bluuebunny/crossref_metadata_2025 huggingface dataset:
Uncertainties in summer evapotranspiration changes over Europe and implications for regional climate change
Authors: Boé Julien , Terray Laurent
Published: March 2008

Changes in summer evapotranspiration over central and eastern Europe are very uncertain in the World Climate Research Programme's (WRCP) Coupled Model Intercomparison Project phase 3 (CMIP3) multi‐model data set. We show that the response of evapotranspiration in the future climate over this area is strongly linked to the way the models represent the respective role of soil moisture and radiative energy at surface on evapotranspiration at the interannual time scale in the present climate. Actually, the models for which the limiting effect of soil moisture upon evapotranspiration is already large in the present climate generally responds by a decrease of evapotranspiration whereas the other models generally exhibit an increase of evapotranspiration. The uncertainties in evapotranspiration changes seem to have an important impact in precipitation and temperature changes. Finally, we assess the realism of the controls of evapotranspiration in the CMIP3 models over France using a hydro‐meteorological simulation.
Formation of maximum electric potential at the geomagnetic equator by the disturbance dynamo
Authors: Huang C. M. , Chen M. Q.
Published: March 2008

The effect of a disturbance dynamo during geomagnetic activity on the equatorial ionospheric electric fields is investigated, using model results from the NACR/TIEGCM (National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model). Model runs are made for different time‐lengths of geomagnetic activity, for different seasons, and for different solar activities to investigate how and where the maximum electric potential forms. Model results show that the maximum electric potential is located at around 300 km altitude and at local time after the pre‐reversal enhancement at equinox for high solar activity. For the case at solstice, without pre‐reversal enhancement, the location moves to around 110 km altitude and to the local time close to midnight. Giving various parameters in the model runs to simulate different background conditions, many important output quantities are used to study the distributions of perturbed electric potential at the geomagnetic equator. Model investigation indicates that normal quiet time electrodynamics, at different seasons with different solar activities, significantly affect the distribution of perturbed current density associated with geomagnetic activity. Furthermore, model results also reveal that significant perturbed zonal electric fields tend to build up six hours after the onset of geomagnetic activity, except at regions close to sunset and sunrise, and the perturbed vertical electric fields increase with the time length of geomagnetic activity.
Tectonic implications of faulting styles along a rift margin: The boundary between the Rhine Graben and the Vosges Mountains
Authors: Rotstein Yair , Schaming Marc
Published: March 2008

Seismic reflection data show the effects of the Miocene strike‐slip environment on the boundary between the Upper Rhine Graben (URG) and the Vosges Mountains (VM). The border fault zone exhibits three types of responses to the new NW‐SE directed regional stress regime. Where it trends N‐S, no new deformation is observed. Where it trends NNE‐SSW, transpression is evident, and it develops into a few‐kilometers‐wide zone of intense deformation. Along the NE‐SW trending southern boundary of VM, transpression intensifies with an increase in the perpendicular shortening component, and the border fault zone turns into a reverse fault. The uplift of the boundary relative to the graben is estimated to be no less than 1000 m near Colmar, and significantly more along the boundary with the Dannemarie Basin. These estimates, and kinematics considerations, support the hypothesis that the Vosges Mountains are mostly a transpressional feature. The Rhine Fault is mapped and suggested to be a lower Miocene structure that was formed in response to the change in the regional stress regime.
Adenosine receptors and asthma
Authors: Brown R A , Spina D , Page C P
Published: March 2008

The accumulation of evidence implicating a role for adenosine in the pathogenesis of asthma has led to investigations into all adenosine receptor subtypes as potential therapeutic targets for the treatment of asthma. Selective A1receptor antagonists are currently in preclinical development since adenosine has been shown experimentally to mediate various features of asthma through this receptor such as bronchoconstriction, mucus secretion and inflammation. The A2Areceptor is expressed on most inflammatory cells implicated in asthma, and as A2Astimulation activates adenylate cyclase and consequently elevates cAMP, selective A2Areceptor agonists have now reached clinical development. However, initial reports concerning their efficacy are inconclusive. A2Breceptor antagonists are also under investigation based on the rationale that inhibiting the effects of adenosine on mast cells would be beneficial, in addition to other reported pro‐inflammatory effects mediated by the A2Breceptor on cells such as airway smooth muscle, epithelial cells and fibroblasts. Whilst the effects in pre‐clinical models are promising, their efficacy in the clinical setting has also yet to be reported. Finally, adenosine A3receptor stimulation has been demonstrated to mediate inhibitory effects on eosinophils since it also elevates cAMP. However, some experimental reports suggest that A3antagonists mediate anti‐inflammatory effects, thus the rationale for A3receptor ligands as therapeutic agents remains to be determined. In conclusion, establishing the precise role of adenosine in the pathogenesis of asthma and developing appropriate subtype selective agonists/antagonists represents an exciting opportunity for the development of novel therapeutics for the treatment of asthma.

British Journal of Pharmacology(2008)153, S446–S456; doi:10.1038/bjp.2008.22
Dose‐dependent protective effect of propofol against mitochondrial dysfunction in ischaemic/reperfused rat heart: role of cardiolipin
Authors: Shao H , Li J , Zhou Y , Ge Z , Fan J , Shao Z , Zeng Y
Published: March 2008

Background and purpose:

Ischaemia damages to the cardiac mitochondria by increasing generation of reactive oxygen species (ROS) and peroxidation of cardiolipin. The inhibited mitochondrial function leads to the cardiac injury during reperfusion. Propofol (2, 6‐diisopropylphenol), an intravenous anaesthetic, has been shown to decrease cardiac ischaemia and reperfusion injury. In the present study, we propose that propofol protects mitochondrial function and decreases cardiac injury by prevention of cardiolipin peroxidation during ischaemia and reperfusion.

Experimental approach:

After isolation of mitochondria from isolated rat heart perfused on a Langendorff model, various mitochondrial bioenergetic parameters were evaluated such as rates of mitochondrial oxygen consumption, H2O2 production, complex I and III activity as well as the degree of lipid peroxidation and cardiolipin content. The action of propofol was also explored in isolated mitochondria. And the effect of cardiolipin was evaluated by fusing cardiolipin liposome with mitochondria.

Key results:

Propofol treatment had strong dose‐dependent protection attenuating these parameters alterations in reperfused rat heart and isolated mitochondria. Additionally, cardiolipin treatment had the same protective effect, compared with propofol treatment at high concentration.

Conclusions and implications:

The protective effect of propofol appears to be due, at least in part, as a chemical uncoupler, to the interruption of the vicious circle of ROS–cardiolipin–complexes of the respiratory chain–ROS through preserving the content and integrity of cardiolipin molecules by ROS attack. These findings may provide an explanation for some of the factors responsible for cardioprotection and one approach exploring an available antioxidant.

British Journal of Pharmacology (2008) 153, 1641–1649; doi:10.1038/bjp.2008.45; published online 3 March 2008
Retinal plasma extravasation in streptozotocin‐diabetic rats mediated by kinin B1and B2receptors
Authors: Abdouh M , Talbot S , Couture R , Hasséssian H M
Published: March 2008

Background and purpose:We investigated whether or not kinin receptors play a role in diabetic blood–retinal barrier breakdown, which is a leading cause of vision loss.

Experimental approach:Blood–retinal barrier breakdown was quantified using Evans blue, and expression of kinin B1receptor mRNA was measured using quantitative reverse transcrition‐PCR. Diabetic rats (streptozotocin (STZ), 65 mg kg−1) received a single intraocular injection of bradykinin (BK) or des‐Arg9‐BK, alone, or in combination with antagonists for B1(des‐Arg10‐Hoe140, R‐715) and/or B2(Hoe140) receptors, given intraocularly or intravenously (i.v.).

Key results:In control rats, BK (0.1–10 nmol) dose‐dependently increased plasma extravasation, which was inhibited by Hoe140 (0.2 nmol), whereas des‐Arg9‐BK (0.1 and 1 nmol) was without effect. B1receptor mRNA was markedly increased in retinas of diabetic rats, and this was prevented byN‐acetyl‐L‐cysteine (1 g kg−1 day−1for 7 days). Plasma extravasation in retinas of STZ‐diabetic rats was higher than in controls and enhanced by des‐Arg9‐BK. Response to des‐Arg9‐BK was inhibited by intraocular or i.v. injection of B1receptor antagonists. Diabetes‐induced plasma extravasation was inhibited only by a combination of des‐Arg10‐Hoe140 and Hoe 140 (100 nmol kg−1, i.v. 15 min earlier) or by R‐715 (1 μmol kg−1, i.v.) injected daily for 7 days.

Conclusions and implications:Kinin B1receptors are upregulated in retinas of STZ‐diabetic rats through a mechanism involving oxidative stress. Both kinin B1and B2receptors contribute to increased plasma extravasation in diabetic retinopathy. Chronic inhibition of both kinin receptors, possibly with antioxidant adjuvants, may be a novel therapeutic strategy for diabetic retinopathy.
Second meiotic arrest and exit in frogs and mice
Authors: Perry Anthony C.F. , Verlhac Marie‐Hélène
Published: March 2008

Mature vertebrate oocytes typically undergo programmed arrest at the second meiotic cell cycle until they are signalled to initiate embryonic development at fertilization. Here, we describe the underlying molecular mechanisms of this second meiotic arrest and release in Xenopus, and compare and contrast them with their counterparts in mice.
Development of an all-permanent-magnet microwave ion source equipped with multicusp magnetic fields for high current proton beam production
Authors: Tanaka M. , Hara S. , Seki T. , Iga T.
Published: March 2008

An all-permanent-magnet (APM) microwave hydrogen ion source was developed to reduce the size and to simplify structure of a conventional solenoid coil microwave ion source developed for reliability improvement of high current proton linac application systems. The difficulty in developing the APM source was sensitive dependence of the source performance on axial magnetic field in the microwave discharge chamber. It was difficult to produce high current proton beam stably without precise tuning of the magnetic field using solenoid coils. We lowered the sensitivity using multicusp magnetic fields for plasma confinement at the discharge chamber sidewall of the source. This enabled stable high current proton beam production with the APM microwave ion source with no tuning coil. The water cooling and the power supply for the coils are not necessary for the APM source, which leads to better reliability and system simplification. The outer diameter of the APM source was around 300mm, which was 20% lower than the coil source. The APM source produced a maximum hydrogen ion beam current of 65mA (high current density of 330mA∕cm2, proton ratio of 87%, and beam energy of 30keV) with a 5mm diameter extraction aperture, pulse width of 400μs, and 20Hz repetition rate at 1.3kW microwave power. This performance is almost the same as the best performances of the conventional coil sources. The extracted ion beams were focused with electrostatic five-grid lens to match beam to acceptance of radio-frequency quadrupole linacs. The maximum focused beam current through the orifice (5mm radius) and the lens was 36mA and the 90% focused beam half-width was 1–2mm.
Density, distribution, and orientation of water molecules inside and outside carbon nanotubes
Authors: Thomas J. A. , McGaughey A. J. H.
Published: March 2008

The behavior of water molecules inside and outside 1.1, 2.8, 6.9, and 10.4nm diameter armchair carbon nanotubes (CNTs) is predicted using molecular dynamics simulations. The effects of CNT diameter on mass density, molecular distribution, and molecular orientation are identified for both the confined and unconfined fluids. Within 1nm of the CNT surface, unconfined water molecules assume a spatially varying density profile. The molecules distribute nonuniformly around the carbon surface and have preferred orientations. The behavior of the unconfined water molecules is invariant with CNT diameter. The behavior of the confined water, however, can be correlated to tube diameter. Inside the 10.4nm CNT, the molecular behavior is indistinguishable from that of the unconfined fluid. Within the smaller CNTs, surface curvature effects reduce the equilibrium water density and force water molecules away from the surface. This effect changes both the molecular distribution and preferred molecular orientations.
Vacuum switch performance in a 1.2MJ pulse forming network
Authors: Scholfield David W. , Butcher Michael D. , Hilko Brian , Dorr Greg
Published: March 2008

Vacuum switching has been used since the early days of pulsed power to provide a means to controlling the flow of large amounts of current. The attractions of vacuum switches for high energy switching are the vacuum mitigates mechanical shock generated by the discharge, low erosion rates, and rapid recovery for repetitive rate operations. Some of the drawbacks of vacuum switching are typically the requirement of a vacuum system and metal vapor sputtering which eventually renders the switch unusable. SAIC has developed a compact vacuum switch which is capable of conducting a current pulse in excess of 300kA peak for a duration of approximately 0.5ms. On a single shot, 150C have been switched while the amount of action seen by these switches has been as much as 3.65×107A2s. Switches of this design have been able to conduct up to 20 pulses of this magnitude before failure has occurred. The switch is triggerable down to 80V potential across the anode and cathode. This paper describes the development of this switch.
On spectra of Lüders operations
Authors: Nagy Gabriel
Published: March 2008

We show that all the eigenvalues of certain generalized Lüders operations are non-negative real numbers in two cases of interest. In particular, given a commuting n-tuple A=(A1,…,An) consisting of positive operators on a Hilbert space H, satisfying ∑j=1nAj=I, we show that the spectrum of the Lüders operation: ΛA:B(H)∋X↦∑j=1nAj1∕2XAj1∕2∈B(H) is contained in [0,∞), so the only solution of the equation ΛA(X)=I−X is the “expected” one: X=12I.
Stepped horn actuated Kelvin probe
Authors: Reboul J.-R. , Guasch C. , Ferrandis J.-Y. , Bonnet J.
Published: March 2008

We have developed an original Kelvin probe system using an ultrasonic stepped horn sonotrode. This actuator is optimized in order to maximize the velocity of the tip end, and hence to increase the Kelvin current detected. Such development is essential to improve surface potential measurements at small spatial scale.
Direct energy functional minimization under orthogonality constraints
Authors: Weber Valéry , VandeVondele Joost , Hutter Jürg , Niklasson Anders M. N.
Published: March 2008

The direct energy functional minimization problem in electronic structure theory, where the single-particle orbitals are optimized under the constraint of orthogonality, is explored. We present an orbital transformation based on an efficient expansion of the inverse factorization of the overlap matrix that keeps orbitals orthonormal. The orbital transformation maps the orthogonality constrained energy functional to an approximate unconstrained functional, which is correct to some order in a neighborhood of an orthogonal but approximate solution. A conjugate gradient scheme can then be used to find the ground state orbitals from the minimization of a sequence of transformed unconstrained electronic energy functionals. The technique provides an efficient, robust, and numerically stable approach to direct total energy minimization in first principles electronic structure theory based on tight-binding, Hartree–Fock, or density functional theory. For sparse problems, where both the orbitals and the effective single-particle Hamiltonians have sparse matrix representations, the effort scales linearly with the number of basis functions N in each iteration. For problems where only the overlap and Hamiltonian matrices are sparse the computational cost scales as O(M2N), where M is the number of occupied orbitals. We report a single point density functional energy calculation of a DNA decamer hydrated with 4003 water molecules under periodic boundary conditions. The DNA fragment containing a cis-syn thymine dimer is composed of 634 atoms and the whole system contains a total of 12 661 atoms and 103 333 spherical Gaussian basis functions.
Interface-roughness parameters in InAs quantum wells determined from mobility
Authors: Gold A.
Published: March 2008

For zero temperature we present theoretical results for the transport properties of the electron gas in InAs quantum wells in the presence of interface-roughness scattering. We show how to analyze experimental data in connection with interface-roughness scattering. By comparison with recent experimental results obtained for the mobility of InAs quantum wells, we determine the interface roughness parameters as Δ=3.2Å and Λ=14Å. We predict the single-particle relaxation time (Dingle temperature) and a possible metal-insulator transition in these InAs quantum well structures.
Dipolar eddies in a decaying stratified turbulent flow
Authors: Voropayev S. I. , Fernando H. J. S. , Morrison R.
Published: March 2008

Laboratory experiments on the evolution of dipolar (momentum) eddies in a stratified fluid in the presence of random background motions are described. A turbulent jet puff was used to generate the momentum eddies, and a decaying field of ambient random vortical motions was generated by a towed grid. Data on vorticity/velocity fields of momentum eddies, those of background motions, and their interactions were collected in the presence and absence of the other, and the main characteristics thereof were parametrized. Similarity arguments predict that dipolar eddies in stratified fluids may preserve their identity in decaying grid-generated stratified turbulence, which was verified experimentally. Possible applications of the results include mushroomlike currents and other naturally/artificially generated large dipolar eddies in strongly stratified layers of the ocean, the longevity of which is expected to be determined by the characteristics of the eddies and random background motions.
Spectral and polarization responses of femtosecond laser-induced periodic surface structures on metals
Authors: Vorobyev A. Y. , Guo Chunlei
Published: March 2008

We study, for the first time, the spectral responsivity of femtosecond laser-induced periodic surface structures (FLIPSSs) in the UV, vis, and IR wavelength ranges. We find that FLIPSSs are an effective technique for controlling the optical properties of metals in the UV, vis, and near-IR spectral regions. In contrast to previous studies of FLIPSSs produced over an area of only a single irradiation spot on metals, we demonstrate that FLIPSSs can be produced over an extended area by scanning laser beam. This FLIPSS technique has potential applications in photonics, plasmonics, optoelectronics, thermal radiation sources, and bio-optical devices.
Steady-state electrical transport through block copolymer nanostructures deposited on smooth and rough electrodes
Authors: Křenek Radim , Stamm Manfred , Cimrová Věra
Published: March 2008

The influence of electrode roughness on formation of metallic nanostructures made via block copolymer nanotemplates was studied. Metallic nanostructures fabricated on electrodes with various roughnesses were prepared by sputtering the metals onto polystyrene-block-poly(4-vinylpyridine) nanotemplates. Their structure was characterized by atomic force microscopy and x-ray reflectivity. If the electrode roughness exceeds a critical value of about 1nm per 1×1μm2, an adhesion insulating thin film is formed between the electrode (substrate) and block copolymer nanotemplate. This insulating film strongly influences electrical contact with the substrate electrode. Steady-state current-voltage characteristics were studied for various configurations of the electrodes. They were analyzed and discussed in the frame of several injection and transport mechanism models.
Betavoltaics using scandium tritide and contact potential difference
Authors: Liu Baojun , Chen Kevin P. , Kherani Nazir P. , Zukotynski Stefan , Antoniazzi Armando B.
Published: March 2008

Tritium-powered betavoltaic micropower sources using contact potential difference (CPD) are demonstrated. Thermally stable scandium tritide thin films with a surface activity of 15mCi∕cm2 were used as the beta particle source. The electrical field created by the work function difference between the ScT film and a platinum or copper electrode was used to separate the beta-generated electrical charge carriers. Open circuit voltages of 0.5 and 0.16V and short circuit current densities of 2.7 and 5.3nA∕cm2 were achieved for gaseous and solid dielectric media-based CPD cells, respectively.
High-current electron beam generation in a diode with a multicapillary dielectric cathode
Authors: Gleizer J. Z. , Hadas Y. , Gurovich V. Tz. , Felsteiner J. , Krasik Ya. E.
Published: March 2008

Results of high-current electron beam generation in an ∼200kV, ∼250ns diode with a multicapillary dielectric cathode (MCDC) assisted by either velvet-type or ferroelectric plasma sources (FPSs) are presented. Multicapillary cathodes made of cordierite, glass, and quartz glass samples were studied. It was found that the source of electrons is the plasma ejected from capillaries. The plasma parameters inside capillary channels and in the vicinity of the cathode surface were determined during the accelerating pulse using visible range spectroscopy. It was shown that glass multicapillary cathodes are characterized by less surface erosion than the cordierite cathodes. Also, it was found that multicapillary cathodes assisted by a FPS showed longer lifetime and better vacuum compatibility than multicapillary cathodes assisted by a velvet-type igniter. Finally, it was found that quartz glass MCDC assisted by FPS is characterized by almost simultaneous formation of the plasma in a cross-sectional area of the dielectric sample with respect to the beginning of the accelerating pulse. The latter is explained by intense UV radiation which synchronized formation of parallel discharges due to induced secondary electron emission.
LED luminaires—a whole new light
Authors: Dowling Kevin
Published: March 2008

The light-emitting diodes that sit at the heart of integrated solid-state lighting systems, or luminaires, allow for novel applications but also present engineers with particular challenges.
Investigation of an Outbreak of Central Venous Catheter–Associated Bloodstream Infection Due to Contaminated Water
Authors: Douce Richard W. , Zurita Jeannete , Sanchez Olga , Aldaz Paul Cardenas
Published: March 2008

An outbreak of central venous catheter-associated bloodstream infections was reported in a hospital in Ecuador. Commercially produced ampoules of water for injection were found to be contaminated withBurkholderia cepaciaandMyroides odoratus.Removal of these ampoules yielded a 10-fold reduction in the incidence of catheter-associated infection.
Streamlined Gene Assembly PCR
Authors: Barnes Wayne M. , Frawley Elaine R.
Published: March 2008

INTRODUCTION

To construct genes with artificial, designed sequences, the temperature-cycling steps of the PCR process can be used to assemble whole genes and plasmids from identically sized pieces as small as 40 nucleotides. The original protocol for this process entailed two sequential PCR-like reactions. The first cycling protocol of 55 cycles (called “assembly”) contained no PCR primers per se; instead, the 40-mers all primed on each other, building up the product gene by extension of 20 bp at each extension step. In the second cycling protocol, real PCR primers were supplied, and 1-2 μL from the first PCR served as the template for an additional 23 cycles (for a total of 78 cycles). Finally, the PCR product was digested by restriction enzymes and gel-purified for cloning. The procedure presented here is a streamlined version of the original methodology, requiring only one round of 20-25 cycles to obtain a single or major product band, as detected by agarose gel analysis. This can be followed directly by cloning without gel-purification of the target DNA.
Preparation of Arabidopsis Tissue Sections of Fixed Material
Authors: Baum Stuart
Published: March 2008

INTRODUCTION

The best tissue sections are obtained from plastic-embedded material. These sections are more difficult and more expensive to prepare than those from Paraplast-embedded material, but the superior results make the additional effort worthwhile. The procedure starts with a fixative cocktail that includes a quickly penetrating fixative, such as paraformaldehyde, and one that is good for preserving fine structure, such as glutaraldehyde. Next, the samples are stained to facilitate manipulation of embedded tissue. After dehydration and staining, the tissue is infiltrated with resin. Finally, the embedded tissue is mounted and sectioned. The following protocol can be used on roots, leaves, shoot apices, and flowers, but the duration of infiltration must be adjusted for the various tissue types. Roots can be processed within 2 d, whereas leaves and flowers require up to 2 wk infiltration. Because Arabidopsis seedlings are small, whole seedlings (1-2 weeks old) can be fixed (including the root system) without dissection. Similarly, entire inflorescences, including those that have just opened, can be processed. Before embedding, the fixed material should be dissected to isolate organs of interest, such as individual flowers, to allow better orientation. Leaves from plants older than 2 wk should be cut into 1-cm2 pieces and fixed individually.
Computer-Based Analysis of the Optokinetic Response in Zebrafish Larvae
Authors: Hodel Corinne , Neuhauss Stephan C. F.
Published: March 2008

INTRODUCTION

Large movements in the visual field trigger stereotypic eye movements in vertebrates. This optokinetic response (OKR) is robust in zebrafish (Danio rerio) larvae older than 4 days post-fertilization (dpf), and is hence ideally suited for use in the evaluation of visual performance after genetic manipulations. This protocol describes a simple method by which a computer-generated visual stimulus is projected onto a screen and watched by immobilized larvae. The resulting eye movements are recorded and evaluated automatically, using a digital video camera and appropriate computer software. Depending on the sophistication of the software used, the evaluation can be performed in real time during the recording session, or by analyzing the recorded movie files off-line.
Phenotypic Analysis of Arabidopsis Mutants: Hypocotyl Length
Authors: Borevitz Justin , Neff Michael
Published: March 2008

INTRODUCTION

Hypocotyl elongation of young seedlings is an important response affected by both endogenous developmental programs and exogenous signals, such as light quality and quantity. When a seed germinates in the dark (as it might if it were buried in soil), the hypocotyl extends and the cotyledons remain folded under a protective hook. When the seedling reaches the light, the rate of hypocotyl elongation is inhibited, and vegetative development is initiated. This protocol describes the measurement of hypocotyl lengths in freshly germinated seedlings.
Strategies for Overcoming PCR Inhibition
Authors: Rådström Peter , Löfström Charlotta , Lövenklev Maria , Knutsson Rickard , Wolffs Petra
Published: March 2008

INTRODUCTION

The use of conventional and real-time PCR is to some extent restricted by the presence of PCR inhibitors. This is particularly so when the techniques are applied directly to complex biological samples such as clinical, environmental, or food samples for the detection of microorganisms. PCR inhibitors can originate from the sample itself, or as a result of the method used to collect or otherwise prepare the sample. Either way, inhibitors can dramatically reduce the sensitivity and amplification efficiency of PCR. This article discusses methods of reducing inhibition and designing reliable and sensitive conventional and real-time PCR experiments.
Genetic Analysis of Arabidopsis Mutants
Authors: Weigel Detlef , Glazebrook Jane
Published: March 2008

INTRODUCTION

The inheritance of mutant phenotypes in Arabidopsis thaliana is most often analyzed in the progeny resulting from crosses between different parents. This article describes genetic strategies for the analysis of mutants. Newly identified mutations can be examined initially using segregation analysis, followed by backcrossing and cosegregation for removal of extraneous mutations and assessment of pleiotropy. Confirmation that a phenotype of interest results from a given mutation can be achieved via complementation testing, which is also used to determine allelism of recessive mutations. The construction of double mutants is useful in the study of signal transduction and metabolic pathways. Considerations for the use of double homozygotes and their identification in the F2 and F3 generations are described at the end of this article.
Safety, tolerability and pharmacokinetics of udenafil, a novel PDE‐5 inhibitor, in healthy young Korean subjects
Authors: Kim Bo‐Hyung , Lim Hyeong‐Seok , Chung Jae‐Yong , Kim Jung‐Ryul , Lim Kyoung Soo , Sohn Dong‐Ryul , Cho Joo‐Youn , Yu Kyung‐Sang , Shin Sang‐Goo , Paick Jae‐Seung , Jang In‐Jin
Published: March 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The phosphodiesterase (PDE) type 5 inhibitor is a widely used agent that facilitates penile erection.

• Udenafil is newly developed as a PDE‐5 inhibitor.

WHAT THIS STUDY ADDS

• This is the first study to determine the safety, tolerability and pharmacokinetics of udenafil in healthy subjects.

• Udenafil was safe and well tolerated in healthy Korean subjects.

• The AUC and Cmax of udenafil increased supraproportionally with increasing dose upon single administration, but there was no significant drug accumulation upon multiple administrations.

AIM

To evaluate the safety, tolerability and pharmacokinetics (PK) of udenafil, a novel phosphodiesterase type 5 inhibitor.

METHODS

A double‐blind, randomized, placebo‐controlled, dose‐rising, parallel‐group, single‐ and multiple‐dose study was conducted in healthy Korean subjects. The subjects were allocated to single‐dose groups of 25, 50, 100, 200 or 300 mg (eight subjects in each dose group, including two placebos), or to multiple‐dose groups of 100 or 200 mg (once‐daily dosing for 7 days; nine subjects in each dose group, including three placebos). Serial samples of blood and urine were collected after oral administration and the drug concentrations in plasma and urine were determined by high‐performance liquid chromatography. Safety and tolerability were evaluated by monitoring clinical laboratory parameters and adverse events.

RESULTS

Udenafil reached peak plasma concentrations at 0.8–1.3 h, and then declined mono‐exponentially with a terminal half‐life of 7.3–12.1 h in the single‐dose study. The area under the time–concentration curves (AUC) and maximum plasma concentrations (Cmax) increased supraproportionally with increasing dose in the single‐dose study. During multiple dosing, a steady state was reached at 5 days and little accumulation occurred after repeated dosing for 7 days. Udenafil was generally well tolerated in these healthy subjects, and no serious adverse events occurred.

CONCLUSIONS

Udenafil was safe and well tolerated in healthy volunteers. The AUC and Cmax of udenafil increased supraproportionally with increasing dose upon single administration, but there was no significant drug accumulation upon multiple administrations.
Limited scope for maternal effects in aphid defence against parasitoids
Authors: VORBURGER CHRISTOPH , GEGENSCHATZ SILVAN E. , RANIERI GIULIA , RODRIGUEZ PAULA
Published: March 2008

Abstract1. A mother’s environment frequently affects her offspring’s phenotype. Such maternal effects may be adaptive, in particular with respect to pathogens or parasites, for example if maternal exposure increases offspring resistance.

2. In aphids, maternal effects are likely to occur as a result of their telescoping generations. This study investigated whether maternal effects influence the susceptibility of the peach‐potato aphid,Myzus persicae(Sulzer) (Hemiptera: Aphididae), to its parasitoidDiaeretiella rapae(M’Intosh) (Hymenoptera: Braconidae: Aphidiinae).

3. In a first experiment, susceptibility was compared among offspring of aphid mothers that had either no contact to parasitoids, had contact but were not attacked, or were attacked but not mummified. Mothers from the last group had successfully resisted the parasitoid.

4. In a second experiment using two different clones, maternal and progeny environment were manipulated by rearing each generation either on a benign (radish) or a more stressful host plant (silver beet) before progeny exposure to parasitoids.

5. The first experiment revealed no significant effect of the maternal treatment on offspring susceptibility to parasitoids and thus no evidence for trans‐generational defence. In the second experiment, maternal environment effects were also weak, yet with a trend towards less susceptible offspring of aphid mothers reared on the more stressful plant. However, there was a significant difference among clones and a strong clone × progeny host plant interaction, illustrating that the outcome of a parasitoid attack may be determined by a complex interplay of genetic and environmental factors.

6. Overall, the results suggest that there is limited scope for maternal effects in aphid defence against parasitoids.
Keratosis lichenoides chronica in an Indian child following erythroderma
Authors: Ghorpade Ashok
Published: March 2008

A 4‐year‐old boy presented with mildly itchy, linear, skin lesions over the trunk, arms, and face of 3 months’ duration. He had previously been admitted to a private hospital for generalized exfoliation of the skin following drug intake for fever and throat pain. The nature of the drugs was not known. The exfoliative dermatitis was treated with oral prednisolone, 10 mg daily, tapered over 3 weeks. No further topical or oral medication was given. The present skin lesions started 1 month after the cessation of the steroids. There was no family history of skin lesions, voice changes, or systemic complaints.

 Cutaneous examination showed multiple violaceous, linear, reticulate ridges with adherent scaling over the chest, back, and neck. There were scaly, flat‐topped papules over the extensor aspects of both upper arms and the buttocks, and scaly plaques over the cheeks (Figs 1a–d and 2a,b). The scalp showed diffuse greasy scaling. There were no oral, genital, axillary, or eye lesions. The nails were normal. Systemic examination did not reveal any abnormal finding.

(a,b) Violaceous, linear, reticulate ridges seen over the chest, and scaly papules on the upper arms. (c,d) Reticulate, linear, scaly lesions with flat papules over the back, and scaly papules on the buttocks

image

Linear ridges on the neck (a) and scaly plaques on the cheek (b)

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 Routine hematologic investigations, liver and kidney function tests, tests for hepatitis B and C, and enzyme‐linked immunosorbent assay (ELISA) for HIV were normal. Histopathology from skin lesions on the back revealed hyperkeratosis, patchy parakeratosis, follicular plugging, alternating irregular acanthosis and epidermal thinning, basal cell degeneration, and a band‐like inflammatory infiltrate of lymphocytes, histiocytes, and a few plasma cells (Fig. 3). Based on the classical clinical features and histopathology, keratosis lichenoides chronica was diagnosed, and topical 1% hydrocortisone acetate cream, twice daily, was prescribed. There was slight relief of pruritus at a follow‐up visit after 3 weeks; however, the patient was subsequently lost to follow‐up.

Histopathology showing hyperkeratosis, patchy parakeratosis, irregular acanthosis and epidermal thinning, and an upper dermal dense band‐like infiltrate of lymphocytes, histiocytes, and a few plasma cells with melanin incontinence (hematoxylin and eosin; original magnification, ×40)

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Treatment of fatigue in multiple sclerosis: A systematic review of the literature
Authors: Lee David , Newell Robert , Ziegler Lucy , Topping Annie
Published: March 2008

Fatigue is common in people with multiple sclerosis (MS) and symptoms of fatigue are often reported as the most debilitating symptoms of the disease. However, there are few reports of interventions for fatigue in MS. A systematic review of published literature examining pharmacological and psychosocial/psychological interventions for fatigue in MS was conducted. The search and review strategy undertaken used the Centre for Reviews and Dissemination guidelines. Papers were reviewed by two independent reviewers. Of 81 studies short‐listed for inclusion, 15 studies were included, of which 10 were studies of pharmacological therapy and five were studies of psychosocial/psychological interventions. Of the pharmacological studies, two were rated as of moderate‐to‐high quality, three of moderate quality, two of moderate‐to‐low quality and three of low quality. Of the psychosocial/psychological studies, three were rated as of moderate quality and two of moderate‐to‐low quality. None of the studies reviewed reached the highest level of quality according to pre‐agreed criteria. Regardless of level of quality, effectiveness of both pharmacological and psychosocial/psychological interventions was modest at best and often absent. Accordingly, there is little evidence‐based advice that can be offered to people with MS to help manage their fatigue.
Positive attitude in cancer: The nurse's perspective
Authors: O'Baugh Jenny , Wilkes Lesley M , Luke Suzanne , George Ajesh
Published: March 2008

This paper reports the findings of a qualitative descriptive study, which explored the meaning of ‘positive attitude’ for a group of oncology nurses. Unstructured interviews were conducted with eight female nurses who volunteered to participate in the study. The importance and impact of attitude to patients with cancer and definitions of positive and negative attitude as perceived by nurses were key concepts addressed. The audio‐taped interviews were transcribed and analysed for themes that related to positive attitude and cancer. The nurses perceived hope and positive attitude as similar and used three broad themes to describe this multifaceted construct: acceptance, a fighting spirit and looking on the bright side. The nurses perceived to have a major influence on the positive attitude of the cancer patient. However, they acknowledged their obligation to support and encourage patients to maintain a sense of positivity based on patient's values and beliefs.
The lived experience of gay men caring for others with HIV/AIDS: Resilient coping skills
Authors: Munro Ian , Edward Karen‐Leigh
Published: March 2008

There is a dearth of research conducted on the relationship aspect of gay men caring for gay men. This Australian research conducted in 2002 investigated the emotional effects of HIV/AIDS on the gay male carers of gay men with the disease. This study was phenomenological inquiry and employed van Manen's approach to content analysis. Twelve participants for the study were recruited. The results produced emergent themes relating to coping with HIV/AIDS, living day‐to‐day with HIV/AIDS, coping with the last phase of AIDS towards death, saying goodbye and remembrance. This research highlights the resilient coping style of carers of persons living with HIV/AIDS. The research also gives rise to recommendations for practice and educational contexts in terms of the support and care considerations for persons living with HIV/AIDS and their carers.
Novel uncultured Chloroflexi dechlorinate perchloroethene to trans‐dichloroethene in tidal flat sediments
Authors: Kittelmann Sandra , Friedrich Michael W.
Published: March 2008

The marine environment represents a rich source of bio‐ and geogenically produced organohalogens, including the common pollutant perchloroethene (PCE). However, diversity and function of marine chloroethene‐dechlorinating microorganisms are largely unknown. Here, we have studied the activity and composition of a tidal flat sediment bacterial and archaeal community from the North Sea exposed to low concentrations of PCE. After 2 weeks of incubation, PCE was rapidly dechlorinated via trichloroethene to dichloroethene (DCE). Unexpectedly, these microcosms produced 3.5‐fold more trans‐DCE than cis‐DCE. The actively dechlorinating microbial populations were traced by stable isotope probing of rRNA with 13C‐labelled acetate for 4 days. Terminal restriction fragment length polymorphism fingerprinting and clone libraries of isotopically enriched, ‘heavy’13C‐labelled bacterial 16S rRNA revealed the populations potentially involved in reductive dechlorination. Major clone groups belonged to the Proteobacteria (50.0%; 22.4% δ‐, 12.1% γ‐, 6.9% α‐, 6.9% β‐ and 1.7% ε‐subgroup) and Chloroflexi (29.3%). Populations represented by the two dominant terminal restriction fragments were affiliated with the Dehalococcoidetes (subphylum II of the Chloroflexi), and were exclusively detected in the heavy fraction of the PCE‐dechlorinating incubation. The phylogenetically novel, larger population, designated Tidal Flat Chloroflexi Cluster, was closely related to the recently discovered PCE‐dechlorinating Lahn Cluster bacteria from anoxic river sediment but more distantly related to canonical Dehalococcoides spp. (92–94% sequence identity). The second population was closely related to ‘Dehalobium chlorocoercia DF‐1’. Both populations appear to be responsible for reductive dechlorination of highly chlorinated ethenes to predominantly trans‐DCE in tidal flat sediment incubations.
Colonoscopy for screening and follow up of patients with a family history of colorectal cancer
Authors: Tytherleigh M. G. , Ng V. V. , Mathew L. O. , Banerjee T. , Menon K. V. , Mee A. S. , Farouk R.
Published: March 2008

Objective  To determine the minimum family history of colorectal cancer (CRC), which justifies colonoscopy and to establish whether further colonic assessment is necessary after a negative screening colonoscopy.

Method  A retrospective review of every colonoscopy undertaken for family screening at the Royal Berkshire and Battle Hospitals, Reading between October 1996 and July 2004.

Results  Four hundred and thirty‐two patients (261 women) with an average age of 48 years (range 14–84) were screened. Three cancers in patients over the age of 60 years and 49 adenomas were found in 37 patients. Twenty three of 281 (8%) patients with a ‘low‐risk’ family history (one in 12 or less lifetime risk of developing CRC) had either a cancer or an adenoma. Eighteen of 151 (12%) patients with a ‘high‐risk’ family history (one in 10 or greater) had a similar positive colonoscopy. Thirteen of 15 patients who had an adenoma aged under 45 years had a high‐risk family history. Seventy‐three patients subsequently underwent two or more follow‐up colonoscopies. There were 22 adenomatous polyps found in 12 patients (16%) at the first screening, nine adenomas in seven patients in the second colonoscopy and four adenomas found in four patients in all subsequent colonoscopies.

Conclusion  Patients with a low‐risk family history have a similar adenoma pick‐up to that of the general population. These patients need not be screened below the age of 50 unless symptomatic. Follow up of low‐risk family history (FH) patients with a negative screening colonoscopy is unlikely to be beneficial.
Involvement of surgical trainees in surgery for colorectal cancer and their effect on outcome
Authors: Borowski D. W. , Ratcliffe A. A. , Bharathan B. , Gunn A. , Bradburn D. M. , Mills S. J. , Wilson R. G. , Kelly S. B. ,   the members of the Northern Region Colorectal Cancer Audit Group (NORCCAG)
Published: March 2008

Objective  Surgical training in the UK is undergoing substantial changes. This study assessed: 1) the training opportunities available to trainees in operations for colorectal cancer, 2) the effect of colorectal specialization on training, and 3) the effect of consultant supervision on anastomotic complications, postoperative stay, operative mortality and 5‐year survival.

Method  Unadjusted and adjusted comparisons of outcomes were made for unsupervised trainees, supervised trainees and consultants as the primary surgeon in 7411 operated patients included in the Northern Region Colorectal Cancer Audit between 1998 and 2002.

Results  Surgery was performed in 656 (8.8%) patients by unsupervised trainees and in 1578 (21.3%) patients by supervised trainees. Unsupervised operations reduced from 182 (12.4%) in 1998 to 82 (6.1%) in 2002 (P < 0.001). Consultants with a colorectal specialist interest were more likely than nonspecialists to be present at surgical resections (OR 1.35, 1.12–1.63, P = 0.001) and to provide supervised training (OR 1.34, 1.17–1.53, P < 0.001). Patients operated on by unsupervised trainees were more often high‐risk patients, however, consultant presence was not significantly associated with operative mortality (OR 0.83, 0.63–1.09, P = 0.186) or survival (HR 1.02, 0.92–1.13, P = 0.735) in risk‐adjusted analysis. Supervised trainees had a case‐mix similar to consultants, with shorter length of hospital stay (11.4 vs 12.4 days, P < 0.001), but similar mortality (OR 0.90, 0.71–1.16, 0.418) and survival (HR 0.96, 0.89–1.05, P = 0.378).

Conclusion  One third of patients were operated on by trainees, who were more likely to perform supervised resections in colorectal teams. There was no difference in anastomotic leaks rates, operative mortality or survival between unsupervised trainees, supervised trainees and consultants when case‐mix adjustment was applied. This study would suggest that there is considerable underused training capacity available.
PLANNING FOR THE FUTURE: Planning for the 2040s: everybody's business
Authors: Mittler Peter
Published: March 2008

As we mark the publication of the 35th issue of the British Journal of Special Education, Peter Mittler, Emeritus Professor of Special Needs Education at the University of Manchester, looks into the future and asks a series of challenging questions: What kind of a future do we want to see for a baby born with a significant disability today? What changes will be needed in society and in our schools both for the child and for the family? What reforms might this year's newly qualified staff bring about in our schools and services and in society as a whole by the time they retire in the 2040s? Professor Mittler proposes that the time is ripe to take advantage of new international and national opportunities to lay the foundations for a society that fully includes disabled people and safeguards their basic human rights. He argues that each one of us can help to determine the values and priorities of the society in which today's baby will grow up and suggests that the Make Poverty History movement has provided powerful evidence that the voice of ordinary citizens can shape policies and set priorities. He encourages us all to think globally and to act locally on a host of issues, including supporting families, planning for transition, promoting quality of life, professional development and challenging inequality.