit different capability in forming hydrogen bonds by the radial distribution function analysis. Some typical dominant aggregates are found in different types of hydrogen bonds by the statistical hydrogen-bonding network. Moreover, temperature-dependent NMR are used to compare with the results of the MD simulations. The chemical shifts of the three hydrogen atoms all decrease with the temperature increasing which reveals that the hydrogen bonds are dominant in the glycylglycine aqueous solution. And the NMR results show agreement with the MD simulations. All-atom MD simulations and NMR spectra are successful in revealing the structures and interactions in the N-glycylglycine-water mixtures.
First Principles Study of the Electronic and Magnetic Properties of Ce Doped SrMnO3
Authors: Luo Ben-hua , Wang Xue-ye , Zhang Yu , Xia Yong
Published: January 2012

The electronic and magnetic properties of Ce doped SrMnO3 have been investigated using the pseudo-potential plane wave method within the generalized gradient approximation method by first principles. The different Mn—O bond lengths indicate that there is a strong Jahn-Teller distortion of the MnO6 octahedron, which associates with a structural phase transition from cubic symmetry (Pm3̄m) to tetragonal symmetry (I4/mcm), and the Jahn-Teller ordering stabilizes a chain like (C-type) antiferromagnetic ground state. The electronic structures indicate that SrMnO3 and Sr1−xCexMnO3 (x = 0.125 and 0.25) are semiconductor and metallic, respectively. The doping of SrMnO3 with cerium induces simultaneously a decrease in the electrical resistivity, which can be attributed to the formation of Mn3+ as a result of charge compensation. The density of states and charge density map present that hybridization exists between some of O bands with those of Mn and Ce bands, the bonding between Sr and O is mainly ionic. Density of states and magnetic moment calculations show that the formal valence state of the Ce ion is trivalence.
Elastic Tensor and Thermodynamic Property of Magnesium Silicate Perovskite from First-principles Calculations
Authors: Liu Zi-jiang , Sun Xiao-wei , Zhang Cai-rong , Hu Jian-bo , Song Ting , Qi Jian-hong
Published: January 2012

The thermodynamic and elastic properties of magnesium silicate (MgSiO3) perovskite at high pressure are investigated with the quasi-harmonic Debye model and the first-principles method based on the density functional theory. The obtained equation of state is consistent with the available experimental data. The heat capacity and the thermal expansion coefficient agree with the observed values and other calculations at high pressures and temperatures. The elastic constants are calculated using the finite strain method. A complete elastic tensor of MgSiO3 perovskite is determined in the wide pressure range. The geologically important quantities: Young's modulus, Poisson's ratio, Debye temperature, and crystal anisotropy, are derived from the calculated data.
Structure and Magnetism of Co-implanted TiO2
Authors: Ding Bin-feng
Published: January 2012

Crystalline Co nanocomposites in the rutile TiO2 were synthesized by 180 keV Co ion beam implantation at temperature of 623 K with the fluence of 4×1016 cm−2. The structural and magnetic properties of samples with different thermal treatment were characterized by synchrotron radiation X-ray diffraction (SR-XRD), high resolution transmission electron microscopy (HRTEM), Rutherford backscattering/channeling and the superconducting quantum interference device magnetometer. The SR-XRD results reveal the formation of hcp and fcc phases of Co clusters, and the SR-XRD and HRTEM show that Co nanocrystals (NCs) have been formed in TiO2 after ion implantation. With increasing of annealing temperature, the transition of hcp to fcc Co is observed, and the Co NCs sizes were increased with increasing post-annealing temperature. At annealing temperature 1073 K, the lattice damaged is significantly removed compared with the virgin sample. The Co NCs forming inside TiO2 are the major contribution of the measured ferromagnetism.
NO Adsorption on Ag/Pt(110)-(1×2) Bimetallic Surfaces: Unexpected Formation of Nitrite/nitrate Surface Species
Authors: Li Jin-bing , Jiang Zhi-quan , Huang Wei-xin
Published: January 2012

NO adsorption on Ag/Pt(110)-(1×2) bimetallic surfaces at room temperature was investigated by means of Auger electron spectroscopy, X-ray photoelectron spectroscopy and thermal desorption spectroscopy. An unexpected formation of nitrite/nitrate surface species on Ag/Pt(110)-(1×2) bimetallic surfaces is observed, then decompose at elevated temperatures to form N2. However, such nitrite/nitrate surface species do not form on clean Pt(110) and Ag-Pt alloy surfaces upon NO exposure at room temperature. The formation of nitrite/nitrate surface species on Ag/Pt(110)-(1×2) bimetallic surfaces is attributed to high reactivity of highly coordination-unsaturated Ag clusters and the synergetic effect between Ag clusters and Pt substrate.
Highly Efficient Synthesis of Clean Biofuels from Biomass Using FeCuZnAlK Catalyst
Authors: Qiu Song-bai , Xu Yong , Ye Tong-qi , Gong Fei-yan , Yang Zhi , Yamamoto Mitsuo , Liu Yong , Li Quan-xin
Published: January 2012

Highly efficient synthesis of clean biofuels using the bio-syngas obtained from biomass gasification was performed over Fe1.5Cu1Zn1Al1K0.117 catalyst. The maximum biofuel yield from the bio-syngas reaches about 1.59 kg biofuels/(kgcatal·h) with a contribution of 0.57 kg alcohols/(kgcatal·h) and 1.02 kg liquid hydrocarbons/(kgcatal·h). The alcohol products in the resulting biofuels were dominated by the C2+ alcohols (mainly C2—C6 alcohols) with a content of 73.55%–89.98%. The selectivity of the liquid hydrocarbons (C5+) in the hydrocarbon products ranges from 60.37% to 70.94%. The synthesis biofuels also possess a higher heat value of 40.53–41.49 MJ/kg. The effects of the synthesis conditions, including temperature, pressure, and gas hourly space velocity, on the biofuel synthesis were investigated in detail. The catalyst features were characterized by inductively coupled plasma and atomic emission spectroscopy, X-ray diffraction, temperature programmed reduction, and the N2 adsorption-desorption isotherms measurements. The present biofuel synthesis with a higher biofuel yield and a higher selectivity of liquid hydrocarbons and C2+ alcohols may be a potentially useful route to produce clean biofuels and chemicals from biomass.
Recent data suggest no further recovery in North Sea Large Fish Indicator
Authors: Fung Tak , Farnsworth Keith D. , Reid David G. , Rossberg Axel G.
Published: January 2012

Fung, T., Farnsworth, K. D., Reid, D. G., Rossberg, A. G. 2012. Recent data suggest no further recovery in North Sea Large Fish Indicator. – ICES Journal of Marine Science, 69: 235–239. We detail the calculations of North Sea Large Fish Indicator values for 2009–2011, demonstrating an apparent stall in recovery. Therefore, recovery to the Marine Strategy Framework Directive's good environmental status of 0.3 by the 2020 deadline now looks less certain and may take longer than was expected using data from 2006 to 2008.
Single prolonged stress disrupts retention of extinguished fear in rats
Authors: Knox Dayan , George Sophie A. , Fitzpatrick Christopher J. , Rabinak Christine A. , Maren Stephen , Liberzon Israel
Published: January 2012

Clinical research has linked post-traumatic stress disorder (PTSD) with deficits in fear extinction. However, it is not clear whether these deficits result from stress-related changes in the acquisition or retention of extinction or in the regulation of extinction memories by context, for example. In this study, we used the single prolonged stress (SPS) animal model of PTSD and fear conditioning procedures to examine the effects of prior traumatic stress on the acquisition, retention, and context-specificity of extinction. SPS administered one week prior to fear conditioning had no effect on the acquisition of fear conditioning or extinction but disrupted the retention of extinction memories for both contextual and cued fear. This SPS effect required a post-stress incubation period to manifest. The results demonstrate that SPS disrupts extinction retention, leading to enhanced fear renewal; further research is needed to identify the neurobiological processes through which SPS induces these effects.
Plant Defense Mechanisms Are Activated during Biotrophic and Necrotrophic Development of Colletotricum graminicola in Maize
Authors: Vargas Walter A. , Martín José M. Sanz , Rech Gabriel E. , Rivera Lina P. , Benito Ernesto P. , Díaz-Mínguez José M. , Thon Michael R. , Sukno Serenella A.
Published: January 2012

Hemibiotrophic plant pathogens first establish a biotrophic interaction with the host plant and later switch to a destructive necrotrophic lifestyle. Studies of biotrophic pathogens have shown that they actively suppress plant defenses after an initial microbe-associated molecular pattern-triggered activation. In contrast, studies of the hemibiotrophs suggest that they do not suppress plant defenses during the biotrophic phase, indicating that while there are similarities between the biotrophic phase of hemibiotrophs and biotrophic pathogens, the two lifestyles are not analogous. We performed transcriptomic, histological, and biochemical studies of the early events during the infection of maize (Zea mays) with Colletotrichum graminicola, a model pathosystem for the study of hemibiotrophy. Time-course experiments revealed that mRNAs of several defense-related genes, reactive oxygen species, and antimicrobial compounds all begin to accumulate early in the infection process and continue to accumulate during the biotrophic stage. We also discovered the production of maize-derived vesicular bodies containing hydrogen peroxide targeting the fungal hyphae. We describe the fungal respiratory burst during host infection, paralleled by superoxide ion production in specific fungal cells during the transition from biotrophy to a necrotrophic lifestyle. We also identified several novel putative fungal effectors and studied their expression during anthracnose development in maize. Our results demonstrate a strong induction of defense mechanisms occurring in maize cells during C. graminicola infection, even during the biotrophic development of the pathogen. We hypothesize that the switch to necrotrophic growth enables the fungus to evade the effects of the plant immune system and allows for full fungal pathogenicity.
Reverse Monte Carlo refinements of nanoscale atomic correlations using powder and single-crystal diffraction data
Authors: Krayzman Victor , Levin Igor
Published: January 2012

Combined refinements of local atomic structure that involve simultaneous fitting of powder-averaged and single-crystal data were implemented as an extension to the publicly availableRMCProfilesoftware. The refinements employ the reverse Monte Carlo method to fit neutron total scattering data, the neutron Bragg profile, extended X-ray absorption fine structure (EXAFS) and structured diffuse scattering in electron diffraction. The procedure was tested using simulated data generated for a realistic model of perovskite-like KNbO3, which exhibits strongly correlated Nb and O displacements. The results indicated that fitting the powder data (i.e.total scattering or total scattering plus EXAFS) alone fails to reproduce the nanoscale range of displacement correlations. Simultaneous fitting of the powder data and the patterns of diffuse intensity in single-crystal electron diffraction patterns returns significantly more accurate correlation characteristics. The approach and the computer software described in this contribution are not limited to electron diffraction patterns as other types of single-crystal diffraction data (i.e.X-ray or neutron) can be included in the fit.
Early development of New Zealand hapuku Polyprion oxygeneios eggs and larvae
Authors: Anderson S. A. , Salinas I. , Walker S. P. , Gublin Y. , Pether S. , Kohn Y. Y. , Symonds J. E.
Published: January 2012

This study describes for the first time the normal development of New Zealand hapuku Polyprion oxygeneios embryos and larvae reared from fertilization to 11 days post‐hatch (dph) at a constant temperature. Fertilized eggs were obtained from natural spawnings from communally reared captive wild broodstock. Eggs averaged 2 mm in diameter and had single or multiple oil globules. Embryos developed following the main fish embryological stages and required an average of 1859·50 degree hours post‐fertilization (dhpf) to hatch. The newly hatched larvae (4·86 mm mean total length, LT) were undifferentiated, with unpigmented eyes, a single and simple alimentary tube and a finfold that covered the entire body. Larvae relied on the energy from the yolk‐sac reserves until 11 dph (7·33 mm mean LT), when yolk‐sac reabsorption was almost completed. Some of the major developmental stages from hatching to yolk‐sac reabsorption were eye pigmentation (5 dph), upper jaw formation (7 dph), lower jaw formation (8 dph) and mouth opening (8–9 dph). By 9 dph, the digestive system consisted of pancreas, liver, primordial stomach, anterior and posterior gut; therefore, P. oxygeneios larvae would be capable of feeding on live prey. The developmental, morphological and histological data described constitutes essential baseline information on P. oxygeneios biology and normal development.
Concomitant use of clopidogrel and statins and risk of major adverse cardiovascular events following coronary stent implantation
Authors: Schmidt Morten , Johansen Martin B. , Maeng Michael , Kaltoft Anne , Jensen Lisette O. , Tilsted Hans‐Henrik , Bøtker Hans E. , Baron John A. , Sørensen Henrik Toft
Published: January 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The CYP3A4 inhibition by lipophilic statins may attenuate the effectiveness of clopidogrel.

• No studies have measured drug exposure in a time‐varying manner that detects discontinuation and restart of clopidogrel and statin therapy, allowing clinical quantification of the interaction effect.

WHAT THIS STUDY ADDS

• Clopidogrel and CYP3A4‐metabolizing statin use were each associated with a substantially reduced rate of major adverse cardiovascular events within 12 months after coronary stent implantation.

• Although we observed an interaction between use of clopidogrel and statins, statin use vs. non‐use was not associated with an increased rate of major adverse cardiovascular events in patients using clopidogrel after coronary stent implantation.

AIMS To examine whether CYP3A4‐metabolizing statin use modified the association between clopidogrel use and major adverse cardiovascular events (MACE) after coronary stent implantation, using time‐varying drug exposure ascertainment.

METHODS We conducted this population‐based cohort study in Western Denmark (population: 3 million) using medical databases. We identified all 13 001 patients with coronary stent implantation between 2002 and 2005 and their comorbidities. During 12 months of follow‐up, we tracked the use of clopidogrel and CYP3A4‐metabolizing statins and the rate of MACE. We used Cox regression to compute hazard ratios (HRs) controlling for potential confounders.

RESULTS The rate of MACE per 1000 person years was 104 for concomitant clopidogrel and statin use, 130 for clopidogrel without statin use, 108 for statin without clopidogrel use and 446 for no use of either drug. The adjusted HR comparing clopidogrel use with non‐use was 0.68 (95% confidence interval (CI) 0.58, 0.79) among statin users and 0.34 (95% CI 0.29, 0.40) among statin non‐users, yielding an interaction effect (i.e. relative rate increase) of 1.97 (95% CI 1.59, 2.44). The adjusted HR for MACE comparing statin use with non‐use was 0.97 (95% CI 0.83, 1.13) among clopidogrel users and 0.49 (95% CI 0.42, 0.57) among clopidogrel non‐users.

CONCLUSIONS Clopidogrel and CYP3A4‐metabolizing statin use were each associated with a substantially reduced rate of MACE within 12 months after coronary stent implantation. Although we observed an interaction between use of clopidogrel and statins, statin use vs. non‐use was not associated with an increased rate of MACE in patients using clopidogrel after coronary stent implantation.
Bioequivalence of two omega‐3 fatty acid ethyl ester formulations: a case of clinical pharmacology of dietary supplements
Authors: Galli Claudio , Maggi Franco M. , Risé Patrizia , Sirtori Cesare R.
Published: January 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Omega‐3 fatty acids are dietary components, present in the body with variable blood concentrations.

• Bioavailability evaluations of ethyl ester preparations are hampered by the difficulty in achieving similar concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the preparations being compared. This may require questionable corrections for baseline concentrations.

• If repeated doses are given, this may lead to errors because of variable dietary fish intake. If a single dose is selected, this needs to be large, since omega‐3 LC‐PUFA are present in many compartments.

WHAT THIS STUDY ADDS

• We selected subjects with uniform omega‐3 background concentrations, to obtain comparable results at the end of treatment.

• Testing bioequivalence of two formulations with different EPA : DHA ratios led to single dose intakes of 12 g, which were well tolerated.

• In spite of clear differences in EPA : DHA ratios between the two preparations, plasma ratios did not differ and bioequivalence could be well ascertained.

AIM To evaluate the bioequivalence of two omega‐3 long chain polyunsaturated fatty acid (n‐3 LC‐PUFA) ethyl ester preparations, previously shown not to be bioequivalent in healthy subjects, with the objective of providing a guideline for future work in this area.

METHOD A randomized double‐blind crossover protocol was chosen. Volunteers with the lowest blood concentrations of n‐3 LC‐PUFA were selected. They received the ethyl esters in a single high dose (12 g) and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) blood concentrations were analyzed after fingerprick collection at intervals up to 24 h.

RESULTS Differently from a prior study, the pharmacokinetic analysis indicated a satisfactory bioequivalence: for the AUC(0,24 h) 90% CI of the ratio between the two formulations were in the range for bioequivalence (for EPA 0.98, 1.04 and for DHA 0.99, 1.04) and the same was true for Cmax and tmax (90% CI were 0.95, 1.14 and 1.10, 1.25 for EPA and 0.88, 1.02 and 0.84, 1.24 for DHA).

CONCLUSION This study shows that, in order to obtain reliable bioequivalence data of products present in the daily diet, certain conditions should be met. Subjects should have low, homogeneous baseline concentrations and not be exposed to food items containing the product under evaluation, e.g. fish. Finally, as in the case of omega‐3 fatty acids, selected doses should be high, eventually with appropriate conditions of intake.
Changes of blood endocannabinoids during anaesthesia: a special case for fatty acid amide hydrolase inhibition by propofol?
Authors: Jarzimski Carina , Karst Matthias , Zoerner Alexander A. , Rakers Christin , May Marcus , Suchy Maria T. , Tsikas Dimitrios , Krauss Joachim K. , Scheinichen Dirk , Jordan Jens , Engeli Stefan
Published: January 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Available data from animal studies suggest that the narcotic drug propofol interacts with the endocannabinoid system. Inhibition of enzymatic degradation of anandamide could explain some of the characteristics of propofol. Direct measurements have not been reported yet in humans.

WHAT THIS STUDY ADDS

• Propofol does not change the time course of anandamide plasma concentrations during anaesthesia. Furthermore, propofol does not inhibit fatty acid amide hydrolase activity ex vivo or in vitro. Thus, specific characteristics of the narcotic drug propofol cannot be explained by peripheral inhibition of anandamide degradation in humans.

AIMS The aim of our study was to describe the time course of endocannabinoids during different anaesthesia protocols in more detail, and to challenge the hypothesis that propofol acts as a FAAH inhibitor.

METHODS Endocannabinoids were measured during the first hour of anaesthesia in 14 women and 14 men undergoing general anaesthesia with propofol and in 14 women and 14 men receiving thiopental/sevoflurane. We also incubated whole human blood samples ex vivo with propofol and the known FAAH inhibitor oloxa and determined FAAH enzyme kinetics.

RESULTS Plasma anandamide decreased similarly with propofol and thiopental/sevoflurane anaesthesia, and reached a nadir after 10 min. Areas under the curve for anandamide (mean and 95% CI) were 53.3 (47.4, 59.2) nmol l−1 60 min with propofol and 48.5 (43.1, 53.8) nmol l−1 60 min with thiopental/sevoflurane (P= NS). Anandamide and propofol plasma concentrations were not correlated at any time point. Ex vivo FAAH activity was not inhibited by propofol. Enzyme kinetics (mean ± SD) of recombinant human FAAH were Km= 16.9 ± 8.8 µmol l−1 and Vmax= 44.6 ± 15.8 nmol mg–1 min–1 FAAH without, and Km= 16.6 ± 4.0 µmol l−1 and Vmax= 44.0 ± 7.6 nmol mg–1 min−1 FAAH with 50 µmol l−1 propofol (P= NS for both).

CONCLUSIONS Our findings challenge the idea that propofol anaesthesia and also propofol addiction are directly mediated by FAAH inhibition, but we cannot exclude other indirect actions on cannabinoid receptors.
Use of dicarboxylic acids in type 2 diabetes
Authors: Mingrone Geltrude , Castagneto‐Gissey Lidia , Macé Katherine
Published: January 2012

Even‐number, medium‐chain dicarboxylic acids (DAs), naturally occurring in higher plants, are a promising alternative energy substrate. Unlike the homologous fatty acids, DAs are soluble in water as salts. They are β‐oxidized, providing acetyl‐CoA and succinyl‐CoA, the latter being an intermediate of the tricarboxylic acid cycle. Sebacic acid and dodecanedioic acid, DAs with 10 and 12 carbon atoms respectively, provide 6.6 and 7.2 kcal g−1 each; therefore, their energy density is intermediate between glucose and fatty acids. Dicarboxylic acids have been proved to be safe in both experimental animals and humans, and their use has recently been proposed in diabetes. Studies in animals and humans with type 2 diabetes showed that oral administration of sebacic acid improved glycaemic control, probably by enhancing insulin sensitivity, and reduced hepatic gluconeogenesis and glucose output. Moreover, dodecanedioic acid intake reduced muscle fatigue during exercise in subjects with type 2 diabetes, suggesting an improvement of energy utilization and ‘metabolic flexibility’. In this article, we review the natural sources of DAs, their fate in animals and humans and their effect in improving glucose metabolism in type 2 diabetes.
Selenium status and allergic disease in a cohort of New Zealand children
Authors: Thomson C. D. , Wickens K. , Miller J. , Ingham T. , Lampshire P. , Epton M. J. , Town G. I. , Pattemore P. , Crane J.
Published: January 2012

Background

New Zealand has one of the highest rates of asthma and atopy. Selenium has been implicated in the aetiology of asthma, and associations between low selenium status and asthma in New Zealand children have been reported.

Objective

The aim was to investigate the association between selenium status and allergic disease in a birth cohort of New Zealand children.

Methods

The New Zealand Asthma and Allergy Cohort Study is a prospective birth cohort in Wellington and Christchurch, involving 1105 infants born 1997–2001. During the 6‐year assessment (n = 635), associations were investigated between plasma selenium (PlSe) and whole blood glutathione peroxidase activity (WBGPx) and allergy‐related health outcomes including asthma, wheeze, hayfever, rhinitis, eczema and rash.

Results

Wellington children had greater PlSe and WBGPx than Christchurch children (P < 0.001 for both). PlSe (P = 0.004) and WBGPx (P = 0.03) were lower in children exposed to environmental smoke, but differences were no longer significant after adjustment for study location, current household smoking (5–6 years), maternal smoking during pregnancy, family history (either parent with asthma, eczema or hayfever), prioritized ethnicity (Maori, Pacific peoples, Other, European), gender, season born, number of siblings, New Zealand Deprivation Index and body mass index at 6 years. Analysis of PlSe or WBGPx as continuous variables or of quartiles of PlSe with health outcomes showed no significant associations after adjustment. Univariate analysis of quartiles of PlSe and WBGPx with persistent wheeze showed significant inverse trends (P = 0.005 for both), but these reduced after adjustment.

Conclusions and Clinical Relevance

Our results do not support a strong association between selenium status and the high incidence of asthma in New Zealand. However, there was a modest association between lower PlSe and WBGPx activity and higher incidence of persistent wheeze.
Degrees of disruption: projected temperature increase has catastrophic consequences for reproduction in a tropical ectotherm
Authors: Zeh Jeanne A. , Bonilla Melvin M. , Su Eleanor J. , Padua Michael V. , Anderson Rachel V. , Kaur Dilpreet , Yang Dou‐shuan , Zeh David W.
Published: January 2012

Although climate change models predict relatively modest increases in temperature in the tropics by the end of the century, recent analyses identify tropical ectotherms as the organisms most at risk from climate warming. Because metabolic rate in ectotherms increases exponentially with temperature, even a small rise in temperature poses a physiological threat to tropical ectotherms inhabiting an already hot environment. If correct, the metabolic theory of climate warming has profound implications for global biodiversity, since tropical insects and arachnids constitute the vast majority of animal species. Predicting how climate change will translate into fitness consequences for tropical arthropods requires an understanding of the effects of temperature increase on the entire life history of the species. Here, in a comprehensive case study of the fitness consequences of the projected temperature increase for the tropics, we conducted a split‐brood experiment on the neotropical pseudoscorpion, Cordylochernes scorpioides, in which 792 offspring from 33 females were randomly assigned at birth to control‐ and high‐temperature treatments for rearing through the adult stage. The diurnally varying, control treatment temperature was determined from long‐term, average daily temperature minima and maxima in the pseudoscorpion's native habitat. In the high temperature treatment, increasing temperature by the 3.5 °C predicted for the tropics significantly reduced survival and accelerated development at the cost of reduced adult size and a dramatic decrease in level of sexual dimorphism. The most striking effects, however, involved reproductive traits. Reared at high temperature, males produced 45% as many sperm as control males, and females failed to reproduce. Sequencing of the mitochondrial ND2 gene revealed two highly divergent haplogroups that differed substantially in developmental rate and survivorship but not in reproductive response to high temperature. Our findings suggest that reproduction may be the Achilles’ heel of tropical ectotherms, as climate warming subjects them to an increasingly adverse thermal environment.
Past, present and future of mountain species of the French Massif Central – the case of Soldanella alpina L. subsp. alpina (Primulaceae) and a review of other plant and animal studies
Authors: Kropf Matthias , Comes Hans Peter , Kadereit Joachim W.
Published: January 2012

Aim  Our goals were: (1) to investigate patterns of genetic variation in the French Massif Central (MC) of Soldanella alpina (Primulaceae), an alpine plant species that has only one known population in the region; (2) to analyse these patterns in order to deduce the Quaternary history of the population and to predict how current climatic warming may affect it; and (3) to review molecular analyses from the MC to evaluate the importance of the region for the conservation of genetic diversity.

Location  Europe, with a special focus on the French Massif Central and adjacent regions.

Methods  Amplified fragment length polymorphisms (AFLPs) were analysed for 192 individuals (nine populations) of S. alpina (subsp. alpina) representing the MC, Pyrenees and south‐western Alps. Population genetic diversity was assessed by various parameters (e.g. HE, Shannon’s I). Neighbor‐Net and Bayesian approaches, and analysis of molecular variance (AMOVA) were used to infer population genetic relationships and structure.

Results  Individuals generally clustered according to populations within mountain regions. Hierarchical AMOVA indicated significant variation among mountain ranges (33.2% of the total variance), but there was also strong differentiation between populations (26.3%). The single population of S. alpina from the MC was identified as a distinct lineage of high genetic diversity. Our literature survey indicated that taxa with low and with high genetic diversity exist in the MC, and that genetic relationships to surrounding regions are diverse.

Main conclusions  The high genetic diversity and distinctiveness of S. alpina in the MC suggests the long‐term persistence of the single population in this region, which might have been favoured through elevational range shifts in response to past climatic change. This interpretation partly accords with other studies indicating that several plant and animal populations in the MC contain comparatively high genetic diversity, represent genetically independent lineages, and/or are likely descendants of populations that persisted in the MC throughout the Quaternary. These data underline the conservation importance of the MC as a key area for the long‐term persistence of species with often high levels of intraspecific genetic diversity.
Differences in clinical reasoning among nurses working in highly specialised paediatric care
Authors: Andersson Nina , Klang Birgitta , Petersson Gunilla
Published: January 2012

Aims and objectives.  The aim of the study was to examine differences in clinical reasoning among novice, experienced and specialist paediatric nurses.

Background.  Highly specialised paediatric care requires specific knowledge and ongoing skill performance of the nurses employed. There is a lack of research in how paediatric nurses manage the daily care problems they encounter and how they acquire the skills required to give patients the best possible care. More knowledge is needed about how paediatric nurses with different experience and education reason and communicate about paediatric patient situations.

Design.  The study was based on six recorded group discussions of a fictitious, but realistic paediatric case. Three categories of nurses: novices (n = 7), experienced (n = 7) and specialists (n = 7) from a paediatric hospital participated. A qualitative content analysis approach was chosen to examine differences in clinical reasoning.

Results.  Several themes were uncovered: child’s social situation, child abuse and the child’s illness, qualitative differences emerged in how the nurses discussed the case. Three approaches were identified: a task‐oriented approach (novices and experienced), an action‐oriented approach (novices and experienced) and hypothesis‐oriented approach (specialists) while discussing the case.

Conclusion.  When comparing nurses in three competence groups, it was established that the groups with extensive experience and specialist education reasoned differently than the other groups. Between the novice and experienced groups, no obvious differences were found. Thus, the importance of experience alone for the development of competence is still an open question. Experience combined with further education appears important for developing professional competence in paediatric care.

Relevance to clinical practice.  Nurses’ reasoning in clinical paediatric care is related to experience and training.
Retracted: The impact of nurse short message services and telephone follow‐ups on diabetic adherence: which one is more effective?
Authors: Zolfaghari Mitra , Mousavifar Seyedeh A , Pedram Shadan , Haghani Hamid
Published: January 2012

Aim.  To compare the effectiveness of two methods of follow‐up: short message service and telephone follow‐up on type 2 diabetes adherence for three months.

Background.  Using telemedicine approaches may preserve appropriate blood glucose levels and may improve adherence to diabetes control recommendations in diabetic patients.

Design.  A quasi‐experimental, two‐group, pretest and post‐test design was used in this study to evaluate the effectiveness of nurse’s follow‐up via cellular phones and telephones.

Methods.  The sample consisted of 77 patients with type 2 diabetes that randomly were assigned to two groups: telephone follow‐up (n = 39) and short message service (n = 38). Telephone interventions were applied by a researcher for three months; twice a week for the first month and every week for the second and third month. For three successive months, the short message service group that received messages about adherence to therapeutic regimen was examined. The data gathering instrument included data sheets – to record glycosylated haemoglobin – and the questionnaire related to adherence therapeutic regimen. Data gathering was carried out at the beginning of the study and after three and six months. The data were analysed using descriptive and inferential statistic methods with SPSS version 11.5.

Results.  Results showed that both interventions had significant mean changes in glycosylated haemoglobin. For the telephone group (p < 0·001), a mean change of −0·93 and for the short message service group (p < 0·001), a mean change of −1·01. There was no significant difference in diet adherence (p = 0·000), physical exercise (p = 0·000) and medication taking (p = 0·000) adherence in either groups.

Conclusion.  Intervention using short message services of cellular phones and nurse‐led‐telephone follow‐up improved HbA1c levels and adherence to diabetes therapeutic regimen for three months in type 2 diabetic patients.

Relevance to clinical practice.  Both of follow‐up intervention uses in this study can decrease HbA1c levels and escalate adherence to diabetes control recommendations in people with type 2 diabetes for three months.